• Title/Summary/Keyword: system uncertainty

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Correction of Latent Errors in Pavement Deterioration Data using Statistical Methods (통계기법을 활용한 포장파손자료의 잠재오차 보정)

  • Han, Daeseok;Do, Myungsik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.6D
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    • pp.587-598
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    • 2012
  • Successful implementation of infrastructure asset management system can be started with rich and reliable data. However, measurement errors in the data have always existed in the real world caused for many unknown reasons. It disturbs maintenance activities of agencies, and makes negative effects to reliability of research results on forecasting deterioration process and life cycle cost. Above all, it makes a contradiction that road agencies cannot believe their inspection data surveyed by their hands. It is particularly serious in the road pavement management field. Although road agencies are well recognized the fact, inspecting without measurement error would be a great challenge. Considering the facts, this paper aimed to suggest statistical error processing methods to correct latent error included in pavement surface inspection data. As alternatives, this paper suggested two methods based on probability distribution to consider structure of error and reliability of the data. The suggested methods were empirically tested by using pavement inspection data from Korean National Highway. As the result, this paper confirmed that conventional error processing that just removes only visible errors is not enough to cover uncertainty in pavement deterioration process. The suggested methods would be useful for improving reliability of analysis results required for road infrastructure asset management.

Numerical Simulation of Urban Flash Flood Experiments Using Adaptive Mesh Refinement and Cut Cell Method (적응적 메쉬세분화기법과 분할격자기법을 이용한 극한 도시홍수 실험 모의)

  • An, Hyun-Uk;Yu, Soon-Young
    • Journal of Korea Water Resources Association
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    • v.44 no.7
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    • pp.511-522
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    • 2011
  • Two-dimensional shallow water model based on the cut cell and the adaptive mesh refinement techniques is presented in this paper. These two mesh generation methods are combined to facilitate modeling of complex geometries. By using dynamically adaptive mesh, the model can achieve high resolution efficiently at the interface where flow changes rapidly. The HLLC Reimann solver and the MUSCL method are employed to calculate advection fluxes with numerical stability and precision. The model was applied to simulate the extreme urban flooding experiments performed by the IMPACT (Investigation of Extreme Flood Processes and Uncertainty) project. Simulation results were in good agreement with observed data, and transient flows as well as the impact of building structures on flood waves were calculated with accuracy. The cut cell method eased the model sensitivity to refinement. It can be concluded that the model is applicable to the urban flood simulation in case the effects of sewer and stormwater drainage system on flooding are relatively small like the dam brake.

Preference-based Supply Chain Partner Selection Using Fuzzy Ontology (퍼지 온톨로지를 이용한 선호도 기반 공급사슬 파트너 선정)

  • Lee, Hae-Kyung;Ko, Chang-Seong;Kim, Tai-Oun
    • Journal of Intelligence and Information Systems
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    • v.17 no.1
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    • pp.37-52
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    • 2011
  • Supply chain management is a strategic thinking which enhances the value of supply chain and adapts more promptly for the changing environment. For the seamless partnership and value creation in supply chains, information and knowledge sharing and proper partner selection criteria must be applied. Thus, the partner selection criteria are critical to maintain product quality and reliability. Each part of a product is supplied by an appropriate supply partner. The criteria for selecting partners are technological capability, quality, price, consistency, etc. In reality, the criteria for partner selection may change according to the characteristics of the components. When the part is a core component, quality factor is the top priority compared to the price. For a standardized component, lower price has a higher priority. Sometimes, unexpected case occurs such as emergency order in which the preference may shift on the top. Thus, SCM partner selection criteria must be determined dynamically according to the characteristics of part and its context. The purpose of this research is to develop an OWL model for the supply chain partnership depending on its context and characteristics of the parts. The uncertainty of variable is tackled through fuzzy logic. The parts with preference of numerical value and context are represented using OWL. Part preference is converted into fuzzy membership function using fuzzy logic. For the ontology reasoning, SWRL (Semantic Web Rule Language) is applied. For the implementation of proposed model, starter motor of an automobile is adopted. After the fuzzy ontology is constructed, the process of selecting preference-based supply partner for each part is presented.

