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Choo, Young-Yeol The Korea Contents Association 2006 International Journal of Contents Vol.2 No.4
The goal of Ambient Intelligence (AmI) is to build a smart environment for users where they are supported in some of their activities by many interaction mechanisms. The diversity of AmI characteristics requires special support from Operating Systems (OSes). In this paper, in order to support a conscious choice of an operating system for any specific AmI application, features requested by AmI systems were characterized and defined considering various applications. Then, characteristics of existing Operating Systems have been investigated in the context of AmI application support to relate their key characteristics to the typical requirements of AmI systems. Qualitative mapping table between AmI characteristics and as features has been proposed with an illustration of how to use it. As no as completely covers the range of characteristics required by AmI systems, challenging issues are summarized for the development of a new as and a product line of OSes.
Active Type Localization Scheme for Automatic Landing of Unmanned Helicopters
Young-yeol Choo,Daun Jung,Juneui Hong,Seongho Kang 한국멀티미디어학회 2010 한국멀티미디어학회 국제학술대회 Vol.2010 No.-
This paper describes a location tracking system to guide landing process of an Unmanned Helicopter (UMH) exploiting MIT Cricket nodes. The Cricket system operates in passive mode in that a listener attached to a moving device receives distance signals from several beacons located at fixed points on ground. Inevitably, this passive type of implementation causes large disturbances in measuring distances between beacons and the listener due to wind blow from propeller and turbulence of UMH body. To cope with this problem, we proposed active type of implementation for positioning a UMH. In this implementation, a beacon is set up at UMH body and four listeners are located at target ground position. A pair of Ultrasonic and RF signals from the beacon arrives at several listeners to calculate the position of the UMH. The distance signals among listeners are synchronized with a counter value appended to each distance signals from the beacon.
REAL-TIME COMMUNICATION SERVICE IN WIRELESS LOCAL AREA NETWORK
Young-yeol Choo,Sooyol Ok,Jang Woo Kwon 한국멀티미디어학회 2006 한국멀티미디어학회 국제학술대회 Vol.2006 No.-
This paper describes real-time communication support on IEEE 802.11 b Wireless Local Area Networks (WLANs). It has been known that IEEE 802.11 b is not suitable for applications requesting real-time communication service because CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance), which is medium access control scheme of IEEE802.11 b, is not be able to provide bounded medium access time. In this paper, we propose an algorithm to support real-time communication on a wireless local area network based on Timed Token Protocol. In this algorithm, we use a token to allocate bandwidth to each node so that the summation of each bandwidth allocation is the Target Token Rotation Time (TTRT). Upon receiving the token, a node consumes, at most, pre-allocated time for message transmission, and then passes it to the next node. If the node cannot consume the allocated time, the residual time is allocated to other nodes for non-periodic service using a timer which contains the unused time value and is appended to the token. This algorithm can always guarantee transmission of messages before their deadlines when network utilization is less than 50%
Performance Evaluation of Intranet Service for Real-Time Data of Instrumentation and Control Systems
Young-yeol Choo,Myoung-gyu Song 한국멀티미디어학회 2008 한국멀티미디어학회 국제학술대회 Vol.2008 No.-
This paper describes a message model based on XML to present real-time data from sensors and instruments at manufacturing processes for web service. For XML-based web service, XML schema was proposed for various instruments at steel-making plants. Considering transmission delay inevitably caused from increased message length and processing delay from transformation of raw data into defined format, its performance was evaluated by simulation. We suggested two implementation models for conducting the transformation function. In one model, transformation was done at an SCC (Supervisory Control Computer) after receiving realtime data from instruments. In the other model, transformation had been carried out at instruments before the data were transmitted to the SCC. Various tests had been conducted under different conditions of offered loads and data lengths and their results were described.
Development of Security Service for Mobile Internet Banking Using Personal Digital Assistants
Choo, Young-Yeol,Kim, Jung-In Korea Multimedia Society 2004 멀티미디어학회논문지 Vol.7 No.12
The fusion of Internet technology and applications with wireless communication provides a new business model and promises to extend the possibilities of commerce to what is popularly called mobile commerce, or m-commerce. In mobile Internet banking service through wireless local area network, security is a most important factor to consider. We describe the development of security service for mobile Internet banking on Personal Digital Assistants (PDAs). Banking Server and Authentication Server were developed to simulate banking business and to support certificate management of authorized clients, respectively. To increase security, we took hybrid approach in implementation: symmetric block encryption and public-key encryption. Hash function and random number generation were exploited to generate a secret key. The data regarding banking service were encrypted with symmetric block encryption, RC4, and the random number sequence was done with public-key encryption. PDAs communicate through IEEE 802.IIb wireless LAN (Local Area Network) to access banking service. Several banking services and graphic user interfaces, which emulatedthe services of real bank, were developed to verity the working of each security service in PDA, the Banking Server, and the Authentication Server.