• Magazine of the Korea Concrete Institute
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• v.7 no.6
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• pp.50-63
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• 1995

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.89-94
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• 1997

As the reinforced concrete structures are aged, repair and rehabilitation materials and techniques have ben developed. However, most of the repair materials and methods are imported from abroad and theoretical study and repairing techniques are also not well established yet. A specification for quality of repair materials should be established, in order to secure the stability and to improve the serviceability of the repaired structures. In this study, long term properties of repair materials such as thermal expansion coefficient, hardening shrinkage, creep, and chemical resistance have been tested. The material properties shows to be affected many actors such as curing period, temperatures, relative humidity, and etc. The repair material should be selected by considering the cause and shape of the defects, mix properties, workability, quality control of construction, and etc.

• Clinics in Shoulder and Elbow
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• v.19 no.1
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• pp.51-58
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• 2016

The arthroscopic rotator cuff repair is now considered a mainstream technique with highly satisfactory clinical results. However, concerns remain regarding healing failures for large and massive tears and high revision rate. In recent decades, various repair strategies and construct configurations have been developed for rotator cuff repair with the understanding that many factors contribute to the structural integrity of the repaired construct. The focus of biomechanical test in arthroscopic repair has been on increasing fixation strength and restoration of the footprint contact characteristics to provide early rehabilitation and improve healing. These include repaired rotator cuff tendon-footprint motion, increased tendon-footprint contact area and pressure, and tissue quality of tendon and bone. Recent studies have shown that a transosseous tunnel technique provides improved contact area and pressure between rotator cuff tendon and insertion footprint, and the technique of using double rows of suture anchors to recreate the native footprint attachment has been recently described. The transosseous equivalent suture bridge technique has the highest contact pressure and fixation force. In this review, the biomechanical tests about repair techniques of rotator cuff tear will be reviewed and discussed.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.861-872
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• 2021

An efficient cost management is important for the domestic social overhead capital(SOC) based on a long lifecycle after 30 years since completion. Maintenance in South Korea have had the restrictions of consistency and suitability of decision-making by the establishment of a budget plan based on the company estimate and repair and reinforcement methods determined by the inspection and diagnosis engineers' subjective determination for each facility. To resolve this issue, the Korea Institute of Civil Engineering and Building Technology is currently in development of a methodology to propose an optimum maintenance method according to the damage of components by artificial intelligence. This study has deduced the primary factors by analyzing information generated during bridge maintenance and management as a prior step for the development of technologies, and conducted a preliminary analysis to select the optimum artificial intelligence technology.

• Earthquakes and Structures
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• v.10 no.3
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• pp.613-628
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• 2016

The effectiveness of the use of modern repair schemes for the seismic retrofit of existing RC structures were assessed on a comparative experimental study of carbon fiber-reinforced polymer (CFRP) strips and sheets for the repair of reinforced concrete members of RC frames, damaged because of cyclic loading. Two virgin, single - story, one - bay, 1/3 - scale frame specimens were tested under cyclic horizontal loading, up to a drift level of 4%. Then, virgin specimens, B and F, respectively, were repaired and retested in the same way. One, specimen RB, was repaired with epoxy injections and CFRP strips and one, specimen RF, was repaired with epoxy injections and CFRP sheets. The two specimens are used to examine the differences between the structural behavior of frames repaired using CFRP strips and frames repaired using CFRP sheets. Both qualitative and quantitative conclusions, based on the observed maximum loads, loading and reloading stiffness, hysteretic energy absorption and failure mechanisms are presented and compared. The repaired frames recovered their strength, stiffness and energy dissipated reasonably. The use of CFRP sheets was found more effective than CFRP strips, due to the proper anchorage.

• Physical Therapy Korea
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• v.5 no.3
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• pp.34-41
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• 1998

Noninvasive low intensity ultrasound has been shown to be an effective means of accelerating bone fracture repair in both animal and clinical studies. The effects of ultrasound stimulation on bone repair after fibular osteotomy were assessed in a rabbit fibular fracture model. Bilateral closed fibular fractures were made in skeletally mature male White Japanese rabbits. In this study, 24 subjects were randomly divided into 2 groups: experimental group 1 (n=12), and experimental group 2 (n=12). Experimental group 1 received 0.875 MHz continuous ultrasound and Experimental group 2 was treated with 3 MHz continuous u1trasound. The ultrasound intensity was 50 $mW/cm^2$ and treatment time was 10 minutes for every session in both groups. In each rabbit, one fibula served as a control and the other was subjected to ultrasound treatment 5 times per week for 3 weeks. After 3 weeks, rabbits were sacrificed and the ratios of the area between the trabeculae and bone marrow of the fibulae were calculated. At the end of the experimental period, 14 of the 24 rabbits were excluded due to complications from surgery or inadequate fracture status for this study. There was no statistically significant difference in the trabeculae area between experimental leg and control leg in experimental group 1 and experimental group 2 (p>0.05). And there was also no statistic-statistically significant difference between experimental group 1 and experimental group 2 according to ultrasound treatment frequencies, 0.875 MHz and 3 MHz (p>0.05). These data suggest that in Japanese white rabbits, low intensity ultrasound stimulation does not facilitate fracture repair nor is there any difference in fracture repair results between ultrasound frequencies, 0.875 MHz and 3 MHz.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.3
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• pp.101-110
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• 2002

