• Magazine of the Korean Society of Agricultural Engineers
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• v.19 no.4
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• pp.4544-4554
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• 1977

The objective of this study was to measure and compare the radiation heat load generated through a few chosen shade-materials that would protect animals from the direct solar radiation heat in summer condition. The results obtained from this study are as follows; 1. when the materials were used in original state, the most effective material for radiation heat reduction was slate, followed by aluminum and galvanized steel successively. 2. The radiation heat load under the white top and black underside aluminum was 2.5 Cal. per hour per square cm less than that under the bare aluminum of their diurnal peak. 3. When the modified galvanized steel was used, the radiation heat load was reduced as much as 2.4 cal per hour per square cm by attaching plywood under the galvanized steel, 3.9 cal per hour per square cm by attaching plywood and coating white paint on the top of the galvanized steel. The galvanized steel covered by hay material showes similar result as that of the galvanized steel lined with plywood. 4. In case of slate, the radiation heat reduction value was increased by using bare slate, white top slate and white-top-black-underside slate in the descending order. 5. The calculated value of radiosity of inside surface of aluminum was about 20 percent of the radiation heat load, the reduced value of radiosity by coating paint was considered to be indirect indication of the effect of total radiation heat load reduction of painted surface. 6. About an hour of the time lag of radiation heat load peak on sept. 10 for slate materials should be investigated more comprehensively in future.

• Journal of the Korean Geotechnical Society
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• v.27 no.12
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• pp.85-96
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• 2011

A breakwater is a important structure for both calmness of harbor and protection of the port facilities from waves generated from typhoons or wind. This study adopted the rubble mound breakwater, which is one of the most popular type of breakwaters in Korea. Rubble mound breakwater had been designed by considering only static condition previously. Recently, a dynamic wave-load due to waves has been also considered in designing breakwater. In design, the wave-load is assumed as an uniform load which only acts in the front slope of the breakwater. However, the assumption is not applicable in reality. In this study, therefore, a real-time wave-load acting on the breakwater instead of the uniform load is considered, and it is assumed to be acting on the seabed too. Based on the numerical analysis, it is found that there is a significant difference in the maximum settlement compared with the result predicted by the existing design method.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.5
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• pp.312-325
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• 2006

Integration applications, such as EAI, B2Bi, need stable massive data processing systems during overload state cause by service request congestion in a short period time. In this paper, we propose the PLC (Peak Load Control)-based Worker-Linker pattern, which can effectively and stably process massive I/O transactions in spite of overload state generated by service request congestion. This pattern uses the delay time algorithm for the PLC mechanism. In this paper, we also show the example of applying the pattern to business-business integration framework and the experimental result for proving the stability of performance. According to our experiment result, the proposed delay time algorithm can stably control the heavy overload after the saturation point and has an effect on the controlling peak load.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.10
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• pp.773-778
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• 2012

A road energy harvester was designed and fabricated to convert mechanical energy from the vehicle load to electrical energy. The road energy harvester is composed of 16 piezoelectric cantilevers. We fabricated prototypes using a vehicle load transfer mechanism. Applying a vehicle load transfer mechanism rather than directly installing energy harvesters under roads decreases the area of road construction and allows more energy harvesters to be installed on the side of the road. The power generation amount with respect to the vehicular velocity change was assessed by installing the vehicle load transfer mechanism form and underground form. The energy harvester installed in the underground form generated power of 4.52 mJ at the vehicular velocity of 50 km/h. Also, power generation of the energy harvester installed in the vehicle load transfer mechanism form was 48.65 mJ at the vehicular velocity of 50 km/h.

• Tunnel and Underground Space
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• v.26 no.3
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• pp.192-200
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• 2016

We analyzed the behavior of the lining segments considering the middle slab and lateral pressure coefficients when planning the construction of a duplex tunnel for the underground network. Reviewed segment lining analysis for research, the analytical model was determined for duplex tunnel. Also reviewed the vertical load, and a load of middle slab is considered the static load and the live load by vehicles. Section force by middle slabs a load applied was mainly generated in the lower tunnel had the greatest effect on the bending moment. In addition, the bending moment acting direction changes appeared with a large variable, and the section force according to the load applied to the middle slab is relatively constant and the effect on the segment lining from the smallest section force of the lateral pressure coefficient of 1.00 was found to occur appears most significantly. As a result of this research to identify the behavior of the slab and the segment lining by the effect of the lateral pressure coefficient (K) of the duplex tunnel will be able to present a method of the duplex tunnel structure is reasonable and economical design.

