• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.2
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• pp.139-151
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• 1997

An ATM switching system may be designed so that communications between processors of its control part can be performed via its switching network rather than a separate inter-processor communications (IPC) network. In such a system, there should be interfaces to convent IPC traffic from message format to cell format and vice versa, that is, mechanisms to perform the SAR (Segmentation And Reassembly) sublayer functions. In this paper, we concern the cell reassembly mechanism among them, mainly focussed on buffer management schemes. We consider a few alternatives to implement cell reassembly function block, namely, separated buffering, reserved buffering and shared buffering in this paper. In case of separated and reserved buffering, we employ a continuous time Markov chain for the performance evaluation of cell reassembly mechanism, judicially defining the states of the mechanism. Performance measures such as measage loss probability, mean number of message queued in buffer and average reassembly delay are obtianed in closed forms. In case of shared buffering, we compare the alternatives for implementing cell reassembly function block using simulation because it is almost impossible to analyze the mechanism of shared buffering by analytical modeling. Some illustrations are given for the performance analysis of the alternatives to implement cell reassembly function block.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.455-459
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• 2008

This study defines the Next Generation System(NGS) built by domestic financial businesses and classifies their architecture into two typical types according to the duration of the project and the relative cost of IT investment in the short term: the Big Bang approach and the Phase approach. Herein, we study the two approaches as alternatives in developing the Next Generation System, and derive the factors that are to be considered in the evaluation of the two alternatives for financial businesses. The set of standards for the choice between the two models are grouped into categories that constitute performance evaluation for IT - Cost, Performance and Risk. We drill down further into each category to second and third subordinate levels to derive detailed selection criteria. Based on the criteria drawn from the study, we conduct a survey with information system planners, IT managers and specialists at financial companies who are currently planning, developing or have completed a Next Generation System. Survey results are analyzed using the AHP methodology to compare and understand the different approach in the implementation of NGS for financial business.

• Journal of the Korea Society for Simulation
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• v.10 no.3
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• pp.47-58
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• 2001

Evaluation of Freeway Congestion Management Using Mesoscopic Traffic Simulator A mesoscopic simulation study to measure the effects of trip generation caused by rampant expansion of residential area around the Kyungbu corridor has been conducted. Some alternatives, which seem to be judgememtally plausible and technically feasible to mitigate such congestion, have been carefully examined and evaluated by the simulation model called INTEGRATION. Alternatives are mostly network improvements. Banpo IC dedicated ramp construction (A1), Seocho IC TSM based weaving elimination (A2), dedicated local and express separation over Seocho-Yangjae segment (A3), Heonleung IC (A4) and Daewang If installations (A5), Pangyo IC improvement (A6), Baikhyun IC (A7) and Dongbaek IC installations (A8) along with Shingal-Pangyo segment capacity addition (A9). The most capital intensive ones are A9, A5, and A4 in that order. A1, A6, A7, and A8 are short in distance but they are also capital intensive and need some construction periods. The least capital driven alternatives are h2 and A3, the h2 is easier to do, but A3 needs traffic diversion scheme during construction. The A1, A7, and A8 have been identified cost effective in terms of speed increase and travel time saving. Along with these results, some limitations and future research agenda regarding simulation have also been presented.

• Journal of Korean Society of Transportation
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• v.5 no.1
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• pp.25-31
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• 1987

This article shows that, in the logit models, the(conditional) expected utility of the decision makers choosing an alternative is invariant across all alternatives. This property of the logit model implies that the logit model can not explain the distributional wealfare effects of a transportation policy (or transportation investment) among different alternatives, and thus the logit model is not proper for evaluating transportation policy in equity aspects.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2000.11a
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• pp.259-277
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• 2000

In this paper, we suggest theoretical grounds on the problem of R&D portfolio with different option premiums utilizing the Real Options Model, which has received intensified attention as the method of assessment of R&D project with high risk. Even though there have been many studies focused on the evaluation of option value of single project from technology valuation's perspective. there are few study on the portfolio of multiple technology investment by option value using. This paper bears practical importance by showing simple examples with the option value of investment alternatives and the valuation of related risk, the construction of optimum portfolio in technology investment alternatives.

