• Journal of Internet Computing and Services
• /
• v.5 no.6
• /
• pp.1-10
• /
• 2004

A web robot is a software that has abilities of tracking and collecting web documents on the Internet(l), The performance scalability of recent web robots reached the limit CIS the number of web documents on the internet has increased sharply as the rapid growth of the Internet continues, Accordingly, it is strongly demanded to study on the performance scalability in searching and collecting documents on the web. 'Design of web robot based on Multi-Agent to speed up documents collection ' rather than 'Sequentially executing Web Robot based on the existing Fork-Join method' and the results of analysis on its performance scalability is presented in the thesis, For collection speedup, a Multi-Agent based web robot performs the independent process for inactive URL ('Dead-links' URL), which is caused by overloaded web documents, temporary network or web-server disturbance, after dividing them into each agent. The agents consist of four component; Loader, Extractor, Active URL Scanner and inactive URL Scanner. The thesis models a Multi-Agent based web robot based on 'Amdahl's Law' to speed up documents collection, introduces a numerical formula for collection speedup, and verifies its performance improvement by comparing data from the formula with data from experiments based on the formula. Moreover, 'Dynamic URL Partition algorithm' is introduced and realized to minimize the workload of the web server by maximizing a interval of the web server which can be a collection target.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.12
• /
• pp.3069-3077
• /
• 1997

This paper is concerned with a new paradigm for parallel evaluation of linear recursion rules which contain transitive dependency in a shared-nothing parallel architecture. For parallel evaluation of rules, we consider a shared-nothing parallel architecture that consists of a set of nodes and a message passing network to these nodes. An evaluation of normalized rules is a computation of the proof theoretic meaning of a collection of rules. We shall here define normalized recursion rules which contain transitive dependency, present an equivalent expression for the rule, propose a paradigm for Parallel evaluation of normalized rule based on the equivalent expression using join, partition, and transitive closure operations, and analyze response-time complexity.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.3
• /
• pp.1416-1428
• /
• 2016

In this paper, we address the channel zapping time problem of video streaming services based on HTTP Live Streaming (HLS) on smart Over-The-Top Set-Top Boxes (OTT STBs). Experimental analysis of the channel zapping time, show that smart OTT STBs inevitably suffer from the accumulated zapping time through channel change request, Internet Group Management Protocol (IGMP) leave/join, synchronization delay, video buffer delay, and STB processing delay when providing HLS services. As a practical solution for the zapping time reduction, an adaptive buffering method is proposed. The proposed method exploits two adaptive buffers added to the basic HLS player. These two adaptive buffers are responsible for constantly buffering previous and next channels relative to the current channel. Implementation and test results show that a stable zapping time less than one second can be achieved even under diverse video bitrate changes and varying network conditions by the proposed adaptive buffering method.

• The KIPS Transactions:PartB
• /
• v.12B no.7 s.103
• /
• pp.775-782
• /
• 2005

In this paper, we propose multicast technique in order to reduce the required network bandwidth by n times, by merging the adjacent multicasts depending on the number of HENs (Head-End-Nodes) n that request the same video. Allowing new clients to immediately join an existing multicast through patching improves the efficiency of the multicast and offers services without any initial latency. A client might have to download data through two channels simultaneously, one for multicast and the other for patching. The more the frequency of requesting the video is, the higher the probability of caching it among HENs increases. Therefore, the requests for the cached video data can be served by HENs. Multicast from server is generated when the playback time exceeds the amount of cached video data. Since the interval of multicast can be dynamically expanded according to the popularity of videos, it can be reduced the server's workload and the network bandwidth. We perform simulations to compare its performance with that of conventional multicast. From simulation results, we confirm that the Proposed multicast technique offers substantially better performance.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.7B
• /
• pp.679-689
• /
• 2006

Delivering multicast stream is one of the cost-saving approach in the large scale VOD environment. Because implementing VCR-like interactions for user's convenience in the multicast streaming system involves complex problems, we need the proper solutions for them. In this paper, we propose a hybrid scheme which uses the general P2P and the patching scheme with the Collaborative Interaction Streaming Scheme(CISS). CISS provides jumping functionability to the appropriate multicast session after VCR-like interaction in the environment in which multiple peers transmit VCR-like interaction streams to the VCR-like functionability request node to reduce the loads generated by frequent join or departure of peers at the multicast tree during providing VCR-like functionability. Therefore, with the proposed scheme we can distribute network traffic and reduce control overhead and latency. And to evaluate the performance of proposed scheme we compare it in the aspect of the performance of streaming delivery topology, control overhead and streaming quality with P2Cast[10] and DSL[11]. The simulation result shows that proposed P2Patching reduces about 30% of process overhead and enhances about $25{\sim}30%$ of streaming quality compared with DSL.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.11
• /
• pp.1-12
• /
• 2009

Mobbing is going the rounds through a society rapidly and Military is not exception. Because mobbing of military is expressed not only psychology exclusion that is mobbing pattern of adult society but also sometimes psychologic and physical mobbing, is possible to join serious military discipline like a suicide and outrageous behavior. Specially military try to protect occurrence of victims that is public service through various rules and management plan but victims is going on happen. It means importance of grasp not only current mobbing victims but also potential mobbing victims better than preparation of various rules and management plans. Therefore this paper extracts seven factors and fifty attributes that are related to this matter mobbing. Next, by using Gunwoo's Social Network Service that is made for oneself and expressing extracting factors as '1' if they are related me or not '0'. And apply similarity function(Dice's coefficient) to attributes summation included in factors to calculate similarity between the users. Third, calculate optimizing weight choosing factors included attributes by applying neural network algorithm of SPSS Clementine and propose Mobbing Value(MV) Algorithm through this total summation. Finally through this algorithm which will contribute to efficient personnel management, we can grasp mobbing victims and tentative mobbing victims.

