• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.407-409
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• 2006

Geochemical analyses carried out on samples collected from cores on and near the southern smit of Hydrate Ridge have advanced understanding by providing a clear contrast of the two major modes of marine gas hydrate occurrence. High concentrations (15%-40% of pore space) of gas hydrate occurring at shallow depths (0-40 mbsf) on and near the southern summit are fed by gas migrating from depths of as much as 2km within the accretionary prism. This gas carries a characteristic minor component of C2-C5 thermogenic hydrocarbons that enable tracing of migration pathways and may stabilize the occurrence of some structure II gas hydrate. A structure II wet gas hydrate that is stable to greater depths and temperatures than structure I methane hydrate may account for the deeper, faint second bottom simulating reflection (BSR2) that occurs on the seaward side of the ridge. The wet gas is migrating In an ash/turbidite layer that intersects the base of gas hydrate stability on the seaward side of and directly beneath the southern summit of Hydrate Ridge. The high gas saturation (>65%) of the pore space within this layer could create a two-phase (gas + solid) system that would enable free gas to move vertically upward through the gas hydrate stability zone. Away from the summit of the ridge there is no apparent influx of the gas seeping from depth and sediments are characterized by the normal sequence of early diagenetic processes involving anaerobic oxidation of sedimentary organic matter, initially linked to the reduction of sulfate and later continued by means of carbonate reduction leading to the formation of microbial methane.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.310-315
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• 2008

Herein, we synthesized silica-coated chrome yellow particles having improved chemical resistance. The intermediate with a good dispersion stability was prepared and the chemical resistance of the final product was investigated. The effects of pH and temperature, as the main parameters influencing the formation of particles, the reduced particle size by homogenizer on the silica coating were investigated. The change in the particle morphology by temperature and pH was also studied. As the results, small and monodisperse particles were achieved at low pH and high temperature. Good silica coating was obtained when used reduced size of the particles by homogenizer. Furthermore, the sufficient silica coating by microencapsulation was obtained at 9~10 pH and the temperature above $90^{\circ}C$.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.123-127
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• 2016

Methanol fuel cells having advantages of relatively favorable reaction kinetics and higher energy density have attracted increasing interests as best alternative to hydrogen fuel cell because of H2 production, storage and distribution issues. While there have been extensive research works on developing key components such as electrocatalysts as well as their physicochemical properties in practical formic acid fuel cells, there have also been urgent requests for investigating which fuel sources will be more suitable for direct liquid fuel cells in future. In this mini-review, we highlight the overall interest and outlook of formic acid fuel cells in terms of electrocatalysts, fuel supply and crossover, water management, fuel cell efficiency and system integration in comparison with methanol fuel cells.

• Korean Journal of Community Nutrition
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• v.4 no.1
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• pp.46-56
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• 1999

A deep understanding of the dietary patterns and nutrient intake is important for assessment of possilbe nutritional risk and for establishing nutrition improvement strategies. This study was conducted toexamine the dietary characteristics of a nutritionally poor elderly group compared to the middle-and highly-nourished group. Elderly participant was recruited from local elderly centers in Suwon city in 1998. Trained dietitians interviewed 119 elderly(35 males, 84 females) aged 60 years and over for collecting dietary data(24-hour recall) and related variables. Male and female subjects were grouped into high, middle, and low according to the mean nutrient adequancy ratio(MAR) tertiles. An analysisof the percentage of RDA(Recommended Daily Allowances of Korea) for each of the 10 nutrients showed that the male low-MAR group consumed below the RDA in all kinds of nutrients, and the female low-MAR group consumed nutrients below the RDA except vitamin C. An evaluation of nutrient density by Index of Nutritonal Quality(INQ) also showed a similar tendency. Thus, the INQ level of the male low-MAR group was significantly lower than the middle-or high-MAR group, especially in protein, vitamin A, thiamin, riboflavin, and phosphorus(p<0.05). Moreover, INQ level of female low-MAR group was significantly lower than that of the high group(p<0.05) in all nutrients. The female low-MAR group's daily food intake were also lower than those of the high-MARgroup in gains, fish, fruits, oil and beverages. The energy distribution from carbohydrates, fats and proteins showed that the male low-MAR group had significantly higher carbohydrate and lower fat proportions compared to each gender high-MAR group, respectively. The male and female low-MAR group had low scores about eating all side dishes. These findings indicate that a moderate increase of the meat/egg/fishes intake was needed by the male low-MAR group for improving nutrition adequacy, and an overall increase of the food quantity and quality was desired for the female low-MAR group. These data could be used for planning a community elderly nutrition program and establishing strategies for tailored guidelines for the individuals.

