• Journal of ILASS-Korea
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• v.13 no.1
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• pp.9-15
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• 2008

This experimental study was carried out to examine the heat transfer characteristics of impinging air jet on a flat plate with a set of right angled triangle rods. Each right angled triangle rod in the array was positioned normal to the flow direction and parallel to the flat plate surface. The clearances from a right angled triangle rod to flat plate surface (C=1, 2 and 4 mm) and the distance from nozzle exit to flat plate (H=100 and 500 mm) were changed for the pitch between each right angled triangle rods (P=40 mm). As a result, heat transfer shows best performance at the clearance of C=1 mm, in case clearance changed, and the average heat transfer enhancement rate increased up to 47% compared to the result of a flat plate without a right angled triangle rod.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.235-241
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• 2002

The process of energy separation in a low pressure vortex tube with air as a working medium is studied In detail. Experimental data of the temperature of the cold and hot air leaving the vortex tube are presented. The variation of the maximum wall temperature along the inner surface of the vortex tube and the temperature distribution in the vortex tube provides useful information about the location of the stagnation point of the flow field at the axis of the vortex tube. In this study Outer tube is used for the application of Diesel engine exhaust. The hot gas flow is fumed 180° and passes the outside of the vortex tube a second time heating it. From this geometric setup of a vortex tube the effects of energy separation and the prediction of the ignition of Diesel Soot is presented by experimental data.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.61-65
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• 2002

Nonpremixed counterflow flames at low strain rates, $ag=12s^{-1}$ and $12s^{-1}$, were numerically simulated to investigate the effects of the duct thickness on the flame structure in normal gravity. For small values of the duct thickness, the positions of the flame and stagnation point were highly sensitive to the duct thickness. When the duct thickness was greater than 6mm, however, the effects of the duct thickness on the flame structure were negligible. The computed temperature along the duct centerline agreed well with measurements.

• Wind and Structures
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• v.29 no.1
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• pp.55-64
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• 2019

The effect of vortex impingement on the fluid dynamics around a cylinder submerged in the wake of another of different diameters is numerically investigated at a Reynolds number Re = 200. While the diameter (D) of the downstream cylinder is fixed, impinging vortices are produced from the upstream cylinder diameter (d) varied as d/D = 0.24, 0.4, 0.6, 0.8 and 1.0, with a spacing ratio L=5.5d, where L is the distance between the center of the upstream cylinder to the front stagnation point of the downstream cylinder. Two-dimensional simulations are carried out using the finite volume method. Fluid forces acting on the two cylinders are correlated with impinging vortices, vortex shedding, and wake structure. Different facets of wake formation, wake structure, and flow separation and their connections to fluid forces are discussed.

• Journal of Information Processing Systems
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• v.16 no.6
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• pp.1309-1323
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• 2020

Crowd evacuation simulation is an important research issue for designing reasonable building layouts and planning more effective evacuation routes. The social force model (SFM) is an important pedestrian movement model, and is widely used in crowd evacuation simulations. The model can effectively simulate crowd evacuation behaviors in a simple scene, but for a multi-obstacle scene, the model could result in some undesirable problems, such as pedestrian evacuation trajectory oscillation, pedestrian stagnation and poor evacuation routing. This paper analyzes the causes of these problems and proposes an improved SFM for complex multi-obstacle scenes. The new model adds navigation points and walking shortest route principles to the SFM. Based on the proposed model, a crowd evacuation simulation system is developed, and the crowd evacuation simulation was carried out in various scenes, including some with simple obstacles, as well as those with multi-obstacles. Experiments show that the pedestrians in the proposed model can effectively bypass obstacles and plan reasonable evacuation routes.

