Science.gov

Sample records for systematic design methodology

  1. Systematic Controller Design Methodology for Variable-Speed Wind Turbines

    SciTech Connect

    Hand, M. M.; Balas, M. J.

    2002-02-01

    Variable-speed, horizontal axis wind turbines use blade-pitch control to meet specified objectives for three operational regions. This paper provides a guide for controller design for the constant power production regime. A simple, rigid, non-linear turbine model was used to systematically perform trade-off studies between two performance metrics. Minimization of both the deviation of the rotor speed from the desired speed and the motion of the actuator is desired. The robust nature of the proportional-integral-derivative controller is illustrated, and optimal operating conditions are determined. Because numerous simulation runs may be completed in a short time, the relationship between the two opposing metrics is easily visualized.

  2. Systematic defect filtering and data analysis methodology for design based metrology

    NASA Astrophysics Data System (ADS)

    Yang, Hyunjo; Kim, Jungchan; Lee, Taehyeong; Jung, Areum; Yoo, Gyun; Yim, Donggyu; Park, Sungki; Hasebe, Toshiaki; Yamamoto, Masahiro; Cai, Jun

    2009-03-01

    Recently several Design Based Metrologies (DBMs) are introduced and being in use for wafer verification. The major applications of DBM are OPC accuracy improvement, DFM feed-back through Process Window Qualification (PWQ) and advanced process control. In general, however, the amount of output data from DBM is normally so large that it is very hard to handle the data for valuable feed-back. In case of PWQ, more than thousands of hot spots are detected on a single chip at the edge of process window. So, it takes much time and labor to review and analyze all the hot spots detected at PWQ. Design-related systematic defects, however, will be found repeatedly and if they can be classified into groups, it would be possible to save a lot of time for the analysis. We have demonstrated an EDA tool which can handle the large amount of output data from DBM by reducing pattern defects to groups. It can classify millions of patterns into less than thousands of pattern groups. It has been evaluated on the analysis of PWQ of metal layer in NAND Flash memory device and random contact hole patterns in a DRAM device. The result shows that this EDA tool can handle the CD measurement data easily and can save us a lot of time and labor for the analysis. The procedures of systematic defect filtering and data handling using an EDA tool are presented in detail

  3. Systematic Review Methodology in Higher Education

    ERIC Educational Resources Information Center

    Bearman, Margaret; Smith, Calvin D.; Carbone, Angela; Slade, Susan; Baik, Chi; Hughes-Warrington, Marnie; Neumann, David L.

    2012-01-01

    Systematic review methodology can be distinguished from narrative reviews of the literature through its emphasis on transparent, structured and comprehensive approaches to searching the literature and its requirement for formal synthesis of research findings. There appears to be relatively little use of the systematic review methodology within the…

  4. Variable-Speed Wind Turbine Controller Systematic Design Methodology: A Comparison of Non-Linear and Linear Model-Based Designs

    SciTech Connect

    Hand, M. M.

    1999-07-30

    Variable-speed, horizontal axis wind turbines use blade-pitch control to meet specified objectives for three regions of operation. This paper focuses on controller design for the constant power production regime. A simple, rigid, non-linear turbine model was used to systematically perform trade-off studies between two performance metrics. Minimization of both the deviation of the rotor speed from the desired speed and the motion of the actuator is desired. The robust nature of the proportional-integral-derivative (PID) controller is illustrated, and optimal operating conditions are determined. Because numerous simulation runs may be completed in a short time, the relationship of the two opposing metrics is easily visualized. Traditional controller design generally consists of linearizing a model about an operating point. This step was taken for two different operating points, and the systematic design approach was used. A comparison of the optimal regions selected using the n on-linear model and the two linear models shows similarities. The linearization point selection does, however, affect the turbine performance slightly. Exploitation of the simplicity of the model allows surfaces consisting of operation under a wide range of gain values to be created. This methodology provides a means of visually observing turbine performance based upon the two metrics chosen for this study. Design of a PID controller is simplified, and it is possible to ascertain the best possible combination of controller parameters. The wide, flat surfaces indicate that a PID controller is very robust in this variable-speed wind turbine application.

  5. Vending machine assessment methodology. A systematic review.

    PubMed

    Matthews, Melissa A; Horacek, Tanya M

    2015-07-01

    The nutritional quality of food and beverage products sold in vending machines has been implicated as a contributing factor to the development of an obesogenic food environment. How comprehensive, reliable, and valid are the current assessment tools for vending machines to support or refute these claims? A systematic review was conducted to summarize, compare, and evaluate the current methodologies and available tools for vending machine assessment. A total of 24 relevant research studies published between 1981 and 2013 met inclusion criteria for this review. The methodological variables reviewed in this study include assessment tool type, study location, machine accessibility, product availability, healthfulness criteria, portion size, price, product promotion, and quality of scientific practice. There were wide variations in the depth of the assessment methodologies and product healthfulness criteria utilized among the reviewed studies. Of the reviewed studies, 39% evaluated machine accessibility, 91% evaluated product availability, 96% established healthfulness criteria, 70% evaluated portion size, 48% evaluated price, 52% evaluated product promotion, and 22% evaluated the quality of scientific practice. Of all reviewed articles, 87% reached conclusions that provided insight into the healthfulness of vended products and/or vending environment. Product healthfulness criteria and complexity for snack and beverage products was also found to be variable between the reviewed studies. These findings make it difficult to compare results between studies. A universal, valid, and reliable vending machine assessment tool that is comprehensive yet user-friendly is recommended. PMID:25772195

  6. Methodology of systematic reviews and recommendations.

    PubMed

    Furlan, Julio C; Singh, Jeffrey; Hsieh, Jane; Fehlings, Michael G

    2011-08-01

    Although research in the field of spinal cord injury (SCI) is a relatively new endeavor, a remarkable number of papers focused on this subspecialty have been published in a broad variety of journals over the last two decades. A multidisciplinary group of experts, including clinical epidemiologists, neurosurgical and orthopedic spine surgeons, basic scientists, rehabilitation specialists, intensivists, and allied health professionals (nursing and physical therapy) was assembled through the Spinal Cord Injury Solutions Network to summarize the existing literature focusing on 12 key topics related to acute traumatic SCI, which have not been recently reviewed. The objective was to develop evidence-based recommendations to help translate current science into clinical practice and to identify new directions for research. For each topic one to three specific questions were formulated by consensus through the expert panel. A systematic review of the literature was performed to determine the current evidence for the specific questions. A primary literature search was performed using MEDLINE, CINAHL, EMBASE, and Cochrane databases. A secondary search strategy incorporated additional articles referenced in significant publications (i.e., meta-analysis, systematic and nonsystematic review articles). Two reviewers independently reviewed the titles and abstracts yielded by this comprehensive search and subsequently selected articles based on the predetermined inclusion and inclusion criteria. Data were extracted for population into evidentiary tables. Selected articles were rated for level of evidence and methodological quality, information that was also included in evidentiary tables. Disagreements were resolved by a third reviewer or consensus-based discussion. Based on the evidence compiled, answers to the targeted questions were formulated and recommendations generated by consensus-based discussion and anonymized voting using Delphi methodology. A level of consensus of 80

  7. Permanent magnet design methodology

    NASA Technical Reports Server (NTRS)

    Leupold, Herbert A.

    1991-01-01

    Design techniques developed for the exploitation of high energy magnetically rigid materials such as Sm-Co and Nd-Fe-B have resulted in a revolution in kind rather than in degree in the design of a variety of electron guidance structures for ballistic and aerospace applications. Salient examples are listed. Several prototype models were developed. These structures are discussed in some detail: permanent magnet solenoids, transverse field sources, periodic structures, and very high field structures.

  8. Solid lubrication design methodology

    NASA Technical Reports Server (NTRS)

    Aggarwal, B. B.; Yonushonis, T. M.; Bovenkerk, R. L.

    1984-01-01

    A single element traction rig was used to measure the traction forces at the contact of a ball against a flat disc at room temperature under combined rolling and sliding. The load and speed conditions were selected to match those anticipated for bearing applications in adiabatic diesel engines. The test program showed that the magnitude of traction forces were almost the same for all the lubricants tested; a lubricant should, therefore, be selected on the basis of its ability to prevent wear of the contact surfaces. Traction vs. slide/roll ratio curves were similar to those for liquid lubricants but the traction forces were an order of magnitude higher. The test data was used to derive equations to predict traction force as a function of contact stress and rolling speed. Qualitative design guidelines for solid lubricated concentrated contacts are proposed.

  9. Fixed or random effects meta-analysis? Common methodological issues in systematic reviews of effectiveness.

    PubMed

    Tufanaru, Catalin; Munn, Zachary; Stephenson, Matthew; Aromataris, Edoardo

    2015-09-01

    Systematic review aims to systematically identify, critically appraise, and summarize all relevant studies that match predefined criteria and answer predefined questions. The most common type of systematic review is that assessing the effectiveness of an intervention or therapy. In this article, we discuss some of the common methodological issues that arise when conducting systematic reviews and meta-analyses of effectiveness data, including issues related to study designs, meta-analysis, and the use and interpretation of effect sizes. PMID:26355603

  10. Methodological quality of behavioural weight loss studies: a systematic review.

    PubMed

    Lemon, S C; Wang, M L; Haughton, C F; Estabrook, D P; Frisard, C F; Pagoto, S L

    2016-07-01

    This systematic review assessed the methodological quality of behavioural weight loss intervention studies conducted among adults and associations between quality and statistically significant weight loss outcome, strength of intervention effectiveness and sample size. Searches for trials published between January, 2009 and December, 2014 were conducted using PUBMED, MEDLINE and PSYCINFO and identified ninety studies. Methodological quality indicators included study design, anthropometric measurement approach, sample size calculations, intent-to-treat (ITT) analysis, loss to follow-up rate, missing data strategy, sampling strategy, report of treatment receipt and report of intervention fidelity (mean = 6.3). Indicators most commonly utilized included randomized design (100%), objectively measured anthropometrics (96.7%), ITT analysis (86.7%) and reporting treatment adherence (76.7%). Most studies (62.2%) had a follow-up rate > 75% and reported a loss to follow-up analytic strategy or minimal missing data (69.9%). Describing intervention fidelity (34.4%) and sampling from a known population (41.1%) were least common. Methodological quality was not associated with reporting a statistically significant result, effect size or sample size. This review found the published literature of behavioural weight loss trials to be of high quality for specific indicators, including study design and measurement. Identified for improvement include utilization of more rigorous statistical approaches to loss to follow up and better fidelity reporting. PMID:27071775

  11. Systematic Comparison of Operating Reserve Methodologies: Preprint

    SciTech Connect

    Ibanez, E.; Krad, I.; Ela, E.

    2014-04-01

    Operating reserve requirements are a key component of modern power systems, and they contribute to maintaining reliable operations with minimum economic impact. No universal method exists for determining reserve requirements, thus there is a need for a thorough study and performance comparison of the different existing methodologies. Increasing penetrations of variable generation (VG) on electric power systems are posed to increase system uncertainty and variability, thus the need for additional reserve also increases. This paper presents background information on operating reserve and its relationship to VG. A consistent comparison of three methodologies to calculate regulating and flexibility reserve in systems with VG is performed.

  12. A Systematic Methodology for Verifying Superscalar Microprocessors

    NASA Technical Reports Server (NTRS)

    Srivas, Mandayam; Hosabettu, Ravi; Gopalakrishnan, Ganesh

    1999-01-01

    We present a systematic approach to decompose and incrementally build the proof of correctness of pipelined microprocessors. The central idea is to construct the abstraction function by using completion functions, one per unfinished instruction, each of which specifies the effect (on the observables) of completing the instruction. In addition to avoiding the term size and case explosion problem that limits the pure flushing approach, our method helps localize errors, and also handles stages with interactive loops. The technique is illustrated on pipelined and superscalar pipelined implementations of a subset of the DLX architecture. It has also been applied to a processor with out-of-order execution.

  13. Waste Package Design Methodology Report

    SciTech Connect

    D.A. Brownson

    2001-09-28

    The objective of this report is to describe the analytical methods and processes used by the Waste Package Design Section to establish the integrity of the various waste package designs, the emplacement pallet, and the drip shield. The scope of this report shall be the methodology used in criticality, risk-informed, shielding, source term, structural, and thermal analyses. The basic features and appropriateness of the methods are illustrated, and the processes are defined whereby input values and assumptions flow through the application of those methods to obtain designs that ensure defense-in-depth as well as satisfy requirements on system performance. Such requirements include those imposed by federal regulation, from both the U.S. Department of Energy (DOE) and U.S. Nuclear Regulatory Commission (NRC), and those imposed by the Yucca Mountain Project to meet repository performance goals. The report is to be used, in part, to describe the waste package design methods and techniques to be used for producing input to the License Application Report.

  14. Methodology for Designing Fault-Protection Software

    NASA Technical Reports Server (NTRS)

    Barltrop, Kevin; Levison, Jeffrey; Kan, Edwin

    2006-01-01

    A document describes a methodology for designing fault-protection (FP) software for autonomous spacecraft. The methodology embodies and extends established engineering practices in the technical discipline of Fault Detection, Diagnosis, Mitigation, and Recovery; and has been successfully implemented in the Deep Impact Spacecraft, a NASA Discovery mission. Based on established concepts of Fault Monitors and Responses, this FP methodology extends the notion of Opinion, Symptom, Alarm (aka Fault), and Response with numerous new notions, sub-notions, software constructs, and logic and timing gates. For example, Monitor generates a RawOpinion, which graduates into Opinion, categorized into no-opinion, acceptable, or unacceptable opinion. RaiseSymptom, ForceSymptom, and ClearSymptom govern the establishment and then mapping to an Alarm (aka Fault). Local Response is distinguished from FP System Response. A 1-to-n and n-to- 1 mapping is established among Monitors, Symptoms, and Responses. Responses are categorized by device versus by function. Responses operate in tiers, where the early tiers attempt to resolve the Fault in a localized step-by-step fashion, relegating more system-level response to later tier(s). Recovery actions are gated by epoch recovery timing, enabling strategy, urgency, MaxRetry gate, hardware availability, hazardous versus ordinary fault, and many other priority gates. This methodology is systematic, logical, and uses multiple linked tables, parameter files, and recovery command sequences. The credibility of the FP design is proven via a fault-tree analysis "top-down" approach, and a functional fault-mode-effects-and-analysis via "bottoms-up" approach. Via this process, the mitigation and recovery strategy(s) per Fault Containment Region scope (width versus depth) the FP architecture.

  15. Integrated Design Methodology for Highly Reliable Liquid Rocket Engine

    NASA Astrophysics Data System (ADS)

    Kuratani, Naoshi; Aoki, Hiroshi; Yasui, Masaaki; Kure, Hirotaka; Masuya, Goro

    The Integrated Design Methodology is strongly required at the conceptual design phase to achieve the highly reliable space transportation systems, especially the propulsion systems, not only in Japan but also all over the world in these days. Because in the past some catastrophic failures caused some losses of mission and vehicle (LOM/LOV) at the operational phase, moreover did affect severely the schedule delays and cost overrun at the later development phase. Design methodology for highly reliable liquid rocket engine is being preliminarily established and investigated in this study. The sensitivity analysis is systematically performed to demonstrate the effectiveness of this methodology, and to clarify and especially to focus on the correlation between the combustion chamber, turbopump and main valve as main components. This study describes the essential issues to understand the stated correlations, the need to apply this methodology to the remaining critical failure modes in the whole engine system, and the perspective on the engine development in the future.

  16. Space Engineering Projects in Design Methodology

    NASA Technical Reports Server (NTRS)

    Crawford, R.; Wood, K.; Nichols, S.; Hearn, C.; Corrier, S.; DeKunder, G.; George, S.; Hysinger, C.; Johnson, C.; Kubasta, K.

    1993-01-01

    NASA/USRA is an ongoing sponsor of space design projects in the senior design courses of the Mechanical Engineering Department at The University of Texas at Austin. This paper describes the UT senior design sequence, focusing on the first-semester design methodology course. The philosophical basis and pedagogical structure of this course is summarized. A history of the Department's activities in the Advanced Design Program is then presented. The paper includes a summary of the projects completed during the 1992-93 Academic Year in the methodology course, and concludes with an example of two projects completed by student design teams.

  17. Assuring data transparency through design methodologies

    NASA Technical Reports Server (NTRS)

    Williams, Allen

    1990-01-01

    This paper addresses the role of design methodologies and practices in the assurance of technology transparency. The development of several subsystems on large, long life cycle government programs was analyzed to glean those characteristics in the design, development, test, and evaluation that precluded or enabled the insertion of new technology. The programs examined were Minuteman, DSP, B1-B, and space shuttle. All these were long life cycle, technology-intensive programs. The design methodologies (or lack thereof) and design practices for each were analyzed in terms of the success or failure in incorporating evolving technology. Common elements contributing to the success or failure were extracted and compared to current methodologies being proposed by the Department of Defense and NASA. The relevance of these practices to the design and deployment of Space Station Freedom were evaluated. In particular, appropriate methodologies now being used on the core development contract were examined.

  18. A design methodology for unattended monitoring systems

    SciTech Connect

    SMITH,JAMES D.; DELAND,SHARON M.

    2000-03-01

    The authors presented a high-level methodology for the design of unattended monitoring systems, focusing on a system to detect diversion of nuclear materials from a storage facility. The methodology is composed of seven, interrelated analyses: Facility Analysis, Vulnerability Analysis, Threat Assessment, Scenario Assessment, Design Analysis, Conceptual Design, and Performance Assessment. The design of the monitoring system is iteratively improved until it meets a set of pre-established performance criteria. The methodology presented here is based on other, well-established system analysis methodologies and hence they believe it can be adapted to other verification or compliance applications. In order to make this approach more generic, however, there needs to be more work on techniques for establishing evaluation criteria and associated performance metrics. They found that defining general-purpose evaluation criteria for verifying compliance with international agreements was a significant undertaking in itself. They finally focused on diversion of nuclear material in order to simplify the problem so that they could work out an overall approach for the design methodology. However, general guidelines for the development of evaluation criteria are critical for a general-purpose methodology. A poor choice in evaluation criteria could result in a monitoring system design that solves the wrong problem.

  19. General Methodology for Designing Spacecraft Trajectories

    NASA Technical Reports Server (NTRS)

    Condon, Gerald; Ocampo, Cesar; Mathur, Ravishankar; Morcos, Fady; Senent, Juan; Williams, Jacob; Davis, Elizabeth C.

    2012-01-01

    A methodology for designing spacecraft trajectories in any gravitational environment within the solar system has been developed. The methodology facilitates modeling and optimization for problems ranging from that of a single spacecraft orbiting a single celestial body to that of a mission involving multiple spacecraft and multiple propulsion systems operating in gravitational fields of multiple celestial bodies. The methodology consolidates almost all spacecraft trajectory design and optimization problems into a single conceptual framework requiring solution of either a system of nonlinear equations or a parameter-optimization problem with equality and/or inequality constraints.

  20. Applying Software Design Methodology to Instructional Design

    ERIC Educational Resources Information Center

    East, J. Philip

    2004-01-01

    The premise of this paper is that computer science has much to offer the endeavor of instructional improvement. Software design processes employed in computer science for developing software can be used for planning instruction and should improve instruction in much the same manner that design processes appear to have improved software. Techniques…

  1. Applying Software Design Methodology to Instructional Design

    NASA Astrophysics Data System (ADS)

    East, J. Philip

    2004-12-01

    The premise of this paper is that computer science has much to offer the endeavor of instructional improvement. Software design processes employed in computer science for developing software can be used for planning instruction and should improve instruction in much the same manner that design processes appear to have improved software. Techniques for examining the software development process can be applied to an examination of the instructional process. Furthermore, the computer science discipline is particularly well suited to these tasks. Thus, computer science can develop instructional design expertise for export to other disciplines to improve education in all disciplines and, eventually, at all levels.

  2. Design methodologies for silicon photonic integrated circuits

    NASA Astrophysics Data System (ADS)

    Chrostowski, Lukas; Flueckiger, Jonas; Lin, Charlie; Hochberg, Michael; Pond, James; Klein, Jackson; Ferguson, John; Cone, Chris

    2014-03-01

    This paper describes design methodologies developed for silicon photonics integrated circuits. The approach presented is inspired by methods employed in the Electronics Design Automation (EDA) community. This is complemented by well established photonic component design tools, compact model synthesis, and optical circuit modelling. A generic silicon photonics design kit, as described here, is available for download at http://www.siepic.ubc.ca/GSiP.

  3. Methodological Alignment in Design-Based Research

    ERIC Educational Resources Information Center

    Hoadley, Christopher M.

    2004-01-01

    Empirical research is all about trying to model and predict the world. In this article, I discuss how design-based research methods can help do this effectively. In particular, design-based research methods can help with the problem of methodological alignment: ensuring that the research methods we use actually test what we think they are testing.…

  4. Design methodology and projects for space engineering

    NASA Technical Reports Server (NTRS)

    Nichols, S.; Kleespies, H.; Wood, K.; Crawford, R.

    1993-01-01

    NASA/USRA is an ongoing sponsor of space design projects in the senior design course of the Mechanical Engineering Department at The University of Texas at Austin. This paper describes the UT senior design sequence, consisting of a design methodology course and a capstone design course. The philosophical basis of this sequence is briefly summarized. A history of the Department's activities in the Advanced Design Program is then presented. The paper concludes with a description of the projects completed during the 1991-92 academic year and the ongoing projects for the Fall 1992 semester.

  5. Integrating rock mechanics issues with repository design through design process principles and methodology

    SciTech Connect

    Bieniawski, Z.T.

    1996-04-01

    A good designer needs not only knowledge for designing (technical know-how that is used to generate alternative design solutions) but also must have knowledge about designing (appropriate principles and systematic methodology to follow). Concepts such as {open_quotes}design for manufacture{close_quotes} or {open_quotes}concurrent engineering{close_quotes} are widely used in the industry. In the field of rock engineering, only limited attention has been paid to the design process because design of structures in rock masses presents unique challenges to the designers as a result of the uncertainties inherent in characterization of geologic media. However, a stage has now been reached where we are be able to sufficiently characterize rock masses for engineering purposes and identify the rock mechanics issues involved but are still lacking engineering design principles and methodology to maximize our design performance. This paper discusses the principles and methodology of the engineering design process directed to integrating site characterization activities with design, construction and performance of an underground repository. Using the latest information from the Yucca Mountain Project on geology, rock mechanics and starter tunnel design, the current lack of integration is pointed out and it is shown how rock mechanics issues can be effectively interwoven with repository design through a systematic design process methodology leading to improved repository performance. In essence, the design process is seen as the use of design principles within an integrating design methodology, leading to innovative problem solving. In particular, a new concept of {open_quotes}Design for Constructibility and Performance{close_quotes} is introduced. This is discussed with respect to ten rock mechanics issues identified for repository design and performance.

  6. Single-Case Experimental Designs: A Systematic Review of Published Research and Current Standards

    ERIC Educational Resources Information Center

    Smith, Justin D.

    2012-01-01

    This article systematically reviews the research design and methodological characteristics of single-case experimental design (SCED) research published in peer-reviewed journals between 2000 and 2010. SCEDs provide researchers with a flexible and viable alternative to group designs with large sample sizes. However, methodological challenges have…

  7. Failure detection system design methodology. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Chow, E. Y.

    1980-01-01

    The design of a failure detection and identification system consists of designing a robust residual generation process and a high performance decision making process. The design of these two processes are examined separately. Residual generation is based on analytical redundancy. Redundancy relations that are insensitive to modelling errors and noise effects are important for designing robust residual generation processes. The characterization of the concept of analytical redundancy in terms of a generalized parity space provides a framework in which a systematic approach to the determination of robust redundancy relations are developed. The Bayesian approach is adopted for the design of high performance decision processes. The FDI decision problem is formulated as a Bayes sequential decision problem. Since the optimal decision rule is incomputable, a methodology for designing suboptimal rules is proposed. A numerical algorithm is developed to facilitate the design and performance evaluation of suboptimal rules.

  8. Parametric design methodology for chemical processes using a simulator

    SciTech Connect

    Diwekar, U.M.; Rubin, E.S. )

    1994-02-01

    Parameter design is a method popularized by the Japanese quality expert G. Taguchi, for designing products and manufacturing processes that are robust in the face of uncontrollable variations. At the design stage, the goal of parameter design is to identify design settings that make the product performance less sensitive to the effects of manufacturing and environmental variations and deterioration. Because parameter design reduces performance variation by reducing the influence of the sources of variation rather than by controlling them, it is a cost-effective technique for improving quality. A recent study on the application of parameter design methodology for chemical processes reported that the use of Taguchi's method was not justified and a method based on Monte Carlo simulation combined with optimization was shown to be more effective. However, this method is computationally intensive as a large number of samples are necessary to achieve the given accuracy. Additionally, determination of the number of sample runs required is based on experimentation due to a lack of systematic sampling methods. In an attempt to overcome these problems, the use of a stochastic modeling capability combined with an optimizer is presented in this paper. The objective is that of providing an effective means for application of parameter design methodologies to chemical processes using the ASPEN simulator. This implementation not only presents a generalized tool for use by chemical engineers at large but also provides systematic estimates of the number of sample runs required to attain the specified accuracy. The stochastic model employs the technique of Latin hypercube sampling instead of the traditional Monte Carlo technique and hence has a great potential to reduce the required number of samples. The methodology is illustrated via an example problem of designing a chemical process.

  9. Case-Crossover Analysis of Air Pollution Health Effects: A Systematic Review of Methodology and Application

    PubMed Central

    Carracedo-Martínez, Eduardo; Taracido, Margarita; Tobias, Aurelio; Saez, Marc; Figueiras, Adolfo

    2010-01-01

    Background Case-crossover is one of the most used designs for analyzing the health-related effects of air pollution. Nevertheless, no one has reviewed its application and methodology in this context. Objective We conducted a systematic review of case-crossover (CCO) designs used to study the relationship between air pollution and morbidity and mortality, from the standpoint of methodology and application. Data sources and extraction A search was made of the MEDLINE and EMBASE databases. Reports were classified as methodologic or applied. From the latter, the following information was extracted: author, study location, year, type of population (general or patients), dependent variable(s), independent variable(s), type of CCO design, and whether effect modification was analyzed for variables at the individual level. Data synthesis The review covered 105 reports that fulfilled the inclusion criteria. Of these, 24 addressed methodological aspects, and the remainder involved the design’s application. In the methodological reports, the designs that yielded the best results in simulation were symmetric bidirectional CCO and time-stratified CCO. Furthermore, we observed an increase across time in the use of certain CCO designs, mainly symmetric bidirectional and time-stratified CCO. The dependent variables most frequently analyzed were those relating to hospital morbidity; the pollutants most often studied were those linked to particulate matter. Among the CCO-application reports, 13.6% studied effect modification for variables at the individual level. Conclusions The use of CCO designs has undergone considerable growth; the most widely used designs were those that yielded better results in simulation studies: symmetric bidirectional and time-stratified CCO. However, the advantages of CCO as a method of analysis of variables at the individual level are put to little use. PMID:20356818

  10. Waste Package Component Design Methodology Report

    SciTech Connect

    D.C. Mecham

    2004-07-12

    This Executive Summary provides an overview of the methodology being used by the Yucca Mountain Project (YMP) to design waste packages and ancillary components. This summary information is intended for readers with general interest, but also provides technical readers a general framework surrounding a variety of technical details provided in the main body of the report. The purpose of this report is to document and ensure appropriate design methods are used in the design of waste packages and ancillary components (the drip shields and emplacement pallets). The methodology includes identification of necessary design inputs, justification of design assumptions, and use of appropriate analysis methods, and computational tools. This design work is subject to ''Quality Assurance Requirements and Description''. The document is primarily intended for internal use and technical guidance for a variety of design activities. It is recognized that a wide audience including project management, the U.S. Department of Energy (DOE), the U.S. Nuclear Regulatory Commission, and others are interested to various levels of detail in the design methods and therefore covers a wide range of topics at varying levels of detail. Due to the preliminary nature of the design, readers can expect to encounter varied levels of detail in the body of the report. It is expected that technical information used as input to design documents will be verified and taken from the latest versions of reference sources given herein. This revision of the methodology report has evolved with changes in the waste package, drip shield, and emplacement pallet designs over many years and may be further revised as the design is finalized. Different components and analyses are at different stages of development. Some parts of the report are detailed, while other less detailed parts are likely to undergo further refinement. The design methodology is intended to provide designs that satisfy the safety and operational

  11. Performance-based asphalt mixture design methodology

    NASA Astrophysics Data System (ADS)

    Ali, Al-Hosain Mansour

    Today, several State D.O.T.s are being investigating the use of tire rubber with local conventional materials. Several of the ongoing investigations identified potential benefits from the use of these materials, including improvements in material properties and performance. One of the major problems is being associated with the transferability of asphalt rubber technology without appropriately considering the effects of the variety of conventional materials on mixture behavior and performance. Typically, the design of these mixtures is being adapted to the physical properties of the conventional materials by using the empirical Marshall mixture design and without considering fundamental mixture behavior and performance. Use of design criteria related to the most common modes of failure for asphalt mixtures, such as rutting, fatigue cracking, and low temperature thermal cracking have to be developed and used for identifying the "best mixture," in term of performance, for the specific local materials and loading conditions. The main objective of this study was the development of a mixture design methodology that considers mixture behavior and performance. In order to achieve this objective a laboratory investigation able to evaluate mixture properties that can be related to mixture performance, (in terms of rutting, low temperature cracking, moisture damage and fatigue), and simulating the actual field loading conditions that the material is being exposed to, was conducted. The results proved that the inclusion of rubber into asphalt mixtures improved physical characteristics such as elasticity, flexibility, rebound, aging properties, increased fatigue resistance, and reduced rutting potential. The possibility of coupling the traditional Marshall mix design method with parameters related to mixture behavior and performance was investigated. Also, the SHRP SUPERPAVE mix design methodology was reviewed and considered in this study for the development of an integrated

  12. Statins, cognition, and dementia—systematic review and methodological commentary.

    PubMed

    Power, Melinda C; Weuve, Jennifer; Sharrett, A Richey; Blacker, Deborah; Gottesman, Rebecca F

    2015-04-01

    Firm conclusions about whether mid-life or long-term statin use has an impact on cognitive decline and dementia remain elusive. Here, our objective was to systematically review, synthesize and critique the epidemiological literature that examines the relationship between statin use and cognition, so as to assess the current state of knowledge, identify gaps in our understanding, and make recommendations for future research. We summarize the findings of randomized controlled trials (RCTs) and observational studies, grouped according to study design. We discuss the methods for each, and consider likely sources of bias, such as reverse causation and confounding. Although observational studies that considered statin use at or near the time of dementia diagnosis suggest a protective effect of statins, these findings could be attributable to reverse causation. RCTs and well-conducted observational studies of baseline statin use and subsequent cognition over several years of follow-up do not support a causal preventative effect of late-life statin use on cognitive decline or dementia. Given that much of the human research on statins and cognition in the future will be observational, careful study design and analysis will be essential. PMID:25799928

  13. Statins, cognition, and dementia—systematic review and methodological commentary

    PubMed Central

    Power, Melinda C.; Weuve, Jennifer; Sharrett, A. Richey; Blacker, Deborah

    2015-01-01

    Firm conclusions about whether mid-life or long-term statin use has an impact on cognitive decline and dementia remain elusive. Here, our objective was to systematically review, synthesize and critique the epidemiological literature that examines the relationship between statin use and cognition, so as to assess the current state of knowledge, identify gaps in our understanding, and make recommendations for future research. We summarize the findings of randomized controlled trials (RCTs) and observational studies, grouped according to study design. We discuss the methods for each, and consider likely sources of bias, such as reverse causation and confounding. Although observational studies that considered statin use at or near the time of dementia diagnosis suggest a protective effect of statins, these findings could be attributable to reverse causation. RCTs and well-conducted observational studies of baseline statin use and subsequent cognition over several years of follow-up do not support a causal preventative effect of late-life statin use on cognitive decline or dementia. Given that much of the human research on statins and cognition in the future will be observational, careful study design and analysis will be essential. PMID:25799928

  14. Control/structure interaction design methodology

    NASA Technical Reports Server (NTRS)

    Briggs, Hugh C.; Layman, William E.

