• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.672-674
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• 1998

Java virtual machine has the garbage collector that automate memory management. Mark-compact algorithm is one of the garbage collection algorithm that operating in 2 phases, marking and sweeping. One is Marking is marking live objects reachable from root object set. Sweeping is sweeping unmarked object from memory(return to free memory pool). This algorithm is easy to implement but cause a memory fragmentation. So compacting memory, before memory defragmentation become serious. When compacting memory, all other processes are suspended. It is critical for embedded system that must guarantee real-time processing. This paper introduce enhanced mark-compact garbage collection algorithm. Grouping the objects by their size that minimize memory fragmentation. Then apply smart algorithm to the grouped objects when allocating objects and compacting memory.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.6
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• pp.57-62
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• 2022

Recently, fast storage media such as phage-change memory (PCM) emerge, and memory management policies for slow disk storage need to be revisited. In this paper, we propose a new page replacement policy that makes use of PCM as a swap device of virtual memory systems. The proposed policy aims at reducing write traffic to the swap device as well as reducing the number of page faults pursued by traditional page replacement policies. This is because a write operation in PCM is slow and PCM has limited write endurances. Specifically, the proposed policy focuses on the reduction of page faults when the memory load of the system is high, but it aims at reducing write traffic to storage when free memory space is sufficient. Simulation experiments with various memory reference traces show that the proposed policy reduces write traffic to PCM without performance degradations.

• Journal of Multimedia Information System
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• v.6 no.1
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• pp.7-14
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• 2019

This work presents a virtual prototyping design approach for an area-based image stitching hardware. The virtual hardware obtained from virtual prototyping is equivalent to the conceptual algorithm, yet the conceptual blocks are linked to the actual circuit components including the memory, logic gates, and arithmetic units. Through the proposed method, the overall structure, size, and computation speed of the actual hardware can be estimated in the early design stage. As a result, the optimized virtual hardware facilitates the hardware implementation by eliminating trail design and redundant simulation steps to optimize the hardware performance. In order to verify the feasibility of the proposed method, the virtual hardware of an image stitching platform has been realized, where it required 10,522,368 clock cycles to stitch two $1280{\times}1024$ sized images. Furthermore, with a clock frequency of 250MHz, the estimated computation time of the proposed virtual hardware is 0.877sec, which is 10x faster than the software-based image stitch platform using MATLAB.

• Proceedings of the KAIS Fall Conference
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• 2010.05a
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• pp.523-526
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• 2010

본 논문에서는 우리 옛 조선의 한양 모습을 경복궁을 중심으로 가상현실을 이용하여 복원 하였다. 복원에 있어 단원 분할 및 Resource Manager Discard Bytes channel의 가상현실 방법을 채택하여 memory 및 vedio memory 점유율을 낮춰 가상현실 실행 속도와 그래픽 효과의 퀄리티를 높이는데에 그 목적이 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.435-437
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• 2000

본 논문은 IJG JPEG 시스템에서 사용된 효율적인 메모리 관리 방법에 대해 소개한다. IJG JPEG 시스템의 메모리 관리 모듈은 여러 시스템에 독립적일 수 있도록 다양한 종류의 메모리 관리 모듈을 두고 있다. 각 메모리 관리 모듈은 메모리 객체를 small, large, virtual의 3가지로 구분하여 할당/해제하는데, 객체 단위로 할당/해제하지 않고

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.6
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• pp.476-487
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• 2009

The virtual memory system in 4.4 BSD operating systems exploits a clustering scheme to reduce disk I/Os in paging out (or flushing) modified pages that are intended to be replaced in order to make free rooms in memory. Upon the page out of a victim page, the scheme stores a cluster (or group) of modified pages contiguous with the victim in the virtual address space to swap disk at a single disk write. However, it fails to find large clusters of contiguous pages if applications change pages not adjacent with each other in the virtual address space. To address the problem, we propose a new clustering scheme called Multiple-Object Clustering (MOC), which together stores multiple clusters in the virtual address space at a single disk write instead of paging out the clusters to swap space at separate disk I/Os. This multiple-cluster transfer allows the virtual memory system to significantly decrease disk writes, thus improving the page-out performance. Our experiments in the FreeBSD 6.2 show that MOC improves the execution times of realistic benchmarks such as NS2, Scimark2 SOR, and nbench LU over the traditional clustering scheme ranging from 9 to 45%.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.335-344
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• 2014

In this paper we analysis for in out signal by previous study and implement virtual master that generate CGH processor signals. Also, we propose memory address mapping. By constructing the system model of our method and by analyzing the latencies according to the memory access methods in a system including our model and several other models, the low-latency memory access method has been obtained. The proposed method is reduce number of activation in DRAM.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.12
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• pp.4776-4798
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• 2015

The location selection of virtual machines in distributed cloud is difficult because of the physical resource distribution, allocation of multi-dimensional resources, and resource unit cost. In this study, we propose a multi-object virtual machine location selection algorithm (MOVMLSA) based on group information, doubly linked list structure and genetic algorithm. On the basis of the collaboration of multi-dimensional resources, a fitness function is designed using fuzzy logic control parameters, which can be used to optimize search space solutions. In the location selection process, an orderly information code based on group and resource information can be generated by adopting the memory mechanism of biological immune systems. This approach, along with the dominant elite strategy, enables the updating of the population. The tournament selection method is used to optimize the operator mechanisms of the single-point crossover and X-point mutation during the population selection. Such a method can be used to obtain an optimal solution for the rapid location selection of virtual machines. Experimental results show that the proposed algorithm is effective in reducing the number of used physical machines and in improving the resource utilization of physical machines. The algorithm improves the utilization degree of multi-dimensional resource synergy and reduces the comprehensive unit cost of resources.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.2914-2935
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• 2016

With the increasing popularization of cloud computing, how to reduce physical energy consumption and increase resource utilization while maintaining system performance has become a research hotspot of virtual machine deployment in cloud platform. Although some related researches have been reported to solve this problem, most of them used the traditional heuristic algorithm based on greedy algorithm and only considered effect of single-dimensional resource (CPU or Memory) on energy consumption. With considerations to multi-dimensional resource utilization, this paper analyzed impact of multi-dimensional resources on energy consumption of cloud computation. A multi-dimensional resource constraint that could maintain normal system operation was proposed. Later, a novel virtual machine deployment method (NVMDM) based on improved particle swarm optimization (IPSO) and Euclidean distance was put forward. It deals with problems like how to generate the initial particle swarm through the improved first-fit algorithm based on resource constraint (IFFABRC), how to define measure standard of credibility of individual and global optimal solutions of particles by combining with Bayesian transform, and how to define fitness function of particle swarm according to the multi-dimensional resource constraint relationship. The proposed NVMDM was proved superior to existing heuristic algorithm in developing performances of physical machines. It could improve utilization of CPU, memory, disk and bandwidth effectively and control task execution time of users within the range of resource constraint.

• Journal of the Korea Society of Computer and Information
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• v.18 no.2
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• pp.41-47
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• 2013

In this paper, for this open system-based virtual resource monitoring system was designed. Virtual resources, CPU, memory, disk, network, each subdivided into parts, each modular implementation. Implementation results in real time CPU, memory, disk, network information, confirmed the results of monitoring. System designed to implement the Windows, Linux, Xen was used for the operating system, implementation language, C++ was used, the structure of the system, such as the ability to upgrade and add scalability and modularity by taking into account the features available in cloud computing environments applicable to cloud computing, virtual resource monitoring system has been implemented.