• 제목/요약/키워드: Sample Size

검색결과 3,936건 처리시간 0.033초

Characterization of CdSe Thin Film Using Chemical Bath Deposition Method (Chemical Bath Deposition 방법으로 제작한 CdSe 박막의 특성)

  • Hong, K.J.;Lee, S.Y.;You, S.H.;Suh, S.S.;Moon, J.D.;Shin, Y.J.;Jeong, T.S.;Shin, H.K.;Kim, T.S.;Song, J.H.;Rheu, K.S.
    • Journal of Sensor Science and Technology
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    • 제2권1호
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    • pp.81-86
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    • 1993
  • Polycrystalline CdSe thin films were grown on ceramic substrate using a chemical bath deposition (CBD) method. They were annealed at various temperature and X-ray diffraction patterns were measured by X-ray diffractometer in order to study CdSe polycrystal structure. Using extrapolation method of X-ray diffraction patterns for the CdSe samples annealed in $N_{2}$ gas at $450^{\circ}C$ it was found hexagonal structure whose lattice parameters $a_{o}$ and $c_{o}$ were $4.302{\AA}$ and $7.014{\AA}$, respectively. Its grain size was about $0.3{\mu}m$. Hall effect on this sample was measured by Van der Pauw method and studied on carrier density and mobility depending on temperature. From Hall data, the mobility was likely to be decreased by piezo electric scattering at temperature range of 33 K and 200 K, and by polar optical scattering at temperature range of 200 K and 293 K. We measured also spectral response, sensitivity (${\gamma}$), maximum allowable power dissipation and response time on these samples.

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The Study on Standard Bodytype for Korean Women between the ages of 18 and 24 years old(Part I) -focusing on the analysis of the High-frequency type and the High-frequency range- (18~24세 한국인 여성의 표준체형에 관한 연구(제1보) -다빈도유형 및 다빈도구간에 대한 분석을 중심으로-)

  • 이정임;남윤자
    • Journal of the Korean Society of Clothing and Textiles
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    • 제26권5호
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    • pp.630-641
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    • 2002
  • The purpose of this study is to suggest the standard of bodytype which offers various data with regard to three-dimensional characteristics of body, and which offers the criterion for the sizes and shapes to interpret various bodytypes, to estimate filling, and to construct ready-made clothing. In this study, standard bodytype was defined as a typical type with beautiful proportion and shape which a large number of people have, too. In order to continue this study, there were two ways of analyzing bodytypes of subjects in the view of statistics and beauty. We primarily carried on statistical analysis in this report. Taken as a sample, the subjects were ninety-seven females who were between the ages of 18 and 24 years o1d. They were measured on November 1999. The data of seven hundred and few females, 18∼24 year-old, from the National Somatometry Survey of 1997 were used for analysis, too. Three kinds of classification methods were used for statistical analysis. The first method was based on the lateral view of the body, the second was based on the Factor and Cluster analysis of the photographic measurements of each of the anterior and lateral body, and the third was based on the Factor and Cluster analysis of the anthropometric measurements of the whole body. From the analysis on the distribution of R hrer Index the difference of width, the difference of depth, the proportion of height and head height, the High-frequency Proportion(H.P.)range were selected. The straight type from the lateral view, High-frequency type from each method, and subjects in H.P. range were compared with each other. As the result, it was confirmed that it is proper to base on the size and shape of subjects in H.P. range to analyze the standard bodytype.

Synthesis of Multi-Terminalized Magnetic-Cored Dendrimer for Adsorption of Chromium and Enhancement of Magnetic Recovery (크롬 흡착 및 자성회수율 향상을 위한 멀티터미널 자성코어 덴드리머의 합성)

