• Title/Summary/Keyword: Time trend analysis

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Study on Demand Estimation of Agricultural Machinery by Using Logistic Curve Function and Markov Chain Model (로지스틱함수법 및 Markov 전이모형법을 이용한 농업기계의 수요예측에 관한 연구)

  • Yun Y. D.
    • Journal of Biosystems Engineering
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    • v.29 no.5 s.106
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    • pp.441-450
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    • 2004
  • This study was performed to estimate mid and long term demands of a tractor, a rice transplanter, a combine and a grain dryer by using logistic curve function and Markov chain model. Field survey was done to decide some parameters far logistic curve function and Markov chain model. Ceiling values of tractor and combine fer logistic curve function analysis were 209,280 and 85,607 respectively. Based on logistic curve function analysis, total number of tractors increased slightly during the period analysed. New demand for combine was found to be zero. Markov chain analysis was carried out with 2 scenarios. With the scenario 1(rice price $10\%$ down and current supporting policy by government), new demand for tractor was decreased gradually up to 700 unit in the year 2012. For combine, new demand was zero. Regardless of scenarios, the replacement demand was increased slightly after 2003. After then, the replacement demand is decreased after the certain time. Two analysis of logistic owe function and Markov chain model showed the similar trend in increase and decrease for total number of tractors and combines. However, the difference in numbers of tractors and combines between the results from 2 analysis got bigger as the time passed.

Analysis of Trends in Housing Culture Until the Recent Year Since 1980s - Focused on the keywords of previous researches - (1980년대 이후 최근까지 주거문화에 관한 연구 경향 분석 - 선행연구의 주제어를 중심으로 -)

  • Kim, Young-Joo;Lee, Soo-Min;Kim, Eun-Bin;Park, Soo-Yeon
    • Korean Institute of Interior Design Journal
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    • v.22 no.4
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    • pp.104-112
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    • 2013
  • Housing culture can be defined as a subculture that characterizes a society, a region, and a time period. Therefore, identifying the housing needs of people is an effective way of understanding the housing culture. The purpose of this study was to identify the research trend of housing culture since 1980s until the recent year based on the keywords of previous literature. Seventy-one research articles were analyzed using content analysis as a research method and analysis framework which was composed of 4 aspects - physical, social, psychological, and living/welfare - was drawn for further analysis. As a main result, housing needs in social and living/welfare aspect were increasing as time passes. In general, researches related to physical aspect showed the highest ratio among 4 aspects. Specifically, research interests in community and social relationship among neighbors, natural environment, and housing welfare has remarkably increased since 2000s. The findings of this study showed that the housing culture is the comprehensive result or the process reflecting the needs and context in political, social, and economical background of those days.

Analysis on Efficiency and Productivity Changes of Regional Public Hospitals in Korea with Data Envelopment Analysis/Window and Global Malmquist Indices Models (Data Envelopment Analysis/Window 모형과 Global Malmquist 생산성지수 모형을 이용한 지방의료원의 효율성과 생산성 변화 분석)

  • Yang, Dong Hyun
    • Health Policy and Management
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    • v.23 no.1
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    • pp.78-89
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    • 2013
  • This study empirically analyze efficiency and productivity changes of public hospitals of Korea using data envelopment analysis/Window model and global Malmquist indices model. We use the ten-year data from 2001 to 2010 of 30 regional public hospitals listed database from the Association of Korean Regional Public Hospitals. The main focuses are to reveal whether the technical inefficiency are improved as time goes by, and efficiency and productivity are affected by environmental factors. The results can be summarized as follows. First, the efficiencies of public hospitals rise in trend as time passes. Second, regional public hospitals show the different average efficiencies according to their regional type, hospital type, operational type, medicaid type, and demand and supply conditions by Mann-Whitney U-tests. Third, technical efficiency changes mainly contribute to 4.4% annual average growth rate of productivity of regional public hospitals during that period. Our findings have some policy implications. It is confirmed that there exist some environmental inefficiencies, and those inefficiencies can not be overcome through just improving the inner management system. Thus, policy and institutional changes are necessary for regional public hospitals to improve efficiency and productivity overall.

