• Proceedings of the Korean Information Science Society Conference
• /
• 2003.04d
• /
• pp.331-333
• /
• 2003

본 논문에서는 802.11을 기반으로 한 무선 링크에서 인터넷 상의 대표적인 전송계층 프로토콜인 TCP(Transmission Control Protocol)와 HDP(User Datagram Protocol)의 성능을 비교한다. 또한 이들 프로토콜이 무선 환경에서 보이는 문제점을 지적하고 원인을 분석한다. 무선 네트워크의 용량은 유선 네트워크와 다르며, 따라서 유선 네트워크 용량을 기반으로 설계된 TCP는 불안정하게 작동한다. 본 논문에서는 주목할만한 전송 프로토콜의 병목현상을 나타내는 원인으로 MAC(Medium Access Control)에 의해 채널을 잡기 위한 경쟁이 심각함과 전송 계층 프로토콜의 네트워크 용량 예측이 올바르지 않음을 지적하고, TCP와 HDP를 비교하여 무선 망에서도 네트워크 상황에 적응하는 기법이 중요함을 확인한다.

• Journal of the Korean BIBLIA Society for library and Information Science
• /
• v.17 no.1
• /
• pp.305-324
• /
• 2006

The requirements to use high speed internet under wireless environment are increased. To satisfy the requirements. the WiBro service combining high speed of wired internet service with mobility of wireless internet service will be launched as an alternative. This paper reviews and analyzes its overview, features, and comparison with existing mobile internet and wireless LAN in the information providing aspect. This paper also proposes how to adapt mobile information service and how to satisfy the requirements to construct mobile library based on the WiBro service. With the current problems in mobile-based information services provided by libraries. especially this paper proposes information service areas. considerations to provide information services, and service provisioning method based on the WiBro service.

• Journal of Internet Computing and Services
• /
• v.6 no.6
• /
• pp.13-22
• /
• 2005

This paper aims to develop a system for converting web contents to mobile contents that can be used on mobile devices. Since web contents generally consist of pop-up ad windows, a bunch of unnecessary images and useless links, it is difficult to efficiently display them on common mobile devices that have lower bandwidth and memory, as well as much smaller screen, than the online environment. It is also troublesome for mobile device users to directly access contents. Thus, there has been a great demand for a new method for extracting useful and adequate contents from web documents, and optimizing them for use on mobile phones, In the paper, a system based on WAP 2,0 and XHTML Basic, which is a content creation language adopted for WAP 2,0, has been suggested. The system is designed to convert web contents by using the conversion rules of the existing filtering method after making the size of web documents smaller. The adopted conversion rules use the XHTML Basic's module units so that modification and deletion can be carried out with ease. In addition, it has been defined in a XSL document written in XSLT to maintain the extensibility of conversion and the validity of documents, In order to allow it to efficiently work together with WAP l.X's legacy services, the system has been built in a way that can have modules, which analyze information about CC/PP profiles and mobile device headers.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.8 no.5
• /
• pp.35-44
• /
• 2008

In this study, to establish a web-based bridge monitoring system with wireless sensor network environment, we constructed microminiaturized sensor based wireless communication techniques and micro processing, databases for data combination and administration, variable control programs and processors for transferring data by internet. Then those data are measured and analyzed by the constructed bridge monitoring system with wireless sensors. To evaluate the practicability of the bridge monitoring system with wireless sensor, we compared the values measured in the tests with wire sensor under same conditions. The results show that the trend of the data obtained from the monitoring systems with wire sensors and wireless sensors was very similar but the some lost data in the communication process with wireless sensor network environment. And through laboratory and field tests, the effectiveness and the applicability of the proposed methods were verified.

• Journal of KIISE:Information Networking
• /
• v.32 no.5
• /
• pp.603-614
• /
• 2005

The wireless LAN environment using Mobile IP is constructed and managed to be connected with Ethernet based wired networks. However, there have been many problems with wireless networks using Mobile IP. Some important facts on network performance have not been considered when introducing wireless LAN by Mobile IP to wired networks. In this paper, we suggest schemes which can solve problems on Handover latency caused by the asymmetrical connectivity of the Access Router at applying the HMIPv6 and on binding updates due to the MN frequent movement. Our proposed schemes can reduce network latency by using the HMIPv6 architecture with a virtual router layer, and reduce communication overhead by interchanging information of the MN movement between routers. Our schemes are expected to assist in constructing a more real and effective wireless LAN environment based on the HMIPv6 and FMIP.

