• 한국항해항만학회지
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• 제26권2호
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• pp.189-192
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• 2002

우리나라 대부분의 어선은 침수 및 전복에 의해 야기되는 해양사고에 있어 그 빈도가 높으며, 특히 24m이하의 소형어선에서 두드러진다. 그럼에도 불구하고 소형어선에 대한 복원성 기준이 없을 뿐 아니라 소형어선의 복원성 자료를 찾기란 그리 쉽지 않다. 이에 본 연구에서는 90년 이후 표준어선으로 고시되어 건조 실적이 있는 실적선 10척에 대해 계측된 자료를 활용하여 이를 기초로 Genetic Programming을 이용한 GM 추정식을 도출하였다. 또한 국외 복원성 기준과 GP 추정식을 이용 각각에 대해서 GM을 평가하여, Genetic Programming에 의한 GM추정의 타당성을 보였다. 하지만, 이러한 결과값이 사용되기 위해서는 보다 많은 실적선 Data를 이용한 추론이 요구된다.

• 대한교통학회지
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• 제19권6호
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• pp.171-182
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• 2001

본 연구는 지점검지체계와 구간검지체계와의 자료합성을 통하여 도심 간선도로 및 지방도로 구간별 효과척도를 산정할 뿐만 아니라 유고검지 및 통행패턴 예측, 네트워크 기종점에 대한 최적/최단 경로를 탐색하는데 기초가 되는 구간 통행시간 추정을 수행한다. 개개 수집원의 자료합성을 위해 퍼지이론과 인공신경 망의 합성모형인 FALEM(Fuzzy Adaptive Learning Estimator for travel time from Multi-information sources)을 개발, 개발된 모형 FALEM에 의해 개개구간의 통행시간을 산출하고 동일시간, 동일구간에서 조사된 실측데이터와의 오차율 비교를 통해 추정된 통행시간을 검증하였다. 테스트 환경은 개발모형에 의해 추정된 구간 통행시간의 적용성을 고려하여 실시간 운영하에서 수행되었다.

• Journal of Power Electronics
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• 제17권4호
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• pp.914-922
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• 2017

Multilevel converters have attracted a lot of attention in recent years. The efficiency parameters of a multilevel converter such as the switching losses and total harmonic distortion (THD) mainly depend on the modulation strategy used to control the converter. Among all of the modulation techniques, the selective harmonic elimination (SHE) method is particularly suitable for high-power applications due to its low switching frequency and high quality output voltage. This paper proposes a new expression for the SHE problem in five-level converters. Based on this new expression, a simple analytical method is introduced to determine the feasible modulation index intervals and to calculate the exact value of the switching angles. For each selected harmonic, this method presents three-level or five-level waveforms according to the value of the modulation index. Furthermore, a flowchart is proposed for the real-time implementation of this analytical method, which can be performed by a simple processor and without the need of any lookup table. The performance of the proposed algorithm is evaluated with several simulation and experimental results for a single phase five-level diode-clamped inverter.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권6호
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• pp.1849-1876
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• 2022

Wireless Sensor Network (WSN) is considered as an integral part of the Internet of Things (IoT) for collecting real-time data from the site having many applications in industry 4.0 and smart cities. The task of nodes is to sense the environment and send the relevant information over the internet. Though this task seems very straightforward but it is vulnerable to certain issues like energy consumption, delay, throughput, etc. To efficiently address these issues, this work develops a cross-layer model for the optimization between MAC and the Network layer of the OSI model for WSN. A high value of duty cycle for nodes is selected to control the delay and further enhances data transmission reliability. A node measurement prediction system based on the Kalman filter has been introduced, which uses the constraint based on covariance value to decide the scheduling scheme of the nodes. The concept of duty cycle for node scheduling is employed with a greedy data forwarding scheme. The proposed Duty Cycle-based Greedy Routing (DCGR) scheme aims to minimize the hop count, thereby mitigating the energy consumption rate. The proposed algorithm is tested using a real-world wastewater treatment dataset. The proposed method marks an 87.5% increase in the energy efficiency and reduction in the network latency by 61% when validated with other similar pre-existing schemes.

