Diversity for NPP I&C Systems Safety and Cyber Security

Author(s):  
Ievgen Babeshko ◽  
Vyacheslav Duzhiy ◽  
Oleg Illiashenko ◽  
Alexander Siora ◽  
Vladimir Sklyar ◽  
...  

This chapter presents a cost-effective approach to selection of the most diverse NPP Reactor Trip System (RTS) under uncertainty. The selection of a pair of primary and secondary RTS is named a diversity strategy. All possible strategies are evaluated on an ordinal scale with linguistic values provided by experts. These values express the expert's degree of confidence that evaluated variants of secondary RTS are different from primary RTS. All diversity strategies are evaluated on a set of linguistic diversity criteria, which are included in a corresponding diversity attribute. The generic fuzzy diversity score is an aggregation of the linguistic values provided by the experts to obtain a collective assessment of the secondary RTS's similarity (difference) with a primary one. This most rational diversity strategy is found during the exploitation stage, taking into consideration the fuzzy diversity score and cost of each strategy.

Author(s):  
Alexander Siora ◽  
Vladimir Sklyar ◽  
Vyacheslav Kharchenko ◽  
Eugene Brezhnev

To protect safety-critical systems from common-cause failures that can lead to potentially dangerous outcomes, special methods are applied, including multi-version technologies operating at different levels of diversity. A model representing different diversity types during the development of safety-critical systems is suggested. The model addresses diversity types that are the most expedient in providing required safety. The diversity of complex electronic components (FPGA, etc.), printed circuit boards, manufacturers, specification languages, design, and program languages, etc. are considered. The challenges addressed are related to factors of scale and dependencies among diversity types, since not all combinations of used diversity are feasible. Taking these dependencies into consideration, the model simplifies the choice of diversity options. This chapter presents a cost effective approach to selection of the most diverse NPP Reactor Trip System (RTS) under uncertainty. The selection of a pair of primary and secondary RTS is named a diversity strategy. All possible strategies are evaluated on an ordinal scale with linguistic values provided by experts. These values express the expert’s degree of confidence that evaluated variants of secondary RTS are different from primary. All diversity strategies are evaluated on a set of linguistic diversity criteria, which are included into a corresponding diversity attribute. The generic fuzzy diversity score is an aggregation of the linguistic values provided by the experts to obtain a collective assessment of the secondary RTS’s similarity (difference) with a primary one. This rational diversity strategy is found during the exploitation stage, taking into consideration the fuzzy diversity score and cost.


2017 ◽  
pp. 535-592
Author(s):  
Alexander Siora ◽  
Vladimir Sklyar ◽  
Vyacheslav Kharchenko ◽  
Eugene Brezhnev

To protect safety-critical systems from common-cause failures that can lead to potentially dangerous outcomes, special methods are applied, including multi-version technologies operating at different levels of diversity. A model representing different diversity types during the development of safety-critical systems is suggested. The model addresses diversity types that are the most expedient in providing required safety. The diversity of complex electronic components (FPGA, etc.), printed circuit boards, manufacturers, specification languages, design, and program languages, etc. are considered. The challenges addressed are related to factors of scale and dependencies among diversity types, since not all combinations of used diversity are feasible. Taking these dependencies into consideration, the model simplifies the choice of diversity options. This chapter presents a cost effective approach to selection of the most diverse NPP Reactor Trip System (RTS) under uncertainty. The selection of a pair of primary and secondary RTS is named a diversity strategy. All possible strategies are evaluated on an ordinal scale with linguistic values provided by experts. These values express the expert's degree of confidence that evaluated variants of secondary RTS are different from primary. All diversity strategies are evaluated on a set of linguistic diversity criteria, which are included into a corresponding diversity attribute. The generic fuzzy diversity score is an aggregation of the linguistic values provided by the experts to obtain a collective assessment of the secondary RTS's similarity (difference) with a primary one. This rational diversity strategy is found during the exploitation stage, taking into consideration the fuzzy diversity score and cost.


Author(s):  
Anna C. Thornton

Abstract Quality has been a rallying call in the design and manufacturing world for the last two decades. One way to improve quality is to reduce the impact of manufacturing variation. Variation risk mitigation is challenging especially when a product has multiple quality characteristics and complex production and assembly. It is common wisdom that companies should identify and mitigate the risk associated with variation throughout the design process. As yield problems are identified, they should be mitigated using the most cost effective approach. One approach to variation risk mitigation is variation reduction (VR). VR targets reduction of variation introduced by existing manufacturing processes using tools such as Design of Experiments (DOE) and robust design. Many companies have specialized groups that specialize in these methods. VR teams have the role of improving manufacturing performance; however, these teams are limited in their resources. In addition, no tools exist to quantitatively determine where a VR team’s efforts are most effectively deployed. This paper provides a mathematical and optimization model to best allocate VR resources in a complex product.


