• Steel and Composite Structures
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• 제20권2호
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• pp.267-293
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• 2016

It is well known that, in order to accurately predict the behaviour of steel structures a requirement the definition of the mechanical behaviour of beam-to column joints is of primary importance. This goal can be achieved by means of the so-called component method, which, in order to obtain the whole behaviour of connections, provides to break up joints in basic components of deformability and resistance. One of the main joint components used to model bolted connections is the so-called equivalent T-stub in tension, which is normally used to predict the behaviour of bolted plates in bending starting from the behaviour of the single bolt rows. In past decades, significant research efforts have been devoted to the prediction of the behaviour of bolted T-stubs but, to date, no particular attention has been devoted to the characterization of their plastic deformation capacity. To this scope, the work presented in this paper, taking into account the existing technical literature, proposes a new theoretical model for predicting the whole behaviour up to failure of bolted T-stubs under monotonic loading conditions, including some complexities, such as the bolt/plate compatibility requirement and the bolt fracture, which are necessary to accurately evaluate the ultimate displacement. After presenting the advances of the proposed approach, a comparison between theoretical and experimental results is provided in order to verify its accuracy.

• 한국지역지리학회지
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• 제19권1호
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• pp.147-161
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• 2013

이 연구는 1960~70년대에 걸쳐 구서독에서 추진된 지방 행정구역 개편 배경과 과정 그리고 특성 및 평가를 고찰한 것이다. 독일의 하위 지방 행정구역에 해당하는 게마인데(Gemeinde)와 군(Kreis)과 자치시(Kreisfreie Stadt) 차원의 개편이 대대적으로 추진되었다. 구서독의 지방 행정구역의 개편은 행정개혁의 일환으로, 시대의 제반 요구를 수용하여 거점 도시망의 구성을 통한 소규모 행정구역의 통폐합으로 진행되었다. 구서독의 지방 행정구역 개편은 획일적인 구역설정, 지역 정체성의 혼란, 지방 자치권의 침해, 지역 계획적 관점의 우선 등에서 비판받고 있으나, 공공 행정의 수행 능력이 크게 향상되었으며, 특히 공공 서비스의 공급이 원활해지고 계획 역량이 제고된 것으로 평가받고 있다.

• 농촌계획
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• 제24권4호
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• pp.89-97
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• 2018

This is a comparative study on the policy of Korea and Japan for improving upland farming mechanization. Purpose of the study is to set a policy direction of improving efficiency of farm management by using agricultural machinery. Research topic is the agricultural mechanization policy at the national level. The research attempts to classify mechanization policies into framework plan, R&D, rent and lease program, upland farm promotion policies. Major features of the comparative analysis are followed. First, there is a similarity between policies of Korea and Japan in terms of the aim of framework plan and other policies settings. However, Japanese policies focus more on the joint management of farming than Korean policies. Japanese policies take an entire system covering from farm to market into account. Second, Japanese policies have much attention to the agricultural organizations such as corporate, cooperatives that are eligible for using agricultural machinery. This is different from Korean policy. Thus, upland farming mechanization policy needs to set priority, and to have systemic approach. Also, upland farming mechanization policy has to be facilitated in accordance with producer organizations and their marketing strategies.

• Structural Engineering and Mechanics
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• 제68권6호
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• pp.677-689
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• 2018

Residual deformation is a crucial index that should be paid special attention in the performance-based seismic analyses of reinforced concrete (RC) structures. Owing to their superior re-centering capacity under earthquake excitations, the post-tensioned self-centering (PTSC) RC frames have been proposed and developed for engineering application during the past few decades. This paper presents a comprehensive assessment on the seismic fragility of a PTSC frame by simultaneously considering maximum and residual deformations. Bivariate limit states are defined according to the pushover analyses for maximum deformations and empirical judgments for residual deformations. Incremental Dynamic Analyses (IDA) are conducted to derive the probability of exceeding predefined limit states at specific ground motion intensities. Seismic performance of the PTSC frame is compared with that of a conventional monolithic RC frame. The results show that, taking a synthetical consideration of maximum and residual deformations, the PTSC frame surpasses the monolithic frame in resisting most damage states, but is more vulnerable to ground motions with large intensities.

