• Steel and Composite Structures
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• v.24 no.5
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• pp.561-568
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• 2017

Steel frames are widely used in steel structures. Exiting steel structures may be needed to strengthen for various reasons. Carbon Fiber Reinforced Polymers (CFRP) is one of the materials that are used to strengthen steel structures. Most studies on strengthening steel structures have been done on beams and steel columns. No independent study, to the researcher's knowledge, has studied the effect of CFRP strengthening on steel frames. This study explored the use of CFRP composite on retrofitting square hollow section (SHS) steel frames, using numerical investigations. Ten Finite Element (FE) models, which were strengthened with CFRP sheets, were analyzed under different coverage length, number of layers, and location of CFRP composite. One FE model without strengthening was analyzed as a control FE model to determine the increase of the ultimate load in the strengthened steel frames. ANSYS software was used to analyze the SHS steel frames. The results showed that the coverage length and the number of layers of CFRP composite have a significant effect on increasing the ultimate load of the SHS steel frames. The results also showed that the location of CFRP composite had no similar effect on increasing the ultimate load and the amount of mid span deflection of the SHS steel frames.

• Steel and Composite Structures
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• v.25 no.5
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• pp.593-601
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• 2017

Carbon Fiber Reinforced Polymer (CFRP) is one of the materials used to strengthen steel structures. Most studies on strengthening steel structures have been done on steel beams and steel columns. No independent study, to the researcher's knowledge, has studied the effect of CFRP strengthening on steel beam-columns, and it seems that there is a lack of understanding on behavior of CFRP strengthening on steel beam-columns. However, this study explored the use of adhesively bonded CFRP flexible sheets on retrofitting square hollow section (SHS) steel beam-columns, using numerical investigations. Finite Element Method (FEM) was employed for modeling. To determine the ultimate load of SHS steel beam-columns, ten specimens, eight of which were strengthened with the different coverage length and with one and two CFRP layers, with two types of section (Type A and B) were analyzed. ANSYS was used to analyze the SHS steel beam-columns. The results showed that the CFRP composite had no similar effect on the slender and stocky SHS steel beam-columns. The results also showed that the coverage length, the number of layers, and the location of CFRP composites were effective in increasing the ultimate load of the SHS steel beam-columns.

• Steel and Composite Structures
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• v.23 no.1
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• pp.87-94
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• 2017

Steel structures often require strengthening due to the increasing life loads, or repair caused by corrosion or fatigue cracking. Carbon Fiber Reinforced Polymers (CFRP) is one of the materials used to strengthen steel structures. Most studies on strengthening steel structures have been carried out on steel beams and steel columns under centric compression load. No independent article, to the author's knowledge, has studied the effect of CFRP strengthening on steel columns under eccentric compression load, and it seems that there is a lack of understanding on behavior of CFRP strengthening on steel columns under eccentric compression load. However, this study explored the use of adhesively bonded CFRP flexible sheets on retrofitting square hollow section (SHS) steel columns under the eccentric compression load, using numerical investigations. Finite Element Method (FEM) was employed for modeling. To determine ultimate load of SHS steel columns, eight specimens with two types of section (Type A and B), strengthened using CFRP sheets, were analyzed under different coverage lengths, the number of layers, and the location of CFRP composites. Two specimens were analyzed without strengthening (control) to determine the increasing rate of the ultimate load in strengthened steel columns. ANSYS was used to analyze the SHS steel columns. The results showed that the CFRP composite had no similar effect on the slender and stocky SHS steel columns. The results also showed that the coverage length, the number of layers, and the location of CFRP composites were effective in increasing the ultimate load of the SHS steel columns.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.8
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• pp.2606-2626
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• 2022

In this paper, a unmanned aerial vehicle (UAV) access deployment algorithm is proposed, which is based on an improved virtual force model to solve the poor coverage quality of UAVs caused by limited number of UAVs and random mobility of users in the deployment process of UAV base station. First, the UAV-adapted Harris Hawks optimization (U-AHHO) algorithm is proposed to maximize the coverage of users in a given hotspot. Then, a virtual force improvement model based on user perception (UP-VFIM) is constructed to sense the mobile trend of mobile users. Finally, a UAV motion algorithm based on multi-virtual force sharing (U-MVFS) is proposed to improve the ability of UAVs to perceive the moving trend of user equipments (UEs). The UAV independently controls its movement and provides follow-up services for mobile UEs in the hotspot by computing the virtual force it receives over a specific period. Simulation results show that compared with the greedy-grid algorithm with different spacing, the average service rate of UEs of the U-AHHO algorithm is increased by 2.6% to 35.3% on average. Compared with the baseline scheme, using UP-VFIM and U-MVFS algorithms at the same time increases the average of 34.5% to 67.9% and 9.82% to 43.62% under different UE numbers and moving speeds, respectively.

