• Journal of Energy Engineering
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• v.21 no.3
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• pp.211-220
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• 2012

In study to investigate losing energy of building in window, we analyze the heating loss parts in the material of structure throughout modeling of window system. Also, by making modeling in the building using simulation, we investigate the heating load variation of building in window. According to the type of windows and the material of structure, we analyze the energy variation of building and a temperature variation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.4
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• pp.351-357
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• 2012

To reduce the summertime cooling load of a plant factory, a concept design was performed for the double skin window which utilizes the low temperature air from a ground coupled heat exchanger. The design parameters were selected as the number of cavity air inlet, the cavity thickness, the location of cavity air inlet, and the configuration of cavity air outlet. A parametric study was conducted in a systematic way to evaluate the heat transfer characteristics of the double skin window. As the number of cavity air inlet and the cavity thickness increase, the heat flux from outside air to indoor air was decreased. The effect of the location of cavity air inlet was not significant and the larger cavity air outlet area gave us relatively better heat blocking performance from outside hot air. This study demonstrated that it is possible to develop an improved double skin window by utilizing a ground coupled heat exchanger.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.2
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• pp.48-55
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• 2020

Recently, a study of prognosis and health management (PHM) was conducted to diagnose failure and predict the life of air craft engine parts using sensor data. PHM is a framework that provides individualized solutions for managing system health. This study predicted the remaining useful life (RUL) of aeroengine using degradation data collected by sensors provided by the IEEE 2008 PHM Conference Challenge. There are 218 engine sensor data that has initial wear and production deviations. It was difficult to determine the characteristics of the engine parts since the system and domain-specific information was not provided. Each engine has a different cycle, making it difficult to use time series models. Therefore, this analysis was performed using machine learning algorithms rather than statistical time series models. The machine learning algorithms used were a random forest, gradient boost tree analysis and XG boost. A sliding window was applied to develop RUL predictions. We compared model performance before and after applying the sliding window, and proposed a data preprocessing method to develop RUL predictions. The model was evaluated by R-square scores and root mean squares error (RMSE). It was shown that the XG boost model of the random split method using the sliding window preprocessing approach has the best predictive performance.

• Journal of the Korea Institute of Building Construction
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• v.13 no.4
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• pp.341-350
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• 2013

For this study, a series of interviews with engineers in the Korean construction industry was carried out through a formal workshop format to analyze the causes of the inferior quality of builders' hardware. The authors established the causes of defects in window hardware construction in relation to the three aspects of system, design, and construction as involving the following seven factors: lack of system (including low ability to create construction specifications); low social awareness of the importance of window hardware; low technical capability to create design drawings; low design costs; small manufacturing capacity; low construction cost; and short duration of construction. Among the seven causes, the biggest cause of defects in window hardware construction is the lack of a system (low ability to create construction specifications), followed by low technical capability to create design drawings. In addition, this study carried out basic research to create measures to prevent defects in window hardware construction by analyzing how such causes of defects are distributed depending on the scale of architectural firms and construction companies during actual projects.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.1
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• pp.18-24
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• 2007

If an error occurs in a product that contains a source of vibration, an abnormal noise vibration will occur. Recently a system that has been modified from the previous method of noise detection-a method of appraising the quality of manufactured automobile part by using human ears-is being implemented in the industries of automobile parts. This new system distinguishes the product's vibration signals by measuring and analyzing the signals. Following the recent trend, it has been concluded that the appraisal process of Window Regulator Module needed an improvement. Thus, a vibration monitoring system using LabVIEW, which measures and analyzes vibration signals from a sector gear's connected part by using an accelerometer, has been developed. By analyzing the characteristics of vibration signals of both inferior and superior goods, now the quality of the product can be evaluated much more accurately.

• Journal of Korean Institute of Architectural Sustainable Environment and Building Systems
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• v.12 no.6
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• pp.531-542
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• 2018

Building energy demands have highly risen in modern society; thus, It is necessary to reduce building energy demands especially commercial buildings adopting a curtain wall architecture. Curtain wall architectures have a high ratio of windows which is a vulnerable in heat insulations as cladding. In order to complement insulation performance of windows in these buildings, there are various methods adopted often such as installing blinds, wing wall and films. There are two suggestions of this paper. 1) WWR (Window-to-Wall Ratio) makes a impaction of energy demands in buildings. 2) Another one is an efficiency of blind systems which are installed in buildings in order to reduce cooling demands. It is also critical to make fundamental model for low-energy building construction by processing a lot of simulation As a result by this study, 1) an external blind system is more useful for reducing cooling energy demands rather than an internal blind system. 2) Buildings which have a large window require more amount of cooling demands. In case of WWR 45%, it needs more cooling energy rather than WWR 15% model's 3) Adopting blind system would reduce energy demands. WWR 45% model with external blind systems reduces about 4% of cooling energy demands compared to same model without any blind systems.4) it is necessary to study an efficiency of blind systems combined with renewable energy and it will be possible to reduce more energy demand in building significantly.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.17 no.3
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• pp.166-175
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• 2024

In this paper, the Window-Masking Method and HAT (Hardware Attached Top) CPU SoM (System on Module) are used to improve the performance and reduce the weight of the MANET (Mobile Ad-hoc Network) network synchronization system using time division redundancy. We propose converting it into a RISC-V based soft-core MCU and mounting it on an FPGA, a hardware accelerator. It was also verified through experiment. In terms of performance, by applying the proposed technique, the synchronization acquisition range is from -50dBm to +10dBm to -60dBm to +10dBm, the lowest input level for synchronization is increased by 20% from -50dBm to -60dBm, and the detection delay (Latency) is 220ns. Reduced by 43% to 125ns. In terms of weight reduction, computing resources (48%), size (33%), and weight (27%) were reduced by an average of 36% by replacing with soft-core MCU.

• Journal of Power System Engineering
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• v.21 no.5
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• pp.63-70
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• 2017

This paper deals with anti-pinch system based on current information which prevents some risks for trapping, squeezing or injury to people in smart window on vehicles. Automatic configuration of current threshold is suggested to recognize pinch states in the current based anti-pinch system. Also, some factors affecting to the squeezing force were analyzed by some experimental results and simulations. The validity of the suggested system was verified to satisfy the strengthened American safety regulation, FMVSS 118-S5, through some experimental results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.614-618
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• 2003

This paper presents a system identification (SI) scheme in time domain using measured acceleration data. The error function is defined as the time integral of the least square errors between the measured acceleration and the calculated acceleration by a mathmatical model. Damping parameters as well as stiffness properties of a structure are considered as system parameters. The structural damping is modeled by the Rayleigh damping. A new regularization function defined by the L$_1$-norm of the first derivative of system parameters with respect to time is proposed to alleviate the ill-posed characteristics of inverse problems and to accommodate discontinuities of system parameters in time. The time window concept is proposed to trace variation of system parameters in time.

• Korean Journal of Computational Design and Engineering
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• v.7 no.1
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• pp.18-26
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• 2002

The suggested modular projection system can have flexible arrangements of screens. Modular and continuous arrangements of the display system enable us to modify the screen configuration easily, so that the system can be used in various applications. The image of each screen is calculated automatically by using window projection and the tracked position of the viewer. This system also uses the off-axis stereoscopic projection for the seamless stereoscopic edge blending of multiple connections of screens. The system has been successfully tested for the general navigation model and the CAU driving simulator with motion platform.