계층구조 무선망 셀룰라 시스템에서 신호세기 측정을 이용한 이동국의 위치와 속도 추정에 관한 연구

이상헌,김장섭,정우곤,최형진 成均館大學校 科學技術硏究所 1998 論文集 Vol.49 No.1

Estimating the positron and velocity of mobile stations is an important issue tar hierarchical cellular systems as the efficient allocation of mobiles to macro or microcells depends on its position and velocity. rower measurement method is applied and discrete location path-loss information is used to estimate the position of the mobile. Velocity estimation is treated in the same way with the position estimation problem since the mobility is the movement in a unit time. Lowpass smoothing technique and moving average are applied. The results prove to enhance the performance of the system. The path-loss data used in the simulator 2D-tracing method. Direction of _Future research in the topics are presented.

셀룰라 이동 통신 시스템에서 경로 손실 데이터베이스를 이용한 이동국의 위치와 속도 추정 방식

李相憲,鄭遇坤,崔炯辰 성균관대학교 1998 학술회의지원논문목록집 Vol.1998 No.-

차세대 셀룰라 이동통신 시스템은 기지국의 소형화와 서로 다른 크기의 기지국의 복합형태인 계층구조 셀룰라 형태를 가지게 되는데 이에 따른 시스템의 컨트롤은 이동국의 정확한 위치와 속도에 관한 추정을 전제로 한다[13]. 본 논문에서는 지금까지 연구되어온 이동국의 위치 추정 기법인 AOA(Angle of Arrival)와 TOA(Time of Arrival)및 TDOA(Time Difference of Arrival)의 방법을 설명하고 그 문제점을 분석하였고, 반사와 회절이 심하여 이동국의 위치 및 속도 추정이 어려운 마이크로셀 환경에서는 서비스 지역내 경로손실값의 이상 지역 데이터 베이스를 이용하여 이동국의 위치를 추정하는 방법을 제안하였다. 속도의 추정은 위치의 추정치로부터 시간에 대한 변화값으로 얻었다. 오차를 최소화하기 위하여 시스템의 Causality를 만족하는 범위 안에서 이동평균(Moving Average) 방법의 Smoothing을 적용하여 그 성능을 개선하였다. 또한 이산 지역 데이터 베이스의 탐색지역을 줄이는 방법을 제안함으로 시스템의 구현을 간단하게 할 수 있는 방안을 제시하였다. To achieve the required services in the next-generation cellular telephone systems, the size of the cell become smaller and/or is of mixed macrocells and microcells. To more efficient system control, we make use of the mobile position and velocity information, provided that the mobility information is relatively accurate. In this paper, we propose an improved version of path-loss measurement algorithm introduced in literature[11]. In microcellular structure with servere multipath fading, reflection and refraction make mobile position and velocity estimation very difficult. In the proposed method, the pre-recorded path-loss informations, called the discrete position data vase, are searched to estimate the position. Velocity estimation is obtained as a difference of the position values with respect to the time difference. Moving average is applied to smooth the estimated velocity and to reduce the error in the estimates. We also propose a method to simplify system implementation by reducing search area for discrete area datebaase.

Zn₄SnSe_(6):Co^(2+) 단결정의 물성에 관한 연구

이우선,오금곤,최창주,송찬일,김형곤 조선대학교 에너지.자원신기술연구소 2001 에너지·자원신기술연구소 논문지 Vol.23 No.2

In this paper, author describe the undoped and Co^(2+)-doped Zn₄SnSe_(6) single crystals were grown by the chemical transport reaction(CTR) method. For the crystal growth, the temperature gradient of the CTR furnace was kep a t 700℃ for the source aone and at 820℃ for the growth zone for 7-days. I t was found from the analysis of x-ray diffraction that undoped and Co^(2+)-doped Zn₄SnSe_(6) compounds have a monoclinic structure. The optical absorption spectra obtained near the fundamental absorption edge showed that these compounds have a direct energy gaps.

Y₂O₃함량에 따른 Al₂O₃- ZrO₂계 세라믹스의 특성

이형복,이홍림,홍기곤,김준태 연세대학교 산업기술연구소 1986 논문집 Vol.18 No.2

In this work the effect of Y₂O₃ content on Al₂O₃-ZrO₂ ceramics was studied and compared for coprecipitation and powder methods. Al₂O₃-ZrO₂ ceramics prepared by coprecipitation method showed the maximum M.O.R. value at 15 mole% ZrO₂ content for both 1.5 and 3 mole% Y₂O₃ addition, on the other hand, the ceramics prepared by powder method showed the increasing strength with increase of ZrO₂ content over the range of this work.

