• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.12
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• pp.2813-2819
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• 2015

In this paper, we investigate the physical layer network coding (PNC) technique in a two-way relay channel (TWRC) where two source nodes send and receive data with each other via a relay node. In particular, we consider the communication scenario where packet length from the two sources is different from each other. We analyze the bit error rate (BER) of the received packet at the relay node according to degree of overlapping between two packets. The BER of the short packet remains unchanged regardless of the degree of overlapping since the entire packet is overlapped with the longer packet, while the BER of the longer packet becomes improved as the degree of overlapping decreases. Thus, we need a novel transmission scheme to enhance BER performance of the PNC technique in TWRC environments since the overall BER performance of the PNC technique at the relay node depends on the worse BER between two ovelapping packets' BERs.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.5
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• pp.87-98
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• 2007

AAA protocol is an information protection technology which systematically provides authentication, authorization and accounting function not only in the existing wire network but also in the rapidly developing wireless network, various services and protocol. Nowadays, standardization of the various application services is in progress with the purpose of AAA standardization fer the mobile user in the wireless network. And various researches are being conducted fur using AAA in the roaming service and mobile IPv6 network between heterogeneous networks. In this paper uses OTP and ID-based ticket for user authentication in the mobile device under the ubiquitous environment, and service is seamlessly provided even though the mobile device moves from the home network to the foreign network. In addition, with the ticket renewed from the foreign network, the overhead of the home authentication server can be reduced, and provides anonymity of service through the anonymity ID.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.2
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• pp.239-248
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• 2012

VANET (Vehicular Ad-hoc Network) is a type of MANET (Mobile Ad-hoc Network) which is the next-generation networking technology to provide communication between vehicles or between vehicle and RSU (Road Side Unit) using wireless communication. In VANET system, a vehicle accident is likely to cause awful disaster. Therefore, in VANET environment, authentication techniques for the privacy protection and message are needed. In order to provide them privacy, authentication, and conditional, non-repudiation features of the group signature scheme using a variety of security technologies are being studied. In this paper, and withdrawal of group members to avoid frequent VANET environment is suitable for vehicles produced by the group administrator for a private signing key to solve the key escrow problem of a group signature scheme is proposed. We proposed a message batch verification scheme using Bloom Filter that can verify multiple messages efficiently even for multiple communications with many vehicles.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.4
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• pp.303-311
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• 2019

Reversible solid oxide fuel cell (RSOFC) has become a prospective device for energy storage and hydrogen production. Many studies have been conducted around the world focusing on system efficiency improvement and realization. The system should have not only high efficiency but also a certain level of simplicity for stable operation. External waste steam utilization was proved to remarkably increase the efficiency at solid oxide electrolysis system. In this study, RSOFC system coupled with waste steam was proposed and optimized in term of simplicity and efficiency. Ejector for fuel recirculation is selected due to its simple design and high stability. Three system configurations using ejector for fuel recirculation were investigated for performance of design condition. In parametric study, the system efficiencies at different current density were analyzed. The system configurations were simulated using validated lumped model in EBSILON(R) program. The system components, balance of plants, were designed to work in both electrolysis and fuel cell modes, and their off-design characteristics were taken into account. The base case calculation shows that, the system with suction pump results in slightly lower efficiency but stack can be operated more stable with same inlet pressure of fuel and air electrode.

• Journal of the Korean Geotechnical Society
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• v.26 no.7
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• pp.107-115
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• 2010

In this paper, the applicability of cement grout bas been studied as an alternative to bentontite grout to backfill ground heat exchangers. To provide an optimal mixture design, the groutabilty and thermal conductivity of cement grouts with various mixture ratios were experimentally evaluated and compared. The unconfined compression strength of cement grout specimen was measured, which was exposed to cyclic temperature variation ranging from $50^{\circ}C$ to $-5^{\circ}C$. In addition, the integrity of the interface between circulating HDPE pipes and cement grout was evaluated by performing equivalent hydraulic conductivity tests, on the specimen. in which a pipe locates at the center of the specimen.

• Restorative Dentistry and Endodontics
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• v.36 no.6
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• pp.510-514
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• 2011

Mineral trioxide aggregate (MTA), which was originally developed for repair of root perforations, is a biocompatible material with numerous clinical applications in endodontics. MTA must be allowed to set in the presence of moisture to optimize the material's physical and chemical properties. In the clinic, occasionally unset MTA has been detected after application of MTA on the tooth, and the reason has been unclear. This case report presents MTA washed-out for several years after placement at the root apex as an apical plug, and discusses the reason and things to consider in clinics.