  • Yeo, In-Hwan;Jang, Jun-Won;Kim, Lyung-Joo;Park, Jae-Woo
    • Journal of Korean Society of Environmental Engineers
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    • 제34권9호
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    • pp.613-622
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    • 2012
  • A chrome absorbent that is useful in rapid magnetic recovery and recycling was developed though a synthesis of Multi-Terminalized Magnetic-core Dendrimer (MTMD). Divergence through coprecipitation and rotation growth was used for synthesis. The dendrimer was multi-terminilized through methyl propionate and glutaric acid. The property analysis of the synthesized sample was performed through XRD, FT-IR, TEM, EDS, TGA and zeta potential analyzer. A magnetic-core of MTMD had a magnetite crystal and the size of 4th generation dendrimer was identified to be from 15 nm to 20 nm. Through the analysis of the TGA, the rate of the dendrimer branch for the first generation dendrimer was about 7% and 3% of diminished weight occurred as the generation grows. Also, the potential of the dendrimer when multi-terminalized, had variation from 25.26 mV to -6.53 mV. As a result of MTMD adsorption experiment, it absorbed more than 80% within 5 minutes and indicated absorptivity of 6.308 mg/g. When it was compared with COOH Dendrimer (COOH-D) after magnetic recovery, the recovery time was rapidly reduced by more than half and it could recover 100% within 30 minutes. In case of the regeneration experiment that used chrome, it was identified to maintain the same adsorptivity for four runs.

An evaluation of the composition and elements in Korean traditional interior space - On Choosa-Gotack in the Chosun dynasty - (한국전통 실내공간의 구성방법과 요소 분석을 통한 의미 고찰 - 조선조 추사고택을 중심으로 -)

  • 천진희
    • Archives of design research
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    • 16호
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    • pp.101-110
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    • 1996
  • CHOOSA GORACK which is a typical example of traditional houses in the CHO SEON dynasty consists of the four terraced builfing group. Among those,SADANG CHAI are located in the highest level,and SADANG CHAI and SADANG CHAI are toward south direction.It means that building orientation and level were influenced by the distinction of social level and the idea of ancester worship. Floor and ceiling level in the same building is different which was caused by the distinetion of social level in the CHO SEON dynasty and an ariental dual as a variety of openings,exposed ceilings,and furniture against a wall were creating a typical Korean visual harmony. Although the furniture and equipments were very important elements in ONDOL BANG the occupance ratio of these were low because the free space in BANG should be utilized effectively to accommodate the space variation.Both an AN CHAI and SARANG CHAI were composed by the standard space module called KAN.And interior elements were established by several factors such as the human scale,the behavior pattern in traditional sitting life style, and the lumber size of post and lintel construction of Korean house.BANG and DAE GHUNG, composed of KAN,were expanded and arranged side by side so that the natural light and ventilation through them could be used in the result of the kind of lay out,traffic circulation was disturved.In conclusion,CHOOSA GOTACK was formed by the sirect effice of the KOREAN penisula. However this study was based on one sample. It may not enough to deduct soild conclusion.Therefore continuous and farher study is needed for the sestemane evaluation.

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A Study on the Measurement of Activity Concentrations of Pu and Am and Their Isotopic Ratios in the Radioactively Contaminated Soil (방사능으로 오염된 토양에 대한 Pu 및 Am 방사능 농도 및 동위원소비 측정에 대한 연구)

  • Lee, Myung Ho;Song, Byoung Chul;Park, Young Jai;Kim, Won Ho
    • Analytical Science and Technology
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    • 제17권6호
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    • pp.514-519
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    • 2004
  • Soil samples collected from around the BOMARC Missile Site were measured for their activity concentrations and isotopic ratios of Pu and Am isotopes with particle sizes. The activity concentrations of Pu and Am in the BOMARC soil were remarkably higher than the fallout levels, and the activities decreased nearly exponentially with an increasing particle size of the soil due to a decreasing surface area. The activity ratios of Pu-238 / Pu-239, 240, Pu-241 / Pu-239, 240 and Am-241 / Pu-239, 240 observed in the BOMARC soil were much lower than those attributed to the nuclear reprocess plants and the Chernobyl fallout. Also, the atomic ratio of Pu-240 / Pu-239 in the BOMARC soil was remarkably lower than the fallout value influenced by the nuclear weapons testing and the Chernobyl accident. The atomic ratio of Pu-240 / Pu-239 was so close to the value of the weapons grade Pu released from the crash of a B52 plane in the Thule of the Greenland, such that the Pu isotopes detected in the BOMARC soil could have originated from the weapons grade plutonium.

