• Journal of the Korea Society of Computer and Information
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• v.22 no.3
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• pp.9-16
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• 2017

In recent computing systems, LRU replacement policy has been widely used because it can be simply implemented and applicable to most programs. However, if the working set size of the program is bigger than the actual cache size, LRU replacement policy may occur thrashing problem. Thrashing problem means that cache blocks are consistently replaced without re-referencing in the cache. This paper proposes a new cache management scheme to solve the thrashing problem in the second-level cache. The proposed scheme measures per set reuse frequency using EAF structure to find thrashing sets. When the cache miss occurs, it tests whether the address of the missed block is stored or not. If the address of the missed block is stored, it means that the recently evicted block is re-requested, so the reuse frequency is predicted high. In this case, the corresponding counter of the set is increased. When the counter value is bigger than the threshold value, we assume that the corresponding set shows high reuse frequency. The proposed scheme assigns the set with high reuse frequency to the additional small size cache to keep the blocks in the cache for a long time. Our experimental results show that the proposed scheme improves the IPC by 3.81% on average.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.7
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• pp.1610-1623
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• 2013

In-network caching is a key component of information-centric networking (ICN) for reducing content download time, network traffic, and server workload. Data center network (DCN) is an ideal candidate for applying the ICN design principles. In this paper, we have evaluated the effectiveness of caching placement and replacement in DCN with butterfly-topology. We also suggest a new cache placement policy based on the number of routing nodes (i.e., hop counts) through which travels the content. With a probability inversely proportional to the hop counts, the caching placement policy makes each routing node to cache content chunks. Simulation results lead us to conclude (i) cache placement policy is more effective for cache performance than cache replacement, (ii) the suggested cache placement policy has better caching performance for butterfly-type DCNs than the traditional caching placement policies such as ALWASYS and FIX(P), and (iii) high cache hit ratio does not always imply low average hop counts.

• Journal of the Semiconductor & Display Technology
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• v.22 no.3
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• pp.106-111
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• 2023

The importance of load-to-use latency has been highlighted as state-of-the-art computing cores adopt deep pipelines and high clock frequencies. The cascaded cache was recently proposed to reduce the access cycle of the L1 cache by utilizing differences in latencies among banks of the cache structure. However, this study assumes the cache is comprised of SRAM, making it unsuitable for direct application to non-volatile memory-based systems. This paper proposes a novel mechanism and structure for lowering dynamic energy consumption. It inserts monitoring logic to keep track of swap operations and write counts. If the ratio of swap operations to total write counts surpasses a set threshold, the cache controller skips the swap of cache blocks, which leads to reducing write operations. To validate this approach, experiments are conducted on the non-volatile memory-based cascaded cache. The results show a reduction in write operations by an average of 16.7% with a negligible increase in latencies.

• Journal of the Korea Society of Computer and Information
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• v.13 no.1
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• pp.227-232
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• 2008

General web caches save documents temporarily into themselves on the basis of those documents. And when a corresponding document exists within the cache on user's request. web cache sends the document to corresponding user. On the contrary. when there is not any document within the cache, web cache requests a new document to the related server to copy the document into the cache and then turn it back to user. Here, web cache uses a replacement policy to change existing document into a new one due to exceeded capacity of cache. Typical replacement policy includes document-based LRU or LFU technique and other various replacement policies are used to replace the documents within cache effectively. However. these replacement policies function only with regard to the time and frequency of document request. not considering the popularity of each web site. Based on replacement policies with regard to documents on frequent requests and the popularity of each web site, this paper aims to present the document replacement policies with regard to the popularity of each web site, which are suitable for latest network environments to enhance the hit-ratio of cache and efficiently manage the contents of cache by effectively replacing documents on intermittent requests by new ones.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.5
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• pp.412-421
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• 2009

Due to the physical characteristics of NAND flash memory, overwrite operations are not permitted at the same location, and therefore erase operations are required prior to rewriting. These extra operations cause performance degradation of NAND flash memory file system. Since it also has an upper limit to the number of erase operations for a specific location, frequent erases should reduce the lifetime of NAND flash memory. These problems can be resolved by delaying write operations in order to improve I/O performance: however, it will lower the cache hit ratio. This paper proposes a policy of page management using double cache for NAND flash memory file system. Double cache consists of Real cache and Ghost cache to analyze page reference patterns. This policy attempts to delay write operations in Ghost cache to maintain the hit ratio in Real cache. It can also improve write performance by reducing the search time for dirty pages, since Ghost cache consists of Dirty and Clean list. We find that the hit ratio and I/O performance of our policy are improved by 20.57% and 20.59% in average, respectively, when comparing them with the existing policies. The number of write operations is also reduced by 30.75% in average, compared with of the existing policies.

• The Journal of the Korea Contents Association
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• v.3 no.3
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• pp.63-73
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• 2003

Today, in exponential growth of internet, the importance of file caching which could reduce the sun load, the volume of network traffic, and the latency of response has emerged. Actually, in one network, the traffic has reduced by using the cache and this means that file caching can improve the internet environment by cost a fraction of link upgrades. In this paper, we address a dynamic cache group configuration policy, to solve the scalable problem. The simulation result shows that the cache group using our proposal policy reduces the latency of response time and it means that out cache group configuration is more scalable than the static cache configuration.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1113-1120
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• 2021

Content Central Network (CCN) appeared to improve network efficiency by transforming IP-based network into content name-based network structures. Each router performs caching mechanism to improve network efficiency in the CCN. And the cache replacement policy applied to the CCN router is an important factor that determines the overall performance of the CCN. Therefore various studies has been done relating to cache replacement policy of the CCN. In this paper, we proposed a cache replacement policy that improves the limitations of the LFU policy. The proposal algorithm applies real-time producer popularity-based variables. And through experiments, we proved that the proposed policy shows a better cache hit ratio than existing policies.

• International Journal of Contents
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• v.3 no.1
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• pp.14-18
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• 2007

General replacement policy includes document-based LRU or LFU technique and other various replacement policies are used to replace the documents within cache effectively. But, these replacement policies function only with regard to the time and frequency of document request, not considering the popularity of each web site. In this paper, we present the document replacement policies with regard to the popularity of each web site, which are suitable for modern network environments to enhance the hit-ratio and efficiently manage the contents of cache by effectively replacing documents on intermittent requests by new ones.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.52-58
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• 2013

Replacement policy is one of the key factors determining the effectiveness of a cache. The LRU replacement policy has remained the standard for caches for many years. However, the traditional LRU has ineffective performance in zero-reuse line intensive workloads, although it performs well in high temporal locality workloads. To address this problem, We propose a new replacement policy; DCR(Dynamic Counter based Replacement) policy. A temporal locality of workload dynamically changes across time and DCR policy is based on the detection of these changing. DCR policy improves cache miss rate over a traditional LRU policy, by as much as 2.7% at maximum and 0.47% at average.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.3
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• pp.59-66
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• 2020

Content Centric Network(CCN) with architecture that is completely different from traditional host-based networks has emerged to address problems such as the explosion of traffic load in the current network. Research on cache replacement policies is very active to improve the performance of CCN with the characteristics that all routers cache on the network. Therefore, this paper proposes a cache replacement policy suitable for situations in which popularity is constantly changing, taking into account the actual network situation. In order to evaluate the performance of the proposed algorithm, we experimented in an environment where the popularity of content is constantly changing, and confirmed that we are superior to the existing replacement policy through comparing hit rates and analyzing server load.