• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2008.11a
• /
• pp.89-92
• /
• 2008

This research analyzed the basic characteristics of unhardened concrete and the compression strength characteristics of hardened concrete according to liquidity retention agent mix rate change to improve the liquidity fluidity retention performance of high performance concrete, and produced the following results. The moment fluidity retention agent is added according to fluidity retention agent mix rate change, which increased fluidity retention agent mix rate, slump flow decreased, and in the case of slump flow according to the progress time change by the fluidity retention agent mix rates, the more fluidity retention agent mix rate increased, the lower slump flow change rate became. The moment fluidity retention agent is added according to fluidity retention agent mix rate change, fluidity retention agent mix rate increased compared to non-mixture of fluidity retention agent, and the air amount by progress time change by the fluidity retention agent mix rates slightly increased, however target range is still met and unit volume mass is inversely proportional to air amount. Compression strength according to age progress by the fluidity retention agent mix rates was shown to increase slightly with increase in fluidity retention agent mix rate, and yet the difference was not significant.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.4
• /
• pp.708-717
• /
• 2009

Recently, Korea government decided to introduce RPS (Renewable Portfolio Standard) mechanism which requires electricity providers to gradually increase the amount of renewable energy sources such as wind, solar, bioenergy, and geothermal. As a consequence, it is expected that the long-term fuel mix would be changed to result in more expensive production and the increased production costs would be distributed to the rate payers via electricity tariffs. This paper presents the change in long-term fuel mix in year 2020 with the four RPS scenarios of 3%, 5%, 10% and 20%, and the methodologies for collecting the increased production costs through new tariff schedule. The studies on long-term fuel mix have been carried out with the GATE-PRO (Generation And Transmission Expansion Program) optimization package, a mixed-integer program developed by the Korea Energy Economics Institute and Hongik university. Three methodologies for distributing the production costs to the rate payers have also been demonstrated.

• Journal of Preventive Medicine and Public Health
• /
• v.23 no.3 s.31
• /
• pp.345-357
• /
• 1990

Accumulated data on medical care utilization among the insured in Korea Medical Insurance Corporation can explain the health status of the population. The purpose of this study was to analyze a change of the disease-mix and utilization pattern by controlling the size of the population enrollment. Major findings of the study are as follows : 1. The changes of inpatient disease-mix a. Utilization rate was 139.2% in 1988 against 1980. b. Disease groups higher than the average utilization rate included neoplasms, endocrine, nutritional and metabolic diseases and immunity disorders, mental disorders etc. Meanwhile, disease groups seen less often were infections and parasistic diseases, diseases of blood and bloodforming, diseases of the digestive system etc. c. Utilization rate was up 106.3% in 1988 compared to 1985, and diseases above that average level were ill-defined intestinal infections, chronic liver disease and cirrhosis, diabetes mellitus, essential hypertension, etc. d. The disease-mix by institution in 1988 compared to 1985 shows that chronic disorders rank high in general hospitals whereas opthalmologic, obstetric, and orthopedic diseases rank high in private clinics. 2. The changes of outpatient disease-mix a. Utilization rate was up 175.2% in 1988 compared to 1980. b. Disease groups higher than the average utilization rate included neoplasms, endocrine, nutritional and metabolic diseases and immunity disorders, mental disorders etc. And disease groups seen less often were infections and parasistic diseases, diseases of the respiratory system, diseases of the genitourinary system. etc. c. Utilization rate was up 104.0% in 1988 compared to 1985, and diseases above that average level were gastric ulcer, diseases of hard tissues of teeth, etc. And diseases seen below that average level were acute nasopharyngitis(common cold). acute upper respiratory infections of multiple or unspecified sites, etc. It was concluded that medical care utilization level was increased, and that, from 1980 to 1988, disease-mix shifted to the chronic disorders. Chronic disorders accounted for more medical care utilization in general hospitals.

