전력선 채널에서의 DS/SSMA BPSK 코릴레이션 수신기 성능에 관한 연구

강병권,조창길,조관,이재경,황금찬,Kang, Byeong-Kwon,Cho, Chang-Gil,Cho, Kwan,Lee, Jae-Kyeong,Whang, Keum-Chan 한국통신학회 1992 韓國通信學會論文誌 Vol.17 No.9

본 논문에서는 전력선 채널에서 DS/SSMA BPSK 통신 시스템의 전형 및 하드리미팅 상관 수신기의 성능을 분석하였다. Chan의 잡음 모델을 이용하여 전력전에서 발생하는 강한 임펄스성 잡음을 배경 잡음에 대한 임펄스성 잡음의 전력 스펙트럼 밀도비 $(N_1/N_b)$, 데이터 폭에 대한 임펄스성 잡음 폭의 비(f). 임펄스성 잡음의 발생주기에 대한 임펄스 잡음 폭 (DF)등의 파라미터로 모델링하여, 각 파라미터 변화에 따른 시스템의 성능을 분석하고, 다중접속 간섭 잡음을 가우시안 근사화하여 각 수신기의 다중접속 능력을 평가하였다. 분석 결과 $N_1/N_b$가 작고 f가 1에 가까운 경우 전형 상관 수신기의 성능이 더 우수했으나, $N_1/N_b$가 증가함에 따라 하드리미팅 상관 수신기가 비트 오율 및 다중 접속 능력면에서 전형 상관 수신기보다 더 우수한 성능을 나타냈다. In this paper, the performance of linear and hard-limiting correlation receivers for DS/SSMA BPSK power line communication system is analyzed. Strong impulsive noise of power line is modeled with Chan's noise model, and the performance of both receivers is analyzed in terms of parameters such as ratio of power spectrum density of impulsive noise to that background noise, ratio in impulsive noise width th that of data bit, and interarrival time of impulsive noise. And also multiple access capacity is evaluated with Gaussian approximation of multiple access interference. The results of this analysis reveal that the performance of linear correlation receiver is superior to that of hard-limiting correlation receiver when $N_1/N_b$ is small and is close to 1. But the BER and the multiple access capacity of hard-limiting correlation receiver becomes better in comparison with linear correlation receiver as $N_1/N_b$ increases.

Back-Propagation Algorithm 상에서의 성능에 미치는 Parameters 분석에 관한 연구

강수연,박찬호,이현수 慶熙大學校 1994 論文集 Vol.23 No.-

신경망에서 가장 많이 사용되고 있는 알고리즘 중의 하나가 역전파(Back-Propagation) 알고리즘이다. 역전파 알고리즘에서 문제해결에 본질적인 영향을 주는 몇가지 요인들이 존재한다. 본 연구에서는 이 몇가지 요인들이 각각의 응용 문제의 해를 얻는데 미치는 영향을 시뮬레이션 결과를 통해 알아보고 이를 분석및 고찰 하였다. 고려 대상의 요인들로써는 learning rate, momentum, weight 초기값, 은닉 유니트수를 들 수 있다. 응용 문제 대상은 XOR 문제와 8*8 dot alphanumeric font 학습으로 하였다. Back-Propagation is one of algorithms that are currently used in neural network. It has some factors that basically affect on solving problems. On this paper, we analyze and investigate several learning parameters that effect on solutions of each application problems through simulation result. Considered factors are learning rate, momentum, initial weight values and the number of hidden units. Applied problems are XOR learning and 8*8 dot alphanumeric font learning.

敎養課程으로서의 「人口와 未來」開設 및 運營에 관한 實驗硏究 : 梨花女子大學校를 中心으로

康宇哲,徐洸善,田贊和,金在恩,蘇興烈 이화여자대학교 한국문화연구원 1979 韓國文化硏究院 論叢 Vol.33 No.-

This is a research report of the research that led to the opening of a population education course at Ewha Womans University. The research itself may be divided into the following four parts: planning for the research ; preparatory work for a population education course; opening of a population course; and evaluation of the population course. In the first stage of the research, the work, as usual, consisted of organizing the research team, setting up the research objectives, planning the research schedule, etc. The project began in the Fall of 1974, and concluded in the Fall of 1978. In the second stage of the research, the work was carried out for the preparation of a course in population education. Several sessions of faculty conference, in which more than 40 professors from various fields of specialization participated, were held in order to determine the specific objectives of the proposed course, to draw up a syllabus, and to prepare for a textbook for the course. When a rough sketch of the syllabus, and the contents of the course was made a student group was organized to examine and evaluate it. In the third stage of the research, a population education course titled "Population and Future" was opened as an elective course in the general education curriculum. This was in the Fall of 1875, and the course remained open every semester until now. An anthology with the same title as the course itself was used for reading, and the teaching was carried out as a team teaching by a team of 6-9 professors. In the fourth stage of the research, an evaluative study was taken up in order to evaluate the course with regard to its structure, textbook, teaching method, and its contents, as well as to assess the effectiveness of the course on terms of the students' change in their cognitive and emotive or attitudinal response to population problem.

