The purpose of this study was to compare the effects of citric acid and tetracycline HCI application to the root surfaces of periodontally diseased teeth on the proliferation and spreading of human periodontal ligament cells. The roots were prepared so that the comparison could be made among root planed, citric acid treated and tetracycline HCI treated surfaces. In the cell proliferation experiment, human periodontal ligament cells at a concentration of
Purpose: Recently, Department of Nuclear Medicine have an interest in Video Display Terminals (VDT) syndrome including musculoskeletal disorders, ophthalmologic disorders, trouble of electromagnetic waves and stress disorders occur to VDT workers as the growing number of users and rapid pace of service period supply in large amount. This study research on the actual condition for VDT syndrome in Nuclear Medicine, Seoul National University Hospital (SNUH), discover the problem and draw a plan of upcoming improvement. The aim of this study establish awareness about VDT syndrome and is to prevent for it in the long run. Materials and Methods: Department of Nuclear Medicine, SNUH is composed Principle part, Pediatric part and PET center. We estimated risk factors visit in each part directly. Estimation method use "Check list for VDT work" of Wonjin working environment health laboratory and check list is condition of VDT work, condition of work tables, condition of chairs, condition of keyboards, condition of monitors, working position, character of health management and other working environment. Analysis result is verified in Department of Occupational and Environment, Hallym University Sacred Heard Hospital. Results: As a result of analysis, VDT condition of Department of Nuclear Medicine, SNUH is rule good. In case of work tables, recent of things are suitable to users upon the ergonomical planning, but 15% of existing work tables are below the standard value. In case of chairs are suitable, but 5% of theirs lost optimum capacity become superannuated. The keyboards are suitable for 98% of standard value. In case of monitors, angle control of screen is possible of all, but positioning control is impossible for 38%. In case of working position, 10% is fixed positioning for long time and some of the items researched unsuitable things for standard. At health management point, needed capable of improvement. Also, other working condition as lighting, temperature, noise and ventilation, discovered the problem, but is sufficient to advice value. Conclusion: VDT syndrome is occurrences of possibility continuously, come economical expensive about improvement, is inherent in various causes and originate without your knowledge. So, there is need systematic management system. In Nuclear Medicine, VDT syndrome make it better that constant interest and effort as improvement of ergonomical working environment, improvement of working procedure, regular exercise and steady stretching, and can be prevented fairly. This promote physical and mental condition of worker in top form in comfortable working environment, so this is judged by enlargement of operations efficiency and rising of satisfaction ratings of the inside client.
The purpose of this study is to present a model for enhancing the academic excellence of adult college students. For this purpose, 408 adult college students attending 2-year and 4-year colleges in Busan, Daegu, and Gyeongbuk were surveyed and analyzed. The components of the model are curriculum, educational methods, evaluation of education, educational administration, educational environment, and institutional support and the results are as follows. First, the curriculum preferred by adult college students was to acquire diverse academic knowledge for a degree, to acquire knowledge and skills to develop skills for the workplace, and to acquire new information and knowledge regarding issues in society as a whole. Second, the professors' qualification among the educational methods preferred by adult college students was professional competence of the professors based on their theoretical and practical skills. The preferred teaching methods were lecture, discussion, action learning, and the project learning method in that order and video and PowerPoint were preferred as effective teaching mediums. Third, the preferred course for adult college students is operated on weekends, and three years was preferred to get a bachelor's degree. The possible hours of learning per day is 3~6 hours, indicating the necessity of e-learning, B-learning, and prior learning experience recognition systems. Fourth, the education evaluation method preferred by adult college students was a compromise method which is a mixture of absolute evaluation and relative evaluation, and it also showed the need for Pass or Non Pass evaluation method. Fifth, the internal factors of college selection preferred by adult college students were the acquisition of new knowledge and skills, and the external factors were desire to receive many opportunities related to employment and job improvement. The classroom, which provides an effective environment, was a fixed seat classroom and an indoor classroom environment was emphasized for desired educational environment. Sixth, institutional support preferred by adult college students was computer-related programs and learning club support services.