    1989-01-01

    The Control Structure Interaction Program is a technology development program for spacecraft that exhibit interactions between the control system and structural dynamics. The program objectives include development and verification of new design concepts (such as active structure) and new tools (such as a combined structure and control optimization algorithm) and their verification in ground and possibly flight test. The new CSI design methodology is centered around interdisciplinary engineers using new tools that closely integrate structures and controls. Verification is an important CSI theme and analysts will be closely integrated to the CSI Test Bed laboratory. Components, concepts, tools and algorithms will be developed and tested in the lab and in future Shuttle-based flight experiments. The design methodology is summarized in block diagrams depicting the evolution of a spacecraft design and descriptions of analytical capabilities used in the process. The multiyear JPL CSI implementation plan is described along with the essentials of several new tools. A distributed network of computation servers and workstations was designed that will provide a state-of-the-art development base for the CSI technologies.

  15. Design Methodology of Micro Vibration Energy Harvesters

    NASA Astrophysics Data System (ADS)

    Tanaka, Shuji

    Recently, micro vibration energy harvesters are attracting much attention for wireless sensor applications. To answer the power requirement of practical applications, the design methodology is important. This paper first reviews the fundamental theory of vibration energy harvesting, and then discusses how to design a micro vibration energy harvester at a concept level. For the micro vibration energy harvesters, independent design parameters at the top level are only the mass and stroke of a seismic mass and quality factor, while the frequency and acceleration of vibration input are given parameters determined by the application. The key design point is simply to make the mass and stroke of the seismic mass as large as possible within the available device size. Some case studies based on the theory are also presented. This paper provides a guideline for the development of the micro vibration energy harvesters.

  16. Application of systematic review methodology to the field of nutrition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Systematic reviews represent a rigorous and transparent approach of synthesizing scientific evidence that minimizes bias. They evolved within the medical community to support development of clinical and public health practice guidelines, set research agendas and formulate scientific consensus state...

  17. Systematic Review of the Methodological Quality of Studies Aimed at Creating Gestational Weight Gain Charts.

    PubMed

    Ohadike, Corah O; Cheikh-Ismail, Leila; Ohuma, Eric O; Giuliani, Francesca; Bishop, Deborah; Kac, Gilberto; Puglia, Fabien; Maia-Schlüssel, Michael; Kennedy, Stephen H; Villar, José; Hirst, Jane E

    2016-03-01

    A range of adverse outcomes is associated with insufficient and excessive maternal weight gain in pregnancy, but there is no consensus regarding what constitutes optimal gestational weight gain (GWG). Differences in the methodological quality of GWG studies may explain the varying chart recommendations. The goal of this systematic review was to evaluate the methodological quality of studies that aimed to create GWG charts by scoring them against a set of predefined, independently agreed-upon criteria. These criteria were divided into 3 domains: study design (12 criteria), statistical methods (7 criteria), and reporting methods (4 criteria). The criteria were broken down further into items, and studies were assigned a quality score (QS) based on these criteria. For each item, studies were scored as either high (score = 0) or low (score = 1) risk of bias; a high QS correlated with a low risk of bias. The maximum possible QS was 34. The systematic search identified 12 eligible studies involving 2,268,556 women from 9 countries; their QSs ranged from 9 (26%) to 29 (85%) (median, 18; 53%). The most common sources for bias were found in study designs (i.e., not prospective); assessments of prepregnancy weight and gestational age; descriptions of weighing protocols; sample size calculations; and the multiple measurements taken at each visit. There is wide variation in the methodological quality of GWG studies constructing charts. High-quality studies are needed to guide future clinical recommendations. We recommend the following main requirements for future studies: prospective design, reliable evaluation of prepregnancy weight and gestational age, detailed description of measurement procedures and protocols, description of sample-size calculation, and the creation of smooth centile charts or z scores. PMID:26980814

  18. Systematic Reviews of Animal Models: Methodology versus Epistemology

    PubMed Central

    Greek, Ray; Menache, Andre

    2013-01-01

    Systematic reviews are currently favored methods of evaluating research in order to reach conclusions regarding medical practice. The need for such reviews is necessitated by the fact that no research is perfect and experts are prone to bias. By combining many studies that fulfill specific criteria, one hopes that the strengths can be multiplied and thus reliable conclusions attained. Potential flaws in this process include the assumptions that underlie the research under examination. If the assumptions, or axioms, upon which the research studies are based, are untenable either scientifically or logically, then the results must be highly suspect regardless of the otherwise high quality of the studies or the systematic reviews. We outline recent criticisms of animal-based research, namely that animal models are failing to predict human responses. It is this failure that is purportedly being corrected via systematic reviews. We then examine the assumption that animal models can predict human outcomes to perturbations such as disease or drugs, even under the best of circumstances. We examine the use of animal models in light of empirical evidence comparing human outcomes to those from animal models, complexity theory, and evolutionary biology. We conclude that even if legitimate criticisms of animal models were addressed, through standardization of protocols and systematic reviews, the animal model would still fail as a predictive modality for human response to drugs and disease. Therefore, systematic reviews and meta-analyses of animal-based research are poor tools for attempting to reach conclusions regarding human interventions. PMID:23372426

  19. Development of a systematic methodology for evaluation of soil vapor extraction at Rocky Mountain Arsenal

    SciTech Connect

    Aamodt, E.C.; Gilmore, J.E.; Weaver, J.D.; Dahm, M.A.; Riese, A.C.; Tortoso, A.

    1994-12-31

    A systematic methodology was developed to evaluate the feasibility of using soil vapor extraction (SVE) to treat South Plants and former Basin F soil media in support of the ongoing Onpost Operable Unit Feasibility Study (FS) at Rocky Mountain Arsenal. The methodology used in situ air permeability testing, chemical and physical property characterization, and computer modeling to evaluate the potential for using SVE to treat soil contaminated with volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), and pesticide manufacturing process wastes, including potential odor-causing compounds. In situ air permeability tests were performed to measure air permeabilities and extracted vapor flow rates. Soil samples were collected at each test location and were analyzed for VOCs, low molecular weight SVOCs, potential odor-causing compounds, and physical property characteristics. In situ air permeability test and chemical and physical property characterization results were used during computer modeling evaluations to develop SVE conceptual designs, estimate remediation timeframes, select appropriate treatment technologies, and develop preliminary cost estimates for full-scale implementation. The methodology developed provides information necessary to evaluate SVE at the FS stage and provides a sound technical basis for design of full-scale SVE systems.

  20. Methodology on zoom system design and optimization

    NASA Astrophysics Data System (ADS)

    Ding, Quanxin; Liu, Hua

    2008-03-01

    For aim to establish effective methodology in research to design and evaluate on typical zoom sensor system, to satisfy the system requirements and achieve an advanced characteristics. Some methods about system analysis, especially task principle and key technique of core system, are analyzed deeply. Base on Gaussian photonics theory, zoom system differential equation, solves vector space distribution and integrated balance algorithm on global optimization system is studied. Dominate configuration of new idea system design and optimization, with which consecutive zoom and diffractive module equipped by great format photonics device, is established. The results of evaluated on a kind of typical zoom sensor system is presented, and achieves remarkable advantages on some criterions, such as Modulation Transfer Function (MTF), Spot Diagram (RMS) and Point Spread Function (PSF) etc., and in volume, weight, system efficiency and otherwise.

  1. Lean management in health care: definition, concepts, methodology and effects reported (systematic review protocol)

    PubMed Central

    2014-01-01

    Background Lean is a set of operating philosophies and methods that help create a maximum value for patients by reducing waste and waits. It emphasizes the consideration of the customer’s needs, employee involvement and continuous improvement. Research on the application and implementation of lean principles in health care has been limited. Methods This is a protocol for a systematic review, following the Cochrane Effective Practice and Organisation of Care (EPOC) methodology. The review aims to document, catalogue and synthesize the existing literature on the effects of lean implementation in health care settings especially the potential effects on professional practice and health care outcomes. We have developed a Medline keyword search strategy, and this focused strategy will be translated into other databases. All search strategies will be provided in the review. The method proposed by the Cochrane EPOC group regarding randomized study designs, non-randomised controlled trials controlled before and after studies and interrupted time series will be followed. In addition, we will also include cohort, case–control studies, and relevant non-comparative publications such as case reports. We will categorize and analyse the review findings according to the study design employed, the study quality (low- versus high-quality studies) and the reported types of implementation in the primary studies. We will present the results of studies in a tabular form. Discussion Overall, the systematic review aims to identify, assess and synthesize the evidence to underpin the implementation of lean activities in health care settings as defined in this protocol. As a result, the review will provide an evidence base for the effectiveness of lean and implementation methodologies reported in health care. Systematic review registration PROSPERO CRD42014008853 PMID:25238974

  2. Methodological Considerations in Designing and Evaluating Animal-Assisted Interventions

    PubMed Central

    Stern, Cindy; Chur-Hansen, Anna

    2013-01-01

    Simple Summary There is a growing literature on the benefits of companion animals to human mental and physical health. Despite the literature base, these benefits are not well understood, because of flawed methodologies. This paper draws upon four systematic reviews, focusing exclusively on the use of canine-assisted interventions for older people residing in long-term care. Two guides are offered for researchers, one for qualitative research, one for quantitative studies, in order to improve the empirical basis of knowledge. Research in the area of the human-animal bond and the potential benefits that derive from it can be better promoted with the use of uniform and rigorous methodological approaches. Abstract This paper presents a discussion of the literature on animal-assisted interventions and describes limitations surrounding current methodological quality. Benefits to human physical, psychological and social health cannot be empirically confirmed due to the methodological limitations of the existing body of research, and comparisons cannot validly be made across different studies. Without a solid research base animal-assisted interventions will not receive recognition and acceptance as a credible alternative health care treatment. The paper draws on the work of four systematic reviews conducted over April–May 2009, with no date restrictions, focusing exclusively on the use of canine-assisted interventions for older people residing in long-term care. The reviews revealed a lack of good quality studies. Although the literature base has grown in volume since its inception, it predominantly consists of anecdotal accounts and reports. Experimental studies undertaken are often flawed in aspects of design, conduct and reporting. There are few qualitative studies available leading to the inability to draw definitive conclusions. It is clear that due to the complexities associated with these interventions not all weaknesses can be eliminated. However, there are

  3. The Use and Reporting of the Cross-Over Study Design in Clinical Trials and Systematic Reviews: A Systematic Assessment

    PubMed Central

    Hambleton, Ian; Dwan, Kerry

    2016-01-01

    Background Systematic reviews of treatment interventions in stable or chronic conditions often require the synthesis of clinical trials with a cross-over design. Previous work has indicated that methodology for analysing cross-over data is inadequate in trial reports and in systematic reviews assessing trials with this design. Objective We assessed systematic review methodology for synthesising cross-over trials among Cochrane Cystic Fibrosis and Genetic Disorders Group reviews published to July 2015, and assessed the quality of reporting among the cross-over trials included in these reviews. Methodology We performed data extraction of methodology and reporting in reviews, trials identified and trials included within reviews. Principal Findings We reviewed a total of 142 Cochrane systematic reviews including 53 reviews which synthesised evidence from 218 cross-over trials. Thirty-three (63%) Cochrane reviews described a clear and appropriate method for the inclusion of cross-over data, and of these 19 (56%) used the same method to analyse results. 145 cross-over trials were described narratively or treated as parallel trials in reviews but in 30 (21%) of these trials data existed in the trial reports to account for the cross-over design. At the trial level, the analysis and presentation of results were often inappropriate or unclear, with only 69 (32%) trials presenting results that could be included in meta-analysis. Conclusions Despite development of accessible, technical guidance and training for Cochrane systematic reviewers, statistical analysis and reporting of cross-over data is inadequate at both the systematic review and the trial level. Plain language and practical guidance for the inclusion of cross-over data in meta-analysis would benefit systematic reviewers, who come from a wide range of health specialties. Minimum reporting standards for cross-over trials are needed. PMID:27409076

  4. Environmental and Sustainability Education Policy Research: A Systematic Review of Methodological and Thematic Trends

    ERIC Educational Resources Information Center

    Aikens, Kathleen; McKenzie, Marcia; Vaughter, Philip

    2016-01-01

    This paper reports on a systematic literature review of policy research in the area of environmental and sustainability education. We analyzed 215 research articles, spanning four decades and representing 71 countries, and which engaged a range of methodologies. Our analysis combines quantification of geographic and methodological trends with…

  5. Unshrouded Centrifugal Turbopump Impeller Design Methodology

    NASA Technical Reports Server (NTRS)

    Prueger, George H.; Williams, Morgan; Chen, Wei-Chung; Paris, John; Williams, Robert; Stewart, Eric

    2001-01-01

    Turbopump weight continues to be a dominant parameter in the trade space for reduction of engine weight. Space Shuttle Main Engine weight distribution indicates that the turbomachinery make up approximately 30% of the total engine weight. Weight reduction can be achieved through the reduction of envelope of the turbopump. Reduction in envelope relates to an increase in turbopump speed and an increase in impeller head coefficient. Speed can be increased until suction performance limits are achieved on the pump or due to alternate constraints the turbine or bearings limit speed. Once the speed of the turbopump is set the impeller tip speed sets the minimum head coefficient of the machine. To reduce impeller diameter the head coefficient must be increased. A significant limitation with increasing head coefficient is that the slope of the head-flow characteristic is affected and this can limit engine throttling range. Unshrouded impellers offer a design option for increased turbopump speed without increasing the impeller head coefficient. However, there are several issues with regard to using an unshrouded impeller: there is a pump performance penalty due to the front open face recirculation flow, there is a potential pump axial thrust problem from the unbalanced front open face and the back shroud face, and since test data is very limited for this configuration, there is uncertainty in the magnitude and phase of the rotordynamic forces due to the front impeller passage. The purpose of the paper is to discuss the design of an unshrouded impeller and to examine the hydrodynamic performance, axial thrust, and rotordynamic performance. The design methodology will also be discussed. This work will help provide some guidelines for unshrouded impeller design.

  6. Methodologies and study designs relevant to medical education research.

    PubMed

    Turner, Teri L; Balmer, Dorene F; Coverdale, John H

    2013-06-01

    Research is an important part of educational scholarship. Knowledge of research methodologies is essential for both conducting research as well as determining the soundness of the findings from published studies. Our goals for this paper therefore are to inform medical education researchers of the range and key components of educational research designs. We will discuss both qualitative and quantitative approaches to educational research. Qualitative methods will be presented according to traditions that have a distinguished history in particular disciplines. Quantitative methods will be presented according to an evidence-based hierarchy akin to that of evidence-based medicine with the stronger designs (systematic reviews and well conducted educational randomized controlled trials) at the top, and weaker designs (descriptive studies without comparison groups, or single case studies) at the bottom. It should be appreciated, however, that the research question determines the study design. Therefore, the onus is on the researcher to choose a design that is appropriate to answering the question. We conclude with an overview of how educational researchers should describe the study design and methods in order to provide transparency and clarity. PMID:23859093

  7. New methodology for systematic construction of systolic arrays

    SciTech Connect

    Faroughi, N.

    1987-01-01

    Transforming an algorithm, represented by mathematical expressions with uniform and bounded index spaces, into a systolic-array architecture is discussed. Systolic arrays are highly structured architectures tailored to a specific application. They have specific architectural properties such as simple processing elements (cells), simple and regular data and control communication, and local-cell interconnections. The new design method is based on an understanding of the relationship between two highly structured representations of the algorithms: the mathematical expressions and their systolic solutions. The method consists of three major steps: algorithm representation, algorithm model, and architecture specification. The algorithm representation involves the translation of mathematical expressions into a set of equivalent simple computations which are grouped into subsets based on the required set of operations and same type operands. In the algorithm model, the properties of systolic arrays are represented in terms of feature interrelationships. A sub-systolic array is designed separately for each subset of the simple computations. The final array is constructed by joining the sub-systolic arrays. Other architecture specifications, such as data movement and cell count ratio, are determined early in a design process and thus can be used to select systolic solutions that require fewest cells and lowest I/O bandwidth.

  8. CONCEPTUAL DESIGNS FOR A NEW HIGHWAY VEHICLE EMISSIONS ESTIMATION METHODOLOGY

    EPA Science Inventory

    The report discusses six conceptual designs for a new highway vehicle emissions estimation methodology and summarizes the recommendations of each design for improving the emissions and activity factors in the emissions estimation process. he complete design reports are included a...

  9. Methodology for Preliminary Design of Electrical Microgrids

    SciTech Connect

    Jensen, Richard P.; Stamp, Jason E.; Eddy, John P.; Henry, Jordan M; Munoz-Ramos, Karina; Abdallah, Tarek

    2015-09-30

    Many critical loads rely on simple backup generation to provide electricity in the event of a power outage. An Energy Surety Microgrid TM can protect against outages caused by single generator failures to improve reliability. An ESM will also provide a host of other benefits, including integration of renewable energy, fuel optimization, and maximizing the value of energy storage. The ESM concept includes a categorization for microgrid value proposi- tions, and quantifies how the investment can be justified during either grid-connected or utility outage conditions. In contrast with many approaches, the ESM approach explic- itly sets requirements based on unlikely extreme conditions, including the need to protect against determined cyber adversaries. During the United States (US) Department of Defense (DOD)/Department of Energy (DOE) Smart Power Infrastructure Demonstration for Energy Reliability and Security (SPIDERS) effort, the ESM methodology was successfully used to develop the preliminary designs, which direct supported the contracting, construction, and testing for three military bases. Acknowledgements Sandia National Laboratories and the SPIDERS technical team would like to acknowledge the following for help in the project: * Mike Hightower, who has been the key driving force for Energy Surety Microgrids * Juan Torres and Abbas Akhil, who developed the concept of microgrids for military installations * Merrill Smith, U.S. Department of Energy SPIDERS Program Manager * Ross Roley and Rich Trundy from U.S. Pacific Command * Bill Waugaman and Bill Beary from U.S. Northern Command * Melanie Johnson and Harold Sanborn of the U.S. Army Corps of Engineers Construc- tion Engineering Research Laboratory * Experts from the National Renewable Energy Laboratory, Idaho National Laboratory, Oak Ridge National Laboratory, and Pacific Northwest National Laboratory

  10. Improving spacecraft design using a multidisciplinary design optimization methodology

    NASA Astrophysics Data System (ADS)

    Mosher, Todd Jon

    2000-10-01

    Spacecraft design has gone from maximizing performance under technology constraints to minimizing cost under performance constraints. This is characteristic of the "faster, better, cheaper" movement that has emerged within NASA. Currently spacecraft are "optimized" manually through a tool-assisted evaluation of a limited set of design alternatives. With this approach there is no guarantee that a systems-level focus will be taken and "feasibility" rather than "optimality" is commonly all that is achieved. To improve spacecraft design in the "faster, better, cheaper" era, a new approach using multidisciplinary design optimization (MDO) is proposed. Using MDO methods brings structure to conceptual spacecraft design by casting a spacecraft design problem into an optimization framework. Then, through the construction of a model that captures design and cost, this approach facilitates a quicker and more straightforward option synthesis. The final step is to automatically search the design space. As computer processor speed continues to increase, enumeration of all combinations, while not elegant, is one method that is straightforward to perform. As an alternative to enumeration, genetic algorithms are used and find solutions by reviewing fewer possible solutions with some limitations. Both methods increase the likelihood of finding an optimal design, or at least the most promising area of the design space. This spacecraft design methodology using MDO is demonstrated on three examples. A retrospective test for validation is performed using the Near Earth Asteroid Rendezvous (NEAR) spacecraft design. For the second example, the premise that aerobraking was needed to minimize mission cost and was mission enabling for the Mars Global Surveyor (MGS) mission is challenged. While one might expect no feasible design space for an MGS without aerobraking mission, a counterintuitive result is discovered. Several design options that don't use aerobraking are feasible and cost

  11. Systematic design of an anastigmatic lens axicon

    NASA Astrophysics Data System (ADS)

    Goncharov, Alexander V.; Burvall, Anna; Dainty, Christopher

    2007-08-01

    We present an analytical method for systematic optical design of a double-pass axicon that shows almost no astigmatism in oblique illumination compared to a conventional linear axicon. The anastigmatic axicon is a singlet lens with nearly concentric spherical surfaces applied in double pass, making it possible to form a long narrow focal line of uniform width. The front and the back surfaces have reflective coatings in the central and annular zones, respectively, to provide the double pass. Our design method finds the radii of curvatures and axial thickness of the lens for a given angle between the exiting rays and the optical axis. It also finds the optimal position of the reflecting zones for minimal vignetting. This method is based on ray tracing of the real rays at the marginal heights of the aperture and therefore is superior to any paraxial method. We illustrate the efficiency of the method by designing a test axicon with optical parameters used for a prototype axicon, which was manufactured and experimentally tested. We compare the optical characteristics of our test axicon with those of the experimental prototype.

  12. Enhancing the Front-End Phase of Design Methodology

    ERIC Educational Resources Information Center

    Elias, Erasto

    2006-01-01

    Design methodology (DM) is defined by the procedural path, expressed in design models, and techniques or methods used to untangle the various activities within a design model. Design education in universities is mainly based on descriptive design models. Much knowledge and organization have been built into DM to facilitate design teaching.…

  13. Design and Methodology in Institutional Research.

    ERIC Educational Resources Information Center

    Bagley, Clarence H., Ed.

    The proceedings of this forum contain 23 papers focusing mainly on the technical aspects of institutional research. Most of the authors are institutional research officers in various colleges and universities. Part 1 contains papers on institutional research methodology. They deal with such topics as faculty load studies, enrollment projections,…

  14. Technical report on LWR design decision methodology. Phase I

    SciTech Connect

    1980-03-01

    Energy Incorporated (EI) was selected by Sandia Laboratories to develop and test on LWR design decision methodology. Contract Number 42-4229 provided funding for Phase I of this work. This technical report on LWR design decision methodology documents the activities performed under that contract. Phase I was a short-term effort to thoroughly review the curret LWR design decision process to assure complete understanding of current practices and to establish a well defined interface for development of initial quantitative design guidelines.

  15. Systematic risk assessment methodology for critical infrastructure elements - Oil and Gas subsectors

    NASA Astrophysics Data System (ADS)

    Gheorghiu, A.-D.; Ozunu, A.

    2012-04-01

    The concern for the protection of critical infrastructure has been rapidly growing in the last few years in Europe. The level of knowledge and preparedness in this field is beginning to develop in a lawfully organized manner, for the identification and designation of critical infrastructure elements of national and European interest. Oil and gas production, refining, treatment, storage and transmission by pipelines facilities, are considered European critical infrastructure sectors, as per Annex I of the Council Directive 2008/114/EC of 8 December 2008 on the identification and designation of European critical infrastructures and the assessment of the need to improve their protection. Besides identifying European and national critical infrastructure elements, member states also need to perform a risk analysis for these infrastructure items, as stated in Annex II of the above mentioned Directive. In the field of risk assessment, there are a series of acknowledged and successfully used methods in the world, but not all hazard identification and assessment methods and techniques are suitable for a given site, situation, or type of hazard. As Theoharidou, M. et al. noted (Theoharidou, M., P. Kotzanikolaou, and D. Gritzalis 2009. Risk-Based Criticality Analysis. In Critical Infrastructure Protection III. Proceedings. Third Annual IFIP WG 11.10 International Conference on Critical Infrastructure Protection. Hanover, New Hampshire, USA, March 23-25, 2009: revised selected papers, edited by C. Palmer and S. Shenoi, 35-49. Berlin: Springer.), despite the wealth of knowledge already created, there is a need for simple, feasible, and standardized criticality analyses. The proposed systematic risk assessment methodology includes three basic steps: the first step (preliminary analysis) includes the identification of hazards (including possible natural hazards) for each installation/section within a given site, followed by a criterial analysis and then a detailed analysis step

  16. Reporting of results from network meta-analyses: methodological systematic review

    PubMed Central

    Trinquart, Ludovic; Seror, Raphaèle; Ravaud, Philippe

    2014-01-01

    Objective To examine how the results of network meta-analyses are reported. Design Methodological systematic review of published reports of network meta-analyses. Data sources Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Medline, and Embase, searched from inception to 12 July 2012. Study selection All network meta-analyses comparing the clinical efficacy of three or more interventions in randomised controlled trials were included, excluding meta-analyses with an open loop network of three interventions. Data extraction and synthesis The reporting of the network and results was assessed. A composite outcome included the description of the network (number of interventions, direct comparisons, and randomised controlled trials and patients for each comparison) and the reporting of effect sizes derived from direct evidence, indirect evidence, and the network meta-analysis. Results 121 network meta-analyses (55 published in general journals; 48 funded by at least one private source) were included. The network and its geometry (network graph) were not reported in 100 (83%) articles. The effect sizes derived from direct evidence, indirect evidence, and the network meta-analysis were not reported in 48 (40%), 108 (89%), and 43 (36%) articles, respectively. In 52 reports that ranked interventions, 43 did not report the uncertainty in ranking. Overall, 119 (98%) reports of network meta-analyses did not give a description of the network or effect sizes from direct evidence, indirect evidence, and the network meta-analysis. This finding did not differ by journal type or funding source. Conclusions The results of network meta-analyses are heterogeneously reported. Development of reporting guidelines to assist authors in writing and readers in critically appraising reports of network meta-analyses is timely. PMID:24618053

  17. Methodology used in studies reporting chronic kidney disease prevalence: a systematic literature review

    PubMed Central

    Brück, Katharina; Jager, Kitty J.; Dounousi, Evangelia; Kainz, Alexander; Nitsch, Dorothea; Ärnlöv, Johan; Rothenbacher, Dietrich; Browne, Gemma; Capuano, Vincenzo; Ferraro, Pietro Manuel; Ferrieres, Jean; Gambaro, Giovanni; Guessous, Idris; Hallan, Stein; Kastarinen, Mika; Navis, Gerjan; Gonzalez, Alfonso Otero; Palmieri, Luigi; Romundstad, Solfrid; Spoto, Belinda; Stengel, Benedicte; Tomson, Charles; Tripepi, Giovanni; Völzke, Henry; Wiȩcek, Andrzej; Gansevoort, Ron; Schöttker, Ben; Wanner, Christoph; Vinhas, Jose; Zoccali, Carmine; Van Biesen, Wim; Stel, Vianda S.

    2015-01-01

    Background Many publications report the prevalence of chronic kidney disease (CKD) in the general population. Comparisons across studies are hampered as CKD prevalence estimations are influenced by study population characteristics and laboratory methods. Methods For this systematic review, two researchers independently searched PubMed, MEDLINE and EMBASE to identify all original research articles that were published between 1 January 2003 and 1 November 2014 reporting the prevalence of CKD in the European adult general population. Data on study methodology and reporting of CKD prevalence results were independently extracted by two researchers. Results We identified 82 eligible publications and included 48 publications of individual studies for the data extraction. There was considerable variation in population sample selection. The majority of studies did not report the sampling frame used, and the response ranged from 10 to 87%. With regard to the assessment of kidney function, 67% used a Jaffe assay, whereas 13% used the enzymatic assay for creatinine determination. Isotope dilution mass spectrometry calibration was used in 29%. The CKD-EPI (52%) and MDRD (75%) equations were most often used to estimate glomerular filtration rate (GFR). CKD was defined as estimated GFR (eGFR) <60 mL/min/1.73 m2 in 92% of studies. Urinary markers of CKD were assessed in 60% of the studies. CKD prevalence was reported by sex and age strata in 54 and 50% of the studies, respectively. In publications with a primary objective of reporting CKD prevalence, 39% reported a 95% confidence interval. Conclusions The findings from this systematic review showed considerable variation in methods for sampling the general population and assessment of kidney function across studies reporting CKD prevalence. These results are utilized to provide recommendations to help optimize both the design and the reporting of future CKD prevalence studies, which will enhance comparability of study results

  18. Forced vibration and flutter design methodology

    SciTech Connect

    Snyder, L.E.; Burns, D.W.

    1988-06-01

    The aeroelastic principles and considerations of designing blades, disks, and vanes to avoid high cycle fatigue failure is covered. Two types of vibration that can cause high cycle fatigue, flutter, and forced vibration, will first be defined and the basic governing equations discussed. Next, under forced vibration design the areas of source definition, types of components, vibratory mode shape definitions, and basic steps in design for adequate high cycle fatigue life will be presented. For clarification a forced vibration design example will be shown using a high performance turbine blade/disk component. Finally, types of flutter, dominant flutter parameters, and flutter procedures and design parameters will be discussed. The overall emphasis is on application to initial design of blades, disks, and vanes of aeroelastic criteria to prevent high cycle fatigue failures.

  19. The Study of the Relationship between Probabilistic Design and Axiomatic Design Methodology. Volume 1

    NASA Technical Reports Server (NTRS)

    Onwubiko, Chinyere; Onyebueke, Landon

    1996-01-01

    This program report is the final report covering all the work done on this project. The goal of this project is technology transfer of methodologies to improve design process. The specific objectives are: 1. To learn and understand the Probabilistic design analysis using NESSUS. 2. To assign Design Projects to either undergraduate or graduate students on the application of NESSUS. 3. To integrate the application of NESSUS into some selected senior level courses in Civil and Mechanical Engineering curricula. 4. To develop courseware in Probabilistic Design methodology to be included in a graduate level Design Methodology course. 5. To study the relationship between the Probabilistic design methodology and Axiomatic design methodology.

  20. A prototype computerized synthesis methodology for generic space access vehicle (SAV) conceptual design

    NASA Astrophysics Data System (ADS)

    Huang, Xiao

    2006-04-01

    Today's and especially tomorrow's competitive launch vehicle design environment requires the development of a dedicated generic Space Access Vehicle (SAV) design methodology. A total of 115 industrial, research, and academic aircraft, helicopter, missile, and launch vehicle design synthesis methodologies have been evaluated. As the survey indicates, each synthesis methodology tends to focus on a specific flight vehicle configuration, thus precluding the key capability to systematically compare flight vehicle design alternatives. The aim of the research investigation is to provide decision-making bodies and the practicing engineer a design process and tool box for robust modeling and simulation of flight vehicles where the ultimate performance characteristics may hinge on numerical subtleties. This will enable the designer of a SAV for the first time to consistently compare different classes of SAV configurations on an impartial basis. This dissertation presents the development steps required towards a generic (configuration independent) hands-on flight vehicle conceptual design synthesis methodology. This process is developed such that it can be applied to any flight vehicle class if desired. In the present context, the methodology has been put into operation for the conceptual design of a tourist Space Access Vehicle. The case study illustrates elements of the design methodology & algorithm for the class of Horizontal Takeoff and Horizontal Landing (HTHL) SAVs. The HTHL SAV design application clearly outlines how the conceptual design process can be centrally organized, executed and documented with focus on design transparency, physical understanding and the capability to reproduce results. This approach offers the project lead and creative design team a management process and tool which iteratively refines the individual design logic chosen, leading to mature design methods and algorithms. As illustrated, the HTHL SAV hands-on design methodology offers growth

  1. Qualitative research synthesis: methodological guidance for systematic reviewers utilizing meta-aggregation.

    PubMed

    Lockwood, Craig; Munn, Zachary; Porritt, Kylie

    2015-09-01

    Qualitative synthesis informs important aspects of evidence-based healthcare, particularly within the practical decision-making contexts that health professionals work in. Of the qualitative methodologies available for synthesis, meta-aggregation is most transparently aligned with accepted conventions for the conduct of high-quality systematic reviews. Meta-aggregation is philosophically grounded in pragmatism and transcendental phenomenology. The essential characteristics of a meta-aggregative review are that the reviewer avoids re-interpretation of included studies, but instead accurately and reliably presents the findings of the included studies as intended by the original authors. This study reports on the methodology and methods of meta-aggregation within the structure of an a priori protocol and standardized frameworks for reporting of results by over-viewing the essential components of a systematic review report. PMID:26262565

  2. Implicit Shape Parameterization for Kansei Design Methodology

    NASA Astrophysics Data System (ADS)

    Nordgren, Andreas Kjell; Aoyama, Hideki

    Implicit shape parameterization for Kansei design is a procedure that use 3D-models, or concepts, to span a shape space for surfaces in the automotive field. A low-dimensional, yet accurate shape descriptor was found by Principal Component Analysis of an ensemble of point-clouds, which were extracted from mesh-based surfaces modeled in a CAD-program. A theoretical background of the procedure is given along with step-by-step instructions for the required data-processing. The results show that complex surfaces can be described very efficiently, and encode design features by an implicit approach that does not rely on error-prone explicit parameterizations. This provides a very intuitive way to explore shapes for a designer, because various design features can simply be introduced by adding new concepts to the ensemble. Complex shapes have been difficult to analyze with Kansei methods due to the large number of parameters involved, but implicit parameterization of design features provides a low-dimensional shape descriptor for efficient data collection, model-building and analysis of emotional content in 3D-surfaces.