• Journal of the Korean Geographical Society
• /
• v.47 no.2
• /
• pp.268-281
• /
• 2012

In spite of the usefulness of migration statistics in spatially understanding social processes and identifying social effects of spatial processes, services and analyses of the statistics have been restricted due to the complexity of their data structure. In addition, flow mapping functionality which is a useful method to explore and visualize the migration statistics has yet to be fully represented in modern GIS applications. Given this, the purpose of this research is to demonstrate the possibility of flow mapping and the exploratory spatial analysis of the migration statistics in a Web GIS environment. For this, the characteristics of the statistics were examined from database, GIS, and cartographic perspectives. Then, O-D structure of the migration statistics was converted to spatial data appropriate to f low mapping based on the characteristics. The interface of Web GIS is specialized the migration statistics and provides exploratory visualization by allowing dynamic interactions such as spatial focusing and attribute filtering.

• The Journal of the Korea Contents Association
• /
• v.10 no.11
• /
• pp.38-47
• /
• 2010

DMX512 protocol controls a lighting system for outdoor lightings and stage lightings. But lighting systems using DMX512 protocol based wired needs expensive cost in installation, maintain, repair. And it has restrictions about control channel numbers and its ranges. Also, it needs additional equipments for the control of lighting systems which installed on wide area. In this paper, we propose wireless control technique and a ZDMX module for lighting systems on wide area based on DMX512 protocol. Our technique solves problems of DMX512 protocol, and it can control lighting systems on wide area effectively. We developments the LED lighting system using ZDMX modules and we have confirmed the suitability of our technique for real environment.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2002.04b
• /
• pp.1057-1060
• /
• 2002

대부분의 전자상거래 시스템이 유선 인터넷과 HTML(Hypertext Markup Language)을 기반으로 하고 있다. 그러나, 무선 단말기의 대량 보급으로 무선 인터넷이 인터넷의 새로운 패러다임을 주도하고 있으며, 효율적인 전자상거래를 위하여 HTML기반의 시스템이 XML(eXtended Markup Language) 기반으로 대치되는 과정에 있다. 무선 인터넷은 이동전화나 PDA(Personal Digital Assistant) 등 소형 무선 단말기 상에서 인터넷을 이용할 수 있도록 해주는 프로토콜의 총칭으로 정의되는 WAP(Wireless Application Protocol)과 같은 규약을 이용하여 다양한 서비스를 시간 및 공간의 제약을 받지 않고 무선 장치를 통하여 제공한다. 그리고, XML은 정보나 자료를 처리하는 데 있어 공통의 표준을 적용시킬 수 있고, 이 기종 응용프로그램간의 상호 작용을 중대시키고, 조직간에 정보 공유를 향상시킬 수 있다. 본 논문에서는 이러한 WAP과 XML의 장점을 결합한 전자상거래 시스템을 소개한다. 제안된 시스템은 WAP을 이용하여 무선뿐만 아니라 유선으로 실시간 정보 공유를 가능하게 하였고, 기존 시스템에서의 데이터베이스 시스템을 XML데이터로 대체시킴으로 인하여 데이터 저장을 위한 시공간의 비용을 절감시켰다. 뿐만 아니라 XML데이터의 사용으로 메타데이터를 생성 및 가공할 수 있는 방법을 구현하였다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2015.10a
• /
• pp.606-609
• /
• 2015

Lawful Interception (LI)이란 합법적인 형태의 통신내용 및 관련 정보의 수집활동을 말한다. 최근의 4G LTE 기반의 이 기종 통신망에서의 합법적 감청은 전통적인 유선 및 3G 네트워크 중심의 감청기법 이외의 새로운 기법과 표준이 필요한 실정이다. 특히, LTE와 같이 User Equipment (UE)가 네트워크상에서 핸드오버를 통해 자유롭게 이동하거나, 3G와 같은 이 기종 망에서의 연결을 포함한 다른 사업자의 새로운 지역에서의 네트워크 연결이 보장되는 형태의 환경에서의 연속적 감청을 보장하는 것은 합법적 감청분야의 중요한 이슈중의 하나이다. 따라서, 본 논문에서는 국내의 4G-LTE망을 중심으로 기존의 3G 망을 자유롭게 이동하는 네트워크 도메인과 IMS/SIP 기반의 서버의 연속성을 보장하는 서비스 도메인 영역에서의 합법적 감청 기법을 제안한다. 본 논문에서 제안하는 기법은 이 기종 무선망과 유선망이 혼재된 네트워크에서의 IMS/SIP 기반 서비스의 이동성을 감지하여 합법적 감청의 연속성을 보장하기 위한 기법을 포함하고 있다.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.6
• /
• pp.1025-1032
• /
• 2022

In this paper, the TDMA-based PoE wireless multi-IP camera transmission system using wireless communication technology is developed to reduce the burden of construction costs caused by the existing wired-based CCTV surveillance system and IP camera system. It intends to design and implement the long-distance wireless transmission technology of video. The transmission/reception prototype of the line IP transmission system and the wireless multi-IP camera transmission terminal and image acquisition device (SB-200) for the proposed related technology were described.