• Journal of Digital Contents Society
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• v.2 no.1
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• pp.9-19
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• 2001

Web robot is an important Internet software technology used in a variety of Internet application software which includes search engines. As Internet continues to grow, implementations of high performance Web robots are urgently demanded. For this, researches specially geared toward performance scalability of Web robots are required. Hoover, because researches are focused mostly on addressing issues related to commercial implementations, scientific researches and studies are not still made on the performance scalability. In this research, Ive choose a Web robot model implemented by fork-join based. multiprocesses. With respect to the model, we evaluate the effect on the collection efficiency that the timeout values set to requests from Web robots to Web servers have. Also, we analysed the behaviors of Web robots by comparing the execution time between the URL extraction and the uniqueness checking for the extracted URLs. as well as by comparing between the computation time and the network time. Based on the analysis result, we suggest the direction for the design of high performance Web robots.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1128-1135
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• 2010

The relay based cellular system has been introduced to provide the service to satisfy the user requirement. The main reasons of using relay station are to expand a service coverage and to increase a system throughput with satisfying the service requirement level. This paper proposes a new resource allocation algorithm which supports the users' throughput fairness and service coverage in the Fixed Relay Based Cellular system with OFDMA. The performance of proposed algorithm is compared with the performances of proportional fairness(PF) algorithm. The simulation result shows that the proposed algorithm increases the number of active users in the service coverage while paying small amount of throughput loss.

• Journal of Intelligence and Information Systems
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• v.14 no.2
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• pp.83-102
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• 2008

Ubiquitous computing requires timely supply of contextual information in order to upgrade decision quality. In this sense, this study is aimed at proposing a multi-dynamic decision support system for highly ill-structured problems. Especially, it is very important for decision makers in the ubiquitous computing to coordinate conflicts among local goals and global goal harmoniously. The proposed Multi-Dynamic Decision Support System (MDDSS) is basically composed of both central structure and distributed structure, in which central structure supports multi objects decision making and distributed structure supports individual decision making. Its hybrid architecture consists of decision processor, multi-agent controller and intelligent knowledge management processor. Decision processor provides decision support using contexts which come from individual agents. Multi-agent controller coordinates tension among multi agents to resolve conflicts among them. Meanwhile, intelligent knowledge management processor manages knowledge to support decision making such as rules, knowledge, cases and so on. To prove the validity of the proposed MDDSS, we applied it to an u-fulfillment problem system in which many kinds of decision makers exist trying to satisfy their own objectives, and timely adjustment of action strategy is required. Therefore, the u-fulfillment problem is a highly ill-structured problem. We proved its effectiveness with the aid of multi-agent simulation comprising 60 customers and 10 vehicles under three experimental modes.

• The Journal of the Korea Contents Association
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• v.22 no.1
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• pp.47-57
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• 2022

Demands for tangible contents using VR/AR technologies are much bigger as contactless services such as sports, physical activity, and fitness are expanded after COVID-19. A variety of technologies such as an offer and analysis of tangible data through a sensor technology, users' physical movement sensing through a motion recognition sensor, a real-time measurement of a physical skeleton point a multiple access to a real-time video, and AI training are being utilized as main technologies. This case study utilized motion recognition technologies as the study on tangible contents necessary for indoor-based physical education, sports, and fitness in the contactless environment and suggested cases to develop the physical measurement contents by design approach for the measurement assessment necessary for the development in tangible contents. The research established lists of the measurement assessment based on professionals' consultations within the measurement assessment function through the test to plan tangible contents and developed tangible contents by reflecting them as assessment measurement elements of tangible contents. The research can be utilized as the design approach of industrial companies which intend to develop tangible contents as well as reference cases of the research on contactless tangible contents for the sports and physical education.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1640-1650
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• 2010

To prepare for the network centric warfare, Korea Joint Tactical Data Link System(KJTDLS) has been developed by the South Korean military recently and its development is divided into two phases: basic and complete ones. Due to the limited bandwidth and low transmission efficiency of the developing KJTDLS (basic), lots of problems could be occurred when the TDMA protocol in Link-16 is applied. In this paper, a new dynamic TDMA frame structure for KJTDLS(basic) is proposed and the performance of the proposed is evaluated through the implementation of simulation.

