• Korean Journal of Computational Design and Engineering
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• v.22 no.2
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• pp.129-140
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• 2017

This paper presents a systematic approach for design of timely and proper layouts of a manufacturing system facilitating reconfigurability, referred to as a reconfigurable manufacturing system. A proper methodology for design of a system layout is required for reconfiguration planning - adding or removing machines for supplying the exact capacity needed to fulfill market demands, as well as minimizing the cost of adding new machines. In this paper, theory of constraints is used to make reconfiguration manufacturing systems more cost-effective and efficiency. The proposed approach is validated by using a real industrial case. This paper suggests that the proposed study should be performed concurrently with the design of a new manufacturing system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1270-1273
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• 2004

The mechanism design is synthesis of suitable mechanism which can be output motions about input motions. That has generally two steps which are the type synthesis and the dimensional synthesis. And required mechanism analysis step for confirming middle or final result. The type synthesis is definition of mechanism type which required aim and the dimensional synthesis is calculation of dimension about defined type mechanism. The type synthesis of mechanism is included qualitative design field which isn't defined systematic design method. especially, the most difficult step for mechanism design automation. In this paper proposed the component modular design method which is figured mechanism types automate with component modules using component modular approach. And develop CAD(Computer Aided Program) program for application.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1463-1467
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• 2009

Construction projects are vulnerable to diverse internal and external factors, requiring systematic and consistent performance management along the entire life cycle of a project. In particular, urban renewal projects have a range of performance measures, including policy reconciliation and permits, project development, project financing, design, construction, and occupancy and maintenance. This requires a program-level megaproject approach, which integrates each stage of a project as well as variety of stakeholders' interests in pursuing a project from different perspectives. However, previous research on performance management has focused especially on the limited scopes of factors, including cost, quality, and schedule at the project level or on financial factors at the firm level. Given the lack of current approaches, this study suggests an integrated and systematic performance management scheme to control urban renewal megaprojects at the broadened perspectives of the program level. To this end, this study adopts the balanced scorecard approach and elicits key performance indices associated with various project configurations. Finally, an algorithm is presented for quantitatively assessing the level of performances along whole life cycle of urban renewal megaprojects.

• Computers and Concrete
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• v.6 no.6
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• pp.491-503
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• 2009

This paper presents a design framework developed using axiomatic design (AD) theory that can be applied in the design process of porous concrete. The main contribution of this paper is the definition of an AD framework based on the needs and functional requirements of porous concrete. The framework shows how AD theory can be used to provide guidelines for proportioning and manufacturing porous concrete. The advantage of the AD approach is that it systemizes the way to decouple design parameters and makes designers to think rationally between what we want to achieve and how we propose to satisfy the functional requirements of porous concrete. In this paper, test results of laboratory-size porous concrete specimens under compression were analyzed to evaluate the performance of the porous concrete based on the desired functional requirements.

• IE interfaces
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• v.15 no.2
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• pp.114-125
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• 2002

The objective of this paper is to describe a systematic accident scenario analysis method(SASA) adept at creating accident scenarios for the design of safer products. This approach was inspired by the Quality Function Deployment(QFD) method, which is conventionally used in quality management. In this study, the QFD provides a formal and systematic scheme to devise accident scenarios while maintaining objectivity. SASA consists of three key stages to be broken down into a series of consecutive steps:(1) developing an accident analysis tableau,(2) devising the accident scenarios using the accident analysis tableau,(3) performing a feasibility test, a clustering process and a patterning process, and finally(4) performing quantitative evaluation of each accident scenario. The SASA was applied to a case study of child safety seats. The accident analysis tableau devised 2828(maximum) accident scenarios from all possible relationships between the hazard factors and situation characteristics. Among them, 270 scenarios were devised through the feasibility test and the clustering process. The patterning process reduced them to 29 patterns representative of all accident scenarios. Based on an intensive analysis of the accident patterns, design guidelines for a safer child safety seat were recommended. The implications of the study on the child safety seat case were then discussed.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.161-169
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• 2013

