• Title/Summary/Keyword: mean-variance model

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The Price Discovery ana Volatility Spillover of Won/Dollar Futures (통화선물의 가격예시 기능과 변동성 전이효과)

  • Kim, Seok-Chin;Do, Young-Ho
    • The Korean Journal of Financial Management
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    • v.23 no.1
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    • pp.49-67
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    • 2006
  • This study examines whether won/dollar futures have price discovery function and volatility spillover effect or not, using intraday won/dollar futures prices, volumes, and spot rates for the interval from March 2, 2005 through May 30, 2005. Futures prices and spot rates are non-stationary, but there is the cointegration relationship between two time series. Futures returns, spot returns, and volumes are stationary. Asymmetric effects on volatility in futures returns and spot returns does not exist. Analytical results of mean equations of the BGARCH-EC (bivariate GARCH-error correction) model show that the increase of futures returns raise spot returns after 5 minutes, which implies that futures returns lead spot returns and won/dollar futures have price discovery function. In addition, the long-run equilibrium relationship between the two returns could help forecast spot returns. Analytical results of variance equations indicate that short-run innovations in the futures market positively affect the conditional variances of spot returns, that is, there is the volatility spillover effect in the won/dollar futures market. A dummy variable of volumes does not have an effect on two returns but influences significantly on two conditional variances.

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Estimation of genetic parameter for carcass traits of commercial steers in Pyeongchang (평창지역 거세출하우 자료를 이용한 유전모수 추정)

  • Dang, Chang-Gwon;Kim, Hyeong-Cheol;Jang, Sun-Sik;Lee, Jeong-Mook;Hong, Yeong-Hun;Jeon, Gi-Jun;Yeon, Seong-Heum;Kang, Hee-Seol;Yang, Bo-Suk;Hong, Seong-Koo;Lee, Jun-Heon;Lee, Seung-Hwan
    • Korean Journal of Agricultural Science
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    • v.40 no.4
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    • pp.339-345
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    • 2013
  • The objective of this study was to establish genetic evaluation systems with carcass data collected by 68 individual farms from 2007 to 2011 in Pyeongchang area of Kangwon province. All the possible of environment effects were corrected by analysis of variance (ANOVA) to estimate more accurate genetic parameters. Heritabilities and genetic correlations were estimated from carcass data collected from Hanwoo steers(n=10,441) born in Pyeongchang region from 2005 to 2008. Traits evaluated included carcass weight (CWT), eye muscle area (EMA), back fat thickness (BF) and marbling score (MS). As for the mean value and standard deviation for carcass traits, CWT, EMA, BF and MS were 424.5, 92, 13.7 and 5.7. Parameters were estimated using a multiple trait animal model and derivative-free restricted maximum likelihood procedures. Estimated heritabilities for CWT, EMA, BF and MS were 0.30, 0.21, 0.42 and 0.42, respectively. Genetic correlation of CWT with EMA, BF and MS were estimated to 0.24, 0.36 and 0.07, respectively. Genetic correlation of EMA with BF and MS was -0.27 and 0.61, respectively.

Decisional balance corresponding to the Stage of Change of Smoking Cessation in Middle Aged Men (중년 흡연남성의 금연 변화단계에 따른 의사결정 균형에 대한 연구)