2021 ◽  
Vol 13 ◽  
pp. 1759720X2110403
Author(s):  
Jean-Charles Rousseau ◽  
Roland Chapurlat ◽  
Patrick Garnero

In recent years, markers research has focused on the structural components of cartilage matrix. Specifically, a second generation of degradation markers has been developed against type II collagen neoepitopes generated by specific enzymes. A particular effort has been made to measure the degradation of minor collagens III and X of the cartilage matrix. However, because clinical data, including longitudinal controlled studies, are very scarce, it remains unclear whether they will be useful as an alternative to or in combination with current more established collagen biological markers to assess patients with osteoarthritis (OA). In addition, new approaches using high-throughput technologies allowed to detect new types of markers and improve the knowledge about the metabolic changes linked to OA. The relative advances coming from phenotype research are a first attempt to classify the heterogeneity of OA, and several markers could improve the phenotype characterization. These phenotypes could improve the selection of patients in clinical trials limiting the size of the studies by selecting patients with OA characteristics corresponding to the metabolic pathway targeted by the molecules evaluated. In addition, the inclusion of rapid progressors only in clinical trials would facilitate the demonstration of efficacy of the investigative drug to reduce joint degradation. The combination of selective biochemical markers appears as a promising and cost-effective approach to fulfill this unmet clinical need. Among the various potential roles of biomarkers in OA, their ability to monitor drug efficacy is probably one of the most important, in association with clinical and imaging parameters. Biochemical markers have the unique property to detect changes in joint tissue metabolism within a few weeks.


Author(s):  
Dan Salas ◽  
Aaron Steber

Maintenance of existing rights-of-way often involve dealing with exposed pipelines near stream crossings. Streams often shift over time. This adjustment can lead to erosion of the streambed and streambanks, exposing pipelines or other infrastructure to threats such as hydraulic pressure, buoyancy, debris collisions, or pipe vibration and fatigue. Under these conditions, managers can be faced with relocating the pipe, performing localized streambank stabilization, or employing stream restoration techniques to provide long-term protection. When localized stabilization is the preferred approach, selection of techniques is often determined by what will protect the pipeline without consideration of the stream context surrounding it. However, due to site conditions, manager preferences, and regulatory considerations, techniques from the disciplines of stream restoration and habitat enhancement can provide cost-effective alternatives to traditional hard-armoring by concrete or stone depending on the site context. Using past experience and a series of decision analysis tools, it was determined that geomorphic context should be factored as a foremost consideration when evaluating the most stable and cost effective approach to correcting exposed pipelines. One of the most critical factors in assessing the feasibility of stabilization options is the height and orientation of exposed pipes relative to the stream’s bankfull elevation.


2020 ◽  
Vol 41 (1) ◽  
pp. 89-99
Author(s):  
Aureliano Paolo Finch ◽  
John Brazier ◽  
Clara Mukuria

Background Generic preference-based measures (GPBMs) such as the EQ-5D are valid across many conditions, but in some cases, “bolting on” additional dimensions may improve validity. The selection of “bolt-ons” has been based on the psychometric impact of individual dimensions, but preferences provide another important way to select them. This study aims to test the potential of using pairwise choices to inform the selection of bolt-ons for the EQ-5D-5L. Methods General population preferences were collected using an online survey of 1040 UK residents. Three EQ-5D-5L health state pairs were selected based on pairs that had a 50:50 split in respondent preferences from a previous pairwise survey. Participants were presented with pairwise choices of EQ-5D-5L health states without and with bolt-ons of hearing, sleep, cognition, energy, and relationships, each added individually. Logistic models were used to assess the impact of bolt-ons, as well as bolt-ons at different severity levels, on the log odds of responders choosing between health states. Results Preferences varied according to the bolt-ons and their severity level (only levels 1, 3, and 5 were used). Additions of bolt-ons at level 1 generally resulted in nonstatistically significant differences while additions of bolt-ons at level 3 and level 5 produced a negative and statistically significant impact on preferences for the health state with the bolt-on. At level 5, hearing had the largest impact, followed by cognition, relationships, energy, and sleep. At level 3, cognition produced the largest impact, followed by hearing and sleep with similar impacts, energy, and relationships. This ordering offers information for bolt-on selection, with hearing and cognition appearing as the most important. The weight placed on the different health problems is not constant across severity levels between bolt-ons. Conclusions Pairwise choices provide a cost-effective approach of generating information on preferences to support bolt-on selection.


1985 ◽  
Vol 24 (03) ◽  
pp. 163-165 ◽  
Author(s):  
K. John

SummaryAs many bibliographic services in medicine are offered, literature searches in eight databases at DIMDI were performed to find out which database is most important in medicine. The distribution of publications from members of the medical faculty of Frankfurt University was examined. No save prediction is possible as to which database will yield most articles. Overlapping from different databases is often rather low. The selection of an appropriate database mix for sufficient recall and in a cost-effective manner.is a task for an experienced searcher.


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