• 전자통신동향분석
• /
• 제10권2호통권36호
• /
• pp.25-32
• /
• 1995

본 연구는 정보 통신 투자가 경제 전반에 미치는 효과를 분석함으로써 초고속 정보 통신망 투자의 경제적 효율성을 검토하고자 했다. 정보 통신 산업에 대한 투자효과는 1980년 이후 계속된 투자인데 이 투자로 인해 1990년의 최종수요를 충족하기 위한 생산활동 과정에서 1990년 총소요 자원비용 금액 중 1조 5,567억원의 자원 절감 효과를 발생시킨 것으로 계산되었다.

• 전자통신동향분석
• /
• 제5권4호
• /
• pp.3-11
• /
• 1990

본고에서는 현재 ISO/IEC JTC1에서 활발히 추진되고 있는 국제기능표준 제정 활동과 JTC1/SGFS에서 작성된 기술문서 TR10000을 기본으로 프로파일과 분류법, 상세분류사항, 적합성 요구사항 그리고 프로파일구조에 대하여 기술하고 있다. TR10000은 국제기능표준의 형식, 내용구조 및 분류체계를 정의함으로써 국제기능표준안 작성을 위한 지침을 제공한다.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1990년도 추계학술대회
• /
• pp.57-60
• /
• 1990

• Tribology and Lubricants
• /
• 제6권2호
• /
• pp.68-75
• /
• 1990

The metal-dithiophosphates as lubricant additives for reducing friction and wear, increasing load-carrying capacity and a antioxidant are very important as new additives developed in these day. The synthetic results of Metal-DTPs were described. The wear test was conducted with 4-Ball machine and wear debris were analyzed by ferrography. The tribological performances of Metal-DTPs were compared with Zn-DTP.

• The Korean Journal of Ecology
• /
• 제14권1호
• /
• pp.49-61
• /
• 1991

Phytosociological invesstigation of the forest vegetation was carried out in Oinrodo island at the period from June 5th 1990 to June 10th 1990 by Braun-Blanquet's method. The forest vegetation was classified into 10 communities, Castanopsis cuspidata var. sieboldii, Machilus thunsbergii, Neolitsea sericea, Quercus glauca-Actinodaphne lancifolia, Pinus thunbergii, Chamaecyparis obtusa, Cryptomeria japonica, Quercus acutissima, Quercus variabilis, and Carpinus coreana community. Based on the classification of communities, the actual vegetation map was drawn in 1 : 50,000 scale.

• 대한기계학회논문집
• /
• 제14권4호
• /
• pp.953-959
• /
• 1990

본 연구에서는 임의의 순간에서 난류유동장의 난류구조를 해석하기 위하여 Lumley의 특성 에디 분배법을 이용하였다. 이때 난류구조의 해석은 비등질성의 K-L 전개와 등질성의 푸리에 전개로 표현하여 그 수렴성, 레이놀즈 수의 영향 등 여러가지 특성을 연구하였다. 본 연구에서 선정한 비등질성 난류유동장은 Chambers등이 연구 한 랜덤력을 갖는 Burgers 방정식을 수치적으로 풀어서 얻었다. 이와 같은 난류유동 장을 K-L전개와 푸리에 전개로 표현할 때에 수렴성은 레이놀즈 수가 서로 다르고 또한 전개항의 수가 다를 때에 RMS 오차를 가지고 비교하였다.여기서 푸리에 전개 계수 들은 Galerkin 방법으로 구하였다.

• Journal of the Korean Statistical Society
• /
• 제19권2호
• /
• pp.176-181
• /
• 1990

Sung [1990] presented an analogue of the classical Cramer-Rao inequality for median-unbiased estimators with continuous multivariate densities depending upon a vector parameter. In the process, diffusivity, a new dispersion measure relevant to median-unbiased estimators, was defined to be a function of median-unbiased estimator's density height. In this paper we shall elaborate these ideas by defining a second kind of diffusivity and discuss the role of model-unbiasedness in median-unbiased estimation in connection with this seconde kind of diffusivity. In addition, median-unbiased estimation will be compared to mean-unbiased estimation.

• Communications for Statistical Applications and Methods
• /
• 제15권3호
• /
• pp.421-427
• /
• 2008

This paper deals with the problem of testing for the existence of change in mean and estimating the change-point when the data are from the exponential distributions. The likelihood ratio test statistic and Gombay and Horvath (1990) test statistic are compared in a power study when there exists one change-point in the exponential means. Also the change-point estimator using the likelihood ratio and the change-point estimators based on Gombay and Horvath (1990) statistic are compared for their detecting capability via simulation.

• 대한원격탐사학회지
• /
• 제6권2호
• /
• pp.153-164
• /
• 1990

A statistical correlation between cloud thickness and brightness is shown by regression analysis using the least-square method. Cloud thicknesses are obtained from radiosonde observation. Brightness values are obtained from GMS visible channel. Regression analyses are preformed on both thickness data used in conjunction with brightness data for summer season. The results are shown by the regression curve relating thickness and brightness accounting for 79% of variance. And the relationship between thickness and precipitable water in the cloud layers is analyzed. The thickness shows a positive correlation with precipitable water in cloudy layers.

• Bulletin of the Korean Chemical Society
• /
• 제11권3호
• /
• pp.248-250
• /
• 1990

Dichloro and ethylenediamine rhodium(III) complexes of a flexible $N_2O_2$-type tetradentate ligand, ethylenediamine-N,N'-di- -butyric acid(eddb), have been prepared. Both s-cis- and uns-cis geometrical isomers have been yielded in the $[Rh(eddb)Cl_2]-\;and\;[Rh(eddb)(en)]^+$ complexes. Ir, pmr, and electronic absorption spectra are used to characterize the complexes obtained in this work.