• 한국멀티미디어학회논문지
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• 제23권2호
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• pp.227-240
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• 2020

This paper proposes a novel CTC technology, CB-sense. The CB-sense guarantees a dedicated period for the CTC that results in low duty cycle of the receiver device. In addition, it send a lot of information explosively during the dedicated CTC period. Thus, it can achieve high throughput. The CB-sense uses Clear to Send (CTS) packets to transmit information bits to the heterogeneous wireless technologies. The CTS packets block the neighboring node transmissions, so it reduces co-channel interference. In experiment results, CB-sense represents 20 times more throughput than FreeBee and below 5% symbol error rate in the interference environment.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2021-2026
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• 2008

Recently, a high speed rail consists of many train coaches and power cars. For keeping the reliable train communication system with train coaches and power cars, train uses the OSI model(Open Systems Interconnection Basic Reference Model) and KTX(Korea Train eXpress) only uses the Physical to Transport layer of OSI model. This paper describes the analysis of CLNP(Connectionless Network Protocol) and ES-IS(End System to Intermediate System) protocols used in KTX for the network layer. CLNP is used to send data to other system and ES-IS protocol is used to route and send information between end systems and intermediate systems. Also this paper presents the protocol parsing program and implementation of Network layer.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2004년도 추계학술대회 및 정기총회
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• pp.395-398
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• 2004

It is effective and desirable for a proper customer relational management(CRM) to send an email of product sales' advertisement bills for the prospective customers rather than to send spam mails for non specific customers. This study identifies the prospective customers with high probability to buy the specific products using Artificial Neural Network(ANN) and Induction Rule(IR) technique. We suggest an integrated model, IRANN of ANN and IR of decision tree program C5.0 and, also compare and analyze the accuracy of ANN, IR, and IRANN each other.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2003년도 가을 학술발표논문집 Vol.30 No.2 (3)
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• pp.76-78
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• 2003

기존 유선 인터넷과 달리 무선 인터넷은 낮은 대역폭. 빈번하게 접속이 끊기는 현상, 단말기내의 낮은 컴퓨팅 파워 및 작은 화면, 사용자의 이동성 등의 특성에 따른 많은 제약점들을 갖고 있다. 또한 무선 인터넷 서버는 급증하는 사용자에 따른 대용량 트래픽을 처리할 수 있도록 확장성이 있어야 한다. 이에 위의 문제를 캐싱(Caching)과 압축(Transcoding, Distillation)으로 해결하는 방법으로 무선 프록시 서버를 사용한다. TranSend는 클러스터링 기반의 무선 프록시 서버로 제안된 것이나 시스템적인(Systematic) 방법으로 확장성을 보장하지 못하는 단점을 가진다. 이에 본 논문에서는 시스템적인 방법으로 확장성을 보장하는 클러스터링 기반의 무선 인터넷 프록시 서버를 제안한다. 16대의 컴퓨터를 사용하여 실험을 수행하였고 실험 결과 TranSend 시스템에 비해 32.17%의 성능 향상을 보였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.967-968
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• 2006

This paper proposes a novel system to send images in a narrow band network and to measure water level. In order to send images in narrow band network, we use JPEG compression technique based on the difference image. The difference image is obtained by subtracting the current image from the predefined reference image. The water level is measured to make use of the camera calibration and the edge information of the received image.

• Journal of Ubiquitous Convergence Technology
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• 제1권1호
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• pp.28-34
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• 2007

Tree-based reliable multicast protocols provide scalability by distributing error-recovery tasks among several repair nodes. These repair nodes perform local error recovery for their receiver nodes using the data stored in their buffers. We propose a packet loss patterns adaptive feedback scheduling scheme to manage these buffers in an efficient manner. Under our scheme, receiver nodes send NAKs to repair nodes to request packet retransmissions only when the packet losses are independent events from other nodes. At dynamic and infrequent intervals, they also send ACKs to indicate which packets can be safely discarded from the repair node's buffer. Our scheme reduces delay in error recovery because the requested packets are almost always available in the repair node's buffers. It also reduces the repair node's workload because (a) each receiver node sends infrequent ACKs with non-fixed intervals and (b) their sending times are fairly distributed among all the receiver nodes.

• Journal of Electrical Engineering and information Science
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• 제2권6호
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• pp.162-166
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• 1997

A message server have two basic functionalities, a server role for processing the processing the user environment as well as an entity role for transferring message to other entity in message system environment. The user who is going to send and receive his important information really wants to keep his own security requests. To satisfy this requirement, message server must be enforced by two seperated security policies- one for message processing security policy under department's computer working environment, the other for send/receive security policy under message system's communication path environment. Proposed access control model gurantees the user's security request by combining constrained server access control and message system access control with multi upper bound properties which come from inheritance attributes of originating user security contexts.

• 반도체디스플레이기술학회지
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• 제11권3호
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• pp.51-56
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• 2012

In this paper, we propose a telemedicine system based ECG data using a bio-signal meter and a smart device for treating faraway patients. This system is composed of a patch-shaped portable bio-signal meter, patient's smart device application, and doctor's PC software. Using these components, doctors and patients can do telemedicine. First, a patient measures his own ECG signal with a bio-signal meter and send the data to a doctor using a smart device application. Then, the doctor checks the ECG data, and make and send a diagnosis chart to web server. Likewise, doctors and patients can be offered a medical environment without time and space restraints. Applying this system to real medical system can improve the problem of low accessibility and efficiency and also can reduce medical expenses.

• Journal of Communications and Networks
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• 제14권1호
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• pp.63-74
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• 2012

Multicast data communication is an efficient communication scheme, especially inmulti-hop ad hoc networks where the media access control (MAC) layer is based on one-hop broadcast from one source to multiple receivers. Compared to unicast, multicast over a wireless channel should be able to deal with varying channel conditions of multiple users and user mobility to provide good quality to all users. IEEE 802.11 does not support reliable multicast owing to its inability to exchange request-to-send/clear-to-send and acknowledgement packets with multiple recipients. Thus, several MAC layer protocols have been proposed to provide reliable multicast. However, additional overhead is introduced, as a result, which degrades the system performance. In this paper, we propose an efficient wireless multicast MAC protocol with small control overhead required for reliable multicast in multi-hop wireless ad hoc networks. We present analytical formulations of the system throughput and delay associated with the overhead.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.82-85
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• 2005

이동 Pv6(MIPv6)를 지원하는 네트워크에서 이동 노드(mobile node)가 새로운 네트워크로 이동했을 때 그 네트워크에서의 엑세스 라우터와 엑세스 포인트(Access Router/Access Point)를 찾아 연결해야 한다. 이때 신뢰할 수 있는 AR과 AP에 연결하지 못할 경우 여러 형태의 공격에 노출된다. 본 논문에서는 SEcure Neighbor Discovery(SEND)에서 사용하는 공개키 기반 RSA 암호화 방식을 응용하여 AR/AP와 MN이 상호 인증할 수 있는 방안을 제시한다.