• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.123-131
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• 2004

Internet is absolutely contributed to information technology revolution nowadays. Internet services such as voice and data, etc. are provided home or small office via home gateway. The development of communication equipment via home gateway is implemented rapidly, and its product various. This paper presents the design and implementation of the VoIP equipment including the telephone function based on the embedded environment and being connected to the home gateway and the PC because of taking 2-ethernet LAN ports. As developing environment, the STLC1502 developed at ST Microelectronics as single chip solution, VxWorks as RTOS, and C language as coding mechanism are used. The verification of the developed systems for the voice test is carried out for the gatekeeper via Internet. The performance parameter is considered as the call processing capacity measuring the time of the call setup and clearing, and the data processing capacity for the file transfer. As a call setup and clearing is about 95ms, the call processing capacity is about 10 calls per second. The data processing capacity is 5.7Mbps in case of file transfer of server and client environment. Therefore the performance result is satisfied in the aspect of the call processing time and the data transfer time in Internet.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.659-662
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• 2012

In this paper, the service system the urgent of the danger area or the managed object region is proposed whether the system is autonomously the police or situation where it informs through the police car and it can convey the contextual information or not. In case the nodes location is continuously confirmed from the gateway and it queues and the event is generated in the server of system whether it is the situation, or not the system to be proposed transmits the event triggered message and system transmitting the video message to the nearby which the event is generated node. As a result of the test, in case the event was generated in the server whether it was the situation, or not it confirmed to transmit the video message as the route where it is stored in the server.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.5
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• pp.231-238
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• 2017

A Class B device in LoRaWAN periodically receives a Beacon message from a gateway for synchronization, and it also periodically activates a ping slot to receive data from the server. In this paper, we save energy consumption by controlling the beacon-less operation which is immediately started on the packet loss. In addition, we propose a method that the server inactivates the ping slots of a device according to the amount of messages, which have to be received from the server, to save energy consumption resulting from activated but unused empty slots. The experiment with the 20% of packet loss rate showed that the reduced beacon-less operation and the inactivation of the ping slot decrease the energy consumption by 96.7% and 60% as compared to the existing method.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.403-405
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• 2004

본 연구는 미들웨어 기반의 OSGi(Open Service Gateway initiative) 서비스 플랫폼과 규칙 기반 생성 시스템 기술을 응용하여 유연하고 효율적인 홈 서버 아키텍처를 제안한다. 미들웨어 컴포넌트인 서비스를 엔진은 서비스로부터 요청된 호출을 정해진 규칙에 따라 평가 판단하여 홈 기기들을 제어하고 관리한다. 서비스 룰 엔진은 실행 규칙이 명세 되어 있는 프로파일을 참조하여 처리하고, 홈 기기 접근 권한과 현재 서로 상충되는 홈 기기가 작동 중인지 점검하며, 우선순위와 충돌 방지 조건 및 제약조건을 조회하여 홈 기기를 제어한다. 이때 방제, 보안에 관련된 홈 기기의 작동이 요구되는 경우 정해진 방재, 보안 규칙에 따라 가장 먼저 수행된다. 프로파일은 사용자가 서비스를 매니저를 통해 관리하거나 외부의 접근 허가된 사용자가 관리할 수 있으며, 여러 형태의 프로파일이 제공되어 사용자의 성향에 따라 프로파일을 선택하여 홈 서버에 적용할 수 있다

• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.238-240
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• 2006

현재 RFID 네트워크의 구조적 기준이 되는 EPC 네트워크는 HTTP/SOAP 통신 프로토콜과 HTML/XML을 이용하여 서비스를 제공한다. 반면 모바일 RFID 네트워크에서는 휴대 단말기의 특성에 따라 WAP방식 및 HTTP방식으로 서비스가 제공되고 있지만 단말기의 제약으로 인해 다양한 서비스 이용이 불가능 하다. 이와 같은 차이점으로 인해, 같은 RFID 네트워크 임에도 달구하고 논리적으로 두 개의 네트워크로 구분되며 서비스의 상호연동이 불가능 하다. 본 논문에서는 기존의 EPC 네트워크 구성을 따르며 모바일 RFID 네트워크의 구조변경없이 두 네트워크 간의 서비스 연동을 위한 구성 요소인 Application Server(AS)와 Mobile RFID Application Level Gateway(mRFID-ALG)를 제시한다.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.3
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• pp.91-98
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• 2013

