• The Journal of Korean Academy of Prosthodontics
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• 제50권4호
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• pp.243-248
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• 2012

Purpose: The purpose of this study is to compare the removal torque between prefabricated and customized implant abutment screw. Materials and methods: Three types of implant system (Osstem, Astra, Zimmer) were used. For each system, prefabricated abutment screw (control group) and customized abutment screw (test group) were used to connect the fixture and the abutment (n = 6). Digital torque gauze was used to control the tightening torque and the screws were tightened under each manufacturer's recommendation. 10 minutes after the connection the same tightening torque was applied, and 5 minutes after the second connection, the removal torque was measured. This procedure was repeated 10 times. In the cyclic loading test, 10 minutes after the first connection to the 6 groups (n = 3), the same tightening torque was applied, and a total of 1,000,000 time loading was applied at 30 degree angle to long axis with 50 N load. Repeated measures of ANOVA test (${\alpha}$=.05) was used as statistics to evaluate the effect of repeated loading number on the removal torque. Independent t-test was used to evaluate the difference in removal torque after cyclic loading. Results: The removal torque significantly decreased as the number of loading repetition increased (P<.05). In the 10 time repetition test, there was no significant difference between the prefabricated and customized implant abutment screw of the 3 implant system (P<.05). Also in the cyclic loading test, there was no significant difference between the prefabricated and customized implant abutment screw of the 3 implant system (P<.05). Conclusion: Within the limitation of this study, there was no significant difference in the removal torque between the prefabricated abutment screw and customized abutment screws.

• Journal of the Korea Institute of Building Construction
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• 제9권4호
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• pp.55-61
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• 2009

Recently, the number of high-rise buildings being built in Korea by major construction companies for residential and commercial use has been increasing. When constructing a high-rise building, it is necessary to apply massive amounts of concrete to form a mat foundation that can withstand the huge load of the upper structure. However, it is of increasing concern that due to limitations in terms of the amount of placing equipment, available job-sites and systems for mass concrete placement in the construction field, it is not always possible to place a great quantity of concrete simultaneously in a large-scale mat foundation, and for this reason consistency between placement lift cannot be secured. In addition, a mat foundation Is likely to crack due to the stress caused by differences inhydration heat generation time. To derive a solution for these problems, this study provides test results of a hydration heat crack reduction method by applying placement lift change and setting time control with a super retarding agent for mass concrete in a large-scale mat foundation. Mock-up specimens with different mixtures and placement liftswere prepared at the job-site of a newly-constructed high-rise building. The test results show that slump flow of concrete before and after adding the super retarding agent somewhat Increases as the target retarding time gets longer, while the air content shows no great difference. The setting time was observed to be retarded as the target retarding time gets longer. As the target retarding time gets longer, compressive strength appears to be decreased at an early stage, but as time goes by, compressive strength gets higher, and the compressive strength at 28 days becomes equal or higher to that of plain concrete without a super retarding agent. For the effect of placement lift change and super retarding agent on the reduction of hydration heat, the application of 2 and 4 placement lifts and a super retarding agent makes it possible to secure consistency and reduce temperature difference between placement lifts, while also extending the time to reach peak temperature. This implies that the possibility of thermal crack induced by hydration heat is reduced. The best results are shown in the case of applying 4 placement lifts.

• Journal of Bio-Environment Control
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• 제14권2호
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• pp.95-105
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• 2005

This study was carried out to file up using effect and requirement of energy for environmental design data of Pleurotus eryngii growing houses. Heating and cooling Degree-Hour (D-H) were calculated and compared for. some Pleurotus eryngii growing houses of sandwich-panel (permanent) o. arch-roofed(simple) type structures modified and suggested through field survey and analysis. Also thermal resistance (R-value) was calculated for the heat insulating and covering materials of the permanent and simple-type, which were made of polyurethane or polystyrene panel and $7\~8$ layers heat conservation cover wall. The variations of heating and cooling D-H simulated for Jinju area was nearly linearly proportional to the setting inside temperatures. The variations of cooling D-H was much more sensitive than those of heating D-H. Therefore, it was expected that the variations of required energy in accordance with setting temperature or actual temperature maintained inside of the cultivation house could be estimated and also the estimated results of heating and cooling D-H could be effectively used far the verification of environmental simulation as well as for the calculation of required energy amounts. When the cultivation floor areas are all equal, panel type houses to be constructed by various combinations of materials were found to by far more effective than simple type pipe house in the aspect of energy conservation maintenance except some additional cost invested initially. And also the energy effectiveness of multi-span house compared to single span together with the prediction of energy requirement depending on the level insulated for the wall and roof area could be estimated. Additionally, structural as well as environmental optimizations are expected to be possible by calculating periodical and/or seasonal energy requirements for those various combinations of insulation level and different climate conditions, etc.

