• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.98-105
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• 1993

본 논문에서는 설계 경험이 적은 설계자가 효율적으로 선급규정을 이용하여 선체설계를 할 수 있도록, 범용 전문가시스템 쉘(Shell)인 NEXPERT를 이용하여, 선체 구조설계를 지원할 수 있는 전문가시스템을 개발하였다. 먼저, 선급규정집(LLoyd Rule)과 기존의 rule scantling프로그램으로부터 지식을 추출하고, 이를 바탕으로 객체지향개념에 의해 지식의 그룹핑과 계층화를 시도하였다. 또한, NEXPERT가 갖고 있는 외부 프로그램과의 접속기능 (Cellable Interface)을 이용하여 각종 설계에 필요한 프로그램과 실적선 데이타베이스를 접속하였다. 특히, Motif를 이용한 그래픽 사용자 인터페이스(Graphical User Interface:GUI)를 도입하였고, 설계자가 결과에 대해 검토를 할 수 있도록 Knowledge tracing기능을 부여함으로써, 사용자 지향의 구조부재 치수 결정 지원 전문가 시스템을 개발하였다. 이러한 연구를 통해 범용 전문가시스템이 선박설계에 이용될 수 있다는 가능성을 보였으며, 그 추구해야할 방향을 설정하였다. 특히, 어떤 설계결정에 이르는데 관여한 규칙들을 보여주며, 객체로 정의된 설계부재들의 값을 확인하게 함으로써 설계자가 효율적인 설계를 수행할 수 있게 되었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.5
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• pp.1282-1290
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• 1998

In this paper, the physical layer design of IMT-2000 system being developed by SK Telecom is introuduced. The outband signaling scheme and the two-pilot scheme are adopted for multimedia service and inter-cell asynchronous mode respectively. In addition, the synchronous transmission scheme is proposed to reduce the interference in the reverse link. The algorithm and simulation results of 'two-pilot scheme' for inter-cell asynchronous mode and 'reverse synchronous control' for synchronous transmission are presented.

• Review of KIISC
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• v.28 no.3
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• pp.38-46
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• 2018

블록체인 기술은 분산형 네트워크를 통해 정보 등을 관리하고 저장함으로써 정보의 투명성 및 신뢰성을 제공해줄 수 있는 분산 컴퓨팅 기반의 데이터 위변조 방지 기술이다. 특히 수천만개 사물 기기들이 서로 통신을 하여 서비스를 제공하는 사물인터넷(IoT) 서비스 환경에서 블록체인 기술은 중앙 집중 방식의 관리 구조를 탈피하고 보안성을 향상시킬 수 있는 인프라 기술로 주목 받고 있다. IoT 서비스에 데이터 무결성 및 디바이스 제어 등의 보안서비스를 제공하고, 분산화된 방식으로 서비스의 확장성을 높이고자 최근 글로벌 기업들은 IoT 블록체인 개발을 위한 컨소시엄을 구성하여, IoT 서비스에 활용할 수 있는 블록체인 기반 기술들을 연구하고 있다. 본 논문에서는 블록체인을 기반으로 한 IoT 연구 프로젝트들의 연구기술 동향을 분석하고, IoT 서비스에 블록체인을 적용한 사례와 응용 기술 등을 소개한다. 또한 IoT 응용 서비스에 효과적으로 적용하기 위해 기존 블록체인 기법들의 확장성 및 오버헤드 등의 문제를 개선한 Tangle 기술에 대해서 자세히 소개하고, IoT에 블록체인을 적용하기 위한 고려사항들을 논의한다.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.228-231
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• 2000

When the vector control which does not need a speed signal from a mechanical speed sensor it is possible to reduce the cost of the control equipment and to improve the control performance in many industrial application. In this paper describes a rotor speed estimate method of induction motor based on the theory of counter EMF MRAS. This method eliminated the pure integrator. and we can be expected to rapid responsibility of the speed identification, Therefore we improve the initial condition of the integrator and drift problem. The stability of speed estimator is proved on the basis of hyperstability theory. In order to confirm the performance of the proposed system Simulation and experiment is performed.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.957_958
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• 2009

2DOF is applied to induction moor in order to supply these weak points of PI speed control method in this paper. and proposed method utilize the combination of the voltage model based on stator equivalent model and the current model based on rotor equivalent model, which enables stable estimation of rotor flux. And it also emphasizes the improvement of the control characteristics in low speed region where established schemes have many problems. To prove the propriety of this paper, the various simulations carried out adequacy and stability using Matlab, and at the same time real system is made, so it is proved. As the results of embodying the system, the robust system is realized.