• 셀메드
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• 제9권3호
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• pp.4.1-4.8
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• 2019

Now researchers have focused attention on exploring the mechanism of acute responses of heat stress given in heat therapy that ultimately promotes the long term health benefits. Heat therapy is not a new idea rather it was practiced since thousands years back in the form of hot bath, sauna bath, steam room. Similarly in Ayurveda there is very comprehensive description of heat therapy in the form of Svedan karma (Sudation therapy). Svedan is a process to induce sweating artificially in a patient who had already undergone Snehan. Svedan is applied for purification of body, as well as in management of various disorders originated due to vitiation of Vata, Kapha Dosha, Meda Dhatu and musculoskeletal disorders. It produces various beneficial effects by augmenting the Agni like clears the channels, liquefies the deposited Dosha, regulates Vata Dosha, helps in removal and pacification of Dosha, augments metabolism (Agni Deepan), increases appetite, flexibility in body parts, softness and shining of skin, removes coldness, stiffness, drowsiness, improves joint motility. However, Svedana karma is vastly used by Ayurveda Physicians in treatment of various disorders but the mechanisms of beneficial effects produced by Svedan Karma are yet not completely explored on scientific basis. In this article, we will discuss and try to establish a possible mechanism of action of Svedana karma in relation to heat stress, mitochondrial adaptation, heat shock protein (HSP) and glucocorticoids as these are secreted under stressful conditions.

• Clinics in Shoulder and Elbow
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• 제25권3호
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• pp.188-194
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• 2022

Background: Medial elbow laxity develops in throwing athletes due to valgus forces. Medial elbow instability in professional, collegiate, and high school athletes is well documented; however, the medial elbow of young throwing athletes has received less attention. This study investigated the medial elbow and common flexor tendon during applied elbow valgus stress of youth baseball players. Methods: The study included 15 participants. The medial elbow width and thickness of the common flexor tendon were measured on ultrasound images. Results: No significant side differences in medial elbow width or common flexor tendon were found at rest or under applied valgus stress. At rest, the medial elbow joint width was 3.34±0.94 mm on the dominant side and 3.42±0.86 mm on the non-dominant side. The dominant side increased to 3.83±1.02 mm with applied valgus stress, and the non-dominant side increased to 3.96±1.04 mm. The mean flexor tendon thickness was 3.89±0.63 mm on the dominant side and 4.02±0.70 mm on the non-dominant side. Conclusions: These findings differ from similar studies in older throwing athletes, likely because of the lack of accumulated stress on the medial elbow of youth throwing athletes. Maintaining elbow stability in young throwing athletes is a vital step to preventing injury later in their careers.

• 한국기계가공학회지
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• 제21권9호
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• pp.63-70
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• 2022

Laser welding has attracted great attention as a tool used to join electrical steel coils. In this study, laser butt welding for electrical steel coil joining was conducted using the Taguchi method. It was found that structural defects such as void sand cracks were not produced in welds. This indicated that the performance of laser welding in electrical steel was excellent. According to the Taguchi analysis, the total welding quality index (TWQI) considering the bead height and roughness and tensile strength of the weld joint was almost evenly affected by laser power, welding speed, and focal position. The optimum welding conditions to maximize the TWQI were a laser power of 1220W, welding speed of 90 mm/s, and a focal position of 1mm. The regress model predicting the TWQI was also developed using the surface response method. We found that the model predicts measured values with an average error of 16.36%.

• 한국운동역학회지
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• 제32권4호
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• pp.134-140
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• 2022

Objective: This study aims to verify effect of 1-RM direct measurement method of back squat on beginners. Method: Total of 8 healthy adults were recruited for this study (age: 29 ± 3.81 yrs., height: 174 ± 3.83 cm., body mass: 74 ± 11.63 kg., 1RM: 96 ± 19.78 kg). All participants performed the back squat with 80%, 90% and 100% of the pre-measured 1RM. A three-dimensional motion analysis was performed with 8 infrared cameras and 3 channels of EMG were used for this study. One-way ANOVA with repeated measure was used for the statistical analysis with the significant level set to α=.05. Results: The ankle joint ROM in the transverse plane was significantly increased as the weight increased during the concentric contraction phase 2 (p < .05). In addition, the erector spinae and the gluteus maximus, which are synergist for the motion, showed a significant difference according to the increased weight (p < .05). Conclusion: Our results revealed that beginners increase potential dynamic knee valgus as weight increased. Therefore, it is thought that field coaches should pay attention to this to minimize and prevent injuries when measuring 1-RM for beginners.

