Temperature Effects and Compensation-Control Methods

PubMed Central

Xia, Dunzhu; Chen, Shuling; Wang, Shourong; Li, Hongsheng

2009-01-01

In the analysis of the effects of temperature on the performance of microgyroscopes, it is found that the resonant frequency of the microgyroscope decreases linearly as the temperature increases, and the quality factor changes drastically at low temperatures. Moreover, the zero bias changes greatly with temperature variations. To reduce the temperature effects on the microgyroscope, temperature compensation-control methods are proposed. In the first place, a BP (Back Propagation) neural network and polynomial fitting are utilized for building the temperature model of the microgyroscope. Considering the simplicity and real-time requirements, piecewise polynomial fitting is applied in the temperature compensation system. Then, an integral-separated PID (Proportion Integration Differentiation) control algorithm is adopted in the temperature control system, which can stabilize the temperature inside the microgyrocope in pursuing its optimal performance. Experimental results reveal that the combination of microgyroscope temperature compensation and control methods is both realizable and effective in a miniaturized microgyroscope prototype. PMID:22408509

Increasing Medicaid child health screenings: the effectiveness of mailed pamphlets, phone calls, and home visits.

PubMed Central

Selby-Harrington, M; Sorenson, J R; Quade, D; Stearns, S C; Tesh, A S; Donat, P L

1995-01-01

OBJECTIVES. A randomized controlled trial was conducted to test the effectiveness and cost effectiveness of three outreach interventions to promote well-child screening for children on Medicaid. METHODS. In rural North Carolina, a random sample of 2053 families with children due or overdue for screening was stratified according to the presence of a home phone. Families were randomly assigned to receive a mailed pamphlet and letter, a phone call, or a home visit outreach intervention, or the usual (control) method of informing at Medicaid intake. RESULTS. All interventions produced more screenings than the control method, but increases were significant only for families with phones. Among families with phones, a home visit was the most effective intervention but a phone call was the most cost-effective. However, absolute rates of effectiveness were low, and incremental costs per effect were high. CONCLUSIONS. Pamphlets, phone calls, and home visits by nurses were minimally effective for increasing well-child screenings. Alternate outreach methods are needed, especially for families without phones. PMID:7573627

Effect of chemical and mechanical weed control on cassava yield, soil quality and erosion under cassava cropping system

NASA Astrophysics Data System (ADS)

Islami, Titiek; Wisnubroto, Erwin; Utomo, Wani

2016-04-01

Three years field experiments were conducted to study the effect of chemical and mechanical weed control on soil quality and erosion under cassava cropping system. The experiment were conducted at University Brawijaya field experimental station, Jatikerto, Malang, Indonesia. The experiments were carried out from 2011 - 2014. The treatments consist of three cropping system (cassava mono culture; cassava + maize intercropping and cassava + peanut intercropping), and two weed control method (chemical and mechanical methods). The experimental result showed that the yield of cassava first year and second year did not influenced by weed control method and cropping system. However, the third year yield of cassava was influence by weed control method and cropping system. The cassava yield planted in cassava + maize intercropping system with chemical weed control methods was only 24 t/ha, which lower compared to other treatments, even with that of the same cropping system used mechanical weed control. The highest cassava yield in third year was obtained by cassava + peanuts cropping system with mechanical weed control method. After three years experiment, the soil of cassava monoculture system with chemical weed control method possessed the lowest soil organic matter, and soil aggregate stability. During three years of cropping soil erosion in chemical weed control method, especially on cassava monoculture, was higher compared to mechanical weed control method. The soil loss from chemical control method were 40 t/ha, 44 t/ha and 54 t/ha for the first, second and third year crop. The soil loss from mechanical weed control method for the same years was: 36 t/ha, 36 t/ha and 38 t/ha. Key words: herbicide, intercropping, soil organic matter, aggregate stability.

Electrostatic discharge control for STDN stations

NASA Technical Reports Server (NTRS)

Mckiernan, J.

1983-01-01

This manual defines the requirements and control methods necessary to control the effect of electrostatic discharges that damage or destroy electronic equipment components. Test procedures for measuring the effectiveness of the control are included.

Effectiveness Comparison of TxDOT Quality Control/Quality Assurance and Method Specifications

DOT National Transportation Integrated Search

1998-12-01

Original Report date: October 1997. This is the first and final report for research project 0-1721, "Effectiveness Comparison of TxDOT Quality Control/Quality Assurance and Method Specifications." This study was established and sponsored by TxDOT to ...

A randomised controlled comparison of injection, thermal, and mechanical endoscopic methods of haemostasis on mesenteric vessels.

PubMed

Hepworth, C C; Kadirkamanathan, S S; Gong, F; Swain, C P

1998-04-01

A randomised controlled comparison of haemostatic efficacy of mechanical, injection, and thermal methods of haemostasis was undertaken using canine mesenteric vessels to test the hypothesis that mechanical methods of haemostasis are more effective in controlling haemorrhage than injection or thermal methods. The diameter of arteries in human bleeding ulcers measures up to 3.45 mm; mesenteric vessels up to 5 mm were therefore studied. Mesenteric vessels were randomised to treatment with injection sclerotherapy (adrenaline and ethanolamine), bipolar diathermy, or mechanical methods (band, clips, sewing machine, endoloops). The vessels were severed and haemostasis recorded. Injection sclerotherapy and clips failed to stop bleeding from vessels of 1 mm (n = 20) and 2 mm (n = 20). Bipolar diathermy was effective on 8/10 vessels of 2 mm but failed on 3 mm vessels (n = 5). Unstretched elastic bands succeeded on 13/15 vessels of 2 mm but on only 3/10 vessels of 3 mm. The sewing machine achieved haemostasis on 8/10 vessels of 4 mm but failed on 5 mm vessels (n = 5); endoloops were effective on all 5 mm vessels (n = 5). Only mechanical methods were effective on vessels greater than 2 mm in diameter. Some mechanical methods (banding and clips) were less effective than expected and need modification. Thermal and (effective) mechanical methods were significantly (p < 0.01) more effective than injection sclerotherapy. The most effective mechanical methods were significantly more effective (p < 0.01) than thermal or injection on vessels greater than 2 mm.

Virtual Passive Controller for Robot Systems Using Joint Torque Sensors

NASA Technical Reports Server (NTRS)

Aldridge, Hal A.; Juang, Jer-Nan

1997-01-01

This paper presents a control method based on virtual passive dynamic control that will stabilize a robot manipulator using joint torque sensors and a simple joint model. The method does not require joint position or velocity feedback for stabilization. The proposed control method is stable in the sense of Lyaponov. The control method was implemented on several joints of a laboratory robot. The controller showed good stability robustness to system parameter error and to the exclusion of nonlinear dynamic effects on the joints. The controller enhanced position tracking performance and, in the absence of position control, dissipated joint energy.

Optimal reorientation of asymmetric underactuated spacecraft using differential flatness and receding horizon control

NASA Astrophysics Data System (ADS)

Cai, Wei-wei; Yang, Le-ping; Zhu, Yan-wei

2015-01-01

This paper presents a novel method integrating nominal trajectory optimization and tracking for the reorientation control of an underactuated spacecraft with only two available control torque inputs. By employing a pseudo input along the uncontrolled axis, the flatness property of a general underactuated spacecraft is extended explicitly, by which the reorientation trajectory optimization problem is formulated into the flat output space with all the differential constraints eliminated. Ultimately, the flat output optimization problem is transformed into a nonlinear programming problem via the Chebyshev pseudospectral method, which is improved by the conformal map and barycentric rational interpolation techniques to overcome the side effects of the differential matrix's ill-conditions on numerical accuracy. Treating the trajectory tracking control as a state regulation problem, we develop a robust closed-loop tracking control law using the receding-horizon control method, and compute the feedback control at each control cycle rapidly via the differential transformation method. Numerical simulation results show that the proposed control scheme is feasible and effective for the reorientation maneuver.

Comparison of Control Group Generating Methods.

PubMed

Szekér, Szabolcs; Fogarassy, György; Vathy-Fogarassy, Ágnes

2017-01-01

Retrospective studies suffer from drawbacks such as selection bias. As the selection of the control group has a significant impact on the evaluation of the results, it is very important to find the proper method to generate the most appropriate control group. In this paper we suggest two nearest neighbors based control group selection methods that aim to achieve good matching between the individuals of case and control groups. The effectiveness of the proposed methods is evaluated by runtime and accuracy tests and the results are compared to the classical stratified sampling method.

Reverse matrix converter control method for PMSM drives using DPC

NASA Astrophysics Data System (ADS)

Bak, Yeongsu; Lee, Kyo-Beum

2018-05-01

This paper proposes a control method for a reverse matrix converter (RMC) that drives a three-phase permanent magnet synchronous motor (PMSM). In this proposed method, direct power control (DPC) is used to control the voltage source rectifier of the RMC. The RMC is an indirect matrix converter operating in the boost mode, in which the power-flow directions of the input and output are switched. It has a minimum voltage transfer ratio of 1/0.866 in a linear-modulation region. In this paper, a control method that uses DPC as an additional control method is proposed in order to control the RMC driving a PMSM in the output stage. Simulations and experimental results verify the effectiveness of the proposed control method.

Women and postfertilization effects of birth control: consistency of beliefs, intentions and reported use.

PubMed

Dye, Huong M; Stanford, Joseph B; Alder, Stephen C; Kim, Han S; Murphy, Patricia A

2005-11-28

This study assesses the consistency of responses among women regarding their beliefs about the mechanisms of actions of birth control methods, beliefs about when human life begins, the intention to use or not use birth control methods that they believe may act after fertilization or implantation, and their reported use of specific methods. A questionnaire was administered in family practice and obstetrics and gynecology clinics in Salt Lake City, Utah, and Tulsa, Oklahoma. Participants included women ages 18-50 presenting for any reason and women under age 18 presenting for family planning or pregnancy care. Analyses were based on key questions addressing beliefs about whether specific birth control methods may act after fertilization, beliefs about when human life begins, intention to use a method that may act after fertilization, and reported use of specific methods. The questionnaire contained no information about the mechanism of action of any method of birth control. Responses were considered inconsistent if actual use contradicted intentions, if one intention contradicted another, or if intentions contradicted beliefs. Of all respondents, 38% gave consistent responses about intention to not use or to stop use of any birth control method that acted after fertilization, while 4% gave inconsistent responses. The corresponding percentages for birth control methods that work after implantation were 64% consistent and 2% inconsistent. Of all respondents, 34% reported they believed that life begins at fertilization and would not use any birth control method that acts after fertilization (a consistent response), while 3% reported they believed that life begins at fertilization but would use a birth control method that acts after fertilization (inconsistent). For specific methods of birth control, less than 1% of women gave inconsistent responses. A majority of women (68% or greater) responded accurately about the mechanism of action of condoms, abstinence, sterilization, and abortion, but a substantial percentage of women (between 19% and 57%) were uncertain about the mechanisms of action of oral contraceptives, intrauterine devices (IUDs), Depo-Provera, or natural family planning. Women who believe that life begins at fertilization may not intend to use a birth control method that could have postfertilization effects. More research is needed to understand the relative importance of postfertilization effects for women in other populations, and in relation to other properties of and priorities for birth control methods. However, many women were uncertain about the mechanisms of action of specific methods. To respect the principles of informed consent, some women may need more education about what is known and not known about the mechanisms of action of birth control methods.

A Robust Cooperated Control Method with Reinforcement Learning and Adaptive H∞ Control

NASA Astrophysics Data System (ADS)

Obayashi, Masanao; Uchiyama, Shogo; Kuremoto, Takashi; Kobayashi, Kunikazu

This study proposes a robust cooperated control method combining reinforcement learning with robust control to control the system. A remarkable characteristic of the reinforcement learning is that it doesn't require model formula, however, it doesn't guarantee the stability of the system. On the other hand, robust control system guarantees stability and robustness, however, it requires model formula. We employ both the actor-critic method which is a kind of reinforcement learning with minimal amount of computation to control continuous valued actions and the traditional robust control, that is, H∞ control. The proposed system was compared method with the conventional control method, that is, the actor-critic only used, through the computer simulation of controlling the angle and the position of a crane system, and the simulation result showed the effectiveness of the proposed method.

Degradation of learned skills: Effectiveness of practice methods on visual approach and landing skill retention

NASA Technical Reports Server (NTRS)

Sitterley, T. E.; Zaitzeff, L. P.; Berge, W. A.

1972-01-01

Flight control and procedural task skill degradation, and the effectiveness of retraining methods were evaluated for a simulated space vehicle approach and landing under instrument and visual flight conditions. Fifteen experienced pilots were trained and then tested after 4 months either without the benefits of practice or with static rehearsal, dynamic rehearsal or with dynamic warmup practice. Performance on both the flight control and procedure tasks degraded significantly after 4 months. The rehearsal methods effectively countered procedure task skill degradation, while dynamic rehearsal or a combination of static rehearsal and dynamic warmup practice was required for the flight control tasks. The quality of the retraining methods appeared to be primarily dependent on the efficiency of visual cue reinforcement.

General algebraic method applied to control analysis of complex engine types

NASA Technical Reports Server (NTRS)

Boksenbom, Aaron S; Hood, Richard

1950-01-01

A general algebraic method of attack on the problem of controlling gas-turbine engines having any number of independent variables was utilized employing operational functions to describe the assumed linear characteristics for the engine, the control, and the other units in the system. Matrices were used to describe the various units of the system, to form a combined system showing all effects, and to form a single condensed matrix showing the principal effects. This method directly led to the conditions on the control system for noninteraction so that any setting disturbance would affect only its corresponding controlled variable. The response-action characteristics were expressed in terms of the control system and the engine characteristics. The ideal control-system characteristics were explicitly determined in terms of any desired response action.

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.

Load controller and method to enhance effective capacity of a photovoltaic power supply using a dynamically determined expected peak loading

DOEpatents

Perez, Richard

2005-05-03

A load controller and method are provided for maximizing effective capacity of a non-controllable, renewable power supply coupled to a variable electrical load also coupled to a conventional power grid. Effective capacity is enhanced by monitoring power output of the renewable supply and loading, and comparing the loading against the power output and a load adjustment threshold determined from an expected peak loading. A value for a load adjustment parameter is calculated by subtracting the renewable supply output and the load adjustment parameter from the current load. This value is then employed to control the variable load in an amount proportional to the value of the load control parameter when the parameter is within a predefined range. By so controlling the load, the effective capacity of the non-controllable, renewable power supply is increased without any attempt at operational feedback control of the renewable supply.

Correcting for batch effects in case-control microbiome studies

PubMed Central

Gibbons, Sean M.; Duvallet, Claire

2018-01-01

High-throughput data generation platforms, like mass-spectrometry, microarrays, and second-generation sequencing are susceptible to batch effects due to run-to-run variation in reagents, equipment, protocols, or personnel. Currently, batch correction methods are not commonly applied to microbiome sequencing datasets. In this paper, we compare different batch-correction methods applied to microbiome case-control studies. We introduce a model-free normalization procedure where features (i.e. bacterial taxa) in case samples are converted to percentiles of the equivalent features in control samples within a study prior to pooling data across studies. We look at how this percentile-normalization method compares to traditional meta-analysis methods for combining independent p-values and to limma and ComBat, widely used batch-correction models developed for RNA microarray data. Overall, we show that percentile-normalization is a simple, non-parametric approach for correcting batch effects and improving sensitivity in case-control meta-analyses. PMID:29684016

Baroreflex control of renal sympathetic nerve activity in early heart failure assessed by the sequence method

PubMed Central

Lataro, Renata Maria; Silva, Luiz Eduardo Virgilio; Silva, Carlos Alberto Aguiar; Salgado, Helio Cesar

2017-01-01

Key points The integrity of the baroreflex control of sympathetic activity in heart failure (HF) remains under debate.We proposed the use of the sequence method to assess the baroreflex control of renal sympathetic nerve activity (RSNA).The sequence method assesses the spontaneous arterial pressure (AP) fluctuations and their related changes in heart rate (or other efferent responses), providing the sensitivity and the effectiveness of the baroreflex. Effectiveness refers to the fraction of spontaneous AP changes that elicits baroreflex‐mediated variations in the efferent response.Using three different approaches, we showed that the baroreflex sensitivity between AP and RSNA is not altered in early HF rats. However, the sequence method provided evidence that the effectiveness of baroreflex in changing RSNA in response to AP changes is markedly decreased in HF.The results help us better understand the baroreflex control of the sympathetic nerve activity. Abstract In heart failure (HF), the reflex control of the heart rate is known to be markedly impaired; however, the baroreceptor control of the sympathetic drive remains under debate. Applying the sequence method to a series of arterial pressure (AP) and renal sympathetic nerve activity (RSNA), we demonstrated a clear dysfunction in the baroreflex control of sympathetic activity in rats with early HF. We analysed the baroreflex control of the sympathetic drive using three different approaches: AP vs. RSNA curve, cross‐spectral analysis and sequence method between AP and RSNA. The sequence method also provides the baroreflex effectiveness index (BEI), which represents the percentage of AP ramps that actually produce a reflex response. The methods were applied to control rats and rats with HF induced by myocardial infarction. None of the methods employed to assess the sympathetic baroreflex gain were able to detect any differences between the control and the HF group. However, rats with HF exhibited a lower BEI compared to the controls. Moreover, an optimum delay of 1 beat was observed, i.e. 1 beat is required for the RSNA to respond after AP changing, which corroborates with the findings related to the timing between these two variables. For delay 1, the BEI of the controls was 0.45 ± 0.03, whereas the BEI of rats with HF was 0.29 ± 0.09 (P < 0.05). These data demonstrate that while the gain of the baroreflex is not affected in early HF, its effectiveness is markedly decreased. The analysis of the spontaneous changes in AP and RSNA using the sequence method provides novel insights into arterial baroreceptor reflex function. PMID:28261799

Sterile-Insect Methods for Control of Mosquito-Borne Diseases: An Analysis

PubMed Central

Benedict, Mark; Bellini, Romeo; Clark, Gary G.; Dame, David A.; Service, Mike W.; Dobson, Stephen L.

2010-01-01

Abstract Effective vector control, and more specifically mosquito control, is a complex and difficult problem, as illustrated by the continuing prevalence (and spread) of mosquito-transmitted diseases. The sterile insect technique and similar methods control certain agricultural insect pest populations in a species-specific, environmentally sound, and effective manner; there is increased interest in applying this approach to vector control. Such an approach, like all others in use and development, is not a one-size-fits-all solution, and will be more appropriate in some situations than others. In addition, the proposed release of pest insects, and more so genetically modified pest insects, is bound to raise questions in the general public and the scientific community as to such a method's efficacy, safety, and sustainability. This article attempts to address these concerns and indicate where sterile-insect methods are likely to be useful for vector control. PMID:19725763

The algorithm for duration acceleration of repetitive projects considering the learning effect

NASA Astrophysics Data System (ADS)

Chen, Hongtao; Wang, Keke; Du, Yang; Wang, Liwan

2018-03-01

Repetitive project optimization problem is common in project scheduling. Repetitive Scheduling Method (RSM) has many irreplaceable advantages in the field of repetitive projects. As the same or similar work is repeated, the proficiency of workers will be correspondingly low to high, and workers will gain experience and improve the efficiency of operations. This is learning effect. Learning effect is one of the important factors affecting the optimization results in repetitive project scheduling. This paper analyzes the influence of the learning effect on the controlling path in RSM from two aspects: one is that the learning effect changes the controlling path, the other is that the learning effect doesn't change the controlling path. This paper proposes corresponding methods to accelerate duration for different types of critical activities and proposes the algorithm for duration acceleration based on the learning effect in RSM. And the paper chooses graphical method to identity activities' types and considers the impacts of the learning effect on duration. The method meets the requirement of duration while ensuring the lowest acceleration cost. A concrete bridge construction project is given to verify the effectiveness of the method. The results of this study will help project managers understand the impacts of the learning effect on repetitive projects, and use the learning effect to optimize project scheduling.

Segregation control in vertical Bridgman crystal growth

NASA Astrophysics Data System (ADS)

Tao, Y.; Kou, S.

1996-11-01

To help the crystal grow at a constant dopant concentration in vertical Bridgman crystal growth, the dopant concentration of the growth melt, i.e. the melt from which the crystal grows, was kept constant. To achieve this, three different methods were used to replenish the growth melt at a controlled rate and suppress dopant diffusion between the growth melt and the replenishing melt. In method one, a replenishing crucible having a long melt passageway was immersed in the growth melt. In method two, a replenishing crucible having an independent feed-rate control mechanism was held above the growth melt. In method three, a submerged diffusion baffle was used to form a long melt passageway between the growth melt and the replenishing melt. NaNO 3 was used as a model material for crystal growth. Single crystals were grown by these three methods with effective segregation control. Method two was applied to InSb and single crystals were also grown with effective segregation control.

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.

Highly Effective Birth Control Use Before and After Women's Incarceration

PubMed Central

Chen, Hsiang-Feng; Cropsey, Karen L.; Clarke, Jennifer G.; Kelly, Patricia J.

2015-01-01

Abstract Background: We examined factors associated with women's use of highly effective birth control before and after incarceration, since women with ongoing criminal justice involvement bear a disproportionate burden of sexual and reproductive health problems, including high rates of unintended pregnancy and inconsistent contraceptive use. Methods: Using a longitudinal study design, we conducted surveys with 102 women in an urban midwestern jail and then followed up with 66 of them 6 months after incarceration. We used stepwise logistic regression to assess individual, interpersonal, resource-based, organizational, and environmental factors associated with utilizing highly effective birth control. Results: Forty-two percent of women reported utilizing highly effective birth control (e.g., sterilization or other highly effective reversible methods) prior to incarceration, and 54% reported using these methods after release from jail (p<0.001). Ninety percent of women reported not wanting to get pregnant. Consistent use of birth control (p=0.001) and alcohol problems (p=0.027) were associated with utilization of highly effective birth control prior to incarceration. Previous pregnancies (p=0.012) were the only factor associated with utilization of highly effective birth control after release from jail. Conclusions: Clinicians and public health practitioners can use findings from this study to develop clinical and intervention efforts aimed at improving unintended-pregnancy prevention among incarcerated women both during their confinement and during the tumultuous period after their release from jail. PMID:25555175

A comparison of treatment effectiveness between the CAD/CAM method and the manual method for managing adolescent idiopathic scoliosis.

PubMed

Wong, M S; Cheng, J C Y; Lo, K H

2005-04-01

The treatment effectiveness of the CAD/CAM method and the manual method in managing adolescent idiopathic scoliosis (AIS) was compared. Forty subjects were recruited with twenty subjects for each method. The clinical parameters namely Cobb's angle and apical vertebral rotation were evaluated at the pre-brace and the immediate in-brace visits. The results demonstrated that orthotic treatments rendered by the CAD/CAM method and the conventional manual method were effective in providing initial control of Cobb's angle. Significant decreases (p < 0.05) were found between the pre-brace and immediate in-brace visits for both methods. The mean reductions of Cobb's angle were 12.8 degrees (41.9%) for the CAD/CAM method and 9.8 degrees (32.1%) for the manual method. An initial control of the apical vertebral rotation was not shown in this study. In the comparison between the CAD/CAM method and the manual method, no significant difference was found in the control of Cobb's angle and apical vertebral rotation. The current study demonstrated that the CAD/CAM method can provide similar result in the initial stage of treatment as compared with the manual method.

Population control methods in stochastic extinction and outbreak scenarios.

PubMed

Segura, Juan; Hilker, Frank M; Franco, Daniel

2017-01-01

Adaptive limiter control (ALC) and adaptive threshold harvesting (ATH) are two related control methods that have been shown to stabilize fluctuating populations. Large variations in population abundance can threaten the constancy and the persistence stability of ecological populations, which may impede the success and efficiency of managing natural resources. Here, we consider population models that include biological mechanisms characteristic for causing extinctions on the one hand and pest outbreaks on the other hand. These models include Allee effects and the impact of natural enemies (as is typical of forest defoliating insects). We study the impacts of noise and different levels of biological parameters in three extinction and two outbreak scenarios. Our results show that ALC and ATH have an effect on extinction and outbreak risks only for sufficiently large control intensities. Moreover, there is a clear disparity between the two control methods: in the extinction scenarios, ALC can be effective and ATH can be counterproductive, whereas in the outbreak scenarios the situation is reversed, with ATH being effective and ALC being potentially counterproductive.

Effects of wingtip modifications on handling qualities of agricultural aircraft

NASA Technical Reports Server (NTRS)

Van Dam, C. P.

1981-01-01

The effect of wingtip modifications on the stability and control characteristics of an agricultural airplane has been studied by means of a nonplanar quasi-vortex-lattice method. The method is used to compute the changes in steady state and perturbed state lateral-directional stability and control derivatives produced by wingtip mounted winglets, vortex diffuser vanes, and tip extensions. The study shows that the combination of the excessive positive dihedral effect produced by the winglets and adverse yaw due to aileron deflection can have a detrimental effect on the roll control characteristics of the airplane. Introduction of an aileron-rudder-interconnect, and reduction of the effective dihedral by canting-in of the winglets, or addition of a lower winglet can eliminate the roll control problems.

A mixed methods approach to assess animal vaccination programmes: The case of rabies control in Bamako, Mali.

PubMed

Mosimann, Laura; Traoré, Abdallah; Mauti, Stephanie; Léchenne, Monique; Obrist, Brigit; Véron, René; Hattendorf, Jan; Zinsstag, Jakob

2017-01-01

In the framework of the research network on integrated control of zoonoses in Africa (ICONZ) a dog rabies mass vaccination campaign was carried out in two communes of Bamako (Mali) in September 2014. A mixed method approach, combining quantitative and qualitative tools, was developed to evaluate the effectiveness of the intervention towards optimization for future scale-up. Actions to control rabies occur on one level in households when individuals take the decision to vaccinate their dogs. However, control also depends on provision of vaccination services and community participation at the intermediate level of social resilience. Mixed methods seem necessary as the problem-driven transdisciplinary project includes epidemiological components in addition to social dynamics and cultural, political and institutional issues. Adapting earlier effectiveness models for health intervention to rabies control, we propose a mixed method assessment of individual effectiveness parameters like availability, affordability, accessibility, adequacy or acceptability. Triangulation of quantitative methods (household survey, empirical coverage estimation and spatial analysis) with qualitative findings (participant observation, focus group discussions) facilitate a better understanding of the weight of each effectiveness determinant, and the underlying reasons embedded in the local understandings, cultural practices, and social and political realities of the setting. Using this method, a final effectiveness of 33% for commune Five and 28% for commune Six was estimated, with vaccination coverage of 27% and 20%, respectively. Availability was identified as the most sensitive effectiveness parameter, attributed to lack of information about the campaign. We propose a mixed methods approach to optimize intervention design, using an "intervention effectiveness optimization cycle" with the aim of maximizing effectiveness. Empirical vaccination coverage estimation is compared to the effectiveness model with its determinants. In addition, qualitative data provide an explanatory framework for deeper insight, validation and interpretation of results which should improve the intervention design while involving all stakeholders and increasing community participation. This work contributes vital information for the optimization and scale-up of future vaccination campaigns in Bamako, Mali. The proposed mixed method, although incompletely applied in this case study, should be applicable to similar rabies interventions targeting elimination in other settings. Copyright © 2016 Elsevier B.V. All rights reserved.

Effective augmentation of networked systems and enhancing pinning controllability

NASA Astrophysics Data System (ADS)

Jalili, Mahdi

2018-06-01

Controlling dynamics of networked systems to a reference state, known as pinning control, has many applications in science and engineering. In this paper, we introduce a method for effective augmentation of networked systems, while also providing high levels of pinning controllability for the final augmented network. The problem is how to connect a sub-network to an already existing network such that the pinning controllability is maximised. We consider the eigenratio of the augmented Laplacian matrix as a pinning controllability metric, and use graph perturbation theory to approximate the influence of edge addition on the eigenratio. The proposed metric can be effectively used to find the inter-network links connecting the disjoint networks. Also, an efficient link rewiring approach is proposed to further optimise the pinning controllability of the augmented network. We provide numerical simulations on synthetic networks and show that the proposed method is more effective than heuristic ones.

Evaluation on the effectiveness of actions for controlling infestation by rodents in Campo Limpo region, Sao Paulo Municipality, Brazil.

PubMed

de Masi, Eduardo; Vilaça, Pedro José; Razzolini, Maria Tereza Pepe

2009-08-01

Rodents are responsible for the transmission of more than 60 diseases both to human beings and to domestic animals. The increase in rodent infestation in a given area brings several health problems to the nearby population. Thus, when infestation increases, it is time to take intervention measures. Although many countries have implemented programs aimed at controlling rodent infestation, literature on studies evaluating the effectiveness of intervention measures in urban areas is scarce. Aimed at contributing to the understanding of rodents' population dynamics in urban areas, the objective of this study was to evaluate the effectiveness of the control methods proposed by "Programa de Vigilancia e Controle de Roedores do Municipio de Sao Paulo" (Program for Rodents Surveillance and Control in Sao Paulo Municipality), conducted on Jardim Comercial District. As a first step, a survey to assess infestation rates was conducted in 1529 dwellings located in the area studied. After that, a chemical control upon rodents was accomplished in every dwelling infested. One week and six months after completion of control measures, a new evaluation on infestation rates was carried out, in order to verify the effectiveness of the procedures taken and to estimate the re-infestation capacity. Initial infestation rate was 40.0%, and the final infestation rate, 14.4%. Therefore, the effectiveness of the control methods utilized was 63.8%. It can thus be concluded that the control methods applied were quite effective.

Women and postfertilization effects of birth control: consistency of beliefs, intentions and reported use

PubMed Central

Dye, Huong M; Stanford, Joseph B; Alder, Stephen C; Kim, Han S; Murphy, Patricia A

2005-01-01

Background This study assesses the consistency of responses among women regarding their beliefs about the mechanisms of actions of birth control methods, beliefs about when human life begins, the intention to use or not use birth control methods that they believe may act after fertilization or implantation, and their reported use of specific methods. Methods A questionnaire was administered in family practice and obstetrics and gynecology clinics in Salt Lake City, Utah, and Tulsa, Oklahoma. Participants included women ages 18–50 presenting for any reason and women under age 18 presenting for family planning or pregnancy care. Analyses were based on key questions addressing beliefs about whether specific birth control methods may act after fertilization, beliefs about when human life begins, intention to use a method that may act after fertilization, and reported use of specific methods. The questionnaire contained no information about the mechanism of action of any method of birth control. Responses were considered inconsistent if actual use contradicted intentions, if one intention contradicted another, or if intentions contradicted beliefs. Results Of all respondents, 38% gave consistent responses about intention to not use or to stop use of any birth control method that acted after fertilization, while 4% gave inconsistent responses. The corresponding percentages for birth control methods that work after implantation were 64% consistent and 2% inconsistent. Of all respondents, 34% reported they believed that life begins at fertilization and would not use any birth control method that acts after fertilization (a consistent response), while 3% reported they believed that life begins at fertilization but would use a birth control method that acts after fertilization (inconsistent). For specific methods of birth control, less than 1% of women gave inconsistent responses. A majority of women (68% or greater) responded accurately about the mechanism of action of condoms, abstinence, sterilization, and abortion, but a substantial percentage of women (between 19% and 57%) were uncertain about the mechanisms of action of oral contraceptives, intrauterine devices (IUDs), Depo-Provera, or natural family planning. Conclusion Women who believe that life begins at fertilization may not intend to use a birth control method that could have postfertilization effects. More research is needed to understand the relative importance of postfertilization effects for women in other populations, and in relation to other properties of and priorities for birth control methods. However, many women were uncertain about the mechanisms of action of specific methods. To respect the principles of informed consent, some women may need more education about what is known and not known about the mechanisms of action of birth control methods. PMID:16313677

Using block pulse functions for seismic vibration semi-active control of structures with MR dampers

NASA Astrophysics Data System (ADS)

Rahimi Gendeshmin, Saeed; Davarnia, Daniel

2018-03-01

This article applied the idea of block pulse functions in the semi-active control of structures. The BP functions give effective tools to approximate complex problems. The applied control algorithm has a major effect on the performance of the controlled system and the requirements of the control devices. In control problems, it is important to devise an accurate analytical technique with less computational cost. It is proved that the BP functions are fundamental tools in approximation problems which have been applied in disparate areas in last decades. This study focuses on the employment of BP functions in control algorithm concerning reduction the computational cost. Magneto-rheological (MR) dampers are one of the well-known semi-active tools that can be used to control the response of civil Structures during earthquake. For validation purposes, numerical simulations of a 5-story shear building frame with MR dampers are presented. The results of suggested method were compared with results obtained by controlling the frame by the optimal control method based on linear quadratic regulator theory. It can be seen from simulation results that the suggested method can be helpful in reducing seismic structural responses. Besides, this method has acceptable accuracy and is in agreement with optimal control method with less computational costs.

Digital redesign of anti-wind-up controller for cascaded analog system.

PubMed

Chen, Y S; Tsai, J S H; Shieh, L S; Moussighi, M M

2003-01-01

The cascaded conventional anti-wind-up (CAW) design method for integral controller is discussed. Then, the prediction-based digital redesign methodology is utilized to find the new pulse amplitude modulated (PAM) digital controller for effective digital control of the analog plant with input saturation constraint. The desired digital controller is determined from existing or pre-designed CAW analog controller. The proposed method provides a novel methodology for indirect digital design of a continuous-time unity output-feedback system with a cascaded analog controller as in the case of PID controllers for industrial control processes with the presence of actuator saturations. It enables us to implement an existing or pre-designed cascaded CAW analog controller via a digital controller effectively.

Integrated pest management and allocation of control efforts for vector-borne diseases

USGS Publications Warehouse

Ginsberg, H.S.

2001-01-01

Applications of various control methods were evaluated to determine how to integrate methods so as to minimize the number of human cases of vector-borne diseases. These diseases can be controlled by lowering the number of vector-human contacts (e.g., by pesticide applications or use of repellents), or by lowering the proportion of vectors infected with pathogens (e.g., by lowering or vaccinating reservoir host populations). Control methods should be combined in such a way as to most efficiently lower the probability of human encounter with an infected vector. Simulations using a simple probabilistic model of pathogen transmission suggest that the most efficient way to integrate different control methods is to combine methods that have the same effect (e.g., combine treatments that lower the vector population; or combine treatments that lower pathogen prevalence in vectors). Combining techniques that have different effects (e.g., a technique that lowers vector populations with a technique that lowers pathogen prevalence in vectors) will be less efficient than combining two techniques that both lower vector populations or combining two techniques that both lower pathogen prevalence, costs being the same. Costs of alternative control methods generally differ, so the efficiency of various combinations at lowering human contact with infected vectors should be estimated at available funding levels. Data should be collected from initial trials to improve the effects of subsequent interventions on the number of human cases.

Hybrid Adaptive Flight Control with Model Inversion Adaptation

NASA Technical Reports Server (NTRS)

Nguyen, Nhan

2011-01-01

This study investigates a hybrid adaptive flight control method as a design possibility for a flight control system that can enable an effective adaptation strategy to deal with off-nominal flight conditions. The hybrid adaptive control blends both direct and indirect adaptive control in a model inversion flight control architecture. The blending of both direct and indirect adaptive control provides a much more flexible and effective adaptive flight control architecture than that with either direct or indirect adaptive control alone. The indirect adaptive control is used to update the model inversion controller by an on-line parameter estimation of uncertain plant dynamics based on two methods. The first parameter estimation method is an indirect adaptive law based on the Lyapunov theory, and the second method is a recursive least-squares indirect adaptive law. The model inversion controller is therefore made to adapt to changes in the plant dynamics due to uncertainty. As a result, the modeling error is reduced that directly leads to a decrease in the tracking error. In conjunction with the indirect adaptive control that updates the model inversion controller, a direct adaptive control is implemented as an augmented command to further reduce any residual tracking error that is not entirely eliminated by the indirect adaptive control.

Active Noise and Vibration Control Literature Survey: Sensors and Actuators

DTIC Science & Technology

1999-08-01

energy from being coupled into the structure of the surface ship or submarine. While t hese methods have proven to be effective in general, there are...3.12 3.5 .3 Sensors Based on the Photo-elastic Effect ......................................... 3 .13 3.6 Electro-reheological Fluids...4.3 4.2.3 Control Methods for Vibration Isolation .............................................. 4.7 4.2.4 Effect of

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.

Modified independent modal space control method for active control of flexible systems

NASA Technical Reports Server (NTRS)

Baz, A.; Poh, S.

1987-01-01

A modified independent modal space control (MIMSC) method is developed for designing active vibration control systems for large flexible structures. The method accounts for the interaction between the controlled and residual modes. It incorporates also optimal placement procedures for selecting the optimal locations of the actuators in the structure in order to minimize the structural vibrations as well as the actuation energy. The MIMSC method relies on an important feature which is based on time sharing of a small number of actuators, in the modal space, to control effectively a large number of modes. Numerical examples are presented to illustrate the application of the method to generic flexible systems. The results obtained suggest the potential of the devised method in designing efficient active control systems for large flexible structures.

Robust backstepping control of an interlink converter in a hybrid AC/DC microgrid based on feedback linearisation method

NASA Astrophysics Data System (ADS)

Dehkordi, N. Mahdian; Sadati, N.; Hamzeh, M.

2017-09-01

This paper presents a robust dc-link voltage as well as a current control strategy for a bidirectional interlink converter (BIC) in a hybrid ac/dc microgrid. To enhance the dc-bus voltage control, conventional methods strive to measure and feedforward the load or source power in the dc-bus control scheme. However, the conventional feedforward-based approaches require remote measurement with communications. Moreover, conventional methods suffer from stability and performance issues, mainly due to the use of the small-signal-based control design method. To overcome these issues, in this paper, the power from DG units of the dc subgrid imposed on the BIC is considered an unmeasurable disturbance signal. In the proposed method, in contrast to existing methods, using the nonlinear model of BIC, a robust controller that does not need the remote measurement with communications effectively rejects the impact of the disturbance signal imposed on the BIC's dc-link voltage. To avoid communication links, the robust controller has a plug-and-play feature that makes it possible to add a DG/load to or remove it from the dc subgrid without distorting the hybrid microgrid stability. Finally, Monte Carlo simulations are conducted to confirm the effectiveness of the proposed control strategy in MATLAB/SimPowerSystems software environment.

The Effectiveness of Robotics as a Manipulative in Mathematics Instruction: A Mixed Method Study

ERIC Educational Resources Information Center

Sheehy, Leonard

2017-01-01

Addition of fractions is an important foundation for students to experience success in mathematics. This mixed-methods study was conducted to measure the effectiveness of robotics as a mathematics manipulative with seventh grade students. Two groups of students were established: control and treatment. The control group received teacher-centered…

Cost-Effectiveness of Aflatoxin Control Methods: Economic Incentives

USDA-ARS?s Scientific Manuscript database

Multiple sectors in U.S. crop industries – growers, elevators, handlers/shellers, processors, distributors, and consumers – are affected by aflatoxin contamination of commodities, and have the potential to control it. Aflatoxin control methods at both preharvest and postharvest levels have been dev...

Load controller and method to enhance effective capacity of a photovoltaic power supply

DOEpatents

Perez, Richard

2000-01-01

A load controller and method are provided for maximizing effective capacity of a non-controllable, renewable power supply coupled to a variable electrical load also coupled to a conventional power grid. Effective capacity is enhanced by monitoring power output of the renewable supply and loading, and comparing the loading against the power output and a load adjustment threshold determined from an expected peak loading. A value for a load adjustment parameter is calculated by subtracting the renewable supply output and the load adjustment parameter from the current load. This value is then employed to control the variable load in an amount proportional to the value of the load control parameter when the parameter is within a predefined range. By so controlling the load, the effective capacity of the non-controllable, renewable power supply is increased without any attempt at operational feedback control of the renewable supply. The renewable supply may comprise, for example, a photovoltaic power supply or a wind-based power supply.

Impulsive control of stochastic systems with applications in chaos control, chaos synchronization, and neural networks.

PubMed

Li, Chunguang; Chen, Luonan; Aihara, Kazuyuki

2008-06-01

Real systems are often subject to both noise perturbations and impulsive effects. In this paper, we study the stability and stabilization of systems with both noise perturbations and impulsive effects. In other words, we generalize the impulsive control theory from the deterministic case to the stochastic case. The method is based on extending the comparison method to the stochastic case. The method presented in this paper is general and easy to apply. Theoretical results on both stability in the pth mean and stability with disturbance attenuation are derived. To show the effectiveness of the basic theory, we apply it to the impulsive control and synchronization of chaotic systems with noise perturbations, and to the stability of impulsive stochastic neural networks. Several numerical examples are also presented to verify the theoretical results.

Estimating the influenza vaccine effectiveness in elderly on a yearly basis using the Spanish influenza surveillance network--pilot case-control studies using different control groups, 2008-2009 season, Spain.

PubMed

Savulescu, Camelia; Valenciano, Marta; de Mateo, Salvador; Larrauri, Amparo

2010-04-01

We conducted a case-control and screening method studies to estimate influenza vaccine effectiveness (IVE) in the age group >or=65 years, based on the Spanish Influenza Sentinel Surveillance System (SISSS). Cases (influenza laboratory-confirmed) were compared to influenza-negative ILI patients (test-negative) and patients without ILI since the beginning of the season (non-ILI). For the screening method, cases' vaccination coverage was compared to the vaccination coverage of the GPs' catchment population. The results suggested a protective effect of the vaccine against laboratory-confirmed influenza in elderly in 2008-2009. The screening method and the test-negative control designs enable estimating IVE using exclusively SISSS data. (c) 2010 Elsevier Ltd. All rights reserved.

Size matters: insights from an allometric approach to evaluate control methods for invasive Australian Rhinella marina.

PubMed

Beaty, Lynne E; Salice, Christopher J

2013-10-01

Invasive species are costly and difficult to control. In order to gain a mechanistic understanding of potential control measures, individual-based models uniquely parameterized to reflect the salient life-history characteristics of invasive species are useful. Using invasive Australian Rhinella marina as a case study, we constructed a cohort- and individual-based population simulation that incorporates growth and body size of terrestrial stages. We used this allometric approach to examine the efficacy of nontraditional control methods (i.e., tadpole alarm chemicals and native meat ants) that may have indirect effects on population dynamics mediated by effects on body size. We compared population estimates resulting from these control methods with traditional hand removal. We also conducted a sensitivity analysis to investigate the effect that model parameters, specifically those associated with growth and body size, had on adult population estimates. Incremental increases in hand removal of adults and juveniles caused nonlinear decreases in adult population estimates, suggesting less return with increased investment in hand-removal efforts. Applying tadpole alarm chemicals or meat ants decreased adult population estimates on the same level as removing 15-25% of adults and juveniles by hand. The combined application of tadpole alarm chemicals and meat ants resulted in approximately 80% decrease in adult abundance, the largest of any applied control method. In further support of the nontraditional control methods, which greatly affected the metamorph stage, our model was most sensitive to changes in metamorph survival, juvenile survival, metamorph growth rate, and adult survival. Our results highlight the use and insights that can be gained from individual-based models that incorporate growth and body size and the potential success that nontraditional control methods could have in controlling established, invasive Rhinella marina populations.

A randomised controlled comparison of injection, thermal, and mechanical endoscopic methods of haemostasis on mesenteric vessels

PubMed Central

Hepworth, C; Kadirkamanathan, S; Gong, F; Swain, C

1998-01-01

Background and aims—A randomised controlled comparison of haemostatic efficacy of mechanical, injection, and thermal methods of haemostasis was undertaken using canine mesenteric vessels to test the hypothesis that mechanical methods of haemostasis are more effective in controlling haemorrhage than injection or thermal methods. The diameter of arteries in human bleeding ulcers measures up to 3.45 mm; mesenteric vessels up to 5 mm were therefore studied. 
Methods—Mesenteric vessels were randomised to treatment with injection sclerotherapy (adrenaline and ethanolamine), bipolar diathermy, or mechanical methods (band, clips, sewing machine, endoloops). The vessels were severed and haemostasis recorded. 
Results—Injection sclerotherapy and clips failed to stop bleeding from vessels of 1 mm (n=20) and 2 mm (n=20). Bipolar diathermy was effective on 8/10 vessels of 2 mm but failed on 3 mm vessels (n=5). Unstretched elastic bands succeeded on 13/15 vessels of 2 mm but on only 3/10 vessels of 3 mm. The sewing machine achieved haemostasis on 8/10 vessels of 4 mm but failed on 5 mm vessels (n=5); endoloops were effective on all 5 mm vessels (n=5). 
Conclusions—Only mechanical methods were effective on vessels greater than 2 mm in diameter. Some mechanical methods (banding and clips) were less effective than expected and need modification. Thermal and (effective) mechanical methods were significantly (p<0.01) more effective than injection sclerotherapy. The most effective mechanical methods were significantly more effective (p<0.01) than thermal or injection on vessels greater than 2mm. 

 Keywords: endoscopic haemostasis; mesenteric vessels PMID:9616305

Control method for physical systems and devices

DOEpatents

Guckenheimer, John

1997-01-01

A control method for stabilizing systems or devices that are outside the control domain of a linear controller is provided. When applied to nonlinear systems, the effectiveness of this method depends upon the size of the domain of stability that is produced for the stabilized equilibrium. If this domain is small compared to the accuracy of measurements or the size of disturbances within the system, then the linear controller is likely to fail within a short period. Failure of the system or device can be catastrophic: the system or device can wander far from the desired equilibrium. The method of the invention presents a general procedure to recapture the stability of a linear controller, when the trajectory of a system or device leaves its region of stability. By using a hybrid strategy based upon discrete switching events within the state space of the system or device, the system or device will return from a much larger domain to the region of stability utilized by the linear controller. The control procedure is robust and remains effective under large classes of perturbations of a given underlying system or device.

Guidelines to birth control counselling of the physically handicapped.

PubMed Central

Szasz, G.; Miller, S.; Anderson, L.

1979-01-01

Birth control counselling of well motivated physically handicapped men and women is discussed in a series of suggested steps: (1) preappointment arrangements are made to ensure physical access to the office, and the partner or a helper may be invited to the visit; (2) the patient is encouraged to name the desired birth control method; (3) the patient's fertility is established from the history and the results of physical examination and laboratory tests; (4) methods of birth control are matched to the patient's physical and mental capabilities; (5) potential side effects of the proposed methods are considered in the light of the handicap; (6) a method is finally recommended that may be a trade-off, with ease of use balanced against efficacy, and living with side effects balanced against the risks of pregnancy; and (7) rechecks are necessary to ensure that the patient is using the method with skill and satisfaction. PMID:156579

Evaluation of Propiconazole Application Methods for Control of Oak Wilt in Texas Live Oaks

Treesearch

A. Dan Wilson; D.G. Lester

1996-01-01

Four fungicide application methods using the microencapsulated (blue) 14.3% EC formulation of propiconazole (Alamo), including a low-concentration high volume method, two high-concentration low volume microinjection methods, and a low-concentration intermediate volume soil drench method, were tested for effectiveness in controlling oak wilt in a mature natural stand of...

Performance assessment of static lead-lag feedforward controllers for disturbance rejection in PID control loops.

PubMed

Yu, Zhenpeng; Wang, Jiandong

2016-09-01

This paper assesses the performance of feedforward controllers for disturbance rejection in univariate feedback plus feedforward control loops. The structures of feedback and feedforward controllers are confined to proportional-integral-derivative and static-lead-lag forms, respectively, and the effects of feedback controllers are not considered. The integral squared error (ISE) and total squared variation (TSV) are used as performance metrics. A performance index is formulated by comparing the current ISE and TSV metrics to their own lower bounds as performance benchmarks. A controller performance assessment (CPA) method is proposed to calculate the performance index from measurements. The proposed CPA method resolves two critical limitations in the existing CPA methods, in order to be consistent with industrial scenarios. Numerical and experimental examples illustrate the effectiveness of the obtained results. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Unsedation colonoscopy can be not that painful: Evaluation of the effect of "Lamaze method of colonoscopy".

PubMed

Yu, Shao-Ping; Lin, Xiao-Dong; Wu, Guang-Yao; Li, Song-Hu; Wen, Zong-Quan; Cen, Xiao-Hong; Huang, Xian-Guang; Huang, Mei-Ting

2015-10-25

To evaluate the pain relieving effect of intervention with "Lamaze method of colonoscopy" in the process of colonoscopy. Five hundred and eighty-five patients underwent colonoscopy were randomly divided into three groups, Lamaze group, anesthetic group and control group. Two hundred and twenty-four patients of Lamaze group, the "Lamaze method of colonoscopy" were practiced in the process of colonoscopy. The Lamaze method of colonoscopy is modified from the Lamaze method of childbirth, which helped patients to relieve pain through effective breathing control. One hundred and seventy-eight patients in anesthetic group accepted sedation colonoscopy. For 183 patients in control group, colonoscopy was performed without any intervention. The satisfactory of colon cleaning, intestinal lesions, intubation time, success ratio, pain grading and complications were recorded. All data were statistically analyzed. There were no significant differences at base line of the three groups (P > 0.05). Anesthetic group shows advantage in intubation time than the other two groups (P < 0.05). Lamaze group shows no advantage in intubation time than that in control group (P > 0.05). The anesthetic group showed an apparent advantage in relieving pain (P < 0.01). Therefore, the "Lamaze method of colonoscopy" performed in colonoscopy could relieve pain effectively comparing with control group (P < 0.05). The patients in anesthetic group had the highest incidence of complications (P < 0.05). The performance of the "Lamaze method of colonoscopy" in the process of colonoscopy could relieve patients' pain, minimize the incidence of complications, and is worthy promotion in clinical practice.

Medroxyprogesterone Injection

MedlinePlus

... Medroxyprogesterone injection is a very effective method of birth control but does not prevent the spread of human ... you have been using a different method of birth control and are switching to medroxyprogesterone injection, your doctor ...

Control Law for Automatic Landing Using Fuzzy Logic Control

NASA Astrophysics Data System (ADS)

Kato, Akio; Inagaki, Yoshiki

The effectiveness of fuzzy logic control law for automatic landing of aircraft, which cover both of control to lead aircraft from level flight at an altitude of 500m to the flight on the glide-path course near the runway and control for the aircraft to land smoothly on a runway, was studied. The control law of the automatic landing was designed to match the design goals of leading from the horizontal flight to the flight on the glide-path course quickly and smoothly and of landing smoothly on a runway. Because there is the ground effect at landing, design of control law and evaluation of control performance were done in consideration of the ground effect. As a result, it was confirmed that the design objective was achieved. Even if the characteristics of the plant changes greatly, this control law was able to maintain the control performance. Moreover, it was confirmed to be able to land safely when there was air turbulence. This paper shows that fuzzy logic control is an effective and flexible method when applied to control law for automatic landing and the design method of control law using fuzzy logic control was obtained.

Experimental research of flow servo-valve

NASA Astrophysics Data System (ADS)

Takosoglu, Jakub

Positional control of pneumatic drives is particularly important in pneumatic systems. Some methods of positioning pneumatic cylinders for changeover and tracking control are known. Choking method is the most development-oriented and has the greatest potential. An optimal and effective method, particularly when applied to pneumatic drives, has been searched for a long time. Sophisticated control systems with algorithms utilizing artificial intelligence methods are designed therefor. In order to design the control algorithm, knowledge about real parameters of servo-valves used in control systems of electro-pneumatic servo-drives is required. The paper presents the experimental research of flow servo-valve.

The effects of different methods of emotional disclosure: differentiating post-traumatic growth from stress symptoms.

PubMed

Slavin-Spenny, Olga M; Cohen, Jay L; Oberleitner, Lindsay M; Lumley, Mark A

2011-10-01

Research on emotional disclosure should test the effects of different disclosure methods and whether symptoms are affected differently than post-traumatic growth. We randomized 214 participants with unresolved stressful experiences to four disclosure conditions (written, private spoken, talking to a passive listener, talking to an active facilitator) or two control conditions. All groups had one 30-minute session. After 6 weeks, disclosure groups reported more post-traumatic growth than controls, and disclosure conditions were similar in this effect. All groups decreased in stress symptoms (intrusions, avoidance, psychological and physical symptoms), but disclosure did not differ from control. We conclude that 30 minutes of disclosure leads to post-traumatic growth but not necessarily symptom reduction, and various disclosure methods have similar effects. Research on the effects of disclosure should focus on the benefits of growth as well as symptom reduction. © 2010 Wiley Periodicals, Inc.

UAV path planning using artificial potential field method updated by optimal control theory

NASA Astrophysics Data System (ADS)

Chen, Yong-bo; Luo, Guan-chen; Mei, Yue-song; Yu, Jian-qiao; Su, Xiao-long

2016-04-01

The unmanned aerial vehicle (UAV) path planning problem is an important assignment in the UAV mission planning. Based on the artificial potential field (APF) UAV path planning method, it is reconstructed into the constrained optimisation problem by introducing an additional control force. The constrained optimisation problem is translated into the unconstrained optimisation problem with the help of slack variables in this paper. The functional optimisation method is applied to reform this problem into an optimal control problem. The whole transformation process is deduced in detail, based on a discrete UAV dynamic model. Then, the path planning problem is solved with the help of the optimal control method. The path following process based on the six degrees of freedom simulation model of the quadrotor helicopters is introduced to verify the practicability of this method. Finally, the simulation results show that the improved method is more effective in planning path. In the planning space, the length of the calculated path is shorter and smoother than that using traditional APF method. In addition, the improved method can solve the dead point problem effectively.

Selection of actuator locations for static shape control of large space structures by heuristic integer programing

NASA Technical Reports Server (NTRS)

Haftka, R. T.; Adelman, H. M.

1984-01-01

Orbiting spacecraft such as large space antennas have to maintain a highly accurate space to operate satisfactorily. Such structures require active and passive controls to mantain an accurate shape under a variety of disturbances. Methods for the optimum placement of control actuators for correcting static deformations are described. In particular, attention is focused on the case were control locations have to be selected from a large set of available sites, so that integer programing methods are called for. The effectiveness of three heuristic techniques for obtaining a near-optimal site selection is compared. In addition, efficient reanalysis techniques for the rapid assessment of control effectiveness are presented. Two examples are used to demonstrate the methods: a simple beam structure and a 55m space-truss-parabolic antenna.

Flight directors for STOl aircraft

NASA Technical Reports Server (NTRS)

Rabin, U. H.

1983-01-01

Flight director logic for flight path and airspeed control of a powered-lift STOL aircraft in the approach, transition, and landing configurations are developed. The methods for flight director design are investigated. The first method is based on the Optimal Control Model (OCM) of the pilot. The second method, proposed here, uses a fixed dynamic model of the pilot in a state space formulation similar to that of the OCM, and includes a pilot work-load metric. Several design examples are presented with various aircraft, sensor, and control configurations. These examples show the strong impact of throttle effectiveness on the performance and pilot work-load associated with manual control of powered-lift aircraft during approach. Improved performed and reduced pilot work-load can be achieved by using direct-lift-control to increase throttle effectiveness.

Estrogen and Progestin (Oral Contraceptives)

MedlinePlus

... from entering. Oral contraceptives are a very effective method of birth control, but they do not prevent ... tell you whether you need to use another method of birth control during the first 7 to ...

Introduction to 2009 Symposium on Alternative Methods of Controlling Pests and Diseases

USDA-ARS?s Scientific Manuscript database

Numerous pests and diseases limit potato productivity, and control of weeds, insects and pathogens remains a costly part of potato production. Although conventional agrichemical pest control is amazingly effective, interest in non-synthetic chemical and integrated methods of pest management is drive...

[Women's behavior and knowledge concerning family planning in the region of the Park Health Center].

PubMed

Ozyurda, F; Durmusoglu, M

1989-01-01

1390 women aged 15-44 were surveyed between February-June 1988 in the vicinity of the Park Health Education Center by the Ankara University School of Medicine, Department of Public Health. Within this sample, the survey focused on the knowledge, attitude and behavior of the 1082 married women, regarding birth control. Birth control pills, IUDs, and condoms were classified as effective modern birth control methods. Other less effective traditional methods were classified as ineffective. Analysis of the data indicated 74.2% of the subjects resort to some form of birth control while 66.2% use an effective modern method. Age, education, work status, number of children and type and location of housing influence family planning decisions. In general, the women using birth control are primary school graduates aged between 25-39, living in urban areas for at least 5 years. Most have 2 to 3 children and have had an abortion. The most frequently used method of birth control is the IUD. It is notable that 29.5% use the ineffective withdrawal method. 58.62% of the women who do not use birth control, avoid family planning because of their husbands. These women have 2 or more children and are illiterate or primary school graduates between the ages of 25-35 when they are most likely to become pregnant. Family planning services should be geared towards educating these families, especially the husbands. Education services should also target families using the withdrawal method and the 35-44 age group of women who show a low percentage of contraceptive use.

Ethinyl Estradiol and Etonogestrel Vaginal Ring

MedlinePlus

... entering. The contraceptive ring is a very effective method of birth control but does not prevent the ... cases, you may need to use an additional method of birth control for the first seven days ...

Progestin-Only Oral Contraceptives

MedlinePlus

... oral contraceptives are a very effective method of birth control, but they do not prevent the spread of ... on another day, use a backup method of birth control (such as a condom and/or a spermicide) ...

The effectiveness of faecal removal methods of pasture management to control the cyathostomin burden of donkeys

PubMed Central

2014-01-01

Background The level of anthelmintic resistance within some cyathostomin parasite populations has increased to the level where sole reliance on anthelmintic-based control protocols is not possible. Management-based nematode control methods, including removal of faeces from pasture, are widely recommended for use in association with a reduction in anthelmintic use to reduce selection pressure for drug resistance; however, very little work has been performed to quantitatively assess the effectiveness of such methods. Methods We analysed data obtained from 345 donkeys at The Donkey Sanctuary (Devon, UK), managed under three different pasture management techniques, to investigate the effectiveness of faeces removal in strongyle control in equids. The management groups were as follows: no removal of faeces from pasture, manual, twice-weekly removal of faeces from pasture and automatic, twice-weekly removal of faeces from pasture (using a mechanical pasture sweeper). From turn-out onto pasture in May, monthly faecal egg counts were obtained for each donkey and the dataset subjected to an auto regressive moving average model. Results There was little to no difference in faecal egg counts between the two methods of faecal removal; both resulted in significantly improved cyathostomin control compared to the results obtained from the donkeys that grazed pasture from which there was no faecal removal. Conclusions This study represents a valuable and unique assessment of the effectiveness of the removal of equine faeces from pasture, and provides an evidence base from which to advocate twice-weekly removal of faeces from pasture as an adjunct for equid nematode control. Widespread adoption of this practice could substantially reduce anthelmintic usage, and hence reduce selection pressure for nematode resistance to the currently effective anthelmintic products. PMID:24460700

Real-time implementation of model predictive control on Maricopa-Stanfield irrigation and drainage district's WM canal

USDA-ARS?s Scientific Manuscript database

Water resources are limited in many agricultural areas. One method to improve the effective use of water is to improve delivery service from irrigation canals. This can be done by applying automatic control methods that control the gates in an irrigation canal. The model predictive control MPC is ...

