Satellite recovery - Attitude dynamics of the targets

NASA Technical Reports Server (NTRS)

Cochran, J. E., Jr.; Lahr, B. S.

1986-01-01

The problems of categorizing and modeling the attitude dynamics of uncontrolled artificial earth satellites which may be targets in recovery attempts are addressed. Methods of classification presented are based on satellite rotational kinetic energy, rotational angular momentum and orbit and on the type of control present prior to the benign failure of the control system. The use of approximate analytical solutions and 'exact' numerical solutions to the equations governing satellite attitude motions to predict uncontrolled attitude motion is considered. Analytical and numerical results are presented for the evolution of satellite attitude motions after active control termination.

Interior and exterior ballistics coupled optimization with constraints of attitude control and mechanical-thermal conditions

NASA Astrophysics Data System (ADS)

Liang, Xin-xin; Zhang, Nai-min; Zhang, Yan

2016-07-01

For solid launch vehicle performance promotion, a modeling method of interior and exterior ballistics associated optimization with constraints of attitude control and mechanical-thermal condition is proposed. Firstly, the interior and external ballistic models of the solid launch vehicle are established, and the attitude control model of the high wind area and the stage of the separation is presented, and the load calculation model of the drag reduction device is presented, and thermal condition calculation model of flight is presented. Secondly, the optimization model is established to optimize the range, which has internal and external ballistic design parameters as variables selected by sensitivity analysis, and has attitude control and mechanical-thermal conditions as constraints. Finally, the method is applied to the optimal design of a three stage solid launch vehicle simulation with differential evolution algorithm. Simulation results are shown that range capability is improved by 10.8%, and both attitude control and mechanical-thermal conditions are satisfied.

Students' Attitudes towards Control Methods in Computer-Assisted Instruction.

ERIC Educational Resources Information Center

Hintze, Hanne; And Others

1988-01-01

Describes study designed to investigate dental students' attitudes toward computer-assisted teaching as applied in programs for oral radiology in Denmark. Programs using personal computers and slide projectors with varying degrees of learner and teacher control are described, and differences in attitudes between male and female students are…

Model predictive control of attitude maneuver of a geostationary flexible satellite based on genetic algorithm

NASA Astrophysics Data System (ADS)

TayyebTaher, M.; Esmaeilzadeh, S. Majid

2017-07-01

This article presents an application of Model Predictive Controller (MPC) to the attitude control of a geostationary flexible satellite. SIMO model has been used for the geostationary satellite, using the Lagrange equations. Flexibility is also included in the modelling equations. The state space equations are expressed in order to simplify the controller. Naturally there is no specific tuning rule to find the best parameters of an MPC controller which fits the desired controller. Being an intelligence method for optimizing problem, Genetic Algorithm has been used for optimizing the performance of MPC controller by tuning the controller parameter due to minimum rise time, settling time, overshoot of the target point of the flexible structure and its mode shape amplitudes to make large attitude maneuvers possible. The model included geosynchronous orbit environment and geostationary satellite parameters. The simulation results of the flexible satellite with attitude maneuver shows the efficiency of proposed optimization method in comparison with LQR optimal controller.

Impact of Family Planning Health Education on the Knowledge and Attitude among Yasoujian Women

PubMed Central

Mahamed, Fariba; Parhizkar, Saadat; Shirazi, Alireza Raygan

2012-01-01

The aim of this study was to determine the effect of health education on the knowledge and attitude regarding family planning and contraception’s method among the women who obligatory attended the Premarital Counseling Center in Yasouj city, Iran. An experimental study was carried out and a total of 200 women were selected for the study using convenience sampling method among women who attended in the health centre in order to utilize the necessary premarital actions. Respondents were divided by two experimental and control groups randomly. A pre-evaluation was done on the knowledge and attitude on family planning using a structured questionnaire. After which, the health education for experimental group was done within four educational sessions during 4 consecutive weeks and control group underwent traditional education method. Post evaluation was utilized for any changes regarding their knowledge and attitude among the respondents immediately after the intervention. Independent and paired t-test was used to evaluate the mean knowledge and attitude scores differences among both groups. Results showed that there was a significant improvement in respondents’ knowledge and attitude after educational program in experimental group (p<0.001), while no significant difference was observed in knowledge and attitude of control group. The finding also indicated that age was significantly associated with the level of respondents’ knowledge. These results deal the effectiveness of the educational method. In conclusion, the educational method is effective in increasing the knowledge and improving the attitude of women regarding family planning in Yasouj compared to current used educational method. Future educational programs need to incorporate the features that have been associated with successful interventions in the past, as well as including their own evaluation procedures. PMID:22980158

Coupled attitude-orbit dynamics and control for an electric sail in a heliocentric transfer mission.

PubMed

Huo, Mingying; Zhao, Jun; Xie, Shaobiao; Qi, Naiming

2015-01-01

The paper discusses the coupled attitude-orbit dynamics and control of an electric-sail-based spacecraft in a heliocentric transfer mission. The mathematical model characterizing the propulsive thrust is first described as a function of the orbital radius and the sail angle. Since the solar wind dynamic pressure acceleration is induced by the sail attitude, the orbital and attitude dynamics of electric sails are coupled, and are discussed together. Based on the coupled equations, the flight control is investigated, wherein the orbital control is studied in an optimal framework via a hybrid optimization method and the attitude controller is designed based on feedback linearization control. To verify the effectiveness of the proposed control strategy, a transfer problem from Earth to Mars is considered. The numerical results show that the proposed strategy can control the coupled system very well, and a small control torque can control both the attitude and orbit. The study in this paper will contribute to the theory study and application of electric sail.

Coupled Attitude-Orbit Dynamics and Control for an Electric Sail in a Heliocentric Transfer Mission

PubMed Central

Huo, Mingying; Zhao, Jun; Xie, Shaobiao; Qi, Naiming

2015-01-01

The paper discusses the coupled attitude-orbit dynamics and control of an electric-sail-based spacecraft in a heliocentric transfer mission. The mathematical model characterizing the propulsive thrust is first described as a function of the orbital radius and the sail angle. Since the solar wind dynamic pressure acceleration is induced by the sail attitude, the orbital and attitude dynamics of electric sails are coupled, and are discussed together. Based on the coupled equations, the flight control is investigated, wherein the orbital control is studied in an optimal framework via a hybrid optimization method and the attitude controller is designed based on feedback linearization control. To verify the effectiveness of the proposed control strategy, a transfer problem from Earth to Mars is considered. The numerical results show that the proposed strategy can control the coupled system very well, and a small control torque can control both the attitude and orbit. The study in this paper will contribute to the theory study and application of electric sail. PMID:25950179

Attitude dynamics and control of spacecraft with a partially filled liquid tank and flexible panels

NASA Astrophysics Data System (ADS)

Liu, Feng; Yue, Baozeng; Zhao, Liangyu

2018-02-01

A liquid-filled flexible spacecraft is essentially a time-variant fully-coupled system, whose dynamics characteristics are closely associated with its motion features. This paper focuses on the mathematical modelling and attitude control of the spacecraft coupled with fuel sloshing dynamics and flexible solar panels vibration. The slosh motion is represented by a spherical pendulum, whose motion description method is improved by using split variable operation. Benefiting from this improvement, the nonlinear lateral sloshing and the rotary sloshing as well as the rigid motion of a liquid respect to the spacecraft can be approximately described. The assumed modes discretization method has been adopted to approximate the elastic displacements of the attached panels, and the coupled dynamics is derived by using the Lagrangian formulation. A variable substitution method is proposed to obtain the apparently-uncoupled mathematical model of the rigid-flexible-liquid spacecraft. After linearization, this model can be directly used for designing Lyapunov output-feedback attitude controller (OFAC). With only torque actuators, and attitude and rate sensors installed, this kind of attitude controller, as simulation results show, is capable of not only bringing the spacecraft to the desired orientation, but also suppressing the effect of flex and slosh on the attitude motion of the spacecraft.

Predictors of Attitudes toward Childlessness.

ERIC Educational Resources Information Center

Spreadbury, Connie

The study assessed young adults' attitudes toward childlessness and identified certain factors which predict positive or negative attitudes toward childlessness. The author anticipated finding changes in attitudes because of recent social developments such as awareness of world overpopulation, availability of birth control methods, pressure for…

Attitude Control of Nanosatellites by Paddle Motion Using Elastic Hinges Actuated by Shape Memory Alloy

NASA Astrophysics Data System (ADS)

Iai, Masafumi; Durali, Mohammad; Hatsuzawa, Takeshi

Recent research has been extending the applications of small satellites called microsatellites, nanosatellites, or picosatellites. To further improve capability of those satellites, a lightweight, active attitude-control mechanism is needed. This paper proposes a concept of inertial orientation control, an attitude control method using movable solar arrays. This method is made suitable for nanosatellites by the use of shape memory alloy (SMA)-actuated elastic hinges and a simple maneuver generation algorithm. The combination of SMA and an elastic hinge allows the hinge to remain lightweight and free of frictional or rolling contacts. Changes in the shrinking and stretching speeds of the SMA were measured in a vacuum chamber. The proposed algorithm constructs a maneuver to achieve arbitrary attitude change by repeating simple maneuvers called unit maneuvers. Provided with three types of unit maneuvers, each degree of freedom of the satellite can be controlled independently. Such construction requires only simple calculations, making it a practical algorithm for a nanosatellite with limited computational capability. In addition, power generation variation caused by maneuvers was analyzed to confirm that a maneuver from any initial attitude to an attitude facing the sun was justifiable in terms of the power budget.

The Association Between Implicit and Explicit Attitudes Toward Smoking and Support for Tobacco Control Measures

PubMed Central

Chassin, Laurie; Presson, Clark C.

2013-01-01

Introduction: This study examined the association between implicit and explicit attitudes toward smoking and support for tobacco control policies. Methods: Participants were from an ongoing longitudinal study of the natural history of smoking who also completed a web-based assessment of implicit attitudes toward smoking (N = 1,337). Multiple regression was used to test the association between covariates (sex, age, educational attainment, parent status, and smoking status), implicit attitude toward smoking, and explicit attitude toward smoking and support for tobacco control policies. The moderating effect of the covariates on the relation between attitudes and support for policies was also tested. Results: Females, those with higher educational attainment, parents, and nonsmokers expressed more support for tobacco control policy measures. For nonsmokers, only explicit attitude was significantly associated with support for policies. For smokers, both explicit and implicit attitudes were significantly associated with support. The effect of explicit attitude was stronger for those with lower educational attainment. Conclusions: Both explicit and implicit smoking attitudes are important for building support for tobacco control policies, particularly among smokers. More research is needed on how to influence explicit and implicit attitudes to inform policy advocacy campaigns. PMID:22581941

Experimental study on line-of-sight (LOS) attitude control using control moment gyros under micro-gravity environment

NASA Astrophysics Data System (ADS)

Kojima, Hirohisa; Hiraiwa, Kana; Yoshimura, Yasuhiro

2018-02-01

This paper presents the results of line-of-sight (LOS) attitude control using control moment gyros under a micro-gravity environment generated by parabolic flight. The W-Z parameters are used to describe the spacecraft attitude. In order to stabilize the current LOS to the target LOS, backstepping-based feedback control is considered using the W-Z parameters. Numerical simulations and experiments under a micro-gravity environment are carried out, and their results are compared in order to validate the proposed control methods.

Satellite Dynamic Damping via Active Force Control Augmentation

NASA Astrophysics Data System (ADS)

Varatharajoo, Renuganth

2012-07-01

An approach that incorporates the Active Force Control (AFC) technique into a conventional Proportional-Derivative (PD) controller is proposed for a satellite active dynamic damping towards a full attitude control. The AFC method has been established to facilitate a robust motion control of dynamical systems in the presence of disturbances, parametric uncertainties and changes that are commonly prevalent in the real-world environment. The usefulness of the method can be extended by introducing intelligent mechanisms to approximate the mass or inertia matrix of the dynamic system to trigger the compensation effect of the controller. AFC is a technique that relies on the appropriate estimation of the inertial or mass parameters of the dynamic system and the measurements of the acceleration and force signals induced by the system if practical implementation is ever considered. In AFC, it is shown that the system subjected to a number of disturbances remains stable and robust via the compensating action of the control strategy. We demonstrate that it is possible to design a spacecraft attitude feedback controller that will ensure the system dynamics set point remains unchanged even in the presence of the disturbances provided that the actual disturbances can be modeled effectively. In order to further facilitate this analysis, a combined energy and attitude control system (CEACS) is proposed as a model satellite attitude control actuator. All the governing equations are established and the proposed satellite attitude control architecture is made amenable to numerical treatments. The results show that the PD-AFC attitude damping performances are superiorly better than that of the solely PD type. It is also shown that the tunings of the AFC system gains are crucial to ensure a better attitude damping performance and this process is mandatory for AFC systems. Finally, the results demonstrate an important satellite dynamic damping enhancement capability using the AFC technique. Keywords: Satellite, Dynamic Damping, Attitude Control, AFC Technique,

Micropulsed Plasma Thrusters for Attitude Control of a Low-Earth-Orbiting CubeSat

NASA Technical Reports Server (NTRS)

Gatsonis, Nikolaos A.; Lu, Ye; Blandino, John; Demetriou, Michael A.; Paschalidis, Nicholas

2016-01-01

This study presents a 3-Unit CubeSat design with commercial-off-the-shelf hardware, Teflon-fueled micropulsed plasma thrusters, and an attitude determination and control approach. The micropulsed plasma thruster is sized by the impulse bit and pulse frequency required for continuous compensation of expected maximum disturbance torques at altitudes between 400 and 1000 km, as well as to perform stabilization of up to 20 deg /s and slew maneuvers of up to 180 deg. The study involves realistic power constraints anticipated on the 3-Unit CubeSat. Attitude estimation is implemented using the q method for static attitude determination of the quaternion using pairs of the spacecraft-sun and magnetic-field vectors. The quaternion estimate and the gyroscope measurements are used with an extended Kalman filter to obtain the attitude estimates. Proportional-derivative control algorithms use the static attitude estimates in order to calculate the torque required to compensate for the disturbance torques and to achieve specified stabilization and slewing maneuvers or combinations. The controller includes a thruster-allocation method, which determines the optimal utilization of the available thrusters and introduces redundancy in case of failure. Simulation results are presented for a 3-Unit CubeSat under detumbling, pointing, and pointing and spinning scenarios, as well as comparisons between the thruster-allocation and the paired-firing methods under thruster failure.

Weight Control Beliefs, Body Shape Attitudes, and Physical Activity among Adolescents

ERIC Educational Resources Information Center

Martin, Scott B.; Rhea, Deborah J.; Greenleaf, Christy A.; Judd, Doryce E.; Chambliss, Heather O.

2011-01-01

Background: Relatively little is known about how perceived weight controllability influences important psychological health factors among adolescents. Thus, the purpose of this study is to explore adolescents' weight controllability beliefs and how those beliefs influence weight-related attitudes and behaviors. Methods: Adolescents (N = 369, mean…

Compensation of an attitude disturbance torque caused by magnetic substances in LEO satellites

NASA Astrophysics Data System (ADS)

Inamori, Takaya; Wang, Jihe; Saisutjarit, Phongsatorn; Ohsaki, Hiroyuki

This research considers an attitude disturbance torque caused by ferromagnetic substances in a LEO satellite. In most LEO satellite missions, a gravity gradient torque, solar pressure torque, aerodynamic torque, and magnetic dipole moment torque are considered for their attitude control systems, however, the effect of the ferromagnetic substances causing a disturbance torque in the geomagnetic field is not considered in previous satellite missions. The ferromagnetic substances such as iron cores of MTQs and a magnetic hysteresis damper for a passive attitude control system are used in various small satellites. These substances cause a disturbance torque which is almost the same magnitude of the dipole magnetic disturbance and the dominant disturbance in the worst cases. This research proposes a method to estimate and compensate for the effect of the ferromagnetic substances using an extended Kalman filter. From simulation results, the research concludes that the proposed method is useful and attractive for precise attitude control for LEO satellite missions.

Comparison of thruster configurations in attitude control systems. M.S. Thesis. Progress Report

NASA Technical Reports Server (NTRS)

Boland, J. S., III; Drinkard, D. M., Jr.; White, L. R.; Chakravarthi, K. R.

1973-01-01

Several aspects concerning reaction control jet systems as used to govern the attitude of a spacecraft were considered. A thruster configuration currently in use was compared to several new configurations developed in this study. The method of determining the error signals which control the firing of the thrusters was also investigated. The current error determination procedure is explained and a new method is presented. Both of these procedures are applied to each of the thruster configurations which are developed and comparisons of the two methods are made.

The effects of traditional learning and a learning cycle inquiry learning strategy on students' science achievement and attitudes toward elementary science

NASA Astrophysics Data System (ADS)

Ebrahim, Ali

The purpose of this study is to examine the impact of two instructional methods on students' academic achievement and attitudes toward elementary science in the State of Kuwait: traditional teaching method and the 4-E learning cycle inquiry teaching method. The subjects were 111 students from four intact 4th grade classes. The experiment group (n = 56) received the learning cycle instruction while the control group (n = 55) received a more traditional approach over a four week period. The same female teacher taught the experimental and control groups for boys and a different female teacher taught experimental and control groups for girls. The dependent variables were measured through the use of: (1) a science achievement test to assess student achievement; and (2) an attitude survey to measure students' attitudes toward science. Quantitative data were collected on students' pre- and post-treatment achievement and attitudes measures. The two way MANOVA reveals that: the 4-E learning cycle instructional method produces significantly greater achievement and attitudes among fourth grade science students than the traditional teaching approach F (2, 93) = 19.765, (P = .000), corresponding to Wilks' Lambda = .702 with an effect size of .298 and a power of 1. In light of these findings, it is therefore suggested that students can achieve greater and have higher science attitudes when the 4-E learning cycle is used. In addition, these findings support the notion that effective instruction in teaching science, such as the 4-E learning cycle instruction, should be proposed and implemented in elementary schools.

The impact of group training about parenting styles on maternal attitudes toward parenting styles

PubMed Central

Zandiyeh, Zahra; Zare, Elaheh; Hedayati, Batool

2015-01-01

Background: Parenting style is one of the most important and effective factors in training and growth of children and adolescents and the method that parents communicate with their children is an effective factor on family contact models. Objectives: The aim of this study was to determine the impact of group training about parenting styles on maternal attitudes that were admitted to Isfahan Imam Ali (AS) health care center in 2013. Materials and Methods: This was an experimental study, which was conducted on a random sample of 25 mothers referred to this health care center. They were divided into two groups (experimental and control). The experimental group received five sessions of group training, and the control group received a booklet about parenting styles. The used tool in this study was the Bamerind Parenting Style Questionnaire that was completed by the mothers before and after the intervention and finally, their obtained scores were compared with each other. Results: The results of the present study showed that the mean score of attitude toward easy-going style in test group was less than the control group after intervention (P = 0.045). The mean score of attitude toward authoritative style in the experimental group was less than control group after intervention (P = 0.037) and the mean score of attitude toward authoritative style in the experimental group was more than the control group after intervention (P = 0.011). Conclusions: Group training can be an appropriate method in changing maternal attitudes toward parenting styles. PMID:27462627

Velocity-free attitude coordinated tracking control for spacecraft formation flying.

PubMed

Hu, Qinglei; Zhang, Jian; Zhang, Youmin

2018-02-01

This article investigates the velocity-free attitude coordinated tracking control scheme for a group of spacecraft with the assumption that the angular velocities of the formation members are not available in control feedback. Initially, an angular velocity observer is constructed based on each individual's attitude quarternion. Then, the distributed attitude coordinated control law is designed by using the observed states, in which adaptive control method is adopted to handle the external disturbances. Stability of the overall closed-loop system is analyzed theoretically, which shows the system trajectory converges to a small set around origin with fast convergence rate. Numerical simulations are performed to demonstrate fast convergence and improved tracking performance of the proposed control strategy. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Attitude orientation control for a spinning satellite

NASA Astrophysics Data System (ADS)

Frost, Gerald

The Department of the Air Force, Headquarters Space Systems Division, and the National Aeronautics and Space Administration (NASA) are currently involved in litigation with Hughes Aircraft Company over the alledged infringement of the 'Williams patent,' which describes a method for attitude control of a spin-stabilized vehicle. Summarized here is pre-1960 RAND work on this subject and information obtained from RAND personnel knowledgeable on this subject. It was concluded that there is no RAND documentation that directly parallels the 'Williams patent' concept. Also, the TIROS II magnetic torque attitude control method is reviewed. The TIROS II meteorological satellite, launched on November 23, 1960, incorporated a magnetic actuation system for spin axis orientation control. The activation system was ground controlled to orient the satellite spin axis to obtain the desired pointing direction for optical and infrared sensor subsystems.

Application Number 3: Using Tethers for Attitude Control

NASA Technical Reports Server (NTRS)

Muller, R. M.

1985-01-01

Past application of the gravity gradient concept to satellite attitude control produced attitude stabilities of from 1 to 10 degrees. The satellite members were rigigly interconnected and any motion in one part of the satellite would cause motion in all members. This experience has restricted gravity gradient stabilization to applications that need attitude stability no better than 1 degree. A gravity gradient technique that combines the flexible tether with an active control that will allow control stability much better than 1 degree is proposed. This could give gravity gradient stabilization much broader application. In fact, for a large structure like a space station, it may become the preferred method. Two possible ways of demonstrating the techniques using the Tethered Satellite System (TSS) tether to control the attitude of the shuttle are proposed. Then a possible space station tether configuration is shown that could be used to control the initial station. It is then shown how the technique can be extended to the control of space stations of virtually any size.

A novel body frame based approach to aerospacecraft attitude tracking.

PubMed

Ma, Carlos; Chen, Michael Z Q; Lam, James; Cheung, Kie Chung

2017-09-01

In the common practice of designing an attitude tracker for an aerospacecraft, one transforms the Newton-Euler rotation equations to obtain the dynamic equations of some chosen inertial frame based attitude metrics, such as Euler angles and unit quaternions. A Lyapunov approach is then used to design a controller which ensures asymptotic convergence of the attitude to the desired orientation. Although this design methodology is pretty standard, it usually involves singularity-prone coordinate transformations which complicates the analysis process and controller design. A new, singularity free error feedback method is proposed in the paper to provide simple and intuitive stability analysis and controller synthesis. This new body frame based method utilizes the concept of Euleraxis and angles to generate the smallest error angles from a body frame perspective, without coordinate transformations. Global tracking convergence is illustrated with the use of a feedback linearizing PD tracker, a sliding mode controller, and a model reference adaptive controller. Experimental results are also obtained on a quadrotor platform with unknown system parameters and disturbances, using a boundary layer approximated sliding mode controller, a PIDD controller, and a unit sliding mode controller. Significant tracking quality is attained. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

The influence of contextual teaching with the problem solving method on students' knowledge and attitudes toward horticulture, science, and school

NASA Astrophysics Data System (ADS)

Whitcher, Carrie Lynn

2005-08-01

Adolescence is marked with many changes in the development of higher order thinking skills. As students enter high school they are expected to utilize these skills to solve problems, become abstract thinkers, and contribute to society. The goal of this study was to assess horticultural science knowledge achievement and attitude toward horticulture, science, and school in high school agriculture students. There were approximately 240 high school students in the sample including both experimental and control groups from California and Washington. Students in the experimental group participated in an educational program called "Hands-On Hortscience" which emphasized problem solving in investigation and experimentation activities with greenhouse plants, soilless media, and fertilizers. Students in the control group were taught by the subject matter method. The activities included in the Hands-On Hortscience curriculum were created to reinforce teaching the scientific method through the context of horticulture. The objectives included evaluating whether the students participating in the Hands-On Hortscience experimental group benefited in the areas of science literacy, data acquisition and analysis, and attitude toward horticulture, science, and school. Pre-tests were administered in both the experimental and control groups prior to the research activities and post-tests were administered after completion. The survey questionnaire included a biographical section and attitude survey. Significant increases in hortscience achievement were found from pre-test to post-test in both control and experimental study groups. The experimental treatment group had statistically higher achievement scores than the control group in the two areas tested: scientific method (p=0.0016) and horticulture plant nutrition (p=0.0004). In addition, the students participating in the Hands-On Hortscience activities had more positive attitudes toward horticulture, science, and school (p=0.0033). Students who were more actively involved in hands-on projects had higher attitude scores compared to students who were taught traditional methods alone. In demographic comparisons, females had more positive attitudes toward horticulture science than males; and students from varying ethnic backgrounds had statistically different achievement (p=0.0001). Ethnicity was determined with few students in each background, 8 in one ethnicity and 10 students in another. Youth organization membership such as FFA or 4-H had no significant bearing on achievement or attitude.

Anti-sway control of tethered satellite systems using attitude control of the main satellite

NASA Astrophysics Data System (ADS)

Yousefian, Peyman; Salarieh, Hassan

2015-06-01

In this study a new method is introduced to suppress libration of a tethered satellite system (TSS). It benefits from coupling between satellites and tether libration dynamics. The control concept uses the main satellite attitude maneuvers to suppress librational motion of the tether, and the main satellite's actuators for attitude control are used as the only actuation in the system. The study considers planar motion of a two body TSS system in a circular orbit and it is assumed that the tether's motion will not change it. Governing dynamic equations of motion are derived using the extended Lagrange method. Controllability of the system around the equilibrium state is studied and a linear LQG controller is designed to regulate libration of the system. Tether tension and satellite attitude are assumed as only measurable outputs of the system. The Extended Kalman Filter (EKF) is used to estimate states of the system to be used as feedback to the controller. The designed controller and observer are implemented to the nonlinear plant and simulations demonstrate that the controller lead to reduction of the tether libration propoerly. By the way, because the controller is linear, it is applicable only at low amplitudes in the vicinity of equilibrium point. To reach global stability, a nonlinear controller is demanded.

Active control and synchronization chaotic satellite via the geomagnetic Lorentz force

NASA Astrophysics Data System (ADS)

Abdel-Aziz, Yehia

2016-07-01

The use of geomagnetic Lorentz force is considered in this paper for the purpose of satellite attitude control. A satellite with an electrostatic charge will interact with the Earth's magnetic field and experience the Lorentz force. An analytical attitude control and synchronization two identical chaotic satellite systems with different initial condition Master/ Slave are proposed to allows a charged satellite remains near the desired attitude. Asymptotic stability for the closed-loop system are investigated by means of Lyapunov stability theorem. The control feasibility depend on the charge requirement. Given a significantly and sufficiently accurate insertion, a charged satellite could maintains the desired attitude orientation without propellant. Simulations is performed to prove the efficacy of the proposed method.

Low drag attitude control for Skylab orbital lifetime extension

NASA Technical Reports Server (NTRS)

Glaese, J. R.; Kennel, H. F.

1981-01-01

In the fall of 1977 it was determined that Skylab had started to tumble and that the original orbit lifetime predictions were much too optimistic. A decision had to be made whether to accept an early uncontrolled reentry with its inherent risks or try to attempt to control Skylab to a lower drag attitude in the hope that there was enough time to develop a Teleoperator Retrieval System, bring it up on the Space Shuttle and then decide whether to boost Skylab to a higher longer life orbit or to reenter it in a controlled fashion. The end-on-velocity (EOVV) control method is documented, which was successfully applied for about half a year to keep Skylab in a low drag attitude with the aid of the control moment gyros and a minimal expenditure of attitude control gas.

Reviewing the effect of two methods of educational package and social inoculation on changing the attitudes towards domestic violence against women

PubMed Central

Boroumandfar, Khadijeh; Javaheri, Shabnam; Ehsanpour, Soheila; Abedi, Ahmad

2010-01-01

BACKGROUND: Domestic violence (DV) is a serious problem all over the world which had been extended to boundaries of countries, economical, cultural and racial classes. 10-69 percent of women are exposed to physical, sexual and emotional violence which has numerous physical and emotional consequences. Therefore, males’ attitude towards women is one of the strongest predicting factors of violence against women, so one of the ways to remove the violence against women is to change the men's attitude. Changing the attitude, in the basic stages of the marriage for couples who are not yet involved with marital misunderstandings, will probably influence their future relationships, therefore, the present study reviewed two attitude changing methods of educational package (EP) and social inoculation (SI) which were used to change the attitude among male volunteers participating in the premarital counseling classes. METHODS: This was a semi-experimental study aimed to determine the influence of two methods of supplying EP and SI on the change of attitude toward DV against women. The study subjects included male volunteers participating in Isfahan Molla Hadi Sabzevari Premarital Counseling Center, where the attitudes of 183 subjects were investigated primarily using simple sampling method. Ninety-nine subjects who had positive attitude toward DV were selected and then, randomly distributed into three 33-subject groups. The first was SI group, the second was EP supply group and the third was the control group. Data collection tool was an evaluating questionnaire of the attitude toward DV against women which consisted of two parts, demographic data and 34 attitude evaluating questions. Scientific validity was determined by content validity method and scientific reliability was determined using Cronbach's alpha. Analyzing the data was done using descriptive (frequency and mean), analytical statistical methods (paired-t, independent t-tests, ANOVA, Duncan, Kruskal-Wallis and chi-square) and SPSS software. RESULTS: Among 183 participants, 99 of them (54%) had a positive attitude with an average score of 46.5 and 84 of them (45%) with an average score of 29 had a negative attitude toward violence against women. Before the intervention, the highest violence attitude was in emotional, physical and sexual areas, respectively. After the intervention in the inoculation group, the highest attitude changes were in physical, sexual and emotional areas, respectively and in the EP group, in total the attitude changes score after the intervention was significant compared to prior to it, although changes were observed only in physical and sexual areas. In SI group, more attitude changes were occurred than that in EP group. In control group, the attitude score after the intervention had no significant change compared to it before. CONCLUSIONS: Although attitude change has no guaranty for changing the behavior, in order to change the behavior, changing the attitude is required, in which for violence against women, it is better to be started at the beginning of the marital relationship. The SI method has been successfully applied in psychology Sciences and the health programs, but the EP method is not an effective method on its own to change the attitude, so it is better to be accompanied by other methods like group discussion, etc. PMID:22069401

Position and attitude tracking control for a quadrotor UAV.

PubMed

Xiong, Jing-Jing; Zheng, En-Hui

2014-05-01

A synthesis control method is proposed to perform the position and attitude tracking control of the dynamical model of a small quadrotor unmanned aerial vehicle (UAV), where the dynamical model is underactuated, highly-coupled and nonlinear. Firstly, the dynamical model is divided into a fully actuated subsystem and an underactuated subsystem. Secondly, a controller of the fully actuated subsystem is designed through a novel robust terminal sliding mode control (TSMC) algorithm, which is utilized to guarantee all state variables converge to their desired values in short time, the convergence time is so small that the state variables are acted as time invariants in the underactuated subsystem, and, a controller of the underactuated subsystem is designed via sliding mode control (SMC), in addition, the stabilities of the subsystems are demonstrated by Lyapunov theory, respectively. Lastly, in order to demonstrate the robustness of the proposed control method, the aerodynamic forces and moments and air drag taken as external disturbances are taken into account, the obtained simulation results show that the synthesis control method has good performance in terms of position and attitude tracking when faced with external disturbances. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Attitude motion compensation for imager on Fengyun-4 geostationary meteorological satellite

NASA Astrophysics Data System (ADS)

Lyu, Wang; Dai, Shoulun; Dong, Yaohai; Shen, Yili; Song, Xiaozheng; Wang, Tianshu

2017-09-01

A compensation method is used in Chinese Fengyun-4 satellite to counteracting the line-of-sight influence by attitude motion during imaging. The method is acted on-board by adding the compensation amount to the instrument scanning control circuit. The mathematics simulation and the three-axis air-bearing test results show that the method works effectively.

Application of the concept of dynamic trim control and nonlinear system inverses to automatic control of a vertical attitude takeoff and landing aircraft

NASA Technical Reports Server (NTRS)

Smith, G. A.; Meyer, G.

1981-01-01

A full envelope automatic flight control system based on nonlinear inverse systems concepts has been applied to a vertical attitude takeoff and landing (VATOL) fighter aircraft. A new method for using an airborne digital aircraft model to perform the inversion of a nonlinear aircraft model is presented together with the results of a simulation study of the nonlinear inverse system concept for the vertical-attitude hover mode. The system response to maneuver commands in the vertical attitude was found to be excellent; and recovery from large initial offsets and large disturbances was found to be very satisfactory.

Magnetic dipole moment estimation and compensation for an accurate attitude control in nano-satellite missions

NASA Astrophysics Data System (ADS)

Inamori, Takaya; Sako, Nobutada; Nakasuka, Shinichi

2011-06-01

Nano-satellites provide space access to broader range of satellite developers and attract interests as an application of the space developments. These days several new nano-satellite missions are proposed with sophisticated objectives such as remote-sensing and observation of astronomical objects. In these advanced missions, some nano-satellites must meet strict attitude requirements for obtaining scientific data or images. For LEO nano-satellite, a magnetic attitude disturbance dominates over other environmental disturbances as a result of small moment of inertia, and this effect should be cancelled for a precise attitude control. This research focuses on how to cancel the magnetic disturbance in orbit. This paper presents a unique method to estimate and compensate the residual magnetic moment, which interacts with the geomagnetic field and causes the magnetic disturbance. An extended Kalman filter is used to estimate the magnetic disturbance. For more practical considerations of the magnetic disturbance compensation, this method has been examined in the PRISM (Pico-satellite for Remote-sensing and Innovative Space Missions). This method will be also used for a nano-astrometry satellite mission. This paper concludes that use of the magnetic disturbance estimation and compensation are useful for nano-satellites missions which require a high accurate attitude control.

The influence of the guided constructivist instructional model on attitudes toward secondary-level physics

NASA Astrophysics Data System (ADS)

Dallal, Kamel Salim

The effect of guided constructivism (bridging analogies) and expository instructional methods on the attitudes of students toward physics was investigated. A nonrandomize nonequivalent pretest-posttest control group quasi- experimental design was employed. The sample consisted of 127 eleventh-grade and twelfth-grade students from five selected classes from two private high schools in Beirut, Lebanon. Two intact classes were assigned to the control group and three classes to the experimental group. The experimental group was exposed to the bridging analogies instructional method, and the control group was taught using the traditional expository method. A Likert-type instrument, the Physics Attitude Index, was used to measure attitudes on four dimensions. The 40-item Physics Attitude Index (PAI) is a questionnaire using a five response scale. Performance in the assigned topics in physics, cognitive developmental levels, and gender were used as covariants and to examine interaction effects. The experimental groups had significantly higher means than the control groups on all criterion variables. A significant interaction was found between groups and performance levels in the following cases: (a) criterion variable of attitude toward physics; (b) views toward physics learning; and (c) enjoyment of physics. This result indicated that the low performing students among the experimental group had greater gain in attitude toward physics than the high performing students in same group. On the other hand, no interaction occurred between treatment groups and gender, which shows that in this study gender has no significant effect on attitude toward physics. Significant interactions between the treatment groups and cognitive levels were found on the criterion variable of beliefs about physics as a process of learning and enjoyment of physics. In both cases, the difference between the group means were widely different among students at the concrete and transitional levels, but narrowly different among students at the formal level.

Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices

NASA Technical Reports Server (NTRS)

Munday, Jeremy

2016-01-01

Solar sails offer an opportunity for a CubeSatscale, propellant-free spacecraft technology that enables long-term and long-distance missions not possible with traditional methods. Solar sails operate using the transfer of linear momentum from photons of sunlight reflected from the surface of the sail. To propel the spacecraft, no mechanically moving parts, thrusters, or propellant are needed. However, attitude control, or orientation, is still performed using traditional methods involving reaction wheels and propellant ejection, which severely limit mission lifetime. For example, the current state of the art solutions employed by upcoming missions couple solar sails with a state of the art propellant ejection gas system. Here, the use of the gas thruster has limited the lifetime of the mission. To solve the limited mission lifetime problem, the Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices project team is working on propellantless attitude control using thin layers of material, an optical film, electrically switchable from transparent to reflective. The technology is based on a polymer-dispersed liquid crystal (PDLC), which allows this switch upon application of a voltage. This technology removes the need for propellant, which reduces weight and cost while improving performance and lifetime.

The impact of group training about parenting styles on maternal attitudes toward parenting styles.

PubMed

Zandiyeh, Zahra; Zare, Elaheh; Hedayati, Batool

2015-01-01

Parenting style is one of the most important and effective factors in training and growth of children and adolescents and the method that parents communicate with their children is an effective factor on family contact models. The aim of this study was to determine the impact of group training about parenting styles on maternal attitudes that were admitted to Isfahan Imam Ali (AS) health care center in 2013. This was an experimental study, which was conducted on a random sample of 25 mothers referred to this health care center. They were divided into two groups (experimental and control). The experimental group received five sessions of group training, and the control group received a booklet about parenting styles. The used tool in this study was the Bamerind Parenting Style Questionnaire that was completed by the mothers before and after the intervention and finally, their obtained scores were compared with each other. The results of the present study showed that the mean score of attitude toward easy-going style in test group was less than the control group after intervention (P = 0.045). The mean score of attitude toward authoritative style in the experimental group was less than control group after intervention (P = 0.037) and the mean score of attitude toward authoritative style in the experimental group was more than the control group after intervention (P = 0.011). Group training can be an appropriate method in changing maternal attitudes toward parenting styles.

Touchless attitude correction for satellite with constant magnetic moment

NASA Astrophysics Data System (ADS)

Ao, Hou-jun; Yang, Le-ping; Zhu, Yan-wei; Zhang, Yuan-wen; Huang, Huan

2017-09-01

Rescue of satellite with attitude fault is of great value. Satellite with improper injection attitude may lose contact with ground as the antenna points to the wrong direction, or encounter energy problems as solar arrays are not facing the sun. Improper uploaded command may set the attitude out of control, exemplified by Japanese Hitomi spacecraft. In engineering practice, traditional physical contact approaches have been applied, yet with a potential risk of collision and a lack of versatility since the mechanical systems are mission-specific. This paper puts forward a touchless attitude correction approach, in which three satellites are considered, one having constant dipole and two having magnetic coils to control attitude of the first. Particular correction configurations are designed and analyzed to maintain the target's orbit during the attitude correction process. A reference coordinate system is introduced to simplify the control process and avoid the singular value problem of Euler angles. Based on the spherical triangle basic relations, the accurate varying geomagnetic field is considered in the attitude dynamic mode. Sliding mode control method is utilized to design the correction law. Finally, numerical simulation is conducted to verify the theoretical derivation. It can be safely concluded that the no-contact attitude correction approach for the satellite with uniaxial constant magnetic moment is feasible and potentially applicable to on-orbit operations.

Effects of the Integrated Online Advance Organizer Teaching Materials on Students' Science Achievement and Attitude

NASA Astrophysics Data System (ADS)

Korur, Fikret; Toker, Sacip; Eryılmaz, Ali

2016-08-01

This two-group quasi-experimental study investigated the effects of the Online Advance Organizer Concept Teaching Material (ONACOM) integrated with inquiry teaching and expository teaching methods. Grade 7 students' posttest performances on the light unit achievement and light unit attitude tests controlled for gender, previous semester science grade, and pretest scores were analyzed. No significant treatment effects were found between the inquiry and expository approaches. However, both groups demonstrated significant pretest-posttest gains in achievement and attitude. Independent from the method used, ONACOM was judged effective in both groups as students demonstrated increased achievement and attitude scores. ONACOM has a social and semantic network-aided infrastructure that can be adapted to both methods to increase students' achievement and improve their attitude.

Attitude tracking control of flexible spacecraft with large amplitude slosh

NASA Astrophysics Data System (ADS)

Deng, Mingle; Yue, Baozeng

2017-12-01

This paper is focused on attitude tracking control of a spacecraft that is equipped with flexible appendage and partially filled liquid propellant tank. The large amplitude liquid slosh is included by using a moving pulsating ball model that is further improved to estimate the settling location of liquid in microgravity or a zero-g environment. The flexible appendage is modelled as a three-dimensional Bernoulli-Euler beam, and the assumed modal method is employed. A hybrid controller that combines sliding mode control with an adaptive algorithm is designed for spacecraft to perform attitude tracking. The proposed controller has proved to be asymptotically stable. A nonlinear model for the overall coupled system including spacecraft attitude dynamics, liquid slosh, structural vibration and control action is established. Numerical simulation results are presented to show the dynamic behaviors of the coupled system and to verify the effectiveness of the control approach when the spacecraft undergoes the disturbance produced by large amplitude slosh and appendage vibration. Lastly, the designed adaptive algorithm is found to be effective to improve the precision of attitude tracking.

Orbit-attitude coupled motion around small bodies: Sun-synchronous orbits with Sun-tracking attitude motion

NASA Astrophysics Data System (ADS)

Kikuchi, Shota; Howell, Kathleen C.; Tsuda, Yuichi; Kawaguchi, Jun'ichiro

2017-11-01

The motion of a spacecraft in proximity to a small body is significantly perturbed due to its irregular gravity field and solar radiation pressure. In such a strongly perturbed environment, the coupling effect of the orbital and attitude motions exerts a large influence that cannot be neglected. However, natural orbit-attitude coupled dynamics around small bodies that are stationary in both orbital and attitude motions have yet to be observed. The present study therefore investigates natural coupled motion that involves both a Sun-synchronous orbit and Sun-tracking attitude motion. This orbit-attitude coupled motion enables a spacecraft to maintain its orbital geometry and attitude state with respect to the Sun without requiring active control. Therefore, the proposed method can reduce the use of an orbit and attitude control system. This paper first presents analytical conditions to achieve Sun-synchronous orbits and Sun-tracking attitude motion. These analytical solutions are then numerically propagated based on non-linear coupled orbit-attitude equations of motion. Consequently, the possibility of implementing Sun-synchronous orbits with Sun-tracking attitude motion is demonstrated.

Crew exploration vehicle (CEV) attitude control using a neural-immunology/memory network

NASA Astrophysics Data System (ADS)

Weng, Liguo; Xia, Min; Wang, Wei; Liu, Qingshan

2015-01-01

This paper addresses the problem of the crew exploration vehicle (CEV) attitude control. CEVs are NASA's next-generation human spaceflight vehicles, and they use reaction control system (RCS) jet engines for attitude adjustment, which calls for control algorithms for firing the small propulsion engines mounted on vehicles. In this work, the resultant CEV dynamics combines both actuation and attitude dynamics. Therefore, it is highly nonlinear and even coupled with significant uncertainties. To cope with this situation, a neural-immunology/memory network is proposed. It is inspired by the human memory and immune systems. The control network does not rely on precise system dynamics information. Furthermore, the overall control scheme has a simple structure and demands much less computation as compared with most existing methods, making it attractive for real-time implementation. The effectiveness of this approach is also verified via simulation.

Steering Law Controlling the Constant Speeds of Control Moment Gyros

NASA Astrophysics Data System (ADS)

KOYASAKO, Y.; TAKAHASHI, M.

2016-09-01

To enable the agile control of satellites, using control moment gyros (CMGs) has become increasingly necessary because of their ability to generate large amounts of torque. However, CMGs have a singularity problem whereby the torque by the CMGs degenerates from three dimensions to two dimensions, affecting spacecraft attitude control performance. This study proposes a new steering control law for CMGs by controlling the constant speed of a CMG. The proposed method enables agile attitude changes, according to the required task, by managing the total angular momentum of the CMGs by considering the distance to external singularities. In the proposed method, the total angular momentum is biased in a specific direction and the angular momentum envelope is extended. The design method can increase the net angular momentum of CMGs which can be exchanged with the satellite. The effectiveness of the proposed method is demonstrated by numerical simulations.

Fast spacecraft adaptive attitude tracking control through immersion and invariance design

NASA Astrophysics Data System (ADS)

Wen, Haowei; Yue, Xiaokui; Li, Peng; Yuan, Jianping

2017-10-01

This paper presents a novel non-certainty-equivalence adaptive control method for the attitude tracking control problem of spacecraft with inertia uncertainties. The proposed immersion and invariance (I&I) based adaptation law provides a more direct and flexible approach to circumvent the limitations of the basic I&I method without employing any filter signal. By virtue of the adaptation high-gain equivalence property derived from the proposed adaptive method, the closed-loop adaptive system with a low adaptation gain could recover the high adaptation gain performance of the filter-based I&I method, and the resulting control torque demands during the initial transient has been significantly reduced. A special feature of this method is that the convergence of the parameter estimation error has been observably improved by utilizing an adaptation gain matrix instead of a single adaptation gain value. Numerical simulations are presented to highlight the various benefits of the proposed method compared with the certainty-equivalence-based control method and filter-based I&I control schemes.

Effectiveness of Case-Based Learning Instruction on Epistemological Beliefs and Attitudes Toward Chemistry

NASA Astrophysics Data System (ADS)

Çam, Aylin; Geban, Ömer

2011-02-01

The purpose of the study was to investigate the effectiveness of case-based learning instruction over traditionally designed chemistry instruction on eleventh grade students' epistemological beliefs and their attitudes toward chemistry as a school subject. The subjects of this study consisted of 63 eleventh grade students from two intact classes of an urban high school instructed with same teacher. Each teaching method was randomly assigned to one class. The experimental group received case-based learning and the control group received traditional instruction. At the experimental group, life cases were presented with small group format; at the control group, lecturing and discussion was carried out. The results showed that there was a significant difference between the experimental and control group with respect to their epistemological beliefs and attitudes toward chemistry as a school subject in favor of case-based learning method group. Thus, case base learning is helpful for development of students' epistemological beliefs and attitudes toward chemistry.

Predictive momentum management for the Space Station

NASA Technical Reports Server (NTRS)

Hatis, P. D.

1986-01-01

Space station control moment gyro momentum management is addressed by posing a deterministic optimization problem with a performance index that includes station external torque loading, gyro control torque demand, and excursions from desired reference attitudes. It is shown that a simple analytic desired attitude solution exists for all axes with pitch prescription decoupled, but roll and yaw coupled. Continuous gyro desaturation is shown to fit neatly into the scheme. Example results for pitch axis control of the NASA power tower Space Station are shown based on predictive attitude prescription. Control effector loading is shown to be reduced by this method when compared to more conventional momentum management techniques.

Novel approach to improve the attitude update rate of a star tracker.

PubMed

Zhang, Shuo; Xing, Fei; Sun, Ting; You, Zheng; Wei, Minsong

2018-03-05

The star tracker is widely used in attitude control systems of spacecraft for attitude measurement. The attitude update rate of a star tracker is important to guarantee the attitude control performance. In this paper, we propose a novel approach to improve the attitude update rate of a star tracker. The electronic Rolling Shutter (RS) imaging mode of the complementary metal-oxide semiconductor (CMOS) image sensor in the star tracker is applied to acquire star images in which the star spots are exposed with row-to-row time offsets, thereby reflecting the rotation of star tracker at different times. The attitude estimation method with a single star spot is developed to realize the multiple attitude updates by a star image, so as to reach a high update rate. The simulation and experiment are performed to verify the proposed approaches. The test results demonstrate that the proposed approach is effective and the attitude update rate of a star tracker is increased significantly.

A Control Concept for Large Flexible Spacecraft Using Order Reduction Techniques

NASA Technical Reports Server (NTRS)

Thieme, G.; Roth, H.

1985-01-01

Results found during the investigation of control problems of large flexible spacecraft are given. A triple plate configuration of such a spacecraft is defined and studied. The model is defined by modal data derived from infinite element modeling. The order reduction method applied is briefly described. An attitude control concept with low and high authority control has been developed to design an attitude controller for the reduced model. The stability and response of the original system together with the reduced controller is analyzed.

The Effect of Constructivist Instruction on Prospective Teachers' Attitudes toward Human Rights Education

ERIC Educational Resources Information Center

Gundogdu, Kerim

2010-01-01

Introduction: This study investigates the effect of employing constructivist methods and materials on the attitudes of prospective teachers' (psychological counseling students) toward human rights education. Method: The research employed a quasi-experimental pre test-post test control group design. The experimental group, consisted of 23 male and…

Model predictive and reallocation problem for CubeSat fault recovery and attitude control

NASA Astrophysics Data System (ADS)

Franchi, Loris; Feruglio, Lorenzo; Mozzillo, Raffaele; Corpino, Sabrina

2018-01-01

In recent years, thanks to the increase of the know-how on machine-learning techniques and the advance of the computational capabilities of on-board processing, expensive computing algorithms, such as Model Predictive Control, have begun to spread in space applications even on small on-board processor. The paper presents an algorithm for an optimal fault recovery of a 3U CubeSat, developed in MathWorks Matlab & Simulink environment. This algorithm involves optimization techniques aiming at obtaining the optimal recovery solution, and involves a Model Predictive Control approach for the attitude control. The simulated system is a CubeSat in Low Earth Orbit: the attitude control is performed with three magnetic torquers and a single reaction wheel. The simulation neglects the errors in the attitude determination of the satellite, and focuses on the recovery approach and control method. The optimal recovery approach takes advantage of the properties of magnetic actuation, which gives the possibility of the redistribution of the control action when a fault occurs on a single magnetic torquer, even in absence of redundant actuators. In addition, the paper presents the results of the implementation of Model Predictive approach to control the attitude of the satellite.

Application of experiential learning model using simple physical kit to increase attitude toward physics student senior high school in fluid

NASA Astrophysics Data System (ADS)

Johari, A. H.; Muslim

2018-05-01

Experiential learning model using simple physics kit has been implemented to get a picture of improving attitude toward physics senior high school students on Fluid. This study aims to obtain a description of the increase attitudes toward physics senior high school students. The research method used was quasi experiment with non-equivalent pretest -posttest control group design. Two class of tenth grade were involved in this research 28, 26 students respectively experiment class and control class. Increased Attitude toward physics of senior high school students is calculated using an attitude scale consisting of 18 questions. Based on the experimental class test average of 86.5% with the criteria of almost all students there is an increase and in the control class of 53.75% with the criteria of half students. This result shows that the influence of experiential learning model using simple physics kit can improve attitude toward physics compared to experiential learning without using simple physics kit.

Intention to Seek Mental Health Treatment for Adolescent Girls: Comparison of Predictors in Mothers and Daughters

PubMed Central

Logsdon, M. Cynthia; Pinto, Melissa D.; LaJoie, A. Scott; Hertweck, Paige; Lynch, Tania; Flamini, Laura

2013-01-01

PROBLEM To examine predictors of intention to seek mental health treatment for adolescent girls in mothers and daughters. METHODS In this cross-sectional study, mothers and adolescent daughters (n = 71) completed measures of behavioral attitudes, subjective norms, perceived behavioral control, and intention to seek mental health treatment for the adolescent daughter. FINDINGS Behavioral attitude and perceived behavioral control predicted intention to seek mental health treatment among mothers. Behavioral attitude predicted intention among daughters. There were no associations between mothers and daughters on study variables. CONCLUSIONS To promote shared decision making and engagement in mental health treatment, clinicians may target interventions to the mother’s perceived behavioral control and behavioral attitudes of daughters and mothers. Based upon study results, clinicians should promote shared decision making and concordance between mothers and daughters on attitudes toward mental health treatment. PMID:24180603

Spacecraft attitude control using neuro-fuzzy approximation of the optimal controllers

NASA Astrophysics Data System (ADS)

Kim, Sung-Woo; Park, Sang-Young; Park, Chandeok

2016-01-01

In this study, a neuro-fuzzy controller (NFC) was developed for spacecraft attitude control to mitigate large computational load of the state-dependent Riccati equation (SDRE) controller. The NFC was developed by training a neuro-fuzzy network to approximate the SDRE controller. The stability of the NFC was numerically verified using a Lyapunov-based method, and the performance of the controller was analyzed in terms of approximation ability, steady-state error, cost, and execution time. The simulations and test results indicate that the developed NFC efficiently approximates the SDRE controller, with asymptotic stability in a bounded region of angular velocity encompassing the operational range of rapid-attitude maneuvers. In addition, it was shown that an approximated optimal feedback controller can be designed successfully through neuro-fuzzy approximation of the optimal open-loop controller.

Approaching control for tethered space robot based on disturbance observer using super twisting law

NASA Astrophysics Data System (ADS)

Hu, Yongxin; Huang, Panfeng; Meng, Zhongjie; Wang, Dongke; Lu, Yingbo

2018-05-01

Approaching control is a key mission for the tethered space robot to perform the task of removing space debris. But the uncertainties of the TSR such as the change of model parameter have an important effect on the approaching mission. Considering the space tether and the attitude of the gripper, the dynamic model of the TSR is derived using Lagrange method. Then a disturbance observer is designed to estimate the uncertainty based on STW control method. Using the disturbance observer, a controller is designed, and the performance is compared with the dynamic inverse controller which turns out that the proposed controller performs better. Numerical simulation validates the feasibility of the proposed controller on the position and attitude tracking of the TSR.

Diagnosis before treatment: Identifying dairy farmers' determinants for the adoption of sustainable practices in gastrointestinal nematode control.

PubMed

Vande Velde, F; Claerebout, E; Cauberghe, V; Hudders, L; Van Loo, H; Vercruysse, J; Charlier, J

2015-09-15

Anthelmintic resistance is emerging in dairy cattle and this can result in a lack of effective control and production losses. Therefore, sustainable control strategies, such as targeted treatments (TT) and targeted selected treatments (TST), should be adopted by the industry. TT and TST approaches require the use of diagnostic methods to take informed treatment decisions. To understand the factors affecting the farmers' intention to adopt diagnostic methods before implementing anthelmintic drugs ('adoption intention'), a cross-sectional survey was carried out in dairy farms in Belgium (Flanders). A framework was constructed to predict adoption intentions based on two fundamental theories in the field of behavioural psychology and health psychology: the Theory of Planned Behaviour and the Health Belief Model. In the tested model, adoption intentions were predicted based on attitudes towards anthelminthics, attitudes towards diagnostic methods, subjective norms, behavioural control and perceived risk. Structural equation modelling was used for analyses. The model fitted the data well and explained 46% of the variance in adoption intention of diagnostics. The factors 'attitude towards diagnostic methods' and 'subjective norm'; i.e. the influence of significant others, had the strongest, positive influence on adoption intention of diagnostic methods. 'Perceived behavioural control' had a weak, positive effect on intention. Further, 'attitude towards the use of anthelmintic drugs' had a negative effect on adoption intention of the diagnostic methods. This implicates an effect of current behaviour on future adoption, which should be considered in future research. Factors measuring risk perception of anthelmintic resistance; perceived severity and perceived susceptibility, had no effect on the adoption intention of diagnostic methods. The threat of anthelmintic resistance is perceived to be low for dairy herds. The study further did not find any differences in the effects of the predictors for young stock and adult dairy cows. The results of this study can be used to develop communication strategies to advertise sustainable nematode control on dairy farms. Copyright © 2015 Elsevier B.V. All rights reserved.

GOES I/M image navigation and registration

NASA Technical Reports Server (NTRS)

Fiorello, J. L., Jr.; Oh, I. H.; Kelly, K. A.; Ranne, L.

1989-01-01

Image Navigation and Registration (INR) is the system that will be used on future Geostationary Operational Environmental Satellite (GOES) missions to locate and register radiometric imagery data. It consists of a semiclosed loop system with a ground-based segment that generates coefficients to perform image motion compensation (IMC). The IMC coefficients are uplinked to the satellite-based segment, where they are used to adjust the displacement of the imagery data due to movement of the imaging instrument line-of-sight. The flight dynamics aspects of the INR system is discussed in terms of the attitude and orbit determination, attitude pointing, and attitude and orbit control needed to perform INR. The modeling used in the determination of orbit and attitude is discussed, along with the method of on-orbit control used in the INR system, and various factors that affect stability. Also discussed are potential error sources inherent in the INR system and the operational methods of compensating for these errors.

Mathematical Critical Thinking and Curiosity Attitude in Problem Based Learning and Cognitive Conflict Strategy: A Study in Number Theory Course

ERIC Educational Resources Information Center

Zetriuslita; Wahyudin; Jarnawi

2017-01-01

This research aims to describe and analyze result of applying Problem-Based Learning and Cognitive Conflict Strategy (PBLCCS) in increasing students' Mathematical Critical Thinking (MCT) ability and Mathematical Curiosity Attitude (MCA). Adopting a quasi-experimental method with pretest-posttest control group design and using mixed method with…

Spacecraft attitude and velocity control system

NASA Technical Reports Server (NTRS)

Paluszek, Michael A. (Inventor); Piper, Jr., George E. (Inventor)

1992-01-01

A spacecraft attitude and/or velocity control system includes a controller which responds to at least attitude errors to produce command signals representing a force vector F and a torque vector T, each having three orthogonal components, which represent the forces and torques which are to be generated by the thrusters. The thrusters may include magnetic torquer or reaction wheels. Six difference equations are generated, three having the form ##EQU1## where a.sub.j is the maximum torque which the j.sup.th thruster can produce, b.sub.j is the maximum force which the j.sup.th thruster can produce, and .alpha..sub.j is a variable representing the throttling factor of the j.sup.th thruster, which may range from zero to unity. The six equations are summed to produce a single scalar equation relating variables .alpha..sub.j to a performance index Z: ##EQU2## Those values of .alpha. which maximize the value of Z are determined by a method for solving linear equations, such as a linear programming method. The Simplex method may be used. The values of .alpha..sub.j are applied to control the corresponding thrusters.

Women's attitudes towards mechanisms of action of birth control methods: a cross-sectional study in five European countries.

PubMed

Lopez-del Burgo, Cristina; Mikolajczyk, Rafael T; Osorio, Alfonso; Errasti, Tania; de Irala, Jokin

2013-11-01

To assess women's attitudes towards the mechanisms of action of birth control methods. When addressing women's knowledge of and attitudes towards birth control methods, researchers frequently focus on side effects, effectiveness or correct use. Women's opinions about mechanisms of action have been much less investigated, and research is usually concentrated on the EC pill. Cross-sectional study. Women, aged 18-49, from Germany, France, the UK, Sweden and Romania were randomly selected (n = 1137). They were asked whether they would use a method that may work after fertilisation or after implantation and whether they would continue using it after learning it may have such effects. Logistic regression was performed to evaluate the influence of certain characteristics on women's attitudes. Almost half of women in Romania and Germany would not use methods with postfertilisation effects, while the lowest percentages were found in Sweden and in France. Regarding methods with postimplantation effects, higher percentages were found in all the countries. Highly educated women and those using a highly effective method were more likely to use methods with postfertilisation effects. On the contrary, married women, those who stated that human life begins at fertilisation and women with middle/high religiosity were less likely to consider using methods that may act after fertilisation. One-third of European women reported that they would not consider using a method that may have postfertilisation effects. Given that postfertilisation effects may not be acceptable to some women, informing them of which methods may have these effects is essential to obtaining complete informed consent and to promoting women's autonomy. © 2013 John Wiley & Sons Ltd.

Torque equilibrium attitude control for Skylab reentry

NASA Technical Reports Server (NTRS)

Glaese, J. R.; Kennel, H. F.

1979-01-01

All the available torque equilibrium attitudes (most were useless from the standpoint of lack of electrical power) and the equilibrium seeking method are presented, as well as the actual successful application during the 3 weeks prior to Skylab reentry.

Trajectory tracking control for underactuated stratospheric airship

NASA Astrophysics Data System (ADS)

Zheng, Zewei; Huo, Wei; Wu, Zhe

2012-10-01

Stratospheric airship is a new kind of aerospace system which has attracted worldwide developing interests for its broad application prospects. Based on the trajectory linearization control (TLC) theory, a novel trajectory tracking control method for an underactuated stratospheric airship is presented in this paper. Firstly, the TLC theory is described sketchily, and the dynamic model of the stratospheric airship is introduced with kinematics and dynamics equations. Then, the trajectory tracking control strategy is deduced in detail. The designed control system possesses a cascaded structure which consists of desired attitude calculation, position control loop and attitude control loop. Two sub-loops are designed for the position and attitude control loops, respectively, including the kinematics control loop and dynamics control loop. Stability analysis shows that the controlled closed-loop system is exponentially stable. Finally, simulation results for the stratospheric airship to track typical trajectories are illustrated to verify effectiveness of the proposed approach.

State estimation for autopilot control of small unmanned aerial vehicles in windy conditions

NASA Astrophysics Data System (ADS)

Poorman, David Paul

The use of small unmanned aerial vehicles (UAVs) both in the military and civil realms is growing. This is largely due to the proliferation of inexpensive sensors and the increase in capability of small computers that has stemmed from the personal electronic device market. Methods for performing accurate state estimation for large scale aircraft have been well known and understood for decades, which usually involve a complex array of expensive high accuracy sensors. Performing accurate state estimation for small unmanned aircraft is a newer area of study and often involves adapting known state estimation methods to small UAVs. State estimation for small UAVs can be more difficult than state estimation for larger UAVs due to small UAVs employing limited sensor suites due to cost, and the fact that small UAVs are more susceptible to wind than large aircraft. The purpose of this research is to evaluate the ability of existing methods of state estimation for small UAVs to accurately capture the states of the aircraft that are necessary for autopilot control of the aircraft in a Dryden wind field. The research begins by showing which aircraft states are necessary for autopilot control in Dryden wind. Then two state estimation methods that employ only accelerometer, gyro, and GPS measurements are introduced. The first method uses assumptions on aircraft motion to directly solve for attitude information and smooth GPS data, while the second method integrates sensor data to propagate estimates between GPS measurements and then corrects those estimates with GPS information. The performance of both methods is analyzed with and without Dryden wind, in straight and level flight, in a coordinated turn, and in a wings level ascent. It is shown that in zero wind, the first method produces significant steady state attitude errors in both a coordinated turn and in a wings level ascent. In Dryden wind, it produces large noise on the estimates for its attitude states, and has a non-zero mean error that increases when gyro bias is increased. The second method is shown to not exhibit any steady state error in the tested scenarios that is inherent to its design. The second method can correct for attitude errors that arise from both integration error and gyro bias states, but it suffers from lack of attitude error observability. The attitude errors are shown to be more observable in wind, but increased integration error in wind outweighs the increase in attitude corrections that such increased observability brings, resulting in larger attitude errors in wind. Overall, this work highlights many technical deficiencies of both of these methods of state estimation that could be improved upon in the future to enhance state estimation for small UAVs in windy conditions.

Hierarchical control of ride height system for electronically controlled air suspension based on variable structure and fuzzy control theory

NASA Astrophysics Data System (ADS)

Xu, Xing; Zhou, Kongkang; Zou, Nannan; Jiang, Hong; Cui, Xiaoli

2015-09-01

The current research of air suspension mainly focuses on the characteristics and design of the air spring. In fact, electronically controlled air suspension (ECAS) has excellent performance in flexible height adjustment during different driving conditions. However, the nonlinearity of the ride height adjusting system and the uneven distribution of payload affect the control accuracy of ride height and the body attitude. Firstly, the three-point measurement system of three height sensors is used to establish the mathematical model of the ride height adjusting system. The decentralized control of ride height and the centralized control of body attitude are presented to design the ride height control system for ECAS. The exact feedback linearization method is adopted for the nonlinear mathematical model of the ride height system. Secondly, according to the hierarchical control theory, the variable structure control (VSC) technique is used to design a controller that is able to adjust the ride height for the quarter-vehicle anywhere, and each quarter-vehicle height control system is independent. Meanwhile, the three-point height signals obtained by three height sensors are tracked to calculate the body pitch and roll attitude over time, and then by calculating the deviation of pitch and roll and its rates, the height control correction is reassigned based on the fuzzy algorithm. Finally, to verify the effectiveness and performance of the proposed combined control strategy, a validating test of ride height control system with and without road disturbance is carried out. Testing results show that the height adjusting time of both lifting and lowering is over 5 s, and the pitch angle and the roll angle of body attitude are less than 0.15°. This research proposes a hierarchical control method that can guarantee the attitude stability, as well as satisfy the ride height tracking system.

The Effect on the 8th Grade Students' Attitude towards Statistics of Project Based Learning

ERIC Educational Resources Information Center

Koparan, Timur; Güven, Bülent

2014-01-01

This study investigates the effect of the project based learning approach on 8th grade students' attitude towards statistics. With this aim, an attitude scale towards statistics was developed. Quasi-experimental research model was used in this study. Following this model in the control group the traditional method was applied to teach statistics…

Attitude Dynamics and Control of Solar Sails

NASA Astrophysics Data System (ADS)

Sperber, Evan

Solar sails are space vehicles that rely on solar radiation pressure in order to generate forces for thrust and attitude control torques. They exhibit characteristics such as large moments of inertia, fragility of various system components, and long mission durations that make attitude control a particularly difficult engineering problem. Thrust vector control (TVC) is a family of sailcraft attitude control techniques that is on a short list of strategies thought to be suitable for the primary attitude control of solar sails. Every sailcraft TVC device functions by manipulating the relative locations of the composite mass center (cm) of the sailcraft and the center of pressure (cp) of at least one of its reflectors. Relative displacement of these two points results in body torques that can be used to steer the sailcraft. This dissertation presents a strategy for the large-angle reorientation of a sailcraft using TVC. Two forms of TVC, namely the panel and ballast mass translation methods are well represented in the literature, while rigorous studies regarding a third form, gimballed mass rotation, are conspicuously absent. The gimballed mass method is physically realized by placing a ballast mass, commonly the sailcraft's scientific payload, at the tip of a gimballed boom that has its base fixed at some point on the sailcraft. A TVC algorithm will then strategically manipulate the payload boom's gimbal angles, thereby changing the projection of the sailcraft cm in the plane of the sail. This research demonstrates effective three-axis attitude control of a model sailcraft using numerical simulation of its nonlinear equations of motion. The particular TVC algorithm developed herein involves two phases---the first phase selects appropriate gimbal rates with the objective that the sailcraft be placed in the neighborhood of its target orientation. It was discovered, however that concomitantly minimizing attitude error as well as residual body rate was not possible using soley this method. By solving the one-dimensional Euler's equation, a single gimbal angle can be found that will cause simultaneous convergence of both these quantities to their respective target values. The second phase of control consists of calculating such an angle, and then setting and maintaining this configuration until the maneuver is completed. iiOnce the validity of the approach is confirmed via simulation for a model sailcraft, it is demonstrated that three-axis attitude control can be performed using this approach by executing a sequence of maneuvers about principal axes. The algorithm is implemented directly inline with the nonlinear equations of motion and simulations are conducted for sailcraft of various sizes that are representative of the dimensions proposed in the literature for future missions.

Precision tethered satellite attitude control. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Kline-Schoder, Robert J.

1990-01-01

Tethered spacecraft possess unique dynamic characteristics which make them advantageous for certain classes of experiments. One use for which tethers are particularly well suited is to provide an isolated platform for spaceborne observatories. The advantages of tethering a pointing platform 1 or 2 km from a space shuttle or space station are that, compared to placing the observatory on the parent spacecraft, vibrational disturbances are attenuated and contamination is eliminated. In practice, all satellites have some requirement on the attitude control of the spacecraft, and tethered satellites are no exception. It has previously been shown that conventional means of performing attitude control for tethered satellites are insufficient for any mission with pointing requirements more stringent than about 1 deg. This is due mainly to the relatively large force applied by the tether to the spacecraft. A particularly effective method of implementing attitude control for tethered satellites is to use this tether tension force to generate control torques by moving the tether attach point relative to the subsatellite center of mass. A demonstration of this attitude control technique on an astrophysical pointing platform has been proposed for a space shuttle flight test project and is referred to as the Kinetic Isolation Tether Experiment (KITE).

Attitude control/momentum management and payload pointing in advanced space vehicles

NASA Technical Reports Server (NTRS)

Parlos, Alexander G.; Jayasuriya, Suhada

1990-01-01

The design and evaluation of an attitude control/momentum management system for highly asymmetric spacecraft configurations are presented. The preliminary development and application of a nonlinear control system design methodology for tracking control of uncertain systems, such as spacecraft payload pointing systems are also presented. Control issues relevant to both linear and nonlinear rigid-body spacecraft dynamics are addressed, whereas any structural flexibilities are not taken into consideration. Results from the first task indicate that certain commonly used simplifications in the equations of motions result in unstable attitude control systems, when used for highly asymmetric spacecraft configurations. An approach is suggested circumventing this problem. Additionally, even though preliminary results from the second task are encouraging, the proposed nonlinear control system design method requires further investigation prior to its application and use as an effective payload pointing system design technique.

Effects of knowledge and internal locus of control in groups of health care workers judging likelihood of pathogen transfer.