  3. A wing design methodology for low-boom low-drag supersonic business jet

    NASA Astrophysics Data System (ADS)

    Le, Daniel B.

    2009-12-01

    The arguably most critical hindrance to the successful development of a commercial supersonic aircraft is the impact of the sonic boom signature. The sonic boom signature of a supersonic aircraft is predicted using sonic boom theory, which formulates a relationship between the complex three-dimensional geometry of the aircraft to the pressure distribution and decomposes the geometry in terms of simple geometrical components. The supersonic aircraft design process is typically based on boom minimization theory. This theory provides a theoretical equivalent area distribution which should be matched by the conceptual design in order to achieve the pre-determined sonic boom signature. The difference between the target equivalent area distribution and the actual equivalent area distribution is referred to here as the gap distribution. The primary intent of this dissertation is to provide the designer with a systematic and structured approach to designing the aircraft wings with limited changes to the baseline concept while achieving critical design goals. The design process can be easily overwhelmed and may be difficult to evaluate their effectiveness. The wing design is decoupled into two separate processes, one focused on the planform design and the other on the camber design. Moreover, this design methodology supplements the designer by allowing trade studies to be conducted between important design parameters and objectives. The wing planform design methodology incorporates a continuous gradient-based optimization scheme to supplement the design process. This is not meant to substitute the vast amount of knowledge and design decisions that are needed for a successful design. Instead, the numerical optimization helps the designer to refine creative concepts. Last, this dissertation integrates a risk mitigation scheme throughout the wing design process. The design methodology implements minimal design changes to the wing geometry white achieving the target design goal

  4. Philosophical and Methodological Beliefs of Instructional Design Faculty and Professionals

    ERIC Educational Resources Information Center

    Sheehan, Michael D.; Johnson, R. Burke

    2012-01-01

    The purpose of this research was to probe the philosophical beliefs of instructional designers using sound philosophical constructs and quantitative data collection and analysis. We investigated the philosophical and methodological beliefs of instructional designers, including 152 instructional design faculty members and 118 non-faculty…

  5. Experimental Validation of an Integrated Controls-Structures Design Methodology

    NASA Technical Reports Server (NTRS)

    Maghami, Peiman G.; Gupta, Sandeep; Elliot, Kenny B.; Walz, Joseph E.

    1996-01-01

    The first experimental validation of an integrated controls-structures design methodology for a class of large order, flexible space structures is described. Integrated redesign of the controls-structures-interaction evolutionary model, a laboratory testbed at NASA Langley, was described earlier. The redesigned structure was fabricated, assembled in the laboratory, and experimentally tested against the original structure. Experimental results indicate that the structure redesigned using the integrated design methodology requires significantly less average control power than the nominal structure with control-optimized designs, while maintaining the required line-of-sight pointing performance. Thus, the superiority of the integrated design methodology over the conventional design approach is experimentally demonstrated. Furthermore, amenability of the integrated design structure to other control strategies is evaluated, both analytically and experimentally. Using Linear-Quadratic-Guassian optimal dissipative controllers, it is observed that the redesigned structure leads to significantly improved performance with alternate controllers as well.

  6. Changes in Clinical Trials Methodology Over Time: A Systematic Review of Six Decades of Research in Psychopharmacology

    PubMed Central

    Brunoni, André R.; Tadini, Laura; Fregni, Felipe

    2010-01-01

    Background There have been many changes in clinical trials methodology since the introduction of lithium and the beginning of the modern era of psychopharmacology in 1949. The nature and importance of these changes have not been fully addressed to date. As methodological flaws in trials can lead to false-negative or false-positive results, the objective of our study was to evaluate the impact of methodological changes in psychopharmacology clinical research over the past 60 years. Methodology/Principal Findings We performed a systematic review from 1949 to 2009 on MEDLINE and Web of Science electronic databases, and a hand search of high impact journals on studies of seven major drugs (chlorpromazine, clozapine, risperidone, lithium, fluoxetine and lamotrigine). All controlled studies published 100 months after the first trial were included. Ninety-one studies met our inclusion criteria. We analyzed the major changes in abstract reporting, study design, participants' assessment and enrollment, methodology and statistical analysis. Our results showed that the methodology of psychiatric clinical trials changed substantially, with quality gains in abstract reporting, results reporting, and statistical methodology. Recent trials use more informed consent, periods of washout, intention-to-treat approach and parametric tests. Placebo use remains high and unchanged over time. Conclusions/Significance Clinical trial quality of psychopharmacological studies has changed significantly in most of the aspects we analyzed. There was significant improvement in quality reporting and internal validity. These changes have increased study efficiency; however, there is room for improvement in some aspects such as rating scales, diagnostic criteria and better trial reporting. Therefore, despite the advancements observed, there are still several areas that can be improved in psychopharmacology clinical trials. PMID:20209133

  7. Surface design methodology - challenge the steel

    NASA Astrophysics Data System (ADS)

    Bergman, M.; Rosen, B.-G.; Eriksson, L.; Anderberg, C.

    2014-03-01

    The way a product or material is experienced by its user could be different depending on the scenario. It is also well known that different materials and surfaces are used for different purposes. When optimizing materials and surface roughness for a certain something with the intention to improve a product, it is important to obtain not only the physical requirements, but also the user experience and expectations. Laws and requirements of the materials and the surface function, but also the conservative way of thinking about materials and colours characterize the design of medical equipment. The purpose of this paper is to link the technical- and customer requirements of current materials and surface textures in medical environments. By focusing on parts of the theory of Kansei Engineering, improvements of the companys' products are possible. The idea is to find correlations between desired experience or "feeling" for a product, -customer requirements, functional requirements, and product geometrical properties -design parameters, to be implemented on new improved products. To be able to find new materials with the same (or better) technical requirements but a higher level of user stimulation, the current material (stainless steel) and its surface (brushed textures) was used as a reference. The usage of focus groups of experts at the manufacturer lead to a selection of twelve possible new materials for investigation in the project. In collaboration with the topical company for this project, three new materials that fulfil the requirements -easy to clean and anti-bacterial came to be in focus for further investigation in regard to a new design of a washer-disinfector for medical equipment using the Kansei based Clean ability approach CAA.

  8. FOREWORD: Computational methodologies for designing materials Computational methodologies for designing materials

    NASA Astrophysics Data System (ADS)

    Rahman, Talat S.

    2009-02-01

    It would be fair to say that in the past few decades, theory and computer modeling have played a major role in elucidating the microscopic factors that dictate the properties of functional novel materials. Together with advances in experimental techniques, theoretical methods are becoming increasingly capable of predicting properties of materials at different length scales, thereby bringing in sight the long-sought goal of designing material properties according to need. Advances in computer technology and their availability at a reasonable cost around the world have made tit all the more urgent to disseminate what is now known about these modern computational techniques. In this special issue on computational methodologies for materials by design we have tried to solicit articles from authors whose works collectively represent the microcosm of developments in the area. This turned out to be a difficult task for a variety of reasons, not the least of which is space limitation in this special issue. Nevertheless, we gathered twenty articles that represent some of the important directions in which theory and modeling are proceeding in the general effort to capture the ability to produce materials by design. The majority of papers presented here focus on technique developments that are expected to uncover further the fundamental processes responsible for material properties, and for their growth modes and morphological evolutions. As for material properties, some of the articles here address the challenges that continue to emerge from attempts at accurate descriptions of magnetic properties, of electronically excited states, and of sparse matter, all of which demand new looks at density functional theory (DFT). I should hasten to add that much of the success in accurate computational modeling of materials emanates from the remarkable predictive power of DFT, without which we would not be able to place the subject on firm theoretical grounds. As we know and will also

  9. A Methodology for the Neutronics Design of Space Nuclear Reactors

    SciTech Connect

    King, Jeffrey C.; El-Genk, Mohamed S.

    2004-02-04

    A methodology for the neutronics design of space power reactors is presented. This methodology involves balancing the competing requirements of having sufficient excess reactivity for the desired lifetime, keeping the reactor subcritical at launch and during submersion accidents, and providing sufficient control over the lifetime of the reactor. These requirements are addressed by three reactivity values for a given reactor design: the excess reactivity at beginning of mission, the negative reactivity at shutdown, and the negative reactivity margin in submersion accidents. These reactivity values define the control worth and the safety worth in submersion accidents, used for evaluating the merit of a proposed reactor type and design. The Heat Pipe-Segmented Thermoelectric Module Converters space reactor core design is evaluated and modified based on the proposed methodology. The final reactor core design has sufficient excess reactivity for 10 years of nominal operation at 1.82 MW of fission power and is subcritical at launch and in all water submersion accidents.

  10. Optimization Methodology for Unconventional Rocket Nozzle Design

    NASA Technical Reports Server (NTRS)

    Follett, W.

    1996-01-01

    Several current rocket engine concepts such as the bell-annular tripropellant engine, and the linear aerospike being proposed for the X-33, require unconventional three-dimensional rocket nozzles which must conform to rectangular or sector-shaped envelopes to meet integration constraints. These types of nozzles exist outside the current experience database, therefore, development of efficient design methods for these propulsion concepts is critical to the success of launch vehicle programs. Several approaches for optimizing rocket nozzles, including streamline tracing techniques, and the coupling of CFD analysis to optimization algorithms are described. The relative strengths and weaknesses of four classes of optimization algorithms are discussed: Gradient based methods, genetic algorithms, simplex methods, and surface response methods. Additionally, a streamline tracing technique, which provides a very computationally efficient means of defining a three-dimensional contour, is discussed. The performance of the various optimization methods on thrust optimization problems for tripropellant and aerospike concepts is assessed and recommendations are made for future development efforts.

  11. Solid lubrication design methodology, phase 2

    NASA Technical Reports Server (NTRS)

    Pallini, R. A.; Wedeven, L. D.; Ragen, M. A.; Aggarwal, B. B.

    1986-01-01

    The high temperature performance of solid lubricated rolling elements was conducted with a specially designed traction (friction) test apparatus. Graphite lubricants containing three additives (silver, phosphate glass, and zinc orthophosphate) were evaluated from room temperature to 540 C. Two hard coats were also evaluated. The evaluation of these lubricants, using a burnishing method of application, shows a reasonable transfer of lubricant and wear protection for short duration testing except in the 200 C temperature range. The graphite lubricants containing silver and zinc orthophosphate additives were more effective than the phosphate glass material over the test conditions examined. Traction coefficients ranged from a low of 0.07 to a high of 0.6. By curve fitting the traction data, empirical equations for slope and maximum traction coefficient as a function of contact pressure (P), rolling speed (U), and temperature (T) can be developed for each lubricant. A solid lubricant traction model was incorporated into an advanced bearing analysis code (SHABERTH). For comparison purposes, preliminary heat generation calculations were made for both oil and solid lubricated bearing operation. A preliminary analysis indicated a significantly higher heat generation for a solid lubricated ball bearing in a deep groove configuration. An analysis of a cylindrical roller bearing configuration showed a potential for a low friction solid lubricated bearing.

  12. Fast detection of manufacturing systematic design pattern failures causing device yield loss

    NASA Astrophysics Data System (ADS)

    Le Denmat, Jean-Christophe; Feldman, Nelly; Riewer, Olivia; Yesilada, Emek; Vallet, Michel; Suzor, Christophe; Talluto, Salvatore

    2015-03-01

    Starting from the 45nm technology node, systematic defectivity has a significant impact on device yield loss with each new technology node. The effort required to achieve patterning maturity with zero yield detractor is also significantly increasing with technology nodes. Within the manufacturing environment, new in-line wafer inspection methods have been developed to identify device systematic defects, including the process window qualification (PWQ) methodology used to characterize process robustness. Although patterning is characterized with PWQ methodology, some questions remain: How can we demonstrate that the measured process window is large enough to avoid design-based defects which will impact the device yield? Can we monitor the systematic yield loss on nominal wafers? From device test engineering point of view, systematic yield detractors are expected to be identified by Automated Test Pattern Generator (ATPG) test results diagnostics performed after electrical wafer sort (EWS). Test diagnostics can identify failed nets or cells causing systematic yield loss [1],[2]. Convergence from device failed nets and cells to failed manufacturing design pattern are usually based on assumptions that should be confirmed by an electrical failure analysis (EFA). However, many EFA investigations are required before the design pattern failures are found, and thus design pattern failure identification was costly in time and resources. With this situation, an opportunity to share knowledge exists between device test engineering and manufacturing environments to help with device yield improvement. This paper presents a new yield diagnostics flow dedicated to correlation of critical design patterns detected within manufacturing environment, with the observed device yield loss. The results obtained with this new flow on a 28nm technology device are described, with the defects of interest and the device yield impact for each design pattern. The EFA done to validate the design

  13. A methodological survey of the analysis, reporting and interpretation of Absolute Risk ReductiOn in systematic revieWs (ARROW): a study protocol

    PubMed Central

    2013-01-01

    Background Clinicians, providers and guideline panels use absolute effects to weigh the advantages and downsides of treatment alternatives. Relative measures have the potential to mislead readers. However, little is known about the reporting of absolute measures in systematic reviews. The objectives of our study are to determine the proportion of systematic reviews that report absolute measures of effect for the most important outcomes, and ascertain how they are analyzed, reported and interpreted. Methods/design We will conduct a methodological survey of systematic reviews published in 2010. We will conduct a 1:1 stratified random sampling of Cochrane vs. non-Cochrane systematic reviews. We will calculate the proportion of systematic reviews reporting at least one absolute estimate of effect for the most patient-important outcome for the comparison of interest. We will conduct multivariable logistic regression analyses with the reporting of an absolute estimate of effect as the dependent variable and pre-specified study characteristics as the independent variables. For systematic reviews reporting an absolute estimate of effect, we will document the methods used for the analysis, reporting and interpretation of the absolute estimate. Discussion Our methodological survey will inform current practices regarding reporting of absolute estimates in systematic reviews. Our findings may influence recommendations on reporting, conduct and interpretation of absolute estimates. Our results are likely to be of interest to systematic review authors, funding agencies, clinicians, guideline developers and journal editors. PMID:24330779

  14. SYSTEMATIC PROCEDURE FOR DESIGNING PROCESSES WITH MULTIPLE ENVIRONMENTAL OBJECTIVES

    EPA Science Inventory

    Evaluation of multiple objectives is very important in designing environmentally benign processes. It requires a systematic procedure for solving multiobjective decision-making problems, due to the complex nature of the problems, the need for complex assessments, and complicated ...

  15. PEM Fuel Cells Redesign Using Biomimetic and TRIZ Design Methodologies

    NASA Astrophysics Data System (ADS)

    Fung, Keith Kin Kei

    Two formal design methodologies, biomimetic design and the Theory of Inventive Problem Solving, TRIZ, were applied to the redesign of a Proton Exchange Membrane (PEM) fuel cell. Proof of concept prototyping was performed on two of the concepts for water management. The liquid water collection with strategically placed wicks concept demonstrated the potential benefits for a fuel cell. Conversely, the periodic flow direction reversal concepts might cause a potential reduction water removal from a fuel cell. The causes of this water removal reduction remain unclear. In additional, three of the concepts generated with biomimetic design were further studied and demonstrated to stimulate more creative ideas in the thermal and water management of fuel cells. The biomimetic design and the TRIZ methodologies were successfully applied to fuel cells and provided different perspectives to the redesign of fuel cells. The methodologies should continue to be used to improve fuel cells.

  16. Methodological Innovation in Practice-Based Design Doctorates

    ERIC Educational Resources Information Center

    Yee, Joyce S. R.

    2010-01-01

    This article presents a selective review of recent design PhDs that identify and analyse the methodological innovation that is occurring in the field, in order to inform future provision of research training. Six recently completed design PhDs are used to highlight possible philosophical and practical models that can be adopted by future PhD…

  17. Helicopter-V/STOL dynamic wind and turbulence design methodology

    NASA Technical Reports Server (NTRS)

    Bailey, J. Earl

    1987-01-01

    Aircraft and helicopter accidents due to severe dynamic wind and turbulence continue to present challenging design problems. The development of the current set of design analysis tools for a aircraft wind and turbulence design began in the 1940's and 1950's. The areas of helicopter dynamic wind and turbulence modeling and vehicle response to severe dynamic wind inputs (microburst type phenomena) during takeoff and landing remain as major unsolved design problems from a lack of both environmental data and computational methodology. The development of helicopter and V/STOL dynamic wind and turbulence response computation methology is reviewed, the current state of the design art in industry is outlined, and comments on design methodology are made which may serve to improve future flight vehicle design.

  18. Application of an Integrated Methodology for Propulsion and Airframe Control Design to a STOVL Aircraft

    NASA Technical Reports Server (NTRS)

    Garg, Sanjay; Mattern, Duane

    1994-01-01

    An advanced methodology for integrated flight propulsion control (IFPC) design for future aircraft, which will use propulsion system generated forces and moments for enhanced maneuver capabilities, is briefly described. This methodology has the potential to address in a systematic manner the coupling between the airframe and the propulsion subsystems typical of such enhanced maneuverability aircraft. Application of the methodology to a short take-off vertical landing (STOVL) aircraft in the landing approach to hover transition flight phase is presented with brief description of the various steps in the IFPC design methodology. The details of the individual steps have been described in previous publications and the objective of this paper is to focus on how the components of the control system designed at each step integrate into the overall IFPC system. The full nonlinear IFPC system was evaluated extensively in nonreal-time simulations as well as piloted simulations. Results from the nonreal-time evaluations are presented in this paper. Lessons learned from this application study are summarized in terms of areas of potential improvements in the STOVL IFPC design as well as identification of technology development areas to enhance the applicability of the proposed design methodology.

  19. Methodologies for measuring travelers' risk perception of infectious diseases: A systematic review.

    PubMed

    Sridhar, Shruti; Régner, Isabelle; Brouqui, Philippe; Gautret, Philippe

    2016-01-01

    Numerous studies in the past have stressed the importance of travelers' psychology and perception in the implementation of preventive measures. The aim of this systematic review was to identify the methodologies used in studies reporting on travelers' risk perception of infectious diseases. A systematic search for relevant literature was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. There were 39 studies identified. In 35 of 39 studies, the methodology used was that of a knowledge, attitude and practice (KAP) survey based on questionnaires. One study used a combination of questionnaires and a visual psychometric measuring instrument called the 'pictorial representation of illness and self-measurement" or PRISM. One study used a self-representation model (SRM) method. Two studies measured psychosocial factors. Valuable information was obtained from KAP surveys showing an overall lack of knowledge among travelers about the most frequent travel-associated infections and associated preventive measures. This methodological approach however, is mainly descriptive, addressing knowledge, attitudes, and practices separately and lacking an examination of the interrelationships between these three components. Another limitation of the KAP method is underestimating psychosocial variables that have proved influential in health related behaviors, including perceived benefits and costs of preventive measures, perceived social pressure, perceived personal control, unrealistic optimism and risk propensity. Future risk perception studies in travel medicine should consider psychosocial variables with inferential and multivariate statistical analyses. The use of implicit measurements of attitudes could also provide new insights in the field of travelers' risk perception of travel-associated infectious diseases. PMID:27238906

  20. A methodology for designing aircraft to low sonic boom constraints

    NASA Technical Reports Server (NTRS)

    Mack, Robert J.; Needleman, Kathy E.

    1991-01-01

    A method for designing conceptual supersonic cruise aircraft to meet low sonic boom requirements is outlined and described. The aircraft design is guided through a systematic evolution from initial three view drawing to a final numerical model description, while the designer using the method controls the integration of low sonic boom, high supersonic aerodynamic efficiency, adequate low speed handling, and reasonable structure and materials technologies. Some experience in preliminary aircraft design and in the use of various analytical and numerical codes is required for integrating the volume and lift requirements throughout the design process.

  1. External validation of multivariable prediction models: a systematic review of methodological conduct and reporting

    PubMed Central

    2014-01-01

    Background Before considering whether to use a multivariable (diagnostic or prognostic) prediction model, it is essential that its performance be evaluated in data that were not used to develop the model (referred to as external validation). We critically appraised the methodological conduct and reporting of external validation studies of multivariable prediction models. Methods We conducted a systematic review of articles describing some form of external validation of one or more multivariable prediction models indexed in PubMed core clinical journals published in 2010. Study data were extracted in duplicate on design, sample size, handling of missing data, reference to the original study developing the prediction models and predictive performance measures. Results 11,826 articles were identified and 78 were included for full review, which described the evaluation of 120 prediction models. in participant data that were not used to develop the model. Thirty-three articles described both the development of a prediction model and an evaluation of its performance on a separate dataset, and 45 articles described only the evaluation of an existing published prediction model on another dataset. Fifty-seven percent of the prediction models were presented and evaluated as simplified scoring systems. Sixteen percent of articles failed to report the number of outcome events in the validation datasets. Fifty-four percent of studies made no explicit mention of missing data. Sixty-seven percent did not report evaluating model calibration whilst most studies evaluated model discrimination. It was often unclear whether the reported performance measures were for the full regression model or for the simplified models. Conclusions The vast majority of studies describing some form of external validation of a multivariable prediction model were poorly reported with key details frequently not presented. The validation studies were characterised by poor design, inappropriate handling

  2. Enhancing Instructional Design Efficiency: Methodologies Employed by Instructional Designers

    ERIC Educational Resources Information Center

    Roytek, Margaret A.

    2010-01-01

    Instructional systems design (ISD) has been frequently criticised as taking too long to implement, calling for a reduction in cycle time--the time that elapses between project initiation and delivery. While instructional design research has historically focused on increasing "learner" efficiencies, the study of what instructional designers do to…

  3. A design methodology for nonlinear systems containing parameter uncertainty: Application to nonlinear controller design

    NASA Technical Reports Server (NTRS)

    Young, G.

    1982-01-01

    A design methodology capable of dealing with nonlinear systems, such as a controlled ecological life support system (CELSS), containing parameter uncertainty is discussed. The methodology was applied to the design of discrete time nonlinear controllers. The nonlinear controllers can be used to control either linear or nonlinear systems. Several controller strategies are presented to illustrate the design procedure.

  4. Variance estimation for systematic designs in spatial surveys.

    PubMed

    Fewster, R M

    2011-12-01

    In spatial surveys for estimating the density of objects in a survey region, systematic designs will generally yield lower variance than random designs. However, estimating the systematic variance is well known to be a difficult problem. Existing methods tend to overestimate the variance, so although the variance is genuinely reduced, it is over-reported, and the gain from the more efficient design is lost. The current approaches to estimating a systematic variance for spatial surveys are to approximate the systematic design by a random design, or approximate it by a stratified design. Previous work has shown that approximation by a random design can perform very poorly, while approximation by a stratified design is an improvement but can still be severely biased in some situations. We develop a new estimator based on modeling the encounter process over space. The new "striplet" estimator has negligible bias and excellent precision in a wide range of simulation scenarios, including strip-sampling, distance-sampling, and quadrat-sampling surveys, and including populations that are highly trended or have strong aggregation of objects. We apply the new estimator to survey data for the spotted hyena (Crocuta crocuta) in the Serengeti National Park, Tanzania, and find that the reported coefficient of variation for estimated density is 20% using approximation by a random design, 17% using approximation by a stratified design, and 11% using the new striplet estimator. This large reduction in reported variance is verified by simulation. PMID:21534940

  5. A Practical Methodology for Quantifying Random and Systematic Components of Unexplained Variance in a Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Deloach, Richard; Obara, Clifford J.; Goodman, Wesley L.

    2012-01-01

    This paper documents a check standard wind tunnel test conducted in the Langley 0.3-Meter Transonic Cryogenic Tunnel (0.3M TCT) that was designed and analyzed using the Modern Design of Experiments (MDOE). The test designed to partition the unexplained variance of typical wind tunnel data samples into two constituent components, one attributable to ordinary random error, and one attributable to systematic error induced by covariate effects. Covariate effects in wind tunnel testing are discussed, with examples. The impact of systematic (non-random) unexplained variance on the statistical independence of sequential measurements is reviewed. The corresponding correlation among experimental errors is discussed, as is the impact of such correlation on experimental results generally. The specific experiment documented herein was organized as a formal test for the presence of unexplained variance in representative samples of wind tunnel data, in order to quantify the frequency with which such systematic error was detected, and its magnitude relative to ordinary random error. Levels of systematic and random error reported here are representative of those quantified in other facilities, as cited in the references.

  6. Prognostics and health management design for rotary machinery systems—Reviews, methodology and applications

    NASA Astrophysics Data System (ADS)

    Lee, Jay; Wu, Fangji; Zhao, Wenyu; Ghaffari, Masoud; Liao, Linxia; Siegel, David

    2014-01-01

    Much research has been conducted in prognostics and health management (PHM), an emerging field in mechanical engineering that is gaining interest from both academia and industry. Most of these efforts have been in the area of machinery PHM, resulting in the development of many algorithms for this particular application. The majority of these algorithms concentrate on applications involving common rotary machinery components, such as bearings and gears. Knowledge of this prior work is a necessity for any future research efforts to be conducted; however, there has not been a comprehensive overview that details previous and on-going efforts in PHM. In addition, a systematic method for developing and deploying a PHM system has yet to be established. Such a method would enable rapid customization and integration of PHM systems for diverse applications. To address these gaps, this paper provides a comprehensive review of the PHM field, followed by an introduction of a systematic PHM design methodology, 5S methodology, for converting data to prognostics information. This methodology includes procedures for identifying critical components, as well as tools for selecting the most appropriate algorithms for specific applications. Visualization tools are presented for displaying prognostics information in an appropriate fashion for quick and accurate decision making. Industrial case studies are included in this paper to show how this methodology can help in the design of an effective PHM system.

  7. Methodology for a stormwater sensitive urban watershed design

    NASA Astrophysics Data System (ADS)

    Romnée, Ambroise; Evrard, Arnaud; Trachte, Sophie

    2015-11-01

    In urban stormwater management, decentralized systems are nowadays worldwide experimented, including stormwater best management practices. However, a watershed-scale approach, relevant for urban hydrology, is almost always neglected when designing a stormwater management plan with best management practices. As a consequence, urban designers fail to convince public authorities of the actual hydrologic effectiveness of such an approach to urban watershed stormwater management. In this paper, we develop a design oriented methodology for studying the morphology of an urban watershed in terms of sustainable stormwater management. The methodology is a five-step method, firstly based on the cartographic analysis of many stormwater relevant indicators regarding the landscape, the urban fabric and the governance. The second step focuses on the identification of many territorial stakes and their corresponding strategies of a decentralized stormwater management. Based on the indicators, the stakes and the strategies, the third step defines many spatial typologies regarding the roadway system and the urban fabric system. The fourth step determines many stormwater management scenarios to be applied to both spatial typologies systems. The fifth step is the design of decentralized stormwater management projects integrating BMPs into each spatial typology. The methodology aims to advise urban designers and engineering offices in the right location and selection of BMPs without given them a hypothetical unique solution. Since every location and every watershed is different due to local guidelines and stakeholders, this paper provide a methodology for a stormwater sensitive urban watershed design that could be reproduced everywhere. As an example, the methodology is applied as a case study to an urban watershed in Belgium, confirming that the method is applicable to any urban watershed. This paper should be helpful for engineering and design offices in urban hydrology to define a

  8. Implementation of Probabilistic Design Methodology at Tennessee State University

    NASA Technical Reports Server (NTRS)

    Onwubiko, Chinyere

    1996-01-01

    Engineering Design is one of the most important areas in engineering education. Deterministic Design Methodology (DDM) is the only design method that is taught in most engineering schools. This method does not give a direct account of uncertainties in design parameters. Hence, it is impossible to quantify the uncertainties in the response and the actual safety margin remains unknown. The desire for a design methodology tha can identify the primitive (random) variables that affect the structural behavior has led to a growing interest on Probabilistic Design Methodology (PDM). This method is gaining more recognition in industries than in educational institutions. Some of the reasons for the limited use of the PDM at the moment are that many are unaware of its potentials, and most of the software developed for PDM are very recent. The central goal of the PDM project at Tennessee State University is to introduce engineering students to the method. The students participating in the project learn about PDM and the computer codes that are available to the design engineer. The software being used of this project is NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) developed under NASA probabilistic structural analysis program. NESSUS has three different modules which make it a very comprehensive computer code for PDM. A research in technology transfer through course offering in PDM is in effect a Tennessee State University. The aim is to familiarize students with the problem of uncertainties in engineering design. Included in the paper are some projects on PDM carried out by some students and faculty. The areas this method is being applied at the moment include, Design of Gears (spur and worm); Design of Shafts; Design of Statistically Indeterminate Frame Structures; Design of Helical Springs; and Design of Shock Absorbers. Some of the current results of these projects are presented.

  9. Developing an evidence-based methodological framework to systematically compare HTA coverage decisions: A mixed methods study.

    PubMed

    Nicod, Elena; Kanavos, Panos

    2016-01-01

    Health Technology Assessment (HTA) often results in different coverage recommendations across countries for a same medicine despite similar methodological approaches. This paper develops and pilots a methodological framework that systematically identifies the reasons for these differences using an exploratory sequential mixed methods research design. The study countries were England, Scotland, Sweden and France. The methodological framework was built around three stages of the HTA process: (a) evidence, (b) its interpretation, and (c) its influence on the final recommendation; and was applied to two orphan medicinal products. The criteria accounted for at each stage were qualitatively analyzed through thematic analysis. Piloting the framework for two medicines, eight trials, 43 clinical endpoints and seven economic models were coded 155 times. Eighteen different uncertainties about this evidence were coded 28 times, 56% of which pertained to evidence commonly appraised and 44% to evidence considered by only some agencies. The poor agreement in interpreting this evidence (κ=0.183) was partly explained by stakeholder input (ns=48 times), or by agency-specific risk (nu=28 uncertainties) and value preferences (noc=62 "other considerations"), derived through correspondence analysis. Accounting for variability at each stage of the process can be achieved by codifying its existence and quantifying its impact through the application of this framework. The transferability of this framework to other disease areas, medicines and countries is ensured by its iterative and flexible nature, and detailed description. PMID:26723201

  10. Single-Case Experimental Designs: A Systematic Review of Published Research and Current Standards

    PubMed Central

    Smith, Justin D.