Most of the agricultural structures are in shortage of feasible facility management because these structures are small in size and spacially distributed in rural area. Inspection tools based on visual inspections are generally used for agricultural structures in most of the countries, including Korea. It is necessary to survey data of the irrigation structures to maintain records, and to develop the interface program by constructing database of inspection data. This study was conducted to develop a system for safe appraisal and repair works on agricultural irrigation structures. Repair and rehabilitation method can be chosen from an optimum viewpoint if the information between the method and life-cycle management cost of agricultural structures is constructed in the database. In this study, the system assisting onsite field investigation and determining the typical rehabilitation method of typical agricultural structural problems such as fractures and cracks of members was developed.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.458-463
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• 2000

Recently, there are increasing much concerns about repair and rehabilitation works for aged Concrete Structures which had been constructed on around the 1970's for rapid economic growth in Korea. In particular, it is believed that there are many aged concrete slabs for Highway bridges in these days. Thus new construction method of concrete slabs are strongly needed to minimize the traffic congestion during the repair works. The objective of this research is to develop the new constructional method of concrete slab in bridge structure, which can contribute to minimize the traffic congestion to be occurred during the repair and rehabilitation works of aged concrete slab, and can also assure the reliable quality through the minimization of in-situ works at the site. I-beams with punch holes will be manufactured in accordance with the specification in the factory, and will be preassembled into the panel. After erecting the preassembled panels in the site, concrete will be poured into the slab panel. This research is to investigate physical properties of I-Beam with punch holes itself, and then to investigate structural properties of assembled I-Beam panels through static and fatigue test, of which result can be utilized for the development of the new constructional method for concrete slab in bridge structure.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.6
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• pp.731-741
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• 2013

CCTV inspection method has been used in Korea for more than 20 years, but there is no proper assessment system for sewer failure severity that considers the domestic circumstances. This study classified the defects caused by the overburden load of reinforced concrete sewer pipes depending on severity and developed defect code by analyzing the domestic CCTV inspection videos. The defect score was assigned to each defect code, and it was classified into 5 grades for the decision-making of repair and rehabilitation. The result of this study is expected to be useful for domestic CCTV inspectors to assess the sewer condition and helpful for managers to make a decision of repair and rehabilitation.

• The Korean Journal of Pain
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• v.33 no.4
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• pp.344-351
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• 2020

Background: The effects of far-infrared radiation (FIR) on the treatment of rotator cuff diseases remains unknown. We evaluated the safety and efficacy of FIR after arthroscopic rotator cuff repair with regard to postoperative pain and healing. Methods: This prospective randomized comparative study included 38 patients who underwent arthroscopic rotator cuff repair due to a medium-sized tear. Patients were randomly divided into the FIR or control group (n = 19 per group). In the FIR group, FIR with an FIR radiator started 1 week postoperatively for 30 minutes per session twice daily. It lasted until abduction brace weaning at 5 weeks postoperatively. We assessed pain using a pain visual analogue scale (pVAS) and measured the range of motion (ROM) of the shoulder at 5 weeks, and 3 and 6 months, postoperatively. The anatomical outcome was evaluated using magnetic resonance imaging at 6 months postoperatively. Results: At 5 weeks postoperatively, the average pVAS score was lower in the FIR group than in the control group (1.5 ± 0.8 vs. 2.7 ± 1.7; P = 0.019). At 3 months postoperatively, the average forward flexion was higher in the FIR group (151.6° ± 15.3° vs. 132.9° ± 27.8°; P = 0.045), but there was no significant difference at 6 months postoperatively. There was no significant difference in healing failure between the groups (P = 0.999). Conclusions: FIR after arthroscopic rotator cuff repair could be an effective and safe procedure to reduce postoperative pain, thereby facilitating rehabilitation and better ROM in the early postoperative period.