• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.4
• /
• pp.768-774
• /
• 2007

This paper proposes how to reduce the amount of data transmitted in each sensor and cluster head in order to lengthen the lifetime of sensor network. This study proposes hierarchical filtering for reducing the sensor's energy dissipation. Hierarchical filtering is to divide sensor network by two tiers when filtering it. First tier performs filtering when transmitting the data from cluster member to cluster head, and second tier performs filtering when transmitting the data from cluster head to base station. This should increase the efficiency of filtering and decrease the inaccuracy of the data compared to the methods which enlarge the filter width to do more filtering.

• Journal of the Korea Society of Computer and Information
• /
• v.12 no.1 s.45
• /
• pp.73-82
• /
• 2007

This paper proposes how to reduce the amount of data transmitted in each sensor and cluster head in order to lengthen the lifetime of sensor network by data aggregation of the continuous queries. The most important factor of refuting the sensor's energy dissipation is to reduce the amount of messages transmitted. The method proposed is basically to combine clustering, in-network data aggregation and hierarchical filtering. Hierarchical filtering is to divide sensor network by two tiers when filtering it. First tier performs filtering when transmitting the data from cluster member to cluster head, and second tier performs filtering when transmitting the data from cluster head to base station. This method is much more efficient and effective than the previous work. We show through various experiments that our scheme reduces the network traffic significantly and increases the network's lifetime than existing methods.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2012.04a
• /
• pp.1101-1104
• /
• 2012

단어 필터링은 유해정보를 차단위한 기본적인 기능이다. 그러나 악의적인 사용자는 필터링 시스템을 우회하기 위하여 금지 단어에 의도적인 변형을 가한다. 이에 대응하기 위해 일정 오류를 허용하여 필터링을 수행하는 근사 단어 필터링이 있다. 근사 단어를 검색하기 위한 문자열 색인 방법으로는 주로 기준 단어(Pivot)을 이용한 유클리드 공간에의 사상을 이용하는데, 이는 단어 필터링에 응용하기에는 근본적인 구조상의 한계점이 있다. 본 논문에서는 필터링 대상이 되는 단어 집합 내에서 군집화를 수행하여 계층적인 자료구조를 구성하고, 단어 필터링을 위한 필터링 질의(Filtering query)를 정의한 뒤 그에 적합한 탐색 상의 적용에 관하여 설명한다. 실험 결과 기존의 기준 단어(Pivot)을 이용한 색인 기법에 비하여 16.9%~26.6%의 탐색 속도 향상을 확인할 수 있었다.

• Journal of Digital Contents Society
• /
• v.18 no.1
• /
• pp.141-147
• /
• 2017

Scalable extension of High Efficiency Video Coding (SHVC) standard uses the up-sampled residual data from the base layer to make a residual data in the enhancement layer. This paper describes an efficient algorithm for improving coding gain by using the filtered residual signal of base layer in the Scalable extension of High Efficiency Video Coding (SHVC). The proposed adaptive filter selection mechanism uses the smoothing and sharpening filters to enhance the quality of inter-layer prediction. Based on two filters and the existing up-sampling filter, a rate-distortion (RD)-cost fuction-based competitive scheme is proposed to get better quality of video. Experimental results showed that average BD-rate gains of 1.5%, 2.1%, and 1.7% for Y, U and V components, respectively, were achieved, compared with SHVC reference software 5.0, which is based on HEVC reference model (HM) 13.

• Journal of KIISE:Computer Systems and Theory
• /
• v.26 no.11
• /
• pp.1305-1317
• /
• 1999

NUMA 구조는 원격 메모리에 대한 접근이 불가피한 구조적 특성 때문에 상호 연결망이 성능을 좌우하는 큰 변수가 된다. 기존에 대중적으로 사용되던 버스는 물리적 확장성 및 대역폭에서 대규모 시스템을 구성하는 데 한계를 보인다. 이를 대체하는 고속의 지점간 링크를 사용한 링 구조는 버스가 가지는 확장성 및 대역폭의 한계라는 단점을 개선하였으나, 많은 클러스터가 연결되는 경우에는 전송 지연시간이 증가하는 문제점을 가지고 있다. 본 논문에서는 스누핑 프로토콜이 적용된 링 구조에서 클러스터 개수 증가에 따른 지연시간 증가의 문제점을 보완하기 위해 계층적 링 구조로의 확장을 제안하고, 이 구조에 효과적인 캐쉬 일관성 프로토콜을 설계하였다. 전역 링과 지역 링을 연결하는 브리지는 캐쉬 프로토콜을 관리하며 이 프로토콜에 의해 지역 링의 부하를 줄일 수 있도록 트랜잭션을 필터링하는 역할도 담당함으로써 시스템의 성능을 향상시킨다. probability-driven 시뮬레이터를 통해 계층적 링 구조가 시스템의 성능 및 링 이용률에 미치는 영향을 알아본다. Abstract Since NUMA architecture has to access remote memory, interconnection network performance determines performance of NUMA architecture. Bus, which has been used as popular interconnection network of NUMA, has a limit to build a large-scale system because of limited physical scalability and bandwidth. Ring interconnection network, composed of high-speed point-to-point link, made up for bus's defects of scalability and bandwidth. But, it also has problem of increasing delay as the number of clusters is increased. In this paper, we propose a hierarchical expansion of snoop-based ring architecture in order to overcome ring's defects of increasing delay. And we also design an efficient cache coherence protocol adopted to this architecture. Bridge, which connects local ring and global ring, maintains cache coherence protocol and does snoop-filtering which reduces local ring and cluster bus utilization. Therefore bridge can improve performance of this system. We analyze effects of hierarchical architecture on the performance of system and utilization of point-to-point links using probability-driven simulator.

