교환기용 객체지향 데이타베이스 시스템 개발 ( The Development of Object-Oriented Database System in Switching System )

정희택,이길행,조주현,김용민,노봉남 한국통신학회 1995 한국통신학회 학술대회논문집 Vol.14 No.2

한국 거시경제정책의 효율성에 관한 고찰

정희택 한국경상학회, 한국국민경제학회 2003 경제연구 Vol.21 No.4

계량모형이 정책결정에 이용될 수 있는가라는 질문에 대하여 Kydland-Prescott은 계량모형을 이용하여 설정한 정책이 최적이 아님을 보였다. 그러나 Sims는 계량모형이 충분히 신축적이라면 계량모형이 정책결정에 이용될 수 있다고 주장하였다. 이 논문에서는 정책결정자들이 실제경제에 관해서 정확한 인식을 하지 못하고 있더라도 신축적인 모형을 이용한다면 효율적인 정책을 설정할 수 있음을 보였다. 계량모형은 베이지안모형을 기초로 하여 파라메터에 시간변환을 가정하였고 그 추정치들은 매번 칼만필터를 이용하여 갱신되었다. 정책의 효율성은 시뮬레이션을 이용하여 고인플레이션 균형과 저인플레이션 균형 중 어느 것에 가까이 도달하는 가에 따라서 판정하였다. 우리는 84년에서부터 환율위기 이전까지의 자료를 이용하여 한국거시정책의 효율성을 평가하였다. 이 기간에 있어서 한국의 거시정책은 고인플레이션 균형에 머물러 있었다. Regarding to the usefulness of econometric model for the policy analysis, Lucas says that the econometric model can not be used for policy analysis. And Kydland and Prescott show that the time consistent equilibrium reached using the econometric model is not optimal. But Sims says that the econometric model can be used for policy analysis if the model is flexible enough. We extend Kydland-Prescott model such that the parameters are time varying and Bayesian. In this model policy makers do not understand the true model but they are using flexible econometric model and update the parameter values each period using Kalman filter. We show the behavior of the model by simulation. Based on the parameter value, the model can reach high inflation equilibrium which is not optimal or low inflation equilibrium which is optimal or near optimal. We evaluate the optimality of the economic policy in Korea. We apply this model to the Korean data from 1984~1996. The model shows that the inflation stays high for the next 400 periods. That means the macroeconomic policy is not optimal for this period. As we set up the model. there is a parameter that reflects the relative importance of inflation and unemployment. The estimated value can be interpreted that the policy makers put more importance on unemployment than on inflation.

철골모멘트골조 약축접합부 내진성능 평가

정희택,윤석용,오경환,이강민 대한건축학회지회연합회 2007 대한건축학회지회연합회 학술발표대회논문집 Vol.2007 No.1

This paper summarizes the results of full-scale cyclic tests of weak-axis steel moment connections. A Weak-axis steel moment resisting connection commonly found in building frames is the web axis connection. In this type of connection, the beams are attached to the plane of the column web perpendicularly and it tends to bend the column at its weak axis. In this study, some of the fundamental behaviors of beam-to-column connections were examined by changing the connection details as well as comparing them with previous connection details. For this purpose, 2 types if weak-axis steel moment connection full scale specimens are fabricated tested to evaluate the seismic performance.

연관 규칙 탐사를 이용한 수학 교육 성취도 분석

정희택,서정현 여수대학교 2002 論文集 Vol.17 No.-

An evaluation analyzes the accomplishment of an educatee's schoolwork by a curriculum. It is necessary for us to find the way of a course of study for a poor learner by overall evaluation at school. So this study suggests the measure that teacher can analyse a poor learner and apply the way of a course of study by association rule mining.

3차원 터빈 익렬 유동 해석을 위한 격자 형성법

정희택 한국항공우주학회 1995 한국항공우주학회 학술발표회 논문집 Vol.- No.-

가스터빈엔진용 축류압축기의 공력 설계 기법개발 및 적용

鄭喜澤 慶尙大學校生産技術硏究所 1996 生産技術硏究所論文集 Vol.12 No.-

The aerodynamic design system of the axial-flow compressors for the large-scaled industrial gas turbines was developed using the conventional methods. The current design procedure is composed of the four separate program modules; i.e., 1) preliminary design 2) computation of the aero-thermal properties using the streamline curvature method, 3) determination of the blade profiles and 4) the estimation of the full-stage compressors at the off-design conditions. Using this design systems, the aerodynamic design was performed for the six-stage LP compressor for 100 MW class industrial engines. The aero-thermal conditions for the full-stage and full-span blade design was computed and the detail design of the first rotor blade was performed. The LPC engine performance at the variable speedline and flow rates are predicted using the simple meanline stage-stacking methods. In addition, the conceptual design of the LPC components including the inlet flow passage and the exit turning vane to the intercooler was done for the mechanical design as the future work.