• KIPS Transactions on Software and Data Engineering
• /
• v.1 no.3
• /
• pp.159-168
• /
• 2012

Relation in the new IT environment, such as the SNS, Cloud, Web3.0, has become an important factor. And these relations generate a transaction. However, existing relational database and graph database does not processe graph structure representing the relationships and transactions. This paper, we propose the technique that can be processed concurrently graph structures and transactions in a scalable complex network system. The proposed technique simultaneously save and navigate graph structures and transactions using the Topic Maps data model. Topic Maps is one of ontology language to implement the semantic web(Web 3.0). It has been used as the navigator of the information through the association of the information resources. In this paper, the architecture of the proposed technique was implemented and design using Cassandra - one of column type NoSQL. It is to ensure that can handle up to Big Data-level data using distributed processing. Finally, the experiments showed about the process of storage and query about typical RDBMS Oracle and the proposed technique to the same data source and the same questions. It can show that is expressed by the relationship without the 'join' enough alternative to the role of the RDBMS.

• Journal of the Korean association of regional geographers
• /
• v.6 no.1
• /
• pp.29-49
• /
• 2000

The purposes of this study are to identify the characteristics of inner-city industrial community and to analyse the subsistence mode of small manufacturing enterprises in the industrial community in Taegu Metropolitan area. The case study area, Nowon 1. 2-ga dong, is the typical inner city industrial community, adjacent to old industrial complex, which was recently transformed from semi -industrial to semi-residential zoning district. Now there are many old one story housing, newly constructed multi stories housing and many small factories of metal and machinery products. The conflicts of between residents and small business owners are not serious but latent. The subsistence mode of small manufacturing enterprises in this area is characterized as the network production system. The main attributes of this mode are local integration, horizontal subcontracting and strong industrial linkages in production processes and transactions. These transactions are mainly made by face-to-face contacts. The small business owners' local social networks are seen as series of units which are interconnected through various types of social and business relations. They exchange business information as using social networks. In addition, the majority of them join local social clubs with their local business counterpartners. Finally, the locational advantages of inner-city industrial community are production network, different industrial linkages and characteristic industrial milieu such as social solidarity, informal labor market and incubator effects. But these advantages are being challenged from the contradiction between capital and laned property and the urban gentrification policy. Accordingly, there should be positive redevelopment policy considering the subsistence mode of small business in these areas.

• The KIPS Transactions:PartC
• /
• v.10C no.5
• /
• pp.625-634
• /
• 2003

More than a decade after its initial proposal, deployment of IP Multicast has been limited due to the problem of traffic control in multicast routing, multicast address allocation in global internet, reliable multicast transport techniques etc. Lately, according to increase of multicast application service such as internet broadcast, real time security information service etc., overlay multicast is developed as a new internet multicast technology. In this paper, we describe an overlay multicast protocol and propose fast join mechanism that considers switching of the tree. To find a potential parent, an existing search algorithm descends the tree from the root by one level at a time, and it causes long joining latency. Also, it is try to select the nearest node as a potential parent. However, it can't select the nearest node by the degree limit of the node. As a result, the generated tree has low efficiency. To reduce long joining latency and improve the efficiency of the tree, we propose searching two levels of the tree at a time. This method forwards joining request message to own children node. So, at ordinary times, there is no overhead to keep the tree. But the joining request came, the increasing number of searching messages will reduce a long joining latency. Also searching more nodes will be helpful to construct more efficient trees. In order to evaluate the performance of our fast join mechanism, we measure the metrics such as the search latency and the number of searched node and the number of switching by the number of members and degree limit. The simulation results show that the performance of our mechanism is superior to that of the existing mechanism.

• Convergence Security Journal
• /
• v.16 no.6_2
• /
• pp.53-60
• /
• 2016

Security measures for the current insurance crime has focused on the capture oriented and reactive response in the screening stage of insurance payments. However, since leaving the damages that can not be healed by post-punishment, it is necessary to take measures to prevent the insurance crimes in advance. In this paper, I would like to try to identify problems through analyzing the characteristics and cases of the insurance crimes, and to present alternatives to it. The problems with the current insurance system that causes the insurance crimes are, First, When signing the insurance contract, it is too inattentive to confirm about the credit status of the policyholder, duplicate join or not, whether voluntarily sign up etc. Second, a thorough investigation or criminal charges in case of insurance accident is not being done properly. Third, information exchange and management to malicious policyholders is not being done properly. Therefore, in order to guard people from insurance crimes, First, it should strengthen the audit of such credit conditions, accident experiences in the insurance contract at the policyholders. Second, we need to block insurance crimes in advance through the continuous upgrades of insurance fraud analysis systems and social network. Third, it is necessary to strengthen the surveillance systems for the insurance crimes by the information sharing.