• Journal of Advanced Marine Engineering and Technology
• /
• 제38권9호
• /
• pp.1137-1140
• /
• 2014

선박의 전동기에 고장이 발생하면 대개 육상에서 수리 후 본선에 다시 재설치 되고 있으나 연결 단자의 기호 표시가 지워지거나 분명치 않을 때는 결선과정에서 전동기 권선의 극성 구별이 어려워진다. 이로 인해 Y-${\delta}$ 기동의 전동기에서 한 권선의 극성을 반대로 잘못 연결하는 경우 전원 투입과 동시에 과다한 전류가 흐르면서 재차 2차 고장으로 이어질 위험이 있다. 이러한 문제와 관련하여 본 논문은 고정자의 1상 권선에 미소 직류전류를 흘릴 때 나머지 권선들에서 유도되는 과도 기전력의 특성을 토대로 아날로그 멀티테스터를 이용한 고정자 권선의 극성 판별법을 제시하고 관련 특성을 분석한다. 또한, 이 같은 방식을 실제 전동기에 적용하여 단계적인 측정과정을 통해 단자연결의 이상여부를 현장에서 용이하게 판별할 수 있는지를 확인해 보기로 한다.

• 조명전기설비학회논문지
• /
• 제20권5호
• /
• pp.57-63
• /
• 2006

본 논문은 낙뢰에 의해서 방사된 전계와 자계 파형의 물리적 특성과 파라미터분석에 대한 것으로 낙뢰에 의한 전계와 자계 파형은 각각 평판형 전계센서와 루프형 자계센서로 검출되고, 측정된 신호는 12 비트의 해상도, 10[MS/s] 샘플링, 10[ms]의 기록시간을 가지는 데이터취득시스템으로 기록하였다. 낙뢰에 의해 발생한 전계와 자계 파형의 극성의존성은 거의 없었으며, 상승시간은 $13[{\mu}s]$이내이고 정 부극성의 평균값은 각각 $4.1[{\mu}s],\;4.2[{\mu}s]$이었다. 정 부각성의 영점교차시간은 각각 $65.2[{\mu}s],\;67.0[{\mu}s]$이고, 반전딥의 깊이는 38.0[%], 40.3[%]이었다.

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 2008년도 Asian Magnetics Conference
• /
• pp.174.1-174.1
• /
• 2008

• Journal of Power Electronics
• /
• 제17권4호
• /
• pp.933-941
• /
• 2017

In this paper an improved low frequency selective harmonic elimination-PWM (SHE-PWM) technique for Cascaded H-bridge (CHB) converters is proposed. The proposed method is able to eliminate low order harmonics from the output voltage of the converter for a wide range of modulation indices. To solve SHE-PWM equations, especially for low modulation indices, a modified method is used which employs either the positive or negative voltage polarities of H-bridge cells to increase the freedom degrees of each cell. Freedom degrees of the switching angles are also used to increase the range of available solutions for non-linear SHE equations. The proposed SHE methods can successfully eliminate up to $25^{th}$ harmonic from a 7-level output voltage by using just nine switching transitions or a 150 Hz switching frequency. To confirm the validity of the proposed method, simulation and experimental results have been presented.

• 자원환경지질
• /
• 제19권2호
• /
• pp.153-163
• /
• 1986

Paleomagnetic and geological studies of volcanic and sedimentary rocks of Jeju Island have been carried out to determine the position of virtual geomagnetic pole(VGP), and to estimate the geological sequence and their age. As a result of paleomagnetic studies, the reversal polarities are measured in the Sanbangsan trachyte and Hwasun formation, and the normal are the rest. In case of normal polarity, the mean values of declination and inclination are $2.3^{\circ}$ and $48.4^{\circ}$, respectively, and the average value of VGP is $85.4^{\circ}N$ and $79.9^{\circ}W$. The locations of VGP's are coincident with those obtained from world-wide Plio-Pleistocene rocks. The Hwasun formation and Seongsan formation which have been known to be sedimented in the similar time in the 2nd-stage of volcanic eruption, possess reversal and normal polarities, respectively. This fact brings about the result that two formations should be separated in a sense of geological sequence. Consequently, the geological sequence of the 2nd-stage of volcanic eruption is Pyoseonri basalt-Seoguipo hawaiite-Hwasun formation-Seongsan formation-Jungmun hawaiite-Sanbangsan trachyte. Referring to the paleomagnetic studies and the previous and present geological studies, Seoguipo formation corresponds to the Gauss normal epoch, the 2nd-stage of volcanic eruption to Matuyama reversed epoch, and the 3rd-, 4th-, and 5th-stages to Brunhes normal epoch. Therefore, the Seoguipo formation is mostly sedimented during late Pliocene and/or presumably extended to the early Pleistocene. The rocks of the 2nd- to 5th-stage are formed later than this.

