• Journal of the Korean institute of surface engineering
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• v.12 no.3
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• pp.207-216
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• 1979

Environmental pollution or contaminations caused by various kinds of pollutants have become one of most serious problems of our time. Environ mental pollution is the unfavoralble alteration of our surroundings, through direct or indirect effects of changes in energy patterns, rediation levels, chemical and physical constitution and abundances of organisms. These changes may affect humans directly or through their supplies of water and of agicultural and other biological products, their physical objects or possessions, or their opportunities for recreation and appreciation of nature. Pollutants that meet the criteria of this definition of environmental pollution are numerous: gases (such as sulfur dioxide and nitrogen oxides) and paniculate matter (such as smoke particles, lead aerosols, and asbestos) in the atmosphere; pesticides and radioactive isotopes in the atmosphee and in waterways; sewage, organic. chemicals, and phosphates in water; solid wastes on land; excessive heating (thermal pollution) of rivers and lakes; and many others. Some of these pollutants are introduced into the environment naturally, others by human actions, and most in both ways. Our major concer is with environmental pollution resulting wholly or largely as a by-product of human activities, because these can be controlled most readily. Environmental pollution cannot be solved by science and technology alone. It should be handled by an interdisciplinary approach with combined methods of science and technology as wen as social science disciplines for the better solution of this critical problem. In this respect, introducing "Environmental Science," a new scientific approach for the solution of environmental problems, which is now widely accepted by most developed countries of the world will be very helpful for systematization of theoretical basis for a new scientific approach to environmental pollution. Environmental science is "the study of all systems of air, land, water, energy, and life that surround Man. It includes all sciences directed to the system-level of understanding of the environment, drawing especially upon such disciplines as meteorology, geophysics, oceanography, and ecology, and utilizing to the fullest knowledge and techniques developed in such fields as physics, chemistry, biology, mathematics and engineering as well as many social science disciplines, such as economics, such as economics, law, political science and public administration." The components of this discipline are not new, for they are drawn from existing areas of science within biology chemistry, physics, and geoscience. What is really new about environmental science, however, is it siewpoint - its orientation to global problems, its conception of the earth as a set of interlocking, interacting systems, and its interest in Man as a part of these systems.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.1
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• pp.120-131
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• 2005

Statement of problem. More than 70% of patients who need the implant supported restoration are parially edentulous. The principles of design for implant supported fixed partial denture in mandibular posterior region are many and varied. Jurisdiction for their use is usually based on clinical evaluation. There are several areas or interest regarding the design of implant supported fixed partial denture in mandibular posterior region. 1) Straight and tripod configuration in implant placement, 2) Two restoration types such as individualized and splinted restorations. Purpose. The purpose of this study was to compare the amount and distribution of stress around the implant fixtures placed in the mandibular posterior region with two different arrangements and to evaluate the effects of splinting using the photoelastic stress analysis. Material & methods. 1) Production of study model: Mandibular partially edentulous model was waxed-up and duplicated with silicone and two models were poured in stone. 2) Fixture installation and photoelastic model construction: Using surveyor(Ney, USh), 3 fixtures(two 4.0 $\times$13 mm, one 5.0$\times$10 mm, Lifecore, USA) were insta)led in straight & tripod configurations. Silicone molds were made and poured in photoelastic resin (PL-2. Measurements group, USA). 3) Prostheses construction: Four 3-unit bridges (Type III gold alloy, Dongmyung co., Korea) were produced with nonhexed and hexed UCLA abutments and fitted with conventional methods. The abutments were tightened with 30 Ncm torque and the static loads were applied at 12 points of the occlusal surface. 4) Photoelastic stress analysis : The polarizer analyzer system with digital camera(S-2 Pro, Fujifilm, Japan) was used to take the photoelastic fringes and analysed using computer analysis program. Results. Solitary hexed UCLA restoration developed different stress patterns between two implant arrangement configurations, but there were no stress transfer to adjacent implants from the loaded implant in both configurations. However splinted restorations showed lesser amount of stresses in the loaded implants and showed stress transfer to adjacent implants in both configurations. Solitary hexed UCLA restoration with tripod configuration developed higher stresses in anterior and middle implants under loading than implants with straight configurations. Splintied 3 unit fixed partial dentures with tripod configuration showed higher stress development in posterior implant under loading but there were no obvious differences between two configurations. Conclusions. The tripod configuration of implant arrangement didn't show any advantages over the straight configuration. Splinting of 3 unit bridges with nonhexed UCLA abutments showed less stress development around the fixtures. Solitary hexed UCLA restoration developed tilting of implant fixture under offset loads.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.153-158
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• 2004

