• 산업공학
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• 제3권1호
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• pp.13-20
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• 1990

The application of human-factor concept in developing a complex weapon system is important for system engineer to determine the system performance and reliability. This paper describes the evaluation procedure of human factors in the X-system wherein the evaluation result provides a better performance than the previous model in operatability and maintainability. The criteria used for the evaluation of a design adequacy of the X-system are based on the military human-factor standards.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.128.1-128
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• 2001

A propulsion system apparatus is needed for a railroad vehicle to test and estimate propulsion performance. The electrical inertia simulator to facilitate the development and testing of propulsion systems, is presented in this paper. It is based on a vector-controlled Induction motor drive supplied from the AC mains through a double PWM converter that provides desirable features such as hi-directional power folw, nearly unity power factor and low harmonic factor at the Ac mains. A theoretical analysis is first presented, followed by a detailed simulation study to assess the overall system performance under dynamic conditions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2131-2136
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• 2008

The characteristics of heat transfer and pressure drop in an offset strip fin heat exchanger was studied with a steady-state three dimensional numerical model. Flow Reynolds number $Re_{dh}$ ranged from 10 to 3500 and Prandtl number Pr ranged from 0.7 to 50. The dimensionless performance factors, i.e. 'the pumping power factor F' and 'the heat transfer performance factor J' were analyzed and obtained a relationship between them. Finally, the prediction of F and J factors was generalized for different Prandtl numbers.

• Journal of Power Electronics
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• 제6권2호
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• pp.121-130
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• 2006

This paper presents the performance and efficiency of a drive system incorporating a switched-reluctance motor (SRM) with input power factor correction (PFC). The proposed system consists of a PFC, bi-directional converter, an inverter, and a SRM operating as based voltage source drives (VSD). First, theoretical analysis is made for each identified mode of operation in the drive system. This is followed by comparing the performance of the SRM drive system with and without a PFC circuit. The losses are also calculated for both systems and overall efficiency. Experimental results are presented to prove the theoretical analysis.

• 통상정보연구
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• 제12권1호
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• pp.299-325
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• 2010

The purpose of this empirical study is an index to usage of export assistance programs for korean small-medium exporters. Build around the index make an analysis of SMEs internal or exterior factors have an effect on export at present or in future export performance and the relative importance. Based on 128 surveys form korean SMEs experienced export assistance programs, 8 hypotheses, which are set up each factor, were verified through the practical analysis. The main result of hypothesis drawn by empirical study are as follows : The more SMEs use the programs, the more high export performance at present and in future. Export competitive factor reject at present export performance, but it will affect future export performance. A size of the firm in the characteristics of SEMs will affect export performance. Export rate of own brand will not affect performance. Another factors show adoption partly concerned hypothesis. Classified exterior factors of SMEs, a intensity of market competition shows adoption partly concerned hypothesis. Market growth rate will affect export performance at present and future strongly. Finally the usage of assistance programs will affect between a consumption goods and an industrial goods differently. From this study we found if we want to develop the export assistance programs that can actually in phases help the SEMs.

• 한국IT서비스학회지
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• 제5권2호
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• pp.59-78
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• 2006

This research is to suggest the factor which is effecting on the information system audit fidelity in the perspective of audit procurer, to develop the measure to evaluate it, to investigate the audit performance and project performance for comparison the audit fidelity between the audit teams. As the analysis results, we found that the audit service factors can be divided to the expert knowledge of auditor and the project attributes itself. It means these factors are the major measures for the audit fidelity. In this research, the hypothesis of this study model is verified throughout the factor and corelation analysis, and the structured equation model is applied. Analysis results show that all relations between the factors are significant statistically. The audit service factors has an effect on audit fidelity. Also the information system audit fidelity can be affect on the project performance, audit performance and customer satisfaction. So, in conclusion, we need to judge closely the audit service factors affecting the audit fidelity for the enhancement of the project performance, audit performance and customer satisfaction.

