• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.103-105
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• 2004

본 논문에서는 프로세스 모니터링 기법에 기반한 DVS 시스템을 제안한다. 이상적인 DVS 시스템은 응용프로그램의 수정 없이 자동으로 수행되어야 하며 프로세스의 QoS를 고려해야 한다. 본 논문은 이를 위해 본 연구의 이전 논문에서 제시한 Kernel Control Path를 모니터링하여 주기적 프로세스의 QoS관련 정보를 추출할 수 있는 기법을 기반으로 DVS 시스템을 제안한다. 제안한 DVS 시스템은 리눅스 운영체제상에서 실제 구현하였으며 관련 연구와의 비교를 위해 관련연구도 구현하여 실험하였다. 이를 통해 제안한 DVS 시스템이 주기적 프로세스의 QoS를 보장하면서 전력소비를 최소화할 수 있음을 밝힌다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.93-99
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• 2008

Portable devices generally have limited energy sources, so there is a need to minimize the power consumption of processor using energy conservation methods. One of the most common energy conservation methods is dynamic voltage scaling (DVS). In this paper, we propose a new DVS algorithm which uses workload of application to determine frequency and voltage of processors. The posed DVS algorithm consists of DVS module in kernel and specified function in application. The DVS module monitors the processor utilization and changes frequency and voltage periodically. The other part monitors workload of application. With these two procedures, the processor can change the performance level to meet their deadline while consuming less energy. We implemented the proposed DVS algorithm on PXA270 processor with Linux 2.6 kernel.

• Journal of Computing Science and Engineering
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• v.4 no.3
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• pp.189-206
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• 2010

It is generally accepted that dynamic voltage scaling (DVS) is one of the most effective techniques of energy minimization for real-time applications in embedded system design. The effectiveness comes from the fact that the amount of energy consumption is quadractically proportional to the voltage applied to the processor. The penalty is the execution delay, which is linearly and inversely proportional to the voltage. According to the granularity of tasks to which voltage scaling is applied, the DVS problem is divided into two subproblems: inter-task DVS problem, in which the determination of the voltage is carried out on a task-by-task basis and the voltage assigned to the task is unchanged during the whole execution of the task, and intra-task DVS problem, in which the operating voltage of a task is dynamically adjusted according to the execution behavior to reflect the changes of the required number of cycles to finish the task before the deadline. Frequent voltage transitions may cause an adverse effect on energy minimization due to the increase of the overhead of transition time and energy. In addition, DVS needs to be carefully applied so that the dynamically varying chip temperature should not exceed a certain threshold because a drastic increase of chip temperature is highly likely to cause system function failure. This paper reviews representative works on the theoretical solutions to DVS problems regarding inter-task DVS, intra-task DVS, voltage transition, and thermal-aware DVS.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.115.2-116
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• 2003

Complete genomic nucleotide sequence of Daphe virus S (DVS), a member of the genus Carlavirus, causing leaf distortion and chlorotic spot disease symptoms in daphne plants, has been determined in this study. The genome of DVS contained six open reading fames coding for long viral replicase, triple gene block, 36 kDa viral coat protein (CP) and 12 kDa from the 5' to 3' ends, which is a typical genome structure of carlaviruses. Two Korean isolates of DVS isolates were 98.1％ and 93.6％ amino acid identical in the CP and 12kDa, respectively. The CP gene of DVS shares 25.2-55.2％ and 42.9-56.1％ similarities with that of 19 other carlaviruses at the amino acid and nucleotide levels, respectively. The 3'-proximal 12 kDa gene of DVS shares 20.2-57.8％ amino acid identities with that of 18 other members of the genus. The 3' noncoding region of DVS consists of 73 nucleotides with long excluding poly A tract, and shares 69.1-77.1％ identities to the known carlaviruses. In the phylogenetic analyses of the two proteins, DVS was closely related to Helenium virus S and Chrysanthemum virus B. This is the first complete sequence information for the DVS, and further confirms the classification of DVS as a distinct species of the genus Carlavirus.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.2
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• pp.95-103
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• 2007

Dynamic voltage scaling (DVS) is a well-known and effective power management technique. While there has been research on slack distribution, voltage allocation and other aspects of DVS, its effects on non-voltage-scalable devices has hardly been considered. A DC-DC converter plays an important role in voltage generation and regulation in most embedded systems, and is an essential component in DVS-enabled systems that scale supply voltage dynamically. We introduce a power consumption model of DC-DC converters and analyze the energy consumption of the system including the DC-DC converter. We propose an energy-optimal off-line DVS scheduling algorithm for systems with DC-DC converters, and show experimentally that our algorithm outperforms existing DVS algorithms in terms of energy consumption.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.428-430
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• 2006