• Journal of Korea Entertainment Industry Association
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• v.14 no.4
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• pp.365-370
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• 2020

The purpose of this study was to accurately measure the load generated on the leg according to the position of the sling strap supporting the leg during the sling bridge exercise for improvement of life care. Ten Healthy university students participated in two trials: knee bridge exercise and ankle bridge exercise in supine position. The loads transmitted to the knees and ankles were measured when a bridge exercise was performed with a sling strap on both knees and ankles. As a result of the study, it was confirmed that the load of sling bridge exercise with both knees supported was statistically greater than the load of sling bridge exercise with both ankles supported(p<.01). On the other hand, there was no statistically significant difference in the load between both knees and both ankles (p>.05). Therefore this study is meaningful in that it objectively measured the load on the leg during sling bridge exercise, and is thought to be helpful in setting exercise intensity during sling exercise.

• Tribology and Lubricants
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• v.39 no.2
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• pp.81-85
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• 2023

This study presents an experimental investigation of the effects of surface roughness on gas foil thrust bearing (GFTB) performance. A high-speed motor with the maximum speed of 80 krpm rotates a thrust runner and a pneumatic cylinder applies static loads to the test GFTB. When the motor speed increases and reaches a specific speed at which a hydrodynamic film pressure generated within the gap between the thrust runner and test GFTB is enough to support the applied static load, the thrust runner lifts off from the test GFTB and the friction mechanism changes from the boundary lubrication to the hydrodynamic lubrication. The experiment shows a series of lift-off test and load-carrying capacity test for two thrust runners with different surface roughnesses. For a constant static load of 15 N, thrust runner A with its lower surface roughness exhibits a higher start-up torque but lower lift-off torque than thrust runner B with a higher surface roughness. The load capacity test at a rotor speed of 60 krpm reveals that runner A results in a higher maximum load capacity than runner B. Runner A also shows a lower drag torque, friction coefficient, and bearing temperature than runner B at constant static loads. The results imply that maintaining a consistent surface roughness for a thrust runner may improve its static GFTB performance.

• Tribology and Lubricants
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• v.40 no.5
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• pp.151-156
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• 2024

Gas foil thrust bearings (GFTBs) support axial loads in oil-free, high speed rotating machinery using gas as a lubricant. However, under low-speed and high-load conditions, such a bearing experiences friction, leading to wear and a reduced lifespan. Therefore, a pressurized GFTB (PGFTB) that combines hydrostatic and hydrodynamic lubrication by supplying pressurized gas through the supply hole of the top foil has been developed, and various studies have been conducted. In this study, we develop mathematical models of PGFTBs with sloped and stepped recesses and predict its load support performance. The PGFTB maintains a minimum film thickness of approximately 20 ㎛ at rest (0 rpm), regardless of the type of recess, indicating a sufficient hydrostatic pressure to lift the runner at a low rotor speed. Furthermore, the minimum film thickness increases slightly as the numbers of feed holes in the in- and outward radial directions relative to the centerline of the PGFTB pad increase. These findings highlight the importance of supply hole placement in enhancing load support performance. As the rotor speed increases, the minimum film thickness increases rapidly, regardless of the number of supply holes, and without pressurization, sufficient hydrodynamic pressure is generated to lift the runner upon exceeding a certain rotor speed. When comparing the sloped and stepped recesses, the PGFTB with the sloped groove exhibits a superior overall load support performance.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.162-168
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• 2014

Use of nonlinear loads, such as power converters, fluorescent lamps and adjustable speed motor drives, is expected to grow rapidly. All of these loads inject harmonic currents. This paper presents the active filtering of the harmonic distortion generated by the compact fluorescent lamps (CFL). The Instantaneous active and reactive power theory (the p-q Theory) is used to design the control of parallel active filter. The control scheme has been verified using Matlab/Simulink with SimPower Systems through a set of simulation tests under different load conditions. Also, the tuning of the active power filter is performed to improve the quality of the electrical power supply.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.3
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• pp.53-67
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• 1994

This paper describes the design of a high-level synthesis system. SODAS-VP. which automatically generates hardwares executing operation sequences in pipelined fashion.Target architecture and clocking schemes to drive pipelined datapath are determined, and the handling of pipeline hazards which degrade the performance of pipeline is considered. Partitioning of an operation into load, operation, and store stages, each of which is executed in partitiones control step, is performend. Pipelinecl hardware is generated by handling pipeline hazards with internal forwarding or delay insertion techniques in partitioning process and resolving resource conflicts among the partitioned control steps with similarity measure as a priority function in module allocation process. Experimental results show that SODAS-VP generates hardwares that execute faster than those generated by HAL and ALPS systems. SODAS-VP brings improvement in execution speed by 17.1% and 7.4% comparing with HAL and ALPS systems for a MCNC benchmark program, 5th order elliptical wave filter,respectively.