• Title/Summary/Keyword: Study design

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Shear Strength and Erosion Resistance Characteristics of Stabilized Green Soils (토양안정재를 혼합한 녹생토의 전단강도 및 침식저항특성)

  • Oh, Sewook;Jeon, Jinchul;Kim, Donggeun;Lee, Heonho;Kwon, Youngcheul
    • Journal of the Korean GEO-environmental Society
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    • v.16 no.12
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    • pp.45-52
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    • 2015
  • With the rising interest in the environment, more attention on ecological restoration for damaged slope surface to restore its original state has been drawn. Generally, the most useful method is vegetation based spray work. This method uses green soil including sewage sludge, sawdust, paper sludge, and weathered granite soil. However, because there are neither accurate information nor test values about green soil, green soil is often lost by environmental factors such as rainfalls and strong winds. To solve the problem of green soil, it is necessary to prepare design standards about green soil, and conduct studies to deal with green soil loss in consideration of various variables including basic material property, soil quality of slope surface, and weather. This study was conducted in the mixture of green soil and eco-friendly soil stabilizer. With green soil, basic material property test and compaction test were conducted for the analysis on the basic characteristics of green soil. In the mixture with soil stabilizer at a certain ratio, we conducted shear strength test depending on the ratio in order to analyze the maximum shear strength, cohesion and the change in internal friction angles. Furthermore, in the mixture ratio of green soil and soil stabilizer, which is the same as the ratio in the shear strength test, an inclination of slope surface was made in laboratory for the analysis on erosion and germination rate. Finally, this study evaluated the most effective and economic mixing ratio of soil stabilizer to cope with neighboring environmental factors. According to the test, the shear strength of green soil increased up to 51% rely onto the mixing ratio of and a curing period, and its cohesion and internal friction angle also gradually increases. It is judged that the mixture of soil stabilizer was effective in improving shear strength and thereby increased the stability of green soil.

Evaluation of clinical status of removable partial dentures (가철성 국소의치의 임상적 상태에 대한 평가)

  • Yang, Dong-Seok;Cho, Uk;Jeong, Chang-Mo;Jeon, Young-Chan;Yun, Mi-Jung
    • The Journal of Korean Academy of Prosthodontics
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    • v.47 no.3
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    • pp.320-327
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    • 2009
  • Statement of Problem: Although many efforts have been continually made to estimate long term prognosis of removable partial dentures, the complication of removable partial dentures was still found because of inaccurate fabrication procedure and improper maintenance care. Purpose: The purpose of this study was to evaluate the clinical status of removable partial dentures. Material and methods: A total of 112 individuals with 153 removable partial dentures (35 - 87 years, 64 women and 48 men) were examined by intra-oral examination, diagnostic cast and radiographic examination. Results and conclusion: The results of this study were as follows: 1. Length of service of removable partial dentures was $5.3{\pm}4.3$ years (mean), 4.0 years (median). 2. A total of 45 removable partial dentures were considered failures. The loss of 18 abutments of 369 was founded. 3. Type of arch, Kennedy classification and type of opposite dentition were found to have no influence on longevity and success rate of removable partial dentures (P > .05). 4. Most common major connector was the palatal plate in maxilla and the number of lingual bar and linguoplate designed in mandible were similar. 5. The circumferential type retainer was the most commonly used retainer. 6. Sixty-three percent of the class I and II removable partial dentures incorporated indirect retention into the design. 7. Approximately 81% of the removable partial dentures had at least one defect. Excessive wear of posterior teeth (27.9%), lack of integrity (23.2%), lack of stability (22.6%) were frequent defects of removable partial dentures.

Analysis of Adolescent Awareness of Radiation: Marking the First Anniversary of the Fukushima Nuclear Accident (청소년의 방사선 인식도 분석: 일본 후쿠시마 원전사고 1주년 계기)

