• 한국통신학회논문지
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• 제26권11C호
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• pp.157-166
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• 2001

현재 시외전화시장은 이동전화의 보편화와 인터넷 이용자의 증가에 따라 매출액이 매년 감소하고 있는 추세이다. 본 논문은 국내 시외전화시장의 동향과 전망을 살펴보고 문제점을 분석하였으며, 중계망 사업의 시장활성화 전략 및 제도 개선방안을 제시하였다. 또한 IP 시대를 맞아 인터넷 전화가 시외전화 시장에 미치는 영향과 이에 대한 대처방안을 살펴보았다. 본 논문의 결과는 시외전화 시장 활성화를 위한 전략 및 If 시대에 적합한 서비스의 개발에 사용될 수 있을 것이다.

• Advances in Traditional Medicine
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• 제4권2호
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• pp.120-123
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• 2004

To test preschool children's medium- long distance stereoscopic vision normal average value, and intermittent strabismus children,s medium-long distance stereoscopic vision acuteness is the goal of this study. The software of random stereoscopic vision and graph, which is developed by Hu-Chong etc has been used, to test 414 cases normal preschool children and 19 cases intermittent exotropia childrens medium-long distance (1-5 m) stereoscopic vision (before operation and after operation). The normal average value of preschool children's medium-long distance stereoscopic vision was achieved. Intermittent exotropia children's stereoscopic vision acuteness was declined with the increase of distance. This method can provide reference as screening abnormal stereoscopic vision during scientific research and clinical work.

• 한국전문물리치료학회지
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• 제26권2호
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• pp.16-23
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• 2019

Background: High-heeled shoes can change spinal alignment and feet movement, which leads to muscle fatigue and discomfort in lumbopelvic region, legs, and feet while walking. Objects: This study aimed to identify the effects of different shoe heel heights on the walking velocity and electromyographic (EMG) activities of the lower leg muscles during short- and long-distance walking in young females. Methods: Fifteen young females were recruited in this study. The experiments were performed with the following two different shoe heel heights: 0 cm and 7 cm. All participants underwent an electromyographic procedure to measure the activities and fatigue levels of the tibialis anterior (TA), medial gastrocnemius (MG), rectus femoris (RF), and hamstring muscles with each heel height during both short- and long-distance walking. The walking velocities were measured using the short-distance (10-m walk) and long-distance (6-min walk) walking tests. Results: Significant interaction effects were found between heel height and walking distance conditions for the EMG activities and fatigue levels of TA and MG muscles, and walking velocity (p<.05). The walking velocity and activities of the TA, MG, and RF muscles appeared to be significantly different between the 0 cm and 7 cm heel heights during both short- and long-distance walking (p<.05). Significant difference in the fatigue level of the MG muscle were found between the 0 cm and 7 cm heel heights during long-distance walking. In addition, walking velocity and the fatigue level of the MG muscle at the 7 cm heel height revealed significant differences in the comparison of short- and long-distance walking (p<.05). Conclusion: These findings indicate that higher shoe heel height leads to a decrease in the walking velocity and an increase in the activity and fatigue level of the lower leg muscles, particularly during long-distance walking.

• 한국응급구조학회지
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• 제21권2호
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• pp.51-61
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• 2017

Purpose: This study measured return of spontaneous circulation (ROSC) in relation to dispatch distance in patients with out-of-hospital cardiac arrest. Methods: Of 2,347 out-of-hospital cardiac arrest patients transported by emergency medical technicians in J Province between January 1 and December 31, 2015, those under age 18, those with reserved resuscitation, and those with traumatic cardiac arrest, leaving 855 patients in the study sample. ROSC was compared between those with dispatch distance ${\leq}4km$ (short dispatch distance, 465 patients) and those with dispatch distance >4 km (long dispatch distance, 390 patients). Results: The mean was 2.17 km in the short dispatch group and 9.87 km in the long dispatch group (p=.000). Mean distance from was 6.49 km and 13.39 km in the two groups, respectively (p=.000). ROSC differed significantly between the short and long dispatch distance groups (7.1% for short dispatch distance, 3.6% for long dispatch distance, p=.025). The length of time from to cardiopulmonary resuscitation also differed significantly between the short and long dispatch distance groups (8.77 minutes and 14.63 minutes, respectively, p=.000). Conclusion: ROSC was lower in areas of long dispatch distance compared to those of short dispatch distance. We expect this was most likely due to differences in response time by age and dispatch distance to the scene of cardiac arrest. However, no significant differences were found between the groups in the factors affecting ROSC.

• 디지털융복합연구
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• 제19권12호
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• pp.165-173
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• 2021

본 연구는 장거리 LCC인 AirAsia X의 네트워크 구축에 있어서의 특성을 FSC인 말레이시아 항공과 비교 분석하여 장거리 노선 진입 및 확대에 도움을 줄 수 있는 방향을 제시하고자 하였다. 이를 위해 장거리 노선 데이터를 OAG Schedule Analyser로부터 추출하여 SNA를 이용해 2개 시기 단위로 네트워크를 분석하였다. AirAsia X의 장거리 노선 진입 이후 말레이시아 항공은 유럽 및 중동 지역뿐만 아니라 전체적으로 꾸준히 노선이 축소된 것으로 나타났다. 반면 AirAsia X는 유럽 지역 등 초장거리 대신 중국을 중심으로 동북아시아 지역의 네트워크를 더욱 늘리면서 더욱 확대된 네트워크를 구축하고 있는 것으로 분석되었다. 연구 결과 LCC 또한 7,000km 이하 장거리 노선 시장에서 성장 가능성이 있음을 확인할 수 있었다. 그리고 안정적인 성장을 하기 위해서는 수익성 높은 일부 노선에 우선 진입한 뒤 보수적인 시각에서 단계적으로 노선을 확대하는 것이 매우 필요한 것으로 판단된다. 본 연구의 결과는 LCC의 장거리 시장 진입 및 네트워크 구축전략을 수립하는 것에 도움이 될 수 있을 것이다.