  • Chang Sung-Ok;Park Chang-Seung;Min In-Sun
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.7 no.2
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    • pp.164-176
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    • 2000
  • Purpose : This study was done to identify the factors of decisional balance for smoking cessation among middle aged men in Korea. This was composed of a set of variables at the level of decision making when middle aged men decide to stop smoking. It was used to classify and identify the characteristics of the stages of change for smoking cessation to which the middle aged men belong, and was used to identify the variables of decisional balance which influenced the stages of change for smoking cessation in middle aged men. Methods : A convenience sample of 169 men who had smoked and were smoking, were between age 30 and 60 and lived in Seoul(mean age=44), were selected from the community. The data was collected from December 10, 1999 to February 28, 2000. The research instrument was the Decisional Balance Measure for Smoking Cessation (Velicer et al., 1985). and Stage of Change Measure(DiClemente et al., 1991). The data were analyzed using the SAS Program. Results : 1. According to stage of change measure, the 169 subjects were distributed in each stage of change for smoking cessation: in the pre-contemplation stage 63 subjects(32.7%), contemplation stage 60 subjects (35.5%), preparation stage 17 subjects(10.1%), and maintenance stage 29 subjects(17.2%). 2. Factor analysis identified 4 factors of decisional balance as appropriate factors for smoking cessation of middle aged men. There were named by the researchers; 1)'Perceived Burden to Self', 2)'Perceived Benefit to Others' 3)'Perceived Approval to Others', and 4)'Perceived Disapproval to Self'. 3. Analysis of variance showed that the three components, 1)'Perceived Burden to Self(F=8.50, P=.0001)', 2)'Perceived Benefit to Others(F=3.19, P=.025)' and 3)'Perceived DisApproval to Self(F=2.87, P=.038)were significantly associated with stage of change. 4. Through discriminant analysis, it was found that 'Perceived Burden to self' was the most influential variable in discriminating the four stages of change(pre-contemplation, contemplation, preparation, and maintenance). Conclusion : The results are consistent with the application of the Transtheoretical model, which has been used to understand how people change health behavior. Even though this study is a cross-sectional, not a longitudinal study, the findings of this study give useful information for smoking cessation intervention for the middle aged men.

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Evaluation of marginal fit of 2 CAD-CAM anatomic contour zirconia crown systems and lithium disilicate glass-ceramic crown

  • Ji, Min-Kyung;Park, Ji-Hee;Park, Sang-Won;Yun, Kwi-Dug;Oh, Gye-Jeong;Lim, Hyun-Pil
    • The Journal of Advanced Prosthodontics
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    • v.7 no.4
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    • pp.271-277
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    • 2015
  • PURPOSE. This study was to evaluate the marginal fit of two CAD-CAM anatomic contour zirconia crown systems compared to lithium disilicate glass-ceramic crowns. MATERIALS AND METHODS. Shoulder and deep chamfer margin were formed on each acrylic resin tooth model of a maxillary first premolar. Two CAD-CAM systems (Prettau$^{(R)}$Zirconia and ZENOSTAR$^{(R)}$ZR translucent) and lithium disilicate glass ceramic (IPS e.max$^{(R)}$press) crowns were made (n=16). Each crown was bonded to stone dies with resin cement (Rely X Unicem). Marginal gap and absolute marginal discrepancy of crowns were measured using a light microscope equipped with a digital camera (Leica DFC295) magnified by a factor of 100. Two-way analysis of variance (ANOVA) and post-hoc Tukey's HSD test were conducted to analyze the significance of crown marginal fit regarding the finish line configuration and the fabrication system. RESULTS. The mean marginal gap of lithium disilicate glass ceramic crowns (IPS e.max$^{(R)}$press) was significantly lower than that of the CAD-CAM anatomic contour zirconia crown system (Prettau$^{(R)}$Zirconia) (P<.05). Both fabrication systems and finish line configurations significantly influenced the absolute marginal discrepancy (P<.05). CONCLUSION. The lithium disilicate glass ceramic crown (IPS e.max$^{(R)}$press) had significantly smaller marginal gap than the CAD-CAM anatomic contour zirconia crown system (Prettau$^{(R)}$Zirconia). In terms of absolute marginal discrepancy, the CAD-CAM anatomic contour zirconia crown system (ZENOSTAR$^{(R)}$ZR translucent) had under-extended margin, whereas the CAD-CAM anatomic contour zirconia crown system (Prettau$^{(R)}$Zirconia) and lithium disilicate glass ceramic crowns (IPS e.max$^{(R)}$press) had overextended margins.

