• Title/Summary/Keyword: Settlement System

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An Evaluation of Solid Removal Efficiency in Coagulation System for Treating Combined Sewer Overflows by Return Sludge (CSOs처리를 위한 응집침전시스템에서 슬러지 반송에 의한 고형물 처리효율평가)

  • Ha, Sung-Ryong;Lee, Seung-Chul
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.3
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    • pp.171-178
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    • 2013
  • In this study, the sludge that occurs in the initial operation of coagulation system developed for the treatment of CSOs were returned to the flocculation reactor. The purposes of this study were to analyze the Characteristics of flocs that are generated through the recycling sludge and settling characteristics of sludge, and to evaluate the possibility that high concentrations of particulate matter in the initial inflow of CSOs could be used as an weighted coagulant additive. As a result, the concentration of treated CSOs pollutants at the beginning of the CSOs influent with a large amount of particulate matter over 20 ${\mu}m$ was low, after gradually increasing the concentrations of them. The flocs generated from the sludge return were similar in size compared to flocs generated through injection of micro sands, and settling velocity in case of return sludge injection was decreased from 55.1 cm/min to 21.5 cm/min. SVI value of the sludge accumulated at the bottom of the sedimentation tank was 72, and settled sludge volume decreased rapidly due to the consolidation of sludge to the time it takes to 10 minutes. these mean that sludge used for recycling has good settling characteristic. A condition of returned sludge which is 0.1% return of 0.3% extraction was formed in the balance of settlement and extraction. In this case, This condition was to be adequate to maintain the proper concentration such as 100~200 mg/L of TS and 50~100 mg/L of VS in the flocculation reactor. The usage of the return sludge containing particulate matters of CSOs as an weighted coagulant additive was able to secure a stable treated water quality despite the change of influent water quality dynamically. Furthermore, it can be expected to reduce the alum dosage along with the sludge production.

A comparative study between Korea and the USA on the development process in retail trade & its changing locations (소매업의 발달과정과 입지 변화에 관한 한.미 비교 연구)

  • Jeon, Kyung-Sook
    • Journal of the Korean association of regional geographers
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    • v.6 no.2
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    • pp.21-40
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    • 2000
  • The retail trades in many countries have changed recently according to the high quality, diversification, and marked individuality of consumer needs. Under the continually competing system of the WTO agreement, corporations based in the USA and the EU try to raise their market share in other countries so it is inevitable for Korean retail enterprises to compete with them. This paper is aimed at contributing to the efficient growth for Korean retail trade from the analysis of the development process in retail trade and its changing locations comparing Korea and the USA. Retailers in the USA have practiced diversified marketing strategies considerably in order to survive in a rapidly changing retailing environment. American retailing, which has the most advanced marketing system in the world, has been of growing concern to marketing strategies in Korea. The following is a brief summary of this study. 1. Speedy and higher quality consumption is needed in accordance with the great increase in the single-family household and the female labor force participation both in Korea and in the USA. Senior citizens have become a new consumer group due to the aging population. In the future the retail trade will switch over to diversified retail formats and internet shopping as countries are transformed into information and communication societies. 2. In Korea, the former retail system characterized by markets and department stores has been greatly changed since the late 1980s with emphasis on high quality and convenience in consumption behaviors, with large domestic enterprises and foreign distribution corporations participating in Korean retailing. In the USA, retailing mergers and takeovers by major retails, bankruptcies, and extra-large shopping centers have emerged since the late 1980s. Recently, the USA retailing formats have been changed from the lower price-oriented discount types to the large scale theme parks. Much emphasis was put on entertainment, resorts, and convention centers. On the other hand, non-store types, such as the internet shopping, the CATV shopping, as well as catalog and mail-order sales are drastically increasing, although the proportion of their sales is low up to now. 3. In Korea, most of the retail facilities are concentrated in Seoul and the Metropolitan Region, and the distribution ratio of facilities came to 52% in 1997. The periodic markets, traditional markets which open on a periodic basis, are located mainly in Chollanam-do and Kyungsangbuk-do. The large-sized discount stores have expanded their locations to the over-crowded apartment complexes in new towns, located in the Metropolitan Region, and the large provincial cities, unlike the suburban locations in the USA. Therefore we needed to give attention to the locational relations in retail facilities between Seoul & the Metropolitan Region and rural settlement areas. In the USA, urban areas grew quickly with the development of the automobile in the 1920s, and the location of stores changed from a dispersed style centering around rural areas to a centralized one in urban areas. There is an accelerated growth for suburban areas, which have grown rapidly since 1950. As the membership warehouse clubs were introduced in the 1970s, the decentralization of location was more intensified. On the other hand, inner cities were revitalized by rearranging existing facilities to cope with suburban areas. And the location-free virtual retailing & TV shopping are also growing every year. 4. In view of the above, the continuous and desirable development devices in Korean retail trade are summarized as follows: First, the countermeasures against economies of scale, increase in retailing sales, and rise of a employment percentage in retailing are in need. Second, a scheme of lowering the proportion of food retail sales, and increasing a ratio of durable goods sales need to be worked out. Third, the original ideas are needed to apply positively information, communication and technology to retailing, to graft the traditional types on modem ones based on the social culture. Fourth, strategies are needed to strengthen the competitiveness of our retail trade through cooperation and chains of smaller retailers, the large enterprises participating in the distribution industry. Fifth, in order to realize the above, the retail industry, the administration, and the academic world should support the retail segment with concern and a practical strategy plan.

