시공간 상관 MIMO 채널 시뮬레이터의 구현

정창규 忠州大學校 2008 한국교통대학교 논문집 Vol.43 No.-

This paper proposes a MIMO(Multi Input Multi Output) simulator with a SCM(Spatial Channel Model) that is suitable to a next mobile communication system with multiple antenna techniques. It is shown that SCM simulator have characteristics of temporal spatial correlation and delay spread. A proposed simulator is used as reference channel simulator in case of comparing with competitive techniques on mobile communication and analysing interference between other systems.

상향링크 채널추정을 위한 측정기준신호의 특징

정창규 한국교통대학교 2021 한국교통대학교 논문집 Vol.56 No.-

This paper propose the method of providing entire channel state to a base station using a restricted antenna of a mobile station. Generally, a MIMO system continue to sending a channel state to each other to update a current channel information. But, a restricted battery life don't make this condions being maintained. When mobile station send traffics to base station via a particular antenna of mobile station, a channel capacity is more efficient than a entire antenna of mobile station. the mobile station send weighting vecter of adjacent antenna via selected antenna. and each antenna of base station separate a proper time offset of received signal from base station. This change channel state immediately. It takes  ×  to transmit all weighting vecter of antenna of mobile station in TDM system. and one weighting value between a antenna of base station and that of mobile station is sended within   , where T is time for sending all wheighting vecter  ×  ,  is number of base station and  is number of mobile. Also power of mobile station is reduced to  .

직교 변.복조기의 채널불균형 보정특성

정창규,박한규 한국통신학회 1996 韓國通信學會論文誌 Vol.21 No.8

This paper presents a method of compensating for the gain and phase imbalance of quadrature modulator and demodulator. The gain and phase imbalance are compensated using the received power after the compensation pattern was transmitted at tranceiver. The proposed method is less vulnerable to changes in the transmission channel than the conventional method because compensation is made possible within the tranceiver system, and even the change in phase mblance in accordance with frequency can be compensated utilizing the adaptive algorithm. According to numerical results, a normalized eye opening and a bit error rate are improved by 1.8dB and 3.8dB, respectively.

결정적 접근을 사용한 이동국의 평균 전송률 예측

정창규 한국교통대학교 2018 한국교통대학교 논문집 Vol.53 No.-

This paper propose the estimation method of throughputs for each mobile stations in various channel circumstances. A stochastic approach based on a random process have complicated throughput equation so that there are a lot of difficult in application to real system. A deterministic approach have two assumptions. Each channel states decide the selection number and ratio of each mobile station. channel state of each mobile station is in steady state. When the mean and variance of a instantaneous throughput of each mobile stations are given, estimated mean throughputs are obtained for each variance values. Simulation results show that the estimation error of average throughput range from 9.2 % to 23.7 % and differ from real throughput by average 15.1%.

디지털 무선 시스템에 적용한 반복 알고리듬의 수렴성

鄭倉圭 충주대 2001 한국교통대학교 논문집 Vol.36 No.2

In this paper, the correction method of nonlinearity in digital radio system is proposed using a secant method as iterative algorithm.An adaptive processor with iterative algorithm updates the contents of Look up Table, and in baseband controls a RF device's characteristic variations owing to environment's change. A simulation shows that a transmitted signal after convergence of algorithm is similar to original signal without distortions.When the number of LUT (Look-Up-Table) address is increased the convergence time of predistortion value is increased but peak to side ratio is not changed.And also processing of more samples make error values of adopted algorithm converge to zero.

PF 스케쥴링 알고리듬을 채택한 TxAA 전송 다이버시티 시스템의 채널 용량 해석

鄭倉圭 충주대 2004 産業科學論文集 Vol.12 No.-

In this paper, the performane of TxAA transmit diversity(TD) system combined with proportinal fairness(PF) scheduling algorithm is analyzed under independent frequency flat Rayleigh fading. The PDF of instantaneous channel gain of the each user and average channel capacity are induced in case of single transmit antenna and TD system, respectively. Numerical results shows that TxAA TD technique with closed-loop array gain have a cooperative relationship with multiuser diversity.

용탕주조법을 이용한 금속복합재료 제조공정의 열전달 해석

정창규,정성욱,남현욱,한경섭,Jung, Chang-Kyu,Jung, Sung-Wook,Nam, Hyun-Wook,Han, Kyung-Seop 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.10

A finite element model is developed for the process of squeeze casting of metal matrix composites (MMCs) in cylindrical molds. The fluid flow and the heat transit. are fundamental phenomena in squeeze casting. To describe heat transfer in the solidification of molten aluminum, the energy equation is written in terms of temperature and enthalpy are applied in an axisymmetric model which is similar to the experimental system. A one dimensional flow model simulates the transient metal flow. A direct iteration technique was used to solve the resulting nonlinear algebraic equations, using a computer program to calculate the enthalpy, temperature and fluid velocity. The cooling curves and temperature distribution during infiltration and solidification were calculated fer pure aluminum. Experimentally, the temperature was measured and recorded using thermocouple wire. The measured time-temperature data were compared with the calculated cooling curves. The resulting agreement shows that the finite element model can accurately estimate the solidification time and predict the cooling process.