Development a Measurement Scale for Analysis on Factors Influencing College Choice of College Freshman's (전문대학 신입생들의 대학선택 영향 요인 분석을 위한 측정도구 개발)

  • Kim, Myung-Eun;Jang, Won-Seok
    • The Journal of the Korea Contents Association
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    • v.16 no.7
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    • pp.50-62
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    • 2016
  • The aim of this study was to develop scale of test taker to affect on process of selection of college. The study procedures were performed as follow : establish of study model, item generation, verification of content validity, 1st and 2nd pilot test and verification of construct validity and reliability. In order to verification of validity and reliability, 230 freshman were surveyed and the data were analyzed by mean, standard deviation, skewness. kurtosis, Pearson correlation, Verimax factor analysis and Cronbach's ${\alpha}$. As result of factor analysis, the 15 factors(61 items) that explain 68.37% of the total variance were extracted and each factors were classified by attribution as follow : Information collection-mass media(4items), college activity (3items), support and environment(4items), education(5items), Influential person on decision making(3items), education quality(4items), education service(5items), reputation(3items), accessibility(2items), personal circumstances(2items), college's mass media(5items), promotion (4items), on-line(4items), person's PR (3items), College image(10items). Cronbach's ${\alpha}$ of total items was 0.916 and Cronbach's ${\alpha}$ of each factors were showed range between 0.694~0.878. Measurement scale of this study may be utilized to collect basic data be required to establish policy strategy of local college be faced with difficulty of admission recruitment.

Effect of Self-resilience and Professional Self-concept, Major satisfaction on Nursing Student's Adjustment to college life (간호대학생의 자아탄력성, 간호전문직 자아개념, 전공만족도가 대학생활적응에 미치는 영향)

  • Park, Seon-Hwa;Han, Seung-Hee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.8
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    • pp.517-526
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    • 2016
  • The purpose of this study was to investigate the self-resilience, professional self-concept, and major satisfaction on nursing students' adjustment to college life and to present the basic data to assist in healthy adaption of college life. The study included 310 students from two universities in Gwangju and Jeonnam. A questionnaire survey was conducted on the subjects to determine their self-resilience, professional self-concept, major satisfaction, and adjustment to college life with nursing as a major. The data were collected from 1, April, 2016 to 15, April using self-report, questionnaires and analyzed through descriptive statistics, percentage, mean, standard deviation, t-test, ANOVA, and Pearson correlation coefficient, using SPSS 20.0. As a result, self-esteem, professional self-concept, major satisfaction, and adjustment to college life averaged 3.80 (out of 4), 2.81 (4), 3.86 (5), and 2.75 (5) respectively. In terms of correlations, there was a significant positive correlation between adjustment to college life and self-resilience (r=.404, p<.001) and professional self-concept (r=.404, p<.001) and major satisfaction(r=.455, p<.001). In addition, self-resilience (${\beta}=.252$, p<.001) and major satisfaction (${\beta}=.309$, p<.001) of variance in adjustment to college life and the explanatory power of the model was 27.2%. Based on these results, improvement programs are necessary to help nursing students get adjusted to college life.

Fitting accuracy of ceramic veneered Co-Cr crowns produced by different manufacturing processes

