Unwin, Stephen D.; Sadovsky, Artyom; Sullivan, E. C.; Anderson, Richard M.
2011-09-30
This white paper accompanies a demonstration model that implements methods for the risk-informed design of monitoring, verification and accounting (RI-MVA) systems in geologic carbon sequestration projects. The intent is that this model will ultimately be integrated with, or interfaced with, the National Risk Assessment Partnership (NRAP) integrated assessment model (IAM). The RI-MVA methods described here apply optimization techniques in the analytical environment of NRAP risk profiles to allow systematic identification and comparison of the risk and cost attributes of MVA design options.
An Example of Risk Informed Design
NASA Technical Reports Server (NTRS)
Banke, Rick; Grant, Warren; Wilson, Paul
2014-01-01
NASA Engineering requested a Probabilistic Risk Assessment (PRA) to compare the difference in the risk of Loss of Crew (LOC) and Loss of Mission (LOM) between different designs of a fluid assembly. They were concerned that the configuration favored by the design team was more susceptible to leakage than a second proposed design, but realized that a quantitative analysis to compare the risks between the two designs might strengthen their argument. The analysis showed that while the second design did help improve the probability of LOC, it did not help from a probability of LOM perspective. This drove the analysis team to propose a minor design change that would drive the probability of LOM down considerably. The analysis also demonstrated that there was another major risk driver that was not immediately obvious from a typical engineering study of the design and was therefore unexpected. None of the proposed alternatives were addressing this risk. This type of trade study demonstrates the importance of performing a PRA in order to completely understand a system's design. It allows managers to use risk as another one of the commodities (e.g., mass, cost, schedule, fault tolerance) that can be traded early in the design of a new system.
Risk Informed Design as Part of the Systems Engineering Process
NASA Technical Reports Server (NTRS)
Deckert, George
2010-01-01
This slide presentation reviews the importance of Risk Informed Design (RID) as an important feature of the systems engineering process. RID is based on the principle that risk is a design commodity such as mass, volume, cost or power. It also reviews Probabilistic Risk Assessment (PRA) as it is used in the product life cycle in the development of NASA's Constellation Program.
Ritterbusch, Stanley; Golay, Michael; Duran, Felicia; Galyean, William; Gupta, Abhinav; Dimitrijevic, Vesna; Malsch, Marty
2003-01-29
OAK B188 Summary of methods proposed for risk informing the design and regulation of future nuclear power plants. All elements of the historical design and regulation process are preserved, but the methods proposed for new plants use probabilistic risk assessment methods as the primary decision making tool.
Impact of NDE reliability developments on risk-informed methods
Walker, S.M.; Ammirato, F.V.
1996-12-01
Risk informed inspection procedures are being developed to more effectively and economically manage degradation in plant piping systems. A key element of this process is applying nondestructive examination (NDE) procedures capable of detecting specific damage mechanisms that may be operative in particular locations. Thus, the needs of risk informed analysis are closely coupled with a firm understanding of the capability of NDE.
Risk Informed Design and Analysis Criteria for Nuclear Structures
Salmon, Michael W.
2015-06-17
Target performance can be achieved by defining design basis ground motion from results of a probabilistic seismic hazards assessment, and introducing known levels of conservatism in the design above the DBE. ASCE 4, 43, DOE-STD-1020 defined the DBE at 4x10-4 and introduce only slight levels of conservatism in response. ASCE 4, 43, DOE-STD-1020 assume code capacities shoot for about 98% NEP. There is a need to have a uniform target (98% NEP) for code developers (ACI, AISC, etc.) to aim for. In considering strengthening options, one must also consider cost/risk reduction achieved.
Risk-Informed Safety Margin Characterization Methods Development Work
Smith, Curtis L; Ma, Zhegang; Tom Riley; Mandelli, Diego; Nielsen, Joseph W; Alfonsi, Andrea; Rabiti, Cristian
2014-09-01
This report summarizes the research activity developed during the Fiscal year 2014 within the Risk Informed Safety Margin and Characterization (RISMC) pathway within the Light Water Reactor Sustainability (LWRS) campaign. This research activity is complementary to the one presented in the INL/EXT-??? report which shows advances Probabilistic Risk Assessment Analysis using RAVEN and RELAP-7 in conjunction to novel flooding simulation tools. Here we present several analyses that prove the values of the RISMC approach in order to assess risk associated to nuclear power plants (NPPs). We focus on simulation based PRA which, in contrast to classical PRA, heavily employs system simulator codes. Firstly we compare, these two types of analyses, classical and RISMC, for a Boiling water reactor (BWR) station black out (SBO) initiating event. Secondly we present an extended BWR SBO analysis using RAVEN and RELAP-5 which address the comments and suggestions received about he original analysis presented in INL/EXT-???. This time we focus more on the stochastic analysis such probability of core damage and on the determination of the most risk-relevant factors. We also show some preliminary results regarding the comparison between RELAP5-3D and the new code RELAP-7 for a simplified Pressurized Water Reactors system. Lastly we present some conceptual ideas regarding the possibility to extended the RISMC capabilities from an off-line tool (i.e., as PRA analysis tool) to an online-tool. In this new configuration, RISMC capabilities can be used to assist and inform reactor operator during real accident scenarios.
2000-08-01
OAK B188 Risk-informed assessment of regulatory and design requirements for future nuclear power plants. Annual report. The overall goal of this research project is to support innovation in new nuclear power plant designs. This project is examining the implications, for future reactors and future safety regulation, of utilizing a new risk-informed regulatory system as a replacement for the current system. This innovation will be made possible through development of a scientific, highly risk-formed approach for the design and regulation of nuclear power plants. This approach will include the development and/or confirmation of corresponding regulatory requirements and industry standards. The major impediment to long term competitiveness of new nuclear plants in the U.S. is the capital cost component--which may need to be reduced on the order of 35% to 40% for Advanced Light Water Reactors (ALWRS) such as System 80+ and Advanced Boiling Water Reactor (ABWR). The required cost reduction for an ALWR such as AP600 or AP1000 would be expected to be less. Such reductions in capital cost will require a fundamental reevaluation of the industry standards and regulatory bases under which nuclear plants are designed and licensed. Fortunately, there is now an increasing awareness that many of the existing regulatory requirements and industry standards are not significantly contributing to safety and reliability and, therefore, are unnecessarily adding to nuclear plant costs. Not only does this degrade the economic competitiveness of nuclear energy, it results in unnecessary costs to the American electricity consumer. While addressing these concerns, this research project will be coordinated with current efforts of industry and NRC to develop risk-informed, performance-based regulations that affect the operation of the existing nuclear plants; however, this project will go further by focusing on the design of new plants.
Curtis Smith; Diego Mandelli
2013-03-01
Safety is central to the design, licensing, operation, and economics of nuclear power plants (NPPs). As the current light water reactor (LWR) NPPs age beyond 60 years, there are possibilities for increased frequency of systems, structures, and components (SSC) degradations or failures that initiate safety significant events, reduce existing accident mitigation capabilities, or create new failure modes. Plant designers commonly “over-design” portions of NPPs and provide robustness in the form of redundant and diverse engineered safety features to ensure that, even in the case of well-beyond design basis scenarios, public health and safety will be protected with a very high degree of assurance. This form of defense-in-depth is a reasoned response to uncertainties and is often referred to generically as “safety margin.” Historically, specific safety margin provisions have been formulated primarily based on engineering judgment backed by a set of conservative engineering calculations. The ability to better characterize and quantify safety margin is important to improved decision making about LWR design, operation, and plant life extension. A systematic approach to characterization of safety margins and the subsequent margin management options represents a vital input to the licensee and regulatory analysis and decision making that will be involved. In addition, as research and development (R&D) in the LWR Sustainability (LWRS) Program and other collaborative efforts yield new data, sensors, and improved scientific understanding of physical processes that govern the aging and degradation of plant SSCs needs and opportunities to better optimize plant safety and performance will become known. To support decision making related to economics, readability, and safety, the RISMC Pathway provides methods and tools that enable mitigation options known as margins management strategies. The purpose of the RISMC Pathway R&D is to support plant decisions for risk-informed
Application of damage mechanism-specific NDE methods in support of risk-informed inspections
Walker, S.M.; Ammirato, F.V.
1996-12-01
Risk-informed inservice inspection (RISI) programs effectively concentrate limited and costly examination resources on systems and locations most relevant to plant safety. The thought process used in the selection of nondestructive evaluation (NDE) methods and procedures in a RISI program is expected to change toward integrating NDE into integrity management, with a concentration on understanding failure mechanisms. Identifying which damage mechanisms may be operative in specific locations and applying appropriate NDE methods to detect the presence of these damage mechanisms is fundamental to effective RISI application. Considerable information is already available on inspection for damage mechanisms such as intergranular stress corrosion cracking (IGSCC), thermal fatigue, and erosion-corrosion. Similar procedures are under development for other damage mechanisms that may occur individually or in combination with other mechanisms. Guidance is provided on application of NDE procedures in an RISI framework to facilitate implementation by utility staff (Gosselin, 1996).
Ritterbusch, S.E.
2000-08-01
The overall goal of this research project is to support innovation in new nuclear power plant designs. This project is examining the implications, for future reactors and future safety regulation, of utilizing a new risk-informed regulatory system as a replacement for the current system. This innovation will be made possible through development of a scientific, highly risk-informed approach for the design and regulation of nuclear power plants. This approach will include the development and.lor confirmation of corresponding regulatory requirements and industry standards. The major impediment to long term competitiveness of new nuclear plants in the U.S. is the capital cost component--which may need to be reduced on the order of 35% to 40% for Advanced Light Water Reactors (ALWRs) such as System 80+ and Advanced Boiling Water Reactor (ABWR). The required cost reduction for an ALWR such as AP600 or AP1000 would be expected to be less. Such reductions in capital cost will require a fundamental reevaluation of the industry standards and regulatory bases under which nuclear plants are designed and licensed. Fortunately, there is now an increasing awareness that many of the existing regulatory requirements and industry standards are not significantly contributing to safety and reliability and, therefore, are unnecessarily adding to nuclear plant costs. Not only does this degrade the economic competitiveness of nuclear energy, it results in unnecessary costs to the American electricity consumer. While addressing these concerns, this research project will be coordinated with current efforts of industry and NRC to develop risk-informed, performance-based regulations that affect the operation of the existing nuclear plants; however, this project will go farther by focusing on the design of new plants.
A Design Heritage-Based Forecasting Methodology for Risk Informed Management of Advanced Systems
NASA Technical Reports Server (NTRS)
Maggio, Gaspare; Fragola, Joseph R.
1999-01-01
The development of next generation systems often carries with it the promise of improved performance, greater reliability, and reduced operational costs. These expectations arise from the use of novel designs, new materials, advanced integration and production technologies intended for functionality replacing the previous generation. However, the novelty of these nascent technologies is accompanied by lack of operational experience and, in many cases, no actual testing as well. Therefore some of the enthusiasm surrounding most new technologies may be due to inflated aspirations from lack of knowledge rather than actual future expectations. This paper proposes a design heritage approach for improved reliability forecasting of advanced system components. The basis of the design heritage approach is to relate advanced system components to similar designs currently in operation. The demonstrated performance of these components could then be used to forecast the expected performance and reliability of comparable advanced technology components. In this approach the greater the divergence of the advanced component designs from the current systems the higher the uncertainty that accompanies the associated failure estimates. Designers of advanced systems are faced with many difficult decisions. One of the most common and more difficult types of these decisions are those related to the choice between design alternatives. In the past decision-makers have found these decisions to be extremely difficult to make because they often involve the trade-off between a known performing fielded design and a promising paper design. When it comes to expected reliability performance the paper design always looks better because it is on paper and it addresses all the know failure modes of the fielded design. On the other hand there is a long, and sometimes very difficult road, between the promise of a paper design and its fulfillment; with the possibility that sometimes the reliability
Cyber-Informed Engineering: The Need for a New Risk Informed and Design Methodology
Price, Joseph Daniel; Anderson, Robert Stephen
2015-06-01
Current engineering and risk management methodologies do not contain the foundational assumptions required to address the intelligent adversary’s capabilities in malevolent cyber attacks. Current methodologies focus on equipment failures or human error as initiating events for a hazard, while cyber attacks use the functionality of a trusted system to perform operations outside of the intended design and without the operator’s knowledge. These threats can by-pass or manipulate traditionally engineered safety barriers and present false information, invalidating the fundamental basis of a safety analysis. Cyber threats must be fundamentally analyzed from a completely new perspective where neither equipment nor human operation can be fully trusted. A new risk analysis and design methodology needs to be developed to address this rapidly evolving threatscape.
NASA Astrophysics Data System (ADS)
Nowak, W.; Enzenhoefer, R.; Bunk, T.
2013-12-01
Wellhead protection zones are commonly delineated via advective travel time analysis without considering any aspects of model uncertainty. In the past decade, research efforts produced quantifiable risk-based safety margins for protection zones. They are based on well vulnerability criteria (e.g., travel times, exposure times, peak concentrations) cast into a probabilistic setting, i.e., they consider model and parameter uncertainty. Practitioners still refrain from applying these new techniques for mainly three reasons. (1) They fear the possibly cost-intensive additional areal demand of probabilistic safety margins, (2) probabilistic approaches are allegedly complex, not readily available, and consume huge computing resources, and (3) uncertainty bounds are fuzzy, whereas final decisions are binary. The primary goal of this study is to show that these reservations are unjustified. We present a straightforward and computationally affordable framework based on a novel combination of well-known tools (e.g., MODFLOW, PEST, Monte Carlo). This framework provides risk-informed decision support for robust and transparent wellhead delineation under uncertainty. Thus, probabilistic risk-informed wellhead protection is possible with methods readily available for practitioners. As vivid proof of concept, we illustrate our key points on a pumped karstic well catchment, located in Germany. In the case study, we show that reliability levels can be increased by re-allocating the existing delineated area at no increase in delineated area. This is achieved by simply swapping delineated low-risk areas against previously non-delineated high-risk areas. Also, we show that further improvements may often be available at only low additional delineation area. Depending on the context, increases or reductions of delineated area directly translate to costs and benefits, if the land is priced, or if land owners need to be compensated for land use restrictions.
Vo, T.V.; Phan, H.K.; Gore, B.F.; Simonen, F.A.; Doctor, S.R.
1997-02-01
As part of the Nondestructive Evaluation Reliability Program sponsored by the US Nuclear Regulatory Commission, the Pacific Northwest National Laboratory has developed risk-informed approaches for inservice inspection plans of nuclear power plants. This method uses probabilistic risk assessment (PRA) results to identify and prioritize the most risk-important components for inspection. The Surry Nuclear Power Station Unit 1 was selected for pilot application of this methodology. This report, which incorporates more recent plant-specific information and improved risk-informed methodology and tools, is Revision 1 of the earlier report (NUREG/CR-6181). The methodology discussed in the original report is no longer current and a preferred methodology is presented in this Revision. This report, NUREG/CR-6181, Rev. 1, therefore supersedes the earlier NUREG/CR-6181 published in August 1994. The specific systems addressed in this report are the auxiliary feedwater, the low-pressure injection, and the reactor coolant systems. The results provide a risk-informed ranking of components within these systems.
Risk Informed Margins Management as part of Risk Informed Safety Margin Characterization
Curtis Smith
2014-06-01
The ability to better characterize and quantify safety margin is important to improved decision making about Light Water Reactor (LWR) design, operation, and plant life extension. A systematic approach to characterization of safety margins and the subsequent margin management options represents a vital input to the licensee and regulatory analysis and decision making that will be involved. In addition, as research and development in the LWR Sustainability (LWRS) Program and other collaborative efforts yield new data, sensors, and improved scientific understanding of physical processes that govern the aging and degradation of plant SSCs needs and opportunities to better optimize plant safety and performance will become known. To support decision making related to economics, readability, and safety, the Risk Informed Safety Margin Characterization (RISMC) Pathway provides methods and tools that enable mitigation options known as risk informed margins management (RIMM) strategies.
Stanley E. Ritterbusch, et. al.
2003-01-29
OAK-B135 Research under this project addresses the barriers to long term use of nuclear-generated electricity in the United States. It was agreed that a very basic and significant change to the current method of design and regulation was needed. That is, it was believed that the cost reduction goal could not be met by fixing the current system (i.e., an evolutionary approach) and a new, more advanced approach for this project would be needed. It is believed that a completely new design and regulatory process would have to be developed--a ''clean sheet of paper'' approach. This new approach would start with risk-based methods, would establish probabilistic design criteria, and would implement defense-in-depth only when necessary (1) to meet public policy issues (e.g., use of a containment building no matter how low the probability of a large release is) and (2) to address uncertainties in probabilistic methods and equipment performance. This new approach is significantly different from the Nuclear Regulatory Commission's (NRC) current risk-informed program for operating plants. For our new approach, risk-based methods are the primary means for assuring plant safety, whereas in the NRC's current approach, defense-in-depth remains the primary means of assuring safety. The primary accomplishments in the first year--Phase 1 were (1) the establishment of a new, highly risk-informed design and regulatory framework, (2) the establishment of the preliminary version of the new, highly risk-informed design process, (3) core damage frequency predictions showing that, based on new, lower pipe rupture probabilities, the design of the emergency core cooling system equipment can be simplified without reducing plant safety, and (4) the initial development of methods for including uncertainties in a new integrated structures-systems design model. Under the new regulatory framework, options for the use of ''design basis accidents'' were evaluated. It is expected that design basis
NASA Technical Reports Server (NTRS)
Freed, Alan D.
1996-01-01
There are many aspects to consider when designing a Rosenbrock-Wanner-Wolfbrandt (ROW) method for the numerical integration of ordinary differential equations (ODE's) solving initial value problems (IVP's). The process can be simplified by constructing ROW methods around good Runge-Kutta (RK) methods. The formulation of a new, simple, embedded, third-order, ROW method demonstrates this design approach.
Progress toward risk informed regulation
Rogers, K.C.
1997-01-01
For the last several years, the NRC, with encouragement from the industry, has been moving in the direction of risk informed regulation. This is consistent with the regulatory principle of efficiency, formally adopted by the Nuclear Regulatory Commission in 1991, which requires that regulatory activities be consistent with the degree of risk reduction they achieve. Probabilistic risk analysis has become the tool of choice for selecting the best of several alternatives. Closely related to risk informed regulation is the development of performance based rules. Such rules focus on the end result to be achieved. They do not specify the process, but instead establish the goals to be reached and how the achievement of those goals is to be judged. The inspection and enforcement activity is based on whether or not the goals have been met. The author goes on to offer comments on the history of the development of this process and its probable development in the future. He also addresses some issues which must be resolved or at least acknowledged. The success of risk informed regulation ultimately depends on having sufficiently reliable data to allow quantification of regulatory alternatives in terms of relative risk. Perhaps the area of human reliability and organizational performance has the greatest potential for improvement in reactor safety. The ability to model human performance is significantly less developed that the ability to model mechanical or electrical systems. The move toward risk informed, performance based regulation provides an unusual, perhaps unique, opportunity to establish a more rational, more effective basis for regulation.
Polak, Louisa; Green, Judith
2015-01-01
Background A large literature informs guidance for GPs about communicating quantitative risk information so as to facilitate shared decision making. However, relatively little has been written about how patients utilise such information in practice. Aim To understand the role of quantitative risk information in patients’ accounts of decisions about taking statins. Design and setting This was a qualitative study, with participants recruited and interviewed in community settings. Method Semi-structured interviews were conducted with 34 participants aged >50 years, all of whom had been offered statins. Data were analysed thematically, using elements of the constant comparative method. Results Interviewees drew frequently on numerical test results to explain their decisions about preventive medication. In contrast, they seldom mentioned quantitative risk information, and never offered it as a rationale for action. Test results were spoken of as objects of concern despite an often-explicit absence of understanding, so lack of understanding seems unlikely to explain the non-use of risk estimates. Preventive medication was seen as ‘necessary’ either to treat test results, or because of personalised, unequivocal advice from a doctor. Conclusion This study’s findings call into question the assumption that people will heed and use numerical risk information once they understand it; these data highlight the need to consider the ways in which different kinds of knowledge are used in practice in everyday contexts. There was little evidence from this study that understanding probabilistic risk information was a necessary or valued condition for making decisions about statin use. PMID:25824187
Communicating risk information and warnings
Mileti, D. S.
1990-01-01
Major advances have occurred over the last 20 years about how to effectively communicate risk information and warnings to the public. These lessons have been hard won. Knowledge has mounted on the finding from social scientific studies of risk communication failures, successes and those which fell somewhere in between. Moreover, the last 2 decades have borne witness to the brith, cultivation, and blossoming of information sharing between those physical scientists who discover new information about risk and those communcation scientists who trace its diffusion and then measure pbulic reaction.
Air Risk Information Support Center
Shoaf, C.R.; Guth, D.J.
1990-12-31
The Air Risk Information Support Center (Air RISC) was initiated in early 1988 by the US Environmental Protection Agency`s (EPA) Office of Health and Environmental Assessment (OHEA) and the Office of Air Quality Planning and Standards (OAQPS) as a technology transfer effort that would focus on providing information to state and local environmental agencies and to EPA Regional Offices in the areas of health, risk, and exposure assessment for toxic air pollutants. Technical information is fostered and disseminated by Air RISCs three primary activities: (1) a {open_quotes}hotline{close_quotes}, (2) quick turn-around technical assistance projects, and (3) general technical guidance projects. 1 ref., 2 figs.
Wilson, David G.; Robinett, III, Rush D.
2012-02-21
A control system design method and concomitant control system comprising representing a physical apparatus to be controlled as a Hamiltonian system, determining elements of the Hamiltonian system representation which are power generators, power dissipators, and power storage devices, analyzing stability and performance of the Hamiltonian system based on the results of the determining step and determining necessary and sufficient conditions for stability of the Hamiltonian system, creating a stable control system based on the results of the analyzing step, and employing the resulting control system to control the physical apparatus.
Integrated risk information system (IRIS)
Tuxen, L.
1990-12-31
The Integrated Risk Information System (IRIS) is an electronic information system developed by the US Environmental Protection Agency (EPA) containing information related to health risk assessment. IRIS is the Agency`s primary vehicle for communication of chronic health hazard information that represents Agency consensus following comprehensive review by intra-Agency work groups. The original purpose for developing IRIS was to provide guidance to EPA personnel in making risk management decisions. This original purpose for developing IRIS was to guidance to EPA personnel in making risk management decisions. This role has expanded and evolved with wider access and use of the system. IRIS contains chemical-specific information in summary format for approximately 500 chemicals. IRIS is available to the general public on the National Library of Medicine`s Toxicology Data Network (TOXNET) and on diskettes through the National Technical Information Service (NTIS).
NASA Technical Reports Server (NTRS)
Pratt, T. W.; Adams, L. M.; Mehrotra, P.; Vanrosendale, J.; Voigt, R. G.; Patrick, M.
1983-01-01
The FEM-2 parallel computer is designed using methods differing from those ordinarily employed in parallel computer design. The major distinguishing aspects are: (1) a top-down rather than bottom-up design process; (2) the design considers the entire system structure in terms of layers of virtual machines; and (3) each layer of virtual machine is defined formally during the design process. The result is a complete hardware/software system design. The basic design method is discussed and the advantages of the method are considered. A status report on the FEM-2 design is included.
NASA Risk-Informed Decision Making Handbook
NASA Technical Reports Server (NTRS)
Dezfuli, Homayoon; Stamatelatos, Michael; Maggio, Gaspare; Everett, Christopher; Youngblood, Robert; Rutledge, Peter; Benjamin, Allan; Williams, Rodney; Smith, Curtis; Guarro, Sergio
2010-01-01
This handbook provides guidance for conducting risk-informed decision making in the context of NASA risk management (RM), with a focus on the types of direction-setting key decisions that are characteristic of the NASA program and project life cycles, and which produce derived requirements in accordance with existing systems engineering practices that flow down through the NASA organizational hierarchy. The guidance in this handbook is not meant to be prescriptive. Instead, it is meant to be general enough, and contain a sufficient diversity of examples, to enable the reader to adapt the methods as needed to the particular decision problems that he or she faces. The handbook highlights major issues to consider when making decisions in the presence of potentially significant uncertainty, so that the user is better able to recognize and avoid pitfalls that might otherwise be experienced.
Aircraft digital control design methods
NASA Technical Reports Server (NTRS)
Powell, J. D.; Parsons, E.; Tashker, M. G.
1976-01-01
Variations in design methods for aircraft digital flight control are evaluated and compared. The methods fall into two categories; those where the design is done in the continuous domain (or s plane) and those where the design is done in the discrete domain (or z plane). Design method fidelity is evaluated by examining closed loop root movement and the frequency response of the discretely controlled continuous aircraft. It was found that all methods provided acceptable performance for sample rates greater than 10 cps except the uncompensated s plane design method which was acceptable above 20 cps. A design procedure based on optimal control methods was proposed that provided the best fidelity at very slow sample rates and required no design iterations for changing sample rates.
RISK-INFORMED SAFETY MARGIN CHARACTERIZATION
Nam Dinh; Ronaldo Szilard
2009-07-01
The concept of safety margins has served as a fundamental principle in the design and operation of commercial nuclear power plants (NPPs). Defined as the minimum distance between a system’s “loading” and its “capacity”, plant design and operation is predicated on ensuring an adequate safety margin for safety-significant parameters (e.g., fuel cladding temperature, containment pressure, etc.) is provided over the spectrum of anticipated plant operating, transient and accident conditions. To meet the anticipated challenges associated with extending the operational lifetimes of the current fleet of operating NPPs, the United States Department of Energy (USDOE), the Idaho National Laboratory (INL) and the Electric Power Research Institute (EPRI) have developed a collaboration to conduct coordinated research to identify and address the technological challenges and opportunities that likely would affect the safe and economic operation of the existing NPP fleet over the postulated long-term time horizons. In this paper we describe a framework for developing and implementing a Risk-Informed Safety Margin Characterization (RISMC) approach to evaluate and manage changes in plant safety margins over long time horizons.
Risk-Informed Assessment Methodology Development and Application
Sung Goo Chi; Seok Jeong Park; Chul Jin Choi; Ritterbusch, S.E.; Jacob, M.C.
2002-07-01
Westinghouse Electric Company (WEC) has been working with Korea Power Engineering Company (KOPEC) on a US Department of Energy (DOE) sponsored Nuclear Energy Research Initiative (NERI) project through a collaborative agreement established for the domestic NERI program. The project deals with Risk-Informed Assessment (RIA) of regulatory and design requirements of future nuclear power plants. An objective of the RIA project is to develop a risk-informed design process, which focuses on identifying and incorporating advanced features into future nuclear power plants (NPPs) that would meet risk goals in a cost-effective manner. The RIA design methodology is proposed to accomplish this objective. This paper discusses the development of this methodology and demonstrates its application in the design of plant systems for future NPPs. Advanced conceptual plant systems consisting of an advanced Emergency Core Cooling System (ECCS) and Emergency Feedwater System (EFWS) for a NPP were developed and the risk-informed design process was exercised to demonstrate the viability and feasibility of the RIA design methodology. Best estimate Loss-of-Coolant Accident (LOCA) analyses were performed to validate the PSA success criteria for the NPP. The results of the analyses show that the PSA success criteria can be met using the advanced conceptual systems and that the RIA design methodology is a viable and appropriate means of designing key features of risk-significant NPP systems. (authors)
Aircraft digital control design methods
NASA Technical Reports Server (NTRS)
Tashker, M. G.; Powell, J. D.
1975-01-01
Investigations were conducted in two main areas: the first area is control system design, and the goals were to define the limits of 'digitized S-Plane design techniques' vs. sample rate, to show the results of a 'direct digital design technique', and to compare the two methods; the second area was to evaluate the roughness of autopilot designs parametrically versus sample rate. Goals of the first area were addressed by (1) an analysis of a 2nd order example using both design methods, (2) a linear analysis of the complete 737 aircraft with an autoland obtained using the digitized S-plane technique, (3) linear analysis of a high frequency 737 approximation with the autoland from a direct digital design technique, and (4) development of a simulation for evaluation of the autopilots with disturbances and nonlinearities included. Roughness evaluation was studied by defining an experiment to be carried out on the Langley motion simulator and coordinated with analysis at Stanford.
PRISM: a planned risk information seeking model.
Kahlor, LeeAnn
2010-06-01
Recent attention on health-related information seeking has focused primarily on information seeking within specific health and health risk contexts. This study attempts to shift some of that focus to individual-level variables that may impact health risk information seeking across contexts. To locate these variables, the researcher posits an integrated model, the Planned Risk Information Seeking Model (PRISM). The model, which treats risk information seeking as a deliberate (planned) behavior, maps variables found in the Theory of Planned Behavior (TPB; Ajzen, 1991) and the Risk Information Seeking and Processing Model (RISP; Griffin, Dunwoody, & Neuwirth, 1999), and posits linkages among those variables. This effort is further informed by Kahlor's (2007) Augmented RISP, the Theory of Motivated Information Management (Afifi & Weiner, 2004), the Comprehensive Model of Information Seeking (Johnson & Meischke, 1993), the Health Information Acquisition Model (Freimuth, Stein, & Kean, 1989), and the Extended Parallel Processing Model (Witte, 1998). The resulting integrated model accounted for 59% of the variance in health risk information-seeking intent and performed better than the TPB or the RISP alone. PMID:20512716
Stochastic Methods for Aircraft Design
NASA Technical Reports Server (NTRS)
Pelz, Richard B.; Ogot, Madara
1998-01-01
The global stochastic optimization method, simulated annealing (SA), was adapted and applied to various problems in aircraft design. The research was aimed at overcoming the problem of finding an optimal design in a space with multiple minima and roughness ubiquitous to numerically generated nonlinear objective functions. SA was modified to reduce the number of objective function evaluations for an optimal design, historically the main criticism of stochastic methods. SA was applied to many CFD/MDO problems including: low sonic-boom bodies, minimum drag on supersonic fore-bodies, minimum drag on supersonic aeroelastic fore-bodies, minimum drag on HSCT aeroelastic wings, FLOPS preliminary design code, another preliminary aircraft design study with vortex lattice aerodynamics, HSR complete aircraft aerodynamics. In every case, SA provided a simple, robust and reliable optimization method which found optimal designs in order 100 objective function evaluations. Perhaps most importantly, from this academic/industrial project, technology has been successfully transferred; this method is the method of choice for optimization problems at Northrop Grumman.
NASA Technical Reports Server (NTRS)
Guarro, Sergio B.
2010-01-01
This report validates and documents the detailed features and practical application of the framework for software intensive digital systems risk assessment and risk-informed safety assurance presented in the NASA PRA Procedures Guide for Managers and Practitioner. This framework, called herein the "Context-based Software Risk Model" (CSRM), enables the assessment of the contribution of software and software-intensive digital systems to overall system risk, in a manner which is entirely compatible and integrated with the format of a "standard" Probabilistic Risk Assessment (PRA), as currently documented and applied for NASA missions and applications. The CSRM also provides a risk-informed path and criteria for conducting organized and systematic digital system and software testing so that, within this risk-informed paradigm, the achievement of a quantitatively defined level of safety and mission success assurance may be targeted and demonstrated. The framework is based on the concept of context-dependent software risk scenarios and on the modeling of such scenarios via the use of traditional PRA techniques - i.e., event trees and fault trees - in combination with more advanced modeling devices such as the Dynamic Flowgraph Methodology (DFM) or other dynamic logic-modeling representations. The scenarios can be synthesized and quantified in a conditional logic and probabilistic formulation. The application of the CSRM method documented in this report refers to the MiniAERCam system designed and developed by the NASA Johnson Space Center.
Design method of supercavitating pumps
NASA Astrophysics Data System (ADS)
Kulagin, V.; Likhachev, D.; Li, F. C.
2016-05-01
The problem of effective supercavitating (SC) pump is solved, and optimum load distribution along the radius of the blade is found taking into account clearance, degree of cavitation development, influence of finite number of blades, and centrifugal forces. Sufficient accuracy can be obtained using the equivalent flat SC-grid for design of any SC-mechanisms, applying the “grid effect” coefficient and substituting the skewed flow calculated for grids of flat plates with the infinite attached cavitation caverns. This article gives the universal design method and provides an example of SC-pump design.
Risk-informed Maintenance for Non-coherent Systems
NASA Astrophysics Data System (ADS)
Tao, Ye
Probabilistic Safety Assessment (PSA) is a systematic and comprehensive methodology to evaluate risks associated with a complex engineered technological entity. The information provided by PSA has been increasingly implemented for regulatory purposes but rarely used in providing information for operation and maintenance activities. As one of the key parts in PSA, Fault Tree Analysis (FTA) attempts to model and analyze failure processes of engineering and biological systems. The fault trees are composed of logic diagrams that display the state of the system and are constructed using graphical design techniques. Risk Importance Measures (RIMs) are information that can be obtained from both qualitative and quantitative aspects of FTA. Components within a system can be ranked with respect to each specific criterion defined by each RIM. Through a RIM, a ranking of the components or basic events can be obtained and provide valuable information for risk-informed decision making. Various RIMs have been applied in various applications. In order to provide a thorough understanding of RIMs and interpret the results, they are categorized with respect to risk significance (RS) and safety significance (SS) in this thesis. This has also tied them into different maintenance activities. When RIMs are used for maintenance purposes, it is called risk-informed maintenance. On the other hand, the majority of work produced on the FTA method has been concentrated on failure logic diagrams restricted to the direct or implied use of AND and OR operators. Such systems are considered as coherent systems. However, the NOT logic can also contribute to the information produced by PSA. The importance analysis of non-coherent systems is rather limited, even though the field has received more and more attention over the years. The non-coherent systems introduce difficulties in both qualitative and quantitative assessment of the fault tree compared with the coherent systems. In this thesis, a set
DISPLACEMENT BASED SEISMIC DESIGN METHODS.
HOFMAYER,C.MILLER,C.WANG,Y.COSTELLO,J.
2003-07-15
A research effort was undertaken to determine the need for any changes to USNRC's seismic regulatory practice to reflect the move, in the earthquake engineering community, toward using expected displacement rather than force (or stress) as the basis for assessing design adequacy. The research explored the extent to which displacement based seismic design methods, such as given in FEMA 273, could be useful for reviewing nuclear power stations. Two structures common to nuclear power plants were chosen to compare the results of the analysis models used. The first structure is a four-story frame structure with shear walls providing the primary lateral load system, referred herein as the shear wall model. The second structure is the turbine building of the Diablo Canyon nuclear power plant. The models were analyzed using both displacement based (pushover) analysis and nonlinear dynamic analysis. In addition, for the shear wall model an elastic analysis with ductility factors applied was also performed. The objectives of the work were to compare the results between the analyses, and to develop insights regarding the work that would be needed before the displacement based analysis methodology could be considered applicable to facilities licensed by the NRC. A summary of the research results, which were published in NUREGICR-6719 in July 2001, is presented in this paper.
A historical perspective of risk-informed regulation
Campbell, P.L.
1996-12-01
In Federal studies, the process of using risk information is described as having two general components: (1) risk assessment - the application of credible scientific principles and statistical methods to develop estimates of the likely effects of natural phenomena and human factors and the characterization of these estimates in a form appropriate for the intended audience (e.g., agency decisionmakers, public); and (2) risk management - the process of weighing policy alternatives and selecting the most appropriate regulatory action, integrating the results of risk assessment with engineering data with social, economic, and political concerns to reach a decision. This paper discusses largely the second component.
Design of diffractive optical surfaces within the SMS design method
NASA Astrophysics Data System (ADS)
Mendes-Lopes, João.; Benítez, Pablo; Miñano, Juan C.
2015-08-01
The Simultaneous Multiple Surface (SMS) method was initially developed as a design method in Nonimaging Optics and later, the method was extended for designing Imaging Optics. We present the extension of the SMS method to design diffractive optical surfaces. This method involves the simultaneous calculation of N/2 diffractive surfaces, using the phase-shift properties of diffractive surfaces as an extra degree of freedom, such that N one-parameter wavefronts can be perfectly coupled. Moreover, the SMS method for diffractive surfaces is a direct method, i.e., it is not based in multi-parametric optimization techniques. Representative diffractive systems designed by the SMS method are presented.
An airfoil design method for viscous flows
NASA Technical Reports Server (NTRS)
Malone, J. B.; Narramore, J. C.; Sankar, L. N.
1990-01-01
An airfoil design procedure is described that has been incorporated into an existing two-dimensional Navier-Stokes airfoil analysis method. The resulting design method, an iterative procedure based on a residual-correction algorithm, permits the automated design of airfoil sections with prescribed surface pressure distributions. This paper describes the inverse design method and the technique used to specify target pressure distributions. An example airfoil design problem is described to demonstrate application of the inverse design procedure. It shows that this inverse design method develops useful airfoil configurations with a reasonable expenditure of computer resources.
RISK-INFORMED BALANCING OF SAFETY, NONPROLIFERATION, AND ECONOMICS FOR THE SFR
Apostolakis, George; Driscoll, Michael; Golay, Michael; Kadak, Andrew; Todreas, Neil; Aldmir, Tunc; Denning, Richard; Lineberry, Michael
2011-10-20
A substantial barrier to the implementation of Sodium-cooled Fast Reactor (SFR) technology in the short term is the perception that they would not be economically competitive with advanced light water reactors. With increased acceptance of risk-informed regulation, the opportunity exists to reduce the costs of a nuclear power plant at the design stage without applying excessive conservatism that is not needed in treating low risk events. In the report, NUREG-1860, the U.S. Nuclear Regulatory Commission describes developmental activities associated with a risk-informed, scenario-based technology neutral framework (TNF) for regulation. It provides quantitative yardsticks against which the adequacy of safety risks can be judged. We extend these concepts to treatment of proliferation risks. The objective of our project is to develop a risk-informed design process for minimizing the cost of electricity generation within constraints of adequate safety and proliferation risks. This report describes the design and use of this design optimization process within the context of reducing the capital cost and levelized cost of electricity production for a small (possibly modular) SFR. Our project provides not only an evaluation of the feasibility of a risk-informed design process but also a practical test of the applicability of the TNF to an actual advanced, non-LWR design. The report provides results of five safety related and one proliferation related case studies of innovative design alternatives. Applied to previously proposed SFR nuclear energy system concepts We find that the TNF provides a feasible initial basis for licensing new reactors. However, it is incomplete. We recommend improvements in terms of requiring acceptance standards for total safety risks, and we propose a framework for regulation of proliferation risks. We also demonstrate methods for evaluation of proliferation risks. We also suggest revisions to scenario-specific safety risk acceptance standards
Review of freeform TIR collimator design methods
NASA Astrophysics Data System (ADS)
Talpur, Taimoor; Herkommer, Alois
2016-04-01
Total internal reflection (TIR) collimators are essential illumination components providing high efficiency and uniformity in a compact geometry. Various illumination design methods have been developed for designing such collimators, including tailoring methods, design via optimization, the mapping and feedback method, and the simultaneous multiple surface (SMS) method. This paper provides an overview of the different methods and compares the performance of the methods along with their advantages and their limitations.
Computational methods for stealth design
Cable, V.P. )
1992-08-01
A review is presented of the utilization of computer models for stealth design toward the ultimate goal of designing and fielding an aircraft that remains undetected at any altitude and any range. Attention is given to the advancements achieved in computational tools and their utilization. Consideration is given to the development of supercomputers for large-scale scientific computing and the development of high-fidelity, 3D, radar-signature-prediction tools for complex shapes with nonmetallic and radar-penetrable materials.
Han, Paul K J; Hootsmans, Norbert; Neilson, Michael; Roy, Bethany; Kungel, Terence; Gutheil, Caitlin; Diefenbach, Michael; Hansen, Moritz
2013-01-01
Objective To explore the experiences of patients with prostate cancer with risk information and their perceptions of the value of personalised risk information in treatment decisions. Design A qualitative study was conducted using focus groups. Semistructured interviews explored participants’ experiences with using risk information, and their perceptions of the potential value of personalised risk information produced by clinical prediction models. Participants English-speaking patients, ages 54–82, diagnosed with prostate cancer within the past 3 years, residing in rural and non-rural geographic locations in Maine (USA), and attending prostate cancer patient support groups. Setting 6 focus groups were conducted with 27 patients; separate groups were held for patients with low-risk, medium-risk and high-risk disease defined by National Comprehensive Cancer Network guidelines. Results Several participants reported receiving risk information that was imprecise rather than precise, qualitative rather than quantitative, indirect rather than direct and focused on biomarker values rather than clinical outcomes. Some participants felt that personalised risk information could be useful in helping them make better informed decisions, but expressed scepticism about its value. Many participants favoured decision-making strategies that were heuristic-based and intuitive rather than risk-based and deliberative, and perceived other forms of evidence—emotions, recommendations of trusted physicians, personal narratives—as more reliable and valuable in treatment decisions. Conclusions Patients with prostate cancer appear to have little experience using personalised risk information, may favour heuristic-based over risk-based decision-making strategies and may perceive personalised risk information as less valuable than other types of evidence. These decision-making approaches and perceptions represent potential barriers to the clinical use of personalised risk information
Spacesuit Radiation Shield Design Methods
NASA Technical Reports Server (NTRS)
Wilson, John W.; Anderson, Brooke M.; Cucinotta, Francis A.; Ware, J.; Zeitlin, Cary J.
2006-01-01
Meeting radiation protection requirements during EVA is predominantly an operational issue with some potential considerations for temporary shelter. The issue of spacesuit shielding is mainly guided by the potential of accidental exposure when operational and temporary shelter considerations fail to maintain exposures within operational limits. In this case, very high exposure levels are possible which could result in observable health effects and even be life threatening. Under these assumptions, potential spacesuit radiation exposures have been studied using known historical solar particle events to gain insight on the usefulness of modification of spacesuit design in which the control of skin exposure is a critical design issue and reduction of blood forming organ exposure is desirable. Transition to a new spacesuit design including soft upper-torso and reconfigured life support hardware gives an opportunity to optimize the next generation spacesuit for reduced potential health effects during an accidental exposure.
Computational Methods in Nanostructure Design
NASA Astrophysics Data System (ADS)
Bellesia, Giovanni; Lampoudi, Sotiria; Shea, Joan-Emma
Self-assembling peptides can serve as building blocks for novel biomaterials. Replica exchange molecular dynamics simulations are a powerful means to probe the conformational space of these peptides. We discuss the theoretical foundations of this enhanced sampling method and its use in biomolecular simulations. We then apply this method to determine the monomeric conformations of the Alzheimer amyloid-β(12-28) peptide that can serve as initiation sites for aggregation.
Design for validation, based on formal methods
NASA Technical Reports Server (NTRS)
Butler, Ricky W.
1990-01-01
Validation of ultra-reliable systems decomposes into two subproblems: (1) quantification of probability of system failure due to physical failure; (2) establishing that Design Errors are not present. Methods of design, testing, and analysis of ultra-reliable software are discussed. It is concluded that a design-for-validation based on formal methods is needed for the digital flight control systems problem, and also that formal methods will play a major role in the development of future high reliability digital systems.
Communicating Cancer Risk Information: The Challenges of Uncertainty.
ERIC Educational Resources Information Center
Bottorff, Joan L.; Ratner, Pamela A.; Johnson, Joy L.; Lovato, Chris Y.; Joab, S. Amanda
1998-01-01
Accurate and sensitive communication of cancer-risk information is important. Based on a literature review of 75 research reports, expert opinion papers, and clinical protocols, a synthesis of what is known about the communication of cancer-risk information is presented. Relevance of information to those not tested is discussed. (Author/EMK)
LaChance, Jeffrey L.; Houf, William G.; Fluer, Inc., Paso Robels, CA; Fluer, Larry; Middleton, Bobby
2009-03-01
The development of a set of safety codes and standards for hydrogen facilities is necessary to ensure they are designed and operated safely. To help ensure that a hydrogen facility meets an acceptable level of risk, code and standard development organizations are tilizing risk-informed concepts in developing hydrogen codes and standards.
HTGR analytical methods and design verification
Neylan, A.J.; Northup, T.E.
1982-05-01
Analytical methods for the high-temperature gas-cooled reactor (HTGR) include development, update, verification, documentation, and maintenance of all computer codes for HTGR design and analysis. This paper presents selected nuclear, structural mechanics, seismic, and systems analytical methods related to the HTGR core. This paper also reviews design verification tests in the reactor core, reactor internals, steam generator, and thermal barrier.
Applications of a transonic wing design method
NASA Technical Reports Server (NTRS)
Campbell, Richard L.; Smith, Leigh A.
1989-01-01
A method for designing wings and airfoils at transonic speeds using a predictor/corrector approach was developed. The procedure iterates between an aerodynamic code, which predicts the flow about a given geometry, and the design module, which compares the calculated and target pressure distributions and modifies the geometry using an algorithm that relates differences in pressure to a change in surface curvature. The modular nature of the design method makes it relatively simple to couple it to any analysis method. The iterative approach allows the design process and aerodynamic analysis to converge in parallel, significantly reducing the time required to reach a final design. Viscous and static aeroelastic effects can also be accounted for during the design or as a post-design correction. Results from several pilot design codes indicated that the method accurately reproduced pressure distributions as well as the coordinates of a given airfoil or wing by modifying an initial contour. The codes were applied to supercritical as well as conventional airfoils, forward- and aft-swept transport wings, and moderate-to-highly swept fighter wings. The design method was found to be robust and efficient, even for cases having fairly strong shocks.
Impeller blade design method for centrifugal compressors
NASA Technical Reports Server (NTRS)
Jansen, W.; Kirschner, A. M.
1974-01-01
The design of a centrifugal impeller with blades that are aerodynamically efficient, easy to manufacture, and mechanically sound is discussed. The blade design method described here satisfies the first two criteria and with a judicious choice of certain variables will also satisfy stress considerations. The blade shape is generated by specifying surface velocity distributions and consists of straight-line elements that connect points at hub and shroud. The method may be used to design radially elemented and backward-swept blades. The background, a brief account of the theory, and a sample design are described.
NASA Astrophysics Data System (ADS)
Jeuken, Ad; Mendoza, Guillermo; Matthews, John; Ray, Patrick; Haasnoot, Marjolijn; Gilroy, Kristin; Olsen, Rolf; Kucharski, John; Stakhiv, Gene; Cushing, Janet; Brown, Casey
2016-04-01
over time. They are part of the Dutch adaptive planning approach Adaptive Delta Management, executed and develop by the Dutch Delta program. Both decision scaling and adaptation pathways have been piloted in studies worldwide. The objective of CRIDA is to mainstream effective climate adaptation for professional water managers. The CRIDA publication, due in april 2016, follows the generic water design planning design cycle. At each step, CRIDA describes stepwise guidance for incorporating climate robustness: problem definition, stress test, alternatives formulation and recommendation, evaluation and selection. In the presentation the origin, goal, steps and practical tools available at each step of CRIDA will be explained. In two other abstracts ("Climate Risk Informed Decision Analysis: A Hypothetical Application to the Waas Region" by Gilroy et al., "The Application of Climate Risk Informed Decision Analysis to the Ioland Water Treatment Plant in Lusaka, Zambia, by Kucharski et al.), the application of CRIDA to cases is explained
Model reduction methods for control design
NASA Technical Reports Server (NTRS)
Dunipace, K. R.
1988-01-01
Several different model reduction methods are developed and detailed implementation information is provided for those methods. Command files to implement the model reduction methods in a proprietary control law analysis and design package are presented. A comparison and discussion of the various reduction techniques is included.
Mixed Methods Research Designs in Counseling Psychology
ERIC Educational Resources Information Center
Hanson, William E.; Creswell, John W.; Clark, Vicki L. Plano; Petska, Kelly S.; Creswell, David J.
2005-01-01
With the increased popularity of qualitative research, researchers in counseling psychology are expanding their methodologies to include mixed methods designs. These designs involve the collection, analysis, and integration of quantitative and qualitative data in a single or multiphase study. This article presents an overview of mixed methods…
Airbreathing hypersonic vehicle design and analysis methods
NASA Technical Reports Server (NTRS)
Lockwood, Mary Kae; Petley, Dennis H.; Hunt, James L.; Martin, John G.
1996-01-01
The design, analysis, and optimization of airbreathing hypersonic vehicles requires analyses involving many highly coupled disciplines at levels of accuracy exceeding those traditionally considered in a conceptual or preliminary-level design. Discipline analysis methods including propulsion, structures, thermal management, geometry, aerodynamics, performance, synthesis, sizing, closure, and cost are discussed. Also, the on-going integration of these methods into a working environment, known as HOLIST, is described.
Risk-informed inservice test activities at the NRC
Fischer, D.; Cheok, M.; Hsia, A.
1996-12-01
The operational readiness of certain safety-related components is vital to the safe operation of nuclear power plants. Inservice testing (IST) is one of the mechanisms used by licensees to ensure this readiness. In the past, the type and frequency of IST have been based on the collective best judgment of the NRC and industry in an ASME Code consensus process and NRC rulemaking process. Furthermore, IST requirements have not explicitly considered unique component and system designs and contribution to overall plant risk. Because of the general nature of ASME Code test requirements and non-reliance on risk estimates, current IST requirements may not adequately emphasize testing those components that are most important to safety and may overly emphasize testing of less safety significant components. Nuclear power plant licensees are currently interested in optimizing testing by applying resources in more safety significant areas and, where appropriate, reducing measures in less safety-significant areas. They are interested in maintaining system availability and reducing overall maintenance costs in ways that do not adversely affect safety. The NRC has been interested in using probabilistic, as an adjunct to deterministic, techniques to help define the scope, type and frequency of IST. The development of risk-informed IST programs has the potential to optimize the use of NRC and industry resources without adverse affect on safety.
Development of a hydraulic turbine design method
NASA Astrophysics Data System (ADS)
Kassanos, Ioannis; Anagnostopoulos, John; Papantonis, Dimitris
2013-10-01
In this paper a hydraulic turbine parametric design method is presented which is based on the combination of traditional methods and parametric surface modeling techniques. The blade of the turbine runner is described using Bezier surfaces for the definition of the meridional plane as well as the blade angle distribution, and a thickness distribution applied normal to the mean blade surface. In this way, it is possible to define parametrically the whole runner using a relatively small number of design parameters, compared to conventional methods. The above definition is then combined with a commercial CFD software and a stochastic optimization algorithm towards the development of an automated design optimization procedure. The process is demonstrated with the design of a Francis turbine runner.
Preliminary aerothermodynamic design method for hypersonic vehicles
NASA Technical Reports Server (NTRS)
Harloff, G. J.; Petrie, S. L.
1987-01-01
Preliminary design methods are presented for vehicle aerothermodynamics. Predictions are made for Shuttle orbiter, a Mach 6 transport vehicle and a high-speed missile configuration. Rapid and accurate methods are discussed for obtaining aerodynamic coefficients and heat transfer rates for laminar and turbulent flows for vehicles at high angles of attack and hypersonic Mach numbers.
Combinatorial protein design strategies using computational methods.
Kono, Hidetoshi; Wang, Wei; Saven, Jeffery G
2007-01-01
Computational methods continue to facilitate efforts in protein design. Most of this work has focused on searching sequence space to identify one or a few sequences compatible with a given structure and functionality. Probabilistic computational methods provide information regarding the range of amino acid variability permitted by desired functional and structural constraints. Such methods may be used to guide the construction of both individual sequences and combinatorial libraries of proteins. PMID:17041256
Multidisciplinary Optimization Methods for Aircraft Preliminary Design
NASA Technical Reports Server (NTRS)
Kroo, Ilan; Altus, Steve; Braun, Robert; Gage, Peter; Sobieski, Ian
1994-01-01
This paper describes a research program aimed at improved methods for multidisciplinary design and optimization of large-scale aeronautical systems. The research involves new approaches to system decomposition, interdisciplinary communication, and methods of exploiting coarse-grained parallelism for analysis and optimization. A new architecture, that involves a tight coupling between optimization and analysis, is intended to improve efficiency while simplifying the structure of multidisciplinary, computation-intensive design problems involving many analysis disciplines and perhaps hundreds of design variables. Work in two areas is described here: system decomposition using compatibility constraints to simplify the analysis structure and take advantage of coarse-grained parallelism; and collaborative optimization, a decomposition of the optimization process to permit parallel design and to simplify interdisciplinary communication requirements.
Axisymmetric inlet minimum weight design method
NASA Technical Reports Server (NTRS)
Nadell, Shari-Beth
1995-01-01
An analytical method for determining the minimum weight design of an axisymmetric supersonic inlet has been developed. The goal of this method development project was to improve the ability to predict the weight of high-speed inlets in conceptual and preliminary design. The initial model was developed using information that was available from inlet conceptual design tools (e.g., the inlet internal and external geometries and pressure distributions). Stiffened shell construction was assumed. Mass properties were computed by analyzing a parametric cubic curve representation of the inlet geometry. Design loads and stresses were developed at analysis stations along the length of the inlet. The equivalent minimum structural thicknesses for both shell and frame structures required to support the maximum loads produced by various load conditions were then determined. Preliminary results indicated that inlet hammershock pressures produced the critical design load condition for a significant portion of the inlet. By improving the accuracy of inlet weight predictions, the method will improve the fidelity of propulsion and vehicle design studies and increase the accuracy of weight versus cost studies.
