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A Critical Review of the Observational MethodSpross, Johan January 2014 (has links)
Building a sustainable structure in soil or rock that satisfies all predefined technical requirements implies choosing a rational and effective construction method. An important aspect is how the performance of the structure is verified. For cases when the geotechnical behaviour is hard to predict, the existing design code for geotechnical structures, Eurocode 7, suggests the so-called “observational method” to verify that the performance is acceptable. The basic principle of the method is to accept predefined changes in the design during construction, in order to accommodate the actual ground conditions, if the current design is found unsuitable. Even though this in theory should ensure an effective design solution, formal application of the observational method is rare. It is therefore not clear which prerequisites and circumstances that must be present for the observational method to be applicable and be the more suitable method. This licentiate thesis gives a critical review of the observational method, based on, and therefore limited by, the outcome of the performed case studies. The aim is to identify and highlight the crucial aspects that make the observational method difficult to apply, thereby providing a basis for research towards a more applicable definition of the method. The main topics of discussion are (1) the apparent contradiction between the preference for advanced probabilistic calculation methods to solve complex design problems and sound, qualitative engineering judgement, (2) the limitations of measurement data in assessing the safety of a structure, (3) the fact that currently, no safety margin is required for the completed structure when the observational method is applied, and (4) the rigidity of the current definition of the observational method and the implications of deviations from its principles. Based on the review, it is argued that the observational method can be improved by linking it to a probabilistic framework. To be applicable, the method should be supported by guidelines that explain and exemplify how to make the best use of it. The engineering judgement is however not lost; no matter how elaborate probabilistic methods are used, sound judgement is still needed to define the problem correctly. How to define such a probabilistic framework is an urgent topic for future research, because this also addresses the concerns regarding safety that is raised in the other topics of discussion. / För att i berg eller jord kunna konstruera en anläggning, som uppfyller satta tekniska krav, krävs det att man väljer en rationell och effektiv konstruktionsmetod. En viktig aspekt i detta val är hur man verifierar konstruktionens funktion avseende exempelvis bärförmåga eller stadga. För fall när konstruktionens beteende svårt att förutsäga, erbjuder gällande standard (Eurokod 7) den så kallade observationsmetoden. Denna metod tillåter i förväg förberedda förändringar i designen under konstruktionstiden, om observationer av konstruktionens beteende indikerar att så behövs. På så vis anpassas konstruktionen till de faktiska förhållandena i marken. Trots att detta tillvägagångssätt i teorin borde ge en rationell design, används metoden sällan. Det råder därför oklarheter om vilka förutsättningar och omständigheter som krävs för att observationsmetoden ska kunna användas och dessutom utgöra den bästa lösningen. I denna licentiatuppsats granskas observationsmetoden och dess användbarhet. Målet med licentiatuppsatsen är att belysa de aspekter som kan utgöra svårigheter när observationsmetoden används. Dessa identifierades under arbetet med några fallstudier. Licentiatuppsatsen ger därmed en utgångspunkt för fortsatt forskning för att ta fram en mer användbar definition av observationsmetoden. De viktigaste aspekterna som diskuteras i uppsatsen är (1) den skenbara motsatsen mellan användandet av sannolikhetsbaserade beräkningsmetoder för att lösa komplexa dimensioneringsfrågor och kvalitativa ingenjörsmässiga bedömningar, (2) de begränsningar som finns när man använder mätdata för att utvärdera konstruktioners säkerhet, (3) att det för tillfället saknas krav på säkerhetsmarginal mot brott för konstruktioner som byggts med observationsmetoden, och (4) vad svårigheten att uppfylla Eurokodens strikta definition innebär för metodens användbarhet. Utifrån resultatet av granskningen dras slutsatsen att observationsmetoden kan förbättras genom att ge den ett sannolikhetsbaserat ramverk. För att förenkla användningen bör riktlinjer och anvisningar utformas. Även om metoden utvecklas mot en högre grad av beräkningskomplexitet, kommer ingenjörsmässiga bedömningar också framgent att vara viktiga, eftersom en avgörande aspekt är hur problemställningen formuleras. Med ett sannolikhetsbaserat ramverk ökar möjligheten att lösa de frågeställningar kring säkerhet som också diskuteras i uppsatsen. / <p>QC 20140415</p>
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Assessing the Reliability of Scores Produced by the Substance Abuse Subtle Screening InventoryMiller, Christopher S., Woodson, Joshua, Howell, Ryan T., Shields, Alan L. 04 December 2009 (has links)
The Substance Abuse Subtle Screening Inventory (SASSI) is a 10 scale indirect screening instrument used to detect substance use disorders. The current meta-analytic study described reliability reporting practices across 48 studies involving the SASSI. Reliability generalization methods were then employed to evaluate typical score reliability for the screening measure. Results showed approximately 73 of studies did not report reliability estimates. Analysis of data from the remaining studies revealed adequate reliability for the total scale (α .87) and face valid scales (FVA α .88 and FVOD α .92), but substantially lower reliability estimates for the indirect scales (range of α .23.65). The study's findings underscore the need for improved reliability reporting for the SASSI and suggest cautious use of the measure, especially its indirect scales, as an indicator of problematic substance use/abuse in clinical settings.
