• Title/Summary/Keyword: Uncertain systems

Search Result 1,027, Processing Time 0.024 seconds

Normalizing interval data and their use in AHP (구간데이터 정규화와 계층적 분석과정에의 활용)

  • Kim, Eun Young;Ahn, Byeong Seok
    • Journal of Intelligence and Information Systems
    • /
    • v.22 no.2
    • /
    • pp.1-11
    • /
    • 2016
  • Entani and Tanaka (2007) presented a new approach for obtaining interval evaluations suitable for handling uncertain data. Above all, their approach is characterized by the normalization of interval data and thus the elimination of redundant bounds. Further, interval global weights in AHP are derived by using such normalized interval data. In this paper, we present a heuristic method for finding extreme points of interval data, which basically extends the method by Entani and Tanaka (2007), and also helps to obtain normalized interval data. In the second part of this paper, we show that the solutions to the linear program for interval global weights can be obtained by a simple inspection. In the meantime, the absolute dominance proposed by the authors is extended to pairwise dominance which makes it possible to identify at least more dominated alternatives under the same information.

Optimization of Early-phase Ship Design using Set-Based Design and Genetic Algorithm (집합기반설계와 유전자알고리즘을 이용한 초기단계 함정설계 최적화)

  • Park, Jin-Won
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.20 no.10
    • /
    • pp.486-492
    • /
    • 2019
  • The system-based approach is needed to select an optimal mix of weapon systems and ship platform among a variety of design alternatives with the uncertainties of the initial required operational capability. In the early-phase design, which included a feasibility study and concept design, it is possible to cause problems when a review of the operational concept, database development, and systematic design are not done, thereby producing uncertain and unstable requirements. To select the best solution without trial-and-error, the U.S. navy has applied the set-based method for the early-phase design of a new ship-to-shore connector. The ship synthesis model plays an important role in applying the set-based method, but only a few countries possess this model and have prohibited this model from being transferred to other countries. This paper suggests a set-based method using a genetic algorithm and decision-making theory through benchmarking existing ship data. The algorithm was verified using the DDG-51 class ship synthesis model to optimize the weapon system design, which has been released for research purposes.

VHTR Construction Ripple Effect Analysis Using Inter-Industry Tables (산업연관분석을 통한 초고온가스로 건설 파급효과 분석)

  • Lee, Tae-Hoon;Lee, Ki-Young
    • Journal of Korean Society of Industrial and Systems Engineering
    • /
    • v.38 no.4
    • /
    • pp.39-44
    • /
    • 2015
  • The VHTR (Very High Temperature gas-cooled nuclear Reactor) has been considered as a major heat source and the most safe generation IV type reactor for mass hydrogen production to prepare for the hydrogen economy era. The VHTR satisfies goals for the GIF (Generation IV International Forum) policy such as sustainablility, economics, reliability and proliferation resistance and physical protection, and safety. As a part of a VHTR economic analysis, we have studied the VHTR construction cost and operation and maintenance cost. However, it is somewhat difficult to expect the ripple effect on the whole industry due to the lack of information about Inter-industries relationship. In many case, the ripple effect are based on experts' knowledge or uncertain qualitative assumptions. As a result, we propose quantitative analysis techniques for ripple effects such as the production inducement effect, added value inducement effect, and employment inducement effect for VHTR 600MWt${\times}$4 modules construction and operation ripple effect based on NOAK (Nth Of A Kind). Because inducement effect values have been published annually, we predict inducement effect's relation function and estimated values including production inducement effect value, added value inducement effect value, and employment inducement effect value using time series and estimated values are verified with published inducement effects' value. This paper presents a new method for the ripple effect and preliminary ripple effect consequence using a time series analysis and inter-industry table. This ripple effect analysis techniques can be applied to effect expectation analysis as well as other type reactor's ripple effect analysis including VHTR for process heat.