Composite synchronization of three eccentric rotors driven by induction motors in a vibrating system

NASA Astrophysics Data System (ADS)

Kong, Xiangxi; Chen, Changzheng; Wen, Bangchun

2018-03-01

This paper addresses the problem of composite synchronization of three eccentric rotors (ERs) driven by induction motors in a vibrating system. The composite synchronous motion of three ERs is composed of the controlled synchronous motion of two ERs and the self-synchronous motion of the third ER. Combining an adaptive sliding mode control (ASMC) algorithm with a modified master-slave control structure, the controllers are designed to implement controlled synchronous motion of two ERs with zero phase difference. Based on Lyapunov stability theorem and Barbalat's lemma, the stability of the designed controllers is verified. On basis of controlled synchronization of two ERs, self-synchronization of the third ER is introduced to implement composite synchronous motion of three ERs. The feasibility of the proposed composite synchronization method is analyzed by numerical method. The effects of motor and structure parameters on composite synchronous motion are discussed. Experiments on a vibrating test bench driven by three ERs are operated to validate the effectiveness of the proposed composite synchronization method, including a comparison with self-synchronization method.

Estimation of effectiveness of interventions for malaria control in pregnancy using the screening method.

PubMed

Msyamboza, K; Senga, E; Tetteh-Ashong, E; Kazembe, P; Brabin, B J

2007-04-01

The evaluation of the effectiveness of antimalarial drugs and bed net use in pregnant women is an important aspect of monitoring and surveillance of malaria control in pregnancy. In principle the screening method for assessing vaccine efficacy can be applied in non-vaccine settings for assessing interventions for malaria control in pregnancy. In this analysis field data on the proportion of placental malaria cases treated with two doses of sulphadoxine-pyrimethamine (SP) and the uptake of two doses of SP in the antenatal clinic was used in a case-coverage method to assess the protective effectiveness (PE) of intermittent preventive treatment with SP for malaria control in pregnancy. PE was assessed using placental malaria, low birthweight and maternal anaemia at delivery as outcome variables. The method was also applied to an evaluation of the protective effectiveness of self-reported use of impregnated bed nets (ITNs). Effectiveness was highest for reduction of low birthweight in multigravidae (87.2%, 95% CI, 83.2-91.3%). PE was lower for placental malaria (61.6% primigravidae, 28.5% multigravidae), and maternal anaemia (Hb < 8.0 g/dl, 37.8% primigravidae, 29.6% multigravidae). Estimates for PE of self-reported use of ITNs gave values for all three outcome parameters that were much lower than for SP use. For women of all parties effectiveness estimates for reduction of low birthweight were 22% (95% CI, 17.7-26.4), prevention of placental malaria (all types) 7.1% (95% CI, 4.4-9.8), prevention of active placental infection 38.9% (95% CI, 27.4-50.4), and for maternal anaemia 8.8% (95% CI, 0-20.0). The case-coverage method could provide a useful and practical approach to routine monitoring and evaluation of drug interventions to control malaria in pregnancy and has potentially wide applications. Effectiveness estimates related to reported ITN use in pregnancy may be less reliable. The method should be further evaluated using currently available data sets.

A Design Method for a State Feedback Microcomputer Controller of a Wide Bandwidth Analog Plant.

DTIC Science & Technology

1983-12-01

Il IIIz NAVAL POSTGRADUATE SCHOOLMonterey, California THESIS A A DESIGN METHOD FOR A STATE FEEDBACK MICROCOMPUTER CONTROLLER OF A WIDE BANDWIDTH...of a microcomputer regulator, continuous or discrete method can be applied. The o:bjective of this thesis is to provide a continuous controller ...estimation and control type problem. In this thesis , a wide bandwidth analog computer system is chosen as the plant so that the effect of transport

Epidemiology and control of east coast fever in Zambia. A field trial with traditionally managed Sanga cattle.

PubMed

Minjauw, B; Otte, M J; James, A D

1998-06-29

The main objective of the reported field trial was to compare different East Coast Fever (ECF) control strategies for their efficacy, effect on cattle productivity and cost-effectiveness. Five strategies were tested in groups of traditionally managed Sanga cattle over a period of 2.5 years. Two groups were under intensive tick control, one group immunized by the infection and treatment method and the other non-immunized. Two groups were under no tick control, one group immunized and the other non-immunized (the control group). The fifth group was under strategic tick control and was immunized against ECF. All ECF control methods tested significantly reduced mortality, but no marked differences to the control group were seen in other production parameters. No difference in mortality was observed between animals protected from ECF by immunization or by tick control. The most cost-effective method of controlling the disease was by immunization. A financial analysis showed that under the prevailing conditions the break-even price for immunization ranged from US$21.5 to US$25.7 depending of the proportion of reactors. The carrier state induced by immunization did not lead to a persistent high incidence of ECF in non-immunized animals using the same grazing area.

Coordinated control of active and reactive power of distribution network with distributed PV cluster via model predictive control

NASA Astrophysics Data System (ADS)

Ji, Yu; Sheng, Wanxing; Jin, Wei; Wu, Ming; Liu, Haitao; Chen, Feng

2018-02-01

A coordinated optimal control method of active and reactive power of distribution network with distributed PV cluster based on model predictive control is proposed in this paper. The method divides the control process into long-time scale optimal control and short-time scale optimal control with multi-step optimization. The models are transformed into a second-order cone programming problem due to the non-convex and nonlinear of the optimal models which are hard to be solved. An improved IEEE 33-bus distribution network system is used to analyse the feasibility and the effectiveness of the proposed control method

Sliding-mode control combined with improved adaptive feedforward for wafer scanner

NASA Astrophysics Data System (ADS)

Li, Xiaojie; Wang, Yiguang

2018-03-01

In this paper, a sliding-mode control method combined with improved adaptive feedforward is proposed for wafer scanner to improve the tracking performance of the closed-loop system. Particularly, In addition to the inverse model, the nonlinear force ripple effect which may degrade the tracking accuracy of permanent magnet linear motor (PMLM) is considered in the proposed method. The dominant position periodicity of force ripple is determined by using the Fast Fourier Transform (FFT) analysis for experimental data and the improved feedforward control is achieved by the online recursive least-squares (RLS) estimation of the inverse model and the force ripple. The improved adaptive feedforward is given in a general form of nth-order model with force ripple effect. This proposed method is motivated by the motion controller design of the long-stroke PMLM and short-stroke voice coil motor for wafer scanner. The stability of the closed-loop control system and the convergence of the motion tracking are guaranteed by the proposed sliding-mode feedback and adaptive feedforward methods theoretically. Comparative experiments on a precision linear motion platform can verify the correctness and effectiveness of the proposed method. The experimental results show that comparing to traditional method the proposed one has better performance of rapidity and robustness, especially for high speed motion trajectory. And, the improvements on both tracking accuracy and settling time can be achieved.

Current Methods for Modeling and Simulating Icing Effects on Aircraft Performance, Stability and Control

NASA Technical Reports Server (NTRS)

Ralvasky, Thomas P.; Barnhart, Billy P.; Lee, Sam

2008-01-01

Icing alters the shape and surface characteristics of aircraft components, which results in altered aerodynamic forces and moments caused by air flow over those iced components. The typical effects of icing are increased drag, reduced stall angle of attack, and reduced maximum lift. In addition to the performance changes, icing can also affect control surface effectiveness, hinge moments, and damping. These effects result in altered aircraft stability and control and flying qualities. Over the past 80 years, methods have been developed to understand how icing affects performance, stability and control. Emphasis has been on wind tunnel testing of two-dimensional subscale airfoils with various ice shapes to understand their effect on the flow field and ultimately the aerodynamics. This research has led to wind tunnel testing of subscale complete aircraft models to identify the integrated effects of icing on the aircraft system in terms of performance, stability, and control. Data sets of this nature enable pilot in the loop simulations to be performed for pilot training, or engineering evaluation of system failure impacts or control system design.

Current Methods Modeling and Simulating Icing Effects on Aircraft Performance, Stability, Control

NASA Technical Reports Server (NTRS)

Ratvasky, Thomas P.; Barnhart, Billy P.; Lee, Sam

2010-01-01

Icing alters the shape and surface characteristics of aircraft components, which results in altered aerodynamic forces and moments caused by air flow over those iced components. The typical effects of icing are increased drag, reduced stall angle of attack, and reduced maximum lift. In addition to the performance changes, icing can also affect control surface effectiveness, hinge moments, and damping. These effects result in altered aircraft stability and control and flying qualities. Over the past 80 years, methods have been developed to understand how icing affects performance, stability, and control. Emphasis has been on wind-tunnel testing of two-dimensional subscale airfoils with various ice shapes to understand their effect on the flowfield and ultimately the aerodynamics. This research has led to wind-tunnel testing of subscale complete aircraft models to identify the integrated effects of icing on the aircraft system in terms of performance, stability, and control. Data sets of this nature enable pilot-in-the-loop simulations to be performed for pilot training or engineering evaluation of system failure impacts or control system design.

A comparison between IMSC, PI and MIMSC methods in controlling the vibration of flexible systems

NASA Technical Reports Server (NTRS)

Baz, A.; Poh, S.

1987-01-01

A comparative study is presented between three active control algorithms which have proven to be successful in controlling the vibrations of large flexible systems. These algorithms are: the Independent Modal Space Control (IMSC), the Pseudo-inverse (PI), and the Modified Independent Modal Space Control (MIMSC). Emphasis is placed on demonstrating the effectiveness of the MIMSC method in controlling the vibration of large systems with small number of actuators by using an efficient time sharing strategy. Such a strategy favors the MIMSC over the IMSC method, which requires a large number of actuators to control equal number of modes, and also over the PI method which attempts to control large number of modes with smaller number of actuators through the use of an in-exact statistical realization of a modal controller. Numerical examples are presented to illustrate the main features of the three algorithms and the merits of the MIMSC method.

Exploring effective multiplicity in multichannel functional near-infrared spectroscopy using eigenvalues of correlation matrices

PubMed Central

Uga, Minako; Dan, Ippeita; Dan, Haruka; Kyutoku, Yasushi; Taguchi, Y-h; Watanabe, Eiju

2015-01-01

Abstract. Recent advances in multichannel functional near-infrared spectroscopy (fNIRS) allow wide coverage of cortical areas while entailing the necessity to control family-wise errors (FWEs) due to increased multiplicity. Conventionally, the Bonferroni method has been used to control FWE. While Type I errors (false positives) can be strictly controlled, the application of a large number of channel settings may inflate the chance of Type II errors (false negatives). The Bonferroni-based methods are especially stringent in controlling Type I errors of the most activated channel with the smallest p value. To maintain a balance between Types I and II errors, effective multiplicity (Meff) derived from the eigenvalues of correlation matrices is a method that has been introduced in genetic studies. Thus, we explored its feasibility in multichannel fNIRS studies. Applying the Meff method to three kinds of experimental data with different activation profiles, we performed resampling simulations and found that Meff was controlled at 10 to 15 in a 44-channel setting. Consequently, the number of significantly activated channels remained almost constant regardless of the number of measured channels. We demonstrated that the Meff approach can be an effective alternative to Bonferroni-based methods for multichannel fNIRS studies. PMID:26157982

Mode tuning of a simplified string instrument using time-dimensionless state-derivative control

NASA Astrophysics Data System (ADS)

Benacchio, Simon; Chomette, Baptiste; Mamou-Mani, Adrien; Finel, Victor

2015-01-01

In recent years, there has been a growing interest in smart structures, particularly in the field of musical acoustics. Control methods, initially developed to reduce vibration and damage, can be a good way to shift modal parameters of a structure in order to modify its dynamic response. This study focuses on smart musical instruments and aims to modify their radiated sound. This is achieved by controlling the modal parameters of the soundboard of a simplified string instrument. A method combining a pole placement algorithm and a time-dimensionless state-derivative control is used and quickly compared to a usual state control method. Then the effect of the mode tuning on the coupling between the string and the soundboard is experimentally studied. Controlling two vibration modes of the soundboard, its acoustic response and the damping of the third partial of the sound are modified. Finally these effects are listened in the radiated sound.

Remotely controlling of mobile robots using gesture captured by the Kinect and recognized by machine learning method

NASA Astrophysics Data System (ADS)

Hsu, Roy CHaoming; Jian, Jhih-Wei; Lin, Chih-Chuan; Lai, Chien-Hung; Liu, Cheng-Ting

2013-01-01

The main purpose of this paper is to use machine learning method and Kinect and its body sensation technology to design a simple, convenient, yet effective robot remote control system. In this study, a Kinect sensor is used to capture the human body skeleton with depth information, and a gesture training and identification method is designed using the back propagation neural network to remotely command a mobile robot for certain actions via the Bluetooth. The experimental results show that the designed mobile robots remote control system can achieve, on an average, more than 96% of accurate identification of 7 types of gestures and can effectively control a real e-puck robot for the designed commands.

Feedback control for unsteady flow and its application to the stochastic Burgers equation

NASA Technical Reports Server (NTRS)

Choi, Haecheon; Temam, Roger; Moin, Parviz; Kim, John

1993-01-01

The study applies mathematical methods of control theory to the problem of control of fluid flow with the long-range objective of developing effective methods for the control of turbulent flows. Model problems are employed through the formalism and language of control theory to present the procedure of how to cast the problem of controlling turbulence into a problem in optimal control theory. Methods of calculus of variations through the adjoint state and gradient algorithms are used to present a suboptimal control and feedback procedure for stationary and time-dependent problems. Two types of controls are investigated: distributed and boundary controls. Several cases of both controls are numerically simulated to investigate the performances of the control algorithm. Most cases considered show significant reductions of the costs to be minimized. The dependence of the control algorithm on the time-descretization method is discussed.

Trajectory control method of stratospheric airship based on the sliding mode control and prediction in wind field

NASA Astrophysics Data System (ADS)

Zhang, Jia-shi; Yang, Xi-xiang

2017-11-01

The stratospheric airship has the characteristics of large inertia, long time delay and large disturbance of wind field , so the trajectory control is very difficult .Build the lateral three degrees of freedom dynamic model which consider the wind interference , the dynamics equation is linearized by the small perturbation theory, propose a trajectory control method Combine with the sliding mode control and prediction, design the trajectory controller , takes the HAA airship as the reference to carry out simulation analysis. Results show that the improved sliding mode control with front-feedback method not only can solve well control problems of airship trajectory in wind field, but also can effectively improve the control accuracy of the traditional sliding mode control method, solved problems that using the traditional sliding mode control to control. It provides a useful reference for dynamic modeling and trajectory control of stratospheric airship.

Case-control vaccine effectiveness studies: Data collection, analysis and reporting results.

PubMed

Verani, Jennifer R; Baqui, Abdullah H; Broome, Claire V; Cherian, Thomas; Cohen, Cheryl; Farrar, Jennifer L; Feikin, Daniel R; Groome, Michelle J; Hajjeh, Rana A; Johnson, Hope L; Madhi, Shabir A; Mulholland, Kim; O'Brien, Katherine L; Parashar, Umesh D; Patel, Manish M; Rodrigues, Laura C; Santosham, Mathuram; Scott, J Anthony; Smith, Peter G; Sommerfelt, Halvor; Tate, Jacqueline E; Victor, J Chris; Whitney, Cynthia G; Zaidi, Anita K; Zell, Elizabeth R

2017-06-05

The case-control methodology is frequently used to evaluate vaccine effectiveness post-licensure. The results of such studies provide important insight into the level of protection afforded by vaccines in a 'real world' context, and are commonly used to guide vaccine policy decisions. However, the potential for bias and confounding are important limitations to this method, and the results of a poorly conducted or incorrectly interpreted case-control study can mislead policies. In 2012, a group of experts met to review recent experience with case-control studies evaluating vaccine effectiveness; we summarize the recommendations of that group regarding best practices for data collection, analysis, and presentation of the results of case-control vaccine effectiveness studies. Vaccination status is the primary exposure of interest, but can be challenging to assess accurately and with minimal bias. Investigators should understand factors associated with vaccination as well as the availability of documented vaccination status in the study context; case-control studies may not be a valid method for evaluating vaccine effectiveness in settings where many children lack a documented immunization history. To avoid bias, it is essential to use the same methods and effort gathering vaccination data from cases and controls. Variables that may confound the association between illness and vaccination are also important to capture as completely as possible, and where relevant, adjust for in the analysis according to the analytic plan. In presenting results from case-control vaccine effectiveness studies, investigators should describe enrollment among eligible cases and controls as well as the proportion with no documented vaccine history. Emphasis should be placed on confidence intervals, rather than point estimates, of vaccine effectiveness. Case-control studies are a useful approach for evaluating vaccine effectiveness; however careful attention must be paid to the collection, analysis and presentation of the data in order to best inform evidence-based vaccine policies. Published by Elsevier Ltd.

Approximation methods for control of structural acoustics models with piezoceramic actuators

NASA Astrophysics Data System (ADS)

Banks, H. T.; Fang, W.; Silcox, R. J.; Smith, R. C.

1993-01-01

The active control of acoustic pressure in a 2-D cavity with a flexible boundary (a beam) is considered. Specifically, this control is implemented via piezoceramic patches on the beam which produces pure bending moments. The incorporation of the feedback control in this manner leads to a system with an unbounded input term. Approximation methods in this manner leads to a system with an unbounded input term. Approximation methods in this manner leads to a system with an unbounded input team. Approximation methods in the context of linear quadratic regulator (LQR) state space control formulation are discussed and numerical results demonstrating the effectiveness of this approach in computing feedback controls for noise reduction are presented.

One shot methods for optimal control of distributed parameter systems 1: Finite dimensional control

NASA Technical Reports Server (NTRS)

Taasan, Shlomo

1991-01-01

The efficient numerical treatment of optimal control problems governed by elliptic partial differential equations (PDEs) and systems of elliptic PDEs, where the control is finite dimensional is discussed. Distributed control as well as boundary control cases are discussed. The main characteristic of the new methods is that they are designed to solve the full optimization problem directly, rather than accelerating a descent method by an efficient multigrid solver for the equations involved. The methods use the adjoint state in order to achieve efficient smoother and a robust coarsening strategy. The main idea is the treatment of the control variables on appropriate scales, i.e., control variables that correspond to smooth functions are solved for on coarse grids depending on the smoothness of these functions. Solution of the control problems is achieved with the cost of solving the constraint equations about two to three times (by a multigrid solver). Numerical examples demonstrate the effectiveness of the method proposed in distributed control case, pointwise control and boundary control problems.

A novel pre-control method of vehicle dynamics stability based on critical stable velocity during transient steering maneuvering

NASA Astrophysics Data System (ADS)

Chen, Jie; Song, Jian; Li, Liang; Ran, Xu; Jia, Gang; Wu, Kaihui

2016-05-01

The current research of direct yaw moment control (DYC) system focus on the design of target yaw moment and the distribution of wheel brake force. The differential braking intervention can effectively improve the lateral stability of the vehicle, however, the effect of DYC can be improved a step further by applying the control of vehicle longitudinal velocity. In this paper, the relationship between the vehicle longitudinal velocity and lateral stability is studied, and the simulation results show that a decrease of 5 km/h of longitudinal velocity at a particular situation can bring 100° increasing of stable steering upper limit. A critical stable velocity considering the effect of steering and yaw rate measurement is defined to evaluate the risk of losing steer-ability or stability. A novel velocity pre-control method is proposed by using a hierarchical pre-control logic and is integrated with the traditional DYC system. The control algorithm is verified through a hardware in-the-loop simulation system. Double lane change (DLC) test results on both high friction coefficient (μ) and low μ roads show that by using the pre-control method, the steering effort in DLC test can be reduced by 38% and 51% and the peak value of brake pressure control can be reduced by 20% and 12% respectively on high μ and low μ roads, the lateral stability is also improved. This research proposes a novel DYC system with lighter control effort and better control effect.

Interrupted Time Series Versus Statistical Process Control in Quality Improvement Projects.

PubMed

Andersson Hagiwara, Magnus; Andersson Gäre, Boel; Elg, Mattias

2016-01-01

To measure the effect of quality improvement interventions, it is appropriate to use analysis methods that measure data over time. Examples of such methods include statistical process control analysis and interrupted time series with segmented regression analysis. This article compares the use of statistical process control analysis and interrupted time series with segmented regression analysis for evaluating the longitudinal effects of quality improvement interventions, using an example study on an evaluation of a computerized decision support system.

Structured output-feedback controller synthesis with design specifications

NASA Astrophysics Data System (ADS)

Hao, Yuqing; Duan, Zhisheng

2017-03-01

This paper considers the problem of structured output-feedback controller synthesis with finite frequency specifications. Based on the orthogonal space information of input matrix, an improved parameter-dependent Lyapunov function method is first proposed. Then, a two-stage construction method is designed, which depends on an initial centralised controller. Corresponding design conditions for three types of output-feedback controllers are presented in terms of unified representations. Moreover, heuristic algorithms are provided to explore the desirable controllers. Finally, the effectiveness of these proposed methods is illustrated via some practical examples.

Optimal control of 2-wheeled mobile robot at energy performance index

NASA Astrophysics Data System (ADS)

Kaliński, Krzysztof J.; Mazur, Michał

2016-03-01

The paper presents the application of the optimal control method at the energy performance index towards motion control of the 2-wheeled mobile robot. With the use of the proposed method of control the 2-wheeled mobile robot can realise effectively the desired trajectory. The problem of motion control of mobile robots is usually neglected and thus performance of the realisation of the high level control tasks is limited.

Evaluation of effectiveness of combined sewer overflow control measures by operational data.

PubMed

Schroeder, K; Riechel, M; Matzinger, A; Rouault, P; Sonnenberg, H; Pawlowsky-Reusing, E; Gnirss, R

2011-01-01

The effect of combined sewer overflow (CSO) control measures should be validated during operation based on monitoring of CSO activity and subsequent comparison with (legal) requirements. However, most CSO monitoring programs have been started only recently and therefore no long-term data is available for reliable efficiency control. A method is proposed that focuses on rainfall data for evaluating the effectiveness of CSO control measures. It is applicable if a sufficient time-series of rainfall data and a limited set of data on CSO discharges are available. The method is demonstrated for four catchments of the Berlin combined sewer system. The analysis of the 2000-2007 data shows the effect of CSO control measures, such as activation of in-pipe storage capacities within the Berlin system. The catchment, where measures are fully implemented shows less than 40% of the CSO activity of those catchments, where measures have not yet or not yet completely been realised.

A Method to Quantify the Wind and Non-wind Contribution to Year-to-year Air Quality Variation and its Application in China

NASA Astrophysics Data System (ADS)

LI, Y.; Lau, A. K. H.; Wong, A.; Fung, J. C. H.

2017-12-01

Changes in emissions and wind are often identified as the two dominant factors contributing to year-to-year variations in the concentration of primary pollutants. However, because changes in wind and emissions are intertwined, it has been difficult to quantitatively differentiate their effects on air quality directly from observed data. In particular, if the annual mean concentration of pollutants is higher than the previous year, it is difficult to identify whether the deterioration in air quality is caused by wind blowing from more polluted regions or an increase in contributing emissions. In this paper, based on wind and pollution roses, we propose a method to differentiate the effects of wind and non-wind (e.g., emissions) changes using direct observation. An index (L) is first defined to quantify the validity of the linear decomposition. The method is then validated by idealized experiments, numerical experiments and a two-year observation dataset from an actual emissions control program. Finally, we demonstrate the proposed method by studying long-term PM10 variations in Hong Kong during 2000-2011. We find that for most of the period, the linear decomposition of the changes in annual PM10 is valid (up to 90% confidence) and is dominated by the change in non-wind effects (e.g., emissions), whereas the average absolute effect from the wind variability is about 20%. Sensitivity analyses also suggest that our method should work in any location as long as the observed wind and pollution data have sufficient duration and resolution to resolve the corresponding wind and pollution roses. The method is applied for estimating the control effectiveness of the intervention programs in the Shanghai Expo, the longest socioeconomic international event held in China. The results show that integrated effect of control policies taken for improving the air quality in Shanghai are significantly effective for PM10 reduction and also effective for SO2 reduction, whereas the traffic emission control are not effective for NO2 at urban stations, though the overall emission control lead to an decrease for the city average NO2 concentration.

Rock sampling. [method for controlling particle size distribution

NASA Technical Reports Server (NTRS)

Blum, P. (Inventor)

1971-01-01

A method for sampling rock and other brittle materials and for controlling resultant particle sizes is described. The method involves cutting grooves in the rock surface to provide a grouping of parallel ridges and subsequently machining the ridges to provide a powder specimen. The machining step may comprise milling, drilling, lathe cutting or the like; but a planing step is advantageous. Control of the particle size distribution is effected primarily by changing the height and width of these ridges. This control exceeds that obtainable by conventional grinding.

Load controller and method to enhance effective capacity of a photovotaic power supply using a dynamically determined expected peak loading

DOEpatents

Perez, Richard

2003-04-01

A load controller and method are provided for maximizing effective capacity of a non-controllable, renewable power supply coupled to a variable electrical load also coupled to a conventional power grid. Effective capacity is enhanced by monitoring power output of the renewable supply and loading, and comparing the loading against the power output and a load adjustment threshold determined from an expected peak loading. A value for a load adjustment parameter is calculated by subtracting the renewable supply output and the load adjustment parameter from the current load. This value is then employed to control the variable load in an amount proportional to the value of the load control parameter when the parameter is within a predefined range. By so controlling the load, the effective capacity of the non-controllable, renewable power supply is increased without any attempt at operational feedback control of the renewable supply. The expected peak loading of the variable load can be dynamically determined within a defined time interval with reference to variations in the variable load.

Adaptive control for solar energy based DC microgrid system development

NASA Astrophysics Data System (ADS)

Zhang, Qinhao

During the upgrading of current electric power grid, it is expected to develop smarter, more robust and more reliable power systems integrated with distributed generations. To realize these objectives, traditional control techniques are no longer effective in either stabilizing systems or delivering optimal and robust performances. Therefore, development of advanced control methods has received increasing attention in power engineering. This work addresses two specific problems in the control of solar panel based microgrid systems. First, a new control scheme is proposed for the microgrid systems to achieve optimal energy conversion ratio in the solar panels. The control system can optimize the efficiency of the maximum power point tracking (MPPT) algorithm by implementing two layers of adaptive control. Such a hierarchical control architecture has greatly improved the system performance, which is validated through both mathematical analysis and computer simulation. Second, in the development of the microgrid transmission system, the issues related to the tele-communication delay and constant power load (CPL)'s negative incremental impedance are investigated. A reference model based method is proposed for pole and zero placements that address the challenges of the time delay and CPL in closed-loop control. The effectiveness of the proposed modeling and control design methods are demonstrated in a simulation testbed. Practical aspects of the proposed methods for general microgrid systems are also discussed.

An improved design method of a tuned mass damper for an in-service footbridge

NASA Astrophysics Data System (ADS)

Shi, Weixing; Wang, Liangkun; Lu, Zheng

2018-03-01

Tuned mass damper (TMD) has a wide range of applications in the vibration control of footbridges. However, the traditional engineering design method may lead to a mistuned TMD. In this paper, an improved TMD design method based on the model updating is proposed. Firstly, the original finite element model (FEM) is studied and the natural characteristics of the in-service or newly built footbridge is identified by field test, and then the original FEM is updated. TMD is designed according to the new updated FEM, and it is optimized according to the simulation on vibration control effects. Finally, the installation and field measurement of TMD are carried out. The improved design method can be applied to both in-service and newly built footbridges. This paper illustrates the improved design method with an engineering example. The frequency identification results of field test and original FEM show that there is a relatively large difference between them. The TMD designed according to the updated FEM has better vibration control effect than the TMD designed according to the original FEM. The site test results show that TMD has good effect on controlling human-induced vibrations.

An Adaptive Instability Suppression Controls Method for Aircraft Gas Turbine Engine Combustors

NASA Technical Reports Server (NTRS)

Kopasakis, George; DeLaat, John C.; Chang, Clarence T.

2008-01-01

An adaptive controls method for instability suppression in gas turbine engine combustors has been developed and successfully tested with a realistic aircraft engine combustor rig. This testing was part of a program that demonstrated, for the first time, successful active combustor instability control in an aircraft gas turbine engine-like environment. The controls method is called Adaptive Sliding Phasor Averaged Control. Testing of the control method has been conducted in an experimental rig with different configurations designed to simulate combustors with instabilities of about 530 and 315 Hz. Results demonstrate the effectiveness of this method in suppressing combustor instabilities. In addition, a dramatic improvement in suppression of the instability was achieved by focusing control on the second harmonic of the instability. This is believed to be due to a phenomena discovered and reported earlier, the so called Intra-Harmonic Coupling. These results may have implications for future research in combustor instability control.

Adaptive Importance Sampling for Control and Inference

NASA Astrophysics Data System (ADS)

Kappen, H. J.; Ruiz, H. C.

2016-03-01

Path integral (PI) control problems are a restricted class of non-linear control problems that can be solved formally as a Feynman-Kac PI and can be estimated using Monte Carlo sampling. In this contribution we review PI control theory in the finite horizon case. We subsequently focus on the problem how to compute and represent control solutions. We review the most commonly used methods in robotics and control. Within the PI theory, the question of how to compute becomes the question of importance sampling. Efficient importance samplers are state feedback controllers and the use of these requires an efficient representation. Learning and representing effective state-feedback controllers for non-linear stochastic control problems is a very challenging, and largely unsolved, problem. We show how to learn and represent such controllers using ideas from the cross entropy method. We derive a gradient descent method that allows to learn feed-back controllers using an arbitrary parametrisation. We refer to this method as the path integral cross entropy method or PICE. We illustrate this method for some simple examples. The PI control methods can be used to estimate the posterior distribution in latent state models. In neuroscience these problems arise when estimating connectivity from neural recording data using EM. We demonstrate the PI control method as an accurate alternative to particle filtering.

The design of multirate digital control systems

NASA Technical Reports Server (NTRS)

Berg, M. C.

1986-01-01

The successive loop closures synthesis method is the only method for multirate (MR) synthesis in common use. A new method for MR synthesis is introduced which requires a gradient-search solution to a constrained optimization problem. Some advantages of this method are that the control laws for all control loops are synthesized simultaneously, taking full advantage of all cross-coupling effects, and that simple, low-order compensator structures are easily accomodated. The algorithm and associated computer program for solving the constrained optimization problem are described. The successive loop closures , optimal control, and constrained optimization synthesis methods are applied to two example design problems. A series of compensator pairs are synthesized for each example problem. The succesive loop closure, optimal control, and constrained optimization synthesis methods are compared, in the context of the two design problems.

Reynolds number dependence of large-scale friction control in turbulent channel flow

NASA Astrophysics Data System (ADS)

Canton, Jacopo; Örlü, Ramis; Chin, Cheng; Schlatter, Philipp

2016-12-01

The present work investigates the effectiveness of the control strategy introduced by Schoppa and Hussain [Phys. Fluids 10, 1049 (1998), 10.1063/1.869789] as a function of Reynolds number (Re). The skin-friction drag reduction method proposed by these authors, consisting of streamwise-invariant, counter-rotating vortices, was analyzed by Canton et al. [Flow, Turbul. Combust. 97, 811 (2016), 10.1007/s10494-016-9723-8] in turbulent channel flows for friction Reynolds numbers (Reτ) corresponding to the value of the original study (i.e., 104) and 180. For these Re, a slightly modified version of the method proved to be successful and was capable of providing a drag reduction of up to 18%. The present study analyzes the Reynolds number dependence of this drag-reducing strategy by performing two sets of direct numerical simulations (DNS) for Reτ=360 and 550. A detailed analysis of the method as a function of the control parameters (amplitude and wavelength) and Re confirms, on the one hand, the effectiveness of the large-scale vortices at low Re and, on the other hand, the decreasing and finally vanishing effectiveness of this method for higher Re. In particular, no drag reduction can be achieved for Reτ=550 for any combination of the parameters controlling the vortices. For low Reynolds numbers, the large-scale vortices are able to affect the near-wall cycle and alter the wall-shear-stress distribution to cause an overall drag reduction effect, in accordance with most control strategies. For higher Re, instead, the present method fails to penetrate the near-wall region and cannot induce the spanwise velocity variation observed in other more established control strategies, which focus on the near-wall cycle. Despite the negative outcome, the present results demonstrate the shortcomings of the control strategy and show that future focus should be on methods that directly target the near-wall region or other suitable alternatives.

Survey of methods for secure connection to the internet

NASA Astrophysics Data System (ADS)

Matsui, Shouichi

1994-04-01

This paper describes a study of a security method of protecting inside network computers against outside miscreants and unwelcome visitors and a control method when these computers are connected with the Internet. In the present Internet, a method to encipher all data cannot be used, so that it is necessary to utilize PEM (Privacy Enhanced Mail) capable of the encipherment and conversion of secret information. For preventing miscreant access by eavesdropping password, one-time password is effective. The most cost-effective method is a firewall system. This system lies between the outside and inside network. By limiting computers that directly communicate with the Internet, control is centralized and inside network security is protected. If the security of firewall systems is strictly controlled under correct setting, security within the network can be secured even in open networks such as the Internet.

Intelligent automated control of life support systems using proportional representations.

PubMed

Wu, Annie S; Garibay, Ivan I

2004-06-01

Effective automatic control of Advanced Life Support Systems (ALSS) is a crucial component of space exploration. An ALSS is a coupled dynamical system which can be extremely sensitive and difficult to predict. As a result, such systems can be difficult to control using deliberative and deterministic methods. We investigate the performance of two machine learning algorithms, a genetic algorithm (GA) and a stochastic hill-climber (SH), on the problem of learning how to control an ALSS, and compare the impact of two different types of problem representations on the performance of both algorithms. We perform experiments on three ALSS optimization problems using five strategies with multiple variations of a proportional representation for a total of 120 experiments. Results indicate that although a proportional representation can effectively boost GA performance, it does not necessarily have the same effect on other algorithms such as SH. Results also support previous conclusions that multivector control strategies are an effective method for control of coupled dynamical systems.

Cost-Effectiveness Analysis of Three Leprosy Case Detection Methods in Northern Nigeria

PubMed Central

Ezenduka, Charles; Post, Erik; John, Steven; Suraj, Abdulkarim; Namadi, Abdulahi; Onwujekwe, Obinna

2012-01-01

Background Despite several leprosy control measures in Nigeria, child proportion and disability grade 2 cases remain high while new cases have not significantly reduced, suggesting continuous spread of the disease. Hence, there is the need to review detection methods to enhance identification of early cases for effective control and prevention of permanent disability. This study evaluated the cost-effectiveness of three leprosy case detection methods in Northern Nigeria to identify the most cost-effective approach for detection of leprosy. Methods A cross-sectional study was carried out to evaluate the additional benefits of using several case detection methods in addition to routine practice in two north-eastern states of Nigeria. Primary and secondary data were collected from routine practice records and the Nigerian Tuberculosis and Leprosy Control Programme of 2009. The methods evaluated were Rapid Village Survey (RVS), Household Contact Examination (HCE) and Traditional Healers incentive method (TH). Effectiveness was measured as number of new leprosy cases detected and cost-effectiveness was expressed as cost per case detected. Costs were measured from both providers' and patients' perspectives. Additional costs and effects of each method were estimated by comparing each method against routine practise and expressed as incremental cost-effectiveness ratio (ICER). All costs were converted to the U.S. dollar at the 2010 exchange rate. Univariate sensitivity analysis was used to evaluate uncertainties around the ICER. Results The ICER for HCE was $142 per additional case detected at all contact levels and it was the most cost-effective method. At ICER of $194 per additional case detected, THs method detected more cases at a lower cost than the RVS, which was not cost-effective at $313 per additional case detected. Sensitivity analysis showed that varying the proportion of shared costs and subsistent wage for valuing unpaid time did not significantly change the results. Conclusion Complementing routine practice with household contact examination is the most cost-effective approach to identify new leprosy cases and we recommend that, depending on acceptability and feasibility, this intervention is introduced for improved case detection in Northern Nigeria. PMID:23029580

Flux control coefficients determined by inhibitor titration: the design and analysis of experiments to minimize errors.

PubMed Central

Small, J R

1993-01-01

This paper is a study into the effects of experimental error on the estimated values of flux control coefficients obtained using specific inhibitors. Two possible techniques for analysing the experimental data are compared: a simple extrapolation method (the so-called graph method) and a non-linear function fitting method. For these techniques, the sources of systematic errors are identified and the effects of systematic and random errors are quantified, using both statistical analysis and numerical computation. It is shown that the graph method is very sensitive to random errors and, under all conditions studied, that the fitting method, even under conditions where the assumptions underlying the fitted function do not hold, outperformed the graph method. Possible ways of designing experiments to minimize the effects of experimental errors are analysed and discussed. PMID:8257434

Inter-Vehicle Communication System Utilizing Autonomous Distributed Transmit Power Control

NASA Astrophysics Data System (ADS)

Hamada, Yuji; Sawa, Yoshitsugu; Goto, Yukio; Kumazawa, Hiroyuki

In ad-hoc network such as inter-vehicle communication (IVC) system, safety applications that vehicles broadcast the information such as car velocity, position and so on periodically are considered. In these applications, if there are many vehicles broadcast data in a communication area, congestion incurs a problem decreasing communication reliability. We propose autonomous distributed transmit power control method to keep high communication reliability. In this method, each vehicle controls its transmit power using feed back control. Furthermore, we design a communication protocol to realize the proposed method, and we evaluate the effectiveness of proposed method using computer simulation.

A modified Finite Element-Transfer Matrix for control design of space structures

NASA Technical Reports Server (NTRS)

Tan, T.-M.; Yousuff, A.; Bahar, L. Y.; Konstandinidis, M.

1990-01-01

The Finite Element-Transfer Matrix (FETM) method was developed for reducing the computational efforts involved in structural analysis. While being widely used by structural analysts, this method does, however, have certain limitations, particularly when used for the control design of large flexible structures. In this paper, a new formulation based on the FETM method is presented. The new method effectively overcomes the limitations in the original FETM method, and also allows an easy construction of reduced models that are tailored for the control design. Other advantages of this new method include the ability to extract open loop frequencies and mode shapes with less computation, and simplification of the design procedures for output feedback, constrained compensation, and decentralized control. The development of this new method and the procedures for generating reduced models using this method are described in detail and the role of the reduced models in control design is discussed through an illustrative example.

Control and synchronisation of a novel seven-dimensional hyperchaotic system with active control

NASA Astrophysics Data System (ADS)

Varan, Metin; Akgul, Akif

2018-04-01

In this work, active control method is proposed for controlling and synchronising seven-dimensional (7D) hyperchaotic systems. The seven-dimensional hyperchaotic system is considered for the implementation. Seven-dimensional hyperchaotic system is also investigated via time series, phase portraits and bifurcation diagrams. For understanding the impact of active controllers on global asymptotic stability of synchronisation and control errors, the Lyapunov function is used. Numerical analysis is done to reveal the effectiveness of applied active control method and the results are discussed.

The effects of insect biological control on a Tamarix invaded ecosystem: ecosystem water and carbon fluxes and plant-level responses

USDA-ARS?s Scientific Manuscript database

Background / Questions / Methods: Tamarix spp. (saltcedar) has invaded many river systems in the western United States with detrimental impacts to flora and fauna. Traditional methods of invasive plant control have been ineffective or costly. Therefore, insect biological control of Tamarix with Di...

[Effect on tranquilizing and allaying excitement needling method on brain blood flow in the patients of insomnia of heart and spleen deficiency].

PubMed

Yan, Xing-ke; Zhang, Yan; Yu, Lu; Yue, Gong-lei; Li, Tie; Chen, Cheng; Cui, Hai-fu; Wang, Fu-chun

2010-02-01

To observe the therapeutic effect of tranquilizing and allaying excitement needling method on insomnia of heart and spleen deficiency and the effect of brain blood flow. Sixty cases were randomly divided into a tranquilizing and allaying excitement needling method group (observation group) and an eight confluence points selected group (control group), 30 cases in each group. The observation group was treated by acupuncture at Sishencong (EX-HN 1), Shenmen (HT 7), and Sanyinjiao (SP 6) with tranquilizing and allaying excitement needling method. The control group was treated by acupuncture at Shenmai (BL 62) and Zhaohai (KI 6). Their therapeutic effects and changes of brain blood flow were observed. The total effective rate was 93.3% (28/30) in the observation group which was better than 83.3% (25/30) in the control group (P < 0.05). After treatment, the peak velocity of systolic (Vp) and diastolic blood flow velocity (Vd) of middle cerebral artery, basilar artery and vertebral artery were increased in the both groups (P < 0.01, P < 0.05), with more obvious increase in the observation group (P < 0.01, P < 0.05), except the Vd of left vertebral artery. Both the tranquilizing and allaying excitement needling method and the eight confluence points selected needling method can improve the clinical signs and symptoms. Meanwhile, the therapeutic effect of acupuncture is related with improvement of brain blood flow. However, the tranquilizing and allaying excitement needling method has better therapeutic effect on insomnia of heart and spleen deficiency.

Ranking filter methods for concentrating pathogens in lake water

USDA-ARS?s Scientific Manuscript database

Accurately comparing filtration methods for concentrating waterborne pathogens is difficult because of two important water matrix effects on recovery measurements, the effect on PCR quantification and the effect on filter performance. Regarding the first effect, we show how to create a control water...

Flow Separation Control Over a Ramp Using Sweeping Jet Actuators

NASA Technical Reports Server (NTRS)

Koklu, Mehti; Owens, Lewis R.

2014-01-01

Flow separation control on an adverse-pressure-gradient ramp model was investigated using various flow-control methods in the NASA Langley 15-Inch Wind Tunnel. The primary flow-control method studied used a sweeping jet actuator system to compare with more classic flow-control techniques such as micro-vortex generators, steady blowing, and steady- and unsteady-vortex generating jets. Surface pressure measurements and a new oilflow visualization technique were used to characterize the effects of these flow-control actuators. The sweeping jet actuators were run in three different modes to produce steady-straight, steady-angled, and unsteady-oscillating jets. It was observed that all of these flow-control methods are effective in controlling the separated flows on the ramp model. The steady-straight jet energizes the boundary layer by momentum addition and was found to be the least effective method for a fixed momentum coefficient. The steady-angled jets achieved better performance than the steady-straight jets because they generate streamwise vortices that energize the boundary layer by mixing high-momentum fluid with near wall low-momentum fluid. The unsteady-oscillating jets achieved the best performance by increasing the pressure recovery and reducing the downstream flow separation. Surface flow visualizations indicated that two out-of-phase counter-rotating vortices are generated per sweeping jet actuator, while one vortex is generated per vortex-generating jets. The extra vortex resulted in increased coverage, more pressure recovery, and reduced flow separation.

Intermittent control of coexisting attractors.

PubMed

Liu, Yang; Wiercigroch, Marian; Ing, James; Pavlovskaia, Ekaterina

2013-06-28

This paper proposes a new control method applicable for a class of non-autonomous dynamical systems that naturally exhibit coexisting attractors. The central idea is based on knowledge of a system's basins of attraction, with control actions being applied intermittently in the time domain when the actual trajectory satisfies a proximity constraint with regards to the desired trajectory. This intermittent control uses an impulsive force to perturb one of the system attractors in order to switch the system response onto another attractor. This is carried out by bringing the perturbed state into the desired basin of attraction. The method has been applied to control both smooth and non-smooth systems, with the Duffing and impact oscillators used as examples. The strength of the intermittent control force is also considered, and a constrained intermittent control law is introduced to investigate the effect of limited control force on the efficiency of the controller. It is shown that increasing the duration of the control action and/or the number of control actuations allows one to successfully switch between the stable attractors using a lower control force. Numerical and experimental results are presented to demonstrate the effectiveness of the proposed method.

Estimating Causal Effects from Family Planning Health Communication Campaigns Using Panel Data: The “Your Health, Your Wealth” Campaign in Egypt

PubMed Central

Hutchinson, Paul L.; Meekers, Dominique

2012-01-01

Background Health communication campaigns – involving mass media and interpersonal communication - have long been utilized by national family planning programs to create awareness about contraceptive methods, to shift social norms related to fertility control, and to promote specific behaviors, such as the use of condoms, injectable methods or permanent sterilization. However, demonstrating the effectiveness of these campaigns is often complicated because the infeasibility of experimental designs generally yields statistically non-equivalent samples of campaign-exposed and unexposed individuals. Methods Using data from a panel survey of reproductive age women in Egypt, we estimate the effects of the multimedia health communication campaign “Your Health, Your Wealth” (“Sahatek Sarwetek”) on precursors to contraceptive use (e.g., spousal communication, birth spacing attitudes) and on modern contraceptive use. Difference-in-differences and fixed effects estimators that exploit the panel nature of the data are employed to control for both observed and unobserved heterogeneity in the sample of women who self-report recall of the messages, thereby potentially improving upon methods that make no such controls or that rely solely on cross-sectional data. Findings All of the estimators find positive effects of the “Your Health, Your Wealth” campaign on reproductive health outcomes, though the magnitudes of those effects diverge, often considerably. Difference-in-differences estimators find that exposure to the campaign increases the likelihood of spousal discussions by 14.4 percentage points (pp.) (SE = .039, p<0.001) but has no effect on contraceptive use. In contrast, the fixed effects, instrumental variables estimator, controlling for unobserved heterogeneity, finds a large, statistically significant effect on modern contraceptive use (27.4 pp., SE = 0.135, p = 0.043). Conclusions The difficulties of evaluating family planning communication programs may be surmountable using panel data and analytic methods that address both observed and unobserved heterogeneity in exposure. Not controlling for such effects may lead to substantial underestimates of the effectiveness of such campaigns. PMID:23049961

The Effect of Vocal Training Methods on Improving Turkish Accent Defects

ERIC Educational Resources Information Center

Aycan, Kivanc; Evren, Gul Fahriye

2016-01-01

Problem Statement: Despite analyses of how vocal training methods can correct or improve Turkish-language accent defects, for most voice educators, the most important methods continue to be breathe management control and correct vocalization exercises. We therefore sought to demonstrate the relationship of song lyrics to breathe control, accent…

Effects of a Format-based Second Language Teaching Method in Kindergarten.

ERIC Educational Resources Information Center

Uilenburg, Noelle; Plooij, Frans X.; de Glopper, Kees; Damhuis, Resi

2001-01-01

Focuses on second language teaching with a format-based method. The differences between a format-based teaching method and a standard approach used as treatments in a quasi-experimental, non-equivalent control group are described in detail. Examines whether the effects of a format-based teaching method and a standard foreign language method differ…

PID Tuning Using Extremum Seeking

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

Killingsworth, N; Krstic, M

2005-11-15

Although proportional-integral-derivative (PID) controllers are widely used in the process industry, their effectiveness is often limited due to poor tuning. Manual tuning of PID controllers, which requires optimization of three parameters, is a time-consuming task. To remedy this difficulty, much effort has been invested in developing systematic tuning methods. Many of these methods rely on knowledge of the plant model or require special experiments to identify a suitable plant model. Reviews of these methods are given in [1] and the survey paper [2]. However, in many situations a plant model is not known, and it is not desirable to openmore » the process loop for system identification. Thus a method for tuning PID parameters within a closed-loop setting is advantageous. In relay feedback tuning [3]-[5], the feedback controller is temporarily replaced by a relay. Relay feedback causes most systems to oscillate, thus determining one point on the Nyquist diagram. Based on the location of this point, PID parameters can be chosen to give the closed-loop system a desired phase and gain margin. An alternative tuning method, which does not require either a modification of the system or a system model, is unfalsified control [6], [7]. This method uses input-output data to determine whether a set of PID parameters meets performance specifications. An adaptive algorithm is used to update the PID controller based on whether or not the controller falsifies a given criterion. The method requires a finite set of candidate PID controllers that must be initially specified [6]. Unfalsified control for an infinite set of PID controllers has been developed in [7]; this approach requires a carefully chosen input signal [8]. Yet another model-free PID tuning method that does not require opening of the loop is iterative feedback tuning (IFT). IFT iteratively optimizes the controller parameters with respect to a cost function derived from the output signal of the closed-loop system, see [9]. This method is based on the performance of the closed-loop system during a step response experiment [10], [11]. In this article we present a method for optimizing the step response of a closed-loop system consisting of a PID controller and an unknown plant with a discrete version of extremum seeking (ES). Specifically, ES is used to minimize a cost function similar to that used in [10], [11], which quantifies the performance of the PID controller. ES, a non-model-based method, iteratively modifies the arguments (in this application the PID parameters) of a cost function so that the output of the cost function reaches a local minimum or local maximum. In the next section we apply ES to PID controller tuning. We illustrate this technique through simulations comparing the effectiveness of ES to other PID tuning methods. Next, we address the importance of the choice of cost function and consider the effect of controller saturation. Furthermore, we discuss the choice of ES tuning parameters. Finally, we offer some conclusions.« less

A multi-refuge study to evaluate the effectiveness of growing-season and dormant-season burns to control cattail

USGS Publications Warehouse

Gleason, Robert A.; Tangen, Brian A.; Laubhan, Murray K.; Lor, Socheata

2012-01-01

Proliferation of invasive cattails (for example, Typha x glauca, T. angustifolia) is a concern of wetland managers across the country, and numerous methods have been used to control the spatial extent and density of the plant. To date, however, no single method has proven widely or consistently effective at reducing the long-term growth and spread of these species. We performed a multi-refuge study to evaluate the relative effects of growing-season and dormant-season prescribed burns on cattail production and to gain insight on variables such as soil moisture, groundwater, and biomass that affect the efficacy of burning as a control method. Results indicate total cattail cover recovers to pre-burn levels within 1 year regardless of whether the controlled burn was implemented during the growing season or dormant season. Growing-season burns, however, did result in lower aboveground and belowground cattail biomass 1-year post-burn, whereas no significant change in biomass was detected for dormant-season burns. Study results support the premise that burns implemented during the growing season should have a greater effect on nutrient reserves and cattail re-growth. Results from this and other studies suggest long-term research that incorporates multiple management strategies will be required to evaluate the potential of prescribed burning as a method to control cattail.

Exact controllability for a Thermodiffusion System with locally distributed controls

NASA Astrophysics Data System (ADS)

de Moraes, F. G.; Schulz, R. A.; Soriano, J. A.

2018-03-01

In this work we establish a exact controllability result for a thermodiffusion system, modeled by Cattaneo's law, posed in a one-dimensional domain. In the present model the control mechanisms are effective in a small subinterval of the domain. To obtain the desired results, we prove an observability inequality for the adjoint system which, together with the multiplier methods and the Hilbert Uniqueness Method (HUM) developed by J.L. Lions, gives the controllability.

Influence of air-jet vortex generator diameter on separation region

NASA Astrophysics Data System (ADS)

Szwaba, Ryszard

2013-08-01

Control of shock wave and boundary layer interaction continues to attract a lot of attention. In recent decades several methods of interaction control have been investigated. The research has mostly concerned solid (vane type) vortex generators and transpiration methods of suction and blowing. This investigation concerns interaction control using air-jets to generate streamwise vortices. The effectiveness of air-jet vortex generators in controlling separation has been proved in a previous research. The present paper focuses on the influence of the vortex generator diameter on the separation region. It presents the results of experimental investigations and provides new guidelines for the design of air-jet vortex generators to obtain more effective separation control.

Effects of breast and colorectal cancer on labour market outcomes-average effects and educational gradients.

PubMed

Heinesen, Eskil; Kolodziejczyk, Christophe

2013-12-01

We estimate causal effects of breast and colorectal cancer on labour market outcomes 1-3 years after the diagnosis. Based on Danish administrative data we estimate average treatment effects on the treated by propensity score weighting methods using persons with no cancer diagnosis as control group. We conduct robustness checks using matching, difference-in-differences methods and an alternative control group of later cancer patients. The different methods give approximately the same results. Cancer increases the risks of leaving the labour force and receiving disability pension, and the effects are larger for the less educated. Effects on income are small and mostly insignificant. We investigate some of the mechanisms which may be important in explaining the educational gradient in effects of cancer on labour market attachment. Copyright © 2013 Elsevier B.V. All rights reserved.

Chaos, Chaos Control and Synchronization of a Gyrostat System

NASA Astrophysics Data System (ADS)

GE, Z.-M.; LIN, T.-N.

2002-03-01

The dynamic behavior of a gyrostat system subjected to external disturbance is studied in this paper. By applying numerical results, phase diagrams, power spectrum, period-T maps, and Lyapunov exponents are presented to observe periodic and choatic motions. The effect of the parameters changed in the system can be found in the bifurcation and parametric diagrams. For global analysis, the basins of attraction of each attractor of the system are located by employing the modified interpolated cell mapping (MICM) method. Several methods, the delayed feedback control, the addition of constant torque, the addition of periodic force, the addition of periodic impulse torque, injection of dither signal control, adaptive control algorithm (ACA) control and bang-bang control are used to control chaos effectively. Finally, synchronization of chaos in the gyrostat system is studied.

When is category specific in Alzheimer's disease?

PubMed

Laws, Keith R; Gale, Tim M; Leeson, Verity C; Crawford, John R

2005-08-01

Mixed findings have emerged concerning whether category-specific disorders occur in Alzheimer's disease. Factors that may contribute to these inconsistencies include: ceiling effects/skewed distributions for control data in some studies; differences in the severity of cognitive deficit in patients; and differences in the type of analysis (in particular, if and how controls are used to analyse single case data). We examined picture naming in Alzheimer's patients and matched elderly healthy normal controls in three experiments. These experiments used stimuli that did and did not produce ceiling effects/skewed data in controls. In Experiment 1, we examined for category effects in individual DAT patients using commonly used analyses for single cases (chi2 and z-scores). The different techniques produced quite different outcomes. In Experiment 2a, we used the same techniques on a different group of patients with similar outcomes. Finally, in Experiment 2b, we examined the same patients but (a) used stimuli that did not produce ceiling effects/skewed distributions in healthy controls, and (b) used statistical methods that did not treat the control sample as a population. We found that ceiling effects in controls may markedly inflate the incidence of dissociations in which living things are differentially impaired and seriously underestimate dissociations in the opposite direction. In addition, methods that treat the control sample as a population led to inflation in the overall number of dissociations detected. These findings have implications for the reliability of category effects previously reported both in Alzheimer patients and in other pathologies. In particular, they suggest that the greater proportion of living than nonliving deficits reported in the literature may be an artifact of the methods used.

Division by zero, pseudo-division by zero, Zhang dynamics method and Zhang-gradient method about control singularity conquering

NASA Astrophysics Data System (ADS)

Zhang, Yunong; Zhang, Yinyan; Chen, Dechao; Xiao, Zhengli; Yan, Xiaogang

2017-01-01

In this paper, the division-by-zero (DBO) problem in the field of nonlinear control, which is traditionally termed the control singularity problem (or specifically, controller singularity problem), is investigated by the Zhang dynamics (ZD) method and the Zhang-gradient (ZG) method. According to the impact of the DBO problem on the state variables of the controlled nonlinear system, the concepts of the pseudo-DBO problem and the true-DBO problem are proposed in this paper, which provide a new perspective for the researchers on the DBO problems as well as nonlinear control systems. Besides, the two classes of DBO problems are solved under the framework of the ZG method. Specific examples are shown and investigated in this paper to illustrate the two proposed concepts and the efficacy of the ZG method in conquering pseudo-DBO and true-DBO problems. The application of the ZG method to the tracking control of a two-wheeled mobile robot further substantiates the effectiveness of the ZG method. In addition, the ZG method is successfully applied to the tracking control of a pure-feedback nonlinear system.

Control Law for Automatic Landing Using Fuzzy-Logic Control

NASA Astrophysics Data System (ADS)

Kato, Akio; Inagaki, Yoshiki

The effectiveness of a fuzzy-logic control law for automatically landing an aircraft that handles both the control to lead an aircraft from horizontal flight at an altitude of 500 meters to flight along the glide-path course near the runway, as well as the control to direct the aircraft to land smoothly on a runway, was investigated. The control law for the automatic landing was designed to match the design goals of directing an aircraft from horizontal flight to flight along a glide-path course quickly and smoothly, and for landing smoothly on a runway. The design of the control law and evaluation of the control performance were performed considering the ground effect at landing. As a result, it was confirmed that the design goals were achieved. Even if the characteristics of the aircraft change greatly, the proposed control law is able to maintain the control performance. Moreover, it was confirmed to be able to land an aircraft safely during air turbulence. The present paper indicates that fuzzy-logic control is an effective and flexible method when applied to the control law for automatic landing, and the design method of the control law using fuzzy-logic control was obtained.

Approximation methods for control of acoustic/structure models with piezoceramic actuators

NASA Technical Reports Server (NTRS)

Banks, H. T.; Fang, W.; Silcox, R. J.; Smith, R. C.

1991-01-01

The active control of acoustic pressure in a 2-D cavity with a flexible boundary (a beam) is considered. Specifically, this control is implemented via piezoceramic patches on the beam which produces pure bending moments. The incorporation of the feedback control in this manner leads to a system with an unbounded input term. Approximation methods in this manner leads to a system with an unbounded input term. Approximation methods in the context of linear quadratic regulator (LQR) state space control formulation are discussed and numerical results demonstrating the effectiveness of this approach in computing feedback controls for noise reduction are presented.

