• Journal of The Korean Society of Integrative Medicine
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• v.9 no.3
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• pp.135-144
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• 2021

Purpose : The purpose of this study was to investigate the effect of 2 weeks of backward walking exercise (BWE) on cervical angle and gait parameters in college students with forward head posture. Methods : Fifteen subjects participated in the experiment. All the participants had a craniovertebral angle (CVA) of 55 degrees or less. The purpose of the study was explained to all the subjects prior to participation, and volunteered to take part in the study. A camera capable of taking pictures of the lateral plane was installed at a distance of 1.5 meters from each subject. Images of forward head posture were obtained before and after performing the BWE, and the CVA and craniorotational angle (CRA) were compared pre- versus post exercise. Foot pressure and gait parameters (step length of left and right, stride length, stance of left and right, swing of left and right, step time of left and right, and stride time) were measured using a rehabilitation treadmill. The subjects performed the BWE for 2 weeks. The exercise program consisted of a 5-minute warm-up exercise, 20-minute main exercise, and 5-minute cool-down exercise. In the main exercise, the treadmill speed was set to 2.4 km/h in the first week and 3.4 km/h in the second week. A paired t test was used to compare the CVA and CRA and gait parameters before and after the exercise. Results : Comparison of the CVA and CRA before and after the BWE revealed a significant difference post exercise, with a marked improvement in forward head posture after the exercise (p<.05). Conclusion : Based on the results of this study, the BWE is considered to be an effective exercise for the forward head posture. Also, additional research is needed to shed light on the impact of the BWE on gait parameters.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.3
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• pp.420-427
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• 2020

The U.S-China disputes have attracted worldwide attention since it took place. However, the disputes between China and the US are no longer limited to the competition in traditional industries, and the competition in 5G industries is becoming more intense. This paper analyzes the reasons for US sanctions on Huawei and puts forward some Suggestions for its countermeasures. With the continuous trade exchanges between China and the United States and the acceleration of China's rise, the related industries in the United States will inevitably be impacted by the related industries in China. Despite U.S. sanctions, the fast speed and effective cost of 5G in China is further improving China's competitiveness. However, under the economic sanctions of the United States, how to survive and further develop China's 5G industry needs in-depth research.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.587-592
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• 2020

The giant information exchange enabled by the Internet of Things paradigm will likely exploit electrical lines as a ready-to-use infrastructure. The advantage of using the pre-installed infrastructure of wiring networks makes power line communication a competitive technology for broad-band communications. Therefore, there has been a growing interest towards the use of existing power line communication channels as an effective means for transmitting high speed data and Internet service. One of the main noise types affecting power line communication systems is the impulsive noise, and the focus of this work is on the impact of this impulsive noise on the performance of OFDM-QPSK systems. For the performance analysis of impulsive noise, data measured in three environments were used. Through the analysis, it is shown that OFDM-QPSK system outperforms QPSK system for most of the impulsive noise cases. Also, RS-coded OFDM-QPSK system can achieve good BER performance under 3 cases impulsive noise environment.

• Structural Engineering and Mechanics
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• v.78 no.2
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• pp.125-134
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• 2021

In this paper, the effects of Tuned Mass dampers (TMDs) on the reduction of the vertical vibrations of a real horizontally curved steel box-girder bridge due to different traffic loads are numerically investigated. The performance of TMDs to reduce the bridge vibrations can be affected by the parameters such as dynamic characteristics of TMDs, the location of TMDs, the speed and weight of vehicles. In the first part of this study, the effects of mass ratio, damping percentage, frequency ratio, and location of TMDs on the performance of TMDs to decrease vertical vibrations of different sections of bridge deck are evaluated. In the second part, the performance of TMD is investigated for different speeds and weights of traffic loads. Results show that the mass ratio of TMDs is the more effective parameter in reducing imposed vertical vibration in comparison with the damping ratio. Furthermore, it is found that TMD is very sensitive to its tuned frequency, i.e., with a little deviation from a suitable frequency, the expected performance of TMD significantly decreased. TMDs have a positive and considerable performance at certain vehicle speeds and this performance declines when the weight of traffic loads is increased. Besides, the results reveal that the highest impact of TMD on the reduction of the vertical vibrations is when free vibrations occur for the bridge deck. In that case, maximum reductions of 24% and 59% are reported in the vertical acceleration of the bridge deck for the forced and free vibration amplitudes, respectively. The maximum reduction of 13% is also obtained for the maximum displacement of the bridge deck. The results are mainly related to the resonance condition.