Analysis Method for Quantifying Vehicle Design Goals
NASA Technical Reports Server (NTRS)
Fimognari, Peter; Eskridge, Richard; Martin, Adam; Lee, Michael
2007-01-01
A document discusses a method for using Design Structure Matrices (DSM), coupled with high-level tools representing important life-cycle parameters, to comprehensively conceptualize a flight/ground space transportation system design by dealing with such variables as performance, up-front costs, downstream operations costs, and reliability. This approach also weighs operational approaches based on their effect on upstream design variables so that it is possible to readily, yet defensively, establish linkages between operations and these upstream variables. To avoid the large range of problems that have defeated previous methods of dealing with the complex problems of transportation design, and to cut down the inefficient use of resources, the method described in the document identifies those areas that are of sufficient promise and that provide a higher grade of analysis for those issues, as well as the linkages at issue between operations and other factors. Ultimately, the system is designed to save resources and time, and allows for the evolution of operable space transportation system technology, and design and conceptual system approach targets.
Optimization methods applied to hybrid vehicle design
NASA Technical Reports Server (NTRS)
Donoghue, J. F.; Burghart, J. H.
1983-01-01
The use of optimization methods as an effective design tool in the design of hybrid vehicle propulsion systems is demonstrated. Optimization techniques were used to select values for three design parameters (battery weight, heat engine power rating and power split between the two on-board energy sources) such that various measures of vehicle performance (acquisition cost, life cycle cost and petroleum consumption) were optimized. The apporach produced designs which were often significant improvements over hybrid designs already reported on in the literature. The principal conclusions are as follows. First, it was found that the strategy used to split the required power between the two on-board energy sources can have a significant effect on life cycle cost and petroleum consumption. Second, the optimization program should be constructed so that performance measures and design variables can be easily changed. Third, the vehicle simulation program has a significant effect on the computer run time of the overall optimization program; run time can be significantly reduced by proper design of the types of trips the vehicle takes in a one year period. Fourth, care must be taken in designing the cost and constraint expressions which are used in the optimization so that they are relatively smooth functions of the design variables. Fifth, proper handling of constraints on battery weight and heat engine rating, variables which must be large enough to meet power demands, is particularly important for the success of an optimization study. Finally, the principal conclusion is that optimization methods provide a practical tool for carrying out the design of a hybrid vehicle propulsion system.
Effects of baseline risk information on social and individual choices.
Gyrd-Hansen, Dorte; Kristiansen, Ivar Sønbø; Nexøe, Jørgen; Nielsen, Jesper Bo
2002-01-01
This article analyzes preferences for risk reductions in the context of individual and societal decision making. The effect of information on baseline risk is analyzed in both contexts. The results indicate that if individuals are to imagine that they suffer from 1 low-risk and 1 high-risk ailment, and are offered a specified identical absolute risk reduction, a majority will ceteris paribus opt for treatment of the low-risk ailment. A different preference structure is elicited when priority questions are framed as social choices. Here, a majority will prefer to treat the high-risk group of patients. The preference reversal demonstrates the extent to which baseline risk information can influence preferences in different choice settings. It is argued that presentation of baseline risk information may induce framing effects that lead to nonoptimal resource allocations. A solution to this problem may be to not present group-specific baseline risk information when eliciting preferences. PMID:11833667
A sociotechnical method for designing work systems.
Waterson, Patrick E; Older Gray, Melanie T; Clegg, Chris W
2002-01-01
The paper describes a new method for allocating work between and among humans and machines. The method consists of a series of stages, which cover how the overall work system should be organized and designed; how tasks within the work system should be allocated (human-human allocations); and how tasks involving the use of technology should be allocated (human-machine allocations). The method makes use of a series of decision criteria that allow end users to consider a range of factors relevant to function allocation, including aspects of job, organizational, and technological design. The method is described in detail using an example drawn from a workshop involving the redesign of a naval command and control (C2) subsystem. We also report preliminary details of the evaluation of the method, based on the views of participants at the workshop. A final section outlines the contribution of the work in terms of current theoretical developments within the domain of function allocation. The method has been applied to the domain of naval C2 systems; however, it is also designed for generic use within function allocation and sociotechnical work systems. PMID:12502156
MAST Propellant and Delivery System Design Methods
NASA Technical Reports Server (NTRS)
Nadeem, Uzair; Mc Cleskey, Carey M.
2015-01-01
A Mars Aerospace Taxi (MAST) concept and propellant storage and delivery case study is undergoing investigation by NASA's Element Design and Architectural Impact (EDAI) design and analysis forum. The MAST lander concept envisions landing with its ascent propellant storage tanks empty and supplying these reusable Mars landers with propellant that is generated and transferred while on the Mars surface. The report provides an overview of the data derived from modeling between different methods of propellant line routing (or "lining") and differentiate the resulting design and operations complexity of fluid and gaseous paths based on a given set of fluid sources and destinations. The EDAI team desires a rough-order-magnitude algorithm for estimating the lining characteristics (i.e., the plumbing mass and complexity) associated different numbers of vehicle propellant sources and destinations. This paper explored the feasibility of preparing a mathematically sound algorithm for this purpose, and offers a method for the EDAI team to implement.
Standardized Radiation Shield Design Methods: 2005 HZETRN
NASA Technical Reports Server (NTRS)
Wilson, John W.; Tripathi, Ram K.; Badavi, Francis F.; Cucinotta, Francis A.
2006-01-01
Research committed by the Langley Research Center through 1995 resulting in the HZETRN code provides the current basis for shield design methods according to NASA STD-3000 (2005). With this new prominence, the database, basic numerical procedures, and algorithms are being re-examined with new methods of verification and validation being implemented to capture a well defined algorithm for engineering design processes to be used in this early development phase of the Bush initiative. This process provides the methodology to transform the 1995 HZETRN research code into the 2005 HZETRN engineering code to be available for these early design processes. In this paper, we will review the basic derivations including new corrections to the codes to insure improved numerical stability and provide benchmarks for code verification.
Approaches to cancer assessment in EPA's Integrated Risk Information System
Gehlhaus, Martin W.; Gift, Jeffrey S.; Hogan, Karen A.; Kopylev, Leonid; Schlosser, Paul M.; Kadry, Abdel-Razak
2011-07-15
The U.S. Environmental Protection Agency's (EPA) Integrated Risk Information System (IRIS) Program develops assessments of health effects that may result from chronic exposure to chemicals in the environment. The IRIS database contains more than 540 assessments. When supported by available data, IRIS assessments provide quantitative analyses of carcinogenic effects. Since publication of EPA's 2005 Guidelines for Carcinogen Risk Assessment, IRIS cancer assessments have implemented new approaches recommended in these guidelines and expanded the use of complex scientific methods to perform quantitative dose-response assessments. Two case studies of the application of the mode of action framework from the 2005 Cancer Guidelines are presented in this paper. The first is a case study of 1,2,3-trichloropropane, as an example of a chemical with a mutagenic mode of carcinogenic action thus warranting the application of age-dependent adjustment factors for early-life exposure; the second is a case study of ethylene glycol monobutyl ether, as an example of a chemical with a carcinogenic action consistent with a nonlinear extrapolation approach. The use of physiologically based pharmacokinetic (PBPK) modeling to quantify interindividual variability and account for human parameter uncertainty as part of a quantitative cancer assessment is illustrated using a case study involving probabilistic PBPK modeling for dichloromethane. We also discuss statistical issues in assessing trends and model fit for tumor dose-response data, analysis of the combined risk from multiple types of tumors, and application of life-table methods for using human data to derive cancer risk estimates. These issues reflect the complexity and challenges faced in assessing the carcinogenic risks from exposure to environmental chemicals, and provide a view of the current trends in IRIS carcinogenicity risk assessment.
Acoustic Treatment Design Scaling Methods. Phase 2
NASA Technical Reports Server (NTRS)
Clark, L. (Technical Monitor); Parrott, T. (Technical Monitor); Jones, M. (Technical Monitor); Kraft, R. E.; Yu, J.; Kwan, H. W.; Beer, B.; Seybert, A. F.; Tathavadekar, P.
2003-01-01
The ability to design, build and test miniaturized acoustic treatment panels on scale model fan rigs representative of full scale engines provides not only cost-savings, but also an opportunity to optimize the treatment by allowing multiple tests. To use scale model treatment as a design tool, the impedance of the sub-scale liner must be known with confidence. This study was aimed at developing impedance measurement methods for high frequencies. A normal incidence impedance tube method that extends the upper frequency range to 25,000 Hz. without grazing flow effects was evaluated. The free field method was investigated as a potential high frequency technique. The potential of the two-microphone in-situ impedance measurement method was evaluated in the presence of grazing flow. Difficulties in achieving the high frequency goals were encountered in all methods. Results of developing a time-domain finite difference resonator impedance model indicated that a re-interpretation of the empirical fluid mechanical models used in the frequency domain model for nonlinear resistance and mass reactance may be required. A scale model treatment design that could be tested on the Universal Propulsion Simulator vehicle was proposed.
3. 6 simplified methods for design
Nickell, R.E.; Yahr, G.T.
1981-01-01
Simplified design analysis methods for elevated temperature construction are classified and reviewed. Because the major impetus for developing elevated temperature design methodology during the past ten years has been the LMFBR program, considerable emphasis is placed upon results from this source. The operating characteristics of the LMFBR are such that cycles of severe transient thermal stresses can be interspersed with normal elevated temperature operational periods of significant duration, leading to a combination of plastic and creep deformation. The various simplified methods are organized into two general categories, depending upon whether it is the material, or constitutive, model that is reduced, or the geometric modeling that is simplified. Because the elastic representation of material behavior is so prevalent, an entire section is devoted to elastic analysis methods. Finally, the validation of the simplified procedures is discussed.
Geometric methods for the design of mechanisms
NASA Astrophysics Data System (ADS)
Stokes, Ann Westagard
1993-01-01
Challenges posed by the process of designing robotic mechanisms have provided a new impetus to research in the classical subjects of kinematics, elastic analysis, and multibody dynamics. Historically, mechanism designers have considered these areas of analysis to be generally separate and distinct sciences. However, there are significant classes of problems which require a combination of these methods to arrive at a satisfactory solution. For example, both the compliance and the inertia distribution strongly influence the performance of a robotic manipulator. In this thesis, geometric methods are applied to the analysis of mechanisms where kinematics, elasticity, and dynamics play fundamental and interactive roles. Tools for the mathematical analysis, design, and optimization of a class of holonomic and nonholonomic mechanisms are developed. Specific contributions of this thesis include a network theory for elasto-kinematic systems. The applicability of the network theory is demonstrated by employing it to calculate the optimal distribution of joint compliance in a serial manipulator. In addition, the advantage of applying Lie group theoretic approaches to mechanisms requiring specific dynamic properties is demonstrated by extending Brockett's product of exponentials formula to the domain of dynamics. Conditions for the design of manipulators having inertia matrices which are constant in joint angle coordinates are developed. Finally, analysis and design techniques are developed for a class of mechanisms which rectify oscillations into secular motions. These techniques are applied to the analysis of free-floating chains that can reorient themselves in zero angular momentum processes and to the analysis of rattleback tops.
Reliability Methods for Shield Design Process
NASA Technical Reports Server (NTRS)
Tripathi, R. K.; Wilson, J. W.
2002-01-01
Providing protection against the hazards of space radiation is a major challenge to the exploration and development of space. The great cost of added radiation shielding is a potential limiting factor in deep space operations. In this enabling technology, we have developed methods for optimized shield design over multi-segmented missions involving multiple work and living areas in the transport and duty phase of space missions. The total shield mass over all pieces of equipment and habitats is optimized subject to career dose and dose rate constraints. An important component of this technology is the estimation of two most commonly identified uncertainties in radiation shield design, the shielding properties of materials used and the understanding of the biological response of the astronaut to the radiation leaking through the materials into the living space. The largest uncertainty, of course, is in the biological response to especially high charge and energy (HZE) ions of the galactic cosmic rays. These uncertainties are blended with the optimization design procedure to formulate reliability-based methods for shield design processes. The details of the methods will be discussed.
A risk-informed approach to safety margins analysis
Curtis Smith; Diego Mandelli
2013-07-01
The Risk Informed Safety Margins Characterization (RISMC) Pathway is a systematic approach developed to characterize and quantify safety margins of nuclear power plant structures, systems and components. The model has been tested on the Advanced Test Reactor (ATR) at Idaho National Lab.
Waterflooding injectate design systems and methods
Brady, Patrick V.; Krumhansl, James L.
2014-08-19
A method of designing an injectate to be used in a waterflooding operation is disclosed. One aspect includes specifying data representative of chemical characteristics of a liquid hydrocarbon, a connate, and a reservoir rock, of a subterranean reservoir. Charged species at an interface of the liquid hydrocarbon are determined based on the specified data by evaluating at least one chemical reaction. Charged species at an interface of the reservoir rock are determined based on the specified data by evaluating at least one chemical reaction. An extent of surface complexation between the charged species at the interfaces of the liquid hydrocarbon and the reservoir rock is determined by evaluating at least one surface complexation reaction. The injectate is designed and is operable to decrease the extent of surface complexation between the charged species at interfaces of the liquid hydrocarbon and the reservoir rock. Other methods, apparatus, and systems are disclosed.
An improved design method for EPC middleware
NASA Astrophysics Data System (ADS)
Lou, Guohuan; Xu, Ran; Yang, Chunming
2014-04-01
For currently existed problems and difficulties during the small and medium enterprises use EPC (Electronic Product Code) ALE (Application Level Events) specification to achieved middleware, based on the analysis of principle of EPC Middleware, an improved design method for EPC middleware is presented. This method combines the powerful function of MySQL database, uses database to connect reader-writer with upper application system, instead of development of ALE application program interface to achieve a middleware with general function. This structure is simple and easy to implement and maintain. Under this structure, different types of reader-writers added can be configured conveniently and the expandability of the system is improved.
Design methods of rhombic tensegrity structures
NASA Astrophysics Data System (ADS)
Feng, Xi-Qiao; Li, Yue; Cao, Yan-Ping; Yu, Shou-Wen; Gu, Yuan-Tong
2010-08-01
As a special type of novel flexible structures, tensegrity holds promise for many potential applications in such fields as materials science, biomechanics, civil and aerospace engineering. Rhombic systems are an important class of tensegrity structures, in which each bar constitutes the longest diagonal of a rhombus of four strings. In this paper, we address the design methods of rhombic structures based on the idea that many tensegrity structures can be constructed by assembling one-bar elementary cells. By analyzing the properties of rhombic cells, we first develop two novel schemes, namely, direct enumeration scheme and cell-substitution scheme. In addition, a facile and efficient method is presented to integrate several rhombic systems into a larger tensegrity structure. To illustrate the applications of these methods, some novel rhombic tensegrity structures are constructed.
Direct optimization method for reentry trajectory design
NASA Astrophysics Data System (ADS)
Jallade, S.; Huber, P.; Potti, J.; Dutruel-Lecohier, G.
The software package called `Reentry and Atmospheric Transfer Trajectory' (RATT) was developed under ESA contract for the design of atmospheric trajectories. It includes four software TOP (Trajectory OPtimization) programs, which optimize reentry and aeroassisted transfer trajectories. 6FD and 3FD (6 and 3 degrees of freedom Flight Dynamic) are devoted to the simulation of the trajectory. SCA (Sensitivity and Covariance Analysis) performs covariance analysis on a given trajectory with respect to different uncertainties and error sources. TOP provides the optimum guidance law of a three degree of freedom reentry of aeroassisted transfer (AAOT) trajectories. Deorbit and reorbit impulses (if necessary) can be taken into account in the optimization. A wide choice of cost function is available to the user such as the integrated heat flux, or the sum of the velocity impulses, or a linear combination of both of them for trajectory and vehicle design. The crossrange and the downrange can be maximized during reentry trajectory. Path constraints are available on the load factor, the heat flux and the dynamic pressure. Results on these proposed options are presented. TOPPHY is the part of the TOP software corresponding to the definition and the computation of the optimization problemphysics. TOPPHY can interface with several optimizes with dynamic solvers: TOPOP and TROPIC using direct collocation methods and PROMIS using direct multiple shooting method. TOPOP was developed in the frame of this contract, it uses Hermite polynomials for the collocation method and the NPSOL optimizer from the NAG library. Both TROPIC and PROMIS were developed by the DLR (Deutsche Forschungsanstalt fuer Luft und Raumfahrt) and use the SLSQP optimizer. For the dynamic equation resolution, TROPIC uses a collocation method with Splines and PROMIS uses a multiple shooting method with finite differences. The three different optimizers including dynamics were tested on the reentry trajectory of the
Methods for structural design at elevated temperatures
NASA Technical Reports Server (NTRS)
Ellison, A. M.; Jones, W. E., Jr.; Leimbach, K. R.
1973-01-01
A procedure which can be used to design elevated temperature structures is discussed. The desired goal is to have the same confidence in the structural integrity at elevated temperature as the factor of safety gives on mechanical loads at room temperature. Methods of design and analysis for creep, creep rupture, and creep buckling are presented. Example problems are included to illustrate the analytical methods. Creep data for some common structural materials are presented. Appendix B is description, user's manual, and listing for the creep analysis program. The program predicts time to a given creep or to creep rupture for a material subjected to a specified stress-temperature-time spectrum. Fatigue at elevated temperature is discussed. Methods of analysis for high stress-low cycle fatigue, fatigue below the creep range, and fatigue in the creep range are included. The interaction of thermal fatigue and mechanical loads is considered, and a detailed approach to fatigue analysis is given for structures operating below the creep range.
Curtis Smith; James Knudsen; Kellie Kvarfordt; Ted Wood
2008-08-01
The Idaho National Laboratory is a primary developer of probabilistic risk and reliability analysis (PRRA) tools, dating back over 35 years. Evolving from mainframe-based software, the current state-of-the-practice has lead to the creation of the SAPHIRE software. Currently, agencies such as the Nuclear Regulatory Commission, the National Aeronautics and Aerospace Agency, the Department of Energy, and the Department of Defense use version 7 of the SAPHIRE software for many of their risk-informed activities. In order to better understand and appreciate the power of software as part of risk-informed applications, we need to recall that our current analysis methods and solution methods have built upon pioneering work done 30 to 40 years ago. We contrast this work with the current capabilities in the SAPHIRE analysis package. As part of this discussion, we provide information for both the typical features and special analysis capabilities which are available. We also present the application and results typically found with state-of-the-practice PRRA models. By providing both a high-level and detailed look at the SAPHIRE software, we give a snapshot in time for the current use of software tools in a risk-informed decision arena.
Design analysis, robust methods, and stress classification
Bees, W.J.
1993-01-01
This special edition publication volume is comprised of papers presented at the 1993 ASME Pressure Vessels and Piping Conference, July 25--29, 1993 in Denver, Colorado. The papers were prepared for presentations in technical sessions developed under the auspices of the PVPD Committees on Computer Technology, Design and Analysis, Operations Applications and Components. The topics included are: Analysis of Pressure Vessels and Components; Expansion Joints; Robust Methods; Stress Classification; and Non-Linear Analysis. Individual papers have been processed separately for inclusion in the appropriate data bases.
Pharmaceutical websites and the communication of risk information.
Davis, Joel J; Cross, Emily; Crowley, John
2007-01-01
This study examines the pharmaceutical websites of 44 leading direct-to-consumer (DTC) advertised drugs to determine the extent to which risk information was completely communicated. Three operational definitions of "completeness" were used: communication of the single highest incidence side effect, communication of top three highest incidence side effects, and communication of side effects with incidence of >or= 10% (all measured in terms of absolute percentage). Results indicated that regardless of the measures used, pharmaceutical websites are unlikely to completely communicate risk information. About two thirds of all sites communicated the single highest incidence side effect or all top three side effects. For drugs with side effects at >or= 10% incidence, only about half of their websites fully reported all effects at this level of incidence. Implications for advertisers and regulatory agencies are presented. PMID:17365347
Needs for Risk Informing Environmental Cleanup Decision Making - 13613
Zhu, Ming; Moorer, Richard
2013-07-01
This paper discusses the needs for risk informing decision making by the U.S. Department of Energy (DOE) Office of Environmental Management (EM). The mission of the DOE EM is to complete the safe cleanup of the environmental legacy brought about from the nation's five decades of nuclear weapons development and production and nuclear energy research. This work represents some of the most technically challenging and complex cleanup efforts in the world and is projected to require the investment of billions of dollars and several decades to complete. Quantitative assessments of health and environmental risks play an important role in work prioritization and cleanup decisions of these challenging environmental cleanup and closure projects. The risk assessments often involve evaluation of performance of integrated engineered barriers and natural systems over a period of hundreds to thousands of years, when subject to complex geo-environmental transformation processes resulting from remediation and disposal actions. The requirement of resource investments for the cleanup efforts and the associated technical challenges have subjected the EM program to continuous scrutiny by oversight entities. Recent DOE reviews recommended application of a risk-informed approach throughout the EM complex for improved targeting of resources. The idea behind this recommendation is that by using risk-informed approaches to prioritize work scope, the available resources can be best utilized to reduce environmental and health risks across the EM complex, while maintaining the momentum of the overall EM cleanup program at a sustainable level. In response to these recommendations, EM is re-examining its work portfolio and key decision making with risk insights for the major sites. This paper summarizes the review findings and recommendations from the DOE internal reviews, discusses the needs for risk informing the EM portfolio and makes an attempt to identify topics for R and D in integrated
Design Method and Calibration of Moulinet
NASA Astrophysics Data System (ADS)
Itoh, Hirokazu; Yamada, Hirokazu; Udagawa, Sinsuke
The formula for obtaining the absorption horsepower of a Moulinet was rewritten, and the physical meaning of the constant in the formula was clarified. Based on this study, the design method of the Moulinet and the calibration method of the Moulinet that was performed after manufacture were verified experimentally. Consequently, the following was clarified; (1) If the propeller power coefficient was taken to be the proportionality constant, the absorption horsepower of the Moulinet was proportional to the cube of the revolution speed, and the fifth power of the Moulinet diameter. (2) If the Moulinet design was geometrically similar to the standard dimensions of the Aviation Technical Research Center's type-6 Moulinet, the proportionality constant C1 given in the reference could be used, and the absorption horsepower of the Moulinet was proportional to the cube of the revolution speed, the cube of the Moulinet diameter, and the side projection area of the Moulinet. (3) The proportionality constant C1 was proportional to the propeller power coefficient CP.
Code of Federal Regulations, 2013 CFR
2013-01-01
... whose expertise includes, at a minimum, PRA, safety analysis, plant operation, design engineering, and..., systems and components for nuclear power reactors. 50.69 Section 50.69 Energy NUCLEAR REGULATORY..., systems and components for nuclear power reactors. (a) Definitions. Risk-Informed Safety Class...
Code of Federal Regulations, 2014 CFR
2014-01-01
... whose expertise includes, at a minimum, PRA, safety analysis, plant operation, design engineering, and..., systems and components for nuclear power reactors. 50.69 Section 50.69 Energy NUCLEAR REGULATORY..., systems and components for nuclear power reactors. (a) Definitions. Risk-Informed Safety Class...
A structural design decomposition method utilizing substructuring
NASA Technical Reports Server (NTRS)
Scotti, Stephen J.
1994-01-01
A new method of design decomposition for structural analysis and optimization is described. For this method, the structure is divided into substructures where each substructure has its structural response described by a structural-response subproblem, and its structural sizing determined from a structural-sizing subproblem. The structural responses of substructures that have rigid body modes when separated from the remainder of the structure are further decomposed into displacements that have no rigid body components, and a set of rigid body modes. The structural-response subproblems are linked together through forces determined within a structural-sizing coordination subproblem which also determines the magnitude of any rigid body displacements. Structural-sizing subproblems having constraints local to the substructures are linked together through penalty terms that are determined by a structural-sizing coordination subproblem. All the substructure structural-response subproblems are totally decoupled from each other, as are all the substructure structural-sizing subproblems, thus there is significant potential for use of parallel solution methods for these subproblems.
Method for designing gas tag compositions
Gross, K.C.
1995-04-11
For use in the manufacture of gas tags such as employed in a nuclear reactor gas tagging failure detection system, a method for designing gas tagging compositions utilizes an analytical approach wherein the final composition of a first canister of tag gas as measured by a mass spectrometer is designated as node No. 1. Lattice locations of tag nodes in multi-dimensional space are then used in calculating the compositions of a node No. 2 and each subsequent node so as to maximize the distance of each node from any combination of tag components which might be indistinguishable from another tag composition in a reactor fuel assembly. Alternatively, the measured compositions of tag gas numbers 1 and 2 may be used to fix the locations of nodes 1 and 2, with the locations of nodes 3-N then calculated for optimum tag gas composition. A single sphere defining the lattice locations of the tag nodes may be used to define approximately 20 tag nodes, while concentric spheres can extend the number of tag nodes to several hundred. 5 figures.
Method for designing gas tag compositions
Gross, Kenny C.
1995-01-01
For use in the manufacture of gas tags such as employed in a nuclear reactor gas tagging failure detection system, a method for designing gas tagging compositions utilizes an analytical approach wherein the final composition of a first canister of tag gas as measured by a mass spectrometer is designated as node #1. Lattice locations of tag nodes in multi-dimensional space are then used in calculating the compositions of a node #2 and each subsequent node so as to maximize the distance of each node from any combination of tag components which might be indistinguishable from another tag composition in a reactor fuel assembly. Alternatively, the measured compositions of tag gas numbers 1 and 2 may be used to fix the locations of nodes 1 and 2, with the locations of nodes 3-N then calculated for optimum tag gas composition. A single sphere defining the lattice locations of the tag nodes may be used to define approximately 20 tag nodes, while concentric spheres can extend the number of tag nodes to several hundred.
Research and Design of Rootkit Detection Method
NASA Astrophysics Data System (ADS)
Liu, Leian; Yin, Zuanxing; Shen, Yuli; Lin, Haitao; Wang, Hongjiang
Rootkit is one of the most important issues of network communication systems, which is related to the security and privacy of Internet users. Because of the existence of the back door of the operating system, a hacker can use rootkit to attack and invade other people's computers and thus he can capture passwords and message traffic to and from these computers easily. With the development of the rootkit technology, its applications are more and more extensive and it becomes increasingly difficult to detect it. In addition, for various reasons such as trade secrets, being difficult to be developed, and so on, the rootkit detection technology information and effective tools are still relatively scarce. In this paper, based on the in-depth analysis of the rootkit detection technology, a new kind of the rootkit detection structure is designed and a new method (software), X-Anti, is proposed. Test results show that software designed based on structure proposed is much more efficient than any other rootkit detection software.
Kaphingst, Kimberly A.; Stafford, Jewel D.; McGowan, Lucy D’Agostino; Seo, Joann; Lachance, Christina R.; Goodman, Melody S.
2015-01-01
Objective Few studies have examined how individuals respond to genomic risk information for common, chronic diseases. This randomized study examined differences in responses by type of genomic information [genetic test/family history] and disease condition [diabetes/heart disease] and by race/ethnicity in a medically underserved population. Methods 1057 English-speaking adults completed a survey containing one of four vignettes (two-by-two randomized design). Differences in dependent variables (i.e., interest in receiving genomic assessment, discussing with doctor or family, changing health habits) by experimental condition and race/ethnicity were examined using chi-squared tests and multivariable regression analysis. Results No significant differences were found in dependent variables by type of genomic information or disease condition. In multivariable models, Hispanics were more interested in receiving a genomic assessment than Whites (OR=1.93; p<0.0001); respondents with marginal (OR=1.54; p=0.005) or limited (OR=1.85; p=0.009) health literacy had greater interest than those with adequate health literacy. Blacks (OR=1.78; p=0.001) and Hispanics (OR=1.85; p=0.001) had greater interest in discussing information with family than Whites. Non-Hispanic Blacks (OR=1.45; p=0.04) had greater interest in discussing genomic information with a doctor than Whites. Blacks (β= −0.41; p<0.001) and Hispanics (β= −0.25; p=0.033) intended to change fewer health habits than Whites; health literacy was negatively associated with number of health habits participants intended to change. Conclusions Findings suggest that race/ethnicity may affect responses to genomic risk information. Additional research could examine how cognitive representations of this information differ across racial/ethnic groups. Health literacy is also critical to consider in developing approaches to communicating genomic information. PMID:25622080
A rainfall design method for spatial flood risk assessment: considering multiple flood sources
NASA Astrophysics Data System (ADS)
Jiang, X.; Tatano, H.
2015-08-01
Information about the spatial distribution of flood risk is important for integrated urban flood risk management. Focusing on urban areas, spatial flood risk assessment must reflect all risk information derived from multiple flood sources: rivers, drainage, coastal flooding etc. that may affect the area. However, conventional flood risk assessment deals with each flood source independently, which leads to an underestimation of flood risk in the floodplain. Even in floodplains that have no risk from coastal flooding, flooding from river channels and inundation caused by insufficient drainage capacity should be considered simultaneously. For integrated flood risk management, it is necessary to establish a methodology to estimate flood risk distribution across a floodplain. In this paper, a rainfall design method for spatial flood risk assessment, which considers the joint effects of multiple flood sources, is proposed. The concept of critical rainfall duration determined by the concentration time of flooding is introduced to connect response characteristics of different flood sources with rainfall. A copula method is then adopted to capture the correlation of rainfall amount with different critical rainfall durations. Rainfall events are designed taking advantage of the copula structure of correlation and marginal distribution of rainfall amounts within different critical rainfall durations. A case study in the Otsu River Basin, Osaka prefecture, Japan was conducted to demonstrate this methodology.
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…
Translating Vision into Design: A Method for Conceptual Design Development
NASA Technical Reports Server (NTRS)
Carpenter, Joyce E.
2003-01-01
One of the most challenging tasks for engineers is the definition of design solutions that will satisfy high-level strategic visions and objectives. Even more challenging is the need to demonstrate how a particular design solution supports the high-level vision. This paper describes a process and set of system engineering tools that have been used at the Johnson Space Center to analyze and decompose high-level objectives for future human missions into design requirements that can be used to develop alternative concepts for vehicles, habitats, and other systems. Analysis and design studies of alternative concepts and approaches are used to develop recommendations for strategic investments in research and technology that support the NASA Integrated Space Plan. In addition to a description of system engineering tools, this paper includes a discussion of collaborative design practices for human exploration mission architecture studies used at the Johnson Space Center.
An inverse design method for 2D airfoil
NASA Astrophysics Data System (ADS)
Liang, Zhi-Yong; Cui, Peng; Zhang, Gen-Bao
2010-03-01
The computational method for aerodynamic design of aircraft is applied more universally than before, in which the design of an airfoil is a hot problem. The forward problem is discussed by most relative papers, but inverse method is more useful in practical designs. In this paper, the inverse design of 2D airfoil was investigated. A finite element method based on the variational principle was used for carrying out. Through the simulation, it was shown that the method was fit for the design.
B. Bishop; et al
2005-03-30
This study indicates that risk-informed methods can be used to significantly relax the current ASME and NRC Appendix G requirements while still maintaining satisfactory levels of reactor vessel structural integrity. This relaxation in Appendix G requirements directly translates into significant improvements in operational flexibility.
Using Software Design Methods in CALL
ERIC Educational Resources Information Center
Ward, Monica
2006-01-01
The phrase "software design" is not one that arouses the interest of many CALL practitioners, particularly those from a humanities background. However, software design essentials are simply logical ways of going about designing a system. The fundamentals include modularity, anticipation of change, generality and an incremental approach. While CALL…
Global optimization methods for engineering design
NASA Technical Reports Server (NTRS)
Arora, Jasbir S.
1990-01-01
The problem is to find a global minimum for the Problem P. Necessary and sufficient conditions are available for local optimality. However, global solution can be assured only under the assumption of convexity of the problem. If the constraint set S is compact and the cost function is continuous on it, existence of a global minimum is guaranteed. However, in view of the fact that no global optimality conditions are available, a global solution can be found only by an exhaustive search to satisfy Inequality. The exhaustive search can be organized in such a way that the entire design space need not be searched for the solution. This way the computational burden is reduced somewhat. It is concluded that zooming algorithm for global optimizations appears to be a good alternative to stochastic methods. More testing is needed; a general, robust, and efficient local minimizer is required. IDESIGN was used in all numerical calculations which is based on a sequential quadratic programming algorithm, and since feasible set keeps on shrinking, a good algorithm to find an initial feasible point is required. Such algorithms need to be developed and evaluated.
An Efficient Inverse Aerodynamic Design Method For Subsonic Flows
NASA Technical Reports Server (NTRS)
Milholen, William E., II
2000-01-01
Computational Fluid Dynamics based design methods are maturing to the point that they are beginning to be used in the aircraft design process. Many design methods however have demonstrated deficiencies in the leading edge region of airfoil sections. The objective of the present research is to develop an efficient inverse design method which is valid in the leading edge region. The new design method is a streamline curvature method, and a new technique is presented for modeling the variation of the streamline curvature normal to the surface. The new design method allows the surface coordinates to move normal to the surface, and has been incorporated into the Constrained Direct Iterative Surface Curvature (CDISC) design method. The accuracy and efficiency of the design method is demonstrated using both two-dimensional and three-dimensional design cases.
Design optimization method for Francis turbine
NASA Astrophysics Data System (ADS)
Kawajiri, H.; Enomoto, Y.; Kurosawa, S.
2014-03-01
This paper presents a design optimization system coupled CFD. Optimization algorithm of the system employs particle swarm optimization (PSO). Blade shape design is carried out in one kind of NURBS curve defined by a series of control points. The system was applied for designing the stationary vanes and the runner of higher specific speed francis turbine. As the first step, single objective optimization was performed on stay vane profile, and second step was multi-objective optimization for runner in wide operating range. As a result, it was confirmed that the design system is useful for developing of hydro turbine.
Alternative methods for the design of jet engine control systems
NASA Technical Reports Server (NTRS)
Sain, M. K.; Leake, R. J.; Basso, R.; Gejji, R.; Maloney, A.; Seshadri, V.
1976-01-01
Various alternatives to linear quadratic design methods for jet engine control systems are discussed. The main alternatives are classified into two broad categories: nonlinear global mathematical programming methods and linear local multivariable frequency domain methods. Specific studies within these categories include model reduction, the eigenvalue locus method, the inverse Nyquist method, polynomial design, dynamic programming, and conjugate gradient approaches.
Demystifying Mixed Methods Research Design: A Review of the Literature
ERIC Educational Resources Information Center
Caruth, Gail D.
2013-01-01
Mixed methods research evolved in response to the observed limitations of both quantitative and qualitative designs and is a more complex method. The purpose of this paper was to examine mixed methods research in an attempt to demystify the design thereby allowing those less familiar with its design an opportunity to utilize it in future research.…
Airfoil design method using the Navier-Stokes equations
NASA Technical Reports Server (NTRS)
Malone, J. B.; Narramore, J. C.; Sankar, L. N.
1991-01-01
An airfoil design procedure is described that was incorporated into an existing 2-D Navier-Stokes airfoil analysis method. The resulting design method, an iterative procedure based on a residual-correction algorithm, permits the automated design of airfoil sections with prescribed surface pressure distributions. The inverse design method and the technique used to specify target pressure distributions are described. It presents several example problems to demonstrate application of the design procedure. It shows that this inverse design method develops useful airfoil configurations with a reasonable expenditure of computer resources.
A Method of Integrated Description of Design Information for Reusability
NASA Astrophysics Data System (ADS)
Tsumaya, Akira; Nagae, Masao; Wakamatsu, Hidefumi; Shirase, Keiichi; Arai, Eiji
Much of product design is executed concurrently these days. For such concurrent design, the method which can share and ueuse varioud kind of design information among designers is needed. However, complete understanding of the design information among designers have been a difficult issue. In this paper, design process model with use of designers’ intention is proposed. A method to combine the design process information and the design object information is also proposed. We introduce how to describe designers’ intention by providing some databases. Keyword Database consists of ontological data related to design object/activities. Designers select suitable keyword(s) from Keyword Database and explain the reason/ideas for their design activities by the description with use of keyword(s). We also developed the integration design information management system architecture by using a method of integrated description with designers’ intension. This system realizes connections between the information related to design process and that related to design object through designers’ intention. Designers can communicate with each other to understand how others make decision in design through that. Designers also can re-use both design process information data and design object information data through detabase management sub-system.
Curtis Smith; David Schwieder; Cherie Phelan; Anh Bui; Paul Bayless
2012-08-01
Safety is central to the design, licensing, operation, and economics of Nuclear Power Plants (NPPs). Consequently, the ability to better characterize and quantify safety margin holds the key to improved decision making about LWR design, operation, and plant life extension. A systematic approach to characterization of safety margins and the subsequent margins management options represents a vital input to the licensee and regulatory analysis and decision making that will be involved. The purpose of the RISMC Pathway R&D is to support plant decisions for risk-informed margins management with the aim to improve economics, reliability, and sustain safety of current NPPs. Goals of the RISMC Pathway are twofold: (1) Develop and demonstrate a risk-assessment method coupled to safety margin quantification that can be used by NPP decision makers as part of their margin recovery strategies. (2) Create an advanced “RISMC toolkit” that enables more accurate representation of NPP safety margin. This report describes the RISMC methodology demonstration where the Advanced Test Reactor (ATR) was used as a test-bed for purposes of determining safety margins. As part of the demonstration, we describe how both the thermal-hydraulics and probabilistic safety calculations are integrated and used to quantify margin management strategies.
JASMINE design and method of data reduction
NASA Astrophysics Data System (ADS)
Yamada, Yoshiyuki; Gouda, Naoteru; Yano, Taihei; Kobayashi, Yukiyasu; Niwa, Yoshito
2008-07-01
Japan Astrometry Satellite Mission for Infrared Exploration (JASMINE) aims to construct a map of the Galactic bulge with 10 μ arc sec accuracy. We use z-band CCD for avoiding dust absorption, and observe about 10 × 20 degrees area around the Galactic bulge region. Because the stellar density is very high, each FOVs can be combined with high accuracy. With 5 years observation, we will construct 10 μ arc sec accurate map. In this poster, I will show the observation strategy, design of JASMINE hardware, reduction scheme, and error budget. We also construct simulation software named JASMINE Simulator. We also show the simulation results and design of software.
Lithography aware overlay metrology target design method
NASA Astrophysics Data System (ADS)
Lee, Myungjun; Smith, Mark D.; Lee, Joonseuk; Jung, Mirim; Lee, Honggoo; Kim, Youngsik; Han, Sangjun; Adel, Michael E.; Lee, Kangsan; Lee, Dohwa; Choi, Dongsub; Liu, Zephyr; Itzkovich, Tal; Levinski, Vladimir; Levy, Ady
2016-03-01
We present a metrology target design (MTD) framework based on co-optimizing lithography and metrology performance. The overlay metrology performance is strongly related to the target design and optimizing the target under different process variations in a high NA optical lithography tool and measurement conditions in a metrology tool becomes critical for sub-20nm nodes. The lithography performance can be quantified by device matching and printability metrics, while accuracy and precision metrics are used to quantify the metrology performance. Based on using these metrics, we demonstrate how the optimized target can improve target printability while maintaining the good metrology performance for rotated dipole illumination used for printing a sub-100nm diagonal feature in a memory active layer. The remaining challenges and the existing tradeoff between metrology and lithography performance are explored with the metrology target designer's perspective. The proposed target design framework is completely general and can be used to optimize targets for different lithography conditions. The results from our analysis are both physically sensible and in good agreement with experimental results.
Probabilistic Methods for Structural Design and Reliability
NASA Technical Reports Server (NTRS)
Chamis, Christos C.; Whitlow, Woodrow, Jr. (Technical Monitor)
2002-01-01
This report describes a formal method to quantify structural damage tolerance and reliability in the presence of a multitude of uncertainties in turbine engine components. The method is based at the material behavior level where primitive variables with their respective scatter ranges are used to describe behavior. Computational simulation is then used to propagate the uncertainties to the structural scale where damage tolerance and reliability are usually specified. Several sample cases are described to illustrate the effectiveness, versatility, and maturity of the method. Typical results from this method demonstrate, that it is mature and that it can be used to probabilistically evaluate turbine engine structural components. It may be inferred from the results that the method is suitable for probabilistically predicting the remaining life in aging or in deteriorating structures, for making strategic projections and plans, and for achieving better, cheaper, faster products that give competitive advantages in world markets.
A comparison of digital flight control design methods
NASA Technical Reports Server (NTRS)
Powell, J. D.; Parsons, E.; Tashker, M. G.
1976-01-01
Many variations in design methods for aircraft digital flight control have been proposed in the literature. In general, the methods fall into two categories: those where the design is done in the continuous domain (or s-plane), and those where the design is done in the discrete domain (or z-plane). This paper evaluates several variations of each category and compares them for various flight control modes of the Langley TCV Boeing 737 aircraft. Design method fidelity is evaluated by examining closed loop root movement and the frequency response of the discretely controlled continuous aircraft. It was found that all methods provided acceptable performance for sample rates greater than 10 cps except the 'uncompensated s-plane design' method which was acceptable above 20 cps. A design procedure based on optimal control methods was proposed that provided the best fidelity at very slow sample rates and required no design iterations for changing sample rates.
Soft Computing Methods in Design of Superalloys
NASA Technical Reports Server (NTRS)
Cios, K. J.; Berke, L.; Vary, A.; Sharma, S.
1996-01-01
Soft computing techniques of neural networks and genetic algorithms are used in the design of superalloys. The cyclic oxidation attack parameter K(sub a), generated from tests at NASA Lewis Research Center, is modelled as a function of the superalloy chemistry and test temperature using a neural network. This model is then used in conjunction with a genetic algorithm to obtain an optimized superalloy composition resulting in low K(sub a) values.
An overview of very high level software design methods
NASA Technical Reports Server (NTRS)
Asdjodi, Maryam; Hooper, James W.
1988-01-01
Very High Level design methods emphasize automatic transfer of requirements to formal design specifications, and/or may concentrate on automatic transformation of formal design specifications that include some semantic information of the system into machine executable form. Very high level design methods range from general domain independent methods to approaches implementable for specific applications or domains. Applying AI techniques, abstract programming methods, domain heuristics, software engineering tools, library-based programming and other methods different approaches for higher level software design are being developed. Though one finds that a given approach does not always fall exactly in any specific class, this paper provides a classification for very high level design methods including examples for each class. These methods are analyzed and compared based on their basic approaches, strengths and feasibility for future expansion toward automatic development of software systems.
The Triton: Design concepts and methods
NASA Technical Reports Server (NTRS)
Meholic, Greg; Singer, Michael; Vanryn, Percy; Brown, Rhonda; Tella, Gustavo; Harvey, Bob
1992-01-01
During the design of the C & P Aerospace Triton, a few problems were encountered that necessitated changes in the configuration. After the initial concept phase, the aspect ratio was increased from 7 to 7.6 to produce a greater lift to drag ratio (L/D = 13) which satisfied the horsepower requirements (118 hp using the Lycoming O-235 engine). The initial concept had a wing planform area of 134 sq. ft. Detailed wing sizing analysis enlarged the planform area to 150 sq. ft., without changing its layout or location. The most significant changes, however, were made just prior to inboard profile design. The fuselage external diameter was reduced from 54 to 50 inches to reduce drag to meet the desired cruise speed of 120 knots. Also, the nose was extended 6 inches to accommodate landing gear placement. Without the extension, the nosewheel received an unacceptable percentage (25 percent) of the landing weight. The final change in the configuration was made in accordance with the stability and control analysis. In order to reduce the static margin from 20 to 13 percent, the horizontal tail area was reduced from 32.02 to 25.0 sq. ft. The Triton meets all the specifications set forth in the design criteria. If time permitted another iteration of the calculations, two significant changes would be made. The vertical stabilizer area would be reduced to decrease the aircraft lateral stability slope since the current value was too high in relation to the directional stability slope. Also, the aileron size would be decreased to reduce the roll rate below the current 106 deg/second. Doing so would allow greater flap area (increasing CL(sub max)) and thus reduce the overall wing area. C & P would also recalculate the horsepower and drag values to further validate the 120 knot cruising speed.
NASA Astrophysics Data System (ADS)
Kucharski, John; Tkach, Mark; Olszewski, Jennifer; Chaudhry, Rabia; Mendoza, Guillermo
2016-04-01
This presentation demonstrates the application of Climate Risk Informed Decision Analysis (CRIDA) at Zambia's principal water treatment facility, The Iolanda Water Treatment Plant. The water treatment plant is prone to unacceptable failures during periods of low hydropower production at the Kafue Gorge Dam Hydroelectric Power Plant. The case study explores approaches of increasing the water treatment plant's ability to deliver acceptable levels of service under the range of current and potential future climate states. The objective of the study is to investigate alternative investments to build system resilience that might have been informed by the CRIDA process, and to evaluate the extra resource requirements by a bilateral donor agency to implement the CRIDA process. The case study begins with an assessment of the water treatment plant's vulnerability to climate change. It does so by following general principals described in "Confronting Climate Uncertainty in Water Resource Planning and Project Design: the Decision Tree Framework". By utilizing relatively simple bootstrapping methods a range of possible future climate states is generated while avoiding the use of more complex and costly downscaling methodologies; that are beyond the budget and technical capacity of many teams. The resulting climate vulnerabilities and uncertainty in the climate states that produce them are analyzed as part of a "Level of Concern" analysis. CRIDA principals are then applied to this Level of Concern analysis in order to arrive at a set of actionable water management decisions. The principal goals of water resource management is to transform variable, uncertain hydrology into dependable services (e.g. water supply, flood risk reduction, ecosystem benefits, hydropower production, etc…). Traditional approaches to climate adaptation require the generation of predicted future climate states but do little guide decision makers how this information should impact decision making. In
A survey on methods of design features identification
NASA Astrophysics Data System (ADS)
Grabowik, C.; Kalinowski, K.; Paprocka, I.; Kempa, W.
2015-11-01
It is widely accepted that design features are one of the most attractive integration method of most fields of engineering activities such as a design modelling, process planning or production scheduling. One of the most important tasks which are realized in the integration process of design and planning functions is a design translation meant as design data mapping into data which are important from process planning needs point of view, it is manufacturing data. A design geometrical shape translation process can be realized with application one of the following strategies: (i) designing with previously prepared design features library also known as DBF method it is design by feature, (ii) interactive design features recognition IFR, (iii) automatic design features recognition AFR. In case of the DBF method design geometrical shape is created with design features. There are two basic approaches for design modelling in DBF method it is classic in which a part design is modelled from beginning to end with application design features previously stored in a design features data base and hybrid where part is partially created with standard predefined CAD system tools and the rest with suitable design features. Automatic feature recognition consist in an autonomic searching of a product model represented with a specific design representation method in order to find those model features which might be potentially recognized as design features, manufacturing features, etc. This approach needs the searching algorithm to be prepared. The searching algorithm should allow carrying on the whole recognition process without a user supervision. Currently there are lots of AFR methods. These methods need the product model to be represented with B-Rep representation most often, CSG rarely, wireframe very rarely. In the IFR method potential features are being recognized by a user. This process is most often realized by a user who points out those surfaces which seem to belong to a
Defining resilience within a risk-informed assessment framework
Coles, Garill A.; Unwin, Stephen D.; Holter, Gregory M.; Bass, Robert B.; Dagle, Jeffery E.
2011-08-01
The concept of resilience is the subject of considerable discussion in academic, business, and governmental circles. The United States Department of Homeland Security for one has emphasised the need to consider resilience in safeguarding critical infrastructure and key resources. The concept of resilience is complex, multidimensional, and defined differently by different stakeholders. The authors contend that there is a benefit in moving from discussing resilience as an abstraction to defining resilience as a measurable characteristic of a system. This paper proposes defining resilience measures using elements of a traditional risk assessment framework to help clarify the concept of resilience and as a way to provide non-traditional risk information. The authors show various, diverse dimensions of resilience can be quantitatively defined in a common risk assessment framework based on the concept of loss of service. This allows the comparison of options for improving the resilience of infrastructure and presents a means to perform cost-benefit analysis. This paper discusses definitions and key aspects of resilience, presents equations for the risk of loss of infrastructure function that incorporate four key aspects of resilience that could prevent or mitigate that loss, describes proposed resilience factor definitions based on those risk impacts, and provides an example that illustrates how resilience factors would be calculated using a hypothetical scenario.
Background risk information to assist in risk management decision making
Hammonds, J.S.; Hoffman, F.O.; White, R.K.; Miller, D.B.
1992-10-01
The evaluation of the need for remedial activities at hazardous waste sites requires quantification of risks of adverse health effects to humans and the ecosystem resulting from the presence of chemical and radioactive substances at these sites. The health risks from exposure to these substances are in addition to risks encountered because of the virtually unavoidable exposure to naturally occurring chemicals and radioactive materials that are present in air, water, soil, building materials, and food products. To provide a frame of reference for interpreting risks quantified for hazardous waste sites, it is useful to identify the relative magnitude of risks of both a voluntary and involuntary nature that are ubiquitous throughout east Tennessee. In addition to discussing risks from the ubiquitous presence of background carcinogens in the east Tennessee environment, this report also presents risks resulting from common, everyday activities. Such information should, not be used to discount or trivialize risks from hazardous waste contamination, but rather, to create a sensitivity to general risk issues, thus providing a context for better interpretation of risk information.
Design Methods and Optimization for Morphing Aircraft
NASA Technical Reports Server (NTRS)
Crossley, William A.
2005-01-01
This report provides a summary of accomplishments made during this research effort. The major accomplishments are in three areas. The first is the use of a multiobjective optimization strategy to help identify potential morphing features that uses an existing aircraft sizing code to predict the weight, size and performance of several fixed-geometry aircraft that are Pareto-optimal based upon on two competing aircraft performance objectives. The second area has been titled morphing as an independent variable and formulates the sizing of a morphing aircraft as an optimization problem in which the amount of geometric morphing for various aircraft parameters are included as design variables. This second effort consumed most of the overall effort on the project. The third area involved a more detailed sizing study of a commercial transport aircraft that would incorporate a morphing wing to possibly enable transatlantic point-to-point passenger service.
A flexible layout design method for passive micromixers.
Deng, Yongbo; Liu, Zhenyu; Zhang, Ping; Liu, Yongshun; Gao, Qingyong; Wu, Yihui
2012-10-01
This paper discusses a flexible layout design method of passive micromixers based on the topology optimization of fluidic flows. Being different from the trial and error method, this method obtains the detailed layout of a passive micromixer according to the desired mixing performance by solving a topology optimization problem. Therefore, the dependence on the experience of the designer is weaken, when this method is used to design a passive micromixer with acceptable mixing performance. Several design disciplines for the passive micromixers are considered to demonstrate the flexibility of the layout design method for passive micromixers. These design disciplines include the approximation of the real 3D micromixer, the manufacturing feasibility, the spacial periodic design, and effects of the Péclet number and Reynolds number on the designs obtained by this layout design method. The capability of this design method is validated by several comparisons performed between the obtained layouts and the optimized designs in the recently published literatures, where the values of the mixing measurement is improved up to 40.4% for one cycle of the micromixer. PMID:22736305
NASA Technical Reports Server (NTRS)
Patnaik, Surya N.; Pai, Shantaram S.; Coroneos, Rula M.
2010-01-01
Structural design generated by traditional method, optimization method and the stochastic design concept are compared. In the traditional method, the constraints are manipulated to obtain the design and weight is back calculated. In design optimization, the weight of a structure becomes the merit function with constraints imposed on failure modes and an optimization algorithm is used to generate the solution. Stochastic design concept accounts for uncertainties in loads, material properties, and other parameters and solution is obtained by solving a design optimization problem for a specified reliability. Acceptable solutions were produced by all the three methods. The variation in the weight calculated by the methods was modest. Some variation was noticed in designs calculated by the methods. The variation may be attributed to structural indeterminacy. It is prudent to develop design by all three methods prior to its fabrication. The traditional design method can be improved when the simplified sensitivities of the behavior constraint is used. Such sensitivity can reduce design calculations and may have a potential to unify the traditional and optimization methods. Weight versus reliabilitytraced out an inverted-S-shaped graph. The center of the graph corresponded to mean valued design. A heavy design with weight approaching infinity could be produced for a near-zero rate of failure. Weight can be reduced to a small value for a most failure-prone design. Probabilistic modeling of load and material properties remained a challenge.
Analytical techniques for instrument design - matrix methods
Robinson, R.A.