PubMed

McLaughlin, Anne Collins; Walsh, Fran; Bryant, Michelle

2013-08-01

A study was conducted to measure the effects of attitudes and beliefs on the risk judgments of health care workers. Lack of hand hygiene compliance is a worldwide issue in health care, contributing to infections, fatalities, and increased health care costs. Human factors methods are a promising solution to the problem of compliance, although thus far, the concentration has been on process and engineering methods, such as the design of no-touch sinks. Factors internal to the health care worker, such as their attitudes and beliefs about hand hygiene, have received less attention. For this study, three groups of health care workers completed measures of attitudes, control beliefs, and hand hygiene knowledge. They then provided risk judgments of touching various surfaces via a factorial survey. Attitudes, knowledge, control beliefs, and surface type all predicted the risk judgments of the sample of health care workers, with differences between professional groups. Health care workers perceive less risk when touching surfaces,which may explain historically low rates of hand hygiene compliance after surface contact. Although more research is needed to directly connect risk judgments to failures of hand hygiene, the current results can inform interventions targeting the internal attitudes and beliefs of health care workers.

Research on flight stability performance of rotor aircraft based on visual servo control method

NASA Astrophysics Data System (ADS)

Yu, Yanan; Chen, Jing

2016-11-01

control method based on visual servo feedback is proposed, which is used to improve the attitude of a quad-rotor aircraft and to enhance its flight stability. Ground target images are obtained by a visual platform fixed on aircraft. Scale invariant feature transform (SIFT) algorism is used to extract image feature information. According to the image characteristic analysis, fast motion estimation is completed and used as an input signal of PID flight control system to realize real-time status adjustment in flight process. Imaging tests and simulation results show that the method proposed acts good performance in terms of flight stability compensation and attitude adjustment. The response speed and control precision meets the requirements of actual use, which is able to reduce or even eliminate the influence of environmental disturbance. So the method proposed has certain research value to solve the problem of aircraft's anti-disturbance.

Attractive manifold-based adaptive solar attitude control of satellites in elliptic orbits

NASA Astrophysics Data System (ADS)

Lee, Keum W.; Singh, Sahjendra N.

2011-01-01

The paper presents a novel noncertainty-equivalent adaptive (NCEA) control system for the pitch attitude control of satellites in elliptic orbits using solar radiation pressure (SRP). The satellite is equipped with two identical solar flaps to produce control moments. The adaptive law is based on the attractive manifold design using filtered signals for synthesis, which is a modification of the immersion and invariance (I&I) method. The control system has a modular controller-estimator structure and has separate tunable gains. A special feature of this NCEA law is that the trajectories of the satellite converge to a manifold in an extended state space, and the adaptive law recovers the performance of a deterministic controller. This recovery of performance cannot be obtained with certainty-equivalent adaptive (CEA) laws. Simulation results are presented which show that the NCEA law accomplishes precise attitude control of the satellite in an elliptic orbit, despite large parameter uncertainties.

Latent interaction effects in the theory of planned behaviour applied to quitting smoking.

PubMed

Hukkelberg, Silje Sommer; Hagtvet, Knut A; Kovac, Velibor Bobo

2014-02-01

This study applies three latent interaction models in the theory of planned behaviour (TPB; Ajzen, 1988, Attitudes, personality, and behavior. Homewood, IL: Dorsey Press; Ajzen, 1991, Organ. Behav. Hum. Decis. Process., 50, 179) to quitting smoking: (1) attitude × perceived behavioural control on intention; (2) subjective norms (SN) × attitude on intention; and (3) perceived behavioural control × intention on quitting behaviour. The data derive from a longitudinal Internet survey of 939 smokers aged 15-74 over a period of 4 months. Latent interaction effects were estimated using the double-mean-centred unconstrained approach (Lin et al., 2010, Struct. Equ. Modeling, 17, 374) in LISREL. Attitude × SN and attitude × perceived behavioural control both showed a significant interaction effect on intention. No significant interaction effect was found for perceived behavioural control × intention on quitting. The latent interaction approach is a useful method for investigating specific conditions between TPB components in the context of quitting behaviour. Theoretical and practical implications of the results are discussed. © 2013 The British Psychological Society.

Teamwork training with nursing and medical students: does the method matter? Results of an interinstitutional, interdisciplinary collaboration.

PubMed

Hobgood, Cherri; Sherwood, Gwen; Frush, Karen; Hollar, David; Maynard, Laura; Foster, Beverly; Sawning, Susan; Woodyard, Donald; Durham, Carol; Wright, Melanie; Taekman, Jeffrey

2010-12-01

The authors conducted a randomised controlled trial of four pedagogical methods commonly used to deliver teamwork training and measured the effects of each method on the acquisition of student teamwork knowledge, skills, and attitudes. The authors recruited 203 senior nursing students and 235 fourth-year medical students (total N = 438) from two major universities for a 1-day interdisciplinary teamwork training course. All participants received a didactic lecture and then were randomly assigned to one of four educational methods didactic (control), audience response didactic, role play and human patient simulation. Student performance was assessed for teamwork attitudes, knowledge and skills using: (a) a 36-item teamwork attitudes instrument (CHIRP), (b) a 12-item teamwork knowledge test, (c) a 10-item standardised patient (SP) evaluation of student teamwork skills performance and (d) a 20-item modification of items from the Mayo High Performance Teamwork Scale (MHPTS). All four cohorts demonstrated an improvement in attitudes (F(1,370) = 48.7, p = 0.001) and knowledge (F(1,353) = 87.3, p = 0.001) pre- to post-test. No educational modality appeared superior for attitude (F(3,370) = 0.325, p = 0.808) or knowledge (F(3,353) = 0.382, p = 0.766) acquisition. No modality demonstrated a significant change in teamwork skills (F(3,18) = 2.12, p = 0.134). Each of the four modalities demonstrated significantly improved teamwork knowledge and attitudes, but no modality was demonstrated to be superior. Institutions should feel free to utilise educational modalities, which are best supported by their resources to deliver interdisciplinary teamwork training.

Application of media literacy education for changing attitudes about self-medication of slimming supplements

PubMed Central

Solhi, Mahnaz; Jormand, Hanieh; Gohari, Mahmood Reza

2017-01-01

Background: Self-medication of slimming supplements has increased, and media advertising has a role in this. The present study aimed at determining the effect of media literacy educational intervention on attitudes about self-medication of slimming supplements among the female students at dormitories of Iran University of Medical Sciences. Methods: In this quasi-experimental study with a control group, 98 students were selected by multistage cluster sampling method and were randomly divided into 2 equal groups of test and control. The data collecting instrument was a researcher-made questionnaire about media literacy and attitude on self-medication of slimming pills. Based on the results obtained from the early completion of the questionnaires, an appropriate educational intervention was designed and implemented. Data were analyzed 1 and 3 months after the intervention using the following statistical methods: repeated measurements, Friedman test, Chi square, independent T-test and MannWhitney test. Results: Before the intervention, the mean scores of attitude and dimensions of media literacy were moderate in both groups, and there was no significant difference between them. However, positive correlations were observed among attitude and knowledge (r=0.99, p= 0.001), critical thinking (r= 0.61, p= 0.001), and analysis (r= 0.37, p= 0.009) in the experimental group. The mean scores of attitudes and dimensions of media literacy were found to be significant in both groups 1 and 3 months after the intervention (p<0.05). Conclusion: Media literacy education was effective in promoting a positive attitude about slimming supplements.

Six Degrees-of-Freedom Ascent Control for Small-Body Touch and Go

NASA Technical Reports Server (NTRS)

Blackmore, Lars James C.

2011-01-01

A document discusses a method of controlling touch and go (TAG) of a spacecraft to correct attitude, while ensuring a safe ascent. TAG is a concept whereby a spacecraft is in contact with the surface of a small body, such as a comet or asteroid, for a few seconds or less before ascending to a safe location away from the small body. The report describes a controller that corrects attitude and ensures that the spacecraft ascends to a safe state as quickly as possible. The approach allocates a certain amount of control authority to attitude control, and uses the rest to accelerate the spacecraft as quickly as possible in the ascent direction. The relative allocation to attitude and position is a parameter whose optimal value is determined using a ground software tool. This new approach makes use of the full control authority of the spacecraft to correct the errors imparted by the contact, and ascend as quickly as possible. This is in contrast to prior approaches, which do not optimize the ascent acceleration.

[Effects of an Individual Breast-feeding Promotion Program for Married Immigrant Women].

PubMed

Park, Mi Kyoung; Moon, So Hyun

2016-02-01

This study was designed to evaluate the effects of an individual breast-feeding promotion program to address breast-feeding knowledge, attitude, method and rate of practice for married immigrant women. A non-equivalent control group quasi-experimental design was used (experimental group=16, control group=17). The intervention consisted of 3 phases: (1) Within 2 hours of delivery - individual breast-feeding training through video/verbal/practical training education and demonstration (2) After 1~2 days - group training using video, model doll, and breast models (3) After 7 days - family visit, counseling, retraining and reinforcement training. The data were analyzed using non-parametric tests with the SPSS program. Married immigrant women who participated in the individual breast-feeding program scored high in knowledge, attitude, method and rate of practice compared to the control group. The results indicate that the individual breast-feeding program is very effective in increasing breast-feeding knowledge, attitude, method and rate of practicing breast feeding for married immigrant women. So, nurses are encouraged to aggressively utilize individual breast-feeding programs to help married immigrant women, who are exposed to vulnerability due to various situations.

Didactic satellite based on Android platform for space operation demonstration and development

NASA Astrophysics Data System (ADS)

Ben Bahri, Omar; Besbes, Kamel

2018-03-01

Space technology plays a pivotal role in society development. It offers new methods for telemetry, monitoring and control. However, this sector requires training, research and skills development but the lack of instruments, materials and budgets affects the ambiguity to understand satellite technology. The objective of this paper is to describe a demonstration prototype of a smart phone device for space operations study. Therefore, the first task was carried out to give a demonstration for spatial imagery and attitude determination missions through a wireless communication. The smart phone's Bluetooth was used to achieve this goal inclusive of a new method to enable real time transmission. In addition, an algorithm around a quaternion based Kalman filter was included in order to detect the reliability of the prototype's orientation. The second task was carried out to provide a demonstration for the attitude control mission using the smart phone's orientation sensor, including a new method for an autonomous guided mode. As a result, the acquisition platform showed real time measurement with good accuracy for orientation detection and image transmission. In addition, the prototype kept the balance during the demonstration based on the attitude control method.

Dynamically Stable Legged Locomotion.

DTIC Science & Technology

1983-01-27

sweeps the leg during stance, and the third places the foot during flight and controls body attitude during stance. Each of the three methods elucidates...secondary strategy has been to examine systems with springy legs, so that the role of resonant oscillatory leg behavior might be better understood. ’ The ...body attitude : I lopping _leit: ’ The control system rcgulate:; hopping height by manlil)Lulating hopping energy. The leg is springy, so hopping is a

Effectiveness of public deliberation methods for gathering input on issues in healthcare: Results from a randomized trial.

PubMed

Carman, Kristin L; Mallery, Coretta; Maurer, Maureen; Wang, Grace; Garfinkel, Steve; Yang, Manshu; Gilmore, Dierdre; Windham, Amy; Ginsburg, Marjorie; Sofaer, Shoshanna; Gold, Marthe; Pathak-Sen, Ela; Davies, Todd; Siegel, Joanna; Mangrum, Rikki; Fernandez, Jessica; Richmond, Jennifer; Fishkin, James; Siu Chao, Alice

2015-05-01

Public deliberation elicits informed perspectives on complex issues that are values-laden and lack technical solutions. This Deliberative Methods Demonstration examined the effectiveness of public deliberation for obtaining informed public input regarding the role of medical evidence in U.S. healthcare. We conducted a 5-arm randomized controlled trial, assigning participants to one of four deliberative methods or to a reading materials only (RMO) control group. The four deliberative methods reflected important differences in implementation, including length of the deliberative process and mode of interaction. The project convened 76 groups between August and November 2012 in four U.S. Chicago, IL; Sacramento, CA; Silver Spring, MD; and Durham, NC, capturing a sociodemographically diverse sample with specific attention to ensuring inclusion of Hispanic, African-American, and elderly participants. Of 1774 people recruited, 75% participated: 961 took part in a deliberative method and 377 participants comprised the RMO control group. To assess effectiveness of the deliberative methods overall and of individual methods, we evaluated whether mean pre-post changes on a knowledge and attitude survey were statistically different from the RMO control using ANCOVA. In addition, we calculated mean scores capturing participant views of the impact and value of deliberation. Participating in deliberation increased participants' knowledge of evidence and comparative effectiveness research and shifted participants' attitudes regarding the role of evidence in decision-making. When comparing each deliberative method to the RMO control group, all four deliberative methods resulted in statistically significant change on at least one knowledge or attitude measure. These findings were underscored by self-reports that the experience affected participants' opinions. Public deliberation offers unique potential for those seeking informed input on complex, values-laden topics affecting broad public constituencies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Distributed control of large space structures

NASA Technical Reports Server (NTRS)

Schaechter, D. B.

1981-01-01

Theoretical developments and the results of laboratory experiments are treated as they apply to active attitude and vibration control, as well as static shape control. Modern control theory was employed throughout as the method for obtaining estimation and control laws.

Knowledge, Attitude, Practice, and Status of Infection Control among Iranian Dentists and Dental Students: A Systematic Review

PubMed Central

Moradi Khanghahi, Behnam; Jamali, Zahra; Pournaghi Azar, Fatemeh; Naghavi Behzad, Mohammad; Azami-Aghdash, Saber

2013-01-01

Background and aims Infection control is an important issue in dentistry, and the dentists are primarily responsible for observing the relevant procedures. Therefore, the present study evaluated knowledge, attitude, practice, and status of infection control among Iranian dentists through systematic review of published results. Materials and methods In this systematic review, the required data was collected searching for keywords including infection, infection control, behavior, performance, practice, attitude, knowledge, dent*, prevention, Iran* and their Persian equivalents in PubMed, Science Direct, Iranmedex, SID, Medlib, and Magiran databases with a time limit of 1985 to 2012. Out of 698 articles, 15 completely related articles were finally considered and the rest were excluded due to lake of relev-ance to the study goals. The required data were extracted and summarized in an Extraction Table and were analyzed ma-nually. Results Evaluating the results of studies indicated inappropriate knowledge, attitude, and practice regarding infection control among Iranian dentists and dental students. Using personal protection devices and observing measures required for infection control were not in accordance with global standards. Conclusion The knowledge, attitudes, and practice of infection control in Iranian dental settings were found to be inadequate. Therefore, dentists should be educated more on the subject and special programs should be in place to monitor the dental settings for observing infection control standards. PMID:23875081

The Effectiveness of the Barton’s Intervention Program on Reading Comprehension and Reading Attitude of Students with Dyslexia

PubMed Central

Mihandoost, Zeinab; Elias, Habibah

2011-01-01

Objective: The current research tested the differences in reading attitude and reading comprehension in the dyslexic students between the control group and the experimental group following the Barton intervention program. Methods: Dyslexia screening instrument and reading text were employed in order to identify dyslexic students. The population of the study included 138 dyslexic students studying in schools in Ilam, Iran. From this population, 64 students were randomly selected and assigned to an experimental group as well as a control group. The experimental group was taught for 36 sessions, using the Barton’s method at two levels, and ten lessons were provided to improve the reading skill. The reading comprehension and reading attitude instruments were employed for the measurement of the attitude and comprehension before and after the intervention program. Results: The analysis of covariance showed a significant difference between the control group and the experimental group following the Barton intervention program. Conclusion: This study showed that dyslexic students learned to read, and a more direct instruction related to decoding could influence their progress more than the general exposure to education. PMID:24644446

Attitude control study for a large flexible spacecraft using a Solar Electric Propulsion System (SEPS)

NASA Technical Reports Server (NTRS)

Tolivar, A. F.; Key, R. W.

1980-01-01

The attitude control performance of the solar electric propulsion system (SEPS) was evaluated. A thrust vector control system for powered flight control was examined along with a gas jet reaction control system, and a reaction wheel system, both of which have been proposed for nonpowered flight control. Comprehensive computer simulations of each control system were made and evaluated using a 30 mode spacecraft model. Results obtained indicate that thrust vector control and reaction wheel systems offer acceptable smooth proportional control. The gas jet control system is shown to be risky for a flexible structure such as SEPS, and is therefore, not recommended as a primary control method.

Automating the Transition Between Sensorless Motor Control Methods for the NASA Glenn Research Center Flywheel Energy Storage System

NASA Technical Reports Server (NTRS)

Fehrmann, Elizabeth A.; Kenny, Barbara H.

2004-01-01

The NASA Glenn Research Center (GRC) has been working to advance the technology necessary for a flywheel energy storage system for the past several years. Flywheels offer high efficiency, durability, and near-complete discharge capabilities not produced by typical chemical batteries. These characteristics show flywheels to be an attractive alternative to the more typical energy storage solutions. Flywheels also offer the possibility of combining what are now two separate systems in space applications into one: energy storage, which is currently provided by batteries, and attitude control, which is currently provided by control moment gyroscopes (CMGs) or reaction wheels. To date, NASA Glenn research effort has produced the control algorithms necessary to demonstrate flywheel operation up to a rated speed of 60,000 RPM and the combined operation of two flywheel machines to simultaneously provide energy storage and single axis attitude control. Two position-sensorless algorithms are used to control the motor/generator, one for low (0 to 1200 RPM) speeds and one for high speeds. The algorithm allows the transition from the low speed method to the high speed method, but the transition from the high to low speed method was not originally included. This leads to a limitation in the existing motor/generator control code that does not allow the flywheels to be commanded to zero speed (and back in the negative speed direction) after the initial startup. In a multi-flywheel system providing both energy storage and attitude control to a spacecraft, speed reversal may be necessary.

Satellite attitude prediction by multiple time scales method

NASA Technical Reports Server (NTRS)

Tao, Y. C.; Ramnath, R.

1975-01-01

An investigation is made of the problem of predicting the attitude of satellites under the influence of external disturbing torques. The attitude dynamics are first expressed in a perturbation formulation which is then solved by the multiple scales approach. The independent variable, time, is extended into new scales, fast, slow, etc., and the integration is carried out separately in the new variables. The theory is applied to two different satellite configurations, rigid body and dual spin, each of which may have an asymmetric mass distribution. The disturbing torques considered are gravity gradient and geomagnetic. Finally, as multiple time scales approach separates slow and fast behaviors of satellite attitude motion, this property is used for the design of an attitude control device. A nutation damping control loop, using the geomagnetic torque for an earth pointing dual spin satellite, is designed in terms of the slow equation.

Male Parenting Attitudes and Batterer Intervention: Assessing Child Maltreatment Risk

ERIC Educational Resources Information Center

Burnette, Catherine E.; Ferreira, Regardt J.; Buttell, Fred

2017-01-01

Objective: The purpose of the study was to investigate the relationship between parenting attitudes and intimate partner violence (IPV) perpetration and identify factors associated with program completion for a 26-week batterer intervention program (BIP). Method: The study employed a nonequivalent, control-group design (comparing program…

Determining Students' Attitude towards Physics through Problem-Solving Strategy

ERIC Educational Resources Information Center

Erdemir, Naki

2009-01-01

In this study, the effects of teacher-directed and self-directed problem-solving strategies on students' attitudes toward physics were explored. Problem-solving strategies were used with the experimental group, while the control group was instructed using traditional teaching methods. The study was conducted with 270 students at various high…

Modifying Attitudes of Arab School Teachers toward Stuttering

ERIC Educational Resources Information Center

Abdalla, Fauzia; St. Louis, Kenneth O.

2014-01-01

Purpose: The authors of this quasi-experimental design study explored the effect of an educational documentary video that presented factual and emotional aspects of stuttering on changing attitudes toward stuttering of preservice trainees and in-service public school teachers in Kuwait. Method: Participants were 99 preservice trainees (48 control,…

Attitudes to Gun Control in an American Twin Sample: Sex Differences in the Causes of Variation.

PubMed

Eaves, Lindon J; Silberg, Judy L

2017-10-01

The genetic and social causes of individual differences in attitudes to gun control are estimated in a sample of senior male and female twin pairs in the United States. Genetic and environmental parameters were estimated by weighted least squares applied to polychoric correlations for monozygotic (MZ) and dizygotic (DZ) twins of both sexes. The analysis suggests twin similarity for attitudes to gun control in men is entirely genetic while that in women is purely social. Although the volunteer sample is small, the analysis illustrates how the well-tested concepts and methods of genetic epidemiology may be a fertile resource for deepening our scientific understanding of biological and social pathways that affect individual risk to gun violence.

Use of a knowledge-attitude-behaviour education programme for Chinese adults undergoing maintenance haemodialysis: Randomized controlled trial

PubMed Central

Liu, Li; Wang, Jing; An, Li-Wei; Jiao, Jian-Mei

2016-01-01

Objective To investigate the effects of a knowledge-attitude-behaviour health education model on acquisition of disease-related knowledge and self-management behaviour by patients undergoing maintenance haemodialysis. Methods Patients recently prescribed MHD were randomly assigned to a control group or an intervention group. Control group patients were treated with usual care and general education models. A specialist knowledge-attitude-behaviour health education model was applied to patients in the intervention group. Results Eighty-six patients were included (n = 43 per group). Before intervention, there were no significant between-group differences in disease knowledge and self-management behaviour. After 6 months’ intervention, a significant between-group difference in acquisition of disease knowledge was observed. Self-management behaviour scores (control of body mass, reasonable diet, correct drug intake, physical activity, correct fistula care, disease condition monitoring, psychological and social behaviours) for the intervention group were also higher than those for the control group. Conclusion These preliminary findings suggest that the knowledge-attitude-behaviour model appears to be a valuable tool for the health education of MHD patients. PMID:26951842

Experimental evaluation of HJB optimal controllers for the attitude dynamics of a multirotor aerial vehicle.

PubMed

Prado, Igor Afonso Acampora; Pereira, Mateus de Freitas Virgílio; de Castro, Davi Ferreira; Dos Santos, Davi Antônio; Balthazar, Jose Manoel

2018-06-01

The present paper is concerned with the design and experimental evaluation of optimal control laws for the nonlinear attitude dynamics of a multirotor aerial vehicle. Three design methods based on Hamilton-Jacobi-Bellman equation are taken into account. The first one is a linear control with guarantee of stability for nonlinear systems. The second and third are a nonlinear suboptimal control techniques. These techniques are based on an optimal control design approach that takes into account the nonlinearities present in the vehicle dynamics. The stability Proof of the closed-loop system is presented. The performance of the control system designed is evaluated via simulations and also via an experimental scheme using the Quanser 3-DOF Hover. The experiments show the effectiveness of the linear control method over the nonlinear strategy. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Adaptive fuzzy logic controller with direct action type structures for InnoSAT attitude control system

NASA Astrophysics Data System (ADS)

Bakri, F. A.; Mashor, M. Y.; Sharun, S. M.; Bibi Sarpinah, S. N.; Abu Bakar, Z.

2016-10-01

This study proposes an adaptive fuzzy controller for attitude control system (ACS) of Innovative Satellite (InnoSAT) based on direct action type structure. In order to study new methods used in satellite attitude control, this paper presents three structures of controllers: Fuzzy PI, Fuzzy PD and conventional Fuzzy PID. The objective of this work is to compare the time response and tracking performance among the three different structures of controllers. The parameters of controller were tuned on-line by adjustment mechanism, which was an approach similar to a PID error that could minimize errors between actual and model reference output. This paper also presents a Model References Adaptive Control (MRAC) as a control scheme to control time varying systems where the performance specifications were given in terms of the reference model. All the controllers were tested using InnoSAT system under some operating conditions such as disturbance, varying gain, measurement noise and time delay. In conclusion, among all considered DA-type structures, AFPID controller was observed as the best structure since it outperformed other controllers in most conditions.

Self-tuning control of attitude and momentum management for the Space Station

NASA Technical Reports Server (NTRS)

Shieh, L. S.; Sunkel, J. W.; Yuan, Z. Z.; Zhao, X. M.

1992-01-01

This paper presents a hybrid state-space self-tuning design methodology using dual-rate sampling for suboptimal digital adaptive control of attitude and momentum management for the Space Station. This new hybrid adaptive control scheme combines an on-line recursive estimation algorithm for indirectly identifying the parameters of a continuous-time system from the available fast-rate sampled data of the inputs and states and a controller synthesis algorithm for indirectly finding the slow-rate suboptimal digital controller from the designed optimal analog controller. The proposed method enables the development of digitally implementable control algorithms for the robust control of Space Station Freedom with unknown environmental disturbances and slowly time-varying dynamics.

A linear quadratic tracker for Control Moment Gyro based attitude control of the Space Station

NASA Technical Reports Server (NTRS)

Kaidy, J. T.

1986-01-01

The paper discusses a design for an attitude control system for the Space Station which produces fast response, with minimal overshoot and cross-coupling with the use of Control Moment Gyros (CMG). The rigid body equations of motion are linearized and discretized and a Linear Quadratic Regulator (LQR) design and analysis study is performed. The resulting design is then modified such that integral and differential terms are added to the state equations to enhance response characteristics. Methods for reduction of computation time through channelization are discussed as well as the reduction of initial torque requirements.

Inertia Estimation of Spacecraft Based on Modified Law of Conservation of Angular Momentum

NASA Astrophysics Data System (ADS)

Kim, Dong Hoon; Choi, Dae-Gyun; Oh, Hwa-Suk

2010-12-01

In general, the information of inertia properties is required to control a spacecraft. The inertia properties are changed by some activities such as consumption of propellant, deployment of solar panel, sloshing, etc. Extensive estimation methods have been investigated to obtain the precise inertia properties. The gyro-based attitude data including noise and bias needs to be compensated for improvement of attitude control accuracy. A modified estimation method based on the law of conservation of angular momentum is suggested to avoid inconvenience like filtering process for noiseeffect compensation. The conventional method is modified and beforehand estimated moment of inertia is applied to improve estimation efficiency of product of inertia. The performance of the suggested method has been verified for the case of STSAT-3, Korea Science Technology Satellite.

Attitudes on the Population Crisis at a Small Liberal-Arts College

ERIC Educational Resources Information Center

Jenkins, John B.; Mitchell, Robert C.

1973-01-01

A survey of attitudes of college students indicated they desired few children, were more receptive to sterilization, and had a general ignorance about methods of birth control and possible side effects of sterilization. These results are in contradiction with another, similar study. Replication of the study is suggested. (PS)

Effects of the Integrated Online Advance Organizer Teaching Materials on Students' Science Achievement and Attitude

ERIC Educational Resources Information Center

Korur, Fikret; Toker, Sacip; Eryilmaz, Ali

2016-01-01

This two-group quasi-experimental study investigated the effects of the Online Advance Organizer Concept Teaching Material (ONACOM) integrated with inquiry teaching and expository teaching methods. Grade 7 students' posttest performances on the light unit achievement and light unit attitude tests controlled for gender, previous semester science…

Influence of the Officer Retention Resource Website on Attitudes and Retention Intentions

DTIC Science & Technology

2010-09-01

Method Design A pretest - posttest control group design was used to assess the impact of the website on officers’ perceptions, attitudes, and retention...covariance (ANCOVA) approach to analyze the data from a pretest - posttest control group design because it generally offers more power than other designs ...between the pretest and posttest is large (r > .70), the gain score approach will have more power than an ANCOVA. Although about one-third of the

Adaptive super twisting vibration control of a flexible spacecraft with state rate estimation

NASA Astrophysics Data System (ADS)

Malekzadeh, Maryam; Karimpour, Hossein

2018-05-01

The robust attitude and vibration control of a flexible spacecraft trying to perform accurate maneuvers in spite of various sources of uncertainty is addressed here. Difficulties for achieving precise and stable pointing arise from noisy onboard sensors, parameters indeterminacy, outer disturbances as well as un-modeled or hidden dynamics interactions. Based on high-order sliding-mode methods, the non-minimum phase nature of the problem is dealt with through output redefinition. An adaptive super-twisting algorithm (ASTA) is incorporated with its observer counterpart on the system under consideration to get reliable attitude and vibration control in the presence of sensor noise and momentum coupling. The closed-loop efficiency is verified through simulations under various indeterminate situations and got compared to other methods.

Instructional multimedia: An investigation of student and instructor attitudes and student study behavior

PubMed Central

2011-01-01

Background Educators in allied health and medical education programs utilize instructional multimedia to facilitate psychomotor skill acquisition in students. This study examines the effects of instructional multimedia on student and instructor attitudes and student study behavior. Methods Subjects consisted of 45 student physical therapists from two universities. Two skill sets were taught during the course of the study. Skill set one consisted of knee examination techniques and skill set two consisted of ankle/foot examination techniques. For each skill set, subjects were randomly assigned to either a control group or an experimental group. The control group was taught with live demonstration of the examination skills, while the experimental group was taught using multimedia. A cross-over design was utilized so that subjects in the control group for skill set one served as the experimental group for skill set two, and vice versa. During the last week of the study, students and instructors completed written questionnaires to assess attitude toward teaching methods, and students answered questions regarding study behavior. Results There were no differences between the two instructional groups in attitudes, but students in the experimental group for skill set two reported greater study time alone compared to other groups. Conclusions Multimedia provides an efficient method to teach psychomotor skills to students entering the health professions. Both students and instructors identified advantages and disadvantages for both instructional techniques. Reponses relative to instructional multimedia emphasized efficiency, processing level, autonomy, and detail of instruction compared to live presentation. Students and instructors identified conflicting views of instructional detail and control of the content. PMID:21693058

Smoking Behaviors and Attitudes During Adolescence Prospectively Predict Support for Tobacco Control Policies in Adulthood

PubMed Central

Chassin, Laurie; Presson, Clark C.

2012-01-01

Introduction: Several cross-sectional studies have examined factors associated with support for tobacco control policies. The current study utilized a longitudinal design to test smoking status and attitude toward smoking measured in adolescence as prospective predictors of support for tobacco control policies measured in adulthood. Methods: Participants (N = 4,834) were from a longitudinal study of a Midwestern community-based sample. Hierarchical multiple regression analyses tested adolescent smoking status and attitude toward smoking as prospective predictors (after controlling for sociodemographic factors, adult smoking status, and adult attitude toward smoking) of support for regulation of smoking in public places, discussion of the dangers of smoking in public schools, prohibiting smoking in bars, eliminating smoking on television and in movies, prohibiting smoking in restaurants, and increasing taxes on cigarettes. Results: Participants who smoked during adolescence demonstrated more support for discussion of the dangers of smoking in public schools and less support for increasing taxes on cigarettes but only among those who smoked as adults. Those with more positive attitudes toward smoking during adolescence demonstrated less support as adults for prohibiting smoking in bars and eliminating smoking on television and in movies. Moreover, a significant interaction indicated that those with more positive attitudes toward smoking as adolescents demonstrated less support as adults for prohibiting smoking in restaurants, but only if they became parents as adults. Conclusions: This study’s findings suggest that interventions designed to deter adolescent smoking may have future benefits in increasing support for tobacco control policies. PMID:22193576

Evaluation of Eating Attitude in Patients with Migraine

PubMed Central

DEMİRCİ, Kadir; DEMİRCİ, Seden; AKPINAR, Abdullah; DEMİRDAŞ, Arif; ATAY, İnci Meltem

2015-01-01

Introduction This study aimed to investigate the eating attitudes in patients with migraine. Methods Fifty-nine patients (mean age: 32.54±8.47 years) diagnosed with migraine according to the International Classification of Headache Disorder, 2004, and 47 age-, gender- and education-matched healthy controls (mean age: 31.85±7.14 years) were enrolled for this study. Sociodemographic data were recorded, and the body mass index was calculated as kilograms per meter squared. Data regarding the duration of illness and attack, frequency of migraine attacks, and the presence of aura were recorded. Migraine severity was assessed by Migraine Disability Assessment Score (MIDAS). Eating Attitudes Test (EAT), Beck Depression Inventory (BDI), and Beck Anxiety Inventory were applied to all participants. Results The patients with migraine had significantly higher EAT scores, levels of anxiety, and depression than controls (p<.01). Furthermore, 11.9% of patients with migraine had an EAT score of 30 or higher, which is suggestive of a disordered eating attitude, whereas this rate was 2.1% in healthy controls (p<.05). The scores of EAT and BDI had positive correlation with the scores of MIDAS in patients with migraine (r=.298, p<.05; r=.332, p=.01, respectively). Conclusion In our study, disordered eating attitudes and the levels of anxiety and depression were high in patients with migraine than controls. Our study is important to demonstrate the connection between migraine and disordered eating attitudes. PMID:28360741

Effect of levels of inquiry model of science teaching on scientific literacy domain attitudes

NASA Astrophysics Data System (ADS)

Achmad, Maulana; Suhandi, Andi

2017-05-01

The aim of this research was to obtain an overview of the increase scientific literacy attitudes domain in high school students as the effects of the Levels of Inquiry (LOI) model of science teaching. This research using a quasi-experimental methods and randomizedpretest-posttest control group design. The subject of this research was students of grade X in a senior high school in Purwakarta and it consists of two classes who were divided into experimental class (30 students) and control class (30 students). While experimental class was taught LOIand control class was taught Interactive Lecture Demonstration (ILD). Data were collected using an attitude scale scientific literacy test which is based on the Likert scale. Data were analyzed using normality test, homogeneity test, and t-test to the value of N-gain attitude of scientific literacy scale test. The result of percentage average N-gain experimental class and control are 49 and 31 that classified into medium improvement category. Based on the results of hypothesis testing on the N-gain value obtained by the Sig.(One-tailed) 0.000 < 0.050, it means that H1 was accepted. The results showed that scientific literacy domain attitude of students who got learning by LOI is higher than students who got learning by ILD. It can be concluded that the effect of LOI is better to improve scientific literacy domain attitudes significantly.

Psychiatric Nurses' Attitudes Towards Violent Behaviour: A Brazilian Study.

PubMed

Dias, Maraína Gomes Pires Fernandes; de Vargas, Divane

2018-02-13

This study examines nurses' attitudes towards violent behaviour and the management of aggressiveness. A convenience sample of 185 nurses working in psychiatric urgent care and emergency services in Brazil responded to the MAVAS-BR. The results show that nurses' attitudes are more reflective of the external and situational models of violent behaviour and the use of control methods to manage aggressiveness. The mapping of this phenomenon using the same tools in a different context from those traditionally studied while observing similar results suggests a pattern of attitudes towards violent behaviour and the management of aggressiveness among nurses around the world.

A novel single thruster control strategy for spacecraft attitude stabilization

NASA Astrophysics Data System (ADS)

Godard; Kumar, Krishna Dev; Zou, An-Min

2013-05-01

Feasibility of achieving three axis attitude stabilization using a single thruster is explored in this paper. Torques are generated using a thruster orientation mechanism with which the thrust vector can be tilted on a two axis gimbal. A robust nonlinear control scheme is developed based on the nonlinear kinematic and dynamic equations of motion of a rigid body spacecraft in the presence of gravity gradient torque and external disturbances. The spacecraft, controlled using the proposed concept, constitutes an underactuated system (a system with fewer independent control inputs than degrees of freedom) with nonlinear dynamics. Moreover, using thruster gimbal angles as control inputs make the system non-affine (control terms appear nonlinearly in the state equation). This necessitates the control algorithms to be developed based on nonlinear control theory since linear control methods are not directly applicable. The stability conditions for the spacecraft attitude motion for robustness against uncertainties and disturbances are derived to establish the regions of asymptotic 3-axis attitude stabilization. Several numerical simulations are presented to demonstrate the efficacy of the proposed controller and validate the theoretical results. The control algorithm is shown to compensate for time-varying external disturbances including solar radiation pressure, aerodynamic forces, and magnetic disturbances; and uncertainties in the spacecraft inertia parameters. The numerical results also establish the robustness of the proposed control scheme to negate disturbances caused by orbit eccentricity.

Fault tolerant attitude sensing and force feedback control for unmanned aerial vehicles

NASA Astrophysics Data System (ADS)

Jagadish, Chirag

Two aspects of an unmanned aerial vehicle are studied in this work. One is fault tolerant attitude determination and the other is to provide force feedback to the joy-stick of the UAV so as to prevent faulty inputs from the pilot. Determination of attitude plays an important role in control of aerial vehicles. One way of defining the attitude is through Euler angles. These angles can be determined based on the measurements of the projections of the gravity and earth magnetic fields on the three body axes of the vehicle. Attitude determination in unmanned aerial vehicles poses additional challenges due to limitations of space, payload, power and cost. Therefore it provides for almost no room for any bulky sensors or extra sensor hardware for backup and as such leaves no room for sensor fault issues either. In the face of these limitations, this study proposes a fault tolerant computing of Euler angles by utilizing multiple different computation methods, with each method utilizing a different subset of the available sensor measurement data. Twenty-five such methods have been presented in this document. The capability of computing the Euler angles in multiple ways provides a diversified redundancy required for fault tolerance. The proposed approach can identify certain sets of sensor failures and even separate the reference fields from the disturbances. A bank-to-turn maneuver of the NASA GTM UAV is used to demonstrate the fault tolerance provided by the proposed method as well as to demonstrate the method of determining the correct Euler angles despite interferences by inertial acceleration disturbances. Attitude computation is essential for stability. But as of today most UAVs are commanded remotely by human pilots. While basic stability control is entrusted to machine or the on-board automatic controller, overall guidance is usually with humans. It is therefore the pilot who sets the command/references through a joy-stick. While this is a good compromise between complete automation and complete human control, it still poses some unique challenges. Pilots of manned aircraft are present inside the cockpit of the aircraft they fly and thus have a better feel of the flying environment and also the limitations of the flight. The same might not be true for UAV pilots stationed on the ground. A major handicap is that visual feedback is the only one available for the UAV pilot. An additional parameter like force feedback on the remote control joy-stick can help the UAV pilot to physically feel the limitation of the safe flight envelope. This can make the flying itself easier and safer. A method proposed here is to design a joy-stick assembly with an additional actuator. This actuator is controlled so as to generate a force feedback on the joy-stick. The control developed for this system is such that the actuator allows free movement for the pilot as long as the UAV is within the safe flight envelope. On the other hand, if it is outside this safe range, the actuator opposes the pilot's applied torque and prevents him/her from giving erroneous commands to the UAV.

Spacecraft Attitude Tracking and Maneuver Using Combined Magnetic Actuators

NASA Technical Reports Server (NTRS)

Zhou, Zhiqiang

2012-01-01

A paper describes attitude-control algorithms using the combination of magnetic actuators with reaction wheel assemblies (RWAs) or other types of actuators such as thrusters. The combination of magnetic actuators with one or two RWAs aligned with different body axis expands the two-dimensional control torque to three-dimensional. The algorithms can guarantee the spacecraft attitude and rates to track the commanded attitude precisely. A design example is presented for nadir-pointing, pitch, and yaw maneuvers. The results show that precise attitude tracking can be reached and the attitude- control accuracy is comparable with RWA-based attitude control. When there are only one or two workable RWAs due to RWA failures, the attitude-control system can switch to the control algorithms for the combined magnetic actuators with the RWAs without going to the safe mode, and the control accuracy can be maintained. The attitude-control algorithms of the combined actuators are derived, which can guarantee the spacecraft attitude and rates to track the commanded values precisely. Results show that precise attitude tracking can be reached, and the attitude-control accuracy is comparable with 3-axis wheel control.

In-orbit performance of the ITOS improved attitude control system with Hall generator brushless motor and earth-splitting technique

NASA Technical Reports Server (NTRS)

Peacock, W. M.

1973-01-01

The National Aeronautics and Space Administration (NASA), launched ITOS-D with an improved attitude control system. A Hall generator brushless dc torque motor replaced the brush dc torque motor on Tiros-M and ITOS-A. Two CO2 attitude horizon sensors and one mirror replaced the four wideband horizon sensors and two mirrors on ITOS-1 and NOAA-1. Redundant pitch-control electronic boxes containing additional electronic circuitry for earth-splitting and brushless motor electronics were used. A method of generating a spacecraft earth-facing side reference for comparison to the time occurrence of the earth-splitting pulse was used to automatically correct pitch-attitude error. A single rotating flywheel, supported by a single bearing, provided gyroscopic stability and the required momentum interchange to keep one side of the satellite facing the earth. Magnetic torquing against the earth's magnetic field eliminated the requirement for expendable propellants which would limit satellite life in orbit.

A study of attitude control concepts for precision-pointing non-rigid spacecraft

NASA Technical Reports Server (NTRS)

Likins, P. W.

1975-01-01

Attitude control concepts for use onboard structurally nonrigid spacecraft that must be pointed with great precision are examined. The task of determining the eigenproperties of a system of linear time-invariant equations (in terms of hybrid coordinates) representing the attitude motion of a flexible spacecraft is discussed. Literal characteristics are developed for the associated eigenvalues and eigenvectors of the system. A method is presented for determining the poles and zeros of the transfer function describing the attitude dynamics of a flexible spacecraft characterized by hybrid coordinate equations. Alterations are made to linear regulator and observer theory to accommodate modeling errors. The results show that a model error vector, which evolves from an error system, can be added to a reduced system model, estimated by an observer, and used by the control law to render the system less sensitive to uncertain magnitudes and phase relations of truncated modes and external disturbance effects. A hybrid coordinate formulation using the provided assumed mode shapes, rather than incorporating the usual finite element approach is provided.

Parental overprotection engenders dysfunctional attitudes about achievement and dependency in a gender-specific manner

PubMed Central

2013-01-01

Background It has been suggested that dysfunctional attitudes, cognitive vulnerability to depression, have developmental origins. The present study examined the effects of parental rearing on dysfunctional attitudes in three areas of life with special attention to gender specificity. Methods The subjects were 665 Japanese healthy volunteers. Dysfunctional attitudes were assessed by the 24-item Dysfunctional Attitude Scale, which has the Achievement, Dependency and Self-control subscales. Perceived parental rearing was assessed by the Parental Bonding Instrument, which has the Care and Protection subscales. Results Higher scores of the Achievement (β = 0.293, p < 0.01) and Dependency (β = 0.224, p < 0.05) subscales were correlated with higher scores of the Protection subscale in the combination of mother and daughter, but not in other combinations of parents and recipients. Scores of the Self-control subscale were not correlated with paternal or maternal rearing scores. Conclusions The present study suggests that parental overprotection engenders dysfunctional attitudes about achievement and dependency in a gender-specific manner. PMID:24365104

In flight estimations of Cassini spacecraft inertia tensor and thruster magnitude

NASA Technical Reports Server (NTRS)

Feldman, Antonette; Lee, Allan Y.

2006-01-01

This paper describes two methods used by the Cassini Attitude Control team to determine these key parameters and how flight telemetry was used to estimate them. The method for estimating the spacecraft inertia tensor exploits the conservation of angular momentum during spacecraft slews under reaction wheel control.

Influence of Joyful Learning on Elementary School Students’ Attitudes Toward Science

NASA Astrophysics Data System (ADS)

Anggoro, S.; Sopandi, W.; Sholehuddin, M.

2017-02-01

This study investigated the effects of joyful learning approach on elementary school students’ attitudes toward science. The method used is quasy experiment with the participants were divided into two groups. Thirty three of 4th grade students volunteered as an experimental group, and the other forty two act as a control group. The data was collected by questionnaire that are given before and after the lesson, observation sheet, and interview. The effect of joyful learning on students’ attitude was obtained by determining the n-gain and independent t-test. Observation and interview results were used to triangulate and support the quantitative findings. The data showed that the gain scores of the experimental group students’ attitudes toward science were significantly higher than the gain scores of control group. In addition, the experimental group made significantly greater progress in their cognitive, affective and conative experiences. Interviews and observations indicated that their attitude toward science changed over the intervention. This indicated that joyful learning approach can enhance the elementary school students’ attitudes toward science. According to these findings, it can be concluded that joyful learning approach can be used as an alternative approach to improve student’s attitude toward science.

Noise screen for attitude control system

NASA Technical Reports Server (NTRS)

Rodden, John J. (Inventor); Stevens, Homer D. (Inventor); Hong, David P. (Inventor); Hirschberg, Philip C. (Inventor)

2002-01-01

An attitude control system comprising a controller and a noise screen device coupled to the controller. The controller is adapted to control an attitude of a vehicle carrying an actuator system that is adapted to pulse in metered bursts in order to generate a control torque to control the attitude of the vehicle in response to a control pulse. The noise screen device is adapted to generate a noise screen signal in response to the control pulse that is generated when an input attitude error signal exceeds a predetermined deadband attitude level. The noise screen signal comprises a decaying offset signal that when combined with the attitude error input signal results in a net attitude error input signal away from the predetermined deadband level to reduce further control pulse generation.

Methods of fertility control in cats: Owner, breeder and veterinarian behavior and attitudes.

PubMed

Murray, Jane K; Mosteller, Jill R; Loberg, Jenny M; Andersson, Maria; Benka, Valerie A W

2015-09-01

Fertility control is important for population management of owned and unowned cats, provides health benefits at the individual level and can reduce unwanted sexually dimorphic behaviors such as roaming, aggression, spraying and calling. This article reviews the available evidence regarding European and American veterinarian, owner and pedigree cat breeder attitudes toward both surgical sterilization and non-surgical fertility control. It additionally presents new data on veterinarians' and pedigree cat breeders' use of, and attitudes toward, alternative modalities of fertility control. Within the United States and Europe, the proportion of cats reported to be sterilized varies widely. Published estimates range from 27-93% for owned cats and 2-5% for cats trapped as part of a trap-neuter-return (TNR) program. In some regions and populations of cats, non-surgical fertility control is also used. Social context, cultural norms, individual preferences, economic considerations, legislation and professional organizations may all influence fertility control decisions for cats. Particularly in Europe, a limited number of non-surgical temporary contraceptives are available for cats; these include products with regulatory approval for cats as well as some used 'off label'. Non-surgical methods remove the risk of complications related to surgery and offer potential to treat more animals in less time and at lower cost; they may also appeal to pedigree cat breeders seeking temporary contraception. However, concerns over efficacy, delivery methods, target species safety, duration and side effects exist with current non-surgical options. Research is under way to develop new methods to control fertility in cats without surgery. US and European veterinarians place high value on three perceived benefits of surgical sterilization: permanence, behavioral benefits and health benefits. Non-surgical options will likely need to share these benefits to be widely accepted by the veterinary community. © The Author(s) 2015.

Planar rigid-flexible coupling spacecraft modeling and control considering solar array deployment and joint clearance

NASA Astrophysics Data System (ADS)

Li, Yuanyuan; Wang, Zilu; Wang, Cong; Huang, Wenhu

2018-01-01

Based on Nodal Coordinate Formulation (NCF) and Absolute Nodal Coordinate Formulation (ANCF), this paper establishes rigid-flexible coupling dynamic model of the spacecraft with large deployable solar arrays and multiple clearance joints to analyze and control the satellite attitude under deployment disturbance. Considering torque spring, close cable loop (CCL) configuration and latch mechanisms, a typical spacecraft composed of a rigid main-body described by NCF and two flexible panels described by ANCF is used as a demonstration case. Nonlinear contact force model and modified Coulomb friction model are selected to establish normal contact force and tangential friction model, respectively. Generalized elastic force are derived and all generalized forces are defined in the NCF-ANCF frame. The Newmark-β method is used to solve system equations of motion. The availability and superiority of the proposed model is verified through comparing with numerical co-simulations of Patran and ADAMS software. The numerical results reveal the effects of panel flexibility, joint clearance and their coupling on satellite attitude. The effects of clearance number, clearance size and clearance stiffness on satellite attitude are investigated. Furthermore, a proportional-differential (PD) attitude controller of spacecraft is designed to discuss the effect of attitude control on the dynamic responses of the whole system.

The Effect of Portfolio Assessments on Metacognitive Skills and on Attitudes toward a Course

ERIC Educational Resources Information Center

Gencel, Ilke Evin

2017-01-01

The aim of this study is to determine through teacher candidates' thoughts the effects of a portfolio assessment implementation on their metacognitive skills and attitudes towards a course on measurement and evaluation. Exploratory sequential mixed-methods design is employed within the study. The pretest/posttest control group design was used in…

The Effect of Using Metacognitive Strategies for Solving Geometry Problems on Students' Achievement and Attitude

ERIC Educational Resources Information Center

Mandaci Sahin, Seher; Kendir, Fatma

2013-01-01

The purpose of this study is to identify the effect of using metacognitive strategies for problem solving in "geometry" on fifth grade students' achievement, metacognitive skills and attitude. Experimental method was used with a pretest/posttest control group design. Firstly, both groups were subject to a pretest that was comprised of…

Male Batterer Parenting Attitudes: Investigating Differences between African American and Caucasian Men

ERIC Educational Resources Information Center

Ferreira, Regardt J.; Lauve-Moon, Katie; Cannon, Clare

2017-01-01

Objective: The purpose of the study was to investigate the differences between intimate partner violence (IPV) and parenting attitudes by race by comparing demographic, parenting, and IPV indicators for African American and White men. Method: The study employed a nonequivalent, control group design in a secondary analysis of 111 men. Results:…

"Earth, Sun and Moon": Computer Assisted Instruction in Secondary School Science--Achievement and Attitudes

ERIC Educational Resources Information Center

Ercan, Orhan; Bilen, Kadir; Ural, Evrim

2016-01-01

This study investigated the impact of a web-based teaching method on students' academic achievement and attitudes in the elementary education fifth grade Science and Technology unit, "System of Earth, Sun and Moon". The study was a quasi-experimental study with experimental and control groups comprising 54 fifth grade students attending…

Torque equilibrium attitudes for the Space Station

NASA Technical Reports Server (NTRS)

Thompson, Roger C.

1993-01-01

All spacecraft orbiting in a low earth orbit (LEO) experience external torques due to environmental effects. Examples of these torques include those induced by aerodynamic, gravity-gradient, and solar forces. It is the gravity-gradient and aerodynamic torques that produce the greatest disturbances to the attitude of a spacecraft in LEO, and large asymmetric spacecraft, such as the space station, are affected to a greater degree because the magnitude of the torques will, in general, be larger in proportion to the moments of inertia. If left unchecked, these torques would cause the attitude of the space station to oscillate in a complex manner and the resulting motion would destroy the micro-gravity environment as well as prohibit the orbiter from docking. The application of control torques will maintain the proper attitude, but the controllers have limited momentum capacity. When any controller reaches its limit, propellant must then be used while the device is reset to a zero or negatively-biased momentum state. Consequently, the rate at which momentum is accumulated is a significant factor in the amount of propellant used and the frequency of resupply necessary to operate the station. A torque profile in which the area curve for a positive torque is not equal to the area under the curve for a negative torque is 'biased,' and the consequent momentum build-up about that axis is defined as secular momentum because it continues to grow with time. Conversely, when the areas are equal, the momentum is cyclic and bounded. A Torque Equilibrium Attitude (TEA) is thus defined as an attitude at which the external torques 'balance' each other as much as possible, and which will result in lower momentum growth in the controllers. Ideally, the positive and negative external moments experienced by a spacecraft at the TEA would exactly cancel each other out and small cyclic control torques would be required only for precise attitude control. Over time, the only momentum build-up in the controllers would be due to electro-mechanical losses within the device. However, the atmospheric torques are proportional to the density of the atmosphere and the density varies with the orbital position, time of day, time of year, and the solar cycle. In addition, there are unmodeled disturbances and uncertainties in the mass and inertias. Therefore, there is no constant attitude that will completely balance the environmental torques and the dynamic TEA cannot be solved in closed form. The objective of this research was to determine a method to calculate a dynamic TEA such that the rate of momentum build-up in the controllers would be minimized and to implement this method in the MATRIX(x) simulation software by Integrated Systems, Inc.

Venusian atmospheric and Magellan properties from attitude control data. M.S. Thesis

NASA Technical Reports Server (NTRS)

Croom, Christopher A.; Tolson, Robert H.

1994-01-01

Results are presented of the study of the Venusian atmosphere, Magellan aerodynamic moment coefficients, moments of inertia, and solar moment coefficients. This investigation is based upon the use of attitude control data in the form of reaction wheel speeds from the Magellan spacecraft. As the spacecraft enters the upper atmosphere of Venus, measurable torques are experienced due to aerodynamic effects. Solar and gravity gradient effects also cause additional torques throughout the orbit. In order to maintain an inertially fixed attitude, the control system counteracts these torques by changing the angular rates of three reaction wheels. Model reaction wheel speeds are compared to observed Magellan reaction wheel speeds through a differential correction procedure. This method determines aerodynamic, atmospheric, solar pressure, and mass moment of inertia parameters. Atmospheric measurements include both base densities and scale heights. Atmospheric base density results confirm natural variability as measured by the standard orbital decay method. Potential inconsistencies in free molecular aerodynamic moment coefficients are identified. Moments of inertia are determined with a precision better than 1 percent of the largest principal moment of inertia.

USE OF THE SDO POINTING CONTROLLERS FOR INSTRUMENT CALIBRATION MANEUVERS

NASA Technical Reports Server (NTRS)

Vess, Melissa F.; Starin, Scott R.; Morgenstern, Wendy M.

2005-01-01

During the science phase of the Solar Dynamics Observatory mission, the three science instruments require periodic instrument calibration maneuvers with a frequency of up to once per month. The command sequences for these maneuvers vary in length from a handful of steps to over 200 steps, and individual steps vary in size from 5 arcsec per step to 22.5 degrees per step. Early in the calibration maneuver development, it was determined that the original attitude sensor complement could not meet the knowledge requirements for the instrument calibration maneuvers in the event of a sensor failure. Because the mission must be single fault tolerant, an attitude determination trade study was undertaken to determine the impact of adding an additional attitude sensor versus developing alternative, potentially complex, methods of performing the maneuvers in the event of a sensor failure. To limit the impact to the science data capture budget, these instrument calibration maneuvers must be performed as quickly as possible while maintaining the tight pointing and knowledge required to obtain valid data during the calibration. To this end, the decision was made to adapt a linear pointing controller by adjusting gains and adding an attitude limiter so that it would be able to slew quickly and still achieve steady pointing once on target. During the analysis of this controller, questions arose about the stability of the controller during slewing maneuvers due to the combination of the integral gain, attitude limit, and actuator saturation. Analysis was performed and a method for disabling the integral action while slewing was incorporated to ensure stability. A high fidelity simulation is used to simulate the various instrument calibration maneuvers.

Enhanced Attitude Control Experiment for SSTI Lewis Spacecraft

NASA Technical Reports Server (NTRS)

Maghami, Peoman G.

1997-01-01

The enhanced attitude control system experiment is a technology demonstration experiment on the NASA's small spacecraft technology initiative program's Lewis spacecraft to evaluate advanced attitude control strategies. The purpose of the enhanced attitude control system experiment is to evaluate the feasibility of designing and implementing robust multi-input/multi-output attitude control strategies for enhanced pointing performance of spacecraft to improve the quality of the measurements of the science instruments. Different control design strategies based on modern and robust control theories are being considered for the enhanced attitude control system experiment. This paper describes the experiment as well as the design and synthesis of a mixed H(sub 2)/H(sub infinity) controller for attitude control. The control synthesis uses a nonlinear programming technique to tune the controller parameters and impose robustness and performance constraints. Simulations are carried out to demonstrate the feasibility of the proposed attitude control design strategy. Introduction

Multivariable control of a forward swept wing aircraft. M.S. Thesis

NASA Technical Reports Server (NTRS)

Quinn, W. W.

1986-01-01

The impact of independent canard and flaperon control of the longitudinal axis of a generic forward swept wing aircraft is examined. The Linear Quadratic Gaussian (LQG)/Loop Transfer Recovery (LTR) method is used to design three compensators: two single-input-single-output (SISO) systems, one with angle of attack as output and canard as control, the other with pitch attitude as output and canard as control, and a two-input-two-output system with both canard and flaperon controlling both the pitch attitude and angle of attack. The performances of the three systems are compared showing the addition of flaperon control allows the aircraft to perform in the precision control modes with very little loss of command following accuracy.

Attitude Determination Using a MEMS-Based Flight Information Measurement Unit

PubMed Central

Ma, Der-Ming; Shiau, Jaw-Kuen; Wang, I.-Chiang; Lin, Yu-Heng

2012-01-01

Obtaining precise attitude information is essential for aircraft navigation and control. This paper presents the results of the attitude determination using an in-house designed low-cost MEMS-based flight information measurement unit. This study proposes a quaternion-based extended Kalman filter to integrate the traditional quaternion and gravitational force decomposition methods for attitude determination algorithm. The proposed extended Kalman filter utilizes the evolution of the four elements in the quaternion method for attitude determination as the dynamic model, with the four elements as the states of the filter. The attitude angles obtained from the gravity computations and from the electronic magnetic sensors are regarded as the measurement of the filter. The immeasurable gravity accelerations are deduced from the outputs of the three axes accelerometers, the relative accelerations, and the accelerations due to body rotation. The constraint of the four elements of the quaternion method is treated as a perfect measurement and is integrated into the filter computation. Approximations of the time-varying noise variances of the measured signals are discussed and presented with details through Taylor series expansions. The algorithm is intuitive, easy to implement, and reliable for long-term high dynamic maneuvers. Moreover, a set of flight test data is utilized to demonstrate the success and practicality of the proposed algorithm and the filter design. PMID:22368455

Attitude determination using a MEMS-based flight information measurement unit.

PubMed

Ma, Der-Ming; Shiau, Jaw-Kuen; Wang, I-Chiang; Lin, Yu-Heng

2012-01-01

Obtaining precise attitude information is essential for aircraft navigation and control. This paper presents the results of the attitude determination using an in-house designed low-cost MEMS-based flight information measurement unit. This study proposes a quaternion-based extended Kalman filter to integrate the traditional quaternion and gravitational force decomposition methods for attitude determination algorithm. The proposed extended Kalman filter utilizes the evolution of the four elements in the quaternion method for attitude determination as the dynamic model, with the four elements as the states of the filter. The attitude angles obtained from the gravity computations and from the electronic magnetic sensors are regarded as the measurement of the filter. The immeasurable gravity accelerations are deduced from the outputs of the three axes accelerometers, the relative accelerations, and the accelerations due to body rotation. The constraint of the four elements of the quaternion method is treated as a perfect measurement and is integrated into the filter computation. Approximations of the time-varying noise variances of the measured signals are discussed and presented with details through Taylor series expansions. The algorithm is intuitive, easy to implement, and reliable for long-term high dynamic maneuvers. Moreover, a set of flight test data is utilized to demonstrate the success and practicality of the proposed algorithm and the filter design.

Analysis of Pan-European attitudes to the eradication and control of bovine viral diarrhoea.

PubMed

Heffernan, C; Misturelli, F; Nielsen, L; Gunn, G J; Yu, J

2009-02-07

At present, national-level policies concerning the eradication and control of bovine viral diarrhoea (BVD) differ widely across Europe. Some Scandinavian countries have enacted strong regulatory frameworks to eradicate the disease, whereas other countries have few formal policies. To examine these differences, the attitudes of stakeholders and policy makers in 17 European countries were investigated. A web-based questionnaire was sent to policy makers, government and private sector veterinarians, and representatives of farmers' organisations. In total, 131 individuals responded to the questionnaire and their responses were analysed by applying a method used in sociolinguistics: frame analysis. The results showed that the different attitudes of countries that applied compulsory or voluntary frameworks were associated with different views about the attribution or blame for BVD and the roles ascribed to farmers and other stakeholders in its eradication and control.

How to reduce the latent social risk of disease: the determinants of vaccination against rabies in Taiwan.

PubMed

Ku-Yuan, Lee; Li-Chi, Lan; Jiun-Hao, Wang; Chen-Ling, Fang; Kun-Sun, Shiao

2014-06-04

To control the latent social risk of disease, the government usually spreads accurate information and attempts to improve the public's attitude toward adopting prevention. However, these methods with the Knowledge, Attitudes, and Practices (KAP) model do not always work. Therefore, we used the theory of planned behavior (TPB) to understand dog owners' behavior and distinguished the knowledge effect as objective knowledge (OK) and subjective knowledge (SK). A total of 310 dog owners completed a questionnaire based on our model. We employed structural equation modeling to verify the structural relationships and found three main results. First, our model was fit, and each path was significant. People with better attitudes, stronger subjective norms, and more perceptive behavioral control have stronger behavioral intention. Second, perceived behavioral control, not attitude, was the best predictive index in this model. Finally, on perceived behavioral control, subjective knowledge showed more influence than objective knowledge. We successfully extended TPB to explain the behavioral intention of dog owners and presented more workable recommendations. To reduce the latent social risk of disease, the government should not only address dog owners' attitudes, but also their subjective norms and perceptive behavioral control. Indeed, perceptive behavioral control and SK showed the most influence in this model. It is implied that the self-efficacy of dog owners is the most important factor in such a behavior. Therefore, the government should focus on enhancing dog owners' self-efficacy first while devoted to prevention activities.

How to Reduce the Latent Social Risk of Disease: The Determinants of Vaccination against Rabies in Taiwan

PubMed Central

Ku-Yuan, Lee; Li-Chi, Lan; Jiun-Hao, Wang; Chen-Ling, Fang; Kun-Sun, Shiao

2014-01-01

To control the latent social risk of disease, the government usually spreads accurate information and attempts to improve the public’s attitude toward adopting prevention. However, these methods with the Knowledge, Attitudes, and Practices (KAP) model do not always work. Therefore, we used the theory of planned behavior (TPB) to understand dog owners’ behavior and distinguished the knowledge effect as objective knowledge (OK) and subjective knowledge (SK). A total of 310 dog owners completed a questionnaire based on our model. We employed structural equation modeling to verify the structural relationships and found three main results. First, our model was fit, and each path was significant. People with better attitudes, stronger subjective norms, and more perceptive behavioral control have stronger behavioral intention. Second, perceived behavioral control, not attitude, was the best predictive index in this model. Finally, on perceived behavioral control, subjective knowledge showed more influence than objective knowledge. We successfully extended TPB to explain the behavioral intention of dog owners and presented more workable recommendations. To reduce the latent social risk of disease, the government should not only address dog owners’ attitudes, but also their subjective norms and perceptive behavioral control. Indeed, perceptive behavioral control and SK showed the most influence in this model. It is implied that the self-efficacy of dog owners is the most important factor in such a behavior. Therefore, the government should focus on enhancing dog owners’ self-efficacy first while devoted to prevention activities. PMID:24901413

Robust, Practical Adaptive Control for Launch Vehicles

NASA Technical Reports Server (NTRS)

Orr, Jeb. S.; VanZwieten, Tannen S.

2012-01-01

A modern mechanization of a classical adaptive control concept is presented with an application to launch vehicle attitude control systems. Due to a rigorous flight certification environment, many adaptive control concepts are infeasible when applied to high-risk aerospace systems; methods of stability analysis are either intractable for high complexity models or cannot be reconciled in light of classical requirements. Furthermore, many adaptive techniques appearing in the literature are not suitable for application to conditionally stable systems with complex flexible-body dynamics, as is often the case with launch vehicles. The present technique is a multiplicative forward loop gain adaptive law similar to that used for the NASA X-15 flight research vehicle. In digital implementation with several novel features, it is well-suited to application on aerodynamically unstable launch vehicles with thrust vector control via augmentation of the baseline attitude/attitude-rate feedback control scheme. The approach is compatible with standard design features of autopilots for launch vehicles, including phase stabilization of lateral bending and slosh via linear filters. In addition, the method of assessing flight control stability via classical gain and phase margins is not affected under reasonable assumptions. The algorithm s ability to recover from certain unstable operating regimes can in fact be understood in terms of frequency-domain criteria. Finally, simulation results are presented that confirm the ability of the algorithm to improve performance and robustness in realistic failure scenarios.

A Cross-Site Intervention in Chinese Rural Migrants Enhances HIV/AIDS Knowledge, Attitude and Behavior

PubMed Central

Li, Ning; Li, Xiaomei; Wang, Xueliang; Shao, Jin; Dou, Juanhua

2014-01-01

Background: With the influx of rural migrants into urban areas, the spread of HIV has increased significantly in Shaanxi Province (China). Migrant workers are at high risk of HIV infection due to social conditions and hardships (isolation, separation, marginalization, barriers to services, etc.). Objective: We explored the efficacy of a HIV/AIDS prevention and control program for rural migrants in Shaanxi Province, administered at both rural and urban sites. Methods: Guidance concerning HIV/AIDS prevention was given to the experimental group (266 migrants) for 1 year by the center of disease control, community health agencies and family planning department. The intervention was conducted according to the HIV/AIDS Prevention Management Manual for Rural Migrants. A control group of migrants only received general population intervention. The impact of the intervention was evaluated by administering HIV/AIDS knowledge, attitudes and sexual behavior (KAB) questionnaires after 6 and 12 months. Results: In the experimental group; 6 months of intervention achieved improvements in HIV/AIDS related knowledge. After 12 months; HIV/AIDS-related knowledge reached near maximal scores. Attitude and most behaviors scores were significantly improved. Moreover; the experimental group showed significant differences in HIV-AIDS knowledge; attitude and most behavior compared with the control group. Conclusions: The systematic long-term cross-site HIV/AIDS prevention in both rural and urban areas is a highly effective method to improve HIV/AIDS KAB among rural migrants. PMID:24762671

Neural network-based sliding mode control for atmospheric-actuated spacecraft formation using switching strategy

NASA Astrophysics Data System (ADS)

Sun, Ran; Wang, Jihe; Zhang, Dexin; Shao, Xiaowei

2018-02-01

This paper presents an adaptive neural networks-based control method for spacecraft formation with coupled translational and rotational dynamics using only aerodynamic forces. It is assumed that each spacecraft is equipped with several large flat plates. A coupled orbit-attitude dynamic model is considered based on the specific configuration of atmospheric-based actuators. For this model, a neural network-based adaptive sliding mode controller is implemented, accounting for system uncertainties and external perturbations. To avoid invalidation of the neural networks destroying stability of the system, a switching control strategy is proposed which combines an adaptive neural networks controller dominating in its active region and an adaptive sliding mode controller outside the neural active region. An optimal process is developed to determine the control commands for the plates system. The stability of the closed-loop system is proved by a Lyapunov-based method. Comparative results through numerical simulations illustrate the effectiveness of executing attitude control while maintaining the relative motion, and higher control accuracy can be achieved by using the proposed neural-based switching control scheme than using only adaptive sliding mode controller.

Can teaching research methodology influence students' attitude toward science? Cohort study and nonrandomized trial in a single medical school.

PubMed

Vujaklija, Ana; Hren, Darko; Sambunjak, Dario; Vodopivec, Ivana; Ivanis, Ana; Marusić, Ana; Marusić, Matko

2010-02-01

Medical teaching aims to develop attitudes and behaviors underlying professional competence of future physicians. We investigated whether a mandatory course on scientific methodology in the second study year could affect students' attitudes toward science in medicine. In a longitudinal study, students (n = 241) enrolling in 2001-2002 academic year at a single medical school were followed up until graduation in 2006-2007. Each year, they filled out a Likert-type questionnaire of 18 statements evaluating attitude toward science. Direct influence of the course on students' attitudes was tested in a nonrandomized controlled trial with the 2006-2007 second year student cohort. Positive students' attitudes toward science increased during study years (mean [SD] score of the maximum score of 90): from 57.6 (6.0) in the first to 69.8 (10.4) in the sixth year. There was a significant trend of increase in attitudes with the years of study (cubic trend by polynomial contrasts analysis, P = 0.011). Attendance of a course on research methodology significantly increased positive attitudes (score, 67.0 [7.0] before and 70.8 [7.5] after course, P = 0.032 vs control group), regardless of grade point average. The intervention had an effect even when the influence of the initial attitude was accounted for (F1,140 = 9.25, P = 0.003; analysis of covariance). The attitude changes after the course was greatest in students with low initial attitude scores (Spearman rinitial score, score difference, -0.44). Medical students have positive attitudes toward science and scientific method in medicine. Attendance of a course on research methodology had positive short-term effect on students' attitudes toward science. This positive effect should be maintained by vertical integration of the course in the medical curriculum.

A Comparison of Traditional and Holistic Instructional Methods in Developing Positive Attitudes Toward Mathematics Instruction in Students at Malcolm X College.

ERIC Educational Resources Information Center

Williams, Richard W.

The purpose of this study was to explore whether "holistic" instruction is an effective way to improve student attitudes toward instruction. Study participants were students in two Mathematics 111 classes at Malcolm X College (Illinois), 27 in the experimental and 27 in the control group. The experimental group received holistic…

Robust integral variable structure controller and pulse-width pulse-frequency modulated input shaper design for flexible spacecraft with mismatched uncertainty/disturbance.