• 한국어정보학회:학술대회논문집
• /
• 한국어정보학회 2016년도 제28회 한글및한국어정보처리학술대회
• /
• pp.195-200
• /
• 2016

본 연구는 MUSE 감성 코퍼스를 활용하여 문장의 극성과 키워드의 극성이 얼마만큼 일치하고 일치하지 않은지를 분석함으로써 특히 문장의 극성과 키워드의 극성이 불일치하는 유형에 대한 연구의 필요성을 역설하고자 한다. 본 연구를 위하여 DICORA에서 구축한 MUSE 감성주석코퍼스 가운데 IT 리뷰글 도메인으로부터 긍정 1,257문장, 부정 1,935문장을, 맛집 리뷰글 도메인으로부터는 긍정 2,418문장, 부정 432문장을 추출하였다. UNITEX를 이용하여 LGG를 구축한 후 이를 위의 코퍼스에 적용하여 나타난 양상을 살펴본 결과, 긍 부정 문장에서 반대 극성의 키워드가 실현된 경우는 두 도메인에서 약 4~16%의 비율로 나타났으며, 단일 키워드가 아닌 구나 문장 차원으로 극성이 표현된 경우는 두 도메인에서 약 25~40%의 비교적 높은 비율로 나타났음을 확인하였다. 이를 통해 키워드의 극성에 의존하기 보다는 문장과 키워드의 극성이 일치하지 않는 경우들, 가령 문장 전체의 극성을 전환시키는 극성전환장치(PSD)가 실현된 유형이나 문장 내 극성 어휘가 존재하지 않지만 구 또는 문장 차원의 극성이 표현되는 유형들에 대한 유의미한 연구가 수행되어야 비로소 신뢰할만한 오피니언 자동 분류 시스템의 구현이 가능하다는 것을 알 수 있다.

• Journal of Electrical Engineering and Technology
• /
• 제11권1호
• /
• pp.184-191
• /
• 2016

In recent years, there are a number of studies that have been carried out to explore the alternative for Mineral Oil (MO) as dielectric insulating fluid in transformers due to the increasing tight regulation on safety and environment. Vegetable oils have been identified as suitable candidate since it is biodegradable, non-toxic and high flash/fire points which ensure more in-service safety. Among the types of vegetable oils considered for transformers application are Palm Oil (PO) and Coconut Oil (CO). This paper presents an experimental study on the lightning breakdown voltages of PO and CO under non-uniform electric field based on needle-sphere electrodes configuration at 3 small gap distances. The type of PO used in this study is Refined Bleached and Deodorized Palm Oil (RBDPO) Olein. The main focus of this study is to examine the lightning breakdown performance of RBDPO and CO under different test conditions and assess its suitability as dielectric insulating fluid in transformers. The effect of voltage polarities (positive and negative) and testing methods (rising-voltage, up-and-down and multiple-voltage) were investigated. The data obtained from all tests were analysed by Weibull distribution in order to determine the withstand voltages for each type of oils. It was found that the breakdown voltages of RBDPO and CO are comparable with MO under positive lightning impulse. Under negative lightning impulse, the breakdown voltage of MO is slightly higher than RBDPO and CO. There is no significant effect of testing methods and voltage polarities on lightning breakdown voltages of RBDPO and CO. Based on the statistical analysis, it is found that the breakdown voltages of RBDPO and CO at 1% probability are slightly lower than MO.