1997-09-01
We take the traditional Cooper-Nathans approach, as has been applied for many years for steady-state triple-axis spectrometers, and consider its generalisation to other inelastic scattering spectrometers. This involves a number of simple manipulations of exponentials of quadratic forms. In particular, we discuss a toolbox of matrix manipulations that can be performed on the 6- dimensional Cooper-Nathans matrix: diagonalisation (Moller-Nielsen method), coordinate changes e.g. from ({Delta}k{sub I},{Delta}k{sub F} to {Delta}E, {Delta}Q & 2 dummy variables), integration of one or more variables (e.g. over such dummy variables), integration subject to linear constraints (e.g. Bragg`s Law for analysers), inversion to give the variance-covariance matrix, and so on. We show how these tools can be combined to solve a number of important problems, within the narrow-band limit and the gaussian approximation. We will argue that a generalised program that can handle multiple different spectrometers could (and should) be written in parallel to the Monte-Carlo packages that are becoming available. We will also discuss the complementarity between detailed Monte-Carlo calculations and the approach presented here. In particular, Monte-Carlo methods traditionally simulate the real experiment as performed in practice, given a model scattering law, while the Cooper-Nathans method asks the inverse question: given that a neutron turns up in a particular spectrometer configuration (e.g. angle and time of flight), what is the probability distribution of possible scattering events at the sample? The Monte-Carlo approach could be applied in the same spirit to this question.
Design Method for Single-Blade Centrifugal Pump Impeller
NASA Astrophysics Data System (ADS)
Nishi, Yasuyuki; Fujiwara, Ryota; Fukutomi, Junichiro
The sewage pumps are demanded a high pump efficiency and a performance in passing foreign bodies. Therefore, the impeller used by these usages requires the large passed particle size (minimum particle size in the pump). However, because conventional design method of pump impeller results in small impeller exit width, it is difficult to be applied to the design of single-blade centrifugal pump impeller which is used as a sewage pump. This paper proposes a design method for single-blade centrifugal pump impeller. As a result, the head curve of the impeller designed by the proposed design method satisfied design specifications, and pump efficiency was over 62% more than conventional single-blade centrifugal pump impeller. By comparing design values with CFD analysis values, the suction velocity ratio of the design parameter agreed well with each other, but the relative velocity ratio did not agree due to the influence of the backflow of the impeller entrance.
Methods for very high temperature design
Blass, J.J.; Corum, J.M.; Chang, S.J.
1989-01-01
Design rules and procedures for high-temperature, gas-cooled reactor components are being formulated as an ASME Boiler and Pressure Vessel Code Case. A draft of the Case, patterned after Code Case N-47, and limited to Inconel 617 and temperatures of 982/degree/C (1800/degree/F) or less, will be completed in 1989 for consideration by relevant Code committees. The purpose of this paper is to provide a synopsis of the significant differences between the draft Case and N-47, and to provide more complete accounts of the development of allowable stress and stress rupture values and the development of isochronous stress vs strain curves, in both of which Oak Ridge National Laboratory (ORNL) played a principal role. The isochronous curves, which represent average behavior for many heats of Inconel 617, were based in part on a unified constitutive model developed at ORNL. Details are also provided of this model of inelastic deformation behavior, which does not distinguish between rate-dependent plasticity and time-dependent creep, along with comparisons between calculated and observed results of tests conducted on a typical heat of Inconel 617 by the General Electric Company for the Department of Energy. 4 refs., 15 figs., 1 tab.
Risk-Informing Safety Reviews for Non-Reactor Nuclear Facilities
Mubayi, V.; Azarm, A.; Yue, M.; Mukaddam, W.; Good, G.; Gonzalez, F.; Bari, R.A.
2011-03-13
This paper describes a methodology used to model potential accidents in fuel cycle facilities that employ chemical processes to separate and purify nuclear materials. The methodology is illustrated with an example that uses event and fault trees to estimate the frequency of a specific energetic reaction that can occur in nuclear material processing facilities. The methodology used probabilistic risk assessment (PRA)-related tools as well as information about the chemical reaction characteristics, information on plant design and operational features, and generic data about component failure rates and human error rates. The accident frequency estimates for the specific reaction help to risk-inform the safety review process and assess compliance with regulatory requirements.
Analyses in support of risk-informed natural gas vehicle maintenance facility codes and standards :
Ekoto, Isaac W.; Blaylock, Myra L.; LaFleur, Angela Christine; LaChance, Jeffrey L.; Horne, Douglas B.
2014-03-01
Safety standards development for maintenance facilities of liquid and compressed gas fueled large-scale vehicles is required to ensure proper facility design and operation envelopes. Standard development organizations are utilizing risk-informed concepts to develop natural gas vehicle (NGV) codes and standards so that maintenance facilities meet acceptable risk levels. The present report summarizes Phase I work for existing NGV repair facility code requirements and highlights inconsistencies that need quantitative analysis into their effectiveness. A Hazardous and Operability study was performed to identify key scenarios of interest. Finally, scenario analyses were performed using detailed simulations and modeling to estimate the overpressure hazards from HAZOP defined scenarios. The results from Phase I will be used to identify significant risk contributors at NGV maintenance facilities, and are expected to form the basis for follow-on quantitative risk analysis work to address specific code requirements and identify effective accident prevention and mitigation strategies.
Analytical techniques for instrument design -- Matrix methods
Robinson, R.A.
1997-12-31
The authors take the traditional Cooper-Nathans approach, as has been applied for many years for steady-state triple-axis spectrometers, and consider its generalization to other inelastic scattering spectrometers. This involves a number of simple manipulations of exponentials of quadratic forms. In particular, they discuss a toolbox of matrix manipulations that can be performed on the 6-dimensional Cooper-Nathans matrix. They show how these tools can be combined to solve a number of important problems, within the narrow-band limit and the gaussian approximation. They will argue that a generalized program that can handle multiple different spectrometers could (and should) be written in parallel to the Monte-Carlo packages that are becoming available. They also discuss the complementarity between detailed Monte-Carlo calculations and the approach presented here. In particular, Monte-Carlo methods traditionally simulate the real experiment as performed in practice, given a model scattering law, while the Cooper-Nathans method asks the inverse question: given that a neutron turns up in a particular spectrometer configuration (e.g. angle and time of flight), what is the probability distribution of possible scattering events at the sample? The Monte-Carlo approach could be applied in the same spirit to this question.
Ng, Annie W Y; Siu, Kin Wai Michael; Chan, Chetwyn C H
2013-01-01
This study investigated the practices and attitudes of novice designers toward user involvement in public symbol design at the conceptual design stage, i.e. the stereotype production method. Differences between male and female novice designers were examined. Forty-eight novice designers (24 male, 24 female) were asked to design public symbol referents based on suggestions made by a group of users in a previous study and provide feedback with regard to the design process. The novice designers were receptive to the adoption of user suggestions in the conception of the design, but tended to modify the pictorial representations generated by the users to varying extents. It is also significant that the male and female novice designers appeared to emphasize different aspects of user suggestions, and the female novice designers were more positive toward these suggestions than their male counterparts. The findings should aid the optimization of the stereotype production method for user-involved symbol design. PMID:22632980
HEALTHY study rationale, design and methods
2009-01-01
The HEALTHY primary prevention trial was designed and implemented in response to the growing numbers of children and adolescents being diagnosed with type 2 diabetes. The objective was to moderate risk factors for type 2 diabetes. Modifiable risk factors measured were indicators of adiposity and glycemic dysregulation: body mass index ≥85th percentile, fasting glucose ≥5.55 mmol l-1 (100 mg per 100 ml) and fasting insulin ≥180 pmol l-1 (30 μU ml-1). A series of pilot studies established the feasibility of performing data collection procedures and tested the development of an intervention consisting of four integrated components: (1) changes in the quantity and nutritional quality of food and beverage offerings throughout the total school food environment; (2) physical education class lesson plans and accompanying equipment to increase both participation and number of minutes spent in moderate-to-vigorous physical activity; (3) brief classroom activities and family outreach vehicles to increase knowledge, enhance decision-making skills and support and reinforce youth in accomplishing goals; and (4) communications and social marketing strategies to enhance and promote changes through messages, images, events and activities. Expert study staff provided training, assistance, materials and guidance for school faculty and staff to implement the intervention components. A cohort of students were enrolled in sixth grade and followed to end of eighth grade. They attended a health screening data collection at baseline and end of study that involved measurement of height, weight, blood pressure, waist circumference and a fasting blood draw. Height and weight were also collected at the end of the seventh grade. The study was conducted in 42 middle schools, six at each of seven locations across the country, with 21 schools randomized to receive the intervention and 21 to act as controls (data collection activities only). Middle school was the unit of sample size and
Experimental design for improved ceramic processing, emphasizing the Taguchi Method
Weiser, M.W. . Mechanical Engineering Dept.); Fong, K.B. )
1993-12-01
Ceramic processing often requires substantial experimentation to produce acceptable product quality and performance. This is a consequence of ceramic processes depending upon a multitude of factors, some of which can be controlled and others that are beyond the control of the manufacturer. Statistical design of experiments is a procedure that allows quick, economical, and accurate evaluation of processes and products that depend upon several variables. Designed experiments are sets of tests in which the variables are adjusted methodically. A well-designed experiment yields unambiguous results at minimal cost. A poorly designed experiment may reveal little information of value even with complex analysis, wasting valuable time and resources. This article will review the most common experimental designs. This will include both nonstatistical designs and the much more powerful statistical experimental designs. The Taguchi Method developed by Grenichi Taguchi will be discussed in some detail. The Taguchi method, based upon fractional factorial experiments, is a powerful tool for optimizing product and process performance.
A new interval optimization method considering tolerance design
NASA Astrophysics Data System (ADS)
Jiang, C.; Xie, H. C.; Zhang, Z. G.; Han, X.
2015-12-01
This study considers the design variable uncertainty in the actual manufacturing process for a product or structure and proposes a new interval optimization method based on tolerance design, which can provide not only an optimal design but also the allowable maximal manufacturing errors that the design can bear. The design variables' manufacturing errors are depicted using the interval method, and an interval optimization model for the structure is constructed. A dimensionless design tolerance index is defined to describe the overall uncertainty of all design variables, and by combining the nominal objective function, a deterministic two-objective optimization model is built. The possibility degree of interval is used to represent the reliability of the constraints under uncertainty, through which the model is transformed to a deterministic optimization problem. Three numerical examples are investigated to verify the effectiveness of the present method.
Artificial Intelligence Methods: Challenge in Computer Based Polymer Design
NASA Astrophysics Data System (ADS)
Rusu, Teodora; Pinteala, Mariana; Cartwright, Hugh
2009-08-01
This paper deals with the use of Artificial Intelligence Methods (AI) in the design of new molecules possessing desired physical, chemical and biological properties. This is an important and difficult problem in the chemical, material and pharmaceutical industries. Traditional methods involve a laborious and expensive trial-and-error procedure, but computer-assisted approaches offer many advantages in the automation of molecular design.
An analytical method for designing low noise helicopter transmissions
NASA Technical Reports Server (NTRS)
Bossler, R. B., Jr.; Bowes, M. A.; Royal, A. C.
1978-01-01
The development and experimental validation of a method for analytically modeling the noise mechanism in the helicopter geared power transmission systems is described. This method can be used within the design process to predict interior noise levels and to investigate the noise reducing potential of alternative transmission design details. Examples are discussed.
What Can Mixed Methods Designs Offer Professional Development Program Evaluators?
ERIC Educational Resources Information Center
Giordano, Victoria; Nevin, Ann
2007-01-01
In this paper, the authors describe the benefits and pitfalls of mixed methods designs. They argue that mixed methods designs may be preferred when evaluating professional development programs for p-K-12 education given the new call for accountability in making data-driven decisions. They summarize and critique the studies in terms of limitations…
Probabilistic Methods for Uncertainty Propagation Applied to Aircraft Design
NASA Technical Reports Server (NTRS)
Green, Lawrence L.; Lin, Hong-Zong; Khalessi, Mohammad R.
2002-01-01
Three methods of probabilistic uncertainty propagation and quantification (the method of moments, Monte Carlo simulation, and a nongradient simulation search method) are applied to an aircraft analysis and conceptual design program to demonstrate design under uncertainty. The chosen example problems appear to have discontinuous design spaces and thus these examples pose difficulties for many popular methods of uncertainty propagation and quantification. However, specific implementation features of the first and third methods chosen for use in this study enable successful propagation of small uncertainties through the program. Input uncertainties in two configuration design variables are considered. Uncertainties in aircraft weight are computed. The effects of specifying required levels of constraint satisfaction with specified levels of input uncertainty are also demonstrated. The results show, as expected, that the designs under uncertainty are typically heavier and more conservative than those in which no input uncertainties exist.
Expanding color design methods for architecture and allied disciplines
NASA Astrophysics Data System (ADS)
Linton, Harold E.
2002-06-01
The color design processes of visual artists, architects, designers, and theoreticians included in this presentation reflect the practical role of color in architecture. What the color design professional brings to the architectural design team is an expertise and rich sensibility made up of a broad awareness and a finely tuned visual perception. This includes a knowledge of design and its history, expertise with industrial color materials and their methods of application, an awareness of design context and cultural identity, a background in physiology and psychology as it relates to human welfare, and an ability to problem-solve and respond creatively to design concepts with innovative ideas. The broadening of the definition of the colorists's role in architectural design provides architects, artists and designers with significant opportunities for continued professional and educational development.
Design methods for fault-tolerant finite state machines
NASA Technical Reports Server (NTRS)
Niranjan, Shailesh; Frenzel, James F.
1993-01-01
VLSI electronic circuits are increasingly being used in space-borne applications where high levels of radiation may induce faults, known as single event upsets. In this paper we review the classical methods of designing fault tolerant digital systems, with an emphasis on those methods which are particularly suitable for VLSI-implementation of finite state machines. Four methods are presented and will be compared in terms of design complexity, circuit size, and estimated circuit delay.
Aerodynamic design optimization by using a continuous adjoint method
NASA Astrophysics Data System (ADS)
Luo, JiaQi; Xiong, JunTao; Liu, Feng
2014-07-01
This paper presents the fundamentals of a continuous adjoint method and the applications of this method to the aerodynamic design optimization of both external and internal flows. General formulation of the continuous adjoint equations and the corresponding boundary conditions are derived. With the adjoint method, the complete gradient information needed in the design optimization can be obtained by solving the governing flow equations and the corresponding adjoint equations only once for each cost function, regardless of the number of design parameters. An inverse design of airfoil is firstly performed to study the accuracy of the adjoint gradient and the effectiveness of the adjoint method as an inverse design method. Then the method is used to perform a series of single and multiple point design optimization problems involving the drag reduction of airfoil, wing, and wing-body configuration, and the aerodynamic performance improvement of turbine and compressor blade rows. The results demonstrate that the continuous adjoint method can efficiently and significantly improve the aerodynamic performance of the design in a shape optimization problem.
Tabu search method with random moves for globally optimal design
NASA Astrophysics Data System (ADS)
Hu, Nanfang
1992-09-01
Optimum engineering design problems are usually formulated as non-convex optimization problems of continuous variables. Because of the absence of convexity structure, they can have multiple minima, and global optimization becomes difficult. Traditional methods of optimization, such as penalty methods, can often be trapped at a local optimum. The tabu search method with random moves to solve approximately these problems is introduced. Its reliability and efficiency are examined with the help of standard test functions. By the analysis of the implementations, it is seen that this method is easy to use, and no derivative information is necessary. It outperforms the random search method and composite genetic algorithm. In particular, it is applied to minimum weight design examples of a three-bar truss, coil springs, a Z-section and a channel section. For the channel section, the optimal design using the tabu search method with random moves saved 26.14 percent over the weight of the SUMT method.
An inverse method with regularity condition for transonic airfoil design
NASA Technical Reports Server (NTRS)
Zhu, Ziqiang; Xia, Zhixun; Wu, Liyi
1991-01-01
It is known from Lighthill's exact solution of the incompressible inverse problem that in the inverse design problem, the surface pressure distribution and the free stream speed cannot both be prescribed independently. This implies the existence of a constraint on the prescribed pressure distribution. The same constraint exists at compressible speeds. Presented here is an inverse design method for transonic airfoils. In this method, the target pressure distribution contains a free parameter that is adjusted during the computation to satisfy the regularity condition. Some design results are presented in order to demonstrate the capabilities of the method.
An artificial viscosity method for the design of supercritical airfoils
NASA Technical Reports Server (NTRS)
Mcfadden, G. B.
1979-01-01
A numerical technique is presented for the design of two-dimensional supercritical wing sections with low wave drag. The method is a design mode of the analysis code H which gives excellent agreement with experimental results and is widely used in the aircraft industry. Topics covered include the partial differential equations of transonic flow, the computational procedure and results; the design procedure; a convergence theorem; and description of the code.
Single-Case Designs and Qualitative Methods: Applying a Mixed Methods Research Perspective
ERIC Educational Resources Information Center
Hitchcock, John H.; Nastasi, Bonnie K.; Summerville, Meredith
2010-01-01
The purpose of this conceptual paper is to describe a design that mixes single-case (sometimes referred to as single-subject) and qualitative methods, hereafter referred to as a single-case mixed methods design (SCD-MM). Minimal attention has been given to the topic of applying qualitative methods to SCD work in the literature. These two…
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Investigating the Use of Design Methods by Capstone Design Students at Clemson University
ERIC Educational Resources Information Center
Miller, W. Stuart; Summers, Joshua D.
2013-01-01
The authors describe a preliminary study to understand the attitude of engineering students regarding the use of design methods in projects to identify the factors either affecting or influencing the use of these methods by novice engineers. A senior undergraduate capstone design course at Clemson University, consisting of approximately fifty…
Two-Method Planned Missing Designs for Longitudinal Research
ERIC Educational Resources Information Center
Garnier-Villarreal, Mauricio; Rhemtulla, Mijke; Little, Todd D.
2014-01-01
We examine longitudinal extensions of the two-method measurement design, which uses planned missingness to optimize cost-efficiency and validity of hard-to-measure constructs. These designs use a combination of two measures: a "gold standard" that is highly valid but expensive to administer, and an inexpensive (e.g., survey-based)…
New directions for Artificial Intelligence (AI) methods in optimum design
NASA Technical Reports Server (NTRS)
Hajela, Prabhat
1989-01-01
Developments and applications of artificial intelligence (AI) methods in the design of structural systems is reviewed. Principal shortcomings in the current approach are emphasized, and the need for some degree of formalism in the development environment for such design tools is underscored. Emphasis is placed on efforts to integrate algorithmic computations in expert systems.
Approximate method of designing a two-element airfoil
NASA Astrophysics Data System (ADS)
Abzalilov, D. F.; Mardanov, R. F.
2011-09-01
An approximate method is proposed for designing a two-element airfoil. The method is based on reducing an inverse boundary-value problem in a doubly connected domain to a problem in a singly connected domain located on a multisheet Riemann surface. The essence of the method is replacement of channels between the airfoil elements by channels of flow suction and blowing. The shape of these channels asymptotically tends to the annular shape of channels passing to infinity on the second sheet of the Riemann surface. The proposed method can be extended to designing multielement airfoils.
New knowledge network evaluation method for design rationale management
NASA Astrophysics Data System (ADS)
Jing, Shikai; Zhan, Hongfei; Liu, Jihong; Wang, Kuan; Jiang, Hao; Zhou, Jingtao
2015-01-01
Current design rationale (DR) systems have not demonstrated the value of the approach in practice since little attention is put to the evaluation method of DR knowledge. To systematize knowledge management process for future computer-aided DR applications, a prerequisite is to provide the measure for the DR knowledge. In this paper, a new knowledge network evaluation method for DR management is presented. The method characterizes the DR knowledge value from four perspectives, namely, the design rationale structure scale, association knowledge and reasoning ability, degree of design justification support and degree of knowledge representation conciseness. The DR knowledge comprehensive value is also measured by the proposed method. To validate the proposed method, different style of DR knowledge network and the performance of the proposed measure are discussed. The evaluation method has been applied in two realistic design cases and compared with the structural measures. The research proposes the DR knowledge evaluation method which can provide object metric and selection basis for the DR knowledge reuse during the product design process. In addition, the method is proved to be more effective guidance and support for the application and management of DR knowledge.
Design method for four-reflector type beam waveguide systems
NASA Technical Reports Server (NTRS)
Betsudan, S.; Katagi, T.; Urasaki, S.
1986-01-01
Discussed is a method for the design of four reflector type beam waveguide feed systems, comprised of a conical horn and 4 focused reflectors, which are used widely as the primary reflector systems for communications satellite Earth station antennas. The design parameters for these systems are clarified, the relations between each parameter are brought out based on the beam mode development, and the independent design parameters are specified. The characteristics of these systems, namely spillover loss, crosspolarization components, and frequency characteristics, and their relation to the design parameters, are also shown. It is also indicated that design parameters which decide the dimensions of the conical horn or the shape of the focused reflectors can be unerringly established once the design standard for the system has been selected as either: (1) minimizing the crosspolarization component by keeping the spillover loss to within acceptable limits, or (2) minimizing the spillover loss by maintaining the crossover components below an acceptable level and the independent design parameters, such as the respective sizes of the focused reflectors and the distances between the focussed reflectors, etc., have been established according to mechanical restrictions. A sample design is also shown. In addition to being able to clarify the effects of each of the design parameters on the system and improving insight into these systems, the efficiency of these systems will also be increased with this design method.
A multidisciplinary optimization method for designing boundary layer ingesting inlets
NASA Astrophysics Data System (ADS)
Rodriguez, David Leonard
2001-07-01
The Blended-Wing-Body is a conceptual aircraft design with rear-mounted, over-wing engines. Two types of engine installations have been considered for this aircraft. One installation is quite conventional with podded engines mounted on pylons. The other installation has partially buried engines with boundary layer ingesting inlets. Although ingesting the low-momentum flow in a boundary layer can improve propulsive efficiency, poor inlet performance can offset and even overwhelm this potential advantage. For both designs, the tight coupling between the aircraft aerodynamics and the propulsion system poses a difficult design integration problem. This dissertation presents a design method that solves the problem using multidisciplinary optimization. A Navier-Stokes flow solver, an engine analysis method, and a nonlinear optimizer are combined into a design tool that correctly addresses the tight coupling of the problem. The method is first applied to a model 2D problem to expedite development and thoroughly test the scheme. The low computational cost of the 2D method allows for several inlet installations to be optimized and analyzed. The method is then upgraded by using a validated 3D Navier-Stokes solver. The two candidate engine installations are analyzed and optimized using this inlet design method. The method is shown to be quite effective at integrating the propulsion and aerodynamic systems of the Blend-Wing-Body for both engine installations by improving overall performance and satisfying any specified design constraints. By comparing the two optimized designs, the potential advantages of ingesting boundary layer flow for this aircraft are demonstrated.
Epidemiological designs for vaccine safety assessment: methods and pitfalls.
Andrews, Nick
2012-09-01
Three commonly used designs for vaccine safety assessment post licensure are cohort, case-control and self-controlled case series. These methods are often used with routine health databases and immunisation registries. This paper considers the issues that may arise when designing an epidemiological study, such as understanding the vaccine safety question, case definition and finding, limitations of data sources, uncontrolled confounding, and pitfalls that apply to the individual designs. The example of MMR and autism, where all three designs have been used, is presented to help consider these issues. PMID:21985898
Design of diffractive optical surfaces within the nonimaging SMS design method
NASA Astrophysics Data System (ADS)
Mendes-Lopes, João.; Benítez, Pablo; Miñano, Juan C.
2015-09-01
The Simultaneous Multiple Surface (SMS) method was initially developed as a design method in Nonimaging Optics and later, the method was extended for designing Imaging Optics. We show an extension of the SMS method to diffractive surfaces. Using this method, diffractive kinoform surfaces are calculated simultaneously and through a direct method, i. e. it is not based in multi-parametric optimization techniques. Using the phase-shift properties of diffractive surfaces as an extra degree of freedom, only N/2 surfaces are needed to perfectly couple N one parameter wavefronts. Wavefronts of different wavelengths can also be coupled, hence chromatic aberration can be corrected in SMS-based systems. This method can be used by combining and calculating simultaneously both reflective, refractive and diffractive surfaces, through direct calculation of phase and refractive/reflective profiles. Representative diffractive systems designed by the SMS method are presented.
A Bright Future for Evolutionary Methods in Drug Design.
Le, Tu C; Winkler, David A
2015-08-01
Most medicinal chemists understand that chemical space is extremely large, essentially infinite. Although high-throughput experimental methods allow exploration of drug-like space more rapidly, they are still insufficient to fully exploit the opportunities that such large chemical space offers. Evolutionary methods can synergistically blend automated synthesis and characterization methods with computational design to identify promising regions of chemical space more efficiently. We describe how evolutionary methods are implemented, and provide examples of published drug development research in which these methods have generated molecules with increased efficacy. We anticipate that evolutionary methods will play an important role in future drug discovery. PMID:26059362
A comparison of methods for DPLL loop filter design
NASA Technical Reports Server (NTRS)
Aguirre, S.; Hurd, W. J.; Kumar, R.; Statman, J.
1986-01-01
Four design methodologies for loop filters for a class of digital phase-locked loops (DPLLs) are presented. The first design maps an optimum analog filter into the digital domain; the second approach designs a filter that minimizes in discrete time weighted combination of the variance of the phase error due to noise and the sum square of the deterministic phase error component; the third method uses Kalman filter estimation theory to design a filter composed of a least squares fading memory estimator and a predictor. The last design relies on classical theory, including rules for the design of compensators. Linear analysis is used throughout the article to compare different designs, and includes stability, steady state performance and transient behavior of the loops. Design methodology is not critical when the loop update rate can be made high relative to loop bandwidth, as the performance approaches that of continuous time. For low update rates, however, the miminization method is significantly superior to the other methods.
XML-based product information processing method for product design
NASA Astrophysics Data System (ADS)
Zhang, Zhen Yu
2012-01-01
Design knowledge of modern mechatronics product is based on information processing as the center of the knowledge-intensive engineering, thus product design innovation is essentially the knowledge and information processing innovation. Analysis of the role of mechatronics product design knowledge and information management features, a unified model of XML-based product information processing method is proposed. Information processing model of product design includes functional knowledge, structural knowledge and their relationships. For the expression of product function element, product structure element, product mapping relationship between function and structure based on the XML model are proposed. The information processing of a parallel friction roller is given as an example, which demonstrates that this method is obviously helpful for knowledge-based design system and product innovation.
XML-based product information processing method for product design
NASA Astrophysics Data System (ADS)
Zhang, Zhen Yu
2011-12-01
Design knowledge of modern mechatronics product is based on information processing as the center of the knowledge-intensive engineering, thus product design innovation is essentially the knowledge and information processing innovation. Analysis of the role of mechatronics product design knowledge and information management features, a unified model of XML-based product information processing method is proposed. Information processing model of product design includes functional knowledge, structural knowledge and their relationships. For the expression of product function element, product structure element, product mapping relationship between function and structure based on the XML model are proposed. The information processing of a parallel friction roller is given as an example, which demonstrates that this method is obviously helpful for knowledge-based design system and product innovation.
Novel parameter-based flexure bearing design method
NASA Astrophysics Data System (ADS)
Amoedo, Simon; Thebaud, Edouard; Gschwendtner, Michael; White, David
2016-06-01
A parameter study was carried out on the design variables of a flexure bearing to be used in a Stirling engine with a fixed axial displacement and a fixed outer diameter. A design method was developed in order to assist identification of the optimum bearing configuration. This was achieved through a parameter study of the bearing carried out with ANSYS®. The parameters varied were the number and the width of the arms, the thickness of the bearing, the eccentricity, the size of the starting and ending holes, and the turn angle of the spiral. Comparison was made between the different designs in terms of axial and radial stiffness, the natural frequency, and the maximum induced stresses. Moreover, the Finite Element Analysis (FEA) was compared to theoretical results for a given design. The results led to a graphical design method which assists the selection of flexure bearing geometrical parameters based on pre-determined geometric and material constraints.
A computational design method for transonic turbomachinery cascades
NASA Technical Reports Server (NTRS)
Sobieczky, H.; Dulikravich, D. S.
1982-01-01
This paper describes a systematical computational procedure to find configuration changes necessary to modify the resulting flow past turbomachinery cascades, channels and nozzles, to be shock-free at prescribed transonic operating conditions. The method is based on a finite area transonic analysis technique and the fictitious gas approach. This design scheme has two major areas of application. First, it can be used for design of supercritical cascades, with applications mainly in compressor blade design. Second, it provides subsonic inlet shapes including sonic surfaces with suitable initial data for the design of supersonic (accelerated) exits, like nozzles and turbine cascade shapes. This fast, accurate and economical method with a proven potential for applications to three-dimensional flows is illustrated by some design examples.
Risk-based methods applicable to ranking conceptual designs
Breeding, R.J.; Ortiz, K.; Ringland, J.T.; Lim, J.J.
1993-11-01
In Ginichi Taguchi`s latest book on quality engineering, an emphasis is placed on robust design processes in which quality engineering techniques are brought ``upstream,`` that is, they are utilized as early as possible, preferably in the conceptual design stage. This approach was used in a study of possible future safety system designs for weapons. As an experiment, a method was developed for using probabilistic risk analysis (PRA) techniques to rank conceptual designs for performance against a safety metric for ultimate incorporation into a Pugh matrix evaluation. This represents a high-level UW application of PRA methods to weapons. As with most conceptual designs, details of the implementation were not yet developed; many of the components had never been built, let alone tested. Therefore, our application of risk assessment methods was forced to be at such a high level that the entire evaluation could be performed on a spreadsheet. Nonetheless, the method produced numerical estimates of safety in a manner that was consistent, reproducible, and scrutable. The results enabled us to rank designs to identify areas where returns on research efforts would be the greatest. The numerical estimates were calibrated against what is achievable by current weapon safety systems. The use of expert judgement is inescapable, but these judgements are explicit and the method is easily implemented on an spreadsheet computer program.
Designing, Teaching, and Evaluating Two Complementary Mixed Methods Research Courses
ERIC Educational Resources Information Center
Christ, Thomas W.
2009-01-01
Teaching mixed methods research is difficult. This longitudinal explanatory study examined how two classes were designed, taught, and evaluated. Curriculum, Research, and Teaching (EDCS-606) and Mixed Methods Research (EDCS-780) used a research proposal generation process to highlight the importance of the purpose, research question and…
INNOVATIVE METHODS FOR THE OPTIMIZATION OF GRAVITY STORM SEWER DESIGN
The purpose of this paper is to describe a new method for optimizing the design of urban storm sewer systems. Previous efforts to optimize gravity sewers have met with limited success because classical optimization methods require that the problem be well behaved, e.g. describ...
NASA Technical Reports Server (NTRS)
Dezfuli, Homayoon
2010-01-01
This slide presentation reviews the evolution of risk management (RM) at NASA. The aim of the RM approach at NASA is to promote an approach that is heuristic, proactive, and coherent across all of NASA. Risk Informed Decision Making (RIDM) is a decision making process that uses a diverse set of performance measures along with other considerations within a deliberative process to inform decision making. RIDM is invoked for key decisions such as architecture and design decisions, make-buy decisions, and budget reallocation. The RIDM process and how it relates to the continuous Risk Management (CRM) process is reviewed.
FRP bolted flanged connections -- Modern design and fabrication methods
Blach, A.E.; Sun, L.
1995-11-01
Bolted flanged connections for fiber reinforced plastic (FRP) pipes and pressure vessels are of great importance for any user of FRP material in fluid containment applications. At present, no dimensional standards or design rules exist for FRP flanges. Most often, flanges are fabricated to dimensional standards for metallic flanges without questioning their applicability to FRP materials. This paper discusses simplified and exact design methods for composite flanges, based on isotropic material design and on laminate theory design. Both, exact and simplified methods are included. Results of various design methods are then compared with experimental results from strain gage measurements on test pressure vessels. Methods of flange fabrication such as hand lay-up, injection molding, filament winding, and others, are discussed for their relative merits in pressure vessel and piping applications. Both, integral and bonded flanges are covered as applicable to the various methods of fabrication, also the economic implications of these methods. Also treated are the problems of gasket selection, bolting and overbolting, gasket stresses, and leakage of flanged connections.
Optimal Input Signal Design for Data-Centric Estimation Methods.
Deshpande, Sunil; Rivera, Daniel E
2013-01-01
Data-centric estimation methods such as Model-on-Demand and Direct Weight Optimization form attractive techniques for estimating unknown functions from noisy data. These methods rely on generating a local function approximation from a database of regressors at the current operating point with the process repeated at each new operating point. This paper examines the design of optimal input signals formulated to produce informative data to be used by local modeling procedures. The proposed method specifically addresses the distribution of the regressor vectors. The design is examined for a linear time-invariant system under amplitude constraints on the input. The resulting optimization problem is solved using semidefinite relaxation methods. Numerical examples show the benefits in comparison to a classical PRBS input design. PMID:24317042
Test methods and design allowables for fibrous composites. Volume 2
NASA Technical Reports Server (NTRS)
Chamis, Christos C. (Editor)
1989-01-01
Topics discussed include extreme/hostile environment testing, establishing design allowables, and property/behavior specific testing. Papers are presented on environmental effects on the high strain rate properties of graphite/epoxy composite, the low-temperature performance of short-fiber reinforced thermoplastics, the abrasive wear behavior of unidirectional and woven graphite fiber/PEEK, test methods for determining design allowables for fiber reinforced composites, and statistical methods for calculating material allowables for MIL-HDBK-17. Attention is also given to a test method to measure the response of composite materials under reversed cyclic loads, a through-the-thickness strength specimen for composites, the use of torsion tubes to measure in-plane shear properties of filament-wound composites, the influlence of test fixture design on the Iosipescu shear test for fiber composite materials, and a method for monitoring in-plane shear modulus in fatigue testing of composites.
Optimal Input Signal Design for Data-Centric Estimation Methods
Deshpande, Sunil; Rivera, Daniel E.
2013-01-01
Data-centric estimation methods such as Model-on-Demand and Direct Weight Optimization form attractive techniques for estimating unknown functions from noisy data. These methods rely on generating a local function approximation from a database of regressors at the current operating point with the process repeated at each new operating point. This paper examines the design of optimal input signals formulated to produce informative data to be used by local modeling procedures. The proposed method specifically addresses the distribution of the regressor vectors. The design is examined for a linear time-invariant system under amplitude constraints on the input. The resulting optimization problem is solved using semidefinite relaxation methods. Numerical examples show the benefits in comparison to a classical PRBS input design. PMID:24317042
Tradeoff methods in multiobjective insensitive design of airplane control systems
NASA Technical Reports Server (NTRS)
Schy, A. A.; Giesy, D. P.
1984-01-01
The latest results of an ongoing study of computer-aided design of airplane control systems are given. Constrained minimization algorithms are used, with the design objectives in the constraint vector. The concept of Pareto optimiality is briefly reviewed. It is shown how an experienced designer can use it to find designs which are well-balanced in all objectives. Then the problem of finding designs which are insensitive to uncertainty in system parameters are discussed, introducing a probabilistic vector definition of sensitivity which is consistent with the deterministic Pareto optimal problem. Insensitivity is important in any practical design, but it is particularly important in the design of feedback control systems, since it is considered to be the most important distinctive property of feedback control. Methods of tradeoff between deterministic and stochastic-insensitive (SI) design are described, and tradeoff design results are presented for the example of the a Shuttle lateral stability augmentation system. This example is used because careful studies have been made of the uncertainty in Shuttle aerodynamics. Finally, since accurate statistics of uncertain parameters are usually not available, the effects of crude statistical models on SI designs are examined.
A new method of VLSI conform design for MOS cells
NASA Astrophysics Data System (ADS)
Schmidt, K. H.; Wach, W.; Mueller-Glaser, K. D.
An automated method for the design of specialized SSI/LSI-level MOS cells suitable for incorporation in VLSI chips is described. The method uses the symbolic-layout features of the CABBAGE computer program (Hsueh, 1979; De Man et al., 1982), but restricted by a fixed grid system to facilitate compaction procedures. The techniques used are shown to significantly speed the processes of electrical design, layout, design verification, and description for subsequent CAD/CAM application. In the example presented, a 211-transistor, parallel-load, synchronous 4-bit up/down binary counter cell was designed in 9 days, as compared to 30 days for a manually-optimized-layout version and 3 days for a larger, less efficient cell designed by a programmable logic array; the cell areas were 0.36, 0.21, and 0.79 sq mm, respectively. The primary advantage of the method is seen in the extreme ease with which the cell design can be adapted to new parameters or design rules imposed by improvements in technology.
Computer method for design of acoustic liners for turbofan engines
NASA Technical Reports Server (NTRS)
Minner, G. L.; Rice, E. J.
1976-01-01
A design package is presented for the specification of acoustic liners for turbofans. An estimate of the noise generation was made based on modifications of existing noise correlations, for which the inputs are basic fan aerodynamic design variables. The method does not predict multiple pure tones. A target attenuation spectrum was calculated which was the difference between the estimated generation spectrum and a flat annoyance-weighted goal attenuated spectrum. The target spectrum was combined with a knowledge of acoustic liner performance as a function of the liner design variables to specify the acoustic design. The liner design method at present is limited to annular duct configurations. The detailed structure of the liner was specified by combining the required impedance (which is a result of the previous step) with a mathematical model relating impedance to the detailed structure. The design procedure was developed for a liner constructed of perforated sheet placed over honeycomb backing cavities. A sample calculation was carried through in order to demonstrate the design procedure, and experimental results presented show good agreement with the calculated results of the method.
Method for Enzyme Design with Genetically Encoded Unnatural Amino Acids.
Hu, C; Wang, J
2016-01-01
We describe the methodologies for the design of artificial enzymes with genetically encoded unnatural amino acids. Genetically encoded unnatural amino acids offer great promise for constructing artificial enzymes with novel activities. In our studies, the designs of artificial enzyme were divided into two steps. First, we considered the unnatural amino acids and the protein scaffold separately. The scaffold is designed by traditional protein design methods. The unnatural amino acids are inspired by natural structure and organic chemistry methods, and synthesized by either organic chemistry methods or enzymatic conversion. With the increasing number of published unnatural amino acids with various functions, we described an unnatural amino acids toolkit containing metal chelators, redox mediators, and click chemistry reagents. These efforts enable a researcher to search the toolkit for appropriate unnatural amino acids for the study, rather than design and synthesize the unnatural amino acids from the beginning. After the first step, the model enzyme was optimized by computational methods and directed evolution. Lastly, we describe a general method for evolving aminoacyl-tRNA synthetase and expressing unnatural amino acids incorporated into a protein. PMID:27586330
The Air Risk Information Support Center (Air RISC) has been organized by U.S. EPA's offices of Air Quality Planning and Standards and Health and Environmental Assessment. The center has been developed in cooperation with the State and Territorial air Pollution Control Program Adm...
Developing Conceptual Hypersonic Airbreathing Engines Using Design of Experiments Methods
NASA Technical Reports Server (NTRS)
Ferlemann, Shelly M.; Robinson, Jeffrey S.; Martin, John G.; Leonard, Charles P.; Taylor, Lawrence W.; Kamhawi, Hilmi
2000-01-01
Designing a hypersonic vehicle is a complicated process due to the multi-disciplinary synergy that is required. The greatest challenge involves propulsion-airframe integration. In the past, a two-dimensional flowpath was generated based on the engine performance required for a proposed mission. A three-dimensional CAD geometry was produced from the two-dimensional flowpath for aerodynamic analysis, structural design, and packaging. The aerodynamics, engine performance, and mass properties arc inputs to the vehicle performance tool to determine if the mission goals were met. If the mission goals were not met, then a flowpath and vehicle redesign would begin. This design process might have to be performed several times to produce a "closed" vehicle. This paper will describe an attempt to design a hypersonic cruise vehicle propulsion flowpath using a Design of' Experiments method to reduce the resources necessary to produce a conceptual design with fewer iterations of the design cycle. These methods also allow for more flexible mission analysis and incorporation of additional design constraints at any point. A design system was developed using an object-based software package that would quickly generate each flowpath in the study given the values of the geometric independent variables. These flowpath geometries were put into a hypersonic propulsion code and the engine performance was generated. The propulsion results were loaded into statistical software to produce regression equations that were combined with an aerodynamic database to optimize the flowpath at the vehicle performance level. For this example, the design process was executed twice. The first pass was a cursory look at the independent variables selected to determine which variables are the most important and to test all of the inputs to the optimization process. The second cycle is a more in-depth study with more cases and higher order equations representing the design space.
Federal Register 2010, 2011, 2012, 2013, 2014
2010-12-10
... AGENCY Integrated Risk Information System (IRIS); Announcement of Availability of Literature Searches for... literature searches for IRIS assessments; request for information. SUMMARY: The U.S. Environmental Protection Agency (EPA) is announcing the availability of literature searches for four IRIS...
A Tutorial on Probablilistic Risk Assessement and its Role in Risk-Informed Decision Making
NASA Technical Reports Server (NTRS)
Dezfuli, Homayoon
2010-01-01
This slide presentation reviews risk assessment and its role in risk-informed decision making. It includes information on probabilistic risk assessment, typical risk management process, origins of risk matrix, performance measures, performance objectives and Bayes theorem.
A decentralized linear quadratic control design method for flexible structures
NASA Technical Reports Server (NTRS)
Su, Tzu-Jeng; Craig, Roy R., Jr.
1990-01-01
A decentralized suboptimal linear quadratic control design procedure which combines substructural synthesis, model reduction, decentralized control design, subcontroller synthesis, and controller reduction is proposed for the design of reduced-order controllers for flexible structures. The procedure starts with a definition of the continuum structure to be controlled. An evaluation model of finite dimension is obtained by the finite element method. Then, the finite element model is decomposed into several substructures by using a natural decomposition called substructuring decomposition. Each substructure, at this point, still has too large a dimension and must be reduced to a size that is Riccati-solvable. Model reduction of each substructure can be performed by using any existing model reduction method, e.g., modal truncation, balanced reduction, Krylov model reduction, or mixed-mode method. Then, based on the reduced substructure model, a subcontroller is designed by an LQ optimal control method for each substructure independently. After all subcontrollers are designed, a controller synthesis method called substructural controller synthesis is employed to synthesize all subcontrollers into a global controller. The assembling scheme used is the same as that employed for the structure matrices. Finally, a controller reduction scheme, called the equivalent impulse response energy controller (EIREC) reduction algorithm, is used to reduce the global controller to a reasonable size for implementation. The EIREC reduced controller preserves the impulse response energy of the full-order controller and has the property of matching low-frequency moments and low-frequency power moments. An advantage of the substructural controller synthesis method is that it relieves the computational burden associated with dimensionality. Besides that, the SCS design scheme is also a highly adaptable controller synthesis method for structures with varying configuration, or varying mass
Study on Communication System of Social Risk Information on Nuclear Energy
Hidekazu Yoshikawa; Toshio Sugiman; Yasunaga Wakabayashi; Hiroshi Shimoda; Mika Terado; Mariko Akimoto; Yoshihiko Nagasato
2004-07-01
As a new risk communication method for the construction of effective knowledge bases about 'safety and non-anxiety for nuclear energy', a study on new communication method of social risk information by means of electronic communication has been started, by noticing rapid expansion of internet usage in the society. The purpose of this research is to enhance the public acceptance to nuclear power in Japan by the following two aspects. The first is to develop the mutual communication system among the working persons involved in both the operation and maintenance activities for nuclear power plant, by which they will exchange their daily experiences to improve the safety conscious activities to foster 'safety culture' attitude. The other is the development of an effective risk communication system between nuclear society and the general publics about the hot issues of 'what are the concerned involved in the final disposal of high-level radioactive waste?' and 'what should we do to have social consensus to deal with this issue in future'. The authors' research plan for the above purpose is summarized as shown in Table 1. As the first step of the authors' three year research project which started from August 2003, social investigation by questionnaires by internet and postal mail, have been just recently conducted on their risk perception for the nuclear power for the people engaged in nuclear business and women in the metropolitan area, respectively, in order to obtain the relevant information on how and what should be considered for constructing effective risk communication methods of social risk information between the people within nuclear industries and the general public in society. Although there need to be discussed, the contrasting risk images as shown in Fig.1, can be depicted between the nuclear people and general public these days in Japan, from the results of the social investigation. As the conclusion of the authors' study thus far conducted, the
Climate Risk Informed Decision Analysis: A Hypothetical Application to the Waas Region
NASA Astrophysics Data System (ADS)
Gilroy, Kristin; Mens, Marjolein; Haasnoot, Marjolijn; Jeuken, Ad
2016-04-01
More frequent and intense hydrologic events under climate change are expected to enhance water security and flood risk management challenges worldwide. Traditional planning approaches must be adapted to address climate change and develop solutions with an appropriate level of robustness and flexibility. The Climate Risk Informed Decision Analysis (CRIDA) method is a novel planning approach embodying a suite of complementary methods, including decision scaling and adaptation pathways. Decision scaling offers a bottom-up approach to assess risk and tailors the complexity of the analysis to the problem at hand and the available capacity. Through adaptation pathway,s an array of future strategies towards climate robustness are developed, ranging in flexibility and immediacy of investments. Flexible pathways include transfer points to other strategies to ensure that the system can be adapted if future conditions vary from those expected. CRIDA combines these two approaches in a stakeholder driven process which guides decision makers through the planning and decision process, taking into account how the confidence in the available science, the consequences in the system, and the capacity of institutions should influence strategy selection. In this presentation, we will explain the CRIDA method and compare it to existing planning processes, such as the US Army Corps of Engineers Principles and Guidelines as well as Integrated Water Resources Management Planning. Then, we will apply the approach to a hypothetical case study for the Waas Region, a large downstream river basin facing rapid development threatened by increased flood risks. Through the case study, we will demonstrate how a stakeholder driven process can be used to evaluate system robustness to climate change; develop adaptation pathways for multiple objectives and criteria; and illustrate how varying levels of confidence, consequences, and capacity would play a role in the decision making process, specifically
The conditional risk probability-based seawall height design method
NASA Astrophysics Data System (ADS)
Yang, Xing; Hu, Xiaodong; Li, Zhiqing
2015-11-01
The determination of the required seawall height is usually based on the combination of wind speed (or wave height) and still water level according to a specified return period, e.g., 50-year return period wind speed and 50-year return period still water level. In reality, the two variables are be partially correlated. This may be lead to over-design (costs) of seawall structures. The above-mentioned return period for the design of a seawall depends on economy, society and natural environment in the region. This means a specified risk level of overtopping or damage of a seawall structure is usually allowed. The aim of this paper is to present a conditional risk probability-based seawall height design method which incorporates the correlation of the two variables. For purposes of demonstration, the wind speeds and water levels collected from Jiangsu of China are analyzed. The results show this method can improve seawall height design accuracy.
Mixed methods research design for pragmatic psychoanalytic studies.
Tillman, Jane G; Clemence, A Jill; Stevens, Jennifer L
2011-10-01
Calls for more rigorous psychoanalytic studies have increased over the past decade. The field has been divided by those who assert that psychoanalysis is properly a hermeneutic endeavor and those who see it as a science. A comparable debate is found in research methodology, where qualitative and quantitative methods have often been seen as occupying orthogonal positions. Recently, Mixed Methods Research (MMR) has emerged as a viable "third community" of research, pursuing a pragmatic approach to research endeavors through integrating qualitative and quantitative procedures in a single study design. Mixed Methods Research designs and the terminology associated with this emerging approach are explained, after which the methodology is explored as a potential integrative approach to a psychoanalytic human science. Both qualitative and quantitative research methods are reviewed, as well as how they may be used in Mixed Methods Research to study complex human phenomena. PMID:21880844
Rotordynamics and Design Methods of an Oil-Free Turbocharger
NASA Technical Reports Server (NTRS)
Howard, Samuel A.
1999-01-01
The feasibility of supporting a turbocharger rotor on air foil bearings is investigated based upon predicted rotordynamic stability, load accommodations, and stress considerations. It is demonstrated that foil bearings offer a plausible replacement for oil-lubricated bearings in diesel truck turbochargers. Also, two different rotor configurations are analyzed and the design is chosen which best optimizes the desired performance characteristics. The method of designing machinery for foil bearing use and the assumptions made are discussed.
Design of large Francis turbine using optimal methods
NASA Astrophysics Data System (ADS)
Flores, E.; Bornard, L.; Tomas, L.; Liu, J.; Couston, M.
2012-11-01
Among a high number of Francis turbine references all over the world, covering the whole market range of heads, Alstom has especially been involved in the development and equipment of the largest power plants in the world : Three Gorges (China -32×767 MW - 61 to 113 m), Itaipu (Brazil- 20x750 MW - 98.7m to 127m) and Xiangjiaba (China - 8x812 MW - 82.5m to 113.6m - in erection). Many new projects are under study to equip new power plants with Francis turbines in order to answer an increasing demand of renewable energy. In this context, Alstom Hydro is carrying out many developments to answer those needs, especially for jumbo units such the planned 1GW type units in China. The turbine design for such units requires specific care by using the state of the art in computation methods and the latest technologies in model testing as well as the maximum feedback from operation of Jumbo plants already in operation. We present in this paper how a large Francis turbine can be designed using specific design methods, including the global and local optimization methods. The design of the spiral case, the tandem cascade profiles, the runner and the draft tube are designed with optimization loops involving a blade design tool, an automatic meshing software and a Navier-Stokes solver, piloted by a genetic algorithm. These automated optimization methods, presented in different papers over the last decade, are nowadays widely used, thanks to the growing computation capacity of the HPC clusters: the intensive use of such optimization methods at the turbine design stage allows to reach very high level of performances, while the hydraulic flow characteristics are carefully studied over the whole water passage to avoid any unexpected hydraulic phenomena.
Gray, Stacy W.; O’Grady, Cristin; Karp, Lauren; Smith, Daniel; Schwartz, J. Sanford; Hornik, Robert C.; Armstrong, Katrina
2009-01-01
Background Direct to consumer (DTC) BRCA testing may expand access to genetic testing and enhance cancer prevention efforts. However, it is not know if current DTC websites provide adequate risk information for informed medical decision-making. Methods 284 women with a personal or family history of breast/ovarian cancer were randomly assigned to view a “mock” DTC commercial website (control condition: CC, n=93) or the same “mock” website that included information on the potential risks of obtaining genetic testing online. Risk information was framed two ways: risk information attributed to expert sources (ES, n=98) and unattributed risk information (URI, n=93). Participants completed an online survey. Endpoints were intentions to get BRCA testing, testing site preference and beliefs about DTC BRCA testing. Results Sample characteristics: mean age 39 (range 18–70), 82% white, mean education 3 yrs. college. Women exposed to risk information had lower intentions to get BRCA testing than women in the CC (adjusted odds ratio (OR) 0.48; 95% confidence interval (CI) 0.26–0.87, p=0.016), less positive beliefs about online BRCA testing (adjusted OR 0.48; 95% 0.27–0.86, p=0.014). Women in the ES condition were more likely to prefer clinic based testing than women in the CC (adjusted OR 2.05; 95% CI 1.07–3.90, p=0.030). Conclusion Exposing women to information on the potential risks of online BRCA testing altered their intentions, beliefs and preferences for BRCA testing. Policy makers may want to consider content and framing of risk information on DTC websites as they formulate regulation for this rapidly growing industry. PMID:19318436
A finite-difference method for transonic airfoil design.
NASA Technical Reports Server (NTRS)
Steger, J. L.; Klineberg, J. M.
1972-01-01
This paper describes an inverse method for designing transonic airfoil sections or for modifying existing profiles. Mixed finite-difference procedures are applied to the equations of transonic small disturbance theory to determine the airfoil shape corresponding to a given surface pressure distribution. The equations are solved for the velocity components in the physical domain and flows with embedded shock waves can be calculated. To facilitate airfoil design, the method allows alternating between inverse and direct calculations to obtain a profile shape that satisfies given geometric constraints. Examples are shown of the application of the technique to improve the performance of several lifting airfoil sections. The extension of the method to three dimensions for designing supercritical wings is also indicated.
Improved method for transonic airfoil design-by-optimization
NASA Technical Reports Server (NTRS)
Kennelly, R. A., Jr.
1983-01-01
An improved method for use of optimization techniques in transonic airfoil design is demonstrated. FLO6QNM incorporates a modified quasi-Newton optimization package, and is shown to be more reliable and efficient than the method developed previously at NASA-Ames, which used the COPES/CONMIN optimization problem. The design codes are compared on a series of test cases with known solutions, and the effects of problem scaling, proximity of initial point to solution, and objective function precision are studied. In contrast to the older method, well-converged solutions are shown to be attainable in the context of engineering design using computational fluid dynamics tools, a new result. The improvements are due to better performance by the optimization routine and to the use of problem-adaptive finite difference step sizes for gradient evaluation.
Improved method for transonic airfoil design-by-optimization
NASA Technical Reports Server (NTRS)
Kennelly, R. A., Jr.
