• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.5
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• pp.55-64
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• 2015

In this study, negative air ions, which can increase comfort and positively influence human health, was set as an evaluative factor for school forests. The characteristics, location and microclimate of school forests were examined to determine an effective school forest model for maximum negative air ion generation. It also aimed to provide basic data for the development of urban green fields. The negative air ion concentrations were different according to the green types. The order from the highest to the lowest was: single-layer structure($934ea/cm^3$) > multi-layer structure($794ea/cm^3$) > grass($553ea/cm^3$) > bare ground($529ea/cm^3$). As for the correlation with microclimate, negative air ion concentration was negatively correlated with temperature. The negative air ion concentration was significantly different according to planting type. The negative air ion concentration was higher at single-layer structure sites than at multi-layer structure sites, which appears to indicate that the temperature is higher when the vegetation structure was single-layer compared to multi-layer. Wind speed was higher at the single-layer planted site than at the multi-layer planted site. The vegetation wind shielding effect was lower at single-layer planted sites than at multi-layer planted sites. The single-layer planted site provided more favorable conditions for the generation and dispersion of negative air ions.

• The korean journal of orthodontics
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• v.40 no.2
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• pp.95-105
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• 2010

Objective: To identify clinical, salivary, and bacterial changes during orthodontic treatment with follow-up to 24 months. Methods: In 30 patients, clinical (decayed, missing, and filled surfaces [DMFS], O'Leary's plaque index, and plaque pH), salivary (unstimulated and stimulated saliva, buffer capacity, pH, and occult blood), and bacterial (Streptococcus mutans and Lactobacillus) markers were evaluated. A questionnaire was employed to evaluate their hygienic-dietary habits. Data were analyzed by ANOVA, logistic regression and Spearman's correlation. Results: DMFS increased significantly, whereas the plaque index diminished, plaque pH was more acidic (p = 0.23), and unstimulated salivary flow showed significant differences during the treatment (p = 0.013). Stimulated saliva flow increased in females after the placement of appliances; buffer capacity was diminished in males during the therapy; salivary pH remained at basal values. Bacterial levels and occult blood increased to high-risk levels and were not statistically significant different between genders (p > 0.05). Two major relationships were confirmed: initial plaque with use of dental aids (r = 0.429; p = 0.018) and final DMFS with unstimulated salivary flow (r = -0.372; p = 0.043). Conclusions: The increase in retentive surfaces increased the bacterial levels, plaque pH became acidified, and gingival damage was greater. Buffer capacity was altered but maintained a healthy salivary pH during the treatment.

• Journal of Korea Spatial Information System Society
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• v.1 no.2 s.2
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• pp.63-80
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• 1999

This study presents NGDM(National Geospatial Information Distribution Model) in order to effectively utilize and differently apply geospatial information which is important in the dispersion of GIS. In order to establish the NGDM, this study draws the guideline of NGDM in Korea by analyzing its present condition of domestic and foreign geospatial information distribution. It also investigates some major factors forming the infrastructure of NGDM in regulative, technical, physical, and social aspects. Based on these factors, this study presents a three-staged NGDM that is applicable in Korea. The NGDM consists of four components that are the consumer, supplier, gateway for the clearinghouse and the clearinghouse of the geospatial information. According to the management form of geospatial information, the types of NGDM are classified as the concentration type, the distribution type, and compound type. Also, this study explains the mutual relationship between the NGDM's components and suggests a three-staged NGDM of planting, growth, and maturity period considering comparison results of classified models and development direction of regulation, protocol, communication network, electronic commerce, and etc.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.2
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• pp.96-104
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• 2000

By using the offshore type submersible platform, Artificial sea floor anchored at a depth of forty meters several experimental studies have been conducted successfully during 1996. The facility consists of an artificial sea floor that floats at 7 meters below the surface, a machinery hut that projects above the surface at the center of the structure and a balance weight beneath the structure. The facility can be surfaced easily by using a water discharging pump in the water tank which is located at the center of it. To find out the behavioral character and the gathering factor of fishes around the artificial sea floor, investigations were carried out during the daytime and nighttime by direct observation and by echo-sounder. Around the testing reefs and artificial sea floor, six kinds of fishes were found by diving observation and the dominants were Scomber japonicus, Sebastes thompsoni and Oplegnathus fascitus. As Scomber japonicus was distributed around the artificial sea floor in dense small school, they were not seen elsewhere in the survey area. The artificial sea floor was concluded to act as a schooling ground far Scomber japonicus, Sebastes thompsoni and Oplegnathus fascitus. were close to the testing reefs(within 10m) in the daytime, and were thought to settle on the testing reefs at nighttime, To examine the distribution of 7shes around the artificial sea floor, an acoustic survey over a 1$\times$1km area, 0-50m in depth during the all day. Around the artificial sea floor many thin scattering fish echo(TS-54.5~ -51.5dB) and dense fish echo(TS-41~-38dB) were mainly distributed. Many scattering fish echoes, which were thought to be a mixture of small squid, pelegic crustacea and ethers, were distributed over the whole survey area. A dense fish school stayed beneath the artificial sea floor for a short duration. These phenomena were concluded to show an attraction and detention function of the artificial sea floor.

