• Journal of the Korean Society of Physical Medicine
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• v.5 no.3
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• pp.375-383
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• 2010

Purpose : The purpose of this study was to investigate a modified maneuver for quadriceps setting exercise for patients with knee osteoarthritis. Methods : The patients were randomly divided into a modified maneuver for quadriceps setting exercise group(MQG) and conventional quadriceps setting exercise group(CQG). Total of 28 patients received a modality with training for 1 hour, three times a week for 12 weeks. Results : Each group showed significant reductions in the WOMAC(Western Ontario McMaster Universities Osteoarthritis) Index, mobility, and muscle strength after 12 weeks. In pain, physical function, and hamstring muscle strength, there was a statistically significant difference between groups. Conclusion : According to the results, MQG experienced less pain, physical function, and increased more hamstring muscle strength than NQG.

• Journal of Korean Physical Therapy Science
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• v.19 no.1
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• pp.1-7
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• 2012

Purpose : This study aims to examine effects of trunk strengthening exercise in three rigid cerebral palsy adolescents aged between 11 and 13 on their spinal segments and gait. Methods : 2A trunk strengthening program for proprioceptive neuromuscular facilitation was made focusing on improvement in their school life and mental and social activities during their school years, and then trunk strengthening exercise was applied to the three subjects for 30 minutes five times per week for four weeks. With the subjects in a static state, each group's gait analysis was made and maximum anterior flexion, maximum extension, maximum left and right lateral flexion, and cross rotation of the trunk were measured using Sonosens (Germany) prior to and after the intervention. Results : Assessment of spinal segment mobility with the subjects in a static state showed that the trunk muscle strengthening exercise increased their maximum joint movement angles from the right side to the center and rotational abilities of the cervical and lumbar spines. Gait analysis indicated increased movements in the thoracic and lumbar spines and relatively decreased anterior-posterior movement of the cervical spine. Conclusion : Trunk strengthening program is effective in enhancing spinal segment mobility and balance ability of cerebral palsy adolescents and considered able to be used together with diverse treatment interventions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.7
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• pp.637-644
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• 2009

We have analyzed the biomechanical characteristics of cervical spine after total disc replacement using finite element analysis. A finite element model of C2-C7 spinal motion segment was developed and validated by other experimental studies. Two types of artificial discs, semi-constraint and un-constraint, were inserted at C6-C7 segments. Inferior plane of C7 vertebra was fixed and 1Nm of moment were applied on superior plane of C2 vertebra with 50N of compressive load along follower load direction. Mobility of the cervical spine in which each artificial disc inserted was higher than that of intact one in all loading conditions. Also, high mobility at the surgical level after total disc replacement could lead higher facet joint force and ligaments axial stresses. The results of present study could be used to evaluate surgical option and validate the biomechanical characteristics of the implant in total disc replacement in cervical spine.

• Journal of Aerospace System Engineering
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• v.15 no.4
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• pp.64-74
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• 2021

Unmanned Aircraft Systems (UAS) are rapidly emerging not only as a key military power, such as surveillance and reconnaissance for military purposes but also as a new air transportation means in the form of Urban Air Mobility (UAM). Currently, airworthiness certification is carried out focused on the verification of technical standards for flight safety suitability of aircraft design in accordance with the Military Aircraft Flight Safety Certification Act and does not employ the model for operational risk assessment for mission areas and airspace. In this study, in order to evaluate the risk of the mission area from the perspective of the UAS operator, a risk assessment simulation has been conducted by applying the Specific Operations Risk Assessment (SORA) model to the operating environment of the Korean military UAS. Also, the validity of the SORA model has been verified through the analysis of simulation results, and a new application plan for airworthiness certification of the military unmanned aerial system has been presented.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.2
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• pp.95-111
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• 2021

As the population decreases in an aging society, the average age of drivers increases. Accordingly, the elderly at high risk of being in an accident need autonomous-driving vehicles. In order to secure driving safety on the road, several technologies to respond to various obstacles are required in those vehicles. Among them, technology is required to recognize static obstacles, such as poor road conditions, as well as dynamic obstacles, such as vehicles, bicycles, and people, that may be encountered while driving. In this study, we propose a deep neural network algorithm capable of simultaneously detecting these two types of obstacle. For this algorithm, we used 1,418 road images and produced annotation data that marks seven categories of dynamic obstacles and labels images to indicate road damage. As a result of training, dynamic obstacles were detected with an average accuracy of 46.22%, and road surface damage was detected with a mean intersection over union of 74.71%. In addition, the average elapsed time required to process a single image is 89ms, and this algorithm is suitable for personal mobility vehicles that are slower than ordinary vehicles. In the future, it is expected that driving safety with personal mobility vehicles will be improved by utilizing technology that detects road obstacles.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.2
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• pp.308-318
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• 2009

