• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.73-78
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• 1999

This paper presents an effective construction method of adaptive multiple control systems utilizing some knowledge upon the plants. The adaptive multiple control system operates plants un-der widely changing environmental conditions. The adaptive multiple control system is composed of a family of candidate controllers together with a supervisor. The system does not require any identification schemes of environmental conditions. Monitoring outputs of the plant, the supervisor switches from one candidate controller to another, The basic ideas of adaptation are as follows: (1)each candidate controller is prepared for each environmental condition in advance; (2)the supervise. applies a sequence of speculative controls to the plant with candidate controllers just after the start of control or just after the detection of a change in the environmental condition. Each candidate controller can keep the system stable during one-step period of the speculative control and the most appropriate candidate controller for the environmental condition to which the system is exposed can be selected before the last trial of speculative control step comes to an end. We proposed a construction method of adaptive multiple control system without any knowledge of plant dynamics and applied the method to a cart-pole balancing problem and a vehicle anti skid braking system. In real applications, as we can often easily obtain a piece of knowledge upon plant dynamics beforehand, we intend to extend the method such that multiple control systems can be efficiently designed using the knowledge. We apply the new idea to the cart-pole balancing problem with variable length of the pole. The simulation experiments lead us to the conclusion that the new attempt can reduce the manpower to design the candidate controllers for adaptive multiple control systems.

• KIEAE Journal
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• v.10 no.4
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• pp.29-37
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• 2010

The industrialized countries have promoted the rehabilitation of existing housing units as a national agenda, such as green policies, whereas korea, although having a housing stock as huge as that of world countries, have focused on the growth of housing by constructing new units rather than rehabilitating existing ones. Today, it has been so long since many multiple dwellings in Seoul and in the vicinity of Seoul were constructed. There were, however, very few political efforts to encourage the rehabilitation of housing. Today, substantial time has passed since multiple dwellings in Seoul and the first-stage new cities such as Bundang and Ilsan were constructed. What is required to maintain the quality of the existing housing and use it with safety is to promote the engineer of maintenance for multiple dwellings to work the maintenance of existing multiple dwellings. The objective of this study is to compare and analyze the maintenance qualification system of multiple dwellings of Japan, and then to propose to raise engineers of maintenance for multiple dwellings in korea.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.447-450
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• 2009

In this paper, binary pulse-antipodal modulation (2PAM) direct-sequence (DS) ultra-wideband (UWB) system is applied to multiple input multiple output (MIMO) system using vertical bell lab layered space-time (V-BLAST) structure to achieve high-data-rate communications over indoor wireless channels. The relationship between antenna dimension and BER performance of 2PAM DS UWB MIMO system is discussed. In the receiver of UWB-MIMO system, various MIMO detection algorithms such as zero-forcing (ZF), ZF-ordered successive interference cancellation (OSIC), minimum-mean-square-error (MMSE), MMSE-OSIC and maximum likelihood (ML) are comparatively studied.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.28 no.1
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• pp.55-63
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• 2005

This paper is to analyze the travel distance and the transport size of the vehicle when the AGV carries multiple-load in the tandem automated guided vehicle systems. The size of multiple-load represents the number of load that the AGV can carry simultaneously. The AGV can carry simultaneously multiple-load that load types are different. The transport system of the manufacturing system is a tandem configuration automated guided vehicle system, which is based on the partitioning of all the stations into several non-overlapping single closed loops. Each loop divided has only one vehicle traveling unidirectionally around it. The AGV of each loop has to have sufficient transport capacity that can carry all loads for given unit time. In this paper, the average loaded travel distance and the size of feasible multiple-load of the vehicle are analyzed. A numerical example is shown.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.115-125
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• 2005

This paper discusses how to effectively design a next-generation wireless communication system that can possibly provide very high data-rate transmissions and versatile quality services. In order to accommodate the sophisticated user requirements and diversified user environments of the next-generation systems, it should be designed to take an efficient and flexible structure for multiple access and resource allocation. In addition, the design should be optimized for cost-effective usage of resources and for efficient operation in a multi-cell environment. As orthogonal frequency division multiple access (OFDMA) has turned out in recent researches to be one of the most promising multiple access techniques that can possibly meet all those requirements through efficient radio spectrum utilization, we take OFDMA as the basic framework in the next-generation wireless communications system design. So, in this paper, we focus on introducing an OFDMA-based downlink system design that employs the techniques of hybrid multiple access (HMA) and frequency group (FG) in conjunction with intra-frequency group averaging (IFGA). The HMA technique combines various multiple access schemes on the basis of OFDMA system, adopting the multiple access scheme that best fits to the given user condition in terms of mobility, service, and environment. The FG concept and IFGA technique help to reduce the feedback overhead of OFDMA system and the other-cell interference (OCI) problem by grouping the sub-carriers based on coherence band-widths and by harmonizing the channel condition and OCI of the grouped sub-carriers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.12
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• pp.774-776
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• 2014

