• Title/Summary/Keyword: Fixed-Effects

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Estimable functions of fixed-effects model by projections (사영에 의한 모수모형의 추정가능함수)

  • Choi, Jae-Sung
    • Journal of the Korean Data and Information Science Society
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    • v.23 no.3
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    • pp.487-494
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    • 2012
  • This paper discusses a method for getting a basis set of estimable functions of model parameters in a two-way fixed effects model. Since the fixed effects model has more parameters than those that can be estimated, model parameters are not estimable. So it is not possible to make inferences for nonestimable functions of parameters. When the assumed model of matrix notation is reparameterized by the estimable functions in a basis set, it also discusses how to use projections for the estimation of estimable functions.

The Impact of Trade Openness on Economic Growth: Evidence from Agricultural Countries

  • SIREGAR, Abi Pratiwa;WIDJANARKO, Nadila Puspa Arum
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.3
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    • pp.23-31
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    • 2022
  • The study investigates the effect of trade openness on the economic growth of agricultural countries. The information of export, import, gross domestic product (GDP), Gross Fixed Capital Formation (GFCF), and population of 72 agrarian nations generated by the World Bank from 2011 until 2020 is used for data examination. Then, before panel data analysis, a preferred model is chosen from among common-effects, fixed-effects, and random effects. The best model turns out to be a fixed-effect model. The result reports that from 2011 to 2020; 16 out of 72 nations have succeeded in experiencing positive economic growth, the value of GFCF was US$ 2,859.04 billion, and later grew by 19 percent to US$ 3,393.73 billion, the population tends to increase continuously year by year, and 2 out of 72 countries experienced export plus import exceed their GDP. Moreover, trade openness is positively associated with economic growth, with a coefficient of 3.81. Besides that, an increase in GFCF may boost economic growth by approximately 3.32 percent. On the contrary, one percent additional population significantly delivers around 25.46 percent negative economic growth. To sum up, the higher intensity of products or services sold and bought abroad may enhance the economic performance.

Variance Components and Genetic Parameters for Milk Production and Lactation Pattern in an Ethiopian Multibreed Dairy Cattle Population

  • Gebreyohannes, Gebregziabher;Koonawootrittriron, Skorn;Elzo, Mauricio A.;Suwanasopee, Thanathip
    • Asian-Australasian Journal of Animal Sciences
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    • v.26 no.9
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    • pp.1237-1246
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    • 2013
  • The objective of this study was to estimate variance components and genetic parameters for lactation milk yield (LY), lactation length (LL), average milk yield per day (YD), initial milk yield (IY), peak milk yield (PY), days to peak (DP) and parameters (ln(a) and c) of the modified incomplete gamma function (MIG) in an Ethiopian multibreed dairy cattle population. The dataset was composed of 5,507 lactation records collected from 1,639 cows in three locations (Bako, Debre Zeit and Holetta) in Ethiopia from 1977 to 2010. Parameters for MIG were obtained from regression analysis of monthly test-day milk data on days in milk. The cows were purebred (Bos indicus) Boran (B) and Horro (H) and their crosses with different fractions of Friesian (F), Jersey (J) and Simmental (S). There were 23 breed groups (B, H, and their crossbreds with F, J, and S) in the population. Fixed and mixed models were used to analyse the data. The fixed model considered herd-year-season, parity and breed group as fixed effects, and residual as random. The single and two-traits mixed animal repeatability models, considered the fixed effects of herd-year-season and parity subclasses, breed as a function of cow H, F, J, and S breed fractions and general heterosis as a function of heterozygosity, and the random additive animal, permanent environment, and residual effects. For the analysis of LY, LL was added as a fixed covariate to all models. Variance components and genetic parameters were estimated using average information restricted maximum likelihood procedures. The results indicated that all traits were affected (p<0.001) by the considered fixed effects. High grade $B{\times}F$ cows (3/16B 13/16F) had the highest least squares means (LSM) for LY ($2,490{\pm}178.9kg$), IY ($10.5{\pm}0.8kg$), PY ($12.7{\pm}0.9kg$), YD ($7.6{\pm}0.55kg$) and LL ($361.4{\pm}31.2d$), while B cows had the lowest LSM values for these traits. The LSM of LY, IY, YD, and PY tended to increase from the first to the fifth parity. Single-trait analyses yielded low heritability ($0.03{\pm}0.03$ and $0.08{\pm}0.02$) and repeatability ($0.14{\pm}0.01$ to $0.24{\pm}0.02$) estimates for LL, DP and parameter c. Medium heritability ($0.21{\pm}0.03$ to $0.33{\pm}0.04$) and repeatability ($0.27{\pm}0.02$ to $0.53{\pm}0.01$) estimates were obtained for LY, IY, PY, YD and ln(a). Genetic correlations between LY, IY, PY, YD, ln(a), and LL ranged from 0.59 to 0.99. Spearman's rank correlations between sire estimated breeding values for LY, LL, IY, PY, YD, ln(a) and c were positive (0.67 to 0.99, p<0.001). These results suggested that selection for IY, PY, YD, or LY would genetically improve lactation milk yield in this Ethiopian dairy cattle population.

