• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.12
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• pp.2340-2352
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• 1994

Under the current IN(Intelligent Network) Architecture, most of their function were performed in SSP(Service Switching point), so the provision or modification of service was limited. To over come these limitation, the structure of 'AIN(Advanced Intelligent Network)' emerged. In this paper, SSP for AIN structure is designed and its performance is evaluated. In other words, the requirements for AIN service implementation are specified on the basis of ITU-T Recommendations. From these requirments and TDX-10 Exchange architecture, the SSP for AIN structure is designed, and its performance is analyzed through the method of simulation and analytical modeling. As a conclusion of this paper, when the system is operated as a standard model, the maximum throughput is 1,270,000 BHCA for Free Phone Service and 1,190,000 BHCA for Credit Call Service. The processors in INS(Interconnection Network Subsystem) are proved to be bottleneck elements. To enhance the performance, several suggestions such as processor and link speedup, and other D_bus service policy are proposed.

• Korean Journal of Construction Engineering and Management
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• v.14 no.3
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• pp.115-122
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• 2013

Construction Standard Productivity Manual (CSPM) has been used for estimating the contract amount of public construction projects. CSPM has been annually either revised and/or newly enacted with high costs. Therefore, This study makes use of CYCLONE, which is a simulation modeling and analysis system specialized in construction operation, to improve the revising and enacting processes of CSPM. This paper presents the CSPM revision module that is an Add-in to Web-CYCLONE. The new module can be effectively used to incorporate the auxiliary tasks and the non-productive tasks into AL-Form operation model. The outputs obtained from the models using he CSPM revision module and from work sampling were compared to verify the usability of the add-in modules. This study verifies that the new module can effectively assist enacting and/or revising CSPM.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.325-330
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• 2006

The container terminal is the unified transportation system which connects between a land transportation and a sea transportation. This system has many subsystems such as ship operation, yard transfer operation, yard storage system, gate operation, and information manage system. This paper presents a method of modeling a simulator with which user can evaluate the efficiency of the equipment and allocation policies in the container terminal. The final purpose is to estimate the efficiency of each equipments and the distribution policies. In a design step in the simulator development. We suggest the Object Oriented method with which the developer can easily design, because the object oriented method has the advantages of reusability and modularity.

• Journal of the Korea Society for Simulation
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• v.27 no.1
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• pp.119-126
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• 2018

This study intended to exploratively testify human error causing factors for railway traffic controller, using AMOS structural equation model. Through literature survey, fatigue and stress as exogenous variable, errors in information process such as cognitive, memory, storage, and execution error as endogenous variable, and accident and incident(near-miss) as dependent variable were set up. Results based on AMOS using 201 railway traffic controllers' questionnaire showed that a clear causality loop like as 'stress ${\rightarrow}$ memory error ${\rightarrow}$ storage error ${\rightarrow}$ incident(near-miss) ${\rightarrow}$ accident' is formed. This result suggests that for the purpose of mitigation of traffic controller's accident, it is so necessary to reduce memory and execution error in the information processing process based on the effective management of stress, as the precedent of them.

• Journal of Navigation and Port Research
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• v.45 no.3
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• pp.155-164
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• 2021

The major factors that threaten port operation are diversie. Coronavirus disease-19, (COVID-19), which has recently disrupted operations worldwide, is one of them. Port operation was completely stopped due to a confirmed coronavirus involving a Russian sailor in Gamcheon Port, Busan, Korea in 2020, resulting port closure due to the infectious disease outbreak. The port is a national infrastructure facility that controls most of Korea's import and export logistics, and it is absolutely necessary to secure resilience against threats such as infectious diseases. However, due to insufficient data, this study was undertaken to determine a cause-effect relationship of infectious diseases during the container port operation using system dynamics. In addition, the port's resilience against infectious diseases was measured in terms of productivity and cargo volume through simulation. The model built via simulation analysis can actually be used to measure the resilience of a port. In the event of an infectious disease outbreak at a port, a quarantine policy scenario can be implemented and the effect compared, thereby improving the resilience.

