• 산경연구논집
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• 제10권1호
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• pp.19-27
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• 2019

Purpose - The purpose of the paper is to examine disconnection between supply and demand shipping market, which means shipowner has determined to raise capacity in bust period. Research design, data, and methodology - The research method to be applied is first to look into conceptual theory about shipping market, and then to study imbalance of supply and demand situations in shipping on crisis, and next, to analyses paradoxical aspects traced. Results - Shipping market is a volatile and cyclic characteristics, and its situations have to be examined very carefully. Since financial crisis has broken up in 2008, it is natural to think that world trade volumes has reduced rapidly, which means demand for shipping service has fallen, and accordingly, tonnage should be stagnated as well. However, shipping companies have put capacity into market as unexpectedly. This is because of economy of scale and time lag. Here, this can be explained in terms of paradox that is proved in this paper. Conclusions - From careful research in this paper, it is found that supply and demand are not always got along with market situations, in other words supply side could be working well, in spite of depression time of demand situations in world shipping markets.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.436-445
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• 2013

The use of a demand response controller is necessary for electric devices to effectively respond to time varying price signals and to achieve the benefits of cost reduction. This paper describes a new formulation with the form of constrained optimization for designing an optimal demand response controller. It is demonstrated that constrained optimization is a better approach for the demand response controller, in terms of the ambiguity of device operation and the practicality of implementation of the optimal control law. This paper also proposes a design scheme to construct a demand response controller that is useful when a system controller is already adapted or optimized for the system. The design separates the demand response function from the original system control function while leaving the system control law unchanged. The proposed formulation is simulated and compared to the system with simple dynamics. The effects of the constraints, the system characteristics and the electricity price are examined further.

• Earthquakes and Structures
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• 제26권2호
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• pp.117-130
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• 2024

Probabilistic model of seismic demand is the main tool used for seismic demand estimation, which is a fundamental component of the new performance-based design method. This model seeks to mathematically relate the seismic demand parameter and the ground motion intensity measure. This study is intended to use Bayesian analysis to evaluate the accuracy of the seismic demand estimation of Steel moment resisting frames (SMRFs) through a completely Bayesian method in statistical calculations. In this study, two types of intensity measures (earthquake intensity-related indices such as magnitude and distance and intensity indices related to ground motion and spectral response including peak ground acceleration (PGA) and spectral acceleration (SA)) have been used to form the models. In addition, an extensive database consisting of sixty accelerograms was used for time-series analysis, and the target structures included five SMRFs of three, six, nine, twelve and fifteen stories. The results of this study showed that for low-rise frames, first mode spectral acceleration index is sufficient to accurately estimate demand. However, for high-rise frames, two parameters should be used to increase the accuracy. In addition, adding the product of the square of earthquake magnitude multiplied by distance to the model can significantly increase the accuracy of seismic demand estimation.

• Current Research on Agriculture and Life Sciences
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• 제31권2호
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• pp.139-147
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• 2013

This study analyzed agricultural water distribution systems for the utilization of water demand-oriented water supply systems. Three major TM/TC(telemeter/telecontrol) districts of agricultural water management were selected for analyzing the characteristics of the water distribution systems. In addition, the characteristics of the water supply systems for general water supply zones based on irrigation facilities were also investigated, along with the case of special water management during the drought season. As a result, high annual and monthly variations were observed for the water supply facilities, including the reservoirs and pumping stations. In particular, these variations were more obvious during the drought season, depending on the type of facility. The operations of the pumping stations and weirs were more sensitive to the stream levels than the reservoirs, and the smaller reservoirs were influenced more than the larger reservoirs. Therefore, a water-demand-oriented water supply system should consider the existing general practices of water management in the agricultural sector, and focus on achieving a laborsaving system rather than water conservation in the case of reservoirs. Equal water distribution from the start to the end point of irrigation channels could be an effective solution for managing pumping stations.

• 한국인터넷방송통신학회논문지
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• 제21권5호
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• pp.61-69
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• 2021

온디맨드 방송은 모바일 컴퓨팅 환경에서 데이터를 효과적으로 전송하기 위한 기술이다. 본 논문은 온디맨드 방송 환경에서 다중 데이터 질의를 스케줄링하기 위한 주제를 연구하여, CASS라 명명된 새로운 방송 스케줄링 기법을 제안한다. 제안된 기법은 다중 데이터 질의의 특성을 반영하여 질의의 우선순위를 정하고, 질의 우선순위에 따라 질의에서 가장 오랫동안 방송되지 않은 데이터를 방송 데이터로 선정한다. CASS 기법의 성능 평가를 위해 시뮬레이션이 수행되었다. 실험 결과에 따르면, 제안된 기법은 질의 데이터 인접성 및 데이터 충돌률 측면에서 매우 바람직한 특성을 보이기 때문에 평균 응답시간의 성능에서 다른 기법보다 우수한 성능을 보인다.