    2013-01-01

    This article systematically reviews the research design and methodological characteristics of single-case experimental design (SCED) research published in peer-reviewed journals between 2000 and 2010. SCEDs provide researchers with a flexible and viable alternative to group designs with large sample sizes. However, methodological challenges have precluded widespread implementation and acceptance of the SCED as a viable complementary methodology to the predominant group design. This article includes a description of the research design, measurement, and analysis domains distinctive to the SCED; a discussion of the results within the framework of contemporary standards and guidelines in the field; and a presentation of updated benchmarks for key characteristics (e.g., baseline sampling, method of analysis), and overall, it provides researchers and reviewers with a resource for conducting and evaluating SCED research. The results of the systematic review of 409 studies suggest that recently published SCED research is largely in accordance with contemporary criteria for experimental quality. Analytic method emerged as an area of discord. Comparison of the findings of this review with historical estimates of the use of statistical analysis indicates an upward trend, but visual analysis remains the most common analytic method and also garners the most support amongst those entities providing SCED standards. Although consensus exists along key dimensions of single-case research design and researchers appear to be practicing within these parameters, there remains a need for further evaluation of assessment and sampling techniques and data analytic methods. PMID:22845874

  11. The methodological quality of systematic reviews comparing intravitreal bevacizumab and alternates for neovascular age related macular degeneration: A systematic review of reviews

    PubMed Central

    George, Pradeep Paul; DeCastro Molina, Joseph Antonio; Heng, Bee Hoon

    2014-01-01

    Objective: To systematically collate and evaluate the evidence from recent SRs of bevacizumab for neo-vascular age related macular degeneration. Materials and Methods: Literature searches were carried out in Medline, Embase, Cochrane databases for all systematic reviews (SRs) on the effectiveness of bevacizumab for neo-vascular age related macular degeneration, published between 2000 and 2013. Titles and abstracts were assessed against the inclusion/exclusion criteria using Joanna Briggs Institute (JBI) study eligibility form. Data was extracted using the JBI data extraction form. The quality of the SRs was assessed using JBI critical appraisal checklist for SRs. Decisions on study eligibility and quality were made by two reviewers; any disagreements were resolved by discussion. Results: Nine relevant reviews were identified from 30 citations, of which 5 reviews fulfilled the review's inclusion criteria. All 5 reviews showed bevacizumab to be effective for neovascular AMD in the short-term when used alone or in combination with PDT or Pegaptanib. The average quality score of the reviews was 7; 95% confidence interval 6.2 to 7.8 (maximum possible quality score is 10). The selection and publication bias were not addressed in all included reviews. Three-fifth of the reviews had a quality score of 7 or lower, these reviews had some methodological limitations, search strategies were only identified in 2 (40%) reviews, independent study selection and quality assessment of included studies (4 (80%)) were infrequently performed. Conclusion: Overall, the reviews on the effectiveness of intravitreal/systemic bevacizumab for neovascularage-related macular generation (AMD) received good JBI quality scores (mean score = 7.0 points), with a few exceptions. The study also highlights the suboptimal reporting of SRs on this topic. Reviews with poor methodology may limit the validity of the reported results; hence efforts should be made to improve the design, reporting and

  12. Extensibility of a linear rapid robust design methodology

    NASA Astrophysics Data System (ADS)

    Steinfeldt, Bradley A.; Braun, Robert D.

    2016-05-01

    The extensibility of a linear rapid robust design methodology is examined. This analysis is approached from a computational cost and accuracy perspective. The sensitivity of the solution's computational cost is examined by analysing effects such as the number of design variables, nonlinearity of the CAs, and nonlinearity of the response in addition to several potential complexity metrics. Relative to traditional robust design methods, the linear rapid robust design methodology scaled better with the size of the problem and had performance that exceeded the traditional techniques examined. The accuracy of applying a method with linear fundamentals to nonlinear problems was examined. It is observed that if the magnitude of nonlinearity is less than 1000 times that of the nominal linear response, the error associated with applying successive linearization will result in ? errors in the response less than 10% compared to the full nonlinear error.

  13. Viability, Advantages and Design Methodologies of M-Learning Delivery

    ERIC Educational Resources Information Center

    Zabel, Todd W.

    2010-01-01

    The purpose of this study was to examine the viability and principle design methodologies of Mobile Learning models in developing regions. Demographic and market studies were utilized to determine the viability of M-Learning delivery as well as best uses for such technologies and methods given socioeconomic and political conditions within the…

  14. A computer simulator for development of engineering system design methodologies

    NASA Technical Reports Server (NTRS)

    Padula, S. L.; Sobieszczanski-Sobieski, J.

    1987-01-01

    A computer program designed to simulate and improve engineering system design methodology is described. The simulator mimics the qualitative behavior and data couplings occurring among the subsystems of a complex engineering system. It eliminates the engineering analyses in the subsystems by replacing them with judiciously chosen analytical functions. With the cost of analysis eliminated, the simulator is used for experimentation with a large variety of candidate algorithms for multilevel design optimization to choose the best ones for the actual application. Thus, the simulator serves as a development tool for multilevel design optimization strategy. The simulator concept, implementation, and status are described and illustrated with examples.

  15. Tornado missile simulation and design methodology. Volume 1: simulation methodology, design applications, and TORMIS computer code. Final report

    SciTech Connect

    Twisdale, L.A.; Dunn, W.L.

    1981-08-01

    A probabilistic methodology has been developed to predict the probabilities of tornado-propelled missiles impacting and damaging nuclear power plant structures. Mathematical models of each event in the tornado missile hazard have been developed and sequenced to form an integrated, time-history simulation methodology. The models are data based where feasible. The data include documented records of tornado occurrence, field observations of missile transport, results of wind tunnel experiments, and missile impact tests. Probabilistic Monte Carlo techniques are used to estimate the risk probabilities. The methodology has been encoded in the TORMIS computer code to facilitate numerical analysis and plant-specific tornado missile probability assessments. Sensitivity analyses have been performed on both the individual models and the integrated methodology, and risk has been assessed for a hypothetical nuclear power plant design case study.

  16. Are we talking the same paradigm? Considering methodological choices in health education systematic review

    PubMed Central

    Gordon, Morris

    2016-01-01

    Abstract For the past two decades, there have been calls for medical education to become more evidence-based. Whilst previous works have described how to use such methods, there are no works discussing when or why to select different methods from either a conceptual or pragmatic perspective. This question is not to suggest the superiority of such methods, but that having a clear rationale to underpin such choices is key and should be communicated to the reader of such works. Our goal within this manuscript is to consider the philosophical alignment of these different review and synthesis modalities and how this impacts on their suitability to answer different systematic review questions within health education. The key characteristic of a systematic review that should impact the synthesis choice is discussed in detail. By clearly defining this and the related outcome expected from the review and for educators who will receive this outcome, the alignment will become apparent. This will then allow deployment of an appropriate methodology that is fit for purpose and will indeed justify the significant work needed to complete a systematic. Key items discussed are the positivist synthesis methods meta-analysis and content analysis to address questions in the form of ‘whether and what’ education is effective. These can be juxtaposed with the constructivist aligned thematic analysis and meta-ethnography to address questions in the form of ‘why’. The concept of the realist review is also considered. It is proposed that authors of such work should describe their research alignment and the link between question, alignment and evidence synthesis method selected. The process of exploring the range of modalities and their alignment highlights gaps in the researcher’s arsenal. Future works are needed to explore the impact of such changes in writing from authors of medical education systematic review. PMID:27007488

  17. Are we talking the same paradigm? Considering methodological choices in health education systematic review.

    PubMed

    Gordon, Morris

    2016-07-01

    For the past two decades, there have been calls for medical education to become more evidence-based. Whilst previous works have described how to use such methods, there are no works discussing when or why to select different methods from either a conceptual or pragmatic perspective. This question is not to suggest the superiority of such methods, but that having a clear rationale to underpin such choices is key and should be communicated to the reader of such works. Our goal within this manuscript is to consider the philosophical alignment of these different review and synthesis modalities and how this impacts on their suitability to answer different systematic review questions within health education. The key characteristic of a systematic review that should impact the synthesis choice is discussed in detail. By clearly defining this and the related outcome expected from the review and for educators who will receive this outcome, the alignment will become apparent. This will then allow deployment of an appropriate methodology that is fit for purpose and will indeed justify the significant work needed to complete a systematic. Key items discussed are the positivist synthesis methods meta-analysis and content analysis to address questions in the form of 'whether and what' education is effective. These can be juxtaposed with the constructivist aligned thematic analysis and meta-ethnography to address questions in the form of 'why'. The concept of the realist review is also considered. It is proposed that authors of such work should describe their research alignment and the link between question, alignment and evidence synthesis method selected. The process of exploring the range of modalities and their alignment highlights gaps in the researcher's arsenal. Future works are needed to explore the impact of such changes in writing from authors of medical education systematic review. PMID:27007488

  18. FOREWORD: Computational methodologies for designing materials Computational methodologies for designing materials

    NASA Astrophysics Data System (ADS)

    Rahman, Talat S.

    2009-02-01

    It would be fair to say that in the past few decades, theory and computer modeling have played a major role in elucidating the microscopic factors that dictate the properties of functional novel materials. Together with advances in experimental techniques, theoretical methods are becoming increasingly capable of predicting properties of materials at different length scales, thereby bringing in sight the long-sought goal of designing material properties according to need. Advances in computer technology and their availability at a reasonable cost around the world have made tit all the more urgent to disseminate what is now known about these modern computational techniques. In this special issue on computational methodologies for materials by design we have tried to solicit articles from authors whose works collectively represent the microcosm of developments in the area. This turned out to be a difficult task for a variety of reasons, not the least of which is space limitation in this special issue. Nevertheless, we gathered twenty articles that represent some of the important directions in which theory and modeling are proceeding in the general effort to capture the ability to produce materials by design. The majority of papers presented here focus on technique developments that are expected to uncover further the fundamental processes responsible for material properties, and for their growth modes and morphological evolutions. As for material properties, some of the articles here address the challenges that continue to emerge from attempts at accurate descriptions of magnetic properties, of electronically excited states, and of sparse matter, all of which demand new looks at density functional theory (DFT). I should hasten to add that much of the success in accurate computational modeling of materials emanates from the remarkable predictive power of DFT, without which we would not be able to place the subject on firm theoretical grounds. As we know and will also

  19. A robust optimization methodology for preliminary aircraft design

    NASA Astrophysics Data System (ADS)

    Prigent, S.; Maréchal, P.; Rondepierre, A.; Druot, T.; Belleville, M.

    2016-05-01

    This article focuses on a robust optimization of an aircraft preliminary design under operational constraints. According to engineers' know-how, the aircraft preliminary design problem can be modelled as an uncertain optimization problem whose objective (the cost or the fuel consumption) is almost affine, and whose constraints are convex. It is shown that this uncertain optimization problem can be approximated in a conservative manner by an uncertain linear optimization program, which enables the use of the techniques of robust linear programming of Ben-Tal, El Ghaoui, and Nemirovski [Robust Optimization, Princeton University Press, 2009]. This methodology is then applied to two real cases of aircraft design and numerical results are presented.

  20. Methodological developments in searching for studies for systematic reviews: past, present and future?

    PubMed

    Lefebvre, Carol; Glanville, Julie; Wieland, L Susan; Coles, Bernadette; Weightman, Alison L

    2013-01-01

    The Cochrane Collaboration was established in 1993, following the opening of the UK Cochrane Centre in 1992, at a time when searching for studies for inclusion in systematic reviews was not well-developed. Review authors largely conducted their own searches or depended on medical librarians, who often possessed limited awareness and experience of systematic reviews. Guidance on the conduct and reporting of searches was limited. When work began to identify reports of randomized controlled trials (RCTs) for inclusion in Cochrane Reviews in 1992, there were only approximately 20,000 reports indexed as RCTs in MEDLINE and none indexed as RCTs in Embase. No search filters had been developed with the aim of identifying all RCTs in MEDLINE or other major databases. This presented The Cochrane Collaboration with a considerable challenge in identifying relevant studies.Over time, the number of studies indexed as RCTs in the major databases has grown considerably and the Cochrane Central Register of Controlled Trials (CENTRAL) has become the best single source of published controlled trials, with approximately 700,000 records, including records identified by the Collaboration from Embase and MEDLINE. Search filters for various study types, including systematic reviews and the Cochrane Highly Sensitive Search Strategies for RCTs, have been developed. There have been considerable advances in the evidence base for methodological aspects of information retrieval. The Cochrane Handbook for Systematic Reviews of Interventions now provides detailed guidance on the conduct and reporting of searches. Initiatives across The Cochrane Collaboration to improve the quality inter alia of information retrieval include: the recently introduced Methodological Expectations for Cochrane Intervention Reviews (MECIR) programme, which stipulates 'mandatory' and 'highly desirable' standards for various aspects of review conduct and reporting including searching, the development of Standard Training

  1. Methodological developments in searching for studies for systematic reviews: past, present and future?

    PubMed Central

    2013-01-01

    The Cochrane Collaboration was established in 1993, following the opening of the UK Cochrane Centre in 1992, at a time when searching for studies for inclusion in systematic reviews was not well-developed. Review authors largely conducted their own searches or depended on medical librarians, who often possessed limited awareness and experience of systematic reviews. Guidance on the conduct and reporting of searches was limited. When work began to identify reports of randomized controlled trials (RCTs) for inclusion in Cochrane Reviews in 1992, there were only approximately 20,000 reports indexed as RCTs in MEDLINE and none indexed as RCTs in Embase. No search filters had been developed with the aim of identifying all RCTs in MEDLINE or other major databases. This presented The Cochrane Collaboration with a considerable challenge in identifying relevant studies. Over time, the number of studies indexed as RCTs in the major databases has grown considerably and the Cochrane Central Register of Controlled Trials (CENTRAL) has become the best single source of published controlled trials, with approximately 700,000 records, including records identified by the Collaboration from Embase and MEDLINE. Search filters for various study types, including systematic reviews and the Cochrane Highly Sensitive Search Strategies for RCTs, have been developed. There have been considerable advances in the evidence base for methodological aspects of information retrieval. The Cochrane Handbook for Systematic Reviews of Interventions now provides detailed guidance on the conduct and reporting of searches. Initiatives across The Cochrane Collaboration to improve the quality inter alia of information retrieval include: the recently introduced Methodological Expectations for Cochrane Intervention Reviews (MECIR) programme, which stipulates 'mandatory’ and 'highly desirable’ standards for various aspects of review conduct and reporting including searching, the development of Standard

  2. An automated methodology development. [software design for combat simulation

    NASA Technical Reports Server (NTRS)

    Hawley, L. R.

    1985-01-01

    The design methodology employed in testing the applicability of Ada in large-scale combat simulations is described. Ada was considered as a substitute for FORTRAN to lower life cycle costs and ease the program development efforts. An object-oriented approach was taken, which featured definitions of military targets, the capability of manipulating their condition in real-time, and one-to-one correlation between the object states and real world states. The simulation design process was automated by the problem statement language (PSL)/problem statement analyzer (PSA). The PSL/PSA system accessed the problem data base directly to enhance the code efficiency by, e.g., eliminating non-used subroutines, and provided for automated report generation, besides allowing for functional and interface descriptions. The ways in which the methodology satisfied the responsiveness, reliability, transportability, modifiability, timeliness and efficiency goals are discussed.

  3. Development of a Design Methodology for Reconfigurable Flight Control Systems

    NASA Technical Reports Server (NTRS)

    Hess, Ronald A.; McLean, C.

    2000-01-01

    A methodology is presented for the design of flight control systems that exhibit stability and performance-robustness in the presence of actuator failures. The design is based upon two elements. The first element consists of a control law that will ensure at least stability in the presence of a class of actuator failures. This law is created by inner-loop, reduced-order, linear dynamic inversion, and outer-loop compensation based upon Quantitative Feedback Theory. The second element consists of adaptive compensators obtained from simple and approximate time-domain identification of the dynamics of the 'effective vehicle' with failed actuator(s). An example involving the lateral-directional control of a fighter aircraft is employed both to introduce the proposed methodology and to demonstrate its effectiveness and limitations.

  4. A SYSTEMATIC PROCEDURE FOR DESIGNING PROCESSES WITH MULTIPLE ENVIRONMENTAL OBJECTIVES

    EPA Science Inventory

    Evaluation and analysis of multiple objectives are very important in designing environmentally benign processes. They require a systematic procedure for solving multi-objective decision-making problems due to the complex nature of the problems and the need for complex assessment....

  5. Designs and Methods in School Improvement Research: A Systematic Review

    ERIC Educational Resources Information Center

    Feldhoff, Tobias; Radisch, Falk; Bischof, Linda Marie

    2016-01-01

    Purpose: The purpose of this paper is to focus on challenges faced by longitudinal quantitative analyses of school improvement processes and offers a systematic literature review of current papers that use longitudinal analyses. In this context, the authors assessed designs and methods that are used to analyze the relation between school…

  6. Methodology for system description using the software design & documentation language

    NASA Technical Reports Server (NTRS)

    Kleine, H.

    1985-01-01

    The Software Design and Documentation Language (SDDL) can be loosely characterized as a text processor with built-in knowledge of, and methods for handling the concepts of structure and abstraction which are essential for developing software and other information intensive systems. Several aspects of system descriptions to which SDDL has been applied are presented and specific SDDL methodologies developed for these applications are discussed.

  7. A systematic computational methodology applied to a three-dimensional film-cooling flowfield

    SciTech Connect

    Walters, D.K.; Leylek, J.H.

    1997-10-01

    Numerical results are presented for a three-dimensional discrete-jet in crossflow problem typical of a realistic film-cooling application in gas turbines. Key aspects of the study include: (1) application of a systematic computational methodology that stresses accurate computational model of the physical problem, including simultaneous, fully elliptic solution of the crossflow, film-hole, and plenum regions; high-quality three-dimensional unstructured grid generation techniques, which have yet to be documented for this class of problems; the use of a high-order discretization scheme to reduce numerical errors significantly; and effective turbulence modeling; (2) a three-way comparison of results to both code validation quality experimental data and a previously documented structured grid simulation; and (3) identification of sources of discrepancy between predicted and measured results, as well as recommendations to alleviate these discrepancies. Solutions were obtained with a multiblock, unstructured/adaptive grid, fully explicit, time-marching, Reynolds-averaged Navier-Stokes code with multigrid, local time stepping, and residual smoothing type acceleration techniques. The computational methodology was applied to the validation test case of a row of discrete jets on a flat plate with a streamwise injection angle of 35 deg, and two film-hole length-to-diameter ratios of 3.5 and 1.75. The density ratio for all cases was 2.0, blowing ratio was varied from 0.5 to 2.0, and free-stream turbulence intensity was 2%. The results demonstrate that the prescribed computational methodology yields consistently more accurate solutions for this class of problems than previous attempts published in the open literature. Sources of disagreement between measured and computed results have been identified, and recommendations made for future prediction of film-cooling problems.

  8. Thin Film Heat Flux Sensors: Design and Methodology

    NASA Technical Reports Server (NTRS)

    Fralick, Gustave C.; Wrbanek, John D.

    2013-01-01

    Thin Film Heat Flux Sensors: Design and Methodology: (1) Heat flux is one of a number of parameters, together with pressure, temperature, flow, etc. of interest to engine designers and fluid dynamists, (2) The measurement of heat flux is of interest in directly determining the cooling requirements of hot section blades and vanes, and (3)In addition, if the surface and gas temperatures are known, the measurement of heat flux provides a value for the convective heat transfer coefficient that can be compared with the value provided by CFD codes.

  9. When Playing Meets Learning: Methodological Framework for Designing Educational Games

    NASA Astrophysics Data System (ADS)

    Linek, Stephanie B.; Schwarz, Daniel; Bopp, Matthias; Albert, Dietrich

    Game-based learning builds upon the idea of using the motivational potential of video games in the educational context. Thus, the design of educational games has to address optimizing enjoyment as well as optimizing learning. Within the EC-project ELEKTRA a methodological framework for the conceptual design of educational games was developed. Thereby state-of-the-art psycho-pedagogical approaches were combined with insights of media-psychology as well as with best-practice game design. This science-based interdisciplinary approach was enriched by enclosed empirical research to answer open questions on educational game-design. Additionally, several evaluation-cycles were implemented to achieve further improvements. The psycho-pedagogical core of the methodology can be summarized by the ELEKTRA's 4Ms: Macroadaptivity, Microadaptivity, Metacognition, and Motivation. The conceptual framework is structured in eight phases which have several interconnections and feedback-cycles that enable a close interdisciplinary collaboration between game design, pedagogy, cognitive science and media psychology.

  10. Implementation of probabilistic design methodology at Tennessee State University

    NASA Technical Reports Server (NTRS)

    Onwubiko, Chinyere

    1995-01-01

    The fact that Deterministic Design Method no longer satisfies most design needs calls for methods that will cope with the high trend in technology. The advance in computer technology has reduced the rigors that normally accompany many design analysis methods that account for uncertainties in design parameters. Probabilistic Design Methodology (PDM) is beginning to make impact in engineering design. This method is gaining more recognition in industries than in educational institutions. Some of the reasons for the limited use of the PDM at the moment are that many are unaware of its potentials, and most of the software developed for PDM are very recent. The central goal of the PDM project at Tennessee State University is to introduce engineering students to this method. The students participating in the project learn about PDM and the computer codes that are available to the design engineer. The software being used for this project is NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) developed under NASA probabilistic structural analysis program. NESSUS has three different modules which make it a very comprehensive computer code for PDM. Since this method is new to the students, its introduction into the engineering curriculum is to be in stages. These range from the introduction of PDM and its software to the applications. While this program is being developed for its eventual inclusion into the engineering curriculum, some graduate and undergraduate students are already carrying out some projects using this method. As the students are increasing their understanding on PDM, they are at the same time applying it to some common design problems. The areas this method is being applied at the moment include, Design of Gears (spur and worm); Design of Brakes; Design of Heat Exchangers Design of Helical Springs; and Design of Shock Absorbers. Some of the current results of these projects are presented.

  11. Gaining system design knowledge by systematic design space exploration with graph based design languages

    NASA Astrophysics Data System (ADS)

    Schmidt, Jens; Rudolph, Stephan

    2014-10-01

    The conceptual design phase in the design of complex systems such as satellite propulsion systems heavily relies on an exploration of the feasible design space. This exploration requires both: topological changes in the potential system architecture and consistent parametrical changes in the dimensioning of the existing system components. Since advanced engineering design techniques nowadays advocate a model-based systems engineering (MBSE) approach, graph-based design languages which embed a superset of MBSE-features are consequently used in this work to systematically explore the feasible design space. Design languages allow the design knowledge to be represented, modeled and executed using model-based transformations and combine this among other features with constraint processing techniques. The execution of the design language shown for the satellite propulsion systems in this work yields topologically varied designs (i.e. the selection of a monergol, a diergol or a coldgas system) with consistent parameters. Based on an a posteriori performance analysis of the automatically generated system designs, novel system knowledge (most notably in form of so-called "topology change points") can be gained and extracted from the original point cloud of numerical results.

  12. Evaluation of methodology and quality characteristics of systematic reviews in orthodontics.

    PubMed

    Papageorgiou, S N; Papadopoulos, M A; Athanasiou, A E

    2011-08-01

    Systematic reviews (SRs) are published with an increasing rate in many fields of biomedical literature, including orthodontics. Although SRs should consolidate the evidence-based characteristics of contemporary orthodontic practice, doubts on the validity of their conclusions have been frequently expressed. The aim of this study was to evaluate the methodology and quality characteristics of orthodontic SRs as well as to assess their quality of reporting during the last years. Electronic databases were searched for SRs (without any meta-analytical data synthesis) in the field of orthodontics, indexed up to the start of 2010. The Assessment of Multiple Systematic Reviews (AMSTAR) tool was used for quality assessment of the included articles. Data were analyzed with Student's t-test, one-way ANOVA, and linear regression. Risk ratios (RR) with 95% confidence intervals were calculated to represent changes during the years in reporting of key items associated with quality. A total of 110 SRs were included in this evaluation. About half of the SRs (46.4%) were published in orthodontic journals, while few (5.5%) were updates of previously published reviews. Using the AMSTAR tool, thirty (27.3%) of the SRs were found to be of low quality, 63 (57.3%) of medium quality, and 17 (15.5%) of high quality. No significant trend for quality improvement was observed during the last years. The overall quality of orthodontic SRs may be considered as medium. Although the number of orthodontic SRs has increased over the last decade, their quality characteristics can be characterized as moderate. PMID:21771267

  13. The uniqueness of the human dentition as forensic evidence: a systematic review on the technological methodology.

    PubMed

    Franco, Ademir; Willems, Guy; Souza, Paulo Henrique Couto; Bekkering, Geertruida E; Thevissen, Patrick

    2015-11-01

    The uniqueness of human dentition is routinely approached as identification evidence in forensic odontology. Specifically in bitemark and human identification cases, positive identifications are obtained under the hypothesis that two individuals do not have the same dental features. The present study compiles methodological information from articles on the uniqueness of human dentition to support investigations into the mentioned hypothesis. In April 2014, three electronic library databases (SciELO®, MEDLINE®/PubMed®, and LILACS®) were systematically searched. In parallel, reference lists of relevant studies were also screened. From the obtained articles (n = 1235), 13 full-text articles were considered eligible. They were examined according to the studied parameters: the sample size, the number of examined teeth, the registration technique for data collection, the methods for data analysis, and the study outcomes. Six combinations of studied data were detected: (1) dental shape, size, angulation, and position (n = 1); (2) dental shape, size, and angulation (n = 4); (3) dental shape and size (n = 5); (4) dental angulation and position (n = 2); (5) dental shape and angulation (n = 1); and (6) dental shape (n = 1). The sample size ranged between 10 and 1099 human dentitions. Ten articles examined the six anterior teeth, while three articles examined more teeth. Four articles exclusively addressed three-dimensional (3D) data registration, while six articles used two-dimensional (2D) imaging. In three articles, both imaging registrations were combined. Most articles (n = 9) explored the data using landmark placement. The other articles (n = 4) comprised digital comparison of superimposed dental contours. Although there were large methodological variations within the investigated articles, the uniqueness of human dentition remains unproved. PMID:25398633

  14. Aircraft conceptual design - an adaptable parametric sizing methodology

    NASA Astrophysics Data System (ADS)

    Coleman, Gary John, Jr.

    Aerospace is a maturing industry with successful and refined baselines which work well for traditional baseline missions, markets and technologies. However, when new markets (space tourism) or new constrains (environmental) or new technologies (composite, natural laminar flow) emerge, the conventional solution is not necessarily best for the new situation. Which begs the question "how does a design team quickly screen and compare novel solutions to conventional solutions for new aerospace challenges?" The answer is rapid and flexible conceptual design Parametric Sizing. In the product design life-cycle, parametric sizing is the first step in screening the total vehicle in terms of mission, configuration and technology to quickly assess first order design and mission sensitivities. During this phase, various missions and technologies are assessed. During this phase, the designer is identifying design solutions of concepts and configurations to meet combinations of mission and technology. This research undertaking contributes the state-of-the-art in aircraft parametric sizing through (1) development of a dedicated conceptual design process and disciplinary methods library, (2) development of a novel and robust parametric sizing process based on 'best-practice' approaches found in the process and disciplinary methods library, and (3) application of the parametric sizing process to a variety of design missions (transonic, supersonic and hypersonic transports), different configurations (tail-aft, blended wing body, strut-braced wing, hypersonic blended bodies, etc.), and different technologies (composite, natural laminar flow, thrust vectored control, etc.), in order to demonstrate the robustness of the methodology and unearth first-order design sensitivities to current and future aerospace design problems. This research undertaking demonstrates the importance of this early design step in selecting the correct combination of mission, technologies and configuration to

  15. Development and implementation of rotorcraft preliminary design methodology using multidisciplinary design optimization

    NASA Astrophysics Data System (ADS)

    Khalid, Adeel Syed

    Rotorcraft's evolution has lagged behind that of fixed-wing aircraft. One of the reasons for this gap is the absence of a formal methodology to accomplish a complete conceptual and preliminary design. Traditional rotorcraft methodologies are not only time consuming and expensive but also yield sub-optimal designs. Rotorcraft design is an excellent example of a multidisciplinary complex environment where several interdependent disciplines are involved. A formal framework is developed and implemented in this research for preliminary rotorcraft design using IPPD methodology. The design methodology consists of the product and process development cycles. In the product development loop, all the technical aspects of design are considered including the vehicle engineering, dynamic analysis, stability and control, aerodynamic performance, propulsion, transmission design, weight and balance, noise analysis and economic analysis. The design loop starts with a detailed analysis of requirements. A baseline is selected and upgrade targets are identified depending on the mission requirements. An Overall Evaluation Criterion (OEC) is developed that is used to measure the goodness of the design or to compare the design with competitors. The requirements analysis and baseline upgrade targets lead to the initial sizing and performance estimation of the new design. The digital information is then passed to disciplinary experts. This is where the detailed disciplinary analyses are performed. Information is transferred from one discipline to another as the design loop is iterated. To coordinate all the disciplines in the product development cycle, Multidisciplinary Design Optimization (MDO) techniques e.g. All At Once (AAO) and Collaborative Optimization (CO) are suggested. The methodology is implemented on a Light Turbine Training Helicopter (LTTH) design. Detailed disciplinary analyses are integrated through a common platform for efficient and centralized transfer of design

  16. Development of the Spanish version of the Systematized Nomenclature of Medicine: methodology and main issues.

    PubMed Central

    Reynoso, G. A.; March, A. D.; Berra, C. M.; Strobietto, R. P.; Barani, M.; Iubatti, M.; Chiaradio, M. P.; Serebrisky, D.; Kahn, A.; Vaccarezza, O. A.; Leguiza, J. L.; Ceitlin, M.; Luna, D. A.; Bernaldo de Quirós, F. G.; Otegui, M. I.; Puga, M. C.; Vallejos, M.

    2000-01-01

    This presentation features linguistic and terminology management issues related to the development of the Spanish version of the Systematized Nomenclature of Medicine (SNOMED). It aims at describing the aspects of translating and the difficulties encountered in delivering a natural and consistent medical nomenclature. Bunge's three-layered model is referenced to analyze the sequence of symbolic concept representations. It further explains how a communicative translation based on a concept-to-concept approach was used to achieve the highest level of flawlessness and naturalness for the Spanish rendition of SNOMED. Translation procedures and techniques are described and exemplified. Both the computer-aided and human translation methods are portrayed. The scientific and translation team tasks are detailed, with focus on Newmark's four-level principle for the translation process, extended with a fifth further level relevant to the ontology to control the consistency of the typology of concepts. Finally the convenience for a common methodology to develop non-English versions of SNOMED is suggested. PMID:11079973

  17. Experimental facility and methodology for systematic studies of cold startability in direct injection Diesel engines

    NASA Astrophysics Data System (ADS)

    Pastor, J. V.; García-Oliver, J. M.; Pastor, J. M.; Ramírez-Hernández, J. G.

    2009-09-01

    Cold start at low temperatures in current direct injection (DI) Diesel engines is a problem which has not yet been properly solved and it becomes particularly critical with the current trend to reduce the engine compression ratio. Although it is clear that there are some key factors whose control leads to a proper cold start process, their individual relevance and relationships are not clearly understood. Thus, efforts on optimization of the cold start process are mainly based on a trial-and-error procedure in climatic chambers at low ambient temperature, with serious limitations in terms of measurement reliability during such a transient process, low repeatability and experimental cost. This paper presents a novel approach for an experimental facility capable of simulating real engine cold start, at room temperature and under well-controlled low speed and low temperature conditions. It is based on an optical single cylinder engine adapted to reproduce in-cylinder conditions representative of those of a real engine during start at cold ambient temperatures (of the order of -20 °C). Such conditions must be realistic, controlled and repeatable in order to perform systematic studies in the borderline between ignition success and misfiring. An analysis methodology, combining optical techniques and heat release analysis of individual cycles, has been applied.

  18. The Study of the Relationship between Probabilistic Design and Axiomatic Design Methodology. Volume 2

    NASA Technical Reports Server (NTRS)

    Onwubiko, Chin-Yere; Onyebueke, Landon

    1996-01-01

    The structural design, or the design of machine elements, has been traditionally based on deterministic design methodology. The deterministic method considers all design parameters to be known with certainty. This methodology is, therefore, inadequate to design complex structures that are subjected to a variety of complex, severe loading conditions. A nonlinear behavior that is dependent on stress, stress rate, temperature, number of load cycles, and time is observed on all components subjected to complex conditions. These complex conditions introduce uncertainties; hence, the actual factor of safety margin remains unknown. In the deterministic methodology, the contingency of failure is discounted; hence, there is a use of a high factor of safety. It may be most useful in situations where the design structures are simple. The probabilistic method is concerned with the probability of non-failure performance of structures or machine elements. It is much more useful in situations where the design is characterized by complex geometry, possibility of catastrophic failure, sensitive loads and material properties. Also included: Comparative Study of the use of AGMA Geometry Factors and Probabilistic Design Methodology in the Design of Compact Spur Gear Set.

  19. Developing Risk Prediction Models for Postoperative Pancreatic Fistula: a Systematic Review of Methodology and Reporting Quality.

