• Journal of the Korean GEO-environmental Society
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• v.23 no.9
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• pp.25-31
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• 2022

Attaching shelf to retaining structure leads to a decrease in the total lateral earth pressure. This decrease enables the retaining structures to become more stable, to have small displacement, and to exhibit lower bending moments, the relief shelves effects are analyzed using FEM in order to understand how they stabilize cantilever wall in this study. Several models are varied by changing location and width of shelves to realize earth pressure and displacements of retaining wall. The displacement is getting smaller because earth pressure acting on shelf increases as shelves locations are lower and width is longer. The ground settlement variation effects caused by relief shelves are studied also. The ground settlement increases abruptly where shelf location is between of 0.5H and 0.625H, and settlement decreases suddenly where shelf width is between b/h=0.375 and b/h=0.500. The shelf significantly reduces earth pressure and movement of the wall. This decrease in the lateral pressure increases the retaining structure stability.

• Journal of Drive and Control
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• v.13 no.4
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• pp.7-13
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• 2016

This paper presents the meter-out and meter-in speed control characteristics of a pneumatic cylinder with relief valve type cushion device. The piston displacement and velocity are measured to investigate high speed driving performance with variation of the pressure setting in relief valve, air supply pressure, load mass, the supply and exhaust flow rate from the cylinder. Also, the internal pressures and temperatures driving pressure and cushion chamber are measured. The piston displacements and velocities of meter-out and meter-in control are compared experimentally determined data. A comparison experimental data meter-out and meter-in control show that a relief valve type cushion device is suitable for high speed pneumatic cylinders. The desired response characteristics of piston displacement and velocity are satisfactory adjust the pressure setting of a relief valve with varying system parameters such as air supply pressure, load mass and controlled flow rate.

• Journal of Oral Medicine and Pain
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• v.25 no.1
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• pp.73-85
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• 2000

The purposes of the study were (1) to see if there are various types of disc configuration in normal temporomandibular joint and, if so, (2) to examine whether a specific type of disc configuration is susceptible to disc displacement, and (3) to see if a specific type of disc configuration and position is related to early relief of clinical symptoms from the anterior disc displacement without reduction to conservative treatment. From the magnetic resonance (MR) images taken for the patients with symptoms of temporomandibular disorders, 235 images as normal joint group, 255 images as anterior disc displacement with reduction group, and 249 images as anterior disc displacement without reduction group were selected, After the TMJ image was scanned and processed with Photoshop program, the disc configuration was determined, The incidence of various types of disc configuration was analyzed according to age, sex, diagnostic group, and the promptness of symptom relief. The disc position was also examined in relation to the promptness of symptom relief. The results were as follows : 1. In the normal joint group, biconcave type appeared most frequently and reversed, biplanar type in order, Posterior band enlarged and folded type didn't appear at all. On the other hand, in the anterior disc displacement without reduction group, folded type appeared most frequently and also posterior band enlarged type were found often. 2. There were statistically significant differences between sex and configuration of disc in the normal joint group and no statistically significant differences in the anterior disc displacement with reduction group and anterior disc displacement without reduction group, 3. There were no statistically significant differences between age and configuration of disc in the normal, anterior disc displacement with reduction group and anterior disc displacement without reduction group. 4. In anterior disc displacement without reduction group, rapid response was observed in biconcave and reversed type and delayed response was observed in folded type.

• Fire Science and Engineering
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• v.30 no.2
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• pp.106-113
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• 2016

Ultra-high pressure positive displacement pump can discharge high pressure water with mass volume, which depends on periodic changes in volume that made by rotation motor. Its high efficiency of discharge is one of the most strong point of positive displacement pump. Due to its simple system structure, it can be miniaturized and lightened. Positive displacement pump can discharge high pressure with stable flow rate, irrespective of pressure fluctuate. This is the reason that positive displacement pump was used instead of centrifugal pump. In this study, shutoff operating system was developed for positive displacement pump to secure safety of high pressure operate. This shutoff system contains controller system, electronic clutch, and relief valve, and each part is mutual supplementation. Speed test was carried out in order to check operation of controller program and electronic clutch and fluid flow, venting experiment of the relief valve. It was confirmed that segment system of ultra-high pressure positive displacement pump is operated.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.273-276
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• 2007

In this study, we generated DSM(Digital Surface Model)s and orthophotos with both LIDAR data and scanned aerial photos and compared them with those generated from only the scanned photos. We checked the relief displacements of buildings appearing in the generated orthophotos, where the displacement should not be exist in a true-orthophoto. The RMSE of the relief displacement in the orthophoto generated using a LIDAR DSM is 3 m while the RMSE in the orthophotos from a DSM based on the image matching is 6.1 m. It was revealed that the orthophoto from a LIDAR DSM are closer to a true-orthophoto. But the results in the accuracy test and similarity evaluation of the generated orthophotos were contrary to former results because the roof texture of buildings were expanded to occlusion areas around the buildings. With the central area of the photo, we can generate sufficiently accurate true-orthophotos using a LIDAR DSM.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.103-106
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• 2007