• Journal of Pharmaceutical Investigation
• /
• 제21권3호
• /
• pp.133-141
• /
• 1991

The fluorescence characteristics of l-anilinonaphthalene-8-sulfonate (ANS) and 2-p-toluidinylnaphthalene-6-sulfonate (TNS) made the dyes useful probes for the determination of the polarity at the binding sites of several water-soluble polyparacyclophanes. Polyparacyclophanes used were 1,6,20,25-tetraaza[ 6.1.6.1]paracyclophane (CPM 44), 1,7,21,27 -tetraaza[7.1.7.1]paracyclophane (CPM 55). 1,7,21,27 -tetraaza-14,34-dioxa[7.1.7.1]paracyclophane (CPE 55) and 1,8,22,29-tetraaza-15,36-dioxa[8.1.8.1] paracyclophane (CPE 66). The fluorescence quantum yield, emission maximum, and half bandwidth of ANS or TNS obtained in a variety of solvent systems were plotted as a function of four kinds of empirical solvent polarity scales such as dielectric constant (D), (D-l)/(2D+1). Y and Z values. It was found that the Z-value-emission maximum $(\overline}V_F,\;cm^{-1})$ profile showed the most reliable linearity. ANS and TNS interacted with CPM 44, CPM 55, CPE 55. CPE 66. ${\alpha}-cyclodextrin$ (CyD) and ${\beta}-CyD$ in the aqueous solution, and from the emission maxima the polarities (Z-value) of their binding sites were calculated to be 92.65, 87.50, 93.35, 84.52, 94.36, and 90.48 for ANS, respectively. and 91.07, 89.68, 85.44, 86.74 and 87.6 for TNS except for ${\alpha}-CyD$, respectively.

• 한국실내디자인학회논문집
• /
• 제17권1호
• /
• pp.19-29
• /
• 2008

The purpose of this study is to reveal that the concept of relation in the postwar CIAM's debate was the hot issue which leaded to the collapse of CIAM, and that Aldo van Eyck developed it into the concept of "in-between". The postwar CIAM's young members voiced a critique of the universalizing attitude toward dwelling that CIAM had pursued since 1928 and looked for a new approach that would take into account the relation around dwelling. So, this study reviews the concepts of relation which were proposed by the postwar CIAM's young members. As a result, it is revealed that Aldo van Eyck extended the concept of "in-between" not to have the polarities, such as inside/outside, close/open, part/whole, neutralize or cancel one another out, but to attune them in such a way that they reinforce each other by mutual contrast, while the other young CIAM's members limited it to transition or connection. And, this paper analyzes the Municipal Orphanage in Amsterdam which was presented in CIAM 10. Through the analysis, it is revealed that the building presents many polarities simultaneously such as those; indoor and out door realms, dynamics and immutability, part and whole, and so on. In conclusion, it is possible to recognize that the concept of "in-between" is the fundamental binary-compound relation that lies at the root of Aldo van Eyck's architectural thought and bears on an interaction on a reciprocal relation between the inhabitant and the built environment.

• 한국통신학회논문지
• /
• 제30권9C호
• /
• pp.860-870
• /
• 2005

본 논문에서는 karnaugh map(k-map)상의 셀을 이용하여 $2^{n}$개의 서로 다른 극수(polarity)를 갖는 GRM(Generalized Reed-Muller)상수를 생성하는 새로운 기법을 제안하였다. n개의 입력변수에 대한 일반적인 GRM 함수의 생성 방법은 단일 변수에 대한 변환 행렬을 구하고 이를 n번의 Kronecker 곱을 행한 변환 행렬을 이용하여 GRM 상수를 구하는 것이다. 이런 방법을 사용하는 경우, 변수의 숫자가 증가함에 따라 변환 행렬의 차수가 $2^{n}\times2^{n}$로 커지는 단점을 갖는다. 이에 반하여 본 논문에서는 k-map상에서 변수를 축약시킨 셀 [$f_{i}$]을 구하고 이를 단일 변수 변환 행렬과 연산하여 GBM 상수를 구하는 새로운 기법을 제안한다. 본 논문에서 제안한 새로운 방법과 타 논문과의 비교를 한 결과, 기존 방법은 가산기, 승산기, KP(Kronecker 곱 승산기)회로가 필요한데 반하여 본 논문에서는 가산기만이 필요하므로 효율적인 VLSI 설계에 유리하다