1983-01-01
An improved method for use of optimization techniques in transonic airfoil design is demonstrated. FLO6QNM incorporates a modified quasi-Newton optimization package, and is shown to be more reliable and efficient than the method developed previously at NASA-Ames, which used the COPES/CONMIN optimization program. The design codes are compared on a series of test cases with known solutions, and the effects of problem scaling, proximity of initial point to solution, and objective function precision are studied. In contrast to the older method, well-converged solutions are shown to be attainable in the context of engineering design using computational fluid dynamics tools, a new result. The improvements are due to better performance by the optimization routine and to the use of problem-adaptive finite difference step sizes for gradient evaluation.
Computational methods of robust controller design for aerodynamic flutter suppression
NASA Technical Reports Server (NTRS)
Anderson, L. R.
1981-01-01
The development of Riccati iteration, a tool for the design and analysis of linear control systems is examined. First, Riccati iteration is applied to the problem of pole placement and order reduction in two-time scale control systems. Order reduction, yielding a good approximation to the original system, is demonstrated using a 16th order linear model of a turbofan engine. Next, a numerical method for solving the Riccati equation is presented and demonstrated for a set of eighth order random examples. A literature review of robust controller design methods follows which includes a number of methods for reducing the trajectory and performance index sensitivity in linear regulators. Lastly, robust controller design for large parameter variations is discussed.
A method for the probabilistic design assessment of composite structures
NASA Technical Reports Server (NTRS)
Shiao, Michael C.; Singhal, Surendra N.; Chamis, Christos C.
1994-01-01
A formal procedure for the probabilistic design assessment of a composite structure is described. The uncertainties in all aspects of a composite structure (constituent material properties, fabrication variables, structural geometry, service environments, etc.), which result in the uncertain behavior in the composite structural responses, are included in the assessment. The probabilistic assessment consists of design criteria, modeling of composite structures and uncertainties, simulation methods, and the decision making process. A sample case is presented to illustrate the formal procedure and to demonstrate that composite structural designs can be probabilistically assessed with accuracy and efficiency.
Cohen, A A; Shatzmiller, S E
1993-09-01
This study presents an algorithm that implements artificial-intelligence techniques for automated, and site-directed drug design. The aim of the method is to link two or more predetermined functional groups into a sensible molecular structure. The proposed designing process mimics the classical manual design method, in which the drug designer sits in front of the computer screen and with the aid of computer graphics attempts to design the new drug. Therefore, the key principle of the algorithm is the parameterization of some criteria that affect the decision-making process carried out by the drug designer. This parameterization is based on the generation of weighting factors that reflect the knowledge and knowledge-based intuition of the drug designer, and thus add further rationalization to the drug design process. The proposed algorithm has been shown to yield a large variety of different structures, of which the drug designer may choose the most sensible. Performance tests indicate that with the proper set of parameters, the method generates a new structure within a short time. PMID:8110662
Inverse design of airfoils using a flexible membrane method
NASA Astrophysics Data System (ADS)
Thinsurat, Kamon
The Modified Garabedian Mc-Fadden (MGM) method is used to inversely design airfoils. The Finite Difference Method (FDM) for Non-Uniform Grids was developed to discretize the MGM equation for numerical solving. The Finite Difference Method (FDM) for Non-Uniform Grids has the advantage of being used flexibly with an unstructured grids airfoil. The commercial software FLUENT is being used as the flow solver. Several conditions are set in FLUENT such as subsonic inviscid flow, subsonic viscous flow, transonic inviscid flow, and transonic viscous flow to test the inverse design code for each condition. A moving grid program is used to create a mesh for new airfoils prior to importing meshes into FLUENT for the analysis of flows. For validation, an iterative process is used so the Cp distribution of the initial airfoil, the NACA0011, achieves the Cp distribution of the target airfoil, the NACA2315, for the subsonic inviscid case at M=0.2. Three other cases were carried out to validate the code. After the code validations, the inverse design method was used to design a shock free airfoil in the transonic condition and to design a separation free airfoil at a high angle of attack in the subsonic condition.
Federal Register 2010, 2011, 2012, 2013, 2014
2012-05-17
... COMMISSION An Approach for Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes... Assessment in Risk- Informed Decisions on Plant-Specific Changes to the Licensing Basis,'' (proposed Revision... Assessment Results for Risk-Informed Activities'' and the references were updated. It is the intent of...
Evaluation of Methods for Multidisciplinary Design Optimization (MDO). Phase 1
NASA Technical Reports Server (NTRS)
Kodiyalam, Srinivas
1998-01-01
The NASA Langley Multidisciplinary Design Optimization (MDO) method evaluation study seeks to arrive at a set of guidelines for using promising MDO methods by accumulating and analyzing computational data for such methods. The data are collected by conducting a series of reproducible experiments. This report documents all computational experiments conducted in Phase I of the study. This report is a companion to the paper titled Initial Results of an MDO Method Evaluation Study by N. M. Alexandrov and S. Kodiyalam (AIAA-98-4884).
Exploration of Advanced Probabilistic and Stochastic Design Methods
NASA Technical Reports Server (NTRS)
Mavris, Dimitri N.
2003-01-01
The primary objective of the three year research effort was to explore advanced, non-deterministic aerospace system design methods that may have relevance to designers and analysts. The research pursued emerging areas in design methodology and leverage current fundamental research in the area of design decision-making, probabilistic modeling, and optimization. The specific focus of the three year investigation was oriented toward methods to identify and analyze emerging aircraft technologies in a consistent and complete manner, and to explore means to make optimal decisions based on this knowledge in a probabilistic environment. The research efforts were classified into two main areas. First, Task A of the grant has had the objective of conducting research into the relative merits of possible approaches that account for both multiple criteria and uncertainty in design decision-making. In particular, in the final year of research, the focus was on the comparison and contrasting between three methods researched. Specifically, these three are the Joint Probabilistic Decision-Making (JPDM) technique, Physical Programming, and Dempster-Shafer (D-S) theory. The next element of the research, as contained in Task B, was focused upon exploration of the Technology Identification, Evaluation, and Selection (TIES) methodology developed at ASDL, especially with regards to identification of research needs in the baseline method through implementation exercises. The end result of Task B was the documentation of the evolution of the method with time and a technology transfer to the sponsor regarding the method, such that an initial capability for execution could be obtained by the sponsor. Specifically, the results of year 3 efforts were the creation of a detailed tutorial for implementing the TIES method. Within the tutorial package, templates and detailed examples were created for learning and understanding the details of each step. For both research tasks, sample files and
A PDE Sensitivity Equation Method for Optimal Aerodynamic Design
NASA Technical Reports Server (NTRS)
Borggaard, Jeff; Burns, John
1996-01-01
The use of gradient based optimization algorithms in inverse design is well established as a practical approach to aerodynamic design. A typical procedure uses a simulation scheme to evaluate the objective function (from the approximate states) and its gradient, then passes this information to an optimization algorithm. Once the simulation scheme (CFD flow solver) has been selected and used to provide approximate function evaluations, there are several possible approaches to the problem of computing gradients. One popular method is to differentiate the simulation scheme and compute design sensitivities that are then used to obtain gradients. Although this black-box approach has many advantages in shape optimization problems, one must compute mesh sensitivities in order to compute the design sensitivity. In this paper, we present an alternative approach using the PDE sensitivity equation to develop algorithms for computing gradients. This approach has the advantage that mesh sensitivities need not be computed. Moreover, when it is possible to use the CFD scheme for both the forward problem and the sensitivity equation, then there are computational advantages. An apparent disadvantage of this approach is that it does not always produce consistent derivatives. However, for a proper combination of discretization schemes, one can show asymptotic consistency under mesh refinement, which is often sufficient to guarantee convergence of the optimal design algorithm. In particular, we show that when asymptotically consistent schemes are combined with a trust-region optimization algorithm, the resulting optimal design method converges. We denote this approach as the sensitivity equation method. The sensitivity equation method is presented, convergence results are given and the approach is illustrated on two optimal design problems involving shocks.
Taguchi method of experimental design in materials education
NASA Technical Reports Server (NTRS)
Weiser, Martin W.
1993-01-01
Some of the advantages and disadvantages of the Taguchi Method of experimental design as applied to Materials Science will be discussed. This is a fractional factorial method that employs the minimum number of experimental trials for the information obtained. The analysis is also very simple to use and teach, which is quite advantageous in the classroom. In addition, the Taguchi loss function can be easily incorporated to emphasize that improvements in reproducibility are often at least as important as optimization of the response. The disadvantages of the Taguchi Method include the fact that factor interactions are normally not accounted for, there are zero degrees of freedom if all of the possible factors are used, and randomization is normally not used to prevent environmental biasing. In spite of these disadvantages it is felt that the Taguchi Method is extremely useful for both teaching experimental design and as a research tool, as will be shown with a number of brief examples.
Function combined method for design innovation of children's bike
NASA Astrophysics Data System (ADS)
Wu, Xiaoli; Qiu, Tingting; Chen, Huijuan
2013-03-01
As children mature, bike products for children in the market develop at the same time, and the conditions are frequently updated. Certain problems occur when using a bike, such as cycle overlapping, repeating function, and short life cycle, which go against the principles of energy conservation and the environmental protection intensive design concept. In this paper, a rational multi-function method of design through functional superposition, transformation, and technical implementation is proposed. An organic combination of frog-style scooter and children's tricycle is developed using the multi-function method. From the ergonomic perspective, the paper elaborates on the body size of children aged 5 to 12 and effectively extracts data for a multi-function children's bike, which can be used for gliding and riding. By inverting the body, parts can be interchanged between the handles and the pedals of the bike. Finally, the paper provides a detailed analysis of the components and structural design, body material, and processing technology of the bike. The study of Industrial Product Innovation Design provides an effective design method to solve the bicycle problems, extends the function problems, improves the product market situation, and enhances the energy saving feature while implementing intensive product development effectively at the same time.
Novel kind of DSP design method based on IP core
NASA Astrophysics Data System (ADS)
Yu, Qiaoyan; Liu, Peng; Wang, Weidong; Hong, Xiang; Chen, Jicheng; Yuan, Jianzhong; Chen, Keming
2004-04-01
With the pressure from the design productivity and various special applications, original design method for DSP can no longer keep up with the required speed. A novel design method is needed urgently. Intellectual Property (IP) reusing is a tendency for DSP design, but simple plug-and-play IP cores approaches almost never work. Therefore, appropriate control strategies are needed to connect all the IP cores used and coordinate the whole DSP. This paper presents a new DSP design procedure, which refers to System-on-a-chip, and later introduces a novel control strategy named DWC to implement the DSP based on IP cores. The most important part of this novel control strategy, pipeline control unit (PCU), is given in detail. Because a great number of data hazards occur in most computation-intensive scientific application, a new effective algorithm of checking data hazards is employed in PCU. Following this strategy, the design of a general or special purposed DSP can be finished in shorter time, and the DSP has a potency to improve performance with little modification on basic function units. This DWC strategy has been implement in a 16-bit fixed-pointed DSP successfully.
System Synthesis in Preliminary Aircraft Design using Statistical Methods
NASA Technical Reports Server (NTRS)
DeLaurentis, Daniel; Mavris, Dimitri N.; Schrage, Daniel P.
1996-01-01
This paper documents an approach to conceptual and preliminary aircraft design in which system synthesis is achieved using statistical methods, specifically design of experiments (DOE) and response surface methodology (RSM). These methods are employed in order to more efficiently search the design space for optimum configurations. In particular, a methodology incorporating three uses of these techniques is presented. First, response surface equations are formed which represent aerodynamic analyses, in the form of regression polynomials, which are more sophisticated than generally available in early design stages. Next, a regression equation for an overall evaluation criterion is constructed for the purpose of constrained optimization at the system level. This optimization, though achieved in a innovative way, is still traditional in that it is a point design solution. The methodology put forward here remedies this by introducing uncertainty into the problem, resulting a solutions which are probabilistic in nature. DOE/RSM is used for the third time in this setting. The process is demonstrated through a detailed aero-propulsion optimization of a high speed civil transport. Fundamental goals of the methodology, then, are to introduce higher fidelity disciplinary analyses to the conceptual aircraft synthesis and provide a roadmap for transitioning from point solutions to probabalistic designs (and eventually robust ones).
A Simple Method for High-Lift Propeller Conceptual Design
NASA Technical Reports Server (NTRS)
Patterson, Michael; Borer, Nick; German, Brian
2016-01-01
In this paper, we present a simple method for designing propellers that are placed upstream of the leading edge of a wing in order to augment lift. Because the primary purpose of these "high-lift propellers" is to increase lift rather than produce thrust, these props are best viewed as a form of high-lift device; consequently, they should be designed differently than traditional propellers. We present a theory that describes how these props can be designed to provide a relatively uniform axial velocity increase, which is hypothesized to be advantageous for lift augmentation based on a literature survey. Computational modeling indicates that such propellers can generate the same average induced axial velocity while consuming less power and producing less thrust than conventional propeller designs. For an example problem based on specifications for NASA's Scalable Convergent Electric Propulsion Technology and Operations Research (SCEPTOR) flight demonstrator, a propeller designed with the new method requires approximately 15% less power and produces approximately 11% less thrust than one designed for minimum induced loss. Higher-order modeling and/or wind tunnel testing are needed to verify the predicted performance.
System Synthesis in Preliminary Aircraft Design Using Statistical Methods
NASA Technical Reports Server (NTRS)
DeLaurentis, Daniel; Mavris, Dimitri N.; Schrage, Daniel P.
1996-01-01
This paper documents an approach to conceptual and early preliminary aircraft design in which system synthesis is achieved using statistical methods, specifically Design of Experiments (DOE) and Response Surface Methodology (RSM). These methods are employed in order to more efficiently search the design space for optimum configurations. In particular, a methodology incorporating three uses of these techniques is presented. First, response surface equations are formed which represent aerodynamic analyses, in the form of regression polynomials, which are more sophisticated than generally available in early design stages. Next, a regression equation for an Overall Evaluation Criterion is constructed for the purpose of constrained optimization at the system level. This optimization, though achieved in an innovative way, is still traditional in that it is a point design solution. The methodology put forward here remedies this by introducing uncertainty into the problem, resulting in solutions which are probabilistic in nature. DOE/RSM is used for the third time in this setting. The process is demonstrated through a detailed aero-propulsion optimization of a High Speed Civil Transport. Fundamental goals of the methodology, then, are to introduce higher fidelity disciplinary analyses to the conceptual aircraft synthesis and provide a roadmap for transitioning from point solutions to probabilistic designs (and eventually robust ones).
New displacement-based methods for optimal truss topology design
NASA Technical Reports Server (NTRS)
Bendsoe, Martin P.; Ben-Tal, Aharon; Haftka, Raphael T.
1991-01-01
Two alternate methods for maximum stiffness truss topology design are presented. The ground structure approach is used, and the problem is formulated in terms of displacements and bar areas. This large, nonconvex optimization problem can be solved by a simultaneous analysis and design approach. Alternatively, an equivalent, unconstrained, and convex problem in the displacements only can be formulated, and this problem can be solved by a nonsmooth, steepest descent algorithm. In both methods, the explicit solving of the equilibrium equations and the assembly of the global stiffness matrix are circumvented. A large number of examples have been studied, showing the attractive features of topology design as well as exposing interesting features of optimal topologies.
New Methods and Transducer Designs for Ultrasonic Diagnostics and Therapy
NASA Astrophysics Data System (ADS)
Rybyanets, A. N.; Naumenko, A. A.; Sapozhnikov, O. A.; Khokhlova, V. A.
Recent advances in the field of physical acoustics, imaging technologies, piezoelectric materials, and ultrasonic transducer design have led to emerging of novel methods and apparatus for ultrasonic diagnostics, therapy and body aesthetics. The paper presents the results on development and experimental study of different high intensity focused ultrasound (HIFU) transducers. Technological peculiarities of the HIFU transducer design as well as theoretical and numerical models of such transducers and the corresponding HIFU fields are discussed. Several HIFU transducers of different design have been fabricated using different advanced piezoelectric materials. Acoustic field measurements for those transducers have been performed using a calibrated fiber optic hydrophone and an ultrasonic measurement system (UMS). The results of ex vivo experiments with different tissues as well as in vivo experiments with blood vessels are presented that prove the efficacy, safety and selectivity of the developed HIFU transducers and methods.
Using Propensity Score Methods to Approximate Factorial Experimental Designs
ERIC Educational Resources Information Center
Dong, Nianbo
2011-01-01
The purpose of this study is through Monte Carlo simulation to compare several propensity score methods in approximating factorial experimental design and identify best approaches in reducing bias and mean square error of parameter estimates of the main and interaction effects of two factors. Previous studies focused more on unbiased estimates of…
Impact design methods for ceramic components in gas turbine engines
NASA Technical Reports Server (NTRS)
Song, J.; Cuccio, J.; Kington, H.
1991-01-01
Methods currently under development to design ceramic turbine components with improved impact resistance are presented. Two different modes of impact damage are identified and characterized, i.e., structural damage and local damage. The entire computation is incorporated into the EPIC computer code. Model capability is demonstrated by simulating instrumented plate impact and particle impact tests.
Analytical methods of electrode design for a relativistic electron gun
Caporaso, G.J.; Cole, A.G.; Boyd, J.K.
1985-05-09
The standard paraxial ray equation method for the design of electrodes for an electrostatically focused gun is extended to include relativistic effects and the effects of the beam's azimuthal magnetic field. Solutions for parallel and converging beams are obtained and the predicted currents are compared against those measured on the High Brightness Test Stand. 4 refs., 2 figs.
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…
14 CFR 161.9 - Designation of noise description methods.
Code of Federal Regulations, 2013 CFR
2013-01-01
... and methods prescribed under appendix A of 14 CFR part 150; and (b) Use of computer models to create noise contours must be in accordance with the criteria prescribed under appendix A of 14 CFR part 150. ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Designation of noise description...
14 CFR 161.9 - Designation of noise description methods.
Code of Federal Regulations, 2011 CFR
2011-01-01
... and methods prescribed under appendix A of 14 CFR part 150; and (b) Use of computer models to create noise contours must be in accordance with the criteria prescribed under appendix A of 14 CFR part 150. ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Designation of noise description...
14 CFR 161.9 - Designation of noise description methods.
Code of Federal Regulations, 2012 CFR
2012-01-01
... and methods prescribed under appendix A of 14 CFR part 150; and (b) Use of computer models to create noise contours must be in accordance with the criteria prescribed under appendix A of 14 CFR part 150. ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Designation of noise description...
Comparison of optimal design methods in inverse problems
NASA Astrophysics Data System (ADS)
Banks, H. T.; Holm, K.; Kappel, F.
2011-07-01
Typical optimal design methods for inverse or parameter estimation problems are designed to choose optimal sampling distributions through minimization of a specific cost function related to the resulting error in parameter estimates. It is hoped that the inverse problem will produce parameter estimates with increased accuracy using data collected according to the optimal sampling distribution. Here we formulate the classical optimal design problem in the context of general optimization problems over distributions of sampling times. We present a new Prohorov metric-based theoretical framework that permits one to treat succinctly and rigorously any optimal design criteria based on the Fisher information matrix. A fundamental approximation theory is also included in this framework. A new optimal design, SE-optimal design (standard error optimal design), is then introduced in the context of this framework. We compare this new design criterion with the more traditional D-optimal and E-optimal designs. The optimal sampling distributions from each design are used to compute and compare standard errors; the standard errors for parameters are computed using asymptotic theory or bootstrapping and the optimal mesh. We use three examples to illustrate ideas: the Verhulst-Pearl logistic population model (Banks H T and Tran H T 2009 Mathematical and Experimental Modeling of Physical and Biological Processes (Boca Raton, FL: Chapman and Hall/CRC)), the standard harmonic oscillator model (Banks H T and Tran H T 2009) and a popular glucose regulation model (Bergman R N, Ider Y Z, Bowden C R and Cobelli C 1979 Am. J. Physiol. 236 E667-77 De Gaetano A and Arino O 2000 J. Math. Biol. 40 136-68 Toffolo G, Bergman R N, Finegood D T, Bowden C R and Cobelli C 1980 Diabetes 29 979-90).
Polypharmacology: in silico methods of ligand design and development.
McKie, Samuel A
2016-04-01
How to design a ligand to bind multiple targets, rather than to a single target, is the focus of this review. Rational polypharmacology draws on knowledge that is both broad ranging and hierarchical. Computer-aided multitarget ligand design methods are described according to their nested knowledge level. Ligand-only and then receptor-ligand strategies are first described; followed by the metabolic network viewpoint. Subsequently strategies that view infectious diseases as multigenomic targets are discussed, and finally the disease level interpretation of medicinal therapy is considered. As yet there is no consensus on how best to proceed in designing a multitarget ligand. The current methodologies are bought together in an attempt to give a practical overview of how polypharmacology design might be best initiated. PMID:27105127
Guidance for using mixed methods design in nursing practice research.
Chiang-Hanisko, Lenny; Newman, David; Dyess, Susan; Piyakong, Duangporn; Liehr, Patricia
2016-08-01
The mixed methods approach purposefully combines both quantitative and qualitative techniques, enabling a multi-faceted understanding of nursing phenomena. The purpose of this article is to introduce three mixed methods designs (parallel; sequential; conversion) and highlight interpretive processes that occur with the synthesis of qualitative and quantitative findings. Real world examples of research studies conducted by the authors will demonstrate the processes leading to the merger of data. The examples include: research questions; data collection procedures and analysis with a focus on synthesizing findings. Based on experience with mixed methods studied, the authors introduce two synthesis patterns (complementary; contrasting), considering application for practice and implications for research. PMID:27397810
Computational methods for aerodynamic design using numerical optimization
NASA Technical Reports Server (NTRS)
Peeters, M. F.
1983-01-01
Five methods to increase the computational efficiency of aerodynamic design using numerical optimization, by reducing the computer time required to perform gradient calculations, are examined. The most promising method consists of drastically reducing the size of the computational domain on which aerodynamic calculations are made during gradient calculations. Since a gradient calculation requires the solution of the flow about an airfoil whose geometry was slightly perturbed from a base airfoil, the flow about the base airfoil is used to determine boundary conditions on the reduced computational domain. This method worked well in subcritical flow.
A robust inverse inviscid method for airfoil design
NASA Astrophysics Data System (ADS)
Chaviaropoulos, P.; Dedoussis, V.; Papailiou, K. D.
An irrotational inviscid compressible inverse design method for two-dimensional airfoil profiles is described. The method is based on the potential streamfunction formulation, where the physical space on which the boundaries of the airfoil are sought, is mapped onto the (phi, psi) space via a body-fitted coordinate transformation. A novel procedure based on differential geometry arguments is employed to derive the governing equations for the inverse problem, by requiring the curvature of the flat 2-D Euclidean space to be zero. An auxiliary coordinate transformation permits the definition of C-type computational grids on the (phi, psi) plane resulting to a more accurate description of the leading edge region. Geometry is determined by integrating Frenet equations along the grid lines. To validate the method inverse calculation results are compared to direct, `reproduction', calculation results. The design procedure of a new airfoil shape is also presented.
ERIC Educational Resources Information Center
Collins, Kathleen M. T.; Onwuegbuzie, Anthony J.; Jiao, Qun G.
2007-01-01
A sequential design utilizing identical samples was used to classify mixed methods studies via a two-dimensional model, wherein sampling designs were grouped according to the time orientation of each study's components and the relationship of the qualitative and quantitative samples. A quantitative analysis of 121 studies representing nine fields…
NASA Astrophysics Data System (ADS)
Li, Jingyuan; Michael, Holly A.; Duke, Joshua M.; Messer, Kent D.; Suter, Jordan F.
2014-08-01
This paper assesses the effectiveness of aquifer monitoring information in achieving more sustainable use of a groundwater resource in the absence of management policy. Groundwater user behavior in the face of an irreversible contamination threat is studied by applying methods of experimental economics to scenarios that combine a physics-based, spatially explicit, numerical groundwater model with different representations of information about an aquifer and its risk of contamination. The results suggest that the threat of catastrophic contamination affects pumping decisions: pumping is significantly reduced in experiments where contamination is possible compared to those where pumping cost is the only factor discouraging groundwater use. The level of information about the state of the aquifer also affects extraction behavior. Pumping rates differ when information that synthesizes data on aquifer conditions (a "risk gauge") is provided, despite invariant underlying economic incentives, and this result does not depend on whether the risk information is location-specific or from a whole aquifer perspective. Interestingly, users increase pumping when the risk gauge signals good aquifer status compared to a no-gauge treatment. When the gauge suggests impending contamination, however, pumping declines significantly, resulting in a lower probability of contamination. The study suggests that providing relatively simple aquifer condition guidance derived from monitoring data can lead to more sustainable use of groundwater resources.
Tuning Parameters in Heuristics by Using Design of Experiments Methods
NASA Technical Reports Server (NTRS)
Arin, Arif; Rabadi, Ghaith; Unal, Resit
2010-01-01
With the growing complexity of today's large scale problems, it has become more difficult to find optimal solutions by using exact mathematical methods. The need to find near-optimal solutions in an acceptable time frame requires heuristic approaches. In many cases, however, most heuristics have several parameters that need to be "tuned" before they can reach good results. The problem then turns into "finding best parameter setting" for the heuristics to solve the problems efficiently and timely. One-Factor-At-a-Time (OFAT) approach for parameter tuning neglects the interactions between parameters. Design of Experiments (DOE) tools can be instead employed to tune the parameters more effectively. In this paper, we seek the best parameter setting for a Genetic Algorithm (GA) to solve the single machine total weighted tardiness problem in which n jobs must be scheduled on a single machine without preemption, and the objective is to minimize the total weighted tardiness. Benchmark instances for the problem are available in the literature. To fine tune the GA parameters in the most efficient way, we compare multiple DOE models including 2-level (2k ) full factorial design, orthogonal array design, central composite design, D-optimal design and signal-to-noise (SIN) ratios. In each DOE method, a mathematical model is created using regression analysis, and solved to obtain the best parameter setting. After verification runs using the tuned parameter setting, the preliminary results for optimal solutions of multiple instances were found efficiently.
Risk informed resource allocation policy: safety can save costs.
Pasman, H J
2000-01-01
During economic doldrums, decision making on investments for safety is even more difficult than it already is when funds are abundant. This paper attempts to offer some guidance. After stating the present challenge to prevention of losses in the process industries, the systematic approach of quantified risk assessment is briefly reviewed and improvements in the methodology are mentioned. In addition, attention is given to the use of a risk matrix to survey a plant and to derive a plan of action. Subsequently, the reduction of risk is reviewed. Measures for prevention, protection, and mitigation are discussed. The organization of safety has become at least as important as technical safety of equipment and standards. It is reflected in the introduction of a safety management system. Furthermore, the design process in a pro-active approach is described and the concept of inherent safety is briefly addressed. The concept of Layer of Protection Analysis is explained and also the reason why it is relevant to provide a cost-benefit analysis. Finally, after comments regarding the cost of accidents, the basics of costing and profitability are summarized and a way is suggested to apply this approach to risk-reducing measures. An example is provided on how a selection can be made from a number of alternatives. PMID:10677670
Non-Contact Electromagnetic Exciter Design with Linear Control Method
NASA Astrophysics Data System (ADS)
Wang, Lin; Xiong, Xianzhi; Xu, Hua
2016-04-01
A non-contact type force actuator is necessary for studying the dynamic performance of a high-speed spindle system owing to its high-speed operating conditions. A non-contact electromagnetic exciter is designed for identifying the dynamic coefficients of journal bearings in high-speed grinding spindles. A linear force control method is developed based on PID controller. The influence of amplitude and frequency of current, misalignment and rotational speed on magnetic field and excitation force is investigated based on two-dimensional finite element analysis. The electromagnetic excitation force is measured with the auxiliary coils and calibrated by load cells. The design is validated by the experimental results. Theoretical and experimental investigations show that the proposed design can accurately generate linear excitation force with sufficiently large amplitude and higher signal to noise ratio. Moreover, the fluctuations in force amplitude are reduced to a greater extent with the designed linear control method even when the air gap changes due to the rotor vibration at high-speed conditions. Besides, it is possible to apply various types of excitations: constant, synchronous, and non-synchronous excitation forces based on the proposed linear control method. This exciter can be used as linear-force exciting and controlling system for dynamic performance study of different high-speed rotor-bearing systems.
Material Design, Selection, and Manufacturing Methods for System Sustainment
David Sowder, Jim Lula, Curtis Marshall
2010-02-18
This paper describes a material selection and validation process proven to be successful for manufacturing high-reliability long-life product. The National Secure Manufacturing Center business unit of the Kansas City Plant (herein called KCP) designs and manufactures complex electrical and mechanical components used in extreme environments. The material manufacturing heritage is founded in the systems design to manufacturing practices that support the U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA). Material Engineers at KCP work with the systems designers to recommend materials, develop test methods, perform analytical analysis of test data, define cradle to grave needs, present final selection and fielding. The KCP material engineers typically will maintain cost control by utilizing commercial products when possible, but have the resources and to develop and produce unique formulations as necessary. This approach is currently being used to mature technologies to manufacture materials with improved characteristics using nano-composite filler materials that will enhance system design and production. For some products the engineers plan and carry out science-based life-cycle material surveillance processes. Recent examples of the approach include refurbished manufacturing of the high voltage power supplies for cockpit displays in operational aircraft; dry film lubricant application to improve bearing life for guided munitions gyroscope gimbals, ceramic substrate design for electrical circuit manufacturing, and tailored polymeric materials for various systems. The following examples show evidence of KCP concurrent design-to-manufacturing techniques used to achieve system solutions that satisfy or exceed demanding requirements.
Denoising Sparse Images from GRAPPA using the Nullspace Method (DESIGN)
Weller, Daniel S.; Polimeni, Jonathan R.; Grady, Leo; Wald, Lawrence L.; Adalsteinsson, Elfar; Goyal, Vivek K
2011-01-01
To accelerate magnetic resonance imaging using uniformly undersampled (nonrandom) parallel imaging beyond what is achievable with GRAPPA alone, the Denoising of Sparse Images from GRAPPA using the Nullspace method (DESIGN) is developed. The trade-off between denoising and smoothing the GRAPPA solution is studied for different levels of acceleration. Several brain images reconstructed from uniformly undersampled k-space data using DESIGN are compared against reconstructions using existing methods in terms of difference images (a qualitative measure), PSNR, and noise amplification (g-factors) as measured using the pseudo-multiple replica method. Effects of smoothing, including contrast loss, are studied in synthetic phantom data. In the experiments presented, the contrast loss and spatial resolution are competitive with existing methods. Results for several brain images demonstrate significant improvements over GRAPPA at high acceleration factors in denoising performance with limited blurring or smoothing artifacts. In addition, the measured g-factors suggest that DESIGN mitigates noise amplification better than both GRAPPA and L1 SPIR-iT (the latter limited here by uniform undersampling). PMID:22213069
Smokers' sources of e-cigarette awareness and risk information
Wackowski, Olivia A.; Bover Manderski, Michelle T.; Delnevo, Cristine D.
2015-01-01
Introduction Few studies have explored sources of e-cigarette awareness and peoples' e-cigarette information needs, interests, or behaviors. This study contributes to both domains of e-cigarette research. Methods Results are based on a 2014 e-cigarette focused survey of 519 current smokers from a nationally representative research panel. Results Smokers most frequently reported seeing e-cigarettes in stores (86.4%) and used in person (83%). Many (73%) had also heard about e-cigarettes from known users, broadcast media ads (68%), other (print, online) advertisements (71.5%), and/or from the news (60.9%); sources of awareness varied by e-cigarette experience. Most smokers (59.9%) believed e-cigarettes are less harmful than regular cigarettes, a belief attributed to “common sense” (76.4%), the news (39.2%), and advertisements (37.2%). However, 79.5% felt e-cigarette safety information was important. Over one-third said they would turn to a doctor first for e-cigarette safety information, although almost a quarter said they would turn to the Internet or product packaging first. Most (59.6%) ranked doctors as the most trustworthy risk source, and 6.8% had asked a health professional about e-cigarettes. Conclusions Future research should explore the content of e-cigarette information sources, their potential impact, and ways they might be strengthened or changed through regulatory and/or educational efforts. PMID:26576338
Online Guidance Law of Missile Using Multiple Design Point Method
NASA Astrophysics Data System (ADS)
Yamaoka, Seiji; Ueno, Seiya
This paper deals with design procedure of online guidance law for future missiles that are required to have agile maneuverability. For the purpose, the authors propose to mount high power side-thrusters on a missile. The guidance law for such missiles is discussed from a point of view of optimal control theory in this paper. Minimum time problem is solved for the approximated system. It is derived that bang-bang control is optimal input from the necessary conditions of optimal solution. Feedback guidance without iterative calculation is useful for actual systems. Multiple design point method is applied to design feedback gains and feedforward inputs of the guidance law. The numerical results show the good performance of the proposed guidance law.
Himanen, Risto; Julin, Ari; Jänkälä, Kalle; Holmberg, Jan-Erik; Virolainen, Reino
2012-11-01
There are four operating nuclear power plant (NPP) units in Finland. The Teollisuuden Voima (TVO) power company has two 840 MWe BWR units supplied by Asea-Atom at the Olkiluoto site. The Fortum corporation (formerly IVO) has two 500 MWe VVER 440/213 units at the Loviisa site. In addition, a 1600 MWe European Pressurized Water Reactor supplied by AREVA NP (formerly the Framatome ANP--Siemens AG Consortium) is under construction at the Olkiluoto site. Recently, the Finnish Parliament ratified the government Decision in Principle that the utilities' applications to build two new NPP units are in line with the total good of the society. The Finnish utilities, Fenno power company, and TVO company are in progress of qualifying the type of the new nuclear builds. In Finland, risk-informed applications are formally integrated in the regulatory process of NPPs that are already in the early design phase and these are to run through the construction and operation phases all through the entire plant service time. A plant-specific full-scope probabilistic risk assessment (PRA) is required for each NPP. PRAs shall cover internal events, area events (fires, floods), and external events such as harsh weather conditions and seismic events in all operating modes. Special attention is devoted to the use of various risk-informed PRA applications in the licensing of Olkiluoto 3 NPP. PMID:23035957
COMPSIZE - PRELIMINARY DESIGN METHOD FOR FIBER REINFORCED COMPOSITE STRUCTURES
NASA Technical Reports Server (NTRS)
Eastlake, C. N.
1994-01-01
The Composite Structure Preliminary Sizing program, COMPSIZE, is an analytical tool which structural designers can use when doing approximate stress analysis to select or verify preliminary sizing choices for composite structural members. It is useful in the beginning stages of design concept definition, when it is helpful to have quick and convenient approximate stress analysis tools available so that a wide variety of structural configurations can be sketched out and checked for feasibility. At this stage of the design process the stress/strain analysis does not need to be particularly accurate because any configurations tentatively defined as feasible will later be analyzed in detail by stress analysis specialists. The emphasis is on fast, user-friendly methods so that rough but technically sound evaluation of a broad variety of conceptual designs can be accomplished. Analysis equations used are, in most cases, widely known basic structural analysis methods. All the equations used in this program assume elastic deformation only. The default material selection is intermediate strength graphite/epoxy laid up in a quasi-isotropic laminate. A general flat laminate analysis subroutine is included for analyzing arbitrary laminates. However, COMPSIZE should be sufficient for most users to presume a quasi-isotropic layup and use the familiar basic structural analysis methods for isotropic materials, after estimating an appropriate elastic modulus. Homogeneous materials can be analyzed as simplified cases. The COMPSIZE program is written in IBM BASICA. The program format is interactive. It was designed on an IBM Personal Computer operating under DOS with a central memory requirement of approximately 128K. It has been implemented on an IBM compatible with GW-BASIC under DOS 3.2. COMPSIZE was developed in 1985.
National Tuberculosis Genotyping and Surveillance Network: Design and Methods
Braden, Christopher R.; Schable, Barbara A.; Onorato, Ida M.
2002-01-01
The National Tuberculosis Genotyping and Surveillance Network was established in 1996 to perform a 5-year, prospective study of the usefulness of genotyping Mycobacterium tuberculosis isolates to tuberculosis control programs. Seven sentinel sites identified all new cases of tuberculosis, collected information on patients and contacts, and obtained patient isolates. Seven genotyping laboratories performed DNA fingerprinting analysis by the international standard IS6110 method. BioImage Whole Band Analyzer software was used to analyze patterns, and distinct patterns were assigned unique designations. Isolates with six or fewer bands on IS6110 patterns were also spoligotyped. Patient data and genotyping designations were entered in a relational database and merged with selected variables from the national surveillance database. In two related databases, we compiled the results of routine contact investigations and the results of investigations of the relationships of patients who had isolates with matching genotypes. We describe the methods used in the study. PMID:12453342
Optical design and active optics methods in astronomy
NASA Astrophysics Data System (ADS)
Lemaitre, Gerard R.
2013-03-01
Optical designs for astronomy involve implementation of active optics and adaptive optics from X-ray to the infrared. Developments and results of active optics methods for telescopes, spectrographs and coronagraph planet finders are presented. The high accuracy and remarkable smoothness of surfaces generated by active optics methods also allow elaborating new optical design types with high aspheric and/or non-axisymmetric surfaces. Depending on the goal and performance requested for a deformable optical surface analytical investigations are carried out with one of the various facets of elasticity theory: small deformation thin plate theory, large deformation thin plate theory, shallow spherical shell theory, weakly conical shell theory. The resulting thickness distribution and associated bending force boundaries can be refined further with finite element analysis.
Simplified Analysis Methods for Primary Load Designs at Elevated Temperatures
Carter, Peter; Jetter, Robert I; Sham, Sam
2011-01-01
The use of simplified (reference stress) analysis methods is discussed and illustrated for primary load high temperature design. Elastic methods are the basis of the ASME Section III, Subsection NH primary load design procedure. There are practical drawbacks with this approach, particularly for complex geometries and temperature gradients. The paper describes an approach which addresses these difficulties through the use of temperature-dependent elastic-perfectly plastic analysis. Correction factors are defined to address difficulties traditionally associated with discontinuity stresses, inelastic strain concentrations and multiaxiality. A procedure is identified to provide insight into how this approach could be implemented but clearly there is additional work to be done to define and clarify the procedural steps to bring it to the point where it could be adapted into code language.
Numerical design method for thermally loaded plate-cylinder intersections
Baldur, R.; Laberge, C.A.; Lapointe, D. )
1988-11-01
This paper is an extension of work on stresses in corner radii described by the authors previously. Whereas the original study concerned itself with pressure effects only and the second reference gave the initial version of the work dealing with the thermal effects, this report gives more recent results concerning specifically thermal loads. As before, the results are limited to inside corner radii between cylinders and flat heat closures. Similarly, the analysis is based on a systematic series of finite element calculations with the significant parameters covering the field of useful design boundaries. The results are condensed into a rapid method for the determination of peak stresses needed for performing fatigue analysis in pressure vessels subjected to a significant, variable thermal load. The paper takes into account the influence of the film coefficient, temporal temperature variations, and material properties. A set of coefficients provides a convenient method of stress evaluation suitable for design purposes.
Preliminary demonstration of a robust controller design method
NASA Technical Reports Server (NTRS)
Anderson, L. R.
1980-01-01
Alternative computational procedures for obtaining a feedback control law which yields a control signal based on measurable quantitites are evaluated. The three methods evaluated are: (1) the standard linear quadratic regulator design model; (2) minimization of the norm of the feedback matrix, k via nonlinear programming subject to the constraint that the closed loop eigenvalues be in a specified domain in the complex plane; and (3) maximize the angles between the closed loop eigenvectors in combination with minimizing the norm of K also via the constrained nonlinear programming. The third or robust design method was chosen to yield a closed loop system whose eigenvalues are insensitive to small changes in the A and B matrices. The relationship between orthogonality of closed loop eigenvectors and the sensitivity of closed loop eigenvalues is described. Computer programs are described.
Helicopter flight-control design using an H(2) method
NASA Technical Reports Server (NTRS)
Takahashi, Marc D.
1991-01-01
Rate-command and attitude-command flight-control designs for a UH-60 helicopter in hover are presented and were synthesized using an H(2) method. Using weight functions, this method allows the direct shaping of the singular values of the sensitivity, complementary sensitivity, and control input transfer-function matrices to give acceptable feedback properties. The designs were implemented on the Vertical Motion Simulator, and four low-speed hover tasks were used to evaluate the control system characteristics. The pilot comments from the accel-decel, bob-up, hovering turn, and side-step tasks indicated good decoupling and quick response characteristics. However, an underlying roll PIO tendency was found to exist away from the hover condition, which was caused by a flap regressing mode with insufficient damping.
A Requirements-Driven Optimization Method for Acoustic Treatment Design
NASA Technical Reports Server (NTRS)
Berton, Jeffrey J.
2016-01-01
Acoustic treatment designers have long been able to target specific noise sources inside turbofan engines. Facesheet porosity and cavity depth are key design variables of perforate-over-honeycomb liners that determine levels of noise suppression as well as the frequencies at which suppression occurs. Layers of these structures can be combined to create a robust attenuation spectrum that covers a wide range of frequencies. Looking to the future, rapidly-emerging additive manufacturing technologies are enabling new liners with multiple degrees of freedom, and new adaptive liners with variable impedance are showing promise. More than ever, there is greater flexibility and freedom in liner design. Subject to practical considerations, liner design variables may be manipulated to achieve a target attenuation spectrum. But characteristics of the ideal attenuation spectrum can be difficult to know. Many multidisciplinary system effects govern how engine noise sources contribute to community noise. Given a hardwall fan noise source to be suppressed, and using an analytical certification noise model to compute a community noise measure of merit, the optimal attenuation spectrum can be derived using multidisciplinary systems analysis methods. The subject of this paper is an analytical method that derives the ideal target attenuation spectrum that minimizes noise perceived by observers on the ground.
Application of an optimization method to high performance propeller designs
NASA Technical Reports Server (NTRS)
Li, K. C.; Stefko, G. L.
1984-01-01
The application of an optimization method to determine the propeller blade twist distribution which maximizes propeller efficiency is presented. The optimization employs a previously developed method which has been improved to include the effects of blade drag, camber and thickness. Before the optimization portion of the computer code is used, comparisons of calculated propeller efficiencies and power coefficients are made with experimental data for one NACA propeller at Mach numbers in the range of 0.24 to 0.50 and another NACA propeller at a Mach number of 0.71 to validate the propeller aerodynamic analysis portion of the computer code. Then comparisons of calculated propeller efficiencies for the optimized and the original propellers show the benefits of the optimization method in improving propeller performance. This method can be applied to the aerodynamic design of propellers having straight, swept, or nonplanar propeller blades.
Evaluation of Methods for Multidisciplinary Design Optimization (MDO). Part 2
NASA Technical Reports Server (NTRS)
Kodiyalam, Srinivas; Yuan, Charles; Sobieski, Jaroslaw (Technical Monitor)
2000-01-01
A new MDO method, BLISS, and two different variants of the method, BLISS/RS and BLISS/S, have been implemented using iSIGHT's scripting language and evaluated in this report on multidisciplinary problems. All of these methods are based on decomposing a modular system optimization system into several subtasks optimization, that may be executed concurrently, and the system optimization that coordinates the subtasks optimization. The BLISS method and its variants are well suited for exploiting the concurrent processing capabilities in a multiprocessor machine. Several steps, including the local sensitivity analysis, local optimization, response surfaces construction and updates are all ideally suited for concurrent processing. Needless to mention, such algorithms that can effectively exploit the concurrent processing capabilities of the compute servers will be a key requirement for solving large-scale industrial design problems, such as the automotive vehicle problem detailed in Section 3.4.
Synthesis of aircraft structures using integrated design and analysis methods
NASA Technical Reports Server (NTRS)
Sobieszczanski-Sobieski, J.; Goetz, R. C.
1978-01-01
A systematic research is reported to develop and validate methods for structural sizing of an airframe designed with the use of composite materials and active controls. This research program includes procedures for computing aeroelastic loads, static and dynamic aeroelasticity, analysis and synthesis of active controls, and optimization techniques. Development of the methods is concerned with the most effective ways of integrating and sequencing the procedures in order to generate structural sizing and the associated active control system, which is optimal with respect to a given merit function constrained by strength and aeroelasticity requirements.
Design Methods for Load-bearing Elements from Crosslaminated Timber
NASA Astrophysics Data System (ADS)
Vilguts, A.; Serdjuks, D.; Goremikins, V.
2015-11-01
Cross-laminated timber is an environmentally friendly material, which possesses a decreased level of anisotropy in comparison with the solid and glued timber. Cross-laminated timber could be used for load-bearing walls and slabs of multi-storey timber buildings as well as decking structures of pedestrian and road bridges. Design methods of cross-laminated timber elements subjected to bending and compression with bending were considered. The presented methods were experimentally validated and verified by FEM. Two cross-laminated timber slabs were tested at the action of static load. Pine wood was chosen as a board's material. Freely supported beam with the span equal to 1.9 m, which was loaded by the uniformly distributed load, was a design scheme of the considered plates. The width of the plates was equal to 1 m. The considered cross-laminated timber plates were analysed by FEM method. The comparison of stresses acting in the edge fibres of the plate and the maximum vertical displacements shows that both considered methods can be used for engineering calculations. The difference between the results obtained experimentally and analytically is within the limits from 2 to 31%. The difference in results obtained by effective strength and stiffness and transformed sections methods was not significant.
Asymmetric MRI magnet design using a hybrid numerical method.
Zhao, H; Crozier, S; Doddrell, D M
1999-12-01
This paper describes a hybrid numerical method for the design of asymmetric magnetic resonance imaging magnet systems. The problem is formulated as a field synthesis and the desired current density on the surface of a cylinder is first calculated by solving a Fredholm equation of the first kind. Nonlinear optimization methods are then invoked to fit practical magnet coils to the desired current density. The field calculations are performed using a semi-analytical method. A new type of asymmetric magnet is proposed in this work. The asymmetric MRI magnet allows the diameter spherical imaging volume to be positioned close to one end of the magnet. The main advantages of making the magnet asymmetric include the potential to reduce the perception of claustrophobia for the patient, better access to the patient by attending physicians, and the potential for reduced peripheral nerve stimulation due to the gradient coil configuration. The results highlight that the method can be used to obtain an asymmetric MRI magnet structure and a very homogeneous magnetic field over the central imaging volume in clinical systems of approximately 1.2 m in length. Unshielded designs are the focus of this work. This method is flexible and may be applied to magnets of other geometries. PMID:10579958
Development of quality-by-design analytical methods.
Vogt, Frederick G; Kord, Alireza S
2011-03-01
Quality-by-design (QbD) is a systematic approach to drug development, which begins with predefined objectives, and uses science and risk management approaches to gain product and process understanding and ultimately process control. The concept of QbD can be extended to analytical methods. QbD mandates the definition of a goal for the method, and emphasizes thorough evaluation and scouting of alternative methods in a systematic way to obtain optimal method performance. Candidate methods are then carefully assessed in a structured manner for risks, and are challenged to determine if robustness and ruggedness criteria are satisfied. As a result of these studies, the method performance can be understood and improved if necessary, and a control strategy can be defined to manage risk and ensure the method performs as desired when validated and deployed. In this review, the current state of analytical QbD in the industry is detailed with examples of the application of analytical QbD principles to a range of analytical methods, including high-performance liquid chromatography, Karl Fischer titration for moisture content, vibrational spectroscopy for chemical identification, quantitative color measurement, and trace analysis for genotoxic impurities. PMID:21280050
Libration Orbit Mission Design: Applications of Numerical & Dynamical Methods
NASA Technical Reports Server (NTRS)
Bauer, Frank (Technical Monitor); Folta, David; Beckman, Mark
2002-01-01
Sun-Earth libration point orbits serve as excellent locations for scientific investigations. These orbits are often selected to minimize environmental disturbances and maximize observing efficiency. Trajectory design in support of libration orbits is ever more challenging as more complex missions are envisioned in the next decade. Trajectory design software must be further enabled to incorporate better understanding of the libration orbit solution space and thus improve the efficiency and expand the capabilities of current approaches. The Goddard Space Flight Center (GSFC) is currently supporting multiple libration missions. This end-to-end support consists of mission operations, trajectory design, and control. It also includes algorithm and software development. The recently launched Microwave Anisotropy Probe (MAP) and upcoming James Webb Space Telescope (JWST) and Constellation-X missions are examples of the use of improved numerical methods for attaining constrained orbital parameters and controlling their dynamical evolution at the collinear libration points. This paper presents a history of libration point missions, a brief description of the numerical and dynamical design techniques including software used, and a sample of future GSFC mission designs.
Design and implementation of visualization methods for the CHANGES Spatial Decision Support System
NASA Astrophysics Data System (ADS)
Cristal, Irina; van Westen, Cees; Bakker, Wim; Greiving, Stefan
2014-05-01
The CHANGES Spatial Decision Support System (SDSS) is a web-based system aimed for risk assessment and the evaluation of optimal risk reduction alternatives at local level as a decision support tool in long-term natural risk management. The SDSS use multidimensional information, integrating thematic, spatial, temporal and documentary data. The role of visualization in this context becomes of vital importance for efficiently representing each dimension. This multidimensional aspect of the required for the system risk information, combined with the diversity of the end-users imposes the use of sophisticated visualization methods and tools. The key goal of the present work is to exploit efficiently the large amount of data in relation to the needs of the end-user, utilizing proper visualization techniques. Three main tasks have been accomplished for this purpose: categorization of the end-users, the definition of system's modules and the data definition. The graphical representation of the data and the visualization tools were designed to be relevant to the data type and the purpose of the analysis. Depending on the end-users category, each user should have access to different modules of the system and thus, to the proper visualization environment. The technologies used for the development of the visualization component combine the latest and most innovative open source JavaScript frameworks, such as OpenLayers 2.13.1, ExtJS 4 and GeoExt 2. Moreover, the model-view-controller (MVC) pattern is used in order to ensure flexibility of the system at the implementation level. Using the above technologies, the visualization techniques implemented so far offer interactive map navigation, querying and comparison tools. The map comparison tools are of great importance within the SDSS and include the following: swiping tool for comparison of different data of the same location; raster subtraction for comparison of the same phenomena varying in time; linked views for comparison
Towards Robust Designs Via Multiple-Objective Optimization Methods
NASA Technical Reports Server (NTRS)
Man Mohan, Rai
2006-01-01
evolutionary method (DE) is first used to solve a relatively difficult problem in extended surface heat transfer wherein optimal fin geometries are obtained for different safe operating base temperatures. The objective of maximizing the safe operating base temperature range is in direct conflict with the objective of maximizing fin heat transfer. This problem is a good example of achieving robustness in the context of changing operating conditions. The evolutionary method is then used to design a turbine airfoil; the two objectives being reduced sensitivity of the pressure distribution to small changes in the airfoil shape and the maximization of the trailing edge wedge angle with the consequent increase in airfoil thickness and strength. This is a relevant example of achieving robustness to manufacturing tolerances and wear and tear in the presence of other objectives.
Robert W Youngblood
2010-09-01
The Risk-Informed Safety Margin Characterization (RISMC) pathway is a set of activities defined under the U.S. Department of Energy (DOE) Light Water Reactor Sustainability Program. The overarching objective of RISMC is to support plant life-extension decision-making by providing a state-of-knowledge characterization of safety margins in key systems, structures, and components (SSCs). A technical challenge at the core of this effort is to establish the conceptual and technical feasibility of analyzing safety margin in a risk-informed way, which, unlike conventionally defined deterministic margin analysis, is founded on probabilistic characterizations of SSC performance.
Examining trust factors in online food risk information: The case of unpasteurized or 'raw' milk.
Sillence, Elizabeth; Hardy, Claire; Medeiros, Lydia C; LeJeune, Jeffrey T
2016-04-01
The internet has become an increasingly important way of communicating with consumers about food risk information. However, relatively little is known about how consumers evaluate and come to trust the information they encounter online. Using the example of unpasteurized or raw milk this paper presents two studies exploring the trust factors associated with online information about the risks and benefits of raw milk consumption. In the first study, eye-tracking data was collected from 33 pasteurised milk consumers whilst they viewed six different milk related websites. A descriptive analysis of the eye-tracking data was conducted to explore viewing patterns. Reports revealed the importance of images as a way of capturing initial attention and foregrounding other features and highlighted the significance of introductory text within a homepage. In the second, qualitative study, 41 consumers, some of whom drank raw milk, viewed a selection of milk related websites before participating in either a group discussion or interview. Seventeen of the participants also took part in a follow up telephone interview 2 weeks later. The qualitative data supports the importance of good design whilst noting that balance, authorship agenda, the nature of evidence and personal relevance were also key factors affecting consumers trust judgements. The results of both studies provide support for a staged approach to online trust in which consumers engage in a more rapid, heuristic assessment of a site before moving on to a more in-depth evaluation of the information available. Findings are discussed in relation to the development of trustworthy online food safety resources. PMID:26792772
Methods of compliance evaluation for ocean outfall design and analysis.
