• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.47-54
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• 2016

Microgrids offer several reliability benefits, such as the improvement of load-point reliability and the opportunity for reliability-differentiated services. The primary goal of this work is to investigate the impacts of operating condition on the reliability index for microgrid system. It relies on a component failure rate model which quantifies the relationship between component failure rate and state variables. Some parameters involved are characterized by subjective uncertainty. Thus, fuzzy numbers are introduced to represent such parameters, and an optimization model based on Fuzzy Chance Constrained Programming (FCCP) is established for reliability index calculation. In addition, we present a hybrid algorithm which combines scenario enumeration and fuzzy simulation as a solution tool. The simulations in a microgrid test system show that reliability indices without considering operating condition can often prove to be optimistic. We also investigate two groups of situations, which include the different penetration levels of microsource and different confidence levels. The results support the necessity of considering operating condition for achieving accurate reliability evaluation.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.3
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• pp.91-104
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• 2008

This study developed the WSM (weighted scenario method)-AHP method that can optimize the weighting value for multi-criteria to make GIS grid-based potential surface. The potential surface has been used to simulate urban expansion using distributed cellular automata model and to generate land-use planning as basic data. This study formulated the WSM-AHP method in mathematically and applied to test region, Suwon city, which located on south area from Seoul. WSM-AHP method generates potential map for each pair of weighting value for all criteria, which one criterion is weighted with high weighting value and the others use low weighting value, considering that the summation for all criteria weighting values should be "1". The potential change rate to the step of weighted scenario for weighting value of criteria is standardized like AHP intensity matrix in this study. From the standard potential change rate, WSM-AHP intensity matrix is completed, and then the optimal weighting value is calculated from the maximum eigenvector of the WSM-AHP matrix, according to the new WSM-AHP method developed in this study. The applied results of new method showed that the optimal weighting value from WSM-AHP is more resonable than the general AHP specialists' evaluation for weighting value. The another new finding of this study is to suggest the deterministic approach to optimize the weighting value for the distributed CA model, which is used to find new city area and to generate rational land-use planning.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.595-598
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• 2004

In recognizing knowledge as a new resource in gaining organizational competitiveness, knowledge management suggests a method in managing and applying knowledge for improving organizational performance. Much knowledge management research has focused on identifying, storing, and disseminating process related knowledge in an organized manner. Applying knowledge to decision making has a significant impact on organizational performance than solely processing transactions for knowledge management. In this research, we suggest a method of knowledge-based decision-making using system dynamics, with an emphasis to strategic problems. The proposed method transforms individual mental models into explicit knowledge by translating partial and implicit knowledge into an integrated knowledge model. The scenario-based test of the organized knowledge model enables decision-makers to understand the structure of the target problem and identify its basic cause, which facilitates effective decision-making. This method facilitates the linkage between knowledge management initiatives and achieving strategic goals and objectives of an organization.

• Journal of Computing Science and Engineering
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• v.5 no.1
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• pp.51-70
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• 2011

This paper introduces a new credit card payment scheme called No Number Credit Card that can significantly reduce the possibility of credit card fraud. The proposed payment system is loosely based on Kerberos, a cryptographic framework that has stood the test of time. In No Number Credit Card, instead of card numbers, only payment tokens are exchanged between the customers and merchants. The tokens are generated based on the payment amount, payment type, client information, and merchant information. However, it does not contain the credit card number, so the merchant or a database hacker cannot acquire and illegally use any credit card numbers. The No Number Credit Card system is ideal for online e-commerce transactions and can be used with any credit card that users possess. It can be used with minor modifications to the current card payment system. We provide the principles of its operation through scenario analysis, a sample implementation, and a security analysis

• Journal of the Korea Safety Management & Science
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• v.17 no.3
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• pp.195-204
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• 2015

The live fire test has been playing a critical role in evaluating the goals-to-meet of the weapon systems which utilize the power of explosives. As such, the successful development of the test systems therein is quite important. The test systems development covers that of ranges and facilities including system-level key components such as mission control, instrumentation or observation, safety control, electric power, launch pad, and so on. In addition, proper operational guidelines are needed with well-trained test and operation personnel. The emerging weapon systems to be deployed in future battle field would thus have to be more precise and dynamic, smarter, thereby requiring more elaboration. Furthermore, the safety consideration is becoming more serious due to the ever-increasing power of explosives. In such a situation, development of live fire test systems seems to be challenging. The objective of the paper is on how to incorporate the safety and other requirements in the development. To achieve the goal, an architectural approach is adopted by utilizing both the system components relationship and safety requirement when advanced instrumentation technology needs to be developed and deteriorated components of the range are replaced. As an evaluation method, it is studied how the level of maturity of the test systems development can be assessed particularly with the safety requirement considered. Based on the concepts of both systems engineering and SoS (System-of-Systems) engineering process, an enhanced model for the system readiness level is proposed by incorporating safety. The maturity model proposed would be helpful in assessing the maturity of safety-critical systems development whereas the costing model would provide a guide on how the reasonable test resource allocation plan can be made, which is based on the live fire test scenario of future complex weapon systems such as SoS.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.2
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• pp.142-151
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• 2018

