• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.7.1-7.1
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• 2009

세계 어디에서나 에너지의 수요가 급속히 증가하고 있는 반면, 인류가 사용 가능한 에너지 자원은 그 한계가 보이고 있다. 더욱이지구 온난화 현상이 표면화되어 있는 현 시점에서 인류의 사회활동은 환경문제와 밀접하게 연관되어져서 생각해야 한다는 것이 지구라는 close system 에서는 명확하다. 한정된 에너지 자원을 유용하게 사용하여 인류 미래의 삶을 보다 윤택하게 유지하기 위하여서는 사용목적에 맞는 최적의 에너지 형태로 효율 좋게 변환하는 것은 무엇보다도 중요하다. 열전기술은 원래우주개발 및 군사관계에 우선적으로 사용된 기술로써, 냉전시대의 미국과 소련이 개발경쟁을 한 바 있다. 열을 전기로 바꾸는 열전발전과 전기를 열로 바꾸는 냉동 보온의 양면으로부터 우주 탐사기에 탑재된 발전기, 잠수함용 냉난방장치, 비상용 전원, 자동차용 전원 등 가지각색의 system 이 고안되었다. 냉전시대가 끝나고 우주 군사 관계의 기술이 외부로 확산되게 되었으나 열전분야에서는 변환효율이 크지 않다는 단점으로 인해 민생부분으로 즉각적으로 전이할 수없는 어려운 점이 내재해 있었다. 에너지 및 환경의 문제가 심각히 대두되고 있는 오늘날에 이르러서야재료 및 그 응용에 대한 연구가 다시 붐을 이루어 활발히 진행되고 있다. 본 발표에서는 열전소재의 효율을 높이기 위한 고차나노구조 제어기술 및 그것을 이용한 최근의 연구결과들을 소개한다.

• Journal of Advanced Navigation Technology
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• v.14 no.1
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• pp.49-56
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• 2010

Severe energy constraints and the low power consumption require the significance of the energy efficient error control mechanisms in wireless sensor network (WSN). In this paper, an automatic repeat request (ARQ) methodology for the analysis of error control schemes in WSN is presented such that the effects of packet length, the modulation scheme and the interference effect of the wireless channel are investigated. Moreover, an analyis of ARQ error control is provided by considering two major architectures for wireless sensor network, i.e., Mica2 and MicaZ sensor nodes. And the throughput performance of WSN with asynchronous FSK signal and DSSS-OQPSK signal with selective repeat ARQ scheme are analyzed in multiple interference environment, and the probability of receiving a correct bit and packet from target node to sink node is evaluated as a function of the channel parameter, the number of wireless sensor node, and the spreading factor.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.183-188
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• 2014

With the rapid growth of the mobile computing and sensor technologies, various application techniques related to USN converged with other related technologies are actively disseminated recently. Most of these applications are aimed at the proper control and system monitoring using context information gathered through various sensors. But it is not easy to control and monitor the system precisely and flexibly since data generated by sensors are huge and variety. In this paper, we design and implement the fuzzy-logic based central control system in USN to provide the flexibility and preciseness with sensed data. The performance of the proposed system is evaluated by a simulation study in terms of consumed electric power on the test bed of USN based streetlight control system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1153-1160
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• 2002

So far, the main applications of mobile client are querying data. However, we need a new mechanism to update data at a mobile client as mobile systems are advanced and extended. So, we present a optimistic concurrency control to schedule mobile transactions may include update operations.'rho read-only transactions can be terminated without sending information to a server, and update transactions are terminated by validating at a server. In our method, we can reduce the additional aborts by using a timestamp ordering and serialization graph test mechanism rather than using only conflict information between concurrent transactions.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.505-511
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• 1998

The silicide formation mechanisms of Co/Hf and Co/Nb bilayer on (100) Si have been investigated. We ob-served that crystallographic orientationso f the 500$^{\circ}C$ formed cobalt silcides were different each other with the varying intermediate layers. Epitaxial and non-epitaxial CoSi2 formed simultaneously in Co/Hf/(100Si. While only non-epitaxial CoSi2 formed in Co/Nb/(100) Si. The reason why the crystallographic orientation of CpSi2 is different for those two systems seemed to be relate to the formation and decomposition of stable reaction barriers at high temperature. The stable reaction barrier formed at high temperature could control the uniform diffusion of Co atoms which enables epitaxial growth of CoSi2.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.5
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• pp.1111-1116
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• 2005

The necessity of the home network have been enlarged gradually according to the distribution of ultra-high speed internet, the expansion of a digital information equipment and the change of a life pattern. In this paper, we proposed the embedded ethernet module that could be operate on eight bit system, but it could control home appliance with full ethernet speed. The embedded ethernet module consists of 8051 MCU and Hardware TCP/IP. In this module, we construct simple web server and port remote control program for I/O device control. We verified through internet that the developed embedded ethernet module could control and check home appliances anywhere and anytime. We expect the developed ethernet module can build up niche market at home network. And it will be helpful to activate home network market.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.189-194
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• 2002

It is thesis that based on for Croup-Transferring a method of Transferring-Control during real-time. By the development of multimedia, spread of high-speed communication network and generalization of various multimedia services, various techniques an studied by requiring application services for multi-users (meeting-service, remote-service, broadcasting-service, education-service and so on). So we focused on the multimedia group transferring techniques except communication network techniques and multimedia processing techniques, and presented algorithms about a mettled of group-management, a method of delay-control-management that analyzed a effective method of Croup-Control and characters of each group network and used RTP(Real-Time Protocol) / RTCP(Real-Time Control Protocol).

• Journal of Digital Convergence
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• v.13 no.1
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• pp.185-190
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• 2015

The trend of Internet of things are changed from public and examples of corporate center to B2C service. As you can see, through the practice of domestic and international services Internet of Things, conventional disaster, disasters, such as the case of the public sector, factory automation company now mainly direct B2C (Business to Consumer) services are affecting the individual has spread. In this paper we propose a method of platforms and components, and network configuration plan for exploration robot design based on remote control and monitoring system with IoT.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.196-199
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• 2005

Flow traveling over a cavity opening forms a vortex due to unstable shear layer and induces an aerodynamic pressure excitation from the diffusion of the vortex convecting out of the trailing edge of the opening. The interaction between the excitation force and the cavity response sustains resonance in the resonator(cavity) and locked-in vortex shedding at the leading edge of the opening. The aerodynamic excitation force can be described from the diffusion of the vortex over the trailing edge and the level of its diffusivity is related to the strength of vorticity seeded at the loading edge. In this study, the control scheme of the internal pressure oscillation was proposed from regulating the vorticity at the leading edge by use of an oscillating spoiler. It was found that the relative motion between the spoiler and the air mass at the cavity opening influenced vorticity strength and the control was achieved by direct feedback of the cavity pressure fluctuation to the actuator.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.105-107
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• 2009

Based on the rapid development of IT technology and deployment of the Internet through high speed networks, network environments have been changed from office oriented environment based on business industries and public institution even to the interconnection to digital electronics in the home network. Home network based applications are very diverse and the remote monitoring and control areas have been studied. In this paper, we present the design and implementation of a remote real time video monitoring system which provides the moving pictures on the web page through the Internet using JMF. In addition, we present the design and implementation of a remote light control system based on Zigbee.