• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.10
• /
• pp.127-136
• /
• 2020

Purpose: This study aimed to establish a basis for application time and cold therapy interval by checking the physiological changes after applying a cold-gel and ice pack, commonly applied to cold therapy, and after passive rewarming. Method: A total of 22 healthy adults used cold-gel packs and ice packs in a Randomized control group repeated measurement study, and passive rewarming was performed for 40 minutes after 30 minutes of cold therapy. After applying to the right axilla, StO₂, SpO₂, peripheral blood flow, skin and body temperature were measured 15 times every 5 minutes. Result: In the cold-gel pack group, StO₂ decreased from 69.43% to 61.06% after 30 minutes application, and in the ice pack group, StO₂ decreased from 67.66% to 64.80% (p <001). In the cold-gel pack group, skin temperature decreased from 33.57℃ to 29.15℃ after 30 minutes application, and in the ice pack group, skin temperature decreased from 32.64℃ to 28.90℃ (p <.001). Only skin temperature recovered completely after 40 minutes of rewarming. There were insignificant differences between the cold-gel pack and ice pack. Conclusion: When applying cold therapy to the axillary, at least 40 minutes for passive rewarming is necessary after 30 minutes of application.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.5
• /
• pp.213-221
• /
• 2019

The present study aims to investigate the effects of mobile phone use on aviation students' English language learning. Considering that affective factors have impacts on English language learning, this study focuses on confidence, motivation, and anxiety in English learning. For the current study, 46 college students were recruited. The participants were divided into one experimental group (n = 24) and one control group (n = 22) at random. During 16 weeks, the experimental group joined in chat via mobile phone while the control group did not. To understand the participants' experience of mobile phone use and to compare the attitudes towards English language learning, a survey was performed. Major findings are as follows: The experimental group showed more positive attitudes towards English learning than the control group did. Specifically, the participants who engaged in chat via mobile phone became more confident and motivated to learn English but less anxious about English learning. These results provide insights into the engagement in chat via mobile phone for aviation students' English learning. This study also suggests ways how CTL at universities can support their students' English language learning using mobile phones.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.29 no.2
• /
• pp.75-82
• /
• 2006

본 연구에서 조합 최적화(Combinatorial Optimization) 이론에 바탕을 두고 있는 네스티드 분할(Nested Partition, 이하 NP) 방법을 이용한 최적화 기탄 요소선택 방법(Feature Selection)을 제안한다. 이 새로운 방법은 좋은 요소 부분집합을 찾는 휴리스틱 탐색 절차를 채용하고 있으며 데이터의 인스턴스(Instances 또는 Records)의 무작위 추출(Random Sampling)을 이용하여 이 요소선택 방법의 처리시간 관점에서의 성능을 항상 시키고자 한다. 이 새로운 접근 방법은 처리시간 향상을 위해 2단계 샘플링 방법을 채용하여 근접 최적해로의 수렴(Convergence)을 보장하는 샘플 사이즈를 결정한다. 이는 앨고리듬이 유한한 시간내에 끝이날 때 최종 요소 부분집합 해의 질(Qualtiy)에 관한 정확한 설명을 할 수 있는 이론적인 배경을 제시한다. 중요 결과를 예시하기 위해서 다양한 형태의 다섯 개의 데이터 셋을 이용하였으며 다섯 번의 반복 실험을 통한 실험 결과가 제시되며, 이 새로운 접근 방법이 기존의 단순 네스티드 분할 방법 기반의 요소선택 방법보다 처리시간 관점에서 더욱 효율적임을 보여준다.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1995.04a
• /
• pp.813-821
• /
• 1995

본 연구의 목적은 심리육체적 방법(Psychophysical method)을 이용하여 다양한 중량물운반 유형에서의 최대허용하중을 구하는 것이며 이의 타당성을 생리학적 방법(physiological method)을 이용하여 검토하는 것이다. 또한, 인체측정과 근력측정 자료를 이용하여 각 운반유형에서의 최대허용 하중을 예측하는 모형을 개발하고자 한다. 본 연구에서는 네 가지의 운반유형(Front carrying, One-hand side carrying, Two-hands side carrying 그리고 Back carrying)과 두가지의 보행 속도 (50.0 그리고 79.2 m/min)를 주요변수로 8가지의 작업에 대해 무작위로 선택하여 각 작업에 대한 최대허용 하중을 시간과 경비의 감소측면에서 폭넓게 사용되고 있는 심리육체적 방법으로 구하였다. 피실험자는 운반작업의 경력이 있는 실제 작업자군(n=7)과 그렇지 않은 학생군(n=10)으로 구분하여 건강한 남성 피실험자를 대상으로 연구를 실시하였다. 주실험전에 인체측정과 근력측정을 실시하였다. 이후에 심리육체적 방법과 생리학적 방법을 실시간(on-line)으로 실시하였다. 연구결과로 학생군과 작업자군간의 신체조건은 뚜렷한 차이를 보이지 않았으나 근력은 작업자가 우월하였다. 심리육체적 방법을 사용하여 도출된 최대허용 하중은 학생군, 작업자군 모두 운반유형의 변화에 따라 유의함을 보였다.(학생군:p=.0001 작업자군:p=.0001). 반면에 속도의 변화는 유의하지 않았다(학생군:p=.7954 작업자군:p=.9231). 또한 학생군과 작업자군 모두 Back carrying에서 가증 큰 하중을 운반하였다(학생군:8.16kg 작업자군:12.9kg). 심박수를 이용한 생리학적 연구에서는 평균 심박수가 거의 100 이하를 유지하므로써 피실험자들이 8시간 작업기준으로 보아 무리가 없는 최대허용 하중을 결정하였음을 보였다. 또한 각 운반작업에 대한 최대허용 하중을 예측하는 회귀모형을 제시하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.13 no.2
• /
• pp.57-67
• /
• 2014

