• Computers and Concrete
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• 제28권6호
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• pp.533-547
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• 2021

Calculating the shear capacity of slender reinforced concrete beams without shear reinforcement was the subject of numerous studies, where the eternal problem of developing a single relationship that will be able to predict the expected shear capacity is still present. Using experimental results to extrapolate formulae was so far the main approach for solving this problem, whereas in the last two decades different research studies attempted to use artificial intelligence algorithms and available data sets of experimentally tested beams to develop new models that would demonstrate improved prediction capabilities. Given the limited number of available experimental databases, these studies were numerically restrained, unable to holistically address this problem. In this manuscript, a new approach is proposed where a numerically generated database is used to train machine-learning algorithms and develop an improved model for predicting the shear capacity of slender concrete beams reinforced only with longitudinal rebars. Finally, the proposed predictive model was validated through the use of an available ACI database that was developed by using experimental results on physical reinforced concrete beam specimens without shear and compressive reinforcement. For the first time, a numerically generated database was used to train a model for computing the shear capacity of slender concrete beams without stirrups and was found to have improved predictive abilities compared to the corresponding ACI equations. According to the analysis performed in this research work, it is deemed necessary to further enrich the current numerically generated database with additional data to further improve the dataset used for training and extrapolation. Finally, future research work foresees the study of beams with stirrups and deep beams for the development of improved predictive models.

• 한국융합학회논문지
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• 제13권5호
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• pp.307-312
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• 2022

본 연구에서는 종아리 근육에 기능성 의류를 착용한 것이 종아리의 근기능에 어떤 영향을 미치는지 규명하고 기능성 의류가 종아리 근기능 증가에 활용가치가 있는지 검증하고자 하는데 그 목적이 있다. 연구의 대상은 하지에 이상이 없는 B 대학교의 남학생 21명을 대상으로 측정 하였다. 측정방법은 등속성근기능측정기인 CSMI사의 Humac Norm을 이용하여 오른쪽, 왼쪽 종아리에 기능성 의류 착용 전, 후 각속도 30°/sec, 120°/sec로 측정하였다. 피실험자들이 기능성 의류를 착용했을 때와 착용하지 않았을 때를 측정 해본 결과 발목 배측굴곡(Dorsi flexion)에서는 기능성 의류를 착용했을 때와 착용하지 않았을 때 유의한 차이가 나타나지 않았으나, 발목 저측굴곡(Plantar flexion)에서는 기능성 의류를 착용하였을 때 근력, 근파워, 근지구력이 유의하게 증가하는 것으로 나타났다. 따라서 종아리의 기능성 의류 착용이 운동기능 향상에 긍정적 효과가 있으며, 향후 연구에서는 대회를 앞두고 훈련을 하는 선수에게 기능성 의류를 착용한 인원과 착용하지 않은 인원의 근기능 향상정도를 비교해보는 연구를 제시하는 바이다.

• 근관절건강학회지
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• 제16권1호
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• pp.55-65
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• 2009

Purpose: The purpose of this study was to determine the effects of water exercise program on physical fitness, pain and quality of life(QoL) in patients with osteoarthritis. Methods: Thirty-four old women were divided into the exercise(EG, n=18) and control groups(CG, n=16) after 6-week self-help education program. The EG carried out 6-week supervised water exercise program(60min/day, 2days/wk). Physical fitness, pain, and QoL were assessed by Senior Fitness Test Manual(Rikli & Jones, 2005), Pain rating scale(0-10) and World Health Organization QoL BREF(Min et al., 2000), respectively. Results: Both EG and CG increased upper and lower-body strength(all, p<.05), which were measured by arm curl and chair stand, respectively. For flexibility test, the EG increased upper and lower body(all, p<.05). Balance of the EG increased(p<.05), but not in the CG. Pain significantly decreased in the EG post training(p=.000). However, both EG and CG did not significantly improve for QoL. Conclusion: Six weeks of water exercise program did induce significant improvement in physical fitness and pain control in patients with osteoarthritis.

• International journal of advanced smart convergence
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• 제12권1호
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• pp.184-192
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• 2023

The purpose of this study was to compare and analyze the body composition, muscle circumference, and muscle activity of men in their 30s and 50s when the resistance exercise program was applied for 12 weeks, and to provide basic data for the preparation of the resistance exercise program for middle-aged men before entering old age. Nine men in their 30s and eleven 11 men in their 50s participated in the moderate intensity resistance exercise program for 12 weeks. Two weeks before the experiment, body composition, muscle circumference, and EMG were pre-tested, and then body composition and muscle circumference were additionally measured at the 8th week. Body composition, muscle circumference, and EMG were measured within 2 weeks after the 12 week exercise program. The measured data were compared and analyzed by Mixed design two-way ANOVA, and the following results were obtained. The body composition showed a significant difference only in the skeletal muscle mass, and it increased in the 30s group at 8 weeks. Muscle circumference did not show significant difference according to group and time. Muscle activity showed a significant difference according to group and time, and pectoralis major and triceps brachii showed a significant decrease to 30s group. The pectoralis major was higher in the 30s group at all times. In summary, when applying a 12-week resistance exercise program for young men and middle-aged men, the effect of improving muscle strength may appear similar, but they are not consistent, and it is thought that gradual changes in training variables are needed to improve muscle mass.

