• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.202-217
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• 2022

Purpose: The recent increased use of Personal Mobility (PM) has been accompanied by a rise in the annual number of accidents. Accordingly, the safety requirements for PM use are being strengthened, but the laws/systems, infrastructure, and management systems remain insufficient for fostering a safe environment. Therefore, this study comprehensively searches the main problems and improvement methods through a review of previous studies that are related to PM. Then the priorities according to the importance of the improvement methods are presented through the Delphi survey. Method: The research method is mainly composed of a literature study and an expert survey (Delphi survey). Prior research and improvement cases (local governments, government departments, companies, etc.) are reviewed to derive problems and improvements, and a problem/improvement classification table is created based on keywords. Based on the classification contents, an expert survey is conducted to derive a priority improvement plan. Result: The PM-related problems were in 'non-compliance with traffic laws, lack of knowledge, inexperienced operation, and lack of safety awareness' in relation to human factors, and 'device characteristics, road-drivable space, road facilities, parking facilities' in relation to physical factors. 'Management/supervision, product management, user management, education/training' as administrative factors and legal factors are divided into 'absence/sufficiency of law, confusion/duplication, reduced effectiveness'. Improvement tasks related to this include 'PM education/public relations, parking/return, road improvement, PM registration/management, insurance, safety standards, traffic standards, PM device safety, PM supplementary facilities, enforcement/management, dedicated organization, service providers, management system, and related laws/institutional improvement', and 42 detailed tasks are derived for these 14 core tasks. The results for the importance evaluation of detailed tasks show that the tasks with a high overall average for the evaluation items of cost, time, effect, urgency, and feasibility were 'strengthening crackdown/instruction activities, education publicity/campaign, truancy PM management, and clarification of traffic rules'. Conclusion: The PM market is experiencing gradual growth based on shared services and a safe environment for PM use must be ensured along with industrial revitalization. In this respect, this study seeks out the major problems and improvement plans related to PM from a comprehensive point of view and prioritizes the necessary improvement measures. Therefore, it can serve as a basis of data for future policy establishment. In the future, in-depth data supplementation will be required for each key improvement area for practical policy application.

• Journal of Korean Elementary Science Education
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• v.41 no.4
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• pp.658-672
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• 2022

The unique teaching and learning difficulties of speed-related units in elementary school science are mainly due to the student's lack of mathematical thinking ability and procedural knowledge on speed measurement, and curriculums and textbooks must be constructed with these in mind. To identify the implications of composing a new science curriculum and relevant textbooks, this study reviewed the structure and contents of the speed-related units of three curriculums from the 2007 revised curriculum to the 2015 revised curriculum and the resulting textbooks and examined their relevance in light of the literature. Results showed that the current content carries the risk of making students calculate only the speed of an object through a mechanical algorithm by memorization rather than grasp the multifaceted relation between traveled distance, duration time, and speed. Findings also highlighted the need to reorganize the curriculum and textbooks to offer students the opportunity to learn the meaning of speed step-by-step by visualizing materials such as double number lines and dealing with simple numbers that are easy to calculate and understand intuitively. In addition, this paper discussed the urgency of improving inquiry performance such as process skills by observing and measuring an actual object's movement, displaying it as a graph, and interpreting it rather than conducting data interpretation through investigation. Lastly, although the current curriculum and textbooks emphasize the connection with daily life in their application aspects, they also deal with dynamics-related content somewhat differently from kinematics, which is the main learning content of the unit. Hence, it is necessary to reorganize the contents focusing on cases related to speed so that students can grasp the concept of speed and use it in their everyday lives. With regard to the new curriculum and textbooks, this study proposes that students be provided the opportunity to systematically and deeply study core topics rather than exclude content that is difficult to learn and challenging to teach so that students realize the value of science and enjoy learning it.

• Journal of the Daesoon Academy of Sciences
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• v.47
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• pp.1-37
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• 2023

