• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.223-230
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• 2005

The unsteady nature of vortex structures has been investigated by a large eddy simulation (LES) in an axial flow fan with a shroud covering only the rear region of its rotor tip. The simulation shows that the tip vortex plays a major role in the structure and unsteady behavior of the vortical flow in the fan. The movements of the vortex structures induce high-pressure fluctuations on the rotor blade and in the blade passage. Frequency characteristics of the fluctuating pressure on the rotor blade are analyzed using wavelet transform. The dominant frequency of the real-time pressure selected at the high pressure fluctuation region corresponds well to that of the fluctuating rotor torque and the experimental result of fan noise. It is mainly generated due to the unsteady behavior of the vortical flow, such as the tip vortex and the leading edge separation vortex.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.10 no.3
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• pp.203-209
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• 2010

This paper presents a hierarchical fuzzy motion planner for humanoid robots in 3D uneven environments. First, we define both motion primitives and locomotion primitives of humanoid robots. A high-level planner finds a global path from a global navigation map that is generated based on a combination of 2.5 dimensional maps of the workspace. We use a passage map, an obstacle map and a gradient map of obstacles to distinguish obstacles. A mid-level planner creates subgoals that help the robot efficiently cope with various obstacles using only a small set of locomotion primitives that are useful for stable navigation of the robot. We use a local obstacle map to find the subgoals along the global path. A low-level planner searches for an optimal sequence of locomotion primitives between subgoals by using fuzzy motion planning. We verify our approach on a virtual humanoid robot in a simulated environment. Simulation results show a reduction in planning time and the feasibility of the proposed method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.1
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• pp.48-53
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• 2008

Twelve black seabreams (Acanthopagrus schlegeli) were tagged with acoustic transmitters and their movement and behavior patterns were tracked using acoustic telemetry from 12 December 2006 to 15 August 2007. Seven of the 12 fish stayed within 500 m of the release point for over a month. In the spring tide, the number of detected signals and swimming depth of tagged fish changed at 12-hour intervals with the ebb tide. The number of detected signals of tagged fish decreased dramatically with the passage of time and had decreased by over 80% in May 2007, compared with January 2007.

• Journal of Power System Engineering
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• v.9 no.1
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• pp.23-29
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• 2005

Numerical analysis of three-dimensional viscous flow-fields in the turbine rotor passages was carried out to investigate flow physics including the interaction between secondary vortices, tip leakage vortex, and the rotor wake. The blade tip geometry was accurately modeled adopting the embedded H grid system. An explicit four-stage Runge-Kutta scheme was used for the time integration of both the mean flow and turbulence equations. The computational results for the entire turbine rotor flows, particularly the tip clearance flow and the secondary flows, were interpreted and compared with the experimental data from the Penn State turbine stage. The predictions for major features of the flow field have been found to be in good agreement with the experimental data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.562-567
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• 2012

Noises from the large scale marine propeller are calculated numerically on non-cavitation condition. The hydrodynamic analysis are carried out by potential based panel method with time marching free wake approach. The distribution of hyrodynamic loads on the propeller surface and noise signals are obtained using the unsteady Bernoulli's equation and the Farasssat formula respectively. It turns out that the noise signal shows strong peak at the blade passage frequency. Noise signals and directivity patterns for both the thickness and the loading noise are compared with each other. The directivity pattern for the loading noise shows minor lobe at the backward side of the rotating disc plane.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.5
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• pp.668-677
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• 2004

This study examines the effects and influences of fumigation on the antimicrobial treatment of excavated dresses in two different museum settings using chemical composite of Methyl Bromide and Ethylene Oxide. The microbial test indicated that the prewashed samples contained Micrococcus, Bacillus, Staphylococcus, and some unidentified fungi and that the total number of microbes decreased after washing. While it was observed that most germs were removed immediately after fumigation, Bacillus was still found and its number even increased. After 5 months, the number of microbes found in Museum A was smaller than Museum B, which shows that Museum A equipped with better environment control facility was superior to Museum. B in terms of exhibition and preservation of dresses against organic damages. In addition, the result indicates that fumigation is an effective measure against the growth and reproduction of microorganisms, considering that the number of microorganisms decreased after fumigation. The color of test sample showed immediate change after fumigation but color difference became stabilized and decreased with the passage of time. The test samples from both museums showed similar patterns.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.147-152
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• 2003

Passage of time axial shortening in the cores and columns of tall concrete buildings requires special attention to ensure proper behavior for strength of the structure and the nonstructural element. The effects of column shortening, both elastic and inelastic, take on added significance and need special consideration in design and construction with increased height of structures. In this paper, the compensation method of column shortening for reinforced concrete structure are introduced. It could be concluded that the survey is a significant factor for the compensation instance of column shortening.

• International Journal of Railway
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• v.7 no.2
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• pp.46-56
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• 2014

The superstructure of the railway track undertakes the forces that develop during train passage and distributes them towards its seating. The track panel plays a key role in terms of load distribution, while at the same time it maintains the geometrical distance between the rails. The substructure and ballast undergo residual deformations under high stresses that contribute to the deterioration of the so-called geometry of the track. The track stiffness is the primary contributing factor to the amount of the stresses that develop on the substructure and is directly influenced by the fastening resilience. Four methods from the international literature are used in this paper to calculate the loads and stresses on the track substructure and the results are compared and discussed. A parametric investigation of the stresses that develop on the substructure of different types of railway tracks (i.e. balastless vs ballasted) is performed and the results are presented as a function of the total static track stiffness.

• YAKHAK HOEJI
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• v.33 no.3
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• pp.149-155
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• 1989

To predict the influence of carbon monoxide poisonining on cerebral energy metabolism, rats were exposed to 5000 ppm environment for 30 minutes. Carboxyhemoglobin (HBCO) saturation rate in this condition was 72% equally in male and female rats. Cerebral cortex in the rats showed lower level of ATP, glucose, creatine phosphate and higher level of lactate, pyruvate by anaerobic glycolysis. As for the levels of ATP, creatine phsphate and glucose, the cerebral cortex contents of them were larger in female rats of estrus than in male rats, whereas there was no difference between sexes in the levels of pyruvate and lactate. According to time passage from CO intoxication, the mode of changes in cerebral energy metabolite contents was similar in both sexes.

• Korean Journal of Veterinary Research
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• v.10 no.2
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• pp.21-51
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• 1970

Series of experiments were conducted to determine lethal does of X-ray and Neutron on Toxoplasma gondii. strain RH and IRI. As well morphological changes of Toxoplasma gondii irradiated or not were compared by use of electron microscope. The pathogenicity test of the irradiated and nonirradiated Toxoplasma gondii was made in mice guinea-pigs, rabbits and pigs: The letahl dose of X-ray and Neutron on RH and IRI strain and the growth rate between two strains after irradiation were shown little differences. Morphological changes were not observed until 18th passage was made. After then, the growth rate was decreased apparently, and atrophied forms were frequently observed in electron microscope. Survival time of animals inoculated with irradiated strain was longer than that of animals giving non-irradiated strain, and Toxoplasma gondii were isolated from all the dead animals. But it is of interest that pigs survived after injection of Toxoplasma gondii remained health and much attempts were failed toisolate Toxplasma gondii remained health and much attempts were slaughtered them. Animals were succumbed after injection of Toxoplasma gondii without any relationship with serum titers. (HA antibody).