  • Park, Bang-Ju
    • Journal of Radiation Protection and Research
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    • v.37 no.2
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    • pp.75-83
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    • 2012
  • Marking the first anniversary of the Fukushima nuclear accident, which took place on March 11th, 2011, the level of adolescent awareness and understanding of radiation was surveyed, and the results were then compared with those for adults with the same questionnaires conducted at similar times. A qualitative survey and frequency analysis were made for the design of the study methodology. Those surveyed were limited to 3rd grade middle school students, 15 years of age, who are the future generation. The questionnaire, which is a survey tool, was directly distributed to the students and 2,217 answers were analysed. The questionnaires were composed of 40 questions, and it was found that Cronbach's coefficient was high with 'self awareness of radiation' at 0.494, 'risk of radiation' at 0.843, 'benefit of radiation' at 0.748, 'radiological safety control' at 0.692, 'information sources of radiation' at 0.819, and 'impacts of Fukushima accident'. The results of the survey analysis showed that the students' knowledge of radiation was not very high with 67.4 points (69.5 points for adults) calculated on a maximum scale of 100 points (converted points). The impacts of the Fukushima nuclear accident were found to be less significant to adolescents than adults, and the rate of answer of "so" or " very so" in the following questions demonstrates this well. It was also shown that the impacts of the Fukushima accident to adolescents were comparatively low with 27.0% (38.9% for adults) on the question of "attitude changed against nuclear power due to the Fukushima accident," 65.7%(86.6% for adults) on the question of "the damages from the Fukushima accident was immeasurably huge," and 65.0% (86.3% for adults) on "the Fukushima accident contributed to raising awareness on the safety of nuclear power plants". The adolescents had a high rate of "average" answers on most of the questions compared with adults, and it can be construed that this resulted from adolescent awareness of radiation not being firmly rooted on themselves. This study was the first of its kind for surveying adolescents regarding the level of awareness of radiation after the Fukushima accident, and the results were compared with the survey results of adults, and they are expected to greatly contribute toward establishing a radiation policy by the government in the future.

The Effects of Cooperative Learning to Study the Unit 'Metabolism' in High School: Application of STAD Model (고등학교 생물 '물질대사' 단원에서 협동학습의 효과: STAD 모형의 적용)

  • Chung, Young-Lan;Lee, Hye-Won
    • Journal of The Korean Association For Science Education
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    • v.23 no.1
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    • pp.35-46
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    • 2003
  • Problem solving ability, having been thought as one of the most important goals of science education is also a primary task for the current education. Indeed, the students' problem solving ability has shown almost no actual progress, despite our long accumulated science education. Under this circumstances, cooperative learning, a way to grow students' positive inter-dependence and problem solving ability in the basis of their active participation and discussion, was proposed as an effective teaching method. But, results have not consistently shown the advantage of cooperative learning over traditional learning for promoting academic achievement in science. Studies have consistently shown greater effectiveness on affective aspects. But, relatively few have focused on biology in Korea. The purpose of this study was to examine the effects of cooperative learning on the achievement and attitude of high school biology students. The pretest-posttest control group design was applied. The sample consisted of 50 11th-grade female students in experimental group(cooperative learning Student Team Achievement Division model) and 50 students in control group(traditional learning). Students in both groups recieved identical content instruction on the unit 'II. Methabolism'. These groups were treated for 13 hours during 5 weeks. Achievement data were collected using a 24-item multiple-choice test(content validity= .85). Science attitude was measured by an instrument which adapted by Kim In Hee(1994). The instrument(Cronbach $\alpha$=.89) included 40 items in four subscales: attitude toward science, social meaning of science, attitude toward science class, and scientific attitude. An analysis of covariance (ANCOVA) was used as the data analysis procedure. For the achievement data, no significant difference exists between the cooperative and traditional groups (p> .05). But, cooperative learning was effective in low-ability students(p < .05). For the science learning attitude data, cooperative learning was more effective than the traditional one(p< .05). Students in the cooperative group acheived better than those in traditional one especially in the subscale of attitude toward science class. There was no meaningful difference of the two methods in both high and average ability students, while cooperative learning was more effective than the traditional one in low ability students(p<.05).

Psychometric Evaluation of a Six Dimension Scale of Nursing Performance and Student Nurse Stress Index Using an Objective Structured Clinical Examination - Modules for Asthma and Type 1 Diabetes (객관구조화 임상시험을 활용한 간호수행능력의 Six Dimension Scale과 간호학생 스트레스 평가지수의 도구 평가-천식 및 1형 당뇨 모듈을 중심으로)