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A Comparative Study on the Principal Tasks for State Building and the Presidents of Korea and the Philippines: Syngman Rhee with Manuel Quezon and others (한국과 필리핀 건국의 핵심 과제와 대통령(들) 비교: 이승만 대 케손 등)

  • LEW, Seok Choon;CHO, Jung Ki
    • The Southeast Asian review
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    • v.27 no.1
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    • pp.1-52
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    • 2017
  • This study aims to compare the state building process focusing on the founding presidents of South Korea, which was a colony of the defeated state of World War II and the Philippines, the colony of the victorious state. To this end, it compares the lives of the presidents, mainly the founding president of Korea Syngman Rhee and Manuel Quezon who led the autonomy of the Philippines and established the Commonwealth government, in the contexts of the state building process of the two countries. In each country, the leaders had to address the core tasks for founding the states in common. Firstly, after the independence or the acquisition of state autonomy, both countries adopted a constitution based on the presidential system with the strong authority of the presidents influenced by the United States. Secondly, the two countries after the independence were operated on the basis of anti-communism at the forefront of the Cold War. In addition, they also carried out land reform to bring the peasants into the system for supporting anti-communism. Lastly, the two countries also faced the same issues of liquidating the Japanese colonial legacies. Therefore the study examines the establishment of the constitution, settlement of anti-communism line, the land reform issues, and liquidation of Japanese colonialism or occupation in each country. The Philippines attained 'constitutional independence' in 1935 and experienced political development faster than any other post-colonial country in Asia. However, except for the establishment of the constitution, the early leaders were not able to address the principal issues for state building. As land reform failed, landowners became economically and politically dominant. The Philippines, where the modern citizen class has not arisen suffered from the political and economic recession. In Korea, despite the Korean War and division of the country, the founding president Syngman Rhee attempted to solve the tasks. As a result, he was able to lay the track of liberal democracy against communism and also settled Japanese colonial legacy as much as it was allowed. In particular, through land reform, he has laid the basis for the nation-state and economic development and has set up the girders of Korean economy by adopting the market economy system. Although there are merits and demerits, compared with the leaders of other countries especially with the Philippines, it is no doubt that Syngman Rhee has played an essential role in establishing the state as a founding president.

Awareness, need and demand for the amendment of medical device law according to the general characteristics of some dental hygienists (일부 치과위생사들의 일반적 특성에 따른 의료기사법 개정에 대한 인식, 필요 및 요구도)

