• Korean Journal of Mathematics
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• 제5권2호
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• pp.185-193
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• 1997

In this paper, we study the $BP_*$-module structure of $BP_*$(BG) mod $(p,v_1,{\cdots})^2$ for non abelian groups of the order $p^3$. We know $grBP_*(BG)=BP_*{\otimes}H(H_*(BG);Q_1){\oplus}BP^*/(p,v_1){\otimes}ImQ_1$. The similar fact occurs for $BP_*$-homology $grBP_*(BG)=BP_*s^{-1}H(H_*(BG);Q_1){\oplus}BP_*/(p,v)s^{-1}H^{odd}(BG)$ by using the spectral sequence $E^{*,*}_2=Ext_{BP^*}(BP_*(BG),BP^*){\Rightarrow}BP^*(BG)$.

• 한국멀티미디어학회논문지
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• 제17권11호
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• pp.1279-1285
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• 2014

In this paper, we propose on image encryption method which uses NC(Non-linear Cycle) and 2D CAT(Two-Dimensional Cellular Automata Transform) in sequence to encrypt medical images. In terms of the methodology, we use NC to generate a pseudo noise sequence equal to the size of the original image. We then conduct an XOR operation of the generated sequence with the original image to conduct level 1 NC encryption. Then we set the proper Gateway Values to generate the 2D CAT basis functions. We multiply the generated basis functions by the altered NC encryption image to conduct the 2nd level 2D CAT encryption. Finally, we verify that the proposed method is efficient and extremely safe by conducting an analysis of the key spatial and sensitivity analysis of pixels.

• 산업경영시스템학회지
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• 제29권1호
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• pp.63-71
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• 2006

In this paper, we consider a planning problem arising from printed circuit board manufacturing industries. Given a set of several types of PCBs, component feeders and surface mounting machines in series in a PCB assembly line, the problem is to define the feeder allocation and job sequence with the objective of minimizing the total operation time of the line. We formulate the problem as a mathematical model. And, the problem is proven to be NP-hard, so a genetic algorithm is developed. Finally, we give test results to evaluate the performance of the genetic algorithm.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.195-196
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• 2006

Frame synchronization is an critical factor for an effective operation of OFDM (orthogonal frequency division multiplexing) based communication systems. In this paper, we present and analyze an efficient frame synchronization method based on m-sequence for OFDM-based mobile multimedia communication systems. The cyclic extension preceding OFDM frames is of decisive importance for this method. The m-sequence is added directly to cyclic extension signal in the time domain. By utilizing the autocorrelation characteristics of m-sequence, efficient frame synchronization can be achieved. And we also consider frequency offset estimation simultaneously. The proposed frame synchronization method can be applied to the OFDM-based mobile multimedia communication systems.

• Journal of Power Electronics
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• 제17권3호
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• pp.664-673
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• 2017

With the development of multilevel converters, cascaded single-phase H-bridge rectifiers (CHBRs) has become widely adopted in high-voltage high-power applications. In this study, sequence pulse modulation (SPM) is proposed for CHBRs. SPM is designed to balance the dc-link voltage and maintain the smooth changes of switch states. In contrast to phase disposition modulation, SPM balances the dc-link voltage even after removing the load of one submodule. The operation principle of SPM is deduced, and the unbalance degree of SPM is analyzed. All the proposed approaches are experimentally verified through a prototype of a four-module (nine-level) CHBR. Conclusions are drawn in accordance with the results of SPM and its imbalance degree analysis.

• Journal of Power Electronics
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• 제19권5호
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• pp.1315-1325
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• 2019

Aiming at the negative sequence and harmonic problems in the operation of railway static power conditioners, an optimization compensation strategy for negative sequence and harmonics is studied in this paper. First, the hybrid RPC topology and compensation principle are analyzed to obtain different compensation zone states and current capacities. Second, in order to optimize the RPC capacity configuration, the minimum RPC compensation capacity is calculated according to constraint conditions, and the optimal compensation coefficient and compensation angle are obtained. In addition, the voltage unbalance ${\varepsilon}_U$ and power factor requirements are satisfied. A PSO (Particle Swarm Optimization) algorithm is used to calculate the three indexes for minimum compensating energy. The proposed method can precisely calculate the optimal compensation capacity in real time. Finally, MATLAB simulations and an experimental platform verify the effectiveness and economics of the proposed algorithm.