RF설계 파라미터를 이용한 CDMA2000 이동국의 최소규격분석

정창규 忠州大學校 2002 한국교통대학교 논문집 Vol.37 No.3

In this paper, a receiving system specifications of a CDMA2000 mobile station are analyzed based on the CDMA2000 3GPP2 MS Minimum Performance. Lately the minimum performance for the CDMA2000 mobile station was recommended. But the specification was given with the value of FER under certain conditions. This value is the reference to decide the design parameter. therefore system parameters for the CDMA2000 mobile station such as noise figure, selectivity, dynamic range, and intermodulation are derived and simulated based on the 3GPP2.

CDMA2000 이동국의 단일톤 간섭억제와 수신기 차단 특성 분석

정창규 忠州大學校 2003 한국교통대학교 논문집 Vol.38 No.3

This paper shows that noise figure and selectivity of RF part depend on system parameters such as single tone desensitization and receiver blocking. Noise figure of system is choosed by 8dB that is recommanded by Qualcomm. Simulation proved that In case of spreading rate of SR1 and code rate of 1/3, attenuation are -73.2dB and -62.2dB respectively when interference powers are -30dBm and -40dBm, and In receiver blocking characteristic, if noise figure of mobile station is 8dB, spreading rate is SR1, and jamming power is -102dBm, attenuations at point seperated by ±5000KHz from center frequency are -46dB and -46.8dB while code rate are 1/3 and 1/2, respectively.

지속가능발전교육 관점에 입각한 웹기반 기후변화 환경교육이 초등학생의 환경 인식 및 태도에 미치는 영향

정창규,이상원 이화여자대학교 사범대학 교과교육연구소 2010 교과교육학연구 Vol.14 No.3

본 연구는 웹기반을 활용한 기후변화 환경교육이 초등학생의 환경 인식과 태도에 어떠한 영향을 미치는지 알아보고자 하였다. 이를 위해 선행연구 고찰을 통하여 웹기반을 활용한 기후변화교육에 관한 교수·학습 모형 및 프로그램을 개발하고, 학습 현장에 적용하였다. 그 효과를 검증하기 위한 검사지는 황수정(2009)이 개발한 설문지를 재구성하였으며, 연구과정에서 얻어진 정량적 자료는 SPSS 12.0 프로그램을 이용하여 분석하고, 정량적 분석의 한계를 보완하기 위하여 정성적 분석을 실시하였다. 본 연구의 결과는 첫째, 지속가능발전 관점에서 바라본 기후변화에 관련된 내용을 추출 및 재구성하여 웹기반을 활용한 기후변화 환경교육을 위한 교수·학습 모형을 개발하고, 이를 바탕으로 환경교육 프로그램을 구안 및 적용시켰다. 둘째, 웹기반을 활용한 기후변화 환경교육 프로그램이 초등학생의 환경 인식 및 태도에 긍정적 영향을 미쳤다. 셋째, 웹기반을 활용한 기후변화 환경교육 프로그램의 적용은 지식적 측면에서는 차이를 보이진 않았다. 넷째, 웹기반을 활용한 기후변화 환경교육 프로그램을 적용한 후에 환경 인식이 높은 학생일수록 환경태도가 높게 나타났다. 결론적으로 웹기반을 활용한 기후변화 환경교육 프로그램은 초등학교 학교현장에 적용 가능하며, 다양한 환경교육 방법이 요구되고 있는 시점에서 새로운 교육방법으로써 그 가치가 크다고 할 수 있다. 차후 이와 관련된 심층적인 연구와 교수ㆍ학습 활동에 관한 후속 연구가 필요하다고 본다. The purpose of this study was to investigate the influence of the web-based climate change educational program on environmental awareness and attitudes of 5th grade elementary school students in Gyeonggi-Do. The students were divided into an experiment group and a control group. A reconstructed questionnaire through Hwang(2009)`s test tool was used to survey the affects of web-based climate change educational programs. The SPSS 12.0 program was used to analyze the results. The major results of this study were as follows: First, the researcher was able to develop and apply a professor-learning model for web-based climate change environmental education by extracting and recreating the climate change-related contents from 5th and 6th grader curriculum. Second, the web-based climate change educational program had a positive effect on elementary school students’ environmental awareness and attitude. Third, after implementing the web-based climate change educational program, the students with higher environmental awareness showed a higher regard for the environment. In conclusion, the web-based climate change educational program was effectively used on elementary school students and the program proved to have a positive affect on 5th graders’ environmental awareness and attitude. Therefore, in-depth study and follow-up research on teaching and learning activities should be highly considered.