• Journal of Korea Society of Industrial Information Systems
• /
• v.17 no.7
• /
• pp.111-118
• /
• 2012

Recently, most of firms have continuously released new products satisfying various needs of customers in order to increase market share. As a lot of products with various functionalities, prices and designs are released in the market, users have difficulties in choosing an appropriate product, especially for information technology driven devices. In case of digital cameras, inexperienced users spend a lot of time and efforts to find proper model for them. In this study, therefore, we design and implement a personalized recommendation system using analytic hierarchy process, one of the multi-criteria decision making techniques, and hybrid filtering combining content-based filtering and collaborative filtering to recommend a suitable product for inexperienced users of information technology devices.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2001.10b
• /
• pp.1279-1282
• /
• 2001

최근 인터넷의 급속한 사용 증가로 인해 전송 링크의 광대역 지원과 멀티미디어 트래픽의 QoS 보장 문제, 향상된 IP 서비스의 제공 문제 해결은 필수적이다. MPLS 기술은 IP의 유연성과 확장성을 제공할 수 있는 패러다임의 하나이다. MPLS 망의 경계에 위치하는 LER 은 링크 계층 뿐만 아니라 IP 계층에서도 패킷을 전달해야 한다. 본 논문에서는 하드웨어 포워딩 엔진을 갖는 MPLS LER에서, 패킷 필터링 기능을 지원하기 위해서 포워딩 엔진을 제어하기 위한 기법에 대해서 기술한다. 이러한 패킷 필터링 기능은 MPLS LER에 firewall 기능을 제공하는데 응용될 수 있다.

• KIPS Transactions on Computer and Communication Systems
• /
• v.8 no.9
• /
• pp.209-216
• /
• 2019

Publish-subscribe communication model is popular for various type of distributed applications because of its loosely coupled style connections. Among the various architecture style for publish-subscribe system, peer-to-peer architecture has been used for the mission critical application domain since it provides high scalability and real-timeness. On the other hand, to utilize the bandwidth of given networks, message filtering is frequently used to reduce the number of messages on the system. Even if P2P provides superior scalability, it is hard to apply filtering to the its messaging system because the filtering process should be done on the peer-side in P2P architecture that are usually done on the broker server in conventional pub/sub architecture. In this paper, we propose a hierarchical subscription management structure as well as message forwarding scheme for efficient data dissemination. Our proposed scheme reduces the number of received messages by filter-out un-wanted messages and offloading the message dissemination work to other subscribers to enhance the messaging throughput.

• Journal of Broadcast Engineering
• /
• v.1 no.1
• /
• pp.7-13
• /
• 1996

MASF is a kind of temporal filter proposed for noise reduction and temporal band limitation. MASF uses motion vectors to extract temporal information in spatial domain. Therefore, inaccurate motion information causes some distortions in MASF operation. Currently, bilinear interpolation after BMA(Block Matching Algorithm) is used for the motion estimation sheme of MASF. But, this method results in unreliable estimation when the object in image sequence has larger movement than the maximum displacement assumed in BMA or the input images are severely corrupted with noise. In order to i:;olve this problem, we analyse the effect of inaccurate motion on MASF and propose a hierarchical motion estimation algorithm based on the analysis results. Experimental results show that the proposed method produces reliable output under large motion and noisy situations.

• Journal of Intelligence and Information Systems
• /
• v.8 no.2
• /
• pp.139-157
• /
• 2002

The rapid growth of e-commerce has made both companies and customers face a new situation. Whereas companies have become to be harder to survive due to more and more competitions, the opportunity for customers to choose among more and more products has increased. So, the recommender systems that recommend suitable products to the customer have an important position in E-commerce. This research introduces collaborative filtering based recommender system which helps customers find the products they would like to purchase by producing a list of top-N recommended products. The suggested methodology is based on decision tree, product taxonomy, and association rule mining. Decision tree is used to select target customers, who have high possibility of purchasing recommended products. We applied the recommender system to a Korean department store. The methodology is evaluated with the analysis of a real department store case and is compared with other methodologies.