A Statistical Study Evaporation tn DAEGU Area (대구지방의 증발량에 대한 통계학적 연구)

  • 김영기
    • Magazine of the Korean Society of Agricultural Engineers
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    • 제15권4호
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    • pp.3160-3169
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    • 1973
  • Rainfall, evaporation, and permeability of water are the most important factors in determining the demand of water. The Daegu area has only a meteorologi observatory and there is not sufficient data for adapting the advanced method for derivation of the estimated of evaporation in the Daegu area. However, by using available data, the writer devoted his great effort in deriving the most reasonable formula applicable to the Daegu area and it is adaptable for various purposes such as industry and estimation of groundwater etc. The data used in this study was the monthly amount of evaporation of the Daegu area for the past 13 years(1960 to 1970). A year can be divided into two groups by relative degrees of evaporation in this area: the first group (less evaporation) is January, February, March, October, November, and December, and the second (more evaporation) is April, May, June, July, August, and September. The amount of evaporation of the two groups were statistically treated by the theory of probability for derivation of estimated formula of evaporation. The formula derved is believed to fully consider. The characteristic hydrological environment of this area as the following shows: log(x+3)=0.8963+0.1125$\xi$..........(4, 5, 6, 7, 8, 9 month) log(x-0.7)=0.2051+0.3023$\xi$..........(1, 2, 3, 10, 11, 12 month) This study obtained the above formula of probability of the monthly evaporation of this area by using the relation: $F_(x)=\frac{1}{{\surd}{\pi}}\int\limits_{-\infty}^{\xi}e^{-\xi2}d{\xi}\;{\xi}=alog_{\alpha}({\frac{x_0+b'}{x_0+b})\;(-b<x<{\infty})$ $$log(x_0+b)=0.80961$ $$\frac{1}{a}=\sqrt{\frac{2N}{N-1}}\;Sx=0.1125$$ $$b=\frac{1}{m}\sum\limits_{i-I}^{m}b_s=3.14$$ $$S_x=\sqrt{\frac{1}{N}\sum\limits_{i-I}^{N}\{log(x_i+b)\}^2-\{log(x_i+b)\}^2}=0.0791$$ (4, 5, 6, 7, 8, 9 month) This formula may be advantageously applied to estimation of evaporation in the Daegu area. Notation for general terms has been denoted by following: $W_(x)$: probability of occurance. $$W_(x)=\int_x^{\infty}f(x)dx$$ P : probability $$P=\frac{N!}{t!(N-t)}{F_i^{N-{\pi}}(1-F_i)^l$$ $$F_{\eta}:\; Thomas\;plot\;F_{\eta}=(1-\frac{n}{N+1})$$ $X_l\;X_i$: maximun, minimum value of total number of sample size(other notation for general terms was used as needed)

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The study on the Crushability of Weathered Cranite Soils (화강암질 풍화토의 파쇄성에 관한 연구)

  • 도덕현;강우묵
    • Magazine of the Korean Society of Agricultural Engineers
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    • 제21권2호
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    • pp.81-103
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    • 1979
  • The weathered granite soil involves problems in its stability in soil structures depending upon the reduction of soil strength due to the water absorption, crushability, and content of colored mineral and feldspar. As an attemt to solve the problems associated with soil stability, the crushability of weathered granite soil was investigated by conducting tests such as compaction test, CBR test, unconfined compression test, direct shear test, triaxial compression test, and permeability test on the five soil samples different in weathering and mineral compositions. The experimental results are summarized as follows: The ratio of increasing dry density in the weathered granite soil was high as the compaction energy was low, while it was low as the compaction energy was increased. The unconfined compressive strength. and CBR value were highest in the dry side rather than in the soil with the optimum moisture content, when the soil was compacted by adjusting water content. However, the unconfined compressive strength of smples, which were compacted and oven dried, were highest in the wet side rather than in soil with the optimum moisture content. As the soil becomes coarse grain, the ratio of specific surface area increased due to increased crushability, and the increasing ratio of the specific surface area decreased as the compaction energy was increased. The highest ratio of grain crushability was attained in the wet side rather than in the soil with the optimum moisture content. Such tendency was transforming to the dry side as the compaction energy was increased. The effect of water on the grain crushability of soil was high in the coarse grained soil. The specific surface area of WK soil sample, when compacted under the condition of air dried and under the optimum moisture content, was constant regardless of the compaction energy. When the weathered granite soil and river sand with the same grain size were compacted with low compaction energy, the weathered granite soil with crushability had higher dry density than river sand. However, when the compaction energy reached to certain point over limitation, the river sand had higher dry density than the weathered granite soil. The coefficient of permeability was lowest in the wet side rather than in the optimum moisture content, when the soil was compacted by adjusting soil water content. The reduction of permeability of soil due to the compaction was more apparent in the weathered granite soil than in the river sand. The highly significant correlation coefficient was obtained between the amount of particle breakage and dry density of the compacted soil.