• Journal of the Korean Wood Science and Technology
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• 제36권3호
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• pp.1-8
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• 2008

The lateral strength test of bending type was done to investigate the lateral capacity of the double bolt connection of domestic larix glulam according to bolt spacing. In the shear specimen, which is bolted connection in the inserted plate type, the hole of bolt was made, changing the diameter of bolt (12 mm and 16 mm), the number of bolt (single bolt : control and double bolt), the direction of bolt row (in parallel to grain : Type-A and in perpendicular to grain : Type-B) and the bolt spacing (Type-A : 4 d and 7 d and Type-B : 3 d and 5 d). Lateral capacity and failure mode of bolt connection were compared according to conditions. In prototype design (KBCS, 2000), the reduction factor of the allowable shear resistance that the bolt spacing is reduced was calculated. The results were as follows. 1) Bearing stress per bolt in the single and double bolt connection of Type-A was directly proportional to bolt diameter and bolt spacing. Bearing stress of Type-B decreased as bolt diameter was increased, and decreased by 2~10% when bolt diameter was increased. 2) In the single bolt connection and the double bolt connection of Type-A, the splitted failure was formed in the edge direction. When the bolt spacing was 3 d in Type-B, bolt was yielded more in the part of tension than in the part of compression, and the splitted failure started at the bolt in the part of tension. In the 5 d spacing specimen, the bolt in the part of tension was yielded similarly to bolt in the part of compression, and the splitted failure started in the part of compression. 3) In the prototype design, the reduction factor was calculated by non-dimensionizing the yielding load in the standard of bolt spacing (Type A : 7 d and Type B : 5 d). In 12 mm bolt connection, the reduction factor of bolt spacing 4 d (type-A) and single bolt connection was 0.87 and 0.55, respectively, and the reduction factor of bolt spacing 3 d (Type-B) and single bolt connection was 0.91 and 0.55, respectively. In 16 mm bolt connection, the reduction factor of bolt spacing 4 d (type-A) and single bolt connection was 0.96 and 0.76, respectively, and the reduction factor of bolt spacing 3 d (Type-B) and single bolt connection was 0.91 and 0.77, respectively.

• Journal of the Korean Institute of Landscape Architecture
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• 제46권6호
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• pp.60-74
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• 2018

