• Title/Summary/Keyword: hit ratio

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Design of Push Agent Model Using Dual Cache for Increasing Hit-Ratio of Data Search (데이터 검색의 적중률 향상을 위한 이중 캐시의 푸시 에이전트 모델 설계)

  • Kim Kwang-jong;Ko Hyun;Kim Young-ja;Lee Yon-sik
    • Journal of the Korea Society of Computer and Information
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    • v.10 no.6 s.38
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    • pp.153-166
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    • 2005
  • Existing single cache structure has shown difference of hit-ratio according to individually replacement strategy However. It needs new improved cache structure for reducing network traffic and providing advanced hit-ratio. Therefore, this Paper design push agent model using dual cache for increasing hit-ratio by reducing server overload and network traffic by repetition request of persistent and identical information. In this model proposes dual cache structure to do achievement replace gradual cache using by two caches storage space for reducing server overload and network traffic. Also, we show new cache replace techniques and algorithms which executes data update and delete based on replace strategy of Log(Size) +LRU, LFU and PLC for effectiveness of data search in cache. And through an experiment, it evaluates Performance of dual cache push agent model.

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Fuzzy Relevance-based Transcoding for Differentiated Streaming Media Service in the Proxy System (프록시 시스템에서 차별화된 스트리밍 미디어 서비스를 위한 퍼지 적합도 기반 트랜스 코딩)

  • Lee, Chong-Deuk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.6
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    • pp.2785-2792
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    • 2011
  • Such problems as delay, congestion, and crosstalk in the proxy system degrade not only QoS (Quality of Service) but responsiveness and reliability of the streaming media service. To solve this problem this paper proposed a FRTP (Fuzzy Relevance-based Transcoding Proxy) mechanism. The proposed FRTP mechanism analyzes fuzzy similarity for partitioned segment versions of media objects to create a FRTG (Fuzzy Relevance-based Transcoding Graph). Created FRTG determines the transcoding for partitioned media object segment versions. Determined transcoding improves DSR (Delay Saving Ratios), CHPR (Cache Hit Precision Ratio), and CHRR (Cache Hit Recall Ratio). The proposed mechanism is simulated to evaluate such performance parameters as DSR, CHPR, and CHRR. Simulation results shows that the proposed mechanism outperforms in DSR, CHPR and CHRR compared with the other existing mechanisms.

MLC-LFU : The Multi-Level Buffer Cache Management Policy for Flash Memory (MLC-LFU : 플래시 메모리를 위한 멀티레벨 버퍼 캐시 관리 정책)

  • Ok, Dong-Seok;Lee, Tae-Hoon;Chung, Ki-Dong
    • Journal of KIISE:Computing Practices and Letters
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    • v.15 no.1
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    • pp.14-20
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    • 2009
  • Recently, NAND flash memory is used not only for portable devices, but also for personal computers and server computers. Buffer cache replacement policies for the hard disks such as LRU and LFU are not good for NAND flash memories because they do not consider about the characteristics of NAND flash memory. CFLRU and its variants, CFLRU/C, CFLRU/E and DL-CFLRU/E(CFLRUs) are the buffer cache replacement policies considered about the characteristics of NAND flash memories, but their performances are not better than those of LRD. In this paper, we propose a new buffer cache replacement policy for NAND flash memory. Which is based on LFU and is taking into account the characteristics of NAND flash memory. And we estimate the performance of hit ratio and flush operation numbers. The proposed policy shows better hit ratio and the number of flush operation than any other policies.

Research on optimal FCL (Frequently Called List) table sizes in a circuit-switched network including wireless subscribers (무선 가입자를 포함한 회선교환망에서의 최적의 FCL (Frequently Called List) 테이블 크기에 관한 연구)

  • 김재현;이종규
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.10
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    • pp.1-9
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    • 1994
  • In this paper, we have studied optimal FCL(Frequently Called List) table sizes in a grid topology circuit-switched network including wireless subscribers. The FCL table gives the position information of a destination subscriber for a call. When the call is generated in a node, this call is routed by the referenced position information of the destination subscriber in FCL table. In this paper, we have proposed an efficient routing algorithm, mixed FSR(Flood Search Routing) and DAR(Dynamic Adaptive Routing), considering moving wireless subscribers. Also, we have simulated hit ratio and incorrect ratio as performance parameters, consequently proposed the object function composed of table search time, hit ratio, incorrect ratio, FSR time and DAR time, and derived the optimal FCL table size by using it.