A Study for Princess Line according to Body Type II - Focused on Body Type of H & Y - (체형에 따른 프린세스 라인 연구 II - H 체형과 Y 체형을 중심으로 -)

  • 김숙정;서미아
    • The Research Journal of the Costume Culture
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    • v.9 no.6
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    • pp.893-907
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    • 2001
  • The main purpose is to study the effects of princess lines on different body types and to disguise any imperfection by using diverse princess lines. We separated testers body shapes into specific body types, H, Y by applying both the direct and the indirect measurements. These designs were evaluated by using the point ranking system method, and then average scores were obtained from these evaluations. Following are the results of the study: 1 These are the resulting illusion effects when the shoulder width of the Princess line was fixed. When the Princess line originated from 1/3 point of the armhole, body types Y appeared to show narrow waist width. A-line silhouette appeared to display the narrowest shoulder width. When the Princess line originated from 2/3 point of the armhole, body types H and Y appeared to exhibit narrowest waist widths, and the A-line silhouette once again displayed the narrowest shoulder width. When the Princess line originated from 1/2 point of the armhole, body type H appeared to exhibit narrow width; and H-line silhouette displayed the narrowest shoulder width 2. When the Princess lines waist w'4th was fixed in order to study illusion effects of waist widths. In this experiment, locations of Princess lines and widths of the skirt were varied. When the waist width was fixed at 6.5 cm, For the H body type, the Princess line location of 1/3 point of the armhole in H-line silhouette design exhibited the narrowest waist width. For the Y body type in A-line silhouette design, the Princess line locations of 1/3 and 1/2 points of the armhole exhibited the narrowest waist width because it displayed the hourglass effect. When the waist width was fixed at 10 cm, H body type did not exhibit any significant differences between designs. For Y body type, A-line silhouette design with the Princess line origination point at 1/3 down the armhole exhibited the narrowest waist width. 3. The illusion effects of the hip were studied by fixating the width of the skirt and varying the locations of Princess line and waist widths. In H-line skirt silhouette designs, all two body types exhibited narrow hips when the Princess line origination points were at 1/3 and 1/2 way down the armhole. For A-line skirt silhouette, H body type exhibited narrow hips when narrow waist design with the Princess line originating from 1/2 point in the shoulder was shown. Y body type exhibited narrow hips when narrow waist design with the Princess line originating from 1/3 point of the armhole and 2/3 point of the shoulder. 4. With both waist and skirt widths fixed, all two body types exhibited taller and slender postures when the Princess line originated from the shoulder compare to the armhole.

