• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.130-135
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• 2020

This paper describes the results of a study on the unmanned cleaning robot that performs the cleaning of the floating photovoltaic panels. The robot uses two SSC (Sliding Suction Cup) adsorptive devices to move up and down the slope. First, the forces generated when the robot moves up the slope are mechanically analyzed. The robot was designed and manufactured to operate stably by using the presented results. Next, the robot motion was tested on the inclined panel. It has been proven that robots are well designed and built to clean sloped panels.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1740-1746
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• 2008

The present study performed numerical investigation to analyze the smoke behavior in the rescue station by using the commercial CFD code (FLUENT Ver 6.3). The present study adopted a 10MW ultrafast mode for simulation, and it also used the MVHS(Modify Volumetric Heat Source) model modified from the original VHS(Volumetric Heat Source) model in order to treat the product generation and the oxygen consumption under the stoichiometric state. In addition, the present simulation includes the species conservation equation for the materialization of heat source and the estimation of smoke movement. From the results, the smoke flows are moving along the ceiling because of thermal buoyancy force and as time goes, the smoke gradually moves downward at the vicinity of the entrance. Moreover, without using ventilation, it is found that the smoke flows no longer spread across the cross-passages because the pressure in the non-accident tunnel is higher than that in the accident tunnel.

• Journal of the Semiconductor & Display Technology
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• v.3 no.4
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• pp.13-17
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• 2004

As the usage of wireless LAN becomes common in working environment, the number of database systems that support both wired and wireless users increases rapidly. The characteristics of wireless LAN that its speed is slow relatively comparing to wired network and the users in its environment connects to different communication points as they moves creates another challenge to be resolved in database systems. In the environment of hybrid communication systems, wired and wireless for voluminous data amount and a number of users, the two layer architecture of the conventional client-server database systems has limitation in the system performance. This is due to that server is the only point of data service in client-server database systems. In this paper, we discuss a new extended database system architecture that data services are distributed among servers and clients based on user database access patterns in order to improve system performance. We analyze the expected system performance by using simulation technique and prove the practical utilization of the system by demonstrating experimental results.

• Solar Energy
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• v.19 no.3
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• pp.115-123
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• 1999

An experimental study was carried out to investigate the flow characteristics of a stationary blade for six kinds of measuring angles of attack, $0^{\circ},\;10^{\circ},\;20^{\circ}\;and\;30^{\circ}$ at Reynolds number of $5.8{\times}10^4$. Instant simultaneous velocity vectors around blade were measured by 2-D PIV system where laser-based illumination and two-frame grey-level cross correlation algorithm were adopted. Velocity profiles show uniform approaching flow from the straightening equipment, and experimental results reveal that separation phenomena occur and the separation point moves upstream with increasing angle of attack.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.3
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• pp.67-75
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• 1998

This paper presents a new robot motion planning method for moving obstacle avoidance. To consider the mobility of a moving obstacle, we define virtual distance function(VDF) between the robot and the obstacle. At each sampling time, we use the VDF to construct an artificial potential, considering the motion of obstacles. The robot moves according to the repulsive and attractive force vector induced by the artificial potential function. The proposed algorithm can be driven the robot to avoid moving obstacles in real time. Some simulation studies show the effectiveness of the proposed method.

• Fashion & Textile Research Journal
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• v.9 no.3
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• pp.327-335
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• 2007

As the digital environment gets ubiquitous, domestic and international research and development on smart clothing is being conducted actively these days. However, most research is being carried out with its center on upper garment. So research on lower garment is insufficient even though it affects wearer's activity and comfort to a great extent when digital devices are attached or wearers moves their body. Therefore, the type of clothes this research proposes is men's formal pants which have an electrically-vibrating wearable device. These are smart pants which are helpful in easing muscle pain with their massaging effect in daily life. For this purpose, this research intends to develop patterns considering the body shapes and movements of wearers and suggest a tentative structure plan for smart pants where a vibration device is attached, which is mainly composed of vibrating motor, controller, and switch, and considered their bulks, numbers, attaching places.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.247-252
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• 2001

In this paper, dynamic modeling and its analysis for the PIG flow through $90^{\circ}$ curved pipe with compressible and unsteady flow are studied. The PIG dynamics model is derived by using Lagrange equation under assumption that it passes through 3 different sections in the curved pipeline such that it moves into, inside and out of the curved section. The downstream and up stream flow dynamics including the curved sections are solved using MOC. The effectiveness of the derived mathematical models is estimated by simulation results for a low pressure natural gas pipeline including downward and upward curved sections. The simulation results show that the proposed model and solution can be used for estimating the PIG dynamics when we pig the pipeline including curved section.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2658-2663
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• 2008

In the present study, we designed a microfluidic flatform that generates monodisperse droplets with diameters ranging from hundreds of nanometers to several micrometers. To generate fine droplets, T-junction and flow-focusing geometry are integrated into the microfluidic channel. Relatively large aqueous droplets are generated at the upstream T-junction and transported toward the flow-focusing geometry, where each droplet is broken up into the targeted size by the action of viscous stresses. Because the droplet prior to rupture blocks the straight channel that leads to the flow-focusing geometry, it moves very slowly by the pressure difference applied between the advancing and receding regions of the moving droplet. This configuration enables very low flow rate of inner fluid and higher flow rate ratio between inner and outer fluids at the flow-focusing region. It is shown that the present microfluidic device can generate droplets with diameters about 1 micrometer size and standard deviation less than 3%.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.11a
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• pp.3-7
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• 2005

The structure of $IP^2$(IP based-IMT Network Platform) as ubiquitous platform is three-layered model : Middleware including NCPF(Network Control Platform) and SSPF(Service Support Platform), IP-BB(IP-Backbone), Access network including Sensor network. A mobility management(MM) architecture in NCPF is proposed for $IP^2$. It manages routing information and location information separately. The existing method of multicast control in $IP^2$ is Remote Subscription. But Remote Subscription has problem that should be reconstructed whole Multicast tree when sender moves. To solve this problem, we propose a way to put Multicast Manager in NCPF.

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.144-149
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• 2019

This paper describes the results of a study on the unmanned maintenance robot that simultaneously performs the cleaning and inspection of the photovoltaic panels. The robot has a special adsorptive device, an infrared sensor, a vacuum level sensor and a camera. The robot uses two SSC (Sliding Suction Cup) adsorptive devices to move up and down the slope. First, the forces generated when the robot moves up the slope are mechanically analyzed, and the required design and control of the adsorption system are suggested. The robot was designed and manufactured to operate stably by using the presented results. Next, the normal force between the panel and the wheel was measured to confirm that the robot was manufactured and operated as intended, and the robot motion was tested on the inclined panel. It has been proven that robots are well designed and built to clean and inspect sloped panels.