• Journal of Power System Engineering
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• v.5 no.4
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• pp.82-89
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• 2001

To design a structural or a mechanical system with the best performance, the main procedure of a typical design usually consists of repeated modifications of design parameters and the investigation of the system response for each set of these parameters. But this procedure requires much time, effort and experience. Sensitivity analysis can provide systematic information for improving performance of a system. The author has studied on the development of the structural analysis algorithm and suggested recently the transfer stiffness coefficient method(TSCM). This method is very suitable algorithm to a personal computer because the concept of the TSCM is based on the transfer of the nodal stiffness coefficients which are related to force and displacement vectors at each node. In this paper, a new sensitivity analysis algorithm using the concept of the TSCM is formulated for the computation of state variable sensitivity in static problems. The trust of the proposed algorithm is confirmed through the comparison with the computation results using existent sensitivity analysis algorithm and reanalysis for computation models.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.9
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• pp.1162-1170
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• 1995

In this paper, we present a message transfer scheme for efficient message passing in the hierarchically structured multiprocessor computer SPAX(Scalable Parallel Architecture computer based on X-bar network). The message transfer scheme provides interface not only with operating system but also with end users. In order to transfer two types of control message and data message efficiently, it supports both of memory-mapped transfer and DMA-based transfer. Dual-port RAMs are used as message buffers, and control and status registers provide efficient programming interface. Interlaced parity scheme is adopted for error control. If any error is detected at receiving node, errored packet is resent by sender according to retry mechanism. In conjunction with retry mechanism, watchdog timers are used to protect infinite waiting and repeated retry. The proposed message transfer scheme can be applied to input/output nodes and communication connection nodes as well as processing nodes in the SPAX.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.286-286
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• 2000

We consider a negative unity feedback control system in which Che PIO, PI, PD or P controller and a transfer function having only poles are in cascade, We define the notion of the structural polynomial which means that there exists a subdomain of the coefficient space in which the polynomial is Hurwitz (left half plane stable) polynomial. We obtain the necessary and sufficient condition of the structure of the transfer function of which the characteristic polynomial is a structural polynomial, In addition, this paper present another necessary and sufficient condition for the existence of a constant gain controller with which the characteristic polynomial is structurally stable, For the structurally stabilizable P controller, it is allowed that the transfer function may not to all pole plants.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.59-60
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• 2015

Wireless power transfer is a technique that supplies the necessary power to the various electronic devices over the air without wires. The technology is classified as near-field wireless power transfer technology using inductive coupling and far-field wireless power transfer technology using antenna. In this paper, RTLS tag for high-precision positioning and wireless power transfer module was designed in order to solve the power supply problem for facility management. was designed for high-precision positioning is possible RTLS tags and wireless charging. The wireless charging pad provides the capability to charge up to four devices using he magnetic resonance system.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.5
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• pp.349-355
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• 2019

A grid-connected inverter with critical loads should be able to supply a stable voltage to critical loads at mode change and during clearing time while detecting unintentional islanding. This study proposes a mode transfer method for a grid-connected inverter with critical loads. The proposed method, which integrates the grid-connected and islanded mode control loops into one control block, provides an autonomous and seamless mode transfer from the current control to the voltage control. Therefore, the proposed scheme can supply a stable voltage to critical loads at mode change and during clearing time. Experimental results are provided to validate the proposed method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06a
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• pp.57-64
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• 1998

The purpose of this research is to develop a CAD/CAM system for generation all kind of information such as, total drawing, sub assembly drawing, part drawing, detail drawing, part list, and NC data for machining by CNC lathe, Wire CUT, machining center. Through this study the CAD/CAM System for deep drawing transfer die in mechanical press process has been developed. The developed CAD system can generate the drawing of transfer die in mechanical press. Using these results from CAD system, it can generate the NC data to machine die's elements on the CAD system. This system can reduce design man-hours and human errors. In order to construct the system, it is used to automate the design process using knowledge base system. The developed system is based on the knowledge base system which is involved a lot of expert's technology in the practice field. Using AutoLISP language under the AutoCAD system, CTK customer language of SmartCAM is used as the overall CAD/CAM environment. Results of this system will be provide effective aids to the designer and manufacturer in this field.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.8
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• pp.1560-1566
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• 2015

To enable the efficient use of energy, the environment where unscheduled receivers can harvest energy from the transmitted signal is considered in next-generation wireless communication systems. In this paper, we propose a scheme for allocating subchannel and power to maximize the system throughput and harvested energy simultaneously using optimization techniques. Through simulations, we verify that the proposed scheme can increase the system throughput and harvested energy harmoniously. In particular, the proposed scheme improves the harvested energy remarkably with a negligible degradation of system throughput, compared with conventional scheme, as a result, energy can be used efficiently in the system.

• Journal of Power Electronics
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• v.11 no.4
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• pp.456-463
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• 2011

Grid-connected converters have widely adopted LCL filters to acquire high harmonic suppression. However, the LCL filter increases the system order so that the design of the system stability would be complicated. Recently, sole-loop control strategies have been used for grid-connected converters with L or LC filters. But if the sole-loop control is directly transplanted to grid-connected converters with LCL filters, the systems may be unstable. This paper presents a novel dual-loop power control strategy composed of a power outer loop and a current inner loop. The outer loop regulates the grid-connected power. The inner loop improves the system stability margin and suppresses the resonant peak caused by the LCL filter. To obtain the control variables, a single-phase current detection is proposed based on PQ theory. The system transfer function is derived in detail and the influence of control gains on the system stability is analyzed with the root locus. Simulation and experimental results demonstrate the feasibility of the proposed control.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.8
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• pp.649-654
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• 2002

The essential philosophy of the QFT(Quantitative Feedback Theory) is that a suitable controller can be found by loop shaping a nominal loop transfer function such that the frequency response of this function does not violate the QFT bounds. The loop shaping synthesis involves the identification of a structure and its specialization by means of the parameter optimization. This paper presents an optimization algorithm to estimate the controller parameters from the frequency transfer function synthesis using the TLS(Total Least Squares) in the QFT loop shaping procedure. The proposed method identifies the parameter vector of the robust controller from an overdetermined linear system developed from rearranging the two dimensional system matrices and output vectors obtained from the QFT bounds. The feasibility of the suggested algorithm is illustrated with an example.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1742-1747
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• 2015

An improved transfer alignment method for a strap-down inertial navigation system (SDINS) is presented here. The alignment accuracy in conventional method is vulnerable to the data latency of a Master INS (MINS) in high maneuverable platforms. We propose a time delay compensation equation considering higher-order terms in the attitude measurement equation of the Kalman filter. The equation incorporates additional information including angular rate, angular acceleration and linear acceleration from the MINS. Simulation results show that the transfer alignment accuracy is significantly improved in the high dynamic environment by incorporating the latency compensation technique.