• Steel and Composite Structures
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• v.16 no.6
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• pp.703-718
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• 2014

The initial clamping forces of high strength bolts subjected to different faying surface conditions drop within 500 hours regardless of loading, any other external force or loosening of the nut. This study develops a mathematical model for relaxation confined to creep on a coated faying surface after initial clamping. The quantitative model for estimating relaxation was derived from a regression analysis for the relation between the creep strain of the coated surface and the elapsed time for 744 hours. This study establishes an expected model for estimating the relaxation of bolted joints with diverse coated surfaces. The candidate bolts are dacro-coated tension control bolts, ASTM A490 bolt, and plain tension control bolts. The test parameters were coating thickness, species of coating. As for 96, 128, 168, and $226{\mu}m$ thick inorganic zinc, when the coating thickness was increased, relaxation after the initial clamping rose to a much higher range from 10% to 18% due to creep of the coating. The amount of relaxation up to 7 days exceeded 85% of the entire relaxation. From this result, the equation for creep strain can be derived from a statistical regression analysis. Based on the acquired creep behavior, it is expected that the clamping force reflecting relaxation after the elapse of constant time can be calculated from the initial clamping force. The manufacturer's recommendation of inorganic zinc on faying surface as $75{\mu}m$, appears to be reasonable.

• Advances in concrete construction
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• v.2 no.4
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• pp.249-259
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• 2014

Mortar is a masonry product which is matrix of concrete. It consists of binder and fine aggregate and moreover, it is an essential associate in any reinforced structural construction. The strength of mortar is a special concern to the engineer because mortar is responsible to give protection in the outer part of the structure as well as at a brick joint in masonry wall system. The purpose of this research is to investigate the compressive strength and tensile strength of mortar, which are important mechanical properties, by replacing the cement and sand by stone dust. Moreover, to minimize the increasing demand of cement and sand, checking of appropriateness of stone dust as a construction material is necessary to ensure both solid waste minimization and recovery by exchanging stone dust with cement and sand. Stone dust passing by No. 200 sieve, is used as cement replacing material and retained by No. 100 sieve is used for sand replacement. Sand was replaced by stone dust of 15%, 20%, 25%, 30%, 35%, 40%, 45% and 50% by weight of sand while cement was replaced by stone dust of 3%, 5%, and 7% by weight of cement. Test result indicates that, compressive strength of specimen mix with 35% of sand replacing stone dust and 3% of cement replacing stone dust increases 21.33% and 22.76% respectively than the normal mortar specimen at 7 and 28 days while for tensile it increases up to 13.47%. At the end, optimum dose was selected and crack analysis as well as discussion also included.

• Steel and Composite Structures
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• v.28 no.3
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• pp.363-380
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• 2018

This paper presented an integral design procedure for demountable bolted composite frames with semi-rigid joints. Moment-rotation relationships of beam-to-column joints were predicted with analytical models aiming to provide accurate and reliable analytical solutions. Among this, initial stiffness of beam-to-column joints was derived on the basis of Timoshenko's plate theory, and moment capacity was derived in accordance with Eurocodes. The predictions were validated with relevant test results prior to further applications. Frame analysis was conducted by using Abaqus software with material and geometrical nonlinearity considered. Variable lateral loads incorporating wind actions and earthquake actions in accordance with Australian Standards were adopted to evaluate the flexural behaviour of the composite frames. Strength and serviceability limit state criteria were utilized to verify configurations of designed models. A wide range of frames with the varied number of storeys and bays were thereafter programmed to ascertain bending moment envelopes under various load combinations. The analytical results suggest that the proposed approach is capable of predicting the moment-rotation performance of the semi-rigid joints reasonably well. Outcomes of the frame analysis indicate that the load combination with dead loads and live loads only leads to maximum sagging and hogging moment magnitudes in beams. As for lateral loads, wind actions are more crucial to dominate the design of the demountable composite frames than earthquake actions. No hogging moment reversal is expected in the composite beams given that the frames are designed properly. The proposed analysis procedure is demonstrated to be a simple and efficient method, which can be applied into engineering practice.

• Journal of the Korean Arthroscopy Society
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• v.1 no.1
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• pp.132-138
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• 1997

The purpose of this study is to compare the results between conventional and accelerated rehabilitation program following ACL reconstruction using bone-patellar tendon-bone. Conventional rehabilitation focused on protecting the new ligament by blocking terminal extension and avoiding active quadriceps function in the terminal degrees of extension. But there is current trend toward early postoperative mobilization and intensive. so called 'accelerated', rehabilitation stressing hyperextension of the knee. The results of intraarticular ACL reconstruction with conventional and accelerated rehabilitation were prospectively compared for one year postoperatively in a series of 27 patients. Range of motion and thigh circumference were checked preoperatively, and weekly up to 8 weeks, 3 months. 6 months, and 1 year postoperatively. Stress radiologic test, KT-1000 arthrometer. Cybex II dynamometer were checked in preoperatively, and 3 months, 6 months, and 1 year postoperatively. There were no differences of objective stability and restoration of muscle power. But the accelerated group had a low incidence of extension loss. excellent range of motion, and less difference of thigh circumference. We concluded that accelerated rehabilitation program is recommendable due to superiority in terms of range of motion, especially less extension loss without increasing laxity of knee joint.

