• Korean Journal of Agricultural Science
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• v.4 no.2
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• pp.344-390
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• 1977

The purpose of this paper was to schedule optimum cutting strategy which could maximize the total yield under certain restrictions on periodic timber removals and harvest areas from an industrial forest, based on a linear programming technique. Sensitivity of the regulation model to variations in restrictions has also been analyzed to get information on the changes of total yield in the planning period. The regulation procedure has been made on the experimental forest of the Agricultural College of Seoul National University. The forest is composed of 219 cutting units, and characterized by younger age group which is very common in Korea. The planning period is devided into 10 cutting periods of five years each, and cutting is permissible only on the stands of age groups 5-9. It is also assumed in the study that the subsequent forests are established immediately after cutting existing forests, non-stocked forest lands are planted in first cutting period, and established forests are fully stocked until next harvest. All feasible cutting regimes have been defined to each unit depending on their age groups. Total yield (Vi, k) of each regime expected in the planning period has been projected using stand yield tables and forest inventory data, and the regime which gives highest Vi, k has been selected as a optimum cutting regime. After calculating periodic yields and cutting areas, and total yield from the optimum regimes selected without any restrictions, the upper and lower limits of periodic yields(Vj-max, Vj-min) and those of periodic cutting areas (Aj-max, Aj-min) have been decided. The optimum regimes under such restrictions have been selected by linear programming. The results of the study may be summarized as follows:- 1. The fluctuations of periodic harvest yields and areas under cutting regimes selected without restrictions were very great, because of irregular composition of age classes and growing stocks of existing stands. About 68.8 percent of total yield is expected in period 10, while none of yield in periods 6 and 7. 2. After inspection of the above solution, restricted optimum cutting regimes were obtained under the restrictions of Amin=150 ha, Amax=400ha, $Vmin=5,000m^3$ and $Vmax=50,000m^3$, using LP regulation model. As a result, about $50,000m^3$ of stable harvest yield per period and a relatively balanced age group distribution is expected from period 5. In this case, the loss in total yield was about 29 percent of that of unrestricted regimes. 3. Thinning schedule could be easily treated by the model presented in the study, and the thinnings made it possible to select optimum regimes which might be effective for smoothing the wood flows, not to speak of increasing total yield in the planning period. 4. It was known that the stronger the restrictions becomes in the optimum solution the earlier the period comes in which balanced harvest yields and age group distribution can be formed. There was also a tendency in this particular case that the periodic yields were strongly affected by constraints, and the fluctuations of harvest areas depended upon the amount of periodic yields. 5. Because the total yield was decreased at the increasing rate with imposing stronger restrictions, the Joss would be very great where strict sustained yield and normal age group distribution are required in the earlier periods. 6. Total yield under the same restrictions in a period was increased by lowering the felling age and extending the range of cutting age groups. Therefore, it seemed to be advantageous for producing maximum timber yield to adopt wider range of cutting age groups with the lower limit at which the smallest utilization size of timber could be produced. 7. The LP regulation model presented in the study seemed to be useful in the Korean situation from the following point of view: (1) The model can provide forest managers with the solution of where, when, and how much to cut in order to best fulfill the owners objective. (2) Planning is visualized as a continuous process where new strateges are automatically evolved as changes in the forest environment are recognized. (3) The cost (measured as decrease in total yield) of imposing restrictions can be easily evaluated. (4) Thinning schedule can be treated without difficulty. (5) The model can be applied to irregular forests. (6) Traditional regulation methods can be rainforced by the model.

• The Journal of Fisheries Business Administration
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• v.19 no.2
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• pp.1-58
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• 1988