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Web Caching using File Type (파일 타입을 이용한 웹 캐싱)

  • Lim, Jae-Hyun;Lee, Jun-Yeon
    • The KIPS Transactions:PartC
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    • v.9C no.6
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    • pp.961-968
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    • 2002
  • This paper proposes a new access method which is to considered the high variability in World Wide Web and manage the web cache space. Instead of using a single cache, we divide a cache and store all documents according to their file types. Proposed method was compares with current cache management policies using LFU, LRU and SIZE base algorithm. Using two different workload, we show the improvement hitting ratio and byte hitting ratio through simulating on the file type caching.

Preference-Based Segment Buffer Replacement in Cluster VOD Servers (클러스터 VOD서버에서 선호도 기반 세그먼트 버퍼 대체 기법)

  • Seo, Dong-Mahn;Lee, Joa-Hyoung;Bang, Cheol-Seok;Lim, Dong-Sun;Jung, In-Bum;Kim, Yoon
    • Journal of KIISE:Computer Systems and Theory
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    • v.33 no.11
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    • pp.797-809
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    • 2006
  • To support the QoS streams for large scale clients, the internal resources of VOD servers should be utilized based on the characteristics of the streaming media service. Among the various resources in the server, the main memory is used for the buffer space to the media data loaded from the disks and the buffer hit ratio has a great impact upon the server performance. However, if the buffer data with high hit ratio are replaced for the new media data as a result of the number of clients and the required movie titles are increased, the negative impact on the scalability of server performance is occurred. To address this problem, the buffer replacement policy considers the intrinsic characteristics of the streaming media such as the sequential access to large volume data and the highly disproportionate preference to specific movies. In this paper, the preference-based segment buffer replacement policy is proposed in the cluster-based VOD server to exploit the characteristics of the streaming media. Since the proposed method reflects both the temporal locality by the clients' preference and the spatial locality by the sequential access to media data, the buffer hit ratio would be improved as compared to the existing buffer replacement policy. The enhanced buffer hit ratio causes the fact that the performance scalability of the cluster-based VOD server is linearly improved as the number of cluster nodes is increased.

Development of surface defect inspection algorithms for cold mill strip using tree structure (트리 구조를 이용한 냉연 표면흠 검사 알고리듬 개발에 관한 연구)

  • Kim, Kyung-Min;Jung, Woo-Yong;Lee, Byung-Jin;Ryu, Gyung;Park, Gui-Tae
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.365-370
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    • 1997
  • In this paper we suggest a development of surface defect inspection algorithms for cold mill strip using tree structure. The defects which exist in a surface of cold mill strip have a scattering or singular distribution. This paper consists of preprocessing, feature extraction and defect classification. By preprocessing, the binarized defect image is achieved. In this procedure, Top-hit transform, adaptive thresholding, thinning and noise rejection are used. Especially, Top-hit transform using local min/max operation diminishes the effect of bad lighting. In feature extraction, geometric, moment, co-occurrence matrix, histogram-ratio features are calculated. The histogram-ratio feature is taken from the gray-level image. For the defect classification, we suggest a tree structure of which nodes are multilayer neural network clasifiers. The proposed algorithm reduced error rate comparing to one stage structure.

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High-intensity Fitness Training Among a National Sample of Male Career Firefighters

  • Jahnke, Sara A.;Hyder, Melissa L.;Haddock, Christopher K.;Jitnarin, Nattinee;Day, R. Sue;Carlos Poston, Walker S.
    • Safety and Health at Work
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    • v.6 no.1
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    • pp.71-74
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    • 2015
  • Obesity and fitness have been identified as key health concerns among USA firefighters yet little is known about the current habits related to exercise and diet. In particular, high-intensity training (HIT) has gained increasing popularity among this population but limited quantitative data are available about how often it is used and the relationship between HIT and other outcomes. Using survey methodology, the current study evaluated self-reported HIT and diet practice among 625 male firefighters. Almost one-third (32.3%) of participants reported engaging in HIT. Body composition, as measured by waist circumference and percentage body fat, was significantly related to HIT training, with HIT participants being approximately half as likely to be classified as obese using body fat [odds ratio (OR) = 0.52, 95% confidence interval (CI) = 0.34-0.78] or waist circumference (OR = 0.61, 95% CI = 0.37-0.98). Those who engaged in HIT were more than twice as likely as those who did not (OR = 2.24, 95% CI = 1.42-3.55) to meet fitness recommendations. Findings highlight directions for future prevention and intervention efforts.