This study was conducted to investigate the dietary behavior and image and preference of Japanese foods. The Subjects were consisted of 570 university students(243 males and 327 females) in Daegu and Kyungbuk area, Korea. The students responses to the 10 questions about image of Japanese foods were also measured on 5 point Likert scale. Data were presented by using frequency, percentage, chi-square test and T-test. The results of this study were as follows: (1) On the eating habits, 'the whole family has breakfast together with same foods everyday'scored high as 42.3％ and 'foods put in a big platter by gathering everyday'as 35.8％. (2) About the eating customs, 53.5％ of the subjects responded that the seat was fixed at meal time, 56.4％ didn't start to eat before the patriarch started a meal and 30.9％ responded that the head of a family had more foods in number and quantity. (3) On the table manners, 13.4％ of the subjects were scolded about 'watching TV on eating', 11.5％ about 'making left-over foods', 8.0％ about 'misuse of spoon and chopsticks'. (4) The preferred ethnic foods by University students was in other of Korean, Chinese, Italian, Japanese and French foods. (5) Among subjects, 93.8％ had no experience of visiting Japan and 92.6％ wanted to visit Japan. Images on the Japanese foods were 'the price is too expensive' (mean 4.15) and 'the decoration is wonderful'(mean 4.05). But the subjects did not think Japanese foods as 'hot'(mean 2.21) and 'greasy'(mean 2.51). (6) The favorite Japanese food of subjects was Udon(mean 3.98), Sushi(mean 3.85) and Tempura(mean 3.69). So Udon turned out to be the most popular Japanese foods by university students in Daegu and Kyungbuk area, Korea. But they did not prefer Natto(mean 2.68), Ochazuke(mean 2.76), Okonomiyaki(mean 2.87) and Misosiru and did not eat. From the above results, Korean university students preferred Udon to Natto among Japanese traditional foods, and they estimated Japanese foods as 'too expensive'. Therefore, lowering the price and developing the cooking method for Korean taste were needed to increase the intake of Japanese traditional foods by Korean university students and.
The purpose of this thesis is to derive a unit hydrograph which may be applied to the ungaged watershed area from the relations between directly measurable unitgraph properties such as peak discharge(qp), time to peak discharge (Tp), and lag time (Lg) and watershed characteristics such as river length(L) from the given station to the upstream limits of the watershed area in km, river length from station to centroid of gravity of the watershed area in km (Lca), and main stream slope in meter per km (S). Other procedure based on routing a time-area diagram through catchment storage named Instantaneous Unit Hydrograph(IUH). Dimensionless unitgraph also analysed in brief. The basic data (1969 to 1973) used in these studies are 9 recording level gages and rating curves, 41 rain gages and pluviographs, and 40 observed unitgraphs through the 9 sub watersheds in Nak Oong River basin. The results summarized in these studies are as follows; 1. Time in hour from start of rise to peak rate (Tp) generally occured at the position of 0.3Tb (time base of hydrograph) with some indication of higher values for larger watershed. The base flow is comparelatively higher than the other small watershed area. 2. Te losses from rainfall were divided into initial loss and continuing loss. Initial loss may be defined as that portion of storm rainfall which is intercepted by vegetation, held in deppression storage or infiltrated at a high rate early in the storm and continuing loss is defined as the loss which continues at a constant rate throughout the duration of the storm after the initial loss has been satisfied. Tis continuing loss approximates the nearly constant rate of infiltration (
A survey was made of 976 students who were selected among students of 5 middle schools at Taegu so that it could furnish basic knowledge about sex education of adolescents by analyzing students recognition of sex, acquaintance with the opposite-sex, sex-education, The survery took a month from Nov. 1, to Nov 30, 1991. The results of this study are summarized as follows. 1. The general characteristics of the surveyed students. The survey consisted of 332 boys middle school student & 325 girls middle school students, 157 male & 162 female students of coeducational middle schools. 32.9% of them were from the first grade, 33.2% from the second grade & 33.9% from the third grade. 35.7% of them believed in Buddhism, 19% Christianism and the mode of their living standard, 86.7%, fell on 34.7% of their parents engaged in commerce and they were followed by salary man and public officals, 93.1 % of the students, parents were alive. 44.9% of their fathers were graduates of high school and 42.2% of their mothers middle school. 2. Sexual maturity 89.1 % of the surveyed girls had experienced menstruation. The mode of first menstruation, 48.2%, was at the age of 13 and the mean of it was 12.9, 3.7% the surveyed boys had exprienced a wet drem before. The mode of the first wet dream, 40.0%, was at the age of 14 and the mean was 13.4. 21.3% of surveyed students had the experience of masturbation but the number of girls fell far short of that boys. The mode of the first masturbation, 37.0%, was at the age of 14 and the mean was 13.4. 3. The acquaintance and sexual relations with the opposite sex 1) Analyzing the students actual conditions with the opposite, I found out that 52.3% of them wanted to have any kind of relations with the opposite and that 30.25 had already had some kind of relations. 73.2% of the students having relations with the opposite thought the other sex merely as a friend and the number of students who were thinking that way was distributed evenly among schools. 