• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.9 no.2
• /
• pp.15-21
• /
• 2014

The long memory properties of the hedge ratio for stock and futures have not been systematically investigated by the extant literature. To investigate hedge ratio' long memory, this paper employs a data set including KOSPI200 and S&P500. Coakley, Dollery, and Kellard(2008) employ a data set including a stock index and commodities foreign exchange, and suggested the S&P500 to be a fractionally integrated process. This paper firstly estimates hedge ratios with two dynamic models, BEKK(Bollerslev, Engle, Kroner, and Kraft) and diagonal-BEKK, and tests the long memory of hedge ratios with Geweke and Porter-Hudak(1983)(henceforth GPH) and Lo's modified rescaled adjusted range test by Lo(1991). In empirical results, two hedge ratios based on KOSPI200 and S&P500 show considerably significant long memory behaviours. Thus, such results show the hedge ratios to be stationary and strongly reject the random walk hypothesis on hedge ratios, which violates the efficient market hypothesis.

• Asian-Australasian Journal of Animal Sciences
• /
• v.21 no.2
• /
• pp.232-236
• /
• 2008

This experiment was performed to investigate the effects of two energy levels and four lysine:digestible energy (DE) ratios on the apparent digestibility of nutrients in finishing pigs. The experiment was conducted using a $2{\times}4$ randomized complete block (RCB) design with three replicates. Twenty-four cross-bred finishing barrows ((Landrace${\times}$Yorkshire)${\times}$Duroc) with an average body weight of $64.2{\pm}0.69kg$ were assigned to one of eight treatments. Each barrow was placed in an individual metabolism crate and dietary treatment and water was provided ad libitum. Diets were designed to contain lysine:ME ratios of 1.5, 1.8, 2.1 and 2.4 g/Mcal at 3.35 and 3.6 Mcal/kg of diet in a $4{\times}2$ factorial arrangement. Dry matter (DM), ash, Ca and P digestibility were not affected by energy density or lysine:DE ratios. Crude fat digestibility increased as the energy density increased from 3.35 to 3.6 Mcal of DE/kg. Increasing the lysine:DE ratio also increased crude protein digestibility. There were no interactions between energy density and lysine:DE ratio in terms of nutrient digestibility. Nitrogen excretion via feces was not affected by energy density and lysine:DE ratio, while nitrogen excretion via urine was significantly affected by energy density and lysine:DE ratio. The apparent digestibility of all amino acids except for isoluecine, arginine and aspartic acid as well as average values of essential amino (EAA), non-essential amino acids (NEAA) and total amino acid digestibility (p>0.05) were not affected by energy density. The apparent digestibility of all amino acids except for leucine, proline, alanine and tyrosine, NEAA and total amino acid digestibility were significantly affected by lysine: DE ratio (p<0.05). Interactive effects of energy and lysine:DE ratio also significantly affected amino acid digestibility except for isoleucine, alanine, cystine, leucine, phenylalanine, glutamine and proline (p<0.05). In conclusion, these results suggest that maintaining the appropriate lysine:DE ratio becomes more important as the energy density of the diet increases. Consequently, increasing the lysine:DE ratio can result in increased crude protein digestibility and urinary nitrogen excretion, although apparent protein digestibility and nitrogen excretion were not affected by energy density Furthermore, increasing the lysine:DE ratio also increased the apparent digestibility of essential amino acids, except for leucine, regardless of energy density. The optimum lysine:DE ratio for maximum essential amino acid digestibility of the $64.2{\pm}0.69kg$ pig is approximately 2.4 g of lysine/Mcal of DE.