The purpose of this study is to investigate the relation between social education and secondary education of seaside and sea village schools for supporting the successors to fishery. Objects of the study were five groups; 321 fishermen, 107 staff members of a Fishery Guidance Center, 1, 001 students, 306 teachers of sea villages, 193 staff members of a Fishery Cooperative Association. The total number of people being object of this study was 1, 876 persons. The questionaire used for this study was made after preliminary counseling with fishermen in sea villages and teachers in seaside schools. The results of this study are as follow ; 1) About the value of Fishery and successors to Fishery There have been more positive responses than negative ones to the question on the value of fishery. The main reason for positive responses lies in the potentiality for development of fishery but the negative responses are because of the heavy work. 56.8% of the respondents expected an increasing number of successor to fishery, but 43.2% of the respondents had a negative foresight on that problem. The negative respondents stated that the fisherman that moved from the sea villages to the urban areas are responsible for the none increasing numbers of successors to fishery. Most of the respondents answered that government support is needed in order to increase the number of successors to fishery. 2) Social education for Fishermen Only 40% of fishermen know the Fishing Village Guidance Center as the main institute for social education. 94.17% of the respondents prefer plural institutes to single ones. 5.9% of the respondents answered with opposit opinions. 40.4% of the respondents answered that technical teachings has not often been practised. The reason why technical teaching does not often come into effect are as follows; lack of technical expertise, insufficient concern of staff members of the Guidance Center or the Cooperation Association. Also fishermen answered that the Fisherman Guidance Center does not often practise technical education. The Fishery Cooperation Association with its social education for fisherman takes the role of education for the economical way and carries out financial assistance. The relationship between the Fishery Cooperative Association and fishermen is presented satisfactory. However, the frequency of education is not satisfactory. Indifferences between staff members of the Fishery Cooperative Association does not carry out fishery education very often. Also loaned money matters were not satisfactory. 3) Secondary education for Fishery This study showed that it is desirable that the practical course of middle schools in islets and seaside villages take education on fishery ; however, a few schools only take the practical course fishery. Most of the fishery high schools want computer education as a new recommendable course. The students of fishery high schools want computer education as a new recommendable course. The students of fishery high schools have problems with scientific terms in the text books for the practical of fishery high schools have problems with scientific terms in the text books for the practical courses. Over 80% of the respondents agreed that the principals of schools in islets and sea side villages should be men having majored in fishery. 4) The connection between social education and secondary education for fishery a. It is desirable that the principal and vice principal of secondary schools in islets and sea side villages are men majored in fishery. b. It is recommendable that fishery courses are taken as practical courses in fishery village schools for it is helpful to relate between the vocation and the district's special character, as well as to built up relation between the middle school education and the fishery high school education. c. The teachers of fishery high schools and the officials of government offices which are related to fishery should work together to realize a program on teaching various kinds of techniques and give other useful informations to fishermen. d. During the vacations the fishery high school could be used for the social education of fishermen. Seminars on fishery technique and cultural aspects could be held. Especially a spiritual education which is needed for the improvement of the society of fishermen could be achieved by a cultural education. e. On the state level a financial support to raise the number of successors to fishery, a national policy for the betterment of the life of fishermen, as well as active publicity activities are necessary. f. A financial support of the government for raising the number of the successors to fishery is needed. For this purpose a fishery education performed on a state level would be desirable.

• Korean Journal of Rural Living Science
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• v.5 no.2
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• pp.135-144
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• 1994

This study was carried out to investigate health status and nutritional status based on dietary intake and food habit of elderly women in rural area of Keyonggi Province. The subject of this study were 133 elderly women aged 60 and over and interviewed with a questionaire. Main result was as follows : 1) Health score based on modified Cornell Medical Index, CMI(45 out of 195 items) was the average $29.1\pm6.8$ and was not significantly different with family size educational level and farmwork participation. In age, 44.0% of the subject in 60~65 years old was low score of CMI(11~25), but 50% of the subject in older than 80 years old was high score(33~44). The subject with disease was 82% and disease of musculoskeletal system was main type. 2) Dietary intake data obtained by a semiquantitative food frequency questionaire showed the average daily intake of energy, protein, Ca, retinol and riboflavin was lower than RDA Daily energy, protein and Ca intake was individually 84%, 67% and 55.1%. It was retinol that was the least sufficient as 49.1% of RDA. 3) The relation between CMI score(divided into three level : low, middle and high) showed low level was significantly different with others according to daily intake of energy, protein, retinol, thiamin, riboflavin and ascorbic acid. The correlation between CMI score and all nutrient intake were highly significant (p＜0.001), thus we knew that health status was affected importantly by nutrient intake. 4) Family size, educational level and age showed not significant correlation with all nutrient intake. 5) In food habit, 84.8% of the subject had regular mealtime and 14.4% were skip meal sometimes. The main reason of skip meal was a poor appetite. Preference for salty taste of subject was insufficiently salty of somewhat salty. Preference for fishes and meats showed the subject consumed fishes more than meats, but 23.5% of the subject didn't consume both. The subject eaten supplement was 38.3%.

