• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.1
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• pp.119-130
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• 1996

This paper is the part I of the full study about improved structure of fully interconnected ATM switch to develop the small sized switch element and practical implemention of switch network. This part I paper describes about proposed switch structure, performance evaluations and some of considerations to practical implementation. The proposed structure is constructed of two step buffering scheme in a filtered multiplexer. First step buffering is carried out by small sized dedicated buffers located at each input port. And second step buffering is provided by a large sized common buffer at the output port. To control bursty traffic, we use speed up factor in multiplexing and priority polling according to the levels of buffer occupancy. Proposed structure was evaluated by computer simulation with two evaluation points. One is comparision of multiplexing discipline between hub polling and priority polling. The ogher is overall which should be considered to improve the practical implementation.

• Electronics and Telecommunications Trends
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• v.32 no.5
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• pp.65-73
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• 2017

A holography technique optically reconstructs a three-dimensional object in space to provide a natural sense of depth and volume to the observer, thereby providing an ultimate 3D image capable of solving the problem of "vergence-accommodation conflict" occurring in a conventional stereoscopic imaging system. In this paper, we present a technical framework for measuring the performance and evaluating the quality of a holographic display, which enables a quantitative measurement of the optical and physical properties that affect the performance and quality of a holographic display. In addition, we provide the trend regarding standardization related to holographic display measurements. Although this trend has barely started, research activities related to holographic display measurements and quality evaluations are expected to grow in the near future.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.489-492
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• 2002

The objective of the present study were to measure the viscosities of non-Newtonian fluids by the transient flow concept in a capillary tube and to apply to hemodynamic studies and pump performance evaluations. The developed capillary tube viscometer could be used to measure the viscosities of the non-Newtonian fluids for a wide range of the shear rate by a run of experiment in a very short time interval. The measured viscosities of water and blood fur different shear rates were good agreement with those of the well established data. The measured viscosities for muddy water varied with the shear rates.

• Journal of electromagnetic engineering and science
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• v.7 no.1
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• pp.35-41
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• 2007

An alternative solution to the problem of obtaining acceptable performances on a fading channel is the diversity technique, which is widely used to combat the fading effects of time-variant channels. The symbol error probability of M-ary DPSK (MDPSK), PSK (MPSK) and QAM (MQAM) systems using 2 branches from the branch with the largest signal-to-noise ratio(SNR) at the output of L-branch selection combining(SC), i.e., SC2 in frequency-nonselective slow Nakagami fading channels with an additive white Gaussian noise(AWGN) is derived theoretically. These performance evaluations allow designers to determine M-ary modulation methods against Nakagami fading channels.

• Journal of the Ergonomics Society of Korea
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• v.21 no.3
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• pp.25-34
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• 2002

The road sign in dynamic traffic system is an important element which affects on human cognitive performance on driving. Web-based vision system simulator was developed to examine the cognition time of the road sign in dynamic environment. This experiment the cognition time of the road sign in dynamic environment. This experiment was designed in with-subject design with two factors: vehicle speed and the amount of information of the traffic sign. It measured the cognition time of the road sign through two evaluation methods: the subjective test with vision system simulator and computational cognitive model. In these two evaluations of human cognitive performance under the dynamic traffic environment, it demonstrated that subject's cognition time was affected by both the amount of information of traffic sign and driving speed.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1083-1088
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• 2001

To do performance evaluations about inorganic permanent form mixed in admixture(fly ash, silica fume) and after placed concrete, it is examined reinforcement materials in the permanent form from shear strength, bond strength and flexural strength tests. In this study, permanent form was inserted with reinforcement metal fitting is strength-tested in several method. The result of this study is belows. ⑴ In bond strength test, Most specimens are satisfied with criterion-6 kgf/$cm^{2}$ ⑵ Irrelative with the inserted metal fitting's shape, unevenness and aggregate, Permanent form and after placed concrete have good condition in the shear strength test. ⑶ In flexural test, there is no drop out of permanent form. Most cracks are located in nearby the strain point

• Journal of Electrical Engineering and Technology
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• v.6 no.4
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• pp.459-465
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• 2011

A phasor estimation algorithm based on the least square curve fitting technique for the distorted secondary current due to current transformer (CT) saturation is proposed. The mathematical form of the secondary current during CT saturation is represented as the scaled primary current with magnetizing current. The information on the scaled primary current is estimated using the least square technique, with the measured secondary current in the saturated section. The proposed method can estimate the phasor of a fundamental frequency component during the saturated period. The performance of the algorithm is validated under various fault and CT conditions using a C400 CT model. A series of performance evaluations shows that the proposed phasor estimation algorithm can estimate the phasor of the fundamental frequency component with high accuracy, regardless of fault conditions and CT characteristics.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11C
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• pp.1045-1052
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• 2005

The symbol error probability of M-ary PSK (MPSK) and QAM (MQAM) systems using the branch with the largest signal-to-noise ratio (SNR) at the output of L-branch selection combining (SC) in frequency-nonselective slow Nakagami fading channels with an additive white Gaussian noise (AWGN) is derived theoretically For integer values of the Nakagami fading parameter m, the general formula for evaluating symbol error rate (SER) of MPSK signals in the independent branch diversity system comprises numerical analyses with the integral-form expressions. An exact closed-form SER performance of MQAM signals under the effect of SC diversity via numerical integration is presented. These performance evaluations allow designers to determine M-ary modulation methods for Nakagami fading channels.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.05a
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• pp.163-168
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• 2002

The road sign in dynamic traffic system is an important element which affects on human cognitive performance on driving. Web-based vision system simulator was developed to examine the cognition time of the road sign in dynamic environment. This experiment was designed in within-subject design with two factors; vehicle speed and the amount of information of the traffic sign. It measured the cognition time of the road sign through two evaluation methods; the subjective test with vision system simulator and computational cognitive model. In these two evaluations of human cognitive performance under the dynamic traffic environment, it demonstrated that subject's cognition time was affected by both the amount of information of traffic sign and driving speed.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.110-115
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• 2001

Today, effective utilization of sophisticated networks greatly influences the activities of a business, making performance evaluations of computer network systems a necessity, We have developed a special computer network simulator capable of automatically generating a model based on data accumulated by a network analyzer to guide the user in selecting ideal parameters. The simulator was developed to provide user-friendly analysis for engineers involved in the actual network design. This paper gives an overview of the simulator and describes an example application of evaluating a network design that anticipates the future increase in traffic for a company introducing voice over frame relay (VoFR) into a wide area network (WAW).