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.773-782
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• 2002

In this study, a series of fatigue tests are performed in order to estimate quantitatively the characteristics of fatigue crack growth rate according to the base metal, heat affected zone(HAZ) and weld metal, and the welding method and grade of strength of object steels, and the influence on fatigue crack growth rate according to the direction of welded line for high strength steels of SM570, POSTEN60, and POSTEN80 steels. From the fatigue test results, the retardations of fatigue crack growth rate are remarkable in case that the direction of notch is parallel to welded line than in case that the direction of notch is perpendicular to welded line because of compresive residual stress in weld metal & HAZ. And the characteristics of fatigue crack growth rate according to welding method are that the dispersion of fatigue crack growth rate in case of FCAW method is smaller than that of SAW method. Also, it knows that the fatigue crack growth rate converges in high stress intensity factor range. Meanwhile, fatigue safety is guaranteed sufficiently in the object steels because the fatigue crack growth rate in the range of fatigue crack propagation has a similar tendency to the test results & existing results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.56-65
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• 2019

This study examined effects of 12 weeks of body weight based combined exercise training (resistance training for 30 min, aerobic training for 30min) on body composition (% body fat, lean body mass, fat mass and BMI (body mass index)) and cardiovascular factors (ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV)) in elderly women. A total of 32 subjects participated in this study, and were randomly divided into either exercise group (n = 16, EG) or control group (n = 16, CG). All variables at pre-test were analyzed by independent t-test for baseline test, and all data post the study period were analyzed by two-way repeated measures ANOVA with contrast testing (α = 0.05). Our results indicate that body composition (% body fat, lean body mass, fat mass and BMI) in both EG and CG do not differ significantly. However, the right and left sides of baPWV in EG was significantly reduced, as compared to CG. Taken together, these results indicate that combined exercise training for 12 weeks positively influences the cardiovascular factors, and may prevent cardiovascular diseases in elderly females (over 65 years), thereby resulting in increased quality of life for the elderly.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.2
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• pp.51-59
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• 1996

In case waste disposal site is to be constructed close to the underground facilities such as LPG storage cavern which is completely maintained by groundwater pressure, it is generally requested that the possibility on leachate contamination of cavern area be reviewed and the countermeasure, if it is estimated cavern area is severely affected by leachate, be taken into consideration. Prediction was performed and leachate control plan was made using by analytical and the numerical analysis on the leachate migration which is likely to happen at the area between the proposed waste disposal site and the underground LPG storage cavern located at the U petrochemical complex. Analytical solutions were obtained by the conservative mass advection-diffusion equation and the effect of advection and dispersion factor on the leachate migration was reviewed through peclet number calculation and the functional relationship between the factors and leachate transport velocity was established, which leads to enable us to predict the leachate transport velocity without difficulties when different parameters (factors) are used for analytical solution. Numerical solutions were obtained by FEM using AQUA2D which is for the simulation of groundwater flow and contaminant transport. 3-D discrete fracture models were simulated and fracture flow analysis was performed and feasibility study on the water-curtain system was conducted through the fracture connectivity analysis in rock mass. As results of those analyses, it was interpreted that the leachate would trespass on the LPG storage cavern area in 30 years from the proposed wate disposal site and the vertical water-curtain system was effective mathod for the prevention of leachate's migration further into the cavern area.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.470-487
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• 2020

The study was aimed to find out whether there are differences in perception toward multicultural youth's career problems according to the four stages of life cycle(adolescence, pre-marriage, family formation child rearing), and multicultural families and non-multicultural respondents. Also is was aimed to find out if there is an interactive effect on problem recognition. A nationwide survey was conducted using questionnaire on the perception of multicultural youth careers and a total of 1,338 responses were used for the final analysis. For the research purpose, a two-way MANOVA was performed. First it was found that multicultural family members had higher negative perceptions of multicultural appearances than non-multicultural family members had and the adolescents had relatively low negative perceptions of personal relationships and social life adaptation of multicultural youth. Also, as a result of examining whether there is an interaction effect on perception of career problems of multicultural adolescents between multicultural families and their life cycle stages, interaction effects existed in all aspects of family environment, career activities, education, and institutions. It has been shown that there are differences in the perception of career issues among members of multicultural families or among non-cultural families.