PubMed

Hu, Qinglei

2007-10-01

This paper presents a dual-stage control system design method for the flexible spacecraft attitude maneuvering control by use of on-off thrusters and active vibration control by input shaper. In this design approach, attitude control system and vibration suppression were designed separately using lower order model. As a stepping stone, an integral variable structure controller with the assumption of knowing the upper bounds of the mismatched lumped perturbation has been designed which ensures exponential convergence of attitude angle and angular velocity in the presence of bounded uncertainty/disturbances. To reconstruct estimates of the system states for use in a full information variable structure control law, an asymptotic variable structure observer is also employed. In addition, the thruster output is modulated in pulse-width pulse-frequency so that the output profile is similar to the continuous control histories. For actively suppressing the induced vibration, the input shaping technique is used to modify the existing command so that less vibration will be caused by the command itself, which only requires information about the vibration frequency and damping of the closed-loop system. The rationale behind this hybrid control scheme is that the integral variable structure controller can achieve good precision pointing, even in the presence of uncertainties/disturbances, whereas the shaped input attenuator is applied to actively suppress the undesirable vibrations excited by the rapid maneuvers. Simulation results for the spacecraft model show precise attitude control and vibration suppression.

In Their Own Words: The Significance of Participant Perceptions in Assessing Entomology Citizen Science Learning Outcomes Using a Mixed Methods Approach

PubMed Central

Lynch, Louise I.; Dauer, Jenny M.; Babchuk, Wayne A.; Heng-Moss, Tiffany

2018-01-01

A mixed methods study was used to transcend the traditional pre-, post-test approach of citizen science evaluative research by integrating adults’ test scores with their perceptions. We assessed how contributory entomology citizen science affects participants’ science self-efficacy, self-efficacy for environmental action, nature relatedness and attitude towards insects. Pre- and post-test score analyses from citizen scientists (n = 28) and a control group (n = 72) were coupled with interviews (n = 11) about science experiences and entomological interactions during participation. Considering quantitative data alone, no statistically significant changes were evident in adults following participation in citizen science when compared to the control group. Citizen scientists’ pre-test scores were significantly higher than the control group for self-efficacy for environmental action, nature relatedness and attitude towards insects. Interview data reveal a notable discrepancy between measured and perceived changes. In general, citizen scientists had an existing, long-term affinity for the natural world and perceived increases in their science self-efficacy, self-efficacy for environmental action, nature relatedness and attitude towards insects. Perceived influences may act independently of test scores. Scale instruments may not show impacts with variances in individual’s prior knowledge and experiences. The value of mixed methods on citizen science program evaluation is discussed. PMID:29415522

In Their Own Words: The Significance of Participant Perceptions in Assessing Entomology Citizen Science Learning Outcomes Using a Mixed Methods Approach.

PubMed

Lynch, Louise I; Dauer, Jenny M; Babchuk, Wayne A; Heng-Moss, Tiffany; Golick, Doug

2018-02-06

A mixed methods study was used to transcend the traditional pre-, post-test approach of citizen science evaluative research by integrating adults' test scores with their perceptions. We assessed how contributory entomology citizen science affects participants' science self-efficacy, self-efficacy for environmental action, nature relatedness and attitude towards insects. Pre- and post-test score analyses from citizen scientists ( n = 28) and a control group ( n = 72) were coupled with interviews ( n = 11) about science experiences and entomological interactions during participation. Considering quantitative data alone, no statistically significant changes were evident in adults following participation in citizen science when compared to the control group. Citizen scientists' pre-test scores were significantly higher than the control group for self-efficacy for environmental action, nature relatedness and attitude towards insects. Interview data reveal a notable discrepancy between measured and perceived changes. In general, citizen scientists had an existing, long-term affinity for the natural world and perceived increases in their science self-efficacy, self-efficacy for environmental action, nature relatedness and attitude towards insects. Perceived influences may act independently of test scores. Scale instruments may not show impacts with variances in individual's prior knowledge and experiences. The value of mixed methods on citizen science program evaluation is discussed.

Predicted torque equilibrium attitude utilization for Space Station attitude control

NASA Technical Reports Server (NTRS)

Kumar, Renjith R.; Heck, Michael L.; Robertson, Brent P.

1990-01-01

An approximate knowledge of the torque equilibrium attitude (TEA) is shown to improve the performance of a control moment gyroscope (CMG) momentum management/attitude control law for Space Station Freedom. The linearized equations of motion are used in conjunction with a state transformation to obtain a control law which uses full state feedback and the predicted TEA to minimize both attitude excursions and CMG peak and secular momentum. The TEA can be computationally determined either by observing the steady state attitude of a 'controlled' spacecraft using arbitrary initial attitude, or by simulating a fixed attitude spacecraft flying in desired orbit subject to realistic environmental disturbance models.

[Evaluation of nutrition instruction in a group of Senegalese students at the secondary level].

PubMed

Sakiliba, H; Turgeon-O'brien, H; Vallières, A; Plante, J

2001-04-01

In Senegal, nutrition instruction was implanted in 1981 in the national curriculum of biology and has never been evaluated since. The purpose of this study, was to evaluate the effect of a six weeks nutrition instruction program on improving nutrition knowledge and nutrition attitudes in an experimental group including 81 subjects aged 16.7+/-1.2 years and a control group including 80 subjects aged 15.7+/-1.3 years. These subjects came respectively from third and fourth grade. A questionnaire on knowledge and one on attitudes were administered to the experimental group, before and after the nutrition instruction, while the control group, who did not received any nutrition instruction, also answered the questionnaires. Results indicate that the adjusted mean knowledge posttest scores did not significantly increase in the experimental group compared to the control group. In addition, the adjusted mean attitude postscores of the boys and girls of the experimental group on the attitude scale "Nutrition affects health" were significantly higher from that of the control group. An evaluation of the nutrition curriculum and the teaching methods is suggested in order to improve the effectiveness of this nutrition program.

The Effectiveness of the Barton's Intervention Program on Reading Comprehension and Reading Attitude of Students with Dyslexia.

PubMed

Mihandoost, Zeinab; Elias, Habibah

2011-01-01

The current research tested the differences in reading attitude and reading comprehension in the dyslexic students between the control group and the experimental group following the Barton intervention program. Dyslexia screening instrument and reading text were employed in order to identify dyslexic students. The population of the study included 138 dyslexic students studying in schools in Ilam, Iran. From this population, 64 students were randomly selected and assigned to an experimental group as well as a control group. The experimental group was taught for 36 sessions, using the Barton's method at two levels, and ten lessons were provided to improve the reading skill. The reading comprehension and reading attitude instruments were employed for the measurement of the attitude and comprehension before and after the intervention program. The analysis of covariance showed a significant difference between the control group and the experimental group following the Barton intervention program. This study showed that dyslexic students learned to read, and a more direct instruction related to decoding could influence their progress more than the general exposure to education.

Spacecraft Attitude Tracking and Maneuver Using Combined Magnetic Actuators

NASA Technical Reports Server (NTRS)

Zhou, Zhiqiang

2010-01-01

The accuracy of spacecraft attitude control using magnetic actuators only is low and on the order of 0.4-5 degrees. The key reason is that the magnetic torque is two-dimensional and it is only in the plane perpendicular to the magnetic field vector. In this paper novel attitude control algorithms using the combination of magnetic actuators with Reaction Wheel Assembles (RWAs) or other types of actuators, such as thrusters, are presented. The combination of magnetic actuators with one or two RWAs aligned with different body axis expands the two-dimensional control torque to three-dimensional. The algorithms can guarantee the spacecraft attitude and rates to track the commanded attitude precisely. A design example is presented for Nadir pointing, pitch and yaw maneuvers. The results show that precise attitude tracking can be reached and the attitude control accuracy is comparable with RWAs based attitude control. The algorithms are also useful for the RWAs based attitude control. When there are only one or two workable RWAs due to RWA failures, the attitude control system can switch to the control algorithms for the combined magnetic actuators with the RWAs without going to the safe mode and the control accuracy can be maintained.

Advantages of estimating rate corrections during dynamic propagation of spacecraft rates: Applications to real-time attitude determination of SAMPEX

NASA Technical Reports Server (NTRS)

Challa, M. S.; Natanson, G. A.; Baker, D. F.; Deutschmann, J. K.

1994-01-01

This paper describes real-time attitude determination results for the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX), a gyroless spacecraft, using a Kalman filter/Euler equation approach denoted the real-time sequential filter (RTSF). The RTSF is an extended Kalman filter whose state vector includes the attitude quaternion and corrections to the rates, which are modeled as Markov processes with small time constants. The rate corrections impart a significant robustness to the RTSF against errors in modeling the environmental and control torques, as well as errors in the initial attitude and rates, while maintaining a small state vector. SAMPLEX flight data from various mission phases are used to demonstrate the robustness of the RTSF against a priori attitude and rate errors of up to 90 deg and 0.5 deg/sec, respectively, as well as a sensitivity of 0.0003 deg/sec in estimating rate corrections in torque computations. In contrast, it is shown that the RTSF attitude estimates without the rate corrections can degrade rapidly. RTSF advantages over single-frame attitude determination algorithms are also demonstrated through (1) substantial improvements in attitude solutions during sun-magnetic field coalignment and (2) magnetic-field-only attitude and rate estimation during the spacecraft's sun-acquisition mode. A robust magnetometer-only attitude-and-rate determination method is also developed to provide for the contingency when both sun data as well as a priori knowledge of the spacecraft state are unavailable. This method includes a deterministic algorithm used to initialize the RTSF with coarse estimates of the spacecraft attitude and rates. The combined algorithm has been found effective, yielding accuracies of 1.5 deg in attitude and 0.01 deg/sec in the rates and convergence times as little as 400 sec.

Guidance and control 1992; Proceedings of the 15th Annual AAS Rocky Mountain Conference, Keystone, CO, Feb. 8-12, 1992

NASA Astrophysics Data System (ADS)

Culp, Robert D.; Zietz, Richard P.

The present volume on guidance and control discusses advances in guidance, navigation, and control, guidance and control storyboard displays, space robotic control, spacecraft control and flexible body interaction, and the Mission to Planet Earth. Attention is given to applications of Newton's method to attitude determination, a new family of low-cost momentum/reaction wheels, stellar attitude data handling, and satellite life prediction using propellant quantity measurements. Topics addressed include robust manipulator controller specification and design, implementations and applications of a manipulator control testbed, optimizing transparency in teleoperator architectures, and MIMO system identification using frequency response data. Also discussed are instrument configurations for the restructured Earth Observing System, the HIRIS instrument, clouds and the earth's radiant energy system, and large space-based systems for dealing with global change.

Three-Axis Attitude Control of Solar Sails Utilising Reflectivity Control Devices

NASA Astrophysics Data System (ADS)

Theodorou, Theodoros

Solar sails are spacecraft that utilise the Solar Radiation Pressure, the force generated by impinging photons, to propel themselves. Conventional actuators are not suitable for controlling the attitude of solar sails therefore specific attitude control methods have been devised to tackle this. One of these methods is to change the centre of pressure with respect to the center of mass thus creating a torque. Reflectivity Control Devices (RCDs) have been proposed and successfully used to change the centre of pressure. Current methods that utilise RCDs have control authority over two axis only with no ability to control the torque about the normal of the sail surface. This thesis extends the state of the art and demonstrates 3-axis control by generating arbitrary torque vectors within a convex polyhedron. Two different RCD materials are considered, transmission and diffusion technologies both compatible with the proposed concept. A number of metrics have been developed which facilitate the comparison of different sail configurations. One of these metics is the sun map which is a graphic representation of the sun angles for which control authority is maintained. An iterative design process is presented which makes use of the metrics developed and aids in the design of a sail which meets the mission requirements and constraints. Moreover, the effects of different parameters on the performance of the proposed control concept are discussed. For example it is shown that by alternating the angle between the edge and middle RCDs the control authority increases. The concept's scalability has been investigated and a hybrid control scheme has been devised which makes use of both RCDs and reaction wheels. The RCDs are complemented by the reaction wheels to achieve higher slew rates while in turn the RCDs desaturate the reaction wheels. Finally, a number of simulations are conducted to verify the validity of the proposed concept.

[Development and Effects of a Children's Sex Education Program for the Parents of Lower Elementary Grade Students].

PubMed

Lee, Eun Mi; Kim, Hyunlye

2017-04-01

This study was done to develop a children's sex education program for the parents of lower elementary grade students and to evaluate its effects on sexual knowledge, gender role attitude, parent efficacy for child's sex education, and marital consistency. A quasi-experimental with a non-equivalent control group pretest-posttest design was used. The participants were 29 couples (58 parents, experimental group=28, control group=30) from G city. The 5-week (5-session) program was developed based on 'A theory of protection: parents as sex educators' and used the case-based small group learning method. Data were collected during July and August 2015. The characteristics of the program developed in the present study were a theoretical-based, client-centered, multi-method. After the intervention, the experimental group showed a significant improvement in sexual knowledge, gender role attitudes, parent efficacy for child's sex education, and marital consistency, compared to the control group. The effect sizes of the program were .64 (knowledge), .65 (gender role attitudes), and .68 (parent efficacy). The results of this study provided implications for the parents as effective sex educator and the role expansion of school health nurses. © 2017 Korean Society of Nursing Science

Linearizing feedforward/feedback attitude control

NASA Technical Reports Server (NTRS)

Paielli, Russell A.; Bach, Ralph E.

1991-01-01

An approach to attitude control theory is introduced in which a linear form is postulated for the closed-loop rotation error dynamics, then the exact control law required to realize it is derived. The nonminimal (four-component) quaternion form is used to attitude because it is globally nonsingular, but the minimal (three-component) quaternion form is used for attitude error because it has no nonlinear constraints to prevent the rotational error dynamics from being linearized, and the definition of the attitude error is based on quaternion algebra. This approach produces an attitude control law that linearizes the closed-loop rotational error dynamics exactly, without any attitude singularities, even if the control errors become large.

Instructional multimedia: an investigation of student and instructor attitudes and student study behavior.

PubMed

Smith, A Russell; Cavanaugh, Cathy; Moore, W Allen

2011-06-21

Educators in allied health and medical education programs utilize instructional multimedia to facilitate psychomotor skill acquisition in students. This study examines the effects of instructional multimedia on student and instructor attitudes and student study behavior. Subjects consisted of 45 student physical therapists from two universities. Two skill sets were taught during the course of the study. Skill set one consisted of knee examination techniques and skill set two consisted of ankle/foot examination techniques. For each skill set, subjects were randomly assigned to either a control group or an experimental group. The control group was taught with live demonstration of the examination skills, while the experimental group was taught using multimedia. A cross-over design was utilized so that subjects in the control group for skill set one served as the experimental group for skill set two, and vice versa. During the last week of the study, students and instructors completed written questionnaires to assess attitude toward teaching methods, and students answered questions regarding study behavior. There were no differences between the two instructional groups in attitudes, but students in the experimental group for skill set two reported greater study time alone compared to other groups. Multimedia provides an efficient method to teach psychomotor skills to students entering the health professions. Both students and instructors identified advantages and disadvantages for both instructional techniques. Reponses relative to instructional multimedia emphasized efficiency, processing level, autonomy, and detail of instruction compared to live presentation. Students and instructors identified conflicting views of instructional detail and control of the content.

The Effect of Guided-Inquiry Instruction on 6th Grade Turkish Students' Achievement, Science Process Skills, and Attitudes Toward Science

NASA Astrophysics Data System (ADS)

Koksal, Ela Ayse; Berberoglu, Giray

2014-01-01

The purpose of this study is to investigate the effectiveness of guided-inquiry approach in science classes over existing science and technology curriculum in developing content-based science achievement, science process skills, and attitude toward science of grade level 6 students in Turkey. Non-equivalent control group quasi-experimental design was used to investigate the treatment effect. There were 162 students in the experimental group and 142 students in the control group. Both the experimental and control group students took the Achievement Test in Reproduction, Development, and Growth in Living Things (RDGLT), Science Process Skills Test, and Attitudes Toward Science Questionnaire, as pre-test and post-test. Repeated analysis of variance design was used in analyzing the data. Both the experimental and control group students were taught in RDGLT units for 22 class hours. The results indicated the positive effect of guided-inquiry approach on the Turkish students' cognitive as well as affective characteristics. The guided inquiry enhanced the experimental group students' understandings of the science concepts as well as the inquiry skills more than the control group students. Similarly, the experimental group students improved their attitudes toward science more than the control group students as a result of treatment. The guided inquiry seems a transition between traditional teaching method and student-centred activities in the Turkish schools.

Space construction base control system

NASA Technical Reports Server (NTRS)

Kaczynski, R. F.

1979-01-01

Several approaches for an attitude control system are studied and developed for a large space construction base that is structurally flexible. Digital simulations were obtained using the following techniques: (1) the multivariable Nyquist array method combined with closed loop pole allocation, (2) the linear quadratic regulator method. Equations for the three-axis simulation using the multilevel control method were generated and are presented. Several alternate control approaches are also described. A technique is demonstrated for obtaining the dynamic structural properties of a vehicle which is constructed of two or more submodules of known dynamic characteristics.

The dynamics and control of large flexible space structures, 3. Part A: Shape and orientation control of a platform in orbit using point actuators

NASA Technical Reports Server (NTRS)

Bainum, P. M.; Reddy, A. S. S. R.; Krishna, R.; James, P. K.

1980-01-01

The dynamics, attitude, and shape control of a large thin flexible square platform in orbit are studied. Attitude and shape control are assumed to result from actuators placed perpendicular to the main surface and one edge and their effect on the rigid body and elastic modes is modelled to first order. The equations of motion are linearized about three different nominal orientations: (1) the platform following the local vertical with its major surface perpendicular to the orbital plane; (2) the platform following the local horizontal with its major surface normal to the local vertical; and (3) the platform following the local vertical with its major surface perpendicular to the orbit normal. The stability of the uncontrolled system is investigated analytically. Once controllability is established for a set of actuator locations, control law development is based on decoupling, pole placement, and linear optimal control theory. Frequencies and elastic modal shape functions are obtained using a finite element computer algorithm, two different approximate analytical methods, and the results of the three methods compared.

Seasat-A attitude control system

NASA Technical Reports Server (NTRS)

Weiss, R.; Rodden, J. J.; Hendricks, R. J.

1977-01-01

The Seasat-A attitude control system controls the attitude of the satellite system during injection into final circular orbit after Atlas boost, during orbit adjust and trim phases, and throughout the 3-year mission. Ascent and injection guidance and attitude control are provided by the Agena spacecraft with a gyrocompassed mass expulsion system. On-orbit attitude control functions are performed by a system that has its functional roots in the gravity-gradient momentum bias technology. The paper discusses hardware, control laws, and simulation results.

14 CFR 125.225 - Flight data recorders.

Code of Federal Regulations, 2014 CFR

2014-01-01

... acceleration; (5) Heading; (6) Time of each radio transmission to or from air traffic control; (7) Pitch attitude; (8) Roll attitude; (9) Longitudinal acceleration; (10) Control column or pitch control surface... control; (7) Pitch attitude; (8) Roll attitude; (9) Longitudinal acceleration; (10) Pitch trim position...

Robust fault-tolerant tracking control design for spacecraft under control input saturation.

PubMed

Bustan, Danyal; Pariz, Naser; Sani, Seyyed Kamal Hosseini

2014-07-01

In this paper, a continuous globally stable tracking control algorithm is proposed for a spacecraft in the presence of unknown actuator failure, control input saturation, uncertainty in inertial matrix and external disturbances. The design method is based on variable structure control and has the following properties: (1) fast and accurate response in the presence of bounded disturbances; (2) robust to the partial loss of actuator effectiveness; (3) explicit consideration of control input saturation; and (4) robust to uncertainty in inertial matrix. In contrast to traditional fault-tolerant control methods, the proposed controller does not require knowledge of the actuator faults and is implemented without explicit fault detection and isolation processes. In the proposed controller a single parameter is adjusted dynamically in such a way that it is possible to prove that both attitude and angular velocity errors will tend to zero asymptotically. The stability proof is based on a Lyapunov analysis and the properties of the singularity free quaternion representation of spacecraft dynamics. Results of numerical simulations state that the proposed controller is successful in achieving high attitude performance in the presence of external disturbances, actuator failures, and control input saturation. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Chaos as the hub of systems dynamics. The part I-The attitude control of spacecraft by involving in the heteroclinic chaos

NASA Astrophysics Data System (ADS)

Doroshin, Anton V.

2018-06-01

In this work the chaos in dynamical systems is considered as a positive aspect of dynamical behavior which can be applied to change systems dynamical parameters and, moreover, to change systems qualitative properties. From this point of view, the chaos can be characterized as a hub for the system dynamical regimes, because it allows to interconnect separated zones of the phase space of the system, and to fulfill the jump into the desirable phase space zone. The concretized aim of this part of the research is to focus on developing the attitude control method for magnetized gyrostat-satellites, which uses the passage through the intentionally generated heteroclinic chaos. The attitude dynamics of the satellite/spacecraft in this case represents the series of transitions from the initial dynamical regime into the chaotic heteroclinic regime with the subsequent exit to the final target dynamical regime with desirable parameters of the attitude dynamics.

Maternal attitudes toward DNA collection for gene-environment studies: a qualitative research study.

PubMed

Jenkins, Mary M; Reed-Gross, Erika; Rasmussen, Sonja A; Barfield, Wanda D; Prue, Christine E; Gallagher, Margaret L; Honein, Margaret A

2009-11-01

To assess attitudes toward DNA collection in an epidemiological study, focus groups were assembled in September 2007 with mothers who had participated in a case-control study of birth defects. Each recruited mother previously had completed an interview and had received a mailed kit containing cytobrushes to collect buccal cells for DNA from herself, her infant, and her infant's father during the period July 2004 through July 2007. A total of 38 mothers attended six focus groups comprising: (1) non-Hispanic Black mothers of case infants who participated or (2) did not participate in DNA collection, (3) mothers of any race or ethnicity who had case infants of low birth weight who participated or (4) did not participate in DNA collection, and (5) non-Hispanic Black mothers of control infants who participated or (6) did not participate in DNA collection. Moderator-led discussions probed maternal attitudes toward providing specimens, factors that influenced decision making, and collection method preferences. Biologics participants reported that they provided DNA for altruistic reasons. Biologics nonparticipants voiced concerns about government involvement and how their DNA will be used. Information provided (or not provided) on DNA use, storage, and disposal influenced decision making. Biologics participants and nonparticipants reported that paternal skepticism was a barrier to participation. All mothers were asked to rank DNA collection methods in terms of preference (cytobrushes, saliva, mouthwash, newborn blood spots, and blood collection). Preferred methods were convenient and noninvasive. Better understanding attitudes toward DNA collection and preferred collection methods might allow more inclusive participation and benefit future studies. Copyright 2009 Wiley-Liss, Inc.

Optimization of Closed Loop Eigenvalues: Maneuvering, Vibration Control, and Structure/Control Design Iteration for Flexible Spacecraft.

DTIC Science & Technology

1986-05-31

Nonlinear Feedback Control 8-16 for Spacecraft Attitude Maneuvers" 2. " Spacecraft Attitude Control Using 17-35... nonlinear state feedback control laws are developed for space- craft attitude control using the Euler parameters and conjugate angular momenta. Time... Nonlinear Feedback Control for Spacecraft Attitude Maneuvers," to appear in AIAA J. of Guidance, Control, and Dynamics, (AIAA Paper No. 83-2230-CP,

A simple orbit-attitude coupled modelling method for large solar power satellites

NASA Astrophysics Data System (ADS)

Li, Qingjun; Wang, Bo; Deng, Zichen; Ouyang, Huajiang; Wei, Yi

2018-04-01

A simple modelling method is proposed to study the orbit-attitude coupled dynamics of large solar power satellites based on natural coordinate formulation. The generalized coordinates are composed of Cartesian coordinates of two points and Cartesian components of two unitary vectors instead of Euler angles and angular velocities, which is the reason for its simplicity. Firstly, in order to develop natural coordinate formulation to take gravitational force and gravity gradient torque of a rigid body into account, Taylor series expansion is adopted to approximate the gravitational potential energy. The equations of motion are constructed through constrained Hamilton's equations. Then, an energy- and constraint-conserving algorithm is presented to solve the differential-algebraic equations. Finally, the proposed method is applied to simulate the orbit-attitude coupled dynamics and control of a large solar power satellite considering gravity gradient torque and solar radiation pressure. This method is also applicable to dynamic modelling of other rigid multibody aerospace systems.

Transition clinic attendance is associated with improved beliefs and attitudes toward medicine in patients with inflammatory bowel disease

PubMed Central

Fu, Nancy; Jacobson, Kevan; Round, Andrew; Evans, Kathi; Qian, Hong; Bressler, Brian

2017-01-01

AIM To evaluated the differences in knowledge, adherence, attitudes, and beliefs about medicine in adolescents with inflammatory bowel disease (IBD) attending transition clinics. METHODS We prospectively enrolled patients from July 2012 to June 2013. All adolescents who attended a tertiary-centre-based dedicated IBD transition clinic were invited to participate. Adolescent controls were recruited from university-affiliated gastroenterology offices. Participants completed questionnaires about their disease and reported adherence to prescribed therapy. Beliefs in Medicine Questionnaire was used to evaluate patients’ attitudes and beliefs. Beliefs of medication overuse, harm, necessity and concerns were rated on a Likert scale. Based on necessity and concern ratings, attitudes were then characterized as accepting, ambivalent, skeptical and indifferent. RESULTS One hundred and twelve adolescents were included and 59 attended transition clinics. Self-reported adherence rates were poor, with only 67.4% and 56.8% of patients on any IBD medication were adherent in the transition and control groups, respectively. Adolescents in the transition cohort held significantly stronger beliefs that medications were necessary (P = 0.0035). Approximately 20% of adolescents in both cohorts had accepting attitudes toward their prescribed medicine. However, compared to the control group, adolescents in the transition cohort were less skeptical of (6.8% vs 20.8%) and more ambivalent (61% vs 34%) (OR = 0.15; 95%CI: 0.03-0.75; P = 0.02) to treatment. CONCLUSION Attendance at dedicated transition clinics was associated with differences in attitudes in adolescents with IBD. PMID:28839441

An examination of student attitudes and understanding of exponential functions using interactive instructional multimedia

NASA Astrophysics Data System (ADS)

Singleton, Cynthia M.

The purpose of this study was to examine students' attitudes and understanding of exponential functions using InterAct Math, a mathematics tutorial software. The researcher used a convenience sampling of a total of 78 students from two intact pre-calculus classes; the students in the experimental group totaled 41 and the control group totaled 37. The two groups were exposed to the same curriculum content taught by the same instructor, the researcher. The experimental group used the mathematics tutorial software as an integral part of the instructional delivery. The control group used traditional instruction without integration of the educational technology. Data were collected during a two week span using a mixed-methodology to address the major research questions: (1) Is there a statistically significant difference in the mean achievement test scores between the experimental and the control groups? (2) Is there a statistically significant difference in students' attitudes toward learning mathematics between the experimental group and the control group? The researcher utilized paired t-tests and independent t-tests as statistical methods to evaluate the effectiveness of the intervention and to establish whether there was a significant difference between the experimental and control groups. Based on the analyses of the quantitative data, it was established that the students who received the InterAct Math tutorial (experimental group) did not perform better than the control group on exponential functions, graphs and applications. However, the quantitative part of the study (Aiken-Dreger Mathematics Attitude Scale) revealed that, while students in the experimental and control groups started with similar attitudes about mathematics and the integration of technology, their attitudes were significantly different at the conclusion of the study. The fear of mathematics was reduced for the experimental group at the end of the study, and their enjoyment of the subject matter was increased as a result of the intervention. No significant difference was reported concerning attitudes toward fear and enjoyment of learning mathematics for the control group. The researcher concluded that the use of InterAct Math tutorial software as part of the instructional delivery was beneficial and contributed to a positive attitude change. Other qualitative data obtained from the unstructured interviews of the treatment group supported these findings and reported that the change in attitudes was attributable to the use of the InterAct software in the instructional delivery of the course. The researcher concluded that the results of the study did not provide evidence that InterAct Math software could be credited with producing better learning outcomes. However, it appears that the InterAct Math tutorial software is an effective tutorial tool in promoting positive change in students' attitudes toward learning mathematics; thus, it is an effective tool for mathematics instruction. Based on the above results, it was concluded that the InterAct Math tutorial is an effective tutorial tool in promoting positive attitude change in students toward learning mathematics.

Integral sliding mode-based attitude coordinated tracking for spacecraft formation with communication delays

NASA Astrophysics Data System (ADS)

Zhang, Jian; Hu, Qinglei; Xie, Wenbo

2017-11-01

This paper investigates the attitude coordinated tracking control for a group of rigid spacecraft under directed communication topology, in which inertia uncertainties, external disturbances, input saturation and constant time-delays between the formation members are handled. Initially, the nominal system with communication delays is studied. A delay-dependent controller is proposed by using Lyapunov-Krasovskii function and sufficient condition for system stability is derived. Then, an integral sliding manifold is designed and adaptive control approach is employed to deal with the total perturbation. Meanwhile, the boundary layer method is introduced to alleviate the unexpected chattering as system trajectories cross the switching surface. Finally, numerical simulation results are presented to validate the effectiveness and robustness of the proposed control strategy.

Attributions and Attitudes of Mothers and Fathers in Jordan.

PubMed

Al-Hassan, Suha; Takash, Hanan

2011-07-01

OBJECTIVE: The present study examined mean level similarities and differences as well as correlations between mothers' and fathers' attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes in Jordan. DESIGN: Interviews were conducted with both mothers and fathers in 112 families. RESULTS: There were no significant main effects of gender on any of the constructs of interest. Mothers and fathers reported similar levels of attributions regarding uncontrollable success, adult-controlled failure, and child-controlled failure in the same family. Regarding attitudes, mothers and fathers reported greater progressive attitudes than authoritarian attitudes. Large, significant correlations were found for concordance between parents in the same family on all seven attributions and attitudes examined; all remained significant after controlling for parents' age, education, and possible social desirability bias. Significant positive correlations were found for mothers' and fathers' attributions regarding uncontrollable success, adult-controlled failure, child-controlled failure, perceived control over failure, progressive attitudes, authoritarian attitudes, and modernity of attitudes. CONCLUSIONS: This study concluded that in Jordan mothers and fathers hold similar levels of attributions and attitudes.

The effect on prospective teachers of the learning environment supported by dynamic statistics software

NASA Astrophysics Data System (ADS)

Koparan, Timur

2016-02-01

In this study, the effect on the achievement and attitudes of prospective teachers is examined. With this aim ahead, achievement test, attitude scale for statistics and interviews were used as data collection tools. The achievement test comprises 8 problems based on statistical data, and the attitude scale comprises 13 Likert-type items. The study was carried out in 2014-2015 academic year fall semester at a university in Turkey. The study, which employed the pre-test-post-test control group design of quasi-experimental research method, was carried out on a group of 80 prospective teachers, 40 in the control group and 40 in the experimental group. Both groups had four-hour classes about descriptive statistics. The classes with the control group were carried out through traditional methods while dynamic statistics software was used in the experimental group. Five prospective teachers from the experimental group were interviewed clinically after the application for a deeper examination of their views about application. Qualitative data gained are presented under various themes. At the end of the study, it was found that there is a significant difference in favour of the experimental group in terms of achievement and attitudes, the prospective teachers have affirmative approach to the use of dynamic software and see it as an effective tool to enrich maths classes. In accordance with the findings of the study, it is suggested that dynamic software, which offers unique opportunities, be used in classes by teachers and students.

Fuzzy attitude control of solar sail via linear matrix inequalities

NASA Astrophysics Data System (ADS)

Baculi, Joshua; Ayoubi, Mohammad A.

2017-09-01

This study presents a fuzzy tracking controller based on the Takagi-Sugeno (T-S) fuzzy model of the solar sail. First, the T-S fuzzy model is constructed by linearizing the existing nonlinear equations of motion of the solar sail. Then, the T-S fuzzy model is used to derive the state feedback controller gains for the Twin Parallel Distributed Compensation (TPDC) technique. The TPDC tracks and stabilizes the attitude of the solar sail to any desired state in the presence of parameter uncertainties and external disturbances while satisfying actuator constraints. The performance of the TPDC is compared to a PID controller that is tuned using the Ziegler-Nichols method. Numerical simulation shows the TPDC outperforms the PID controller when stabilizing the solar sail to a desired state.

Aerial cooperative transporting and assembling control using multiple quadrotor-manipulator systems

NASA Astrophysics Data System (ADS)

Qi, Yuhua; Wang, Jianan; Shan, Jiayuan

2018-02-01

In this paper, a fully distributed control scheme for aerial cooperative transporting and assembling is proposed using multiple quadrotor-manipulator systems with each quadrotor equipped with a robotic manipulator. First, the kinematic and dynamic models of a quadrotor with multi-Degree of Freedom (DOF) robotic manipulator are established together using Euler-Lagrange equations. Based on the aggregated dynamic model, the control scheme consisting of position controller, attitude controller and manipulator controller is presented. Regarding cooperative transporting and assembling, multiple quadrotor-manipulator systems should be able to form a desired formation without collision among quadrotors from any initial position. The desired formation is achieved by the distributed position controller and attitude controller, while the collision avoidance is guaranteed by an artificial potential function method. Then, the transporting and assembling tasks request the manipulators to reach the desired angles cooperatively, which is achieved by the distributed manipulator controller. The overall stability of the closed-loop system is proven by a Lyapunov method and Matrosov's theorem. In the end, the proposed control scheme is simplified for the real application and then validated by two formation flying missions of four quadrotors with 2-DOF manipulators.

Changes in sunburn and tanning attitudes among lifeguards over a summer season

PubMed Central

Hiemstra, Marieke; Glanz, Karen; Nehl, Eric

2013-01-01

Background Skin cancer is one of the most common cancers in the United States. Lifeguards are at increased risk of excessive sun exposure and sunburn. Objectives We sought to examine changes in: (1) sunburn frequency over a summer while controlling for sun exposure, sun protection habits, and participation in a skin cancer prevention program; and (2) tanning attitudes while controlling for participation in the program. Methods Participants in this study were lifeguards (n = 3014) at swimming pools participating in the Pool Cool program in 2005. Lifeguards completed surveys at the beginning and end of the summer. Sequential regression analyses were used to assess changes in sunburn frequency and tanning attitudes. Results Sunburn frequency decreased between baseline and follow-up. Having a sunburn over the summer was significantly predicted by baseline sunburn history, ethnicity, skin cancer risk, and sun exposure. The tanning attitude, “People are more attractive if they have a tan,” was significantly predicted from baseline tanning attitude and ethnicity. The second tanning attitude, “It helps to have a good base suntan,” was significantly predicted by baseline tanning attitude, ethnicity, basic/enhanced group, and moderate skin cancer risk. Limitations Self-reported data and limited generalizability to lifeguards at other outdoor pools are limitations. Conclusion The findings showed that previous sunburn history is an important predictor of sunburn prospectively. In addition, a more risky tanning attitude is an important predictor of future attitudes toward tanning. Active involvement in targeted prevention programs may help to increase preventive behavior and health risk reduction. PMID:21745696

[Cancer nursing care education programs: the effectiveness of different teaching methods].

PubMed

Cheng, Yun-Ju; Kao, Yu-Hsiu

2012-10-01

In-service education affects the quality of cancer care directly. Using classroom teaching to deliver in-service education is often ineffective due to participants' large workload and shift requirements. This study evaluated the learning effectiveness of different teaching methods in the dimensions of knowledge, attitude, and learning satisfaction. This study used a quasi-experimental study design. Participants were cancer ward nurses working at one medical center in northern Taiwan. Participants were divided into an experimental group and control group. The experimental group took an e-learning course and the control group took a standard classroom course using the same basic course material. Researchers evaluated the learning efficacy of each group using a questionnaire based on the quality of cancer nursing care learning effectiveness scale. All participants answered the questionnaire once before and once after completing the course. (1) Post-test "knowledge" scores for both groups were significantly higher than pre-test scores for both groups. Post-test "attitude" scores were significantly higher for the control group, while the experimental group reported no significant change. (2) after a covariance analysis of the pre-test scores for both groups, the post-test score for the experimental group was significantly lower than the control group in the knowledge dimension. Post-test scores did not differ significantly from pre-test scores for either group in the attitude dimension. (3) Post-test satisfaction scores between the two groups did not differ significantly with regard to teaching methods. The e-learning method, however, was demonstrated as more flexible than the classroom teaching method. Study results demonstrate the importance of employing a variety of teaching methods to instruct clinical nursing staff. We suggest that both classroom teaching and e-learning instruction methods be used to enhance the quality of cancer nursing care education programs. We also encourage that interactivity between student and instructor be incorporated into e-learning course designs to enhance effectiveness.

Neural network-based distributed attitude coordination control for spacecraft formation flying with input saturation.

PubMed

Zou, An-Min; Kumar, Krishna Dev

2012-07-01

This brief considers the attitude coordination control problem for spacecraft formation flying when only a subset of the group members has access to the common reference attitude. A quaternion-based distributed attitude coordination control scheme is proposed with consideration of the input saturation and with the aid of the sliding-mode observer, separation principle theorem, Chebyshev neural networks, smooth projection algorithm, and robust control technique. Using graph theory and a Lyapunov-based approach, it is shown that the distributed controller can guarantee the attitude of all spacecraft to converge to a common time-varying reference attitude when the reference attitude is available only to a portion of the group of spacecraft. Numerical simulations are presented to demonstrate the performance of the proposed distributed controller.

Application of matrix singular value properties for evaluating gain and phase margins of multiloop systems. [stability margins for wing flutter suppression and drone lateral attitude control

NASA Technical Reports Server (NTRS)

Mukhopadhyay, V.; Newsom, J. R.

1982-01-01

A stability margin evaluation method in terms of simultaneous gain and phase changes in all loops of a multiloop system is presented. A universal gain-phase margin evaluation diagram is constructed by generalizing an existing method using matrix singular value properties. Using this diagram and computing the minimum singular value of the system return difference matrix over the operating frequency range, regions of guaranteed stability margins can be obtained. Singular values are computed for a wing flutter suppression and a drone lateral attitude control problem. The numerical results indicate that this method predicts quite conservative stability margins. In the second example if the eigenvalue magnitude is used instead of the singular value, as a measure of nearness to singularity, more realistic stability margins are obtained. However, this relaxed measure generally cannot guarantee global stability.

Older African American Homeless-Experienced Smokers’ Attitudes Toward Tobacco Control Policies—Results from the HOPE HOME Study

PubMed Central

Vijayaraghavan, Maya; Olsen, Pamela; Weeks, John; McKelvey, Karma; Ponath, Claudia; Kushel, Margot

2018-01-01

Purpose To examine attitudes toward tobacco control policies among older African American homeless-experienced smokers. Approach A qualitative study. Setting Oakland, California. Participants Twenty-two African American older homeless-experienced smokers who were part of a longitudinal study on health and health-related outcomes (Health Outcomes of People Experiencing Homelessness in Older Middle Age Study). Method We conducted in-depth, semistructured interviews with each participant to explore beliefs and attitudes toward tobacco use and cessation, barriers to smoking cessation, and attitudes toward current tobacco control strategies including raising cigarette prices, smoke-free policies, and graphic warning labels. We used a grounded theory approach to analyze the transcripts. Results Community social norms supportive of cigarette smoking and co-use of tobacco with other illicit substances were strong motivators of initiation and maintenance of tobacco use. Self-reported barriers to cessation included nicotine dependence, the experience of being homeless, fatalistic attitudes toward smoking cessation, substance use, and exposure to tobacco industry marketing. While participants were cognizant of current tobacco control policies and interventions for cessation, they felt that they were not specific enough for African Americans experiencing homelessness. Participants expressed strong support for strategies that de-normalized tobacco use and advertised the harmful effects of tobacco. Conclusion Older African American homeless-experienced smokers face significant barriers to smoking cessation. Interventions that advertise the harmful effects of tobacco may be effective in stimulating smoking cessation among this population. PMID:28893086

Full quaternion based finite-time cascade attitude control approach via pulse modulation synthesis for a spacecraft.

PubMed

Mazinan, A H; Pasand, M; Soltani, B

2015-09-01

In the aspect of further development of investigations in the area of spacecraft modeling and analysis of the control scheme, a new hybrid finite-time robust three-axis cascade attitude control approach is proposed via pulse modulation synthesis. The full quaternion based control approach proposed here is organized in association with both the inner and the outer closed loops. It is shown that the inner closed loop, which consists of the sliding mode finite-time control approach, the pulse width pulse frequency modulator, the control allocation and finally the dynamics of the spacecraft is realized to track the three-axis referenced commands of the angular velocities. The pulse width pulse frequency modulators are in fact employed in the inner closed loop to accommodate the control signals to a number of on-off thrusters, while the control allocation algorithm provides the commanded firing times for the reaction control thrusters in the overactuated spacecraft. Hereinafter, the outer closed loop, which consists of the proportional linear control approach and the kinematics of the spacecraft is correspondingly designed to deal with the attitude angles that are presented by quaternion vector. It should be noted that the main motivation of the present research is to realize a hybrid control method by using linear and nonlinear terms and to provide a reliable and robust control structure, which is able to track time varying three-axis referenced commands. Subsequently, a stability analysis is presented to verify the performance of the overall proposed cascade attitude control approach. To prove the effectiveness of the presented approach, a thorough investigation is presented compared to a number of recent corresponding benchmarks. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

A Multilingual Mass Communication Intervention for Seniors and People with Disabilities on Medicaid: A Randomized Controlled Trial

PubMed Central

Kurtovich, Elaine; Ivey, Susan L; Neuhauser, Linda; Graham, Carrie; Constantine, Wendy; Barkan, Howard

2010-01-01

Objectives To evaluate the following: (1) baseline knowledge, attitudes, and behavioral intentions about Medicaid managed care (MMC) among seniors and people with disabilities (SPD) receiving Medicaid benefits; (2) SPD Medicaid beneficiaries' use of and satisfaction with a user-designed MMC guidebook; and (3) guidebook effects on changes in MMC knowledge, attitudes, and intended behaviors of SPD beneficiaries. Data Sources/Study Setting Survey data collected between February and May 2008 from a random sample of SPD receiving Medicaid benefits in three California counties. Study Design This randomized controlled trial of 319 intervention and 373 control SPD Medicaid beneficiaries used pre- and postintervention telephone surveys to compare changes in MMC knowledge, attitudes, and intended behaviors. Data Collection Methods Baseline and follow-up telephone interviews were conducted in English, Spanish, Cantonese, and Mandarin. Principal Findings Seventy-seven percent of intervention participants reported using the guidebook. Nearly all (97.9 percent) found it somewhat or very useful. Intervention participants showed gains in knowledge, positive attitudes, and intentions to enroll in MMC that are statistically significant compared with control participants. However, knowledge levels remained low even among intervention participants. Conclusions Findings suggest that the guidebook is an effective way to improve recipients' MMC knowledge, confidence, and behavioral intentions. PMID:20070389

Are Anti-Stigma Films a Useful Strategy for Reducing Weight Bias Among Trainee Healthcare Professionals? Results of a Pilot Randomized Control Trial

PubMed Central

Swift, Judy Anne; Tischler, Victoria; Markham, Sophie; Gunning, Ingrid; Glazebrook, Cris; Beer, Charlotte; Puhl, Rebecca

2013-01-01

Background Weight bias is an important clinical issue that the educators of tomorrow's healthcare professionals cannot afford to ignore. This study, therefore, aimed to pilot a randomized controlled trial of the effects of educational films designed to reduce weight stigmatization toward obese patients on trainee dietitians’ and doctors’ attitudes. Methods A pre-post experimental design with a 6-week follow-up, which consisted of an intervention group (n = 22) and a control group (n = 21), was conducted to assess the efficacy of brief anti-stigma films in reducing weight bias, and to test whether future, larger-scale studies among trainee healthcare professionals are feasible. Results Participants at baseline demonstrated weight bias, on both implicit and explicit attitude measures, as well as strong beliefs that obesity is under a person's control. The intervention films significantly improved explicit attitudes and beliefs toward obese people, and participant evaluation was very positive. The intervention did not significantly improve implicit anti-fat bias. Conclusion The current study suggests both that it is possible to conduct a substantive trial of the effects of educational films designed to reduce weight stigma on a larger cohort of trainee healthcare professionals, and that brief educational interventions may be effective in reducing stigmatizing attitudes in this population. PMID:23466551

The effects of contextual learning instruction on science achievement of male and female tenth-grade students

NASA Astrophysics Data System (ADS)

Ingram, Samantha Jones

The purpose of this study was to investigate the effects of the contextual learning method on science performance, attitudes toward science, and motivational factors that influence high school students to learn science. Gender differences in science performance and attitudes toward science were also investigated. The sample included four tenth-grade classes of African-American students enrolled in Chemistry I. All students were required to review for the Alabama High School Graduation Exam in Science. Students were administered a science pretest and posttest to measure science performance. A two-way analysis of covariance was performed on the test data. The results showed a main effect of contextual learning instruction on science achievement and no significant differences between females' and males' performance in science. The Science Attitude and the Alabama High School Graduation Exam (AHSGE) Review Class Surveys were administered to assess students' beliefs and attitudes toward science. The Science Attitude Survey results indicated a control effect in three subscales: perception of guardian's attitude, attitude toward success in science, and perception of teacher's attitude. No significant differences resulted between males and females in their beliefs about science from the attitude survey. However, students' attitudes toward science were more favorable in the contextual learning classes based on the results of the Review Class Survey. The survey data revealed that both males and females in the contextual classes had positive attitudes toward science and toward being active participants in the learning process. Qualitative data on student motivation were collected to examine the meaningfulness of the contextual learning content and materials. The majority of the students in the treatment (96%) and the control groups (86%) reported high interest in the lesson on Newton's three laws of motion. Both the treatment and the control groups indicated their interest ratings were a result of their prior experiences. This study shows that contextual learning instruction positively influences student motivation, interest, and achievement in science. Student achievement in science improved in the contextual learning classes as a result of increased interest due to learning that emphasized relevancy and purposeful meaning.

Nutritional and eating education improves knowledge and practice of patients with type 2 diabetes concerning dietary intake and blood glucose control in an outlying city of China.

PubMed

Wang, Huan; Song, Zhenfeng; Ba, Yanhui; Zhu, Lin; Wen, Ying

2014-10-01

To describe the knowledge, attitudes and practices of type 2 diabetics in Yakeshi City and to assess the effect of implementation of nutritional and eating education in enhancing knowledge and practices regarding a healthy diet. A questionnaire-based survey was conducted with 162 diabetics to determine their nutrition knowledge, attitudes and practices; fifty-four participants received nutritional and eating education for 6 months. Diabetes-related nutrition knowledge, awareness, practice accuracy, dietary intake and glycaemic control were assessed before and after education. Yakeshi, a remote city in northern China. A total of 162 type 2 diabetics recruited from three hospitals, fifty-four of whom were selected randomly to receive education. Among the 162 respondents, most diabetics (75%) considered that controlling diet was important in the methods of controlling blood glucose. Scores for knowledge, practices and overall KAP (knowledge-attitude-practice) were low, but scores for attitude were high. Participants with diabetes education experiences, practice duration over 1 year or high education level all had higher scores for KAP (P < 0·001, P < 0·05 and P < 0·001, respectively) than their counterparts. After education, patients' nutrition knowledge, awareness and practice accuracy improved significantly (P < 0·05). The rates of patients with recommended daily intake of vegetables, grains and dairy were boosted (P < 0·05). Various nutrient intakes increased (P < 0·05) but not protein, Fe, Zn and Se. Significant improvements were also found in glycaemic control (P < 0·05). Diabetics in Yakeshi had positive attitudes, but relatively poor nutrition knowledge and practices. Nutritional and eating education was effective in improving diabetics' nutrition knowledge and practices, and this optimal practice helped them control blood glucose effectively.

Causal modeling of secondary science students' intentions to enroll in physics

NASA Astrophysics Data System (ADS)

Crawley, Frank E.; Black, Carolyn B.

The purpose of this study was to explore the utility of the theory of planned behavior model developed by social psychologists for understanding and predicting the behavioral intentions of secondary science students regarding enrolling in physics. In particular, the study used a three-stage causal model to investigate the links from external variables to behavioral, normative, and control beliefs; from beliefs to attitudes, subjective norm, and perceived behavioral control; and from attitudes, subjective norm, and perceived behavioral control to behavioral intentions. The causal modeling method was employed to verify the underlying causes of secondary science students' interest in enrolling physics as predicted in the theory of planned behavior. Data were collected from secondary science students (N = 264) residing in a central Texas city who were enrolled in earth science (8th grade), biology (9th grade), physical science (10th grade), or chemistry (11th grade) courses. Cause-and-effect relationships were analyzed using path analysis to test the direct effects of model variables specified in the theory of planned behavior. Results of this study indicated that students' intention to enroll in a high school physics course was determined by their attitude toward enrollment and their degree of perceived behavioral control. Attitude, subjective norm, and perceived behavioral control were, in turn, formed as a result of specific beliefs that students held about enrolling in physics. Grade level and career goals were found to be instrumental in shaping students' attitude. Immediate family members were identified as major referents in the social support system for enrolling in physics. Course and extracurricular conflicts and the fear of failure were shown to be the primary beliefs obstructing students' perception of control over physics enrollment. Specific recommendations are offered to researchers and practitioners for strengthening secondary school students' intentions to study physics.

Youth Attitudes towards Tobacco Control Laws: The Influence of Smoking Status and Grade in School

ERIC Educational Resources Information Center

Williams, Terrinieka T.; Jason, Leonard A.; Pokorny, Steven B.

2008-01-01

This study examined adolescent attitudes towards tobacco control laws. An exploratory factor analysis, using surveys from over 9,000 students, identified the following three factors: (1) youth attitudes towards the efficacy of tobacco control laws, (2) youth attitudes towards tobacco possession laws and (3) youth attitudes towards tobacco sales…

A longitudinal study of factors explaining attitude change towards gambling among adolescents

PubMed Central

Pallesen, Ståle; Hanss, Daniel; Molde, Helge; Griffiths, Mark D.; Mentzoni, Rune Aune

2016-01-01

Background and aims No previous study has investigated changes in attitudes toward gambling from under legal gambling age to legal gambling age. The aim of the present study was therefore to investigate attitudinal changes during this transition and to identify predictors of corresponding attitude change. Methods In all 1239 adolescents from a national representative sample participated in two survey waves (Wave 1; 17.5 years; Wave 2; 18.5 years). Results From Wave 1 to Wave 2 the sample became more acceptant toward gambling. A regression analysis showed that when controlling for attitudes toward gambling at Wave 1 males developed more acceptant attitudes than females. Neuroticism was inversely related to development of acceptant attitudes toward gambling from Wave 1 to Wave 2, whereas approval of gambling by close others at Wave 1 was positively associated with development of more acceptant attitudes. Continuous or increased participation in gambling was related to development of more acceptant attitudes from Wave 1 to Wave 2. Conclusions Attitudes toward gambling became more acceptant when reaching legal gambling age. Male gender, approval of gambling by close others and gambling participation predicted development of positive attitudes toward gambling whereas neuroticism was inversely related to development of positive attitudes toward gambling over time. PMID:28092188

A longitudinal study of factors explaining attitude change towards gambling among adolescents.

PubMed

Pallesen, Ståle; Hanss, Daniel; Molde, Helge; Griffiths, Mark D; Mentzoni, Rune Aune

2016-03-01

Background and aims No previous study has investigated changes in attitudes toward gambling from under legal gambling age to legal gambling age. The aim of the present study was therefore to investigate attitudinal changes during this transition and to identify predictors of corresponding attitude change. Methods In all 1239 adolescents from a national representative sample participated in two survey waves (Wave 1; 17.5 years; Wave 2; 18.5 years). Results From Wave 1 to Wave 2 the sample became more acceptant toward gambling. A regression analysis showed that when controlling for attitudes toward gambling at Wave 1 males developed more acceptant attitudes than females. Neuroticism was inversely related to development of acceptant attitudes toward gambling from Wave 1 to Wave 2, whereas approval of gambling by close others at Wave 1 was positively associated with development of more acceptant attitudes. Continuous or increased participation in gambling was related to development of more acceptant attitudes from Wave 1 to Wave 2. Conclusions Attitudes toward gambling became more acceptant when reaching legal gambling age. Male gender, approval of gambling by close others and gambling participation predicted development of positive attitudes toward gambling whereas neuroticism was inversely related to development of positive attitudes toward gambling over time.

Infection control: Knowledge and compliance among Saudi undergraduate dental students

PubMed Central

Al-Maweri, Sadeq Ali; Tarakji, Bassel; Shugaa-Addin, Bassam; Al-Shamiri, Hashem M.; Alaizari, Nader Ahmed; AlMasri, Ousamah

2015-01-01

Objective: This study aimed to assess the level of knowledge, attitudes, and practices regarding infection control procedures among undergraduate dental students. Methods: This was a questionnaire-based cross-sectional survey. A self-administered questionnaire consisting of questions on students’ vaccination status as well as knowledge and attitudes regarding infection control was sent to 600 undergraduate dental students in the fourth, fifth, and sixth year of the Al-Farabi College for Dentistry and Nursing, Riyadh, Saudi Arabia. The collected data were analyzed using SPSS software. The significance level was set at P<0.05. Results: The response rate was 85% (512 out of 600). While the vast majority of students (90%) had been vaccinated against hepatitis, only 37.4% have been assessed for anti-HBs. A total of 98.8% and 90.8% reported always wearing gloves and masks, respectively, during dental procedures. The use of protective eyewear was reported by only 29.2%. A significantly higher proportion of sixth-year students showed a positive attitude toward the treatment of patients with infectious diseases than other students of lower academic years. Approximately one-third of students reported having one or more occupational injuries while treating their patients. Conclusion: Although the students had good knowledge and attitudes regarding infection control, the compliance and practice levels regarding the same were low. Such findings highlight the necessity of continued infection-control education of Saudi dental students. PMID:26199855

Real-Time GNSS-Based Attitude Determination in the Measurement Domain.

PubMed

Zhao, Lin; Li, Na; Li, Liang; Zhang, Yi; Cheng, Chun

2017-02-05

A multi-antenna-based GNSS receiver is capable of providing high-precision and drift-free attitude solution. Carrier phase measurements need be utilized to achieve high-precision attitude. The traditional attitude determination methods in the measurement domain and the position domain resolve the attitude and the ambiguity sequentially. The redundant measurements from multiple baselines have not been fully utilized to enhance the reliability of attitude determination. A multi-baseline-based attitude determination method in the measurement domain is proposed to estimate the attitude parameters and the ambiguity simultaneously. Meanwhile, the redundancy of attitude resolution has also been increased so that the reliability of ambiguity resolution and attitude determination can be enhanced. Moreover, in order to further improve the reliability of attitude determination, we propose a partial ambiguity resolution method based on the proposed attitude determination model. The static and kinematic experiments were conducted to verify the performance of the proposed method. When compared with the traditional attitude determination methods, the static experimental results show that the proposed method can improve the accuracy by at least 0.03° and enhance the continuity by 18%, at most. The kinematic result has shown that the proposed method can obtain an optimal balance between accuracy and reliability performance.

Statistical Control Paradigm for Aerospace Structures Under Impulsive Disturbances

DTIC Science & Technology

2006-08-03

attitude control system with an innovative and robust statistical controller design shows significant promise for use in attitude hold mode operation...indicate that the existing attitude control system with an innovative and robust statistical controller design shows significant promise for use in...and three thrusters are for use in controlling the attitude of the satellite. Then the angular momentum of the satellite with three thrusters and a

Attitude and vibration control of a satellite containing flexible solar arrays by using reaction wheels, and piezoelectric transducers as sensors and actuators

NASA Astrophysics Data System (ADS)

da Fonseca, Ijar M.; Rade, Domingos A.; Goes, Luiz C. S.; de Paula Sales, Thiago

2017-10-01

The primary purpose of this paper is to provide insight into control-structure interaction for satellites comprising flexible appendages and internal moving components. The physical model considered herein aiming to attend such purpose is a rigid-flexible satellite consisting of a rigid platform containing two rotating flexible solar panels. The solar panels rotation is assumed to be in a sun-synchronous configuration mode. The panels contain surface-bonded piezoelectric patches that can be used either as sensors for the elastic displacements or as actuators to counteract the vibration motion. It is assumed that in the normal mode operation the satellite platform points towards the Earth while the solar arrays rotate so as to follow the Sun. The vehicle moves in a low Earth polar orbit. The technique used to obtain the mathematical model combines the Lagrangian formulation with the Finite Elements Method used to describe the dynamics of the solar panel. The gravity-gradient torque as well as the torque due to the interaction of the Earth magnetic field and the satellite internal residual magnetic moment is included as environmental perturbations. The actuators are three reaction wheels for attitude control and piezoelectric actuators to control the flexible motion of the solar arrays. Computer simulations are performed using the MATLAB® software package. The following on-orbit satellite operating configurations are object of analysis: i) Satellite pointing towards the Earth (Earth acquisition maneuver) by considering the initial conditions in the elastic displacement equal to zero, aiming the assessment of the flexible modes excitation by the referred maneuver; ii) the satellite pointing towards the Earth with the assumption of an initial condition different from zero for the flexible motion such that the attitude alterations are checked against the elastic motion disturbance; and iii) attitude acquisition accomplished by taking into account initial conditions different from zero for both attitude and elastic vibrations. Additionally, the control efforts for the three cases are compared. Results indicate that the attitude control is able to excite the solar panels' vibration modes and vice-versa. The piezoelectric vibration control shows significant performance improvement when compared to contributions of the attitude control to the vibration damping.

FADS: A demonstrator for MilComSat AOCS

NASA Astrophysics Data System (ADS)

Huddleston, Martin; Cope, Paul

1995-03-01

This project covers the attitude and orbit control systems (AOCS) research program being carried out as part of the MOD applied research program for AD CIS(OR)1. The project program is to evaluate the candidate sensor technologies and control algorithms, such as Kalman filters, which may be applied to future UK military ComSats. The specific needs of military satellites for robust and threat-resistant control are not offered by current civil technologies which normally use vulnerable earth sensors or RF pointing which is vulnerable to deception. The program is also to investigate ways of reducing control system complexity and improvements in attitude control precision by enabling structural modes to be controlled. The project examines the most promising attitude control system technologies required to support such future communications payloads. User requirements indicate a need for improved threat resistance and for narrower spot beams, and the program supports this perceived need by the use of improved sensors and control algorithms. Improved pointing on civil ComSats is normally by means of ground RF measurements to form a closed loop control system with the spacecraft. For threat reasons this method is unsuitable for military ComSats, and on-board sensors are therefore used. The use of Silicon array star or earth sensors are the most promising, and the sensor program is to concentrate on these. Limited development and available civil sensors will be considered. Experimental work is based on demonstrating and evaluating real hardware in-the-loop on an existing air bearing experimental rig. This offers the closest simulation of real flight performance that can be obtained. The program will develop the Filtered Attitude Determination System (FADS)rig to be fully representative of a MilSatCom satellite, threat-resistant AOCS solution, employing Silicon array star and earth sensors. Both the BAe Mosaic Earth Sensor (MES) nad Marconi Versatile Star Sensor (VSS) technologies show considerable potential as attitude sensors. The VSS and MES capabilities will be evalutated on the FADS rig.

Remote Spacecraft Attitude Control by Coulomb Charging

NASA Astrophysics Data System (ADS)

Stevenson, Daan

The possibility of inter-spacecraft collisions is a serious concern at Geosynchronous altitudes, where many high-value assets operate in proximity to countless debris objects whose orbits experience no natural means of decay. The ability to rendezvous with these derelict satellites would enable active debris removal by servicing or repositioning missions, but docking procedures are generally inhibited by the large rotational momenta of uncontrolled satellites. Therefore, a contactless means of reducing the rotation rate of objects in the space environment is desired. This dissertation investigates the viability of Coulomb charging to achieve such remote spacecraft attitude control. If a servicing craft imposes absolute electric potentials on a nearby nonspherical debris object, it will impart electrostatic torques that can be used to gradually arrest the object's rotation. In order to simulate the relative motion of charged spacecraft with complex geometries, accurate but rapid knowledge of the Coulomb interactions is required. To this end, a new electrostatic force model called the Multi-Sphere Method (MSM) is developed. All aspects of the Coulomb de-spin concept are extensively analyzed and simulated using a system with simplified geometries and one dimensional rotation. First, appropriate control algorithms are developed to ensure that the nonlinear Coulomb torques arrest the rotation with guaranteed stability. Moreover, the complex interaction of the spacecraft with the plasma environment and charge control beams is modeled to determine what hardware requirements are necessary to achieve the desired electric potential levels. Lastly, the attitude dynamics and feedback control development is validated experimentally using a scaled down terrestrial testbed. High voltage power supplies control the potential on two nearby conductors, a stationary sphere and a freely rotating cylinder. The nonlinear feedback control algorithms developed above are implemented to achieve rotation rate and absolute attitude control. Collectively, these studies decisively validate the feasibility of Coulomb charging for remote spacecraft attitude control.

Correlates of Chilean Adolescents’ Negative Attitudes Toward Cigarettes: The Role of Gender, Peer, Parental, and Environmental Factors

PubMed Central

Bares, Cristina; Delva, Jorge

2012-01-01

Introduction: We examined the association of peer, parental, and environmental factors with negative attitudes toward cigarettes among youth from Santiago, Chile. Methods: A total of 860 youth from Santiago, Chile, completed questions regarding their lifetime use of cigarettes, intentions to smoke, attitudes toward cigarettes, and questions that assessed peer, parental, and environmental factors. Results: For both boys and girls, peer disapproval of smoking was associated with more negative attitudes toward cigarettes and peer smoking was associated with less negative attitudes toward cigarettes. Peer pressure was significantly associated with more negative attitudes toward cigarettes for girls only. Parental smoking was associated with less negative attitudes and parental control with more negative attitudes, but these associations were significant in the overall sample only. School prevention efforts and exposure to cigarette ads were not associated with cigarette attitudes. Difficulty in accessing cigarettes was positively associated with negative attitudes for boys and girls. Conclusion: Smoking prevention efforts focus on attitude change, but scant information is available about the experiences that influence Chilean youth’s attitudes toward cigarettes. Results from the current study suggest that prevention efforts could benefit from gender-specific strategies. Girls’ but not boys’ attitudes were influenced by peer pressure. Moreover, negative attitudes toward cigarettes were associated with lower current smoking in girls only. Parental smoking was an important influence on youth’s attitudes toward cigarettes. Efforts to reduce smoking among Chilean youth may benefit from concurrently reducing parental smoking. PMID:22157230

Spanish women's attitudes towards post-fertilization effects of birth control methods.

PubMed

Lopez-del Burgo, Cristina; Lopez-de Fez, Carmen Marina; Osorio, Alfonso; Guzmán, José Lopez; de Irala, Jokin

2010-07-01

Some methods of family planning, such as oral contraceptives, emergency pill or intrauterine device, may occasionally work after fertilization. These effects may be important to some women. We explored Spanish women's attitudes towards contraceptive choices that may have occasional post-fertilization mechanisms of action. Cross-sectional study in a Spanish representative sample of 848 potentially fertile women, aged 18-49. Data were collected using a 30-item questionnaire about family planning. Logistic regression was used to identify variables associated with women's attitudes towards post-fertilization effects. The majority of women were married, had completed high school and had at least one child. Forty-five percent of women would not consider using a method that may work after fertilization and 57% would not consider using one that may work after implantation. Forty-eight percent of the sample would stop using a method if they learned that it sometimes works after fertilization, increasing to 63% when referring to a method that sometimes works after implantation. Women who believe that human life begins at fertilization, those who believe it is important to distinguish between spontaneous and induced embryo losses and women who report having a religion were less likely to consider the use of a method with some post-fertilization effects. The possibility of post-fertilization effects may influence Spanish women's choice of a family planning method. Information about mechanisms of action of birth control methods should be disclosed to women so that they can make informed choices. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

CAI: Overcoming Attitude Barriers.

ERIC Educational Resources Information Center

Netusil, Anton J.; Kockler, Lois H.

During each of two school quarters, approximately 60 college students enrolled in a mathematics course were randomly assigned to an experimental group or a control group. The control group received instruction by the lecture method only; the experimental group received the same instruction, except that six computer-assisted instruction (CAI) units…

Learning-based adaptive prescribed performance control of postcapture space robot-target combination without inertia identifications

NASA Astrophysics Data System (ADS)

Wei, Caisheng; Luo, Jianjun; Dai, Honghua; Bian, Zilin; Yuan, Jianping

2018-05-01

In this paper, a novel learning-based adaptive attitude takeover control method is investigated for the postcapture space robot-target combination with guaranteed prescribed performance in the presence of unknown inertial properties and external disturbance. First, a new static prescribed performance controller is developed to guarantee that all the involved attitude tracking errors are uniformly ultimately bounded by quantitatively characterizing the transient and steady-state performance of the combination. Then, a learning-based supplementary adaptive strategy based on adaptive dynamic programming is introduced to improve the tracking performance of static controller in terms of robustness and adaptiveness only utilizing the input/output data of the combination. Compared with the existing works, the prominent advantage is that the unknown inertial properties are not required to identify in the development of learning-based adaptive control law, which dramatically decreases the complexity and difficulty of the relevant controller design. Moreover, the transient and steady-state performance is guaranteed a priori by designer-specialized performance functions without resorting to repeated regulations of the controller parameters. Finally, the three groups of illustrative examples are employed to verify the effectiveness of the proposed control method.

Control torque generation of a CMG-based small satellite with MTGAC system: a trade-off study

NASA Astrophysics Data System (ADS)

Salleh, M. B.; Suhadis, N. M.; Rajendran, P.; Mazlan, N. M.

2018-05-01

In this paper, the gimbal angle compensation method using magnetic control law has been adopted for a small satellite operating in low earth orbit under disturbance toques influence. Three light weight magnetic torquers have been used to generate the magnetic compensation torque to bring diverge gimbals at preferable angle. The magnetic control torque required to compensate the gimbal angle is based on the gimbal error rate which depends on the gimbal angle converging time. A simulation study has been performed without and with the MTGAC system to investigate the amount of generated control torque as a trade-off between the power consumption, attitude control performance and CMG dynamic performance. Numerical simulations show that the satellite with the MTGAC system generates more control torques which leads to the additional power requirement but in return results in a favorable attitude control performance and gimbal angle management.

Implicit and Explicit Attitudes Predict Smoking Cessation: Moderating Effects of Experienced Failure to Control Smoking and Plans to Quit

PubMed Central

Chassin, Laurie; Presson, Clark C.; Sherman, Steven J.; Seo, Dong-Chul; Macy, Jon

2010-01-01

The current study tested implicit and explicit attitudes as prospective predictors of smoking cessation in a Midwestern community sample of smokers. Results showed that the effects of attitudes significantly varied with levels of experienced failure to control smoking and plans to quit. Explicit attitudes significantly predicted later cessation among those with low (but not high or average) levels of experienced failure to control smoking. Conversely, however, implicit attitudes significantly predicted later cessation among those with high levels of experienced failure to control smoking, but only if they had a plan to quit. Because smoking cessation involves both controlled and automatic processes, interventions may need to consider attitude change interventions that focus on both implicit and explicit attitudes. PMID:21198227

Pupil Control Ideology as a Source of Stress: The Student Teacher's Dilemma.

ERIC Educational Resources Information Center

Jones, Dan R.

One type of adaptation made by each student teacher is the development of attitudes toward controlling pupils. The student teachers' attitudes toward pupil control may be at odds with those of other educators and this difference in attitude, particularly in the case of the cooperating teacher, can cause stress. Attitudes toward pupil control can…

Upper Atmosphere Research Satellite (UARS) onboard attitude determination using a Kalman filter

NASA Technical Reports Server (NTRS)

Garrick, Joseph

1993-01-01

The Upper Atmospheric Research Satellite (UARS) requires a highly accurate knowledge of its attitude to accomplish its mission. Propagation of the attitude state using gyro measurements is not sufficient to meet the accuracy requirements, and must be supplemented by a observer/compensation process to correct for dynamics and observation anomalies. The process of amending the attitude state utilizes a well known method, the discrete Kalman Filter. This study is a sensitivity analysis of the discrete Kalman Filter as implemented in the UARS Onboard Computer (OBC). The stability of the Kalman Filter used in the normal on-orbit control mode within the OBC, is investigated for the effects of corrupted observations and nonlinear errors. Also, a statistical analysis on the residuals of the Kalman Filter is performed. These analysis is based on simulations using the UARS Dynamics Simulator (UARSDSIM) and compared against attitude requirements as defined by General Electric (GE). An independent verification of expected accuracies is performed using the Attitude Determination Error Analysis System (ADEAS).

The association between implicit and explicit attitudes toward smoking and support for tobacco control measures.

