• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.306-309
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• 2009

MANET(Mobile Ad-hoc Network)은 기간망에 의존하지 않는 이동 노드들로 구성된 자율망 또는 추론망 토폴로지에 의한 멀티홉 무선 네트워크이다. MANET을 구성하는 각 노드의 이동성, 속도 그리고 에너지와 같은 다양한 속성정보는 망의 특징과 운영을 결정하는 요인이다. 특히 망의 운영상, 전송 대역폭과 에너지 사용에 따른 제약을 가지며 이러한 특징을 고려한 라우팅 프로토콜의 설계 및 하드웨어 개발이 중요하게 요구된다. 본 논문에서는 계층적 클러스터 구조의 MANET 환경에서 노드의 에너지 속성과 네트워크의 트래픽 상태를 고려한 적응적 시간차 노드관리 기법인 ATICC(Adaptive Time Interval Clustering Control)을 제안한다. 제안된 ATICC은 시간차 노드 관리기법인 TICC(Time Interval Clustering Control)[1]에 기반하며 노드에 최적화된 Active/Sleep, Idle Listening 상태를 적응적으로 설정한 후 패킷을 전송함으로서 계층적 클러스터 내의 각 노드의 균형적인 에너지 소모를 이루는 에너지 효율적인 방식이다. 제안한 노드관리 방법은 기존의 LEACH, TICC과 비교 실험하고 그 성능을 검증하였다. 실험 결과, 제안한 노드관리 방법이 노드별 에너지 소모량을 줄였으며 전체 네트워크의 생존시간을 연장함으로서 기존의 방법 보다 우수함을 확인하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.273-276
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• 2008

A Through Bulkhead Initiation Module(TBIM) has been designed which guarantees the seal property without using O-ring. The TBIM works as the shock wave generated by a donor charge transmits to the acceptor charge. The structural safety of TBIM housing has been calculated via modeling analysis, and the ignition performance has been proved by 10 cc closed bomb test. The reliability analysis has been made using Probit method on the base of performance test results. According to the reliability analysis the bulkhead thickness of TBIM which is the most important design parameter has been determined.

• Journal of IKEEE
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• v.23 no.2
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• pp.469-473
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• 2019

In the case of renewable generation resources, the supply capacity is determined by the climate and environment factors unlike the existing generators. Therefore, it is necessary to calculate the capacity vlaue for estimating the supply capacity of renewable generation sources. In this paper, a case study on the estimation method of capacity vlaue of renewable generation resources and a verification using data of Jeju-Island power system are presented. This paper is different from the existing researches because of estimating the capacity value of renewable generation resources for the Jeju-Island power system, which has a high ratio of renewable generation.

• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.353-359
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• 2018

This study analyzes the academic achievement of students how much they are related to both NCS(national competency standards)-based education from university and the learning motives(internal motive, external motive) of the students based on current university students. For this study, a survey was conducted among 200 employees and are summarized as follow. First, that both internal and external motives to study were significant to have a good effect on academic achievement of students. Second, NCS-based education to have positive effect on academic achievement.

• Journal of the Korea Society of Computer and Information
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• v.26 no.4
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• pp.223-229
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• 2021

This study investigated the determinants of debt ratio in public institutions. For this purpose, we analyzed the impact of inefficient management as internal factors on debt ratio. In this paper, inefficient management included total costs, payment, and employee benefit. The results of this study are as follows. First, we find that there is a significant positive relation between total costs and debt ratio. This result means that the higher total costs, the higher debt ratio. Second, we find that there is not a significant relation between payment and debt ratio. And we also find that there is not a significant relation between employee benefit and debt ratio. These results are empirical results that can be answers about some concerns that inefficient management of public institutions worsen debt ratio.

