• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.213-215
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• 1995

This paper is concerned with a coplanar pursuit-evasion game of one inertial evader and two identical noninertial pursuers. The terminal time is fired and the payoff is the distance between the evader and the nearest pursuer when tile game is terminated. The value functions and the strategies is constructed for all the game surface. To get a value function, we use the generalization of the Bellman-Isaacs fundamental equation.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.7
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• pp.255-264
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• 2021

The purpose of this study is to analyze the role of customer value and customer trust as a mediator of flexibility influence on customer retention. The study applies SEM tools with WarpPLS analysis and translates customer value and customer trust as mediation. This study was organized into three parts: exploratory research, descriptive research, and explanatory research. The quantitative approach in this study uses a survey method by taking samples from the population. This is a latent variable that is measured using a research instrument in the form of a questionnaire. The survey was conducted by distributing questionnaires to respondents. This research was conducted at PT. Nusa Prima Logistics Terminal Teluk Lamong by taking primary data, in the form of assessments or perceptions from respondents, so a survey was conducted by submitting a questionnaire directly to 194 respondents. Quantitative data analysis was performed using Structural Equation Modeling (SEM) to answer the research hypothesis. Flexibility is very influential in increasing customer retention so to develop customer retention, it is necessary to increase flexibility, customer value, and customer trust. The novelty in this research lies in identifying the role and position of customer value and customer trust as mediation that affect customer retention.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.165-174
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• 2006

In this paper, we propose a new contention window control algorithm to increase TCP performance in wireless multi-hop networks. The new contention window control algorithm is suggested to reduce the hidden and exposed terminal problems of wireless multi-hop networks. Most of packet drops in wireless multi-hop networks results from hidden and exposed terminal problems, not from collisions. However, in normal DCF algorithm a failed user increases its contention window exponentially, thus it reduces the success probability of fined nodes. This phenomenon causes burst data transmissions in a particular node that already was successful in packet transmission, because the success probability increases due to short contention window. However, other nodes that fail to transmit packet data until maximum retransmission attempts try to set up new routing path configuration in network layer, which cause TCP performance degradation and restrain seamless data transmission. To solve these problems, the proposed algorithm increases the number of back-of retransmissions to increase the success probability of MAC transmission, and fixes the contention window at a predetermined value. By using ns-2 simulation for the chain and grid topology, we show that the proposed algorithm enhances the TCP performance.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.250-262
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• 2007

Statement of problem: It was reported high success rate of implant-supported fixed prostheses using with $5{\sim}6$ implants on anterior mandible. Recently, immediate loading protocol was focused to overcome disadvantages of classic 2-stage delayed loading protocol. Purpose: This clinical study was to evaluate stability changes with time of immediately loaded and delayed loaded implants in edentulous mandible and to compare stability changes with time according to implantation sites. Materials and methods: Five or six implants were placed on anterior mandible depending on the arch shape. The immediately loading group was consisted of 8 patients received their prostheses within $24{\sim}48$ hours after implantation. The delayed loading group was consisted of 8 patients received their definitive prostheses following classical prosthetic procedures after a healing period of 3 months. All patients were recalled every 6 months for check-up. The evaluations of radiographic examination, ISQ value measurement and recording of complication were done. To evaluate marginal bone level, intraoral periapical radiographs were taken with long cone paralleling technique. At every evaluation recall, all prostheses were removed and ISQ values were measured with OsstellTM on individual implants. Results: 1. None of implants was failed. All implants showed stable marginal bone levels and ISQ values. 2. Marginal bone level changes with time showed statistically significant difference between immediately loading group and delayed loading group (P<0.001). 3. ISQ value changes with time did not show statistically significant difference between immediately loading group and delayed loading group (P=0.079). ISQ value decreased with time in both groups, however, all implants showed stable ISQ value at 30 months-recall evaluation. 4. Marginal bone level changes with time did not show statistically significant differences among implantation sites (P=0.604). 5. ISQ value changes with time showed statistically significant differences among implantation sites (P=0.047). ISQ values of most posterior implants decreased with time comparing to other implants. Conclusion: Although the marginal bone level of the terminal abutment didn't different with the other implants, ISQ value of the terminal abutment was lower than that of the other implants. Therefore, further clinical evaluation would be needed in this point of view.