28.8% of the students had got acquainted with the other sex through their frieds and there were not much difference between boys and girls in the method of getting acquainated with the opposite. About 35.2% of the students having relations with the opposite came from the third grade. 47.8% of them answered that the meeting place was not fixed and 26.4% answered that they were meeting their parthers outdoors. 60.7% replyed that they were not disturbed in their studies by the relations with the other sex. 2) Most of the students 79.4%, answered that they had never had sexual relations and 16.3% of the rest said that thery were expressing their feelings by grasping each other's hand. 3) 16.6% of the surveyed students asid that they had the exprience of smoking, 1.1 % of an illusion caused by inhaling chemical addhesives, 44.0% of drinking and 41.4% of warching pornographic films. 4. The knowledge and attitude about the sex 1) The distribution and analysis according to schools and grades : 64.8% of the surveyed students answered correctly to the questions about mensturation, 49.3 % did so about wet dreams, 94.3 % did so about conception, 60.6% did so about child birth, 73.9% did so about AIDS and 50.1 % did so about sexual diseases. Roughly speaking, they had not much knowledge of sexual diseases. 2) The recognition of sex according to schools and grades : 39.0% of the students said that they had worries about sex. 33.1 % of what they worried was concerned with their bodies and 26.8% was about the acqaintance and relationship with the opposite sex. The girls were much more concerned about the former and the boys the latter. 51.1 % of the students asid that they had no specific opinion of masturbation but 19.2% said that's alright if self-restrained. About the sexual intercourse before marriage, 75.7% said negatively. 5. The need for sex education most of the students, 99.4% said they needed sex education and there was not much difference in that thought among schools. And 49.7% answered that schools, families, and societies were equlally important in sex education. About half of the students, exactly 50.2%. considered it as the main reason of sex education to prevent accidents cauesd by ignorance of sex. 81.4% said that they had had some kind of sex education. Most of the educations, 87.0%, had taken place at schools but 5.2% said they were getting most of the knowledge about sex from therir friednds, juniors and seniors. 59.5% of the students who had ever had a sex education said "Just so, so" when asked of the level of their contentment but the number of students who said "satisfied" was only a few, 16.1 %. 20.7% of the survered answered that thery wanted sex education to be made in the course of home life, and 26.6 % of the students most wanted to know about the acquaintance and relationship with the oppostie sex, 29.0% preferred nurse teachers as proper councellors of sex education. The mode of their present councellors, 42.0%, was friends but only 7.6% answered they dicussed with teachers. 6. The correlation analysis between general characteristcs and sexual behaviors of the surveyed students revealed that sex had a signigicant(P<0.001) positive correlation with parents' love toward students(P<0.01), the experience of masturbation, smoking, an illusion caused by inhaling chemical adhesives and the experience of watching pornographic films. And the standard of living had a significant(P<0.01) positive correlation(P<0.01) with grade point average, parents' existence(P<0.01) and parents' love, but a significant(P<0.01) negative correlation with sexual worries. grade point average had a significant(P<0.01)negative correlation with the experience of an illusion caused by chemical adhesives(P<0.01) and smoking. Parents' existence had significant(P<0.01) positive correlations with parents' love and smoking but a significant(P<0.01) negative correlation with the experience of an illusion by chemical adhesives. There was a significant(P<0.01) negative correlations between parents' love and the experience of an illusion by chemical adhesives, and a significant(P<0.001) positive correlation among masturbation and sexual worries, smoking, an illusion by chemical adhesives and the experience of watching pornographic films. There was a significant(P<0.001) positive correlation among acquaintance with the opposite sex, smoking, the experience of an illusion by chemical adhesives and watching pornographic films. Sexual worries had significant(P<0.01) positive correlations with smoking, the experience of an illusion by chemical adhesives and watching pornographic films. smoking had a significant positive correlation with drinking the experirence of, an illusion by chemical adhesives and watching pornographic films. Finally, there was a significant(P<0.01) positive correlation between the drinking experience and the illusion experience by chemical adhesives. According to the results mentioned above, the fact is certain that there is a great need for sex education of adolescents. Therefore, it is desirable that the schools teach sexual physiology and normal positively and that sex education including hygien education be an independant course in the curriculums. Furthermore, it is essential that the schools should have enough nurse teachers to take up sex education, expand training opportunities for them and that they develop educational materials. Considering the unbalance of the level of sex educations between boys and girls, I want to suggest that all boys and girls have sex education evenly and lead happy lives by correction irrational thought about sex, that is to say, sex discrimination, Sex education programs, especially of middle school students, should be reexamined if it is to give the students effective and profitable knowledge about sex. In addition, the government should establish a policy of adolescents' sex education to have healthy opinions of sex settled nationwide.