Optimized method for manufacturing large aspheric surfaces

NASA Astrophysics Data System (ADS)

Zhou, Xusheng; Li, Shengyi; Dai, Yifan; Xie, Xuhui

2007-12-01

Aspheric optics are being used more and more widely in modern optical systems, due to their ability of correcting aberrations, enhancing image quality, enlarging the field of view and extending the range of effect, while reducing the weight and volume of the system. With optical technology development, we have more pressing requirement to large-aperture and high-precision aspheric surfaces. The original computer controlled optical surfacing (CCOS) technique cannot meet the challenge of precision and machining efficiency. This problem has been thought highly of by researchers. Aiming at the problem of original polishing process, an optimized method for manufacturing large aspheric surfaces is put forward. Subsurface damage (SSD), full aperture errors and full band of frequency errors are all in control of this method. Lesser SSD depth can be gained by using little hardness tool and small abrasive grains in grinding process. For full aperture errors control, edge effects can be controlled by using smaller tools and amendment model with material removal function. For full band of frequency errors control, low frequency errors can be corrected with the optimized material removal function, while medium-high frequency errors by using uniform removing principle. With this optimized method, the accuracy of a K9 glass paraboloid mirror can reach rms 0.055 waves (where a wave is 0.6328μm) in a short time. The results show that the optimized method can guide large aspheric surface manufacturing effectively.

Analog self-powered harvester achieving switching pause control to increase harvested energy

NASA Astrophysics Data System (ADS)

Makihara, Kanjuro; Asahina, Kei

2017-05-01

In this paper, we propose a self-powered analog controller circuit to increase the efficiency of electrical energy harvesting from vibrational energy using piezoelectric materials. Although the existing synchronized switch harvesting on inductor (SSHI) method is designed to produce efficient harvesting, its switching operation generates a vibration-suppression effect that reduces the harvested levels of electrical energy. To solve this problem, the authors proposed—in a previous paper—a switching method that takes this vibration-suppression effect into account. This method temporarily pauses the switching operation, allowing the recovery of the mechanical displacement and, therefore, of the piezoelectric voltage. In this paper, we propose a self-powered analog circuit to implement this switching control method. Self-powered vibration harvesting is achieved in this study by attaching a newly designed circuit to an existing analog controller for SSHI. This circuit aims to effectively implement the aforementioned new switching control strategy, where switching is paused in some vibration peaks, in order to allow motion recovery and a consequent increase in the harvested energy. Harvesting experiments performed using the proposed circuit reveal that the proposed method can increase the energy stored in the storage capacitor by a factor of 8.5 relative to the conventional SSHI circuit. This proposed technique is useful to increase the harvested energy especially for piezoelectric systems having large coupling factor.

An EMG-Based Control for an Upper-Limb Power-Assist Exoskeleton Robot.

PubMed

Kiguchi, K; Hayashi, Y

2012-08-01

Many kinds of power-assist robots have been developed in order to assist self-rehabilitation and/or daily life motions of physically weak persons. Several kinds of control methods have been proposed to control the power-assist robots according to user's motion intention. In this paper, an electromyogram (EMG)-based impedance control method for an upper-limb power-assist exoskeleton robot is proposed to control the robot in accordance with the user's motion intention. The proposed method is simple, easy to design, humanlike, and adaptable to any user. A neurofuzzy matrix modifier is applied to make the controller adaptable to any users. Not only the characteristics of EMG signals but also the characteristics of human body are taken into account in the proposed method. The effectiveness of the proposed method was evaluated by the experiments.

Pressure-Aware Control Layer Optimization for Flow-Based Microfluidic Biochips.

PubMed

Wang, Qin; Xu, Yue; Zuo, Shiliang; Yao, Hailong; Ho, Tsung-Yi; Li, Bing; Schlichtmann, Ulf; Cai, Yici

2017-12-01

Flow-based microfluidic biochips are attracting increasing attention with successful biomedical applications. One critical issue with flow-based microfluidic biochips is the large number of microvalves that require peripheral control pins. Even using the broadcasting addressing scheme, i.e., one control pin controls multiple microvalves simultaneously, thousands of microvalves would still require hundreds of control prins, which is unrealistic. To address this critical challenge in control scalability, the control-layer multiplexer is introduced to effectively reduce the number of control pins into log scale of the number of microvalves. There are two practical design issues with the control-layer multiplexer: (1) the reliability issue caused by the frequent control-valve switching, and (2) the pressure degradation problem caused by the control-valve switching without pressure refreshing from the pressure source. This paper addresses these two design issues by the proposed Hamming-distance-based switching sequence optimization method and the XOR-based pressure refreshing method. Simulation results demonstrate the effectiveness and efficiency of the proposed methods with an average 77.2% (maximum 89.6%) improvement in total pressure refreshing cost, and an average 88.5% (maximum 90.0%) improvement in pressure deviation.

Planting pattern and weed control method influence on yield production of corn (Zea mays L.)

NASA Astrophysics Data System (ADS)

Purba, E.; Nasution, D. P.

2018-02-01

Field experiment was carried out to evaluate the influence of planting patterns and weed control methods on the growth and yield of corn. The effect of the planting pattern and weed control method was studied in a split plot design. The main plots were that of planting pattern single row (25cm x 60cm), double row (25cm x 25cm x 60cm) and triangle row ( 25cm x 25cm x 25cm). Subplot was that of weed control method consisted five methods namely weed free throughout the growing season, hand weeding, sprayed with glyphosate, sprayed with paraquat, and no weeding.. Result showed that both planting pattern and weed control method did not affect the growth of corn. However, planting pattern and weed control method significantly affected yield production. Yield resulted from double row and triangle planting pattern was 14% and 41% higher, consecutively, than that of single row pattern. The triangle planting pattern combined with any weed control method produced the highest yield production of corn.

Broadcast application of scythe for broadleaf weed control in spring-transplanted onions

USDA-ARS?s Scientific Manuscript database

Producers using organic methods for onion production need organic herbicides that will effectively provide post-emergent weed control. In 2008, a second year of field research was conducted to determine the effect of broadcast over-the-top application of Scythe (57% pelargonic acid) on weed control...

Compared to What? The Effectiveness of Synthetic Control Methods for Causal Inference in Educational Assessment

ERIC Educational Resources Information Center

Johnson, Clay Stephen

2013-01-01

Synthetic control methods are an innovative matching technique first introduced within the economics and political science literature that have begun to find application in educational research as well. Synthetic controls create an aggregate-level, time-series comparison for a single treated unit of interest for causal inference with observational…

[Investigation on production process quality control of traditional Chinese medicine--Banlangen granule as an example].

PubMed

Tan, Manrong; Yan, Dan; Qiu, Lingling; Chen, Longhu; Yan, Yan; Jin, Cheng; Li, Hanbing; Xiao, Xiaohe

2012-04-01

For the quality management system of herbal medicines, intermediate and finished products it exists the " short board" effect of methodologies. Based on the concept of process control, new strategies and new methods of the production process quality control had been established with the consideration of the actual production of traditional Chinese medicine an the characteristics of Chinese medicine. Taking Banlangen granule as a practice example, which was effective and widespread application, character identification, determination of index components, chemical fingerprint and biometrics technology were sequentially used respectively to assess the quality of Banlangen herbal medicines, intermediate (water extraction and alcohol precipitation) and finished product. With the transfer rate of chemical information and biological potency as indicators, the effectiveness and transmission of the above different assessments and control methods had been researched. And ultimately, the process quality control methods of Banlangen granule, which were based on chemical composition analysis-biometric analysis, had been set up. It can not only validly solute the current status that there were many manufacturers varying quality of Banlangen granule, but also ensure and enhance its clinical efficacy. Furthermore it provided a foundation for the construction of the quality control of traditional Chinese medicine production process.

Views of Cameroonian sex workers on a woman-controlled method of contraception and disease protection.

PubMed

Visness, C M; Ulin, P; Pfannenschmidt, S; Zekeng, L

1998-11-01

Five hundred and twenty female Cameroonian sex workers participating in a clinical trial of the effectiveness of nonoxynol-9 (N-9) contraceptive film to prevent HIV infection were interviewed to determine their experience with this woman-controlled method. The sex workers liked the film, with over 80% stating they would continue to use it if it were shown to be effective against HIV and were to become widely available. However, they were much more likely to use condoms and films simultaneously with their clients (40%) than with their regular partners (16%). The advantages ascribed to the film were that its use was under the woman's control; it could be used without the partner's knowledge; it allowed direct contact between partners; and it provided back-up protection in case of condom breakage. Data from this small study suggest that development of an effective, woman-controlled method of pregnancy and disease protection would be welcomed by these women.

Malaria vector control: from past to future.

PubMed

Raghavendra, Kamaraju; Barik, Tapan K; Reddy, B P Niranjan; Sharma, Poonam; Dash, Aditya P

2011-04-01

Malaria is one of the most common vector-borne diseases widespread in the tropical and subtropical regions. Despite considerable success of malaria control programs in the past, malaria still continues as a major public health problem in several countries. Vector control is an essential part for reducing malaria transmission and became less effective in recent years, due to many technical and administrative reasons, including poor or no adoption of alternative tools. Of the different strategies available for vector control, the most successful are indoor residual spraying and insecticide-treated nets (ITNs), including long-lasting ITNs and materials. Earlier DDT spray has shown spectacular success in decimating disease vectors but resulted in development of insecticide resistance, and to control the resistant mosquitoes, organophosphates, carbamates, and synthetic pyrethroids were introduced in indoor residual spraying with needed success but subsequently resulted in the development of widespread multiple insecticide resistance in vectors. Vector control in many countries still use insecticides in the absence of viable alternatives. Few developments for vector control, using ovitraps, space spray, biological control agents, etc., were encouraging when used in limited scale. Likewise, recent introduction of safer vector control agents, such as insect growth regulators, biocontrol agents, and natural plant products have yet to gain the needed scale of utility for vector control. Bacterial pesticides are promising and are effective in many countries. Environmental management has shown sufficient promise for vector control and disease management but still needs advocacy for inter-sectoral coordination and sometimes are very work-intensive. The more recent genetic manipulation and sterile insect techniques are under development and consideration for use in routine vector control and for these, standardized procedures and methods are available but need thorough understanding of biology, ethical considerations, and sufficiently trained manpower for implementation being technically intensive methods. All the methods mentioned in the review that are being implemented or proposed for implementation needs effective inter-sectoral coordination and community participation. The latest strategy is evolution-proof insecticides that include fungal biopesticides, Wolbachia, and Denso virus that essentially manipulate the life cycle of the mosquitoes were found effective but needs more research. However, for effective vector control, integrated vector management methods, involving use of combination of effective tools, is needed and is also suggested by Global Malaria Control Strategy. This review article raises issues associated with the present-day vector control strategies and state opportunities with a focus on ongoing research and recent advances to enable to sustain the gains achieved so far.

EDUCORE project: a clinical trial, randomised by clusters, to assess the effect of a visual learning method on blood pressure control in the primary healthcare setting

PubMed Central

2010-01-01

Background High blood pressure (HBP) is a major risk factor for cardiovascular disease (CVD). European hypertension and cardiology societies as well as expert committees on CVD prevention recommend stratifying cardiovascular risk using the SCORE method, the modification of lifestyles to prevent CVD, and achieving good control over risk factors. The EDUCORE (Education and Coronary Risk Evaluation) project aims to determine whether the use of a cardiovascular risk visual learning method - the EDUCORE method - is more effective than normal clinical practice in improving the control of blood pressure within one year in patients with poorly controlled hypertension but no background of CVD; Methods/Design This work describes a protocol for a clinical trial, randomised by clusters and involving 22 primary healthcare clinics, to test the effectiveness of the EDUCORE method. The number of patients required was 736, all between 40 and 65 years of age (n = 368 in the EDUCORE and control groups), all of whom had been diagnosed with HBP at least one year ago, and all of whom had poorly controlled hypertension (systolic blood pressure ≥ 140 mmHg and/or diastolic ≥ 90 mmHg). All personnel taking part were explained the trial and trained in its methodology. The EDUCORE method contemplates the visualisation of low risk SCORE scores using images embodying different stages of a high risk action, plus the receipt of a pamphlet explaining how to better maintain cardiac health. The main outcome variable was the control of blood pressure; secondary outcome variables included the SCORE score, therapeutic compliance, quality of life, and total cholesterol level. All outcome variables were measured at the beginning of the experimental period and again at 6 and 12 months. Information on sex, age, educational level, physical activity, body mass index, consumption of medications, change of treatment and blood analysis results was also recorded; Discussion The EDUCORE method could provide a simple, inexpensive means of improving blood pressure control, and perhaps other health problems, in the primary healthcare setting; Trial registration The trial was registered with ClinicalTrials.gov, number NCT01155973 [http://ClinicalTrials.gov]. PMID:20673325

Methods to Control EMI Noises Produced in Power Converter Systems

NASA Astrophysics Data System (ADS)

Mutoh, Nobuyoshi; Ogata, Mitukatu

A new method to control EMI noises produced in power converters (rectifier and inverter) composed of IPMs (Intelligent Power Modules) is studied especially focusing on differential mode noises. The differential mode noises are occurred due to switching operations of the PWM control. As they are diffused into the ground through stray capacitors distributed between the ground and the power transmission lines and machine frames, differential mode noises should be confined and suppressed within the smallest area where power converters are laid out. It is impossible to control differential mode noises easily occurring diffusion by the conventional methods like filtering techniques. So, a new EMI noise control method using a multi-power circuit technique is proposed. The proposed method of the effectiveness has been verified through simulations and experiments.

The effectiveness of faecal removal methods of pasture management to control the cyathostomin burden of donkeys.

PubMed

Corbett, Christopher J; Love, Sandy; Moore, Anna; Burden, Faith A; Matthews, Jacqui B; Denwood, Matthew J

2014-01-24

The level of anthelmintic resistance within some cyathostomin parasite populations has increased to the level where sole reliance on anthelmintic-based control protocols is not possible. Management-based nematode control methods, including removal of faeces from pasture, are widely recommended for use in association with a reduction in anthelmintic use to reduce selection pressure for drug resistance; however, very little work has been performed to quantitatively assess the effectiveness of such methods. We analysed data obtained from 345 donkeys at The Donkey Sanctuary (Devon, UK), managed under three different pasture management techniques, to investigate the effectiveness of faeces removal in strongyle control in equids. The management groups were as follows: no removal of faeces from pasture, manual, twice-weekly removal of faeces from pasture and automatic, twice-weekly removal of faeces from pasture (using a mechanical pasture sweeper). From turn-out onto pasture in May, monthly faecal egg counts were obtained for each donkey and the dataset subjected to an auto regressive moving average model. There was little to no difference in faecal egg counts between the two methods of faecal removal; both resulted in significantly improved cyathostomin control compared to the results obtained from the donkeys that grazed pasture from which there was no faecal removal. This study represents a valuable and unique assessment of the effectiveness of the removal of equine faeces from pasture, and provides an evidence base from which to advocate twice-weekly removal of faeces from pasture as an adjunct for equid nematode control. Widespread adoption of this practice could substantially reduce anthelmintic usage, and hence reduce selection pressure for nematode resistance to the currently effective anthelmintic products.

Effective Desynchronization by Nonlinear Delayed Feedback

NASA Astrophysics Data System (ADS)

Popovych, Oleksandr V.; Hauptmann, Christian; Tass, Peter A.

2005-04-01

We show that nonlinear delayed feedback opens up novel means for the control of synchronization. In particular, we propose a demand-controlled method for powerful desynchronization, which does not require any time-consuming calibration. Our technique distinguishes itself by its robustness against variations of system parameters, even in strongly coupled ensembles of oscillators. We suggest our method for mild and effective deep brain stimulation in neurological diseases characterized by pathological cerebral synchronization.

Prediction of jump phenomena in rotationally-coupled maneuvers of aircraft, including nonlinear aerodynamic effects

NASA Technical Reports Server (NTRS)

Young, J. W.; Schy, A. A.; Johnson, K. G.

1977-01-01

An analytical method has been developed for predicting critical control inputs for which nonlinear rotational coupling may cause sudden jumps in aircraft response. The analysis includes the effect of aerodynamics which are nonlinear in angle of attack. The method involves the simultaneous solution of two polynomials in roll rate, whose coefficients are functions of angle of attack and the control inputs. Results obtained using this procedure are compared with calculated time histories to verify the validity of the method for predicting jump-like instabilities.

Study on goaf gas control technology of gob-side entry driving

NASA Astrophysics Data System (ADS)

Ren, Qihan; Yuan, Benqing; Li, Qiansi

2018-01-01

The 1112 (1) track gate roadway of Gu Qiao coal mine of Huainan mining group adopt the method of gob-side entry driving, the gas emission is large during the driving of the roadway, the gas in the goaf seriously influences the safe driving of the roadway. Equalizing method, drilling drainage method, jet grouting method and other goaf gas controlling measures has been adopted. Finally, it effectively solves the safety threat of gas in goaf to roadway driving, it provides a good reference for the gas control of the gob-side entry.

Cell fate reprogramming by control of intracellular network dynamics

NASA Astrophysics Data System (ADS)

Zanudo, Jorge G. T.; Albert, Reka

Identifying control strategies for biological networks is paramount for practical applications that involve reprogramming a cell's fate, such as disease therapeutics and stem cell reprogramming. Although the topic of controlling the dynamics of a system has a long history in control theory, most of this work is not directly applicable to intracellular networks. Here we present a network control method that integrates the structural and functional information available for intracellular networks to predict control targets. Formulated in a logical dynamic scheme, our control method takes advantage of certain function-dependent network components and their relation to steady states in order to identify control targets, which are guaranteed to drive any initial state to the target state with 100% effectiveness and need to be applied only transiently for the system to reach and stay in the desired state. We illustrate our method's potential to find intervention targets for cancer treatment and cell differentiation by applying it to a leukemia signaling network and to the network controlling the differentiation of T cells. We find that the predicted control targets are effective in a broad dynamic framework. Moreover, several of the predicted interventions are supported by experiments. This work was supported by NSF Grant PHY 1205840.

Degradation of learned skills. Effectiveness of practice methods on simulated space flight skill retention

NASA Technical Reports Server (NTRS)

Sitterley, T. E.; Berge, W. A.

1972-01-01

Manual flight control and emergency procedure task skill degradation was evaluated after time intervals of from 1 to 6 months. The tasks were associated with a simulated launch through the orbit insertion flight phase of a space vehicle. The results showed that acceptable flight control performance was retained for 2 months, rapidly deteriorating thereafter by a factor of 1.7 to 3.1 depending on the performance measure used. Procedural task performance showed unacceptable degradation after only 1 month, and exceeded an order of magnitude after 4 months. The effectiveness of static rehearsal (checklists and briefings) and dynamic warmup (simulator practice) retraining methods were compared for the two tasks. Static rehearsal effectively countered procedural skill degradation, while some combination of dynamic warmup appeared necessary for flight control skill retention. It was apparent that these differences between methods were not solely a function of task type or retraining method, but were a function of the performance measures used for each task.

Four Methods of Identifying Change in the Context of a Multiple Component Reading Intervention for Struggling Middle School Readers

ERIC Educational Resources Information Center

Frijters, Jan C.; Lovett, Maureen W.; Sevcik, Rose A.; Morris, Robin D.

2013-01-01

The results from controlled intervention research have indicated that effective reading interventions exist for children with reading difficulties. Effect sizes for older struggling readers, however, typically have not matched the large effects demonstrated with younger children. Standardized effect sizes for intervention/control comparisons…

Choosing the appropriate forecasting model for predictive parameter control.

PubMed

Aleti, Aldeida; Moser, Irene; Meedeniya, Indika; Grunske, Lars

2014-01-01

All commonly used stochastic optimisation algorithms have to be parameterised to perform effectively. Adaptive parameter control (APC) is an effective method used for this purpose. APC repeatedly adjusts parameter values during the optimisation process for optimal algorithm performance. The assignment of parameter values for a given iteration is based on previously measured performance. In recent research, time series prediction has been proposed as a method of projecting the probabilities to use for parameter value selection. In this work, we examine the suitability of a variety of prediction methods for the projection of future parameter performance based on previous data. All considered prediction methods have assumptions the time series data has to conform to for the prediction method to provide accurate projections. Looking specifically at parameters of evolutionary algorithms (EAs), we find that all standard EA parameters with the exception of population size conform largely to the assumptions made by the considered prediction methods. Evaluating the performance of these prediction methods, we find that linear regression provides the best results by a very small and statistically insignificant margin. Regardless of the prediction method, predictive parameter control outperforms state of the art parameter control methods when the performance data adheres to the assumptions made by the prediction method. When a parameter's performance data does not adhere to the assumptions made by the forecasting method, the use of prediction does not have a notable adverse impact on the algorithm's performance.

In-Service Performance and Costs of Methods to Control Urban Rail System Noise

DOT National Transportation Integrated Search

1979-12-01

This study evaluates the acoustic and economic effectiveness of five methods of controlling wheel/rail noise and vibration on urban rail transit systems, namely: rail grinding, wheel truing, resilient wheels, ring-damped wheels, and welded vs. jointe...

A new compound control method for sine-on-random mixed vibration test

NASA Astrophysics Data System (ADS)

Zhang, Buyun; Wang, Ruochen; Zeng, Falin

2017-09-01

Vibration environmental test (VET) is one of the important and effective methods to provide supports for the strength design, reliability and durability test of mechanical products. A new separation control strategy was proposed to apply in multiple-input multiple-output (MIMO) sine on random (SOR) mixed mode vibration test, which is the advanced and intensive test type of VET. As the key problem of the strategy, correlation integral method was applied to separate the mixed signals which included random and sinusoidal components. The feedback control formula of MIMO linear random vibration system was systematically deduced in frequency domain, and Jacobi control algorithm was proposed in view of the elements, such as self-spectrum, coherence, and phase of power spectral density (PSD) matrix. Based on the excessive correction of excitation in sine vibration test, compression factor was introduced to reduce the excitation correction, avoiding the destruction to vibration table or other devices. The two methods were synthesized to be applied in MIMO SOR vibration test system. In the final, verification test system with the vibration of a cantilever beam as the control object was established to verify the reliability and effectiveness of the methods proposed in the paper. The test results show that the exceeding values can be controlled in the tolerance range of references accurately, and the method can supply theory and application supports for mechanical engineering.

Adjusting for treatment switching in randomised controlled trials - A simulation study and a simplified two-stage method.

PubMed

Latimer, Nicholas R; Abrams, K R; Lambert, P C; Crowther, M J; Wailoo, A J; Morden, J P; Akehurst, R L; Campbell, M J

2017-04-01

Estimates of the overall survival benefit of new cancer treatments are often confounded by treatment switching in randomised controlled trials (RCTs) - whereby patients randomised to the control group are permitted to switch onto the experimental treatment upon disease progression. In health technology assessment, estimates of the unconfounded overall survival benefit associated with the new treatment are needed. Several switching adjustment methods have been advocated in the literature, some of which have been used in health technology assessment. However, it is unclear which methods are likely to produce least bias in realistic RCT-based scenarios. We simulated RCTs in which switching, associated with patient prognosis, was permitted. Treatment effect size and time dependency, switching proportions and disease severity were varied across scenarios. We assessed the performance of alternative adjustment methods based upon bias, coverage and mean squared error, related to the estimation of true restricted mean survival in the absence of switching in the control group. We found that when the treatment effect was not time-dependent, rank preserving structural failure time models (RPSFTM) and iterative parameter estimation methods produced low levels of bias. However, in the presence of a time-dependent treatment effect, these methods produced higher levels of bias, similar to those produced by an inverse probability of censoring weights method. The inverse probability of censoring weights and structural nested models produced high levels of bias when switching proportions exceeded 85%. A simplified two-stage Weibull method produced low bias across all scenarios and provided the treatment switching mechanism is suitable, represents an appropriate adjustment method.

Validation of an Adaptive Combustion Instability Control Method for Gas-Turbine Engines

NASA Technical Reports Server (NTRS)

Kopasakis, George; DeLaat, John C.; Chang, Clarence T.

2004-01-01

This paper describes ongoing testing of an adaptive control method to suppress high frequency thermo-acoustic instabilities like those found in lean-burning, low emission combustors that are being developed for future aircraft gas turbine engines. The method called Adaptive Sliding Phasor Averaged Control, was previously tested in an experimental rig designed to simulate a combustor with an instability of about 530 Hz. Results published earlier, and briefly presented here, demonstrated that this method was effective in suppressing the instability. Because this test rig did not exhibit a well pronounced instability, a question remained regarding the effectiveness of the control methodology when applied to a more coherent instability. To answer this question, a modified combustor rig was assembled at the NASA Glenn Research Center in Cleveland, Ohio. The modified rig exhibited a more coherent, higher amplitude instability, but at a lower frequency of about 315 Hz. Test results show that this control method successfully reduced the instability pressure of the lower frequency test rig. In addition, due to a certain phenomena discovered and reported earlier, the so called Intra-Harmonic Coupling, a dramatic suppression of the instability was achieved by focusing control on the second harmonic of the instability. These results and their implications are discussed, as well as a hypothesis describing the mechanism of intra-harmonic coupling.

Effects of a Worksite Weight-Control Programme in Obese Male Workers: A Randomized Controlled Crossover Trial

ERIC Educational Resources Information Center

Iriyama, Yae; Murayama, Nobuko

2014-01-01

Objective: We conducted a randomized controlled crossover trial to evaluate the effects of a new worksite weight-control programme designed for men with or at risk of obesity using a combination of nutrition education and nutrition environmental interventions. Subjects and methods: Male workers with or at risk of obesity were recruited for this…

An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions.

PubMed

Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz; Miveh, Mohammad Reza; Guerrero, Josep M

2017-01-01

In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method.

An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions

PubMed Central

Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz; Miveh, Mohammad Reza; Guerrero, Josep M.

2017-01-01

In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method. PMID:28192436

Multi-linear model set design based on the nonlinearity measure and H-gap metric.

PubMed

Shaghaghi, Davood; Fatehi, Alireza; Khaki-Sedigh, Ali

2017-05-01

This paper proposes a model bank selection method for a large class of nonlinear systems with wide operating ranges. In particular, nonlinearity measure and H-gap metric are used to provide an effective algorithm to design a model bank for the system. Then, the proposed model bank is accompanied with model predictive controllers to design a high performance advanced process controller. The advantage of this method is the reduction of excessive switch between models and also decrement of the computational complexity in the controller bank that can lead to performance improvement of the control system. The effectiveness of the method is verified by simulations as well as experimental studies on a pH neutralization laboratory apparatus which confirms the efficiency of the proposed algorithm. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Policy Gradient Adaptive Dynamic Programming for Data-Based Optimal Control.

PubMed

Luo, Biao; Liu, Derong; Wu, Huai-Ning; Wang, Ding; Lewis, Frank L

2017-10-01

The model-free optimal control problem of general discrete-time nonlinear systems is considered in this paper, and a data-based policy gradient adaptive dynamic programming (PGADP) algorithm is developed to design an adaptive optimal controller method. By using offline and online data rather than the mathematical system model, the PGADP algorithm improves control policy with a gradient descent scheme. The convergence of the PGADP algorithm is proved by demonstrating that the constructed Q -function sequence converges to the optimal Q -function. Based on the PGADP algorithm, the adaptive control method is developed with an actor-critic structure and the method of weighted residuals. Its convergence properties are analyzed, where the approximate Q -function converges to its optimum. Computer simulation results demonstrate the effectiveness of the PGADP-based adaptive control method.

Multiple model self-tuning control for a class of nonlinear systems

NASA Astrophysics Data System (ADS)

Huang, Miao; Wang, Xin; Wang, Zhenlei

2015-10-01

This study develops a novel nonlinear multiple model self-tuning control method for a class of nonlinear discrete-time systems. An increment system model and a modified robust adaptive law are proposed to expand the application range, thus eliminating the assumption that either the nonlinear term of the nonlinear system or its differential term is global-bounded. The nonlinear self-tuning control method can address the situation wherein the nonlinear system is not subject to a globally uniformly asymptotically stable zero dynamics by incorporating the pole-placement scheme. A novel, nonlinear control structure based on this scheme is presented to improve control precision. Stability and convergence can be confirmed when the proposed multiple model self-tuning control method is applied. Furthermore, simulation results demonstrate the effectiveness of the proposed method.

Constructing the effect of alternative intervention strategies on historic epidemics.

PubMed

Cook, A R; Gibson, G J; Gottwald, T R; Gilligan, C A

2008-10-06

Data from historical epidemics provide a vital and sometimes under-used resource from which to devise strategies for future control of disease. Previous methods for retrospective analysis of epidemics, in which alternative interventions are compared, do not make full use of the information; by using only partial information on the historical trajectory, augmentation of control may lead to predictions of a paradoxical increase in disease. Here we introduce a novel statistical approach that takes full account of the available information in constructing the effect of alternative intervention strategies in historic epidemics. The key to the method lies in identifying a suitable mapping between the historic and notional outbreaks, under alternative control strategies. We do this by using the Sellke construction as a latent process linking epidemics. We illustrate the application of the method with two examples. First, using temporal data for the common human cold, we show the improvement under the new method in the precision of predictions for different control strategies. Second, we show the generality of the method for retrospective analysis of epidemics by applying it to a spatially extended arboreal epidemic in which we demonstrate the relative effectiveness of host culling strategies that differ in frequency and spatial extent. Some of the inferential and philosophical issues that arise are discussed along with the scope of potential application of the new method.

A new decentralised controller design method for a class of strongly interconnected systems

NASA Astrophysics Data System (ADS)

Duan, Zhisheng; Jiang, Zhong-Ping; Huang, Lin

2017-02-01

In this paper, two interconnected structures are first discussed, under which some closed-loop subsystems must be unstable to make the whole interconnected system stable, which can be viewed as a kind of strongly interconnected systems. Then, comparisons with small gain theorem are discussed and large gain interconnected characteristics are shown. A new approach for the design of decentralised controllers is presented by determining the Lyapunov function structure previously, which allows the existence of unstable subsystems. By fully utilising the orthogonal space information of input matrix, some new understandings are presented for the construction of Lyapunov matrix. This new method can deal with decentralised state feedback, static output feedback and dynamic output feedback controllers in a unified framework. Furthermore, in order to reduce the design conservativeness and deal with robustness, a new robust decentralised controller design method is given by combining with the parameter-dependent Lyapunov function method. Some basic rules are provided for the choice of initial variables in Lyapunov matrix or new introduced slack matrices. As byproducts, some linear matrix inequality based sufficient conditions are established for centralised static output feedback stabilisation. Effects of unstable subsystems in nonlinear Lur'e systems are further discussed. The corresponding decentralised controller design method is presented for absolute stability. The examples illustrate that the new method is significantly effective.

Stereo Sound Field Controller Design Using Partial Model Matching on the Frequency Domain

NASA Astrophysics Data System (ADS)

Kumon, Makoto; Miike, Katsuhiro; Eguchi, Kazuki; Mizumoto, Ikuro; Iwai, Zenta

The objective of sound field control is to make the acoustic characteristics of a listening room close to those of the desired system. Conventional methods apply feedforward controllers, such as digital filters, to achieve this objective. However, feedback controllers are also necessary in order to attenuate noise or to compensate the uncertainty of the acoustic characteristics of the listening room. Since acoustic characteristics are well modeled on the frequency domain, it is efficient to design controllers with respect to frequency responses, but it is difficult to design a multi input multi output (MIMO) control system on a wide frequency domain. In the present study, a partial model matching method on the frequency domain was adopted because this method requires only sampled data, rather than complex mathematical models of the plant, in order to design controllers for MIMO systems. The partial model matching method was applied to design two-degree-of-freedom controllers for acoustic equalization and noise reduction. Experiments demonstrated effectiveness of the proposed method.

A new integrated evaluation method of heavy metals pollution control during melting and sintering of MSWI fly ash.

PubMed

Li, Rundong; Li, Yanlong; Yang, Tianhua; Wang, Lei; Wang, Weiyun

2015-05-30

Evaluations of technologies for heavy metal control mainly examine the residual and leaching rates of a single heavy metal, such that developed evaluation method have no coordination or uniqueness and are therefore unsuitable for hazard control effect evaluation. An overall pollution toxicity index (OPTI) was established in this paper, based on the developed index, an integrated evaluation method of heavy metal pollution control was established. Application of this method in the melting and sintering of fly ash revealed the following results: The integrated control efficiency of the melting process was higher in all instances than that of the sintering process. The lowest integrated control efficiency of melting was 56.2%, and the highest integrated control efficiency of sintering was 46.6%. Using the same technology, higher integrated control efficiency conditions were all achieved with lower temperatures and shorter times. This study demonstrated the unification and consistency of this method. Copyright © 2015 Elsevier B.V. All rights reserved.

Collaborative simulation method with spatiotemporal synchronization process control

NASA Astrophysics Data System (ADS)

Zou, Yisheng; Ding, Guofu; Zhang, Weihua; Zhang, Jian; Qin, Shengfeng; Tan, John Kian

2016-10-01

When designing a complex mechatronics system, such as high speed trains, it is relatively difficult to effectively simulate the entire system's dynamic behaviors because it involves multi-disciplinary subsystems. Currently,a most practical approach for multi-disciplinary simulation is interface based coupling simulation method, but it faces a twofold challenge: spatial and time unsynchronizations among multi-directional coupling simulation of subsystems. A new collaborative simulation method with spatiotemporal synchronization process control is proposed for coupling simulating a given complex mechatronics system across multiple subsystems on different platforms. The method consists of 1) a coupler-based coupling mechanisms to define the interfacing and interaction mechanisms among subsystems, and 2) a simulation process control algorithm to realize the coupling simulation in a spatiotemporal synchronized manner. The test results from a case study show that the proposed method 1) can certainly be used to simulate the sub-systems interactions under different simulation conditions in an engineering system, and 2) effectively supports multi-directional coupling simulation among multi-disciplinary subsystems. This method has been successfully applied in China high speed train design and development processes, demonstrating that it can be applied in a wide range of engineering systems design and simulation with improved efficiency and effectiveness.

Evaluating a complex system-wide intervention using the difference in differences method: the Delivering Choice Programme

PubMed Central

Round, Jeff; Drake, Robyn; Kendall, Edward; Addicott, Rachael; Agelopoulos, Nicky; Jones, Louise

2015-01-01

Objectives We report the use of difference in differences (DiD) methodology to evaluate a complex, system-wide healthcare intervention. We use the worked example of evaluating the Marie Curie Delivering Choice Programme (DCP) for advanced illness in a large urban healthcare economy. Methods DiD was selected because a randomised controlled trial was not feasible. The method allows for before and after comparison of changes that occur in an intervention site with a matched control site. This enables analysts to control for the effect of the intervention in the absence of a local control. Any policy, seasonal or other confounding effects over the test period are assumed to have occurred in a balanced way at both sites. Data were obtained from primary care trusts. Outcomes were place of death, inpatient admissions, length of stay and costs. Results Small changes were identified between pre- and post-DCP outputs in the intervention site. The proportion of home deaths and median cost increased slightly, while the number of admissions per patient and the average length of stay per admission decreased slightly. None of these changes was statistically significant. Conclusions Effects estimates were limited by small numbers accessing new services and selection bias in sample population and comparator site. In evaluating the effect of a complex healthcare intervention, the choice of analysis method and output measures is crucial. Alternatives to randomised controlled trials may be required for evaluating large scale complex interventions and the DiD approach is suitable, subject to careful selection of measured outputs and control population. PMID:24644163

Investigation of the Flutter Suppression by Fuzzy Logic Control for Hypersonic Wing

NASA Astrophysics Data System (ADS)

Li, Dongxu; Luo, Qing; Xu, Rui

This paper presents a fundamental study of flutter characteristics and control performance of an aeroelastic system based on a two-dimensional double wedge wing in the hypersonic regime. Dynamic equations were established based on the modified third order nonlinear piston theory and some nonlinear structural effects are also included. A set of important parameters are observed. And then aeroelastic control law is designed to suppress the amplitude of the LCOs for the system in the sub/supercritical speed range by applying fuzzy logic control on the input of the deflection of the flap. The overall effects of the parameters on the aeroelastic system were outlined. Nonlinear aeroelastic responses in the open- and closed-loop system are obtained through numerical methods. The simulations show fuzzy logic control methods are effective in suppressing flutter and provide a smart approach for this complicated system.

Effectiveness of Resilience Training on Ego-control and Hardiness of Illicit Drug Users

PubMed Central

Roustaei, Amin; Bakhshipoor, Babollah; Doostian, Younes; Goodiny, Ali Akbar; Koohikar, Mansoureh; Massah, Omid

2017-01-01

Background The aim of this research was to determine the effectiveness of resilience training upon ego-control and hardiness of the addicted persons. Methods This was a semi-experimental study with pretest and posttest control groups which was conducted in Sari, Iran, during 2014-2015. Thirty persons were selected among 240 illicit drug users who underwent screening. Resilience training was performed in ten sessions for the experimental group. The Kobasa hardiness questionnaire and self-restraint scale (SRS) were used for data collection and multivariate covariance test was performed for data analysis. Findings According to the data, ego-control and hardiness of participants were improved significantly by resilience training (P < 0.001). Conclusion Resilience training is effective upon the rate of ego-control and self-restraint and hardiness. This method can be used in addiction treatment clinics and residential centers. PMID:29026500

Temporal parameter change of human postural control ability during upright swing using recursive least square method

NASA Astrophysics Data System (ADS)

Goto, Akifumi; Ishida, Mizuri; Sagawa, Koichi

2010-01-01

The purpose of this study is to derive quantitative assessment indicators of the human postural control ability. An inverted pendulum is applied to standing human body and is controlled by ankle joint torque according to PD control method in sagittal plane. Torque control parameters (KP: proportional gain, KD: derivative gain) and pole placements of postural control system are estimated with time from inclination angle variation using fixed trace method as recursive least square method. Eight young healthy volunteers are participated in the experiment, in which volunteers are asked to incline forward as far as and as fast as possible 10 times over 10 [s] stationary intervals with their neck joint, hip joint and knee joint fixed, and then return to initial upright posture. The inclination angle is measured by an optical motion capture system. Three conditions are introduced to simulate unstable standing posture; 1) eyes-opened posture for healthy condition, 2) eyes-closed posture for visual impaired and 3) one-legged posture for lower-extremity muscle weakness. The estimated parameters Kp, KD and pole placements are applied to multiple comparison test among all stability conditions. The test results indicate that Kp, KD and real pole reflect effect of lower-extremity muscle weakness and KD also represents effect of visual impairment. It is suggested that the proposed method is valid for quantitative assessment of standing postural control ability.

Simulation and Experimental Investigation of Structural Dynamic Frequency Characteristics Control

PubMed Central

Zhang, Xingwu; Chen, Xuefeng; You, Shangqin; He, Zhengjia; Li, Bing

2012-01-01

In general, mechanical equipment such as cars, airplanes, and machine tools all operate with constant frequency characteristics. These constant working characteristics should be controlled if the dynamic performance of the equipment demands improvement or the dynamic characteristics is intended to change with different working conditions. Active control is a stable and beneficial method for this, but current active control methods mainly focus on vibration control for reducing the vibration amplitudes in the time domain or frequency domain. In this paper, a new method of dynamic frequency characteristics active control (DFCAC) is presented for a flat plate, which can not only accomplish vibration control but also arbitrarily change the dynamic characteristics of the equipment. The proposed DFCAC algorithm is based on a neural network including two parts of the identification implement and the controller. The effectiveness of the DFCAC method is verified by several simulation and experiments, which provide desirable results. PMID:22666072

Simulation and experimental investigation of structural dynamic frequency characteristics control.

PubMed

Zhang, Xingwu; Chen, Xuefeng; You, Shangqin; He, Zhengjia; Li, Bing

2012-01-01

In general, mechanical equipment such as cars, airplanes, and machine tools all operate with constant frequency characteristics. These constant working characteristics should be controlled if the dynamic performance of the equipment demands improvement or the dynamic characteristics is intended to change with different working conditions. Active control is a stable and beneficial method for this, but current active control methods mainly focus on vibration control for reducing the vibration amplitudes in the time domain or frequency domain. In this paper, a new method of dynamic frequency characteristics active control (DFCAC) is presented for a flat plate, which can not only accomplish vibration control but also arbitrarily change the dynamic characteristics of the equipment. The proposed DFCAC algorithm is based on a neural network including two parts of the identification implement and the controller. The effectiveness of the DFCAC method is verified by several simulation and experiments, which provide desirable results.

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

Hoke, Anderson; Shirazi, Mariko; Chakraborty, Sudipta

As deployment of power electronic coupled generation such as photovoltaic (PV) systems increases, grid operators have shown increasing interest in calling on inverter-coupled generation to help mitigate frequency contingency events by rapidly surging active power into the grid. When responding to contingency events, the faster the active power is provided, the more effective it may be for arresting the frequency event. This paper proposes a predictive PV inverter control method for very fast and accurate control of active power. This rapid active power control method will increase the effectiveness of various higher-level controls designed to mitigate grid frequency contingency events,more » including fast power-frequency droop, inertia emulation, and fast frequency response, without the need for energy storage. The rapid active power control method, coupled with a maximum power point estimation method, is implemented in a prototype PV inverter connected to a PV array. The prototype inverter's response to various frequency events is experimentally confirmed to be fast (beginning within 2 line cycles and completing within 4.5 line cycles of a severe test event) and accurate (below 2% steady-state error).« less

Robust master-slave synchronization for general uncertain delayed dynamical model based on adaptive control scheme.

PubMed

Wang, Tianbo; Zhou, Wuneng; Zhao, Shouwei; Yu, Weiqin

2014-03-01

In this paper, the robust exponential synchronization problem for a class of uncertain delayed master-slave dynamical system is investigated by using the adaptive control method. Different from some existing master-slave models, the considered master-slave system includes bounded unmodeled dynamics. In order to compensate the effect of unmodeled dynamics and effectively achieve synchronization, a novel adaptive controller with simple updated laws is proposed. Moreover, the results are given in terms of LMIs, which can be easily solved by LMI Toolbox in Matlab. A numerical example is given to illustrate the effectiveness of the method. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Highly Effective Birth Control Use Before and After Women's Incarceration.

PubMed

Ramaswamy, Megha; Chen, Hsiang-Feng; Cropsey, Karen L; Clarke, Jennifer G; Kelly, Patricia J

2015-06-01

We examined factors associated with women's use of highly effective birth control before and after incarceration, since women with ongoing criminal justice involvement bear a disproportionate burden of sexual and reproductive health problems, including high rates of unintended pregnancy and inconsistent contraceptive use. Using a longitudinal study design, we conducted surveys with 102 women in an urban midwestern jail and then followed up with 66 of them 6 months after incarceration. We used stepwise logistic regression to assess individual, interpersonal, resource-based, organizational, and environmental factors associated with utilizing highly effective birth control. Forty-two percent of women reported utilizing highly effective birth control (e.g., sterilization or other highly effective reversible methods) prior to incarceration, and 54% reported using these methods after release from jail (p<0.001). Ninety percent of women reported not wanting to get pregnant. Consistent use of birth control (p=0.001) and alcohol problems (p=0.027) were associated with utilization of highly effective birth control prior to incarceration. Previous pregnancies (p=0.012) were the only factor associated with utilization of highly effective birth control after release from jail. Clinicians and public health practitioners can use findings from this study to develop clinical and intervention efforts aimed at improving unintended-pregnancy prevention among incarcerated women both during their confinement and during the tumultuous period after their release from jail.

Researching on Control Device of Prestressing Wire Reinforcement

NASA Astrophysics Data System (ADS)

Si, Jianhui; Guo, Yangbo; Liu, Maoshe

2017-06-01

This paper mainly introduces a device for controlling prestress and its related research methods, the advantage of this method is that the reinforcement process is easy to operate and control the prestress of wire rope accurately. The relationship between the stress and strain of the steel wire rope is monitored during the experiment, and the one - to - one relationship between the controllable position and the pretightening force of the steel wire rope is confirmed by the 5mm steel wire rope, and the results are analyzed theoretically by the measured elastic modulus. The results show that the method can effectively control the prestressing force, and the result provides a reference method for strengthening the concrete column with prestressed steel strand.

The Effect of Coordinated Teaching Method Practices on Some Motor Skills of 6-Year-Old Children

ERIC Educational Resources Information Center

Altinkok, Mustafa

2017-01-01

Purpose: This study was designed to examine the effects of Coordinated Teaching Method activities applied for 10 weeks on 6-year-old children, and to examine the effects of these activities on the development of some motor skills in children. Research Methods: The "Experimental Research Model with Pre-test and Post-test Control Group"…

Nonlinear Performance Seeking Control using Fuzzy Model Reference Learning Control and the Method of Steepest Descent

NASA Technical Reports Server (NTRS)

Kopasakis, George

1997-01-01

Performance Seeking Control (PSC) attempts to find and control the process at the operating condition that will generate maximum performance. In this paper a nonlinear multivariable PSC methodology will be developed, utilizing the Fuzzy Model Reference Learning Control (FMRLC) and the method of Steepest Descent or Gradient (SDG). This PSC control methodology employs the SDG method to find the operating condition that will generate maximum performance. This operating condition is in turn passed to the FMRLC controller as a set point for the control of the process. The conventional SDG algorithm is modified in this paper in order for convergence to occur monotonically. For the FMRLC control, the conventional fuzzy model reference learning control methodology is utilized, with guidelines generated here for effective tuning of the FMRLC controller.

Effects of the Menstrual Cycle and Oral Contraception on Singers' Pitch Control

ERIC Educational Resources Information Center

La, Filipa M. B.; Sundberg, Johan; Howard, David M.; Sa-Couto, Pedro; Freitas, Adelaide

2012-01-01

Purpose: Difficulties with intonation and vibrato control during the menstrual cycle have been reported by singers; however, this phenomenon has not yet been systematically investigated. Method: A double-blind randomized placebo-controlled trial assessing effects of the menstrual cycle and use of a combined oral contraceptive pill (OCP) on pitch…

Force analysis of magnetic bearings with power-saving controls

NASA Technical Reports Server (NTRS)

Johnson, Dexter; Brown, Gerald V.; Inman, Daniel J.

1992-01-01

Most magnetic bearing control schemes use a bias current with a superimposed control current to linearize the relationship between the control current and the force it delivers. For most operating conditions, the existence of the bias current requires more power than alternative methods that do not use conventional bias. Two such methods are examined which diminish or eliminate bias current. In the typical bias control scheme it is found that for a harmonic control force command into a voltage limited transconductance amplifier, the desired force output is obtained only up to certain combinations of force amplitude and frequency. Above these values, the force amplitude is reduced and a phase lag occurs. The power saving alternative control schemes typically exhibit such deficiencies at even lower command frequencies and amplitudes. To assess the severity of these effects, a time history analysis of the force output is performed for the bias method and the alternative methods. Results of the analysis show that the alternative approaches may be viable. The various control methods examined were mathematically modeled using nondimensionalized variables to facilitate comparison of the various methods.

Systematic methods for the design of a class of fuzzy logic controllers

NASA Astrophysics Data System (ADS)

Yasin, Saad Yaser

2002-09-01

Fuzzy logic control, a relatively new branch of control, can be used effectively whenever conventional control techniques become inapplicable or impractical. Various attempts have been made to create a generalized fuzzy control system and to formulate an analytically based fuzzy control law. In this study, two methods, the left and right parameterization method and the normalized spline-base membership function method, were utilized for formulating analytical fuzzy control laws in important practical control applications. The first model was used to design an idle speed controller, while the second was used to control an inverted control problem. The results of both showed that a fuzzy logic control system based on the developed models could be used effectively to control highly nonlinear and complex systems. This study also investigated the application of fuzzy control in areas not fully utilizing fuzzy logic control. Three important practical applications pertaining to the automotive industries were studied. The first automotive-related application was the idle speed of spark ignition engines, using two fuzzy control methods: (1) left and right parameterization, and (2) fuzzy clustering techniques and experimental data. The simulation and experimental results showed that a conventional controller-like performance fuzzy controller could be designed based only on experimental data and intuitive knowledge of the system. In the second application, the automotive cruise control problem, a fuzzy control model was developed using parameters adaptive Proportional plus Integral plus Derivative (PID)-type fuzzy logic controller. Results were comparable to those using linearized conventional PID and linear quadratic regulator (LQR) controllers and, in certain cases and conditions, the developed controller outperformed the conventional PID and LQR controllers. The third application involved the air/fuel ratio control problem, using fuzzy clustering techniques, experimental data, and a conversion algorithm, to develop a fuzzy-based control algorithm. Results were similar to those obtained by recently published conventional control based studies. The influence of the fuzzy inference operators and parameters on performance and stability of the fuzzy logic controller was studied Results indicated that, the selections of certain parameters or combinations of parameters, affect greatly the performance and stability of the fuzzy controller. Diagnostic guidelines used to tune or change certain factors or parameters to improve controller performance were developed based on knowledge gained from conventional control methods and knowledge gained from the experimental and the simulation results of this study.

Integral force feedback control with input shaping: Application to piezo-based scanning systems in ECDLs.

PubMed

Zhang, Meng; Liu, Zhigang; Zhu, Yu; Bu, Mingfan; Hong, Jun

2017-07-01

In this paper, a hybrid control system is developed by integrating the closed-loop force feedback and input shaping method to overcome the problem of the hysteresis and dynamic behavior in piezo-based scanning systems and increase the scanning speed of tunable external cavity diode lasers. The flexible hinge and piezoelectric actuators are analyzed, and a dynamic model of the scanning systems is established. A force sensor and an integral controller are utilized in integral force feedback (IFF) to directly augment the damping of the piezoelectric scanning systems. Hysteresis has been effectively eliminated, but the mechanical resonance is still evident. Noticeable residual vibration occurred after the inflection points and then gradually disappeared. For the further control of mechanical resonance, based on the theory of minimum-acceleration trajectory planning, the time-domain input shaping method was developed. The turning sections of a scanning trajectory are replaced by smooth curves, while the linear sections are retained. The IFF method is combined with the input shaping method to control the non-linearity and mechanical resonance in high-speed piezo-based scanning systems. Experiments are conducted, and the results demonstrate the effectiveness of the proposed control approach.

Integral force feedback control with input shaping: Application to piezo-based scanning systems in ECDLs

NASA Astrophysics Data System (ADS)

Zhang, Meng; Liu, Zhigang; Zhu, Yu; Bu, Mingfan; Hong, Jun

2017-07-01

In this paper, a hybrid control system is developed by integrating the closed-loop force feedback and input shaping method to overcome the problem of the hysteresis and dynamic behavior in piezo-based scanning systems and increase the scanning speed of tunable external cavity diode lasers. The flexible hinge and piezoelectric actuators are analyzed, and a dynamic model of the scanning systems is established. A force sensor and an integral controller are utilized in integral force feedback (IFF) to directly augment the damping of the piezoelectric scanning systems. Hysteresis has been effectively eliminated, but the mechanical resonance is still evident. Noticeable residual vibration occurred after the inflection points and then gradually disappeared. For the further control of mechanical resonance, based on the theory of minimum-acceleration trajectory planning, the time-domain input shaping method was developed. The turning sections of a scanning trajectory are replaced by smooth curves, while the linear sections are retained. The IFF method is combined with the input shaping method to control the non-linearity and mechanical resonance in high-speed piezo-based scanning systems. Experiments are conducted, and the results demonstrate the effectiveness of the proposed control approach.

Adaptive Actor-Critic Design-Based Integral Sliding-Mode Control for Partially Unknown Nonlinear Systems With Input Disturbances.

PubMed

Fan, Quan-Yong; Yang, Guang-Hong

2016-01-01

This paper is concerned with the problem of integral sliding-mode control for a class of nonlinear systems with input disturbances and unknown nonlinear terms through the adaptive actor-critic (AC) control method. The main objective is to design a sliding-mode control methodology based on the adaptive dynamic programming (ADP) method, so that the closed-loop system with time-varying disturbances is stable and the nearly optimal performance of the sliding-mode dynamics can be guaranteed. In the first step, a neural network (NN)-based observer and a disturbance observer are designed to approximate the unknown nonlinear terms and estimate the input disturbances, respectively. Based on the NN approximations and disturbance estimations, the discontinuous part of the sliding-mode control is constructed to eliminate the effect of the disturbances and attain the expected equivalent sliding-mode dynamics. Then, the ADP method with AC structure is presented to learn the optimal control for the sliding-mode dynamics online. Reconstructed tuning laws are developed to guarantee the stability of the sliding-mode dynamics and the convergence of the weights of critic and actor NNs. Finally, the simulation results are presented to illustrate the effectiveness of the proposed method.

Sterility method of pest control and its potential role in an integrated sea lamprey (Petromyzon marinus) control program

USGS Publications Warehouse

Hanson, Lee H.; Manion, Patrick J.

1980-01-01

The sterility method of pest control could be an effective tool in the sea lamprey (Petromyzon marinus) control program in the Great Lakes. Some of the requirements for its successful application have been met. A field study demonstrated that the release of male sea lampreys, sterilized by the injection of 100 mg/kg of P,P-bis(1-aziridinyl)-N-methylphosphinothioic amide (bisazir), will reduce the number of viable larvae produced. The actual reduction in reproductive success that occurred was directly related to the ratio of sterile to normal males in the population. The technique can be used in many ways in an integrated control program and has considerable potential for the more effective control of the sea lamprey. Eradication is a distinct possibility.Key words: sea lamprey, Petromyzon marinus; pest control, fish control, sterile-male technique, sterilization, chemosterilants, bisazir, Great Lakes

Entanglement-assisted quantum feedback control

NASA Astrophysics Data System (ADS)

Yamamoto, Naoki; Mikami, Tomoaki

2017-07-01

The main advantage of quantum metrology relies on the effective use of entanglement, which indeed allows us to achieve strictly better estimation performance over the standard quantum limit. In this paper, we propose an analogous method utilizing entanglement for the purpose of feedback control. The system considered is a general linear dynamical quantum system, where the control goal can be systematically formulated as a linear quadratic Gaussian control problem based on the quantum Kalman filtering method; in this setting, an entangled input probe field is effectively used to reduce the estimation error and accordingly the control cost function. In particular, we show that, in the problem of cooling an opto-mechanical oscillator, the entanglement-assisted feedback control can lower the stationary occupation number of the oscillator below the limit attainable by the controller with a coherent probe field and furthermore beats the controller with an optimized squeezed probe field.

Improving Control System Cyber-State Awareness using Known Secure Sensor Measurements

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

Ondrej Linda; Milos Manic; Miles McQueen

Abstract—This paper presents design and simulation of a low cost and low false alarm rate method for improved cyber-state awareness of critical control systems - the Known Secure Sensor Measurements (KSSM) method. The KSSM concept relies on physical measurements to detect malicious falsification of the control systems state. The KSSM method can be incrementally integrated with already installed control systems for enhanced resilience. This paper reviews the previously developed theoretical KSSM concept and then describes a simulation of the KSSM system. A simulated control system network is integrated with the KSSM components. The effectiveness of detection of various intrusion scenariosmore » is demonstrated on several control system network topologies.« less

Tine cultivation effects on weed control, productivity, and economics of peanut under organic management

USDA-ARS?s Scientific Manuscript database

Identifying effective weed control regimes for organic peanut has become paramount for improving the feasibility of organic production. Tine cultivation is a proven effective method at reducing in-row weed populations in several crops. Field trials were therefore conducted in 2008 and 2009 to asse...

Inventory Management for Irregular Shipment of Goods in Distribution Centre

NASA Astrophysics Data System (ADS)

Takeda, Hitoshi; Kitaoka, Masatoshi; Usuki, Jun

2016-01-01

The shipping amount of commodity goods (Foods, confectionery, dairy products, such as public cosmetic pharmaceutical products) changes irregularly at the distribution center dealing with the general consumer goods. Because the shipment time and the amount of the shipment are irregular, the demand forecast becomes very difficult. For this, the inventory control becomes difficult, too. It cannot be applied to the shipment of the commodity by the conventional inventory control methods. This paper proposes the method for inventory control by cumulative flow curve method. It proposed the method of deciding the order quantity of the inventory control by the cumulative flow curve. Here, it proposes three methods. 1) Power method,2) Polynomial method and 3)Revised Holt's linear method that forecasts data with trends that is a kind of exponential smoothing method. This paper compares the economics of the conventional method, which is managed by the experienced and three new proposed methods. And, the effectiveness of the proposal method is verified from the numerical calculations.

High-accuracy resolver-to-digital conversion via phase locked loop based on PID controller

NASA Astrophysics Data System (ADS)

Li, Yaoling; Wu, Zhong

2018-03-01

The problem of resolver-to-digital conversion (RDC) is transformed into the problem of angle tracking control, and a phase locked loop (PLL) method based on PID controller is proposed in this paper. This controller comprises a typical PI controller plus an incomplete differential which can avoid the amplification of higher-frequency noise components by filtering the phase detection error with a low-pass filter. Compared with conventional ones, the proposed PLL method makes the converter a system of type III and thus the conversion accuracy can be improved. Experimental results demonstrate the effectiveness of the proposed method.

Testing For EM Upsets In Aircraft Control Computers

NASA Technical Reports Server (NTRS)

Belcastro, Celeste M.

1994-01-01

Effects of transient electrical signals evaluated in laboratory tests. Method of evaluating nominally fault-tolerant, aircraft-type digital-computer-based control system devised. Provides for evaluation of susceptibility of system to upset and evaluation of integrity of control when system subjected to transient electrical signals like those induced by electromagnetic (EM) source, in this case lightning. Beyond aerospace applications, fault-tolerant control systems becoming more wide-spread in industry; such as in automobiles. Method supports practical, systematic tests for evaluation of designs of fault-tolerant control systems.

Direct torque control method applied to the WECS based on the PMSG and controlled with backstepping approach

NASA Astrophysics Data System (ADS)

Errami, Youssef; Obbadi, Abdellatif; Sahnoun, Smail; Ouassaid, Mohammed; Maaroufi, Mohamed

2018-05-01

This paper proposes a Direct Torque Control (DTC) method for Wind Power System (WPS) based Permanent Magnet Synchronous Generator (PMSG) and Backstepping approach. In this work, generator side and grid-side converter with filter are used as the interface between the wind turbine and grid. Backstepping approach demonstrates great performance in complicated nonlinear systems control such as WPS. So, the control method combines the DTC to achieve Maximum Power Point Tracking (MPPT) and Backstepping approach to sustain the DC-bus voltage and to regulate the grid-side power factor. In addition, control strategy is developed in the sense of Lyapunov stability theorem for the WPS. Simulation results using MATLAB/Simulink validate the effectiveness of the proposed controllers.

