• Design & Manufacturing
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• v.2 no.6
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• pp.33-37
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• 2008

Almost all injection molds have multi-cavity, which are designed with geometrically balanced runner system in order to made filling balance between cavity to cavity during injection molding. However, filling imbalance has been existed in the geometrically balanced runner system. In this study, we made an experiment and investigated that are filling balanced according to material. Also, in case of filling imbalance was occurred, we conducted experiments in order to find out difference of cavity pressure with cavity pressure sensor. When filling imbalance was occurred between cavity to cavity, we investigated the filling imbalance and pressure differences by computer-aided engineering(CAE).

• Journal of the Korean Operations Research and Management Science Society
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• v.19 no.2
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• pp.57-73
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• 1994

KADS is currently a best known methodology for expert system development is Europe. KADS world sees the expert system development as a modeling activity and uses models to control complexity of the development process. Four layers KADS expertise model is used to describe expert knowledge. But this expertise model in high abstraction level is conceptual and not formalized. This paper has formalized KADS expertise model using set theory and mathematical semantics combined in order to reduce the ambiguity of informal models of expertise, provide a precise means of communication about the model of expertise and point out incompleteness and inconsistency of the model of expertise. Instead of first order predicate calculs, set theory and mathematical semantics are used because they are a more general and have compositive quality.

• Design & Manufacturing
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• v.8 no.2
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• pp.50-55
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• 2014

Recently, semi-stack mold have been developed for satisfying the various elements required in the mold industry. The mold is possible using with general-purpose injection molding machine by weight reduction through the improvement of the mold structure. In order to do that, tension core, spiral cooling system and half runner system were applied. It is effective for increased productivity and decreased of loss to the materials. However, the mold is required the filling balance in order to improve the quality and efficiency. Thus this study performed that optimum design and analysis of semi-stack mold for filling balance.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.11
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• pp.907-912
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• 2005

In this paper, we consider the problem of designing sliding surfaces fur a class of dynamic systems with mismatched uncertainties in the state space model. In terms of LMIs, we give necessary and sufficient conditions fir the existence of a linear sliding surface such that the reduced order sliding mode dynamics is asymptotically stable and completely independent of uncertainties. We parameterize all such linear sliding surfaces by using the solution to the given LMI conditions. And, we consider the problem of designing linear sliding surfaces guaranteeing pole placement constraints or $H_2/H_infty$ performances. Finally, we give a design example in order to show the effectiveness of our method.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.11
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• pp.1095-1099
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• 2004

In this paper, a novel sliding surface is proposed to guarantee that the sliding mode controller for a second order system produces a control signal whose magnitude is always within the bound of input saturation. The proposed sliding surface uses a time-varying function, and its time derivative works to make a control signal within the bounds of input saturation. Simulation results are presented to show the effectiveness of the proposed method.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.2
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• pp.28-36
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• 1996

By utilizing the interinsic structure of the underlying continous-time nonlinear system, one can design an approximate sampled-data observer improved with respect ot the sampling-time for the systems. In this paper, we characterize the conditions for the solvability of the improved approximate sampled-data nonlinear observer design problem. In particular, it is shown that when the dimension of the state space is two, the nonlinear systems for which it is possible ot desing 3rd or higher order approximate sampled-data nonlinear observer are locally state-equivalent to an observable bilinear system. The practical implication is that seeking higher order approximate sampled-data nonlinear observer for nonlinear systems is very restricted.

• Journal of The Korean Association of Information Education
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• v.2 no.1
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• pp.138-161
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• 1998

This research addresses to establish a systematic approach to design a standard Hangul code system for educational purposes in development of CAI courseware using Korean, English, and Chinese characters, which requires data exchanges and database construction. In this paper, types of Korean alphabetic code systems already in use, their representational environments and consonant/vowel order have been studied and analysed. This paper presents the requirements that the hangul code system for educational purpose needs to obtain. First, it should be able to represent all contemporary as well as ancient Korean alphabets. Second, character elements should be separable. Third, consonant/vowel order should be determined to easily retrieve and exchange data. Lastly, the code should maintain compatibility with other national codes and provide uniqueness of user-defined character codes.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.2
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• pp.63-71
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• 1985

The existing methods of pole assignment were reserved in this paper, a digital control method for MIMO dynamic systems was developed based on pole assignment using I/O delay. The underlined concept of the derived control law was that the poles corresponding to the order of a system can be assigned on the desired positions via output delay, and the poles of the order incrememted by output delay were forced to be placed on zero positions by way of input delay when applied to an actual MIMO system, the present scheme was shown to be more effective than the conventional state feedback scheme with observer in that the former was simpler than the latter, while they performed well.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.242-246
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• 2010

To determine the trajectories and the impact of rain drops on the facade of a tall building, a particle tracking method is employed form steady state simulation of turbulent flow around the building. The simulation is performed for the upper part of the building comprising a detailed louver system. Rain is trapped at relative high rates on the roof and the penthouse, with Local Intensity Factors (LIF's) of the order of 1. The upper parapets and upper floors get a fair amount of wetting with LIF's of the order of 0.6. The wetting decreases downwards reaching values of 0.2 to 0.25 at the level of the louver system.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1032-1036
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• 1990

This paper describes a system which enables a real-time measurement of 2-D water flow field. One distinctive feature of our system is that velocity vectors of water flow are obtained from the movement of tracer particles at video rate. In order to enable a fast measurement a real time video processor and two Digital Signal Processor(TMS32OC25) are employed. The real-time video processor extracts contours of tracer particles in order to reduce the amount of image data to be processed. And two DSP(Digital Signal Processor) analyse the correlation of every tracer paticle in the consecutive two images to obtain the velocity distribution of water flow.