Currently, thanks to the major stride made in developing wired and wireless communication technology, a variety of IT services are available on land. This trend is leading to an increasing demand for IT services to vessels on the water as well. And it is expected that the request for various IT services such as two-way digital data transmission, Web, APP, etc. is on the rise to the extent that they are available on land. However, while a high-speed information communication network is easily accessible on land because it is based upon a fixed infrastructure like an AP and a base station, it is not the case on the water. As a result, a radio communication network-based voice communication service is usually used at sea. To solve this problem, an additional frequency for digital data exchange was allocated, and a ship ad-hoc network (SANET) was proposed that can be utilized by using this frequency. Instead of satellite communication that costs a lot in installation and usage, SANET was developed to provide various IT services to ships based on IP in the sea. Connectivity between land base stations and ships is important in the SANET. To have this connection, a ship must be a member of the network with its IP address assigned. This paper proposes a SANET-CC protocol that allows ships to be assigned their own IP address. SANET-CC propagates several non-overlapping IP addresses through the entire network from land base stations to ships in the form of the tree. Ships allocate their own IP addresses through the exchange of simple requests and response messages with land base stations or M-ships that can allocate IP addresses. Therefore, SANET-CC can eliminate the IP collision prevention (Duplicate Address Detection) process and the process of network separation or integration caused by the movement of the ship. Various simulations were performed to verify the applicability of this protocol to SANET. The outcome of such simulations shows us the following. First, using SANET-CC, about 91% of the ships in the network were able to receive IP addresses under any circumstances. It is 6% higher than the existing studies. And it suggests that if variables are adjusted to each port's environment, it may show further improved results. Second, this work shows us that it takes all vessels an average of 10 seconds to receive IP addresses regardless of conditions. It represents a 50% decrease in time compared to the average of 20 seconds in the previous study. Also Besides, taking it into account that when existing studies were on 50 to 200 vessels, this study on 100 to 400 vessels, the efficiency can be much higher. Third, existing studies have not been able to derive optimal values according to variables. This is because it does not have a consistent pattern depending on the variable. This means that optimal variables values cannot be set for each port under diverse environments. This paper, however, shows us that the result values from the variables exhibit a consistent pattern. This is significant in that it can be applied to each port by adjusting the variable values. It was also confirmed that regardless of the number of ships, the IP allocation ratio was the most efficient at about 96 percent if the waiting time after the IP request was 75ms, and that the tree structure could maintain a stable network configuration when the number of IPs was over 30000. Fourth, this study can be used to design a network for supporting intelligent maritime control systems and services offshore, instead of satellite communication. And if LTE-M is set up, it is possible to use it for various intelligent services.