• Smart Structures and Systems
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• 제29권1호
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• pp.207-220
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• 2022

Structural health monitoring (SHM) plays a vital role in the maintenance and operation of constructions. In recent years, autonomous inspection has received considerable attention because conventional monitoring methods are inefficient and expensive to some extent. To develop autonomous inspection, a potential approach of crack identification is needed to locate defects. Therefore, this study exploits two deep learning-based segmentation models, DeepLabv3+ and Mask R-CNN, for crack segmentation because these two segmentation models can outperform other similar models on public datasets. Additionally, impacts of label quality on model performance are explored to obtain an empirical guideline on the preparation of image datasets. The influence of image cropping and label refining are also investigated, and different strategies are applied to the dataset, resulting in six alternated datasets. By conducting experiments with these datasets, the highest mean Intersection-over-Union (mIoU), 75%, is achieved by Mask R-CNN. The rise in the percentage of annotations by image cropping improves model performance while the label refining has opposite effects on the two models. As the label refining results in fewer error annotations of cracks, this modification enhances the performance of DeepLabv3+. Instead, the performance of Mask R-CNN decreases because fragmented annotations may mistake an instance as multiple instances. To sum up, both DeepLabv3+ and Mask R-CNN are capable of crack identification, and an empirical guideline on the data preparation is presented to strengthen identification successfulness via image cropping and label refining.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제8권12호
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• pp.491-498
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• 2019

디지털 트윈은 현실 세계의 물리적인 사물을 컴퓨터상에 동일하게 가상화시키는 기술로써, IoT을 통해 센서 데이터를 수집하고, 수집한 데이터를 활용하여 물리적인 사물과 가상 사물을 양방향으로 연결을 할 수 있게 한다. 디지털 트윈 기술은 가상 모델의 시뮬레이션을 통해 동작을 조정하고 환경변화에 대한 대응을 미리 실험하여 위험성을 최소화할 수 있는 장점을 지닌다. 최근 인공지능이나 기계학습에 관련된 기술들이 주목받기 시작하면서, 물리적인 사물의 동작을 가상화하여 가상 모델을 관찰하고 다양한 시나리오를 적용하려는 시도가 증가하고 있다. 특히, 인더스트리 4.0에서 공장자동화의 핵심인 협력 로봇의 디지털 트윈을 구축하기 위해서는 로봇의 동작을 인지하는 과정이 필수적으로 요구된다. 로봇의 동작을 인지하기 위한 모델링 기반의 연구에 비해 센서 데이터 기반으로 동작을 예측하는 연구는 미비한 상황이다. 따라서 본 논문에서는 로봇의 동작을 인지하기 위해 가정용 협력 로봇에서 전류 및 관성 센서 데이터를 수집하기 위한 실험 환경을 구축하고, 수집한 센서 데이터를 기반으로 한 동작 예측 모델을 제안하고자 한다. 제안하는 방식은 조인트 위치 기반으로 로봇의 동작 명령어를 9가지로 분류하고 전류와 관성 센서값을 사용하여 학습을 통해 예측하는 방식이다. 이때, 학습에 사용되는 데이터는 협력 로봇이 동작 명령어의 입력 파라미터에 마진을 가지고 작동할 때 수집되는 센서값이다. 이를 통해, 동일한 경로를 따라 이동하는 9가지 동작뿐만 아니라 각 동작과 비슷한 경로를 따라 이동하는 동작에 대해서도 예측하는 모델을 구축하였다. SVM을 이용하여 학습한 결과, 모델의 성능은 평균적으로 정확도, 정밀도, 및 재현율이 모두 97%로 평가되었다.