• The Korean Journal of Applied Statistics
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• v.28 no.2
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• pp.335-342
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• 2015

Joint hierarchical generalized linear models proposed by Molas et al. (2013) extend the simple longitudinal model into multiple models fitted jointly. It can easily handle the correlation of multivariate longitudinal data. In this paper, we apply this method to analyze KoGES cohort dataset. Fixed unknown parameters, random effects and variance components are estimated based on a standard framework of h-likelihood theory. Furthermore, based on the conditional Akaike information criterion the correlated covariance structure of random-effect model is selected rather than an independent structure.

• Journal of Welding and Joining
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• v.5 no.1
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• pp.57-63
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• 1987

A method which can be used for evaluating slag detachability is proposed in this study. The proposed method was intended to get an absolute value for slag detachability, to give consistent value for a given welded joint, and finally to be simple to test. With a test fig made in this study, an impact by dropping a steel ball (13Kg in weight) is applied on the back side of an as-welded plate having a slag layer on the weld bead. Such impact applied forces the slag to drop off from the bead surface. In order to make a quantitative evaluation the amount of slag removed was measured with increasing the number of drops. Using this method six kinds of fluxes were evaluated in terms of the effects of flux type, basicity and weding variables on the slag detachability. As an initial result of this test, it was found that welding heat input affects the detachability significantly. Most importantly the evaluation made using the presently proposed method gives the same order of ranking as that of the actual practice done by a welder.

• Steel and Composite Structures
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• v.1 no.2
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• pp.213-230
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• 2001

This paper presents a simplified approach for the design of semi-continuous composite beams in braced frames, where specific attention is given to the effect of joint rotational stiffness. A simple composite beam model is proposed incorporating the effects of semi-rigid end connections and the nonprismatic properties of a 'cracked' steel-concrete beam. This beam model is extended to a sub-frame in which the restraining effects from the adjoining members are considered. Parametric studies are performed on several sub-frame models and the results are used to show that it is possible to correlate the amount of moment redistribution of semi-continuous beam within the sub-frame using an equivalent stiffness of the connection. Deflection equations are derived for semi-continuous composite beams subjected to various loading and parametric studies on beam vibrations are conducted. The proposed method may be applied using a simple computer or spreadsheet program.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.767-770
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• 2006

To predict vibrational energy density of simple structural-acoustic coupled systems in medium-to-high frequency ranges, Power Flow Finite Element Method(PFFEM) is used, and PFFEM sofiware, PFADS has been developed for the vibration predictions and analysis of coupled system structures in medium-to-high frequency ranges. However, it needs to consider vibro-acoustic coupled analysis to get more accurate results. Prior to implement vibro-acoustic coupled analysis functions in PFADS, research on vibro-acoustic coupled analysis using PFFEH is performed for simple models. These predictions include the indirect transmission path associated, and also the direct transmission path, and the formulation is extended to structural system model by using appropriate modifications to structural-acoustic and acoustic-acoustic joint matrices. Concerning the waves in plate and acoustic, it is possible to calculate the structural-acoustic full matrix of a model using PFFEM, and the formulations developed are implemented for two rooms surrounded by plates.

• Journal of the Korean Society of Safety
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• v.31 no.2
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• pp.64-69
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• 2016

In this paper, structural analysis of High-Speed railway vertical tunnel structures was performed to verify the structural stability. The corrugated steel plate method was applied to the vertical tunnel structures for its simple construction method and low cost. The structural stability of Wall, Connection and Storage section was performed with LRFD and ASD design method at joint part, buckling, stress and plastic hinge. From the results, all of vertical tunnel structures shown the structural stability regardless of design method and structure types. So, the application of corrugated steel plate in vertical tunnel structures instead of cast-in-placed concrete was quite enough.

• Journal of Korean Foot and Ankle Society
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• v.13 no.1
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• pp.14-18
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• 2009

Purpose: We evaluated the results of treatment and clinical symptoms of 11 cases of synovial chondromatosis in the ankle joint. Material and Method: From February 2001 to May 2008, 11 cases with synovial chondromatosis involving ankle joint underwent surgical treatment. There were 5 males and 6 females. The average age at surgery was 51 years. The average follow-up period was 42 months. Duration from onset of symptom to treatment was 117 months. Chief complaints of patients, 9 cases were pain and 1 case was mass like lesion, 1 case was found on x-ray. Preoperatively, all cases were evaluated on simple x-ray, 4 cases on CT, 4 cases on MRI and 1 case on ultrasonogram. 10 cases underwent synovectomy and loose body removal. 5 cases of 10 cases underwent open synovectomy and loose body removal and arthrosocpic surgery. 4 cases of 10 cases underwent only open synovectomy and loose body removal and 1 case of 10 cases underwent only arthroscopic surgery. 1 case underwent tibiotalar arthrodesis. Results: The location of loose bodies was 7 cases on posterior and 4 cases on anterior and 4 case on lateral and 3 cases on multiple site. Postoperatively, all patients showed marked clinical improvement and had subjective satisfaction except reoperation 2 cases and arthrodesis 1 case. AOFAS score of all patients was average 82.2. Conclusion: Clinical results of the synovial chondromatosis of ankle joint were satisfactory. More accurate preoperative evaluation is required to achieve prevention of postoperative recurrence and better outcome.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.990-995
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• 1990

