• Asian-Australasian Journal of Animal Sciences
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• v.24 no.2
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• pp.295-302
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• 2011

Almost half of New Zealand's greenhouse gas emissions arise from agriculture and enteric methane ($CH_4 $) emissions arising from ruminant animals constitute 30% of total $CO_2$-e emissions. Enteric $CH_4$ emissions have increased by 9% since 1990. Extensive research has been undertaken to develop reliable methods for measuring enteric $CH_4$ emissions. New Zealand studies using the SF6 tracer technique suggest that on average this technique yields similar values to the 'gold' standard of calorimetry, but with a larger variance. National inventory estimates based on results obtained using the $SF_6$ technique will therefore overestimate the uncertainty. Mitigating emissions can be achieved by changing feed type but there are practical and cost barriers to the use of alternative feeds. Forages containing condensed tannins do reduce emissions but are agronomically inferior to the forages currently used. Rumen additives have shown some success in-vitro but results from in-vivo trials with both monensin and fumaric acid have been disappointing. The development of methods for directly manipulating rumen microorganisms are at an early stage and work to develop vaccines that can inhibit methanogenesis has yielded mixed results. The successful identification of sheep with contrasting $CH_4$ yields raises the possibility that, in the long term, a breeding approach to $CH_4$ mitigation is feasible.

• The Journal of Korean Medicine
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• v.25 no.1
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• pp.142-151
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• 2004

Objectives : To document the use and out-of-pocket expenditure of complementary and alternative medicine(CAM) in Korean adult population. Methods : Nationwide, random-sampled, and population-weighted telephone survey was conducted. The sample size of respondents was 1,000(age over 18). The respondents were asked about their use, out-of pocket expenditure of CAM in the past 12 months. SAS 8.0 statistic package was used for checking the relevance between each variables by performing $x^2-test$ and variance evaluation. Results : In 2001, 64.0% of people experienced more than one alternative therapy and the beneficiary took therapy average figure of 2.07. Alternative therapies were generally used for health promotion(73.7%) rather than curing the disease(26.3%). The most common therapies included Medication(30.2%), Physical-therapy(21.9%) health implements(20.8%), herb medication(19.2%), diet therapy(14.3%) etc. Average annual out-of-pocket expenditure was ￡<192,186. Use varied according to age, living province, income, and education, while cost expenditure did according to sex, health condition, income, education. Conclusions : The use of CAM in Korea is very large and the expenditure for them is 22.6% of national medical expenditure. It shows great need of political and academic approach.

• Journal of the Korean Operations Research and Management Science Society
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• v.37 no.3
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• pp.135-150
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• 2012

This paper presents a portfolio model for a long-term power generation mix problem. The proposed portfolio model evaluates generation mix by considering the tradeoffs between the expected cost for power generation and its variability. Unlike conventional portfolio models measuring variance, we introduce Conditional Value-at-Risk (CVaR) in designing the variability with aims to considering events that are enormously expensive but are rare such as nuclear power plant accidents. Further, we consider uncertainties associated with future electricity demand, fuel prices and their correlations, and capital costs for power plant investments. To obtain an objective generation by each energy source, we employ the sample average approximation method that approximates the stochastic objective function by taking the average of large sample values so that provides asymptotic convergence of optimal solutions. In addition, the method includes Monte Carlo simulation techniques in generating random samples from multivariate distributions. Applications of the proposed model and method are demonstrated through a case study of an electricity industry with nuclear, coal, oil (OCGT), and LNG (CCGT) in South Korea.

• Korean Journal of Computational Design and Engineering
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• v.18 no.5
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• pp.359-366
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• 2013

In the lower arm design process, a tolerance optimization of the variance of design variables should be preceded before manufacturing process, since it is very cost-effective compared to a strict management of tolerance of products. In this study, a design of experiment (DOE) based on response surface model (RSM) was carried out to find optimized design variables of the lower arm, which can meet a given requirement of probability constraint for the process capability index (Cpk) of the weight and maximum stress. Then, the design space was explored by using the central composite design method, in which the 2nd order Taylor expansion was applied to predict a standard deviation of the responses. The optimal solutions satisfying the probability constraint of the Cpk were found by considering both of the mean value and the standard deviation of the design variables.

• Journal of Construction Engineering and Project Management
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• v.3 no.4
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• pp.5-11
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• 2013

Construction industry is overwhelmed by delay and often has suffered cost and time overrun. In this context, Last Planner System (LPS) has been considered as a very useful tool for the management of the construction process. Many previous studies have reported its effectiveness in construction performance. This study aims to evaluate the level of importance of the Last Planner processes in the Vietnam construction industry (VCI), and analyze the existing barriers when implementing these processes in construction management. These barriers were collected based on previous studies from International Group for Lean Construction (IGLC). A survey was carried out through questionnaire. The respondents are been experienced people in construction project management. There are four processes of LPS that were investigated including master schedule, phase schedule, lookahead plan, and weekly work plan. The results showed that master schedule is the most important item when performing a construction project in the VCI. The highest degree of agreement belongs to 'owner - contractor' pair with 77.1% importance indices; whereas the lowest belongs to 'consultants - contractors' pair with 63.8% importance indices. Eventually, three barrier factors were extracted from factor analysis technique with 62.2% of variance explained.