• Convergence Security Journal
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• v.8 no.4
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• pp.51-56
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• 2008

A combination of VPNs and dial-up access, such as DSL and Cable, usually provides the cost-effective solution as the substitution of private networks on high-cost leased line. The business demand for high availability has increased with VPN spreading. This paper presents the schemes for a high availability of network access and a load balancing of network traffic in VPN gateways by using multiple links or multihoming capability based on active-active approach. The high availability and load balancing of network links can be achieved by duplicating external network access into multiple independent links. This can provide a continuous network connection to internal users even if one of the links is failed. Moreover, it can provide twice network bandwidth by distributing the traffic into the links. Static and dynamic algorithms are proposed as the load balancing algorithms.

• Journal of Advanced Navigation Technology
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• v.10 no.3
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• pp.268-275
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• 2006

The rapid proliferation of in-home and office information applications and services is driving the need for new wireless technologies enabling wideband short range multimedia communications. Due to the growing demand for higher quality media and faster wireless connections, several IEEE standardization groups are considering very high data rate alternatives physical layer(s) for Wireless Personal Area Network (WPAN). The Ultra Wide Band (UWB) multiple access technology based on very narrow pulse transmission, is one viable candidate for these applications providing very high bit rates services, low power consumption and accurate positioning capability. In this paper we provide a methodology to evaluate the UWB system BER performance in UWB wireless fading networks with power controlled UWB devices are considered. Results can be used to analyze the performance of a given network topology and to provide useful design ideas for an UWB home sensor network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4B
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• pp.677-686
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• 2010

In this paper, we propose the virtual interface management scheme on the multi-mode mobile node for supporting multiple connections to various access networks in fixed mobile convergence (FMC) networks. The proposed scheme supports the virtualization of multiple physical network interfaces by presenting only the virtual interface to beyond IP layers and hiding physical network interfaces from them. In the proposed scheme, only one IP address is allocated to virtual interface without any IP allocations to physical network interfaces. Therefore, the proposed scheme does not change its IP address and keep it during the vertical handover, so that it can support the seamless handover of real-time multimedia services among heterogeneous access networks. The proposed scheme is implemented on the multi-mode mobile node with multiple network interfaces by using NDIS (Network Driver Interface Specifications) libraries. Through the mobility test-bed and the test application of virtual interface, we evaluate and analyze the performance of the proposed scheme.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.143-148
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• 2001

Digital documentation is now becoming a must throughout a building process including design, construction, inspection, procurement and even facility management. The Internet is a backbone of such process, and web-based information exchange is the standard among other mainstream technologies. The current information management techniques, however, is heavily dependant on the server-side processing, which naturally results in the overload of the overall system. This paper proposes an XML-based approach in order to resolve such problems. A VE system was developed to demonstrate the efficiency of the XML solution, in term of efficient VE data management and fast decision making. also in this paper suggests 1) introduce XML based DBMS to improve data management efficiency and 2) introduce Mobile Computing to improve data accessibilities on sites.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12A
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• pp.1311-1319
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• 2007

This paper presents the VHDL implementation procedure of the passive RFID tag operating in Ultra High Frequency. The operation of the tag compatible with the EPCglobal Class1 Generation2(GEN2) protocol is verified by timing simulation after synthesis and implementation. Due to the reading range with relatively large distance, a passive tag needs digital processor which facilitates faster decoding, encoding and state transition for enhancement of an interrogation rate. In order to satisfy linking time, the pipe-line structure is used, which can minimize latency to serial input data stream. We also propose the sampling strategy to decode the Preamble, the Frame-sync and PIE symbols in reader commands. The simulation results with the fastest data rate and multi tags environment scenario show that the VHDL implemented tag performs faster operation than GEN2 proposed.