Mukhtasor; Lye, L M; Sharp, J J
2002-10-01
Sewage discharge from an ocean outfall is subject to water quality standards, which are often stated in probabilistic terms. Monte Carlo simulation (MCS) has been used in the past to evaluate the ability of a designed outfall to meet water quality standards or compliance guidelines associated with sewage discharges. In this study, simpler and less computer-intensive probabilistic methods are considered. The probabilistic methods evaluated are the popular mean first-order second-moment (MFOSM) and the advance first-order second-moment (AFOSM) methods. Available data from the Spaniard's Bay Outfall located on the east coast of New-foundland, Canada, were used as inputs for a case study. Both methods were compared with results given by MCS. It was found that AFOSM gave a good approximation of the failure probability for total coliform concentration at points remote from the outfall. However, MFOSM was found to be better when considering only the initial dilutions between the discharge point and the surface. Reasons for the different results may be the difference in complexity of the performance function in both cases. This study does not recommend the use of AFOSM for failure analysis in ocean outfall design and analysis because the analysis requires computational efforts similar to MCS. With the advancement of computer technology, simulation techniques, available software, and its flexibility in handling complex situations, MCS is still the best choice for failure analysis of ocean outfalls when data or estimates on the parameters involved are available or can be assumed. PMID:12481920
Improved Method of Design for Folding Inflatable Shells
NASA Technical Reports Server (NTRS)
Johnson, Christopher J.
2009-01-01
An improved method of designing complexly shaped inflatable shells to be assembled from gores was conceived for original application to the inflatable outer shell of a developmental habitable spacecraft module having a cylindrical mid-length section with toroidal end caps. The method is also applicable to inflatable shells of various shapes for terrestrial use. The method addresses problems associated with the assembly, folding, transport, and deployment of inflatable shells that may comprise multiple layers and have complex shapes that can include such doubly curved surfaces as toroids and spheres. One particularly difficult problem is that of mathematically defining fold lines on a gore pattern in a double- curvature region. Moreover, because the fold lines in a double-curvature region tend to be curved, there is a practical problem of how to implement the folds. Another problem is that of modifying the basic gore shapes and sizes for the various layers so that when they are folded as part of the integral structure, they do not mechanically interfere with each other at the fold lines. Heretofore, it has been a common practice to design an inflatable shell to be assembled in the deployed configuration, without regard for the need to fold it into compact form. Typically, the result has been that folding has been a difficult, time-consuming process resulting in a An improved method of designing complexly shaped inflatable shells to be assembled from gores was conceived for original application to the inflatable outer shell of a developmental habitable spacecraft module having a cylindrical mid-length section with toroidal end caps. The method is also applicable to inflatable shells of various shapes for terrestrial use. The method addresses problems associated with the assembly, folding, transport, and deployment of inflatable shells that may comprise multiple layers and have complex shapes that can include such doubly curved surfaces as toroids and spheres. One
A geometric design method for side-stream distillation columns
Rooks, R.E.; Malone, M.F.; Doherty, M.F.
1996-10-01
A side-stream distillation column may replace two simple columns for some applications, sometimes at considerable savings in energy and investment. This paper describes a geometric method for the design of side-stream columns; the method provides rapid estimates of equipment size and utility requirements. Unlike previous approaches, the geometric method is applicable to nonideal and azeotropic mixtures. Several example problems for both ideal and nonideal mixtures, including azeotropic mixtures containing distillation boundaries, are given. The authors make use of the fact that azeotropes or pure components whose classification in the residue curve map is a saddle can be removed as side-stream products. Significant process simplifications are found among some alternatives in example problems, leading to flow sheets with fewer units and a substantial savings in vapor rate.
Sequence design in lattice models by graph theoretical methods
NASA Astrophysics Data System (ADS)
Sanjeev, B. S.; Patra, S. M.; Vishveshwara, S.
2001-01-01
A general strategy has been developed based on graph theoretical methods, for finding amino acid sequences that take up a desired conformation as the native state. This problem of inverse design has been addressed by assigning topological indices for the monomer sites (vertices) of the polymer on a 3×3×3 cubic lattice. This is a simple design strategy, which takes into account only the topology of the target protein and identifies the best sequence for a given composition. The procedure allows the design of a good sequence for a target native state by assigning weights for the vertices on a lattice site in a given conformation. It is seen across a variety of conformations that the predicted sequences perform well both in sequence and in conformation space, in identifying the target conformation as native state for a fixed composition of amino acids. Although the method is tested in the framework of the HP model [K. F. Lau and K. A. Dill, Macromolecules 22, 3986 (1989)] it can be used in any context if proper potential functions are available, since the procedure derives unique weights for all the sites (vertices, nodes) of the polymer chain of a chosen conformation (graph).
D. P. Blanchard; R. W. Youngblood
2014-06-01
The Risk-Informed Safety Margin Characterization (RISMC) pathway of the DOE’s Light Water Reactor Sustainability (LWRS) program focuses on advancing the state of the art in safety analysis and risk assessment to support decision-making on nuclear power plant operation well beyond the originally designed lifetime of the plants (i.e., beyond 60 years). Among the issues being addressed in RISMC is the significance of SSC aging and how confident we are about our understanding of its impact on the margin between the loads SSCs are expected to see during normal operation and accident conditions, and the SSC capacities (their ability to resist those loads) as the SSCs age. In this paper, a summary is provided of a case study that examines SSC aging from an environmental qualification (EQ) perspective. The case study illustrates how the state of knowledge regarding SSC margin can be characterized given the overall integrated plant design, and was developed to demonstrate a method for deciding on which cables to focus, which cables are not so important from an environmental qualification margin standpoint, and what plant design features or operating characteristics determine the role that environmental qualification plays in establishing a safety case on which decisions regarding margin can be made. The selection of cables for which demonstration of margin with respect to aging and environmental challenges uses a technique known as Prevention Analysis. Prevention Analysis is a Boolean method for optimal selection of SSCs (that is, those combinations of SSCs both necessary and sufficient to meet a predetermined selection criterion) in a manner that allows demonstration that plant-level safety can be demonstrated by the collection of selected SSCs alone. Choosing the set of SSCs that is necessary and sufficient to satisfy the safety objectives, and demonstrating that the safety objectives can be met effectively, determines where resources are best allocated to assure SSC
A Probabilistic Design Method Applied to Smart Composite Structures
NASA Technical Reports Server (NTRS)
Shiao, Michael C.; Chamis, Christos C.
1995-01-01
A probabilistic design method is described and demonstrated using a smart composite wing. Probabilistic structural design incorporates naturally occurring uncertainties including those in constituent (fiber/matrix) material properties, fabrication variables, structure geometry and control-related parameters. Probabilistic sensitivity factors are computed to identify those parameters that have a great influence on a specific structural reliability. Two performance criteria are used to demonstrate this design methodology. The first criterion requires that the actuated angle at the wing tip be bounded by upper and lower limits at a specified reliability. The second criterion requires that the probability of ply damage due to random impact load be smaller than an assigned value. When the relationship between reliability improvement and the sensitivity factors is assessed, the results show that a reduction in the scatter of the random variable with the largest sensitivity factor (absolute value) provides the lowest failure probability. An increase in the mean of the random variable with a negative sensitivity factor will reduce the failure probability. Therefore, the design can be improved by controlling or selecting distribution parameters associated with random variables. This can be implemented during the manufacturing process to obtain maximum benefit with minimum alterations.
A geometric method for optimal design of color filter arrays.
Hao, Pengwei; Li, Yan; Lin, Zhouchen; Dubois, Eric
2011-03-01
A color filter array (CFA) used in a digital camera is a mosaic of spectrally selective filters, which allows only one color component to be sensed at each pixel. The missing two components of each pixel have to be estimated by methods known as demosaicking. The demosaicking algorithm and the CFA design are crucial for the quality of the output images. In this paper, we present a CFA design methodology in the frequency domain. The frequency structure, which is shown to be just the symbolic DFT of the CFA pattern (one period of the CFA), is introduced to represent images sampled with any rectangular CFAs in the frequency domain. Based on the frequency structure, the CFA design involves the solution of a constrained optimization problem that aims at minimizing the demosaicking error. To decrease the number of parameters and speed up the parameter searching, the optimization problem is reformulated as the selection of geometric points on the boundary of a convex polygon or the surface of a convex polyhedron. Using our methodology, several new CFA patterns are found, which outperform the currently commercialized and published ones. Experiments demonstrate the effectiveness of our CFA design methodology and the superiority of our new CFA patterns. PMID:20858581
Modified method to improve the design of Petlyuk distillation columns
2014-01-01
Background A response surface analysis was performed to study the effect of the composition and feeding thermal conditions of ternary mixtures on the number of theoretical stages and the energy consumption of Petlyuk columns. A modification of the pre-design algorithm was necessary for this purpose. Results The modified algorithm provided feasible results in 100% of the studied cases, compared with only 8.89% for the current algorithm. The proposed algorithm allowed us to attain the desired separations, despite the type of mixture and the operating conditions in the feed stream, something that was not possible with the traditional pre-design method. The results showed that the type of mixture had great influence on the number of stages and on energy consumption. A higher number of stages and a lower consumption of energy were attained with mixtures rich in the light component, while higher energy consumption occurred when the mixture was rich in the heavy component. Conclusions The proposed strategy expands the search of an optimal design of Petlyuk columns within a feasible region, which allow us to find a feasible design that meets output specifications and low thermal loads. PMID:25061476
Airfoil Design and Optimization by the One-Shot Method
NASA Technical Reports Server (NTRS)
Kuruvila, G.; Taasan, Shlomo; Salas, M. D.
1995-01-01
An efficient numerical approach for the design of optimal aerodynamic shapes is presented in this paper. The objective of any optimization problem is to find the optimum of a cost function subject to a certain state equation (governing equation of the flow field) and certain side constraints. As in classical optimal control methods, the present approach introduces a costate variable (Lagrange multiplier) to evaluate the gradient of the cost function. High efficiency in reaching the optimum solution is achieved by using a multigrid technique and updating the shape in a hierarchical manner such that smooth (low-frequency) changes are done separately from high-frequency changes. Thus, the design variables are changed on a grid where their changes produce nonsmooth (high-frequency) perturbations that can be damped efficiently by the multigrid. The cost of solving the optimization problem is approximately two to three times the cost of the equivalent analysis problem.
A Method for Designing CDO Conformed to Investment Parameters
NASA Astrophysics Data System (ADS)
Nakae, Tatsuya; Moritsu, Toshiyuki; Komoda, Norihisa
We propose a method for designing CDO (Collateralized Debt Obligation) that meets investor needs about attributes of CDO. It is demonstrated that adjusting attributes (that are credit capability and issue amount) of CDO to investors' preferences causes a capital loss risk that the agent takes. We formulate a CDO optimization problem by defining an objective function using the above risk and by setting constraints that arise from investor needs and a risk premium that is paid for the agent. Our prototype experiment, in which fictitious underlying obligations and investor needs are given, verifies that CDOs can be designed without opportunity loss and dead stock loss, and that the capital loss is not more than thousandth part of the amount of annual payment under guarantee for small and midium-sized enterprises by a general credit guarantee institution.
A formal method for early spacecraft design verification
NASA Astrophysics Data System (ADS)
Fischer, P. M.; Ludtke, D.; Schaus, V.; Gerndt, A.
In the early design phase of a spacecraft, various aspects of the system under development are described and modeled using parameters such as masses, power consumption or data rates. In particular power and data parameters are special since their values can change depending on the spacecrafts operational mode. These mode-dependent parameters can be easily verified to static requirements like a maximumdata rate. Such quick verifications allow the engineers to check the design after every change they apply. In contrast, requirements concerning the mission lifetime such as the amount of downlinked data during the whole mission, demands a more complex procedure. We propose an executable model together with a simulation framework to evaluate complex mission scenarios. In conjunction with a formalized specification of mission requirements it allows a quick verification by means of formal methods.
Collocation methods for distillation design. 2: Applications for distillation
Huss, R.S.; Westerberg, A.W.
1996-05-01
The authors present applications for a collocation method for modeling distillation columns that they developed in a companion paper. They discuss implementation of the model, including discussion of the ASCEND (Advanced System for Computations in ENgineering Design) system, which enables one to create complex models with simple building blocks and interactively learn to solve them. They first investigate applying the model to compute minimum reflux for a given separation task, exactly solving nonsharp and approximately solving sharp split minimum reflux problems. They next illustrate the use of the collocation model to optimize the design a single column capable of carrying out a prescribed set of separation tasks. The optimization picks the best column diameter and total number of trays. It also picks the feed tray for each of the prescribed separations.
Statistical Methods for Rapid Aerothermal Analysis and Design Technology: Validation
NASA Technical Reports Server (NTRS)
DePriest, Douglas; Morgan, Carolyn
2003-01-01
The cost and safety goals for NASA s next generation of reusable launch vehicle (RLV) will require that rapid high-fidelity aerothermodynamic design tools be used early in the design cycle. To meet these requirements, it is desirable to identify adequate statistical models that quantify and improve the accuracy, extend the applicability, and enable combined analyses using existing prediction tools. The initial research work focused on establishing suitable candidate models for these purposes. The second phase is focused on assessing the performance of these models to accurately predict the heat rate for a given candidate data set. This validation work compared models and methods that may be useful in predicting the heat rate.
Conceptual Design Method Developed for Advanced Propulsion Nozzles
NASA Technical Reports Server (NTRS)
Nadell, Shari-Beth; Barnhart, Paul J.
1998-01-01
As part of a contract with the NASA Lewis Research Center, a simple, accurate method of predicting the performance characteristics of a nozzle design has been developed for use in conceptual design studies. The Nozzle Performance Analysis Code (NPAC) can predict the on- and off-design performance of axisymmetric or two-dimensional convergent and convergent-divergent nozzle geometries. NPAC accounts for the effects of overexpansion or underexpansion, flow divergence, wall friction, heat transfer, and small mass addition or loss across surfaces when the nozzle gross thrust and gross thrust coefficient are being computed. NPAC can be used to predict the performance of a given nozzle design or to develop a preliminary nozzle system design for subsequent analysis. The input required by NPAC consists of a simple geometry definition of the nozzle surfaces, the location of key nozzle stations (entrance, throat, exit), and the nozzle entrance flow properties. NPAC performs three analysis "passes" on the nozzle geometry. First, an isentropic control volume analysis is performed to determine the gross thrust and gross thrust coefficient of the nozzle. During the second analysis pass, the skin friction and heat transfer losses are computed. The third analysis pass couples the effects of wall shear and heat transfer with the initial internal nozzle flow solutions to produce a system of equations that is solved at steps along the nozzle geometry. Small mass additions or losses, such as those resulting from leakage or bleed flow, can be included in the model at specified geometric sections. A final correction is made to account for divergence losses that are incurred if the nozzle exit flow is not purely axial.
Hardware architecture design of a fast global motion estimation method
NASA Astrophysics Data System (ADS)
Liang, Chaobing; Sang, Hongshi; Shen, Xubang
2015-12-01
VLSI implementation of gradient-based global motion estimation (GME) faces two main challenges: irregular data access and high off-chip memory bandwidth requirement. We previously proposed a fast GME method that reduces computational complexity by choosing certain number of small patches containing corners and using them in a gradient-based framework. A hardware architecture is designed to implement this method and further reduce off-chip memory bandwidth requirement. On-chip memories are used to store coordinates of the corners and template patches, while the Gaussian pyramids of both the template and reference frame are stored in off-chip SDRAMs. By performing geometric transform only on the coordinates of the center pixel of a 3-by-3 patch in the template image, a 5-by-5 area containing the warped 3-by-3 patch in the reference image is extracted from the SDRAMs by burst read. Patched-based and burst mode data access helps to keep the off-chip memory bandwidth requirement at the minimum. Although patch size varies at different pyramid level, all patches are processed in term of 3x3 patches, so the utilization of the patch-processing circuit reaches 100%. FPGA implementation results show that the design utilizes 24,080 bits on-chip memory and for a sequence with resolution of 352x288 and frequency of 60Hz, the off-chip bandwidth requirement is only 3.96Mbyte/s, compared with 243.84Mbyte/s of the original gradient-based GME method. This design can be used in applications like video codec, video stabilization, and super-resolution, where real-time GME is a necessity and minimum memory bandwidth requirement is appreciated.
Design of braided composite tubes by numerical analysis method
Hamada, Hiroyuki; Fujita, Akihiro; Maekawa, Zenichiro; Nakai, Asami; Yokoyama, Atsushi
1995-11-01
Conventional composite laminates have very poor strength through thickness and as a result are limited in their application for structural parts with complex shape. In this paper, the design for braided composite tube was proposed. The concept of analysis model which involved from micro model to macro model was presented. This method was applied to predict bending rigidity and initial fracture stress under bending load of the braided tube. The proposed analytical procedure can be included as a unit in CAE system for braided composites.
Methods to Design and Synthesize Antibody-Drug Conjugates (ADCs)
Yao, Houzong; Jiang, Feng; Lu, Aiping; Zhang, Ge
2016-01-01
Antibody-drug conjugates (ADCs) have become a promising targeted therapy strategy that combines the specificity, favorable pharmacokinetics and biodistributions of antibodies with the destructive potential of highly potent drugs. One of the biggest challenges in the development of ADCs is the application of suitable linkers for conjugating drugs to antibodies. Recently, the design and synthesis of linkers are making great progress. In this review, we present the methods that are currently used to synthesize antibody-drug conjugates by using thiols, amines, alcohols, aldehydes and azides. PMID:26848651
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... COMMISSION Determining Technical Adequacy of Probabilistic Risk Assessment for Risk-Informed License...: LWR Edition,'' Section 19.1, ``Determining the Technical Adequacy of Probabilistic Risk Assessment for...; email: Amy.Cubbage@nrc.gov . SUPPLEMENTARY INFORMATION: On May 22, 2012 (77 FR 30335), the NRC...
ERIC Educational Resources Information Center
Bamberg, Richard; And Others
1990-01-01
Results from a study of 82 males provide no statistical support and limited encouragement that genetic risk information may motivate persons to make positive changes in preventive health behaviors. Health risk assessments were used to identify subjects at risk for coronary heart disease or lung cancer because of genetic factors. (IAH)
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Fault Management in an Objectives-Based/Risk-Informed View of Safety and Mission Success
NASA Technical Reports Server (NTRS)
Groen, Frank
2012-01-01
Theme of this talk: (1) Net-benefit of activities and decisions derives from objectives (and their priority) -- similarly: need for integration, value of technology/capability. (2) Risk is a lack of confidence that objectives will be met. (2a) Risk-informed decision making requires objectives. (3) Consideration of objectives is central to recent guidance.
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2010-10-18
...EPA's IRIS is a human health assessment program that evaluates quantitative and qualitative risk information on effects that may result from exposure to specific chemical substances found in the environment. EPA is soliciting public nominations for chemical substances for its 2011 agenda. EPA invites the public to submit nominations for substances to be considered for an assessment or......
An alternate method for designing dipole magnet ends
Pope, W.L.; Green, M.A.; Peters, C.; Caspi, S.; Taylor, C.E.
1988-08-01
Small bore superconducting dipole magnets, such as those for the SSC, often have problems in the ends. These problems can often be alleviated by spreading out the end windings so that the conductor sees less deformation. This paper presents a new procedure for designing dipole magnet ends which can be applied to magnets with either cylindrical or conical bulged ends to have integrated field multipoles which meet the constraints imposed by the SSC lattice. The method described here permits one to couple existing multiparameter optimization routines (i.e., MINUIT with suitable independent parameter constraints) with a computer code DIPEND, which describes the multiples, so that one can meet any reasonable objective (i.e., minimizing integrated sextupole and decapole). This paper will describe how the computer method was used to analyze the bulged conical ends for an SSC dipole. 6 refs, 6 figs, 2 tabs.
A Method of Trajectory Design for Manned Asteroids Exploration
NASA Astrophysics Data System (ADS)
Gan, Q. B.; Zhang, Y.; Zhu, Z. F.; Han, W. H.; Dong, X.
2014-11-01
A trajectory optimization method of the nuclear propulsion manned asteroids exploration is presented. In the case of launching between 2035 and 2065, based on the Lambert transfer orbit, the phases of departure from and return to the Earth are searched at first. Then the optimal flight trajectory in the feasible regions is selected by pruning the flight sequences. Setting the nuclear propulsion flight plan as propel-coast-propel, and taking the minimal mass of aircraft departure as the index, the nuclear propulsion flight trajectory is separately optimized using a hybrid method. With the initial value of the optimized local parameters of each three phases, the global parameters are jointedly optimized. At last, the minimal departure mass trajectory design result is given.
An FPGA-based heterogeneous image fusion system design method
NASA Astrophysics Data System (ADS)
Song, Le; Lin, Yu-chi; Chen, Yan-hua; Zhao, Mei-rong
2011-08-01
Taking the advantages of FPGA's low cost and compact structure, an FPGA-based heterogeneous image fusion platform is established in this study. Altera's Cyclone IV series FPGA is adopted as the core processor of the platform, and the visible light CCD camera and infrared thermal imager are used as the image-capturing device in order to obtain dualchannel heterogeneous video images. Tailor-made image fusion algorithms such as gray-scale weighted averaging, maximum selection and minimum selection methods are analyzed and compared. VHDL language and the synchronous design method are utilized to perform a reliable RTL-level description. Altera's Quartus II 9.0 software is applied to simulate and implement the algorithm modules. The contrast experiments of various fusion algorithms show that, preferably image quality of the heterogeneous image fusion can be obtained on top of the proposed system. The applied range of the different fusion algorithms is also discussed.
A novel observer design method for neural mass models
NASA Astrophysics Data System (ADS)
Liu, Xian; Miao, Dong-Kai; Gao, Qing; Xu, Shi-Yun
2015-09-01
Neural mass models can simulate the generation of electroencephalography (EEG) signals with different rhythms, and therefore the observation of the states of these models plays a significant role in brain research. The structure of neural mass models is special in that they can be expressed as Lurie systems. The developed techniques in Lurie system theory are applicable to these models. We here provide a new observer design method for neural mass models by transforming these models and the corresponding error systems into nonlinear systems with Lurie form. The purpose is to establish appropriate conditions which ensure the convergence of the estimation error. The effectiveness of the proposed method is illustrated by numerical simulations. Project supported by the National Natural Science Foundation of China (Grant Nos. 61473245, 61004050, and 51207144).
Impact design methods for ceramic components in gas turbine engines
Song, J.; Cuccio, J.; Kington, H. . Garrett Auxilliary Power Division)
1993-01-01
Garrett Auxiliary Power Division of Allied-Signal Aerospace Company is developing methods to design ceramic turbine components with improved impact resistance. In an ongoing research effort under the DOE/NASA-funded Advanced Turbine Technology Applications Project (ATTAP), two different modes of impact damage have been identified and characterized: local damage and structural damage. Local impact damage to Si[sub 3]N[sub 4] impacted by spherical projectiles usually takes the form of ring and/or radial cracks in the vicinity of the impact point. Baseline data from Si[sub 3]N[sub 4] test bars impacted by 1.588-mm (0.0625-in.) diameter NC-132 projectiles indicates the critical velocity at which the probability of detecting surface cracks is 50 percent equaled 130 m/s (426 ft/sec). A microphysics-based model that assumes damage to be in the form of microcracks has been developed to predict local impact damage. Local stress and strain determine microcrack nucleation and propagation, which in turn alter local stress and strain through modulus degradation. Material damage is quantified by a damage parameter related to the volume fraction of microcracks. The entire computation has been incorporated into the EPIC computer code. Model capability is being demonstrated by simulating instrumented plate impact and particle impact tests. Structural impact damage usually occurs in the form of fast fracture caused by bending stresses that exceed the material strength. The EPIC code has been successfully used to predict radial and axial blade failures from impacts by various size particles. This method is also being used in conjunction with Taguchi experimental methods to investigate the effects of design parameters on turbine blade impact resistance. It has been shown that significant improvement in impact resistance can be achieved by using the configuration recommended by Taguchi methods.
Novel computational methods to design protein-protein interactions
NASA Astrophysics Data System (ADS)
Zhou, Alice Qinhua; O'Hern, Corey; Regan, Lynne
2014-03-01
Despite the abundance of structural data, we still cannot accurately predict the structural and energetic changes resulting from mutations at protein interfaces. The inadequacy of current computational approaches to the analysis and design of protein-protein interactions has hampered the development of novel therapeutic and diagnostic agents. In this work, we apply a simple physical model that includes only a minimal set of geometrical constraints, excluded volume, and attractive van der Waals interactions to 1) rank the binding affinity of mutants of tetratricopeptide repeat proteins with their cognate peptides, 2) rank the energetics of binding of small designed proteins to the hydrophobic stem region of the influenza hemagglutinin protein, and 3) predict the stability of T4 lysozyme and staphylococcal nuclease mutants. This work will not only lead to a fundamental understanding of protein-protein interactions, but also to the development of efficient computational methods to rationally design protein interfaces with tunable specificity and affinity, and numerous applications in biomedicine. NSF DMR-1006537, PHY-1019147, Raymond and Beverly Sackler Institute for Biological, Physical and Engineering Sciences, and Howard Hughes Medical Institute.
Sensitivity method for integrated structure/active control law design
NASA Technical Reports Server (NTRS)
Gilbert, Michael G.
1987-01-01
The development is described of an integrated structure/active control law design methodology for aeroelastic aircraft applications. A short motivating introduction to aeroservoelasticity is given along with the need for integrated structures/controls design algorithms. Three alternative approaches to development of an integrated design method are briefly discussed with regards to complexity, coordination and tradeoff strategies, and the nature of the resulting solutions. This leads to the formulation of the proposed approach which is based on the concepts of sensitivity of optimum solutions and multi-level decompositions. The concept of sensitivity of optimum is explained in more detail and compared with traditional sensitivity concepts of classical control theory. The analytical sensitivity expressions for the solution of the linear, quadratic cost, Gaussian (LQG) control problem are summarized in terms of the linear regulator solution and the Kalman Filter solution. Numerical results for a state space aeroelastic model of the DAST ARW-II vehicle are given, showing the changes in aircraft responses to variations of a structural parameter, in this case first wing bending natural frequency.
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...Notice is hereby given that the Environmental Protection Agency (EPA) has designated, in accordance with 40 CFR Part 53, three new equivalent methods: One for measuring concentrations of nitrogen dioxide (NO2) and two for measuring concentrations of lead (Pb) in the ambient...
Simplified design method for shear-valve magnetorheological dampers
NASA Astrophysics Data System (ADS)
Ding, Yang; Zhang, Lu; Zhu, Haitao; Li, Zhongxian
2014-12-01
Based on the Bingham parallel-plate model, a simplified design method of shear-valve magnetorheological (MR) dampers is proposed considering the magnetic circuit optimization. Correspondingly, a new MR damper with a full-length effective damping path is proposed. The prototype dampers are also fabricated and studied numerically and experimentally. According to the test results, the Bingham parallel-plate model is further modified to obtain a damping force prediction model of the proposed MR dampers. This prediction model considers the magnetic saturation phenomenon. The study indicates that the proposed simplified design method is simple, effective and reliable. The maximum damping force of the proposed MR dampers with a full-length effective damping path is at least twice as large as those of conventional MR dampers. The dynamic range of damping force increases by at least 70%. The proposed damping force prediction model considers the magnetic saturation phenomenon and it can realize the actual characteristic of MR fluids. The model is able to predict the actual damping force of MR dampers precisely.
Development of Analysis Methods for Designing with Composites
NASA Technical Reports Server (NTRS)
Madenci, E.
1999-01-01
The project involved the development of new analysis methods to achieve efficient design of composite structures. We developed a complex variational formulation to analyze the in-plane and bending coupling response of an unsymmetrically laminated plate with an elliptical cutout subjected to arbitrary edge loading as shown in Figure 1. This formulation utilizes four independent complex potentials that satisfy the coupled in-plane and bending equilibrium equations, thus eliminating the area integrals from the strain energy expression. The solution to a finite geometry laminate under arbitrary loading is obtained by minimizing the total potential energy function and solving for the unknown coefficients of the complex potentials. The validity of this approach is demonstrated by comparison with finite element analysis predictions for a laminate with an inclined elliptical cutout under bi-axial loading.The geometry and loading of this laminate with a lay-up of [-45/45] are shown in Figure 2. The deformed configuration shown in Figure 3 reflects the presence of bending-stretching coupling. The validity of the present method is established by comparing the out-of-plane deflections along the boundary of the elliptical cutout from the present approach with those of the finite element method. The comparison shown in Figure 4 indicates remarkable agreement. The details of this method are described in a manuscript by Madenci et al. (1998).
A new method of dual FOV optical system design
NASA Astrophysics Data System (ADS)
Zhang, Liang
2009-07-01
With the development of scientific technologies, infrared imaging technology has been applied in the fields of industry, medical treatment, and national defense and so on. Infrared detection has the advantages of looking through the smoke, fog, haze, snow, and also could avoid the affection of battlefield flash. Hence, it could achieve the long distance and all-weather scout, especially in nighttime and badness weather conditions.All kinds of single-FOV, dual-FOV, multi-FOV and continuous zoom optical systems have been applied more and more abroad with the research and application of infrared imaging technologies. Therefore, the research of all sorts of dual FOV optical systems would be more important. The system belongs to simple zoom optical systems by having two fields of view. The zoom methods comprise of single zoom, rotary zoom, radial zoom, axial zoom and so on. Basing on the analysis of zoom methods, a new method of zoom optical system has been developed, which realized the dual FOV optical system by sharing secondary imaging lenses. This design method could make the results approaching to diffraction limit, and improve the precision of optical axial. It also has decreased the moving parts and reduced the difficulty of assembly of system.
A New Aerodynamic Data Dispersion Method for Launch Vehicle Design
NASA Technical Reports Server (NTRS)
Pinier, Jeremy T.
2011-01-01
A novel method for implementing aerodynamic data dispersion analysis is herein introduced. A general mathematical approach combined with physical modeling tailored to the aerodynamic quantity of interest enables the generation of more realistically relevant dispersed data and, in turn, more reasonable flight simulation results. The method simultaneously allows for the aerodynamic quantities and their derivatives to be dispersed given a set of non-arbitrary constraints, which stresses the controls model in more ways than with the traditional bias up or down of the nominal data within the uncertainty bounds. The adoption and implementation of this new method within the NASA Ares I Crew Launch Vehicle Project has resulted in significant increases in predicted roll control authority, and lowered the induced risks for flight test operations. One direct impact on launch vehicles is a reduced size for auxiliary control systems, and the possibility of an increased payload. This technique has the potential of being applied to problems in multiple areas where nominal data together with uncertainties are used to produce simulations using Monte Carlo type random sampling methods. It is recommended that a tailored physics-based dispersion model be delivered with any aerodynamic product that includes nominal data and uncertainties, in order to make flight simulations more realistic and allow for leaner spacecraft designs.
Nanobiological studies on drug design using molecular mechanic method
Ghaheh, Hooria Seyedhosseini; Mousavi, Maryam; Araghi, Mahmood; Rasoolzadeh, Reza; Hosseini, Zahra
2015-01-01
Background: Influenza H1N1 is very important worldwide and point mutations that occur in the virus gene are a threat for the World Health Organization (WHO) and druggists, since they could make this virus resistant to the existing antibiotics. Influenza epidemics cause severe respiratory illness in 30 to 50 million people and kill 250,000 to 500,000 people worldwide every year. Nowadays, drug design is not done through trial and error because of its cost and waste of time; therefore bioinformatics studies is essential for designing drugs. Materials and Methods: This paper, infolds a study on binding site of Neuraminidase (NA) enzyme, (that is very important in drug design) in 310K temperature and different dielectrics, for the best drug design. Information of NA enzyme was extracted from Protein Data Bank (PDB) and National Center for Biotechnology Information (NCBI) websites. The new sequences of N1 were downloaded from the NCBI influenza virus sequence database. Drug binding sites were assimilated and homologized modeling using Argus lab 4.0, HyperChem 6.0 and Chem. D3 softwares. Their stability was assessed in different dielectrics and temperatures. Result: Measurements of potential energy (Kcal/mol) of binding sites of NA in different dielectrics and 310K temperature revealed that at time step size = 0 pSec drug binding sites have maximum energy level and at time step size = 100 pSec have maximum stability and minimum energy. Conclusions: Drug binding sites are more dependent on dielectric constants rather than on temperature and the optimum dielectric constant is 39/78. PMID:26605248
Formal methods in the design of Ada 1995
NASA Technical Reports Server (NTRS)
Guaspari, David
1995-01-01
Formal, mathematical methods are most useful when applied early in the design and implementation of a software system--that, at least, is the familiar refrain. I will report on a modest effort to apply formal methods at the earliest possible stage, namely, in the design of the Ada 95 programming language itself. This talk is an 'experience report' that provides brief case studies illustrating the kinds of problems we worked on, how we approached them, and the extent (if any) to which the results proved useful. It also derives some lessons and suggestions for those undertaking future projects of this kind. Ada 95 is the first revision of the standard for the Ada programming language. The revision began in 1988, when the Ada Joint Programming Office first asked the Ada Board to recommend a plan for revising the Ada standard. The first step in the revision was to solicit criticisms of Ada 83. A set of requirements for the new language standard, based on those criticisms, was published in 1990. A small design team, the Mapping Revision Team (MRT), became exclusively responsible for revising the language standard to satisfy those requirements. The MRT, from Intermetrics, is led by S. Tucker Taft. The work of the MRT was regularly subject to independent review and criticism by a committee of distinguished Reviewers and by several advisory teams--for example, the two User/Implementor teams, each consisting of an industrial user (attempting to make significant use of the new language on a realistic application) and a compiler vendor (undertaking, experimentally, to modify its current implementation in order to provide the necessary new features). One novel decision established the Language Precision Team (LPT), which investigated language proposals from a mathematical point of view. The LPT applied formal mathematical analysis to help improve the design of Ada 95 (e.g., by clarifying the language proposals) and to help promote its acceptance (e.g., by identifying a
Learning physics: A comparative analysis between instructional design methods
NASA Astrophysics Data System (ADS)
Mathew, Easow
The purpose of this research was to determine if there were differences in academic performance between students who participated in traditional versus collaborative problem-based learning (PBL) instructional design approaches to physics curricula. This study utilized a quantitative quasi-experimental design methodology to determine the significance of differences in pre- and posttest introductory physics exam performance between students who participated in traditional (i.e., control group) versus collaborative problem solving (PBL) instructional design (i.e., experimental group) approaches to physics curricula over a college semester in 2008. There were 42 student participants (N = 42) enrolled in an introductory physics course at the research site in the Spring 2008 semester who agreed to participate in this study after reading and signing informed consent documents. A total of 22 participants were assigned to the experimental group (n = 22) who participated in a PBL based teaching methodology along with traditional lecture methods. The other 20 students were assigned to the control group (n = 20) who participated in the traditional lecture teaching methodology. Both the courses were taught by experienced professors who have qualifications at the doctoral level. The results indicated statistically significant differences (p < .01) in academic performance between students who participated in traditional (i.e., lower physics posttest scores and lower differences between pre- and posttest scores) versus collaborative (i.e., higher physics posttest scores, and higher differences between pre- and posttest scores) instructional design approaches to physics curricula. Despite some slight differences in control group and experimental group demographic characteristics (gender, ethnicity, and age) there were statistically significant (p = .04) differences between female average academic improvement which was much higher than male average academic improvement (˜63%) in
Basic research on design analysis methods for rotorcraft vibrations
NASA Technical Reports Server (NTRS)
Hanagud, S.
1991-01-01
The objective of the present work was to develop a method for identifying physically plausible finite element system models of airframe structures from test data. The assumed models were based on linear elastic behavior with general (nonproportional) damping. Physical plausibility of the identified system matrices was insured by restricting the identification process to designated physical parameters only and not simply to the elements of the system matrices themselves. For example, in a large finite element model the identified parameters might be restricted to the moduli for each of the different materials used in the structure. In the case of damping, a restricted set of damping values might be assigned to finite elements based on the material type and on the fabrication processes used. In this case, different damping values might be associated with riveted, bolted and bonded elements. The method itself is developed first, and several approaches are outlined for computing the identified parameter values. The method is applied first to a simple structure for which the 'measured' response is actually synthesized from an assumed model. Both stiffness and damping parameter values are accurately identified. The true test, however, is the application to a full-scale airframe structure. In this case, a NASTRAN model and actual measured modal parameters formed the basis for the identification of a restricted set of physically plausible stiffness and damping parameters.
Designing arrays for modern high-resolution methods
Dowla, F.U.
1987-10-01
A bearing estimation study of seismic wavefields propagating from a strongly heterogeneous media shows that with the high-resolution MUSIC algorithm the bias of the direction estimate can be reduced by adopting a smaller aperture sub-array. Further, on this sub-array, the bias of the MUSIC algorithm is less than those of the MLM and Bartlett methods. On the full array, the performance for the three different methods are comparable. Improvement in bearing estimation in MUSIC with a reduced aperture might be attributed to increased signal coherency in the array. For methods with less resolution, the improved signal coherency in the smaller array is possible being offset by severe loss of resolution and the presence of weak secondary sources. Building upon the characteristics of real seismic wavefields, a design language has been developed to generate, modify, and test other arrays. Eigenstructures of wavefields and arrays have been studied empirically by simulation of a variety of realistic signals. 6 refs., 5 figs.
The finite element method for calculating the marine structural design
NASA Astrophysics Data System (ADS)
Ion, A.; Ticu, I.
2015-11-01
The aim of this paper is to optimally design and dimension marine structures in order for them to fulfil both functional and safety requirements. A master level of structural mechanics is vital in order to check tests and analysis and to develop new structures. This study can improve the calculation and estimation of the effects of hydrodynamics and of other loads; movements, strains and internal forces in fixed and floating platforms and ships. The finite element method (FEM) ensures basic understanding of the finite element model as applied on static cases including beam and plate elements, experience with static analysis of marine structures like platforms and ships, along with the basic understanding of dynamic response of systems with one degree of freedom and simple continuous beams, and also how analysis models can be established for real structures by the use of generalized coordinates and superposition.
POWER ANALYSIS FOR COMPLEX MEDIATIONAL DESIGNS USING MONTE CARLO METHODS
Thoemmes, Felix; MacKinnon, David P.; Reiser, Mark R.
2013-01-01
Applied researchers often include mediation effects in applications of advanced methods such as latent variable models and linear growth curve models. Guidance on how to estimate statistical power to detect mediation for these models has not yet been addressed in the literature. We describe a general framework for power analyses for complex mediational models. The approach is based on the well known technique of generating a large number of samples in a Monte Carlo study, and estimating power as the percentage of cases in which an estimate of interest is significantly different from zero. Examples of power calculation for commonly used mediational models are provided. Power analyses for the single mediator, multiple mediators, three-path mediation, mediation with latent variables, moderated mediation, and mediation in longitudinal designs are described. Annotated sample syntax for Mplus is appended and tabled values of required sample sizes are shown for some models. PMID:23935262
Unique Method for Generating Design Earthquake Time Histories
R. E. Spears
2008-07-01
A method has been developed which takes a seed earthquake time history and modifies it to produce given design response spectra. It is a multi-step process with an initial scaling step and then multiple refinement steps. It is unique in the fact that both the acceleration and displacement response spectra are considered when performing the fit (which primarily improves the low frequency acceleration response spectrum accuracy). Additionally, no matrix inversion is needed. The features include encouraging the code acceleration, velocity, and displacement ratios and attempting to fit the pseudo velocity response spectrum. Also, “smoothing” is done to transition the modified time history to the seed time history at its start and end. This is done in the time history regions below a cumulative energy of 5% and above a cumulative energy of 95%. Finally, the modified acceleration, velocity, and displacement time histories are adjusted to start and end with an amplitude of zero (using Fourier transform techniques for integration).
Development of impact design methods for ceramic gas turbine components
NASA Technical Reports Server (NTRS)
Song, J.; Cuccio, J.; Kington, H.
1990-01-01
Impact damage prediction methods are being developed to aid in the design of ceramic gas turbine engine components with improved impact resistance. Two impact damage modes were characterized: local, near the impact site, and structural, usually fast fracture away from the impact site. Local damage to Si3N4 impacted by Si3N4 spherical projectiles consists of ring and/or radial cracks around the impact point. In a mechanistic model being developed, impact damage is characterized as microcrack nucleation and propagation. The extent of damage is measured as volume fraction of microcracks. Model capability is demonstrated by simulating late impact tests. Structural failure is caused by tensile stress during impact exceeding material strength. The EPIC3 code was successfully used to predict blade structural failures in different size particle impacts on radial and axial blades.
Design method of water jet pump towards high cavitation performances
NASA Astrophysics Data System (ADS)
Cao, L. L.; Che, B. X.; Hu, L. J.; Wu, D. Z.
2016-05-01
As one of the crucial components for power supply, the propulsion system is of great significance to the advance speed, noise performances, stabilities and other associated critical performances of underwater vehicles. Developing towards much higher advance speed, the underwater vehicles make more critical demands on the performances of the propulsion system. Basically, the increased advance speed requires the significantly raised rotation speed of the propulsion system, which would result in the deteriorated cavitation performances and consequently limit the thrust and efficiency of the whole system. Compared with the traditional propeller, the water jet pump offers more favourite cavitation, propulsion efficiency and other associated performances. The present research focuses on the cavitation performances of the waterjet pump blade profile in expectation of enlarging its advantages in high-speed vehicle propulsion. Based on the specifications of a certain underwater vehicle, the design method of the waterjet blade with high cavitation performances was investigated in terms of numerical simulation.
Computational methods in metabolic engineering for strain design.
Long, Matthew R; Ong, Wai Kit; Reed, Jennifer L
2015-08-01
Metabolic engineering uses genetic approaches to control microbial metabolism to produce desired compounds. Computational tools can identify new biological routes to chemicals and the changes needed in host metabolism to improve chemical production. Recent computational efforts have focused on exploring what compounds can be made biologically using native, heterologous, and/or enzymes with broad specificity. Additionally, computational methods have been developed to suggest different types of genetic modifications (e.g. gene deletion/addition or up/down regulation), as well as suggest strategies meeting different criteria (e.g. high yield, high productivity, or substrate co-utilization). Strategies to improve the runtime performances have also been developed, which allow for more complex metabolic engineering strategies to be identified. Future incorporation of kinetic considerations will further improve strain design algorithms. PMID:25576846
Information processing systems, reasoning modules, and reasoning system design methods
Hohimer, Ryan E; Greitzer, Frank L; Hampton, Shawn D
2014-03-04
Information processing systems, reasoning modules, and reasoning system design methods are described. According to one aspect, an information processing system includes working memory comprising a semantic graph which comprises a plurality of abstractions, wherein the abstractions individually include an individual which is defined according to an ontology and a reasoning system comprising a plurality of reasoning modules which are configured to process different abstractions of the semantic graph, wherein a first of the reasoning modules is configured to process a plurality of abstractions which include individuals of a first classification type of the ontology and a second of the reasoning modules is configured to process a plurality of abstractions which include individuals of a second classification type of the ontology, wherein the first and second classification types are different.
Information processing systems, reasoning modules, and reasoning system design methods
Hohimer, Ryan E.; Greitzer, Frank L.; Hampton, Shawn D.
2015-08-18
Information processing systems, reasoning modules, and reasoning system design methods are described. According to one aspect, an information processing system includes working memory comprising a semantic graph which comprises a plurality of abstractions, wherein the abstractions individually include an individual which is defined according to an ontology and a reasoning system comprising a plurality of reasoning modules which are configured to process different abstractions of the semantic graph, wherein a first of the reasoning modules is configured to process a plurality of abstractions which include individuals of a first classification type of the ontology and a second of the reasoning modules is configured to process a plurality of abstractions which include individuals of a second classification type of the ontology, wherein the first and second classification types are different.
Information processing systems, reasoning modules, and reasoning system design methods
Hohimer, Ryan E.; Greitzer, Frank L.; Hampton, Shawn D.
2016-08-23
Information processing systems, reasoning modules, and reasoning system design methods are described. According to one aspect, an information processing system includes working memory comprising a semantic graph which comprises a plurality of abstractions, wherein the abstractions individually include an individual which is defined according to an ontology and a reasoning system comprising a plurality of reasoning modules which are configured to process different abstractions of the semantic graph, wherein a first of the reasoning modules is configured to process a plurality of abstractions which include individuals of a first classification type of the ontology and a second of the reasoning modules is configured to process a plurality of abstractions which include individuals of a second classification type of the ontology, wherein the first and second classification types are different.
Virtual Design Method for Controlled Failure in Foldcore Sandwich Panels
NASA Astrophysics Data System (ADS)
Sturm, Ralf; Fischer, S.
2015-12-01
For certification, novel fuselage concepts have to prove equivalent crashworthiness standards compared to the existing metal reference design. Due to the brittle failure behaviour of CFRP this requirement can only be fulfilled by a controlled progressive crash kinematics. Experiments showed that the failure of a twin-walled fuselage panel can be controlled by a local modification of the core through-thickness compression strength. For folded cores the required change in core properties can be integrated by a modification of the fold pattern. However, the complexity of folded cores requires a virtual design methodology for tailoring the fold pattern according to all static and crash relevant requirements. In this context a foldcore micromodel simulation method is presented to identify the structural response of a twin-walled fuselage panels with folded core under crash relevant loading condition. The simulations showed that a high degree of correlation is required before simulation can replace expensive testing. In the presented studies, the necessary correlation quality could only be obtained by including imperfections of the core material in the micromodel simulation approach.
ERIC Educational Resources Information Center
Rowley, Kurt
2005-01-01
A multi-stage study of the practices of expert courseware designers was conducted with the final goal of identifying methods for assisting non-experts with the design of effective instructional systems. A total of 25 expert designers were involved in all stages of the inquiry. A model of the expert courseware design process was created, tested,…
TIR collimator designs based on point source and extended source methods
NASA Astrophysics Data System (ADS)
Talpur, T.; Herkommer, A.
2015-09-01
TIR collimator are essential illumination components demanding high efficiency, accuracy, and uniformity. Various illumination design methods have been developed for different design domains, including tailoring method, design via optimization, mapping and feedback method, and the simultaneous multiple surface (SMS) method. This paper summarizes and compares the performance of these methods along with the advantages and the limitations.
Optical Design Methods: Your Head As A Personal Computer
NASA Astrophysics Data System (ADS)
Shafer, David
1985-07-01
Several design approaches are described which feature the use of your head as a design tool. This involves thinking about the design task at hand, trying to break it into separate, easily understood subtasks, and approaching these in a creative and intelligent fashion, as only humans can do. You and your computer can become a very powerful team when this design philosophy is adopted.
Integrated Risk Information System (IRIS), (Volume 4, Issue 3) (for microcomputers). Data file
Not Available
1991-07-01
The Integrated Risk Information System (IRIS) provides information on how chemicals affect human health and is a primary source of Environmental Protection Agency (EPA) risk assessment information on chemicals of environmental concern. It serves as a guide for the hazard identification and dose-response assessment steps of EPA risk assessments. IRIS makes chemical-specific risk information readily available to those who must perform risk assessments and also increases consistency in risk management decisions. The principal section of IRIS is the chemical files. The chemical files contain: oral reference doses (RfD) and inhalation reference concentrations (RfC) for noncarcinogens; oral and inhalation carcinogen assessments; summarized Drinking Water Health Advisories; summaries of selected EPA regulations; supplementary data; and full bibliographic citations. The primary types of health assessment information in IRIS are oral RfDs, inhalation RfCs and carcinogen assessments. There are currently over 450 chemicals in IRIS.
Why consumers behave as they do with respect to food safety and risk information.
Verbeke, Wim; Frewer, Lynn J; Scholderer, Joachim; De Brabander, Hubert F
2007-03-14
In recent years, it seems that consumers are generally uncertain about the safety and quality of their food and their risk perception differs substantially from that of experts. Hormone and veterinary drug residues in meat persist to occupy a high position in European consumers' food concern rankings. The aim of this contribution is to provide a better understanding to food risk analysts of why consumers behave as they do with respect to food safety and risk information. This paper presents some cases of seemingly irrational and inconsistent consumer behaviour with respect to food safety and risk information and provides explanations for these behaviours based on the nature of the risk and individual psychological processes. Potential solutions for rebuilding consumer confidence in food safety and bridging between lay and expert opinions towards food risks are reviewed. These include traceability and labelling, segmented communication approaches and public involvement in risk management decision-making. PMID:17386689
Treatment of uncertainties associated with PRAs in risk-informed decision making (NUREG1855).
Wheeler, Timothy A.
2010-06-01
This document provides guidance on how to treat uncertainties associated with probabilistic risk assessment (PRA) in risk-informed decisionmaking. The objectives of this guidance include fostering an understanding of the uncertainties associated with PRA and their impact on the results of PRA and providing a pragmatic approach to addressing these uncertainties in the context of the decisionmaking. In implementing risk-informed decisionmaking, the U.S. Nuclear Regulatory Commission expects that appropriate consideration of uncertainty will be given in the analyses used to support the decision and in the interpretation of the findings of those analyses. To meet the objective of this document, it is necessary to understand the role that PRA results play in the context of the decision process. To define this context, this document provides an overview of the risk-informed decisionmaking process itself. With the context defined, this document describes the characteristics of a risk model and, in particular, a PRA. This description includes recognition that a PRA, being a probabilistic model, characterizes aleatory uncertainty that results from randomness associated with the events of the model. Because the focus of this document is epistemic uncertainty (i.e., uncertainties in the formulation of the PRA model), it provides guidance on identifying and describing the different types of sources of epistemic uncertainty and the different ways that they are treated. The different types of epistemic uncertainty are parameter, model, and completeness uncertainties. The final part of the guidance addresses the uncertainty in PRA results in the context of riskinformed decisionmaking and, in particular, the interpretation of the results of the uncertainty analysis when comparing PRA results with the acceptance criteria established for a specified application. In addition, guidance is provided for addressing completeness uncertainty in risk-informed decision making. Such
Progress toward regulatory acceptance of risk-informed inspection programs for nuclear power plants
NASA Astrophysics Data System (ADS)
Hedden, Owen F.; Cowfer, C. David
1996-11-01
This paper will describe work within the American Society of Mechanical Engineers committee responsible for rules for inservice inspection of nuclear power plants. Work is progressing with the objective of producing proposals for risk-informed inspection programs that will be incorporated by the US Nuclear Regulatory Commission into the Federal Regulations Governing the construction and inservice inspection of al domestic commercial power plants. The paper will describe in detail the two primary proposals now under development and review. Both are directed toward enhancing safety while reducing the expense of periodic examination of piping welds. The first proposal provides a sound technical basis for reducing the number of Class 1 piping weld examinations as much as 60 percent while improving or maintaining equivalent safety. This is accomplished by using risk-informed techniques to re-establish the most important areas to examine. The second is a broader approach addressing all piping systems considered to be important under risk-informed assessment techniques. Both proposals are based on recent insights into risk analysis techniques developed within the pressure vessel industry, and both require evaluation of theoretical analysis and inputs of practical experience related to a wide variety of detrimental conditions. These proposals are being supported by pilot programs in a number of operating nuclear power plants. The authors will also attempt to explain the institutional constraints inherent in the process of obtaining regulatory recognition of proposals developed cooperatively by industry and the regulatory agency.
Design optimization methods for genomic DNA tiling arrays
Bertone, Paul; Trifonov, Valery; Rozowsky, Joel S.; Schubert, Falk; Emanuelsson, Olof; Karro, John; Kao, Ming-Yang; Snyder, Michael; Gerstein, Mark
2006-01-01
A recent development in microarray research entails the unbiased coverage, or tiling, of genomic DNA for the large-scale identification of transcribed sequences and regulatory elements. A central issue in designing tiling arrays is that of arriving at a single-copy tile path, as significant sequence cross-hybridization can result from the presence of non-unique probes on the array. Due to the fragmentation of genomic DNA caused by the widespread distribution of repetitive elements, the problem of obtaining adequate sequence coverage increases with the sizes of subsequence tiles that are to be included in the design. This becomes increasingly problematic when considering complex eukaryotic genomes that contain many thousands of interspersed repeats. The general problem of sequence tiling can be framed as finding an optimal partitioning of non-repetitive subsequences over a prescribed range of tile sizes, on a DNA sequence comprising repetitive and non-repetitive regions. Exact solutions to the tiling problem become computationally infeasible when applied to large genomes, but successive optimizations are developed that allow their practical implementation. These include an efficient method for determining the degree of similarity of many oligonucleotide sequences over large genomes, and two algorithms for finding an optimal tile path composed of longer sequence tiles. The first algorithm, a dynamic programming approach, finds an optimal tiling in linear time and space; the second applies a heuristic search to reduce the space complexity to a constant requirement. A Web resource has also been developed, accessible at http://tiling.gersteinlab.org, to generate optimal tile paths from user-provided DNA sequences. PMID:16365382
Shimada, Masato; Suzuki, Wataru; Yamada, Shuho; Inoue, Masato
2016-01-01
To achieve a Universal Design, designers must consider diverse users' physical and functional requirements for their products. However, satisfying these requirements and obtaining the information which is necessary for designing a universal product is very difficult. Therefore, we propose a new design method based on the concept of set-based design to solve these issues. This paper discusses the suitability of proposed design method by applying bicycle frame design problem. PMID:27534334
Visual Narrative Research Methods as Performance in Industrial Design Education
ERIC Educational Resources Information Center
Campbell, Laurel H.; McDonagh, Deana
2009-01-01
This article discusses teaching empathic research methodology as performance. The authors describe their collaboration in an activity to help undergraduate industrial design students learn empathy for others when designing products for use by diverse or underrepresented people. The authors propose that an industrial design curriculum would benefit…
An entropy method for floodplain monitoring network design
NASA Astrophysics Data System (ADS)
Ridolfi, E.; Yan, K.; Alfonso, L.; Di Baldassarre, G.; Napolitano, F.; Russo, F.; Bates, Paul D.
