• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11C
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• pp.157-166
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• 2001

The sales of long-distance telephone market decreased every year according to increased mobile phone and Internet users. This paper researches trend of domestic long-distance telephone market, and suggests marketing and improving plan for long-distance telephone network providers. And we investigate the effects of the Internet phone on IP era for long-distance telephone service market. The results of this paper can be used for strategies for improving long-distance telephone market and service development on IP era.

• Advances in Traditional Medicine
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• v.4 no.2
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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.

• Physical Therapy Korea
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• v.26 no.2
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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.

• The Korean Journal of Emergency Medical Services
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• v.21 no.2
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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.

• Journal of Digital Convergence
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• v.19 no.12
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• pp.165-173
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• 2021

The purpose of this study was to provide directions to help enter and expand long-distance routes by analyzing the characteristics of AirAsia X's network construction with Malaysia Airlines. To this end, long-distance route data was extracted from the OAG Schedule Analyzer and the network was analyzed on a two-period basis using SNA. Since AirAsia X's entry into long-range routes, Malaysia Airlines has steadily reduced its routes across the entire region. On the other hand, it is analyzed that AirAsia X is building an expanded network by increasing its network in Northeast Asia instead of ultra-long range routes. Studies have shown that LCCs also have potential growth in the long-distance route market of less than 7,000 km. The results of this study may help LCC establish a long-distance market entry and network deployment strategy.

• Korean Journal of Applied Biomechanics
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• v.22 no.1
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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.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.11
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• pp.137-145
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• 2014

This paper suggests an LDA-based long distance face recognition algorithm for intelligent surveillance system. The existing face recognition algorithm using single distance face image as training images caused a problem that face recognition rate is decreased with increasing distance. The face recognition algorithm using face images by actual distance as training images showed good performance. However, this also causes user inconvenience as it requires the user to move one to five meters in person to acquire face images for initial user registration. In this paper, proposed method is used for training images by using single distance face image to automatically create face images by various distances. The test result showed that the proposed face recognition technique generated better performance by average 16.3% in short distance and 18.0% in long distance than the technique using the existing single distance face image as training. When it was compared with the technique that used face images by distance as training, the performance fell 4.3% on average at a close distance and remained the same at a long distance.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.5
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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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• v.55 no.12
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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.

• The Journal of the Acoustical Society of Korea
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• v.38 no.2
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• pp.240-245
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• 2019

This paper is a study result on long distance transmission of underwater acoustic sensor data over cable. The data transceiver is designed using the LVDS (Low Voltage Differential Signaling) transmission scheme, and the jitter characteristics are analyzed by measuring the long distance transmission signal through the cable. In order to reduce the jitter, a pre-emphasis technique is applied to compensate the transmitting signal to be attenuated by long distance transmission, and the transmission characteristics were verified according to the distance.