• 한국정밀공학회지
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• 제14권5호
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• pp.76-84
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• 1997

A process sequence in precision press forming of electrnic components is investigated by the finite element method. Aperture, a key component of electronic gun, is formed through a sequence of about 15 operation, among which the beading & bending, the first piercing, the first coining, and the second coining operations are expected to be most critical in view of industrial experts opinions. Thus, the analysis per- formed by a commercial code MARC focuses on the three operations, and comparisons are made between the results of the analysis and the measurements of experimental forming of the component.

• Archives of Plastic Surgery
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• 제35권3호
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• pp.349-353
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• 2008

Purpose: There are 3 well-known surgical procedures to treat Pierre Robin sequence: tongue-lip adhesion, distraction osteogenesis of mandible, and tracheostomy. The classical tongue-lip adhesion is an effective way to keep airway. The tongue, however, becomes quite non-mobile and appears dormant until the patient could control upper airway and the adhesion can be maintained for prolonged period. Most of all, this procedure does not provide the correction of the micrognathia. Distraction osteogenesis is a good technique to correct micrognathia and to prevent tracheostomies in patients with Pierre Robin sequence. But airway keeping procedure is needed during the distraction period. The purpose of this study is to determine the usefulness of temporary tongue-lip traction during the initial period of mandibular distraction in Pierre Robin sequence patients with severe airway problems requiring operative procedure. Methods: It was a prospective study of 2 Pierre Robin sequence patients aged between 4 months and 6 months requiring surgical procedure to correct recurrent and severe pulmonary complications. Two patients underwent distraction osteogenesis of mandible. During the operation, deep one tension suture was performed to tract the tongue and lip. When the patient gained control of upper airway at the initial period of distraction and micrognathia was corrected, the traction suture was removed. Results: All patients were followed up. No patients complained severe pulmonary complications and tracheostomy could be avoided. No patients had severe pulmonary complication. The pulmonary condition of patients was good. Conclusion: In severe Pierre Robin sequence case, temporary tongue-lip traction is a good assistant method in distraction osteogenesis because this method can avoid tracheostomy.

• 한국정보전자통신기술학회논문지
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• 제8권6호
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• pp.470-477
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• 2015

본 논문은 통신 프로토콜의 적합성 시험시 하위 시험기와 상위 시험기간의 직접적인 상호 작용이 불가능한 분산 시험 환경에서 외부 동기화와 입출력 운용비용을 고려해야 할 경우 적용될 수 있는 최적화된 동기적 시험 항목 생성을 위한 새로운 방법을 제시한다. 이 방법은 세 가지 단계의 절차로 구성되어 있는데, 첫 번째 단계는 시험 구현물의 각 상태로부터 나오는 모든 입출력 짝들의 유일성을 기술하는 상태인식 표를 생성한다. 둘 째 단계에서는 이 상태인식 표로부터 각 상태의 동기화된 상태인식 열을 구성한다. 마지막 단계에서는 시험 구현물의 시험에지들과 각 상태의 동기화된 상태인식 열들을 이용하여 최적화된 동기적 시험열들을 생성한다. 본 논문의 방법은 원거리 시험기들을 사용하는 프로토콜 시험 구조에서 기 결정된 시험 항목을 적용할 때 시험 대상과 이들 시험기들간에 발생할 수 있는 동기화의 유용한 해결 기법으로 사용될 수 있다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2003년도 추계학술대회 및 정기총회
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• pp.85-88
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• 2003

In case that any jobs in a Job Shop can be scheduled on more than one machine and may have flexible operation sequences, with considering such case it is very difficult and complex to make the optimal process plans and scheduling. But they should be considered for an integrated model to perform more effective process planning and scheduling in this job shop problem. In this paper, we propose GA-based scheduling method to integrate effectively the problem of alternative machines, alternative operation sequences and scheduling. The performance of proposed GA is evaluated through comparing integrated scheduling with not integrated scheduling in molding company with alternative machines and operation sequences. Also, we use benchmark problems to evaluate performance. The scheduling method in this research will apply usefully to real world scheduling problems.