• Journal of Periodontal and Implant Science
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• v.37 no.2
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• pp.151-164
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• 2007

Objective: The sinus floor elevation procedures have been used to facilitate implant placement in the severely atrophic posterior maxilla. Many variables may have an influence on the outcomes of the sinus floor elevation in combination with implant treatment. The aim of this study was to analyze survival rate of implants placed in the edentulous maxillae of patients in whom sinus floor elevation was undertaken according to variables. Materials and Methods: It consisted of 96 patients(50 male and 46 female), ranging in age from 31 to 70 years(mean 49 years), who underwent sinus floor elevation procedure(94 implants in left side and 106 implants in right side) from 2001 to 2002. A total of 200 implants were placed in the grafted sinus(73 implants in lateral approach and 127 implants in crestal approach). All implants were restored by fixed prosthesis. All patients were healthy. Follow-up periods for implants were between 48 to 60 months. Results: The cumulative survival rate of implants was 91.5%. Gender, age and operation site did not have an influence on the survival rate. There was statistically significant differences for the implants which placed in less than 4 or 5 rom residual bone height, the survival rate was 60%, 81.4% respectively (p<0.05). There was no statistically significant difference of implants survival rate ac- cording to approach technique. The survival rate for 100% autogenous bone grafts was lower with respect to composite grafts containing autogenous bone and 100% substitutes. The survival rate for hydroxyapatite-coated implants was statistically significant lower than other textured group (p<0.05). Conclusion: Residual bone height, surface texture and graft materials have an influence on the survival rate. To use autogenous bone as a part of a composite bone replacement, implant texture which leads to more favorable implant-bone interface were necessary. To determine residual bone height for initial implant stability was important.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.1
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• pp.42-47
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• 2016

Adjacent housing units suffer inevitable thermal losses if an unheated unit exists in an apartment building. Thermal loss of the units adjoining the unheated apartment can be neglected because the contact area is small and insulators are located in the walls. When insulators are not included in the slab between the upper and lower units, 70% of the heat supplied by an Ondol system may be used in the original unit, but 30% is transferred to the unit on the lower floor. Another 30% can be obtained from the ceiling if the upper floor housing unit is heated. This strong thermal connection is a characteristic of Ondol heating in apartment buildings. When there is an unheated unit, the lower floor unit uses 42.3% more heating energy if there is no insulation and 19.5% if a 35 mm insulator is used as in the current guidelines. Therefore, much thicker insulation should be applied to weaken the thermal connection.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.2
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• pp.66-71
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• 2008

The data of the deformation and the stress according to time are studied at upper model of press and lower model of the blanking plate applied by press with the width, length and height of 0.4 m and 0.6 m respectively. The press is pushing downward on the plate fixed at the lower floor. These data are compared and investigated through this study. By using these results, there is the maximum deformation at 4 corners in the lower plate model of aluminium alloy fixed at lower floor. This deformation incase of elapsed time of 0.6 second becomes 4 times as much as in case of elapsed time of 0.2 second. The quantity of deformation at the lower plate model becomes more than at the upper press model to the extent of 10%. At the lower plate model of aluminium alloy, there is the maximum Von-Mises equivalent stress at 4 corners and both sides of middle area on the lower plate model of aluminium alloy. This stress in case of elapsed time of 0.6 second becomes 6 times as much as in case of elapsed time of 0.2 second. The Von-Mises equivalent stress of lower plate model becomes 2 times as much as that of upper press mode.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.3
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• pp.415-427
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• 1993

The purpose of this study was to evaluate the thermoregulatory responses to postures under different environmental conditions and to obtain the basal information for standard clothing weight, indoor climates, and working condition. Two adult female (22.5yrs, 46kg) were participated in this study. The experimental conditions were divided into three groups ; 1) comfort($27{\pm}1^{\circ}C$, $60{\pm}10%$), 2) hot($34{\pm}1^{\circ}C$, $60{\pm}10%$), and 3) cold($21{\pm}1^{\circ}C$, $50{\pm}10%$) condition. The postures performed were as follows; standing, sitting on the chair, sitting on the floor, and supine on the floor. At each condition, subjective sensations, 12 points skin temperature, rectal temperature, total and local sweat rate, pulse rates, blood pressure, skin blood flow rate were measured. The results were as follows : 1. Rectal temperature was high significant among groups in order of supine, sitting on the floor, sitting on the chair, standing posture(p<0.01). 2. Skin temperature was high in part of contact with the surface of the floor or wall and the effect of posture was greater in peripheral temperature than torso temperature. Sitting on the chair and sitting on the floor posture showed higher peripheral temperature than standing and supine posture. And peripheral temperature was lower in supine posture than any other postures. 3. Total and local sweat rate were decreased in order of standing, sitting on the chair, sitting on the floor, supine posture. 4. Pulse rate and disastolic blood pressure were higher in standing posture than supine posture, and there was significant difference between two postures(p<0.001). 5. Blood flow rate of thigh was high in sitting on the chair and sitting on the floor posture and low in standing posture. Blood flow rate of leg was low in standing posture significantly(p<0.01). 6. In comfort and hot condition, temperature sensation and comfort sensation were higher in standing posture and lower in supine posture than any other postures. In cold condition, temperature sensation was lower and comfort sensation was higher in standing and supine posture than any other postures. And supine posture was appeared positive in hot condition and negative in cold condition. From this study, we confirmed the effects of posture on human thermoregulatory responses. Results indicate that even under same conditions and clothing weight, the insulation of clothing will be different to postures.