  • Park, Kyong-Ok;Ahn, Young-Mee;Kang, Na-Rae;Lee, Mi-Jin;Sohn, Min
    • Child Health Nursing Research
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    • v.19 no.2
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    • pp.85-93
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    • 2013
  • Purpose: The study purposes were to describe the process of developing the Korean versions of the Six Dimension Scale of Nursing Performance (Six-D) and Student Nurse Stress Index (SNSI) and psychometric evaluation of the two measurements. Methods: This was a methodology study using a descriptive cross-sectional design with 51 nursing students in 4th year of university. Internal consistency reliability was assessed using Cronbach alphas. Construct validity was determined by exploring correlations among Six-D, SNSI, objective structured clinical examination (OSCE), self-efficacy and grade point average (GPA). Results: Internal consistency reliability of Six-D and SNSI was acceptable with Cronbach's ${\alpha}$ of .95 and .82. Correlation analysis to determine construct validity revealed that Six-D presented positive correlations with OSCE (r=.109~.272) and self-efficacy (r=.005~.161) and negative correlation with GPA (r=-.246~-.394), although all were not statistically significant. SNSI presented all negative correlations with OSCE (r= -.007~-.238), self-efficacy (r=-.246~-.394), and GPA (r=-.092~-.426) and were mostly statistically significant except OSCE. Conclusion: Six-D needs more evidence to confirm validity to predict observed clinical competency and theoretical relationships with self-efficacy and GPA. However, SNSI presented trends of expected relationships with relevant variables. Therefore, further research is recommended in testing validity of Six-D with other student populations.

A Study on Development and Site selection of an AIRFIELD (경비행장 개발 및 입지선정에 관한 연구)

  • Park, Sang-Yong
    • The Korean Journal of Air & Space Law and Policy
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    • v.30 no.2
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    • pp.3-36
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    • 2015
  • As of end of 2014, the population engaging in aviation activities for leisure has reached approximately 13 million, where approximately 356 cases involve a general aircraft, 200 cases involve light aircraft, and 636 cases involve an ULM. The industry for leisure has become a very promising industry in line with rapidly rising living standards which are expected to further increase in the future. The demand for such services is expected to increase over time. The purpose of this paper is to review the development and site selection of airfields in anticipation of these developments in the industry. While the government also has experience in the review of airfield location and candidate sites, it is not the government that carries out the actual construction. As such, the feasibility of the site needs to be verified in terms of actual construction. This study identified factors for Site Selection of factors through a review of related documents and existing research reports. A questionnaire was also used to collect the views of experts in the field, which was then analyzed. The Research model was confirmed in the layered form for an AHP analysis. The factors for Site Selection were identified as the technical / operational factors and economic / political elements for a two-stage configuration. The third step consisted of technical and operational elements. The final step is was constructed a total of 11 elements (weather, surface conditions, obstacle limitation surface, airspace conditions, operating procedures, noise problems, environmental issues, availability of facilities, construction and investment costs, contribution to the local economy, accessibility, demand / the proximity of demand). The surveys are conducted for more than 10 General and light aircraft pilots, professionals, and instructor. The analysis results showed a higher level in the technical / operating elements (73.2%) in the first step, while the next step sawa higher level of the operational elements (30.9%) than the other. The factors for Site Selection were any particular elements did not appear high, the weather conditions (17.5%), noise problems (19.8%), the proximity of demand (6%), accessibility (5.7%), environmental issues (11.1%), availability of facilities (8%), airspace conditions (7.9%), obstacle limitation surface (12%), construction and investment costs (4.2%) and to operating procedures (4.9%), contribution to the local economy (3.8%).

Patterns of Cash Payments for Care : Cross-National Comparative Study (장기요양 현금급여 정책의 국가간 비교 연구)

  • Seok, Jae-Eun
    • Korean Journal of Social Welfare
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    • v.58 no.2
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    • pp.273-302
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    • 2006
  • The introduction of cash payments for care is a distinct trend that characterizes changes in care policies since the 1990s. Recently, many developed countries have newly introduced or extended cash payments for care that allow care users to be able to plan themselves for their cares instead of receiving direct care services from the state. Cash payments for care can be said to be one of the alternative policies by which user choices are extended, and it becomes possible to establish demand-cantered care delivery systems more economically and effectively, hence addressing the issue of the financial limitations and rigid systems that are common in modern welfare states, which make it difficult to response to various needs. However, the design and administration of cash for care vary across different countries. Such variations of cash for care policies influence on the combination of consumerism (based on liberal market values intrinsic in the care market) and citizenship based on social solidarity. Those variations eventually produce impacts on the balance of responsibilities and the roles of families, the state and market regarding care in other words, balancing of welfare pluralism. This paper has attempted to find general meanings and particularity of cash for care polices in modem welfare states by means of looking at the characteristics of cash for care policies of four different countries (Netherlands, France, Germany and Italy) and their impacts on their care market. If the four countries are ranked by the degree that they emphasize citizenship in light with social rights, the Netherlands, France, Germany and Italy could be placed in due order. From an economic point of view and in terms of cost containment, those countries will be placed in an inverse order, It is apparent that in the course of planting cash for care policies in the existing social systems involving different socio-cultural conditions and labour markets, sometimes more emphasis is placed on the citizenship of care users, family carers and care providers than on cost containment issue, and sometimes vice versa. Behind this lies the process of different social valuation on what care is about; who can better deliver care; who should be responsible for care; how responsibilities should be shared and so on.

