• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.5
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• pp.140-150
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• 2003

Observational methods such as the Asaoka's method and the hyperbolic method are widely applied on the settlement analysis using observed settlement. The most unreliable aspects in those methods is arose from the subjective discretion of initial non-linearity on linear regression. The initial non-linearity is inevitable due to the settlement behaviour itself. Therefore an objective method is essential to achieve more reliable results on settlement analysis. It was found that the initial non-linear data are statistical outliers. New automation algorithms of the hyperbolic and the Asaoka's method were developed based on outlier detection method. The methods are a successive detection of outliers and a searching method of suitable hyperbolic range for the Asaoka's and the hyperbolic method respectively. Applicability of the algorithms was verified through case studies.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.12
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• pp.121-128
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• 2000

The scope of this paper is focused to the systems which have the time period and they should be necessarily studied in the sense of stability and design method of controller to stabilize the orignal unstable systems. In general, the time periodic systems or the systems having same motions during certain time interval are easily found in rotating motion device, i.e., satellite or helicopter and widely used in factory automation systems. The characteristics of the selected dynamic systems are analyzed with the new stability concept and stabilization control method based on Lyapunov direct method. The new method from Lyapunov stability criteria which satisfies the energy convergence is studied with linear algebraic method. And the numerical procedures are developed with computational programming method to apply to the practical linear periodic systems. The results from this paper demonstrate the usefulness in analysis of the asymptotic stability and stabilization of the unstable linear periodic system by using the developed simulation procedures.

• Journal of Power Electronics
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• v.14 no.3
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• pp.549-563
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• 2014

In this paper, the speed regulation problem of permanent synchronous motor (PMSM) systems under the vector control framework is studied. A model reference adaptive controller (MRAC) based on the Lyapunov stability theory is first designed. Since the standard MRAC method provides poor disturbance rejection performance in the case of strong disturbances, a composite control method which combines the MRAC method and the disturbance estimation method, called the MRAC+ESO method, is proposed. An extended state observer (ESO) is introduced to estimate the lumped disturbances. The obtained estimated value acts as a feedforward compensation term to the MRAC controller. A stability analysis of the composite control method is given. Simulation and experimental results are presented and compared to show the effectiveness of the proposed control method.

• International Journal of Control, Automation, and Systems
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• v.1 no.3
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• pp.395-400
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• 2003

A quantitative performance evaluation of a robot teaching method using a force/moment direction sensor is presented. The performance of the teaching method using the force/moment direction sensor is compared with the conventional teaching pendant method. Two types of teaching tasks were designed and the teaching times required to complete the teaching tasks were measured and compared. Task A requires a teaching motion that involves four degrees of freedom motion. Task B requires a teaching motion that involves six degrees of freedom motion. It was found that, by using the force/moment direction sensor method, the teaching times were reduced by 25% for Task A and 45% for Task B compared to the teaching pendant method.

• International Journal of Control, Automation, and Systems
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• v.1 no.1
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• pp.93-100
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• 2003

Accuracy in maneuvering target tracking using multiple models relies upon the suit-ability of each target motion model to be used. To construct multiple models, the interacting multiple model (IMM) algorithm and the adaptive IMM (AIMM) algorithm require predefined sub-models and predetermined acceleration intervals, respectively, in consideration of the properties of maneuvers. To solve these problems, this paper proposes the GA-based IMM method as an intelligent tracking method for a maneuvering target. In the proposed method, the acceleration input is regarded as an additive process noise, a sub-model is represented as a fuzzy system to compute the time-varying variance of the overall process noise, and, to optimize the employed fuzzy system, the genetic algorithm (GA) is utilized. The simulation results show that the proposed method has a better tracking performance than the AIMM algorithm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.19-25
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• 2010

Most faults are single-phase-to-ground fault in ungrounded system. The fault currents of single-phase-to-ground are much smaller than detection thresholds of measurement devices, so detecting single-phase-to-ground faults is difficult and important in ungrounded system. The protection coordination method using SGR(Selective Ground Relay) and OVGR(Overvoltage Ground Relay) is generally used in ungrounded system. But this method only detects fault line and it has the possibility of malfunction. This paper proposed to advanced protection coordination method in ungrounded system. The method just using zero-sequence current can detect fault line, fault phase, fault section at terminal device. The general protection method is used to back up protection. In the case study, the proposed method has been testified in demo system by Matlab/Simulink simulations.

