• Tribology and Lubricants
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• 제31권3호
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• pp.102-108
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• 2015

In this research, we experimentally investigated the sealing performance of elastomeric rotary lip seals for washing machines. In general, NBR is used as a material for elastomeric rotary lip seals in washing machines, but the mixing formula of the rubber material can affect the sealing performance. In this study, we manufactured rotary lip seals using three kinds of NBRs with a different mixing formula, and examined the sealing performance using an acceleration test mode. The results of an SEM investigation into the surfaces of three kinds of specimens showed a much smaller wear volume and better sealing performance for the specimens with smaller particle sizes of mixing composition than for the specimen with the larger. Repeated deformation and recovery by the shaft-to-seal eccentricity on rotation were shown to cause a phase difference in the rubber material, and we measured the recovery ratio to find the influence of this phase difference on the sealing performance. As another method for checking the phase difference, we also measured tan ä, and a lower tan ä was revealed as the recovery ratio increased for each specimen. Specimens with a higher recovery ratio (lower tan ä) were shown to have a better sealing performance. Consequently, specimens with a smaller particle size in the mixing composition had a better sealing performance because they show a higher recovery ratio.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2003년도 학술대회논문집
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• pp.175-179
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• 2003

We propose a new watermarking scheme that can be used to embed multiple bits and also resilient to JPEG compression and geometrical transforms such as scaling, rotation, and cropping based on holographic watermark that allows multiple watermark recovery without original content(cover image).

• 한국임상수의학회지
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• 제35권5호
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• pp.200-205
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• 2018

This retrospective study is designed to compare the clinical results of tibial tuberosity transposition (TTT) and anti-rotation suture (ARS) treatments for medial patellar luxation (MPL). Medical records of 133 dogs were reviewed that had undergone surgical correction of MPL between January 2013 and May 2017. MPL correction was performed on 182 stifles, with TTT and ARS being performed on 101 stifles and 81 stifles. The common dog breeds receiving surgical treatment for MPL were Maltese, Pomeranian, Chihuahua and Poodle. Mean age of dogs with MPL was 32.6 months, and their mean body weight was 4.26 kg. Seventy dogs (52.6%) were male and 63 (47.4%) were female. Of the 182 stifles with MPL, grade II, III and IV were 18.7%, 72.0% and 9.3%. Total complications after TTT and ARS were recorded in 16.8% and 29.6%. Major complications after TTT and ARS were recorded in 5.9% and 12.3%, minor complications after TTT and ARS were recorded in 10.9% and 17.3%. The risk of complication and reluxation rate after TTT were significantly lower than that for ARS (p < 0.05). However, the rate of reluxation among dogs treated by ARS (1.2%) for grade II MPL was significantly lower than that for dogs treated by ARS (8.6%) for grade III MPL (p < 0.05). The TTT group had a shorter recovery period after surgical intervention than that in the ARS group (p < 0.001). In conclusion, TTT had a significantly lower incidence of complication and a shorter recovery period than ARS. However, ARS for grade II MPL appears to be a good surgical option for reducing the rate of reluxation after surgery. These results of this study could be used to provide therapeutic guidelines for surgical MPL correction in small-breed dogs.

• Clinics in Shoulder and Elbow
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• 제17권3호
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• pp.120-126
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• 2014

Background: To compare the treatment of the proximal humerus fracture using a Polarus nail or Philos plate, we aimed to analyze the functional recovery and the factors affecting the selection between the two types of surgery. Methods: The study included 107 patients with proximal humerus fracture who underwent surgery at our institution. Of these patients, 67 underwent surgery with Polarus nails (G1) and 40 with Philos plates (G2). In G1, the cases of two- and three-part fractures were 60 and 7 cases, in G2, the cases of two-, three-, and four-part fractures were 28, 10, and 2 cases, respectively. The average age was 61 years old, and the average follow-up period was 32.5 months. We compared radiological results, the functional recovery retrospectively. Results: The radiological union time was 6.8 weeks and 8.7 weeks on average in G1 and G2 (p < 0.05). At the one-year follow-up period, these were visual analogue scale (VAS) 1.355, forward flexion (FF) 130.968, external rotation (ER) 50.161, internal rotation (IR) L2 in G1, and VAS 0.781, FF 135.806 ER 51.25, IR L1 in G2, respectively, showing no significant differences between the two groups (p > 0.05). Similar observations were made at the final follow-up. In terms of functional recovery, no significant differences were seen at the one-year or at the final follow-up period (p > 0.05). Conclusions: For the surgical treatment of proximal humeral fracture, the selection of the type of surgery is affected by the fracture pattern. However, both methods give satisfactory outcomes and do not show significant differences in the functional outcome after the surgery.