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A Study on the Characteristics of the Korean Juvenile Sound According to Sasang Constitution using PSSC with a Sentence (사상체질음성분석기(PSSC)를 통한 한국인 소아 ${\cdot}$ 청소년의 체질별 음성특성연구 - 단문을 중심으로 -)

  • Heo, Jae-Beum;Jung, Woon-Ki;Choi, Min-Ki;Jeon, Jong-Weon;Kim, Dal-Rae;Yoo, Jun-Sang
    • Journal of Sasang Constitutional Medicine
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    • v.19 no.2
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    • pp.40-52
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    • 2007
  • 1. Objectives and Methods The purpose of this study was to objectify the diagnosis of Sasang Constitution. 63 Male Juvenile's and 151 Female Juvenile's sentences were analyzed into 73 factors like Pitch, APQ, Shimmer, Octave and Energy, etc. Juvenile's sentences were classified into 6 categories: total Male Juvenile group, under 12 years old Male Juvenile grout, over 13 years old Male Juvenile group, total Female Juvenile group, under 12 years old Female Juvenile group and over 13 years old Female Juvenile group. 2. Results 1) In Total Male Juvenile group, there were no significant differences among constitutional groups in APQ and Octave segment. Taeumin's Center freq.(3) was significantly high compared with Soyangin group. Soeumin's Center freq.(5) was significantly high compared with Soyangin and Taeumin groups. Taeumin's Octave3 Shimmer was significantly high compared with Soeumin group. Soeumin's Octave6 Shimmer was significantly high compared with Taeumin group. Solyangin's D# Tot E was significantly high compared with Taeumin group. 2) In Under 12 years old Male Juvenile group, there were on significantly among constitutional groups in Pitch, APQ, Octave and Energy segment. Taeumin's Octave3 Shimmer and G Shimmer(1) were significantly high compared with Soeumin group. 3) In Over 13 years old Male Juvenile group, there were no signigicant differences among constitutional groups in Pitch, APQ and Shimmer segment. Soyangin's and Soeumin's Octave6 were significantly high compared with Taeumin group. Soyangin's $0k{\sim}2k$ Total Sum, $0k{\sim}2k$ Dev., $2k{\sim}4k$ Total Sum, $2k{\sim}4k$ Dev., A Dev.(1), D# Dev.(1) and G# Dev.(1) were significantly high compared with Taeumin group. Soyangin's and Soeumin's G# Tot E were significantly high compared with Taeumin group. 4) In Total Female Juvenile group, there were no significant differences among constitutional groups in Pitch and APQ segment. Soeumin's Octave4 Shimmer was significantly high compared with Soyangin group. Soyangin's Octave6 was significantly high compared with Soeumin group. Solyangin's 2k-4k Total Sum and B Tot E were significantly high compared with Soeumin group. 5) In Under 12 years old Female Juvenile group, there were no significant differences among constitutional groups in APQ and Energy segment. Soeumin's and Taeumin's Center Pitch and Pitch were significantly high compared with Soyangin group. Soyangin's Center freq.(1) and Center freq.(7) were significantly high compared with Soeumin and Taeeunin groups. Soyangin's and Taeumin's B Shimmer(1) and F# Shimmer(1) were significantly high compared with Soeumin group. Soeumin's D Shimmer(1) was significantly high compared with Soyangin group. Taeumin's and Soeumin's G# Shimmer(1) were significantly high compared with Soyangin group. Soyangin's and Taeumin's Octave2 were significantly high compared with Soeumin group. 6) In Over 13 years old Female Juvenile group, there were no significant differences among constitutional groups in Pitch, APQ and Octave segment. Soeumin's Octave4 Shimmer was significantly high compared with Soyangin group. Soyangin's B Dev.(1) and F Dev.(1) were significantly high compared with Soeumin group. 3. Conclusions In juvenile groups, some sound factors are regarded as useful. PSSC are thought to be the objertive way to diagnose the Consitution and more participants are needed to get more efficiencies using PSSC.

