21 CFR 514.117 - Adequate and well-controlled studies.

Code of Federal Regulations, 2013 CFR

2013-04-01

... experimental units. When the effect of such variables is accounted for by an appropriate design, and when... and well-controlled study should provide sufficient details of study design, conduct, and analysis to... the new animal drug used in the study. (4) The study uses a design that permits a valid comparison...

21 CFR 514.117 - Adequate and well-controlled studies.

Code of Federal Regulations, 2010 CFR

2010-04-01

... experimental units. When the effect of such variables is accounted for by an appropriate design, and when... and well-controlled study should provide sufficient details of study design, conduct, and analysis to... the new animal drug used in the study. (4) The study uses a design that permits a valid comparison...

Stated Choice design comparison in a developing country: recall and attribute nonattendance

PubMed Central

2014-01-01

Background Experimental designs constitute a vital component of all Stated Choice (aka discrete choice experiment) studies. However, there exists limited empirical evaluation of the statistical benefits of Stated Choice (SC) experimental designs that employ non-zero prior estimates in constructing non-orthogonal constrained designs. This paper statistically compares the performance of contrasting SC experimental designs. In so doing, the effect of respondent literacy on patterns of Attribute non-Attendance (ANA) across fractional factorial orthogonal and efficient designs is also evaluated. The study uses a ‘real’ SC design to model consumer choice of primary health care providers in rural north India. A total of 623 respondents were sampled across four villages in Uttar Pradesh, India. Methods Comparison of orthogonal and efficient SC experimental designs is based on several measures. Appropriate comparison of each design’s respective efficiency measure is made using D-error results. Standardised Akaike Information Criteria are compared between designs and across recall periods. Comparisons control for stated and inferred ANA. Coefficient and standard error estimates are also compared. Results The added complexity of the efficient SC design, theorised elsewhere, is reflected in higher estimated amounts of ANA among illiterate respondents. However, controlling for ANA using stated and inferred methods consistently shows that the efficient design performs statistically better. Modelling SC data from the orthogonal and efficient design shows that model-fit of the efficient design outperform the orthogonal design when using a 14-day recall period. The performance of the orthogonal design, with respect to standardised AIC model-fit, is better when longer recall periods of 30-days, 6-months and 12-months are used. Conclusions The effect of the efficient design’s cognitive demand is apparent among literate and illiterate respondents, although, more pronounced among illiterate respondents. This study empirically confirms that relaxing the orthogonality constraint of SC experimental designs increases the information collected in choice tasks, subject to the accuracy of the non-zero priors in the design and the correct specification of a ‘real’ SC recall period. PMID:25386388

A numerical study of mixing in supersonic combustors with hypermixing injectors

NASA Technical Reports Server (NTRS)

Lee, J.

1993-01-01

A numerical study was conducted to evaluate the performance of wall mounted fuel-injectors designed for potential Supersonic Combustion Ramjet (SCRAM-jet) engine applications. The focus of this investigation was to numerically simulate existing combustor designs for the purpose of validating the numerical technique and the physical models developed. Three different injector designs of varying complexity were studied to fully understand the computational implications involved in accurate predictions. A dual transverse injection system and two streamwise injector designs were studied. The streamwise injectors were designed with swept ramps to enhance fuel-air mixing and combustion characteristics at supersonic speeds without the large flow blockage and drag contribution of the transverse injection system. For this study, the Mass-Average Navier-Stokes equations and the chemical species continuity equations were solved. The computations were performed using a finite-volume implicit numerical technique and multiple block structured grid system. The interfaces of the multiple block structured grid systems were numerically resolved using the flux-conservative technique. Detailed comparisons between the computations and existing experimental data are presented. These comparisons show that numerical predictions are in agreement with the experimental data. These comparisons also show that a number of turbulence model improvements are needed for accurate combustor flowfield predictions.

A numerical study of mixing in supersonic combustors with hypermixing injectors

NASA Technical Reports Server (NTRS)

Lee, J.

1992-01-01

A numerical study was conducted to evaluate the performance of wall mounted fuel-injectors designed for potential Supersonic Combustion Ramjet (SCRAM-jet) engine applications. The focus of this investigation was to numerically simulate existing combustor designs for the purpose of validating the numerical technique and the physical models developed. Three different injector designs of varying complexity were studied to fully understand the computational implications involved in accurate predictions. A dual transverse injection system and two streamwise injector designs were studied. The streamwise injectors were designed with swept ramps to enhance fuel-air mixing and combustion characteristics at supersonic speeds without the large flow blockage and drag contribution of the transverse injection system. For this study, the Mass-Averaged Navier-Stokes equations and the chemical species continuity equations were solved. The computations were performed using a finite-volume implicit numerical technique and multiple block structured grid system. The interfaces of the multiple block structured grid systems were numerically resolved using the flux-conservative technique. Detailed comparisons between the computations and existing experimental data are presented. These comparisons show that numerical predictions are in agreement with the experimental data. These comparisons also show that a number of turbulence model improvements are needed for accurate combustor flowfield predictions.

The early development of stereotypy and self-injury: a review of research methods.

PubMed

Symons, F J; Sperry, L A; Dropik, P L; Bodfish, J W

2005-02-01

The origin and developmental course of stereotypic and self-injurious behaviour among individuals with developmental disabilities such as intellectual disability (ID) or pervasive development disorders such as autism is not well understood. Twelve studies designed to document the prevalence, nature, or development of stereotypic and/or self-injurious behaviour in children under 5 years of age and identified as at risk for developmental delay or disability were reviewed. Comparisons were made with similar studies with typically developing children. It appears that the onset of naturally occurring rhythmic motor stereotypies is delayed in young at-risk children, but that the sequencing may be similar. A very small database, differences in samples, measures, and designs limited the degree to which comparisons could be made across studies. Future work is needed based on appropriately designed prospective comparison studies and uniform quantitative measures to provide an empirical basis for new knowledge about the early development of one of the most serious behaviour disorders afflicting children with ID and related problems of development.

Cost studies for commercial fuselage crown designs

NASA Technical Reports Server (NTRS)

Walker, T. H.; Smith, P. J.; Truslove, G.; Willden, K. S.; Metschan, S. L.; Pfahl, C. L.

1991-01-01

Studies were conducted to evaluate the cost and weight potential of advanced composite design concepts in the crown region of a commercial transport. Two designs from each of three design families were developed using an integrated design-build team. A range of design concepts and manufacturing processes were included to allow isolation and comparison of cost centers. Detailed manufacturing/assembly plans were developed as the basis for cost estimates. Each of the six designs was found to have advantages over the 1995 aluminum benchmark in cost and weight trade studies. Large quadrant panels and cobonded frames were found to save significant assembly labor costs. Comparisons of high- and intermediate-performance fiber systems were made for skin and stringer applications. Advanced tow placement was found to be an efficient process for skin lay up. Further analysis revealed attractive processes for stringers and frames. Optimized designs were informally developed for each design family, combining the most attractive concepts and processes within that family. A single optimized design was selected as the most promising, and the potential for further optimization was estimated. Technical issues and barriers were identified.

78 FR 25710 - Applications for New Awards; Strengthening Institutions Program (SIP)

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-02

... priority in this notice: Carefully matched comparison group design means a type of quasi- experimental... notice). More specifically, it is a design in which project participants are matched with non... group study. When designing their study, applicants should consider participant characteristics relevant...

Graphic representation of data resulting from measurement comparison trials in cataract and refractive surgery.

PubMed

Krummenauer, Frank; Storkebaum, Kristin; Dick, H Burkhard

2003-01-01

The evaluation of new diagnostic measurement devices allows intraindividual comparison with an established standard method. However, reports in journal articles often omit the adequate incorporation of the intraindividual design into the graphic representation. This article illustrates the drawbacks and the possible erroneous conclusions caused by this misleading practice in terms of recent method comparison data resulting from axial length measurement in 220 consecutive patients by both applanation ultrasound and partial coherence interferometry. Graphic representation of such method comparison data should be based on boxplots for intraindividual differences or on Bland-Altman plots. Otherwise, severe deviations between the measurement devices could be erroneously ignored and false-positive conclusions on the concordance of the instruments could result. Graphic representation of method comparison data should sensitively incorporate the underlying study design for intraindividual comparison.

Reflections on experimental research in medical education.

PubMed

Cook, David A; Beckman, Thomas J

2010-08-01

As medical education research advances, it is important that education researchers employ rigorous methods for conducting and reporting their investigations. In this article we discuss several important yet oft neglected issues in designing experimental research in education. First, randomization controls for only a subset of possible confounders. Second, the posttest-only design is inherently stronger than the pretest-posttest design, provided the study is randomized and the sample is sufficiently large. Third, demonstrating the superiority of an educational intervention in comparison to no intervention does little to advance the art and science of education. Fourth, comparisons involving multifactorial interventions are hopelessly confounded, have limited application to new settings, and do little to advance our understanding of education. Fifth, single-group pretest-posttest studies are susceptible to numerous validity threats. Finally, educational interventions (including the comparison group) must be described in detail sufficient to allow replication.

A Comparison Study of Second-Order Screening Designs and Their Extension

DTIC Science & Technology

2013-12-01

H2 97 V. Nonlinear Screening Designs for Defense Testing: An Overview and Case Study 5.1 Introduction “Necessity is the Mother of Invention.” Plato is...involved concepts like design resolution, minimum aber- ration , power, the number of clear (non-confounded) effects, concepts like rotatability

76 FR 27637 - Supplemental Priorities for Discretionary Grant Programs

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-12

.... Interrupted time series design means a type of quasi-experimental study (as defined in this notice) in which... design is an adaptation of an interrupted time series design that relies on the comparison of treatment... notice), interrupted time series designs (as defined in this notice), or regression discontinuity designs...

A proposed model to conduct process and outcome evaluations and implementation research of child health programs in Africa using integrated community case management as an example.

PubMed

Diaz, Theresa; Guenther, Tanya; Oliphant, Nicholas P; Muñiz, Maria

2014-12-01

To use a newly devised set of criteria to review the study design and scope of collection of process, outcomes and contextual data for evaluations and implementation research of integrated community case management (iCCM) in Sub-Saharan African. We examined 24 program evaluations and implementation research studies of iCCM in sub-Saharan Africa conducted in the last 5 years (2008-2013), assessed the design used and categorized them according to whether or not they collected sufficient information to conduct process and outcome evaluations. Five of the 24 studies used a stepped wedge design and two were randomized control trials. The remaining 17 were quasi-experimental of which 10 had comparison areas; however, not all comparison areas had a pre and post household survey. With regard to process data, 22 of the studies collected sufficient information to report on implementation strength, and all, except one, could report on program implementation. Most common missing data elements were health facility treatments, service costs, and qualitative data to assess demand. For the measurement of program outcomes, 7 of the 24 studies had a year or less of implementation at scale before the endline survey, 6 of the household surveys did not collect point of service, 10 did not collect timeliness (care seeking within 24 hours of symptoms) and 12 did not have socioeconomic (SES) information. Among the 16 studies with comparison areas, only 5 randomly selected comparison areas, while 10 had appropriate comparison areas. Several evaluations were done too soon after implementation, lacked information on health facility treatments, costs, demand, timeliness or SES and/or did not have a counterfactual. We propose several study designs and minimal data elements to be collected to provide sufficient information to assess whether iCCM increased timely coverage of treatment for the neediest children in a cost-efficient manner.

A Comparison of Psychoanalytic Therapy and Cognitive Behavioral Therapy for Anxiety (Panic/Agoraphobia) and Personality Disorders (APD Study): Presentation of the RCT Study Design.

PubMed

Benecke, Cord; Huber, Dorothea; Staats, Hermann; Zimmermann, Johannes; Henkel, Miriam; Deserno, Heinrich; Wiegand-Grefe, Silke; Schauenburg, Henning

2016-09-01

Anxiety disorders, most notably panic disorders and agoraphobia, are common mental disorders, and there is a high comorbidity with personality disorders. Randomized controlled trails addressing this highly relevant group of patients are missing. The multicenter Anxiety and Personality Disorders (APD) study investigates 200 patients with panic disorder and/or agoraphobia with comorbid personality disorder in a randomized control-group comparison of psychoanalytic therapy (PT) and cognitive behavioral therapy (CBT), including 100 patients in each group. Each patient will be examined over a period of six years, regardless of the duration of the individual treatment. The main issues that are addressed in this study are the comparison of the efficacy of PT and CBT in this special patient population, the comparison of the sustainability of the effects of PT and CBT, the comparison of the long-term cost-benefit-ratios of PT and CBT as well as the investigation of prescriptive patient characteristics for individualized treatment recommendations (differential indication). The APD study compares efficacy, sustainability, and cost-benefit-ratios of CBT and PT for anxiety plus personality disorders in a randomized controlled trail. The study design meets the requirements for an efficacy study for PT, which were recently defined. Current Controlled Trials ISRCTN12449681.

78 FR 18710 - Applications for New Awards; Investing in Innovation Fund, Development Grants

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-27

... statistical controls for selection bias; (2) Quasi-experimental study (as defined in this notice) that meets... Act of 1965, as amended. Quasi-experimental design study means a study using a design that attempts to approximate an experimental design by identifying a comparison group that is similar to the treatment group in...

78 FR 25977 - Applications for New Awards; Investing in Innovation Fund, Scale-up Grants

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-03

... statistical controls for selection bias; (2) Quasi-experimental study (as defined in this notice) that meets... Act of 1965, as amended. Quasi-experimental design study means a study using a design that attempts to approximate an experimental design by identifying a comparison group that is similar to the treatment group in...

The Validity of the Comparative Interrupted Time Series Design for Evaluating the Effect of School-Level Interventions.

PubMed

Jacob, Robin; Somers, Marie-Andree; Zhu, Pei; Bloom, Howard

2016-06-01

In this article, we examine whether a well-executed comparative interrupted time series (CITS) design can produce valid inferences about the effectiveness of a school-level intervention. This article also explores the trade-off between bias reduction and precision loss across different methods of selecting comparison groups for the CITS design and assesses whether choosing matched comparison schools based only on preintervention test scores is sufficient to produce internally valid impact estimates. We conduct a validation study of the CITS design based on the federal Reading First program as implemented in one state using results from a regression discontinuity design as a causal benchmark. Our results contribute to the growing base of evidence regarding the validity of nonexperimental designs. We demonstrate that the CITS design can, in our example, produce internally valid estimates of program impacts when multiple years of preintervention outcome data (test scores in the present case) are available and when a set of reasonable criteria are used to select comparison organizations (schools in the present case). © The Author(s) 2016.

A comparison of arrow, trapezoidal and M wing concepts using a Mach 2 supersonic cruise transport mission

NASA Technical Reports Server (NTRS)

Martin, Glenn L.; Tice, David C.; Marcum, Don C., Jr.; Seidel, Jonathan A.

1991-01-01

The present analytic study of the potential performance of SST configurations radically differing from arrow-winged designs in lifting surface planform geometry gives attention to trapezoidal-wing and M-wing configurations; the trapezoidal wing is used as the baseline in the performance comparisons. The design mission was all-supersonic (Mach 2), carrying 248 passengers over a 5500 nautical-mile range. Design constraints encompassed approach speed, TO&L field length, and engine-out second-segment climb and missed-approach performance. Techniques for improving these configurations are discussed.

Comparison of several asphalt design methods.

DOT National Transportation Integrated Search

1998-01-01

This laboratory study compared several methods of selecting the optimum asphalt content of surface mixes. Six surface mixes were tested using the 50-blow Marshall design, the 75-blow Marshall design, two brands of SHRP gyratory compactors, and the U....

Numerical aerodynamic simulation facility preliminary study, volume 2 and appendices

NASA Technical Reports Server (NTRS)

1977-01-01

Data to support results obtained in technology assessment studies are presented. Objectives, starting points, and future study tasks are outlined. Key design issues discussed in appendices include: data allocation, transposition network design, fault tolerance and trustworthiness, logic design, processing element of existing components, number of processors, the host system, alternate data base memory designs, number representation, fast div 521 instruction, architectures, and lockstep array versus synchronizable array machine comparison.

A Low-Signal-to-Noise-Ratio Sensor Framework Incorporating Improved Nighttime Capabilities in DIRSIG

NASA Astrophysics Data System (ADS)

Rizzuto, Anthony P.

When designing new remote sensing systems, it is difficult to make apples-to-apples comparisons between designs because of the number of sensor parameters that can affect the final image. Using synthetic imagery and a computer sensor model allows for comparisons to be made between widely different sensor designs or between competing design parameters. Little work has been done in fully modeling low-SNR systems end-to-end for these types of comparisons. Currently DIRSIG has limited capability to accurately model nighttime scenes under new moon conditions or near large cities. An improved DIRSIG scene modeling capability is presented that incorporates all significant sources of nighttime radiance, including new models for urban glow and airglow, both taken from the astronomy community. A low-SNR sensor modeling tool is also presented that accounts for sensor components and noise sources to generate synthetic imagery from a DIRSIG scene. The various sensor parameters that affect SNR are discussed, and example imagery is shown with the new sensor modeling tool. New low-SNR detectors have recently been designed and marketed for remote sensing applications. A comparison of system parameters for a state-of-the-art low-SNR sensor is discussed, and a sample design trade study is presented for a hypothetical scene and sensor.

The Design of Time-Series Comparisons under Resource Constraints.

ERIC Educational Resources Information Center

Willemain, Thomas R.; Hartunian, Nelson S.

1982-01-01

Two methods for dividing an interrupted time-series study between baseline and experimental phases when study resources are limited are compared. In fixed designs, the baseline duration is predetermined. In flexible designs the baseline duration is contingent on remaining resources and the match of results to prior expectations of the evaluator.…

76 FR 32171 - Applications for New Awards; Investing in Innovation Fund

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-03

... conflict of interest. Interrupted time series design \\5\\ means a type of quasi- experimental study in... single case design is an adaptation of an interrupted time series design that relies on the comparison of...), interrupted time series designs (as defined in this notice), or regression discontinuity designs (as defined...

76 FR 32159 - Applications for New Awards; Investing in Innovation Fund

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-03

... conflict of interest. Interrupted time series design \\5\\ means a type of quasi- experimental study in which... design is an adaptation of an interrupted time series design that relies on the comparison of treatment...), interrupted time series designs (as defined in this notice), or regression discontinuity designs (as defined...

Content Analysis of Introductory Interior Design College Textbooks: A Study Revisited

ERIC Educational Resources Information Center

Temple, Julie A.; Potthoff, Joy K.

2013-01-01

Introductory interior design texts adopted by design educators present information relevant to both historical and contemporary issues in interior design. According to one author, they provide a "survey of the field of interior design as it now exists" (Pile, 2007). A comparison of the content of contemporary texts with those of more…

Comparison of Designer's Design Thinking Modes in Digital and Traditional Sketches

ERIC Educational Resources Information Center

Wu, Jun-Chieh; Chen, Cheng-Chi; Chen, Hsin-Chia

2012-01-01

The internal design thinking behaviour of designers in the concept development has been an important issue of cognitive psychology. In this study, the design thinking process designers have in applying digital media and traditional paper in the early concept development stage was explored. Special focus was made on the structure and procedure of…

Statistics attack on `quantum private comparison with a malicious third party' and its improvement

NASA Astrophysics Data System (ADS)

Gu, Jun; Ho, Chih-Yung; Hwang, Tzonelih

2018-02-01

Recently, Sun et al. (Quantum Inf Process:14:2125-2133, 2015) proposed a quantum private comparison protocol allowing two participants to compare the equality of their secrets via a malicious third party (TP). They designed an interesting trap comparison method to prevent the TP from knowing the final comparison result. However, this study shows that the malicious TP can use the statistics attack to reveal the comparison result. A simple modification is hence proposed to solve this problem.

Assessing Operation Purple: A Program Evaluation of a Summer Camp for Military Youth

DTIC Science & Technology

2012-01-01

However, it should be noted that the four FOCUS studies employed evaluation designs with no control or comparison group . Furthermore, despite...evaluation design was more robust than other military youth program evaluations that do not have a control or comparison group (Beardslee, Lester, et al...Operation Purple: A Program Evaluation of a Summer Camp for Military Youth camp group ); the remaining group formed the no-camp, or control , group . We

Is the linear modeling technique good enough for optimal form design? A comparison of quantitative analysis models.

PubMed

Lin, Yang-Cheng; Yeh, Chung-Hsing; Wang, Chen-Cheng; Wei, Chun-Chun

2012-01-01

How to design highly reputable and hot-selling products is an essential issue in product design. Whether consumers choose a product depends largely on their perception of the product image. A consumer-oriented design approach presented in this paper helps product designers incorporate consumers' perceptions of product forms in the design process. The consumer-oriented design approach uses quantification theory type I, grey prediction (the linear modeling technique), and neural networks (the nonlinear modeling technique) to determine the optimal form combination of product design for matching a given product image. An experimental study based on the concept of Kansei Engineering is conducted to collect numerical data for examining the relationship between consumers' perception of product image and product form elements of personal digital assistants (PDAs). The result of performance comparison shows that the QTTI model is good enough to help product designers determine the optimal form combination of product design. Although the PDA form design is used as a case study, the approach is applicable to other consumer products with various design elements and product images. The approach provides an effective mechanism for facilitating the consumer-oriented product design process.

Is the Linear Modeling Technique Good Enough for Optimal Form Design? A Comparison of Quantitative Analysis Models

PubMed Central

Lin, Yang-Cheng; Yeh, Chung-Hsing; Wang, Chen-Cheng; Wei, Chun-Chun

2012-01-01

How to design highly reputable and hot-selling products is an essential issue in product design. Whether consumers choose a product depends largely on their perception of the product image. A consumer-oriented design approach presented in this paper helps product designers incorporate consumers' perceptions of product forms in the design process. The consumer-oriented design approach uses quantification theory type I, grey prediction (the linear modeling technique), and neural networks (the nonlinear modeling technique) to determine the optimal form combination of product design for matching a given product image. An experimental study based on the concept of Kansei Engineering is conducted to collect numerical data for examining the relationship between consumers' perception of product image and product form elements of personal digital assistants (PDAs). The result of performance comparison shows that the QTTI model is good enough to help product designers determine the optimal form combination of product design. Although the PDA form design is used as a case study, the approach is applicable to other consumer products with various design elements and product images. The approach provides an effective mechanism for facilitating the consumer-oriented product design process. PMID:23258961

ELECTROFISHING IN BOATABLE RIVERS: DOES SAMPLING DESIGN AFFECT BIOASSESSMENT METRICS?

EPA Science Inventory

The accurate bioassessment of boatable rivers using fish assemblage data requires that a representative sample of the assemblage be collected. In this study, data were collected using an electrofishing design that permitted comparisons of the effects of designs and distances on ...

Facilitating mental health help-seeking by young adults with a dedicated online program: a feasibility study of Link

PubMed Central

Kauer, Sylvia D; Buhagiar, Kerrie; Blake, Victoria; Cotton, Sue; Sanci, Lena

2017-01-01

Objective To explore the feasibility of a dedicated online youth mental health help-seeking intervention and to evaluate using a randomised controlled trial (RCT) study design in order to identify any modifications needed before commencement of the full-scale RCT. Design A pilot RCT with 1:1 randomisation to either the intervention or comparison arm. Setting An online study conducted Australia-wide. Participants 18–25 year olds living in Australia were recruited via social media. Intervention Link is a dedicated online mental health help-seeking navigation tool that matches user’s mental health issues, severity and service-type preferences (online, phone and face-to-face) with appropriate youth-friendly services. The comparison arm was usual help-seeking strategies with a link to Google.com. Main outcome measures The primary outcome was the number of acceptability and feasibility criteria successfully met. Intervention and study design acceptability and feasibility were assessed by nine criteria. Secondary outcomes, via online surveys (at baseline, 1 week and 1 month) measured service use, help-seeking intentions, psychological distress, barriers to help-seeking, attitudes towards mental health help-seeking, mental health literacy, satisfaction and trust. Results Fifty-one participants were randomised (intervention: n=24; comparison: n=27). Three out of four of the intervention and two out of five of the study design criteria were met. Unmet criteria could be addressed by modifications to the study design. Qualitative analysis demonstrated that Link was useful to participants and may have increased their positive experiences towards help-seeking. There were no observable differences between arms in any outcome measures and no harms were detected. Conclusion Generally, the Link intervention and study design were acceptable and feasible with modifications suggested for the four out of nine unmet criteria. The main trial will hence have shorter surveys and a simpler recruitment process, use positive affect as the primary outcome and will not link to Google.com for the comparison arm. Trial registration number Australian New Zealand Clinical Trials Registry, ACTRN12614000386639. PMID:28694345

A Comparison of Methods to Test for Mediation in Multisite Experiments

ERIC Educational Resources Information Center

Pituch, Keenan A.; Whittaker, Tiffany A.; Stapleton, Laura M.

2005-01-01

A Monte Carlo study extended the research of MacKinnon, Lockwood, Hoffman, West, and Sheets (2002) for single-level designs by examining the statistical performance of four methods to test for mediation in a multilevel experimental design. The design studied was a two-group experiment that was replicated across several sites, included a single…

Investigating Children's Abilities to Count and Make Quantitative Comparisons

ERIC Educational Resources Information Center

Lee, Joohi; Md-Yunus, Sham'ah

2016-01-01

This study was designed to investigate children's abilities to count and make quantitative comparisons. In addition, this study utilized reasoning questions (i.e., how did you know?). Thirty-four preschoolers, mean age 4.5 years old, participated in the study. According to the results, 89% of the children (n = 30) were able to do rote counting and…

A comparison of the accuracy of the smart sock system to force platform and optical system for measurement of temporal parameters of locomotion

NASA Astrophysics Data System (ADS)

Oks, A.; Katashev, A.; Bernans, E.; Abolins, V.

2017-10-01

The aim of the study was to present a new DAid®Pressure Sock System for feet locomotion monitoring and to verify it’s temporal characteristics by data comparison with the same obtained by two other widely used methods as reference. Designed system is based on sensors which can be knitted directly in the garment or hosiery items. DAid®Pressure Sock System was created for sport and medical applications. Comparison of temporal characteristics of different types of locomotion, obtained using designed system and reference devises, showed good agreement between data.

Order of stimulus presentation influences children's acquisition in receptive identification tasks.

PubMed

Petursdottir, Anna Ingeborg; Aguilar, Gabriella

2016-03-01

Receptive identification is usually taught in matching-to-sample format, which entails the presentation of an auditory sample stimulus and several visual comparison stimuli in each trial. Conflicting recommendations exist regarding the order of stimulus presentation in matching-to-sample trials. The purpose of this study was to compare acquisition in receptive identification tasks under 2 conditions: when the sample was presented before the comparisons (sample first) and when the comparisons were presented before the sample (comparison first). Participants included 4 typically developing kindergarten-age boys. Stimuli, which included birds and flags, were presented on a computer screen. Acquisition in the 2 conditions was compared in an adapted alternating-treatments design combined with a multiple baseline design across stimulus sets. All participants took fewer trials to meet the mastery criterion in the sample-first condition than in the comparison-first condition. © 2015 Society for the Experimental Analysis of Behavior.

Operations analysis (study 2.1). Payload designs for space servicing, addendum

NASA Technical Reports Server (NTRS)

Wolfe, R. R.

1974-01-01

Space replaceable units and payload configurations are revised to reflect increased levels of redundancy to be more consistent with current design practices. A reassessment of expendable payload design reliabilities was performed to provide a common basis for comparison with space serviceable configurations.

Investigation, comparison and design of chambers used in centrifugal partition chromatography on the basis of flow pattern and separation experiments.

PubMed

Schwienheer, C; Merz, J; Schembecker, G

2015-04-17

In centrifugal partition chromatography (CPC) the separation efficiency is mainly influenced by the hydrodynamic of mobile and stationary phase in the chambers. Thus, the hydrodynamic has to be investigated and understood in order to enhance a CPC separation run. Different chamber geometries have been developed in the past and the influence of several phase systems and CPC operating conditions were investigated for these chambers. However, a direct comparison between the different chamber types has not been performed yet. In order to investigate the direct influence of the chamber design on the hydrodynamic, several chamber designs - partially similar in geometry to commercial available designs - are investigated under standardized conditions in the present study. The results show the influence of geometrical aspects of the chamber design on the hydrodynamic and therewith, on the separation efficiency. As a conclusion of the present study, some ideas for an optimal chamber design for laboratory and industrial purpose are proposed. Copyright © 2015 Elsevier B.V. All rights reserved.

Questionnaire Design in Broad-Based Evaluation Studies: Letting Someone Else Collect Comparison Group Data.

ERIC Educational Resources Information Center

Clark, Sheldon B.; Boser, Judith A.

A context in which existing items may provide a convenient source of questions for questionnaires was explored through a case study making use of existing comparison groups. Two programs at Oak Ridge Associated Universities (ORAU), the Science and Engineering Research Semester (SERS) and the Laboratory Graduate Research Participation (Lab Grad)…

Initial Field Testing for Forest Tree Improvement

Treesearch

C. B. Briscoe

1963-01-01

Initial field testing for forest tree improvement is essentially a comparison of genetic groups whether the level of comparison is of species, provenances, or individual trees. A good study design should be as economical as possible, for a given precision, and must be accurate. The latter is simply obtained by restricting the study to a specified set of conditions,...

Apprenticeship, education, and technology: Children as oldtimers and newcomers to the culture of learning through design

NASA Astrophysics Data System (ADS)

Ching, Cynthia Carter

This study deals with the construct of apprenticeship, a well-documented phenomena in anthropological and cultural studies, but which is treated here in unique ways. Whereas most existing work examines apprenticeship among adults in traditional vocational settings, this research is situated among a community of fourth and fifth grade schoolchildren with different levels of previous experience "learning through design" and programming science simulations, thus making them relative oldtimers and newcomers to the culture and practices of design. This work examines teams of children as they create computer simulations, and documents the practices that characterize their apprenticeship to one another. This research also describes how children conceptualize their own roles as newcomers or oldtimers to design. Finally, this study investigates how cognitive benefits realized in an apprenticeship environment are distinctive from that in non-apprenticeship classroom communities, due to the addition of a comparison group of fourth and fifth grade students all engaged in learning through design for the first time. Results reveal that design apprenticeship among schoolchildren shares some crucial characteristics with vocational apprenticeships. Oldtimers initially break down tasks into component parts for newcomers to perform, newcomers move from peripheral to fuller participation in the design process as the project progresses, and tacit pedagogical interactions initiated by oldtimers are intimately tied to the immediate design context on a day-to-day basis. Oldtimers are also more reflective about their interactions with other designers, and they have a more differentiated view of the design process as a whole, than newcomers or comparison first-time designers. The learning benefits realized in an apprenticeship environment are characterized not by a significant difference over the comparison class in the amount of science content or programming code students mastered, but rather in the extent to which students in the apprenticeship classroom are better able to use the context of design to help them represent science knowledge in a systemic manner. The results of this study have implications for broadening the accepted definitions of "apprenticeship" in the literature, curriculum design and implementation of design-based learning, and pedagogy and policy for the technology-infused classroom.

Applying Knowledge of Quantitative Design and Analysis

ERIC Educational Resources Information Center

Baskas, Richard S.

2011-01-01

This study compared and contrasted two quantitative scholarly articles in relation to their research designs. Their designs were analyzed by the comparison of research references and research specific vocabulary to describe how various research methods were used. When researching and analyzing quantitative scholarly articles, it is imperative to…

Homeostasis of Complementary Pair Theory: Ecological Comparisons in Diverse Universal Design for Learning Environments

ERIC Educational Resources Information Center

Ianneo, Brittany

2014-01-01

Accommodation~assimilation relations were theorized by Kelso and Engstrom (2006) as independent and dependent complementary pairs. This study defined relationships between organisms that experienced complementary interactions of accommodation~assimilation in diverse ecologies designed with universal design for learning environments (UDLE) compared…

Applying Knowledge of Qualitative Design and Analysis

ERIC Educational Resources Information Center

Baskas, Richard S.

2011-01-01

This study compared and contrasted two qualitative scholarly articles in relation to their research designs. Their designs were analyzed by the comparison of research references and research specific vocabulary to describe how various research methods were used. When researching and analyzing qualitative scholarly articles, it is imperative to…

Leveraging Failure in Design Research

ERIC Educational Resources Information Center

Lobato, Joanne; Walters, C. David; Hohensee, Charles; Gruver, John; Diamond, Jaime Marie

2015-01-01

Even in the resource-rich, more ideal conditions of many design-based classroom interventions, unexpected events can lead to disappointing results in student learning. However, if later iterations in a design research study are more successful, the previous failures can provide opportunities for comparisons to reveal subtle differences in…

Power of Models in Longitudinal Study: Findings from a Full-Crossed Simulation Design

ERIC Educational Resources Information Center

Fang, Hua; Brooks, Gordon P.; Rizzo, Maria L.; Espy, Kimberly Andrews; Barcikowski, Robert S.

2009-01-01

Because the power properties of traditional repeated measures and hierarchical multivariate linear models have not been clearly determined in the balanced design for longitudinal studies in the literature, the authors present a power comparison study of traditional repeated measures and hierarchical multivariate linear models under 3…

Ocean power technology design optimization

DOE PAGES

van Rij, Jennifer; Yu, Yi -Hsiang; Edwards, Kathleen; ...

2017-07-18

For this study, the National Renewable Energy Laboratory and Ocean Power Technologies (OPT) conducted a collaborative code validation and design optimization study for OPT's PowerBuoy wave energy converter (WEC). NREL utilized WEC-Sim, an open-source WEC simulator, to compare four design variations of OPT's PowerBuoy. As an input to the WEC-Sim models, viscous drag coefficients for the PowerBuoy floats were first evaluated using computational fluid dynamics. The resulting WEC-Sim PowerBuoy models were then validated with experimental power output and fatigue load data provided by OPT. The validated WEC-Sim models were then used to simulate the power performance and loads for operationalmore » conditions, extreme conditions, and directional waves, for each of the four PowerBuoy design variations, assuming the wave environment of Humboldt Bay, California. And finally, ratios of power-to-weight, power-to-fatigue-load, power-to-maximum-extreme-load, power-to-water-plane-area, and power-to-wetted-surface-area were used to make a final comparison of the potential PowerBuoy WEC designs. Lastly, the design comparison methodologies developed and presented in this study are applicable to other WEC devices and may be useful as a framework for future WEC design development projects.« less

Ocean power technology design optimization

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

van Rij, Jennifer; Yu, Yi -Hsiang; Edwards, Kathleen

For this study, the National Renewable Energy Laboratory and Ocean Power Technologies (OPT) conducted a collaborative code validation and design optimization study for OPT's PowerBuoy wave energy converter (WEC). NREL utilized WEC-Sim, an open-source WEC simulator, to compare four design variations of OPT's PowerBuoy. As an input to the WEC-Sim models, viscous drag coefficients for the PowerBuoy floats were first evaluated using computational fluid dynamics. The resulting WEC-Sim PowerBuoy models were then validated with experimental power output and fatigue load data provided by OPT. The validated WEC-Sim models were then used to simulate the power performance and loads for operationalmore » conditions, extreme conditions, and directional waves, for each of the four PowerBuoy design variations, assuming the wave environment of Humboldt Bay, California. And finally, ratios of power-to-weight, power-to-fatigue-load, power-to-maximum-extreme-load, power-to-water-plane-area, and power-to-wetted-surface-area were used to make a final comparison of the potential PowerBuoy WEC designs. Lastly, the design comparison methodologies developed and presented in this study are applicable to other WEC devices and may be useful as a framework for future WEC design development projects.« less

Conceptual Design of Environmentally Friendly Rotorcraft - A Comparison of NASA and ONERA Approaches

NASA Technical Reports Server (NTRS)

Russell, Carl; Basset, Pierre-Marie

2015-01-01

In 2011, a task was initiated under the US-French Project Agreement on rotorcraft studies to collaborate on design methodologies for environmentally friendly rotorcraft. This paper summarizes the efforts of that collaboration. The French and US aerospace agencies, ONERA and NASA, have their own software toolsets and approaches to rotorcraft design. The first step of this research effort was to understand how rotorcraft impact the environment, with the initial focus on air pollution. Second, similar baseline helicopters were developed for a passenger transport mission, using NASA and ONERA rotorcraft design software tools. Comparisons were made between the designs generated by the two tools. Finally, rotorcraft designs were generated targeting reduced environmental impact. The results show that a rotorcraft design that targets reduced environmental impact can be significantly different than one that targets traditional cost drivers, such as fuel burn and empty weight.

76 FR 9331 - Professional Development for Arts Educators Program; Office of Innovation and Improvement...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-17

... adaptation of an interrupted time series design that relies on the comparison of treatment effects on a... group designs (as defined in this notice), interrupted time series designs (as defined in this notice... series design means a type of quasi-experimental study (as defined in this notice) in which the outcome...

Establishing Equivalence: Methodological Progress in Group-Matching Design and Analysis

ERIC Educational Resources Information Center

Kover, Sara T.; Atwood, Amy K.

2013-01-01

This methodological review draws attention to the challenges faced by intellectual and developmental disabilities researchers in the appropriate design and analysis of group comparison studies. We provide a brief overview of matching methodologies in the field, emphasizing group-matching designs used in behavioral research on cognition and…

Designing Online Interaction to Address Disciplinary Competencies: A Cross-Country Comparison of Faculty Perspectives

ERIC Educational Resources Information Center

Barberà, Elena; Layne, Ludmila; Gunawardena, Charlotte N.

2014-01-01

This study was conducted at colleges in three countries (United States, Venezuela, and Spain) and across three academic disciplines (engineering, education, and business), to examine how experienced faculty define competencies for their discipline, and design instructional interaction for online courses. A qualitative research design employing…

International Students' College Choice is Different!

ERIC Educational Resources Information Center

Alfattal, Eyad

2017-01-01

Purpose: The purpose of this paper is to evaluate the needs and aspirations of international students studying at a comprehensive university campus in the USA in comparison to domestic students represented by factors that drive students' college choice. Design/methodology/approach: The study opted for a survey design through questionnaire and…

Rain fall data for the design of sewer pipe systems

NASA Astrophysics Data System (ADS)

Arnell, V.

1982-03-01

A comparison of designs of sewer pipes for different types of rainfall data is presented. Local coefficients were evaluated from an 18-year historical rainfall record for the following design storms: The Average-Intensity-Duration Design Storm, The Chicago Design Storm, The Sifalda Design Storm, The Illinois State Water Survey Design Storm, and The Flood Studies Report Design Storm. Historical rainfalls as well as the above design storms were used for the calculations of peak-flow values.

Addiction and "Generation Me:" Narcissistic and Prosocial Behaviors of Adolescents with Substance Dependency Disorder in Comparison to Normative Adolescents

ERIC Educational Resources Information Center

Carter, Rebecca R.; Johnson, Shannon M.; Exline, Julie J.; Post, Stephen G.; Pagano, Maria E.

2012-01-01

The purpose of this study is to explore narcissistic and prosocial behaviors as reported by adolescents with and without substance dependency disorder (SDD). This study employs a quasi-experimental design using SDD adolescents compared with two normative samples of adolescents. In comparison to normative adolescents, adolescents with SDD were…

Multidisciplinary Approach to Aerospike Nozzle Design

NASA Technical Reports Server (NTRS)

Korte, J. J.; Salas, A. O.; Dunn, H. J.; Alexandrov, N. M.; Follett, W. W.; Orient, G. E.; Hadid, A. H.

1997-01-01

A model of a linear aerospike rocket nozzle that consists of coupled aerodynamic and structural analyses has been developed. A nonlinear computational fluid dynamics code is used to calculate the aerodynamic thrust, and a three-dimensional finite-element model is used to determine the structural response and weight. The model will be used to demonstrate multidisciplinary design optimization (MDO) capabilities for relevant engine concepts, assess performance of various MDO approaches, and provide a guide for future application development. In this study, the MDO problem is formulated using the multidisciplinary feasible (MDF) strategy. The results for the MDF formulation are presented with comparisons against separate aerodynamic and structural optimized designs. Significant improvements are demonstrated by using a multidisciplinary approach in comparison with the single-discipline design strategy.

Facilitating mental health help-seeking by young adults with a dedicated online program: a feasibility study of Link.

PubMed

Kauer, Sylvia D; Buhagiar, Kerrie; Blake, Victoria; Cotton, Sue; Sanci, Lena

2017-07-09

To explore the feasibility of a dedicated online youth mental health help-seeking intervention and to evaluate using a randomised controlled trial (RCT) study design in order to identify any modifications needed before commencement of the full-scale RCT. A pilot RCT with 1:1 randomisation to either the intervention or comparison arm. An online study conducted Australia-wide. 18-25 year olds living in Australia were recruited via social media. Link is a dedicated online mental health help-seeking navigation tool that matches user's mental health issues, severity and service-type preferences (online, phone and face-to-face) with appropriate youth-friendly services. The comparison arm was usual help-seeking strategies with a link to Google.com. The primary outcome was the number of acceptability and feasibility criteria successfully met. Intervention and study design acceptability and feasibility were assessed by nine criteria. Secondary outcomes, via online surveys (at baseline, 1 week and 1 month) measured service use, help-seeking intentions, psychological distress, barriers to help-seeking, attitudes towards mental health help-seeking, mental health literacy, satisfaction and trust. Fifty-one participants were randomised (intervention: n=24; comparison: n=27). Three out of four of the intervention and two out of five of the study design criteria were met. Unmet criteria could be addressed by modifications to the study design. Qualitative analysis demonstrated that Link was useful to participants and may have increased their positive experiences towards help-seeking. There were no observable differences between arms in any outcome measures and no harms were detected. Generally, the Link intervention and study design were acceptable and feasible with modifications suggested for the four out of nine unmet criteria. The main trial will hence have shorter surveys and a simpler recruitment process, use positive affect as the primary outcome and will not link to Google.com for the comparison arm. Australian New Zealand Clinical Trials Registry, ACTRN12614000386639. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

A Virtual Environment System for the Comparison of Dome and HMD Systems

NASA Technical Reports Server (NTRS)

Chen, Jian; Harm, Deboran L.; Loftin, R. Bowen; Lin, Ching-yao; Leiss, Ernst L.

2002-01-01

For effective astronaut training applications, choosing the right display devices to present images is crucial. In order to assess what devices are appropriate, it is important to design a successful virtual environment for a comparison study of the display devices. We present a comprehensive system for the comparison of Dome and head-mounted display (HMD) systems. In particular, we address interactions techniques and playback environments.

Statistical power as a function of Cronbach alpha of instrument questionnaire items.

PubMed

Heo, Moonseong; Kim, Namhee; Faith, Myles S

2015-10-14

In countless number of clinical trials, measurements of outcomes rely on instrument questionnaire items which however often suffer measurement error problems which in turn affect statistical power of study designs. The Cronbach alpha or coefficient alpha, here denoted by C(α), can be used as a measure of internal consistency of parallel instrument items that are developed to measure a target unidimensional outcome construct. Scale score for the target construct is often represented by the sum of the item scores. However, power functions based on C(α) have been lacking for various study designs. We formulate a statistical model for parallel items to derive power functions as a function of C(α) under several study designs. To this end, we assume fixed true score variance assumption as opposed to usual fixed total variance assumption. That assumption is critical and practically relevant to show that smaller measurement errors are inversely associated with higher inter-item correlations, and thus that greater C(α) is associated with greater statistical power. We compare the derived theoretical statistical power with empirical power obtained through Monte Carlo simulations for the following comparisons: one-sample comparison of pre- and post-treatment mean differences, two-sample comparison of pre-post mean differences between groups, and two-sample comparison of mean differences between groups. It is shown that C(α) is the same as a test-retest correlation of the scale scores of parallel items, which enables testing significance of C(α). Closed-form power functions and samples size determination formulas are derived in terms of C(α), for all of the aforementioned comparisons. Power functions are shown to be an increasing function of C(α), regardless of comparison of interest. The derived power functions are well validated by simulation studies that show that the magnitudes of theoretical power are virtually identical to those of the empirical power. Regardless of research designs or settings, in order to increase statistical power, development and use of instruments with greater C(α), or equivalently with greater inter-item correlations, is crucial for trials that intend to use questionnaire items for measuring research outcomes. Further development of the power functions for binary or ordinal item scores and under more general item correlation strutures reflecting more real world situations would be a valuable future study.

Matched Comparison Group Design Standards in Systematic Reviews of Early Childhood Interventions.

PubMed

Thomas, Jaime; Avellar, Sarah A; Deke, John; Gleason, Philip

2017-06-01

Systematic reviews assess the quality of research on program effectiveness to help decision makers faced with many intervention options. Study quality standards specify criteria that studies must meet, including accounting for baseline differences between intervention and comparison groups. We explore two issues related to systematic review standards: covariate choice and choice of estimation method. To help systematic reviews develop/refine quality standards and support researchers in using nonexperimental designs to estimate program effects, we address two questions: (1) How well do variables that systematic reviews typically require studies to account for explain variation in key child and family outcomes? (2) What methods should studies use to account for preexisting differences between intervention and comparison groups? We examined correlations between baseline characteristics and key outcomes using Early Childhood Longitudinal Study-Birth Cohort data to address Question 1. For Question 2, we used simulations to compare two methods-matching and regression adjustment-to account for preexisting differences between intervention and comparison groups. A broad range of potential baseline variables explained relatively little of the variation in child and family outcomes. This suggests the potential for bias even after accounting for these variables, highlighting the need for systematic reviews to provide appropriate cautions about interpreting the results of moderately rated, nonexperimental studies. Our simulations showed that regression adjustment can yield unbiased estimates if all relevant covariates are used, even when the model is misspecified, and preexisting differences between the intervention and the comparison groups exist.

Assessing the Accuracy of Generalized Inferences From Comparison Group Studies Using a Within-Study Comparison Approach: The Methodology.

PubMed

Jaciw, Andrew P

2016-06-01

Various studies have examined bias in impact estimates from comparison group studies (CGSs) of job training programs, and in education, where results are benchmarked against experimental results. Such within-study comparison (WSC) approaches investigate levels of bias in CGS-based impact estimates, as well as the success of various design and analytic strategies for reducing bias. This article reviews past literature and summarizes conditions under which CGSs replicate experimental benchmark results. It extends the framework to, and develops the methodology for, situations where results from CGSs are generalized to untreated inference populations. Past research is summarized; methods are developed to examine bias in program impact estimates based on cross-site comparisons in a multisite trial that are evaluated against site-specific experimental benchmarks. Students in Grades K-3 in 79 schools in Tennessee; students in Grades 4-8 in 82 schools in Alabama. Grades K-3 Stanford Achievement Test (SAT) in reading and math scores; Grades 4-8 SAT10 reading scores. Past studies show that bias in CGS-based estimates can be limited through strong design, with local matching, and appropriate analysis involving pretest covariates and variables that represent selection processes. Extension of the methodology to investigate accuracy of generalized estimates from CGSs shows bias from confounders and effect moderators. CGS results, when extrapolated to untreated inference populations, may be biased due to variation in outcomes and impact. Accounting for effects of confounders or moderators may reduce bias. © The Author(s) 2016.

An ROI Comparison of Initiatives Designed to Attract Diverse Students to Technology Careers

ERIC Educational Resources Information Center

Dillon, Thomas W.; Reif, Harry L.; Thomas, Daphyne S.

2016-01-01

This study examines two alternative interventions designed to attract diverse students to pursue information technology or, more generally, STEM (science, technology, engineering, and math) careers from a Return on Investment (ROI) perspective. More specifically, this study examines the effectiveness and efficiency of single-day and multi-day…

77 FR 17065 - Proposed Data Collections Submitted for Public Comment and Recommendations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-23

... comparison communities will enable use of a quasi-experimental, baseline and follow-up study design for... are no studies that have examined the impact of smoke free policies by comparing pre- and post SHS... Patient Protection and Affordable Care Act, which is designed to expand and sustain the necessary...