• The Korean Journal of Zoology
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• v.30 no.3
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• pp.311-323
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• 1987

생쥐의 섬 유아세포(MEP)와 종양세포(SCK)를 이용하여 정상세포와 종양세포 사이에 열 감수성의 차이가 있는지의 여부 및 환경의 pH가 이 세포들의 열감수성과 heat shock protein(HSP) 합성에 미치는 영향을 생존곡선과 HSP합성 kinetics등을 써서 검토하였다. MEF와 SCK 세포를 정상 pH(7.4) 또는 산성 pH(6.7)에서 42"C에서 2시간 온열처리 후 3일간에 걸쳐 생존을을 비교해 븐 결과, ME선와 SCK세포 사이에 생득적 열강수성의 차이는 없었고 산성 P광에서는 세포의 종류에 관계없이 열감수성 이 증감되었다. 온열처리의 결과 유도되는 내일성이 conditioning Leat의 크기와 어떤 관계가 있는지를 보기 위해서 45"C에서 5분 또는 20분을 주어본 결과 체은 conditioning heat를 주었을 때 내일성이 신속히 그리고 높은 수준으로 발생하였고, 이러한 열 감수성의 kinetics는 HSP의 합성 kinetics와 잘 일치하였다. 단백질, 특히 HSP 합성에 미치는 PH의 영 향을 알아보기 위해서 46"C에서 6분간의 heat shock를 주어 본 바 전반적인 단백질 및 major HSP의 합성양상에는 별로 차이를 보이지 않았다. 그러나 SCK 세포에 43"C에서 30분의 온열처리를 주고 새로 합성되는 HSPSP의 kinetics를 검토해 본 결과 정상 P반에서는 0-5시간에 합성이 일어나나 산성 PH에서는 3-9시간에 합성이 일어나서 몇시간의 합성지연이 관찰되었다. 아울러 HSP68, HSPTC, HSP87을 Peptidemapping하여 본 결과 HSP68과 HSP70 은 유사한 peptide fragment pattern을 보여 amino acid sequence는 유사하고 기능도 같을 것으로 추론되었으나 HSP87은 전혀 다른 pattern을 보였다. 전혀 다른 pattern을 보였다.

• The KIPS Transactions:PartA
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• v.19A no.1
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• pp.61-68
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• 2012

Since the increasing use of smart devices such as smartphone and tablet PC improves the quality of convergence of broadcasting and telecommunication, many new media have been created. This smart device can provide personal environments based on user's profile (age, gender, and job) and current location. In addition, it can be regarded as a media platform with two-way communication. This paper proposes personalized message syndication, called PMS, based on smart devices and then analyzes its business and technical issues. The PMS service as a smart media provides consumers customized information and can be used for producer's marketing tools which can lead consumers' heart and participation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.6
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• pp.556-561
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• 2009

The UAV(Unmanned Aerial Vehicle) that is remotely operating in various and long flight environments must have a very reliable propulsion system. Precise fault diagnosis of the turbo shaft engine for the Smart UAV that has the vertical take-off, landing and forward flight behaviors can promote reliability and availability. This work proposes a new diagnostic method that can identify the faulted components from engine measuring parameter changes using Fuzzy Logic and quantify its faults from the identified fault pattern using Neural Network Algorithms. The proposed diagnostic method can detect not only single fault but also multiple faults.

• KSBB Journal
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• v.10 no.1
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• pp.46-54
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• 1995

The physiological characteristics of carrot hairy roots and suspension cells were examined based on their nutritional requirements. Inorganic nutrient (phosphorous and ammonium) requirements of carrot hairy roots were similar to those of suspension cells. Optimal sucrose concentration for the growth of hairy roods (7%) was different from that of suspension cells (3%). Since suspension cells were move easily affected by the environmental condition, e.g., osmotic stress, than hairy roofs which made the suitable growth condition for cells, it can be understood that optimal sucrose concentration for the growth of hairy roots was higher than that for the growth of the suspension cells. To investigate the roles of sucrose on the growth of hairy roots, the effects of sucrose on the fresh weight and dry weight was analysed by the addition of mannitol as an osmolicum. Sucrose acts also as an energy source for hairy roots rather than as an osmotic regulator, since the increase of dry weight was higher than that of fresh weight at the given sucrose concentration.