Manual model updating of highway bridges under operational condition

  • Altunisik, Ahmet C.;Bayraktar, Alemdar
    • Smart Structures and Systems
    • /
    • v.19 no.1
    • /
    • pp.39-46
    • /
    • 2017
  • Finite element model updating is very effective procedure to determine the uncertainty parameters in structural model and minimize the differences between experimentally and numerically identified dynamic characteristics. This procedure can be practiced with manual and automatic model updating procedures. The manual model updating involves manual changes of geometry and analyses parameters by trial and error, guided by engineering judgement. Besides, the automated updating is performed by constructing a series of loops based on optimization procedures. This paper addresses the ambient vibration based finite element model updating of long span reinforced concrete highway bridges using manual model updating procedure. Birecik Highway Bridge located on the $81^{st}km$ of Şanliurfa-Gaziantep state highway over Firat River in Turkey is selected as a case study. The structural carrier system of the bridge consists of two main parts: Arch and Beam Compartments. In this part of the paper, the arch compartment is investigated. Three dimensional finite element model of the arch compartment of the bridge is constructed using SAP2000 software to determine the dynamic characteristics, numerically. Operational Modal Analysis method is used to extract dynamic characteristics using Enhanced Frequency Domain Decomposition method. Numerically and experimentally identified dynamic characteristics are compared with each other and finite element model of the arch compartment of the bridge is updated manually by changing some uncertain parameters such as section properties, damages, boundary conditions and material properties to reduce the difference between the results. It is demonstrated that the ambient vibration measurements are enough to identify the most significant modes of long span highway bridges. Maximum differences between the natural frequencies are reduced averagely from %49.1 to %0.6 by model updating. Also, a good harmony is found between mode shapes after finite element model updating.

Clinical spectrum and short-term outcomes of multisystem inflammatory syndrome in children in a south Indian hospital

  • Balagurunathan, Muruganantham;Natarajan, Thrilok;Karthikeyan, Jothilakshmi;Palanisamy, Venkateshwaran
    • Clinical and Experimental Pediatrics
    • /
    • v.64 no.10
    • /
    • pp.531-537
    • /
    • 2021
  • Background: Multisystem inflammatory syndrome in children (MIS-C) is a new hyperinflammatory variant that evolved during the coronavirus disease 2019 pandemic. Although the precise pathophysiology of MIS-C is uncertain, it is thought to be due to immune dysregulation occurring after recovery from acute infection. Purpose: Our study aimed to analyze the clinical spectrum, laboratory parameters, imaging characteristics, treatment strategies, and short-term outcomes of children with a diagnosis of MIS-C. Methods: This retrospective and prospective observational study included children less than 16 years of age who were admitted to the pediatric unit of a tertiary care teaching hospital in south India between August 2020 to January 2021 with a diagnosis of MIS-C according to World Health Organization criteria. Results: Twenty-one children were included in the analysis; all had fever with variable combinations of other symptoms. The mean age was 6.9 years; 71.4% were male. Gastrointestinal (80.9%) and cardiovascular (80.9%) systems were the most commonly affected. The majority of children had elevated inflammatory markers, and 16 (76.2%) had echocardiographic abnormalities mimicking Kawasaki disease. Eleven children (52.4%) required intensive care admission, 3 (14.3%) required supplemental oxygen, and 4 (19%) required inotropes. Nine (42.9%) were treated with intravenous immunoglobulin alone, 6 (28.6%) with steroids alone, and 3 (14.3%) with steroids and immunoglobulin. The median hospital stay was 6 days; there were no fatalities. Overweight/obesity, elevated ferritin, and mucocutaneous involvement were significantly associated with a prolonged hospital stay (≥7 days). Sixteen children (76.2%) were followed up till now and all of them had no clinical concerns. Conclusion: MIS-C is an emerging disease with variable presentation. A high index of suspicion is necessary for its early identification and appropriate management. Further research is essential for developing optimal treatment strategies.