A study of an orbital radar mapping mission to Venus. Volume 3: Parametric studies and subsystem comparisons

NASA Technical Reports Server (NTRS)

1973-01-01

Parametric studies and subsystem comparisons for the orbital radar mapping mission to planet Venus are presented. Launch vehicle requirements and primary orbiter propulsion system requirements are evaluated. The systems parametric analysis indicated that orbit size and orientation interrelated with almost all of the principal spacecraft systems and influenced significantly the definition of orbit insertion propulsion requirements, weight in orbit capability, radar system design, and mapping strategy.

Digital Games, Design, and Learning: A Systematic Review and Meta-Analysis

ERIC Educational Resources Information Center

Clark, Douglas B.; Tanner-Smith, Emily E.; Killingsworth, Stephen S.

2016-01-01

In this meta-analysis, we systematically reviewed research on digital games and learning for K-16 students. We synthesized comparisons of game versus nongame conditions (i.e., media comparisons) and comparisons of augmented games versus standard game designs (i.e., value-added comparisons). We used random-effects meta-regression models with robust…

Advanced Neutron Spectrometer

NASA Technical Reports Server (NTRS)

Christl, Mark; Dobson, Chris; Norwood, Joseph; Kayatin, Matthew; Apple, Jeff; Gibson, Brian; Dietz, Kurt; Benson, Carl; Smith, Dennis; Howard, David;

A study of an orbital radar mapping mission to Venus. Volume 2: Configuration comparisons and systems evaluation

NASA Technical Reports Server (NTRS)

1973-01-01

Configuration comparisons and systems evaluation for the orbital radar mapping mission of the planet Venus are discussed. Designs are recommended which best satisfy the science objectives of the Venus radar mapping concept. Attention is given to the interaction and integration of those specific mission-systems recommendations with one another, and the final proposed designs are presented. The feasibility, cost, and scheduling of these configurations are evaluated against assumptions of reasonable state-of-the-art growth and space funding expectations.

Topology Optimization using the Level Set and eXtended Finite Element Methods: Theory and Applications

NASA Astrophysics Data System (ADS)

Villanueva Perez, Carlos Hernan

Computational design optimization provides designers with automated techniques to develop novel and non-intuitive optimal designs. Topology optimization is a design optimization technique that allows for the evolution of a broad variety of geometries in the optimization process. Traditional density-based topology optimization methods often lack a sufficient resolution of the geometry and physical response, which prevents direct use of the optimized design in manufacturing and the accurate modeling of the physical response of boundary conditions. The goal of this thesis is to introduce a unified topology optimization framework that uses the Level Set Method (LSM) to describe the design geometry and the eXtended Finite Element Method (XFEM) to solve the governing equations and measure the performance of the design. The methodology is presented as an alternative to density-based optimization approaches, and is able to accommodate a broad range of engineering design problems. The framework presents state-of-the-art methods for immersed boundary techniques to stabilize the systems of equations and enforce the boundary conditions, and is studied with applications in 2D and 3D linear elastic structures, incompressible flow, and energy and species transport problems to test the robustness and the characteristics of the method. A comparison of the framework against density-based topology optimization approaches is studied with regards to convergence, performance, and the capability to manufacture the designs. Furthermore, the ability to control the shape of the design to operate within manufacturing constraints is developed and studied. The analysis capability of the framework is validated quantitatively through comparison against previous benchmark studies, and qualitatively through its application to topology optimization problems. The design optimization problems converge to intuitive designs and resembled well the results from previous 2D or density-based studies.

A Comparison of Japanese and American Housewives' Attitudes toward Employment of Women.

ERIC Educational Resources Information Center

Engel, John W.

This study describes the attitudes of Japanese housewives toward women's employment, and compares them with those of American housewives. A questionnaire was designed to assess beliefs and attitudes related to women's roles in work and family life. It was translated into Japanese for purposes of comparison. Questionnaires were administered to over…

Comparison of Aero-Propulsive Performance Predictions for Distributed Propulsion Configurations

NASA Technical Reports Server (NTRS)

Borer, Nicholas K.; Derlaga, Joseph M.; Deere, Karen A.; Carter, Melissa B.; Viken, Sally A.; Patterson, Michael D.; Litherland, Brandon L.; Stoll, Alex M.

2017-01-01

NASA's X-57 "Maxwell" flight demonstrator incorporates distributed electric propulsion technologies in a design that will achieve a significant reduction in energy used in cruise flight. A substantial portion of these energy savings come from beneficial aerodynamic-propulsion interaction. Previous research has shown the benefits of particular instantiations of distributed propulsion, such as the use of wingtip-mounted cruise propellers and leading edge high-lift propellers. However, these benefits have not been reduced to a generalized design or analysis approach suitable for large-scale design exploration. This paper discusses the rapid, "design-order" toolchains developed to investigate the large, complex tradespace of candidate geometries for the X-57. Due to the lack of an appropriate, rigorous set of validation data, the results of these tools were compared to three different computational flow solvers for selected wing and propulsion geometries. The comparisons were conducted using a common input geometry, but otherwise different input grids and, when appropriate, different flow assumptions to bound the comparisons. The results of these studies showed that the X-57 distributed propulsion wing should be able to meet the as-designed performance in cruise flight, while also meeting or exceeding targets for high-lift generation in low-speed flight.

Comparison of female foot morphology and last design in athletic footwear--are men's lasts appropriate for women?

PubMed

Krauss, Inga; Valiant, Gordon; Horstmann, Thomas; Grau, Stefan

2010-04-01

The purpose of this study was to investigate differences between female feet and last design. Four hundred twenty-four feet and four men's running shoe lasts (U.S. women 6.0-9.5), which also are used for the manufacturing of women's shoes, were scanned in three dimensions. Six foot measures were quantified. Different foot types were classified using a cluster analysis. Comparisons were made between last measures and averaged as well as foot type specific foot measures. Differences in width measures between lasts and foot types vary substantially (0-9 mm). Length grading is similar for lasts and feet (differences < 1mm). Width grading is larger in lasts in comparison with average grading in feet (3.5-5.9 mm). Last design and grading should account for the sex-specific allometry in foot measures. The use of down-graded men's lasts for women's shoes has to be questioned. Therefore, sex-specific reference measures and wear tests should incorporate different foot types in different sizes to allow suitable implications for a proper design and grading of lasts.

Optimizing adaptive design for Phase 2 dose-finding trials incorporating long-term success and financial considerations: A case study for neuropathic pain.

PubMed

Gao, Jingjing; Nangia, Narinder; Jia, Jia; Bolognese, James; Bhattacharyya, Jaydeep; Patel, Nitin

2017-06-01

In this paper, we propose an adaptive randomization design for Phase 2 dose-finding trials to optimize Net Present Value (NPV) for an experimental drug. We replace the traditional fixed sample size design (Patel, et al., 2012) by this new design to see if NPV from the original paper can be improved. Comparison of the proposed design to the previous design is made via simulations using a hypothetical example based on a Diabetic Neuropathic Pain Study. Copyright © 2017 Elsevier Inc. All rights reserved.

Sampling Designs in Qualitative Research: Making the Sampling Process More Public

ERIC Educational Resources Information Center

Onwuegbuzie, Anthony J.; Leech, Nancy L.

2007-01-01

The purpose of this paper is to provide a typology of sampling designs for qualitative researchers. We introduce the following sampling strategies: (a) parallel sampling designs, which represent a body of sampling strategies that facilitate credible comparisons of two or more different subgroups that are extracted from the same levels of study;…

Causal Inference and the Comparative Interrupted Time Series Design: Findings from Within-Study Comparisons

ERIC Educational Resources Information Center

St. Clair, Travis; Hallberg, Kelly; Cook, Thomas D.

2014-01-01

Researchers are increasingly using comparative interrupted time series (CITS) designs to estimate the effects of programs and policies when randomized controlled trials are not feasible. In a simple interrupted time series design, researchers compare the pre-treatment values of a treatment group time series to post-treatment values in order to…

A Comparison of Parallelism in Interface Designs for Computer-Based Learning Environments

ERIC Educational Resources Information Center

Min, Rik; Yu, Tao; Spenkelink, Gerd; Vos, Hans

2004-01-01

In this paper we discuss an experiment that was carried out with a prototype, designed in conformity with the concept of parallelism and the Parallel Instruction theory (the PI theory). We designed this prototype with five different interfaces, and ran an empirical study in which 18 participants completed an abstract task. The five basic designs…

Strengthening the Regression Discontinuity Design Using Additional Design Elements: A Within-Study Comparison

ERIC Educational Resources Information Center

Wing, Coady; Cook, Thomas D.

2013-01-01

The sharp regression discontinuity design (RDD) has three key weaknesses compared to the randomized clinical trial (RCT). It has lower statistical power, it is more dependent on statistical modeling assumptions, and its treatment effect estimates are limited to the narrow subpopulation of cases immediately around the cutoff, which is rarely of…

An International Comparison of Final-Year Design Project Curricula

ERIC Educational Resources Information Center

Kentish, Sandra E.; Shallcross, David C.

2006-01-01

This paper reviews design teaching at a total of 15 chemical engineering departments across Australia, Singapore, and the United Kingdom. The emphasis is on the capstone Design Project, which can be viewed as a major transition subject for students as they move into the workplace. The study shows that this subject has evolved to act as an…

Satellite time and frequency transfer (STIFT)

NASA Technical Reports Server (NTRS)

Vessot, R. F. C.

1983-01-01

The concept of placing a hydrogen maser high stability clock in Earth orbit to provide accurate time and frequency comparisons worldwide to major timing centers and to a large number of radio observatory antenna sites involved in VLBI measurements was studied. The proposal was chiefly directed toward studies and initial hardware designs for time comparisons between hydrogen maser frequency standards and to modifications of the hydrogen maser for long-term use in space.

Recreation safety in municipal parks - Bloomington, Indiana and Tsukuba, Japan: a comparison study of risk management

Treesearch

Bruce Hronek

2001-01-01

Cultural differences affects the design and use of playground equipment in parks. Comparative research exploring the differences in playground facilities, parental supervision, and use was conducted on-site in Tsukuba City, Ibaraki Perfecture, Japan and Bloomington, Indiana, USA. The study examines park design, play equipment, sports fields, use patterns, and parental...

An Investigation of the Effects of Relevant Samples and a Comparison of Verification versus Discovery Based Lab Design

ERIC Educational Resources Information Center

Rieben, James C., Jr.

2010-01-01

This study focuses on the effects of relevance and lab design on student learning within the chemistry laboratory environment. A general chemistry conductivity of solutions experiment and an upper level organic chemistry cellulose regeneration experiment were employed. In the conductivity experiment, the two main variables studied were the effect…

Classroom versus Computer-Based CPR Training: A Comparison of the Effectiveness of Two Instructional Methods

ERIC Educational Resources Information Center

Rehberg, Robb S.; Gazzillo Diaz, Linda; Middlemas, David A.

2009-01-01

Objective: The objective of this study was to determine whether computer-based CPR training is comparable to traditional classroom training. Design and Setting: This study was quantitative in design. Data was gathered from a standardized examination and skill performance evaluation which yielded numerical scores. Subjects: The subjects were 64…

The Effectiveness of Teaching Methods Used in Graphic Design Pedagogy in Both Analogue and Digital Education Systems

ERIC Educational Resources Information Center

Alhajri, Salman

2016-01-01

Purpose: this paper investigates the effectiveness of teaching methods used in graphic design pedagogy in both analogue and digital education systems. Methodology and approach: the paper is based on theoretical study using a qualitative, case study approach. Comparison between the digital teaching methods and traditional teaching methods was…

Advanced general aviation comparative engine/airframe integration study

NASA Technical Reports Server (NTRS)

Huggins, G. L.; Ellis, D. R.

1981-01-01

The NASA Advanced Aviation Comparative Engine/Airframe Integration Study was initiated to help determine which of four promising concepts for new general aviation engines for the 1990's should be considered for further research funding. The engine concepts included rotary, diesel, spark ignition, and turboprop powerplants; a conventional state-of-the-art piston engine was used as a baseline for the comparison. Computer simulations of the performance of single and twin engine pressurized aircraft designs were used to determine how the various characteristics of each engine interacted in the design process. Comparisons were made of how each engine performed relative to the others when integrated into an airframe and required to fly a transportation mission.

Invited review: study design considerations for clinical research in veterinary radiology and radiation oncology.

PubMed

Scrivani, Peter V; Erb, Hollis N

2013-01-01

High quality clinical research is essential for advancing knowledge in the areas of veterinary radiology and radiation oncology. Types of clinical research studies may include experimental studies, method-comparison studies, and patient-based studies. Experimental studies explore issues relative to pathophysiology, patient safety, and treatment efficacy. Method-comparison studies evaluate agreement between techniques or between observers. Patient-based studies investigate naturally acquired disease and focus on questions asked in clinical practice that relate to individuals or populations (e.g., risk, accuracy, or prognosis). Careful preplanning and study design are essential in order to achieve valid results. A key point to planning studies is ensuring that the design is tailored to the study objectives. Good design includes a comprehensive literature review, asking suitable questions, selecting the proper sample population, collecting the appropriate data, performing the correct statistical analyses, and drawing conclusions supported by the available evidence. Most study designs are classified by whether they are experimental or observational, longitudinal or cross-sectional, and prospective or retrospective. Additional features (e.g., controlled, randomized, or blinded) may be described that address bias. Two related challenging aspects of study design are defining an important research question and selecting an appropriate sample population. The sample population should represent the target population as much as possible. Furthermore, when comparing groups, it is important that the groups are as alike to each other as possible except for the variables of interest. Medical images are well suited for clinical research because imaging signs are categorical or numerical variables that might be predictors or outcomes of diseases or treatments. © 2013 Veterinary Radiology & Ultrasound.

Comparing State-Space Multivariable Controls to Multi-SISO Controls for Load Reduction of Drivetrain-Coupled Modes on Wind Turbines through Field-Testing: Preprint

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

Fleming, P. A.; van Wingerden, J. W.; Wright, A. D.

2011-12-01

This paper presents the structure of an ongoing controller comparison experiment at NREL's National Wind Technology Center; the design process for the two controllers compared in this phase of the experiment, and initial comparison results obtained in field-testing. The intention of the study is to demonstrate the advantage of using modern multivariable methods for designing control systems for wind turbines versus conventional approaches. We will demonstrate the advantages through field-test results from experimental turbines located at the NWTC. At least two controllers are being developed side-by-side to meet an incrementally increasing number of turbine load-reduction objectives. The first, a multiplemore » single-input, single-output (m-SISO) approach, uses separately developed decoupled and classicially tuned controllers, which is, to the best of our knowledge, common practice in the wind industry. The remaining controllers are developed using state-space multiple-input and multiple-output (MIMO) techniques to explicity account for coupling between loops and to optimize given known frequency structures of the turbine and disturbance. In this first publication from the study, we present the structure of the ongoing controller comparison experiment, the design process for the two controllers compared in this phase, and initial comparison results obtained in field-testing.« less

Comparison of Instructors' and Students' Perceptions of the Effectiveness of Online Courses

ERIC Educational Resources Information Center

Seok, Soonhwa; DaCosta, Boaventura; Kinsell, Carolyn; Tung, Chan K.

2010-01-01

This study used an extensive online course evaluation inventory to analyze the subjects' perceptions of course effectiveness in the following subscales: flexibility, user interface, navigation, getting started, technical assistance, course management, universal design, communications, instructional design, and content. Survey results compared…

Performance of Subsurface Tube Drainage System in Saline Soils: A Case Study

NASA Astrophysics Data System (ADS)

Pali, A. K.

2015-06-01

In order to improve the saline and water logged soils caused due to groundwater table rise, installation of subsurface drainage system is considered as one of the best remedies. However, the design of the drainage system has to be accurate so that the field performance results conform to the designed results. In this investigation, the field performance of subsurface tube drainage system installed at the study area was evaluated. The performance was evaluated on the basis of comparison of the designed value of water table drop as 30 cm after 2 days of drainage and predicted and field measured hydraulic heads for a consecutive drainage period of 14 days. The investigation revealed that the actual drop of water table after 2 days of drainage was 25 cm, about 17 % less than the designed value of 30 cm after 2 days of drainage. The comparison of hydraulic heads predicted by Van Schilfgaarde equation of unsteady drainage with the field-measured hydraulic heads showed that the deviation of predicted hydraulic heads varied within a range of ±8 % indicating high acceptability of Van Schlifgaarde equation for designing subsurface drainage system in saline and water logged soils resembling to that of the study area.

Simulation technology for resuscitation training: a systematic review and meta-analysis.

PubMed

Mundell, William C; Kennedy, Cassie C; Szostek, Jason H; Cook, David A

2013-09-01

To summarize current available data on simulation-based training in resuscitation for health care professionals. MEDLINE, EMBASE, CINAHL, PsycINFO, ERIC, Web of Science, Scopus and reference lists of published reviews. Published studies of any language or date that enrolled health professions' learners to investigate the use of technology-enhanced simulation to teach resuscitation in comparison with no intervention or alternative training. Data were abstracted in duplicate. We identified themes examining different approaches to curriculum design. We pooled results using random effects meta-analysis. 182 studies were identified involving 16,636 participants. Overall, simulation-based training of resuscitation skills, in comparison to no intervention, appears effective regardless of assessed outcome, level of learner, study design, or specific task trained. In comparison to no intervention, simulation training improved outcomes of knowledge (Hedges' g) 1.05 (95% confidence interval, 0.81-1.29), process skill 1.13 (0.99-1.27), product skill 1.92 (1.26-2.60), time skill 1.77 (1.13-2.42) and patient outcomes 0.26 (0.047-0.48). In comparison with non-simulation intervention, learner satisfaction 0.79 (0.27-1.31) and process skill 0.35 (0.12-0.59) outcomes favored simulation. Studies investigating how to optimize simulation training found higher process skill outcomes in courses employing "booster" practice 0.13 (0.03-0.22), team/group dynamics 0.51 (0.06-0.97), distraction 1.76 (1.02-2.50) and integrated feedback 0.49 (0.17-0.80) compared to courses without these features. Most analyses reflected high between-study inconsistency (I(2) values >50%). Simulation-based training for resuscitation is highly effective. Design features of "booster" practice, team/group dynamics, distraction and integrated feedback improve effectiveness. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Quasi-experimental evaluation without regression analysis.

PubMed

Rohrer, James E

2009-01-01

Evaluators of public health programs in field settings cannot always randomize subjects into experimental or control groups. By default, they may choose to employ the weakest study design available: the pretest, posttest approach without a comparison group. This essay argues that natural experiments involving comparison groups are within reach of public health program managers. Methods for analyzing natural experiments are discussed.

Pairwise Multiple Comparisons in Single Group Repeated Measures Analysis.

ERIC Educational Resources Information Center

Barcikowski, Robert S.; Elliott, Ronald S.

Research was conducted to provide educational researchers with a choice of pairwise multiple comparison procedures (P-MCPs) to use with single group repeated measures designs. The following were studied through two Monte Carlo (MC) simulations: (1) The T procedure of J. W. Tukey (1953); (2) a modification of Tukey's T (G. Keppel, 1973); (3) the…

Using Graphic Organizers to Teach Content Area Material to Students with Learning Disabilities

ERIC Educational Resources Information Center

Dexter, Douglas D.

2012-01-01

A pretest-posttest comparison group design was used to investigate the effects of a semantic mapping lesson plus visual display versus a semantic mapping lesson alone on adolescents' with learning disabilities (LD) ability to gain and maintain factual knowledge from expository social studies material. In addition, a posttest only comparison group…

Multi-dimensional free-electron laser simulation codes : a comparison study.

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

Biedron, S. G.; Chae, Y. C.; Dejus, R. J.

A self-amplified spontaneous emission (SASE) free-electron laser (FEL) is under construction at the Advanced Photon Source (APS). Five FEL simulation codes were used in the design phase: GENESIS, GINGER, MEDUSA, RON, and TDA3D. Initial comparisons between each of these independent formulations show good agreement for the parameters of the APS SASE FEL.

Multi-Dimensional Free-Electron Laser Simulation Codes: A Comparison Study

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

Nuhn, Heinz-Dieter

A self-amplified spontaneous emission (SASE) free-electron laser (FEL) is under construction at the Advanced Photon Source (APS). Five FEL simulation codes were used in the design phase: GENESIS, GINGER, MEDUSA, RON, and TDA3D. Initial comparisons between each of these independent formulations show good agreement for the parameters of the APS SASE FEL.

Lunar surface transportation systems conceptual design lunar base systems study Task 5.2

NASA Technical Reports Server (NTRS)

1988-01-01

Conceptual designs for three categories of lunar surface transportation were described. The level of understanding for the capabilities and design approach varies between the vehicles representing these categories. A summary of the vehicle categories and current state of conceptual design is provided. Finally, a brief evaluation and discussion is provided for a systematic comparison of transportation categories and effectiveness in supporting transportation objectives.

Digital Games, Design, and Learning: A Systematic Review and Meta-Analysis.

PubMed

Clark, Douglas B; Tanner-Smith, Emily E; Killingsworth, Stephen S

2016-03-01

In this meta-analysis, we systematically reviewed research on digital games and learning for K-16 students. We synthesized comparisons of game versus nongame conditions (i.e., media comparisons) and comparisons of augmented games versus standard game designs (i.e., value-added comparisons). We used random-effects meta-regression models with robust variance estimates to summarize overall effects and explore potential moderator effects. Results from media comparisons indicated that digital games significantly enhanced student learning relative to nongame conditions ([Formula: see text] = 0.33, 95% confidence interval [0.19, 0.48], k = 57, n = 209). Results from value-added comparisons indicated significant learning benefits associated with augmented game designs ([Formula: see text] = 0.34, 95% confidence interval [0.17, 0.51], k = 20, n = 40). Moderator analyses demonstrated that effects varied across various game mechanics characteristics, visual and narrative characteristics, and research quality characteristics. Taken together, the results highlight the affordances of games for learning as well as the key role of design beyond medium.

Digital Games, Design, and Learning

PubMed Central

Clark, Douglas B.; Tanner-Smith, Emily E.; Killingsworth, Stephen S.

2016-01-01

In this meta-analysis, we systematically reviewed research on digital games and learning for K–16 students. We synthesized comparisons of game versus nongame conditions (i.e., media comparisons) and comparisons of augmented games versus standard game designs (i.e., value-added comparisons). We used random-effects meta-regression models with robust variance estimates to summarize overall effects and explore potential moderator effects. Results from media comparisons indicated that digital games significantly enhanced student learning relative to nongame conditions (g¯ = 0.33, 95% confidence interval [0.19, 0.48], k = 57, n = 209). Results from value-added comparisons indicated significant learning benefits associated with augmented game designs (g¯ = 0.34, 95% confidence interval [0.17, 0.51], k = 20, n = 40). Moderator analyses demonstrated that effects varied across various game mechanics characteristics, visual and narrative characteristics, and research quality characteristics. Taken together, the results highlight the affordances of games for learning as well as the key role of design beyond medium. PMID:26937054

Nurse Middle-Managers: The Relationship of Managerial Motivation to Academic Education, Leadership Training, and Success Potential

DTIC Science & Technology

1992-05-12

compared to an untested one. The quasi-experinmtal design with nonequivalent comparison groups included leadership training between pre and posttests...experimental, pretest-posttest, nonequivalent comparison groups (Wave A & Wave B) design . It allowed investigation of the influence of leadership training on...provided comparison groups . According to Burns and Grove (1987), pretest-posttest designs have inherent threats to validity. Pretest administration

Fluid design studies of integrated modular engine system

NASA Technical Reports Server (NTRS)

Frankenfield, Bruce; Carek, Jerry

1993-01-01

A study was performed to develop a fluid system design and show the feasibility of constructing an integrated modular engine (IME) configuration, using an expander cycle engine. The primary design goal of the IME configuration was to improve the propulsion system reliability. The IME fluid system was designed as a single fault tolerant system, while minimizing the required fluid components. This study addresses the design of the high pressure manifolds, turbopumps and thrust chambers for the IME configuration. A physical layout drawing was made, which located each of the fluid system components, manifolds and thrust chambers. Finally, a comparison was made between the fluid system designs of an IME system and a non-network (clustered) engine system.

A COMPARISON OF ANALYSIS UNITS FOR ASSOCIATING LYME DISEASE WITH FOREST-EDGE HABITAT

EPA Science Inventory

This study assessed the relationship between land-cover pattern and Lyme disease incidence rate when modeled under three designs for data aggregation. Incidence rates were calculated from passive surveillance data reported in 12 Maryland counties during 1996 – 2000. A design usin...

Reference Standards, Judges, and Comparison Subjects

PubMed Central

Hripcsak, George; Wilcox, Adam

2002-01-01

Medical informatics systems are often designed to perform at the level of human experts. Evaluation of the performance of these systems is often constrained by lack of reference standards, either because the appropriate response is not known or because no simple appropriate response exists. Even when performance can be assessed, it is not always clear whether the performance is sufficient or reasonable. These challenges can be addressed if an evaluator enlists the help of clinical domain experts. 1) The experts can carry out the same tasks as the system, and then their responses can be combined to generate a reference standard. 2)The experts can judge the appropriateness of system output directly. 3) The experts can serve as comparison subjects with which the system can be compared. These are separate roles that have different implications for study design, metrics, and issues of reliability and validity. Diagrams help delineate the roles of experts in complex study designs. PMID:11751799

Comparison of sampling designs for estimating deforestation from landsat TM and MODIS imagery: a case study in Mato Grosso, Brazil.

PubMed

Zhu, Shanyou; Zhang, Hailong; Liu, Ronggao; Cao, Yun; Zhang, Guixin

2014-01-01

Sampling designs are commonly used to estimate deforestation over large areas, but comparisons between different sampling strategies are required. Using PRODES deforestation data as a reference, deforestation in the state of Mato Grosso in Brazil from 2005 to 2006 is evaluated using Landsat imagery and a nearly synchronous MODIS dataset. The MODIS-derived deforestation is used to assist in sampling and extrapolation. Three sampling designs are compared according to the estimated deforestation of the entire study area based on simple extrapolation and linear regression models. The results show that stratified sampling for strata construction and sample allocation using the MODIS-derived deforestation hotspots provided more precise estimations than simple random and systematic sampling. Moreover, the relationship between the MODIS-derived and TM-derived deforestation provides a precise estimate of the total deforestation area as well as the distribution of deforestation in each block.

Comparison of Sampling Designs for Estimating Deforestation from Landsat TM and MODIS Imagery: A Case Study in Mato Grosso, Brazil

PubMed Central

Zhu, Shanyou; Zhang, Hailong; Liu, Ronggao; Cao, Yun; Zhang, Guixin

2014-01-01

Sampling designs are commonly used to estimate deforestation over large areas, but comparisons between different sampling strategies are required. Using PRODES deforestation data as a reference, deforestation in the state of Mato Grosso in Brazil from 2005 to 2006 is evaluated using Landsat imagery and a nearly synchronous MODIS dataset. The MODIS-derived deforestation is used to assist in sampling and extrapolation. Three sampling designs are compared according to the estimated deforestation of the entire study area based on simple extrapolation and linear regression models. The results show that stratified sampling for strata construction and sample allocation using the MODIS-derived deforestation hotspots provided more precise estimations than simple random and systematic sampling. Moreover, the relationship between the MODIS-derived and TM-derived deforestation provides a precise estimate of the total deforestation area as well as the distribution of deforestation in each block. PMID:25258742

Comparing two methods of education (virtual versus traditional) on learning of Iranian dental students: a post-test only design study.

PubMed

Moazami, Fariborz; Bahrampour, Ehsan; Azar, Mohammad Reza; Jahedi, Farzad; Moattari, Marzieh

2014-03-05

The importance of using technologies such as e-learning in different disciplines is discussed in the literature. Researchers have measured the effectiveness of e-learning in a number of fields.Considering the lack of research on the effectiveness of online learning in dental education particularly in Iran, the advantages of these learning methods and the positive university atmosphere regarding the use of online learning. This study, therefore, aims to compare the effects of two methods of teaching (virtual versus traditional) on student learning. This post-test only design study approached 40, fifth year dental students of Shiraz University of Medical Sciences. From this group, 35 students agreed to participate. These students were randomly allocated into two groups, experimental (virtual learning) and comparison (traditional learning). To ensure similarity between groups, we compared GPAs of all participants by the Mann-Whitney U test (P > 0.05). The experimental group received a virtual learning environment courseware package specifically designed for this study, whereas the control group received the same module structured in a traditional lecture form. The virtual learning environment consisted of online and offline materials. Two identical valid, reliable post-tests that consisted of 40 multiple choice questions (MCQs) and 4 essay questions were administered immediately (15 min) after the last session and two months later to assess for knowledge retention. Data were analyzed by SPSS version 20. A comparison of the mean knowledge score of both groups showed that virtual learning was more effective than traditional learning (effect size = 0.69). The newly designed virtual learning package is feasible and will result in more effective learning in comparison with lecture-based training. However further studies are needed to generalize the findings of this study.

An Empirical Comparison of Five Linear Equating Methods for the NEAT Design

ERIC Educational Resources Information Center

Suh, Youngsuk; Mroch, Andrew A.; Kane, Michael T.; Ripkey, Douglas R.

2009-01-01

In this study, a data base containing the responses of 40,000 candidates to 90 multiple-choice questions was used to mimic data sets for 50-item tests under the "nonequivalent groups with anchor test" (NEAT) design. Using these smaller data sets, we evaluated the performance of five linear equating methods for the NEAT design with five levels of…

An Ex-Post Facto Examination of Relationships among the Developmental Designs Professional Development Model/Classroom Management Approach, School Leadership, Climate, Student Achievement, Attendance, and Behavior in High Poverty, Middle Grades Schools

ERIC Educational Resources Information Center

Hough, David L.; Schmitt, Vicki L.

2011-01-01

This study reports finding from an ex post facto causal-comparison study utilizing data from a multifaceted program evaluation of a professional development approach to classroom management known as Development Designs 1 and Developmental Designs 2 (DD1 & D2). Data from this program evaluation indicate that teachers implement a number of classroom…

A novel maximum power point tracking system employing phase comparison techniques

NASA Astrophysics Data System (ADS)

Avaritsiotis, J. N.; Tsitomeneas, S.; Caroubalos, C.

A new MPPT design is presented that is based on the comparison of the phase of a perturbing signal with that of the signal which is the result of the perturbation. More specifically, a voltage ripple is induced on the power loop of the P/V system and its phase is compared to the phase of the resulting ripple on the electric power P = I x V, where I and V are the current and voltage respectively of the P/V generator. A prototype MPPT based on the previous principle has been designed, constructed, and its performance has been studied.

Design of a control configured tanker aircraft

NASA Technical Reports Server (NTRS)

Walker, S. A.

1976-01-01

The benefits that accrue from using control configured vehicle (CCV) concepts were examined along with the techniques for applying these concepts to an advanced tanker aircraft design. Reduced static stability (RSS) and flutter mode control (FMC) were the two primary CCV concepts used in the design. The CCV tanker was designed to the same mission requirements specified for a conventional tanker design. A seven degree of freedom mathematical model of the flexible aircraft was derived and used to synthesize a lateral stability augmentation system (SAS), a longitudinal control augmentation system (CAS), and a FMC system. Fatigue life and cost analyses followed the control system synthesis, after which a comparative evaluation of the CCV and conventional tankers was made. This comparison indicated that the CCV weight and cost were lower but that, for this design iteration, the CCV fatigue life was shorter. Also, the CCV crew station acceleration was lower, but the acceleration at the boom operator station was higher relative to the corresponding conventional tanker. Comparison of the design processes used in the CCV and conventional design studies revealed that they were basically the same.

Child Sexual Abuse in America--A Call for School & Community Action. A Report of a National Study.

ERIC Educational Resources Information Center

Helge, Doris

The rate of sexual abuse of children and adults in our society is appalling, and growing rapidly. This study was designed to determine trends in child sexual abuse prevention and treatment services offered by school districts across America. The questionnaire was designed to allow comparisons of urban, rural, and suburban school district programs…

Fall-Related Hospitalization and Facility Costs among Residents of Institutions Providing Long-Term Care

ERIC Educational Resources Information Center

Carroll, Norman V.; Delafuente, Jeffrey C.; Cox, Fred M.; Narayanan, Siva

2008-01-01

Purpose: The purpose of this study was to estimate hospital and long-term-care costs resulting from falls in long-term-care facilities (LTCFs). Design and Methods: The study used a retrospective, pre/post with comparison group design. We used matching, based on propensity scores, to control for baseline differences between fallers and non-fallers.…

A Comparison of Prose and Algorithms for Presenting Complex Instructions. Document Design Project, Technical Report No. 17.

ERIC Educational Resources Information Center

Holland, V. Melissa; Rose, Andrew

Complex conditional instructions ("if X, then do Y") are prevalent in public documents, where they typically appear in prose form. Results of two previous studies have shown that conditional instructions become very difficult to process as the structure becomes more complex. A study was designed to investigate whether this difficulty can…

Influenza vaccine effectiveness by test-negative design - Comparison of inpatient and outpatient settings.

PubMed

Feng, Shuo; Cowling, Benjamin J; Sullivan, Sheena G

2016-03-29

Observational studies of influenza vaccine effectiveness (VE) are increasingly using the test-negative design. Studies are typically based in outpatient or inpatient settings, but these two approaches are rarely compared directly. The aim of our study was to assess whether influenza VE estimates differ between inpatient and outpatient settings. We searched the literature from Medline, PubMed and Web of Science using a combination of keywords to identify published studies of influenza VE using the test-negative design. Studies assessing any type of influenza vaccine among any population in any setting were considered, while interim studies or re-analyses were excluded. Retrieved articles were reviewed, screened and categorized based on study setting, location and influenza season. We searched for parallel studies in inpatient and outpatient settings that were done in the same influenza season, in the same location, and in the same or similar age groups. For each of the pairs identified, we estimated the difference in VE estimates between settings, and we tested whether the average difference was significant using a paired t-test. In total 25 pairs of estimates were identified that permitted comparisons between VE estimates in inpatient and outpatient study settings. Within pairs, the prevalence of influenza was generally higher among patients enrolled in the outpatient studies, while influenza vaccination coverage among the test-negative control groups was generally higher in the inpatient studies. There was no heterogeneity in the paired differences in VE, and the pooled difference in VE between inpatient and outpatient studies was -2% (95% confidence interval: -12%, 10%). We found no differences in VE estimates between inpatient and outpatient settings by studies using the test-negative design. Further research involving direct comparisons of VE estimates from the two settings in the same populations and years would be valuable. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Comparison of the Results of Many-Facet Rasch Analyses Based on Crossed and Judge Pair Designs

ERIC Educational Resources Information Center

Ilhan, Mustafa

2016-01-01

The aim of this study was to compare the results of many-facet Rasch analyses based on crossed and judge pair designs. The study was conducted with 168 eighth grade students and five judges. The study data were collected using an achievement test with open-ended questions and a holistic rubric that was used to rate the responses. In the data…

Experiencing and Regulating Sadness: Physiological and Cognitive Effects

ERIC Educational Resources Information Center

Robinson, Jennifer L.; Demaree, Heath A.

2009-01-01

No prior study has examined the two most prominent response-focused regulation strategies (suppression and exaggeration) using a within-subjects design. Utilizing this design allows for a direct comparison of physiological patterns and cognitive impairment associated with such efforts. One hundred and nine participants were asked to view a series…

Performance Outcomes of an Online First Aid and CPR Course for Laypersons

ERIC Educational Resources Information Center

Cason, Carolyn L.; Stiller, Janeth

2011-01-01

Objective: The study evaluated the effectiveness of an online first aid course by comparing it with the traditional instructor-led course. An effective online course increases course accessibility and mitigates the major deterrent to widespread layperson training. Design: A comparison group design evaluated performances among 25 laypersons…

A Comparison of Active Student Responding Modalities in a General Psychology Course

ERIC Educational Resources Information Center

Zayac, Ryan M.; Ratkos, Thom; Frieder, Jessica E.; Paulk, Amber

2016-01-01

Research on teaching has shown that incorporating active student responding (ASR) into classroom instruction facilitates learning and should be considered best practice. Nevertheless, few published studies have examined ASR using a within-participant design across a semester. Using a counterbalanced alternating treatment design, a direct…

Nontraditional Intersections/Interchanges: Informational Report

DOT National Transportation Integrated Search

2007-06-18

Comprehensive Coverage -Geometric design considerations. -Traffic analysis and comparison with similar conventional design. -Signal settings. -Signing and marking. -Material or cost comparison. -Selection Process in a spread sheet.

Evaluation of Plume Divergence and Facility Effects on Far-Field Faraday Probe Current Density Profiles

DTIC Science & Technology

2009-09-01

elevated background pressure, compared nude Faraday probe designs, and evaluated design modifications to minimize uncertainty due to charge exchange...evaluated Faraday probe design and facility background pressure on collected ion current. A comparison of two nude Faraday probe designs concluded...140.5 Plasma potential in the region surrounding a nude Faraday probe has been measured to study the possibility of probe bias voltage acting as a

Assessment and comparison of 100-MW coal gasification phosphoric acid fuel cell power plants

NASA Technical Reports Server (NTRS)

Lu, Cheng-Yi

1988-01-01

One of the advantages of fuel cell (FC) power plants is fuel versatility. With changes only in the fuel processor, the power plant will be able to accept a variety of fuels. This study was performed to design process diagrams, evaluate performance, and to estimate cost of 100 MW coal gasifier (CG)/phosphoric acid fuel cell (PAFC) power plant systems utilizing coal, which is the largest single potential source of alternate hydrocarbon liquids and gases in the United States, as the fuel. Results of this study will identify the most promising integrated CG/PAFC design and its near-optimal operating conditions. The comparison is based on the performance and cost of electricity which is calculated under consistent financial assumptions.

A Computational/Experimental Study of Two Optimized Supersonic Transport Designs and the Reference H Baseline

NASA Technical Reports Server (NTRS)

Cliff, Susan E.; Baker, Timothy J.; Hicks, Raymond M.; Reuther, James J.

1999-01-01

Two supersonic transport configurations designed by use of non-linear aerodynamic optimization methods are compared with a linearly designed baseline configuration. One optimized configuration, designated Ames 7-04, was designed at NASA Ames Research Center using an Euler flow solver, and the other, designated Boeing W27, was designed at Boeing using a full-potential method. The two optimized configurations and the baseline were tested in the NASA Langley Unitary Plan Supersonic Wind Tunnel to evaluate the non-linear design optimization methodologies. In addition, the experimental results are compared with computational predictions for each of the three configurations from the Enter flow solver, AIRPLANE. The computational and experimental results both indicate moderate to substantial performance gains for the optimized configurations over the baseline configuration. The computed performance changes with and without diverters and nacelles were in excellent agreement with experiment for all three models. Comparisons of the computational and experimental cruise drag increments for the optimized configurations relative to the baseline show excellent agreement for the model designed by the Euler method, but poorer comparisons were found for the configuration designed by the full-potential code.

The Development and Validation of Test Instruments to Measure Observation and Comparison in Junior High School Science.

ERIC Educational Resources Information Center

Hungerford, Harold Ralph

This study attempted to design tests for the purpose of measuring the acquisition of the science skills of observation and comparison, to determine if these skills, as measured by these tests, could be differentially improved using differing amounts of training, and to determine the effects of race and cultural status on performance with the…

The Effects of Handwriting Instruction on Reading for Students in Grades 1 and 2

ERIC Educational Resources Information Center

Stroik, Linda R.

2016-01-01

The purpose of this quantitative quasi-experimental group comparison study using a repeated measures comparison group design with random assignment of subjects to groups was to investigate the effects of handwriting instruction on reading progress for learners in grade 1 and grade 2. At three points in time, the number of words each student read…

Cross-Cultural Comparisons of Child-Reported Emotional and Physical Abuse: Rates, Risk Factors and Psychosocial Symptoms

ERIC Educational Resources Information Center

Sebre, Sandra; Sprugevica, Ieva; Novotni, Antoni; Bonevski, Dimitar; Pakalniskiene, Vilmante; Popescu, Daniela; Turchina, Tatiana; Friedrich, William; Lewis, Owen

2004-01-01

Objectives: This study was designed to assess the incidence of child emotional and physical abuse, associated risk factors and psychosocial symptoms in a cross-cultural comparison between post-communist bloc countries. Method: One-thousand one-hundred forty-five children ages 10-14 from Latvia (N=297), Lithuania (N=300), Macedonia (N=302), and…

Comparison of high performance liquid chromatography and enzymatic analysis of soluble carbohydrates in loblolly pine

Treesearch

Patricia L. Faulkner; Michele M. Schoeneberger; Kim H. Ludovici

1993-01-01

Foliar tissue was collected from a field study designed to test impacts of atmospheric pollutants on loblolIy pine (Pinus taeda L.) seedlings. Standard enzymatic (ENZ) and high performance liquid chromatography (HPLC) methods were used to analyze the tissue for soluble sugars. A comparison of the methods revealed no significant diffennces in accuracy...

Effects of Comparison and Game-Challenge on Sixth Graders' Algebra Variable Learning Achievement, Learning Attitude, and Meta-Cognitive Awareness

ERIC Educational Resources Information Center

Sun Lin, Hong-Zheng; Chiou, Guey-Fa

2017-01-01

This study examined the effects of comparison and game-challenge strategies on sixth graders' learning achievement of algebra variable, learning attitude towards algebra variable learning, and meta-cognitive awareness of algebra variable learning. A 2 × 2 factorial design was used, and 86 students were invited to participate in the experimental…

Qualitative Research as a Method for Making Just Comparisons of Pedagogic Quality in Higher Education: A Pilot Study

ERIC Educational Resources Information Center

Abbas, Andrea; McLean, Monica

2007-01-01

Systems designed to ensure that teaching and student learning are of a suitable quality are a feature of universities globally. Quality assurance systems are central to attempts to internationalise higher education, motivated in part by a concern for greater global equality. Yet, if such systems incorporate comparisons, the tendency is to reflect…

Performance assessment of solid state actuators through a common procedure and comparison criteria

NASA Astrophysics Data System (ADS)

Reithler, Livier; Guedra-Degeorges, Didier

1998-07-01

The design of systems based on smart structure technologies for active shape and vibration control and high precision positioning requires a good knowledge of the behavior of the active materials (electrostrictive and piezoelectric ceramics and polymers, magnetostrictive and shape memory alloys...) and of commercially available actuators. Extensive theoretical studies have been made on the behavior of active materials during the past decades but there are only a few developments on experimental comparisons between different kinds of commercially available actuators. The purpose of this study is to find out the pertinent parameters for the design of such systems, to set up a common static test procedure for all types of actuators and to define comparison criteria in terms of output force and displacement, mechanical and electrical energy, mass and dimensions. After having define the pertinent parameters of the characterization and having described the resulting testing procedure, test results are presented for different types of actuators based on piezoceramics and magnetostrictive alloys. The performances of each actuator are compared through both the test results and the announced characteristics: to perform this comparison absolute and relative criteria are chosen considering aeronautical and space applications.

Final report of the regional key comparison EURAMET.M.G-K1: European Comparison of Absolute Gravimeters ECAG-2011

NASA Astrophysics Data System (ADS)

Francis, Olivier; Klein, Gilbert; Baumann, Henri; Dando, Nicolas; Tracey, Ray; Ullrich, Christian; Castelein, Stefaan; Hua, Hu; Kang, Wu; Chongyang, Shen; Songbo, Xuan; Hongbo, Tan; Zhengyuan, Li; Pálinkás, Vojtech; Kostelecký, Jakub; Mäkinen, Jaakko; Näränen, Jyri; Merlet, Sébastien; Farah, Tristan; Guerlin, Christine; Pereira Dos Santos, Franck; Le Moigne, Nicolas; Champollion, Cédric; Deville, Sabrina; Timmen, Ludger; Falk, Reinhard; Wilmes, Herbert; Iacovone, Domenico; Baccaro, Francesco; Germak, Alessandro; Biolcati, Emanuele; Krynski, Jan; Sekowski, Marcin; Olszak, Tomasz; Pachuta, Andrzej; Agren, Jonas; Engfeldt, Andreas; Reudink, René; Inacio, Pedro; McLaughlin, Daniel; Shannon, Geoff; Eckl, Marc; Wilkins, Tim; van Westrum, Derek; Billson, Ryan

2012-01-01

During November 2011 a EURAMET key comparison of absolute gravimeters was organized in the Underground Laboratory for Geodynamics in Walferdange, Luxemburg. The comparison assembled 22 participants coming from 16 countries and four different continents. The comparison was divided into two parts: a key comparison that included six National Metrology Institutes or Designated Institutes, and a pilot study including all participants. The global result given by the pilot study confirms that all instruments are absolutely coherent with each other. The results obtained in the key comparison confirm a good agreement between the NMI instruments. Finally, a link to ICAG-2009 shows also that the NMI gravimeters are stable in time. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Comparison study on flexible pavement design using FAA (Federal Aviation Administration) and LCN (Load Classification Number) code in Ahmad Yani international airport’s runway

NASA Astrophysics Data System (ADS)

Santoso, S. E.; Sulistiono, D.; Mawardi, A. F.

2017-11-01

FAA code for airport design has been broadly used by Indonesian Ministry of Aviation since decades ago. However, there is not much comprehensive study about its relevance and efficiency towards current situation in Indonesia. Therefore, a further comparison study on flexible pavement design for airport runway using comparable method has become essential. The main focus of this study is to compare which method between FAA and LCN that offer the most efficient and effective way in runway pavement planning. The comparative methods in this study mainly use the variety of variable approach. FAA code for instance, will use the approach on the aircraft’s maximum take-off weight and annual departure. Whilst LCN code use the variable of equivalent single wheel load and tire pressure. Based on the variables mentioned above, a further classification and rated method will be used to determine which code is best implemented. According to the analysis, it is clear that FAA method is the most effective way to plan runway design in Indonesia with consecutively total pavement thickness of 127cm and LCN method total pavement thickness of 70cm. Although, FAA total pavement is thicker that LCN its relevance towards sustainable and pristine condition in the future has become an essential aspect to consider in design and planning.

Comparative Packaging Study

NASA Technical Reports Server (NTRS)

Perchonok, Michele; Antonini, David

2008-01-01

This viewgraph presentation describes a comparative packaging study for use on long duration space missions. The topics include: 1) Purpose; 2) Deliverables; 3) Food Sample Selection; 4) Experimental Design Matrix; 5) Permeation Rate Comparison; and 6) Packaging Material Information.

Economics of PPP-insulated pipe-type cable: Final report

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

Ernst, A.

1987-10-01

This study has been designed to establish the economic range of application and the potential cost advantage of PPP-insulated pipe-type cable compared with presently utilized paper-insulated designs. The study is in two parts. In the first part the electrical and thermal characteristics of a range of cable sizes are tabulated. This data can be utilized for planning and economic comparison purposes. In the second part 12 transmission load scenarios are studied to determine the relative cost of various designs considering materials, installation and the losses over a wide range of assumptions.

A Multiple-Sequence Variant of the Multiple-Baseline Design: A Strategy for Analysis of Sequence Effects and Treatment Comparison.

ERIC Educational Resources Information Center

Noell, George H.; Gresham, Frank M.

2001-01-01

Describes design logic and potential uses of a variant of the multiple-baseline design. The multiple-baseline multiple-sequence (MBL-MS) consists of multiple-baseline designs that are interlaced with one another and include all possible sequences of treatments. The MBL-MS design appears to be primarily useful for comparison of treatments taking…

The Bobath (NDT) concept in adult neurological rehabilitation: what is the state of the knowledge? A scoping review. Part II: intervention studies perspectives.

