• 한국가구학회지
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• 제19권6호
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• pp.411-419
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• 2008

Xylia xylocarpa is fast-growing trees that are currently planted on trial basis in Sabah, Malaysia. The wood quality of trees grown in Sabah may differ from those grown in other places due to the environmental factors. Five 9-year-old trees of each species were extracted from their respective plots at Luasong, Tawau. Wood specimens were prepared from three height levels; bottom, middle and top, at the inner and outer radial positions. The within-tree and between-tree variations of physical properties of these species were analyzed. The basic density, oven-dry density and green moisture content(MC) are 0.72g/$cm^3$, 0.78g/$cm^3$ and 49.8% respectively. The shrinkage from green to oven-dry conditions for the radial and tangential directions were 3.35% and 5.76%, respectively. The trends of within-tree variations for most properties were more consistent in radial rather than vertical direction. This suggests diameter growth to be a more important factor contributing to the variations compared to height. Samples from the outer part of the stem were found to have higher density, shrinkage and mechanical strengths. The between-trees variations of some wood properties were found to be significantly different, probably due to genetic and micro-environmental factors. Significant correlation was recorded among the physical properties of the species. The true potential of X. xylocarpa for end-uses would be enhanced by further research such as the study on properties of wood from different sites and other properties like durability, seasoning, processing and machining characteristics. The characteristics of X. xylocarpa are comparable to a number of local popular hardwood species, indicating its suitability for heavy construction uses.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.529-534
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• 2005

This study performed an physical analysis on the characteristics of urban environmental sound divided into three parts depending on their features. Object sounds were classified into traffic sound, waster sound and spatial sound. Traffice sound was selected because it is dominant sound in urban environment, and water sound is selected because it generally supplies pleasantness in contrast to traffic sound, Finally spatial sound was considered because it represents sound in various places of city having lots of behaviors and types of sound due to them. Physcal analysis was carried out using sound quality indices based on Zwicker's loudness, $L_{Aeq}$(equivalent noise level), Ln(percentile noise level) and other acoutical attributes applied to previous study. Through the analysis, this study aims to compare the acoustical characteristics of urban environmental sound and to provide fundamental data for the evaluation of urban environmental sound.

• 한국실내디자인학회논문집
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• 제3호
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• pp.10-17
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• 1994

Restaurant is a settign for est and social intercousrse fo rpeople in the cities, and is essential to provide its users with pleasant and comfort space. Color is used as a design tool which has most powerful effect to change the nature of a space and atmosphere, As a basic study for desirable environmental color for restaurant, this is studied mainly on the following discussion points. 1) Inportance of environmental color and its role in accordance with space characteristics as restaurant. 2) The psychological effects of color in the clinetes, color conditioning of the dining ares, problem of change in the appearance of color in the selection of materials and color harmony of total environments. 3) Prior to color planning in detail , the nature and characteristics each restaurant contains and their correlation with various locational , physical , social environmental , human variables have been analyzed. And the total atmosphere of the dining area as a place where the clients finally stay has been dealt with various visual , environmental and functional problems of color about fixed elements such as the wall. the floor, the ceiling and semifixed elements such as tables, chairs, etc.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2009년도 춘계학술발표회 논문집
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• pp.23-28
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• 2009

The purpose of this study was to improve not only wet-end performances but also paper characteristics by the modification of various factors like molecular design and ionic characteristics of polyacrylamides First of all physical characteristics were observed after modify molecular design of the cationic polyacrylamides to linear, branched and cross-linked. In addition it was found analysis method to confirm branch degree of cationic polyacrylamides to combine ionic titration characteristics and spectroscopic behavior, After application of these structure modified polyacrylamides to the multiple retention systems with inorganic microparticles, it was found adjusting of branch degree of polyacrylamides was very important to optimize wet-end improvement. Second, After polymerization of amphoteric polyacrylamide to have both of cationic and anionic functional group in the polymer, we observed not only physical characteristics but also wet-end improvement to apply recycled pulp and found that the improvement of solution stability to prevent hydrolysis and increase of ash retention dramatically to compare traditional cationic polyacrylamide retention aid, Finally, After polymerization of anionic polyacrylamide, we observed not only wet-end improvement but also paper characteristics to apply preflocculation of PCC and it was found the improvements of flocculation efficiency, retention, ash retention, optical properties of the paper and bursting strength to compare traditional preflocculant of cationic polyacrylamide.

• 한국수산과학회지
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• 제37권4호
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• pp.312-322
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• 2004

Physical and geoacoustic properties of inner shelf sediment in the South and Southeastern Seas of Korea have been studied based on six piston core samples. The sediments are largely composed of homogeneous mud except the core from the southeasternmost part of the area. Both physical and geoacoustic properties and mean grain size are relatively uniform with sediment depth, suggesting little effect of sediment compaction and/or consolidation. Mean grain size appears to be the most Important variable to determine the physical and acoustic properties. In contrast, the attenuation shows more or less fluctuations. Correlations between physical properties and sediment texture show slight deviations from those of the compared data, caused by the difference of sedimentary processes, mineral composition, and the difference of measurement system. In particular, the velocity is lower (approximately 20-30 m/s) than that of the previous data measured in the same area. This is probably due to the difference in velocity measurement system (particularly, error by a length of sample). We propose new relationships for physical and geoacoustic characteristics of shelf sediment in the study area.