• Journal of the Korean Arthroscopy Society
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• v.2 no.2
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• pp.129-134
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• 1998

The arthroscopic ACL reconstruction using the bone-patellar tendon-bone has been considered as the gold standard in the treatment of the ACL insufficiency. There are many reports about the good functional outcome and the restored stability of the knee joint. But there are a few reports showing whether this surgery has good results in the patients' satisfaction. The purpose of this study is to evaluate the patients' satisfaction in this surgery. Authors analysed 32 cases who had taken the ACL reconstruction from Jannuary, 1989 to June, 1997. The average follow-up was 40 months. At the last follow-up, 32 patients reported the patients' satisfaction degrees(four degrees; very satisfied, generally satisfied, improved, no change or aggravated), KT-1000 arthrometer test, Vastus atrophy(thigh circumference), and three kinds of the knee scores(Lysholm, HSS, IKDC). Among the 32 cases, 12 cases (37.5%) were very satisfied, 17 cases(53.1%) were generally satisfied and 3 cases(9.4%) were improved. No case showed no change or aggravated. The satisfaction degree in this surgery had little relation with the age, operation time, follow-up period, combination of meniscectomy, but had significant relations with anteroposterior stability evaluated by KT-1000, thigh circumference measurements and the functional scoring of the knee(Lysholm, HSS, IKDC scores).

• Journal of Korean Academy of Nursing
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• v.50 no.2
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• pp.271-285
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• 2020

Purpose: This study examined the effects of a physical activity promoting program based on the Information-Motivation-Behavioral Skills (IMB) model on physical activity and health outcomes among obese older adults with knee osteoarthritis. Methods: This study utilized a randomized controlled trial with a convenience sample of 75 obese older adults with knee osteoarthritis in a university hospital. The older adults in the intervention group participated in a 12-week program involving weekly group sessions and monitoring calls with education booklets and video clips for exercise dances, while those in the control group received an usual care. Outcomes were measured using self-report questionnaires, anthropometrics, and blood analyses. The intervention effects were analyzed using Mann-Whitney U test and ANCOVA. Results: The mean age of participants was 74.9 years with 84.0% women. The intervention group at 12 weeks showed significantly greater improvements in self-efficacy for physical activity (F=81.92, p<.001), physical activity amounts (Z=-2.21, p=.044), knee joint function (F=15.88, p<.001), and health-related quality of life (F=14.89, p<.001) compared to the control group. Among obese-metabolic outcomes, the intervention group at 12 weeks showed a significant decrease in visceral fat mass (F=7.57, p=.008) and improvement in high-density level cholesterol (F=9.51, p=.003) compared to the control group. Conclusion: Study findings support the need for an IMB based physical activity program for promoting physical activity, knee function and health outcomes in obese older adults with knee osteoarthritis. Longitudinal studies are warranted to confirm the persistence of obese-metabolic effects in clinical settings.

• Journal of Korean Academy of Nursing
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• v.50 no.2
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• pp.286-297
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• 2020

Purpose: This study aimed to identify the effects of myofascial pain syndrome on shoulder pain, range of motion, and body composition around the shoulder in middle-aged women. Methods: A total of 72 women participated in the randomized controlled trial. The subjects were grouped into an experimental group (n=39) and a control group (n=33). The experimental group received a resistance exercise program using an elastic band for 8 weeks, 3 days a week. The control group followed a normal daily for 8 weeks. Measurements were conducted three times; before the experimental treatment (pre-test), the 2nd and 8th weeks after treatment. Results: Regarding the general characteristics and homogeneity of the dependent variables, there were no significant differences between the two groups, except for the thickness of the left and right muscles and the left fat. After treatment, shoulder pain was significantly different between the two groups (F=18.54, p<.001) and the range of shoulder motion was significantly different (left, F=86.70, p<.001; right, F=98.66, p<.001). Furthermore, there were a significant differences in the thickness of muscles between the two groups (left, F=40.20, p<.001; right, F=29.57, p<.001); however, the thickness of fat was not significantly different. Conclusion: The resistance exercise program reduces shoulder pain and improves the range of motion of the shoulder joint and increases muscle mass on around the shoulder. It suggests to conduct a study to confirm the long-term exercise effect.

