• The KSFM Journal of Fluid Machinery
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• v.7 no.6 s.27
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• pp.15-20
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• 2004

Numerical analysis of the partial admission turbine in the KARI turbopump has been performed. Flow field of the partial admission turbine is intrinsically unsteady and three dimensional. To avoid heavy computational efforts, the frozen rotor method is adopted in computation and compared with the mixing plane approach. The frozen rotor method can represent the variation of a flow field along the circumferential direction of rotor blades, which have the different relative positions to the nozzle with one another. It also illustrates the wake loss mechanism starting from the lip of a nozzle, which is not captured in the mixing plane method. The frozen rotor method has proven to be an efficient tool for the design of a partial admission turbine.

• Korea Science and Art Forum
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• v.35
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• pp.461-471
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• 2018

This study aims to determine the value of the willingness to pay(WTP) admission fees through surveying the level at which visitors to national science museums in Korea are willing to pay for admission fees. The determination helps objectively identify ways to substantially increase admission-based revenues, thereby enhancing managerial efficiency of national science museums. Using the contingent valuation method(CVM), we analyzed the WTP for admission fees of 250 visitors to Gwacheon National Science Museum. The statistical analysis revealed that the average amount of WTP was far higher than the current admission fees(4,000 won for adults and 2,000 won for children and adolescents). WTP of questionnaire respondents was normally distributed at the mean of 8,447 won for adult admission and 6,535 won for non-adult admission to Gwacheon National Science Museum. This result can be used as basic evidence to redetermine admission fees of national science museums and ultimately improve financial vitality.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.861-866
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• 2004

A numerical flow analysis has been performed on the partial admission turbine of KARI turbopump to support the aerodynamic and structural dynamic assessments. The flow-field in a partial admission turbine is essentially three dimensional and unsteady because of a tip clearance and a finite number of nozzles. Therefore the mixing plane method is generally not appropriate. To avoid heavy computational load due to an unsteady three dimensional calculation, a frozen rotor method was implemented in steady calculation. It adopted a rotating frame in the grid block of a rotor blade by adding some source terms in governing equations. Its results were compared with a mixing plane method. The frozen rotor method can detect the variation of flow-field dependent upon the blade's circumferential position relative to the nozzle. It gives a idea of wake loss mechanism starting from the lip of a nozzle. This wake loss was assumed to be one of the most difficult issues in turbine designers. Thus, the frozen rotor approach has proven to be an efficient and robust tool in design of a partial admission turbine.

• Korean Journal of Comparative Education
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• v.18 no.4
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• pp.113-139
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• 2008

The purpose of this study is to analyze the operating case of admission officer system of colleges and universities in USA, and to deduce its implications to Korean colleges and universities. In order to accomplish the purpose of this study, following methodologies were adopted: review on the related literatures, statistical data, and previous studies concerning admission officers of colleges and universities in USA, and in-depth interview with them. Historical and cultural background of university admission system of USA was analyzed. Case study on USA colleges and universities was divided with four parts such as determining factors of admission and admission methods, organization for admission affairs and its number of persons, work of admission officer and admission process, and cost of admission and salary. Implications to Korean colleges and universities were presented with three points such as overall implication, implication on materials for admission process, and implication on managing system of admission. Based on the analysis, discussion and implications, the conclusion and further suggestion of this study are as follows: First, actual authority of admission should be grant to admission officer. Second, not only non-curricular factors but also scholastic factors should be emphasized in role of admission officer. Third, education and training about work of admission officer and unification of criteria for admission should be held. Fourth, admission officers with various occupation background are needed. Fifth, work of admission officers should be extended to various work concerning university entrance. Sixth, cross-checking on marks of over two admission officers is needed. Seventh, in order to stabilize admission process, status of admission officer should be stabilized. Eighth, part-time admission officers are need to employ in season of admission. Ninth, authority of weighting high schools should be grant to admission officers in long term perspective.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.10
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• pp.2376-2394
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• 2013

In order to ensure both of the whole system capacity and users QoS requirements in heterogeneous wireless networks, admission control mechanism should be well designed. In this paper, Multi-agent Q-learning based Admission Control Mechanism (MQACM) is proposed to handle new and handoff call access problems appropriately. MQACM obtains the optimal decision policy by using an improved form of single-agent Q-learning method, Multi-agent Q-learning (MQ) method. MQ method is creatively introduced to solve the admission control problem in heterogeneous wireless networks in this paper. In addition, different priorities are allocated to multiple services aiming to make MQACM perform even well in congested network scenarios. It can be observed from both analysis and simulation results that our proposed method not only outperforms existing schemes with enhanced call blocking probability and handoff dropping probability performance, but also has better network universality and stability than other schemes.

• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.65-74
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• 2003

In this Paper, we propose a downlink service admission strategy that considers users QoS requirements by using a novel service quality prediction index for multi-service WCDMA mobile systems. The Proposed downlink service admission strategy is obtained by computing average received Power of each service, assuming a relative other-cell interference factor. With the proposed method we obtain a downlink service admission region where users of different services properly can be admitted. And adding the fairness at the proposed downiinh service admission strategy, we Propose another downlink service admission strategy. In the numerical examples, the downlink service admission region with fairness and the downlink service admission region without fairness of voice service and data services are obtained by proposed downlink service admission strategies, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.9A
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• pp.2184-2196
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• 1998

Admission control is one of the most important congestion control mechanism to be executed at the call set up phase by regulating traffic into a network in a preventive way. An efficient QOS evaluation or bandwidth estimation method is required for call admission to be decided in real time. In this paper, we spropose a computtionally simple approximation method of estimating cell loss probability and mean cell delay for admission control of both delay sensitive and loss sensitive calls. Mixed input queueing system, where a new call combines with the existing traffic, is used as a queueing model for QOS estimation. Also traffic parameters are suggested to characterize both a new call and existing traffic. Aggregate traffic is approximated by a renewal process with these traffic parameters and then mean delay and cell loss probability are detemined using appropriate approximation formulas. The accuracy of this approximation approach is examined by comparing their results with exact analysis or simulation results of vrious mixed unput queueing systems. Based on this QOS estimation method, call admission control scheme which is traffic independent and computable in yeal time are proposed.

• Journal of Acupuncture Research
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• v.28 no.5
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• pp.77-86
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• 2011

Objective : This study was designed to evaluate the effect of bee venom pharmacopuncture therapy in patients with FBSS(failed back surgery syndrome). Methods : We investigated 30 cases of patients with FBSS, who had been treated from October 2010 to July 2011. We divided patients into two groups : group I was treated by acupuncture therapy only, and group II was treated by bee venom pharmacopuncture therapy and general acupuncture. We measured the efficacy of treatments using the numerical rating scale(NRS) and grade and straight leg raising(SLR) test. Results : 1. The treatment method for group II was more effective than that of group I in reducing the NRS score on the fifteenth day after admission but there was no statistically significant difference between the results of two groups on the fifth day after admission and the tenth day after admission. 2. The treatment method for group II was more effective than that of group I in NRS improvement rate from its admission day to the fifth day after admission and from the tenth day after admission to the fifteenth day after admission but there was no statistically significant difference between the performance of two groups from the fifth day after admission to the tenth day after admission. 3. Group II had a higher grade improvement rate from the seventh day after admission to the fifteenth day after admission than group I but no statistically significant difference was observed between the results of two groups from its admission day to the seventh day after admission. 4. In SLR test improvement rate the treatments applied to group II was more effective than those applied to group I. Conclusion : The results of this study suggest that bee venom pharmacopuncture therapy is effective in reducing pain for patients with FBSS. Further clinical research is needed to verify these results and findings.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.593-603
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• 1997

Connection admission decision in ATM networks requires decision made in real time using fast algorithm. It is difficult to construct a model of the multiplexed traffic and thus, approximation of the traffic load is necessary. In this paper, we propose a measurement-based dynamic CAC(Connection admission Control) in ATM(Asynchronous Transfer Mode) networks, which observes current traffic by the moving window and set the window size to the value which is computed from the measured cell loss amount. It is based on the measurements of the traffic load over an admission period that is load enough to reflect the current traffic behavior instead of analytic modeling. And, the dynamic reallocation of bandwidth for each class leads to effective bandwidth utilization. The performance of proposed method is analyzed through computer simulation. The performance of proposed method is analyzed by using SIMAN simulation package and FORTRAN language. As can be seen in the simulation result, cell loss performance and bandwidth utilization have been increased.

• Journal of the Institute of Convergence Signal Processing
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• v.1 no.2
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• pp.97-104
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• 2000

Effective call admission control is desirable to control an ATM traffics. It should provide high fairness and utilization for different kinds of services during call admission. Complete bandwidth sharing method is efficient for utilization of bandwidth but not efficient for fairness of call admission. Complete bandwidth partitioning method is efficient for fairness but not efficient for utilization. We propose a new CST(Complete Sharing with Threshold) algorithm using threshold on a total link to improve fairness and utilization.