PubMed

Vaughan-Graham, Julie; Cott, Cheryl; Wright, F Virginia

2015-01-01

The study's purpose was to describe the range of knowledge pertaining to the Bobath (NDT) concept in adult neurological rehabilitation, synthesizes the findings, identify knowledge gaps and develop empirically based recommendations for future research. A scoping review of research and non-research articles published from 2007 to 2012. Two independent reviewers selected studies based on a systematic procedure. Inclusion criteria for studies were electronically accessible English language literature with Bobath and/or Neurodevelopmental Therapy as the subject heading in the title/keyword/abstract/intervention comparison with respect to adult neurological conditions. Data were abstracted and summarized with respect to study design, theoretical framework, clinical application including population representation, study fidelity, intervention comparison, duration of care, measurement and findings. Of the 33 publications identified 17 were intervention studies (11 RCT's/1 prospective parallel group design/5 N-of-1). One other paper was a systematic review. The intervention studies, primarily RCT designs, have serious methodological concerns particularly related to study/treatment fidelity and measurement resulting in no clear clinical direction. Aspects such as theoretical framework, therapist skill, quality of movement measurement and individualized interventions require careful consideration in the design of Bobath studies. Implications for Rehabilitation Future intervention studies should be based on the current Bobath theoretical framework and key aspects of clinical practice. Study and treatment fidelity issues need to be carefully considered when interpreting the results of existing RCT's evaluating the Bobath concept. N-of-1 randomized, observational, factorial and mixed method study designs should be considered as alternative study options.

The Comparison Of Dome And HMD Delivery Systems: A Case Study

NASA Technical Reports Server (NTRS)

Chen, Jian; Harm, Deborah L.; Loftin, R. Bowen; Tyalor, Laura C.; Leiss, Ernst L.

2002-01-01

For effective astronaut training applications, choosing the right display devices to present images is crucial. In order to assess what devices are appropriate, it is important to design a successful virtual environment for a comparison study of the display devices. We present a comprehensive system, a Virtual environment testbed (VET), for the comparison of Dome and Head Mounted Display (HMD) systems on an SGI Onyx workstation. By writing codelets, we allow a variety of virtual scenarios and subjects' information to be loaded without programming or changing the code. This is part of an ongoing research project conducted by the NASA / JSC.

Aerodynamic Limits on Large Civil Tiltrotor Sizing and Efficiency

NASA Technical Reports Server (NTRS)

Acree, C W., Jr.

2014-01-01

The NASA Large Civil Tiltrotor (2nd generation, or LCTR2) has been the reference design for avariety of NASA studies of design optimization, engine and gearbox technology, handling qualities, andother areas, with contributions from NASA Ames, Glenn and Langley Centers, plus academic and industrystudies. Ongoing work includes airfoil design, 3D blade optimization, engine technology studies, andwingrotor aerodynamic interference. The proposed paper will bring the design up to date with the latestresults of such studies, then explore the limits of what aerodynamic improvements might hope toaccomplish. The purpose is two-fold: 1) determine where future technology studies might have the greatestpayoff, and 2) establish a stronger basis of comparison for studies of other vehicle configurations andmissions.

Students as Game Designers vs. "Just" Players: Comparison of Two Different Approaches to Location-Based Games Implementation into School Curricula

ERIC Educational Resources Information Center

Slussareff, Michaela; Bohácková, Petra

2016-01-01

This paper compares two kinds of educational treatment within location-based game approach; learning by playing a location-based game and learning by designing a location-based game. Two parallel elementary school classes were included in our study (N = 27; age 14-15). The "designers" class took part in the whole process of game design…

Factor levels for density comparisons in the split-block spacing design

Treesearch

Kurt H. Riitters; Brian J. Stanton; Robbert H. Walkup

1989-01-01

The split-block spacing design is a compact test of the effects of within-row and between-row spacings. But the sometimes awkward analysis of density (i.e., trees/ha) effects may deter use of the design. The analysis is simpler if the row spacings are chosen to obtain a balanced set of equally spaced density and rectangularity treatments. A spacing study in poplar (...

Satellite Power Systems (SPS) concept definition study, exhibit C. Volume 6: In-depth element investigation

NASA Technical Reports Server (NTRS)

Hanley, G.

1979-01-01

Computer assisted design of a gallium arsenide solid state dc-to-RF converter with supportive fabrication data was investigated. Specific tasks performed include: computer program checkout; amplifier comparisons; computer design analysis of GaSa solar cells; and GaAs diode evaluation. Results obtained in the design and evaluation of transistors for the microwave space power system are presented.

A phase II flexible screening design allowing for interim analysis and comparison with historical control.

PubMed

Wu, Wenting; Bot, Brian; Hu, Yan; Geyer, Susan M; Sargent, Daniel J

2013-07-01

Sargent and Goldberg [1] proposed a randomized phase II flexible screening design (SG design) which took multiple characteristics of candidate regimens into consideration in selecting a regimen for further phase III testing. In this paper, we extend the SG design by including provisions for an interim analysis and/or a comparison to a historical control. By including a comparison with a historical control, a modified SG design not only identifies a more promising treatment but also assures that the regimen has a clinically meaningful level of efficacy as compared to a historical control. By including an interim analysis, a modified SG design could reduce the number of patients exposed to inferior treatment regimens. When compared to the original SG design, the modified designs increase the sample size moderately, but expand the utility of the flexible screening design substantially. Copyright © 2013 Elsevier Inc. All rights reserved.

Set size influences the relationship between ANS acuity and math performance: a result of different strategies?

PubMed

Dietrich, Julia Felicitas; Nuerk, Hans-Christoph; Klein, Elise; Moeller, Korbinian; Huber, Stefan

2017-08-29

Previous research has proposed that the approximate number system (ANS) constitutes a building block for later mathematical abilities. Therefore, numerous studies investigated the relationship between ANS acuity and mathematical performance, but results are inconsistent. Properties of the experimental design have been discussed as a potential explanation of these inconsistencies. In the present study, we investigated the influence of set size and presentation duration on the association between non-symbolic magnitude comparison and math performance. Moreover, we focused on strategies reported as an explanation for these inconsistencies. In particular, we employed a non-symbolic magnitude comparison task and asked participants how they solved the task. We observed that set size was a significant moderator of the relationship between non-symbolic magnitude comparison and math performance, whereas presentation duration of the stimuli did not moderate this relationship. This supports the notion that specific design characteristics contribute to the inconsistent results. Moreover, participants reported different strategies including numerosity-based, visual, counting, calculation-based, and subitizing strategies. Frequencies of these strategies differed between different set sizes and presentation durations. However, we found no specific strategy, which alone predicted arithmetic performance, but when considering the frequency of all reported strategies, arithmetic performance could be predicted. Visual strategies made the largest contribution to this prediction. To conclude, the present findings suggest that different design characteristics contribute to the inconsistent findings regarding the relationship between non-symbolic magnitude comparison and mathematical performance by inducing different strategies and additional processes.

An evaluation of 1D loss model collections for the off-design performance prediction of automotive turbocharger compressors

NASA Astrophysics Data System (ADS)

Harley, P.; Spence, S.; Early, J.; Filsinger, D.; Dietrich, M.

2013-12-01

Single-zone modelling is used to assess different collections of impeller 1D loss models. Three collections of loss models have been identified in literature, and the background to each of these collections is discussed. Each collection is evaluated using three modern automotive turbocharger style centrifugal compressors; comparisons of performance for each of the collections are made. An empirical data set taken from standard hot gas stand tests for each turbocharger is used as a baseline for comparison. Compressor range is predicted in this study; impeller diffusion ratio is shown to be a useful method of predicting compressor surge in 1D, and choke is predicted using basic compressible flow theory. The compressor designer can use this as a guide to identify the most compatible collection of losses for turbocharger compressor design applications. The analysis indicates the most appropriate collection for the design of automotive turbocharger centrifugal compressors.

A Quasi-Experimental Study on Using Short Stories: Statistical and Inferential Analyses on the Non-English Major University Students' Speaking and Writing Achievements

ERIC Educational Resources Information Center

Iman, Jaya Nur

2017-01-01

This research was conducted to find out whether or not using short stories significantly improve the speaking and writing achievements. A quasi-experimental study of non-equivalent pretest-posttest control group design or comparison group design was used in this research. The population of this research was the all first semester undergraduate…

Effects of Human Factors in Engineering and Design for Teaching Mathematics: A Comparison Study of Online and Face-to-Face at a Technical College

ERIC Educational Resources Information Center

Mativo, John M.; Hill, Roger B.; Godfrey, Paul W.

2013-01-01

The focus of this study was to examine four characteristics for successful and unsuccessful students enrolled in basic mathematics courses at a technical college. The characteristics, considered to be in part effects of human factors in engineering and design, examined the preferred learning styles, computer information systems competency,…

The Effects of Swedish Knife Model on Students' Understanding of the Digestive System

ERIC Educational Resources Information Center

Cerrah Ozsevgec, Lale; Artun, Huseyin; Unal, Melike

2012-01-01

This study was designed to examine the effect of Swedish Knife Model on students' understanding of digestive system. A simple experimental design (pretest-treatment-posttest) was used in the study and internal comparison of the results of the one group was made. The sample consisted of 40 7th grade Turkish students whose ages range from 13 to 15.…

Exoplanet Yield Estimation for Decadal Study Concepts using EXOSIMS

NASA Astrophysics Data System (ADS)

Morgan, Rhonda; Lowrance, Patrick; Savransky, Dmitry; Garrett, Daniel

2016-01-01

The anticipated upcoming large mission study concepts for the direct imaging of exo-earths present an exciting opportunity for exoplanet discovery and characterization. While these telescope concepts would also be capable of conducting a broad range of astrophysical investigations, the most difficult technology challenges are driven by the requirements for imaging exo-earths. The exoplanet science yield for these mission concepts will drive design trades and mission concept comparisons.To assist in these trade studies, the Exoplanet Exploration Program Office (ExEP) is developing a yield estimation tool that emphasizes transparency and consistent comparison of various design concepts. The tool will provide a parametric estimate of science yield of various mission concepts using contrast curves from physics-based model codes and Monte Carlo simulations of design reference missions using realistic constraints, such as solar avoidance angles, the observatory orbit, propulsion limitations of star shades, the accessibility of candidate targets, local and background zodiacal light levels, and background confusion by stars and galaxies. The python tool utilizes Dmitry Savransky's EXOSIMS (Exoplanet Open-Source Imaging Mission Simulator) design reference mission simulator that is being developed for the WFIRST Preliminary Science program. ExEP is extending and validating the tool for future mission concepts under consideration for the upcoming 2020 decadal review. We present a validation plan and preliminary yield results for a point design.

A comparison of control strategies for wave energy converters

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

Coe, Ryan G.; Bacelli, Giorgio; Wilson, David G.

In this study, we employ a numerical model to compare the performance of a number of wave energy converter control strategies. The controllers selected for evaluation span a wide range in their requirements for implementation. Each control strategy is evaluated using a single numerical model with a set of sea states to represent a deployment site off the coast of Newport, OR. A number of metrics, ranging from power absorption to kinematics, are employed to provide a comparison of each control strategy’s performance that accounts for both relative benefits and costs. The results show a wide range of performances frommore » the different controllers and highlight the need for a holistic design approach which considers control design as a parallel component within the larger process WEC design.« less

A comparison of control strategies for wave energy converters

DOE PAGES

Coe, Ryan G.; Bacelli, Giorgio; Wilson, David G.; ...

2017-11-15

In this study, we employ a numerical model to compare the performance of a number of wave energy converter control strategies. The controllers selected for evaluation span a wide range in their requirements for implementation. Each control strategy is evaluated using a single numerical model with a set of sea states to represent a deployment site off the coast of Newport, OR. A number of metrics, ranging from power absorption to kinematics, are employed to provide a comparison of each control strategy’s performance that accounts for both relative benefits and costs. The results show a wide range of performances frommore » the different controllers and highlight the need for a holistic design approach which considers control design as a parallel component within the larger process WEC design.« less

Cost-efficient designs for three-arm trials with treatment delivered by health professionals: Sample sizes for a combination of nested and crossed designs

PubMed Central

Moerbeek, Mirjam

2018-01-01

Background This article studies the design of trials that compare three treatment conditions that are delivered by two types of health professionals. The one type of health professional delivers one treatment, and the other type delivers two treatments, hence, this design is a combination of a nested and crossed design. As each health professional treats multiple patients, the data have a nested structure. This nested structure has thus far been ignored in the design of such trials, which may result in an underestimate of the required sample size. In the design stage, the sample sizes should be determined such that a desired power is achieved for each of the three pairwise comparisons, while keeping costs or sample size at a minimum. Methods The statistical model that relates outcome to treatment condition and explicitly takes the nested data structure into account is presented. Mathematical expressions that relate sample size to power are derived for each of the three pairwise comparisons on the basis of this model. The cost-efficient design achieves sufficient power for each pairwise comparison at lowest costs. Alternatively, one may minimize the total number of patients. The sample sizes are found numerically and an Internet application is available for this purpose. The design is also compared to a nested design in which each health professional delivers just one treatment. Results Mathematical expressions show that this design is more efficient than the nested design. For each pairwise comparison, power increases with the number of health professionals and the number of patients per health professional. The methodology of finding a cost-efficient design is illustrated using a trial that compares treatments for social phobia. The optimal sample sizes reflect the costs for training and supervising psychologists and psychiatrists, and the patient-level costs in the three treatment conditions. Conclusion This article provides the methodology for designing trials that compare three treatment conditions while taking the nesting of patients within health professionals into account. As such, it helps to avoid underpowered trials. To use the methodology, a priori estimates of the total outcome variances and intraclass correlation coefficients must be obtained from experts’ opinions or findings in the literature. PMID:29316807

Context Matters: Volunteer Bias, Small Sample Size, and the Value of Comparison Groups in the Assessment of Research-Based Undergraduate Introductory Biology Lab Courses

PubMed Central

Brownell, Sara E.; Kloser, Matthew J.; Fukami, Tadashi; Shavelson, Richard J.

2013-01-01

The shift from cookbook to authentic research-based lab courses in undergraduate biology necessitates the need for evaluation and assessment of these novel courses. Although the biology education community has made progress in this area, it is important that we interpret the effectiveness of these courses with caution and remain mindful of inherent limitations to our study designs that may impact internal and external validity. The specific context of a research study can have a dramatic impact on the conclusions. We present a case study of our own three-year investigation of the impact of a research-based introductory lab course, highlighting how volunteer students, a lack of a comparison group, and small sample sizes can be limitations of a study design that can affect the interpretation of the effectiveness of a course. PMID:24358380

Context matters: volunteer bias, small sample size, and the value of comparison groups in the assessment of research-based undergraduate introductory biology lab courses.

PubMed

Brownell, Sara E; Kloser, Matthew J; Fukami, Tadashi; Shavelson, Richard J

2013-01-01

The shift from cookbook to authentic research-based lab courses in undergraduate biology necessitates the need for evaluation and assessment of these novel courses. Although the biology education community has made progress in this area, it is important that we interpret the effectiveness of these courses with caution and remain mindful of inherent limitations to our study designs that may impact internal and external validity. The specific context of a research study can have a dramatic impact on the conclusions. We present a case study of our own three-year investigation of the impact of a research-based introductory lab course, highlighting how volunteer students, a lack of a comparison group, and small sample sizes can be limitations of a study design that can affect the interpretation of the effectiveness of a course.

When Control Groups Do Not Exist: Program Evaluation without a Net.

ERIC Educational Resources Information Center

Clark, Sheldon B.; And Others

Suggestions, based on the experience of researchers at Oak Ridge (Tennessee) Associated Universities (ORAU), are offered on how evaluations in which true experimental designs are not possible can be designed for meaningful comparison. The ORAU conducts evaluation and assessment studies of educational programs intended to explore some aspect of the…

Design Matters: Explorations of Content and Design in Fraction Games

ERIC Educational Resources Information Center

Gresalfi, Melissa Sommerfeld; Rittle-Johnson, Bethany; Loehr, Abbey; Nichols, Isaac

2018-01-01

The goal of the current study was to contribute to our emergent understanding of whether and how particular types of digital games can support student learning and engagement. We focused on commercially available educational apps that focused on similar content (fraction comparison and equivalence) but represented extremes in how game-like they…

Towards a Taxonomy of Intergenerational Knowledge Transfer Practices: Insights from an International Comparison (Germany-Quebec)

ERIC Educational Resources Information Center

Kuyken, Kerstin; Ebrahimi, Mehran; Saives, Anne-Laure

2018-01-01

Purpose: This paper aims to develop a better understanding of intergenerational knowledge transfer (IKT) practices by adopting a context-related and comparative perspective. Design/methodology/approach: A qualitative case study design involving 83 interviews and non-participative observation in German and Quebec organizations has been chosen.…

An optimized implementation of a fault-tolerant clock synchronization circuit

NASA Technical Reports Server (NTRS)

Torres-Pomales, Wilfredo

1995-01-01

A fault-tolerant clock synchronization circuit was designed and tested. A comparison to a previous design and the procedure followed to achieve the current optimization are included. The report also includes a description of the system and the results of tests performed to study the synchronization and fault-tolerant characteristics of the implementation.

Evaluation of a School-Based Multicomponent Nutrition Education Program to Improve Young Children's Fruit and Vegetable Consumption

ERIC Educational Resources Information Center

Prelip, Michael; Kinsler, Janni; Thai, Chan Le; Erausquin, Jennifer Toller; Slusser, Wendelin

2012-01-01

Objective: To assess the impact of a multicomponent nutrition education program on student knowledge, attitudes, and behaviors related to consumption of fruits and vegetables (FVs). Design: Quasi-experimental pretest/posttest research design; 3 study conditions (Intervention+, Intervention, Comparison). Setting: Six schools from the Los Angeles…

A Comparison of Simultaneous Prompting and Constant Time Delay Procedures in Teaching State Capitals

ERIC Educational Resources Information Center

Head, Kenneth David; Collins, Belva C.; Schuster, John W.; Ault, Melinda Jones

2011-01-01

This investigation compared the effectiveness and efficiency of constant time delay (CTD) and simultaneous prompting (SP) procedures in teaching discrete social studies facts to 4 high school students with learning and behavior disorders using an adapted alternating treatments design nested within a multiple probe design. The results indicated…

Comparison of Performance Due to Guided Hyperlearning, Unguided Hyperlearning, and Conventional Learning in Mathematics: An Empirical Study

ERIC Educational Resources Information Center

Fathurrohman, Maman; Porter, Anne; Worthy, Annette L.

2014-01-01

In this paper, the use of guided hyperlearning, unguided hyperlearning, and conventional learning methods in mathematics are compared. The design of the research involved a quasi-experiment with a modified single-factor multiple treatment design comparing the three learning methods, guided hyperlearning, unguided hyperlearning, and conventional…

Using endemic road features to create self-explaining roads and reduce vehicle speeds.

PubMed

Charlton, Samuel G; Mackie, Hamish W; Baas, Peter H; Hay, Karen; Menezes, Miguel; Dixon, Claire

2010-11-01

This paper describes a project undertaken to establish a self-explaining roads (SER) design programme on existing streets in an urban area. The methodology focussed on developing a process to identify functional road categories and designs based on endemic road characteristics taken from functional exemplars in the study area. The study area was divided into two sections, one to receive SER treatments designed to maximise visual differences between road categories, and a matched control area to remain untreated for purposes of comparison. The SER design for local roads included increased landscaping and community islands to limit forward visibility, and removal of road markings to create a visually distinct road environment. In comparison, roads categorised as collectors received increased delineation, addition of cycle lanes, and improved amenity for pedestrians. Speed data collected 3 months after implementation showed a significant reduction in vehicle speeds on local roads and increased homogeneity of speeds on both local and collector roads. The objective speed data, combined with residents' speed choice ratings, indicated that the project was successful in creating two discriminably different road categories. 2010 Elsevier Ltd. All rights reserved.

A Comparison of Item Selection Techniques and Exposure Control Mechanisms in CATs Using the Generalized Partial Credit Model.

ERIC Educational Resources Information Center

Pastor, Dena A.; Dodd, Barbara G.; Chang, Hua-Hua

2002-01-01

Studied the impact of using five different exposure control algorithms in two sizes of item pool calibrated using the generalized partial credit model. Simulation results show that the a-stratified design, in comparison to a no-exposure control condition, could be used to reduce item exposure and overlap and increase pool use, while degrading…

Comparison of the Effects of Video Models with and without Verbal Cueing on Task Completion by Young Adults with Moderate Intellectual Disability

ERIC Educational Resources Information Center

Mechling, Linda C.; Collins, Terri S.

2012-01-01

This study compared the effects of video models with and without verbal cuing (voice over) on the completion of fine motor cooking related tasks by four young adults with moderate intellectual disability. The effects of the two modeling conditions were compared using an adapted alternating treatments design with an extended baseline, comparison,…

Booster propulsion/vehicle impact study

NASA Technical Reports Server (NTRS)

Weldon, Vincent; Dunn, Michael; Fink, Lawrence; Phillips, Dwight; Wetzel, Eric

1988-01-01

The use of hydrogen RP-1, propane, and methane as fuels for booster engines of launch vehicles is discussed. An automated procedure for integrated launch vehicle, engine sizing, and design optimization was used to define two stage and single stage concepts for minimum dry weight. The two stage vehicles were unmanned and used a flyback booster and partially reusable orbiter. The single stage designs were fully reusable, manned flyback vehicles. Comparisons of these vehicle designs, showing the effects of using different fuels, as well as sensitivity and trending data, are presented. In addition, the automated design technique utilized for the study is described.

Peer influence on students' estimates of performance: social comparison in clinical rotations.

PubMed

Raat, A N Janet; Kuks, Jan B M; van Hell, E Ally; Cohen-Schotanus, Janke

2013-02-01

During clinical rotations, students move from one clinical situation to another. Questions exist about students' strategies for coping with these transitions. These strategies may include a process of social comparison because in this context it offers the student an opportunity to estimate his or her abilities to master a novel rotation. These estimates are relevant for learning and performance because they are related to self-efficacy. We investigated whether student estimates of their own future performance are influenced by the performance level and gender of the peer with whom the student compares him- or herself. We designed an experimental study in which participating students (n = 321) were divided into groups assigned to 12 different conditions. Each condition entailed a written comparison situation in which a peer student had completed the rotation the participant was required to undertake next. Differences between conditions were determined by the performance level (worse, similar or better) and gender of the comparison peer. The overall grade achieved by the comparison peer remained the same in all conditions. We asked participants to estimate their own future performance in that novel rotation. Differences between their estimates were analysed using analysis of variance (ANOVA). Students' estimates of their future performance were highest when the comparison peer was presented as performing less well and lowest when the comparison peer was presented as performing better (p < 0.001). Estimates of male and female students in same-gender comparison conditions did not differ. In two of three opposite-gender conditions, male students' estimates were higher than those of females (p < 0.001 and p < 0.05, respectively). Social comparison influences students' estimates of their future performance in a novel rotation. The effect depends on the performance level and gender of the comparison peer. This indicates that comparisons against particular peers may strengthen or diminish a student's self-efficacy, which, in turn, may ease or hamper the student's learning during clinical rotations. The study is limited by its experimental design. Future research should focus on students' comparison behaviour in real transitions. © Blackwell Publishing Ltd 2013.

Design and operational energy studies in a new high-rise office building. Volume 5. DOE-2: comparison with measured data

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

Not Available

1984-03-01

The purpose of the DOE-2 comparison study is to compare the energy consumption for the Park Plaza building predicted by the DOE-2.1 simulation with actual energy consumption measured by the data collection system at the building. The extensive and detailed output of the data collection system provides a basis for verifying the accuracy of DOE-2.1 at a component level over short intervals of time in each of the four seasons.

Cognitive dissonance induction in everyday life: An fMRI study.

PubMed

de Vries, Jan; Byrne, Mark; Kehoe, Elizabeth

2015-01-01

This functional magnetic resonance imaging (fMRI) study explored the neural substrates of cognitive dissonance during dissonance "induction." A novel task was developed based on the results of a separate item selection study (n = 125). Items were designed to generate dissonance by prompting participants to reflect on everyday personal experiences that were inconsistent with values they had expressed support for. One experimental condition (dissonance) and three control conditions (justification, consonance, and non-self-related inconsistency) were used for comparison. Items of all four types were presented to each participant (n = 14) in a randomized design. The fMRI analysis used a whole-brain approach focusing on the moments dissonance was induced. Results showed that in comparison with the control conditions the dissonance experience led to higher levels of activation in several brain regions. Specifically dissonance was associated with increased neural activation in key brain regions including the anterior cingulate cortex (ACC), anterior insula, inferior frontal gyrus, and precuneus. This supports current perspectives that emphasize the role of anterior cingulate and insula in dissonance processing. Less extensive activation in the prefrontal cortex than in some previous studies is consistent with this study's emphasis on dissonance induction, rather than reduction. This article also contains a short review and comparison with other fMRI studies of cognitive dissonance.

Effects of a school-based sexuality education program on peer educators: the Teen PEP model.

PubMed

Jennings, J M; Howard, S; Perotte, C L

2014-04-01

This study evaluated the impact of the Teen Prevention Education Program (Teen PEP), a peer-led sexuality education program designed to prevent unintended pregnancy and sexually transmitted infections (STIs) including HIV among high school students. The study design was a quasi-experimental, nonrandomized design conducted from May 2007 to May 2008. The sample consisted of 96 intervention (i.e. Teen PEP peer educators) and 61 comparison students from five high schools in New Jersey. Baseline and 12-month follow-up surveys were conducted. Summary statistics were generated and multiple regression analyses were conducted. In the primary intent-to-treat analyses, and secondary non-intent-to-treat analyses, Teen PEP peer educators (versus comparison students) reported significantly greater opportunities to practice sexual risk reduction skills and higher intentions to talk with friends, parents, and sex partners about sex and birth control, set boundaries with sex partners, and ask a partner to be tested for STIs including HIV. In addition in the secondary analysis, Teen PEP peer educators (as compared with the comparison students) had significantly higher scores on knowledge of sexual health issues and ability to refuse risky sexual situations. School-based sexuality education programs offering comprehensive training to peer educators may improve sexual risk behavior knowledge, attitudes and behaviors among high school students.

A glucose meter evaluation co-designed with both health professional and consumer input.

PubMed

Thompson, Harmony; Chan, Huan; Logan, Florence J; Heenan, Helen F; Taylor, Lynne; Murray, Chris; Florkowski, Christopher M; Frampton, Christopher M A; Lunt, Helen

2013-11-22

Health consumer's input into assessment of medical device safety is traditionally given either as part of study outcome (trial participants) or during post marketing surveillance. Direct consumer input into the methodological design of device assessment is less common. We discuss the difference in requirements for assessment of a measuring device from the consumer and clinician perspectives, using the example of hand held glucose meters. Around 80,000 New Zealanders with diabetes recently changed their glucose meter system, to enable ongoing access to PHARMAC subsidised meters and strips. Consumers were most interested in a direct comparison of their 'old' meter system (Accu-Chek Performa) with their 'new' meter system (CareSens brand, including the CareSens N POP), rather than comparisons against a laboratory standard. This direct comparison of meter/strip systems showed that the CareSens N POP meter read around 0.6 mmol/L higher than the Performa system. Whilst this difference is unlikely to result in major errors in clinical decision making such as major insulin dosing errors, this information is nevertheless of interest to consumers who switched meters so that they could maintain access to PHARMAC subsidised meters and strips. We recommend that when practical, the consumer perspective be incorporated into study design related to medical device assessment.

Effects of a school-based sexuality education program on peer educators: the Teen PEP model

PubMed Central

Jennings, J. M.; Howard, S.; Perotte, C. L.

2014-01-01

This study evaluated the impact of the Teen Prevention Education Program (Teen PEP), a peer-led sexuality education program designed to prevent unintended pregnancy and sexually transmitted infections (STIs) including HIV among high school students. The study design was a quasi-experimental, nonrandomized design conducted from May 2007 to May 2008. The sample consisted of 96 intervention (i.e. Teen PEP peer educators) and 61 comparison students from five high schools in New Jersey. Baseline and 12-month follow-up surveys were conducted. Summary statistics were generated and multiple regression analyses were conducted. In the primary intent-to-treat analyses, and secondary non-intent-to-treat analyses, Teen PEP peer educators (versus comparison students) reported significantly greater opportunities to practice sexual risk reduction skills and higher intentions to talk with friends, parents, and sex partners about sex and birth control, set boundaries with sex partners, and ask a partner to be tested for STIs including HIV. In addition in the secondary analysis, Teen PEP peer educators (as compared with the comparison students) had significantly higher scores on knowledge of sexual health issues and ability to refuse risky sexual situations. School-based sexuality education programs offering comprehensive training to peer educators may improve sexual risk behavior knowledge, attitudes and behaviors among high school students. PMID:24488649

A new efficient mixture screening design for optimization of media.

PubMed

Rispoli, Fred; Shah, Vishal

2009-01-01

Screening ingredients for the optimization of media is an important first step to reduce the many potential ingredients down to the vital few components. In this study, we propose a new method of screening for mixture experiments called the centroid screening design. Comparison of the proposed design with Plackett-Burman, fractional factorial, simplex lattice design, and modified mixture design shows that the centroid screening design is the most efficient of all the designs in terms of the small number of experimental runs needed and for detecting high-order interaction among ingredients. (c) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009.

Body image concern among Australian adolescent girls: the role of body comparisons with models and peers.

PubMed

Carey, Renee N; Donaghue, Ngaire; Broderick, Pia

2014-01-01

This study investigated the potential mediating roles of body comparisons with peers and models in the relationship between the internalization of thinness norms and body image concern. A total of 224 Western Australian girls aged 14-15 completed questionnaires assessing their endorsement of thinness norms, body image concerns, and frequency of body comparisons with peers and with models. Both targets of body comparisons were found to significantly mediate the relationship between the endorsement of thinness norms and body image concern, with body comparison with peers a stronger mediator than comparison with models. These findings show that body comparison with peers, in particular, plays a significant role in the experience of body image concerns among adolescent girls, and should be given a higher profile in programs designed to prevent or reduce body image concern. Copyright © 2013 Elsevier Ltd. All rights reserved.

Online and Face-to-Face Anatomy Dissection Labs: A Comparison of Levels of Achievement in Learning Outcomes and Perception of Learning and Satisfaction

ERIC Educational Resources Information Center

Davidson, Jenna L.

2017-01-01

This quantitative study examined levels of achievement in learning outcomes when using a face-to-face dissection lab compared to an online dissection lab. Constructivist theory and Understanding by Design learning framework were at the core of this research study design. Data was collected from 24 health science students at a private Midwestern…

Department of Clinical Investigation Annual Research Progress Report, Fiscal Year 1993. Volume 1

DTIC Science & Technology

1993-10-01

monocytes, total periphernuclear cells, and alveolar macrophages from four study groups : patients with concurrent Mycobacterium tuberculosis (MTBI and...research design, similar to the Solomon Four Group design will be utilized to determine if the educational intervention provided has an impact on nurses...members with approved protocols: 173 Number of approved protocols held by this group : 230 Drug evaluation/comparison studies : 94 (Does not include

Inconsistency between direct and indirect comparisons of competing interventions: meta-epidemiological study

PubMed Central

Xiong, Tengbin; Parekh-Bhurke, Sheetal; Loke, Yoon K; Sutton, Alex J; Eastwood, Alison J; Holland, Richard; Chen, Yen-Fu; Glenny, Anne-Marie; Deeks, Jonathan J; Altman, Doug G

2011-01-01

Objective To investigate the agreement between direct and indirect comparisons of competing healthcare interventions. Design Meta-epidemiological study based on sample of meta-analyses of randomised controlled trials. Data sources Cochrane Database of Systematic Reviews and PubMed. Inclusion criteria Systematic reviews that provided sufficient data for both direct comparison and independent indirect comparisons of two interventions on the basis of a common comparator and in which the odds ratio could be used as the outcome statistic. Main outcome measure Inconsistency measured by the difference in the log odds ratio between the direct and indirect methods. Results The study included 112 independent trial networks (including 1552 trials with 478 775 patients in total) that allowed both direct and indirect comparison of two interventions. Indirect comparison had already been explicitly done in only 13 of the 85 Cochrane reviews included. The inconsistency between the direct and indirect comparison was statistically significant in 16 cases (14%, 95% confidence interval 9% to 22%). The statistically significant inconsistency was associated with fewer trials, subjectively assessed outcomes, and statistically significant effects of treatment in either direct or indirect comparisons. Owing to considerable inconsistency, many (14/39) of the statistically significant effects by direct comparison became non-significant when the direct and indirect estimates were combined. Conclusions Significant inconsistency between direct and indirect comparisons may be more prevalent than previously observed. Direct and indirect estimates should be combined in mixed treatment comparisons only after adequate assessment of the consistency of the evidence. PMID:21846695

Comparison of Evolutionary (Genetic) Algorithm and Adjoint Methods for Multi-Objective Viscous Airfoil Optimizations

NASA Technical Reports Server (NTRS)

Pulliam, T. H.; Nemec, M.; Holst, T.; Zingg, D. W.; Kwak, Dochan (Technical Monitor)

2002-01-01

A comparison between an Evolutionary Algorithm (EA) and an Adjoint-Gradient (AG) Method applied to a two-dimensional Navier-Stokes code for airfoil design is presented. Both approaches use a common function evaluation code, the steady-state explicit part of the code,ARC2D. The parameterization of the design space is a common B-spline approach for an airfoil surface, which together with a common griding approach, restricts the AG and EA to the same design space. Results are presented for a class of viscous transonic airfoils in which the optimization tradeoff between drag minimization as one objective and lift maximization as another, produces the multi-objective design space. Comparisons are made for efficiency, accuracy and design consistency.

Investigation of a 0.6 hub-tip radius-ratio transonic turbine designed for secondary-flow study I : design and experimental performance of standard turbine

NASA Technical Reports Server (NTRS)

Rohlik, Harold E; Wintucky, William T; Scibbe, Herbert W

1957-01-01

Detailed design information including overall performance parameters, velocity diagrams, and blade surface velocities is presented. Experimental performance includes maps based on rating as well as total-pressure ratios showing the effect of exit whirl. Also included are results of surveys at the stator exit and downstream of the rotor at design speed and specific work. This information will be used as a standard for comparison with subsequent secondary-flow work.

How Can Comparison Groups Strengthen Regression Discontinuity Designs?

ERIC Educational Resources Information Center

Wing, Coady; Cook, Thomas D.

2011-01-01

In this paper, the authors examine some of the ways that different types of non-equivalent comparison groups can be used to strengthen causal inferences based on regression discontinuity design (RDD). First, they consider a design that incorporates pre-test data on assignment scores and outcomes that were collected either before the treatment…

Reference standards, judges, and comparison subjects: roles for experts in evaluating system performance.

PubMed

Hripcsak, George; Wilcox, Adam

2002-01-01

Medical informatics systems are often designed to perform at the level of human experts. Evaluation of the performance of these systems is often constrained by lack of reference standards, either because the appropriate response is not known or because no simple appropriate response exists. Even when performance can be assessed, it is not always clear whether the performance is sufficient or reasonable. These challenges can be addressed if an evaluator enlists the help of clinical domain experts. 1) The experts can carry out the same tasks as the system, and then their responses can be combined to generate a reference standard. 2)The experts can judge the appropriateness of system output directly. 3) The experts can serve as comparison subjects with which the system can be compared. These are separate roles that have different implications for study design, metrics, and issues of reliability and validity. Diagrams help delineate the roles of experts in complex study designs.

Study of the application of hydrogen fuel to long-range subsonic transport aircraft. Volume 1: Summary

NASA Technical Reports Server (NTRS)

Brewer, G. D.; Morris, R. E.; Lange, R. H.; Moore, J. W.

1975-01-01

The feasibility of using liquid hydrogen as fuel in advanced designs of long range, subsonic transport aircraft is assessed. Both passenger and cargo type aircraft are investigated. Comparisons of physical, performance, and economic parameters of the LH2 fueled designs with conventionally fueled aircraft are presented. Design studies are conducted to determine appropriate characteristics for the hydrogen related systems required on board the aircraft. These studies included consideration of material, structural, and thermodynamic requirements of the cryogenic fuel tanks and fuel systems with the structural support and thermal protection systems.

Hybrid receiver study

NASA Technical Reports Server (NTRS)

Stone, M. S.; Mcadam, P. L.; Saunders, O. W.

1977-01-01

The results are presented of a 4 month study to design a hybrid analog/digital receiver for outer planet mission probe communication links. The scope of this study includes functional design of the receiver; comparisons between analog and digital processing; hardware tradeoffs for key components including frequency generators, A/D converters, and digital processors; development and simulation of the processing algorithms for acquisition, tracking, and demodulation; and detailed design of the receiver in order to determine its size, weight, power, reliability, and radiation hardness. In addition, an evaluation was made of the receiver's capabilities to perform accurate measurement of signal strength and frequency for radio science missions.

Numerical investigation & comparison of a tandem-bladed turbocharger centrifugal compressor stage with conventional design

NASA Astrophysics Data System (ADS)

Danish, Syed Noman; Qureshi, Shafiq Rehman; EL-Leathy, Abdelrahman; Khan, Salah Ud-Din; Umer, Usama; Ma, Chaochen

2014-12-01

Extensive numerical investigations of the performance and flow structure in an unshrouded tandem-bladed centrifugal compressor are presented in comparison to a conventional compressor. Stage characteristics are explored for various tip clearance levels, axial spacings and circumferential clockings. Conventional impeller was modified to tandem-bladed design with no modifications in backsweep angle, meridional gas passage and camber distributions in order to have a true comparison with conventional design. Performance degradation is observed for both the conventional and tandem designs with increase in tip clearance. Linear-equation models for correlating stage characteristics with tip clearance are proposed. Comparing two designs, it is clearly evident that the conventional design shows better performance at moderate flow rates. However; near choke flow, tandem design gives better results primarily because of the increase in throat area. Surge point flow rate also seems to drop for tandem compressor resulting in increased range of operation.

Dose finding with the sequential parallel comparison design.

PubMed

Wang, Jessie J; Ivanova, Anastasia

2014-01-01

The sequential parallel comparison design (SPCD) is a two-stage design recommended for trials with possibly high placebo response. A drug-placebo comparison in the first stage is followed in the second stage by placebo nonresponders being re-randomized between drug and placebo. We describe how SPCD can be used in trials where multiple doses of a drug or multiple treatments are compared with placebo and present two adaptive approaches. We detail how to analyze data in such trials and give recommendations about the allocation proportion to placebo in the two stages of SPCD.

Tactical radar technology study. Volume 1: Executive summary

NASA Astrophysics Data System (ADS)

Rosien, R.; Cardone, L.; Hammers, D.; Klein, A.; Nozawa, E.

1980-03-01

This report presents results of a study to identify new technology required to provide advanced multi-threat performance capabilities in future tactical surveillance radar designs. A baseline design with optional subsystem characteristics has been synthesized to provide both functional and operational survivability in a dynamic and hostile situation postulated for the post 1985 time frame. Comparisons have been made of available technology with that required by the new baseline design to identify new technology requirements. Recommendations are presented for critical new technology programs including estimates of technical risks, costs and required development time.

V/STOL tilt rotor aircraft study. Volume 5: Definition of stowed rotor research aircraft

NASA Technical Reports Server (NTRS)

Soule, V. A.

1973-01-01

The results of a study of folding tilt rotor (stowed rotor) aircraft are presented. The effects of design cruise speed on the gross weight of a conceptual design stowed rotor aircraft are shown and a comparison is made with a conventional (non-folding) tilt rotor aircraft. A flight research stowed rotor design is presented. The program plans, including costs and schedules, are shown for the research aircraft development and a wind tunnel plan is presented for a full scale test of the aircraft.

Mastery learning for health professionals using technology-enhanced simulation: a systematic review and meta-analysis.

PubMed

Cook, David A; Brydges, Ryan; Zendejas, Benjamin; Hamstra, Stanley J; Hatala, Rose

2013-08-01

Competency-based education requires individualization of instruction. Mastery learning, an instructional approach requiring learners to achieve a defined proficiency before proceeding to the next instructional objective, offers one approach to individualization. The authors sought to summarize the quantitative outcomes of mastery learning simulation-based medical education (SBME) in comparison with no intervention and nonmastery instruction, and to determine what features of mastery SBME make it effective. The authors searched MEDLINE, EMBASE, CINAHL, ERIC, PsycINFO, Scopus, key journals, and previous review bibliographies through May 2011. They included original research in any language evaluating mastery SBME, in comparison with any intervention or no intervention, for practicing and student physicians, nurses, and other health professionals. Working in duplicate, they abstracted information on trainees, instructional design (interactivity, feedback, repetitions, and learning time), study design, and outcomes. They identified 82 studies evaluating mastery SBME. In comparison with no intervention, mastery SBME was associated with large effects on skills (41 studies; effect size [ES] 1.29 [95% confidence interval, 1.08-1.50]) and moderate effects on patient outcomes (11 studies; ES 0.73 [95% CI, 0.36-1.10]). In comparison with nonmastery SBME instruction, mastery learning was associated with large benefit in skills (3 studies; effect size 1.17 [95% CI, 0.29-2.05]) but required more time. Pretraining and additional practice improved outcomes but, again, took longer. Studies exploring enhanced feedback and self-regulated learning in the mastery model showed mixed results. Limited evidence suggests that mastery learning SBME is superior to nonmastery instruction but takes more time.

Extending the Career of the English Primary School Headteacher: A Second Headship

ERIC Educational Resources Information Center

Fidler, Brian; Jones, Jeff; Makori, Andrew

2009-01-01

Purpose: The purpose of this article is to report findings from a national study of primary headteachers in their second headship in England. This investigated their reasons for moving schools, their choice of second school and a comparison of their experiences as heads of the two schools. Design/methodology/approach: The research design involved…

An Evaluation of a Worksite Exercise Intervention Using the Social Cognitive Theory: A Pilot Study

ERIC Educational Resources Information Center

Amaya, Megan; Petosa, R. L.

2012-01-01

Purpose: To increase exercise adherence among insufficiently active adult employees. Design: A quasi-experimental separate samples pre-test-post-test group design was used to compare treatment and comparison group. Setting: The worksite. Subjects: Employees (n = 127) who did not meet current American College of Sports Medicine (ACSM)…

PLTW and Epics-High: Curriculum Comparisons to Support Problem Solving in the Context of Engineering Design. Research in Engineering and Technology Education

ERIC Educational Resources Information Center

Kelley, Todd; Brenner, Daniel C.; Pieper, Jon T.

2010-01-01

A comparative study was conducted to compare two approaches to engineering design curriculum between different schools (inter-school) and between two curricular approaches, "Project Lead the Way" (PLTW) and "Engineering Projects in Community Service" (EPIC High) (inter-curricular). The researchers collected curriculum…

Practical Skills Training in Agricultural Education--A Comparison between Traditional and Blended Approaches

ERIC Educational Resources Information Center

Deegan, Donna; Wims, Padraig; Pettit, Tony

2016-01-01

Purpose: In this article the use of blended learning multimedia materials as an education tool was compared with the traditional approach for skills training. Design/Methodology/Approach: This study was conducted in Ireland using a pre-test, post-test experimental design. All students were instructed on how to complete two skills using either a…

Comparison of a Stimulus Equivalence Protocol and Traditional Lecture for Teaching Single-Subject Designs

ERIC Educational Resources Information Center

Lovett, Sadie; Rehfeldt, Ruth Anne; Garcia, Yors; Dunning, Johnna

2011-01-01

This study compared the effects of a computer-based stimulus equivalence protocol to a traditional lecture format in teaching single-subject experimental design concepts to undergraduate students. Participants were assigned to either an equivalence or a lecture group, and performance on a paper-and-pencil test that targeted relations among the…

Meanings for Fraction as Number-Measure by Exploring the Number Line

ERIC Educational Resources Information Center

Psycharis, Giorgos; Latsi, Maria; Kynigos, Chronis

2009-01-01

This paper reports on a case-study design experiment in the domain of fraction as number-measure. We designed and implemented a set of exploratory tasks concerning comparison and ordering of fractions as well as operations with fractions. Two groups of 12-year-old students worked collaboratively using paper and pencil as well as a specially…

A Comparison of Different Teaching Designs of "Acids and Bases" Subject

ERIC Educational Resources Information Center

Ültay, Neslihan; Çalik, Muammer

2016-01-01

Inability to link the acid-base concepts with daily life phenomena (as contexts) highlights the need for further research on the context-based acid-base chemistry. In this vein, the aim of this study is to investigate the effects of different teaching designs (REACT strategy, 5Es learning model and traditional (existing) instruction) relevant with…

Multiple Measures of Juvenile Drug Court Effectiveness: Results of a Quasi-Experimental Design

ERIC Educational Resources Information Center

Rodriguez, Nancy; Webb, Vincent J.

2004-01-01

Prior studies of juvenile drug courts have been constrained by small samples, inadequate comparison groups, or limited outcome measures. The authors report on a 3-year evaluation that examines the impact of juvenile drug court participation on recidivism and drug use. A quasi-experimental design is used to compare juveniles assigned to drug court…

A Meta-Analysis of Interventions to Reduce Loneliness

PubMed Central

Masi, Christopher M.; Chen, Hsi-Yuan; Hawkley, Louise C.; Cacioppo, John T.

2013-01-01

Social and demographic trends are placing an increasing number of adults at risk for loneliness, an established risk factor for physical and mental illness. The growing costs of loneliness have led to a number of loneliness reduction interventions. Qualitative reviews have identified four primary intervention strategies: 1) improving social skills, 2) enhancing social support, 3) increasing opportunities for social contact, and 4) addressing maladaptive social cognition. An integrative meta-analysis of loneliness reduction interventions was conducted to quantify the effects of each strategy and to examine the potential role of moderator variables. Results revealed that single group pre-post and non-randomized comparison studies yielded larger mean effect sizes relative to randomized comparison studies. Among studies that used the latter design, the most successful interventions addressed maladaptive social cognition. This is consistent with current theories regarding loneliness and its etiology. Theoretical and methodological issues associated with designing new loneliness reduction interventions are discussed. PMID:20716644

A study protocol for enriching the interprofessional collaborative competency attainment survey insights.

PubMed

Jackson, Jeffrey B

2017-11-01

The following short report outlines a proposed study designed to evaluate the Interprofessional Collaborative Competency Attainment Survey and its recommended method of administration. This exploratory study seeks to determine if there is a significant difference between two methods of administration, the recommended and validated retrospective pre-test and post-test, and a traditional pre-test and post-test. If a significant difference does exist, this data will provide a means to determine the effect size of that difference. The comparison will be done using repeated measure ANOVA and the subsequent effect size will be evaluated using Cohen's d. As the retrospective design is utilised to evaluate a change in perceived competency, comparison of data from a traditional pre-test with a retrospective pre-test may provide a means for evaluation of the participants' change in understanding of the construct, and thus a more thorough picture of the forces driving changes to scores.

Truancy Interventions: A Review of the Research Literature

ERIC Educational Resources Information Center

Sutphen, Richard D.; Ford, Janet P.; Flaherty, Chris

2010-01-01

Objectives: This article presents a systematic review of the literature on evaluative studies of truancy interventions. Method: Included studies evaluating truancy interventions appearing in peer-reviewed academic journals from 1990 to 2007. Findings: In total, 16 studies were assessed. Eight studies used group comparison designs and eight studies…

Improving Reading Comprehension and Social Studies Knowledge in Middle School

ERIC Educational Resources Information Center

Vaughn, Sharon; Swanson, Elizabeth A.; Roberts, Greg; Wanzek, Jeanne; Stillman-Spisak, Stephanie J.; Solis, Michael; Simmons, Deborah

2013-01-01

This study aimed to determine the efficacy of a content acquisition and reading comprehension treatment implemented by eighth-grade social studies teachers. Using a within-teacher design, the eighth-grade teachers' social studies classes were randomly assigned to treatment or comparison conditions. Teachers (n = 5) taught the same instructional…

Investigating measurement equivalence of visual analogue scales and Likert-type scales in Internet-based personality questionnaires.

PubMed

Kuhlmann, Tim; Dantlgraber, Michael; Reips, Ulf-Dietrich

2017-12-01

Visual analogue scales (VASs) have shown superior measurement qualities in comparison to traditional Likert-type response scales in previous studies. The present study expands the comparison of response scales to properties of Internet-based personality scales in a within-subjects design. A sample of 879 participants filled out an online questionnaire measuring Conscientiousness, Excitement Seeking, and Narcissism. The questionnaire contained all instruments in both answer scale versions in a counterbalanced design. Results show comparable reliabilities, means, and SDs for the VAS versions of the original scales, in comparison to Likert-type scales. To assess the validity of the measurements, age and gender were used as criteria, because all three constructs have shown non-zero correlations with age and gender in previous research. Both response scales showed a high overlap and the proposed relationships with age and gender. The associations were largely identical, with the exception of an increase in explained variance when predicting age from the VAS version of Excitement Seeking (B10 = 1318.95, ΔR(2) = .025). VASs showed similar properties to Likert-type response scales in most cases.