CR-39 플라스틱飛跡檢出器에 의한 ^7Li(p, ^4He)^4He 核反應의 斷面積 測定

姜榮浩,安燦基,金道聖 慶北大學校 1984 論文集 Vol.37 No.-

The ^7Li(p,^4He)^4He reaction is used for in searches of universal abundance of Li, nuclear energy stages of ^8Be, and final step of p-p fusion cycle. In this work, we have detected and identified ^3He and ^4He from the ^6Li(p,^3He)^4He reaction and ^4He from the ^7Li(p,^4He)^4He reaction by the energy dependence of the etch pit diameter of the chemically etched tracks in CR-39. The target was 12㎍/㎠ thin film of natural lithium evaporated in the 10㎛/㎠ carbon backing. The target thickness was measured by Rutherford scattering of proton particles. For proton energies between 148keV and 462keV, differential cross section, angular distribution, and total cross section were measured. The results were compared with the previous measurements and Gamow-Diagram.

Pd 촉매 하에서 알릴 디올의 아릴화 연구 : 방향족 히드록시 케톤 및 페닐 치환된 알릴디올의 합성 Highly Selective Synthesis of Phenyl-Substituted Allylic Diols

강석구,정경윤,박찬희,남궁은영,김태현 성균관대학교 기초과학연구소 1995 論文集 Vol.46 No.2

The coupling reaction of iodobenzene with allylic diols in the presence of Pd(OAc)_2 and nBu_3P as catalysts using K_2CO_3 as base afforded the phenyl-substituted allylic diols. However, under the same reaction conditions with Et3N as base, phenyl-substituted α-hydroxy ketone was obtained.

TDI계 수분산성 폴리우레탄 접착제의 특성에 Diisocyanate의 구조가 미치는 영향

강승구,송봉근,이재흥,박찬조,류해일 한국공업화학회 2003 공업화학 Vol.14 No.3

수년 전부터 많은 연구자들에 의해 폴리우레탄의 수용화, 수분산화의 연구가 수행되어 왔다. 그럼에도 불구하고 폴리우레탄의 특성에 디이소시아네이트가 구조에 미치는 영향에 대한 연구는 많이 진행되지 않았고 또한 미흡한 상태이다. 따라서 번 연구에서는 디이소시아네이트의 형태와 함량 변화에 따른 폴리우레탄의 특성을 연구하였다. 폴리우레1탄 수분산체(PUD)는 poly(tetramethylent ether) glycol (PTMG), isophorone diisocyanate (IPDI), toluene 2,4-diisocyanate (TDI), dimethylol propionic acid (DMPA), trethylamine (TEA) 등을 사용하여 제조하였다. 제조한 폴리우레탄 수분산체(PUD)의 구조를 FT-IR을 이용하여 확인하였다. 폴리우레탄 수분산체의 특성은 DSC, gel permeation chromatography (GPC), particle analyzer, universal testing machine (UTM) 등을 사용하여 측정하였다. 폴리우레탄 수분산체(PHD)에서 입자크기는 IPDI 함량이 증가할수록 작아지는 경향을 나타내었으며, 유리전이온도(Tg)는 IPDI 함량이 증가할수록 조금씩 낮아지는 경향을 나타내었다. 또한, 폴리우레탄 수분산체(PUD)의 접착세기 변화에서는 [NCO]/[OH] 몰비를 1.2로 유지되도록 하면서 합성에 관여하는 [NCO] 양에 해당하는 [TDI]/[IPDI] 몰비를 변화시켜 얻은 폴리우레탄 수분산체의 접착세기는 [TDI][IPDI] 몰비가 50/50일때 좋은 집착세기를 나타내었다. 또한 [NCO]/[OH] 몰비를 1.6으로 일정하게 유지되도록 하고 [TDI]/[IPDI] 몰비를 변화시켜 얻은 폴리우레탄 수분산체의 접착세기는 [TDI]/[IPDI] 몰비가 75/25일 때 좋은 접착세기를 나타내었다. Aqueous polyurethane dispersions (PUD) has been investigated by many researchers for a long time. However, relatively little systematic work has been reported, in detail, on the effect of structure of the diisocyanate on the properties of polyurethane. This work describes the properties of polyurethane in relation to the variation of diisocyanate type and contents. Aqueous polyurethane dispersions (PUD) were prepared from the poly(tetramethylene ether) glycol (PTMG), toluene 2,4-diisocyanate (TDI), isophorone diisocyanate (IPDI), dimethyol propionic acid (DMPA), and triethylamine (TEA). Differential scanning calorimetry (DSC), FT-IR, GPC, universal testing machine (UTM), and particle analyzer were utilized to characterize the physical and mechanical properties of PUD according to diisocyanate type and contents. As the content of IPDI in PUD increased, the particle size decreased. The glass transition temperatures (Tg) of PUT were shifted to a lower temperature as IPDI conent increased. When [NCO]/[OH] mole ratio was 1.2, the adhesion force of PUD shown the best result at [TDI]/[IPDI] mole ratio of 50/50. And, at [NCO]/[OH] mole ratio of 1.2, the adhesion force of PUD was the best when [TDIl/[IPDI] mole ratio was 75/25.