In the last decade, various situations were simulated through virtual environment due to rapid improvement of computer capability and technology. Transportation engineering also has adopted the virtual environment facility in order to identify drivers behaviour under various circumstances. This study aims to evaluate driver reactions to the introduction of new ITS interventions at railway crossings (RLX) in driving simulator. Three ITS safety devices were used to figure out how drivers reacted to them. In addition, a survey was conducted to find participants' work load and acceptance of the technology. The ultimate purpose of this paper is to evaluate ITS safety devices in various aspects. Each participant made 3 runs (2 baselines, 1 ITS randomly) for approximately 20 minutes each. The participants answered that current railway crossings did not look safe prior to experiment. They responded that the use of ITS technologies were easy and the technologies were more effective on passive railway crossings.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.1
• /
• pp.257-264
• /
• 2013

The purpose of this study was to examine the weight bearing exercise effect on bone mineral density(BMD) and upper extremity function in the female stroke patients. The subject were 24 female stroke patients, randomly assigned to a weight-bearing group(n=12, WBG) and a control group(n=12, CG). The experiments were conducted for three times per week for eight weeks, radial BMD and MFT(Manual Function Test) of both groups were measured before the experiments and eight weeks after the beginning of the experiments. In conclusion, it was found that there was a significant increase of the weight-bearing group radial BMD and MFT score, The results suggest that weight bearing exercise is effective in improving BMD and upper extremity function, thus, can be utilized in stroke rehabilitation.

• Journal of the Korean Society of Physical Medicine
• /
• v.8 no.1
• /
• pp.111-116
• /
• 2013

연구목적: 본 연구는 흰쥐를 대상으로 정강뼈의 관절연골에 적용한 맥동전자장과 맥동초음파가 HSP70(Heat shock protein 70)의 발현을 통한 연골 형성에 미치는 영향을 알아보고자 실시하였다. 연구방법: 36마리의 200~250g의 Sprague-Dawley 흰쥐를 대조군, 맥동전자장 적용군, 맥동초음파 적용군으로 각 집단별로 12마리씩 무작위 배정하여 실험을 진행하였다. 맥동전자장은 27.12 MHz의 주파수, 5가우스의 강도, 450 W의 출력으로 10분간 적용하였고, 맥동초음파는 20%의 맥동비, 1MHz의 주파수, $1.5W/cm^2$의 강도로 10분간 적용하였다. 연구결과: 맥동전자장 적용군과 맥동초음파 적용군의 관절연골 조직에서 유의한 수준의 HSP70 발현량을 나타냈다. 또한 맥동전자장 적용군과 맥동초음파 적용군에서는 Akt, Erk1, CREB의 높은 활성도를 나타내었고, 맥동초음파 적용군에 비해서 맥동전자장 적용군의 더 높은 수준의 활성도를 보였다. 결론: 맥동전자장과 맥동초음파는 HSP70의 과발현을 유발하고, 이를 통해 연골형성을 증가시키는 것으로 나타나, 향후 관절연골의 손상에 대한 임상적 적용을 위한 추가적인 연구가 진행되어야 할 것으로 생각된다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.5
• /
• pp.489-495
• /
• 2014

A micro-genetic algorithm (MGA) is one of the improved forms of a genetic algorithm. It is used to reduce the number of iterations and the computing resources required by using small populations. The efficiency of MGAs has been proved through many problems, especially problems with 3-5 design variables. This study proposes an optimization algorithm based on the sequential design of experiments (SDOE) and an MGA. In a previous study, the authors used the SDOE technique to reduce trial-and-error in the conventional approximate optimization method by using the statistical design of experiments (DOE) and response surface method (RSM) systematically. The proposed algorithm has been applied to various mathematical examples and a structural problem.

• Journal of Digital Convergence
• /
• v.20 no.3
• /
• pp.53-61
• /
• 2022

The purpose of this study was to test whether or not the AI chatbot is effective in acquiring target grammar for Korean EFL college students: prepositions and articles. A quasi-experiment was conducted with 46 first-year students taking part in a required English course. They were randomly divided into two groups: the experimental and control groups (23 students for each, respectively). The experimental group was engaged in six chat sessions with a chatbot over 6 weeks. A pretest and a posttest were used to examine the effectiveness of the chatbot by comparing any changes made in error frequencies of the target grammar in participants' English compositions. The results show that after a conversation with the chatbot, the experimental group significantly reduced the mean of omission errors in both prepositions and articles. To have a great effect in other error categories, chatbot feedback needs to be improved to reduce short responses or inaccurate utterances of students and induce them to actively participate in the conversation.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.9 no.1
• /
• pp.41-50
• /
• 2014

The subjects of this study were 30 hemiplegia patients whose disease duration was over 6 months, and they were divided at random into a control group (n=15) receiving traditional rehabilitation therapy and an experimental group (n=15) receiving both traditional rehabilitation therapy and training using IT based EMG biofeedback. The program was applied for a total of 4 weeks. In order to examine the subjects' functional recovery, we measured their upper limb function using FMA and MFT, and activities of daily living using FIM before and after the training. Comparison between experimental groups in the study of upper extremity function improved after training in all tests was higher compared to the control group significantly (p<.05), but activities of daily living were not significantly different in. The results of this study were as follows. we concluded that stroke patients receving intensive IT based EMG biofeedback showed upper extremity functional recovery.