침전법에 의한 알루미나 분말제조 IV.ZrO₂의 분산에 의한 Al₂O₃/ZrO₂ 복합체의 제조 및 기계적 특성

홍기곤,이홍림,이형직,이호순 연세대학교 산업기술연구소 1992 논문집 Vol.24 No.2

In this study, a precipitation method, one of the most effective liquid phase reaction, was adopted in order to prepare high-tech Al₂O₃/ZrO₂ composite ceramics. Al₂(SO₄)₃·18H₂O, ZrOCl₂·8H₂O and YCl₃·6H₂O were used as starting materials and NH₄OH as a precipitation agent. Fine powders were prepared at optimum calcination condition. Sinterability of each fine powder and the effects of ZrO₂ on the grain size and mechanical properties of Al₂O₃ were investigated. The composition of Al₂O₃/ZrO₂ composites was fixed as Al₂O₃-15v/o ZrO₂(+3m/o Y₂O₃). The effect of MgO on the grain size of Al₂O₃ZrO₂ ceramics was also investigated.

침전법에 의한 알루미나 분말제조 Ⅲ. 소결체의 열적·기계적 특성

임헌진,이홍림,이형직,홍기곤 연세대학교 산업기술연구소 1992 논문집 Vol.24 No.1

A precipitation method was adopted in order to prepare high-tech Al₂O₃ceramics. Al₂(SO₄)₃·18H₂O was used as a starting materials and alumimum hydroxides were obtained by single precipitation method at the pH condition 7 and 11, using NH₄OH as a precipitation agent. Fine Al₂O₃powders were prepared at optimum calcination condition and were sintered at 1650℃ for 4 h in air. Microstructures and mechhanical properties of Al₂O₃ceramics were investigated. Doped MgO limited the grain growth of Al₂O₃and increased grain size homogeneity of Al₂O₃Flexural stregth values were 340∼430 MPa. Critical temperature difference?? was 175 K showing rapid strength degradation by thermal shock.

경통 및 요통 환자에서 세라젬 마스터 온열 치료기의 효과

신동배,이영수,전중선,김성원,강형곤 최신의학사 2000 最新醫學 Vol.43 No.9-10

악관절 수술후 안면신경 손상에 대한 임상적 연구

주재동,이의웅,김준배,박광호,김형곤 大韓顎顔面成形再建外科學會 1994 Maxillofacial Plastic Reconstructive Surgery Vol.16 No.4

Authors have studied retrospectively the facial nerve injury after TMJ surgery through the preauricular approach routine. The study material used was 4 patients of all 113 patients who were diagnosed as internal derangement and have been operated from March 1989 to February 1991 in Youngdong severance hospital, and were induced postoperatived facial nerve injury. The patient group who had the postoperative injured facial nerve was recognized degree of injury using the diagnostic method, Electromyography(EMG) and Nerve conduction test(NCT) which are used widely at present and was treated as conservative care and we identified the recovery time as the same method. The results as follows : 1. The meticulous care and precious surgical technique are needed in both operation and postoperation. During the TMJ surgery, the excessive retraction of the flap and frequent use of nerve stimulator and electric surgical knife should be avoided as possible and postoperative hematoma and swelling should be minimized. 2. The 4 patients were experienced with the postoperative facial nerve injury of all 133 patients who had been operated the TMJ surgery through the routine preauricular approach on our hospital. And the incidence of postoperative facial nerve injury happened was about 0.3% and its incidence was relatively low comparing with any other previous reports. 3. EMG and NCT were considered as useful methods which can diagnose the nerve injury objectively and identified the effect of treatment and recovery time. 4. The faical nerve-injured patients who were induced postoperatively after TMJ surgery, were diagnosed as second-degree nere injury through the EMG and NCT. And the patient group was treated well as conservative physical therapy for about 2 to 4 months.

계열화 및 전공코스제 운영방안

최병태,이형민,홍성준,정두진,김대곤 대구산업정보대학 2000 논문집 Vol.14 No.2

This paper is an attempt to propose our study that draw up a plan about faculty and major course to the Daegu Polytechnic College authorities. Our approach is a mixture of methods. It is systematic, in that it attempts to treat a college as a system. Through the second chapter, we examine the periodic, social, environmental, governmental, and economic context within which the College's developing effort must progress. Chapter three examines how the college systems actually design about faculty and major course. Thus, chapter four discusses how new faculty and major course participants attempt to compose a curriculum; chapter five accesses the institutions available in the College to distribute these designs. In conclusion, this paper presents that the College system would be better nine faculty; education and nurse·health field only be in administration unit, an information field be better divided into two parts: internet computer and information communication, and business and computer design faculty is established as intimate information. After all, the system will be characteristic in its information traits.

마이크로-매크로 셀룰라 시스템을 위한 계층선정 기법분석

김장섭,이상헌,정우곤,최형진 成均館大學校 科學技術硏究所 1998 論文集 Vol.49 No.1

A control scheme to select the appropriate layer between macro- and microcell hierarchical structure is considered. With the assumption that the each mobile speed is known to the system. the algorithm determines the optimal velocity threshold by which the cell section performed. The optimal criterion is to minimize the Grade of Service(GOS), a service criterion in cellular telephone systems. Mobile station with faster speed relative to the determined optimal speed threshold are assigned to a macrocell, while slower moving terminals are assigned to the smaller cells, i,e.. microcells. For the evaluation purpose for the proposed scheme, two different evaluation perspectives are compared and the algorithm proves to work