The purpose of this paper is to explore the relations between financial constraints and dividend smoothing of innovative small and medium sized enterprises(SMEs) listed on Korea Securities Market and Kosdaq Market of Korea Exchange. The innovative SMEs is defined as the firms with high level of R&D intensity which is measured by (R&D investment/total sales) ratio, according to Chauvin and Hirschey (1993). The R&D investment plays an important role as the innovative driver that can increase the future growth opportunity and profitability of the firms. Therefore, the R&D investment have large, positive, and consistent influences on the market value of the firm. In this point of view, we expect that the innovative SMEs can adjust dividend payment faster than the noninnovative SMEs, on the ground of their future growth opportunity and profitability. And also, we expect that the financial unconstrained firms can adjust dividend payment faster than the financial constrained firms, on the ground of their financing ability of investment funds through the market accessibility. Aivazian et al.(2006) exert that the financial unconstrained firms with the high accessibility to capital market can adjust dividend payment faster than the financial constrained firms. We collect the sample firms among the total SMEs listed on Korea Securities Market and Kosdaq Market of Korea Exchange during the periods from January 1999 to December 2007 from the KIS Value Library database. The total number of firm-year observations of the total sample firms throughout the entire period is 5,544, the number of firm-year observations of the dividend firms is 2,919, and the number of firm-year observations of the non-dividend firms is 2,625. About 53%(or 2,919) of these total 5,544 observations involve firms that make a dividend payment. The dividend firms are divided into two groups according to the R&D intensity, such as the innovative SMEs with larger than median of R&D intensity and the noninnovative SMEs with smaller than median of R&D intensity. The number of firm-year observations of the innovative SMEs is 1,506, and the number of firm-year observations of the noninnovative SMEs is 1,413. Furthermore, the innovative SMEs are divided into two groups according to level of financial constraints, such as the financial unconstrained firms and the financial constrained firms. The number of firm-year observations of the former is 894, and the number of firm-year observations of the latter is 612. Although all available firm-year observations of the dividend firms are collected, deletions are made in the case of financial industries such as banks, securities company, insurance company, and other financial services company, because their capital structure and business style are widely different from the general manufacturing firms. The stock repurchase was involved in dividend payment because Grullon and Michaely (2002) examined the substitution hypothesis between dividends and stock repurchases. However, our data structure is an unbalanced panel data since there is no requirement that the firm-year observations data are all available for each firms during the entire periods from January 1999 to December 2007 from the KIS Value Library database. We firstly estimate the classic Lintner(1956) dividend adjustment model, where the decision to smooth dividend or to adopt a residual dividend policy depends on financial constraints measured by market accessibility. Lintner model indicates that firms maintain stable and long run target payout ratio, and that firms adjust partially the gap between current payout rato and target payout ratio each year. In the Lintner model, dependent variable is the current dividend per share(DPSt), and independent variables are the past dividend per share(DPSt-1) and the current earnings per share(EPSt). We hypothesized that firms adjust partially the gap between the current dividend per share(DPSt) and the target payout ratio(Ω) each year, when the past dividend per share(DPSt-1) deviate from the target payout ratio(Ω). We secondly estimate the expansion model that extend the Lintner model by including the determinants suggested by the major theories of dividend, namely, residual dividend theory, dividend signaling theory, agency theory, catering theory, and transactions cost theory. In the expansion model, dependent variable is the current dividend per share(DPSt), explanatory variables are the past dividend per share(DPSt-1) and the current earnings per share(EPSt), and control variables are the current capital expenditure ratio(CEAt), the current leverage ratio(LEVt), the current operating return on assets(ROAt), the current business risk(RISKt), the current trading volume turnover ratio(TURNt), and the current dividend premium(DPREMt). In these control variables, CEAt, LEVt, and ROAt are the determinants suggested by the residual dividend theory and the agency theory, ROAt and RISKt are the determinants suggested by the dividend signaling theory, TURNt is the determinant suggested by the transactions cost theory, and DPREMt is the determinant suggested by the catering theory. Furthermore, we thirdly estimate the Lintner model and the expansion model by using the panel data of the financial unconstrained firms and the financial constrained firms, that are divided into two groups according to level of financial constraints. We expect that the financial unconstrained firms can adjust dividend payment faster than the financial constrained firms, because the former can finance more easily the investment funds through the market accessibility than the latter. We analyzed descriptive statistics such as mean, standard deviation, and median to delete the outliers from the panel data, conducted one way analysis of variance to check up the industry-specfic effects, and conducted difference test of firms characteristic variables between innovative SMEs and noninnovative SMEs as well as difference test of firms characteristic variables between financial unconstrained firms