• Journal of Nutrition and Health
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• v.41 no.4
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• pp.341-352
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• 2008

The number of school lunch-supported children who belong to low-income families has been rapidly increased in Korea. This study was aimed at evaluation of nutritional status of school lunch-supported elementary school children. One hundred school lunch-supported children and 119 non-supported children of fourth to sixth year class in 3 elementary schools in Gyeongbuk rural area were selected, and surveys were conducted twice, i.e., once during school term and once during summer vacation in 2006. Food consumption survey during school term was carried out through an interview by dieticians at school-lunch time using a 24-hour recall method, and the survey during summer vacation conducted by recording food intakes for three days by children. Nutrient intakes were calculated using CAN-Pro 3.0 program. School lunch-supported children showed higher rate of skipping breakfast and rather irregular meal time as compared to non-supported students. Eating alone was more frequent in school lunch-supported children than in nonsupported children. The average nutrient intakes and nutrient adequacy ratios were lower in supported children than in non-supported children. During term, percentages of nutrient intakes provided by school-lunch were higher in supported children than in non-supported children. Intakes of energy nutrients were within acceptable macronutrient distribution ranges, but proportion of carbohydrate intake increased during vacation. Analysis of patterns of food intakes based on major food groups (dairy, meat, grain, fruit, vegetable) indicated that meals during term were more balanced as compared to meals during vacation. In conclusion, food behaviors and nutrient intakes of school lunchsupported children were inferior to those of non-supported children during term and during summer vacation. They were provided with more nutrient intakes from school lunch during term as compared to non-supported children. Therefore, it is necessary not only to keep meal support program during vacation but also to provide a proper nutrition education as a part of school lunch program to improve nutritional status and food behaviors of school lunch-supported children.

• Journal of the Korea Computer Industry Society
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• v.6 no.3
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• pp.465-476
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• 2005

The wireless sensor network consists of a number of sensor nodes which have physical constraints. Each sensor node senses surrounding environments and sends the sensed information to Sink. In order to alleviate the inherent vulnerability in security of the wireless sensor nodes with the hardware constraints, the lightweight security protocol is needed and a variety of research is ongoing. In this paper, we propose a non-hierarchical sensor network and a security protocol that is suitable for monitoring man-made objects such as bridges. This paper, furthermore, explores a two-layer authentication, key distribution scheme which distributes the key and location of a sensor node in advance, and an effective security routing protocol which can take advantage of the Sleep and Awake state. This also results in the increased data transfer rate by increasing the number of alternative routing paths and the reduced energy consumption rate.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.2
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• pp.89-96
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• 2016

The High Efficiency Video Coding (MPEG-H HEVC/ITU-T H.265) is the newest video coding standard which has the quadtree-structured coding unit (CU). The quadtree-structure splits a CU adaptively, and its optimum CU depth can be determined by rate-distortion optimization. Such HEVC encoding requires very high computational complexity for CU depth decision. Motivated that the blob detection, which is a well-known algorithm in computer vision, detects keypoints in pictures and decision of CU depth needs to consider high frequency energy distribution, in this paper, we propose to utilize these keypoints for fast CU depth decision. Experimental results show that 20% encoding time can be saved with only slightly increasing BDBR by 0.45% on all intra case.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.311-316
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• 2006