Quantifying relative importance: Computing standardized effects in models with binary outcomes

USGS Publications Warehouse

Grace, James B.; Johnson, Darren; Lefcheck, Jonathan S.; Byrnes, Jarrett E.K.

2018-01-01

Results from simulation studies show that both the LT and OE methods of standardization support a similarly-broad range of coefficient comparisons. The LT method estimates effects that reflect underlying latent-linear propensities, while the OE method computes a linear approximation for the effects of predictors on binary responses. The contrast between assumptions for the two methods is reflected in persistently weaker standardized effects associated with OE standardization. Reliance on standard deviations for standardization (the traditional approach) is critically examined and shown to introduce substantial biases when predictors are non-Gaussian. The use of relevant ranges in place of standard deviations has the capacity to place LT and OE standardized coefficients on a more comparable scale. As ecologists address increasingly complex hypotheses, especially those that involve comparing the influences of different controlling factors (e.g., top-down versus bottom-up or biotic versus abiotic controls), comparable coefficients become a necessary component for evaluations.

USER'S GUIDE: EMISSION CONTROL TECHNOLOGIES AND EMISSION FACTORS FOR UNPAVED ROAD FUGITIVE EMISSIONS

EPA Science Inventory

This document assists control agency personnel in evaluating unpaved road fugitive emissions control plans and helps industry personnel develop effective control strategies for unpaved roads. he brochure describes control techniques for reducing unpaved road emissions and methods...

The effectiveness of different methods of toilet training for bowel and bladder control.

PubMed Central

Klassen, Terry P; Kiddoo, Darcie; Lang, Mia E; Friesen, Carol; Russell, Kelly; Spooner, Carol; Vandermeer, Ben

2006-01-01

OBJECTIVES The objectives of this report are to determine the following: (1) the effectiveness of the toilet training methods, (2) which factors modify the effectiveness of toilet training, (3) if the toilet training methods are risk factor for adverse outcomes, and (4) the optimal toilet training method for achieving bowel and bladder control among patients with special needs. DATA SOURCES MEDLINE, Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid OLDMEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, CINAHL, PsycINFO, ERIC, EBM Reviews, HealthSTAR, AMED, Web of Science, Biological Abstracts, Sociological Abstracts, OCLC ProceedingsFirst, OCLC PapersFirst, Dissertation Abstracts, Index to Theses, National Research Register's Projects Database, and trials registers. REVIEW METHODS Two reviewers assessed the studies for inclusion. Studies were included if they met the following criteria: STUDY DESIGN RCT, CCT, prospective or retrospective cohort, case-control, cross-sectional or case-series; POPULATION infants, toddlers, or children with or without co-morbidities, neuromuscular, cognitive, or behavioral handicaps disabilities; INTERVENTION at least one toilet training method; and OUTCOME bladder and/or bowel control, successes, failures, adverse outcomes. Methodological quality was assessed independently by two reviewers. Data were extracted by one reviewer and a second checked for accuracy and completeness. Due to substantial heterogeneity, meta-analysis was not possible. RESULTS Twenty-six observational studies and eight controlled trials were included. Approximately half of the studies examined healthy children while the remaining studies assessed toilet training of mentally or physically handicapped children. For healthy children, the Azrin and Foxx method performed better than the Spock method, while child-oriented combined with negative term avoidance proved better than without. For mentally handicapped children, individual training was superior to group methods; relaxation techniques proved more efficacious than standard methods; operant conditioning was better than conventional treatment, and the Azrin and Foxx and a behavior modification method fared better than no training. The child-oriented approach was not assessed among mentally handicapped children. For children with Hirschsprung's disease or anal atresia, a multi-disciplinary behavior treatment was more efficacious than no treatment. CONCLUSIONS Both the Azrin and Foxx method and the child-oriented approach resulted in quick, successful toilet training, but there was limited information about the sustainability of the training. The two methods were not directly compared, thus it is difficult to draw definitive conclusions regarding the superiority of one method over the other. In general, both programs may be used to teach toilet training to healthy children. The Azrin and Foxx method and operant conditioning methods were consistently effective for toilet training mentally handicapped children. Programs that were adapted to physically handicapped children also resulted in successful toilet training. A lack of data precluded conclusions regarding the development of adverse outcomes. PMID:17764212

The application of neural network PID controller to control the light gasoline etherification

NASA Astrophysics Data System (ADS)

Cheng, Huanxin; Zhang, Yimin; Kong, Lingling; Meng, Xiangyong

2017-06-01

Light gasoline etherification technology can effectively improve the quality of gasoline, which is environmental- friendly and economical. By combining BP neural network and PID control and using BP neural network self-learning ability for online parameter tuning, this method optimizes the parameters of PID controller and applies this to the Fcc gas flow control to achieve the control of the final product- heavy oil concentration. Finally, through MATLAB simulation, it is found that the PID control based on BP neural network has better controlling effect than traditional PID control.

Nonlinear analysis of switched semi-active controlled systems

NASA Astrophysics Data System (ADS)

Eslaminasab, Nima; Vahid A., Orang; Golnaraghi, Farid

2011-02-01

Semi-active systems improve suspension performance of the vehicles more effectively than conventional passive systems by simultaneously improving ride comfort and road handling. Also, because of size, weight, price and performance advantages, they have gained more interest over the active as well as passive systems. Probably the most neglected aspect of the semi-active on-off control systems and strategies is the effects of the added nonlinearities of those systems, which are introduced and analysed in this paper. To do so, numerical techniques, analytical method of averaging and experimental analysis are deployed. In this paper, a new method to analyse, calculate and compare the performances of the semi-active controlled systems is proposed; further, a new controller based on the observations of actual test data is proposed to eliminate the adverse effects of added nonlinearities. The significance of the proposed new system is the simplicity of the algorithm and ease of implementation. In fact, this new semi-active control strategy could be easily adopted and used with most of the existing semi-active control systems.

Interval type-2 fuzzy PID controller for uncertain nonlinear inverted pendulum system.

PubMed

El-Bardini, Mohammad; El-Nagar, Ahmad M

2014-05-01

In this paper, the interval type-2 fuzzy proportional-integral-derivative controller (IT2F-PID) is proposed for controlling an inverted pendulum on a cart system with an uncertain model. The proposed controller is designed using a new method of type-reduction that we have proposed, which is called the simplified type-reduction method. The proposed IT2F-PID controller is able to handle the effect of structure uncertainties due to the structure of the interval type-2 fuzzy logic system (IT2-FLS). The results of the proposed IT2F-PID controller using a new method of type-reduction are compared with the other proposed IT2F-PID controller using the uncertainty bound method and the type-1 fuzzy PID controller (T1F-PID). The simulation and practical results show that the performance of the proposed controller is significantly improved compared with the T1F-PID controller. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Nonlinear Decoupling Control With ANFIS-Based Unmodeled Dynamics Compensation for a Class of Complex Industrial Processes.

PubMed

Zhang, Yajun; Chai, Tianyou; Wang, Hong; Wang, Dianhui; Chen, Xinkai

2018-06-01

Complex industrial processes are multivariable and generally exhibit strong coupling among their control loops with heavy nonlinear nature. These make it very difficult to obtain an accurate model. As a result, the conventional and data-driven control methods are difficult to apply. Using a twin-tank level control system as an example, a novel multivariable decoupling control algorithm with adaptive neural-fuzzy inference system (ANFIS)-based unmodeled dynamics (UD) compensation is proposed in this paper for a class of complex industrial processes. At first, a nonlinear multivariable decoupling controller with UD compensation is introduced. Different from the existing methods, the decomposition estimation algorithm using ANFIS is employed to estimate the UD, and the desired estimating and decoupling control effects are achieved. Second, the proposed method does not require the complicated switching mechanism which has been commonly used in the literature. This significantly simplifies the obtained decoupling algorithm and its realization. Third, based on some new lemmas and theorems, the conditions on the stability and convergence of the closed-loop system are analyzed to show the uniform boundedness of all the variables. This is then followed by the summary on experimental tests on a heavily coupled nonlinear twin-tank system that demonstrates the effectiveness and the practicability of the proposed method.

Decision support for evidence-based integration of disease control: A proof of concept for malaria and schistosomiasis

PubMed Central

Graeden, Ellie; Kerr, Justin; Sorrell, Erin M.; Katz, Rebecca

2018-01-01

Managing infectious disease requires rapid and effective response to support decision making. The decisions are complex and require understanding of the diseases, disease intervention and control measures, and the disease-relevant characteristics of the local community. Though disease modeling frameworks have been developed to address these questions, the complexity of current models presents a significant barrier to community-level decision makers in using the outputs of the most scientifically robust methods to support pragmatic decisions about implementing a public health response effort, even for endemic diseases with which they are already familiar. Here, we describe the development of an application available on the internet, including from mobile devices, with a simple user interface, to support on-the-ground decision-making for integrating disease control programs, given local conditions and practical constraints. The model upon which the tool is built provides predictive analysis for the effectiveness of integration of schistosomiasis and malaria control, two diseases with extensive geographical and epidemiological overlap, and which result in significant morbidity and mortality in affected regions. Working with data from countries across sub-Saharan Africa and the Middle East, we present a proof-of-principle method and corresponding prototype tool to provide guidance on how to optimize integration of vertical disease control programs. This method and tool demonstrate significant progress in effectively translating the best available scientific models to support practical decision making on the ground with the potential to significantly increase the efficacy and cost-effectiveness of disease control. Author summary Designing and implementing effective programs for infectious disease control requires complex decision-making, informed by an understanding of the diseases, the types of disease interventions and control measures available, and the disease-relevant characteristics of the local community. Though disease modeling frameworks have been developed to address these questions and support decision-making, the complexity of current models presents a significant barrier to on-the-ground end users. The picture is further complicated when considering approaches for integration of different disease control programs, where co-infection dynamics, treatment interactions, and other variables must also be taken into account. Here, we describe the development of an application available on the internet with a simple user interface, to support on-the-ground decision-making for integrating disease control, given local conditions and practical constraints. The model upon which the tool is built provides predictive analysis for the effectiveness of integration of schistosomiasis and malaria control, two diseases with extensive geographical and epidemiological overlap. This proof-of-concept method and tool demonstrate significant progress in effectively translating the best available scientific models to support pragmatic decision-making on the ground, with the potential to significantly increase the impact and cost-effectiveness of disease control. PMID:29649260

Flux-Feedback Magnetic-Suspension Actuator

NASA Technical Reports Server (NTRS)

Groom, Nelson J.

1990-01-01

Flux-feedback magnetic-suspension actuator provides magnetic suspension and control forces having linear transfer characteristics between force command and force output over large range of gaps. Hall-effect devices used as sensors for electronic feedback circuit controlling currents flowing in electromagnetic windings to maintain flux linking suspended element at substantially constant value independent of changes in length of gap. Technique provides effective method for maintenance of constant flux density in gap and simpler than previous methods. Applications include magnetic actuators for control of shapes and figures of antennas and of precise segmented reflectors, magnetic suspensions in devices for storage of angular momentum and/or kinetic energy, and systems for control, pointing, and isolation of instruments.

Power factor regulation for household usage

NASA Astrophysics Data System (ADS)

Daud, Nik Ghazali Nik; Hashim, Fakroul Ridzuan; Tarmizi, Muhammad Haziq Ahmad

2018-02-01

Power factor regulator technology has recently drawn attention to the consumer and to power generation company in order for consumers to use electricity efficiently. Controlling of power factor for efficient usage can reduce the production of power in fulfilment demands hence reducing the greenhouse effect. This paper presents the design method of power factor controller for household usage. There are several methods to improve the power factor. The power factor controller used by this method is by using capacitors. Total harmonic distortion also has become a major problem for the reliability of the electrical appliances and techniques to control it will be discussed.

Slip Ratio Estimation and Regenerative Brake Control for Decelerating Electric Vehicles without Detection of Vehicle Velocity and Acceleration

NASA Astrophysics Data System (ADS)

Suzuki, Toru; Fujimoto, Hiroshi

In slip ratio control systems, it is necessary to detect the vehicle velocity in order to obtain the slip ratio. However, it is very difficult to measure this velocity directly. We have proposed slip ratio estimation and control methods that do not require the vehicle velocity with acceleration. In this paper, the slip ratio estimation and control methods are proposed without detecting the vehicle velocity and acceleration when it is decelerating. We carried out simulations and experiments by using an electric vehicle to verify the effectiveness of the proposed method.

Controller design approach based on linear programming.

PubMed

Tanaka, Ryo; Shibasaki, Hiroki; Ogawa, Hiromitsu; Murakami, Takahiro; Ishida, Yoshihisa

2013-11-01

This study explains and demonstrates the design method for a control system with a load disturbance observer. Observer gains are determined by linear programming (LP) in terms of the Routh-Hurwitz stability criterion and the final-value theorem. In addition, the control model has a feedback structure, and feedback gains are determined to be the linear quadratic regulator. The simulation results confirmed that compared with the conventional method, the output estimated by our proposed method converges to a reference input faster when a load disturbance is added to a control system. In addition, we also confirmed the effectiveness of the proposed method by performing an experiment with a DC motor. © 2013 ISA. Published by ISA. All rights reserved.

A performance analysis method for distributed real-time robotic systems: A case study of remote teleoperation

NASA Technical Reports Server (NTRS)

Lefebvre, D. R.; Sanderson, A. C.

1994-01-01

Robot coordination and control systems for remote teleoperation applications are by necessity implemented on distributed computers. Modeling and performance analysis of these distributed robotic systems is difficult, but important for economic system design. Performance analysis methods originally developed for conventional distributed computer systems are often unsatisfactory for evaluating real-time systems. The paper introduces a formal model of distributed robotic control systems; and a performance analysis method, based on scheduling theory, which can handle concurrent hard-real-time response specifications. Use of the method is illustrated by a case of remote teleoperation which assesses the effect of communication delays and the allocation of robot control functions on control system hardware requirements.

[Regional atmospheric environment risk source identification and assessment].

PubMed

Zhang, Xiao-Chun; Chen, Wei-Ping; Ma, Chun; Zhan, Shui-Fen; Jiao, Wen-Tao

2012-12-01

Identification and assessment for atmospheric environment risk source plays an important role in regional atmospheric risk assessment and regional atmospheric pollution prevention and control. The likelihood exposure and consequence assessment method (LEC method) and the Delphi method were employed to build a fast and effective method for identification and assessment of regional atmospheric environment risk sources. This method was applied to the case study of a large coal transportation port in North China. The assessment results showed that the risk characteristics and the harm degree of regional atmospheric environment risk source were in line with the actual situation. Fast and effective identification and assessment of risk source has laid an important foundation for the regional atmospheric environmental risk assessment and regional atmospheric pollution prevention and control.

Optimization of controllability and robustness of complex networks by edge directionality

NASA Astrophysics Data System (ADS)

Liang, Man; Jin, Suoqin; Wang, Dingjie; Zou, Xiufen

2016-09-01

Recently, controllability of complex networks has attracted enormous attention in various fields of science and engineering. How to optimize structural controllability has also become a significant issue. Previous studies have shown that an appropriate directional assignment can improve structural controllability; however, the evolution of the structural controllability of complex networks under attacks and cascading has always been ignored. To address this problem, this study proposes a new edge orientation method (NEOM) based on residual degree that changes the link direction while conserving topology and directionality. By comparing the results with those of previous methods in two random graph models and several realistic networks, our proposed approach is demonstrated to be an effective and competitive method for improving the structural controllability of complex networks. Moreover, numerical simulations show that our method is near-optimal in optimizing structural controllability. Strikingly, compared to the original network, our method maintains the structural controllability of the network under attacks and cascading, indicating that the NEOM can also enhance the robustness of controllability of networks. These results alter the view of the nature of controllability in complex networks, change the understanding of structural controllability and affect the design of network models to control such networks.

Self-optimizing Pitch Control for Large Scale Wind Turbine Based on ADRC

NASA Astrophysics Data System (ADS)

Xia, Anjun; Hu, Guoqing; Li, Zheng; Huang, Dongxiao; Wang, Fengxiang

2018-01-01

Since wind turbine is a complex nonlinear and strong coupling system, traditional PI control method can hardly achieve good control performance. A self-optimizing pitch control method based on the active-disturbance-rejection control theory is proposed in this paper. A linear model of the wind turbine is derived by linearizing the aerodynamic torque equation and the dynamic response of wind turbine is transformed into a first-order linear system. An expert system is designed to optimize the amplification coefficient according to the pitch rate and the speed deviation. The purpose of the proposed control method is to regulate the amplification coefficient automatically and keep the variations of pitch rate and rotor speed in proper ranges. Simulation results show that the proposed pitch control method has the ability to modify the amplification coefficient effectively, when it is not suitable, and keep the variations of pitch rate and rotor speed in proper ranges

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.

The effectiveness of different methods of toilet training for bowel and bladder control.

PubMed

Klassen, Terry P; Kiddoo, Darcie; Lang, Mia E; Friesen, Carol; Russell, Kelly; Spooner, Carol; Vandermeer, Ben

2006-12-01

The objectives of this report are to determine the following: (1) the effectiveness of the toilet training methods, (2) which factors modify the effectiveness of toilet training, (3) if the toilet training methods are risk factor for adverse outcomes, and (4) the optimal toilet training method for achieving bowel and bladder control among patients with special needs. MEDLINE, Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid OLDMEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, CINAHL, PsycINFO, ERIC, EBM Reviews, HealthSTAR, AMED, Web of Science, Biological Abstracts, Sociological Abstracts, OCLC ProceedingsFirst, OCLC PapersFirst, Dissertation Abstracts, Index to Theses, National Research Register's Projects Database, and trials registers. Two reviewers assessed the studies for inclusion. Studies were included if they met the following criteria: RCT, CCT, prospective or retrospective cohort, case-control, cross-sectional or case-series; infants, toddlers, or children with or without co-morbidities, neuromuscular, cognitive, or behavioral handicaps disabilities; at least one toilet training method; and bladder and/or bowel control, successes, failures, adverse outcomes. Methodological quality was assessed independently by two reviewers. Data were extracted by one reviewer and a second checked for accuracy and completeness. Due to substantial heterogeneity, meta-analysis was not possible. Twenty-six observational studies and eight controlled trials were included. Approximately half of the studies examined healthy children while the remaining studies assessed toilet training of mentally or physically handicapped children. For healthy children, the Azrin and Foxx method performed better than the Spock method, while child-oriented combined with negative term avoidance proved better than without. For mentally handicapped children, individual training was superior to group methods; relaxation techniques proved more efficacious than standard methods; operant conditioning was better than conventional treatment, and the Azrin and Foxx and a behavior modification method fared better than no training. The child-oriented approach was not assessed among mentally handicapped children. For children with Hirschsprung's disease or anal atresia, a multi-disciplinary behavior treatment was more efficacious than no treatment. Both the Azrin and Foxx method and the child-oriented approach resulted in quick, successful toilet training, but there was limited information about the sustainability of the training. The two methods were not directly compared, thus it is difficult to draw definitive conclusions regarding the superiority of one method over the other. In general, both programs may be used to teach toilet training to healthy children. The Azrin and Foxx method and operant conditioning methods were consistently effective for toilet training mentally handicapped children. Programs that were adapted to physically handicapped children also resulted in successful toilet training. A lack of data precluded conclusions regarding the development of adverse outcomes.

Design and application of an inertial impactor in combination with an ATP bioluminescence detector for in situ rapid estimation of the efficacies of air controlling devices on removal of bioaerosols.

PubMed

Yoon, Ki Young; Park, Chul Woo; Byeon, Jeong Hoon; Hwang, Jungho

2010-03-01

We proposed a rapid method to estimate the efficacies of air controlling devices in situ using ATP bioluminescence in combination with an inertial impactor. The inertial impactor was designed to have 1 mum of cutoff diameter, and its performance was estimated analytically, numerically, and experimentally. The proposed method was characterized using Staphylococcus epidermidis, which was aerosolized with a nebulizer. The bioaerosol concentrations were estimated within 25 min using the proposed method without a culturing process, which requires several days for colony formation. A linear relationship was obtained between the results of the proposed ATP method (RLU/m(3)) and the conventional culture-based method (CFU/m(3)), with R(2) 0.9283. The proposed method was applied to estimate the concentration of indoor bioaerosols, which were identified as a mixture of various microbial species including bacteria, fungi, and actinomycetes, in an occupational indoor environment, controlled by mechanical ventilation and an air cleaner. Consequently, the proposed method showed a linearity with the culture-based method for indoor bioaerosols with R(2) 0.8189, even though various kinds of microorganisms existed in the indoor air. The proposed method may be effective in monitoring the changes of relative concentration of indoor bioaerosols and estimating the effectiveness of air control devices in indoor environments.

Gait Retraining With Real-Time Biofeedback to Reduce Knee Adduction Moment: Systematic Review of Effects and Methods Used.

PubMed

Richards, Rosie; van den Noort, Josien C; Dekker, Joost; Harlaar, Jaap

2017-01-01

To review the current literature regarding methods and effects of real-time biofeedback used as a method for gait retraining to reduce knee adduction moment (KAM), with intended application for patients with knee osteoarthritis (KOA). Searches were conducted in MEDLINE, Embase, CINAHL, SPORTDiscus, Web of Science, and Cochrane Central Register of Controlled Trials with the keywords gait, feedback, and knee osteoarthritis from inception to May 2015. Titles and abstracts were screened by 1 individual for studies aiming to reduce KAM. Full-text articles were assessed by 2 individuals against predefined criteria. Data were extracted by 1 individual according to a predefined list, including participant demographics and training methods and effects. Electronic searches resulted in 190 potentially eligible studies, from which 12 met all inclusion criteria. Within-group standardized mean differences (SMDs) for reduction of KAM in healthy controls ranged from .44 to 2.47 and from .29 to .37 in patients with KOA. In patients with KOA, improvements were reported in pain and function, with SMDs ranging from .55 to 1.16. Methods of implementation of biofeedback training varied between studies, but in healthy controls increased KAM reduction was noted with implicit, rather than explicit, instructions. This review suggests that biofeedback gait training is effective primarily for reducing KAM but also for reducing pain and improving function in patients with KOA. The review was limited by the small number of studies featuring patients with KOA and the lack of controlled studies. The results suggest there is value and a need in further researching biofeedback training for reducing KAM. Future studies should include larger cohorts of patients, long-term follow-up, and controlled trials. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

A New Low-frequency Sonophoresis System Combined with Ultrasonic Motor and Transducer

NASA Astrophysics Data System (ADS)

Zhu, Pancheng; Peng, Hanmin; Yang, Jianzhi; Mao, Ting; Sheng, Juan

2018-03-01

Low frequency sonophoresis (LFS) is currently being attempted as a transdermal drug delivery method in clinical areas. However, it lacks both an effective control method and the equipment to satisfy the varying drug dosage requirements of individual patients. Herein, a novel method aimed at controlling permeability is proposed and developed, using a pressure control strategy which is based on an accurate, adjustable and non-invasive ultrasound transdermal drug delivery system in in vitro LFS. The system mainly consists of a lead screw linear ultrasonic motor and an ultrasonic transducer, in which the former offers pressure and the latter provides ultrasound wave in the liquid. The ultrasound can enhance non-invasive permeation and the pressure from the motor can control the permeability. The calculated and experimental results demonstrate that the maximum pressure on artificial skin is under the area with the maximum vibration amplitude of the ultrasonic transducer, and the total pressure consists of acoustic pressure from the transducer and approximate static pressure from the motor. Changing the static pressure from the ultrasonic motor can effectively control the non-invasive permeability, by adjusting the duty ratio or the amplitude of the motor’s driving voltage. In addition, the permeability control of calcein by thrust control is realized in 15 min, indicating the suitability of this method for application in accurate medical technology. The obtained results reveal that the issue of difficult permeability control can be addressed, using this control method in in vitro LFS to open up a route to the design of accurate drug delivery technology for individual patients.

Child-Parent Interventions for Childhood Anxiety Disorders: A Systematic Review and Meta-Analysis

ERIC Educational Resources Information Center

Brendel, Kristen Esposito; Maynard, Brandy R.

2014-01-01

Objective: This study compared the effects of direct child-parent interventions to the effects of child-focused interventions on anxiety outcomes for children with anxiety disorders. Method: Systematic review methods and meta-analytic techniques were employed. Eight randomized controlled trials examining effects of family cognitive behavior…

Informing new or improved vector control tools for reducing the malaria burden in Tanzania: a qualitative exploration of perceptions of mosquitoes and methods for their control among the residents of Dar es Salaam.

PubMed

Makungu, Christina; Stephen, Stephania; Kumburu, Salome; Govella, Nicodem J; Dongus, Stefan; Hildon, Zoe Jane-Lara; Killeen, Gerry F; Jones, Caroline

2017-10-11

The effectiveness of malaria prevention with long-lasting insecticidal nets and indoor residual spraying is limited by emerging insecticide resistance, evasive mosquito behaviours that include outdoor biting, sub-optimal implementation and inappropriate use. New vector control interventions are required and their potential effectiveness will be enhanced if existing household perceptions and practices are integrated into intervention design. This qualitative descriptive study used focus groups discussions, in-depth interviews and photovoice methods to explore mosquito control perceptions and practices among residents in four study sites in Dar es Salaam, Tanzania. Mosquitoes were perceived as a growing problem, directly attributed to widespread environmental deterioration and lack of effective mosquito control interventions. Malaria and nuisance biting were perceived as the main problem caused by mosquitoes. Breeding sites were clearly distinguished from resting sites but residents did not differentiate between habitats producing malaria vector mosquitoes and others producing mostly nuisance mosquitoes. The most frequently mentioned protection methods in the wealthiest locations were bed nets, aerosol insecticide sprays, window screens, and fumigation, while bed nets were most frequently mentioned and described as 'part of the culture' in the least wealthy locations. Mosquito-proofed housing was consistently viewed as desirable, but considered unaffordable outside wealthiest locations. Slapping and covering up with clothing were most commonly used to prevent biting outdoors. Despite their utility outdoors, topical repellents applied to the skin were considered expensive, and viewed with suspicion due to perceived side effects. Improving the local environment was the preferred method for preventing outdoor biting. Affordability, effectiveness, availability, practicality, as well as social influences, such as government recommendations, socialization and internalization (familiarization and habit) were described as key factors influencing uptake. Outdoor transmission is widely accepted as an obstacle to malaria elimination. Larval source management, targeting both malaria vectors and nuisance-biting mosquitoes, is the preferred method for mosquito control among the residents of Dar es Salaam and should be prioritized for development alongside new methods for outdoor personal protection. Even if made available, effective and affordable, these additional interventions may require time and user experience to achieve positive reputations and trustworthiness.

[Montessori method applied to dementia - literature review].

PubMed

Brandão, Daniela Filipa Soares; Martín, José Ignacio

2012-06-01

The Montessori method was initially applied to children, but now it has also been applied to people with dementia. The purpose of this study is to systematically review the research on the effectiveness of this method using Medical Literature Analysis and Retrieval System Online (Medline) with the keywords dementia and Montessori method. We selected lo studies, in which there were significant improvements in participation and constructive engagement, and reduction of negative affects and passive engagement. Nevertheless, systematic reviews about this non-pharmacological intervention in dementia rate this method as weak in terms of effectiveness. This apparent discrepancy can be explained because the Montessori method may have, in fact, a small influence on dimensions such as behavioral problems, or because there is no research about this method with high levels of control, such as the presence of several control groups or a double-blind study.

Design of a robust fuzzy controller for the arc stability of CO(2) welding process using the Taguchi method.

PubMed

Kim, Dongcheol; Rhee, Sehun

2002-01-01

CO(2) welding is a complex process. Weld quality is dependent on arc stability and minimizing the effects of disturbances or changes in the operating condition commonly occurring during the welding process. In order to minimize these effects, a controller can be used. In this study, a fuzzy controller was used in order to stabilize the arc during CO(2) welding. The input variable of the controller was the Mita index. This index estimates quantitatively the arc stability that is influenced by many welding process parameters. Because the welding process is complex, a mathematical model of the Mita index was difficult to derive. Therefore, the parameter settings of the fuzzy controller were determined by performing actual control experiments without using a mathematical model of the controlled process. The solution, the Taguchi method was used to determine the optimal control parameter settings of the fuzzy controller to make the control performance robust and insensitive to the changes in the operating conditions.

The art and science of flow control

NASA Technical Reports Server (NTRS)

Gad-El-hak, Mohamed

1989-01-01

The ability to actively or passively manipulate a flow field to effect a desired change is of immense technological importance. In this article, methods of control to achieve transition delay, separation postponement, lift enhancement, drag reduction, turbulence augmentation, or noise suppression are considered. Emphasis is placed on external boundary-layer flows although applicability of some of the methods reviewed for internal flows will be mentioned. Attempts will be made to present a unified view of the different methods of control to achieve a variety of end results. Performance penalties associated with a particular method such as cost, complexity, or trade-off will be elaborated.

Optimal control for a tuberculosis model with undetected cases in Cameroon

NASA Astrophysics Data System (ADS)

Moualeu, D. P.; Weiser, M.; Ehrig, R.; Deuflhard, P.

2015-03-01

This paper considers the optimal control of tuberculosis through education, diagnosis campaign and chemoprophylaxis of latently infected. A mathematical model which includes important components such as undiagnosed infectious, diagnosed infectious, latently infected and lost-sight infectious is formulated. The model combines a frequency dependent and a density dependent force of infection for TB transmission. Through optimal control theory and numerical simulations, a cost-effective balance of two different intervention methods is obtained. Seeking to minimize the amount of money the government spends when tuberculosis remain endemic in the Cameroonian population, Pontryagin's maximum principle is used to characterize the optimal control. The optimality system is derived and solved numerically using the forward-backward sweep method (FBSM). Results provide a framework for designing cost-effective strategies for diseases with multiple intervention methods. It comes out that combining chemoprophylaxis and education, the burden of TB can be reduced by 80% in 10 years.

Closed-loop and robust control of quantum systems.

PubMed

Chen, Chunlin; Wang, Lin-Cheng; Wang, Yuanlong

2013-01-01

For most practical quantum control systems, it is important and difficult to attain robustness and reliability due to unavoidable uncertainties in the system dynamics or models. Three kinds of typical approaches (e.g., closed-loop learning control, feedback control, and robust control) have been proved to be effective to solve these problems. This work presents a self-contained survey on the closed-loop and robust control of quantum systems, as well as a brief introduction to a selection of basic theories and methods in this research area, to provide interested readers with a general idea for further studies. In the area of closed-loop learning control of quantum systems, we survey and introduce such learning control methods as gradient-based methods, genetic algorithms (GA), and reinforcement learning (RL) methods from a unified point of view of exploring the quantum control landscapes. For the feedback control approach, the paper surveys three control strategies including Lyapunov control, measurement-based control, and coherent-feedback control. Then such topics in the field of quantum robust control as H(∞) control, sliding mode control, quantum risk-sensitive control, and quantum ensemble control are reviewed. The paper concludes with a perspective of future research directions that are likely to attract more attention.

Hierarchical Shared Control of Cane-Type Walking-Aid Robot

PubMed Central

Tao, Chunjing

2017-01-01

A hierarchical shared-control method of the walking-aid robot for both human motion intention recognition and the obstacle emergency-avoidance method based on artificial potential field (APF) is proposed in this paper. The human motion intention is obtained from the interaction force measurements of the sensory system composed of 4 force-sensing registers (FSR) and a torque sensor. Meanwhile, a laser-range finder (LRF) forward is applied to detect the obstacles and try to guide the operator based on the repulsion force calculated by artificial potential field. An obstacle emergency-avoidance method which comprises different control strategies is also assumed according to the different states of obstacles or emergency cases. To ensure the user's safety, the hierarchical shared-control method combines the intention recognition method with the obstacle emergency-avoidance method based on the distance between the walking-aid robot and the obstacles. At last, experiments validate the effectiveness of the proposed hierarchical shared-control method. PMID:29093805

Contamination Control in Hybrid Microelectronic Modules. Part 1: Identification of Critical Process and Contaminants

NASA Technical Reports Server (NTRS)

Himmel, R. P.

1975-01-01

Various hybrid processing steps, handling procedures, and materials are examined in an attempt to identify sources of contamination and to propose methods for the control of these contaminants. It is found that package sealing, assembly, and rework are especially susceptible to contamination. Moisture and loose particles are identified as the worst contaminants. The points at which contaminants are most likely to enter the hybrid package are also identified, and both general and specific methods for their detection and control are developed. In general, the most effective controls for contaminants are: clean working areas, visual inspection at each step of the process, and effective cleaning at critical process steps. Specific methods suggested include the detection of loose particles by a precap visual inspection, by preseal and post-seal electrical testing, and by a particle impact noise test. Moisture is best controlled by sealing all packages in a clean, dry, inert atmosphere after a thorough bake-out of all parts.

The effects of an anchovy (stolephorus insularis) substrate application on the level of fluor intrusion on Sprague Dawley rat teeth (in vivo)

NASA Astrophysics Data System (ADS)

Sakinah, N. R.; Gunawan, H. A.; Puspitawati, R.

2017-08-01

Fluoride intrusion is one of the efficacy parameters of fluoridation. Anchovy (Stolephorus insularis), which contains a high fluoride concentration in the CaF2compound, can be used as a fluoridative agent which is affordable and easily obtained. The aim of this study is to prove the effectiveness of the application of an anchovy substrate (Stolephorus insularis), either by a feeding method or a topical method, for tooth fluoridation based on the depth of fluoride intrusion on the enamel. An in vivo experimental laboratory method was used. The subjects were 14 Sprague Dawley rats divided into five groups. The groups included a baseline control, a feeding negative control, a topical negative control, an anchovy feeding method, and a topical solution anchovy method. After 15 days of treatment, the teeth were cut transversely with a 0.5 mm thickness then processed to test for fluoride intrusion using fluorescence microscopy. There was increased fluor intrusion on the enamel of the experimental groups compared to the negative control groups (p<0.05).Fluoride intrusion using the topical fluoride method is higher than with the feeding method (p <0.05). Thus, the application of an anchovy substrate, either by chewing or smearing, increases fluoride intrusion on the enamel.

Strategies for the synthesis of supported gold palladium nanoparticles with controlled morphology and composition.

PubMed

Hutchings, Graham J; Kiely, Christopher J

2013-08-20

The discovery that supported gold nanoparticles are exceptionally effective catalysts for redox reactions has led to an explosion of interest in gold nanoparticles. In addition, incorporating a second metal as an alloy with gold can enhance the catalyst performance even more. The addition of small amounts of gold to palladium, in particular, and vice versa significantly enhances the activity of supported gold-palladium nanoparticles as redox catalysts through what researchers believe is an electronic effect. In this Account, we describe and discuss methodologies for the synthesis of supported gold-palladium nanoparticles and their use as heterogeneous catalysts. In general, three key challenges need to be addressed in the synthesis of bimetallic nanoparticles: (i) control of the particle morphology, (ii) control of the particle size distribution, and (iii) control of the nanoparticle composition. We describe three methodologies to address these challenges. First, we discuss the relatively simple method of coimpregnation. Impregnation allows control of particle morphology during alloy formation but does not control the particle compositions or the particle size distribution. Even so, we contend that this method is the best preparation method in the catalyst discovery phase of any project, since it permits the investigation of many different catalyst structures in one experiment, which may aid the identification of new catalysts. A second approach, sol-immobilization, allows enhanced control of the particle size distribution and the particle morphology, but control of the composition of individual nanoparticles is not possible. Finally, a modified impregnation method can allow the control of all three of these crucial parameters. We discuss the effect of the different methodologies on three redox reactions: benzyl alcohol oxidation, toluene oxidation, and the direct synthesis of hydrogen peroxide. We show that the coimpregnation method provides the best reaction selectivity for benzyl alcohol oxidation and the direct synthesis of hydrogen peroxide. However, because of the reaction mechanism, the sol-immobilzation method gives very active and selective catalysts for toluene oxidation. We discuss the possible nature of the preferred active structures of the supported nanoparticles for these reactions. This paper is based on the IACS Heinz Heinemann Award Lecture entitled "Catalysis using gold nanoparticles" which was given in Munich in July 2012.

Randomized Controlled Trial in Clinical Settings to Evaluate Effectiveness of Coping Skills Education Used with Progressive Tinnitus Management

ERIC Educational Resources Information Center

Henry, James A.; Thielman, Emily J.; Zaugg, Tara L.; Kaelin, Christine; Schmidt, Caroline J.; Griest, Susan; McMillan, Garnett P.; Myers, Paula; Rivera, Izel; Baldwin, Robert; Carlson, Kathleen

2017-01-01

Purpose: This randomized controlled trial evaluated, within clinical settings, the effectiveness of coping skills education that is provided with progressive tinnitus management (PTM). Method: At 2 Veterans Affairs medical centers, N = 300 veterans were randomized to either PTM intervention or 6-month wait-list control. The PTM intervention…

Effects of a Controlled Family-Based Health Education/Counseling Intervention

ERIC Educational Resources Information Center

Salminen, Marika; Vahlberg, Tero; Ojanlatva, Ansa; Kivela, Sirkka-Liisa

2005-01-01

Objective: To describe the effects of a controlled family-based health education/counseling intervention on health behaviors of children with a familial history of cardiovascular diseases (FH-CVDs). Methods: The intervention group (IG, n=432) received 5 counseling sessions. The control groups 1 (CG1, n=200) and 2 (CG2, n=423) received no…

Combustion Control System Design of Diesel Engine via ASPR based Output Feedback Control Strategy with a PFC

NASA Astrophysics Data System (ADS)

Mizumoto, Ikuro; Tsunematsu, Junpei; Fujii, Seiya

2016-09-01

In this paper, a design method of an output feedback control system with a simple feedforward input for a combustion model of diesel engine will be proposed based on the almost strictly positive real-ness (ASPR-ness) of the controlled system for a combustion control of diesel engines. A parallel feedforward compensator (PFC) design scheme which renders the resulting augmented controlled system ASPR will also be proposed in order to design a stable output feedback control system for the considered combustion model. The effectiveness of our proposed method will be confirmed through numerical simulations.

Experiments study on attitude coupling control method for flexible spacecraft

NASA Astrophysics Data System (ADS)

Wang, Jie; Li, Dongxu

2018-06-01

High pointing accuracy and stabilization are significant for spacecrafts to carry out Earth observing, laser communication and space exploration missions. However, when a spacecraft undergoes large angle maneuver, the excited elastic oscillation of flexible appendages, for instance, solar wing and onboard antenna, would downgrade the performance of the spacecraft platform. This paper proposes a coupling control method, which synthesizes the adaptive sliding mode controller and the positive position feedback (PPF) controller, to control the attitude and suppress the elastic vibration simultaneously. Because of its prominent performance for attitude tracking and stabilization, the proposed method is capable of slewing the flexible spacecraft with a large angle. Also, the method is robust to parametric uncertainties of the spacecraft model. Numerical simulations are carried out with a hub-plate system which undergoes a single-axis attitude maneuver. An attitude control testbed for the flexible spacecraft is established and experiments are conducted to validate the coupling control method. Both numerical and experimental results demonstrate that the method discussed above can effectively decrease the stabilization time and improve the attitude accuracy of the flexible spacecraft.

Effects of antibacterial primers with quaternary ammonium and nano-silver on S. mutans impregnated in human dentin blocks

PubMed Central

Cheng, Lei; Zhang, Ke; Weir, Michael D.; Liu, Huaibing; Zhou, Xuedong; Xu, Hockin H. K.

2013-01-01

Objectives Recent studies developed antibacterial bonding agents and composites containing a quaternary ammonium dimethacrylate (QADM) and nanoparticles of silver (NAg). The objectives of this study were to investigate: (1) the effect of antibacterial primers containing QADM and NAg on the inhibition of Streptococcus mutans (S. mutans) impregnated into dentin blocks for the first time, and (2) the effect of QADM or NAg alone or in combination, and the effect of NAg mass fraction, on S. mutans viability in dentin. Methods Scotchbond Multi-Purpose (SBMP) bonding agent was used. QADM and NAg were incorporated into SBMP primer. Six primers were tested: SBMP primer control, control + 10% QADM (mass %), control + 0.05% NAg, control + 10% QADM + 0.05% NAg, control + 0.1% NAg, and control + 10% QADM + 0.1% NAg. S. mutans were impregnated into dentin blocks, then a primer was applied. The viable colony-forming units (CFU) were then measured by harvesting the bacteria in dentin using a sonication method. Results Control + 10% QADM + 0.1% NAg had bacteria inhibition zone 8-fold that of control (p < 0.05). The sonication method successfully harvested bacteria from dentin blocks. Control + 10% QADM + 0.1% NAg inhibited S. mutans in dentin blocks, reducing the viable CFU in dentin by three orders of magnitude, compared to control dentin without primer. Using QADM+NAg was more effective than QADM alone. Higher NAg content increased the potency. Dentin shear bond strength was similar for all groups (p > 0.1). Significance Antibacterial primer with QADM and NAg were shown to inhibit the S. mutans impregnated into dentin blocks for the first time. Bonding agent containing QADM and NAg is promising to eradicate bacteria in tooth cavity and inhibit caries. The QADM and NAg may have applicability to other adhesives, cements, sealants and composites. PMID:23422420

A novel vibration measurement and active control method for a hinged flexible two-connected piezoelectric plate

NASA Astrophysics Data System (ADS)

Qiu, Zhi-cheng; Wang, Xian-feng; Zhang, Xian-Min; Liu, Jin-guo

2018-07-01

A novel non-contact vibration measurement method using binocular vision sensors is proposed for piezoelectric flexible hinged plate. Decoupling methods of the bending and torsional low frequency vibration on measurement and driving control are investigated, using binocular vision sensors and piezoelectric actuators. A radial basis function neural network controller (RBFNNC) is designed to suppress both the larger and the smaller amplitude vibrations. To verify the non-contact measurement method and the designed controller, an experimental setup of the flexible hinged plate with binocular vision is constructed. Experiments on vibration measurement and control are conducted by using binocular vision sensors and the designed RBFNNC controllers, compared with the classical proportional and derivative (PD) control algorithm. The experimental measurement results demonstrate that the binocular vision sensors can detect the low-frequency bending and torsional vibration effectively. Furthermore, the designed RBF can suppress the bending vibration more quickly than the designed PD controller owing to the adjustment of the RBF control, especially for the small amplitude residual vibrations.

A data driven control method for structure vibration suppression

NASA Astrophysics Data System (ADS)

Xie, Yangmin; Wang, Chao; Shi, Hang; Shi, Junwei

2018-02-01

High radio-frequency space applications have motivated continuous research on vibration suppression of large space structures both in academia and industry. This paper introduces a novel data driven control method to suppress vibrations of flexible structures and experimentally validates the suppression performance. Unlike model-based control approaches, the data driven control method designs a controller directly from the input-output test data of the structure, without requiring parametric dynamics and hence free of system modeling. It utilizes the discrete frequency response via spectral analysis technique and formulates a non-convex optimization problem to obtain optimized controller parameters with a predefined controller structure. Such approach is then experimentally applied on an end-driving flexible beam-mass structure. The experiment results show that the presented method can achieve competitive disturbance rejections compared to a model-based mixed sensitivity controller under the same design criterion but with much less orders and design efforts, demonstrating the proposed data driven control is an effective approach for vibration suppression of flexible structures.

Evaluation of the Inertial Response of Variable-Speed Wind Turbines Using Advanced Simulation

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

Scholbrock, Andrew K; Muljadi, Eduard; Gevorgian, Vahan

In this paper, we focus on the temporary frequency support effect provided by wind turbine generators (WTGs) through the inertial response. With the implemented inertial control methods, the WTG is capable of increasing its active power output by releasing parts of the stored kinetic energy when the frequency excursion occurs. The active power can be boosted temporarily above the maximum power points, but the rotor speed deceleration follows and an active power output deficiency occurs during the restoration of rotor kinetic energy. We evaluate and compare the inertial response induced by two distinct inertial control methods using advanced simulation. Inmore » the first stage, the proposed inertial control methods are analyzed in offline simulation. Using an advanced wind turbine simulation program, FAST with TurbSim, the response of the researched wind turbine is comprehensively evaluated under turbulent wind conditions, and the impact on the turbine mechanical components are assessed. In the second stage, the inertial control is deployed on a real 600kW wind turbine - Controls Advanced Research Turbine, 3-bladed (CART3), which further verifies the inertial control through a hardware-in-the-loop (HIL) simulation. Various inertial control methods can be effectively evaluated based on the proposed two-stage simulation platform, which combines the offline simulation and real-time HIL simulation. The simulation results also provide insights in designing inertial control for WTGs.« less

Review of manual control methods for handheld maneuverable instruments.

PubMed

Fan, Chunman; Dodou, Dimitra; Breedveld, Paul

2013-06-01

By the introduction of new technologies, surgical procedures have been varying from free access in open surgery towards limited access in minimal access surgery. Improving access to difficult-to-reach anatomic sites, e.g. in neurosurgery or percutaneous interventions, needs advanced maneuverable instrumentation. Advances in maneuverable technology require the development of dedicated methods enabling surgeons to stay in direct, manual control of these complex instruments. This article gives an overview of the state-of-the-art in the development of manual control methods for handheld maneuverable instruments. It categorizes the manual control methods in three levels: a) number of steerable segments, b) number of Degrees Of Freedom (DOF), and c) coupling between control motion of the handle and steering motion of the tip. The literature research was completed by using Web of Science, Scopus and PubMed. The study shows that in controlling single steerable segments, direct as well as indirect control methods have been developed, whereas in controlling multiple steerable segments, a gradual shift can be noticed from parallel and serial control to integrated control. The development of multi-segmented maneuverable instruments is still at an early stage, and an intuitive and effective method to control them has to become a primary focus in the domain of minimal access surgery.

Method of laser beam coding for control systems

NASA Astrophysics Data System (ADS)

Pałys, Tomasz; Arciuch, Artur; Walczak, Andrzej; Murawski, Krzysztof

2017-08-01

The article presents the method of encoding a laser beam for control systems. The experiments were performed using a red laser emitting source with a wavelength of λ = 650 nm and a power of P ≍ 3 mW. The aim of the study was to develop methods of modulation and demodulation of the laser beam. Results of research, in which we determined the effect of selected camera parameters, such as image resolution, number of frames per second on the result of demodulation of optical signal, is also shown in the paper. The experiments showed that the adopted coding method provides sufficient information encoded in a single laser beam (36 codes with the effectiveness of decoding at 99.9%).

Using Synthetic Controls to Evaluate the Effect of Unique Interventions: The Case of Say Yes to Education.

PubMed

Bifulco, Robert; Rubenstein, Ross; Sohn, Hosung

2017-12-01

"Place-based" scholarships seek to improve student outcomes in urban school districts and promote urban revitalization in economically challenged cities. Say Yes to Education is a unique district-wide school reform effort adopted in Syracuse, NY, in 2008. It includes full-tuition scholarships for public and private universities, coupled with extensive wraparound support services in schools. This study uses synthetic control methods to evaluate the effect of Say Yes on district enrollment and graduation rates. It also introduces the synthetic control method and provides guidance for its use in evaluating single-site interventions. Combining school district-level data from the National Center for Education Statistics' Common Core of Data and New York State School Report Cards, this article uses synthetic control methods to construct a synthetic comparison district to estimate counterfactual enrollment and graduation trends for Syracuse. We find that Say Yes to Education was associated with enrollment increases in the Syracuse City School District, a district that had previously experienced decades of sustained enrollment declines. We do not find consistent evidence of changes in graduation rates following adoption of the program. Graduation rate analyses demonstrate that estimates of treatment effects can be sensitive to choices that the researcher has to make in applying synthetic control methods, particularly when pretreatment outcome measures appear to have considerable amounts of noise.

Enhanced individual selection for selecting fast growing fish: the "PROSPER" method, with application on brown trout (Salmo trutta fario)

PubMed Central

Chevassus, Bernard; Quillet, Edwige; Krieg, Francine; Hollebecq, Marie-Gwénola; Mambrini, Muriel; Fauré, André; Labbé, Laurent; Hiseux, Jean-Pierre; Vandeputte, Marc

2004-01-01

Growth rate is the main breeding goal of fish breeders, but individual selection has often shown poor responses in fish species. The PROSPER method was developed to overcome possible factors that may contribute to this low success, using (1) a variable base population and high number of breeders (Ne > 100), (2) selection within groups with low non-genetic effects and (3) repeated growth challenges. Using calculations, we show that individual selection within groups, with appropriate management of maternal effects, can be superior to mass selection as soon as the maternal effect ratio exceeds 0.15, when heritability is 0.25. Practically, brown trout were selected on length at the age of one year with the PROSPER method. The genetic gain was evaluated against an unselected control line. After four generations, the mean response per generation in length at one year was 6.2% of the control mean, while the mean correlated response in weight was 21.5% of the control mean per generation. At the 4th generation, selected fish also appeared to be leaner than control fish when compared at the same size, and the response on weight was maximal (≈130% of the control mean) between 386 and 470 days post fertilisation. This high response is promising, however, the key points of the method have to be investigated in more detail. PMID:15496285

Mass casualty tracking with air traffic control methodologies.

PubMed

Hoskins, Jason D; Graham, Ross F; Robinson, Duane R; Lutz, Clifford C; Folio, Les R

2009-06-01

An intrahospital casualty throughput system modeled after air traffic control (ATC) tracking procedures was tested in mass casualty exercises. ATC uses a simple tactile process involving informational progress strips representing each aircraft, which are held in bays representing each stage of flight to prioritize and manage aircraft. These strips can be reordered within the bays to indicate a change in priority of aircraft sequence. In this study, a similar system was designed for patient tracking. We compared the ATC model and traditional casualty tracking methods of paper and clipboard in 18 four-hour casualty scenarios, each with 5 to 30 mock casualties. The experimental and control groups were alternated to maximize exposure and minimize training effects. Results were analyzed with Mann-Whitney statistical analysis with p value < 0.05 (two-sided). The ATC method had significantly (p = 0.017) fewer errors in critical patient data (eg, name, social security number, diagnosis). Specifically, the ATC method better tracked the mechanism of injury, working diagnosis, and disposition of patients. The ATC method also performed considerably better with patient accountability during mass casualty scenarios. Data strips were comparable with the control method in terms of ease of use. In addition, participants preferred the ATC method to the control (p = 0.003) and preferred using the ATC method (p = 0.003) to traditional methods in the future. The ATC model more effectively tracked patient data with fewer errors when compared with the clipboard method. Application of these principles can enhance trauma management and can have application in civilian and military trauma centers and emergency rooms.

Vibration suppression of planar truss structures utilizing uniform damping control

NASA Technical Reports Server (NTRS)

Andersen, G. C.; Silverberg, L. M.

1986-01-01

A variety of methods has been devised for vibrational control of a structure using both passive and active controls. Presented in this paper is a relatively new method for vibration suppression, uniform damping control. This method consists of implementing a control law which tends to dampen each vibrational mode of the structure at the same desirable exponential rate. The unique aspects of this method are that the control law is not explicitly dependent on the structural stiffness, the control forces are directly proportional to the distribution of the structural mass, and the control law is natural and decentralized. The control law was applied to a flexible planar truss structure and the various aspects of implementation of the control law examined are: actuator/sensor number, placement, and the impact of the actuator/sensor number and placement on the necessary control 'power' requirements such as peak power loads, total power requirements, etc. Also examined are the effects of using a limited number of active members in terms of the vibrational performance when compared with the 'ideal' distributed control law.

A multi-factor designation method for mapping particulate-pollution control zones in China.

PubMed

Qin, Y; Xie, S D

2011-09-01

A multi-factor designation method for mapping particulate-pollution control zones was brought out through synthetically considering PM(10) pollution status, PM(10) anthropogenic emissions, fine particle pollution, long-range transport and economic situation. According to this method, China was divided into four different particulate-pollution control regions: PM Suspended Control Region, PM(10) Pollution Control Region, PM(2.5) Pollution Control Region and PM(10) and PM(2.5) Common Control Region, which accounted for 69.55%, 9.66%, 4.67% and 16.13% of China's territory, respectively. The PM(10) and PM(2.5) Common Control Region was mainly distributed in Bohai Region, Yangtze River Delta, Pearl River Delta, eastern of Sichuan province and Chongqing municipality, calling for immediate control of both PM(10) and PM(2.5). Cost-effective control effects can be achieved through concentrating efforts on PM(10) and PM(2.5) Common Control Region to address 60.32% of national PM(10) anthropogenic emissions. Air quality in districts belonging to PM(2.5) Pollution Control Region suggested that Chinese national ambient air quality standard for PM(10) was not strict enough. The result derived from application to China proved that this approach was feasible for mapping pollution control regions for a country with vast territory, complicated pollution characteristics and limited available monitoring data. Copyright © 2011 Elsevier B.V. All rights reserved.

A computer program to generate two-dimensional grids about airfoils and other shapes by the use of Poisson's equation

NASA Technical Reports Server (NTRS)

Sorenson, R. L.

1980-01-01

A method for generating two dimensional finite difference grids about airfoils and other shapes by the use of the Poisson differential equation is developed. The inhomogeneous terms are automatically chosen such that two important effects are imposed on the grid at both the inner and outer boundaries. The first effect is control of the spacing between mesh points along mesh lines intersecting the boundaries. The second effect is control of the angles with which mesh lines intersect the boundaries. A FORTRAN computer program has been written to use this method. A description of the program, a discussion of the control parameters, and a set of sample cases are included.

Combining control measures for more effective management of fisheries under uncertainty: quotas, effort limitation and protected areas.

PubMed

Stefansson, Gunnar; Rosenberg, Andrew A

2005-01-29

We consider combinations of three types of control measures for the management of fisheries when the input information for policy decisions is uncertain. The methods considered include effort controls, catch quotas and area closures. We simulated a hypothetical fishery loosely based on the Icelandic cod fishery, using a simple spatially explicit dynamic model. We compared the performance with respect to conserving the resource and economic return for each type of control measure alone and in combination. In general, combining more than one type of primary direct control on fishing provides a greater buffer to uncertainty than any single form of fishery control alone. Combining catch quota control with a large closed area is a most effective system for reducing the risk of stock collapse and maintaining both short and long-term economic performance. Effort controls can also be improved by adding closed areas to the management scheme. We recommend that multiple control methods be used wherever possible and that closed areas should be used to buffer uncertainty. To be effective, these closed areas must be large and exclude all principal gears to provide real protection from fishing mortality.

Combining control measures for more effective management of fisheries under uncertainty: quotas, effort limitation and protected areas

PubMed Central

Stefansson, Gunnar; Rosenberg, Andrew A.

2005-01-01

We consider combinations of three types of control measures for the management of fisheries when the input information for policy decisions is uncertain. The methods considered include effort controls, catch quotas and area closures. We simulated a hypothetical fishery loosely based on the Icelandic cod fishery, using a simple spatially explicit dynamic model. We compared the performance with respect to conserving the resource and economic return for each type of control measure alone and in combination. In general, combining more than one type of primary direct control on fishing provides a greater buffer to uncertainty than any single form of fishery control alone. Combining catch quota control with a large closed area is a most effective system for reducing the risk of stock collapse and maintaining both short and long-term economic performance. Effort controls can also be improved by adding closed areas to the management scheme. We recommend that multiple control methods be used wherever possible and that closed areas should be used to buffer uncertainty. To be effective, these closed areas must be large and exclude all principal gears to provide real protection from fishing mortality. PMID:15713593

Wetware, Hardware, or Software Incapacitation: Observational Methods to Determine When Autonomy Should Assume Control

NASA Technical Reports Server (NTRS)

Trujillo, Anna C.; Gregory, Irene M.

2014-01-01

Control-theoretic modeling of human operator's dynamic behavior in manual control tasks has a long, rich history. There has been significant work on techniques used to identify the pilot model of a given structure. This research attempts to go beyond pilot identification based on experimental data to develop a predictor of pilot behavior. Two methods for pre-dicting pilot stick input during changing aircraft dynamics and deducing changes in pilot behavior are presented This approach may also have the capability to detect a change in a subject due to workload, engagement, etc., or the effects of changes in vehicle dynamics on the pilot. With this ability to detect changes in piloting behavior, the possibility now exists to mediate human adverse behaviors, hardware failures, and software anomalies with autono-my that may ameliorate these undesirable effects. However, appropriate timing of when au-tonomy should assume control is dependent on criticality of actions to safety, sensitivity of methods to accurately detect these adverse changes, and effects of changes in levels of auto-mation of the system as a whole.

Wavefront control in adaptive microscopy using Shack-Hartmann sensors with arbitrarily shaped pupils.

PubMed

Dong, Bing; Booth, Martin J

2018-01-22

In adaptive optical microscopy of thick biological tissue, strong scattering and aberrations can change the effective pupil shape by rendering some Shack-Hartmann spots unusable. The change of pupil shape leads to a change of wavefront reconstruction or control matrix that should be updated accordingly. Modified slope and modal wavefront control methods based on measurements of a Shack-Hartmann wavefront sensor are proposed to accommodate an arbitrarily shaped pupil. Furthermore, we present partial wavefront control methods that remove specific aberration modes like tip, tilt and defocus from the control loop. The proposed control methods were investigated and compared by simulation using experimentally obtained aberration data. The performance was then tested experimentally through closed-loop aberration corrections using an obscured pupil.

Tuning fuzzy PD and PI controllers using reinforcement learning.

PubMed

Boubertakh, Hamid; Tadjine, Mohamed; Glorennec, Pierre-Yves; Labiod, Salim

2010-10-01

In this paper, we propose a new auto-tuning fuzzy PD and PI controllers using reinforcement Q-learning (QL) algorithm for SISO (single-input single-output) and TITO (two-input two-output) systems. We first, investigate the design parameters and settings of a typical class of Fuzzy PD (FPD) and Fuzzy PI (FPI) controllers: zero-order Takagi-Sugeno controllers with equidistant triangular membership functions for inputs, equidistant singleton membership functions for output, Larsen's implication method, and average sum defuzzification method. Secondly, the analytical structures of these typical fuzzy PD and PI controllers are compared to their classical counterpart PD and PI controllers. Finally, the effectiveness of the proposed method is proven through simulation examples. Copyright © 2010 ISA. Published by Elsevier Ltd. All rights reserved.