Concepts of Disaster Prevention Design for Safety in the Future Society

  • Noh, Hwang-Woo;Kitagawa, Keiko;Oh, Yong-Sun
    • International Journal of Contents
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    • v.10 no.1
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    • pp.54-61
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    • 2014
  • In this paper, we propose a pioneering concept of DPD(Disaster Prevention Design) to realize a securable society in the future. Features of danger in the future society are expected to be diverse, abrupt occurring, large scale, and complicated ways. Due to increment of dangers with their features of uncertainty, interactivity, complexity, and accumulation, human-oriented design concept naturally participates in activities to prevent our society against disasters effectively. We presented DPD is an essential design activity in order to cope with dangers expected in the future societies as well as realize securable environments. DPD is also an integrated design aids including preemptive protections, rapid preparing, recovery, and interactive cooperation. We also expect these activities of DPD is effective for generation of new values in the market, satisfaction of social needs, expansion of design industry, and a novel chance for development in the future society. Throughout this paper, we submit various aspects of DPD concepts including definition, classification, scope, necessity, strategy, influencing elements, process, and its principle. We expect these concepts will be the seed and/or basement of DPD research for the future works. For the direction of study for DPD in the future, we emphasize alarm system for preemptive protection rather than recovery strategy for the damage occurred. We also need to research about progressive prevention techniques and convergence with other areas of design. In order to transfer the concept of product design from facility-oriented mechanism to human-oriented one, we should develop new kinds of city basis facilities, public-sense design concepts referred to social weak-party, e-Learning content design preparing disasters, and virtual simulation design etc. On the other hand, we have to establish laws and regulations to force central and/or provincial governments to have these DPD strategies applying their regional properties. Modern design activities are expanding to UI(user interface) content design area overcoming the conventional design concept of product and/or service. In addition, designers are recognized as art directors or life stylists who will change the human life and create the social value. DPD can be divided into prevention design, preparedness design, response design, and recovery design. Five strategies for successful DPD are Precaution-oriented, Human-oriented, Sense-oriented, Legislation, and Environment Friendly Strategies.

Diachronic Network Analysis on Variable Factors for enhancing the Values of Apparel Industry in South Korea -Focused on Fashion Newspaper Articles- (한국 어패럴 산업의 가치 제고를 위한 변수 요인의 통시적 연결구조 분석 -패션 신문 기사를 중심으로-)

  • Kim, Jang-Hyeon;Lee, Ji-Yeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.2
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    • pp.551-564
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    • 2020
  • The fashion industry in Korea has grown into a core sector that contributes to the development of national industries, but it has shown negative growth due to the advent of a low-growth era. This study aims to explore core texts related to variable factors affecting the apparel industry in Korea (and the environmental change factors of apparel companies) by using network analysis from a diachronic point of view. In addition, we discuss the implications of enhancing the value of fashion industries in Korea based on articles in fashion newspapers over five years. The conclusion of this study is as follows. First, as a suggestion for political and economic aspects, the government should minimize the damage caused by political influence by presenting new policies, or by communicating about the practical aspects of geopolitical issues and changes linked to the fashion industry. Second, as a suggestion of socio-cultural aspects, it is necessary to reduce uncertainty about the future by establishing a strategic system through cooperation with institutions that can predict future directions. Third, as a suggestion for management changes in the apparel industry, apparel companies in Korea should recognize the importance of consciousness of promoting development for a better society from coexistence, rather than corporate profit.