This essay seeks to answer the question of how best to understand Korean new religious movements (KNRMs). KNRMs have the characteristics of folk religion, ethno-religion, or popular religion. KNRMs are products of the national consciousness promoted by Korean society during the Late Joseon Dynasty at the turning point of modern Yi-Jing Studies. From the perspective of social evolutionary theory of developmental history, during that period, Joseon (Korea), like China, was faced with a double-edged sword consisting of the strength of tradition and the upheaval of modernity. If the strength of tradition depended on the Yi-Jing Studies to promote national enlightenment toward anti-imperialist aims, then it was equally the case that modernity depended on the sense of urgency to guide the people to secure livelihoods and edification regarding anti-feudalism. In this essay, the KNRMs that appeared during this transition period of Yi-Jing Studies will be a significant focus, and the worldview of Daesoon Thought will be the main focus. As one of the central topics, intensive discussion will be dedicated to the issue of the nature of pre-experientialism (先驗主義) which characterized the Great Opening (開闢). The principles of Daesoon Thought have a religious dimension of realistic awareness that guides the people's lives and edifies them. The process of the Great Opening aims to secure an ontological clock that tracks the Great Itineration of the world toward Daesoon Truth. This in turn as a process establishes the epistemological world of the Reordering Works of Heaven and Earth (天地公事) and reaches the axiological boundary of the future world. The links among the Three Realms is characterized by a pre-experientialist line that experiences the space-time nature of the universe as the Great Opening of the Later World (後天) within the framework of Heaven and Earth. Throughout this course, humans look to enjoy the infinite vitality of the universe from within their own finite vitality. Therefore, Daesoon Thought can overcome perceived reality through pre-experientialist channels such as the Great Opening of the Later World and aim for a state of self-awareness such as the Earthly Paradise. This is an attempt to participate and practice in the actual world rather than pursuing a world of transcendental ideas, and therefore, it tends to be proactive in the world rather than exhibit a passive tendency to be worldliness. In conclusion, the truth of Daesoon Thought, which is characterized by the Great Opening of the Later World, contains a future-oriented outlook that longs for a Nextopia full of hope and promise rather than idealistic fancy towards a Utopia or well-founded dread and disdain towards Dystopia.

• Korean Journal of Construction Engineering and Management
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• v.25 no.2
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• pp.23-35
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• 2024

This study analyzed the correlation between each of the 12 influencing factors in FAR 16.04 and the decision-making process for construction contract types, using data from a total of 2,406 DoD Construction Acquisitions spanning from 2008 to 2022. The study considered 12 independent variables, grouped into 4 Characteristics with 3 factors each. Meanwhile, all other contract types were categorized into two types: Firm-Fixed-Price (FFP) and Cost-Reimbursement Contract (CRC), which served as the dependent variables. The findings revealed that FFP contracts significantly dominated in terms of acquisition volume. In line with prevailing beliefs, logistic data analysis and Analytical Hierarchy Process (AHP) analysis of Relative Weights from Experts' Survey demonstrated that independent variables like Uncertainty of the Scope of Work and Complexity found out to be increasing the likelihood of selecting CRC. The number of contractors in the market does indeed influence the possibilities of contract decision-making between CRC and FFP. Meanwhile, the p-values of the top 3 influencing factors on CRC from the AHP analysis-namely, Appropriateness of CAS, Project Urgency, and Cost Analysis-exceeded 0.05 in the binominal regression results, rendering it inconclusive whether they significantly influenced the construction contract type decision, particularly with respect to payment methods. This outcome partly results from the fact that a majority of respondents possessed specific experiences related to the USFK relocation project. Furthermore, influencing factors in construction projects behave differently than common beliefs suggest. As a result, it is imperative to consider the 12 influencing factors categorized into 4 Characteristics areas before establishing acquisition strategies for targeted construction projects.

• Journal of Technologic Dentistry
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• v.32 no.4
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• pp.417-433
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• 2010