Control strategy of grid-connected photovoltaic generation system based on GMPPT method

NASA Astrophysics Data System (ADS)

Wang, Zhongfeng; Zhang, Xuyang; Hu, Bo; Liu, Jun; Li, Ligang; Gu, Yongqiang; Zhou, Bowen

2018-02-01

There are multiple local maximum power points when photovoltaic (PV) array runs under partial shading condition (PSC).However, the traditional maximum power point tracking (MPPT) algorithm might be easily trapped in local maximum power points (MPPs) and cannot find the global maximum power point (GMPP). To solve such problem, a global maximum power point tracking method (GMPPT) is improved, combined with traditional MPPT method and particle swarm optimization (PSO) algorithm. Under different operating conditions of PV cells, different tracking algorithms are used. When the environment changes, the improved PSO algorithm is adopted to realize the global optimal search, and the variable step incremental conductance (INC) method is adopted to achieve MPPT in optimal local location. Based on the simulation model of the PV grid system built in Matlab/Simulink, comparative analysis of the tracking effect of MPPT by the proposed control algorithm and the traditional MPPT method under the uniform solar condition and PSC, validate the correctness, feasibility and effectiveness of the proposed control strategy.

The effect of a novel photodynamic activation method mediated by curcumin on oyster shelf life and quality.

PubMed

Liu, Fang; Li, Zhaojie; Cao, Binbin; Wu, Juan; Wang, Yuming; Xue, Yong; Xu, Jie; Xue, Changhu; Tang, Qing Juan

2016-09-01

In this paper, the effect of photodynamic method mediated by curcumin (PDT) on the shelf life and quality of pacific oysters during storage at 5±1°C were analyzed. In our previous study we investigated the optimal treatment conditions of photodynamic method mediated by curcumin to sterilization were 10uM photosensitizer concentration and 5.4J/cm 2 light energy density. Under these conditions, the effect of a novel photodynamic activation method mediated by curcumin on oyster shelf life and quality was researched. The total bacterial counts, TVB-N content and sensory analysis were used to evaluate the effects on oyster shelf life. The oyster shelf life was prolonged from 8days to 12days after photodynamic treatment and the oysters in the treatment group displayed notable odor retention, produced fewer odor corrupting substances when the control group oysters reached the end of their shelf life (day 8). Texture, free amino acid contents and fatty acid levels were applied to estimate the quality of the treated oysters. The texture had no significant change after treated with PDT. At the end of oyster shelf life, compared PDT group (PDT) with control group (control), total free amino acid contents (control: 234.30mg/100g, PDT: 813.02mg/100g) was higher and free fatty acid levels (control: 0.071mEq/L, PDT: 0.0455mEq/L) displayed lower in PDT group. This indicated that the treated oysters oxidized minimally, decayed slowly, decomposed fewer nutrients and had lower metabolic levels of spoilage microorganisms. PDT has a positive effect on prolonging oyster shelf life and its quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

Data-Driven Zero-Sum Neuro-Optimal Control for a Class of Continuous-Time Unknown Nonlinear Systems With Disturbance Using ADP.

PubMed

Wei, Qinglai; Song, Ruizhuo; Yan, Pengfei

2016-02-01

This paper is concerned with a new data-driven zero-sum neuro-optimal control problem for continuous-time unknown nonlinear systems with disturbance. According to the input-output data of the nonlinear system, an effective recurrent neural network is introduced to reconstruct the dynamics of the nonlinear system. Considering the system disturbance as a control input, a two-player zero-sum optimal control problem is established. Adaptive dynamic programming (ADP) is developed to obtain the optimal control under the worst case of the disturbance. Three single-layer neural networks, including one critic and two action networks, are employed to approximate the performance index function, the optimal control law, and the disturbance, respectively, for facilitating the implementation of the ADP method. Convergence properties of the ADP method are developed to show that the system state will converge to a finite neighborhood of the equilibrium. The weight matrices of the critic and the two action networks are also convergent to finite neighborhoods of their optimal ones. Finally, the simulation results will show the effectiveness of the developed data-driven ADP methods.

A panning DLT procedure for three-dimensional videography.

PubMed

Yu, B; Koh, T J; Hay, J G

1993-06-01

The direct linear transformation (DLT) method [Abdel-Aziz and Karara, APS Symposium on Photogrammetry. American Society of Photogrammetry, Falls Church, VA (1971)] is widely used in biomechanics to obtain three-dimensional space coordinates from film and video records. This method has some major shortcomings when used to analyze events which take place over large areas. To overcome these shortcomings, a three-dimensional data collection method based on the DLT method, and making use of panning cameras, was developed. Several small single control volumes were combined to construct a large total control volume. For each single control volume, a regression equation (calibration equation) is developed to express each of the 11 DLT parameters as a function of camera orientation, so that the DLT parameters can then be estimated from arbitrary camera orientations. Once the DLT parameters are known for at least two cameras, and the associated two-dimensional film or video coordinates of the event are obtained, the desired three-dimensional space coordinates can be computed. In a laboratory test, five single control volumes (in a total control volume of 24.40 x 2.44 x 2.44 m3) were used to test the effect of the position of the single control volume on the accuracy of the computed three dimensional space coordinates. Linear and quadratic calibration equations were used to test the effect of the order of the equation on the accuracy of the computed three dimensional space coordinates. For four of the five single control volumes tested, the mean resultant errors associated with the use of the linear calibration equation were significantly larger than those associated with the use of the quadratic calibration equation. The position of the single control volume had no significant effect on the mean resultant errors in computed three dimensional coordinates when the quadratic calibration equation was used. Under the same data collection conditions, the mean resultant errors in the computed three dimensional coordinates associated with the panning and stationary DLT methods were 17 and 22 mm, respectively. The major advantages of the panning DLT method lie in the large image sizes obtained and in the ease with which the data can be collected. The method also has potential for use in a wide variety of contexts. The major shortcoming of the method is the large amount of digitizing necessary to calibrate the total control volume. Adaptations of the method to reduce the amount of digitizing required are being explored.

[Various methods of overcoming resistance to therapy in childhood and adolescent schizophrenia].

PubMed

Antropov, Iu F

1981-01-01

Under examination there were 64 schizophrenic children and adolescents resistant to psychopharmacotherapy. For overcoming the resistance a method of sudden cancellation of the psychotropic drugs (as well as some of its modifications, such as, combinations with sulfozine and diuretics) was used. The control group consisted of 32 patients in whom the psychopharmacotherapy was not interrupted. As a result of using the sudden cancellation method and its modifications a marked therapeutic effect (remissions of the types "B" and "C") was obtained in 36 patients out of the 64. This effect was the most pronounced in 18 patients (out of 22) with depressive-delusional states. The effectiveness of the method used was confirmed by comparison with the control patients. At the same time the "cancellation syndrome" that developed after the therapy interruption was less pronounced and lasting than in adult patients.

A New Method for Partial Correction of Residual Confounding in Time-Series and Other Observational Studies.

PubMed

Flanders, W Dana; Strickland, Matthew J; Klein, Mitchel

2017-05-15

Methods exist to detect residual confounding in epidemiologic studies. One requires a negative control exposure with 2 key properties: 1) conditional independence of the negative control and the outcome (given modeled variables) absent confounding and other model misspecification, and 2) associations of the negative control with uncontrolled confounders and the outcome. We present a new method to partially correct for residual confounding: When confounding is present and our assumptions hold, we argue that estimators from models that include a negative control exposure with these 2 properties tend to be less biased than those from models without it. Using regression theory, we provide theoretical arguments that support our claims. In simulations, we empirically evaluated the approach using a time-series study of ozone effects on asthma emergency department visits. In simulations, effect estimators from models that included the negative control exposure (ozone concentrations 1 day after the emergency department visit) had slightly or modestly less residual confounding than those from models without it. Theory and simulations show that including the negative control can reduce residual confounding, if our assumptions hold. Our method differs from available methods because it uses a regression approach involving an exposure-based indicator rather than a negative control outcome to partially correct for confounding. © The Author 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A multilevel control system for the large space telescope. [numerical analysis/optimal control

NASA Technical Reports Server (NTRS)

Siljak, D. D.; Sundareshan, S. K.; Vukcevic, M. B.

1975-01-01

A multilevel scheme was proposed for control of Large Space Telescope (LST) modeled by a three-axis-six-order nonlinear equation. Local controllers were used on the subsystem level to stabilize motions corresponding to the three axes. Global controllers were applied to reduce (and sometimes nullify) the interactions among the subsystems. A multilevel optimization method was developed whereby local quadratic optimizations were performed on the subsystem level, and global control was again used to reduce (nullify) the effect of interactions. The multilevel stabilization and optimization methods are presented as general tools for design and then used in the design of the LST Control System. The methods are entirely computerized, so that they can accommodate higher order LST models with both conceptual and numerical advantages over standard straightforward design techniques.

Application of Nonlinear Systems Inverses to Automatic Flight Control Design: System Concepts and Flight Evaluations

NASA Technical Reports Server (NTRS)

Meyer, G.; Cicolani, L.

1981-01-01

A practical method for the design of automatic flight control systems for aircraft with complex characteristics and operational requirements, such as the powered lift STOL and V/STOL configurations, is presented. The method is effective for a large class of dynamic systems requiring multi-axis control which have highly coupled nonlinearities, redundant controls, and complex multidimensional operational envelopes. It exploits the concept of inverse dynamic systems, and an algorithm for the construction of inverse is given. A hierarchic structure for the total control logic with inverses is presented. The method is illustrated with an application to the Augmentor Wing Jet STOL Research Aircraft equipped with a digital flight control system. Results of flight evaluation of the control concept on this aircraft are presented.

Terminal Sliding Mode-Based Consensus Tracking Control for Networked Uncertain Mechanical Systems on Digraphs.

PubMed

Chen, Gang; Song, Yongduan; Guan, Yanfeng

2018-03-01

This brief investigates the finite-time consensus tracking control problem for networked uncertain mechanical systems on digraphs. A new terminal sliding-mode-based cooperative control scheme is developed to guarantee that the tracking errors converge to an arbitrarily small bound around zero in finite time. All the networked systems can have different dynamics and all the dynamics are unknown. A neural network is used at each node to approximate the local unknown dynamics. The control schemes are implemented in a fully distributed manner. The proposed control method eliminates some limitations in the existing terminal sliding-mode-based consensus control methods and extends the existing analysis methods to the case of directed graphs. Simulation results on networked robot manipulators are provided to show the effectiveness of the proposed control algorithms.

Field Evaluation of Fracture Control in Tunnel Blasting

DOT National Transportation Integrated Search

1979-12-01

The objective of this research was to implement fracture control procedures in a tunnel project and to assess the practicality, advantages, disadvantages, performance and cost effectiveness of fracture control methods against smooth blasting procedur...

Effects of structural nonlinearity on subsonic aeroelastic characteristics of an aircraft wing with control surface

NASA Astrophysics Data System (ADS)

Bae, J.-S.; Inman, D. J.; Lee, I.

2004-07-01

The nonlinear aeroelastic characteristics of an aircraft wing with a control surface are investigated. A doublet-hybrid method is used for the calculation of subsonic unsteady aerodynamic forces and the minimum-state approximation is used for the approximation of aerodynamic forces. A free vibration analysis is performed using the finite element and the fictitious mass methods. The structural nonlinearity in the control surface hinge is represented by both free-play and a bilinear nonlinearity. These nonlinearities are linearized using the describing function method. From the nonlinear flutter analysis, various types of limit cycle oscillations and periodic motions are observed in a wide range of air speeds below the linear flutter boundary. The effects of structural nonlinearities on aeroelastic characteristics are investigated.

Development of a fuel cell plug-in hybrid electric vehicle and vehicle simulator for energy management assessment

NASA Astrophysics Data System (ADS)

Meintz, Andrew Lee

This dissertation offers a description of the development of a fuel cell plug-in hybrid electric vehicle focusing on the propulsion architecture selection, propulsion system control, and high-level energy management. Two energy management techniques have been developed and implemented for real-time control of the vehicle. The first method is a heuristic method that relies on a short-term moving average of the vehicle power requirements. The second method utilizes an affine function of the short-term and long-term moving average vehicle power requirements. The development process of these methods has required the creation of a vehicle simulator capable of estimating the effect of changes to the energy management control techniques on the overall vehicle energy efficiency. Furthermore, the simulator has allowed for the refinement of the energy management methods and for the stability of the method to be analyzed prior to on-road testing. This simulator has been verified through on-road testing of a constructed prototype vehicle under both highway and city driving schedules for each energy management method. The results of the finalized vehicle control strategies are compared with the simulator predictions and an assessment of the effectiveness of both strategies is discussed. The methods have been evaluated for energy consumption in the form of both hydrogen fuel and stored electricity from grid charging.

Different methods to analyze stepped wedge trial designs revealed different aspects of intervention effects.

PubMed

Twisk, J W R; Hoogendijk, E O; Zwijsen, S A; de Boer, M R

2016-04-01

Within epidemiology, a stepped wedge trial design (i.e., a one-way crossover trial in which several arms start the intervention at different time points) is increasingly popular as an alternative to a classical cluster randomized controlled trial. Despite this increasing popularity, there is a huge variation in the methods used to analyze data from a stepped wedge trial design. Four linear mixed models were used to analyze data from a stepped wedge trial design on two example data sets. The four methods were chosen because they have been (frequently) used in practice. Method 1 compares all the intervention measurements with the control measurements. Method 2 treats the intervention variable as a time-independent categorical variable comparing the different arms with each other. In method 3, the intervention variable is a time-dependent categorical variable comparing groups with different number of intervention measurements, whereas in method 4, the changes in the outcome variable between subsequent measurements are analyzed. Regarding the results in the first example data set, methods 1 and 3 showed a strong positive intervention effect, which disappeared after adjusting for time. Method 2 showed an inverse intervention effect, whereas method 4 did not show a significant effect at all. In the second example data set, the results were the opposite. Both methods 2 and 4 showed significant intervention effects, whereas the other two methods did not. For method 4, the intervention effect attenuated after adjustment for time. Different methods to analyze data from a stepped wedge trial design reveal different aspects of a possible intervention effect. The choice of a method partly depends on the type of the intervention and the possible time-dependent effect of the intervention. Furthermore, it is advised to combine the results of the different methods to obtain an interpretable overall result. Copyright © 2016 Elsevier Inc. All rights reserved.

An Implementation Method of the Fractional-Order PID Control System Considering the Memory Constraint and its Application to the Temperature Control of Heat Plate

NASA Astrophysics Data System (ADS)

Sasano, Koji; Okajima, Hiroshi; Matsunaga, Nobutomo

Recently, the fractional order PID (FO-PID) control, which is the extension of the PID control, has been focused on. Even though the FO-PID requires the high-order filter, it is difficult to realize the high-order filter due to the memory limitation of digital computer. For implementation of FO-PID, approximation of the fractional integrator and differentiator are required. Short memory principle (SMP) is one of the effective approximation methods. However, there is a disadvantage that the approximated filter with SMP cannot eliminate the steady-state error. For this problem, we introduce the distributed implementation of the integrator and the dynamic quantizer to make the efficient use of permissible memory. The objective of this study is to clarify how to implement the accurate FO-PID with limited memories. In this paper, we propose the implementation method of FO-PID with memory constraint using dynamic quantizer. And the trade off between approximation of fractional elements and quantized data size are examined so as to close to the ideal FO-PID responses. The effectiveness of proposed method is evaluated by numerical example and experiment in the temperature control of heat plate.

An Evaluation of the Effectiveness of a Computer-Assisted Reading Intervention

ERIC Educational Resources Information Center

Messer, David; Nash, Gilly

2018-01-01

Background: A cost-effective method to address reading delays is to use computer-assisted learning, but these techniques are not always effective. Methods: We evaluated a commercially available computer system that uses visual mnemonics, in a randomised controlled trial with 78 English-speaking children (mean age 7 years) who their schools…

The Co-simulation of Humanoid Robot Based on Solidworks, ADAMS and Simulink

NASA Astrophysics Data System (ADS)

Song, Dalei; Zheng, Lidan; Wang, Li; Qi, Weiwei; Li, Yanli

A simulation method of adaptive controller is proposed for the humanoid robot system based on co-simulation of Solidworks, ADAMS and Simulink. A complex mathematical modeling process is avoided by this method, and the real time dynamic simulating function of Simulink would be exerted adequately. This method could be generalized to other complicated control system. This method is adopted to build and analyse the model of humanoid robot. The trajectory tracking and adaptive controller design also proceed based on it. The effect of trajectory tracking is evaluated by fitting-curve theory of least squares method. The anti-interference capability of the robot is improved a lot through comparative analysis.

Control of Respiratory Motion by Hypnosis Intervention during Radiotherapy of Lung Cancer I

PubMed Central

Deng, Jie; Xie, Yaoqin

2013-01-01

The uncertain position of lung tumor during radiotherapy compromises the treatment effect. To effectively control respiratory motion during radiotherapy of lung cancer without any side effects, a novel control scheme, hypnosis, has been introduced in lung cancer treatment. In order to verify the suggested method, six volunteers were selected with a wide range of distribution of age, weight, and chest circumference. A set of experiments have been conducted for each volunteer, under the guidance of the professional hypnotist. All the experiments were repeated in the same environmental condition. The amplitude of respiration has been recorded under the normal state and hypnosis, respectively. Experimental results show that the respiration motion of volunteers in hypnosis has smaller and more stable amplitudes than in normal state. That implies that the hypnosis intervention can be an alternative way for respiratory control, which can effectively reduce the respiratory amplitude and increase the stability of respiratory cycle. The proposed method will find useful application in image-guided radiotherapy. PMID:24093100

Size-controlled fabrication of zein nano/microparticles by modified anti-solvent precipitation with/without sodium caseinate

PubMed Central

Li, Feng; Chen, Yan; Liu, Shubo; Qi, Jian; Wang, Weiying; Wang, Chenhua; Zhong, Ruiyue; Chen, Zhijun; Li, Xiaoming; Guan, Yuanzhou; Kong, Wei; Zhang, Yong

2017-01-01

Zein-based nano/microparticles have been demonstrated to be promising carrier systems for both the food industry and biomedical applications. However, the fabrication of size-controlled zein particles has been a challenging issue. In this study, a modified anti-solvent precipitation method was developed, and the effects of various factors, such as mixing method, solvent/anti-solvent ratio, temperature, zein concentrations and the presence of sodium caseinate (SC) on properties of zein particles were investigated. Evidence is presented that, among the previously mentioned factors, the mixing method, especially mixing rate, could be used as an effective parameter to control the size of zein particles without changing other parameters. Moreover, through fine-tuning the mixing rate together with zein concentration, particles with sizes ranging from nanometers to micrometers and low polydispersity index values could be easily obtained. Based on the size-controlled fabrication method, SC-coated zein nanoparticles could also be obtained in a size-controlled manner by incubation of the coating material with the already-formed zein particles. The resultant nanoparticles showed better performance in both drug loading and controlled release, compared with zein/SC hybrid nanoparticles fabricated by adding aqueous ethanol solution to SC solution. The possible mechanisms of the nanoprecipitation process and self-assembly formation of these nanoparticles are discussed. PMID:29184408

Size-controlled fabrication of zein nano/microparticles by modified anti-solvent precipitation with/without sodium caseinate.

PubMed

Li, Feng; Chen, Yan; Liu, Shubo; Qi, Jian; Wang, Weiying; Wang, Chenhua; Zhong, Ruiyue; Chen, Zhijun; Li, Xiaoming; Guan, Yuanzhou; Kong, Wei; Zhang, Yong

2017-01-01

Zein-based nano/microparticles have been demonstrated to be promising carrier systems for both the food industry and biomedical applications. However, the fabrication of size-controlled zein particles has been a challenging issue. In this study, a modified anti-solvent precipitation method was developed, and the effects of various factors, such as mixing method, solvent/anti-solvent ratio, temperature, zein concentrations and the presence of sodium caseinate (SC) on properties of zein particles were investigated. Evidence is presented that, among the previously mentioned factors, the mixing method, especially mixing rate, could be used as an effective parameter to control the size of zein particles without changing other parameters. Moreover, through fine-tuning the mixing rate together with zein concentration, particles with sizes ranging from nanometers to micrometers and low polydispersity index values could be easily obtained. Based on the size-controlled fabrication method, SC-coated zein nanoparticles could also be obtained in a size-controlled manner by incubation of the coating material with the already-formed zein particles. The resultant nanoparticles showed better performance in both drug loading and controlled release, compared with zein/SC hybrid nanoparticles fabricated by adding aqueous ethanol solution to SC solution. The possible mechanisms of the nanoprecipitation process and self-assembly formation of these nanoparticles are discussed.

A dynamic access control method based on QoS requirement

NASA Astrophysics Data System (ADS)

Li, Chunquan; Wang, Yanwei; Yang, Baoye; Hu, Chunyang

2013-03-01

A dynamic access control method is put forward to ensure the security of the sharing service in Cloud Manufacturing, according to the application characteristics of cloud manufacturing collaborative task. The role-based access control (RBAC) model is extended according to the characteristics of cloud manufacturing in this method. The constraints are considered, which are from QoS requirement of the task context to access control, based on the traditional static authorization. The fuzzy policy rules are established about the weighted interval value of permissions. The access control authorities of executable service by users are dynamically adjusted through the fuzzy reasoning based on the QoS requirement of task. The main elements of the model are described. The fuzzy reasoning algorithm of weighted interval value based QoS requirement is studied. An effective method is provided to resolve the access control of cloud manufacturing.

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.

Synthesis of aircraft structures using integrated design and analysis methods

NASA Technical Reports Server (NTRS)

Sobieszczanski-Sobieski, J.; Goetz, R. C.

1978-01-01

A systematic research is reported to develop and validate methods for structural sizing of an airframe designed with the use of composite materials and active controls. This research program includes procedures for computing aeroelastic loads, static and dynamic aeroelasticity, analysis and synthesis of active controls, and optimization techniques. Development of the methods is concerned with the most effective ways of integrating and sequencing the procedures in order to generate structural sizing and the associated active control system, which is optimal with respect to a given merit function constrained by strength and aeroelasticity requirements.

Method and apparatus for controlling cross contamination of microfluid channels

DOEpatents

Hasselbrink, Jr., Ernest F.; Rehm, Jason E [Alameda, CA; Paul, Phillip H [Livermore, CA; Arnold, Don W [Livermore, CA

2006-02-07

A method for controlling fluid flow at junctions in microchannel systems. Control of fluid flow is accomplished generally by providing increased resistance to electric-field and pressure-driven flow in the form of regions of reduced effective cross-sectional area within the microchannels and proximate a channel junction. By controlling these flows in the region of a microchannel junction it is possible to eliminate sample dispersion and cross contamination and inject well-defined volumes of fluid from one channel to another.

Apparatus and method to inject a reductant into an exhaust gas feedstream

DOEpatents

Viola, Michael B [Macomb Township, MI

2009-09-22

An exhaust aftertreatment system for an internal combustion engine is provided including an apparatus and method to inject a reductant into the exhaust gas feedstream. Included is a fuel metering device adapted to inject reductant into the exhaust gas feedstream and a controllable pressure regulating device. A control module is operatively connected to the reductant metering device and the controllable pressure regulating device, and, adapted to effect flow of reductant into the exhaust gas feedstream over a controllable flow range.

Power Source Status Estimation and Drive Control Method for Autonomous Decentralized Hybrid Train

NASA Astrophysics Data System (ADS)

Furuya, Takemasa; Ogawa, Kenichi; Yamamoto, Takamitsu; Hasegawa, Hitoshi

A hybrid control system has two main functions: power sharing and equipment protection. In this paper, we discuss the design, construction and testing of a drive control method for an autonomous decentralized hybrid train with 100-kW-class fuel cells (FC) and 36-kWh lithium-ion batteries (Li-Batt). The main objectives of this study are to identify the operation status of the power sources on the basis of the input voltage of the traction inverter and to estimate the maximum traction power control basis of the power-source status. The proposed control method is useful in preventing overload operation of the onboard power sources in an autonomous decentralized hybrid system that has a flexible main circuit configuration and a few control signal lines. Further, with this method, the initial cost of a hybrid system can be reduced and the retrofit design of the hybrid system can be simplified. The effectiveness of the proposed method is experimentally confirmed by using a real-scale hybrid train system.

Tree hazard control on recreation sites...estimating local budgets

Treesearch

Lee A. Paine

1967-01-01

Tree hazard control efforts on recreation sites are subject to budget and administrative restrictions. To make the most effective use of available control funds, priorities should be assigned to various classes of tree defects and a budget set up. With the method provided, local priorities are based on cost effectiveness. Some guide lines and a worksheet for planning a...

A Cluster Randomized Controlled Trial Testing the Effectiveness of Houvast: A Strengths-Based Intervention for Homeless Young Adults

ERIC Educational Resources Information Center

Krabbenborg, Manon A. M.; Boersma, Sandra N.; van der Veld, William M.; van Hulst, Bente; Vollebergh, Wilma A. M.; Wolf, Judith R. L. M.

2017-01-01

Objective: To test the effectiveness of Houvast: a strengths-based intervention for homeless young adults. Method: A cluster randomized controlled trial was conducted with 10 Dutch shelter facilities randomly allocated to an intervention and a control group. Homeless young adults were interviewed when entering the facility and when care ended.…

Effects of foot massage applied in two different methods on symptom control in colorectal cancer patients: Randomised control trial.

PubMed

Uysal, Neşe; Kutlutürkan, Sevinç; Uğur, Işıl

2017-06-01

This randomized controlled clinical study aimed to determine the effect of 2 foot massage methods on symptom control in people with colorectal cancer who received chemoradiotherapy. Data were collected between June 16, 2015, and February 10, 2016, in the Department of Radiation Oncology of an oncology training and research hospital. The sample comprised 60 participants. Data were collected using an introductory information form, common terminology criteria for adverse events and European Organization for Research and Treatment of Cancer Quality of Life Questionnaires C30 and CR29. Participants were randomly allocated to 3 groups: classical foot massage, reflexology, and standard care control. The classical massage group received foot massage using classical massage techniques, and the reflexology group received foot reflexology focusing on symptom-oriented reflexes twice a week during a 5-week chemoradiotherapy treatment schedule. The control group received neither classical massage nor reflexology. All patients were provided with the same clinic routine care. The classical massage was effective in reducing pain level and distension incidence while foot reflexology was effective in reducing pain and fatigue level, lowering incidence of distension and urinary frequency and improving life quality. © 2017 John Wiley & Sons Australia, Ltd.

Design, analysis, and interpretation of field quality-control data for water-sampling projects

USGS Publications Warehouse

Mueller, David K.; Schertz, Terry L.; Martin, Jeffrey D.; Sandstrom, Mark W.

2015-01-01

The report provides extensive information about statistical methods used to analyze quality-control data in order to estimate potential bias and variability in environmental data. These methods include construction of confidence intervals on various statistical measures, such as the mean, percentiles and percentages, and standard deviation. The methods are used to compare quality-control results with the larger set of environmental data in order to determine whether the effects of bias and variability might interfere with interpretation of these data. Examples from published reports are presented to illustrate how the methods are applied, how bias and variability are reported, and how the interpretation of environmental data can be qualified based on the quality-control analysis.

Effect of Two Different Methods of Initiating Atomoxetine on the Adverse Event Profile of Atomoxetine

ERIC Educational Resources Information Center

Greenhill, Laurence L.; Newcorn, Jeffrey H.; Gao, Haitao; Feldman, Peter D.

2007-01-01

Objective: To compare the effects of two different methods for initiating atomoxetine in terms of the incidence of early adverse events. Method: Data on atomoxetine treatment-emergent adverse events in youths, ages 6 to 18 years, were analyzed from five randomized, double-blind, placebo-controlled, acute-phase studies. Two studies involve…

Rotor Position Sensorless Control and Its Parameter Sensitivity of Permanent Magnet Motor Based on Model Reference Adaptive System

NASA Astrophysics Data System (ADS)

Ohara, Masaki; Noguchi, Toshihiko

This paper describes a new method for a rotor position sensorless control of a surface permanent magnet synchronous motor based on a model reference adaptive system (MRAS). This method features the MRAS in a current control loop to estimate a rotor speed and position by using only current sensors. This method as well as almost all the conventional methods incorporates a mathematical model of the motor, which consists of parameters such as winding resistances, inductances, and an induced voltage constant. Hence, the important thing is to investigate how the deviation of these parameters affects the estimated rotor position. First, this paper proposes a structure of the sensorless control applied in the current control loop. Next, it proves the stability of the proposed method when motor parameters deviate from the nominal values, and derives the relationship between the estimated position and the deviation of the parameters in a steady state. Finally, some experimental results are presented to show performance and effectiveness of the proposed method.

Effects of time-shifted data on flight determined stability and control derivatives

NASA Technical Reports Server (NTRS)

Steers, S. T.; Iliff, K. W.

1975-01-01

Flight data were shifted in time by various increments to assess the effects of time shifts on estimates of stability and control derivatives produced by a maximum likelihood estimation method. Derivatives could be extracted from flight data with the maximum likelihood estimation method even if there was a considerable time shift in the data. Time shifts degraded the estimates of the derivatives, but the degradation was in a consistent rather than a random pattern. Time shifts in the control variables caused the most degradation, and the lateral-directional rotary derivatives were affected the most by time shifts in any variable.

Can Land Managers Control Japanese Knotweed? Lessons from Control Tests in Belgium

NASA Astrophysics Data System (ADS)

Delbart, Emmanuel; Mahy, Grégory; Weickmans, Bernard; Henriet, François; Crémer, Sébastien; Pieret, Nora; Vanderhoeven, Sonia; Monty, Arnaud

2012-12-01

Japanese knotweed Fallopia japonica is an extremely abundant invasive plant in Belgium and surrounding countries. To date, no eradication method is available for land managers facing the invasion of this rhizomatous plant. We tested different chemical herbicides with two application methods (spraying and stem injection), as well as mechanical treatments, on knotweed clones throughout southern Belgium. The tested control methods were selected to be potentially usable by managers, e.g., using legally accepted rates for herbicides. Stem volume, height and density reduction were assessed after one or two years, depending on the control method. Labor estimations were made for each control method. No tested control method completely eradicated the clones. Stem injection with glyphosate-based herbicide (3.6 kg ha-1 of acid equivalent glyphosate) caused the most damage, i.e., no sprouting shoots were observed the year following the injection. The following year, though, stunted shoots appeared. Among the mechanical control methods, repeated cuts combined with native tree transplanting most appreciably reduced knotweed development. The most efficient methods we tested could curb knotweed invasion, but are not likely to be effective in eradicating the species. As such, they should be included in a more integrated restoration strategy, together with prevention and public awareness campaigns.

Epidemiologic methods in clinical trials.

PubMed

Rothman, K J

1977-04-01

Epidemiologic methods developed to control confounding in non-experimental studies are equally applicable for experiments. In experiments, most confounding is usually controlled by random allocation of subjects to treatment groups, but randomization does not preclude confounding except for extremely large studies, the degree of confounding expected being inversely related to the size of the treatment groups. In experiments, as in non-experimental studies, the extent of confounding for each risk indicator should be assessed, and if sufficiently large, controlled. Confounding is properly assessed by comparing the unconfounded effect estimate to the crude effect estimate; a common error is to assess confounding by statistical tests of significance. Assessment of confounding involves its control as a prerequisite. Control is most readily and cogently achieved by stratification of the data, though with many factors to control simultaneously, multivariate analysis or a combination of multivariate analysis and stratification might be necessary.

Composite fuzzy sliding mode control of nonlinear singularly perturbed systems.

PubMed

Nagarale, Ravindrakumar M; Patre, B M

2014-05-01

This paper deals with the robust asymptotic stabilization for a class of nonlinear singularly perturbed systems using the fuzzy sliding mode control technique. In the proposed approach the original system is decomposed into two subsystems as slow and fast models by the singularly perturbed method. The composite fuzzy sliding mode controller is designed for stabilizing the full order system by combining separately designed slow and fast fuzzy sliding mode controllers. The two-time scale design approach minimizes the effect of boundary layer system on the full order system. A stability analysis allows us to provide sufficient conditions for the asymptotic stability of the full order closed-loop system. The simulation results show improved system performance of the proposed controller as compared to existing methods. The experimentation results validate the effectiveness of the proposed controller. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Interventions to Improve Medication Adherence among Older Adults: Meta-Analysis of Adherence Outcomes among Randomized Controlled Trials

ERIC Educational Resources Information Center

Conn, Vicki S.; Hafdahl, Adam R.; Cooper, Pamela S.; Ruppar, Todd M.; Mehr, David R.; Russell, Cynthia L.

2009-01-01

Purpose: This study investigated the effectiveness of interventions to improve medication adherence (MA) in older adults. Design and Methods: Meta-analysis was used to synthesize results of 33 published and unpublished randomized controlled trials. Random-effects models were used to estimate overall mean effect sizes (ESs) for MA, knowledge,…

What can formal methods offer to digital flight control systems design

NASA Technical Reports Server (NTRS)

Good, Donald I.

1990-01-01

Formal methods research begins to produce methods which will enable mathematic modeling of the physical behavior of digital hardware and software systems. The development of these methods directly supports the NASA mission of increasing the scope and effectiveness of flight system modeling capabilities. The conventional, continuous mathematics that is used extensively in modeling flight systems is not adequate for accurate modeling of digital systems. Therefore, the current practice of digital flight control system design has not had the benefits of extensive mathematical modeling which are common in other parts of flight system engineering. Formal methods research shows that by using discrete mathematics, very accurate modeling of digital systems is possible. These discrete modeling methods will bring the traditional benefits of modeling to digital hardware and hardware design. Sound reasoning about accurate mathematical models of flight control systems can be an important part of reducing risk of unsafe flight control.

Controlling Type I Error Rates in Assessing DIF for Logistic Regression Method Combined with SIBTEST Regression Correction Procedure and DIF-Free-Then-DIF Strategy

ERIC Educational Resources Information Center

Shih, Ching-Lin; Liu, Tien-Hsiang; Wang, Wen-Chung

2014-01-01

The simultaneous item bias test (SIBTEST) method regression procedure and the differential item functioning (DIF)-free-then-DIF strategy are applied to the logistic regression (LR) method simultaneously in this study. These procedures are used to adjust the effects of matching true score on observed score and to better control the Type I error…

The Manufacture, Shipping and Receiving and Quality Control of Rodent Bedding Materials

NASA Technical Reports Server (NTRS)

Kraft, Lisbeth M.

1980-01-01

The criteria for rodent bedding and nesting materials are discussed. The literature is reviewed regarding sources of bedding materials, manufacturing methods, quality control, procedures (microbiological, physical and chemical), storage, methods, shipment, methods of use and disposal, current knowledge concerning bedding effects on animals as related to research and testing and legal aspects. Future needs, especially with respect to the promulgation of standards, also are addressed.

Biologically Based Methods for Control of Fumonisin-Producing Fusarium Species and Reduction of the Fumonisins.

PubMed

Alberts, Johanna F; van Zyl, Willem H; Gelderblom, Wentzel C A

2016-01-01

Infection by the fumonisin-producing Fusarium spp. and subsequent fumonisin contamination of maize adversely affect international trade and economy with deleterious effects on human and animal health. In developed countries high standards of the major food suppliers and retailers are upheld and regulatory controls deter the importation and local marketing of fumonisin-contaminated food products. In developing countries regulatory measures are either lacking or poorly enforced, due to food insecurity, resulting in an increased mycotoxin exposure. The lack and poor accessibility of effective and environmentally safe control methods have led to an increased interest in practical and biological alternatives to reduce fumonisin intake. These include the application of natural resources, including plants, microbial cultures, genetic material thereof, or clay minerals pre- and post-harvest. Pre-harvest approaches include breeding for resistant maize cultivars, introduction of biocontrol microorganisms, application of phenolic plant extracts, and expression of antifungal proteins and fumonisin degrading enzymes in transgenic maize cultivars. Post-harvest approaches include the removal of fumonisins by natural clay adsorbents and enzymatic degradation of fumonisins through decarboxylation and deamination by recombinant carboxylesterase and aminotransferase enzymes. Although, the knowledge base on biological control methods has expanded, only a limited number of authorized decontamination products and methods are commercially available. As many studies detailed the use of natural compounds in vitro, concepts in reducing fumonisin contamination should be developed further for application in planta and in the field pre-harvest, post-harvest, and during storage and food-processing. In developed countries an integrated approach, involving good agricultural management practices, hazard analysis and critical control point (HACCP) production, and storage management, together with selected biologically based treatments, mild chemical and physical treatments could reduce fumonisin contamination effectively. In rural subsistence farming communities, simple, practical, and culturally acceptable hand-sorting, maize kernel washing, and dehulling intervention methods proved to be effective as a last line of defense for reducing fumonisin exposure. Biologically based methods for control of fumonisin-producing Fusarium spp. and decontamination of the fumonisins could have potential commercial application, while simple and practical intervention strategies could also impact positively on food safety and security, especially in rural populations reliant on maize as a dietary staple.

Rigorous control conditions diminish treatment effects in weight loss randomized controlled trials

PubMed Central

Dawson, John A.; Kaiser, Kathryn A.; Affuso, Olivia; Cutter, Gary R.; Allison, David B.

2015-01-01

Background It has not been established whether control conditions with large weight losses (WLs) diminish expected treatment effects in WL or prevention of weight gain (PWG) randomized controlled trials (RCTs). Subjects/Methods We performed a meta-analysis of 239 WL/PWG RCTs that include a control group and at least one treatment group. A maximum likelihood meta-analysis framework is used in order to model and understand the relationship between treatment effects and control group outcomes. Results Under the informed model, an increase in control group WL of one kilogram corresponds with an expected shrinkage of the treatment effect by 0.309 kg [95% CI (−0.480, −0.138), p = 0.00081]; this result is robust against violations of the model assumptions. Conclusions We find that control conditions with large weight losses diminish expected treatment effects. Our investigation may be helpful to clinicians as they design future WL/PWG studies. PMID:26449419

Magnetic agglomeration method for size control in the synthesis of magnetic nanoparticles

DOEpatents

Huber, Dale L [Albuquerque, NM

2011-07-05

A method for controlling the size of chemically synthesized magnetic nanoparticles that employs magnetic interaction between particles to control particle size and does not rely on conventional kinetic control of the reaction to control particle size. The particles are caused to reversibly agglomerate and precipitate from solution; the size at which this occurs can be well controlled to provide a very narrow particle size distribution. The size of particles is controllable by the size of the surfactant employed in the process; controlling the size of the surfactant allows magnetic control of the agglomeration and precipitation processes. Agglomeration is used to effectively stop particle growth to provide a very narrow range of particle sizes.

Probabilistic Parameter Uncertainty Analysis of Single Input Single Output Control Systems

NASA Technical Reports Server (NTRS)

Smith, Brett A.; Kenny, Sean P.; Crespo, Luis G.

2005-01-01

The current standards for handling uncertainty in control systems use interval bounds for definition of the uncertain parameters. This approach gives no information about the likelihood of system performance, but simply gives the response bounds. When used in design, current methods of m-analysis and can lead to overly conservative controller design. With these methods, worst case conditions are weighted equally with the most likely conditions. This research explores a unique approach for probabilistic analysis of control systems. Current reliability methods are examined showing the strong areas of each in handling probability. A hybrid method is developed using these reliability tools for efficiently propagating probabilistic uncertainty through classical control analysis problems. The method developed is applied to classical response analysis as well as analysis methods that explore the effects of the uncertain parameters on stability and performance metrics. The benefits of using this hybrid approach for calculating the mean and variance of responses cumulative distribution functions are shown. Results of the probabilistic analysis of a missile pitch control system, and a non-collocated mass spring system, show the added information provided by this hybrid analysis.

Diversification of crested wheatgrass stands in Utah

Treesearch

April Hulet

2009-01-01

Agropyron cristatum [L.] Gaertner (crested wheatgrass) continues to be seeded on burned wildlands. Effective control methods need to be developed to convert these seedings to more diverse native plant communities. This research was designed to determine effective ways to control A. cristatum and establish native species while...

Can We Control Cheating in the Classroom?

ERIC Educational Resources Information Center

Kerkvliet, Joe; Sigmund, Charles L.

1999-01-01

Examines the determinants of class-specific academic cheating on examinations, class-to-class differences in the severity of the cheating problem across 12 principles of economics classes, whether control measures are effective, and the relative effectiveness of deterrent measures. Considers methods for gathering data on cheating. (CMK)

Closed-Loop and Robust Control of Quantum Systems

PubMed Central

Wang, Lin-Cheng

2013-01-01

For most practical quantum control systems, it is important and difficult to attain robustness and reliability due to unavoidable uncertainties in the system dynamics or models. Three kinds of typical approaches (e.g., closed-loop learning control, feedback control, and robust control) have been proved to be effective to solve these problems. This work presents a self-contained survey on the closed-loop and robust control of quantum systems, as well as a brief introduction to a selection of basic theories and methods in this research area, to provide interested readers with a general idea for further studies. In the area of closed-loop learning control of quantum systems, we survey and introduce such learning control methods as gradient-based methods, genetic algorithms (GA), and reinforcement learning (RL) methods from a unified point of view of exploring the quantum control landscapes. For the feedback control approach, the paper surveys three control strategies including Lyapunov control, measurement-based control, and coherent-feedback control. Then such topics in the field of quantum robust control as H ∞ control, sliding mode control, quantum risk-sensitive control, and quantum ensemble control are reviewed. The paper concludes with a perspective of future research directions that are likely to attract more attention. PMID:23997680

Effects of self-management health information technology on glycaemic control for patients with diabetes: a meta-analysis of randomized controlled trials.

PubMed

Tao, Da; Or, Calvin Kl

2013-04-01

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) which had evaluated self-management health information technology (SMHIT) for glycaemic control in patients with diabetes. A total of 43 RCTs was identified, which reported on 52 control-intervention comparisons. The glycosylated haemoglobin (HbA 1c ) data were pooled using a random effects meta-analysis method, followed by a meta-regression and subgroup analyses to examine the effects of a set of moderators. The meta-analysis showed that use of SMHITs was associated with a significant reduction in HbA 1c compared to usual care, with a pooled standardized mean difference of -0.30% (95% CI -0.39 to -0.21, P < 0.001). Sample size, age, study setting, type of application and method of data entry significantly moderated the effects of SMHIT use. The review supports the use of SMHITs as a self-management approach to improve glycaemic control. The effect of SMHIT use is significantly greater when the technology is a web-based application, when a mechanism for patients' health data entry is provided (manual or automatic) and when the technology is operated in the home or without location restrictions. Integrating these variables into the design of SMHITs may augment the effectiveness of the interventions. © SAGE Publications Ltd, 2013.

A frequency control method for regulating wireless power to implantable devices.

PubMed

Ping Si; Hu, A P; Malpas, S; Budgett, D

2008-03-01

This paper presents a method to regulate the power transferred over a wireless link by adjusting the resonant operating frequency of the primary converter. A significant advantage of this method is that effective power regulation is maintained under variations in load, coupling and circuit parameters. This is particularly important when the wireless supply is used to power implanted medical devices where substantial coupling variations between internal and external systems is expected. The operating frequency is changed dynamically by altering the effective tuning capacitance through soft switched phase control. A thorough analysis of the proposed system has been undertaken, and experimental results verify its functionality.

Non-destructive control of graphite electrodes with use of current displacement effect

NASA Astrophysics Data System (ADS)

Myatezh, A. V.; Malozyomov, B. V.; Smirnov, M. A.

2017-10-01

The work is devoted to methods of nondestructive diagnostics and their use for solving the problem of diagnosing various defects in solid surface of graphite electrodes used in steelmaking furnaces. Various non-destructive control methods of materials are analyzed. In the article, methods of eddy-current defectoscopy of graphite electrodes are considered. Rationalization of the sensitivity increase of the method and localization of damage is described. Imitating modeling of electromagnetic processes was executed; results were made and conclusions were drawn.

Dynamic Control of the Vortex Pinning Potential in a Superconductor Using Current Injection through Nanoscale Patterns.

PubMed

Kalcheim, Yoav; Katzir, Eran; Zeides, Felix; Katz, Nadav; Paltiel, Yossi; Millo, Oded

2017-05-10

Control over the vortex potential at the nanoscale in a superconductor is a subject of great interest for both fundamental and technological reasons. Many methods for achieving artificial pinning centers have been demonstrated, for example, with magnetic nanostructures or engineered imperfections, yielding many intriguing effects. However, these pinning mechanisms do not offer dynamic control over the strength of the patterned vortex potential because they involve static nanostructures created in or near the superconductor. Dynamic control has been achieved with scanning probe methods on the single vortex level but these are difficult so scale up. Here, we show that by applying controllable nanopatterned current injection, the superconductor can be locally driven out of equilibrium, creating an artificial vortex potential that can be tuned by the magnitude of the injected current, yielding a unique vortex channeling effect.

A Randomized Controlled Trial Comparing the McKenzie Method to Motor Control Exercises in People With Chronic Low Back Pain and a Directional Preference.

PubMed

Halliday, Mark H; Pappas, Evangelos; Hancock, Mark J; Clare, Helen A; Pinto, Rafael Z; Robertson, Gavin; Ferreira, Paulo H

2016-07-01

Study Design Randomized clinical trial. Background Motor control exercises are believed to improve coordination of the trunk muscles. It is unclear whether increases in trunk muscle thickness can be facilitated by approaches such as the McKenzie method. Furthermore, it is unclear which approach may have superior clinical outcomes. Objectives The primary aim was to compare the effects of the McKenzie method and motor control exercises on trunk muscle recruitment in people with chronic low back pain classified with a directional preference. The secondary aim was to conduct a between-group comparison of outcomes for pain, function, and global perceived effect. Methods Seventy people with chronic low back pain who demonstrated a directional preference using the McKenzie assessment were randomized to receive 12 treatments over 8 weeks with the McKenzie method or with motor control approaches. All outcomes were collected at baseline and at 8-week follow-up by blinded assessors. Results No significant between-group difference was found for trunk muscle thickness of the transversus abdominis (-5.8%; 95% confidence interval [CI]: -15.2%, 3.7%), obliquus internus (-0.7%; 95% CI: -6.6%, 5.2%), and obliquus externus (1.2%; 95% CI: -4.3%, 6.8%). Perceived recovery was slightly superior in the McKenzie group (-0.8; 95% CI: -1.5, -0.1) on a -5 to +5 scale. No significant between-group differences were found for pain or function (P = .99 and P = .26, respectively). Conclusion We found no significant effect of treatment group for trunk muscle thickness. Participants reported a slightly greater sense of perceived recovery with the McKenzie method than with the motor control approach. Level of Evidence Therapy, level 1b-. Registered September 7, 2011 at www.anzctr.org.au (ACTRN12611000971932). J Orthop Sports Phys Ther 2016;46(7):514-522. Epub 12 May 2016. doi:10.2519/jospt.2016.6379.

Bayes and empirical Bayes methods for reduced rank regression models in matched case-control studies.

PubMed

Satagopan, Jaya M; Sen, Ananda; Zhou, Qin; Lan, Qing; Rothman, Nathaniel; Langseth, Hilde; Engel, Lawrence S

2016-06-01

Matched case-control studies are popular designs used in epidemiology for assessing the effects of exposures on binary traits. Modern studies increasingly enjoy the ability to examine a large number of exposures in a comprehensive manner. However, several risk factors often tend to be related in a nontrivial way, undermining efforts to identify the risk factors using standard analytic methods due to inflated type-I errors and possible masking of effects. Epidemiologists often use data reduction techniques by grouping the prognostic factors using a thematic approach, with themes deriving from biological considerations. We propose shrinkage-type estimators based on Bayesian penalization methods to estimate the effects of the risk factors using these themes. The properties of the estimators are examined using extensive simulations. The methodology is illustrated using data from a matched case-control study of polychlorinated biphenyls in relation to the etiology of non-Hodgkin's lymphoma. © 2015, The International Biometric Society.

The Effectiveness of an Individualized Learning Method of Instruction When Compared to the Lecture-Discussion Method. A Research Report of a Graduate Study.

ERIC Educational Resources Information Center

Oen, Urban T.; Sweany, H. Paul

To compare the effectiveness of individualized and lecture-discussion methods with a non-instruction (Control) method in developing turfgrass competencies in 11th and 12th grade students as measured by achievement in a battery of tests, teachers from 29 Michigan schools were randomly placed in three groups and attended workshops where they were…

First pulse effect self-suppression picosecond regenerative amplifier (Conference Presentation)

NASA Astrophysics Data System (ADS)

Fan, Haitao; Chang, Liang; Zhang, Yi; Yao, Siyi; Lu, Wei; Yang, Xiaohong

2017-03-01

First pulse effect, commonly seen in nanosecond cavity-dumped lasers and picosecond regenerative amplifiers, not only leads to degradation of processing quality, but also acts as potential threat to optical switching elements. Several methods have been developed to suppress that effect, including electronic controls, polarization controls, and diffraction controls. We present a new way for first pulse self-suppression without any additional components. By carefully arranging the cavity mirror of a regenerative amplifier, we realized `parasitic lasing like' radiation. When the regenerative amplifier works in `operation ready' status, the parasitic lasing occurs and prevents the gain crystal from saturation. When the regenerative amplifier starts working and amplifying pulses, the first pulse in a pulse train will not get much more gain and energy than pulses following it. As parasitic lasing disappears at the same time, the average output power of the amplifier does not significantly reduce. This cost effective method does not require any additional component. In addition, as it is not polarization dependent, this method is widely suitable for different kinds of regenerative amplifiers. It's the easiest and cheapest way to suppress first pulse effect, to the best of our knowledge.

The diabetes nutrition education study randomized controlled trial: A comparative effectiveness study of approaches to nutrition in diabetes self-management education.

PubMed

Bowen, Michael E; Cavanaugh, Kerri L; Wolff, Kathleen; Davis, Dianne; Gregory, Rebecca P; Shintani, Ayumi; Eden, Svetlana; Wallston, Ken; Elasy, Tom; Rothman, Russell L

2016-08-01

To compare the effectiveness of different approaches to nutrition education in diabetes self-management education and support (DSME/S). We randomized 150 adults with type 2 diabetes to either certified diabetes educator (CDE)-delivered DSME/S with carbohydrate gram counting or the modified plate method versus general health education. The primary outcome was change in HbA1C over 6 months. At 6 months, HbA1C improved within the plate method [-0.83% (-1.29, -0.33), P<0.001] and carbohydrate counting [-0.63% (-1.03, -0.18), P=0.04] groups but not the control group [P=0.34]. Change in HbA1C from baseline between the control and intervention groups was not significant at 6 months (carbohydrate counting, P=0.36; modified plate method, P=0.08). In a pre-specified subgroup analysis of patients with a baseline HbA1C 7-10%, change in HbA1C from baseline improved in the carbohydrate counting [-0.86% (-1.47, -0.26), P=0.006] and plate method groups [-0.76% (-1.33, -0.19), P=0.01] compared to controls. CDE-delivered DSME/S focused on carbohydrate counting or the modified plate method improved glycemic control in patients with an initial HbA1C between 7 and 10%. Both carbohydrate counting and the modified plate method improve glycemic control as part of DSME/S. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Proceedings of the 3rd Annual SCOLE Workshop

NASA Technical Reports Server (NTRS)

Taylor, Lawrence W., Jr. (Compiler)

1987-01-01

Topics addressed include: modeling and controlling the Spacecraft Control Laboratory Experiment (SCOLE) configurations; slewing maneuvers; mathematical models; vibration damping; gravitational effects; structural dynamics; finite element method; distributed parameter system; on-line pulse control; stability augmentation; and stochastic processes.

Evaluation of the Inertial Response of Variable-Speed Wind Turbines Using Advanced Simulation: Preprint

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

Scholbrock, Andrew K; Muljadi, Eduard; Gevorgian, Vahan

In this paper, we focus on the temporary frequency support effect provided by wind turbine generators (WTGs) through the inertial response. With the implemented inertial control methods, the WTG is capable of increasing its active power output by releasing parts of the stored kinetic energy when the frequency excursion occurs. The active power can be boosted temporarily above the maximum power points, but the rotor speed deceleration follows and an active power output deficiency occurs during the restoration of rotor kinetic energy. In this paper, we evaluate and compare the inertial response induced by two distinct inertial control methods usingmore » advanced simulation. In the first stage, the proposed inertial control methods are analyzed in offline simulation. Using an advanced wind turbine simulation program, FAST with TurbSim, the response of the researched wind turbine is comprehensively evaluated under turbulent wind conditions, and the impact on the turbine mechanical components are assessed. In the second stage, the inertial control is deployed on a real 600-kW wind turbine, the three-bladed Controls Advanced Research Turbine, which further verifies the inertial control through a hardware-in-the-loop simulation. Various inertial control methods can be effectively evaluated based on the proposed two-stage simulation platform, which combines the offline simulation and real-time hardware-in-the-loop simulation. The simulation results also provide insights in designing inertial control for WTGs.« less

Comparison of three different sterilization and disinfection methods on orthodontic markers

PubMed Central

Omidkhoda, Maryam; Rashed, Roozbeh; Bagheri, Zahra; Ghazvini, Kiarash; Shafaee, Hooman

2016-01-01

Background: Marking pencils which are frequently used in orthodontics may cause microbial contamination. The purpose of this study was to evaluate and compare the effectiveness of three disinfection and sterilization methods (autoclave, glutaraldehyde solution, and Deconex spray) on orthodontic markers. Materials and Methods: One hundred and twenty orthodontic markers were divided into four groups each 30 pencils: One control group and three groups for three different disinfection/sterilization methods. To evaluate the effectiveness of these methods, pencils were initially contaminated by common pathogen by immersing the pencils in a suspension containing 1.5 × 108 CFU/ml organisms. Then, the pencils were subjected to corresponding disinfection/sterilization methods, and the number of remaining microorganisms was calculated and compared with control group. Results: In the control group, the mean number of Escherichia coli was significantly higher than the other two microorganisms (P = 0.01, P = 0.031). However, the mean numbers of Staphylococcus aureus and Candida albicans were not significantly different (P = 0.1). After sterilization with autoclave and glutaraldehyde, no microbial growth was observed, whereas after disinfection with Deconx spray some colonies of microorganisms still could be observed. Conclusion: Autoclaving and glutaraldehyde solution are the best methods for disinfecting orthodontic markers. PMID:26998472

Optimal management of orthodontic pain.

PubMed

Topolski, Francielle; Moro, Alexandre; Correr, Gisele Maria; Schimim, Sasha Cristina

2018-01-01

Pain is an undesirable side effect of orthodontic tooth movement, which causes many patients to give up orthodontic treatment or avoid it altogether. The aim of this study was to investigate, through an analysis of the scientific literature, the best method for managing orthodontic pain. The methodological aspects involved careful definition of keywords and diligent search in databases of scientific articles published in the English language, without any restriction of publication date. We recovered 1281 articles. After the filtering and classification of these articles, 56 randomized clinical trials were selected. Of these, 19 evaluated the effects of different types of drugs for the control of orthodontic pain, 16 evaluated the effects of low-level laser therapy on orthodontic pain, and 21 evaluated other methods of pain control. Drugs reported as effective in orthodontic pain control included ibuprofen, paracetamol, naproxen sodium, aspirin, etoricoxib, meloxicam, piroxicam, and tenoxicam. Most studies report favorable outcomes in terms of alleviation of orthodontic pain with the use of low-level laser therapy. Nevertheless, we noticed that there is no consensus, both for the drug and for laser therapy, on the doses and clinical protocols most appropriate for orthodontic pain management. Alternative methods for orthodontic pain control can also broaden the clinician's range of options in the search for better patient care.

Optimal management of orthodontic pain

PubMed Central

Topolski, Francielle; Moro, Alexandre; Correr, Gisele Maria; Schimim, Sasha Cristina

2018-01-01

Pain is an undesirable side effect of orthodontic tooth movement, which causes many patients to give up orthodontic treatment or avoid it altogether. The aim of this study was to investigate, through an analysis of the scientific literature, the best method for managing orthodontic pain. The methodological aspects involved careful definition of keywords and diligent search in databases of scientific articles published in the English language, without any restriction of publication date. We recovered 1281 articles. After the filtering and classification of these articles, 56 randomized clinical trials were selected. Of these, 19 evaluated the effects of different types of drugs for the control of orthodontic pain, 16 evaluated the effects of low-level laser therapy on orthodontic pain, and 21 evaluated other methods of pain control. Drugs reported as effective in orthodontic pain control included ibuprofen, paracetamol, naproxen sodium, aspirin, etoricoxib, meloxicam, piroxicam, and tenoxicam. Most studies report favorable outcomes in terms of alleviation of orthodontic pain with the use of low-level laser therapy. Nevertheless, we noticed that there is no consensus, both for the drug and for laser therapy, on the doses and clinical protocols most appropriate for orthodontic pain management. Alternative methods for orthodontic pain control can also broaden the clinician’s range of options in the search for better patient care. PMID:29588616

A Study of Economical Incentives for Voltage Profile Control Method in Future Distribution Network

NASA Astrophysics Data System (ADS)

Tsuji, Takao; Sato, Noriyuki; Hashiguchi, Takuhei; Goda, Tadahiro; Tange, Seiji; Nomura, Toshio

In a future distribution network, it is difficult to maintain system voltage because a large number of distributed generators are introduced to the system. The authors have proposed “voltage profile control method” using power factor control of distributed generators in the previous work. However, the economical disbenefit is caused by the active power decrease when the power factor is controlled in order to increase the reactive power. Therefore, proper incentives must be given to the customers that corporate to the voltage profile control method. Thus, in this paper, we develop a new rules which can decide the economical incentives to the customers. The method is tested in one feeder distribution network model and its effectiveness is shown.

Multigrid one shot methods for optimal control problems: Infinite dimensional control

NASA Technical Reports Server (NTRS)

Arian, Eyal; Taasan, Shlomo

1994-01-01

The multigrid one shot method for optimal control problems, governed by elliptic systems, is introduced for the infinite dimensional control space. ln this case, the control variable is a function whose discrete representation involves_an increasing number of variables with grid refinement. The minimization algorithm uses Lagrange multipliers to calculate sensitivity gradients. A preconditioned gradient descent algorithm is accelerated by a set of coarse grids. It optimizes for different scales in the representation of the control variable on different discretization levels. An analysis which reduces the problem to the boundary is introduced. It is used to approximate the two level asymptotic convergence rate, to determine the amplitude of the minimization steps, and the choice of a high pass filter to be used when necessary. The effectiveness of the method is demonstrated on a series of test problems. The new method enables the solutions of optimal control problems at the same cost of solving the corresponding analysis problems just a few times.