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Analysis of Breakthrough Curves and Mass Transfer Resistance for Phenol Adsorption in a Fixed-bed Process Packed with Activated Carbon (활성탄을 충전한 고정층에서 페놀 흡착에 따른 파과곡선과 물질전달저항 해석)

  • You, Hae-Na;Kam, Sang-Kyu;Lee, Min-Gyu
    • Journal of Environmental Science International
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    • v.23 no.1
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    • pp.53-60
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    • 2014
  • Adsorption of phenol on activated carbon in a fixed bed was studied. The effects of fixed-bed length, superficial velocity (flow rate) and particle size of adsorbent on fixed-bed performance were investigated. Some characteristic parameters such as the breakthrough time ($t_{0.05}$), saturation time ($t_{0.95}$), length of mass transfer zone ($L_{MTZ}$), adsorptive capacity (W), and adsorption rate constant ($K_a$) were derived from the breakthrough curves. Adsorbent particle sizes significantly affected the shape of the breakthrough curve. Larger particle sizes resulted in an earlier breakthrough, a longer $L_{MTZ}$ and a lower adsorption rate. Superficial velocity was a critical factor for the external mass transfer during fixed-bed adsorption process. The external mass transfer resistance was dominant as increasing superficial velocity.

Effects of Fixed-intensity and Varied-intensity Electroacupuncture on Heart Rate Variability in Healthy People with Stress Task (고정자극 전침과 변동자극 전침의 정상인 스트레스에 대한 심박변이도 변화 연구)

  • Lim, Sung-Keun;Lee, Dong-Hua;Kwon, You-Jung;Lee, Jeung-Chan;Jung, Chang-Jin;Kim, Yong-Suk;Park, Kyung-Mo;Lee, Sang-Hoon
    • Journal of Acupuncture Research
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    • v.28 no.2
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    • pp.107-116
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    • 2011
  • Objectives : This study was performed to investigate the effects of fixed-intensity and varied-intensity electroacupuncture on heart rate variability in healthy people with stress task. Methods : Forty healthy subjects were randomly assigned to either group A or group B or C. Group A received fixed-intensity electroacupuncture(F-EA) at $ST_{36}$ and $ST_{37}$. After 1 week wash out period to prevent overlapping residual effects, they received varied-intensity electroacupuncture(V-EA) in which the intensity was changed every two minutes based on individual heart rate variability at the same points. Group B received the treatments in reverse order. Group C received no intervention as a control group. Results : Control group showed a significant increase of LF and LF/HF during the 2nd working memory task, while both F-EA and V-EA did not. In addition, V-EA showed a significant increase of HF during 2nd rest while F-EA did not. Conclusions : These results suggest that F-EA and V-EA can inhibit sympathetic activation more than control group and that V-EA can enhance parasympathetic activation more than F-EA.

The Characteristics and Implementations of Quality Metrics for Analyzing Innovation Effects in Six Sigma Projects (식스시그마 프로젝트 사례에서 혁신효과 분석을 위한 품질척도의 특성 및 적용)

  • Choi, Sungwoon
    • Journal of the Korea Safety Management & Science
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    • v.16 no.1
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    • pp.169-176
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    • 2014
  • This research discusses the characteristics and the implementation strategies for two types of quality metrics to analyze innovation effects in six sigma projects: fixed specification type and moving specification type. $Z_{st}$, $P_{pk}$ are quality metrics of fixed specification type that are influenced by predetermined specification. In contrast, the quality metrics of moving specification type such as Strictly Standardized Mean Difference(SSMD), Z-Score, F-Statistic and t-Statistic are independent from predetermined specification. $Z_{st}$ sigma level obtains defective rates of Parts Per Million(PPM) and Defects Per Million Opportunities(DPMO). However, the defective rates between different industrial sectors are incomparable due to their own technological inherence. In order to explore relative method to compare defective rates between different industrial sectors, the ratio of specification and natural tolerance called, $P_{pk}$, is used. The drawback of this $P_{pk}$ metric is that it is highly dependent on the specification. The metrics of F-Statistic and t-Statistic identify innovation effect by comparing before-and-after of accuracy and precision. These statistics are not affected by specification, but affected by type of statistical distribution models and sample size. Hence, statistical significance determined by above two statistics cannot give a same conclusion as practical significance. In conclusion, SSMD and Z-Score are the best quality metrics that are uninfluenced by fixed specification, theoretical distribution model and arbitrary sample size. Those metrics also identify the innovation effects for before-and-after of accuracy and precision. It is beneficial to use SSMD and Z-Score methods along with popular methods of $Z_{st}$ sigma level and $P_{pk}$ that are commonly employed in six sigma projects. The case studies from national six sigma contest from 2011 to 2012 are proposed and analyzed to provide the guidelines for the usage of quality metrics for quality practitioners.