Prospective evaluation of the clinical utility of whole-exome sequencing using buccal swabbing for undiagnosed rare diseases

  • Chong Kun Cheon;Yong Beom Shin;Soo-Yeon Kim;Go Hun Seo;Hane Lee;Changwon Keum;Seung Hwan Oh
    • Journal of Genetic Medicine
    • /
    • v.19 no.2
    • /
    • pp.76-84
    • /
    • 2022
  • Purpose: Whole-exome sequencing (WES) has been a useful tool for novel gene discovery of various disease categories, further increasing the diagnostic yield. This study aimed to investigate the clinical utility of WES prospectively in undiagnosed genetic diseases. Materials and Methods: WES tests were performed on 110 patients (age range, 0-28 years) with suspected rare genetic diseases. WES tests were performed at a single reference laboratory and the variants reported were reviewed by clinical geneticists, pediatricians, neurologists, and laboratory physicians. Results: The patients' symptoms varied with abnormalities in the head or neck, including facial dysmorphism, being the most common, identified in 85.4% of patients, followed by abnormalities in the nervous system (83.6%). The average number of systems manifesting phenotypic abnormalities per patient was 3.9±1.7. The age at presentation was 2.1±2.7 years old (range, 0-15 years), and the age at WES testing was 6.7±5.3 years (range, 0-28 years). In total, WES test reported 100 pathogenic/likely pathogenic variants or variants of uncertain significance for 79 out of 110 probands (71.8%). Of the 79 patients with positive or inconclusive calls, 55 (50.0%) patients were determined to have good genotype-phenotype correlations after careful review. Further clinical reassessment and family member testing determined 45 (40.9%) patients to have been identified with a molecular diagnosis. Conclusion: This study showed a 40.9% diagnostic yield for WES test for a heterogeneous patient cohort with suspected rare genetic diseases. WES could be the feasible genetic test modality to overcome the diversity and complexity of rare disease diagnostics.

A Simulation-based Optimization for Scheduling in a Fab: Comparative Study on Different Sampling Methods (시뮬레이션 기반 반도체 포토공정 스케줄링을 위한 샘플링 대안 비교)

  • Hyunjung Yoon;Gwanguk Han;Bonggwon Kang;Soondo Hong
    • Journal of the Korea Society for Simulation
    • /
    • v.32 no.3
    • /
    • pp.67-74
    • /
    • 2023
  • A semiconductor fabrication facility(FAB) is one of the most capital-intensive and large-scale manufacturing systems which operate under complex and uncertain constraints through hundreds of fabrication steps. To improve fab performance with intuitive scheduling, practitioners have used weighted-sum scheduling. Since the determination of weights in the scheduling significantly affects fab performance, they often rely on simulation-based decision making for obtaining optimal weights. However, a large-scale and high-fidelity simulation generally is time-intensive to evaluate with an exhaustive search. In this study, we investigated three sampling methods (i.e., Optimal latin hypercube sampling(OLHS), Genetic algorithm(GA), and Decision tree based sequential search(DSS)) for the optimization. Our simulation experiments demonstrate that: (1) three methods outperform greedy heuristics in performance metrics; (2) GA and DSS can be promising tools to accelerate the decision-making process.

Malignancy Risk Stratification of Thyroid Nodules with Macrocalcification and Rim Calcification Based on Ultrasound Patterns