  • Lee, Hyeon-Jeong;Kwak, Ji-Won;Lee, Dong-Ha;Lee, Hyeon-Hee;Jeong, Hae-Mi;Joo, Soo-Yeon;Seong, Mi-Gyung
    • Journal of Korean Dental Hygiene Science
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    • v.1 no.1
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    • pp.23-36
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    • 2018
  • This research has been conducted from June 1, 2017 to August 25, 2017 for the dental hygienists working in Busan and Gyeongnam area, to provide necessary basic data for the purpose of revision of the relating laws from the analysis of their understanding and perspective on such laws through 262 subjects' questionnaire. Its analysis of their perspectives are as follows. 1. The common characteristics of the subjects are that 40.1% of them are under 25, and their working period was under three years with the 38.9%, and as for their marital status, 70.2% were single, the final education of 80.2% were associated degrees. Their working areas are centered in Gyeongsangnam-do province with 91.2%, the workplace type is for the dental clinic with 80.2%. 2. The comparison of the view point of the medical(technician) law according to the characteristics of the research subjects differed only whether or not the completion of the education, and as a result of the comparison according to the characteristics of those subjects understanding the details of the medical(technician) law, there was a significant difference saying "the current law has clear job description" depending on the working area or "the job duty is definite" depending on the job experience and job details. As for those saying "the job duty is definite", there was also significant difference depending upon marital status, final education and work details. There was no significant difference in all characteristics from findings of the necessity of legal system according to the subjects not understanding the medical(technician) law. 3. As a result of comparing the necessity of the medical(technician) law according to the characteristics of the research subjects, it was found that all the subjects accepted the necessity of the medical law revision including the dental hygienist in the medical person. The "necessity of the professional dental hygienist system" showed a significant difference depending upon the final education and medical institution type. Among the triggering factors in its amendment, there showed significant difference in the "cooperation of other organizations" and "solution of medical law problems" only in the final education. 4. As a result of comparison of the needs of the medical(technician) law revision according to the characteristics of the research subjects, it was found that the significant traits related to the age and job details showed "Legal responsibility would be increased" when the medical law is revised, in case that "it will help broaden the job extension", there showed a significant difference in career, final education, and working institution, and job details. "Legal protection is possible" showed significant difference except the age group and working area, and "it help the system settlement" showed in the final education. There was a significant difference in career, final education, and job details that "I can regulate the education and field practice", and the same in "my status will be improved" depending upon the final education, work area, and job details. Accordingly, in this research, for the establishment of more professional and comprehensive dental health service as suggested from the demand and necessity toward the medical(technician) Law by the dental hygienists.

The Improvement Measurement on Dispute Resolution System for Air Service Customer (항공서비스 소비자 분쟁해결제도의 개선방안)

  • Lee, Kang-Bin
    • The Korean Journal of Air & Space Law and Policy
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    • v.33 no.2
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    • pp.225-266
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    • 2018
  • In 2017, 1,252 cases of damages relief related to air passenger transport service were received by the Korea Consumer Agency, a 0.8% drop from 1,262 cases in 2016, the first decline since 2013. In 2017, 444 cases (35.4%) out of received cases of damages relief in the field of air passenger service received by the Korea Consumer Agency were agreed on, and out of cases that were not agreed on, the most number of 588 cases (47.0%) were concluded due to information provision and counseling, and 186 cases (14.9%) were applied to the mediation of the Consumer Dispute Mediation Committee. Major legislations that contain regulations for the damages relief and disputes resolution of air service consumers include the Aviation Business Act and the Consumer Fundamental Act, etc. The Aviation Business Act provides the establishment and implementation of damage relief procedure and handling plan, and the receiving and handling of request of damage relief by air transport businessman, and the notice of protection standard for air traffic users. The Consumer Fundamental Act provides the establishment and management of the consumer counseling organization, the damage relief by the Korea Consumer Agency, the consumer dispute mediation, and the enactment of the criteria for resolving consumer disputes. The procedures for damages relief of air service consumers include the receiving and handling of damages relief by air transport businessman, the counseling, and receiving and handling of damages relief by the Consumer Counseling Center, the advice of mutual agreement by the Korea Consumer Agency, and the dispute mediation system by the Consumer Dispute Mediation Committee. The current system of damage relief and dispute mediation for air service consumer have the problem in the exemption from obligation of establishment and implementation of damage relief plan by air transport businessman under the Aviation Business Act, the problem in the exemption from liability in case of nonfulfillment and delay of transport by aviation businessman under the criteria for resolving consumer disputes in the aviation sector, and the uppermost limit in procedure progress and completion of consumer dispute mediation under the Consumer Fundamental Act. Therefore, the improvement measurements of the relevant system for proper damage relief and smooth dispute mediation for air service consumer are to be suggested as follows: First is the maintenance of the relevant laws for damage relief of air service consumer. The exemption regulation from obligation of establishment and implementation of damage relief plan by air transport businessman under the Aviation Business Act shall be revised. To enhance the structualization and expertise of the relevant regulation for protection and damage relief of air service consumer, it will be necessary to prepare the separate legislation similar to the US Federal Regulation 14 CFR and EU Regulation EC Regulation 261/2004. Second is the improvement of criteria for resolving air service consumer disputes. For this, it will be necessary to investigate whether the cause of occurrence of exemption reason was force majeure, and distinguish the exemption from liability in case of nonfulfillment and delay of transport by aviation businessman under the criteria for resolving consumer disputes in the aviation sector, and revise the same as exemption reasons regulated under the air transport chapter of the Commercial Act and Montreal Convention 1999, and unify the compensation criteria for the nonfulfillment of transport that the substitute flight was provided and the delay of transport. Third is the reinforcement of information provision for damage relief of air service consumer. Aviation-related government agencies and concerned agencies should cooperate with airlines and airports to provide rapidly and clearly diverse information to the air traffic users, including laws and policies for damages relief of air service consumers. Fourth is the supplement to the effectiveness, etc. of consumer dispute mediation. If there is no sign of acceptance for dispute mediation, it is not fair to regard it as acceptance, therefore it will be necessary to add objection system. And if a dispute resolution is requested to another dispute settlement agency in addition to the Consumer Dispute Mediation Committee, it is excluded from the damage relief package, but it should be allowed for the party to choose a mediation agency. It will be necessary to devise the institutional measures to increase the completion rate of mediation so that the consumer dispute can be resolved efficiently through the mediation. Fifth is the introduction of the air service consumer arbitration system. A measure to supplement the limitations of the consumer dispute mediation system is to introduce the consumer arbitration system, but there are two measurements which are the introduction of the consumer arbitration under the Consumer Fundamental Act and the introduction of the consumer arbitration under the Arbitration Act. The latter measurement is considered to be appropriate. In conclusion, as a policy task, the government should prepare laws and system to enhance the prevention and relief of damages and protection of the rights and interests of air service consumers, and establish and implement the consumer-centric policy for the advancement of air service.