2012-09-01
In recent years an increasing number of flood-related fatalities has highlighted the necessity of improving flood risk management to reduce human and economic losses. In this framework, monitoring of flood-prone areas is a key factor for building a resilient environment. In this paper a method for designing a floodplain monitoring network is presented. A redundant network of cheap wireless sensors (GridStix) measuring water depth is considered over a reach of the River Dee (UK), with sensors placed both in the channel and in the floodplain. Through a Three Objective Optimization Problem (TOOP) the best layouts of sensors are evaluated, minimizing their redundancy, maximizing their joint information content and maximizing the accuracy of the observations. A simple raster-based inundation model (LISFLOOD-FP) is used to generate a synthetic GridStix data set of water stages. The Digital Elevation Model (DEM) that is used for hydraulic model building is the globally and freely available SRTM DEM.
The Chinese American Eye Study: Design and Methods
Varma, Rohit; Hsu, Chunyi; Wang, Dandan; Torres, Mina; Azen, Stanley P.
2016-01-01
Purpose To summarize the study design, operational strategies and procedures of the Chinese American Eye Study (CHES), a population-based assessment of the prevalence of visual impairment, ocular disease, and visual functioning in Chinese Americans. Methods This population-based, cross-sectional study, included 4,570 Chinese, 50 years and older, residing in the city of Monterey Park, California. Each eligible participant completed a detailed interview and eye examination. The interview included an assessment of demographic, behavioral, and ocular risk factors and health-related and vision-related quality of life. The eye examination included measurements of visual acuity, intraocular pressure, visual fields, fundus and optic disc photography, a detailed anterior and posterior segment examination, and measurements of blood pressure, glycosylated hemoglobin levels, and blood glucose levels. Results The objectives of the CHES are to obtain prevalence estimates of visual impairment, refractive error, diabetic retinopathy, open-angle and angle-closure glaucoma, lens opacities, and age-related macular degeneration in Chinese-Americans. In addition, outcomes include effect estimates for risk factors associated with eye diseases. Lastly, CHES will investigate the genetic determinates of myopia and glaucoma. Conclusion The CHES will provide information about the prevalence and risk factors of ocular diseases in one of the fastest growing minority groups in the United States. PMID:24044409
Design and methods of the national Vietnam veterans longitudinal study.
Schlenger, William E; Corry, Nida H; Kulka, Richard A; Williams, Christianna S; Henn-Haase, Clare; Marmar, Charles R
2015-09-01
The National Vietnam Veterans Longitudinal Study (NVVLS) is the second assessment of a representative cohort of US veterans who served during the Vietnam War era, either in Vietnam or elsewhere. The cohort was initially surveyed in the National Vietnam Veterans Readjustment Study (NVVRS) from 1984 to 1988 to assess the prevalence, incidence, and effects of post-traumatic stress disorder (PTSD) and other post-war problems. The NVVLS sought to re-interview the cohort to assess the long-term course of PTSD. NVVLS data collection began July 3, 2012 and ended May 17, 2013, comprising three components: a mailed health questionnaire, a telephone health survey interview, and, for a probability sample of theater Veterans, a clinical diagnostic telephone interview administered by licensed psychologists. Excluding decedents, 78.8% completed the questionnaire and/or telephone survey, and 55.0% of selected living veterans participated in the clinical interview. This report provides a description of the NVVLS design and methods. Together, the NVVRS and NVVLS constitute a nationally representative longitudinal study of Vietnam veterans, and extend the NVVRS as a critical resource for scientific and policy analyses for Vietnam veterans, with policy relevance for Iraq and Afghanistan veterans. PMID:26096554
A decision-based perspective for the design of methods for systems design
NASA Technical Reports Server (NTRS)
Mistree, Farrokh; Muster, Douglas; Shupe, Jon A.; Allen, Janet K.
1989-01-01
Organization of material, a definition of decision based design, a hierarchy of decision based design, the decision support problem technique, a conceptual model design that can be manufactured and maintained, meta-design, computer-based design, action learning, and the characteristics of decisions are among the topics covered.
NASA Technical Reports Server (NTRS)
Sobieszczanski-Sobieski, Jaroslaw
1998-01-01
The paper identifies speed, agility, human interface, generation of sensitivity information, task decomposition, and data transmission (including storage) as important attributes for a computer environment to have in order to support engineering design effectively. It is argued that when examined in terms of these attributes the presently available environment can be shown to be inadequate a radical improvement is needed, and it may be achieved by combining new methods that have recently emerged from multidisciplinary design optimization (MDO) with massively parallel processing computer technology. The caveat is that, for successful use of that technology in engineering computing, new paradigms for computing will have to be developed - specifically, innovative algorithms that are intrinsically parallel so that their performance scales up linearly with the number of processors. It may be speculated that the idea of simulating a complex behavior by interaction of a large number of very simple models may be an inspiration for the above algorithms, the cellular automata are an example. Because of the long lead time needed to develop and mature new paradigms, development should be now, even though the widespread availability of massively parallel processing is still a few years away.
NASA Technical Reports Server (NTRS)
Sobieszczanski-Sobieski, Jaroslaw
1999-01-01
The paper identifies speed, agility, human interface, generation of sensitivity information, task decomposition, and data transmission (including storage) as important attributes for a computer environment to have in order to support engineering design effectively. It is argued that when examined in terms of these attributes the presently available environment can be shown to be inadequate. A radical improvement is needed, and it may be achieved by combining new methods that have recently emerged from multidisciplinary design optimisation (MDO) with massively parallel processing computer technology. The caveat is that, for successful use of that technology in engineering computing, new paradigms for computing will have to be developed - specifically, innovative algorithms that are intrinsically parallel so that their performance scales up linearly with the number of processors. It may be speculated that the idea of simulating a complex behaviour by interaction of a large number of very simple models may be an inspiration for the above algorithms; the cellular automata are an example. Because of the long lead time needed to develop and mature new paradigms, development should begin now, even though the widespread availability of massively parallel processing is still a few years away.
Active cooling design for scramjet engines using optimization methods
NASA Technical Reports Server (NTRS)
Scotti, Stephen J.; Martin, Carl J.; Lucas, Stephen H.
1988-01-01
A methodology for using optimization in designing metallic cooling jackets for scramjet engines is presented. The optimal design minimizes the required coolant flow rate subject to temperature, mechanical-stress, and thermal-fatigue-life constraints on the cooling-jacket panels, and Mach-number and pressure constraints on the coolant exiting the panel. The analytical basis for the methodology is presented, and results for the optimal design of panels are shown to demonstrate its utility.
Active cooling design for scramjet engines using optimization methods
NASA Technical Reports Server (NTRS)
Scotti, Stephen J.; Martin, Carl J.; Lucas, Stephen H.
1988-01-01
A methodology for using optimization in designing metallic cooling jackets for scramjet engines is presented. The optimal design minimizes the required coolant flow rate subject to temperature, mechanical-stress, and thermal-fatigue-life constraints on the cooling-jacket panels, and Mach-number and pressure contraints on the coolant exiting the panel. The analytical basis for the methodology is presented, and results for the optimal design of panels are shown to demonstrate its utility.
Investigating a Method of Scaffolding Student-Designed Experiments
NASA Astrophysics Data System (ADS)
Morgan, Kelly; Brooks, David W.
2012-08-01
The process of designing an experiment is a difficult one. Students often struggle to perform such tasks as the design process places a large cognitive load on students. Scaffolding is the process of providing support for a student to allow them to complete tasks they would otherwise not have been able to complete. This study sought to investigate backwards-design, one form of scaffolding the experimental design process for students. Students were guided through the design process in a backwards manner (designing the results section first and working backwards through typical report components to the materials and safety sections). The use of reflective prompts as possible scaffold for metacognitive processes was also studied. Scaffolding was in the form of a computer application built specifically for this purpose. Four versions of the computer application were randomly assigned to 102 high school chemistry students and students were asked to the design of an experiment, producing a report. The use of backwards-design scaffolding resulted in significantly higher performance on lab reports. The addition of reflective prompts reduced the effect of backwards-design scaffolding in lower-level students.
Development of Combinatorial Methods for Alloy Design and Optimization
Pharr, George M.; George, Easo P.; Santella, Michael L
2005-07-01
The primary goal of this research was to develop a comprehensive methodology for designing and optimizing metallic alloys by combinatorial principles. Because conventional techniques for alloy preparation are unavoidably restrictive in the range of alloy composition that can be examined, combinatorial methods promise to significantly reduce the time, energy, and expense needed for alloy design. Combinatorial methods can be developed not only to optimize existing alloys, but to explore and develop new ones as well. The scientific approach involved fabricating an alloy specimen with a continuous distribution of binary and ternary alloy compositions across its surface--an ''alloy library''--and then using spatially resolved probing techniques to characterize its structure, composition, and relevant properties. The three specific objectives of the project were: (1) to devise means by which simple test specimens with a library of alloy compositions spanning the range interest can be produced; (2) to assess how well the properties of the combinatorial specimen reproduce those of the conventionally processed alloys; and (3) to devise screening tools which can be used to rapidly assess the important properties of the alloys. As proof of principle, the methodology was applied to the Fe-Ni-Cr ternary alloy system that constitutes many commercially important materials such as stainless steels and the H-series and C-series heat and corrosion resistant casting alloys. Three different techniques were developed for making alloy libraries: (1) vapor deposition of discrete thin films on an appropriate substrate and then alloying them together by solid-state diffusion; (2) co-deposition of the alloying elements from three separate magnetron sputtering sources onto an inert substrate; and (3) localized melting of thin films with a focused electron-beam welding system. Each of the techniques was found to have its own advantages and disadvantages. A new and very powerful technique for
Applications of numerical optimization methods to helicopter design problems: A survey
NASA Technical Reports Server (NTRS)
Miura, H.
1984-01-01
A survey of applications of mathematical programming methods is used to improve the design of helicopters and their components. Applications of multivariable search techniques in the finite dimensional space are considered. Five categories of helicopter design problems are considered: (1) conceptual and preliminary design, (2) rotor-system design, (3) airframe structures design, (4) control system design, and (5) flight trajectory planning. Key technical progress in numerical optimization methods relevant to rotorcraft applications are summarized.
Applications of numerical optimization methods to helicopter design problems - A survey
NASA Technical Reports Server (NTRS)
Miura, H.
1985-01-01
A survey of applications of mathematical programming methods is used to improve the design of helicopters and their components. Applications of multivariable search techniques in the finite dimensional space are considered. Five categories of helicopter design problems are considered: (1) conceptual and preliminary design, (2) rotor-system design, (3) airframe structures design, (4) control system design, and (5) flight trajectory planning. Key technical progress in numerical optimization methods relevant to rotorcraft applications are summarized.
Applications of numerical optimization methods to helicopter design problems - A survey
NASA Technical Reports Server (NTRS)
Miura, H.
1984-01-01
A survey of applications of mathematical programming methods is used to improve the design of helicopters and their components. Applications of multivariable search techniques in the finite dimensional space are considered. Five categories of helicopter design problems are considered: (1) conceptual and preliminary design, (2) rotor-system design, (3) airframe structures design, (4) control system design, and (5) flight trajectory planning. Key technical progress in numerical optimization methods relevant to rotorcraft applications are summarized.
NASA Technical Reports Server (NTRS)
Merchant, D. H.
1976-01-01
Methods are presented for calculating design limit loads compatible with probabilistic structural design criteria. The approach is based on the concept that the desired limit load, defined as the largest load occurring in a mission, is a random variable having a specific probability distribution which may be determined from extreme-value theory. The design limit load, defined as a particular of this random limit load, is the value conventionally used in structural design. Methods are presented for determining the limit load probability distributions from both time-domain and frequency-domain dynamic load simulations. Numerical demonstrations of the method are also presented.
Investigating a Method of Scaffolding Student-Designed Experiments
ERIC Educational Resources Information Center
Morgan, Kelly; Brooks, David W.
2012-01-01
The process of designing an experiment is a difficult one. Students often struggle to perform such tasks as the design process places a large cognitive load on students. Scaffolding is the process of providing support for a student to allow them to complete tasks they would otherwise not have been able to complete. This study sought to investigate…
Teaching Improvement Model Designed with DEA Method and Management Matrix
ERIC Educational Resources Information Center
Montoneri, Bernard
2014-01-01
This study uses student evaluation of teachers to design a teaching improvement matrix based on teaching efficiency and performance by combining management matrix and data envelopment analysis. This matrix is designed to formulate suggestions to improve teaching. The research sample consists of 42 classes of freshmen following a course of English…
Developing Baby Bag Design by Using Kansei Engineering Method
NASA Astrophysics Data System (ADS)
Janari, D.; Rakhmawati, A.
2016-01-01
Consumer's preferences and market demand are essential factors for product's success. Thus, in achieving its success, a product should have design that could fulfill consumer's expectation. Purpose of this research is accomplishing baby bag product as stipulated by Kansei. The results that represent Kanseiwords are; neat, unique, comfortable, safe, modern, gentle, elegant, antique, attractive, simple, spacious, creative, colorful, durable, stylish, smooth and strong. Identification value on significance of correlation for durable attribute is 0,000 < 0,005, which means significant to baby's bag. While the value of coefficient regression is 0,812 < 0,005, which means that durable attribute insignificant to baby's bag.The result of the baby's bag final design selectionbased on the questionnaire 3 is resulting the combination of all design. Space for clothes, diaper's space, shoulder grip, side grip, bottle's heater pocket and bottle's pocket are derived from design 1. Top grip, space for clothes, shoulder grip, and side grip are derived from design 2.Others design that were taken are, spaces for clothes from design 3, diaper's space and clothes’ space from design 4.
METHODS FOR INTEGRATING ENVIRONMENTAL CONSIDERATIONS INTO CHEMICAL PROCESS DESIGN DECISIONS
The objective of this cooperative agreement was to postulate a means by which an engineer could routinely include environmental considerations in day-to-day conceptual design problems; a means that could easily integrate with existing design processes, and thus avoid massive retr...
Parametric design of a Francis turbine runner by means of a three-dimensional inverse design method
NASA Astrophysics Data System (ADS)
Daneshkah, K.; Zangeneh, M.
2010-08-01
The present paper describes the parametric design of a Francis turbine runner. The runner geometry is parameterized by means of a 3D inverse design method, while CFD analyses were performed to assess the hydrodymanic and suction performance of different design configurations that were investigated. An initial runner design was first generated and used as baseline for parametric study. The effects of several design parameter, namely stacking condition and blade loading was then investigated in order to determine their effect on the suction performance. The use of blade parameterization using the inverse method lead to a major advantage for design of Francis turbine runners, as the three-dimensional blade shape is describe by parameters that closely related to the flow field namely blade loading and stacking condition that have a direct impact on the hydrodynamics of the flow field. On the basis of this study, an optimum configuration was designed which results in a cavitation free flow in the runner, while maintaining a high level of hydraulic efficiency. The paper highlights design guidelines for application of inverse design method to Francis turbine runners. The design guidelines have a general validity and can be used for similar design applications since they are based on flow field analyses and on hydrodynamic design parameters.
Consumers' preferences for the communication of risk information in drug advertising.
Davis, Joel J
2007-01-01
Research was conducted to identify consumers' preferences regarding the form, content, and placement of drug side-effect information in direct-to-consumer (DTC) advertising. Specific questions explored preferences for the presence or absence of numeric information, the use of placebo and discontinuation groups as a context for understanding drug risk, the sequence in which side effects are presented, and the placement of side-effect statements on DTC Web sites. Consumers prefer detailed, readily accessible risk information--preferences that are a major departure from current advertiser practices and from what current and proposed Food and Drug Administration (FDA) regulations require. PMID:17485767
Categorisation of visualisation methods to support the design of Human-Computer Interaction Systems.
Li, Katie; Tiwari, Ashutosh; Alcock, Jeffrey; Bermell-Garcia, Pablo
2016-07-01
During the design of Human-Computer Interaction (HCI) systems, the creation of visual artefacts forms an important part of design. On one hand producing a visual artefact has a number of advantages: it helps designers to externalise their thought and acts as a common language between different stakeholders. On the other hand, if an inappropriate visualisation method is employed it could hinder the design process. To support the design of HCI systems, this paper reviews the categorisation of visualisation methods used in HCI. A keyword search is conducted to identify a) current HCI design methods, b) approaches of selecting these methods. The resulting design methods are filtered to create a list of just visualisation methods. These are then categorised using the approaches identified in (b). As a result 23 HCI visualisation methods are identified and categorised in 5 selection approaches (The Recipient, Primary Purpose, Visual Archetype, Interaction Type, and The Design Process). PMID:26995039
NASA Astrophysics Data System (ADS)
Adrich, Przemysław
2016-05-01
In Part I of this work existing methods and problems in dual foil electron beam forming system design are presented. On this basis, a new method of designing these systems is introduced. The motivation behind this work is to eliminate the shortcomings of the existing design methods and improve overall efficiency of the dual foil design process. The existing methods are based on approximate analytical models applied in an unrealistically simplified geometry. Designing a dual foil system with these methods is a rather labor intensive task as corrections to account for the effects not included in the analytical models have to be calculated separately and accounted for in an iterative procedure. To eliminate these drawbacks, the new design method is based entirely on Monte Carlo modeling in a realistic geometry and using physics models that include all relevant processes. In our approach, an optimal configuration of the dual foil system is found by means of a systematic, automatized scan of the system performance in function of parameters of the foils. The new method, while being computationally intensive, minimizes the involvement of the designer and considerably shortens the overall design time. The results are of high quality as all the relevant physics and geometry details are naturally accounted for. To demonstrate the feasibility of practical implementation of the new method, specialized software tools were developed and applied to solve a real life design problem, as described in Part II of this work.
Airfoil design and optimization methods: recent progress at NLR
NASA Astrophysics Data System (ADS)
Soemarwoto, B. I.; Labrujère, Th. E.
1999-05-01
The present paper considers the problem of aerodynamic airfoil shape optimization where the shape of an airfoil is to be determined such that a priori specified design criteria will be met to the best possible extent. The design criteria are formulated by defining an objective or cost function, the minimum of which represents the solution to the design problem. A survey is given of developments at NLR applying the adjoint operator approach, utilizing a compressible inviscid flow model based on the Euler equations and a compressible viscous flow model based on the Reynolds-averaged Navier-Stokes equations. Computational results are presented for a two-point drag-reduction design problem. Copyright
Third order TRANSPORT with MAD (Methodical Accelerator Design) input
Carey, D.C.
1988-09-20
This paper describes computer-aided design codes for particle accelerators. Among the topics discussed are: input beam description; parameters and algebraic expressions; the physical elements; beam lines; operations; and third-order transfer matrix. (LSP)
Development of panel methods for subsonic analysis and design
NASA Technical Reports Server (NTRS)
Bristow, D. R.
1980-01-01
Two computer programs, developed for subsonic inviscid analysis and design are described. The first solves arbitrary mixed analysis design problems for multielement airfoils in two dimensional flow. The second calculates the pressure distribution for arbitrary lifting or nonlifting three dimensional configurations. In each program, inviscid flow is modelled by using distributed source doublet singularities on configuration surface panels. Numerical formulations and representative solutions are presented for the programs.
Practical design methods for barrier pillars. Information circular/1995
Koehler, J.R.; Tadolini, S.C.
1995-11-01
Effective barrier pillar design is essential for safe and productive underground coal mining. This U.S. Bureau of Mines report presents an overview of available barrier pillar design methodologies that incorporate sound engineering principles while remaining practical for everyday usage. Nomographs and examples are presented to assist in the determination of proper barrier pillar sizing. Additionally, performance evaluation techniques and criteria are included to assist in determining the effectiveness of selected barrier pillar configurations.
The cryogenic balance design and balance calibration methods
NASA Astrophysics Data System (ADS)
Ewald, B.; Polanski, L.; Graewe, E.
1992-07-01
The current status of a program aimed at the development of a cryogenic balance for the European Transonic Wind Tunnel is reviewed. In particular, attention is given to the cryogenic balance design philosophy, mechanical balance design, reliability and accuracy, cryogenic balance calibration concept, and the concept of an automatic calibration machine. It is shown that the use of the automatic calibration machine will improve the accuracy of calibration while reducing the man power and time required for balance calibration.
Aircraft design for mission performance using nonlinear multiobjective optimization methods
NASA Technical Reports Server (NTRS)
Dovi, Augustine R.; Wrenn, Gregory A.
1990-01-01
A new technique which converts a constrained optimization problem to an unconstrained one where conflicting figures of merit may be simultaneously considered was combined with a complex mission analysis system. The method is compared with existing single and multiobjective optimization methods. A primary benefit from this new method for multiobjective optimization is the elimination of separate optimizations for each objective, which is required by some optimization methods. A typical wide body transport aircraft is used for the comparative studies.
A Preliminary Rubric Design to Evaluate Mixed Methods Research
ERIC Educational Resources Information Center
Burrows, Timothy J.
2013-01-01
With the increase in frequency of the use of mixed methods, both in research publications and in externally funded grants there are increasing calls for a set of standards to assess the quality of mixed methods research. The purpose of this mixed methods study was to conduct a multi-phase analysis to create a preliminary rubric to evaluate mixed…
Multiple methods integration for structural mechanics analysis and design
NASA Technical Reports Server (NTRS)
Housner, J. M.; Aminpour, M. A.
1991-01-01
A new research area of multiple methods integration is proposed for joining diverse methods of structural mechanics analysis which interact with one another. Three categories of multiple methods are defined: those in which a physical interface are well defined; those in which a physical interface is not well-defined, but selected; and those in which the interface is a mathematical transformation. Two fundamental integration procedures are presented that can be extended to integrate various methods (e.g., finite elements, Rayleigh Ritz, Galerkin, and integral methods) with one another. Since the finite element method will likely be the major method to be integrated, its enhanced robustness under element distortion is also examined and a new robust shell element is demonstrated.
NASA Astrophysics Data System (ADS)
Vimal, S.; Tarboton, D. G.; Band, L. E.; Duncan, J. M.; Lovette, J. P.; Corzo, G.; Miles, B.
2015-12-01
Prioritizing river restoration requires information on river geometry. In many states in the US detailed river geometry has been collected for floodplain mapping and is available in Flood Risk Information Systems (FRIS). In particular, North Carolina has, for its 100 Counties, developed a database of numerous HEC-RAS models which are available through its Flood Risk Information System (FRIS). These models that include over 260 variables were developed and updated by numerous contractors. They contain detailed surveyed or LiDAR derived cross-sections and modeled flood extents for different extreme event return periods. In this work, over 4700 HEC-RAS models' data was integrated and upscaled to utilize detailed cross-section information and 100-year modelled flood extent information to enable river restoration prioritization for the entire state of North Carolina. We developed procedures to extract geomorphic properties such as entrenchment ratio, incision ratio, etc. from these models. Entrenchment ratio quantifies the vertical containment of rivers and thereby their vulnerability to flooding and incision ratio quantifies the depth per unit width. A map of entrenchment ratio for the whole state was derived by linking these model results to a geodatabase. A ranking of highly entrenched counties enabling prioritization for flood allowance and mitigation was obtained. The results were shared through HydroShare and web maps developed for their visualization using Google Maps Engine API.
Statistical Methods for Rapid Aerothermal Analysis and Design Technology
NASA Technical Reports Server (NTRS)
Morgan, Carolyn; DePriest, Douglas; Thompson, Richard (Technical Monitor)
2002-01-01
The cost and safety goals for NASA's next generation of reusable launch vehicle (RLV) will require that rapid high-fidelity aerothermodynamic design tools be used early in the design cycle. To meet these requirements, it is desirable to establish statistical models that quantify and improve the accuracy, extend the applicability, and enable combined analyses using existing prediction tools. The research work was focused on establishing the suitable mathematical/statistical models for these purposes. It is anticipated that the resulting models can be incorporated into a software tool to provide rapid, variable-fidelity, aerothermal environments to predict heating along an arbitrary trajectory. This work will support development of an integrated design tool to perform automated thermal protection system (TPS) sizing and material selection.
A method for designing robust multivariable feedback systems
NASA Technical Reports Server (NTRS)
Milich, David Albert; Athans, Michael; Valavani, Lena; Stein, Gunter
1988-01-01
A new methodology is developed for the synthesis of linear, time-invariant (LTI) controllers for multivariable LTI systems. The aim is to achieve stability and performance robustness of the feedback system in the presence of multiple unstructured uncertainty blocks; i.e., to satisfy a frequency-domain inequality in terms of the structured singular value. The design technique is referred to as the Causality Recovery Methodology (CRM). Starting with an initial (nominally) stabilizing compensator, the CRM produces a closed-loop system whose performance-robustness is at least as good as, and hopefully superior to, that of the original design. The robustness improvement is obtained by solving an infinite-dimensional, convex optimization program. A finite-dimensional implementation of the CRM was developed, and it was applied to a multivariate design example.
A method for designing robust multivariable feedback systems
NASA Technical Reports Server (NTRS)
Milich, David A.; Athans, Michael; Valavani, Lena; Stein, Gunter
1988-01-01
A new methodology is developed for the synthesis of linear, time-invariant (LTI) controllers for multivariable LTI systems. The aim is to achieve stability and performance robustness of the feedback system in the presence of multiple unstructured uncertainty blocks; i.e., to satisfy a frequency-domain inequality in terms of the structured singular value. The design technique is referred to as the causality recovery methodology (CRM). Starting with an initial (nominally) stabilizing compensator, the CRM produces a closed-loop system whose performance-robustness is at least as good as, and hopefully superior to, that of the original design. The robustness improvement is obtained by solving an infinite-dimensional, convex optimization program. A finite-dimensional implementation of the CRM was developed, and it was applied to a multivariate design example.
Prevalence of Mixed-Methods Sampling Designs in Social Science Research
ERIC Educational Resources Information Center
Collins, Kathleen M. T.
2006-01-01
The purpose of this mixed-methods study was to document the prevalence of sampling designs utilised in mixed-methods research and to examine the interpretive consistency between interpretations made in mixed-methods studies and the sampling design used. Classification of studies was based on a two-dimensional mixed-methods sampling model. This…
Advanced 3D inverse method for designing turbomachine blades
Dang, T.
1995-10-01
To meet the goal of 60% plant-cycle efficiency or better set in the ATS Program for baseload utility scale power generation, several critical technologies need to be developed. One such need is the improvement of component efficiencies. This work addresses the issue of improving the performance of turbo-machine components in gas turbines through the development of an advanced three-dimensional and viscous blade design system. This technology is needed to replace some elements in current design systems that are based on outdated technology.
Advanced 3D inverse method for designing turbomachine blades
Dang, T.
1995-12-31
To meet the goal of 60% plant-cycle efficiency or better set in the ATS Program for baseload utility scale power generation, several critical technologies need to be developed. One such need is the improvement of component efficiencies. This work addresses the issue of improving the performance of turbo-machine components in gas turbines through the development of an advanced three-dimensional and viscous blade design system. This technology is needed to replace some elements in current design systems that are based on outdated technology.
An overview of reliability methods in mechanical and structural design
NASA Technical Reports Server (NTRS)
Wirsching, P. H.; Ortiz, K.; Lee, S. J.
1987-01-01
An evaluation is made of modern methods of fast probability integration and Monte Carlo treatment for the assessment of structural systems' and components' reliability. Fast probability integration methods are noted to be more efficient than Monte Carlo ones. This is judged to be an important consideration when several point probability estimates must be made in order to construct a distribution function. An example illustrating the relative efficiency of the various methods is included.
An efficient multilevel optimization method for engineering design
NASA Technical Reports Server (NTRS)
Vanderplaats, G. N.; Yang, Y. J.; Kim, D. S.
1988-01-01
An efficient multilevel deisgn optimization technique is presented. The proposed method is based on the concept of providing linearized information between the system level and subsystem level optimization tasks. The advantages of the method are that it does not require optimum sensitivities, nonlinear equality constraints are not needed, and the method is relatively easy to use. The disadvantage is that the coupling between subsystems is not dealt with in a precise mathematical manner.
NASA Technical Reports Server (NTRS)
Chen, Shu-cheng, S.
2009-01-01
For the preliminary design and the off-design performance analysis of axial flow turbines, a pair of intermediate level-of-fidelity computer codes, TD2-2 (design; reference 1) and AXOD (off-design; reference 2), are being evaluated for use in turbine design and performance prediction of the modern high performance aircraft engines. TD2-2 employs a streamline curvature method for design, while AXOD approaches the flow analysis with an equal radius-height domain decomposition strategy. Both methods resolve only the flows in the annulus region while modeling the impact introduced by the blade rows. The mathematical formulations and derivations involved in both methods are documented in references 3, 4 for TD2-2) and in reference 5 (for AXOD). The focus of this paper is to discuss the fundamental issues of applicability and compatibility of the two codes as a pair of companion pieces, to perform preliminary design and off-design analysis for modern aircraft engine turbines. Two validation cases for the design and the off-design prediction using TD2-2 and AXOD conducted on two existing high efficiency turbines, developed and tested in the NASA/GE Energy Efficient Engine (GE-E3) Program, the High Pressure Turbine (HPT; two stages, air cooled) and the Low Pressure Turbine (LPT; five stages, un-cooled), are provided in support of the analysis and discussion presented in this paper.
Improved methods for classification, prediction, and design of antimicrobial peptides.
Wang, Guangshun
2015-01-01
Peptides with diverse amino acid sequences, structures, and functions are essential players in biological systems. The construction of well-annotated databases not only facilitates effective information management, search, and mining but also lays the foundation for developing and testing new peptide algorithms and machines. The antimicrobial peptide database (APD) is an original construction in terms of both database design and peptide entries. The host defense antimicrobial peptides (AMPs) registered in the APD cover the five kingdoms (bacteria, protists, fungi, plants, and animals) or three domains of life (bacteria, archaea, and eukaryota). This comprehensive database ( http://aps.unmc.edu/AP ) provides useful information on peptide discovery timeline, nomenclature, classification, glossary, calculation tools, and statistics. The APD enables effective search, prediction, and design of peptides with antibacterial, antiviral, antifungal, antiparasitic, insecticidal, spermicidal, anticancer activities, chemotactic, immune modulation, or antioxidative properties. A universal classification scheme is proposed herein to unify innate immunity peptides from a variety of biological sources. As an improvement, the upgraded APD makes predictions based on the database-defined parameter space and provides a list of the sequences most similar to natural AMPs. In addition, the powerful pipeline design of the database search engine laid a solid basis for designing novel antimicrobials to combat resistant superbugs, viruses, fungi, or parasites. This comprehensive AMP database is a useful tool for both research and education. PMID:25555720
Categorizing Student Software Designs: Methods, Results, and Implications
ERIC Educational Resources Information Center
Eckerdal, Anna; McCartney, Robert; Mostrom, Jan Erik; Ratcliffe, Mark; Zander, Carol
2006-01-01
This paper examines the problem of studying and comparing student software designs. We propose semantic categorization as a way to organize widely varying data items. We describe how this was used to organize a particular multi-national, multi-institutional dataset, and present the results of this analysis: most students are unable to effectively…
A Prospective Method to Guide Small Molecule Drug Design
ERIC Educational Resources Information Center
Johnson, Alan T.
2015-01-01
At present, small molecule drug design follows a retrospective path when considering what analogs are to be made around a current hit or lead molecule with the focus often on identifying a compound with higher intrinsic potency. What this approach overlooks is the simultaneous need to also improve the physicochemical (PC) and pharmacokinetic (PK)…
Study of design and analysis methods for transonic flow
NASA Technical Reports Server (NTRS)
Murman, E. M.
1977-01-01
An airfoil design program and a boundary layer analysis were developed. Boundary conditions were derived for ventilated transonic wind tunnels and performing transonic windtunnel wall calculations. A computational procedure for rotational transonic flow in engine inlet throats was formulated. Results and conclusions are summarized.
COPTRAN - A method of optimum communication systems design
NASA Technical Reports Server (NTRS)
Brinkman, K. L.; Pratt, W. K.; Stokes, L. S.; Weber, J. W.
1970-01-01
Single set of mathematical expressions describes system cost and probability of error of data transmission in terms of four basic parameters in the link equation. A Lagrange multiplier sets up equations whose solutions yield the optimum values for system design considerations and weight and cost values.
Library Design Analysis Using Post-Occupancy Evaluation Methods.
ERIC Educational Resources Information Center
James, Dennis C.; Stewart, Sharon L.
1995-01-01
Presents findings of a user-based study of the interior of Rodger's Science and Engineering Library at the University of Alabama. Compared facility evaluations from faculty, library staff, and graduate and undergraduate students. Features evaluated include: acoustics, aesthetics, book stacks, design, finishes/materials, furniture, lighting,…
Improved Methods for Classification, Prediction and Design of Antimicrobial Peptides
Wang, Guangshun
2015-01-01
Peptides with diverse amino acid sequences, structures and functions are essential players in biological systems. The construction of well-annotated databases not only facilitates effective information management, search and mining, but also lays the foundation for developing and testing new peptide algorithms and machines. The antimicrobial peptide database (APD) is an original construction in terms of both database design and peptide entries. The host defense antimicrobial peptides (AMPs) registered in the APD cover the five kingdoms (bacteria, protists, fungi, plants, and animals) or three domains of life (bacteria, archaea, and eukaryota). This comprehensive database (http://aps.unmc.edu/AP) provides useful information on peptide discovery timeline, nomenclature, classification, glossary, calculation tools, and statistics. The APD enables effective search, prediction, and design of peptides with antibacterial, antiviral, antifungal, antiparasitic, insecticidal, spermicidal, anticancer activities, chemotactic, immune modulation, or anti-oxidative properties. A universal classification scheme is proposed herein to unify innate immunity peptides from a variety of biological sources. As an improvement, the upgraded APD makes predictions based on the database-defined parameter space and provides a list of the sequences most similar to natural AMPs. In addition, the powerful pipeline design of the database search engine laid a solid basis for designing novel antimicrobials to combat resistant superbugs, viruses, fungi or parasites. This comprehensive AMP database is a useful tool for both research and education. PMID:25555720
Overview of control design methods for smart structural system
NASA Astrophysics Data System (ADS)
Rao, Vittal S.; Sana, Sridhar
2001-08-01
Smart structures are a result of effective integration of control system design and signal processing with the structural systems to maximally utilize the new advances in materials for structures, actuation and sensing to obtain the best performance for the application at hand. The research in smart structures is constantly driving towards attaining self adaptive and diagnostic capabilities that biological systems possess. This has been manifested in the number of successful applications in many areas of engineering such as aerospace, civil and automotive systems. Instrumental in the development of such systems are smart materials such as piezo-electric, shape memory alloys, electrostrictive, magnetostrictive and fiber-optic materials and various composite materials for use as actuators, sensors and structural members. The need for development of control systems that maximally utilize the smart actuators and sensing materials to design highly distributed and highly adaptable controllers has spurred research in the area of smart structural modeling, identification, actuator/sensor design and placement, control systems design such as adaptive and robust controllers with new tools such a neural networks, fuzzy logic, genetic algorithms, linear matrix inequalities and electronics for controller implementation such as analog electronics, micro controllers, digital signal processors (DSPs) and application specific integrated circuits (ASICs) such field programmable gate arrays (FPGAs) and Multichip modules (MCMs) etc. In this paper, we give a brief overview of the state of control in smart structures. Different aspects of the development of smart structures such as applications, technology and theoretical advances especially in the area of control systems design and implementation will be covered.
Optimal reliability design method for remote solar systems
NASA Astrophysics Data System (ADS)
Suwapaet, Nuchida
A unique optimal reliability design algorithm is developed for remote communication systems. The algorithm deals with either minimizing an unavailability of the system within a fixed cost or minimizing the cost of the system with an unavailability constraint. The unavailability of the system is a function of three possible failure occurrences: individual component breakdown, solar energy deficiency (loss of load probability), and satellite/radio transmission loss. The three mathematical models of component failure, solar power failure, transmission failure are combined and formulated as a nonlinear programming optimization problem with binary decision variables, such as number and type (or size) of photovoltaic modules, batteries, radios, antennas, and controllers. Three possible failures are identified and integrated in computer algorithm to generate the parameters for the optimization algorithm. The optimization algorithm is implemented with a branch-and-bound technique solution in MS Excel Solver. The algorithm is applied to a case study design for an actual system that will be set up in remote mountainous areas of Peru. The automated algorithm is verified with independent calculations. The optimal results from minimizing the unavailability of the system with the cost constraint case and minimizing the total cost of the system with the unavailability constraint case are consistent with each other. The tradeoff feature in the algorithm allows designers to observe results of 'what-if' scenarios of relaxing constraint bounds, thus obtaining the most benefit from the optimization process. An example of this approach applied to an existing communication system in the Andes shows dramatic improvement in reliability for little increase in cost. The algorithm is a real design tool, unlike other existing simulation design tools. The algorithm should be useful for other stochastic systems where component reliability, random supply and demand, and communication are
Applications of Genetic Methods to NASA Design and Operations Problems
NASA Technical Reports Server (NTRS)
Laird, Philip D.
1996-01-01
We review four recent NASA-funded applications in which evolutionary/genetic methods are important. In the process we survey: the kinds of problems being solved today with these methods; techniques and tools used; problems encountered; and areas where research is needed. The presentation slides are annotated briefly at the top of each page.
Chen, Deng-kai; Gu, Rong; Gu, Yu-feng; Yu, Sui-huai
2016-01-01
Consumers' Kansei needs reflect their perception about a product and always consist of a large number of adjectives. Reducing the dimension complexity of these needs to extract primary words not only enables the target product to be explicitly positioned, but also provides a convenient design basis for designers engaging in design work. Accordingly, this study employs a numerical design structure matrix (NDSM) by parameterizing a conventional DSM and integrating genetic algorithms to find optimum Kansei clusters. A four-point scale method is applied to assign link weights of every two Kansei adjectives as values of cells when constructing an NDSM. Genetic algorithms are used to cluster the Kansei NDSM and find optimum clusters. Furthermore, the process of the proposed method is presented. The details of the proposed approach are illustrated using an example of electronic scooter for Kansei needs clustering. The case study reveals that the proposed method is promising for clustering Kansei needs adjectives in product emotional design.
Design and ergonomics. Methods for integrating ergonomics at hand tool design stage.
Marsot, Jacques; Claudon, Laurent
2004-01-01
As a marked increase in the number of musculoskeletal disorders was noted in many industrialized countries and more specifically in companies that require the use of hand tools, the French National Research and Safety Institute (INRS) launched in 1999 a research project on the topic of integrating ergonomics into hand tool design, and more particularly to a design of a boning knife. After a brief recall of the difficulties of integrating ergonomics at the design stage, the present paper shows how 3 design methodological tools--Functional Analysis, Quality Function Deployment and TRIZ--have been applied to the design of a boning knife. Implementation of these tools enabled us to demonstrate the extent to which they are capable of responding to the difficulties of integrating ergonomics into product design. PMID:15028190
Design component method for sensitivity analysis of built-up structures
NASA Technical Reports Server (NTRS)
Choi, Kyung K.; Seong, Hwai G.
1986-01-01
A 'design component method' that provides a unified and systematic organization of design sensitivity analysis for built-up structures is developed and implemented. Both conventional design variables, such as thickness and cross-sectional area, and shape design variables of components of built-up structures are considered. It is shown that design of components of built-up structures can be characterized and system design sensitivity expressions obtained by simply adding contributions from each component. The method leads to a systematic organization of computations for design sensitivity analysis that is similar to the way in which computations are organized within a finite element code.
Inverse airfoil design procedure using a multigrid Navier-Stokes method
NASA Technical Reports Server (NTRS)
Malone, J. B.; Swanson, R. C.
1991-01-01
The Modified Garabedian McFadden (MGM) design procedure was incorporated into an existing 2-D multigrid Navier-Stokes airfoil analysis method. The resulting design method is an iterative procedure based on a residual correction algorithm and permits the automated design of airfoil sections with prescribed surface pressure distributions. The new design method, Multigrid Modified Garabedian McFadden (MG-MGM), is demonstrated for several different transonic pressure distributions obtained from both symmetric and cambered airfoil shapes. The airfoil profiles generated with the MG-MGM code are compared to the original configurations to assess the capabilities of the inverse design method.
NASA Technical Reports Server (NTRS)
Capo, M. A.; Disney, R. K.; Jordan, T. A.; Soltesz, R. G.; Woodsum, H. C.
1969-01-01
Eight computer programs make up a nine volume synthesis containing two design methods for nuclear rocket radiation shields. The first design method is appropriate for parametric and preliminary studies, while the second accomplishes the verification of a final nuclear rocket reactor design.
40 CFR 53.8 - Designation of reference and equivalent methods.
Code of Federal Regulations, 2011 CFR
2011-07-01
... satisfy the applicable requirements of this part shall be designated as a FRM or FEM (as applicable) by... notice indicating that the method has been designated as a FRM or FEM shall be sent to the applicant. (c) The Administrator will maintain a current list of methods designated as FRM or FEM in accordance...
40 CFR 53.8 - Designation of reference and equivalent methods.
Code of Federal Regulations, 2010 CFR
2010-07-01
... satisfy the applicable requirements of this part shall be designated as a FRM or FEM (as applicable) by... notice indicating that the method has been designated as a FRM or FEM shall be sent to the applicant. (c) The Administrator will maintain a current list of methods designated as FRM or FEM in accordance...
ERIC Educational Resources Information Center
Nogry, S.; Jean-Daubias, S.; Guin, N.
2012-01-01
This article deals with evaluating an interactive learning environment (ILE) during the iterative-design process. Various aspects of the system must be assessed and a number of evaluation methods are available. In designing the ILE Ambre-add, several techniques were combined to test and refine the system. In particular, we point out the merits of…
A hybrid nonlinear programming method for design optimization
NASA Technical Reports Server (NTRS)
Rajan, S. D.
1986-01-01
Solutions to engineering design problems formulated as nonlinear programming (NLP) problems usually require the use of more than one optimization technique. Moreover, the interaction between the user (analysis/synthesis) program and the NLP system can lead to interface, scaling, or convergence problems. An NLP solution system is presented that seeks to solve these problems by providing a programming system to ease the user-system interface. A simple set of rules is used to select an optimization technique or to switch from one technique to another in an attempt to detect, diagnose, and solve some potential problems. Numerical examples involving finite element based optimal design of space trusses and rotor bearing systems are used to illustrate the applicability of the proposed methodology.
Simple optimization method for EMI mesh pattern design
NASA Astrophysics Data System (ADS)
Alpman, Mehmet Erhan; Senger, Tolga
2014-05-01
Metallic mesh coatings are used on visible and infrared windows and domes widely to provide shielding from EMI (Electromagnetic Interference). In this paper, different EMI mesh geometries are compared with each other regarding various performance parameters. But to decide the best fitting EMI mesh geometry to particular optic system is a little bit complicated issue. Therefore, we try to find a simple optimization methodology to decide best EMI mesh geometry design that fits our particular high performance ISR (Intelligence, Surveillance and Reconnaissance) systems.
Design Method of Fault Detector for Injection Unit
NASA Astrophysics Data System (ADS)
Ochi, Kiyoshi; Saeki, Masami
An injection unit is considered as a speed control system utilizing a reaction-force sensor. Our purpose is to design a fault detector that detects and isolates actuator and sensor faults under the condition that the system is disturbed by a reaction force. First described is the fault detector's general structure. In this system, a disturbance observer that estimates the reaction force is designed for the speed control system in order to obtain the residual signals, and then post-filters that separate the specific frequency elements from the residual signals are applied in order to generate the decision signals. Next, we describe a fault detector designed specifically for a model of the injection unit. It is shown that the disturbance imposed on the decision variables can be made significantly small by appropriate adjustments to the observer bandwidth, and that most of the sensor faults and actuator faults can be detected and some of them can be isolated in the frequency domain by setting the frequency characteristics of the post-filters appropriately. Our result is verified by experiments for an actual injection unit.
14 CFR 161.9 - Designation of noise description methods.
Code of Federal Regulations, 2010 CFR
2010-01-01
... and methods prescribed under appendix A of 14 CFR part 150; and (b) Use of computer models to create noise contours must be in accordance with the criteria prescribed under appendix A of 14 CFR part 150....
14 CFR 161.9 - Designation of noise description methods.
Code of Federal Regulations, 2014 CFR
2014-01-01
... and methods prescribed under appendix A of 14 CFR part 150; and (b) Use of computer models to create noise contours must be in accordance with the criteria prescribed under appendix A of 14 CFR part 150....
Object-oriented design of preconditioned iterative methods
Bruaset, A.M.
1994-12-31
In this talk the author discusses how object-oriented programming techniques can be used to develop a flexible software package for preconditioned iterative methods. The ideas described have been used to implement the linear algebra part of Diffpack, which is a collection of C++ class libraries that provides high-level tools for the solution of partial differential equations. In particular, this software package is aimed at rapid development of PDE-based numerical simulators, primarily using finite element methods.
Reducing Design Risk Using Robust Design Methods: A Dual Response Surface Approach
NASA Technical Reports Server (NTRS)
Unal, Resit; Yeniay, Ozgur; Lepsch, Roger A. (Technical Monitor)
2003-01-01
Space transportation system conceptual design is a multidisciplinary process containing considerable element of risk. Risk here is defined as the variability in the estimated (output) performance characteristic of interest resulting from the uncertainties in the values of several disciplinary design and/or operational parameters. Uncertainties from one discipline (and/or subsystem) may propagate to another, through linking parameters and the final system output may have a significant accumulation of risk. This variability can result in significant deviations from the expected performance. Therefore, an estimate of variability (which is called design risk in this study) together with the expected performance characteristic value (e.g. mean empty weight) is necessary for multidisciplinary optimization for a robust design. Robust design in this study is defined as a solution that minimizes variability subject to a constraint on mean performance characteristics. Even though multidisciplinary design optimization has gained wide attention and applications, the treatment of uncertainties to quantify and analyze design risk has received little attention. This research effort explores the dual response surface approach to quantify variability (risk) in critical performance characteristics (such as weight) during conceptual design.
Advanced Control and Protection system Design Methods for Modular HTGRs
Ball, Sydney J; Wilson Jr, Thomas L; Wood, Richard Thomas
2012-06-01
The project supported the Nuclear Regulatory Commission (NRC) in identifying and evaluating the regulatory implications concerning the control and protection systems proposed for use in the Department of Energy's (DOE) Next-Generation Nuclear Plant (NGNP). The NGNP, using modular high-temperature gas-cooled reactor (HTGR) technology, is to provide commercial industries with electricity and high-temperature process heat for industrial processes such as hydrogen production. Process heat temperatures range from 700 to 950 C, and for the upper range of these operation temperatures, the modular HTGR is sometimes referred to as the Very High Temperature Reactor or VHTR. Initial NGNP designs are for operation in the lower temperature range. The defining safety characteristic of the modular HTGR is that its primary defense against serious accidents is to be achieved through its inherent properties of the fuel and core. Because of its strong negative temperature coefficient of reactivity and the capability of the fuel to withstand high temperatures, fast-acting active safety systems or prompt operator actions should not be required to prevent significant fuel failure and fission product release. The plant is designed such that its inherent features should provide adequate protection despite operational errors or equipment failure. Figure 1 shows an example modular HTGR layout (prismatic core version), where its inlet coolant enters the reactor vessel at the bottom, traversing up the sides to the top plenum, down-flow through an annular core, and exiting from the lower plenum (hot duct). This research provided NRC staff with (a) insights and knowledge about the control and protection systems for the NGNP and VHTR, (b) information on the technologies/approaches under consideration for use in the reactor and process heat applications, (c) guidelines for the design of highly integrated control rooms, (d) consideration for modeling of control and protection system designs for
NASA Astrophysics Data System (ADS)
Quintana, Christopher
Learner-centered design is an evolving software design perspective addressing the needs of learners---a specific audience trying to work in and understand new work practices in which they have a novice or naive understanding. Learner-centered design involves designing software that incorporates work support features (or scaffolding features) informed by social constructivist learning theories. By adopting a constructivist "learning by doing" perspective, scaffolds should support learners so they can mindfully engage in previously inaccessible work activity, which in turn allows those learners to progressively gain a better understanding of the new work. While there is an intuitive notion of "learner-centered design", there is less specific design information for developing learner-centered software. As a result, learner-centered software results from "educated guesses" and ad-hoc design approaches rather than from systematic design methods. Thus there is a need for specific design guidance to facilitate the development of learner-centered tools that help learners see the tasks, terminology, tools, etc. in the new work context and engage in that work. The research in this dissertation provides a more specific base of learner-centered design descriptions, methods, and guidelines to analyze work practices and design and evaluate scaffolds. The research approach involves using the development of Symphony---a scaffolded integrated tool environment for high-school students learning the work of computational science inquiry---as a case study to develop the learner-centered design approach. Symphony incorporates a variety of science tools with process scaffolding to support students in performing complex air pollution investigations. Six ninth-grade students used Symphony to investigate air quality questions for several weeks in an environmental science class. The student testing helped assess the effectiveness of the software scaffolding and in turn, the learner
Photovoltaic module hot spot durability design and test methods
NASA Technical Reports Server (NTRS)
Arnett, J. C.; Gonzalez, C. C.
1981-01-01
As part of the Jet Propulsion Laboratory's Low-Cost Solar Array Project, the susceptibility of fat-plate modules to hot-spot problems is investigated. Hot-spot problems arise in modules when the cells become back-biased and operate in the negative-voltage quadrant, as a result of short-circuit current mismatch, cell cracking or shadowing. The details of a qualification test for determining the capability of modules of surviving field hot-spot problems and typical results of this test are presented. In addition, recommended circuit-design techniques for improving the module and array reliability with respect to hot-spot problems are presented.
Method of calculating the optimal radioelectronic equipment design
NASA Astrophysics Data System (ADS)
Ermolaev, Yu. P.
1993-05-01
In designing the competitive radio-electronic equipment there inevitably arises the justified optimal constructional decision problem that accounts for many quality indexes. A totality of these quality indexes can be conveniently represented by the vector in a multi-dimensional space, on the coordinate axes of which the specific quantities of all the accountable indexes of quality are laid off. Inevitability of accounting for a variety of quality indexes, when choosing optimal decision, raises a problem of vector (multi-objective) optimization of the object developed.
Genetic-evolution-based optimization methods for engineering design
NASA Technical Reports Server (NTRS)
Rao, S. S.; Pan, T. S.; Dhingra, A. K.; Venkayya, V. B.; Kumar, V.
1990-01-01
This paper presents the applicability of a biological model, based on genetic evolution, for engineering design optimization. Algorithms embodying the ideas of reproduction, crossover, and mutation are developed and applied to solve different types of structural optimization problems. Both continuous and discrete variable optimization problems are solved. A two-bay truss for maximum fundamental frequency is considered to demonstrate the continuous variable case. The selection of locations of actuators in an actively controlled structure, for minimum energy dissipation, is considered to illustrate the discrete variable case.
Evaluation of cabin design based on the method of multiple attribute group decision-making
NASA Astrophysics Data System (ADS)
Li, Xiaowen; Lv, Linlin; Li, Ping
2013-07-01
New century, cabin design has become an important factor affecting the compact capability of modern naval vessels. Traditional cabin design, based on naval rules and designer's subjective feeling and experience, holds that weapons and equipments are more important than habitability. So crew's satisfaction is not high to ships designed by traditional methods. In order to solve this problem, the method of multiple attribute group decision-making was proposed to evaluate the cabin design projects. This method considered many factors affecting cabin design, established a target system, quantified fuzzy factors in cabin design, analyzed the need of crews and gave a reasonable evaluation on cabin design projects. Finally, an illustrative example analysis validates the effectiveness and reliability of this method.