Comparison of transhumeral socket designs utilizing patient assessment and in vivo skeletal and socket motion tracking: a case study.

PubMed

Resnik, Linda; Patel, Tarpit; Cooney, Shane G; Crisco, Joseph J; Fantini, Christopher

2016-01-01

This case study compares the impact of two prosthetic socket designs, a "traditional" transhumeral (TH) socket design and a Compression Released Stabilized (CRS) socket. A CRS socket was compared to the existing socket of two persons with transhumeral amputation. Comparisons included assessments of patient comfort and satisfaction with fit, as well as dynamic kinematic assessment using a novel high-speed, high-resolution, bi-plane video radiography system (XROMM, for X-ray Reconstruction of Moving Morphology). Subjects were more satisfied with the comfort of the traditional sockets, although they had positive impressions about aspects of the fit and style of the CRS socket, and thought that it provided better control. Dynamic kinematic assessment revealed that the CRS socket provided better control of the residual limb within the socket, and had less slippage as compared to a traditional TH socket design. The TH CRS socket provided better control of the residual limb within the socket, and had less slippage. However, participants were less satisfied with the comfort and overall utility of the CRS socket, and stated that additional fitting visits/modifications to the CRS socket were needed. It is possible that satisfaction with the CRS socket may have improved with prosthetic adjustment and more acclimation time. Implications for Rehabilitation A comfortable, good fitting prosthetic socket is the key factor in determining how long (or if) an upper limb amputee can tolerate wearing a prosthesis. This case series was a comparison of two socket designs, a 'traditional' socket design and a Compression Released Stabilized (CRS) socket design in persons with transhumeral amputation. The CRS socket provided better control of the residual limb within the socket, and had less slippage. However, its tightness made it more difficult to don. Both subjects were less satisfied with the comfort and overall utility of the CRS socket. However, satisfaction might have been improved with additional fitting visits and more acclimation time.

Improving the Reporting Quality of Nonrandomized Evaluations of Behavioral and Public Health Interventions: The TREND Statement

PubMed Central

Des Jarlais, Don C.; Lyles, Cynthia; Crepaz, Nicole

2004-01-01

Developing an evidence base for making public health decisions will require using data from evaluation studies with randomized and nonrandomized designs. Assessing individual studies and using studies in quantitative research syntheses require transparent reporting of the study, with sufficient detail and clarity to readily see differences and similarities among studies in the same area. The Consolidated Standards of Reporting Trials (CONSORT) statement provides guidelines for transparent reporting of randomized clinical trials. We present the initial version of the Transparent Reporting of Evaluations with Nonrandomized Designs (TREND) statement. These guidelines emphasize the reporting of theories used and descriptions of intervention and comparison conditions, research design, and methods of adjusting for possible biases in evaluation studies that use nonrandomized designs. PMID:14998794

Comparing two methods of education (virtual versus traditional) on learning of Iranian dental students: a post-test only design study

PubMed Central

2014-01-01

Background The importance of using technologies such as e-learning in different disciplines is discussed in the literature. Researchers have measured the effectiveness of e-learning in a number of fields. Considering the lack of research on the effectiveness of online learning in dental education particularly in Iran, the advantages of these learning methods and the positive university atmosphere regarding the use of online learning. This study, therefore, aims to compare the effects of two methods of teaching (virtual versus traditional) on student learning. Methods This post-test only design study approached 40, fifth year dental students of Shiraz University of Medical Sciences. From this group, 35 students agreed to participate. These students were randomly allocated into two groups, experimental (virtual learning) and comparison (traditional learning). To ensure similarity between groups, we compared GPAs of all participants by the Mann–Whitney U test (P > 0.05). The experimental group received a virtual learning environment courseware package specifically designed for this study, whereas the control group received the same module structured in a traditional lecture form. The virtual learning environment consisted of online and offline materials. Two identical valid, reliable post-tests that consisted of 40 multiple choice questions (MCQs) and 4 essay questions were administered immediately (15 min) after the last session and two months later to assess for knowledge retention. Data were analyzed by SPSS version 20. Results A comparison of the mean knowledge score of both groups showed that virtual learning was more effective than traditional learning (effect size = 0.69). Conclusion The newly designed virtual learning package is feasible and will result in more effective learning in comparison with lecture-based training. However further studies are needed to generalize the findings of this study. PMID:24597923

Use of simulation-based learning in undergraduate nurse education: An umbrella systematic review.

PubMed

Cant, Robyn P; Cooper, Simon J

2017-02-01

To conduct a systematic review to appraise and review evidence on the impact of simulation-based education for undergraduate/pre-licensure nursing students, using existing reviews of literature. An umbrella review (review of reviews). Cumulative Index of Nursing and Allied Health Literature (CINAHLPlus), PubMed, and Google Scholar. Reviews of literature conducted between 2010 and 2015 regarding simulation-based education for pre-licensure nursing students. The Joanna Briggs Institute methodology for conduct of an umbrella review was used to inform the review process. Twenty-five systematic reviews of literature were included, of which 14 were recent (2013-2015). Most described the level of evidence of component studies as a mix of experimental and quasi-experimental designs. The reviews measured around 14 different main outcome variables, thus limiting the number of primary studies that each individual review could pool to appraise. Many reviews agreed on the key learning outcome of knowledge acquisition, although no overall quantitative effect was derived. Three of four high-quality reviews found that simulation supported psychomotor development; a fourth found too few high quality studies to make a statistical comparison. Simulation statistically improved self-efficacy in pretest-posttest studies, and in experimental designs self-efficacy was superior to that of other teaching methods; lower level research designs limiting further comparison. The reviews commonly reported strong student satisfaction with simulation education and some reported improved confidence and/or critical thinking. This umbrella review took a global view of 25 reviews of simulation research in nursing education, comprising over 700 primary studies. To discern overall outcomes across reviews, statistical comparison of quantitative results (effect size) must be the key comparator. Simulation-based education contributes to students' learning in a number of ways when integrated into pre-licensure nursing curricula. Overall, use of a constellation of instruments and a lack of high quality study designs mean that there are still some gaps in evidence of effects that need to be addressed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Permanent magnet motors

NASA Astrophysics Data System (ADS)

Richter, E.

1984-09-01

The work deals with the design and analysis study for the conceptual design of an economical high efficiency ac motor based on permanent magnets. The design and trade off studies have covered the material considerations, the design tradeoff options as well as transient and steady state performance considerations, and other options. The baseline comparison is the high efficiency induction motor. The permanent magnet (PM) motor must fit into the same frame size and surpass the induction motor on a life cost basis that includes 2.5 years of operation at a 50% duty cycle. It is shown that a motor based upon ferrite magnets does meet the objectives of the program in ratings of up to 25 hp. A 7.5 motor design is carried through the conceptual design stage.

Why do we listen to music? A uses and gratifications analysis.

PubMed

Lonsdale, Adam J; North, Adrian C

2011-02-01

Four 'uses and gratifications' studies investigated peoples' reasons for listening to music (Study 1); and whether these reasons differ significantly from those associated with other leisure activities (Study 2). In Study 3, an open-ended, qualitative research design was used to investigate why people listen to music. In Study 4, a cross-sectional design was used to investigate the possibility that people of different ages might listen to music for different reasons. Findings showed that there are a number of reasons why participants listen to music, comparison of which indicated that participants listen to music primarily to manage/regulate their moods. Comparison with other leisure activities indicated that for the most part, listening to music was rated better than other leisure activities at serving an individual's different needs. This versatility may explain why music is so important to people. Evidence was also found to suggest that the reasons for listening to music may change as people grow older. ©2010 The British Psychological Society.

The effectiveness of sexual offender treatment for juveniles as measured by recidivism: a meta-analysis.

PubMed

Reitzel, Lorraine R; Carbonell, Joyce L

2006-10-01

Published and unpublished data from nine studies on juvenile sexual offender treatment effectiveness were summarized by meta-analysis (N=2986, 2604 known male). Recidivism rates for sexual, non-sexual violent, non-sexual non-violent crimes, and unspecified non-sexual were as follows: 12.53%, 24.73%, 28.51%, and 20.40%, respectively, based on an average 59-month follow-up period. Four included studies contained a control group (n=2288) and five studies included a comparison treatment group (n=698). An average weighted effect size of 0.43 (CI=0.33-0.55) was obtained, indicating a statistically significant effect of treatment on sexual recidivism. However, individual study characteristics (e.g., handling of dropouts and non-equivalent follow-up periods between treatment groups) suggest that results should be interpreted with caution. A comparison of odds ratios by quality of study design indicated that higher quality designs yielded better effect sizes, though the difference between groups was not significant.

Can sequential parallel comparison design and two-way enriched design be useful in medical device clinical trials?

PubMed

Ivanova, Anastasia; Zhang, Zhiwei; Thompson, Laura; Yang, Ying; Kotz, Richard M; Fang, Xin

2016-01-01

Sequential parallel comparison design (SPCD) was proposed for trials with high placebo response. In the first stage of SPCD subjects are randomized between placebo and active treatment. In the second stage placebo nonresponders are re-randomized between placebo and active treatment. Data from the population of "all comers" and the subpopulations of placebo nonresponders then combined to yield a single p-value for treatment comparison. Two-way enriched design (TED) is an extension of SPCD where active treatment responders are also re-randomized between placebo and active treatment in Stage 2. This article investigates the potential uses of SPCD and TED in medical device trials.

A New Trend-Following Indicator: Using SSA to Design Trading Rules

NASA Astrophysics Data System (ADS)

Leles, Michel Carlo Rodrigues; Mozelli, Leonardo Amaral; Guimarães, Homero Nogueira

Singular Spectrum Analysis (SSA) is a non-parametric approach that can be used to decompose a time-series as trends, oscillations and noise. Trend-following strategies rely on the principle that financial markets move in trends for an extended period of time. Moving Averages (MAs) are the standard indicator to design such strategies. In this study, SSA is used as an alternative method to enhance trend resolution in comparison with the traditional MA. New trading rules using SSA as indicator are proposed. This paper shows that for the Down Jones Industrial Average (DJIA) and Shangai Securities Composite Index (SSCI) time-series the SSA trading rules provided, in general, better results in comparison to MA trading rules.

ENVIRONMENTAL COMPARISON METRICS FOR LIFE CYCLE IMPACT ASSESSMENT AND PROCESS DESIGN

EPA Science Inventory

Metrics (potentials, potency factors, equivalency factors or characterization factors) are available to support the environmental comparison of alternatives in application domains like proces design and product life-cycle assessment (LCA). These metrics typically provide relative...

Metabolomics: A Window for Understanding Long Term Physical Consequences of Distrubed Sleep and Hypothalamic Pituitary Adrenal Function in Posttraumatic Stress

DTIC Science & Technology

2017-09-01

performed on pre -collected plasma samples from a study that had a two- group cross-sectional design in which main comparisons were with medically...controls. Approach Metabolomic analysis will be performed on pre -collected plasma samples from a study that had a two- group cross-sectional design in...disturbances, and health. Metabolomic analysis will be performed on pre -collected plasma samples from a study that had a two- group cross-sectional

The Effect of a Home-Based Walking Intervention on Quality of Life, Body Composition, and Estrogen Metabolism in Postmenopausal Breast Cancer Survivors

DTIC Science & Technology

2006-09-01

Effect sizes are also shown for each randomization group (i.e., effect size from pretest to posttest ) and for the comparison of the two randomization...questions were answered. This study was designed to be a pilot study to quantify effect sizes of the effect of walking on quality of life...physical activity, body composition, and depending on inclusion criteria, estrogen metabolism. Second, this study was designed to assess the degree to

Fusion reactor blanket/shield design study

NASA Astrophysics Data System (ADS)

Smith, D. L.; Clemmer, R. G.; Harkness, S. D.; Jung, J.; Krazinski, J. L.; Mattas, R. F.; Stevens, H. C.; Youngdahl, C. K.; Trachsel, C.; Bowers, D.

1979-07-01

A joint study of Tokamak reactor first wall/blanket/shield technology was conducted to identify key technological limitations for various tritium breeding blanket design concepts, establishment of a basis for assessment and comparison of the design features of each concept, and development of optimized blanket designs. The approach used involved a review of previously proposed blanket designs, analysis of critical technological problems and design features associated with each of the blanket concepts, and a detailed evaluation of the most tractable design concepts. Tritium breeding blanket concepts were evaluated according to the proposed coolant. The effort concentrated on evaluation of lithium and water cooled blanket designs and helium and molten salt cooled designs. Generalized nuclear analysis of the tritium breeding performance, an analysis of tritium breeding requirements, and a first wall stress analysis were conducted as part of the study. The impact of coolant selection on the mechanical design of a Tokamak reactor was evaluated. Reference blanket designs utilizing the four candidate coolants are presented.

Comparison of Home Retrofit Programs in Wisconsin

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

Cunningham, Kerrie; Hannigan, Eileen

2013-03-01

To explore ways to reduce customer barriers and increase home retrofit completions, several different existing home retrofit models have been implemented in the state of Wisconsin. This study compared these programs' performance in terms of savings per home and program cost per home to assess the relative cost-effectiveness of each program design. However, given the many variations in these different programs, it is difficult to establish a fair comparison based on only a small number of metrics. Therefore, the overall purpose of the study is to document these programs' performance in a case study approach to look at general patternsmore » of these metrics and other variables within the context of each program. This information can be used by energy efficiency program administrators and implementers to inform home retrofit program design. Six different program designs offered in Wisconsin for single-family energy efficiency improvements were included in the study. For each program, the research team provided information about the programs' approach and goals, characteristics, achievements and performance. The program models were then compared with performance results-program cost and energy savings-to help understand the overall strengths and weaknesses or challenges of each model.« less

Comparison of Home Retrofit Programs in Wisconsin

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

Cunningham, K.; Hannigan, E.

2013-03-01

To explore ways to reduce customer barriers and increase home retrofit completions, several different existing home retrofit models have been implemented in the state of Wisconsin. This study compared these programs' performance in terms of savings per home and program cost per home to assess the relative cost-effectiveness of each program design. However, given the many variations in these different programs, it is difficult to establish a fair comparison based on only a small number of metrics. Therefore, the overall purpose of the study is to document these programs' performance in a case study approach to look at general patternsmore » of these metrics and other variables within the context of each program. This information can be used by energy efficiency program administrators and implementers to inform home retrofit program design. Six different program designs offered in Wisconsin for single-family energy efficiency improvements were included in the study. For each program, the research team provided information about the programs' approach and goals, characteristics, achievements and performance. The program models were then compared with performance results -- program cost and energy savings -- to help understand the overall strengths and weaknesses or challenges of each model.« less

Interpreting Signal Amplitudes in Surface Electromyography Studies in Sport and Rehabilitation Sciences

PubMed Central

Vigotsky, Andrew D.; Halperin, Israel; Lehman, Gregory J.; Trajano, Gabriel S.; Vieira, Taian M.

2018-01-01

Surface electromyography (sEMG) is a popular research tool in sport and rehabilitation sciences. Common study designs include the comparison of sEMG amplitudes collected from different muscles as participants perform various exercises and techniques under different loads. Based on such comparisons, researchers attempt to draw conclusions concerning the neuro- and electrophysiological underpinning of force production and hypothesize about possible longitudinal adaptations, such as strength and hypertrophy. However, such conclusions are frequently unsubstantiated and unwarranted. Hence, the goal of this review is to discuss what can and cannot be inferred from comparative research designs as it pertains to both the acute and longitudinal outcomes. General methodological recommendations are made, gaps in the literature are identified, and lines for future research to help improve the applicability of sEMG are suggested. PMID:29354060

Representation of numerical magnitude in math-anxious individuals.

PubMed

Colomé, Àngels

2018-01-01

Larger distance effects in high math-anxious individuals (HMA) performing comparison tasks have previously been interpreted as indicating less precise magnitude representation in this population. A recent study by Dietrich, Huber, Moeller, and Klein limited the effects of math anxiety to symbolic comparison, in which they found larger distance effects for HMA, despite equivalent size effects. However, the question of whether distance effects in symbolic comparison reflect the properties of the magnitude representation or decisional processes is currently under debate. This study was designed to further explore the relation between math anxiety and magnitude representation through three different tasks. HMA and low math-anxious individuals (LMA) performed a non-symbolic comparison, in which no group differences were found. Furthermore, we did not replicate previous findings in an Arabic digit comparison, in which HMA individuals showed equivalent distance effects to their LMA peers. Lastly, there were no group differences in a counting Stroop task. Altogether, an explanation of math anxiety differences in terms of less precise magnitude representation is not supported.

A studentized permutation test for three-arm trials in the 'gold standard' design.

PubMed

Mütze, Tobias; Konietschke, Frank; Munk, Axel; Friede, Tim

2017-03-15

The 'gold standard' design for three-arm trials refers to trials with an active control and a placebo control in addition to the experimental treatment group. This trial design is recommended when being ethically justifiable and it allows the simultaneous comparison of experimental treatment, active control, and placebo. Parametric testing methods have been studied plentifully over the past years. However, these methods often tend to be liberal or conservative when distributional assumptions are not met particularly with small sample sizes. In this article, we introduce a studentized permutation test for testing non-inferiority and superiority of the experimental treatment compared with the active control in three-arm trials in the 'gold standard' design. The performance of the studentized permutation test for finite sample sizes is assessed in a Monte Carlo simulation study under various parameter constellations. Emphasis is put on whether the studentized permutation test meets the target significance level. For comparison purposes, commonly used Wald-type tests, which do not make any distributional assumptions, are included in the simulation study. The simulation study shows that the presented studentized permutation test for assessing non-inferiority in three-arm trials in the 'gold standard' design outperforms its competitors, for instance the test based on a quasi-Poisson model, for count data. The methods discussed in this paper are implemented in the R package ThreeArmedTrials which is available on the comprehensive R archive network (CRAN). Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Best Bang for the Buck: Part 1 – The Size of Experiments Relative to Design Performance

DOE PAGES

Anderson-Cook, Christine Michaela; Lu, Lu

2016-10-01

There are many choices to make, when designing an experiment for a study, such as: what design factors to consider, which levels of the factors to use and which model to focus on. One aspect of design, however, is often left unquestioned: the size of the experiment. When learning about design of experiments, problems are often posed as "select a design for a particular objective with N runs." It’s tempting to consider the design size as a given constraint in the design-selection process. If you think of learning through designed experiments as a sequential process, however, strategically planning for themore » use of resources at different stages of data collection can be beneficial: Saving experimental runs for later is advantageous if you can efficiently learn with less in the early stages. Alternatively, if you’re too frugal in the early stages, you might not learn enough to proceed confidently with the next stages. Therefore, choosing the right-sized experiment is important—not too large or too small, but with a thoughtful balance to maximize the knowledge gained given the available resources. It can be a great advantage to think about the design size as flexible and include it as an aspect for comparisons. Sometimes you’re asked to provide a small design that is too ambitious for the goals of the study. Finally, if you can show quantitatively how the suggested design size might be inadequate or lead to problems during analysis—and also offer a formal comparison to some alternatives of different (likely larger) sizes—you may have a better chance to ask for additional resources to deliver statistically sound and satisfying results« less

Influence of Study Design on Outcomes Following Reflexology Massage: An Integrative and Critical Review of Interventional Studies.

PubMed

McVicar, Andrew; Greenwood, Christina; Ellis, Carol; LeForis, Chantelle

2016-09-01

Interpretation of the efficacy of reflexology is hindered by inconsistent research designs and complicated by professional views that criteria of randomized controlled trials (RCTs)are not ideal to research holistic complementary and alternative medicine practice. The influence of research designs on study outcomes is not known. This integrative review sought to evaluate this possibility. Thirty-seven interventional studies (2000-2014) were identified; they had RCT or non-RCT design and compared reflexology outcomes against a control/comparison group. Viability of integrating RCT and non-RCT studies into a single database was first evaluated by appraisal of 16 reporting fields related to study setting and objectives, sample demographics, methodologic design, and treatment fidelity and assessment against Jadad score quality criteria for RCTs. For appraisal, the database was stratified into RCT/non-RCT or Jadad score of 3 or more or less than 3. Deficits in reporting were identified for blind assignment of participants, dropout/completion rate, and School of Reflexology. For comparison purposes, these fields were excluded from subsequent analysis for evidence of association between design fields and of fields with study outcomes. Thirty-one studies applied psychometric tools and 20 applied biometric tools (14 applied both). A total of 116 measures were used. Type of measure was associated with study objectives (p < 0.001; chi-square), in particular of psychometric measures with a collated "behavioral/cognitive" objective. Significant outcomes were more likely (p < 0.001; chi-square) for psychometric than for biometric measures. Neither type of outcome was associated with choice of RCT or non-RCT method, but psychometric responses were associated (p = 0.007) with a nonmassage control strategy. The review supports psychometric responses to reflexology when study design uses a nonmassage control strategy. Findings suggest that an evaluation of outcomes against sham reflexology massage and other forms of massage, as well as a narrower focus of study objective, may clarify whether there is a relationship between study design and efficacy of reflexology.

(PRESENTED NAQC SAN FRANCISCO, CA) COARSE PM METHODS STUDY: STUDY DESIGN AND RESULTS

EPA Science Inventory

Comprehensive field studies were conducted to evaluate the performance of sampling methods for measuring the coarse fraction of PM10 in ambient air. Five separate sampling approaches were evaluated at each of three sampling sites. As the primary basis of comparison, a discrete ...

Abstinence, Social Norms, and Drink Responsibly Messages: A Comparison Study

ERIC Educational Resources Information Center

Glassman, Tavis J.; Kruger, Jessica Sloan; Deakins, Bethany A.; Paprzycki, Peter; Blavos, Alexis A.; Hutzelman, Erin N.; Diehr, Aaron

2016-01-01

Objective: The purpose of this study was to determine which type of prevention message (abstinence, social norms, or responsible drinking) was most effective at reducing alcohol consumption. Participants: The subjects from this study included 194 college students from a public university. Methods: Researchers employed a quasi-experimental design,…

Multiple comparisons in drug efficacy studies: scientific or marketing principles?

PubMed

Leo, Jonathan

2004-01-01

When researchers design an experiment to compare a given medication to another medication, a behavioral therapy, or a placebo, the experiment often involves numerous comparisons. For instance, there may be several different evaluation methods, raters, and time points. Although scientifically justified, such comparisons can be abused in the interests of drug marketing. This article provides two recent examples of such questionable practices. The first involves the case of the arthritis drug celecoxib (Celebrex), where the study lasted 12 months but the authors only presented 6 months of data. The second case involves the NIMH Multimodal Treatment Study (MTA) study evaluating the efficacy of stimulant medication for attention-deficit hyperactivity disorder where ratings made by several groups are reported in contradictory fashion. The MTA authors have not clarified the confusion, at least in print, suggesting that the actual findings of the study may have played little role in the authors' reported conclusions.

Research design considerations for single-dose analgesic clinical trials in acute pain: IMMPACT recommendations.

PubMed

Cooper, Stephen A; Desjardins, Paul J; Turk, Dennis C; Dworkin, Robert H; Katz, Nathaniel P; Kehlet, Henrik; Ballantyne, Jane C; Burke, Laurie B; Carragee, Eugene; Cowan, Penney; Croll, Scott; Dionne, Raymond A; Farrar, John T; Gilron, Ian; Gordon, Debra B; Iyengar, Smriti; Jay, Gary W; Kalso, Eija A; Kerns, Robert D; McDermott, Michael P; Raja, Srinivasa N; Rappaport, Bob A; Rauschkolb, Christine; Royal, Mike A; Segerdahl, Märta; Stauffer, Joseph W; Todd, Knox H; Vanhove, Geertrui F; Wallace, Mark S; West, Christine; White, Richard E; Wu, Christopher

2016-02-01

This article summarizes the results of a meeting convened by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) on key considerations and best practices governing the design of acute pain clinical trials. We discuss the role of early phase clinical trials, including pharmacokinetic-pharmacodynamic (PK-PD) trials, and the value of including both placebo and active standards of comparison in acute pain trials. This article focuses on single-dose and short-duration trials with emphasis on the perioperative and study design factors that influence assay sensitivity. Recommendations are presented on assessment measures, study designs, and operational factors. Although most of the methodological advances have come from studies of postoperative pain after dental impaction, bunionectomy, and other surgeries, the design considerations discussed are applicable to many other acute pain studies conducted in different settings.

Comparison of intra-articular injections of hyaluronic acid and corticosteroid in the treatment of osteoarthritis of the hip in comparison with intra-articular injections of bupivacaine. Design of a prospective, randomized, controlled study with blinding of the patients and outcome assessors.

PubMed

Colen, Sascha; van den Bekerom, Michel P J; Bellemans, Johan; Mulier, Michiel

2010-11-16

Although intra-articular hyaluronic acid is well established as a treatment for osteoarthritis of the knee, its use in hip osteoarthritis is not based on large randomized controlled trials. There is a need for more rigorously designed studies on hip osteoarthritis treatment as this subject is still very much under debate. Randomized, controlled trial with a three-armed, parallel-group design. Approximately 315 patients complying with the inclusion and exclusion criteria will be randomized into one of the following treatment groups: infiltration of the hip joint with hyaluronic acid, with a corticosteroid or with 0.125% bupivacaine.The following outcome measure instruments will be assessed at baseline, i.e. before the intra-articular injection of one of the study products, and then again at six weeks, 3 and 6 months after the initial injection: Pain (100 mm VAS), Harris Hip Score and HOOS, patient assessment of their clinical status (worse, stable or better then at the time of enrollment) and intake of pain rescue medication (number per week). In addition patients will be asked if they have complications/adverse events. The six-month follow-up period for all patients will begin on the date the first injection is administered. This randomized, controlled, three-arm study will hopefully provide robust information on two of the intra-articular treatments used in hip osteoarthritis, in comparison to bupivacaine. NCT01079455.

Gender Differences in Predictors of Suicidal Thoughts and Attempts Among Homeless Veterans that Abuse Substances

ERIC Educational Resources Information Center

Benda, Brent B.

2005-01-01

This study of 315 male and 310 female homeless military veterans in a V.A. inpatient program designed to treat substance abusers, many of whom also suffer psychiatric disorders, was designed to examine gender differences in factors associated with the odds of having suicidal thoughts, and of attempting suicide, in comparison to being nonsuicidal.…

A Comparison of Single Sample and Bootstrap Methods to Assess Mediation in Cluster Randomized Trials

ERIC Educational Resources Information Center

Pituch, Keenan A.; Stapleton, Laura M.; Kang, Joo Youn

2006-01-01

A Monte Carlo study examined the statistical performance of single sample and bootstrap methods that can be used to test and form confidence interval estimates of indirect effects in two cluster randomized experimental designs. The designs were similar in that they featured random assignment of clusters to one of two treatment conditions and…

Using an Evidential Reasoning Approach for Portfolio Assessments in a Project-Based Learning Engineering Design Course

ERIC Educational Resources Information Center

Jaeger, Martin; Adair, Desmond

2015-01-01

The purpose of this study is to analyse the feasibility of an evidential reasoning (ER) method for portfolio assessments and comparison of the results found with those based on a traditional holistic judgement. An ER approach has been incorporated into portfolio assessment of an undergraduate engineering design course delivered as a project-based…

Measurement of health outcomes.

PubMed

Thavorncharoensap, Montarat

2014-05-01

Health outcomes are one of the most important components of health technology assessments (HTAs). All HTA outcomes should be measured from a relevant sample using a properly designed study and method. A number of recommendations on health outcome measurements are made in this second edition of Thailand's HTA guidelines. In particular the use of final outcomes, rather than surrogate outcomes, in HTAs is stressed. Where surrogate outcomes are used, strong justification and evidence must be provided. Effectiveness is preferred over efficacy. The relative treatment effect (the difference between health outcome that would be experienced by patients receiving the technology and that experienced by the same group were they to receive an alternative technology) should be derived from a systematic review of head-to-head RCTs. Mixed treatment comparison (MTC) should be used only to provide supplementary data that cannot be obtained from a head-to-head comparison. Where no direct comparison evidence exists, indirect comparison and observational study data can be used.

A comparative study of enzyme immobilization strategies for multi-walled carbon nanotube glucose biosensors

NASA Astrophysics Data System (ADS)

Shi, Jin; Claussen, Jonathan C.; McLamore, Eric S.; Haque, Aeraj ul; Jaroch, David; Diggs, Alfred R.; Calvo-Marzal, Percy; Rickus, Jenna L.; Porterfield, D. Marshall

2011-09-01

This work addresses the comparison of different strategies for improving biosensor performance using nanomaterials. Glucose biosensors based on commonly applied enzyme immobilization approaches, including sol-gel encapsulation approaches and glutaraldehyde cross-linking strategies, were studied in the presence and absence of multi-walled carbon nanotubes (MWNTs). Although direct comparison of design parameters such as linear range and sensitivity is intuitive, this comparison alone is not an accurate indicator of biosensor efficacy, due to the wide range of electrodes and nanomaterials available for use in current biosensor designs. We proposed a comparative protocol which considers both the active area available for transduction following nanomaterial deposition and the sensitivity. Based on the protocol, when no nanomaterials were involved, TEOS/GOx biosensors exhibited the highest efficacy, followed by BSA/GA/GOx and TMOS/GOx biosensors. A novel biosensor containing carboxylated MWNTs modified with glucose oxidase and an overlying TMOS layer demonstrated optimum efficacy in terms of enhanced current density (18.3 ± 0.5 µA mM - 1 cm - 2), linear range (0.0037-12 mM), detection limit (3.7 µM), coefficient of variation (2%), response time (less than 8 s), and stability/selectivity/reproducibility. H2O2 response tests demonstrated that the most possible reason for the performance enhancement was an increased enzyme loading. This design is an excellent platform for versatile biosensing applications.

A DUST-SETTLING CHAMBER FOR SAMPLING-INSTRUMENT COMPARISON STUDIES

EPA Science Inventory

Introduction: Few methods exist that can evenly and reproducibly deposit dusts onto surfaces for surface-sampling methodological studies. A dust-deposition chamber was designed for that purpose.

Methods: A 1-m3 Rochester-type chamber was modified to produce high airborne d...

Composite panel development at JPL

NASA Technical Reports Server (NTRS)

Mcelroy, Paul; Helms, Rich

1988-01-01

Parametric computer studies can be use in a cost effective manner to determine optimized composite mirror panel designs. An InterDisciplinary computer Model (IDM) was created to aid in the development of high precision reflector panels for LDR. The materials properties, thermal responses, structural geometries, and radio/optical precision are synergistically analyzed for specific panel designs. Promising panels designs are fabricated and tested so that comparison with panel test results can be used to verify performance prediction models and accommodate design refinement. The iterative approach of computer design and model refinement with performance testing and materials optimization has shown good results for LDR panels.

Statistical power for the comparative regression discontinuity design with a nonequivalent comparison group.

PubMed

Tang, Yang; Cook, Thomas D; Kisbu-Sakarya, Yasemin

2018-03-01

In the "sharp" regression discontinuity design (RD), all units scoring on one side of a designated score on an assignment variable receive treatment, whereas those scoring on the other side become controls. Thus the continuous assignment variable and binary treatment indicator are measured on the same scale. Because each must be in the impact model, the resulting multi-collinearity reduces the efficiency of the RD design. However, untreated comparison data can be added along the assignment variable, and a comparative regression discontinuity design (CRD) is then created. When the untreated data come from a non-equivalent comparison group, we call this CRD-CG. Assuming linear functional forms, we show that power in CRD-CG is (a) greater than in basic RD; (b) less sensitive to the location of the cutoff and the distribution of the assignment variable; and that (c) fewer treated units are needed in the basic RD component within the CRD-CG so that savings can result from having fewer treated cases. The theory we develop is used to make numerical predictions about the efficiency of basic RD and CRD-CG relative to each other and to a randomized control trial. Data from the National Head Start Impact study are used to test these predictions. The obtained estimates are closer to the predicted parameters for CRD-CG than for basic RD and are generally quite close to the parameter predictions, supporting the emerging argument that CRD should be the design of choice in many applications for which basic RD is now used. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Detailed Modeling of Distillation Technologies for Closed-Loop Water Recovery Systems

NASA Technical Reports Server (NTRS)

Allada, Rama Kumar; Lange, Kevin E.; Anderson, Molly S.

2011-01-01

Detailed chemical process simulations are a useful tool in designing and optimizing complex systems and architectures for human life support. Dynamic and steady-state models of these systems help contrast the interactions of various operating parameters and hardware designs, which become extremely useful in trade-study analyses. NASA?s Exploration Life Support technology development project recently made use of such models to compliment a series of tests on different waste water distillation systems. This paper presents efforts to develop chemical process simulations for three technologies: the Cascade Distillation System (CDS), the Vapor Compression Distillation (VCD) system and the Wiped-Film Rotating Disk (WFRD) using the Aspen Custom Modeler and Aspen Plus process simulation tools. The paper discusses system design, modeling details, and modeling results for each technology and presents some comparisons between the model results and recent test data. Following these initial comparisons, some general conclusions and forward work are discussed.

Comparison of linear synchronous and induction motors

DOT National Transportation Integrated Search

2004-06-01

A propulsion prade study was conducted as part of the Colorado Maglev Project of FTA's Urban Maglev Technology Development Program to identify and evaluate prospective linear motor designs that could potentially meet the system performance requiremen...

Enhancing staff attitudes, knowledge and skills in supporting the self-determination of adults with intellectual disability in residential settings in Hong Kong: a pretest-posttest comparison group design.

PubMed

Wong, P K S; Wong, D F K

2008-03-01

The ecological perspective recognizes the critical role that is played by rehabilitation personnel in helping people with intellectual disability (ID) to exercise self-determination, particularly in residential settings. In Hong Kong, the authors developed the first staff training programme of its kind to strengthen the competence of personnel in this area. The purpose of this study was to examine the effectiveness of staff training in enhancing residential staff's attitudes, knowledge and facilitation skills in assisting residents with ID to exercise self-determination. A pretest-posttest comparison group design was adopted. Thirty-two participants in an experimental group attended a six-session staff training programme. A 34-item self-constructed scale was designed and used for measuring the effectiveness of the staff training. The results showed that the experimental group achieved statistically significant positive changes in all domains, whereas no significant changes were found in the comparison group. The findings provided initial evidence of the effectiveness of staff training that uses an interactional attitude-knowledge-skills model for Chinese rehabilitation personnel. The factors that contributed to its effectiveness were discussed and recommendations for future research were made.

Reduction of magnetic field fluctuations in powered magnets for NMR using inductive measurements and sampled-data feedback control.

PubMed

Li, Mingzhou; Schiano, Jeffrey L; Samra, Jenna E; Shetty, Kiran K; Brey, William W

2011-10-01

Resistive and hybrid (resistive/superconducting) magnets provide substantially higher magnetic fields than those available in low-temperature superconducting magnets, but their relatively low spatial homogeneity and temporal field fluctuations are unacceptable for high resolution NMR. While several techniques for reducing temporal fluctuations have demonstrated varying degrees of success, this paper restricts attention to methods that utilize inductive measurements and feedback control to actively cancel the temporal fluctuations. In comparison to earlier studies using analog proportional control, this paper shows that shaping the controller frequency response results in significantly higher reductions in temporal fluctuations. Measurements of temporal fluctuation spectra and the frequency response of the instrumentation that cancels the temporal fluctuations guide the controller design. In particular, we describe a sampled-data phase-lead-lag controller that utilizes the internal model principle to selectively attenuate magnetic field fluctuations caused by the power supply ripple. We present a quantitative comparison of the attenuation in temporal fluctuations afforded by the new design and a proportional control design. Metrics for comparison include measurements of the temporal fluctuations using Faraday induction and observations of the effect that the fluctuations have on nuclear resonance measurements. Copyright © 2011. Published by Elsevier Inc.

Engrained experience--a comparison of microclimate perception schemata and microclimate measurements in Dutch urban squares.

PubMed

Lenzholzer, Sanda

2010-03-01

Acceptance of public spaces is often guided by perceptual schemata. Such schemata also seem to play a role in thermal comfort and microclimate experience. For climate-responsive design with a focus on thermal comfort it is important to acquire knowledge about these schemata. For this purpose, perceived and "real" microclimate situations were compared for three Dutch urban squares. People were asked about their long-term microclimate perceptions, which resulted in "cognitive microclimate maps". These were compared with mapped microclimate data from measurements representing the common microclimate when people stay outdoors. The comparison revealed some unexpected low matches; people clearly overestimated the influence of the wind. Therefore, a second assumption was developed: that it is the more salient wind situations that become engrained in people's memory. A comparison using measurement data from windy days shows better matches. This suggests that these more salient situations play a role in the microclimate schemata that people develop about urban places. The consequences from this study for urban design are twofold. Firstly, urban design should address not only the "real" problems, but, more prominently, the "perceived" problems. Secondly, microclimate simulations addressing thermal comfort issues in urban spaces should focus on these perceived, salient situations.

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

Anderson-Cook, Christine Michaela; Lu, Lu

There are many choices to make, when designing an experiment for a study, such as: what design factors to consider, which levels of the factors to use and which model to focus on. One aspect of design, however, is often left unquestioned: the size of the experiment. When learning about design of experiments, problems are often posed as "select a design for a particular objective with N runs." It’s tempting to consider the design size as a given constraint in the design-selection process. If you think of learning through designed experiments as a sequential process, however, strategically planning for themore » use of resources at different stages of data collection can be beneficial: Saving experimental runs for later is advantageous if you can efficiently learn with less in the early stages. Alternatively, if you’re too frugal in the early stages, you might not learn enough to proceed confidently with the next stages. Therefore, choosing the right-sized experiment is important—not too large or too small, but with a thoughtful balance to maximize the knowledge gained given the available resources. It can be a great advantage to think about the design size as flexible and include it as an aspect for comparisons. Sometimes you’re asked to provide a small design that is too ambitious for the goals of the study. Finally, if you can show quantitatively how the suggested design size might be inadequate or lead to problems during analysis—and also offer a formal comparison to some alternatives of different (likely larger) sizes—you may have a better chance to ask for additional resources to deliver statistically sound and satisfying results« less

Coupled Solid Rocket Motor Ballistics and Trajectory Modeling for Higher Fidelity Launch Vehicle Design

NASA Technical Reports Server (NTRS)

Ables, Brett

2014-01-01

Multi-stage launch vehicles with solid rocket motors (SRMs) face design optimization challenges, especially when the mission scope changes frequently. Significant performance benefits can be realized if the solid rocket motors are optimized to the changing requirements. While SRMs represent a fixed performance at launch, rapid design iterations enable flexibility at design time, yielding significant performance gains. The streamlining and integration of SRM design and analysis can be achieved with improved analysis tools. While powerful and versatile, the Solid Performance Program (SPP) is not conducive to rapid design iteration. Performing a design iteration with SPP and a trajectory solver is a labor intensive process. To enable a better workflow, SPP, the Program to Optimize Simulated Trajectories (POST), and the interfaces between them have been improved and automated, and a graphical user interface (GUI) has been developed. The GUI enables real-time visual feedback of grain and nozzle design inputs, enforces parameter dependencies, removes redundancies, and simplifies manipulation of SPP and POST's numerous options. Automating the analysis also simplifies batch analyses and trade studies. Finally, the GUI provides post-processing, visualization, and comparison of results. Wrapping legacy high-fidelity analysis codes with modern software provides the improved interface necessary to enable rapid coupled SRM ballistics and vehicle trajectory analysis. Low cost trade studies demonstrate the sensitivities of flight performance metrics to propulsion characteristics. Incorporating high fidelity analysis from SPP into vehicle design reduces performance margins and improves reliability. By flying an SRM designed with the same assumptions as the rest of the vehicle, accurate comparisons can be made between competing architectures. In summary, this flexible workflow is a critical component to designing a versatile launch vehicle model that can accommodate a volatile mission scope.

Adaptation of object descriptions to a partner under increasing communicative demands: a comparison of children with and without autism.

PubMed

Nadig, Aparna; Vivanti, Giacomo; Ozonoff, Sally

2009-12-01

This study compared the object descriptions of school-age children with high-functioning autism (HFA) with those of a matched group of typically developing children. Descriptions were elicited in a referential communication task where shared information was manipulated, and in a guessing game where clues had to be provided about the identity of an object that was hidden from the addressee. Across these tasks, increasingly complex levels of audience design were assessed: (1) the ability to give adequate descriptions from one's own perspective, (2) the ability to adjust descriptions to an addressee's perspective when this differs from one's own, and (3) the ability to provide indirect yet identifying descriptions in a situation where explicit labeling is inappropriate. Results showed that there were group differences in all three cases, with the HFA group giving less efficient descriptions with respect to the relevant context than the comparison group. More revealing was the identification of distinct adaptation profiles among the HFA participants: those who had difficulty with all three levels, those who displayed Level 1 audience design but poor Level 2 and Level 3 design, and those demonstrated all three levels of audience design, like the majority of the comparison group. Higher structural language ability, rather than symptom severity or social skills, differentiated those HFA participants with typical adaptation profiles from those who displayed deficient audience design, consistent with previous reports of language use in autism.

Developmental Therapeutics Consortium report on study design effects on trial outcomes in chronic myeloid leukaemia.

PubMed

Giles, Francis; Mahon, François-Xavier; Gjertsen, Bjorn; Swords, Ronan; Labar, Boris; Turkina, Anna; Rosti, Gianantonio

2012-09-01

Tyrosine kinase inhibitors (TKIs) have dramatically changed the treatment of chronic myeloid leukaemia (CML). Results from ongoing phase 3 trials with nilotinib [Efficacy and Safety in Clinical Trials-Newly Diagnosed Patients (ENESTnd)] and dasatinib [Dasatinib Versus Imatinib Study in Treatment-Naive CML-CP Patients (DASISION)] in newly diagnosed patients with CML in chronic phase have demonstrated that these TKIs resulted in significant improvements in responses vs. imatinib. The Developmental Therapeutics Consortium (DTC) systematically reviewed the published literature to provide a comparative analysis of the ENESTnd and DASISION trial designs and data reported on each study. The recent approval of nilotinib and dasatinib based on these two pivotal studies offers physicians the option to optimise frontline treatment based on a patient's comorbidities, risk factors and tolerability profiles. Although nilotinib and dasatinib provide effective therapeutic options for the frontline treatment of CML, the lack of an evidenced-based, side-by-side comparison makes it difficult to directly compare these agents. Despite potential bias from differences in patient populations and study design, indirect cross-trial comparisons to determine the relative effectiveness of these agents will be performed by physicians. This DTC report provides a comprehensive summary of the study designs, protocols and results of the ENESTnd and DASISION trials, which will assist physicians in making informed decisions on the best treatment approach for their patients. © 2012 The Authors. European Journal of Clinical Investigation © 2012 Stichting European Society for Clinical Investigation Journal Foundation.

The common case study: Lockheed design of a supersonic cruise vehicle

NASA Technical Reports Server (NTRS)

Clauss, J. S., Jr.; Hays, A. P.; Wilson, J. R.

1978-01-01

The objective was to compare the characteristics of SSTs designed for the same mission by Lockheed, McDonnell Douglas, British Aerospace (U.K.), Aerospatiale (France), and the USSR. This comparison was to be used to calibrate parametric design studies of the tradeoff between SST direct operating cost (DOC) and noise levels at the FAR 36 certification points. The guidelines for this common case study were to design an aircraft with the following mission: payload 23 247 kg (51 250 lbm), range - 7000 km (3780 n. mi.), and cruise Mach number - 2.2. Field length was constrained to 3505 m (11 500 ft). Other airfield constraints and fuel reserves were also specified, but no noise constraints were applied.

Toward crustacean without chemicals: a descriptive analysis of consumer response using price comparisons

PubMed Central

Okpala, Charles Odilichukwu R.; Bono, Gioacchino; Pipitone, Vito; Vitale, Sergio; Cannizzaro, Leonardo

2016-01-01

Background To date, there seems to be limited-to-zero emphasis about how consumers perceive crustacean products subject to either chemical and or non-chemical preservative treatments. In addition, studies that investigated price comparisons of crustacean products subject to either chemical or chemical-free preservative methods seem unreported. Objective This study focused on providing some foundational knowledge about how consumers perceive traditionally harvested crustaceans that are either chemical-treated and or free of chemicals, incorporating price comparisons using a descriptive approach. Design The study design employed a questionnaire approach via interview using a computer-assisted telephone system and sampled 1,540 participants across five key locations in Italy. To actualize consumer sensitivity, ‘price’ was the focus given its crucial role as a consumption barrier. Prior to this, variables such as demographic characteristics of participants, frequency of purchasing, quality attributes/factors that limit the consumption of crustaceans were equally considered. Results By price comparisons, consumers are likely to favor chemical-free (modified atmosphere packaging) crustacean products amid a price increase of up to 15%. But, a further price increase such as by 25% could markedly damage consumers’ feelings, which might lead to a considerable number opting out in favor of either chemical-treated or other seafood products. Comparing locations, the studied variables showed no statistical differences (p>0.05). On the contrary, the response weightings fluctuated across the studied categories. Both response weightings and coefficient of variation helped reveal more about how responses deviated per variable categories. Conclusions This study has revealed some foundational knowledge about how consumers perceive traditionally harvested crustaceans that were either chemical-treated or subject to chemical-free preservative up to price sensitivity using Italy as a reference case, which is applicable to other parts of the globe. PMID:27799084

OSIRIS and SOMBRERO Inertial Fusion Power Plant Designs, Volume 2: Designs, Assessments, and Comparisons

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

Meier, W. R.; Bieri, R. L.; Monsler, M. J.

1992-03-01

This is a comprehensive design study of two Inertial Fusion Energy (IFE) electric power plants. Conceptual designs are presented for a fusion reactor (called Osiris) using an induction-linac heavy-ion beam driver, and another (called SOMBRERO) using a KrF laser driver. The designs covered all aspects of IFE power plants, including the chambers, heat transport and power conversion systems, balance-of-plant facilities, target fabrication, target injection and tracking, as well as the heavy-ion and KrF drivers. The point designs were assessed and compared in terms of their environmental & safety aspects, reliability and availability, economics, and technology development needs.

The utility of Geographical Information Systems (GIS) in systems-oriented obesity intervention projects: the selection of comparable study sites for a quasi-experimental intervention design--TX CORD.

PubMed

Oluyomi, Abiodun O; Byars, Allison; Byrd-Williams, Courtney; Sharma, Shreela V; Durand, Casey; Hoelscher, Deanna M; Butte, Nancy F; Kelder, Steven H

2015-02-01

The Texas Childhood Obesity Research Demonstration project (TX CORD) uses a systems-oriented approach to address obesity that includes individual and family interventions, community-level action, as well as environmental and policy initiatives. Given that randomization is seldom possible in community-level intervention studies, TX CORD uses a quasi-experimental design. Comparable intervention and comparison study sites are needed to address internal validity bias. TX CORD was designed to be implemented in low-income, ethnically diverse communities in Austin and Houston, Texas. A three-stage Geographical Information System (GIS) methodology was used to establish and ascertain the comparability of the intervention and comparison study sites. Census tract (stage 1) and school (stage 2) data were used to identify spatially exclusive geographic areas that were comparable. In stage 3, study sites were compared on demographic characteristics, socioeconomic status (SES), food assets, and physical activity (PA) assets. Student's t-test was used to examine significant differences between the selected sites. The methodology that was used resulted in the selection of catchment areas with demographic and socioeconomic characteristics that fit the target population: ethnically diverse population; lower-median household income; and lower home ownership rates. Additionally, the intervention and comparison sites were statistically comparable on demographic and SES variables, as well as food assets and PA assets. This GIS approach can provide researchers, program evaluators, and policy makers with useful tools for both research and practice. Area-level information that allows for robust understanding of communities can enhance analytical procedures in community health research and offer significant contributions in terms of community assessment and engagement.

