• Journal of Communications and Networks
• /
• v.14 no.1
• /
• pp.75-90
• /
• 2012

Thin client computing trades local processing for network bandwidth consumption by offloading application logic to remote servers. User input and display updates are exchanged between client and server through a thin client protocol. On wireless devices, the thin client protocol traffic can lead to a significantly higher power consumption of the radio interface. In this article, a cross-layer framework is presented that transitions the wireless network interface card (WNIC) to the energy-conserving sleep mode when no traffic from the server is expected. The approach is validated for different wireless channel conditions, such as path loss and available bandwidth, as well as for different network roundtrip time values. Using this cross-layer algorithm for sample scenario with a remote text editor, and through experiments based on actual user traces, a reduction of the WNIC energy consumption of up to 36.82% is obtained, without degrading the application's reactivity.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.10c
• /
• pp.135-137
• /
• 2000

무선 인터넷 시장의 급속한 발전으로 인해 컨텐츠에 대한 사용자들의 다양한 요구가 증가되고 있고, 그로인해 WML과 WML Script를 개발자가 실제와 같은 상황에서 편리하게 개발할 수 있는 환경이 필요하게 되었다. 본 논문에서는 CP(Content Provider)들이 쉽고 편리하게 WML(Wireless Markup Language) 컨텐츠(Content)를 개발, 브라우징하기 위한 WAP(Wireless Application Protocol) Emulator의 설계와 구현에 대하여 기술한다. WAP Emulator는 WML 파싱(parsing) 모듈과 인터페이스(Interface)모듈, 그리고 Data Send/Receive 모듈로 구성되며, 디코딩(Decoding)된 WML 문서를 파싱하여 브라우저로 보여준다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.5
• /
• pp.1087-1095
• /
• 2014

A recent major development in computer technology is the advent of the wearable computer system that is based on human-centric interface technology trends and ubiquitous computing environments. Wearable computer systems can use the wireless universal serial bus (WUSB) that refers to USB technology that is merged with WiMedia PHY/MAC technical specifications. In this paper, we focus on an integrated system of the wireless USB over the IEEE 802.15.6 wireless body area networks (WBAN) for wireless wearable computer systems supporting U-health services. And a communication structure that can differentiate QoS of U-health WBAN and WUSB traffic with different priorities is proposed for WUSB over IEEE 802.15.6 hierarchical protocol. In our proposal and performance evaluation, throughputs of U-health WBAN and WUSB traffic are analyzed under single and multiple QoS classes to evaluate the effectiveness of proposed QoS differentiating structure in WUSB over IEEE 802.15.6.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.4A
• /
• pp.365-372
• /
• 2007

In IEEE 802.11b wireless network, stations synchronize themselves to the beacons periodically sent by the access point(AP) when they are running in low power mode. In case of missing beacon due to noise or traffic from neighboring wireless network stations must be awake until they get the next beacon, which causes energy consumption in stations. In this paper, we propose a scheme searching next beacon consuming little energy. The problems of missing beacon in low power mode of IEEE 802.11b wireless interface are described and a new method to reduce energy consumption is proposed. The proposed method is simulated with the network simulator, ns2, and compared with the low power mode of the IEEE 802.11b. The result measured in terms of station's wakeup time shows some enhancement in energy consumption when some errors occur in receiving frames.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.10
• /
• pp.1905-1913
• /
• 2006

The researches about the hardware and the software implementing ubiquitous sensor network have great rush in recent years. This paper deals the development of a sensor node with the dual interface which also has an RF wireless interface while has an Bluetooth interface used widely in present. This sensor node includes a Atmeg32 microcontroller, a Bluetooth module, a RF module. a temperature-humidity sensor. and I also develop the F/Ws controlling each modules with C language using GCC compiler. The sensor node developed can reaches 15m with Bluetooth interface and 60m with RF interface. It works stably with the voltage above 5V and it consumes currents 21mA average in idle mode, 63mA average in active mode.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.05a
• /
• pp.752-755
• /
• 2009

Recently, the production process system is largely composed automatic system using the wired network. The production process system using wired network has disadvantages that take place expense when the installed and inspected production of equipment was replaced. The each equipment happens to repair cost for control and management in production processes. In this paper, the industrial equipment that applied for IEEE 802.15.4(ZigBee) technology solves a complicated space at the plant. And then when the industrial equipments replace wired network with wireless network, this paper studied its user interface.

• Proceedings of the KIEE Conference
• /
• 2006.07d
• /
• pp.1913-1914
• /
• 2006

Modem Industrial control systems tend to adopt a variety of intelligent wireless device controllers to interface front-end computers with active components of the industrial device. Some of the intelligent control systems come equipped with a wireless SMS(Simple Message Service) interface giving an opportunity to use fault alarm Interlock system. Immediately send warning or alert messages to Mobile devices or remote users. Real time monitoring the SMS systems by Mobile devices. Control systems remotely by mobile devices in emergency situation. In order to provide against system fault, SMS Mobile System will enable system administrator to promptly access, monitor and control the system whenever users want and wherever users are, by utilizing wireless Internet and mobile devices. This paper presents the Mobile SMS system for PAL Control System.

• Proceedings of the KIEE Conference
• /
• 2006.10c
• /
• pp.288-290
• /
• 2006

This paper presents the real-time water tank wireless control in a ship using duplex RF modules and PLC(Programmable logic Controller). The purpose of this paper is developing HMI(Human Machine Interface) for automation equipments. The system can low a cost because long wires are no more used. Analog signals of the water gauge and flow meter are changed to discrete signals by the micro-processor. The PLC checks the volume of water and runs On or Off of the valve and pump. Duplex RF modules send and receive data between the water tank and control room. Everywhere the Internet is used, operators are able to check the status of the system by the web-server.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.10 no.5
• /
• pp.167-172
• /
• 2010

This paper is to implement HSDPA-CPE that can provides WiFi terminal with wireless Internet service through the connection to HSDPA wireless network. This system aims to support HSDPA interface in upstream, and WiFi and 100Mbps Ethernet interface in downstream. So, this system can provide multiple Internet customers with wireless Internet service by using WiFi terminal in subway, car, ship, and so on, and WiFi terminals that be registered in HSDPA service can be connected to Internet.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
• /
• v.9 no.2
• /
• pp.42-47
• /
• 2010

In next generation wireless network environment, various different wireless access technologies exist and multi-interface systems which can provide various services in one terminal are required. So far there have been many studies only on the power control part of multi-interface systems. Therefore, the study of network connection considering Qos between different networks is necessary in order for various services to be operated in integrate wireless networks. This paper proposes a pre-authentication and network connection mechanism rather than power control part.