In this paper, we propose a multiple dual-polarized antenna system for multi-user transmission in line-of-sight (LoS) dominant channel environments. By exploiting space and polarization resources efficiently, the proposed system achieves a higher sum rate than the existing multi-user multiple input multiple output (MU-MIMO) system with uni-polarized antennas.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.116-125
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• 2014

In this paper, we investigate an inventory and production system in a three-layer supply chain system involving a single supplier, single manufacturer and multiple retailers. Earlier study in this type of supply chain only consider a single raw material in order to produce single item, but we consider raw materials in order to produce multiple items. It is assumed that the cycle time at each stage is an integer multiple of the adjacent downstream stage. We develop an iterative solution procedure to find the order quantity for the multiple items and raw materials that minimizes the supply chain-wide total cost per unit time of the supplier and manufacturer's raw materials ordering and holding, setup and finished items holding, the retailer's ordering and inventory holding. Numerical examples are presented to show that the proposed heuristic gives good performance.

• Structural Engineering and Mechanics
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• v.6 no.1
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• pp.77-93
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• 1998

Some design formulas and design procedures for single and multiple tuned liquid column dampers (TLCDs) are proposed in this study. Previous studies show that if the properties of the TLCD system are properly selected then the TLCD could be as effective as the traditional tuned mass dampers. In addition, the TLCD system offers advantages such as flexibility in terms of installation, little maintenance required, and potentials for multiple usage, etc., which are incomparable by other mechanical types of dampers. In this paper, a set of optimal properties such as length and head loss of a TLCD system are derived under the assumption that the building vibrates in a dominate mode and is subjected to Gaussian white noise excitation. A design procedure for a single TLCD system will be illustrated and discussed. Due to the nonlinearity in the damping term, the TLCD system is sensitive to the loading intensity. This loading sensitivity could limit the application range of the TLCD system. It will be shown in this paper that such a nonlinear effect can be reduced by using multiple TLCDs. As a demonstrative example, the control effects on a flexible building modeled as a single degree-of-freedom system subjected to white noise excitation will be analyzed and discussed using single or multiple TLCDs.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.8
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• pp.673-679
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• 2004

In this paper, we develop the displacement measurement system of multiple moving objects based on image processing techniques. The image processing method adopts inertia moment theory for obtaining the centroid measurement of the targets and basic processing algorithm of gray, binary, closing, labeling and so on. To get precise displacement measurement in spite of multiple moving targets, a CGD camera with zoom is used and the position of camera is changed by a pan/tilt system. The fiducial marks on the fixed positions are used as the sensing points for the image processing to recognize the position errors in direction of XY-coordinates. The precise alignment device is pan/tilt of XY-type and the pan/tilt is controlled by DC servomotors which are driven by a microprocessor. Morover, the centers of fiducial marks are obtainted by an inertia moment method. By applying the developed precise position control system for multiple targets, the displacement of multiple moving targets are detected automatically and are also stored in the database system in a real time. By using database system and internet, the displacement datum can be confirmed at a great distance and analyzed. Finally, the effectiveness of developed system is shown in experimental results and realized the precision about 0.12[mm] in the position control of XY-coordinates.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5A
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• pp.494-499
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• 2008

In this study, a Software Defined Radio(SDR) technology-based digital filtering technique applicable to a multiple channel processing system such as a wireless mobile communication system using Code Division Multiple Access(CDMA) technology is proposed. The technique includes a micro-processor to redesign Finite Impulse Response(FIR) filter coefficients according to specific system information and to download the filter coefficients to one digital Band Pass Filter(BPF) to reconfigure another system. The feasibility of the algorithm is verified by implementing a multiple channel signal generator that is reconfigurable to other system profiles, including those for a CDMA system and a WCDMA system on identical hardware platform.