An innovation in curriculum content and delivery of cancer education within undergraduate nurse training in the UK. What impact does this have on the knowledge, attitudes and confidence in delivering cancer care?

PubMed

Edwards, Deborah; Anstey, Sally; Kelly, Daniel; Hopkinson, Jane

2016-04-01

This was an evaluation of an innovation in curriculum content and delivery within undergraduate nursing education in the UK. Its purpose was to investigate the effect on knowledge, attitudes and confidence in delivering cancer care. The study design was a pre-test post-test survey design with a comparison group. Participants were two cohorts of undergraduate nursing students (n(intervention) = 84, n(comparison) = 91). The intervention cohort were exposed to a new 3.5 day programme of cancer education, coproduced with patients, carers and health professionals, which focused on cancer as a life changing long-term condition. The comparison cohort had been exposed to a 2 day programme produced by a lecturer. Following exposure to the new model for the delivery of undergraduate nurse cancer education, the intervention cohort demonstrated good overall knowledge of the impact of cancer, more positive attitudes towards cancer treatment and more confidence in their ability to deliver cancer care. Attitudes were more positive and confidence in ability to support cancer patients at all stages of the cancer journey were greater than in the comparison group. Insights gained into the cancer patient and carer perspectives were highly valued. This study has found that a new model for the delivery of cancer education focusing on survivorship and delivered in partnership with patients, carers and clinicians, may improve knowledge, attitudes and confidence in the delivery of cancer care. Further work is now needed, using a more robust experimental design, to investigate the generalisability of the results to other education programs. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Technology-enhanced simulation in emergency medicine: a systematic review and meta-analysis.

PubMed

Ilgen, Jonathan S; Sherbino, Jonathan; Cook, David A

2013-02-01

Technology-enhanced simulation is used frequently in emergency medicine (EM) training programs. Evidence for its effectiveness, however, remains unclear. The objective of this study was to evaluate the effectiveness of technology-enhanced simulation for training in EM and identify instructional design features associated with improved outcomes by conducting a systematic review. The authors systematically searched MEDLINE, EMBASE, CINAHL, ERIC, PsychINFO, Scopus, key journals, and previous review bibliographies through May 2011. Original research articles in any language were selected if they compared simulation to no intervention or another educational activity for the purposes of training EM health professionals (including student and practicing physicians, midlevel providers, nurses, and prehospital providers). Reviewers evaluated study quality and abstracted information on learners, instructional design (curricular integration, feedback, repetitive practice, mastery learning), and outcomes. From a collection of 10,903 articles, 85 eligible studies enrolling 6,099 EM learners were identified. Of these, 56 studies compared simulation to no intervention, 12 compared simulation with another form of instruction, and 19 compared two forms of simulation. Effect sizes were pooled using a random-effects model. Heterogeneity among these studies was large (I(2) ≥ 50%). Among studies comparing simulation to no intervention, pooled effect sizes were large (range = 1.13 to 1.48) for knowledge, time, and skills and small to moderate for behaviors with patients (0.62) and patient effects (0.43; all p < 0.02 except patient effects p = 0.12). Among comparisons between simulation and other forms of instruction, the pooled effect sizes were small (≤ 0.33) for knowledge, time, and process skills (all p > 0.1). Qualitative comparisons of different simulation curricula are limited, although feedback, mastery learning, and higher fidelity were associated with improved learning outcomes. Technology-enhanced simulation for EM learners is associated with moderate or large favorable effects in comparison with no intervention and generally small and nonsignificant benefits in comparison with other instruction. Future research should investigate the features that lead to effective simulation-based instructional design. © 2013 by the Society for Academic Emergency Medicine.

Children's Participation in Foster Care Hearings

ERIC Educational Resources Information Center

Weisz, Vicky; Wingrove, Twila; Beal, Sarah J.; Faith-Slaker, April

2011-01-01

Purpose: Empirical research regarding potential risks and benefits of children's participation in the legal system generally, and in the child dependency legal system in particular, is sparse and mostly characterized by small studies without comparison groups. The current study was designed to address the following questions regarding children's…

Batiendo La Olla ("Stirring the Pot"): A Cross-Generational Comparison and Self-Study by Second Generation Puerto Ricans in Philadelphia. A Final Narrative Report to "Youthgrants in the Humanities," National Endowment for the Humanities.

ERIC Educational Resources Information Center

Taller Puertorriqueno, Inc., Philadelphia, PA.

During the months from February 1977 to December 1978, Taller Puertorriqueno, Inc., conducted an oral history project to produce a cross-generational comparison of Puerto Ricans in Philadelphia (Pennsylvania). The project was designed to train young people to be perceptive human beings who were sensitive to their environment and especially aware…

Comparison of two gas chromatograph models and analysis of binary data

NASA Technical Reports Server (NTRS)

Keba, P. S.; Woodrow, P. T.

1972-01-01

The overall objective of the gas chromatograph system studies is to generate fundamental design criteria and techniques to be used in the optimum design of the system. The particular tasks currently being undertaken are the comparison of two mathematical models of the chromatograph and the analysis of binary system data. The predictions of two mathematical models, an equilibrium absorption model and a non-equilibrium absorption model exhibit the same weaknesses in their inability to predict chromatogram spreading for certain systems. The analysis of binary data using the equilibrium absorption model confirms that, for the systems considered, superposition of predicted single component behaviors is a first order representation of actual binary data. Composition effects produce non-idealities which limit the rigorous validity of superposition.

Output feedback regulator design for jet engine control systems

NASA Technical Reports Server (NTRS)

Merrill, W. C.

1977-01-01

A multivariable control design procedure based on the output feedback regulator formulation is described and applied to turbofan engine model. Full order model dynamics, were incorporated in the example design. The effect of actuator dynamics on closed loop performance was investigaged. Also, the importance of turbine inlet temperature as an element of the dynamic feedback was studied. Step responses were given to indicate the improvement in system performance with this control. Calculation times for all experiments are given in CPU seconds for comparison purposes.

Five schools of thought about complexity: Implications for design and process science

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

Warfield, J.N.

1996-12-31

The prevalence of complexity is a fact of life in virtually all aspects of system design today. Five schools of thought concerning complexity seem to be present in areas where people strive to gain more facility with difficult issues: (1) Interdisciplinary or Cross-Disciplinary {open_quotes}approaches{close_quotes} or {open_quotes}methods{close_quotes} (fostered by the Association for Integrative Studies, a predominantly liberal-arts faculty activity), (2) Systems Dynamics (fostered by Jay Forrester, Dennis Meadows, Peter Senge, and others closely associated with MIT), (3) Chaos Theory (arising in small groups in many locations), (4) Adaptive Systems Theory (predominantly associated with the Santa Fe Institute), and (5) The Structure-Basedmore » school (developed by the author, his colleagues and associates). A comparison of these five schools of thought will be offered, in order to show the implications of them upon the development and application of design and process science. The following criteria of comparison will be used: (a) how complexity is defined, (b) analysis versus synthesis, (c) potential for acquiring practical competence in coping with complexity, and (d) relationship to underlying formalisms that facilitate computer assistance in applications. Through these comparisons, the advantages and disadvantages of each school of thought can be clarified, and the possibilities of changes in the educational system to provide for the management of complexity in system design can be articulated.« less

Modeling human-machine interactions for operations room layouts

NASA Astrophysics Data System (ADS)

Hendy, Keith C.; Edwards, Jack L.; Beevis, David

2000-11-01

The LOCATE layout analysis tool was used to analyze three preliminary configurations for the Integrated Command Environment (ICE) of a future USN platform. LOCATE develops a cost function reflecting the quality of all human-human and human-machine communications within a workspace. This proof- of-concept study showed little difference between the efficacy of the preliminary designs selected for comparison. This was thought to be due to the limitations of the study, which included the assumption of similar size for each layout and a lack of accurate measurement data for various objects in the designs, due largely to their notional nature. Based on these results, the USN offered an opportunity to conduct a LOCATE analysis using more appropriate assumptions. A standard crew was assumed, and subject matter experts agreed on the communications patterns for the analysis. Eight layouts were evaluated with the concepts of coordination and command factored into the analysis. Clear differences between the layouts emerged. The most promising design was refined further by the USN, and a working mock-up built for human-in-the-loop evaluation. LOCATE was applied to this configuration for comparison with the earlier analyses.

COMPARISON OF SCREENING APPROACHES

EPA Science Inventory

Neurobehavioral techniques have been used extensively n an ma toxicology studies because, in many Gases, such procedures are designed to evaluate neurobiological functions thought to be affected in chemical-exposed humans, e.g., changes in sensorimotor function. procedures used t...

Study of Automotive Aerodynamic Drag

DOT National Transportation Integrated Search

1975-09-01

Reductions of aerodynamic drag in the 20-25% range through the use of several established drag-reduction devices and minor design changes have been demonstrated on three large sales-volume 1974 and 1975 model American automobiles. Comparisons of test...

Solar-C Conceptual Spacecraft Design Study: Final Review. Release 2

NASA Technical Reports Server (NTRS)

Hopkins, Randall; Baysinger, Mike; Thomas, Dan; Heaton, Andy; Stough, Rob; Hill, Spencer; Owens, Jerry; Young, Roy; Fabisinski, Leo; Thomas, Scott;

Anomaly Trends for Missions to Mars: Mars Global Surveyor and Mars Odyssey

NASA Technical Reports Server (NTRS)

Green, Nelson W.; Hoffman, Alan R.

2008-01-01

Conducted as a part of NASA Ultra-Reliability effort: Goal is to design for increased reliability in all NASA missions. Desire is to increase reliability by a factor of 10. Study provides a baseline for current technology. Analyzed anomalies for spacecraft orbiting Mars. Long lived spacecraft. Comparison with current rover missions and past orbiters. Looked for trends to assist design of future missions.

Reflective Analysis as a Tool for Task Redesign: The Case of Prospective Elementary Teachers Solving and Posing Fraction Comparison Problems

ERIC Educational Resources Information Center

Thanheiser, Eva; Olanoff, Dana; Hillen, Amy; Feldman, Ziv; Tobias, Jennifer M.; Welder, Rachael M.

2016-01-01

Mathematical task design has been a central focus of the mathematics education research community over the last few years. In this study, six university teacher educators from six different US institutions formed a community of practice to explore key aspects of task design (planning, implementing, reflecting, and modifying) in the context of…

Educational Game as Supplemental Learning Tool: Benefits, Challenges, and Tensions Arising from Use in an Elementary School Classroom

ERIC Educational Resources Information Center

Warren, Scott; Dondlinger, Mary Jo; Stein, Richard; Barab, Sasha

2009-01-01

This article examines the qualitative findings from a mixed-methods comparison study of the use of an online multi-user virtual environment called Anytown which supplemented face-to-face writing instruction in a fourth grade classroom to determine implications for the design of such environments and the reported impact of this design on students…

A Comparison of Kernel Equating and Traditional Equipercentile Equating Methods and the Parametric Bootstrap Methods for Estimating Standard Errors in Equipercentile Equating

ERIC Educational Resources Information Center

Choi, Sae Il

2009-01-01

This study used simulation (a) to compare the kernel equating method to traditional equipercentile equating methods under the equivalent-groups (EG) design and the nonequivalent-groups with anchor test (NEAT) design and (b) to apply the parametric bootstrap method for estimating standard errors of equating. A two-parameter logistic item response…

Simplified, inverse, ejector design tool

NASA Technical Reports Server (NTRS)

Dechant, Lawrence J.

1993-01-01

A simple lumped parameter based inverse design tool has been developed which provides flow path geometry and entrainment estimates subject to operational, acoustic, and design constraints. These constraints are manifested through specification of primary mass flow rate or ejector thrust, fully-mixed exit velocity, and static pressure matching. Fundamentally, integral forms of the conservation equations coupled with the specified design constraints are combined to yield an easily invertible linear system in terms of the flow path cross-sectional areas. Entrainment is computed by back substitution. Initial comparison with experimental and analogous one-dimensional methods show good agreement. Thus, this simple inverse design code provides an analytically based, preliminary design tool with direct application to High Speed Civil Transport (HSCT) design studies.

A meta-analysis of math performance in Turner syndrome.

PubMed

Baker, Joseph M; Reiss, Allan L

2016-02-01

Studies investigating the relationship between Turner syndrome and math learning disability have used a wide variation of tasks designed to test various aspects of mathematical competencies. Although these studies have revealed much about the math deficits common to Turner syndrome, their diversity makes comparisons between individual studies difficult. As a result, the consistency of outcomes among these diverse measures remains unknown. The overarching aim of this review is to provide a systematic meta-analysis of the differences in math and number performance between females with Turner syndrome and age-matched neurotypical peers. We provide a meta-analysis of behavioral performance in Turner syndrome relative to age-matched neurotypical populations on assessments of math and number aptitude. In total, 112 comparisons collected across 17 studies were included. Although 54% of all statistical comparisons in our analyses failed to reject the null hypothesis, our results indicate that meaningful group differences exist on all comparisons except those that do not require explicit calculation. Taken together, these results help elucidate our current understanding of math and number weaknesses in Turner syndrome, while highlighting specific topics that require further investigation. © 2015 Mac Keith Press.

Comparing State-Space Multivariable Controls to Multi-SISO Controls for Load Reduction of Drivetrain-Coupled Modes on Wind Turbines Through Field-Testing

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

Fleming, P. A.; Van Wingerden, J. W.; Wright, A. D.

2012-01-01

In this paper we present results from an ongoing controller comparison study at the National Renewable Energy Laboratory's (NREL's) National Wind Technology Center (NWTC). The intention of the study is to demonstrate the advantage of using modern multivariable methods for designing control systems for wind turbines versus conventional approaches. We will demonstrate the advantages through field-test results from experimental turbines located at the NWTC. At least two controllers are being developed side-by-side to meet an incrementally increasing number of turbine load-reduction objectives. The first, a multiple single-input, single-output (m-SISO) approach, uses separately developed decoupled and classicially tuned controllers, which is,more » to the best of our knowledge, common practice in the wind industry. The remaining controllers are developed using state-space multiple-input and multiple-output (MIMO) techniques to explicity account for coupling between loops and to optimize given known frequency structures of the turbine and disturbance. In this first publication from the study, we present the structure of the ongoing controller comparison experiment, the design process for the two controllers compared in this phase, and initial comparison results obtained in field-testing.« less

A Teaching Model for Scaffolding 4th Grade Students' Scientific Explanation Writing

NASA Astrophysics Data System (ADS)

Yang, Hsiu-Ting; Wang, Kuo-Hua

2014-08-01

Improving students scientific explanations is one major goal of science education. Both writing activities and concept mapping are reported as effective strategies for enhancing student learning of science. The purpose of this study was to examine the effect of a teaching model, named the DCI model, which integrates a Descriptive explanation writing activity, Concept mapping, and an Interpretive explanation writing activity, is introduced in a 4th grade science class to see if it would improve students' scientific explanations and understanding. A quasi-experimental design, including a non-randomized comparison group and a pre- and post-test design, was adopted for this study. An experimental group of 25 students were taught using the DCI teaching model, while a comparison group received a traditional lecture teaching. A rubric and content analysis was used to assess students' scientific explanations. The independent sample t test was used to measure difference in conceptual understanding between the two groups, before and after instruction. Then, the paired t test analysis was used to understand the promotion of the DCI teaching model. The results showed that students in the experimental group performed better than students in the comparison group, both in scientific concept understanding and explanation. Suggestions for using concept mapping and writing activities (the DCI teaching model) in science classes are provided in this study.

Recommendations of the VAC2VAC workshop on the design of multi-centre validation studies.

PubMed

Halder, Marlies; Depraetere, Hilde; Delannois, Frédérique; Akkermans, Arnoud; Behr-Gross, Marie-Emmanuelle; Bruysters, Martijn; Dierick, Jean-François; Jungbäck, Carmen; Kross, Imke; Metz, Bernard; Pennings, Jeroen; Rigsby, Peter; Riou, Patrice; Balks, Elisabeth; Dobly, Alexandre; Leroy, Odile; Stirling, Catrina

2018-03-01

Within the Innovative Medicines Initiative 2 (IMI 2) project VAC2VAC (Vaccine batch to vaccine batch comparison by consistency testing), a workshop has been organised to discuss ways of improving the design of multi-centre validation studies and use the data generated for product-specific validation purposes. Moreover, aspects of validation within the consistency approach context were addressed. This report summarises the discussions and outlines the conclusions and recommendations agreed on by the workshop participants. Copyright © 2018.

Reducing cardiovascular disease risk in mid-life and older African Americans: A church-based longitudinal intervention project at baseline

PubMed Central

Lemacks, Jennifer L.; Wickrama, Kandauda (K.A.S.); Young-Clark, Iris; Coccia, Catherine; Ilich, Jasminka Z.; Harris, Cynthia M.; Hart, Celeste B.; Battle, Arrie M.; O’Neal, Catherine Walker

2014-01-01

Introduction African Americans (AAs) experience higher age-adjusted morbidity and mortality than Whites for cardiovascular disease (CVD). Church-based health programs can reduce risk factors for CVD, including elevated blood pressure [BP], excess body weight, sedentary lifestyle and diet. Yet few studies have incorporated older adults and longitudinal designs. Purposes The aims of this study are to: a) describe a theory-driven longitudinal intervention study to reduce CVD risk in mid-life and older AAs; b) compare selected dietary (fruit and vegetable servings/day, fat consumption), physical activity (PA) and clinical variables (BMI, girth circumferences, systolic and diastolic BP, LDL, HDL, total cholesterol [CHOL] and HDL/CHOL) between treatment and comparison churches at baseline; c) identify selected background characteristics (life satisfaction, social support, age, gender, educational level, marital status, living arrangement and medication use) at baseline that may confound results; and d) share the lessons learned. Methods This study incorporated a longitudinal pre/post with comparison group quasi-experimental design. Community-based participatory research (CBPR) was used to discover ideas for the study, identify community advisors, recruit churches (three treatment, three comparison) in two-counties in North Florida, and randomly select 221 mid-life and older AAs (45+) (n = 104 in clinical subsample), stratifying for age and gender. Data were collected through self-report questionnaires and clinical assessments. Results and conclusions Dietary, PA and clinical results were similar to the literature. Treatment and comparison groups were similar in background characteristics and health behaviors but differed in selected clinical factors. For the total sample, relationships were noted for most of the background characteristics. Lessons learned focused on community relationships and participant recruitment. PMID:24685998

Moderating the stereotypical views of health and social care students: the role of interprofessional education.

PubMed

Foster, Rebecca; Macleod Clark, Jill

2015-01-01

The potential of interprofessional education (IPE) to influence the perceptions and attitudes of health and social care professionals towards their colleagues in other disciplines is well recognized. However, empirical evidence for the positive impact of IPE on stereotypical beliefs has been limited. We report the findings of a pioneering, large scale study designed to assess the influence of IPE on these beliefs. A pre-test, post-test, quasi experimental design compared students' stereotypical views at the beginning and end of undergraduate studies. 580 students from 10 health and social care professional groups undertook assessed IPE modules over 3 years (the intervention group). Baseline and post-course stereotype ratings were compared with those of 672 students in a comparison group, not exposed to IPE modules. Baseline stereotype profiles showed clear variations in the way different professions were perceived, indicating stereotypical beliefs about the characteristics of each profession. Rating patterns were similar for intervention and comparison groups. At graduation, only minor changes were observed in the overall rating patterns for both groups. However, more ratings had decreased in the intervention group than the comparison group, suggesting that IPE may play a role in moderating more extreme stereotyping of colleagues in other professions.

Efficacy of Visual-Acoustic Biofeedback Intervention for Residual Rhotic Errors: A Single-Subject Randomization Study

ERIC Educational Resources Information Center

Byun, Tara McAllister

2017-01-01

Purpose: This study documented the efficacy of visual-acoustic biofeedback intervention for residual rhotic errors, relative to a comparison condition involving traditional articulatory treatment. All participants received both treatments in a single-subject experimental design featuring alternating treatments with blocked randomization of…

Incidental Becomes Visible: A Comparison of School- and Community-Based Field Experience Narratives

ERIC Educational Resources Information Center

Holder, K. C.; Downey, Jayne A.

2008-01-01

The purpose of this study was to describe and compare student learning documented using written field experience summary narratives and occurring in community-based or school-based locations. Utilizing a hybrid portraiture--instrumental case study design, two researchers selected participants from undergraduate educational psychology courses using…

Economic Valuation of Air Force Environmental Resources: A Contingent Valuation Case Study.

DTIC Science & Technology

1996-12-01

Empirical Measures of Welfare Change: A Comparison of Non-market Techniques," Land Economics: 156-175 (Vol. 61, No. 2, 1985). Sen , Amartya K...shackles of the traditional [observed] approach" ( Sen , 1977). The flexibility of a properly designed contingent valuation study allows CVM to measure

A Comparison of Colour and Black and White T. V.

ERIC Educational Resources Information Center

Reich, Carol; Meisner, Alan

The relative educational effectiveness of color vs. black and white television has not been exhaustively explored. While previous studies have concentrated on the factual retention of subject matter--bypassing the subjective attitudes--this study was designed to thoroughly analyze both areas. Using Osgood's Semantic Differential and the Liking…

The Effectiveness of Interactive Instructional Practices on Content Area Reading Comprehension.

ERIC Educational Resources Information Center

Bos, Candace S.; Anders, Patricia L.

Four studies conducted over a 2-year period systematically evaluated the effectiveness of interactive instructional practices in the vocabulary learning and reading comprehension of learning disabled students. The design of the four studies was similar in that comparisons were made among three different interactive teaching strategies (semantic…

Web Sites for Every Department Course

ERIC Educational Resources Information Center

Naveh, Gali; Tubin, Dorit; Pliskin, Nava

2006-01-01

Purpose: To study the implementation of a learning content management system (LCMS) at one department of a university in light of Rogers' diffusion of innovation (DOI) theory and in comparison to known critical success factors (CSFs) in implementation of information systems. Design/methodology/approach: A case study approach was used to examine…

Reading and Writing as Academic Literacy in EAP Program of Indonesian Leaners

ERIC Educational Resources Information Center

Solikhah, Imroatus

2015-01-01

This study investigates academic literacy imposed in reading and writing for academic purposes in the EAP program. This study uses descriptive design elaborating data from curriculum documents and interviews. Involving 45 participants from IAIN Surakarta and Veteran University, data were analyzed using constant-comparison and inductive analysis…

Programme Content Orientation in Vocational Education and Training and Life Chances--A Comparative Study

ERIC Educational Resources Information Center

Kap, Hrvoje

2014-01-01

Comparative studies of vocational education and training systems rarely conduct systematic comparisons of the content of educational programmes, partly because of methodological difficulties. Yet, comparing the organisation of curricula can increase our understanding of how programme design reflects orientation towards various life chances in…

Study designs, use of statistical tests, and statistical analysis software choice in 2015: Results from two Pakistani monthly Medline indexed journals.

PubMed

Shaikh, Masood Ali

2017-09-01

Assessment of research articles in terms of study designs used, statistical tests applied and the use of statistical analysis programmes help determine research activity profile and trends in the country. In this descriptive study, all original articles published by Journal of Pakistan Medical Association (JPMA) and Journal of the College of Physicians and Surgeons Pakistan (JCPSP), in the year 2015 were reviewed in terms of study designs used, application of statistical tests, and the use of statistical analysis programmes. JPMA and JCPSP published 192 and 128 original articles, respectively, in the year 2015. Results of this study indicate that cross-sectional study design, bivariate inferential statistical analysis entailing comparison between two variables/groups, and use of statistical software programme SPSS to be the most common study design, inferential statistical analysis, and statistical analysis software programmes, respectively. These results echo previously published assessment of these two journals for the year 2014.

General university requirements and holistic development in university students in Hong Kong.

PubMed

Shek, Daniel T L; Yu, Lu

2017-02-01

The General University Requirements (GUR) at The Hong Kong Polytechnic University (PolyU) is an integral part of the new 4-year undergraduate curriculum which attempts to promote holistic student development. To evaluate the effectiveness of the GUR, a study adopting a static group comparison design was conducted, with a sample of Year 3 PolyU students studied in the 4-year undergraduate degree program (n=566) compared with a control Year 3 sample recruited from a comparable university in Hong Kong (n=285). The students in both samples responded to measures on empathy, positive youth development, and engagement in university study. Results showed that although both groups basically did not differ in the major background demographic variables, PolyU students performed better than did the students of the control group on measures of holistic development. Bearing in mind the intrinsic problems of the static comparison group design, the present findings provide support for the effectiveness of the GUR at PolyU.

Implementation of a combined algorithm designed to increase the reliability of information systems: simulation modeling

NASA Astrophysics Data System (ADS)

Popov, A.; Zolotarev, V.; Bychkov, S.

2016-11-01

This paper examines the results of experimental studies of a previously submitted combined algorithm designed to increase the reliability of information systems. The data that illustrates the organization and conduct of the studies is provided. Within the framework of a comparison of As a part of the study conducted, the comparison of the experimental data of simulation modeling and the data of the functioning of the real information system was made. The hypothesis of the homogeneity of the logical structure of the information systems was formulated, thus enabling to reconfigure the algorithm presented, - more specifically, to transform it into the model for the analysis and prediction of arbitrary information systems. The results presented can be used for further research in this direction. The data of the opportunity to predict the functioning of the information systems can be used for strategic and economic planning. The algorithm can be used as a means for providing information security.

Development of low-shock pyrotechnic separation nuts. [design performance of flight type nuts

NASA Technical Reports Server (NTRS)

Bement, L. J.; Neubert, V. H.

1973-01-01

Performance demonstrations and comparisons were made on six flight type pyrotechnic separation nut designs, two of which are standard designs in current use, and four of which were designed to produce low shock on actuation. Although the shock performances of the four low shock designs are considerably lower than the standard designs, some penalties may be incurred in increased volume, weight, or complexity. These nuts, and how they are installed, can significantly influence the pyrotechnic shock created in spacecraft structures. A high response monitoring system has been developed and demonstrated to provide accurate performance comparisons for pyrotechnic separation nuts.

Quantitative Comparison of Minimum Inductance and Minimum Power Algorithms for the Design of Shim Coils for Small Animal Imaging

PubMed Central

HUDSON, PARISA; HUDSON, STEPHEN D.; HANDLER, WILLIAM B.; SCHOLL, TIMOTHY J.; CHRONIK, BLAINE A.

2010-01-01

High-performance shim coils are required for high-field magnetic resonance imaging and spectroscopy. Complete sets of high-power and high-performance shim coils were designed using two different methods: the minimum inductance and the minimum power target field methods. A quantitative comparison of shim performance in terms of merit of inductance (ML) and merit of resistance (MR) was made for shim coils designed using the minimum inductance and the minimum power design algorithms. In each design case, the difference in ML and the difference in MR given by the two design methods was <15%. Comparison of wire patterns obtained using the two design algorithms show that minimum inductance designs tend to feature oscillations within the current density; while minimum power designs tend to feature less rapidly varying current densities and lower power dissipation. Overall, the differences in coil performance obtained by the two methods are relatively small. For the specific case of shim systems customized for small animal imaging, the reduced power dissipation obtained when using the minimum power method is judged to be more significant than the improvements in switching speed obtained from the minimum inductance method. PMID:20411157

Control law parameterization for an aeroelastic wind-tunnel model equipped with an active roll control system and comparison with experiment

NASA Technical Reports Server (NTRS)

Perry, Boyd, III; Dunn, H. J.; Sandford, Maynard C.

1988-01-01

Nominal roll control laws were designed, implemented, and tested on an aeroelastically-scaled free-to-roll wind-tunnel model of an advanced fighter configuration. The tests were performed in the NASA Langley Transonic Dynamics Tunnel. A parametric study of the nominal roll control system was conducted. This parametric study determined possible control system gain variations which yielded identical closed-loop stability (roll mode pole location) and identical roll response but different maximum control-surface deflections. Comparison of analytical predictions with wind-tunnel results was generally very good.

The pitfalls of platform comparison: DNA copy number array technologies assessed

PubMed Central

2009-01-01

Background The accurate and high resolution mapping of DNA copy number aberrations has become an important tool by which to gain insight into the mechanisms of tumourigenesis. There are various commercially available platforms for such studies, but there remains no general consensus as to the optimal platform. There have been several previous platform comparison studies, but they have either described older technologies, used less-complex samples, or have not addressed the issue of the inherent biases in such comparisons. Here we describe a systematic comparison of data from four leading microarray technologies (the Affymetrix Genome-wide SNP 5.0 array, Agilent High-Density CGH Human 244A array, Illumina HumanCNV370-Duo DNA Analysis BeadChip, and the Nimblegen 385 K oligonucleotide array). We compare samples derived from primary breast tumours and their corresponding matched normals, well-established cancer cell lines, and HapMap individuals. By careful consideration and avoidance of potential sources of bias, we aim to provide a fair assessment of platform performance. Results By performing a theoretical assessment of the reproducibility, noise, and sensitivity of each platform, notable differences were revealed. Nimblegen exhibited between-replicate array variances an order of magnitude greater than the other three platforms, with Agilent slightly outperforming the others, and a comparison of self-self hybridizations revealed similar patterns. An assessment of the single probe power revealed that Agilent exhibits the highest sensitivity. Additionally, we performed an in-depth visual assessment of the ability of each platform to detect aberrations of varying sizes. As expected, all platforms were able to identify large aberrations in a robust manner. However, some focal amplifications and deletions were only detected in a subset of the platforms. Conclusion Although there are substantial differences in the design, density, and number of replicate probes, the comparison indicates a generally high level of concordance between platforms, despite differences in the reproducibility, noise, and sensitivity. In general, Agilent tended to be the best aCGH platform and Affymetrix, the superior SNP-CGH platform, but for specific decisions the results described herein provide a guide for platform selection and study design, and the dataset a resource for more tailored comparisons. PMID:19995423

Radiant coolers - Theory, flight histories, design comparisons and future applications

NASA Technical Reports Server (NTRS)

Donohoe, M. J.; Sherman, A.; Hickman, D. E.

1975-01-01

Radiant coolers have been developed for application to the cooling of infrared detectors aboard NASA earth observation systems and as part of the Defense Meteorological Satellite Program. The prime design constraints for these coolers are the location of the cooler aboard the satellite and the satellite orbit. Flight data from several coolers indicates that, in general, design temperatures are achieved. However, potential problems relative to the contamination of cold surfaces are also revealed by the data. A comparison among the various cooler designs and flight performances indicates design improvements that can minimize the contamination problem in the future.

Final report on the Seventh International Comparison of Absolute Gravimeters (ICAG 2005)

USGS Publications Warehouse

Jiang, Z.; Francis, O.; Vitushkin, L.; Palinkas, V.; Germak, A.; Becker, M.; D'Agostino, G.; Amalvict, M.; Bayer, R.; Bilker-Koivula, M.; Desogus, S.; Faller, J.; Falk, R.; Hinderer, J.; Gagnon, C.; Jakob, T.; Kalish, E.; Kostelecky, J.; Lee, C.; Liard, J.; Lokshyn, Y.; Luck, B.; Makinen, J.; Mizushima, S.; Le, Moigne N.; Origlia, C.; Pujol, E.R.; Richard, P.; Robertsson, L.; Ruess, D.; Schmerge, D.; Stus, Y.; Svitlov, S.; Thies, S.; Ullrich, C.; Van Camp, M.; Vitushkin, A.; Ji, W.; Wilmes, H.

2011-01-01

The Bureau International des Poids et Mesures (BIPM), S??vres, France, hosted the 7th International Comparison of Absolute Gravimeters (ICAG) and the associated Relative Gravity Campaign (RGC) from August to September 2005. ICAG 2005 was prepared and performed as a metrological pilot study, which aimed: To determine the gravity comparison reference values; To determine the offsets of the absolute gravimeters; and As a pilot study to accumulate experience for the CIPM Key Comparisons. This document presents a complete and extensive review of the technical protocol and data processing procedures. The 1st ICAG-RGC comparison was held at the BIPM in 1980-1981 and since then meetings have been organized every 4 years. In this paper, we present an overview of how the meeting was organized, the conditions of BIPM gravimetric sites, technical specifications, data processing strategy and an analysis of the final results. This 7th ICAG final report supersedes all previously published reports. Readings were obtained from participating instruments, 19 absolute gravimeters and 15 relative gravimeters. Precise levelling measurements were carried out and all measurements were performed on the BIPM micro-gravity network which was specifically designed for the comparison. ?? 2011 BIPM & IOP Publishing Ltd.

Design, Development and Analysis of Centrifugal Blower

NASA Astrophysics Data System (ADS)

Baloni, Beena Devendra; Channiwala, Salim Abbasbhai; Harsha, Sugnanam Naga Ramannath

2018-06-01

Centrifugal blowers are widely used turbomachines equipment in all kinds of modern and domestic life. Manufacturing of blowers seldom follow an optimum design solution for individual blower. Although centrifugal blowers are developed as highly efficient machines, design is still based on various empirical and semi empirical rules proposed by fan designers. There are different methodologies used to design the impeller and other components of blowers. The objective of present study is to study explicit design methodologies and tracing unified design to get better design point performance. This unified design methodology is based more on fundamental concepts and minimum assumptions. Parametric study is also carried out for the effect of design parameters on pressure ratio and their interdependency in the design. The code is developed based on a unified design using C programming. Numerical analysis is carried out to check the flow parameters inside the blower. Two blowers, one based on the present design and other on industrial design, are developed with a standard OEM blower manufacturing unit. A comparison of both designs is done based on experimental performance analysis as per IS standard. The results suggest better efficiency and more flow rate for the same pressure head in case of the present design compared with industrial one.

Performance metric comparison study for non-magnetic bi-stable energy harvesters

NASA Astrophysics Data System (ADS)

Udani, Janav P.; Wrigley, Cailin; Arrieta, Andres F.

2017-04-01

Energy harvesting employing non-linear systems offers considerable advantages over linear systems given the broadband resonant response which is favorable for applications involving diverse input vibrations. In this respect, the rich dynamics of bi-stable systems present a promising means for harvesting vibrational energy from ambient sources. Harvesters deriving their bi-stability from thermally induced stresses as opposed to magnetic forces are receiving significant attention as it reduces the need for ancillary components and allows for bio- compatible constructions. However, the design of these bi-stable harvesters still requires further optimization to completely exploit the dynamic behavior of these systems. This study presents a comparison of the harvesting capabilities of non-magnetic, bi-stable composite laminates under variations in the design parameters as evaluated utilizing established power metrics. Energy output characteristics of two bi-stable composite laminate plates with a piezoelectric patch bonded on the top surface are experimentally investigated for variations in the thickness ratio and inertial mass positions for multiple load conditions. A particular design configuration is found to perform better over the entire range of testing conditions which include single and multiple frequency excitation, thus indicating that design optimization over the geometry of the harvester yields robust performance. The experimental analysis further highlights the need for appropriate design guidelines for optimization and holistic performance metrics to account for the range of operational conditions.

Effects of a portion design plate on food group guideline adherence among hospital staff.

PubMed

de Korne, Dirk F; Malhotra, Rahul; Lim, Wai Yee; Ong, Christine; Sharma, Ashu; Tan, Tai Kiat; Tan, Thiam Chye; Ng, Kee Chong; Østbye, Truls

2017-01-01

Food group guideline adherence is vital to prevent obesity and diabetes. Various studies have demonstrated that environmental variables influence food intake behaviour. In the present study we examined the effect of a portion design plate with food group portion guidelines demarcated by coloured lines (ETE Plate™). A two-group quasi-experimental design was used to measure proportions of carbohydrate, vegetable and protein portions and user experience in a hospital staff lounge setting in Singapore. Lunch was served on the portion design plate before 12.15 hours. For comparison, a normal plate (without markings) was used after 12.15 hours. Changes in proportions of food groups from 2 months before the introduction of the design plate were analysed in a stratified sample at baseline (859 subjects, all on normal plates) to 1, 3 and 6 months after (in all 1016 subjects on the design plate, 968 subjects on the control plate). A total of 151 participants were asked about their experiences and opinions. Between-group comparisons were performed using t tests. Among those served on the portion design plate at 6 months after its introduction, the proportion of vegetables was 4·71 % ( P  < 0·001) higher and that of carbohydrates 2·83 % ( P  < 0·001) lower relative to the baseline. No significant change was found for proteins (-1·85 %). Over 6 months, we observed different change patterns between the different food group proportions. While participants were positive about the portion design plate, they did not think it would influence their personal behaviour. A portion design plate might stimulate food group guideline adherence among hospital staff and beyond.

Documenting helicopter operations from an energy standpoint

NASA Technical Reports Server (NTRS)

Davis, S. J.; Stepniewski, W. Z.

1974-01-01

Results are presented of a study of the relative and absolute energy consumption of helicopters, including limited comparisons with fixed-wing aircraft, and selected surface transportation vehicles. Additional comparisons were made to determine the level of reduction in energy consumption expected from the application of advanced technologies to the helicopter design and sizing process. It was found that improvements in helicopter consumption characteristics can be accomplished through the utilization of advanced technology to reduce drag, structures weight, and powerplant fuel consumption.

Planetary size comparisons: A photographic study

NASA Technical Reports Server (NTRS)

Meszaros, S. P.

1983-01-01

Over the past two decades NASA spacecraft missions obtained photographs permitting accurate size measurements of the planets and moons, and their surface features. Planetary global views are displayed at the same scale, in each picture to allow visual size comparisons. Additionally, special geographical features on some of the planets are compared with selected Earth areas, again at the same scale. Artist renderings and estimated sizes are used for worlds not yet reached by spacecraft. Included with each picture is number designation for use in ordering copies of the photos.

Development of a mobile toolmark characterization/comparison system [Development of a mobile, automated toolmark characterization/comparison system

DOE PAGES

Chumbley, Scott; Zhang, Song; Morris, Max; ...

2016-11-16

Since the development of the striagraph, various attempts have been made to enhance forensic investigation through the use of measuring and imaging equipment. This study describes the development of a prototype system employing an easy-to-use software interface designed to provide forensic examiners with the ability to measure topography of a toolmarked surface and then conduct various comparisons using a statistical algorithm. Acquisition of the data is carried out using a portable 3D optical profilometer, and comparison of the resulting data files is made using software named “MANTIS” (Mark and Tool Inspection Suite). The system has been tested on laboratory-produced markingsmore » that include fully striated marks (e.g., screwdriver markings), quasistriated markings produced by shear-cut pliers, impression marks left by chisels, rifling marks on bullets, and cut marks produced by knives. Using the system, an examiner has the potential to (i) visually compare two toolmarked surfaces in a manner similar to a comparison microscope and (ii) use the quantitative information embedded within the acquired data to obtain an objective statistical comparison of the data files. Finally, this study shows that, based on the results from laboratory samples, the system has great potential for aiding examiners in conducting comparisons of toolmarks.« less

Development of a mobile toolmark characterization/comparison system [Development of a mobile, automated toolmark characterization/comparison system

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

Chumbley, Scott; Zhang, Song; Morris, Max

Since the development of the striagraph, various attempts have been made to enhance forensic investigation through the use of measuring and imaging equipment. This study describes the development of a prototype system employing an easy-to-use software interface designed to provide forensic examiners with the ability to measure topography of a toolmarked surface and then conduct various comparisons using a statistical algorithm. Acquisition of the data is carried out using a portable 3D optical profilometer, and comparison of the resulting data files is made using software named “MANTIS” (Mark and Tool Inspection Suite). The system has been tested on laboratory-produced markingsmore » that include fully striated marks (e.g., screwdriver markings), quasistriated markings produced by shear-cut pliers, impression marks left by chisels, rifling marks on bullets, and cut marks produced by knives. Using the system, an examiner has the potential to (i) visually compare two toolmarked surfaces in a manner similar to a comparison microscope and (ii) use the quantitative information embedded within the acquired data to obtain an objective statistical comparison of the data files. Finally, this study shows that, based on the results from laboratory samples, the system has great potential for aiding examiners in conducting comparisons of toolmarks.« less

Elementary teachers' mental models of engineering design processes: A comparison of two communities of practice

NASA Astrophysics Data System (ADS)

McMahon, Ann P.

Educating K-12 students in the processes of design engineering is gaining popularity in public schools. Several states have adopted standards for engineering design despite the fact that no common agreement exists on what should be included in the K-12 engineering design process. Furthermore, little pre-service and in-service professional development exists that will prepare teachers to teach a design process that is fundamentally different from the science teaching process found in typical public schools. This study provides a glimpse into what teachers think happens in engineering design compared to articulated best practices in engineering design. Wenger's communities of practice work and van Dijk's multidisciplinary theory of mental models provide the theoretical bases for comparing the mental models of two groups of elementary teachers (one group that teaches engineering and one that does not) to the mental models of design engineers (including this engineer/researcher/educator and professionals described elsewhere). The elementary school teachers and this engineer/researcher/educator observed the design engineering process enacted by professionals, then answered questions designed to elicit their mental models of the process they saw in terms of how they would teach it to elementary students. The key finding is this: Both groups of teachers embedded the cognitive steps of the design process into the matrix of the social and emotional roles and skills of students. Conversely, the engineers embedded the social and emotional aspects of the design process into the matrix of the cognitive steps of the design process. In other words, teachers' mental models show that they perceive that students' social and emotional communicative roles and skills in the classroom drive their cognitive understandings of the engineering process, while the mental models of this engineer/researcher/educator and the engineers in the video show that we perceive that cognitive understandings of the engineering process drive the social and emotional roles and skills used in that process. This comparison of mental models with the process that professional designers use defines a problem space for future studies that investigate how to incorporate engineering practices into elementary classrooms. Recommendations for engineering curriculum development and teacher professional development based on this study are presented.

Planetary/DOD entry technology flight experiments. Volume 2: Planetary entry flight experiments

NASA Technical Reports Server (NTRS)

Christensen, H. E.; Krieger, R. J.; Mcneilly, W. R.; Vetter, H. C.

1976-01-01

The technical feasibility of launching a high speed, earth entry vehicle from the space shuttle to advance technology for the exploration of the outer planets' atmospheres was established. Disciplines of thermodynamics, orbital mechanics, aerodynamics propulsion, structures, design, electronics and system integration focused on the goal of producing outer planet environments on a probe shaped vehicle during an earth entry. Major aspects of analysis and vehicle design studied include: planetary environments, earth entry environment capability, mission maneuvers, capabilities of shuttle upper stages, a comparison of earth entry planetary environments, experiment design and vehicle design.

Strategies and arguments of ergonomic design for sustainability.

PubMed

Marano, Antonio; Di Bucchianico, Giuseppe; Rossi, Emilio

2012-01-01

Referring to the discussion recently promoted by the Sub-Technical Committee n°4 "Ergonomics and design for sustainability", in this paper will be shown the early results of a theoretical and methodological study on Ergonomic design for sustainability. In particular, the research is based on the comparison between the common thematic structure characterizing Ergonomics, with the principles of Sustainable Development and with criteria adopted from other disciplines already oriented toward Sustainability. The paper identifies an early logical-interpretative model and describes possible and relevant Strategies of Ergonomic design for sustainability, which are connected in a series of specific Sustainable Arguments.

Use of constrained optimization in the conceptual design of a medium-range subsonic transport

NASA Technical Reports Server (NTRS)

Sliwa, S. M.

1980-01-01

Constrained parameter optimization was used to perform the optimal conceptual design of a medium range transport configuration. The impact of choosing a given performance index was studied, and the required income for a 15 percent return on investment was proposed as a figure of merit. A number of design constants and constraint functions were systematically varied to document the sensitivities of the optimal design to a variety of economic and technological assumptions. A comparison was made for each of the parameter variations between the baseline configuration and the optimally redesigned configuration.

A Comparison of Structurally Connected and Multiple Spacecraft Interferometers

NASA Technical Reports Server (NTRS)

Surka, Derek M.; Crawley, Edward F.

1996-01-01

Structurally connected and multiple spacecraft interferometers are compared in an attempt to establish the maximum baseline (referred to as the "cross-over baseline") for which it is preferable to operate a single-structure interferometer in space rather than an interferometer composed of numerous, smaller spacecraft. This comparison is made using the total launched mass of each configuration as the comparison metric. A framework of study within which structurally connected and multiple spacecraft interferometers can be compared is presented in block diagram form. This methodology is then applied to twenty-two different combinations of trade space parameters to investigate the effects of different orbits, orientations, truss materials, propellants, attitude control actuators, onboard disturbance sources, and performance requirements on the cross-over baseline. Rotating interferometers and the potential advantages of adding active structural control to the connected truss of the structurally connected interferometer are also examined. The minimum mass design of the structurally connected interferometer that meets all performance-requirements and satisfies all imposed constraints is determined as a function of baseline. This minimum mass design is then compared to the design of the multiple spacecraft interferometer. It is discovered that the design of the minimum mass structurally connected interferometer that meets all performance requirements and constraints in solar orbit is limited by the minimum allowable aspect ratio, areal density, and gage of the struts. In the formulation of the problem used in this study, there is no advantage to adding active structural control to the truss for interferometers in solar orbit. The cross-over baseline for missions of practical duration (ranging from one week to thirty years) in solar orbit is approximately 400 m for non-rotating interferometers and 650 m for rotating interferometers.

Enhancing Exposure Therapy for PTSD: Virtual Reality and Imaginal Exposure with a Cognitive Enhancer

DTIC Science & Technology

2016-10-01

the author(s) and should not be construed as an official Department of the Army position, policy or decision unless so designated by other...x 2 design will allow several important comparisons to be made: a direct comparison of the efficacy of virtual reality versus imaginal exposure...College; Cypress College; Otis College of Art and Design ; Golden West College; Los Angeles Southwestern College; Art Institute of California; Antioch

Capability Extension to the Turbine Off-Design Computer Program AXOD With Applications to the Highly Loaded Fan-Drive Turbines

NASA Technical Reports Server (NTRS)

Chen, Shu-cheng S.

2011-01-01

The axial flow turbine off-design computer program AXOD has been upgraded to include the outlet guide vane (OGV) into its acceptable turbine configurations. The mathematical bases and the techniques used for the code implementation are described and discussed in lengths in this paper. This extended capability is verified and validated with two cases of highly loaded fan-drive turbines, designed and tested in the V/STOL Program of NASA. The first case is a 4 1/2-stage turbine with an average stage loading factor of 4.66, designed by Pratt & Whitney Aircraft. The second case is a 3 1/2-stage turbine with an average loading factor of 4.0, designed in-house by the NASA Lewis Research Center (now the NASA Glenn Research Center). Both cases were experimentally tested in the turbine facility located at the Glenn Research Center. The processes conducted in these studies are described in detail in this paper, and the results in comparison with the experimental data are presented and discussed. The comparisons between the AXOD results and the experimental data are in excellent agreement.

Biomechanical comparison of straight and helical compression plates for fixation of transverse and oblique bone fractures: Modeling and experiments.

PubMed

Sezek, Sinan; Aksakal, Bunyamin; Gürger, Murat; Malkoc, Melih; Say, Y

2016-08-12

Total deformation and stability of straight and helical compression plates were studied by means of the finite element method (FEM) and in vitro biomechanical experiments. Fixations of transverse (TF) and oblique (45°) bone (OF) fractures have been analyzed on sheep tibias by designing the straight compression (SP) and Helical Compression Plate (HP) models. The effects of axial compression, bending and torsion loads on both plating systems were analyzed in terms of total displacements. Numerical models and experimental models suggested that under compression loadings, bone fracture gap closures for both fracture types were found to be in the favor of helical plate designs. The helical plate (HP) fixations provided maximum torsional resistance compared to the (SP) fixations. The fracture gap closure and stability of helical plate fixation for transverse fractures was determined to be higher than that found for the oblique fractures. The comparison of average compression stress, bending and torsion moments showed that the FEM and experimental results are in good agreement and such designs are likely to have a positive impact in future bone fracture fixation designs.

[Clinical research. XIII. Research design contribution in the structured revision of an article].