• Journal of Korean Society of Forest Science
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• v.29 no.1
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• pp.102-114
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• 1976

This experiment was conducted to investigate the percentage of fertile seed in terms of crossabilities and relationships of taxonomic affinities for the ${\times}$ P. rigitaeda of interspecific hybrid, ${\times}$ P. rigida rigitaeda and ${\times}$ P. rigitaeda rigida of backcross hybrids, $F_2$ of ${\times}$ P. rigitaeda and natural hybrid of ${\times}$ P. rigitaeda within Sub-genus Diploxylon of the Genus Pinus. The possibility of establishment of hybrid seed orchard and differentia of hybrids for the purpose of extensive program of reforestation in the future have also been investigated. And, the experimental results obtained are summarized as follows: 1. On the basis of crossabilities as well as on the taxonomic affinities according to the systems of Shaw, Pilger and Duffield, it has been proven that the parental species of those hybrids are of close affinities and range of the fertile hybrid seed production rate was as high as 67-87% in the best hybrid combination (Table 6). 2. Those hybrids seemed to be most promising in the growth perfermance exhibiting 28-80% more volume growth compared to the P. rigida with the statistic significance of 1-5% level (Table 7, 8, 9). And all hybrids exhibit cold hardiness as much as P. rigida except $F_1$ hybrid of ${\times}$ P. rigitaeda and it seems to suggest that the characteristics of cold hardiness were transmitted from the P. rigida. 3. With regard to the anatomical characteristics of needle, the hypoderm is biform in most of the hybrid pines and the characteristics of resin canals are medial in all hybrid. And, the fibrovascular bundles are intermediate of both parent in all hybrid. Therefore it was found to be possible to distinguish the hybrids pines from their parents by the needle characteristics (Table 10). 4. It has been demonstrated that the hybrids pines have a phenolic substance (No. 7) of pale yellow at Rf-0.66, same as P. rigida, but no trace of phenolic substance was observed in the P. taeda. This fact will serve as an important criteria for early identification of hybridity in progeny testing (Table 11). 5. It was found to be possible to distinguish by the starch gel electrophoretic variations banding patterns and staining densities of isoperoxidase in the needles of the hybrids pines from their parents (Fig. 1).

• Journal of Dairy Science and Biotechnology
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• v.34 no.4
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• pp.255-262
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• 2016

This study was conducted to investigate the difficulties of dairy farms in practicing 6th industrialization and methods for overcoming these difficulties. A qustionnaire survey was carried out to examine the present states of farms, recognition of the farmstead milk-processing market situation, possibility of farmstead milk processing for reducing the raw milk surplus, assessment of government policies, and difficulties dairy farmers confront in realizing the 6th industrialization. Farm sizes, types, and human resources organizations varied between farms. Most farmers were producing yogurt and/or fresh (string or barbecue) cheeses, which were marketed through 'Visit and Purchase' channel. Farmers who answered the questionnaire were relatively positive about the current situation of farmstead milk processing, expecting to be involved in the disposal of excess raw milk. Nevertheless, they responded negatively about current relevant policies, citing the main difficulties caused by 'excessive regulation'. Other barriers to successful '6th industrialization' are difficulties in marketing and lack of funds. Approximately 19% of dairy farms practicing the '6th industrialization' use automatic milking system (AMS) and 38.46% of dairy farmers whose milking depends on conventional milking system intend to introduce AMS in the future. Positive expectations of AMS adoption were mostly related to 'lack of time and labor', 'exhibiting for tourism', and 'succession of dairying'.