A Study on Improvement Examination Standard for the Limit of changing Current State of the Cultural Properties (문화재 유형별 현상변경 검토기준 마련 연구)

  • Cho, Hong-Seok;Park, Hyun-Joon;Lee, You-Beom;Lee, Cheon-Woo;Kim, Chul-Ju;Park, Jung-Seop;Kim, Sang-Dong
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.33 no.4
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    • pp.148-165
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    • 2015
  • The Cultural Properties Protection Law Act 1962 has been achieving its role for systematic preservation, management and application of the cultural heritage under rapid economic growth circumstances through continuing revisions. Introduced the influence review system for cultural heritages in 2000, and legislated the guideline for the state-change allowance standard for the National Cultural Heritage in 2006 in specific, the law has been contributing significantly for the cultural properties and historical/cultural environment preservation, along with increase in administrative efficiency and improvement on settlement environment. However, increase in public awareness about the cultural property's value and the needs for the local revitalization by utilizing the heritages, while some allowance standard not peoperly delivering the surrounding conditions, such as the value of the properties and their substantial characteristics, land utilization, etc. being applied, complaints from the local residents are increasing continuously. Thus this research focuses on clear vision/value of the heritage and apply them to create the review criteria for the state-change allowance per heritages. Here we set the Focus of Landscape Management Indicators in order to actively preserve and manage the physical characteristics and the native value by analyzing the Cultural Heritage Protection Laws and related guidelines, manuals and research papers, and redesign the cultural propertiy's classification scheme and propose the Review Standard for state-change from the view point of changing the current state. With this research, we expect increase in the satisfaction for the Property management system with public understanding promotion regarding the Standards by applying the reviewed state-change allowance Standards, white securing the consistency for the review criteria as well as the systematic management of historical/cultural environment with their typification characteristics and the value for short-term.

Influence of bearing surface angle of abutment screw on mechanical stability of joint in the conical seal design implant system (내부 원추형 연결형태 임플란트에서 지대주 나사머리의 좌면각도가 연결부 기계적 안정성에 미치는 영향)