Cathodic protection design using the regression and correlation method
Niembro, A.M.; Ortiz, E.L.G.
1997-09-01
A computerized statistical method which calculates the current demand requirement based on potential measurements for cathodic protection systems is introduced. The method uses the regression and correlation analysis of statistical measurements of current and potentials of the piping network. This approach involves four steps: field potential measurements, statistical determination of the current required to achieve full protection, installation of more cathodic protection capacity with distributed anodes around the plant and examination of the protection potentials. The procedure is described and recommendations for the improvement of the existing and new cathodic protection systems are given.
Computer control of large accelerators, design concepts and methods
NASA Astrophysics Data System (ADS)
Beck, F.; Gormley, M.
1985-03-01
Unlike most of the specialities treated in this volume, control system design is still an art, not a science. This presentation is an attempt to produce a primer for prospective practitioners of this art. A large modern accelerator requires a comprehensive control system for commissioning, machine studies, and day-to-day operation. Faced with the requirement to design a control system for such a machine, the control system architect has a bewildering array of technical devices and techniques at his disposal, and it is our aim in the following chapters to lead him through the characteristics of the problems he will have to face and the practical alternatives available for solving them. We emphasize good system architecture using commercially available hardware and software components, but in addition we discuss the actual control strategies which are to be implemented, since it is at the point of deciding what facilities shall be available that the complexity of the control system and its cost are implicitly decided.
Flight critical system design guidelines and validation methods
NASA Technical Reports Server (NTRS)
Holt, H. M.; Lupton, A. O.; Holden, D. G.
1984-01-01
Efforts being expended at NASA-Langley to define a validation methodology, techniques for comparing advanced systems concepts, and design guidelines for characterizing fault tolerant digital avionics are described with an emphasis on the capabilities of AIRLAB, an environmentally controlled laboratory. AIRLAB has VAX 11/750 and 11/780 computers with an aggregate of 22 Mb memory and over 650 Mb storage, interconnected at 256 kbaud. An additional computer is programmed to emulate digital devices. Ongoing work is easily accessed at user stations by either chronological or key word indexing. The CARE III program aids in analyzing the capabilities of test systems to recover from faults. An additional code, the semi-Markov unreliability program (SURE) generates upper and lower reliability bounds. The AIRLAB facility is mainly dedicated to research on designs of digital flight-critical systems which must have acceptable reliability before incorporation into aircraft control systems. The digital systems would be too costly to submit to a full battery of flight tests and must be initially examined with the AIRLAB simulation capabilities.
Computer control of large accelerators design concepts and methods
Beck, F.; Gormley, M.
1984-05-01
Unlike most of the specialities treated in this volume, control system design is still an art, not a science. These lectures are an attempt to produce a primer for prospective practitioners of this art. A large modern accelerator requires a comprehensive control system for commissioning, machine studies and day-to-day operation. Faced with the requirement to design a control system for such a machine, the control system architect has a bewildering array of technical devices and techniques at his disposal, and it is our aim in the following chapters to lead him through the characteristics of the problems he will have to face and the practical alternatives available for solving them. We emphasize good system architecture using commercially available hardware and software components, but in addition we discuss the actual control strategies which are to be implemented since it is at the point of deciding what facilities shall be available that the complexity of the control system and its cost are implicitly decided. 19 references.
Analysis of health impact inputs to the US Department of Energy's risk information system
Droppo, J.G. Jr.; Buck, J.W.; Strenge, D.L.; Siegel, M.R.
1990-08-01
The US Department of Energy (DOE) is in the process of completing a survey of environmental problems, referred to as the Environmental Survey, at their facilities across the country. The DOE Risk Information System (RIS) is being used to prioritize these environmental problems identified in the Environmental Survey's findings. This report contains a discussion of site-specific public health risk parameters and the rationale for their inclusion in the RIS. These parameters are based on computed potential impacts obtained with the Multimedia Environmental Pollutant Assessment System (MEPAS). MEPAS is a computer-based methodology for evaluating the potential exposures resulting from multimedia environmental transport of hazardous materials. This report has three related objectives: document the role of MEPAS in the RIS framework, report the results of the analysis of alternative risk parameters that led to the current RIS risk parameters, and describe analysis of uncertainties in the risk-related parameters. 20 refs., 17 figs., 10 tabs.
A Proposed Model of Retransformed Qualitative Data within a Mixed Methods Research Design
ERIC Educational Resources Information Center
Palladino, John M.
2009-01-01
Most models of mixed methods research design provide equal emphasis of qualitative and quantitative data analyses and interpretation. Other models stress one method more than the other. The present article is a discourse about the investigator's decision to employ a mixed method design to examine special education teachers' advocacy and…
Mixing Qualitative and Quantitative Methods: Insights into Design and Analysis Issues
ERIC Educational Resources Information Center
Lieber, Eli
2009-01-01
This article describes and discusses issues related to research design and data analysis in the mixing of qualitative and quantitative methods. It is increasingly desirable to use multiple methods in research, but questions arise as to how best to design and analyze the data generated by mixed methods projects. I offer a conceptualization for such…
Haberland, M; Kim, S
2015-01-01
When millions of years of evolution suggest a particular design solution, we may be tempted to abandon traditional design methods and copy the biological example. However, biological solutions do not often translate directly into the engineering domain, and even when they do, copying eliminates the opportunity to improve. A better approach is to extract design principles relevant to the task of interest, incorporate them in engineering designs, and vet these candidates against others. This paper presents the first general framework for determining whether biologically inspired relationships between design input variables and output objectives and constraints are applicable to a variety of engineering systems. Using optimization and statistics to generalize the results beyond a particular system, the framework overcomes shortcomings observed of ad hoc methods, particularly those used in the challenging study of legged locomotion. The utility of the framework is demonstrated in a case study of the relative running efficiency of rotary-kneed and telescoping-legged robots. PMID:25643176
Category's analysis and operational project capacity method of transformation in design
NASA Astrophysics Data System (ADS)
Obednina, S. V.; Bystrova, T. Y.
2015-10-01
The method of transformation is attracting widespread interest in fields such contemporary design. However, in theory of design little attention has been paid to a categorical status of the term "transformation". This paper presents the conceptual analysis of transformation based on the theory of form employed in the influential essays by Aristotle and Thomas Aquinas. In the present work the transformation as a method of shaping design has been explored as well as potential application of this term in design has been demonstrated.
Power Analysis for Complex Mediational Designs Using Monte Carlo Methods
ERIC Educational Resources Information Center
Thoemmes, Felix; MacKinnon, David P.; Reiser, Mark R.
2010-01-01
Applied researchers often include mediation effects in applications of advanced methods such as latent variable models and linear growth curve models. Guidance on how to estimate statistical power to detect mediation for these models has not yet been addressed in the literature. We describe a general framework for power analyses for complex…
The Use of Hermeneutics in a Mixed Methods Design
ERIC Educational Resources Information Center
von Zweck, Claudia; Paterson, Margo; Pentland, Wendy
2008-01-01
Combining methods in a single study is becoming a more common practice because of the limitations of using only one approach to fully address all aspects of a research question. Hermeneutics in this paper is discussed in relation to a large national study that investigated issues influencing the ability of international graduates to work as…
Application of Six Sigma Method to EMS Design
NASA Astrophysics Data System (ADS)
Rusko, Miroslav; Králiková, Ružena
2011-01-01
The Six Sigma method is a complex and flexible system of achieving, maintaining and maximizing the business success. Six Sigma is based mainly on understanding the customer needs and expectation, disciplined use of facts and statistics analysis, and responsible approach to managing, improving and establishing new business, manufacturing and service processes.
Fault self-diagnosis designing method of the automotive electronic control system
NASA Astrophysics Data System (ADS)
Ding, Yangyan; Yang, Zhigang; Fu, Xiaolin
2005-12-01
The fault self-diagnosis system is an important component of an the automotive electronic control system. Designers of automotive electronic control systems urgently require or need a complete understanding of the self-diagnosis designing method of the control system in order to apply it in practice. Aiming at this exigent need, self-diagnosis methods of designing sensors, electronic control unit (ECU), and actuators, which are the three main parts of automotive electronic control systems, are discussed in this paper. According to the fault types and characteristics of commonly used sensors, self-diagnosis designing methods of the sensors are discussed. Then fault diagnosis techniques of sensors utilizing signal detection and analytical redundancy are analysed and summarized respectively, from the viewpoint of the self-diagnosis designing method. Also, problems about failure self-diagnosis of ECU are analyzed here. For different fault types of an ECU, setting up a circuit monitoring method and a self-detection method of the hardware circuit are adopted respectively. Using these two methods mentioned above, a real-time and on-line technique of failure self-diagnosis is presented. Furthermore, the failure self-diagnosis design method of ECU are summarized. Finally, common faults of actuators are analyzed and the general design method of the failure self-diagnosis system is presented. It is suggested that self-diagnosis design methods relative to the failure of automotive electronic control systems can offer a useful approach to designers of control systems.
International children's accelerometry database (ICAD): Design and methods
2011-01-01
Background Over the past decade, accelerometers have increased in popularity as an objective measure of physical activity in free-living individuals. Evidence suggests that objective measures, rather than subjective tools such as questionnaires, are more likely to detect associations between physical activity and health in children. To date, a number of studies of children and adolescents across diverse cultures around the globe have collected accelerometer measures of physical activity accompanied by a broad range of predictor variables and associated health outcomes. The International Children's Accelerometry Database (ICAD) project pooled and reduced raw accelerometer data using standardized methods to create comparable outcome variables across studies. Such data pooling has the potential to improve our knowledge regarding the strength of relationships between physical activity and health. This manuscript describes the contributing studies, outlines the standardized methods used to process the accelerometer data and provides the initial questions which will be addressed using this novel data repository. Methods Between September 2008 and May 2010 46,131 raw Actigraph data files and accompanying anthropometric, demographic and health data collected on children (aged 3-18 years) were obtained from 20 studies worldwide and data was reduced using standardized analytical methods. Results When using ≥ 8, ≥ 10 and ≥ 12 hrs of wear per day as a criterion, 96%, 93.5% and 86.2% of the males, respectively, and 96.3%, 93.7% and 86% of the females, respectively, had at least one valid day of data. Conclusions Pooling raw accelerometer data and accompanying phenotypic data from a number of studies has the potential to: a) increase statistical power due to a large sample size, b) create a more heterogeneous and potentially more representative sample, c) standardize and optimize the analytical methods used in the generation of outcome variables, and d) provide a means to
R. W. Youngblood
2010-10-01
The concept of “margin” has a long history in nuclear licensing and in the codification of good engineering practices. However, some traditional applications of “margin” have been carried out for surrogate scenarios (such as design basis scenarios), without regard to the actual frequencies of those scenarios, and have been carried out with in a systematically conservative fashion. This means that the effectiveness of the application of the margin concept is determined in part by the original choice of surrogates, and is limited in any case by the degree of conservatism imposed on the evaluation. In the RISMC project, which is part of the Department of Energy’s “Light Water Reactor Sustainability Program” (LWRSP), we are developing a risk-informed characterization of safety margin. Beginning with the traditional discussion of “margin” in terms of a “load” (a physical challenge to system or component function) and a “capacity” (the capability of that system or component to accommodate the challenge), we are developing the capability to characterize probabilistic load and capacity spectra, reflecting both aleatory and epistemic uncertainty in system response. For example, the probabilistic load spectrum will reflect the frequency of challenges of a particular severity. Such a characterization is required if decision-making is to be informed optimally. However, in order to enable the quantification of probabilistic load spectra, existing analysis capability needs to be extended. Accordingly, the INL is working on a next-generation safety analysis capability whose design will allow for much more efficient parameter uncertainty analysis, and will enable a much better integration of reliability-related and phenomenology-related aspects of margin.
Iterative method of baffle design for modified Ritchey-Chretien telescope.
Senthil Kumar, M; Narayanamurthy, C S; Kiran Kumar, A S
2013-02-20
We developed a baffle design method based on a combination of the results of optical design software and analytical relations formulated herein. The method finds the exact solution for baffle parameters of a modified Ritchey-Chretien telescope by iteratively solving the analytical relations using the actual ray coordinates of the telescope computed with the aid of optical design software. The baffle system so designed not only blocks the direct rays of stray light reaching the image plane but also provides minimum obscuration to imaging light. Based on the iterative method, we proposed a baffle design approach for a rectangular-image-format telescope. PMID:23434995
The research progress on Hodograph Method of aerodynamic design at Tsinghua University
NASA Technical Reports Server (NTRS)
Chen, Zuoyi; Guo, Jingrong
1991-01-01
Progress in the use of the Hodograph method of aerodynamic design is discussed. It was found that there are some restricted conditions in the application of Hodograph design to transonic turbine and compressor cascades. The Hodograph method is suitable not only to the transonic turbine cascade but also to the transonic compressor cascade. The three dimensional Hodograph method will be developed after obtaining the basic equation for the three dimensional Hodograph method. As an example of the Hodograph method, the use of the method to design a transonic turbine and compressor cascade is discussed.
AI/OR computational model for integrating qualitative and quantitative design methods
NASA Technical Reports Server (NTRS)
Agogino, Alice M.; Bradley, Stephen R.; Cagan, Jonathan; Jain, Pramod; Michelena, Nestor
1990-01-01
A theoretical framework for integrating qualitative and numerical computational methods for optimally-directed design is described. The theory is presented as a computational model and features of implementations are summarized where appropriate. To demonstrate the versatility of the methodology we focus on four seemingly disparate aspects of the design process and their interaction: (1) conceptual design, (2) qualitative optimal design, (3) design innovation, and (4) numerical global optimization.
Bumpus, S.E.; Johnson, J.J.; Smith, P.D.
1980-05-01
The concept of how two techniques, Best Estimate Method and Evaluation Method, may be applied to the traditional seismic analysis and design of a nuclear power plant is introduced. Only the four links of the seismic analysis and design methodology chain (SMC) - seismic input, soil-structure interaction, major structural response, and subsystem response - are considered. The objective is to evaluate the compounding of conservatisms in the seismic analysis and design of nuclear power plants, to provide guidance for judgments in the SMC, and to concentrate the evaluation on that part of the seismic analysis and design which is familiar to the engineering community. An example applies the effects of three-dimensional excitations on a model of a nuclear power plant structure. The example demonstrates how conservatisms accrue by coupling two links in the SMC and comparing those results to the effects of one link alone. The utility of employing the Best Estimate Method vs the Evaluation Method is also demonstrated.
Matching wind turbine rotors and loads: computational methods for designers
Seale, J.B.
1983-04-01
This report provides a comprehensive method for matching wind energy conversion system (WECS) rotors with the load characteristics of common electrical and mechanical applications. The user must supply: (1) turbine aerodynamic efficiency as a function of tipspeed ratio; (2) mechanical load torque as a function of rotation speed; (3) useful delivered power as a function of incoming mechanical power; (4) site average windspeed and, for maximum accuracy, distribution data. The description of the data includes governing limits consistent with the capacities of components. The report develops, a step-by-step method for converting the data into useful results: (1) from turbine efficiency and load torque characteristics, turbine power is predicted as a function of windspeed; (2) a decision is made how turbine power is to be governed (it may self-govern) to insure safety of all components; (3) mechanical conversion efficiency comes into play to predict how useful delivered power varies with windspeed; (4) wind statistics come into play to predict longterm energy output. Most systems can be approximated by a graph-and-calculator approach: Computer-generated families of coefficient curves provide data for algebraic scaling formulas. The method leads not only to energy predictions, but also to insight into the processes being modeled. Direct use of a computer program provides more sophisticated calculations where a highly unusual system is to be modeled, where accuracy is at a premium, or where error analysis is required. The analysis is fleshed out witn in-depth case studies for induction generator and inverter utility systems; battery chargers; resistance heaters; positive displacement pumps, including three different load-compensation strategies; and centrifugal pumps with unregulated electric power transmission from turbine to pump.
Design of a Password-Based EAP Method
NASA Astrophysics Data System (ADS)
Manganaro, Andrea; Koblensky, Mingyur; Loreti, Michele
In recent years, amendments to IEEE standards for wireless networks added support for authentication algorithms based on the Extensible Authentication Protocol (EAP). Available solutions generally use digital certificates or pre-shared keys but the management of the resulting implementations is complex or unlikely to be scalable. In this paper we present EAP-SRP-256, an authentication method proposal that relies on the SRP-6 protocol and provides a strong password-based authentication mechanism. It is intended to meet the IETF security and key management requirements for wireless networks.
Simplified tornado depressurization design methods for nuclear power plants
Howard, N.M.; Krasnopoler, M.I.
1983-05-01
A simplified approach for the calculation of tornado depressurization effects on nuclear power plant structures and components is based on a generic computer depressurization analysis for an arbitrary single volume V connected to the atmosphere by an effective vent area A. For a given tornado depressurization transient, the maximum depressurization ..delta..P of the volume was found to depend on the parameter V/A. The relation between ..delta..P and V/A can be represented by a single monotonically increasing curve for each of the three design-basis tornadoes described in the U.S. Nuclear Regulatory Commission's Regulatory Guide 1.76. These curves can be applied to most multiple-volume nuclear power plant structures by considering each volume and its controlling vent area. Where several possible flow areas could be controlling, the maximum value of V/A can be used to estimate a conservative value for ..delta..P. This simplified approach was shown to yield reasonably conservative results when compared to detailed computer calculations of moderately complex geometries. Treatment of severely complicated geometries, heating and ventilation systems, and multiple blowout panel arrangements were found to be beyond the limitations of the simplified analysis.
Defining Requirements and Related Methods for Designing Sensorized Garments.
Andreoni, Giuseppe; Standoli, Carlo Emilio; Perego, Paolo
2016-01-01
Designing smart garments has strong interdisciplinary implications, specifically related to user and technical requirements, but also because of the very different applications they have: medicine, sport and fitness, lifestyle monitoring, workplace and job conditions analysis, etc. This paper aims to discuss some user, textile, and technical issues to be faced in sensorized clothes development. In relation to the user, the main requirements are anthropometric, gender-related, and aesthetical. In terms of these requirements, the user's age, the target application, and fashion trends cannot be ignored, because they determine the compliance with the wearable system. Regarding textile requirements, functional factors-also influencing user comfort-are elasticity and washability, while more technical properties are the stability of the chemical agents' effects for preserving the sensors' efficacy and reliability, and assuring the proper duration of the product for the complete life cycle. From the technical side, the physiological issues are the most important: skin conductance, tolerance, irritation, and the effect of sweat and perspiration are key factors for reliable sensing. Other technical features such as battery size and duration, and the form factor of the sensor collector, should be considered, as they affect aesthetical requirements, which have proven to be crucial, as well as comfort and wearability. PMID:27240361
Defining Requirements and Related Methods for Designing Sensorized Garments
Andreoni, Giuseppe; Standoli, Carlo Emilio; Perego, Paolo
2016-01-01
Designing smart garments has strong interdisciplinary implications, specifically related to user and technical requirements, but also because of the very different applications they have: medicine, sport and fitness, lifestyle monitoring, workplace and job conditions analysis, etc. This paper aims to discuss some user, textile, and technical issues to be faced in sensorized clothes development. In relation to the user, the main requirements are anthropometric, gender-related, and aesthetical. In terms of these requirements, the user’s age, the target application, and fashion trends cannot be ignored, because they determine the compliance with the wearable system. Regarding textile requirements, functional factors—also influencing user comfort—are elasticity and washability, while more technical properties are the stability of the chemical agents’ effects for preserving the sensors’ efficacy and reliability, and assuring the proper duration of the product for the complete life cycle. From the technical side, the physiological issues are the most important: skin conductance, tolerance, irritation, and the effect of sweat and perspiration are key factors for reliable sensing. Other technical features such as battery size and duration, and the form factor of the sensor collector, should be considered, as they affect aesthetical requirements, which have proven to be crucial, as well as comfort and wearability. PMID:27240361
A Computational Method for Materials Design of New Interfaces
NASA Astrophysics Data System (ADS)
Kaminski, Jakub; Ratsch, Christian; Weber, Justin; Haverty, Michael; Shankar, Sadasivan
2015-03-01
We propose a novel computational approach to explore the broad configurational space of possible interfaces formed from known crystal structures to find new heterostructure materials with potentially interesting properties. In a series of steps with increasing complexity and accuracy, the vast number of possible combinations is narrowed down to a limited set of the most promising and chemically compatible candidates. This systematic screening encompasses (i) establishing the geometrical compatibility along multiple crystallographic orientations of two materials, (ii) simple functions eliminating configurations with unfavorable interatomic steric conflicts, (iii) application of empirical and semi-empirical potentials estimating approximate energetics and structures, (iv) use of DFT based quantum-chemical methods to ascertain the final optimal geometry and stability of the interface in question. For efficient high-throughput screening we have developed a new method to calculate surface energies, which allows for fast and systematic treatment of materials terminated with non-polar surfaces. We show that our approach leads to a maximum error around 3% from the exact reference. The representative results from our search protocol will be presented for selected materials including semiconductors and oxides.
Design of a Variational Multiscale Method for Turbulent Compressible Flows
NASA Technical Reports Server (NTRS)
Diosady, Laslo Tibor; Murman, Scott M.
2013-01-01
A spectral-element framework is presented for the simulation of subsonic compressible high-Reynolds-number flows. The focus of the work is maximizing the efficiency of the computational schemes to enable unsteady simulations with a large number of spatial and temporal degrees of freedom. A collocation scheme is combined with optimized computational kernels to provide a residual evaluation with computational cost independent of order of accuracy up to 16th order. The optimized residual routines are used to develop a low-memory implicit scheme based on a matrix-free Newton-Krylov method. A preconditioner based on the finite-difference diagonalized ADI scheme is developed which maintains the low memory of the matrix-free implicit solver, while providing improved convergence properties. Emphasis on low memory usage throughout the solver development is leveraged to implement a coupled space-time DG solver which may offer further efficiency gains through adaptivity in both space and time.
The C8 Health Project: Design, Methods, and Participants
Frisbee, Stephanie J.; Brooks, A. Paul; Maher, Arthur; Flensborg, Patsy; Arnold, Susan; Fletcher, Tony; Steenland, Kyle; Shankar, Anoop; Knox, Sarah S.; Pollard, Cecil; Halverson, Joel A.; Vieira, Verónica M.; Jin, Chuanfang; Leyden, Kevin M.; Ducatman, Alan M.
2009-01-01
Background The C8 Health Project was created, authorized, and funded as part of the settlement agreement reached in the case of Jack W. Leach, et al. v. E.I. du Pont de Nemours & Company (no. 01-C-608 W.Va., Wood County Circuit Court, filed 10 April 2002). The settlement stemmed from the perfluorooctanoic acid (PFOA, or C8) contamination of drinking water in six water districts in two states near the DuPont Washington Works facility near Parkersburg, West Virginia. Objectives This study reports on the methods and results from the C8 Health Project, a population study created to gather data that would allow class members to know their own PFOA levels and permit subsequent epidemiologic investigations. Methods Final study participation was 69,030, enrolled over a 13-month period in 2005–2006. Extensive data were collected, including demographic data, medical diagnoses (both self-report and medical records review), clinical laboratory testing, and determination of serum concentrations of 10 perfluorocarbons (PFCs). Here we describe the processes used to collect, validate, and store these health data. We also describe survey participants and their serum PFC levels. Results The population geometric mean for serum PFOA was 32.91 ng/mL, 500% higher than previously reported for a representative American population. Serum concentrations for perfluorohexane sulfonate and perfluorononanoic acid were elevated 39% and 73% respectively, whereas perfluorooctanesulfonate was present at levels similar to those in the U.S. population. Conclusions This largest known population study of community PFC exposure permits new evaluations of associations between PFOA, in particular, and a range of health parameters. These will contribute to understanding of the biology of PFC exposure. The C8 Health Project also represents an unprecedented effort to gather basic data on an exposed population; its achievements and limitations can inform future legal settlements for populations exposed to
A streamline curvature method for design of supercritical and subcritical airfoils
NASA Technical Reports Server (NTRS)
Barger, R. L.; Brooks, C. W., Jr.
1974-01-01
An airfoil design procedure, applicable to both subcritical and supercritical airfoils, is described. The method is based on the streamline curvature velocity equation. Several examples illustrating this method are presented and discussed.
Modified Fully Utilized Design (MFUD) Method for Stress and Displacement Constraints
NASA Technical Reports Server (NTRS)
Patnaik, Surya; Gendy, Atef; Berke, Laszlo; Hopkins, Dale
1997-01-01
The traditional fully stressed method performs satisfactorily for stress-limited structural design. When this method is extended to include displacement limitations in addition to stress constraints, it is known as the fully utilized design (FUD). Typically, the FUD produces an overdesign, which is the primary limitation of this otherwise elegant method. We have modified FUD in an attempt to alleviate the limitation. This new method, called the modified fully utilized design (MFUD) method, has been tested successfully on a number of designs that were subjected to multiple loads and had both stress and displacement constraints. The solutions obtained with MFUD compare favorably with the optimum results that can be generated by using nonlinear mathematical programming techniques. The MFUD method appears to have alleviated the overdesign condition and offers the simplicity of a direct, fully stressed type of design method that is distinctly different from optimization and optimality criteria formulations. The MFUD method is being developed for practicing engineers who favor traditional design methods rather than methods based on advanced calculus and nonlinear mathematical programming techniques. The Integrated Force Method (IFM) was found to be the appropriate analysis tool in the development of the MFUD method. In this paper, the MFUD method and its optimality are presented along with a number of illustrative examples.
Rational method for design of wick drain systems
NASA Astrophysics Data System (ADS)
Landau, Richard E.
the time to complete 90% of primary consolidation in the field. Procedures are described to determine the field induced pore pressure profile needed to apply the empirical relationship in design.
Photomask design method for pattern-integrated interference lithography
NASA Astrophysics Data System (ADS)
Leibovici, Matthieu C. R.; Gaylord, Thomas K.
2016-01-01
Pattern-integrated interference lithography (PIIL) combines multibeam interference lithography and projection lithography simultaneously to produce two-dimensional (2-D) and three-dimensional (3-D) periodic-lattice-based microstructures in a rapid, single-exposure step. Using a comprehensive PIIL vector model and realistic photolithographic conditions, PIIL exposures for a representative photonic-crystal (PhC) 90 deg bend waveguide are simulated in the volume of the photoresist film. The etched structures in the underlying substrate are estimated as well. Due to the imperfect integration of the photomask within the interference pattern, the interference pattern is locally distorted, thereby impacting the PhC periodic lattice and potentially the device performance. To mitigate these distortions, a photomask optimization method for PIIL is presented in this work. With an improved photomask, pillar-area and pillar-displacement errors in the vicinity of the waveguide are reduced by factors of 3.3 and 2.7, respectively. Furthermore, calculated transmission spectra show that the performance of the PIIL-produced PhC device is as good as that of its idealized equivalent.
A Computational Method for Materials Design of Interfaces
NASA Astrophysics Data System (ADS)
Kaminski, Jakub; Ratsch, Christian; Shankar, Sadasivan
2014-03-01
In the present work we propose a novel computational approach to explore the broad configurational space of possible interfaces formed from known crystal structures to find new hetrostructure materials with potentially interesting properties. In the series of subsequent steps with increasing complexity and accuracy, the vast number of possible combinations is narrowed down to a limited set of the most promising and chemically compatible candidates. This systematic screening encompasses (i) establishing the geometrical compatibility along multiple crystallographic orientations of two (or more) materials, (ii) simple functions eliminating configurations with unfavorable interatomic steric conflicts, (iii) application of empirical and semi-empirical potentials estimating approximate energetics and structures, (iv) use of DFT based quantum-chemical methods to ascertain the final optimal geometry and stability of the interface in question. We also demonstrate the flexibility and efficiency of our approach depending on the size of the investigated structures and size of the search space. The representative results from our search protocol will be presented for selected materials including semiconductors, transition metal systems, and oxides.
Unique Method for Generating Design Earthquake Time History Seeds
R. E. Spears
2008-07-01
A method has been developed which takes a single seed earthquake time history and produces multiple similar seed earthquake time histories. These new time histories possess important frequency and cumulative energy attributes of the original while having a correlation less than 30% (per the ASCE/SEI 43-05 Section 2.4 [1]). They are produced by taking the fast Fourier transform of the original seed. The averaged amplitudes are then pared with random phase angles and the inverse fast Fourier transform is taken to produce a new time history. The average amplitude through time is then adjusted to encourage a similar cumulative energy curve. Next, the displacement is modified to approximate the original curve using Fourier techniques. Finally, the correlation is checked to ensure it is less than 30%. This process does not guarantee that the correlation will be less than 30% for all of a given set of new curves. It does provide a simple tool where a few additional iterations of the process should produce a set of seed earthquake time histories meeting the correlation criteria.
Design method for automotive high-beam LED optics
NASA Astrophysics Data System (ADS)
Byzov, Egor V.; Moiseev, Mikhail A.; Doskolovich, Leonid L.; Kazanskiy, Nikolay L.
2015-09-01
New analytical method for the calculation of the LED secondary optics for automotive high-beam lamps is presented. Automotive headlamps should illuminate the road and the curb at the distance of 100-150 meters and create a bright, flat, relatively powerful light beam. To generate intensity distribution of this kind we propose to use TIR optical element (collimator working on the total internal reflection principle) with array of microlenses (optical corrector) on the upper surface. TIR part of the optical element enables reflection of the side rays to the front direction and provides a collimated beam which incidents on the microrelief. Microrelief, in its turn, dissipates the light flux in horizontal direction to meet the requirements of the Regulations 112, 113 and to provide well-illuminated area across the road in the far field. As an example, we computed and simulated the optical element with the diameter of 33 millimeters and the height of 22 millimeters. Simulation data shows that three illuminating modules including Cree XP-G2 LED and lens allow generating an appropriate intensity distribution for the class D of UNECE Regulations.
Mixture design and treatment methods for recycling contaminated sediment.
Wang, Lei; Kwok, June S H; Tsang, Daniel C W; Poon, Chi-Sun
2015-01-01
Conventional marine disposal of contaminated sediment presents significant financial and environmental burden. This study aimed to recycle the contaminated sediment by assessing the roles and integration of binder formulation, sediment pretreatment, curing method, and waste inclusion in stabilization/solidification. The results demonstrated that the 28-d compressive strength of sediment blocks produced with coal fly ash and lime partially replacing cement at a binder-to-sediment ratio of 3:7 could be used as fill materials for construction. The X-ray diffraction analysis revealed that hydration products (calcium hydroxide) were difficult to form at high sediment content. Thermal pretreatment of sediment removed 90% of indigenous organic matter, significantly increased the compressive strength, and enabled reuse as non-load-bearing masonry units. Besides, 2-h CO2 curing accelerated early-stage carbonation inside the porous structure, sequestered 5.6% of CO2 (by weight) in the sediment blocks, and acquired strength comparable to 7-d curing. Thermogravimetric analysis indicated substantial weight loss corresponding to decomposition of poorly and well crystalline calcium carbonate. Moreover, partial replacement of contaminated sediment by various granular waste materials notably augmented the strength of sediment blocks. The metal leachability of sediment blocks was minimal and acceptable for reuse. These results suggest that contaminated sediment should be viewed as useful resources. PMID:25464304
Artificial Instruction. A Method for Relating Learning Theory to Instructional Design.
ERIC Educational Resources Information Center
Ohlsson, Stellan
Prior research on learning has been linked to instruction by the derivation of general principles of instructional design from learning theories. However, such design principles are often difficult to apply to particular instructional issues. A new method for relating research on learning to instructional design is proposed: Different ways of…
Assessing Adaptive Instructional Design Tools and Methods in ADAPT[IT].
ERIC Educational Resources Information Center
Eseryel, Deniz; Spector, J. Michael
ADAPT[IT] (Advanced Design Approach for Personalized Training - Interactive Tools) is a European project within the Information Society Technologies program that is providing design methods and tools to guide a training designer according to the latest cognitive science and standardization principles. ADAPT[IT] addresses users in two significantly…
What Informs Practice and What Is Valued in Corporate Instructional Design? A Mixed Methods Study
ERIC Educational Resources Information Center
Thompson-Sellers, Ingrid N.
2012-01-01
This study used a two-phased explanatory mixed-methods design to explore in-depth what factors are perceived by Instructional Design and Technology (IDT) professionals as impacting instructional design practice, how these factors are valued in the field, and what differences in perspectives exist between IDT managers and non-managers. For phase 1…
Matching Learning Style Preferences with Suitable Delivery Methods on Textile Design Programmes
ERIC Educational Resources Information Center
Sayer, Kate; Studd, Rachel
2006-01-01
Textile design is a subject that encompasses both design and technology; aesthetically pleasing patterns and forms must be set within technical parameters to create successful fabrics. When considering education methods in design programmes, identifying the most relevant learning approach is key to creating future successes. Yet are the most…
NASA Technical Reports Server (NTRS)
Leininger, G. G.
1981-01-01
Using nonlinear digital simulation as a representative model of the dynamic operation of the QCSEE turbofan engine, a feedback control system is designed by variable frequency design techniques. Transfer functions are generated for each of five power level settings covering the range of operation from approach power to full throttle (62.5% to 100% full power). These transfer functions are then used by an interactive control system design synthesis program to provide a closed loop feedback control using the multivariable Nyquist array and extensions to multivariable Bode diagrams and Nichols charts.
Reeder, Blaine; Turner, Anne M
2011-01-01
Responding to public health emergencies requires rapid and accurate assessment of workforce availability under adverse and changing circumstances. However, public health information systems to support resource management during both routine and emergency operations are currently lacking. We applied scenario-based design as an approach to engage public health practitioners in the creation and validation of an information design to support routine and emergency public health activities. Methods: Using semi-structured interviews we identified the information needs and activities of senior public health managers of a large municipal health department during routine and emergency operations. Results: Interview analysis identified twenty-five information needs for public health operations management. The identified information needs were used in conjunction with scenario-based design to create twenty-five scenarios of use and a public health manager persona. Scenarios of use and persona were validated and modified based on follow-up surveys with study participants. Scenarios were used to test and gain feedback on a pilot information system. Conclusion: The method of scenario-based design was applied to represent the resource management needs of senior-level public health managers under routine and disaster settings. Scenario-based design can be a useful tool for engaging public health practitioners in the design process and to validate an information system design. PMID:21807120
Application of concurrent engineering methods to the design of an autonomous aerial robot
NASA Astrophysics Data System (ADS)
Ingalls, Stephen A.
1991-12-01
This paper documents the year-long efforts of a multidisciplinary design team to design, build, and support an autonomous aerial robotics system. The system was developed to participate in the Association for Unmanned Vehicle System's (AUVS) First International Aerial Robotics Competition which was held in Atlanta, Georgia on the Georgia Tech campus on July 29th, 1991. As development time and budget were extremely limited, the team elected to attempt the design using concurrent engineering design methods. These methods were validated in an IDA study by Winner 1 in the late- 1980's to be particularly adept at handling the difficulties to design presented by these limitations.
Design studies for the transmission simulator method of experimental dynamic substructuring.
Mayes, Randall Lee; Arviso, Michael
2010-05-01
In recent years, a successful method for generating experimental dynamic substructures has been developed using an instrumented fixture, the transmission simulator. The transmission simulator method solves many of the problems associated with experimental substructuring. These solutions effectively address: (1) rotation and moment estimation at connection points; (2) providing substructure Ritz vectors that adequately span the connection motion space; and (3) adequately addressing multiple and continuous attachment locations. However, the transmission simulator method may fail if the transmission simulator is poorly designed. Four areas of the design addressed here are: (1) designating response sensor locations; (2) designating force input locations; (3) physical design of the transmission simulator; and (4) modal test design. In addition to the transmission simulator design investigations, a review of the theory with an example problem is presented.
Design of Aspirated Compressor Blades Using Three-dimensional Inverse Method
NASA Technical Reports Server (NTRS)
Dang, T. Q.; Rooij, M. Van; Larosiliere, L. M.
2003-01-01
A three-dimensional viscous inverse method is extended to allow blading design with full interaction between the prescribed pressure-loading distribution and a specified transpiration scheme. Transpiration on blade surfaces and endwalls is implemented as inflow/outflow boundary conditions, and the basic modifications to the method are outlined. This paper focuses on a discussion concerning an application of the method to the design and analysis of a supersonic rotor with aspiration. Results show that an optimum combination of pressure-loading tailoring with surface aspiration can lead to a minimization of the amount of sucked flow required for a net performance improvement at design and off-design operations.
Application of multidisciplinary optimization methods to the design of a supersonic transport
NASA Technical Reports Server (NTRS)
Barthelemy, J.-F. M.; Coen, P. G.; Wrenn, Gregory A.; Riley, M. F.; Dovi, Augustine R.; Hall, L. E.
1991-01-01
An optimization design method is discussed. This method is based on integrating existing disciplinary analysis and sensitivity analysis techniques by means of generalized sensitivity equations. A generic design system implementing this method is described. The system is being used to design the configuration and internal structure of a supersonic transport wing for optimum performance. This problem combines the disciplines of linear aerodynamics, structures, and performance. Initial results which include the disciplines of aerodynamics and structures in a conventional minimum weight design under static aeroelastic constraints are presented.
Launch Vehicle Design and Optimization Methods and Priority for the Advanced Engineering Environment
NASA Technical Reports Server (NTRS)
Rowell, Lawrence F.; Korte, John J.
2003-01-01
NASA's Advanced Engineering Environment (AEE) is a research and development program that will improve collaboration among design engineers for launch vehicle conceptual design and provide the infrastructure (methods and framework) necessary to enable that environment. In this paper, three major technical challenges facing the AEE program are identified, and three specific design problems are selected to demonstrate how advanced methods can improve current design activities. References are made to studies that demonstrate these design problems and methods, and these studies will provide the detailed information and check cases to support incorporation of these methods into the AEE. This paper provides background and terminology for discussing the launch vehicle conceptual design problem so that the diverse AEE user community can participate in prioritizing the AEE development effort.
CEPIAH: A Method for the Design and Evaluation of Pedagogical Hypermedia
ERIC Educational Resources Information Center
Trigano, Philippe C.; Giacomini-Pacurar, Ecaterina
2004-01-01
CEPIAH is a method and a proposal for a Web-based system to be used to assist teachers in designing multimedia documents and in evaluating their prototypes. The proposed tool integrates two modules: one for the Evaluation of Multimedia Pedagogical and Interactive software (EMPI), and the other, a method for designing pedagogical hypermedia…
Applications Of Thin Films In Optics And The Principles And Methods Of Their Design
NASA Astrophysics Data System (ADS)
Knittl, Zdenek
1983-11-01
A review is given of the main application fields of optical thin films and various mathematical methods of their design are briefly characterised, distinguishing between analysis, synthesis, recognition and the graphical methods. Some typical design procedures, such as the use of the Argand diagram, the equivalent layer or of buffering, are demonstrated. Finally, the present and future use of computers is assessed.
INTERMAP: background, aims, design, methods, and descriptive statistics (nondietary).
Stamler, J; Elliott, P; Dennis, B; Dyer, A R; Kesteloot, H; Liu, K; Ueshima, H; Zhou, B F
2003-09-01
Blood pressure (BP) above optimal (< or =120/< or =80 mmHg) is established as a major cardiovascular disease (CVD) risk factor. Prevalence of adverse BP is high in most adult populations; until recently research has been sparse on reasons for this. Since the 1980s, epidemiologic studies confirmed that salt, alcohol intake, and body mass relate directly to BP; dietary potassium, inversely. Several other nutrients also probably influence BP. The DASH feeding trials demonstrated that with the multiple modifications in the DASH combination diet, SBP/DBP (SBP: systolic blood pressure, DBP: diastolic blood pressure) was sizably reduced, independent of calorie balance, alcohol intake, and BP reduction with decreased dietary salt. A key challenge for research is to elucidate specific nutrients accounting for this effect. The general aim of the study was to clarify influences of multiple nutrients on SBP/DBP of individuals over and above effects of Na, K, alcohol, and body mass. Specific aims were, in a cross-sectional epidemiologic study of 4680 men and women aged 40-59 years from 17 diverse population samples in China, Japan, UK, and USA, test 10 prior hypotheses on relations of macronutrients to SBP/DBP and on role of dietary factors in inverse associations of education with BP; test four related subgroup hypotheses; explore associations with SBP/DBP of multiple other nutrients, urinary metabolites, and foods. For these purposes, for all 4680 participants, with standardized high-quality methods, assess individual intake of 76 nutrients from four 24-h dietary recalls/person; measure in two timed 24-h urine collections/person 24-h excretion of Na, K, Ca, Mg, creatinine, amino acids; microalbuminuria; multiple nutrients and metabolites by nuclear magnetic resonance and high-pressure liquid chromatography. Based on eight SBP/DBP measurements/person, and data on multiple possible confounders, utilize mainly multiple linear regression and quantile analyses to test prior
NASA Technical Reports Server (NTRS)
Liu, A. F.
1974-01-01
A systematic approach for applying methods for fracture control in the structural components of space vehicles consists of four major steps. The first step is to define the primary load-carrying structural elements and the type of load, environment, and design stress levels acting upon them. The second step is to identify the potential fracture-critical parts by means of a selection logic flow diagram. The third step is to evaluate the safe-life and fail-safe capabilities of the specified part. The last step in the sequence is to apply the control procedures that will prevent damage to the fracture-critical parts. The fracture control methods discussed include fatigue design and analysis methods, methods for preventing crack-like defects, fracture mechanics analysis methods, and nondestructive evaluation methods. An example problem is presented for evaluation of the safe-crack-growth capability of the space shuttle crew compartment skin structure.
Human Reliability Analysis for Design: Using Reliability Methods for Human Factors Issues
Ronald Laurids Boring
2010-11-01
This paper reviews the application of human reliability analysis methods to human factors design issues. An application framework is sketched in which aspects of modeling typically found in human reliability analysis are used in a complementary fashion to the existing human factors phases of design and testing. The paper provides best achievable practices for design, testing, and modeling. Such best achievable practices may be used to evaluate and human system interface in the context of design safety certifications.
NASA Astrophysics Data System (ADS)
Sparks, Andrew W.; Olson, Craig; Theisen, Michael J.; Addiego, Chris J.; Hutchins, Tiffany G.; Goodman, Timothy D.
2016-05-01
Performance models for infrared imaging systems require image quality parameters; optical design engineers need image quality design goals; systems engineers develop image quality allocations to test imaging systems against. It is a challenge to maintain consistency and traceability amongst the various expressions of image quality. We present a method and parametric tool for generating and managing expressions of image quality during the system modeling, requirements specification, design, and testing phases of an imaging system design and development project.
NASA Technical Reports Server (NTRS)
Unger, Eric R.; Hager, James O.; Agrawal, Shreekant
1999-01-01
This paper is a discussion of the supersonic nonlinear point design optimization efforts at McDonnell Douglas Aerospace under the High-Speed Research (HSR) program. The baseline for these optimization efforts has been the M2.4-7A configuration which represents an arrow-wing technology for the High-Speed Civil Transport (HSCT). Optimization work on this configuration began in early 1994 and continued into 1996. Initial work focused on optimization of the wing camber and twist on a wing/body configuration and reductions of 3.5 drag counts (Euler) were realized. The next phase of the optimization effort included fuselage camber along with the wing and a drag reduction of 5.0 counts was achieved. Including the effects of the nacelles and diverters into the optimization problem became the next focus where a reduction of 6.6 counts (Euler W/B/N/D) was eventually realized. The final two phases of the effort included a large set of constraints designed to make the final optimized configuration more realistic and they were successful albeit with a loss of performance.
A new direct design method for the medium thickness wind turbine airfoil
NASA Astrophysics Data System (ADS)
Wang, Quan; Chen, Jin; Pang, Xiaoping; Li, Songlin; Guo, Xiaofeng
2013-11-01
The newly developed integral function of airfoil profiles based on Trajkovski conformal transform theory could be used to optimize the profiles for the thin thickness airfoil. However, it is hard to adjust the coefficients of the integral function for the medium thickness airfoil. B-spline curve has an advantage of local adjustment, which makes it to effectively control the airfoil profiles at the trailing edge. Therefore, a new direct design method for the medium thickness wind turbine airfoil based on airfoil integral expression and B-spline curve is presented in this paper. An optimal mathematical model of an airfoil is built. Two new airfoils with similar thickness, based on the new designed method and the original integral method, are designed. According to the comparative analysis, the CQU-A25 airfoil designed based on the new method exhibits better results than that of the CQU-I25 airfoil which is designed based on the original method. It is demonstrated that the new method is feasible to design wind turbine airfoils. Meanwhile, the comparison of the aerodynamic performance for the CQU-A25 airfoil and for the DU91-W2-250 airfoil is studied. Results show that the maximum lift coefficient and the maximum lift/drag ratio of the CQU-A25 airfoil are higher than the ones of DU91-W2-250 airfoil in the same condition. This new airfoil design method would make it possible to design other airfoils with different thicknesses.
Risk-Informed Decision Making; Application to the Technology Development Alternative Selection
NASA Astrophysics Data System (ADS)
Dezfuli, Homayoon; Maggio, Gaspare; Everett, Christopher
2010-09-01
NASA NPR 8000.4A, Agency Risk Management Procedural Requirements, defines risk management in terms of two complementary processes: Risk-informed Decision Making(RIDM) and Continuous Risk Management(CRM). The RIDM process is used to inform decision making by emphasizing proper use of risk analysis to make decisions that impact all mission execution domains(e.g., safety, technical, cost, and schedule) for program/projects and mission support organizations. The RIDM process supports the selection of an alternative prior to program commitment. The CRM process is used to manage risk associated with the implementation of the selected alternative. The two processes work together to foster proactive risk management at NASA. The Office of Safety and Mission Assurance at NASA Headquarters has developed a technical handbook to provide guidance for implementing the RIDM process in the context of NASA risk management and systems engineering. This paper summarizes the key concepts and procedures of the RIDM process as presented in the handbook, and also illustrates how the RIDM process can be applied to the selection of technology investments as NASA’s new technology development programs are initiated.
How does the general public evaluate risk information? The impact of associations with other risks.
Visschers, Vivianne H M; Meertens, Ree M; Passchier, Wim F; Devries, Nanne K
2007-06-01
There is a considerable body of knowledge about the way people perceive risks using heuristics and qualitative characteristics, and about how risk information should be communicated to the public. However, little is known about the way people use the perception of known risks (associated risks) to judge an unknown risk. In a first, qualitative study, six different risks were discussed in in-depth interviews and focus group interviews. The interviews showed that risk associations played a prominent role in forming risk perceptions. Associated risks were often mentioned spontaneously. Second, a survey study was conducted to confirm the importance of risk associations quantitatively. This study investigated whether people related unknown risks to known risks. This was indeed confirmed. Furthermore, some insight was gained into how and why people form risk associations. Results showed that the semantic category of the unknown risks was more important in forming associations than the perceived level of risk or specific risk characteristics. These findings were in line with the semantic network theory. Based on these two studies, we recommend using the mental models approach in developing new risk communications. PMID:17640218
Risk-Informed Decision Making: Application to Technology Development Alternative Selection
NASA Technical Reports Server (NTRS)
Dezfuli, Homayoon; Maggio, Gaspare; Everett, Christopher
2010-01-01
NASA NPR 8000.4A, Agency Risk Management Procedural Requirements, defines risk management in terms of two complementary processes: Risk-informed Decision Making (RIDM) and Continuous Risk Management (CRM). The RIDM process is used to inform decision making by emphasizing proper use of risk analysis to make decisions that impact all mission execution domains (e.g., safety, technical, cost, and schedule) for program/projects and mission support organizations. The RIDM process supports the selection of an alternative prior to program commitment. The CRM process is used to manage risk associated with the implementation of the selected alternative. The two processes work together to foster proactive risk management at NASA. The Office of Safety and Mission Assurance at NASA Headquarters has developed a technical handbook to provide guidance for implementing the RIDM process in the context of NASA risk management and systems engineering. This paper summarizes the key concepts and procedures of the RIDM process as presented in the handbook, and also illustrates how the RIDM process can be applied to the selection of technology investments as NASA's new technology development programs are initiated.
A Systematic Composite Service Design Modeling Method Using Graph-Based Theory
Elhag, Arafat Abdulgader Mohammed; Mohamad, Radziah; Aziz, Muhammad Waqar; Zeshan, Furkh
2015-01-01
The composite service design modeling is an essential process of the service-oriented software development life cycle, where the candidate services, composite services, operations and their dependencies are required to be identified and specified before their design. However, a systematic service-oriented design modeling method for composite services is still in its infancy as most of the existing approaches provide the modeling of atomic services only. For these reasons, a new method (ComSDM) is proposed in this work for modeling the concept of service-oriented design to increase the reusability and decrease the complexity of system while keeping the service composition considerations in mind. Furthermore, the ComSDM method provides the mathematical representation of the components of service-oriented design using the graph-based theoryto facilitate the design quality measurement. To demonstrate that the ComSDM method is also suitable for composite service design modeling of distributed embedded real-time systems along with enterprise software development, it is implemented in the case study of a smart home. The results of the case study not only check the applicability of ComSDM, but can also be used to validate the complexity and reusability of ComSDM. This also guides the future research towards the design quality measurement such as using the ComSDM method to measure the quality of composite service design in service-oriented software system. PMID:25928358
A systematic composite service design modeling method using graph-based theory.
Elhag, Arafat Abdulgader Mohammed; Mohamad, Radziah; Aziz, Muhammad Waqar; Zeshan, Furkh
2015-01-01
The composite service design modeling is an essential process of the service-oriented software development life cycle, where the candidate services, composite services, operations and their dependencies are required to be identified and specified before their design. However, a systematic service-oriented design modeling method for composite services is still in its infancy as most of the existing approaches provide the modeling of atomic services only. For these reasons, a new method (ComSDM) is proposed in this work for modeling the concept of service-oriented design to increase the reusability and decrease the complexity of system while keeping the service composition considerations in mind. Furthermore, the ComSDM method provides the mathematical representation of the components of service-oriented design using the graph-based theoryto facilitate the design quality measurement. To demonstrate that the ComSDM method is also suitable for composite service design modeling of distributed embedded real-time systems along with enterprise software development, it is implemented in the case study of a smart home. The results of the case study not only check the applicability of ComSDM, but can also be used to validate the complexity and reusability of ComSDM. This also guides the future research towards the design quality measurement such as using the ComSDM method to measure the quality of composite service design in service-oriented software system. PMID:25928358
Wang, Catharine; Gordon, Erynn S.; Stack, Catharine B.; Liu, Ching-Ti; Norkunas, Tricia; Wawak, Lisa; Christman, Michael F.; Green, Robert C.; Bowen, Deborah J.
2013-01-01
Background Obesity rates in the United States have escalated in recent decades and present a major challenge in public health prevention efforts. Currently, testing to identify genetic risk for obesity is readily available through several direct-to-consumer companies. Despite the availability of this type of testing, there is a paucity of evidence as to whether providing people with personal genetic information on obesity risk will facilitate or impede desired behavioral responses. Purpose We describe the key issues in the design and implementation of a randomized controlled trial examining the clinical utility of providing genetic risk information for obesity. Methods Participants are being recruited from the Coriell Personalized Medicine Collaborative, an ongoing, longitudinal research cohort study designed to determine the utility of personal genome information in health management and clinical decision-making. The primary focus of the ancillary Obesity Risk Communication Study is to determine whether genetic risk information added value to traditional communication efforts for obesity, which are based on lifestyle risk factors. The trial employs a 2x2 factorial design in order to examine the effects of providing genetic risk information for obesity, alone or in combination with lifestyle risk information, on participants’ psychological responses, behavioral intentions, health behaviors, and weight. Results The factorial design generated four experimental arms based on communication of estimated risk to participants: 1) no risk feedback (control), 2) genetic risk only, 3) lifestyle risk only, 4) both genetic and lifestyle risk (combined). Key issues in study design pertained to the selection of algorithms to estimate lifestyle risk and determination of information to be provided to participants assigned to each experimental arm to achieve a balance between clinical standards and methodological rigor. Following the launch of the trial in September 2011
NASA Astrophysics Data System (ADS)
Adrich, Przemysław
2016-05-01
In Part I of this work a new method for designing dual foil electron beam forming systems was introduced. In this method, an optimal configuration of the dual foil system is found by means of a systematic, automatized scan of system performance in function of its parameters. At each point of the scan, Monte Carlo method is used to calculate the off-axis dose profile in water taking into account detailed and complete geometry of the system. The new method, while being computationally intensive, minimizes the involvement of the designer. In this Part II paper, feasibility of practical implementation of the new method is demonstrated. For this, a prototype software tools were developed and applied to solve a real life design problem. It is demonstrated that system optimization can be completed within few hours time using rather moderate computing resources. It is also demonstrated that, perhaps for the first time, the designer can gain deep insight into system behavior, such that the construction can be simultaneously optimized in respect to a number of functional characteristics besides the flatness of the off-axis dose profile. In the presented example, the system is optimized in respect to both, flatness of the off-axis dose profile and the beam transmission. A number of practical issues related to application of the new method as well as its possible extensions are discussed.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 10 Energy 1 2010-01-01 2010-01-01 false Risk-informed categorization and treatment of structures, systems and components for nuclear power reactors. 50.69 Section 50.69 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION FACILITIES Issuance, Limitations, and Conditions of Licenses and Construction Permits §...
