• International Journal of Air-Conditioning and Refrigeration
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• v.15 no.3
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• pp.101-107
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• 2007

Indoor air quality becomes of a concern recently in view of human health. This study investigates the air diffusion performance and the air change efficiency of a classroom, when outdoor air is introduced in two different ways in addition to the heating/cooling operation of a ceiling-mounted heat pump. A CFD analysis has been performed to investigate the effect of the discharge angle of the air jets from the heat pump for both parallel and series types of outdoor air system. It is observed that the series type creates more uniform indoor environment compared to the parallel type in general. It can be concluded the discharge angle should not be larger than 40o for the parallel type, in order not to generate thermal stratification in the room.

• Archives of design research
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• v.13 no.1
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• pp.87-100
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• 2000

This thesis concentrates on modern design with understanding the ooncept of design thinking. Functionalism and exactness in design result from the project that modern design attempted to change everyday life with mechanical design language. There is thought to be convenient and profitable, to link a function and a need, to make something with building-up process, and to give judgement something by dualism in the other side. That thoughts were produced by not only transition of production system from by hand to by machine but also atmosphere of society that enables one to know himself as a member of modern age.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.11
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• pp.1072-1078
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• 2005

The present study has been conducted to tune a PID controller for large thermal systems such as a thermal environment chamber. In spite of large thermal mass of the thermal chamber under test, its response delay time was found to be negligible mainly due to high air recirculation rate. In general, heating and cooling capacities tend to be small compared the size of a thermal environment chamber, which leads to long transient periods of one hour or so. In the study, a PI tuning method is suggested which makes system responses faster while reducing overshoots and hunting by utilizing efficiently proportional band of actuators.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.6
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• pp.487-496
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• 2012

Recently, utilization of building foundations as ground-coupled heat exchangers has attracted much attention because they reduce the cost and enhance the heat transfer. The objective of this study is to evaluate the performance of energy-slab ground-coupled heat exchanger installed in a commercial building. In order to demonstrate the energy transfer characteristics of the energy-slab, experiments were conducted from October 2010 to September 2011. The 1-year measurement results showed that the mean EWTs of brine returning from the energy-slab were $9.6^{\circ}C$ in heating season and $24.9^{\circ}C$ in cooling season, which were in a range of design target temperatures. In addition, the geothermal heat pump system with the energy-slab showed on-off operation according to the setting temperatures of secondary fluid in water storage tank. The results also showed that the energy-slab extracted heat of 198.6 kW from the ground and injected heat of 318.9 kW to the ground, respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.3
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• pp.292-300
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• 2014

The Laplace Transform solution is used as a mathematical model to analyse the thermal performance of the building constructed using different wall materials. The solution obtained from Laplace Transform is an analytical solution of an one dimensional, linear, partial differential equation for wall temperature profiles and room air temperatures. The main purpose of the study is showing the detail of obtaining solution process of the Laplace Transform. This study is conducted using weather data from two different locations in Korea: Seoul, Busan for both winter and summer conditions. A comparison is made for the cases of an on-off controller and a proportional controller. The weather data are processed to yield hourly average monthly values. Energy consumption load is well calculated from the solution. The result shows that there is an effect of mass on the thermal performance of heavily constructed house in mild weather conditions such as Busan. Building using proportional control experience a higher comfort level in a comparison of building using on-off control.

• Transactions of the KSME C: Technology and Education
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• v.4 no.1
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• pp.3-10
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• 2016

Heat pump unit performance is represented by the COP(Coefficient of Performance) and expressed by the one point design condition according to KS C 9306. However, when heat pump operated to the real buildings, the simulations are changed continuously according to the actual weather conditions, the building load and heat pump source conditions. The purpose of this paper is to evaluate the APF(Annual performance factor) for a climate dependent building integrated air-to-air heat pump system in major cities in Korea. TRNSYS simulation tool with an international MV standard based IPMVP 4.4.2 was utilized to perform the annual performance analysis. The APF with the multi-performance data based method was calculated as 2.29 for Daejeon residential building case while Busan residential building case appeared as the highest with 2.36.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.78-80
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• 2014

Silicone structural glazing (SSG) is a method utilizing a silicone adhesive to attach glass, metal, or other panel material to the structure of a building. Windload and other impact loads on the facade are transferred from the glass or panel through the silicone structural sealant to the systems' framework. Silicone structural glazing systems are currently a very common method of glazing throughout the world. Locally, structural silicone glazing has become very common to achieve aesthetically pleasing and high utilization of small land for both residential and commercial building. Although structural silicone glazing has been utilized for approximately thirty years in Korea, the understanding of its technology was low and limited. Consequently, Korean projects experienced many quality issues during assembly and construction, even in very recently finished buildings. Adhesion loss and water infiltration occurred on more than one project, and the time and cost to repair these issues were substantial. In general, there are two kinds of structural silicones depending on fabrication methods. 1part structural silicone is for site glazing system and 2part structural silicone is for unitized factory glazing system. In this paper, 2part structural silicone which is very common for factory fabricating curtainwall systems was evaluated with regards to various mixing ratio. Since the structural performance of 2part sealant can be affected by mixing ratios, some extra ranges of recommended mixing ratio were evaluated to see any performance differences. Besides on cure profile, comparative evaluations for mechanical properties and adhesion develop on common building substrates were conducted.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.4
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• pp.458-464
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• 2008

The structural health monitoring has been gaining more importance in civil engineering areas such as earthquake and wind engineering. The use of health monitoring system can also provide tools for the validation of structural analytical model. However, only few structures such as historical buildings and some important long bridges have been instrumented with structural monitoring system due to high cost of installation, long and complicated installation of system wires. In this paper, the structural monitoring system based on cheap and wireless monitoring system is investigated. The use of advanced technology of micro-electro-mechanical system(MEMS) and wireless communication can reduce system cost and simplify the installation. Further the application of wireless MEMS system can provide enhanced system functionality and due to low noise densities. Identification results are compared to ones using data measured from traditional accelerometers and results indicate that the system identification using wireless MEMS system estimates system parameters accurately.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.2
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• pp.183-189
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• 2010

A localization system for indoor robots is an important technology for robot navigation in a building. Our localization system imports the GPS system and consists of more than 3 satellite beacons and a receiver. Each beacon emits both an ultrasonic wave and radio frequency. The receiver in the robot computes the distance from it to the beacon by measuring the flying time difference between ultrasonic wave and radio frequency. It then computes its position with the distance information from more than 3 beacons whose positions are known. However, the distance information includes errors caused from the ultrasonic sensors; we found it to be limited to within one period of a wave (${\pm}2\;cm$ tolerance). This paper presents a method for predicting the maximum position error due to distance information errors by using Taylor expansion and singular value decomposition (SVD). The paper also proposes a measuring parameter such as sensitivity to represent the accuracy of the indoor robot localization system in determining the robot's position with regards to the distance error.

• Korean Journal of Computational Design and Engineering
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• v.18 no.4
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• pp.290-298
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• 2013

A walking navigation system (usually known as a locomotion interface) is an interactive platform which gives simulated walking sensation to users using sensed bipedal motion signals. This enables us to perform navigation tasks using only bipedal movement. Especially, it is useful for the certain VR task which emphasizes on physical human movement, or accompanies understanding of the size and complexity of building structures. In this work, we described system components of VR walking system and investigated several types of walking platform by literature survey. We adopted a MS Kinect depth sensor for the motion recognition and a treadmill which includes directional turning mechanism for the walking platform. Through the integration of these components with a VR navigation scenario, we developed a simple VR walking navigation system. Finally several technical issues were found during development process, and further research directions were suggested for the system improvement.