  • Hwa Seon Shin;Dong Gyu Na;Wooyul Paik;So Jin Yoon;Hye Yun Gwon;Byeong-Joo Noh;Won Jun Kim
    • Korean Journal of Radiology
    • /
    • v.22 no.4
    • /
    • pp.663-671
    • /
    • 2021
  • Objective: To determine the association of macrocalcification and rim calcification with malignancy and to stratify the malignancy risk of thyroid nodules with macrocalcification and rim calcification based on ultrasound (US) patterns. Materials and Methods: The study included a total of 3603 consecutive nodules (≥ 1 cm) with final diagnoses. The associations of macrocalcification and rim calcification with malignancy and malignancy risk of the nodules were assessed overall and in subgroups based on the US patterns of the nodules. The malignancy risk of the thyroid nodules was categorized as high (> 50%), intermediate (upper-intermediate: > 30%, ≤ 50%; lower-intermediate: > 10%, ≤ 30%), and low (≤ 10%). Results: Macrocalcification was independently associated with malignancy in all nodules and solid hypoechoic (SH) nodules (p < 0.001). Rim calcification was not associated with malignancy in all nodules (p = 0.802); however, it was independently associated with malignancy in partially cystic or isoechoic and hyperechoic (PCIH) nodules (p = 0.010). The malignancy risks of nodules with macrocalcification were classified as upper-intermediate and high in SH nodules, and as low and lower-intermediate in PCIH nodules based on suspicious US features. The malignancy risks of nodules with rim calcification were stratified as low and lower-intermediate based on suspicious US features. Conclusion: Macrocalcification increased the malignancy risk in all and SH nodules with or without suspicious US features, with low to high malignancy risks depending on the US patterns. Rim calcification increased the malignancy risk in PCIH nodules, with low and lower-intermediate malignancy risks based on suspicious US features. However, the role of rim calcification in risk stratification of thyroid nodules remains uncertain.

Design of Rural Business Model to Prevent Reservoir Flood (저수지 침수 피해 예방을 위한 농촌 맞춤형 비즈니스 모델 설계)

  • Jo, Yerim;Lee, Jonghyuk;Seo, Byunghun;Kim, Dongsu;Seo, Yejin;Kim, Dongwoo;Choi, Won
    • Journal of Korean Society of Rural Planning
    • /
    • v.30 no.3
    • /
    • pp.9-17
    • /
    • 2024
  • Agricultural reservoirs play a crucial role in rural areas, providing essential water resources for agriculture. However, collapses or overfilling of reservoirs can lead to significant damages to both property and lives. Unfortunately, the safety of agricultural reservoirs is often uncertain due to aging infrastructure and lack of comprehensive safety management systems. Additionally, the escalating severity of climate change exacerbates these risks, because of extreme weather events. This study proposes a business model for a flood damage management platform tailored to rural areas to predict downstream flooding caused by agricultural reservoirs and to integrate comprehensive reservoir safety management. It aims to predict more accurate downstream flood damage using improved methods based on previous studies. The proposed business model presents strategies for providing improved downstream flood damage prediction services, and identifies potential customers and service supply strategies for the flood damage management platform. Finally, it presents an economic analysis of the proposed business model and strategies for further revenue generation.

Investigating the Determinants of Trust in the Internet Shopping Mall Environments: Focusing on the Moderation Effects of Perceived Risk and Perceived Price (인터넷 쇼핑몰에서의 신뢰 형성 요인에 관한 연구: 인지된 위험 및 가격의 조절효과를 중심으로)

  • Lee, Kyu-Ha;Kwahk, Kee-Young
    • Information Systems Review
    • /
    • v.17 no.2
    • /
    • pp.1-27
    • /
    • 2015
  • Internet shopping has continued to grow rapidly in the past decade. The main cause of this growth was the cheap price and convenience. However, internet shopping is uncertain compared to off-line shopping malls. Consumers don't have a chance to directly see and touch the products they will purchase. Many previous studies have suggested a trust to resolve this uncertainty. For purposes of the study, we examined how trust affects word-of-mouth effect and third-party assurance. Furthermore, using perceived risk and perceived price as moderating effects, we analyzed to see how each group-that is, those with high perceived risk and low perceived risk and those with high perceived price and low perceived price-shows differences in trust building. The results of empirical study found that both two variables of word-of-mouth effect and third-party assurance have significant impacts in trust building of internet shopping malls. It was proven that each group-those with high perceived risk and low perceived risk and those with high perceived price and low perceived price-showed differences in trust building. The results are expected to provide both the researchers of the trust study and hands-on worker with important implications.