• Journal of KIISE:Information Networking
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• v.27 no.2
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• pp.138-148
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• 2000

In the mobile computing environment, in order to make copies of important files available when being disconnected the mobile host(client) must store them in its local cache while the connection is maintained. In this paper, we propose the prefetching mechanism for the client to save files which may be accessed in the near future. Our mechanism utilizes analyzer, prefetch-list producer, and prefetch manager. The analyzer records file access patterns of the user in a FAP(File Access Patterns) profile. Using the profile, the prefetch-list producer creates the prefetch-list. The prefetch manager requests a file server to return this list. We set the parameter TRP(Threshold of Reference Probability) to ensure that only reasonably related files can be prefetched. The prefetch-list producer adds the files to a prefetch-list if their reference probability is greater than the TRP. We also use the parameter TACP(Threshold of Access Counter Probability) to reduce the hoarding size required to store a prefetch-list. Finally, we measure the metrics such as the cache hit ratio, the number of files referenced by the client after disconnection and the hoarding size. The simulation results show that the performance of our mechanism is superior to that of the LRU caching mechanism. Our results also show that prefetching with the TACP can reduce the hoard size while maintaining similar performance of prefetching without TACP.

• The Journal of the Korea Contents Association
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• v.10 no.2
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• pp.330-341
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• 2010

The purpose of this study is to have comparative analysis on the differences between metropolis and provincial city's electronic security system users' security needs satisfaction and life satisfaction. This study sampled total 400 users with using purposeful sampling after selecting specific metropolis and provincial cities as population. It was conducted on 4 realms-bank, jewelry store, convenience store and communication industry- with two times. First one was on June, 2008, it was conducted in Seoul, 5 areas divided based on Hangang, which are Gang-dong, Gang-seo, Gang-nam, Gang-buk, and civic center. We sampled 40 electronic security system users of each area which are 200 in sum. Second one was on January, 2009, with users in Cheonan and Asan, 200 was sampled in the same way with metropolis; 100 users of each city. The reliability of the questionnaire showed Cronbach's ${\alpha}$ value over .812. The results are as follows. First, there showed difference on physical security needs satisfaction of electronic security system users with the size of city. In other word, users in metropolis have higher environmental, psychological, and informational security needs satisfaction than users in provincial city. Second, there is also difference in life satisfaction. Namely, users in metropolis have higher security needs satisfaction than users in provincial city. Third, security needs satisfaction of electronic security system users by city size effects life satisfaction. That is, in case of users in metropolis, the more physical, environmental, and informational security needs satisfaction it shows, the more life satisfaction it showed.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.5 s.142
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• pp.637-648
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• 2005

The purpose of this study was to investigate the differences among internet and TV home-shopping perceived risk segments in regard to clothing shopping orientations and purchase intention. The subjects used for the study were 290 female consumers aged from 20 to 40 living in Seoul. The study used factor analysis, cluster analysis, ANOVA, Duncan test, and $\chi^2-test$. The results showed that the Internet and TV home-shopping perceived risks consisted of 9 factors: Products uncertainty risk, Internet shopping mall trust risk, account-related risk, delivery risk, social risk, size risk, exchange/return risk, TV watching-related risk, and price risk. The cluster analysis showed that there were five groups segmented: Size risk/TV watching risk group, Social risk/Internet trust risk group, Return risk/TV watching low-risk group, Delivery risk/product trust group, and Product risk group. The clothing shopping orientations were classified by 5 factors: Planned shopping, pleasure shopping, sales/fashion oriented shopping, time saving shopping, and credit card preference/in-store oriented shopping. The results showed that the five segmented perceived risk groups differed in regard to clothing shopping orientations, purchase intention, and demographics. Further group differences and implications of the results were discussed.

• Journal of the Korean Society of Costume
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• v.52 no.5
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• pp.15-30
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• 2002

The purposes of this study were to identify the Chinese university students' clothing attitudes and purchasing behavior according to their lifestyle. Questionnaires developed by researcher were distributed and collected from 540 Chinese university students from Mar. 5 to Mar. 20, 2001. Means, frequencies, and percentages were calculated. Factor analysis, cluster analysis. one-way ANOVA, and Chi-square test were used for data analysis. And Duncan's multiple range test was followed. The factors of lifestyle were consumption, self-confidence, economy, accomplishment. sociability. fashionability, individuality, and conservation. Chinese university students were segmented into 4 groups of the modern sociable, the passive stagnated, the positive progresive, and the traditional conservative. The group size of the modem sociable was the smallest, and the traditional conservative was the largest. Chinese university students considered sexual attractiveness of clothing most important. Psychological dependence and ostentation of clothing were next important in a decending order. The passive stagnated considered conformity of clothing most important and showed the opposite tendency of the modern socialable. The positive progressive considered all aspects of clothing attitudes important, and showed the opposite tendency of the traditional conservative. Chinese university students utilized direct fashion information sources, and patronized medium or small size department store or traditional market.

