• 한국입자에어로졸학회지
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• 제10권1호
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• pp.9-17
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• 2014

Several studies have been carried out on the source contribution of the particulate Polycyclic Aromatic Hydrocarbons (PAHs) over Seoul by using the Chemical Mass Balance Model (CMB)(Lee and Kim, 2007; Kim et al., 2013). To confirm the validity of the modeling results, the modified model employing a photochemical loss rate along with varying residence times and the standard model that considers no loss were compared. It was found that by considering the photochemical loss rate, a better performance was obtained as compared to those obtained from the standard model in the CMB calculation. The modified model estimated higher contributions from coke oven, transportation, and biomass burning by 4 to 8%. However, the order of the relative importance of major sources was not changed, coke oven followed by transportation and biomass burning. Thus, it was concluded that the standard CMB model results are reliable for identifying the relative importance of major sources.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1993년도 춘계학술대회논문집
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• pp.10-17
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• 1993

An object-oriented database was developed as a framesork for integrating into ergonomic interface models data for workplace modelling and ergonomic evaluation functions as well as basic anthropometric data required to construct a man model. In order to develop an ergonomic man model representing operators that interact with his working evnironments, not only anthro- pometric data but also efficient handling of such data and accurate representation of the work- space are needed as a prerequistite to proper ergonomic evaluation. Most existing man models are not, however, capable of fully utilizing these data due to the lack of a generallized formalism of data handling, which results in system performance degradation or a potential difficulty when the system is upgraded. In this research, these three sets of data with distinct characteristics were incorporated into a comon integrated database required to manipulate an ergonomic interface model fully coupled with the man model itself. An object- oriented scheme was sued for the database design Specifically, UniSQL/X, an object-oriented database management system and the X-window system on SPARC workstation were used for implementation. The ergonomic man model generated from the object-oriented database is found to possess great flexibility and performance compared to existing ergonomic interface models or ergonomic CAD systems.

• Earthquakes and Structures
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• 제25권1호
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• pp.57-67
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• 2023

The buckling of longitudinal reinforcements under seismic loading accelerates the degradation of the bearing capacity of reinforced concrete columns. The traditional hysteretic constitutive model of reinforcement, which does not consider buckling, usually overestimates the seismic performance of pier columns. Subsequent researchers have also proposed many models including the buckling effects. However, the accuracy of these hysteretic constitutive models proposed for simulating the buckling behavior is inadequate. In this study, based on their works, the influence of historical events on buckling is considered, the path of the re-tensioning phase is corrected by adjusting the boundary lines, and the positions of the onset buckling point and compressive buckling path during each buckling deformation are corrected by introducing correction parameters and a boundary line. A modified hysteretic constitutive model is obtained, that can more accurately reflect the buckling behavior of reinforcements. Finally, a series of hysteresis tests of reinforcements with different slenderness ratios were then conducted. The experimental results verify the effectiveness of the proposed modified model. Indicating that the modified model can more accurately simulate the equivalent stress-strain relationship of the buckling reinforcement segment.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1252-1252
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• 2022

Temporary work that utilizes temporary equipment (e.g., system scaffold and system pipe support) in construction work is one of the most vulnerable work from a safety perspective in South Korea. Typically, temporary equipment is reused at construction sites. The Korea Occupational Safety and Health Agency announced guidelines regarding the performance standards for reusable temporary equipment to prevent the accidental collapse of temporary facilities. Nevertheless, temporary facilities' collapse still occurs, which could be attributed to a degradation in the performance due to the reuse of temporary equipment. Therefore, this study investigated the performance of simple temporary structures assembled with new and reused equipment. To this end, an experimental module was designed based on previous research cases, and two experimental models were constructed, in which one was assembled using new equipment (Model A), and the other was built using reused equipment (Model B). To determine the performance of each model, a load test was conducted to measure the maximum load that each model could withstand. The experimental results revealed that the maximum load of Model B was 15% lower than that of Model A. This indicates that there is a meaningful performance difference between those two models. Based on this result, the authors decided to perform additional tests with more realistic models than previous ones. The new experimental module was designed to ensure compliance with the Korean design guidelines. In this presentation, the authors show details of the first tests and their results and plan for the additional test.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(1)
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• pp.115-118
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• 2000

In order to control the flow of traffics in ATM networks and optimize the usage of network resources, an efficient control mechanism is necessary to cope with congestion and prevent the degradation of network performance caused by congestion. To effectively control traffic in UNI(User Network Interface) stage, we proposed algorithm of integrated model using on-line teaming neural network for CAC(Call Admission Control) and UPC(Usage Parameter Control). Simulation results will show that the proposed adaptive algorithm uses of network resources efficiently and satisfies QoS for the various kinds of traffics.

• KIEE International Transactions on Electrophysics and Applications
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• 제5C권2호
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• pp.58-62
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• 2005

A trench MOS barrier Schottky (TMBS) rectifier is proposed which utilizes the upper half of the trench sidewall as an active area. The proposed structure improves the forward voltage drop by 20$\%$ in comparison with the conventional one without degradation in breakdown voltage. An analytical model for the field distribution is given and compared with two-dimensional numerical simulations.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.39.3-39
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• 2001

Since Kalman filter and wavelet transform techniques are both suitable for a nonstationary process, wavelet-Kalman filter was proposed and applied to various industrial fields. However, the wavelet-Kalman filter subjected to model uncertainty with nonstationary process has not been considered. Thus, the robust wavelet-Kalman filter method is proposed in this paper. The proposed method can prevent the degradation of filter performance when parameter uncertainty exists in both the state and measurement matrices and preserve the merits of the standard Kalman filter in the sense that it produces optimal estimates. A simple example shows that the proposed approach outperforms the standard Kalman filter and the nominal wavelet-Kalman filter.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.740-747
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• 2000

This paper describes insulation characteristics and partial discharge for the SF6 gas insulated transformer. The characteristic of gas insulated transformer and the degradation sequence of solid insulation under SF6 gas atmosphere were explained. The model electrode system of the types that the aramid papers were inserted between two sphere electrodes was prepared. The partial discharge tests were carried out to that system and the insulation characteristics were considered.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.216-222
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• 1998

Effects of translational and rotational motions of the foundation on the dynamic behaviors of a bridge under seismic excitations are examined by utilizing a simplified 3 degree-of-freedom of system. To consider the nonlinear characteristics of the RC pier, a hysteresis model is adapted, which can simulate the inelastic motion of the pier with the stiffness degradation. From results, the portion of the total displacement due to rotational motion of the foundation becomes larger as applied seismic excitation increases.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.216-221
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• 2002

A spherical Earth surface is used fur realistic analysis of the geometrical performance characteristics about the variation of satellite altitude and 2-dimensional line-of-sight(LOS) tilt angle in a satellite imager using Time Delay and Integration(TDI) technique with fixed integration time. In the spherical Earth surface model TDI synchronization using LOS tilt is investigated as a solution to compensate geometric performance degradation due to altitude decrease. This result can be used fur a TDI CCD imager with variable integration time in a certain as well.