• The Journal of the Korean life insurance medical association
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• v.22
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• pp.99-120
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• 2003

그 동안 지속적인 경제성장을 바탕으로 한국의 생명보험산업은 양적으로 성장하였다. 그러나 내면을 살펴보면 외형을 떠받칠 만큼 내실있게 성장했는지에 대해서는 많으 의구심을 갖게 한다. 현실적으로 경제성장을 바탕으로 한 외형성장은 한계를 맞을 수 밖에 없으며, 이제는 질적인 내실을 기하기 위해 그 동안 소홀히 했던 보함산업의 전반의 체질개선이 필요하다. IMF이후 경영이 부실한 보험사들이 퇴출되면서 전면적인 개편이 이루어졌고, 또한 보험사 내부에서도 전반적인 개혁의 필요성을 인식하여 여러 방면으로 방안을 구체화하고 있다. 본 논문은 이러한 상황하에서 생명보험산업의 기존 문제점 개선방안의 일환으로, 보험산업의 가장 핵심분야라 할 수 있는 언더라이팅 분야의 국내현황을 살펴보면서 보험선진국의 제도 및 운영현황과 비교 분석하여 부문별 문제점을 도출하고, 그에 따른 개선방안을 제안하게 되었으며, 본 논문에서 제시된 개선방안을 요약해 보면 다음과 같다. 첫째, 언더라이팅을 신속 정확하게 수행하고 도덕적 위험을 배제하기 위하여 개선된 정보교환시스템 제도를 구축해야 하며, 사정자료의 수집업무를 전문기관에게 아웃소싱함으로써 비용절감을 기하여야 한다. 이와 아울러 모집인의 전문성을 제고시켜 보험계약 청약서와 모집인 보고서가 정확하게 작성되도록 하고 언더라이팅 실적과 연계한 인센티브제도에 의하여 모집수당이 지급되도록 하여 언더라이팅이 효과적으로 수행되도록해야 할 것이다. 둘째, 언더라이팅기법의 선진화를 기함으로써 위험에 상응하는 보험료를 부가하여 위험에 노출되어 있는 가망고객의 보험가입율을 높이고, 보험사고 발생시 실질적인 보험혜택을 누리도록 하여야 한다. 이를 위한 실천방안으로 의적 직업적 재정적 언더라이팅 선진기법을 도입하여 각 부문의 역량을 강화해야 할 것이다. 특히 제도적으로 개인신용정보의 언더라이팅 활용이 제한되어 있는 현실에서 이를 법제도 내로 흡수하면서 개인의 사생활 유지라는 목적을 동시에 달성되도록 하는 재정적 언더라이팅 기법의 강화가 특히 중요하리라 생각된다. 아울러 언더라이팅 업무를 효과적 효율적 수행을 통해 일관성 있는 의사결정이 이루어질 수 있도록 지원하는 언더라이팅 시스템구축을 통해 정형화된 인수과정은 결정시스템화하고, 복잡한 위험의 경우 자문 시스템으로 운영하여 간단한 언더라이팅 업무는 구축된 시스템을 통해 즉각 해결함으로써 시간을 절약할 수 있고, 언더라이팅 인력은 보다 전문적인 부문에 집중하도록 해야 할 것이다. 마지막으로, 비표준위험시장의 활성화를 위해서는 현재의 제약조건인 생명보험 상품개발을 세트형에서 조립형으로 전환하고, 재보험으로 위험을 분산하여 비표준위험의 인수를 증대하여야 할 것이다. 이와 더불어 언더라이팅 과정에서 얻어진 피보험자의 사정자료를 활용하여 고객에게 필요한 의료정보 등을 제공함으로써, 피보험자와 유대관계를 돈독히 하여 기존계약이 계속 유지되도록 하며, 추가계약이 이루어지도록 해야 할 것이다. 이상과 같은 비표준위험의 언더라이팅 개선방안이 보다 효과적으로 수행되고 발전하기 위해서는 통계축적 및 관리, 전문 언더라이터 양성, 전산을 이용한 언더라이팅 확대 등이 이루어져야 하므로 향후 이에 대한 집중적인 연구가 있어야 할 것이다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.4
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• pp.44-55
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• 2013

Intelligent transportation systems allow us to have valuable opportunities for collecting reliable wide-area coverage traffic and weather data. Significant efforts have been made in many countries to apply these data. This study identifies the critical points for classifying rain intensity by analyzing the relationship between rainfall and the amount of speed reduction. Then, traffic prediction performance by rain intensity level is evaluated using relative errors. The results show that critical points are 0.4mm/5min and 0.8mm/5min for classifying rain intensity (slight, moderate, and heavy rain). The best prediction performance is observable when previous five-block speed data is used as inputs under normal weather conditions. On the other hand, previous two or three-block speed data is used as inputs under rainy weather conditions. The outcomes of this study support the development of more reliable traffic information for providing advanced traffic information service.