This study was to investigate the pedestrian's thermal environments in the North Sidewalk of E-W Street during summer heatwave. We carried out detailed measurements with four human-biometeorological stations on Dongjin Street, Jinju, Korea ($N35^{\circ}10.73{\sim}10.75^{\prime}$, $E128^{\circ}55.90{\sim}58.00^{\prime}$, elevation: 50m). Two of the stations stood under one row street tree and hedge(One-Tree), two row street tree and hedge (Two-Tree), one of the stations stood under shelter and awning(Shelter), while the other in the sun (Sunlit). The measurement spots were instrumented with microclimate monitoring stations to continuously measure microclimate, radiation from the six cardinal directions at the height of 1.1m so as to calculate the Universal Thermal Climate Index (UTCI) from 24th July to 21th August 2018. The radiant temperature of sidewalk's elements were measured by the reflective sphere and thermal camera at 29th July 2018. The analysis results of 9 day's 1 minute term human-biometeorological data absorbed by a man in standing position from 10am to 4pm, and 1 day's radiant temperature of sidewalk elements from 1:16pm to 1:35pm, showed the following. The shading of street tree and shelter were mitigated heat stress by the lowered UTCI at mid and late summer's daytime, One-Tree and Two-Tree lowered respectively 0.4~0.5 level, 0.5~0.8 level of the heat stress, Shelter lowered respectively 0.3~1.0 level of the heat stress compared with those in the Sunlit. But the thermal environments in the One-Tree, Two-Tree and Shelter during the heat wave supposed to user "very strong heat stress" while those in the Sunlit supposed to user "very strong heat stres" and "exterme heat stress". The main heat load temperature compared with body temperature ($37^{\circ}C$) were respectively $7.4^{\circ}C{\sim}21.4^{\circ}C$ (pavement), $14.7^{\circ}C{\sim}15.8^{\circ}C$ (road), $12.7^{\circ}C$ (shelter canopy), $7.0^{\circ}C$ (street funiture), $3.5^{\circ}C{\sim}6.4^{\circ}C$ (building facade). The main heat load percentage were respectively 34.9%~81.0% (pavement), 9.6%~25.2% (road), 24.8% (shelter canopy), 14.1%~15.4% (building facade), 5.7% (street facility). Reducing the radiant temperature of the pavement, road, building surfaces by shading is the most effective means to achieve outdoor thermal comfort for pedestrians in sidewalk. Therefore, increasing the projected canopy area and LAI of street tree through the minimal training and pruning, building dense roadside hedge are essential for pedestrians thermal comfort. In addition, thermal liner, high reflective materials, greening etc. should be introduced for reducing the surface temperature of shelter and awning canopy. Also, retro-reflective materials of building facade should be introduced for the control of reflective sun radiation. More aggressively pavement watering should be introduced for reducing the surface temperature of sidewalk's pavement.

• Journal of Environmental Impact Assessment
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• 제24권1호
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• pp.16-34
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• 2015

Impervious covers(IC) are artificial structures, such as driveways, sidewalks, building's roofs, and parking lots, through which water cannot infiltrate into the soil. IC is an environmental concern because the pavement materials seal the soil surface, decreasing rainwater infiltration and natural groundwater recharge, and consequently disturb the hydrological cycle in a watershed. Increase of IC in a watershed can cause more frequent flooding, higher flood peaks, groundwater drawdown, dry river, and decline of water quality and ecosystem health. There has been an increased public interest in the institutional adoption of LID(Low Impact Development) and GI(Green Infrastructure) techniques to address the adverse impact of IC. The objectives of this study were to construct the modeling site for a samll urban watershed with the Storm Water Management Model(SWMM), and to evaluate the effect of various LID techniques on the control of rainfall runoff processes and non-point pollutant load. The model was calibrated and validated using the field data collected during two flood events on July 17 and August 11, 2009, respectively, and applied to a complex area, where is consist of apartments, school, roads, park, etc. The LID techniques applied to the impervious area were decentralized rainwater management measures such as pervious cover and green roof. The results showed that the increase of perviousness land cover through LID applications decreases the runoff volume and pollutants loading during flood events. In particular, applications of pervious pavement for parking lots and sidewalk, green roof, and their combinations reduced the total volume of runoff by 15~61 % and non-point pollutant loads by TSS 22~72 %, BOD 23~71 %, COD 22~71 %, TN 15~79 %, TP 9~64 % in the study site.

• Journal of the Korea Organic Resources Recycling Association
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• 제17권3호
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• pp.71-81
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• 2009

Food waste has been actively used as a composting material in order to reduce the environmental pollution load and to enhance the recycling of resources. In this study, the longterm effects of continuous application of food waste compost to soils on both the crop production and the soil properties were examined to ensure the safety of food waste compost in agricultural use. In addition, we collected the preliminary data for establishing standard application rate of food waste compost for agricultural utilization. Based on conventional nitrogen application rate of chemical fertilizer for crop cultivation, pig manure compost $(24g\;N\;kg^{-1}$, $8g\;P_2O_5\;kg^{-1}$, and $10.4g\;K_2O\;kg^{-1})$ and food waste compost ($20g\;N\;kg^{-1}$, $20.1g\;P_2O_5\;kg^{-1}$, and $6.5g\;K_2O\;kg^{-1}$) were applied to the upland soil in $2{\times}2{\times}2m$ lysimeter in which lettuce (Lactuca sativa var. crispa), Chinese cabbage (Brassica campestris subsp. napus var. pekinensis), red pepper (Capsicum annuum), and potato (Solanum tuberosum) were grown continuously. The crops grown in soils to which food waste compost applied showed better growth responses than the control, whereas some variations were observed in the crops grown in chemical fertilizer treated soils. Continuous application of food waste compost increased the contents of organic matter, nitrogen, and phosphorus, which resulted in improving soil aeration.