Development of direct-inverse 3-D methods for applied transonic aerodynamic wing design and analysis
NASA Technical Reports Server (NTRS)
Carlson, Leland A.
1989-01-01
An inverse wing design method was developed around an existing transonic wing analysis code. The original analysis code, TAWFIVE, has as its core the numerical potential flow solver, FLO30, developed by Jameson and Caughey. Features of the analysis code include a finite-volume formulation; wing and fuselage fitted, curvilinear grid mesh; and a viscous boundary layer correction that also accounts for viscous wake thickness and curvature. The development of the inverse methods as an extension of previous methods existing for design in Cartesian coordinates is presented. Results are shown for inviscid wing design cases in super-critical flow regimes. The test cases selected also demonstrate the versatility of the design method in designing an entire wing or discontinuous sections of a wing.
An inverse problem design method for branched and unbranched axially symmetrical ducts
NASA Technical Reports Server (NTRS)
Nelson, C. D.; Yang, T.
1976-01-01
This paper concerns the potential flow design of axially symmetrical ducts of both circular and annular cross section with or without wall suction or blowing slots. The objective of the work was to develop a method by which such ducts could be designed with directly prescribed wall pressure variation. Previous axially symmetrical design methods applied only to circular cross sectional ducts and required that the pressure distribution be prescribed along the duct centerline and not along the duct wall. The present method uses an inverse problem approach which extends the method of Stanitz to the axially symmetrical case, and an approximation is used to account for the stagnation point in branched duct designs. Two examples of successful designs of diffusers with suction slots are presented.
NASA Astrophysics Data System (ADS)
Tsai, Chung-Yu
2016-07-01
A free-form (FF) surface design method is proposed for a nonaxial-symmetrical projector system comprising an FF reflector and a light source. The profile of the reflector is designed using a nonaxial-symmetrical FF (NFF) surface construction method such that each incident ray is directed in such a way as to form a user-specified image pattern on the target region of the image plane. The light ray paths within the projection system are analyzed using an exact analytical model and a skew-ray tracing approach. The validity of the proposed NFF design method is demonstrated by means of ZEMAX simulations. It is shown that the image pattern formed on the target region of the image plane is in good agreement with that specified by the user. The NFF method is mathematically straightforward and easily implemented in computer code. As such, it provides a useful tool for the design and analysis stages of optical systems design.
A Method for the Constrained Design of Natural Laminar Flow Airfoils
NASA Technical Reports Server (NTRS)
Green, Bradford E.; Whitesides, John L.; Campbell, Richard L.; Mineck, Raymond E.
1996-01-01
A fully automated iterative design method has been developed by which an airfoil with a substantial amount of natural laminar flow can be designed, while maintaining other aerodynamic and geometric constraints. Drag reductions have been realized using the design method over a range of Mach numbers, Reynolds numbers and airfoil thicknesses. The thrusts of the method are its ability to calculate a target N-Factor distribution that forces the flow to undergo transition at the desired location; the target-pressure-N-Factor relationship that is used to reduce the N-Factors in order to prolong transition; and its ability to design airfoils to meet lift, pitching moment, thickness and leading-edge radius constraints while also being able to meet the natural laminar flow constraint. The method uses several existing CFD codes and can design a new airfoil in only a few days using a Silicon Graphics IRIS workstation.
Research design and statistical methods in Pakistan Journal of Medical Sciences (PJMS)
Akhtar, Sohail; Shah, Syed Wadood Ali; Rafiq, M.; Khan, Ajmal
2016-01-01
Objective: This article compares the study design and statistical methods used in 2005, 2010 and 2015 of Pakistan Journal of Medical Sciences (PJMS). Methods: Only original articles of PJMS were considered for the analysis. The articles were carefully reviewed for statistical methods and designs, and then recorded accordingly. The frequency of each statistical method and research design was estimated and compared with previous years. Results: A total of 429 articles were evaluated (n=74 in 2005, n=179 in 2010, n=176 in 2015) in which 171 (40%) were cross-sectional and 116 (27%) were prospective study designs. A verity of statistical methods were found in the analysis. The most frequent methods include: descriptive statistics (n=315, 73.4%), chi-square/Fisher’s exact tests (n=205, 47.8%) and student t-test (n=186, 43.4%). There was a significant increase in the use of statistical methods over time period: t-test, chi-square/Fisher’s exact test, logistic regression, epidemiological statistics, and non-parametric tests. Conclusion: This study shows that a diverse variety of statistical methods have been used in the research articles of PJMS and frequency improved from 2005 to 2015. However, descriptive statistics was the most frequent method of statistical analysis in the published articles while cross-sectional study design was common study design. PMID:27022365
Reliability Engineering and Robust Design: New Methods for Thermal/Fluid Engineering
NASA Astrophysics Data System (ADS)
Cullimore, Brent A.; Tsuyuki, Glenn T.
2002-07-01
Recent years have witnessed more improvement to the SINDA/FLUINT thermohydraulic analyzer than at any other time in its long history. These improvements have included not only expansions in analytic power, but also the additions of high-level modules that offer revolutions in thermal/fluid engineering itself. One such high-level module, "Reliability Engineering," is described in this paper. Reliability Engineering means considering tolerances in design parameters, uncertainties in environments, uncertainties in application (e.g. usage scenarios), and variations in manufacturing as the stochastic phenomena that they are. Using this approach, the probability that a design will achieve its required performance (i.e., the reliability) is calculated, providing an assessment of risk or confidence in the design, and quantifying the amount of over- or under-design present. The design to be evaluated for reliability will likely have been produced using traditional methods. Possibly, the design was generated using the Solver optimizer, another high-level module available in SINDA/FLUINT. Using design optimization, the user quantifies the goals that make one design better than another (mass, efficiency, etc.), and specifies the thresholds or requirements which render a given design viable or useless (exceeding a performance limit, etc.). SINDA/FLUINT then automatically searches for an optimal design. Robust Design means factoring reliability into the development of the design itself: designing for a target reliability and thereby avoiding either costly over-design or dangerous under-design in the first place. Such an approach eliminates a deterministic stack-up of tolerances, worst-case scenarios, safety factors, and margins that have been the traditional approaches for treating uncertainties. In any real system or product, heat transfer and fluid flow play a limited role: there are many other aspects to a successful design than the realm of thermal/fluids that is encompassed
A procedural method for the efficient implementation of full-custom VLSI designs
NASA Technical Reports Server (NTRS)
Belk, P.; Hickey, N.
1987-01-01
An imbedded language system for the layout of very large scale integration (VLSI) circuits is examined. It is shown that through the judicious use of this system, a large variety of circuits can be designed with circuit density and performance comparable to traditional full-custom design methods, but with design costs more comparable to semi-custom design methods. The high performance of this methodology is attributable to the flexibility of procedural descriptions of VLSI layouts and to a number of automatic and semi-automatic tools within the system.
A Government/Industry Summary of the Design Analysis Methods for Vibrations (DAMVIBS) Program
NASA Technical Reports Server (NTRS)
Kvaternik, Raymond G. (Compiler)
1993-01-01
The NASA Langley Research Center in 1984 initiated a rotorcraft structural dynamics program, designated DAMVIBS (Design Analysis Methods for VIBrationS), with the objective of establishing the technology base needed by the rotorcraft industry for developing an advanced finite-element-based dynamics design analysis capability for vibrations. An assessment of the program showed that the DAMVIBS Program has resulted in notable technical achievements and major changes in industrial design practice, all of which have significantly advanced the industry's capability to use and rely on finite-element-based dynamics analyses during the design process.
NASA Technical Reports Server (NTRS)
English, Robert E; Cavicchi, Richard H
1951-01-01
Empirical methods of Ainley and Kochendorfer and Nettles were used to predict performances of nine turbine designs. Measured and predicted performances were compared. Appropriate values of blade-loss parameter were determined for the method of Kochendorfer and Nettles. The measured design-point efficiencies were lower than predicted by as much as 0.09 (Ainley and 0.07 (Kochendorfer and Nettles). For the method of Kochendorfer and Nettles, appropriate values of blade-loss parameter ranged from 0.63 to 0.87 and the off-design performance was accurately predicted.
Layer-by-layer design method for soft-X-ray multilayers
NASA Technical Reports Server (NTRS)
Yamamoto, Masaki; Namioka, Takeshi
1992-01-01
A new design method effective for a nontransparent system has been developed for soft-X-ray multilayers with the aid of graphic representation of the complex amplitude reflectance in a Gaussian plane. The method provides an effective means of attaining the absolute maximum reflectance on a layer-by-layer basis and also gives clear insight into the evolution of the amplitude reflectance on a multilayer as it builds up. An optical criterion is derived for the selection of a proper pair of materials needed for designing a high-reflectance multilayer. Some examples are given to illustrate the usefulness of this design method.
General design method for three-dimensional potential flow fields. 1: Theory
NASA Technical Reports Server (NTRS)
Stanitz, J. D.
1980-01-01
A general design method was developed for steady, three dimensional, potential, incompressible or subsonic-compressible flow. In this design method, the flow field, including the shape of its boundary, was determined for arbitrarily specified, continuous distributions of velocity as a function of arc length along the boundary streamlines. The method applied to the design of both internal and external flow fields, including, in both cases, fields with planar symmetry. The analytic problems associated with stagnation points, closure of bodies in external flow fields, and prediction of turning angles in three dimensional ducts were reviewed.
NASA Technical Reports Server (NTRS)
Zang, Thomas A.; Hemsch, Michael J.; Hilburger, Mark W.; Kenny, Sean P; Luckring, James M.; Maghami, Peiman; Padula, Sharon L.; Stroud, W. Jefferson
2002-01-01
This report consists of a survey of the state of the art in uncertainty-based design together with recommendations for a Base research activity in this area for the NASA Langley Research Center. This report identifies the needs and opportunities for computational and experimental methods that provide accurate, efficient solutions to nondeterministic multidisciplinary aerospace vehicle design problems. Barriers to the adoption of uncertainty-based design methods are identified. and the benefits of the use of such methods are explained. Particular research needs are listed.
ERIC Educational Resources Information Center
Blair, R. Clifford; Higgins, J.J.
1978-01-01
The controversy surrounding regression methods for unbalanced factorial designs is addressed. The statistical hypotheses being tested under the various methods, as well as salient issues in the use of these methods, are discussed. The use of statistical computer packages is also discussed. (Author/JKS)
Use of epidemiologic data in Integrated Risk Information System (IRIS) assessments
Persad, Amanda S.; Cooper, Glinda S.
2008-11-15
In human health risk assessment, information from epidemiologic studies is typically utilized in the hazard identification step of the risk assessment paradigm. However, in the assessment of many chemicals by the Integrated Risk Information System (IRIS), epidemiologic data, both observational and experimental, have also been used in the derivation of toxicological risk estimates (i.e., reference doses [RfD], reference concentrations [RfC], oral cancer slope factors [CSF] and inhalation unit risks [IUR]). Of the 545 health assessments posted on the IRIS database as of June 2007, 44 assessments derived non-cancer or cancer risk estimates based on human data. RfD and RfC calculations were based on a spectrum of endpoints from changes in enzyme activity to specific neurological or dermal effects. There are 12 assessments with IURs based on human data, two assessments that extrapolated human inhalation data to derive CSFs and one that used human data to directly derive a CSF. Lung or respiratory cancer is the most common endpoint for cancer assessments based on human data. To date, only one chemical, benzene, has utilized human data for derivation of all three quantitative risk estimates (i.e., RfC, RfD, and dose-response modeling for cancer assessment). Through examples from the IRIS database, this paper will demonstrate how epidemiologic data have been used in IRIS assessments for both adding to the body of evidence in the hazard identification process and in the quantification of risk estimates in the dose-response component of the risk assessment paradigm.
Hybrid airfoil design methods for full-scale ice accretion simulation
NASA Astrophysics Data System (ADS)
Saeed, Farooq
The objective of this thesis is to develop a design method together with a design philosophy that allows the design of "subscale" or "hybrid" airfoils that simulate fullscale ice accretions. These subscale or hybrid airfoils have full-scale leading edges and redesigned aft-sections. A preliminary study to help develop a design philosophy for the design of hybrid airfoils showed that hybrid airfoils could be designed to simulate full-scale airfoil droplet-impingement characteristics and, therefore, ice accretion. The study showed that the primary objective in such a design should be to determine the aft section profile that provides the circulation necessary for simulating full-scale airfoil droplet-impingement characteristics. The outcome of the study, therefore, reveals circulation control as the main design variable. To best utilize this fact, this thesis describes two innovative airfoil design methods for the design of hybrid airfoils. Of the two design methods, one uses a conventional flap system while the other only suggests the use of boundary-layer control through slot-suction on the airfoil upper surface as a possible alternative for circulation control. The formulation of each of the two design methods is described in detail, and the results from each method are validated using wind-tunnel test data. The thesis demonstrates the capabilities of each method with the help of specific design examples highlighting their application potential. In particular, the flap-system based hybrid airfoil design method is used to demonstrate the design of a half-scale hybrid model of a full-scale airfoil that simulates full-scale ice accretion at both the design and off-design conditions. The full-scale airfoil used is representative of a scaled modern business-jet main wing section. The study suggests some useful advantages of using hybrid airfoils as opposed to full-scale airfoils for a better understanding of the ice accretion process and the related issues. Results
Stability margins in a design method for 2-dimensional recursive digital filters
NASA Astrophysics Data System (ADS)
Crebbin, G.; Attikiouzel, J.
1982-06-01
The present investigation is concerned with the extension of a concept of stability margin introduced by Crebbin and Attikiouzel (1981). When implemented as a constraint in a 2-D filter design problem, the stability margin guarantees stability, and, in addition, has a moderating effect on the behavior in either the frequency or the spatial domain. An investigation is conducted regarding the possibility of incorporating stability margins into available automated design methods, and a description is provided of a design method which uses the simplex algorithm reported by Nelder and Mead (1975). The considered algorithm is well suited to handle the constraints imposed by stability and by stability margins. Attention is given to filter structures, the design program, additional computing time for stability testing, problems of stable-only design methods, and relationships between pole position, frequency response, and spatial response.
Hydrodynamic Optimization Method and Design Code for Stall-Regulated Hydrokinetic Turbine Rotors
Sale, D.; Jonkman, J.; Musial, W.
2009-08-01
This report describes the adaptation of a wind turbine performance code for use in the development of a general use design code and optimization method for stall-regulated horizontal-axis hydrokinetic turbine rotors. This rotor optimization code couples a modern genetic algorithm and blade-element momentum performance code in a user-friendly graphical user interface (GUI) that allows for rapid and intuitive design of optimal stall-regulated rotors. This optimization method calculates the optimal chord, twist, and hydrofoil distributions which maximize the hydrodynamic efficiency and ensure that the rotor produces an ideal power curve and avoids cavitation. Optimizing a rotor for maximum efficiency does not necessarily create a turbine with the lowest cost of energy, but maximizing the efficiency is an excellent criterion to use as a first pass in the design process. To test the capabilities of this optimization method, two conceptual rotors were designed which successfully met the design objectives.
NASA Astrophysics Data System (ADS)
Kobayashi, Takashi; Komoda, Norihisa
The traditional business process design methods, in which the usecase is the most typical, have no useful framework to design the activity sequence with. Therefore, the design efficiency and quality vary widely according to the designer’s experience and skill. In this paper, to solve this problem, we propose the business events and their state transition model (a basic business event model) based on the language/action perspective, which is the result in the cognitive science domain. In the business process design, using this model, we decide event occurrence conditions so that every event synchronizes with each other. We also propose the design pattern to decide the event occurrence condition (a business event improvement strategy). Lastly, we apply the business process design method based on the business event model and the business event improvement strategy to the credit card issue process and estimate its effect.
Iterative method for the design of SLM realizable minimum average correlation energy (MACE) filters
NASA Astrophysics Data System (ADS)
Rajan, P. Karivaratha; Ramakrishnan, R.
1995-03-01
Design of optical pattern recognition filters taking into account the nonideal characteristics of the spatial light modulators on which the filters are implemented is an important research problem. In this paper, an iterative method is developed for the design of SLM constrained minimum average correlation energy (MACE) filters. The algorithm uses a relaxation algorithm in conjunction with Juday's minimum euclidean distance (MED) mapping technique in an iterative manner. The performance of the filter designed using this method was evaluated using computer simulations and the results are compared with a constrained MACE filter designed using a software based on a simulated annealing technique. The new software requires much less computer time than the simulated annealing based software providing comparable response. The time taken by the new algorithm is more than that for the MED mapped design; but, the new algorithm provides less deviation from the specified response for training images than the MED mapped design.
NASA Technical Reports Server (NTRS)
2004-01-01
The grant closure report is organized in the following four chapters: Chapter describes the two research areas Design optimization and Solid mechanics. Ten journal publications are listed in the second chapter. Five highlights is the subject matter of chapter three. CHAPTER 1. The Design Optimization Test Bed CometBoards. CHAPTER 2. Solid Mechanics: Integrated Force Method of Analysis. CHAPTER 3. Five Highlights: Neural Network and Regression Methods Demonstrated in the Design Optimization of a Subsonic Aircraft. Neural Network and Regression Soft Model Extended for PX-300 Aircraft Engine. Engine with Regression and Neural Network Approximators Designed. Cascade Optimization Strategy with Neural network and Regression Approximations Demonstrated on a Preliminary Aircraft Engine Design. Neural Network and Regression Approximations Used in Aircraft Design.
Development of a conceptual flight vehicle design weight estimation method library and documentation
NASA Astrophysics Data System (ADS)
Walker, Andrew S.
The state of the art in estimating the volumetric size and mass of flight vehicles is held today by an elite group of engineers in the Aerospace Conceptual Design Industry. This is not a skill readily accessible or taught in academia. To estimate flight vehicle mass properties, many aerospace engineering students are encouraged to read the latest design textbooks, learn how to use a few basic statistical equations, and plunge into the details of parametric mass properties analysis. Specifications for and a prototype of a standardized engineering "tool-box" of conceptual and preliminary design weight estimation methods were developed to manage the growing and ever-changing body of weight estimation knowledge. This also bridges the gap in Mass Properties education for aerospace engineering students. The Weight Method Library will also be used as a living document for use by future aerospace students. This "tool-box" consists of a weight estimation method bibliography containing unclassified, open-source literature for conceptual and preliminary flight vehicle design phases. Transport aircraft validation cases have been applied to each entry in the AVD Weight Method Library in order to provide a sense of context and applicability to each method. The weight methodology validation results indicate consensus and agreement of the individual methods. This generic specification of a method library will be applicable for use by other disciplines within the AVD Lab, Post-Graduate design labs, or engineering design professionals.
The DDBD Method In The A-Seismic Design of Anchored Diaphragm Walls
Manuela, Cecconi; Vincenzo, Pane; Sara, Vecchietti
2008-07-08
The development of displacement based approaches for earthquake engineering design appears to be very useful and capable to provide improved reliability by directly comparing computed response and expected structural performance. In particular, the design procedure known as the Direct Displacement Based Design (DDBD) method, which has been developed in structural engineering over the past ten years in the attempt to mitigate some of the deficiencies in current force-based design methods, has been shown to be very effective and promising ([1], [2]). The first attempts of application of the procedure to geotechnical engineering and, in particular, earth retaining structures are discussed in [3], [4] and [5]. However in this field, the outcomes of the research need to be further investigated in many aspects. The paper focuses on the application of the DDBD method to anchored diaphragm walls. The results of the DDBD method are discussed in detail in the paper, and compared to those obtained from conventional pseudo-static analyses.
Schurig, David
2007-02-21
I will explain how the transformation design method can yield a material specification that possesses the same electromagnetic behavior as a fairly general set of imagined space-time topologies. This method has been used to design invisibility cloaks, but the method is quite general and can be used to design a wide variety of interesting devices that guide, concentrate or shape electromagnetic fields in ways that would be difficult to manage with other design methodologies. Applications range from stealth to energy conversion and distribution to wireless communications to biomedical imaging. The drawback of the method is the complexity of the material specifications that it produces, which are in general anisotropic and inhomogeneous. Only with recent advances in the field of metamaterials can these specifications be realized. I will discuss how metamaterials accomplish this and what their limitations are, e.g. bandwidth, loss, frequency range etc. I will discuss in detail the recent implementation of an invisibility cloak in the microwave spectrum.
Federal Register 2010, 2011, 2012, 2013, 2014
2013-11-12
... 31, 2011 (76 FR 54326-54341). Two of the new equivalent methods for PM are automated monitoring... meteorological sensor. With or without optional ESTEL analog inputs/outputs, serial link: 1 RS-232/422; USB port... inlet and zero check enabled; sample permeation dryer. Serial link: 2 RS-232; USB port; Ethernet...
Bumpus, S.E.; Johnson, J.J.; Smith, P.D.
1980-07-01
The concept of how two techniques, Best Estimate Method and Evaluation Method, may be applied to the tradditional seismic analysis and design of a nuclear power plant is introduced. Only the four links of the seismic analysis and design methodology chain (SMC)--seismic input, soil-structure interaction, major structural response, and subsystem response--are considered. The objective is to evaluate the compounding of conservatisms in the seismic analysis and design of nuclear power plants, to provide guidance for judgments in the SMC, and to concentrate the evaluation on that part of the seismic analysis and design which is familiar to the engineering community. An example applies the effects of three-dimensional excitations on the model of a nuclear power plant structure. The example demonstrates how conservatisms accrue by coupling two links in the SMC and comparing those results to the effects of one link alone. The utility of employing the Best Estimate Method vs the Evauation Method is also demonstrated.
Curiosity and Pedagogy: A Mixed-Methods Study of Student Experiences in the Design Studio
ERIC Educational Resources Information Center
Smith, Korydon H.
2010-01-01
Curiosity is often considered the foundation of learning. There is, however, little understanding of how (or if) pedagogy in higher education affects student curiosity, especially in the studio setting of architecture, interior design, and landscape architecture. This study used mixed-methods to investigate curiosity among design students in the…
Rationale, Design, and Methods of the Preschool ADHD Treatment Study (PATS)
ERIC Educational Resources Information Center
Kollins, Scott; Greenhill, Laurence; Swanson, James; Wigal, Sharon; Abikoff, Howard; McCracken, James; Riddle, Mark; McGough, James; Vitiello, Benedetto; Wigal, Tim; Skrobala, Anne; Posner, Kelly; Ghuman, Jaswinder; Davies, Mark; Cunningham, Charles; Bauzo, Audrey
2006-01-01
Objective: To describe the rationale and design of the Preschool ADHD Treatment Study (PATS). Method: PATS was a National Institutes of Mental Health-funded, multicenter, randomized, efficacy trial designed to evaluate the short-term (5 weeks) efficacy and long-term (40 weeks) safety of methylphenidate (MPH) in preschoolers with…
Connecting Generations: Developing Co-Design Methods for Older Adults and Children
ERIC Educational Resources Information Center
Xie, Bo; Druin, Allison; Fails, Jerry; Massey, Sheri; Golub, Evan; Franckel, Sonia; Schneider, Kiki
2012-01-01
As new technologies emerge that can bring older adults together with children, little has been discussed by researchers concerning the design methods used to create these new technologies. Giving both children and older adults a voice in a shared design process comes with many challenges. This paper details an exploratory study focusing on…
Paragogy and Flipped Assessment: Experience of Designing and Running a MOOC on Research Methods
ERIC Educational Resources Information Center
Lee, Yenn; Rofe, J. Simon
2016-01-01
This study draws on the authors' first-hand experience of designing, developing and delivering (3Ds) a massive open online course (MOOC) entitled "Understanding Research Methods" since 2014, largely but not exclusively for learners in the humanities and social sciences. The greatest challenge facing us was to design an assessment…
Robust PID Parameter Design for Embedded Temperature Control System Using Taguchi Method
NASA Astrophysics Data System (ADS)
Suzuki, Arata; Sugimoto, Kenji
This paper proposes a robust PID parameter design scheme using Taguchi's robust design method. This scheme is applied to an embedded PID temperature control system which is affected by outside (room) temperature. The effectiveness of this scheme is verified experimentally with a cooking household appliance.
A Typology of Mixed Methods Sampling Designs in Social Science Research
ERIC Educational Resources Information Center
Onwuegbuzie, Anthony J.; Collins, Kathleen M. T.
2007-01-01
This paper provides a framework for developing sampling designs in mixed methods research. First, we present sampling schemes that have been associated with quantitative and qualitative research. Second, we discuss sample size considerations and provide sample size recommendations for each of the major research designs for quantitative and…
A Comparison of Diary Method Variations for Enlightening Form Generation in the Design Process
ERIC Educational Resources Information Center
Babapour, Maral; Rehammar, Bjorn; Rahe, Ulrike
2012-01-01
This paper presents two studies in which an empirical approach was taken to understand and explain form generation and decisions taken in the design process. In particular, the activities addressing aesthetic aspects when exteriorising form ideas in the design process have been the focus of the present study. Diary methods were the starting point…
An Empirical Comparison of Five Linear Equating Methods for the NEAT Design
ERIC Educational Resources Information Center
Suh, Youngsuk; Mroch, Andrew A.; Kane, Michael T.; Ripkey, Douglas R.
2009-01-01
In this study, a data base containing the responses of 40,000 candidates to 90 multiple-choice questions was used to mimic data sets for 50-item tests under the "nonequivalent groups with anchor test" (NEAT) design. Using these smaller data sets, we evaluated the performance of five linear equating methods for the NEAT design with five levels of…
Treatment of Early-Onset Schizophrenia Spectrum Disorders (TEOSS): Rationale, Design, and Methods
ERIC Educational Resources Information Center
McClellan, Jon; Sikich, Linmarie; Findling, Robert L.; Frazier, Jean A.; Vitiello, Benedetto; Hlastala, Stefanie A.; Williams, Emily; Ambler, Denisse; Hunt-Harrison, Tyehimba; Maloney, Ann E.; Ritz, Louise; Anderson, Robert; Hamer, Robert M.; Lieberman, Jeffrey A.
2007-01-01
Objective: The Treatment of Early Onset Schizophrenia Spectrum Disorders Study is a publicly funded clinical trial designed to compare the therapeutic benefits, safety, and tolerability of risperidone, olanzapine, and molindone in youths with early-onset schizophrenia spectrum disorders. The rationale, design, and methods of the Treatment of Early…
Fast Numerical Methods for the Design of Layered Photonic Structures with Rough Interfaces
NASA Technical Reports Server (NTRS)
Komarevskiy, Nikolay; Braginsky, Leonid; Shklover, Valery; Hafner, Christian; Lawson, John
2011-01-01
Modified boundary conditions (MBC) and a multilayer approach (MA) are proposed as fast and efficient numerical methods for the design of 1D photonic structures with rough interfaces. These methods are applicable for the structures, composed of materials with arbitrary permittivity tensor. MBC and MA are numerically validated on different types of interface roughness and permittivities of the constituent materials. The proposed methods can be combined with the 4x4 scattering matrix method as a field solver and an evolutionary strategy as an optimizer. The resulted optimization procedure is fast, accurate, numerically stable and can be used to design structures for various applications.
Development of direct-inverse 3-D methods for applied aerodynamic design and analysis
NASA Technical Reports Server (NTRS)
Carlson, Leland A.
1988-01-01
Several inverse methods have been compared and initial results indicate that differences in results are primarily due to coordinate systems and fuselage representations and not to design procedures. Further, results from a direct-inverse method that includes 3-D wing boundary layer effects, wake curvature, and wake displacement are presented. These results show that boundary layer displacements must be included in the design process for accurate results.
Novel observer design method for Lur'e differential inclusion systems
NASA Astrophysics Data System (ADS)
Huang, Jun; Gao, Yu; Yu, Lei
2016-07-01
This paper proposes a new method to design observers for Lur'e differential inclusion systems. The feature of this method is that the designed observers do not contain any set-valued functions. single-input-single-output (SISO) systems are considered firstly, then the results are extended to multiple-input-multiple-output (MIMO) systems. For MIMO systems, the form of reduced-order observers is also presented. Simulations are given to show these observers work well.
Compact lens design for LED chip array using supporting surface method
NASA Astrophysics Data System (ADS)
Zhang, Xiaohui; Chen, Chen
2015-10-01
As the low luminous flux of one single LED, LED chip array plays important effect on achieving high luminous flux in all kinds of applied field, such as automotive lighting, street lighting, sensing and imaging, etc. However, LED chip array is an extended source rather than a point source of conventional one single LED. Obviously, lens design for LED chip array will be reconsider and redesign to accommodate this difference. In recent years, as the development of illumination optics, some excellent optical design methods for extended source have been improved and suggested. When the design method for point source is adopt to design the LED chip array with high flux and high uniformity, the obtained Lens is so huge that the advantage of small LED chip is dissipated at this condition. The supporting surface method is effective and commonly used. However, it is not convergent when solving the refractor problem of designing point light source near field. Based on the property of Cartesian oval, a modified method is proposed and the convergence of the modified method is verified by Monte-Carlo ray trace. The number of the Cartesian oval and the size of the lens can be firmly under control during the design, while generally the ratio between the sizes of the lens and the chip is greater than 5. Based on the modified supporting surface method, a compact lens design method for extended light source is constructed. And the LED illumination lens is designed by this method and fabricated, and the simulation result shows that this LED illumination lens can achieve uniform illumination at target surface.
Multi-Reader ROC studies with Split-Plot Designs: A Comparison of Statistical Methods
Obuchowski, Nancy A.; Gallas, Brandon D.; Hillis, Stephen L.
2012-01-01
Rationale and Objectives Multi-reader imaging trials often use a factorial design, where study patients undergo testing with all imaging modalities and readers interpret the results of all tests for all patients. A drawback of the design is the large number of interpretations required of each reader. Split-plot designs have been proposed as an alternative, in which one or a subset of readers interprets all images of a sample of patients, while other readers interpret the images of other samples of patients. In this paper we compare three methods of analysis for the split-plot design. Materials and Methods Three statistical methods are presented: Obuchowski-Rockette method modified for the split-plot design, a newly proposed marginal-mean ANOVA approach, and an extension of the three-sample U-statistic method. A simulation study using the Roe-Metz model was performed to compare the type I error rate, power and confidence interval coverage of the three test statistics. Results The type I error rates for all three methods are close to the nominal level but tend to be slightly conservative. The statistical power is nearly identical for the three methods. The coverage of 95% CIs fall close to the nominal coverage for small and large sample sizes. Conclusions The split-plot MRMC study design can be statistically efficient compared with the factorial design, reducing the number of interpretations required per reader. Three methods of analysis, shown to have nominal type I error rate, similar power, and nominal CI coverage, are available for this study design. PMID:23122570
Csipke, Emese; Papoulias, Constantina; Vitoratou, Silia; Williams, Paul; Rose, Diana; Wykes, Til
2016-01-01
Abstract Background: Psychiatric ward design may make an important contribution to patient outcomes and well-being. However, research is hampered by an inability to assess its effects robustly. This paper reports on a study which deployed innovative methods to capture service user and staff perceptions of ward design. Method: User generated measures of the impact of ward design were developed and tested on four acute adult wards using participatory methodology. Additionally, inpatients took photographs to illustrate their experience of the space in two wards. Data were compared across wards. Results: Satisfactory reliability indices emerged based on both service user and staff responses. Black and minority ethnic (BME) service users and those with a psychosis spectrum diagnosis have more positive views of the ward layout and fixtures. Staff members have more positive views than service users, while priorities of staff and service users differ. Inpatient photographs prioritise hygiene, privacy and control and address symbolic aspects of the ward environment. Conclusions: Participatory and visual methodologies can provide robust tools for an evaluation of the impact of psychiatric ward design on users. PMID:26886239
Development of direct-inverse 3-D methods for applied transonic aerodynamic wing design and analysis
NASA Technical Reports Server (NTRS)
Carlson, Leland A.
1989-01-01
Progress in the direct-inverse wing design method in curvilinear coordinates has been made. This includes the remedying of a spanwise oscillation problem and the assessment of grid skewness, viscous interaction, and the initial airfoil section on the final design. It was found that, in response to the spanwise oscillation problem that designing at every other spanwise station produced the best results for the cases presented, a smoothly varying grid is especially needed for the accurate design at the wing tip, the boundary layer displacement thicknesses must be included in a successful wing design, the design of high and medium aspect ratio wings is possible with this code, and the final airfoil section designed is fairly independent of the initial section.
NASA Astrophysics Data System (ADS)
Zhao, Li-Ming; Yue, Gui-Kuan; Zhou, Yun-Song; Wang, Fu-He
2015-04-01
A new method, namely the nonlinear conjugate-gradient (NCG) method, is proposed to design nonlinear domains with a disordered distribution, in which an efficient broadband second harmonic generation can be achieved simultaneously with high conversion efficiency. It is demonstrated by numerical simulation that the NCG method has obvious advantages in realizing the optimal quasi-phase-matching, in comparison with the traditional simulated annealing method.
Accuracy of the domain method for the material derivative approach to shape design sensitivities
NASA Technical Reports Server (NTRS)
Yang, R. J.; Botkin, M. E.
1987-01-01
Numerical accuracy for the boundary and domain methods of the material derivative approach to shape design sensitivities is investigated through the use of mesh refinement. The results show that the domain method is generally more accurate than the boundary method, using the finite element technique. It is also shown that the domain method is equivalent, under certain assumptions, to the implicit differentiation approach not only theoretically but also numerically.
NASA Technical Reports Server (NTRS)
Martini, W. R.
1980-01-01
Four fully disclosed reference engines and five design methods are discussed. So far, the agreement between theory and experiment is about as good for the simpler calculation methods as it is for the more complicated methods, that is, within 20%. For the simpler methods, a one number adjustable constant can be used to reduce the error in predicting power output and efficiency over the entire operating map to less than 10%.
Automated divertor target design by adjoint shape sensitivity analysis and a one-shot method
Dekeyser, W.; Reiter, D.; Baelmans, M.
2014-12-01
As magnetic confinement fusion progresses towards the development of first reactor-scale devices, computational tokamak divertor design is a topic of high priority. Presently, edge plasma codes are used in a forward approach, where magnetic field and divertor geometry are manually adjusted to meet design requirements. Due to the complex edge plasma flows and large number of design variables, this method is computationally very demanding. On the other hand, efficient optimization-based design strategies have been developed in computational aerodynamics and fluid mechanics. Such an optimization approach to divertor target shape design is elaborated in the present paper. A general formulation of the design problems is given, and conditions characterizing the optimal designs are formulated. Using a continuous adjoint framework, design sensitivities can be computed at a cost of only two edge plasma simulations, independent of the number of design variables. Furthermore, by using a one-shot method the entire optimization problem can be solved at an equivalent cost of only a few forward simulations. The methodology is applied to target shape design for uniform power load, in simplified edge plasma geometry.
NASA Astrophysics Data System (ADS)
Kimball, Darby Suzan
branches of an event. This method of applying PRA techniques to criticality safety is demonstrated using the example of waste packages in an underground geologic repository during a volcanic event. It is concluded that the current design does not provide adequate subcritical assurance, and recommended that future design modifications focus on mitigating chemical degradation of fuel and metals.
Review on applications of 3D inverse design method for pump
NASA Astrophysics Data System (ADS)
Yin, Junlian; Wang, Dezhong
2014-05-01
The 3D inverse design method, which methodology is far superior to the conventional design method that based on geometrical description, is gradually applied in pump blade design. However, no complete description about the method is outlined. Also, there are no general rules available to set the two important input parameters, blade loading distribution and stacking condition. In this sense, the basic theory and the mechanism why the design method can suppress the formation of secondary flow are summarized. And also, several typical pump design cases with different specific speeds ranging from centrifugal pump to axial pump are surveyed. The results indicates that, for centrifugal pump and mixed pump or turbine, the ratio of blade loading on the hub to that on the shroud is more than unit in the fore part of the blade, whereas in the aft part, the ratio is decreased to satisfy the same wrap angle for hub and shroud. And the choice of blade loading type depends on the balancing of efficiency and cavitation. If the cavitation is more weighted, the better choice is aft-loaded, otherwise, the fore-loaded or mid-loaded is preferable to improve the efficiency. The stacking condition, which is an auxiliary to suppress the secondary flow, can have great effect on the jet-wake outflow and the operation range for pump. Ultimately, how to link the design method to modern optimization techniques is illustrated. With the know-how design methodology and the know-how systematic optimization approach, the application of optimization design is promising for engineering. This paper summarizes the 3D inverse design method systematically.
Simple method of designing centralized PI controllers for multivariable systems based on SSGM.
Dhanya Ram, V; Chidambaram, M
2015-05-01
A method is given to design multivariable PI/PID controllers for stable and unstable multivariable systems. The method needs only the steady state gain matrix (SSGM). The method is based on the static decoupler design followed by SISO PI/PID controllers design and combining the resulted decoupler and the diagonal PI(D) controllers as the centralized controllers. The result of the present method is shown to be equivalent to the empirical method proposed by Davison EJ. Multivariable tuning regulators: the feed-forward and robust control of general servo-mechanism problem. IEEE Trans Autom Control 1976;21:35-41. Three simulation examples are given. The performance of the controllers is compared with that of the reported centralized controller based on the multivariable transfer function matrix. PMID:25530257
Design Method of ILQ Robust Current Control System for Synchronous Reluctance Electrical Motors
NASA Astrophysics Data System (ADS)
Amano, Yoko; Takami, Hiroshi; Fujii, Takao
In this paper, a robust current control system for a synchronous reluctance electrical motor by an ILQ (Inverse Linear Quadratic) design method is proposed newly. First, for performing simultaneously decouple and large region linearization of an d-q axes system in the synchronous reluctance electrical motor using nonlinear state feedback, it is derived that a linear current-voltage state equation linearized model by the d-q axes decouple of the synchronous reluctance electrical motor. Next, according to the ILQ design method, an optimum solution and an optimal condition that achieve the robust current control system for the synchronous reluctance electrical motor are analytically derived, then the robust current control system can be designed. Finally, in practical experiments, we compare the proposed method with the PI (Proportional Integral) control method, the creativity and the usefulness of the proposed method are confirmed by experimental results.
A new traffic control design method for large networks with signalized intersections
NASA Technical Reports Server (NTRS)
Leininger, G. G.; Colony, D. C.; Seldner, K.
1979-01-01
The paper presents a traffic control design technique for application to large traffic networks with signalized intersections. It is shown that the design method adopts a macroscopic viewpoint to establish a new traffic modelling procedure in which vehicle platoons are subdivided into main stream queues and turning queues. Optimization of the signal splits minimizes queue lengths in the steady state condition and improves traffic flow conditions, from the viewpoint of the traveling public. Finally, an application of the design method to a traffic network with thirty-three signalized intersections is used to demonstrate the effectiveness of the proposed technique.
Practical use of three-dimensional inverse method for compressor blade design
Damle, S.; Dang, T.; Stringham, J.; Razinsky, E.
1999-04-01
The practical utility of a three-dimensional inverse viscous method is demonstrated by carrying out a design modification of a first-stage rotor in an industrial compressor. In this design modification study, the goal is to improve the efficiency of the original blade while retaining its overall aerodynamic, structural, and manufacturing characteristics. By employing a simple modification to the blade pressure loading distribution (which is the prescribed flow quantity in this inverse method), the modified blade geometry is predicted to perform better than the original design over a wide range of operating points, including an improvement in choke margin.
The 1995 forum on appropriate criteria and methods for seismic design of nuclear piping
Slagis, G.C.
1996-12-01
A record of the 1995 Forum on Appropriate Criteria and Methods for Seismic Design of Nuclear Piping is provided. The focus of the forum was the earthquake experience data base and whether the data base demonstrates that seismic inertia loads will not cause failure in ductile piping systems. This was a follow-up to the 1994 Forum when the use of earthquake experience data, including the recent Northridge earthquake, to justify a design-by-rule method was explored. Two possible topics for the next forum were identified--inspection after an earthquake and design for safe-shutdown earthquake only.
An application of performance goal based method for the design and evaluation of structures
Conrads, T.J.
1996-10-15
This paper describes an application of the U.S. Department of Energy`s (DOE) performance goal based method for the design and evaluation of structures, systems, and components (SSCS) at Fluor Daniel Hanford, Inc. (FDH). The philosophy on which DOE`s method is based has been employed to construct a graded approach to the minimum structural design and evaluation criteriz@ used at the DOE Hanford Site that complies with the DOE Order 54E;0.28, Natural Phenomena Hazards Mitigation. The FDH structural design and evaluation criteria applies to both nuclear and non-nuclear SSCs that are not covered by a reactor safety analysis report.
A moment-method design procedure for an array of EMC dipoles
NASA Astrophysics Data System (ADS)
Jackson, David R.; Dinbergs, Arturs E.; Long, Stuart A.
1990-05-01
A design procedure based on a moment-method analysis is given for an array of microstrip dipoles electromagnetically coupled (EMC) to microstrip transmission lines. One of the key features of the design procedure is that only one pair of EMC dipoles needs to be analyzed at a time in order to develop the necessary coupling coefficients. These coupling coefficients allow for the complete analysis or design of the array, accounting for interactions between all of the EMC line-dipole pairs. The EMC dipole arrays can also be designed so that the lengths and offsets of each dipole are the same, which simplifies the array construction.
An analytical sensitivity method for use in integrated aeroservoelastic aircraft design
NASA Technical Reports Server (NTRS)
Gilbert, Michael G.
1989-01-01
Interdisciplinary analysis capabilities have been developed for aeroservoelastic aircraft and large flexible spacecraft, but the requisite integrated design methods are only beginning to be developed. One integrated design method which has received attention is based on hierarchal problem decompositions, optimization, and design sensitivity analyses. This paper highlights a design sensitivity analysis method for Linear Quadratic Gaussian (LQG) optimal control laws, enabling the use of LQG techniques in the hierarchal design methodology. The LQG sensitivity analysis method calculates the change in the optimal control law and resulting controlled system responses due to changes in fixed design integration parameters using analytical sensitivity equations. Numerical results of an LQG design sensitivity analysis for a realistic aeroservoelastic aircraft example are presented. In this example, the sensitivity of the optimal control law and aircraft response for various parameters such as wing bending natural frequency is determined. The sensitivity results computed from the analytical expressions are used to estimate changes in response resulting from changes in the parameters. Comparisons of the estimates with exact calculated responses show they are reasonably accurate for + or - 15 percent changes in the parameters. Evaluation of the analytical expressions is computationally faster than equivalent finite difference calculations.
An analytical sensitivity method for use in integrated aeroservoelastic aircraft design
NASA Technical Reports Server (NTRS)
Gilbert, Michael G.
1989-01-01
Interdisciplinary analysis capabilities have been developed for aeroservoelastic aircraft and large flexible spacecraft, but the requisite integrated design methods are only beginning to be developed. One integrated design method which has received attention is based on hierarchal problem decompositions, optimization, and design sensitivity analyses. This paper highlights a design sensitivity analysis method for Linear Quadratic Gaussian (LQG) optimal control laws, enabling the use of LQG techniques in the hierarchal design methodology. The LQG sensitivity analysis method calculates the change in the optimal control law and resulting controlled system responses due to changes in fixed design integration parameters using analytical sensitivity equations. Numerical results of a LQG design sensitivity analysis for a realistic aeroservoelastic aircraft example are presented. In this example, the sensitivity of the optimal control law and aircraft response for various parameters such as wing bending natural frequency is determined. The sensitivity results computed from the analytical expressions are used to estimate changes in response resulting from changes in the parameters. Comparisons of the estimates with exact calculated responses show they are reasonably accurate for + or - 15 percent changes in the parameters. Evaluation of the analytical expressions is computationally faster than equivalent finite difference calculations.
Computational Fluid Dynamics-Based Design Optimization Method for Archimedes Screw Blood Pumps.
Yu, Hai; Janiga, Gábor; Thévenin, Dominique
2016-04-01
An optimization method suitable for improving the performance of Archimedes screw axial rotary blood pumps is described in the present article. In order to achieve a more robust design and to save computational resources, this method combines the advantages of the established pump design theory with modern computer-aided, computational fluid dynamics (CFD)-based design optimization (CFD-O) relying on evolutionary algorithms and computational fluid dynamics. The main purposes of this project are to: (i) integrate pump design theory within the already existing CFD-based optimization; (ii) demonstrate that the resulting procedure is suitable for optimizing an Archimedes screw blood pump in terms of efficiency. Results obtained in this study demonstrate that the developed tool is able to meet both objectives. Finally, the resulting level of hemolysis can be numerically assessed for the optimal design, as hemolysis is an issue of overwhelming importance for blood pumps. PMID:26526039
Application of direct inverse analogy method (DIVA) and viscous design optimization techniques
NASA Technical Reports Server (NTRS)
Greff, E.; Forbrich, D.; Schwarten, H.
1991-01-01
A direct-inverse approach to the transonic design problem was presented in its initial state at the First International Conference on Inverse Design Concepts and Optimization in Engineering Sciences (ICIDES-1). Further applications of the direct inverse analogy (DIVA) method to the design of airfoils and incremental wing improvements and experimental verification are reported. First results of a new viscous design code also from the residual correction type with semi-inverse boundary layer coupling are compared with DIVA which may enhance the accuracy of trailing edge design for highly loaded airfoils. Finally, the capabilities of an optimization routine coupled with the two viscous full potential solvers are investigated in comparison to the inverse method.
Design sensitivity analysis with Applicon IFAD using the adjoint variable method
NASA Technical Reports Server (NTRS)
Frederick, Marjorie C.; Choi, Kyung K.
1984-01-01
A numerical method is presented to implement structural design sensitivity analysis using the versatility and convenience of existing finite element structural analysis program and the theoretical foundation in structural design sensitivity analysis. Conventional design variables, such as thickness and cross-sectional areas, are considered. Structural performance functionals considered include compliance, displacement, and stress. It is shown that calculations can be carried out outside existing finite element codes, using postprocessing data only. That is, design sensitivity analysis software does not have to be imbedded in an existing finite element code. The finite element structural analysis program used in the implementation presented is IFAD. Feasibility of the method is shown through analysis of several problems, including built-up structures. Accurate design sensitivity results are obtained without the uncertainty of numerical accuracy associated with selection of a finite difference perturbation.
A frequency response model matching method for PID controller design for processes with dead-time.
Anwar, Md Nishat; Pan, Somnath
2015-03-01
In this paper, a PID controller design method for the integrating processes based on frequency response matching is presented. Two approaches are proposed for the controller design. In the first approach, a double feedback loop configuration is considered where the inner loop is designed with a stabilizing gain. In the outer loop, the parameters of the PID controller are obtained by frequency response matching between the closed-loop system with the PID controller and a reference model with desired specifications. In the second approach, the design is directly carried out considering a desired load-disturbance rejection model of the system. In both the approaches, two low frequency points are considered for matching the frequency response, which yield linear algebraic equations, solution of which gives the controller parameters. Several examples are taken from the literature to demonstrate the effectiveness and to compare with some well known design methods. PMID:25441218
NASA Technical Reports Server (NTRS)
Stahara, S. S.
1984-01-01
An investigation was carried out to complete the preliminary development of a combined perturbation/optimization procedure and associated computational code for designing optimized blade-to-blade profiles of turbomachinery blades. The overall purpose of the procedures developed is to provide demonstration of a rapid nonlinear perturbation method for minimizing the computational requirements associated with parametric design studies of turbomachinery flows. The method combines the multiple parameter nonlinear perturbation method, successfully developed in previous phases of this study, with the NASA TSONIC blade-to-blade turbomachinery flow solver, and the COPES-CONMIN optimization procedure into a user's code for designing optimized blade-to-blade surface profiles of turbomachinery blades. Results of several design applications and a documented version of the code together with a user's manual are provided.
Design method of planar vibration system for specified ratio of energy peaks
NASA Astrophysics Data System (ADS)
Kim, Jun Woo; Lee, Sungon; Choi, Yong Je
2015-05-01
The magnitudes of the resonant peaks should be considered in the design stage of any bandwidth-relevant applications to widen the working bandwidth. This paper presents a new design method for a planar vibration system that satisfies any desired ratio of peak magnitudes at target resonant frequencies. An important geometric property of a modal triangle formed from three vibration centers representing vibration modes is found. Utilizing the property, the analytical expressions for the vibration energy generated by external forces are derived in terms of the geometrical data of vibration centers. When any desired ratio of peak magnitudes is specified, the locations of the vibration centers are found from their analytical relations. The corresponding stiffness matrix can be determined and realized accordingly. The systematic design methods for direct- and base-excitation systems are developed, and one numerical example is presented to illustrate the proposed design method.
NASA Astrophysics Data System (ADS)
Tao, Shanshan; Dong, Sheng; Wang, Zhifeng; Jiang, Wensheng
2016-06-01
The maximum entropy distribution, which consists of various recognized theoretical distributions, is a better curve to estimate the design thickness of sea ice. Method of moment and empirical curve fitting method are common-used parameter estimation methods for maximum entropy distribution. In this study, we propose to use the particle swarm optimization method as a new parameter estimation method for the maximum entropy distribution, which has the advantage to avoid deviation introduced by simplifications made in other methods. We conducted a case study to fit the hindcasted thickness of the sea ice in the Liaodong Bay of Bohai Sea using these three parameter-estimation methods for the maximum entropy distribution. All methods implemented in this study pass the K-S tests at 0.05 significant level. In terms of the average sum of deviation squares, the empirical curve fitting method provides the best fit for the original data, while the method of moment provides the worst. Among all three methods, the particle swarm optimization method predicts the largest thickness of the sea ice for a same return period. As a result, we recommend using the particle swarm optimization method for the maximum entropy distribution for offshore structures mainly influenced by the sea ice in winter, but using the empirical curve fitting method to reduce the cost in the design of temporary and economic buildings.
Willoughby, Jessica Fitts; Myrick, Jessica Gall
2016-06-01
Research indicates that when people seek health information, they typically look for information about a specific symptom, preventive measure, disease, or treatment. It is unclear, however, whether general or disease-specific theoretical models best predict how people search for health information. We surveyed undergraduates (N = 963) at a large public southeastern university to examine health information seeking in two incongruent health contexts (sexual health and cancer) to test whether a general model would hold for specific topics that differed in their immediate personal relevance for the target population. We found that the planned risk information seeking model was statistically a good fit for the data. Yet multiple predicted paths were not supported in either data set. Certain variables, such as attitudes, norms, and affect, appear to be strong predictors of intentions to seek information across health contexts. Implications for theory building, research methodology, and applied work in health-related risk information seeking are discussed. PMID:27187057
Korakianitis, T. )
1993-04-01
The direct and inverse blade-design iterations for the selection of isolated airfoils and gas turbine blade cascades are enormously reduced if the initial blade shape has performance characteristics near the desirable ones. This paper presents the hierarchical development of three direct blade-design methods of increasing utility for generating two-dimensional blade shapes. The methods can be used to generate inputs to the direct- or inverse-blade-design sequences for subsonic or supersonic airfoils for compressors and turbines, or isolated airfoils. The first method specifies the airfoil shapes with analytical polynomials. It shows that continuous curvature and continuous slope of curvature are necessary conditions to minimize the possibility of flow separation, and to lead to improved blade designs. The second method specifies the airfoil shapes with parametric fourth-order polynomials, which result in continuous-slope-of-curvature airfoils, with smooth Mach number and pressure distributions. This method is time consuming. The third method specifies the airfoil shapes by using a mixture of analytical polynomials and mapping the airfoil surfaces from a desirable curvature distribution. The third method provides blade surfaces with desirable performance in very few direct-design iterations. In all methods the geometry near the leading edge is specified by a thickness distribution added to a construction line, which eliminates the leading edge overspeed and laminar-separation regions. The blade-design methods presented in this paper can be used to improve the aerodynamic and heat transfer performance of turbomachinery cascades, and they can result in high-performance airfoils in very few iterations.
A Modified Frequency Estimation Equating Method for the Common-Item Nonequivalent Groups Design
ERIC Educational Resources Information Center
Wang, Tianyou; Brennan, Robert L.
2009-01-01
Frequency estimation, also called poststratification, is an equating method used under the common-item nonequivalent groups design. A modified frequency estimation method is proposed here, based on altering one of the traditional assumptions in frequency estimation in order to correct for equating bias. A simulation study was carried out to…
Under Part 53 of Title 40 of the Code of Federal Regulations (40 CFR Part 53), the U.S. Environmental Protection Agency designates specific ambient monitoring methods and analyzers as reference or equivalent methods acceptable for use in National Air Monitoring Stations (NAMS), S...