• 환경생물
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• 제27권2호
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• pp.176-182
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• 2009

전나무의 천연갱신 형태를 임분의 특성과 연관하여 내설악 길골 총 30지역에서 조사하였다. 임학적 의미의 천연갱신은 주로 예전에 인공적 교란이 있었던 곳에서 나타나며 자연림의 특성이 강할수록 오히려 의미를 상실한다. 이것은 인공적 교란이 천연갱신에 더 나은 환경조건을 제공하기 때문으로 보인다. 이와는 달리 자연림에서 갱신단계는 인공림처럼 명확할 수 없고 잠시 나타났다 사라지는 상태이며 세대교체는 임분구조 변화의 일부라는 표현이 적합하다. 특히 patch dynamic이 임분구조를 결정하고 주 구성수종이 음수인 전나무 자연림에서는 인공림에서 사용되는 천연갱신 개념은 원천적으로 의미를 상실할 것으로 보인다.

• 한국콘텐츠학회논문지
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• 제12권7호
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• pp.54-64
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• 2012

본 논문은 비주얼스토리텔링의 몰입을 위한 동일시 패턴에 관한 것으로 심리적 작용인 동일시를 시각적인 측면에서 연구하였다. 애니메이션에서 관객이 등장인물의 시선과 동일시가 이루어진 샷들만 분류하여 샷과 샷의 연결 구조를 기호학적 분석을 통해 코드화하였다. 규칙적으로 조직된 샷의 코드화 조합에서 특징적인 의미를 가진 동일시 패턴을 발견하였다. 이 패턴들은 특징적인 의미를 가지고 있기 때문에 내러티브 상황에 따라 선택하여 사용할 수 있다. 이에 실제 제작환경에서 활용가능한 동일시 시각 패턴을 제안하고자 한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.964-968
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• 2005

The standardization of information communication is doing a Internal each other connection and each other characteristic stability operation security in objective. From the low-speed network of the subway operation beginning currently it changes with the superhigh speed digital information transmission communication service environment which is a quality service, the hazard which plans the quality improvement of the efficient communication service use which hits to here and passenger service the standardization of the technical standard which stands and the improvement which hits to an engineering standard and facility must come to accomplish. The facility which existing is been old or the enclosure communication equipments which are insufficient. it improves, establishment itexpands efficiently, like this facilities it is stabilized and it is economic and rationally use maintenance it manages with the plan for the inside and outside of the country information communication relation technical standard and engineering standard service feature improvement and future expandability and economical efficiency, the possibility of having a pliability in order to be, rational technical standard and standard it takes a triangular position, efficient characteristic security of information communication service there is a place objective which promises the rational development of course city railroad communication system with character. Function improvement of enclosure communication base equipment, against an improvement and standardization plan it described trom the prosecution which it sees.

• 한국위성정보통신학회논문지
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• 제5권1호
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• pp.1-5
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• 2010

최근 전자 정보 통신 기술의 발전으로 개개인이 요구하는 정보의 전송량도 증가하고 있다. 특히 CATV의 전송량 증가에 따른 전송 성능의 향상이 불가피하다. 따라서 본 논문에서는 DOCSIS(Data-Over-Cable Service Interface Specifications) 2.0 요구 규격을 만족하는 CATV 전송 시스템에서 Bit Error Rate(BER)에 따른 최적의 Signal to Noise Ratio(SNR) 성능 요구 특성을 얻기 위한 위상 잡음 특성을 분석하였다. 특히 개발된 시뮬레이터를 이용하여 CATV 전송 시스템 위상 잡음 특성 요구 규격을 만족하는 Phase Locked Loop(PLL) 구성 요소 파라미터 값들을 도출하였다. 제시된 방법은 향후 초고속 CATV 전송 시스템의 위상잡음 관련 성능 요구 규격도출에 이용될 수 있다.

