• Journal of Mechanical Science and Technology
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• v.15 no.2
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• pp.239-247
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• 2001

Measured radiative heat fluxes on the furnace exit plane of a heavy duty power boiler of steam output 1650 T/h are discussed. A high-ash pulverized bituminous coal was used. Such measurements are necessary to improve heat fluxes inside a steam boiler furnace was manufactured. An extra small heat radiation sensor was placed in the water cooled head of the probe. The sensor had no direct contact with furnace gases and measured only the radiant energy. There was no exposure to convective heat transfer. With the radiometric probe, one can obtain a spherical indicatrix of radiation intensity as well as hemispherical radiative heat flux incident on any surface passing through a measuring point inside the furnace. Thus, the quantity of radiation energy, passing through the furnace exit plane, to the convective heating surfaces and the quantity of radiation energy going in the opposite direction were measured. A formula for relative radiative heat flux on the furnace exit plane has been proposed.

• Journal of Power System Engineering
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• v.14 no.4
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• pp.37-42
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• 2010

This paper deals with the sealing mechanism of the gasket component and the effects of design parameters for the exhaust manifold. The finite element model includes hot-end exhaust system and a simplified gasket model supplied by ABAQUS software. The mechanical behaviors of bead and body of a gasket are measured after several times of cyclic loads by gasket supplier. From the finite element analysis due to the cyclic thermal loads, the flange of exhaust manifold shows thermal expansion and contraction in longitudinal direction as well as convex and concave deformations with respect to the engine cylinder head. And, the contact pressures of the gasket beads suddenly changes by normal deformation of inlet flanges. Therefore, the magnitudes of contact pressures could be used to determine the sealing characteristics of the exhaust gas in the exhaust system. The distributions of contact pressures in gasket bead lines shows a good agreement with the engine test results.

• Journal of Auto-vehicle Safety Association
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• v.9 no.4
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• pp.55-60
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• 2017

This paper presents the motorcycle inspection standards of electrical system, frame & body, lights and speedometers. 187 real-world motorcycles are visually and mechanically inspected according to the developed inspection standards. The non-compliance rate of inspection standards of the lights is 23.7% and main causes are damage, tinting, painting and coloration of head-lamp, number plate lamp, front-rear position lights, stop lamp and direction indicators of motorcycles. Also, 28.4% of motorcycles are dropped from the luminous intensity inspection standard. Motorcycle electrical system cannot be visually inspected. The motorcycle inspections standards are improved reflecting 187 cases of real-world motorcycle inspection results.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2005.11a
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• pp.78-93
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• 2005

The posterior and multidirectional instability of the shoulder is a complex problem in terms of diagnosis and treatment. Increased joint volume by redundant capsular ligament has been regarded as a major pathogenesis of the posterior and multidirectional instability. Distinct from multidirectional hyperlaxity, multidirectional instability has symptoms related with increased translations in more than one direction. Recent report that shoulder symptom originates from labral lesion which was created by excessive rim-loading of the humeral head on the posteroinferior glenoid labrum during repetitive subluxation helps us to understand the pathogenesis of such instability. Painful jerk and Kim tests indicate labral lesion in the multidirectionally loose shoulder, suggesting multidirectional instability. Also, painful jerk test is a prognostic sign of failure of nonoperative treatment. The labral lesion can be an incomplete tear or a concealed lesion which often has been underestimated. Operative treatment is indicated when nonoperative treatment has failed. Arthroscopic capsulolabroplasty is a reliable procedure, which not only provides capsular balance, but also restores the labral height.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.5
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• pp.70-75
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• 2000