Purpose: This study evaluated the manpower planning of dental technicians. Methods: Methods : Survey was conducted regarding subject's general characteristics, characteristics of dental technician's occupational view and working conditions, and reason to enter into branches of the public health enter. The survey sample consisted of 323 dental technicians (221 male/ 102 female). Survey was conducted for one month from August 1 to September 1 in 2010. Following results were obtained. Results: 1. Regarding general characteristics of the subjects, there was a slight male predilection with 68.4%. Subjects in their 40s occupied the highest proportion of 32.2%. Majority of subjects worked in the big cities (71.5%). Favored working places were dental laboratory (57.6%) and dental hospital or dental clinic (19.5%). Although no position is available in the public sector such as public health center or health care civil servant, 9.3% preferred working in the public health center. Public sector is more favored than 2-year technical colleges or dental supply and equipment companies. In respect to education, 57% of the subjects graduated college. 67.8% were married. Subjects who specialize in the porcelain or all-ceramic were 57.9%. With regard to current position, head of the dental laboratory was most common. 2. Following occupation characteristics were found. Economic reason took the highest proportion when deciding their occupation (39.9%) followed by gaining social experience (36.5%). Majority of the subjects (76.5%) wanted to work as dental technicians until their retirement. 71.5% pursuit to become a manager of the dental laboratory. 76.1% agreed on opening a dental technician position in the public health center. Regarding an authority to lead developing the dental technician position in the public sector, majority of the subject chose ministry of health and welfare (35.6%) and Korean dental technologist association (34.7%). Employment (average, 30%) and turnover rate (average, 36.5%) of dental technology college graduates ranged from 40% to 60%. Most important factors for the employment were practical experience (41.2%) and competency (34.4%). With regard to job satisfaction, so-so as 46.7% and satisfactory was 42.7% 3. In respect to the reason for opening a position in the public health center, 'It is needed to continue denture rogram for elderly patients' obtained the highest score (4.14 point). 'Institutional devices are required to open a position for dental technicians as a public healthcare provider' received high score (4.11 point). 4. Concerning the working conditions, 'professional knowledge is required' received the highest score (4.23) followed by 'too short maternity and parental leave' (4.21). 5. Relationship between general characteristics of the subjects and favor of working in the public health center was investigated. Significant differences were found according to the current and favored working area, favored occupation, education level, marital status, and specialty. Working in the public health center was favored by following subjects: working in mid- or small-sized cities (4.16 point, p<0.05); PhD degree-holder (4.59 point, p<0.01). 6. Among general characteristics of the subjects, significant difference of working conditions was found in the following factors: gender; working areas; favored working areas; favored working positions, and education level. Majority of subjects favored working in big cities and currently work in big cities although satisfaction was comparatively low (3.75 score). 7. Future plan to work in public health center was evaluated according to occupational characteristics. Subject's intention to work in the public healthcare center was significantly affected by opening of dental technician position, leading authority, average turnover rate, and factors affecting employment. Working in the public health care center was favored by the following subjects: Dental technicians who actively supported opening of the dental technician position (4.34 point, p<0.001); subjects who thought the Korean dental technologist association is responsible for the opening of positions in the public sector (4.26 point, p<0.001); and subjects who thought that attitude and character are important for the employment (p<0.001). 8. Concerning difference of working conditions according to the occupational characteristics, significant difference was demonstrated by factors such as a reason to choose to be a dental technician, work plan, pursuing position, responsible authority, average employment rate, and job satisfaction. High standard of working conditions was required in subjects who selected to be a dental technician for the leisure time after work (s.05 point, p<0.01), who planted to work until their marriage (4.25 point, p<0.001), and who pursuit to be a manager (3.98, p<0.05). 9. In respect to influence of general characteristics on the advancement to public health centers, the coefficient of determination (R2) was 0.068 and age affected the working condition with significant difference according to the pvalue. 10. Regarding influence of general characteristics on the advancement to public health centers, the coefficient of determination (R2) was 0.335 and work plan, opening of dental technician position in the public sector, and responsible authority had significant influence over the subject's intention to work in the public health center according to the p-value. 11. With regard to the influence of general characteristics on the advancement to public health centers, the coefficient of determination (R2) was 0.091 and reason to choose to be a dental technician, work plan, and responsible authority significantly affected subject's working conditions. Conclusion: Korean society is becoming a super-aged society according to several statistics. As aged population is rapidly increasing, national health insurance plans to cover denture for senior citizen over 75 years old from 2012. Therefore, dental technicians are urgently needed in the public health centers all over the nation. Many subjects in this study planed to work until their retirement and recognized dental technician's expertise. Ministry of health and welfare and Korean dental technologist association should co-operate each other to prepare foundation and institutional devices for dental technicians to advance into the public health center. This will improve oral health of the population. This study showed urgency of medical facilities and services which meets increasing number of aged population and welfare of the population.

• Journal of Chest Surgery
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• v.41 no.2
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• pp.210-215
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• 2008