• Steel and Composite Structures
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• 제48권3호
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• pp.321-333
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• 2023

This paper proposes a comprehensive investigation on lateral stiffness of corner-supported steel modular frame using splice connection. A full-scale modular frame with two stacked steel modules under lateral load is tested. Ductile pattern in the transfer of lateral load is found in the final failure mode. Two types of lateral stiffness, including tangent stiffness and secant stiffness, are defined from the load-displacement due to the observed nonlinearity. The difference between these two types of stiffness is found around 20%. The comparisons between the experimental lateral stiffness and the predictions of classical methods are also conducted. The D-value method using hypothesis of independent case is a conservative option for predicting lateral stiffness, which is more recommended than method of contraflexural bending moment. Analyses on two classical short-rod models, including fix-rod model and pin-rod model, are further conducted. Results indicate that fix-rod model is more recommended than pin-rod model to simplify splice connection for simulation on lateral stiffness of modular frame in elastic design stage.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.99-106
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• 2011

Recent demands from construction industry have emphasized the capability for graduates to have improved skills both technical and non-technical such as problem solving, interpersonal communication. To satisfy these demands, problem-based learning that is an instructional method characterized by the use of real world problem has been adopted and has proven its effectiveness various disciplines. However, in spite of the importance of field senses and dealing with real problem, construction engineering education has generally focused on traditional lecture-oriented course. In order to improve limitations of current construction education and to satisfy recent demands from construction industry, this paper proposes a new educational approach that is Failure-Based Learning for using combination of the procedural characteristics of the problem-based learning theory in construction technology education utilizing failure information that has the educational value in the construction area by reinterpreting characteristics of construction industry and construction failure information. The major results of this study are summarized as follows. 1) Educational effect of problem-based learning methodology and limitation of application in construction area 2) The educational value of the information on construction failure and limitation in application of the information in construction sector 3) Anticipated effect from application of the failure-based learning 4) Development and application of the failure-based learning model

• 한국경영정보학회:학술대회논문집
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• 한국경영정보학회 2008년도 춘계학술대회
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• pp.129-134
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• 2008

Dividend is one of essential factors determining the value of a firm. According to the valuation theory in finance, discounted cash flow (DCF) is the most popular and widely used method for the valuation of any asset. Since dividends play a key role in the pricing of a firm value by DCF, it is natural that the accurate prediction of future dividends should be most important work in the valuation. Although the dividend forecasting is of importance in the real world for the purpose of investment and financing decision, it is not easy for us to find good theoretical models which can predict future dividends accurately except Marsh and Merton (1987) model. Thus, if we can develop a better method than Marsh and Merton in the prediction of future dividends, it can contribute significantly to the enhancement of a firm value. Therefore, the most important goal of this study is to develop a better method than Marsh and Merton model by applying artificial intelligence techniques.

• 에너지공학
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• 제14권3호
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• pp.167-172
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• 2005

본 연구에서는 가치에 기반을 두고 배전시스템을 계획할 수 있는 방법을 제시하였다. 우선, 신뢰도를 평가하기 위하여 VBDRA를 도입하였으며, 고조파를 평가하기 위하여 한계가격기법을 도입하였다. 그리고, 신뢰도비용, 고조파비용, 건설비용을 사용하여 가장 경제적인 대체안을 결정을 할 수 있도록 하였다. 제안한 방법을 실제시스템에 적용하여 그 유용성을 입증하였다.

• 한국경영과학회지
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• 제33권2호
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• pp.75-86
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• 2008

A remarshalling is one of the operational strategies considered importantly at a port container terminal for the fast ship operations and heighten efficiency of slacking yard. The remarshalling rearranges the containers scattered at a yard block in order to reduce the transfer time and the rehandling time of container handling equipments. This Paper deals with the rearrangement problem, which decides to where containers are transported considering time value of each operations. We propose the mixed integer programming model minimizing the weighted total operation cost. This model is a NP-hard problem. Therefore we develope the heuristic algorithm for rearrangement problem to real world adaption. We compare the heuristic algorithm with the optimum model in terms of the computation times and total cost. For the sensitivity analysis of configuration of storage and cost weight, a variety of scenarios are experimented.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.32-41
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• 1999

In this study, a new knocking control algorithm was developed using the knock threshold value auto-correction algorithm. This algorithm uses the Fast Fourier Transform9FFT) method by measuring cylinder block vibration signals of a 1498 cc four-cylinder spark ignition engine. The experimental results show the proposed knock control algorithm provides improved performance compared to existing methods. The results also show that the proposed FFT algorithm provides real-time adjustment of the knock threshold value.