• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.27 no.6
• /
• pp.663-672
• /
• 2014

Recently, modular structural systems have been applicable to building construction since they can significantly reduce building construction time. They consists of several unit modular frames of which each beam-column joint employs an access hole for connecting unit modular frames. Their structural design is usually carried out under the assumption that their load-carrying mechanism is similar to that of a traditional steel moment-resisting system. In order to obtain the validation of this assumption, the cyclic characteristics of beam-column joints in a unit modular frame should be investigate. This study carried out finite element analyses(FEM) of unit modular frames to investigate the cyclic behavior of beam-column joints with the structural influence of access holes. Analysis results show that the unit modular frames present stable cyclic response with large deformation capacities and their joints are classified into partial moment connections. Also, this study develops a simple spring model for earthquake nonlinear analyses and suggests the Ramberg-Osgood hysteretic rule to capture the cyclic response of unit modular frames.

• Structural Monitoring and Maintenance
• /
• v.6 no.4
• /
• pp.365-387
• /
• 2019

This study aims to provide useful information on the fatigue assessment of a top-tensioned riser (TTR) subjected to vortex-induced vibration (VIV) by performing parametric study. The effects of principal design parameters, i.e., riser diameter, wall thickness, water depth (related to riser length), top tension, current velocity, and shear rate (or shear profile of current) are investigated. To prepare the base model of TTR for parametric studies, three (3) riser modelling techniques in the OrcaFlex were investigated and validated against a reference model by Knardahl (2012). The selected riser model was used to perform parametric studies to investigate the effects of design parameters on the VIV fatigue damage of TTR. From the obtained comparison results of VIV analysis, it was demonstrated that a model with a single line model ending at the lower flex joint (LFJ) and pinned connection with finite rotation stiffness to simulate the LFJ properties at the bottom end of the line model produced acceptable prediction. Moreover, it was suitable for VIV analysis purposes. Findings from parametric studies showed that VIV fatigue damage increased with increasing current velocity, riser outer diameter and water depth, and decreased with increasing shear rate and top tension of riser. With regard to the effects of wall thickness, it was not significant to VIV fatigue damage of TTR. The detailed outcomes were documented with parametric study results.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.3A
• /
• pp.223-231
• /
• 2011

It has been shown that the performance of multiple-input multiple-output (MIMO) spatial multiplexing systems is significantly degraded when spatial correlation exists between transmit and receive antenna pairs. In this paper, we investigate designs of a new statistical precoder for spatial multiplexing systems with maximum likelihood (ML) receiver which requires only correlation statistics at the transmitter. Two kinds of closed-form solution precoders based on rotation and power allocation are proposed by means of maximizing the minimum E tlidean distance of joint symbol constellations. In addition, we extend our results to linear receivers for correlated channels. We provide a method which yields the same profits from the proposed precoders based on a simple zero-forcing (ZF) receiver. The simulation shows that 2dB and 8dB gains are achieved for ML and ZF systems with two transmit antennas, respectively, compared to the conventional systems.

• Clinics in Shoulder and Elbow
• /
• v.12 no.2
• /
• pp.236-239
• /
• 2009

Purpose: We wanted to evalulate the clinical results of pectoris major tendon transfer for a neglected winged scapula that was caused by paralysis of the serratus anterior due to injury to the long thoracic nerve. Materials and Methods: A patient had neglected winged scapula that followed an arthroscopic operation for multi-directional instability of the shoulder joint, which was caused by traumatic dislocation. The patient was treated with pectoralis major tendon transfer using the modified Eden-Lange procedure. The range of a motion was improved from forward flexion $90^{\circ}$ and external rotation $70^{\circ}$ to $170^{\circ}$ and $150^{\circ}$ respectively. Results and Conclusion: There were no complications or recurrence and the patient's psychological satisfaction was also high. If the shoulder girdle muscles are intact, except for the serratus anterior, then pectoralis tendon transfer is a satisfactory method that can provide normal scapulo-thoracic motion.

