• Tribology and Lubricants
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• v.23 no.3
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• pp.95-102
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• 2007

In recently designed diesel engines, the running conditions for piston pin bearings have become very severe due to combustion pressure and temperature increase. Moreover, the lead removal from the bush material has strongly reduced the capability of the anti friction material to accept asperity contacts. In this paper, before trying to find the pressure distributions on the oil film of piston pin bearings by the unsteady two dimensional thermohydrodynamic lubrication analysis in order to do the optimum design of the bearings of piston pin, it will be investigated the tendancy of piston pin rotating motion by calculating the friction coefficient at piston pin bearings, the oil film thickness and the frictional torques induced by hydrodynamic shear stress.

• Journal of Korean Physical Therapy Science
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• v.7 no.2
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• pp.439-457
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• 2000

The causes, risk factors and sequelae of mastectomy were studied, and the physical therapy approaches on post-mastectomy was discussed in this study. It was found that the patients taken mastectomy have experienced pins and needles in muscle, weakening of muscle, pains, deterioration of motion in joint region and activities of daily living, psychiatric sequelae, and etc even after the conservertive therapies like the chemical therapy, radiotherapy, immunotherapy, and hormone therapy. However, few study on the physical therapy approaches for patients with breast cancer has been carried in Korea at present. The followings were proposed as the physical therapy approaches. 1. Shoulder joint motion approach to relax the limit of range of motion 2. Control of breathing exercise for dealing with removal of the pectorailis muscle 3. Method to reduce the edema of arms for tackling the cut of lymph node 4. Method to reduce pains, pins and needles 5. Support home exercise program after discharging from hospital, sexual life and pregnancy, and activities of daily living training method.

• Advances in Computational Design
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• v.9 no.1
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• pp.73-80
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• 2024

The aim of this paper is to remove the rigid body motion in the interior boundary value problem (BVP) of plane elasticity by solving the interior and exterior BVPs simultaneously. First, we formulate the interior and exterior BVPs simultaneously. The tractions applied on the contour in two problems are the same. After adding and subtracting the two boundary integral equations (BIEs), we will obtain a couple of BIEs. In the coupled BIEs, the properties of relevant integral operators are modified, and those integral operators are generally invertible. Finally, a unique solution for boundary displacement of interior region can be obtained.

• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.2
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• pp.335-345
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• 2021

The purpose of this study was to examine the effect of fabric movement on wrinkle recovery in a clothing care system and to propose an algorithm to improve wrinkle removal performance by adjusting fabric movements. With an increase in the reciprocating speed of the movement system, the number and amplitude of curves on the fabric also increased. This allowed the fabric to be applied to a larger tension, resulting in better wrinkle removal performance at higher speeds. However, even at high reciprocating speeds, wrinkles could not be removed effectively because of nodes at a few specific locations. Based on the results of fabric movement and wrinkle recovery, a complex movement algorithm was proposed with a mixture of various reciprocation speeds. It showed a 41%p (24%→65%) improvement of wrinkle recovery when compared with the conventional algorithm that showed simple fabric movement at 180 rpm. This was because the positions of nodes and antinodes changed continuously and the force by the reciprocating motion could be applied evenly to the fabric.

• Tribology and Lubricants
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• v.40 no.2
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• pp.67-70
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• 2024

Chemical mechanical planarization (CMP) is an essential process for ensuring high integration when manufacturing semiconductor devices. CMP mainly requires the use of polyurethane-based polishing pads as an ultraprecise process to achieve mechanical material removal and the required chemical reactions. A diamond disk performs pad conditioning to remove processing residues on the pad surface and maintain sufficient surface roughness during CMP. However, the diamond grits attached to the disk cause uneven wear of the pad, leading to the poor uniformity of material removal during CMP. This study investigates the pad wear rate profile according to the swing motion of the conditioner during swing-arm-type CMP conditioning using deep learning. During conditioning, the motion of the swing arm is independently controlled in eight zones of the same pad radius. The experiment includes six swingmotion conditions to obtain actual data on the pad wear rate profile, and deep learning learns the pad wear rate profile obtained in the experiment. The absolute average error rate between the experimental values and learning results is 0.01%. This finding confirms that the experimental results can be well represented by learning. Pad wear rate profile prediction using the learning results reveals good agreement between the predicted and experimental values.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.2
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• pp.113-130
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• 2004

Most multimedia data contain text to emphasize the meaning of the data, to present additional explanations about the situation, or to translate different languages. But, the left makes it difficult to reuse the images, and distorts not only the original images but also their meanings. Accordingly, this paper proposes a support vector machines (SVMs) and spatiotemporal restoration-based approach for automatic text detection and removal in video sequences. Given two consecutive frames, first, text regions in the current frame are detected by an SVM-based texture classifier Second, two stages are performed for the restoration of the regions occluded by the detected text regions: temporal restoration in consecutive frames and spatial restoration in the current frame. Utilizing text motion and background difference, an input video sequence is classified and a different temporal restoration scheme is applied to the sequence. Such a combination of temporal restoration and spatial restoration shows great potential for automatic detection and removal of objects of interest in various kinds of video sequences, and is applicable to many applications such as translation of captions and replacement of indirect advertisements in videos.