  • von Maltzahn, Nadine Freifrau;Bernhard, Florian;Kohorst, Philipp
    • The Journal of Advanced Prosthodontics
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    • v.12 no.2
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    • pp.100-106
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    • 2020
  • PURPOSE. The purpose of this in vitro study was to evaluate the fitting accuracy of single crowns made from a novel presintered Co-Cr alloy prepared with a computer-aided design and computer-aided manufacturing (CAD/CAM) technique, as compared with crowns manufactured by other digital and the conventional casting technique. Additionally, the influence of oxide layer on the fitting accuracy of specimens was tested. MATERIALS AND METHODS. A total of 40 test specimens made from Co-Cr alloy were investigated according to the fitting accuracy using a replica technique. Four different methods processing different materials were used for the manufacture of the crown copings (milling of presintered (Ceramill Sintron-group_cer_sin) or rigid alloy (Tizian NEM-group_ti_nem), selective laser melting (Ceramill NPL-group_cer_npl), and casting (Girobond NB-group_gir_nb)). The specimens were adapted to a resin model and the outer surfaces were airborne-particle abraded with aluminum oxide. After the veneering process, the fitting accuracy (absolute marginal discrepancy and internal gap) was evaluated by the replica technique in 2 steps, before removing the oxide layer from the intaglio surface of the crowns, and after removing the layer with aluminum oxide airborne-particle abrasion. Statistical analysis was performed by multifactorial analysis of variance (ANOVA) (α=.05). RESULTS. Mean absolute marginal discrepancy ranged between 20 ㎛ (group_cer_npl for specimens of Ceramill NPL) and 43 ㎛ (group_cer_sin for crowns of Ceramill Sintron) with the oxide layer and between 19 ㎛ and 28 ㎛ without the oxide layer. The internal gap varied between 33 ㎛ (group_ti_nem for test samples of Tizian NEM) and 75 ㎛ (group_gir_nb for the base material Girobond NB) with the oxide layer and between 30 ㎛ and 76 ㎛ without the oxide layer. The absolute marginal discrepancy and the internal gap were significantly influenced by the fabrication method used (P<.05). CONCLUSION. Different manufacturing techniques had a significant influence on the fitting accuracy of single crowns made from Co-Cr alloys. However, all tested crowns showed a clinically acceptable absolute marginal discrepancy and internal gap with and without oxide layer and could be recommended under clinical considerations. Especially, the new system Ceramill Sintron showed acceptable values of fitting accuracy so it can be suggested in routine clinical work.

A Study on the Economic Efficiency of Capital Market (자본시장(資本市場)의 경제적(經濟的) 효율성(效率性)에 관한 연구(硏究))

  • Nam, Soo-Hyun
    • The Korean Journal of Financial Management
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    • v.2 no.1
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    • pp.55-75
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    • 1986
  • This article is to analyse the economic efficiency of capital market, which plays a role of resource allocation in terms of financial claims such as stock and bond. It provides various contributions to the welfare theoretical aspects of modern capital market theory. The key feature that distinguishes the theory described here from traditional welfare theory is the presence of uncertainty. Securities has time dimensions and the state and outcome of the future are really uncertain. This problem resulting from this uncertainty can be solved by complete market, but it has a weak power to explain real stock market. Capital Market is faced with the uncertainity because it is a kind of incomplete market. Individuals and firms in capital market made their consumption-investment decision by their own criteria, i. e. the maximization of expected utility form intertemporal consumption and the maximization of the market value of firm. We noted that allocative decisions that had to be made in the economy could be naturally subdivided into two groups. One set of decisions concerned the allocation of first-period resources among consumption $C_i$, investment in risky firms $I_j$, and riskless investment M. The other decisions concern the distribution among individuals of income available in the second period $Y_i(\theta)$. Corresponing to this grouping, the theoretical analysis of efficiency has also been dichotomized. The optimality of the distribution of output in the second period is distributive efficiency" and the optimality of the allocation of first-period resources is 'the efficiency of investment'. We have found in the distributive efficiency that the conditions for attainability is the same as the conditions for market optimality. The necessary and sufficient conditions for attainability or market optimality is that (1) all utility functions are such that -$\frac{{U_i}^'(Y_i)}{{U_i}^"(Y_i)}={\mu}_i+{\lambda}Y_i$-linear risk tolerance function where the coefficients ${\mu}_i$ and $\lambda$ are independent of $Y_i$, and (2) there are homogeneous expectations, i. e. ${\Large f}_i(\theta)={\Large f}(\theta)$ for every i. On the other hand, the efficiency of investment has disagreement about optimal investment level. The investment level for market rule will not generally lead to Pareto-optimal allocation of investment. This suboptimality is caused by (1)the difference of Diamond's decomposable production function and mean-variance valuation model and (2) the selection of exelusive investment or competitive investment. In conclusion, this article has made an analysis of conditions and processes of Pareto-optimal allocation of resources in capital marker and tried to connect with significant issues in modern finance.

