• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1992년도 제2회 정기총회 및 추계학술 발표회 발표논문 초록
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• pp.1-1
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• 1992

This paper presents a user-oriented port expansion simulation model that determines the future economic port capacity to meet the projected demand. The model consists of two parts; a physical impact simulation, and an economic impact simulation. The first part of the model simulates the effects caused by the port capacity expansion. The second part evaluates the port economics due to changes in the port capacity. The model was validated by applying it to the actual port expansion followed at the Port of Mobile, Alabama. A case study is then presented to demonstrate the capacity of the model with a coal handling port, the McDuffie Terminals at the Port of Mobile.

• 한국항만경제학회지
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• 제25권3호
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• pp.251-268
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• 2009

본 논문은 서비스 품질이 서로 다른 두 항만의 가격경쟁을 게임모형을 이용해 이론적으로 분석하고 있다. 화주들의 위치를 두 가지로 가정하였다. 하나는 두 항만의 한곳에 화주들이 밀집된 경우이고, 다른 하나는 두 항만 사이에 화주들이 고루 배치된 경우이다. 분석결과를 요약하면, 다음과 같다. 화주가 두 항만 사이의 특정 위치에 밀집되어 있을 경우, 화주들의 고품질 서비스에 대한 선호도가 커질수록 두 항만의 가격이 높아지나, 고품질 항만의 가격이 저품질 항만의 가격보다 2배 이상 빠르게 증가한다. 화주들의 위치가 고품질 항만쪽에 가까울수록 고품질 항만의 가격은 올라가고, 저품질 항만의 가격은 떨어진다. 또한, 운송비가 올라가면 저품질 항만의 가격은 낮아지나, 고품질 항만의 가격은 올라갈 가능성이 높다. 고품질 항만의 서비스가 상대적으로 더 높아지면, 고품질 항만의 가격은 올라가고, 저품질 항만의 가격 변화는 불확실하다. 다음으로 화주가 두 항만사이에 균질하게 분포할 경우, 화주들의 고품질 항만 서비스에 대한 선호도가 커질수록 두 항만의 가격이 높아지고, 고품질 항만의 가격이 저품질 항만의 가격보다 2배 이상 빠르게 증가하며, 운송비가 커질수록 두 항만의 가격이 함께 작아지나, 저품질 항만의 가격이 고품질 항만의 가격보다 2배 정도 빠르게 감소해 간다. 또한, 고품질 항만 서비스가 상대적으로 높아지면, 고품질 항만의 가격은 올라가지만, 저품질 항만의 가격은 운송비 수준이 높으면 내려간다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.471-474
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• 1998

In this paper, we consider the problem of optimal broadcasting in recursive circulants under multi-port communication model. Recursive circulant G(N, d) that is defined to be a circulant graph with N vertices and jumps of powers of d is a useful interconnection network from the viewpoint of network metrices. Our model assumes that a processor can transmit a message to $\alpha$ neighboring processors simultaneously where $\alpha$ is two or three. For the broadcasting problem, we introduce 3-trees and 4-trees. And then we show that 3-trees and 4-trees are minimum broadcast trees in 2-port model and 3-port model. Using the above results, we show that recursive circulants g(2m, 2) have optimum broadcasting time in 2-port model and 3-port model.

• 오토저널
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• 제15권1호
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• pp.55-66
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• 1993

The characteristics of the flow processes in the cylinder of the two-stroke cycle engines have become the subject of increasing and attention owing to the simplicity and the higher power per unit weight of the two-stroke cycle engine. Among the many factors which influence on the scavenging flow, the port angle is important factor. Hence, four different type models with one inlet-port and two side-ports are studied to show the effect of port angle on the laminar scavenging flow. When the inlet-port axial is relatively larger than the side-port axial angle, it is showed that the fresh charge penetrate into the burned gas and displace it first toward the cylinder head and then toward the exhaust port. When the inlet-port axial angle is much less than the side-port axial angle, the fresh charge through the inlet-port directly move toward the exhaust port. The result showed that the model A may suppress the generation of vortices in the vicinity of inlet and side prots which restrict the sufficient supply of fresh charge and obstruct the perfect displacement of all combustion products.

• 산업경영시스템학회지
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• 제30권3호
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• pp.62-70
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• 2007

This study define the concepts of port logistics service by investigating various elements of port logistics service and grouping them in six attributes using a Data Mining technique. The QFD (Quality Function Deployment) technique is applied to measure the quality of port logistics service, and those results are analyzed. The DMQFD (Quality Function Deployment using Data Mining) model proposed in this study is a model for analyzing of port logistics service quality which is produced by combining those two stages. Using the DMQFD model, the requirements of customer could understand more correctly and systematically, and it could be an alternative tool to accomplish a customer satisfaction.

