• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.839-847
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• 2020

The purpose of this study was to analyze the effects of ankle flexibility, gender, and Q-angle on the ankle joint injury factors during one leg drop landing. For this study, 16 males(age: 20.19±1.78 years, mass: 69.54±10.12 kg, height: 173.22±4.43 cm) and 16 females(age: 21.05±1.53 years, mass: 61.75±6.97 kg, height: 159.34±4.56 cm) in their 20's majoring in physical education using the right foot as their dominant feet were selected as subjects. First, an independent t-test of joint motion and joint moment according to the experience of ankle injury was conducted to determine the effect of physical characteristics on ankle joint injury during one leg drop landing(α = .05). Second, the variable that showed a significant difference through t-test was set as the dependent variable, and the ankle flexibility, gender difference, and Q-angle were designated as independent variables to use Multiple Linear Regression(α =. 05). As a result of this study, it was found that the group that experienced an ankle joint injury was found to use a landing strategy and technique through adduction of the ankle joint and internal rotation of the knee joint, unlike the group without an injury. It was also confirmed that this movement increases the extension moment of the ankle joint and decreases the extension moment of the hip joint. In particular, it was found that the dorsi flexion flexibility of the ankle affects the ankle and knee landing strategy, and the gender difference affects the ankle extension moment. Therefore, it was confirmed that physical characteristics factors affecting ankle joint injuries during one leg drop landing.

• Korean Journal of Cognitive Science
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• v.21 no.2
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• pp.309-338
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• 2010

In this paper, we studied the brain-computer interface (BCI). BCIs help severely disabled people to control external devices by analyzing their brain signals evoked from motor imageries. The findings in the field of neurophysiology revealed that the power of $\beta$(14-26 Hz) and $\mu$(8-12 Hz) rhythms decreases or increases in synchrony of the underlying neuronal populations in the sensorymotor cortex when people imagine the movement of their body parts. These are called Event-Related Desynchronization / Synchronization (ERD/ERS), respectively. We implemented a BCI-based mouse interface system which enabled subjects to control a computer mouse cursor into four different directions (e.g., up, down, left, and right) by analyzing brain signal patterns online. Tongue, foot, left-hand, and right-hand motor imageries were utilized to stimulate a human brain. We used a non-invasive EEG which records brain's spontaneous electrical activity over a short period of time by placing electrodes on the scalp. Because of the nature of the EEG signals, i.e., low amplitude and vulnerability to artifacts and noise, it is hard to analyze and classify brain signals measured by EEG directly. In order to overcome these obstacles, we applied statistical machine-learning techniques. We could achieve high performance in the classification of four motor imageries by employing Common Spatial Pattern (CSP) and Linear Discriminant Analysis (LDA) which transformed input EEG signals into a new coordinate system making the variances among different motor imagery signals maximized for easy classification. From the inspection of the topographies of the results, we could also confirm ERD/ERS appeared at different brain areas for different motor imageries showing the correspondence with the anatomical and neurophysiological knowledge.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.12 no.1
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• pp.149-156
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• 2001

After the fact that obsessive-compulsive symptoms or tic symptoms are common in Sydenham's chorea which is a sequale of rheumatic fever produced by group A beta-hemolytic streptococcus was reported, the association between group A beta-hemolytic streptococcus and a subgroup of obsessivecompulsive disorder(OCD) or tic disorder has been attentioned. This subgroup shared a unique clinical course, characterized by an abrupt onset of symptoms and/or dramatic exacerbations. And this subgroup was distinguished by pre-pubertal onset of symptoms, neurological abnormalities(choreiform movements and a unique pattern of motoric hyperactivity), as well as by relapsing and remitting symptom course. Acronym PANDAS(pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection) was used to denote a subgroup of OCD or tic disorder patients with these clinical characteristics. Then, there was a report suggesting that PANDAS category include some of attention-deficit/hyperactivity disorder(ADHD) and were two case reports of anorexia nervosa and body dysmorphic disorder with characteristics of PANDAS. This case is a patient who developed normally until age of 7, but after pharyngeal inflammation with high fever, he showed disturbance of cognition, social relationship, and language and communication, as well as tic symtoms and abnormal movement on face, hand, and foot. We report this case with review of literatures, because we think that this case belongs to the PANDAS category. Based on this observation, we suggest that PANDAS category include some of childhood disintegrative disorder as well as OCD, tic disorder, and ADHD.