A minimum-time trajectory planning for two robot arms with designated paths and coordination is proposed. The problem considered in this paper is a subproblem of hierarchically decomposed trajectory planning approach for multiple robots : i) path planning, ii) coordination planning, iii) velocity planning. In coordination planning stage, coordination space, a specific form of configuration space, is constructed to determine collision region and collision-free region, and a collision-free coordination curve (CFCC) passing collision-free region is selected. In velocity planning stage, normal dynamic equations of the robots, described by joint angles, velocities and accelerations, are converted into simpler forms which are described by traveling distance along collision-free coordination curve. By utilizing maximum allowable torques and joint velocity limits, admissible range of velocity and acceleration along CFCC is derived, and a minimum-time velocity planning is calculated in phase plane. Also the planning algorithm itself is converted to simple numerical iterative calculation form based on the concept of neural optimization network, which gives a feasible approximate solution to this planning problem. To show the usefulness of proposed method, an example of trajectory planning for 2 SCARA type robots in common workspace is illustrated.

• Clinics in Shoulder and Elbow
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• v.1 no.2
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• pp.180-185
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• 1998

There has been considerable controversy as to the treatment method of dislocation of the acromioclavicular joint, so various operative treatment modalities have been suggested. We analyzed the results of 40 patients with acromio­clavicular dislocation, in whom twenty patients were treated by modified Phemister method and 20 patients by modified Weaver-Dunn method above follow-up two years. The purpose of this study was to compare the clinical results of two operative methods. According to Weitzman criteriae for clinical results, 12 cases were excellent, six cases good and two cases fair in modified Phemister method. But in modified Weaver-Dunn method, ten cases were excellent, eight cases good, one case fair and one case poor. In radiological result, coracoclavicular distance was measured at preoperative, postoperative and last follow-up period. The modified Phemister method was 6.lmm, 1.5mm and 2.4mm respectively, and the modified Weaver-Dunn method 7.8mm, 2.lmm and 2.5mm respectively. The complications were two cases of heterotopic ossification, one case of inadequate fixation and one case of K-wire breakage in modified Phemister method, and two cases of early fixation loss and one case of heterotopic ossification in modified Weaver-Dunn method. We obtained that the clinical, functional and radiological results showed no significant difference in two methods. The modified Phemister method was effective treatment for old patients in acute injuries due to short operation time and simple technique. The modified Weaver-Dunn method, as a reconstructive operation that reduces various complications for young and active male patients, was also good for getting the stability of coraco­clavicular ligament through clavicular bony union.

• Clinics in Shoulder and Elbow
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• v.13 no.2
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• pp.209-216
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• 2010

Purpose: The purpose of our study was to compare treatment results of two different surgical techniques for chronic acromioclavicular joint dislocations. Materials and Methods: Fifty consecutive patients diagnosed as chronic acromioclavicular joint dislocations between January 1997 and June 2009 were included in the study. Patients were randomized into two different groups. Patients in the first group (n=20) were treated using a modified Weaver and Dunn method using a simple coracoacromial ligament transfer method. Patients in the other group (n=30) were treated with acromial bone-block transfer containing coracoacromial ligament. Mean follow-up times for the two groups were 13.1 and 14.9 months, respectively. Results: At 1 year postoperatively, mean coracoclavicular distance, the VAS score and the ASES score for the Weaver-Dunn method group; for the bone block transfer method group were 3.8 mm (-3 to 6 mm), 3.5 (1.0 to 7.0) and 91.1 (81.66 to 95); 3 mm (-2 to 6 mm), 4.2 (1.0 to 7.5) and 79.6 (31.66 to 95). There were no significant differences in radiologic (p=0.377) and functional (p=0.093) results between the two groups. Failures in the former and latter group were, respectively, two and one. Conclusion: The bone block transfer method shows a tendency to maintain coracoclavicular distance and appeared to yield similar results as the modified Weaver Dunn method.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.803-806
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• 1997

In this paper, a force estimation method is proposed for the sensorless force control. For this, a disturbance observer is applied to each joint of an n degrees of freedom manipulator to obtain a simple equivalent robot dynamics(SERD) being represented as an n independent double integrator system. To estimate the output of disturbance observer in the absence of external force, the observer estimator is designed, where the uncertain parameters of the robot manipulator are adjusted by gradient method to minimize the output between the disturbance observer and the observer estimator. When the external force is exerted, the external force is estimated using the difference between the output of disturbance observer which include the external torque signal and that of observer estimator. And then, a force controller is designed for force feedback control employing the estimated force signal. To verify the effectiveness of the proposed force estimation method, several numerical examples are illustrated for the 2-axis planar type robot manipulator.