• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.4
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• pp.1-11
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• 2001

This study was carried out to analyze the characteristics of forest environmental and stream morphological factors by using the quantification theory(I) for evaluation of the watershed stability. Present annual mean sediment yield of erosion control dams were investigated in 167 sites of erosion control dam constructed during 1986 to 1999 in Gyeongbuk. The results obtained from this study were summarized as follows; According to the coefficients of partial correlation, each factor affecting to sediment was shown in order of gravel contents, number of first streams order, number of total streams, length of total streams, forest type, length of main stream, parent rock, stand age, soil texture, stream order, slope gradient, soil depth and aspect. Descriptions of class I were as follow; Igneous rock of parent rock, hardwood stands of forest type, less than 20 year of stand age, less than 30cm of soil depth, sandy clay loam of soil texture, more than 41% of gravel contents, south~east of aspect, 2,501~3,500m of length of main stream, 21~25 of number of total streams, 5,501~10,000m of length of total streams, 3 or more than 4 of stream order, more than 16 of number of first stream orders and more than $31^{\circ}$ of slope gradient. Descriptions of class II were as follow; Metamorphic rock of parent rock, coniferous stands of forest type, more than 25 year of stand age, 31~40cm of soil depth, silt loam of soil texture, 11~20% of gravel contents, north~west of aspect, 2,501~3,500m of length of main stream, 16~20 of number of total streams, 3,501~5,500m of length of total streams, 3 of stream order, 11~15 of number of first stream orders and more than $31^{\circ}$ of slope gradient. Descriptions of class III were as follow; Sedimentary rock of parent rock, mixed stands of forest type, more than 25 year of stand age, more than 51cm of soil depth, silty clay loam of soil texture, less than 10% of gravel contents, south~west of aspect, less than 500m of length of main stream, less than 5 of number of total streams, less than 1,000m of length of total streams, less than 1 of stream order, less than 2 of number of first stream orders and less than $25^{\circ}$ of slope gradient. The prediction method of suitable site for erosion control dam divided into class I, II, and III for the convenience of use. The score of class I evaluated as a very unstable area was more than 8.4494. A score of class II was 8.4493 to 6.0452, it was evaluated as a moderate stable area, and class III was less than 6.0541, it was evaluated as a very stable area.

• Health Policy and Management
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• v.13 no.4
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• pp.99-114
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• 2003

This study was performed to determine the effect of social class distribution as measured by lower social class rate on all cause and cause specific mortality in Korea. I obtained data on social class, fiscal autonomy of municipalities, number of medical doctors, region(Si/Gun) from 1955 Korea Census Data and Regional Statistics Data. And all of the data on mortality adjusted for age for 1995 for each district from the National Statistics Office. Lower social class rate ranged from 18.9％ for Kangnam gu to 85.7％ for Imsil gun and age standardized mortality ranged from 385/100,000 population for Kangnam go to 803/100,000 population for Sinan gun. Lower social class showed had a significant correlation with total mortality adjusted for age(r=0.81, p<0.0001). The association of the rate to total mortality remained highly significant after adjusted for number of medical doctors per 1,000 population, fiscal autonomy of municipalities and region(p<0.0001). Effects of the lower social class were also found for neoplasm (p=0.0008)； cardiovascular disease (p<0.0001)； infectious disease(p=0.0115)； respiratory disease(p=0.0085)； gastrointestinal disease(p<0.0001)； accident ＆ poisoning (p<0.0001). The findings suggest that policies that deal with the inequality in social class may have an important impact on the health of the population.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.4
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• pp.445-453
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• 2013

Walleye pollock Theragra chalcogramma fisheries in Korean waters have changed dramatically during the last three decades: the highest catches occurred in 1981, followed by continuous decreases through the 1990s, ending with a complete collapse of the population in the 2000s. The major spawning ground of walleye pollock is located in North Korean waters, and some juveniles (called nogari in Korean, <300 mm) migrate to the south for feeding and growth. Since the 1960s, Korean fishermen have often caught juveniles, and the weight (metric tons) of juvenile catch was recorded from 1975-1997. However, because the walleye pollock were not aged, the population age structure was not delineated. We developed a model to estimate the number of walleye pollock of each size class based on catch statistics of adults and juveniles, the catch proportion of each size class, and length and weight information on specimens collected by Danish-seine and drift-gill-net fisheries. The model results demonstrated that the recruitment size of walleye pollock was consistently within the 200-250mm size class, and the highest number of this size class occurred in 1981, although values greatly fluctuated interannually. The number of juvenile pollock was 10.4 times higher than that of adult pollock during 1975-1997. The total yield of juvenile pollock was 0.95 million tons, which was equivalent to about 68.2% of total pollock production. The number of juvenile pollock caught during the same period, however, was 16 billion, comprising about 91.2% of the total number caught. Such high fishing pressure on juvenile pollock is considered one of the main factors causing the collapse of the pollock population.

