• Journal of Community Nutrition
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• 제4권2호
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• pp.130-135
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• 2002

The purposes of this study were to quantify and compare the kind and amount of solid waste generated in two school foodservice operations located in urban and rural areas. A waste stream analysis was conducted to quantify and characterize the kind of waste in the production and service parts of each operation. The SPSS 10.0 for window was used for data analysis. Non-parametric test (Mann-Whitney) was adopted to determine if significant differences exist in amounts of waste generated in the urban school and the rural school. An average of 415 meals, including 43 adult meals, were served daily in the urban school, while an average of 177 meals, including 24 adult meals, were served daily in the rural school. Food waste generated in the production part in the urban school composed approximately 87% and 45%, while that in the rural school composed 71% and 28% by weight and volume, respectively. Waste per meal was not significantly different between the urban school and the rural school in the production part except the cardboard waste. The total waste per meal at lunch was 154g or 465m1 in the urban school and 51g or 334m1 in the rural school. Students in the urban school discarded significantly more food waste and milk than students in the rural school did. The research results suggest that school foodservice dietitians should evaluate the acceptability of menu items based on food waste per meal, and assess the feasibility of implementing a plan for recycling packaging waste and composting organic waste.

• 한국건설관리학회논문집
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• 제9권1호
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• pp.87-95
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• 2008

정부는 2004년 상반기부터 실적단가집을 발행하여 실적공사비에 의한 예정가격 작성방안을 적극 활용하고자 하였다. 그러나, 건설업계에서는 현행 실적공사비제도가 내포하고 있는 문제점으로 인해 사업성 악화를 우려하며 실적공사비제도의 개선을 요구하고 있다. 본 논문은 철근콘크리트 공사의 실적단가와 시장단가의 흐름을 관찰하여 실적공사비제도의 문제점을 확인하고 현행 실적단가 선정 모델을 개선한 새로운 모델을 제시하고자 한다. 개선된 실적단가 선정 모델은 합리 적인 공사비 예측을 통해 관련업체를 효율적으로 지원하여 건설업체의 수익성을 확보하고 실적단가의 신뢰성을 제고할 수 있을 것으로 기대된다.

• 디지털융복합연구
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• 제16권5호
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• pp.115-122
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• 2018

본 연구는 무인자동차 시스템이 상용화에 가까워짐에 따라 소비자들이 느끼게 되는 다양한 요인들 중에서 자율주행에 대한 기술수용정도를 파악하기 위해 기술수용모델(TAM)을 활용하여 사후행동에 미치는 영향을 파악하고자 하였다. 기존 기술수용모델이 제시한 지각된 사용 이용성의 매개효과와 더불어 본 연구에서는 지각된 신뢰(perceived trust)를 제안하여 사후행동에 대한 매개효과를 가설로 제시하였다. 분석방법은 구조방정식을 활용한 경로분석을 활용하였으며, 분석에 사용된 표본은 160명의 응답 중 149개의 유효한 자료를 이용하였다. 매개효과에 대한 가설검증으로 총효과, 직접효과, 간접효과를 확인하였으며, 비모수 bootstrapping 분석을 추가적으로 실시해 가설검증을 실시하였다. 모든 가설은 유의미하였으며 부분적인 간접효과가 있는 것으로 확인되어 매개효과가 있다는 것을 발견하였다.

• The Journal of Advanced Prosthodontics
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• 제9권3호
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• pp.188-194
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• 2017

