• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.4
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• pp.32-40
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• 2005

The purpose of this study is to investigate variation of spark plug protrusion and PDA valve on the exhaust emission in a gasoline engine. Swirl is one of the important parameters that affects the characteristics of combustion. PDA valve has been developed to satisfy requirements of sufficient swirl generation for improving the combustion and reducing of emission level. Also, especially, the variation of spark plug protrusion have an important effect to the early flame propagative process. This is largely due to the high flame speed by short of flame propagation distance. So, this is forced that injection timing, spark timing and intake air motion govern the stable combustion. As a result, using two combustion chamber, without charge of engine specification and the variable spark plug location and PDA valve could be reduced exhaust gas at a part load engine conditions(1500rpm imep 3.9bar, 2000rpm imep 3.2bar, 2400rpm imep 3.9bar).

• Earthquakes and Structures
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• v.8 no.3
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• pp.681-697
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• 2015

Iran as one of the countries located on the Alpine-Himalayan seismic belt has recently experienced a few number of catastrophic earthquakes. A well-known index of how buildings are affected by earthquakes is through assessment of probable Peak Ground Acceleration (PGA) and structures' response spectra. In this research, active faults around Kerman and Birjand, two major cities in eastern parts of Iran, have been considered. Seismic catalogues are gathered to categorize effects of surrounding faults on seismicity of the region. These catalogues were further refined with respect to time and space based on Knopoff-Gardner algorithm in order to increase statistical independency of events. Probabilistic Seismic Hazard Analysis (PSHA) has been estimated for each of cities regarding 50, 100, 200 and 500 years of structures' effective life-span. These results subsequently have been compared with Deterministic Seismic Hazard Analysis (DSHA). It has been observed that DSHA not necessarily suggests upper bound of PSHA results. Furthermore, based on spectral Ground Motion Prediction Equations (GMPEs), Uniform Hazard Spectra (UHS) and spectral acceleration were provided for 2% and 10% levels of probability of exceedance. The results show that increasing source-to-site distance leads to spectral acceleration reduction regarding each fault. In addition, the spectral acceleration rate of variation would increase if the source-to-site distance decreases.

• Journal of Biosystems Engineering
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• v.30 no.5 s.112
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• pp.293-298
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• 2005

The purpose of this study was the development of a multi-joint robot manipulator for milking robot system. The multi-joint robot manipulator was controlled by 5 drivers with driver controller through the position information obtained from the image processing system. The robot manipulator to automatically attach each teat cup to the teats of a milking cow was developed and it's motion was accurately measured with error rate. Results were as follows. 1. Maximum errors in position accuracy were 4mm along X-axis, 4.5mm along Y-axis and 0.9mm along Z-axis. Absolute distance errors were maximum 4.8mm, minimum 2.7mm, and average 3.6mm. 2. Errors of repeatability were maximum 3.0mm along X-axis, 3.0mm along Y-axis, and 0.5mm along Z-axis. Distance error values were maximum 3.2mm, minimum 2.2mm, and average 2.5mm. It is envisaged that multi-joint robot manipulator can be applicate to milking robot system being developed in consideration of the experiment results.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.2
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• pp.132-135
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• 2009

The video similarity measure is very important factor to index and to retrieve for video data. In this paper, we propose the luminance projection model to measure the video similarity efficiently. Most algorithms for video indexing have been commonly used histograms, edges, or motion features, whereas in this paper, the proposed algorithm is employed an efficient measure using the luminance projection. To index effectively the video sequences and to decrease the computational complexity, we calculate video similarity using the key frames extracted by the cumulative measure, and compare the set of key frames using the modified Hausdorff distance. Experimental results show that the proposed luminance projection model yields the remarkable accuracy and performance than the conventional algorithm.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.11
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• pp.840-846
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• 2002

The vibrational system of this study is consisted of a cantilever pipe conveying fluid, the moving masses upon it and an attached tip mass. The equation of motion is derived by using Lagrange equation. The influences of the velocity and the number of moving masses and the velocities of fluid flow in the pipe have been studied on the natural frequency of a cantilever pipe by numerical method. As the size and number of a moving mass increases, the natural frequency of cantilever pipe conveying fluid is decreased. When the first a moving mass Is located at the end of cantilever pipe, the increasing of the distance of moving masses make the natural frequency increase at first and third mode, but the frequency of second mode is decreased. The variation of natural frequency of the system is decreased due to increase of the number of a moving mass. The number and distance of moving masses effect more on the frequency of higher mode of vibration.