Evaluation of Investment Value of Renewable Energy and Decision Making for Market Entry Using the Idle Space of Public Enterprises (공기업 유휴공간을 활용한 신재생에너지 투자사업에 대한 실물옵션기반 의사결정방안)

  • Na, Seoung Beom;Jang, Woosik;Kim, Kyeongseok;Kim, Byungil;Lee, Harry;Lee, Changgeun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.7
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    • pp.168-175
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    • 2020
  • Recently, there has been an increasing need to expand the supply of renewable energy as a solution to greenhouse gas emissions. Therefore, as a measure to promote domestic renewable energy investment and gradual expansion, this study analyzed the investment value of renewable energy projects utilizing the unoccupied spaces of public enterprise's facilities and presented a strategic decision-making framework to support efficient national land development and government measures. The NPV was estimated to be 286 million won if the expansion of the facility was not considered, but it is reasonable to postpone the expansion decision because the value of -130 million won was calculated if the expansion was considered. On the other hand, the real-option value was estimated to be 444 million won, taking SMP uncertainty, expansion, and abandonment options into account, and an additional value of 288 million won was calculated from an analysis of the expansion project using the existing NPV analysis.

Remedies for the Seller's Delivery of Defective Goods under EC Directive in Comparison with English Law, Korean Law and CISG (EC Directive상 하자물품에 대한 매수인의 구제제도에 관한 비교연구)

  • Lee, Byung-Mun
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.19
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    • pp.33-66
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    • 2003
  • This is a comparative and analytical study which comprises of the analysis of the rules of the buyer's remedies where the seller delivers defective goods of four legal systems; Directive, CISG, English law and Korean law. In light of threefold main purposes of this study, it firstly attempts to describe and analyze the remedy provisions of Directive in a comparative way in order to provide legal advice to the sellers who plans to enter into English consumer markets. It shows that the two tier remedial system under Directive is not much different from the other jurisdictions, except where the right of rescission under Directive is absolute in a sense that it does not require a certain degree of seriousness of defect. Secondly, the study compares the rules of one jurisdiction with those of other jurisdictions and evaluates the rules in light of the discipline of comparative law the basic question of which is whether a solution from one jurisdiction may facilitate the systematic development and reform of another jurisdiction. It proves the followings; (1) the reluctance and uncertainty in English law of ordering specific performance based on the discretionary power does not reflect the parties' preference because the order is either uncertain or rather negative where the purchase of substitute goods elsewhere is not a satisfactory solution in many cases; (2) the position in Korean law which has no limitation on the right to require substitute goods is likely unfair in commercial sales, but justified in consumer sales; (3) the right of termination or reduction under Directive which is subject to the applicability of the right to require repair or substitute goods seems to be contrary to the consumer's preference where the defective delivery destroys the basis of trust in the quality of the seller's performance; (4) the absolute right of termination under Directive and English law seems crucial in consumer sales because they are often inferior to commercial sellers in terms of information and bargaining power; (5) the right of reduction as a self-help remedy which is absent in English law emphasizes its usefulness. Thirdly, it finds that, where CISG is deemed to fail to unify different rules on the right to require specific performance between Civil and Common law, it is attempted once again in Directive and notwithstanding their hostility to awarding the right to require specific performance in English law, Regulations 2002 expressively stipulates such right.

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Principles and Current Trends of Neural Decoding (뉴럴 디코딩의 원리와 최신 연구 동향 소개)

  • Kim, Kwangsoo;Ahn, Jungryul;Cha, Seongkwang;Koo, Kyo-in;Goo, Yong Sook
    • Journal of Biomedical Engineering Research
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    • v.38 no.6
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    • pp.342-351
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    • 2017
  • The neural decoding is a procedure that uses spike trains fired by neurons to estimate features of original stimulus. This is a fundamental step for understanding how neurons talk each other and, ultimately, how brains manage information. In this paper, the strategies of neural decoding are classified into three methodologies: rate decoding, temporal decoding, and population decoding, which are explained. Rate decoding is the firstly used and simplest decoding method in which the stimulus is reconstructed from the numbers of the spike at given time (e. g. spike rates). Since spike number is a discrete number, the spike rate itself is often not continuous and quantized, therefore if the stimulus is not static and simple, rate decoding may not provide good estimation for stimulus. Temporal decoding is the decoding method in which stimulus is reconstructed from the timing information when the spike fires. It can be useful even for rapidly changing stimulus, and our sensory system is believed to have temporal rather than rate decoding strategy. Since the use of large numbers of neurons is one of the operating principles of most nervous systems, population decoding has advantages such as reduction of uncertainty due to neuronal variability and the ability to represent a stimulus attributes simultaneously. Here, in this paper, three different decoding methods are introduced, how the information theory can be used in the neural decoding area is also given, and at the last machinelearning based algorithms for neural decoding are introduced.