A time-domain analysis for a nonlinear free-surface problem (시간영역에서의 비선형 자유표면파문제에 대한 수치해석)

  • Kyoung Jo Hyun;Bai Kwang June;Chung Sang Kwon;Kim Do Young
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.381-384
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    • 2002
  • The free surface flow problem has been one of the most interesting and challenging topic in the area of the naval ship hydrodynamics and ocean engineering field. The problem has been treated mainly in the scope of the potential theory and its governing equation is well known Laplace equation. But in general, the exact solution to the problem is very difficult to obtain because of the nonlinearlity of the free surface boundary condition. Thus the linearized free surface problem has been treated often in the past. But as the computational power increases, there is a growing trend to solve the fully nonlinear free surface problem numerically. In the present study, a time-dependent finite element method is developed to solve the problem. The initial-boundary problem is formulated and replaced by an equivalent variational formulation. Specifically, the computations are made for a highly nonlinear flow phenomena behind a transom stern ship and a vertical strut piercing the free surface.

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Model Misspecification in Nonstationary Seasonal Time Series

  • Sung K. Ahn;Park, Young J.;Cho, Sin-Sup
    • Journal of the Korean Statistical Society
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    • v.27 no.1
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    • pp.67-90
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    • 1998
  • In this paper we analytically study model misspecification that arises in regression analysis of nonstationary seasonal time series. We assume the underlying data generating process is a seasonally or a regularly and seasonally integrated process. We first study consequences of totally misspecified cases where seasonal indicator variables, a linear time trend, or another statistically independent seasonally integrated process are used as predictor variables in order to model the nonstationary seasonal behavior of the dependent variable. Then we study consequences of partially misspecified cases where the dependent variable and a predictor variable are cointegrated at some, but not all of the frequencies corresponding to the nonstationary roots.

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Development of Portable Atmospheric Environment Measurement System using Low Power Wireless Communication

  • Chae, Soohyeon;Kim, Hack-Yoon;Gim, Jangwon
    • Journal of Advanced Information Technology and Convergence
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    • v.10 no.1
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    • pp.99-109
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    • 2020
  • As environmental pollution has become severe due to the rapid increase in pollutant generation in the air, measurement, collection, and analysis of atmospheric environment information plays an important role. However, it is difficult to measure the high-resolution and real-time atmospheric environment of the cities and tourist spots with high population mobility only by measuring equipment of stationary measuring stations. Therefore, this paper proposes a portable atmospheric environment measurement system for real-time measurement and monitoring of atmospheric environment information. The proposed system is a portable client with a low-power wireless communication method. It is possible to reliably transmit and receive the measured data through a multi-threaded server to monitor the trend of pollutants in the air in real-time.

Quantitative Analysis of Silanization Degree of Silica Nanoparticles Modified with Bis[3-(trimethoxysilyl)propyl]amine Coupling Agent (Bis[3-(trimethoxysilyl)propyl]amine 커플링제로 개질된 실리카 나노입자의 실란화도 정량 분석)

  • Jeon, Ha-Na;Kim, Jung-Hye;Ha, Ki-Ryong
    • Polymer(Korea)
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    • v.36 no.3
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    • pp.372-379
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    • 2012
  • In this study, we treated silica nanoparticles with bis[3-(trimethoxysilyl)propyl]amine (BTMA) silane coupling agent to modify their surfaces. We investigated the effects of BTMA hydrolysis time, BTMA concentration and BTMA treatment time on the degree of silanization reaction of silica nanoparticles. We used Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and solid state cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance spectroscopy (NMR) to obtain quantitative data. We found the decrease of isolated Si-OH peak intensity at 3747 $cm^{-1}$ and the increase of $-CH_2 $stretching and bending peaks with increasing hydrolysis time, concentration and treatment time of BTMA. EA analysis results also supported this trend. We found a strong effect of BTMA concentration on the degree of silanization of the silica particles, but weak effects of the hydrolysis time and the treatment time.

