• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.6B
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• pp.895-900
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• 2010

As the diverse telecommunication services have been developed, network designers need to prevent congestion which may be caused by properties of timecorrelation and burstiness, and unpredictable statistical fluctuation of traffic streams. This paper considers the leaky bucket scheme with combined control of arrival and token rates, in which the arrival rate and the token generation interval are controlled according to the queue length. By using the embedded Markov chain and the supplementary variable methods, we obtain the queue length distribution as well as the loss probability and the mean waiting time.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.5
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• pp.62-70
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• 2016

Ensuring walkability in a city where pedestrians and vehicles coexist is an issue of critical importance. The relative relationship between vehicle transit and walkability improvements complicates the evaluation of walkability, which thus necessitates the formation of a quantitative standard by which a methodological measurement of walkability can be achieved inside the pedestrian network. Therefore, a model is determined whereby quantitative indices such as, but not limited to, experiences of accessibility, mobility, and convenience within the network are estimated. This research proposes the integration of space syntax theory and the logit path choice model in the evaluation of walkability. Space syntax theory assesses adequacy of the constructed pedestrian network through calculation of the link integration value, while the logit model estimates its safety, mobility, and accessibility using probability. The advantage of the integrated model hence lies in its ability to sufficiently reflect such evaluation measures as the integration value, mobility convenience, accessibility potential, and safety experienced by the demand in a quantitative manner through probability computation. In this research, the Dial Algorithm is used to arrive at a solution to the logit model. This process requires that the physical distance of the pedestrian network and the perceptive distance of space syntax theory be made equivalent. In this, the research makes use of network expansion to reflect wait times. The evaluation index calculated through the integrated model is reviewed and using the results of this sample network, the applicability of the model is assessed.

• Journal of Korean Society of Transportation
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• v.19 no.1
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• pp.89-99
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• 2001

The conventional studies on equilibrium network design problem(ENDP) with fixed travel demand models assume that the future OD travel demand might not be changed even if the structure and the capacity of the network are improved. But this fixed demand assumption may loose its validity in the long-range network design because OD travel demand actually shifts with the network service level. Thus, it is desirable to involve the variable travel demand which is determined endogenously in the model in the optimal network design. In this paper a hi-level model formulation and solution procedure for ENDP with variable travel demand are presented. Firstly It is considered how to measure the net user benefits to be derived from the improved in link capacities, and the equilibrium network design problem considered here is to maximize the increase of net user benefit which results from a set of lift capacity enhancements within the budget constraints, while the OD travel demands and link travel times are obtained by solving the lower level network equilibrium problem with variable demand. And secondly sensitivity analysis is carried out to find the links to which the network equilibrium flow pattern is the most sensitive. Finally numerical example with simple network is carried out to test the validity of the model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.4
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• pp.509-518
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• 1993

Protocol conversion is to resolve the imcompatibility between networks so that users on different protocols can communicate with each other. This paper designs a formal model, EPN , to increase its modeling power and analyze conversion protocol and proposes a conversion algorithm using it. The conversion algorithm has two capabilities : synchronization and automatic error recovery function. Therefore burden of protocol converter design will be reduced, automatic protocol converter design can be possible and implementation for half-gateway will be easy.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.657-660
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• 2000

최근 재사용성에 근간을 둔 컴포넌트 기반 소프트웨어(Component-Based Software : CBS) 기술의 실현에 따라 이와 관련된 유지보수 의사결정의 내용도 변화하여 새로운 연구 과제로 등장하고 있다. 이에 본 연구는 컴포넌트 기반 소프트웨어 유지보수와 관련된 의사결정의 이론적 근거를 탐색하고 컴포넌트 평가 및 선택을 위한 모형 개발을 목적으로 한다. 모형 설계에는 평가 기준의 체계를 수립하고 적절한 평가 기법의 선택 및 적용이 포함된다. 평가 기준 구성을 위하여 CBS 유지보수의 특성을 고려한 다차원적 접근법에 의한 계층적 체계화를 시도하였으며, 일부 상호 종속적 관계를 나타내는 요소들에 대하여는 네트워크 관계를 나타내는 모듈로 포함시켰다. 체계화된 평가 기준에 따른 의사결정 대안의 평가 기법으로 주관적 판단의 계량화에 적절하다고 판단되는 계층분석과정(Analytic Hierarchy Process) 기법 및 네트워크분석과정(Analytic Network Process) 기법을 선정하고 적절한 예를 들어 모형 적용의 이해를 돕고자 하였다.

