• The Korean Nurse
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• v.3 no.1 s.9
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• pp.59-68
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• 1964

• Journal of IKEEE
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• v.12 no.3
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• pp.138-143
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• 2008

In this study, we propose that the structures of spiral inductors have the environment advantage utilizing direct-write and LAM(Laser Ablation of Microparticles) processes without process step of lithography and etching etc. of existing semiconductor process. The structures of inductors have Si thickness of 540${\mu}m$, $SiO_2$ thickness of 3${\mu}m$. The width of Cu coils and the space between segments have 30${\mu}m$, respectively, using for direct-write and LAM processes. The performance of spiral planar inductors was simulated to frequency characteristics for inductance, quality-factor, SRF(Self- Resonance Frequency) using HFSS. The inductors without underpass and via have inductance of 1.11nH over the frequency range of 300 to 800 MHz, quality-factor of maximum 38 at 5 GHz, SRF of 18 GHz. Otherwise, inductors with underpass and via have inductance of 1.12nH over the frequency range of 300 to 800 MHz, quality-factor of maximum 35 at 5 GHz, SRF of 16 GHz.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.11
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• pp.95-100
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• 2007

A low power PRAM using a power-dependant data inversion (PDI) scheme is proposed. The PRAM consumes large write power because large write currents are required during long time. Also, the power consumptions for storing #1# and #0# are different. The PDI circuit compares the power consumptions to store the original data and its inverted data, and then it stores the less power consuming data. Although the PDI scheme needs an additional inversion bit per data, the maximum and average powers of the PDI can be under 50% and 37.5% of the conventional write scheme, respectively. The average power for storing 8bit data is under 41%, due to the inversion bit. The 1K-bit PRAM chip with 128$\times$8bits was implemented with a 0.8${\mu}m$ CMOS technology with a 0.5${\mu}m$ GST cell.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.15-20
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• 2016

Write amplification is a critical factor that limits the stable performance of flash-based storage systems. To reduce write amplification, this paper presents a new technique that cooperatively manages data in flash storage and nonvolatile memory (NVM). Our scheme basically considers NVM as the cache of flash storage, but allows the original data in flash storage to be invalidated if there is a cached copy in NVM, which can temporarily serve as the original data. This scheme eliminates the copy-out operation for a substantial number of cached data, thereby enhancing garbage collection efficiency. Experimental results show that the proposed scheme reduces the copy-out overhead of garbage collection by 51.4% and decreases the standard deviation of response time by 35.4% on average.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4997-5006
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• 2010

A flash-memory-based SSDs(Solid State Disks) are one of the best media to support portable and desktop computers' storage devices. Their features include non-volatility, low power consumption, and fast access time for read operations, which are sufficient to present flash memories as major database storage components for desktop and server computers. However, we need to improve traditional storage management schemes based on HDD(Hard Disk Drive) and RAID(Redundant array of independent disks) due to the relatively slow or freezing characteristics of write operations of SSDs, as compared to fast read operations. In order to achieve this goal, we propose a new storage management scheme called Hetero-Mirroring based on traditional HDD mirroring scheme. Hetero-Mirroring-based scheme improves RAID-1 operation performance by balancing write-workloads and delaying write operations to avoid SSD freezing. Our test results show that our scheme significantly reduces the write operation overheads and freezing overheads, and improves the performance of traditional SSD-RAID-1 scheme by 18 percent, and the response time of the scheme by 38 percent.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.39-46
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• 2013

If a file system is damaged because of the unusual system close, the system performs the consistency test using fsch and it takes long time. Especially, if it is a big file system, it will take a lot of time. The journaling file system that uses journaling technique, can reduce the restoring time because it uses meta data and it may increase the chance of restoration when restoring. The goal of this paper compared performance evaluation journaling file systems focused on the reading and writing using Iozone tool which is the kernel based benchmarking tool in linux operating system. In this paper, Ex4 which is the current basic Linux file system. is 1.28x faster than XFS file system in terms of file read performance and 1.22x faster than Ext3 file system in terms of file write performance.

• KIISE Transactions on Computing Practices
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• v.21 no.12
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• pp.786-791
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• 2015

The environment of Internet of Things (IoT) wherein various devices are connected through the Internet with value-added network functions, is currently a subject of active study. Accordingly, the existing computing environment based on desktop or mobile systems is being expanded into a computing environment of more diverse devices. Because the response of program launching is important in terms of User Experience (UX) in IoT environments, the technology for guaranteeing rapid response of program launching in IoT devices is getting the focus of much current research. In this paper we analyze the Zygote technique, which is being used for faster program execution in Android systems, and, based on our results, we propose an address space maintaining scheme for the rapid launching of programs for use in Linux-based systems. Our scheme utilizes the Copy on Write (CoW) technique in Linux systems as well as the Zygote technique of Android systems. In order to evaluate the proposed scheme, we implemented our scheme on Linux systems and performed several experiments. The experimental results show that the proposed scheme shortens the launching time up to 99%, compared to the existing technique.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.807-811
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• 2007

In this paper, we introduce an application virtualization method that could be supported without changing and modifying any resources and execution environment on host system, using non-installable portable software format that could be executed by one-click on any host without installing process. For the purpose of designing and implementing an application virtualization method, we construct virtual supporting system that includes virtual file system and virtual registry hive on kernel level of Windows operating system. Also, when users execute portable software on any hosts to provide consistency on using portable software, we describe method of processing information of appending and modifying files and registry datum on virtual file system and virtual registry hive through Copy-on-Write scheme.

• Journal of Korean Elementary Science Education
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• v.33 no.4
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• pp.724-735
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• 2014

The purpose of this study was to confirm correlation between elementary school students' VARK Learning styles test and Scientific Communication Skills through VARK questionnaire (version 7.3) for Youngers and Scientific Communication Skills Test. The subjects were 99 in 6th grade students of an elementary school located in Gyeonggi-do, Korea. The results of this study were as follows: 64% of the students had multiple learning styles, but only 36% of the students preferred a single mode of information presentation. Among students had a single mode preference, the aural ("A") was the highest unimodal preference. Among "V(visual)" mode, "A" mode, "R(read/write)" mode, and "K(kinesthetic)" mode, "A" mode was the commonest learning mode which students had. In Scientific Communication Skills Test, students' overall average was 26.19p [scientific explanation type (11.85p), scientific insistence type (14.34p)]. Girls' scores were higher than boys in scientific explanation type, but not in scientific insistence type. The scores by communication forms were Text (5.67p), Number (6.87p), Table (6.15p), and Picture (7.49p). Girls' scores were higher than boys in Text and Picture forms but not in Number and Table forms. In result of correlation analysis (Spearman's rho) between VARK Learning Styles and the types & forms of Scientific Communication Skills, there were common correlation in "Read/write (R) learning style-Scientific insistence type", "Read/write (R) learning style-Grounds of Scientific insistence", "Read/write (R) learning style-Description of Scientific explanation", and "R learning style-Text form".

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.634-641
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• 2006

Flash memory has many advantages like non-volatility and fast I/O speed, but it has also disadvantages such as not-in-place-update data and asymmetric read/write/erase speed. For the performance of flash memory storage, it is essential for the buffer replacement algorithms to reduce the number of write operations that also affects the number of erase operations. A new buffer replacement algorithm is proposed in this paper, that delays the writes of not-cold-dirty pages in the buffer cache of flash storage. We show that this algorithm effectively decreases the number of write operations and erase operations without much degradation of hit ratio. As a result overall performance of flash I/O speed is improved.