• Journal of Astronomy and Space Sciences
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• v.35 no.4
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• pp.263-277
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• 2018

This paper presents a vision-based relative pose estimation algorithm and its validation through both numerical and hardware experiments. The algorithm and the hardware system were simultaneously designed considering actual experimental conditions. Two estimation techniques were utilized to estimate relative pose; one was a nonlinear least square method for initial estimation, and the other was an extended Kalman Filter for subsequent on-line estimation. A measurement model of the vision sensor and equations of motion including nonlinear perturbations were utilized in the estimation process. Numerical simulations were performed and analyzed for both the autonomous docking and formation flying scenarios. A configuration of LED-based beacons was designed to avoid measurement singularity, and its structural information was implemented in the estimation algorithm. The proposed algorithm was verified again in the experimental environment by using the Autonomous Spacecraft Test Environment for Rendezvous In proXimity (ASTERIX) facility. Additionally, a laser distance meter was added to the estimation algorithm to improve the relative position estimation accuracy. Throughout this study, the performance required for autonomous docking could be presented by confirming the change in estimation accuracy with respect to the level of measurement error. In addition, hardware experiments confirmed the effectiveness of the suggested algorithm and its applicability to actual tasks in the real world.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.2
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• pp.153-163
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• 2019

Purpose : This study was to identify the effects of Mobilization with Movement combined with exercise (EMWM) on acromio-humeral distance (AHD), range of motion (ROM), pain intensity, and functional performance in patients with impingement syndrome of the shoulder. Methods : The subjects were 40 patients diagnosed with impingement syndrome of the shoulder. Twenty subjects are randomly assigned to each 2 different groups; Group 1. (exercise group), Group 2. (EMWM group). Three weekly interventions were given for 4 weeks. The main outcome measures were ultrasound, goniometer, visual analogue scale (VAS), and Korean Constant shoulder score (K-CSS). The ultrasound (AHD), ROM (flexion, abduction), pain intensity (for shoulder flexion) and functional performance (K-CSS) were compared between the groups. Results : The AHD was significantly increased in Group 2 compared to Groups 1. No significant difference was observed between the groups in the range of abduction of the shoulder, but the range of flexion was significantly increased in Group 2 compared to Groups 1. Pain intensity was significantly lower in Group 2 than in Group 1, and functional performance was significantly increased in Group 2 compared to Group 1. Conclusion : An intervention that combined mobilization with movement with exercise was more effective than exercise alone for rapid recovery from shoulder injury and improvement in functional performance.

• Korean Journal of Applied Biomechanics
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• v.32 no.4
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• pp.147-152
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• 2022

Objective: The purpose of this study was to analyze the effects of club head and golf ball kinematics and body alignment according to the swing plane during golf driver swing. Method: Sixteen college golfers participated in this study. Kinematic data of the club head and golf ball were collected using golf swing analysis system (Trackman Ver. 3e). The body alignment variables were collected using 8 motion capture system. An Independent samples t-test was used for comparison between the Out-to-In group and In-to-Out group, and the statistical significance level was set at .05. Results: For the club head related variables, club path and club face angle showed higher values in Out-to-In swing plane than In-to-Out swing plane. For the kinematic variables of the golf ball, the total distance showed a higher value in the In-to-Out swing plane than that of the Out-to-In swing plane. For the body alignment, the In-to-Out swing plane showed higher values than the Out-to-In swing plane for the pelvis rotation angle and trunk rotation angle. Conclusion: This study suggest that it would be more effective to use the In-to-Out swing plane for increasing the total distance during the golf driver swing.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.571-583
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• 2022

On 7 August 2020, a large-scale catastrophic landslide was triggered by extreme rainfall at Osan village, Gokseong County, South Jeolla Province, South Korea. The initiation mechanism of the Gokseong landslide was different from those typical landslides that occurred in South Korea. Despite the relatively low elevation and slope degree, the landslide had a long runout distance of about 640 m over a total vertical distance of 90 m. A detailed field investigation and chemical analysis were conducted to understand the possible mechanisms for the high-speed and long-runout behavior of the landslide. The terrain controlled the motion behavior of the landslide and the seepage was observed at the whole landslide body. The clay-rich soils covered on granite bedrock of the landslide deposition area from the rice paddy field to the landslide crown. The results of this study may provide basic data for further research on the mechanisms for landslide initiation and propagation.

• Journal of the Korean earth science society
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• v.37 no.7
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• pp.398-407
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• 2016

We cooperated with four domestic educational astronomical observatories to construct a baseline and perform simultaneous observations to determine the geocentric parallax, distance, and motion of 1036 Ganymed, an Amor asteroid near the Earth. Observations were made on the day when simultaneous observations were possible from September to November 2011. Measured distances of 1036 Ganymed were 0.394 AU on Sept. 26, 0.365 AU on Oct. 11, and 0.340 AU on Oct. 25, respectively, which were within the error range as compared with the measured distances proposed by the US Jet Propulsion Laboratory. The 1036 Ganymed showed a tilting motion during the observation period, and the tangential angular velocities were measured at $0.037-0.052^{{\prime {\prime}}\;sec^{-1}$. Through this study, it was shown that the simultaneous observations among educational astronomical observations can obtain distance measurements with an error range of about 5% for asteroids near 0.4 AU. And it expected to be used as a research & education program emphasizing collaborative observation activities based on a network between observatories.