    PubMed

    Wen, Zhang; Guo, Ya; Xu, Banghao; Xiao, Kaiyin; Peng, Tao; Peng, Minhao

    2016-04-01

    Postoperative pancreatic fistula is still a major complication after pancreatic surgery, despite improvements of surgical technique and perioperative management. We sought to systematically review and critically access the conduct and reporting of methods used to develop risk prediction models for predicting postoperative pancreatic fistula. We conducted a systematic search of PubMed and EMBASE databases to identify articles published before January 1, 2015, which described the development of models to predict the risk of postoperative pancreatic fistula. We extracted information of developing a prediction model including study design, sample size and number of events, definition of postoperative pancreatic fistula, risk predictor selection, missing data, model-building strategies, and model performance. Seven studies of developing seven risk prediction models were included. In three studies (42 %), the number of events per variable was less than 10. The number of candidate risk predictors ranged from 9 to 32. Five studies (71 %) reported using univariate screening, which was not recommended in building a multivariate model, to reduce the number of risk predictors. Six risk prediction models (86 %) were developed by categorizing all continuous risk predictors. The treatment and handling of missing data were not mentioned in all studies. We found use of inappropriate methods that could endanger the development of model, including univariate pre-screening of variables, categorization of continuous risk predictors, and model validation. The use of inappropriate methods affects the reliability and the accuracy of the probability estimates of predicting postoperative pancreatic fistula. PMID:27303124

  20. Empirical studies of clinical supervision in psychiatric nursing: A systematic literature review and methodological critique.

    PubMed

    Buus, Niels; Gonge, Henrik

    2009-08-01

    The objective of this paper was to systematically review and critically evaluate all English language research papers reporting empirical studies of clinical supervision in psychiatric nursing. The first part of the search strategy was a combination of brief and building block strategies in the PubMed, CINAHL, and PsycINFO databases. The second part was a citation pearl growing strategy with reviews of 179 reference lists. In total, the search strategy demonstrated a low level of precision and a high level of recall. Thirty four articles met the criteria of the review and were systematically evaluated using three checklists. The findings were summarized by using a new checklist with nine overall questions regarding the studies' design, methods, findings, and limitations. The studies were categorized as: (i) effect studies; (ii) survey studies; (iii) interview studies; and (iv) case studies. In general, the studies were relatively small scale; they used relatively new and basic methods for data collection and analysis, and rarely included sufficient strategies for identifying confounding factors or how the researchers' preconceptions influenced the analyses. Empirical research of clinical supervision in psychiatric nursing was characterized by a basic lack of agreement about which models and instruments to use. Challenges and recommendations for future research are discussed. Clinical supervision in psychiatric nursing was commonly perceived as a good thing, but there was limited empirical evidence supporting this claim. PMID:19594645

  1. Fast underdetermined BSS architecture design methodology for real time applications.

    PubMed

    Mopuri, Suresh; Reddy, P Sreenivasa; Acharyya, Amit; Naik, Ganesh R

    2015-01-01

    In this paper, we propose a high speed architecture design methodology for the Under-determined Blind Source Separation (UBSS) algorithm using our recently proposed high speed Discrete Hilbert Transform (DHT) targeting real time applications. In UBSS algorithm, unlike the typical BSS, the number of sensors are less than the number of the sources, which is of more interest in the real time applications. The DHT architecture has been implemented based on sub matrix multiplication method to compute M point DHT, which uses N point architecture recursively and where M is an integer multiples of N. The DHT architecture and state of the art architecture are coded in VHDL for 16 bit word length and ASIC implementation is carried out using UMC 90 - nm technology @V DD = 1V and @ 1MHZ clock frequency. The proposed architecture implementation and experimental comparison results show that the DHT design is two times faster than state of the art architecture. PMID:26737514

  2. Design Evolution and Methodology for Pumpkin Super-Pressure Balloons

    NASA Astrophysics Data System (ADS)

    Farley, Rodger

    The NASA Ultra Long Duration Balloon (ULDB) program has had many technical development issues discovered and solved along its road to success as a new vehicle. It has the promise of being a sub-satellite, a means to launch up to 2700 kg to 33.5 km altitude for 100 days from a comfortable mid-latitude launch point. Current high-lift long duration ballooning is accomplished out of Antarctica with zero-pressure balloons, which cannot cope with the rigors of diurnal cycles. The ULDB design is still evolving, the product of intense analytical effort, scaled testing, improved manufacturing, and engineering intuition. The past technical problems, in particular the s-cleft deformation, their solutions, future challenges, and the methodology of pumpkin balloon design will generally be described.

  3. The Usefulness of Systematic Reviews of Animal Experiments for the Design of Preclinical and Clinical Studies

    PubMed Central

    de Vries, Rob B. M.; Wever, Kimberley E.; Avey, Marc T.; Stephens, Martin L.; Sena, Emily S.; Leenaars, Marlies

    2014-01-01

    The question of how animal studies should be designed, conducted, and analyzed remains underexposed in societal debates on animal experimentation. This is not only a scientific but also a moral question. After all, if animal experiments are not appropriately designed, conducted, and analyzed, the results produced are unlikely to be reliable and the animals have in effect been wasted. In this article, we focus on one particular method to address this moral question, namely systematic reviews of previously performed animal experiments. We discuss how the design, conduct, and analysis of future (animal and human) experiments may be optimized through such systematic reviews. In particular, we illustrate how these reviews can help improve the methodological quality of animal experiments, make the choice of an animal model and the translation of animal data to the clinic more evidence-based, and implement the 3Rs. Moreover, we discuss which measures are being taken and which need to be taken in the future to ensure that systematic reviews will actually contribute to optimizing experimental design and thereby to meeting a necessary condition for making the use of animals in these experiments justified. PMID:25541545

  4. A design methodology for biologically inspired dry fibrillar adhesives

    NASA Astrophysics Data System (ADS)

    Aksak, Burak

    Realization of the unique aspects of gecko adhesion and incorporating these aspects into a comprehensive design methodology is essential to enable fabrication of application oriented gecko-inspired dry fibrillar adhesives. To address the need for such a design methodology, we propose a fibrillar adhesion model that evaluates the effect of fiber dimensions and material on adhesive performance of fiber arrays. A fibrillar adhesion model is developed to predict the adhesive characteristics of an array of fibrillar structures, and quantify the effect of fiber length, radius, spacing, and material. Photolithography techniques were utilized to fabricate elastomer microfiber arrays. Fibers that are fabricated from stiff SU-8 photoresist are used to fabricate a flexible negative mold that facilitates fabrication of fiber arrays from various elastomers with high yield. The tips of the cylindrical fibers are modified to mushroom-like tip shapes. Adhesive strengths in excess of 100 kPa is obtained with mushroom tipped elastomer microfibers. Vertically aligned carbon nanofibers (VACNFs) are utilized as enhanced friction materials by partially embedding inside soft polyurethanes. Friction coefficients up to 1 were repeatedly obtained from the resulting VACNF composite structures. A novel fabrication method is used to attach Poly(n-butyl acrylate) (PBA) molecular brush-like structures on the surface of polydimethylsiloxane (PDMS). These brushes are grown on unstructured PDMS and PDMS fibers with mushroom tips. Pull-off force is enhanced by up to 7 times with PBA brush grafted micro-fiber arrays over unstructured PDMS substrate. Adhesion model, initially developed for curved smooth surfaces, is extended to self-affine fractal surfaces to better reflect the adhesion performance of fiber arrays on natural surfaces. Developed adhesion model for fiber arrays is used in an optimization scheme which estimates optimal design parameters to obtain maximum adhesive strength on a given

  5. A variable-gain output feedback control design methodology

    NASA Technical Reports Server (NTRS)

    Halyo, Nesim; Moerder, Daniel D.; Broussard, John R.; Taylor, Deborah B.

    1989-01-01

    A digital control system design technique is developed in which the control system gain matrix varies with the plant operating point parameters. The design technique is obtained by formulating the problem as an optimal stochastic output feedback control law with variable gains. This approach provides a control theory framework within which the operating range of a control law can be significantly extended. Furthermore, the approach avoids the major shortcomings of the conventional gain-scheduling techniques. The optimal variable gain output feedback control problem is solved by embedding the Multi-Configuration Control (MCC) problem, previously solved at ICS. An algorithm to compute the optimal variable gain output feedback control gain matrices is developed. The algorithm is a modified version of the MCC algorithm improved so as to handle the large dimensionality which arises particularly in variable-gain control problems. The design methodology developed is applied to a reconfigurable aircraft control problem. A variable-gain output feedback control problem was formulated to design a flight control law for an AFTI F-16 aircraft which can automatically reconfigure its control strategy to accommodate failures in the horizontal tail control surface. Simulations of the closed-loop reconfigurable system show that the approach produces a control design which can accommodate such failures with relative ease. The technique can be applied to many other problems including sensor failure accommodation, mode switching control laws and super agility.

  6. Systematic search for major genes in schizophrenia: Methodological issues and results from chromosome 12

    SciTech Connect

    Dawson, E.; Powell, J.F.; Sham, P.

    1995-10-09

    We describe a method of systematically searching for major genes in disorders of unknown mode of inheritance, using linkage analysis. Our method is designed to minimize the probability of missing linkage due to inadequate exploration of data. We illustrate this method with the results of a search for a locus for schizophrenia on chromosome 12 using 22 highly polymorphic markers in 23 high density pedigrees. The markers span approximately 85-90% of the chromosome and are on average 9.35 cM apart. We have analysed the data using the most plausible current genetic models and allowing for the presence of genetic heterogeneity. None of the markers was supportive of linkage and the distribution of the heterogeneity statistics was in accordance with the null hypothesis. 53 refs., 2 figs., 4 tabs.

  7. Integrated design of the CSI evolutionary structure: A verification of the design methodology

    NASA Technical Reports Server (NTRS)

    Maghami, Peiman G.; Joshi, S. M.; Elliott, Kenny B.; Walz, J. E.

    1993-01-01

    One of the main objectives of the Controls-Structures Interaction (CSI) program is to develop and evaluate integrated controls-structures design methodology for flexible space structures. Thus far, integrated design methodologies for a class of flexible spacecraft, which require fine attitude pointing and vibration suppression with no payload articulation, have been extensively investigated. Various integrated design optimization approaches, such as single-objective optimization, and multi-objective optimization, have been implemented with an array of different objectives and constraints involving performance and cost measures such as total mass, actuator mass, steady-state pointing performance, transient performance, control power, and many more. These studies have been performed using an integrated design software tool (CSI-DESIGN CODE) which is under development by the CSI-ADM team at the NASA Langley Research Center. To date, all of these studies, irrespective of the type of integrated optimization posed or objectives and constraints used, have indicated that integrated controls-structures design results in an overall spacecraft design which is considerably superior to designs obtained through a conventional sequential approach. Consequently, it is believed that validation of some of these results through fabrication and testing of a structure which is designed through an integrated design approach is warranted. The objective of this paper is to present and discuss the efforts that have been taken thus far for the validation of the integrated design methodology.

  8. Combustor design and analysis using the Rocket Combustor Interactive Design (ROCCID) methodology

    NASA Technical Reports Server (NTRS)

    Klem, Mark D.; Pieper, Jerry L.; Walker, Richard E.

    1990-01-01

    The ROCket Combustor Interactive Design (ROCCID) Methodology is a newly developed, interactive computer code for the design and analysis of a liquid propellant rocket combustion chamber. The application of ROCCID to design a liquid rocket combustion chamber is illustrated. Designs for a 50,000 lbf thrust and 1250 psi chamber pressure combustor using liquid oxygen (LOX)RP-1 propellants are developed and evaluated. Tradeoffs between key design parameters affecting combustor performance and stability are examined. Predicted performance and combustion stability margin for these designs are provided as a function of the combustor operating mixture ratio and chamber pressure.

  9. Combustor design and analysis using the ROCket Combustor Interactive Design (ROCCID) Methodology

    NASA Technical Reports Server (NTRS)

    Klem, Mark D.; Pieper, Jerry L.; Walker, Richard E.

    1990-01-01

    The ROCket Combustor Interactive Design (ROCCID) Methodology is a newly developed, interactive computer code for the design and analysis of a liquid propellant rocket combustion chamber. The application of ROCCID to design a liquid rocket combustion chamber is illustrated. Designs for a 50,000 lbf thrust and 1250 psi chamber pressure combustor using liquid oxygen (LOX)RP-1 propellants are developed and evaluated. Tradeoffs between key design parameters affecting combustor performance and stability are examined. Predicted performance and combustion stability margin for these designs are provided as a function of the combustor operating mixture ratio and chamber pressure.

  10. Towards a Methodology for the Design of Multimedia Public Access Interfaces.

    ERIC Educational Resources Information Center

    Rowley, Jennifer

    1998-01-01

    Discussion of information systems methodologies that can contribute to interface design for public access systems covers: the systems life cycle; advantages of adopting information systems methodologies; soft systems methodologies; task-oriented approaches to user interface design; holistic design, the Star model, and prototyping; the…

  11. A design methodology for portable software on parallel computers

    NASA Technical Reports Server (NTRS)

    Nicol, David M.; Miller, Keith W.; Chrisman, Dan A.

    1993-01-01

    This final report for research that was supported by grant number NAG-1-995 documents our progress in addressing two difficulties in parallel programming. The first difficulty is developing software that will execute quickly on a parallel computer. The second difficulty is transporting software between dissimilar parallel computers. In general, we expect that more hardware-specific information will be included in software designs for parallel computers than in designs for sequential computers. This inclusion is an instance of portability being sacrificed for high performance. New parallel computers are being introduced frequently. Trying to keep one's software on the current high performance hardware, a software developer almost continually faces yet another expensive software transportation. The problem of the proposed research is to create a design methodology that helps designers to more precisely control both portability and hardware-specific programming details. The proposed research emphasizes programming for scientific applications. We completed our study of the parallelizability of a subsystem of the NASA Earth Radiation Budget Experiment (ERBE) data processing system. This work is summarized in section two. A more detailed description is provided in Appendix A ('Programming Practices to Support Eventual Parallelism'). Mr. Chrisman, a graduate student, wrote and successfully defended a Ph.D. dissertation proposal which describes our research associated with the issues of software portability and high performance. The list of research tasks are specified in the proposal. The proposal 'A Design Methodology for Portable Software on Parallel Computers' is summarized in section three and is provided in its entirety in Appendix B. We are currently studying a proposed subsystem of the NASA Clouds and the Earth's Radiant Energy System (CERES) data processing system. This software is the proof-of-concept for the Ph.D. dissertation. We have implemented and measured

  12. Bond energy analysis revisited and designed toward a rigorous methodology

    NASA Astrophysics Data System (ADS)

    Nakai, Hiromi; Ohashi, Hideaki; Imamura, Yutaka; Kikuchi, Yasuaki

    2011-09-01

    The present study theoretically revisits and numerically assesses two-body energy decomposition schemes including a newly proposed one. The new decomposition scheme is designed to make the equilibrium bond distance equivalent with the minimum point of bond energies. Although the other decomposition schemes generally predict the wrong order of the C-C bond strengths of C2H2, C2H4, and C2H6, the new decomposition scheme is capable of reproducing the C-C bond strengths. Numerical assessment on a training set of molecules demonstrates that the present scheme exhibits a stronger correlation with bond dissociation energies than the other decomposition schemes do, which suggests that the new decomposition scheme is a reliable and powerful analysis methodology.

  13. Sonic Boom Mitigation Through Aircraft Design and Adjoint Methodology

    NASA Technical Reports Server (NTRS)

    Rallabhandi, Siriam K.; Diskin, Boris; Nielsen, Eric J.

    2012-01-01

    This paper presents a novel approach to design of the supersonic aircraft outer mold line (OML) by optimizing the A-weighted loudness of sonic boom signature predicted on the ground. The optimization process uses the sensitivity information obtained by coupling the discrete adjoint formulations for the augmented Burgers Equation and Computational Fluid Dynamics (CFD) equations. This coupled formulation links the loudness of the ground boom signature to the aircraft geometry thus allowing efficient shape optimization for the purpose of minimizing the impact of loudness. The accuracy of the adjoint-based sensitivities is verified against sensitivities obtained using an independent complex-variable approach. The adjoint based optimization methodology is applied to a configuration previously optimized using alternative state of the art optimization methods and produces additional loudness reduction. The results of the optimizations are reported and discussed.

  14. Development of design and analysis methodology for composite bolted joints

    NASA Astrophysics Data System (ADS)

    Grant, Peter; Sawicki, Adam

    1991-05-01

    This paper summarizes work performed to develop composite joint design methodology for use on rotorcraft primary structure, determine joint characteristics which affect joint bearing and bypass strength, and develop analytical methods for predicting the effects of such characteristics in structural joints. Experimental results have shown that bearing-bypass interaction allowables cannot be defined using a single continuous function due to variance of failure modes for different bearing-bypass ratios. Hole wear effects can be significant at moderate stress levels and should be considered in the development of bearing allowables. A computer program has been developed and has successfully predicted bearing-bypass interaction effects for the (0/+/-45/90) family of laminates using filled hole and unnotched test data.

  15. A novel methodology for building robust design rules by using design based metrology (DBM)

    NASA Astrophysics Data System (ADS)

    Lee, Myeongdong; Choi, Seiryung; Choi, Jinwoo; Kim, Jeahyun; Sung, Hyunju; Yeo, Hyunyoung; Shim, Myoungseob; Jin, Gyoyoung; Chung, Eunseung; Roh, Yonghan

    2013-03-01

    This paper addresses a methodology for building robust design rules by using design based metrology (DBM). Conventional method for building design rules has been using a simulation tool and a simple pattern spider mask. At the early stage of the device, the estimation of simulation tool is poor. And the evaluation of the simple pattern spider mask is rather subjective because it depends on the experiential judgment of an engineer. In this work, we designed a huge number of pattern situations including various 1D and 2D design structures. In order to overcome the difficulties of inspecting many types of patterns, we introduced Design Based Metrology (DBM) of Nano Geometry Research, Inc. And those mass patterns could be inspected at a fast speed with DBM. We also carried out quantitative analysis on PWQ silicon data to estimate process variability. Our methodology demonstrates high speed and accuracy for building design rules. All of test patterns were inspected within a few hours. Mass silicon data were handled with not personal decision but statistical processing. From the results, robust design rules are successfully verified and extracted. Finally we found out that our methodology is appropriate for building robust design rules.

  16. SSME Investment in Turbomachinery Inducer Impeller Design Tools and Methodology

    NASA Technical Reports Server (NTRS)

    Zoladz, Thomas; Mitchell, William; Lunde, Kevin

    2010-01-01

    Within the rocket engine industry, SSME turbomachines are the de facto standards of success with regard to meeting aggressive performance requirements under challenging operational environments. Over the Shuttle era, SSME has invested heavily in our national inducer impeller design infrastructure. While both low and high pressure turbopump failures/anomaly resolution efforts spurred some of these investments, the SSME program was a major benefactor of key areas of turbomachinery inducer-impeller research outside of flight manifest pressures. Over the past several decades, key turbopump internal environments have been interrogated via highly instrumented hot-fire and cold-flow testing. Likewise, SSME has sponsored the advancement of time accurate and cavitating inducer impeller computation fluid dynamics (CFD) tools. These investments together have led to a better understanding of the complex internal flow fields within aggressive high performing inducers and impellers. New design tools and methodologies have evolved which intend to provide confident blade designs which strike an appropriate balance between performance and self induced load management.

  17. Design of integrated pitch axis for autopilot/autothrottle and integrated lateral axis for autopilot/yaw damper for NASA TSRV airplane using integral LQG methodology

    NASA Technical Reports Server (NTRS)

    Kaminer, Isaac; Benson, Russell A.; Coleman, Edward E.; Ebrahimi, Yaghoob S.

    1990-01-01

    Two designs are presented for control systems for the NASA Transport System Research Vehicle (TSRV) using integral Linear Quadratic Gaussian (LQG) methodology. The first is an integrated longitudinal autopilot/autothrottle design and the second design is an integrated lateral autopilot/yaw damper/sideslip controller design. It is shown that a systematic top-down approach to a complex design problem combined with proper application of modern control synthesis techniques yields a satisfactory solution in a reasonable period of time.

  18. An NAFP Project: Use of Object Oriented Methodologies and Design Patterns to Refactor Software Design

    NASA Technical Reports Server (NTRS)

    Shaykhian, Gholam Ali; Baggs, Rhoda

    2007-01-01

    In the early problem-solution era of software programming, functional decompositions were mainly used to design and implement software solutions. In functional decompositions, functions and data are introduced as two separate entities during the design phase, and are followed as such in the implementation phase. Functional decompositions make use of refactoring through optimizing the algorithms, grouping similar functionalities into common reusable functions, and using abstract representations of data where possible; all these are done during the implementation phase. This paper advocates the usage of object-oriented methodologies and design patterns as the centerpieces of refactoring software solutions. Refactoring software is a method of changing software design while explicitly preserving its external functionalities. The combined usage of object-oriented methodologies and design patterns to refactor should also benefit the overall software life cycle cost with improved software.

  19. A systematic approach to design for lifelong aircraft evolution

    NASA Astrophysics Data System (ADS)

    Lim, Dongwook

    This research proposes a systematic approach with which the decision makers can evaluate the value and risk of a new aircraft development program, including potential derivative development opportunities. The proposed Evaluation of Lifelong Vehicle Evolution (EvoLVE) method is a two- or multi-stage representation of the aircraft design process that accommodates initial development phases as well as follow-on phases. One of the key elements of this method is the Stochastic Programming with Recourse (SPR) technique, which accounts for uncertainties associated with future requirements. The remedial approach of SPR in its two distinctive problem-solving steps is well suited to aircraft design problems where derivatives, retrofits, and upgrades have been used to fix designs that were once but no longer optimal. The solution approach of SPR is complemented by the Risk-Averse Strategy Selection (RASS) technique to gauge risk associated with vehicle evolution options. In the absence of a full description of the random space, a scenario-based approach captures the randomness with a few probable scenarios and reveals implications of different future events. Last, an interactive framework for decision-making support allows simultaneous navigation of the current and future design space with a greater degree of freedom. A cantilevered beam design problem was set up and solved using the SPR technique to showcase its application to an engineering design setting. The full EvoLVE method was conducted on a notional multi-role fighter based on the F/A-18 Hornet.

  20. Preliminary methodology for design of stable drifts for the Yucca Mountain Project

    SciTech Connect

    Bauer, S.J.; Ehgartner, B.L.; Hardy, M.P.

    1989-12-31

    This paper defines a methodology and criteria by which the stability of underground repository drifts in tuff is determined and from which the ground support system is designed. Preconstruction evaluations of stability are required for planning and to support the license application process. The emphasis is on analytical numerical methods because, at this time, empirical data are generally not available for excavations in welded tuff at elevated temperatures or in seismic environments. Observational methods are only applicable during construction. The methodology suggests analytical techniques for the range of structural conditions of the rock currently expected at the Yucca Mountain site: systematically jointed rock masses, randomly jointed rock masses, and widely spaced discrete joints. The analyses must also load on the rock in the vicinity of excavations that result from in situ stresses, thermal expansion, and seismic events. Large-scale field experiments at the Exploratory Shaft Facility (ESF), and laboratory experiments on ESF samples define the controlling deformation mechanisms and allows evaluation of in situ properties, the methodology presented is expected to evolve. 2 refs., 2 figs.

  1. The Navigation Guide Systematic Review Methodology: A Rigorous and Transparent Method for Translating Environmental Health Science into Better Health Outcomes

    PubMed Central

    Sutton, Patrice

    2014-01-01

    Background: Synthesizing what is known about the environmental drivers of health is instrumental to taking prevention-oriented action. Methods of research synthesis commonly used in environmental health lag behind systematic review methods developed in the clinical sciences over the past 20 years. Objectives: We sought to develop a proof of concept of the “Navigation Guide,” a systematic and transparent method of research synthesis in environmental health. Discussion: The Navigation Guide methodology builds on best practices in research synthesis in evidence-based medicine and environmental health. Key points of departure from current methods of expert-based narrative review prevalent in environmental health include a prespecified protocol, standardized and transparent documentation including expert judgment, a comprehensive search strategy, assessment of “risk of bias,” and separation of the science from values and preferences. Key points of departure from evidence-based medicine include assigning a “moderate” quality rating to human observational studies and combining diverse evidence streams. Conclusions: The Navigation Guide methodology is a systematic and rigorous approach to research synthesis that has been developed to reduce bias and maximize transparency in the evaluation of environmental health information. Although novel aspects of the method will require further development and validation, our findings demonstrated that improved methods of research synthesis under development at the National Toxicology Program and under consideration by the U.S. Environmental Protection Agency are fully achievable. The institutionalization of robust methods of systematic and transparent review would provide a concrete mechanism for linking science to timely action to prevent harm. Citation: Woodruff TJ, Sutton P. 2014. The Navigation Guide systematic review methodology: a rigorous and transparent method for translating environmental health science into

  2. European COPD Audit: design, organisation of work and methodology.

    PubMed

    López-Campos, Jose Luis; Hartl, Sylvia; Pozo-Rodriguez, Francisco; Roberts, C Michael

    2013-02-01

    Clinical audit has an important role as an indicator of the clinical practice in a given community. The European Respiratory Society (ERS) chronic obstructive pulmonary disease (COPD) audit was designed as a pilot study to evaluate clinical practice variability as well as clinical and organisational factors related to outcomes for COPD hospital admissions across Europe. The study was designed as a prospective observational noninterventional cohort trial, in which 422 hospitals from 13 European countries participated. There were two databases: one for hospital's resources and organisation and one for clinical information. The study was comprised of an initial 8-week phase during which all consecutive cases admitted to hospital due to an exacerbation of COPD were identified and information on clinical practice was gathered. During the 90-day second phase, mortality and readmissions were recorded. Patient data were anonymised and encrypted through a multi-lingual web-tool. As there is no pan-European Ethics Committee for audits, all partners accepted the general ethical rules of the ERS and ensured compliance with their own national ethical requirements. This paper describes the methodological issues encountered in organising and delivering a multi-national European audit, highlighting goals, barriers and achievements, and provides valuable information for those interested in developing clinical audits. PMID:22599361

  3. Design Methodology of Long Complex Helium Cryogenic Transfer Lines

    NASA Astrophysics Data System (ADS)

    Fydrych, J.; Chorowski, M.; Polinski, J.; Skrzypacz, J.

    2010-04-01

    Big scientific facilities, like superconducting particle accelerators or fusion reactors require high cooling power, usually produced locally by large helium refrigerators and transferred, by means of liquid or supercritical helium, over the distances that may exceed several kilometres. Construction of cold helium transfer lines should take into consideration many different issues. The lines are exposed to thermal loads which can constitute an important part of the cryogenic system thermal budget. Pressure difference between the vacuum insulation and the inner content of the pipes causes significant mechanical stresses. The cyclic changes of temperature can lead to considerable fatigue stresses. Additionally, due to complex structure of the scientific facilities, the access to the cryogenic lines can be partly or totally limited. Therefore all these thermal and mechanical aspects have to be analyzed and compromised during the design phase of the complex helium transfer line. The paper presents a design methodology of long multi-channel helium cryogenic transfer lines. It describes some aspects of process line arrangement, thermo-mechanical calculation, supporting structure and contraction protection, taking as a case study cryogenic transfer line XATL1, dedicated for the Accelerator Module Test Facility (AMTF) of the European X-rays Free Electron Laser (XFEL).

  4. SysSon - A Framework for Systematic Sonification Design

    NASA Astrophysics Data System (ADS)

    Vogt, Katharina; Goudarzi, Visda; Holger Rutz, Hanns

    2015-04-01

    SysSon is a research approach on introducing sonification systematically to a scientific community where it is not yet commonly used - e.g., in climate science. Thereby, both technical and socio-cultural barriers have to be met. The approach was further developed with climate scientists, who participated in contextual inquiries, usability tests and a workshop of collaborative design. Following from these extensive user tests resulted our final software framework. As frontend, a graphical user interface allows climate scientists to parametrize standard sonifications with their own data sets. Additionally, an interactive shell allows to code new sonifications for users competent in sound design. The framework is a standalone desktop application, available as open source (for details see http://sysson.kug.ac.at/) and works with data in NetCDF format.

  5. We!Design: A Student-Centred Participatory Methodology for the Design of Educational Applications

    ERIC Educational Resources Information Center

    Triantafyllakos, George N.; Palaigeorgiou, George E.; Tsoukalas, Ioannis A.

    2008-01-01

    The development of educational applications has always been a challenging and complex issue, mainly because of the complications imposed by the cognitive and psychological aspects of student-computer interactions. This article presents a methodology, named We!Design, that tries to encounter the complexity of educational applications development…

  6. Architectural Exploration and Design Methodologies of Photonic Interconnection Networks

    NASA Astrophysics Data System (ADS)

    Chan, Jong Wu

    Photonic technology is becoming an increasingly attractive solution to the problems facing today's electronic chip-scale interconnection networks. Recent progress in silicon photonics research has enabled the demonstration of all the necessary optical building blocks for creating extremely high-bandwidth density and energy-efficient links for on- and off-chip communications. From the feasibility and architecture perspective however, photonics represents a dramatic paradigm shift from traditional electronic network designs due to fundamental differences in how electronics and photonics function and behave. As a result of these differences, new modeling and analysis methods must be employed in order to properly realize a functional photonic chip-scale interconnect design. In this work, we present a methodology for characterizing and modeling fundamental photonic building blocks which can subsequently be combined to form full photonic network architectures. We also describe a set of tools which can be utilized to assess the physical-layer and system-level performance properties of a photonic network. The models and tools are integrated in a novel open-source design and simulation environment called PhoenixSim. Next, we leverage PhoenixSim for the study of chip-scale photonic networks. We examine several photonic networks through the synergistic study of both physical-layer metrics and system-level metrics. This holistic analysis method enables us to provide deeper insight into architecture scalability since it considers insertion loss, crosstalk, and power dissipation. In addition to these novel physical-layer metrics, traditional system-level metrics of bandwidth and latency are also obtained. Lastly, we propose a novel routing architecture known as wavelength-selective spatial routing. This routing architecture is analogous to electronic virtual channels since it enables the transmission of multiple logical optical channels through a single physical plane (i.e. the

  7. Arab Teens Lifestyle Study (ATLS): objectives, design, methodology and implications

    PubMed Central

    Al-Hazzaa, Hazzaa M; Musaiger, Abdulrahman O

    2011-01-01

    Background There is a lack of comparable data on physical activity, sedentary behavior, and dietary habits among Arab adolescents, which limits our understanding and interpretation of the relationship between obesity and lifestyle parameters. Therefore, we initiated the Arab Teens Lifestyle Study (ATLS). The ATLS is a multicenter collaborative project for assessing lifestyle habits of Arab adolescents. The objectives of the ATLS project were to investigate the prevalence rates for overweight and obesity, physical activity, sedentary activity and dietary habits among Arab adolescents, and to examine the interrelationships between these lifestyle variables. This paper reports on the objectives, design, methodology, and implications of the ATLS. Design/Methods The ATLS is a school-based cross-sectional study involving 9182 randomly selected secondary-school students (14–19 years) from major Arab cities, using a multistage stratified sampling technique. The participating Arab cities included Riyadh, Jeddah, and Al-Khobar (Saudi Arabia), Bahrain, Dubai (United Arab Emirates), Kuwait, Amman (Jordan), Mosel (Iraq), Muscat (Oman), Tunisia (Tunisia) and Kenitra (Morocco). Measured variables included anthropometric measurements, physical activity, sedentary behavior, sleep duration, and dietary habits. Discussion The ATLS project will provide a unique opportunity to collect and analyze important lifestyle information from Arab adolescents using standardized procedures. This is the first time a collaborative Arab project will simultaneously assess broad lifestyle variables in a large sample of adolescents from numerous urbanized Arab regions. This joint research project will supply us with comprehensive and recent data on physical activity/inactivity and eating habits of Arab adolescents relative to obesity. Such invaluable lifestyle-related data are crucial for developing public health policies and regional strategies for health promotion and disease prevention. PMID

  8. Using systematic reviews for evidence-based health promotion: basic methodology issues.

    PubMed

    Buendía-Rodríguez, Jefferson A; Sánchez-Villamil, Juana P

    2006-12-01

    Systematic reviews and evidence-based recommendations are becoming increasingly important for decision-making in health and medicine. Systematic reviews of population-health interventions are challenging and methods will continue evolving. This paper provides an overview of how evidence-based approaches in public health and health promotion are being reviewed to provide a basis for Colombian Guide to Health Promotion, analysing limitations and recommendations for future reviews. PMID:17361581

  9. Using the systematic review methodology to evaluate factors that influence the persistence of influenza virus in environmental matrices.