Node which plays the role of cache server does not exist in the wireless ad-hoc network consisting of only mobile nodes. Even if it exists, it is difficult to provide cache services due to the movement of nodes. Therefore, the cooperative cache technique is necessary in order to improve the efficiency of information access by reducing data access time and use of bandwidth in the wireless ad-hoc network. In this paper, the whole network is divided into zones which don't overlap and master node of each zone is elected. General node of each zone has ZICT and manages cache data to cooperative cache and gateway node use NZCT to manage cache information of neighbor zone. We proposed security structure which can accomplish send and receive in the only node issued id key in the elected master node in order to prepare for cache consistent attack which is vulnerability of distributed caching techniques. The performance of the proposed method in this paper could confirm the excellent performance through comparative experiments of GCC and GC techniques.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.601-604
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• 2006

본 논문에서는 기업에서 관리되고 있는 설비 및 자산을 여러 가지 요인의 재난 위험으로부터 보호하는 것을 목적으로 하여 작업장 감지 시스템 WMS(Workshop Monitoring System)를 개발하였다. 이 시스템은 세 부분으로 구성된다. (1) 작업장 환경 자료를 수집하기 위한 센서 (2) 센서 데이타를 기록하고 SMS 메시지를 발생시키는 Status Logging Server (3) SMS Gateway 등으로 구성된다. 이러한 WMS는 각종 재해 발생시에 치명적인 손실을 초래 할 수 있는 시설들에 대해 즉각적인 조치를 위한 통보 시스템으로 활용할 수 있을 것이다.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.1
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• pp.65-75
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• 2003

The internet telephony service is one of the successful internet application services. VoIP is the key technology for the service to come true. VoIP uses H.323 or SIP as the standard protocol for the distributed multimedia services over the internet environment, in which QoS is not guaranteed. VoIP carries the packetized voice by using the RTP/UDP/IP protocol stack. The UDP-based internet services cause the data transmission problem to the users behind the internet firewall. So does the internet telephony service. The users are not able to listen the voices of the counter-parts on the public internet or PSTN. It makes the problem more difficult that the internet telephony service addressed in this paper uses only one UDP port number to send the voice data of all sessions from gateway to terminal node. In this paper, two schemes including the usage of dummy UDP datagrams, and the protocol conversion are suggested. The implementation of one of the schemes, the protocol conversion, and the performance evaluation are described in detail.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1151-1152
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• 2008

Recently, ubiquitous sensor network forms the self-organization network, and transfers the information among sensor nodes that have computing technology ability. In this paper, we design and implement U-IT system for monitoring the safety of metro railway and underground shopping malls. For this, we implement sensor nodes to support IEEE 802.15.4 wireless communication standard using low power. Also we implement USN gateway node system to transmit the collected data from sensor nodes to database server over CDMA cellular network.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.6
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• pp.369-377
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• 2016

Recently, many changes have been made to people's life patterns as the technological advances in the ICT industry. The fusion of smart phones and various IT technologies has brought people convenience and welfare. A typical example of such fusion is the smart home. However, the existing smart home systems are difficult to be changed or extended. So we design a new smart home system with extensibility that can easily adopt legacy appliances and be scaled up. Among a variety of smart home features, this paper deals with IoT Devices that are responsible for controlling power or transmitting and receiving sensing values, IoT Gateway that connects users and consumer electronics via Internet, and Smart Home Manager that monitors and controls these components in the proposed smart home system.