The role of short fibre pulp - Mixed Harwood, Eucalyptus, Aspen, Birch, etc for the manufacture of different grades of paper is very well recognized. At the same time, lots of efforts are in progress to maximize the advantages while preserving their own special property. Bleached Acacia Kraft Pulp (BAKP) is comparatively new entry but gained quick recognition. BAKP was introduced to the world market by South East Asian suppliers in the late 1990's. This paper discusses in detail the role and opportunities of use of short fibre pulps. A logical technical comparison has been made between BAKP and another short fibre grades. BAKP being a short, thin-walled fibre shows several similarities with Eucalyptus pulp in terms of good bulk and stiffness. Refining energy and strength properties are very similar, but the shorter fibres and thinner cell walls give an outstanding opacity and formation compared to other commercial short fibre pulps. The collapsed and band-shaped nature gives a matchless smoothness, enabling less calendaring and exceptional printing properties. BAKP is shown to give several advantages to fine paper manufactures, compared with a number of established short fibre pulps such as Brazilian and Chilean Eucalyptus, Canadian Aspen and Indonesian Mixed Hardwood. It is important to consider refining and calendaring conditions to achieve optimum performance. For outer layers of multiply board, Acacia gives excellent coverage due to its high opacity and uniform fibre distribution. Its low roughness property gives improved printability. For tissue products, Acacia gives unique property of superior softness both in terms of hand feel and bulk softness. The high fibre population gives an impression of much higher quality due to the higher opacity and good formation.

• Korean Journal of Chemical Engineering
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• v.35 no.12
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• pp.2327-2335
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• 2018

Fluid catalytic cracking (FCC) is an important chemical process that is widely used to produce valuable petrochemical products by cracking heavier components. However, many difficulties exist in modeling the FCC process due to its complexity. In this study, a dynamic process model of a FCC process is suggested and its structural observability is analyzed. In the process modeling, yield function for the kinetic model of the riser reactor was applied to explain the product distribution. Hydrodynamics, mass balance and energy balance equations of the riser reactor and the regenerator were used to complete the modeling. The process model was tested in steady-state simulation and dynamic simulation, which gives dynamic responses to the change of process variables. The result was compared with the measured data from operating plaint. In the structural analysis, the system was analyzed using the process model and the process design to identify the structural observability of the system. The reactor and regenerator unit in the system were divided into six nodes based on their functions and modeling relationship equations were built based on nodes and edges of the directed graph of the system. Output-set assignment algorithm was demonstrated on the occurrence matrix to find observable nodes and variables. Optimal locations for minimal addition of measurements could be found by completing the whole output-set assignment algorithm of the system. The result of this study can help predict the state more accurately and improve observability of a complex chemical process with minimal cost.

• Nutrition Research and Practice
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• v.13 no.6
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• pp.488-497
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• 2019

BACKGROUND/OBJECTIVES: There are various factors that affect metabolic abnormalities related to obesity. The purpose of this study is to analyze the differences in dietary intakes and body compositions of obese women according to metabolic risks and to classify them as metabolically healthy obese (MHO) or metabolically abnormal obese (MAO). SUBJECTS/METHODS: This study was conducted on 59 obese Korean women aged 19 to 60 years. NCEP-ATPIII criteria were applied and the women classified as MHO (n = 45) or MAO (n = 14). Body composition of each subject was measured by using dual-energy x-ray absorptiometry (DEXA). Three-day food records were used to analyze dietary intake. Eating habits and health-related behaviors were determined through questionnaires. Indirect calorimetry was used to measure resting metabolic rate and respiratory rate. RESULTS: The average age of the subjects was 43.7 years. The analysis of body composition according to phenotype revealed significantly higher body fat mass (P < 0.05), arm fat mass (P < 0.05), and android fat mass (P < 0.05), as measured by DEXA, in the MAO group than in the MHO group. There was no significant difference in the dietary intake of the two groups. However, eating behaviors differed. Compared to the MHO group, the MAO women had a shorter meal time (less than 10 minutes), a preference of oily foods, and a tendency to eat until full. Therefore, the eating habits of MHO women were more positive than those of MAO women. CONCLUSIONS: The results suggest that fat distribution in each body region affects various metabolic abnormalities. A high level of arm fat mass in obese Korean women may increase metabolic risk. In addition, eating habits of obese Korean women are considered to be environmental factors affecting the metabolic phenotype of obese Korean women.