• International journal of advanced smart convergence
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• 제9권2호
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• pp.68-75
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• 2020

Non-orthogonal multiple access (NOMA) has gained the significant attention in the fifth generation (5G) mobile communication, which enables the advanced smart convergence of the artificial intelligence (AI), the internet of things (IoT), and many of the state-of-the-art technologies. Recently, correlated superposition coding (SC) has been proposed in NOMA, to achieve the near-perfect successive interference cancellation (SIC) bit-error rate (BER) performance for the stronger channel users, and to mitigate the severe BER performance degradation for the weaker channel users. In the correlated SC NOMA scheme, the stronger channel user BER performance is even better than the perfect SIC BER performance, for some range of the power allocation factor. However, such excessively good BER performance is not good for the user-fairness, i.e., the more power to the weaker channel user and the less power to the stronger channel user, because the excessively good BER performance of the stronger channel user results in the worse BER performance of the weaker channel user. Therefore, in this paper, we propose the power splitting to establish the user-fairness between both users. First, we derive a closed-form expression for the power splitting factor. Then it is shown that in terms of BER performance, the user-fairness is established between the two users. In result, the power splitting scheme could be considered in correlated SC NOMA for the user-fairness.

• 대한기계학회논문집B
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• 제27권3호
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• pp.389-397
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• 2003

Effect of tip leakage flow on through flow and performance of a centrifugal compressor impeller was numerically studied using CFX-TASC flow. Seven different tip clearances were used to consider the influence of tip clearance on performance. Secondary flow and loss factor were evaluated to understand the loss mechanism inside the impeller due to tip leakage flow. The calculated results were circumferentially averaged along the passage and at the impeller exit for quantitative discussion. Tip clearance effect on Performance could be decomposed into inviscid and viscous components using one dimensional equation. The inviscid component is related with the specific work reduction and the viscous component is related with the additional entropy generation. Two components affected Performance equally. while efficiency drop was mainly influenced by viscous loss. Performance and efficiency drop due to tip clearance were proportional to the ratio of tip clearance to exit blade height. A simple model suggested in the present study predict performance and efficiency drop quite successfully.

• 대한안전경영과학회지
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• 제10권1호
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• pp.107-116
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• 2008

Nowadays, BSC presented by alpan is observed by many enterprises and is being operated gradually. BSC includes non-financial factor as well as financial factor in performance assessment and it is a tool that will be able to evaluate even strategy of long-term view. In point of performance management, BSC brings in relief importance on non-financial performance as well as financial performance and it shares with viewpoint of 4 things of financial viewpoint, customer viewpoint, internal process view point, learning and growth viewpoint. then these make an array with vision and strategy of organization by causal relationship, it presented necessity of performance control on organization as center on KPI of inner of each viewpoint. Thus, study on measures and control of management performance is progressed actively and is accomplishing much development. This study is aimed at calculation of weight that is able to reflect its importance about AHP on KPI of each viewpoint. The purpose of this study is to present desirable performance measurement model and to give a weight in consideration of working-level character.

• 한국유체기계학회 논문집
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• 제13권4호
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• pp.37-43
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• 2010

The purpose of this study is not only to investigate the effects of air layer in the turbine chamber on the performance and internal flow of the cross-flow turbine, but also to suggest a newly developed air supply method. Field test is performed in order to measure the output power of the turbine by a new air supply method. CFD analysis on the performance and internal flow of the turbine is conducted by an unsteady state calculation using a two-phase flow model in order to embody the air layer effect on the turbine performance effectively. The result shows that air layer effect on the performance of the turbine is considerable. The air layer located in the turbine runner passage plays the role of preventing a shock loss at the runner axis and suppressing a recirculation flow in the runner. The location of air suction hole on the chamber wall is very important factor for the performance improvement. Moreover, the ratio between air from suction pipe and water from turbine inlet is also significant factor of the turbine performance.