• Journal of Korean Society of Forest Science
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• v.104 no.2
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• pp.187-192
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• 2015

Individuals in the population under a particular environmental condition influencing recurrently for a long time could locally adapted and local adaptation is of a fundamental importance in a breeding program, conservation activities of genetic resources or evolutionary biology. Plants at northern range limits have higher probability of expressing an adaptative genetic trait. The natural community at the northern range limit of Ilex cornuta (Chinese holly) in Buan, Jeollanam-do in Korea was composed of adults of 744 and seedlings of 211 (hereafter Community) and is designated as the Korean Natural Monument (No. 122) by the law. At two adjacent areas to Community, 85 (hereafter Plantation I) and 27 hollies (hereafter Plantation II) were planted respectively for preparations of the next generation. Eighty-five trees were sampled for genetic analysis in the three groups. Fifty-two (36%) of the total 143 amplicons were polymorphic from four AFLP primer combinations. A total of thirteen genotypes was identified and just one genotype was for 52 trees of Community. Seven and five genotypes were shown for Plantation I and II, respectively. There was no identical genotype between Community and Plantation (I or II) or between two plantation groups. Number of private loci was 2 for Community, 6 for Plantation I and 4 for Plantation II. We presumed their genetic backgrounds were quite different with one another and the plantation groups were made independently because they were different not only the genetic compositions but also their ages. Considering the genetic monomorphism by AFLP markers, observations of only male trees and asexual propagation as layerage or cuttage, the hollies in Community might be a genet by root suckering from a single male tree, not the results of selective removal of female trees for ornamental use in the past.

• Korean Journal of Environment and Ecology
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• v.26 no.4
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• pp.559-575
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• 2012

This study, targeting Namhan Mountain Fortress which was designated as a No. 57 national historic site and placed on the World Heritage Tentative List in 2010, was intended to identify the change of vegetation structures by reviewing past references, pictures, research data and additionally conducting a site survey. Also, it was designed to draw up measures for restoring vegetation suitable for historically and culturally valuable Namhan Mountain Fortress. According to the biotope mapping of study site, Quercus spp. forest distributed a greatest part of area with 40.8% of $2,611,823m^2$. Pinus densiflora forest, highly likely to go through ecological succession, was dispersed in the whole region of Cheongryangsan, the area from West Gate to North Gate and the ranges between South Gate to Cheongryangsan with taking 16.5%. Pinus densiflora forest with a low probability of succession amounted to 4.7% and was dispersed mainly in the forest behind Namhansan elementary school. Pinus densiflora going on the ecological succession is distributed a portion of 2.9%. And the currently dying out Pinus densiflora forest amounted to 2.1%. As a result of analysis of the vegetation structure for 19 years, the succession from Pinus densiflora forest to Pinus densiflora and succession from Quercus spp. mixed forest to Quercus spp. forest to Carpinus laxiflora forest were predicted. Additionally, Quercus spp. expanded its dominance over time. According to the characteristics of each classified zone, the site was categorized into $553,508m^2$ area of Pinus densiflora forest area for the landscape maintenance, $114,293m^2$ area of Pinus densiflora forest area for the landscape restoration, $205,306m^2$ area of Pinus densiflora forest area for the disclimax, and $1,169,973m^2$ area of Pinus densiflora forest area for inducing ecological succession.

• Journal of Wetlands Research
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• v.1 no.1
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• pp.29-44
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• 1999

Vegetation structure and distribution of the vascular hydrophytes and hygrophytes, and the growth pattern, standing crop and amounts of nutrient uptake by Salix species were investigated in the upper stream wetlands of the Namgang-Dam, Chinju-city, Gyeongsangnam-do, Korea from April to November in 1997. The flora was composed of 43 hydrophytes and 241 hygrophytes, or total 284 vascular plants. The life forms of the hydrophytes were classified as 27 kinds of emergent plants, 4 floating-leaved plants, 3 free-floating plants, and 9 submersed plants. In the herb layer, the dominant species was Persicaria hyciropiper, and the ranges of the species diversity indices (H'), equitabilities, (J') and community similarity indices (CCs) were 1.59~1.89, 0.87~0.96, and 0.35~0.83, respectively. In the shrub and subtree layers, 17 kinds of Salix species were supposed to the pioneer plants at the early stage of the succession. The number of branches per main stem of Salix species was 5.0. The DBH class-frequency histograms of Salix species were the reverse J type, and the natural regeneration of the Salix community was expected. Basal area of Salix species per square meter was $24.87cm^2$. Volume of Salix species per square meter was $12,008cm^3$ and total phytomass of the Salix species was estimated as 12,894 ton. Biomass distribution of Salix species in the stem, the branch and twig, and the leaf was 64.1%, 28.1%, and 7.8%, respectively. The amounts of nitrogen and phosphorus absorbed by Salix species were 68,022 and 19,823 kg. It was recommended that application and conservation of the wetland and other counterplans are indispensable to reduce the adverse effects of water pollution and to preserve the wetland ecosystem.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.1
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• pp.1-19
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• 2022