and financial constrained firms. We also conducted the correlation analysis and the variance inflation factors analysis to detect any multicollinearity among the independent variables. Both of the correlation coefficients and the variance inflation factors are roughly low to the extent that may be ignored the multicollinearity among the independent variables. Furthermore, we estimate both of the Lintner model and the expansion model using the panel regression analysis. We firstly test the time-specific effects and the firm-specific effects may be involved in our panel data through the Lagrange multiplier test that was proposed by Breusch and Pagan(1980), and secondly conduct Hausman test to prove that fixed effect model is fitter with our panel data than the random effect model. The main results of this study can be summarized as follows. The determinants suggested by the major theories of dividend, namely, residual dividend theory, dividend signaling theory, agency theory, catering theory, and transactions cost theory explain significantly the dividend policy of the innovative SMEs. Lintner model indicates that firms maintain stable and long run target payout ratio, and that firms adjust partially the gap between the current payout ratio and the target payout ratio each year. In the core variables of Lintner model, the past dividend per share has more effects to dividend smoothing than the current earnings per share. These results suggest that the innovative SMEs maintain stable and long run dividend policy which sustains the past dividend per share level without corporate special reasons. The main results show that dividend adjustment speed of the innovative SMEs is faster than that of the noninnovative SMEs. This means that the innovative SMEs with high level of R&D intensity can adjust dividend payment faster than the noninnovative SMEs, on the ground of their future growth opportunity and profitability. The other main results show that dividend adjustment speed of the financial unconstrained SMEs is faster than that of the financial constrained SMEs. This means that the financial unconstrained firms with high accessibility to capital market can adjust dividend payment faster than the financial constrained firms, on the ground of their financing ability of investment funds through the market accessibility. Futhermore, the other additional results show that dividend adjustment speed of the innovative SMEs classified by the Small and Medium Business Administration is faster than that of the unclassified SMEs. They are linked with various financial policies and services such as credit guaranteed service, policy fund for SMEs, venture investment fund, insurance program, and so on. In conclusion, the past dividend per share and the current earnings per share suggested by the Lintner model explain mainly dividend adjustment speed of the innovative SMEs, and also the financial constraints explain partially. Therefore, if managers can properly understand of the relations between financial constraints and dividend smoothing of innovative SMEs, they can maintain stable and long run dividend policy of the innovative SMEs through dividend smoothing. These are encouraging results for Korea government, that is, the Small and Medium Business Administration as it has implemented many policies to commit to the innovative SMEs. This paper may have a few limitations because it may be only early study about the relations between financial constraints and dividend smoothing of the innovative SMEs. Specifically, this paper may not adequately capture all of the subtle features of the innovative SMEs and the financial unconstrained SMEs. Therefore, we think that it is necessary to expand sample firms and control variables, and use more elaborate analysis methods in the future studies.
Land was originally communized by a community in the primitive society of Korea, and in the age of the ancient society SAM KUK-SILLA, KOKURYOE and PAEK JE-it was distributed under the principle of land-nationalization. But by the occupation of the lands which were permitted to transmit from generation to generation as Royal Grant Lands and newly cleared lands, the private occupation had already begun to be formed. Thus the private ownership of land originated by chiefs of the tribes had a trend to be gradually pervaded to the communal members. After the, SILLA Kingdom unified SAM KUK in 668 A.D., JEONG JEON System and KWAN RYO JEON System, which were the distribution systems of farmlands originated from the TANG Dynasty in China, were enforced to established the basis of an absolute monarchy. Even in this age the forest area was jointly controlled and commonly used by village communities because of the abundance of area and stocked volume, and the private ownership of the forest land was prohibited by law under the influence of the TANG Dynasty system. Toward the end of the SILLA Dynasty, however, as its centralism become weak, the tendency of the private occupancy of farmland by influential persons was expanded, and at the same time the occupancy of the forest land by the aristocrats and Buddhist temples began to come out. In the ensuing KORYO Dynasty (519 to 1391 A.D.) JEON SI KWA System under the principle of land-nationalization was strengthened and the privilege of tax collection was transferred to the bureaucrats and the aristocrats as a means of material compensation for them. Taking this opportunity the influential persons began to expand their lands for the tax collection on a large scale. Therefore, about in the middle of 11th century the farmlands and the forest lands were annexed not only around the vicinity of the capital but also in the border area by influential persons. Toward the end of the KORYO Dynasty the royal families, the bureaucrats and the local lords all possessed manors and occupied the forest lands on a large scale as a part of their farmlands. In the KORYO Dynasty, where national economic foundation was based upon the lands, the disorder of the land system