Background: Drug-eluting stents are contributing to the exponential growth of percutaneous coronary intervention, and even in the patients with left main coronary artery disease, owing to the decreased restenosis rate. Our study aimed at comparing the one-year results after coronary artery bypass grafting versus percutaneous coronary intervention with drug-eluting stents in patients with left main coronary artery disease. Material and Method: Those patients who underwent coronary bypass surgery or stenting at our hospital under the diagnosis of left main coronary artery disease were divided in two groups. The variables for comparison were the preoperative disease severity, the length of the hospital stay, the early mortality and the cumulative incidence of mortality, myocardial infarction and repeated revascularization. Result: There were 101 cases in the surgery group and 78 cases in the stent group. Age, gender, the risk factors, the left ventricular ejection fraction and the proportion of acute coronary syndrome showed no significant differences between the two groups. The surgery group showed a more severe condition according to the Euroscore, a greater incidence of urgency, a longer hospital stay and a greater incidence of multi-vessel disease. The early mortality and one-year cumulative mortality were not different between the groups. The Euroscore-matched comparison for the surgery group (41 patients) and the stent group (78 patients) showed no significant differences in the Euroscore, age, gender, risk factors and the proportion of acute coronary syndrome. The surgery group in the Euroscore-matched comparison showed more multi-vessel disease and a longer hospital stay. The surgery group showed lower early mortality and lower one-year cumulative mortality, but this was statistically insignificant (0% vs 2.6%, respectively, p=0.55; 0% vs 6.6%, respectively, p=0.30). The rates of repeated revascularization and major adverse events (death or myocardial infarct) were lower in the CABG group, but this was not statistically significant (13.3% vs 6.3%, respectively, p=0.48; 10.0% vs 0%, respectively, p=0.09). Conclusion: Percutaneous coronary intervention using drug-eluting stents in low-risk patients with left main coronary artery disease resulted in a shortened length of the hospital stay, as compared with that of the CABG group of patients. However, the patients who underwent percutaneous coronary intervention using drug-eluting stents showed a tendency for an increased rate of repeated revascularization and higher one-year cumulative mortality. Further studies with large populations and longer follow-up will be necessary to reaffirm our findings.

• The Korean Journal of Air & Space Law and Policy
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• v.24 no.1
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• pp.35-58
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• 2009

A treaty that governs the compensation on damage caused by aircraft to the third parties on surface was first adopted in Rome in 1933, but without support from the international aviation community it was replaced by another convention adopted again in Rome in 1952. Despite the increase of the compensation amount and some improvements to the old version, the Rome Convention 1952 with 49 State parties as of today is not considered universally accepted. Neither is the Montreal Protocol 1978 amending the Rome Convention 1952, with only 12 State parties excluding major aviation powers like USA, Japan, UK, and Germany. Consequently, it is mostly the local laws that apply to the compensation case of surface damage caused by the aircraft, contrary to the intention of those countries and people who involved themselves in the drafting of the early conventions on surface damage. The terrorist attacks 9/11 proved that even the strongest power in the world like the USA cannot with ease bear all the damages done to the third parties by the terrorist acts involving aircraft. Accordingly as a matter of urgency, the International Civil Aviation Organization(ICAO) picked up the matter and have it considered among member States for a few years through its Legal Committee before proposing for adoption as a new treaty in the Diplomatic Conference held in Montreal, Canada 20 April to 2 May 2009. Accordingly, two treaties based on the drafts of the Legal Committee were adopted in Montreal by consensus, one on the compensation for general risk damage caused by aircraft, the other one on compensation for damage from acts of unlawful interference involving aircraft. Both Conventions improved the old Convention/Protocol in many aspects. Deleting 'surface' in defining the damage to the third parties in the title and contents of the Conventions is the first improvement because the third party damage is not necessarily limited to surface on the soil and sea of the Earth. Thus Mid-air collision is now the new scope of application. Increasing compensation limit in big gallop is another improvement, so is the inclusion of the mental injury accompanied by bodily injury as the damage to be compensated. In fact, jurisprudence in recent years for cases of passengers in aircraft accident holds aircraft operators to be liable to such mental injuries. However, "Terror Convention" involving unlawful interference of aircraft has some unique provisions of innovation and others. While establishing the International Civil Aviation Compensation Fund to supplement, when necessary, the damages that exceed the limit to be covered by aircraft operators through insurance taking is an innovation, leaving the fate of the Convention to a State Party, implying in fact the USA, is harming its universality. Furthermore, taking into account the fact that the damage incurred by the terrorist acts, where ever it takes place targeting whichever sector or industry, are the domain of the State responsibility, imposing the burden of compensation resulting from terrorist acts in the air industry on the aircraft operators and passengers/shippers is a source of serious concern for the prospect of the Convention. This is more so when the risks of terrorist acts normally aimed at a few countries because of current international political situation are spread out to many innocent countries without quid pro quo.

