• Journal of Internet Computing and Services
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• v.7 no.4
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• pp.79-90
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• 2006

Data broadcasting is an efficient method for disseminating data, and is widely accepted in the database applications of mobile computing environments because of its asymmetric communication bandwidth between a server and mobile clients. This requires new types of concurrency control mechanism to support mobile transactions executed in the mobile clients, which have low-bandwidths toward the server. In this paper, we propose an OCC/DTA (Optimistic Concurrency Control with Dynamic Time-stamp Adjustment) protocol that can be efficiently adapted to mobile computing environments. The protocol reduces communication overhead by using client-side validation procedure and enhances transaction throughput by adjusting serialization order without violating transaction semantics. We show that the proposed protocol satisfies data consistency requirements, and simulate that this protocol can improve the performance of mobile transactions in data broadcasting environments.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.2
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• pp.94-100
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• 2005

Korea Electrotechnology Research Institute(KERI) has successfully developed a 100hp-1800rpm-class high temperature superconducting(HTS) motor with high efficiency under partnership with Doosan Heavy Industries & Construction Co. Ltd. This motor has a HTS field winding and an air-cooled stator. The advantages of HTS motor can be represented by a reduction of 50% in both losses and size compared to conventional motors of the same rating. The cooling system is based on the heat transfer mechanism of the thermosyphon by using GM cryocooler as cooling source. The cold head is in contact with the condenser of a Ne-filled thermosyphon. Independently, the rotor assembly was tested at the stationary state and combined with stator. The HTS field winding could be cooled into below 30K. Test of open-circuit characteristics(OCC) and short-circuit characteristics(SCC) and load test with resistive load bank were conducted in generator mode. Also, load tests in motor mode driven by inverter were finished at KERI. Maximum operating current of field winding at 30K was 120A. From OCC and SCC test results synchronous inductance and synchronous reactance were 2.4mH, 0.49pu, respectively. Efficiency of this HTS machine was 93.3% in full load(100hp) test. This paper will present design, construction. and experimental test results of the 100hp HTS machine.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06c
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• pp.395-398
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• 2007

본 논문에서는 사람이 생각하고 표현하는데 영향을 주는 감성 요인을 사용하여 컴퓨터가 다양한 환경에 적응하며 지능을 표현할 수 있는 에이전트 모델을 제안한다. 감성은 사람이 생각하고 판단하는데 중요한 요소가 되고, 이러한 감성을 에이전트에 표현하면 사람의 추론하는 과정을 효과적으로 표현할 수 있다. 이에 사람의 추론 과정을 표현하기에 적합한 한 에이전트 모델인 BDI(Belief, Desire, Intention) 에이전트 모델을 감성과 결합하여 에이전트들의 행동을 빠르게 결정할 수 있는 ExMEBDI(Expanded Multi Emotional BDI) 에이전트 모델을 제안한다. 또 기존의 사람의 감성을 모델로 구성된 OCC모델을 기반으로 ExMEBDI 모델의 감성 추출 방법인 GEM(Generated EMotion)을 제안하였다.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.3
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• pp.67-73
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• 2004

Effect of calendering on structural and surface properties of sheets made of various pulp was investigated. BKP, BCTMP and KOCC were used as raw materials for handsheets and sheets were calendered at the different calendering temperature and pressure conditions. Caliper, air permeability, and PPS roughness were reduced by calendering, but their effects were a little different depending on pulp type and calendering condition. Increase of density with increase of calendering Pressure was remarkable on sheet made of BCTMP or KOCC, and the effect of temperature was more significant than pressure. PPS roughness of sheet made of BCTMP or KOCC was reduced by calendering, but BKP sheet showed little reduction of roughness at higher calendering pressure. The compressibility of sheet increased logarithmetically with calendering pressure and surface compressibility of KOCC sheet was relatively higher than other pulps.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.217-226
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• 2011

• Information and Communications Magazine
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• v.33 no.10
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• pp.10-16
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• 2016

