• Proceedings of the Korea Contents Association Conference
• /
• 2004.05a
• /
• pp.234-240
• /
• 2004

Now that the e-commerce users are explosively increasing, there is always followed by a sharp increase in load from the e-commerce system and the heavy traffic on the network, where leads to the delayed service for the client's request. The natural consequences contain decreasing customer satisfaction and weakening the business's competitive position in markets. Therefore, we'll need to study the e-commerce system in due consideration of the operational efficiency and response speed. This study includes a design of e-commerce system, with a hierarchical structure based on the local server, which has the capability of caching necessary to distribute the system load, makes a proposal concerning a split web-cache algorithm devoted to the local web server to finally give an analysis of the performance through the appropriate trial.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1996.05a
• /
• pp.158-161
• /
• 1996

The static charges are generated by streaming electrification phenomena in insulating oil flowing by force for the purpose of cooling at the internal of Ultra-high power transformer. In this thesis, their elimination method was studied. In this paper the effect of Additive on the electric conductivity of Insulating oil is studied. The variation of electric conductivity disappear when Additive is molten in insulating oil BTA(Benzotriazole) appear more variation of electric conductivity than that of SP-S10(Sorbitan mono-stearate). But the variation is not enough to decrease streaming electrification of insulating oil($\sigma$>10$\^$-12/[S/cm]).

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.10a
• /
• pp.434-439
• /
• 2000

In this paper, in order to study the geometric factor effect of a circular hole near a crack tip in a semi-infinite plate, the Dimensionless Stress Intensity Factor, $F(=\frac K {\sigma {\sqrt{\pi a}}})$ is analyzed at the crack tip using a two Dimensional Boundary Element Method (BEM) program which is known as superior in Fracture Mechanics. Kelvin's solution was used as a fundamental solution in BEM analysis and displacement extrapolation method was used to determine Stress Intensity Factor.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2003.11a
• /
• pp.248-258
• /
• 2003

Finite element computations were carried out to study the indentation by rigid cone with half-angle of $70.3^{\circ}$ for 72 different combinations of elasto-plastic properties that cover the wide range of mechanical parameters of common engineering solid materials. The dimensional analysis and representative strain concept were used in the analysis. It was shown that for the same representative strain value, the loading curvature C can be formulated under two different forms, which are based on two alternative dimensionless functions. The present study's one is simpler than the other previously found by other authors using the similar approach. For a wide range of material's parameters, the hardness-modulus ratio should be a parabolic function of ${\sigma}E$, rather than a power law function earlier proposed.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.20 no.2
• /
• pp.37-42
• /
• 1983

This paper presents a procedure within the framework of linear potential theory for predicting the lateral drifting forces on a cylinder floating on the free surface of a finite depth water. The disturbance of a regular incident wave caused by the presence of the floating body is represented by the sum of the diffracted and radiated wave potentials, which are determined by using Green's theorem. The lateral drifting forces are calculated by use of momentum theorem, and the scattered waves are expressed in their asymptotic forms. The computed lateral drifting forces on a Lewis form cylinder(b/T=1.25, $\sigma$=0.95) for water depth to draft ratio of 5.0 are compared with the Kyozuka's experimental results for a deep water, and found to be in good agreement. The water depth effects on drifting forces of the same model are also calculated.

• Journal of the Korean Chemical Society
• /
• v.8 no.1
• /
• pp.30-32
• /
• 1964

H. Eyring등의 액체의 구조에 관한 이론에 따라서 액체 사염화탄소의 partition function을 정하였다. 이 Partition function 에 쓰인 parameter $E_s,\;{\sigma},\;{\theta},\;V_s$ 등은 액체 안의 고체와 같은 분자의 고요한 값으로 새로운 방법$^{(4)}$으로 그 값들을 정하였다. 이렇게 정해진 Partition function을 써서 액체 사염화탄소의 몰부피, 증기압, 한계점, 증발엔트로피 및 표면장력 등을 계산하였다. 계산치와 실측치를 비교한 결과 몰부피와 증기압, 엔트로피의 값은 거의 일치하였다. 표면장력 또한 실험치와 좋은 일치를 보여주는 값을 얻었다.

• ETRI Journal
• /
• v.29 no.1
• /
• pp.70-78
• /
• 2007

A new low-voltage CMOS interface circuit with digital output for piezo-resistive transducer is proposed. An input current sensing configuration is used to detect change in piezo-resistance due to applied pressure and to allow low-voltage circuit operation. A simple 1-bit first-order delta-sigma modulator is used to produce an output digital bitstream. The proposed interface circuit is realized in a 0.35 ${\mu}m$ CMOS technology and draws less than 200 ${\mu}A$ from a single 1.5 V power supply voltage. Simulation results show that the circuit can achieve an equivalent output resolution of 9.67 bits with less than 0.23% non-linearity error.

• Electronics and Telecommunications Trends
• /
• v.17 no.4 s.76
• /
• pp.16-28
• /
• 2002

전세계적인 경기 침체에도 불구하고 벤처 캐피탈로부터 수억 달러의 투자 자금을 끌어 모아 2001년 한해 큰 주목을 받았던 메트로 이더넷 서비스 사업자들이 최근 주춤하고 있다. 메트로 이더넷 서비스 시장의 선두 주자였던 Yipes Communications가 2002년 3월 추가적인 투자 자금 모집 실패 및 재무 유동성 악화로 인하여 미국 법원에 파산 보호를 신청한 것을 비롯해, 이보다 앞서 또 다른 메트로 이더넷 서비스 사업자인 Sigma Networks도 불과 창업 1년 만에 문을 닫고 말았기 때문이다. 이로 인해 일각에서는 이제 메트로 이더넷 서비스 비즈니스 모델을 다시 제고해야 할 시점이라면서, 메트로 이더넷 서비스 사업자들도 결국 과거 CLEC들과 같은 전철을 밟게 되지는 않을까 우려하는 목소리가 높다. 이에 본 고에서는 메트로 이더넷 서비스 비즈니스 모델을 현재 시점에서 재조명하고, 최근 시장 현황 그리고 앞으로의 발전 전망에 대하여 간략하게 살펴보았다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1999.05a
• /
• pp.147-152
• /
• 1999

The strengthening of a metal matrix composite(MMC) by the shape memory effect(SME) of dispersed TiNi particles was theoretically studied. An analytical model was constructed for the prediction of the average residual stress(<$\sigma$>/sub/m) on the base of the Eshelby's equivalent inclusion method. The analysis was performed on the TiNi particle/Al metal matrix composites with varying volume fractions and prestrains of the particle. The residual stress caused by the shape memory of predeformed fillers has been predicted to contribute significantly to the strengthening of this composite.

• Journal of the Chungcheong Mathematical Society
• /
• v.33 no.1
• /
• pp.147-156
• /
• 2020

The functional equation related to a distance measure f(pr, qs) + f(ps, qr) = M(r, s)f(p, q) + M(p, q)f(r, s) can be generalized a sum form functional equation as follows $${\frac{1}{n}}{\sum\limits_{i=0}^{n-1}}f(P{\cdot}{\sigma}_i(Q))=M(Q)f(P)+M(P)f(Q)$$ where f, g is information measures, P and Q are the set of n-array discrete measure, and σ_i is a permutation for each i = 0, 1, ⋯, n-1. In this paper, we obtain the hyperstability of the above type functional equation.