threatened the fall of the Dynasty and so the land reform carried out by General YI SEONG-GYE had led to the creation of ensuing YI Dynasty. All systems of the YI Dynasty were substantially adopted from those of the KORYO Dynasty and thereby KWA JEON System was enforced under the principle of land-nationalization, while the occupancy or the forest land was strictly prohibited, except the national or royal uses, by the forbidden item in KYEONG JE YUK JEON SOK JEON, one of codes provided by the successive kings in the YI Dynasty. Thus the basis of the forest land system through the YI Dynasty had been established, while the private forest area possessed by influential persons since the previous KORYO Dynasty was preserved continuously under the influence of their authorities. Therefore, this principle of the prohibition was nothing but a legal fiction for the security of sovereign powers. Consequently the private occupancy of the forest area was gradually enlarged and finally toward the end of YI Dynasty the privately possessed forest lands were to be officially authorized. The forest administration systems in the YI Dynasty are summarized as follows: a) KEUM SAN and BONG SAN. Under the principle of land-nationalization by a powerful centralism KWA JEON System was established at the beginning of the YI Dynasty and its government expropriated all the forests and prohibited strictly the private occupation. In order to maintain the dignity of the royal capital, the forests surounding capital areas were instituted as KEUM SAN (the reserved forests) and the well-stocked natural forest lands were chosen throughout the nation by the government as BONG SAN(national forests for timber production), where the government nominated SAN JIK(forest rangers) and gave them duties to protect and afforest the forests. This forest reservation system exacted statute labors from the people of mountainious districts and yet their commons of the forest were restricted rigidly. This consequently aroused their strong aversion against such forest reservation, therefore those forest lands were radically spoiled by them. To settle this difficult problem successive kings emphasized the preservation of the forests repeatedly, and in KYEONG KUK DAI JOEN, the written constitution of the YI Dynasty, a regulation for the forest preservation was provided but the desired results could not be obtained. Subsequently the split of bureaucrats with incessant feuds among politicians and scholars weakened the centralism and moreover, the foreign invasions since 1592 made the national land devasted and the rural communities impoverished. It happned that many wandering peasants from rural areas moved into the deep forest lands, where they cultivated burnt fields recklessly in the reserved forest resulting in the severe damage of the national forests. And it was inevitable for the government to increase the number of BONG SAN in order to solve the problem of the timber shortage. The increase of its number accelerated illegal and reckless cutting inevitably by the people living mountainuos districts and so the government issued excessive laws and ordinances to reserve the forests. In the middle of the 18th century the severe feuds among the politicians being brought under control, the excessive laws and ordinances were put in good order and the political situation became temporarily stabilized. But in spite of those endeavors evil habitudes of forest devastation, which had been inveterate since the KORYO Dynasty, continued to become greater in degree. After the conclusion of "the Treaty of KANG WHA with Japan" in 1876 western administration system began to be adopted, and thereafter through the promulgation of the Forest Law in 1908 the Imperial Forests were separated from the National Forests and the modern forest ownership system was fixed. b) KANG MU JANG. After the reorganization of the military system, attaching importance to the Royal Guard Corps, the founder of the YI Dynasty, TAI JO (1392 to 1398 A.D.) instituted the royal preserves-KANG MU JANG-to attain the purposes for military training and royal hunting, prohibiting strictly private hunting, felling and clearing by the rural inhabitants. Moreover, the tyrant, YEON SAN (1495 to 1506 A.D.), expanded widely the preserves at random and strengthened its prohibition, so KANG MU JANG had become the focus of the public antipathy. Since the invasion of Japanese in 1592, however, the innovation of military training methods had to be made because of the changes of arms and tactics, and the royal preserves were laid aside consequently and finally they had become the private forests of influential persons since 17th century. c) Forests for official use. All the forests for official use occupied by government officies since the KORYO Dynasty were expropriated by the YI Dynasty in 1392, and afterwards the forests were allotted on a fixed standard area to the government officies in need of firewoods, and as the forest resources became exhausted due to the depredated forest yield, each office gradually enlarged the allotted area. In the 17th century the national land had been almost devastated by the Japanese invasion and therefore each office was in the difficulty with severe deficit in revenue, thereafter waste lands and forest lands were allotted to government offices inorder to promote the land clearing and the increase in the collections of taxes. And an abuse of wide occupation of the forests by them was derived and there appeared a cause of disorder in the forest land system. So a provision prohibiting to allot the forests newly official use was enacted in 1672, nevertheless the government offices were trying to enlarge their occupied area by encroaching the boundary and this abuse continued up to the end of the YI Dynasty. d) Private forests. The government, at the bigninning of the YI Dynasty, expropriated the forests all over the country under the principle of prohibition of private occupancy of forest lands except for the national uses, while it could