• Biomedical Engineering Letters
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• v.8 no.4
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• pp.365-371
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• 2018

Uninterrupted monitoring of multiple subjects is required for mass causality events, in hospital environment or for sports by medical technicians or physicians. Movement of subjects under monitoring requires such system to be wireless, sometimes demands multiple transmitters and a receiver as a base station and monitored parameter must not be corrupted by any noise before further diagnosis. A Bluetooth Piconet network is visualized, where each subject carries a Bluetooth transmitter module that acquires vital sign continuously and relays to Bluetooth enabled device where, further signal processing is done. In this paper, a wireless network is realized to capture ECG of two subjects performing different activities like cycling, jogging, staircase climbing at 100 Hz frequency using prototyped Bluetooth module. The paper demonstrates removal of baseline drift using Fast Fourier Transform and Inverse Fast Fourier Transform and removal of high frequency noise using moving average and S-Golay algorithm. Experimental results highlight the efficacy of the proposed work to monitor any vital sign parameters of multiple subjects simultaneously. The importance of removing baseline drift before high frequency noise removal is shown using experimental results. It is possible to use Bluetooth Piconet frame work to capture ECG simultaneously for more than two subjects. For the applications where there will be larger body movement, baseline drift removal is a major concern and hence along with wireless transmission issues, baseline drift removal before high frequency noise removal is necessary for further feature extraction.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.2
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• pp.24-31
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• 2011

This paper proposes spatio-temporal denoising algorithm based on nonlocal means. Though the conventional denoising algorithms based on nonlocal means have good performance in noise removal, it is difficult to implement them into the hardware system due to much computational load and the need for several frame buffers. Therefore we adopted infinite impulse response temporal noise reduction algorithm in the proposed algorithm. Proposed algorithm shows less artificial denoised result in the motionless region. In the motion region, spatial filter based on efficiently improved nonlocal means algorithm conduct noise removal with less motion blur. Experimental results including comparisons with conventional algorithms for various noise levels and test images show the proposed algorithm has a good performance in both visual and quantitative criteria.

• Journal of Yeungnam Medical Science
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• v.35 no.1
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• pp.130-134
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• 2018

Heterotopic ossification (HO) around the hip joint is not uncommon following neurological injury. Often, surgical treatment is performed in patients with restricted motion and/or refractory pain due to grade III or IV HO according to Brooker classification. The major complication that occurs as a result of surgical HO removal is perioperative bleeding due to hyper-vascularization of the lesion. Here, we report a case of preoperative embolization in a 51-year-old male patient presenting with restricted bilateral hip range of motion (ROM) due to HO following a spinal cord injury. In the right hip without preoperative arterial embolization, massive bleeding occurred during surgical removal of HO. Thus, the patient received a transfusion postoperatively due to decreased serum hemoglobin levels. For surgery of the left hip, preoperative embolization of the arteries supplying HO was performed. Surgical treatment was completed without bleeding complications, and the patient recovered without a postoperative transfusion. This case highlights that, while completing surgical removal for ROM improvements, orthopedic surgeons should consider preoperative arterial embolization in patients with hip HO.

• Tribology and Lubricants
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• v.36 no.3
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• pp.168-192
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• 2020

In recently designed diesel engines, the running conditions for piston-pin bearings have become severe because of the higher combustion pressure and increased temperature. Moreover, the metal removal from the bushing material has strongly reduced the ability of the antifriction material to accept asperity contacts. Therefore, it is necessary to find ways of reducing wear scar on the connecting-rod small-end bushing and piston-pin boss bearing related to the higher combustion pressure on the power cell of an engine. In this work, the position and level of material removal from the surfaces of the bushing and bearing under such severe operating conditions - for example, maximum power and torque conditions of a passenger car diesel engine - are estimated for several combinations of surface roughness. First, piston-pin rotating motion is investigated by calculating the friction coefficient at piston-pin bearings, the oil film thickness, and the frictional torques induced by hydrodynamic shear stress. Subsequently, the wear scarring on the surfaces of a connecting-rod small-end bushing and two piston-pin boss bearings related to piston-pin rotational motion is numerically calculated under the maximum power and torque operating conditions. This work is helpful to determine the reasonable surface roughness of the bushing and bearing for reducing wear volume occurring at the interface between a bearing and a shaft.