• The Korean Journal of Physiology and Pharmacology
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• 제20권3호
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• pp.287-295
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• 2016

Involuntary physical activity induced by the avoidance of electrical shock leads to improved endurance exercise capacity in animals. However, it remains unknown whether voluntary stand-up physical activity (SPA) without forced simulating factors improves endurance exercise capacity in animals. We examined the effects of SPA on body weight, cardiac function, and endurance exercise capacity for 12 weeks. Twelve male Sprague-Dawley rats (aged 8 weeks, n=6 per group) were randomly assigned to a control group (CON) or a voluntary SPA group. The rats were induced to perform voluntary SPA (lifting a load equal to their body weight), while the food height (18.0 cm) in cages was increased progressively by 3.5 every 4 weeks until it reached 28.5 cm for 12 weeks. The SPA group showed a lower body weight compared to the CON group, but voluntary SPA did not affect the skeletal muscle and heart weights, food intake, and echocardiography results. Although the SPA group showed higher grip strength, running time, and distance compared to the CON group, the level of irisin, corticosterone, genetic expression of mitochondrial biogenesis, and nuclei numbers were not affected. These findings show that voluntary SPA without any forced stimuli in rats can effectively reduce body weight and enhance endurance exercise capacity, suggesting that it may be an important alternative strategy to enhance endurance exercise capacity.

• Journal of Intelligence and Information Systems
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• 제18권4호
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• pp.43-57
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• 2012

To enhance the competitive advantage in a constantly changing business environment, an enterprise management must make the right decision in many business activities based on both internal and external information. Thus, providing accurate information plays a prominent role in management's decision making. Intuitively, historical data can provide a feasible estimate through the forecasting models. Therefore, if the service department can estimate the service quantity for the next period, the service department can then effectively control the inventory of service related resources such as human, parts, and other facilities. In addition, the production department can make load map for improving its product quality. Therefore, obtaining an accurate service forecast most likely appears to be critical to manufacturing companies. Numerous investigations addressing this problem have generally employed statistical methods, such as regression or autoregressive and moving average simulation. However, these methods are only efficient for data with are seasonal or cyclical. If the data are influenced by the special characteristics of product, they are not feasible. In our research, we propose a forecasting framework that predicts service demand of manufacturing organization by combining Case-based reasoning (CBR) and leveraging an unsupervised artificial neural network based clustering analysis (i.e., Self-Organizing Maps; SOM). We believe that this is one of the first attempts at applying unsupervised artificial neural network-based machine-learning techniques in the service forecasting domain. Our proposed approach has several appealing features : (1) We applied CBR and SOM in a new forecasting domain such as service demand forecasting. (2) We proposed our combined approach between CBR and SOM in order to overcome limitations of traditional statistical forecasting methods and We have developed a service forecasting tool based on the proposed approach using an unsupervised artificial neural network and Case-based reasoning. In this research, we conducted an empirical study on a real digital TV manufacturer (i.e., Company A). In addition, we have empirically evaluated the proposed approach and tool using real sales and service related data from digital TV manufacturer. In our empirical experiments, we intend to explore the performance of our proposed service forecasting framework when compared to the performances predicted by other two service forecasting methods; one is traditional CBR based forecasting model and the other is the existing service forecasting model used by Company A. We ran each service forecasting 144 times; each time, input data were randomly sampled for each service forecasting framework. To evaluate accuracy of forecasting results, we used Mean Absolute Percentage Error (MAPE) as primary performance measure in our experiments. We conducted one-way ANOVA test with the 144 measurements of MAPE for three different service forecasting approaches. For example, the F-ratio of MAPE for three different service forecasting approaches is 67.25 and the p-value is 0.000. This means that the difference between the MAPE of the three different service forecasting approaches is significant at the level of 0.000. Since there is a significant difference among the different service forecasting approaches, we conducted Tukey's HSD post hoc test to determine exactly which means of MAPE are significantly different from which other ones. In terms of MAPE, Tukey's HSD post hoc test grouped the three different service forecasting approaches into three different subsets in the following order: our proposed approach > traditional CBR-based service forecasting approach > the existing forecasting approach used by Company A. Consequently, our empirical experiments show that our proposed approach outperformed the traditional CBR based forecasting model and the existing service forecasting model used by Company A. The rest of this paper is organized as follows. Section 2 provides some research background information such as summary of CBR and SOM. Section 3 presents a hybrid service forecasting framework based on Case-based Reasoning and Self-Organizing Maps, while the empirical evaluation results are summarized in Section 4. Conclusion and future research directions are finally discussed in Section 5.