Preformed stainless steel crown is an useful restorative material for the treatment of badly broken down primary teeth. However iatrogenic damage to adjacent teeth might occur during the process of tooth reduction. Such damages might lead to plaque accumulation and increase the risks of caries initiation. Especially the damage can make a problem in the first permanent molar. Purpose of this study was to investigate an iatrogenic damage to the first permanent molar during preparation of second primary molar for preformed stainless steel crown. Twelve children restored with preformed stainless steel crown to second primary molar were selected. Contact areas were separated with separation elastics, and tooth surfaces were cleaned. After taking negative impression using vinylpolysiloxane impression material, the specimens were examined by scanning electron microscope for the detection of iatrogenic damage. The prevalence of iatrogenic damage was 66.7% and variable appearances and So we can suggest that when preparing teeth for preformed stainless steel crown, we should be careful about adjacent teeth not to make an iatrogenic damage.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.66-72
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• 2012

Autogenous tooth transplantation can be defined as the surgical movement of a tooth from one position in the mouth to another in the same individual. The most common reasons for tooth transplantation include replacement of a missing first molar, transplantation of impacted canines to their normal positions in the arch, and transplantation of premolars in areas of missing teeth, especially in the anterior area of the mouth. The key to successful tooth transplantation is proper selection of graft with adequate root development as well as the design of surgical operation. Root development stage with half to three-quarter-developed roots increase the success rate of autotransplantation. We report the cases of successful autotransplantation which resulted in ideal healing of periodontal ligament, gingiva and alveolar bone. All transplanted teeth presented immature root formation at the moment of the procedure. After surgical procedure, we can observe good healing pattern without endodontic problem.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1744-1751
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• 2011

The concept of the advanced concept technology demonstration (ACTD) has previously been introduced in USA in order to make it possible to rapidly transfer advanced technologies developed in commercial sectors to develop weapon systems in the defense area. Since then in Korea several ACTD programs have been developed and being carried out However, there are few program management methods suitable for the characteristics of the ACTD programs, which requires stringent management of the program requirements and risks due to the radically shortened development time. In this paper such a problem has been addressed and as a solution approach the quality function deployment (QFD) method has been adopted, which is being served as a successful model in various areas such as manufacturing. The QFD method is used in our study to improve communication between various stakeholders involved in the ACTD programs and also to reduce risks related to requirements. Specifically we have developed the ACTD standard templates based on the QFD method and discussed how to use the developed templates. Finally, the application of the study result is demonstrated through the ACTD program of flight information demonstration system and also specific ways are suggested to use the standard templates, to manage requirements, and to reduce risks.

• Korean journal of communication and information
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• v.56
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• pp.219-236
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• 2011

Since the end of the $19^{th}$ century, Korean English-language newspapers have been published in Korea to inform readers about Korea and Korean people's point of view concerning world problems. Among them was the Korean Republic (KR), the former name of the Korea Herald, founded on August $15^{th}$, 1953 (Korean Liberation Day from Japanese colonial rule). This newspaper was started especially to report on international affairs, just after the Armistice agreement was signed on July $27^{th}$, 1953, at the initiative of the first president of the Republic of Korea, Syngman Rhee. He vehemently expressed his and the Korean people's opinion about Korean problems in world politics where big powers were dominating and deciding small countries' destinies. This paper is written to show that Korean English-language newspapers were used as tool of public diplomacy not only for the readers of target countries but also for Korean readers, well before the media diplomacy theory became popular several decades later. In the deplorable world situation where Korea was colonized and divided into halves by the wills of the super powers, the Korean media participated actively via dialogue in English to solve the Korean problem. This paper studies the editorials of the KR for one year, the year just after its foundation. Vis-a-vis the United States, the KR defended its political system of free democracy by insisting on the Korean people's hopes, the reunification of the peninsula and acquiring American assistance in economic and military areas. Regarding Japan, Korea had doubt about its expansionist policy by way of rearmament. First, the Korean government tried to defend its territorial waters, including Dokdo Island. As for multi-lateral relationships, Korea was concerned about the spread of communism to its territory in the world where socialism was dominating.