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Substance Use Scales of the Minnesota Multiphasic Personality Inventory: An Exploration of Score Reliability via Meta-AnalysisMiller, Christopher S., Shields, Alan L., Campfield, Delia, Wallace, Kim A., Weiss, Roger D. 01 January 2007 (has links)
Three drug and alcohol use screening scales are embedded within the Minnesota Multiphasic Personality Inventory-2: the MacAndrew Alcoholism Scale (MAC) and its revised version (MAC-R), the Addiction Acknowledgement Scale (AAS), and the Addiction Potential Scale (APS). The current study evaluated the reliability reporting practices among 210 studies administering the MAC/MAC-R, APS, and/or AAS. Furthermore, reliability generalization methods were used to characterize the previously reported reliability estimates associated with each instrument. The vast majority of studies (90.6%) did not provide measurement reliability data, suggesting a need for improved psychometric reporting. Data from the remaining studies yielded mean and median score reliability estimates below.70 for each of the identified measures. Although limited in some instances by sample size constraints, results suggest that these instruments tend not to produce scores with acceptable levels of reliability for most research or clinical situations.
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Assessment of Pseudo-Continuous Arterial Spin Labeling (pCASL) Inter-Session Reliability in the Quantification of Cerebral PerfusionAwad, Mohammad Ahmad 17 June 2019 (has links)
No description available.
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Reliability Analysis and Updating with Meta-models: An Adaptive Kriging-Based ApproachWang, Zeyu January 2019 (has links)
No description available.
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Can reliability centered maintenance foster asset management? : A case study at the process-oriented steel company OutokumpuJonsson, Niklas January 2022 (has links)
No description available.
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A Content Analysis of Reliability in Advertising Content Analysis Studies.Wang, Weize 17 December 2011 (has links) (PDF)
Content analysis is a systematic research method for examining symbolical content in communication by recording or transcribing these messages into categories. Reliability is one of the most distinctive attributes of content analysis methodology comparing to other techniques in communication. A content analysis was conducted by analyzing the method sections of published journal articles in Communication Abstracts from January 2006 through January 2011 by searching "advertising" and "content analysis". Results suggested that television is still the most focused medium in advertising content analysis research. Most of the content analysis studies employed 2 coders for coding reliability assessment data and final data. Moreover, content analysis researchers had improved in reporting reliability and reliability coefficients. However, there was a low percentage of studies that reported specific reliability for each variable as well as the lowest acceptable level for the reliability coefficients.
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Using Duplication with Compare for On-line Error Detection in FPGA-based DesignsMcMurtrey, Daniel L. 06 December 2006 (has links) (PDF)
Space destined FPGA-based systems must employ redundancy techniques to account for the effects of upsets caused by radiated environments. Error detection techniques can be used to alert external systems to the presence of these upsets. Readback with compare is an error detection technique commonly employed in FPGA-based designs. This work introduces duplication with compare (DWC) as an automated on-line error detection technique that can be used as an alternative to readback with compare. This work also introduces a set of metrics that is used to quantify the effectiveness and coverage of this error detection technique. A tool is presented that automatically inserts duplication with compare into a user's design. Duplication with compare is shown to correctly detect over 99.9% of errors caused by configuration upsets at a hardware cost of approximately 2X. System designers can apply duplication with compare to designs using this tool to increase the reliability and availability of their systems while minimizing resource usage and power.
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Exploring Travel Time Reliability Using Bluetooth Data Collection: A Case Study in San Luis Obispo, CaliforniaPurser, Krista 01 June 2016 (has links) (PDF)
Bluetooth technology applications have improved travel time data collection efforts and allowed for collection of large data sets at a low cost per data unit. Mean travel times between pairs of points are available, but the primary value of this technique is the availability of the entire distribution of travel times throughout multiple days and time periods, allowing for a greater understanding of travel time variations and reliability. The use of these data for transportation planning, engineering and operations continues to expand. Previous applications of similar data sources have included travel demand and simulation model validation, work zone traffic patterns, transit ridership and reliability, pedestrian movement patterns, and before-after studies of transportation improvements. This thesis investigates the collection and analysis of Bluetooth-enabled travel time data along a multimodal arterial corridor in San Luis Obispo, California. Five BlueMAC devices collected multimodal travel time data in January and February 2016 along Los Osos Valley Road. These datasets were used to identify and process known sources of error such as occasions where vehicles using the roadway turn off and make an intermediate stop and multiple reads from the same vehicle; quantify travel time performance and reliability along arterial streets; and compare transit, bicycle, and pedestrian facility performance. Additionally, a travel time model was estimated based on segment characteristics and Bluetooth data to estimate average speeds and travel time distributions.
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Probabilistic Design Optimization of Built-Up Aircraft Structures with ApplicationXie, Qiulin 13 December 2003 (has links)
This thesis discusses a methodology for probabilistic design optimization of aircraft structures subject to a multidisciplinary set of requirements originating from the desire to minimize structural weight while fulfilling the demands for quality, safety, producibility, and affordability. With this design methodology as the framework, a software is developed, which is capable of performing design optimization of metallic built-up beam structures where the material properties, external load, as well as the structural dimensions are treated as probabilistic random variables. The structural and failure analyses are based on analytical and semi-empirical methods whereas the component reliability analysis is based on advanced first-order second moment method. Metrics-based analytical models are used for the manufacturability analysis of individual parts with the total manufacturing cost estimated using models derived from the manufacturing cost / design guide developed by the Battelle¡¯s Columbus Laboratories. The resulting optimization problem is solved using the method of sequential quadratic programming. A wing spar design optimization problem is used as a demonstrative example including a comparison between non-buckling and buckling web design concepts. A sensitivity analysis is performed and the optimization results are used to highlight the tradeoffs among weight, reliability, and manufacturing cost.
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