• Structural Engineering and Mechanics
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• 제86권4호
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• pp.487-501
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• 2023

Nanoparticles have lower size and larger specific surface area, good stability and less toxic and side effects. In recent years, with the development of nanotechnology, its application range has become wider and wider, especially in the field of biomedicine, which has received more and more attention. Bone defect repair materials with high strength, high elasticity and high tissue affinity can be prepared by nanotechnology. The purpose of this paper was to study how to analyze and study the composite materials for sports bone injury based on multifunctional nanomaterials, and described the electrospinning method. In this paper, nano-sized zirconia (ZrO₂) filled micro-sized hydroxyapatite (HAP) composites were prepared according to the mechanical properties of bone substitute materials in the process of human rehabilitation. Through material tensile and compression experiments, the performance parameters of ZrO₂/HAP composites with different mass fraction ratios were analyzed, the influence of filling ZrO₂ particles on the mechanical properties of HAP matrix materials was clarified, and the effect of ZrO₂ mass fraction on the mechanical properties of matrix materials was analyzed. From the analysis of the compressive elastic modulus, when the mass fraction of ZrO₂ was 15%, the compressive elastic modulus of the material was 1222 MPa, and when 45% was 1672 MPa. From the analysis of compression ratio stiffness, when the mass fraction of ZrO₂ was 15%, the compression ratio stiffness was 658.07 MPa·cm³/g, and when it was 45%, the compression ratio stiffness is 943.51MPa·cm³/g. It can be seen that by increasing the mass fraction of ZrO₂, the stiffness of the composite material can be effectively increased, and the ability of the material to resist deformation would be increased. Typically, the more stressed the bone substitute material, the greater the stiffness of the compression ratio. Different mass fractions of ZrO₂/HAP filling materials can be selected to meet the mechanical performance requirements of sports bone injury, and it can also provide a reference for the selection of bone substitute materials for different patients.

• 전기전자학회논문지
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• 제26권1호
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• pp.62-66
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• 2022

최근 데이터 기반의 딥러닝 기술을 적용하여 비면허 대역의 다양한 통신 신호를 분류하는 연구가 활발히 수행되고 있다. 하지만, 복잡한 신경망 모델 사용을 기반으로 이뤄진 이러한 접근법은 높은 연산 능력을 필요로 하게 되어, 자원 제약적인 무선 인터페이스 및 사물인터넷(Internet of Things) 장비에서는 사용이 제약된다. 본 연구에서는 비면허 대역의 무선 이기종 기술을 인지하기 위한 데이터 기반의 접근 방법을 살펴보고, 신호의 특징 추출 및 데이터화의 효율화 문제를 다룬다. 구체적으로, 비면허 대역의 다른 종류의 무선 통신 기술을 구분하기 위해 수신 신호 강도 측정을 기반으로 한 시계열 데이터를 이용해 합성곱 신경망(Convolutional Neural Network, CNN) 모델을 학습시켜 신호를 분류하는 방법을 살펴본다. 이 과정에서 동일한 구조의 신경망 모델의 경량화를 위한 효율적 신호의 시계열 데이터 정보 수집시 주파수 대역의 특징을 함께 특징화하는 방법을 제안하고, 그 효과를 평가한다. Bluetooth 호환의 Ubertooth 장비를 이용한 실측 기반의 실험 결과는 제안된 샘플링 기법이 동일한 신경망에 대해서 10% 수준의 샘플링 데이터 이용만으로도 동일한 정확도를 유지함을 보여준다.