A study on of Magdalens Abakanowicz (Magdalena Abakanowicz의 조형분석연구)

  • Ghim Eon-Bae
    • Journal of Science of Art and Design
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    • v.6
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    • pp.203-225
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    • 2004
  • We are sure that Abakanowicz positively assumes a position of members, which are represented the later modern fabric design. In sprite of his pervasive evaluation, we have doubt about his achievement because the preceding research is insufficient about argumentsuch as dependence on intuitive emotion study, conventional analysis of structure and insufficient inquiry of causa efficiens. We agree that basic structure of is dissipation. Though right and left symmetrical structure is similar, also that structure is different. We can't decide whether structure is unification structure, difference structure or mixture structure . We think that the time of confusing argument of his structure is changing period for disorganization trend. The result of this study confirm the research possibility about space organization with restructure analysis and verification for examining essence structure of sample text . The Thesis are concern that the different between paradigmatic appearances and syntagmatic, which exist . So, we can approach the meaning of system and find dominent point about constructional relationship on the works. The meaning of dominent point is understood about sexless trend or Androgyne, which are appeared Abakanowicz forth work period. The relationship structure which is mixed both issue show that inner issue of work is located the highest position. The paper presents confusing manufacture system, which are suggested man-woman sex and mixed meaning. The other result of this study are, 1. being known as Abakan algorism, Abakanowicz has new drafting idiom from his ancient belief. 2. we need to research the body texture of Abakanowicz with the trend of restructure of body study. 3. we need argue about gender study in relative with poster moderntheology related problem of sexlessness people and perfect sex-people.

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A study on custom Hanbok design through on-line review - From 2016 To 2017 - (온라인 후기를 통한 맞춤 웨딩한복의 디자인 고찰 2016년~2017년)

  • Ryu, Kyoung-ok
    • Journal of the Korea Fashion and Costume Design Association
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    • v.20 no.3
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    • pp.27-32
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    • 2018
  • Hanbok is a our own history and tradition and is an icon of Korean history and culture. Today, the costumes are moving around the world fashion trend due to the development of mass media and internet at the same time. This is an important clue to marketing activities and can be used for predictive analysis. Although Hanbok is changing little by little every year, research on the trend of Hanbok is rare. This study analyzed the results of searching for 'Hanbok' as a keyword in Portal Site Naver and posting a customized purchase of Hanbok for marriage between 2016 and 2017. The analysis was based on analyzing the photos uploaded, and analyzing purchase reason in the On-line review. Most buyer of Hanbok purchased for prepare marriage. The choice of a customized hanbok is mostly to search online or to use the fair. The most important factor in choosing a custom Hanbok that appeared in online reviews is color and then price. The color of the jacket is mostly light color and the off-white color is the most used and the long skirt such as the pink system, the chorale system and the red system, and it can be seen that the pink skirt is overwhelmingly large. In the design of Hanbok, The sleeves were straight and narrow, and the length was the chest line. The collar were enlarged and widened. 고름 used the sole color instead of the jacket and skirt color, and it was narrow not long. skirt's pleats was wide, and designed to overlap with double color of the fabric.

Trend Analysis of Technical Terms Using Term Life Cycle Modeling (용어 활용주기 모델링을 이용한 기술용어 트렌드 분석)

  • Hwang, Mi-Nyeong;Cho, Min-Hee;Hwang, Myung-Gwon;Jeong, Do-Heon
    • The KIPS Transactions:PartD
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    • v.18D no.6
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    • pp.493-500
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    • 2011
  • The trends of technical terms express the changes of particular subjects in a specific research field over time. However, the amount of academic literature and patent data is too large to be analyzed by human resources. In this paper, we propose a method that can detect and analyze the trends of terms by modeling the life cycle of the terms. The proposed method is composed of the following steps. First, the technical terms are extracted from academic literature data, and the TDVs(Term Dominance Values) of terms are computed on a periodic basis. Based on the TDVs, the life cycles of terms are modeled, and technical terms with similar temporal patterns of the life cycles are classified into the same trends class. The experiments shown in this paper is performed by exploiting the NDSL academic literature data maintained by KISTI.