• Journal of Industrial Technology
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• v.19
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• pp.15-23
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• 1999

Active damping system is generally used for the vibration suppression and precise motion control for the flexible structure. This application can be easily found on the space structure and driving mechanism of optical storage devices. Although a control system using the flexible structure has many advantages over using rigid mechanism in driving energy saving, system weights, and etc., more complex and precise control strategies are required. A position control system using flexible structure and the concept of active damper is designed and manufactured, which is driven by slide DC motor and moving coil motor located at the tip of the flexible beam. Dynamic characteristics of this system are investigated by analytic and experimental ways. By the comparison of those two results, a nominal reference model for this system is proposed.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.9
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• pp.1351-1363
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• 1990

In this paper, a reliable control system structured with dual CPU modules and dual I/O modules is implemented as a means of achieving a highly reliable fault tolerant control system. For this, faults in the system modules are first examined, and a fault detection technique consisting of self diagnostic, comparison process, and exception processing is applied. Self diagnostic is used to locate which components in the modules have been failed, while comparison process is to cmpare control outputs computed by both CPU modules and protect the plant from malfunction by blocking failed control outputsin advance. Finally exception processing is used to determine the faults that are not detected immediately by the self diagnostic and comparison process, e.g. bus error processing when acknowledge signal for data transfer is not activeted in the I/O modules. Also reliability analysis is conducted for the discrete time Markov model with dual structure. It is shown quantitatively that the reliability is improved in the control system with dual structure in comparison with a system with single module structure.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.519-526
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• 2003

In this paper, a Fiber Bragg Grating (FRG) sensor system is described and FBGs are well-suited for long term and extremely severe experiments, where traditional strain gauges fail. In the system, a reflect wave-length measurement method which employs a tunable light source to find out the center wave-length of FBG sensor is used. We apply the FBG system to nuclear energy Power Plant for structural integrity test to measure the displacement of the structure under designed pressure and to check the elasticity of the structure by measuring the residual strain. The system works very well and it is expected that it can be used for a real-time strain. temperature and vibration detector of smart structure.

• The Journal of Korea Robotics Society
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• v.17 no.4
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• pp.493-499
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• 2022

This paper presents the design for the kinematic structure of a system for an automatically moored 6000 ton autonomous ship in a port, and the process and results of optimal design for the link cross-sectional shape. We propose an automatic mooring system with a PPP type serial manipulator structure capable of linear motion in the XYZ axis. The mooring force applied by the mooring system was derived with dynamics simulation tool "ADAMS". The design goal is the minimization of the cross-sectional area of the link. Constrains include compressive stress and shear stress. The optimization problems were solved by using the sequential quadratic programing method implemented in the fmincon package. The shape of the cross section was assumed to be rectangle. Through future research, we plan to manufacture automatic mooring system for 6000ton class autonomous ship.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4307-4316
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• 2023

In this paper, modal effective mass for asymmetric fluid-structure interaction system is defined and equations for its calculation is derived. To establish consistency, modal effective mass in symmetric structure only system is briefly reviewed, followed by a definition of the modal effective mass in asymmetric system. The equations for calculating modal effective mass in asymmetric system are derived by utilizing the properties of left and right eigenvectors. To simplify the equations, the assumption is made that the mass matrix is only affected by the fluid. The simplified equation is then compared to the equation already used in ANSYS. Finally, the validity of the modal effective mass definition and derivation in this paper is demonstrated through a simple example.

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.1
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• pp.89-96
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• 2013

This study aims to clarify the transformation of urban spatial structure around old castle in cheong-ju city. The urban spatial structure is composed with road system, block division, and lot system with original cadastral map in 1913 and 2011 GIS. Transformation of road system is classified into control of road line, construction and extension of road. Construction of arterial road was divided into Nam-juro and Mang-sunro with 2 blocks and lot system was destoyed. Transformation of block has not been developed except 4 blocks. The 4 blocks were divided into east-west or north-south direction and became 8 blocks. Transformation of lot system is classified into maintained, subdivided, and destroyed lots in shape and size of lots. Maintained lots were found in large lot in size for public office and park. Subdivided lots were mainly represented with the existing main road, an active alleys, and so on. Destroyed lots by road construction and extension were showed in Nam-juro. Although all these transformations are used to enhance urban spatial structure. The old systems have remained around old castle in cheong-ju city.