• Journal of Korean Society for Quality Management
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• v.12 no.1
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• pp.17-30
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• 1984

A computer method is developed for group technology layout and its simulation analysis. The method is composed of three phases: Phase I sorts the parts by its similar production routes and forms part families. Phase II plots the layout by machine cell and evaluates the group layout alternatives by the total process time analysis and the part travel distance evaluation analysis. Phase III also evaluates the alternatives by simulation analysis using SIMAN simulation software. All the computer programs are developed with BASIC except SIMAN simulation.

• Water for future
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• v.25 no.1
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• pp.83-92
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• 1992

Selection of the best operation rule among a set of alternatives for a multipurpose reservoir system operation requires to evaluate many minor criteria I n addition to the major objectives assessed to the system, These problems are sufficiently complex and difficult that they are beyond heuristic decision rules and experiences in case several noncommensurable multiple criteria are included in the evaluation. With the assistance of multicriterion decision analysis techniques, it is possible to select the best one among various alternatives by systematically comparing and ranking the alternatives with respect to the criteria of choice. Evaluation criteria for multipurpose reservoir system operating rules were identified and defined, and the multicriterion decision analysis techniques were applied to evaluate the fore developed operating rules of the existing Chungju multipurpose project according to the identified nine multiple criteria. The application result shows that the methodology is very efficient to select the best operation alternative among a finite number of operating rules with many evaluation criteria for a large scale reservoir system operation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.1
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• pp.103-112
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• 2018

To improve current transportation service, a new Seoul Metropolitan Transportation Administration (Seoul MTA), backed by Korean central government, is on the way of being established. This paper tries to answer questions such as 'What is the best type of organizational formation of the upcoming institute to deliver better, seamless transportation service?' and 'What is the most suitable scope of work of the upcoming institute to achieve the goal?' A group decision making process, a kind of AHP (Analytic Hierarchy Process) was adopted to measure the experts' preferences of alternatives in quantitative scale measurement. To evaluate the alternatives, five evaluation criteria were selected. Among them, it is revealed that 'Improvement of the transportation service' and 'Political & Administrative power to make it happen' are the two most important evaluation criteria over what types or operating costs of the administrations are. When the five evaluation criteria are applied onto the group of alternatives, it yields that a stand-alone organization, which should be independent from upper-level government body, should have an integrated and sole authority on the area-wide transportation system management.

• Journal of Ocean Engineering and Technology
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• v.14 no.2
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• pp.117-120
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• 2000

In the Step of preliminary ship design a designer should decide a economic ship. The economic ship has the least building cost to a annual freight amount satisfying a given design condition That is RFR is minimum among alternatives.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1B
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• pp.41-51
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• 2012

Sometimes, there exist many alternatives for doing a SOC project. However, the limitation of the fund requires the determination of investment priority for the alternatives. This may be performed according to the degree of importance of individual alternatives. Especially, the river improvement project at the downstream of dams has complex and various values and this characteristics make it difficult decision-maker to do reasonable determination. This study aims to determine an investment priority of 33 alternatives in the river improvement project at the downstream of dams using PROMETHEE method which has advantages in determining the priority. In this study, we determined evaluation criteria and attributes by considering the functions and objectives of the river improvement project at the downstream of dams. The eigenvector method in AHP was used to estimate the relative importance of evaluation criterion. Based on the estimation, we determined investment priority of 33 alternatives by PROMETHEE method and the priority of alternatives was derived in the order of Juam regulation dam, Unmun dam, Yongdam dam and so on. The results of this study could provide a reasonable standard to the decision-maker for the determination of investment priority of alternatives.