• Journal of the Korean Statistical Society
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• 제33권3호
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• pp.323-337
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• 2004

This article coined a general class of estimators for various measures in normal population when some' a priori' or guessed value of standard deviation a is available in addition to sample information. The class of estimators is primarily defined for a function of standard deviation. An unbiased estimator and the minimum mean squared error estimator are worked out and the suggested class of estimators is compared with these classical estimators. Numerical computations in terms of percent relative efficiency and absolute relative bias established the merits of the proposed class of estimators especially for small samples. Simulation study confirms the excellence of the proposed class of estimators. The beauty of this article lies in estimation of various measures like standard deviation, variance, Fisher information, precision of sample mean, process capability index $C_{p}$, fourth moment about mean, mean deviation about mean etc. as particular cases of the proposed class of estimators.

• The Korean Journal of Ecology
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• 제21권5_1호
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• pp.427-433
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• 1998

The standing crop and net production were estimated in Moojaechi on Mt. Jungjok. By using the decay model of organic carbon, absolute year of bog peat was calculated. Pollen analysis to bog peat revealed vegetational history and climate change around Moojaechi. The time required for amount of the accumulated peat in the bog was estimated in terms of the balance of the accumulation and decay of organic carbon of the deposit peat. Absolute year of the peat surveyed in this study was about 314 years. Pollen of Pinus was predominant in all the pollen zone, Geamineae and Cyperaceae increased in lower pollen zone while Pinus in upper pollen zone. This showes that climate of the past was probably more humid than that of present. In addition, middle pollen zone showed warming trend which is suggested by high pollen concentration of Quercus, Juglans, Carpinus and Corylus. It suggests that overall environment and vegetation were changed from warmer and more humid to dry condition in Moojaechi and it is considered as the course of boggy ground formation by retrogressive successions.

• 대한화학회지
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• 제57권3호
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• pp.370-376
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• 2013

A back propagation artificial neural network model with one hidden layer is established to correlate the liquid-liquid equilibrium data of hydrocarbon-water systems. The model has four inputs and two outputs. The network is systematically trained with 48 data points in the range of 283.15 to 405.37K. Statistical analyses show that the optimised neural network model can yield excellent agreement with experimental data(the average absolute deviations equal to 0.037% and 0.0012% for the correlated mole fractions of hydrocarbon in two coexisting liquid phases respectively). The comparison in terms of average absolute deviation between the correlated mole fractions for each binary system and literature results indicates that the artificial neural network model gives far better results. This study also shows that artificial neural network model could be developed for the phase equilibria for a family of hydrocarbon-water binaries.

• Geomechanics and Engineering
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• 제32권1호
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• pp.21-34
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• 2023

In order to analyze the effect of the cyclic lateral loading on the response of a pile-soil system, a full-scale single steel pile was subjected to one-way cyclic loading. The test pile was driven into a bi-layered soil consisting of a normally consolidated saturated clay overlying a silty sandy layer, the site being submerged by water up to one meter above the mudline in order to reproduce the conditions of an offshore pile foundation. The aim of this paper is to present the main results of interpretation of the cyclic lateral tests in terms of pile deflections, bending moment, and cyclic P-Y curves. From these latter an absolute secant reaction modulus E_AS,N was derived and a simple calculation model of the test single pile is proposed based on this modulus. Two applications of the proposed model are carried out, one with a 2D finite element modelling, and the second with a load transfer curves-based method.

• 한국식품영양과학회지
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• 제24권6호
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• pp.892-900
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• 1995

