Yoseop Woo

Automated keyword extraction using category correlation of data

In this paper, we proposed a system that extracts keywords using thesaurus which contains data saved by category. The system enhances precision of extracted keywords based on considering correlation of the category. 30 Living Modified Organisms related experimental documents were used in order for performance measurement of the system. The proposed system showed better precision than frequency-based system by 47 % and thesaurus-based system by 18 %.

A Seamless Multimedia Service in Wireless Network

This paper presents a seamless multimedia service in WLAN. In this paper, the environment of WLAN for seamless video service consists of a switching agent (SA), some access points (AP) and mobile nodes (MNs). The SA supports handover mechanism for MNs when they move one AP to another, and retransmits video streams from video server to the requesting AP. The proposed handover mechanism needs additional 2-byte as IP header which is used for an identification number (ID#) of AP that the MNs are joined. The SA changes the path of successive video streams using the ID# generated when the MN moves to a specific AP. The proposed system can support seamless video service without cutoff and reconnection to video server according to the handover.

VOD service using web-caching technique on the head-end- network

To provide fluent on-demand services on Internet, the VOD servers have to possess a powerful processing ability and the network needs a vast bandwidth. The more clients request service, the more these resources are required. This paper presents a web-caching technique for providing fluent VOD services on Internet. This technique adopts some caches in the Head-End-Network that consists of a Switching-Agent (SA), some Head-End-Nodes and many clients. This technique distributively stores video streams in the order of request on some HENs which request an identical video item. Thus, storing streams on each HEN are different. When the client requests service for cached video items, connecting HEN receives streams from HENs which stored them and transmits them to client. These procedures are performed under the control of SA. Therefore this technique distributes the load of HENs, leads to equiloaded HEN and protects data duplication among HENs.

Automatic Extension of Korean Predicate-Based Sub-categorization Dictionary from Sense Tagged Corpora

Analyzing sentences of Korean language, it is found that situation, meaning, and context perform an important role rather than syntactical characteristics. Thus it is difficult to disambiguate word sense by rule-based method, such as context-free grammar, only. In this study, sense-tagged corpora was semi-automatically constructed with the use of predicate-based sub-categorization dictionary. In this process, the information on the frequency of predicate-based sub-categorization patterns, the information on the collocation of predicates and nouns, and the information on the statistic cooccurence of declinable words could be obtained. Based on this information, the method of automatic extension of sub-categorization dictionary is suggested.

A study on the predicate prediction using symbols in augmentative and alternative communication system

This study generally is purposed to develop a mobile augmentative and alternative communication system (hereinafter referred to as “a mobile AAC system”). Also the device is aimed as a mobile AAC system for HCI, allowing a handicapped person to make a general communication with others in a free and convenient manner. This study specifically presents a method of predicting predictions, which contributes to reducing the size of the mobile system. This method includes selecting vocabulary and classifying it by domains so as to meet the characteristics of the mobile AAC communication, using a noun thesaurus for semantic analysis, and building a sub-category dictionary. Predicting predicates by selecting symbols in accordance with this method is tested and the utility thereof is confirmed.

Path-Connectivity for Mobile Digital Library Service in Hybrid Ad-Hoc Network

This paper deals with path-connectivity for digital library system in ad-hoc network. One of the critical problems for service in (hybrid) ad-hoc network is service shutting down frequently due to multi-hop connectivity drawback according to mobile node(MN)s’ movement. To solve this problem we adopt a technique that a few MNs having 1-less hop manage a number of MNs having 1-more hop, and access points that has cache to reduce delay in hybrid ad-hoc network. Therefore this proposed technique has a robustness for connection break up because it has multiple paths to infra-network(AP).

Video Service Algorithm Using Web-Cached Technique in WLAN

This paper presents the strategy for video service using caching technique in WLAN. The environment of WLAN includes mobile nodes(MN) and an access point(AP) that have memory for store video clips transmitted from AP and video server, respectively. The operation for the proposed system has two modes, the 1 st mode is AP mode that all MNs are serviced through AP, and the 2 nd mode is an ad-hoc mode that is serviced only through other MNs without AP connecting. The operation of ad-hoc mode is that the requesting MN is serviced directly from the video clip cached on other MN without the connection to AP or multimedia server(MS). Otherwise the proposed system uses AP mode that requesting MN is serviced under the control of AP, thus MN connects to AP’s cache or MS.

Icon language-based auxiliary communication system interface for language disorders

The icon language interface is designed to provide the people with language disabilities with more smooth and convenient communication environment than the traditional keyboard-based input system. In order for that, vocabulary commanding tendencies and characteristics of proto-corpus built upon the frequently-used conversation sections will be analyzed, and the Korean languages vocabulary and their meanings applied to the icons will be retrieved by the use of morpheme, phrase and semantic analysis techniques. The icon types to be intuitively recognized and communicable by users are selected, and they are matched with the retrieved Korean vocabulary and meanings. In order to create a relevant situation to communicate from the relations between neighboring icons, the icon language is formed through the each definition of icon languages vocabulary, grammar rules, parts of speech and semantic system.

Implementation and usability evaluation of AAC system for handicapped persons

This study generally is purposed to implementation and usability evaluation of augmentative and alternative communication system (hereinafter referred to as an “AAC system”). Also the device is aimed as an AAC system using symbols for HCI, allowing a handicapped person to make a general communication with others in a free and convenient manner. This study specifically presents a method of predicting predictions, which contributes to reducing the size of the AAC system. This method includes selecting vocabulary and classifying it by domains so as to meet the characteristics of the AAC communication, using a noun thesaurus for semantic analysis, and building a sub-category dictionary. Accordingly, this study has verified the system by applying it to linguistically handicapped persons with different kinds of handicaps two times.

The multicast system for seamless live multimedia in WLAN

This paper proposes the multicast system for seamless live multimedia in a wireless network. The multicast technique for live multimedia and a part of handover mechanism are performed on the buffered multicasting/switching agent (BMSA) in a wireless local area network (WLAN). The rest of the handover mechanism is performed on access points (APs). This paper uses a new Internet Protocol (IP) header that is composed of three AP numbers (AP_#s) and 1-bit overwrite bit (OB) to perform seamless service. The three AP_#s support a smooth handover for solving the cutoff service when mobile nodes (MNs) move among other APs in WLAN. The overhead for a new IP header (2 bytes long) is negligible in comparison with multimedia service, and the overhead for the multicast group address (MGA) packet that is used in the transmission of MGA is only 11 bits. The MGA packet is composed of two AP_#s, an overwriting group address (OGA) bit, and MGA. We confirmed that the proposed multicast system can decrease the number of channels required, the delay of service, and the possibility of packet duplication because multicast is not provided on the multimedia server but on the BMSA in WLAN.