• Korean Journal of Community Nutrition
• /
• v.9 no.3
• /
• pp.263-273
• /
• 2004

The purpose of this study was to investigate the pattern of individual fatty acid intake and to compare serum lipid levels and total serum fatty acid composition of high school students in Seoul (total : 234 ; male : 91 ; female : 143) In serum lipid levels, total cholesterol (Chol.), HDL-Chol. and LDL-Chol. levels of female students were significantly higher than those of male students and there was no significant difference between High Fish ＆ Low Meat intake (HFLM) and Low Fish ＆ High Meat intake (LFHM) groups. The average fat intake was 22-25 energy % of total subjects and especially, that of LFHM group was 29%, which were over the recommendation level. Although the average P/M/S ratio of dietary fat was 1.1/1.2/1.0, the average range of $\omega6/\omega3$ fatty acid ratio of dietary fat was found to be 17.9-20.7, which was far beyond the suggested range, 4-10. The average intake of cholesterol of total subjects was 360mg. LFHM group had more meats and beverages such as carbonated drinks and tended to have less beans, vegetables and mushrooms. In addition, LFHM group had more energy and fat intake than those of HFLM group, the P/S ratio of dietary fat (0.73) was lower than the recommended ratio. Serum C16 : 0 composition of LFHM group was significantly higher than that of HFLM group, and EPA and DHA composition of HFLM was significantly lower than that of LFHM. Therefore, in HFLM group, the P/S ratio of serum fatty acids was significantly higher and the $\omega6/\omega3$ ratio was lower. Dietary C18 : 0 was negatively correlated with serum EPA and DHA composition. Individual PUFA intake was negatively correlated with serum C16 : 0 and sum of SFA, and positively correlated with serum C18 : $2\omega6(LA)\;,\;sum\;o;\omega6$ and sum of PUFA. Serum C18 : 1, C18 : $3\omega3\; and\; C20\;:\;4\omega6$ (AA) compositions were not correlated with dietary fatty acid. Only serum triglyceride (TG) levels were significantly correlated with serum fatty acid compositions. Sum of SFA, C14 : 0, C16 : 0, sum of MUFA and C18 : 1 compositions were positively correlated with serum TG levels, but LA, AA, sum of PUFA and P/S ratio were negatively correlated with it.

• Journal of the Korean Society of School Health
• /
• v.8 no.1
• /
• pp.143-154
• /
• 1995

Korea has been recently reducing the quality of life as well as rising medical cost because of the increase of chronic diseases. But we can prevent those chronic diseases through the improvement of environment or life style. We evaluated the educational effectiveness of chronic diseases(hypertention, diabetes, cancer, stroke and other chronic diseases) designed to increase the knowledge, attitude and practice of chronic diseases among university students. Between August 1994 and November 1994, we implemented chronic diseases prevention instruction in intervention students; unmatched control students were selected in same university. We conducted pre- and post-intervention surveys both intervention and control students with self-reported questionnaires(50 items). We assigned score(0-4 points) to items and conducted a analysis of covariance(ANCOVA) with sex, grade and economic status as the covariate, using the SAS PC computer statistical package. And we culculated odds ratio with safety scores between intervention and control students. The results of this study were followed. 1. In demographic characteristics of subjects both pre- and post intervention, we found no significant differences in intervention and control students at religion, father's education, mother's education, mother's occupation and type of residence(p>0.05), but we found significant differences at sex(p<0.001), grade(p<0.001) and economic status(p<0.05). 2. The sex, grade and economic status-adjusted mean prevention knowledge scores for diabetes and stroke increased from the pre- to post-survey in the intervention students(p<0.001), but control students did not increased(p>0.05). As odds ratios in knowledge were below 1, the knowledge of intervention students were higher than control students. 3. The attitudes for general adult health increased from the pre- to post-survey in the intervention students(p<0.05), but control students did not increased(p>0.05). As odds ratios in attitudes were approximately 1, we can not say effectiveness in intervention students 4. The pratices for cancer and stroke increased from the pre- to post-survey in both the intervention and control students(p<0.001). Also odds ratio of hypertention was 0.91, and that of stroke was 1.14. 5. Health related behaviors did not increased from the pre- to post- survey in both the intervention and control students(p>0.05). But odds ratio of drinking was 0.76 and that of body weight was 1.21. 6. Health status did not increased from the pre- to post- survey in both the intervention and control students(p>0.05). As odds ratio of health status was 1.09, prevention education was not effect in intervention students We would like to recommend as follows; 1. University students must learn about prevention of chronic diseases. Because the knowledge of invetervention students was higher than that of control students. 2. The prevention education of chronic diseases should be taught from primary school. 3. Adult health education for university students must be practiced continuously. Education period(l5 weeks) in this study was not complete. 4. The evaluation of chronic diseases was conducted real measurement(such as BP check) as well as self reported-survey. 5. Educational materials(video tape, pamphlet) related the prevention of chronic diseases should be developed at national level. And we must easely use those materials. 6. The prevention education of chronic diseases should be made through mass media as well as school education.

