• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.709-710
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• 2008

In this paper, we calculated permanent magnetic linkage flux ${\psi}_{\alpha}$ and Ld, Lq parameters of IPMSM and compared two model which has different barrier width. IPMSM has two kinds of torque that reluctance torque and magnetic torque. In constant torque region, using the Maxwell stress tensor method, we calculated the torque and current phase angle ${\beta}$ which has appeared maximum torque. In weakening flux region, we calculated the current phase angle ${\beta}$ which flux ${\psi}_o$ lower than limited flux ${\psi}_{omax}$. From the current phase angle ${\beta}$, we calculated torque by torque equation and compared two model characteristic.

• The Journal of the Acoustical Society of Korea
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• 제20권1E호
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• pp.20-24
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• 2001

We propose the computation reduction method of real root method that is mainly used in the CELP(Code Excited Linear Prediction) vocoder. The real root method is that if polynomial equations have the real roots, we are able to find those and transform them into LSF[1]. However, this method takes much time to compute, because the root searching is processed sequentially in frequency region. But, the important characteristic of LSF is that most of coefficients are occurred in specific frequency region. So, the searching frequency region is ordered by each coefficient's distribution. And coefficients are searched in ordered frequency region. Transformation time can be reduced by this method than the sequential searching method in frequency region. When we compare this proposed method with the conventional real root method, the experimental result is that the searching time was reduced about 46% in average.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.32-33
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• 2009

We propose viewing angle switchable liquid crystal display(LCD) associated with fringe-field switching (FFS) mode with high aperture ratio characteristic. This device is composed of R(red), G(green), B(blue), pixel and W(white) pixel in which R,G,B pixel shows image and white pixel for both viewing angle control and image. Conventional viewing angle controllable liquid crystal display has not transmittance because the liquid crystal only tilts up without rotates in viewing angle control region. In this paper, we suggested that the device has high transmittance characteristic because the LC directors are rotated in which viewing angle control region are generated fringe electric field.

• 건축역사연구
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• 제19권5호
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• pp.7-23
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• 2010

The aim of this study is to analyze the planar composition of rectangular formation houses in 8 areas, both cities and counties, in the sphere of Andong and to reveal the characteristics of these houses in each region. This study of the rectangular formation of houses and their characteristics will facilitate an understanding of the general trends of housing in Andong cultural area.. In this study, the subject houses are composed of three parts: Bonchae, Anchae, and Sarangchae, and the author classified the planar types of the houses. The differences in the regional planar types were analyzed through visual and statistical methods. The analyzed results reveal the regional characteristics of the rectangular formation houses in terms of their planar aspects in the Andong region. The distribution showed the greatest preference toward one type out of two types of distribution of Bonchae, Anchae, and Sarangchae. The ratio for the higher distribution was approximately 70%, whereas the ratio for the lower distribution was around 20%. For convenience, the type with a higher distribution rate is referred to as the "major type," and the type with a lower distribution rate is termed the "minor type." The complete-type houses (73%) in Bonchae were a major type there, and the symmetric-type houses (73%) in Anchae were the major type in that location. In addition, the corner-type houses (72%) in Sarangchae were the major type. In the regional distribution of major types and minor types in the 8 regional cities and counties, regional differences were noted. The three regional groups can be divided into A, B, and C according to the distribution ratio. Andong, Bonghwa, and Yecheon belong to region A. that shows a variety of distribution types and a dispersive trend. Yeongyang and Yeongdeok belong to region C that shows a simplified trend.Yeongju and Cheongsong belong to region B.

• 대한산업공학회지
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• 제23권4호
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• pp.825-833
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• 1997

The purpose of this paper is to develop a method of postoptimality analysis that can be applied to an optimal solution of a maximum flow problem. We first use the transformed network corresponding to a given network. In such a network we conduct postoptimality analysis by determining changes in the optimal solution precipitated by changes in the capacity as the arc capacity varies from 0 to infinite. By this method we can easily calculate not only the characteristic region where the given optimal solution remains unchanged, but also the characteristic region where the value of the maximal flow gradually increases or decreases. The proposed method is demonstrated by numerical example.

• 한국CDE학회논문집
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• 제6권4호
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• pp.215-221
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• 2001

In the zigzag milling of a pocket having islands, tool retraction is one of the primary factors that decrease productivity. Therefore, tool path with minimum number of tool retraction has been needed. Most researches about this topic have been concentrated on obtaining the optimum solution formulated through the geometric reasoning off pocket. Recently, several attempts were made to simplify this problem into region partitioning in order to get the numerically expressed minimum solution. In this research, a method reducing the number of tool retractions extended from existing region partitioning is provided. Applying the segment that is normal to the reference direction of zigzag milling, region partitioning is carried out and structural elements of the region are searched via graphs of islands and characteristic points. Through the processes presented, the number of region partitioned is less than that of existing processes.

