• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.395-402
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• 2003

Characteristics of base isolators including frictional and hysteretic types may be described by Bouc-Wen model. A probabilistic optimum design method of the base isolation system using Bouc-Wen model is presented in this paper. For optimum design, the objective function and constraints are derived based on the stochastic responses of the system. As a numerical example, the optimum design problem of a three-story base isolated shear type structure is formulated and solved by the sequential quadratic programming method.

• 한국군사과학기술학회지
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• 제10권3호
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• pp.208-216
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• 2007

As the propellant mass is being accelerated out of the gun chamber along with the projectile, a continuous pressure gradient exists between the end of chamber and the base of the projectile. For this reason, the base pressure-travel curve is very important to design a conventional gun barrel in the interior ballistics, but it is not obtained briefly by empirical or theoretical method. In this paper, a simple relation between chamber pressure and base pressure was determined by the factor of base pressure(Cb) obtained from the experimental method. The simple relation gives a reasonable prediction for the reduction of pressure between the breech and the base of projectile owing to the axial gradient in the gun tube. The predictions have been validated by the infrared screen sensor and the PRODAS(PROjectile Design and Analysis System) for interior ballistic systems. Therefore, the base pressure-travel curve could be calculated from the chamber pressure measured by piezoelectric sensor. The base pressure-travel curve obtained from the simple relation offers initial information to gun barrel designer and is used for calculation of muzzle velocity.

• 지능정보연구
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• 제7권2호
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• pp.65-81
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• 2001

본 논문에서는 전문가 시스템 개발에 있어서 체계적인 규칙추출을 위하여 지식베이스 구축에 관한 분석/설계단계까지를 5개 단계로 세분화하여 지식획득과정을 강화하였다. 또한 각 단계별로 지식공학자가 수행해야 하는 프로세스와 각 프로세스별로 지식공학자가 실질적인 작업을 통해 결과를 산출하는 태스크를 정형화하였다. 본 논문에서는 제안한 체계적인 규칙추출 방법론을 이용하여 아군 화력자산의 파괴율을 고려하고, 지휘관의 의도에 부합하는 아군 화력자산을 배분하는 STAFS 전문가시스템의 지식베이스 모듈 개발에 관한 연구를 수행하였다.

• 정보통신설비학회논문지
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• 제10권2호
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• pp.80-85
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• 2011

In this paper, I propose flexible base point used for a BTC(Block Truncation Coding). Halftoning images are used for printer by reducing the number of pixel depth. During over 20 years, many researches have been studied to apply this techniques to image compression. BTC algorithms are the compression methods using digital halftoning technique about images. In the BTC algorithm, an image block is divided into higher and lower domain compared with the mean of block. then the MAX and MIN representative values are evaluated by calculating the mean of higher and lower domain respectively. At a result, an image block(for example 88 size) is compressed into 64bits pixel representation and 16 bits of the MAX and MIN. And they also have been tried to sustain the image quality high after compression. In this paper, I found that there is some marginal possibility to enhance the image quality by adjusting the base point(generally mean of block) of existing algorithms.

• 펄프종이기술
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• 제44권1호
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• pp.24-30
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• 2012

This study was carried out in order to analyze a repletion possibility about color change of base paper after elevated heat exposure when wooden fillers were added. Fillers may reduce production cost because its price is usually inexpensive than pulp with higher bulkiness. Wooden fillers have lower density than inorganic fillers, so they may increase bulk more than inorganic fillers. Never the less wooden fillers have disadvantage of yellow color by heat exposure, so the addition level should be carefully controlled. Brightness and whiteness changes after elevated heat exposure depending on coating weight were analyzed. With wooden fillers addition, breaking length and surface strength decreased but bulkiness increased. As the exposure time of elevated heat increased the coating paper with wooden fillers addition had higher brightness and whiteness values than those of inorganic fillers.

• 한국전기전자재료학회논문지
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• 제20권5호
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• pp.403-409
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• 2007

In this paper, effects of the trench angle($\theta$) on the breakdown voltage according to the process parameters of p-base region and doping concentrations of n-drift region in a Trench Gate IGBT (TIGBT) device were analyzed by computer simulation. Processes parameters used by variables are diffusion temperature, implant dose of p-base region and doping concentration of n-drift region, and aspects of breakdown voltage change with change of each parameter were examined. As diffusion temperature of the p-base region increases, depth of the p-base region increases and effect of the diffusion temperature on the breakdown voltage is very low in the case of small trench angle($45\;^{\circ}$) but that is increases 134.8 % in the case of high trench angle($90\;^{\circ}$). Moreover, as implant dose of the p-base region increases, doping concentration of the p-base region increases and effect of the implant dose on the breakdown voltage is very low in the case of small trench angle($45\;^{\circ}$) but that is increases 232.1 % in the case of high trench angle($90\;^{\circ}$). These phenomenons is why electric field concentrated in the trench is distributed to the p-base region as the diffusion temperature and implant dose of the p-base increase. However, effect of the doping concentration variation in the n-drift region on the breakdown voltage varies just 9.3 % as trench angle increases from $45\;^{\circ}$ to $90\;^{\circ}$. This is why magnitude of electric field concentrated in the trench changes, but direction of that doesn't change. In this paper, respective reasons were analyzed through the electric field concentration analysis by computer simulation.