PURPOSE. This study was to evaluate the effect of repeated ultrasonic scaling and surface polishing with intraoral polishing kits on the surface roughness of three different restorative materials. MATERIALS AND METHODS. A total of 15 identical discs were fabricated with three different materials. The ultrasonic scaling was conducted for 20 seconds on the test surfaces. Subsequently, a multi-step polishing with recommended intraoral polishing kit was performed for 30 seconds. The 3D profiler and scanning electron microscopy were used to investigate surface integrity before scaling (pristine), after scaling, and after surface polishing for each material. Non-parametric Friedman and Wilcoxon signed rank sum tests were employed to statistically evaluate surface roughness changes of the pristine, scaled, and polished specimens. The level of significance was set at 0.05. RESULTS. Surface roughness values before scaling (pristine), after scaling, and polishing of the metal alloys were $3.02{\pm}0.34{\mu}m$, $2.44{\pm}0.72{\mu}m$, and $3.49{\pm}0.72{\mu}m$, respectively. Surface roughness of lithium disilicate increased from $2.35{\pm}1.05{\mu}m$ (pristine) to $28.54{\pm}9.64{\mu}m$ (scaling), and further increased after polishing ($56.66{\pm}9.12{\mu}m$, P<.05). The zirconia showed the most increase in roughness after scaling (from $1.65{\pm}0.42{\mu}m$ to $101.37{\pm}18.75{\mu}m$), while its surface roughness decreased after polishing ($29.57{\pm}18.86{\mu}m$, P<.05). CONCLUSION. Ultrasonic scaling significantly changed the surface integrities of lithium disilicate and zirconia. Surface polishing with multi-step intraoral kit after repeated scaling was only effective for the zirconia, while it was not for lithium disilicate.

• 한국의류산업학회지
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• 제19권2호
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• pp.230-239
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• 2017

In the clothes industry, there are lack of experts including technical designers who can analyze the fit of clothes. This study is to provide practical data available for fit analysis education by distinguishing the differences in standards and aspects of garment fit between experts and novices, through the eye-tracking technology to quantify the sense of fit. For this study, two groups were organized; one composed of 7 experts with over 15 year-experience including technical designers and patternmakers, and the other composed of 7 novices who are students majoring in clothing. Wearing the goggle type eye-tracker Tobii Pro Glasses 2, the participants in the experiments were required to conduct fit analyses for a pair of pants on a live model. After those experiments, they were required to check the items for fit analysis and assess the importance level of them on a questionnaire. The differences between the two groups in the ratios of total visit count and total visit duration by each AIO(Area of Interest) of clothes were analyzed through non-parametric statistical test. The results of eye tracking experiments showed that experts focused on center front and back line, crotch area, and side seam, while novice's fixation points were dispersed around the pants. The survey results showed that the experts put importance on the center line position and its verticality, front-back proportion of side seam line, and front-back proportion of waist line, 71.4~100% of whom checked them, while 14.3% of the novices checked them.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권7호
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• pp.112-120
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• 2015

Statistical trend analysis using the data from the National Groundwater Quality Monitoring Network (NGQMN) of Korea was conducted to establish a new groundwater quality management framework. Sen’s test, a non-parametric statistical method for trend analysis, was used to determine the linear trend of the groundwater quality data. The analysis was conducted at different confidence levels (i.e., at 70, 80, 90, 95, and 99% confidence levels) for three of groundwater quality parameters, i.e., nitrate-nitrogen, chloride, and pH, which have sufficient time series of the NGQMN data between 2007 and 2013. The results showed that different trends can be determined for different depths even for the same monitoring site and the numbers of wells having significant trends vary with different confidence levels. The wells with increasing or decreasing trends were far less than the wells with no trend. Chloride had more wells with increasing trend than other parameters. On the other hand, nitrate-nitrogen had the most wells with increasing trend and concentration exceeding 75% of the threshold values (TVs). Based on the methodology used for this study, we suggest including groundwater TVs and trend analysis to evaluate groundwater quality and to establish an advanced groundwater quality management framework.

• International Journal of Concrete Structures and Materials
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• 제10권sup3호
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• pp.19-31
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• 2016

The objective of this paper is to investigate the effect of thickness and moisture on temperature distributions of reinforced concrete walls under fire conditions. Toward this goal, the first three wall specimens having different thicknesses are heated for 2 h according to ISO standard heating curve and the temperature distribution through the wall thickness is measured. Since the thermal behavior of the tested walls is influenced by thickness, as well as moisture content, three additional walls are prepared and preheated to reduce moisture content and then tested under fire exposure. The experimental results clearly show the temperatures measured close to the fire exposed surface of the thickest wall with 250 mm thickness is the highest in the temperatures measured at the same location of the thinner wall with 150 mm thickness because of the moisture clog that is formed inside the wall with 250 mm of thickness. This prevents heat being transferred to the opposite side of the heated surface. This is also confirmed by the thermal behavior of the preheated walls, showing that the temperature is well distributed in the preheated walls as compared to that in non-preheated walls. Finite element models including moisture clog zone are generated to simulate fire tests with consideration of moisture clog effect. The temperature distributions of the models predicted from the transient heat analyses are compared with experimental results and show good agreements. In addition, parametric studies are performed with various moisture contents in order to investigate effect of moisture contents on the thermal behaviors of the concrete walls.