시간제약을 고려한 워크플로우 명세의 일관성 검증 및 스케줄링

정희택 여수대학교 1999 論文集 Vol.14 No.2

According to the complication and the extensiveness of an organization, the request for an automated business processing is on the increase recently. In this reason. the research on a workflow management system distinguishing business processing definitions from their executions is made briskly. In this paper, we propose integrity verification and scheduling of workflows with temporal constraints. we suggest a verification method for the integrity that workflow specifications has no contradiction and can be executed. This method presents the conflict contradictions of temporal constraints and dependencies and verify them. Lastly we propose an scheduling method for workflow specifications with temporal constraints. This method composes conflict resolution module, task decision module and task coordination module. Conflict resolution module can detect the correct execution between workflows based on data dependency. Task decision and coordination module enforce the temporal constraints and dependencies using task status.

초등학생들이 사용하는 채팅 언어의 분석

정희택,정영순 한국정보교육학회 2005 정보교육학회논문지 Vol.9 No.1

In this research, we analyze chatting language of elementary school students, present the properties which are a result of this analysis and propose the method to solve it. Analysis on the chatting language considering organic relation of sentences is classified into syntactic, semantic and statistical characteristics. As a result of analysis, new characteristics is discovered writing by the way children pronounce their words, writing by switching the order of syllable's frontal and rear ends, inarticulate conversation of the other man. To minimize language misuse and to establish a chatting culture that is favorable to the development of children's emotional development, we propose the methods of computer system. 본 연구에서는 초등학생들이 사용하는 채팅 언어를 분석하고 이를 통해 발견된 특성을 제시하며, 나아가 이를 해결할 수 있는 방안을 제안한다. 채팅언어의 분석은 문장들 간의 유기적 관계를 고려하여 형식상, 내용상, 통계상의 특성으로 구분하여 분석한다. 분석 결과로 유아발음으로 변형되어 쓰기, 음절의 앞 뒤 바꾸어 쓰기, 상대방이 불분명한 대화와 같은 새로운 특성이 발견되었다. 분석 결과를 통하여 언어의 오용을 최소화하고, 아동의 정서발달에 긍정적인 채팅 문화를 정착시키기 위해 채팅 관련 컴퓨터 시스템적 방안을 제안한다.

터빈 익렬내부의 3차원 압축성 점성 유동장의 수치 해석 ( Numerical Analysis of Three-Dimensional Compressibale Viscous Flowfields in Turbine Cascades )

정희택,백제현 대한기계학회 1991 대한기계학회 춘추학술대회 Vol.- No.-

가스터빈엔진 내부유동장 해석용 계산격자점 생성기법 연구

鄭喜澤 慶尙大學校生産技術硏究所 1997 生産技術硏究所論文集 Vol.13 No.-

Computaional grids used in the solution of the Naveir-Stokes equations for numerical simulation of gas-turbine flow fields are generated such that they are suited both for the geometry complexities and for the flow characteristics. The present grid generation system adopts the multiblock structure based on the structured H-grids. The numerical algorithm adopts the combination of the algebraic and elliptic method to create the internal grids efficiently and quickly. The system consists of four separate modules for blade-geometry modeling and grid generation. The grid generation method generates a series of two-dimensional grids in the blade-to-blade passage to build up the three-dimensional grid. The system input is made of the results of the preliminary design, i.e., flow-path, aerodynamic conditions along the spanwise direction, and the blade profile data. The final grids generated from each module of the system are used as the preprocessor for the performance prediction of the sectional blade, the blade-stacking process and the three-dimensional flow simulation inside the gas-turbine flow passage. For purposes of illustration, the grid generation system is applied to cascade flow simulations of a transonic turbine rotor and aerodynamic design of the LP compressor.