• Journal of Ceramic Processing Research
• /
• v.19 no.6
• /
• pp.509-513
• /
• 2018

This study uses fly ash for non-shrinkage grout in order to develop strength of grout and improve its durability. We grind fly ash to the extent of $7,000cm^2/g$ and use ground fly ash and raw fly ash respectively at the proportion of 10%, 20%, 30% instead of OPC and compare the results drawn on the condition of each proportion. As a mixed material of grout, EVA and water-reducing agent is added in order to prevent bleeding and improve segregation resistance, CSA is added with a view to preventing drying shrinkage and improving early strength property. In regard to flow and flow time test for analyzing and evaluating workability, it is revealed that grouts of all mix proportions except raw fly ash 30% mix proportion satisfy all performance criteria. With regard to length change rate, grout with no admixture shows the highest shrinkage rate, but the rate is 0.0005%, extremely insignificant rate. As material age increases, compressive strength of two grouts, that is to say ground fly ash 10% and 20%-used grouts, exceed that of grout with no admixture or show high-level compressive strength.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.10
• /
• pp.28-37
• /
• 2011

Though Korea has introduced CBP(Cost Based pool) power trading system since 2001, long-term Generation system planning has been executed by government for Cost minimization every 2 years. Until currently the model which is used for Generation system planning and best-mix only considers cost minimization and total yearly or quarterly electricity demand every year. In a view point of one day power supply operation, technical characteristics, like the ramp up/down rate of total generation system, minimum up/down time and GFRQ(Governor Free Response Quantity), are very important. this paper analyzes Optimal Fuel-Mix for 2022 Korea generation system satisfying these constraints of each fuel type and considering pump storage plants, construction cost and $CO_2$ emission charge Using MILP(Mixed Integer Linear Programming) method. Also the sensitivity analysis which follows in future power industry environmental change accomplished.

• Journal of Preventive Medicine and Public Health
• /
• v.33 no.4
• /
• pp.393-401
• /
• 2000

Objectives : To evaluate the impacts of the DRG payment system on the behavior of medical insurance claimants. Specifically, we evaluated the case-mix index, the numbers of diagnosis and procedure codes utilized, and the corresponding rate of diagnosis codes before, during and after implementation of the DRG payment system. Methods : In order to evaluate the case-mix index, the number of diagnosis and procedure codes utilized, we used medical insurance claim data from all medical facilities that participated in the DRG-based Prospective Payment Demonstration Program. This medical insurance claim data consisted of both pre-demonstration program data (fee-for-service, from November, 1998 to January, 1999) and post-demonstration program data (DRG-based Prospective Payment, from February, 1999 to April, 1999). And in order to evaluate the corresponding rate of diagnosis codes utilized, we reviewed 820 medical records from 20 medical institutes that were selected by random sampling methods. Results : The case-mix index rate decreased after the DRG-based Prospective Payment Demonstration Program was introduced. The average numbers of different claim diagnosis codes used decreased (new DRGs from 2.22 to 1.24, and previous DRGs from 1.69 to 1.21), as did the average number of claim procedure codes used (new DRGs from 3.02 to 2.16, and previous DRGs from 2.97 to 2.43). With respect to the time of participation in the program, the change in number of claim procedure codes was significant, but the change in number of claim diagnosis codes was not. The corresponding rate of claim diagnosis codes increased (from 57.5% to 82.6%), as did the exclusion rate of claim diagnosis codes (from 16.5% to 25.1%). Conclusions : After the implementation of the DRG payment system, the corresponding rate of insurance claim codes and the corresponding exclusion rate of claim diagnosis codes both increased, because the inducement system for entering the codes for claim review was changed.

• Journal of Global Scholars of Marketing Science
• /
• v.16 no.1
• /
• pp.13-26
• /
• 2006

In this research, we develope a procedure for detecting a random non-stationarity to the individual's purchasing rate in a stationary NED model. On this purpose, we derive the likelihood ratio statistic for a testing null and alternative hypotheses defined as whether there is no significant structural change in a stationary NED model or any. Where the structural change comes from a random non-stationarity(marketing mix activities or seasonality, for example) to the individual's purchasing rate. We also apply the developed method to a panel data for a frequently purchased good. This research could be a solution to include the non-stationarity in a stationary NED model. We also expect that the developed model could give a signal for an early detection of significant changes in marketing environment, and a mean for a measurement of the effects of marketing mix activities.

• International Journal of Highway Engineering
• /
• v.20 no.1
• /
• pp.69-76
• /
• 2018