• The Korean Journal of Air & Space Law and Policy
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• v.29 no.1
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• pp.127-160
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• 2014

The UN COPUOS was established in 1959 as a permanent committee of the UN General Assembly with the aims to promote international cooperation in peaceful uses of outer space, to formulate space-related programmes within the UN, to encourage research and dissemination of information on space, and to study legal problems arising from the outer space activities. Its members have been enlarged from 24 members in 1959 to 76 in 2014. The Legal Subcommittee, which has been established under COPUOS in 1962 to deal with legal problems associated with space activities, through its first three decades of work has set up a framework of international space law: the five treaties and agreements - namely the Outer Space Treaty, Rescue Agreement, Liability Convention, Registration Convention, Moon Agreement - and the five declarations and legal principles. However, some sceptical views on this legal framework has been expressed, concerning the applicability of existing international space law to practical issues and new kinds of emerging space activities. UNISPACE III, which took place in 1999, served as a momentum to revitalize the discussions of the legal issues faced by the international community in outer space activities. The agenda of the Legal Subcommittee is currently structured into three categories: regular items, single issue/items, and items considered under a multi-year workplan. The regular items, which deal with basic legal issues, include definition and delimitation of outer space, status and application of the five UN treaties on outer space, and national legislation relevant to the peaceful exploration and use of outer space. The single issues/items, which are decided upon the preceding year, are discussed only for one year in the plenary unless renewed. They include items related to the use of nuclear power sources in outer space and to the space debris mitigation. The agenda items considered under a multi-year work plan are discussed in working group. Items under this category deal with non-legally binding UN instruments on outer space and international mechanism for cooperation. In recent years, the Subcommittee has made some progress on agenda items related to nuclear power sources, space debris, and international cooperation by means of establishing non-legally binding instruments, or soft law. The Republic of Korea became the member state of COPUOS in 2001, after rotating seats every two years with Cuba and Peru since 1994. Korea's joining of COPUOS seems to be late, in considering that some countries with hardly any space activity, such Chad, Sierra Leone, Kenya, Lebanon, Cameroon, joined COPUOS as early as 1960s and 1970s and contributed to the drafting of the aforementioned treaties, declarations, and legal principles. Given the difficulties to conclude a treaty and un urgency to regulate newly emerging space activities, Legal Subcommittee now focuses its effort on developing soft law such as resolutions and guideline to be adopted by UN General Assembly. In order to have its own practices reflected in the international practices, one of the constituent elements of international customary law, Korea should analyse its technical capability, policy, and law related to outer space activities and participate actively in the formation process of the soft law.

• Korean Journal of Heritage: History & Science
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• v.52 no.2
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• pp.80-105
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• 2019

With the increasing complexity and irregularity of disaster types, the need for cultural asset preservation and management from a proactive perspective has increased as a number of cultural properties have been destroyed and damaged by various natural and humanistic factors. In consideration of these circumstances, the Cultural Heritage Administration enacted an Act in December 2005 to enforce the regular commission of surveys for the systematic preservation and management of cultural assets, and through a recent revision of this Act, the investigation cycle has been reduced from five to three years, and the object of regular inspections has been expanded to cover registered cultural properties. According to the ordinance, a periodic survey of city- or province-designated heritage is to be carried out mainly by metropolitan and provincial governments. The Seoul Metropolitan Government prepared a legal basis for commissioning regular surveys under the Seoul Special City Cultural Properties Protection Ordinance 2008 and, in recognition of the importance of preventive management due to the large number of cultural assets located in the city center and the high demand for visits, conducted regular surveys of the entire city-designated cultural assets from 2016 to 2018. Upon the first survey being completed, it was considered necessary to review the policy effectiveness of the system and to conduct a comprehensive review of the results of the regular surveys that had been carried out to enhance the management of cultural assets. Therefore, the present study examined the comprehensive management status of the cultural assets designated by the Seoul Metropolitan Government for three years (2016-2018), assessing the performance and identifying limitations. Additionally, ways to improve it were sought, and a DB establishment plan for the establishment of an integrated management system under the auspices of the Seoul Metropolitan Government was proposed. Specifically, survey forms were administered under the Guidelines for the Operation of Periodic Surveys of National Designated Cultural Assets; however, the types of survey forms were reclassified and further subdivided in consideration of the characteristics of the designated cultural assets, and manuals were developed for consistent and specific information technologies in respect of the scope and manner of the survey. Based on this analysis, it was confirmed that 401 cases (77.0%) out of 521 cases were generally well preserved; however, 102 cases (19.6%) were found to require special measures such as attention, precision diagnosis, and repair. Meanwhile, there were 18 cases (3.4%) of unsurveyed cultural assets. These were inaccessible to the investigation at this time due to reasons such as unknown location or closure to the public. Regarding the specific types of cultural assets, among a total of 171 cultural real estate properties, 63 cases (36.8%) of structural damage were caused by the failure and elimination of members, and 73 cases (42.7%) of surface area damage were the result of biological damage. Almost all plants and geological earth and scenic spots were well preserved. In the case of movable cultural assets, 25 cases (7.1%) among 350 cases were found to have changed location, and structural damage and surface area damage was found according to specific material properties, excluding ceramics. In particular, papers, textiles, and leather goods, with material properties that are vulnerable to damage, were found to have greater damage than those of other materials because they were owned and managed by individuals and temples. Thus, it has been confirmed that more proactive management is needed. Accordingly, an action plan for the comprehensive preservation and management status check shall be developed according to management status and urgency, and the project promotion plan and the focus management target should be selected and managed first. In particular, concerning movable cultural assets, there have been some cases in which new locations have gone unreported after changes in ownership (management); therefore, a new system is required to strengthen the obligation to report changes in ownership (management) or location. Based on the current status diagnosis and improvement measures, it is expected that the foundation of a proactive and efficient cultural asset management system can be realized through the establishment of an effective mid- to long-term database of the integrated management system pursued by the Seoul Metropolitan Government.