This paper proposes a new means of performance optimization for multimedia algorithm utilizing the Microscopic DVS (Dynamic Voltage Scaling). The Microscopic DVS technique controls the operating frequency and the supply voltage levels dynamically according to the processing requirement for each frame of multimedia data. The huffman decoding algorithm of MPEG-2 AAC audio decoder is optimized to maximize the power saving efficiency of Microscopic DVS technique. The experimental results show the reduction of computational complexity by more than 30% and the reduction of power consumption by more than 17% compared with those of the conventionally fast method.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.12
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• pp.544-546
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• 2006

This paper proposes a new means of performance optimization for multimedia algorithm utilizing the Microscopic DVS (Dynamic Voltage Scaling). The Microscopic DVS technique controls the operating frequency and the supply voltage levels dynamically according to the processing requirement for each frame of multimedia data. The huffman decoding algorithm of MPEG-2 AAC audio decoder is optimized to maximize the power saving efficiency of Microscopic DVS technique. The experimental results show the reduction of computational complexity by more than 30% and the reduction of power consumption by more than 17% compared with those of the conventionally fast method.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.12
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• pp.736-748
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• 2003

Dynamic voltage scaling(DVS), which adjusts the clock speed and supply voltage dynamically, is an effective technique in reducing the energy consumption of embedded real-time systems. The energy efficiency of a DVS algorithm largely depends on the performance of the slack estimation method used in it. In this paper, we propose novel DVS algorithms for periodic hard real-time tasks based on an improved slack estimation algorithm. Unlike the existing techniques, the proposed method can be applied to most priority-driven scheduling policies. Especially, we apply the proposed slack estimation method to EDF and RM scheduling policies. The experimental results show that the DVS algorithms using the proposed slack estimation method reduce the energy consumption by 20∼40 % over the existing DVS algorithms.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1380-1390
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• 1999

To assess the food intake and diet quality of preschool children in Pusan, dietary survey was conducted with 176 subjects using 24hr recall method. Diet quality was assessed by food group pattern, dietary diversity score(DDS), dietary variety score(DVS), and dietary frequency score(DFS). The total number of food items consumed was 307. The foods consumed most frequently were rice, Korean cabbage kimchi, milk and green onion. When investigating the consumption pattern of major six food groups, 38.1% of subjects consumed all six groups. Food group was missed in order of fruit(41.5%), sweet(19.9%), dairy(16.5), vegetable(4.5%) and meat(1.7%). The mean values of DDS, DVS, and DFS were 5.16, 13.82, and 16.07 re spectively. Persons who had higher DDSs also had higher DVSs(p<0.001). DDS, DVS and DFS correlated positively with NAR(nutrient adequacy ratio) and MAR(mean adequacy ratio) significantly. Associations between the NAR of most nutrients and MAR with DVS and DFS were higher than those between the NAR of most nutrients and MAR with DDS. People with DDS of above 6 or DVS of above 16 or DFS of above 21 met two thirds of recommended dietary allowance for nutrients. Based on the result of the food group intake, the food intake of subjects was not adequate, especially the fruit and dairy groups. When assessing the dietary quality of subjects using DDS, DVS and DFS, many people appeared not to have a desirable food intake.

• Culinary science and hospitality research
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• v.13 no.2
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• pp.81-97
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• 2007

To assess the food intake and diet quality by the interrelationship of DDS and DVS of high school girls, this dietary survey was conducted with 253 subjects living in Iksan and Seoul areas using a 24-hour recall method. The average amount of total food intake was 1,133.2 g, with 79.9% of food intake being supplied by vegetable food and 20.1% by animal food and higher in Seoul area. The food consumed most frequently was rice, green onion, garlic, soy sauce, sesame oil, onion, and Kimchi. The food consumed in the largest amounts were rice(303.3 g), milk(62.2 g), and Kimchi(53.4 g). Diet quality was assessed by food group pattern, dietary diversity score(DDS), and dietary variety score(DVS). When investigating the consumption pattern of major five food groups(grain, meat, dairy, fruit, vegetable groups), nobody consumed all five food groups in each meal. The groups most frequently missing were fruits and dairy products. The average number of food consumed per day was 12.1(DVS) and Iksan area scored lower(11.7) on DVS than Seoul area(12.6). The higher DDS and DVS of subjects were, the more MAR and NAR of energy, calcium, vitamin A and C increased. The number of major food groups(DDS)(p<0.01, P<0.05) and that of food items (DVS)(p<0.01) correlated positively NAR(nutrient adequacy ratio) and MAR (mean adequacy ratio) significantly.