An Improved Distributed Secondary Control Method for DC Microgrids With Enhanced Dynamic Current Sharing Performance

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

Wang, Panbao; Lu, Xiaonan; Yang, Xu

This paper proposes an improved distributed secondary control scheme for dc microgrids (MGs), aiming at overcoming the drawbacks of conventional droop control method. The proposed secondary control scheme can remove the dc voltage deviation and improve the current sharing accuracy by using voltage-shifting and slope-adjusting approaches simultaneously. Meanwhile, the average value of droop coefficients is calculated, and then it is controlled by an additional controller included in the distributed secondary control layer to ensure that each droop coefficient converges at a reasonable value. Hence, by adjusting the droop coefficient, each participating converter has equal output impedance, and the accurate proportionalmore » load current sharing can be achieved with different line resistances. Furthermore, the current sharing performance in steady and transient states can be enhanced by using the proposed method. The effectiveness of the proposed method is verified by detailed experimental tests based on a 3 × 1 kW prototype with three interface converters.« less

Constant-current control method of multi-function electromagnetic transmitter.

PubMed

Xue, Kaichang; Zhou, Fengdao; Wang, Shuang; Lin, Jun

2015-02-01

Based on the requirements of controlled source audio-frequency magnetotelluric, DC resistivity, and induced polarization, a constant-current control method is proposed. Using the required current waveforms in prospecting as a standard, the causes of current waveform distortion and current waveform distortion's effects on prospecting are analyzed. A cascaded topology is adopted to achieve 40 kW constant-current transmitter. The responsive speed and precision are analyzed. According to the power circuit of the transmitting system, the circuit structure of the pulse width modulation (PWM) constant-current controller is designed. After establishing the power circuit model of the transmitting system and the PWM constant-current controller model, analyzing the influence of ripple current, and designing an open-loop transfer function according to the amplitude-frequency characteristic curves, the parameters of the PWM constant-current controller are determined. The open-loop transfer function indicates that the loop gain is no less than 28 dB below 160 Hz, which assures the responsive speed of the transmitting system; the phase margin is 45°, which assures the stabilization of the transmitting system. Experimental results verify that the proposed constant-current control method can keep the control error below 4% and can effectively suppress load change caused by the capacitance of earth load.

Constant-current control method of multi-function electromagnetic transmitter

NASA Astrophysics Data System (ADS)

Xue, Kaichang; Zhou, Fengdao; Wang, Shuang; Lin, Jun

2015-02-01

Based on the requirements of controlled source audio-frequency magnetotelluric, DC resistivity, and induced polarization, a constant-current control method is proposed. Using the required current waveforms in prospecting as a standard, the causes of current waveform distortion and current waveform distortion's effects on prospecting are analyzed. A cascaded topology is adopted to achieve 40 kW constant-current transmitter. The responsive speed and precision are analyzed. According to the power circuit of the transmitting system, the circuit structure of the pulse width modulation (PWM) constant-current controller is designed. After establishing the power circuit model of the transmitting system and the PWM constant-current controller model, analyzing the influence of ripple current, and designing an open-loop transfer function according to the amplitude-frequency characteristic curves, the parameters of the PWM constant-current controller are determined. The open-loop transfer function indicates that the loop gain is no less than 28 dB below 160 Hz, which assures the responsive speed of the transmitting system; the phase margin is 45°, which assures the stabilization of the transmitting system. Experimental results verify that the proposed constant-current control method can keep the control error below 4% and can effectively suppress load change caused by the capacitance of earth load.

Active control of sound radiation from a vibrating rectangular panel by sound sources and vibration inputs - An experimental comparison

NASA Technical Reports Server (NTRS)

Fuller, C. R.; Hansen, C. H.; Snyder, S. D.

1991-01-01

Active control of sound radiation from a rectangular panel by two different methods has been experimentally studied and compared. In the first method a single control force applied directly to the structure is used with a single error microphone located in the radiated acoustic field. Global attenuation of radiated sound was observed to occur by two main mechanisms. For 'on-resonance' excitation, the control force had the effect of increasing the total panel input impedance presented to the nosie source, thus reducing all radiated sound. For 'off-resonance' excitation, the control force tends not significantly to modify the panel total response amplitude but rather to restructure the relative phases of the modes leading to a more complex vibration pattern and a decrease in radiation efficiency. For acoustic control, the second method, the number of acoustic sources required for global reduction was seen to increase with panel modal order. The mechanism in this case was that the acoustic sources tended to create an inverse pressure distribution at the panel surface and thus 'unload' the panel by reducing the panel radiation impedance. In general, control by structural inputs appears more effective than control by acoustic sources for structurally radiated noise.

What makes a contraceptive acceptable?

PubMed

Berer, M

1995-01-01

The women's health movement is developing an increasing number of negative campaigns against various contraceptive methods based on three assumptions: 1) user-controlled methods are better for women than provider-controlled methods, 2) long-acting methods are undesirable because of their susceptibility to abuse, and 3) systemic methods carry unacceptable health risks to women. While these objections have sparked helpful debate, criticizing an overreliance on such methods is one thing and calling for bans on the provision of injectables and implants and on the development of vaccine contraceptives is another. Examination of the terms "provider-controlled," "user-controlled," and "long-acting" reveals that their definitions are not as clear-cut as opponents would have us believe. Some women's health advocates find the methods that are long-acting and provider-controlled to be the most problematic. They also criticize the near 100% contraceptive effectiveness of the long-acting methods despite the fact that the goal of contraception is to prevent pregnancy. It is wrong to condemn these methods because of their link to population control policies of the 1960s, and it is important to understand that long-acting, effective methods are often beneficial to women who require contraception for 20-22 years of their lives. Arguments against systemic methods (including RU-486 for early abortion and contraceptive vaccines) rebound around issues of safety. Feminists have gone so far as to create an intolerable situation by publishing books that criticize these methods based on erroneous conclusions and faulty scientific analysis. While women's health advocates have always rightly called for bans on abuse of various methods, they have not extended this ban to the methods themselves. In settings where other methods are not available, bans can lead to harm or maternal deaths. Another perspective can be used to consider methods in terms of their relationship with the user (repeated application). While feminists have called for more barrier and natural methods, most people in the world today refuse to use condoms even though they are the best protection from infection. Instead science should pursue promising new methods as well as continue to improve existing methods and to fill important gaps. Feminists should be advocates for women and their diverse needs rather than advocates against specific contraceptive methods.

Versatile Dual Photoresponsive System for Precise Control of Chemical Reactions.

PubMed

Xu, Can; Bing, Wei; Wang, Faming; Ren, Jinsong; Qu, Xiaogang

2017-08-22

A versatile method for photoregulation of chemical reactions was developed through a combination of near-infrared (NIR) and ultraviolet (UV) light sensitive materials. This regulatory effect was achieved through photoresponsive modulation of reaction temperature and pH values, two prominent factors influencing reaction kinetics. Photothermal nanomaterial graphene oxide (GO) and photobase reagent malachite green carbinol base (MGCB) were selected for temperature and pH regulation, respectively. Using nanocatalyst- and enzyme-mediated chemical reactions as model systems, we demonstrated the feasibility and high efficiency of this method. In addition, a photoresponsive, multifunctional "Band-aid"-like hydrogel platform was presented for programmable wound healing. Overall, this simple, efficient, and reversible system was found to be effective for controlling a wide variety of chemical reactions. Our work may provide a method for remote and sustainable control over chemical reactions for industrial and biomedical applications.

Impact of Family Planning and Business Trainings on Private-Sector Health Care Providers in Nigeria.

PubMed

Ugaz, Jorge; Leegwater, Anthony; Chatterji, Minki; Johnson, Doug; Baruwa, Sikiru; Toriola, Modupe; Kinnan, Cynthia

2017-06-01

Private health care providers are an important source of modern contraceptives in Sub-Saharan Africa, yet they face many challenges that might be addressed through targeted training. This study measures the impact of a package of trainings and supportive supervision activities targeted to private health care providers in Lagos State, Nigeria, on outcomes including range of contraceptive methods offered, providers' knowledge and quality of counseling, recordkeeping practices, access to credit and revenue. A total of 965 health care facilities were randomly assigned to treatment and control groups. Facilities in the treatment group-but not those in the control group-were offered a training package that included a contraceptive technology update and interventions to improve counseling and clinical skills and business practices. Multivariate regression analysis of data collected through facility and mystery client surveys was used to estimate effects. The training program had a positive effect on the range of contraceptive methods offered, with facilities in the treatment group providing more methods than facilities in the control group. The training program also had a positive impact on the quality of counseling services, especially on the range of contraceptive methods discussed by providers, their interpersonal skills and overall knowledge. Facilities in the treatment group were more likely than facilities in the control group to have good recordkeeping practices and to have obtained loans. No effect was found on revenue generation. Targeted training programs can be effective tools to improve the provision of family planning services through private providers.

A time-domain decomposition iterative method for the solution of distributed linear quadratic optimal control problems

NASA Astrophysics Data System (ADS)

Heinkenschloss, Matthias

2005-01-01

We study a class of time-domain decomposition-based methods for the numerical solution of large-scale linear quadratic optimal control problems. Our methods are based on a multiple shooting reformulation of the linear quadratic optimal control problem as a discrete-time optimal control (DTOC) problem. The optimality conditions for this DTOC problem lead to a linear block tridiagonal system. The diagonal blocks are invertible and are related to the original linear quadratic optimal control problem restricted to smaller time-subintervals. This motivates the application of block Gauss-Seidel (GS)-type methods for the solution of the block tridiagonal systems. Numerical experiments show that the spectral radii of the block GS iteration matrices are larger than one for typical applications, but that the eigenvalues of the iteration matrices decay to zero fast. Hence, while the GS method is not expected to convergence for typical applications, it can be effective as a preconditioner for Krylov-subspace methods. This is confirmed by our numerical tests.A byproduct of this research is the insight that certain instantaneous control techniques can be viewed as the application of one step of the forward block GS method applied to the DTOC optimality system.

Effects of Mathematics Integration in a Teaching Methods Course on Mathematics Ability of Preservice Agricultural Education Teachers

ERIC Educational Resources Information Center

Stripling, Christopher T.; Roberts, T. Grady

2014-01-01

The purpose of this study was to determine the effects of incorporating mathematics teaching and integration strategies (MTIS) in a teaching methods course on preservice agricultural teachers' mathematics ability. The research design was quasi-experimental and utilized a nonequivalent control group. The MTIS treatment had a positive effect on the…

Viscous-Inviscid Methods in Unsteady Aerodynamic Analysis of Bio-Inspired Morphing Wings

NASA Astrophysics Data System (ADS)

Dhruv, Akash V.

Flight has been one of the greatest realizations of human imagination, revolutionizing communication and transportation over the years. This has greatly influenced the growth of technology itself, enabling researchers to communicate and share their ideas more effectively, extending the human potential to create more sophisticated systems. While the end product of a sophisticated technology makes our lives easier, its development process presents an array of challenges in itself. In last decade, scientists and engineers have turned towards bio-inspiration to design more efficient and robust aerodynamic systems to enhance the ability of Unmanned Aerial Vehicles (UAVs) to be operated in cluttered environments, where tight maneuverability and controllability are necessary. Effective use of UAVs in domestic airspace will mark the beginning of a new age in communication and transportation. The design of such complex systems necessitates the need for faster and more effective tools to perform preliminary investigations in design, thereby streamlining the design process. This thesis explores the implementation of numerical panel methods for aerodynamic analysis of bio-inspired morphing wings. Numerical panel methods have been one of the earliest forms of computational methods for aerodynamic analysis to be developed. Although the early editions of this method performed only inviscid analysis, the algorithm has matured over the years as a result of contributions made by prominent aerodynamicists. The method discussed in this thesis is influenced by recent advancements in panel methods and incorporates both viscous and inviscid analysis of multi-flap wings. The surface calculation of aerodynamic coefficients makes this method less computationally expensive than traditional Computational Fluid Dynamics (CFD) solvers available, and thus is effective when both speed and accuracy are desired. The morphing wing design, which consists of sequential feather-like flaps installed over the upper and lower surfaces of a standard airfoil, proves to be an effective alternative to standard control surfaces by increasing the flight capability of bird-scale UAVs. The results obtained for this wing design under various flight and flap configurations provide insight into its aerodynamic behavior, which enhance the maneuverability and controllability. The overall method acts as an important tool to create an aerodynamic database to develop a distributed control system for autonomous operation of the multi-flap morphing wing, supporting the use of viscous-inviscid methods as a tool in rapid aerodynamic analysis.

Real-Time Adaptive Control of a Magnetic Levitation System with a Large Range of Load Disturbance.

PubMed

Zhang, Zhizhou; Li, Xiaolong

2018-05-11

In an idle light-load or a full-load condition, the change of the load mass of a suspension system is very significant. If the control parameters of conventional control methods remain unchanged, the suspension performance of the control system deteriorates rapidly or even loses stability when the load mass changes in a large range. In this paper, a real-time adaptive control method for a magnetic levitation system with large range of mass changes is proposed. First, the suspension control system model of the maglev train is built up, and the stability of the closed-loop system is analyzed. Then, a fast inner current-loop is used to simplify the design of the suspension control system, and an adaptive control method is put forward to ensure that the system is still in a stable state when the load mass varies in a wide range. Simulations and experiments show that when the load mass of the maglev system varies greatly, the adaptive control method is effective to suspend the system stably with a given displacement.

Real-Time Adaptive Control of a Magnetic Levitation System with a Large Range of Load Disturbance

PubMed Central

Zhang, Zhizhou; Li, Xiaolong

2018-01-01

In an idle light-load or a full-load condition, the change of the load mass of a suspension system is very significant. If the control parameters of conventional control methods remain unchanged, the suspension performance of the control system deteriorates rapidly or even loses stability when the load mass changes in a large range. In this paper, a real-time adaptive control method for a magnetic levitation system with large range of mass changes is proposed. First, the suspension control system model of the maglev train is built up, and the stability of the closed-loop system is analyzed. Then, a fast inner current-loop is used to simplify the design of the suspension control system, and an adaptive control method is put forward to ensure that the system is still in a stable state when the load mass varies in a wide range. Simulations and experiments show that when the load mass of the maglev system varies greatly, the adaptive control method is effective to suspend the system stably with a given displacement. PMID:29751610

A concept for adaptive performance optimization on commercial transport aircraft

NASA Technical Reports Server (NTRS)

Jackson, Michael R.; Enns, Dale F.

1995-01-01

An adaptive control method is presented for the minimization of drag during flight for transport aircraft. The minimization of drag is achieved by taking advantage of the redundant control capability available in the pitch axis, with the horizontal tail used as the primary surface and symmetric deflection of the ailerons and cruise flaps used as additional controls. The additional control surfaces are excited with sinusoidal signals, while the altitude and velocity loops are closed with guidance and control laws. A model of the throttle response as a function of the additional control surfaces is formulated and the parameters in the model are estimated from the sensor measurements using a least squares estimation method. The estimated model is used to determine the minimum drag positions of the control surfaces. The method is presented for the optimization of one and two additional control surfaces. The adaptive control method is extended to optimize rate of climb with the throttle fixed. Simulations that include realistic disturbances are presented, as well as the results of a Monte Carlo simulation analysis that shows the effects of changing the disturbance environment and the excitation signal parameters.

IEEE 1990 International Symposium on Electromagnetic Compatibility, Washington, DC, Aug. 21-23, 1990, Record

NASA Astrophysics Data System (ADS)

The present conference discusses topics in EM shielding effectiveness, system-level EMC, EMP effects, circuit-level EMI testing, EMI control, analysis techniques for system-level EMC, EMP protective measures, EMI test methods, electrostatic-discharge testing, printed circuit-board design for EMC, and EM environment effects. Also discussed are EMI measurement procedures, EM spectrum-management issues for the 21st century, antenna and propagation effects on EMI testing, EMI control in cables, socioeconomic aspects of EMC, systemwide EMI controls, and EM radiation and coupling.

Spray characterization of thermal fogging equipment typically used in vector control

USDA-ARS?s Scientific Manuscript database

The generation of insecticide laden fogs provides an effective method for controlling flying insects. One of the critical factors affecting the effectiveness of a thermal fogging application is the generation of droplets that will remain aloft in the fogging cloud and moves into the area where the ...

Health Instruction Packages: Consumer--Birth Control.

ERIC Educational Resources Information Center

Pries, Rose Mary; And Others

Designed for the general public, these three learning modules utilize text, illustrations, and exercises to describe various methods of birth control. The first module, "All about Contraception for the Teenage New Mother" by Rose Mary Pries, discusses the desirability of planned pregnancy and reviews the effectiveness and side effects of…

Testing Public Anxiety Treatments against a Credible Placebo Control

ERIC Educational Resources Information Center

Duff, Desiree C.; Levine, Timothy R.; Beatty, Michael J.; Woolbright, Jessica; Park, Hee Sun

2007-01-01

Research investigating public speaking anxiety treatments is subject to demand effects. This study tests the relative effectiveness of systematic desensitization (SD) and multiple treatment method (MT) containing visualization therapy against no-treatment and credible placebo controls. Data (N = 238) were collected at six points in a public…

OZONE AMBIENT AIR QUALITY STANDARD HAS BENEFICIAL EFFECT ON PONDEROSA PINE IN CALIFORNIA

EPA Science Inventory

Ambient air quality standards and control strategies are implemented to protect humans and vegetation from adverse effects. However, to date there has not been a simple and objective method to determine if the standards and resultant control strategies have reduced O3 impacts on ...

The Effect of Schooling and Ability on Achievement Test Scores. NBER Working Paper Series.

ERIC Educational Resources Information Center

Hansen, Karsten; Heckman, James J.; Mullen, Kathleen J.

This study developed two methods for estimating the effect of schooling on achievement test scores that control for the endogeneity of schooling by postulating that both schooling and test scores are generated by a common unobserved latent ability. The methods were applied to data on schooling and test scores. Estimates from the two methods are in…

Mutation particle swarm optimization of the BP-PID controller for piezoelectric ceramics

NASA Astrophysics Data System (ADS)

Zheng, Huaqing; Jiang, Minlan

2016-01-01

PID control is the most common used method in industrial control because its structure is simple and it is easy to implement. PID controller has good control effect, now it has been widely used. However, PID method has a few limitations. The overshoot of the PID controller is very big. The adjustment time is long. When the parameters of controlled plant are changing over time, the parameters of controller could hardly change automatically to adjust to changing environment. Thus, it can't meet the demand of control quality in the process of controlling piezoelectric ceramic. In order to effectively control the piezoelectric ceramic and improve the control accuracy, this paper replaced the learning algorithm of the BP with the mutation particle swarm optimization algorithm(MPSO) on the process of the parameters setting of BP-PID. That designed a better self-adaptive controller which is combing the BP neural network based on mutation particle swarm optimization with the conventional PID control theory. This combination is called the MPSO-BP-PID. In the mechanism of the MPSO, the mutation operation is carried out with the fitness variance and the global best fitness value as the standard. That can overcome the precocious of the PSO and strengthen its global search ability. As a result, the MPSO-BP-PID can complete controlling the controlled plant with higher speed and accuracy. Therefore, the MPSO-BP-PID is applied to the piezoelectric ceramic. It can effectively overcome the hysteresis, nonlinearity of the piezoelectric ceramic. In the experiment, compared with BP-PID and PSO-BP-PID, it proved that MPSO is effective and the MPSO-BP-PID has stronger adaptability and robustness.

Autocorrelated process control: Geometric Brownian Motion approach versus Box-Jenkins approach

NASA Astrophysics Data System (ADS)

Salleh, R. M.; Zawawi, N. I.; Gan, Z. F.; Nor, M. E.

2018-04-01

Existing of autocorrelation will bring a significant effect on the performance and accuracy of process control if the problem does not handle carefully. When dealing with autocorrelated process, Box-Jenkins method will be preferred because of the popularity. However, the computation of Box-Jenkins method is too complicated and challenging which cause of time-consuming. Therefore, an alternative method which known as Geometric Brownian Motion (GBM) is introduced to monitor the autocorrelated process. One real case of furnace temperature data is conducted to compare the performance of Box-Jenkins and GBM methods in monitoring autocorrelation process. Both methods give the same results in terms of model accuracy and monitoring process control. Yet, GBM is superior compared to Box-Jenkins method due to its simplicity and practically with shorter computational time.

Study on Noise Prediction Model and Control Schemes for Substation

PubMed Central

Gao, Yang; Liu, Songtao

2014-01-01

With the government's emphasis on environmental issues of power transmission and transformation project, noise pollution has become a prominent problem now. The noise from the working transformer, reactor, and other electrical equipment in the substation will bring negative effect to the ambient environment. This paper focuses on using acoustic software for the simulation and calculation method to control substation noise. According to the characteristics of the substation noise and the techniques of noise reduction, a substation's acoustic field model was established with the SoundPLAN software to predict the scope of substation noise. On this basis, 4 reasonable noise control schemes were advanced to provide some helpful references for noise control during the new substation's design and construction process. And the feasibility and application effect of these control schemes can be verified by using the method of simulation modeling. The simulation results show that the substation always has the problem of excessive noise at boundary under the conventional measures. The excess noise can be efficiently reduced by taking the corresponding noise reduction methods. PMID:24672356

Effects of Pilates method in elderly people: Systematic review of randomized controlled trials.

PubMed

de Oliveira Francisco, Cristina; de Almeida Fagundes, Alessandra; Gorges, Bruna

2015-07-01

The Pilates method has been widely used in physical training and rehabilitation. Evidence regarding the effectiveness of this method in elderly people is limited. Six randomized controlled trials studies involving the use of the Pilates method for elderly people, published prior to December 2013, were selected from the databases PubMed, MEDLINE, Embase, Cochrane, Scielo and PEDro. Three articles suggested that Pilates produced improvements in balance. Two studies evaluated the adherence to Pilates programs. One study assessed Pilates' influence on cardio-metabolic parameters and another study evaluated changes in body composition. Strong evidence was found regarding beneficial effects of Pilates over static and dynamic balance in women. Nevertheless, evidence of balance improvement in both genders, changes in body composition in woman and adherence to Pilates programs were limited. Effects on cardio-metabolic parameters due to Pilates training presented inconclusive results. Pilates may be a useful tool in rehabilitation and prevention programs but more high quality studies are necessary to establish all the effects on elderly populations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Economic Model Predictive Control of Bihormonal Artificial Pancreas System Based on Switching Control and Dynamic R-parameter.

PubMed

Tang, Fengna; Wang, Youqing

2017-11-01

Blood glucose (BG) regulation is a long-term task for people with diabetes. In recent years, more and more researchers have attempted to achieve automated regulation of BG using automatic control algorithms, called the artificial pancreas (AP) system. In clinical practice, it is equally important to guarantee the treatment effect and reduce the treatment costs. The main motivation of this study is to reduce the cure burden. The dynamic R-parameter economic model predictive control (R-EMPC) is chosen to regulate the delivery rates of exogenous hormones (insulin and glucagon). It uses particle swarm optimization (PSO) to optimize the economic cost function and the switching logic between insulin delivery and glucagon delivery is designed based on switching control theory. The proposed method is first tested on the standard subject; the result is compared with the switching PID and the switching MPC. The effect of the dynamic R-parameter on improving the control performance is illustrated by comparing the results of the EMPC and the R-EMPC. Finally, the robustness tests on meal change (size and timing), hormone sensitivity (insulin and glucagon), and subject variability are performed. All results show that the proposed method can improve the control performance and reduce the economic costs. The simulation results verify the effectiveness of the proposed algorithm on improving the tracking performance, enhancing robustness, and reducing economic costs. The method proposed in this study owns great worth in practical application.

[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.

30 CFR 75.203 - Mining methods.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Mining methods. 75.203 Section 75.203 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.203 Mining methods. (a) The method of mining... faulty pillar recovery methods. Pillar dimensions shall be compatible with effective control of the roof...

30 CFR 75.203 - Mining methods.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Mining methods. 75.203 Section 75.203 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.203 Mining methods. (a) The method of mining... faulty pillar recovery methods. Pillar dimensions shall be compatible with effective control of the roof...

30 CFR 75.203 - Mining methods.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Mining methods. 75.203 Section 75.203 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.203 Mining methods. (a) The method of mining... faulty pillar recovery methods. Pillar dimensions shall be compatible with effective control of the roof...

30 CFR 75.203 - Mining methods.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Mining methods. 75.203 Section 75.203 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.203 Mining methods. (a) The method of mining... faulty pillar recovery methods. Pillar dimensions shall be compatible with effective control of the roof...

30 CFR 75.203 - Mining methods.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Mining methods. 75.203 Section 75.203 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.203 Mining methods. (a) The method of mining... faulty pillar recovery methods. Pillar dimensions shall be compatible with effective control of the roof...

Some Inspection Methods for Quality Control and In-service Inspection of GLARE

NASA Astrophysics Data System (ADS)

Sinke, J.

2003-07-01

Quality control of materials and structures is an important issue, also for GLARE. During the manufacturing stage the processes and materials should be monitored and checked frequently in order to obtain a qualified product. During the operation of the aircraft, frequent monitoring and inspections are performed to maintain the quality at a prescribed level. Therefore, in-service inspection methods are applied, and when necessary repair activities are conducted. For the quality control of the GLARE panels and components during manufacturing, the C-scan method proves to be an effective tool. For in-service inspection the Eddy Current Method is one of the suitable options. In this paper a brief overview is presented of both methods and their application on GLARE products.

[Clinical effects of shen-nourishing and menstruation-regulating method combined with triptorelin acetate injection on patient with luteinized unruptured follicle syndrome].

PubMed

Yan-hua, Chen; Fang, Lian; Shi, Na

2011-12-01

To study the clinical effects of Shen-nourishing and menstruation-regulating method (SNMRM) combined with Triptorelin Acetate Injection (TAI) on patients with luteinized unruptured follicle syndrome (LUFS). Sixty-two LUFS patients were randomly assigned to the treatment group and the control group. TAI was given to patients in the control group while SNMRM + TAI was given to those in the treatment group. The ovulation rate and the pregnancy rate were observed in the two groups. The ovulation rate in the treatment group was higher than that in the control group, but without significant difference (85.53% versus 79.07%, P > 0.05). The pregnancy rate was significantly higher in the treatment group than in the control group (56.25% vs 30.00%, P < 0.05). Treatment of LUFS by SNMRM + TAI could improve the ovulation rate and the pregnancy rate, indicating that LUFS patients' ovary functions could be improved by using different menstruation regulating methods during different follicular development phases.

The differential effects of teaching addition through strategy instruction versus drill and practice to students with and without learning disabilities.

PubMed

Tournaki, Nelly

2003-01-01

Forty-two second-grade general education students and 42 students with learning disabilities (LD) were taught basic, one-digit addition facts (e.g., 5 + 3 = _). Students received instruction via (a) a minimum addend strategy, (b) drill and practice, or (c) control. The effectiveness of the two methods was measured through students' accuracy and latency scores on a posttest and a transfer task (e.g., 5 + 3 + 7 =_). Students with LD improved significantly only in the strategy condition, as compared to drill-and-practice and control conditions, whereas general education students improved significantly both in the strategy and the drill-and-practice conditions as compared to the control condition. However, in the transfer task, students from all groups became significantly more accurate only in the strategy condition, while all students were significantly faster than their control group peers regardless of teaching method. The implications for teachers' differential choices of methods of instruction for students with different learning characteristics are discussed.

Active disturbance rejection controller for chemical reactor

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

Both, Roxana; Dulf, Eva H.; Muresan, Cristina I., E-mail: roxana.both@aut.utcluj.ro

2015-03-10

In the petrochemical industry, the synthesis of 2 ethyl-hexanol-oxo-alcohols (plasticizers alcohol) is of high importance, being achieved through hydrogenation of 2 ethyl-hexenal inside catalytic trickle bed three-phase reactors. For this type of processes the use of advanced control strategies is suitable due to their nonlinear behavior and extreme sensitivity to load changes and other disturbances. Due to the complexity of the mathematical model an approach was to use a simple linear model of the process in combination with an advanced control algorithm which takes into account the model uncertainties, the disturbances and command signal limitations like robust control. However themore » resulting controller is complex, involving cost effective hardware. This paper proposes a simple integer-order control scheme using a linear model of the process, based on active disturbance rejection method. By treating the model dynamics as a common disturbance and actively rejecting it, active disturbance rejection control (ADRC) can achieve the desired response. Simulation results are provided to demonstrate the effectiveness of the proposed method.« less

The Supply of Birth Control Methods, Education, and Fertility: Evidence from Romania

ERIC Educational Resources Information Center

Pop-Eleches, Cristian

2010-01-01

This paper investigates the effect of the supply of birth control methods on fertility behavior by examining Romania's 23-year period of pronatalist policies. Following the lifting of the restrictions in 1989 the immediate decrease in fertility was 30 percent. Women who spent most of their reproductive years under the restrictive regime…

Randomized Controlled Trial of Teaching Methods: Do Classroom Experiments Improve Economic Education in High Schools?

ERIC Educational Resources Information Center

Eisenkopf, Gerald; Sulser, Pascal A.

2016-01-01

The authors present results from a comprehensive field experiment at Swiss high schools in which they compare the effectiveness of teaching methods in economics. They randomly assigned classes into an experimental and a conventional teaching group, or a control group that received no specific instruction. Both teaching treatments improve economic…

Measurement of control system response using an analog operational circuit

NASA Technical Reports Server (NTRS)

Lalli, V. R.

1978-01-01

Ten basic steps are established for an analog method that measures control system response parameters. An example shows how these steps were used on a speed control portion of an auxiliary power unit. The equations and calculations necessary to describe this subsystem are given. The mechanization schematic and simulation diagram for obtaining the measured response parameters of the control system using an analog circuit are explained. Methods for investigating the various effects of the control parameters are described. It is concluded that the optimum system should be underdamped enough to be slightly oscillatory during transients.

On the effects of basic platform design characteristics on floating offshore wind turbine control and their mitigation

NASA Astrophysics Data System (ADS)

Olondriz, Joannes; Elorza, Iker; Trojaola, Ignacio; Pujana, Aron; Landaluze, Joseba

2016-09-01

Semi-submersible floating offshore wind turbines present significant advantages over other designs in terms of cost, deployment, maintenance and site-independence. However, these advantages are achieved by shifting a part of the burden of stabilising the platform pitch and roll motions to the turbine control system. A study is presented here of the effects of basic platform dimensions on the performance of a standard pitch controller and the possible methods for mitigating said effects.

Market-oriented Programming Using Small-world Networks for Controlling Building Environments

NASA Astrophysics Data System (ADS)

Shigei, Noritaka; Miyajima, Hiromi; Osako, Tsukasa

The market model, which is one of the economic activity models, is modeled as an agent system, and applying the model to the resource allocation problem has been studied. For air conditioning control of building, which is one of the resource allocation problems, an effective method based on the agent system using auction has been proposed for traditional PID controller. On the other hand, it has been considered that this method is performed by decentralized control. However, its decentralization is not perfect, and its performace is not enough. In this paper, firstly, we propose a perfectly decentralized agent model and show its performance. Secondly, in order to improve the model, we propose the agent model based on small-world model. The effectiveness of the proposed model is shown by simulation.

Meteorological Measurements from Satellite Platforms. [stability and control of flexible stochastic satellites

NASA Technical Reports Server (NTRS)

Suomi, V. E.

1975-01-01

The stability of stochastic satellites and the stability and control of flexible satellites were investigated. The effects of random environmental torques and noises in the moments of inertia of spinning and three-axes stabilized satellites were first compared analytically by four methods and by analog simulations. Among the analytical methods, it was shown that the Fokker-Planck formulation yields predictions which most coincide with the simulation results. It was then shown that the required stability criterion of a satellite is quite different from that obtained by a deterministic approach, under the assumption that the environmental and control torques experienced by the satellite are random. Finally, it was demonstrated that, by monitoring the deformations of the flexible elements of a satellite, the effectiveness of the satellite control system can be increased considerably.

SUMMARY REPORT CONTROL OF NOX EMISSIONS BY REBURNING

EPA Science Inventory

This report covers NO_x control employing reburning technology: A new, effective method of controlling NO_x emissions from a wide range of stationary combustion sources including large, coal-fired, utility boilers. Although reburning potentially is applicable ...

[Effect analysis on the two total load control methods for poisonous heavy metals].

PubMed

Fu, Guo-Wei

2012-12-01

Firstly it should be made clear that implementation of source total load control for the first type of pollutants is necessary for environmental pollution control legislation and economic structure regulation. This kind of surveillance method has been more practical to be implemented since the Manual of the Industry Discharge Coefficient of First National Pollution Sources Investigation was published. The source total load control and water environment total load control are independent of each other and none of them is redundant, on the other side they can be complementary to each other. In the present, some local planning managers are blurring and confusing the contents and styles of the two surveillance methods. They just use the water total load control to manage all the pollutants, and source total load control is discarded, which results in the loss of control for the first type of pollutants especially for the drinking water source surveillance. There is a big difference between the water quality standards and the water environmental background concentration values for the first type of pollutants in the Environmental quality standard for surface water (GB 3838-88), which means that there are problems such as "relaxing the pollutant discharge permit" and "risk induced by valence state change". Taking an enterprise with 10t electrolytic lead production capacity as an example, there is a big difference between the allowable lead discharged loads by the two total load surveillance methods. In summary, it will bring a lot of harmful effects if the water total load control is implemented for the two types of pollutants, so the source total load control and water environmental total load control should be implemented strictly at the same time.

Effect of integrated pest management on controlling zoonotic cutaneous leishmaniasis in Emamzadeh Agha Ali Abbas (AS) District, Isfahan province, 2006-2009.

PubMed

Nilforoushzadeh, Mohammad Ali; Shirani-Bidabadi, Leila; Saberi, Sedigheh; Hosseini, Seyed Mohsen; Jaffary, Fariba

2014-01-01

Cutaneous leishmaniasis (CL) is still considered as a health problem in the world. Several methods of control in different regions, together with obtaining integrated information on its natural foci, are needed to decrease its prevalence. This study was designed to evaluate the effects of simultaneous interventions on CL control. A standard questionnaire was used to identify patients among pilgrims to Emamzadeh Agha Ali Abbas (Isfahan Province, Iran). Subsequently, three methods of controlling the disease, including, spraying residential buildings with Baygon, baiting with zinc phosphide poisons, changing the vegetative cover of the region, improving the environment, and mounting a mesh on all doors and windows of buildings in residential areas were used. The control measures were then evaluated by comparing the number of pilgrims affected by CL after and before the interventions. While 23 pilgrims (1.4%) were affected with CL before the intervention (pretest), five (0.3%) persons were found to have CL after taking control measures. The Chi-square test did not indicate any significant difference in the relative frequency of CL (P = 0.731). The only scientific method for preventing and controlling zoonotic CL (ZCL) is a combination of the control methods (improving the environment and fighting off the disease districts and vectors) together with changing the vegetative cover of the region. Any measure for controlling this disease must be taken and programmed in accordance with the relevant experts' views, in coordination with the participation of other organizations and the society.

Nonlinear fractional order proportion-integral-derivative active disturbance rejection control method design for hypersonic vehicle attitude control

NASA Astrophysics Data System (ADS)

Song, Jia; Wang, Lun; Cai, Guobiao; Qi, Xiaoqiang

2015-06-01

Near space hypersonic vehicle model is nonlinear, multivariable and couples in the reentry process, which are challenging for the controller design. In this paper, a nonlinear fractional order proportion integral derivative (NFOPIλDμ) active disturbance rejection control (ADRC) strategy based on a natural selection particle swarm (NSPSO) algorithm is proposed for the hypersonic vehicle flight control. The NFOPIλDμ ADRC method consists of a tracking-differentiator (TD), an NFOPIλDμ controller and an extended state observer (ESO). The NFOPIλDμ controller designed by combining an FOPIλDμ method and a nonlinear states error feedback control law (NLSEF) is to overcome concussion caused by the NLSEF and conversely compensate the insufficiency for relatively simple and rough signal processing caused by the FOPIλDμ method. The TD is applied to coordinate the contradiction between rapidity and overshoot. By attributing all uncertain factors to unknown disturbances, the ESO can achieve dynamic feedback compensation for these disturbances and thus reduce their effects. Simulation results show that the NFOPIλDμ ADRC method can make the hypersonic vehicle six-degree-of-freedom nonlinear model track desired nominal signals accurately and fast, has good stability, dynamic properties and strong robustness against external environmental disturbances.

Two nonlinear control schemes contrasted on a hydrodynamiclike model

NASA Technical Reports Server (NTRS)

Keefe, Laurence R.

1993-01-01

The principles of two flow control strategies, those of Huebler (Luescher and Huebler, 1989) and of Ott et al. (1990) are discussed, and the two schemes are compared for their ability to control shear flow, using fully developed and transitional solutions of the Ginzburg-Landau equation as models for such flows. It was found that the effectiveness of both methods in obtaining control of fully developed flows depended strongly on the 'distance' in state space between the uncontrolled flow and goal dynamics. There were conceptual difficulties in applying the Ott et al. method to transitional convectively unstable flows. On the other hand, the Huebler method worked well, within certain limitations, although at a large cost in energy terms.

Control theory based airfoil design for potential flow and a finite volume discretization

NASA Technical Reports Server (NTRS)

Reuther, J.; Jameson, A.

1994-01-01

This paper describes the implementation of optimization techniques based on control theory for airfoil design. In previous studies it was shown that control theory could be used to devise an effective optimization procedure for two-dimensional profiles in which the shape is determined by a conformal transformation from a unit circle, and the control is the mapping function. The goal of our present work is to develop a method which does not depend on conformal mapping, so that it can be extended to treat three-dimensional problems. Therefore, we have developed a method which can address arbitrary geometric shapes through the use of a finite volume method to discretize the potential flow equation. Here the control law serves to provide computationally inexpensive gradient information to a standard numerical optimization method. Results are presented, where both target speed distributions and minimum drag are used as objective functions.

The Effect of Music on Anxiety and Cardiovascular Indices in Patients Undergoing Coronary Artery Bypass Graft: A Randomized Controlled Trial

PubMed Central

Heidari, Saeide; Babaii, Atye; Abbasinia, Mohammad; Shamali, Mahdi; Abbasi, Mohammad; Rezaei, Mahboobe

2015-01-01

Background: The instability of cardiovascular indices and anxiety disorders are common among patients undergoing coronary artery bypass graft (CABG) and could interfere with their recovery. Therefore, improving the cardiovascular indices and anxiety is essential. Objectives: This study aimed to investigate the effect of music therapy on anxiety and cardiovascular indices in patients undergoing CABG. Patients and Methods: In this randomized controlled trial, 60 patients hospitalized in the cardiovascular surgical intensive care unit of Shahid Beheshti Hospital in Qom city, Iran, in 2013 were selected using a consecutive sampling method and randomly allocated into the experimental and control groups. In the experimental group, patients received 30 minutes of light music, whereas in the control group, patients had 30 minutes of rest in bed. The cardiovascular indices and anxiety were measured immediately before, immediately after and half an hour after the study. Data were analyzed using the chi-square test and repeated measures analysis of variance. Results: Compared to the immediately before intervention, the mean anxiety scores immediately after and 30 minutes after the intervention were significantly lower in the experimental group (P < 0.037) while it did not significantly change in the control group. However, there were no significant differences regarding the cardiovascular indices in the three consecutive measurements (P > 0.05). Conclusions: Music therapy is effective in decreasing anxiety among patients undergoing CABG. However, the intervention was not effective on cardiovascular indices. Music can effectively be used as a non-pharmacological method to manage anxiety after CABG. PMID:26835471

A meta-analysis of the effects of non-traditional teaching methods on the critical thinking abilities of nursing students.

PubMed

Lee, JuHee; Lee, Yoonju; Gong, SaeLom; Bae, Juyeon; Choi, Moonki

2016-09-15

Scientific framework is important in designing curricula and evaluating students in the field of education and clinical practice. The purpose of this study was to examine the effectiveness of non-traditional educational methods on critical thinking skills. A systematic review approach was applied. Studies published in peer-reviewed journals from January 2001 to December 2014 were searched using electronic databases and major education journals. A meta-analysis was performed using Review Manager 5.2. Reviewing the included studies, the California Critical Thinking Dispositions Inventory (CCTDI) and California Critical Thinking Skills Test (CCTST) were used to assess the effectiveness of critical thinking in the meta-analysis. The eight CCTDI datasets showed that non- traditional teaching methods (i.e., no lectures) were more effective compared to control groups (standardized mean difference [SMD]: 0.42, 95 % confidence interval [CI]: 0.26-0.57, p < .00001). And six CCTST datasets showed the teaching and learning methods in these studies were also had significantly more effects when compared to the control groups (SMD: 0.29, 95 % CI: 0.10-0.48, p = 0.003). This research showed that new teaching and learning methods designed to improve critical thinking were generally effective at enhancing critical thinking dispositions.

Evaluation of Ares-I Control System Robustness to Uncertain Aerodynamics and Flex Dynamics

NASA Technical Reports Server (NTRS)

Jang, Jiann-Woei; VanTassel, Chris; Bedrossian, Nazareth; Hall, Charles; Spanos, Pol

2008-01-01

This paper discusses the application of robust control theory to evaluate robustness of the Ares-I control systems. Three techniques for estimating upper and lower bounds of uncertain parameters which yield stable closed-loop response are used here: (1) Monte Carlo analysis, (2) mu analysis, and (3) characteristic frequency response analysis. All three methods are used to evaluate stability envelopes of the Ares-I control systems with uncertain aerodynamics and flex dynamics. The results show that characteristic frequency response analysis is the most effective of these methods for assessing robustness.

Self-Tuning Methods for Multiple-Controller Systems.

DTIC Science & Technology

1981-08-01

the model. The plant is governed by y(t) + Aly (t-l) - B 0u(t-l) + e(t) - where -0.99101 8.80512 x 103 A1 i.. "+-0.80610 -0.77089 -0.89889 -4.59328 x 10...AC-19, No. 5, Oct. 1974, pp. 518-524. [8 Bar- Shalom , Y. and Tse, E., "Dual Effect, Certainty Equivalence and Separation in Stochastic Control," IEEE...Trans. on Automatic Control, Vol. AC-19, No. 5, Oct. 1974, pp. 494-500. [9) Bar- Shalom , Y. and Tse, E., "Concepts and Methods in Stochastic Control

On the feasibility of the Chevron Notch Beam method to measure fracture toughness of fine-grained zirconia ceramics.

PubMed

Kailer, Andreas; Stephan, Marc

2016-10-01

The fracture toughness determination of fine-grained zirconia ceramics using the chevron notched beam method (CNB) was investigated to assess the feasibility of this method for quality assurance and material characterization. CNB tests were performed using four different yttria-stabilized zirconia ceramics under various testing modes and conditions, including displacement-controlled and load-rate-controlled four point bending to assess the influence of slow crack growth and identify most suitable test parameters. For comparison, tests using single-edge V-notch beams (SEVNB) were conducted. It was observed that the CNB method yields well-reproducible results. However, slow crack growth effects significantly affect the measured KIC values, especially when slow loading rates are used. To minimize the effect of slow crack growth, the application of high loading rates is recommended. Despite a certain effort needed for setting up a sample preparation routine, the CNB method is considered to be very useful for measuring and controlling the fracture toughness of zirconia ceramics. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Adaptive controller for a strength testbed for aircraft structures

NASA Astrophysics Data System (ADS)

Laperdin, A. I.; Yurkevich, V. D.

2017-07-01

The problem of control system design for a strength testbed of aircraft structures is considered. A method for calculating the parameters of a proportional-integral controller (control algorithm) using the time-scale separation method for the testbed taking into account the dead time effect in the control loop is presented. An adaptive control algorithm structure is proposed which limits the amplitude of high-frequency oscillations in the control system with a change in the direction of motion of the rod of the hydraulic cylinders and provides the desired accuracy and quality of transients at all stages of structural loading history. The results of tests of the developed control system with the adaptive control algorithm on an experimental strength testbed for aircraft structures are given.

Effects of Management Practices on Meloidogyne incognita and Snap Bean Yield.

PubMed

Smittle, D A; Johnson, A W

1982-01-01

Phenamiphos applied at 6.7 kg ai/ha through a solid set or a center pivot irrigation system with 28 mm of water effectively controlled root-knot nematodes, Meloidogyne incognita, and resulted in greater snap bean growth and yields irrespective of growing season, tillage method, or cover crop system. The percentage yield increases attributed to this method of M. incognita control over nontreated controls were 45% in the spring crop, and 90% and 409% in the fall crops following winter rye and fallow, respectively. Root galling was not affected by tillage systems or cover crop, but disk tillage resulted in over 50% reduction in bean yield compared with yields from the subsoil-bed tillage system.

Complementary and Alternative Approaches to Pain Relief During Labor

PubMed Central

Theau-Yonneau, Anne

2007-01-01

This review evaluated the effect of complementary and alternative medicine on pain during labor with conventional scientific methods using electronic data bases through 2006 were used. Only randomized controlled trials with outcome measures for labor pain were kept for the conclusions. Many studies did not meet the scientific inclusion criteria. According to the randomized control trials, we conclude that for the decrease of labor pain and/or reduction of the need for conventional analgesic methods: (i) There is an efficacy found for acupressure and sterile water blocks. (ii) Most results favored some efficacy for acupuncture and hydrotherapy. (iii) Studies for other complementary or alternative therapies for labor pain control have not shown their effectiveness. PMID:18227907

Teenagers and contraception.

PubMed

Rozenbaum, H

Early sexual activity in young women has created new problems in contraception and gynecologic pathology for physicians. None of the existing birth control methods seems ideally adapted to the young: oran contraceptives, the only infallible method, may present adverse effects. Intrauterine devices may result in expulsion or infection. Diaphragms or spermicides are less effective and not always well accepted by young girls. The physician, however, must bear in mind that whatever inconvenience may result, birth control is always preferable to an unwanted pregnancy or to abortion. Given the seemingly growing incidence of veneral disease and of abnormalities of cervical cytology, physicians must exercise the utmost care and consider a birth control consultation by a young girl as a full medical act.

Planner-Based Control of Advanced Life Support Systems

NASA Technical Reports Server (NTRS)

Muscettola, Nicola; Kortenkamp, David; Fry, Chuck; Bell, Scott

2005-01-01

The paper describes an approach to the integration of qualitative and quantitative modeling techniques for advanced life support (ALS) systems. Developing reliable control strategies that scale up to fully integrated life support systems requires augmenting quantitative models and control algorithms with the abstractions provided by qualitative, symbolic models and their associated high-level control strategies. This will allow for effective management of the combinatorics due to the integration of a large number of ALS subsystems. By focusing control actions at different levels of detail and reactivity we can use faster: simpler responses at the lowest level and predictive but complex responses at the higher levels of abstraction. In particular, methods from model-based planning and scheduling can provide effective resource management over long time periods. We describe reference implementation of an advanced control system using the IDEA control architecture developed at NASA Ames Research Center. IDEA uses planning/scheduling as the sole reasoning method for predictive and reactive closed loop control. We describe preliminary experiments in planner-based control of ALS carried out on an integrated ALS simulation developed at NASA Johnson Space Center.

Do biological-based strategies hold promise to biofouling control in MBRs?

PubMed

Malaeb, Lilian; Le-Clech, Pierre; Vrouwenvelder, Johannes S; Ayoub, George M; Saikaly, Pascal E

2013-10-01

Biofouling in membrane bioreactors (MBRs) remains a primary challenge for their wider application, despite the growing acceptance of MBRs worldwide. Research studies on membrane fouling are extensive in the literature, with more than 200 publications on MBR fouling in the last 3 years; yet, improvements in practice on biofouling control and management have been remarkably slow. Commonly applied cleaning methods are only partially effective and membrane replacement often becomes frequent. The reason for the slow advancement in successful control of biofouling is largely attributed to the complex interactions of involved biological compounds and the lack of representative-for-practice experimental approaches to evaluate potential effective control strategies. Biofouling is driven by microorganisms and their associated extra-cellular polymeric substances (EPS) and microbial products. Microorganisms and their products convene together to form matrices that are commonly treated as a black box in conventional control approaches. Biological-based antifouling strategies seem to be a promising constituent of an effective integrated control approach since they target the essence of biofouling problems. However, biological-based strategies are in their developmental phase and several questions should be addressed to set a roadmap for translating existing and new information into sustainable and effective control techniques. This paper investigates membrane biofouling in MBRs from the microbiological perspective to evaluate the potential of biological-based strategies in offering viable control alternatives. Limitations of available control methods highlight the importance of an integrated anti-fouling approach including biological strategies. Successful development of these strategies requires detailed characterization of microorganisms and EPS through the proper selection of analytical tools and assembly of results. Existing microbiological/EPS studies reveal a number of implications as well as knowledge gaps, warranting future targeted research. Systematic and representative microbiological studies, complementary utilization of molecular and biofilm characterization tools, standardized experimental methods and validation of successful biological-based antifouling strategies for MBR applications are needed. Specifically, in addition, linking these studies to relevant operational conditions in MBRs is an essential step to ultimately develop a better understanding and more effective and directed control strategy for biofouling. Copyright © 2013 Elsevier Ltd. All rights reserved.

Insecticidal effects of deltamethrin in laboratory and field populations of Culicoides species: how effective are host-contact reduction methods in India?

PubMed

De Keyser, Rien; Cassidy, Clare; Laban, Swathi; Gopal, Prakash; Pickett, John A; Reddy, Yarabolu K; Prasad, Minakshi; Prasad, Gaya; Chirukandoth, Sreekumar; Senthilven, Kandasamy; Carpenter, Simon; Logan, James G

2017-01-31

Bluetongue virus (BTV) is transmitted by Culicoides biting midges and causes bluetongue (BT), a clinical disease observed primarily in sheep. BT has a detrimental effect on subsistence farmers in India, where hyperendemic outbreaks impact on smallholdings in the southern states of the country. In this study, we establish a reliable method for testing the toxic effects of deltamethrin on Culicoides and then compare deltamethrin with traditional control methods used by farmers in India. Effects of deltamethrin were initially tested using a colonised strain of Culicoides nubeculosus Meigen and a modified World Health Organisation exposure assay. This method was then applied to field populations of Culicoides spp. in India. The field population of C. oxystoma in India had a greater LC 50 (0.012 ± 0.009%) for deltamethrin than laboratory-reared C.nubeculosus (0.0013 ± 0.0002%). Exposure of C. nubeculosus to deltamethrin at higher ambient temperatures resulted in greater rates of knockdown but a lower mortality rate at 24 h post-exposure. Behavioural assays with C. nubeculosus in WHO tubes provided evidence for contact irritancy and spatial repellence caused by deltamethrin. The field experiments in India, however, provided no evidence for repellent or toxic effects of deltamethrin. Traditional methods such as the application of neem oil and burning of neem leaves also provided no protection. Our study demonstrates that field-collected Culicoides in India are less susceptible to deltamethrin exposure than laboratory-bred C. nubeculosus and traditional methods of insect control do not provide protection to sheep. These low levels of susceptibility to deltamethrin have not been recorded before in field populations of Culicoides and suggest resistance to synthetic pyrethrioids. Alternative insect control methods, in addition to vaccination, may be needed to protect Indian livestock from BTV transmission.

[Haptic tracking control for minimally invasive robotic surgery].

PubMed

Xu, Zhaohong; Song, Chengli; Wu, Wenwu

2012-06-01

Haptic feedback plays a significant role in minimally invasive robotic surgery (MIRS). A major deficiency of the current MIRS is the lack of haptic perception for the surgeon, including the commercially available robot da Vinci surgical system. In this paper, a dynamics model of a haptic robot is established based on Newton-Euler method. Because it took some period of time in exact dynamics solution, we used a digital PID arithmetic dependent on robot dynamics to ensure real-time bilateral control, and it could improve tracking precision and real-time control efficiency. To prove the proposed method, an experimental system in which two Novint Falcon haptic devices acting as master-slave system has been developed. Simulations and experiments showed proposed methods could give instrument force feedbacks to operator, and bilateral control strategy is an effective method to master-slave MIRS. The proposed methods could be used to tele-robotic system.

E-learning: controlling costs and increasing value.

PubMed

Walsh, Kieran

2015-04-01

E-learning now accounts for a substantial proportion of medical education provision. This progress has required significant investment and this investment has in turn come under increasing scrutiny so that the costs of e-learning may be controlled and its returns maximised. There are multiple methods by which the costs of e-learning can be controlled and its returns maximised. This short paper reviews some of those methods that are likely to be most effective and that are likely to save costs without compromising quality. Methods might include accessing free or low-cost resources from elsewhere; create short learning resources that will work on multiple devices; using open source platforms to host content; using in-house faculty to create content; sharing resources between institutions; and promoting resources to ensure high usage. Whatever methods are used to control costs or increase value, it is most important to evaluate the impact of these methods.

Coordination of fractional-order nonlinear multi-agent systems via distributed impulsive control

NASA Astrophysics Data System (ADS)

Ma, Tiedong; Li, Teng; Cui, Bing

2018-01-01

The coordination of fractional-order nonlinear multi-agent systems via distributed impulsive control method is studied in this paper. Based on the theory of impulsive differential equations, algebraic graph theory, Lyapunov stability theory and Mittag-Leffler function, two novel sufficient conditions for achieving the cooperative control of a class of fractional-order nonlinear multi-agent systems are derived. Finally, two numerical simulations are verified to illustrate the effectiveness and feasibility of the proposed method.

A nonlinear control method based on ANFIS and multiple models for a class of SISO nonlinear systems and its application.

PubMed

Zhang, Yajun; Chai, Tianyou; Wang, Hong

2011-11-01

This paper presents a novel nonlinear control strategy for a class of uncertain single-input and single-output discrete-time nonlinear systems with unstable zero-dynamics. The proposed method combines adaptive-network-based fuzzy inference system (ANFIS) with multiple models, where a linear robust controller, an ANFIS-based nonlinear controller and a switching mechanism are integrated using multiple models technique. It has been shown that the linear controller can ensure the boundedness of the input and output signals and the nonlinear controller can improve the dynamic performance of the closed loop system. Moreover, it has also been shown that the use of the switching mechanism can simultaneously guarantee the closed loop stability and improve its performance. As a result, the controller has the following three outstanding features compared with existing control strategies. First, this method relaxes the assumption of commonly-used uniform boundedness on the unmodeled dynamics and thus enhances its applicability. Second, since ANFIS is used to estimate and compensate the effect caused by the unmodeled dynamics, the convergence rate of neural network learning has been increased. Third, a "one-to-one mapping" technique is adapted to guarantee the universal approximation property of ANFIS. The proposed controller is applied to a numerical example and a pulverizing process of an alumina sintering system, respectively, where its effectiveness has been justified.

Air Pollution Translations: A Bibliography with Abstracts - Volume 2.

ERIC Educational Resources Information Center

National Air Pollution Control Administration (DHEW), Raleigh, NC.

This volume is the second in a series of compilations presenting abstracts and indexes of translations of technical air pollution literature. The 444 entries are grouped into 12 subject categories: General; Emission Sources; Atmospheric Interaction; Measurement Methods; Control Methods; Effects--Human Health; Effects--Plants and Livestock;…

Self-Explanation in the Domain of Statistics: An Expertise Reversal Effect

ERIC Educational Resources Information Center

Leppink, Jimmie; Broers, Nick J.; Imbos, Tjaart; van der Vleuten, Cees P. M.; Berger, Martijn P. F.

2012-01-01

This study investigated the effects of four instructional methods on cognitive load, propositional knowledge, and conceptual understanding of statistics, for low prior knowledge students and for high prior knowledge students. The instructional methods were (1) a reading-only control condition, (2) answering open-ended questions, (3) answering…

Controls on project proponents and environmental impact assessment effectiveness

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

Ortolano, L.

The degree of effectiveness of environmental impact assessment (EIA) for particular projects is associated with the existence of mechanisms of organizational control. Five dimensions of EIA effectiveness are considered: procedural compliance, completeness of EIA documents, methods to assess impacts, influence on project decisions, and weight given to environmental factors. Six mechanisms of control are introduced and illustrated by programs and projects in several countries. Experience in the Philippines under President Marcos demonstrates that procedural control in the form of EIA regulations, when used without other control mechanisms, will lead at most to token compliance. Judicial control, as practiced in themore » US, yields high procedural compliance. Evaluative control can yield effective EIA, but some systems based on this form of control treat only a small fraction of the major projects proposed. Both control exerted by development assistance organizations and control by professionals have great potential for yielding effective EIA, but that potential has not been fully realized. Control exerted directly by citizens or agencies not otherwise involved in EIA is uncommon, but cases from Taiwan demonstrate that those controls can be significant. An understanding of relationships between control mechanisms and EIA effectiveness is useful in designing EIA policies and programs.« less

Control research in the NASA high-alpha technology program

NASA Technical Reports Server (NTRS)

Gilbert, William P.; Nguyen, Luat T.; Gera, Joseph

1990-01-01

NASA is conducting a focused technology program, known as the High-Angle-of-Attack Technology Program, to accelerate the development of flight-validated technology applicable to the design of fighters with superior stall and post-stall characteristics and agility. A carefully integrated effort is underway combining wind tunnel testing, analytical predictions, piloted simulation, and full-scale flight research. A modified F-18 aircraft has been extensively instrumented for use as the NASA High-Angle-of-Attack Research Vehicle used for flight verification of new methods and concepts. This program stresses the importance of providing improved aircraft control capabilities both by powered control (such as thrust-vectoring) and by innovative aerodynamic control concepts. The program is accomplishing extensive coordinated ground and flight testing to assess and improve available experimental and analytical methods and to develop new concepts for enhanced aerodynamics and for effective control, guidance, and cockpit displays essential for effective pilot utilization of the increased agility provided.

A lattice hydrodynamic model based on delayed feedback control considering the effect of flow rate difference

NASA Astrophysics Data System (ADS)

Wang, Yunong; Cheng, Rongjun; Ge, Hongxia

2017-08-01

In this paper, a lattice hydrodynamic model is derived considering not only the effect of flow rate difference but also the delayed feedback control signal which including more comprehensive information. The control method is used to analyze the stability of the model. Furthermore, the critical condition for the linear steady traffic flow is deduced and the numerical simulation is carried out to investigate the advantage of the proposed model with and without the effect of flow rate difference and the control signal. The results are consistent with the theoretical analysis correspondingly.

