• Journal of the military operations research society of Korea
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• v.25 no.2
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• pp.44-61
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• 1999

Cost estimation has posed a significant challenge to estimators, planners, and managers in both government and military. Considerable historical evidence shows that accurate cost estimation has been difficult to achieve across a wide range of projects, including weapon systems. This paper introduces new cost estimating concept, CAIV(Cost As an Independent Variable) and a cost estimating case study using PRICE model, computer aided parametric estimating models(CAPE) for K1 tank cost estimate. CAIV concept is to set realistic but aggressive cost objectives easily in each acquisition program and to achieve cost, schedule, and performance objectives considering various managing risks with a project manager and industry teams. The Price model is one of computer aided cost estimating models and widely used in U.S. defense system analysis as a tool for CAIV. We analyze theories, inputs, outputs of the PRICE model and present a case study for K1 tank to estimate costs in requirement and concept phase, program and budgeting phase, and life cycle phase. Finally we obtain results that the Price model can be used in various phases of PPBEES depending upon available data and time.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.2
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• pp.57-67
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• 2006

One of challenging issues of market oriented manufacturing organization is product proliferation. However, increasing product variety not only incurs additional direct and indirect production cost, but also aggravates production system performance such as inventory level, customer lead time and fill rate. Recently, as one of the most beneficial strategic choices to menage the risks associateed with product variety and uncertain sales, special attention is focused on the product/process redesign to delayed product differentiation. In this paper, we develop an analytical model to demonstrate the existence of an optimal level of product differentiation, which can be used to provide theoretical basis in establishing market oriented SCM strategy.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.699-722
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• 2019

It is difficult to observe the potential risks of lifting or turn-over operations in the early stages before a real operation. Therefore, many dynamic simulations have been designed to predict the risks and to reduce the possibility of accidents. These simulations, however, have usually been performed for predetermined and fixed scenarios, so they do not reflect the real-time control of an operator that is one of the most important influential factors in an operation; additionally, lifting or turn-over operations should be a collaboration involving more than two operators. Therefore, this study presents an integrated method for a collaborative simulation that allows multiple workers to operate together in the virtual world. The proposed method is composed of four components. The first component is a dynamic analysis that is based on multibody-system dynamics. The second component is VR (virtual reality) for the generation of realistic views for the operators. The third component comprises the control devices and the scenario generator to handle the crane in the virtual environment. Lastly, the fourth component is the HLA (high-level architecture)-based integrated simulation interface for the convenient and efficient exchange of the data through the middleware. To show the applicability of the proposed method, it has been applied to a block turn-over simulation for which one floating crane and two crawler cranes were used, and an offshore module installation for which a DCR (dual-crane rig) was used. In conclusion, the execution of the proposed method of this study is successful regarding the above two applications for which multiple workers were involved.

• Journal of Chest Surgery
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• v.35 no.4
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• pp.283-289
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• 2002

Backgrouds: It is almost universally accepted that occlusive vascular diseases are best managed by anatomical reconstruction. However, the mortality and the morbidity have limited this operation for patients with high operation risks. In these patients, palliative operations such as extra-anatomic bypass and lumbar sympathectomy, are accepted as useful treatment. Material and Method: A retrospective study was conducted in 38 patients who underwent palliative operations for occlusive vascular disease at Korea University Guro Hospital between 1996 and 2000. Mean age of the patients was 60.37 $\pm$ 17.65 years, and preoperative diagnoses were atherosclerosis in 32 patients, Buerger's disease in 4 patients, Raynaud's syndrome in 1 patient and SVC syndrome in 1 patient. Result: Extra-anatomic bypass(40procedures), lumbar sympathectomy(17), thromboembolectomy(7) and femoral artery graft interposition(1) were performed. Six patients were required reoperation due to graft flow failure or fistula. Three year primary patency rate of entire operations was 78.29 $\pm$ 8.81%, and the correlation between type of operation and patency rate was not statistically significant. Conclusion: Palliative operations for occlusive vascular disease are useful treatment in limited patients with high operation risks or limited life expectancy.