Due to the recent advances in technology, the systems are becoming more demanding in terms of functionality and implementation complexity. Therefore, when system failures are involved in such complex systems, the effects of the related safety issues can also be more serious, thereby causing in the worst case irrecoverable hazards on both human being and properties. This fact can be witnessed in the recent rail systems accidents. In general, the accidents can be attributed to the systematic failure or the random failure. The latter is due to the aging or unsatisfied quality of the parts used in implementation or some unexpected external cause that would otherwise result in accidents whereas the former is usually related to incomplete systems design. As the systems are becoming more complex, so are the systematic failures. The objective of the paper is to study an approach to solving the systematic failure. To do so, at first the system design process is augmented by the functional safety activities that are suggested in the standard IEC 61508. Analyzing the artifacts of the integrated process yields the traceability, which satisfies the requirements for reduction of systematic failure as provided in ISO 26262. In order to reduce systematic failure, the results are utilized in the conceptual design stage of systems development in which systems requirements are generated and functional architecture is developed.

• Journal of the Korean Institute of Intelligent Systems
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• v.2 no.3
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• pp.29-39
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• 1992

We investigate a systematic design procedure of automatic rule generation of fuzzy logic based controllers for highly nonlinear dynamic systems such as an engine dynamic modle. By "automatic rule generation" we mean autonomous clustering or collection of such meaningful transitional relations from one conditional subspace to another. During the design procedure, we also consider optimaly control strategies such as minimum squared error, near minimum time, minimum energy or combined performance critiera. Fuzzy feedback control systems designed by our method have the properties of closed-loop stability, robustness under parameter variabitions, and a certain degree of optimality. Most of all, the main advantage of the proposed approach is that reliability can be potentially increased even if a large grain of uncertainty is involved within the control system under consideration. A numerical example is shown in which we apply our strategic fuzzy controller dwsign to a highly nonlinear model of engine idling speed control.d control.

• Journal of Power Electronics
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• v.9 no.5
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• pp.757-771
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• 2009

This paper proposes a systematic approach to the modeling of the small-signal characteristics of three-phase bridge boost rectifiers under non-sinusoidal conditions. The main obstacle to the conventional synchronous d-q frame modeling approach is that it is unable to identify a steady-state under non-sinusoidal conditions. However, for most applications under non-sinusoidal conditions, the current loops of boost rectifiers are designed to have a bandwidth that is much higher than typical harmonics frequencies in order to achieve good current control for these harmonic components. Therefore a quasi-static method is applied to the proposed modeling approach. The converter small-signal characteristics developed from conventional synchronous frame modeling under different operating points are investigated and a worst case point is then located for the current loop design. Both qualitative and quantitative analyses are presented. It is observed that operating points influence the converter low frequency characteristics but hardly affect the dominant poles. The relationship between power stage parameters, system poles and zeroes is also presented which offers good support for the system design. Both the simulation and experimental results verified the analysis and proposed modeling approach. Finally, the practical case of a parallel active power filter is studied to present the modeling approach and the resultant regulator design procedure. The system performance further verifies the whole analysis.

• Korean Journal of Chemical Engineering
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• v.36 no.3
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• pp.356-367
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• 2019

This work presents an advanced and systematic approach to analytically design the optimal parameters of a two parameter second-order internal model control (IMC) filter that satisfies operational constraints on the output process, the manipulated variable as well as rate of change of the manipulated variable, for a first-order plus dead time (FOPDT) process. The IMC parameters are designed to minimize a control objective function composed of the weighted sum of the error between the process variable and the set point, and the rate of change of the manipulated variable, and to satisfy the desired constraints. The feasible region of the constrained IMC control parameters was graphically analyzed, as the process parameters and the constraints varied. The resulting constrained IMC control parameters were also used to find the corresponding industrial proportional-integral controller parameters of a Smith predictor structure.

• Korean Journal of Computational Design and Engineering
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• v.8 no.2
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• pp.101-108
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• 2003

Presented in this paper is the development of an product cost estimation system at the product design stage. The efficient cost estimation function at the design stage is essential for the cost reduction activities through the entire product life cycle. For this purpose, it is necessary to establish a systematic working procedure, and to develop information system for managing a great deal of production and product-related data required for the cost estimation. The developed system has the capability of estimating a cost of assembly type products as well as unit-item type products. As proposed system is based on the variant approach, it can be used easily at an early design stage without the need for detail design information. Also, this system is integrated with legacy PDM (Product Data Management) and ERP (Enterprise Resource Planning) system for fast. accurate and easy product cost estimation. The estimated cost includes material cost, overhead cost as well as labor cost.