Recently, production and application of ortho image using high resolution image are increasing by acquired high quality data from development of photogrammetry and IT technology. Generally, An ortho image has some problems that cannot remove completely to relief displacement about cultural feature like building and overpass because of performance rectification using DEM. Therefore, in this study, I generated DSM each of four experiment cases for production of true ortho image which is removed relief displacement of building using digital photogrammetry technique and LiDAR data, presented the plan of DSM production that is appropriate to production true ortho image by analyzing an accuracy after manufacture an ortho image each of DSM.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.11
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• pp.935-940
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• 2002

For robot navigation and visual reconstruction, structure from motion (SFM) is an active issue in computer vision community and its properties arc also becoming well understood. In this paper, when using stereo image sequence and direct method as a tool for SFM, we present a new method for overcoming bas-relief ambiguity. We first show that the direct methods, based on optical flow constraint equation, are also intrinsically exposed to such ambiguity although they introduce robust methods. Therefore, regarding the motion and depth estimation by the robust and direct method as approximated ones. we suggest a method that refines both stereo displacement and motion displacement with sub-pixel accuracy, which is the central process f3r improving its ambiguity. Experiments with real image sequences have been executed and we show that the proposed algorithm has improved the estimation accuracy.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.57-59
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• 2003

Digital surface model generation from IKONOS stereo imagery is a new challenge in photogrammetric community, especially when the satellite company does not provide the raw data as well as their ancillary ephemeris data. In this paper we utilized an estimated relief displacement azimuth and the nominal collection elevation data included in the metadata file to correct the relief displacement of GCPs, together with a linear transformation for geometric modeling of IKONOS imagery. Space intersection is performed by the trigonometric intersection assuming a parallel projection of IKONOS imagery due to its small FOV and frame size. In the experiment, less than 2-meters of RMSE in orbit modeling is achieved denoting the potential positioning accuracy of the IKONOS stereo imagery.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.4
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• pp.148-153
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• 2008

Although manual traction, one of pain therapies, was applied in clinic to relief pain, the study was rare on the manual force and displacement of ligaments at knee joint during manual traction. The aim of this study is to quantify not only manual force at knee joint but also elongated displacement of joint ligament by C-arm scanning and motion analysis. Twenty-one healthy subjects were tested with manual traction from grade I to grade III under neutral position by a physical therapist. We calculated traction force using joint farces of both hands and elongated displacement of joint ligament were measured. The results showed that traction forces by C-arm scanning analysis were averagely 1.67-fold greater than those by motion analysis, but elongated displacements were instead averagely 2.36-fold smaller than motion analysis. Finally, we could estimate relationship between traction force and elongated displacement at knee joint by two methods.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.40 no.4
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• pp.155-159
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• 2014

Objectives: The purpose of this article is to evaluate factors influencing prognosis of arthrocentesis in patients with temporomandibular joint (TMJ) disorder. Materials and Methods: The subjects included 145 patients treated with arthrocentesis at the Dental Center of Ajou University Hospital from 2011 to 2013 for the purpose of recovering mouth opening limitation (MOL) and pain relief. Prognosis of arthrocentesis was evaluated 1 month after the operation. Improvement on MOL was defined as an increase from below 30 mm (MOL ${\leq}30mm$) to above 40 mm (MOL ${\geq}40mm$), and pain relief was defined as when a group with TMJ pain with a visual analog scale (VAS) score of 4 or more (VAS ${\geq}4$) decreased to a score of 3 or more. The success of arthrocentesis was determined when either mouth opening improved or pain relief was fulfilled. To determine the factors influencing the success of arthrocentesis, the patients were classified by age, gender, diagnosis group (the anterior disc displacement without reduction group, the anterior disc displacement with reduction group, or other TMJ disorders group), time of onset and oral habits (clenching, bruxism) to investigate the correlations between these factors and prognosis. Results: One hundred twenty out of 145 patients who underwent arthrocentesis (83.4%) were found to be successful. Among the influencing factors mentioned above, age, diagnosis and time of onset had no statistically significant correlation with the success of arthrocentesis. However, a group of patients in their fifties showed a lower success rate (ANOVA P=0.053) and the success rate of the group with oral habits was 71% (Pearson's chi-square test P=0.035). Conclusion: From this study, we find that factors influencing the success of arthrocentesis include age and oral habits. We also conclude that arthrocentesis is effective in treating mouth opening symptoms and for pain relief.