• Korean Journal of Construction Engineering and Management
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• v.20 no.2
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• pp.68-78
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• 2019

Recently, housing prices have surged, and the government has implemented various regulations, such as finance and taxes. Because of the policy, the nationwide housing price have stabilized, but polarization has occurred. Some argue that regulation can adversely affect the actual demand. Therefore, not only the correlation between market variables but also ripple effect of policy has to be analyzed in policy planning and analysis from a microscopic point of view. In this study, a simulation model was developed by integrating system dynamics for analyzing market structure and agent-based model for modeling decision process of market participants. This research applied the financial regulation and the tax regulation to the model and evaluated the policy effectiveness. This study reveals which feedback dominates according to the policies, which have same purpose. It is because market participants make different decision for each policy. Furthermore, there were other ripple effects not only in the policy target submarket but also in other submarket.

• The Journal of Society for e-Business Studies
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• v.26 no.1
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• pp.67-78
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• 2021

The number of domestic e-commerce transactions has been breaking its own record by an annual average growth rate of over 20% based on volume for the past 5 years. Due to the rapid increase in e-commerce market, retail companies that have difficulty meeting consumers in person are in fierce competition to take the lead in the last mile service, which is the only point of contact with customers. Especially in the delivery area, where competition is most intense, the role of the fulfillment center is very important for service differentiation. It must be capable of fast product preparation ordered by consumers in accordance with the delivery service level. This study focuses on the order picking system for rapid order processing in the fulfillment center as an alternative for companies to gain competitive advantage in the e-commerce market. A mixed integer programming model was developed and implemented to optimize the stock replenishment in order picking facilities. The effectiveness was scientifically and objectively verified by simulation using the actual operation process and data.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.178-178
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• 2022

일반적으로 하천은 상류에서 하류로 흐르지만, 하구에서 일어나는 해안으로부터의 염수의 역류 혹은 상류에서 홍수 발생 시 순간적으로 나타나는 역류 등 주 흐름을 거스르는 흐름이 종종 발생하는데 이는 예상치 못한 피해를 가져올 수 있으므로 최대한 방지해야 한다. 즉, 양방향 흐름이 일어나는 지역을 단방향 흐름으로 바꿔줄 수 있는 수리 구조물의 설치가 필요하다. 역방향 흐름을 제어하는 대표적인 예로는 보가 있는데, 보는 충분한 수위 확보뿐만 아니라 하구에서 역류하는 해수를 방지하는 역할도 한다. 다만, 상류와 하류를 수직적으로 분리함에 따라 물고기의 자유로운 이동을 제한하는 등 생태계를 단절시키는 부작용이 나타날 뿐만 아니라, 최근 정부의 정책에 따라 세종보, 죽산보 등의 보 해체 결정이 이루어지면서 이를 대체할 방안이 필요하다. 따라서 이번 연구에서는 수직적인 구조물이 아닌 수평적인 수리 구조물을 고안함으로써 생태계에 큰 영향을 주지 않으면서 가장 효과적으로 양방향 흐름을 제어할 수 있는 구조물 설계 모형을 탐구해보았다. 구조물 설계 아이디어는 심장의 판막에서 고안하였다. 판막은 특정한 방향성을 갖는 구조로 이루어져 있으면서 혈액의 역류를 방지하는 기관으로, 비슷한 방식으로 하천에도 특정 각도를 갖는 구조물의 설치를 통해 단방향 흐름을 유도할 수 있다고 판단하였다. 실제 하천 규모에서의 실험은 불가능하다고 판단, 전산 유체 프로그램 OpenFOAM을 이용하여 가상 수로의 모델링을 진행하였다. 얇은 판 형태의 흐름 제어 구조물을 수로 측면에 각각 설치 후, 같은 조건에서 정방향 흐름과 역방향 흐름에 대해 각각 시뮬레이션을 진행하였다. 이때, 두 흐름의 하류 유량 크기의 차이를 단방향 흐름을 정량화하는 수치로 산정한다. 시뮬레이션은 구조물과 흐름 방향이 이루는 각도, 구조물의 개수 및 간격, 구조물의 비대칭성 등 여러 가지 조건을 바꿔가면서 진행하고, 유속 분포 및 후류의 크기 등의 수리학적 현상을 파악하여 계산 결과를 분석한다. 분석 결과를 바탕으로 하류의 유량 차이가 가장 크게 나타나는 수리 구조물의 조건을 결정하고, 해당 구조물의 실제 적용 가능 여부를 판단한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.385-386
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• 2022