• Journal of agricultural medicine and community health
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• 제12권1호
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• pp.36-53
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• 1987

It is utmostly important to establish the efficient fitable way of peoples' active participation in primary health care especially in the areas where the public or governmental service input for the basic health care is insufficient like as in rural areas of Korea. In light of above reason, this study focused mainly on the evaluation of roles and activities of village health workers (VHWs) who were selected from grass- root level of village people in order to derive further motivation for active participation. This is believed to be a sort of feedback mechanisms. Actually, the authors collected the activity reports of VHWs who had been devoting themselves in the primary health care services of Jeomdong Area, of Yeoju Gun one of Korea University Community Health Action Programmes and survey record on the VHWs activity from correspondent people. 1 hose data were analyzed through computer programmed package. The activities performed by VHWs were limited to the performance in 1985 for conveniance. The summarized results were as follows; 1) General characteristics of VHWs. Among a total of 28 VHWs in the area, about 39.3g of them have been replaced up to the date since the implementation in 1983, because of moving out, occupational employment and of others. The age of majority (75.0%) lied between the range of 30-50, and educational background of 67.9% belonged to category of primary school graduation, about 50% of them experienced to be or were also entiled "chief of women club" of corresponding villages. 2) Work-load of VHWs. Each VHW was assigned for tasks of health care for average 55 households of 248 persons. They shared approximately 6 days a month for the activity in average and it covered 17 cases of basic health care in a month. A half of the VHWs performed home visits irregularly without solidified schedule. 3) Work performance analysis. Informations collected through VHWs were compared with data from official vital registration at local administration center "Myon Office" in 1985. VHWs collected 100.8 of new born, 116.2 of death, 58.3 of move in and 74.8 of move out in comparison with 100.0 of official registration each. Pregnant women of 79.8% of mothers among the total pregnancy of 94 which were confirmed as normally delivered or aborted cases by all means afterwards had been detected by VHWs as being pregnant and all of them received some of antenatal cares by VHWs. All(100%) of delivered women were detected by VHWs through home visits and they were cared postnatally. Whereas, according to the records of birth registration, the places of delivery were clinic in 33.7%, and mother's home in 66.3%, VHWs reported them to be clinic in 48.9%, midwifery in 20.2%. It was cleared that most of misinformation was caused by uncautious filling of birth registration at notification. Among the total of 717 eligible women under age 44 years, family planning status of 92.6% was reported by VHWs confirming practice of control to be 70.8% of reported fertile women. 4) Attitude of VHW on the roles and functions. Although 92.0% of VHWs expressed VHWs to be worthwhile, only 52.0% of them had dignity and satisfaction in their activity and 44.0% of them had passive attitude of working saying they followed direction regardlessly. Concerning difficulties in performance as a VHW, 60.7% of them pointed out lacking of medical and health related knowledge by themselves. Still, 64.0% of them thought visiting unfamilier house to be awful and 40.0% complained forms of activity to be difficult and hard. It was also revealed that 56.6% confessed lack of interest on community health service itself. Most of VHWs needed more educational training especially on clinical fields such as cares of gynecological diseases, hypertension, diabetes, and other chronic diseaes of the aged. Regular on-the-job basic trainings were said to be needed twice a year.