PubMed

Macy, Jonathan T; Chassin, Laurie; Presson, Clark C

2013-01-01

This study examined the association between implicit and explicit attitudes toward smoking and support for tobacco control policies. Participants were from an ongoing longitudinal study of the natural history of smoking who also completed a web-based assessment of implicit attitudes toward smoking (N = 1,337). Multiple regression was used to test the association between covariates (sex, age, educational attainment, parent status, and smoking status), implicit attitude toward smoking, and explicit attitude toward smoking and support for tobacco control policies. The moderating effect of the covariates on the relation between attitudes and support for policies was also tested. Females, those with higher educational attainment, parents, and nonsmokers expressed more support for tobacco control policy measures. For nonsmokers, only explicit attitude was significantly associated with support for policies. For smokers, both explicit and implicit attitudes were significantly associated with support. The effect of explicit attitude was stronger for those with lower educational attainment. Both explicit and implicit smoking attitudes are important for building support for tobacco control policies, particularly among smokers. More research is needed on how to influence explicit and implicit attitudes to inform policy advocacy campaigns.

Integrated orbit and attitude hardware-in-the-loop simulations for autonomous satellite formation flying

NASA Astrophysics Data System (ADS)

Park, Han-Earl; Park, Sang-Young; Kim, Sung-Woo; Park, Chandeok

2013-12-01

Development and experiment of an integrated orbit and attitude hardware-in-the-loop (HIL) simulator for autonomous satellite formation flying are presented. The integrated simulator system consists of an orbit HIL simulator for orbit determination and control, and an attitude HIL simulator for attitude determination and control. The integrated simulator involves four processes (orbit determination, orbit control, attitude determination, and attitude control), which interact with each other in the same way as actual flight processes do. Orbit determination is conducted by a relative navigation algorithm using double-difference GPS measurements based on the extended Kalman filter (EKF). Orbit control is performed by a state-dependent Riccati equation (SDRE) technique that is utilized as a nonlinear controller for the formation control problem. Attitude is determined from an attitude heading reference system (AHRS) sensor, and a proportional-derivative (PD) feedback controller is used to control the attitude HIL simulator using three momentum wheel assemblies. Integrated orbit and attitude simulations are performed for a formation reconfiguration scenario. By performing the four processes adequately, the desired formation reconfiguration from a baseline of 500-1000 m was achieved with meter-level position error and millimeter-level relative position navigation. This HIL simulation demonstrates the performance of the integrated HIL simulator and the feasibility of the applied algorithms in a real-time environment. Furthermore, the integrated HIL simulator system developed in the current study can be used as a ground-based testing environment to reproduce possible actual satellite formation operations.

Real-Time GNSS-Based Attitude Determination in the Measurement Domain

PubMed Central

Zhao, Lin; Li, Na; Li, Liang; Zhang, Yi; Cheng, Chun

2017-01-01

A multi-antenna-based GNSS receiver is capable of providing high-precision and drift-free attitude solution. Carrier phase measurements need be utilized to achieve high-precision attitude. The traditional attitude determination methods in the measurement domain and the position domain resolve the attitude and the ambiguity sequentially. The redundant measurements from multiple baselines have not been fully utilized to enhance the reliability of attitude determination. A multi-baseline-based attitude determination method in the measurement domain is proposed to estimate the attitude parameters and the ambiguity simultaneously. Meanwhile, the redundancy of attitude resolution has also been increased so that the reliability of ambiguity resolution and attitude determination can be enhanced. Moreover, in order to further improve the reliability of attitude determination, we propose a partial ambiguity resolution method based on the proposed attitude determination model. The static and kinematic experiments were conducted to verify the performance of the proposed method. When compared with the traditional attitude determination methods, the static experimental results show that the proposed method can improve the accuracy by at least 0.03° and enhance the continuity by 18%, at most. The kinematic result has shown that the proposed method can obtain an optimal balance between accuracy and reliability performance. PMID:28165434

Integrating evidence-based teaching into to clinical practice should improve outcomes.

PubMed

Richards, Derek

2005-01-01

Sources used were Medline, Embase, the Education Resources Information Centre , Cochrane Controlled Trials Register, Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects, Health Technology Assessment database, Best Evidence, Best Evidence Medical Education and Science Citation Index, along with reference lists of known systematic reviews. Studies were chosen for inclusion if they evaluated the effects of postgraduate evidence-based medicine (EBM) or critical appraisal teaching in comparison with a control group or baseline before teaching, using a measure of participants' learning achievements or patients' health gains as outcomes. Articles were graded as either level 1 (randomised controlled trials (RCT)) or level 2 (non-randomised studies that either had a comparison with a control group), or a before and after comparison without a control group. Learning achievement was assessed separately for knowledge, critical appraisal skills, attitudes and behaviour. Because of obvious heterogeneity in the features of individual studies, their quality and assessment tools used, a meta-analysis could not be carried out. Conclusions were weighted by methodological quality. Twenty-three relevant studies were identified, comprising four RCT, seven non-RCT, and 12 before and after comparison studies. Eighteen studies (including two RCT) evaluated a standalone teaching method and five studies (including two RCT) evaluated a clinically integrated teaching method. Standalone teaching improved knowledge but not skills, attitudes or behaviour. Clinically integrated teaching improved knowledge, skills, attitudes and behaviour. Teaching of EBM should be moved from classrooms to clinical practice to achieve improvements in substantial outcomes.

Minority attitudes toward contraception.

PubMed

Mitchell, J O

1974-12-01

The training division of the Los Angeles Regional Family Planning Council conducted a seminar for minority members to discover attitudes toward birth control. Indian-Americans, Mexican-Americans, Asian-Americans, and Black-Americans participated. Some fears and misunderstandings relative to birth control were voiced. The timidity of recent Chinese immigrants was mentioned. Male reluctance to use birth control out of a sense of machismo was mentioned in relation to Black- and Mexican-Americans. The conclusion was that, when birth control methods are adequately explained, women of all ethnic groups are willing to use them. To allay fears, suspicions, and concerns, family planning should be presented to minority communities as a health service and not a social service. Family planning clinics would be more accepted in these communities if they expanded their work into other health areas.

A recurrent neural-network-based sensor and actuator fault detection and isolation for nonlinear systems with application to the satellite's attitude control subsystem.

PubMed

Talebi, H A; Khorasani, K; Tafazoli, S

2009-01-01

This paper presents a robust fault detection and isolation (FDI) scheme for a general class of nonlinear systems using a neural-network-based observer strategy. Both actuator and sensor faults are considered. The nonlinear system considered is subject to both state and sensor uncertainties and disturbances. Two recurrent neural networks are employed to identify general unknown actuator and sensor faults, respectively. The neural network weights are updated according to a modified backpropagation scheme. Unlike many previous methods developed in the literature, our proposed FDI scheme does not rely on availability of full state measurements. The stability of the overall FDI scheme in presence of unknown sensor and actuator faults as well as plant and sensor noise and uncertainties is shown by using the Lyapunov's direct method. The stability analysis developed requires no restrictive assumptions on the system and/or the FDI algorithm. Magnetorquer-type actuators and magnetometer-type sensors that are commonly employed in the attitude control subsystem (ACS) of low-Earth orbit (LEO) satellites for attitude determination and control are considered in our case studies. The effectiveness and capabilities of our proposed fault diagnosis strategy are demonstrated and validated through extensive simulation studies.

Angular-Rate Estimation Using Quaternion Measurements

NASA Technical Reports Server (NTRS)

Azor, Ruth; Bar-Itzhack, Y.; Deutschmann, Julie K.; Harman, Richard R.

1998-01-01

In most spacecraft (SC) there is a need to know the SC angular rate. Precise angular rate is required for attitude determination, and a coarse rate is needed for attitude control damping. Classically, angular rate information is obtained from gyro measurements. These days, there is a tendency to build smaller, lighter and cheaper SC, therefore the inclination now is to do away with gyros and use other means and methods to determine the angular rate. The latter is also needed even in gyro equipped satellites when performing high rate maneuvers whose angular-rate is out of range of the on board gyros or in case of gyro failure. There are several ways to obtain the angular rate in a gyro-less SC. When the attitude is known, one can differentiate the attitude in whatever parameters it is given and use the kinematics equation that connects the derivative of the attitude with the satellite angular-rate and compute the latter. Since SC usually utilize vector measurements for attitude determination, the differentiation of the attitude introduces a considerable noise component in the computed angular-rate vector.

Robust high-precision attitude control for flexible spacecraft with improved mixed H2/H∞ control strategy under poles assignment constraint

NASA Astrophysics Data System (ADS)

Liu, Chuang; Ye, Dong; Shi, Keke; Sun, Zhaowei

2017-07-01

A novel improved mixed H2/H∞ control technique combined with poles assignment theory is presented to achieve attitude stabilization and vibration suppression simultaneously for flexible spacecraft in this paper. The flexible spacecraft dynamics system is described and transformed into corresponding state space form. Based on linear matrix inequalities (LMIs) scheme and poles assignment theory, the improved mixed H2/H∞ controller does not restrict the equivalence of the two Lyapunov variables involved in H2 and H∞ performance, which can reduce conservatives compared with traditional mixed H2/H∞ controller. Moreover, it can eliminate the coupling of Lyapunov matrix variables and system matrices by introducing slack variable that provides additional degree of freedom. Several simulations are performed to demonstrate the effectiveness and feasibility of the proposed method in this paper.

Older Adults and Emerging Digital Service Delivery: A Mixed Methods Study on Information and Communications Technology Use, Skills, and Attitudes.

PubMed

Siren, Anu; Knudsen, Sine Grønborg

2017-01-01

Based on data from a survey (n = 3291) and 14 qualitative interviews among Danish older adults, this study investigated the use of, and attitudes toward, information communications technology (ICT) and the digital delivery of public services. While age, gender, and socioeconomic status were associated with use of ICT, these determinants lost their explanatory power when we controlled for attitudes and experiences. We identified three segments that differed in their use of ICT and attitudes toward digital service delivery. As nonuse of ICT often results from the lack of willingness to use it rather than from material or cognitive deficiencies, policy measures for bridging the digital divide should focus on skills and confidence rather than on access or ability.

Attitude Control Subsystem for the Advanced Communications Technology Satellite

NASA Technical Reports Server (NTRS)

Hewston, Alan W.; Mitchell, Kent A.; Sawicki, Jerzy T.

1996-01-01

This paper provides an overview of the on-orbit operation of the Attitude Control Subsystem (ACS) for the Advanced Communications Technology Satellite (ACTS). The three ACTS control axes are defined, including the means for sensing attitude and determining the pointing errors. The desired pointing requirements for various modes of control as well as the disturbance torques that oppose the control are identified. Finally, the hardware actuators and control loops utilized to reduce the attitude error are described.

Effects of group sexual counseling on the traditional perceptions and attitudes of Iranian pregnant women

PubMed Central

Navidian, Ali; Rigi, Shahindokht Navabi; Soltani, Parvin

2016-01-01

Background Marital relationships may fluctuate due to physical and psychological changes during pregnancy. This study aimed to investigate the effect of group sexual counseling on the traditional perceptions and attitudes of pregnant women. Methods This was a quasiexperimental intervention study. Among the pregnant women who were referred to health care centers in Zahedan, Iran, in 2015 for routine care during pregnancy, 100 individuals were chosen and randomly categorized into two groups: intervention (n=50) and control (n=50). Variables were the participant’s attitudes and beliefs on sexual activity during pregnancy. The data were collected during pregnancy using the Sexual Activities and Attitudes Questionnaire. The questionnaire was completed before and 6 weeks after five sessions of group sexual counseling. Data were analyzed using SPSS software (Version 20) with descriptive and analytical statistics. Results The mean of score changes for sexual attitudes and traditional perceptions in the intervention group was significantly higher than that in the control group (P<0.0001). Analysis of covariance also showed that the mean score of the participant’s traditional perceptions and sexual attitudes in both groups was significantly different after the group sexual counseling. Discussion Due to the positive effect of group sexual counseling on improving the attitudes of pregnant women about sexual issues and reframing the traditional perceptions over sexual activities during pregnancy, it is recommended that this educational intervention should be integrated into counseling and prenatal care for pregnant women. PMID:27366105

Implicit and explicit attitudes predict smoking cessation: moderating effects of experienced failure to control smoking and plans to quit.

PubMed

Chassin, Laurie; Presson, Clark C; Sherman, Steven J; Seo, Dong-Chul; Macy, Jonathan T

2010-12-01

The current study tested implicit and explicit attitudes as prospective predictors of smoking cessation in a Midwestern community sample of smokers. Results showed that the effects of attitudes significantly varied with levels of experienced failure to control smoking and plans to quit. Explicit attitudes significantly predicted later cessation among those with low (but not high or average) levels of experienced failure to control smoking. Conversely, however, implicit attitudes significantly predicted later cessation among those with high levels of experienced failure to control smoking, but only if they had a plan to quit. Because smoking cessation involves both controlled and automatic processes, interventions may need to consider attitude change interventions that focus on both implicit and explicit attitudes. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

Attitude control system conceptual design for the GOES-N spacecraft series

NASA Technical Reports Server (NTRS)

Markley, F. L.; Bauer, F. H.; Deily, J. J.; Femiano, M. D.

1991-01-01

The attitude determination sensing and processing of the system are considered, and inertial reference units, star trackers, and beacons and landmarks are discussed as well as an extended Kalman filter and expected attitude-determination performance. The baseline controller is overviewed, and a spacecraft motion compensation (SMC) algorithm, disturbance environment, and SMC performance expectations are covered. Detailed simulation results are presented, and emphasis is placed on dynamic models, attitude estimation and control, and SMC disturbance accommmodation. It is shown that the attitude control system employing gyro/star tracker sensing and active three-axis control with reaction wheels is capable of maintaining attitude errors of 1.7 microrad or less on all axes in the absence of attitude disturbances, and that the sensor line-of-sight pointing errors can be reduced to 0.1 microrad by SMC.

Design and Integration of an All-Magnetic Attitude Control System for FASTSAT-HSV01's Multiple Pointing Objectives

NASA Technical Reports Server (NTRS)

DeKock, Brandon; Sanders, Devon; Vanzwieten, Tannen; Capo-Lugo, Pedro

2011-01-01

The FASTSAT-HSV01 spacecraft is a microsatellite with magnetic torque rods as it sole attitude control actuator. FASTSAT s multiple payloads and mission functions require the Attitude Control System (ACS) to maintain Local Vertical Local Horizontal (LVLH)-referenced attitudes without spin-stabilization, while the pointing errors for some attitudes be significantly smaller than the previous best-demonstrated for this type of control system. The mission requires the ACS to hold multiple stable, unstable, and non-equilibrium attitudes, as well as eject a 3U CubeSat from an onboard P-POD and recover from the ensuing tumble. This paper describes the Attitude Control System, the reasons for design choices, how the ACS integrates with the rest of the spacecraft, and gives recommendations for potential future applications of the work.

Medical student, nursing student, and non-health care respondents' implicit attitudes toward doctors and patients: Development and a pilot study of a new implicit attitudes test (IAT)

PubMed Central

Mazouni, Abdelhamid

2017-01-01

Introduction Medical educators have been concerned that medical students may decline in empathy for patients during the course of their training, based on studies measuring clinical empathy using psychometrically strong self-report measures. Clinical empathy is a complex construct, incorporating attitudes toward patients but also other components, such as professional detachment. Triangulation of extant measures with instruments based on nonreactive methods could provide a better understanding of whether and how physician attitudes toward patients may be changing during training. We sought to develop and pilot-test such a nonreactive method. Methods We develop variations of an implicit association test (IAT) designed to measure attitudes toward physicians and patients based on speed of reaction to images of actors and positive and negative words. In the IATs, the same actors are photographed as doctors, clinic outpatients, hospitalized inpatients, and as a “general public” control. We examine preliminary evidence for their validity by collecting pilot data from internet participants (not involved in the health professions), medical students, and nursing students. Results Internet participants (n = 314) and nursing students (n = 31) had more negative associations (IAT scores) with doctors than did medical students (n = 89); nursing students and female internet participants had more positive associations with hospitalized patients than did medical students and male internet participants. Medical students’ associations with hospitalized patients varied by year of training. Discussion This IAT may provide insight into implicit attitudes among those who enter training for the health profession and changes in those attitudes that may be inculcated during that training. PMID:28813524

Vulnerable Women’s Self-Care Needs in Knowledge, Attitude and Practice Concerning Sexually Transmitted Diseases

PubMed Central

Alimohammadi, Nasrollah; Baghersad, Zahra; Boroumandfar, Zahra

2016-01-01

Background: Vulnerable women are prone to sexually transmitted diseases (STD) due to their special conditions and poor knowledge about these diseases in the society. Therefore, the present study aimed to determine the vulnerable women’s self-care needs in knowledge, attitude and practice concerning STD. Methods: This is a cross-sectional-descriptive study conducted in 2014. The data collection was carried out using a self-administered structured questionnaire. 120 vulnerable women referring to centers affiliated to health and well-being center in Isfahan participated in this study. They were selected through proportional rationing sampling and filled out a researcher developed questionnaire containing information on personal characteristics, self-care knowledge, attitude, and practice needs toward the STD. The data were analyzed using statistical methods including Spearman & Pearson correlation co-efficient, independent t-test and ANOVA. All analyses were carried out using SPSS, 20. Results: Based on the results, most of the subjects mentioned that their priorities of self-care needs in domains of knowledge, attitude and practice were “familiarization with the types and contamination ways of sexually transmitted diseases” (57.9%); “diagnosis of STD only makes us anxious” (24.8), and “the method of washing the genital area before and after intercourse” 41.3%), respectively. There was a significant association among marital status, education, history of addiction, and self-care needs in domains of knowledge, attitude and practice (P<0.05). Conclusion: Results showed that vulnerable women not only knew their need about STD, but also paid attention to their attitude and practice needs toward STD. Therefore, educational programs should be designed and administrated by the experts, based on vulnerable women’s self-care needs concerning their knowledge, attitude and practice to prevent and control STD in vulnerable individuals. PMID:27382588

Attitude control with realization of linear error dynamics

NASA Technical Reports Server (NTRS)

Paielli, Russell A.; Bach, Ralph E.

1993-01-01

An attitude control law is derived to realize linear unforced error dynamics with the attitude error defined in terms of rotation group algebra (rather than vector algebra). Euler parameters are used in the rotational dynamics model because they are globally nonsingular, but only the minimal three Euler parameters are used in the error dynamics model because they have no nonlinear mathematical constraints to prevent the realization of linear error dynamics. The control law is singular only when the attitude error angle is exactly pi rad about any eigenaxis, and a simple intuitive modification at the singularity allows the control law to be used globally. The forced error dynamics are nonlinear but stable. Numerical simulation tests show that the control law performs robustly for both initial attitude acquisition and attitude control.

A multiple functional connector for high-resolution optical satellites

NASA Astrophysics Data System (ADS)

She, Fengke; Zheng, Gangtie

2017-11-01

For earth observation satellites, perturbations from actuators, such as CMGs and momentum wheels, and thermal loadings from support structures often have significant impact on the image quality of an optical. Therefore, vibration isolators and thermal deformation releasing devices nowadays often become important parts of an image satellite. However, all these devices will weak the connection stiffness between the optical instrument and the satellite bus structure. This will cause concern of the attitude control system design for worrying about possible negative effect on the attitude control. Therefore, a connection design satisfying all three requirements is a challenge of advanced image satellites. Chinese scientists have proposed a large aperture high-resolution satellite for earth observation. To meet all these requirements and ensure image quality, specified multiple function connectors are designed to meet these challenging requirements, which are: isolating vibration, releasing thermal deformation and ensuring whole satellite dynamic properties [1]. In this paper, a parallel spring guide flexure is developed for both vibration isolation and thermal deformation releasing. The stiffness of the flexure is designed to meet the vibration isolation requirement. To attenuate vibration, and more importantly to satisfy the stability requirement of the attitude control system, metal damping, which has many merits for space applications, are applied in this connecter to provide a high damping ratio and nonlinear stiffness. The capability of the connecter for vibration isolation and attenuation is validated through numerical simulation and experiments. Connecter parameter optimization is also conducted to meet both requirements of thermal deformation releasing and attitude control. Analysis results show that the in-orbit attitude control requirement is satisfied while the thermal releasing performance is optimized. The design methods and analysis results are also provided in the present paper.

Flight Mechanics and Control Requirements for a Modular Solar Electric Tug Operating in Earth-Moon Space

NASA Astrophysics Data System (ADS)

Woodcock, Gordon; Wingo, Dennis

2006-01-01

A modular design for a solar-electric tug was analyzed to establish flight control requirements and methods. Thrusters are distributed around the periphery of the solar array. This design enables modules to be berthed together to create a larger system from smaller modules. It requires a different flight mode than traditional design and a different thrust direction scheme, to achieve net thrust in the desired direction, observe thruster pointing constraints that avoid plume impingement on the tug, and balance moments. The array is perpendicular to the Sun vector for maximum electric power. The tug may maintain a constant inertial attitude or rotate around the Sun vector once per orbit. Either non-rotating or constant angular velocity rotation offers advantages over the conventional flight mode, which has highly variable roll rates. The baseline single module has 12 thrusters: two 2-axis gimbaling main thrusters, one at each ``end'', and two back-to-back Z axis thrusters at each corner of the array. Thruster pointing and throttling were optimized to maximize net thrust effectiveness while observing constraints. Control design used a spread sheet with Excel Solver to calculate nominal thruster pointing and throttling. These results are used to create lookup tables. A conventional control system generates a thruster pointing and throttling overlay on the nominals to maintain active attitude control. Gravity gradients can cause major attitude perturbations during occultation periods if thrust is off during these periods. Thrust required to maintain attitude is about 4% of system rated power. This amount of power can be delivered by a battery system, avoiding the performance penalty if chemical propulsion thrusters were used to maintain attitude.

Finite-time control for nonlinear spacecraft attitude based on terminal sliding mode technique.

PubMed

Song, Zhankui; Li, Hongxing; Sun, Kaibiao

2014-01-01

In this paper, a fast terminal sliding mode control (FTSMC) scheme with double closed loops is proposed for the spacecraft attitude control. The FTSMC laws are included both in an inner control loop and an outer control loop. Firstly, a fast terminal sliding surface (FTSS) is constructed, which can drive the inner loop tracking-error and the outer loop tracking-error on the FTSS to converge to zero in finite time. Secondly, FTSMC strategy is designed by using Lyaponov's method for ensuring the occurrence of the sliding motion in finite time, which can hold the character of fast transient response and improve the tracking accuracy. It is proved that FTSMC can guarantee the convergence of tracking-error in both approaching and sliding mode surface. Finally, simulation results demonstrate the effectiveness of the proposed control scheme. © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Attitude maneuvers of a solar-powered electric orbital transfer vehicle

NASA Astrophysics Data System (ADS)

Jenkin, Alan B.

1992-08-01

Attitude maneuver requirements of a solar-powered electric orbital transfer vehicle have been studied in detail. This involved evaluation of the yaw, pitch, and roll profiles and associated angular accelerations needed to simultaneously steer the vehicle thrust vector and maintain the solar array pointed toward the sun. Maintaining the solar array pointed exactly at the sun leads to snap roll maneuvers which have very high (theoretically unbounded) accelerations, thereby imposing large torque requirements. The problem is exacerbated by the large solar arrays which are needed to generate the high levels of power needed by electric propulsion devices. A method of eliminating the snap roll maneuvers is presented. The method involves the determination of relaxed roll profiles which approximate a forced transition between alternate exact roll profiles and incur only small errors in solar array pointing. The method makes it feasible to perform the required maneuvers using currently available attitude control technology such as reaction wheels, hot gas jets, or gimballed main engines.

Bias Momentum Sizing for Hovering Dual-Spin Platforms

NASA Technical Reports Server (NTRS)

Lim, Kyong B.; Shin, Jong-Yeob; Moerder, Daniel D.

2006-01-01

An atmospheric flight vehicle in hover is typically controlled by varying its thrust vector. Achieving both levitation and attitude control with the propulsion system places considerable demands on it for agility and precision, particularly if the vehicle is statically unstable, or nearly so. These demands can be relaxed by introducing an appropriately sized angular momentum bias aligned with the vehicle's yaw axis, thus providing an additional margin of attitude stability about the roll and pitch axes. This paper describes a methodical approach for trading off angular momentum bias level needed with desired levels of vehicle response due to the design disturbance environment given a vehicle's physical parameters. It also describes several simplifications that provide a more physical and intuitive understanding of dual-spin dynamics for hovering atmospheric vehicles. This approach also mitigates the need for control torques and inadvertent actuator saturation difficulties in trying to stabilize a vehicle via control torques produced by unsteady aerodynamics, thrust vectoring, and unsteady throttling. Simulation results, based on a subscale laboratory test flying platform, demonstrate significant improvements in the attitude control robustness of the vehicle with respect to both wind disturbances and off-center of gravity payload changes during flight.

Social Mediation of Persuasive Media in Adolescent Substance Prevention

PubMed Central

Crano, William D.; Alvaro, Eusebio M.; Tan, Cara N.; Siegel, Jason T.

2017-01-01

Social commentary about prevention messages may affect their likelihood of acceptance. To investigate this possibility, student participants (N = 663) viewed three anti-marijuana advertisements, each followed immediately by videotaped discussions involving four adults or four adolescents using either extreme or moderate language in their positive commentaries. The commentaries were expected to affect participants’ perceptions of the extent to which the ads were designed to control their behavior (perceived control), which was hypothesized to inhibit persuasion. Two indirect effects analyses were conducted. Marijuana attitudes and usage intentions were the outcome variables. Both analyses revealed statistically significant source by language interactions on participants’ perceived control (both p < .02). Further analyses revealed significant indirect effects of language extremity on attitudes and intentions through perceived control with adult, but not peer sources (both p < .05). These perceptions were associated with more negative marijuana attitudes and diminished usage intentions when adults used moderate (vs. extreme) language in their favorable ad commentaries (both p < .05). The findings may facilitate development of more effective prevention methods that emphasize the importance the role of perceived control in persuasion, and the impact of interpersonal communication variations on acceptance of media-transmitted prevention messages. PMID:28301181

Social mediation of persuasive media in adolescent substance prevention.

PubMed

Crano, William D; Alvaro, Eusebio M; Tan, Cara N; Siegel, Jason T

2017-06-01

Social commentary about prevention messages may affect their likelihood of acceptance. To investigate this possibility, student participants (N = 663) viewed 3 antimarijuana advertisements, each followed immediately by videotaped discussions involving 4 adults or 4 adolescents using either extreme or moderate language in their positive commentaries. The commentaries were expected to affect participants' perceptions of the extent to which the ads were designed to control their behavior (perceived control), which was hypothesized to inhibit persuasion. Two indirect effects analyses were conducted. Marijuana attitudes and usage intentions were the outcome variables. Both analyses revealed statistically significant source by language interactions on participants' perceived control (both p < .02). Further analyses revealed significant indirect effects of language extremity on attitudes and intentions through perceived control with adult, but not peer sources (both p < .05). These perceptions were associated with more negative marijuana attitudes and diminished usage intentions when adults used moderate (vs. extreme) language in their favorable ad commentaries (both p < .05). The findings may facilitate development of more effective prevention methods that emphasize the importance of the role of perceived control in persuasion, and the impact of interpersonal communication variations on acceptance of media-transmitted prevention messages. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Vega roll and attitude control system algorithms trade-off study

NASA Astrophysics Data System (ADS)

Paulino, N.; Cuciniello, G.; Cruciani, I.; Corraro, F.; Spallotta, D.; Nebula, F.

2013-12-01

This paper describes the trade-off study for the selection of the most suitable algorithms for the Roll and Attitude Control System (RACS) within the FPS-A program, aimed at developing the new Flight Program Software of VEGA Launcher. Two algorithms were analyzed: Switching Lines (SL) and Quaternion Feedback Regulation. Using a development simulation tool that models two critical flight phases (Long Coasting Phase (LCP) and Payload Release (PLR) Phase), both algorithms were assessed with Monte Carlo batch simulations for both of the phases. The statistical outcomes of the results demonstrate a 100 percent success rate for Quaternion Feedback Regulation, and support the choice of this method.

Effect of Vaginal Hygiene Module to Attitudes and Behavior of Pathological Vaginal Discharge Prevention Among Female Adolescents in Slemanregency, Yogyakarta, Indonesia

PubMed Central

Sumarah, Sumarah; Widyasih, Hesty

2017-01-01

Objective: To determine the effect of vaginal hygiene module to attitudes and behavior of pathological vaginal discharge prevention in adolescent girls in Sleman Regency, Yogyakarta, Indonesia. Materials and methods: This present study is a quasi experiment with pretest and post-test control group design. A total of 80 female students was selected randomly from two secondary schools at the study site and then distributed equally to control and experimental group. Only participants in the experimental group were given self-learning vaginal hygiene module to maintain vaginal cleanliness. A questionnaire was used as an instrument to measure the attitudes and behavior of vaginal discharge prevention. Paired and independent sample t-tests with significance level (p value) at 0.05 and Confidence Interval (CI) of 95%were employed to compare the mean difference. Results: There is a significant difference in the students’ attitude and practice of pathological vaginal discharge prevention between intervention and control group. The students who have been exposed to vaginal hygiene module for six months showed better attitudes and practice in pathological vaginal discharge prevention compared to their counterpart in control group who do not receive any module. Conclusion: The present study implied that vaginal hygiene module can be provided widely for female adolescents at their early puberty. District health officers may work closely with schools’ health promoter to reach the students and create a supportive environment for reproductive health discussion and forum in order to achieve better adolescents’ reproductive health status. PMID:29282418

CubeSat Attitude Determination and Helmholtz Cage Design

DTIC Science & Technology

2012-03-01

4.2.2. 3.6 CubeSat Components The CubeSat used in this experiment is commanded and controlled via the Arduino Mega board that is based on the ATmel...UNIVERSITY AIR FORCE INSTITUTE OF TECHNOLOGY Wright-Patterson Air Force Base , Ohio APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED The views...ENY/12-M03 Abstract A method of 3-axis satellite attitude determination utilizing six body-fixed light sensors and a 3-axis magnetometer is analyzed. A

NASA/Howard University Large Space Structures Institute

NASA Technical Reports Server (NTRS)

Broome, T. H., Jr.

1984-01-01

Basic research on the engineering behavior of large space structures is presented. Methods of structural analysis, control, and optimization of large flexible systems are examined. Topics of investigation include the Load Correction Method (LCM) modeling technique, stabilization of flexible bodies by feedback control, mathematical refinement of analysis equations, optimization of the design of structural components, deployment dynamics, and the use of microprocessors in attitude and shape control of large space structures. Information on key personnel, budgeting, support plans and conferences is included.

High Accuracy Attitude Control of a Spacecraft Using Feedback Linearization

DTIC Science & Technology

1992-05-01

High Accuracy Attitude Control of a Spacecraft Using Feedback Linearization A Thesis Presented by Louis Joseph PoehIman, Captain, USAF B.S., U.S. Air...High Accuracy Attitude Control of a Spacecraft Using Feedback Linearization by Louis Joseph Poehlman, Captain, USAF Submitted to the Department of...31 2-4 Attitude Determination and Control System Architecture ................. 33 3-1 Exact Linearization Using Nonlinear Feedback

Maternal and Paternal Psychological Control as Moderators of the Link between Peer Attitudes and Adolescents' Risky Sexual Behavior

ERIC Educational Resources Information Center

Oudekerk, Barbara A.; Allen, Joseph P.; Hafen, Christopher A.; Hessel, Elenda T.; Szwedo, David E.; Spilker, Ann

2014-01-01

Maternal and paternal psychological control, peer attitudes, and the interaction of psychological control and peer attitudes at age 13 were examined as predictors of risky sexual behavior before age 16 in a community sample of 181 youth followed from age 13 to 16. Maternal psychological control moderated the link between peer attitudes and sexual…

Unscented predictive variable structure filter for satellite attitude estimation with model errors when using low precision sensors

NASA Astrophysics Data System (ADS)

Cao, Lu; Li, Hengnian

2016-10-01

For the satellite attitude estimation problem, the serious model errors always exist and hider the estimation performance of the Attitude Determination and Control System (ACDS), especially for a small satellite with low precision sensors. To deal with this problem, a new algorithm for the attitude estimation, referred to as the unscented predictive variable structure filter (UPVSF) is presented. This strategy is proposed based on the variable structure control concept and unscented transform (UT) sampling method. It can be implemented in real time with an ability to estimate the model errors on-line, in order to improve the state estimation precision. In addition, the model errors in this filter are not restricted only to the Gaussian noises; therefore, it has the advantages to deal with the various kinds of model errors or noises. It is anticipated that the UT sampling strategy can further enhance the robustness and accuracy of the novel UPVSF. Numerical simulations show that the proposed UPVSF is more effective and robustness in dealing with the model errors and low precision sensors compared with the traditional unscented Kalman filter (UKF).

Gender and the Effects of an Economic Empowerment Program on Attitudes Toward Sexual Risk-Taking Among AIDS-Orphaned Adolescent Youth in Uganda

PubMed Central

Ssewamala, Fred; Ismayilova, Leyla; McKay, Mary; Sperber, Elizabeth; Bannon, William; Alicea, Stacey

2009-01-01

Purpose This paper examines gender differences in attitudes towards sexual risk-taking behaviors of AIDS-orphaned youth participating in a randomized control trial testing an economic empowerment intervention in rural Uganda. Methods Adolescents (average age 13.7 years) who had lost one or both parents to AIDS from fifteen comparable schools were randomly assigned to either an experimental (n=135) or control condition (n=142). Adolescents in the experimental condition, in addition to usual care, also received support and incentives to save money toward secondary education. Results Findings indicate that although adolescent boys and girls within the experimental condition saved comparable amounts, the intervention appears to have benefited girls, in regards to the attitudes towards sexual risk-taking behavior, in a different way and to a lesser extent than boys. Conclusions Future research should investigate the possibility that adolescent girls might be able to develop equally large improvements in protective attitudes towards sexual risk-taking through additional components that address gendered social norms. PMID:20307827

System and method for correcting attitude estimation

NASA Technical Reports Server (NTRS)

Josselson, Robert H. (Inventor)

2010-01-01

A system includes an angular rate sensor disposed in a vehicle for providing angular rates of the vehicle, and an instrument disposed in the vehicle for providing line-of-sight control with respect to a line-of-sight reference. The instrument includes an integrator which is configured to integrate the angular rates of the vehicle to form non-compensated attitudes. Also included is a compensator coupled across the integrator, in a feed-forward loop, for receiving the angular rates of the vehicle and outputting compensated angular rates of the vehicle. A summer combines the non-compensated attitudes and the compensated angular rates of the to vehicle to form estimated vehicle attitudes for controlling the instrument with respect to the line-of-sight reference. The compensator is configured to provide error compensation to the instrument free-of any feedback loop that uses an error signal. The compensator may include a transfer function providing a fixed gain to the received angular rates of the vehicle. The compensator may, alternatively, include a is transfer function providing a variable gain as a function of frequency to operate on the received angular rates of the vehicle.

Asian International Students' Willingness to Seek Counseling: A Mixed-Methods Study

ERIC Educational Resources Information Center

Li, Peiwei; Wong, Y. Joel; Toth, Paul

2013-01-01

Using a mixed-methods survey design that was predominantly quantitative, this study explored Asian international students' willingness to seek counseling. Participants were 177 Asian international students recruited from a U.S. Midwestern University. After controlling for attitudes toward psychological help-seeking and past counseling experience,…

Improved method facilitates debulking and curing of phenolic impregnated asbestos

NASA Technical Reports Server (NTRS)

Gaines, P.

1966-01-01

Workpieces covered with phenolic impregnated asbestos tape and then wrapped with a specified thickness of nylon yarn under pressure, are debulked and cured in a standard oven. This method of debulking and curing is used in the fabrication of ablative chambers for the Gemini and Apollo attitude control engines.

Spacecraft drag-free technology development: On-board estimation and control synthesis

NASA Technical Reports Server (NTRS)

Key, R. W.; Mettler, E.; Milman, M. H.; Schaechter, D. B.

1982-01-01

Estimation and control methods for a Drag-Free spacecraft are discussed. The functional and analytical synthesis of on-board estimators and controllers for an integrated attitude and translation control system is represented. The framework for detail definition and design of the baseline drag-free system is created. The techniques for solution of self-gravity and electrostatic charging problems are applicable generally, as is the control system development.

Study on attitudes of students of Islamic Azad University Tehran Medical Branch toward food safety, 2016

PubMed Central

Miri, Ali; Poursadeghiyan, Mohsen; Baneshi, Mohammad Mehdi; Biglari, Hamed; Yari, Ahmad Reza; Khammar, Alireza

2017-01-01

Background Given the importance of high-quality healthy food for humans, contamination control is the most important concern for healthy staff. Aim To determine the attitudes of students at Islamic Azad University (Tehran Medical Branch) toward food safety. Methods This cross-sectional and analytic-descriptive study was conducted on 326 students of Azad University of Medical Sciences in 2016. A self-made questionnaire consisting of 40 questions was used. The reliability of the questionnaire was confirmed using internal consistency method (Cronbach’s alpha coefficient of 0.80). After collecting data, we use descriptive statistical indexes (mean and standard deviation) among demographic variables and the level of knowledge to describe and analyze the data. The participants’ attitudes and operation are measured by Spearman tests, and the analytical results are given using SPSS version 20. Results According to the findings, 55.3, 30 and 14.7 percent of students had high, moderate and low attitude scores toward food safety, respectively. In addition, male and female students had equal attitudes toward food safety, and no significant relationship between sex and attitude was observed a significant difference (p>0.05), but between educational levels (p=0.008) and ages (p=0.001) of students significance was a positive correlation. Conclusions Due to the low attitudes score of about half of the students of Islamic Azad University Tehran Medical Branch toward food safety, it can be claimed, food safety training in this community is required. PMID:28713497

Passive radiative cooling of a HTS coil for attitude orbit control in micro-spacecraft

NASA Astrophysics Data System (ADS)

Inamori, Takaya; Ozaki, Naoya; Saisutjarit, Phongsatorn; Ohsaki, Hiroyuki

2015-02-01

This paper proposes a novel radiative cooling system for a high temperature superconducting (HTS) coil for an attitude orbit control system in nano- and micro-spacecraft missions. These days, nano-spacecraft (1-10 kg) and micro-spacecraft (10-100 kg) provide space access to a broader range of spacecraft developers and attract interest as space development applications. In planetary and high earth orbits, most previous standard-size spacecraft used thrusters for their attitude and orbit control, which are not available for nano- and micro-spacecraft missions because of the strict power consumption, space, and weight constraints. This paper considers orbit and attitude control methods that use a superconducting coil, which interacts with on-orbit space plasmas and creates a propulsion force. Because these spacecraft cannot use an active cooling system for the superconducting coil because of their mass and power consumption constraints, this paper proposes the utilization of a passive radiative cooling system, in which the superconducting coil is thermally connected to the 3 K cosmic background radiation of deep space, insulated from the heat generation using magnetic holders, and shielded from the sun. With this proposed cooling system, the HTS coil is cooled to 60 K in interplanetary orbits. Because the system does not use refrigerators for its cooling system, the spacecraft can achieve an HTS coil with low power consumption, small mass, and low cost.

A cross-site intervention in Chinese rural migrants enhances HIV/AIDS knowledge, attitude and behavior.

PubMed

Li, Ning; Li, Xiaomei; Wang, Xueliang; Shao, Jin; Dou, Juanhua

2014-04-23

With the influx of rural migrants into urban areas, the spread of HIV has increased significantly in Shaanxi Province (China). Migrant workers are at high risk of HIV infection due to social conditions and hardships (isolation, separation, marginalization, barriers to services, etc.). We explored the efficacy of a HIV/AIDS prevention and control program for rural migrants in Shaanxi Province, administered at both rural and urban sites. Guidance concerning HIV/AIDS prevention was given to the experimental group (266 migrants) for 1 year by the center of disease control, community health agencies and family planning department. The intervention was conducted according to the HIV/AIDS Prevention Management Manual for Rural Migrants. A control group of migrants only received general population intervention. The impact of the intervention was evaluated by administering HIV/AIDS knowledge, attitudes and sexual behavior (KAB) questionnaires after 6 and 12 months. In the experimental group; 6 months of intervention achieved improvements in HIV/AIDS related knowledge. After 12 months; HIV/AIDS-related knowledge reached near maximal scores. Attitude and most behaviors scores were significantly improved. Moreover; the experimental group showed significant differences in HIV-AIDS knowledge; attitude and most behavior compared with the control group. The systematic long-term cross-site HIV/AIDS prevention in both rural and urban areas is a highly effective method to improve HIV/AIDS KAB among rural migrants.

Evidence that science locus of control orientation can be modified through instruction

NASA Astrophysics Data System (ADS)

Haury, David L.

A desire to foster enduring, positive attitudes toward science teaching among elementary school teachers led to study of self-perceptions. On the basis of evidence for strong links between locus of control orientation and attitudes, an attempt was made to enhance internality through instruction.A quasiexperimental research strategy was employed to compare the effects of two instructional treatments, with pretest measures being used to check the initial equivalence of treatment groups, and analysis of covariance (ANCOVA) being used to test treatment effects. Both treatments incorporated strategies known to have positive effects on attitudes, but the experimental treatment was novel in its emphasis on self-management, goal clarification, and individualized course expectations.There was found by ANCOVA to be a significant (p 0.05) difference in science locus of control (SciLOC) orientation between groups following treatment, with subjects exposed to the experimental treatment exhibiting greater internality. Quantitative comprehension and subject age were employed as covariates of SciLOC orientation, and subject gender was employed as a moderator variable. Though the treatment effect is small, accounting for 3% of the variance in SciLOC orientation, control orientation is shown susceptible to educational intervention. These results encourage attention to teacher attitudes from a rather new perspective, and they raise several interesting research questions regarding instructional methods and the long-term effects of enhancing internality.

An Evaluation of Attitude-Independent Magnetometer-Bias Determination Methods

NASA Technical Reports Server (NTRS)

Hashmall, J. A.; Deutschmann, Julie

1996-01-01

Although several algorithms now exist for determining three-axis magnetometer (TAM) biases without the use of attitude data, there are few studies on the effectiveness of these methods, especially in comparison with attitude dependent methods. This paper presents the results of a comparison of three attitude independent methods and an attitude dependent method for computing TAM biases. The comparisons are based on in-flight data from the Extreme Ultraviolet Explorer (EUVE), the Upper Atmosphere Research Satellite (UARS), and the Compton Gamma Ray Observatory (GRO). The effectiveness of an algorithm is measured by the accuracy of attitudes computed using biases determined with that algorithm. The attitude accuracies are determined by comparison with known, extremely accurate, star-tracker-based attitudes. In addition, the effect of knowledge of calibration parameters other than the biases on the effectiveness of all bias determination methods is examined.

Maternal and Paternal Psychological Control as Moderators of the Link between Peer Attitudes and Adolescents' Risky Sexual Behavior.

PubMed

Oudekerk, Barbara A; Allen, Joseph P; Hafen, Christopher A; Hessel, Elenda T; Szwedo, David E; Spilker, Ann

2014-05-01

Maternal and paternal psychological control, peer attitudes, and the interaction of psychological control and peer attitudes at age 13 were examined as predictors of risky sexual behavior before age 16 in a community sample of 181 youth followed from age 13 to 16. Maternal psychological control moderated the link between peer attitudes and sexual behavior. Peer acceptance of early sex predicted greater risky sexual behaviors, but only for teens whose mothers engaged in high levels of psychological control. Paternal psychological control demonstrated the same moderating effect for girls; for boys, however, high levels of paternal control predicted risky sex regardless of peer attitudes. Results are consistent with the theory that peer influences do not replace parental influences with regard to adolescent sexual behavior; rather, parental practices continue to serve an important role either directly forecasting sexual behavior or moderating the link between peer attitudes and sexual behavior.

Maternal and Paternal Psychological Control as Moderators of the Link between Peer Attitudes and Adolescents’ Risky Sexual Behavior

PubMed Central

Oudekerk, Barbara A.; Allen, Joseph P.; Hafen, Christopher A.; Hessel, Elenda T.; Szwedo, David E.; Spilker, Ann

2013-01-01

Maternal and paternal psychological control, peer attitudes, and the interaction of psychological control and peer attitudes at age 13 were examined as predictors of risky sexual behavior before age 16 in a community sample of 181 youth followed from age 13 to 16. Maternal psychological control moderated the link between peer attitudes and sexual behavior. Peer acceptance of early sex predicted greater risky sexual behaviors, but only for teens whose mothers engaged in high levels of psychological control. Paternal psychological control demonstrated the same moderating effect for girls; for boys, however, high levels of paternal control predicted risky sex regardless of peer attitudes. Results are consistent with the theory that peer influences do not replace parental influences with regard to adolescent sexual behavior; rather, parental practices continue to serve an important role either directly forecasting sexual behavior or moderating the link between peer attitudes and sexual behavior. PMID:25328265

Event-triggered attitude control of spacecraft

NASA Astrophysics Data System (ADS)

Wu, Baolin; Shen, Qiang; Cao, Xibin

2018-02-01

The problem of spacecraft attitude stabilization control system with limited communication and external disturbances is investigated based on an event-triggered control scheme. In the proposed scheme, information of attitude and control torque only need to be transmitted at some discrete triggered times when a defined measurement error exceeds a state-dependent threshold. The proposed control scheme not only guarantees that spacecraft attitude control errors converge toward a small invariant set containing the origin, but also ensures that there is no accumulation of triggering instants. The performance of the proposed control scheme is demonstrated through numerical simulation.

Distributed attitude synchronization of formation flying via consensus-based virtual structure

NASA Astrophysics Data System (ADS)

Cong, Bing-Long; Liu, Xiang-Dong; Chen, Zhen

2011-06-01

This paper presents a general framework for synchronized multiple spacecraft rotations via consensus-based virtual structure. In this framework, attitude control systems for formation spacecrafts and virtual structure are designed separately. Both parametric uncertainty and external disturbance are taken into account. A time-varying sliding mode control (TVSMC) algorithm is designed to improve the robustness of the actual attitude control system. As for the virtual attitude control system, a behavioral consensus algorithm is presented to accomplish the attitude maneuver of the entire formation and guarantee a consistent attitude among the local virtual structure counterparts during the attitude maneuver. A multiple virtual sub-structures (MVSSs) system is introduced to enhance current virtual structure scheme when large amounts of spacecrafts are involved in the formation. The attitude of spacecraft is represented by modified Rodrigues parameter (MRP) for its non-redundancy. Finally, a numerical simulation with three synchronization situations is employed to illustrate the effectiveness of the proposed strategy.

High-Precision Attitude Estimation Method of Star Sensors and Gyro Based on Complementary Filter and Unscented Kalman Filter

NASA Astrophysics Data System (ADS)

Guo, C.; Tong, X.; Liu, S.; Liu, S.; Lu, X.; Chen, P.; Jin, Y.; Xie, H.

2017-07-01

Determining the attitude of satellite at the time of imaging then establishing the mathematical relationship between image points and ground points is essential in high-resolution remote sensing image mapping. Star tracker is insensitive to the high frequency attitude variation due to the measure noise and satellite jitter, but the low frequency attitude motion can be determined with high accuracy. Gyro, as a short-term reference to the satellite's attitude, is sensitive to high frequency attitude change, but due to the existence of gyro drift and integral error, the attitude determination error increases with time. Based on the opposite noise frequency characteristics of two kinds of attitude sensors, this paper proposes an on-orbit attitude estimation method of star sensors and gyro based on Complementary Filter (CF) and Unscented Kalman Filter (UKF). In this study, the principle and implementation of the proposed method are described. First, gyro attitude quaternions are acquired based on the attitude kinematics equation. An attitude information fusion method is then introduced, which applies high-pass filtering and low-pass filtering to the gyro and star tracker, respectively. Second, the attitude fusion data based on CF are introduced as the observed values of UKF system in the process of measurement updating. The accuracy and effectiveness of the method are validated based on the simulated sensors attitude data. The obtained results indicate that the proposed method can suppress the gyro drift and measure noise of attitude sensors, improving the accuracy of the attitude determination significantly, comparing with the simulated on-orbit attitude and the attitude estimation results of the UKF defined by the same simulation parameters.

Energy management and attitude control for spacecraft

NASA Astrophysics Data System (ADS)

Costic, Bret Thomas

2001-07-01

This PhD dissertation describes the design and implementation of various control strategies centered around spacecraft applications: (i) an attitude control system for spacecraft, (ii) flywheels used for combined attitude and energy tracking, and (iii) an adaptive autobalancing control algorithm. The theory found in each of these sections is demonstrated through simulation or experimental results. An introduction to each of these three primary chapters can be found in chapter one. The main problem addressed in the second chapter is the quaternion-based, attitude tracking control of rigid spacecraft without angular velocity measurements and in the presence of an unknown inertia matrix. As a stepping-stone, an adaptive, full-state feedback controller that compensates for parametric uncertainty while ensuring asymptotic attitude tracking errors is designed. The adaptive, full-state feedback controller is then redesigned such that the need for angular velocity measurements is eliminated. The proposed adaptive, output feedback controller ensures asymptotic attitude tracking. This work uses a four-parameter representation of the spacecraft attitude that does not exhibit singular orientations as in the case of the previous three-parameter representation-based results. To the best of my knowledge, this represents the first solution to the adaptive, output feedback, attitude tracking control problem for the quaternion representation. Simulation results are included to illustrate the performance of the proposed output feedback control strategy. The third chapter is devoted to the use of multiple flywheels that integrate the energy storage and attitude control functions in space vehicles. This concept, which is referred to as an Integrated Energy Management and Attitude Control (IEMAC) system, reduces the space vehicle bus mass, volume, cost, and maintenance requirements while maintaining or improving the space vehicle performance. To this end, two nonlinear IEMAC strategies (model-based and adaptive) that simultaneously track a desired attitude trajectory and desired energy/power profile are presented. Both strategies ensure asymptotic tracking while the adaptive controller compensates for uncertain spacecraft inertia. In the final chapter, a control strategy is designed for a rotating, unbalanced disk. The control strategy, which is composed of a control torque and two control forces, regulates the disk displacement and ensures angular velocity tracking. The controller uses a desired compensation adaptation law and a gain adjusted forgetting factor to achieve exponential stability despite the lack of knowledge of the imbalance-related parameters, provided a mild persistency of excitation condition is satisfied.

Attributions and Attitudes of Mothers and Fathers in the United States.

PubMed

Lansford, Jennifer E; Bornstein, Marc H; Dodge, Kenneth A; Skinner, Ann T; Putnick, Diane L; Deater-Deckard, Kirby

2011-01-01

OBJECTIVE.: The present study examined mean level similarities and differences as well as correlations between U.S. mothers' and fathers' attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. DESIGN.: Interviews were conducted with both mothers and fathers in 139 European American, Latin American, and African American families. RESULTS.: Interactions between parent gender and ethnicity emerged for adult-controlled failure and perceived control over failure. Fathers reported higher adult-controlled failure and child-controlled failure attributions than did mothers, whereas mothers reported attitudes that were more progressive and modern than did fathers; these differences remained significant after controlling for parents' age, education, and possible social desirability bias. Ethnic differences emerged for five of the seven attributions and attitudes examined; four remained significant after controlling for parents' age, education, and possible social desirability bias. Medium effect sizes were found for concordance between parents in the same family for attributions regarding uncontrollable success, child-controlled failure, progressive attitudes, authoritarian attitudes, and modernity of attitudes after controlling for parents' age, education, and possible social desirability bias. CONCLUSIONS.: This work elucidates ways that parent gender and ethnicity relate to attributions regarding U.S. parents' successes and failures in caregiving situations and to their progressive versus authoritarian parenting attitudes.

Attributions and Attitudes of Mothers and Fathers in the United States

PubMed Central

Lansford, Jennifer E.; Bornstein, Marc H.; Dodge, Kenneth A.; Skinner, Ann T.; Putnick, Diane L.; Deater-Deckard, Kirby

2011-01-01

SYNOPSIS Objective. The present study examined mean level similarities and differences as well as correlations between U.S. mothers’ and fathers’ attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. Design. Interviews were conducted with both mothers and fathers in 139 European American, Latin American, and African American families. Results. Interactions between parent gender and ethnicity emerged for adult-controlled failure and perceived control over failure. Fathers reported higher adult-controlled failure and child-controlled failure attributions than did mothers, whereas mothers reported attitudes that were more progressive and modern than did fathers; these differences remained significant after controlling for parents’ age, education, and possible social desirability bias. Ethnic differences emerged for five of the seven attributions and attitudes examined; four remained significant after controlling for parents’ age, education, and possible social desirability bias. Medium effect sizes were found for concordance between parents in the same family for attributions regarding uncontrollable success, child-controlled failure, progressive attitudes, authoritarian attitudes, and modernity of attitudes after controlling for parents’ age, education, and possible social desirability bias. Conclusions. This work elucidates ways that parent gender and ethnicity relate to attributions regarding U.S. parents’ successes and failures in caregiving situations and to their progressive versus authoritarian parenting attitudes. PMID:21822402

SSS-A attitude control prelaunch analysis and operations plan

NASA Technical Reports Server (NTRS)

Werking, R. D.; Beck, J.; Gardner, D.; Moyer, P.; Plett, M.

1971-01-01

A description of the attitude control support being supplied by the Mission and Data Operations Directorate is presented. Descriptions of the computer programs being used to support the mission for attitude determination, prediction, control, and definitive attitude processing are included. In addition, descriptions of the operating procedures which will be used to accomplish mission objectives are provided.

Constrained dynamics approach for motion synchronization and consensus

NASA Astrophysics Data System (ADS)

Bhatia, Divya

In this research we propose to develop constrained dynamical systems based stable attitude synchronization, consensus and tracking (SCT) control laws for the formation of rigid bodies. The generalized constrained dynamics Equations of Motion (EOM) are developed utilizing constraint potential energy functions that enforce communication constraints. Euler-Lagrange equations are employed to develop the non-linear constrained dynamics of multiple vehicle systems. The constraint potential energy is synthesized based on a graph theoretic formulation of the vehicle-vehicle communication. Constraint stabilization is achieved via Baumgarte's method. The performance of these constrained dynamics based formations is evaluated for bounded control authority. The above method has been applied to various cases and the results have been obtained using MATLAB simulations showing stability, synchronization, consensus and tracking of formations. The first case corresponds to an N-pendulum formation without external disturbances, in which the springs and the dampers connected between the pendulums act as the communication constraints. The damper helps in stabilizing the system by damping the motion whereas the spring acts as a communication link relaying relative position information between two connected pendulums. Lyapunov stabilization (energy based stabilization) technique is employed to depict the attitude stabilization and boundedness. Various scenarios involving different values of springs and dampers are simulated and studied. Motivated by the first case study, we study the formation of N 2-link robotic manipulators. The governing EOM for this system is derived using Euler-Lagrange equations. A generalized set of communication constraints are developed for this system using graph theory. The constraints are stabilized using Baumgarte's techniques. The attitude SCT is established for this system and the results are shown for the special case of three 2-link robotic manipulators. These methods are then applied to the formation of N-spacecraft. Modified Rodrigues Parameters (MRP) are used for attitude representation of the spacecraft because of their advantage of being a minimum parameter representation. Constrained non-linear equations of motion for this system are developed and stabilized using a Proportional-Derivative (PD) controller derived based on Baumgarte's method. A system of 3 spacecraft is simulated and the results for SCT are shown and analyzed. Another problem studied in this research is that of maintaining SCT under unknown external disturbances. We use an adaptive control algorithm to derive control laws for the actuator torques and develop an estimation law for the unknown disturbance parameters to achieve SCT. The estimate of the disturbance is added as a feed forward term in the actual control law to obtain the stabilization of a 3-spacecraft formation. The disturbance estimates are generated via a Lyapunov analysis of the closed loop system. In summary, the constrained dynamics method shows a lot of potential in formation control, achieving stabilization, synchronization, consensus and tracking of a set of dynamical systems.

Are Informing Knowledge and Supportive Attitude Enough for Tobacco Control? A Latent Class Analysis of Cigarette Smoking Patterns among Medical Teachers in China

PubMed Central

Niu, Lu; Luo, Dan; Silenzio, Vincent M.B.; Xiao, Shuiyuan; Tian, Yongquan

2015-01-01

Background: This study is one part of a five-year tobacco-control project in China, which aimed to gain insight into the smoking behavior, knowledge, and attitudes among medical teachers in China. Methods: In May 2010, a cross-sectional survey was conducted among medical teachers of Xiangya Medical School, Central South University, China. Results: A total number of 682 medical teachers completed the surveys. Latent class analysis indicated the sample of smoking patterns was best represented by three latent subgroups of smoking consumption severity levels. Most respondents were informed of smoking related knowledge, but lack of knowledge on smoking cessation. Most of them held a supportive attitude towards their responsibilities among tobacco control, as well as the social significance of smoking. However, both smoking related knowledge and attitude were not correlated with severity of smoking consumption among medical teachers. Conclusion: The smoking prevalence among medical teachers in China remains high. Programs on smoking cessation training are required. Future study should also develop targeted interventions for subgroups of smokers based on smoking consumption. Persistent and effective anti-tobacco efforts are needed to achieve the goals of creating smoke-free campuses and hospitals. PMID:26404331

The forgotten smoker: a qualitative study of attitudes towards smoking, quitting, and tobacco control policies among continuing smokers

PubMed Central

2013-01-01

Background Although research suggests that the majority of smokers want to quit smoking, the uptake of Stop Smoking Services, designed to assist smokers with quitting, remains low. Little is known about continuing smokers who do not access these services, and opportunities to influence their motivation and encourage quit attempts through the uptake of services. Using PRIME theory, this study explored differences between continuing smokers who had varying levels of motivation to quit, in terms of their plans to quit, evaluative beliefs about smoking, cigarette dependence, and attitudes towards tobacco control policies and services. Methods Twenty-two current smokers, recruited from the community, were classified by motivation level to quit using a self-report questionnaire (two groups: high/low). Four focus groups (n=13) and individual interviews (n=9) were conducted with both groups using an interview guide incorporating aspects of PRIME theory. Discussion areas included motives for smoking, attitudes towards smoking and quitting, perceptions of dependence, motives for quitting, barriers to quitting, and attitudes towards existing and impending tobacco control policies and services. Verbatim transcripts were analysed using thematic framework analysis. Results All participants expressed low motivation to quit during discussions, despite some initially self-classifying as having high explicit levels of motivation to quit. Both groups reported similar attitudes towards smoking and quitting, including a perceived psychological addiction to smoking, positive evaluations about smoking which inhibited plans to quit, and similar suggested methods to increase motivation (simply wanting to, save money, improve health). Most felt that they ‘ought’ to quit as opposed to ‘wanted’ to. Little influence was ascribed towards tobacco control policies such as plain packaging and hidden sales displays, and participants felt that price increases of tobacco products needed to be considerable in order to influence motivation. Highly motivated smokers expressed more willingness to visit Stop Smoking Services, although none had done so. Conclusion Continuing smokers’ attitudes towards smoking and quitting suggests that research and policy need to focus on increasing smokers’ implicit motivation to quit smoking, even for those who classified themselves as having high motivation to quit. Targeted information and further education about Stop Smoking Services is required to increase uptake. PMID:23641875

Aircraft automatic-flight-control system with inversion of the model in the feed-forward path using a Newton-Raphson technique for the inversion

NASA Technical Reports Server (NTRS)

Smith, G. A.; Meyer, G.; Nordstrom, M.

1986-01-01

A new automatic flight control system concept suitable for aircraft with highly nonlinear aerodynamic and propulsion characteristics and which must operate over a wide flight envelope was investigated. This exact model follower inverts a complete nonlinear model of the aircraft as part of the feed-forward path. The inversion is accomplished by a Newton-Raphson trim of the model at each digital computer cycle time of 0.05 seconds. The combination of the inverse model and the actual aircraft in the feed-forward path alloys the translational and rotational regulators in the feedback path to be easily designed by linear methods. An explanation of the model inversion procedure is presented. An extensive set of simulation data for essentially the full flight envelope for a vertical attitude takeoff and landing aircraft (VATOL) is presented. These data demonstrate the successful, smooth, and precise control that can be achieved with this concept. The trajectory includes conventional flight from 200 to 900 ft/sec with path accelerations and decelerations, altitude changes of over 6000 ft and 2g and 3g turns. Vertical attitude maneuvering as a tail sitter along all axes is demonstrated. A transition trajectory from 200 ft/sec in conventional flight to stationary hover in the vertical attitude includes satisfactory operation through lift-cure slope reversal as attitude goes from horizontal to vertical at constant altitude. A vertical attitude takeoff from stationary hover to conventional flight is also demonstrated.

Some optimal considerations in attitude control systems. [evaluation of value of relative weighting between time and fuel for relay control law

NASA Technical Reports Server (NTRS)

Boland, J. S., III

1973-01-01

The conventional six-engine reaction control jet relay attitude control law with deadband is shown to be a good linear approximation to a weighted time-fuel optimal control law. Techniques for evaluating the value of the relative weighting between time and fuel for a particular relay control law is studied along with techniques to interrelate other parameters for the two control laws. Vehicle attitude control laws employing control moment gyros are then investigated. Steering laws obtained from the expression for the reaction torque of the gyro configuration are compared to a total optimal attitude control law that is derived from optimal linear regulator theory. This total optimal attitude control law has computational disadvantages in the solving of the matrix Riccati equation. Several computational algorithms for solving the matrix Riccati equation are investigated with respect to accuracy, computational storage requirements, and computational speed.

Continuous control of chaos based on the stability criterion.

PubMed

Yu, Hong Jie; Liu, Yan Zhu; Peng, Jian Hua

2004-06-01

A method of chaos control based on stability criterion is proposed in the present paper. This method can stabilize chaotic systems onto a desired periodic orbit by a small time-continuous perturbation nonlinear feedback. This method does not require linearization of the system around the stabilized orbit and only an approximate location of the desired periodic orbit is required which can be automatically detected in the control process. The control can be started at any moment by choosing appropriate perturbation restriction condition. It seems that more flexibility and convenience are the main advantages of this method. The discussions on control of attitude motion of a spacecraft, Rössler system, and two coupled Duffing oscillators are given as numerical examples.

Robustness and Actuator Bandwidth of MRP-Based Sliding Mode Control for Spacecraft Attitude Control Problems

NASA Astrophysics Data System (ADS)

Keum, Jung-Hoon; Ra, Sung-Woong

2009-12-01

Nonlinear sliding surface design in variable structure systems for spacecraft attitude control problems is studied. A robustness analysis is performed for regular form of system, and calculation of actuator bandwidth is presented by reviewing sliding surface dynamics. To achieve non-singular attitude description and minimal parameterization, spacecraft attitude control problems are considered based on modified Rodrigues parameters (MRP). It is shown that the derived controller ensures the sliding motion in pre-determined region irrespective of unmodeled effects and disturbances.

Changing attitudes to infection management in primary care: a controlled trial of active versus passive guideline implementation strategies.

PubMed

Onion, C W; Bartzokas, C A

1998-04-01

When attempting to implement evidence-based medicine, such as through clinical guidelines, we often rely on passive educational tactics, for example didactic lectures and bulletins. These methods involve the recipient in relatively superficial processing of information, and any consequent attitude changes can be expected to be short-lived. However, active methods, such as practice-based discussion, should involve recipients in deep processing, with more enduring attitude changes. In this experiment, the aim was to assess the efficacy of an active strategy at promoting deep processing and its effectiveness, relative to a typical passive method, at changing attitudes between groups of GPs over 12 months across an English Health District. All 191 GPs operating from 69 practices in the Wirral Health District of Northwest England were assigned, with minimization of known confounding variables, to three experimental groups: active, passive and control. The groups were shown to have similar learning styles. The objective of the study was to impart knowledge of best management of infections as captured in a series of locally developed clinical guidelines. The passive group GPs were given a copy of the guidelines and were invited to an hour-long lecture event. The GPs in the deep group were given a copy of the guidelines and were invited to engage in an hour-long discussion about the guideline content at their own premises. The control group received neither the guidelines nor any educational contact regarding them. Three months before and 12 months after the interventions, all GPs were sent a postal questionnaire on their preferred empirical antibiotic for 10 common bacterial infections. The responses were compared in order to ascertain whether increased knowledge of best clinical practice was evident in each group. Seventy-five per cent (144/191) of GPs responded to the pre-intervention questionnaire, 62 % (119/191) post-intervention. Thirty-four per cent (22/64) of GPs in the passive group attended the lecture; 91% (60/66) of the active group engaged in discussion at meetings with the authors. A significantly higher proportion of the active group participants' speaking time, during a sample of four visits, was devoted to verbal indicators of active processing than the passive group lecture attenders (difference = 55%, Fisher's exact test P = 0.002, OR = 11.5, 95% CI 2.1-113.4). Inter-observer agreement on the classification of the verbal evidence was highly statistically significant for all classes (Pearson's product moment correlation, P < 0.0005, r = +0.893 to +0.999) except repetition (P > 0.05, r = +0.407). Median compliance of responses with the guidelines improved by 2.5% within the control group and 4% within the passive, but by 23% within the active. The difference between the changes in the active and control groups was highly statistically significant at 17.5% (Mann-Whitney test, P = 0.004, 95% CI 6-29%). However, for the 10 infections, the median difference between the changes in the passive and control groups was not significant at 3% (P = 0.75, 95% CI -8 to +12. The median difference between changes in the active and passive groups was significant at 17% (P = 0.015, 95% CI 7-24%) in favour of the active. An active educational strategy attracted more participation and was more effective at generating deep cognitive processing than a passive strategy. A large improvement, lasting for at least 12 months, in attitude-compliance with guidelines on the optimal treatment of infections was imparted by the active processing method. A typical passive method was much less popular and had an insignificant impact on attitudes. The findings suggest that initiatives aiming to implement evidence-based guidelines must employ active educational strategies if enduring changes in attitude are to result.

A simple attitude control of quadrotor helicopter based on Ziegler-Nichols rules for tuning PD parameters.

PubMed

He, ZeFang; Zhao, Long

2014-01-01

An attitude control strategy based on Ziegler-Nichols rules for tuning PD (proportional-derivative) parameters of quadrotor helicopters is presented to solve the problem that quadrotor tends to be instable. This problem is caused by the narrow definition domain of attitude angles of quadrotor helicopters. The proposed controller is nonlinear and consists of a linear part and a nonlinear part. The linear part is a PD controller with PD parameters tuned by Ziegler-Nichols rules and acts on the quadrotor decoupled linear system after feedback linearization; the nonlinear part is a feedback linearization item which converts a nonlinear system into a linear system. It can be seen from the simulation results that the attitude controller proposed in this paper is highly robust, and its control effect is better than the other two nonlinear controllers. The nonlinear parts of the other two nonlinear controllers are the same as the attitude controller proposed in this paper. The linear part involves a PID (proportional-integral-derivative) controller with the PID controller parameters tuned by Ziegler-Nichols rules and a PD controller with the PD controller parameters tuned by GA (genetic algorithms). Moreover, this attitude controller is simple and easy to implement.

Sexuality Education Beliefs among Sexually Experienced Youth: Differences by Gender and Birth Control Use

ERIC Educational Resources Information Center

Tolma, Eleni L.; Vesely, Sara K.; Oman, Roy F.; Aspy, Cheryl B.; Rodine, Sharon

2006-01-01

Purpose: To examine whether gender and birth control use are associated with premarital sexual attitudes, beliefs about peers, family communication about sexual relationships, and sexuality education among sexually experienced youth. Methods: Data were collected from a randomly selected ethnically diverse youth sample (N = 1,253). Only the…

Just-in-Time Teaching Techniques through Web Technologies for Vocational Students' Reading and Writing Abilities

ERIC Educational Resources Information Center

Chantoem, Rewadee; Rattanavich, Saowalak

2016-01-01

This research compares the English language achievements of vocational students, their reading and writing abilities, and their attitudes towards learning English taught with just-in-time teaching techniques through web technologies and conventional methods. The experimental and control groups were formed, a randomized true control group…

Initial flight results of the TRMM Kalman filter

NASA Technical Reports Server (NTRS)

Andrews, Stephen F.; Morgenstern, Wendy M.

1998-01-01

The Tropical Rainfall Measuring Mission (TRMM) spacecraft is a nadir pointing spacecraft that nominally controls attitude based on the Earth Sensor Assembly (ESA) output. After a potential single point failure in the ESA was identified, the contingency attitude determination method chosen to backup the ESA-based system was a sixth-order extended Kalman filter that uses magnetometer and digital sun sensor measurements. A brief description of the TRMM Kalman filter will be given, including some implementation issues and algorithm heritage. Operational aspects of the Kalman filter and some failure detection and correction will be described. The Kalman filter was tested in a sun pointing attitude and in a nadir pointing attitude during the in-orbit checkout period, and results from those tests will be presented. This paper will describe some lessons learned from the experience of the TRMM team.