• Bulletin of the Korean Chemical Society
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• 제6권2호
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• pp.103-107
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• 1985

Quantum chemical calculations were carried out to explain how the electronic states of some series compounds vary with metabolic activation. Compounds studied included aromatic amines and amides, polycyclic hydrocarbons, and a few alkylating agents that do not require metabolic activation. The 1, 2 and 4 positions forming the trans-butadiene frame of a molecule, henceforth referred to as "the trans 1, 2, 4 region", have seen to be important positions for the prediction of carcinogenic activity of these compounds. It is also evident that their electrophilic properties increase with metabolic activation. That is the sum of ${\pi}$-electron densities of the trans 1, 2, 4 region in the lowest unoccupied molecular orbital (LUMO) has been found to increase in the order of precarcinogens < proximate-ones < the carbocation ultimate-ones. This is consistent with the fact that chemical carcinogens become more strongly electrophilic with activating. This region not only provides a unified view of structurally diverse carcinogens, but also predicts uniformity in their reactive sites. Accordingly, we suggest that an understanding of the trans 1, 2, 4 region would be helpful in elucidating the mechanism of carcinogenesis.

• Journal of Electrical Engineering and Technology
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• 제9권2호
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• pp.686-694
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• 2014

A power semiconductor device, usually used as a switch or rectifier, is very significant in the modern power industry. The power semiconductor, in terms of its physical properties, requires a high breakdown voltage to turn off, a low on-state resistance to reduce static loss, and a fast switching speed to reduce dynamic loss. Among those parameters, the breakdown voltage and on-state resistance rely on the doping concentration of the drift region in the power semiconductor, this effect can be more important for a higher voltage device. Although the low doping concentration in the drift region increases the breakdown voltage, the on-state resistance that is increased along with it makes the static loss characteristic deteriorate. On the other hand, although the high doping concentration in the drift region reduces on-state resistance, the breakdown voltage is decreased, which limits the scope of its applications. This addresses the fact that breakdown voltage and on-state resistance are in a trade-off relationship with a parameter of the doping concentration in the drift region. Such a trade-off relationship is a hindrance to the development of power semiconductor devices that have idealistic characteristics. In this study, a novel structure is proposed for the Insulated Gate Bipolar Transistor (IGBT) device that uses conductivity modulation, which makes it possible to increase the breakdown voltage without changing the on-state resistance through use of a P-floating layer. More specifically in the proposed IGBT structure, a P-floating layer was inserted into the drift region, which results in an alleviation of the trade-off relationship between the on-state resistance and the breakdown voltage. The increase of breakdown voltage in the proposed IGBT structure has been analyzed both theoretically and through simulations, and it is verified through measurement of actual samples.

• KIEAE Journal
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• 제12권1호
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• pp.11-19
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• 2012

The subject of this study is capital area including Seoul and Incheon, and metropolitan area including Daejeon and Busan among urban redevelopment project district that are currently promoting urban redevelopment project. Data for analysis is implemented collected through visiting each households in project district. Resettlement decision characteristics are analyzed with considering householder's characteristic, house member's characteristic, residential space's characteristic, and area characteristic of families residing in urban redevelopment project area. Through researching characteristics and preferences of residents in project area by urban redevelopment business, improvement were found and implications were provided. Consequently, there are many factors to consider resettlement when deciding household's resettlement when deciding on household's resettlement after the redevelopment project depending on household's characteristics. So, political methods are needed to accomplish urban redevelopment project by resident's position through characteristic and preference survey of resident on project district. Therefore, the study can be utilized as basic data that considers characteristic of each households and region when establishing house policy in order to correspond to housing market that satisfies future consumer's demand.

• 전자공학회논문지S
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• 제36S권1호
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• pp.70-80
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• 1999

본 논문에서는 인간 시각 체계에 기반하여 주관적 화질의 열화없이 전송 정보량을 효과적으로 줄일 수 있고, 또한 전송 정보량을 조절할 수 있는 영역기반 초적속 부호화에 적합한 새로운 계층적 영상 분할 알고리즘을 제한한다. 제안한 알고리즘은 각 단계에서 수리 형태학에 기반한 영상 분할과 인간 시각 체계를 고려한 영역 볍합 고조로 이루어져 있다. 영상분할은 3단계의 계층적 구조로 이루어져 있으며, 영역 병합은 각 단계에서 인간 시각 체계에 기반하여 인간 시각이 구분할 수 없는 두 인접 영역의 쌍들을 추출한 후 영역 병합을 수행한다. 이때 인간 시각 체계에 기반하여 병합할 영역을 추출하고 제안한 병합을 우선 순위 함수에 의한 병합 우선 순위에 따른 영역 볍합ㅇ르 차례로 수행하여 영역의 수를 효과적으로 줄임으로써 영역기반 초저속 부호화시 과다한 윤곽선 정보로 인한 병목현상을 개선할 수 있다. 그리고 각 단계에서의 영역 병합시 정보량 조절 요소 값에 따라 전송 정보량을 조절할 수 있어 기존의 방법보다 유연한 분할 구조를 나타낸다. 실험을 통하여 제안한 방법은 기존의 방법보다 PSNR 및 주관적 화질은 유사하나, 전송할 윤곽선 정보는 상당히 줄일 수 있어 영역기반 초적속 부호화를 위한 효율적 영상 분할 알고리즘임을 알 수 있다.