In the era of the 4th Industrial Revolution, research and development on autonomous vehicles have been actively conducted all over the world. Under these international trends, the Ministry of Land, Infrastructure and Transport is actively promoting the development of autonomous vehicles aiming at commercialization of autonomous vehicles at level 3 or higher by 2020. In the level 3 autonomous vehicle, it is essential to transfer control between the driver and the vehicle according to driving situations. Prior to the full-fledged autonomous vehicle age, this study developed a representative scenario for the safety evaluation on take-over on expressways. To accomplish this, we developed a highway driving scenario first, and then developed six control transition scenarios based on 2014 highway traffic accident data and take-over data. The variables to be considered in the developed scenarios are divided into drivers, vehicles, and environmental factors. A total of 36 variables are selected.

• Korean Journal of Community Nutrition
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• v.8 no.4
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• pp.556-565
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• 2003

Market segmentation helps providers to find better marketing opportunities and allows foodservice managers to develop the right product for each target market. Therefore, this study, taking university faculty and staff as subject, is intended to diagnose the relative value of service quality attribute, on the basis service quality scenario of faculty foodservice; to suggest price for improving customer loyalty in market segments. A questionnaire was developed ar d mailed to 600 Yonsei university faculty and staffs. A total of 385 questionnaires were usable; resulting in a 58.7％ of faculty and a 69.7％ of staff response rate, respectively. Statistical data analysis was completed using the SAS/Win 6.12 for descriptive Analysis, ANOVA, principal factor analysis, cluster analysis, reliability test and discriminant analysis. The results of the study are as below. Eighteen questions were selected for measuring respondents' lifestyle by AIO method and the seven lifestyle factors derived from factor analysis and aggregated distinct 4 clusters. Service quality attributes of the scenario were determined with 'food quality', 'menu variety', 'atmosphere', 'fast service', and 'clean and sanitation'. 'Food quality', 'menu variety', 'atmosphere', 'fast service', and 'clean and sanitation', in decreasing order, were identified as improving customer loyalty. However, most faculty and staffs were satisfied with the present meal price. The result of this study indicates that the relative value of service quality was differed significantly among the various market segments. 'Food quality', 'menu variety', and 'atmosphere' were determined as major service quality attributes. Thus, customer loyalty could be increased by improving food taste and quality, atmosphere, and service delivery. (Korean J Community Nutrition 8(4) : 556 ∼565, 2003)

• Journal of Navigation and Port Research
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• v.45 no.6
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• pp.360-365
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• 2021

LTE-maritime, which was built as part of the Korean e-Navigation project, has been providing a service that meets the goal of establishing a network up to 100km from the coast since J anuary 31, 2021. To provide appropriate communication services for LTE-maritime from the perspective of real users, additional performance analysis of LTE-maritime is required considering service implementation, and efficient use of spectrum resources. This paper presents the requirement of transmission speed according to the e-Navigation service scenario, and available transmission speed based on LTE modulation coding scheme (MCS) according to sea-specific ship distribution scenario and frequency resource allocation, and is cross-analyzed with results of the sea test.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.11
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• pp.1051-1058
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• 2012

The unified lateral control algorithm for automatic valet parking for various types of vehicles is presented and its feasibility is shown experimentally via field tests for the given parking scenario. First, a trajectory generation algorithm for forward driving and backward multi-step parking maneuvers is developed. Then, with consideration of different types of vehicles and operating conditions, a kinematic vehicle model is used and validated using field test data. Using the nonlinear vehicle model, the lateral controller is designed based on dynamic surface control. Finally the proposed lateral control law is validated via hardware-in-the-loop simulations for different types of vehicles and experimentally using a test vehicle through field tests.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.248-251
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• 2015

High injury and fatality rates remain a serious problem in the construction industry. Many construction injuries and fatalities can be prevented if workers can recognize potential hazards and take actions in time. Many efforts have been devoted in improving workers' ability of hazard recognition through various safety training and education methods. However, a reliable approach for evaluating this ability is missing. Previous studies in the field of human behavior and phycology indicate that the visual focus of attention (VFOA) is a good indicator of worker's actual focus. Towards this direction, this study introduces an automated approach for estimating the VFOA of equipment operators using a head orientation-based VFOA estimation method. The proposed method is validated in a virtual reality scenario using an immersive head mounted display. Results show that the proposed method can effectively estimate the VFOA of test subjects in different test scenarios. The findings in this study broaden the knowledge of detecting the visual focus and distraction of construction workers, and envision the future work in improving work's ability of hazard recognition.