PURPOSES : This study determined the optimal usage rate of RAP (reclaimed asphalt pavement) using cold central-plant recycling (CCPR) on a road-surface layer. In addition, a mixture-aggregate gradation design and a curing method based on the proposed rate for the surface-layer mix design were proposed. METHODS : First, current research trends were investigated by analyzing the optimum moisture content, mix design, and quality standards for surface layers in Korea and abroad. To analyze the aggregate characteristics of the RAP, its aggregate-size characteristics were analyzed through the combustion asphalt content test and the aggregate sieve analysis test. Moreover, aggregate-segregation experiments were performed to examine the possibility of RAP aggregate segregation from field compaction and vehicle traffic. After confirming the RAP quality standards, coarse aggregate and fine aggregate, aggregate-gradation design and quality tests were conducted for mixtures with 40% and 50% RAP usage. The optimum moisture content of the surface-layer mixture containing RAP was tested, as was the evapotranspiration effect on the surface-layer mixture of the optimum moisture content. RESULTS : After analyzing the RAP recycled aggregate size and extraction aggregate size, 13-8mm aggregate was found to be mostly 8mm aggregate after combustion. After using surface-chipping and mixing methods to examine the possibility of RAP aggregate segregation, it was found that the mixing method contributed very little for 3.32%, and because the surface-chipping method applied compaction energy directly as the maximum assumption the separation ratio was 15.46%. However, the composite aggregate gradation did not change. Using a 40% RAP aggregate rate on the surface-layer mixture for cold central-plant recycling satisfied the Abroad quality standard. The optimum moisture content of the surface-layer mixture was found to be 7.9% using the modified Marshall compaction test. It was found that the mixture was over 90% cured after curing at $60^{\circ}C$ for two days. CONCLUSIONS : To use the cold central-plant recycling mixture on a road-surface layer, a mixture-aggregate gradation design was proposed as the RAP recycled aggregate size without considering aggregate segregation, and the RAP optimal usage rate was 40%. In addition, the modified Marshall compaction test was used to determine the optimum moisture content as a mix-design parameter, and the curing method was adapted using the method recommended by Asphalt Recycling & Reclaiming Association (ARRA).

• Environmental and Resource Economics Review
• /
• v.24 no.2
• /
• pp.411-433
• /
• 2015

This paper decomposed energy productivity changes across 14 Korean manufacturing industries into 5 components, technological catch-up(EC), technological progress(TC), and changes in labor-energy ratio(LC), capital-energy ratio(KC) and energy mix(EMC). Then we also figured out the possible relationship between energy productivity change and export growth rate across the industries. It is found that (1) technological progress, changes in capital-energy ratio and energy mix contribute to energy productivity growth in Korea during the sample period, (2) technological progress is the primary driving forces for energy productivity growth, (3) increase in export growth rate had a positive impact on energy productivity growth excepting a part of energy-intensive industries.

• Journal of Dairy Science and Biotechnology
• /
• v.14 no.1
• /
• pp.71-84
• /
• 1996

This study was conducted to examine the usability of sorbitol for the manufacture as low-calory ingredient and cryoprotectant against frost damage. When frozen yoghrt was made of replacing sucrose by sorbitol at yoghurt mix, the change of physicochemical and lactic acid bacteria, such as Str. thermophilus, L. bulgaricus, and mixed culture of Str. thermophilus, and L. bulgaricus(1:1), was studied during the frozen storage(-20$^{\circ}$C). During the incubation of yoghurt mix, the rapid growth of lactic acid bacteria in all sample was observed as the increase of sorbitol addition, but sample A and D were almost similar. This results suggested that sucrose could play role of effecting the growth stimulator, otherwise, sorbitol could inhibit the death of microorganism, following the genus. At the survival rate between lactic acid bacteria during freezing of -5$^{\circ}$C by ice cream freezer Str. thermophilus showed 26.19 to 34.76%, L. bulgaricus 3.97 to 5.20%, and mixed culture 17.16 to 40.87% respectively. L. bulgaricus showed the greater lethal rate than other genus. Sample C which mixed sucrose with sorbitol (1:2 ratio) was showed the lowest lethal rate. Therefore, it suggested that the use of this ration could be used for better anti-frost damage. During the storage of -20$^{\circ}$C, the number of lactic acid bacteria generally decreased in the stand point of genus and frozen storage period. The survival of lactic acid bacteria might be the addition of sorbitol which could have the effect of anti-forst damage. In all treatment, lactase activity showed the rapid decrease after freezing. During the period of frozen storage, it was shown the slow decreasing trend. In spite· of decreasing, the result during yoghurt mix incubation -5$^{\circ}$C freezing, and -20$^{\circ}$C frozen storage was different at the level. After 80 days of storage, the lactase activity was similar among all genus and sample. Despite differenting viscosity followed by genus, combination of mix, and pH, the ratio of 1 to 2(sucrose : sorbitol) showed the greatest viscosity. The water holding capacity of frozen yoghurt mix was closely related to viscosity. As increasing sorbitol amounts, hardness and cohesiveness were increased, but elastisity was decreased. The significant differences between sample was inoculated with Str. thermophilus. However, there were not significant difference from the sample inoculated with L. bulgaricus and mixed culture.