• Korea Trade Review
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• v.44 no.2
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• pp.203-219
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• 2019

Recently, the Trump administration initiated a new United States-Mexico-Canada Agreement (USMCA) that strengthened NAFTA's rules of origin to enhance protectionism while maintaining the framework of trade agreements rather than completely abolishing them. This study focuses on the behavior of firms motivated to influence the government to practice protectionist trade by analyzing the rules of origin verification and adopting the political economics model. This paper explains the process of endogenous determination of the stringency of rules of origin verification as a non-tariff barrier using the lobbying model. Comparative static analysis shows that the more efficient technology a domestic firm has and the more government prefers to raise political contribution, the more is verification likely to be strict. This suggests that a rationale exists to maintain a free trade agreement in the form of the new agreement (USMCA) without abolishing the current NAFTA regime.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.3
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• pp.393-398
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• 2022

During the test operation period of the wind profiler prototype, radio frequency interference (RFI) contamination occurred in the spectrum. The reference of the RFI that removed the algorithm appearing in the wind profiler spectrum were investigated, and a new algorithm was developed to remove the RFI. First, it was filtered with a threshold value of 0.1 m/s of the spectral width, and the range of the number of gates with the same radial velocity was determined according to whether the beam was a vertical beam or an oblique beam. RFI contamination was removed through filtering and scanning of non-weather signals, and the continuity of wind vectors calculated from the improved spectral radial velocity was verified.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.6
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• pp.105-114
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• 2022

We examine berth allocation problems in tidal bulk ports with an objective of minimizing the demurrage and dispatch associated berthing cost. In the proposed optimization model inventory (or stock) level constraints are considered so as to satisfy the service level requirements in bulk terminals. It is shown that the mathematical programming formulation of this research provides improved schedule resolution and solution accuracy. We also show that the conventional big-M method of standard resource allocation models can be exempted in tidal bulk ports, and thus the computational efficiency can be significantly improved.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.189-189
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• 2022

물 공급 시설의 효율적이고 안정적인 운영을 위한 운영 계획의 수립 및 검증을 위해서는 장기간의 유입량 자료가 필요하다. 하지만, 현실적으로 얻을 수 있는 실측 자료는 제한적이며, 유입량이 부족하여 댐 운영에 영향을 미치는 자료는 더욱 적을 수밖에 없다. 이를 개선하고자 장기간의 모의 유입량을 생성해 운영 계획을 수립하는 방법이 종종 사용되지만, 실측 자료를 기반으로 모의하기 때문에 이 역시 가뭄의 빈도가 낮아, 장기 가뭄이나 짧은 간격으로 가뭄이 발생할 시 안정적인 운영이 어렵다. 본 연구에서는 장기 가뭄 발생 시에도 안정적인 물 공급이 가능한 운영 계획 수립을 위해 가뭄 빈도를 증가시킨 유입량 모의 기법을 제안하고자 한다. 제안하는 모의 기법은 최근 머신러닝에서 사용되는 SMOTE 알고리즘을 기반으로 한다. SMOTE 알고리즘은 데이터의 불균형을 처리하기 위한 오버 샘플링 기법으로, 소수 그룹을 단순 복제하지 않고 새로운 복제본을 생성해 과적합의 위험이 적으며, 원자료의 정보가 손실되지 않는 장점이 있다. 본 연구에서는 미국 캘리포니아주에 위치한 Folsom 댐을 대상으로 고빈도 가뭄 유입량을 모의했으며, 고빈도 가뭄 유입량을 사용한 운영 계획을 수립하였다. Folsom 댐의 과거 관측 유입량 자료를 기반으로 고빈도 가뭄 유입량을 사용한 운영 계획과 일반적인 가뭄 빈도의 유입량을 사용한 운영 계획을 적용했을 때 발생하는 공급 부족량과 과잉 방류량의 차이를 비교해 고빈도 가뭄 유입량의 사용이 물 공급 시설의 안정적인 운영에 끼치는 영향을 확인하고자 한다.

• Journal of the Korean Geotechnical Society
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• v.24 no.3
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• pp.5-11
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• 2008

This paper pertains to the incorporation of a genetic algorithm methodology for determining the critical slip surface and the corresponding factor of safety of soil slopes using inclined slice method. The analysis is formulated as a constrained optimization problem to solve the nonlinear equilibrium equations and finding the factor of safety and the critical slip surface. The sensitivity of GA optimization method is presented in terms of development of failure surface. Example problem is presented to demonstrate the efficiencies of the genetic algorithm approach. The results obtained by this method are compared with other traditional optimization technique.