Formation Control for Water-Jet USV Based on Bio-Inspired Method

NASA Astrophysics Data System (ADS)

Fu, Ming-yu; Wang, Duan-song; Wang, Cheng-long

2018-03-01

The formation control problem for underactuated unmanned surface vehicles (USVs) is addressed by a distributed strategy based on virtual leader strategy. The control system takes account of disturbance induced by external environment. With the coordinate transformation, the advantage of the proposed scheme is that the control point can be any point of the ship instead of the center of gravity. By introducing bio-inspired model, the formation control problem is addressed with backstepping method. This avoids complicated computation, simplifies the control law, and smoothes the input signals. The system uniform ultimate boundness is proven by Lyapunov stability theory with Young inequality. Simulation results are presented to verify the effectiveness and robust of the proposed controller.

Neuro-adaptive backstepping control of SISO non-affine systems with unknown gain sign.

PubMed

Ramezani, Zahra; Arefi, Mohammad Mehdi; Zargarzadeh, Hassan; Jahed-Motlagh, Mohammad Reza

2016-11-01

This paper presents two neuro-adaptive controllers for a class of uncertain single-input, single-output (SISO) nonlinear non-affine systems with unknown gain sign. The first approach is state feedback controller, so that a neuro-adaptive state-feedback controller is constructed based on the backstepping technique. The second approach is an observer-based controller and K-filters are designed to estimate the system states. The proposed method relaxes a priori knowledge of control gain sign and therefore by utilizing the Nussbaum-type functions this problem is addressed. In these methods, neural networks are employed to approximate the unknown nonlinear functions. The proposed adaptive control schemes guarantee that all the closed-loop signals are semi-globally uniformly ultimately bounded (SGUUB). Finally, the theoretical results are numerically verified through simulation examples. Simulation results show the effectiveness of the proposed methods. Copyright © 2016 ISA. All rights reserved.

Amplitude control of the track-induced self-excited vibration for a maglev system.

PubMed

Zhou, Danfeng; Li, Jie; Zhang, Kun

2014-09-01

The Electromagnet Suspension (EMS) maglev train uses controlled electromagnetic forces to achieve suspension, and self-excited vibration may occur due to the flexibility of the track. In this article, the harmonic balance method is applied to investigate the amplitude of the self-excited vibration, and it is found that the amplitude of the vibration depends on the voltage of the power supplier. Based on this observation, a vibration amplitude control method, which controls the amplitude of the vibration by adjusting the voltage of the power supplier, is proposed to attenuate the vibration. A PI controller is designed to control the amplitude of the vibration at a given level. The effectiveness of this method shows a good prospect for its application to commercial maglev systems. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Fault tolerant control laws

NASA Technical Reports Server (NTRS)

Ly, U. L.; Ho, J. K.

1986-01-01

A systematic procedure for the synthesis of fault tolerant control laws to actuator failure has been presented. Two design methods were used to synthesize fault tolerant controllers: the conventional LQ design method and a direct feedback controller design method SANDY. The latter method is used primarily to streamline the full-state Q feedback design into a practical implementable output feedback controller structure. To achieve robustness to control actuator failure, the redundant surfaces are properly balanced according to their control effectiveness. A simple gain schedule based on the landing gear up/down logic involving only three gains was developed to handle three design flight conditions: Mach .25 and Mach .60 at 5000 ft and Mach .90 at 20,000 ft. The fault tolerant control law developed in this study provides good stability augmentation and performance for the relaxed static stability aircraft. The augmented aircraft responses are found to be invariant to the presence of a failure. Furthermore, single-loop stability margins of +6 dB in gain and +30 deg in phase were achieved along with -40 dB/decade rolloff at high frequency.

Morphological alterations in the synganglion and integument of Rhipicephalus sanguineus ticks exposed to aqueous extracts of neem leaves (Azadirachta indica A. JUSS).

PubMed

Remedio, R N; Nunes, P H; Anholeto, L A; Camargo-Mathias, M I

2014-12-01

Currently, the necessity of controlling infestation by ticks, especially by Rhipicephalus sanguineus, has led researchers and public health managers around the world to search for new and more efficient control methods. This way, we can highlight neem (Azadirachta indica A. Juss) leaf, bark, and seed extracts, which have been very effective on tick control, and moreover causing less damage to the environment and to the host. This study showed the potential of neem as a control method for R. sanguineus through morphological and morphometric evaluation of the integument and synganglion of females, in semiengorged stage. To attain this, routine techniques of optical microscopy, scanning electron microscopy and morphometry of the cuticle and subcuticle of the integument were applied. Expressive morphological alterations were observed in both organs, presenting a dose-dependent effect. Integument epithelial cells and nerve cells of the synganglion showed signs of cell vacuolation, dilated intercellular boundaries, and cellular disorganization, alterations not previously reported in studies with neem. In addition, variations in subcuticle thickness were also observed. In general, the effects of neem are multiple, and affect the morphology and physiology of target animals in various ways. The results presented in this work are the first evidence of its effects in the coating and nervous system of ticks, thus allowing an indication of neem aqueous extracts as a potential control method of the brown dog tick and opening new perspectives on acaricide use. © 2014 Wiley Periodicals, Inc.

Simulation of traffic control signal systems

NASA Technical Reports Server (NTRS)

Connolly, P. J.; Concannon, P. A.; Ricci, R. C.

1974-01-01

In recent years there has been considerable interest in the development and testing of control strategies for networks of urban traffic signal systems by simulation. Simulation is an inexpensive and timely method for evaluating the effect of these traffic control strategies since traffic phenomena are too complex to be defined by analytical models and since a controlled experiment may be hazardous, expensive, and slow in producing meaningful results. This paper describes the application of an urban traffic corridor program, to evaluate the effectiveness of different traffic control strategies for the Massachusetts Avenue TOPICS Project.

Experimental study of flow separation control on a low- Re airfoil using leading-edge protuberance method

NASA Astrophysics Data System (ADS)

Zhang, M. M.; Wang, G. F.; Xu, J. Z.

2014-04-01

An experimental study of flow separation control on a low- Re c airfoil was presently investigated using a newly developed leading-edge protuberance method, motivated by the improvement in the hydrodynamics of the giant humpback whale through its pectoral flippers. Deploying this method, the control effectiveness of the airfoil aerodynamics was fully evaluated using a three-component force balance, leading to an effectively impaired stall phenomenon and great improvement in the performances within the wide post-stall angle range (22°-80°). To understand the flow physics behind, the vorticity field, velocity field and boundary layer flow field over the airfoil suction side were examined using a particle image velocimetry and an oil-flow surface visualization system. It was found that the leading-edge protuberance method, more like low-profile vortex generator, effectively modified the flow pattern of the airfoil boundary layer through the chordwise and spanwise evolutions of the interacting streamwise vortices generated by protuberances, where the separation of the turbulent boundary layer dominated within the stall region and the rather strong attachment of the laminar boundary layer still existed within the post-stall region. The characteristics to manipulate the flow separation mode of the original airfoil indicated the possibility to further optimize the control performance by reasonably designing the layout of the protuberances.

Economic evaluations of tobacco control mass media campaigns: a systematic review

PubMed Central

Atusingwize, Edwinah; Lewis, Sarah; Langley, Tessa

2015-01-01

Background International evidence shows that mass media campaigns are effective tobacco control interventions. However, they require substantial investment; a key question is whether their costs are justified by their benefits. The aim of this study was to systematically and comprehensively review economic evaluations of tobacco control mass media campaigns. Methods An electronic search of databases and grey literature was conducted to identify all published economic evaluations of tobacco control mass media campaigns. The authors reviewed studies independently and assessed the quality of studies using the Drummond 10-point checklist. A narrative synthesis was used to summarise the key features and quality of the identified studies. Results 10 studies met the inclusion criteria and were included in the review. All the studies included a cost effectiveness analysis, a cost utility analysis or both. The methods were highly heterogeneous, particularly in terms of the types of costs included. On the whole, studies were well conducted, but the interventions were often poorly described in terms of campaign content and intensity, and cost information was frequently inadequate. All studies concluded that tobacco control mass media campaigns are a cost effective public health intervention. Conclusions The evidence on the cost effectiveness of tobacco control mass media campaigns is limited, but of acceptable quality and consistently suggests that they offer good value for money. PMID:24985730

A Novel Hybrid Error Criterion-Based Active Control Method for on-Line Milling Vibration Suppression with Piezoelectric Actuators and Sensors

PubMed Central

Zhang, Xingwu; Wang, Chenxi; Gao, Robert X.; Yan, Ruqiang; Chen, Xuefeng; Wang, Shibin

2016-01-01

Milling vibration is one of the most serious factors affecting machining quality and precision. In this paper a novel hybrid error criterion-based frequency-domain LMS active control method is constructed and used for vibration suppression of milling processes by piezoelectric actuators and sensors, in which only one Fast Fourier Transform (FFT) is used and no Inverse Fast Fourier Transform (IFFT) is involved. The correction formulas are derived by a steepest descent procedure and the control parameters are analyzed and optimized. Then, a novel hybrid error criterion is constructed to improve the adaptability, reliability and anti-interference ability of the constructed control algorithm. Finally, based on piezoelectric actuators and acceleration sensors, a simulation of a spindle and a milling process experiment are presented to verify the proposed method. Besides, a protection program is added in the control flow to enhance the reliability of the control method in applications. The simulation and experiment results indicate that the proposed method is an effective and reliable way for on-line vibration suppression, and the machining quality can be obviously improved. PMID:26751448

A new model predictive control algorithm by reducing the computing time of cost function minimization for NPC inverter in three-phase power grids.

PubMed

Taheri, Asghar; Zhalebaghi, Mohammad Hadi

2017-11-01

This paper presents a new control strategy based on finite-control-set model-predictive control (FCS-MPC) for Neutral-point-clamped (NPC) three-level converters. Containing some advantages like fast dynamic response, easy inclusion of constraints and simple control loop, makes the FCS-MPC method attractive to use as a switching strategy for converters. However, the large amount of required calculations is a problem in the widespread of this method. In this way, to resolve this problem this paper presents a modified method that effectively reduces the computation load compare with conventional FCS-MPC method and at the same time does not affect on control performance. The proposed method can be used for exchanging power between electrical grid and DC resources by providing active and reactive power compensations. Experiments on three-level converter for three Power Factor Correction (PFC), inductive and capacitive compensation modes verify the good and comparable performance. The results have been simulated using MATLAB/SIMULINK software. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Effect of sampling rate and record length on the determination of stability and control derivatives

NASA Technical Reports Server (NTRS)

Brenner, M. J.; Iliff, K. W.; Whitman, R. K.

1978-01-01

Flight data from five aircraft were used to assess the effects of sampling rate and record length reductions on estimates of stability and control derivatives produced by a maximum likelihood estimation method. Derivatives could be extracted from flight data with the maximum likelihood estimation method even if there were considerable reductions in sampling rate and/or record length. Small amplitude pulse maneuvers showed greater degradation of the derivative maneuvers than large amplitude pulse maneuvers when these reductions were made. Reducing the sampling rate was found to be more desirable than reducing the record length as a method of lessening the total computation time required without greatly degrading the quantity of the estimates.

Simple, Low-Cost Data Collection Methods for Agricultural Field Studies.

ERIC Educational Resources Information Center

Koenig, Richard T.; Winger, Marlon; Kitchen, Boyd

2000-01-01

Summarizes relatively simple and inexpensive methods for collecting data from agricultural field studies. Describes methods involving on-farm testing, crop yield measurement, quality evaluations, weed control effectiveness, plant nutrient status, and other measures. Contains 29 references illustrating how these methods were used to conduct…

Surface contouring by controlled application of processing fluid using Marangoni effect

DOEpatents

Rushford, Michael C.; Britten, Jerald A.

2003-04-29

An apparatus and method for modifying the surface of an object by contacting said surface with a liquid processing solution using the liquid applicator geometry and Marangoni effect (surface tension gradient-driven flow) to define and confine the dimensions of the wetted zone on said object surface. In particular, the method and apparatus involve contouring or figuring the surface of an object using an etchant solution as the wetting fluid and using realtime metrology (e.g. interferometry) to control the placement and dwell time of this wetted zone locally on the surface of said object, thereby removing material from the surface of the object in a controlled manner. One demonstrated manifestation is in the deterministic optical figuring of thin glasses by wet chemical etching using a buffered hydrofluoric acid solution and Marangoni effect.

The Application of Auto-Disturbance Rejection Control Optimized by Least Squares Support Vector Machines Method and Time-Frequency Representation in Voltage Source Converter-High Voltage Direct Current System.

PubMed

Liu, Ying-Pei; Liang, Hai-Ping; Gao, Zhong-Ke

2015-01-01

In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles. We ignore the tracking differentiator in the ADRC controller aiming to improve the system dynamic response speed. On this basis, we derive the mathematical model of ADRC controller optimized by LSSVM for direct current voltage loop. Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method. In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD) and adaptive optimal kernel (AOK) time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane.

The Application of Auto-Disturbance Rejection Control Optimized by Least Squares Support Vector Machines Method and Time-Frequency Representation in Voltage Source Converter-High Voltage Direct Current System

PubMed Central

Gao, Zhong-Ke

2015-01-01

In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles. We ignore the tracking differentiator in the ADRC controller aiming to improve the system dynamic response speed. On this basis, we derive the mathematical model of ADRC controller optimized by LSSVM for direct current voltage loop. Finally we carry out simulations to verify the feasibility and effectiveness of our proposed control method. In addition, we employ the time-frequency representation methods, i.e., Wigner-Ville distribution (WVD) and adaptive optimal kernel (AOK) time-frequency representation, to demonstrate our proposed method performs better than the traditional method from the perspective of energy distribution in time and frequency plane. PMID:26098556

The potential impact of integrated malaria transmission control on entomologic inoculation rate in highly endemic areas.

PubMed

Killeen, G F; McKenzie, F E; Foy, B D; Schieffelin, C; Billingsley, P F; Beier, J C

2000-05-01

We have used a relatively simple but accurate model for predicting the impact of integrated transmission control on the malaria entomologic inoculation rate (EIR) at four endemic sites from across sub-Saharan Africa and the southwest Pacific. The simulated campaign incorporated modestly effective vaccine coverage, bed net use, and larval control. The results indicate that such campaigns would reduce EIRs at all four sites by 30- to 50-fold. Even without the vaccine, 15- to 25-fold reductions of EIR were predicted, implying that integrated control with a few modestly effective tools can meaningfully reduce malaria transmission in a range of endemic settings. The model accurately predicts the effects of bed nets and indoor spraying and demonstrates that they are the most effective tools available for reducing EIR. However, the impact of domestic adult vector control is amplified by measures for reducing the rate of emergence of vectors or the level of infectiousness of the human reservoir. We conclude that available tools, including currently neglected methods for larval control, can reduce malaria transmission intensity enough to alleviate mortality. Integrated control programs should be implemented to the fullest extent possible, even in areas of intense transmission, using simple models as decision-making tools. However, we also conclude that to eliminate malaria in many areas of intense transmission is beyond the scope of methods which developing nations can currently afford. New, cost-effective, practical tools are needed if malaria is ever to be eliminated from highly endemic areas.

On the effect of local barrier height in scanning tunneling microscopy: Measurement methods and control implications

NASA Astrophysics Data System (ADS)

Tajaddodianfar, Farid; Moheimani, S. O. Reza; Owen, James; Randall, John N.

2018-01-01

A common cause of tip-sample crashes in a Scanning Tunneling Microscope (STM) operating in constant current mode is the poor performance of its feedback control system. We show that there is a direct link between the Local Barrier Height (LBH) and robustness of the feedback control loop. A method known as the "gap modulation method" was proposed in the early STM studies for estimating the LBH. We show that the obtained measurements are affected by controller parameters and propose an alternative method which we prove to produce LBH measurements independent of the controller dynamics. We use the obtained LBH estimation to continuously update the gains of a STM proportional-integral (PI) controller and show that while tuning the PI gains, the closed-loop system tolerates larger variations of LBH without experiencing instability. We report experimental results, conducted on two STM scanners, to establish the efficiency of the proposed PI tuning approach. Improved feedback stability is believed to help in avoiding the tip/sample crash in STMs.

Optimum vibration control of flexible beams by piezo-electric actuators

NASA Technical Reports Server (NTRS)

Baz, A.; Poh, S.; Studer, P.

1988-01-01

The utilization of piezoelectric actuators in controlling the structural vibrations of flexible beams is examined. A Modified Independent Modal Space Control (MIMSC) method is devised to enable the selection of the optimal location, control gains and excitation voltage of the piezoelectric actuators in a way that would minimize the amplitudes of vibrations of beams to which these actuators are bonded, as well as the input control energy necessary to suppress these vibrations. The developed method accounts for the effects that the piezoelectric actuators have on changing the elastic and inertial properties of the flexible beams. Numerical examples are presented to illustrate the application of the developed MIMSC method in minimizing the structural vibrations of beams of different materials when subjected to different loading and end conditions using ceramic or polymeric piezoelectric actuators. The obtained results emphasize the importance of the devised method in designing more realistic active control systems for flexible beams, in particular, and large flexible structures in general.

Optimum vibration control of flexible beams by piezo-electric actuators

NASA Technical Reports Server (NTRS)

Baz, A.; Poh, S.

1987-01-01

The utilization of piezoelectric actuators in controlling the structural vibrations of flexible beams is examined. A Modified Independent Modal Space Control (MIMSC) method is devised to enable the selection of the optimal location, control gains and excitation voltage of the piezoelectric actuators in a way that would minimize the amplitudes of vibrations of beams to which these actuators are bonded, as well as the input control energy necessary to suppress these vibrations. The developed method accounts for the effects that the piezoelectric actuators have on changing the elastic and inertial properties of the flexible beams. Numerical examples are presented to illustrate the application of the developed MIMSC method in minimizing the structural vibrations of beams of different materials when subjected to different loading and end conditions using ceramic or polymeric piezoelectric actuators. The obtained results emphasize the importance of the devised method in designing more realistic active control systems for flexible beams, in particular, and large flexible structures in general.

A Two-Time Scale Decentralized Model Predictive Controller Based on Input and Output Model

PubMed Central

Niu, Jian; Zhao, Jun; Xu, Zuhua; Qian, Jixin

2009-01-01

A decentralized model predictive controller applicable for some systems which exhibit different dynamic characteristics in different channels was presented in this paper. These systems can be regarded as combinations of a fast model and a slow model, the response speeds of which are in two-time scale. Because most practical models used for control are obtained in the form of transfer function matrix by plant tests, a singular perturbation method was firstly used to separate the original transfer function matrix into two models in two-time scale. Then a decentralized model predictive controller was designed based on the two models derived from the original system. And the stability of the control method was proved. Simulations showed that the method was effective. PMID:19834542

Adaptive neural control for a class of nonlinear time-varying delay systems with unknown hysteresis.

PubMed

Liu, Zhi; Lai, Guanyu; Zhang, Yun; Chen, Xin; Chen, Chun Lung Philip

2014-12-01

This paper investigates the fusion of unknown direction hysteresis model with adaptive neural control techniques in face of time-delayed continuous time nonlinear systems without strict-feedback form. Compared with previous works on the hysteresis phenomenon, the direction of the modified Bouc-Wen hysteresis model investigated in the literature is unknown. To reduce the computation burden in adaptation mechanism, an optimized adaptation method is successfully applied to the control design. Based on the Lyapunov-Krasovskii method, two neural-network-based adaptive control algorithms are constructed to guarantee that all the system states and adaptive parameters remain bounded, and the tracking error converges to an adjustable neighborhood of the origin. In final, some numerical examples are provided to validate the effectiveness of the proposed control methods.

The Effectiveness of Healthy Start Home Visit Program: Cluster Randomized Controlled Trial

ERIC Educational Resources Information Center

Leung, Cynthia; Tsang, Sandra; Heung, Kitty

2015-01-01

Purpose: The study reported the effectiveness of a home visit program for disadvantaged Chinese parents with preschool children, using cluster randomized controlled trial design. Method: Participants included 191 parents and their children from 24 preschools, with 84 dyads (12 preschools) in the intervention group and 107 dyads (12 preschools) in…

Pesticides, A Scientists' Institute for Public Information Workbook.

ERIC Educational Resources Information Center

Dahlsten, Donald L.; And Others

This collection of articles emphasizes the need for care in the use of chemical pesticides. Economic and ecological implications of pest control are discussed, and data are given on the effectiveness and side effects of chemical insecticides. Alternative methods of control are proposed. The part that can be played by the public in decision making…

Effectiveness of Solution-Focused Brief Therapy: A Systematic Qualitative Review of Controlled Outcome Studies

ERIC Educational Resources Information Center

Gingerich, Wallace J.; Peterson, Lance T.

2013-01-01

Objective: We review all available controlled outcome studies of solution-focused brief therapy (SFBT) to evaluate evidence of its effectiveness. Method: Forty-three studies were located and key data abstracted on problem, setting, SFBT intervention, design characteristics, and outcomes. Results: Thirty-two (74%) of the studies reported…

Reading and Language Intervention for Children at Risk of Dyslexia: A Randomised Controlled Trial

ERIC Educational Resources Information Center

Duff, Fiona J.; Hulme, Charles; Grainger, Katy; Hardwick, Samantha J.; Miles, Jeremy N. V.; Snowling, Margaret J.

2014-01-01

Background: Intervention studies for children at risk of dyslexia have typically been delivered preschool, and show short-term effects on letter knowledge and phoneme awareness, with little transfer to literacy. Methods: This randomised controlled trial evaluated the effectiveness of a reading and language intervention for 6-year-old children…

Effects of solar activity in the middle atmosphere dynamical regime over Eastern Siberia, USSR

NASA Technical Reports Server (NTRS)

Gaidukov, V. A.; Kazimirovsky, E. S.; Zhovty, E. I.; Chernigovskaya, M. A.

1989-01-01

Lower thermospheric (90 to 120 km) wind data was acquired by ground based spaced-receiver method (HF, LF) near Irkutsk (52 deg N, 104 deg E). There is interrelated solar and meteorological control of lower thermosphere dynamics. Some features of solar control effects on the wind parameters are discussed.

Crested wheatgrass control and native plant establishment in Utah

Treesearch

April Hulet; Bruce A. Roundy; Brad Jessop

2010-01-01

Effective control methods need to be developed to reduce crested wheatgrass (Agropyron cristatum [L.] Gaertner) monocultures and promote the establishment of native species. This research was designed to determine effective ways to reduce crested wheatgrass and establish native species while minimizing weed invasion. We mechanically (single- or double-pass disking) and...

The Effects of Variations in Lesson Control and Practice on Learning from Interactive Video.

ERIC Educational Resources Information Center

Hannafin, Michael J.; Colamaio, MaryAnne E.

1987-01-01

Discussion of the effects of variations in lesson control and practice on the learning of facts, procedures, and problem-solving skills during interactive video instruction focuses on a study of graduates and advanced level undergraduates learning cardiopulmonary resuscitation (CPR). Embedded questioning methods and posttests used are described.…

Myopia Control: A Review.

PubMed

Walline, Jeffrey J

2016-01-01

Slowing the progression of myopia has become a considerable concern for parents of myopic children. At the same time, clinical science is rapidly advancing the knowledge about methods to slow myopia progression. This article reviews the peer-reviewed literature regarding several modalities attempting to control myopia progression. Several strategies have been shown to be ineffective for myopia control, including undercorrection of myopic refractive error, alignment fit gas-permeable contact lenses, outdoor time, and bifocal of multifocal spectacles. However, a recent randomized clinical trial fitted progressing myopic children with executive bifocals for 3 years and found a 39% slowing of myopia progression for bifocal-only spectacles and 50% treatment effect for bifocal spectacles with base-in prism, although there was not a significant difference in progression between the bifocal-only and bifocal plus prism groups. Interestingly, outdoor time has shown to be effective for reducing the onset of myopia but not for slowing the progression of myopic refractive error. More effective methods of myopia control include orthokeratology, soft bifocal contact lenses, and antimuscarinic agents. Orthokeratology and soft bifocal contact lenses are both thought to provide myopic blur to the retina, which acts as a putative cue to slow myopic eye growth. Each of these myopia control methods provides, on average, slightly less than 50% slowing of myopia progression. All studies have shown clinically meaningful slowing of myopia progression, including several randomized clinical trials. The most investigated antimuscarinic agents include pirenzepine and atropine. Pirenzepine slows myopia progression by approximately 40%, but it is not commercially available in the United States. Atropine provides the best myopia control, but the cycloplegic and mydriatic side effects render it a rarely prescribed myopia control agent in the United States. However, low-concentration atropine has been shown to provide effective myopia control with far fewer side effects than 1.0% atropine. Finally, two agents, low-concentration atropine and outdoor time have been shown to reduce the likelihood of myopia onset. Over the past few years, much has been learned about how to slow the progression of nearsightedness in children, but we still have a lot to learn.

NASA Iced Aerodynamics and Controls Current Research

NASA Technical Reports Server (NTRS)

Addy, Gene

2009-01-01

This slide presentation reviews the state of current research in the area of aerodynamics and aircraft control with ice conditions by the Aviation Safety Program, part of the Integrated Resilient Aircraft Controls Project (IRAC). Included in the presentation is a overview of the modeling efforts. The objective of the modeling is to develop experimental and computational methods to model and predict aircraft response during adverse flight conditions, including icing. The Aircraft icing modeling efforts includes the Ice-Contaminated Aerodynamics Modeling, which examines the effects of ice contamination on aircraft aerodynamics, and CFD modeling of ice-contaminated aircraft aerodynamics, and Advanced Ice Accretion Process Modeling which examines the physics of ice accretion, and works on computational modeling of ice accretions. The IRAC testbed, a Generic Transport Model (GTM) and its use in the investigation of the effects of icing on its aerodynamics is also reviewed. This has led to a more thorough understanding and models, both theoretical and empirical of icing physics and ice accretion for airframes, advanced 3D ice accretion prediction codes, CFD methods for iced aerodynamics and better understanding of aircraft iced aerodynamics and its effects on control surface effectiveness.

Computationally efficient control allocation

NASA Technical Reports Server (NTRS)

Durham, Wayne (Inventor)

2001-01-01

A computationally efficient method for calculating near-optimal solutions to the three-objective, linear control allocation problem is disclosed. The control allocation problem is that of distributing the effort of redundant control effectors to achieve some desired set of objectives. The problem is deemed linear if control effectiveness is affine with respect to the individual control effectors. The optimal solution is that which exploits the collective maximum capability of the effectors within their individual physical limits. Computational efficiency is measured by the number of floating-point operations required for solution. The method presented returned optimal solutions in more than 90% of the cases examined; non-optimal solutions returned by the method were typically much less than 1% different from optimal and the errors tended to become smaller than 0.01% as the number of controls was increased. The magnitude of the errors returned by the present method was much smaller than those that resulted from either pseudo inverse or cascaded generalized inverse solutions. The computational complexity of the method presented varied linearly with increasing numbers of controls; the number of required floating point operations increased from 5.5 i, to seven times faster than did the minimum-norm solution (the pseudoinverse), and at about the same rate as did the cascaded generalized inverse solution. The computational requirements of the method presented were much better than that of previously described facet-searching methods which increase in proportion to the square of the number of controls.

Separation Control at Flight Reynolds Numbers: Lessons Learned and Future Directions

NASA Technical Reports Server (NTRS)

Pack, LaTunia G.; Seifert, Avi

2000-01-01

Active separation control, using periodic excitation, was studied experimentally at high Reynolds numbers. The effects of compressibility, mild sweep, location of excitation slot and steady momentum transfer on the efficacy of the method were identified. Tests conducted at chord Reynolds numbers as high as 40 x 10(exp 6) demonstrated that active control using oscillatory flow excitation can effectively delay flow separation from, and reattach separated flow to aerodynamic surfaces at flight conditions. The effective frequencies generate one to four vortices over the controlled region at all times, regardless of the Reynolds number. The vortices are initially amplified by the separated shear-layer, and after initiating reattachment, the strength of the vortices decay as they are convected downstream. Large amplitude, low frequency vortices break down to smaller ones upon introduction at the excitation slot. The effects of steady mass transfer were compared to those of periodic excitation. It was found that steady blowing is significantly inferior to periodic excitation in terms of performance benefits and that the response to steady blowing is abrupt, and therefore undesirable from a control point of view. Steady suction and periodic excitation are comparable in effectiveness and both exhibit a gradual response to changes in the magnitude of the control input. The combination of weak steady suction and periodic excitation is extremely effective while the addition of steady blowing could be detrimental. Compressibility effects are weak as long as separation is not caused by a shock-wave/boundary-layer interaction. The undesirable effects of the shock-induced separation could be alleviated by the introduction of periodic excitation upstream of the shock wave, inside the region of supersonic flow. The effects of mild sweep were also studied and periodic excitation was found to be very effective in reattaching three-dimensional separated flow. Scaling laws that correlate 2D and 3D controlled flows were tested and verified. Several performance benefits could be gained by applying the method to existing configurations, but it is expected that the full potential of the method can only be realized through the design of new configurations. A comprehensive, fully turbulent, database was generated in order to guide the development, and enable validation, of candidate unsteady CFD design tools.

Separation Control at Flight Reynolds Numbers: Lessons Learned and Future Directions

NASA Technical Reports Server (NTRS)

Seifert, Avi; Pack, LaTunia G.

2000-01-01

Active separation control, using periodic excitation, was studied experimentally at high Reynolds numbers. The effects of compressibility, mild sweep, location o excitation slot and steady momentum transfer on the efficacy of the method were identified. Tests conducted at chord Reynolds numbers as high as 40 x 10(exp 6) demonstrated that active control using oscillatory flow excitation can effectively delay flow separation from and reattach separated flow to aerodynamic surfaces at flight conditions. The effective frequencies generate one to four vortices over the controlled region at all times, regardless of the Reynolds number. The vortices are initially amplified by the separated shear-layer, and after initiating reattachment, the strength of the vortices decay as they are convected downstream. Large amplitude, low frequency vortices break down to smaller ones upon introduction at the excitation slot. The effects of steady mass transfer were compared to those of periodic excitation. It was found that steady blowing is significantly inferior to periodic excitation in terms o performance benefits and that the response to steady blowing is abrupt, and therefore undesirable from a control point of view. Steady suction and periodic excitation are comparable in effectiveness and both exhibit a gradual response to changes in the magnitude of the control input. The combination of weak steady suction and periodic excitation is extremely effective while the addition of steady blowing could be detrimental. Compressibility effects are weak as long as separation is not caused by a shock-wave/boundary-layer interaction The undesirable effects of the shock-induced separation could be alleviated by the introduction of periodic excitation upstream of the shock wave, inside the region of supersonic flow. The effects of mild sweep were also studied and periodic excitation was found to be very effective in reattaching three-dimensional separated flow. Scaling laws that correlate 2D and 3D controlled flows were tested and verified. Several performance benefits could be gained by applying the method to existing configurations, but it is expected that the full potential of the method can only be realized through the design of new configurations. A comprehensive, fully turbulent, database was generated in order to guide the development, and enable validation, of candidate unsteady CFD design tools.

Model-Free Optimal Tracking Control via Critic-Only Q-Learning.

PubMed

Luo, Biao; Liu, Derong; Huang, Tingwen; Wang, Ding

2016-10-01

Model-free control is an important and promising topic in control fields, which has attracted extensive attention in the past few years. In this paper, we aim to solve the model-free optimal tracking control problem of nonaffine nonlinear discrete-time systems. A critic-only Q-learning (CoQL) method is developed, which learns the optimal tracking control from real system data, and thus avoids solving the tracking Hamilton-Jacobi-Bellman equation. First, the Q-learning algorithm is proposed based on the augmented system, and its convergence is established. Using only one neural network for approximating the Q-function, the CoQL method is developed to implement the Q-learning algorithm. Furthermore, the convergence of the CoQL method is proved with the consideration of neural network approximation error. With the convergent Q-function obtained from the CoQL method, the adaptive optimal tracking control is designed based on the gradient descent scheme. Finally, the effectiveness of the developed CoQL method is demonstrated through simulation studies. The developed CoQL method learns with off-policy data and implements with a critic-only structure, thus it is easy to realize and overcome the inadequate exploration problem.

A case study of the relative effects of power plant nitrogen oxides and sulfur dioxide emission reductions on atmospheric nitrogen deposition.

PubMed

Vijayaraghavan, Krish; Seigneur, Christian; Bronson, Rochelle; Chen, Shu-Yun; Karamchandani, Prakash; Walters, Justin T; Jansen, John J; Brandmeyer, Jo Ellen; Knipping, Eladio M

2010-03-01

The contrasting effects of point source nitrogen oxides (NOx) and sulfur dioxide (SO2) air emission reductions on regional atmospheric nitrogen deposition are analyzed for the case study of a coal-fired power plant in the southeastern United States. The effect of potential emission reductions at the plant on nitrogen deposition to Escambia Bay and its watershed on the Florida-Alabama border is simulated using the three-dimensional Eulerian Community Multiscale Air Quality (CMAQ) model. A method to quantify the relative and individual effects of NOx versus SO2 controls on nitrogen deposition using air quality modeling results obtained from the simultaneous application of NOx and SO2 emission controls is presented and discussed using the results from CMAQ simulations conducted with NOx-only and SO2-only emission reductions; the method applies only to cases in which ambient inorganic nitrate is present mostly in the gas phase; that is, in the form of gaseous nitric acid (HNO3). In such instances, the individual effects of NOx and SO2 controls on nitrogen deposition can be approximated by the effects of combined NOx + SO2 controls on the deposition of NOy, (the sum of oxidized nitrogen species) and reduced nitrogen species (NHx), respectively. The benefit of controls at the plant in terms of the decrease in nitrogen deposition to Escambia Bay and watershed is less than 6% of the overall benefit due to regional Clean Air Interstate Rule (CAIR) controls.

The Long-Term Effectiveness of a Selective, Personality-Targeted Prevention Program in Reducing Alcohol Use and Related Harms: A Cluster Randomized Controlled Trial

ERIC Educational Resources Information Center

Newton, Nicola C.; Conrod, Patricia J.; Slade, Tim; Carragher, Natacha; Champion, Katrina E.; Barrett, Emma L.; Kelly, Erin V.; Nair, Natasha K.; Stapinski, Lexine; Teesson, Maree

2016-01-01

Background: This study investigated the long-term effectiveness of Preventure, a selective personality-targeted prevention program, in reducing the uptake of alcohol, harmful use of alcohol, and alcohol-related harms over a 3-year period. Methods: A cluster randomized controlled trial was conducted to assess the effectiveness of Preventure.…

Application of numerical optimization techniques to control system design for nonlinear dynamic models of aircraft

NASA Technical Reports Server (NTRS)

Lan, C. Edward; Ge, Fuying

1989-01-01

Control system design for general nonlinear flight dynamic models is considered through numerical simulation. The design is accomplished through a numerical optimizer coupled with analysis of flight dynamic equations. The general flight dynamic equations are numerically integrated and dynamic characteristics are then identified from the dynamic response. The design variables are determined iteratively by the optimizer to optimize a prescribed objective function which is related to desired dynamic characteristics. Generality of the method allows nonlinear effects to aerodynamics and dynamic coupling to be considered in the design process. To demonstrate the method, nonlinear simulation models for an F-5A and an F-16 configurations are used to design dampers to satisfy specifications on flying qualities and control systems to prevent departure. The results indicate that the present method is simple in formulation and effective in satisfying the design objectives.

Cascading failure in the wireless sensor scale-free networks

NASA Astrophysics Data System (ADS)

Liu, Hao-Ran; Dong, Ming-Ru; Yin, Rong-Rong; Han, Li

2015-05-01

In the practical wireless sensor networks (WSNs), the cascading failure caused by a failure node has serious impact on the network performance. In this paper, we deeply research the cascading failure of scale-free topology in WSNs. Firstly, a cascading failure model for scale-free topology in WSNs is studied. Through analyzing the influence of the node load on cascading failure, the critical load triggering large-scale cascading failure is obtained. Then based on the critical load, a control method for cascading failure is presented. In addition, the simulation experiments are performed to validate the effectiveness of the control method. The results show that the control method can effectively prevent cascading failure. Project supported by the Natural Science Foundation of Hebei Province, China (Grant No. F2014203239), the Autonomous Research Fund of Young Teacher in Yanshan University (Grant No. 14LGB017) and Yanshan University Doctoral Foundation, China (Grant No. B867).

The use of propensity score methods with survival or time-to-event outcomes: reporting measures of effect similar to those used in randomized experiments.

PubMed

Austin, Peter C

2014-03-30

Propensity score methods are increasingly being used to estimate causal treatment effects in observational studies. In medical and epidemiological studies, outcomes are frequently time-to-event in nature. Propensity-score methods are often applied incorrectly when estimating the effect of treatment on time-to-event outcomes. This article describes how two different propensity score methods (matching and inverse probability of treatment weighting) can be used to estimate the measures of effect that are frequently reported in randomized controlled trials: (i) marginal survival curves, which describe survival in the population if all subjects were treated or if all subjects were untreated; and (ii) marginal hazard ratios. The use of these propensity score methods allows one to replicate the measures of effect that are commonly reported in randomized controlled trials with time-to-event outcomes: both absolute and relative reductions in the probability of an event occurring can be determined. We also provide guidance on variable selection for the propensity score model, highlight methods for assessing the balance of baseline covariates between treated and untreated subjects, and describe the implementation of a sensitivity analysis to assess the effect of unmeasured confounding variables on the estimated treatment effect when outcomes are time-to-event in nature. The methods in the paper are illustrated by estimating the effect of discharge statin prescribing on the risk of death in a sample of patients hospitalized with acute myocardial infarction. In this tutorial article, we describe and illustrate all the steps necessary to conduct a comprehensive analysis of the effect of treatment on time-to-event outcomes. © 2013 The authors. Statistics in Medicine published by John Wiley & Sons, Ltd.

Determination of stability and control parameters of a light airplane from flight data using two estimation methods. [equation error and maximum likelihood methods

NASA Technical Reports Server (NTRS)

Klein, V.

1979-01-01

Two identification methods, the equation error method and the output error method, are used to estimate stability and control parameter values from flight data for a low-wing, single-engine, general aviation airplane. The estimated parameters from both methods are in very good agreement primarily because of sufficient accuracy of measured data. The estimated static parameters also agree with the results from steady flights. The effect of power different input forms are demonstrated. Examination of all results available gives the best values of estimated parameters and specifies their accuracies.

[Development of knowledge, attitude and practice questionnaire on prevention and control of occupational diseases].

PubMed

Gao, Yuan; Feng, Yuchao; Wang, Min; Su, Yiwei; Li, Yanhua; Wang, Zhi; Tang, Shihao

2015-04-01

To develop the knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for occupational groups, and to provide a convenient and effective tool for the survey of knowledge, attitude, and behavior on the prevention and control of occupational diseases in occupational groups and the evaluation of intervention effect. The initial questionnaire which was evaluated by the experts was used to carry out a pre-survey in Guangzhou, China. The survey results were statistically analyzed by t test, identification index method, correlation analysis, and Cronbach's a coefficient method. And then the questionnaire was further modified, and the content of the questionnaire was determined finally. After modification, there were 18 items on knowledge, 16 items on attitude, and 12 items on behavior in the "Knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for enterprise managers"; there were 19 items on knowledge, 10 items on attitude, and 11 items on behavior in the "Knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for workers". The knowledge, attitude and practice questionnaire on the prevention and control of occupational diseases for occupational groups is developed successfully, and it is a convenient and effective tool for the survey of knowledge, attitude, and behavior on the prevention and control of occupational diseases in occupational groups and the evaluation of intervention effect.

Estimation of effective wind speed

NASA Astrophysics Data System (ADS)

Østergaard, K. Z.; Brath, P.; Stoustrup, J.

2007-07-01

The wind speed has a huge impact on the dynamic response of wind turbine. Because of this, many control algorithms use a measure of the wind speed to increase performance, e.g. by gain scheduling and feed forward. Unfortunately, no accurate measurement of the effective wind speed is online available from direct measurements, which means that it must be estimated in order to make such control methods applicable in practice. In this paper a new method is presented for the estimation of the effective wind speed. First, the rotor speed and aerodynamic torque are estimated by a combined state and input observer. These two variables combined with the measured pitch angle is then used to calculate the effective wind speed by an inversion of a static aerodynamic model.

Bi-Objective Optimal Control Modification Adaptive Control for Systems with Input Uncertainty

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.

2012-01-01

This paper presents a new model-reference adaptive control method based on a bi-objective optimal control formulation for systems with input uncertainty. A parallel predictor model is constructed to relate the predictor error to the estimation error of the control effectiveness matrix. In this work, we develop an optimal control modification adaptive control approach that seeks to minimize a bi-objective linear quadratic cost function of both the tracking error norm and predictor error norm simultaneously. The resulting adaptive laws for the parametric uncertainty and control effectiveness uncertainty are dependent on both the tracking error and predictor error, while the adaptive laws for the feedback gain and command feedforward gain are only dependent on the tracking error. The optimal control modification term provides robustness to the adaptive laws naturally from the optimal control framework. Simulations demonstrate the effectiveness of the proposed adaptive control approach.

Bayesian analysis of multimethod ego-depletion studies favours the null hypothesis.

PubMed

Etherton, Joseph L; Osborne, Randall; Stephenson, Katelyn; Grace, Morgan; Jones, Chas; De Nadai, Alessandro S

2018-04-01

Ego-depletion refers to the purported decrease in performance on a task requiring self-control after engaging in a previous task involving self-control, with self-control proposed to be a limited resource. Despite many published studies consistent with this hypothesis, recurrent null findings within our laboratory and indications of publication bias have called into question the validity of the depletion effect. This project used three depletion protocols involved three different depleting initial tasks followed by three different self-control tasks as dependent measures (total n = 840). For each method, effect sizes were not significantly different from zero When data were aggregated across the three different methods and examined meta-analytically, the pooled effect size was not significantly different from zero (for all priors evaluated, Hedges' g = 0.10 with 95% credibility interval of [-0.05, 0.24]) and Bayes factors reflected strong support for the null hypothesis (Bayes factor > 25 for all priors evaluated). © 2018 The British Psychological Society.

Comparison of Cue-Controlled Desensitization, Rational Restructuring, and a Credible Placebo in the Treatment of Speech Anxiety.

ERIC Educational Resources Information Center

Lent, Robert W.; And Others

1981-01-01

The efficacy of cue-controlled desensitization and systematic rational restructuring was compared with a placebo method and a waiting-list control in reducing public speaking and nontargeted anxieties. Cue-controlled desensitization was generally more effective than the other groups in reducing subjective speech anxiety. (Author)

In-flight performance optimization for rotorcraft with redundant controls

NASA Astrophysics Data System (ADS)

Ozdemir, Gurbuz Taha

A conventional helicopter has limits on performance at high speeds because of the limitations of main rotor, such as compressibility issues on advancing side or stall issues on retreating side. Auxiliary lift and thrust components have been suggested to improve performance of the helicopter substantially by reducing the loading on the main rotor. Such a configuration is called the compound rotorcraft. Rotor speed can also be varied to improve helicopter performance. In addition to improved performance, compound rotorcraft and variable RPM can provide a much larger degree of control redundancy. This additional redundancy gives the opportunity to further enhance performance and handling qualities. A flight control system is designed to perform in-flight optimization of redundant control effectors on a compound rotorcraft in order to minimize power required and extend range. This "Fly to Optimal" (FTO) control law is tested in simulation using the GENHEL model. A model of the UH-60, a compound version of the UH-60A with lifting wing and vectored thrust ducted propeller (VTDP), and a generic compound version of the UH-60A with lifting wing and propeller were developed and tested in simulation. A model following dynamic inversion controller is implemented for inner loop control of roll, pitch, yaw, heave, and rotor RPM. An outer loop controller regulates airspeed and flight path during optimization. A Golden Section search method was used to find optimal rotor RPM on a conventional helicopter, where the single redundant control effector is rotor RPM. The FTO builds off of the Adaptive Performance Optimization (APO) method of Gilyard by performing low frequency sweeps on a redundant control for a fixed wing aircraft. A method based on the APO method was used to optimize trim on a compound rotorcraft with several redundant control effectors. The controller can be used to optimize rotor RPM and compound control effectors through flight test or simulations in order to establish a schedule. The method has been expanded to search a two-dimensional control space. Simulation results demonstrate the ability to maximize range by optimizing stabilator deflection and an airspeed set point. Another set of results minimize power required in high speed flight by optimizing collective pitch and stabilator deflection. Results show that the control laws effectively hold the flight condition while the FTO method is effective at improving performance. Optimizations show there can be issues when the control laws regulating altitude push the collective control towards it limits. So a modification was made to the control law to regulate airspeed and altitude using propeller pitch and angle of attack while the collective is held fixed or used as an optimization variable. A dynamic trim limit avoidance algorithm is applied to avoid control saturation in other axes during optimization maneuvers. Range and power optimization FTO simulations are compared with comprehensive sweeps of trim solutions and FTO optimization shown to be effective and reliable in reaching an optimal when optimizing up to two redundant controls. Use of redundant controls is shown to be beneficial for improving performance. The search method takes almost 25 minutes of simulated flight for optimization to be complete. The optimization maneuver itself can sometimes drive the power required to high values, so a power limit is imposed to restrict the search to avoid conditions where power is more than5% higher than that of the initial trim state. With this modification, the time the optimization maneuver takes to complete is reduced down to 21 minutes without any significant change in the optimal power value.

Comparing the Effect of Thinking Maps Training Package Developed by the Thinking Maps Method on the Reading Performance of Dyslexic Students.

PubMed

Faramarzi, Salar; Moradi, Mohammadreza; Abedi, Ahmad

2018-06-01

The present study aimed to develop the thinking maps training package and compare its training effect with the thinking maps method on the reading performance of second and fifth grade of elementary school male dyslexic students. For this mixed method exploratory study, from among the above mentioned grades' students in Isfahan, 90 students who met the inclusion criteria were selected by multistage sampling and randomly assigned into six experimental and control groups. The data were collected by reading and dyslexia test and Wechsler Intelligence Scale for Children-fourth edition. The results of covariance analysis indicated a significant difference between the reading performance of the experimental (thinking maps training package and thinking maps method groups) and control groups ([Formula: see text]). Moreover, there were significant differences between the thinking maps training package group and thinking maps method group in some of the subtests ([Formula: see text]). It can be concluded that thinking maps training package and the thinking maps method exert a positive influence on the reading performance of dyslexic students; therefore, thinking maps can be used as an effective training and treatment method.

European multicentre database of healthy controls for [123I]FP-CIT SPECT (ENC-DAT): age-related effects, gender differences and evaluation of different methods of analysis.

PubMed

Varrone, Andrea; Dickson, John C; Tossici-Bolt, Livia; Sera, Terez; Asenbaum, Susanne; Booij, Jan; Kapucu, Ozlem L; Kluge, Andreas; Knudsen, Gitte M; Koulibaly, Pierre Malick; Nobili, Flavio; Pagani, Marco; Sabri, Osama; Vander Borght, Thierry; Van Laere, Koen; Tatsch, Klaus

2013-01-01

Dopamine transporter (DAT) imaging with [(123)I]FP-CIT (DaTSCAN) is an established diagnostic tool in parkinsonism and dementia. Although qualitative assessment criteria are available, DAT quantification is important for research and for completion of a diagnostic evaluation. One critical aspect of quantification is the availability of normative data, considering possible age and gender effects on DAT availability. The aim of the European Normal Control Database of DaTSCAN (ENC-DAT) study was to generate a large database of [(123)I]FP-CIT SPECT scans in healthy controls. SPECT data from 139 healthy controls (74 men, 65 women; age range 20-83 years, mean 53 years) acquired in 13 different centres were included. Images were reconstructed using the ordered-subset expectation-maximization algorithm without correction (NOACSC), with attenuation correction (AC), and with both attenuation and scatter correction using the triple-energy window method (ACSC). Region-of-interest analysis was performed using the BRASS software (caudate and putamen), and the Southampton method (striatum). The outcome measure was the specific binding ratio (SBR). A significant effect of age on SBR was found for all data. Gender had a significant effect on SBR in the caudate and putamen for the NOACSC and AC data, and only in the left caudate for the ACSC data (BRASS method). Significant effects of age and gender on striatal SBR were observed for all data analysed with the Southampton method. Overall, there was a significant age-related decline in SBR of between 4 % and 6.7 % per decade. This study provides a large database of [(123)I]FP-CIT SPECT scans in healthy controls across a wide age range and with balanced gender representation. Higher DAT availability was found in women than in men. An average age-related decline in DAT availability of 5.5 % per decade was found for both genders, in agreement with previous reports. The data collected in this study may serve as a reference database for nuclear medicine centres and for clinical trials using [(123)I]FP-CIT SPECT as the imaging marker.

Coordinated Control of Cross-Flow Turbines

NASA Astrophysics Data System (ADS)

Strom, Benjamin; Brunton, Steven; Polagye, Brian

2016-11-01

Cross-flow turbines, also known as vertical-axis turbines, have several advantages over axial-flow turbines for a number of applications including urban wind power, high-density arrays, and marine or fluvial currents. By controlling the angular velocity applied to the turbine as a function of angular blade position, we have demonstrated a 79 percent increase in cross-flow turbine efficiency over constant-velocity control. This strategy uses the downhill simplex method to optimize control parameter profiles during operation of a model turbine in a recirculating water flume. This optimization method is extended to a set of two turbines, where the blade motions and position of the downstream turbine are optimized to beneficially interact with the coherent structures in the wake of the upstream turbine. This control scheme has the potential to enable high-density arrays of cross-flow turbines to operate at cost-effective efficiency. Turbine wake and force measurements are analyzed for insight into the effect of a coordinated control strategy.

Generalized Predictive Control of Dynamic Systems with Rigid-Body Modes

NASA Technical Reports Server (NTRS)

Kvaternik, Raymond G.

2013-01-01

Numerical simulations to assess the effectiveness of Generalized Predictive Control (GPC) for active control of dynamic systems having rigid-body modes are presented. GPC is a linear, time-invariant, multi-input/multi-output predictive control method that uses an ARX model to characterize the system and to design the controller. Although the method can accommodate both embedded (implicit) and explicit feedforward paths for incorporation of disturbance effects, only the case of embedded feedforward in which the disturbances are assumed to be unknown is considered here. Results from numerical simulations using mathematical models of both a free-free three-degree-of-freedom mass-spring-dashpot system and the XV-15 tiltrotor research aircraft are presented. In regulation mode operation, which calls for zero system response in the presence of disturbances, the simulations showed reductions of nearly 100%. In tracking mode operations, where the system is commanded to follow a specified path, the GPC controllers produced the desired responses, even in the presence of disturbances.

Disease Risk Score (DRS) as a Confounder Summary Method: Systematic Review and Recommendations

PubMed Central

Tadrous, Mina; Gagne, Joshua J.; Stürmer, Til; Cadarette, Suzanne M.

2013-01-01

Purpose To systematically examine trends and applications of the disease risk score (DRS) as a confounder summary method. Methods We completed a systematic search of MEDLINE and Web of Science® to identify all English language articles that applied DRS methods. We tabulated the number of publications by year and type (empirical application, methodological contribution, or review paper) and summarized methods used in empirical applications overall and by publication year (<2000, ≥2000). Results Of 714 unique articles identified, 97 examined DRS methods and 86 were empirical applications. We observed a bimodal distribution in the number of publications over time, with a peak 1979-1980, and resurgence since 2000. The majority of applications with methodological detail derived DRS using logistic regression (47%), used DRS as a categorical variable in regression (93%), and applied DRS in a non-experimental cohort (47%) or case-control (42%) study. Few studies examined effect modification by outcome risk (23%). Conclusion Use of DRS methods has increased yet remains low. Comparative effectiveness research may benefit from more DRS applications, particularly to examine effect modification by outcome risk. Standardized terminology may facilitate identification, application, and comprehension of DRS methods. More research is needed to support the application of DRS methods, particularly in case-control studies. PMID:23172692

Controlled release of molecular components of dendrimer/bioactive complexes

DOEpatents

Segalman, Daniel J.; Wallace, J. Shield

1998-01-01

A method for releasing molecules (guest molecules) from the matrix formed by the structure of another molecule (host molecule) in a controllable manner has been invented. This method has many applications in science and industry. In addition, applications based on such molecular systems may revolutionize significant areas of medicine, in particular the treatment of cancer and of viral infection. Similar effects can also be obtained by controlled fragmentation of a source molecule, where the molecular fragments form the active principle.

Techniques for improving transients in learning control systems

NASA Technical Reports Server (NTRS)

Chang, C.-K.; Longman, Richard W.; Phan, Minh

1992-01-01

A discrete modern control formulation is used to study the nature of the transient behavior of the learning process during repetitions. Several alternative learning control schemes are developed to improve the transient performance. These include a new method using an alternating sign on the learning gain, which is very effective in limiting peak transients and also very useful in multiple-input, multiple-output systems. Other methods include learning at an increasing number of points progressing with time, or an increasing number of points of increasing density.

Controlled release of molecular components of dendrimer/bioactive complexes

DOEpatents

Segalman, D.J.; Wallace, J.S.

1998-08-18

A method for releasing molecules (guest molecules) from the matrix formed by the structure of another molecule (host molecule) in a controllable manner has been invented. This method has many applications in science and industry. In addition, applications based on such molecular systems may revolutionize significant areas of medicine, in particular the treatment of cancer and of viral infection. Similar effects can also be obtained by controlled fragmentation of a source molecule, where the molecular fragments form the active principle. 13 figs.

Active vibration control of functionally graded beams with piezoelectric layers based on higher order shear deformation theory

NASA Astrophysics Data System (ADS)

Bendine, K.; Boukhoulda, F. B.; Nouari, M.; Satla, Z.

2016-12-01

This paper reports on a study of active vibration control of functionally graded beams with upper and lower surface-bonded piezoelectric layers. The model is based on higher-order shear deformation theory and implemented using the finite element method (FEM). The proprieties of the functionally graded beam (FGB) are graded along the thickness direction. The piezoelectric actuator provides a damping effect on the FGB by means of a velocity feedback control algorithm. A Matlab program has been developed for the FGB model and compared with ANSYS APDL. Using Newmark's method numerical solutions are obtained for the dynamic equations of FGB with piezoelectric layers. Numerical results show the effects of the constituent volume fraction and the influence the feedback control gain on the frequency and dynamic response of FGBs.

Inhalation Exposure Method for Illegal Drugs.

PubMed

Inomata, Akiko; Ogata, Akio; Tada, Yukie; Nagasawa, Akemichi; Yuzawa, Katsuhiro; Ando, Hiroshi; Kubo, Yoshikazu; Takahashi, Hiroshi; Kaihoko, Fujifumi; Tanaka, Kazuyoshi; Nakajima, Jun'ichi; Suzuki, Atsuko; Uemura, Nozomi; Moriyasu, Takako; Watanabe, Daisuke; Ishihara, Kei; Usami, Takashi; Kamei, Satoru; Kohno, Yasuaki

2017-01-01

We developed a new inhalation exposure method to evaluate effects of synthetic cannabimimetics that are being distributed as new, unregulated drugs in the Tokyo area. We selected the commercial product "SOUTOU" containing AB-CHMINACA and 5F-AMB as the test drug and dried marshmallow (Althaea officinalis) leaves as the negative control. A half cigarette packed with dried marshmallow leaves or SOUTOU was ignited, then mainstream smoke from each was delivered to five mice in an exposure box. After the cigarettes were fully consumed, neurobehavioral observations and a catalepsy test were performed at 15, 30 and 60 min after exposure. The effluent air from the exposure box was poured into impingers containing acetonitrile (first impinger) and dimethyl sulfoxide (second impinger). The resulting solutions were analyzed to assess decomposition of the synthetic cannabimimetics. Mice exposed to SOUTOU smoke showed many excitement behaviors and some suppressive behaviors at 15, 30 and 60 min. These clearly included cannabimimetic specific pharmacological actions. Negative control mice also showed some suppressive behaviors at 15 min but these were attenuated at later times, nearly disappearing at 60 min. In addition, the behavioral effects observed in controls were less pronounced than those in SOUTOU exposed mice. The inhalation exposure method developed in our study would be effective for determining cannabinoid specific pharmacological effects of illegal drugs, as well as for assessing the presence of active compound(s) by comparing the test substance with a negative control.

The effectiveness of advance organiser model on students' academic achievement in learning work and energy

NASA Astrophysics Data System (ADS)

Gidena, Asay; Gebeyehu, Desta

2017-11-01

The purpose of this study was to investigate the effectiveness of the advance organiser model (AOM) on students' academic achievement in learning work and energy. The design of the study was quasi-experimental pretest-posttest nonequivalent control groups. The total population of the study was 139 students of three sections in Endabaguna preparatory school in Tigray Region, Ethiopia. Two sections with equivalent means on the pretest were taken to participate in the study purposely and one section assigned as the experimental group and the other section assigned as the control group randomly. The experimental group was taught using the lesson plan based on the AOM, and the control group was taught using the lesson plan based on the conventional teaching method. Pretest and posttest were administered before and after the treatment, respectively. Independent sample t-test was used to analyse the data at the probability level of 0.05. The findings of the study showed that the AOM was more effective than the conventional teaching method with effect size of 0.49. This model was also effective to teach male and female students and objectives namely understanding and application. However, both methods were equally important to teach work and energy under the objective knowledge level.

A Stability Enhancement Method for Centrifugal Compressors using Active Control Casing Treatment System

NASA Astrophysics Data System (ADS)

Zhao, Yuanyang; Xiao, Jun; Li, Liansheng; Yang, Qichao; Liu, Guangbin; Wang, Le

2015-08-01

The centrifugal compressors are widely used in many fields. When the centrifugal compressors operate at the edge of the surge line, the compressor will be unstable. In addition, if the centrifugal compressor runs at this situation long time, the damage will be occurred on compressor. There are some kinds of method to improve and enlarge the range of the centrifugal compressors, such as inlet guide vane, and casing treatment. For casing treatment method, some structures have been researched, such as holed recirculation, basic slot casing treatment and groove casing treatment. All these researches are the passive methods. This paper present a new stability enhancement method based Active Control Casing Treatment (ACCT). All parts of this new method are introduced in detail. The control strategy of the system is mentioned in the paper. As a research sample, a centrifugal compressor having this system is researched using CFD method. The study focuses on the effect of the active control system on the impeller flow. The vortex in impeller is changed by the active control system. And this leads to the suppression of the extension of vortex blockage in impeller and to contribute to the enhancement of the compressor operating range.