본 연구대상자들은 열량공급 영양소인 탄수화물 : 단백질 : 지방으로 부터 각각 전체 열량의 63% : 14% : 24%를 공급받아 한국인의 권장비인 65 : 15 : 20에 근사한 값을 보여주고 있다. 이러한 이상적인 섭취양상은 sucrose/starch ratio나 P/S ratio cholesterol 등에서도 바람직한 섭취수준을 보여주고 있어 본 조사대상자는 식이를 통한 고혈압 위험인자를 비교적 적게 갖고 있는 것으로 나타났다. 단, 섭취량이 위험수준 이상 보다 높을 것으로 기대되는 나트륨의 섭취량은 조리과정에서 첨가되는 식염의 양을 측정하지 못하여 그 위함의 심각성을 도출하지 못했다. 영양소 섭취의 식품공급원의 순위와 개인간의 변이식품의 순위는 일반적으로 모든 영양소(열량, 단백질, 지방, 나트륨, 칼륨)에서 크게 다른 것으로 나타나 영양소의 주된 공급식품을 중심으로 빈도조사법의 설문지를 작성할 경우 개인간의 섭취량의 차이를 찾아내는데 크게 실패할 가능성을 보여주고 있다. 단, cholesterol의 경우는 제한된 식품에 의존해서 공급받는 것으로 나타나 공급식품과 변이식품의 순위가 크게 차이 나지않아 빈도조사법 설문지 개발시 주된 공급식품의 섭취빈도 조사만으로도 개인간의 변이를 충분히 반영할 수 있는 것으로 나타났다. 그러므로 질병과의 관련성을 규명하기 위해 식이조사에서 식품섭취 빈도법을 이용하여 설문지를 개발할 경우 주된 급원식품만을 포함시킨다면 개인간의 섭취량의 차이를 도출해 낼 수 없으나, 포함되는 식품항목의 금원식품 뿐 아니라 변이식품도 포함시키는 것이 개인간의 영양소 섭취의 차이를 찾아낼 수 있는 좋은 방법임을 본 연구결과는 시사하고 있다. 본 연구는 고혈압의 식이성 위험인자가 되는 영양소를 중심으로 개인간의 섭취량의 차이를 규명하기 위한 식이조사를 한다는 전제하에 조사에 사용될 식품섭취 빈도법의 설문지 개발시 포함시켜야 할 식품항목의 타당성을 공급식품과 변이식품의 순위 분석을 통해 관찰해 봄으로써 조사표 작성의 기초자료를 제공하고자 하였다. 앞으로 고혈압 이오의 다른 질병인 경우에도 이와같은 연구가 진행되어 각각의 질병연구에 적절한 조사표 작성의 기초자료들이 제공되어야 역학연구에서 식이조사의 효율성을 기대할 수 있을 것이다.

• 인문언어
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• 제7집
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• pp.123-155
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• 2005

This paper concerns different forms of poetic thinking, each of which attempts to investigating truth of being on the ground of its idiosyncratic feature. The horizon evoked via these practices, however, is the Absolute where any plausibility of communication be fundamentally blocked off. Poetry, for instance, relinquishes its semantic auto-referentiality in order to be expressive of something unsayable. Poetic diction, coming-into-being, and sound with no meaning are those three expressive modes that I will examine in terms of the so-called "poetic thinking."

• 천문학회지
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• 제17권1호
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• pp.15-22
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• 1984

The transverse velocities of the gravitational lens system (galaxy plus a 'disturbing star') and their dependences on unkown properties of the source and the deflecting object are discussed. We have derived an analytic expression for the transverse velocity in terms of the velocities of the light source, the gravitational lensing galaxy and the 'disturbing star', and the observer. The results are then further applied to an estimate of the expectation value of the absolute transverse velocity and of the probable time scales of flux changes of the double QSO 0957+561A, B.

• 대한수학회지
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• 제41권5호
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• pp.875-882
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• 2004

Let (M,g) be a compact m dimensional Einstein manifold with smooth boundary. Let $\Delta$$_{p}$,B be the realization of the p form valued Laplacian with a suitable boundary condition B. Let Spec($\Delta$$_{p}$,B) be the spectrum where each eigenvalue is repeated according to multiplicity. We show that certain geometric properties of the boundary may be spectrally characterized in terms of this data where we fix the Einstein constant.ant.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.81-87
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• 1993

In this paper robust stability conditions are obtained for linear dynamical systems under structured nonlinear time-varying perturbations, using absolute stability theory and the concept of dissipative systems. The conditions are expressed in terms of solutions to linear matrix inequality(LMI). Based on this result, a synthesis methodology is developed for robust feedback controllers with worst-case H$_{2}$ perforrmance via convex optimization and LMI formulation.

• 대한산업공학회지
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• 제15권2호
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• pp.65-75
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• 1989

A general software reliability model is developed, which includes the Jelinski-Moranda model, the Goel-Okumoto model, the Shanthikumar model and the Ross model as special cases. In each of above models estimators of the software failure rate and the number of remaining errors are presented and compared in terms of the expected absolute error loss and the expected squared error loss by a Monte Carlo simulation.