• 한국벤처창업학회:학술대회논문집
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• 2020.06a
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• pp.141-147
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• 2020

최근 중소기업연구원 연구자료에 의하면 우리나라 중소벤처기업의 혁신 수준은 OECD 최하위 수준이며, 네트워크 기반의 협력체계가 필요하다고 발표하였다. 또한, 최근의 혁신 행동 관련 연구를 살펴보면 내적 혁신 행동에 대한 연구는 많으나, 외부 네트워크 혁신 행동과 연동한 연구는 미진하였다. 따라서 본 연구의 목적은 CEO 변혁적 리더십이 조직 공정성을 기반으로 내적 외적 혁신 행동을 실행함에 있어서 유연적 조직 문화의 조절 효과가 사업성과에 미치는 영향에 대해서 알아보고자 한다. 이론적 고찰을 통해 중소벤처기업 성과모형, CEO 변혁적 리더십, 내적 혁신 행동, 외적 혁신 행동, 조직 공정성, 유연적 조직문화, 사업성과에 대해서 알아보았다. Chrisman 등(1998)의 중소벤처기업 성과모형은 ①기업가(entrepreneur), ②산업구조(industry structure), ③사업전략(business strategy), ④자원(resources), ⑤조직구조(organization structure, processes and systems) 등 5가지를 제시하였다. 본 연구에서는 Chrisman 등(1998)의 벤처기업 성과모형 NVP = f(E, IS, BS, R, OS)을 적용하여 연구 모형을 설계하고 실증 검증하였다. 향후 중소벤처기업 성과모형으로서 직원들의 미래전망과 자부심 향상에 본 연구가 시사점을 제공할 뿐만 아니라 중소벤처기업 경쟁력 강화를 위한 기업 혁신 행동 컨설팅 연구에도 기여할 수 있을 것으로 판단된다.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.129-139
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• 2010

This study proposes a model for measuring the connectivity of nodes in road networks. The connectivity index between two nodes is characterized by the number of routes, degree of circuitousness, design speed, and route capacity between the nodes. The connectivity index of a node is then defined as the weighted average of the connectivity indexes between the node and other nodes under consideration. The weighting factor between two nodes is determined by the travel demand and distance between them. The application of the model to a toy network shows that it reasonably well quantifies the level of connectivity of nodes in the network. If flow of rail networks can be measured in the same scale as that of road networks and the capacity of rail links can be estimated, the model proposed in this paper could be applied to intermodal transportation networks as well.

• Journal of Korean Society of Transportation
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• v.26 no.6
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• pp.93-101
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• 2008

With a spread of mobile devices, the growing trend of integrating wireless communications technologies into transportation systems is advanced. In particular, vehicular ad hoc networks (VANETs) enable vehicles to share traffic information that they have through intervehicle communications. This research focused on the design of an integrated transportation and communication simulation framework to build an environment that is more realistic than previous studies developed for studying VANETs. Developing a VANET-based information model, this research designed an integrated transportation and communication simulation framework in which these independent simulation tools not supporting High Level Architecture (HLA) were tightly coupled and finely synchronized. As a case study, a VANET-based traffic information system was demonstrated based on a real road network and real traffic data. The experiment results showed that the simulation framework was well integrated. The simulation framework designed in this study is expected to contribute to developing the environment to experiment a wide range of VANET applications.

• The Korean Journal of Archival Studies
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• no.56
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• pp.183-212
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• 2018

The study aimed at exploring a direction of development of the conceptual model for organizing public digital records. First, it started with reviewing the possibility of item-oriented records and archival organization, then analyzed RIC-CM developed by ICA EGAD. Second, it investigated the hierarchies of the classes and descriptive information applied to public digital records, as well as showed the necessities of transition from paper-based model to digital-based one. Based on these, it studied to seek possibilities for organizing public digital records not by record groups but by items. Finally, this study proposed the direction of development of the next generation conceptual model for organizing public digital records.

• Journal of the Korean Society for Railway
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• v.11 no.6
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• pp.581-587
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• 2008

This paper presents a railway network design problem (RNDP), which can be formulated as a bi-level program. In bi-level program upper level program is to minimize total travel cost including the construction cost of the railway facilities, whilst lower one describes the railway route choice behavior of passengers. We also propose a heuristic method for solving the program because it is a kind of NP-hard problem. From two numerical railway examples, we confirm that the RNDP and its algorithm produce a reasonable solution and that it is applicable to real world.