• Journal of Information Processing Systems
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• 제19권2호
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• pp.258-266
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• 2023

Aiming at the problems of poor customer satisfaction and poor accuracy of customer classification, this paper proposes a customer classification model based on speech recognition. First, this paper analyzes the temporal data characteristics of customer demand data, identifies the influencing factors of customer demand behavior, and determines the process of feature extraction of customer voice signals. Then, the emotional association rules of customer demands are designed, and the classification model of customer demands is constructed through cluster analysis. Next, the Euclidean distance method is used to preprocess customer behavior data. The fuzzy clustering characteristics of customer demands are obtained by the fuzzy clustering method. Finally, on the basis of naive Bayesian algorithm, a customer demand classification model based on speech recognition is completed. Experimental results show that the proposed method improves the accuracy of the customer demand classification to more than 80%, and improves customer satisfaction to more than 90%. It solves the problems of poor customer satisfaction and low customer classification accuracy of the existing classification methods, which have practical application value.

• 한국산학기술학회논문지
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• 제21권12호
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• pp.469-474
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• 2020

본 연구는 기존의 연구가 설명하지 못하는 저소득계층의 낮은 수요, 위험회피성향이 높을수록 낮은 수요를 보이는 점과 같은 소액보험의 특성을 건강보험에 관한 이론모형을 바탕으로 설명하고 있다. 특히 이러한 특성은 소득이 낮을 수록, 위험회피성향이 높을수록 보험 수요가 높다는 기존의 보험 이론과 배치되는 측면이 존재한다. 본 연구는 기존 1기간 모형에 비해 본 연구는 2기간 모형을 가정하고 있다. 그 결과 첫째, 기존 1기간 모형 하에서와 달리 소득의 감소가 언제나 질병 예방의 노력을 감소시킨다는 것을 보이고 있다. 둘째, 계리적으로 공정한 보험료 하에서 개인이 전부보험을 선택한다는 기존 연구결과와는 달리 소득이 낮은 경우 보험 수요가 낮아질 수 있다는 것을 보이고 있다. 셋째, 본 연구는 미래에 대한 전망이 개선될수록 보험 수요가 낮아질 수 있으며, 넷째, 위험회피성향이 증가할수록 보험수요가 증가해야 한다는 기존 연구결과와는 달리, 보험자에 대한 신뢰 부족 및 파산 우려가 큰 경우 위험회피성향이 증가할수록 보험수요가 오히려 낮아질 수 있다는 것을 이론적으로 증명하고 있다.

• 대한교통학회지
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• 제4권2호
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• pp.15-35
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• 1986

As the population of persons and automobiles rapidly grows, parking problems also grow in large cities of Korea. The purpose of this paper is to first grasp the status of parking facilities and characteristics in large cities of Korea; and introduce new directions of CBD parking policies in north America cities: and finally recommend the adequate parking management strategies and tactics for improving parking problems in Korea. For this purpose, field survey for parking inventories, patrol survey for parking usage as observed demand and drive interview survey for parking behavior were conducted. Compared with the parking characteristics and polices of foreign cities, many differences of characteristics were found, and existing parking management policies, which should be improved, were identified. Five categories of parking management strategies were set on; a) Reasonable control of CBD parking demand, b) securing of the public parking facilities c) Promotion of privately operated parking facilities d) expansion of financial resources for parking facilities construction and e) Improvement of existing parking management system. And actural seventeen tactics to attain the above strategies were recommended.

• 경영과정보연구
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• 제13권
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• pp.141-162
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• 2003

This article discusses the issues of the estimated size and characteristics of irregular employment work force in Korea after IMF economic crisis in 1997. The issues of the estimated size of irregular employment work force originated from different concepts and its operationalizations among the labor economists, despite their utilization of the same labor force data, 'Economically Active Population Survey(EAPA)' collected from Korea National Statistical Office(KNSO). And the issues contribute toward the understandings of the irregular employment and the limits of the EAPA, despite its various usefulness. This article also describes the summary characteristics of irregular employment work force from both sides of labor supply and its demand. The major characteristics of irregular employment work force on the labor supply side appears in the concentration of social minorities, i.e. woman, the aged, lower educated and skilled populations. On the labor demand of irregular employment work force, the majority of it concentrated on the establishments under 10 employees, and probably the important incentives for irregular employment work force of the firms is labor cost efficiency. Finally, this article propose an alternative against the discrimination between the regular and irregular work force.

• 동굴
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• 제90호
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• pp.63-68
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• 2009

동굴의 유형 분류를 학술적 근거에 두지 않고 동굴 내부의 다양한 특성 즉, 길이, 지형지물의 종류, 성인, 광장유무를 변수로 이용하였다. 분석 기법으로는 군집분석을 이용하였다. 분석 결과 5개의 유형으로 분류되었으며, 이러한 결과는 관람객의 요구에 따른 다양한 분류가 가능하다는 결과를 말해준다.