• 대한통합의학회지
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• 제8권1호
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• pp.101-111
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• 2020

Purpose : The purpose of this study was to identify the comparison of the effects of manual therapy combined with exercise on range of motion (ROM), muscle strength, and functional performance in adolescent baseball players with internal impingement syndrome of the shoulder. Methods : The subjects were 30 patients diagnosed with impingement syndrome of the shoulder. Thirty subjects are randomly assigned to each 3 different groups; Group 1. (exercise group), Group 2. (exercise+mobilization; EMOB group), Group 3. (exercise+mobilization with movement; EMWM group). The interventions were performed three times a week for 4 weeks. The main outcome measures were goniometer, Biodex dynamometer, and Korean Kerlan Jobe shoulder-elbow (K-KJOC) scores. The ROM (external and internal rotation), muscle strength (external and internal rotation: 60 °/sec., 180 °/sec.), and functional performance were compared among the groups. Results : No significant difference was observed among the groups in the range of external rotation of the shoulder before and after the intervention, but the range of internal and total rotation was significantly increased in Group 2, 3 compared to Groups 1. Muscle strength of external and internal rotation (60 °/sec., 180 °/sec.) was not significantly different among Group 1, 2, 3, and functional performance was significantly increased in Group 2, 3 compared to Group 1. However, there was no significant difference between Group 2 and Group 3 in all measurements. Conclusion : An intervention with manual therapy such as EMOB and EMWM was more effective than exercise alone for rapid recovery from shoulder injury and improvement in functional performance. However, further efforts are needed to identify effects of specific interventions with manual therapy.

• 전자공학회논문지B
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• 제31B권2호
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• pp.69-79
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• 1994

The conventional machine vision system which has uniform rectangular grid requires tremendous amount of computation for processing and analysing an image especially in 2-D image transfermations such as scaling, rotation and 3-D reconvery problem typical in robot application environment. In this study, the imaging system with nonuiformly distributed image sensors simulating human visual system, referred to as Ploar Exponential Grid(PEG), is compared with the existing conventional uniform rectangular grid system in terms of image resolution and computational complexity. By mimicking the geometric structure of the PEG sensor cell, we obtained PEG-like images using computer simulation. With the images obtained from the simulation, image resolution of the two systems are compared and some basic image processing tasks such as image scaling and rotation are implemented based on the PEG sensor system to examine its performance. Furthermore Fourier transform of PEG image is described and implemented in image analysis point of view. Also, the range and heading-angle measurement errors usually encountered in 3-D coordinates recovery with stereo camera system are claculated based on the PEG sensor system and compared with those obtained from the uniform rectangular grid system. In fact, the PEC imaging system not only reduces the computational requirements but also has scale and rotational invariance property in Fourier spectrum. Hence the PEG system has more suitable image coordinate system for image scaling, rotation, and image recognition problem. The range and heading-angle measurement errors with PEG system are less than those of uniform rectangular rectangular grid system in practical measurement range.

• 대한기계학회논문집B
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• 제27권7호
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• pp.948-955
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• 2003

Pressure coefficient in rotating discharge hole was measured to gain insight into the influence of rotation to the discharge characteristics of rotating discharge hole. Pressure measurements were done by the telemetry system that had been developed by the authors. The telemetry system measures static pressure using piezoresistive pressure sensors. Pressure coefficients in rotating discharge hole were measured in longitudinal direction and circumferential direction with various rotating speed and 3 pressure ratios. From the results, the pressure coefficient, and therefore the discharge coefficient, is known to decrease with the increase of Ro number owing to the increase of flow approaching angle to the discharge hole inlet. However, there exists critical Ro number where the decrease rate of discharge coefficient with the increase of Ro number changes abruptly; flow separation occurs from the discharge hole exit at this critical Ro number. Critical Ro number increases with the increase of length-to-diameter ratio, but the increase is small where the length-to-diameter ratio is higher than 3. The decrease rate of discharge coefficient with the increase of Ro number depends on the pressure recovery at the discharge hole, and the rate is different from each length-to-diameter ratio; it has tendency that the short discharge hole shows higher decrease rate of discharge coefficient.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.673-678
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• 2008