• Journal of The Korean Association For Science Education
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• v.38 no.5
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• pp.649-665
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• 2018

In this study, we extracted the core competencies of makers through the analysis of critical incident technique and behavioral event interview to explore the nature and attributes of maker education, and then we developed a maker competency model based on these core competencies. As a result, six competency groups and 23 sub-competencies were extracted. In other words, we were able to confirm the existence of integrated thinking competency group consisting of four competencies made up of 'analytic thinking', 'intuitive thinking', 'visual thinking', and 'empirical thinking' and that of collaborative competency group with four competencies of 'sharing', 'communication', 'conflict management', and 'scrupulosity'. In addition, we could also confirm the existence of making mind competency group, which is composed of four competencies namely 'interest in various areas', 'challenge consciousness', 'failure management', and 'pleasure of the making process'. We could also confirm that human-centered competence group consisting of two competencies of 'humanity' and 'user-oriented' and the problem-finding competence group consisting of two competencies of 'observation' and 'recognition of discomfort in daily life'. Lastly, the making practice competency group is composed of seven competencies: 'understanding making tool', 'understanding electricity', 'understanding programming', 'planning', 'hand knowledge', 'information search', and 'direct execution'. We discussed educational implications of these findings.

• Journal of the Economic Geographical Society of Korea
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• v.17 no.4
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• pp.817-831
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• 2014

In this paper insights from studies on the middle income trap and value chains analyses are combined to investigate one particular industry in one particular region: the sugarcane industry in Northeastern Thailand. Focusing on this region enables an in-depth focus on geographical differentiation of the middle income trap. The empirical outcomes demonstrate that policymakers involved with sugar should look at the particular challenges in Northeastern Thailand: 1. The role of brokers which is unaddressed in the current regulatory environment; 2. A lack of information of the regulatory environment among growers; 3. Distrust between growers and millers; 4. Alack of implementation of R&D efforts; 5 .A lack of support from associations; 6. The labor shortage problem, and 7. No incentives for growers, brokers and millers to improve quality and embark on upgrading. Since agricultural value chains in Southeast Asia often start in relatively poor rural areas it is imperative that policymakers balance the interests of upstream, midstream and downstream actors. Unfortunately, this is rather difficult as midstream actors (millers) and wholesalers are powerful and therefore, are in the best position to defend their interests. Our insights could function as comparative material for similar studies within other Southeast Asian upstream value chains.

• Korean Journal of Environment and Ecology
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• v.25 no.3
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• pp.421-431
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• 2011

This study examined visitors' perceptions and attitudes about establishing cable car in Mudeungsan Provincial Park (MPP). Data were collected from 401 respondents by a field questionnaire survey in MPP during the September of 2010. 61.7% of respondents opposed to establishing cable car in MPP while 20.6 percent supported it. Respondents showed high level of belief to possible consequences that establishing cable car will result in 'deterioration of ecosystem and natural landscape', 'crowding problem by increased number of visitors', 'disappearance of naturalness or previous nature experiences in MPP'. Respondents, however, presented low belief to 'positive effects on increasing economic income and local economic growth by attracting tourists'. 32.4 percent of the survey respondents evaluated the present MPP as a place of 'Nature Preservation Area (NPA)' and 10.5% as 'Developed Park Area (DPA)'. 48.8% of respondents answered that MPP should be managed as 'NPA' with only 2.5% as DPA. Respondents' socio-demographic characteristics (i.e., gender, age, education level, length of residence in Gwang-ju city), use patterns (number of visits to MPP or to Jungbong and surrounding areas), and normative place condition of MPP showed relationship with the overall support rates about establishing cable car. The results and their implications were discussed.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.2
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• pp.151-164
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• 2001

Java, used as the most representative object-oriented language, isil becoming the popular language for Internet/Intranet based program development. Moreover, it is used for development language in a variety of areas such as component based development language. In the view of reuse and maintenance of developed program, quality evaluation of program is becoming a more important issue. So, metrics measurement for quality evaluation of program that is developed at present including existing Java application is necessary. However, it is necessary that whether existing object-oriented software metrics is suitable on Java program is to be validated So, in this paper, we build an automated metrics measurement system that needs to validate on object-oriented software metrics and wish to support metrics measurement that is to determine it. The purpose of this system is to support a precise quality evaluation tool. In this system, we apply the metrics classified by Briand. Briand classified the metrics by formalizing mathematically them to verify feasibility of existing object-oriented software metrics. Using the proposed system, we can make comparison and analysis of validation on existing object-oriented metrics by calculating quantitative information more rapidly from Java source program. If there is any problem in feasibility of the metrics, we can establish a suitable metrics on Java program by considering reiJ,1forcement of the existing metrics or proposing new metrics.