IEEE 802.15.7 VLC(Visible Light Communication) 규격 이후에 카메라 기반 ISC(Image Sensor Communication) 관련 개정 필요성이 제기되어서 현재 IEEE 802.15.7m OWC(Optical Wireless Communication) TG가 표준화를 진행 중에 있다. 2016년 5월에 결정된 Baseline Document D0를 기반으로 LiFi(Light Fidelity), OCC(Optical Camera Communication) 및 LED-ID(LED Identification) 기술로 간단하게 분류하고 각 핵심 변조 기법을 소개한다. 5세대 이동통신과 함께 사용될 수 있는 다양한 IoT/ M2M 응용 서비스(LED, 디지털사이니지, 방송, 자동차 안전, 디스플레이 등)들이 포함되어 있다. 국내에서 혁신적인 비즈니스 모델 발굴과 국내 산/학/연/관이 협력하여 가시광, 적외선 및 자외선 분야에서 적극적인 연구개발이 있어야 할 것이다.

• Journal of Internet Computing and Services
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• v.3 no.6
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• pp.79-89
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• 2002

The performance of OCC is very sensitive to the transaction abort rate, Even if the abort probability can be reduced by re-ordering, most of re-ordering schemes have space overhead in maintaining a graph or histories, In this paper, we proposed an efficient re-ordering scheme based on a broadcast invalidation mechanism. Our scheme, called CBI, can reduce the abort probability without space overhead in maintaining a graph or histories, By simulation studies, we showed that CBI reduced the abort rate and unnecessary operations, Additionally, we showed that CBI outperforms not only BTS but also TSH with low space overhead.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.4 s.112
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• pp.8-17
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• 2005

WCT (Wet compaction test) is a new fiber evaluation method developed recently by Seo and its test results can be used as a predictor for pulp quality and its paper property Bleached chemical pulps (SwBKP, HwBKP), recycled pulp (OCC), and mechanical pulp (BCTMP) were used for the furnishes to be tested by WCT We compared the WCT results to conventional fiber evaluation tests such as WRV (Water Retention Value), free ness, and fiber length in this study, and found that WCT always gave better regression coefficients in relation to pulp quality (drainage), and paper properties (density, tensile, tear, and burst strength). WCT may be used on-line in papermachine.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04b
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• pp.227-231
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• 1999

Condebelt drying provides opportunities not only of improving the strength properties and saving of drying energy but also of reducing the basis weight or increasing the utilization of recycled furnishes. In this paper general overview of the Condebelt press drying will be described and the effects of the process variables in Condebelt press drying including drying temperature, pressure, drying time and moisture content of the sheets on the paper properties is discussed. The experiment was performed with a static rig and Korean OCC was used as a principal raw material. Significant improvement in sheet density, compression strength, tensile strength, surface smoothness, etc. was obtained when Condebelt drying was applied. Control of pressure and inlet dryness was found to be very critical in improving sheet properties. Mill experiences from Dong Il Paper Mfg. Co., Ltd is briefly described.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06c
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• pp.340-343
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• 2008

유비쿼터스 컴퓨팅 환경에서 서비스는 환경 정보를 감지하고 그 정보를 바탕으로 대상 사용자에게 서비스를 제공해준다. 이때, 수행되는 서비스는 사용자로부터 명시적인 요청을 받아 수행되는 것이 아니라, 주어진 상황을 기반으로 자동으로 수행되는 것이기 때문에, 이 서비스가 사용자가 정말 원하는 서비스인가를 판단하는 것은 서비스를 수행하는 시스템에 대한 신뢰도 평가에 중요한 기준이 된다. 이에 본 논문에서는 사용자의 의도에 맞는 서비스 수행을 보장하기 위해, 서비스에 대한 사용자의 만족도를 평가하는 방법을 제안한다. 제안된 방법은 OCC 감정 모델을 기반으로 사용자의 서비스 만족도를 계산하고, 이 결과를 통해 사용자의 의도와 서비스의 수행 조건을 일치시킨다. 만족도 계산 작업의 자동화를 통해 서비스의 수행 조건은 사용자의 의도 변화에 따라 동적으로 변경 가능하고, 이를 통해 사용자는 시스템에 대한 하위수준의 조정 작업 없이 자신의 행동 변화만으로 서비스의 실행 조건을 변경시킬 수 있다.