• 한국군사과학기술학회지
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• 제13권4호
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• pp.577-585
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• 2010

The Military Tactical Communication technology for effective network-centric warfare is developing. Targeting broadband wireless transmission, core technology for connection, and Transmission technology that secure survivability under High-speed Movement environment. On the one hand, Tactical data communication system that reflects military characteristic is developing on the base of Legacy communication equipment which is used in the field. Because almost every military units in the field have used voice to communicate which lower efficiency of operation, they have made effort to Substitute voice communication which delays military Operation Tempo to digital communication. The Communications environment of troops in Forward edge of battle field area is very poor. Especially in terms of limited frequency allocation and bandwidth. Therefore, improving the efficiency of frequency is essential for Military Tactical Communication. This paper is about The Data Compression Method for increase of Efficiency in Tactical Data Communication over Legacy Radios which are UHF, VHF, HF Radio. I proposed and proved the most efficient Data Compression Method that reflects military characteristic, after analyzing the experimentation, which simulate CAS(Close Air Support mission) data transmission between Pilot and TACP.

• Smart Structures and Systems
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• 제23권6호
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• pp.669-682
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• 2019

Vibration mitigation of cables or hangers is one of the crucial problems for cable supported bridges. Previous research focused on the behaviors of cable with dampers or crossties, which could help engineering community apply these mitigation devices more efficiently. However, less studies are available for hybrid applied cross-ties and dampers, especially lack of both analytical and experimental verifications. This paper studied damping and frequency of two parallel identical cables with a connection cross-tie and an attached damper. The characteristic equation of system was derived based on transfer matrix method. The complex characteristic equation was numerically solved to find the solutions. Effects of non-dimensional spring stiffness and location on the maximum cable damping, the corresponding optimum damper constant and the corresponding frequency of lower vibration mode were further addressed. System with twin small-scale cables with a cross-link and a viscous damper were tested. The damping and frequency from the test were very close to the analytical ones. The two branches of solutions: in-phase modes and the out-of-phase modes, were identified; and the two branches of solutions were different for damping and frequency behaviors.

• Steel and Composite Structures
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• 제30권2호
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• pp.185-199
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• 2019

Modular construction is an emerging technology to accommodate the increasing restrictions in terms of construction period, energy efficiency and environmental impacts, since each structural module is prefabricated offsite beforehand and assembled onsite using industrialized techniques. However, some innate structural drawbacks of this innovative method are also distinct, such as connection tying inaccessibility, column instability and system robustness. This study aims to explore the theoretical and numerical stability analysis of a tenon-connected square hollow section (SHS) steel column to address the tying and stability issue in modular construction. Due to the excellent performance of composite structures in fire resistance and buckling prevention, concrete-filled steel tube (CFST) columns are also taken into account in the analysis to evaluate the feasibility of adopting composite sections in modular buildings. Characteristic equations with three variables, i.e., the length ratio, the bending stiffness ratio and the rotational stiffness ratio, are generated from the fourth-order governing differential equations. The rotational stiffness ratio is recognized as the most significant factor, with interval analysis conducted for its mechanical significance and domain. Numerical analysis using ABAQUS is conducted for validation of characteristic equations. Recommendations and instructions in predicting the buckling performance of both SHS and CFST columns are then proposed.

• 한국지역사회생활과학회지
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• 제20권2호
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• pp.263-274
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• 2009