PubMed

Talavera, Juan O; Rivas-Ruiz, Rodolfo

2013-01-01

The quality of information obtained in accordance to research design is integrated to the revision structured in relation to the causality model, used in the article "Reduction in the Incidence of Nosocomial Pneumonia Poststroke by Using the 'Turn-mob' Program", which corresponds to a clinical trial design. Points to identify and analyze are ethical issues in order to safeguard the security and respect for patients, randomization that seek to create basal homogeneous groups, subjects with the same probability of receiving any of the maneuvers in comparison, with the same pre maneuver probability of adherence, and which facilitate the blinding of outcome measurement and the distribution between groups of subjects with the same probability of leaving the study for reasons beyond the maneuvers. Other aspects are the relativity of comparison, the blinding of the maneuver, the parallel application of comparative maneuver, early stopping, and analysis according to the degree of adherence. The analysis in accordance with the design is complementary, since it is done based on the architectural model of causality, and the statistical and clinical relevance consideration.

Analysis of Nonequivalent Assessments across Different Linguistic Groups Using a Mixed Methods Approach: Understanding the Causes of Differential Item Functioning by Cognitive Interviewing

ERIC Educational Resources Information Center

Benítez, Isabel; Padilla, José-Luis

2014-01-01

Differential item functioning (DIF) can undermine the validity of cross-lingual comparisons. While a lot of efficient statistics for detecting DIF are available, few general findings have been found to explain DIF results. The objective of the article was to study DIF sources by using a mixed method design. The design involves a quantitative phase…

Preliminary Study of Image Reconstruction Algorithm on a Digital Signal Processor

DTIC Science & Technology

2014-03-01

5.2 Comparison of CPU-GPU, CPU-FPGA, and CPU-DSP Designs The work for implementing VHDL description of the back-projection algorithm on a physical...FPGA was not complete. Hence, the DSP implementation results are compared with the simulated results for the VHDL design. Simulating VHDL provides an...rather than at the software level. Depending on an application’s characteristics, FPGA implementations can provide a significant performance

Dual-polarization airborne lidar for freshwater fisheries management and research

NASA Astrophysics Data System (ADS)

Roddewig, Michael R.; Pust, Nathan J.; Churnside, James H.; Shaw, Joseph A.

2017-03-01

The design of a compact, dual-polarization, nonscanning lidar system intended to fly in a small, single-engine aircraft for airborne study of freshwater marine ecosystems and mapping of fish schools in mountain lakes is discussed. Design trade-offs are presented with special attention paid to selecting the field of view and telescope aperture diameter. Example results and a comparison with a similar existing lidar system are presented.

The Sampling Design of the China Family Panel Studies (CFPS)

PubMed Central

Xie, Yu; Lu, Ping

2018-01-01

The China Family Panel Studies (CFPS) is an on-going, nearly nationwide, comprehensive, longitudinal social survey that is intended to serve research needs on a large variety of social phenomena in contemporary China. In this paper, we describe the sampling design of the CFPS sample for its 2010 baseline survey and methods for constructing weights to adjust for sampling design and survey nonresponses. Specifically, the CFPS used a multi-stage probability strategy to reduce operation costs and implicit stratification to increase efficiency. Respondents were oversampled in five provinces or administrative equivalents for regional comparisons. We provide operation details for both sampling and weights construction. PMID:29854418

The conceptual design of a hybrid life support system based on the evaluation and comparison of terrestrial testbeds

NASA Astrophysics Data System (ADS)

Czupalla, M.; Horneck, G.; Blome, H. J.

This report summarizes a trade study of different options of a bioregenerative Life Support System (LSS) and a subsequent conceptual design of a hybrid LSS. The evaluation was based mainly on the terrestrial testbed projects MELISSA (ESA) and BIOS (Russia). In addition, some methods suggested by the Advanced Life Support Project (NASA) were considered. Computer models, including mass flows were established for each of the systems with the goal of closing system loops to the extent possible. In order to cope with the differences in the supported crew size and provided nutrition, all systems were scaled for supporting a crew of six for a 780 day Mars mission (180 days transport to Mars; 600 days surface period) as given in the NASA Design Reference Mission Scenario [Hoffman, S.J., Kaplan, D.L. Human exploration of Mars: the Reference Mission of the NASA Mars Exploratory Study, 1997]. All models were scaled to provide the same daily allowances, as of calories, to the crew. Equivalent System Mass (ESM) analysis was used to compare the investigated system models against each other. Following the comparison of the terrestrial systems, the system specific subsystem options for Food Supply, Solid Waste Processing, Water Management and Atmosphere Revitalization were evaluated in a separate trade study. The best subsystem technologies from the trade study were integrated into an overall design solution based on mass flow relationships. The optimized LSS is mainly a bioregenerative system, complemented by a few physico-chemical elements, with a total ESM of 18,088 kg, which is about 4 times higher than that of a pure physico-chemical LSS, as designed in an earlier study.

The conceptual design of a hybrid life support system based on the evaluation and comparison of terrestrial testbeds.

PubMed

Czupalla, M; Horneck, G; Blome, H J

2005-01-01

This report summarizes a trade study of different options of a bioregenerative Life Support System (LSS) and a subsequent conceptual design of a hybrid LSS. The evaluation was based mainly on the terrestrial testbed projects MELISSA (ESA) and BIOS (Russia). In addition, some methods suggested by the Advanced Life Support Project (NASA) were considered. Computer models, including mass flows were established for each of the systems with the goal of closing system loops to the extent possible. In order to cope with the differences in the supported crew size and provided nutrition, all systems were scaled for supporting a crew of six for a 780 day Mars mission (180 days transport to Mars; 600 days surface period) as given in the NASA Design Reference Mission Scenario [Hoffman, S.J., Kaplan, D.L. Human exploration of Mars: the Reference Mission of the NASA Mars Exploratory Study, 1997]. All models were scaled to provide the same daily allowances, as of calories, to the crew. Equivalent System Mass (ESM) analysis was used to compare the investigated system models against each other. Following the comparison of the terrestrial systems, the system specific subsystem options for Food Supply, Solid Waste Processing, Water Management and Atmosphere Revitalization were evaluated in a separate trade study. The best subsystem technologies from the trade study were integrated into an overall design solution based on mass flow relationships. The optimized LSS is mainly a bioregenerative system, complemented by a few physico-chemical elements, with a total ESM of 18,088 kg, which is about 4 times higher than that of a pure physico-chemical LSS, as designed in an earlier study. c2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

Lecture and Workshop Modes Comparison on Rangeland Developments: The Case of Iran

ERIC Educational Resources Information Center

Shahvali, M.; Poursaeed, A.; Sharifzadeh, M.

2009-01-01

This study investigated the effects of workshop and lecture methods on pastoralists' learning in Ilam Province, west of Iran. A quasi-experimental research method and non-equivalent control group design was used. Sixty pastoralists participated in this study. An open-ended questionnaire was used as the instrument of the study and found to have…

Classroom-Based Narrative and Vocabulary Instruction: Results of an Early-Stage, Nonrandomized Comparison Study

ERIC Educational Resources Information Center

Gillam, Sandra Laing; Olszewski, Abbie; Fargo, Jamison; Gillam, Ronald B.

2014-01-01

Purpose: This nonrandomized feasibility study was designed to provide a preliminary assessment of the impact of a narrative and vocabulary instruction program provided by a speech-language pathologist (SLP) in a regular classroom setting. Method: Forty-three children attending 2 first-grade classrooms participated in the study. Children in each…

An Exploratory Comparison of Traditional Classroom Instruction and Anchored Instruction with Secondary School Students: Turkish Experience

ERIC Educational Resources Information Center

Elcin, Melih; Sezer, Baris

2014-01-01

The purpose of this study was to investigate the impact of anchored instruction on the students in secondary school math studies classrooms. This study adopted a quasi-experimental design. This research involved both quantitative and qualitative methods to investigate the effects of anchored instruction on students' academical achievement,…

The Case Study Method: Guidelines, Practices, and Applications for Vocational Education. Research and Development Series No. 189.

ERIC Educational Resources Information Center

Spirer, Janet E.

In comparison with traditional experimental design, which is concerned with what happened, a case study approach is more appropriate for answering the question of why or how something happened. As an alternative complementary-vocational-education-evaluation approach, the case study attempts to describe and analyze some program in comprehensive…

An Analysis of Female Lecturers' Participation in Civil Engineering Research and Development Activities at One Polytechnic in Zimbabwe

ERIC Educational Resources Information Center

Chikuvadze, Pinias; Matswetu, Vimbai Sharon; Mugijima, Samuel

2015-01-01

This study sought to explore female lecturers' participation in civil engineering research and development activities at one polytechnic in Zimbabwe. Case study design was chosen for this study to make predictions, narration of events, comparisons and drawing of conclusions. The female lecturers were purposively sampled to participate in the…

Ethnographic Depiction of a Multiethnic School: A Comparison to Desegregated Settings.

ERIC Educational Resources Information Center

Semons, Maryann

This report compares the findings of a recent ethnographic study of a multiethnic urban high school to some of the highlights of a series of ten-year-old ethnographic studies on court-ordered desegregated school settings. The study of the multiethnic urban school employed an ethnographic design whereby a participant-observer interviewed students…

Assessing the Teaching Efficacy Beliefs of Teacher Trainees: A Comparison of Two Institutions of Higher Learning in South Africa

ERIC Educational Resources Information Center

Matoti, Sheila N.; Junqueira, Karen E.; Odora, Ronald J.

2013-01-01

This study assessed the teaching efficacy beliefs of third-year teacher education students from two different institutions, in three categories: student engagement, instructional strategies and classroom management. The study used a descriptive survey design. The target population for the study was all third-year students enrolled in five…

Study Abroad during College: Comparison between China and the United States

ERIC Educational Resources Information Center

Li, Jing; Guo, Fei; You, You

2017-01-01

Study abroad can be a life-changing experience, but evidence of its effectiveness is mixed. We examine the experience of studying abroad at colleges in the US and China, which are the largest receiving and sending countries of international students respectively. Using data from two comparable national surveys that follow the same design, we…

Design of 3 GeV booster ring lattice

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

Etisken, O., E-mail: ozgur.etisken@cern.ch; Ciftci, A. K., E-mail: abbas.kenan.ciftci@cern.ch

2016-03-25

The aim of this study is to design of a 3 GeV booster ring for the 3 GeV storage ring. Electrons are needed to be accelerated to 3.0 GeV from 0.15 GeV energy. In this frame, we studied on two options for booster ring; a compact booster and the booster that shares the same tunnel with the storage ring. The lattice type has been chosen FODO for both options, lattice parameters are calculated, sextupole magnets are used to decrease dynamic aperture problem and dynamic aperture calculations are also made with considering of the necessary conditions. After designing and calculating ofmore » the parameters, these designs have been compared with each other. In addition to this comparison, these booster design parameters have been compared with some world centers design parameters and the reliability of the booster design is seen. Beam optics, OPA and Elegant simulation programs have been used in the study calculations.« less

Exploring Robust Methods for Evaluating Treatment and Comparison Groups in Chronic Care Management Programs

PubMed Central

Hamar, Brent; Bradley, Chastity; Gandy, William M.; Harrison, Patricia L.; Sidney, James A.; Coberley, Carter R.; Rula, Elizabeth Y.; Pope, James E.

2013-01-01

Abstract Evaluation of chronic care management (CCM) programs is necessary to determine the behavioral, clinical, and financial value of the programs. Financial outcomes of members who are exposed to interventions (treatment group) typically are compared to those not exposed (comparison group) in a quasi-experimental study design. However, because member assignment is not randomized, outcomes reported from these designs may be biased or inefficient if study groups are not comparable or balanced prior to analysis. Two matching techniques used to achieve balanced groups are Propensity Score Matching (PSM) and Coarsened Exact Matching (CEM). Unlike PSM, CEM has been shown to yield estimates of causal (program) effects that are lowest in variance and bias for any given sample size. The objective of this case study was to provide a comprehensive comparison of these 2 matching methods within an evaluation of a CCM program administered to a large health plan during a 2-year time period. Descriptive and statistical methods were used to assess the level of balance between comparison and treatment members pre matching. Compared with PSM, CEM retained more members, achieved better balance between matched members, and resulted in a statistically insignificant Wald test statistic for group aggregation. In terms of program performance, the results showed an overall higher medical cost savings among treatment members matched using CEM compared with those matched using PSM (-$25.57 versus -$19.78, respectively). Collectively, the results suggest CEM is a viable alternative, if not the most appropriate matching method, to apply when evaluating CCM program performance. (Population Health Management 2013;16:35–45) PMID:22788834

Exploring robust methods for evaluating treatment and comparison groups in chronic care management programs.

PubMed

Wells, Aaron R; Hamar, Brent; Bradley, Chastity; Gandy, William M; Harrison, Patricia L; Sidney, James A; Coberley, Carter R; Rula, Elizabeth Y; Pope, James E

2013-02-01

Evaluation of chronic care management (CCM) programs is necessary to determine the behavioral, clinical, and financial value of the programs. Financial outcomes of members who are exposed to interventions (treatment group) typically are compared to those not exposed (comparison group) in a quasi-experimental study design. However, because member assignment is not randomized, outcomes reported from these designs may be biased or inefficient if study groups are not comparable or balanced prior to analysis. Two matching techniques used to achieve balanced groups are Propensity Score Matching (PSM) and Coarsened Exact Matching (CEM). Unlike PSM, CEM has been shown to yield estimates of causal (program) effects that are lowest in variance and bias for any given sample size. The objective of this case study was to provide a comprehensive comparison of these 2 matching methods within an evaluation of a CCM program administered to a large health plan during a 2-year time period. Descriptive and statistical methods were used to assess the level of balance between comparison and treatment members pre matching. Compared with PSM, CEM retained more members, achieved better balance between matched members, and resulted in a statistically insignificant Wald test statistic for group aggregation. In terms of program performance, the results showed an overall higher medical cost savings among treatment members matched using CEM compared with those matched using PSM (-$25.57 versus -$19.78, respectively). Collectively, the results suggest CEM is a viable alternative, if not the most appropriate matching method, to apply when evaluating CCM program performance.

The Motor Core of Speech: A Comparison of Serial Organization Patterns in Infants and Languages.

ERIC Educational Resources Information Center

MacNeilage, Peter F.; Davis, Barbara L.; Kinney, Ashlynn; Matyear, Christine L.

2000-01-01

Presents evidence for four major design features of serial organization of speech arising from comparison of babbling and early speech with patterns in ten languages. Maintains that no explanation for the design features is available from Universal Grammar; except for intercyclical consonant repetition development, perceptual-motor learning seems…

Comparison of JSFR design with EDF requirements for future SFR

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

Uematsu, M. M.; Prele, G.; Mariteau, P.

2012-07-01

A comparison of Japan sodium-cooled fast reactor (JSFR) design with future French SFR concept has been done based on the requirement of EDF, the investor-operator of future French SFR, and the French safety baseline, under the framework of EDF-JAEA bilateral agreement of research and development cooperation on future SFR. (authors)

Design and Comparison of Cascaded H-Bridge, Modular Multilevel Converter, and 5-L Active Neutral Point Clamped Topologies for Motor Drive Applications

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

Marzoughi, Alinaghi; Burgos, Rolando; Boroyevich, Dushan

This paper presents the design procedure and comparison of converters currently used in medium-voltage high-power motor drive applications. For this purpose, the cascaded H-bridge (CHB), modular multilevel converter (MMC), and five-level active neutral point clamped (5-L ANPC) topologies are targeted. The design is performed using 1.7-kV insulated gate bipolar transistors (IGBTs) for CHB and MMC converters, and utilizing 3.3- and 4.5-kV IGBTs for 5-L ANPC topology as normally done in industry. The comparison is done between the designed converter topologies at three different voltage levels (4.16, 6.9, and 13.8 kV, with only the first two voltage levels in case ofmore » the 5-L ANPC) and two different power levels (3 and 5 MVA), in order to elucidate the dependence of different parameters on voltage and power rating. Finally, the comparison is done from several points of view such as efficiency, capacitive energy storage, semiconductor utilization, parts count (for measure of reliability), and power density.« less

The Role of Hospital Design in Reducing Anxiety for Pediatric Patients.

PubMed

Cartland, Jenifer; Ruch-Ross, Holly S; Carr, Lauren; Hall, Audrey; Olsen, Richard; Rosendale, Ellen; Ruohonen, Susan

2018-01-01

To study the impact of hospital design on patient and family experiences during and after hospitalization. Hospitalization can be psychologically traumatic for children. Few research studies have studied the role of the design of the hospital environment in mitigating that traumatic experience. The study employs a two-group posttest and follow-up design to compare the impact of hospitalization on child anxiety and parent stress. It compares the experiences of children (ages 3-17) hospitalized at a new facility designed to support child-centered care and with family-friendly features with an older facility that did not have these features. The new facility was a replacement of the old one, so that many challenges to comparison are addressed. Controlling for the facts of hospitalization, patient demographics, and the child's typical anxiety level, children in the new facility experienced less anxiety than in the old facility. The study does not provide evidence that the hospital design reduced the psychological sequelae of hospitalization. Parents and children found different features of the hospital to be restorative. The study supports the use of Ulrich's theory of supportive design to children's healthcare environments, though what is experienced as supportive design will vary by the developmental stage of the child.

Advanced Transportation System Studies. Technical Area 3: Alternate Propulsion Subsystem Concepts. Volume 1; Executive Summary

NASA Technical Reports Server (NTRS)

Levack, Daniel J. H.

2000-01-01

The Alternate Propulsion Subsystem Concepts contract had seven tasks defined that are reported under this contract deliverable. The tasks were: FAA Restart Study, J-2S Restart Study, Propulsion Database Development. SSME Upper Stage Use. CERs for Liquid Propellant Rocket Engines. Advanced Low Cost Engines, and Tripropellant Comparison Study. The two restart studies, F-1A and J-2S, generated program plans for restarting production of each engine. Special emphasis was placed on determining changes to individual parts due to obsolete materials, changes in OSHA and environmental concerns, new processes available, and any configuration changes to the engines. The Propulsion Database Development task developed a database structure and format which is easy to use and modify while also being comprehensive in the level of detail available. The database structure included extensive engine information and allows for parametric data generation for conceptual engine concepts. The SSME Upper Stage Use task examined the changes needed or desirable to use the SSME as an upper stage engine both in a second stage and in a translunar injection stage. The CERs for Liquid Engines task developed qualitative parametric cost estimating relationships at the engine and major subassembly level for estimating development and production costs of chemical propulsion liquid rocket engines. The Advanced Low Cost Engines task examined propulsion systems for SSTO applications including engine concept definition, mission analysis. trade studies. operating point selection, turbomachinery alternatives, life cycle cost, weight definition. and point design conceptual drawings and component design. The task concentrated on bipropellant engines, but also examined tripropellant engines. The Tripropellant Comparison Study task provided an unambiguous comparison among various tripropellant implementation approaches and cycle choices, and then compared them to similarly designed bipropellant engines in the SSTO mission This volume overviews each of the tasks giving its objectives, main results. and conclusions. More detailed Final Task Reports are available on each individual task.

EDIN design study alternate space shuttle booster replacement concepts. Volume 2: Design simulation results

NASA Technical Reports Server (NTRS)

Demakes, P. T.; Hirsch, G. N.; Stewart, W. A.; Glatt, C. R.

1976-01-01

Historical weight estimating relationships were developed for the liquid rocket booster (LRB) using Saturn technology, and modified as required to support the EDIN05 study. Mission performance was computed using February 1975 shuttle configuration groundrules to allow reasonable comparison of the existing shuttle with the EDIN05 designs. The launch trajectory was constrained to pass through both the RTLS/AOA and main engine cut-off points. Performance analysis was based on a point design trajectory model which optimized initial tilt rate and exo-atmospheric pitch profile. A gravity turn was employed during the boost phase in place of the shuttle angle-of-attack profile. Engine throttling add/or shutdown was used to constrain dynamic pressure and/or longitudinal acceleration where necessary.

A design procedure for a tension-wire stiffened truss-column

NASA Technical Reports Server (NTRS)

Greene, W. H.

1980-01-01

A deployable, tension wire stiffened, truss column configuration was considered for space structure applications. An analytical procedure, developed for design of the truss column and exercised in numerical studies, was based on equivalent beam stiffness coefficients in the classical analysis for an initially imperfect beam column. Failure constraints were formulated to be used in a combined weight/strength and nonlinear mathematical programming automated design procedure to determine the minimum mass column for a particular combination of design load and length. Numerical studies gave the mass characteristics of the truss column for broad ranges of load and length. Comparisons of the truss column with a baseline tubular column used a special structural efficiency parameter for this class of columns.

Physics and engineering studies on the MITICA accelerator: comparison among possible design solutions

NASA Astrophysics Data System (ADS)

Agostinetti, P.; Antoni, V.; Cavenago, M.; Chitarin, G.; Pilan, N.; Marcuzzi, D.; Serianni, G.; Veltri, P.

2011-09-01

Consorzio RFX in Padova is currently using a comprehensive set of numerical and analytical codes, for the physics and engineering design of the SPIDER (Source for Production of Ion of Deuterium Extracted from RF plasma) and MITICA (Megavolt ITER Injector Concept Advancement) experiments, planned to be built at Consorzio RFX. This paper presents a set of studies on different possible geometries for the MITICA accelerator, with the objective to compare different design concepts and choose the most suitable one (or ones) to be further developed and possibly adopted in the experiment. Different design solutions have been discussed and compared, taking into account their advantages and drawbacks by both the physics and engineering points of view.

Daylight Design for Urban Residential Planning in Poland in Regulations and in A Practice. A Comparison Study of Daylight Conditions Observed in the Four Neighbouring Residential Areas

NASA Astrophysics Data System (ADS)

Sokol, Natalia; Martyniuk-Peczek, Justyna

2017-10-01

This paper reports on the partial results of the research aiming to illustrate how an integration of daylight design into an architectural planning process can help designers to create the residential buildings in respect to the environmental issues, solar and illuminance gains, as well as, the residents’ needs and comfort. It describes how changing daylight recommendations affected the design of the block of flats regarding their orientation, the spacing, the forms, and the size of the windows in the four urban residential areas. The results of this study help to determine more precise characterization of daylight indicators useful in architectural planning.

Numerical studies of the thermal design sensitivity calculation for a reaction-diffusion system with discontinuous derivatives

NASA Technical Reports Server (NTRS)

Hou, Jean W.; Sheen, Jeen S.

1987-01-01

The aim of this study is to find a reliable numerical algorithm to calculate thermal design sensitivities of a transient problem with discontinuous derivatives. The thermal system of interest is a transient heat conduction problem related to the curing process of a composite laminate. A logical function which can smoothly approximate the discontinuity is introduced to modify the system equation. Two commonly used methods, the adjoint variable method and the direct differentiation method, are then applied to find the design derivatives of the modified system. The comparisons of numerical results obtained by these two methods demonstrate that the direct differentiation method is a better choice to be used in calculating thermal design sensitivity.

Numerical and experimental study of the performance effects of varying vaneless space in high-speed micro turbine stators

NASA Astrophysics Data System (ADS)

Ke, Changlei; Xiong, Lianyou; Peng, Nan; Dong, Bin; Li, Kongrong; Li, Jing; Liu, Liqiang

2017-12-01

In order to make direct performance comparisons of varying the vaneless space in high-speed micro turbomachinery, an extensive experimental and numerical program have been carried out on a 22 mm leading-edge diameter mixed and inward flow radial turbine using a variety of stator designs. The stator was designed using commercial design software, having 9 vanes and the radial clearance (vaneless space) between stator and rotor was 0.5 mm single side, that means the ratio of the stator trailing edge radius to the rotor leading edge radius Rte/rle is 1.0455. Two additional stators (Rte/rle is 1.0182 and 1.0727) were also designed and manufactured. According to the design condition, just like pressure at stator inlet or mass flow rate for all passages, a series of CFD simulations were carried out in order to guide design iterations towards achieving a matched flow capacity for each stator. In this way the variations in the measured stage efficiency could be attributed to the stator passages only, thus allowing direct comparisons to be made. The losses for different radial clearances have been quantified and the variations in the measured and computed efficiency were used to recommend optimum values of Rte/rle.

An analysis of adaptive design variations on the sequential parallel comparison design for clinical trials.

PubMed

Mi, Michael Y; Betensky, Rebecca A

2013-04-01

Currently, a growing placebo response rate has been observed in clinical trials for antidepressant drugs, a phenomenon that has made it increasingly difficult to demonstrate efficacy. The sequential parallel comparison design (SPCD) is a clinical trial design that was proposed to address this issue. The SPCD theoretically has the potential to reduce the sample-size requirement for a clinical trial and to simultaneously enrich the study population to be less responsive to the placebo. Because the basic SPCD already reduces the placebo response by removing placebo responders between the first and second phases of a trial, the purpose of this study was to examine whether we can further improve the efficiency of the basic SPCD and whether we can do so when the projected underlying drug and placebo response rates differ considerably from the actual ones. Three adaptive designs that used interim analyses to readjust the length of study duration for individual patients were tested to reduce the sample-size requirement or increase the statistical power of the SPCD. Various simulations of clinical trials using the SPCD with interim analyses were conducted to test these designs through calculations of empirical power. From the simulations, we found that the adaptive designs can recover unnecessary resources spent in the traditional SPCD trial format with overestimated initial sample sizes and provide moderate gains in power. Under the first design, results showed up to a 25% reduction in person-days, with most power losses below 5%. In the second design, results showed up to a 8% reduction in person-days with negligible loss of power. In the third design using sample-size re-estimation, up to 25% power was recovered from underestimated sample-size scenarios. Given the numerous possible test parameters that could have been chosen for the simulations, the study's results are limited to situations described by the parameters that were used and may not generalize to all possible scenarios. Furthermore, dropout of patients is not considered in this study. It is possible to make an already complex design such as the SPCD adaptive, and thus more efficient, potentially overcoming the problem of placebo response at lower cost. Ultimately, such a design may expedite the approval of future effective treatments.

Optimal Solution for an Engineering Applications Using Modified Artificial Immune System

NASA Astrophysics Data System (ADS)

Padmanabhan, S.; Chandrasekaran, M.; Ganesan, S.; patan, Mahamed Naveed Khan; Navakanth, Polina

2017-03-01

An Engineering optimization leads a essential role in several engineering application areas like process design, product design, re-engineering and new product development, etc. In engineering, an awfully best answer is achieved by comparison to some completely different solutions by utilization previous downside information. An optimization algorithms provide systematic associate degreed economical ways that within which of constructing and comparison new design solutions so on understand at best vogue, thus on best solution efficiency and acquire the foremost wonderful design impact. In this paper, a new evolutionary based Modified Artificial Immune System (MAIS) algorithm used to optimize an engineering application of gear drive design. The results are compared with existing design.

Enhancing the educational achievement of at-risk youth.

PubMed

Schinke, S P; Cole, K C; Poulin, S R

2000-03-01

This study examined a non-school program aimed at enhancing the educational performance of economically disadvantaged early adolescents who live in public housing. The educational enhancement program included discussions with adults, writing activities, leisure reading, homework, helping others, and games using cognitive skills. A three-arm research design juxtaposed program youth who received educational enhancements with comparison youth in affiliated facilities who did not receive the program and with control youth in other community programs without educational enhancements. From youths, follow-up data collected 2 1/2 years after baseline revealed uniformly positive outcomes for program youth on measures of reading, verbal skills, writing, and tutoring. Teacher reports at final follow-up favored program and comparison youth over controls on measures of reading, writing, games, overall school performance, and interest in class material. School grades were higher for program youth than for comparison and control youth for reading, spelling, history, science, and social studies. Overall grade averages were higher for program youth versus comparisons and controls, as was school attendance. Study data lend empirical support to the provision of educational enhancements in non-school settings for at-risk youths.

Knowledge-Building Activity Structures in Japanese Elementary Science Pedagogy

ERIC Educational Resources Information Center

Oshima, Jun; Oshima, Ritsuko; Murayama, Isao; Inagaki, Shigenori; Takenaka, Makiko; Yamamoto, Tomokazu; Yamaguchi, Etsuji; Nakayama, Hayashi

2006-01-01

The purpose of this study is to refine Japanese elementary science activity structures by using a CSCL approach to transform the classroom into a knowledge-building community. We report design studies on two science lessons in two consecutive years and describe the progressive refinement of the activity structures. Through comparisons of student…

Investigating Test Equating Methods in Small Samples through Various Factors

ERIC Educational Resources Information Center

Asiret, Semih; Sünbül, Seçil Ömür

2016-01-01

In this study, equating methods for random group design using small samples through factors such as sample size, difference in difficulty between forms, and guessing parameter was aimed for comparison. Moreover, which method gives better results under which conditions was also investigated. In this study, 5,000 dichotomous simulated data…

Comparison of Traditional Methods with 3D Computer Models in the Instruction of Hepatobiliary Anatomy

ERIC Educational Resources Information Center

Keedy, Alexander W.; Durack, Jeremy C.; Sandhu, Parmbir; Chen, Eric M.; O'Sullivan, Patricia S.; Breiman, Richard S.

2011-01-01

This study was designed to determine whether an interactive three-dimensional presentation depicting liver and biliary anatomy is more effective for teaching medical students than a traditional textbook format presentation of the same material. Forty-six medical students volunteered for participation in this study. Baseline demographic…

An Exploratory Study of a Gender Equity Program for Secondary School Students.

ERIC Educational Resources Information Center

Freeman, John G.

1996-01-01

The effectiveness of a program designed to make secondary school students in Canada more aware of barriers to women in the workplace was studied in a preliminary development phase and a pilot test with 13 students and 23 comparisons. Results indicate that the instruction is effective in increasing student knowledge. (SLD)

A COMPARISON OF RESPONSE CONFIRMATION TECHNIQUES FOR AN ADJUNCTIVE SELF-STUDY PROGRAM.

ERIC Educational Resources Information Center

MEYER, DONALD E.

AN EXPERIMENT COMPARED THE EFFECTIVENESS OF FOUR METHODS OF CONFIRMING RESPONSES TO AN ADJUNCTIVE SELF-STUDY PROGRAM. THE PROGRAM WAS DESIGNED FOR AIR FORCE AIRCREWS UNDERTAKING A REFRESHER COURSE IN ENGINEERING. A SERIES OF SEQUENCED MULTIPLE CHOICE QUESTIONS EACH REFERRED TO A PAGE AND PARAGRAPH OF A PUBLICATION CONTAINING DETAILED INFORMATION…

A Comparison Study of Polyominoes Explorations in a Physical and Virtual Manipulative Environment

ERIC Educational Resources Information Center

Yuan, Y.; Lee, C. -Y.; Wang, C. -H.

2010-01-01

This study develops virtual manipulative, polyominoes kits for junior high school students to explore polyominoes. The current work conducts a non-equivalent group pretest-post-test quasi-experimental design to compare the performance difference between using physical manipulatives and virtual manipulatives in finding the number of polyominoes.…

Cultural Language Study: Grade 8.

ERIC Educational Resources Information Center

Tappenden, Jaqueline W.

Instructional materials provided in this second of a two-year sequence are designed to broaden and deepen the overview of Greek and Roman civilization and language developed in the initial year of study. Literary selections in the six units allow the student a comparison of themes and ideas in classical and contemporary literature. Major sections…

Mathematically Gifted Adolescent Females' Mixed Sentiment toward Gender Stereotypes

ERIC Educational Resources Information Center

Kao, Chen-yao

2015-01-01

There has been a paucity of research on gifted individuals' perceptions of gender stereotypes. The purpose of this study was to explore mathematically gifted adolescent females' perceptions of gender stereotypes through a research design of the qualitative multiple case study involving the constant comparison and the Three C's analysis scheme.…

Promoting Quality of Program Delivery via an Internet Message Delivery System

ERIC Educational Resources Information Center

Bishop, Dana C.; Dusenbury, Linda; Pankratz, Melinda M.; Hansen, William B.

2013-01-01

This article presents results from a study that evaluated an online message system designed to improve the delivery of prevention programs. We conducted a quasi-experimental study with 32 agencies and schools that implemented substance use prevention programs and examined differences between the comparison and intervention groups. We also examined…

Group Therapy Goals: A Comparison of Group Therapy Providers and Male Inmates

ERIC Educational Resources Information Center

Morgan, Robert D.; Garland, J. Travis; Rozycki, Alicia T.; Reich, Darcy A.; Wilson, Scott

2005-01-01

This study was designed to identify important process and content goals from the perspective of inmates and compare these goals to the goals identified by group therapists in a previous study conducted by Winterowd, Morgan, and Ferrell (2001). Utilizing survey data from 156 incarcerated adult males, an initial confirmatory factor analysis…

Hybrid and electric advanced vehicle systems (heavy) simulation

NASA Technical Reports Server (NTRS)

Hammond, R. A.; Mcgehee, R. K.

1981-01-01

A computer program to simulate hybrid and electric advanced vehicle systems (HEAVY) is described. It is intended for use early in the design process: concept evaluation, alternative comparison, preliminary design, control and management strategy development, component sizing, and sensitivity studies. It allows the designer to quickly, conveniently, and economically predict the performance of a proposed drive train. The user defines the system to be simulated using a library of predefined component models that may be connected to represent a wide variety of propulsion systems. The development of three models are discussed as examples.

Incidence of Verbal Comparisons in Beginners' Books and in Metaphor Comprehension Research: A Search for Ecological Validity.

ERIC Educational Resources Information Center

Broderick, Victor

1992-01-01

Classifies explicit verbal comparisons in 53 popular children's books both syntactically and semantically. Comparison types found in these books were contrasted with comparisons used as comprehension stimuli in extant developmental research. Implications for the design of future stimulus sets are discussed. (17 references) (GLR)

Social Studies Teacher Candidates' Opinions about Digital Citizenship and Its Place in Social Studies Teacher Training Program: A Comparison between the USA and Turkey

ERIC Educational Resources Information Center

Karaduman, Hidir

2017-01-01

This research aims to determine and compare what social studies teacher candidates living in two different countries think about digital citizenship and its place within social studies and social studies teacher training program and to produce suggestions concerning digital citizenship education. Having a descriptive design, this research has…

Steep discounting of delayed monetary and food rewards in obesity: a meta-analysis.

PubMed

Amlung, M; Petker, T; Jackson, J; Balodis, I; MacKillop, J

2016-08-01

An increasing number of studies have investigated delay discounting (DD) in relation to obesity, but with mixed findings. This meta-analysis synthesized the literature on the relationship between monetary and food DD and obesity, with three objectives: (1) to characterize the relationship between DD and obesity in both case-control comparisons and continuous designs; (2) to examine potential moderators, including case-control v. continuous design, money v. food rewards, sample sex distribution, and sample age (18 years); and (3) to evaluate publication bias. From 134 candidate articles, 39 independent investigations yielded 29 case-control and 30 continuous comparisons (total n = 10 278). Random-effects meta-analysis was conducted using Cohen's d as the effect size. Publication bias was evaluated using fail-safe N, Begg-Mazumdar and Egger tests, meta-regression of publication year and effect size, and imputation of missing studies. The primary analysis revealed a medium effect size across studies that was highly statistically significant (d = 0.43, p < 10-14). None of the moderators examined yielded statistically significant differences, although notably larger effect sizes were found for studies with case-control designs, food rewards and child/adolescent samples. Limited evidence of publication bias was present, although the Begg-Mazumdar test and meta-regression suggested a slightly diminishing effect size over time. Steep DD of food and money appears to be a robust feature of obesity that is relatively consistent across the DD assessment methodologies and study designs examined. These findings are discussed in the context of research on DD in drug addiction, the neural bases of DD in obesity, and potential clinical applications.

Wilderness Recreation Demand: A Comparison of Travel Cost and On-Site Cost Models

Treesearch

J.M. Bowker; A. Askew; L. Seymour; J.P. Zhu; D. English; C.M. Starbuck

2009-01-01

This study used travel cost and on-site day cost models, coupled with the Forest Service’s National Visitor Use Monitoring data, to examine the demand for and value of recreation access to designated Wilderness.

Analysis of corridor delay under SCATS control : FAST-TRAC Phase III deliverable

DOT National Transportation Integrated Search

1998-04-01

The study was designed to determine the change in travel time following the implementation of the Sydney Coordinated Adaptive Traffic System (SCATS) in Oakland County, Michigan. A before/after comparison was used to examine the change in travel time ...

Optimality, sample size, and power calculations for the sequential parallel comparison design.

PubMed

Ivanova, Anastasia; Qaqish, Bahjat; Schoenfeld, David A

2011-10-15

The sequential parallel comparison design (SPCD) has been proposed to increase the likelihood of success of clinical trials in therapeutic areas where high-placebo response is a concern. The trial is run in two stages, and subjects are randomized into three groups: (i) placebo in both stages; (ii) placebo in the first stage and drug in the second stage; and (iii) drug in both stages. We consider the case of binary response data (response/no response). In the SPCD, all first-stage and second-stage data from placebo subjects who failed to respond in the first stage of the trial are utilized in the efficacy analysis. We develop 1 and 2 degree of freedom score tests for treatment effect in the SPCD. We give formulae for asymptotic power and for sample size computations and evaluate their accuracy via simulation studies. We compute the optimal allocation ratio between drug and placebo in stage 1 for the SPCD to determine from a theoretical viewpoint whether a single-stage design, a two-stage design with placebo only in the first stage, or a two-stage design is the best design for a given set of response rates. As response rates are not known before the trial, a two-stage approach with allocation to active drug in both stages is a robust design choice. Copyright © 2011 John Wiley & Sons, Ltd.

Case study: Comparison of motivation for achieving higher performance between self-directed and manager-directed aerospace engineering teams

NASA Astrophysics Data System (ADS)

Erlick, Katherine

"The stereotype of engineers is that they are not people oriented; the stereotype implies that engineers would not work well in teams---that their task emphasis is a solo venture and does not encourage social aspects of collaboration" (Miner & Beyerlein, 1999, p. 16). The problem is determining the best method of providing a motivating environment where design engineers may contribute within a team in order to achieve higher performance in the organization. Theoretically, self-directed work teams perform at higher levels. But, allowing a design engineer to contribute to the team while still maintaining his or her anonymity is the key to success. Therefore, a motivating environment must be established to encourage greater self-actualization in design engineers. The purpose of this study is to determine the favorable motivational environment for design engineers and describe the comparison between two aerospace design-engineering teams: one self-directed and the other manager directed. Following the comparison, this study identified whether self-direction or manager-direction provides the favorable motivational environment for operating as a team in pursuit of achieving higher performance. The methodology used in this research was the case study focusing on the team's levels of job satisfaction and potential for higher performance. The collection of data came from three sources, (a) surveys, (b) researcher observer journal and (c) collection of artifacts. The surveys provided information regarding personal behavior characteristics, potentiality for higher performance and motivational attributes. The researcher journal provided information regarding team dynamics, individual interaction, conflict and conflict resolution. The milestone for performance was based on the collection of artifacts from the two teams. The findings from this study illustrated that whether the team was manager-directed or self-directed does not appear to influence the needs and wants of the team members. The self-directed team was more motivated to learn their topic than was the manager-directed team, but they struggled with their path in following their vision whereas the manager-directed team kept their focus under the guidance of their manager. Finally, both teams are in fact effective; however specific circumstances may be an important objective when deciding to utilize either a self-directed or manager-directed team.

The quiet revolution: reporting of health outcomes in general medical journals.

PubMed

Seymour, J; Newell, D; Shiell, A

1997-01-01

This study reviews the extent of evaluation of health outcomes in three general medical journals over the past decade by examining papers published in the original research section of the New England Journal of Medicine (NEJM), The Lancet, and the Medical Journal of Australia (MJA) in 1982 and 1992. Evaluations were identified and classified according to the type of comparison group and the type of outcome measures employed. They were divided into three categories: those employing a comparison group; those employing a before-and-after study design (or own comparison group); and those with no comparison group. The categories of outcome measures were mortality, clinical or intermediate measures of health state, and final outcome measures (quality of life). Results show that the proportion of papers evaluating a health services intervention remained stable over the period. However, the MJA published considerably fewer evaluations than the other journals. In the NEJM and The Lancet, 75 per cent of evaluations incorporated comparison groups, in the MJA, less than 40 per cent. Overall, the proportion of papers reporting final outcome measures increased significantly between 1982 and 1992 (p = 0.04) but the change in each journal individually did not reach statistical significance. This study indicates that the reporting of health outcomes evaluations has remained constant but there has been some change in the use of comparison groups and final outcome measures over time.

Changes in body composition over 8 years in a randomized trial of a lifestyle intervention: the look AHEAD study.

PubMed

Pownall, Henry J; Bray, George A; Wagenknecht, Lynne E; Walkup, Michael P; Heshka, Stanley; Hubbard, Van S; Hill, James; Kahn, Steven E; Nathan, David M; Schwartz, Anne V; Johnson, Karen C

2015-03-01

To determine the effects of an intensive lifestyle intervention versus a comparison group on body composition in obese or overweight persons with type 2 diabetes at baseline and at 1, 4, and 8 years. Body composition was measured by dual-energy X-ray absorptiometry in a subset of 1019 Look AHEAD study volunteers randomized to intervention or comparison groups. The intervention was designed to achieve and maintain ≥7% weight loss through increased physical activity and reduced caloric intake. The comparison group received social support and diabetes education. At 1 year, the intervention group lost fat (5.6 ± 0.2 kg) and lean mass (2.3 ± 0.1 kg) but regained fat (∼100%) and lost lean mass between years 1 and 8. Between baseline and year 8, weight loss was greater in intervention versus comparison groups (4.0 ± 0.4 vs. 2.3 ± 0.4 kg); comparison group weight loss was mostly lean mass (2.1 ± 0.17 kg). Fat mass in the intervention group was lower than that of the comparison group at all post-baseline time points. Reduced fat mass may place the intervention group at a lower risk of obesity-linked sequelae, a hypothesis that can be tested by future studies of this cohort. © 2015 The Obesity Society.

Use of nonlinear design optimization techniques in the comparison of battery discharger topologies for the space platform

NASA Technical Reports Server (NTRS)

Sable, Dan M.; Cho, Bo H.; Lee, Fred C.

1990-01-01

A detailed comparison of a boost converter, a voltage-fed, autotransformer converter, and a multimodule boost converter, designed specifically for the space platform battery discharger, is performed. Computer-based nonlinear optimization techniques are used to facilitate an objective comparison. The multimodule boost converter is shown to be the optimum topology at all efficiencies. The margin is greatest at 97 percent efficiency. The multimodule, multiphase boost converter combines the advantages of high efficiency, light weight, and ample margin on the component stresses, thus ensuring high reliability.

Novel parameter-based flexure bearing design method

NASA Astrophysics Data System (ADS)

Amoedo, Simon; Thebaud, Edouard; Gschwendtner, Michael; White, David

2016-06-01

A parameter study was carried out on the design variables of a flexure bearing to be used in a Stirling engine with a fixed axial displacement and a fixed outer diameter. A design method was developed in order to assist identification of the optimum bearing configuration. This was achieved through a parameter study of the bearing carried out with ANSYS®. The parameters varied were the number and the width of the arms, the thickness of the bearing, the eccentricity, the size of the starting and ending holes, and the turn angle of the spiral. Comparison was made between the different designs in terms of axial and radial stiffness, the natural frequency, and the maximum induced stresses. Moreover, the Finite Element Analysis (FEA) was compared to theoretical results for a given design. The results led to a graphical design method which assists the selection of flexure bearing geometrical parameters based on pre-determined geometric and material constraints.

An analysis of adaptive design variations on the sequential parallel comparison design for clinical trials

PubMed Central

Mi, Michael Y.; Betensky, Rebecca A.

2013-01-01

Background Currently, a growing placebo response rate has been observed in clinical trials for antidepressant drugs, a phenomenon that has made it increasingly difficult to demonstrate efficacy. The sequential parallel comparison design (SPCD) is a clinical trial design that was proposed to address this issue. The SPCD theoretically has the potential to reduce the sample size requirement for a clinical trial and to simultaneously enrich the study population to be less responsive to the placebo. Purpose Because the basic SPCD design already reduces the placebo response by removing placebo responders between the first and second phases of a trial, the purpose of this study was to examine whether we can further improve the efficiency of the basic SPCD and if we can do so when the projected underlying drug and placebo response rates differ considerably from the actual ones. Methods Three adaptive designs that used interim analyses to readjust the length of study duration for individual patients were tested to reduce the sample size requirement or increase the statistical power of the SPCD. Various simulations of clinical trials using the SPCD with interim analyses were conducted to test these designs through calculations of empirical power. Results From the simulations, we found that the adaptive designs can recover unnecessary resources spent in the traditional SPCD trial format with overestimated initial sample sizes and provide moderate gains in power. Under the first design, results showed up to a 25% reduction in person-days, with most power losses below 5%. In the second design, results showed up to a 8% reduction in person-days with negligible loss of power. In the third design using sample size re-estimation, up to 25% power was recovered from underestimated sample size scenarios. Limitations Given the numerous possible test parameters that could have been chosen for the simulations, the study’s results are limited to situations described by the parameters that were used, and may not generalize to all possible scenarios. Furthermore, drop-out of patients is not considered in this study. Conclusions It is possible to make an already complex design such as the SPCD adaptive, and thus more efficient, potentially overcoming the problem of placebo response at lower cost. Ultimately, such a design may expedite the approval of future effective treatments. PMID:23283576

Comparison of Fire Model Predictions with Experiments Conducted in a Hangar With a 15 Meter Ceiling

NASA Technical Reports Server (NTRS)

Davis, W. D.; Notarianni, K. A.; McGrattan, K. B.

1996-01-01

The purpose of this study is to examine the predictive capabilities of fire models using the results of a series of fire experiments conducted in an aircraft hangar with a ceiling height of about 15 m. This study is designed to investigate model applicability at a ceiling height where only a limited amount of experimental data is available. This analysis deals primarily with temperature comparisons as a function of distance from the fire center and depth beneath the ceiling. Only limited velocity measurements in the ceiling jet were available but these are also compared with those models with a velocity predictive capability.

Addiction and “Generation Me:” Narcissistic and Prosocial Behaviors of Adolescents with Substance Dependency Disorder in Comparison to Normative Adolescents

PubMed Central

CARTER, REBECCA R.; JOHNSON, SHANNON M.; EXLINE, JULIE J.; POST, STEPHEN G.; PAGANO, MARIA E.

2012-01-01

The purpose of this study is to explore narcissistic and prosocial behaviors as reported by adolescents with and without substance dependency disorder (SDD). This study employs a quasi-experimental design using SDD adolescents compared with two normative samples of adolescents. In comparison to normative adolescents, adolescents with SDD were strongly distinguished by overt narcissistic behaviors and less monetary giving. Levels of narcissistic and prosocial behaviors among adolescents with SDD suggest a connection between self-centeredness and addiction. Results also suggest volunteerism as a potential option to counter narcissism in substance dependent adolescents. PMID:22544995

Osiris and SOMBRERO inertial confinement fusion power plant designs. Volume 2, Designs, assessments, and comparisons, Final report

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

Meier, W.R.; Bieri, R.L.; Monsler, M.J.

1992-03-01

The primary objective of the of the IFE Reactor Design Studies was to provide the Office of Fusion Energy with an evaluation of the potential of inertial fusion for electric power production. The term reactor studies is somewhat of a misnomer since these studies included the conceptual design and analysis of all aspects of the IFE power plants: the chambers, heat transport and power conversion systems, other balance of plant facilities, target systems (including the target production, injection, and tracking systems), and the two drivers. The scope of the IFE Reactor Design Studies was quite ambitious. The majority of ourmore » effort was spent on the conceptual design of two IFE electric power plants, one using an induction linac heavy ion beam (HIB) driver and the other using a Krypton Fluoride (KrF) laser driver. After the two point designs were developed, they were assessed in terms of their (1) environmental and safety aspects; (2) reliability, availability, and maintainability; (3) technical issues and technology development requirements; and (4) economics. Finally, we compared the design features and the results of the assessments for the two designs.« less

Risk Evaluation in the Pre-Phase A Conceptual Design of Spacecraft

NASA Technical Reports Server (NTRS)

Fabisinski, Leo L., III; Maples, Charlotte Dauphne

2010-01-01

Typically, the most important decisions in the design of a spacecraft are made in the earliest stages of its conceptual design the Pre-Phase A stages. It is in these stages that the greatest number of design alternatives is considered, and the greatest number of alternatives is rejected. The focus of Pre-Phase A conceptual development is on the evaluation and comparison of whole concepts and the larger-scale systems comprising those concepts. This comparison typically uses general Figures of Merit (FOMs) to quantify the comparative benefits of designs and alternative design features. Along with mass, performance, and cost, risk should be one of the major FOMs in evaluating design decisions during the conceptual design phases. However, risk is often given inadequate consideration in conceptual design practice. The reasons frequently given for this lack of attention to risk include: inadequate mission definition, lack of rigorous design requirements in early concept phases, lack of fidelity in risk assessment methods, and under-evaluation of risk as a viable FOM for design evaluation. In this paper, the role of risk evaluation in early conceptual design is discussed. The various requirements of a viable risk evaluation tool at the Pre-Phase A level are considered in light of the needs of a typical spacecraft design study. A technique for risk identification and evaluation is presented. The application of the risk identification and evaluation approach to the conceptual design process is discussed. Finally, a computational tool for risk profiling is presented and applied to assess the risk for an existing Pre-Phase A proposal. The resulting profile is compared to the risks identified for the proposal by other means.