• Archives of Reconstructive Microsurgery
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• v.14 no.2
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• pp.131-137
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• 2005

The extensor digitorum brevis (EDB) muscle island flap is a reliable, safe method for coverage of foot and ankle. There are many variation in approach such as curvilinear, zigzag, L-shaped or vertical longitudinal incision for exposure of the EDB muscle. These approaches use only single incision excluding the distal incision for exposure of the distal tendon. Since dorsalis pedis artery vascular bundle and sinus tarsi branch of the lateral tarsal artery both requires careful dissection, single incision alone may cause not only difficulty in exposure but also skin sloughing at donor site. So we tried to modify the approach into two parallel longitudinal incision, one for dorsalis pedis vascular bundle and the other for sinus tarsi branch exposure. The author treated 9 patient with EDB muscle flap. We used single incision in six patients, and two parallel incision in three patients. All the flap survived. In two parallel incision group, dissection was more easy and rapid. So we would like to suggest that two parallel longitudinal incision approach is better method than the single incision technique for exposure of the EDB muscle flap.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.526-529
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• 2003

This paper presents two strategies to refute clock cycles when using stopping rule in VHDL model verification. The first method is that a semi-random variable is defined and the data that stay in the range of semi-random variable are skipped when stopping rule is running. The second one is to keep the old values of parameters when phases are changed. 12 VHDL models are examined to observe the effectiveness of strategies.

• Journal of Sericultural and Entomological Science
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• v.30 no.2
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• pp.84-87
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• 1988

Tow Soil fumigants, cylon and chloropiclin were examined for mulberry graftage growth on the nursery garden. Thirty ml/$m^2$ of each fumigants was injected and followed vinyl coverage 4 weeks before planting. Fumigants increased clearly diameter and branch length of graftages, and controled weeds occurance. These effects showed a little bit higher in chloropiclin than in cylon, but no difference statistically at 5% LSD.

• Archives of Reconstructive Microsurgery
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• v.16 no.2
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• pp.68-74
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• 2007

Soft-tissue reconstruction of the foot and ankle has long been a challenge for reconstructive surgeons. Limitations in the available local tissue and donor-site morbidity restrict the options. In an effort to solve these difficult problems, the authors have begun to use a subcutaneous fascial pedicled lateral supramalleolar flap. This report presents the authors' experience with five patients treated with this flap. The patients’ ages ranged from 26 to 72 years; four of the patients were male and one was female. The cause of the soft-tissue defects involved acute trauma and malignant melanom. All flaps survived and provided satisfactory coverage of the defect. Compared with the classic lateral supramalleolar flap, when the perforating branch is interrupted in its course, it is possible to elevate this subcutaneous fascial pedicled flap. The distally based flap with a compound pedicle which is continuous with a vascular axis and a band of subcutaneous fascial pedicle has long pedicle. This procedure is valuable for remote defect of the foot. It is believed that this flap is versatile and effective and is a good addition to the available techniques used by reconstructive surgeons for coverage of the foot and ankle.

• Archives of Reconstructive Microsurgery
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• v.13 no.1
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• pp.51-57
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• 2004

Introduction: To cover the exposed tendons and bones in the foot and hand which need coverage and abundant vascular flow, lateral arm flaps were transferred. Lateral arm flap is a thin and innervated fasciocutaneous flap with a lower lateral cutaneous nerve and posterior radial collateral artery. Materials and methods: From October 1992 through September 2003, we have performed 5 lateral arm flaps for reconstruction of the exposed achilles tendons in 2 cases and the exposed forearm extensors, 2nd to 5th metacarpal bones and scaphoid each 1 case. The causes were traffic accident in 2 cases and machinary injury in 3 cases. Age range was between 31 to 74 (average 50) and all male except 1. Posterior lateral collateral artery and venae comitantes were anastomosed by end to end in 3 cases and vena comitante in 2 cases. Lower lateral cutaneous nerve was anastomosed with a branch of superficial radial nerve in 2 cases. Results: The results were evaluated by survival of the flap, sensory discrimination, cosmesis and comfort in the activities of the daily living. All flaps were survived. Sensory recovery was graded as deep cutaneous pain sensibility in 2 cases. Cosmesis was moderately satisfied and comfort was good except 1 as moderate. Postoperative defatting procedure was done in 1 case and skin abrasion was occurred in 1 case. Conclusion: Lateral arm flap was suitable for coverage of the exposed achilles tendons and exposed forearm extensors, metacarpals and scaphoid in the wrist.

• Archives of Plastic Surgery
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• v.38 no.5
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• pp.663-668
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• 2011

Purpose: A modified free thenar flap was designed for coverage of volar finger defect with constant innervation using the palmar cutaneous branch of the median nerve. After clinical application of this flap, sensory results were evaluated in 6 cases. Methods: Patients were selected who have volar soft tissue defect with or without fingertip defect. The six cases of the innervated free thenar flap were performed since September 2009, and sensory outcomes were evaluated by the Semmes-Weinstein monofilament and two-point discriminator at four and half month after the surgery. Results: The Semmes-Weinstein Monofilament test revealed 3 cases showed 2.83, 1 case showed 3.61, 1 case showed 4.31 and 1 case showed 4.56. The static two-point discrimination test revealed 1 case showed 4 mm, 1 case showed 6 mm, 2 cases showed 9 mm, and 2 cases showed over 15 mm. The moving two-point discrimination test revealed 1 case showed 3 mm, 1 case showed 4 mm, 1 case showed 5 mm, 1 case showed 7 mm, and 2 cases showed over 15 mm. The donor sites showed no significant limitation of the thumb and neuroma formation. Conclusion: The innervated free thenar flap showed good sensory outcomes as a sensate free flap in a short time after surgery. It can be an option for coverage of volar finger defects that requires sensation.