• International Journal of Aeronautical and Space Sciences
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• v.7 no.1
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• pp.106-117
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• 2006

The active vibration control of composite shell structure has been performed with the optimized sensor/actuator system. For the design of sensor/actuator system, a method based on finite element technique is developed. The nine-node Mindlin shell element has been used for modeling the integrated system of laminated composite shell with PVDF sensor/actuator. The distributed selective modal sensor/actuator system is established to prevent the effect of spillover. Electrode patterns and lamination angles of sensor/actuator are optimized using genetic algorithm. Continuous electrode patterns are discretized according to finite element mesh, and orientation angle is encoded into discrete values using binary string. Sensor is designed to minimize the observation spillover, and actuator is designed to minimize the system energy of the control modes under a given initial condition. Modal sensor/actuator for the first and the second mode vibration control of singly curved cantilevered composite shell structure are designed with the method developed on the finite element method and optimization. For verification, the experimental test of the active vibration control is performed for the composite shell structure. Discrete LQG method is used as a control law.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.10
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• pp.950-961
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• 2000

The objective of this study is to develop optimal alternative selection model for renewing building equipments system. Cost Breakdown Structure of LCC in HVAC systems are deduced from resonable data and factors. As for Cost Breakdown Structure of LCC in HVAC system, pertinent level, title, CBS number, and block number are determined efficiently. Especially, in addition to current cost factor, it is possible to make Cost Breakdown Structure using present worth method more clear. A model of POWER LCC ver 1.0 used to analyze primary cooling system, heating system, and air conditioning system are POWER LCC ver 1.0_/sub SYSTEM/ : C1+ C2- C3+ C4+ C5+ C6+ C7±C8+ C9- C10/sub -1/+ C10/sub -2/+ C10/sub -3/, and is implemented with consideration of Cost Breakdown Structure and their summation using present-worth method. It is programmed with one of scientific languages, MATLAB 5.3.

• Industrial Engineering and Management Systems
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• v.9 no.3
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• pp.215-226
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• 2010

Since product design strongly depends on the experience and ability of the designers, and a long lead time is required for the product design stage, introducing a support system related to this experience and ability is an effective technique to reduce the lead time. In this paper, an information system is developed to support the development of engineering mechanisms with the evaluation of the assembly process on the basis of the abstract functions required for new products. The developed system is based on a database system involving the following data structure: (1) a hierarchical structure related to information about the product functions, (2) the relationship between the parts and engineering functions and/or mechanisms of products, and (3) the relationship between the parts and manufacturing characteristics. The system stores the relationships between the product functions, structure of parts, and assembly characteristics. This information can then be interactively retrieved using the data structure described in (1), (2), and (3). A procedure for designing new products is proposed that involves using the information about existing products. This paper presents the characteristics of the proposed procedure and the developed information system. In addition, a case study of the redesign of a simple structured robot by using the proposed procedure is discussed.

• Journal of the Korean Society for information Management
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• v.28 no.1
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• pp.145-170
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• 2011

The purpose of this paper is to suggest a pilot model of knowledge organizing system which reflects the knowledge structure of research papers, using a case analysis on the "Korean Research Memory" of the National Research Foundation of Korea. In this paper, knowledge structure of the research papers in humanities and social science is described and the function of the "Korean Research Memory" for scholarly sense-making is analysed. In order to suggest the pilot model of the knowledge organizing system, the study also analysed the relation between indexed keyword and knowledge structure of research papers in the Korean Research Memory. As a result, this paper suggests 24 axioms and 11 inference rules for an ontology based on semantic relation of the knowledge structure.