• Geomechanics and Engineering
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• 제32권2호
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• pp.233-244
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• 2023

With the increasing amount of resources required by the society development, mining operations go deeper, which raises the requirements of studying the effects of temperature on the physical and mechanical properties of coal and adjacent rock. For now, these effects are yet to be fully revealed. In this paper, a mechanical-electromagnetic radiation (EMR) test system was established to understand the mechanical deterioration characteristics of coal by the effect of thermal treatment and its deformation and fracture characteristics under thermo-mechanical coupling conditions. The mechanical properties of high-temperature-treated coal were analyzed and recorded, based on which, reasons of coal mechanical deterioration as well as the damage parameters were obtained. Changes of the EMR time series under unconstrained conditions were further analyzed before characteristics of EMR signals under different damage conditions were obtained. The evolution process of thermal damage and deformation of coal was then analyzed through the frequency spectrum of EMR. In the end, based on the time-frequency variation characteristics of EMR, a method of determining combustion zones within the underground gasification area and combustion zones' stability level was proposed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1491-1495
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• 2004

For the evaluation of the mobile robot performance in complex environments, the experimental approach in an actual physical environment has been commonly taken. In the physical experimental approach, however, it is quite difficult to define the proper environment for the evaluation due to the lack of commonly agreed characteristics of the test environment. Particularly the number of combinations of types and physical parameters of the obstacles that the mobile robot is expected to deal with is practically unlimited. In an effort to simplify and improve the effectiveness of the evaluation process, we propose an evaluation method using decomposed environmental elements, where we evaluated the performance of the robot for a small group of simple and decomposed obstacle components, for examples projection and slope, instead of a large group of complicated random obstacles. The paper describes a set of simple obstacle models and performance parameters that we have chosen for the effective evaluation process. As an alternative to the physical experimental evaluation approach, in this paper, we used a virtual evaluation environment where the robot and the physical test environment has been modeled using a commercial multi-body dynamics analysis packaged called RecurDyn.

• 한국산업보건학회지
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• 제27권3호
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• pp.201-209
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• 2017

Objectives: This study was conducted to assess the association between level of physical activity and depressive symptoms among Korean male workers. Methods: A self-administered questionnaire was distributed and anthropometric measurements were conducted with 1,379 male workers during a general health check. From this data, we identified the general characteristics, levels of physical activity(IPAQ), and depressive symptoms(CES-D) of the study population. We conducted univariate logistic regression to verify the variables that affect depressive symptoms and multivariate logistic regression to calculate odds ratios. Results: Among the 1,379 male workers, 43.4% were in the insufficiently active group(IPAQ category 1) and 22.8% were in the depressive symptom group($CES-D{\geq}16$). The odds ratio(OR) for depressive symptoms was statistically higher in the insufficiently active group, workers aged over 30, the shift work group, and the unmarried group. Adjusted for those variables, the ORs for depressive symptoms were found to be 1.45(95% CI=1.25-2.11), 1.15(OR=1.15, 95% CI=1.08-1.99) and 1.75(95% CI=1.48-2.02), for the insufficiently active group, workers aged over 30, and the shift work group, respectively. Conclusions: We found physical inactivity, age, marital status, and shift work to be associated with depressive symptoms among male workers. This study supports the suggestion that physical activity can be helpful to reduce depressive symptoms among workers.

• 한국치위생학회지
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• 제19권5호
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• pp.791-802
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• 2019

Objectives: The purpose of this study was to investigate the relevance of stress and stress amounts of physical environment factors and interpersonal factors of clinical practice institution of dental hygiene department students. It is in order to create condition to focus on clinical practice institution. Methods: The participants in this study were 231 dental hygiene department students engaged in clinical practice; the survey was conducted from September 1 to 30, 2018, using a structured questionnaire (1040460-A-2018-036). The questionnaire consisted of items on participants' general characteristics (4 items), characteristics of the clinical practice institution (9 items), stress from environmental factors (8 items), stress from interpersonal factors (7 items), and stress amounts of BEPSI (5 items). The collected data were compared and analyzed using a t-test, ANOVA, and multiple regression. Results: The physical environment and interpersonal factors of stress according in clinical practice institutions were statistically significant. In case of a number of dentists (p<0.05), subjective practice atmosphere (p<0.001), practice satisfaction (p<0.001), and kindly teach (p<0.001). The factors affecting the amount of stress on the characteristics of the clinical practice institution were that the dental clinic, the relationship with the dental hygienist is common, the number of dentists is 4 or more, and there is no resting room. Conclusions: The selected clinical practice institutions should provide dental hygiene department students with places to relax and a systematic hands-on manual.

• 산업경영시스템학회지
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• 제22권52호
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• pp.241-246
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• 1999

In this study, to specify an evaluation of human sensibility, the types of color, intensity of illuminations and lights consisting work environmental condition are decided, and image data from examining the change of human sensibility followed by changes of the above three conditions are obtained. Using the factor analysis and quantification theory in multi-variate analysis type of Sensibility Ergonomics, determinating the structure of factors, specifying the relations of environmental conditions and factors can be done so that the structure of image on human sensibility space with the change of environmental conditions is analyzed.