• 한국항만학회지
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• 제15권1호
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• pp.1-18
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• 2001

The purpose of this study is to explore the nature of the relationship between several factors representing perceived port service quality and the adaptability to the marketing strategy of container terminal. An empirical study was carried out to examine not only the determinants of port service quality using PZB's SERVQUAL model but also its implications to the service marketing strategy. The data investigating the determinants of port service quality were collected from 136 managers from shipping companies by the use of questionnaire method. Factor analysis and t-test were carried out to analyze the data. The results of this study were as follows ; First, Shipping companies perceive the port service quality on two the dimensions of personnel and material aspects. Second, Shipping companies put more emphasis on the reliance of port service quality even though the port authority offers good facilities and materials as parts of port shipping quality. Third, There is a significant relationship between the purchase intention and the customer satisfaction. These findings help not only to formulate service marketing strategy based on service quality but also to be a concept tool to enhance port service quality.

• Journal of Korea Trade
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• 제27권3호
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• pp.65-86
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• 2023

Purpose - As globalization progresses, complexity also increases, and various factors that threaten port functions are emerging. Accordingly, the demand for port security to prevent the crisis and resilience that quickly recovers its original function after the crisis is also increasing in port operations. However, few studies have examined how to ensure the port security and how the resilience affects operation performance of port and sustainability performance as well. So the study aims to find out how port security affects port resilience and port operational performance, and consequently, this two factors affect socioeconomic and environmental sustainability performance respectively and synthetically. Design/methodology - Confirmatory Factor Analysis (CFA) was first performed to determine the validity of the factors of model and hypothesis test was performed using Structural Equation Model (SEM) to analyze the Port Performance Model, which show the perception logic among port security level, port resilience, operation performance, and sustainability performance. In order to empirically analyze this model, total 264 respondents from port security operators, shipping companies in South Korea were surveyed. Findings - As result of SEM, First, port security level positively affected the resilience (H1) and cargo operational performance (H2) but not in both of the sustainability performances (H3, H4). Second, resilience positively affected only cargo operational performance (H5) and socio-economic sustainability performance (H7). Last, cargo operation performance positively affects the both of sustainability performances (H8, H9). Originality/value - It was confirmed that port security could improve cargo operational performance through ensuring port resilience and eventually increase the socio-economic sustainability. Therefore the study implies that careful integration and management of port security, port resilience, and sustainability are required, along with compromise on sustainable development goals in the social, economic, and environmental area among all stakeholders.

• 한국항만경제학회지
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• 제33권4호
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• pp.37-58
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• 2017

설문조사 및 응답자의 지각을 바탕으로 하는 항만선택연구의 암묵적인 가정은 항만선택속성들의 선호크기가 선택행위에 비례적이라는 것이다. 그러나 항만선택 속성들도 직선만이 아닌 비선형적 특성을 갖을 수 있다. 본 연구는 항만선택연구에 성격이 유사한 카노모형을 원용하여 항만선택속성의 비선형적 특성을 확인 하였다. 연구결과 선사의 항만선택속성들중 복합운송연계성과 항만규모 등이 당연특성으로 평가되는 등 여러 속성들이 비선형적 특성으로 평가되었다. 따라서 항만공사와 운영사 등의 항만 서비스제공자들은 선사들의 비선형적 항만선택특성을 반영한 항만운영전략을 구축해야 할 것이다. 본 연구가 항만선택 특성을 탐색적으로 분석하였기 때문에 추후 국내외 항만 및 이해당사자들을 대상으로 한 추가적인 검증연구가 필요하다. 또한 분석 및 전략수립에 활용한 카노모형 및 중요도 선택분석방법도 명확한 특성의 파악과 전략지침의 제시가 가능하도록 개선할 필요가 있다.

• Journal of the Korean Data and Information Science Society
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• 제17권1호
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• pp.87-94
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• 2006

The purpose of this paper is to measure jitter between two server systems. Given 3 empirical models as user and port parallel server types under some conditions of 100 Mbps and optimal CPU temperature suggested by Lee and Kim(2005), our results are shown; jitter was usually measured above 3000 ms in most empirical cases, jumping points were observed around 250 processing traffics, and port parallel model was optimal in our cases.

• 대한전기학회논문지:전력기술부문A
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• 제50권5호
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• pp.248-254
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• 2001

The traction power demand highly varies with time and train positions and the traction load is a large-capacity current at single phase converted from 3-phase power system. Subsequently, each phase current converted from 3-phase power system cannot be maintained in balance any longer and thus the traction load can bring about imbalance in three-phase voltage. Therefore, the exact assessment of voltage unbalance must be carried out preferentially as well as load forecast at stages of designing and planning for electric railway system. The evaluation of unbalance voltage in areas, such as electric railway depots should be a prerequisite with more accuracy. The conventional researches on voltage unbalance have dealt with connection schemes of the transformers used in ac AT-fed electric railroads system and induced formulas to briefly evaluate voltage unbalance in the system(3). These formulas are still being used widely due to their easy applicabilities on voltage unbalance evaluation. Meanwhile, they don't take into account detailed characteristics of ac AT-fed electric railroads system, being founded on some assumptions. Accordingly. accuracy still remains in question. This paper proposes a new method to more effectively estimate voltage unbalance index. In this method, numerous diverted circuits in electric railway depots are categorized in three components and each component is defined as a two-port network model. The equivalent circuit for the entire power supply system is also described into a two-port network model by making parallel and/or series connections of these components. Efficiency and accuracy in voltage unbalance calculation as well can be promoted by simplifying the circuits into two-port network models.