• 전기학회논문지
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• 제59권11호
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• pp.2066-2072
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• 2010

In this paper, a variable structure dynamic output feedback controller with an transformed sliding surface is designed for the improved robust control of a uncertain system under unmatched system uncertainty, matched input matrix uncertainty, and disturbance satisfying some conditions. This paper is extended from the results of the static output feedback VSS in [9]. To effectively remove the reaching phase problems, an initial condition of the dynamic output is determined. The previous some limitations on the dynamic output feedback variable structure controller is overcome in this systematic design. A stabilizing control is designed to generate the sliding mode on the predetermined sliding surface S=0 and as a results the closed loop exponential stability is obtained and proved together with the existence condition of the sliding mode on S=0 for all unmatched system matrix uncertainties. To show the usefulness of the algorithm, a design example and computer simulations are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.211-215
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• 1989

The structure of A matrix of one machine connected to the infinite bus is described for a full model. The A matrix can be partitioned to submatrices which depend on the initial operating point and do not depend on it. When the dynamic properties for several different operating points are desired, those submatrices can be obtained through simple column operations. Furthermore, the elements of A matrix car be directly calculated from the manufacturer's data. RMS quantities of the state variables for the initial operating point are used. This approach can save the labor for calculating the elements of A matrix for the dynamic stability analysis.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.475-478
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• 1998

The matrix hypercube MH(2,n) is the interconnection network which improves the network cost of the hypercube. In this paper, we propose an algorithm for one-to-all broadcasting in the matrix hypercube MH(2,n). The algorithm can broadcast a message to 22n nodes in O(n) time. The algorithm uses the rich structure of the matrix hypercubes and works by recursively partitioning the original matrix hypercubes into smaller matrix hypercubes.

• 대한기계학회논문집A
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• 제22권1호
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• pp.23-32
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• 1998

A shape estimation is needed to control actively a smart structure. A method is, hence, proposed to predict the deformed shape of the structure subjected to unknown external load using the signal from sensors attached to the structure. The shape estimation is based on the relationship between the deformation of the structure and the signal from the sensors. The matrix containing the relationship between the deformation and signal is obtained using fictitious force or eigenvector of global stiffness matrix. Then the deformed shape can be predicted using the linear matrix and signal from sensors attached to the structure. To verify this method, experiment and FEM were performed and it was shown that the shape estimation method based on the fictitious force predicts deflections well and more accurately than that based on eigenvector.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.550-555
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• 2011

Utilizing construction knowledge and experiences in design phase can reduce change orders and improve productivity in construction phase. To do so, information must be made available to the design team in time. Current approaches for effective utilization of constructability knowledge, however, only focus on the formalization of constructability knowledge such as a checklist, which lacks the consideration of the appropriate use at the proper point in time. The inadequate use of constructability knowledge can result in unnecessary reworks. To deal with this problem, the design team needs to know what constructability knowledge is required for specific design activities in the design process. This paper presents a constructability implementation model using the dependency structure matrix (DSM) that focuses on information flows between design activities and constructability knowledge. For this objective, design activities in the design process are modeled in a matrix form based on their dependency. Then, constructability knowledge, which needs to be considered in the design stage, is mapped into activities and incorporated into the matrix, creating Constructability-DSM (C-DSM). Next, the partitioning algorithm is applied to C-DSM for optimal information flow. The Partitioned C-DSM is then analyzed based on the relationship between activities. Finally, the optimal utilization of construction knowledge in the design process is determined by identifying what constructability knowledge is required for each design activity, and how and when it is reflected to design for constructability. Thus, this research can help provide robust control actions to reduce unnecessary iterative cycles in design process for efficient constructability implementation.

• 산업융합연구
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• 제19권3호
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• pp.1-12
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• 2021

매트릭스 조직구조에 대한 실무적 관심이 높지만 사례 및 실증연구는 아직 매우 부족한 편이이다. 본 연구의 목적은 반도체 산업의 매트릭스 조직구조의 문제점을 파악하고 이를 개선할 수 있는 방안을 제시하는 것이다. 또, 매트릭스 조직의 문제점에 대한 직급별 인식차이가 있는지 살펴보고 팀별 인식차이가 있는지도 살펴보고자 한다. 본 연구에서 H사 연구원들을 대상으로 정성적 설문조사를 통해 밝혀낸 반도체 산업의 매트릭스 조직구조의 문제점은 다음과 같다. 연구원들은 차세대 반도체 개발을 위해 높은 전문성 있는 멤버를 참여시킨 매트릭스 조직구조가 필요함에 공감하고 있으며 프로젝트 참여 및 성공의지가 강하다는 것을 알 수 있었다. 하지만, 장비 및 인력이 부족하고 프로젝트 관리자는 물론 프로젝트 구성원들 모두 업무량이 많다는 것에 동의하고 있었다. 개방형 설문에서 연구자들은 '프로젝트관리자 권한 미약', '커뮤니케이션 및 팀워크 문제', '업무우선순위 불명확', '보상제도', '연구인력 및 장비부족'을 지적하였다. 반도체 산업의 매트릭스 조직구조의 강점과 약점으로부터 이를 해결하기 위한 개선방안도 도출하였다.

• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.283-291
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• 2005

Accurate seismic analyses of large deformable moving structures are still unsolved problems in the field of earthquake engineering. In order to analyze these problems, the nonlinear finite element method formulated by the absolute nodal coordinate approach is noticed. Because, this formulation has several advantages over the standard procedures on mass matrix, elastic forces and damping forces in the case of large displacement problems. But, it has not been fully studied to build frame structure models by using beam elements in the absolute nodal coordinate formulation. In this paper, we propose the connecting method of the beam elements formulated by the absolute nodal coordinate. The coordinate transformation matrix of this element is introduced into the frame structure. This beam element has the characteristic that the mass matrix and bending stiffiness matrix are constant even if in the case of large displacement problems, and this characteristic is being kept after the transformation. In order to verify the proposed method, we show the numerical simulation results of frame structures for a vibration problem and a large displacement problem.

• 한국주조공학회지
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• 제19권1호
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• pp.77-83
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• 1999

Strip casting process, a new casting technology which makes thin strip of $0.5{\sim}5\;mm$ thickness directly from molten metal, has been dramatically developed for past 10 years and faced commercialization in the case of STS304 strip. In this study, ductile cast iron strip which is 1.1 mm thick and 100 mm wide is manufactured by the twin roll strip caster. Graphite and matrix structure of the strip can be controlled through heat treatments and the mechanical properties are examined. The microstructure of the as-cast strip consists of cementite and pearlite. Especially the equiaxed crystal zone of pearlite exists in the center region of the thickness due to the characteristics of the strip casting process. Matrix structure can be transformed into fully ferrite or ferrite/pearlite mixed structures by the different graphitization heat treatments. The heat-treated strip with ferrite/pearlite matrix structure showed higher hardness and tensile strength than that with full ferrite matrix structure.

• 대한인간공학회지
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• 제26권3호
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• pp.111-115
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• 2007

Design equations for anthropometric product design are developed by considering the geometrical relationships of design dimensions and anthropometric dimensions. The present study applied the design structure matrix (DSM) method to the development of design equations for a computer workstation, and compared design values from the design equations with corresponding design values of ergonomic recommendations and existing products. The relationships between design dimensions (e.g., legroom and worktable) were analyzed by a DSM, and then the application order of design equations (e.g., seatpan, backrest, armrest, legroom, and worktable in descending order) was determined. Next, design equations were developed by analyzing the geometric relationships between computer workstation design dimensions and anthropometric dimensions. Finally, design values for a computer workstation were determined by considering a standard posture defined and representative human models (5th, 50th, 95th %ile). The design values calculated using the design equations were similar with those of ergonomic recommendations found in literature and two commercial products measured in the study; however, some design values (e.g., seatpan height) were different due to discrepancy in standard posture. The DSM method would be utilized to systematically analyze the relationships between design dimensions for anthropometric product design.

• 대한토목학회논문집
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• 제33권1호
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• pp.337-346
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• 2013

플랜트 설계는 매우 다양한 공학 분야가 참여하는 고도로 복잡한 시스템이다. 이 방대한 시스템에 관여된 각 서브시스템은 각기 다른 서브시스템과 수시로 정보를 주고 받으며 작업을 반복하게 되는 복잡한 관계를 형성한다. 이런 복잡한 프로세스에서 체계적인 설계관리는 성공적인 플랜트 설계를 위한 필수적인 요건이다. 이에 본 연구에서는 Design Structure Matrix를 이용하여 플랜트의 최적 설계 협업 체계를 도출하였다. 이를 위해 전문가 설문 및 워크샵을 수행하여 플랜트 설계의 주요 업무, 설계 서브시스템, 설계요소, 관련설계요소, 그리고 그들간의 관계를 파악하였다. 효율적인 분석을 위해 Visual Basic Application과 Matlab을 이용하여 자동화된 분석 프로그램을 개발하였다. 제안된 방법과 프로그램을 소각로 설계 시스템에 적용한 결과 유효한 주요 반복작업 그룹들을 도출할 수 있었다. 도출된 결과물은 설계 협업 전략 수립에 유용하게 활용될 수 있을 것으로 사료된다.