The purpose of this study was to develop the functionally improved winter work clothing for the Korean railroad workers. Based on the questionnaires, the sample clothing for the Korean railroad workers was produced. The design, materials, and patterns were modified to increase mobility and comfort of workers. Water-repellent treatment was added to the material in order to decrease the dirt and stains while working. Also the reflective strips were added to chest and back of the upper garment in order to increase visibility and safety of the workers. In terms of the design and pattern underarm of the sleeve and side panel of the bodice were put in together and action pleats at the back were inserted in order to decrease the pullback of the armpit and scapular area and increase mobility of the arm movement. Also the patterns of the elbows areas were modified to increase mobility of joint. The prototype was evaluated an objective assessment and subjective assessment to compare to the existing working uniform. Assessment group was consisted of 5 subject groups and 11 expert groups and evaluated external appearance and adaptability to the movements. According to the results, the prototype was evaluated better than the existing working uniform in appearance and adaptability except height of collar. A field test was conducted to compare the prototype and the existing working uniform. The field tests were performed by 6 workers in the Korean railroad. According to the results, the prototype was improved in terms of adaptability and comfort.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.2
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• pp.47-52
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• 2023

Mobile Edge Computing(MEC) is considered as a promising technology to effectively support the explosively increasing traffic demands. It can provide low-latency services and reduce network traffic by caching contents at the edge of networks such as Base Station(BS). Although users may associate with the nearest BSs, it is more beneficial to associate users to the BS where the requested content is cached to reduce content download latency. Therefore, in this paper, we propose a mobility-aware joint caching and user association algorithm to imporve the cache hit ratio. In particular, the proposed algorithm performs caching and user association based on sojourn time and content preferences. Simulation results show that the proposed scheme improves the performance in terms of cache hit ratio and latency as compared with existing schemes.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.2
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• pp.180-185
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• 1995

TMJ ankylosis is classified with true and false type. A true ankylosis is defined as any condition that produces fibrous or bony adhesions between the articular surfaces of the temporomandibular joint. The main causes of true ankylosis are trauma or infection. A false ankylosis results from pathologic conditions outside the joint that limit mobility of the mandible such as myogenic disorders, coronoid impingement or rare direct bony fusion between maxilla and mandible. The treatment of choice of TMJ ankylosis is surgical intervention. We experienced the male patient with complete mouth opening limitation since 45 years before. This patient has true TMJ ankylosis and rare bony synostosis between maxilla and mandible in the right posterior region. We performed surgical intervention and had a favorable result.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.2
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• pp.121-129
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• 2000

The robotic automation in NonDestructive Testing(NDT) is a promising field of research and it helps to expand the applications of NDT enormously. Especially, in the case of pipelines which are widely used in various industrial facilities, it is required to secure adequate ways of inspection in the usual maintenance activitites. In this paper, we present a robot system for inpipe inspection of underground urban gas pipelines. The robot is configured as an articulated structure like a snake with a tether cable. Two active driving vehicles are located in front and rear of the system, respectively and passive modules such as a NonDestructive Testing module and a control module are chained between the active vehicles. The proposed system has outstanding mobility by employing a new steering mechanism called Double Active Universal Joint, which makes it possible to cope with complicated configurations of underground pipelines. Characteristic features of the system are described and the construction of the system is briefly outlined.

• The Journal of Korea Robotics Society
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• v.10 no.2
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• pp.119-132
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• 2015

Two novel parallel mechanisms (PMs) employing two or three PaPaRR subchains are suggested. Each of those two PMs has translational 3-DOF motion and employs only revolute joints such that they could be adequate for haptic devices requiring minimal frictions. The position analyses of those two PMs are conducted. The mobility analysis, the kinematic modeling, and singularity analysis of each of two PMs are performed employing the screw theory. Then through optimal kinematic design, each of two PMs has excellent kinematic characteristics as well as useful workspace size adequate for haptic applications. In particular, by applying an additional redundantly actuated joint to the 2-PaPaRR type PM which has a closed-form position solution, it is shown that all of its parallel singularities within reachable workspace are completely removed and that its kinematic characteristics are improved.