• 한국안전학회지
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• 제29권5호
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• pp.129-135
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• 2014

In recent studies, construction industry workers with higher job stress and lower work ability were more likely to experience accidents at their workplace. Likewise, fatal accidents rate was higher among simple labor workers compared to technical workers. Therefore the evaluation of a worker's job stress and work ability seems to be important in preventing the occurrence of fatal accidents. To search for ways to reduce job stress and to improve work ability, the current study conducted a job stress analysis based on age, years of service, skill level, hobbies, sleep patterns, and monthly income. For this, the Korean occupational stress questionnaire short form and the Work Ability Index (WAI) developed by the Finnish Institute of Occupational Health (FIOH) were used. In this study, SPSS 12.0K statistics program was used for statistical analysis and significance was verified by the Kruskal-Wallis test and non-parametric tests. The results of this study can be summarized as follows : (1) Simple labor workers had higher job stress and less work ability than technical workers. (2) The more experienced workers had lower job stress and higher work ability. (3) In the case of workers who slept a lot, work ability was higher and job stress was less. (4) Monthly income influenced on the job stress and work ability. (5) Job stress and work ability in accordance with the age difference was not significant.

• Journal of Korean Neurosurgical Society
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• 제42권3호
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• pp.195-199
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• 2007

Objective : Bilateral laminotomy and unilateral laminotomy for bilateral decompression are becoming the minimally invasive procedures for lumbar spinal stenosis (LSS). With the aim of less invasiveness and better preservation of spinal stability. these techniques have been developed. But there are no large randomized studies to show the surgical results between these two techniques. The objective of this study was to examine the safety and efficacy of these two minimally invasive techniques. Methods : A total of 80 patients were included in this study (Group I : bilateral laminotomy, Group II : Unilateral laminotomy for bilateral decompression). Perioperative parameters and complications were analyzed. Symptoms and scores such as visual analog scale (VAS) scores, Oswestry Disability Index (ODI) scores, and SF-36 scores of prospectively accrued patients were assessed preoperatively and at 1 month and 12 months after surgery. Paired-t test, two-sample student-t tests, and non parametric tests were used to determine cross-sectional differences between two groups. Results : No major complications such as spinal instability or deaths occurred during follow-up periods. VAS, ODI scores and SF-36 body pain and physical function scores showed statistically significant improvements in both groups (p<0.001). The significant widening of the spinal canal diameter was also noted in both groups. But, in Group II. there were minor postoperative complications such as dural tear (2 cases 5.0%), fracture of ipsilateral inferior facet (1 case 2.5%), and 5 cases of transient leg symptoms of contralateral side. Conclusion : Both bilateral laminotomy and unilateral laminotomy for bilateral decompression allow achievement of adequate and long-lasting operative results in patients with LSS. But postoperative complications are more frequent in Group II (unilateral laminotomy and bilateral decompression). These results indicate that bilateral laminotomy is the preferred minimally invasive technique to treat symptomatic LSS.

• 한국강구조학회 논문집
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• 제26권5호
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• pp.453-461
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• 2014

본 연구에서는 건축구조용 고성능강 HSA800의 건축구조부재로의 적용을 위한 연구로써, 용접 제작된 각형강관 및 H형강에 대해 단주편심압축 실험을 바탕으로 해석모델을 이용한 검증이 이루어졌다. 특히, 고성능강 조립단주의 유한요소해석을 이용한 변수연구와 P-M 상관관계로부터 현행 기준의 적용여부를 평가하고자 하였으며, 폭두께비와 축력비를 주요변수로 두었다. 변수모델의 P-M상관도 분석결과, 압축력에 대한 비세장단면은 모두 현행기준의 요구에서 크게 상회하는 결과를 얻었고 축력비가 낮을수록 휨강도비에 충분한 여유를 갖는 것을 확인하였다. 압축력에 대한 세장판 단면을 갖는 각형강관의 경우, 현행기준의 요구에 못 미치는 결과를 보였다.