• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.36-46
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• 2000

The performance improvement and emission reduction in a turbocharged D.I. diesel engine was studied experimentally in this paper. The system of intake port, fuel injection and turbochager are very important factors which have influence on the engine performance and exhaust emission because the properties in the injected fuel depend on the combustion characteristics. Through these experiments it can be expected to meet performance and emission by optimizing the main parameters; the swirl ratio of intake port, fuel injection system and turbocharger. The swirl ratio of intake port was modified by hand-working and measured by impulse swirl meter. Through this steady flow test, we knew that the increase of swirl ratio is decreasing the mean flow coefficient, whereas the gulf factor is increasing. And the optimum results of engine performance and emission are as follows; the swirl ratio is 2.43, injection timing is BTDC 13。 CA, compression ratio is 16, combustion bowl is re-entrant 5$^{\circ}$, nozzle hole diameter is $\Phi$0.28＊6, turbocharger is GT40 model which are compressor A/R 0.58 AND turbine A/R 1.19.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.12-13
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• 2002

The performance improvement of 40Gbit/s soliton transmission system employing nonlinear optical loop mirror (NOLM) as all-optical regenerative repeater is investigated. The switching characteristic of NOLM is optimized using our design strategies. By inserting the optical repeater where the eye-penalty of the transmitted signal becomes 1 ㏈, we achieve the improvement of 0.3㏈ eye-penalty resulting in further 480km transmission distance.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.888-891
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• 1996

The objective of a mixed H$_{2}$/H$_{\infty}$ controller of active suspension system is to achieve not only the general performance improvement(H$_{2}$) but also the worst case disturbance rejection(H$_{\infty}$). In this paper, a mixed H$_{2}$/H$_{\infty}$ controller for an active suspension system, comparing the performance with that of an H$_{2}$ controller and of an H$_{\infty}$ controller.ler.EX> controller.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1130-1135
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• 2001

This paper investigated the dynamic performance of HDD disk-spindle system to reduce disk fluttering. Rocking frequencies of the disk-spindle system and radial NRRO are measured to escape the ball defect frequencies and to determine the relative optimal position of the disk in the motor. It was found that disk fluttering was reduced by increasing disk thickness, inserting viscoelastic material between the disk and the spacer and decreasing the gap between the disk and the base.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.541-544
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• 2003

In this paper, we analyzed a physical layer of W-CDMA system and a performance of a downlink of W-CDMA system by using the space-time code by computer simulation over the ITU-R realistic channel model. From the results of the simulation, we note that the increase of multi-path components affects the improvement of the system performance because of the effect of the RAKE receiver.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.8
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• pp.1437-1443
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• 2000

This paper considers a channel estimation technique in a wireless local area network (WLAN) system with complementary code keying (CCK) signaling over multipath fading channels. This scheme uses the maximum correlator output of RAKE receiver for the extraction of the channel parameters. The performance of the proposed detection technique is compared with that of a noncoherent detection technique, and a significant improvement of performance is observed in terms of the bit error probability.

• Convergence Security Journal
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• v.16 no.1
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• pp.13-21
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• 2016

At the present moment when around 60 years have passed after the introduction of private security, there are security instructor and protection specialist guard as government official recognition qualification. This study discussed problems of secondary performance test system among qualification certification items which have been implement ed as government official recognition qualification since 2013. Current qualification certification for protection specialist guard is composed of primary academic test and secondary performance test. Since it is estimated that it is high time to increase clients' satisfaction and public reliability through strict qualification certification for protection specialist guard. Following improvement plans are intended to suggest. First, it is a plan to divide and diversify difficulties of performance test evaluation events. Second, it is a plan to diversify evaluation criteria of performance test. Third, it is a plan to make criteria for selecting specialized performance test evaluation committee. Fourth, it is a new plan of exclusion system to avoid any relation between performance test evaluation committee and applicants. In this respect, institutional improvement should be followed in order to improve specialty of qualification certification of performance test system for protection specialist guard.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.1
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• pp.33-40
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• 2023

With the development of supercomputing technology and hardware technology, numerical computation methods are also being advanced. Accordingly, improved weather prediction becomes possible. In this paper, we propose to apply the LAPACK(Linear Algebra PACKage) BLAS(Basic Linear Algebra Subprograms) library to the linear algebraic numerical computation part within the source code to improve the performance of the cumulative parametric code, Unicon(A Unified Convection Scheme), which is included in SCAM(Single-Columns Atmospheric Model, simplified version of CESM(Community Earth System Model)) and performs standby operations. In order to analyze this, an overall execution structure diagram of SCAM was presented and a test was conducted in the relevant execution environment. Compared to the existing source code, the SCOPY function achieved 0.4053% performance improvement, the DSCAL function 0.7812%, and the DDOT function 0.0469%, and all of them showed a 0.8537% performance improvement. This means that the LAPACK BLAS application method, a library for high-density linear algebra operations proposed in this paper, can improve performance without additional hardware intervention in the same CPU environment.

• Journal of Korea Technology Innovation Society
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• v.1 no.3
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• pp.299-312
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• 1998

This paper explores the possibility of improving R&D management system through researchers' satisfaction analysis. The relationship between job satisfaction and performance has traditionally been one of the engaging topics in organization psychology. However, the research results of the past showed the relatively low level of correlation between satisfaction and performance at the individual level. In contrast to these past research results, recent research results on this relationship at the organizational level revealed the higher correlation between these two factors, The present study extends this 'satisfaction and performance' hypothesis to the development and improvement of R&D management system. That is, we used the results of researchers' satisfaction analysis to devise appropriate criteria for the design and implementation of more effective R&D management systems. This paper seeks to show that we can make fruitful use of researchers' satisfaction analysis in order to choose a more effective one among alternative R&D management systems.

• Knowledge Management Research
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• v.12 no.5
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• pp.71-87
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• 2011

This study focuses on influencing factors of TAM on personality, subjective norm and then examines the relationship between influencing factors such as KMS usage and system performance. The survey was collected from KMS users by e-mail and on-line questionnaire. Finally, 206 questionnaires were chosen for the analysis of data. It was analyzed by SPSS and AMOS for the frequency analysis, reliability analysis, CFA(Confirmatory Factor Analysis) and SEM(Structural Equation Modeling). The results were as follows. First, subjective norm is found to be especially important to KMS usage. Second, Extraversion positively moderated the relationship between subjective norm and perceived usefulness. Third, KMS usage is significant to personal performance such as knowledge growth, decision making and the ability of problem solving. This study proposed that the usage of Knowledge Management System positively contributes to the improvement of personal performance.