Initial Flight Results of the TRMM Kalman Filter

NASA Technical Reports Server (NTRS)

Andrews, Stephen F.; Morgenstern, Wendy M.

1998-01-01

The Tropical Rainfall Measuring Mission (TRMM) spacecraft is a nadir pointing spacecraft that nominally controls attitude based on the Earth Sensor Assembly (ESA) output. After a potential single point failure in the ESA was identified, the contingency attitude determination method chosen to backup the ESA-based system was a sixth-order extended Kalman filter that uses magnetometer and digital sun sensor measurements. A brief description of the TRMM Kalman filter will be given, including some implementation issues and algorithm heritage. Operational aspects of the Kalman filter and some failure detection and correction will be described. The Kalman filter was tested in a sun pointing attitude and in a nadir pointing attitude during the in-orbit checkout period, and results from those tests will be presented. This paper will describe some lessons learned from the experience of the TRMM team.

6 DOF synchronized control for spacecraft formation flying with input constraint and parameter uncertainties.

PubMed

Lv, Yueyong; Hu, Qinglei; Ma, Guangfu; Zhou, Jiakang

2011-10-01

This paper treats the problem of synchronized control of spacecraft formation flying (SFF) in the presence of input constraint and parameter uncertainties. More specifically, backstepping based robust control is first developed for the total 6 DOF dynamic model of SFF with parameter uncertainties, in which the model consists of relative translation and attitude rotation. Then this controller is redesigned to deal with the input constraint problem by incorporating a command filter such that the generated control could be implementable even under physical or operating constraints on the control input. The convergence of the proposed control algorithms is proved by the Lyapunov stability theorem. Compared with conventional methods, illustrative simulations of spacecraft formation flying are conducted to verify the effectiveness of the proposed approach to achieve the spacecraft track the desired attitude and position trajectories in a synchronized fashion even in the presence of uncertainties, external disturbances and control saturation constraint. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

Optimal Electrical Energy Slewing for Reaction Wheel Spacecraft

NASA Astrophysics Data System (ADS)

Marsh, Harleigh Christian

The results contained in this dissertation contribute to a deeper level of understanding to the energy required to slew a spacecraft using reaction wheels. This work addresses the fundamental manner in which spacecrafts are slewed (eigenaxis maneuvering), and demonstrates that this conventional maneuver can be dramatically improved upon in regards to reduction of energy, dissipative losses, as well as peak power. Energy is a fundamental resource that effects every asset, system, and subsystem upon a spacecraft, from the attitude control system which orients the spacecraft, to the communication subsystem to link with ground stations, to the payloads which collect scientific data. For a reaction wheel spacecraft, the attitude control system is a particularly heavy load on the power and energy resources on a spacecraft. The central focus of this dissertation is reducing the burden which the attitude control system places upon the spacecraft in regards to electrical energy, which is shown in this dissertation to be a challenging problem to computationally solve and analyze. Reducing power and energy demands can have a multitude of benefits, spanning from the initial design phase, to in-flight operations, to potentially extending the mission life of the spacecraft. This goal is approached from a practical standpoint apropos to an industry-flight setting. Metrics to measure electrical energy and power are developed which are in-line with the cost associated to operating reaction wheel based attitude control systems. These metrics are incorporated into multiple families of practical high-dimensional constrained nonlinear optimal control problems to reduce the electrical energy, as well as the instantaneous power burdens imposed by the attitude control system upon the spacecraft. Minimizing electrical energy is shown to be a problem in L1 optimal control which is nonsmooth in regards to state variables as well as the control. To overcome the challenge of nonsmoothness, a method is adopted in this dissertation to transform the nonsmooth minimum electrical energy problem into an equivalent smooth formulation, which then allows standard techniques in optimal control to solve and analyze the problem. Through numerically solving families of optimal control problems, the relationship between electrical energy and transfer time is identified and explored for both off-and on-eigenaxis maneuvering, under minimum dissipative losses as well as under minimum electrical energy. A trade space between on-and off-eigenaxis maneuvering is identified, from which is shown that agile near time optimal maneuvers exist within the energy budget associated with conventional eigenaxis maneuvering. Moreover, even for conventional eigenaxis maneuvering, energy requirements can be dramatically reduced by maneuvering off-eigenaxis. These results address one of the fundamental assumptions in the field of optimal path design verses conventional maneuver design. Two practical flight situations are addressed in this dissertation in regards to reducing energy and power: The case when the attitude of the spacecraft is predetermined, and the case where reaction wheels can not be directly controlled. For the setting where the attitude of spacecraft is on a predefined trajectory, it is demonstrated that reduced energy maneuvers are only attainable though the application of null-motions, which requires control of the reaction wheels. A computationally light formulation is developed minimizing the dissipative losses through the application of null motions. In the situation where the reaction wheels can not be directly controlled, it is demonstrated that energy consumption, dissipative losses, and peak-power loads, of the reaction-wheel array can each be reduced substantially by controlling the input to the attitude control system through attitude steering. It is demonstrated that the open loop trajectories correctly predict the closed loop response when tracked by an attitude control system which does not allow direct command of the reaction wheels.

Frequency-tuning input-shaped manifold-based switching control for underactuated space robot equipped with flexible appendages

NASA Astrophysics Data System (ADS)

Kojima, Hirohisa; Ieda, Shoko; Kasai, Shinya

2014-08-01

Underactuated control problems, such as the control of a space robot without actuators on the main body, have been widely investigated. However, few studies have examined attitude control problems of underactuated space robots equipped with a flexible appendage, such as solar panels. In order to suppress vibration in flexible appendages, a zero-vibration input-shaping technique was applied to the link motion of an underactuated planar space robot. However, because the vibrational frequency depends on the link angles, simple input-shaping control methods cannot sufficiently suppress the vibration. In this paper, the dependency of the vibrational frequency on the link angles is measured experimentally, and the time-delay interval of the input shaper is then tuned based on the frequency estimated from the link angles. The proposed control method is referred to as frequency-tuning input-shaped manifold-based switching control (frequency-tuning IS-MBSC). The experimental results reveal that frequency-tuning IS-MBSC is capable of controlling the link angles and the main body attitude to maintain the target angles and that the vibration suppression performance of the proposed frequency-tuning IS-MBSC is better than that of a non-tuning IS-MBSC, which does not take the frequency variation into consideration.

Integrated Orbit and Attitude Control for a Nanosatellite with Power Constraints

NASA Technical Reports Server (NTRS)

Naasz, Bo; Hall, Christopher; Berry, Matthew; Hy-Young, Kim

2003-01-01

Small satellites tend to be power-limited, so that actuators used to control the orbit and attitude must compete with each other as well as with other subsystems for limited electrical power. The Virginia Tech nanosatellite project, HokieSat, must use its limited power resources to operate pulsed-plasma thrusters for orbit control and magnetic torque coils for attitude control, while also providing power to a GPS receiver, a crosslink transceiver, and other subsystems. The orbit and attitude control strategies were developed independently. The attitude control system is based on an application of Linear Quadratic Regulator (LQR) to an averaged system of equations, whereas the orbit control is based on orbit element feedback. In this paper we describe the strategy for integrating these two control systems and present simulation results to verify the strategy.

Trying to trust: Brain activity during interpersonal social attitude change.

PubMed

Filkowski, Megan M; Anderson, Ian W; Haas, Brian W

2016-04-01

Interpersonal trust and distrust are important components of human social interaction. Although several studies have shown that brain function is associated with either trusting or distrusting others, very little is known regarding brain function during the control of social attitudes, including trust and distrust. This study was designed to investigate the neural mechanisms involved when people attempt to control their attitudes of trust or distrust toward another person. We used a novel control-of-attitudes fMRI task, which involved explicit instructions to control attitudes of interpersonal trust and distrust. Control of trust or distrust was operationally defined as changes in trustworthiness evaluations of neutral faces before and after the control-of-attitudes fMRI task. Overall, participants (n = 60) evaluated faces paired with the distrust instruction as being less trustworthy than faces paired with the trust instruction following the control-of-distrust task. Within the brain, both the control-of-trust and control-of-distrust conditions were associated with increased temporoparietal junction, precuneus (PrC), inferior frontal gyrus (IFG), and medial prefrontal cortex activity. Individual differences in the control of trust were associated with PrC activity, and individual differences in the control of distrust were associated with IFG activity. Together, these findings identify a brain network involved in the explicit control of distrust and trust and indicate that the PrC and IFG may serve to consolidate interpersonal social attitudes.

Attitude control challenges for earth orbiters of the 1980's

NASA Technical Reports Server (NTRS)

Hibbard, W.

1980-01-01

Experience gained in designing attitude control systems for orbiting spacecraft of the late 1980's is related. Implications for satellite attitude control design of the guidance capabilities, rendezvous and recovery requirements, use of multiple-use spacecraft and the development of large spacecraft associated with the advent of the Space Shuttle are considered. Attention is then given to satellite attitude control requirements posed by the Tracking and Data Relay Satellite System, the Global Positioning System, the NASA End-to-End Data System, and Shuttle-associated subsatellites. The anticipated completion and launch of the Space Telescope, which will provide one of the first experiences with the new generation of attitude control, is also pointed out.

Users of withdrawal method in the Islamic Republic of Iran: are they intending to use oral contraceptives? Applying the theory of planned behaviour.

PubMed

Rahnama, P; Hidarnia, A; Shokravi, F A; Kazemnejad, A; Montazeri, A; Najorkolaei, F R; Saburi, A

2013-09-01

Many couples in the Islamic Republic of Iran rely on coital withdrawal for contraception. The purpose of this cross-sectional study was to use the theory of planned behaviour to explore factors that influence withdrawal users' intent to switch to oral contraception (OC). Participants were 336 sexually active, married women, who were current users of withdrawal and were recruited from 5 public family planning clinics in Tehran. A questionnair included measures of the theory of planned behaviour: attitude (behavioural beliefs, outcome evaluations), subjective norms (normative beliefs, motivation to comply), perceived behaviour control, past behaviour and behavioural intention. Linear regression analyses showed that past behaviour, perceived behaviour control, attitude and subjective norms accounted for the highest percentage of total variance observed for intention to use OC (36%). Beliefs-based family planning education and counsellingshould to be designed for users of the withdrawal method.

Self-Regulation and Implicit Attitudes Toward Physical Activity Influence Exercise Behavior.

PubMed

Padin, Avelina C; Emery, Charles F; Vasey, Michael; Kiecolt-Glaser, Janice K

2017-08-01

Dual-process models of health behavior posit that implicit and explicit attitudes independently drive healthy behaviors. Prior evidence indicates that implicit attitudes may be related to weekly physical activity (PA) levels, but the extent to which self-regulation attenuates this link remains unknown. This study examined the associations between implicit attitudes and self-reported PA during leisure time among 150 highly active young adults and evaluated the extent to which effortful control (one aspect of self-regulation) moderated this relationship. Results indicated that implicit attitudes toward exercise were unrelated to average workout length among individuals with higher effortful control. However, those with lower effortful control and more negative implicit attitudes reported shorter average exercise sessions compared with those with more positive attitudes. Implicit and explicit attitudes were unrelated to total weekly PA. A combination of poorer self-regulation and negative implicit attitudes may leave individuals vulnerable to mental and physical health consequences of low PA.

The effect of active learning on student characteristics in a human physiology course for nonmajors.

PubMed

Wilke, R Russell

2003-12-01

This study investigated the effect of active-learning strategies on college students' achievement, motivation, and self-efficacy in a human physiology course for nonmajors. Variables were studied via a quasi-experimental, Solomon four-group design on 141 students at a small west-Texas university. Treatment groups were taught using a continuum-based, active-learning model implemented over the course of a semester. Control groups were taught using traditional didactic lecture methods. To assess the effects of the continuum-based active learning strategies, students were administered a comprehensive physiology content exam, the Motivated Strategies for Learning Questionnaire, and attitude surveys. Factorial analyses indicated that the treatment groups acquired significantly more content knowledge and were significantly more self-efficacious than students in the control groups. There were no significant differences in motivation. Attitude surveys indicated that students in both the treatment and control groups demonstrated a positive attitude toward active learning, believed it helped (or would help) them to learn the material, and would choose an active learning course in the future.

Autonomous control system reconfiguration for spacecraft with non-redundant actuators

NASA Astrophysics Data System (ADS)

Grossman, Walter

1995-05-01

The Small Satellite Technology Initiative (SSTI) 'CLARK' spacecraft is required to be single-failure tolerant, i.e., no failure of any single component or subsystem shall result in complete mission loss. Fault tolerance is usually achieved by implementing redundant subsystems. Fault tolerant systems are therefore heavier and cost more to build and launch than non-redundent, non fault-tolerant spacecraft. The SSTI CLARK satellite Attitude Determination and Control System (ADACS) achieves single-fault tolerance without redundancy. The attitude determination system system uses a Kalman Filter which is inherently robust to loss of any single attitude sensor. The attitude control system uses three orthogonal reaction wheels for attitude control and three magnetic dipoles for momentum control. The nominal six-actuator control system functions by projecting the attitude correction torque onto the reaction wheels while a slower momentum management outer loop removes the excess momentum in the direction normal to the local B field. The actuators are not redundant so the nominal control law cannot be implemented in the event of a loss of a single actuator (dipole or reaction wheel). The spacecraft dynamical state (attitude, angular rate, and momentum) is controllable from any five-element subset of the six actuators. With loss of an actuator the instantaneous control authority may not span R(3) but the controllability gramian integral(limits between t,0) Phi(t, tau)B(tau )B(prime)(tau) Phi(prime)(t, tau)d tau retains full rank. Upon detection of an actuator failure the control torque is decomposed onto the remaining active axes. The attitude control torque is effected and the over-orbit momentum is controlled. The resulting control system performance approaches that of the nominal system.

Sine Rotation Vector Method for Attitude Estimation of an Underwater Robot

PubMed Central

Ko, Nak Yong; Jeong, Seokki; Bae, Youngchul

2016-01-01

This paper describes a method for estimating the attitude of an underwater robot. The method employs a new concept of sine rotation vector and uses both an attitude heading and reference system (AHRS) and a Doppler velocity log (DVL) for the purpose of measurement. First, the acceleration and magnetic-field measurements are transformed into sine rotation vectors and combined. The combined sine rotation vector is then transformed into the differences between the Euler angles of the measured attitude and the predicted attitude; the differences are used to correct the predicted attitude. The method was evaluated according to field-test data and simulation data and compared to existing methods that calculate angular differences directly without a preceding sine rotation vector transformation. The comparison verifies that the proposed method improves the attitude estimation performance. PMID:27490549

Influenza Vaccination Coverage Among School Employees: Assessing Knowledge, Attitudes, and Behaviors

PubMed Central

de Perio, Marie A.; Wiegand, Douglas M.; Brueck, Scott E.

2015-01-01

BACKGROUND Influenza can spread among students, teachers, and staff in school settings. Vaccination is the most effective method to prevent influenza. We determined 2012–2013 influenza vaccination coverage among school employees, assessed knowledge and attitudes regarding the vaccine, and determined factors associated with vaccine receipt. METHODS We surveyed 412 (49%) of 841 employees at 1 suburban Ohio school district in March 2013. The Web-based survey assessed personal and work characteristics, vaccine receipt, and knowledge and attitudes regarding the vaccine. RESULTS Overall, 238 (58%) respondents reported getting the 2012–2013 influenza vaccine. The most common reason for getting the vaccine was to protect oneself or one’s family (87%). Beliefs that the vaccine was not needed (32%) or that it was not effective (21%) were the most common reasons for not getting it. Factors independently associated with vaccine receipt were having positive attitudes toward the vaccine, feeling external pressure to get it, and feeling personal control over whether to get it. CONCLUSIONS Influenza vaccine coverage among school employees should be improved. Messages encouraging school employees to get the vaccine should address misconceptions about the vaccine. Employers should use methods to maximize employee vaccination as part of a comprehensive influenza prevention program. PMID:25117893

A case study in nonlinear dynamics and control of articulated spacecraft: The Space Station Freedom with a mobile remote manipulator system

NASA Technical Reports Server (NTRS)

Bennett, William H.; Kwatny, Harry G.; Lavigna, Chris; Blankenship, Gilmer

1994-01-01

The following topics are discussed: (1) modeling of articulated spacecraft as multi-flex-body systems; (2) nonlinear attitude control by adaptive partial feedback linearizing (PFL) control; (3) attitude dynamics and control for SSF/MRMS; and (4) performance analysis results for attitude control of SSF/MRMS.

The Efficacy of Three Learning Methods Collaborative, Context-Based Learning and Traditional, on Learning, Attitude and Behaviour of Undergraduate Nursing Students: Integrating Theory and Practice

PubMed Central

Hasanpour-Dehkordi, Ali

2016-01-01

Introduction Communication skills training, responsibility, respect, and self-awareness are important indexes of changing learning behaviours in modern approaches. Aim The aim of this study was to investigate the efficacy of three learning approaches, collaborative, context-based learning (CBL), and traditional, on learning, attitude, and behaviour of undergraduate nursing students. Materials and Methods This study was a clinical trial with pretest and post-test of control group. The participants were senior nursing students. The samples were randomly assigned to three groups; CBL, collaborative, and traditional. To gather data a standard questionnaire of students’ behaviour and attitude was administered prior to and after the intervention. Also, the rate of learning was investigated by a researcher-developed questionnaire prior to and after the intervention in the three groups. Results In CBL and collaborative training groups, the mean score of behaviour and attitude increased after the intervention. But no significant association was obtained between the mean scores of behaviour and attitude prior to and after the intervention in the traditional group. However, the mean learning score increased significantly in the CBL, collaborative, and traditional groups after the study in comparison to before the study. Conclusion Both CBL and collaborative approaches were useful in terms of increased respect, self-awareness, self-evaluation, communication skills and responsibility as well as increased motivation and learning score in comparison to traditional method. PMID:27190926

VizieR Online Data Catalog: Astrometric observations of Phobos (Pasewaldt+, 2015)

NASA Astrophysics Data System (ADS)

Pasewaldt, A.; Oberst, J.; Willner, K.; Beisembin, B.; Hoffmann, H.; Matz, K. D.; Roatsch, T.; Michael, G.; Cardesin-Moinelo, A.; Zubarev, A. E.

2015-04-01

The data is given in the form of two tables. Each table contains the same set of observations: Data in tablea1.dat has been reduced using MEX navigation orbits and predicted attitude by the European Space Operations Centre (ESOC). tablea2.dat data has been derived using MEX accurate orbits by the Royal Observatory of Belgium (ROB) and measured attitude by the European Space Astronomy Centre (ESAC). >From 158 astrometric observations 103 were determined by means of both methods, 27 using only control point measurements, and 28 performing only limb fit observations. Hence, each data table contains 261 entries, namely 130 control point measurements and 131 limb fit observations. (2 data files).

Synchronization of multiple 3-DOF helicopters under actuator faults and saturations with prescribed performance.

PubMed

Yang, Huiliao; Jiang, Bin; Yang, Hao; Liu, Hugh H T

2018-04-01

The distributed cooperative control strategy is proposed to make the networked nonlinear 3-DOF helicopters achieve the attitude synchronization in the presence of actuator faults and saturations. Based on robust adaptive control, the proposed control method can both compensate the uncertain partial loss of control effectiveness and deal with the system uncertainties. To address actuator saturation problem, the control scheme is designed to ensure that the saturation constraint on the actuation will not be violated during the operation in spite of the actuator faults. It is shown that with the proposed control strategy, both the tracking errors of the leading helicopter and the attitude synchronization errors of each following helicopter are bounded in the existence of faulty actuators and actuator saturations. Moreover, the state responses of the entire group would not exceed the predesigned performance functions which are totally independent from the underlaying interaction topology. Simulation results illustrate the effectiveness of the proposed control scheme. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Single Axis Attitude Control and DC Bus Regulation with Two Flywheels

NASA Technical Reports Server (NTRS)

Kascak, Peter E.; Jansen, Ralph H.; Kenny, Barbara; Dever, Timothy P.

2002-01-01

A computer simulation of a flywheel energy storage single axis attitude control system is described. The simulation models hardware which will be experimentally tested in the future. This hardware consists of two counter rotating flywheels mounted to an air table. The air table allows one axis of rotational motion. An inertia DC bus coordinator is set forth that allows the two control problems, bus regulation and attitude control, to be separated. Simulation results are presented with a previously derived flywheel bus regulator and a simple PID attitude controller.

Attitude ground support system for the solar maximum mission spacecraft

NASA Technical Reports Server (NTRS)

Nair, G.

1980-01-01

The SMM attitude ground support system (AGSS) supports the acquisition of spacecraft roll attitude reference, performs the in-flight calibration of the attitude sensor complement, supports onboard control autonomy via onboard computer data base updates, and monitors onboard computer (OBC) performance. Initial roll attitude acquisition is accomplished by obtaining a coarse 3 axis attitude estimate from magnetometer and Sun sensor data and subsequently refining it by processing data from the fixed head star trackers. In-flight calibration of the attitude sensor complement is achieved by processing data from a series of slew maneuvers designed to maximize the observability and accuracy of the appropriate alignments and biases. To ensure autonomy of spacecraft operation, the AGSS selects guide stars and computes sensor occultation information for uplink to the OBC. The onboard attitude control performance is monitored on the ground through periodic attitude determination and processing of OBC data in downlink telemetry. In general, the control performance has met mission requirements. However, software and hardware problems have resulted in sporadic attitude reference losses.

Knowledge, Attitude and Practices of Diabetic Patients in the United Arab Emirates

PubMed Central

Al-Maskari, Fatma; El-Sadig, Mohamed; Al-Kaabi, Juma M.; Afandi, Bachar; Nagelkerke, Nicolas; Yeatts, Karin B.

2013-01-01

Introduction Diabetes self-management education is a cornerstone of diabetes care. However, many diabetics in the United Arab Emirates (UAE) lack sufficient knowledge about their disease due to illiteracy. Thus, before considering any possible intervention it was imperative to assess present knowledge, attitudes, and practices of patients towards the management of diabetes. Methods A random sample of 575 DM patients was selected from diabetes outpatient's clinics of Tawam and Al-Ain hospitals in Al-Ain city (UAE) during 2006–2007, and their knowledge attitude and practice assessed using a questionnaire modified from the Michigan Diabetes Research Training Center instrument. Results Thirty-one percent of patients had poor knowledge of diabetes. Seventy-two had negative attitudes towards having the disease and 57% had HbA1c levels reflecting poor glycemic control. Only seventeen percent reported having adequate blood sugar control, while 10% admitted non-compliance with their medications. Knowledge, practice and attitude scores were all statistically significantly positively, but rather weakly, associated, but none of these scores was significantly correlated with HbA1c. Conclusions The study showed low levels of diabetes awareness but positive attitudes towards the importance of DM care and satisfactory diabetes practices in the UAE. Programs to increase patients' awareness about DM are essential for all diabetics in the UAE in order to improve their understanding, compliance and management and, thereby, their ability to cope with the disease. PMID:23341913

Rationale, design and methods for a staggered-entry, waitlist controlled clinical trial of the impact of a community-based, family-centred, multidisciplinary program focussed on activity, food and attitude habits (Curtin University’s Activity, Food and Attitudes Program—CAFAP) among overweight adolescents

PubMed Central

2012-01-01

Background Current estimates place just under one quarter of adolescents in Australia as overweight or obese. Adolescence has been identified as a critical period for the development of obesity, yet despite this recognition, there is limited systematic research into or evaluation of interventions for overweight adolescents. Reviews have concluded that there is a substantive evidence gap for effective intervention, but physical activity, lifestyle change and family involvement have been identified as promising foci for treatment. Methods This paper reports on the development of a staggered-entry, waitlist controlled clinical trial to assess the impact of a multidisciplinary intervention aiming to change the poor health trajectory of overweight adolescents and help them avoid morbid obesity in adulthood—Curtin University’s Activity, Food and Attitudes Program (CAFAP). 96 adolescents, aged 11–16 years, and parents, will attend twice weekly during an 8 week intensive multidisciplinary program with maintenance follow-up focussed on improving activity, food and attitude habits. Follow-up assessments will be conducted immediately after completing the intensive program, and at 3, 6 and 12 months post intensive program. Main outcomes will be objectively-measured physical activity, sedentary behaviour and activity behaviours; food intake (measured by 3 day diary) and food behaviours; body composition, fitness and physical function; mental and social well-being (quality of life, mood and attitudes), and family functioning. Discussion This trial will provide important information to understand whether a community based multidisciplinary intervention can have short and medium term effects on activity and food habits, attitudes, and physical and mental health status of overweight adolescents. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12611001187932. PMID:22721261

A Simple Attitude Control of Quadrotor Helicopter Based on Ziegler-Nichols Rules for Tuning PD Parameters

PubMed Central

He, ZeFang

2014-01-01

An attitude control strategy based on Ziegler-Nichols rules for tuning PD (proportional-derivative) parameters of quadrotor helicopters is presented to solve the problem that quadrotor tends to be instable. This problem is caused by the narrow definition domain of attitude angles of quadrotor helicopters. The proposed controller is nonlinear and consists of a linear part and a nonlinear part. The linear part is a PD controller with PD parameters tuned by Ziegler-Nichols rules and acts on the quadrotor decoupled linear system after feedback linearization; the nonlinear part is a feedback linearization item which converts a nonlinear system into a linear system. It can be seen from the simulation results that the attitude controller proposed in this paper is highly robust, and its control effect is better than the other two nonlinear controllers. The nonlinear parts of the other two nonlinear controllers are the same as the attitude controller proposed in this paper. The linear part involves a PID (proportional-integral-derivative) controller with the PID controller parameters tuned by Ziegler-Nichols rules and a PD controller with the PD controller parameters tuned by GA (genetic algorithms). Moreover, this attitude controller is simple and easy to implement. PMID:25614879

Attitudes of cancer patients, family caregivers, oncologists and members of the general public toward critical interventions at the end of life of terminally ill patients

PubMed Central

Yun, Young Ho; Han, Kyung Hee; Park, Sohee; Park, Byeong Woo; Cho, Chi-Heum; Kim, Sung; Lee, Dae Ho; Lee, Soon Nam; Lee, Eun Sook; Kang, Jung Hun; Kim, Si-Young; Lee, Jung Lim; Heo, Dae Seog; Lee, Chang Geol; Lim, Yeun Keun; Kim, Sam Yong; Choi, Jong Soo; Jeong, Hyun Sik; Chun, Mison

2011-01-01

Background: Whereas most studies have focused on euthanasia and physician-assisted suicide, few have dealt comprehensively with other critical interventions administered at the end of life. We surveyed cancer patients, family caregivers, oncologists and members of the general public to determine their attitudes toward such interventions. Methods: We administered a questionnaire to four groups about their attitudes toward five end-of-life interventions — withdrawal of futile life-sustaining treatment, active pain control, withholding of life-sustaining measures, active euthanasia and physician-assisted suicide. We performed multivariable analyses to compare attitudes and to identify sociodemographic characteristics associated with the attitudes. Results: A total of 3840 individuals — 1242 cancer patients, 1289 family caregivers and 303 oncologists from 17 hospitals, as well as 1006 members of the general Korean population — participated in the survey. A large majority in each of the groups supported withdrawal of futile life-sustaining treatment (87.1%–94.0%) and use of active pain control (89.0%–98.4%). A smaller majority (60.8%–76.0%) supported withholding of life-sustaining treatment. About 50% of those in the patient and general population groups supported active euthanasia or physician-assisted suicide, as compared with less than 40% of the family caregivers and less than 10% of the oncologists. Higher income was significantly associated with approval of the withdrawal of futile life-sustaining treatment and the practice of active pain control. Older age, male sex and having no religion were significantly associated with approval of withholding of life-sustaining measures. Older age, male sex, having no religion and lower education level were significantly associated with approval of active euthanasia and physician-assisted suicide. Interpretation: Although the various participant groups shared the same attitude toward futile and ameliorative end-of-life care (the withdrawal of futile life-sustaining treatment and the use of active pain control), oncologists had a more negative attitude than those in the other groups toward the active ending of life (euthanasia and physician-assisted suicide). PMID:21624907

Medical student, nursing student, and non-health care respondents' implicit attitudes toward doctors and patients: Development and a pilot study of a new implicit attitudes test (IAT).

PubMed

Schwartz, Alan; Mazouni, Abdelhamid

2017-01-01

Medical educators have been concerned that medical students may decline in empathy for patients during the course of their training, based on studies measuring clinical empathy using psychometrically strong self-report measures. Clinical empathy is a complex construct, incorporating attitudes toward patients but also other components, such as professional detachment. Triangulation of extant measures with instruments based on nonreactive methods could provide a better understanding of whether and how physician attitudes toward patients may be changing during training. We sought to develop and pilot-test such a nonreactive method. We develop variations of an implicit association test (IAT) designed to measure attitudes toward physicians and patients based on speed of reaction to images of actors and positive and negative words. In the IATs, the same actors are photographed as doctors, clinic outpatients, hospitalized inpatients, and as a "general public" control. We examine preliminary evidence for their validity by collecting pilot data from internet participants (not involved in the health professions), medical students, and nursing students. Internet participants (n = 314) and nursing students (n = 31) had more negative associations (IAT scores) with doctors than did medical students (n = 89); nursing students and female internet participants had more positive associations with hospitalized patients than did medical students and male internet participants. Medical students' associations with hospitalized patients varied by year of training. This IAT may provide insight into implicit attitudes among those who enter training for the health profession and changes in those attitudes that may be inculcated during that training.

X-33 Attitude Control System Design for Ascent, Transition, and Entry Flight Regimes

NASA Technical Reports Server (NTRS)

Hall, Charles E.; Gallaher, Michael W.; Hendrix, Neal D.

1998-01-01

The Vehicle Control Systems Team at Marshall Space Flight Center, Systems Dynamics Laboratory, Guidance and Control Systems Division is designing under a cooperative agreement with Lockheed Martin Skunkworks, the Ascent, Transition, and Entry flight attitude control system for the X-33 experimental vehicle. Ascent flight control begins at liftoff and ends at linear aerospike main engine cutoff (NECO) while Transition and Entry flight control begins at MECO and concludes at the terminal area energy management (TAEM) interface. TAEM occurs at approximately Mach 3.0. This task includes not only the design of the vehicle attitude control systems but also the development of requirements for attitude control system components and subsystems. The X-33 attitude control system design is challenged by a short design cycle, the design environment (Mach 0 to about Mach 15), and the X-33 incremental test philosophy. The X-33 design-to-launch cycle of less than 3 years requires a concurrent design approach while the test philosophy requires design adaptation to vehicle variations that are a function of Mach number and mission profile. The flight attitude control system must deal with the mixing of aerosurfaces, reaction control thrusters, and linear aerospike engine control effectors and handle parasitic effects such as vehicle flexibility and propellant sloshing from the uniquely shaped propellant tanks. The attitude control system design is, as usual, closely linked to many other subsystems and must deal with constraints and requirements from these subsystems.

ATS-6 engineering performance report. Volume 2: Orbit and attitude controls

NASA Technical Reports Server (NTRS)

Wales, R. O. (Editor)

1981-01-01

Attitude control is reviewed, encompassing the attitude control subsystem, spacecraft attitude precision pointing and slewing adaptive control experiment, and RF interferometer experiment. The spacecraft propulsion system (SPS) is discussed, including subsystem, SPS design description and validation, orbital operations and performance, in-orbit anomalies and contingency operations, and the cesium bombardment ion engine experiment. Thruster failure due to plugging of the propellant feed passages, a major cause for mission termination, are considered among the critical generic failures on the satellite.

Attitude Control Propulsion Components, Volume 1

NASA Technical Reports Server (NTRS)

1974-01-01

Effort was made to include as much engineering information on each component as possible, consistent with usefulness and catalog size limitations. The contents of this catalog contain components which were qualified for use with spacecraft monopropellant hydrazine and inert gas attitude control systems. Thrust ranges up to 44.5 N (10.0 lbf) for hydrazine and inert gas sytems were considered. Additionally, some components qualified for uses other than spacecraft attitude control are included because they are suitable for use in attitude controls systems.

Adaptive Jacobian Fuzzy Attitude Control for Flexible Spacecraft Combined Attitude and Sun Tracking System

NASA Astrophysics Data System (ADS)

Chak, Yew-Chung; Varatharajoo, Renuganth

2016-07-01

Many spacecraft attitude control systems today use reaction wheels to deliver precise torques to achieve three-axis attitude stabilization. However, irrecoverable mechanical failure of reaction wheels could potentially lead to mission interruption or total loss. The electrically-powered Solar Array Drive Assemblies (SADA) are usually installed in the pitch axis which rotate the solar arrays to track the Sun, can produce torques to compensate for the pitch-axis wheel failure. In addition, the attitude control of a flexible spacecraft poses a difficult problem. These difficulties include the strong nonlinear coupled dynamics between the rigid hub and flexible solar arrays, and the imprecisely known system parameters, such as inertia matrix, damping ratios, and flexible mode frequencies. In order to overcome these drawbacks, the adaptive Jacobian tracking fuzzy control is proposed for the combined attitude and sun-tracking control problem of a flexible spacecraft during attitude maneuvers in this work. For the adaptation of kinematic and dynamic uncertainties, the proposed scheme uses an adaptive sliding vector based on estimated attitude velocity via approximate Jacobian matrix. The unknown nonlinearities are approximated by deriving the fuzzy models with a set of linguistic If-Then rules using the idea of sector nonlinearity and local approximation in fuzzy partition spaces. The uncertain parameters of the estimated nonlinearities and the Jacobian matrix are being adjusted online by an adaptive law to realize feedback control. The attitude of the spacecraft can be directly controlled with the Jacobian feedback control when the attitude pointing trajectory is designed with respect to the spacecraft coordinate frame itself. A significant feature of this work is that the proposed adaptive Jacobian tracking scheme will result in not only the convergence of angular position and angular velocity tracking errors, but also the convergence of estimated angular velocity to the actual angular velocity. Numerical results are presented to demonstrate the effectiveness of the proposed scheme in tracking the desired attitude, as well as suppressing the elastic deflection effects of solar arrays during maneuver.

Integrating family planning and HIV services in western Kenya: the impact on HIV-infected patients' knowledge of family planning and male attitudes toward family planning.

PubMed

Onono, Maricianah; Guzé, Mary A; Grossman, Daniel; Steinfeld, Rachel; Bukusi, Elizabeth A; Shade, Starley; Cohen, Craig R; Newmann, Sara J

2015-01-01

Little information exists on the impact of integrating family planning (FP) services into HIV care and treatment on patients' familiarity with and attitudes toward FP. We conducted a cluster-randomized trial in 18 public HIV clinics with 12 randomized to integrated FP and HIV services and 6 to the standard referral-based system where patients are referred to an FP clinic. Serial cross-sectional surveys were done before (n = 488 women, 486 men) and after (n = 479 women, 481 men) the intervention to compare changes in familiarity with FP methods and attitudes toward FP between integrated and nonintegrated (NI) sites. We created an FP familiarity score based on the number of more effective FP methods patients could identify (score range: 0-6). Generalized estimating equations were used to control for clustering within sites. An increase in mean familiarity score between baseline (mean = 5.16) and post-intervention (mean = 5.46) occurred with an overall mean change of 0.26 (95% confidence intervals [CI] = 0.09, 0.45; p = 0.003) across all sites. At end line, there was no difference in increase of mean FP familiarity scores at intervention versus control sites (mean = 5.41 vs. 5.49, p = 0.94). We observed a relative decrease in the proportion of males agreeing that FP was "women's business" at integrated sites (baseline 42% to end line 30%; reduction of 12%) compared to males at NI sites (baseline 35% to end line 42%; increase of 7%; adjusted odds ration [aOR] = 0.43; 95% CI = 0.22, 0.85). Following FP-HIV integration, familiarity with FP methods increased but did not differ by study arm. Integration was associated with a decrease in negative attitudes toward FP among men.

Controlled randomized clinical trial of spirituality integrated psychotherapy, cognitive-behavioral therapy and medication intervention on depressive symptoms and dysfunctional attitudes in patients with dysthymic disorder

PubMed Central

Ebrahimi, Amrollah; Neshatdoost, Hamid Taher; Mousavi, Seyed Ghafur; Asadollahi, Ghorban Ali; Nasiri, Hamid

2013-01-01

Background: Due to the controversy over efficacy of cognitive-behavioral therapy for chronic depression, recently, there has been an increasingly tendency toward therapeutic methods based on the cultural and spiritual approaches. The aim of this research was to compare efficacy of spiritual integrated psychotherapy (SIPT) and cognitive-behavioral therapy (CBT) on the intensity of depression symptoms and dysfunctional attitudes of patients with dysthymic disorder. Materials and Methods: This study had a mixed qualitative and quantitative design. In the first phase, SIPT model was prepared and, in the second phase, a double-blind random clinical trial was performed. Sixty-two patients with dysthymic disorder were selected from several centers include Nour and Alzahra Medical Center, Counseling Centers of Isfahan University of Medical Sciences and Goldis in Isfahan. The participants were randomly assigned to three experimental groups and one control group. The first group received 8 sessions treatment of SIPT, second groups also had 8 sessions of cognitive-behavioral therapy, which was specific to dysthymic disorder and third group were under antidepressant treatment. Beck depression inventory and dysfunctional attitudes scale were used to evaluate all the participants in four measurement stages. The data were analyzed using MANCOVA repeated measure method. Results: The results revealed that SIPT had more efficacy than medication based on both scales (P < 0.01); however, it was not different from CBT. SIPT was more effective on the modification of dysfunctional attitudes compared with CBT and medication (P < 0.05). Conclusion: These findings supported the efficacy of psychotherapy enriched with cultural capacities and religious teachings. PMID:24516853

A new momentum management controller for the space station

NASA Technical Reports Server (NTRS)

Wie, B.; Byun, K. W.; Warren, V. W.

1988-01-01

A new approach to CMG (control moment gyro) momentum management and attitude control of the Space Station is developed. The control algorithm utilizes both the gravity-gradient and gyroscopic torques to seek torque equilibrium attitude in the presence of secular and cyclic disturbances. Depending upon mission requirements, either pitch attitude or pitch-axis CMG momentum can be held constant: yaw attitude and roll-axis CMG momentum can be held constant, while roll attitude and yaw-axis CMG momentum cannot be held constant. As a result, the overall attitude and CMG momentum oscillations caused by cyclic aero-dynamic disturbances are minimized. A state feedback controller with minimal computer storage requirement for gain scheduling is also developed. The overall closed-loop system is stable for + or - 30 percent inertia matrix variations and has more than + or - 10 dB and 45 deg stability margins in each loop.

Research on Design of MUH Attitude Stability Augmentation Control System

NASA Astrophysics Data System (ADS)

Fan, Shigang

2017-09-01

Attitude stability augmentation control system with a lower cost need to be designed so that MUH (Mini Unmanned Helicopter) can adapt to different types of geographic environment and fly steadily although the weather may be bad. Attitude feedback was calculated mainly by filtering estimation within attitude acquisition module in this system. Stability augmentation can be improved mainly by PI. This paper will depict running principle and designing process of MUH attitude stability augmentation control system and algorithm that is considered as an important part in this system.

Finite-horizon control-constrained nonlinear optimal control using single network adaptive critics.

PubMed

Heydari, Ali; Balakrishnan, Sivasubramanya N

2013-01-01

To synthesize fixed-final-time control-constrained optimal controllers for discrete-time nonlinear control-affine systems, a single neural network (NN)-based controller called the Finite-horizon Single Network Adaptive Critic is developed in this paper. Inputs to the NN are the current system states and the time-to-go, and the network outputs are the costates that are used to compute optimal feedback control. Control constraints are handled through a nonquadratic cost function. Convergence proofs of: 1) the reinforcement learning-based training method to the optimal solution; 2) the training error; and 3) the network weights are provided. The resulting controller is shown to solve the associated time-varying Hamilton-Jacobi-Bellman equation and provide the fixed-final-time optimal solution. Performance of the new synthesis technique is demonstrated through different examples including an attitude control problem wherein a rigid spacecraft performs a finite-time attitude maneuver subject to control bounds. The new formulation has great potential for implementation since it consists of only one NN with single set of weights and it provides comprehensive feedback solutions online, though it is trained offline.

Knowledge, attitude and practice of standard precautions of infection control by hospital workers in two tertiary hospitals in Nigeria

PubMed Central

Pondei, Kemebradikumo; Adetunji, Babatunde; Chima, George; Isichei, Christian; Gidado, Sanusi

2015-01-01

Background: Standard precautions are recommended to prevent transmission of infection in hospitals. However, their implementation is dependent on the knowledge and attitudes of healthcare workers (HCW). This study describes the knowledge, attitude and practice (KAP) of standard precautions of infection control among HCW of two tertiary hospitals in Nigeria is described. Methods: A cross-sectional study was undertaken in 2011/2012 among HCW in two tertiary hospitals in Nigeria. Data was collected via a structured self-administered questionnaire assessing core elements of KAP of standard precautions. Percentage KAP scores were calculated and professional differences in median percentage KAP scores were ascertained. Results: A total of 290 HCW participated in the study (76% response rate), including 111 (38.3%) doctors, 147 (50.7%) nurses and 32 (11%) laboratory scientists. Overall median knowledge and attitude scores toward standard precautions were above 90%, but median practice score was 50.8%. The majority of the HCW had poor knowledge of injection safety and complained of inadequate resources to practise standard precautions. House officers, laboratory scientists and junior cadres of nurses had lower knowledge and compliance with standard precautions than more experienced doctors and nurses. Conclusion: Our results suggest generally poor compliance with standard precautions of infection control among HCW in Nigeria. Policies that foster training of HCW in standard precautions and guarantee regular provision of infection control and prevention resources in health facilities are required in Nigeria. PMID:28989394

Steady-state simulation program for attitude control propulsion systems

NASA Technical Reports Server (NTRS)

Heinmiller, P. J.

1973-01-01

The formulation and the engineering equations employed in the steady state attitude control propulsion system simulation program are presented. The objective of this program is to aid in the preliminary design and development of propulsion systems used for spacecraft attitude control. The program simulates the integrated operation of the many interdependent components typically comprising an attitude control propulsion system. Flexibility, generality, ease of operation, and speed consistent with adequate accuracy were overriding considerations during the development of this program. Simulation modules were developed representing the various types of fluid components typically encountered in an attitude control propulsion system. These modules are basically self-contained and may be arranged by the program user into desired configuration through the program input data.

Knowledge, Attitudes, and Practice of Infection Control among Dental Students at Sana’a University, Yemen

PubMed Central

Halboub, Esam Saleh; Al-Maweri, Sadeq Ali; Al-Jamaei, Aisha Ahmed; Tarakji, Bassel; Al-Soneidar, Walid Ahmed

2015-01-01

Background: The aim of this study was to evaluate knowledge, attitudes, and practices regarding infection control procedures among senior dental students. Materials and Methods: A questionnaire-based cross-sectional survey was conducted among 145 4th- and 5th-year dental students at the Faculty of Dentistry, Sana’a University, Yemen. The self-administered questionnaire was comprised of 20 open- and close-ended items regarding barrier techniques, vaccination status, infection control practices, and awareness. Data were analyzed with a Chi-square test. A P ≤ 0.05 was considered significant. Results: The response rate was 72% (145 out of 204 potential respondents). Overall, 71.7% of the students had been vaccinated for hepatitis B and only 9.5% were tested for post-hepatitis B virus immunization serology. While the vast majority (96.6%) reported always wearing gloves for all dental procedures, the use of face masks and eyewear were reported by only 53.8% and 14.0% of students, respectively, with no significant difference between genders and year of study (P > 0.05). A significantly higher percentage of 5th-year students (58.9%) showed positive attitudes toward the treatment of patients with infectious diseases, as compared to only 31.0% of 4th year students (P < 0.01). A great number of students (62%) reported non-sterile occupational percutaneous and mucous injuries while treating their patients. Conclusions: These unsatisfactory findings highlight the necessity of continued infection control education in order to improve knowledge, attitudes, and practices regarding infection control among dental students at Sana’a University. PMID:26028896

Evaluating a Control System Architecture Based on a Formally Derived AOCS Model

NASA Astrophysics Data System (ADS)

Ilic, Dubravka; Latvala, Timo; Varpaaniemi, Kimmo; Vaisanen, Pauli; Troubitsyna, Elena; Laibinis, Linas

2010-08-01

Attitude & Orbit Control System (AOCS) refers to a wider class of control systems which are used to determine and control the attitude of the spacecraft while in orbit, based on the information obtained from various sensors. In this paper, we propose an approach to evaluate a typical (yet somewhat simplified) AOCS architecture using formal development - based on the Event-B method. As a starting point, an Ada specification of the AOCS is translated into a formal specification and further refined to incorporate all the details of its original source code specification. This way we are able not only to evaluate the Ada specification by expressing and verifying specific system properties in our formal models, but also to determine how well the chosen modelling framework copes with the level of detail required for an actual implementation and code generation from the derived models.

Measuring attitude with a gradiometer

NASA Technical Reports Server (NTRS)

Sonnabend, David; Gardner, Thomas G.

1994-01-01

This paper explores using a gravity gradiometer to measure the attitude of a satellite, given that the gravity field is accurately known. Since gradiometers actually measure a combination of the gradient and attitude rate and acceleration terms, the answer is far from obvious. The paper demonstrates that it can be done and at microradian accuracy. The technique employed is dynamic estimation, based on the momentum biased Euler equations. The satellite is assumed nominally planet pointed, and subject to control, gravity gradient, and partly radom drag torques. The attitude estimator is unusual. While the standard method of feeding back measurement residuals is used, the feedback gain matrix isn't derived from Kalman theory. instead, it's chosen to minimize a measure of the terminal covariance of the error in the estimate. This depends on the gain matrix and the power spectra of all the process and measurement noises. An integration is required over multiple solutions of Lyapunov equations.

[Knowledge, attitude and practice on schistosomiasis control of chronic schistosomiasis patients in Poyang Lake area, Nanchang City].

PubMed

Guo-Hua, Peng; Zhu-Hua, Hu; Wei, Hua; Ke, Qian; Xiao-Gang, Li; Zhi-Shu, Zhang; Zhi-Gang, Chen; Xiao-Wu, Feng

2017-06-26

To understand the present situation of the chronic schistosomiasis patients' knowledge, attitude and practice on schistosomiasis control in Nanchang City. The knowledge, attitude and values on schistosomiasis control of 523 chronic schistosomiasis patients in Nanchang County, Jinxian County and Xinjian District in the Poyang Lake District were investigated with questionnaires. And the accuracy rates of the knowledge, attitude and practice among the patient groups of different counties, genders, age groups, occupations and educational levels were analyzed. The accuracy rates of the knowledge, attitude and practice of patients on schistosomiasis control were 95.76%, 82.80%, and 81.73% in Nanchang County; 91.37%, 93.32%, and 76.48% in Jinxian County; 88.25%, 67.56%, and 49.40% in Xinjian District. In the accuracy rates of knowledge, attitude and practice, the differences among the three counties (districts) were statistically significant ( χ 2 = 57.511-301.378, all P < 0.05) . The accuracy rates of chronic schistosomiasis patients' attitude and practice on schistosomiasis control in Nanchang City remain low. Therefore, the intensity of attitude and practice intervention should be strengthened in the Poyang Lake District in order to enhance the self-protection awareness of the patients.

Exposures Associated With Minority High Schoolers’ Predisposition for Health Science

PubMed Central

Boekeloo, Bradley; Brooks, Alyssa Todaro; Wang, Min Qi

2016-01-01

Objective To identify modifiable facilitation strategies (exposures) during high school that are associated with motivation for minority youth pursuit of health science. Methods A sample (N = 116) of minority (73% African American/Black, 21% Hispanic/Latino) 12th graders from 6 high schools in a lower socioeconomic area bordering Washington, DC completed a self-administered survey. Path modeling was used to examine whether: 1) exposures: high school science courses, extra-curricular science activities, personal health experiences, and adult encouragement predict Theory of Planned Behavior (TPB) constructs including Attitude, Subjective Norm, and Perceived Behavioral Control, and 2) TPB constructs predict the outcome of Intent to pursue college health science. Results The path model indicated that adult encouragement was associated with Attitude (p < .001), Subjective Norm (p < .001), and Perceived Behavioral Control (p < .001); and personal health experiences were associated with Attitude (p < .001). Attitude and Subjective Norm were associated with Intent (p < .001). Conclusion Motivating minority high schoolers from low socioeconomic areas through adult encouragement and personal health experiences to value health scientists and to perceive that others support their pursuit of health science may be pathways for facilitating their intention to pursue college health science. PMID:28452687

Attitude control of the LACE satellite: A gravity gradient stabilized spacecraft

NASA Technical Reports Server (NTRS)

Ivory, J. E.; Campion, R. E.; Bakeris, D. F.

1993-01-01

The Low-power Atmospheric Compensation Experiment (LACE) satellite was launched in February 1990 by the Naval Research Laboratory. The spacecraft's pitch and roll are maintained with a gravity gradient boom and a magnetic damper. There are two other booms with much smaller tip masses, one in the velocity direction (lead boom) of variable length and the other in the opposite direction (balance boom) also of variable length. In addition, the system uses a momentum wheel with its axis perpendicular to the plane of the orbit to control yaw and keep these booms in the orbital plane. The primary LACE experiment requires that the lead boom be moved to lengths varying from 4.6 m to 45.7 m. This and other onboard experiments require that the spacecraft attitude remain within tight constraints while operating. The problem confronting the satellite operators was to move the lead boom without inducing a net spacecraft attitude disturbance. A description of a method used to change the length of the lead boom while minimizing the disturbance to the attitude of the spacecraft is given. Deadbeating to dampen pitch oscillations has also been accomplished by maneuvering either the lead or balance boom and is discussed.

Psychological Aspects of Cosmetic Surgery among Females: A Media Literacy Training Intervention

PubMed Central

Khazir, Zahra; Dehdari, Tahereh; Majdabad, Mahmood Mahmoodi; Tehrani, Said Pournaghash

2016-01-01

Introduction: The present study examined the favorable attitude of a sample of female university students regarding elective cosmetic surgery, body dysmorphic disorder, self-esteem and body dissatisfaction following a media literacy training intervention. Methods: This study was a quasi-experimental type. The study sample included 140 female university students who were allocated to either the intervention (n=70) or the control group (n=70). Attitude toward cosmetic surgery, body dysmorphic disorder, self-esteem and, body satisfaction was measured in both groups before the intervention and 4 weeks later. Four media literacy training sessions were conducted over 4 weeks for the intervention group. The data was analyzed through analysis of covariance, student’s paired-samples t test, and Pearson correlation. Results: Our findings showed that favorable attitude, body dysmorphic disorder and body dissatisfaction scores were significantly lower (p<0.05) in the intervention group than the control group. Furthermore, self-esteem score increased significantly in the intervention group. Conclusions: Our results underscores the importance of media literacy intervention in decreasing female’s favorable attitude towards elective cosmetic surgery, body dysmorphic disorder and body dissatisfaction as well as increasing self-esteem. PMID:26383204

Assessing landowners' attitudes toward wild hogs and support for control options.

PubMed

Caplenor, Carlotta A; Poudyal, Neelam C; Muller, Lisa I; Yoest, Chuck

2017-10-01

Wild hogs (Sus scrofa) are an invasive species with destructive habits, particularly rooting and wallowing, which can directly impact agricultural crops, pasture land, and water quality. Considering wild hogs are widely dispersed across the landscape, they are extremely difficult to control. Disagreements can arise among different stakeholders over whether and how their populations should be managed. The purpose of this article was to examine Tennessee, United States landowners' attitudes toward wild hogs, to compare acceptability of control methods, and to evaluate factors significantly influencing public support for regulations to control wild hogs. Logistic regression was employed to analyze data collected from a statewide survey of rural landowners in the fall of 2015. Landowners had overwhelmingly negative attitudes towards wild hogs, and were concerned about their impact on the natural environment and rural economy. Although landowners showed support for controlling wild hogs, levels of acceptability for management options varied. Respondents favored active management and supported education and incentive-based control programs to control wild hogs. Cognitive concepts such as social and personal norms and awareness of consequences, as well as demographic characteristics, significantly predicted landowners' support for state regulations to control wild hogs in Tennessee. Findings increase our understanding of the human dimensions of wild hog management and that of other similarly invasive animals, and may guide resource managers in designing effective and socially acceptable management strategies to control wild hog populations in Tennessee and elsewhere. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of ethnoscience instruction, school location, and parental educational status on learners' attitude towards science

NASA Astrophysics Data System (ADS)

Fasasi, Rasheed Adekunle

2017-03-01

This study investigated the effect of Ethnoscience instruction and moderating effects of school location and parental educational status on students' attitude to science. It employed pretest-posttest, non-equivalent control group quasiexperimental design. Participants were 352 Junior Secondary School 1 (aged 9-12 years) students from two schools, each in urban and rural areas of Ìbàdàn, southwestern Nigeria. Instruments used are: Teachers Instructional Guide on Ethnoscience instruction, Teachers Instructional Guide on Modified Lecture Method and Attitude Toward Science Scale (r = 0.86). Three null hypotheses were tested at 0.05 level of significance. Data were analyzed using Analysis of Covariance. Significant main effect of treatment on attitude to science (F(1, 347) = 296, p < 0.05) was recorded, with Ethnoscience instruction group performing better than the Modified Lecture Method group. Effect size of treatment was strong (η2 p = 0.46). Also recorded were significant main effects of school location (F(1, 347) = 10.2, p < .05) and parental educational status (F(1, 347 = 3.37), p < 0.05) on students' attitude to science with weak effect sizes (η2 p = 0.029 and η2 p = 0.019 respectively). Learners in rural schools performed better than those in urban schools and those from lowly educated parents had better performance than highly educated parents. Ethnoscience instruction promoted learners' attitude to science. Therefore, its use in educational instruction, especially among traditional science learners, should be explored.

Detumbling control for kinematically redundant space manipulator post-grasping a rotational satellite

NASA Astrophysics Data System (ADS)

Wang, Mingming; Luo, Jianjun; Yuan, Jianping; Walter, Ulrich

2017-12-01

The objective of this paper is to establish a detumbling strategy and a coordination control scheme for a kinematically redundant space manipulator post-grasping a rotational satellite. First, the dynamics of the kinematically redundant space robot after grasping the target is presented, which lays the foundation for the coordination controller design. Subsequently, optimal detumbling and motion planning strategy for the post-capture phase is proposed based on the quartic Bézier curves and adaptive differential evolution (DE) algorithm subject to the specific constraints. Both detumbling time and control torques are taken into account for the generation of the optimal detumbling strategy. Furthermore, a coordination control scheme is presented to track the designed reference path while regulating the attitude of the chaser to a desired value, which successfully dumps the initial angular velocity of the rotational satellite and controls the base attitude synchronously. Simulation results are presented for detumbling a target with rotational motion using a 7 degree-of-freedom (DOF) redundant space manipulator, which demonstrates the effectiveness of the proposed method.

A blended-learning programme regarding professional ethics in physiotherapy students.

PubMed

Aguilar-Rodríguez, Marta; Marques-Sule, Elena; Serra-Añó, Pilar; Espí-López, Gemma Victoria; Dueñas-Moscardó, Lirios; Pérez-Alenda, Sofía

2018-01-01

In the university context, assessing students' attitude, knowledge and opinions when applying an innovative methodological approach to teach professional ethics becomes fundamental to know if the used approach is enough motivating for students. To assess the effect of a blended-learning model, based on professional ethics and related to clinical practices, on physiotherapy students' attitude, knowledge and opinions towards learning professional ethics. Research design and participants: A simple-blind clinical trial was performed (NLM identifier NCT03241693) (control group, n = 64; experimental group, n = 65). Both groups followed clinical practices for 8 months. Control group performed a public exposition of a clinical case about professional ethics. By contrast, an 8-month blended-learning programme regarding professional ethics was worked out for experimental group. An online syllabus and online activities were elaborated, while face-to-face active participation techniques were performed to discuss ethical issues. Students' attitudes, knowledge and opinions towards learning professional ethics were assessed. Ethical considerations: The study was approved by the University Ethic Committee of Human Research and followed the ethical principles according to the Declaration of Helsinki. After the programme, attitudes and knowledge towards learning professional ethics of experimental group students significantly improved, while no differences were observed in control group. Moreover, opinions reported an adequate extension of themes and temporization, importance of clinical practices and interest of topics. Case study method and role playing were considered as the most helpful techniques. The blended-learning programme proposed, based on professional ethics and related to clinical practices, improves physiotherapy students' attitudes, knowledge and opinions towards learning professional ethics.

Psychological Determinants of Consumer Acceptance of Personalised Nutrition in 9 European Countries

PubMed Central

Poínhos, Rui; van der Lans, Ivo A.; Rankin, Audrey; Fischer, Arnout R. H.; Bunting, Brendan; Kuznesof, Sharron; Stewart-Knox, Barbara; Frewer, Lynn J.

2014-01-01

Objective To develop a model of the psychological factors which predict people’s intention to adopt personalised nutrition. Potential determinants of adoption included perceived risk and benefit, perceived self-efficacy, internal locus of control and health commitment. Methods A questionnaire, developed from exploratory study data and the existing theoretical literature, and including validated psychological scales was administered to N = 9381 participants from 9 European countries (Germany, Greece, Ireland, Poland, Portugal, Spain, the Netherlands, the UK, and Norway). Results Structural equation modelling indicated that the greater participants’ perceived benefits to be associated with personalised nutrition, the more positive their attitudes were towards personalised nutrition, and the greater their intention to adopt it. Higher levels of nutrition self-efficacy were related to more positive attitudes towards, and a greater expressed intention to adopt, personalised nutrition. Other constructs positively impacting attitudes towards personalised nutrition included more positive perceptions of the efficacy of regulatory control to protect consumers (e.g. in relation to personal data protection), higher self-reported internal health locus of control, and health commitment. Although higher perceived risk had a negative relationship with attitude and an inverse relationship with perceived benefit, its effects on attitude and intention to adopt personalised nutrition was less influential than perceived benefit. The model was stable across the different European countries, suggesting that psychological factors determining adoption of personalised nutrition have generic applicability across different European countries. Conclusion The results suggest that transparent provision of information about potential benefits, and protection of consumers’ personal data is important for adoption, delivery of public health benefits, and commercialisation of personalised nutrition. PMID:25334009

Control of aedes vectors of dengue in three provinces of Vietnam by use of Mesocyclops (Copepoda) and community-based methods validated by entomologic, clinical, and serological surveillance.

PubMed

Kay, Brian H; Nam, Vu Sinh; Tien, Tran Van; Yen, Nguyen Thi; Phong, Tran Vu; Diep, Vu Thi Bich; Ninh, Truong Uyen; Bektas, Ahmet; Aaskov, John G

2002-01-01

We describe remarkable success in controlling dengue vectors, Aedes aegypti (L.) and Aedes albopictus (Skuse), in 6 communes with 11,675 households and 49,647 people in the northern provinces of Haiphong, Hung Yen, and Nam Dinh in Vietnam. The communes were selected for high-frequency use of large outdoor concrete tanks and wells. These were found to be the source of 49.6-98.4% of Ae. aegypti larvae, which were amenable to treatment with local Mesocyclops, mainly M. woutersi Van der Velde, M. aspericornis (Daday) and M. thermocyclopoides Harada. Knowledge, attitude, and practice surveys were performed to determine whether the communities viewed dengue and dengue hemorrhagic fever as a serious health threat; to determine their knowledge of the etiology, attitudes, and practices regarding control methods including Mesocyclops; and to determine their receptivity to various information methods. On the basis of the knowledge, attitude, and practice data, the community-based dengue control program comprised a system of local leaders, health volunteer teachers, and schoolchildren, supported by health professionals. Recycling of discards for economic gain was enhanced, where appropriate, and this, plus 37 clean-up campaigns, removed small containers unsuitable for Mesocyclops treatment. A previously successful eradication at Phan Boi village (Hung Yen province) was extended to 7 other villages forming Di Su commune (1,750 households) in the current study. Complete control was also achieved in Nghia Hiep (Hung Yen province) and in Xuan Phong (Nam Dinh province); control efficacy was > or = 99.7% in the other 3 communes (Lac Vien in Haiphong, Nghia Dong, and Xuan Kien in Nam Dinh). Although tanks and wells were the key container types of Ae. aegypti productivity, discarded materials were the source of 51% of the standing crop of Ae. albopictus. Aedes albopictus larvae were eliminated from the 3 Nam Dinh communes, and 86-98% control was achieved in the other 3 communes. Variable dengue attack rates made the clinical and serological comparison of control and untreated communes problematic, but these data indicate that clinical surveillance by itself is inadequate to monitor dengue transmission.

Attitude stabilization of a rigid spacecraft using two momentum wheel actuators

NASA Technical Reports Server (NTRS)

Krishnan, Hariharan; Mcclamroch, N. Harris; Reyhanoglu, Mahmut

1993-01-01

It is well known that three momentum wheel actuators can be used to control the attitude of a rigid spacecraft and that arbitrary reorientation maneuvers of the spacecraft can be accomplished using smooth feedback. If failure of one of the momentum wheel actuators occurs, it is demonstrated that two momentum wheel actuators can be used to control the attitude of a rigid spacecraft and that arbitrary reorientation maneuvers of the spacecraft can be accomplished. Although the complete spacecraft equations are not controllable, the spacecraft equations are small time locally controllable in a reduced nonlinear sense. The reduced spacecraft dynamics cannot be asymptotically stabilized to any equilibrium attitude using a time-variant continuous feedback control law, but discontinuous feedback control strategies are constructed which stabilize any equilibrium attitude of the spacecraft in finite time. Consequently, reorientation of the spacecraft can be accomplished using discontinuous feedback control.

Categorization and Prediction of Crimes of Passion Based on Attitudes Toward Violence.

PubMed

Guan, Muzhen; Li, Xiaojing; Xiao, Wei; Miao, Danmin; Liu, Xufeng

2017-11-01

The present study explored implicit and explicit attitudes toward violence in crimes of passion. Criminals ( n = 96) who had perpetrated crimes of passion and students ( n = 100) participated in this study. Explicit attitudes toward violence were evaluated using the Abnormal Personality Risk Inventory (APRI), and implicit attitude toward violence was evaluated using the Implicit Association Test (IAT). Results indicated that APRI scores of the perpetrators were significantly higher than that of the control group ( p < .05), suggesting that explicit attitudes toward violence could discriminate between the criminals and the control group. There was a significant IAT effect demonstrating a negative implicit attitude toward violence in both the control group and in the criminals ( n = 68); whereas there was a significant IAT effect manifesting a positive implicit attitude toward violence in the criminals ( n = 16) only. These results suggest that combining explicit and implicit attitudes could provide an empirical classification of crimes of passion.

Finite-Time Attitude Tracking Control for Spacecraft Using Terminal Sliding Mode and Chebyshev Neural Network.

PubMed

An-Min Zou; Kumar, K D; Zeng-Guang Hou; Xi Liu

2011-08-01

A finite-time attitude tracking control scheme is proposed for spacecraft using terminal sliding mode and Chebyshev neural network (NN) (CNN). The four-parameter representations (quaternion) are used to describe the spacecraft attitude for global representation without singularities. The attitude state (i.e., attitude and velocity) error dynamics is transformed to a double integrator dynamics with a constraint on the spacecraft attitude. With consideration of this constraint, a novel terminal sliding manifold is proposed for the spacecraft. In order to guarantee that the output of the NN used in the controller is bounded by the corresponding bound of the approximated unknown function, a switch function is applied to generate a switching between the adaptive NN control and the robust controller. Meanwhile, a CNN, whose basis functions are implemented using only desired signals, is introduced to approximate the desired nonlinear function and bounded external disturbances online, and the robust term based on the hyperbolic tangent function is applied to counteract NN approximation errors in the adaptive neural control scheme. Most importantly, the finite-time stability in both the reaching phase and the sliding phase can be guaranteed by a Lyapunov-based approach. Finally, numerical simulations on the attitude tracking control of spacecraft in the presence of an unknown mass moment of inertia matrix, bounded external disturbances, and control input constraints are presented to demonstrate the performance of the proposed controller.

Attitude towards gender roles and violence against women and girls (VAWG): baseline findings from an RCT of 1752 youths in Pakistan

PubMed Central

Saeed Ali, Tazeen; Karmaliani, Rozina; Mcfarlane, Judith; Khuwaja, Hussain M. A.; Somani, Yasmeen; Chirwa, Esnat D.; Jewkes, Rachel

2017-01-01

ABSTRACT Background: Violence against women is driven by gender norms that normalize and justify gender inequality and violence. Gender norms are substantially shaped during adolescence. Programs offered through schools offer an opportunity to influence gender attitudes toward gender equity if we understand these to be partly shaped by peers and the school environment. Objective: We present an analysis of the baseline research conducted for a randomized controlled trial with 1752 grade 6 boys and girls and their attitudes toward gender roles, VAWG, and associated factors. Methods: We used baseline data from a  cluster randomised control study. Interviews were conducted in 40 public schools in Hyderabad, with 25–65 children per school. Questions were asked about attitudes toward gender roles, peer-to-peer perpetration, and victimization experiences, and family life, including father- or in-law-to- mother violence and food security. Multiple regression models were built of factors associated with gender attitudes for boys and girls. Results: Our result have shown youth attitudes endorsing patriarchal gender beliefs were higher for boys, compared to girls. The multiple regression model showed that for boys, patriarchal gender attitudes were positively associated with hunger, depression, being promised already in marriage, and being a victim and/or perpetrator of peer violence. For girls gender attitudes were associated with hunger, experiencing corporal punishment at home, and being a perpetrator (for some, and victim) of peer violence. Conclusion: Youth patriarchal attitudes are closely related to their experience of violence at school and for girl’s physical punishment, at home and for boys being promised in early marriage. We suggest that these variables are indicators of gender norms among peers and in the family. The significance of peer norms is that it provides the possibility that school-based interventions which work with school peers have the potential to positively impact youth patriarchal gender attitudes and foster attitudes of gender equality and respect, and potentially to decrease youth victimization and perpetration. PMID:28758882

The attitude inversion method of geostationary satellites based on unscented particle filter

NASA Astrophysics Data System (ADS)

Du, Xiaoping; Wang, Yang; Hu, Heng; Gou, Ruixin; Liu, Hao

2018-04-01

The attitude information of geostationary satellites is difficult to be obtained since they are presented in non-resolved images on the ground observation equipment in space object surveillance. In this paper, an attitude inversion method for geostationary satellite based on Unscented Particle Filter (UPF) and ground photometric data is presented. The inversion algorithm based on UPF is proposed aiming at the strong non-linear feature in the photometric data inversion for satellite attitude, which combines the advantage of Unscented Kalman Filter (UKF) and Particle Filter (PF). This update method improves the particle selection based on the idea of UKF to redesign the importance density function. Moreover, it uses the RMS-UKF to partially correct the prediction covariance matrix, which improves the applicability of the attitude inversion method in view of UKF and the particle degradation and dilution of the attitude inversion method based on PF. This paper describes the main principles and steps of algorithm in detail, correctness, accuracy, stability and applicability of the method are verified by simulation experiment and scaling experiment in the end. The results show that the proposed method can effectively solve the problem of particle degradation and depletion in the attitude inversion method on account of PF, and the problem that UKF is not suitable for the strong non-linear attitude inversion. However, the inversion accuracy is obviously superior to UKF and PF, in addition, in the case of the inversion with large attitude error that can inverse the attitude with small particles and high precision.

Hamiltonian Dynamics of Spider-Type Multirotor Rigid Bodies Systems

NASA Astrophysics Data System (ADS)

Doroshin, Anton V.

2010-03-01

This paper sets out to develop a spider-type multiple-rotor system which can be used for attitude control of spacecraft. The multirotor system contains a large number of rotor-equipped rays, so it was called a ``Spider-type System,'' also it can be called ``Rotary Hedgehog.'' These systems allow using spinups and captures of conjugate rotors to perform compound attitude motion of spacecraft. The paper describes a new method of spacecraft attitude reorientation and new mathematical model of motion in Hamilton form. Hamiltonian dynamics of the system is investigated with the help of Andoyer-Deprit canonical variables. These variables allow obtaining exact solution for hetero- and homoclinic orbits in phase space of the system motion, which are very important for qualitative analysis.