not expropriate completely all of the forest lands privately occupied and inherited successively by bureaucrats, and even local governors could not control them because of their strong influences. Accordingly the King, TAI JONG (1401 to 1418 A.D.), legislated the prohibition of private forest occupancy in his code, KYEONG JE YUK JEON (1413), and furthermore he repeatedly emphasized to observe the law. But The private occupancy of forest lands was not yet ceased up at the age of the King, SE JO (1455 to 1468 A.D.), so he prescribed the provision in KYEONG KUK DAI JEON (1474), an immutable law as a written constitution in the YI Dynasty: "Anyone who privately occupy the forest land shall be inflicted 80 floggings" and he prohibited the private possession of forest area even by princes and princesses. But, it seemed to be almost impossible for only one provsion in a code to obstruct the historical growing tendecy of private forest occupancy, for example, the King, SEONG JONG (1470 to 1494 A.D.), himself granted the forests to his royal families in defiance of the prohibition and thereafter such precedents were successively expanded, and besides, taking advantage of these facts, the influential persons openly acquired their private forest lands. After tyrannical rule of the King, YEON SAN (1945 to 1506 A.D.), the political disorder due to the splits to bureaucrats with successional feuds and the usurpations of thrones accelerated the private forest occupancy in all parts of the country, thus the forbidden clause on the private forest occupancy in the law had become merely a legal fiction since the establishment of the Dynasty. As above mentioned, after the invasion of Japanese in 1592, the courts of princes (KUNG BANGG) fell into the financial difficulties, and successive kings transferred the right of tax collection from fisherys and saltfarms to each KUNG BANG and at the same time they allotted the forest areas in attempt to promote the clearing. Availing themselves of this opportunity, royal families and bureaucrats intended to occupy the forests on large scale. Besides a privilege of free selection of grave yard, which had been conventionalized from the era of the KORYO Dynasty, created an abuse of occuping too wide area for grave yards in any forest at their random, so the King, TAI JONG, restricted the area of grave yard and homestead of each family. Under the policy of suppresion of Buddhism in the YI Dynasty a privilege of taxexemption for Buddhist temples was deprived and temple forests had to follow the same course as private forests did. In the middle of 18th century the King, YEONG JO (1725 to 1776 A.D.), took an impartial policy for political parties and promoted the spirit of observing laws by putting royal orders and regulations in good order excessively issued before, thus the confused political situation was saved, meanwhile the government officially permittd the private forest ownership which substantially had already been permitted tacitly and at the same time the private afforestation areas around the grave yards was authorized as private forests at least within YONG HO (a boundary of grave yard). Consequently by the enforcement of above mentioned policies the forbidden clause of private forest ownership which had been a basic principle of forest system in the YI Dynasty entireely remained as only a historical document. Under the rule of the King, SUN JO (1801 to 1834 A.D.), the political situation again got into confusion and as the result of the exploitation from farmers by bureaucrats, the extremely impoverished rural communities created successively wandering peasants who cleared burnt fields and deforested recklessly. In this way the devastation of forests come to the peak regardless of being private forests or national forests, moreover, the influential persons extorted private forests or reserved forests and their expansion of grave yards became also excessive. In 1894 a regulation was issued that the extorted private forests shall be returned to the initial propriators and besides taking wide area of the grave yards was prohibited. And after a reform of the administrative structure following western style, a modern forest possession system was prepared in 1908 by the forest law including a regulation of the return system of forest land ownership. At this point a forbidden clause of private occupancy of forest land got abolished which had been kept even in fictitious state since the foundation of the YI Dynasty. e) Common forests. As above mentioned, the forest system in the YI Dynasty was on the ground of public ownership principle but there was a high restriction to the forest profits of farmers according to the progressive private possession of forest area. And the farmers realized the necessity of possessing common forest. They organized village associations, SONGE or KEUM SONGE, to take the ownerless forests remained around the village as the common forest in opposition to influential persons and on the other hand, they prepared the self-punishment system for the common management of their forests. They made a contribution to the forest protection by preserving the common forests in the late YI Dynasty. It is generally known that the absolute monarchy expr opriates the widespread common forests all over the country in the process of chainging from thefeudal society to the capitalistic one. At this turning point in Korea, Japanese colonialists made public that the ratio of national and private forest lands was 8 to 2 in the late YI Dynasty, but this was merely a distorted statistics with the intention of rationalizing of their dispossession of forests from Korean owners, and they took advantage of dead forbidden clause on the private occupancy of forests for their colonization. They were pretending as if all forests had been in ownerless state, but, in truth, almost all the forest lands in the late YI Dynasty except national forests were in the state of private ownership or private occupancy regardless of their lawfulness.