• Archives of Plastic Surgery
• /
• v.45 no.1
• /
• pp.62-68
• /
• 2018

Background Amputation is commonly performed for toe necrosis secondary to peripheral vascular diseases, such as diabetes mellitus. When amputating a necrotic toe, preservation of the bony structure is important for preventing the collapse of adjacent digits into the amputated space. However, in the popular terminal Syme's amputation technique, partial amputation of the distal phalanx could cause increased tension on the wound margin. Herein, we introduce a new way to resect sufficient bony structure while maintaining the normal length, based on a morphological analysis of the toes. Methods Unlike the pulp of the finger in the distal phalanx, the toe has abundant teardrop-shaped pulp tissue. The ratio of the vertical length to the longitudinal length in the distal phalanx was compared between the toes and fingers. Amputation was performed at the proximal interphalangeal joint level. Then, a mobilizable pulp flap was rotated $90^{\circ}$ cephalad to replace the distal soft tissue defect. This modified toe fillet flap was performed in 5 patients. Results The toe pulp was found to have a vertically oriented morphology compared to that of the fingers, enabling length preservation through cephalad rotation. All defects were successfully covered without marginal ischemia. Conclusions While conventional toe fillet flap coverage focuses on the principle of length preservation as the first priority, our modified method takes both wound healing and length into account. The fattiest part of the pulp is advanced to the toe tip, providing a cushioning effect and enough length to substitute for phalangeal bone loss. Our modified method led to satisfactory functional and aesthetic outcomes.

• Physical Therapy Rehabilitation Science
• /
• v.8 no.2
• /
• pp.74-78
• /
• 2019

Objective: Myofascial release (MFR) is used to restore tissue extensibility of the fascia tissue and is considered to be useful in a number of clinical settings, such as low back pain (LBP). Dynamic myofascial release (DMFR) is the manual therapy, which combined the conventional MFR with the joint mobilization. The purpose of this study was to investigate the effects of the DMFR on trunk mobility, and furthermore, whether the increase of trunk mobility can carry over the improvement of dynamic standing balance in persons with chronic nonspecific LBP. Design: Randomized controlled trial. Methods: Thirty persons with chronic non-specific LBP participated in the study and were randomly assigned to the DMFR group (n=15) or the control group (n=15). DMFR was performed for two sessions (15 minutes/session) per week for four weeks for the treatment group. Both the DMFR and control groups were allowed to perform low-intensity physical activities during the treatment period. The Modified-modified $Sch{\ddot{o}}ber$ test (MMST) for trunk mobility and the Functional Reach Test (FRT) for dynamic standing balance were measured before and after the treatment period in both the DMFR group and the control group. Results: The MMST value of DMFR group increased significantly in all trunk range of motion (flexion, extension, lateral flexion, and rotation) after treatment, compared with the control group (p<0.05). Additionally, the FRT value of the DMFR group improved significantly after treatment, compared with the control group (p<0.05). Conclusions: We suggest that DMFR have a positive effect on trunk mobility and standing balance in persons with chronic LBP.

• Steel and Composite Structures
• /
• v.29 no.5
• /
• pp.603-622
• /
• 2018

Precast concrete structures are erected from individual prefabricated components, which are assembled on-site using different types of connections. In the present design of these structures, beam-to-column connections are assumed pin jointed. Bolted billet beam to-column connections have been used in the precast concrete industry for many years. They have many advantages over other jointing methods in component production, quality control, transportation and assembly. However, there is currently limited information concerning their detailed structural behaviour under vertical loadings. The experimental work has involved the determination of moment-relative rotation relationships for semi-rigid precast concrete connections in full-scale connection tests. The study reported in this paper was undertaken to clarify the behaviour of such connections under symmetrical vertical loadings. A series of full-scale tests was performed on sample column for which the column geometry and bolt arrangements conformed to successful commercial practice. Proprietary hollow core floor slabs were tied to the beams by 2T25 tensile reinforcing bars, which also provide the in-plane continuity across the connections. The contribution of the floor strength and stiffness to the flexural capacity of the joint is currently neglected in the design process for precast concrete frames. The flexural strength of the connections in the double-sided tests was at least 0.93 times the predicted moment of resistance of the composite beam and slab. The secant stiffness of the connections ranged from 0.94 to 1.94 times the flexural stiffness of the attached beam. In general, the double-sided connections were found to be more suited to a semi-rigid design approach than the single sided ones. The behaviour of double sided bolted billet connection test results are presented in this paper. The behaviour of single sided bolted billet connection test results is the subject of another paper.