Compared with what? An analysis of control-group types in Cochrane and Campbell reviews of psychosocial treatment efficacy with substance use disorders.

PubMed

Karlsson, Patrik; Bergmark, Anders

2015-03-01

A crucial, but under-appreciated, aspect in experimental research on psychosocial treatments of substance use disorders concerns what kinds of control groups are used. This paper examines how the distinction between different control-group designs have been handled by the Cochrane and the Campbell Collaborations in their systematic reviews of psychosocial treatments of substance abuse disorders. We assessed Cochrane and Campbell reviews (n = 8) that were devoted to psychosocial treatments of substance use disorders. We noted what control groups were considered and analysed the extent to which the reviews provided a rationale for chosen comparison conditions. We also analysed whether type of control group in the primary studies influenced how the reviews framed the effects discussed and whether this was related to conclusions drawn. The reviews covered studies involving widely different control conditions. Overall, little attention was paid to the use of different control groups (e.g. head-to-head comparisons versus untreated controls) and what this implies when interpreting effect sizes. Seven of eight reviews did not provide a rationale for the choice of comparison conditions. Cochrane and Campbell reviews of the efficacy of psychosocial interventions with substance use disorders seem to underappreciate that the use of different control-group types yields different effect estimates. Most reviews have not distinguished between different control-group designs and therefore have provided a confused picture regarding absolute and relative treatment efficacy. A systematic approach to treating different control-group designs in research reviews is necessary for meaningful estimates of treatment efficacy. © 2014 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.

OTEC riser cable system, Phase II: conceptual design

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

Not Available

1980-10-01

Studies are summarized of conceptual designs of riser cable systems for OTEC pilot plants of both the spar and plantship configurations located at sites off the southeast coast of Puerto Rico. The studies utilize a baseline pilot plant riser cable, the design of which has been developed and reported on in other reports. Baseline riser cable systems for OTEC pilot plants are identified, system hardware consistent with these designs are conceptualized, and comparisons of the various system concepts are provided. It is concluded that there are three riser cable systems feasible for a spar pilot plant platform at the Puntamore » Yeguas site, and two riser cable systems feasible at the plantship pilot plant at the Punta Tuna site. Recommendations for further investigations in the areas of materials, hardware design and pre-installation site surveys are also addressed.« less

An adaptive two-stage dose-response design method for establishing proof of concept.

PubMed

Franchetti, Yoko; Anderson, Stewart J; Sampson, Allan R

2013-01-01

We propose an adaptive two-stage dose-response design where a prespecified adaptation rule is used to add and/or drop treatment arms between the stages. We extend the multiple comparison procedures-modeling (MCP-Mod) approach into a two-stage design. In each stage, we use the same set of candidate dose-response models and test for a dose-response relationship or proof of concept (PoC) via model-associated statistics. The stage-wise test results are then combined to establish "global" PoC using a conditional error function. Our simulation studies showed good and more robust power in our design method compared to conventional and fixed designs.

A Comparison of Case Study and Traditional Teaching Methods for Improvement of Oral Communication and Critical-Thinking Skills

ERIC Educational Resources Information Center

Noblitt, Lynnette; Vance, Diane E.; Smith, Michelle L. DePoy

2010-01-01

This study compares a traditional paper presentation approach and a case study method for the development and improvement of oral communication skills and critical-thinking skills in a class of junior forensic science majors. A rubric for rating performance in these skills was designed on the basis of the oral communication competencies developed…

A Study to Determine the Academic Progression between Economically Disadvantaged Students and Their Economically Advantaged Peers on Georgia's Statewide Criteria Referenced Competency Test

ERIC Educational Resources Information Center

Warner, Tonya

2009-01-01

This quantitative study implemented a non-experimental design that was descriptive, ex-post facto, and longitudinal. This study is examining economically disadvantaged students (EDS) with comparison to non-economically disadvantaged students (non-EDS) and their academic performance on Georgia's Criterion-Referenced Competency Tests (CRCT).…

Apollo guidance, navigation, and control: Candidate configuration trade study, Stellar-Inertial Measurement System (SIMS) for an Earth Observation Satellite (EOS)

NASA Technical Reports Server (NTRS)

Ogletree, G.; Coccoli, J.; Mckern, R.; Smith, M.; White, R.

1972-01-01

The ten candidate SIMS configurations were reduced to three in preparation for the final trade comparison. The report emphasizes subsystem design trades, star availability studies, data processing (smoothing) methods, and the analytical and simulation studies at subsystem and system levels from which candidate accuracy estimates will be presented.

Environmental Literacy of Pre-Service Teachers in Israel: A Comparison between Students at the Onset and End of Their Studies

ERIC Educational Resources Information Center

Yavetz, Bela; Goldman, Daphne; Pe'er, Sara

2009-01-01

The adequate preparation of teacher education students in environmental education is a prerequisite for their future ability to design and implement effective environmental education. This longitudinal study compared the environmental literacy of 214 students at the onset and towards the end of their studies, in three academic colleges of…

Blending Physical and Virtual Manipulatives: An Effort to Improve Students' Conceptual Understanding through Science Laboratory Experimentation

ERIC Educational Resources Information Center

Olympiou, Georgios; Zacharia, Zacharias C.

2012-01-01

This study aimed to investigate the effect of experimenting with physical manipulatives (PM), virtual manipulatives (VM), and a blended combination of PM and VM on undergraduate students' understanding of concepts in the domain of "Light and Color." A pre-post comparison study design was used for the purposes of this study that involved 70…

A Comparison of Student Teachers' Beliefs from Four Different Science Teaching Domains Using a Mixed Methods Design

ERIC Educational Resources Information Center

Markic, Silvija; Eilks, Ingo

2012-01-01

The study presented in this paper integrates data from four combined research studies, which are both qualitative and quantitative in nature. The studies describe freshman science student teachers' beliefs about teaching and learning. These freshmen intend to become teachers in Germany in one of four science teaching domains (secondary biology,…

A Comparison of Rubrics and Graded Category Rating Scales with Various Methods Regarding Raters' Reliability

ERIC Educational Resources Information Center

Dogan, C. Deha; Uluman, Müge

2017-01-01

The aim of this study was to determine the extent at which graded-category rating scales and rubrics contribute to inter-rater reliability. The research was designed as a correlational study. Study group consisted of 82 students attending sixth grade and three writing course teachers in a private elementary school. A performance task was…

Effects of Integrating Children's Literature and DVD Films into a College EFL Class

ERIC Educational Resources Information Center

Chen, Mei-Ling

2012-01-01

The purpose of the study was to investigate the effects of the use of children's literature and DVD films on EFL adult language learning. A total of 89 non-English majors enrolled in two Freshman English classes participated in the study. The study employed a quasi-experimental, pretest/posttest comparison group design. The participants in the…

The Effects of Improvisational Music Therapy on Joint Attention Behaviors in Autistic Children: A Randomized Controlled Study

ERIC Educational Resources Information Center

Kim, Jinah; Wigram, Tony; Gold, Christian

2008-01-01

The purpose of this study was to investigate the effects of improvisational music therapy on joint attention behaviors in pre-school children with autism. It was a randomized controlled study employing a single subject comparison design in two different conditions, improvisational music therapy and play sessions with toys, and using standardized…

Mathematics Curriculum Based Measurement to Predict State Test Performance: A Comparison of Measures and Methods

ERIC Educational Resources Information Center

Stevens, Olinger; Leigh, Erika

2012-01-01

Scope and Method of Study: The purpose of the study is to use an empirical approach to identify a simple, economical, efficient, and technically adequate performance measure that teachers can use to assess student growth in mathematics. The current study has been designed to expand the body of research for math CBM to further examine technical…

Preliminary design studies on a nuclear seawater desalination system

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

Wibisono, A. F.; Jung, Y. H.; Choi, J.

2012-07-01

Seawater desalination is one of the most promising technologies to provide fresh water especially in the arid region. The most used technology in seawater desalination are thermal desalination (MSF and MED) and membrane desalination (RO). Some developments have been done in the area of coupling the desalination plant with a nuclear reactor to reduce the cost of energy required in thermal desalination. The coupling a nuclear reactor to a desalination plant can be done either by using the co-generation or by using dedicated heat from a nuclear system. The comparison of the co-generation nuclear reactor with desalination plant, dedicated nuclearmore » heat system, and fossil fueled system will be discussed in this paper using economical assessment with IAEA DEEP software. A newly designed nuclear system dedicated for the seawater desalination will also be suggested by KAIST (Korea Advanced Inst. of Science and Technology) research team and described in detail within this paper. The suggested reactor system is using gas cooled type reactor and in this preliminary study the scope of design will be limited to comparison of two cases in different operating temperature ranges. (authors)« less

Transfer of control system interface solutions from other domains to the thermal power industry.

PubMed

Bligård, L-O; Andersson, J; Osvalder, A-L

2012-01-01

In a thermal power plant the operators' roles are to control and monitor the process to achieve efficient and safe production. To achieve this, the human-machine interfaces have a central part. The interfaces need to be updated and upgraded together with the technical functionality to maintain optimal operation. One way of achieving relevant updates is to study other domains and see how they have solved similar issues in their design solutions. The purpose of this paper is to present how interface design solution ideas can be transferred from domains with operator control to thermal power plants. In the study 15 domains were compared using a model for categorisation of human-machine systems. The result from the domain comparison showed that nuclear power, refinery and ship engine control were most similar to thermal power control. From the findings a basic interface structure and three specific display solutions were proposed for thermal power control: process parameter overview, plant overview, and feed water view. The systematic comparison of the properties of a human-machine system allowed interface designers to find suitable objects, structures and navigation logics in a range of domains that could be transferred to the thermal power domain.

A fuselage/tank structure study for actively cooled hypersonic cruise vehicles, summary. [aircraft design of aircraft fuel systems

NASA Technical Reports Server (NTRS)

Pirrello, C. J.; Baker, A. H.; Stone, J. E.

1976-01-01

A detailed analytical study was made to investigate the effects of fuselage cross section (circular and elliptical) and the structural arrangement (integral and nonintegral tanks) on aircraft performance. The vehicle was a 200 passenger, liquid hydrogen fueled Mach 6 transport designed to meet a range goal of 9.26 Mn (5000 NM). A variety of trade studies were conducted in the area of configuration arrangement, structural design, and active cooling design in order to maximize the performance of each of three point design aircraft: (1) circular wing-body with nonintegral tanks, (2) circular wing-body with integral tanks and (3) elliptical blended wing-body with integral tanks. Aircraft range and weight were used as the basis for comparison. The resulting design and performance characteristics show that the blended body integral tank aircraft weights the least and has the greatest range capability, however, producibility and maintainability factors favor nonintegral tank concepts.

Preliminary design study of a baseline MIUS

NASA Technical Reports Server (NTRS)

Wolfer, B. M.; Shields, V. E.; Rippey, J. O.; Roberts, H. L.; Wadle, R. C.; Wallin, S. P.; Gill, W. L.; White, E. H.; Monzingo, R.

1977-01-01

Results of a conceptual design study to establish a baseline design for a modular integrated utility system (MIUS) are presented. The system concept developed a basis for evaluating possible projects to demonstrate an MIUS. For the baseline study, climate conditions for the Washington, D.C., area were used. The baseline design is for a high density apartment complex of 496 dwelling units with a planned full occupancy of approximately 1200 residents. Environmental considerations and regulations for the MIUS installation are discussed. Detailed cost data for the baseline MIUS are given together with those for design and operating variations under climate conditions typified by Las Vegas, Nevada, Houston, Texas, and Minneapolis, Minnesota. In addition, results of an investigation of size variation effects, for 300 and 1000 unit apartment complexes, are presented. Only conceptual aspects of the design are discussed. Results regarding energy savings and costs are intended only as trend information and for use in relative comparisons. Alternate heating, ventilation, and air conditioning concepts are considered in the appendix.

A SOFTWARE TOOL TO COMPARE MEASURED AND SIMULATED BUILDING ENERGY PERFORMANCE DATA

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

Maile, Tobias; Bazjanac, Vladimir; O'Donnell, James

2011-11-01

Building energy performance is often inadequate when compared to design goals. To link design goals to actual operation one can compare measured with simulated energy performance data. Our previously developed comparison approach is the Energy Performance Comparison Methodology (EPCM), which enables the identification of performance problems based on a comparison of measured and simulated performance data. In context of this method, we developed a software tool that provides graphing and data processing capabilities of the two performance data sets. The software tool called SEE IT (Stanford Energy Efficiency Information Tool) eliminates the need for manual generation of data plots andmore » data reformatting. SEE IT makes the generation of time series, scatter and carpet plots independent of the source of data (measured or simulated) and provides a valuable tool for comparing measurements with simulation results. SEE IT also allows assigning data points on a predefined building object hierarchy and supports different versions of simulated performance data. This paper briefly introduces the EPCM, describes the SEE IT tool and illustrates its use in the context of a building case study.« less

DHS small-scale safety and thermal testing of improvised explosives-comparison of testing performance

NASA Astrophysics Data System (ADS)

Reynolds, J. G.; Sandstrom, M. M.; Brown, G. W.; Warner, K. F.; Phillips, J. J.; Shelley, T. J.; Reyes, J. A.; Hsu, P. C.

2014-05-01

One of the first steps in establishing safe handling procedures for explosives is small-scale safety and thermal (SSST) testing. To better understand the response of improvised materials or homemade explosives (HMEs) to SSST testing, 16 HME materials were compared to three standard military explosives in a proficiency-type round robin study among five laboratories-two DoD and three DOE-sponsored by DHS. The testing matrix has been designed to address problems encountered with improvised materials-powder mixtures, liquid suspensions, partially wetted solids, immiscible liquids, and reactive materials. More than 30 issues have been identified that indicate standard test methods may require modification when applied to HMEs to derive accurate sensitivity assessments needed for developing safe handling and storage practices. This paper presents a generalized comparison of the results among the testing participants, comparison of friction results from BAM (German Bundesanstalt für Materi-alprüfung) and ABL (Allegany Ballistics Laboratory) designed testing equipment, and an overview of the statistical results from the RDX (1,3,5-Trinitroperhydro-1,3,5-triazine) standard tested throughout the proficiency test.

Network meta-analysis combining individual patient and aggregate data from a mixture of study designs with an application to pulmonary arterial hypertension.

PubMed

Thom, Howard H Z; Capkun, Gorana; Cerulli, Annamaria; Nixon, Richard M; Howard, Luke S

2015-04-12

Network meta-analysis (NMA) is a methodology for indirectly comparing, and strengthening direct comparisons of two or more treatments for the management of disease by combining evidence from multiple studies. It is sometimes not possible to perform treatment comparisons as evidence networks restricted to randomized controlled trials (RCTs) may be disconnected. We propose a Bayesian NMA model that allows to include single-arm, before-and-after, observational studies to complete these disconnected networks. We illustrate the method with an indirect comparison of treatments for pulmonary arterial hypertension (PAH). Our method uses a random effects model for placebo improvements to include single-arm observational studies into a general NMA. Building on recent research for binary outcomes, we develop a covariate-adjusted continuous-outcome NMA model that combines individual patient data (IPD) and aggregate data from two-arm RCTs with the single-arm observational studies. We apply this model to a complex comparison of therapies for PAH combining IPD from a phase-III RCT of imatinib as add-on therapy for PAH and aggregate data from RCTs and single-arm observational studies, both identified by a systematic review. Through the inclusion of observational studies, our method allowed the comparison of imatinib as add-on therapy for PAH with other treatments. This comparison had not been previously possible due to the limited RCT evidence available. However, the credible intervals of our posterior estimates were wide so the overall results were inconclusive. The comparison should be treated as exploratory and should not be used to guide clinical practice. Our method for the inclusion of single-arm observational studies allows the performance of indirect comparisons that had previously not been possible due to incomplete networks composed solely of available RCTs. We also built on many recent innovations to enable researchers to use both aggregate data and IPD. This method could be used in similar situations where treatment comparisons have not been possible due to restrictions to RCT evidence and where a mixture of aggregate data and IPD are available.

Optimization for minimum sensitivity to uncertain parameters

NASA Technical Reports Server (NTRS)

Pritchard, Jocelyn I.; Adelman, Howard M.; Sobieszczanski-Sobieski, Jaroslaw

1994-01-01

A procedure to design a structure for minimum sensitivity to uncertainties in problem parameters is described. The approach is to minimize directly the sensitivity derivatives of the optimum design with respect to fixed design parameters using a nested optimization procedure. The procedure is demonstrated for the design of a bimetallic beam for minimum weight with insensitivity to uncertainties in structural properties. The beam is modeled with finite elements based on two dimensional beam analysis. A sequential quadratic programming procedure used as the optimizer supplies the Lagrange multipliers that are used to calculate the optimum sensitivity derivatives. The method was perceived to be successful from comparisons of the optimization results with parametric studies.

The efficiency of health care production in OECD countries: A systematic review and meta-analysis of cross-country comparisons.

PubMed

Varabyova, Yauheniya; Müller, Julia-Maria

2016-03-01

There has been an ongoing interest in the analysis and comparison of the efficiency of health care systems using nonparametric and parametric applications. The objective of this study was to review the current state of the literature and to synthesize the findings on health system efficiency in OECD countries. We systematically searched five electronic databases through August 2014 and identified 22 studies that analyzed the efficiency of health care production at the country level. We summarized these studies with view on their sample, methods, and utilized variables. We developed and applied a checklist of 14 items to assess the quality of the reviewed studies along four dimensions: reporting, external validity, bias, and power. Moreover, to examine the internal validity of findings we meta-analyzed the efficiency estimates reported in 35 models from ten studies. The qualitative synthesis of the literature indicated large differences in study designs and methods. The meta-analysis revealed low correlations between country rankings suggesting a lack of internal validity of the efficiency estimates. In conclusion, methodological problems of existing cross-country comparisons of the efficiency of health care systems draw into question the ability of these comparisons to provide meaningful guidance to policy-makers. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The Effect of an Authentic Acute Physical Education Session of Dance on Elementary Students' Selective Attention

PubMed Central

Stylianou, M.; Dyson, B.; Banville, D.; Dryden, C.; Colby, R.

2018-01-01

There have been calls to test the potential benefits of different forms of physical activity (PA) to executive function, particularly in authentic settings. Hence, the purpose of this study was to investigate the effect of an acute dance session within an existing physical education class on students' selective attention. The study employed a pre/posttest quasi-experimental design with a comparison group in one Aotearoa, New Zealand, primary school. Participants were 192 students (comparison group = 104 students) in Years 5 and 6. The intervention group participated in a dance-based physical education lesson while the comparison group continued their regular classroom work. PA during the physical education lesson was monitored using accelerometers. Selective attention was assessed at pretest and after the comparison/physical education sessions with the d2 Test of Attention. 2 × 2 ANOVA results suggested a significant time effect for all three measures, no significant group effects for any measures, and significant time by group interactions for TN and CP but not for E%. The intervention group improved significantly more than the comparison group for TN and CP. This study's findings suggest that existing school opportunities focused on cognitively engaging PA, such as dance, can improve aspects of students' selective attention. PMID:29662903

The Effect of an Authentic Acute Physical Education Session of Dance on Elementary Students' Selective Attention.

PubMed

Kulinna, P H; Stylianou, M; Dyson, B; Banville, D; Dryden, C; Colby, R

2018-01-01

There have been calls to test the potential benefits of different forms of physical activity (PA) to executive function, particularly in authentic settings. Hence, the purpose of this study was to investigate the effect of an acute dance session within an existing physical education class on students' selective attention. The study employed a pre/posttest quasi-experimental design with a comparison group in one Aotearoa, New Zealand, primary school. Participants were 192 students (comparison group = 104 students) in Years 5 and 6. The intervention group participated in a dance-based physical education lesson while the comparison group continued their regular classroom work. PA during the physical education lesson was monitored using accelerometers. Selective attention was assessed at pretest and after the comparison/physical education sessions with the d2 Test of Attention. 2 × 2 ANOVA results suggested a significant time effect for all three measures, no significant group effects for any measures, and significant time by group interactions for TN and CP but not for E %. The intervention group improved significantly more than the comparison group for TN and CP. This study's findings suggest that existing school opportunities focused on cognitively engaging PA, such as dance, can improve aspects of students' selective attention.

DEVELOPMENT OF A PROTOCOL FOR TESTING EFFECTS OF TOXIC SUBSTANCES ON PLANTS

EPA Science Inventory

This study was designed to devise a rapid, simple, reproducible bioassay procedure to determine effects of so-called 'toxic substances in the environment' on vegetation and provide a standardized procedure for evaluation and comparison of effects of diverse compounds. Eight diffe...

Mini-Society vs. Token Economy: An Experimental Comparison of the Effects on Learning and Autonomy of Socially Emergent and Imposed Behavior Modification

ERIC Educational Resources Information Center

Kourilsky, Marilyn; Hirshleifer, Jack

1976-01-01

This study compares the effects of two teacher training programs designed to emphasize one of two forms of behavior modification in teaching economics to fourth-, fifth-, and sixth-grade pupils. (DMT)

Rho-Isp Revisited and Basic Stage Mass Estimating for Launch Vehicle Conceptual Sizing Studies

NASA Technical Reports Server (NTRS)

Kibbey, Timothy P.

2015-01-01

The ideal rocket equation is manipulated to demonstrate the essential link between propellant density and specific impulse as the two primary stage performance drivers for a launch vehicle. This is illustrated by examining volume-limited stages such as first stages and boosters. This proves to be a good approximation for first-order or Phase A vehicle design studies for solid rocket motors and for liquid stages, except when comparing to hydrogen-fueled stages. A next-order mass model is developed that is able to model the mass differences between hydrogen-fueled and other stages. Propellants considered range in density from liquid methane to inhibited red fuming nitric acid. Calculated comparisons are shown for solid rocket boosters, liquid first stages, liquid upper stages, and a balloon-deployed single-stage-to-orbit concept. The derived relationships are ripe for inclusion in a multi-stage design space exploration and optimization algorithm, as well as for single-parameter comparisons such as those shown herein.

Retrofit of CD-6 (Smith) impeller in fermentation vessels.

PubMed

Junker, B H; Mann, Z; Hunt, G

2000-10-01

We extended prior studies on the influence of impeller type on fermentation performance to include a novel low-power-number, high-efficiency radial flow impeller, the CD-6, possessing six curved blades on a disk turbine. Dual impeller combinations of CD-6/CD-6, CD-6/Maxflo T, and CD-6/HE-3 were compared with Rushton/Rushton and Maxflo T/Maxflo T base cases. Qualitative comparisons of unaerated and aerated power draw in both water and glycerol were conducted. These suggested minimal power drops with aeration for dual CD-6 impellers and hybrids containing the CD-6 impeller design. We also examined fermentation performance for Streptomyces and Glarea secondary metabolite fermentations. A qualitative comparison of the data suggested that dual CD-6 impellers and hybrids containing the CD-6 impeller design resulted in reasonable power draws, improved mass transfer rates with airflow increases, and acceptable peak titers. These arrangements may warrant further study under a wider range of production conditions.

Bayesian cross-entropy methodology for optimal design of validation experiments

NASA Astrophysics Data System (ADS)

Jiang, X.; Mahadevan, S.

2006-07-01

An important concern in the design of validation experiments is how to incorporate the mathematical model in the design in order to allow conclusive comparisons of model prediction with experimental output in model assessment. The classical experimental design methods are more suitable for phenomena discovery and may result in a subjective, expensive, time-consuming and ineffective design that may adversely impact these comparisons. In this paper, an integrated Bayesian cross-entropy methodology is proposed to perform the optimal design of validation experiments incorporating the computational model. The expected cross entropy, an information-theoretic distance between the distributions of model prediction and experimental observation, is defined as a utility function to measure the similarity of two distributions. A simulated annealing algorithm is used to find optimal values of input variables through minimizing or maximizing the expected cross entropy. The measured data after testing with the optimum input values are used to update the distribution of the experimental output using Bayes theorem. The procedure is repeated to adaptively design the required number of experiments for model assessment, each time ensuring that the experiment provides effective comparison for validation. The methodology is illustrated for the optimal design of validation experiments for a three-leg bolted joint structure and a composite helicopter rotor hub component.

Communicating Patient Status: Comparison of Teaching Strategies in Prelicensure Nursing Education.

PubMed

Lanz, Amelia S; Wood, Felecia G

Research indicates that nurses lack adequate preparation for reporting patient status. This study compared 2 instructional methods focused on patient status reporting in the clinical setting using a randomized posttest-only comparison group design. Reporting performance using a standardized communication framework and student perceptions of satisfaction and confidence with learning were measured in a simulated event that followed the instruction. Between the instructional methods, there was no statistical difference in student reporting performance or perceptions of learning. Performance evaluations provided helpful insights for the nurse educator.

Evaluation of a New Dental Implant Cervical Design in Comparison with a Conventional Design in an Experimental American Foxhound Model

PubMed Central

Pérez-Albacete Martínez, Maria Ángeles; Maté Sánchez De Val, José Eduardo; Ramos Oltra, María Luisa; Fernández Domínguez, Manuel

2018-01-01

The aim of this study was to evaluate osseointegration and crestal bone height in implants with a triangular cervical design in comparison with a standard rounded cervical design. The control group consisted of 24 implants with a standard cervical design, and the test group of 24 implants with a triangular cervical design. The implants were inserted in healed bone in six American Foxhounds. Crestal bone height and tissue thickness in the cervical portion were measured after 12 weeks healing. Data analysis found mean crestal bone loss of: 0.31 ± 0.24 mm on the buccal side, 0.35 ± 0.14 mm on the lingual in the test group, and 0.71 ± 0.28 mm buccal loss, and 0.42 ± 0.30 mm lingual in the control group; with statistically significant differences on the buccal aspect (p = 0.0019). Mean tissue thickness in the test group was 1.98 ± 0.17 mm on the buccal aspect, and 2.43 ± 0.93 mm in the lingual; in the control group it was 2.48 ± 0.61 mm buccal thickness, and 2.88 ± 0.14 mm lingual, with significant differences on both aspects (p = 0.0043; p = 0.0029). The results suggest that greater thickness of peri-implant tissue can be expected when the triangular cervical implant design is used rather than the standard cervical design. PMID:29561788

Evaluation of a New Dental Implant Cervical Design in Comparison with a Conventional Design in an Experimental American Foxhound Model.

PubMed

Pérez-Albacete Martínez, Maria Ángeles; Pérez-Albacete Martínez, Carlos; Maté Sánchez De Val, José Eduardo; Ramos Oltra, María Luisa; Fernández Domínguez, Manuel; Calvo Guirado, Jose Luis

2018-03-21

The aim of this study was to evaluate osseointegration and crestal bone height in implants with a triangular cervical design in comparison with a standard rounded cervical design. The control group consisted of 24 implants with a standard cervical design, and the test group of 24 implants with a triangular cervical design. The implants were inserted in healed bone in six American Foxhounds. Crestal bone height and tissue thickness in the cervical portion were measured after 12 weeks healing. Data analysis found mean crestal bone loss of: 0.31 ± 0.24 mm on the buccal side, 0.35 ± 0.14 mm on the lingual in the test group, and 0.71 ± 0.28 mm buccal loss, and 0.42 ± 0.30 mm lingual in the control group; with statistically significant differences on the buccal aspect ( p = 0.0019). Mean tissue thickness in the test group was 1.98 ± 0.17 mm on the buccal aspect, and 2.43 ± 0.93 mm in the lingual; in the control group it was 2.48 ± 0.61 mm buccal thickness, and 2.88 ± 0.14 mm lingual, with significant differences on both aspects ( p = 0.0043; p = 0.0029). The results suggest that greater thickness of peri-implant tissue can be expected when the triangular cervical implant design is used rather than the standard cervical design.

A Comparison of Burnout among Honors, Regular Education, and Special Education K-8 Teachers

ERIC Educational Resources Information Center

Sharpe, Christopher

2017-01-01

This study employed a quantitative, ex-post facto non-experimental design to examine the effect of whether teaching honors, regular, or special education classes in either an elementary or middle school setting influenced the experience of teacher burnout. Participants included 69 teachers from two counties in a Southern state. The study survey…

Informal Learning: Student Achievement and Motivation in Science through Museum-Based Learning

ERIC Educational Resources Information Center

Holmes, Julie A.

2011-01-01

This study examined changes in student motivation and achievement in science during a visit to a university children's science museum. The study was based on the pretest-posttest control comparison group design with four treatment groups: control, exhibit, lesson and exhibit/lesson. The sample consisted of 228 sixth-grade students from a Louisiana…

Effects of irrigation on sorghum forage yield and quality in the central sands region of Wisconsin

USDA-ARS?s Scientific Manuscript database

A study was conducted to assess effects of irrigation on yield and quality of photoperiod sensitive (PS) and non-PS forage sorghum, sorghum-sudangrass, and sudangrass in comparison to corn in central Wisconsin. The study was a strip-plot design with a 5 x 8 factorial arrangement of treatments. Five ...

Facebook Enhanced College Courses and the Impact of Personality on Sense of Classroom Community

ERIC Educational Resources Information Center

Barczyk, Casimir C.; Duncan, Doris G.

2017-01-01

The impact of personality type on students' sense of classroom connectedness was examined in a study of university-level business courses that used Facebook to enhance classroom learning. The study was conducted using an independent measures static group comparison research design. Nearly 600 students registered in six different business courses…

Modeling Complex Marine Ecosystems: An Investigation of Two Teaching Approaches with Fifth Graders

ERIC Educational Resources Information Center

Papaevripidou, M.; Constantinou, C. P.; Zacharia, Z. C.

2007-01-01

This study investigated acquisition and transfer of the modeling ability of fifth graders in various domains. Teaching interventions concentrated on the topic of marine ecosystems either through a modeling-based approach or a worksheet-based approach. A quasi-experimental (pre-post comparison study) design was used. The control group (n = 17)…

Students' Conceptual Change in Electricity and Magnetism Using Simulations: A Comparison of Cognitive Perturbation and Cognitive Conflict

ERIC Educational Resources Information Center

Dega, Bekele Gashe; Kriek, Jeanne; Mogese, Temesgen Fereja

2013-01-01

The purpose of this study was to investigate Ethiopian physics undergraduate students' conceptual change in the concepts of electric potential and energy (EPE) and electromagnetic induction (EMI). A quasi-experimental design was used to study the effect of cognitive perturbation using physics interactive simulations (CPS) in relation to cognitive…

A Comparison of Low Performing Students' Achievements in Factoring Cubic Polynomials Using Three Different Strategies

ERIC Educational Resources Information Center

Ogbonnaya, Ugorji I.; Mogari, David L.; Machisi, Eric

2013-01-01

In this study, repeated measures design was employed to compare low performing students' achievements in factoring cubic polynomials using three strategies. Twenty-five low-performing Grade 12 students from a secondary school in Limpopo province took part in the study. Data was collected using achievement test and was analysed using repeated…

A Comparison of Prompting Strategies to Teach Intraverbals to an Adolescent with Down Syndrome

ERIC Educational Resources Information Center

Wallace, Abigail M.; Bechtel, D. Reed; Heatter, Sue; Barry, Leasha M.

2016-01-01

Ingvarsson and Hollobaugh (2011) investigated tact- or echoic-to-intraverbal transfer of stimulus control to "wh" questions for three preschool-aged boys with autism. The current study was a systematic replication of this study with an adolescent girl with Down syndrome. A multi-element design was used to compare the effectiveness and…

Learning Biology through Innovative Curricula: A Comparison of Game- and Nongame-Based Approaches

ERIC Educational Resources Information Center

Sadler, Troy D.; Romine, William L.; Menon, Deepika; Ferdig, Richard E.; Annetta, Leonard

2015-01-01

This study explored student learning in the context of innovative biotechnology curricula and the effects of gaming as a central element of the learning experience. The quasi-experimentally designed study compared learning outcomes between two curricular approaches: One built around a computer-based game, and the other built around a narrative…

Impact of Baltimore Healthy Eating Zones: An Environmental Intervention to Improve Diet among African American Youth

ERIC Educational Resources Information Center

Shin, Ahyoung; Surkan, Pamela J.; Coutinho, Anastasia J.; Suratkar, Sonali R.; Campbell, Rebecca K.; Rowan, Megan; Sharma, Sangita; Dennisuk, Lauren A.; Karlsen, Micaela; Gass, Anthony; Gittelsohn, Joel

2015-01-01

This study assessed the impact of a youth-targeted multilevel nutrition intervention in Baltimore City. The study used a clustered randomized design in which 7 recreation centers and 21 corner stores received interventions and 7 additional recreation centers served as comparison. The 8-month intervention aimed to increase availability and…

Racial Differences in Retention in Residential Substance Abuse Treatment: The Impact on African American Men

ERIC Educational Resources Information Center

Cooper, R. Lyle; MacMaster, Samuel; Rasch, Randolph

2010-01-01

Purpose: This study employed a static group comparison design with 106 men in residential treatment to examine the relationship of race to treatment retention. Methods: A retrospective analysis of retention, by race, including survival analysis, was undertaken. Results: Findings from the study indicated that (a) Caucasian men complete treatment…

A FIELD STUDY TO COMPARE PERFORMANCE OF STAINLESS STEEL RESEARCH MONITORING WELLS WITH EXISTING ON-FARM DRINKING WATER WELLS IN MEASURING PESTICIDE AND NITRATE CONCENTRATIONS

EPA Science Inventory

Existing drinking wells are widely used for the collection of ground water samples to evaluate chemical contamination. A well comparison study was conducted to compare pesticide and nitrate-N data from specially designed stainless steel research monitoring wells with data from ne...

Synthesis of Single-Case Experimental Data: A Comparison of Alternative Multilevel Approaches

ERIC Educational Resources Information Center

Ferron, John; Van den Noortgate, Wim; Beretvas, Tasha; Moeyaert, Mariola; Ugille, Maaike; Petit-Bois, Merlande; Baek, Eun Kyeng

2013-01-01

Single-case or single-subject experimental designs (SSED) are used to evaluate the effect of one or more treatments on a single case. Although SSED studies are growing in popularity, the results are in theory case-specific. One systematic and statistical approach for combining single-case data within and across studies is multilevel modeling. The…

A Comparison of Model-Based and Design-Based Impact Evaluations of Interventions in Developing Countries

ERIC Educational Resources Information Center

Hansen, Henrik; Klejnstrup, Ninja Ritter; Andersen, Ole Winckler

2013-01-01

There is a long-standing debate as to whether nonexperimental estimators of causal effects of social programs can overcome selection bias. Most existing reviews either are inconclusive or point to significant selection biases in nonexperimental studies. However, many of the reviews, the so-called "between-studies," do not make direct…

Analyses of Eighth Grade Math Texts and Achievement (Evaluation Report). What Works Clearinghouse Detailed Study Report

ERIC Educational Resources Information Center

What Works Clearinghouse, 2005

2005-01-01

This evaluation was designed to compare student achievement scores of students enrolled in Saxon Algebra 1/2 classrooms (intervention group) with students enrolled in Scott-Foresman Mathematics classrooms (comparison group). Crawford and Raia conducted three analyses, but this study report focuses on the strongest analysis of the three and…

Case study comparison of two pellet heating facilities in southeastern Alaska

Treesearch

David Nicholls; Allen Brackley; Robert Deering; Daniel Parrent; Brian Kleinhenz; Craig. Moore

2016-01-01

Over the past decade, wood-energy use in Alaska has grown dramatically. Since 2000, several dozen new wood-energy installations have been established, with numerous others in the design or construction phase. This case study report compares two wood-pellet heating systems in Juneau, Alaska. The Tlingit-Haida Regional Housing Authority, a native housing authority that...

The Impact of Problem-Based Learning on Iranian EFL Learners' Speaking Proficiency

ERIC Educational Resources Information Center

Ansarian, Loghman; Adlipour, Ali Akbar; Saber, Mehrnoush Akhavan; Shafiei, Elmira

2016-01-01

The study investigated the effect of problem-based learning through cognition-based tasks on speaking proficiency of Iranian intermediate EFL learners in comparison to the effect of objective-based tasks. To this end, a true experimental research design was employed. Ninety five (N = 95) language learners studying at a language institute in the…

Effect of Instructional Strategy on Critical Thinking and Content Knowledge: Using Problem-Based Learning in the Secondary Classroom

ERIC Educational Resources Information Center

Burris, Scott; Garton, Bryan L.

2007-01-01

The purpose of the study was to determine the effect of problem-based learning (PBL) on critical thinking ability and content knowledge among selected secondary agriculture students in Missouri. The study employed a quasi-experimental, non-equivalent comparison group design. The treatment consisted of two instructional strategies: problem-based…

Female Sex Offenders: Exploring Issues of Personality, Trauma, and Cognitive Distortions

ERIC Educational Resources Information Center

Strickland, Susan M.

2008-01-01

Few studies have investigated the characteristics of female sex offenders and factors and/or causes of female deviance. Research to date has been descriptive in nature, with few comparison studies. Using a correlational design and three valid instruments, female sexual offenders and a matched group of female nonsexual offenders are compared in the…

A COMPARISON OF MATHEMATICS PROGRAMS FOR ABLE JUNIOR HIGH SCHOOL STUDENTS, VOLUME 1 - FINAL REPORT.

ERIC Educational Resources Information Center

GOLDBERG, MIRIAM L.; AND OTHERS

THE TALENTED YOUTH PROJECT (TYP) MATHEMATICS STUDY WAS DESIGNED AS A STUDY TO COMPARE THE EFFECTIVENESS OF VARIOUS CURRICULUM PATTERNS AND PRACTICES IN MATHEMATICS EDUCATION CURRENTLY USED WITH ACADEMICALLY TALENTED JUNIOR HIGH SCHOOL STUDENTS. THE SAMPLE CONSISTED OF 51 CLASSES AND 6 MATHEMATICS PROGRAMS. THE LORGE-THORNDIKE VERBAL INTELLIGENCE…

Using Participant Data to Extend the Evidence Base for Intensive Behavioral Intervention for Children with Autism

ERIC Educational Resources Information Center

Eldevik, Sigmund; Hastings, Richard P.; Hughes, J. Carl; Jahr, Erik; Eikeseth, Svein; Cross, Scott

2010-01-01

We gathered individual participant data from 16 group design studies on behavioral intervention for children with autism. In these studies, 309 children received behavioral intervention, 39 received comparison interventions, and 105 were in a control group. More children who underwent behavioral intervention achieved reliable change in IQ (29.8%)…

A Comparison of Biologic Content in Three Elementary-School Science Curriculum Projects: ESS, S-APA, SCIS

ERIC Educational Resources Information Center

Simpson, Ronald D.

1974-01-01

Three elementary school science curriculum projects, Elementary Science Study (ESS), Science - A Process Approach (S-APA), and Science Curriculum Improvement Study (SCIS), are compared concerning the biologic content each project contains. The reviewer found a lack of activities designed to represent functions at the cellular level. Two projects…

The Effects of Team-Based Learning on Social Studies Knowledge Acquisition in High School

ERIC Educational Resources Information Center

Wanzek, Jeanne; Vaughn, Sharon; Kent, Shawn C.; Swanson, Elizabeth A.; Roberts, Greg; Haynes, Martha; Fall, Anna-Mária; Stillman-Spisak, Stephanie J.; Solis, Michael

2014-01-01

This randomized control trial examined the efficacy of team-based learning implemented within 11th-grade social studies classes. A randomized blocked design was implemented with 26 classes randomly assigned to treatment or comparison. In the treatment classes teachers implemented team-based learning practices to support students in engaging in…

Age-Related Differences in Responses to a Physician's Persuasive Message in an Interpersonal Setting.

ERIC Educational Resources Information Center

Keller, Jo

A study investigated whether older persons as a group are generally more persuaded by high authority figures than are younger persons. The study employed a design that allowed for extensive comparisons among subjects of different ages in terms of their willingness to be persuaded by physicians in interpersonal situations. One hundred-twenty…

Design criteria for maglev structures

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

Sandberg, H.R.; Williams, J.R.

1997-05-01

Maglev systems represent an entirely new concept in transportation. They will not operate on nor share the right-of-way with any other system. It is important, therefore, that the guideways be designed and constructed so as to be economical, constructable, durable, adaptable, reliable, and readily maintained. Comparisons should be made with the current transportation systems, especially highways and railroads. Since most of the guideway will be elevated, the comparison should be with the bridges. The object of the comparisons should be to avoid the shortcomings of the other systems while building on their strengths. This paper develops in some detail designmore » and construction criteria that will ensure a good, long-lived performance of the maglev guideway. The importance of beauty should have a low priority in comparison to the other design criteria. Clean, simple details meeting other criteria will ensure an acceptable appearance. These criteria were used in evaluating the four maglev concepts developed for the National Maglev Initiative.« less

Development and fabrication of a graphite polyimide box beam

NASA Technical Reports Server (NTRS)

Nadler, M. A.; Darms, F. J.

1972-01-01

The state-of-the-art of graphite/polyimide structures was evaluated and key design and fabrication issues to be considered in future hardware programs are defined. The fabrication and testing at 500 F of a graphite/polyimide center wing box beam using OV-10A aircraft criteria was accomplished. The baseline design of this box was developed in a series of studies of other advanced composite materials: glass/epoxy, boron/epoxy, and boron/polyimide. The use of this basic design permits ready comparison of the performance of graphite/polyimide with these materials. Modifications to the baseline composite design were made only in those areas effected by the change of materials. Processing studies of graphite fiber polyimide resins systems resulted in the selection of a Modmor II/Gemon L material.

An experimental study of pressures on 60 deg Delta wings with leading edge vortex flaps

NASA Technical Reports Server (NTRS)

Marchman, J. F., III; Terry, J. E.; Donatelli, D. A.

1983-01-01

An experimental study was conducted in the Virginia Tech Stability Wind Tunnel to determine surface pressures over a 60 deg sweep delta wing with three vortex flap designs. Extensive pressure data was collected to provide a base data set for comparison with computational design codes and to allow a better understanding of the flow over vortex flaps. The results indicated that vortex flaps can be designed which will contain the leading edge vortex with no spillage onto the wing upper surface. However, the tests also showed that flaps designed without accounting for flap thickness will not be optimum and the result can be oversized flaps, early flap vortex reattachment and a second separation and vortex at the wing/flap hinge line.

Study of crash energy absorption characteristics of inversion tube on passenger vehicle

NASA Astrophysics Data System (ADS)

Liu, Jiandong; Liu, Tao; Yao, Shengjie; Zhao, Rutao

2017-09-01

This article studied the energy absorption characteristics of the inversion tube and acquired the inversion tube design key dimensions under theoretical conditions by performing formula derivation in the quasi-static and dynamic state based on the working principle of the inversion tube: free inversion. The article further adopted HyperMesh and LS-Dyna to perform simulation and compared the simulation result with the theoretical calculating value for comparison. The design was applied in the full-vehicle model to perform 50km/h front fullwidth crash simulation. The findings showed that the deformation mode of the inversion tube in the full-vehicle crash was consistent with the design mode, and the inversion tube absorbed 33.0% of total energy, thereby conforming to the vehicle safety design requirements.

Evaluation of FFTF fuel pin design procedure vis-a-vis steady state irradiation performance in EBR II

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

Jackson, R.J.

1976-11-01

The FFTF fuel pin design analysis is shown to be conservative through comparison with pin irradiation experience in EBR-II. This comparison shows that the actual lifetimes of EBR-II fuel pins are either greater than 80,000 MWd/MTM or greater than the calculated allowable lifetimes based on thermal creep strain.

Why an Active Comparison Group Makes a Difference and What to Do about It

ERIC Educational Resources Information Center

Datta, Lois-ellin

2007-01-01

The Randomized Control Trials (RCT) design and its quasi-experimental kissing cousin, the Comparison Group Trials (CGT), are golden to some and not even silver to others. At the center of the affection, at the vortex of the discomfort, are beliefs about what it takes to establish causality. These designs are considered primarily when the purpose…

Statistical Power for the Comparative Regression Discontinuity Design With a Pretest No-Treatment Control Function: Theory and Evidence From the National Head Start Impact Study.

PubMed

Tang, Yang; Cook, Thomas D

2018-01-01

The basic regression discontinuity design (RDD) has less statistical power than a randomized control trial (RCT) with the same sample size. Adding a no-treatment comparison function to the basic RDD creates a comparative RDD (CRD); and when this function comes from the pretest value of the study outcome, a CRD-Pre design results. We use a within-study comparison (WSC) to examine the power of CRD-Pre relative to both basic RDD and RCT. We first build the theoretical foundation for power in CRD-Pre, then derive the relevant variance formulae, and finally compare them to the theoretical RCT variance. We conclude from this theoretical part of this article that (1) CRD-Pre's power gain depends on the partial correlation between the pretest and posttest measures after conditioning on the assignment variable, (2) CRD-Pre is less responsive than basic RDD to how the assignment variable is distributed and where the cutoff is located, and (3) under a variety of conditions, the efficiency of CRD-Pre is very close to that of the RCT. Data from the National Head Start Impact Study are then used to construct RCT, RDD, and CRD-Pre designs and to compare their power. The empirical results indicate (1) a high level of correspondence between the predicted and obtained power results for RDD and CRD-Pre relative to the RCT, and (2) power levels in CRD-Pre and RCT that are very close. The study is unique among WSCs for its focus on the correspondence between RCT and observational study standard errors rather than means.

Using Virtual Reality and Videogames for Traumatic Brain Injury Rehabilitation: A Structured Literature Review.

PubMed

Pietrzak, Eva; Pullman, Stephen; McGuire, Annabel

2014-08-01

This article reviews the available literature about the use of novel methods of rehabilitation using virtual reality interventions for people living with posttraumatic brain injuries. The MEDLINE, EMBASE, SCOPUS, and Cochrane Library databases were searched using the terms "virtual reality" OR "video games" AND "traumatic brain injury." Included studies investigated therapeutic use of virtual reality in adults with a brain trauma resulting from acquired closed head injury, reported outcomes that included measures of motor or cognitive functionality, and were published in a peer-reviewed journal written in English. Eighteen articles fulfilled inclusion criteria. Eight were case studies, five studies had a quasi-experimental design with a pre-post comparison, and five were pilot randomized control trials or comparative studies. The virtual reality systems used were commercial or custom designed for the study and ranged from expensive, fully immersive systems to cheap online games or videogames. In before-after comparisons, improvements in balance were seen in four case studies and two small randomized control trials. Between-group comparisons in these randomized control trials showed no difference between virtual reality and traditional therapy. Post-training improvements were also seen for upper extremity functions (five small studies) and for various cognitive function measures (four case studies and one pilot randomized control trial). Attitudes of participants toward virtual reality interventions was more positive than for traditional therapy (three studies). The evidence that the use of virtual reality in rehabilitation of traumatic brain injury improves motor and cognitive functionality is currently very limited. However, this approach has the potential to provide alternative, possibly more affordable and available rehabilitation therapy for traumatic brain injury in settings where access to therapy is limited by geographical or financial constraints.

Behavioral headache research: methodologic considerations and research design alternatives.