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Response of Ground Beetles (Coleoptera: Carabidae) to Vegetation Structure in Wildlife Crossings (생태통로 내부 식생구조에 대한 지표성 딱정벌레류(딱정벌레목: 딱정벌레과)의 반응)

  • Jung, Jong-Kook;Park, Yujeong;Lee, Sun Kyung;Lee, Hyoseok;Park, Young-gyun;Lee, Joon-Ho;Choi, Tae Young;Woo, Donggul
    • Korean Journal of Environment and Ecology
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    • v.30 no.2
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    • pp.185-198
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    • 2016
  • Korea has put in significant efforts to increase the number of wildlife crossings between fragmented habitats to prevent loss of biodiversity and to encourage the habitat connectivity in Korea. However, there is a lack of biological data on the effect of vegetation structure in these wildlife crossings and guidelines for design and management of wildlife crossing structures in Korea. Therefore, we selected ground beetle assemblages as model organisms to compare the effect of vegetation structure in wildlife crossings, i.e. bare ground- and shrub-type corridors, in agro-forested landscapes. For this study, 4,207 ground beetles belonging to 33 species were collected through pitfall trapping along the northern forest-corridor-southern forest transects from late April to early September in 2015. Dominant species, abundance, and species richness of ground beetles were significantly higher in the shrub-type corridors than the bare ground-type corridors. Also, the species composition of bare ground-type corridor was significantly different compared to the other habitats such as shrub-type corridor and forests. Similarly, environmental variables were also influenced by vegetation management regimes or trap locations. Collectively, our study clearly indicates that the movement of forest associated ground beetles between forest patches can increase as the vegetation in wildlife crossings becomes complex. Although further studies are needed to verify this, there are indications that the current wildlife crossings that comply with the guidelines may be unfriendly to the movement of ground dwelling arthropods as well as ground beetles. To enhance the ecological function of wildlife crossings, the guidelines need to be rectified as follows: 1) Shrubs or trees should be planted along the corridor verges to provide refuge or movement paths for small mammals and ground dwelling arthropods, and 2) Open spaces should be provided in the middle of the corridors to be used as a path for the movement of large mammals.

Optimum Synthesis Conditions of Coating Slurry for Metallic Structured De-NOx Catalyst by Coating Process on Ship Exhaust Gas (선박 배연탈질용 금속 구조체 기반 촉매 제조를 위한 코팅슬러리 최적화)

  • Jeong, Haeyoung;Kim, Taeyong;Im, Eunmi;Lim, Dong-Ha
    • Clean Technology
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    • v.24 no.2
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    • pp.127-134
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    • 2018
  • To reduce the environmental pollution by $NO_x$ from ship engine, International maritime organization (IMO) announced Tier III regulation, which is the emmision regulation of ship's exhaust gas in Emission control area (ECA). Selective catalytic reduction (SCR) process is the most commercial $De-NO_x$ system in order to meet the requirement of Tier III regulation. In generally, commercial ceramic honeycomb SCR catalyst has been installed in SCR reactor inside marine vessel engine. However, the ceramic honeycomb SCR catalyst has some serious issues such as low strength and easy destroution at high velocity of exhaust gas from the marine engine. For these reasons, we design to metallic structured catalyst in order to compensate the defects of the ceramic honeycomb catalyst for applying marine SCR system. Especially, metallic structured catalyst has many advantages such as robustness, compactness, lightness, and high thermal conductivity etc. In this study, in order to support catalyst on metal substrate, coating slurry is prepared by changing binder. we successfully fabricate the metallic structured catalyst with strong adhesion by coating, drying, and calcination process. And we carry out the SCR performance and durability such as sonication and dropping test for the prepared samples. The MFC01 shows above 95% of $NO_x$ conversion and much more robust and more stable compared to the commercial honeycomb catalyst. Based on the evaluation of characterization and performance test, we confirm that the proposed metallic structured catalyst in this study has high efficient and durability. Therefore, we suggest that the metallic structured catalyst may be a good alternative as a new type of SCR catalyst for marine SCR system.