• Korean Journal of Heritage: History & Science
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• v.56 no.4
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• pp.230-246
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• 2023

The wooden fence(木柵), which began to appear in the Bronze Age and is presumed to be the oldest defense facility in human history, was used as a fortress for the purpose of further strengthening military defense functions until after the Japanese Invasion of Korea in 1592 in the Joseon Dynasty(壬辰倭亂). As it was established as the concept of a fortress or a fence installed outside a fence castle(城柵) or barracks fence(營柵), its importance as an essential facility for defense was further highlighted. This study is the result of exploring wooden fence that were used as official facilities during the Joseon Dynasty, focusing on literature surveys such as 『Annals of the Joseon Dynasty』 and 『New Jeungdonggukyeojiseungram』 In this study, in particular, the conclusion of this study is as follows, focusing on the use and function of Nokgakseong(鹿角城), underwater wooden fence, installation methods, and materials of wooden fences, is as follows. The conclusions of this study, which focused on the materials of the wooden fence, are as follows. First, as invasions by foreign enemies became more frequent in the late Goryeo and early Joseon Dynasty, wooden fences played a major role as a major out-of-castle defense facility((防禦施設). In addition, wooden fences were modified and installed into various types such as wooden fences(木柵城), Nokgakseong, a fence made up of large branches in the shape of a deer antler, and underwater wooden fences(水中木柵) according to the circumstances of the times, government policy, and location environment. Second, wooden fences were installed in strategic locations in defense facilities for military purposes, such as mountain fortress(山城), fortresses(營), camps(鎭), forts(堡), and castles(邑城) in strategic locations, and were used for defense in case of emergency. According to the urgency of farming, it was installed in accordance with the non-farming season, when it is easy to mobilize manpower to avoid the busy farming season. The size of the wooden fence of the Joseon Dynasty, which are confirmed through literature records, was converted into Pobaekchuk(布帛尺), and the circumference was very diverse from 4,428chuk(2,066m) to 55chuk(25m). Third, Nokgakseong is an efficient combat support facility that is more aggressive than a general wooden fence, and the records of Nokgakseong in the Annals of the Joseon Dynasty appeared during the King Sejong period the record was 20 times, the most. By region, it was found that it was mainly installed in coastal rugged areas such as Pyeongan and Hamgildo(12), which are the 6-jin areas of the 4th Army. Fourth, in the early 15th century, as the royal court established a maritime defense strategy for the coastal area of the southern coast, after the Sampo Invasion(三浦倭亂), riots by Japanese settlers in Sampo in 1510, major military posts including eupseong(邑城), camps, and forts were established. The installation of underwater barriers around various government facilities rapidly increased as a defense facility to block the warships of Japanese pirates around various government facilities. Fifth, between the 15th and 17th centuries before and after the Japanese Invasion of Korea in Sampo, underwater fences were installed in the Southern coast and Ganghwa Island. In particular, in the 15th century, underwater fences were intensively installed in coastal areas of Gyeongsangnam-do, such as Jepo. Pine trees and Oaks are the main materials used for underwater fences, but other materials such as Oldham's meliosma, Loose-flower hornbeam and The vines of arrowroots were also used as materials for wooden fences.