• Steel and Composite Structures
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• v.18 no.5
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• pp.1197-1214
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• 2015

There is a great difference in mechanical behavior between design model one-time loading and step-by-step construction process. This paper presents practical computational methods for simulating the structural behavior of long-span rigid steel structures during construction processes. It introduces the positioning principle of node rectification for installation which is especially suitable for rigid long-span steel structures. Novel improved nonlinear analytical methods, known as element birth and death of node rectification, are introduced based on several calculating methods, as well as a forward iteration of node rectification method. These methods proposed in this paper can solve the problem of element's 'floating' and can be easily incorporated in commercial finite element software. These proposed methods were eventually implemented in the computer simulation and analysis of the main stadium for the Universiade Sports Center during the construction process. The optimum construction scheme of the structure is determined by the improved algorithm and the computational results matched well with the measured values in the project, thus indicating that the novel nonlinear time-varying analysis approach is effective construction simulation of complex rigid long-span steel structures and provides useful reference for future design and construction.

• Journal of Korean Association for Spatial Structures
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• v.21 no.1
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• pp.95-104
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• 2021

As people's living standards and cultural standards have developed, interest in culture and art has increased, and the demand for large space structures where people can enjoy art, music, and sports has increased. As it accommodates a large number of personnel, it is most important to ensure safety of large spatial structures, and can be used as a space where people can evacuate in case of a disaster. Large spatial structures should be prepared for earthquake loads rather than wind loads. In addition to damage to the structure due to earthquakes, there are cases in which it was not utilized as a space for evacuation due to the fall of objects installed on top of the structure. Therefore, in this study, the dome-shaped large spatial structure is generalized and the displacement response according to the number of installations, position and mass is analyzed using a tuned mass damper(TMD) that is representative vibration control device.

• Steel and Composite Structures
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• v.49 no.5
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• pp.487-502
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• 2023

In the realm of nanotechnology, the nonlocal strain gradient theory takes center stage as it scrutinizes the behavior of spinning cantilever nanobeams and nanotubes, pivotal components supporting various mechanical movements in sport structures. The dynamics of these structures have sparked debates within the scientific community, with some contending that nonlocal cantilever models fail to predict dynamic softening, while others propose that they can indeed exhibit stiffness softening characteristics. To address these disparities, this paper investigates the dynamic response of a nonlocal cantilever cylindrical beam under the influence of external discontinuous dynamic loads. The study employs four distinct models: the Euler-Bernoulli beam model, Timoshenko beam model, higher-order beam model, and a novel higher-order tube model. These models account for the effects of functionally graded materials (FGMs) in the radial tube direction, giving rise to nanotubes with varying properties. The Hamilton principle is employed to formulate the governing differential equations and precise boundary conditions. These equations are subsequently solved using the generalized differential quadrature element technique (GDQEM). This research not only advances our understanding of the dynamic behavior of nanotubes but also reveals the intriguing phenomena of both hardening and softening in the nonlocal parameter within cantilever nanostructures. Moreover, the findings hold promise for practical applications, including drug delivery, where the controlled vibrations of nanotubes can enhance the precision and efficiency of medication transport within the human body. By exploring the multifaceted characteristics of nanotubes, this study not only contributes to the design and manufacturing of rotating nanostructures but also offers insights into their potential role in revolutionizing drug delivery systems.

• Journal of Biomedical Engineering Research
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• v.26 no.5
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• pp.283-294
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• 2005

The Center for Imaging Human Structures (CIH) was established in December 2002 to develop new diagnostic imaging techniques and to make them available to the greater community of biomedical and clinical researchers at Sungkyunkwan University. CIH has been involved in 5 specific activities to provide solutions for early diagnosis and improved treatment of human diseases. The five area goals include: 1) development of a digital mammography system with computer aided diagnosis (CAD); 2) development of digital radiological imaging techniques; 3) development of unified medical solutions using 3D image fusion; 4) development of multi-purpose digital endoscopy; and, 5) evaluation of new imaging systems for clinical application

• Journal of Korean Association for Spatial Structures
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• v.16 no.4
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• pp.91-100
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• 2016

A retractable-roof spatial structure is frequently used for a stadium and sports hall. A retractable-roof spatial structure allows natural lighting, ventilation, optimal conditions for grass growth with opened roof. It can also protects users against various weather conditions and give optimal circumstances for different activities. Dynamic characteristics of a retractable-roof spatial structure is changed based on opened or closed roof condition. A tuned mass damper (TMD) is widely used to reduce seismic responses of a structure. When a TMD is properly tuned, its control performance is excellent. Opened or closed roof condition causes dynamic characteristics variation of a retractable-roof spatial structure resulting in off-tuning. This dynamic characteristics variation was investigated. Control performance of a passive TMD and a smart TMD were evaluated under off-tuning condition.

