• 정보와 통신
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• 제26권2호
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• pp.23-30
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• 2009

3GPP(3rd Generation Partnership Project)는 3세대 이동통신인 UMTS(Universal Mobile Telecommunication System)의 초기 표준화 이후 HSPA(High Speed Packet Access), MBMS(Multimedia Broadcast/Multicast Service) 등의 기술 개발로 UMTS 시스템을 지속적으로 발전시켜 왔다. 그리고, 최근 새로운 무선 접속 기술에 기반한 LTE(Long Term Evolution)시스템에 대한 표준화를 거의 완료하고 ITU-R(International Telecommunications Union-Radio)의 IMT-Advanced 요구사항을 만족하는 LTE-Advanced 시스템에 대한 연구를 진행하고 있다. 한편 최근 다양한 무선 접속 기술간 핸드오버 기술이 중요한 이슈로 부각됨에 따라 LTE-Advanced에서도 이를 수용하기 위한 기술이 요구된다. 본 고에서는 3GPP에서 추진하고 있는 LTE-Advanced기술의 표준화 동향과 향후 이에 적용 가능한 다양한 무선 접속 기술간의 핸드오버 지원 기술을 살펴봄으로써 LTE-Advanced에서의 끊김없는 이동성(seamless mobility) 제공을 위한 근간을 제시하고자 한다.

• 농업과학연구
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• 제40권1호
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• pp.53-59
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• 2013

Analysis of load data during field operations is highly important for optimum design of power drive lines for agricultural tractor. Objective of the paper was to analyze field load data using FFT to determine frequency and the energy levels of meaningful cyclic patterns. Rotary tillage, plowing, baling, and wrapping operations were selected as major field operations of agricultural tractor. An agricultural tractor with power measurement system was used. The tractor was equipped with strain-gauge sensors to measure torque of four driving axles and a PTO axle, speed sensors to measure rotational speed of the driving axles and an engine shaft, pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to calculate power requirement. In rotary tillage, calculated frequency was decreased as travel speed increased. In baler operation, calculated frequency was increased as PTO speed was increased. The calculated peak frequency levels and expected levels were similar. Results of the study would provide information on power utilization patterns and on better design of power drive lines.

• 정보와 통신
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• 제28권8호
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• pp.10-17
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• 2011

3GPP($3^{rd}$ Generation Partnership project)는 3세대 이동통신인 UMTS(Universal Mobile Telecommunication System)의 초기 표준화 이후 HSPA(High Speed Packet Access), MBMS(Multimedia Broadcast Multicast Service) 등의 기술 개발로 UMTS시스템을 지속적으로 발전시켜 왔다. 그리고, 최근 새로운 무선 접속 기술을 기반한 LTE(Long Term Evolution)시스템에 대한 표준화를 완료하고 ITU-T(International Telecommnunications Union-Radio)의 IMT-Advanced 요구사항을 만족하는 LTE-Advanced 시스템에 대한 연구를 진행하고 있다. 한편 LTE-Advanced 표준의 목표인 무선 전송속도를 한층 더 높이고, 단위비용(cost per bit)을 더욱 낮추고, 셀 커버리지 및 용량을 확대하기 한 저출력의 피코셀, 펨토셀, 무선중계기들을 이용하여 실내외의 소규모 영역을 서비스하도록 하는 heterogeneous network에 대한 국제 표준이 활발히 논의되고 있다. 그러나 여러 셀이 혼재하는 경우 셀들간의 신호 간섭이 발생하여 사용자의 통신 품질이 크게 저하될 우려가 있다. 본 고에서는 heterogeneous network 와 관련하여 국제 표준 LTE-Advanced에서 논의되고 있는 간섭 제어 기법에 대해 소개한다.

• 자동차안전학회지
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• 제7권3호
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• pp.30-34
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• 2015

This study examined the Korean drivers' acceptance of SAS(Speed Assistance systems) and traffic sign conditions in Korea roads for SLIF(Speed Limit Information Function) that is a part of SAS. Exceeding the speed limit is a factor in the severity of many road accidents and SAS would help the driver to observe a speed limit by warning and/or effectively limiting the speed of the vehicle. SAS are in the initial phase in Korea, Korean drivers could not be familiar with automatical speed limiting during driving, SAS interface design would be considered to be more readily acceptable to the public. And advanced SAS have been introduced onto the market which are able to inform the driver of the current speed limit based on camera and/or digital maps based SLIF. These systems are based on external data using sensors, so environmental conditions are an important factor which could cause malfunction of SLIF functions.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.233-236
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• 2005

Our country compares with advanced nations by supply of super high speed network and information communication infra construction has gone well very. Many people by extension of on-line transaction and various internet services can exchange, or get information easily in this environment. But, virus or poisonous information used to Cyber terror such as hacking was included within such a lot of information and such poisonous information are threatening national security as well as individual's private life. There were always security and speed among a lot of items to consider networks equipment from these circumstance to now when develop and install in trade-off relation. In this paper, we present a high speed VPN Acceleration Board(VPN-AB) that balances both speed and security requirements of high speed network environment. Our VPN-AB supports two VPN protocols, IPsec and SSL. The protocols have a many cryptographic algorithms, DES, 3DES, AES, MD5, and SHA-1, etc.. The acceleration board process data packets into the system with In-line mode. So it is possible that VPN-AB processes inbound and outbound packets by 10Gbps. We use Nitrox-II CN2560 security processor VPN-AB is designed using that supports many hardware security modules and two SPI-4.2 interfaces to design VPN-AB.