A study on uncertainty by passage of time of stereotactic body radiation therapy for spine metastasis cancer (척추 전이암 환자의 정위적방사선치료 시 시간 경과에 따른 불확실성에 관한 연구)

  • Cho, Yong Wan;Kim, Joo Ho;Ahn, Seung Kwon;Lee, Sang Kyoo;Cho, Jeong Hee
    • The Journal of Korean Society for Radiation Therapy
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    • v.27 no.1
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    • pp.79-86
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    • 2015
  • Purpose : The purpose of this study was to determine the proper treatment time of stereotactic body radiation therapy for spine metastasis cancer by using the image guidance system of CyberKnife(Accuray Incorporated, USA) which is able to correct movements of patients during the treatment. Materials and Methods : Fifty seven spine metastasis cancer patients who have stereotactic body radiation therapy of CyberKnife participate, 8 of them with cervical spine cancer, 26 of them with thoracic spine cancer, and 23 of them with lumbar spine cancer. X-ray images acquired during the treatment were classified by treatment site. From the starting point of treatment, motion tendency of patients is analyzed in each section which is divided into every 5 minutes. Results : In case of cervical spine, there is sudden increase of variation in 15 minutes after the treatment starts in rotational direction. In case of thoracic spine, there is no significantly variable section. However, variation increases gradually with the passage of time so that it is assumed that noticeable value comes up in approximately 40 minutes. In case of lumbar spine, sharp increase of variation is seen in 20 minutes in translational and rotational direction. Conclusion : Without having corrections during the treatment, proper treatment time is considered as less than 15 minutes for cervical spine, 40 minutes for thoracic spine, and 20 minutes for lumbar spine. If treatment time is longer than these duration, additional patient alignments are required or PTV margin should be enlarged.

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A Study on Technology Forecasting of Unmanned Aerial Vehicles (UAVs) Using TFDEA (TFDEA를 이용한 무인항공기 기술예측에 관한 연구)

  • Jung, Byungki;Kim, H.C.;Lee, Choonjoo
    • Journal of Korea Technology Innovation Society
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    • v.19 no.4
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    • pp.799-821
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    • 2016
  • Unmanned Aerial Vehicles (UAVs) are essential systems for Intelligence, Surveillance, and Reconnaissance (ISR) operations in current battlespace. And its importance will be getting extended because of complexity and uncertainty of battlespace. In this study, we forecast the advancement of 96 UAVs during the period of 32 years from 1982 to 2014 using TFDEA. TFDEA is a quantitative technology forecasting method which is characterized as non-parametric and non-statistical mathematical programming. Inman et al. (2006) showed that TFDEA is more accurate in forecasting compared with classical econometrics (e.g. regression). This study got 4.06% point of annual technological rate of change (RoC) for UAVs by applying TFDEA. And most UAVs in the period are inefficient according to the global SOA frontiers. That is because the countries which develop UAVs are in the middle class of technological level, so more than 60% of world UAVs markets are shared by North America and Europe which are advanced countries in terms of technological maturity level. This study could give some insights for UAVs development and its advancement. And also can be used for evaluating the adequacy of Required Operational Capability (ROC) of suggested future systems and managing the progress of Research and Development (R&D).