• Geomechanics and Engineering
• /
• v.24 no.1
• /
• pp.57-65
• /
• 2021

The effects of initial soil fabric and aspect ratio (AR) on the small-strain stiffness (G0) of granular soils are studied by employing discrete element method (DEM) numerical analysis. Elongated clumps composed of subspheres were adopted, and the G0 values were obtained by DEM simulations of drained triaxial tests under different densities and initial confining pressure (p0). The DEM simulations indicate that the initial soil fabric has an insignificant effect on G0. The effect of the AR on G0 is related to the initial density. Namely, for dense specimens, G0 first increases with increasing AR, reaching a plateau value when the AR ≥ 1.5. However, for loose specimens, G0 gradually increases as the AR increases. Microscopic examination reveals that G0 uniquely depends on the coordination number of the particles (CN-particle) rather than the subspheres (CN-sphere) at the particulate level for the effects of initial soil fabric and AR. Finally, Poisson's ratio ν0 is also determined by CN-particle. In addition, based on data in literature and this study, ν0 can be fitted as ν0 = 5.920(G0/(p0)1/3)-0.99, which can be used to predict ν0 of granular soils based on the measured G0.

• Journal of Nutrition and Health
• /
• v.32 no.7
• /
• pp.802-811
• /
• 1999

The purposes of this study were to 1) examine the dietary patterns of fatty acids and the fatty acid composition in serum, 2) determine selenium (Se) concentrations, and 3) investigate how serum fatty acid compositon affects serum levels of Se in Korean elementary school children. The subjects consisted of 168 school children(82 boys & 86 girls) belonging to 1st through 6th grades, and their dietary assessment was evaluated. The serum fatty acid composition was analyzed by GLC, and the ICP/MS method was employed to measure serum Se concentration. Total average intake of PUFA, MUFA and SFA were 10.5g, 12.7g, 11.2g respectively. Total average dietary P/M/S ratio was 1.10/1.18/1.0. The average intake of $\omega$3 fatty acids and $\omega$6 fatty acids were 1.33g, 9.19g, respectively. The $\omega$6/$\omega$3ratio was 14.2 which is higher than the recommended range. In serum fatty acid composition, PUFA, MUFA, SFA were 40.6%, 28.1% and 31.6% respectively. The average $\omega$3 fatty acid composition was 3.80%, and the mean value of $\omega$6 series was 36.8%. The M/S ratio of girls was significantly higher than boy's in fatty acids intake and in serum composition. Mean Se concentration of total subjects was 416.7ug/l and it was significantly higher in the lower grades(1st-3rd)than in the upper grades(4th~6th, p<0.05). Although the mean serum Se concentration was negatively correlated with PUFA composition in total boys and girls, it was not significant. Serum Se concentration was negatively correlated with P/S ratio and C24:1 concentration(p<0.05). In addition, serum composition of $\omega$6 PUFA and C24:1 showed negative correlations with serum Se in only lower grades girl(1st~3rd), and further studies are needed to clarify in these phenomena. In conclusion, the mean serum Se concentration was significantly lower in upper grades (4th~6th)than in lower grades(1st~3rd) of elementary school children and was negatively correlated with P/S ratio of serum fatty acids. More detailed studies on relationship between Se and fatty acids are required.