• Journal of Korea Port Economic Association
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• v.36 no.1
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• pp.41-58
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• 2020

This study aims to investigate the technical efficiency of major container ports in the Bay of Bengal area and to study how certain factors influence the efficiency of container ports and terminals. The research is conducted on the four main container ports in the Bay of Bengal area, namely, Colombo Port in Sri Lanka, Chennai Port in India, Chittagong Port in Bangladesh, and Yangon Port in Myanmar. There are three input variables (quay length, storage area, and the number of cranes) and two output variables (throughput twenty-foot equivalent units and vessel calls) chosen for the process in this study. This paper evaluates the efficiency score of the defined variables and suggests implications for further improvement of the core competitiveness of the four selected ports. The findings indicate that Colombo Port is the most efficient on a technical scale, followed by Chennai Port, Yangon Port, and Chittagong Port. However, the slack and radial movement calculation results show that the inputs and outputs of the four ports need to be adjusted to be efficient and to reduce the amount of resources that are wasted. The results validate the adaptability of the improved data envelopment analysis algorithm in port efficiency analysis. The research findings provide an overview of the efficiencies of the selected container ports and can potentially affect the port management decisions made by policymakers, terminal operators, and carriers.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.167-177
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• 2009

The purpose of this study was to investigate effect of golf shoe design on kinematic variables during golf swing. Five professional male golfers with shoe size 270mm were recruited for the study. Swing motion was collected using 8 high speed camera motion analysis at a sampling of 180Hz. Kinematic variables were calculated by EVaRT 4.2 software. Driver swing was divided into four events; El(adress), E2(top), E3(impact) and E4(finish). Time, peak velocity, velocity of center of mass, velocity of the foot and ankle angle during Phase 1(El-E2), Phase 2(E2-E3), and Phase 3(E3-E4) were analyzed in order to investigate the relationship between golf shoe design and swing performance. The findings indicated that type C golf shoes would be beneficial for stability and control of movement during address and swing performance. Furthermore, faster speed of golf shoes, center of mass, and both feet were observed with Type C golf shoes. It is expected that golfers with Type C golf Shoes provide greater force as they control the center of mass faster and increase rotational force during impact compared to other golf shoes.

• Korean Journal of Applied Biomechanics
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• v.32 no.1
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• pp.17-23
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• 2022

Objective: The aim of this study was to investigate the effect Tiger-step walking on the movement of the lower extremities during walking. Method: Twenty healthy male adults who had no experience of musculoskeletal injuries on lower extremities in the last six months (age: 26.85 ± 3.28 yrs, height: 174.6 ± 3.72 cm, weight: 73.65 ± 7.48 kg) participated in this study. In this study, 7-segments whole-body model (pelvis, both side of thigh, shank and foot) was used and 29 reflective markers and cluster were attached to the body to identify the segments during the gait. A 3-dimensional motion analysis with 8 infrared cameras and 7 channeled EMG was performed to find the effect of tigerstep on uphill walking. To verify the tigerstep effect, a one-way ANOVA with a repeated measure was used and the statistical significance level was set at α=.05. Results: Firstly, Both Tiger-steps showed a significant increase in stance time and stride length compared with normal walking (p<.05), while both Tiger-steps shown significantly reduced cadence compared to normal walking (p<.05). Secondly, both Tiger-steps revealed significantly increased in hip and ankle joint range of motion compared with normal walking at all planes (p<.05). On the other hand, both Tiger-steps showed significantly increased knee joint range of motion compared with normal walking at the frontal and transverse planes (p<.05). Lastly, Gluteus maximus, biceps femoris, medial gastrocnemius, tibialis anterior of both tiger-step revealed significantly increased muscle activation compared with normal walking in gait cycle and stance phase (p<.05). On the other hand, in swing phase, the muscle activity of the vastus medialis, biceps femoris, tibialis anterior of both tiger-step significantly increased compared with those of normal walking (p <.05). Conclusion: As a result of this study, Tiger step revealed increased in 3d range of motion of lower extremity joints as well as the muscle activities associated with range of motion. These findings were evaluated as an increase in stride length, which is essential for efficient walking. Therefore, the finding of this study prove the effectiveness of the tiger step when walking uphill, and it is thought that it will help develop a more efficient tiger step in the future, which has not been scientifically proven.