    PubMed

    Irwin, C K; Yoon, K J; Wang, C; Hoff, S J; Zimmerman, J J; Denagamage, T; O'Connor, A M

    2011-02-01

    Understanding factors that influence persistence of influenza virus in an environment without host animals is critical to appropriate decision-making for issues such as quarantine downtimes, setback distances, and eradication programs in livestock production systems. This systematic review identifies literature describing persistence of influenza virus in environmental samples, i.e., air, water, soil, feces, and fomites. An electronic search of PubMed, CAB, AGRICOLA, Biosis, and Compendex was performed, and citation relevance was determined according to the aim of the review. Quality assessment of relevant studies was performed using criteria from experts in virology, disease ecology, and environmental science. A total of 9,760 abstracts were evaluated, and 40 appeared to report the persistence of influenza virus in environmental samples. Evaluation of full texts revealed that 19 of the 40 studies were suitable for review, as they described virus concentration measured at multiple sampling times, with viruses detectable at least twice. Seven studies reported persistence in air (six published before 1970), seven in water (five published after 1990), two in feces, and three on surfaces. All three fomite and five air studies addressed human influenza virus, and all water and feces studies pertained to avian influenza virus. Outcome measurements were transformed to half-lives, and resultant multivariate mixed linear regression models identified influenza virus surviving longer in water than in air. Temperature was a significant predictor of persistence over all matrices. Salinity and pH were significant predictors of persistence in water conditions. An assessment of the methodological quality review of the included studies revealed significant gaps in reporting critical aspects of study design. PMID:21148699

  10. New systematic methodology for incorporating dynamic heat transfer modelling in multi-phase biochemical reactors.

    PubMed

    Fernández-Arévalo, T; Lizarralde, I; Grau, P; Ayesa, E

    2014-09-01

    This paper presents a new modelling methodology for dynamically predicting the heat produced or consumed in the transformations of any biological reactor using Hess's law. Starting from a complete description of model components stoichiometry and formation enthalpies, the proposed modelling methodology has integrated successfully the simultaneous calculation of both the conventional mass balances and the enthalpy change of reaction in an expandable multi-phase matrix structure, which facilitates a detailed prediction of the main heat fluxes in the biochemical reactors. The methodology has been implemented in a plant-wide modelling methodology in order to facilitate the dynamic description of mass and heat throughout the plant. After validation with literature data, as illustrative examples of the capability of the methodology, two case studies have been described. In the first one, a predenitrification-nitrification dynamic process has been analysed, with the aim of demonstrating the easy integration of the methodology in any system. In the second case study, the simulation of a thermal model for an ATAD has shown the potential of the proposed methodology for analysing the effect of ventilation and influent characterization. PMID:24852412

  11. Aerospace engineering design by systematic decomposition and multilevel optimization

    NASA Technical Reports Server (NTRS)

    Sobieszczanski-Sobieski, J.; Barthelemy, J. F. M.; Giles, G. L.

    1984-01-01

    A method for systematic analysis and optimization of large engineering systems, by decomposition of a large task into a set of smaller subtasks that is solved concurrently is described. The subtasks may be arranged in hierarchical levels. Analyses are carried out in each subtask using inputs received from other subtasks, and are followed by optimizations carried out from the bottom up. Each optimization at the lower levels is augmented by analysis of its sensitivity to the inputs received from other subtasks to account for the couplings among the subtasks in a formal manner. The analysis and optimization operations alternate iteratively until they converge to a system design whose performance is maximized with all constraints satisfied. The method, which is still under development, is tentatively validated by test cases in structural applications and an aircraft configuration optimization.

  12. Multidisciplinary design and optimization (MDO) methodology for the aircraft conceptual design

    NASA Astrophysics Data System (ADS)

    Iqbal, Liaquat Ullah

    An integrated design and optimization methodology has been developed for the conceptual design of an aircraft. The methodology brings higher fidelity Computer Aided Design, Engineering and Manufacturing (CAD, CAE and CAM) Tools such as CATIA, FLUENT, ANSYS and SURFCAM into the conceptual design by utilizing Excel as the integrator and controller. The approach is demonstrated to integrate with many of the existing low to medium fidelity codes such as the aerodynamic panel code called CMARC and sizing and constraint analysis codes, thus providing the multi-fidelity capabilities to the aircraft designer. The higher fidelity design information from the CAD and CAE tools for the geometry, aerodynamics, structural and environmental performance is provided for the application of the structured design methods such as the Quality Function Deployment (QFD) and the Pugh's Method. The higher fidelity tools bring the quantitative aspects of a design such as precise measurements of weight, volume, surface areas, center of gravity (CG) location, lift over drag ratio, and structural weight, as well as the qualitative aspects such as external geometry definition, internal layout, and coloring scheme early in the design process. The performance and safety risks involved with the new technologies can be reduced by modeling and assessing their impact more accurately on the performance of the aircraft. The methodology also enables the design and evaluation of the novel concepts such as the blended (BWB) and the hybrid wing body (HWB) concepts. Higher fidelity computational fluid dynamics (CFD) and finite element analysis (FEA) allow verification of the claims for the performance gains in aerodynamics and ascertain risks of structural failure due to different pressure distribution in the fuselage as compared with the tube and wing design. The higher fidelity aerodynamics and structural models can lead to better cost estimates that help reduce the financial risks as well. This helps in

  13. A combined stochastic feedforward and feedback control design methodology with application to autoland design

    NASA Technical Reports Server (NTRS)

    Halyo, Nesim

    1987-01-01

    A combined stochastic feedforward and feedback control design methodology was developed. The objective of the feedforward control law is to track the commanded trajectory, whereas the feedback control law tries to maintain the plant state near the desired trajectory in the presence of disturbances and uncertainties about the plant. The feedforward control law design is formulated as a stochastic optimization problem and is embedded into the stochastic output feedback problem where the plant contains unstable and uncontrollable modes. An algorithm to compute the optimal feedforward is developed. In this approach, the use of error integral feedback, dynamic compensation, control rate command structures are an integral part of the methodology. An incremental implementation is recommended. Results on the eigenvalues of the implemented versus designed control laws are presented. The stochastic feedforward/feedback control methodology is used to design a digital automatic landing system for the ATOPS Research Vehicle, a Boeing 737-100 aircraft. The system control modes include localizer and glideslope capture and track, and flare to touchdown. Results of a detailed nonlinear simulation of the digital control laws, actuator systems, and aircraft aerodynamics are presented.

  14. Systematic methodology for estimating direct capital costs for blanket tritium processing systems

    SciTech Connect

    Finn, P.A.

    1985-01-01

    This paper describes the methodology developed for estimating the relative capital costs of blanket processing systems. The capital costs of the nine blanket concepts selected in the Blanket Comparison and Selection Study are presented and compared.

  15. Risk of bias and methodological appraisal practices in systematic reviews published in anaesthetic journals: a meta-epidemiological study.

    PubMed

    Detweiler, B N; Kollmorgen, L E; Umberham, B A; Hedin, R J; Vassar, B M

    2016-08-01

    The validity of primary study results included in systematic reviews plays an important role in drawing conclusions about intervention effectiveness and carries implications for clinical decision-making. We evaluated the prevalence of methodological quality and risk of bias assessments in systematic reviews published in the five highest-ranked anaesthesia journals since 2007. The initial PubMed search yielded 315 citations, and our final sample after screening consisted of 207 systematic reviews. One hundred and seventy-four reviews conducted methodological quality/risk of bias analyses. The Jadad scale was most frequently used. Forty-four of the 83 reviews that included high risk of bias studies re-analysed their data omitting these trials: 20 showed differences in pooled effect estimates. Reviews containing a greater number of primary studies evaluated quality less frequently than smaller reviews. Overall, the majority of reviews evaluated bias; however, many applied questionable methods. Given the potential effects of bias on summary outcomes, greater attention is warranted. PMID:27396249

  16. Methodology for the optimal design of an integrated first and second generation ethanol production plant combined with power cogeneration.

    PubMed

    Bechara, Rami; Gomez, Adrien; Saint-Antonin, Valérie; Schweitzer, Jean-Marc; Maréchal, François

    2016-08-01

    The application of methodologies for the optimal design of integrated processes has seen increased interest in literature. This article builds on previous works and applies a systematic methodology to an integrated first and second generation ethanol production plant with power cogeneration. The methodology breaks into process simulation, heat integration, thermo-economic evaluation, exergy efficiency vs. capital costs, multi-variable, evolutionary optimization, and process selection via profitability maximization. Optimization generated Pareto solutions with exergy efficiency ranging between 39.2% and 44.4% and capital costs from 210M$ to 390M$. The Net Present Value was positive for only two scenarios and for low efficiency, low hydrolysis points. The minimum cellulosic ethanol selling price was sought to obtain a maximum NPV of zero for high efficiency, high hydrolysis alternatives. The obtained optimal configuration presented maximum exergy efficiency, hydrolyzed bagasse fraction, capital costs and ethanol production rate, and minimum cooling water consumption and power production rate. PMID:27160954

  17. A Synergy between the Technological Process and a Methodology for Web Design: Implications for Technological Problem Solving and Design

    ERIC Educational Resources Information Center

    Jakovljevic, Maria; Ankiewicz, Piet; De swardt, Estelle; Gross, Elna

    2004-01-01

    Traditional instructional methodology in the Information System Design (ISD) environment lacks explicit strategies for promoting the cognitive skills of prospective system designers. This contributes to the fragmented knowledge and low motivational and creative involvement of learners in system design tasks. In addition, present ISD methodologies,…

  18. A multi-stage, multi-response Bayesian methodology for surrogate modeling in engineering design

    NASA Astrophysics Data System (ADS)

    Romero, David A.

    To design products, designers often need models of the system behavior as a function of a set of input (or design) variables; these models allow designers to learn about the influence of different design variables on the system's performance. In practice, however, system models are either unavailable or expensive to evaluate and thus unsuited for systematic use in preliminary design. Creation of surrogate models, or metamodels, of system behavior is a common approach that has been proposed to circumvent these problems. In this work in engineering design based on computer experiments with multiple performance criteria, we propose the creation of multi-response metamodels to model several metrics of system behavior jointly, instead of modeling each individually. In particular, we develop the Multi-stage, Multi-Response Bayesian Surrogate Models (MMRBSM) methodology, a flexible, multi-stage framework that allows for modeling the correlation among different response variables for their simultaneous prediction, while also enabling the integration of different sources of information about the response values into a single, global model of the system's responses. In this thesis, the mathematical formulation of MMRBSM metamodels is developed, including the required multi-stage, multi-response covariance functions and multi-response adaptive sampling techniques. The proposed metamodeling framework is tested, first with commonly-used, analytical test functions and then in the engineering design of an electronic device based on multiple performance metrics. Results indicate that the proposed MMRBSM outperforms individual metamodels, though the relative performance depends on the sample size, the sampling method and the true correlation among the observed response values. Results also indicate that the proposed multi-stage formulation enables the incorporation of expert knowledge into the multi-response metamodels, leading to order-of-magnitude improvements in the predictive

  19. A rational design change methodology based on experimental and analytical modal analysis

    SciTech Connect

    Weinacht, D.J.; Bennett, J.G.

    1993-08-01

    A design methodology that integrates analytical modeling and experimental characterization is presented. This methodology represents a powerful tool for making rational design decisions and changes. An example of its implementation in the design, analysis, and testing of a precisions machine tool support structure is given.

  20. Reporting of financial and non-financial conflicts of interest by authors of systematic reviews: a methodological survey

    PubMed Central

    Anouti, Sirine; Al-Gibbawi, Mounir; Abou-Jaoude, Elias A; Hasbani, Divina Justina; Guyatt, Gordon; Akl, Elie A

    2016-01-01

    Background Conflicts of interest may bias the findings of systematic reviews. The objective of this methodological survey was to assess the frequency and different types of conflicts of interest that authors of Cochrane and non-Cochrane systematic reviews report. Methods We searched for systematic reviews using the Cochrane Database of Systematic Reviews and Ovid MEDLINE (limited to the 119 Core Clinical Journals and the year 2015). We defined a conflict of interest disclosure as the reporting of whether a conflict of interest exists or not, and used a framework to classify conflicts of interest into individual (financial, professional and intellectual) and institutional (financial and advocatory) conflicts of interest. We conducted descriptive and regression analyses. Results Of the 200 systematic reviews, 194 (97%) reported authors' conflicts of interest disclosures, typically in the main document, and in a few cases either online (2%) or on request (5%). Of the 194 Cochrane and non-Cochrane reviews, 49% and 33%, respectively, had at least one author reporting any type of conflict of interest (p=0.023). Institutional conflicts of interest were less frequently reported than individual conflicts of interest, and Cochrane reviews were more likely to report individual intellectual conflicts of interest compared with non-Cochrane reviews (19% and 5%, respectively, p=0.004). Regression analyses showed a positive association between reporting of conflicts of interest (at least one type of conflict of interest, individual financial conflict of interest, institutional financial conflict of interest) and journal impact factor and between reporting individual financial conflicts of interest and pharmacological versus non-pharmacological intervention. Conclusions Although close to half of the published systematic reviews report that authors (typically many) have conflicts of interest, more than half report that they do not. Authors reported individual conflicts of interest

  1. Design guided data analysis for summarizing systematic pattern defects and process window

    NASA Astrophysics Data System (ADS)

    Xie, Qian; Venkatachalam, Panneerselvam; Lee, Julie; Chen, Zhijin; Zafar, Khurram

    2016-03-01

    As the semiconductor process technology moves into more advanced nodes, design and process induced systematic defects become increasingly significant yield limiters. Therefore, early detection of these defects is crucial. Focus Exposure Matrix (FEM) and Process Window Qualification (PWQ) are routine methods for discovering systematic patterning defects and establishing the lithography process window. These methods require the stepper to expose a reticle onto the wafer at various focus and exposure settings (also known as modulations). The wafer is subsequently inspected by a bright field, broadband plasma or an E-Beam Inspection tool using a high sensitivity inspection recipe (i.e. hot scan) that often reports a million or more defects. Analyzing this vast stream of data to identify the weak patterns and arrive at the optimal focus/exposure settings requires a significant amount of data reduction through aggressive sampling and nuisance filtering schemes. However, these schemes increase alpha risk, i.e. the probability of not catching some systematic or otherwise important defects within a modulation and thus reporting that modulation as a good condition for production wafers. In order to reduce this risk and establish a more accurate process window, we describe a technique that introduces image-and-design integration methodologies into the inspection data analysis workflow. These image-and-design integration methodologies include contour extraction and alignment to design, contour-to-design defect detection, defective/nuisance pattern retrieval, confirmed defective/nuisance pattern overlay with inspection data, and modulation-related weak-pattern ranking. The technique we present provides greater automation, from defect detection to defective pattern retrieval to decision-making steps, that allows for statistically summarized results and increased coverage of the wafer to be achieved without an adverse impact on cycle time. Statistically summarized results, lead

  2. [Marxism as a theoretical and methodological framework in collective health: implications for systematic review and synthesis of evidence].

    PubMed

    Soares, Cassia Baldini; Campos, Celia Maria Sivalli; Yonekura, Tatiana

    2013-12-01

    In this study, we discuss the integration in systematic reviews of research developed from a Marxist perspective of knowledge production and their results as evidence in healthcare. The study objectives are to review the assumptions of dialectical and historical materialism (DHM) and discuss the implications of dialectics for a literature review and the synthesis of evidence. DHM is a powerful framework for knowledge generation and transformation of policies and practices in healthcare. It assumes that social contradictions underlie the health-disease process, the fundamental theoretical construction in the field of collective health. Currently, we observe a considerable influence of the critical paradigm, of Marxist origin, in the construction of knowledge in health. Studies based on this critical paradigm incorporate complex methods, which are inherent to the guidelines of dialect, to identify the object and arrive at results that constitute evidence in healthcare. Systematic reviews should address the methodological difficulties associated with entirely integrating these results to healthcare. PMID:24626368

  3. Methodological quality of systematic reviews and clinical trials on women's health published in a Brazilian evidence-based health journal

    PubMed Central

    Macedo, Cristiane Rufino; Riera, Rachel; Torloni, Maria Regina

    2013-01-01

    OBJECTIVES: To assess the quality of systematic reviews and clinical trials on women's health recently published in a Brazilian evidence-based health journal. METHOD: All systematic reviews and clinical trials on women's health published in the last five years in the Brazilian Journal of Evidence-based Health were retrieved. Two independent reviewers critically assessed the methodological quality of reviews and trials using AMSTAR and the Cochrane Risk of Bias Table, respectively. RESULTS: Systematic reviews and clinical trials accounted for less than 10% of the 61 original studies on women's health published in the São Paulo Medical Journal over the last five years. All five reviews were considered to be of moderate quality; the worst domains were publication bias and the appropriate use of study quality in formulating conclusions. All three clinical trials were judged to have a high risk of bias. The participant blinding, personnel and outcome assessors and allocation concealment domains had the worst scores. CONCLUSIONS: Most of the systematic reviews and clinical trials on women's health recently published in a Brazilian evidence-based journal are of low to moderate quality. The quality of these types of studies needs improvement. PMID:23778332

  4. SOME RECENT IDEAS IN RESEARCH METHODOLOGY--FACET DESIGN AND THEORY OF DATA.

    ERIC Educational Resources Information Center

    RUNKEL, PHILIP J.

    FACET DESIGN, AS ORIGINATED BY LOUIS GUTTMAN, IS A METHOD OF SYSTEMATICALLY ORDERING A PROBLEM FOR RESEARCH. FACET ANALYSIS ENABLES THE VALIDITY OF AN ASSESSMENT OF THE ORDERING PROCESS TO BE TESTED. THE LOGIC OF FACET DESIGN AND ANALYSIS IS BASED UPON SYSTEMATIC DELINEATION OF THE IMPORTANT VARIABLES PRIOR TO DATA COLLECTION AND THE EVALUATION OF…

  5. A performance-oriented power transformer design methodology using multi-objective evolutionary optimization.

    PubMed

    Adly, Amr A; Abd-El-Hafiz, Salwa K

    2015-05-01

    Transformers are regarded as crucial components in power systems. Due to market globalization, power transformer manufacturers are facing an increasingly competitive environment that mandates the adoption of design strategies yielding better performance at lower costs. In this paper, a power transformer design methodology using multi-objective evolutionary optimization is proposed. Using this methodology, which is tailored to be target performance design-oriented, quick rough estimation of transformer design specifics may be inferred. Testing of the suggested approach revealed significant qualitative and quantitative match with measured design and performance values. Details of the proposed methodology as well as sample design results are reported in the paper. PMID:26257939

  6. A novel integrated framework and improved methodology of computer-aided drug design.

    PubMed

    Chen, Calvin Yu-Chian

    2013-01-01

    Computer-aided drug design (CADD) is a critical initiating step of drug development, but a single model capable of covering all designing aspects remains to be elucidated. Hence, we developed a drug design modeling framework that integrates multiple approaches, including machine learning based quantitative structure-activity relationship (QSAR) analysis, 3D-QSAR, Bayesian network, pharmacophore modeling, and structure-based docking algorithm. Restrictions for each model were defined for improved individual and overall accuracy. An integration method was applied to join the results from each model to minimize bias and errors. In addition, the integrated model adopts both static and dynamic analysis to validate the intermolecular stabilities of the receptor-ligand conformation. The proposed protocol was applied to identifying HER2 inhibitors from traditional Chinese medicine (TCM) as an example for validating our new protocol. Eight potent leads were identified from six TCM sources. A joint validation system comprised of comparative molecular field analysis, comparative molecular similarity indices analysis, and molecular dynamics simulation further characterized the candidates into three potential binding conformations and validated the binding stability of each protein-ligand complex. The ligand pathway was also performed to predict the ligand "in" and "exit" from the binding site. In summary, we propose a novel systematic CADD methodology for the identification, analysis, and characterization of drug-like candidates. PMID:23651478

  7. Appraisal of the methodological quality and summary of the findings of systematic reviews on the relationship between SSRIs and suicidality

    PubMed Central

    LI, Wei; LI, Wei; WAN, Yumei; REN, Juanjuan; LI, Ting; LI, Chunbo

    2014-01-01

    Background Several systematic reviews have been published about the relationship of the use of selective serotonin reuptake inhibitors (SSRIs) and risk of suicidal ideation or behavior but there has been no formal assessment of the quality of these reports. Aim Assess the methodological quality of systematic reviews about the relationship of SSRI use and suicidal ideation and behavior; and provide overall conclusions based on this assessment. Methods Systematic reviews of RCTs that compared SSRIs to placebo and used suicidal ideation or behavior as a key outcome variable were identified by searching Pubmed, Embase, The Cochrane Library, EBSCO, PsycINFO, Chinese National Knowledge Infrastructure, Chongqing VIP database for Chinese Technical Periodicals, WANFANG DATA, and the Chinese Biological Medical Literature Database. The methodological quality of included reviews was independently assessed by two expert raters using the 11-item Assessment of Multiple Systematic Reviews (AMSTAR) scale. Results Twelve systematic reviews and meta-analyses were identified. The inter-rater reliability of the overall AMSTAR quality score was excellent (ICC=0.86) but the inter-rater reliability of 5 of the 11 AMSTAR items was poor (Kappa <0.60). Based on the AMSTAR total score, there was one high-quality review, eight moderate-quality reviews, and three low-quality reviews. The high-quality review and three of the moderate-quality reviews reported a significantly increased risk of suicidal ideation or behavior in the SSRI group compared to the placebo group. Three of the four reviews limited to children and adolescents found a significantly increased risk of suicidal ideation or behavior with SSRI use which was most evident in teenagers taking paroxetine and in teenagers with depressive disorders. Conclusions The available evidence suggests that adolescents may experience an increase in suicidal ideation and behavior with SSRI use, particularly those who have a depressive disorder and

  8. A systematic review and analysis of factors associated with methodological quality in laparoscopic randomized controlled trials.

    PubMed

    Antoniou, Stavros Athanasios; Andreou, Alexandros; Antoniou, George Athanasios; Bertsias, Antonios; Köhler, Gernot; Koch, Oliver Owen; Pointner, Rudolph; Granderath, Frank-Alexander

    2015-01-01

    Several methods for assessment of methodological quality in randomized controlled trials (RCTs) have been developed during the past few years. Factors associated with quality in laparoscopic surgery have not been defined till date. The aim of this study was to investigate the relationship between bibliometric and the methodological quality of laparoscopic RCTs. The PubMed search engine was queried to identify RCTs on minimally invasive surgery published in 2012 in the 10 highest impact factor surgery journals and the 5 highest impact factor laparoscopic journals. Eligible studies were blindly assessed by two independent investigators using the Scottish Intercollegiate Guidelines Network (SIGN) tool for RCTs. Univariate and multivariate analyses were performed to identify potential associations with methodological quality. A total of 114 relevant RCTs were identified. More than half of the trials were of high or acceptable quality. Half of the reports provided information on comparative demo graphic data and only 21% performed intention-to-treat analysis. RCTs with sample size of at least 60 patients presented higher methodological quality (p = 0.025). Upon multiple regression, reporting on preoperative care and the experience level of surgeons were independent factors of quality. PMID:25896540

  9. Nominating under Constraints: A Systematic Comparison of Unlimited and Limited Peer Nomination Methodologies in Elementary School

    ERIC Educational Resources Information Center

    Gommans, Rob; Cillessen, Antonius H. N.

    2015-01-01

    Children's peer relationships are frequently assessed with peer nominations. An important methodological issue is whether to collect unlimited or limited nominations. Some researchers have argued that the psychometric differences between both methods are negligible, while others have claimed that one is superior over the other. The current…

  10. A Systematic Review of Brief Functional Analysis Methodology with Typically Developing Children

    ERIC Educational Resources Information Center

    Gardner, Andrew W.; Spencer, Trina D.; Boelter, Eric W.; DuBard, Melanie; Jennett, Heather K.

    2012-01-01

    Brief functional analysis (BFA) is an abbreviated assessment methodology derived from traditional extended functional analysis methods. BFAs are often conducted when time constraints in clinics, schools or homes are of concern. While BFAs have been used extensively to identify the function of problem behavior for children with disabilities, their…

  11. Design methodology of the strength properties of medical knitted meshes

    NASA Astrophysics Data System (ADS)

    Mikołajczyk, Z.; Walkowska, A.

    2016-07-01

    One of the most important utility properties of medical knitted meshes intended for hernia and urological treatment is their bidirectional strength along the courses and wales. The value of this parameter, expected by the manufacturers and surgeons, is estimated at 100 N per 5 cm of the sample width. The most frequently, these meshes are produced on the basis of single- or double-guide stitches. They are made of polypropylene and polyester monofilament yarns with the diameter in the range from 0.6 to 1.2 mm, characterized by a high medical purity. The aim of the study was to develop the design methodology of meshes strength based on the geometrical construction of the stitch and strength of yarn. In the environment of the ProCAD warpknit 5 software the simulated stretching process of meshes together with an analysis of their geometry changes was carried out. Simulations were made for four selected representative stitches. Both on a built, unique measuring position and on the tensile testing machine the real parameters of the loops geometry of meshes were measured. Model of mechanical stretching of warp-knitted meshes along the courses and wales was developed. The thesis argument was made, that the force that breaks the loop of warp-knitted fabric is the lowest value of breaking forces of loop link yarns or yarns that create straight sections of loop. This thesis was associate with the theory of strength that uses the “the weakest link concept”. Experimental verification of model was carried out for the basic structure of the single-guide mesh. It has been shown that the real, relative strength of the mesh related to one course is equal to the strength of the yarn breakage in a loop, while the strength along the wales is close to breaking strength of a single yarn. In relation to the specific construction of the medical mesh, based on the knowledge of the density of the loops structure, the a-jour mesh geometry and the yarns strength, it is possible, with high

  12. Staffing by Design: A Methodology for Staffing Reference

    ERIC Educational Resources Information Center

    Ward, David; Phetteplace, Eric

    2012-01-01

    The growth in number and kind of online reference services has resulted in both new users consulting library research services as well as new patterns of service use. Staffing in-person and virtual reference services desks adequately requires a systematic analysis of patterns of use across service points in order to successfully meet fluctuating…

  13. USDA Nutrition Evidence Library: methodology used to identify topics and develop systematic review questions for the birth-to-24-mo population.

    PubMed

    Obbagy, Julie E; Blum-Kemelor, Donna M; Essery, Eve V; Lyon, Joan M G; Spahn, Joanne M

    2014-03-01

    The USDA's Nutrition Evidence Library (NEL) specializes in conducting food- and nutrition-related systematic reviews that are used to inform federal government decision making. To ensure the utility of NEL systematic reviews, the most relevant topics must be addressed, questions must be clearly focused and appropriate in scope, and review frameworks must reflect the state of the science. Identifying the optimal topics and questions requires input from a variety of stakeholders, including scientists with technical expertise, as well as government policy and program leaders. The objective of this article is to describe the rationale and NEL methodology for identifying topics and developing systematic review questions implemented as part of the "Evaluating the evidence base to support the inclusion of infants and children from birth to 24 months of age in the Dietary Guidelines for Americans--the B-24 Project." This is the first phase of a larger project designed to develop dietary guidance for the birth to 24-mo population in the United States. PMID:24452234

  14. A Formal Semantics for the SRI Hierarchical Program Design Methodology

    NASA Technical Reports Server (NTRS)

    Boyer, R. S.; Moore, J. S.

    1983-01-01

    A formal statement of what it means to use (a subset of) the methodology is presented. It is formally defined that some specified module exists and what it means to say that another module is paid correctly implemented on top of it. No attention is to motivation, either of the methodology or of the formal development of it. Concentration is entirely upon mathematical succinctness and precision. A discussion is presented of how to use certain INTERLISP programs which implement the formal definitions. Among these are a program which generates Floyd like verification conditions sufficient to imply the correctness of a module implementation.

  15. Peer Review of a Formal Verification/Design Proof Methodology

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The role of formal verification techniques in system validation was examined. The value and the state of the art of performance proving for fault-tolerant compuers were assessed. The investigation, development, and evaluation of performance proving tools were reviewed. The technical issues related to proof methodologies are examined. The technical issues discussed are summarized.

  16. Visual Methodology in Classroom Inquiry: Enhancing Complementary Qualitative Research Designs

    ERIC Educational Resources Information Center

    Kingsley, Joanne

    2009-01-01

    This article presents the argument that combining visual methods with other qualitative research methods enhances the inherent strengths of each methodology and allows new understandings to emerge. These would otherwise remain hidden if only one method were used in isolation. In a qualitative inquiry of an elementary teacher's constructivist…

  17. Behavioral Methodology for Designing and Evaluating Applied Programs for Women.

    ERIC Educational Resources Information Center

    Thurston, Linda P.

    To be maximally effective in solving problems, researchers must place their methodological and theoretical models of science within social and political contexts. They must become aware of biases and assumptions and move toward a more valid perception of social realities. Psychologists must view women in the situational context within which…

  18. Integrated Controls-Structures Design Methodology for Flexible Spacecraft

    NASA Technical Reports Server (NTRS)

    Maghami, P. G.; Joshi, S. M.; Price, D. B.

    1995-01-01

    This paper proposes an approach for the design of flexible spacecraft, wherein the structural design and the control system design are performed simultaneously. The integrated design problem is posed as an optimization problem in which both the structural parameters and the control system parameters constitute the design variables, which are used to optimize a common objective function, thereby resulting in an optimal overall design. The approach is demonstrated by application to the integrated design of a geostationary platform, and to a ground-based flexible structure experiment. The numerical results obtained indicate that the integrated design approach generally yields spacecraft designs that are substantially superior to the conventional approach, wherein the structural design and control design are performed sequentially.

  19. Using QALYs in telehealth evaluations: a systematic review of methodology and transparency

    PubMed Central

    2014-01-01

    Background The quality-adjusted life-year (QALY) is a recognised outcome measure in health economic evaluations. QALY incorporates individual preferences and identifies health gains by combining mortality and morbidity into one single index number. A literature review was conducted to examine and discuss the use of QALYs to measure outcomes in telehealth evaluations. Methods Evaluations were identified via a literature search in all relevant databases. Only economic evaluations measuring both costs and QALYs using primary patient level data of two or more alternatives were included. Results A total of 17 economic evaluations estimating QALYs were identified. All evaluations used validated generic health related-quality of life (HRQoL) instruments to describe health states. They used accepted methods for transforming the quality scores into utility values. The methodology used varied between the evaluations. The evaluations used four different preference measures (EQ-5D, SF-6D, QWB and HUI3), and utility scores were elicited from the general population. Most studies reported the methodology used in calculating QALYs. The evaluations were less transparent in reporting utility weights at different time points and variability around utilities and QALYs. Few made adjustments for differences in baseline utilities. The QALYs gained in the reviewed evaluations varied from 0.001 to 0.118 in implying a small but positive effect of telehealth intervention on patient’s health. The evaluations reported mixed cost-effectiveness results. Conclusion The use of QALYs in telehealth evaluations has increased over the last few years. Different methodologies and utility measures have been used to calculate QALYs. A more harmonised methodology and utility measure is needed to ensure comparability across telehealth evaluations. PMID:25086443

  20. Prelimary methodology for design of stable drifts for the Yucca Mountain Project

    SciTech Connect

    Bauer, S.J.; Ehgartner, B.L.; Hardy, M.P.

    1990-10-01

    This paper discusses the Yucca Mountain Project which is investigating the feasibility of locating a high-level radioactive nuclear waste repository at Yucca Mountain, Nevada. The conceptual design of the repository is described. The design methodology is presented.

  1. Methodology for designing accelerated aging tests for predicting life of photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Gaines, G. B.; Thomas, R. E.; Derringer, G. C.; Kistler, C. W.; Bigg, D. M.; Carmichael, D. C.

    1977-01-01

    A methodology for designing aging tests in which life prediction was paramount was developed. The methodology builds upon experience with regard to aging behavior in those material classes which are expected to be utilized as encapsulant elements, viz., glasses and polymers, and upon experience with the design of aging tests. The experiences were reviewed, and results are discussed in detail.