空氣拳銃 擊發時 心拍數 變化에 관한 硏究

康燦金 단국대학교 1986 論文集 Vol.20 No.-

The result of investigation into the variation of the number of heart beating. The score rate by points and the point of impact by the position at firing an air rifle for the male shooter of B high school in Seoul has come out as the following. 1. The comparison of the score rate by points. In the a group. There were three who scored more than 20% from the total points 600.In the B group, on the other hand, there was only one. The rate of high gore in an average was in the A group that has many long experienced shooter, and of low score was in the B group. 2. The comparison of the point of inpact by the position. The shooters from A group K.K. N.,L.S.S., made 20%, 25.4% in the direction of 6~7o'clock, P.K.H.l8.3% in 4~5 0'clcrk, L.J.Y.21.7% in 7~8. From the B group, on the other hand, in the same direction of 7~8, K.M.H., H.S.W., K.S.K. made the same direction with 18.6,18.3,23.3%.The reason of uneven formation of the point of impact is the work of the individualities of the shooters. 3. The variation of the number of heart-beating at firing by the score, P.K.M. from the A group had faster heart beating while he was gaining in high score, others' heart beating, on the other hand were irregular. The reason can be interpreted as the shooters were selected without consideration for the synthetic aptitude.

압축력을 받는 결함이 있는 구조물의 주파수 해석

姜贊泳,柳擇仁,朴鳳賢,李晟熙,韓秉基 弘益大學校 科學技術硏究所 1998 科學技術硏究論文集 Vol.9 No.1

Vibration analysis of through-the-width-split beams for predicting buckling load is investigated based on Euler-Bernoulli beam theory. In split region, each segment is considered as a solid beam. In this region, recurrence equations relating integration constants for adjacent interior regions are established by satisfying continuity conditions at junctions of interior regions. The results of present study are compared with those of experiment and their results give good agreement with each other. From the result, it was shown that local buckling phenomena could appear in fundamental mode, however, there exists load carrying capacity after this phenomena.

유기구리시약을 이용한 광학활성 고리 카보네이트의 알릴화 연구

강석구,박찬희,정재욱 성균관대학교 기초과학연구소 1994 論文集 Vol.45 No.1

CuCN과 알킬리튬 시약을 이용하여 higher-order cuprate인 R_2Cu(CN)Li_2 또는 lower-order cuprate R_2Cu(CN)Li_2을 만들거나 Grignard시약과 구리촉매에 의해 R_2Cu(CN)MgX등을 형성시켜 이를 광학 활성 고리 카보네이트에 S_N2' 반응을 유도하여 높은 위치 선택성과 입체 선택성이 있는 광학 활성이 있는(E)-allylic alcohol 및 dienylic alcohol을 합성하였다. The S_N2'-type allylation reactions of chiral allylic cyclic carbonates with R_2Cu(CN)Li_2, R_2(CN)Li, or R_2Cu(CN)MgX afforded the alkylate(E)-allylic alcohol and dienylic alcohol with excellent high regio-and diasterecselectivity.

Pd(0)과 Ni(Ⅱ)촉매하의 Grignard시약에 의한 광학활성 고리카보네이트의 알릴화 연구

강석구,조동규,박찬희 성균관대학교 기초과학연구소 1993 論文集 Vol.44 No.2

NiCl_2(dppe)또는 Pd(PPh_3)_4를 촉매로 하여 Grgnard시약과 광학 활성 알릴고리 카보네이트를 반응시켜 높은 위치 선택성과 입체선택성이 있는 알킬화된 (E)-allylic alcohol을 얻었다. Reaction of chiral allylic cyclic carbonates with Grignard reagents in the presence of NiCl_2(dppe) or Pd(PPh_3)_4 as a catalyst afforded the alkylated (E)--allylic alcohols with high regio-and diastereoselectivity.