• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.117-123
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• 2013

In the recent cloud storage environment, the amount of SSD (Solid-State Drive) replacing with the traditional hard disk drive is increasing. Management of SSD for its space efficiency has become important since SSD provides fast IO performance due to no mechanical movement whereas it has wearable characteristics and does not provide in place update. In order to manage space efficiency of SSD, data de-duplication technique is frequently used. However, this technique occurs much overhead because it consists of data chunking, hasing and hash matching operations. In this paper, we propose new data de-duplication method using PRAM cache. The proposed method uses hierarchical hash tables and LRU(Least Recently Used) for data replacement in PRAM. First hash table in DRAM is used to store hash values of data cached in the PRAM and second hash table in PRAM is used to store hash values of data in SSD storage. The method also enhance data reliability against power failure by maintaining backup of first hash table into PRAM. Experimental results show that average writing frequency and operation time of the proposed method are 44.2% and 38.8% less than those of existing data de-depulication method, respectively, when three workloads are used.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.5
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• pp.101-106
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• 2020

Since computer became available, much effort has been made to achieve information security. Even though memory protection defense mechanisms were studied the most among of them, the problems of existing memory protection defense mechanisms were found due to improved performance of computer and new defense mechanisms were needed due to the advent of the side-channel attacks. In this paper, we propose JMP+RAND that embedding random values of 5 to 8 bytes per page to defend against memory sharing based side-channel attacks and bridging the gap of existing memory protection defense mechanism. Unlike the defense mechanism of the existing side-channel attacks, JMP+RAND uses static binary rewriting and continuous jmp instruction and random values to defend against the side-channel attacks in advance. We numerically calculated the time it takes for a memory sharing-based side-channel attack to binary adopted JMP+RAND technique and verified that the attacks are impossible in a realistic time. Modern architectures have very low overhead for JMP+RAND because of the very fast and accurate branching of jmp instruction using branch prediction. Since random value can be embedded only in specific programs using JMP+RAND, it is expected to be highly efficient when used with memory deduplication technique, especially in a cloud computing environment.

• Therapeutic Science for Rehabilitation
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• v.11 no.2
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• pp.7-24
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• 2022

Objective : To develop standardized assessment tools that evaluate the multi-aspect lifestyles of children and adolescents, we aimed to systematically analyze lifestyle assessment tools and lifestyle component-specific assessment tools. Methods : The study period was 2001-2020, with search engines using CINANL, NDSL, PubMed, and RISS. Search key words used 'lifestyle assessment' OR 'lifestyle profile' OR 'lifestyle test', 'physical activity assessment' OR 'physical activity participation profile', 'nutrition assessment' OR 'nutrition profile', 'activity participation assessment' OR 'activity participation profile'. Results : A total of 24 evaluation tools were selected after 5,883 studies reviewed the title, abstract, and full text after deduplication. The detailed results resulted in five lifestyle assessment tools, seven physical activity assessment tools, nine nutrition assessment tools, and three activity participation assessment tools. Conclusion : For the lifestyle assessment tools for children and adolescents, the component items, measurement methods, and age of assessment of each item were analyzed. It is hoped that this will be used as a basis for the development of standardized assessment tools to assess the multi-aspect lifestyles of children and adolescents in the future.