Distributed Construction of the Recrystallization Topology and Efficient Searching in the Unstructured Peer-to-Peer Network (재결정 위상의 분산적 구성과 비구조적 피어투피어 망에서의 효율적 검색)

  • Park, Jae-Hyun
    • Journal of KIISE:Information Networking
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    • v.35 no.4
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    • pp.251-267
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    • 2008
  • In this paper, we present a distributed topology control algorithm for constructing an optimized topology having a minimal search-time in unstructured peer-to-peer network. According to the proposed algorithm, each node selects the best nodes having higher hit-ratio than other nodes as many as the number being exponentially proportional to the hit-ratio of the node itself, and then it connects to them. The ensemble behavior of the proposed algorithm is very similar to the recrystrallizing phenomenon that is observed in nature. There is a partial order relationship among the hit-ratios of most nodes of constructed topology. Therefore once query message visits a node, it has a higher hit-ratio than the node that was visited last by the message. The query message even sent from freeloader can escape to the node having high hit-ratio by one hop forwarding, and it never revisits any freeloader again. Thus the search can be completed within a limited search time. We also propose the Chain-reactive search scheme using the constructed topology. Such a controlled multicasting reduces the query messages by 43 percent compared to that of the naive Gnutella using broadcasting, while it saves the search time by 94 percent. The search success rate of the proposed scheme is 99 percent.

A New Item Recommendation Procedure Using Preference Boundary

  • Kim, Hyea-Kyeong;Jang, Moon-Kyoung;Kim, Jae-Kyeong;Cho, Yoon-Ho
    • Asia pacific journal of information systems
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    • v.20 no.1
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    • pp.81-99
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    • 2010
  • Lately, in consumers' markets the number of new items is rapidly increasing at an overwhelming rate while consumers have limited access to information about those new products in making a sensible, well-informed purchase. Therefore, item providers and customers need a system which recommends right items to right customers. Also, whenever new items are released, for instance, the recommender system specializing in new items can help item providers locate and identify potential customers. Currently, new items are being added to an existing system without being specially noted to consumers, making it difficult for consumers to identify and evaluate new products introduced in the markets. Most of previous approaches for recommender systems have to rely on the usage history of customers. For new items, this content-based (CB) approach is simply not available for the system to recommend those new items to potential consumers. Although collaborative filtering (CF) approach is not directly applicable to solve the new item problem, it would be a good idea to use the basic principle of CF which identifies similar customers, i,e. neighbors, and recommend items to those customers who have liked the similar items in the past. This research aims to suggest a hybrid recommendation procedure based on the preference boundary of target customer. We suggest the hybrid recommendation procedure using the preference boundary in the feature space for recommending new items only. The basic principle is that if a new item belongs within the preference boundary of a target customer, then it is evaluated to be preferred by the customer. Customers' preferences and characteristics of items including new items are represented in a feature space, and the scope or boundary of the target customer's preference is extended to those of neighbors'. The new item recommendation procedure consists of three steps. The first step is analyzing the profile of items, which are represented as k-dimensional feature values. The second step is to determine the representative point of the target customer's preference boundary, the centroid, based on a personal information set. To determine the centroid of preference boundary of a target customer, three algorithms are developed in this research: one is using the centroid of a target customer only (TC), the other is using centroid of a (dummy) big target customer that is composed of a target customer and his/her neighbors (BC), and another is using centroids of a target customer and his/her neighbors (NC). The third step is to determine the range of the preference boundary, the radius. The suggested algorithm Is using the average distance (AD) between the centroid and all purchased items. We test whether the CF-based approach to determine the centroid of the preference boundary improves the recommendation quality or not. For this purpose, we develop two hybrid algorithms, BC and NC, which use neighbors when deciding centroid of the preference boundary. To test the validity of hybrid algorithms, BC and NC, we developed CB-algorithm, TC, which uses target customers only. We measured effectiveness scores of suggested algorithms and compared them through a series of experiments with a set of real mobile image transaction data. We spilt the period between 1st June 2004 and 31st July and the period between 1st August and 31st August 2004 as a training set and a test set, respectively. The training set Is used to make the preference boundary, and the test set is used to evaluate the performance of the suggested hybrid recommendation procedure. The main aim of this research Is to compare the hybrid recommendation algorithm with the CB algorithm. To evaluate the performance of each algorithm, we compare the purchased new item list in test period with the recommended item list which is recommended by suggested algorithms. So we employ the evaluation metric to hit the ratio for evaluating our algorithms. The hit ratio is defined as the ratio of the hit set size to the recommended set size. The hit set size means the number of success of recommendations in our experiment, and the test set size means the number of purchased items during the test period. Experimental test result shows the hit ratio of BC and NC is bigger than that of TC. This means using neighbors Is more effective to recommend new items. That is hybrid algorithm using CF is more effective when recommending to consumers new items than the algorithm using only CB. The reason of the smaller hit ratio of BC than that of NC is that BC is defined as a dummy or virtual customer who purchased all items of target customers' and neighbors'. That is centroid of BC often shifts from that of TC, so it tends to reflect skewed characters of target customer. So the recommendation algorithm using NC shows the best hit ratio, because NC has sufficient information about target customers and their neighbors without damaging the information about the target customers.