• Journal of Korean Neurosurgical Society
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• v.59 no.4
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• pp.374-378
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• 2016

Objective : A modified surgical technique of posterior cervical foramintomy called posterior cervical inclinatory foraminotomy (PCIF) was introduced in previous preliminary article. PCIF allows better preservation of facet joint and capsule than conventional techniques. The authors conducted a study to investigate long-term outcomes of PCIF. Methods : We retrospectively reviewed demographic, radiologic, and clinical data from the patients who underwent PCIFs at our institution. Criteria included a minimum of 48 month follow-up and PCIFs for patients with radiculopathy from foraminal stenosis (C2-T1; single or multilevel) with persistent or recurrent root symptoms despite conservative treatment for more than 3 months. Patients who had undergone previous cervical operation were excluded. The visual analogue scale (VAS) score was used for clinical follow-up, and radiologic follow-up was performed to compare the changes of cervical sagittal alignment, focal angle and disc-space height of treated segment. Results : The PCIFs were performed between April 2007 and March 2011 on 46 patients (32 males and 14 females) with a total of 73 levels affected. The average duration of follow-up was 74.4 months. Improvements in radiculopathic pain were seen in 39 patients (84.7%), and VAS score decreased from $6.82{\pm}1.9$ to $2.19{\pm}1.9$. Posterior neck pain also improved in 25 patients (71.4%) among 35 patients, and VAS score decreased from $4.97{\pm}2.0$ to $2.71{\pm}1.9$. The mean disc-space heights of treated segment were $5.41{\pm}1.03mm$ preoperatively and decreased to $5.17{\pm}1.12mm$ postoperatively. No statistically significant changes in cervical sagittal alignment, focal angle were seen during the follow-up period (Cox proportional hazards analysis and Student t-test, p>0.05). Conclusion : The PCIF is highly effective in treating patients with cervical spondylotic radiculopathy, leading to long-lasting relief in pain. Long-term radiologic follow-up showed no significant spinal angular imbalance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.7-14
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• 2002

In this study, a stress analysis is made fur an ankle foot orthosis (AFO) in the view point of structural stability. The investigated AFO is a solid and standard type. To analyze the stress distribution on the neck of AFO, the maximum AFO angular translation data is obtained by gait analysis. The material test of polypropylene is made to obtain the mechanical properties of AFO. The maximum dorsiflexion appears at the midstance in the gait analysis. The experimental angular translation at the top of AFO is about 10.3$^{\circ}$ at mid stance. Three models of AFO with different width of neck are made and analyzed with ABAQUS 6.1. The stress levels and distributions of 3 different width(W$_1$, W$_2$=0.85W$_1$, W$_3$=0.60W$_1$) AFO are investigated. As a result, the standard type(W$_1$) appears to the maximum stresses at the medial edge of cutout area surrounding ankle joint. The maximum stresses of the narrower type(W$_2$) are occured on medial edge and center of ankle. The narrowest type(W$_3$) appears to the maximum stresses at center of ankle. The maximum stresses become smaller as ankle width of AFO is narrower.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.1
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• pp.1-10
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• 1999

There is no official landscape architectural organization in the current government organization in Korea. Therefore, it is necessary to establish the landscape architectural organization which will carry out the works of the special landscape architectural interest and create the new services with other interested government offices. The contents of the study are as follows; 1. A legal basis for the establishment of the landscape architectural organization is the demand for the introduction of the landscape architectural organization which has 5 types(urban planning, architecture, land register, land surveying, civil work) of the special groups to official organization by changing the 1 article of the Official Appointment Regulations. 2. Theories of law of equality for everyone(the Constitution of Korea : §11(1)), the rights of having pleasant residential life(the Constitution of Korea : §35(3)) and the national duty of employment increase(the Constitution of Korea : §32(1)) are reviewed to provide the legal reason of establishing the landscape architectural organization. 3. With the addition of new landscape architectural organization, it could expand the areas of landscape architects by adding of new landscape architectural subjects into official examinations for government employees. Also it is necessary to exempt the test for those who have licenses and to give additional points in evaluation their works at the end of year to the people who have licenses. 4. The reasons for the creation of new landscape architectural organization into the present official organization are acquired from the derivation of 23 present regulations referring to the landscape architects, the existence of the landscape architectural administrative departments belonging to the Metropolis of Seoul, and the favorable result of the questionnaire on the establishment of the new organization. Hereafter the lawyers should be cooperated with landscape architects to initiate the related principles of law, and it is necessary to analyze each text of the related laws in detail to establish the landscape architectural organization by means of the joint studies.