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An Empirical Review of Korean Perception for Technological Risks (한국인의 위험인지에 대한 경험적 분석)

  • Chung, Ik-Jae
    • Journal of the Korean Society of Safety
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    • 제22권6호
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    • pp.91-97
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    • 2007
  • A survey of risk perception in Korea was conducted in 2001 with a special emphasis on industrial and technological risks. This article summarizes the characteristics of risk perception in consideration of socio-demographic background of respondents. The survey with sample size of 1,870 evaluates the perceived level of 25 risk items in the areas of transportation, chemicals, environment, industry, and nuclear power generation. Risks are categorized by using factor analysis to clarify attitudinal or behavioral properties of risk perception. Research findings show that the level of perceived risk does not correspond to the statistical level. Socio-demographic variables are significant predictors in explaining risk perception, or the discrepancies between "subjective" and "objective" risks. Effective risk communication can reduce the perceptional discrepancies, improve the awareness of technological risks, and ultimately facilitate the process of making and implementing policies for risk management and safety regulation. This article tries to provides policy guidelines for "Who is the target for risk communication" and "Which risk has the policy priority for safety improvement." Married females at the age of 30s and 40s with lower education and lower income in small cities are more vulnerable to risk misperception than other groups. More information and knowledge regarding unfamiliar, intangible, new technological risks should be delivered to the vulnerable groups for reducing perceptional bias. Society-wide safety can be improved by integrating policy, human, and social factors as well as techno-engineering advances.

Effectiveness of school counseling based on "the AMPQ-II and administrative manual": Focusing on the counselor and the number of session factors ("AMPQ-II 및 관리 매뉴얼"에 따른 학교 상담의 효과: 상담자 요인 및 회기 수를 중심으로)

  • Seul, Ji Won;Kim, Geunyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • 제16권2호
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    • pp.978-986
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    • 2015
  • The Korean government has administered the 'AMPQ-II' to all middle school students to prevent psychological problems and make immediate interventions when necessary. On the other hand, there has been a paucity of studies of the effectiveness of this governmental policy, or the factors influencing the effectiveness of the intervention. Using the data from 48 counselees from two middle schools, the present study examined the effectiveness of the intervention programs, and whether the counselor's characteristics and the number of counseling sessions might matter in the effect. The results suggested that most students reported improvements after the interventions. The intervention effect was less pronounced when the counselors had governmental certification. The number of counseling sessions was not a significant factor for predicting the effectiveness of the interventions. Interpretations of the present study should be made cautiously because of the small sample size. The present results, however, suggest that efforts to improve the quality of the counseling teachers are necessary. In addition, increasing the number of counseling sessions is not necessarily effective.

A Robust Hand Recognition Method to Variations in Lighting (조명 변화에 안정적인 손 형태 인지 기술)

  • Choi, Yoo-Joo;Lee, Je-Sung;You, Hyo-Sun;Lee, Jung-Won;Cho, We-Duke
    • The KIPS Transactions:PartB
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    • 제15B권1호
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    • pp.25-36
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    • 2008
  • In this paper, we present a robust hand recognition approach to sudden illumination changes. The proposed approach constructs a background model with respect to hue and hue gradient in HSI color space and extracts a foreground hand region from an input image using the background subtraction method. Eighteen features are defined for a hand pose and multi-class SVM(Support Vector Machine) approach is applied to learn and classify hand poses based on eighteen features. The proposed approach robustly extracts the contour of a hand with variations in illumination by applying the hue gradient into the background subtraction. A hand pose is defined by two Eigen values which are normalized by the size of OBB(Object-Oriented Bounding Box), and sixteen feature values which represent the number of hand contour points included in each subrange of OBB. We compared the RGB-based background subtraction, hue-based background subtraction and the proposed approach with sudden illumination changes and proved the robustness of the proposed approach. In the experiment, we built a hand pose training model from 2,700 sample hand images of six subjects which represent nine numerical numbers from one to nine. Our implementation result shows 92.6% of successful recognition rate for 1,620 hand images with various lighting condition using the training model.