• Journal of Advanced Marine Engineering and Technology
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• 제35권7호
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• pp.914-920
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• 2011

For a hydro turbine electricity generation system in river or bay, a venturi system could be applied to accelerate flow speed at the inlet of the turbine system in a flow field. In this study, a steady flow simulation was conducted to understand the effect of venturi system on the acceleration of current speed at the inlet of a hydro turbine system. According to the continuity equation, the flow speed is inversely proportional to the cross-section area in a conduit flow; however, it would be different in an open region because the venturi system would be an obstruction in the flow region. As the throat area is 1/5 of the inlet area of the venturi, the flow velocity is accelerated up to 2.1 times of the inlet velocity. It is understood that the venturi system placed in an open flow region gives resistance to the upcoming flow and disperses the flow energy around the venturi system. The result of the study should be very important information for an optimum design of a hydro turbine electricity generation system.

• 한국정보전자통신기술학회논문지
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• 제9권6호
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• pp.559-565
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• 2016

본 교차로에 각 방향별 이동류의 상충해소를 위한 목적으로 도입된 교통신호제어는 차량증가에 따라 여러 교차로를 연계하여 정지와 지체시간을 최소화하는 간선도로 제어 목적으로 바뀌었고 이를 위해 교통신호운영 효율화를 위한 다양한 방법이 제시되고 있다. 본 연구는 도심 가로축 연동체계를 교통운영체계 선진화 방안에서 제시하고 있는 비보호좌회전확대로 운영되는 선직진 후좌회전 체계와 기존 실시간 대응제어 신호운영체계를 비교 분석하였으며, 비교 분석을 위해 4개시 5개 지역을 선정 평균 교차로 간격, 연동 가로축 거리 등을 구분하였다. 그 결과 교통운영체계 선진화 방안 신호운영체계의 교통처리용량은 실시간 대응제어 신호운영체계의 교통처리용량 보다 주기 160초 때 차로 당 286대, 140초 경우 308대, 120초 경우 264대가 증가하여 1차로 도로확장을 한 만큼의 효과가 있는 것으로 나타났다. 또한 가로축 연동에 대해서도 가로축 길이 2.0~3.0km, 2.0km미만에서 분석 주기(160초, 140초, 120초) 모두에서 연동밴드 폭이나 정지횟수에서 효과가 있는 것으로 나타났다.

• Journal of Ubiquitous Convergence Technology
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• 제1권1호
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• pp.42-46
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• 2007

In this paper, we proposed an efficient short address allocation mechanism for WiBEEM devices using NAA(Next Address Available) algorithm. The proposed addressing mechanism is based upon the NAA information that is delivered over the beacons every time it is transmitted at the beginning of each super-frame. The NAA-based addressing mechanism is not a systematic way of allocating short addresses to newly joining devices and thus tree-routing cannot be supported. However, it has great advantages when U-City core services including U-Parking Lot System or ATIS(Advanced Traveler Information System) services that require high-speed mobility are considered. Moreover, the proposed addressing mechanism can provide significant expandability of the wireless network to various applications and fast device discovery.

• 전자공학회논문지S
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• 제34S권7호
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• pp.9-18
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• 1997

In this paper, we implemented the communication module in the Telephone Network Access Subsystem(TNAS) of the Advanced Communications Processing System(ACPS). We defined some kinds of communication tasks and related resources like several queues which are executed in real-time operating system, and implemented the procedures for processing the user information. Through traffic modeling and simulation, the performance of the Service Processing board Assembly(SPA) is evaluated in the aspets of system utilization and buffer size. The ACPS should accommodate various public networks such as public switch telephone network, packet switchen data network, frame realy netork, and ATM network. The communications module proposed in this paper could be used inthe interface beween the SPA and the High Speed Network Adaptor of other network interface subsystems.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.574-576
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• 2010

본 논문에서는 CCD 카메라를 이용해 리드프레임의 내부 리드부의 넓이와 선명도 및 결함 등을 고속으로 검사하는 시스템을 개발한다. 본 시스템은 조명부, 검사부, 조명 제어부, GUI 등으로 구성된다. 개발 기술로는 조명 제어, 고속 검사 알고리즘, 검사 분해능을 올리기 위한 계측기술 등이다. 현장 실험을 통해 개발된 시스템의 유효성을 검증한다.