  • Kim, Joo-Hyeun;Huh, Jung-Bo;Yun, Mi-Jung;Kang, Eun-Sook;Heo, Jae-Chan;Jeong, Chang-Mo
    • Journal of Dental Rehabilitation and Applied Science
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    • v.30 no.3
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    • pp.206-214
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    • 2014
  • This study is to evaluate how different bearing surface angles of abutment screw affect the mechanical stability of the joint in the conical seal design implant system. Materials and Methods: Internal connection type regular implants, two-piece cemented type abutments and tungsten carbide/carbon-coated titanium alloy abutment screws were selected. Titanium alloy screws with conical ($45^{\circ}$) and flat ($90^{\circ}$) head designs which fit on to abutment were fabricated. The abutments were tightened to implants with 30 Ncm by digital torque gauge. The loading was applied once to the central axis of abutment. The mean axial displacement was measured using micrometer before and after the tightening and loading (n = 5). The abutment was tightened to implants with 30 Ncm and T-shape stainless steel crown was cemented. Then the change in the amount of reverse-torque was measured after the repeated loading to the central axis, and the place 5 mm away from the central axis. Compressive bending and fatigue strength were measured at the place 5 mm away from the central axis (n = 5). Results: Both groups showed the largest axial displacement when abutment screw tightening and total displacement was greater in the flat head group compared to conical head group (P < 0.05). However, there were no significant differences in reverse torque value, compressive bending and fatigue strength (P > 0.05). Conclusion: Within the limitations of this study, the abutment screw head design had no effect on two groups regarding the joint stability, however the conical head design affected the settlement of abutment resulting in the reduced total displacement.

Performance of Occupational Health Services by Type of Service : Cost Benefit Analysis (사업장 보건관리 사업의 형태별 수행성과 분석 -비용편익 분석을 중심으로-)

  • Cho, Tong Ran;Kim, Hwa Joong
    • Korean Journal of Occupational Health Nursing
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    • v.4
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    • pp.5-29
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    • 1995
  • Occupational health services in Korea have been operated as dual types : one is operated by occupational health care manager and the other is health care agency without their own personnel. The performance of occupational health service should be different due to the variety of characteristics of health care manager and workplace, qualification of health care manager. This study is to analyze performance of occupational health care services with a particular consideration of job performance shape and efficiency, based on comparing those two types of health care management to show on the basic data for the settlement of more qualitative health care management system at workplace. For this study, total 391 places in Seoul and Inchon city area ; 154 places (39.4%) managed by designated health care manager and 237 places (60.6%) by the agency with their commission are selected as research samples. Tools for data collection are questionnares that have been investigated during the period of 20 September 1993-20 December 1993. Those data are compared with percentiles, mean, standard deviation and B/C ratio using SPSS PC program. Conclusions observed from the tests and each comparison could be summerized as follows : 1. Occupational health care have been accomplished at workplaces with designated people than with agencies people, and coverage rate of the occupational health care services has differences, due to management types. The reason of these results is due to visit only one or two times monthly by the agencies, while their own health care manager obsess, at the workplaces all the times. 2. Most of the expense for environmental control of all health care services expenditures shows that there is almost no fundamental improvement because more expenses are needed for procuring personal protective equipment and measuring work environment instead of environmental improvement. 3. It is investigated how much the cost of occupational health care services needs per worker, and calculated how much the cost needs per service hour per worker. The results from this show that the cost of occupational health services at workplaces with their own managers used less than the cost of health care agencies, eventually the former gives better services with less cost than the latter. 4. Benefit/Cost ratio is also produced by total benefit/total cost. The result from the above way reads 4.57 as a whole, while their own manager having workplaces reads 4.82 and the agencies do l.56. Even if their own manager performing workplaces spent more cost, this system produces more benefit than the agencies management. 5. The B/C ratio for medical organization such as local clinic, health care center and pharmacy shows more than or equal to at the workplaces controlled by the agencies. It is inferred that benefit would be much less than the cost used, with so being inefficient. 6. It is assumed that the efficiency ratio of health education is equal to reduction rate of workers medical organization visit. Estimated reduction rate 5%, 10%, 15%, show that the efficiency ratio of health education have an effect on producing benefits. It is estimated that more benefit can be produced if more qualitative education will be provided for enhancing health care efficiency. 7. Results of this study cannot be generalized because there are large scale of deviation in case of workplaces with less than 300 full time workers, but B/C ratio reads 2.69 as a whole and 3.25 at workplaces with their own health care manager are higher than 1.63 at the workplaces manged by the agencies. Finally, all the benefit concerning health care services could not be quantified, measured and shown on the value of money. This is a reason that a considerable part of benefits are so underestimated. This is also thought that measurement tools should be developed for measuring benefits of health care services with a comprehensive quantification. in the future. It is also expected that efficiency of occupational health care services should be investigated using cost-effectiveness analysis.