• Structural Engineering and Mechanics
• /
• v.71 no.1
• /
• pp.57-63
• /
• 2019

During the last two decades, much joint research regarding vibration based methods has been done, leading to developing various algorithms and techniques. These algorithms and techniques can be divided into modal methods and signal methods. Although modal methods have been widely used for health monitoring and damage detection, signal methods due to higher efficiency have received considerable attention in various fields, including aerospace, mechanical and civil engineering. Signal-based methods are derived directly from the recorded responses through signal processing algorithms to detect damage. According to different signal processing techniques, signal-based methods can be divided into three categories including time domain methods, frequency domain methods, and time-frequency domain methods. The frequency domain methods are well-known and interest in using them has increased in recent years. To determine dynamic behaviours, to identify systems and to detect damages of bridges, different methods and algorithms have been proposed by researchers. In this study, a new algorithm to detect seismic damage in the bridge's piers is suggested. To evaluate the algorithm, an analytical model of a bridge with simple spans is used. Based on the algorithm, before and after damage, the bridge is excited by a sine force, and the piers' responses are measured. The dynamic specifications of the bridge are extracted by Power Spectral Density function. In addition, the Least Square Method is used to detect damage in the bridge's piers. The results indicate that the proposed algorithm can identify the seismic damage effectively. The algorithm is output-only method and measuring the excitation force is not needed. Moreover, the proposed approach does not need numerical models.

• Clinics in Shoulder and Elbow
• /
• v.22 no.4
• /
• pp.220-226
• /
• 2019

Background: This retrospective study was undertaken to evaluate mid-term clinical and radiological outcomes of lattisimus dorsi (LD) tendon transfer in patients with irreparable massive rotator cuff tears (MRCT). We hypothesize that LD tendon transfer would provide safe and satisfactory clinical outcomes at mid-term follow-up. Methods: From November 2008 to December 2016, 23 patients ($57.5{\pm}4.4years$; 20 male, 3 female) who underwent LD tendon transfer for massive tears, were enrolled. Inclusion criteria were irreparable MRCT. Exclusion criteria included full thickness subscapularis tear, rotator cuff arthropathy, anterosuperior rotator cuff tear, and osteoarthritis. Mean follow-up period was $4.7{\pm}4.0years$ (range, 2-12 years). Clinical assessment (American Shoulder and Elbow Surgeons [ASES], University of California, Los Angeles [UCLA], Simple Shoulder Test [SST]) and radiographic assessment (osteoarthritis [OA], acromiohumeral distance [AHI]) were evaluated. Results: ASES, UCLA and SST scores, and range of motion (ROM), except internal rotation, improved significantly at the last followup (p<0.05). Also, AHI was significantly improved at the last follow-up, from 6.6 mm to 8.2 mm (p=0.008). At the final follow-up, the radiologic stages of the glenohumeral osteoarthritis were determined as stage 1 in 9 patients, stage 2 in 10 patients, stage 3 in 2 patients, and stage 4 in 2 patients. Complications were observed in 21.7% cases: 3 re-tears and 2 infections were noted in our study. Conclusions: LD tendon transfer for irreparable MRCT provides satisfactory clinical outcomes at mid-term follow-up. Mild degenerative osteoarthritis (stage 1, 2) of the shoulder joint are common at the mid-term follow-up. Also, complications such as tear, infection should be considered.

• International Journal of Computer Science & Network Security
• /
• v.21 no.2
• /
• pp.110-119
• /
• 2021

The Coronavirus or COVID-19 is contagiousness virus that infected almost every single part of the world. This pandemic forced a major country did lockdown and stay at a home policy to reduce virus spread and the number of victims. Interactions between humans and robots form a popular subject of research worldwide. In medical robotics, the primary challenge is to implement natural interactions between robots and human users. Human communication consists of dynamic processes that involve joint attention and attracting each other. Coordinated care involves sharing among agents of behaviours, events, interests, and contexts in the world from time to time. The robotics arm is an expensive and complicated system because robot simulators are widely used instead of for rehabilitation purposes in medicine. Interaction in natural ways is necessary for disabled persons to work with the robot simulator. This article proposes a low-cost rehabilitation system by building an arm gesture tracking system based on a depth camera that can capture and interpret human gestures and use them as interactive commands for a robot simulator to perform specific tasks on the 3D block. The results show that the proposed system can help patients control the rotation and movement of the 3D arm using their hands. The pilot testing with healthy subjects yielded encouraging results. They could synchronize their actions with a 3D robotic arm to perform several repetitive tasks and exerting 19920 J of energy (kg.m².S^-2). The average of consumed energy mentioned before is in medium scale. Therefore, we relate this energy with rehabilitation performance as an initial stage and can be improved further with extra repetitive exercise to speed up the recovery process.