PubMed

Hursey, Karl G; Rains, Jeanetta C; Penzien, Donald B; Nash, Justin M; Nicholson, Robert A

2005-05-01

Behavioral headache treatments have garnered solid empirical support in recent years, but there is substantial opportunity to strengthen the next generation of studies with improved methods and consistency across studies. Recently, Guidelines for Trials of Behavioral Treatments for Recurrent Headache were published to facilitate the production of high-quality research. The present article compliments the guidelines with a discussion of methodologic and research design considerations. Since there is no research design that is applicable in every situation, selecting an appropriate research design is fundamental to producing meaningful results. Investigators in behavioral headache and other areas of research consider the developmental phase of the research, the principle objectives of the project, and the sources of error or alternative interpretations in selecting a design. Phases of clinical trials typically include pilot studies, efficacy studies, and effectiveness studies. These trials may be categorized as primarily pragmatic or explanatory. The most appropriate research designs for these different phases and different objectives vary on such characteristics as sample size and assignment to condition, types of control conditions, periods or frequency of measurement, and the dimensions along which comparisons are made. A research design also must fit within constraints on available resources. There are a large number of potential research designs that can be used and considering these characteristics allows selection of appropriate research designs.

Headspace profiling of cocaine samples for intelligence purposes.

PubMed

Dujourdy, Laurence; Besacier, Fabrice

2008-08-06

A method for determination of residual solvents in illicit hydrochloride cocaine samples using static headspace-gas chromatography (HS-GC) associated with a storage computerized procedure is described for the profiling and comparison of seizures. The system involves a gas chromatographic separation of 18 occluded solvents followed by fully automatic data analysis and transfer to a PHP/MySQL database. First, a fractional factorial design was used to evaluate the main effects of some critical method parameters (salt choice, vial agitation intensity, oven temperature, pressurization and loop equilibration) on the results with a minimum of experiments. The method was then validated for tactical intelligence purposes (batch comparison) via several studies: selection of solvents and mathematical comparison tool, reproducibility and "cutting" influence studies. The decision threshold to determine the similarity of two samples was set and false positives and negatives evaluated. Finally, application of the method to distinguish geographical origins is discussed.

Physician Perceptions of Performance Feedback in a Quality Improvement Activity.

PubMed

Eden, Aimee R; Hansen, Elizabeth; Hagen, Michael D; Peterson, Lars E

Physician performance and peer comparison feedback can affect physician care quality and patient outcomes. This study aimed to understand family physician perspectives of the value of performance feedback in quality improvement (QI) activities. This study analyzed American Board of Family Medicine open-ended survey data collected between 2004 and 2014 from physicians who completed a QI module that provided pre- and post-QI project individual performance data and peer comparisons. Physicians made 3480 comments in response to a question about this performance feedback, which were generally positive in nature (86%). Main themes that emerged were importance of accurate feedback data, enhanced detail in the content of feedback, and ability to customize peer comparison groups to compare performance to peers with similar patient populations or practice characteristics. Meaningful and tailored performance feedback may be an important tool for physicians to improve their care quality and should be considered an integral part of QI project design.

Dance Education Action Research: A Twin Study

ERIC Educational Resources Information Center

Giguere, Miriam

2015-01-01

In this article, the author compares the practices, philosophy, and history of action research, also known as participatory action research, to the purposes and practices of dance education. The comparison yields connections in four categories, enhancing self-reflective teaching and curriculum design, taking responsibility for teaching outcomes,…

A modal comparison of domestic freight transportation effects on the general public

DOT National Transportation Integrated Search

2007-12-01

Initially, this study was designed to focus on certain segments of the IWWS. However, for : certain types of analyses, it is not feasible to segregate components of the system, i.e., river segments, rail segments, etc. In these cases, the analysis is...

A comparison of the vigilance performance of men and women using a simulated radar task.

DOT National Transportation Integrated Search

1978-03-01

The present study examined the question of possible sex differences in the ability to sustain attention to a complex monitoring task requiring only a detection response to critical stimulus changes. The visual display was designed to approximate a fu...

Handbook for the Emergence of Civilization.

ERIC Educational Resources Information Center

O'Neill, David; And Others

This handbook, prepared through the Anthropology Curriculum Study Project in Chicago, Illinois, is designed to accompany the secondary level textbook, "The Emergence of Civilization" (SO 012 148) written in 1964. The textbook emphasizes the comparison of the patterns of culture change which resulted in complex societies (civilizations)…

A Large-Scale Evaluation of an Intelligent Discovery World: Smithtown.

ERIC Educational Resources Information Center

Shute, Valerie J.; Glaser, Robert

1990-01-01

Presents an evaluation of "Smithtown," an intelligent tutoring system designed to teach inductive inquiry skills and principles of basic microeconomics. Two studies of individual differences in learning are described, including a comparison of knowledge acquisition with traditional instruction; hypotheses tested are discussed; and the…

Using the Microcomputer to Study the Anatomy of Revolution.

ERIC Educational Resources Information Center

Rothman, Mark

1982-01-01

Describes computer program designed to enable students to analyze process of political revolution by generating graphs for comparisons of such factors as violence, economic instability, and political instability. Student activities, abilities, and reactions, and teacher involvement are noted. Sources concerning revolution, the French Revolution,…

Safety comparison of roadway design elements on urban collectors with access : final report, April 2009.

DOT National Transportation Integrated Search

2009-04-01

The main goal of this study identified by NJDOT can be defined as the quantification of the effects of : management treatments on roadway operations and safety on urban collectors with access. : Since, urban collector road runs through highly d...

Motivational Enhancement Career Intervention for Youth with Disabilities

ERIC Educational Resources Information Center

Sheftel, Anya; Lindstrom, Lauren; McWhirter, Benedict

2014-01-01

Youth with disabilities face both internal and external barriers to career development and often experience poor post school outcomes in comparison to their nondisabled peers. The purpose of this study was to design, implement, and evaluate a motivational interviewing-based group career intervention--Motivational Enhancement Group Intervention…

Teachers' and Pupils' Definitions of Bullying

ERIC Educational Resources Information Center

Naylor, Paul; Cowie, Helen; Cossin, Fabienne; de Bettencourt, Rita; Lemme, Francesca

2006-01-01

Background: Comparison of teachers' and pupils' definitions of bullying is important for considering the implications for reports of its incidence in schools, for the study of developmental trends in children's and adolescents' perceptions of the phenomenon and for evaluating the effectiveness of interventions designed to combat bullying. Aims: To…

Core ADHD Symptom Improvement with Atomoxetine versus Methylphenidate: A Direct Comparison Meta-Analysis

ERIC Educational Resources Information Center

Hazell, Philip L.; Kohn, Michael R.; Dickson, Ruth; Walton, Richard J.; Granger, Renee E.; van Wyk, Gregory W.

2011-01-01

Objective: Previous studies comparing atomoxetine and methylphenidate to treat ADHD symptoms have been equivocal. This noninferiority meta-analysis compared core ADHD symptom response between atomoxetine and methylphenidate in children and adolescents. Method: Selection criteria included randomized, controlled design; duration 6 weeks; and…

Southwest Cardiovascular Curriculum Project: Study Findings for American Indian Elementary Students.

ERIC Educational Resources Information Center

Davis, Sally M.; And Others

1995-01-01

This article describes the Southwestern Cardiovascular Curriculum, a school-based, culturally relevant curriculum designed to prevent tobacco use and promote a good diet. Comparisons of American Indian students in participating and nonparticipating schools indicated that participants had significant increases in knowledge, better diets, increased…

Kinematic design considerations for minimally invasive surgical robots: an overview.

PubMed

Kuo, Chin-Hsing; Dai, Jian S; Dasgupta, Prokar

2012-06-01

Kinematic design is a predominant phase in the design of robotic manipulators for minimally invasive surgery (MIS). However, an extensive overview of the kinematic design issues for MIS robots is not yet available to both mechanisms and robotics communities. Hundreds of archival reports and articles on robotic systems for MIS are reviewed and studied. In particular, the kinematic design considerations and mechanism development described in the literature for existing robots are focused on. The general kinematic design goals, design requirements, and design preferences for MIS robots are defined. An MIS-specialized mechanism, namely the remote center-of-motion (RCM) mechanism, is revisited and studied. Accordingly, based on the RCM mechanism types, a classification for MIS robots is provided. A comparison between eight different RCM types is given. Finally, several open challenges for the kinematic design of MIS robotic manipulators are discussed. This work provides a detailed survey of the kinematic design of MIS robots, addresses the research opportunity in MIS robots for kinematicians, and clarifies the kinematic point of view to MIS robots as a reference for the medical community. Copyright © 2012 John Wiley & Sons, Ltd.

Mirror fusion propulsion system: A performance comparison with alternate propulsion systems for the manned Mars Mission

NASA Technical Reports Server (NTRS)

Schulze, Norman R.; Carpenter, Scott A.; Deveny, Marc E.; Oconnell, T.

1993-01-01

The performance characteristics of several propulsion technologies applied to piloted Mars missions are compared. The characteristics that are compared are Initial Mass in Low Earth Orbit (IMLEO), mission flexibility, and flight times. The propulsion systems being compared are both demonstrated and envisioned: Chemical (or Cryogenic), Nuclear Thermal Rocket (NTR) solid core, NTR gas core, Nuclear Electric Propulsion (NEP), and a mirror fusion space propulsion system. The proposed magnetic mirror fusion reactor, known as the Mirror Fusion Propulsion System (MFPS), is described. The description is an overview of a design study that was conducted to convert a mirror reactor experiment at Lawrence Livermore National Lab (LLNL) into a viable space propulsion system. Design principles geared towards minimizing mass and maximizing power available for thrust are identified and applied to the LLNL reactor design, resulting in the MFPS. The MFPS' design evolution, reactor and fuel choices, and system configuration are described. Results of the performance comparison shows that the MFPS minimizes flight time to 60 to 90 days for flights to Mars while allowing continuous return-home capability while at Mars. Total MFPS IMLEO including propellant and payloads is kept to about 1,000 metric tons.

Mirror fusion propulsion system - A performance comparison with alternate propulsion systems for the manned Mars mission

NASA Technical Reports Server (NTRS)

Deveny, M.; Carpenter, S.; O'Connell, T.; Schulze, N.

1993-01-01

The performance characteristics of several propulsion technologies applied to piloted Mars missions are compared. The characteristics that are compared are Initial Mass in Low Earth Orbit (IMLEO), mission flexibility, and flight times. The propulsion systems being compared are both demonstrated and envisioned: Chemical (or Cryogenic), Nuclear Thermal Rocket (NTR) solid core, NTR gas core, Nuclear Electric Propulsion (NEP), and a mirror fusion space propulsion system. The proposed magnetic mirror fusion reactor, known as the Mirror Fusion Propulsion System (MFPS), is described. The description is an overview of a design study that was conducted to convert a mirror reactor experiment at Lawrence Livermore National Lab (LLNL) into a viable space propulsion system. Design principles geared towards minimizing mass and maximizing power available for thrust are identified and applied to the LLNL reactor design, resulting in the MFPS. The MFPS' design evolution, reactor and fuel choices, and system configuration are described. Results of the performance comparison shows that the MFPS minimizes flight time to 60 to 90 days for flights to Mars while allowing continuous return-home capability while at Mars. Total MFPS IMLEO including propellant and payloads is kept to about 1,000 metric tons.

Eating disorders in college men.

PubMed

Olivardia, R; Pope, H G; Mangweth, B; Hudson, J I

1995-09-01

This study was designed to assess the characteristics of men with eating disorders in the community. The authors recruited 25 men meeting DSM-IV criteria for eating disorders and 25 comparison men through advertisements in college newspapers. A second comparison group comprised 33 women with bulimia nervosa who were recruited and interviewed with virtually identical methods. The men with eating disorders closely resembled the women with eating disorders but differed sharply from the comparison men in phenomenology of illness, rates of comorbid psychiatric disorders, and dissatisfaction with body image. Homosexuality did not appear to be a common feature of men with eating disorders in the community. Childhood physical and sexual abuse appeared slightly more common among the eating-disordered men than among the comparison men. Eating disorders, although less common in men than in women, appear to display strikingly similar features in affected individuals of the two genders.

Friction characteristics of trocars in laparoscopic surgery.

PubMed

Alazmani, Ali; Roshan, Rupesh; Jayne, David G; Neville, Anne; Culmer, Peter

2015-04-01

This article investigates the friction characteristics of the instrument-trocar interface in laparoscopic surgery for varying linear instrument velocities, trocar seal design and material, and trocar tilt. Furthermore, the effect of applying lubrication at the instrument-trocar seal interface on friction was studied. A friction testing apparatus was designed and built to characterise the resistance force at the instrument-trocar interface as a function of the instrument's linear movement in the 12-mm trocar (at constant velocity) for different design, seal material, and angle of tilt. The resistance force depended on the trocar seal design and material properties, specifically surface roughness, elasticity, hardness, the direction of movement, and the instrument linear velocity, and varied between 0.25 and 8 N. Lubricating the shaft with silicone oil reduced the peak resistance force by 75% for all trocars and eliminated the stick-slip phenomenon evident in non-lubricated cases. The magnitude of fluctuation in resistance force depends on the trocar design and is attributed to stick-slip of the sealing mechanism and is generally higher during retraction in comparison to insertion. Trocars that have an inlet seal made of rubber/polyurethane showed higher resistance forces during retraction. Use of a lubricant significantly reduced frictional effects. Comparisons of the investigated trocars indicate that a low friction port, providing the surgeon with improved haptic feedback, can be designed by improving the tribological properties of the trocar seal interface. © IMechE 2015.

Design of a Steerable Two-beam System for Simultaneous On- and Off-axis Imaging with GUFI

NASA Astrophysics Data System (ADS)

Chambers, V. J.; Butler, R. F.; Goncharov, A. V.

2008-02-01

The GUFI (Galway Ultra Fast Imager) has been primarily developed for high throughput differential photometry, in order to study variability in challenging circumstances, such as near bright sources or within crowded fields. The instrument features a low light level charged coupled device (L3-CCD) that enhances detector speed and sensitivity but only covers small fields of view. This presents limitations on possible science targets when suitable differential photometry comparison stars are not in the immediate vicinity of the target. Conventional solutions for imaging larger portions of sky without sacrificing SNR include telescope focal reduction methods and large arrays of CCDs. Our alternative solution entails a two-path, `outrigger' optical design to image target and comparison stars separately. This new approach allows detection of variable targets that formerly were not reachable with smaller-field detectors. The mechanical design was originally generated with AutoCAD® drafting software before being compiled in, and vetted with an OSLO® optical design package. Through filters B, V and I, the limiting design aberration was chromatic focal shift that appeared most severe in the B-filter's bandpass range. However, the degree of image blurring caused by this aberration and others did not exceed the scale of that already produced by atmospheric turbulence. For each bandpass, the model's imaging performance met and exceeded expectations set by all design constraints.

What works with worked examples: Extending self-explanation and analogical comparison to synthesis problems

NASA Astrophysics Data System (ADS)

Badeau, Ryan; White, Daniel R.; Ibrahim, Bashirah; Ding, Lin; Heckler, Andrew F.

2017-12-01

The ability to solve physics problems that require multiple concepts from across the physics curriculum—"synthesis" problems—is often a goal of physics instruction. Three experiments were designed to evaluate the effectiveness of two instructional methods employing worked examples on student performance with synthesis problems; these instructional techniques, analogical comparison and self-explanation, have previously been studied primarily in the context of single-concept problems. Across three experiments with students from introductory calculus-based physics courses, both self-explanation and certain kinds of analogical comparison of worked examples significantly improved student performance on a target synthesis problem, with distinct improvements in recognition of the relevant concepts. More specifically, analogical comparison significantly improved student performance when the comparisons were invoked between worked synthesis examples. In contrast, similar comparisons between corresponding pairs of worked single-concept examples did not significantly improve performance. On a more complicated synthesis problem, self-explanation was significantly more effective than analogical comparison, potentially due to differences in how successfully students encoded the full structure of the worked examples. Finally, we find that the two techniques can be combined for additional benefit, with the trade-off of slightly more time on task.

A Comparison of Level of Discrimination Directed at Academic Staff in a Turkish and an Azerbaijani University

ERIC Educational Resources Information Center

Halici, Ali; Kasimoglu, Murat

2006-01-01

Purpose: The aim of this study is to understand the level of discrimination against academic staff in a Turkish and an Azerbaijani university. This research is the last stage of a four-stage study. Design/methodology/approach: In the first part of the study, the areas of discrimination in universities were determined using approaches related to…

Eye Health in New Zealand: A Study of Public Knowledge, Attitudes, and Practices Related to Eye Health and Disease

ERIC Educational Resources Information Center

Ahn, Mark J.; Frederikson, Lesley; Borman, Barry; Bednarek, Rebecca

2011-01-01

Purpose: This study seeks to measure the public knowledge, attitudes, and practices related to eye health and disease in New Zealand (NZ). Design/methodology/approach: A 22-item survey of 507 adults in NZ was conducted. The survey was developed using interviews and focus groups, as well as comparisons with other benchmark international studies.…

Comparison of Four Teacher Training Procedures in Achieving Teacher and Pupil "Translation" Behaviors in Secondary School Social Studies.

ERIC Educational Resources Information Center

Millett, Gregg B.

A study was designed to determine whether different training procedures could change specific behaviors of 39 intern teachers and their pupils in secondary school social studies classes. Interns were randomly assigned to four training groups each of which received typescripts from the 1953 McCarthy investigations which were to be used the next day…

Is Full-Day Kindergarten Worth It? an Academic Comparison of Full-Day and Half-Day Kindergarten Programs

ERIC Educational Resources Information Center

Romines, Robert A.

2012-01-01

The purpose of this study is to answer this question: Which is academically superior for young children, full-or half-day kindergarten? This inquiry-oriented case study was designed to compare and contrast students who attended half-day versus full-day kindergarten programs in a suburban public school district. The study is necessary because the…

Preliminary Sizing Study of Ares-I and Ares-V Liquid Hydrogen Tanks

NASA Technical Reports Server (NTRS)

Oliver, Stanley T.; Harper, David W.

2012-01-01

A preliminary sizing study of two cryogenic propellant tanks was performed using a FORTRAN optimization program to determine weight efficient orthogrid designs for the tank barrels sections only. Various tensile and compressive failure modes were considered, including general buckling of cylinders with a shell buckling knockdown factor. Eight independent combinations of three design requirements were also considered and their effects on the tanks weight. The approach was to investigate each design case with a variable shell buckling knockdown factor, determining the most weight efficient combination of orthogrid design parameters. Numerous optimization analyses were performed, and the results presented herein compare the effects of the different design requirements and shell buckling knockdown factor. Through a series of comparisons between design requirements or shell buckling knockdown factors, the relative change in overall tank barrel weights is shown. The findings indicate that the design requirements can substantually increase the tank weight while a less conservative shell buckling knockdown factor can modestly reduce the tank weight.

Design and development of a prototype wet oxidation system for the reclamation of water and the disposition of waste residues onboard space vehicles

NASA Technical Reports Server (NTRS)

Jagow, R. B.

1972-01-01

Laboratory investigations to define optimum process conditions for oxidation of fecal/urine slurries were conducted in a one-liter batch reactor. The results of these tests formed the basis for the design, fabrication, and testing of an initial prototype system, including a 100-hour design verification test. Areas of further development were identified during this test. Development of a high pressure slurry pump, materials corrosion studies, oxygen supply trade studies, comparison of salt removal water recovery devices, ammonia removal investigation, development of a solids grinder, reactor design studies and bearing life tests, and development of shutoff valves and a back pressure regulator were undertaken. The development work has progressed to the point where a prototype system suitable for manned chamber testing can be fabricated and tested with a high degree of confidence of success.

Design and analysis issues in quantitative proteomics studies.

PubMed

Karp, Natasha A; Lilley, Kathryn S

2007-09-01

Quantitative proteomics is the comparison of distinct proteomes which enables the identification of protein species which exhibit changes in expression or post-translational state in response to a given stimulus. Many different quantitative techniques are being utilized and generate large datasets. Independent of the technique used, these large datasets need robust data analysis to ensure valid conclusions are drawn from such studies. Approaches to address the problems that arise with large datasets are discussed to give insight into the types of statistical analyses of data appropriate for the various experimental strategies that can be employed by quantitative proteomic studies. This review also highlights the importance of employing a robust experimental design and highlights various issues surrounding the design of experiments. The concepts and examples discussed within will show how robust design and analysis will lead to confident results that will ensure quantitative proteomics delivers.

Multicriteria analysis of product operational effectiveness at design stages

NASA Astrophysics Data System (ADS)

Irzaev, G. Kh

2018-03-01

The multicriteria rapid assessment method of techno-economic parameters of new products is developed. It avoids expensive engineering changes during the operational stages through the analysis of external and internal factors at an early stage in the design that affect the maintainability and manufacturability of the product. The expert selection of the initial multitude of indicators from the five enlarged criteria groups and their subsequent pairwise comparison allow one to distinguish the complex compliance criteria of product design with the average and optimum values of the operational effectiveness. The values comparison provides an opportunity to decide on the continuation of the process for designing and preparation of the product manufacture.

Revisiting the Boeing B-47 and the Avro Vulcan with implications on aircraft design today

NASA Astrophysics Data System (ADS)

van Seeters, Philip A.

This project compares the cruise mission performance of the historic Boeing B-47 and Avro Vulcan. The author aims to demonstrate that despite superficial similarities, these aircraft perform quite differently away from their intended design points. The investigation uses computer aided design software, and an aircraft sizing program to generate digital models of both airplanes. Subsequent simulations of various missions quantify the performance mainly in terms of fuel efficiency, and productivity. Based on this comparison, the efforts conclude that these aircraft perform indeed differently, and that a performance comparison based on a design mission alone, is insufficient.

Conceptual design study of concentrator enhanced solar arrays for space applications Volume 2: Technical

NASA Technical Reports Server (NTRS)

1979-01-01

Concentrator concepts which utilize Kapton mirror material were evaluated and selected for solar array use due to their zero mass. All concepts considered employed thin silicon solar cells. Design requirements for the concentrator were: the cell temperature was not to exceed 150 C; the concentrators were to produce illumination of the array within 15% of being perfectly uniform; the concentrators were to operate while misaligned as much as 5 degrees with the solar axis. Concentrator designs along with mirror structure and configurations are discussed and comparisons are made for optimal space applications.

Three types of solid state remote power controllers

NASA Technical Reports Server (NTRS)

Baker, D. E.

1975-01-01

Three types of solid state Remote Power Controller (RPC) circuits for 120 Vdc spacecraft distribution systems have been developed and evaluated. Both current limiting and noncurrent limiting modes of overload protection were developed and were demonstrated to be feasible. A second generation of circuits was developed which offers comparable performance with substantially less cost and complexity. Electrical efficiency for both generations is 98.5 to 99%. This paper describes various aspects of the circuit design, trade-off studies, and experimental test results. Comparisons of design parameters, component requirements, and engineering model evaluations will emphasize the high efficiency and reliability of the designs.

Manufacturing cost/design trade-studies for flywheel

NASA Astrophysics Data System (ADS)

Noton, B. R.

1982-12-01

A procedure is described for enabling comparison of different flywheel designs based on both performance ratings, and manufacturing and inspection cost. Development of the methodology requires identification of all the steps in the manufacture and inspection of each design, the cost drivers, and the ground rules. A man-hour summary must also be provided. The approach to determine the recurring and nonrecurring manufacturing man-hours is presented. Cost drivers in composite manufacture are discussed as well as the approach to address cost driver data from industry. Some indications for cost driver data from industry. Some indications for cost reduction are included.

Economic comparison of fabric filters and electrostatic precipitators for particulate control on coal-fired utility boilers

NASA Technical Reports Server (NTRS)

Cukor, P. M.; Chapman, R. A.

1978-01-01

The uncertainties and associated costs involved in selecting and designing a particulate control device to meet California's air emission regulations are considered. The basic operating principles of electrostatic precipitators and fabric filters are discussed, and design parameters are identified. The size and resulting cost of the control device as a function of design parameters is illustrated by a case study for an 800 MW coal-fired fired utility boiler burning a typical southwestern subbituminous coal. The cost of selecting an undersized particulate control device is compared with the cost of selecting an oversized device.

Habitat Utilization Assessment - Building in Behaviors

NASA Technical Reports Server (NTRS)

Whitmore, Mihriban; Blume, Jennifer

2004-01-01

Habitability, and the associated architectural and design attributes of an environment, is a powerful performance shaping factor. By identifying how inhabitants use an area, we can draw conclusions about what design or architectural attributes cause what behaviors and systematically design in desired human performance. We are analyzing how a crew uses a long duration habitat and work environment during a four-day underwater mission and identifying certain architectural and design attributes that are related to, and potential enablers of, certain crew behaviors. By identifying how inhabitants use the habitat, we can draw conclusions about what habitability attributes cause what behaviors and systematically design in desired human performance (applicable to NASA's Bioastronautics Human Behavior and Performance Critical Path Roadmap question 6.12). This assessment replicates a methodology reported in a chapter titled "Sociokinetic Analysis as a Tool for Optimization of Environmental Design" by C. Adams.' That study collected video imagery of certain areas of a closed habitat during a 91 day test and from that data calculated time spent in different volumes during the mission, and characterized the behaviors occurring in certain habitat volumes thus concluding various rules for design of such habitats. This study assesses the utilization of the Aquarius Habitat, an underwater station, which will support six Aquanauts for a fourteen-day mission during which the crew will perform specific scientific and engineering studies. Video is recorded for long uninterrupted periods of time during the mission and from that data the time spent in each area is calculated. In addition, qualitative and descriptive analysis of the types of behaviors in each area is performed with the purpose of identifying any behaviors that are not typical of a certain area. If a participant uses an area in a way different from expected, a subsequent analysis of the features of that area may result in conclusions of performance shaping factors. With the addition of this study, we can make comparisons between the two different habitats and begin drawing correlation judgments about design features and behavior. Ideally, this methodology should be repeated in additional Aquarius missions and other analog environments because the real information will come from comparisons between habitats.

Nanomedicines for Inflammatory Arthritis: Head-To-Head Comparison of Glucocorticoid-Containing Polymers, Micelles and Liposomes

PubMed Central

Crielaard, Bart J.; Dusad, Anand; Lele, Subodh M.; Rijcken, Cristianne J. F.; Metselaar, Josbert M; Kostková, Hana; Etrych, Tomáš; Ulbrich, Karel; Kiessling, Fabian; Mikuls, Ted R.; Hennink, Wim E.; Storm, Gert; Lammers, Twan; Wang, Dong

2014-01-01

As an emerging research direction, nanomedicine has been increasingly utilized to treat inflammatory diseases. In this head-to-head comparison study, four established nanomedicine formulations of dexamethasone, including liposomes (L-Dex), core-crosslinked micelles (M-Dex), slow releasing polymeric prodrugs (P-Dex-slow) and fast releasing polymeric prodrugs (P-Dex-fast), were evaluated in an adjuvant-induced arthritis rat model with an equivalent dose treatment design. It was found that after a single i.v. injection, the formulations with the slower drug release kinetics (i.e. M-Dex and P-Dex-slow) maintained longer duration of therapeutic activity than those with relatively faster drug release kinetics, resulting in better joint protection. This finding will be instructional in the future development and optimization of nanomedicines for the clinical management of rheumatoid arthritis. The outcome of this study also illustrates the value of such head-to-head comparison studies in translational nanomedicine research. PMID:24341611

Strength Analysis and Reliability Evaluation for Speed Reducers

NASA Astrophysics Data System (ADS)

Tsai, Yuo-Tern; Hsu, Yung-Yuan

2017-09-01

This paper studies the structural stresses of differential drive (DD) and harmonic drive (HD) for design improvement of reducers. The designed principles of the two reducers are reported for function comparison. The critical components of the reducers are constructed for performing motion simulation and stress analysis. DD is designed based on differential displacement of the decelerated gear ring as well as HD on a flexible spline. Finite element method (FEM) is used to analyze the structural stresses including the dynamic properties of the reducers. The stresses including kinematic properties of the two reducers are compared to observe the properties of the designs. The analyzed results are applied to identify the allowable loads of the reducers in use. The reliabilities of the reducers in different loads are further calculated according to the variation of stress. The studied results are useful on engineering analysis and reliability evaluation for designing a speed reducer with high ratios.

Comparison of CFD-calculations of centrifugal compressor stages by NUMECA Fine Turbo and ANSYS CFX programs

NASA Astrophysics Data System (ADS)

Galerkin, Y. B.; Voinov, I. B.; Drozdov, A. A.

2017-08-01

Computational Fluid Dynamics (CFD) methods are widely used for centrifugal compressors design and flow analysis. The calculation results are dependent on the chosen software, turbulence models and solver settings. Two of the most widely applicable programs are NUMECA Fine Turbo and ANSYS CFX. The objects of the study were two different stages. CFD-calculations were made for a single blade channel and for full 360-degree flow paths. Stage 1 with 3D impeller and vaneless diffuser was tested experimentally. Its flow coefficient is 0.08 and loading factor is 0.74. For stage 1 calculations were performed with different grid quality, a different number of cells and different models of turbulence. The best results have demonstrated the Spalart-Allmaras model and mesh with 1.854 million cells. Stage 2 with return channel, vaneless diffuser and 3D impeller with flow coefficient 0.15 and loading factor 0.5 was designed by the known Universal Modeling Method. Its performances were calculated by the well identified Math model. Stage 2 performances by CFD calculations shift to higher flow rate in comparison with design performances. The same result was obtained for stage 1 in comparison with measured performances. Calculated loading factor is higher in both cases for a single blade channel. Loading factor performance calculated for full flow path (“360 degrees”) by ANSYS CFX is in satisfactory agreement with the stage 2 design performance. Maximum efficiency is predicted accurately by the ANSYS CFX “360 degrees” calculation. “Sector” calculation is less accurate. Further research is needed to solve the problem of performances mismatch.

Exergy Analysis of Rocket Systems

NASA Technical Reports Server (NTRS)

Gilbert, Andrew; Mesmer, Bryan; Watson, Michael D.

2015-01-01

Exergy is defined as the useful work available from a system in a specified environment. Exergy analysis allows for comparison between different system designs, and allows for comparison of subsystem efficiencies within system designs. The proposed paper explores the relationship between the fundamental rocket equation and an exergy balance equation. A previously derived exergy equation related to rocket systems is investigated, and a higher fidelity analysis will be derived. The exergy assessments will enable informed, value-based decision making when comparing alternative rocket system designs, and will allow the most efficient configuration among candidate configurations to be determined.

The Aerodynamic Optimization of Wings at Subsonic Speeds and the Influence of Wingtip Design. Thesis

NASA Technical Reports Server (NTRS)

Zimmer, H.

1987-01-01

Some of the objectives of modern aircraft development are related to the achievement of reduced fuel consumption and aircraft noise. This investigation is mainly concerned with the aerodynamic aspects of aircraft development, i.e., reduction of induced drag. New studies of wing design, and in particular wing tips, are considered. Induced drag is important since, in cruising flight, it accounts for approximately one-third of the entire drag for the aircraft, and one-half while climbing. A survey is presented for the wing geometries and wing tip designs studied, and theoretical investigations of different planar wings with systematically varied wing tip forms are conducted. Attention is also paid to a theoretical study of some planar and nonplanar wings and their comparison with experimental data.

In-Space Transportation for GEO Space Solar Power Satellites

NASA Technical Reports Server (NTRS)

Martin, James A.; Donnahue, Benjamin B.; Henley, Mark W.

1999-01-01

This report summarizes results of study tasks to evaluate design options for in-space transportation of geostationary Space Solar Power Satellites. Referring to the end-to-end architecture studies performed in 1988, this current activity focuses on transportation of Sun Tower satellite segments from an initial low Earth orbit altitude to a final position in geostationary orbit (GEO; i.e., 35,786 km altitude, circular, equatorial orbit). This report encompasses study activity for In-Space Transportation of GEO Space Solar Power (SSP) Satellites including: 1) assessment of requirements, 2) design of system concepts, 3) comparison of alternative system options, and 4) assessment of potential derivatives.

High-Fidelity Aerostructural Design Optimization of Transport Aircraft with Continuous Morphing Trailing Edge Technology

NASA Astrophysics Data System (ADS)

Burdette, David A., Jr.

Adaptive morphing trailing edge technology offers the potential to decrease the fuel burn of transonic commercial transport aircraft by allowing wings to dynamically adjust to changing flight conditions. Current configurations allow flap and aileron droop; however, this approach provides limited degrees of freedom and increased drag produced by gaps in the wing's surface. Leading members in the aeronautics community including NASA, AFRL, Boeing, and a number of academic institutions have extensively researched morphing technology for its potential to improve aircraft efficiency. With modern computational tools it is possible to accurately and efficiently model aircraft configurations in order to quantify the efficiency improvements offered by mor- phing technology. Coupled high-fidelity aerodynamic and structural solvers provide the capability to model and thoroughly understand the nuanced trade-offs involved in aircraft design. This capability is important for a detailed study of the capabilities of morphing trailing edge technology. Gradient-based multidisciplinary design opti- mization provides the ability to efficiently traverse design spaces and optimize the trade-offs associated with the design. This thesis presents a number of optimization studies comparing optimized config- urations with and without morphing trailing edge devices. The baseline configuration used throughout this work is the NASA Common Research Model. The first opti- mization comparison considers the optimal fuel burn predicted by the Breguet range equation at a single cruise point. This initial singlepoint optimization comparison demonstrated a limited fuel burn savings of less than 1%. Given the effectiveness of the passive aeroelastic tailoring in the optimized non-morphing wing, the singlepoint optimization offered limited potential for morphing technology to provide any bene- fit. To provide a more appropriate comparison, a number of multipoint optimizations were performed. With a 3-point stencil, the morphing wing burned 2.53% less fuel than its optimized non-morphing counterpart. Expanding further to a 7-point stencil, the morphing wing used 5.04% less fuel. Additional studies demonstrate that the size of the morphing device can be reduced without sizable performance reductions, and that as aircraft wings' aspect ratios increase, the effectiveness of morphing trailing edge devices increases. The final set of studies in this thesis consider mission analy- sis, including climb, multi-altitude cruise, and descent. These mission analyses were performed with a number of surrogate models, trained with O(100) optimizations. These optimizations demonstrated fuel burn reductions as large as 5% at off-design conditions. The fuel burn predicted by the mission analysis was up to 2.7% lower for the morphing wing compared to the conventional configuration.

The Importance of Considering Differences in Study Design in Network Meta-analysis: An Application Using Anti-Tumor Necrosis Factor Drugs for Ulcerative Colitis.

PubMed

Cameron, Chris; Ewara, Emmanuel; Wilson, Florence R; Varu, Abhishek; Dyrda, Peter; Hutton, Brian; Ingham, Michael

2017-11-01

Adaptive trial designs present a methodological challenge when performing network meta-analysis (NMA), as data from such adaptive trial designs differ from conventional parallel design randomized controlled trials (RCTs). We aim to illustrate the importance of considering study design when conducting an NMA. Three NMAs comparing anti-tumor necrosis factor drugs for ulcerative colitis were compared and the analyses replicated using Bayesian NMA. The NMA comprised 3 RCTs comparing 4 treatments (adalimumab 40 mg, golimumab 50 mg, golimumab 100 mg, infliximab 5 mg/kg) and placebo. We investigated the impact of incorporating differences in the study design among the 3 RCTs and presented 3 alternative methods on how to convert outcome data derived from one form of adaptive design to more conventional parallel RCTs. Combining RCT results without considering variations in study design resulted in effect estimates that were biased against golimumab. In contrast, using the 3 alternative methods to convert outcome data from one form of adaptive design to a format more consistent with conventional parallel RCTs facilitated more transparent consideration of differences in study design. This approach is more likely to yield appropriate estimates of comparative efficacy when conducting an NMA, which includes treatments that use an alternative study design. RCTs based on adaptive study designs should not be combined with traditional parallel RCT designs in NMA. We have presented potential approaches to convert data from one form of adaptive design to more conventional parallel RCTs to facilitate transparent and less-biased comparisons.

Optimization of PET instrumentation for brain activation studies

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

Dahlbom, M.; Cherry, S.R.; Hoffman, E.J.

By performing cerebral blood flow studies with positron emission tomography (PET), and comparing blood flow images of different states of activation, functional mapping of the brain is possible. The ability of current commercial instruments to perform such studies is investigated in this work, based on a comparison of noise equivalent count (NEC) rates. Differences in the NEC performance of the different scanners in conjunction with scanner design parameters, provide insights into the importance of block design (size, dead time, crystal thickness) and overall scanner design (sensitivity and scatter fraction) for optimizing data from activation studies. The newer scanners with removablemore » septa, operating with 3-D acquisition, have much higher sensitivity, but require new methodology for optimized operation. Only by administering multiple low doses (fractionation) of the flow tracer can the high sensitivity be utilized.« less

Space station Simulation Computer System (SCS) study for NASA/MSFC. Volume 3: Refined conceptual design report

NASA Technical Reports Server (NTRS)

1989-01-01

The results of the refined conceptual design phase (task 5) of the Simulation Computer System (SCS) study are reported. The SCS is the computational portion of the Payload Training Complex (PTC) providing simulation based training on payload operations of the Space Station Freedom (SSF). In task 4 of the SCS study, the range of architectures suitable for the SCS was explored. Identified system architectures, along with their relative advantages and disadvantages for SCS, were presented in the Conceptual Design Report. Six integrated designs-combining the most promising features from the architectural formulations-were additionally identified in the report. The six integrated designs were evaluated further to distinguish the more viable designs to be refined as conceptual designs. The three designs that were selected represent distinct approaches to achieving a capable and cost effective SCS configuration for the PTC. Here, the results of task 4 (input to this task) are briefly reviewed. Then, prior to describing individual conceptual designs, the PTC facility configuration and the SSF systems architecture that must be supported by the SCS are reviewed. Next, basic features of SCS implementation that have been incorporated into all selected SCS designs are considered. The details of the individual SCS designs are then presented before making a final comparison of the three designs.

Low-cost floating emergence net and bottle trap: Comparison of two designs

USGS Publications Warehouse

Cadmus, Pete; Pomeranz, Justin; Kraus, Johanna M.

2016-01-01

Sampling emergent aquatic insects is of interest to many freshwater ecologists. Many quantitative emergence traps require the use of aspiration for collection. However, aspiration is infeasible in studies with large amounts of replication that is often required in large biomonitoring projects. We designed an economic, collapsible pyramid-shaped floating emergence trap with an external collection bottle that avoids the need for aspiration. This design was compared experimentally to a design of similar dimensions that relied on aspiration to ensure comparable results. The pyramid-shaped design captured twice as many total emerging insects. When a preservative was used in bottle collectors, >95% of the emergent abundance was collected in the bottle. When no preservative was used, >81% of the total insects were collected from the bottle. In addition to capturing fewer emergent insects, the traps that required aspiration took significantly longer to sample. Large studies and studies sampling remote locations could benefit from the economical construction, speed of sampling, and capture efficiency.

A SAS-based solution to evaluate study design efficiency of phase I pediatric oncology trials via discrete event simulation.

PubMed

Barrett, Jeffrey S; Jayaraman, Bhuvana; Patel, Dimple; Skolnik, Jeffrey M

2008-06-01

Previous exploration of oncology study design efficiency has focused on Markov processes alone (probability-based events) without consideration for time dependencies. Barriers to study completion include time delays associated with patient accrual, inevaluability (IE), time to dose limiting toxicities (DLT) and administrative and review time. Discrete event simulation (DES) can incorporate probability-based assignment of DLT and IE frequency, correlated with cohort in the case of DLT, with time-based events defined by stochastic relationships. A SAS-based solution to examine study efficiency metrics and evaluate design modifications that would improve study efficiency is presented. Virtual patients are simulated with attributes defined from prior distributions of relevant patient characteristics. Study population datasets are read into SAS macros which select patients and enroll them into a study based on the specific design criteria if the study is open to enrollment. Waiting times, arrival times and time to study events are also sampled from prior distributions; post-processing of study simulations is provided within the decision macros and compared across designs in a separate post-processing algorithm. This solution is examined via comparison of the standard 3+3 decision rule relative to the "rolling 6" design, a newly proposed enrollment strategy for the phase I pediatric oncology setting.

Study of the application of hydrogen fuel to long-range subsonic transport aircraft, volume 2

NASA Technical Reports Server (NTRS)

Brewer, G. D.; Morris, R. E.; Lange, R. H.; Moore, J. W.

1975-01-01

The feasibility, practicability, and potential advantages/disadvantages of using liquid hydrogen as fuel in long range, subsonic transport aircraft of advanced design were studied. Both passenger and cargo-type aircraft were investigated. To provide a valid basis for comparison, conventional hydrocarbon (Jet A) fueled aircraft were designed to perform identical missions using the same advanced technology and meeting the same operational constraints. The liquid hydrogen and Jet A fueled aircraft were compared on the basis of weight, size, energy utilization, cost, noise, emissions, safety, and operational characteristics. A program of technology development was formulated.

Evaluation of laminar flow control systems for subsonic commercial transport aircraft: Executive summary

NASA Technical Reports Server (NTRS)

Pearce, W. E.

1982-01-01

An evaluation was made of laminar flow control (LFC) system concepts for subsonic commercial transport aircraft. Configuration design studies, performance analyses, fabrication development, structural testing, wind tunnel testing, and contamination-avoidance techniques were included. As a result of trade studies, a configuration with LFC on the upper wing surface only, utilizing an electron beam-perforated suction surface, and employing a retractable high-lift shield for contamination avoidance, was selected as the most practical LFC system. The LFC aircraft was then compared with an advanced turbulent aircraft designed for the same mission. This comparison indicated significant fuel savings.

Advanced subsonic long-haul transport terminal area compatibility study. Volume 1: Compatibility assessment

NASA Technical Reports Server (NTRS)

1974-01-01

An analysis was made to identify airplane research and technology necessary to ensure advanced transport aircraft the capability of accommodating forecast traffic without adverse impact on airport communities. Projections were made of the delay, noise, and emissions impact of future aircraft fleets on typical large urban airport. Design requirements, based on these projections, were developed for an advanced technology, long-haul, subsonic transport. A baseline aircraft was modified to fulfill the design requirements for terminal area compatibility. Technical and economic comparisons were made between these and other aircraft configured to support the study.

A Comparison of Logistic Regression, Neural Networks, and Classification Trees Predicting Success of Actuarial Students

ERIC Educational Resources Information Center

Schumacher, Phyllis; Olinsky, Alan; Quinn, John; Smith, Richard

2010-01-01

The authors extended previous research by 2 of the authors who conducted a study designed to predict the successful completion of students enrolled in an actuarial program. They used logistic regression to determine the probability of an actuarial student graduating in the major or dropping out. They compared the results of this study with those…

Development and Evaluation of a Short Anger Management Group for Special Education Teachers in Greece: A Preliminary Study

ERIC Educational Resources Information Center

Vassilopoulos, Stephanos P.; Brouzos, Andreas; Moberly, Nicholas J.; Tsiligiannis, Georgia

2015-01-01

This study investigated the efficacy of a psychoeducational group for Greek special education teachers, all but one of whom reported experiencing anger in class. An anger management program was designed, which included a short, four-session package to be given within two weeks. The results of a pretest-posttest comparison revealed reductions in…

Cost and Search Result Comparisons of BRS After Dark and Knowledge Index.

ERIC Educational Resources Information Center

Cloud, Gayla Staples; Hambric, Jacqueline

This two-part study was designed (1) to determine differences in the costs of searching BRS After Dark (BRS AD) and Knowledge Index (KI) generally and across ten selected databases, and (2) to determine whether there is a difference in the citations retrieved when the same search is conducted on the same database in both systems. Study methodology…

A Comparison of Students' Performance under Full-Time, Part-Time, and Online Conditions in an Undergraduate Nursing Microbiology Course

ERIC Educational Resources Information Center

Carbanaro, Michael; Dawber, Tess; Arav, Isanna

2006-01-01

The purpose of this study was to compare undergraduate nursing students' achievement on examinations for three groups in a mandatory microbiology course. The study represents one aspect of a larger research project designed to gain insight into factors that may influence online learning for distance education nursing students at a Canadian…

Immigrant Parents' Choice of a Bilingual versus Monolingual Kindergarten for Second-Generation Children: Motives, Attitudes, and Factors

ERIC Educational Resources Information Center

Schwartz, Mila; Moin, Victor; Leikin, Mark; Breitkopf, Anna

2010-01-01

This study investigated how immigrant parents describe and explain their family language policy concerning their child's preschool bilingual development, and also explored the factors linked to the parents' choice of bilingual or monolingual kindergarten for their child. The study design was based on a comparison of 2 groups of parents: those who…

Supporting Learning with Weblogs in Science Education: A Comparison of Blogging and Hand-Written Reflective Writing with and without Prompts

ERIC Educational Resources Information Center

Petko, Dominik; Egger, Nives; Graber, Marc

2014-01-01

The goal of this study was to compare how weblogs and traditional handwritten reflective learning protocols compare regarding the use of cognitive and metacognitive strategies for knowledge acquisition as well as learning gains in secondary school students. The study used a quasi-experimental control group design with repeated measurements…

Does Online Learning Deliver? A Comparison of Student Teacher Outcomes from Candidates in Face-to-Face and Online Program Pathways

ERIC Educational Resources Information Center

Mollenkopf, Dawn; Vu, Phu; Crow, Sherry; Black, Chilene

2017-01-01

Although a growing number of students are accessing online learning programs, there are concerns about the quality of these programs. Multiple reports examined online program quality, but many of those studies had methodology and design issues that make it difficult to interpret the findings conclusively. This study attempted to address the…

Examining the Effects of Adapted Peer Tutoring on Social and Language Skills of Young English Language Learners

ERIC Educational Resources Information Center

Xu, Yaoying

2015-01-01

The purpose of this study was to examine the effects of adapted peer tutoring (APT) on social interactions and early language and literacy skills of pre-school-age children who were English language learners (ELLs). APT was the treatment for this study. Quasi-experimental group comparison design was applied. Two inclusive pre-school classrooms…

A Comparison of Learning Management Systems in a School District: Searching for the Ideal Personalized Integrated Educational System (PIES)

ERIC Educational Resources Information Center

Yildirim, Zahide; Reigeluth, Charles M.; Kwon, Seolim; Kageto, Yuichi; Shao, Zihang

2014-01-01

This study explored the use of several learning management systems (LMS), their benefits, and their limitations in relation to the desired characteristics of an ideal Personalized Integrated Educational System (PIES) for the information age. A qualitative research design was used. The participants of the study were teachers, administrators, and…

Spelling Practice Intervention: A Comparison of Tablet PC and Picture Cards as Spelling Practice Methods for Students with Developmental Disabilities

ERIC Educational Resources Information Center

Seok, Soonhwa; DaCosta, Boaventura; Yu, Byeong Min

2015-01-01

The present study compared a spelling practice intervention using a tablet personal computer (PC) and picture cards with three students diagnosed with developmental disabilities. An alternating-treatments design with a non-concurrent multiple-baseline across participants was used. The aims of the present study were: (a) to determine if…

Generation of NEP heliocentric trajectory data

NASA Technical Reports Server (NTRS)

Horsewood, J. L.; Brice, K. B.

1972-01-01

A study, designed to generate representative nuclear electric propulsion data for rendezvous missions to the comet Encke using the variational calculus program HILTOP, is presented. Other purposes of the study include a comparison of the HILTOP data with equivalent data generated with QUICKTOP program and to propose approaches for storing and subsequently accessing the optimum trajectory and performance data in the QUICKLY program.

Emotion Self-Regulation: A Mixed-Methods Intervention Study of Socioemotional and Reading Outcomes of High School Students with Reading Difficulties

ERIC Educational Resources Information Center

Novosel, Leslie C.

2012-01-01

Employing multiple methods, including a comparison group pre/posttest design and student interviews and self-reflections, this study represents an initial attempt to investigate the efficacy of a social and emotional learning self-regulation strategy relative to the general reading ability, reading self-concept, and social and emotional well-being…