• Structural Engineering and Mechanics
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• 제86권5호
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• pp.673-686
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• 2023

Determining the properties of pile from cone penetration test (CPT) is costly, and need several in-situ tests. At the present study, two novel hybrid learning models, namely PSO-RF and HHO-RF, which are an amalgamation of random forest (RF) with particle swarm optimization (PSO) and Harris hawks optimization (HHO) were developed and applied to predict the pile set-up parameter "A" from CPT for the design aim of the projects. To forecast the "A," CPT data along were collected from different sites in Louisiana, where the selected variables as input were plasticity index (PI), undrained shear strength (S_u), and over consolidation ratio (OCR). Results show that both PSO-RF and HHO-RF models have acceptable performance in predicting the set-up parameter "A," with R² larger than 0.9094, representing the admissible correlation between observed and predicted values. HHO-RF has better proficiency than the PSO-RF model, with R² and RMSE equal to 0.9328 and 0.0292 for the training phase and 0.9729 and 0.024 for testing data, respectively. Moreover, PI and OBJ indices are considered, in which the HHO-RF model has lower results which leads to outperforming this hybrid algorithm with respect to PSO-RF for predicting the pile set-up parameter "A," consequently being specified as the proposed model. Therefore, the results demonstrate the ability of the HHO algorithm in determining the optimal value of RF hyperparameters than PSO.

• 대한중풍순환신경학회지
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• 제14권1호
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• pp.102-106
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• 2013

■ Objectives The purpose of the this study was to investigate organization change(pennation angle) of lower extremity muscle in elderly with knee osteoarthritis through ultrasonic image. Also, we examined organizational change of muscle was by influenced after total knee replacement(TKR). ■ Methods Rectus femoris image was taken at 50% of the distance between the anterior superior iliac spine and the superior border of the patella. Vastus medialis image was taken at the most distal insertion level of vastus medialis on the medial border of the patella. measurements included the most distal insertion level of the vastus medialis on the medial border of the patella. ■ Results Change of pennation angle in rectus femoris showed decrease from 5.11° in preoperation to 4.29° in 1 week after operation. Change of pennation angle in vastus medialis showed decrease from 6.94° in preoperation to 5.76° in 1 week after operation. ■ Conclusion We consider decrease of pennation angle after total knee replacement in this study was casued by organizational change of muscle and this pennation angle was influenced force created by muscle. Therefore, we thinks that this pennation angle through ultrasonic image will be available to plane individual muscle exercise program and to confirm muscle mass by muscle strength training.

• 한국비블리아학회지
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• 제18권2호
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• pp.203-228
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• 2007

본 연구는 한 중 양국 대학교 학부생들의 도서관에 대한 인식수준 측정을 통해서 도서관의 성장과 발전에 장애요인이 되는 현안 문제를 규명하고 이에 대한 대응방안을 제시하기 위한 목적으로 수행되었다. 연구방법은 질문지기법을 사용하였다. 연구결과 도서관의 사회 및 문화적 기능에 대한 학부생들의 인식이 저조한 것으로 나타나 인식제고를 위한 도서관 문화행사를 강화시켜야 할 필요성이 있으며, 중국 학생들에 비해 한국 학생들의 학구열이 매우 낮고 아예 도서관을 찾지 않는 학생들이 많은 것으로 나타나 교과학습의 강도를 높이거나 도서관의 활용도를 높이는 유인정책이 필요하다. 또한 정보서비스에 대한 이용자의 만족제고 및 활성화를 위한 전문사서의 계속교육과 이용자에 대한 집단 및 그룹별 이용자 교육의 강화 도서관 이용을 통한 수업연계방안 프로젝트 등의 대응방안이 확립되어야 할 것이다.

• 한국노년학
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• 제29권3호
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• pp.823-835
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• 2009

본 연구의 목적은 12주간의 순환운동이 노인비만여성의 비만, 체력 및 대사증후군 지표에 미치는 영향을 살펴보고자 시도되었다. 65세 이상 체질량지수 25이상의 여성 자원자 총19명을 대상으로 12주간의 순환운동 프로그램을 실시하였으며, 운동 프로그램은 가벼운 유산소 운동과 스트레칭으로 준비운동을 실시 한 후 주 3회의 빈도로 매회 30분씩 12주 동안 순환운동 프로그램을 실시하였다. 12주간의 순환운동 프로그램 실시 후, 참가 전에 비해 참가 후의 체중과 체질량지수(p<.001)가 감소되었으며, 체력측정항목에서 하지근력(p<.001)과 상지 근력(p<.05), 상지 유연성(p<.05)과 하지연성(p<.05), 민첩성/동적평형성(p<.001), 전신지구력(p<.05)의 총 6개 모든 항목에서 유의한 향상이 있었고, 대사증후군 지표인 복부비만(p<.01), 수축기혈압(p<.05), 중성지방(p<.001), 고밀도 지단백(p<.01), 혈당(p<.05) 등 이완기 혈압을 제외한 모든 측정항목에서도 12주간의 순환운동 후 운동 참가 전에 비해 유의한 향상이 있었다. 결론적으로 12주간의 순환운동이 노인비만여성에 있어 체중감소와 체력향상에 긍정적인 영향을 미쳤으며, 대사증후군 지표의 개선에 효과적인 것으로 나타났다.