• Journal of the Chungcheong Mathematical Society
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• v.27 no.2
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• pp.183-203
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• 2014

We examine fundamental units of quadratic function fields from continued fraction of $\sqrt{D}$. As a consequence, we give another proof of geometric analog of Ankeny-Artin-Chowla-Mordell conjecture and bounds for class number, and study real quadratic function fields of minimal type with quasi-period 4.

• Korean Journal of Mathematics
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• v.26 no.2
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• pp.293-297
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• 2018

In the paper [4], we constructed 3-part of the Hilbert class field of imaginary quadratic fields whose class number is divisible exactly by 3. In this paper, we extend the result for any odd prime p.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1133-1138
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• 2010

In the anti-collision scheme proposed by EPCglobal Class-1 Gen-2 standard, the frame size for a query round is determined by Q-algorithm. In the Q-algorithm, the reader calculates a frame size without estimating the number of tags in it's identification range. It uses only the slot status. Therefore, Q-algorithm has advantage that the reader's algorithm is simpler than other algorithms. However, it cannot allocate an optimized frame size because it does not consider the number of tags. Also, the conventional Q-algorithm does not define an optimized parameter value C for adjusting the frame size. In this paper, we propose a modified Q-algorithm and evaluate the performance with computer simulations. The proposed Q-algorithm estimates the number of tags at every query round, and determines the parameter value C based on the estimated number of tags.

• International Journal of Computer Science & Network Security
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• v.23 no.9
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• pp.129-133
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• 2023

Classification or prediction problem is how to solve it using a specific feature to obtain the predicted class. A wheat seeds specifications 4 3 classes of seeds will be used in a prediction process. A multi linear regression will be built, and a prediction error ratio will be calculated. To enhance the prediction ratio an ANN model will be built and trained. The obtained results will be examined to show how to make a prediction tool capable to compute a predicted class number very close to the target class number.

• Journal of Korean society of Dental Hygiene
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• v.20 no.1
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• pp.63-71
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• 2020

Objectives: This study provides basic data for developing practical teaching methods enabling efficient execution of the dental hygiene care process. Methods: A total of 197 dental hygiene students experienced in dental hygiene care process in Gwangju and Jeonnam were surveyed from June 1 to August 30, 2019 to study their class flow, professors-student relationships, and class satisfaction level. Post survey, statistical analysis was performed using frequency analysis, independent t-test, Pearson's correlation analysis, and multiple regression analysis. Results: 1. Class fl ow was high in three lecturers (3.56), four hours per week (3.39), and four hours per week (3.94). Class satisfaction was high in three lecturers (3.99) and four hours per week (3.90) (p<0.05). 2. There was a positive correlation between class flow and professor-student relationship (r=0.519), class fl ow and class satisfaction (r=0.566), and professor-student relationship and class satisfaction (r=0.838) (p<0.01). 3. The factors influencing class fl ow were the number of lecturers (β=0.442), class hours per week (β=-0.397), and class satisfaction (β=0.385). Conclusions: Apart from finding ways to improve class satisfaction for class flow in the dental hygiene care process, efforts are required to increase the number of lecturers and class hours per week for efficient class management. Further research is needed to develop practical teaching methods.

• Honam Mathematical Journal
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• v.36 no.1
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• pp.147-155
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• 2014

Let D be a square-free positive integer and let $K_D=\mathbb{Q}(\sqrt{-D})$ be the imaginary quadratic field. And let $h_D$ be the class number of the number field $K_D$. In this paper, we show the following: If D=l or 4l, where l is a prime number with $l{\equiv}3$ (mod 4), then $h_D$ is odd.

• Journal of Technologic Dentistry
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• v.33 no.3
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• pp.227-236
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• 2011

Purpose: The purpose of this study was to reduce the remake rate of dental prosthesis. We examined remake cause and major factor of dental prosthesis to determine methods for raising dental prosthesis satisfaction. Methods: Subjects included dental technicians in the metropolitan areas of the cities of Daegu and Gyeong-buk. Surveys were filled out by consenting dental technicians. Statistical analysis was done using SPSS version 19.0 for Windows. We determined frequencies and percentage, calculating means, and standard deviations, and determining statistical significance using t-tests, analysis of variance. Results: Impression or material transform is high among remake cause and margin is high among remake major factor. Crown class showed differences in General characteristics associated with age, number of employees, and number of connection dental. Porcelain class showed differences in General characteristics associated with age, number of employees, and number of connection dental. Denture class showed differences in General characteristics associated with age, monthly salaray, and career. Implant class showed differences in General characteristics associated with age, education, and career. Conclusion: In order to reduce remake rate of dental prosthesis, communication of dentist, dental technician, and the patient are require and correct information of patient and dental prosthesis are need.