• The Journal of Information Technology
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• v.7 no.4
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• pp.103-117
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• 2004

The risk management industry has grown considerably in the past few years. Risk managers are entering the ranks of senior management, becoming a part of the decision making process and the oversight of its operations. Risks are inherent in any project. Furthermore, risk taking is essential to progress, and failure is often a key part of learning. Although some risks are inevitable, this does not mean that attempting to recognize and manage them will harm opportunities for creativity. Risk management is, and will remain, very much reliant on timely, clean and comprehensive data. Therefore, this paper was designed the current state of risk management practice, and planning the strategy of effectiveness risk management for company.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.888-894
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• 2015

This paper presents a unified model based assessment framework to quantify threats and vulnerabilities associated with control systems, especially in the SCADA (Supervisory Control and Data Acquisition) system. In the past, this system was primarily utilized as an isolated facility on a local basis, and then it started to be integrated with wide-area networks as the communication technology would make rapid progress. The introduction of smart grid, which is an innovative application of digital processing and communications to the power grid, might lead to more and more cyber threats originated from IT systems. However, an up-to-date power system often requires the real-time operations, which clearly implies that the cyber security would turn out to be a complicated but also crucial issue for the power system. In short, the purpose of this paper is to streamline a comprehensive approach to prioritizing cyber security risks which are expressed by the combination of threats, vulnerabilities, and values in the SCADA components.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.201-203
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• 2022

Increasing global market of used electric vehicle (EV) battery encourages international firms to establish its subsidiary companies or business units specializing in battery recycling. Such kind of companies predominantly use closed loop supply chain (CLSC) for their operations of battery manufacturing and used battery recycling/reusing in global scale. However, EV battery recycling, as a relatively new industry, makes its global CLSC be exposed to various types of risks, which leads to inefficiency of supply processes and makes supply chains more complicated and vulnerable. Identifying, evaluating, and analyzing possible risks in CLSC has a great importance for optimization and increasing effectiveness for the global supply chain of used EV battery. Itwill assist to elaborate the efficient CLSC management and possible risk mitigation strategies to keep the global EV battery supply chain resilient and sustainable. This study aims to develop a conceptual framework for risk assessment in this new sector. Therefore, it will populate the framework with possible failure modes identified from various literature on EV battery recycling and closed loop supply chains so that future research can validate and utilize the conceptual framework.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.527-532
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• 2020

Seoul terminal maneuvering area (TMA) that includes Incheon International Airport (ICN) and Gimpo International Airport is a very congested airspace with around 1,000 daily flights and the airspace blocked at the boundary between Incheon flight information region (FIR) and Pyongyang FIR. Consequently, with frequency radar vectorings, separation assurance in this airspace is complicated thus resulting in higher controller workload. In this paper, the conflict and collision risks in Seoul TMA are analyzed using recorded ADS-B data for past three years. Using the recorded trajectories, original flight plan procesures and routes are reconstructed and the risks are quantified using detect and avoid well clear (DWC) metric that is developed for large unmanned aircraft system. The region west of ICN was found to be the highest risk area regardless of the runway directions. In addition, merge and crossing points between procedures displayed relatively high risks.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.4
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• pp.11-33
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• 2013

We analyzed the structures and properties of the global financial market networks using social network analysis approach. The Minimum Spanning Tree (MST) lengths and networks of the global financial markets based on the correlation coefficients have been analyzed. Firstly, similar to the previous studies on the global stock indices using MST length, the diversification effects in the global multi-asset portfolio can disappear during the crisis as the correlations among the asset class and within the asset class increase due to the system risks. Second, through the network visualization, we found the clustering of the asset class in the global financial markets network, which confirms the possible diversification effect in the global multi-asset portfolio. Meanwhile, we found the changes in the structure of the network during the crisis. For the last one, in terms of the degree centrality, the stock indices were the most influential to other assets in the global financial markets network, while in terms of the betweenness centrality, Gold, Silver and AUD. In the practical perspective, we propose the methods such as MST length and network visualization to monitor the change of the correlation risk for the risk management of the multi-asset portfolio.

• Journal of the Korean Operations Research and Management Science Society
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• v.37 no.3
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• pp.79-94
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• 2012

According to the higher dependence of contemporary firms on data digitalization and the information technology, the role and importance of Information Security Management (ISM) is getting higher. Thus, there is a need to arrange proper procedure and a series of device within the organization in order to reduce diverse security risks, which take place from the inside and the outside of firm. In other words, prior examination for reinforcing recognition of ISM, and of a systematic performance method in the refined form is important. This study investigate the key variables influencing the ISM. Thus, this study suggests firm environmental factors that include four exogenous variables, market volatility, task interdependence, perceived benefits, and coordination mechanism affecting awareness of ISM. In addition, it proposes a concept of the ISM process with awareness, development, and performance, and examines the moderating effects of regulatory influence. The research model was tested by using Structural Equation Modeling, via SmartPLS 2.0 analysis on a sample collected from 186 employees in various industries. The research results provide the evidence that supports the tested hypotheses except significance of coordination mechanism. The implications of the findings suggest a new theoretical framework of the ISM and offers important solutions for the practical application guidelines.