The Impact of a Modified Moore Method on Efficacy and Performance in Precalculus

ERIC Educational Resources Information Center

Cooper, Thomas E.; Bailey, Brad; Briggs, Karen

2012-01-01

In this study, one section of undergraduate Precalculus was taught using a modified Moore method, a student centered inquiry-based approach, and two control sections were taught in a traditional lecture format. A survey of attitudes, beliefs, and efficacy toward mathematics and Precalculus was administered at the beginning and end of the semester…

Normal Science and the Paranormal: The Effect of a Scientific Method Course on Students' Beliefs.

ERIC Educational Resources Information Center

Morier, Dean; Keeports, David

1994-01-01

A study investigated the effects of an interdisciplinary course on the scientific method on the attitudes of 34 college students toward the paranormal. Results indicated that the course substantially reduced belief in the paranormal, relative to a control group. Student beliefs in their own paranormal powers, however, did not change. (Author/MSE)

Eating on impulse: Implicit attitudes, self-regulatory resources, and trait self-control as determinants of food consumption.

PubMed

Wang, Yan; Wang, Lei; Cui, Xianghua; Fang, Yuan; Chen, Qianqiu; Wang, Ya; Qiang, Yao

2015-12-01

Self-regulatory resources and trait self-control have been found to moderate the impulse-behavior relationship. The current study investigated whether the interaction of self-regulatory resources and trait self-control moderates the association between implicit attitudes and food consumption. One hundred twenty female participants were randomly assigned to either a depletion condition in which their self-regulatory resources were reduced or a no-depletion condition. Participants' implicit attitudes for chocolate were measured with the Single Category Implicit Association Test and self-report measures of trait self-control were collected. The dependent variable was chocolate consumption in an ostensible taste and rate task. Implicit attitudes predicted chocolate consumption in depleted participants but not in non-depleted participants. However, this predictive power of implicit attitudes on eating in depleted condition disappeared in participants with high trait self-control. Thus, trait self-control and self-regulatory resources interact to moderate the prediction of implicit attitude on eating behavior. Results suggest that high trait self-control buffers the effect of self-regulatory depletion on impulsive eating. Copyright © 2015 Elsevier Ltd. All rights reserved.

The accuracy of dynamic attitude propagation

NASA Technical Reports Server (NTRS)

Harvie, E.; Chu, D.; Woodard, M.

1990-01-01

Propagating attitude by integrating Euler's equation for rigid body motion has long been suggested for the Earth Radiation Budget Satellite (ERBS) but until now has not been implemented. Because of limited Sun visibility, propagation is necessary for yaw determination. With the deterioration of the gyros, dynamic propagation has become more attractive. Angular rates are derived from integrating Euler's equation with a stepsize of 1 second, using torques computed from telemetered control system data. The environmental torque model was quite basic. It included gravity gradient and unshadowed aerodynamic torques. Knowledge of control torques is critical to the accuracy of dynamic modeling. Due to their coarseness and sparsity, control actuator telemetry were smoothed before integration. The dynamic model was incorporated into existing ERBS attitude determination software. Modeled rates were then used for attitude propagation in the standard ERBS fine-attitude algorithm. In spite of the simplicity of the approach, the dynamically propagated attitude matched the attitude propagated with good gyros well for roll and yaw but diverged up to 3 degrees for pitch because of the very low resolution in pitch momentum wheel telemetry. When control anomalies significantly perturb the nominal attitude, the effect of telemetry granularity is reduced and the dynamically propagated attitudes are accurate on all three axes.

Mood state dependency of dysfunctional attitudes in bipolar affective disorder.

PubMed

Babakhani, Anet; Startup, Mike

2012-01-01

Studies of cognitive styles among euthymic people with bipolar affective disorder (BAD) without use of mood induction techniques to access those cognitive styles give misleading impressions of normality of those cognitions. The aim of this study was to assess dysfunctional attitudes of participants with BAD, and control participants with no previous psychiatric histories, after mood inductions. Sad and happy moods were induced within 49 BAD and 37 controls. Dysfunctional attitudes were measured following mood inductions using the Dysfunctional Attitude Scale-short form (DAS-24), which has three subscales of achievement, interpersonal, and goal attainment. It was hypothesised that within BAD the sad mood induction would help in accessing dysfunctional attitudes in all three domains relative to the happy mood induction. This was supported. It was also hypothesised that the mood inductions would not affect dysfunctional attitudes within controls. This was supported. When diagnosis was entered as a between group variable, achievement dysfunctional attitudes were significantly higher in BAD compared to controls after a happy induction. Both sad and happy moods provoked higher levels of dysfunctional attitudes within BAD. Euphoria may be related to elevated achievement dysfunctional attitudes, raising risk for mania.

The impact of eLearning on health professional educators’ attitudes to information and communication technology

PubMed Central

Neville, Victoria; Lam, Mary; Gordon, Christopher J

2015-01-01

Background The use of information and communication technology (ICT) in health professional education is increasing rapidly. Health professional educators need to be responsive to health professionals’ information and communication technological needs; however, there is a paucity of information about educators’ attitudes to, and capabilities with, ICT. Methods Fifty-two health professional educators, enrolled in health professional education postgraduate studies, participated in an online subject with specific eLearning components requiring the use of ICT. They completed a pre- and postquestionnaire pertaining to ICT attitudes, confidence, and usage. Results Participants reported significant increases in overall ICT confidence during the subject despite it being high at baseline (mean: 7.0 out of 10; P=0.02). Even with increased ICT confidence, there were decreases in the participants’ sense of ICT control when related to health professional education (P=0.002); whereas, the amount of time participants engaged with ICT devices was negatively correlated with the sense of ICT control (P=0.002). The effect of age and health discipline on ICT attitudes and confidence was not significant (P>0.05). Conclusion This study reports that health professional educators have perceptual deficits toward ICT. The impact of eLearning increased confidence in ICT but caused a reduction in participants’ sense of control of ICT. Health professional educators require more ICT training and support to facilitate better ICT integration in health professional education settings. PMID:25678796

Attitude Control System Design for the Solar Dynamics Observatory

NASA Technical Reports Server (NTRS)

Starin, Scott R.; Bourkland, Kristin L.; Kuo-Chia, Liu; Mason, Paul A. C.; Vess, Melissa F.; Andrews, Stephen F.; Morgenstern, Wendy M.

2005-01-01

The Solar Dynamics Observatory mission, part of the Living With a Star program, will place a geosynchronous satellite in orbit to observe the Sun and relay data to a dedicated ground station at all times. SDO remains Sun- pointing throughout most of its mission for the instruments to take measurements of the Sun. The SDO attitude control system is a single-fault tolerant design. Its fully redundant attitude sensor complement includes 16 coarse Sun sensors, a digital Sun sensor, 3 two-axis inertial reference units, 2 star trackers, and 4 guide telescopes. Attitude actuation is performed using 4 reaction wheels and 8 thrusters, and a single main engine nominally provides velocity-change thrust. The attitude control software has five nominal control modes-3 wheel-based modes and 2 thruster-based modes. A wheel-based Safehold running in the attitude control electronics box improves the robustness of the system as a whole. All six modes are designed on the same basic proportional-integral-derivative attitude error structure, with more robust modes setting their integral gains to zero. The paper details the mode designs and their uses.

Attributions and Attitudes of Mothers and Fathers in Italy

PubMed Central

Bombi, Anna Silvia; Pastorelli, Concetta; Bacchini, Dario; Di Giunta, Laura; Miranda, Maria C.; Zelli, Arnaldo

2011-01-01

SYNOPSIS Objective The present study examined mean level similarities and differences as well as correlations between mothers’ and fathers’ attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. Design Interviews were conducted with both mothers and fathers in 177 Italian families from Rome and Naples. Results Fathers’ attributions reflected higher perceived control over failure than did mothers’ attributions, whereas mothers reported attitudes that were more progressive than did fathers. Only the difference in progressive attitudes remained significant after controlling for parents’ age, education, and possible social desirability bias. Site differences emerged for four of the seven attributions and attitudes examined; three remained significant after controlling for parents’ age, education, and possible social desirability bias. Medium effect sizes were found for concordance between parents in the same family for authoritarian attitudes and modernity of attitudes after controlling for parents’ age, education, and possible social desirability bias. Conclusions This work elucidates ways that parent gender and cultural context relate to attributions regarding parents’ success and failure in caregiving situations and to progressive versus authoritarian parenting attitudes. PMID:21927586

Attributions and Attitudes of Mothers and Fathers in Italy.

PubMed

Bombi, Anna Silvia; Pastorelli, Concetta; Bacchini, Dario; Di Giunta, Laura; Miranda, Maria C; Zelli, Arnaldo

2011-07-01

OBJECTIVE: The present study examined mean level similarities and differences as well as correlations between mothers' and fathers' attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. DESIGN: Interviews were conducted with both mothers and fathers in 177 Italian families from Rome and Naples. RESULTS: Fathers' attributions reflected higher perceived control over failure than did mothers' attributions, whereas mothers reported attitudes that were more progressive than did fathers. Only the difference in progressive attitudes remained significant after controlling for parents' age, education, and possible social desirability bias. Site differences emerged for four of the seven attributions and attitudes examined; three remained significant after controlling for parents' age, education, and possible social desirability bias. Medium effect sizes were found for concordance between parents in the same family for authoritarian attitudes and modernity of attitudes after controlling for parents' age, education, and possible social desirability bias. CONCLUSIONS: This work elucidates ways that parent gender and cultural context relate to attributions regarding parents' success and failure in caregiving situations and to progressive versus authoritarian parenting attitudes.

Effect of Educational Intervention on the Fruit and Vegetables Consumption among the Students: Applying Theory of Planned Behavior.

PubMed

Taghdisi, Mohammad Hossein; Babazadeh, Towhid; Moradi, Fatemeh; Shariat, Fariba

2016-01-01

The importance of consuming fruits and vegetables (F&V) in prevention of chronic diseases is known. Childhood play an important role in formation of healthy eating habits. The purpose of this study was to examine the effect of education, with application of the theory of planned behavior, on improvement of F&V consumption. In this quasi-experimental study, 184 fourth, fifth, and sixth-grade students participated were enrolled from Jan 2013 to Jun 2014. The samples were selected from 6 schools in Chalderan County, West Azerbaijan, Iran through cluster random sampling method. Two out of 6 schools were randomly selected and each was employed in either experimental or control group. The data collection instruments included a researcher-made questionnaire and a 24-h F&V recall. Data were collected after verification of the reliability and validity of the questionnaire. Before the intervention, no significant difference was observed between the intervention and control group regarding attitude, subjective norms, perceived behavioral control, behavioral intention and fruits and vegetables consumption (P>0.05). However, after the educational intervention, the mean scores of attitude, subjective norms, perceived behavioral control, behavioral intention variables and fruits and vegetables were significantly higher in the intervention group when compared to the control group(P<0.05). Increased behavioral intention, attitude, subjective norms, and perceived behavioral control can promote F&V consumption among the students.

Thrust vector control of upper stage with a gimbaled thruster during orbit transfer

NASA Astrophysics Data System (ADS)

Wang, Zhaohui; Jia, Yinghong; Jin, Lei; Duan, Jiajia

2016-10-01

In launching Multi-Satellite with One-Vehicle, the main thruster provided by the upper stage is mounted on a two-axis gimbal. During orbit transfer, the thrust vector of this gimbaled thruster (GT) should theoretically pass through the mass center of the upper stage and align with the command direction to provide orbit transfer impetus. However, it is hard to be implemented from the viewpoint of the engineering mission. The deviations of the thrust vector from the command direction would result in large velocity errors. Moreover, the deviations of the thrust vector from the upper stage mass center would produce large disturbance torques. This paper discusses the thrust vector control (TVC) of the upper stage during its orbit transfer. Firstly, the accurate nonlinear coupled kinematic and dynamic equations of the upper stage body, the two-axis gimbal and the GT are derived by taking the upper stage as a multi-body system. Then, a thrust vector control system consisting of the special attitude control of the upper stage and the gimbal rotation of the gimbaled thruster is proposed. The special attitude control defined by the desired attitude that draws the thrust vector to align with the command direction when the gimbal control makes the thrust vector passes through the upper stage mass center. Finally, the validity of the proposed method is verified through numerical simulations.

Docking Offset Between the Space Shuttle and the International Space Station and Resulting Impacts to the Transfer of Attitude Reference and Control

NASA Technical Reports Server (NTRS)

Helms, W. Jason; Pohlkamp, Kara M.

2011-01-01

The Space Shuttle does not dock at an exact 90 degrees to the International Space Station (ISS) x-body axis. This offset from 90 degrees, along with error sources within their respective attitude knowledge, causes the two vehicles to never completely agree on their attitude, even though they operate as a single, mated stack while docked. The docking offset can be measured in flight when both vehicles have good attitude reference and is a critical component in calculations to transfer attitude reference from one vehicle to another. This paper will describe how the docking offset and attitude reference errors between both vehicles are measured and how this information would be used to recover Shuttle attitude reference from ISS in the event of multiple failures. During STS-117, ISS on-board Guidance, Navigation and Control (GNC) computers began having problems and after several continuous restarts, the systems failed. The failure took the ability for ISS to maintain attitude knowledge. This paper will also demonstrate how with knowledge of the docking offset, the contingency procedure to recover Shuttle attitude reference from ISS was reversed in order to provide ISS an attitude reference from Shuttle. Finally, this paper will show how knowledge of the docking offset can be used to speed up attitude control handovers from Shuttle to ISS momentum management. By taking into account the docking offset, Shuttle can be commanded to hold a more precise attitude which better agrees with the ISS commanded attitude such that start up transients with the ISS momentum management controllers are reduced. By reducing start-up transients, attitude control can be transferred from Shuttle to ISS without the use of ISS thrusters saving precious on-board propellant, crew time and minimizing loads placed upon the mated stack.

Attitude control fault protection - The Voyager experience

NASA Technical Reports Server (NTRS)

Litty, E. C.

1980-01-01

The length of the Voyager mission and the communication delay caused by the distances involved made fault protection a necessary part of the Voyager Attitude and Articulation Control Subsystem (AACS) design. An overview of the Voyager attitude control fault protection is given and flight experiences relating to fault protection are provided.

Dynamic modeling and ascent flight control of Ares-I Crew Launch Vehicle

NASA Astrophysics Data System (ADS)

Du, Wei

This research focuses on dynamic modeling and ascent flight control of large flexible launch vehicles such as the Ares-I Crew Launch Vehicle (CLV). A complete set of six-degrees-of-freedom dynamic models of the Ares-I, incorporating its propulsion, aerodynamics, guidance and control, and structural flexibility, is developed. NASA's Ares-I reference model and the SAVANT Simulink-based program are utilized to develop a Matlab-based simulation and linearization tool for an independent validation of the performance and stability of the ascent flight control system of large flexible launch vehicles. A linearized state-space model as well as a non-minimum-phase transfer function model (which is typical for flexible vehicles with non-collocated actuators and sensors) are validated for ascent flight control design and analysis. This research also investigates fundamental principles of flight control analysis and design for launch vehicles, in particular the classical "drift-minimum" and "load-minimum" control principles. It is shown that an additional feedback of angle-of-attack can significantly improve overall performance and stability, especially in the presence of unexpected large wind disturbances. For a typical "non-collocated actuator and sensor" control problem for large flexible launch vehicles, non-minimum-phase filtering of "unstably interacting" bending modes is also shown to be effective. The uncertainty model of a flexible launch vehicle is derived. The robust stability of an ascent flight control system design, which directly controls the inertial attitude-error quaternion and also employs the non-minimum-phase filters, is verified by the framework of structured singular value (mu) analysis. Furthermore, nonlinear coupled dynamic simulation results are presented for a reference model of the Ares-I CLV as another validation of the feasibility of the ascent flight control system design. Another important issue for a single main engine launch vehicle is stability under mal-function of the roll control system. The roll motion of the Ares-I Crew Launch Vehicle under nominal flight conditions is actively stabilized by its roll control system employing thrusters. This dissertation describes the ascent flight control design problem of Ares-I in the event of disabled or failed roll control. A simple pitch/yaw control logic is developed for such a technically challenging problem by exploiting the inherent versatility of a quaternion-based attitude control system. The proposed scheme requires only the desired inertial attitude quaternion to be re-computed using the actual uncontrolled roll angle information to achieve an ascent flight trajectory identical to the nominal flight case with active roll control. Another approach that utilizes a simple adjustment of the proportional-derivative gains of the quaternion-based flight control system without active roll control is also presented. This approach doesn't require the re-computation of desired inertial attitude quaternion. A linear stability criterion is developed for proper adjustments of attitude and rate gains. The linear stability analysis results are validated by nonlinear simulations of the ascent flight phase. However, the first approach, requiring a simple modification of the desired attitude quaternion, is recommended for the Ares-I as well as other launch vehicles in the event of no active roll control. Finally, the method derived to stabilize a large flexible launch vehicle in the event of uncontrolled roll drift is generalized as a modified attitude quaternion feedback law. It is used to stabilize an axisymmetric rigid body by two independent control torques.

Navigation Algorithms for the SeaWiFS Mission

NASA Technical Reports Server (NTRS)

Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Patt, Frederick S.; McClain, Charles R. (Technical Monitor)

2002-01-01

The navigation algorithms for the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) were designed to meet the requirement of 1-pixel accuracy-a standard deviation (sigma) of 2. The objective has been to extract the best possible accuracy from the spacecraft telemetry and avoid the need for costly manual renavigation or geometric rectification. The requirement is addressed by postprocessing of both the Global Positioning System (GPS) receiver and Attitude Control System (ACS) data in the spacecraft telemetry stream. The navigation algorithms described are separated into four areas: orbit processing, attitude sensor processing, attitude determination, and final navigation processing. There has been substantial modification during the mission of the attitude determination and attitude sensor processing algorithms. For the former, the basic approach was completely changed during the first year of the mission, from a single-frame deterministic method to a Kalman smoother. This was done for several reasons: a) to improve the overall accuracy of the attitude determination, particularly near the sub-solar point; b) to reduce discontinuities; c) to support the single-ACS-string spacecraft operation that was started after the first mission year, which causes gaps in attitude sensor coverage; and d) to handle data quality problems (which became evident after launch) in the direct-broadcast data. The changes to the attitude sensor processing algorithms primarily involved the development of a model for the Earth horizon height, also needed for single-string operation; the incorporation of improved sensor calibration data; and improved data quality checking and smoothing to handle the data quality issues. The attitude sensor alignments have also been revised multiple times, generally in conjunction with the other changes. The orbit and final navigation processing algorithms have remained largely unchanged during the mission, aside from refinements to data quality checking. Although further improvements are certainly possible, future evolution of the algorithms is expected to be limited to refinements of the methods presented here, and no substantial changes are anticipated.

LQG/LTR optimal attitude control of small flexible spacecraft using free-free boundary conditions

NASA Astrophysics Data System (ADS)

Fulton, Joseph M.

Due to the volume and power limitations of a small satellite, careful consideration must be taken while designing an attitude control system for 3-axis stabilization. Placing redundancy in the system proves difficult and utilizing power hungry, high accuracy, active actuators is not a viable option. Thus, it is customary to find dependable, passive actuators used in conjunction with small scale active control components. This document describes the application of Elastic Memory Composite materials in the construction of a flexible spacecraft appendage, such as a gravity gradient boom. Assumed modes methods are used with Finite Element Modeling information to obtain the equations of motion for the system while assuming free-free boundary conditions. A discussion is provided to illustrate how cantilever mode shapes are not always the best assumption when modeling small flexible spacecraft. A key point of interest is first resonant modes may be needed in the system design plant in spite of these modes being greater than one order of magnitude in frequency when compared to the crossover frequency of the controller. LQG/LTR optimal control techniques are implemented to compute attitude control gains while controller robustness considerations determine appropriate reduced order controllers and which flexible modes to include in the design model. Key satellite designer concerns in the areas of computer processor sizing, material uncertainty impacts on the system model, and system performance variations resulting from appendage length modifications are addressed.

Effect of an institutional development plan for user participation on professionals' knowledge, practice, and attitudes. A controlled study

PubMed Central

2011-01-01

Background Governments in several countries attempt to strengthen user participation through instructing health care organisations to plan and implement activities such as user representation in administrational boards, improved information to users, and more individual user participation in clinical work. The professionals are central in implementing initiatives to enhance user participation in organisations, but no controlled studies have been conducted on the effect on professionals from implementing institutional development plans. The objective was to investigate whether implementing a development plan intending to enhance user participation in a mental health hospital had any effect on the professionals' knowledge, practice, or attitudes towards user participation. Methods This was a non-randomized controlled study including professionals from three mental health hospitals in Central Norway. A development plan intended to enhance user participation was implemented in one of the hospitals as a part of a larger re-organizational process. The plan included i.e. establishing a patient education centre and a user office, purchasing of user expertise, appointing contact professionals for next of kin, and improving of the centre's information and the professional culture. The professionals at the intervention hospital thus constituted the intervention group, while the professionals at two other hospitals participated as control group. All professionals were invited to answer the Consumer Participation Questionnaire (CPQ) and additional questions, focusing on knowledge, practice, and attitudes towards user participation, two times with a 16 months interval. Results A total of 438 professionals participated (55% response rate). Comparing the changes in the intervention group with the changes in the control group revealed no statistically significant differences at a 0.05 level. The implementation of the development plan thus had no measurable effect on the professionals' knowledge, practice, or attitudes at the intervention hospital, compared to the control hospitals. Conclusion This is the first controlled study on the effect on professionals from implementing a development plan to enhance user participation in a mental health hospital. The plan had no effect on professionals' knowledge, practice, or attitudes. This can be due to the quality of the development plan, the implementation process, and/or the suitability of the outcome measures. PMID:22047466

Thrust vector control algorithm design for the Cassini spacecraft

NASA Technical Reports Server (NTRS)

Enright, Paul J.

1993-01-01

This paper describes a preliminary design of the thrust vector control algorithm for the interplanetary spacecraft, Cassini. Topics of discussion include flight software architecture, modeling of sensors, actuators, and vehicle dynamics, and controller design and analysis via classical methods. Special attention is paid to potential interactions with structural flexibilities and propellant dynamics. Controller performance is evaluated in a simulation environment built around a multi-body dynamics model, which contains nonlinear models of the relevant hardware and preliminary versions of supporting attitude determination and control functions.

Space construction base control system

NASA Technical Reports Server (NTRS)

1978-01-01

Aspects of an attitude control system were studied and developed for a large space base that is structurally flexible and whose mass properties change rather dramatically during its orbital lifetime. Topics of discussion include the following: (1) space base orbital pointing and maneuvering; (2) angular momentum sizing of actuators; (3) momentum desaturation selection and sizing; (4) multilevel control technique applied to configuration one; (5) one-dimensional model simulation; (6) N-body discrete coordinate simulation; (7) structural analysis math model formulation; and (8) discussion of control problems and control methods.

High-precision relative position and attitude measurement for on-orbit maintenance of spacecraft

NASA Astrophysics Data System (ADS)

Zhu, Bing; Chen, Feng; Li, Dongdong; Wang, Ying

2018-02-01

In order to realize long-term on-orbit running of satellites, space stations, etc spacecrafts, in addition to the long life design of devices, The life of the spacecraft can also be extended by the on-orbit servicing and maintenance. Therefore, it is necessary to keep precise and detailed maintenance of key components. In this paper, a high-precision relative position and attitude measurement method used in the maintenance of key components is given. This method mainly considers the design of the passive cooperative marker, light-emitting device and high resolution camera in the presence of spatial stray light and noise. By using a series of algorithms, such as background elimination, feature extraction, position and attitude calculation, and so on, the high precision relative pose parameters as the input to the control system between key operation parts and maintenance equipment are obtained. The simulation results show that the algorithm is accurate and effective, satisfying the requirements of the precision operation technique.

Determination of poles and zeros of transfer functions for flexible spacecraft attitude control

NASA Technical Reports Server (NTRS)

Ohkami, Y.; Likins, P. W.

1976-01-01

The transfer function matrix is obtained for a three-input and three-output model of minimum sensors and actuators for the attitude control system of flexible spacecraft, and a method is described for determining the poles and zeros of this transfer function. Three cases are considered: (1) the actuators and the sensors are all attached to the primary body, (2) the actuators are on the primary body and the sensors are on the sub-body, and (3) the actuators are on the sub-body and the sensors are on the primary body. The zero-determination problem is shown to reduce to eigenvalue calculations of a matrix which is constructed from the inertial and modal matrices in a simple fashion.

The effect of comprehensive sexual education program on sexual health knowledge and sexual attitude among college students in Southwest China.

PubMed

Chi, Xinli; Hawk, Skyler T; Winter, Sam; Meeus, Wim

2015-03-01

The purpose of this study was to evaluate whether a comprehensive sexual education program for college students in Southwest China (a) improved sexual health knowledge in reproduction, contraception, condom use, sexually transmitted diseases, and HIV; (b) increased accepting attitudes toward lesbian, gay, bisexual, and transsexual individuals; and (c) altered participants' attitudes toward premarital sex and monogamy. The program used diverse teaching methods, providing 6 sessions over a period of 9 weeks about sexual health knowledge and sexual attitudes to college students (age 18-26 years) in Southwest China. Sexual health knowledge and sexual attitudes of 80 comprehensive sexual education class students (education group) and 92 general mental health education class students (control group) were measured at baseline, the end of course (posttest), and 3 weeks after the end of course (follow-up). There were significant effects of the program on (a) sexual health knowledge, including reproductive health, contraception, condom use, and HIV/AIDS and (b) positive attitudes toward sexual minorities, although these changes may require further reinforcement. In contrast, the program did not alter students' attitudes about premarital sex or monogamy. The results are discussed in terms of recommendations of sex education in China and future directions for research. © 2013 APJPH.

Ethical, Legal, and Practical Issues in the Control and Regulation of Suicide Promotion and Assistance over the Internet

ERIC Educational Resources Information Center

Mishara, Brian L.; Weisstub, David N.

2007-01-01

The promotion of suicide and description of suicide methods on the Internet have led to widespread concern that legal control is mandated. Apart from value concerns pertaining to attitudes about suicide, the guarantee of freedom of expression presents a serious challenge to the introduction of restrictive laws. Recent developments in Australia and…

The Efficacy of Three Learning Methods Collaborative, Context-Based Learning and Traditional, on Learning, Attitude and Behaviour of Undergraduate Nursing Students: Integrating Theory and Practice.

PubMed

Hasanpour-Dehkordi, Ali; Solati, Kamal

2016-04-01

Communication skills training, responsibility, respect, and self-awareness are important indexes of changing learning behaviours in modern approaches. The aim of this study was to investigate the efficacy of three learning approaches, collaborative, context-based learning (CBL), and traditional, on learning, attitude, and behaviour of undergraduate nursing students. This study was a clinical trial with pretest and post-test of control group. The participants were senior nursing students. The samples were randomly assigned to three groups; CBL, collaborative, and traditional. To gather data a standard questionnaire of students' behaviour and attitude was administered prior to and after the intervention. Also, the rate of learning was investigated by a researcher-developed questionnaire prior to and after the intervention in the three groups. In CBL and collaborative training groups, the mean score of behaviour and attitude increased after the intervention. But no significant association was obtained between the mean scores of behaviour and attitude prior to and after the intervention in the traditional group. However, the mean learning score increased significantly in the CBL, collaborative, and traditional groups after the study in comparison to before the study. Both CBL and collaborative approaches were useful in terms of increased respect, self-awareness, self-evaluation, communication skills and responsibility as well as increased motivation and learning score in comparison to traditional method.

On the generalization of attitude accessibility after repeated attitude expression

PubMed Central

Spruyt, Adriaan; Fazio, Russell H.; Hermans, Dirk

2016-01-01

Abstract The more accessible an attitude is, the stronger is its influence on information processing and behavior. Accessibility can be increased through attitude rehearsal, but it remains unknown whether attitude rehearsal also affects the accessibility of related attitudes. To investigate this hypothesis, participants in an experimental condition repeatedly expressed their attitudes towards exemplars of several semantic categories during an evaluative categorization task. Participants in a control condition performed a non‐evaluative task with the same exemplars and evaluated unrelated attitude objects. After a 30‐minute interval, participants in the experimental condition were faster than controls to evaluate not only the original exemplars but also novel exemplars of the same categories. This finding suggests that the effect of attitude rehearsal on accessibility generalizes to attitudes towards untrained but semantically related attitude objects. © 2016 The Authors. European Journal of Social Psychology published by John Wiley & Sons, Ltd. PMID:28701803

Overview of the Miniature Sensor Technology Integration (MSTI) spacecraft attitude control system

NASA Technical Reports Server (NTRS)

Mcewen, Rob

1994-01-01

Msti2 is a small, 164 kg (362 lb), 3-axis stabilized, low-Earth-orbiting satellite whose mission is missile booster tracking. The spacecraft is actuated by 3 reaction wheels and 12 hot gas thrusters. It carries enough fuel for a projected life of 6 months. The sensor complement consists of a Horizon Sensor, a Sun Sensor, low-rate gyros, and a high rate gyro for despin. The total pointing control error allocation is 6 mRad (.34 Deg), and this is while tracking a target on the Earth's surface. This paper describes the Attitude Control System (ACS) algorithms which include the following: attitude acquisition (despin, Sun and Earth acquisition), attitude determination, attitude control, and linear stability analysis.

Attitude analysis of the Earth Radiation Budget Satellite (ERBS) yaw turn anomaly

NASA Technical Reports Server (NTRS)

Kronenwetter, J.; Phenneger, M.; Weaver, William L.

1988-01-01

The July 2 Earth Radiation Budget Satellite (ERBS) hydrazine thruster-controlled yaw inversion maneuver resulted in a 2.1 deg/sec attitude spin. This mode continued for 150 minutes until the spacecraft was inertially despun using the hydrazine thrusters. The spacecraft remained in a low-rate Y-axis spin of .06 deg/sec for 3 hours until the B-DOT control mode was activated. After 5 hours in this mode, the spacecraft Y-axis was aligned to the orbit normal, and the spacecraft was commanded to the mission mode of attitude control. This work presents the experience of real-time attitude determination support following analysis using the playback telemetry tape recorded for 7 hours from the start of the attitude control anomaly.

Positive thinking elevates tolerance: Experimental effects of happiness on adolescents' attitudes toward asylum seekers.

PubMed

Tenenbaum, Harriet R; Capelos, Tereza; Lorimer, Jessica; Stocks, Thomas

2018-04-01

Inducing emotional reactions toward social groups can influence individuals' political tolerance. This study examines the influence of incidental fear and happiness on adolescents' tolerant attitudes and feelings toward young Muslim asylum seekers. In our experiment, 219 16- to 21-year-olds completed measures of prejudicial attitudes. After being induced to feel happiness, fear, or no emotion (control), participants reported their tolerant attitudes and feelings toward asylum-seeking young people. Participants assigned to the happiness condition demonstrated more tolerant attitudes toward asylum-seeking young people than did those assigned to the fear or control conditions. Participants in the control condition did not differ from participants in the fear condition. The participants in the happiness condition also had more positive feelings toward asylum-seeking young people than did participants in the control condition. The findings suggest that one way to increase positive attitudes toward asylum-seeking young people is to improve general emotional state.

Attributions and Attitudes of Mothers and Fathers in Sweden.

PubMed

Sorbring, Emma; Gurdal, Sevtap

2011-07-01

OBJECTIVE: The present study examined mean level similarities and differences as well as correlations between mothers' and fathers' attributions regarding successes and failures in caregiving situations and progressive versus authoritarian attitudes. DESIGN: Interviews were conducted with both mothers and fathers in 77 Swedish families. RESULTS: Fathers reported higher adult-controlled failure and child-controlled failure attributions than did mothers; these differences remained significant after controlling for parents' age, education, and possible social desirability bias. Significant positive correlations were found for mothers' and fathers' progressive attitudes, authoritarian attitudes, and modernity of attitudes after controlling for parents' age, education, and possible social desirability bias. CONCLUSIONS: We conclude that in Sweden fathers are more likely to attribute failures in caregiving situations both to themselves and to children than are mothers and that there is moderate concordance between fathers and mothers within the same family in progressive and authoritarian parenting attitudes.

IMP-J attitude control prelaunch analysis and operations plan

NASA Technical Reports Server (NTRS)

Hooper, H. L.; Mckendrew, J. B.; Repass, G. D.

1973-01-01

A description of the attitude control support being supplied for the Explorer 50 mission is given. Included in the document are descriptions of the computer programs being used to support attitude determination, prediction, and control for the mission and descriptions of the operating procedures that will be used to accomplish mission objectives.

The Relationship of Pupil Control Ideology to Students' Rights Attitudes.

ERIC Educational Resources Information Center

Jones, Lynn

As a result of increased court intervention in favor of students' rights, a review of a sample of teachers concerning their attitudes about student control was examined. Taking into consideration the teachers' attitudes concerning student rights, the Pupil Control Ideology test and the Students' Rights Acceptance Scale were used as measurement…

Exposure to Graphic Warning Labels on Cigarette Packages: Effects on Implicit and Explicit Attitudes toward Smoking among Young Adults

PubMed Central

Macy, Jonathan T.; Chassin, Laurie; Presson, Clark C.; Yeung, Ellen

2015-01-01

Objective Test the effect of exposure to the U.S. Food and Drug Administration’s proposed graphic images with text warning statements for cigarette packages on implicit and explicit attitudes toward smoking. Design and methods A two-session web-based study was conducted with 2192 young adults 18–25 years old. During session one, demographics, smoking behavior, and baseline implicit and explicit attitudes were assessed. Session two, completed on average 18 days later, contained random assignment to viewing one of three sets of cigarette packages, graphic images with text warnings, text warnings only, or current U.S Surgeon General’s text warnings. Participants then completed post-exposure measures of implicit and explicit attitudes. ANCOVAs tested the effect of condition on the outcomes, controlling for baseline attitudes. Results Smokers who viewed packages with graphic images plus text warnings demonstrated more negative implicit attitudes compared to smokers in the other conditions (p=.004). For the entire sample, explicit attitudes were more negative for those who viewed graphic images plus text warnings compared to those who viewed current U.S. Surgeon General’s text warnings (p=.014), but there was no difference compared to those who viewed text-only warnings. Conclusion Graphic health warnings on cigarette packages can influence young adult smokers’ implicit attitudes toward smoking. PMID:26442992

Spacecraft Hybrid (Mixed-Actuator) Attitude Control Experiences on NASA Science Missions

NASA Technical Reports Server (NTRS)

Dennehy, Cornelius J.

2014-01-01

There is a heightened interest within NASA for the design, development, and flight implementation of mixed-actuator hybrid attitude control systems for science spacecraft that have less than three functional reaction wheel actuators. This interest is driven by a number of recent reaction wheel failures on aging, but what could be still scientifically productive, NASA spacecraft if a successful hybrid attitude control mode can be implemented. Over the years, hybrid (mixed-actuator) control has been employed for contingency attitude control purposes on several NASA science mission spacecraft. This paper provides a historical perspective of NASA's previous engineering work on spacecraft mixed-actuator hybrid control approaches. An update of the current situation will also be provided emphasizing why NASA is now so interested in hybrid control. The results of the NASA Spacecraft Hybrid Attitude Control Workshop, held in April of 2013, will be highlighted. In particular, the lessons learned captured from that workshop will be shared in this paper. An update on the most recent experiences with hybrid control on the Kepler spacecraft will also be provided. This paper will close with some future considerations for hybrid spacecraft control.

Comparing three experiential learning methods and their effect on medical students' attitudes to learning communication skills.

PubMed

Koponen, Jonna; Pyörälä, Eeva; Isotalus, Pekka

2012-01-01

Despite numerous studies exploring medical students' attitudes to communication skills learning (CSL), there are apparently no studies comparing different experiential learning methods and their influence on students' attitudes. We compared medical students' attitudes to learning communication skills before and after a communication course in the data as a whole, by gender and when divided into three groups using different methods. Second-year medical students (n = 129) were randomly assigned to three groups. In group A (n = 42) the theatre in education method, in group B (n = 44) simulated patients and in group C (n = 43) role-play were used. The data were gathered before and after the course using Communication Skills Attitude Scale. Students' positive attitudes to learning communication skills (PAS; positive attitude scale) increased significantly and their negative attitudes (NAS; negative attitude scale) decreased significantly between the beginning and end of the course. Female students had more positive attitudes than the male students. There were no significant differences in the three groups in the mean scores for PAS or NAS measured before or after the course. The use of experiential methods and integrating communication skills training with visits to health centres may help medical students to appreciate the importance of CSL.

An investigation of quasi-inertial attitude control for a solar power satellite

NASA Technical Reports Server (NTRS)

Juang, J.-N.; Wang, S. J.

1982-01-01

An efficient means, a quasi-inertial attitude mode, is developed for maintaining the normal solar orientation of a space satellite for power collection in a synchronous orbit. Formulae are presented which establish the basic parametric properties for ideal quasi-inertial attitude and phasing. An active control system is necessary to compensate for the energy loss since energy dissipation in widely oscillating flexible bodies produces an instability of the quasi-inertial attitude in the sense that the spacecraft will tumble at the orbit rate. A fixed terminal time and state optimal control problem is formulated and an algorithm for determining the optimal control as a means for the periodical attitude and phase compensation is developed. The vehicle orientation affected by internal disturbance (structural flexibility) and external disturbances (e.g., drag forces) is maintained by a specialized controller design.

Perception of Locus of Control as a Predictor of Attitude Toward Students' Evaluation of University Faculty. AIR Forum Paper 1978.

ERIC Educational Resources Information Center

Kohler, Emmett T.; Christal, Melodie E.

Student and faculty attitudes about faculty evaluation and the relationship of the attitudes to the concept of locus of control were investigated. Student respondents consisted of 172 males and 256 females, and 108 faculty responses were received. The measure of locus of control closely resembles the Rotter Internal-External Control Scale. Student…

A longitudınal study on the effect of tailored training and counseling on the professional attitude of nursing students.

PubMed

Karadağ, Ayise; Hisar, Filiz; Göçmen Baykara, Zehra; Çalışkan, Nurcan; Karabulut, Hatice; Öztürk, Deniz

2015-01-01

The development of professional attitudes in nursing students is influenced by their learning experiences (knowledge, skills, and attitudes) and instructors' professional behaviors. Instructors can enhance students' professional attitude by organizing the training environment, being a role model, and providing counseling. This study was conducted as a tailoring intervention study over 4 years (2010-2013) examining 73 nursing students (34 intervention, 39 control) to determine the effect of training and counseling on nursing students' professional attitudes. Data were collected utilizing the Introductory Characteristics Form and the Instrument of Professional Attitude for Student Nurses. Intervention group students were provided training and counseling complementing their current education to develop their professional attitudes. Controls proceeded with their current education. Instrument for Professional Attitude for Student Nurses posttest scores of the intervention group were significantly higher than those of control group students. Furthermore, intervention group scores on all subscales other than "competence and continuous education" significantly increased after training. Controls showed no growth in professional attitudes, other than in "contribution to scientific knowledge." The training and counseling program had a positive influence on the professional attitudes of nursing students. Thus, providing tailored training and counseling associated to professionalism throughout the educational process at schools providing nursing training is recommended. Copyright © 2015 Elsevier Inc. All rights reserved.

Attitude determination with three-axis accelerometer for emergency atmospheric entry

NASA Technical Reports Server (NTRS)

Garcia-Llama, Eduardo (Inventor)

2012-01-01

Two algorithms are disclosed that, with the use of a 3-axis accelerometer, will be able to determine the angles of attack, sideslip and roll of a capsule-type spacecraft prior to entry (at very high altitudes, where the atmospheric density is still very low) and during entry. The invention relates to emergency situations in which no reliable attitude and attitude rate are available. Provided that the spacecraft would not attempt a guided entry without reliable attitude information, the objective of the entry system in such case would be to attempt a safe ballistic entry. A ballistic entry requires three controlled phases to be executed in sequence: First, cancel initial rates in case the spacecraft is tumbling; second, maneuver the capsule to a heat-shield-forward attitude, preferably to the trim attitude, to counteract the heat rate and heat load build up; and third, impart a ballistic bank or roll rate to null the average lift vector in order to prevent prolonged lift down situations. Being able to know the attitude, hence the attitude rate, will allow the control system (nominal or backup, automatic or manual) to cancel any initial angular rates. Also, since a heat-shield forward attitude and the trim attitude can be specified in terms of the angles of attack and sideslip, being able to determine the current attitude in terms of these angles will allow the control system to maneuver the vehicle to the desired attitude. Finally, being able to determine the roll angle will allow for the control of the roll ballistic rate during entry.

Sensor fault detection and recovery in satellite attitude control

NASA Astrophysics Data System (ADS)

Nasrolahi, Seiied Saeed; Abdollahi, Farzaneh

2018-04-01

This paper proposes an integrated sensor fault detection and recovery for the satellite attitude control system. By introducing a nonlinear observer, the healthy sensor measurements are provided. Considering attitude dynamics and kinematic, a novel observer is developed to detect the fault in angular rate as well as attitude sensors individually or simultaneously. There is no limit on type and configuration of attitude sensors. By designing a state feedback based control signal and Lyapunov stability criterion, the uniformly ultimately boundedness of tracking errors in the presence of sensor faults is guaranteed. Finally, simulation results are presented to illustrate the performance of the integrated scheme.

Autonomous spacecraft attitude control using magnetic torquing only

NASA Technical Reports Server (NTRS)

Musser, Keith L.; Ebert, Ward L.

1989-01-01

Magnetic torquing of spacecraft has been an important mechanism for attitude control since the earliest satellites were launched. Typically a magnetic control system has been used for precession/nutation damping for gravity-gradient stabilized satellites, momentum dumping for systems equipped with reaction wheels, or momentum-axis pointing for spinning and momentum-biased spacecraft. Although within the small satellite community there has always been interest in expensive, light-weight, and low-power attitude control systems, completely magnetic control systems have not been used for autonomous three-axis stabilized spacecraft due to the large computational requirements involved. As increasingly more powerful microprocessors have become available, this has become less of an impediment. These facts have motivated consideration of the all-magnetic attitude control system presented here. The problem of controlling spacecraft attitude using only magnetic torquing is cast into the form of the Linear Quadratic Regulator (LQR), resulting in a linear feedback control law. Since the geomagnetic field along a satellite trajectory is not constant, the system equations are time varying. As a result, the optimal feedback gains are time-varying. Orbit geometry is exploited to treat feedback gains as a function of position rather than time, making feasible the onboard solution of the optimal control problem. In simulations performed to date, the control laws have shown themselves to be fairly robust and a good candidate for an onboard attitude control system.

Farmers Knowledge, Attitudes, Practices and Health Problems Associated with Pesticide Use in Rural Irrigation Villages, Southwest Ethiopia

PubMed Central

Gesesew, Hailay Abrha; Woldemichael, Kifle; Massa, Desalegn; Mwanri, Lillian

2016-01-01

Background In Ethiopia, pesticides are widely used for a variety of purposes. The occurrence of contamination and poisoning for farmers is highly reported due to unsafe handling practices and their usage. We assessed knowledge, attitudes and experiences of previous pesticide exposure, and related health problems among farmers who use irrigation in Jimma Zone, Southwest Ethiopia. Methods A community based cross-sectional study was conducted among farmers living in the zone. Respondents were 796 irrigation farmers from 20 kebeles (lowest administration unit) in Jimma Zone. Data were collected using a pretested and structured questionnaire via face-to-face interviews. Both descriptive and inferential statistics analysis were performed. A binary logistic regression was used to identify factors associated with attitudes of farmers towards the safe use of pesticides at P value of ≤ 0.05 in the final model. Results Among the participants, 54.4% (95%CI, 50.7–58%) knew at least one pesticide control method and 53.7% had positive attitudes towards safe use of pesticide. The mean score of attitudes was found to be 3.9(±0.4). Knowledge including each of the following: the names of the pesticides (AOR, 0.41; 95%CI, 0.25–0.67), methods of pest control and the use of gloves during pesticide exposure (AOR, 1.52; 95%CI, 1.07–2.16) was found to be independent predictor of the farmers’ attitudes about safe use of pesticides. Past exposure of pesticide was reported by 89.6% of farmers. Participants reported ingestion (88.9%) and inhalation (90.4%) as possible mechanisms of pesticide exposure. Nearly 42% of farmers had never used any personal protective equipment (PPE) to protect themselves against pesticide exposure. Farmers reported several health complications, which were perceived as complications of pesticide exposure, including: headache, nausea and vomiting, skin rash and irritation and abdominal pain. Conclusions The study exposed the existence of high probability of pesticide exposure, the low safe use of pesticide and the low use of PPE. However, but farmers had positive attitudes towards safe use of pesticides. These findings appeal for the development of effective public health strategies to improve farmers’ awareness and safe use of PPE. In addition, there is a need to inform farmers about integrated pest management to prevent severe health complications, which may occur as a result of unsafe and inappropriate use of pesticides. PMID:27622668

Negative eating attitudes and behaviors among adolescents: The role of parental control and perceived peer support.

PubMed

Pace, Ugo; D'Urso, Giulio; Zappulla, Carla

2018-02-01

In the present study, we examined from a longitudinal perspective the relationship between parental (both maternal and paternal) psychological control, perceived peer support, and negative eating attitudes and behaviors, focusing on the moderating role that perceived peer support may play in the relationship between parental psychological control in early adolescence and negative eating attitudes and behaviors in late adolescence. In Wave 1, participants were 507 adolescents (249 boys and 258 girls) aged from 14 to 15 years (M = 14.76; SD = 0.63). Three years later (Wave 2), the same adolescents participated again in the study (M = 17.88 years; SD = 0.57). Regression analyses displayed that paternal, but not maternal, achievement-oriented psychological control during early adolescence positively predicted negative eating attitudes and behaviors in late adolescence, whereas perceived peer support negatively predicted negative eating attitudes and behaviors. Results also showed a moderator effect of perceived peer support in the relationship between father's psychological control and negative eating attitudes and behaviors, such that at higher levels of paternal achievement-oriented psychological control, negative eating attitudes and behaviors tended to be higher when perceived peer support was low and to be lower when perceived peer support was high. Copyright © 2017. Published by Elsevier Ltd.

Integrated Attitude Control Strategy for the Asteroid Redirect Mission

NASA Technical Reports Server (NTRS)

Lopez, Pedro, Jr.; Price, Hoppy; San Martin, Miguel

2014-01-01

A deep-space mission has been proposed to redirect an asteroid to a distant retrograde orbit around the moon using a robotic vehicle, the Asteroid Redirect Vehicle (ARV). In this orbit, astronauts will rendezvous with the ARV using the Orion spacecraft. The integrated attitude control concept that Orion will use for approach and docking and for mated operations will be described. Details of the ARV's attitude control system and its associated constraints for redirecting the asteroid to the distant retrograde orbit around the moon will be provided. Once Orion is docked to the ARV, an overall description of the mated stack attitude during all phases of the mission will be presented using a coordinate system that was developed for this mission. Next, the thermal and power constraints of both the ARV and Orion will be discussed as well as how they are used to define the optimal integrated stack attitude. Lastly, the lighting and communications constraints necessary for the crew's extravehicular activity planned to retrieve samples from the asteroid will be examined. Similarly, the joint attitude control strategy that employs both the Orion and the ARV attitude control assets prior, during, and after each extravehicular activity will also be thoroughly discussed.

Controlled randomized clinical trial of spirituality integrated psychotherapy, cognitive-behavioral therapy and medication intervention on depressive symptoms and dysfunctional attitudes in patients with dysthymic disorder.

PubMed

Ebrahimi, Amrollah; Neshatdoost, Hamid Taher; Mousavi, Seyed Ghafur; Asadollahi, Ghorban Ali; Nasiri, Hamid

2013-01-01

Due to the controversy over efficacy of cognitive-behavioral therapy for chronic depression, recently, there has been an increasingly tendency toward therapeutic methods based on the cultural and spiritual approaches. The aim of this research was to compare efficacy of spiritual integrated psychotherapy (SIPT) and cognitive-behavioral therapy (CBT) on the intensity of depression symptoms and dysfunctional attitudes of patients with dysthymic disorder. This study had a mixed qualitative and quantitative design. In the first phase, SIPT model was prepared and, in the second phase, a double-blind random clinical trial was performed. Sixty-two patients with dysthymic disorder were selected from several centers include Nour and Alzahra Medical Center, Counseling Centers of Isfahan University of Medical Sciences and Goldis in Isfahan. The participants were randomly assigned to three experimental groups and one control group. The first group received 8 sessions treatment of SIPT, second groups also had 8 sessions of cognitive-behavioral therapy, which was specific to dysthymic disorder and third group were under antidepressant treatment. Beck depression inventory and dysfunctional attitudes scale were used to evaluate all the participants in four measurement stages. The data were analyzed using MANCOVA repeated measure method. The results revealed that SIPT had more efficacy than medication based on both scales (P < 0.01); however, it was not different from CBT. SIPT was more effective on the modification of dysfunctional attitudes compared with CBT and medication (P < 0.05). These findings supported the efficacy of psychotherapy enriched with cultural capacities and religious teachings.

Design and Stability of an On-Orbit Attitude Control System Using Reaction Control Thrusters

NASA Technical Reports Server (NTRS)

Hall, Robert A.; Hough, Steven; Orphee, Carolina; Clements, Keith

2016-01-01

NASA is providing preliminary design and requirements for the Space Launch System Exploration Upper Stage (EUS). The EUS will provide upper stage capability for vehicle ascent as well as on-orbit control capability. Requirements include performance of on-orbit burn to provide Orion vehicle with escape velocity. On-orbit attitude control is accommodated by a on-off Reaction Control System (RCS). Paper provides overview of approaches for design and stability of an attitude control system using a RCS.

Helicopter flight-control design using an H(2) method

NASA Technical Reports Server (NTRS)

Takahashi, Marc D.

1991-01-01

Rate-command and attitude-command flight-control designs for a UH-60 helicopter in hover are presented and were synthesized using an H(2) method. Using weight functions, this method allows the direct shaping of the singular values of the sensitivity, complementary sensitivity, and control input transfer-function matrices to give acceptable feedback properties. The designs were implemented on the Vertical Motion Simulator, and four low-speed hover tasks were used to evaluate the control system characteristics. The pilot comments from the accel-decel, bob-up, hovering turn, and side-step tasks indicated good decoupling and quick response characteristics. However, an underlying roll PIO tendency was found to exist away from the hover condition, which was caused by a flap regressing mode with insufficient damping.

Application of Bounded Linear Stability Analysis Method for Metrics-Driven Adaptive Control

NASA Technical Reports Server (NTRS)

Bakhtiari-Nejad, Maryam; Nguyen, Nhan T.; Krishnakumar, Kalmanje

2009-01-01

This paper presents the application of Bounded Linear Stability Analysis (BLSA) method for metrics-driven adaptive control. The bounded linear stability analysis method is used for analyzing stability of adaptive control models, without linearizing the adaptive laws. Metrics-driven adaptive control introduces a notion that adaptation should be driven by some stability metrics to achieve robustness. By the application of bounded linear stability analysis method the adaptive gain is adjusted during the adaptation in order to meet certain phase margin requirements. Analysis of metrics-driven adaptive control is evaluated for a second order system that represents a pitch attitude control of a generic transport aircraft. The analysis shows that the system with the metrics-conforming variable adaptive gain becomes more robust to unmodeled dynamics or time delay. The effect of analysis time-window for BLSA is also evaluated in order to meet the stability margin criteria.

Spacecraft applications of advanced global positioning system technology

NASA Technical Reports Server (NTRS)

Huth, Gaylord; Dodds, James; Udalov, Sergei; Austin, Richard; Loomis, Peter; Duboraw, I. Newton, III

1988-01-01

The purpose of this study was to evaluate potential uses of Global Positioning System (GPS) in spacecraft applications in the following areas: attitude control and tracking; structural control; traffic control; and time base definition (synchronization). Each of these functions are addressed. Also addressed are the hardware related issues concerning the application of GPS technology and comparisons are provided with alternative instrumentation methods for specific functions required for an advanced low earth orbit spacecraft.

A Coarse-Alignment Method Based on the Optimal-REQUEST Algorithm

PubMed Central

Zhu, Yongyun

2018-01-01

In this paper, we proposed a coarse-alignment method for strapdown inertial navigation systems based on attitude determination. The observation vectors, which can be obtained by inertial sensors, usually contain various types of noise, which affects the convergence rate and the accuracy of the coarse alignment. Given this drawback, we studied an attitude-determination method named optimal-REQUEST, which is an optimal method for attitude determination that is based on observation vectors. Compared to the traditional attitude-determination method, the filtering gain of the proposed method is tuned autonomously; thus, the convergence rate of the attitude determination is faster than in the traditional method. Within the proposed method, we developed an iterative method for determining the attitude quaternion. We carried out simulation and turntable tests, which we used to validate the proposed method’s performance. The experiment’s results showed that the convergence rate of the proposed optimal-REQUEST algorithm is faster and that the coarse alignment’s stability is higher. In summary, the proposed method has a high applicability to practical systems. PMID:29337895

Using constructivist teaching strategies in high school science classrooms to cultivate positive attitudes toward science

NASA Astrophysics Data System (ADS)

Heron, Lory Elen

This study investigated the premise that the use of constructivist teaching strategies (independent variable) in high school science classrooms can cultivate positive attitudes toward science (dependent variable) in high school students. Data regarding the relationship between the use of constructivist strategies and change in student attitude toward science were collected using the Science Attitude Assessment Tool (SAAT) (Heron & Beauchamp, 1996). The format of this study used the pre-test, post-test, control group-experimental group design. The subjects in the study were high school students enrolled in biology, chemistry, or environmental science courses in two high schools in the western United States. Ten teachers and twenty-eight classes, involving a total of 249 students participated in the study. Six experimental group teachers and four control group teachers were each observed an average of six times using the Science Observation Guide (Chapman, 1995) to measure the frequency of observed constructivist behaviors. The mean for the control group teachers was 12.89 and the mean for experimental group teachers was 20.67; F(1, 8) = 16.2, p =.004, revealing teaching behaviors differed significantly between the two groups. After a four month experimental period, the pre-test and post-test SAAT scores were analyzed. Students received a score for their difference in positive attitude toward science. The null hypothesis stating there would be no change in attitude toward science as a subject, between students exposed to constructivist strategies, and students not exposed to constructivist strategies was rejected F(1, 247) = 8.04, p =.005. The control group had a generally higher reported grade in their last science class than the experimental group, yet the control group attitude toward science became more negative (-1.18) while attitude toward science in the experimental group became more positive (+1.34) after the four-month period. An analysis of positive attitude toward science vs. gender was undertaken. An initial significant difference in positive attitude toward science between females and males in the experimental group was established (p =.05). There was no significant difference in positive attitude toward science between those same females and males after the experimental period. Consistent with other results, attitudes toward science for both males and females in the control group became less positive after the study, while males and females in the experimental group had a more positive attitude toward science after four months of using constructivist strategies. Looking at females only, the control group started out with a significantly more positive attitude toward science (mean = 43.40) compared to the experimental group (mean = 39.26, p =.0261). Although a significant difference in positive attitude between females in both groups was not found after the treatment period, the mean attitude score for females in the experimental group increased 2.044, while the mean attitude score for females in the control group decreased by 1.750. Constructivist strategies and their relationship with fostering positive attitudes toward science, might prove a viable solution for addressing the major concern of gender equity and enrollment in higher level science and mathematics courses.

Three-Axis Time-Optimal Attitude Maneuvers of a Rigid-Body

NASA Astrophysics Data System (ADS)

Wang, Xijing; Li, Jisheng

With the development trends for modern satellites towards macro-scale and micro-scale, new demands are requested for its attitude adjustment. Precise pointing control and rapid maneuvering capabilities have long been part of many space missions. While the development of computer technology enables new optimal algorithms being used continuously, a powerful tool for solving problem is provided. Many papers about attitude adjustment have been published, the configurations of the spacecraft are considered rigid body with flexible parts or gyrostate-type systems. The object function always include minimum time or minimum fuel. During earlier satellite missions, the attitude acquisition was achieved by using the momentum ex change devices, performed by a sequential single-axis slewing strategy. Recently, the simultaneous three-axis minimum-time maneuver(reorientation) problems have been studied by many researchers. It is important to research the minimum-time maneuver of a rigid spacecraft within onboard power limits, because of potential space application such as surveying multiple targets in space and academic value. The minimum-time maneuver of a rigid spacecraft is a basic problem because the solutions for maneuvering flexible spacecraft are based on the solution to the rigid body slew problem. A new method for the open-loop solution for a rigid spacecraft maneuver is presented. Having neglected all perturbation torque, the necessary conditions of spacecraft from one state to another state can be determined. There is difference between single-axis with multi-axis. For single- axis analytical solution is possible and the switching line passing through the state-space origin belongs to parabolic. For multi-axis, it is impossible to get analytical solution due to the dynamic coupling between the axes and must be solved numerically. Proved by modern research, Euler axis rotations are quasi-time-optimal in general. On the basis of minimum value principles, a research for reorienting an inertial syrnmetric spacecraft with time cost function from an initial state of rest to a final state of rest is deduced. And the solution to it is stated below: Firstly, the essential condition for solving the problem is deduced with the minimum value principle. The necessary conditions for optimality yield a two point boundary-value problem (TPBVP), which, when solved, produces the control history that minimize time performance index. In the nonsingular control, the solution is the' bang-bang maneuver. The control profile is characterized by Saturated controls for the entire maneuver. The singular control maybe existed. It is only singular in mathematics. According to physical principle, the bigger the mode of the control torque is, the shorter the time is. So saturated controls are used in singular control. Secondly, the control parameters are always in maximum, so the key problem is to determine switch point thus original problem is changed to find the changing time. By the use of adjusting the switch on/off time, the genetic algorithm, which is a new robust method is optimized to determine the switch features without the gyroscopic coupling. There is improvement upon the traditional GA in this research. The homotopy method to find the nonlinear algebra is based on rigorous topology continuum theory. Based on the idea of the homotopy, the relaxation parameters are introduced, and the switch point is figured out with simulated annealing. Computer simulation results using a rigid body show that the new method is feasible and efficient. A practical method of computing approximate solutions to the time-optimal control- switch times for rigid body reorientation has been developed.

Using Science Activities To Internalize Locus of Control and Influence Attitudes towards Science.

ERIC Educational Resources Information Center

Rowland, Paul McD.

This study investigated the relationships between science activities that emphasize cause-and-effect and a learner's locus of control. Pretests included the Nowicki-Strickland Abbreviated Scale 7-12 to measure locus of control, and a modification of the Test of Science Related Attitudes to measure attitudes toward science. The findings suggest…

AE-C attitude determination and control prelaunch analysis and operations plan

NASA Technical Reports Server (NTRS)

Werking, R. D.; Headrick, R. D.; Manders, C. F.; Woolley, R. D.

1973-01-01

A description of attitude control support being supplied by the Mission and Data Operations Directorate is presented. Included are descriptions of the computer programs being used to support the missions for attitude determination, prediction, and control. In addition, descriptions of the operating procedures which will be used to accomplish mission objectives are provided.

Quaternion-based adaptive output feedback attitude control of spacecraft using Chebyshev neural networks.

PubMed

Zou, An-Min; Dev Kumar, Krishna; Hou, Zeng-Guang

2010-09-01

This paper investigates the problem of output feedback attitude control of an uncertain spacecraft. Two robust adaptive output feedback controllers based on Chebyshev neural networks (CNN) termed adaptive neural networks (NN) controller-I and adaptive NN controller-II are proposed for the attitude tracking control of spacecraft. The four-parameter representations (quaternion) are employed to describe the spacecraft attitude for global representation without singularities. The nonlinear reduced-order observer is used to estimate the derivative of the spacecraft output, and the CNN is introduced to further improve the control performance through approximating the spacecraft attitude motion. The implementation of the basis functions of the CNN used in the proposed controllers depends only on the desired signals, and the smooth robust compensator using the hyperbolic tangent function is employed to counteract the CNN approximation errors and external disturbances. The adaptive NN controller-II can efficiently avoid the over-estimation problem (i.e., the bound of the CNNs output is much larger than that of the approximated unknown function, and hence, the control input may be very large) existing in the adaptive NN controller-I. Both adaptive output feedback controllers using CNN can guarantee that all signals in the resulting closed-loop system are uniformly ultimately bounded. For performance comparisons, the standard adaptive controller using the linear parameterization of spacecraft attitude motion is also developed. Simulation studies are presented to show the advantages of the proposed CNN-based output feedback approach over the standard adaptive output feedback approach.

Influences on Intentions to Place Long-Acting Reversible Contraceptives: A Pilot Study Comparing According to Provider Specialty in Ohio.

PubMed

Thompson, Charee M; Broecker, Jane; Dade, Maggie; Nottingham, Kelly

2018-03-23

According to the American Academy of Pediatrics, pediatricians are to counsel and provide long-acting reversible contraceptives (LARCs) as first line of defense contraceptives because they are the most effective. We wanted to explore positive influences on LARC placement for pediatricians, particularly compared with providers in other specialties who care for women. Survey methods with data analyzed using analyses of variance and general linear models in statistical software SPSS version 24.0 (IBM Corp). Online survey. Participants were 224 providers across the state of Ohio who specialize in family medicine (51.8%), obstetrics/gynecology (17.9%), pediatrics (16.5%), and internal medicine (13.8%). Most of the sample was female (50.9%) and Caucasian (74.6%). The most frequent provider types were Doctors of Osteopathic Medicine (42.0%), followed by Doctors of Medicine (37.9%), and Certified Nurse Practitioners (8.5%). None. Attitudes about LARCs, perceived norms about placing LARCs, perceived behavioral control over placing LARCs, intentions to place LARCs. Means for all of the variables (attitudes, perceived norms, perceived behavioral control, and intentions to place) differed according to provider specialty. A pattern emerged across these variables in which internal medicine and pediatric practitioners reported lower attitudes, perceived norms, perceived behavioral control, and intentions to place LARCs than family medicine and obstetrics/gynecology practitioners, in that order. To increase positive attitudes and perceived norms about LARCs, professional organizations should increase communication to providers about the importance and expectations to place, counsel about, and facilitate placement of LARCs, and medical schooling can improve LARC counseling and procedural training to medical students, interns, and residents. Because perceived behavioral control is linked to intentions to place LARCs, perhaps providers would feel more confident to place them if they had more deliberate training. For pediatricians in particular, perhaps encouraging those who do not currently provide LARC methods to begin with training in implant placement would be a way to capitalize on their more favorable attitudes about implants. For pediatricians who do not feel comfortable providing device placement themselves, other strategies should be encouraged to facilitate provision of LARCs. Copyright © 2018 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

A Short Tutorial on Inertial Navigation System and Global Positioning System Integration

NASA Technical Reports Server (NTRS)

Smalling, Kyle M.; Eure, Kenneth W.

2015-01-01

The purpose of this document is to describe a simple method of integrating Inertial Navigation System (INS) information with Global Positioning System (GPS) information for an improved estimate of vehicle attitude and position. A simple two dimensional (2D) case is considered. The attitude estimates are derived from sensor data and used in the estimation of vehicle position and velocity through dead reckoning within the INS. The INS estimates are updated with GPS estimates using a Kalman filter. This tutorial is intended for the novice user with a focus on bringing the reader from raw sensor measurements to an integrated position and attitude estimate. An application is given using a remotely controlled ground vehicle operating in assumed 2D environment. The theory is developed first followed by an illustrative example.

Hamiltonian Dynamics of Spider-Type Multirotor Rigid Bodies Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doroshin, Anton V.

2010-03-01

This paper sets out to develop a spider-type multiple-rotor system which can be used for attitude control of spacecraft. The multirotor system contains a large number of rotor-equipped rays, so it was called a 'Spider-type System', also it can be called 'Rotary Hedgehog'. These systems allow using spinups and captures of conjugate rotors to perform compound attitude motion of spacecraft. The paper describes a new method of spacecraft attitude reorientation and new mathematical model of motion in Hamilton form. Hamiltonian dynamics of the system is investigated with the help of Andoyer-Deprit canonical variables. These variables allow obtaining exact solution formore » hetero- and homoclinic orbits in phase space of the system motion, which are very important for qualitative analysis.« less

Attitudes and beliefs as verbal behavior

PubMed Central

Guerin, Bernard

1994-01-01

Attitudes and beliefs are analyzed as verbal behavior. It is argued that shaping by a verbal community is an essential part of the formation and maintenance of both attitudes and beliefs, and it is suggested that verbal communities mediate the important shift in control from events in the environment (attitudes and beliefs as tacts) to control by other words (attitudes and beliefs as intraverbals). It appears that both attitudes and beliefs are constantly being socially negotiated through autoclitic functions. That is, verbal communities reinforce (a) reporting general rather than specific attitudes and beliefs, (b) presentation of intraverbals as if they were tacts, and (c) presentation of beliefs as if they were attitudes. Consistency among and between attitudes, beliefs, and behavior is also contingent upon the reinforcing practices of verbal communities. Thus, attitudes and beliefs can be studied as social behavior rather than as private, cognitive processes. PMID:22478181

Correlates of Young Men’s Intention to Discuss Birth Control with Female Partners

PubMed Central

Masters, N. Tatiana; Morrison, Diane M.; Querna, Katherine; Casey, Erin A.; Beadnell, Blair

2016-01-01

CONTEXT Heterosexually active men who wish to prevent conception, but are not willing to use condoms consistently, need to discuss birth control with female partners. Improving the understanding of correlates of men’s intention to have such discussions is one step toward supporting this health-facilitating behavior. METHODS A sample of 372 heterosexually active men aged 18–25 were recruited and surveyed online between December 2010 and June 2011. Men answered questions on attitudes toward, norms regarding and self-efficacy about discussing birth control, and about endorsement of two sexual scripts. Multiple regression analyses tested these measures’ associations with intention to discuss birth control, controlling for age and relationship status. RESULTS Attitudes, norms and self-efficacy were each positively associated with men’s intention to discuss birth control, accounting for 34% of variance. The more strongly men endorsed a traditional masculinity sexual script, the less likely they were to intend to discuss birth control (coefficient, −0.2). Endorsement of an alternative, gender-equitable “sex-positive woman” script, which emphasizes sexual pleasure and emotional connection as goals for both partners, had no association with intention. CONCLUSION Strategies that merit further exploration as potential supports for men’s intention to discuss birth control include improving men’s self-efficacy and positive attitudes and norms pertaining to such discussions, and reducing belief in traditionally masculine sexual scripts or transforming them to include discussing birth control. Future research should work both experimentally and longitudinally to document each element of the process that ends with men’s full participation in effective contraceptive use. PMID:27802365

Adaptive attitude control and momentum management for large-angle spacecraft maneuvers

NASA Technical Reports Server (NTRS)

Parlos, Alexander G.; Sunkel, John W.

1992-01-01

The fully coupled equations of motion are systematically linearized around an equilibrium point of a gravity gradient stabilized spacecraft, controlled by momentum exchange devices. These equations are then used for attitude control system design of an early Space Station Freedom flight configuration, demonstrating the errors caused by the improper approximation of the spacecraft dynamics. A full state feedback controller, incorporating gain-scheduled adaptation of the attitude gains, is developed for use during spacecraft on-orbit assembly or operations characterized by significant mass properties variations. The feasibility of the gain adaptation is demonstrated via a Space Station Freedom assembly sequence case study. The attitude controller stability robustness and transient performance during gain adaptation appear satisfactory.

Research on the attitude of small UAV based on MEMS devices

NASA Astrophysics Data System (ADS)

Shi, Xiaojie; Lu, Libin; Jin, Guodong; Tan, Lining

2017-05-01

This paper mainly introduces the research principle and implementation method of the small UAV navigation attitude system based on MEMS devices. The Gauss - Newton method based on least squares is used to calibrate the MEMS accelerometer and gyroscope for calibration. Improve the accuracy of the attitude by using the modified complementary filtering to correct the attitude angle error. The experimental data show that the design of the attitude and attitude system in this paper to meet the requirements of small UAV attitude accuracy to achieve a small, low cost.

On-orbit experience with the HEAO attitude control subsystem

NASA Technical Reports Server (NTRS)

Hoffman, D. P.; Berkery, E. A.

1978-01-01

The first satellite (HEAO-1) in the High Energy Astronomy Observatory Program series was launched successfully on Aug. 12, 1977. To date it has completed over nine months of orbital operation in a science data gathering mode. During this period all attitude control modes have been exercised and all primary mission objectives have been achieved. This paper highlights the characteristics of the attitude control subsystem design and compares the predicted performance with the actual flight operations experience. Environmental disturbance modeling, component hardware/software characteristics, and overall attitude control performance are reviewed and are found to compare very well with the prelaunch analytical predictions. Brief comments are also included regarding the operations aspects of the attitude control subsystem. The experience in this regard demonstrates the effectiveness of the design flexibility afforded by the presence of a general purpose digital processor in the subsystem flight hardware implementation.