Currently, global developed countries in shipping and logistics establish smart ports by introducing various digital technologies such as automated terminals and sharing platforms. This means that the importance of efficiency throughout the port by improving resource utilization efficiency and minimizing work idle time is increasing. Therefore, this study proposes a yard truck dispatching method of improving resource utilization efficiency. And we analyze the problems of the existing dispatching rules and develop Y/T dispatching algorithm that comprehensively considers related constraints. In addition, the simulation takes into account the terminal congestion based on the operation data of the Busan New Port, it is conducted using the existing dispatch method and developed Y/T dispatching algorithm. And the operational effects of analysis result are evaluated.

• Korean System Dynamics Review
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• v.10 no.3
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• pp.81-104
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• 2009

이 연구는 청주와 청원의 행정구역 통합에 따른 파급효과를 유량－저량 다이어그램 모형을 구축하여 분석하는 데에 역점을 두며, 제시한 모형은 행정구역 통합에 대한 이론적 고찰과 청주와 청원의 역사적 배경에 토대를 두고, 도시를 구성하는 주요 지표의 인과관계에 기초한다. 첫째, 인구수 측면에서 통합이 이루어질 때의 인구가 분리되어 있을 때의 인구보다 상대적 많이 늘어난다. 분리된 상태에서도 청주와 청원의 인구는 전반적으로 증가 추세를 나타내지만, 통합이 이루어질 경우에는 청원의 인구 유입이 상대적으로 큰 폭으로 늘어나는 경향을 보인다. 둘째, 공무원 수의 측면에서는 통합이 이루어질 때에는 종전에 비해 다소 적은 수의 공무원이 근무하리라고 기대되지만, 그 차이는 미미 하리라고 예측된다. 셋째, 산업체 수와 종업원 수는 인구측면의 시뮬레이션 결과와 유사한 형태를 나타냈다. 통합이 이루어질 경우에는 청주의 산업체수의 변화는 미미하지만, 청원은 산업체 수와 종업원 수에서의 변화가 분리 시나리오에서 보다 큰 증가세를 나타낸다. 넷째, 지방세 수입 측면에서는 통합과 분리 시나리오에 의한 결과 차이가 크지 않았는데, 이는 관련 법령 및 규정에서 통합과 분리에 따른 차이를 조정하고 있기 때문이다. 과거 추세의 측면에서 청주는 지방세 수입 부분이 수렴되고 있는 구조를 나타내고 있으며, 청원은 증가하는 구조를 나타내는데, 청원은 산업체 수와 토지가격의 상승에 따른 세금의 증가로 지방세 규모에서 청주와의 차이가 점차 줄어드리라고 예상한다. 다섯째, 사회기반시설 측면에서 상수도보급률과 도로연장 부문은 통합 시나리오와 분리 시나리오의 결과 차이가 크지는 않았으나, 구축 속도의 측면에서는 통합되는 경우가 청원 지역에 유의미한 효과를 미친다. 왜냐하면 청주에서는 사회기반시설의 상당 부분이 이미 구축되어 있고, 통합 되는 경우에도 사회기반시설측면의 지역개발비가 상당 부분 청원 지역에 우선투자 되도록 통합시 이행결의문이 마련되어 있기 때문이다. 다만, 통합이 이루어지지 않은 경우에도 청원의 사회기반시설 구축은 지속적으로 이루어지리라고 기대된다.