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Some Instances of Manchurian Naturalization and Settlement in Choson Dynasty (향화인의 조선 정착 사례 연구 - 여진 향화인을 중심으로 -)

  • Won, Chang-Ae
    • (The)Study of the Eastern Classic
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    • no.37
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    • pp.33-61
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    • 2009
  • In the late Koryo period, until 14th century, there had been at least two groups of Manchurians who were conferred citizenships; one group was living as an original inhabitant in the coastal area of north­eastern part of Korean peninsular, long time ago, and they were over one thousand households. The other was coming down from inland, eastern part of Yoha River, to the area of Tuman River to settle down and they were at least around one hundred and sixty households, including such tribes as Al-tha-ry, Ol-lyang-hap, Ol-jok-hap and others. They were treated courteously, from the early days of Choson dynasty, with governmental policies in an economic, political, and social ways. They were given, for instance, a house, a land, household furniture, and clothes. They were allowed to get marry with a native Korean to settle down. They were educated how to cultivate their lands. It was also possible for them to be given an official position politically or allowed to take a National Civil Official Examination. The fact they could take such an Examination, in particular, means they were treated fairly and equally, because they also had a privilege to improve their social positions through the formal system as much as common people. Two typical families were scrutinized, in this paper, family Chong-hae Lee and family Chon-ju Ju. All of them were successful to settle down with different backgrounds each other. The former were from a headman, Lee Jee-ran, who controlled his tribe, over five hundred households. He was given three titles of a meritorious retainer at the founding of Chosun dynasty, at the retrieval of armies, and an enshrined retainer. His son, Lee Wha-yong, was also given a vassal of merit who kept a close tie successfully with the king's family through a marriage. Upon the foundation of their ancestors, their grandsons, family Lee Hyo-yang and family Lee Hyo-gang, each, had taken solid root as an aristocratic Yang-ban class. The former became a high officer family, generation by generation, while the latter changed into a civil official family through Civil Official Examinations. They lived mainly around Seoul, Kyong-gi Province and some lived in their original places, Ham-kyong Province. Chu-man, the first ancestor, was given a meritorious retainer at the founding of the dynasty and Chu-in was also given a high officer position from the government. They kept living at the original place, Ham-heung, Ham-kyong Province, and then became an outstanding local family there. They began to pass the Civil Official Examinations. After 17th century on the passers were 17 in Civil Official Examinations and 40 were passed in lower civil examinations. The positions in government they attained usually were remonstrance which position was prohibited particularly to North­Western people at that time. The Chosun dynasty was open to Machurians widely through the system of envoy, convoy, and naturalization. It was intended to build up an enclosure policy through a friendly diplomatic relation with them against any possible invasion from outside. This is one reason why they were supported fully that much in a various way.

Monitoring of a Time-series of Land Subsidence in Mexico City Using Space-based Synthetic Aperture Radar Observations (인공위성 영상레이더를 이용한 멕시코시티 시계열 지반침하 관측)

  • Ju, Jeongheon;Hong, Sang-Hoon
    • Korean Journal of Remote Sensing
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    • v.37 no.6_1
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    • pp.1657-1667
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    • 2021
  • Anthropogenic activities and natural processes have been causes of land subsidence which is sudden sinking or gradual settlement of the earth's solid surface. Mexico City, the capital of Mexico, is one of the most severe land subsidence areas which are resulted from excessive groundwater extraction. Because groundwater is the primary water resource occupies almost 70% of total water usage in the city. Traditional terrestrial observations like the Global Navigation Satellite System (GNSS) or leveling survey have been preferred to measure land subsidence accurately. Although the GNSS observations have highly accurate information of the surfaces' displacement with a very high temporal resolution, it has often been limited due to its sparse spatial resolution and highly time-consuming and high cost. However, space-based synthetic aperture radar (SAR) interferometry has been widely used as a powerful tool to monitor surfaces' displacement with high spatial resolution and high accuracy from mm to cm-scale, regardless of day-or-night and weather conditions. In this paper, advanced interferometric approaches have been applied to get a time-series of land subsidence of Mexico City using four-year-long twenty ALOS PALSAR L-band observations acquired from Feb-11, 2007 to Feb-22, 2011. We utilized persistent scatterer interferometry (PSI) and small baseline subset (SBAS) techniques to suppress atmospheric artifacts and topography errors. The results show that the maximum subsidence rates of the PSI and SBAS method were -29.5 cm/year and -27.0 cm/year, respectively. In addition, we discuss the different subsidence rates where the study area is discriminated into three districts according to distinctive geotechnical characteristics. The significant subsidence rate occurred in the lacustrine sediments with higher compressibility than harder bedrock.