• PNF and Movement
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• v.21 no.1
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• pp.27-35
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• 2023

Purpose: Hallux valgus (HV) is one of the most common chronic foot disorders, occurring when the first toe deviates laterally toward the other toe. HV impairs muscle strength and affects gait function (postural sway and gait speed). Thus, this study aims to investigate using the FDM system the effect of wearing braces on gait while wearing a virtual reality (VR) device. Methods: This study was conducted on 28 healthy adults with HV of 15 degrees or more. To compare differences in walking, depending on whether a toe brace can be worn, the subject walked without wearing anything, walked after wearing the VR device, and walked after wearing the VR device and the toe brace, and the FDM system was used for the gait ability measurement analysis. Results: As a result of a one-way repeated analysis of variance, the walking speed-related variables (cadence, velocity, etc.) in the HV group were higher during comfortable walking. In addition, walking while wearing a VR device and walking while wearing a VR device and a toe brace demonstrated more significant values in terms of six gait parameters (double stance phase, loading response, stage, stage, stage, and stage). The maximum pressure of the forefoot was significantly reduced when walking while wearing a VR device and a toe brace compared to comfortable walking, but in all variables, there was no statistically significant difference between walking while wearing a VR device and walking while wearing a VR device and a toe brace. Conclusion: Orthosis with a VR device during gait (OVG) and gait with a VR device (GVR) affect gait in HV patients. However, there was no significant difference between GVR and OVG. Thus, it is necessary to conduct experiments on various HV angles and increase the duration of wearing the toe brace.

• SUVANNABHUMI
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• v.2 no.1
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• pp.55-94
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• 2010

Even Faxian(法顯)'s Gaosengfaxianchuan (『高僧法顯傳』) and Iching(義淨)'s Nanhaijiguineifachuan (『南海寄歸內法傳』) are regarded as very important and useful documents to study the southeast asian buddhist culture, it is very difficult to grasp the contemporary state of those area because their descriptions are very brief and implicit. Therefore this essay aimed an in-depth reading their documents as original texts of modern understanding of those area, and tried to make a new views to approach the southeast asian buddhist culture by some more historically and concretely. At the early 5th century when Faxian(法顯) arrived, Buddhism was flourished in Sri Lanka. Because already a long time passed since the Saṇgha was schismatized into conservative and progressive at around the dominical year, he mentioned nothing about the conflict or disharmony of two orders. And the faith of Buddha tooth relic, which had been uprisen at 50 years ago from Faxian's visiting, was concretely established as a representative religion of Sri Lanka. According to his record, the carrying ritual of this Buddha tooth was performed very magnificently as similar with recent Korean Youngsan ceremony(靈山齋). In the mean time, it looks there were many sculptures of Buddha image made of precious stone of special product from Sri Lanka. The faith of Buddha-pāda(the Buddha's foot-prints) was also generalized at that time. The most famous monk of his contemporary Sir Lanka was Buddhaghosa, the author of Visuddhi-magga, but it is not sure that Faxian had met him. It can be suspected that the funeral in which Faxian participated could be belonged to him, or the Visuddhi-magga was writing at the peak during Faxian's staying. On the way to return to China, Faxian embarked an indigenous ship around Indonesia. It means there were no chinese trade ship which he can use. So the trade between china and southeast asia was advanced by south asian ships, and the chinese ships were not yet joined at that time so activity. And at least until that time, it looks there were no any remarkable buddhist movement in the southeast asian countries by where he stopped. In contrast, the southeast asian world which be seen by Iching had already experienced a lot of changes. He was impressed by the high quality buddhist culture of those area, and insisted to accept it to china. Further, he analyzed the sects of buddhism which were prevalent around the southeast asia in his contemporary time, and tried to make a good relationship with each native monks for learning from them. It looks the center of those exchanges may be Śrīvijaya of Indonesia. He also mentioned the situation of the late 7th century's Funan(扶南) in Cambodia. At that time, the buddhist Saṇgha was oppressed by newly rising Khmer(眞臘). On the other hand, he described the points of sameness and difference in detail between Indian and southeast asian buddhist culture in the field of ritual as like the practical use of garments, buddha images, and daily recited scriptures. There must be a lot of another aspects which this essay couldn't gather up or catch from these documents. Nevertheless, I hope this essay can help the researchers of this field and will wait for any advices and comments from them.

