• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1996.10a
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• pp.7-9
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• 1996

A simple two-and -half-layer model is used to study the circulation of South China Sea( SCS ). The model is coming from the reduced gravity model of Hurbult and Thompson, with the assumption of rigid surface. It shows there is no distinct branch of the Kuroshio into the SCS. Both the upper and lower pycnocline height anomaly show that the main feature of the circulation of SCS is a cyclone, which is generated by the transportion of the vorticity from the Kuroshio. Aftr generated, the cyclone moves westward due to the beta effect, then dissipates near the west boundary due to the viscosity. After an old one dissipates, a new one appears again. The life cycle of the cyclone is about 160 days.

• Management Science and Financial Engineering
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• v.13 no.2
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• pp.99-116
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• 2007

This paper considers the value of location in a linear city model and examines the product differentiation equilibrium of duopoly providing different benefits to consumers. We show that if the value of location is small, symmetric location equilibrium occurs where two firms follow the maximal differentiation principle. However, as the value of location increases, asymmetric location equilibrium occurs where the low-value-location firm moves to the high-value-location firm and thus adjusted maximal differentiation principle holds. We also investigate two different price leadership model and demonstrate the relationship between the value of location and the role of price leadership. In particular, we show that when the location value is high, the price leadership by high-value-location firm will appear as a unique equilibrium.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1308-1311
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• 1996

We propose a new linearized model which can be used very efficiently for the design and analysis of the autopilot of aerodynamically controlled skid-to-turn missiles. Proposed model is based on the linearized equations of the missile dynamics derived in the aerodynamic frame where xz plane contains the missile longitudinal axis and velocity vector. However, to take the effect due to the small perturbation of the missile body into consideration, we introduce a new frame which is identical to the aerodynamic frame in the trim state but after small perturbation it moves fixed with the missile body, and finally, the proposed model is set up in this frame. It is shown by nonlinear simulations and stability analysis of a numerical example that the new model describes the missile motion better than the conventional one linearized in the body frame with a certain amount of simplification.

• Structural Engineering and Mechanics
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• v.13 no.5
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• pp.505-532
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• 2002

In this study, the analysis of high-speed vehicle-bridge interactions by a simplified 3-dimensional finite element model is performed. Since railroads are constructed mostly as double tracks, there exists eccentricity between the vehicle axle and the neutral axis of cross section of a railway bridge. Therefore, for the more efficient and accurate vehicle-bridge interaction analysis, the analysis model should include the eccentricity of axle loads and the effect of torsional forces acting on the bridge. The investigation into the influences of eccentricity of the vehicle axle loads and vehicle speed on vehicle-bridge interactions are carried out for two cases. In the first case, only one train moves on its track and in the other case, two trains move respectively on their tracks in the opposite direction. From the analysis results of an existing bridge, the efficiency and capability of the simplified 3-dimensional model for practical application can be also verified.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.04a
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• pp.221-224
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• 2005

This paper proposes the system model that is more efficient and active than formal home automation system and it can conquer the limits of formal one using intelligent mobile robot. This system uses specialized intelligent mobile robot for home environment and the robot moves around home instead of human. We call the system model to HAuPIRS (Home Automation system using PDA based Intelligent Robot System). HAuPIRS control architecture is composed three parts and each part is User Level, Cognitive Level, Executive Level. It is easy to use system and possible to extend the home apparatusfrom new technology. We made the PBMoRo System (PDA Based Mobile Robot System) based on HAuPIRS architecture and verified the efficiency of the system model.

• International Journal of Advanced Culture Technology
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• v.7 no.4
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• pp.229-235
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• 2019

Due to the development of video and optical technology today, video equipments are being used in a variety of fields such as identification, security maintenance, and factory automation systems that generate products. In this paper, we investigate an algorithm that effectively recognizes an experimental object in an input image with a partial problem due to the mechanical problem of the input imaging device. The object recognition algorithm proposed in this paper moves and rotates the vertices constituting the outline of the experimental object to the positions of the respective vertices constituting the outline of the DB model. Then, the discordance values between the moved and rotated experimental object and the corresponding DB model are calculated, and the minimum discordance value is selected. This minimum value is the final discordance value between the experimental object and the corresponding DB model, and the DB model with the minimum discordance value is selected as the recognition result for the experimental object. The proposed object recognition method obtains satisfactory recognition results using only partial information of the experimental object.

• International journal of advanced smart convergence
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• v.11 no.3
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• pp.64-71
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• 2022

Various types of attendance management systems are being introduced in a remote working environment and research on using face recognition is in progress. To ensure accurate worker's attendance, a face recognition-based attendance management system must analyze every frame of video, but face recognition is a heavy task, the number of the task should be minimized without affecting accuracy. In this paper, we proposed a search model using time interval variation to minimize the number of face recognition task of recorded videos for attendance management system. The proposed model performs face recognition by changing the interval of the frame identification time when there is no change in the attendance status for a certain period. When a change in the face recognition status occurs, it moves in the reverse direction and performs frame checks to more accurate attendance time checking. The implementation of proposed model performed at least 4.5 times faster than all frame identification and showed at least 97% accuracy.

• Journal for History of Mathematics
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• v.36 no.6
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• pp.105-113
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• 2023

We will suggest a train model to explain the weekly periodic character of Covid19 in South Korea on the first half of 2022, the period of the Omicron variant outbreak. In the model, the daily new infected individuals board a train, divided into 4 compartments. The train moves at night by the length of one compartment. Then the infected are quarantined during the daytime after their compartment reaches the quarantine area. Then it remains empty on the 5-th night after boarding. The parameters of the model are fitted with the daily measured quarantine populations and generate the simulated quarantine populations that hit the real weekly and global peaks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2473-2492
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• 2012

Energy conservation is a vital issue in wireless sensor networks. Recently, employing mobile sinks for data gathering become a pervasive trend to deal with this problem. The sink can follow stochastic or pre-defined paths; however the controlled mobility pattern nowadays is taken more into consideration. In this method, the sink moves across the network autonomously and changes its position based on the energy factors. Although the sink mobility would reduce nodes' energy consumption and enhance the network lifetime, the overhead caused by topological changes could waste unnecessary power through the sensor field. In this paper, we proposed EEDARS, an energy-efficient dual-sink algorithm with role switching mechanism which utilizes both static and mobile sinks. The static sink is engaged to avoid any periodic flooding for sink localization, while the mobile sink adaptively moves towards the event region for data collection. Furthermore, a role switching mechanism is applied to the protocol in order to send the nearest sink to the recent event area, hence shorten the path. This algorithm could be employed in event-driven and multi-hop scenarios. Analytical model and extensive simulation results for EEDARS demonstrate a significant improvement on the network metrics especially the lifetime, the load and the end-to-end delay.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.3
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• pp.125-135
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• 2017

Various seismic isolation methods are being applied to bridges and buildings to improve their seismic performance. Most seismic isolation systems are the structural seismic isolation systems. In this study, the seismic performance of geotechnical seismic isolation system capable of isolating the lower foundation of the bridge structure from ground was evaluated. The geotechnical seismic isolation system was built with teflon, and the model structure was made by adopting the similitude law. The response acceleration for sinusoidal waves of various amplitudes and frequencies and seismic waves were analyzed by performing 1-G shaking table experiments. Fixed foundation, Sliding foundation, and Rocking foundation were evaluated. The results of this study indicated that the Teflon-type seismic foundation isolation system is effective in reducing the acceleration transmitted to the superstructure subject to large input ground motion. Response spectrum of the Rocking and Sliding foundation structures moves to the long period, while that of Fixed foundation moves to short period.