The Geumgang Pine (Pinus densiflora) Forest in Sogwang-ri, Uljin has traditionally been a pine tree protection area (prohibited forest) for timber production purposes, and is now designated and managed as a protected area for forest genetic resource conservation by the Korea Forest Service. This study, we analyzed topographical characteristics, existing vegetation, tree age, and plant community structure, and proposed a sustainable management method for the Geumgang Pine (Pinus densiflora) Forest in Sogwang-ri, Uljin for timber havesting purposes. The topographical characteristics of the target area were 36.7% ridges and 38.7% valleys; the ratio of ridges to valleys was similar, and the slopes formed 24.7% of the total area. The types of pine forest communities are divided into six types based on the progress of pine forest renewal, the competition with other species such as deciduous broadleaf trees, and the formation of layered structures. It has been confirmed that the age of the large-diameter pine trees (40~60cm in diameter) is approximately 60~70 years, which is relatively low. As a result of the analysis of the relative importance percentage and layered structure, differences depended on the progress of the pine forest renewal project, and not only the maintenance of the pine forest, but also the creation of a secondary growth forest, the density adjustment of pine trees, and the active management of competitive trees. The average basal area by the community was 12,642.1~25,424.4cm² for the tree layer and 1.8~1,956.5cm² for the low tree layer based on a quadrat of 400m². The difference in the basal area appeared to depend on the size and number of trees forming the tree layer and the degree of pine forest renewal (the degree of time elapsed after thinning pine trees). The average number of species that appeared in each community was 8.7-20.3; there were many species located in valleys, and the type competes with deciduous broadleaf trees due to the lack of management. The diversity of species ranged from 0.6915-1.0942, and was evaluated as low compared to pine communities in central temperate zones. In this paper, we determined the management goals of Geumgang Pine (Pinus densiflora) Forest in Sogwang-ri, Uljin to produce timber with high economic value, and suggested efficient vegetation management for continuous afforestation, the establishment of a timber production system, and improvement of wood production as a management direction.

• Analyses & Alternatives
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• v.6 no.1
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• pp.115-162
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• 2022

The Rules of the Workers' Party of Korea (WPK), revised at the eighth Party Congress in 2021, reflect the Kim Jong Un regime's changes in strategic lines and ideological justifications on North Korea's socialism and communism, and its recent stances against the external environment. Moreover, they contain critical changes in the party's organizational system encompassing the central and the provinces. This study explores the organizational changes of the "monolithic guidance system of the party core" stipulated by the new party rules in January 2021, based on the analysis of the entire nine revised rules of the WPK since 1945. In the 2021 Party Congress, the Kim Jong Un regime, which officially came to power after the fourth Party Conference in 2012, has institutionalized the monolithic guidance system centered on the party core, or the head of state, Kim Jong Un. The newly set leadership and execution system, which reorganized party, government, and military organizational structure and accompanied the relevant personnel changes, was derived from the attempts for reinstating the Kim Jong Un regime as a more normalized party-state structure before its 10th year in power in April 2022. The "monolithic leadership system of the party core" established a system of "organizational leadership" through the organization of the Central Committee, directed by the Party Head, or General Secretary. The institutionalization of the new system resulted from the ten-year development of the revival of the party-state structure, which compromised the status of the military and reconfirmed the party's control of the military. This study explains the new system from the perspectives of both institutionalization and top-down unity, shedding light on the new party-military-government relations of the Kim Jong Un regime. The analysis contributes to a better understanding and forecasting of the Kim Jong Un regime's governance, which currently strengthens the monolithic leadership system as a crisis management system in the face of the "triple hardships" of sanctions, Covid and disaster.