• Steel and Composite Structures
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• v.43 no.2
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• pp.221-228
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• 2022

Two-dimensional stagnation point slip flow of a Casson fluid impinging normally on a flat linearly shrinking surface is considered. The modeled PDEs are changed into nonlinear ODEs through appropriate nonlinear transformations.The flow is assumed to be steady and incompressible, with external magnetic field acting on it. Similarity transformation is utilized to investigate the behavior of many parameters for heat and velocity distributions using truncation approach.The influence of buoyancy parameter, slip parameter, shrinking parameter, Casson fluid parameter on the heat profile. The effect of the magnetic parameter on the streamwise velocity profile is also investigated.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.11 no.4
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• pp.1-5
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• 1982

In this paper, a study is made of the steady laminar free convection boundary-layer equations on a sphere with uniform surface heat flux. To solve the boundary-layer equations, well-known Pohlhausen's simiarity solution for vertical plates is adopted just the same for spherical bodies by introducing twonondimensional parametric functions, so called azimuth functions. To determine the values of the azimuth functions which are expressed in series at the two points (the upper stagnation point and the equator), trial and error method is required. It is concluded that the heat transfer results are in good agreement with obtained from perturbation method and Von Karman-Pohlhausen method within the steady laminar free convection region for Pr=0.70.

• Asia Marketing Journal
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• v.11 no.2
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• pp.53-72
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• 2009

In the summer of 2008, the movie Dachimawa Lee: Villain, Get on the Express to Hell is waiting for its first release. This movie is based on a short film which was tremendously popular when it was first introduced on the internet in 2000, and the director Ryu Seung Wahn is expecting a mega hit of the movie this summer. Showbox is one of the leading movie distributors in Korea. After a series of blockbuster hits such as Welcome to Dongmakgol, The Host, and The Chaser, Showbox is now in stagnation. Along with sluggish economy in Korea, most of recent movies distributed by them didn't even reach the breakeven. However, expectation on the upcoming movie, Dachimawa Lee, is higher than ever. Marketing department of Showbox has to decide what kind of media channel to choose and which marketing strategy to apply. It needs to make a decision about whether to target the so-called mania group or the general public of much bigger size. In this case study, the distinctiveness of the movie marketing and its process will be discussed. Moreover, the marketing strategies for Dachimawa Lee's success will be examined in the Showbox's point of view.

• Journal of Industrial Technology
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• v.43 no.1
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• pp.33-41
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• 2023

This paper provides a general overview of surface catalytic recombination in hypersonic flow. The surface catalytic recombination phenomena is elaborated in terms of its general overview and numerical modeling associated with it. The general overview of the surface catalytic recombination phenomena describes the elementary surface reactions for the surface catalytic and the role of the surface catalytic recombination efficiency in the heat transfer determination. In the numerical modeling, the surface catalytic recombination is described based on the stagnation-point boundary layer analysis, and finite-rate surface reaction modeling. Throughout this overview manuscript, a general understanding of this phenomena is obtained and can be used as foundation for deeper application with the numerical computational fluid dynamics (CFD) flow solver to estimate the surface heat transfer in the hypersonic vehicles.

• Journal of Oriental Neuropsychiatry
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• v.8 no.2
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• pp.85-95
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• 1997

After performing the auricular acupuncture therapy for the functional headache, we came to gain the following therapy effects. 1. In the whole of the patients of the functional headache, housewives of forties were most of all. 2. In the classification of mordern medicine on the patients of the functional headache, muscular contractional headache was most of all and in the classification of oriental differentiation of symtoms and signs(辨證), headache due to deficiency of blood(血虛頭痛) was most of all. 3. In the regional auricular acupuncture therapy for the functonal headache, Taiyang of auricular point(太陽點) had an effect on the lateral headache around the area of Taiyang of auricular point(太陽點) though the actions of sedation, analgesia, Neck of auricular point(頸點) had an effect on the muscular contractional headache of the occipital region, and Stomach of auricular point(胃點) had an effect on the headache of stagnation of phlegm(痰濁頭痛) of anterior region with a chronic digestive disease. 4. The average treatment times of the auricular acupuncture therapy in the patients of the functional headache was 4.08 times, if we have them take auricular acupuncture therapy about 4 times it could be thought to take excellent effect of treatment. 5. The effect of auricular acupuncture therapy for functional headache was turned out to be effective in the following orders ; lateral region(Group A), occipital region(Group B), anterior region(group C). Through the clinical consequences of therapy mentioned above, we came to confirm regular therapeuric effects and hereafter, it is considered that a clinical comparative study on oriental cure and auricular acupuncture therapy for headache has to be more progressed than now.