Optimal Operation and Management for Smart Grid Subsumed High Penetration of Renewable Energy, Electric Vehicle, and Battery Energy Storage System

NASA Astrophysics Data System (ADS)

Shigenobu, Ryuto; Noorzad, Ahmad Samim; Muarapaz, Cirio; Yona, Atsushi; Senjyu, Tomonobu

2016-04-01

Distributed generators (DG) and renewable energy sources have been attracting special attention in distribution systems in all over the world. Renewable energies, such as photovoltaic (PV) and wind turbine generators are considered as green energy. However, a large amount of DG penetration causes voltage deviation beyond the statutory range and reverse power flow at interconnection points in the distribution system. If excessive voltage deviation occurs, consumer's electric devices might break and reverse power flow will also has a negative impact on the transmission system. Thus, mass interconnections of DGs has an adverse effect on both of the utility and the customer. Therefore, reactive power control method is proposed previous research by using inverters attached DGs for prevent voltage deviations. Moreover, battery energy storage system (BESS) is also proposed for resolve reverse power flow. In addition, it is possible to supply high quality power for managing DGs and BESSs. Therefore, this paper proposes a method to maintain voltage, active power, and reactive power flow at interconnection points by using cooperative controlled of PVs, house BESSs, EVs, large BESSs, and existing voltage control devices. This paper not only protect distribution system, but also attain distribution loss reduction and effectivity management of control devices. Therefore mentioned control objectives are formulated as an optimization problem that is solved by using the Particle Swarm Optimization (PSO) algorithm. Modified scheduling method is proposed in order to improve convergence probability of scheduling scheme. The effectiveness of the proposed method is verified by case studies results and by using numerical simulations in MATLAB®.

Some Modeling Tools Available for Adaptive Management of South Florida Hydrology

NASA Astrophysics Data System (ADS)

Lal, W. A.; Van Zee, R. J.

2002-05-01

The hydrology of South Florida is a result of (1) the hydrology of the natural system; (2) the hydrology of the man made design components such as structures and levees designed to alter the natural hydrology; (3) influence of the operations imposed on the system using the design components. Successful restoration of the South Florida ecosystem depend not only on the design of the structural components, but also on its careful operation. The current discussion is focused on a number of optimal control methods that have recently become available to optimize restoration goals in the context of modeling. Optimal operation of the system can lessen stresses on some hydrological and ecological components. Careless operation can on the other hand lead to disastrous effects. Systems engineering and control theory have been used in the past to understand and operate simple systems such as the cruise control and the thermostat. Somewhat complex ones have been used to auto-pilot planes. The simplest control methods such as proportional and integral (PI) control are already used in the South Florida Water Management Model (SFWMM) for flood control and rain driven operations. The popular proportional-integral-differential (PID) control is widely used in industry for operational control of complex engineering systems. Some uses of PID control are investigated in the study. Other methods that an be used for operational control include Baysean methods, Kalman filtering and Neural network methods. A cursory evaluation of these methods is made in the discussion, along with the traditional methods used to operate complex engineering systems.

Thermal protection system gap analysis using a loosely coupled fluid-structural thermal numerical method

NASA Astrophysics Data System (ADS)

Huang, Jie; Li, Piao; Yao, Weixing

2018-05-01

A loosely coupled fluid-structural thermal numerical method is introduced for the thermal protection system (TPS) gap thermal control analysis in this paper. The aerodynamic heating and structural thermal are analyzed by computational fluid dynamics (CFD) and numerical heat transfer (NHT) methods respectively. An interpolation algorithm based on the control surface is adopted for the data exchanges on the coupled surface. In order to verify the analysis precision of the loosely coupled method, a circular tube example was analyzed, and the wall temperature agrees well with the test result. TPS gap thermal control performance was studied by the loosely coupled method successfully. The gap heat flux is mainly distributed in the small region at the top of the gap which is the high temperature region. Besides, TPS gap temperature and the power of the active cooling system (CCS) calculated by the traditional uncoupled method are higher than that calculated by the coupled method obviously. The reason is that the uncoupled method doesn't consider the coupled effect between the aerodynamic heating and structural thermal, however the coupled method considers it, so TPS gap thermal control performance can be analyzed more accurately by the coupled method.

Frequency control of wind turbine in power system

NASA Astrophysics Data System (ADS)

Xu, Huawei

2018-06-01

In order to improve the stability of the overall frequency of the power system, automatic power generation control and secondary frequency adjustment were applied. Automatic power generation control was introduced into power generation planning. A dual-fed wind generator power regulation model suitable for secondary frequency regulation was established. The results showed that this method satisfied the basic requirements of frequency regulation control of large-scale wind power access power systems and improved the stability and reliability of power system operation. Therefore, this system frequency control method and strategy is relatively simple. The effect is significant. The system frequency can quickly reach a steady state. It is worth applying and promoting.

On stochastic control and optimal measurement strategies. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Kramer, L. C.

1971-01-01

The control of stochastic dynamic systems is studied with particular emphasis on those which influence the quality or nature of the measurements which are made to effect control. Four main areas are discussed: (1) the meaning of stochastic optimality and the means by which dynamic programming may be applied to solve a combined control/measurement problem; (2) a technique by which it is possible to apply deterministic methods, specifically the minimum principle, to the study of stochastic problems; (3) the methods described are applied to linear systems with Gaussian disturbances to study the structure of the resulting control system; and (4) several applications are considered.

The effect of problem solving and decision making skills on tendency to depression and anxiety in patients with type 2 diabetes

PubMed Central

Abazarian, Elaheh; Baboli, M Teimourzadeh; Abazarian, Elham; Ghashghaei, F Esteki

2015-01-01

Background: Diabetes is the most prevalent disease that has involved 177 million people all over the world and, due to this, these patients suffer from depression and anxiety and they should use special methods for controlling the same. The aim of this research is the study of the effect of problem solving and decision making skill on the rate of the tendency to depression and anxiety. Materials and Methods: This research is a quasi-experimental (case-control) study. Statistically, the population of the present study was all diabetic patients of Qaemshahr who were controlled by physicians in 2011-2012. Thirty files were selected randomly from them and divided into two 15 patients’ groups (control and subject group) randomly. The measurement tools were Back depression inventory (21 items) and Zank anxiety questionnaire that were distributed among two groups. Then, the subject group participated in eight sessions of teaching problem solving and decision making courses separately, and the second group (control group) did not receive any instruction. Results: Finally, both groups had passed post-test and the data obtained from the questionnaires were studied by variance analysis statistical methods. Conclusion: The results showed that teaching problem solving and decision making skills was very effective in reducing diabetic patients’ depression and anxiety and resulted in reducing their depression and anxiety. PMID:26261814

Biologically Based Methods for Control of Fumonisin-Producing Fusarium Species and Reduction of the Fumonisins

PubMed Central

Alberts, Johanna F.; van Zyl, Willem H.; Gelderblom, Wentzel C. A.

2016-01-01

Infection by the fumonisin-producing Fusarium spp. and subsequent fumonisin contamination of maize adversely affect international trade and economy with deleterious effects on human and animal health. In developed countries high standards of the major food suppliers and retailers are upheld and regulatory controls deter the importation and local marketing of fumonisin-contaminated food products. In developing countries regulatory measures are either lacking or poorly enforced, due to food insecurity, resulting in an increased mycotoxin exposure. The lack and poor accessibility of effective and environmentally safe control methods have led to an increased interest in practical and biological alternatives to reduce fumonisin intake. These include the application of natural resources, including plants, microbial cultures, genetic material thereof, or clay minerals pre- and post-harvest. Pre-harvest approaches include breeding for resistant maize cultivars, introduction of biocontrol microorganisms, application of phenolic plant extracts, and expression of antifungal proteins and fumonisin degrading enzymes in transgenic maize cultivars. Post-harvest approaches include the removal of fumonisins by natural clay adsorbents and enzymatic degradation of fumonisins through decarboxylation and deamination by recombinant carboxylesterase and aminotransferase enzymes. Although, the knowledge base on biological control methods has expanded, only a limited number of authorized decontamination products and methods are commercially available. As many studies detailed the use of natural compounds in vitro, concepts in reducing fumonisin contamination should be developed further for application in planta and in the field pre-harvest, post-harvest, and during storage and food-processing. In developed countries an integrated approach, involving good agricultural management practices, hazard analysis and critical control point (HACCP) production, and storage management, together with selected biologically based treatments, mild chemical and physical treatments could reduce fumonisin contamination effectively. In rural subsistence farming communities, simple, practical, and culturally acceptable hand-sorting, maize kernel washing, and dehulling intervention methods proved to be effective as a last line of defense for reducing fumonisin exposure. Biologically based methods for control of fumonisin-producing Fusarium spp. and decontamination of the fumonisins could have potential commercial application, while simple and practical intervention strategies could also impact positively on food safety and security, especially in rural populations reliant on maize as a dietary staple. PMID:27199904

Experimental Study of Flexible Plate Vibration Control by Using Two-Loop Sliding Mode Control Strategy

NASA Astrophysics Data System (ADS)

Yang, Jingyu; Lin, Jiahui; Liu, Yuejun; Yang, Kang; Zhou, Lanwei; Chen, Guoping

2017-08-01

It is well known that intelligent control theory has been used in many research fields, novel modeling method (DROMM) is used for flexible rectangular active vibration control, and then the validity of new model is confirmed by comparing finite element model with new model. In this paper, taking advantage of the dynamics of flexible rectangular plate, a two-loop sliding mode (TSM) MIMO approach is introduced for designing multiple-input multiple-output continuous vibration control system, which can overcome uncertainties, disturbances or unstable dynamics. An illustrative example is given in order to show the feasibility of the method. Numerical simulations and experiment confirm the effectiveness of the proposed TSM MIMO controller.

Ares I Flight Control System Overview

NASA Technical Reports Server (NTRS)

Hall, Charles; Lee, Chong; Jackson, Mark; Whorton, Mark; West, mark; Brandon, Jay; Hall, Rob A.; Jang, Jimmy; Bedrossian, Naz; Compton, Jimmy;

An improved predictive functional control method with application to PMSM systems

NASA Astrophysics Data System (ADS)

Li, Shihua; Liu, Huixian; Fu, Wenshu

2017-01-01

In common design of prediction model-based control method, usually disturbances are not considered in the prediction model as well as the control design. For the control systems with large amplitude or strong disturbances, it is difficult to precisely predict the future outputs according to the conventional prediction model, and thus the desired optimal closed-loop performance will be degraded to some extent. To this end, an improved predictive functional control (PFC) method is developed in this paper by embedding disturbance information into the system model. Here, a composite prediction model is thus obtained by embedding the estimated value of disturbances, where disturbance observer (DOB) is employed to estimate the lumped disturbances. So the influence of disturbances on system is taken into account in optimisation procedure. Finally, considering the speed control problem for permanent magnet synchronous motor (PMSM) servo system, a control scheme based on the improved PFC method is designed to ensure an optimal closed-loop performance even in the presence of disturbances. Simulation and experimental results based on a hardware platform are provided to confirm the effectiveness of the proposed algorithm.

Testing Mediators of Intervention Effects in Randomized Controlled Trials: An Evaluation of Three Depression Prevention Programs

ERIC Educational Resources Information Center

Stice, Eric; Rohde, Paul; Seeley, John R.; Gau, Jeff M.

2010-01-01

Objective: Evaluate a new 5-step method for testing mediators hypothesized to account for the effects of depression prevention programs. Method: In this indicated prevention trial, at-risk teens with elevated depressive symptoms were randomized to a group cognitive-behavioral (CB) intervention, group supportive expressive intervention, CB…

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…

Controlling range expansion in habitat networks by adaptively targeting source populations.

PubMed

Hock, Karlo; Wolff, Nicholas H; Beeden, Roger; Hoey, Jessica; Condie, Scott A; Anthony, Kenneth R N; Possingham, Hugh P; Mumby, Peter J

2016-08-01

Controlling the spread of invasive species, pests, and pathogens is often logistically limited to interventions that target specific locations at specific periods. However, in complex, highly connected systems, such as marine environments connected by ocean currents, populations spread dynamically in both space and time via transient connectivity links. This results in nondeterministic future distributions of species in which local populations emerge dynamically and concurrently over a large area. The challenge, therefore, is to choose intervention locations that will maximize the effectiveness of the control efforts. We propose a novel method to manage dynamic species invasions and outbreaks that identifies the intervention locations most likely to curtail population expansion by selectively targeting local populations most likely to expand their future range. Critically, at any point during the development of the invasion or outbreak, the method identifies the local intervention that maximizes the long-term benefit across the ecosystem by restricting species' potential to spread. In so doing, the method adaptively selects the intervention targets under dynamically changing circumstances. To illustrate the effectiveness of the method we applied it to controlling the spread of crown-of-thorns starfish (Acanthaster sp.) outbreaks across Australia's Great Barrier Reef. Application of our method resulted in an 18-fold relative improvement in management outcomes compared with a random targeting of reefs in putative starfish control scenarios. Although we focused on applying the method to reducing the spread of an unwanted species, it can also be used to facilitate the spread of desirable species through connectivity networks. For example, the method could be used to select those fragments of habitat most likely to rebuild a population if they were sufficiently well protected. © 2016 Society for Conservation Biology.

[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.

Using automated voice messages linked to telephone counselling to increase post-menstrual regulation contraceptive uptake and continuation in Bangladesh: study protocol for a randomised controlled trial.

PubMed

Reiss, Kate; Andersen, Kathryn; Barnard, Sharmani; Ngo, Thoai D; Biswas, Kamal; Smith, Christopher; Carpenter, James; Church, Kathryn; Nuremowla, Sadid; Pearson, Erin

2017-10-03

Adoption of modern contraceptive methods after menstrual regulation (MR) is thought to reduce subsequent unwanted pregnancy and abortion. Long-acting reversible contraceptives (LARCs) are highly effective at reducing unintended pregnancy, but uptake in Bangladesh is low. Providing information on the most effective methods of contraception increases uptake of more effective methods. This protocol describes a randomised controlled trial of an intervention delivered by mobile phone designed to support post-MR contraceptive use in Bangladesh. This is a multi-site single blind individual randomised controlled trial. At least 960 women undergoing MR procedures at selected facilities will be recruited after their procedure by female research assistants. Women will be randomised into the control or intervention group with a 1:1 ratio. All participants will receive usual clinic care, including contraceptive counselling and the telephone number of a non-toll-free call centre which provides counselling on MR and contraception. During the 4 months after their MR procedure, intervention participants will be sent 11 recorded interactive voice messages to their mobile phone about contraception with a focus on their chosen method and LARCs. Each message allows the participant to connect directly to the call centre. The intervention is free to the user. The control group will receive no messages delivered by mobile phone. All participants will be asked to complete an in-person questionnaire at recruitment and follow-up questionnaires by telephone at 2 weeks, 4 months and 12 months after their MR. The primary outcome for the trial will be self-reported LARC use 4 months post-MR. Secondary outcomes include LARC use at 2 weeks and 12 months post-MR, use of any effective modern contraceptive method at 2 weeks, 4 months and 12 months post-MR, and contraceptive discontinuation, contraceptive method switching, pregnancy, subsequent MR and experience of violence during the 12 month study period. Mobile phones offer a low-cost mechanism for providing individualised support to women with contraception outside of the clinic setting. This study will provide information on the effects of such an intervention among MR clients in Bangladesh. Trial registered with clinicaltrials.gov Registration number: NCT02579785 Date of registration: 16th October 2015.

Alternative outcome definitions and their effect on the performance of methods for observational outcome studies.

PubMed

Reich, Christian G; Ryan, Patrick B; Schuemie, Martijn J

2013-10-01

A systematic risk identification system has the potential to test marketed drugs for important Health Outcomes of Interest or HOI. For each HOI, multiple definitions are used in the literature, and some of them are validated for certain databases. However, little is known about the effect of different definitions on the ability of methods to estimate their association with medical products. Alternative definitions of HOI were studied for their effect on the performance of analytical methods in observational outcome studies. A set of alternative definitions for three HOI were defined based on literature review and clinical diagnosis guidelines: acute kidney injury, acute liver injury and acute myocardial infarction. The definitions varied by the choice of diagnostic codes and the inclusion of procedure codes and lab values. They were then used to empirically study an array of analytical methods with various analytical choices in four observational healthcare databases. The methods were executed against predefined drug-HOI pairs to generate an effect estimate and standard error for each pair. These test cases included positive controls (active ingredients with evidence to suspect a positive association with the outcome) and negative controls (active ingredients with no evidence to expect an effect on the outcome). Three different performance metrics where used: (i) Area Under the Receiver Operator Characteristics (ROC) curve (AUC) as a measure of a method's ability to distinguish between positive and negative test cases, (ii) Measure of bias by estimation of distribution of observed effect estimates for the negative test pairs where the true effect can be assumed to be one (no relative risk), and (iii) Minimal Detectable Relative Risk (MDRR) as a measure of whether there is sufficient power to generate effect estimates. In the three outcomes studied, different definitions of outcomes show comparable ability to differentiate true from false control cases (AUC) and a similar bias estimation. However, broader definitions generating larger outcome cohorts allowed more drugs to be studied with sufficient statistical power. Broader definitions are preferred since they allow studying drugs with lower prevalence than the more precise or narrow definitions while showing comparable performance characteristics in differentiation of signal vs. no signal as well as effect size estimation.

Meeting Postpartum Women’s Family Planning Needs Through Integrated Family Planning and Immunization Services: Results of a Cluster-Randomized Controlled Trial in Rwanda

PubMed Central

Dulli, Lisa S; Eichleay, Marga; Rademacher, Kate; Sortijas, Steve; Nsengiyumva, Théophile

2016-01-01

ABSTRACT Objective The primary objective of this study was to test the effectiveness of integrating family planning service components into infant immunization services to increase modern contraceptive method use among postpartum women. Methods The study was a separate sample, parallel, cluster-randomized controlled trial. Fourteen randomly selected primary health facilities were equally allocated to intervention (integrated family planning and immunization services at the same time and location) and control groups (standard immunization services only). At baseline (May–June 2010), we interviewed postpartum women attending immunization services for their infant aged 6 to 12 months using a structured questionnaire. A separate sample of postpartum women was interviewed 16 months later after implementation of the experimental health service intervention. We used linear mixed regression models to test the study hypothesis that postpartum women attending immunization services for their infants aged 6–12 months in the intervention facilities will be more likely to use a modern contraceptive method than postpartum women attending immunization services for their infants aged 6–12 months in control group facilities. Results We interviewed and analyzed data for 825 women from the intervention group and 829 women from the control group. Results showed the intervention had a statistically significant, positive effect on modern contraceptive method use among intervention group participants compared with control group participants (regression coefficient, 0.15; 90% confidence interval [CI], 0.04 to 0.26). Although we conducted a 1-sided significance test, this effect was also significant at the 2-sided test with alpha = .05. Among those women who did not initiate a contraceptive method, awaiting the return of menses was the most common reason cited for non-use of a method. Women in both study groups overwhelmingly supported the concept of integrating family planning service components into infant immunization services (97.9% in each group), and service data collected during the intervention period did not indicate that the intervention had any negative effect on infant immunization service uptake. Conclusion Integrating family planning service components into infant immunization services can be an acceptable and effective strategy to increase contraceptive use among postpartum women. Additional research is needed to examine the extent to which this integration strategy can be replicated in other health care settings. Future research should also explore persistent misconceptions regarding the relationship between return of menses and return to fertility during the postpartum period. PMID:27016545

Meta-analysis of studies on chemical, physical and biological agents in the control of Aedes aegypti.

PubMed

Lima, Estelita Pereira; Goulart, Marília Oliveira Fonseca; Rolim Neto, Modesto Leite

2015-09-04

Aedes aegypti is a vector of international concern because it can transmit to humans three important arboviral diseases: yellow fever, dengue and chikungunya. Epidemics that are repeated year after year in a variety of urban centers indicate that there are control failures, allowing the vector to continue expanding. To identify the most effective vector control strategies and the factors that contributed to the success or failure of each strategy, we carried out a systematic review with meta-analysis of articles published in 12 databases, from 1974 to the month of December 2013. We evaluated the association between the use of whatever chemical substance, mechanical agent, biological or integrated actions against A. aegypti and the control of the vector, as measured by 10 indicators. We found 2,791 articles, but after careful selection, only 26 studies remained for analysis related to control interventions implemented in 15 countries, with 5 biological, 5 chemical, 3 mechanical and 13 integrated strategies. The comparison among all of them, indicated that the control of A. aegypti is significantly associated with the type of strategy used, and that integrated interventions consist of the most effective method for controlling A. aegypti. The most effective control method was the integrated approach, considering the influence of eco-bio-social determinants in the virus-vector-man epidemiological chain, and community involvement, starting with community empowerment as active agents of vector control.

Effect of method of euthanasia on sperm motility of mature Sprague-Dawley rats.

PubMed

Stutler, Shannon A; Johnson, Eric W; Still, Kenneth R; Schaeffer, David J; Hess, Rex A; Arfsten, Darryl P

2007-03-01

Euthanasia is one of the most commonly performed procedures in laboratory animal settings. The method of euthanasia may affect experimental results in studies using animals and must be compatible with research objectives including subsequent tissue analyses. Our present study was performed to evaluate the effects of 7 euthanasia methods on sperm motility in mature rats. Rats were euthanized using CO2, 2 commercially available euthanasia solutions (Beuthanasia-D and Sleepaway), and 4 volatile anesthetics (enflurane, halothane, isoflurane, and sevoflurane). Rats euthanized by rapid decapitation alone served as negative controls, and a-chlorohydrin-treated rats euthanized by rapid decapitation were positive controls for sperm impairment. For 5 of these methods, we also measured time to ataxia, recumbency, respiratory arrest, and no auscultable heartbeat. Immediately after euthanasia of each rat, distal caudal epididymides were removed; 1 was processed for automated sperm motility analysis, and the other was frozen for subsequent concentration analysis. Time to all measured parameters was less for volatile anesthetics than for Beuthanasia-D. Times to last respiration and no heartbeat were less for halothane and isoflurane than for enflurane and sevoflurane. Percentage motile sperm did not differ significantly between methods. Percentage progressively motile sperm did not vary significantly between methods except for Beuthanasia-D, for which it was significantly less than the negative control value. Specific sperm motion parameters for each euthanasia method except CO2 and Sleepaway varied significantly from the negative control. Our results indicate that the method of euthanasia is an important consideration when rat sperm motility parameters must be evaluated.

On Application of Model Predictive Control to Power Converter with Switching

NASA Astrophysics Data System (ADS)

Zanma, Tadanao; Fukuta, Junichi; Doki, Shinji; Ishida, Muneaki; Okuma, Shigeru; Matsumoto, Takashi; Nishimori, Eiji

This paper concerns a DC-DC converter control. In DC-DC converters, there exist both continuous components such as inductance, conductance and resistance and discrete ones, IGBT and MOSFET as semiconductor switching elements. Such a system can be regarded as a hybrid dynamical system. Thus, this paper presents a dc-dc control technique based on the model predictive control. Specifically, a case in which the load of the dc-dc converter changes from active to sleep is considered. In the case, a control method which makes the output voltage follow to the reference quickly in transition, and the switching frequency be constant in steady state. In addition, in applying the model predictive control to power electronics circuits, the switching characteristic of the device and the restriction condition for protection are also considered. The effectiveness of the proposed method is illustrated by comparing a conventional method through some simulation results.

pKWmEB: integration of Kruskal-Wallis test with empirical Bayes under polygenic background control for multi-locus genome-wide association study.

PubMed

Ren, Wen-Long; Wen, Yang-Jun; Dunwell, Jim M; Zhang, Yuan-Ming

2018-03-01

Although nonparametric methods in genome-wide association studies (GWAS) are robust in quantitative trait nucleotide (QTN) detection, the absence of polygenic background control in single-marker association in genome-wide scans results in a high false positive rate. To overcome this issue, we proposed an integrated nonparametric method for multi-locus GWAS. First, a new model transformation was used to whiten the covariance matrix of polygenic matrix K and environmental noise. Using the transferred model, Kruskal-Wallis test along with least angle regression was then used to select all the markers that were potentially associated with the trait. Finally, all the selected markers were placed into multi-locus model, these effects were estimated by empirical Bayes, and all the nonzero effects were further identified by a likelihood ratio test for true QTN detection. This method, named pKWmEB, was validated by a series of Monte Carlo simulation studies. As a result, pKWmEB effectively controlled false positive rate, although a less stringent significance criterion was adopted. More importantly, pKWmEB retained the high power of Kruskal-Wallis test, and provided QTN effect estimates. To further validate pKWmEB, we re-analyzed four flowering time related traits in Arabidopsis thaliana, and detected some previously reported genes that were not identified by the other methods.

Current harmonics elimination control method for six-phase PM synchronous motor drives.

PubMed

Yuan, Lei; Chen, Ming-liang; Shen, Jian-qing; Xiao, Fei

2015-11-01

To reduce the undesired 5th and 7th stator harmonic current in the six-phase permanent magnet synchronous motor (PMSM), an improved vector control algorithm was proposed based on vector space decomposition (VSD) transformation method, which can control the fundamental and harmonic subspace separately. To improve the traditional VSD technology, a novel synchronous rotating coordinate transformation matrix was presented in this paper, and only using the traditional PI controller in d-q subspace can meet the non-static difference adjustment, the controller parameter design method is given by employing internal model principle. Moreover, the current PI controller parallel with resonant controller is employed in x-y subspace to realize the specific 5th and 7th harmonic component compensation. In addition, a new six-phase SVPWM algorithm based on VSD transformation theory is also proposed. Simulation and experimental results verify the effectiveness of current decoupling vector controller. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

1977 Kansas Field Crop Insect Control Recommendations.

ERIC Educational Resources Information Center

Brooks, Leroy; Gates, Dell E.

This publication is prepared to aid producers in selecting methods of insect population management that have proved effective under Kansas conditions. Topics covered include insect control on alfalfa, soil insects attacking corn, insects attacking above-ground parts of corn, and sorghum, wheat, and soybean insect control. The insecticides…

Job-Advertising and Wage Control Spillovers.

ERIC Educational Resources Information Center

Goodwin, William B.; Carlson, John A.

1981-01-01

This article examines the tradeoffs between wages and job-related advertising in the recruitment of new employees. Hypothesizes that when wages are limited by controls, firms increase their use of nonwage recruiting methods. Also examines the effect of the Nixon wage controls on newspaper help-wanted advertisements. (Author/CT)

Considerations for the implementation and operation of stormwater control measure (SCM) performance monitoring systems

EPA Science Inventory

Green infrastructure (GI) studies are needed to make informed decisions about whether or not to select GI technologies over traditional urban drainage control methods and to assist in the timing of effective maintenance. Two permeable pavement infiltration stormwater control meas...

Adaptive control of servo system based on LuGre model

NASA Astrophysics Data System (ADS)

Jin, Wang; Niancong, Liu; Jianlong, Chen; Weitao, Geng

2018-03-01

This paper established a mechanical model of feed system based on LuGre model. In order to solve the influence of nonlinear factors on the system running stability, a nonlinear single observer is designed to estimate the parameter z in the LuGre model and an adaptive friction compensation controller is designed. Simulink simulation results show that the control method can effectively suppress the adverse effects of friction and external disturbances. The simulation show that the adaptive parameter kz is between 0.11-0.13, and the value of gamma1 is between 1.9-2.1. Position tracking error reaches level 10-3 and is stabilized near 0 values within 0.3 seconds, the compensation method has better tracking accuracy and robustness.

Study on antilock brake system with elastic membrane vibration generated by controlled solenoid excitation

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

Wibowo,, E-mail: wibowo-uns@yahoo.com; Zakaria,, E-mail: zakaaria27@gmail.com; Lambang, Lullus, E-mail: lulus-l@yahoo.com

The most effective chassis control system for improving vehicle safety during severe braking is anti-lock braking system (ABS). Antilock effect can be gained by vibrate the pad brake at 7 to 20 cycle per second. The aim of this study is to design a new method of antilock braking system with membrane elastic vibrated by solenoid. The influence of the pressure fluctuations of brake fluid is investigated. Vibration data is collected using a small portable accelerometer-slam stick. The experiment results that the vibration of brake pad caused by controlled solenoid excitation at 10 Hz is obtained by our new method. Themore » result of measurements can be altered by varying brake fluid pressure.« less

Study on antilock brake system with elastic membrane vibration generated by controlled solenoid excitation

NASA Astrophysics Data System (ADS)

Wibowo, Zakaria, Lambang, Lullus; Triyono, Muhayat, Nurul

2016-03-01

The most effective chassis control system for improving vehicle safety during severe braking is anti-lock braking system (ABS). Antilock effect can be gained by vibrate the pad brake at 7 to 20 cycle per second. The aim of this study is to design a new method of antilock braking system with membrane elastic vibrated by solenoid. The influence of the pressure fluctuations of brake fluid is investigated. Vibration data is collected using a small portable accelerometer-slam stick. The experiment results that the vibration of brake pad caused by controlled solenoid excitation at 10 Hz is obtained by our new method. The result of measurements can be altered by varying brake fluid pressure.

Desynchronization in an ensemble of globally coupled chaotic bursting neuronal oscillators by dynamic delayed feedback control

NASA Astrophysics Data System (ADS)

Che, Yanqiu; Yang, Tingting; Li, Ruixue; Li, Huiyan; Han, Chunxiao; Wang, Jiang; Wei, Xile

2015-09-01

In this paper, we propose a dynamic delayed feedback control approach or desynchronization of chaotic-bursting synchronous activities in an ensemble of globally coupled neuronal oscillators. We demonstrate that the difference signal between an ensemble's mean field and its time delayed state, filtered and fed back to the ensemble, can suppress the self-synchronization in the ensemble. These individual units are decoupled and stabilized at the desired desynchronized states while the stimulation signal reduces to the noise level. The effectiveness of the method is illustrated by examples of two different populations of globally coupled chaotic-bursting neurons. The proposed method has potential for mild, effective and demand-controlled therapy of neurological diseases characterized by pathological synchronization.

Quasi-experimental Effectiveness of Cognitive-behavioral Therapy on Reliving Migraine Headaches in Migraine Sufferers.

PubMed

Ebrahimi Moghadam, Hosein; Karimi, Ahoo; Seifi, Kimia

2017-01-01

This study aimed to investigate the effectiveness of cognitive-behavioral therapy on relieving migraine headaches in migraine sufferers. In this quasi-experimental study with pre-test and post-test method, the samples were outpatients of public hospitals in Ilam City, southwestern Iran since May-Jul 2010. They were selected based on inclusion and exclusion criteria, and divided into experimental and control groups. The data were analyzed using SPSS ver. 16 and via multivariate covariance method. Cognitive-behavioral therapy affected on reducing the duration of symptoms of migraine in sufferers ( P <0.05). Cognitive behavioral therapy effects on reducing the time duration of symptoms of migraine headaches. Thistherapeutic method increases the level of individual, familial, social and occupational activities by reducing the time duration of symptoms and this method helps the individuals to resume their activities and regain their previous control instead of founding themselves incapable and helpless due to the pain they suffer from.

The prediction of pressure distributions on an arrow-wing configuration including the effect of camber, twist, and a wing fin

NASA Technical Reports Server (NTRS)

Bobbitt, P. J.; Manro, M. E.; Kulfan, R. M.

1980-01-01

Wind tunnel tests of an arrow wing body configuration consisting of flat, twisted, and cambered twisted wings were conducted at Mach numbers from 0.40 to 2.50 to provide an experimental data base for comparison with theoretical methods. A variety of leading and trailing edge control surface deflections were included in these tests, and in addition, the cambered twisted wing was tested with an outboard vertical fin to determine its effect on wing and control surface loads. Theory experiment comparisons show that current state of the art linear and nonlinear attached flow methods were adequate at small angles of attack typical of cruise conditions. The incremental effects of outboard fin, wing twist, and wing camber are most accurately predicted by the advanced panel method PANAIR. Results of the advanced panel separated flow method, obtained with an early version of the program, show promise that accurate detailed pressure predictions may soon be possible for an aeroelasticity deformed wing at high angles of attack.

Prevention methods for pest control and their use in Poland.

PubMed

Matyjaszczyk, Ewa

2015-04-01

Prevention methods can still be a cost-effective and efficient tool for pest control. Rational use of prevention methods is a feasible way to reduce dependency on chemical protection in agriculture. Costs, workload and farmers' awareness are key issues, however. In Poland, crop rotation is used as a method for pest control only to a limited extent owing to the high share of cereals in the crop structure. The choice of resistant varieties is satisfactory, but farmers should make use of qualified seed material more often. Liming is recommended on the majority of farms on account of widespread soil acidity. Favourable aspects as regards the prevention of pest development are biodiversity and the popularity of prevention cultivation techniques. © 2014 Society of Chemical Industry.

Parametric system identification of catamaran for improving controller design

NASA Astrophysics Data System (ADS)

Timpitak, Surasak; Prempraneerach, Pradya; Pengwang, Eakkachai

2018-01-01

This paper presents an estimation of simplified dynamic model for only surge- and yaw- motions of catamaran by using system identification (SI) techniques to determine associated unknown parameters. These methods will enhance the performance of designing processes for the motion control system of Unmanned Surface Vehicle (USV). The simulation results demonstrate an effective way to solve for damping forces and to determine added masses by applying least-square and AutoRegressive Exogenous (ARX) methods. Both methods are then evaluated according to estimated parametric errors from the vehicle’s dynamic model. The ARX method, which yields better estimated accuracy, can then be applied to identify unknown parameters as well as to help improving a controller design of a real unmanned catamaran.

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.

Effects of Elastic Resistance Exercise on Muscle Strength and Functional Performance in Healthy Adults: A Systematic Review and Meta-Analysis.

PubMed

de Oliveira, Poliana Alves; Blasczyk, Juscelino Castro; Souza Junior, Gerson; Lagoa, Karina Ferreira; Soares, Milene; de Oliveira, Ricardo Jacó; Filho, Paulo José Barbosa Gutierres; Carregaro, Rodrigo Luiz; Martins, Wagner Rodrigues

2017-04-01

Elastic Resistance Exercise (ERE) has already demonstrated its effectiveness in older adults and, when combined with the resistance generated by fixed loads, in adults. This review summarizes the effectiveness of ERE performed as isolated method on muscle strength and functional performance in healthy adults. A database search was performed (MEDLine, Cochrane Library, PEDro and Web of Knowledge) to identify controlled clinical trials in English language. The mean difference (MD) with 95% confidence intervals (CIs) and overall effect size were calculated for all comparisons. The PEDro scale was used assess the methodological quality. From the 93 articles identified by the search strategy, 5 met the inclusion criteria, in which 3 presented high quality (PEDro > 6). Meta-analyses demonstrated that the effects of ERE were superior when compared with passive control on functional performance and muscle strength. When compared with active controls, the effect of ERE was inferior on function performance and with similar effect on muscle strength. ERE are effective to improve functional performance and muscle strength when compared with no intervention, in healthy adults. ERE are not superior to other methods of resistance training to improve functional performance and muscle strength in health adults.

Multiple model predictive control for optimal drug administration of mixed immunotherapy and chemotherapy of tumours.

PubMed

Sharifi, N; Ozgoli, S; Ramezani, A

2017-06-01

Mixed immunotherapy and chemotherapy of tumours is one of the most efficient ways to improve cancer treatment strategies. However, it is important to 'design' an effective treatment programme which can optimize the ways of combining immunotherapy and chemotherapy to diminish their imminent side effects. Control engineering techniques could be used for this. The method of multiple model predictive controller (MMPC) is applied to the modified Stepanova model to induce the best combination of drugs scheduling under a better health criteria profile. The proposed MMPC is a feedback scheme that can perform global optimization for both tumour volume and immune competent cell density by performing multiple constraints. Although current studies usually assume that immunotherapy has no side effect, this paper presents a new method of mixed drug administration by employing MMPC, which implements several constraints for chemotherapy and immunotherapy by considering both drug toxicity and autoimmune. With designed controller we need maximum 57% and 28% of full dosage of drugs for chemotherapy and immunotherapy in some instances, respectively. Therefore, through the proposed controller less dosage of drugs are needed, which contribute to suitable results with a perceptible reduction in medicine side effects. It is observed that in the presence of MMPC, the amount of required drugs is minimized, while the tumour volume is reduced. The efficiency of the presented method has been illustrated through simulations, as the system from an initial condition in the malignant region of the state space (macroscopic tumour volume) transfers into the benign region (microscopic tumour volume) in which the immune system can control tumour growth. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluating a complex system-wide intervention using the difference in differences method: the Delivering Choice Programme.

PubMed

Round, Jeff; Drake, Robyn; Kendall, Edward; Addicott, Rachael; Agelopoulos, Nicky; Jones, Louise

2015-03-01

We report the use of difference in differences (DiD) methodology to evaluate a complex, system-wide healthcare intervention. We use the worked example of evaluating the Marie Curie Delivering Choice Programme (DCP) for advanced illness in a large urban healthcare economy. DiD was selected because a randomised controlled trial was not feasible. The method allows for before and after comparison of changes that occur in an intervention site with a matched control site. This enables analysts to control for the effect of the intervention in the absence of a local control. Any policy, seasonal or other confounding effects over the test period are assumed to have occurred in a balanced way at both sites. Data were obtained from primary care trusts. Outcomes were place of death, inpatient admissions, length of stay and costs. Small changes were identified between pre- and post-DCP outputs in the intervention site. The proportion of home deaths and median cost increased slightly, while the number of admissions per patient and the average length of stay per admission decreased slightly. None of these changes was statistically significant. Effects estimates were limited by small numbers accessing new services and selection bias in sample population and comparator site. In evaluating the effect of a complex healthcare intervention, the choice of analysis method and output measures is crucial. Alternatives to randomised controlled trials may be required for evaluating large scale complex interventions and the DiD approach is suitable, subject to careful selection of measured outputs and control population. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Simulation analysis of adaptive cruise prediction control

NASA Astrophysics Data System (ADS)

Zhang, Li; Cui, Sheng Min

2017-09-01

Predictive control is suitable for multi-variable and multi-constraint system control.In order to discuss the effect of predictive control on the vehicle longitudinal motion, this paper establishes the expected spacing model by combining variable pitch spacing and the of safety distance strategy. The model predictive control theory and the optimization method based on secondary planning are designed to obtain and track the best expected acceleration trajectory quickly. Simulation models are established including predictive and adaptive fuzzy control. Simulation results show that predictive control can realize the basic function of the system while ensuring the safety. The application of predictive and fuzzy adaptive algorithm in cruise condition indicates that the predictive control effect is better.

Comparing methods for assessing the effectiveness of subnational REDD+ initiatives

NASA Astrophysics Data System (ADS)

Bos, Astrid B.; Duchelle, Amy E.; Angelsen, Arild; Avitabile, Valerio; De Sy, Veronique; Herold, Martin; Joseph, Shijo; de Sassi, Claudio; Sills, Erin O.; Sunderlin, William D.; Wunder, Sven

2017-07-01

The central role of forests in climate change mitigation, as recognized in the Paris agreement, makes it increasingly important to develop and test methods for monitoring and evaluating the carbon effectiveness of REDD+. Over the last decade, hundreds of subnational REDD+ initiatives have emerged, presenting an opportunity to pilot and compare different approaches to quantifying impacts on carbon emissions. This study (1) develops a Before-After-Control-Intervention (BACI) method to assess the effectiveness of these REDD+ initiatives; (2) compares the results at the meso (initiative) and micro (village) scales; and (3) compares BACI with the simpler Before-After (BA) results. Our study covers 23 subnational REDD+ initiatives in Brazil, Peru, Cameroon, Tanzania, Indonesia and Vietnam. As a proxy for deforestation, we use annual tree cover loss. We aggregate data into two periods (before and after the start of each initiative). Analysis using control areas (‘control-intervention’) suggests better REDD+ performance, although the effect is more pronounced at the micro than at the meso level. Yet, BACI requires more data than BA, and is subject to possible bias in the before period. Selection of proper control areas is vital, but at either scale is not straightforward. Low absolute deforestation numbers and peak years influence both our BA and BACI results. In principle, BACI is superior, with its potential to effectively control for confounding factors. We conclude that the more local the scale of performance assessment, the more relevant is the use of the BACI approach. For various reasons, we find overall minimal impact of REDD+ in reducing deforestation on the ground thus far. Incorporating results from micro and meso level monitoring into national reporting systems is important, since overall REDD+ impact depends on land use decisions on the ground.

Operative and nonoperative treatment of clavicle fractures in adults

PubMed Central

2012-01-01

Background and purpose Traditionally, clavicle fractures have been treated nonoperatively. However, many recent studies have concentrated on the results of operative treatment. We assessed and compared the outcomes of operative and nonoperative treatment for acute clavicle fractures in adults. Methods We performed a systematic search of the medical literature from 1966 until the end of March 2011. We included randomized controlled trials and controlled clinical trials comparing operative and nonoperative treatment and studies comparing different operative and nonoperative treatments. We required that there should be at least 30 adult patients and a follow-up of at least 6 months in each individual trial. We used the GRADE method to assess the quality of evidence. Results 6 randomized controlled trials (n = 631) and 7 controlled clinical trials (n = 559) were included. There was moderate-quality evidence (i.e. of grade B) (1) that surgery has considerable effectiveness on better function and less disability at short follow-up, (2) of similar risk of relatively mild complications after operative or nonoperative treatment, (3) that delayed union and nonunion were more common in patients who were treated nonoperatively than in those treated operatively, and (4) that the osteosynthesis method had no effect on the incidence of delayed union or nonunion. Only 1 controlled clinical trial was found on lateral clavicle fractures with very limited (grade D) evidence. Interpretation Patients treated operatively have slightly better function and less disability than those treated nonoperatively at short follow-up, but then the effectiveness diminishes and is weak at 6 months. The different operative techniques may not differ in effectiveness or in adverse effects, but the evidence is very limited or conflicting. Surgery could be considered for active patients who require recovery to the previous level of activity in the shortest possible time. PMID:22248169

Correction to: The effectiveness of a life style modification and peer support home blood pressure monitoring in control of hypertension: protocol for a cluster randomized controlled trial.

PubMed

Su, Tin Tin; Majid, Hazreen Abdul; Nahar, Azmi Mohamed; Azizan, Nurul Ain; Hairi, Farizah Mohd; Thangiah, Nithiah; Dahlui, Maznah; Bulgiba, Awang; Murray, Liam J

2017-11-06

After publication of the article [1], it has been brought to our attention that the methodology outlined in the original article was not able to be fully carried out. The article planned a two armed randomized control trial. However, due to a lower response than expected and one housing complex dropping out from the study, the method was changed to pre- and post-intervention with no control group. All other methods were conducted as outlined in the original article.

Controlling the perceived distance of an auditory object by manipulation of loudspeaker directivity.

PubMed

Laitinen, Mikko-Ville; Politis, Archontis; Huhtakallio, Ilkka; Pulkki, Ville

2015-06-01

This work presents a method to control the perceived distance of an auditory object by changing the directivity pattern of a loudspeaker and consequently the direct-to-reverberant ratio at the listening spot. Control of the directivity pattern is achieved by beamforming using a compact multi-driver loudspeaker unit. A small-sized cubic array consisting of six drivers is assembled, and per driver beamforming filters are derived from directional measurements of the array. The proposed method is evaluated using formal listening tests. The results show that the perceived distance can be controlled effectively by directivity pattern modification.

Effects of Edge Directions on the Structural Controllability of Complex Networks.

PubMed

Xiao, Yandong; Lao, Songyang; Hou, Lvlin; Small, Michael; Bai, Liang

2015-01-01

Recent advances indicate that assigning or reversing edge direction can significantly improve the structural controllability of complex networks. For directed networks, approaching the optimal structural controllability can be achieved by detecting and reversing certain "inappropriate" edge directions. However, the existence of multiple sets of "inappropriate" edge directions suggests that different edges have different effects on optimal controllability-that is, different combinations of edges can be reversed to achieve the same structural controllability. Therefore, we classify edges into three categories based on their direction: critical, redundant and intermittent. We then investigate the effects of changing these edge directions on network controllability, and demonstrate that the existence of more critical edge directions implies not only a lower cost of modifying inappropriate edges but also better controllability. Motivated by this finding, we present a simple edge orientation method aimed at producing more critical edge directions-utilizing only local information-which achieves near optimal controllability. Furthermore, we explore the effects of edge direction on the controllability of several real networks.

[Effect of schistosomiasis control strategy based on infection source control of Poyang Lake region in Yongxiu County promotion zone].

PubMed

Chen, Zhe; Rao, Xian-long; Li, Yi-feng; Gu, Xiao-nan; Xu, Mei-xin; Lin, Dan-dan

2015-12-01

To evaluate the effect of schistosomiasis control strategy with emphasis on infection source control in the Yongxiu County promotion zone of Poyang Lake region. The Wucheng Township of Yongxiu County was selected as the observation site, and the effect of the comprehensive control strategy was evaluated by using the method of field surveys combined with retrospective investigations. In 2010, there were 17 persons whose stool tests for schistosome infection were positive, and the number of calculated schistosomiasis patients was 2,331. The infection rate of cattle was 4.5%, and the area with infected Oncomelania hupensis snails was 10.00 hm². In 2011, the comprehensive control strategy was carried out, and in 2012, there were no cattle in the promotion zone. In 2013 and 2014, there were no schistosomiasis patients with positive stool tests. In 2014, no schistosome infected snails were found. The control strategy with emphasis on infection source control effectively controls the transmission of schistosomiasis in Yongxiu County promotion zone.

An Investigation of the Effectiveness of Increasing Academic Learning Time for College Undergraduate Students' Achievement in Kuwait

ERIC Educational Resources Information Center

Al-Shammari, Zaid; Mohammad, Anwar; Al-Shammari, Bandar

2010-01-01

The study investigated the effectiveness of increasing ALT for college students' achievement in Kuwait. In Phase 1, 37 students participated (22, experimental; 15, control); in Phase 2, 19 students participated (8, sub-experimental; 11, sub-control). Several experimental research methods used in conducting this study, including development of a…

Effect of a Universal Anxiety Prevention Programme (FRIENDS) on Children's Academic Performance: Results from a Randomised Controlled Trial

ERIC Educational Resources Information Center

Skryabina, Elena; Taylor, Gordon; Stallard, Paul

2016-01-01

Background: Evaluations of school-based anxiety prevention programmes have reported improvements in psychological functioning although little is known about their effect upon educational outcomes. Methods: One thousand three hundred and sixty-two children from 40 primary schools in England took part in the randomised controlled trial, Preventing…

Effects of Cognitive Enhancement Therapy on Employment Outcomes in Early Schizophrenia: Results from a 2-Year Randomized Trial

ERIC Educational Resources Information Center

Eack, Shaun M.; Hogarty, Gerard E.; Greenwald, Deborah P.; Hogarty, Susan S.; Keshavan, Matcheri S.

2011-01-01

Objective: To examine the effects of psychosocial cognitive rehabilitation on employment outcomes in a randomized controlled trial for individuals with early course schizophrenia. Method: Early course schizophrenia outpatients (N = 58) were randomly assigned to cognitive enhancement therapy (CET) or an enriched supportive therapy (EST) control and…

The Effectiveness of Picture Exchange Communication System (PECS) Training for Teachers of Children with Autism: A Pragmatic, Group Randomised Controlled Trial

ERIC Educational Resources Information Center

Howlin, Patricia; Gordon, R. Kate; Pasco, Greg; Wade, Angie; Charman, Tony

2007-01-01

Objective: To assess the effectiveness of expert training and consultancy for teachers of children with autism spectrum disorder in the use of the Picture Exchange Communication System (PECS). Method: Design: Group randomised, controlled trial (3 groups: immediate treatment, delayed treatment, no treatment). Participants: 84 elementary school…

Randomized Controlled Trial Examining the Effectiveness of a Tailored Self-Help Smoking-Cessation Intervention for Postsecondary Smokers

ERIC Educational Resources Information Center

Travis, Heather E.; Lawrance, Kelli-an G.

2009-01-01

Objective: Between September 2002 and February 2003, the authors assessed the effectiveness of a new, age-tailored, self-help smoking-cessation program for college students. Participants: College student smokers (N = 216) from 6 Ontario universities participated. Methods: The researchers used a randomized controlled trial with a 3-month telephone…

Evaluation and control of environmental corrosion for aluminum and steel alloys

NASA Technical Reports Server (NTRS)

Franklin, D. B.

1977-01-01

Corrosion protection systems for aerospace application and the effects of surface treatments and methods of controlling stress corrosion are evaluated. Chromate pigmented systems were found to be most effective for aluminum alloys; zinc-rich coatings gave the greatest protection to steel alloys. Various steel and aluminum alloys are rated for stress corrosion resistance.

Comparison of Address-based Sampling and Random-digit Dialing Methods for Recruiting Young Men as Controls in a Case-Control Study of Testicular Cancer Susceptibility

PubMed Central

Clagett, Bartholt; Nathanson, Katherine L.; Ciosek, Stephanie L.; McDermoth, Monique; Vaughn, David J.; Mitra, Nandita; Weiss, Andrew; Martonik, Rachel; Kanetsky, Peter A.

2013-01-01

Random-digit dialing (RDD) using landline telephone numbers is the historical gold standard for control recruitment in population-based epidemiologic research. However, increasing cell-phone usage and diminishing response rates suggest that the effectiveness of RDD in recruiting a random sample of the general population, particularly for younger target populations, is decreasing. In this study, we compared landline RDD with alternative methods of control recruitment, including RDD using cell-phone numbers and address-based sampling (ABS), to recruit primarily white men aged 18–55 years into a study of testicular cancer susceptibility conducted in the Philadelphia, Pennsylvania, metropolitan area between 2009 and 2012. With few exceptions, eligible and enrolled controls recruited by means of RDD and ABS were similar with regard to characteristics for which data were collected on the screening survey. While we find ABS to be a comparably effective method of recruiting young males compared with landline RDD, we acknowledge the potential impact that selection bias may have had on our results because of poor overall response rates, which ranged from 11.4% for landline RDD to 1.7% for ABS. PMID:24008901

Switched-Observer-Based Adaptive Neural Control of MIMO Switched Nonlinear Systems With Unknown Control Gains.

PubMed

Long, Lijun; Zhao, Jun

2017-07-01

In this paper, the problem of adaptive neural output-feedback control is addressed for a class of multi-input multioutput (MIMO) switched uncertain nonlinear systems with unknown control gains. Neural networks (NNs) are used to approximate unknown nonlinear functions. In order to avoid the conservativeness caused by adoption of a common observer for all subsystems, an MIMO NN switched observer is designed to estimate unmeasurable states. A new switched observer-based adaptive neural control technique for the problem studied is then provided by exploiting the classical average dwell time (ADT) method and the backstepping method and the Nussbaum gain technique. It effectively handles the obstacle about the coexistence of multiple Nussbaum-type function terms, and improves the classical ADT method, since the exponential decline property of Lyapunov functions for individual subsystems is no longer satisfied. It is shown that the technique proposed is able to guarantee semiglobal uniformly ultimately boundedness of all the signals in the closed-loop system under a class of switching signals with ADT, and the tracking errors converge to a small neighborhood of the origin. The effectiveness of the approach proposed is illustrated by its application to a two inverted pendulum system.

Fabrication and applications of electrets

NASA Technical Reports Server (NTRS)

Pillai, P. K. C.; Shriver, E. L.

1977-01-01

Permanently charged dielectrics can be made less expensively, faster, and more effectively using improved techniques and materials. Methods include charge injection, Tesla-coil charging, and molten spray. Possible uses include pollution control, low-power sensors, and illumination control.

MEMBRANES FOR DRINKING WATER TREATMENT

EPA Science Inventory

Various treatment technologies have proven effective in controlling halogenated disinfection by-products such as precursor removal and the use of alternative disinfectants. One of the most promising methods for halogenated by-product control includes removal of precursors before ...

Numerical Analysis on Seepage in the deep overburden CFRD

NASA Astrophysics Data System (ADS)

Zeyu, GUO; Junrui, CHAI; Yuan, QIN

2017-12-01

There are many problems in the construction of hydraulic structures on deep overburden because of its complex foundation structure and poor geological condition. Seepage failure is one of the main problems. The Combination of the seepage control system of the face rockfill dam and the deep overburden can effectively control the seepage of construction of the concrete face rockfill dam on the deep overburden. Widely used anti-seepage measures are horizontal blanket, waterproof wall, curtain grouting and so on, but the method, technique and its effect of seepage control still have many problems thus need further study. Due to the above considerations, Three-dimensional seepage field numerical analysis based on practical engineering case is conducted to study the seepage prevention effect under different seepage prevention methods, which is of great significance to the development of dam technology and the development of hydropower resources in China.

The effectiveness of module based on guided inquiry method to improve students’ logical thinking ability

NASA Astrophysics Data System (ADS)

Ash-Shiddieqy, M. H.; Suparmi, A.; Sunarno, W.

2018-04-01

The purpose of this research is to understand the effectiveness of module based on guided inquiry method to improve students’ logical thinking ability. This research only evaluate the students’ logical ability after follows the learning activities that used developed physics module based on guided inquiry method. After the learning activities, students This research method uses a test instrument that adapts TOLT instrument. There are samples of 68 students of grade XI taken from SMA Negeri 4 Surakarta.Based on the results of the research can be seen that in the experimental class and control class, the posttest value aspect of probabilistic reasoning has the highest value than other aspects, whereas the posttest value of the proportional reasoning aspect has the lowest value. The average value of N-gain in the experimental class is 0.39, while in the control class is 0.30. Nevertheless, the N-gain values obtained in the experimental class are larger than the control class, so the guided inquiry-based module is considered more effective for improving students’ logical thinking. Based on the data obtained from the research shows the modules available to help teachers and students in learning activities. The developed Physics module is integrated with every syntax present in guided inquiry method, so it can be used to improve students’ logical thinking ability.

Experiences in Tick Control by Acaricide in the Traditional Cattle Sector in Zambia and Burkina Faso: Possible Environmental and Public Health Implications.

PubMed

De Meneghi, Daniele; Stachurski, Frédéric; Adakal, Hassane

2016-01-01

Livestock, especially cattle, play a paramount role in agriculture production systems, particularly in poor countries throughout the world. Ticks and tick-borne diseases (TBDs) have an important impact on livestock and agriculture production in sub-Saharan Africa. The authors review the most common methods used for the control of ticks and TBDs. Special emphasis is given to the direct application of acaricides to the host animals. The possible environmental and public health adverse effects (i.e., risks for the workers, residues in the environment and in food products of animal origin) are mentioned. The authors present two case studies, describing different field experiences in controlling ticks in two African countries. In Zambia (Southern Africa), a strategic dipping regime was used to control Rhipicephalus appendiculatus ticks, vectors of theileriosis, a deadly disease affecting cattle in the traditional livestock sector in Southern Province. The dipping regime adopted allowed to reduce the tick challenge and cattle mortally rate and, at the same time, to employ less acaricide as compared to the intensive dipping used so far, without disrupting the building-up of enzootic stability. In Burkina Faso (West Africa), where dipping was never used for tick control, an acaricide footbath was employed as an alternative method to the traditional technique used locally (portable manual sprayers). This was developed from field observations on the invasion/attachment process of the Amblyomma variegatum ticks - vector of cowdriosis - on the animal hosts, leading to a control method aimed to kill ticks temporarily attached to the interdigital areas before their permanent attachment to the predilection sites. This innovative method has been overall accepted by the local farmers. It has the advantage of greatly reducing costs of treatments and has a minimal environmental impact, making footbath a sustainable and replicable method, adoptable also in other West African countries. Although the two methods described, developed in very different contexts, are not comparable - if public health and environmental implications are taken into account, if a balance among efficacy of the control method(s), cost-effectiveness and sustainability is reached - a way forward for the implementation of a One Health strategy can be set.

Autogenic-Feedback Training Exercise (AFTE) Method and System

NASA Technical Reports Server (NTRS)

Cowings, Patricia S. (Inventor)

1997-01-01

The Autogenic-Feedback Training Exercise (AFTE) method of the present invention is a combined application of physiologic and perceptual training techniques. such as autogenic therapy and biofeedback. This combined therapy approach produces a methodology that is appreciably more effective than either of the individual techniques used separately. The AFTE method enables sufficient magnitude of control necessary to significantly reduce the behavioral and physiologic reactions to severe environmental stressors. It produces learned effects that are persistent over time and are resistant to extinction and it can be administered in a short period of time. The AFTE method may be used efficiently in several applications, among which are the following: to improve pilot and crew performance during emergency flying conditions; to train people to prevent the occurrence of nausea and vomiting associated with motion and sea sickness, or morning sickness in early pregnancy; as a training method for preventing or counteracting air-sickness symptoms in high-performance military aircraft; for use as a method for cardiovascular training, as well as for multiple other autonomic responses, which may contribute to the alleviation of Space Motion Sickness (SMS) in astronauts and cosmonauts; training people suffering from migraine or tension headaches to control peripheral blood flow and reduce forehead and/or trapezius muscle tension; training elderly people suffering from fecal incontinence to control their sphincter muscles; training cancer patients to reduce the nauseagenic effects of chemotherapy; and training patients with Chronic Intestinal Pseudo-obstruction (CIP).

A Pilot Randomised Controlled Trial of a School-Based Resilience Intervention to Prevent Depressive Symptoms for Young Adolescents with Autism Spectrum Disorder: A Mixed Methods Analysis

ERIC Educational Resources Information Center

Mackay, Bethany A.; Shochet, Ian M.; Orr, Jayne A.

2017-01-01

Despite increased depression in adolescents with Autism Spectrum Disorder (ASD), effective prevention approaches for this population are limited. A mixed methods pilot randomised controlled trial (N = 29) of the evidence-based Resourceful Adolescent Program-Autism Spectrum Disorder (RAP-A-ASD) designed to prevent depression was conducted in…