• KIEAE Journal
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• v.12 no.4
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• pp.89-95
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• 2012

At present, many countries are trying to reduce green gas emissions to mitigate the effects of these gases on climate change. Year after year, there have been efforts to cut energy use for heating and cooling. Heating and cooling systems, common in all forms of housing, are increasing due to the constant supply of new housing resulting from improvements in economic growth and the quality of life. Thus, studies related to the design of cooling and heating systems to improve energy efficiency are expanding. Among the new designs, radiant floor cooling and heating systems which use capillary tubes are becoming viable means of reducing energy use. Radiant floor cooling and heating systems which use capillary tubes are creative and sustainable systems in which cool and hot water is circulated into capillary tube which has small diameter. In this study, the cooling and heating performance of this type of capillary tube system is investigated in an experimental study and a simulation using TRNSYS. The results of the experimental study show that under a peak load, a capillary tube radiant floor cooling system using geothermal energy can achieve desired indoor temperature without an additional heat source. The set room air temperature is maintained while the floor surface temperature, PMV and PPD remain within the comfort range. Also, this system is more economic than a packaged air conditioner system due to its higher COP. The results of the simulation show that the capillary tube radiant floor heating system maintains set temperature more stable than a PB pipe radiant floor heating system due to its lower supply temperature of hot water. In terms of energy consumption, the capillary tube radiant floor heating system is more efficient than the PB pipe radiant floor heating system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.518-521
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• 2018

As public transportation use increases, studies are being conducted to consider user convenience using IoT data collected via the bus information system. A low-floor bus means a bus that is designed to be 20 cm lower than a normal bus and can be wheelchair-accessible. However, the system in which the transportation weak is provided to use the low-floor bus is less than the system provided to the general user. In order to use the low-floor bus smoothly, as in the case of the general user, the service system for the weak driver is needed. In this paper, a low - floor bus reservation system is designed to provide a service for low - rise bus users to conveniently use low - floor buses.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.11 no.1
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• pp.7-14
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• 2015

This study has been purposed to provide thermal comfort range in accordance with the residential style of radiant floor heating space, and to compare it with the thermal comfort range at predicted mean vote. The survey for the thermal sensation vote to the subjects and the measurement of environmental factors has been executed, and regression analysis has been performed. It is interpreted that the combination of the physical factor and the psychological factor results lower neutral point of the floor sitting style than that of the chair sitting style. There are some difference between the measured predicted mean vote and the thermal sensation vote via survey, which appears to be caused by distinctive heat transfer characteristic of floor radiant heating space, such as, high radiant temperature and contact thermal sensation of floor surface.

• KIEAE Journal
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• v.8 no.1
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• pp.71-79
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• 2008

Lower birth rate and higher elder people are serious social problem in Korea. In 2003, the total birth rate is 1.19 per person, that record is lowest among OECD country. In 2005, Korea has been the aging society with 9.0% in aged population rate. Increasing of aged population results in elder estrangement and confliction with other generations. The social problem can be solved in some degree by improving housing environment and many kinds of welfare program. This study suggests a solution of the problem by applying community space located on ground level floor. The ground level floor of apartment has many physical benefits like connection to the earth, extension, safeness for the aged and child. in case of the National Rental apartment, small residential area and high rate of elder, child, the disabled make the ground level floor useful space for community. According to case study, almost the National Rental apartment hasn't enough facilities supporting various generations and don't supply comfortable environment. So, this study presents how to design the National Rental Apartment's community space located on ground level floor.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.105-112
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• 2007

Recently developed raised floor heating system is not only capable of basic function to reduce noise between floors, but also is a multi-functional floor heating system enabling natural ventilation. The procedure of this system for natural ventilation is to import outdoor air through bottom space of the floor heating system, circulate indoor space and discharge it out of ceiling. In winter, powerless natural ventilation is possible with buoyancy effect caused by temperature difference between outdoor and indoor. And it also allows saving of energy by importing pre-heated air in bottom space of the floor heating system. To evaluate ventilation performance of this system, on-site measurement was conducted in 2 test laboratories, and the nominal air change rate was satisfied as 0.4$\sim$0.8 h-1 under the condition of outdoor temperature $5^{\circ}C{\sim}-5^{\circ}C$, which was evaluated as highly possible to be applied as a natural ventilation system in multi-family houses.

• Journal of Korean Association for Spatial Structures
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• v.17 no.2
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• pp.33-41
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• 2017

Composite Floor system infilled with PCM(Phase Change Material) between upper and lower steel plates was developed to apply the steel frame. When steel frames were applied this system, it can absolutely reduce the duration of construction due to dry construction method. However to apply this system as a structural floor member without fire resistance covering, it must have 2 hours fire resistance performance. Because PCM consisted of three quarters of section with thermal insulation performance, fire resistance performance of this floor system was expected to easily have 2 hours fire resistance performance. This paper was to investigate behavior characteristics of PCM infilled floor system at elevated temperature using FEM analysis to develop the fire resistance performance of it.