• Therapeutic Science for Rehabilitation
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• v.5 no.1
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• pp.77-87
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• 2016

Objective : The purpose of this study is to investigate the impact of task-oriented approach based on upper limb coordinated movement on the ability of the Korean handwriting in children with developmental coordination disorder(DCD). Methods/Design : This randomized controlled trial designed as a pre-/post- test will compare the effectiveness of task-oriented approach and process-oriented approach on handwriting performance for children with DCD aged 5 to 10. These interventions consist of 10 training sessions and 4 assessment sessions over 7weeks. Children will be measured regard to handwriting legibility, speed and pre-handwriting skills including upper limb movement skills, visual perception and visual motor coordination. Conclusion : This is the first attempt to investigate effects of a task-oriented approach in children with DCD. The significance of this study is to provide the clinical evidences to apply the task-oriented approach improves the children's handwriting performance. Furthermore it will also present a more effective intervention for handwriting by figuring out each approach's impact on the improvement of pre-handwriting skills.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.1
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• pp.94-105
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• 2013

Recently, the construction industry has been changed in such a way that the cost for bridge construction should be optimized or reduced. Therefore, bridges are required be cost-effective in terms of initial construction as well as in the maintenance during service stage. In order to reduce the cost for bridge construction, the Rahmen typed structure, in which the bridge components from superstructure to substructure are integral, has many advantages to reduce the size of structural members including girders, since the loadings from superstructure may be transferred to substructure through the connecting rebars such as stud, etc. This paper studied on the continuous Up and Down Prestressed Concrete (UD PSC) girder bridge in which the reinforced concrete pier cap is integral with the part of girders in superstructure. In previous studies, it is known that the structural behavior of continuous UD PSC girder bridge is quite different compared to the one of the bridges with conventional bearings or shoes to support the loading from girders. Nevertheless, it has hardly been studied about the structural behavior of bridge with UD PSC girder. Therefore, in this study, various dynamic behaviors of continuous UD PSC girder bridge with integral pier cap have been analyzed using numerical method. Furthermore, an equation to evaluate the impact factor is suggested for the UD PSC girder bridge which has two to three continuous spans.

• Journal of Practical Engineering Education
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• v.14 no.1
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• pp.19-25
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• 2022

This study examined the impact of direct structured approach of students who demonstrate little or no sense of basic engineer concepts in physics courses. This direct structured instruction is one of the methodologies that focuses on explicit and systematic practices in which an instructor set clear learning outcomes and clarifies the direction of the instruction. 90 participants were randomly selected and tested on the areas of problem-solving skills, reasoning, working memory, and processing speed. 20% of the participants were found to be students with basic engineering disabilities. On the other hand, in the direct structured group, 51.7% and 58.0% of the sample group (90 students) showed a 6.3% increase from the mid-term to final examinations, respectively. The subgroups with 50% or lower grades were decreased from 26.7% to 24.5%. However, five students with the lowest grade of 20% were selected as students with learning disabilities in the study and the average scores of mid-term and final exams were increased by 8.6%, which was 17.9% and 26.5%, respectively at the end of the study. As a result, it showed that direct structured approach for students with learning disabilities in the engineer concepts was effective.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.806-816
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• 2017

This study aims to offer effective policies for managing local temperatures and reducing the heat island effect by identifying elements that affect local temperatures. The three elements of natural environment, land use, and land coverage were first selected, and then control factors were applied, including season, weather, and measurement units for wind speed. In order to analyze these factors' relations to summer temperatures, an integrated model was developed, and an analysis was conducted of the urban heat island reduction effect of elements impacting local temperatures. The analysis used nationwide weather system (AWS) data from July and August 2007 and 2011-2016, land coverage data provided by the Ministry of Environment, and land use area data from local governments after rearranging them based upon their falling within a 500-meter radius ($0.79km^2$) of AWS measuring points. The study results show that the natural environment, land use, and land coverage all have a relation to changes in local temperatures. Natural elements have the greatest impact, and land use has the lowest. The results could provide basic data for establishing more effective policies to mitigate the heat island effect and strategies for enhancing the sustainability of cities.

• Journal of Korean Society of Transportation
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• v.18 no.6
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• pp.7-17
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• 2000

The Purpose of this study is to test the effectiveness of Special Transportation Management Zone system (TZ) when it is applied to Dongdaemoon commercial zone located in downtown Seoul. The study consists of two Parts ; the legal components of TZ and the case study on Dongdaemoon district. The case study includes the analysis of current traffic situation on the study zone, the design of implemention alternative for each component of TZ, the framework of impact analysis system, and the analysis results. The study finds, if 2,000 won mandatory parking fee on drivers parking in the buildings only with over 10 parking spaces and over 3.000$m^2$ in floor area, strong illegal parking enforcement, and Pro-hibition of parking passenger cars whose last digit plate number matches with the last digit of date, are implemented in the zone simultaneously, the traffic speed increases to 20.56km/h which is above the target set in the zone. In conclusion, we find that TZ2 can be an effective tool relieving traffic congestion in Seoul, and that it is necessary for introducing TZ in Seoul that relevant laws should be revised and expecting problems should be overcome.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.113-130
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• 2011

Due to the development of information and communication technology, the global influence on politics, economics, society, and culture has grown. A major example of this impact on the economic sector is the growth of e-commerce, which increases both the speed and efficiency of businesses. In light of these new developments, businesses need to shift away from the misconception that information overwhelms to embrace the enhanced competitiveness that e-commerce provides. However, concern about fraudulent transactions through e-commerce is pertinent because of the loss in both critical revenue and consumer confidence in open markets. Current solutions for fraudulent transactions include real-time monitoring and processing, payment pending, and confirmation through SMS, E-mail, and other wired means. Our research focuses on the management of Fraud Detection Systems (FDS) to safeguard online electronic payment systems. With effective implementation of our research we hope to foster an honorable online trading culture and protect consumers. Future comparative research in domestic and abroad markets would provide further insight into preventing fraudulent transactions.