Long-term effects of chlorhexidine varnish treatment on microbial changes of dental plaque in orthodontic patients with fixed appliances (Chlorhexidine varnish 처치 후 고정식 교정장치 장착 환자의 치태내 균주 변화 양상에 대한 장기간 관찰 연구)

  • Chang, Young-Il;Yang, Won-Sik;Nahm, Dong-Seok;Kim, Tae-Woo;Baek, Seung-Hak
    • The korean journal of orthodontics
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    • v.30 no.3 s.80
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    • pp.335-342
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    • 2000
  • The authors observed the long term effects of chlorhexidine varnish treatment on microbial change of dental plaque in orthodontic patients with fixed appliances. The initial sample was 100 patients who were arranged to be treated with fixed orthodontic appliances. The final sample consisted of 21 patients who could be traced for 32 weeks after application of fixed orthodontic appliances. They were classified into the experimental group (12 patients) and the control group (9 patients). The experimental group was treated with chlorhexidine varnish once a week for 4 weeks before application of fixed orthodontic appliance. The control group was not treated with chlorhexidine varnish before application of fixed orthodontic appliance. The experimental group was treated once more after 20 weeks. The microbial changes of dental plaque were analysed by indirect immunofluorescence technique at pre-treatment, post-treatment 4, 8, 20, and 32 weeks. The results were as follows. 1. In the experimental group, streptococus mutans was significantly suppressed during experimental period. (p<0.01) But, in the control group, streptococcus mutans was significantly increased after placement of fixed orthodontic appliances during experiment period. (p<0.05) 2. Streptococcus sanguis, Streptococcus mitis, Actinomyces viscosus, md Actinomyces naeslundii did not show significant change between the experimental and the control group during experiment period. So, if we treat the orthodontic patients with chlorhexidine varnish before application of fixed appliances, we may suppress the major cariogenic bacteria, Streptococcus mutans, selectively for long period.

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EFFECTS OF FIXED SPACE MAINTAINER AFTER MISSING OF ANTERIOR TEETH (상악 유전치 조기상실시 고정성 공간유지장치의 효과)

  • Hwang, Dong-Hwan;Choi, Byung-Jai;Choi, Hyung-Jun;Lee, Jae-Ho
    • Journal of the korean academy of Pediatric Dentistry
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    • v.24 no.1
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    • pp.186-194
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    • 1997
  • The three child patients aged 3 to 5 years were worn by anterior space maintainer which are fixed type after missing of anterior teeth due to nursing caries, and were taken periodic follow check up. The results are : 1. At missing of anterior teeth, fixed space maintainer can be used. 2. Increased esthetic satisfaction and positive change of social behavior can be observed by these child patients. 3. Some phonations can be changed definitely after wearing the fixed space maintainer.

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Behavior of symmetrically haunched non-prismatic members subjected to temperature changes

  • Yuksel, S. Bahadir
    • Structural Engineering and Mechanics
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    • v.31 no.3
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    • pp.297-314
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    • 2009
  • When the temperature of a structure varies, there is a tendency to produce changes in the shape of the structure. The resulting actions may be of considerable importance in the analysis of the structures having non-prismatic members. Therefore, this study aimed to investigate the modeling, analysis and behavior of the non-prismatic members subjected to temperature changes with the aid of finite element modeling. The fixed-end moments and fixed-end forces of such members due to temperature changes were computed through a comprehensive parametric study. It was demonstrated that the conventional methods using frame elements can lead to significant errors, and the deviations can reach to unacceptable levels for these types of structures. The design formulas and the dimensionless design coefficients were proposed based on a comprehensive parametric study using two-dimensional plane-stress finite element models. The fixed-end actions of the non-prismatic members having parabolic and straight haunches due to temperature changes can be determined using the proposed approach without necessitating a detailed finite element model solution. Additionally, the robust results of the finite element analyses allowed examining the sources and magnitudes of the errors in the conventional analysis.