• Journal of Korean Society of Water and Wastewater
• /
• v.21 no.5
• /
• pp.551-558
• /
• 2007

From the view point of biological wastewater treatment, C/N ratio is one of the most important factor in biological nutrient removal process. However, municipal sewage in Korea is characterized by extremely low content of carbon source and relatively higher portion of N source. Accordingly, it is necessary to dose external carbon source in order to obtain higher degree of carbon source within the process. In this study, the effects of pH pretreatment as an alternative plan for increasing carbon source on the cell disruption and COD solubility of waste activated sludge were conducted under well defined experimental conditions. During 5 hours, the value of COD solubilization rate ($S_R$) at pH 11.5 is approximately 4.4 times higher than the value of $S_R$ at pH 9.5. It is expected that the level of SCOD increased due to the result from cell disruption. However, VSS/TSS ratio was not significantly changed after 5 hours. As Alkalinity changes gradually from less than 15, 30 and 60 meq NaOH/L, average RBCOD/SCOD fraction showed 34, 36 and 45%,respectively.

• Journal of Biomedical Engineering Research
• /
• v.15 no.2
• /
• pp.189-194
• /
• 1994

Effects of ${AI_2O_3}/{P_2O_5}$ ratio on the crystallization of a series of glasses with the nominal composition of 41.4wt % $SiO_2$, 35.0wt % CaO, 20.6wt % (${P_2O_5}$+${AI_2O_3}$) and 3.0wt% MgO were investigated with DTA, XRD and SEM. The major crystalline phases are apatite and anorthite. The glass transition temperature ($T_g$) and the softening point ($T_s$) are shifted to the upper temperature by increasing $AI_2O_3$ content. The temperature of apatite crystallization ($T_{p1}$) is increased by $AI_2O_3$ content, but the tempera¬ture of anorthite crystallization ($T_{p2}$) is not affected significantly. With increased of $AI_2O_3$, the apatite crystallization is decreased, but anorthite crystallization is increased.

• Korean Journal of Human Ecology
• /
• v.4 no.1
• /
• pp.36-45
• /
• 2001

This study was performed to determine the changes of maternal iron status during pregnancy cross sectionally, and to evaluate the appropriateness of the cut-off points of hemoglobin (Hb). hematocrit (Hct), serum transferrin receptor (sTfR) and sTfR : ferritin ratio for assessing iron deficiency status based on serum ferritin level (< 12${\mu}g$/L). Serum Hb concentrations in the first trimester were significantly higher (p < 0.05) than those in the second and third trimester. Serum levels of iron and ferritin in the third trimester were significantly lower (p < 0.05) than those in the first and second trimester. On the other hand, sTfR:ferritin ratios in the third trimester were significantly higher (p < 0.05) than those in the first and second trimester. sTfR concentrations did not change significantly during pregnancy. The appropriate cut-off points of Hb were 11.5g/dL for whole period of pregnancy. 12.0g/dL for 1st trimester. and 11.5g/dL for both 2nd and 3rd trimester. The good cut-off points of Hct were 34% for whole period of pregnancy. 36% for 1st trimester. and 34% for both 2nd and 3rd trimester The suitable cut-off points of TIBC were 400${\mu}g$/dL for whole period of pregnancy. 360${\mu}g$/dL for 1st trimester, and 400${\mu}g$/dL for both 2nd and 3rd trimester. Any cut-off point of sTfR could not be selected because of its low sensitivity and specificity. The proper cut-off point of sTfR : ferritin ratio was 600 or 650 for all the periods determined except the first trimester. In conclusion, there were no reliable cut-off levels of sTfR and those of sTfR : ferritin ratio showed low specificity. The cut-off values of Hb and Hct for assessing iron deficiency were slightly higher than the values used to evaluate anemia. Thus, if appropriate cut-off levels were applied, Hb. Hct, or TIBC might be useful indices for evaluating iron deficiency as well as anemia.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.237-238
• /
• 2008

Electrical properties of Pd/Zn/Pd/Au contacts to p-InP were investigated as function of the V/III ratio of p-InP. P-type InP was made by the Zn diffusion into InP and activation process with rapid thermal annealing (RTA) measurement. After activation, the hole concentration was two orders of magnitude higher than that of the sample having only diffusion process. According to transmission line method (TLM) results, the specific contact resistance of p-InP was lower as used InP having the lower V/III ratio. The experimental results represent that the diffusion of Zn in undoped InP deeply related to the equilibrium between interstitials and substitutional Zn is established via indium interstitials.