• Structural Engineering and Mechanics
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• 제30권3호
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• pp.351-368
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• 2008

The purpose of this paper is to propose a simple analysis method of axial deformation of base-isolation rubber bearings in a building subjected to earthquake loading and present its applicability to the analysis of the bound of the aspect ratio of base-isolated buildings. The base shear coefficient is introduced as a key parameter for the bound analysis. The bound of the aspect ratio of base-isolated buildings is analyzed based on the relationship of the following four quantities; (i) ultimate state of the tensile stress of rubber bearings based on a proposed simple recursive analysis for seismic loading, (ii) ultimate state of drift of the base-isolation story for seismic loading, (iii) ultimate state of the axial compressive stress of rubber bearings under dead loads, (iv) prediction of the overturning moment at the base for seismic loading. In particular, a new recursive analysis method of axial deformation of rubber bearings is presented taking into account the nonlinear tensile behavior of rubber bearings and it is shown that the relaxation of the constraint on the ultimate state of the tensile stress of rubber bearings increases the limiting aspect ratio.

• Tribology and Lubricants
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• 제31권1호
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• pp.28-34
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• 2015

This paper addresses the problems of using anti-freeze lubricants for different machines that must function at extremely low temperatures during winter operation in the Republic of Sakha (Yakutia). We discuss the possibility of obtaining anti-freeze base oils from Talakan crude oil, an area with major oil and gas deposits of the Republic of Sakha, and also provide the trade and technological classification of Talakan crude oil. We propose two different schemes for processing Talakan crude oil: the fuel scheme (obtaining light and heavy fractions as a fuel oil) and the base oil scheme (obtaining light fractions and base oils). We investigate the influence of pour point depressants on alkyl-methacrylate base on the low-temperature properties of the fractions obtained from Talakan crude oil and Korean base oils, and establish the optimal concentration of pour point depressants. We compare the properties of these fractions with the low-temperature properties of Korean base oils and find that the commercial oil "Ravenol 0W-40" provides optimistic results. We obtain oil with a pour point of minus $50^{\circ}C$ and a viscosity index greater than 100. The Design of Experiment was used to establish the optimum composition of the pour point depressants and the base oil S-8 to obtain lubricant oil with a kinematic viscosity of 17 cSt, viscosity index of 208, and a pour point of minus $64^{\circ}C$.

• 한국수학교육학회지시리즈A:수학교육
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• 제50권1호
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• pp.1-12
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• 2011

It is the aim of this paper to study the target problem solving process in reference to the base problem. We observed closely how students solve the target problem in reference to the base problem. The students couldn't solve the target problem, although they succeed to find the base problem. This comes from failing to discover the structural similarity between the target problem and the base problem. Especially it is important to cognize the proper corresponding of primary components between the base problem and target problem. And there is sometimes a part component of the target problem equivalent to the base problem and the target problem can't be solved without the insight into this fact. Consequently, finding the base problem fail to reach solving the target problem without the insight into their structural similarity. We have to make efforts to have an insight into the structural similarity between the target problem and the base problem to solve the target problem.

• 한국통신학회논문지
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• 제35권4A호
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• pp.341-349
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• 2010

본 논문은 차세대 이동통신 기술로 주목받고 있는 IEEE 802.16 기반의 Mobile WiMAX (또는 WiBro) 시스템에서 여러 가지 채널환경조건 및 기지국의 조건을 고려하여 기지국의 출력파워를 최적으로 설계하는 방법에 관한 것이다. 본 논문에서는 다양한 환경조건에서 Mobile WiMAX 시스템의 상/하향 링크버짓(link budget)을 산출하여, 이로부터 Mobile WiMAX 기지국의 최적 출력파워를 도출하는 방법에 대해 정리하였다. 본 논문에서는 MIMO(multiple input multiple output) 기술이 적용된 기존의 2Tx-2Rx 기지국과 여기에 수신단의 감도를 높이기 위해 수신단의 안테나 개수를 4개로 늘린 2Tx-4Rx 기지국과 성능을 향상시키기 위해 새롭게 빔포밍(beamforming) 기술이 적용된 4Tx-4Rx 기지국의 경우 등 총 세 가지 경우에 대하여 최적 출력파워를 도출하였다.