• Journal of the Korea Computer Industry Society
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• v.2 no.2
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• pp.211-218
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• 2001

In this paper, we propose the structure of utilizing the memory map, which is using not conventional DRAM but SDRAM, for the hardware implementation of frame memory interface module to the video encoder. As reducing the size of memory map and interface buffer within the same bus, the hardware complexity is improved and the hardware size is minimized as simplifying the interface logic. The conventional system is wasted access time, because of accessing randomly stored data in order to store and output the memories in macro-block unit. therefore the method, which is proposed in this paper, can be effectively reducing the access time of memory, because of the data is stored and processed by line unit.

• Journal of the Korean Home Economics Association
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• v.43 no.1 s.203
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• pp.167-176
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• 2005

This study was intended to investigate the wearing conditions of shirts, and examine the preferred subjective sensation for shirt fabrics. A questionnaire survey was conducted on 469 university students (male students $45.3\%$, female students $54.7\%$) in the Cheongju area, Korea. Frequency, descriptive analysis, $\x^2$ and t-tests were used for data analysis. The results were as follows: Regardless of gender, most owned 4 shirts in the autumn, which were each worn once or twice week. Generally, patterned shirts were less favored than those with solid colors, regardless of gender, but the color of the shirts differed slightly according to gender. Most students gathered items from those displayed in the store as their source of information on shirts, and tended to purchase items worth $30,000\~50,000$ won at franchised stores with friends of the same gender. They almost always looked carefully at the size and brand, but the care label and fiber content were rather neglected during the purchase. While purchasing their shirts, the following elements were considered, in this order of importance: size; color; fitness; comfort; price; tactile sensation. Light, dense, soft, warm, wrinkle-free, dry and strong sensation of the shirt fabrics were the strongest preferences for a purchase. There were partially significant gender differences in the subjective sensation of shirt fabrics.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.1
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• pp.1-8
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• 2018

A problem exists in the conventional transportation cart applications, in which an external power supply with mechanical contact connection (bus bar connection) is required to drive the motor. Therefore, continuous effort for maintenance is required, aside from the expensive bus bar connector. To solve this problem, a self-electricity-generated transportation cart system without bus bar has recently been introduced. In this system, a battery needs to store the power of the generated wheel, and a boost converter, which converts the low battery voltage to high bus voltage to drive the motor inverter, is necessary. However, since the instantaneous large current required for starting the motor is supplied from the battery, a battery with large size and volume should be adopted to withstand this large current. In this study, a boost converter that can supply a large instantaneous current by using super Capacitor string is proposed. The proposed converter can be realized with a small size and volume compared with the conventional battery-fed boost converter. Operational principles, analysis, and design of the proposed converter are presented, and experimental results are provided to validate the proposed converter.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.9
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• pp.536-542
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• 2004

An architecture of direct digital frequency synthesizers (DDFS) is studied in this paper The Direct digital frequency synthesizers (DDFS) provide fast frequency switching with high spectral purity and are widely used in modern spread spectrum wireless communication systems. ROM-based DDFS uses a ROM lookup table to store the amplitude of a sine wave. In this paper, we suggest three new techniques to reduce the ROM size. One new technique uses more number of hierarchical levels in ROM structures. Another techniques use simple interpolation techniques combined with hierarchical ROM structures. A 12 bit sine wave is generated by using these techniques. Experimental results show that the new proposed techniques can reduce the required ROM size by up to 24%, when compared to that of a resent method[1].

• Korean Journal of Human Ecology
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• v.9 no.4
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• pp.41-53
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• 2006

The purpose of this study was to compare the characteristics of underwear consumer's underwear purchasing behavior through survey. 630 questionnaires were distributed in Seoul and Chonju and 618 with usable data were analyzed frequency and factor analyses, t-test etc. using SPSSWIN 10.0. program. The results were summarized as follows : Most male consumers buy underwears at discount stores whereas most female consumers at chain store. Throughout all four seasons, more male and female consumers do not wear heat-retaining underwears. Most male and female consumers do not have function-fiber underwears nor functional-finishing and natural-dyeing-treated underwears. Most consumers are not satisfied with these underwears. The most important criteria for most male consumers to choose underwears are comfort levels while in action, the sense of touch, comfort levels while wearing them while not in action, pleasance levels; whereas for females are comfort levels while in action, and comfort levels while wearing them while not in action. Male consumers prefer a little bigger-than-their-bodies size, dry and soft fabrics, plain white color; whereas female consumers prefer a little tight size, dry and soft fabrics and plain beige color, Most consumers want to buy functional-fiber underwears made of yellow- soil-and-charcoal-dyeing fabrics which has jade.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.2
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• pp.123-130
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• 2013

As size of genomic data is increasing rapidly, the needs for high-performance computing system to process and store genomic data is also increasing. In this paper, we captured I/O trace of a system which analyzed 500 million sequence reads data in Genome analysis pipeline for 86 hours. The workload created 630 file with size of 1031.7 Gbyte and deleted 535 file with size of 91.4 GByte. What is interesting in this workload is that 80% of all accesses are from only two files among 654 files in the system. Size of read and write request in the workload was larger than 512 KByte and 1 Mbyte, respectively. Majority of read write operations show random and sequential patterns, respectively. Throughput and bandwidth observed in each processing phase was different from each other.