An automated method of tuning an attitude estimator

NASA Technical Reports Server (NTRS)

Mason, Paul A. C.; Mook, D. Joseph

1995-01-01

Attitude determination is a major element of the operation and maintenance of a spacecraft. There are several existing methods of determining the attitude of a spacecraft. One of the most commonly used methods utilizes the Kalman filter to estimate the attitude of the spacecraft. Given an accurate model of a system and adequate observations, a Kalman filter can produce accurate estimates of the attitude. If the system model, filter parameters, or observations are inaccurate, the attitude estimates may be degraded. Therefore, it is advantageous to develop a method of automatically tuning the Kalman filter to produce the accurate estimates. In this paper, a three-axis attitude determination Kalman filter, which uses only magnetometer measurements, is developed and tested using real data. The appropriate filter parameters are found via the Process Noise Covariance Estimator (PNCE). The PNCE provides an optimal criterion for determining the best filter parameters.

The status and predictors of hypertension preventive nutritional behaviors in adolescents based on the constructs of the Theory of Planned Behavior

PubMed Central

Matlabi, Mohammad; Esmaeili, Reza; Moshki, Mahdi; Ranaei, Afsaneh; Mehrabi, Rahele

2018-01-01

Background Malnutrition is an important factor affecting hypertensive incidence. Since the unhealthiest nutritional behaviors are rooted in childhood attitudes and experiences, applying educational interventions to these age groups will be most useful in the formation of preventive nutritional behaviors. Objective To determine the predictive power of the TPB on hypertension in junior high-school students. Methods The present cross-sectional study was conducted on 160 junior high-school students in Kashmar, Iran in academic year commencing 2-13-2014, selected through random sampling. The participants completed a researcher-made questionnaire consisting of a demographic information form and a section to evaluate the constructs of the TPB. The data collected were analyzed in SPSS-16 using the correlation Wilcoxon statistics test, the one-way ANOVA and multiple linear regression analysis. Results The mean age of the students was 13.51. A total of 47% of the students had snacked on potato chips and cheese puffs, 45% had eaten high-fat foods and 51.2% had eaten cookies and chocolates within the past week. The variable of behavioral intention predicted 32% of the variations in preventive nutritional behaviors by itself. The Pearson product-moment correlation analysis found that hypertension preventive nutritional behaviors were significantly correlated with attitude (p<0.001, r=0.38), perceived behavioral control (p<0.001, r=0.38), and behavioral intention. Moreover, significant correlations were observed between subjective norms and attitude (p<0.028, r=0.173), perceived behavioral control and attitude (p<0.003, r=0.231), behavioral intention and attitude (p<0.001, r=0.370), behavioral intention and subjective norms (p<0.030, r=0.171) and between behavioral intention and perceived behavioral control (p<0.001, r=0.484). Conclusion The examined students revealed an adequate adherence to preventive nutritional behaviors. Nutrition education interventions should be developed based on variables such as behavioral intention and its determinants, i.e. attitude, perceived behavioral control and subjective norms. PMID:29588824

The forgotten smoker: a qualitative study of attitudes towards smoking, quitting, and tobacco control policies among continuing smokers.

PubMed

Uppal, Navneet; Shahab, Lion; Britton, John; Ratschen, Elena

2013-05-03

Although research suggests that the majority of smokers want to quit smoking, the uptake of Stop Smoking Services, designed to assist smokers with quitting, remains low. Little is known about continuing smokers who do not access these services, and opportunities to influence their motivation and encourage quit attempts through the uptake of services. Using PRIME theory, this study explored differences between continuing smokers who had varying levels of motivation to quit, in terms of their plans to quit, evaluative beliefs about smoking, cigarette dependence, and attitudes towards tobacco control policies and services. Twenty-two current smokers, recruited from the community, were classified by motivation level to quit using a self-report questionnaire (two groups: high/low). Four focus groups (n=13) and individual interviews (n=9) were conducted with both groups using an interview guide incorporating aspects of PRIME theory. Discussion areas included motives for smoking, attitudes towards smoking and quitting, perceptions of dependence, motives for quitting, barriers to quitting, and attitudes towards existing and impending tobacco control policies and services. Verbatim transcripts were analysed using thematic framework analysis. All participants expressed low motivation to quit during discussions, despite some initially self-classifying as having high explicit levels of motivation to quit. Both groups reported similar attitudes towards smoking and quitting, including a perceived psychological addiction to smoking, positive evaluations about smoking which inhibited plans to quit, and similar suggested methods to increase motivation (simply wanting to, save money, improve health). Most felt that they 'ought' to quit as opposed to 'wanted' to. Little influence was ascribed towards tobacco control policies such as plain packaging and hidden sales displays, and participants felt that price increases of tobacco products needed to be considerable in order to influence motivation. Highly motivated smokers expressed more willingness to visit Stop Smoking Services, although none had done so. Continuing smokers' attitudes towards smoking and quitting suggests that research and policy need to focus on increasing smokers' implicit motivation to quit smoking, even for those who classified themselves as having high motivation to quit. Targeted information and further education about Stop Smoking Services is required to increase uptake.

RECOGNIZING FARMERS' ATTITUDES AND IMPLEMENTING NONPOINT SOURCE POLLUTION CONTROL POLICIES

EPA Science Inventory

This report examines the role of farmer attitudes and corresponding communication activities in the implementation of nonpoint source water pollution control programs. The report begins with an examination of the basis for and function of attitudes in influencing behavior. The ro...

Attitude output feedback control for rigid spacecraft with finite-time convergence.

PubMed

Hu, Qinglei; Niu, Guanglin

2017-09-01

The main problem addressed is the quaternion-based attitude stabilization control of rigid spacecraft without angular velocity measurements in the presence of external disturbances and reaction wheel friction as well. As a stepping stone, an angular velocity observer is proposed for the attitude control of a rigid body in the absence of angular velocity measurements. The observer design ensures finite-time convergence of angular velocity state estimation errors irrespective of the control torque or the initial attitude state of the spacecraft. Then, a novel finite-time control law is employed as the controller in which the estimate of the angular velocity is used directly. It is then shown that the observer and the controlled system form a cascaded structure, which allows the application of the finite-time stability theory of cascaded systems to prove the finite-time stability of the closed-loop system. A rigorous analysis of the proposed formulation is provided and numerical simulation studies are presented to help illustrate the effectiveness of the angular-velocity observer for rigid spacecraft attitude control. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Promoting Individual Learning for Trainees with Perceived High Helplessness: Experiences of a Safety Training Program

PubMed Central

Kiani, Fariba; Khodabakhsh, Mohamad Reza

2014-01-01

Objective: The article arises from a research project investigating the effectiveness of safety training on changing attitudes toward safety issues. Followed by the training intervention was observed that employees’ helplessness decreased. The researchers have come to the idea of investigating how safety training can reduce perceived helplessness. Thus, this research examined the effectiveness of safety training on reducing employees’ helplessness with attention to the mediating role of attitude toward safety issues. Methods: The current study was an experimental study with the control group. A total of 204 (101 experimental group and 103 control group) completed safety attitude questionnaire and perceived helplessness before a safety training course including four 90-min sessions over 4 consecutive days in Esfahan Steel Company in 2012 between October and December. Only members of the experimental group participated in this course. These questionnaires, approximately 30 days later, again were run on members of both groups. Data were analyzed using descriptive indexes, t-, and F-test. Results: Results by comparing the two groups showed that safety training was effective only on individuals with perceived low helplessness (p = 0.02). Conclusion: In individuals with perceived high helplessness, safety training only with changing safety attitudes can reduce the perceived helplessness. PMID:25798170

Precision Attitude Control for the BETTII Balloon-Borne Interferometer

NASA Technical Reports Server (NTRS)

Benford, Dominic J.; Fixsen, Dale J.; Rinehart. Stephen

2012-01-01

The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-meter baseline far-infrared interferometer to fly on a high altitude balloon. Operating at wavelengths of 30-90 microns, BETTII will obtain spatial and spectral information on science targets at angular resolutions down to less than half an arcsecond, a capability unmatched by other far-infrared facilities. This requires attitude control at a level ofless than a tenth of an arcsecond, a great challenge for a lightweight balloon-borne system. We have designed a precision attitude determination system to provide gondola attitude knowledge at a level of 2 milliarcseconds at rates up to 100Hz, with accurate absolute attitude determination at the half arcsecond level at rates of up to 10Hz. A mUlti-stage control system involving rigid body motion and tip-tilt-piston correction provides precision pointing stability to the level required for the far-infrared instrument to perform its spatial/spectral interferometry in an open-loop control. We present key aspects of the design of the attitude determination and control and its development status.

Illness Perceptions in Patients of Schizophrenia: A Preliminary Investigation from Lahore, Pakistan

PubMed Central

Hussain, Sadia; Imran, Nazish; Hotiana, Usman Amin; Mazhar, Nauman; Asif, Aftab

2017-01-01

Background and Objective: Patient’s perception of their illness influences their healthcare decisions. The objectives of this study were to explore patient’s own beliefs about their illness (Schizophrenia) and perceived social support, and its impact on their attitudes toward pharmacological treatment in Lahore, Pakistan. Methods: This study was conducted at Mayo Hospital Lahore from March to September 2016. Hundred individuals suffering from Schizophrenia completed four questionnaires; a socio-demographic questionnaire, the Illness Perception Questionnaire for Schizophrenia(IPQ-S), Drug attitude Inventory-10 (DAI) and Multidimensional Scale of Perceived Social Support (PSS). Results: Stress, family problems, lack of friends & financial worries were endorsed strongly by patients as cause of their mental illness. Ambiguity regarding their mental illness duration and personal control was observed. Patients’ perceived significant negative consequences, negative emotional response, as well as had poor understanding of their mental illness and treatment effectiveness. Statistically significant gender differences in treatment control and illness coherence subscales of IPQS were observed. Drug attitude inventory was positively correlated with Treatment control subscale (p < .01) and negatively correlated with Illness coherence subscale of IPQS (p < .05). The negative consequences subscale and perceived social support was negatively correlated (p < .01). Conclusion: Patient’s perception about their own illness is predictor of their drug taking attitude and perceived social support. Study results should help to develop new interventions to correct inaccurate beliefs in patients with schizophrenia to improve illness outcome. PMID:29067048

Magsat attitude dynamics and control: Some observations and explanations

NASA Technical Reports Server (NTRS)

Stengle, T. H.

1980-01-01

Before its reentry 7 months after launch, Magsat transmitted an abundance of valuable data for mapping the Earth's magnetic field. As an added benefit, a wealth of attitude data for study by spacecraft dynamicists was also collected. Because of its unique configuration, Magsat presented new control problems. With its aerodynamic trim boom, attitude control was given an added dimension. Minimization of attitude drift, which could be mapped in relative detail, became the goal. Momentum control, which was accomplished by pitching the spacecraft in order to balance aerodynamic and gravity gradient torques, was seldom difficult to achieve. Several interesting phenomena observed as part of this activity included occasional momentum wheel instability and a rough correlation between solar flux and the pitch angle required to maintain acceptable momentum. An overview is presented of the attitude behavior of Magsat and some of the control problems encountered. Plausible explanations for some of this behavior are offered. Some of the control philosophy used during the mission is examined and aerodynamic trimming operations are summarized.

MSFC Skylab attitude and pointing control system mission evaluation

NASA Technical Reports Server (NTRS)

Chubb, W. B.

1974-01-01

The results of detailed performance analyses of the attitude and pointing control system in-orbit hardware and software on Skylab are reported. Performance is compared with requirements, test results, and prelaunch predictions. A brief history of the altitude and pointing control system evolution leading to the launch configuration is presented. The report states that the attitude and pointing system satisfied all requirements.

Knowledge and attitude towards Ebola and Marburg virus diseases in Uganda using quantitative and participatory epidemiology techniques

PubMed Central

Skjerve, Eystein; Nabadda, Daisy; Sitali, Doreen Chilolo; Mumba, Chisoni; Mwiine, Frank N.; Lutwama, Julius J.; Balinandi, Stephen; Shoemaker, Trevor; Kankya, Clovice

2017-01-01

Background Uganda has reported five (5) Ebola virus disease outbreaks and three (3) Marburg virus disease outbreaks from 2000 to 2016. Peoples’ knowledge and attitude towards Ebola and Marburg virus disease impact on control and prevention measures especially during outbreaks. We describe knowledge and attitude towards Ebola and Marburg virus outbreaks in two affected communities in Uganda to inform future outbreak responses and help in the design of health education and communication messages. Methods The study was a community survey done in Luweero, Ibanda and Kamwenge districts that have experienced outbreaks of Ebola and Marburg virus diseases. Quantitative data were collected using a structured questionnaire and triangulated with qualitative participatory epidemiology techniques to gain a communities’ knowledge and attitude towards Ebola and Marburg virus disease. Results Out of 740 respondents, 48.5% (359/740) were categorized as being knowledgeable about Ebola and Marburg virus diseases, whereas 60.5% (448/740) were having a positive attitude towards control and prevention of Ebola and Marburg virus diseases. The mean knowledge and attitude percentage scores were 54.3 (SD = 23.5, 95%CI = 52.6–56.0) and 69.9 (SD = 16.9, 95%CI = 68.9–71.1) respectively. People educated beyond primary school were more likely to be knowledgeable about Ebola and Marburg virus disease than those who did not attain any formal education (OR = 3.6, 95%CI = 2.1–6.1). Qualitative data revealed that communities describe Ebola and Marburg virus diseases as very severe diseases with no cure and they believe the diseases spread so fast. Respondents reported fear and stigma suffered by survivors, their families and the broader community due to these diseases. Conclusion Communities in Uganda affected by filovirus outbreaks have moderate knowledge about these diseases and have a positive attitude towards practices to prevent and control Ebola and Marburg viral diseases. The public health sector should enhance this community knowledge gap to empower them more by supplying educational materials for epidemic preparedness in future using appropriate communication channels as proposed by the communities. PMID:28892520

The MK VI - A second generation attitude control system

NASA Astrophysics Data System (ADS)

Meredith, P. J.

1986-10-01

The MK VI, a new multipurpose attitude control system for the exoatmospheric attitude control of sounding rocket payloads, is described. The system employs reprogrammable microcomputer memory for storage of basic control logic and for specific mission event control data. The paper includes descriptions of MK VI specifications and configuration; sensor characteristics; the electronic, analog, and digital sections; the pneumatic system; ground equipment; the system operation; and software. A review of the MK VI performance for the Comet Halley flight is presented. Block diagrams are included.

Dynamics and Control of Attitude, Power, and Momentum for a Spacecraft Using Flywheels and Control Moment Gyroscopes

NASA Technical Reports Server (NTRS)

Roithmayr, Carlos M.; Karlgaard, Christopher D.; Kumar, Renjith R.; Seywald, Hans; Bose, David M.

2003-01-01

Several laws are designed for simultaneous control of the orientation of an Earth-pointing spacecraft, the energy stored by counter-rotating flywheels, and the angular momentum of the flywheels and control moment gyroscopes used together as an integrated set of actuators for attitude control. General, nonlinear equations of motion are presented in vector-dyadic form, and used to obtain approximate expressions which are then linearized in preparation for design of control laws that include feedback of flywheel kinetic energy error as a means of compensating for damping exerted by rotor bearings. Two flywheel steering laws are developed such that torque commanded by an attitude control law is achieved while energy is stored or discharged at the required rate. Using the International Space Station as an example, numerical simulations are performed to demonstrate control about a torque equilibrium attitude, and illustrate the benefits of kinetic energy error feedback. Control laws for attitude hold are also developed, and used to show the amount of propellant that can be saved when flywheels assist the CMGs. Nonlinear control laws for large-angle slew maneuvers perform well, but excessive momentum is required to reorient a vehicle like the International Space Station.

A randomised controlled trial to explore attitudes to routine scale and polish and compare manual versus ultrasonic scaling in the general dental service in Scotland [ISRCTN99609795

PubMed Central

Bonner, Brian C; Young, Linda; Smith, Patricia A; McCombes, Wendy; Clarkson, Jan E

2005-01-01

Background To investigate, within general dental practice, patients' and vocational dental practitioners' (VDP) attitudes towards the benefits and costs of a simple scale and polish and to compare the experience of using manual versus ultrasonic instruments to scale teeth. Methods 28 VDPs and 420 patients participated. Patients were randomly allocated to either group. Patients' and VDPs' attitudes towards, and experience of, the scale and polish were elicited by means of self-administered questionnaires. Results The majority of patients (99%) believed a scale and polish was beneficial. VDPs considered ultrasonic treatment to be appropriate on significantly more occasions than they did for manual scale and polish (P < 0.001). Patient discomfort: with ultrasonic scaling 69.2% felt 'a little uncomfortable' or worse compared with 60% of those undergoing manual treatment (P = 0.072). VDPs considered treatment charges were appropriate for 77% of patients. Conclusion Routine scaling and polishing is considered beneficial by both patients and vocational trainees. The majority of patients, regardless of treatment method, experience some degree of discomfort when undergoing a scale and polish. VDPs showed a preference for the ultrasonic treatment method. PMID:15975140

Estimating the Inertia Matrix of a Spacecraft

NASA Technical Reports Server (NTRS)

Acikmese, Behcet; Keim, Jason; Shields, Joel

2007-01-01

A paper presents a method of utilizing some flight data, aboard a spacecraft that includes reaction wheels for attitude control, to estimate the inertia matrix of the spacecraft. The required data are digitized samples of (1) the spacecraft attitude in an inertial reference frame as measured, for example, by use of a star tracker and (2) speeds of rotation of the reaction wheels, the moments of inertia of which are deemed to be known. Starting from the classical equations for conservation of angular momentum of a rigid body, the inertia-matrix-estimation problem is formulated as a constrained least-squares minimization problem with explicit bounds on the inertia matrix incorporated as linear matrix inequalities. The explicit bounds reflect physical bounds on the inertia matrix and reduce the volume of data that must be processed to obtain a solution. The resulting minimization problem is a semidefinite optimization problem that can be solved efficiently, with guaranteed convergence to the global optimum, by use of readily available algorithms. In a test case involving a model attitude platform rotating on an air bearing, it is shown that, relative to a prior method, the present method produces better estimates from few data.

Attitudes toward euthanasia and physician-assisted suicide: a study of the multivariate effects of healthcare training, patient characteristics, religion and locus of control.

PubMed

Hains, Carrie-Anne Marie; Hulbert-Williams, Nicholas J

2013-11-01

Public and healthcare professionals differ in their attitudes towards euthanasia and physician-assisted suicide (PAS), the legal status of which is currently in the spotlight in the UK. In addition to medical training and experience, religiosity, locus of control and patient characteristics (eg, patient age, pain levels, number of euthanasia requests) are known influencing factors. Previous research tends toward basic designs reporting on attitudes in the context of just one or two potentially influencing factors; we aimed to test the comparative importance of a larger range of variables in a sample of nursing trainees and non-nursing controls. One hundred and fifty-one undergraduate students (early-stage nursing training, late-stage nursing training and non-nursing controls) were approached on a UK university campus and asked to complete a self-report questionnaire. Participants were of mixed gender and were on average 25.5 years old. No significant differences in attitude were found between nursing and non-nursing students. There was a significant positive correlation between higher religiosity and positive attitude toward euthanasia (r=0.19, p<0.05) and a significant negative relationship between internal locus of control and positive attitude toward PAS (r=-0.263, p<0.01). Multivariate analyses revealed differing predictor models for attitudes towards euthanasia and PAS, and confirm the importance of individual differences in determining these attitudes. The unexpected direction of association between religiosity and attitudes may reflect a broader cultural shift in attitudes since earlier research in this area. Furthermore, these findings suggest it possible that experience, more than training itself, may be a bigger influence on attitudinal differences in healthcare professionals.

Quaternion normalization in spacecraft attitude determination

NASA Technical Reports Server (NTRS)

Deutschmann, Julie; Bar-Itzhack, Itzhack; Galal, Ken

1992-01-01

Methods are presented to normalize the attitude quaternion in two extended Kalman filters (EKF), namely, the multiplicative EKF (MEKF) and the additive EKF (AEKF). It is concluded that all the normalization methods work well and yield comparable results. In the AEKF, normalization is not essential, since the data chosen for the test do not have a rapidly varying attitude. In the MEKF, normalization is necessary to avoid divergence of the attitude estimate. All of the methods of the methods behave similarly when the spacecraft experiences low angular rates.

Aerial robot intelligent control method based on back-stepping

NASA Astrophysics Data System (ADS)

Zhou, Jian; Xue, Qian

2018-05-01

The aerial robot is characterized as strong nonlinearity, high coupling and parameter uncertainty, a self-adaptive back-stepping control method based on neural network is proposed in this paper. The uncertain part of the aerial robot model is compensated online by the neural network of Cerebellum Model Articulation Controller and robust control items are designed to overcome the uncertainty error of the system during online learning. At the same time, particle swarm algorithm is used to optimize and fix parameters so as to improve the dynamic performance, and control law is obtained by the recursion of back-stepping regression. Simulation results show that the designed control law has desired attitude tracking performance and good robustness in case of uncertainties and large errors in the model parameters.

An approach to the design and implementation of spacecraft attitude control systems

NASA Technical Reports Server (NTRS)

ODonnell, James R., Jr.; Mangus, David J.

1998-01-01

Over 39 years and a long list of missions, the guidance, navigation, and control (GN&C) groups at the Goddard Space Flight Center have gradually developed approaches to the design and implementation of successful spacecraft attitude control systems. With the recent creation of the Guidance, Navigation, and Control Center at Goddard, there is a desire to document some of these design practices to help to ensure their consistent application in the future. In this paper, we will discuss the beginnings of this effort, drawing primarily on the experience of one of the past attitude control system (ACS) groups at Goddard (what was formerly known as Code 712, the Guidance, Navigation, and Control Branch). We will discuss the analysis and design methods and criteria used, including guidelines for linear and nonlinear analysis, as well as the use of low- and high-fidelity simulation for system design and verification of performance. Descriptions of typical ACS sensor and actuator hardware will be shown, and typical sensor/actuator suites for a variety of mission types detailed. A description of the software and hardware test effort will be given, along with an attempt to make some qualitative estimates on how much effort is involved. The spacecraft and GN&C subsystem review cycles will be discussed, giving an outline of what design reviews are typically held and what information should be presented at each stage. Finally, we will point out some of the lessons learned at Goddard.

An Approach to the Design and Implementation of Spacecraft Attitude Control Systems

NASA Technical Reports Server (NTRS)

ODonnell, James R., Jr.; Mangus, David J.

1998-01-01

Over 39 years and a long list of missions, the guidance, navigation, and control (GN&C) groups at the Goddard Space Flight Center have gradually developed approaches to the design and implementation of successful spacecraft attitude control systems. With the recent creation of the Guidance, Navigation, and Control Center at Goddard, there is a desire to document some of these design practices to help to ensure their consistent application in the future. In this paper, we will discuss the beginnings of this effort, drawing primarily on the experience of one of the past attitude control system (ACS) groups at Goddard (what was formerly known as Code 712, the Guidance, Navigation, and Control Branch). We will discuss the analysis and design methods and criteria used, including guidelines for linear and nonlinear analysis, as well as the use of low- and high-fidelity simulation for system design and verification of performance. Descriptions of typical ACS sensor and actuator hardware will be shown, and typical sensor/actuator suites for a variety of mission types detailed. A description of the software and hardware test effort will be given, along with an attempt to make some qualitative estimates on how much effort is involved. The spacecraft and GN&C subsystem review cycles will be discussed, giving an outline of what design reviews are typically held and .what information should be presented at each stage. Finally, we will point out some of the lessons learned at Goddard.

Attitudes of eighth-grade honors students toward the conceptual change methods of teaching science

NASA Astrophysics Data System (ADS)

Heide, Clifford Lee

1998-12-01

The study researched the attitude of eighth grade honors science students toward the steps of the conceptual change teaching method. The attitudes of 25 students in an honors 8th grade science class in the Greater Phoenix metropolitan area were assessed using a multi-method approach. A quantitative method (student survey) and a qualitative method (focus group) were triangulated for convergence. Since conceptual change is a relatively new reform teaching modality, the study assessed students' attitudes utilizing this method. Conceptual change teaching is characterized by connections between concepts and facts which are organized around key ideas. Knowledge connected through concepts is constantly revised and edited by students as they continue to learn and add new concepts. The results of this study produced evidence that the conceptual change method of teaching science and its six process steps have qualities that foster positive student attitude. The study demonstrated that students' attitudes toward science is positively influenced through the conceptual change teaching method by enabling students to: (1) choose problems and find solutions to those problems (student directed); (2) work together in large and small groups; (3) learn through student oral presentations; (4) perform hands-on laboratory experiences; (5) learn through conceptual understanding not memorization; (6) implement higher order learning skills to make connections from the lab to the real world. Teachers can use the information in the study to become aware of the positive and negative attitudes of students taught with the conceptual change method. Even if the conceptual change teaching strategy is not the modality utilized by an educator, the factors identified by this study that affect student attitude could be used to help a teacher design lesson plans that help foster positive student attitudes.

The Assessment of Family Functions, Dyadic Adjustment, and Parental Attitude in Adolescents with Substance Use Disorder

PubMed Central

ÖNGEL ATAR, Ayça; YALÇIN, Özhan; UYGUN, Ersin; ÇİFTÇİ DEMİRCİ, Arzu; ERDOĞAN, Ayten

2016-01-01

Introduction Family structure and family attitudes have been reported to be important factors in the development of substance use disorders. In this study, we aimed to assess the relationship between substance use and family functions, parental attitude, and parental dyadic adjustment of adolescents with substance use disorder. Methods The study was conducted on 50 patients, comprising 9 female and 41 male adolescents between the ages of 14 and 18 years, treated at Bakırköy Mental Health Hospital, Substance Abuse Research, Treatment and Education Center for Children Adolescents (ÇEMATEM), Turkey, with the diagnosis of substance use disorder according to DSM-5 and their parents and a control group comprising 50 healthy adolescents without any psychopathology or substance use disorder and their parents. The study was designed as a matched case–control study for age and gender. Sociodemographic Data Form (SDF), Parental Attitude Scale (PAS), Dyadic Adjustment Scale (DAS), and Family Assessment Device (FAD) were applied to both groups. Results When the study and control groups were compared with regard to the PAS, the study group scores determined for “involvement-acceptance,” “psychological autonomy,” and “control-supervision” dimensions were significantly lower than the control group scores. Compared with the control group, dyadic adjustment was lower in terms of “dyadic cohesion,” “dyadic consensus,” and “affectional expression.” Living with biological parents and the togetherness of parents were lower in the study group. “Problem solving,” “communication,” “roles,” “affective responsiveness,” “affective involvement,” “behavior control,” and “general functioning” dimension scores according to FAD were also significantly higher in the study group. Conclusion Compared with togetherness of the controls, the dyadic adjustment of their parents was lower and family functions as perceived by the parents and adolescents were unhealthier in the adolescents using substances. These findings indicate that the family functions, dyadic adjustment, and parental attitude styles need to be assessed in the risk groups to determine familial risk factors and to structure protective measures. These assessments may guide clinicians and policy-makers toward good clinical practice and help build protective measures. PMID:28360764

A pilot's assessment of helicopter handling-quality factors common to both agility and instrument flying tasks

NASA Technical Reports Server (NTRS)

Gerdes, R. M.

1980-01-01

A series of simulation and flight investigations were undertaken to evaluate helicopter flying qualities and the effects of control system augmentation for nap-of-the-Earth (NOE) agility and instrument flying tasks. Handling quality factors common to both tasks were identified. Precise attitude control was determined to be a key requirement for successful accomplishment of both tasks. Factors that degraded attitude controllability were improper levels of control sensitivity and damping, and rotor system cross coupling due to helicopter angular rate and collective pitch input. Application of rate command, attitude command, and control input decouple augmentation schemes enhanced attitude control and significantly improved handling qualities for both tasks. The NOE agility and instrument flying handling quality considerations, pilot rating philosophy, and supplemental flight evaluations are also discussed.

A system for spacecraft attitude control and energy storage

NASA Technical Reports Server (NTRS)

Shaughnessy, J. D.

1974-01-01

A conceptual design for a double-gimbal reaction-wheel energy-wheel device which has three-axis attitude control and electrical energy storage capability is given. A mathematical model for the three-axis gyroscope (TAG) was developed, and a system of multiple units is proposed for attitude control and energy storage for a class of spacecraft. Control laws were derived to provide the required attitude-control torques and energy transfer while minimizing functions of TAG gimbal angles, gimbal rates, reaction-wheel speeds, and energy-wheel speed differences. A control law is also presented for a magnetic torquer desaturation system. A computer simulation of a three-TAG system for an orbiting telescope was used to evaluate the concept. The results of the study indicate that all control and power requirements can be satisfied by using the TAG concept.

[State of health, eating and body image disorders among employees in the beauty industry].

PubMed

Lukács-Márton, Réka; Szabó, Pál

2013-04-28

Beauticians are considered as risk populations for eating disorders and body image disorders, as their work is closely related to beauty and fashion. The aim of the authors was to examine whether eating and body image disorders occur more frequently among beauticians than in control subjects. Eating disorders were assessed using the Eating Attitudes Test, Eating Behaviour Severity Scale, and body image measures included the Human Figure Drawings Test, the Body Dissatisfaction Subscale of the Eating Disorders Inventory, the Body Attitudes Test, and the Body Investment Scale. The study sample included 56 beauticians from Transylvania and 59 from Hungary. These groups were compared with control groups including 57 subjects from Transylvania and 54 subjects from Hungary. Questionnaire data were analysed. The occurrence of weight reducing methods such as binge eating was significantly more prevalent in the beautician groups than in controls. Subclinical eating disorders were more frequent in the Transylvanian beautician group. Clinical and subclinical eating disorders occur more frequently in beauticians than in control subjects.

Comparison of two on-orbit attitude sensor alignment methods

NASA Technical Reports Server (NTRS)

Krack, Kenneth; Lambertson, Michael; Markley, F. Landis

1990-01-01

Compared here are two methods of on-orbit alignment of vector attitude sensors. The first method uses the angular difference between simultaneous measurements from two or more sensors. These angles are compared to the angular differences between the respective reference positions of the sensed objects. The alignments of the sensors are adjusted to minimize the difference between the two sets of angles. In the second method, the sensor alignment is part of a state vector that includes the attitude. The alignments are adjusted along with the attitude to minimize all observation residuals. It is shown that the latter method can result in much less alignment uncertainty when gyroscopes are used for attitude propagation during the alignment estimation. The additional information for this increased accuracy comes from knowledge of relative attitude obtained from the spacecraft gyroscopes. The theoretical calculations of this difference in accuracy are presented. Also presented are numerical estimates of the alignment uncertainties of the fixed-head star trackers on the Extreme Ultraviolet Explorer spacecraft using both methods.

Methods for estimating private forest ownership statistics: revised methods for the USDA Forest Service's National Woodland Owner Survey

Treesearch

Brenton J. ​Dickinson; Brett J. Butler

2013-01-01

The USDA Forest Service's National Woodland Owner Survey (NWOS) is conducted to better understand the attitudes and behaviors of private forest ownerships, which control more than half of US forestland. Inferences about the populations of interest should be based on theoretically sound estimation procedures. A recent review of the procedures disclosed an error in...

Controlled comparison of attitudes of psychiatrists, general practitioners, homosexual doctors and homosexual men to male homosexuality.

PubMed Central

Bhugra, D; King, M

1989-01-01

A controlled analysis of the attitudes of doctors and homosexual men to male homosexuality is reported. Not surprisingly the homosexual men held the most liberal attitudes which served as a yard-stick against which the doctors' attitudes could be assessed. The implications of these data, collected before the AIDS era, are discussed in terms of the current needs of homosexual patients. PMID:2810298

Using marketing research methods to evaluate a stage-specific intervention.

PubMed

Poscente, Neila; Rothstein, Marsha; Irvine, M Jane

2002-01-01

To show how marketing methods can be used to distribute and evaluate a health promotion intervention. Mass media promotion was used to communicate a physical activity resource. Brief telephone interviews were used to screen callers and recruit participants into a controlled trial. Follow-up was conducted 3 months later. Information was gained about the attitudes and motivation of callers. The majority of participants (study and control) made significant changes in their activity levels. The study demonstrated that even when mass media channels are used, market segmentation can be achieved and program evaluation conducted.

The effects of higher-order questioning strategies on nonscience majors' achievement in an introductory environmental science course and their attitudes toward the environment

NASA Astrophysics Data System (ADS)

Eason, Grace Teresa

The purpose of this quasi-experimental study was to determine the effect a higher-order questioning strategy (Bloom, 1956) had on undergraduate non-science majors' attitudes toward the environment and their achievement in an introductory environmental science course, EDS 1032, "Survey of Science 2: Life Science," which was offered during the Spring 2000 term. Students from both treatment and control groups (N = 63), which were determined using intact classes, participated in eight cooperative group activities based on the Biological Sciences Curriculum Studies (BSCS) 5E model (Bybee, 1993). The treatment group received a higher-order questioning method combined with the BSCS 5E model. The control group received a lower-order questioning method, combined with the BSCS 5E model. Two instruments were used to measure students' attitude and achievement changes. The Ecology Issue Attitude (EIA) survey (Schindler, 1995) and a comprehensive environmental science final exam. Kolb's Learning Style Inventory (KLSI, 1985) was used to measure students' learning style type. After a 15-week treatment period, results were analyzed using MANCOVA. The overall MANCOVA model used to test the statistical difference between the collective influences of the independent variables on the three dependent variables simultaneously was found to be not significant at alpha = .05. This differs from findings of previous studies in which higher-order questioning techniques had a significant effect on student achievement (King 1989 & 1992; Blosser, 1991; Redfield and Rousseau, 1981; Gall 1970). At the risk of inflated Type I and Type II error rates, separate univariate analyses were performed. However, none of the research factors, when examined collectively or separately, made any significant contribution to explaining the variability in EIA attitude, EIA achievement, and comprehensive environmental science final examination scores. Nevertheless, anecdotal evidence from student's self-reported behavior changes indicated favorable responses to an increased awareness of and positive action toward the environment.

Farmers Knowledge, Attitudes, Practices and Health Problems Associated with Pesticide Use in Rural Irrigation Villages, Southwest Ethiopia.

PubMed

Gesesew, Hailay Abrha; Woldemichael, Kifle; Massa, Desalegn; Mwanri, Lillian

2016-01-01

In Ethiopia, pesticides are widely used for a variety of purposes. The occurrence of contamination and poisoning for farmers is highly reported due to unsafe handling practices and their usage. We assessed knowledge, attitudes and experiences of previous pesticide exposure, and related health problems among farmers who use irrigation in Jimma Zone, Southwest Ethiopia. A community based cross-sectional study was conducted among farmers living in the zone. Respondents were 796 irrigation farmers from 20 kebeles (lowest administration unit) in Jimma Zone. Data were collected using a pretested and structured questionnaire via face-to-face interviews. Both descriptive and inferential statistics analysis were performed. A binary logistic regression was used to identify factors associated with attitudes of farmers towards the safe use of pesticides at P value of ≤ 0.05 in the final model. Among the participants, 54.4% (95%CI, 50.7-58%) knew at least one pesticide control method and 53.7% had positive attitudes towards safe use of pesticide. The mean score of attitudes was found to be 3.9(±0.4). Knowledge including each of the following: the names of the pesticides (AOR, 0.41; 95%CI, 0.25-0.67), methods of pest control and the use of gloves during pesticide exposure (AOR, 1.52; 95%CI, 1.07-2.16) was found to be independent predictor of the farmers' attitudes about safe use of pesticides. Past exposure of pesticide was reported by 89.6% of farmers. Participants reported ingestion (88.9%) and inhalation (90.4%) as possible mechanisms of pesticide exposure. Nearly 42% of farmers had never used any personal protective equipment (PPE) to protect themselves against pesticide exposure. Farmers reported several health complications, which were perceived as complications of pesticide exposure, including: headache, nausea and vomiting, skin rash and irritation and abdominal pain. The study exposed the existence of high probability of pesticide exposure, the low safe use of pesticide and the low use of PPE. However, but farmers had positive attitudes towards safe use of pesticides. These findings appeal for the development of effective public health strategies to improve farmers' awareness and safe use of PPE. In addition, there is a need to inform farmers about integrated pest management to prevent severe health complications, which may occur as a result of unsafe and inappropriate use of pesticides.

Absolute Stability Analysis of a Phase Plane Controlled Spacecraft

NASA Technical Reports Server (NTRS)

Jang, Jiann-Woei; Plummer, Michael; Bedrossian, Nazareth; Hall, Charles; Jackson, Mark; Spanos, Pol

2010-01-01

Many aerospace attitude control systems utilize phase plane control schemes that include nonlinear elements such as dead zone and ideal relay. To evaluate phase plane control robustness, stability margin prediction methods must be developed. Absolute stability is extended to predict stability margins and to define an abort condition. A constrained optimization approach is also used to design flex filters for roll control. The design goal is to optimize vehicle tracking performance while maintaining adequate stability margins. Absolute stability is shown to provide satisfactory stability constraints for the optimization.

Feedback attitude sliding mode regulation control of spacecraft using arm motion

NASA Astrophysics Data System (ADS)

Shi, Ye; Liang, Bin; Xu, Dong; Wang, Xueqian; Xu, Wenfu

2013-09-01

The problem of spacecraft attitude regulation based on the reaction of arm motion has attracted extensive attentions from both engineering and academic fields. Most of the solutions of the manipulator’s motion tracking problem just achieve asymptotical stabilization performance, so that these controllers cannot realize precise attitude regulation because of the existence of non-holonomic constraints. Thus, sliding mode control algorithms are adopted to stabilize the tracking error with zero transient process. Due to the switching effects of the variable structure controller, once the tracking error reaches the designed hyper-plane, it will be restricted to this plane permanently even with the existence of external disturbances. Thus, precise attitude regulation can be achieved. Furthermore, taking the non-zero initial tracking errors and chattering phenomenon into consideration, saturation functions are used to replace sign functions to smooth the control torques. The relations between the upper bounds of tracking errors and the controller parameters are derived to reveal physical characteristic of the controller. Mathematical models of free-floating space manipulator are established and simulations are conducted in the end. The results show that the spacecraft’s attitude can be regulated to the position as desired by using the proposed algorithm, the steady state error is 0.000 2 rad. In addition, the joint tracking trajectory is smooth, the joint tracking errors converges to zero quickly with a satisfactory continuous joint control input. The proposed research provides a feasible solution for spacecraft attitude regulation by using arm motion, and improves the precision of the spacecraft attitude regulation.

Integrated Power and Attitude Control for a Spacecraft with Flywheels and Control Moment Gyroscopes

NASA Technical Reports Server (NTRS)

Roithmayr, Carlos M.; Karlgaard, Christopher D.; Kumar, Renjith R.; Bose, David M.

2003-01-01

A law is designed for simultaneous control of the orientation of an Earth-pointing spacecraft, the energy stored by counter-rotating flywheels, and the angular momentum of the flywheels and control moment gyroscopes used together as all integrated set of actuators for attitude control. General. nonlinear equations of motion are presented in vector-dyadic form, and used to obtain approximate expressions which are then linearized in preparation for design of control laws that include feedback of flywheel kinetic energy error as it means of compensating for damping exerted by rotor bearings. Two flywheel 'steering laws' are developed such that torque commanded by all attitude control law is achieved while energy is stored or discharged at the required rate. Using the International Space Station as an example, numerical simulations are performed to demonstrate control about a torque equilibrium attitude and illustrate the benefits of kinetic energy error feedback.

Modelling and simulation of Space Station Freedom berthing dynamics and control

NASA Technical Reports Server (NTRS)

Cooper, Paul A.; Garrison, James L., Jr.; Montgomery, Raymond C.; Wu, Shih-Chin; Stockwell, Alan E.; Demeo, Martha E.

1994-01-01

A large-angle, flexible, multibody, dynamic modeling capability has been developed to help validate numerical simulations of the dynamic motion and control forces which occur during berthing of Space Station Freedom to the Shuttle Orbiter in the early assembly flights. This paper outlines the dynamics and control of the station, the attached Shuttle Remote Manipulator System, and the orbiter. The simulation tool developed for the analysis is described and the results of two simulations are presented. The first is a simulated maneuver from a gravity-gradient attitude to a torque equilibrium attitude using the station reaction control jets. The second simulation is the berthing of the station to the orbiter with the station control moment gyros actively maintaining an estimated torque equilibrium attitude. The influence of the elastic dynamic behavior of the station and of the Remote Manipulator System on the attitude control of the station/orbiter system during each maneuver was investigated. The flexibility of the station and the arm were found to have only a minor influence on the attitude control of the system during the maneuvers.

Affectionless control by the same-sex parents increases dysfunctional attitudes about achievement.

PubMed

Otani, Koichi; Suzuki, Akihito; Matsumoto, Yoshihiko; Sadahiro, Ryoichi; Enokido, Masanori

2014-08-01

The affectionless control parenting has been associated with depression in recipients. The aim of this study was to examine the effect of this parenting style on dysfunctional attitudes predisposing to depression. The subjects were 666 Japanese volunteers. Perceived parental rearing was evaluated by the Parental Bonding Instrument, which has the care and protection subscales. Parental rearing was classified into four types, i.e., optimal parenting (high care/low protection), affectionate constraint (high care/high protection), neglectful parenting (low care/low protection), and affectionless control (low care/high protection). Dysfunctional attitudes were evaluated by the 24-item Dysfunctional Attitude Scale, which has the achievement, dependency and self-control subscales. Males with paternal affectionless control had higher achievement scores than those with paternal optimal parenting (P=.016). Similarly, females with maternal affectionless control had higher achievement scores than those with maternal optimal parenting (P=.016). The present study suggests that affectionless control by the same-sex parents increases dysfunctional attitudes about achievement. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Magnetic attitude control torque generation of a gravity gradient stabilized satellite

NASA Astrophysics Data System (ADS)

Suhadis, N. M.; Salleh, M. B.; Rajendran, P.

2018-05-01

Magnetic torquer is used to generate a magnetic dipole moment onboard satellites whereby a control torque for attitude control purposes is generated when it couples with the geomagnetic field. This technique has been considered very attractive for satellites operated in Low Earth Orbit (LEO) as the strength of the geomagnetic field is relatively high below the altitude of 1000 km. This paper presents the algorithm used to generate required magnetic dipole moment by 3 magnetic torquers mounted onboard a gravity gradient stabilized satellite operated at an altitude of 540 km with nadir pointing mission. As the geomagnetic field cannot be altered and its magnitude and direction vary with respect to the orbit altitude and inclination, a comparison study of attitude control torque generation performance with various orbit inclination is performed where the structured control algorithm is simulated for 13°, 33° and 53° orbit inclinations to see how the variation of the satellite orbit affects the satellite's attitude control torque generation. Results from simulation show that the higher orbit inclination generates optimum magnetic attitude control torque for accurate nadir pointing mission.

Attitude towards littering as a mediator of the relationship between personality attributes and responsible environmental behavior

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ojedokun, Oluyinka, E-mail: yinkaoje2004@yahoo.com

Highlights: > Independently, altruism and locus of control contributed significantly toward attitude towards littering. > Altruism and locus of control jointly contributed significantly to attitude towards littering. > The results further show a significant joint influence of altruism and locus of control on REB. > The independent contributions reveal that altruism and locus of control contribute significantly to REB. > Attitude towards littering mediates the relationship between locus of control and REB. - Abstract: The study tested whether attitude towards littering mediates the relationship between personality attributes (altruism and locus of control) and responsible environmental behavior (REB) among some residentsmore » of Ibadan metropolis, Nigeria. Using multistage sampling technique, measures of each construct were administered to 1360 participants. Results reveal significant independent and joint influence of personality attributes on attitude towards littering and responsible environmental behavior, respectively. Attitude towards littering also mediates the relationship between personality characteristics and REB. These findings imply that individuals who possess certain desirable personality characteristics and who have unfavorable attitude towards littering have more tendencies to engage in pro-environmental behavior. Therefore, stakeholders who have waste management as their priority should incorporate this information when guidelines for public education and litter prevention programs are being developed. It is suggested that psychologists should be involved in designing of litter prevention strategies. This will ensure the inclusion of behavioral issues in such strategies. An integrated approach to litter prevention that combines empowerment, cognitive, social, and technical solutions is recommended as the most effective tool of tackling the litter problem among residents of Ibadan metropolis.« less

Nurses' Own Birth Experiences Influence Labor Support Attitudes and Behaviors.

PubMed

Aschenbrenner, Ann P; Hanson, Lisa; Johnson, Teresa S; Kelber, Sheryl T

2016-01-01

To describe the attitudes of intrapartum nurses about the importance of and intent to provide professional labor support (PLS); barriers to PLS, such as perceived subjective norms and perceived behavioral control; and relationships among attitudes, behaviors, and nurse and site characteristics. A cross-sectional, mixed-methods, descriptive design was guided by the Theory of Planned Behavior. Three hospital sites in one region of a single Midwestern state. Sixty intrapartum nurses participated. The Labor Support Questionnaire and demographic questionnaire were administered online. The Labor Support Questionnaire is used to measure attitudes about the importance of and intended behaviors associated with labor support. Nurse Caring Behaviors was the highest rated PLS dimension. Participants' own personal birth experiences and length of current intrapartum experience were positively correlated with attitudes about and intent to provide PLS. Barriers to PLS included staffing, documentation, physicians, use of epidural analgesia, doulas, and birth plans. Personal birth and work experience influenced attitudes about and intent to provide PLS and demonstrated the relationships described in the Theory of Planned Behavior. Intrapartum nurses may benefit from an examination of their personal experiences to see how they might influence attitudes about PLS. Enhanced training and expanded labor and birth experience for novice nurses or students may improve attitudes and intended behavior with regard to PLS. Further investigations of the factors that affect integration of PLS into care are important to promote healthy birth outcomes. Copyright © 2016 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses. Published by Elsevier Inc. All rights reserved.

The impact of an environmental health education intervention on the knowledge and attitudes of students of public health graduate programs

NASA Astrophysics Data System (ADS)

Negron Martinez, Edna L.

The principal aim of this study is to ascertain any changes, if any, in the level of environmental knowledge and attitudes among graduate students, after being exposed to a Core Course in Public Health that included Environmental Health topics, as compared with a group of students that did not take courses in said field. The investigation followed a quasi-experimental design. A questionnaire derived from, The Survey of Environmental Issue Attitudes and The New Environmental Paradigm Growth and Technology Scale, was distributed through a pre- and post-test method. The total sample consisted of 75 students of Graduate Programs in the University of Puerto Rico. Forty-one students (experimental group) were selected at random, while 34 students (control group) were chosen by availability. The results of this study showed that the education pursued in the field of Environmental Health had no significant effects on students, as to any changes in their attitudes toward the environment, as compared with the control group. Forty-nine of the students, that is, 65%, showed attitudes corresponding to a level of neutrality, which usually leads to egocentric attitudes. Significant differences were demonstrated, on a scale from 1 to 100, regarding the relative importance given to several issues, 8.82 points were scored for the topic of population control, 15.16 for the subject of water quality improvement, 14.59 for the deterring of global warming, and 13.97 for the improvement of air quality. As to the measurement of ecocentric attitudes there was a significant difference, p < .05, in the average scoring obtained by females, who scored 30.7 points, and males, who scored 27.6 points. These results showed a more marked tendency towards egocentric attitudes among males. The average scoring on knowledge (1--10 scale) among male students (6.4) was higher in comparison with that of female students (5.4). Forty-eight participants, which was the majority (66.6%), indicated (during the pre-test) that they have been informed about environmental topics, through what they watch on television. One of the implications of this study is that the impact of environmental education on the learning-teaching processes, at the undergraduate and graduate level, must be reevaluated by academic institutions

Multiple Model Adaptive Attitude Control of LEO Satellite with Angular Velocity Constraints

NASA Astrophysics Data System (ADS)

Shahrooei, Abolfazl; Kazemi, Mohammad Hosein

2018-04-01

In this paper, the multiple model adaptive control is utilized to improve the transient response of attitude control system for a rigid spacecraft. An adaptive output feedback control law is proposed for attitude control under angular velocity constraints and its almost global asymptotic stability is proved. The multiple model adaptive control approach is employed to counteract large uncertainty in parameter space of the inertia matrix. The nonlinear dynamics of a low earth orbit satellite is simulated and the proposed control algorithm is implemented. The reported results show the effectiveness of the suggested scheme.

Space station systems technology study (add-on task). Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1985-01-01

System concepts were characterized in order to define cost versus benefits for autonomous functional control and for controls and displays for OMV, OTV, and spacecraft servicing and operation. The attitude control topic focused on characterizing the Space Station attitude control problem through simulation of control system responses to structural disturbances. The first two topics, mentioned above, focused on specific technology items that require advancement in order to support an early 1990s initial launch of a Space Station, while the attitude control study was an exploration of the capability of conventional controller techniques.

Simulation of spacecraft attitude dynamics using TREETOPS and model-specific computer Codes

NASA Technical Reports Server (NTRS)

Cochran, John E.; No, T. S.; Fitz-Coy, Norman G.

1989-01-01

The simulation of spacecraft attitude dynamics and control using the generic, multi-body code called TREETOPS and other codes written especially to simulate particular systems is discussed. Differences in the methods used to derive equations of motion--Kane's method for TREETOPS and the Lagrangian and Newton-Euler methods, respectively, for the other two codes--are considered. Simulation results from the TREETOPS code are compared with those from the other two codes for two example systems. One system is a chain of rigid bodies; the other consists of two rigid bodies attached to a flexible base body. Since the computer codes were developed independently, consistent results serve as a verification of the correctness of all the programs. Differences in the results are discussed. Results for the two-rigid-body, one-flexible-body system are useful also as information on multi-body, flexible, pointing payload dynamics.

Numerical analysis of orbital transfers to Mars using solar sails and attitude control

NASA Astrophysics Data System (ADS)

Pereira, M. C.; de Melo, C. F.; Meireles, L. G.

2017-10-01

Solar sails present a promising alternative method of propulsion for the coming phases of the space exploration. With the recent advances in materials engineering, the construction of lighter and more resistant materials capable of impelling spaceships with the use of solar radiation pressure has become increasingly viable technologically and economically. The studies, simulations and analysis of orbital transfers from Earth to Mars proposed in this work were implemented considering the use of a flat solar sail. Maneuvers considering the delivery of a sailcraft from a Low Earth Orbit to the border of the Earth’s sphere of influence and interplanetary trajectories to Mars were investigated. A set of simulations were implemented varying the attitude of the sail relative to the Sun. Results show that a sailcraft can carry out transfers with final velocity with respect to Mars smaller than the interplanetary Patched-conic approximation, although this requires a longer time of transfers, provided the attitude of the sailcraft relative to the Sun can be controlled in some points of the trajectories.

A Flight Control Approach for Small Reentry Vehicles

NASA Technical Reports Server (NTRS)

Bevacqoa, Tim; Adams, Tony; Zhu. J. Jim; Rao, P. Prabhakara

2004-01-01

Flight control of small crew return vehicles during atmospheric reentry will be an important technology in any human space flight mission undertaken in the future. The control system presented in this paper is applicable to small crew return vehicles in which reaction control system (RCS) thrusters are the only actuators available for attitude control. The control system consists of two modules: (i) the attitude controller using the trajectory linearization control (TLC) technique, and (ii) the reaction control system (RCS) control allocation module using a dynamic table-lookup technique. This paper describes the design and implementation of the TLC attitude control and the dynamic table-lookup RCS control allocation for nonimal flight along with design verification test results.

Mariner Mars 1971 attitude control subsystem flight performance

NASA Technical Reports Server (NTRS)

Schumacher, L.

1973-01-01

The flight performance of the Mariner 71 attitude control subsystem is discussed. Each phase of the mission is delineated and the attitude control subsystem is evaluated within the observed operational environment. Performance anomalies are introduced and discussed within the context of general performance. Problems such as the sun sensor interface incompatibility, gas valve leaks, and scan platform dynamic coupling effects are given analytical considerations.

Using movies to teach professionalism to medical students

PubMed Central

2011-01-01

Background Professionalism topics are usually not covered as a separate lesson within formal curriculum, but in subtler and less officially recognized educational activities, which makes them difficult to teach and assess. Interactive methods (e.g. movies) could be efficient teaching methods but are rarely studied. The aims of this study were: 1) to test the relevance and usefulness of movies in teaching professionalism to fourth year medical students and, 2) to assess the impact of this teaching method on students' attitudes towards some professionalism topics. Method This was an education study with qualitative data analysis in a group of eleven fourth year medical students from the Medical School of University Maribor who attended an elective four month course on professionalism. There were 8 (66.7%) female students in the group. The mean age of the students was 21.9 ± 0.9 years. The authors used students' written reports and oral presentations as the basis for qualitative analysis using thematic codes. Results Students recognised the following dimensions in the movie: communication, empathy, doctors' personal interests and palliative care. It also made them think about their attitudes towards life, death and dying. Conclusions The controlled environment of movies successfully enables students to explore their values, beliefs, and attitudes towards features of professionalism without feeling that their personal integrity had been threatened. Interactive teaching methods could become an indispensible aid in teaching professionalism to new generations. PMID:21861900

Rationale, design and methods for a staggered-entry, waitlist controlled clinical trial of the impact of a community-based, family-centred, multidisciplinary program focussed on activity, food and attitude habits (Curtin University's Activity, Food and Attitudes Program--CAFAP) among overweight adolescents.

PubMed

Straker, Leon M; Smith, Kyla L; Fenner, Ashley A; Kerr, Deborah A; McManus, Alexandra; Davis, Melissa C; Fielding, Angela M; Olds, Tim S; Hagger, Martin S; Smith, Anne J; Abbott, Rebecca A

2012-06-21

Current estimates place just under one quarter of adolescents in Australia as overweight or obese. Adolescence has been identified as a critical period for the development of obesity, yet despite this recognition, there is limited systematic research into or evaluation of interventions for overweight adolescents. Reviews have concluded that there is a substantive evidence gap for effective intervention, but physical activity, lifestyle change and family involvement have been identified as promising foci for treatment. This paper reports on the development of a staggered-entry, waitlist controlled clinical trial to assess the impact of a multidisciplinary intervention aiming to change the poor health trajectory of overweight adolescents and help them avoid morbid obesity in adulthood-Curtin University's Activity, Food and Attitudes Program (CAFAP). 96 adolescents, aged 11-16 years, and parents, will attend twice weekly during an 8 week intensive multidisciplinary program with maintenance follow-up focussed on improving activity, food and attitude habits. Follow-up assessments will be conducted immediately after completing the intensive program, and at 3, 6 and 12 months post intensive program. Main outcomes will be objectively-measured physical activity, sedentary behaviour and activity behaviours; food intake (measured by 3 day diary) and food behaviours; body composition, fitness and physical function; mental and social well-being (quality of life, mood and attitudes), and family functioning. This trial will provide important information to understand whether a community based multidisciplinary intervention can have short and medium term effects on activity and food habits, attitudes, and physical and mental health status of overweight adolescents. Australian New Zealand Clinical Trials Registry ACTRN12611001187932.

A direct application of the non-linear inverse transformation flight control system design on a STOVL aircraft

NASA Technical Reports Server (NTRS)

Chung, W. W.; Mcneill, W. E.; Stortz, M. W.

1993-01-01

The nonlinear inverse transformation flight control system design method is applied to the Lockheed Ft. Worth Company's E-7D short takeoff and vertical land (STOVL) supersonic fighter/attack aircraft design with a modified General Electric F110 engine which has augmented propulsive lift capability. The system is fully augmented to provide flight path control and velocity control, and rate command attitude hold for angular axes during the transition and hover operations. In cruise mode, the flight control system is configured to provide direct thrust command, rate command attitude hold for pitch and roll axes, and sideslip command with turn coordination. A control selector based on the nonlinear inverse transformation method is designed specifically to be compatible with the propulsion system's physical configuration which has a two dimensional convergent-divergent aft nozzle, a vectorable ventral nozzle, and a thrust augmented ejector. The nonlinear inverse transformation is used to determine the propulsive forces and nozzle deflections, which in combination with the aerodynamic forces and moments (including propulsive induced contributions), and gravitational force, are required to achieve the longitudinal and vertical acceleration commands. The longitudinal control axes are fully decoupled within the propulsion system's performance envelope. A piloted motion-base flight simulation was conducted on the Vertical Motion Simulator (VMS) at NASA Ames Research Center to examine the handling qualities of this design. Based on results of the simulation, refinements to the control system have been made and will also be covered in the report.

Flex Dynamics Avoidance Control of the NEA Scout Solar Sail Spacecraft's Reaction Control System

NASA Technical Reports Server (NTRS)

Heaton Andrew; Stiltner, Brandon; Diedrich, Benjamin; Becker, Christopher; Orphee, Juan

2017-01-01

The Attitude Control System (ACS) is developed for a Near Earth Asteroid (NEA) Scout mission using a solar sail. The NEA-Scout spacecraft is a 6U cubesat with an 86 square-meter solar sail. NEA Scout will launch on Space Launch System (SLS) Exploration Mission 1 (EM-1), currently scheduled to launch in 2018. The spacecraft will rendezvous with a target asteroid after a two year journey, and will conduct science imagery. The solar sail spacecraft ACS consists of three major actuating subsystems: a Reaction Wheel (RW) control system, a Reaction Control System (RCS), and an Adjustable Mass Translator (AMT) system. The three subsystems allow for a wide range of spacecraft attitude control capabilities, needed for the different phases of the NEA-Scout mission. Because the sail is a flexible structure, care must be taken in designing a control system to avoid exciting the structural modes of the sail. This is especially true for the RCS, which uses pulse actuated, cold-gas jets to control the spacecraft's attitude. While the reaction wheels can be commanded smoothly, the RCS jets are simple on-off actuators. Long duration firing of the RCS jets - firings greater than one second - can be thought of as step inputs to the spacecraft's torque. On the other hand, short duration firings - pulses on the order of 0.1 seconds - can be thought of as impulses in the spacecraft's torque. These types of inputs will excite the structural modes of the spacecraft, causing the sail to oscillate. Sail oscillations are undesirable for many reasons. Mainly, these oscillations will feed into the spacecraft attitude sensors and pointing accuracy, and long term oscillations may be undesirable over the lifetime of the solar sail. In order to limit the sail oscillations, an RCS control scheme is being developed to minimize sail excitations. Specifically, an input shaping scheme similar to the method described in Reference 1 will be employed. A detailed description of the RCS control scheme will be provided with particular emphasis on flexible body excitation. The RCS performance will be provided to show that sail and boom excitation is minimized.

Variation in Sexual Behaviors in a Cohort of Adolescent Females: The Role of Personal, Perceived Peer and Family Attitudes

PubMed Central

Gold, Melanie A.; Bost, James E.; Adimora, Ada A.; Orr, Donald P.; Fortenberry, J. Dennis

2010-01-01

Purpose Little is known about how adolescent sexual behaviors develop and the influence of personal or perceived social attitudes. We sought to describe how personal, perceived peer and perceived family attitudes towards adolescent sexual activity influences adolescent females’ sexual behaviors over time. Methods Between 1999–2006, 358 English-speaking females, aged 14–17 were recruited from three urban adolescent clinics. Participants completed quarterly and annual questionnaires over 4 years. Primary outcomes were engagement in eight sexual behaviors: kissing, having breasts or genitals touched, touching partners’ genitals, and oral (giving or receiving), anal, or vaginal sex. Three attitudinal scales assessed personal importance of abstinence, perceived peer beliefs about when to have sex and perceived family beliefs that adolescent sex is negative.. We used generalized estimating equations to identify predictors of each sexual behavior and compared whether personal, perceived peer or perceived family attitudes predicted sexual behaviors over time. Results The odds of reporting each sexual behavior increased with age but were lower among those whose personal or perceived family attitudes were less positive. Participants’ personal attitudes towards adolescent sex were the strongest predictor of engagement in all eight sexual behaviors even after controlling for perceived peer and perceived family attitudes. Conclusions Female adolescent’s personal attitudes towards abstinence appear to be the strongest predictor of engagement in a variety of sexual behaviors. Efforts to influence adolescent attitudes towards abstinence may be an important approach to reducing sexual behaviors that increase the risk for pregnancy and sexually transmitted infections. PMID:21185529

Knowledge, Attitudes, and Behavior in Avoiding Secondhand Smoke Exposure Among Non-Smoking Employed Women with Higher Education in Jordan

PubMed Central

Gharaibeh, Huda; Haddad, Linda; Alzyoud, Sukaina; El-Shahawy, Omar; Baker, Nesrin Abu; Umlauf, Mary

2011-01-01

Secondhand smoke (SHS) exposure is a serious public health threat worldwide; in the developing world there are less serious efforts towards controlling women’s and children’s exposure to SHS. Knowledge, attitudes and avoidance practices among Jordanian women have never been thoroughly studied. The purpose of this study was to assess the knowledge, attitudes, and avoidance behavior towards SHS exposure among employed Jordanian women with higher education. Methods A survey was conducted among employed Jordanian women at two universities. A total of 209 women were included in the analysis. Two questionnaires regarding SHS exposure were used to measure knowledge, attitudes and avoidance practices. Results Most respondents were regularly exposed to SHS in various locations during daily life, even though they were very knowledgeable about the dangers of SHS exposure for women and children. However, the subject’s attitudes and avoidance behavior did not reflect the level of knowledge about SHS risks. The results suggests there is a large discrepancy between SHS exposure, knowledge, attitudes and avoidance behavior among highly educated Jordanian women that is likely influenced by culture and traditional gender roles. Public health initiatives are needed in Jordan to address public policy, institutional practices and to empowerment of women to reduce SHS exposure. PMID:22163203

A data reduction technique and associated computer program for obtaining vehicle attitudes with a single onboard camera

NASA Technical Reports Server (NTRS)

Bendura, R. J.; Renfroe, P. G.

1974-01-01

A detailed discussion of the application of a previously method to determine vehicle flight attitude using a single camera onboard the vehicle is presented with emphasis on the digital computer program format and data reduction techniques. Application requirements include film and earth-related coordinates of at least two landmarks (or features), location of the flight vehicle with respect to the earth, and camera characteristics. Included in this report are a detailed discussion of the program input and output format, a computer program listing, a discussion of modifications made to the initial method, a step-by-step basic data reduction procedure, and several example applications. The computer program is written in FORTRAN 4 language for the Control Data 6000 series digital computer.

Casual hook up sex during the first year of college: Prospective associations with attitudes about sex and love relationships.

PubMed

Katz, Jennifer; Schneider, Monica E

2013-11-01

This study examined bidirectional relationships among emerging adults' involvement in casual hook up sex and attitudes about sex and love relationships. At the start and end of their first year in college, undergraduates (N = 163) responded to measures of sexual behavior, sexual attitudes, and attitudes about love relationships. In cross-sectional analyses, attitudes about sex and love both were associated with involvement in casual hook up sex. In prospective analyses, initial attitudes about sexual instrumentality uniquely predicted involvement in later hook up sex, even after controlling for past hook up sex. Furthermore, involvement in hook up sex during the first year of college predicted greater sexual permissiveness and comfort with casual genital contact, even after controlling for initial sexual attitudes and hook up behaviors. None of the associations between attitudes and behavior were qualified by gender. Experiences of causal hook up sex appear to have implications primarily for emerging adults' attitudes about sexual interactions rather than their attitudes about love relationships.

Using the implicit relational assessment procedure to compare implicit pro-thin/anti-fat attitudes of patients with anorexia nervosa and non-clinical controls.

PubMed

Parling, Thomas; Cernvall, Martin; Stewart, Ian; Barnes-Holmes, Dermot; Ghaderi, Ata

2012-01-01

Implicit pro-thin/anti-fat attitudes were investigated among a mixed group of patients with full and sub-threshold Anorexia Nervosa (n = 17), and a matched-age control group (n = 17). The Implicit Relational Assessment Procedure (IRAP) was employed to measure implicit pro-thin and anti-fat attitudes towards Self and Others in addition to "striving for thinness" and "avoidance of fatness." The clinical group showed an implicit pro-fat attitude towards Others and stronger anti-fat attitudes towards Self and avoidance of fatness compared with controls. The findings are discussed in relation to the over-evaluation of weight and shape in the clinical group.

Nudging Resisters Toward Change: Self-Persuasion Interventions for Reducing Attitude Certainty.

PubMed

Greenberg, Spencer; Brand, Danielle; Pluta, Aislinn; Moore, Douglas; DeConti, Kirsten

2018-05-01

To identify effective self-persuasion protocols that could easily be adapted to face-to-face clinical sessions or health-related computer applications as a first step in breaking patient resistance. Two self-persuasion interventions were tested against 2 controls in a between-subject randomized control experiment. GuidedTrack-a web-based platform for social science experiments. Six hundred seventeen adult participants recruited via Mechanical Turk. The experimental interventions prompted participants for self-referenced pro- and counterattitudinal arguments to elicit attitude-related thought (ART) and subsequent doubt about the attitude. The hypothesis was that the self-persuasion interventions would elicit larger and more frequent attitude certainty decreases than the controls. In the experimental groups, we also predicted a correlation between the amount of ART and attitude certainty decreases. Changes in attitude certainty were measured by participants' pre- and post-ratio scale ratings; ART was measured by the number of words participants used to respond to the interventions. Analysis of variance (ANOVA), χ 2 , and correlation. A goodness-of-fit χ 2 showed that the number of participants who decreased their attitude certainty was not equally distributed between the combined experimental groups (n = 104) and the combined control groups (n = 39), χ 2 (1, n = 143) = 28.64, P < .001. Within each intervention, goodness-of-fit χ 2 with a Bonferroni correction ( P = .01 or .05/4) indicated there were significantly more "decreasers" than "increasers" in intervention 1, χ 2 (1, n = 86) = 6.16, P = .01, but not intervention 2, χ 2 (1, n = 84) = 2.02, P = .16, the nonsense control, χ 2 (1, n = 42) = .22, P = .64), or the distraction control, χ 2 (1, n = 34) = .02, P = .89. A 1-way ANOVA revealed a significant main effect for intervention on mean certainty change ( F 3,613 = 4.62, P = .003). Five post hoc comparisons using Tukey's honest significant difference (HSD) test indicated that the mean decrease in attitude certainty resulting from intervention 1 (M = -3.29) was significantly larger than the mean decrease in attitude certainty resulting from the nonsense control (M = -0.62, t = -2.72, P = .03), the distraction control (M = 0.11, t = 3.48, P = .003), but not intervention 2 (M = -0.87, t = -2.54, P = .06). Attitude-related thought was significantly correlated with attitude certainty change in intervention 1, r(158) = -.17, t = -4.28, P = .02, but not intervention 2, r(161) = -.002, t = -.03, P = .98. The implication for clinical practitioners and designers of health applications is that it may be worthwhile to let patients elaborate on their personal reasons for initially forming an unhealthy attitude to increase doubt about the strongly held attitude.

Attitude determination and parameter estimation using vector observations - Theory

NASA Technical Reports Server (NTRS)

Markley, F. Landis

1989-01-01

Procedures for attitude determination based on Wahba's loss function are generalized to include the estimation of parameters other than the attitude, such as sensor biases. Optimization with respect to the attitude is carried out using the q-method, which does not require an a priori estimate of the attitude. Optimization with respect to the other parameters employs an iterative approach, which does require an a priori estimate of these parameters. Conventional state estimation methods require a priori estimates of both the parameters and the attitude, while the algorithm presented in this paper always computes the exact optimal attitude for given values of the parameters. Expressions for the covariance of the attitude and parameter estimates are derived.

Gun Attitudes and Fear of Crime.