• Journal of Construction Engineering and Project Management
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• v.3 no.4
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• pp.20-25
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• 2013

Variation in construction means modification of design, changes in quality, quantity of work including the alteration of standard of materials or goods to be used in the work and the removal from site any kind of material not in accordance in the contract. In Ghana, Variation order has become major issue in the construction industry. This had resulted in cost overruns, delay and in some contracts dispute, between parties. The aim of this paper was to identify the root causes of variation; effects of variations on projects in Ghana and the means of reducing the impact of variation order. The method of the study involved literature review, primary data collection, interview and closed - ended- questionnaires. Mean Scores Method was used to rank the identified factors causing variation. Analysis Of Variance Test was use to test for the significant difference between means among the professional groups. The study revealed that most causes of variation were change of design by client and inadequate working details. Establishment of oversight project management committee and flow of information were identified as means of controlling variations during project administration.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.73-80
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• 2006

High speed machining(HSM) technique is widely used in the appliance, automobile part and mold industries, because it has many advantages such as good quality, low cost and rapid machining time. But it also has problems such as tool breakage, smooth tool path, and so on. In particular, small size end mill is easy to break, so it must be changed before interrupting operation. Generally, the tool life of small size end mill is affected by the milling conditions whose selected parameters are spindle speed, feedrate, and width of cut. The experiments were carried out by full factorial design of experiments using an orthogonal array. This paper shows optimal combination and mathematical model for tool life, Therefore, the analysis of variance(ANOVA) is employed to analyze the main effects and the interactions of these milling parameters and the second-order polynomial regression model with three independent variables is estimated to predict tool life by multiple regression analysis.

• Korean Journal of Environmental Agriculture
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• v.33 no.1
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• pp.37-43
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• 2014

BACKGROUND: Water quality data are collected less frequently than flow data because of the cost to collect and analyze, while water quality data corresponding to flow data are required to compute pollutant loads or to calibrate other hydrology models. Regression models are applicable to interpolate water quality data corresponding to flow data. METHODS AND RESULTS: A regression model was suggested which is capable to consider flow and time variance, and the regression model coefficients were calibrated using various measured water quality data with genetic-algorithm. Both LOADEST and the regression using genetic-algorithm were evaluated by 19 water quality data sets through calibration and validation. The regression model using genetic-algorithm displayed the similar model behaviors to LOADEST. The load estimates by both LOADEST and the regression model using genetic-algorithm indicated that use of a large proportion of water quality data does not necessarily lead to the load estimates with smaller error to measured load. CONCLUSION: Regression models need to be calibrated and validated before they are used to interpolate pollutant loads, as separating water quality data into two data sets for calibration and validation.

• Journal of the Korean Home Economics Association
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• v.41 no.12
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• pp.133-146
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• 2003

This study was aimed to classify the consumer group according to the lifestyle, to research the characteristics and desire of the each group, and to find out the differences of the purchasing behavior of cosmetics among each group. After surveying, 611 samples were analyzed by using SPSS package program. The results of this study were as follows；1. We obtained 5 factors from 21 items by using AIO lifestyle measurement. Those 5 factors were personalityㆍmake-up preference, arance-oriented, economy and information-oriented, daily make-up, and interest in make-up. 2. We formed 4 groups from the 5 factors. Which are a make-up oriented group, a consciously daily make-up group, a unconcern of make-up group, and a resonable make-up pursuit group. 3. The demographic characteristics of each lifestyle group showed important differences according to the following variables; age, marital status, occupation, academic career and monthly averaged income. 4. We analyzed the purchase behavior, the purchase motive of make-up, the brand of cosmetics, the reason for preferring company, purchase information, product store, the reason for choosing store, important considering points, monthly averaged purchase cost. As a result, its variance showed the difference among groups.

• Journal of Nutrition and Health
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• v.36 no.10
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• pp.1061-1070
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• 2003

The purpose of this study was to investigate differences in the diet with the amount and the qualitative assessment of nutrient intakes by the economic level. Data from the 1998 Korean Health and Nutrition Survey were used. Using the poverty line based on the 1998 Korean minimum cost of living, Subjects (n = 10400) were classified into high class (36.1％), middle class (40.7％) and low class (23.1％). Chi-square-test and Analysis of Variance following Duncan's multiple range test were used to test the difference in nutrient intake pattern among three groups ($\alpha$ = 0.05). The amount of nutrient intake and nutrient intake adequacy were statistically different by the economic level (p<0.01). The ratio of energy intake from carbohydrate is higher than the criteria of WHO recommendation in all economic levels. Especially people in the low class depended much on the carbohydrate for the energy intake. The ratio of energy from the protein and fat are lower in the middle and low class than that of the high class. The Intake level of calcium and vitamin B$_2$ were lower than those of the Recommended Dietary intake level, regardless of economic status. It also showed differences in major food sources of nutrients by the economic level Consequently, it seems that the nutrition policy and program should be prepared according to their economic status. Also, there should more detailed studies to find out the nutrient intake pattern, their determinant, and health consequences.