• Journal of Korea Port Economic Association
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• v.39 no.1
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• pp.149-172
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• 2023

In the Northeast Asian region, including Korea, China, and Japan, with rapid economic growth since the 1990s, intra-regional oil logistics has been increasing. Under such external circumstances, Korea has been pursuing a policy to become a Northeast Asian petroleum logistics hub since the mid-2000s. In order to become a Northeast Asian logistics hub, it is important to establish and promote a business model to promote the value-added oil logistics business. This study aims to propose policies and practical implications for increasing petroleum logistics by analyzing Korea's petroleum logistics business model in Northeast Asia. The results of case analysis through interviews with 23 tank terminal companies are as follows. First, most of the oil storage tank terminal companies interviewed are conducting value-added petroleum logistics such as blending, breaking bulk, and consolidation etc. Second, value-added petroleum logistics is caused by an imbalance in supply and demand among neighboring countries in Northeast Asia. In particular, there is a high demand for breaking bulk and blending connecting Japan, Oceania, the United States, and South America. Third, it is necessary to promote the promotion of value-added logistics by improving infrastructure, institutions, and regulations in response to the demand for value-added petroleum logistics, which will greatly contribute to Korea's policy for being Northeast Asian oil hub.

• Journal of Korea Port Economic Association
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• v.32 no.4
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• pp.127-147
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• 2016

This study proposes the improvement scheme of the current lease rate assessment system (2003~2014), as a major problem solving area, for the Terminal Operating Company (TOC)'s wharf since the introduction of the TOC system in 1997. The study considers the reform system using three criteria: standardization, simplification, and fairness. The final alternative presented by the study adopts the lease rate assessment system, which newly reflects changes of facilities' property values for aprons, combining it with the related fees of the Korean seaport dues for open storage yards, warehouses (shed), passages, buildings and lands within leased facilities. The proposal anticipates that the new system will not only minimize stakeholders' confusion, but also resolve the main problems within the current system. The study, further, introduces the adjustment ratio, which will make the new lease rate of the apron equal to the current lease rate of a berth, for the individual TOC's wharf, in order to prevent a sharp increment in the lease rate of the apron. This is because the government or port authorities as lessors, need to give priority to lightening the burden of TOC's costs under the deteriorating business environment such as the slowdown in port throughputs' growth. This study makes a contribution by suggesting a new lease rate assessment system for the TOC's wharf, reflecting the value of property as well as leading to its simplification and standardization. Additionally, it may lead to the improvement of fairness by applying the same rate to all leased wharfs for the lease rates of open storage yards, warehouses (shed) and passages. However, it has a limitation that hinders the fairness: the lease rate for the apron cannot be imposed in proportion to the leased area, by applying the individual adjustment ratios. In the future, those adjustment ratios should be, gradually, rationalized to be the same target ratio (0.5) for each wharf, following an improvement in the terminal operating business environment.

• Bulletin of the Korean Mathematical Society
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• v.53 no.3
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• pp.793-819
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• 2016

In this paper, we establish the existence and uniqueness of the solution for a class of reflected backward stochastic differential equations with time delayed generator (RBSDEs with time delayed generator, in short) in the case when the terminal value and the obstacle process are $L^p$-integrable with p ${\in}$]1, 2[ for a sufficiently small Lipschitz constant of the generator and the time horizon T.

• 전기의세계
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• v.22 no.4
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• pp.11-16
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• 1973

This paper presents an optimum control of the field resistance for the self-excited DC shunt generator to keep a constant terminal voltage in case of the load change or the torque variation in the system. The non-linearity of the system is linearized by applying the small signal technique and the linearized equation is solved by the maximum principle with the digital computer. The optimal control value of the field resistance for the step error of the generator output voltage is obtained and the transient voltage characteristics in the system are investigated.

• 전기의세계
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• v.49 no.9
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• pp.17-24
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• 2000

This paper presents sufficient conditions7 for monotonicity of the saddle point value for receding-horizon H$\infty$ control(RHHC). The resulting monotonicity is used to prove the stability of the closed-loop. Under these sufficient conditions the well-known terminal equality condition is handled as a special case and the condition on the state weighting matrix is weakened so as to include even the zero matrix. The whole procedure is much simpler than the previous results and thus is expected to be easily extended for constrained delayed and/or nonlinear systems with the RHHC.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.446-448
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• 2001

We have developed the testing software for KEPCO operators to maintain the small-scale distribution automation system effectively. The testing software is used to monitor the present status, to measure the analog value(voltage, amperage) and to control the switch and FRTU(Feeder Remote Terminal Unit) in order to find out a disabled part of the system. And at the stage of inspection of the switch and FRTU, it can screen the inferior one.