• Archives of Plastic Surgery
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• v.33 no.5
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• pp.577-580
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• 2006

Purpose: Hemangioma of the breast is an infrequent finding and usually encountered incidentally when checking for other disease. Most of hemangiomas of the breast are asymptomatic, not palpable perilobular type. Cavernous hemangioma of the breast is rare and only a few reports about this type of lesion are present. No example has been reported about reconstruction of the breast after resection of large cavernous hemangioma. Methods: We report here a case of immediate breast reconstruction using a Becker implant after subcutaneous mastectomy for a large cavernous hemangioma involving almost entire breast. Results: Symmetry is well maintained after 3 years without deformity or recurrence. Conclusion: The clinical prognosis of breast cavernous hemangioma is good after total excision and reconstruction.

• Microbiology and Biotechnology Letters
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• v.27 no.6
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• pp.484-490
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• 1999

Various materials including sodium alginate, k-carrageenan, collagen and polyacrylamide were studied in order to maintain the stability of bioluminescence of Photobacterium for the monitoring of volatile toxic substances. Kinetic parameters of specific rate($\mu$), and gamma(${\gamma}$) value were determined for the relationship between bioluminescence of immobilized P. phosphoreum and toxic substances. The bioluminescence intensity was found to be proportional to the concentration of toxic substances and the free cells were shown to be more sensitive than immobilized cells when volatile substances were exposed to the cells. Bioluminescence increased slightly after several minutes, which was due to the volatility of toxic compounds. Furthermore, P. phosphoreum immobilized on strontium alginate was better than cells immobilized on sodium alginate for the response to substances used.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.649-651
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• 2003

이동성을 가진 다수의 노드들에 의해 자율적으로 구성되는 이동 임시무선망(Mobile Ad Hoc Network)은 홈 네트워크, 센서 네트워크, 개인망 등 다양한 응용 분야로의 적용이 활발히 이루어지고 있지만 무선망이라는 속성 때문에 보안에 취약한 문제점을 안고 있다. 본 논문에서는 이동 임시 무선망에서 이동 노드들간에 보안성을 강화하기 위해 키들을 관리하는 기법을 제안한다. 임시 무선망에서 키를 분배하는 기법 중 완전 분배형 인증 기법이 널리 적용되고 있으며 임의의 노드를 기준으로 주변에 특정 개수 이하의 노드가 활동 중인 경우에도 키 관리를 원활히 할 수 있는 기법을 제안한다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.14 no.3
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• pp.2716-2725
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• 1972

Side channel spillways based on Hinds theory were tested. Surface water level at the beginning point of side channel is the same as the crest level of weir in the usual design. Here, side channel section were moved upwards $\frac{1}{2}$ of the total head on the crest and test(revised experiment) were made. In the revised experiments, coefficients of discharge for design flood (Q) were the same with that of original design experiments. In case of 1.2Q a little influence of submergence were appeared, coefficients of discharge were decreased to be about 97.6% of that of original design experiments, therefore, Reservoir flood water level become higher about 2-3cm than original case. So revised design can be used for actual purpose and it will brings much savings in construction cost of side channel spillway.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.4
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• pp.575-579
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• 2006

In this paper, an instantaneous speed observer with a reduced order is proposed to implement an indirect control for a motor with excellent dynamic stability and performance in a very low speed region. The proposed observer can estimate the instantaneous speed in very low speed region and simplify the system configuration by adopting an least order load torque-inertia observer to estimate the load torque and the motor speed. Simulation are carried out to illustrate the performance of the proposed estimator at very low speed.