• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.05a
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• pp.140-143
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• 2001

In this paper, a control problem of the Takagi-Sugeno(TS) fuzzy system with time-varying input delay is considered. It is well known that the delay is one of the major sources responsible for the instability of the controlled system. A systematic design technique is developed based on the Lyapunov-Razumikhin stability theorem. A sufficient condition for the global asymptotic stability of the TS fuzzy systems is formulated in terms of linear matrix inequalities (LMIs). The derived condition can deal with any time-varying input delay within the admissible bound. The effectiveness of the proposed controller design technique is demonstrated by a numerical simulation.

• Journal of Information Technology Applications and Management
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• v.17 no.4
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• pp.57-82
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• 2010

Many companies today use information systems to maintain competitive advantage and to give immediate responses to customer requests. Over time, however, many of these companies failed to make the most of such information systems because the users stopped utilizing the system. While many reasons offer explanations to the phenomenon, this study analyzes how usage intention of information system can be enhanced by changing the environment and usefulness of the system from the user's perspective. Active and wide-ranging researches using the Technology Acceptance Model (TAM) have been carried out on an individual's tendency to using new technology. But, many of the studies remain focused on improving user intention by enhancing the ease of use and usefulness of the system under PC applications or Enterprise applications. The personalized intranet system is not only bringing about sweeping changes to a company's information systems environment but also providing users with freedom to design their own working environment, personalization, to Corporate Information Systems (CIS). Results from empirical tests on intranet systems verify that through personalization, a more voluntary information system environment can be created and that by increasing the ease of use and usefulness of the system, users can become more favorable to accepting new technologies and ultimately result in improved usage intention. This study suggests personalization variables and model for implementing a voluntary CIS for information system developers.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.2
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• pp.6-15
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• 2002

Advancement of Web technology has increased the number of web site and user population. Businesses develop Web applications as its core applications to support business transaction though Internet Although a systematic development methodology should be used to develop Web applications, most businesses do not follow a systematic approach. This study shows a systematic development approach for Web-based electronic commerce information systems. Specifically, it shows how to design a conceptual model following a hypermedia application development model RMM(Relationship Management Methodology) and develop a logical database represented in an XML(extensible Markup

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.189-196
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• 1997

The development of computer integrated systems for structural design requires models to describe and organize information and activities involved in design. An entity-based integrated design model involves a number of product and process entities. Product entities and process entities describe design information and design activities, respectively. One type of relationships among entities is interaction relationships, which describe interdependencies among design information. The interaction relationships can be represented as constraints. Types of constraints include demand constraints, dependency constraints, and interaction constraints. The concepts of representing and processing demand constraints in an entity-based integrated design model are presented.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1460-1464
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• 2003

This paper describes the design and implementation techniques of a generic Internet based telerobotic system. The purpose is to make precious technical information and hands-on experience of the authors widely available for the research community. The paper is based on the telerobotics system that the authors recently implemented between KAIST and Saga University, Japan. In its current functionality, two control modes can be exercised; high-level supervisory control, and low-level supervisory control.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.1
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• pp.9-14
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• 2008

This paper presents an observer design methodology for a special class of multi input multi output(MIMO) nonlinear systems. First, we characterize the class of MIMO nonlinear systems with a triangular structure. Also, the observability matrices that plays an important role in proving the convergence of the proposed observer are generalized to MIMO systems. By using the generalized observability matrices, it is shown that under the boundedness conditions of system state and input, the proposed observer guarantees the local exponential convergence to zero of the estimation error.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.3
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• pp.79-86
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• 2006

Especially, MTO(Make-To-Order) companies take collaborative approaches with their partner companies to make low-price products and/or technologically low intensive products. The collaborative approach to manufacturing requires collaboration with partner companies for inventory review, production plan, and manufacturing to fulfill customer's orders. However, frequent changes of partnerships binder partner companies from sharing production information in effective ways since their information systems have different data architectures and platforms. Therefore, it is required flexible and standardized system integration approach fir effective information sharing. This research studies current status and problems of collaborative production system, proposes an architecture for collaborative production systems based on Web Services which is a standard information technology, and discusses expected effects and the vision of Web Services.

• Journal of the Ergonomics Society of Korea
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• v.32 no.1
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• pp.59-68
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• 2013

Objective: The purpose of this paper is to introduce a task complexity model combining task design aspects and complexity dimensions and to explain an approach to identifying and organizing task complexity factors based on the model. Background: Task complexity is a critical concept in describing and predicting human performance in complex systems such as nuclear power plants(NPPs). In order to understand the nature of task complexity, task complexity factors need to be identified and organized in a systematic manner. Although several methods have been suggested for identifying and organizing task complexity factors, it is rare to find an analytical approach based on a theoretically sound model. Method: This study regarded a task as a system to be designed. Three levels of design ion, which are functional, behavioral, and structural level of a task, characterize the design aspects of a task. The behavioral aspect is further classified into five cognitive processing activity types(information collection, information analysis, decision and action selection, action implementation, and action feedback). The complexity dimensions describe a task complexity from different perspectives that are size, variety, and order/organization. Combining the design aspects and complexity dimensions of a task, we developed a model from which meaningful task complexity factors can be identified and organized in an analytic way. Results: A model consisting of two facets, each of which is respectively concerned with design aspects and complexity dimensions, were proposed. Additionally, twenty-one task complexity factors were identified and organized based on the model. Conclusion: The model and approach introduced in this paper can be effectively used for examining human performance and human-system interface design issues in NPPs. Application: The model and approach introduced in this paper could be used for several human factors problems, including task allocation and design of information aiding, in NPPs and extended to other types of complex systems such as air traffic control systems as well.

• International Journal of Control, Automation, and Systems
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• v.3 no.2
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• pp.143-151
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• 2005

This paper considers a robust decentralized $H_\infty$ control problem for uncertain large-scale interconnected systems. The uncertainties are assumed to be time-invariant, norm-bounded, and exist in subsystems. A design method based on the bounded real lemma is developed for a dynamic output feedback controller, which is reduced to a feasibility problem for a nonlinear matrix inequality (NMI). It is proposed to solve the NMI iteratively by the idea of homotopy, where some of the variables are fixed alternately on each iteration to reduce the NMI to a linear matrix inequality (LMI). A decentralized controller for the nominal system is computed first by imposing structural constraints on the coefficient matrices gradually. Then, the decentralized controller is modified again gradually to cope with the uncertainties. A given example shows the efficiency of this method.

• Information Systems Review
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• v.3 no.1
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• pp.205-219
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• 2001