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The Effects of Assertiveness Traning and Value Clarification Training on Nurse's Conflict and Conflict Management Mode (주장훈련과 가치명료화훈련이 간호사의 갈등정도와 갈등관리 양식에 미치는 효과)

  • Park, Sang-Yeon
    • Journal of muscle and joint health
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    • v.2 no.1
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    • pp.41-72
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    • 1995
  • The purpose of this study is to examine the effects of assertiveness training and value clarification training on nurse's conflict and conflict management mode. Fifty seven registered nurses participated in the study ; they were employed by three general hospital located in Daegu, Korea. The study employs two treatment groups. The assertiveness training group consisted of subjects who participated in 90-120 minutes sessions of assertiveness training nine times over five weeks. The other treatment group, was adiministed nine, 90-120 minutes sessions of value clarification during the same period. For the control group, nursing subjects were appointed the training after five weeks. Pre-test evaluation were administered to all subjects in three groups prior to one week of the treatment. Role conflict Inventory-general(RCI-G) and Communication Conflict Inventory-general (CCI-G) measure nurse's conflict management mode. Post-test evaluation were administered to all subjects in three groups two weeks after the last session by Role Conflict Inventory-Specific(RCI-S), Communication Conflict Inventory-Specific (CCI-S), Management Model-Specific(CMMI-S). The analysis of variance(ANOVA) and covariance(ANCOVA) on gain scores were running the SPSS program. In order to test statistical differences among mean scores of the scales obtained after treatment, multiple comparisons were carried out by Turkey method. Conclusions obtained from the results are as follows. 1. The assertiveness training and the value clarification training were effective in decreasing the nurse's role conflict. The value clarification was more effective than the assertiveness training in decreasing the nurse's role conflict. 2. Both assertiveness training and value clarification training were effective in decreasing nurse's communication conflict. There was, however, no differences between assertiveness training and value clarification training in decreasing the nurse's communication conflict. 3. The assertiveness training and the value clarification training were quite effective in compromizing and collaborating conflict management mode, to reducing the withdrawl and accomodate, force and accomodate conflict management mode to conflict. There was no difference in the effectiveness of assertiveness training and value clarification. In assessing the effects of the treatments, this study employed different measurements. It is unclear whether the measurement affected the test results. It is worth conducting a further test using the same measurements. The results of future studies can be compared with those of this study. The homogeneity of the control group and treatment group is questionable. Futher studies may employ homogeneous sample group to evaluate whether the sample characteristics bias the test results. Assertiveness training or value clarification training for nurses can be utilized in nursing intervention.

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Influences of Self-esteem, Rehabilitation Motivation on Quality of Life in Stroke Pateints with Rehabilitation Therapy (재활치료 중인 뇌졸중 환자의 자아존중감, 재활동기가 삶의 질에 미치는 영향)

  • An, Eun-Seo;Suh, Soon-Rim;Kim, Eun-Hee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.176-187
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    • 2019
  • This study was conducted to investigate the levels of self-esteem, rehabilitation motivation and quality of life and to identify the influencing factors of quality of life in stroke patients who were receiving rehabilitation therapy. Data were collected from February 22 to March 20, 2016 using self-administered questionares and the data from 216 participants were analyzed using SPSS WIN 21.0 program(SPSS Inc., Chicago, IL, USA). The results of this study were as follows: the mean self-esteem was 3.09/5, rehabilitation motivation was 3.60/5, and quality of life was 2.95/5. Sex, age, education, caregiver, occupation, duration after attack, the degree of disability(dependence), and cognitive function were significantly associated with quality of life. There was positive correlation between quality of life and self-esteem(r=.45, p<.001) and there was positive correlation between quality of life and rehabilitation motivation(r=.27, p<.001). Variables such as self-esteem, duration after attack, the degree of disability(dependence), and cognitive function explained 43.6%(F=14.87 p=<.001) of the variance in quality of life in model 3. Consequently, it is needed to develop and apply nursing intervention and programs for improving self-esteem during rehabilitation in order to improve quality of life of stroke patients.