In crushed service areas of Metro railway lines, there are problems such as the buildup discontent, the irregular operation time and rotation of rolling stocks, caused by frequently occurred train delay. Train delay is affected by operation conditions or infrastructure capacities such as train schedule, line capacity, car rotation plan, shunting movements at origin and destination, and also by transport demand characteristics. Furthermore, a delay produce another delays and spread over the following trains. So it is not easy to build up a protection and recovery plan. In this research, we conduct experimental analysis study based on the real metro data, and as a result, present the relation between the traffic demand and the dwell time. And finally, propose future research themes for improving the operation efficiency of metro railways.

• 한국안광학회지
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• 제15권2호
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• pp.137-144
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• 2010

목적: 본 연구는 프리즘 밸러스트 디자인 원데이 토릭 소프트 콘택트렌즈의 임상적 성능을 평가하고 안경교정 상태와 시기능의 질을 비교하기 위해 실시하였다. 방법: 대상자는 구면 -2.75 D이고 -0.75 DC에서 -2.25 DC 사이의 직난시를 갖는 건강한 대학생 15명(30안)을 대상으로 프리즘 밸러스트 디자인 렌즈를 양안에서 처방하여 2주간 착용시켰다. 대상자들은 토릭렌즈의 임상성능(렌즈 안정 위치, 중심안정, 렌즈 움직임, 타이트한 정도, 렌즈 안정성, 회전 회복, 자각증상)을 평가하고 양안시 검사 값 및 대비감도를 초기 방문과 2주간 적응 후 검사하여 안경교정 상태와 비교였다. 결과, 프리즘 밸러스트 디자인의 토릭 소프트 콘택트렌즈를 2주간 착용한 후에 렌즈 방향안정, 회전 회복, 자각증상을 평가한 결과, 적응 전보다 향상되었다. 양안시 검사 값과 대비감도가 안경 착용 상태와 비교할 때 통계적으로 유의한 차이가 없는 것으로 나타났다. 결론: 프리즘 밸러스트 디자인의 토릭 소프트 콘택트렌즈를 착용한 후 임상적 기능이 증진하였다. 양안시 검사값과 대비감도가 안경교정 상태와 차이가 없는 것으로 평가되었다. 본 연구를 통해서 토릭 소프트 콘택트렌즈 착용자가 안경교정 자와 유사한 시생활을 영위할 수 있는 것으로 사료된다.

• 자원리싸이클링
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• 제11권2호
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• pp.28-35
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• 2002

충격형 분채기에 의한 폐프린트배선기판(PCBs)의 분쇄과정에서 일어나는 금속성분의 분쇄특성에 대한 연구가 수행되었다. PCBs로부터 금속성분들을 단체분리하기 위하여 -3 mm로 파쇄한 다음 충격형 분쇄기를 사용하여 분쇄하였으며 햄머의 회전속도가 금속성분의 분쇄에 미치는 영향을 관찰하였다. 동과 땜납 등과 같은 금속성분들의 입도분포 및 단체분리도를 조사하였다. 경사진동판을 사용하는 PCBs 분쇄물로부터 금속입자들의 형상분리에서 햄머의 회전속도와 입자크기가 미치는 영향을 검토하였다 61.3 m/s 햄머속도에서 동 성분은 +297$\mu$m 입자가 80% 이었지만 땜납성분은 -297$\mu$m 입자가 90%에 달했다. 형상분리법에 의한 금속입자의분리 시 햄머의 회전속도가 클수록 회수위치가 짧았으며 +297 $\mu$m 입자의 회수위치가 -297~+149$\mu$m 입자보다 짧았다. 회수위치가 짧을수록 금속입자의 구형도가 좋았으며 KI 값은 KI=1 로 증가하고, $\phi_{c}$ 값은 $\phi_{c}$ =1로 감소하였다.