  2. 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…

  3. Game Methodology for Design Methods and Tools Selection

    ERIC Educational Resources Information Center

    Ahmad, Rafiq; Lahonde, Nathalie; Omhover, Jean-françois

    2014-01-01

    Design process optimisation and intelligence are the key words of today's scientific community. A proliferation of methods has made design a convoluted area. Designers are usually afraid of selecting one method/tool over another and even expert designers may not necessarily know which method is the best to use in which circumstances. This…

  4. Total synthesis of vinblastine, related natural products, and key analogues and development of inspired methodology suitable for the systematic study of their structure-function properties.

    PubMed

    Sears, Justin E; Boger, Dale L

    2015-03-17

    Biologically active natural products composed of fascinatingly complex structures are often regarded as not amenable to traditional systematic structure-function studies enlisted in medicinal chemistry for the optimization of their properties beyond what might be accomplished by semisynthetic modification. Herein, we summarize our recent studies on the Vinca alkaloids vinblastine and vincristine, often considered as prototypical members of such natural products, that not only inspired the development of powerful new synthetic methodology designed to expedite their total synthesis but have subsequently led to the discovery of several distinct classes of new, more potent, and previously inaccessible analogues. With use of the newly developed methodology and in addition to ongoing efforts to systematically define the importance of each embedded structural feature of vinblastine, two classes of analogues already have been discovered that enhance the potency of the natural products >10-fold. In one instance, remarkable progress has also been made on the refractory problem of reducing Pgp transport responsible for clinical resistance with a series of derivatives made accessible only using the newly developed synthetic methodology. Unlike the removal of vinblastine structural features or substituents, which typically has a detrimental impact, the additions of new structural features have been found that can enhance target tubulin binding affinity and functional activity while simultaneously disrupting Pgp binding, transport, and functional resistance. Already analogues are in hand that are deserving of full preclinical development, and it is a tribute to the advances in organic synthesis that they are readily accessible even on a natural product of a complexity once thought refractory to such an approach. PMID:25586069

  5. Response surface methodology and process optimization of sustained release pellets using Taguchi orthogonal array design and central composite design

    PubMed Central

    Singh, Gurinder; Pai, Roopa S.; Devi, V. Kusum

    2012-01-01

    Furosemide is a powerful diuretic and antihypertensive drug which has low bioavailability due to hepatic first pass metabolism and has a short half-life of 2 hours. To overcome the above drawback, the present study was carried out to formulate and evaluate sustained release (SR) pellets of furosemide for oral administration prepared by extrusion/spheronization. Drug Coat L-100 was used within the pellet core along with microcrystalline cellulose as the diluent and concentration of selected binder was optimized to be 1.2%. The formulation was prepared with drug to polymer ratio 1:3. It was optimized using Design of Experiments by employing a 32 central composite design that was used to systematically optimize the process parameters combined with response surface methodology. Dissolution studies were carried out with USP apparatus Type I (basket type) in both simulated gastric and intestinal pH. The statistical technique, i.e., the two-tailed paired t test and one-way ANOVA of in vitro data has proposed that there was very significant (P≤0.05) difference in dissolution profile of furosemide SR pellets when compared with pure drug and commercial product. Validation of the process optimization study indicated an extremely high degree of prognostic ability. The study effectively undertook the development of optimized process parameters of pelletization of furosemide pellets with tremendous SR characteristics. PMID:22470891

  6. A design methodology for robust failure detection and isolation

    NASA Technical Reports Server (NTRS)

    Pattipati, K. R.; Willsky, A. S.; Deckert, J. C.; Eterno, J. S.; Weiss, J. S.

    1984-01-01

    A decentralized failure detection and isolation (FDI) methodology, which is robust with respect to model uncertainties and noise, is presented Redundancy metrics are developed, and optimization problems are posed for the choices of robust parity relations. Closed-form solutions for some special failure cases are given. Connections are drawn with other disciplines, and the use of the metrics to evaluate alternative FDI schemes is discussed.

  7. A Systematic Review of Methodology: Time Series Regression Analysis for Environmental Factors and Infectious Diseases

    PubMed Central

    Imai, Chisato; Hashizume, Masahiro

    2015-01-01

    Background: Time series analysis is suitable for investigations of relatively direct and short-term effects of exposures on outcomes. In environmental epidemiology studies, this method has been one of the standard approaches to assess impacts of environmental factors on acute non-infectious diseases (e.g. cardiovascular deaths), with conventionally generalized linear or additive models (GLM and GAM). However, the same analysis practices are often observed with infectious diseases despite of the substantial differences from non-infectious diseases that may result in analytical challenges. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, systematic review was conducted to elucidate important issues in assessing the associations between environmental factors and infectious diseases using time series analysis with GLM and GAM. Published studies on the associations between weather factors and malaria, cholera, dengue, and influenza were targeted. Findings: Our review raised issues regarding the estimation of susceptible population and exposure lag times, the adequacy of seasonal adjustments, the presence of strong autocorrelations, and the lack of a smaller observation time unit of outcomes (i.e. daily data). These concerns may be attributable to features specific to infectious diseases, such as transmission among individuals and complicated causal mechanisms. Conclusion: The consequence of not taking adequate measures to address these issues is distortion of the appropriate risk quantifications of exposures factors. Future studies should pay careful attention to details and examine alternative models or methods that improve studies using time series regression analysis for environmental determinants of infectious diseases. PMID:25859149

  8. A systematic review of mosquito coils and passive emanators: defining recommendations for spatial repellency testing methodologies

    PubMed Central

    2012-01-01

    Mosquito coils, vaporizer mats and emanators confer protection against mosquito bites through the spatial action of emanated vapor or airborne pyrethroid particles. These products dominate the pest control market; therefore, it is vital to characterize mosquito responses elicited by the chemical actives and their potential for disease prevention. The aim of this review was to determine effects of mosquito coils and emanators on mosquito responses that reduce human-vector contact and to propose scientific consensus on terminologies and methodologies used for evaluation of product formats that could contain spatial chemical actives, including indoor residual spraying (IRS), long lasting insecticide treated nets (LLINs) and insecticide treated materials (ITMs). PubMed, (National Centre for Biotechnology Information (NCBI), U.S. National Library of Medicine, NIH), MEDLINE, LILAC, Cochrane library, IBECS and Armed Forces Pest Management Board Literature Retrieval System search engines were used to identify studies of pyrethroid based coils and emanators with key-words “Mosquito coils” “Mosquito emanators” and “Spatial repellents”. It was concluded that there is need to improve statistical reporting of studies, and reach consensus in the methodologies and terminologies used through standardized testing guidelines. Despite differing evaluation methodologies, data showed that coils and emanators induce mortality, deterrence, repellency as well as reduce the ability of mosquitoes to feed on humans. Available data on efficacy outdoors, dose–response relationships and effective distance of coils and emanators is inadequate for developing a target product profile (TPP), which will be required for such chemicals before optimized implementation can occur for maximum benefits in disease control. PMID:23216844

  9. A systematic review of mosquito coils and passive emanators: defining recommendations for spatial repellency testing methodologies.

    PubMed

    Ogoma, Sheila B; Moore, Sarah J; Maia, Marta F

    2012-01-01

    Mosquito coils, vaporizer mats and emanators confer protection against mosquito bites through the spatial action of emanated vapor or airborne pyrethroid particles. These products dominate the pest control market; therefore, it is vital to characterize mosquito responses elicited by the chemical actives and their potential for disease prevention. The aim of this review was to determine effects of mosquito coils and emanators on mosquito responses that reduce human-vector contact and to propose scientific consensus on terminologies and methodologies used for evaluation of product formats that could contain spatial chemical actives, including indoor residual spraying (IRS), long lasting insecticide treated nets (LLINs) and insecticide treated materials (ITMs). PubMed, (National Centre for Biotechnology Information (NCBI), U.S. National Library of Medicine, NIH), MEDLINE, LILAC, Cochrane library, IBECS and Armed Forces Pest Management Board Literature Retrieval System search engines were used to identify studies of pyrethroid based coils and emanators with key-words "Mosquito coils" "Mosquito emanators" and "Spatial repellents". It was concluded that there is need to improve statistical reporting of studies, and reach consensus in the methodologies and terminologies used through standardized testing guidelines. Despite differing evaluation methodologies, data showed that coils and emanators induce mortality, deterrence, repellency as well as reduce the ability of mosquitoes to feed on humans. Available data on efficacy outdoors, dose-response relationships and effective distance of coils and emanators is inadequate for developing a target product profile (TPP), which will be required for such chemicals before optimized implementation can occur for maximum benefits in disease control. PMID:23216844

  10. A Design Methodology for Complex (E)-Learning. Innovative Session.

    ERIC Educational Resources Information Center

    Bastiaens, Theo; van Merrienboer, Jeroen; Hoogveld, Bert

    Human resource development (HRD) specialists are searching for instructional design models that accommodate e-learning platforms. Van Merrienboer proposed the four-component instructional design model (4C/ID model) for competency-based education. The model's basic message is that well-designed learning environments can always be described in terms…

  11. Researching experiences of terminal cancer: a systematic review of methodological issues and approaches.

    PubMed

    Harris, F M; Kendall, M; Bentley, A; Maguire, R; Worth, A; Murray, S; Boyd, K; Brown, D; Kearney, N; Sheikh, A

    2008-07-01

    The objectives of this review were to assess the methods and approaches applied to end-of-life cancer research based on papers focusing on approaches or methodological issues related to seeking the views of people affected by terminal cancer. A comprehensive search of 10 databases (January 1980-February 2004) was undertaken. References were screened, quality assessed and data extracted by two reviewers. Analysis followed a meta-narrative approach. Fifteen papers were included. They discussed 'traditional' approaches, such as focus groups, interviews, surveys, as well as innovative approaches allied to the arts. They reveal that mixed methods are gaining popularity. The emotional demands placed on researchers and the ethical issues involved in this research area were also discussed. We concluded that researchers should embrace innovative approaches from other areas of social science, such as the use of arts-based techniques. This may facilitate recruitment of the hard-to-reach groups and engage with experiences that may be otherwise difficult to verbalize. Although researching the needs of the dying carries challenges, these are not the exclusive domain of the cancer field. This study reveals that diverse methods, from research-based drama to postal questionnaires, can enhance end-of-life research. However, this review reveals the need for more methodological work to be undertaken and disseminated. PMID:18485015

  12. Breast cancer statistics and prediction methodology: a systematic review and analysis.

    PubMed

    Dubey, Ashutosh Kumar; Gupta, Umesh; Jain, Sonal

    2015-01-01

    Breast cancer is a menacing cancer, primarily affecting women. Continuous research is going on for detecting breast cancer in the early stage as the possibility of cure in early stages is bright. There are two main objectives of this current study, first establish statistics for breast cancer and second to find methodologies which can be helpful in the early stage detection of the breast cancer based on previous studies. The breast cancer statistics for incidence and mortality of the UK, US, India and Egypt were considered for this study. The finding of this study proved that the overall mortality rates of the UK and US have been improved because of awareness, improved medical technology and screening, but in case of India and Egypt the condition is less positive because of lack of awareness. The methodological findings of this study suggest a combined framework based on data mining and evolutionary algorithms. It provides a strong bridge in improving the classification and detection accuracy of breast cancer data. PMID:26028079

  13. Drift design methodology and preliminary application for the Yucca Mountain Site Characterization Project; Yucca Mountain Site Characterization Project

    SciTech Connect

    Hardy, M.P.; Bauer, S.J.

    1991-12-01

    Excavation stability in an underground nuclear waste repository is required during construction, emplacement, retrieval (if required), and closure phases to ensure worker health and safety, and to prevent development of potential pathways for radionuclide migration in the post-closure period. Stable excavations are developed by appropriate excavation procedures, design of the room shape, design and installation of rock support reinforcement systems, and implementation of appropriate monitoring and maintenance programs. In addition to the loads imposed by the in situ stress field, the repository drifts will be impacted by thermal loads developed after waste emplacement and, periodically, by seismic loads from naturally occurring earthquakes and underground nuclear events. A priori evaluation of stability is required for design of the ground support system, to confirm that the thermal loads are reasonable, and to support the license application process. In this report, a design methodology for assessing drift stability is presented. This is based on site conditions, together with empirical and analytical methods. Analytical numerical methods are emphasized at this time because empirical data are unavailable for excavations in welded tuff either at elevated temperatures or under seismic loads. The analytical methodology incorporates analysis of rock masses that are systematically jointed, randomly jointed, and sparsely jointed. In situ thermal and seismic loads are considered. Methods of evaluating the analytical results and estimating ground support requirements for all the full range of expected ground conditions are outlines. The results of a preliminary application of the methodology using the limited available data are presented. 26 figs., 55 tabs.

  14. A transonic-small-disturbance wing design methodology

    NASA Technical Reports Server (NTRS)

    Phillips, Pamela S.; Waggoner, Edgar G.; Campbell, Richard L.

    1988-01-01

    An automated transonic design code has been developed which modifies an initial airfoil or wing in order to generate a specified pressure distribution. The design method uses an iterative approach that alternates between a potential-flow analysis and a design algorithm that relates changes in surface pressure to changes in geometry. The analysis code solves an extended small-disturbance potential-flow equation and can model a fuselage, pylons, nacelles, and a winglet in addition to the wing. A two-dimensional option is available for airfoil analysis and design. Several two- and three-dimensional test cases illustrate the capabilities of the design code.

  15. 77 FR 9256 - Design and Methodology for Postmarket Surveillance Studies Under Section 522 of the Federal Food...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-16

    ... HUMAN SERVICES Food and Drug Administration Design and Methodology for Postmarket Surveillance Studies... announcing a public workshop entitled ``Design and Methodology for Postmarket Surveillance Studies under... stakeholders with experience in epidemiology, statistics, and biomedical research to advance the design...

  16. A Systematic Methodology for Constructing High-Order Energy Stable WENO Schemes

    NASA Technical Reports Server (NTRS)

    Yamaleev, Nail K.; Carpenter, Mark H.

    2009-01-01

    A third-order Energy Stable Weighted Essentially Non{Oscillatory (ESWENO) finite difference scheme developed by Yamaleev and Carpenter [1] was proven to be stable in the energy norm for both continuous and discontinuous solutions of systems of linear hyperbolic equations. Herein, a systematic approach is presented that enables "energy stable" modifications for existing WENO schemes of any order. The technique is demonstrated by developing a one-parameter family of fifth-order upwind-biased ESWENO schemes; ESWENO schemes up to eighth order are presented in the appendix. New weight functions are also developed that provide (1) formal consistency, (2) much faster convergence for smooth solutions with an arbitrary number of vanishing derivatives, and (3) improved resolution near strong discontinuities.

  17. A Systematic Methodology for Constructing High-Order Energy-Stable WENO Schemes

    NASA Technical Reports Server (NTRS)

    Yamaleev, Nail K.; Carpenter, Mark H.

    2008-01-01

    A third-order Energy Stable Weighted Essentially Non-Oscillatory (ESWENO) finite difference scheme developed by Yamaleev and Carpenter (AIAA 2008-2876, 2008) was proven to be stable in the energy norm for both continuous and discontinuous solutions of systems of linear hyperbolic equations. Herein, a systematic approach is presented that enables \\energy stable" modifications for existing WENO schemes of any order. The technique is demonstrated by developing a one-parameter family of fifth-order upwind-biased ESWENO schemes; ESWENO schemes up to eighth order are presented in the appendix. New weight functions are also developed that provide (1) formal consistency, (2) much faster convergence for smooth solutions with an arbitrary number of vanishing derivatives, and (3) improved resolution near strong discontinuities.

  18. Influence of Glenosphere Design on Outcomes and Complications of Reverse Arthroplasty: A Systematic Review

    PubMed Central

    Lawrence, Cassandra; Williams, Gerald R.

    2016-01-01

    Background Different implant designs are utilized in reverse shoulder arthroplasty. The purpose of this systematic review was to evaluate the results of reverse shoulder arthroplasty using a traditional (Grammont) prosthesis and a lateralized prosthesis for the treatment of cuff tear arthropathy and massive irreparable rotator cuff tears. Methods A systematic review of the literature was performed via a search of two electronic databases. Two reviewers evaluated the quality of methodology and retrieved data from each included study. In cases where the outcomes data were similar between studies, the data were pooled using frequency-weighted mean values to generate summary outcomes. Results Thirteen studies met the inclusion and exclusion criteria. Demographics were similar between treatment groups. The frequency-weighted mean active external rotation was 24° in the traditional group and 46° in the lateralized group (p = 0.0001). Scapular notching was noted in 44.9% of patients in the traditional group compared to 5.4% of patients in the lateralized group (p = 0.0001). The rate of clinically significant glenoid loosening was 1.8% in the traditional group and 8.8% in the lateralized group (p = 0.003). Conclusions Both the traditional Grammont and the lateralized offset reverse arthroplasty designs can improve pain and function in patients with diagnoses of cuff tear arthropathy and irreparable rotator cuff tear. While a lateralized design can result in increased active external rotation and decreased rates of scapular notching, there may be a higher rate of glenoid baseplate loosening. PMID:27583112

  19. Designing and Integrating Purposeful Learning in Game Play: A Systematic Review

    ERIC Educational Resources Information Center

    Ke, Fengfeng

    2016-01-01

    Via a systematic review of the literature on learning games, this article presents a systematic discussion on the design of intrinsic integration of domain-specific learning in game mechanics and game world design. A total of 69 articles ultimately met the inclusion criteria and were coded for the literature synthesis. Exemplary learning games…

  20. Improved FTA methodology and application to subsea pipeline reliability design.

    PubMed

    Lin, Jing; Yuan, Yongbo; Zhang, Mingyuan

    2014-01-01

    An innovative logic tree, Failure Expansion Tree (FET), is proposed in this paper, which improves on traditional Fault Tree Analysis (FTA). It describes a different thinking approach for risk factor identification and reliability risk assessment. By providing a more comprehensive and objective methodology, the rather subjective nature of FTA node discovery is significantly reduced and the resulting mathematical calculations for quantitative analysis are greatly simplified. Applied to the Useful Life phase of a subsea pipeline engineering project, the approach provides a more structured analysis by constructing a tree following the laws of physics and geometry. Resulting improvements are summarized in comparison table form. PMID:24667681

  1. Improved FTA Methodology and Application to Subsea Pipeline Reliability Design

    PubMed Central

    Lin, Jing; Yuan, Yongbo; Zhang, Mingyuan

    2014-01-01

    An innovative logic tree, Failure Expansion Tree (FET), is proposed in this paper, which improves on traditional Fault Tree Analysis (FTA). It describes a different thinking approach for risk factor identification and reliability risk assessment. By providing a more comprehensive and objective methodology, the rather subjective nature of FTA node discovery is significantly reduced and the resulting mathematical calculations for quantitative analysis are greatly simplified. Applied to the Useful Life phase of a subsea pipeline engineering project, the approach provides a more structured analysis by constructing a tree following the laws of physics and geometry. Resulting improvements are summarized in comparison table form. PMID:24667681

  2. A Methodology for Quantifying Certain Design Requirements During the Design Phase

    NASA Technical Reports Server (NTRS)

    Adams, Timothy; Rhodes, Russel

    2005-01-01

    A methodology for developing and balancing quantitative design requirements for safety, reliability, and maintainability has been proposed. Conceived as the basis of a more rational approach to the design of spacecraft, the methodology would also be applicable to the design of automobiles, washing machines, television receivers, or almost any other commercial product. Heretofore, it has been common practice to start by determining the requirements for reliability of elements of a spacecraft or other system to ensure a given design life for the system. Next, safety requirements are determined by assessing the total reliability of the system and adding redundant components and subsystems necessary to attain safety goals. As thus described, common practice leaves the maintainability burden to fall to chance; therefore, there is no control of recurring costs or of the responsiveness of the system. The means that have been used in assessing maintainability have been oriented toward determining the logistical sparing of components so that the components are available when needed. The process established for developing and balancing quantitative requirements for safety (S), reliability (R), and maintainability (M) derives and integrates NASA s top-level safety requirements and the controls needed to obtain program key objectives for safety and recurring cost (see figure). Being quantitative, the process conveniently uses common mathematical models. Even though the process is shown as being worked from the top down, it can also be worked from the bottom up. This process uses three math models: (1) the binomial distribution (greaterthan- or-equal-to case), (2) reliability for a series system, and (3) the Poisson distribution (less-than-or-equal-to case). The zero-fail case for the binomial distribution approximates the commonly known exponential distribution or "constant failure rate" distribution. Either model can be used. The binomial distribution was selected for

  3. Propulsion integration of hypersonic air-breathing vehicles utilizing a top-down design methodology

    NASA Astrophysics Data System (ADS)

    Kirkpatrick, Brad Kenneth

    In recent years, a focus of aerospace engineering design has been the development of advanced design methodologies and frameworks to account for increasingly complex and integrated vehicles. Techniques such as parametric modeling, global vehicle analyses, and interdisciplinary data sharing have been employed in an attempt to improve the design process. The purpose of this study is to introduce a new approach to integrated vehicle design known as the top-down design methodology. In the top-down design methodology, the main idea is to relate design changes on the vehicle system and sub-system level to a set of over-arching performance and customer requirements. Rather than focusing on the performance of an individual system, the system is analyzed in terms of the net effect it has on the overall vehicle and other vehicle systems. This detailed level of analysis can only be accomplished through the use of high fidelity computational tools such as Computational Fluid Dynamics (CFD) or Finite Element Analysis (FEA). The utility of the top-down design methodology is investigated through its application to the conceptual and preliminary design of a long-range hypersonic air-breathing vehicle for a hypothetical next generation hypersonic vehicle (NHRV) program. System-level design is demonstrated through the development of the nozzle section of the propulsion system. From this demonstration of the methodology, conclusions are made about the benefits, drawbacks, and cost of using the methodology.

  4. Probabilistic Design Methodology and its Application to the Design of an Umbilical Retract Mechanism

    NASA Technical Reports Server (NTRS)

    Onyebueke, Landon; Ameye, Olusesan

    2002-01-01

    A lot has been learned from past experience with structural and machine element failures. The understanding of failure modes and the application of an appropriate design analysis method can lead to improved structural and machine element safety as well as serviceability. To apply Probabilistic Design Methodology (PDM), all uncertainties are modeled as random variables with selected distribution types, means, and standard deviations. It is quite difficult to achieve a robust design without considering the randomness of the design parameters which is the case in the use of the Deterministic Design Approach. The US Navy has a fleet of submarine-launched ballistic missiles. An umbilical plug joins the missile to the submarine in order to provide electrical and cooling water connections. As the missile leaves the submarine, an umbilical retract mechanism retracts the umbilical plug clear of the advancing missile after disengagement during launch and retrains the plug in the retracted position. The design of the current retract mechanism in use was based on the deterministic approach which puts emphasis on factor of safety. A new umbilical retract mechanism that is simpler in design, lighter in weight, more reliable, easier to adjust, and more cost effective has become desirable since this will increase the performance and efficiency of the system. This paper reports on a recent project performed at Tennessee State University for the US Navy that involved the application of PDM to the design of an umbilical retract mechanism. This paper demonstrates how the use of PDM lead to the minimization of weight and cost, and the maximization of reliability and performance.

  5. Probabilistic Design Methodology and its Application to the Design of an Umbilical Retract Mechanism

    NASA Astrophysics Data System (ADS)

    Onyebueke, Landon; Ameye, Olusesan

    2002-10-01

    A lot has been learned from past experience with structural and machine element failures. The understanding of failure modes and the application of an appropriate design analysis method can lead to improved structural and machine element safety as well as serviceability. To apply Probabilistic Design Methodology (PDM), all uncertainties are modeled as random variables with selected distribution types, means, and standard deviations. It is quite difficult to achieve a robust design without considering the randomness of the design parameters which is the case in the use of the Deterministic Design Approach. The US Navy has a fleet of submarine-launched ballistic missiles. An umbilical plug joins the missile to the submarine in order to provide electrical and cooling water connections. As the missile leaves the submarine, an umbilical retract mechanism retracts the umbilical plug clear of the advancing missile after disengagement during launch and retrains the plug in the retracted position. The design of the current retract mechanism in use was based on the deterministic approach which puts emphasis on factor of safety. A new umbilical retract mechanism that is simpler in design, lighter in weight, more reliable, easier to adjust, and more cost effective has become desirable since this will increase the performance and efficiency of the system. This paper reports on a recent project performed at Tennessee State University for the US Navy that involved the application of PDM to the design of an umbilical retract mechanism. This paper demonstrates how the use of PDM lead to the minimization of weight and cost, and the maximization of reliability and performance.

  6. Systematic reviews with language restrictions and no author contact have lower overall credibility: a methodology study

    PubMed Central

    Wang, Zhen; Brito, Juan P; Tsapas, Apostolos; Griebeler, Marcio L; Alahdab, Fares; Murad, Mohammad Hassan

    2015-01-01

    Background High-quality systematic reviews (SRs) require rigorous approaches to identify, appraise, select, and synthesize research evidence relevant to a specific question. In this study, we evaluated the association between two steps in the conduct of an SR – restricting the search to English, and author contact for missing data – and the overall credibility of a SR. Methods All SRs cited by the Endocrine Society’s Clinical Practice Guidelines published from October 2006 through January 2012 were included. The main outcome was the overall A Measurement Tool to Assess Systematic Reviews (AMSTAR) score, as a surrogate of SR credibility. Nonparametric Kruskal–Wallis tests and multivariable linear regression models were used to investigate the association between language restriction, author contact for missing data, and the overall AMSTAR score. Results In all, 69 SRs were included in the analysis. Only 31 SRs (45%) reported searching non-English literature, with an average AMSTAR score of 7.90 (standard deviation [SD] =1.64). SRs that reported language restriction received significantly lower AMSTAR scores (mean =5.25, SD =2.32) (P<0.001). Only 30 SRs (43%) reported contacting authors for missing data, and these received, on average, 2.59 more AMSTAR points (SD =1.95) than those who did not (P<0.001). In multivariable analyses, AMSTAR score was significantly correlated with language restriction (beta =−1.31, 95% confidence interval [CI]: −2.62, −0.01, P=0.05) and author contact for missing data (beta =2.16, 95% CI: 0.91, 3.41, P=0.001). However, after adjusting for compliance with reporting guidelines, language restriction was no longer significantly associated with the AMSTAR score. Conclusion Fewer than half of the SRs conducted to support the clinical practice guidelines we examined reported contacting study authors or searched non–English literature. SRs that did not conduct these two steps had lower quality scores, suggesting the importance of

  7. Participant Observation, Anthropology Methodology and Design Anthropology Research Inquiry

    ERIC Educational Resources Information Center

    Gunn, Wendy; Løgstrup, Louise B.

    2014-01-01

    Within the design studio, and across multiple field sites, the authors compare involvement of research tools and materials during collaborative processes of designing. Their aim is to trace temporal dimensions (shifts/ movements) of where and when learning takes place along different sites of practice. They do so by combining participant…

  8. Participatory Pattern Workshops: A Methodology for Open Learning Design Inquiry

    ERIC Educational Resources Information Center

    Mor, Yishay; Warburton, Steven; Winters, Niall

    2012-01-01

    In order to promote pedagogically informed use of technology, educators need to develop an active, inquisitive, design-oriented mindset. Design Patterns have been demonstrated as powerful mediators of theory-praxis conversations yet widespread adoption by the practitioner community remains a challenge. Over several years, the authors and their…

  9. A Methodology for Multi-Criteria Information System Design.

    ERIC Educational Resources Information Center

    Chandler, John S.; DeLutis, Thomas G.

    The complexity of the design problem for modern computer based information systems has increased significantly over its predecessors. The problem presented to the designer is to configure a system which satisfies the user criterion while achieving system resource related performance criteria. The purpose of this paper is to present an evaluation…

  10. LWR design decision methodology: Phase II. Final report

    SciTech Connect

    1981-01-01

    Techniques were identified to augment existing design process at the component and system level in order to optimize cost and safety between alternative system designs. The method was demonstrated using the Surry Low Pressure Injection System (LPIS). Three possible backfit options were analyzed for the Surry LPIS, assessing the safety level of each option and estimating the acquisition and installation costs for each. (DLC)

  11. Flexible design clinical trial methodology in regulatory applications.

    PubMed

    Hung, H M James; Wang, Sue-Jane; O'Neill, Robert

    2011-06-15

    Adaptive designs or flexible designs in a broader sense have increasingly been considered in planning pivotal registration clinical trials. Sample size reassessment design and adaptive selection design are two of such designs that appear in regulatory applications. At the design stage, consideration of sample size reassessment at an interim time of the trial should lead to extensive discussion about how to appropriately size the trial. Additionally, careful attention needs to be paid to the issue of how the size of the trial is impacted by the requirement that the final p-value of the trial meets the specific threshold of a clinically meaningful effect. These issues are not straightforward and will be discussed in this work. In a trial design that allows selection between a pre-specified patient subgroup and the initially planned overall patient population based on the accumulating data, there is an issue of what the 'overall' population means. In addition, it is critically important to know how such selection influences the validity of statistical inferences on the potentially modified overall population. This work presents the biases that may incur under adaptive patient selection designs. PMID:21344470

  12. Systems analysis and design methodologies: practicalities and use in today's information systems development efforts.

    PubMed

    Jerva, M

    2001-05-01

    Historically, systems analysis and design methodologies have been used as a guide in software development. Such methods provide structure to software engineers in their efforts to create quality solutions in the real world of information systems. This article looks at the elements that constitute a systems analysis methodology and examines the historical development of systems analysis in software development. It concludes with observations on the strengths and weaknesses of four methodologies and the state of the art of practice today. PMID:11378979

  13. Systematic Neighborhood Observations at High Spatial Resolution: Methodology and Assessment of Potential Benefits

    PubMed Central

    Leonard, Tammy C. M.; Caughy, Margaret O'Brien; Mays, Judith K.; Murdoch, James C.

    2011-01-01

    There is a growing body of public health research documenting how characteristics of neighborhoods are associated with differences in the health status of residents. However, little is known about how the spatial resolution of neighborhood observational data or community audits affects the identification of neighborhood differences in health. We developed a systematic neighborhood observation instrument for collecting data at very high spatial resolution (we observe each parcel independently) and used it to collect data in a low-income minority neighborhood in Dallas, TX. In addition, we collected data on the health status of individuals residing in this neighborhood. We then assessed the inter-rater reliability of the instrument and compared the costs and benefits of using data at this high spatial resolution. Our instrument provides a reliable and cost-effect method for collecting neighborhood observational data at high spatial resolution, which then allows researchers to explore the impact of varying geographic aggregations. Furthermore, these data facilitate a demonstration of the predictive accuracy of self-reported health status. We find that ordered logit models of health status using observational data at different spatial resolution produce different results. This implies a need to analyze the variation in correlative relationships at different geographic resolutions when there is no solid theoretical rational for choosing a particular resolution. We argue that neighborhood data at high spatial resolution greatly facilitates the evaluation of alternative geographic specifications in studies of neighborhood and health. PMID:21673983

  14. Towards uniform accelerometry analysis: a standardization methodology to minimize measurement bias due to systematic accelerometer wear-time variation.