The objective of this study is to verify work satisfaction of school food-service employee, of their job characteristics. Subjects were comprised 9 elementary schools, 11 middle schools, and 3 high schools in Ansan city. Data were analyzed 203 questionnaires for frequency, means, one-way ANOVA, $Scheff{\acute{e}}$ test, t-test, and Pearson correlation using SPSS PC Package. Most of the respondents were high school graduate(91.1%), under one million won salary(41.9%), and non license holder(60.6%). Working conditions were part-time job(41.9%), unlimited contractors(51.2%), and 3-5 years of working experience(21.7%). Measure of overall job satisfaction by Likert-type 5 scale, satisfaction of work operation attitude was 3.55 points and work characteristic duty of 4.32 points. The certificate qualified and elementary school's working posture were more satisfied their work attitude than other groups(p<0.05). Salary satisfaction score showed 2.64 points, but the work esteem satisfaction showed 3.34 points. The factor of working circumstance and potentiality satisfaction was only 2.61 points, but interpersonal connection and communication satisfaction was 3.50 points. Between job satisfactions factors, they were highly correlated with each other. The pride and characteristic duty of the work showed the strongest correlated(p<0.001). The satisfaction score of work operation attitude were significantly correlated with characteristic duty(p<0.001), work esteem, interpersonal relationships and communication(p<0.01). With this results, work satisfaction of food service employees showed a relatively high to perform a job task characteristics and work attitudes. However, the working environment and growth in salaries satisfaction were low. A set of duties must be paid according to the labor intensity. As removing the disturbing factors, the improvement in the quality of the feed will be able to expect substantial effects.

• 센서학회지
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• 제11권1호
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• pp.1-8
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• 2002

온도 측정이 필요한 다양한 용도의 소자에 응용되고 있는 열전쌍열(thermopile) 제작에 SOI 구조를 응용하여, 특성을 개선하였다. 열전쌍열을 구성하는 저항체가 단결정 실리콘으로, 제벡 계수(seebeck coefficient)가 높은 재료일 뿐 아니라, 실리콘 저항체를 산화막을 이용하여 실리콘 기판과 절연 분리한 구조로 되어있어서, 기존의 이온주입 공정에 의해 불순물을 주입하는 방법으로 제작된 저항체에 비해서 두 접점(hot junction 및 cold junction) 사이의 열 전달을 극적으로 감소시킬 수 있어서 소자의 특성을 개선할 수 있었다. 열전쌍열은 p형 단결정 실리콘 저항체 17개 및 n형 17개를 직렬 연결로 구성했다. 저항체의 길이 $1600{\mu}m$, 폭 $40{\mu}m$, 두께 $1{\mu}m$으로 제작된 열전쌍열에 빛을 조사하여 소자 양단에 온도차를 발생시키고, 그 때 발생하는 기전력을 측정한 결과 130mV/K의 우수한 특성을 나타냈다.

• 전기전자학회논문지
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• 제2권1호
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• pp.122-133
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• 1998

ITU-T(International Telecommunication Union-Telecommunication)에 의하여 정의된 CBDS(Connectionless Broadband Data Service)을 위한 CL 망은 프레임을 라우팅해 주는 CL(ConnectionLess) 서버와 CL 가입자와 CL 서버 또는 CL 서버를 연결해주는 링크들로 구성된다[1][2]. 이와 구성에서 두 종류의 폭주, 즉, CL 링크 폭주와 CL 서버 폭주가 일어날 수 있다. 따라서 본 논문에서는 ATM 망을 통하여 LAN 간 연동 시 위에서 언급한 LAN 트래픽의 폭주 상황에 효율적으로 대처할 수 있는 방안을 제안하였다. 제안한 방안은 링크 바이 링크 방안과 하이브리드 방안이다 링크 바이 링크 방안은 CL 가입자와 CL 서버간, CL 서버간 링크 단위 ABR 궤환 루프와 CL 서버의 라우팅 기능을 수행하는 헤더 변환 테이블을 이용한 것이다. 그리고 하이브리드 방안은 링크-바이-링크 방안에 CL 계층의 종단간 루프를 첨가하고 CL 계층에서 CLNAP-PDU (ConnectionLess Network Access Protocol - Protocol Data Units)를 이용한 RM 메시지를 이용하는 방안이다. 이 방안 모두는 ATM 계층의 ABR 루프와 CL 계층의 종단간 루프, 그리고 CL 서버의 라우팅 기능을 이용하기 때문에 쉽게 구현될 수 있다. 따라서 본 논문에서는 CL 서버에서 두 가지 방안에 대한 특성과 장단점이 비교 분석되었다.