ERIC Educational Resources Information Center

Heath, Linda; Weeks, Kyle; Murphy, Marie Mackay

1997-01-01

Using three studies, examined the relationship between attitudes toward guns and fear of crime. Findings indicate a connection between fear of crime and attitudes toward guns: people higher in fear of crime favored gun control. Results also established a relationship between stereotypical beliefs about gun victims and support for gun control. (RJM)

Dengue knowledge, attitudes and practices and their impact on community-based vector control in rural Cambodia

PubMed Central

Doum, Dyna; Keo, Vanney; Sokha, Ly; Sam, BunLeng; Chan, Vibol; Alexander, Neal; Bradley, John; Liverani, Marco; Prasetyo, Didot Budi; Rachmat, Agus; Lopes, Sergio; Hii, Jeffrey; Rithea, Leang; Shafique, Muhammad; Hustedt, John

2018-01-01

Background Globally there are an estimated 390 million dengue infections per year, of which 96 million are clinically apparent. In Cambodia, estimates suggest as many as 185,850 cases annually. The World Health Organization global strategy for dengue prevention aims to reduce mortality rates by 50% and morbidity by 25% by 2020. The adoption of integrated vector management approach using community-based methods tailored to the local context is one of the recommended strategies to achieve these objectives. Understanding local knowledge, attitudes and practices is therefore essential to designing suitable strategies to fit each local context. Methods and findings A Knowledge, Attitudes and Practices survey in 600 randomly chosen households was administered in 30 villages in Kampong Cham which is one of the most populated provinces of Cambodia. KAP surveys were administered to a sub-sample of households where an entomology survey was conducted (1200 households), during which Aedes larval/pupae and adult female Aedes mosquito densities were recorded. Participants had high levels of knowledge regarding the transmission of dengue, Aedes breeding, and biting prevention methods; the majority of participants believed they were at risk and that dengue transmission is preventable. However, self-reported vector control practices did not match observed practices recorded in our surveys. No correlation was found between knowledge and observed practices either. Conclusion An education campaign regarding dengue prevention in this setting with high knowledge levels is unlikely to have any significant effect on practices unless it is incorporated in a more comprehensive strategy for behavioural change, such a COMBI method, which includes behavioural models as well as communication and marketing theory and practice. Trial registration ISRCTN85307778. PMID:29451879

Improving Ebola infection prevention and control in primary healthcare facilities in Sierra Leone: a single-group pretest post-test, mixed-methods study.

PubMed

Ratnayake, Ruwan; Ho, Lara S; Ansumana, Rashid; Brown, Hannah; Borchert, Matthias; Miller, Laura; Kratz, Thomas; McMahon, Shannon A; Sahr, Foday

2016-01-01

Accomplishing infection prevention and control (IPC) in health facilities in Sub-Saharan Africa is challenging. Owing to poor IPC, healthcare workers (HCWs) were frequently infected during Sierra Leone's Ebola epidemic. In late 2014, IPC was rapidly and nationally scaled up. We carried out workshops in sampled facilities to further improve adherence to IPC. We investigated HCW experiences and observed practice gaps, before and after the workshops. We conducted an uncontrolled, before and after, mixed-methods study in eight health facilities in Bo and Kenema Districts during December 2014 and January 2015. Quantitative methods administered to HCWs at baseline and follow-up included a survey on attitudes and self-efficacy towards IPC, and structured observations of behaviours. The intervention involved a workshop for HCWs to develop improvement plans for their facility. We analysed the changes between rounds in survey responses and behaviours. We used interviews to explore attitudes and self-efficacy throughout the study period. HCWs described IPC as 'life-saving' and personal protective equipment (PPE) as uncomfortable for providers and frightening for patients. At baseline, self-efficacy was high (median=4/strongly agree). Responses reflecting unfavourable attitudes were low for glove use (median=1/strongly disagree, IQR, 1-2) and PPE use with ill family members (median=1, IQR, 1-2), and mixed for PPE use with ill HCWs (median=2/disagree, IQR, 1-4). Observations demonstrated consistent glove reuse and poor HCW handwashing. The maintenance of distance (RR 1.09, 95% CI 1.02 to 1.16) and patient handwashing (RR 1.19, 95% CI 1.3 to 1.25) improved to >90%. We found favourable attitudes towards IPC and gaps in practice. Risk perceptions of HCWs and tendencies to ration PPE where chronic supply chain issues normally lead to PPE stock-outs may affect practice. As Sierra Leone's Ebola Recovery Strategy aims to make all facilities IPC compliant, socio-behavioural improvements and a secure supply chain are essential.

The triviality of abortion in Greece.

PubMed

Naziri, D

1991-09-01

In Greece modern contraceptive methods are used only in a very limited manner and abortion is the primary form of birth control. There are several social and psychological issues that are considered to be responsible. A 1985 study done for the Family Planning Center of Thessaloniki found that the ratio of live births is 1.3 and the ratio of abortion is 1.8/woman. 88% of women in the study had had an abortion while practicing coitus interruptus. 90% of the women never bought condoms. In a 1989 study only 6% of women had a positive attitude about condoms. Abortion is used as the primary method of birth control regardless of a woman's socioeconomic status. Further it was found that abortion did not correlate with other modern attitudes or the emancipation of women. The decision to abort was related to difficulties and constraints inherent in bring up a child. However positive attitudes toward contraception were related to educational and occupational levels. To complicate matters the information concerning contraceptives was problematic and related to the women's own lack of initiative to find out, and a lack of correct information offered from gynecologists. A 1990 study on knowledge, attitudes, beliefs and practices in relation to HIV infection indicated that the most favored method of contraception was condoms, but 60.8% of the men reported use versus 33.7% of the women. However these figures are not very representative because the survey was given in the context of HIV prevention and no attempt was made to distinguish between regular and irregular use patterns. Abortions is not a moral issue in Greece. It was legalized in 1986 only because it came to the attention of the government that the previous prohibition was being completely ignored. Abortion is strongly affected by social and psychological factors that are complex and result from cultural view points about fertility, maternal value, and life itself that are unique to the Greek culture.

Lightweight, Miniature Inertial Measurement System

NASA Technical Reports Server (NTRS)

Tang, Liang; Crassidis, Agamemnon

2012-01-01

A miniature, lighter-weight, and highly accurate inertial navigation system (INS) is coupled with GPS receivers to provide stable and highly accurate positioning, attitude, and inertial measurements while being subjected to highly dynamic maneuvers. In contrast to conventional methods that use extensive, groundbased, real-time tracking and control units that are expensive, large, and require excessive amounts of power to operate, this method focuses on the development of an estimator that makes use of a low-cost, miniature accelerometer array fused with traditional measurement systems and GPS. Through the use of a position tracking estimation algorithm, onboard accelerometers are numerically integrated and transformed using attitude information to obtain an estimate of position in the inertial frame. Position and velocity estimates are subject to drift due to accelerometer sensor bias and high vibration over time, and so require the integration with GPS information using a Kalman filter to provide highly accurate and reliable inertial tracking estimations. The method implemented here uses the local gravitational field vector. Upon determining the location of the local gravitational field vector relative to two consecutive sensors, the orientation of the device may then be estimated, and the attitude determined. Improved attitude estimates further enhance the inertial position estimates. The device can be powered either by batteries, or by the power source onboard its target platforms. A DB9 port provides the I/O to external systems, and the device is designed to be mounted in a waterproof case for all-weather conditions.

Teaching evidence-based medicine more effectively.

PubMed

Hatmi, Zinat Nadia; Tahvildari, Sousan; Dabiran, Soheila; Soheili, Suraya; Sabouri Kashani, Ahmad; Raznahan, Maedeh

2010-01-01

Evidence-based Medicine (EBM) is becoming an integral component of graduate medical education competency and a requirement for grad medical education practice-based learning core competency. This study tries to compare the efficacy of conferences utilizing small-group discussions with the traditional conference method in enhancing EBM competency. The participants in this randomized controlled trial (RCT) were 170 members of the medical faculty who were divided into two groups of 86 (intervention) and 84 (control). Following the intervention, EBM competency was assessed by a written examination. statistical analysis made use of chi-square test, independent sample t-test and relative risks for univariate analysis. Mantel-Hanszel was used for bivariate analysis. Cox proportional hazard models were used to evaluate multivariate-adjusted associations between EBM educational intervention and EBM knowledge, attitude and skills. A new indicator of number needed to intervention (NNI) was defined and computed. The results proved conference along with small-group discussion to be a more effective teaching method with P=0.001 on knowledge, P<0.001 for attitude and skills P<0.001 in an EBM exam when compared with medical faculty members who did not participate in EBM educational intervention (n=84). Moreover, they had also increased confidence with critical appraisal skills, and searching EBM resources. Conferences followed by small-group discussions significantly enhance EBM knowledge, attitude, critical appraisal skills and literature review skills.

Development and Testing of a High-Precision Position and Attitude Measuring System for a Space Mechanism

NASA Technical Reports Server (NTRS)

Khanenya, Nikolay; Paciotti, Gabriel; Forzani, Eugenio; Blecha, Luc

2016-01-01

This paper describes a high-precision optical metrology system - a unique ground test equipment which was designed and implemented for simultaneous precise contactless measurements of 6 degrees-of-freedom (3 translational + 3 rotational) of a space mechanism end-effector [1] in a thermally controlled ISO 5 clean environment. The developed contactless method reconstructs both position and attitude of the specimen from three cross-sections measured by 2D distance sensors [2]. The cleanliness is preserved by the hermetic test chamber filled with high purity nitrogen. The specimen's temperature is controlled by the thermostat [7]. The developed method excludes errors caused by the thermal deformations and manufacturing inaccuracies of the test jig. Tests and simulations show that the measurement accuracy of an object absolute position is of 20 micron in in-plane measurement (XY) and about 50 micron out of plane (Z). The typical absolute attitude is determined with an accuracy better than 3 arcmin in rotation around X and Y and better than 10 arcmin in Z. The metrology system is able to determine relative position and movement with an accuracy one order of magnitude lower than the absolute accuracy. Typical relative displacement measurement accuracies are better than 1 micron in X and Y and about 2 micron in Z. Finally, the relative rotation can be measured with accuracy better than 20 arcsec in any direction.

Design, dynamics and control of an Adaptive Singularity-Free Control Moment Gyroscope actuator for microspacecraft Attitude Determination and Control System

NASA Astrophysics Data System (ADS)

Viswanathan, Sasi Prabhakaran

Design, dynamics, control and implementation of a novel spacecraft attitude control actuator called the "Adaptive Singularity-free Control Moment Gyroscope" (ASCMG) is presented in this dissertation. In order to construct a comprehensive attitude dynamics model of a spacecraft with internal actuators, the dynamics of a spacecraft with an ASCMG, is obtained in the framework of geometric mechanics using the principles of variational mechanics. The resulting dynamics is general and complete model, as it relaxes the simplifying assumptions made in prior literature on Control Moment Gyroscopes (CMGs) and it also addresses the adaptive parameters in the dynamics formulation. The simplifying assumptions include perfect axisymmetry of the rotor and gimbal structures, perfect alignment of the centers of mass of the gimbal and the rotor etc. These set of simplifying assumptions imposed on the design and dynamics of CMGs leads to adverse effects on their performance and results in high manufacturing cost. The dynamics so obtained shows the complex nonlinear coupling between the internal degrees of freedom associated with an ASCMG and the spacecraft bus's attitude motion. By default, the general ASCMG cluster can function as a Variable Speed Control Moment Gyroscope, and reduced to function in CMG mode by spinning the rotor at constant speed, and it is shown that even when operated in CMG mode, the cluster can be free from kinematic singularities. This dynamics model is then extended to include the effects of multiple ASCMGs placed in the spacecraft bus, and sufficient conditions for non-singular ASCMG cluster configurations are obtained to operate the cluster both in VSCMG and CMG modes. The general dynamics model of the ASCMG is then reduced to that of conventional VSCMGs and CMGs by imposing the standard set of simplifying assumptions used in prior literature. The adverse effects of the simplifying assumptions that lead to the complexities in conventional CMG design, and how they lead to CMG singularities, are described. General ideas on control of the angular momentum of the spacecraft using changes in the momentum variables of a finite number of ASCMGs, are provided. Control schemes for agile and precise attitude maneuvers using ASCMG cluster in the absence of external torques and when the total angular momentum of the spacecraft is zero, is presented for both constant speed and variable speed modes. A Geometric Variational Integrator (GVI) that preserves the geometry of the state space and the conserved norm of the total angular momentum is constructed for numerical simulation and microcontroller implementation of the control scheme. The GVI is obtained by discretizing the Lagrangian of the rnultibody systems, in which the rigid body attitude is globally represented on the Lie group of rigid body rotations. Hardware and software architecture of a novel spacecraft Attitude Determination and Control System (ADCS) based on commercial smartphones and a bare minimum hardware prototype of an ASCMG using low cost COTS components is also described. A lightweight, dynamics model-free Variational Attitude Estimator (VAE) suitable for smartphone implementation is employed for attitude determination and the attitude control is performed by ASCMG actuators. The VAE scheme presented here is implemented and validated onboard an Unmanned Aerial Vehicle (UAV) platform and the real time performance is analyzed. On-board sensing, data acquisition, data uplink/downlink, state estimation and real-time feedback control objectives can be performed using this novel spacecraft ADCS. The mechatronics realization of the attitude determination through variational attitude estimation scheme and control implementation using ASCMG actuators are presented here. Experimental results of the attitude estimation (filtering) scheme using smartphone sensors as an Inertial Measurement Unit (IMU) on the Hardware In the Loop (HIL) simulator testbed are given. These results, obtained in the Spacecraft Guidance, Navigation and Control Laboratory at New Mexico State University, demonstrate the performance of this estimation scheme with the noisy raw data from the smartphone sensors. Keywords: Spacecraft, momentum exchange devices, control moment gyroscope, variational mechanics, geometric mechanics, variational integrators, attitude determination, attitude control, ADCS, estimation, ASCMG, VSCMG, cubesat, mechatronics, smartphone, Android, MEMS sensor, embedded programming, microcontroller, brushless DC drives, HIL simulation.

Review of Research On Guidance for Recovery from Pitch Axis Upsets

NASA Technical Reports Server (NTRS)

Harrison, Stephanie J.

2016-01-01

A literature review was conducted to identify past efforts in providing control guidance for aircraft upset recovery including stall recovery. Because guidance is integrally linked to the intended function of aircraft attitude awareness and upset recognition, it is difficult, if not impossible, to consider these issues separately. This literature review covered the aspects of instrumentation and display symbologies for attitude awareness, aircraft upset recognition, upset and stall alerting, and control guidance. Many different forms of symbology have been investigated including, but not limited to, pitch scale depictions, attitude indicator icons, horizon symbology, attitude recovery arrows, and pitch trim indicators. Past research on different visual and alerting strategies that provide advisories, cautions, and warnings to pilots before entering an unusual attitude (UA) are also discussed. Finally, potential control guidance for recovery from upset or unusual attitudes, including approach-to-stall and stall conditions, are reviewed. Recommendations for future research are made.

ATTITUDES TOWARD SUICIDE: THE EFFECT OF SUICIDE DEATH IN THE FAMILY*

PubMed Central

Zhang, Jie; Jia, Cun-Xian

2011-01-01

There have been few reports on the effect of suicide death on family members’ attitudes toward suicide. In order to estimate the extent to which suicide death affects attitudes toward suicide among family members of suicides, data of 264 informants from a case-control psychological autopsy study were analyzed. The results showed that there were no significant differences in attitudes toward suicide, measured by the General Social Survey’s (GSS) four questions, between informants of suicides and informants of living controls, between family members of suicides and family members of living controls, or between family members of suicides and non-family members of suicides. Our findings did not support the hypothesis that suicide death affects the attitudes toward suicide in suicides’ family members. However, some factors were found to be related to the pro-suicide attitudes measured by the four questions included in the GSS. PMID:20397616

Using Policy-Capturing to Measure Attitudes in Organizational Diagnosis.

ERIC Educational Resources Information Center

Madden, Joseph M.

1981-01-01

Discusses an indirect method of attitude measurement, policy-capturing, that can be applied on an individual basis. In three experiments this method detected prejudicial attitudes toward females not detected with traditional methods. Can be used as a self-improvement diagnostic tool for developing awareness of behavior influences. (JAC)

Attitudes toward menstruation in females with schizophrenia or schizoaffective disorders in Taiwan.

PubMed

Liang, H-Y; Lee, L-W; Kelsen, B A; Hsu, S-C; Liu, C-Y; Chen, C-Y

2013-12-01

The aims of this cross-sectional, case-controlled, observational study were to examine attitudes toward menstruation in female patients with schizophrenia or schizoaffective disorder and in a control group, and to explore the associations between attitudes toward menstruation and psychopathology, menstrual regularity during antipsychotic treatment, and menstrual distress symptoms. Fifty-eight patients treated with anti-psychotic medications for at least the previous 6 months were placed in irregular (irregular menstrual cycle) (n = 31) and regular (regular menstrual cycle) (n = 27) groups. Sixty-two, age-matched, healthy female participants with regular menstrual cycles were enrolled as a control group. Psychopathology was assessed by psychiatrists using the Positive and Negative Syndrome Scale (PANSS). The Menstrual Attitude Questionnaire (MAQ) was used to assess attitudes toward menstruation, and symptom checklists based on the Moos Menstruation Distress Questionnaire (MMDQ) were used to assess menstrual distress symptoms. Patients with psychotic disorders (both irregular and regular groups) had more negative attitudes toward menstruation than the control group. In the Schizophrenia group, there was no association between the severity of psychotic symptoms and their influence on attitudes toward menstruation. Moreover, regular menstrual cycles during antipsychotic treatment and fewer menstrual distress symptoms were the two main predictors for more positive attitudes toward menstruation in the patient group. This is one of the first studies to explore the relationship between psychotic symptoms and attitudes toward menstruation. The findings provide more support for the assumption that attitudes toward menstruation are derived from a woman's perception of her bodily experience rather than a psychiatric disorder.

Parents Questioning Immunization: Evaluation of an Intervention

ERIC Educational Resources Information Center

Gust, Deborah A.; Kennedy, Allison; Weber, Deanne; Evans, Geoff; Kong, Yuan; Salmon, Daniel

2009-01-01

Objectives: To compare attitudes of parents who filed or considered filing an exemption to school immunization requirements and/or would not have their child immunized if it were not required by law (cases) to controls. To develop and evaluate a brochure intervention for parents considering an exemption. Methods: Interviews, focus groups, mailed…

Implicit Attitudes toward Violence among Male Perpetrators of Intimate Partner Violence: A Preliminary Investigation

ERIC Educational Resources Information Center

Eckhardt, Christopher I.; Samper, Rita; Suhr, Laura; Holtzworth-Munroe, Amy

2012-01-01

Whereas cognitive variables are hypothesized to play an important role in intimate partner violence (IPV) etiology and intervention, cognitive assessment methods have largely targeted offenders' explicit, controlled cognitive processing using paper-and-pencil questionnaires prone to social desirability biases. Using an implicit measure of…

Adaptive-gain fast super-twisting sliding mode fault tolerant control for a reusable launch vehicle in reentry phase.

PubMed

Zhang, Yao; Tang, Shengjing; Guo, Jie

2017-11-01

In this paper, a novel adaptive-gain fast super-twisting (AGFST) sliding mode attitude control synthesis is carried out for a reusable launch vehicle subject to actuator faults and unknown disturbances. According to the fast nonsingular terminal sliding mode surface (FNTSMS) and adaptive-gain fast super-twisting algorithm, an adaptive fault tolerant control law for the attitude stabilization is derived to protect against the actuator faults and unknown uncertainties. Firstly, a second-order nonlinear control-oriented model for the RLV is established by feedback linearization method. And on the basis a fast nonsingular terminal sliding mode (FNTSM) manifold is designed, which provides fast finite-time global convergence and avoids singularity problem as well as chattering phenomenon. Based on the merits of the standard super-twisting (ST) algorithm and fast reaching law with adaption, a novel adaptive-gain fast super-twisting (AGFST) algorithm is proposed for the finite-time fault tolerant attitude control problem of the RLV without any knowledge of the bounds of uncertainties and actuator faults. The important feature of the AGFST algorithm includes non-overestimating the values of the control gains and faster convergence speed than the standard ST algorithm. A formal proof of the finite-time stability of the closed-loop system is derived using the Lyapunov function technique. An estimation of the convergence time and accurate expression of convergence region are also provided. Finally, simulations are presented to illustrate the effectiveness and superiority of the proposed control scheme. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

A pilot's assessment of helicopter handling-quality factors common to both agility and instrument flying tasks

NASA Technical Reports Server (NTRS)

Gerdes, R. M.

1980-01-01

Results from a series of simulation and flight investigations undertaken to evaluate helicopter flying qualities and the effects of control system augmentation for nap-of-the-earth (NOE) agility and instrument flying tasks were analyzed to assess handling-quality factors common to both tasks. Precise attitude control was determined to be a key requirement for successful accomplishment of both tasks. Factors that degraded attitude controllability were improper levels of control sensitivity and damping and rotor-system cross-coupling due to helicopter angular rate and collective pitch input. Application of rate-command, attitude-command, and control-input decouple augmentation schemes enhanced attitude control and significantly improved handling qualities for both tasks. NOE agility and instrument flying handling-quality considerations, pilot rating philosophy, and supplemental flight evaluations are also discussed.

Solar Sail Attitude Control Performance Comparison

NASA Technical Reports Server (NTRS)

Bladt, Jeff J.; Lawrence, Dale A.

2005-01-01

Performance of two solar sail attitude control implementations is evaluated. One implementation employs four articulated reflective vanes located at the periphery of the sail assembly to generate control torque about all three axes. A second attitude control configuration uses mass on a gimbaled boom to alter the center-of-mass location relative to the center-of-pressure producing roll and pitch torque along with a pair of articulated control vanes for yaw control. Command generation algorithms employ linearized dynamics with a feedback inversion loop to map desired vehicle attitude control torque into vane and/or gimbal articulation angle commands. We investigate the impact on actuator deflection angle behavior due to variations in how the Jacobian matrix is incorporated into the feedback inversion loop. Additionally, we compare how well each implementation tracks a commanded thrust profile, which has been generated to follow an orbit trajectory from the sun-earth L1 point to a sub-L1 station.

Effects of nursing process-based simulation for maternal child emergency nursing care on knowledge, attitude, and skills in clinical nurses.

PubMed

Kim, Sunghee; Shin, Gisoo

2016-02-01

Since previous studies on simulation-based education have been focused on fundamental nursing skills for nursing students in South Korea, there is little research available that focuses on clinical nurses in simulation-based training. Further, there is a paucity of research literature related to the integration of the nursing process into simulation training particularly in the emergency nursing care of high-risk maternal and neonatal patients. The purpose of this study was to identify the effects of nursing process-based simulation on knowledge, attitudes, and skills for maternal and child emergency nursing care in clinical nurses in South Korea. Data were collected from 49 nurses, 25 in the experimental group and 24 in the control group, from August 13 to 14, 2013. This study was an equivalent control group pre- and post-test experimental design to compare the differences in knowledge, attitudes, and skills for maternal and child emergency nursing care between the experimental group and the control group. The experimental group was trained by the nursing process-based simulation training program, while the control group received traditional methods of training for maternal and child emergency nursing care. The experimental group was more likely to improve knowledge, attitudes, and skills required for clinical judgment about maternal and child emergency nursing care than the control group. Among five stages of nursing process in simulation, the experimental group was more likely to improve clinical skills required for nursing diagnosis and nursing evaluation than the control group. These results will provide valuable information on developing nursing process-based simulation training to improve clinical competency in nurses. Further research should be conducted to verify the effectiveness of nursing process-based simulation with more diverse nurse groups on more diverse subjects in the future. Copyright © 2015 Elsevier Ltd. All rights reserved.

Psychological mechanisms underlying doping attitudes in sport: motivation and moral disengagement.

PubMed

Hodge, Ken; Hargreaves, Elaine A; Gerrard, David; Lonsdale, Chris

2013-08-01

We examined whether constructs outlined in self-determination theory (Deci & Ryan, 2002), namely, autonomy-supportive and controlling motivational climates and autonomous and controlled motivation, were related to attitudes toward performance-enhancing drugs (PEDs) in sport and drug-taking susceptibility. We also investigated moral disengagement as a potential mediator. We surveyed a sample of 224 competitive athletes (59% female; M age = 20.3 years; M = 10.2 years of experience participating in their sport), including 81 elite athletes. Using structural equation modeling analyses, our hypothesis proposing positive relationships with controlling climates, controlled motivation, and PEDs attitudes and susceptibility was largely supported, whereas our hypothesis proposing negative relationships among autonomous climate, autonomous motivation, and PEDs attitudes and susceptibility was not supported. Moral disengagement was a strong predictor of positive attitudes toward PEDs, which, in turn, was a strong predictor of PEDs susceptibility. These findings are discussed from both motivational and moral disengagement viewpoints.

Adaptive control applied to Space Station attitude control system

NASA Technical Reports Server (NTRS)

Lam, Quang M.; Chipman, Richard; Hu, Tsay-Hsin G.; Holmes, Eric B.; Sunkel, John

1992-01-01

This paper presents an adaptive control approach to enhance the performance of current attitude control system used by the Space Station Freedom. The proposed control law was developed based on the direct adaptive control or model reference adaptive control scheme. Performance comparisons, subject to inertia variation, of the adaptive controller and the fixed-gain linear quadratic regulator currently implemented for the Space Station are conducted. Both the fixed-gain and the adaptive gain controllers are able to maintain the Station stability for inertia variations of up to 35 percent. However, when a 50 percent inertia variation is applied to the Station, only the adaptive controller is able to maintain the Station attitude.

Monitoring Spacecraft Telemetry Via Optical or RF Link

NASA Technical Reports Server (NTRS)

Fielhauer, K. B.; Boone, B. G.

2011-01-01

A patent disclosure document discusses a photonic method for connecting a spacecraft with a launch vehicle upper-stage telemetry system as a means for monitoring a spacecraft fs health and status during and right after separation and deployment. This method also provides an efficient opto-coupled capability for prelaunch built-in-test (BIT) on the ground to enable more efficient and timely integration, preflight checkout, and a means to obviate any local EMI (electromagnetic interference) during integration and test. Additional utility can be envisioned for BIT on other platforms, such as the International Space Station (ISS). The photonic telemetry system implements an optical free-space link with a divergent laser transmitter beam spoiled over a significant cone angle to accommodate changes in spacecraft position without having to angle track it during deployment. Since the spacecraft may lose attitude control and tumble during deployment, the transmitted laser beam interrogates any one of several low-profile meso-scale retro-reflective spatial light modulators (SLMs) deployed over the surface of the spacecraft. The return signal beam, modulated by the SLMs, contains health, status, and attitude information received back at the launch vehicle. Very compact low-power opto-coupler technology already exists for the received signal (requiring relatively low bandwidths, e.g., .200 kbps) to enable transfer to a forward pass RF relay from the launch vehicle to TDRSS (Tracking and Data Relay Satellite System) or another recipient. The link would be active during separation and post-separation to monitor spacecraft health, status, attitude, or other data inventories until attitude recovery and ground control can be re-established. An optical link would not interfere with the existing upper stage telemetry and beacon systems, thus meeting launch vehicle EMI environmental constraints.

Farmer attitudes to vaccination and culling of badgers in controlling bovine tuberculosis.

PubMed

Warren, M; Lobley, M; Winter, M

2013-07-13

Controversy persists in England, Wales and Northern Ireland concerning methods of controlling the transmission of bovine tuberculosis (bTB) between badgers and cattle. The National Trust, a major land-owning heritage organisation, in 2011, began a programme of vaccinating badgers against bTB on its Killerton Estate in Devon. Most of the estate is farmed by 18 tenant farmers, who thus have a strong interest in the Trust's approach, particularly as all have felt the effects of the disease. This article reports on a study of the attitudes to vaccination of badgers and to the alternative of a culling programme, using face-to-face interviews with 14 of the tenants. The results indicated first that the views of the respondents were more nuanced than the contemporary public debate about badger control would suggest. Secondly, the attitude of the interviewees to vaccination of badgers against bTB was generally one of resigned acceptance. Thirdly, most respondents would prefer a combination of an effective vaccination programme with an effective culling programme, the latter reducing population of density sufficiently (and preferably targeting the badgers most likely to be diseased) for vaccination to have a reasonable chance of success. While based on a small sample, these results will contribute to the vigorous debate concerning contrasting policy approaches to bTB control in England, Wales and Northern Ireland.

Gimbal-Angle Vectors of the Nonredundant CMG Cluster

NASA Astrophysics Data System (ADS)

Lee, Donghun; Bang, Hyochoong

2018-05-01

This paper deals with the method using the preferred gimbal angles of a control moment gyro (CMG) cluster for controlling spacecraft attitude. To apply the method to the nonredundant CMG cluster, analytical gimbal-angle solutions for the zero angular momentum state are derived, and the gimbal-angle vectors for the nonzero angular momentum states are studied by a numerical method. It will be shown that the number of the gimbal-angle vectors is determined from the given skew angle and the angular momentum state of the CMG cluster. Through numerical examples, it is shown that the method using the preferred gimbal-angle is an efficient approach to avoid internal singularities for the nonredundant CMG cluster.

LQG/LTR Optimal Attitude Control of Small Flexible Spacecraft Using Free-Free Boundary Conditions

DTIC Science & Technology

2006-08-03

particular on attitude control of flex- ible space structures. Croopnick et al .[50] present a literature survey in the areas of attitude control...modeling and control of space structures is compiled by Nurre et al .[161]. One important thing to note from the surveys listed above is the 21 focus on the...papers surveyed by Croopnick et al . in 1979, by Meirovitch in 1979, Balas in 1982, and Nurre et al . in 1984. The focus of the papers included in all

Error compensation of single-antenna attitude determination using GNSS for Low-dynamic applications

NASA Astrophysics Data System (ADS)

Chen, Wen; Yu, Chao; Cai, Miaomiao

2017-04-01

GNSS-based single-antenna pseudo-attitude determination method has attracted more and more attention from the field of high-dynamic navigation due to its low cost, low system complexity, and no temporal accumulated errors. Related researches indicate that this method can be an important complement or even an alternative to the traditional sensors for general accuracy requirement (such as small UAV navigation). The application of single-antenna attitude determining method to low-dynamic carrier has just started. Different from the traditional multi-antenna attitude measurement technique, the pseudo-attitude attitude determination method calculates the rotation angle of the carrier trajectory relative to the earth. Thus it inevitably contains some deviations comparing with the real attitude angle. In low-dynamic application, these deviations are particularly noticeable, which may not be ignored. The causes of the deviations can be roughly classified into three categories, including the measurement error, the offset error, and the lateral error. Empirical correction strategies for the formal two errors have been promoted in previous study, but lack of theoretical support. In this paper, we will provide quantitative description of the three type of errors and discuss the related error compensation methods. Vehicle and shipborne experiments were carried out to verify the feasibility of the proposed correction methods. Keywords: Error compensation; Single-antenna; GNSS; Attitude determination; Low-dynamic

A preliminary 6 DOF attitude and translation control system design for Starprobe

NASA Technical Reports Server (NTRS)

Mak, P.; Mettler, E.; Vijayarahgavan, A.

1981-01-01

The extreme thermal environment near perihelion and the high-accuracy gravitational science experiments impose unique design requirements on various subsystems of Starprobe. This paper examines some of these requirements and their impact on the preliminary design of a six-degree-of-freedom attitude and translational control system. Attention is given to design considerations, the baseline attitude/translational control system, system modeling, and simulation studies.

Stabilization of a programmed rotation mode for a satellite with electrodynamic attitude control system

NASA Astrophysics Data System (ADS)

Aleksandrov, A. Yu.; Aleksandrova, E. B.; Tikhonov, A. A.

2018-07-01

The paper deals with a dynamically symmetric satellite in a circular near-Earth orbit. The satellite is equipped with an electrodynamic attitude control system based on Lorentz and magnetic torque properties. The programmed satellite attitude motion is such that the satellite slowly rotates around the axis of its dynamical symmetry. Unlike previous publications, we consider more complex and practically more important case where the axis is fixed in the orbital frame in an inclined position with respect to the local vertical axis. The satellite stabilization in the programmed attitude motion is studied. The gravitational disturbing torque acting on the satellite attitude dynamics is taken into account since it is the largest disturbing torque. The novelty of the proposed approach is based on the usage of electrodynamic attitude control system. With the aid of original construction of a Lyapunov function, new conditions under which electrodynamic control solves the problem are obtained. Sufficient conditions for asymptotic stability of the programmed motion are found in terms of inequalities for the values of control parameters. The results of a numerical simulation are presented to demonstrate the effectiveness of the proposed approach.

Hubble Space Telescope Magnetometer and Two-Gyro Control Law Design, Implementation, and On-Orbit Performance. Part 1

NASA Technical Reports Server (NTRS)

Wirzburger, John H.

2005-01-01

For f i h years, the science mission of the Hubble Space Telescope (HST) required using at least three of six rate gyros for attitude control. In the past, HST has mitigated gyro hardware failures by replacement of the failed units through Space Shuttle Servicing Missions. Following the tragic loss of Space Shuttle Columbia on STS-107, the desire to have a safe haven for astronauts during missions has resulted in the cancellation of all planned maxu14 missions to HST. While a robotic servicing mission is being currently being planned, controlling with alternate sensors to replace failed gyros can extend the HST Science mission until the robotic mission can be performed and extend science at HST s end of life. A two-gym control law has been designed and implemented using magnetometers (Magnetic Sensing System - MSS), fixed head star trackers (FHSTs), and Fine Guidance Sensors (FGSs) to control vehicle rate about the missing gyro axis. The three aforementioned sensors are used in succession to reduce HST boresight jitter to less than 7 milli-arcseconds rms and attitude error to less than 10 milli-arcseconds prior to science imaging. The MSS and 2-Gyro (M2G) control law is used for large angle maneuvers and attitude control during earth occultation of FHSTs and FGSs. The Tracker and 2-Gyro (T2G) control law dampens M2G rates and corrects the majority of attitude error in preparation for guide star acquisition with the FGSs. The Fine Guidance Sensor and 2-Gyro (F2G) control law d a m p T2G rates and controls HST attitude during science imaging. This paper describes the M2G control law. Details of M2G algorithms are presented, including computation of the HST 3-axis attitude error estimate, design of the M2G control law, SISO hear stability analyses, and restrictions on operations to maintain the h d t h and safety requirement of a 10degree maximum attitude error. Results of simulations performed in HSTSIM, a high-fidelity non-linear time domain simulation, are presented to predict HST on-orbit performance in attitude hold and maneuver modes. Simulation results are compared to on-orbit data from M2G flight tests performed in November and December 2004 and February 2005. Flight telemetry, using a currently available third gyro, shows that HST attitude error with the new M2G control law is maintained below the 10-degree requirement, and attitude errors are under 2 degrees for 95% of the time.

The role of tobacco-specific media exposure, knowledge, and smoking status on selected attitudes toward tobacco control.

PubMed

Blake, Kelly D; Viswanath, K; Blendon, Robert J; Vallone, Donna

2010-02-01

In August 2007, the President's Cancer Panel urged the leadership of the nation to "summon the political will to address the public health crisis caused by tobacco use" (President's Cancer Panel, N, 2007, Promoting healthy lifestyles: Policy, program, and personal recommendations for reducing cancer risk. http://deainfo.nci.nih.gov/advisory/pcp/pcp07rpt/pcp07rpt.pdf). While some research has examined predictors of public support for tobacco control measures, little research has examined modifiable factors that may influence public attitudes toward tobacco control. We used the American Legacy Foundation's 2003 American Smoking and Health Survey 2 to examine the contribution of smoking status, knowledge of the negative effects of tobacco, and tobacco-specific media exposure (antitobacco messages, news coverage of tobacco issues, and protobacco advertising) on U.S. adults' attitudes toward tobacco control. In addition, we assessed whether smoking status moderates the relationship between tobacco-specific media exposure and policy attitudes. Weighted multivariable logistic regression models were employed. Results suggest that knowledge of the negative effects of tobacco and smoking status are associated with attitudes toward tobacco control and that exposure to tobacco-specific information in the media plays a role only in some instances. We found no evidence of effect modification by smoking status on the impact of exposure to tobacco-specific media on attitudes toward tobacco control. Understanding the impact of readily modifiable factors that shape policy attitudes is essential if we are to target outreach and education in a way that is likely to sway public support for tobacco control.

Decentralized finite-time attitude synchronization for multiple rigid spacecraft via a novel disturbance observer.

PubMed

Zong, Qun; Shao, Shikai

2016-11-01

This paper investigates decentralized finite-time attitude synchronization for a group of rigid spacecraft by using quaternion with the consideration of environmental disturbances, inertia uncertainties and actuator saturation. Nonsingular terminal sliding mode (TSM) is used for controller design. Firstly, a theorem is proven that there always exists a kind of TSM that converges faster than fast terminal sliding mode (FTSM) for quaternion-descripted attitude control system. Controller with this kind of TSM has faster convergence and reduced computation than FTSM controller. Then, combining with an adaptive parameter estimation strategy, a novel terminal sliding mode disturbance observer is proposed. The proposed disturbance observer needs no upper bound information of the lumped uncertainties or their derivatives. On the basis of undirected topology and the disturbance observer, decentralized attitude synchronization control laws are designed and all attitude errors are ensured to converge to small regions in finite time. As for actuator saturation problem, an auxiliary variable is introduced and accommodated by the disturbance observer. Finally, simulation results are given and the effectiveness of the proposed control scheme is testified. Copyright © 2016. Published by Elsevier Ltd.

MEMS Reaction Control and Maneuvering for Picosat Beyond LEO

NASA Technical Reports Server (NTRS)

Alexeenko, Alina

2016-01-01

The MEMS Reaction Control and Maneuvering for Picosat Beyond LEO project will further develop a multi-functional small satellite technology for low-power attitude control, or orientation, of picosatellites beyond low Earth orbit (LEO). The Film-Evaporation MEMS Tunable Array (FEMTA) concept initially developed in 2013, is a thermal valving system which utilizes capillary forces in a microchannel to offset internal pressures in a bulk fluid. The local vapor pressure is increased by resistive film heating until it exceeds meniscus strength in a nozzle which induces vacuum boiling and provides a stagnation pressure equal to vapor pressure at that point which is used for propulsion. Interplanetary CubeSats can utilize FEMTA for high slew rate attitude corrections in addition to desaturating reaction wheels. The FEMTA in cooling mode can be used for thermal control during high-power communication events, which are likely to accompany the attitude correction. Current small satellite propulsion options are limited to orbit correction whereas picosatellites are lacking attitude control thrusters. The available attitude control systems are either quickly saturated reaction wheels or movable high drag surfaces with long response times.

Improving Primary Teachers' Attitudes toward Science by Attitude-Focused Professional Development

ERIC Educational Resources Information Center

van Aalderen-Smeets, Sandra I.; van der Molen, Juliette H. Walma

2015-01-01

This article provides a description of a novel, attitude-focused, professional development intervention, and presents the results of an experimental pretest-posttest control group study investigating the effects of this intervention on primary teachers' personal attitudes toward science, attitudes toward teaching science, and their science…

Two Axis Pointing System (TAPS) attitude acquisition, determination, and control

NASA Technical Reports Server (NTRS)

Azzolini, John D.; Mcglew, David E.

1990-01-01

The Two Axis Pointing System (TAPS) is a 2 axis gimbal system designed to provide fine pointing of Space Transportation System (STS) borne instruments. It features center-of-mass instrument mounting and will accommodate instruments of up to 1134 kg (2500 pounds) which fit within a 1.0 by 1.0 by 4.2 meter (40 by 40 by 166 inch) envelope. The TAPS system is controlled by a microcomputer based Control Electronics Assembly (CEA), a Power Distribution Unit (PDU), and a Servo Control Unit (SCU). A DRIRU-II inertial reference unit is used to provide incremental angles for attitude propagation. A Ball Brothers STRAP star tracker is used for attitude acquisition and update. The theory of the TAPS attitude determination and error computation for the Broad Band X-ray Telescope (BBXRT) are described. The attitude acquisition is based upon a 2 star geometric solution. The acquisition theory and quaternion algebra are presented. The attitude control combines classical position, integral and derivative (PID) control with techniques to compensate for coulomb friction (bias torque) and the cable harness crossing the gimbals (spring torque). Also presented is a technique for an adaptive bias torque compensation which adjusts to an ever changing frictional torque environment. The control stability margins are detailed, with the predicted pointing performance, based upon simulation studies. The TAPS user interface, which provides high level operations commands to facilitate science observations, is outlined.

Knowledge and attitude of key community members towards tuberculosis: mixed method study from BRAC TB control areas in Bangladesh.

PubMed

Paul, Sukanta; Akter, Rahima; Aftab, Afzal; Khan, Antora M; Barua, Mrittika; Islam, Shayla; Islam, Akramul; Husain, Ashaque; Sarker, Malabika

2015-01-31

Bangladesh National Tuberculosis (TB) Control Programme adopted a number of strategies to facilitate TB diagnosis and treatment. 'Advocacy, Communication and Social Mobilization' (ACSM) was one of the key strategies implemented by BRAC (Bangladesh Rural Advancement Committee, a non-governmental development organization) TB control program. The purpose of this study is to assess the knowledge and attitudes of the key community members (KCMs) participated in ACSM in BRAC TB control areas. This study combined quantitative and qualitative methods using a mixed method approach. KCMs in three districts with low TB case detection rates were targeted to assess the ACSM program. The quantitative survey using a multi-stage random-sampling strategy was conducted among 432 participants. The qualitative study included in-depth interviews (IDIs) of a sub sample of 48 respondents. For quantitative analysis, descriptive statistics were reported using frequencies, percentages, and Chi square tests, while thematic analysis was used for qualitative part. Most (99%) of the participants had heard about TB, and almost all knew that TB is a contagious yet curable disease. More than half (53%) of the KCMs had good knowledge regarding TB, but BRAC workers were found to be more knowledgeable compared to other KCMs. However, considerable knowledge gaps were observed among BRAC community health workers. Qualitative results revealed that the majority of the KCMs were aware about the signs, symptoms and transmission pathways of TB and believed that smoking and addiction were the prime causes of transmission of TB. The knowledge about child TB was poor even among BRAC health workers. Stigma associated with TB was not uncommon. Almost all respondents expressed that young girls diagnosed with TB. This study finding has revealed varying levels of knowledge and mixed attitudes about TB among the KCMs. It also provides insight on the poor knowledge regarding child TB and indicate that despite the significant success of the TB program stigma is yet prevalent in the community. Future ACSM activities should engage community members against stigma and promote child TB related information for further improvement of BRAC TB Control Programme.

A cross-sectional assessment of knowledge, attitude and practice among Hepatitis-B patients in Quetta, Pakistan

PubMed Central

2013-01-01

Background Hepatitis-B is a life threatening infection resulting in 0.6 million deaths annually. The prevalence of Hepatitis-B is rising in Pakistan and furthermore, there is paucity of information about Knowledge, Attitude and Practice among Hepatitis-B patients. Better disease related knowledge is important to have positive attitude and that will bring the good practices which will prevent the further spread of infection. This study aimed to evaluate knowledge, attitude and practice of Hepatitis-B Patients in Quetta city, Pakistan. Methods A cross-sectional, descriptive study was undertaken with 390 Hepatitis-B patients attending two public hospitals in Quetta city, Pakistan. Knowledge, attitude and practice regarding Hepatitis-B were assessed using a pre-validated questionnaire containing 20, 7 and 8 questions for knowledge, attitude and practice, respectively. Descriptive statistics were used for elaborating patients’ demographic characteristics and mean scores for knowledge, attitude and practice of Hepatitis-B patients. Inferential statistics (Mann–Whitney U test and Kruskal Wallis tests, p < 0.05) were used to establish association between study variables. Spearman’s rho correlation was used to identify the association between the knowledge, attitude and practice scores. Results Out of 390 patients, 223 (57.2%) were males, with the majority (136, 34.9%) in the age group of 38–47 years. Mean age of the study cohort was 32.6 ± 9.5 years. One hundred and four (26.7%) had primary level education, with 110 (28.2%) working in the private sector. The mean scores for knowledge, attitude and practice were 8.48 ± 2.7, 3.87 ± 1.2 and 2.37 ± 1.0, respectively. Education, locality and occupation were significantly associated with knowledge, attitude and practice scores. Significant positive linear correlations between knowledge-attitude (r = 0.466, p < 0.01) knowledge-practice (r = 0.221, p < 0.01) and attitude-practice (r = 0.224, p < 0.01) were also observed from the study results. Conclusion The findings of this study indicate that Hepatitis-B patients lack a basic understanding of infection control and management. This can result in the further spread of Hepatitis-B infection. Extensive health education campaigns should be provided to the patients in the hospital as well as in community settings for rational control and management of the disease. PMID:23641704

Nurses' attitudes to terminally ill patients.

PubMed

Román, E M; Sorribes, E; Ezquerro, O

2001-05-01

The care of terminally ill patients is a challenge for nurses that has raised special interest in recent years. Several studies have shown a stereotyped negative attitude in nurses towards terminally ill patients. However, all have used methods with several limitations. The aim of the study presented in this paper was to identify the nurses' attitude to the terminally ill patient in Catalonia, Spain, and the relationship of this attitude to different socio-demographic data (type of centre, shift, years of experience, age and sex) by means of a new quantitative method based on the free word-association test. One hundred and seventy-five nurses working in 18 hospitals and hospices in Catalonia, Spain were included in the study. Data were analysed by the Associative Semantic Field Differential method by means of the computer programme CONTEXT and a quantitative evaluation of the degree of attitudes positivity was obtained. The study revealed a general slight negative trend in attitudes towards the terminally ill patient. A more positive attitude was observed in older caregivers and in women. The positivity in attitude decreased from morning to night shift. No differences were observed between nurses working in hospitals and those working in hospices. We conclude that nursing attitudes can be analysed by methods such as that used in this study. Attempts can be made to modify this attitude in caregivers by means of training programmes and stimulating awareness of an adequate professional approach.

Fault tolerant attitude control for small unmanned aircraft systems equipped with an airflow sensor array.

PubMed

Shen, H; Xu, Y; Dickinson, B T

2014-11-18

Inspired by sensing strategies observed in birds and bats, a new attitude control concept of directly using real-time pressure and shear stresses has recently been studied. It was shown that with an array of onboard airflow sensors, small unmanned aircraft systems can promptly respond to airflow changes and improve flight performances. In this paper, a mapping function is proposed to compute aerodynamic moments from the real-time pressure and shear data in a practical and computationally tractable formulation. Since many microscale airflow sensors are embedded on the small unmanned aircraft system surface, it is highly possible that certain sensors may fail. Here, an adaptive control system is developed that is robust to sensor failure as well as other numerical mismatches in calculating real-time aerodynamic moments. The advantages of the proposed method are shown in the following simulation cases: (i) feedback pressure and wall shear data from a distributed array of 45 airflow sensors; (ii) 50% failure of the symmetrically distributed airflow sensor array; and (iii) failure of all the airflow sensors on one wing. It is shown that even if 50% of the airflow sensors have failures, the aircraft is still stable and able to track the attitude commands.

University and student segmentation: multilevel latent-class analysis of students' attitudes towards research methods and statistics.

PubMed

Mutz, Rüdiger; Daniel, Hans-Dieter

2013-06-01

It is often claimed that psychology students' attitudes towards research methods and statistics affect course enrollment, persistence, achievement, and course climate. However, the inter-institutional variability has been widely neglected in the research on students' attitudes towards research methods and statistics, but it is important for didactic purposes (heterogeneity of the student population). The paper presents a scale based on findings of the social psychology of attitudes (polar and emotion-based concept) in conjunction with a method for capturing beginning university students' attitudes towards research methods and statistics and identifying the proportion of students having positive attitudes at the institutional level. The study based on a re-analysis of a nationwide survey in Germany in August 2000 of all psychology students that enrolled in fall 1999/2000 (N= 1,490) and N= 44 universities. Using multilevel latent-class analysis (MLLCA), the aim was to group students in different student attitude types and at the same time to obtain university segments based on the incidences of the different student attitude types. Four student latent clusters were found that can be ranked on a bipolar attitude dimension. Membership in a cluster was predicted by age, grade point average (GPA) on school-leaving exam, and personality traits. In addition, two university segments were found: universities with an average proportion of students with positive attitudes and universities with a high proportion of students with positive attitudes (excellent segment). As psychology students make up a very heterogeneous group, the use of multiple learning activities as opposed to the classical lecture course is required. © 2011 The British Psychological Society.

1999 Flight Mechanics Symposium

NASA Technical Reports Server (NTRS)

Lynch, John P. (Editor)

1999-01-01

This conference publication includes papers and abstracts presented at the Flight Mechanics Symposium held on May 18-20, 1999. Sponsored by the Guidance, Navigation and Control Center of Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to orbit-attitude prediction, determination, and control; attitude sensor calibration; attitude determination error analysis; attitude dynamics; and orbit decay and maneuver strategy. Government, industry, and the academic community participated in the preparation and presentation of these papers.

Does Exonerating an Accused Researcher Restore the Researcher's Credibility?

PubMed

Greitemeyer, Tobias; Sagioglou, Christina

2015-01-01

Scientific misconduct appears to be on the rise. However, an accused researcher may later be exonerated. The present research examines to what extent participants adhere to their attitude toward a researcher who allegedly committed academic misconduct after learning that the researcher is innocent. In two studies, participants in an exoneration and an uncorrected accusation condition learned that the ethics committee of a researcher's university demanded the retraction of one of the researcher's articles, whereas participants in a control condition did not receive this information. As intended, this manipulation led to a more favorable attitude toward the researcher in the control compared to the exoneration and the uncorrected accusation conditions (pre-exoneration attitude). Then, participants in the exoneration condition learned that the researcher was exonerated and that the article was not retracted. Participants in the uncorrected accusation and the control condition were not informed about the exoneration. Results revealed that the exoneration effectively worked, in that participants in the exoneration condition had a more favorable attitude (post-exoneration attitude) toward the researcher than did participants in the uncorrected accusation condition. Moreover, the post-exoneration attitude toward the researcher was similar in the exoneration and the control conditions. Finally, in the exoneration condition only, participants' post-exoneration attitude was more favorable than their pre-exoneration attitude. These findings suggest that an exoneration of an accused researcher restores the researcher's credibility.

Modeling and Control of a Tailsitter with a Ducted Fan

NASA Astrophysics Data System (ADS)

Argyle, Matthew Elliott

There are two traditional aircraft categories: fixed-wing which have a long endurance and a high cruise airspeed and rotorcraft which can take-off and land vertically. The tailsitter is a type of aircraft that has the strengths of both platforms, with no additional mechanical complexity, because it takes off and lands vertically on its tail and can transition the entire aircraft horizontally into high-speed flight. In this dissertation, we develop the entire control system for a tailsitter with a ducted fan. The standard method to compute the quaternion-based attitude error does not generate ideal trajectories for a hovering tailsitter for some situations. In addition, the only approach in the literature to mitigate this breaks down for large attitude errors. We develop an alternative quaternion-based error method which generates better trajectories than the standard approach and can handle large errors. We also derive a hybrid backstepping controller with almost global asymptotic stability based on this error method. Many common altitude and airspeed control schemes for a fixed-wing airplane assume that the altitude and airspeed dynamics are decoupled which leads to errors. The Total Energy Control System (TECS) is an approach that controls the altitude and airspeed by manipulating the total energy rate and energy distribution rate, of the aircraft, in a manner which accounts for the dynamic coupling. In this dissertation, a nonlinear controller, which can handle inaccurate thrust and drag models, based on the TECS principles is derived. Simulation results show that the nonlinear controller has better performance than the standard PI TECS control schemes. Most constant altitude transitions are accomplished by generating an optimal trajectory, and potentially actuator inputs, based on a high fidelity model of the aircraft. While there are several approaches to mitigate the effects of modeling errors, these do not fully remove the accurate model requirement. In this dissertation, we develop two different approaches that can achieve near constant altitude transitions for some types of aircraft. The first method, based on multiple LQR controllers, requires a high fidelity model of the aircraft. However, the second method, based on the energy along the body axes, requires almost no aerodynamic information.

Registration of Panoramic/Fish-Eye Image Sequence and LiDAR Points Using Skyline Features

PubMed Central

Zhu, Ningning; Jia, Yonghong; Ji, Shunping

2018-01-01

We propose utilizing a rigorous registration model and a skyline-based method for automatic registration of LiDAR points and a sequence of panoramic/fish-eye images in a mobile mapping system (MMS). This method can automatically optimize original registration parameters and avoid the use of manual interventions in control point-based registration methods. First, the rigorous registration model between the LiDAR points and the panoramic/fish-eye image was built. Second, skyline pixels from panoramic/fish-eye images and skyline points from the MMS’s LiDAR points were extracted, relying on the difference in the pixel values and the registration model, respectively. Third, a brute force optimization method was used to search for optimal matching parameters between skyline pixels and skyline points. In the experiments, the original registration method and the control point registration method were used to compare the accuracy of our method with a sequence of panoramic/fish-eye images. The result showed: (1) the panoramic/fish-eye image registration model is effective and can achieve high-precision registration of the image and the MMS’s LiDAR points; (2) the skyline-based registration method can automatically optimize the initial attitude parameters, realizing a high-precision registration of a panoramic/fish-eye image and the MMS’s LiDAR points; and (3) the attitude correction values of the sequences of panoramic/fish-eye images are different, and the values must be solved one by one. PMID:29883431

Take It or Leave It: Students' Attitudes about Research Methods

ERIC Educational Resources Information Center

Wisecup, Allison K.

2017-01-01

This study employs a cross-sectional design to explore sociology majors' attitudes toward research methods. Survey data from a convenience sample of students enrolled in 16 departments are used to compare the attitudes of students who have and have not completed a research methods course. Despite consistent anecdotal claims that students harbor…

University and Student Segmentation: Multilevel Latent-Class Analysis of Students' Attitudes towards Research Methods and Statistics

ERIC Educational Resources Information Center

Mutz, Rudiger; Daniel, Hans-Dieter

2013-01-01

Background: It is often claimed that psychology students' attitudes towards research methods and statistics affect course enrolment, persistence, achievement, and course climate. However, the inter-institutional variability has been widely neglected in the research on students' attitudes towards research methods and statistics, but it is important…

Parental attitudes and aggression in the Emo subculture.

PubMed

Chęć, Magdalena; Potemkowski, Andrzej; Wąsik, Marta; Samochowiec, Agnieszka

2016-01-01

A better functioning of adolescents involves proper relationships with parents, whereas negative relationships lead to aggressive behaviour. Young members of Emo subculture, characterised by deep emotional sensitivity, are particularly vulnerable to parental influence. The aim was to specify a relationship between parental attitudes and aggression among adolescents from the Emo subculture in comparison with a control group. 3,800 lower secondary school students took part in the introductory research. A target group constituted 41 people from the Emo subculture as well as a control group involving 48 people. A screening survey, the Parental Attitudes Scale, the Aggression Questionnaire and the author's questionnaire including questions concerning the functioning in the Emo subculture were used in the study. The results obtained in the research study suggest that there is a relationship between the indicated improper parental attitudes and aggressive behaviour among adolescents from the Emo subculture in comparison with the control group. In the Emo subculture, teenagers'aggressive behaviour is related to improper parental attitudes. It has been stated that mother's attitudes, irrespective of subculture, are much more strongly associated with the aggression among adolescents than father's attitudes. Moreover, aggressive behaviour in the Emo subculture occurs when father displays an excessively demanding attitude. A reduction of the level of almost all kinds of aggression manifested among teenagers from the Emo subculture is associated with mothers' attitude of acceptance. Mothers' autonomous attitude leads to an increase in the aggression in this group, whereas an inconsistent attitude of mothers fosters an increase in aggression among all teenagers.

Effect of e-cigarette advertisements and antismoking messages on explicit and implicit attitudes towards tobacco and e-cigarette smoking in 18–65-year-olds: a randomised controlled study protocol

PubMed Central

Albery, Ian P; Frings, Daniel

2017-01-01

Introduction Since the advent of e-cigarettes, e-cigarette advertising has escalated and companies are able to use marketing strategies that are not permissible for tobacco products. Research into the effect of e-cigarette advertising on attitudes towards tobacco and e-cigarettes is in its infancy. To date, no research has compared indirect (implicit) measures of attitude towards e-cigarettes with direct (explicit) measures. Furthermore, little consideration has been given to how viewing online advertisements may have an effect on attitudes towards e-cigarettes or how positive attitudes to e-cigarettes may undermine antismoking public health messages. The objectives of this study are to investigate (1) the relationship between explicit and implicit attitudes towards tobacco and e-cigarettes, (2) the effect of e-cigarette advertising on these attitudes and (3) the effect of these attitudes on the efficacy of antismoking health messages. Methods and analysis In experiment 1 an analysis of covariance will be conducted to determine whether viewing an e-cigarette advertisement, compared with a neutral image, has an effect on implicit or explicit attitudes towards tobacco and e-cigarettes, and if these attitudes differ between smokers, vapers and non-smokers aged 18 - 25 years. In experiment 2, moderation analysis will be conducted to assess whether attitudes towards e-cigarettes moderate the psychological efficacy of antismoking health messages in participants aged 18–65 years. In each experiment, attitudes will be measured preintervention and postintervention and 1 week later (n=150) in participants who are smokers (n=50), vapers (n=50) or non-smokers (n=50). Ethics and dissemination Approval for this study has been given by the London South Bank University’s (LSBU) Research Ethics Committee. The findings of these studies will be submitted for publication and disseminated via conferences. The results will be integrated into course provision for practitioners training at LSBU. PMID:28645957

X-33 Attitude Control Using the XRS-2200 Linear Aerospike Engine

NASA Technical Reports Server (NTRS)

Hall, Charles E.; Panossian, Hagop V.

1999-01-01

The Vehicle Control Systems Team at Marshall Space Flight Center, Structures and Dynamics Laboratory, Guidance and Control Systems Division is designing, under a cooperative agreement with Lockheed Martin Skunkworks, the Ascent, Transition, and Entry flight attitude control systems for the X-33 experimental vehicle. Test flights, while suborbital, will achieve sufficient altitudes and Mach numbers to test Single Stage To Orbit, Reusable Launch Vehicle technologies. Ascent flight control phase, the focus of this paper, begins at liftoff and ends at linear aerospike main engine cutoff (MECO). The X-33 attitude control system design is confronted by a myriad of design challenges: a short design cycle, the X-33 incremental test philosophy, the concurrent design philosophy chosen for the X-33 program, and the fact that the attitude control system design is, as usual, closely linked to many other subsystems and must deal with constraints and requirements from these subsystems. Additionally, however, and of special interest, the use of the linear aerospike engine is a departure from the gimbaled engines traditionally used for thrust vector control (TVC) in launch vehicles and poses certain design challenges. This paper discusses the unique problem of designing the X-33 attitude control system with the linear aerospike engine, requirements development, modeling and analyses that verify the design.

Application of GPS attitude determination to gravity gradient stabilized spacecraft

NASA Technical Reports Server (NTRS)

Lightsey, E. G.; Cohen, Clark E.; Parkinson, Bradford W.

1993-01-01

Recent advances in the Global Positioning System (GPS) technology have initiated a new era in aerospace navigation and control. GPS receivers have become increasingly compact and affordable, and new developments have made attitude determination using subcentimeter positioning among two or more antennas feasible for real-time applications. GPS-based attitude control systems will become highly portable packages which provide time, navigation, and attitude information of sufficient accuracy for many aerospace needs. A typical spacecraft application of GPS attitude determination is a gravity gradient stabilized satellite in low Earth orbit that employs a GPS receiver and four body mounted patch antennas. The coupled, linearized equations of motion enable complete position and attitude information to be extracted from only two antennas. A discussion of the various error sources for spaceborne GPS attitude measurement systems is included. Attitude determination of better than 0.3 degrees is possible for 1 meter antenna separation. Suggestions are provided to improve the accuracy of the attitude solution.

[Knowledge, attitude and practice related to schistosomiasis control among rural residents in Wanjiang River region after a flood].

PubMed

Huan, Liu; Ai-Xia, Wang; Yuan-Zhen, Li; Ming-Ming, Zhou

2017-02-22

To investigate the status of knowledge, attitude and behavior of schistosomiasis control of rural residents in Wanjiang River region after a flood, so as to provide the reference for targeted health education. The multistage sampling was applied to select the respondents in rural residents in Wanjiang River region, and the self-designed questionnaire was used to investigate the current situation of knowledge, attitude and behavior of schistosomiasis prevention and control of the rural residents. The total awareness rate of knowledge about the prevention and control of schistosomiasis was 47.92%. The age, education, family income, relatives and friends with medical background, and health education significantly influenced the awareness rate ( χ 2 = 12.76, 89.19, 18.19, 50.83 and 92.60 respectively, all P < 0.05). The accuracy rates of attitude and behavior in schistosomiasis control were 62.89% and 52.37% respectively. The awareness rate of knowledge about the prevention and control of schistosomiasis, and the accuracy rates of attitude and behavior in schistosomiasis control of the rural residents in Wanjiang River region are all inefficient, and therefore, the targeted health education should be strengthened to decrease the risk of schistosomiasis transmission.

Large scale static tests of a tilt-nacelle V/STOL propulsion/attitude control system

NASA Technical Reports Server (NTRS)

1978-01-01

The concept of a combined V/STOL propulsion and aircraft attitude control system was subjected to large scale engine tests. The tilt nacelle/attitude control vane package consisted of the T55 powered Hamilton Standard Q-Fan demonstrator. Vane forces, moments, thermal and acoustic characteristics as well as the effects on propulsion system performance were measured under conditions simulating hover in and out of ground effect.

Neural network disturbance observer-based distributed finite-time formation tracking control for multiple unmanned helicopters.

PubMed

Wang, Dandan; Zong, Qun; Tian, Bailing; Shao, Shikai; Zhang, Xiuyun; Zhao, Xinyi

2018-02-01

The distributed finite-time formation tracking control problem for multiple unmanned helicopters is investigated in this paper. The control object is to maintain the positions of follower helicopters in formation with external interferences. The helicopter model is divided into a second order outer-loop subsystem and a second order inner-loop subsystem based on multiple-time scale features. Using radial basis function neural network (RBFNN) technique, we first propose a novel finite-time multivariable neural network disturbance observer (FMNNDO) to estimate the external disturbance and model uncertainty, where the neural network (NN) approximation errors can be dynamically compensated by adaptive law. Next, based on FMNNDO, a distributed finite-time formation tracking controller and a finite-time attitude tracking controller are designed using the nonsingular fast terminal sliding mode (NFTSM) method. In order to estimate the second derivative of the virtual desired attitude signal, a novel finite-time sliding mode integral filter is designed. Finally, Lyapunov analysis and multiple-time scale principle ensure the realization of control goal in finite-time. The effectiveness of the proposed FMNNDO and controllers are then verified by numerical simulations. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Evaluation of life and death studies course on attitudes toward life and death among nursing students.

PubMed

Hwang, Huei-Lih; Lin, Huey-Shyan; Chen, Wen-Tin

2005-12-01

The aim of this study was to evaluate attitudes toward life and death among nursing students after attending the life and death studies (LDS) program. Both qualitative and quantitative methods were used to collect data. The pretest-posttest control group design randomly assigned students to an experimental (n = 47) or control group (n = 49). The 13-week course included lectures, video appraisal, games, simulations, films, books, assignments and group sharing. Statistical and content analysis were used to analyze qualitative and quantitative data. The findings showed a significant improvement in perception of the meaningfulness of life in four categories of improvement: expanded viewpoint, sadness about death, treating life sincerely, and instilling hope in life. The qualitative data indicated that a positive change in meaning of life was associated with interaction with others and self-reflection.

Optimal Control Method of Robot End Position and Orientation Based on Dynamic Tracking Measurement

NASA Astrophysics Data System (ADS)

Liu, Dalong; Xu, Lijuan

2018-01-01

In order to improve the accuracy of robot pose positioning and control, this paper proposed a dynamic tracking measurement robot pose optimization control method based on the actual measurement of D-H parameters of the robot, the parameters is taken with feedback compensation of the robot, according to the geometrical parameters obtained by robot pose tracking measurement, improved multi sensor information fusion the extended Kalan filter method, with continuous self-optimal regression, using the geometric relationship between joint axes for kinematic parameters in the model, link model parameters obtained can timely feedback to the robot, the implementation of parameter correction and compensation, finally we can get the optimal attitude angle, realize the robot pose optimization control experiments were performed. 6R dynamic tracking control of robot joint robot with independent research and development is taken as experimental subject, the simulation results show that the control method improves robot positioning accuracy, and it has the advantages of versatility, simplicity, ease of operation and so on.

Impact and change of attitudes toward Internet interventions within a randomized controlled trial on individuals with depression symptoms.

PubMed

Schröder, Johanna; Berger, Thomas; Meyer, Björn; Lutz, Wolfgang; Späth, Christina; Michel, Pia; Rose, Matthias; Hautzinger, Martin; Hohagen, Fritz; Klein, Jan Philipp; Moritz, Steffen

2018-05-01

Most individuals with depression do not receive adequate treatment. Internet interventions may help to bridge this gap. Research on attitudes toward Internet interventions might facilitate the dissemination of such interventions by identifying factors that help or hinder uptake and implementation, and by clarifying who is likely to benefit. This study examined whether attitudes toward Internet interventions moderate the effects of a depression-focused Internet intervention, and how attitudes change over the course of treatment among those who do or do not benefit. We recruited 1,004 adults with mild-to-moderate depression symptoms and investigated how attitudes toward Internet interventions are associated with the efficacy of the program deprexis, and how attitudes in the intervention group change from pre to post over a 3 months intervention period, compared to a control group (care as usual). This study consists of a subgroup analysis of the randomized controlled EVIDENT trial. Positive initial attitudes toward Internet interventions were associated with greater efficacy (η 2 p  = .014) independent of usage time, whereas a negative attitude (perceived lack of personal contact) was associated with reduced efficacy (η 2 p  = .012). Users' attitudes changed during the trial, and both the magnitude and direction of attitude change were associated with the efficacy of the program over time (η 2 p  = .030). Internet interventions may be the most beneficial for individuals with positive attitudes toward them. Informing potential users about evidence-based Internet interventions might instill positive attitudes and thereby optimize the benefits such interventions can provide. Assessing attitudes prior to treatment might help identify suitable users. © 2018 Wiley Periodicals, Inc.

Testing messages to reduce smokers’ openness to using novel smokeless tobacco products

PubMed Central

Popova, Lucy; Neilands, Torsten B.; Ling, Pamela M.

2013-01-01

Introduction Tobacco manufacturers’ aggressive promotion of new smokeless tobacco products such as snus warrants a timely and effective public health response. This study tested potential counter-marketing messages to discourage current and former smokers from becoming dual users of smokeless tobacco and cigarettes. Methods In a pretest – post-test experiment, 1,836 adult current and recently former smokers from a national sample were randomized to view one of six anti-smokeless tobacco ads followed by a snus ad, to view a control ad followed by a snus ad; or to view two control ads. Perceived effectiveness of ads and actual changes in attitudes and openness to snus were compared across groups using analyses of variance. Results Some ads that were perceived as most effective did not change attitudes or openness to trying snus, and conversely, some ads not perceived as effective changed attitudes and openness to snus. Ads portraying the negative health effects of smokeless tobacco were perceived as most effective, but ads with anti-tobacco industry themes significantly decreased favorable attitudes toward snus. Responses to ads were different for smokers who had ever used smokeless tobacco: for this group health effects and humorous/testimonial ads were effective. Conclusions Measures of perceived effectiveness of anti-tobacco ads need to be augmented with measures of actual effectiveness to assess counter-marketing messages. Some of the developed ads, such as ads with anti-industry themes, were effective for the overall population of smokers whereas humorous/testimonial and health effects ads were particularly effective in changing attitudes of past users of smokeless tobacco. PMID:23467655

Opportunities for Improved Chagas Disease Vector Control Based on Knowledge, Attitudes and Practices of Communities in the Yucatan Peninsula, Mexico

PubMed Central

Rosecrans, Kathryn; Cruz-Martin, Gabriela; King, Ashley; Dumonteil, Eric

2014-01-01

Background Chagas disease is a vector-borne parasitic disease of major public health importance. Current prevention efforts are based on triatomine vector control to reduce transmission to humans. Success of vector control interventions depends on their acceptability and value to affected communities. We aimed to identify opportunities for and barriers to improved vector control strategies in the Yucatan peninsula, Mexico. Methodology/principal findings We employed a sequence of qualitative and quantitative research methods to investigate knowledge, attitudes and practices surrounding Chagas disease, triatomines and vector control in three rural communities. Our combined data show that community members are well aware of triatomines and are knowledgeable about their habits. However, most have a limited understanding of the transmission dynamics and clinical manifestations of Chagas disease. While triatomine control is not a priority for community members, they frequently use domestic insecticide products including insecticide spray, mosquito coils and plug-in repellents. Families spend about $32 US per year on these products. Alternative methods such as yard cleaning and window screens are perceived as desirable and potentially more effective. Screens are nonetheless described as unaffordable, in spite of a cost comparable to the average annual spending on insecticide products. Conclusion/Significance Further education campaigns and possibly financing schemes may lead families to redirect their current vector control spending from insecticide products to window screens. Also, synergism with mosquito control efforts should be further explored to motivate community involvement and ensure sustainability of Chagas disease vector control. PMID:24676038