• Journal of Information Technology Applications and Management
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• v.15 no.1
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• pp.271-282
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• 2008

Database administrators are demanded to acquire much knowledges and take great efforts for keeping consistent performance in system. Various principles, methods, and tools have been proposed in many studies and commercial products in order to alleviate such burdens on database administrators, and it has resulted to the automation of DBMS which reduces the intervention of database administrator. This paper suggests a resource selection method that estimates the status of the database system based on the workload characteristics and that recommends tuneable resources. Our method tries to simplify selection information on DBMS status using data-mining techniques, enhance the accuracy of the selection model, and recommend tuneable resource. For evaluating the performance of our method, instances are collected in TPC-C and TPC-W workloads, and accuracy are calculated using 10 cross validation method, comparisons are made between our scheme and the method which uses only the classification procedure without any simplification of informations. It is shown that our method has over 90% accuracy and can perform tuneable resource selection.

• Korean Journal of Computational Design and Engineering
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• v.4 no.1
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• pp.19-31
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• 1999

One of the non-photorealistic rendering method, a drawing technique which uses only fine curves and dashed line, is widely employed in an knots and post stamps printing. Engraving of the curves and lines are traditionally performed by human engravers which leads to low productivity in printing preparation. As an effort to improve productivity and quality, a drawing automation method which can easily produce a portrait composed of vector data for laser or chemical engraving is proposed. The method shows that it is possible to draw a portrait by controling the width and length of predefined fine lines according to the gray scales a the end points of each fine lines. A gradually controled weighting factor method is proposed in addition to the author previous works to prevent undesirable boundaries in an identical texture region. User interface functions of a commercial CAD system are heavily employed to exploit the presented method.

• International Journal of Control, Automation, and Systems
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• v.5 no.2
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• pp.200-207
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• 2007

The passive direction finding cross localization method is widely adopted in passive tracking, therefore there will exist masses of false intersection points. Eliminating these false intersection points correctly and quickly is a key technique in passive localization. A new method is proposed for passive locating and tracking multi-jammer target in this paper. It not only solves the difficulty of determining the number of targets when masses of false intersection points existing, but also solves the initialization problem of elastic network. Thus this method solves the problem of multi-jammer target correlation and the elimination of static false intersection points. The method which dynamically establishes multiple hypothesis trajectory trees solves the problem of eliminating the remaining false intersection points. Simulation results show that computational burden of the method is lower, the elastic network can more quickly find all or most of the targets and have a more probability of locking the real targets. This method can eliminate more false intersection points.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.1
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• pp.19-34
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• 1997

The goals of this study are to suggest the guidance for automated clothing manufacture by analysis the technology of the automated manufacturing facilities and to propose how improve the efficiency of the production planning and management for automated clothing manufacture In this study, the research about the automated clothing manufacturing machines and the analysis about the modules and functions of apparel information systems were performed. In order to understand the factory automation of the larger clothing firms, the case study method was used. The case study samples were 3 clothing firms. The results and suggestions are as follows: 1. An information technology for automated clothing manufacture has enabled the computer integrated manufacturing system to connect production planning and management part with each work station on the factory floor. 2. The apparel information system to integrate and manage manufacturing informations from each workstation and the apparel CAD system are used in the department of production planning. At the cutting room, there are automated manufacturing machines like an automatic spreading system and an automatic cutting system. Sewing room has the computer controlled unit production system and semi-automated sewing machines. In addition, in the finishing room, an automatic packing machine and a press system are used and besides a warehousing system has been developed. Considering these available technology, for better product efficiency, it is necessary to consider and utilize the specific character of these automatic manufacturing machines and computer system whether they proper to each product style. 3. Most of the clothing manufacturers are in the stage of semi-automated manufacture. In order to improve the manufacturing environment, it is needed to gradual procedure of manufacturing automation with considering the firm's financial condition, existing facilities and staffs operating machines. The case study sample firms are in the high degree of manufacturing automation. They can accomplish the flexible manufacturing system to link the information system with each work station menufacturing system by computerized control. For the case of the firm having already used the computer integrated manufacturing and managing system, it is necessary that the function to deal with drawing information is added to the retaining module of the apparel system.