• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.102-106
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• 1997

Grinding has difficulty in satisfying the qualitative knowledge based on the skilled expert as well as quantitative data for all user. Design of grinding database is based on the frame-based model for utilizing the empirical and qualitative knowledge. Inthis paper, basic strategy to develop the grinding database by frame-based model, which is strongly dependent upon experience and intuition, frame-base model, which is strongly dependent upon experience and intuition, is described. Design of grinding database is based on the frame-based model for utilizing the ambiguous knowledge and inference is accomplised by the object-oriented paradigm system.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.107-114
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• 2002

As many software tools are used for managing construction projects, integration of their data and information is gradually becoming critical. Focusing on the integration of design and scheduling data, a generic scheduling information model is designed through this research, with appropriate consideration for past research results on construction information model and also object oriented CAD technology. In order to test the practical usage of this model, a small prototype system which can derive schedule information from the design information is implemented.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.12a
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• pp.769-781
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• 1999

Manufacturing systems are usually large, complex, and concurrent in nature that makes it difficult to model and simulate the behavior in advance. The paper proposes an approach, called OPNets, for modeling and validating manufacturing systems. The approach is based on object-oriented high-level Petri nets in which modeling components of Petri net are constructed into object hierarchy. The objects communicate with each other by passing messages. To enhance the reusability and maintainability, a system are developed by object hierarchy. Inheritance among object hierarchy is also supported in OPNets. The modeling scheme of OPNets tries to resolve the complexity problems of Petri net.

• Journal of Ocean Engineering and Technology
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• v.15 no.4
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• pp.108-114
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• 2001

Petri nets have been introduced as a powerful analyzing and design tool for the discrete systems such as sequential control systems. However, one of the important problems in its applications is that the model can be analyzed hardly when we deal with large scale systems because of increase of the number of Petri net components. To overcome this problem, some methods for dividing or reducing of Petri net have been suggested. In this paper, an approach for hierarchical expression of Petri net based on Sequential function Chart(SFC) and Bottom Up oriented Mehodology(BUM) is proposed. Especially, some definitions and rules are defined in order to divide and compose sub Petri nets. A measuring tank system will be described as a typical kind of discrete systems and modeled by some sub Petri nets based on the SFC and BUM by the proposed method in this paper.

• Journal of Electrical Engineering and Technology
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• v.6 no.2
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• pp.226-232
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• 2011

The $H_{\infty}$ approach, adopted in this paper, is based on loop shaping using a normalized coprime factor combined with a field-oriented control to control induction motor. We develop two loops. The first one, the inner loop, controls the stator current by $H{\infty}$ controller in order to obtain good performance. The second loop, the outer one, guarantees stability and tracking performance of speed and rotor flux using a proportional integral controller. When the rotor flux cannot be measured, we introduce a flux observer to estimate the rotor flux. Simulation and experimental results are presented to validate the effectiveness and the good performance of this control technique.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.33.1-35
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• 2000

Na-K-Nb system showed a number of ferroelectric phases in bulk ceramic. [001]-axis oriented single-phase $Na_{0.5}/K_{0.5}NbO_3$(NKN) thin film have been grown on $LaA1O_3$substrates using KrF excimer laser. X-ray diffraction $\theta$-2$\theta$ scan, rocking curves, and $\varphi$ scan data evidence highly c-axis oriented along the [001] direction.

• IE interfaces
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• v.18 no.1
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• pp.1-9
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• 2005

A new logistics concept is needed through the sharing information between suppliers and consumers, which maximizes the customers service and its flexibility by changing functional- oriented to process-oriented. As in many other industries, communication and data manipulation technology have led to systematical change to the logistics industry. One of the biggest changes of the industry that lies ahead is Consolidated Transportation. To improve this systematically false logistical environment, developing an integrated logistics information system with consolidated transportation, framework, standardization, and data integration is essential. However, no party outstands as the leading party for nationwide improvement of logistics, nor does the right analysis and design for it. Therefore, successful nationwide logistics model is yet to exist. This paper provides individual parties, which consider efficient consolidated transportation as their business models, with instructions for logistics information system so that they could be competitive in the market. It also helps companies collect user requirements for efficient consolidated transportation, and utilize it for its development. Finally, this paper extracts the design of algorithm for the efficient consolidated transportation.

• Journal of Advanced Marine Engineering and Technology
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• v.19 no.3
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• pp.91-98
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• 1995

To control speed or torque of induction motors, scalar control method that regulates the value of stator current had been used conventionally. But, vector control method which contrls the direction and the value of stator current at the same time has been introduced lately and employed widely. This paper describes comparative analyses of above two methods by computer simulation. As a result of the simulation, both methods showed good responses for high speed, but, vector control method characterized much better performance for low speed and sinusoidal input.

• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.3
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• pp.13-26
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• 1999

Recently, information technology and information system(IS) are rapidly diffused throughout the world. In the global competitive environment, the success of IS becomes the important one among the critical success factors(CSF) of the firm. For achieving it, the firm must continually involve itself in the quality evaluation and improvement of IS. The quality concept was changed into the customer-oriented quality one. There is no exception to the quality of IS. In the past, IS quality was determined by the IS developer or IS department offering service. Now it is evaluated by the user of IS service, and then the customer-oriented user satisfaction becomes an important issue. The purpose of this study is to develope the total quality evaluation model of IS through TQM approach. First, all success factors of the domestic IS are extracted from the foreign and domestic literatures of IS success factors contained the technical and behavioral aspects. And the extracted factors are classified with evaluation levels for quality evaluation and developed into a total quality evaluation model. Finally the model usefulness is analyzed.

• Korean Management Science Review
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• v.23 no.3
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• pp.119-132
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• 2006

Since the guaranteed service quality(QoS) is spotlighted as a strategic competitive tool to Broadband Convergence Network(BcN) service providers, many scholars have dealt with QoS issues in the BcN environment. However, just a few researchers focus on end-users and most are lean toward service providers or technology itself. In this paper, therefore, we investigated how end-users could measure service quality in the BcN environment, and moreover, proposed the end-user oriented measurement guideline for BcN QoS. Through literature review and two surveys, four QoS dimensions and nineteen measurement items were derived from end-user's perspective. proposed QoS dimension and items would be utilized as meaningful tools for future BcN service.