• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.95-96
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• 2007

Recently, flexible communication is issued because of implementation of both communicable small and equipment wireless networks environment. Similarly diverse small equipment, from wireless LAN to sensor, have different data format as network access. So, middleware that support flexible communication is necessary. Also it is important that information format of diverse sensor(raw data) converts to information usable in application.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.4
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• pp.229-235
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• 2014

This paper presents an environmental navigation system which provides a guidance to the users of smart bicycle for a pollution-free route during their travel. The smart bicycle operates as a sensor node being composed of a distributed wireless sensor network over the whole urban area. Several environmental sensors measuring the amount of dust, CO, $CO_2$, $NO_2$ in the air are built into the smart bicycle to estimate the level of air pollution in the located area. Each smart bicycle sends/receives the measured sensor data and the city pollution map to/from the centralized server, which leads the bike-riders to a healthy route by providing the environmental navigation information. The proposed idea and its implementation give a useful insight on various application services with the distributed smart bicycles.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.843-845
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• 2011

Due to the short lifetime of the battery-based sensor network, study on the environmental energy-harvesting sensor network is being performed widely. In this paper, we analyze the system-level requirements on the sensor node which is needed for the efficient solar-powered wireless sensor network for the target application. In addition, we explain how the HW/SW components of our real solar-powered sensor node can satisfy the requirements mentioned above.

• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.3
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• pp.1-8
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• 2008

Recently, a great many people are concerned about promoting their health because medical science and scientific technology has become much larger and more develop. Thus, the person who interested in health wants to confirm his condition whatever he may take a meal or exercise. But it is disappointed of our expectation. By reason that many people doesn't know what changes will occur in their body. In this paper, we are going to introduce our Health Care Managing System which could display a physical variation, in addition, we will also propose how to control serial data from wireless sensors. We implemented this system using ZigbeX and Java application.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.46-63
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• 2012

The concept of an "intelligent building" received significant attention from academic, industry and standard development organizations when technically termed a building management system (BMS). Wireless sensor networks (WSNs) and their recent development enhanced monitoring and control applications for the building's areas. This paper surveys and analyzes advantages of the main current and emerging approaches that may be fit for BMS. Specifically, we discuss challenges including interoperability, integration, overhead, and bandwidth limitation of WSNs in BMS. Based on analyses, we highlight the advantages of an IP-based and RESTful architecture approach as the most suitable solution for BMS using WSNs (BMS-WSN). The paper also describes our future direction and design for BMS-WSN based on these advantages. The purpose is to enable interaction of users with BMS-WSN in the same way as with any website while ensuring energy efficiency. A test-bed implementation and evaluation of a BMS application is also introduced in this paper to demonstrate the feasibility and benefits of IP-based and RESTful architecture for BMS.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.412-414
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• 2003

모바일 표준 플랫폼 WIPI(Wireless Internet Platform for Interoperability)는 하드웨어 독립적으로 설계되어 어떠한 무선단말기에도 사용가능하며 개발언어인 C와 자바를 선택적으로 사용할 수 있는 국내 무선인터넷 표준 플랫폼이고 WAP2.0(Wireless Application Protocol) 규격은 XHTML의 사용으로 유.무선 인터넷의 통합 컨텐츠 제공이 가능한 무선 응용프로토룰이다. 본 논문에서는 WIPI 표준 플랫폼에서 단말기의 무선인터넷 활용을 위해 XHTML을 마크업 언어로 채용한 WAP2.0 규격의 마이크로 브라우저 원형(Prototype)을 설계하여 구현하였고 WIPI 시뮬레이터를 사용하여 응용프로그램으로 구현된 마이크로 브라우저의 동작실험을 함으로써 WIPI 표준 플랫폼을 위한 WAP2.0마이크로 브라우저의 활용 가능성을 제시한다.

• Journal of Information Processing Systems
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• v.13 no.5
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• pp.1320-1330
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• 2017

Wireless sensor networks for forest monitoring are typically deployed in fields in which manual intervention cannot be easily accessed. An interesting approach to extending the lifetime of sensor nodes is the use of energy harvested from the environment. Design constraints are application-dependent and based on the monitored environment in which the energy harvesting takes place. To reduce energy consumption, we designed a power management scheme that combines dynamic duty cycle scheduling at the network layer to plan node duty time. The dynamic duty cycle scheduling is realized based on a tier structure in which the network is concentrically organized around the sink node. In addition, the multi-paths preserved in the tier structure can be used to deliver residual packets when a path failure occurs. Experimental results show that the proposed method has a better performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.678-681
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• 2009

WiFi는 무선인터넷 접속(Wireless LAN) 방식의 하나로서 이동성, 설치용이성, 유연성 등으로 인하여 널리 사용되고 있다. 더욱이 기존 다양한 디지털 기기들이 WiFi 기반의 application을 탑재하여 각종 온라인 콘텐츠를 이용할 수 있게 하면서 점차 보편적인 인터넷 접속수단으로서 변모하고 있는 상황이다. WiFi의 편리성으로 인하여 기업, 공공기관, 교육기관 등에서 네트워크 구축에 WiFi를 사용하는데 그 추세가 개인부문에서 기업부문으로 확산되고 있다. 하지만 유선인터넷이 케이블이라는 매체를 통해 연결되어 외부와 차폐된데 비해 WiFi는 주파수를 매개로하기 때문에 네트워크 접근이 용이하며 이로인해 보안이 취약해 질 수 있다는 것이다. 이로 인하여 일명 워드라이빙(war driving)이라 불리는 서비스의 무단사용뿐만 아니라 악의를 가진 네트워크 침입이 가능해져 개인정보나 사유재산이 침해 가능성이 높다고 할 수 있다. 이에 본 연구에서는 해외의 WiFi의 보안관련 법제도를 살펴보고 이로부터 국내 WiFi보안을 위한 대안을 제시하고자 한다.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1138-1144
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• 2008

To study the feasibility of applying wireless communication technology to the control of train for the effective control of train and for the reduction of cost and time to construct the necessary infra structure, we investigate into the application of the existing commercial WCDMA network to CBTC (communication-based train control) to grasp the obstacles and propose the solutions to circumvent them. The obstacles can be categorized into the hand-off problem, the interference problem near the stations, and the problem of radio shadow areas. We propose, as solutions, the cell overlap method and multi-terminal approach for the hand-off problem, the cell sectoring method for the interference problem, and establishment of new base stations along the railroad both to provide the wireless train control and communication service to the customers on the train which was otherwise impossible because of the shadowing effect.

• Electronics and Telecommunications Trends
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• v.33 no.6
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• pp.118-128
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• 2018

With the massive increase in bandwidth for wireless communications, free space optical (FSO) communication has attracted significant interest owing to its outstanding strengths over conventional radio frequency wireless communication such as a wide bandwidth, unlicensed spectrum, low power consumption, small size, electromagnetic interference immunity, long-range propagation, and improved security. In recent years, FSO technology has been studied intensively for use in terrestrial and underwater autonomous and unmanned mobile systems, a rapidly growing application area, including robots, drones, unmanned aerial vehicles, autonomous vehicles, unmanned trains, and unmanned submarines. In this report, we review the recent trends and key technologies for the mobile FSO system, and introduce our drone-based mobile FSO system, which is currently under development.