• Advances in nano research
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• v.14 no.3
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• pp.235-246
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• 2023

Nanotechnology, like any other revolutionary innovation in materials science, has significantly influenced the level of competition in sports. Nanotechnology provides various benefits and enormous potential to enhance athletic equipment, making players safer, more comfortable, and more agile. Various sporting equipment is being infused with nanomaterials, including carbon nanotubes (CNTs), silica nanoparticles (SNPs), nanoclays fullerenes, etc., to enhance athlete and equipment performance. Each of these nanomaterials gives athletic equipment an extra benefit like high strength and stiffness, longevity, decreased weight, abrasion resistance, etc. This paper mechanically analysis the structural strength of tennis equipment to avoid injury. As a result, the bending forces are applied to the reinforced structures to investigate their durability.

• Journal of Navigation and Port Research
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• v.32 no.8
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• pp.645-652
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• 2008

The interest on the marine leisure sports is rapidly increasing with the advent of the five-day week and with increments of GNP. The self-governing bodies are trying to drag large investments into the marine leisures industry through international exhibitions and yacht rallies. Unfortunately, the demands in the domestic area don't increase differently from those demand patterns in the advanced countries. In this study, several suggestions for vitalizations on the marine leisure industry are made after surveying the recognition degree of the domestic people on the marine leisures and the current states of their spending on the marine leisures. As results, it has been shown that the policies based upon negative factors coming from negative understandings on the leisure activities should be largely revised. Further, it seems that the policies for the preparations of the laws and the regulations for the marine leisures as well as for the R&D policies should be taken systematically so that the infra structures are constructed while improving the negative understandings on the leisures. The fundamental databases investigated in this study will help the policy makers and the investors reduce the risks of the policy and the investments in the field of marine leisure sports.

• Journal of Korean Orthopaedic Sports Medicine
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• v.2 no.2
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• pp.86-91
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• 2003

Ligaments are functionally very important structures in the joints of human. Many studies have been performed about injury mechanisms and mechanical properties of ligaments. Although treatment methods of injured ligaments have continually improved, many questions still remain about enhancing the rate, quality and completeness of ligament healing. For studies and understanding of the healing of ligaments that have important functions in the joint, this article reviews histological characteristics, mechanical properties and process of healing.

• Journal of Korean Orthopaedic Sports Medicine
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• v.2 no.2
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• pp.119-126
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• 2003

The shoulder is a complex joint and, by virtue of having a large range of motion, is inherently unstable, relying on the surrounding soft tissue structures for stability. The bony joint consists of the glenoid, acromion, and humoral head, while the soft tissues include the glenoid labrum, the glenohumeral ligaments. and coracoacromial ligament as well as the muscles of the rotator cuff, the long head of the biceps, and the scapulothoracic muscles. Dysfunction in any one of these components can cause shoulder problems. The throwing motion involves a series of phases that stress to their limits the dynamic and static restraints of the glenohumeral and scapulothoracic joints. . Therefore, maintaining a balance of proper biomechanical forces is essential to avoiding shoulder injuries in throwing athletes. Over the last decade, signficant advances have been made in the study and understanding of the shoulder mechanics, and pathophysiology of injury. Additionally, advances in surgical techniques, particularly arthroscopy , have aided in the diagnosis of and the developement of less invasive surgical treatments for injuries that do not respond to nonoperative measures. In this article, we reviewed the pathophysiology of injuries , diagnostic techniques, and surgical management of shoulder injuries in throwing athletes .

• Clinics in Shoulder and Elbow
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• v.8 no.1
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• pp.5-8
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• 2005

Rotator interval should be as loose as possible, though not so loose as to break the shoulder mechanism. This region is a source of significant shoulder pathology resulting in patient discomfort and dysfunction. The clinical features fall into two categories. Rotator interval tightness is associated with impingement, contracture with adhesive capsulitis, and widening with anteroinferior, posterior or multidirectional instability. Coracoid impingement can cause damage to the structures of the rotator interval, Injury of the interval are associated with subscapularis tears as well as biceps tendinitis, fraying, subluxation, and dislocation. An understanding of the normal and pathologic anatomy can lead to successful diagnosis and treatment of lesions in the rotator interval.