• Journal of Internet Computing and Services
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• v.17 no.4
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• pp.35-42
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• 2016

Recently many researches have been focused on the use of the markerless augmented reality system using face, foot, and hand of user's body to alleviate many disadvantages of the marker based augmented reality system. In addition, most existing augmented reality systems have been utilized rigid objects since they just desire to insert and to basic interaction with virtual object in the augmented reality system. In this paper, unlike restricted marker based augmented reality system with rigid objects that is based in display, we designed and implemented the markerless augmented reality system using deformable objects to apply various fields for interactive situations with a user. Generally, deformable objects can be implemented with mass-spring modeling and the finite element modeling. Mass-spring model can provide a real time simulation and finite element model can achieve more accurate simulation result in physical and mathematical view. In this paper, the proposed markerless augmented reality system utilize the mass-spring model using tetraheadron structure to provide real-time simulation result. To provide plausible simulated interaction result with deformable objects, the proposed method detects and tracks users hand with Kinect SDK and calculates the external force which is applied to the object on hand based on the position change of hand. Based on these force, 4th order Runge-Kutta Integration is applied to compute the next position of the deformable object. In addition, to prevent the generation of excessive external force by hand movement that can provide the natural behavior of deformable object, we set up the threshold value and applied this value when the hand movement is over this threshold. Each experimental test has been repeated 5 times and we analyzed the experimental result based on the computational cost of simulation. We believe that the proposed markerless augmented reality system with deformable objects can overcome the weakness of traditional marker based augmented reality system with rigid object that are not suitable to apply to other various fields including healthcare and education area.

• Clinical and Experimental Pediatrics
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• v.51 no.4
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• pp.391-395
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• 2008

Purpose : This study was performed evaluate optimal dose for disimpaction, efficacy and safety of PEG 4000 in children with chronic functional constipation. Methods : Eighty six children with chronic functional constipation were enrolled in this prospective study at Konkuk university hospital March, 2003 through August, 2006. Success in disimpaction with PEG 4000 was defined as meeting at least two out of three criteria; resolution of chief complaint, getting easiness of defecation with respect to frequency of bowel movement and hardness of stool based on defecation diary, and decrease in fecal impaction on simple abdominal X-ray test. Adverse effects of PEG 4000 were monitored clinically and biochemically. Results : Eighty three out of 86 children completed the study, and success rate of disimpaction was 99% (82/83). The mean dose of PEG 4000 for disimpaction was $0.93{\pm}0.28g/kg/day$ (0.4-2.0 g/kg/day, Max.: 30 g/day). Frequency of bowel movement increased ($5.02{\pm}2.71/wk$ vs. $11.25{\pm}5.43/wk$) in most children (79/83). Fecal impaction on simple abdominal X-ray test improved with statistical significance in 25 children (P=0.0007). Because of adverse effect of PEG 4000, 3 children did not complete the study; urticaria, severe diarrhea, diarrhea and abdominal pain. One 6-year-old girl who completed the study complained tingling sensation in the hand and foot without laboratory abnormality (4/86, 4.7%). Laboratory test revealed hyperosmolality without clinical symptom in 1 child, and eosinophilia in 6 children. Conclusion : The average safe and effective dose of PEG 4000 for disimpaction was $0.93{\pm}0.28g/kg/day$ (0.4-2.0 g/kg/day, Max : 30 g/day) in children with chronic functional constipation.