• 한국운동역학회지
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• 제22권1호
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• pp.9-16
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• 2012

The purpose of this study was to compare and analyze muscle function and EMG of the trunk and the lower extremity in short and long distance athletes and in order to determine difference in peak torque per unit weight, muscle power per unit weight, endurance ratio, and %MVIC classified by muscle. For that purpose, isokinetic muscle function tests for waist, knee, and ankle joints and EMG measurements for the trunk and the lower extremity muscle with running motion were conducted for 7 short and long distance high school athletes respectively. The study over muscle function of waist, knee, and ankle joints indicates that peak torque per unit weight of short distance athletes is higher than that of long distance athletes in extension and flexion of waist joint, plantar flexion of right ankle joint, and dorsi flexion of left ankle joint. In case of the muscle power per unit weight of short distance athletes is also higher than long distance athletes in waist, knee, and ankle joints. No difference in endurance ratio of waist, knee, and ankle joints between the two groups was founded. The results of the test over EMG of the trunk and the lower extremity show that %MVIC of erector spinae, rectus femoris, vastus medialis, vastus lateralis, and tibialis anterior is higher than that of long distance athletes in support phase. The above results proved to be the same in flight phase except for %MVIC of medial gastrocnemius. In other words, %MVIC of medial gastrocnemius for short distance athletes turned out to be higher than that of long distance athletes in flight phase.

• 전자공학회논문지
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• 제51권11호
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• pp.137-145
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• 2014

본 논문에서는 지능형 영상 감시시스템을 위한 LDA기반 원거리 얼굴인식 알고리즘을 제안한다. 기존 단일 거리 얼굴영상을 학습으로 사용한 얼굴인식 알고리즘은 원거리로 갈수록 얼굴인식률이 떨어지는 문제점이 있다. 실제 거리별 얼굴영상을 사용한 방법은 얼굴인식률은 향상되지만 사용자가 직접 움직이며 학습용 거리별 얼굴영상을 취득해야하는 문제점이 있다. 그러므로 본 논문에서는 단일 거리에서 취득한 얼굴영상을 이용해 거리별 얼굴영상을 자동으로 생성하여 학습으로 사용하는 방법을 제안한다. 제안하는 방법은 기존 얼굴인식 방법과 동일한 수준의 사용자 협조에서 거리별 사용자 등록영상을 생성할 수 있는 장점이 있다. 실험결과, 제안한 알고리즘은 기존 단일 거리 학습영상 기반 알고리즘에 비해 근거리에서 평균 16.3%, 원거리에서 평균 18.0% 향상된 얼굴인식 성능을 나타냈고, 실제 거리별 얼굴영상을 사용한 방법보다 근거리에서 평균 4.3%감소했지만, 원거리에서는 동일한 얼굴인식 성능을 나타냈다.

• 한국산업융합학회 논문집
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• 제26권5호
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• pp.907-913
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• 2023

Currently, the sprinkler method is widely used as an initial suppression method in existing firefighting systems. However, this method can cause significant damage to both equipment and facilities in the hydration area. To minimize this damage, fire extinguishing monitors are being developed that can spray fire extinguishing water directly at the point of fire. These monitors are installed on the top floor of the ship, such as the Living Quarter and Ventilation System. While conventional fire extinguishing monitors focus on lightweight research with a short spray port and require a spray distance of about 40 to 45m, recent developments necessitate a longer spray port, similar to a water cannon, requiring a spray distance of about 70 to 75m. This study aims to predict the injection distance of both the existing ship-installed fire extinguisher and the long spray port fire extinguisher through hydrodynamic computer analysis, and to determine whether the injection distance has increased.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4637-4641
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• 2023

For nuclear decommissioning applications, a study was conducted to investigate the feasibility of using a laser for long-distance cutting in complex structures. Cutting tests were performed on stainless steel plates with thicknesses ranging from 10 mm to 30 mm at distances of 300 mm-700 mm from the laser head, using a laser power of 6 kW. Remarkably, the 10 mm and 20 mm thick stainless-steel plates were successfully cut at a distance of 700 mm from the head. Based on the trends observed in the results, it is anticipated that these thicknesses could also be cut at distances of approximately 1 m. Similarly, the 30 mm thick stainless-steel plate was effectively cut at a distance of 500 mm from the head. To evaluate the amount of secondary waste generated, the kerf width was measured. Due to the long-distance cutting, the average kerf width ranged from 6 mm to 16 mm. Despite the wider kerf width, long-distance cutting holds promise for efficiently handling hard-to-reach targets in nuclear decommissioning scenarios.

• 한국음향학회지
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• 제38권2호
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• pp.240-245
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• 2019

본 논문은 수중 음향센서 데이터의 원거리 케이블 전송에 관한 연구 결과이다. LVDS(Low Voltage Differential Signaling) 전송 방식으로 설계된 데이터 송수신기의 케이블에 대한 원거리 전송 신호를 측정하고 지터 특성을 분석하였다. 지터 특성을 저감하기 위하여, 원거리 전송에 따라 감쇠될 송신 신호를 역 보상하는 고역 강조(pre-emphasis) 기법을 적용하였으며, 전송 거리에 따라 송신 특성을 검증하였다.