After the patterning and probe process of wafer have been achieved, the dicing process is necessary to separate chips from a wafer. The dicing process cuts a wafer to lengthwise and crosswise direction to make many chips by using narrow circular rotating diamond blade. But inferior goods are made under the influence of complex dicing environment such as blade, wafer, cutting water and cutting conditions. This paper describes a monitoring algorithm using feature extraction in order to find out an instant of vibration signal change when bad dicing appears. The algorithm is composed of two steps: feature extraction and decision. In the feature extraction, two features processed from vibration signal which is acquired by accelerometer attached on blade head are proposed. In the decision. a threshold method is adopted to classify the dicing process into normal and abnormal dicing. Experiment have been performed for GaAs semiconductor wafer. Based upon observation of the experimental results, the proposed scheme shown a good accuracy of classification performance by which the inferior goods decreased from 35.2% to 12.8%.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.83-86
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• 2003

This paper suggests user's interface with computer by means of detecting gaze under HMD, head mounted display, environment. System is derived as follows; firstly, calibrate a camera in HMD, which determines geometrical relationship between monitor and captured image. Second, detect the center of pupil using algorithm of the center of mass and represent a gazing position on the computer screen. If user blinks or stares at a certain position for a while, message is sent to computer. Experimental results show the center of mass is robust against glint effects, and detecting error was 7.1%. and 4.85% in vertical and horizontal direction, respectively. To adjust detailed movement of a mouse takes 0.8 sec more. The 98% of blinking is detected successfully and 94% of clicking detection is resulted.

• Journal of the Korean Society of Safety
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• v.12 no.4
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• pp.169-179
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• 1997

The dynamic response of the human brain to direct impact was studied by three-dimensional finite element modeling. The model includes a layered shell closely representing the cranial bones with the interior contents occupied by an incompressible continuum to simulate the brain. Falx and tentorium modeled with 4 node membrane element were also incorporated. The computed pressure-time histories at 4 locations within the brain element compared quite favorably with previously published experimental data from cadaver experiments. Therefore, the purpose of this study was to determine the effects of the impact direction on the dynamic response of the brain in children. A parametric study was subsequently conducted to identify the model response when the age and impact site were varied.

• Journal of Auto-vehicle Safety Association
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• v.8 no.4
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• pp.6-11
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• 2016

The objective of this study is to present the inspection standards of motorcycle lamps affecting motorcycle traffic accident in night time. The inspection standards of motorcycle lamps recommended by CITA International Motor Vehicle Inspection Committee are surveyed. Also, the domestic safety standards of motorcycle and inspection standards of passenger car are considered. The inspection standard and method with principal reasons of rejections of head-lamp, number plate lamp, front-rear position lights, stop lamp and direction indicators of motorcycles are suggested.

• KIEAE Journal
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• v.12 no.1
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• pp.29-34
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• 2012

As a series of studies about natural ventilation driven by wind in basement parking lots of apartment, the influence of opening size and surrounding buildings on ventilation rate was analyzed. Natural ventilation in underground parking lots almost rely on wind than temperature difference. To investigate natural ventilation driven by wind, wind tunnel tests by using scale model and tracer gas method were conducted. $CO_2$-gas concentration was measured, natural ventilation rates were calculated. The experimental results showed that the natural ventilation rate is more reliable to wind direction and surrounding building than opening size and distance between buildings. It was verified that surrounding buildings play a principal role in increasing air flow rate by accelerating wind speed, and growing turbulence intensity. And it showed that ventilation performance is able to be increased by oblique wind to entrance ramp than head on wind in underground parking lots with surrounding buildings.

• Journal of the Korean Institute of Rural Architecture
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• v.9 no.1
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• pp.35-42
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• 2007

This study is the research of occupation distribution about citizen members of autonomy organization in Cheongju area. Investigation of autonomy organization members acting as local readers makes it possible to understand direction for community promotion. Result of this study sums up two type occupational categories. First, in urban area independently managers is above participation ratio in public affairs appeared. On the other hand, ratio of private organization, employee, and experts are low. In rural area, it shows the participation ratio of functional representatives and farmers highly. Second, with investigation of detailed occupation, most independent contractors and such as architecture, real-estate, whole and retail sales, restaurant, nursery, and private educational institute. And small number of insurance, news paper, car sales, gas station mangers participate in autonomy organization. Private organization consist of educational organization, social welfare corporate and district head council, as well as some teachers and farmers.