    PubMed

    Katapally, Tarun R; Muhajarine, Nazeem

    2014-05-01

    Accelerometers are predominantly used to objectively measure the entire range of activity intensities - sedentary behaviour (SED), light physical activity (LPA) and moderate to vigorous physical activity (MVPA). However, studies consistently report results without accounting for systematic accelerometer wear-time variation (within and between participants), jeopardizing the validity of these results. This study describes the development of a standardization methodology to understand and minimize measurement bias due to wear-time variation. Accelerometry is generally conducted over seven consecutive days, with participants' data being commonly considered 'valid' only if wear-time is at least 10 hours/day. However, even within 'valid' data, there could be systematic wear-time variation. To explore this variation, accelerometer data of Smart Cities, Healthy Kids study (www.smartcitieshealthykids.com) were analyzed descriptively and with repeated measures multivariate analysis of variance (MANOVA). Subsequently, a standardization method was developed, where case-specific observed wear-time is controlled to an analyst specified time period. Next, case-specific accelerometer data are interpolated to this controlled wear-time to produce standardized variables. To understand discrepancies owing to wear-time variation, all analyses were conducted pre- and post-standardization. Descriptive analyses revealed systematic wear-time variation, both between and within participants. Pre- and post-standardized descriptive analyses of SED, LPA and MVPA revealed a persistent and often significant trend of wear-time's influence on activity. SED was consistently higher on weekdays before standardization; however, this trend was reversed post-standardization. Even though MVPA was significantly higher on weekdays both pre- and post-standardization, the magnitude of this difference decreased post-standardization. Multivariable analyses with standardized SED, LPA and MVPA as outcome

  15. Systematic review finds major deficiencies in sample size methodology and reporting for stepped-wedge cluster randomised trials

    PubMed Central

    Martin, James; Taljaard, Monica; Girling, Alan; Hemming, Karla

    2016-01-01

    Background Stepped-wedge cluster randomised trials (SW-CRT) are increasingly being used in health policy and services research, but unless they are conducted and reported to the highest methodological standards, they are unlikely to be useful to decision-makers. Sample size calculations for these designs require allowance for clustering, time effects and repeated measures. Methods We carried out a methodological review of SW-CRTs up to October 2014. We assessed adherence to reporting each of the 9 sample size calculation items recommended in the 2012 extension of the CONSORT statement to cluster trials. Results We identified 32 completed trials and 28 independent protocols published between 1987 and 2014. Of these, 45 (75%) reported a sample size calculation, with a median of 5.0 (IQR 2.5–6.0) of the 9 CONSORT items reported. Of those that reported a sample size calculation, the majority, 33 (73%), allowed for clustering, but just 15 (33%) allowed for time effects. There was a small increase in the proportions reporting a sample size calculation (from 64% before to 84% after publication of the CONSORT extension, p=0.07). The type of design (cohort or cross-sectional) was not reported clearly in the majority of studies, but cohort designs seemed to be most prevalent. Sample size calculations in cohort designs were particularly poor with only 3 out of 24 (13%) of these studies allowing for repeated measures. Discussion The quality of reporting of sample size items in stepped-wedge trials is suboptimal. There is an urgent need for dissemination of the appropriate guidelines for reporting and methodological development to match the proliferation of the use of this design in practice. Time effects and repeated measures should be considered in all SW-CRT power calculations, and there should be clarity in reporting trials as cohort or cross-sectional designs. PMID:26846897

  16. Detecting and overcoming systematic bias in high-throughput screening technologies: a comprehensive review of practical issues and methodological solutions.

    PubMed

    Caraus, Iurie; Alsuwailem, Abdulaziz A; Nadon, Robert; Makarenkov, Vladimir

    2015-11-01

    Significant efforts have been made recently to improve data throughput and data quality in screening technologies related to drug design. The modern pharmaceutical industry relies heavily on high-throughput screening (HTS) and high-content screening (HCS) technologies, which include small molecule, complementary DNA (cDNA) and RNA interference (RNAi) types of screening. Data generated by these screening technologies are subject to several environmental and procedural systematic biases, which introduce errors into the hit identification process. We first review systematic biases typical of HTS and HCS screens. We highlight that study design issues and the way in which data are generated are crucial for providing unbiased screening results. Considering various data sets, including the publicly available ChemBank data, we assess the rates of systematic bias in experimental HTS by using plate-specific and assay-specific error detection tests. We describe main data normalization and correction techniques and introduce a general data preprocessing protocol. This protocol can be recommended for academic and industrial researchers involved in the analysis of current or next-generation HTS data. PMID:25750417

  17. eLSE Methodology: A Systematic Approach to the e-Learning Systems Evaluation

    ERIC Educational Resources Information Center

    Lanzilotti, Rosa; Ardito, Carmelo; Costabile, Maria F.; De Angeli, Antonella

    2006-01-01

    Quality of e-learning systems is one of the important topics that the researchers are investigating in the last years. This paper refines the concept of quality of e-learning systems and proposes a new framework, called TICS (Technology, Interaction, Content, Services), which focuses on the most important aspects to be considered when designing or…

  18. A Practical Methodology for the Systematic Development of Multiple Choice Tests.

    ERIC Educational Resources Information Center

    Blumberg, Phyllis; Felner, Joel

    Using Guttman's facet design analysis, four parallel forms of a multiple-choice test were developed. A mapping sentence, logically representing the universe of content of a basic cardiology course, specified the facets of the course and the semantic structural units linking them. The facets were: cognitive processes, disease priority, specific…

  19. Information System Design Methodology Based on PERT/CPM Networking and Optimization Techniques.

    ERIC Educational Resources Information Center

    Bose, Anindya

    The dissertation attempts to demonstrate that the program evaluation and review technique (PERT)/Critical Path Method (CPM) or some modified version thereof can be developed into an information system design methodology. The methodology utilizes PERT/CPM which isolates the basic functional units of a system and sets them in a dynamic time/cost…

  20. Structural Design Methodology Based on Concepts of Uncertainty

    NASA Technical Reports Server (NTRS)

    Lin, K. Y.; Du, Jiaji; Rusk, David

    2000-01-01

    In this report, an approach to damage-tolerant aircraft structural design is proposed based on the concept of an equivalent "Level of Safety" that incorporates past service experience in the design of new structures. The discrete "Level of Safety" for a single inspection event is defined as the compliment of the probability that a single flaw size larger than the critical flaw size for residual strength of the structure exists, and that the flaw will not be detected. The cumulative "Level of Safety" for the entire structure is the product of the discrete "Level of Safety" values for each flaw of each damage type present at each location in the structure. Based on the definition of "Level of Safety", a design procedure was identified and demonstrated on a composite sandwich panel for various damage types, with results showing the sensitivity of the structural sizing parameters to the relative safety of the design. The "Level of Safety" approach has broad potential application to damage-tolerant aircraft structural design with uncertainty.

  1. Impact of Molecular Diagnostics for Tuberculosis on Patient-Important Outcomes: A Systematic Review of Study Methodologies

    PubMed Central

    Schumacher, Samuel G.; Sohn, Hojoon; Qin, Zhi Zhen; Gore, Genevieve; Davis, J. Lucian; Denkinger, Claudia M.; Pai, Madhukar

    2016-01-01

    Background Several reviews on the accuracy of Tuberculosis (TB) Nucleic Acid Amplification Tests (NAATs) have been performed but the evidence on their impact on patient-important outcomes has not been systematically reviewed. Given the recent increase in research evaluating such outcomes and the growing list of TB NAATs that will reach the market over the coming years, there is a need to bring together the existing evidence on impact, rather than accuracy. We aimed to assess the approaches that have been employed to measure the impact of TB NAATs on patient-important outcomes in adults with possible pulmonary TB and/or drug-resistant TB. Methods We first develop a conceptual framework to clarify through which mechanisms the improved technical performance of a novel TB test may lead to improved patient outcomes and outline which designs may be used to measure them. We then systematically review the literature on studies attempting to assess the impact of molecular TB diagnostics on such outcomes and provide a narrative synthesis of designs used, outcomes assessed and risk of bias across different study designs. Results We found 25 eligible studies that assessed a wide range of outcomes and utilized a variety of experimental and observational study designs. Many potentially strong design options have never been used. We found that much of the available evidence on patient-important outcomes comes from a small number of settings with particular epidemiological and operational context and that confounding, time trends and incomplete outcome data receive insufficient attention. Conclusions A broader range of designs should be considered when designing studies to assess the impact of TB diagnostics on patient outcomes and more attention needs to be paid to the analysis as concerns about confounding and selection bias become relevant in addition to those on measurement that are of greatest concern in accuracy studies. PMID:26954678

  2. New methodology for shaft design based on life expectancy

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.

    1986-01-01

    The design of power transmission shafting for reliability has not historically received a great deal of attention. However, weight sensitive aerospace and vehicle applications and those where the penalties of shaft failure are great, require greater confidence in shaft design than earlier methods provided. This report summarizes a fatigue strength-based, design method for sizing shafts under variable amplitude loading histories for limited or nonlimited service life. Moreover, applications factors such as press-fitted collars, shaft size, residual stresses from shot peening or plating, corrosive environments can be readily accommodated into the framework of the analysis. Examples are given which illustrate the use of the method, pointing out the large life penalties due to occasional cyclic overloads.

  3. Structural design methodologies for ceramic-based material systems

    NASA Technical Reports Server (NTRS)

    Duffy, Stephen F.; Chulya, Abhisak; Gyekenyesi, John P.

    1991-01-01

    One of the primary pacing items for realizing the full potential of ceramic-based structural components is the development of new design methods and protocols. The focus here is on low temperature, fast-fracture analysis of monolithic, whisker-toughened, laminated, and woven ceramic composites. A number of design models and criteria are highlighted. Public domain computer algorithms, which aid engineers in predicting the fast-fracture reliability of structural components, are mentioned. Emphasis is not placed on evaluating the models, but instead is focused on the issues relevant to the current state of the art.

  4. New Methods in Design Education: The Systemic Methodology and the Use of Sketch in the Conceptual Design Stage

    ERIC Educational Resources Information Center

    Westermeyer, Juan Carlos Briede; Ortuno, Bernabe Hernandis

    2011-01-01

    This study describes the application of a new product concurrent design methodologies in the context in the education of industrial design. The use of the sketch has been utilized many times as a tool of creative expression especially in the conceptual design stage, in an intuitive way and a little out of the context of the reality needs that the…

  5. A Methodology for the Design of Learning Environments

    ERIC Educational Resources Information Center

    Page, Tom; Thorsteinsson, Gisli

    2009-01-01

    This article presents and discusses some theoretical starting points and design considerations for addressing emotional and aesthetic aspects of virtual learning environments (VLEs) for support of ubiquitous teaching, studying and learning. In this article, we note that a VLE should be viewed upon as an interactive and sensations arousing…

  6. Design Based Research Methodology for Teaching with Technology in English

    ERIC Educational Resources Information Center

    Jetnikoff, Anita

    2015-01-01

    Design based research (DBR) is an appropriate method for small scale educational research projects involving collaboration between teachers, students and researchers. It is particularly useful in collaborative projects where an intervention is implemented and evaluated in a grounded context. The intervention can be technological, or a new program…

  7. Kids in the city study: research design and methodology

    PubMed Central

    2011-01-01

    Background Physical activity is essential for optimal physical and psychological health but substantial declines in children's activity levels have occurred in New Zealand and internationally. Children's independent mobility (i.e., outdoor play and traveling to destinations unsupervised), an integral component of physical activity in childhood, has also declined radically in recent decades. Safety-conscious parenting practices, car reliance and auto-centric urban design have converged to produce children living increasingly sedentary lives. This research investigates how urban neighborhood environments can support or enable or restrict children's independent mobility, thereby influencing physical activity accumulation and participation in daily life. Methods/Design The study is located in six Auckland, New Zealand neighborhoods, diverse in terms of urban design attributes, particularly residential density. Participants comprise 160 children aged 9-11 years and their parents/caregivers. Objective measures (global positioning systems, accelerometers, geographical information systems, observational audits) assessed children's independent mobility and physical activity, neighborhood infrastructure, and streetscape attributes. Parent and child neighborhood perceptions and experiences were assessed using qualitative research methods. Discussion This study is one of the first internationally to examine the association of specific urban design attributes with child independent mobility. Using robust, appropriate, and best practice objective measures, this study provides robust epidemiological information regarding the relationships between the built environment and health outcomes for this population. PMID:21781341

  8. Designing institutions and incentives in hospitals: an organization economics methodology.

    PubMed

    Eid, Florence

    2004-01-01

    Recent seminal developments in organization economics, namely the decision rights approach, offer an opportunity to shed new light on an old question, the design of effective institutions. Drawing on conclusions about how and why firm organizational boundaries change, the decision rights approach is used in this article as an analytical lens to develop a new method for assessing institutional and incentive design in restructured hospitals. The article explains the decision rights approach and shows how the Decision Rights Framework developed from it, is a way of mapping of incentive structures to allow a comparative assessment of institutional design, an understudied area, as most work on hospitals has focused on assessing equity versus efficiency tradeoffs. The new method is illustrated drawing on one example from a case study of an innovative self-corporatized hospital in Lebanon that was at the vanguard of hospital restructuring legislation, adopted for system-wide reforms. A country with a strong private sector tradition, Lebanon was fertile territory for analyzing how high-powered incentive schemes emerge from a public sector setting, in a manner similar to the evolution of a firm in reaction to market forces. Among the findings revealed by the approach is that key to "good" design is the identification of requisite incentives and the matching up of incentives with goals through decision rights allocations. The appropriate organizational form is then a logical result. PMID:15839525

  9. Optimum design criteria for a synchronous reluctance motor with concentrated winding using response surface methodology

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Ho; Park, Seong-June; Jeon, Su-Jin

    2006-04-01

    This paper presents an optimization procedure using response surface methodology (RSM) to determine design parameters for reducing torque ripple. The RSM has been achieved to use the experimental design method in combination with finite element method and well adapted to make analytical model for a complex problem considering a lot of interaction of design variables.

  10. Designing a Methodology for Future Air Travel Scenarios

    NASA Technical Reports Server (NTRS)

    Wuebbles, Donald J.; Baughcum, Steven L.; Gerstle, John H.; Edmonds, Jae; Kinnison, Douglas E.; Krull, Nick; Metwally, Munir; Mortlock, Alan; Prather, Michael J.

    1992-01-01

    -subsonic future fleet. The methodology, procedures, and recommendations for the development of future HSCT and the subsonic fleet scenarios used for this evaluation are discussed.

  11. Advanced design methodologies and novel applications of reflectarray antennas

    NASA Astrophysics Data System (ADS)

    Nayeri, Payam

    Reflectarray antennas combine the numerous advantages of printed antenna arrays and reflector antennas and create a hybrid high-gain antenna with a low-profile, low-mass, and diversified radiation performance. Reflectarrays are now emerging as the new generation of high-gain antennas for long-distance communications. In this dissertation, some advanced concepts demonstrating novel features of reflectarray antennas are presented. • First, various approaches for radiation analysis of reflectarray antennas are described and implemented. Numerical results are then presented for a variety of systems and the advantages, limitations, and accuracy of these approaches are discussed and compared with each other. • A broadband technique by using sub-wavelength elements is proposed and prototypes are fabricated and tested. This technique enables the reflectarray to achieve a significant bandwidth improvement with no additional cost. • Infrared reflectarrays antennas are studied for possible applications in concentrating solar power systems. Material losses, an important design issue at infrared frequencies, are investigated and reflectarrays consisted of dielectric resonant elements are proposed with low-loss features at infrared. • Multi-beam reflectarray antennas are studied and it is demonstrated that by optimizing the phase of the elements, a desirable multi-beam performance can be achieved using a single-feed. Local and global phase-only optimization techniques have been implemented. Two Ka-band quad-beam prototypes with symmetric and asymmetric beams have been fabricated and tested. • Different approaches for beam-scanning with reflectarray antennas are also reviewed and it is shown that for moderately wide angle beam-scanning, utilizing a feed displacement technique is more suitable than an aperture phase tuning approach. A feed displacement beam-scanning design with novel aperture phase distribution is proposed for the reflectarray antenna, and is further

  12. Model-Driven Design: Systematically Building Integrated Blended Learning Experiences

    ERIC Educational Resources Information Center

    Laster, Stephen

    2010-01-01

    Developing and delivering curricula that are integrated and that use blended learning techniques requires a highly orchestrated design. While institutions have demonstrated the ability to design complex curricula on an ad-hoc basis, these projects are generally successful at a great human and capital cost. Model-driven design provides a…

  13. Software Design Methodology Migration for a Distributed Ground System

    NASA Technical Reports Server (NTRS)

    Ritter, George; McNair, Ann R. (Technical Monitor)

    2002-01-01

    The Marshall Space Flight Center's (MSFC) Payload Operations Center (POC) ground system has been developed and has evolved over a period of about 10 years. During this time the software processes have migrated from more traditional to more contemporary development processes. The new Software processes still emphasize requirements capture, software configuration management, design documenting, and making sure the products that have been developed are accountable to initial requirements. This paper will give an overview of how the Software Process have evolved highlighting the positives as well as the negatives. In addition, we will mention the COTS tools that have been integrated into the processes and how the COTS have provided value to the project .

  14. Development of a combustor analytical design methodology for liquid rocket engines

    NASA Technical Reports Server (NTRS)

    Pieper, Jerry L.; Muss, Jeff

    1989-01-01

    The development of a user friendly computerized methodology for the design and analysis of liquid propellant rocket engine combustion chambers is described. An overview of the methodology, consisting of a computer program containing an appropriate modular assembly of existing industry wide performance and combustion stability models, is presented. These models are linked with an interactive front end processor enabling the user to define the performance and stability traits of an existing design (point analysis) or to create the essential design features of a combustor to meet specific performance goals and combustion stability (point design). Plans for demonstration and verification of this methodology are also presented. These plans include the creation of combustor designs using the methodology, together with predictions of the performance and combustion stability for each design. A verification test program of 26 hot fire tests with up to four designs created using this methodology is described. This testing is planned using LOX/RP-1 propellants with a thrust level of approx. 220,000 N (50,000 lbf).

  15. Theories and Research Methodologies for Design-Based Implementation Research: Examples from Four Cases

    ERIC Educational Resources Information Center

    Russell, Jennifer Lin; Jackson, Kara; Krumm, Andrew E.; Frank, Kenneth A.

    2013-01-01

    Design-Based Implementation Research is the process of engaging "learning scientists, policy researchers, and practitioners in a model of collaborative, iterative, and systematic research and development" designed to address persistent problems of teaching and learning. Addressing persistent problems of teaching and learning requires…

  16. Reporting of planned statistical methods in published surgical randomised trial protocols: a protocol for a methodological systematic review

    PubMed Central

    Madden, Kim; Arseneau, Erika; Evaniew, Nathan; Smith, Christopher S; Thabane, Lehana

    2016-01-01

    Introduction Poor reporting can lead to inadequate presentation of data, confusion regarding research methodology used, selective reporting of results, and other misinformation regarding health research. One of the most recent attempts to improve quality of reporting comes from the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) Group, which makes recommendations for the reporting of protocols. In this report, we present a protocol for a systematic review of published surgical randomised controlled trial (RCT) protocols, with the purpose of assessing the reporting quality and completeness of the statistical aspects. Methods We will include all published protocols of randomised trials that investigate surgical interventions. We will search MEDLINE, EMBASE, and CENTRAL for relevant studies. Author pairs will independently review all titles, abstracts, and full texts identified by the literature search, and extract data using a structured data extraction form. We will extract the following: year of publication, country, sample size, description of study population, description of intervention and control, primary outcome, important methodological qualities, and quality of reporting of planned statistical methods based on the SPIRIT guidelines. Ethics and dissemination The results of this review will demonstrate the quality of statistical reporting of published surgical RCT protocols. This knowledge will inform recommendations to surgeons, researchers, journal editors and peer reviewers, and other knowledge users that focus on common deficiencies in reporting and how to rectify them. Ethics approval for this study is not required. We will disseminate the results of this review in peer-reviewed publications and conference presentations, and at a doctoral independent study of oral defence. PMID:27259528

  17. Prescribed wake methodologies for wind turbine design codes

    SciTech Connect

    Galbraith, R.A.M.; Coton, F.N.; Robison, D.J.

    1995-12-31

    Prescribed wake performance assessment models have been developed successfully for both vertical (VAWT) and horizontal (HAWT) axis wind turbines. In the case of the VAWT model the Beddoes and Leishman dynamic stall model has been incorporated. This has resulted in a fully unsteady 3-D code, establishing extremely accurate performance prediction across a wide range of operating conditions. Comparison of performance estimates from the prescribed wake model with those from free wake models have shown excellent correlation. To date, the HAWT model has been developed for the consideration of steady axial and yawed inflows. In the axial flow case comparisons of predicted power output with field data and free wake predictions have shown excellent agreement. Full validation of the yawed flow model is currently underway, with very encouraging initial results. The capabilities of the HAWT model are currently being extended by the inclusion of the Beddoes and Leishman dynamic stall model. Consideration of the significant unsteady aerodynamic influences acting on HAWTs while operating in yaw will significantly improve the models performance. The power of this modelling technique is the significant reduction in the computational overhead it offers. The prescribed wake models offer performance estimates of comparable detail and accuracy to those from free vortex analyses in minutes rather than hours. As such these models are highly suited to design assessment, with particular application to fatigue load analysis.

  18. Weibull-Based Design Methodology for Rotating Aircraft Engine Structures

    NASA Technical Reports Server (NTRS)

    Zaretsky, Erwin; Hendricks, Robert C.; Soditus, Sherry

    2002-01-01

    The NASA Energy Efficient Engine (E(sup 3)-Engine) is used as the basis of a Weibull-based life and reliability analysis. Each component's life and thus the engine's life is defined by high-cycle fatigue (HCF) or low-cycle fatigue (LCF). Knowing the cumulative life distribution of each of the components making up the engine as represented by a Weibull slope is a prerequisite to predicting the life and reliability of the entire engine. As the engine Weibull slope increases, the predicted lives decrease. The predicted engine lives L(sub 5) (95 % probability of survival) of approximately 17,000 and 32,000 hr do correlate with current engine maintenance practices without and with refurbishment. respectively. The individual high pressure turbine (HPT) blade lives necessary to obtain a blade system life L(sub 0.1) (99.9 % probability of survival) of 9000 hr for Weibull slopes of 3, 6 and 9, are 47,391 and 20,652 and 15,658 hr, respectively. For a design life of the HPT disks having probable points of failure equal to or greater than 36,000 hr at a probability of survival of 99.9 %, the predicted disk system life L(sub 0.1) can vary from 9,408 to 24,911 hr.

  19. A design methodology for evolutionary air transportation networks

    NASA Astrophysics Data System (ADS)

    Yang, Eunsuk

    The air transportation demand at large hubs in the U.S. is anticipated to double in the near future. Current runway construction plans at selected airports can relieve some capacity and delay problems, but many are doubtful that this solution is sufficient to accommodate the anticipated demand growth in the National Airspace System (NAS). With the worsening congestion problem, it is imperative to seek alternative solutions other than costly runway constructions. In this respect, many researchers and organizations have been building models and performing analyses of the NAS. However, the complexity and size of the problem results in an overwhelming task for transportation system modelers. This research seeks to compose an active design algorithm for an evolutionary airline network model so as to include network specific control properties. An airline network designer, referred to as a network architect, can use this tool to assess the possibilities of gaining more capacity by changing the network configuration. Since the Airline Deregulation Act of 1978, the airline service network has evolved into a distinct Hub-and-Spoke (H&S) network. Enplanement demand on the H&S network is the sum of Origin-Destination (O-D) demand and transfer demand. Even though the flight or enplanement demand is a function of O-D demand and passenger routings on the airline network, the distinction between enplanement and O-D demand is not often made. Instead, many demand forecast practices in current days are based on scale-ups from the enplanements, which include the demand to and from transferring network hubs. Based on this research, it was found that the current demand prediction practice can be improved by dissecting enplanements further into smaller pieces of information. As a result, enplanement demand is decomposed into intrinsic and variable parts. The proposed intrinsic demand model is based on the concept of 'true' O-D demand which includes the direction of each round trip

  20. Design-Based Research: Is This a Suitable Methodology for Short-Term Projects?

    ERIC Educational Resources Information Center

    Pool, Jessica; Laubscher, Dorothy

    2016-01-01

    This article reports on a design-based methodology of a thesis in which a fully face-to-face contact module was converted into a blended learning course. The purpose of the article is to report on how design-based phases, in the form of micro-, meso- and macro-cycles were applied to improve practice and to generate design principles. Design-based…

  1. Applied design methodology for lunar rover elastic wheel

    NASA Astrophysics Data System (ADS)

    Cardile, Diego; Viola, Nicole; Chiesa, Sergio; Rougier, Alessandro

    2012-12-01

    In recent years an increasing interest in the Moon surface operations has been experienced. In the future robotic and manned missions of Moon surface exploration will be fundamental in order to lay the groundwork for more ambitious space exploration programs. Surface mobility systems will be the key elements to ensure an efficient and safe Moon exploration. Future lunar rovers are likely to be heavier and able to travel longer distances than the previously developed Moon rover systems. The Lunar Roving Vehicle (LRV) is the only manned rover, which has so far been launched and used on the Moon surface. Its mobility system included flexible wheels that cannot be scaled to the heavier and longer range vehicles. Thus the previously developed wheels are likely not to be suitable for the new larger vehicles. Taking all these considerations into account, on the basis of the system requirements and assumptions, several wheel concepts have been discussed and evaluated through a trade-off analysis. Semi-empirical equations have been utilized to predict the wheel geometrical characteristics, as well as to estimate the motion resistances and the ability of the system to generate thrust. A numerical model has also been implemented, in order to define more into the details the whole wheel design, in terms of wheel geometry and physical properties. As a result of the trade-off analysis, the ellipse wheel concept has shown the best behavior in terms of stiffness, mass budget and dynamic performance. The results presented in the paper have been obtained in cooperation with Thales Alenia Space-Italy and Sicme motori, in the framework of a regional program called STEPS . STEPS-Sistemi e Tecnologie per l'EsPlorazione Spaziale is a research project co-financed by Piedmont Region and firms and universities of the Piedmont Aerospace District in the ambit of the P.O.R-F.E.S.R. 2007-2013 program.

  2. Advanced piloted aircraft flight control system design methodology. Volume 2: The FCX flight control design expert system

    NASA Technical Reports Server (NTRS)

    Myers, Thomas T.; Mcruer, Duane T.

    1988-01-01

    The development of a comprehensive and electric methodology for conceptual and preliminary design of flight control systems is presented and illustrated. The methodology is focused on the design states starting with the layout of system requirements and ending when some viable competing system architectures (feedback control structures) are defined. The approach is centered on the human pilot and the aircraft as both the sources of, and the keys to the solution of, many flight control problems. The methodology relies heavily on computational procedures which are highly interactive with the design engineer. To maximize effectiveness, these techniques, as selected and modified to be used together in the methodology, form a cadre of computational tools specifically tailored for integrated flight control system preliminary design purposes. The FCX expert system as presently developed is only a limited prototype capable of supporting basic lateral-directional FCS design activities related to the design example used. FCX presently supports design of only one FCS architecture (yaw damper plus roll damper) and the rules are largely focused on Class IV (highly maneuverable) aircraft. Despite this limited scope, the major elements which appear necessary for application of knowledge-based software concepts to flight control design were assembled and thus FCX represents a prototype which can be tested, critiqued and evolved in an ongoing process of development.

  3. Experimental design in caecilian systematics: phylogenetic information of mitochondrial genomes and nuclear rag1.

    PubMed

    San Mauro, Diego; Gower, David J; Massingham, Tim; Wilkinson, Mark; Zardoya, Rafael; Cotton, James A

    2009-08-01

    In molecular phylogenetic studies, a major aspect of experimental design concerns the choice of markers and taxa. Although previous studies have investigated the phylogenetic performance of different genes and the effectiveness of increasing taxon sampling, their conclusions are partly contradictory, probably because they are highly context specific and dependent on the group of organisms used in each study. Goldman introduced a method for experimental design in phylogenetics based on the expected information to be gained that has barely been used in practice. Here we use this method to explore the phylogenetic utility of mitochondrial (mt) genes, mt genomes, and nuclear rag1 for studies of the systematics of caecilian amphibians, as well as the effect of taxon addition on the stabilization of a controversial branch of the tree. Overall phylogenetic information estimates per gene, specific estimates per branch of the tree, estimates for combined (mitogenomic) data sets, and estimates as a hypothetical new taxon is added to different parts of the caecilian tree are calculated and compared. In general, the most informative data sets are those for mt transfer and ribosomal RNA genes. Our results also show at which positions in the caecilian tree the addition of taxa have the greatest potential to increase phylogenetic information with respect to the controversial relationships of Scolecomorphus, Boulengerula, and all other teresomatan caecilians. These positions are, as intuitively expected, mostly (but not all) adjacent to the controversial branch. Generating whole mitogenomic and rag1 data for additional taxa joining the Scolecomorphus branch may be a more efficient strategy than sequencing a similar amount of additional nucleotides spread across the current caecilian taxon sampling. The methodology employed in this study allows an a priori evaluation and testable predictions of the appropriateness of particular experimental designs to solve specific questions at

  4. Conjecture Mapping: An Approach to Systematic Educational Design Research

    ERIC Educational Resources Information Center

    Sandoval, William

    2014-01-01

    Design research is strongly associated with the learning sciences community, and in the 2 decades since its conception it has become broadly accepted. Yet within and without the learning sciences there remains confusion about how to do design research, with most scholarship on the approach describing what it is rather than how to do it. This…

  5. Designing Needs Statements in a Systematic Iterative Way

    ERIC Educational Resources Information Center

    Verstegen, D. M. L.; Barnard, Y. F.; Pilot, A.

    2009-01-01

    Designing specifications for technically advanced instructional products, such as e-learning, simulations or simulators requires different kinds of expertise. The SLIM method proposes to involve all stakeholders from the beginning in a series of workshops under the guidance of experienced instructional designers. These instructional designers…

  6. Analysis and Design of Fuselage Structures Including Residual Strength Prediction Methodology

    NASA Technical Reports Server (NTRS)

    Knight, Norman F.

    1998-01-01

    The goal of this research project is to develop and assess methodologies for the design and analysis of fuselage structures accounting for residual strength. Two primary objectives are included in this research activity: development of structural analysis methodology for predicting residual strength of fuselage shell-type structures; and the development of accurate, efficient analysis, design and optimization tool for fuselage shell structures. Assessment of these tools for robustness, efficient, and usage in a fuselage shell design environment will be integrated with these two primary research objectives.

  7. The inclusion of ergonomic tools in the informational, conceptual and preliminary phases of the product design methodology.

    PubMed

    Medeiros, Ivan Luiz de; Batiz, Eduardo Concepción

    2012-01-01

    The process of product development has received special attention as it is being recognized as a source of competitive gain. Through its systematic use companies reduce costs, increase quality and decrease development time. However, one can find products being launched on the market that cause dissatisfaction to its users, and in consequence if the customer feels harmed or injured he will no longer purchase a product from the same brand. This in regard only to the commercial aspect; usually the danger of an accident or injury is not even thought about. This paper is the basis of the dissertation master's degree and used a literature research to build the repertoire, analyzing the methodologies applied by product design engineers, designers and ergonomists. The analysis results demonstrate the inefficiency of the design methodologies ergonomic issues. The contribution of this work lies in the suggestion to include ergonomic tools in all phases of product development and the presentation of a table with the tools that points out its most suitable time of application and results. PMID:22316854

  8. Design methodology for high-speed video processing system based on signal integrity analysis

    NASA Astrophysics Data System (ADS)

    Wang, Rui; Zhang, Hao

    2009-07-01

    On account of high performance requirement of video processing systems and the shortcoming of conventional circuit design method, a design methodology based on the signal integrity (SI) theory for the high-speed video processing system with TI's digital signal processor TMS320DM642 was proposed. The PCB stack-up and construction of the system as well as transmission line characteristic impedance are set and calculated firstly with the impedance control tool Si8000 through this methodology. And then some crucial signals such as data lines of SDRAM are simulated and analyzed with the IBIS models so that reasonable layout and routing rules are established. Finally the system's highdensity PCB design is completed on Cadence SPB15.7 platform. The design result shows that this methodology can effectively restrain signal reflection, crosstalk, rail collapse noise and electromagnetic interference (EMI). Thus it significantly improves stability of the system and shortens development cycles.

  9. Designing Trend-Monitoring Sounds for Helicopters: Methodological Issues and an Application

    ERIC Educational Resources Information Center

    Edworthy, Judy; Hellier, Elizabeth; Aldrich, Kirsteen; Loxley, Sarah

    2004-01-01

    This article explores methodological issues in sonification and sound design arising from the design of helicopter monitoring sounds. Six monitoring sounds (each with 5 levels) were tested for similarity and meaning with 3 different techniques: hierarchical cluster analysis, linkage analysis, and multidimensional scaling. In Experiment 1,…

  10. NATIONAL RESEARCH PROGRAM ON DESIGN-BASED/MODEL-ASSISTED SURVEY METHODOLOGY FOR AQUATIC RESOURCES

    EPA Science Inventory

    We expect to accomplish five major goals with the Program. The first is to extend design-based statistical methodology to cover the unique circumstances encountered in EMAP. The second is to make both existing and newly-developed model-assisted design-based statistical tools m...