• ETRI Journal
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• v.40 no.1
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• pp.61-71
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• 2018

In this study, we developed hybrid control algorithms in smart base stations (SBSs) along with devised communication, caching, and computing techniques. In the proposed scheme, SBSs are equipped with computing power and data storage to collectively offload the computation from mobile user equipment and to cache the data from clouds. To combine in a refined manner the communication, caching, and computing algorithms, game theory is adopted to characterize competitive and cooperative interactions. The main contribution of our proposed scheme is to illuminate the ultimate synergy behind a fully integrated approach, while providing excellent adaptability and flexibility to satisfy the different performance requirements. Simulation results demonstrate that the proposed approach can outperform existing schemes by approximately 5% to 15% in terms of bandwidth utilization, access delay, and system throughput.

• The Transactions of the Korea Information Processing Society
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• v.6 no.12
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• pp.3642-3651
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• 1999

In this paper, we propose a new caching scheme for continuous media data where the buffer allocation unit is divided into two modes : interval and object. All of objects' access patterns are monitored and based on the results of monitoring, a request for an object is decided to cache its data with either interval mode or object mode. The results of our simulation show that our proposed caching scheme is better than the existing caching algorithms such as interval caching where the access patterns of the objects are changed with time.

• The Journal of Information Technology
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• v.5 no.4
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• pp.9-21
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• 2002

In data broadcasting environments, the server periodically broadcasts data items in the database through the broadcast channel. When each client wants to access any data item, it should monitor the broadcast channel and wait for the desired item to arrive. Client data caching is a very effective technique for reducing the time spent waiting for the desired item to be broadcasted. This paper proposes a new client cache management scheme, named 2Q-CF, to reduce this waiting time and evaluate its performance on the basis of a simulation model. The performance results indicate that 2Q-CF scheme shows superior performances over LRU-CF and CF in the average response time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10C
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• pp.798-804
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• 2008

This paper proposes a low-power circuit for detecting and correcting L2 cache errors during microprocessor data image processing. A simplescalar-ARM is used to analyze input and output data by accessing the microprocessor's L2 cache during image processing in terms of the data input and output frequency as well as the variation of each bit for 32-bit processing. The circuit is implemented based on an H-matrix capable of achieving low power consumption by extracting bits with small and large amounts of variation and allocating bits with similarities in variation. Simulation is performed using H-spice to compare power consumption of the proposed circuit to the odd-weight-column code used in a conventional microprocessor. The experimental results indicated that the proposed circuit reduced power consumption by 17% compared to the odd-weight-column code.

• The Transactions of the Korea Information Processing Society
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• v.5 no.6
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• pp.1652-1659
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• 1998

To provide performance gains by reducing the operand referencing latency and data cache bandwidth requirements, we present an operand reference prediction cache (ORPC) which predicts operand value and address translation during the instruction fetch stage. The prediction is verified in the early stage, and thus it minimizes the performance penalty caused by the misprediction. Through the trace-driven simulation of six benchmark programs, the performance improvement by proposed three aRPC stmctures (OfiPC1, OfiPC2. ORPC3)is analysed and validated.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.2
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• pp.131-136
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• 2008

From the reciprocal connection by this Internet network researchs about the efficiency improvement of the whole system is accomplished with the method which reduces delays in message transmission. From here, we will do a comparative study between the user data program protocol (UDP) and the zero copy which does not use the buffer cache to fine out the valid method to improve the efficiency. In this thesis, I will change the message copy from execution process of the buffer cache of the TCP/IP on Unix OS with process on Linux OS. The object of conversion is to show you that the zero copy which doesn't use the buffer cache from transfer control class improves the communication efficiency.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.916-927
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• 2010

In this paper, we analyze the performance of the parity cache enabled RAID level-5 via the simulation. This RAID system consists of the DDR memory-based storage devices. To do this, we develop the simulation model and suggest the basic performance analysis data which we want to get via the simulation. And we implement the simulator based on the simulation model and execute the simulator. From the result of the simulation, we expect that the parity cache enabled RAID level-5 configured by the DDR memory based storage devices has the positive effectiveness to the enhancing of the storage system performance if the storage access patterns of applications are tuned.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.1
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• pp.30-43
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• 2008

Memory reference instructions such as loads or stores are critical factors that limit the processing power of processor. The prefetching technique is an effective way to reduce the latency caused from memory access. However, excessively aggressive prefetch leads to cache pollution so as to cancel out the advantage of prefetch. In this study, four filtering schemes have been compared and evaluated which dynamically decide whether to begin prefetch after referring a filtering table to decrease cache pollution. First, A bi-states scheme has been shown to analyze the lock problem of the conventional scheme, this scheme such as conventional scheme used to be N:1 mapping, but it has the two state to 1bit value of each entries. A complete state scheme has been introduced to be used as a reference for the comparative study. A block address lookup scheme has been proposed as the main idea of this paper which exhibits the most exact filtering performance. This scheme has a length of the table the same as the bi-states scheme, the contents of each entry have the fields the same as the complete state scheme recently, never referenced data block address has been 1:1 mapping a entry of the filter table. Experimental results from commonly used general benchmarks and multimedia programs show that average cache miss ratio have been decreased by 10.5% for the block address lookup scheme(BAL) compare to conventional dynamic filter scheme(2-bitSC).

• Journal of KIISE:Databases
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• v.34 no.5
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• pp.448-464
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• 2007

Location-Based Services (LBSs) provide results to queries according to the location of the client issuing the query. In LBS, techniques such as caching and prefetching are effective approaches to reducing the data transmission from a server and query response time. However, they can lead to cache inefficiency and network overload due to the client's mobility and query pattern. To solve these drawbacks, we propose a semantic prefetching (SP) scheme using prefetching segment concept and improved cache replacement policies. When a mobile client enters a new service area, called semantic prefetching area, proposed scheme fetches the necessary semantic information from the server in advance. The mobile client maintains the information in its own cache for query processing of location-dependent data (LDD) in mobile computing environment. The performance of the proposed scheme is investigated in relation to various environmental variables, such as the mobility and query pattern of user, the distributions of LDDs and applied cache replacement strategies. Simulation results show that the proposed scheme is more efficient than the well-known existing scheme for range query and nearest neighbor query. In addition, applying the two queries dynamically to query processing improves the performance of the proposed scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.99-107
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• 2002

Broadcast disks are suited for disseminating information to a large number of clients in mobile computing environments. In broadcast disks, the server continuously and repeatedly broadcasts all data items in the database to clients without specific requests. The clients monitor the broadcast channel and retrieve data items as they arrive on the broadcast channel. The broadcast channel then becomes a disk from which clients can retrieve data items. In this paper, we propose a cache conscious concurrency control ($C^4$) scheme to preserve the consistency of client transactions, when the values of broadcast data items are updated at the server. $C^4$ scheme is novel in the sense that it can reduce the response time of client transactions with minimal control information to be broadcast from the server. This is achieved by the judicious caching strategy of the clients.