• The Korean Journal of Pain
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• v.33 no.3
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• pp.258-266
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• 2020

Background: The genicular nerve block (GNB) is demonstrated from several reports to alleviate pain and improve knee functionality in patients with chronic knee osteoarthritis (OA). Ultrasound (US)-guided GNB has been the most used imaging method. This study aimed to compare the effectiveness of US-guided versus blind GNB in the treatment of knee OA. Methods: This prospective, randomized clinical trial included patients with knee OA based on American College of Rheumatology diagnostic criteria. The patients were evaluated for clinical and dynamometer parameters at the baseline, 4 weeks after treatment, and 12 weeks after treatment. The patients underwent blind injection or US-guided injection. Results: When compared with the baseline, both groups showed significant improvement in pain, physical function, and quality of life parameters. Significant differences were observed between the groups for clinical parameters (30-second chair stand test, 6-minute walk test) in favor of the US-guided group. On the other hand, blind injection was more significantly effective on some parameters of the Nottingham Health Profile. There wasn't any significant improvement in isokinetic muscle strength for either group. Conclusions: This study demonstrated that both US-guided and blind GNB, in the treatment of knee OA, were effective in reducing symptoms and improving physical function. GNB wasn't an effective treatment for isokinetic muscle function. US-guided injections may yield more effective clinical results than blind injections.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.705-713
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• 2018

An automotive ball joint connects the suspension system to the steering system and helps to enable rotational and linear motion between the two elements for steering. This study examines a ball joint used in medium and large-sized pickup trucks. Ball joints consist of a stud, socket, bearing, and plug. The main structural performance metrics of ball joints are the pull-out strength and push-out strength. These structural parameters must meet certain criteria to avoid serious accidents. Test and simulation methods are used to investigate the design requirements, but tests are time-consuming and costly. In this study, we modeled ball joints in SolidWorks and performed a finite element analysis in Abaqus to predict structural performance. The analysis was used to obtain the structural performance required for the static analysis of a 2D axisymmetric model. The uncertainties in the manufacturing of the ball joint were assumed to be the manufacturing tolerances, and the dimensional design variables were identified through case studies. The manufacturing tolerances at each level were defined, and the results were compared with experimental results.

• Korean Journal of Applied Biomechanics
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• v.28 no.1
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• pp.19-27
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• 2018

Objective: This study aimed to analyze the effects of freezing of gait on spatiotemporal variables, ground reaction forces (GRFs), and joint moments during the sit-to-walk task at the preferred and maximum speeds in patients with Parkinson's disease (PD). Method: The subjects were classified by a neurologist into 12 freezers, 12 non-freezers, and 12 controls. Sit-to-walk parameters were measured during three repetitions of the task in a random order at the preferred and maximum possible speeds. Results: In the sit-to-walk task at the preferred speed, the freezers and non-freezers exhibited a higher peak anterior-posterior GRF (p<0.001) in the sit-to-stand phase and lower step velocity (p<0.001), step length (p<0.001), and peak anterior-posterior GRF (p<0.001) in the first-step phase than the controls. The freezers had higher peak anterior-posterior GRF (p<0.001) and peak moment of the hip joint (p=0.008) in the sit-to-stand phase than the non-freezers. In the sit-to-walk phase at the maximum speed, the freezers and non-freezers had lower peak moment of the hip joint (p=0.008) in the sit-to-stand phase than the controls. The freezers and non-freezers displayed lower step velocity (p<0.001) and peak anterior-posterior GRF (p<0.001) in the first-step phase than the controls. The freezers showed higher peak moments of the hip joint in the sit-to-stand phase than the non-freezers (p=0.008). Conclusion: The PD patients had reduced control ability in sit-to-stand motions for efficient performance of the sit-to-walk task and reduced performance in the sit-to-walk task. Furthermore, the freezers displayed reduced control ability in the sit-to-stand task. Finally, the PD patients exhibited a lower ability to control dynamic stability with changes in speed than the controls.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.5
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• pp.870-875
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• 2011

Arthritis of the knee is the most common type of joint inflammatory disorder and it is associated with pain and inflammation of the joint capsule. The aim of present study was to investigate the endogenous effect of low intensity laser acupuncture on collagen-induced arthritis in rats. Forty Sprague-Dawley rats were randomly divided into normal group, arthritis group, low laser group with 10 rats in each group. Arthritis in rats was induced by subcutaneous injection of type II collagen combined with complete Freund's adjuvant. Here we investigated the effects of low intensity laser therapy in experimentally induced rat knee arthritis. To evaluate preventive and therapeutic effects of low intensity laser acupuncture on collagen-induced arthritis rats. In collagen induced arthritic rats, there was significant increase in rat paw volume and decrease in body weight increment, whereas low intensity laser therapy groups, showed significant reduction in paw volume and normal gain in body weight. The altered biochemical parameters(blood urea, serum creatinine, total proteins and acute phase proteins) in the arthritic rats were significantly brought back to near normal by the low intensity laser therapy. Therefore, low intensity laser acupuncture may be a useful treatment in the prevention and treatment of collagen-induced arthritis.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.11
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• pp.753-763
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• 2015

This paper proposes a decentralized robust adaptive neural network control scheme using multiple radial basis function neural networks for electrically driven robot manipulators with bounded input voltages in the presence of uncertainties. The proposed controller considers both robot link dynamics and actuator dynamics. Practically, the controller gain coefficients applied at each joint may be nonlinear time-varying and the input voltage at each joint is saturated. The proposed robot controller overcomes the various uncertainties and the input voltage saturation problem. The proposed controller does not require any robot and actuator parameters. The adaptation laws of the proposed controller are derived by using the Lyapunov stability analysis and the stability of the closed-loop control system is guaranteed. The validity and robustness of the proposed control scheme are verified through simulation results.

• Journal of Welding and Joining
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• v.35 no.2
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• pp.13-22
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• 2017

In laser full penetration welding process, full penetration hole(FPH) is formed as a result of force balance between the vapor pressure and the surface tension of the surrounding molten metal. In this work, a three-dimensional numerical model based on a conserved-mass level-set method is developed to simulate the transport phenomena during laser full penetration welding process, including full penetration keyhole dynamics. Ray trancing model is applied to simulate multi-reflection phenomena in the keyhole wall. The ghost fluid method and continuum method are used to deal with liquid/vapor interface and solid/liquid interface. The effects of processing parameters including laser power and scanning speed on the resultant full penetration hole diameter, laser energy distribution and energy absorption efficiency are studied. The model is validated against experimental results. The diameter of full penetration hole calculated by the simulation model agrees well with the coaxial images captured during laser welding of thin stainless steel plates. Numerical simulation results show that increase of laser power and decrease of welding speed can enlarge the full penetration hole, which decreases laser energy efficiency.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.10
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• pp.1417-1424
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• 2011

This study was conducted to assess the relation between threonine (Thr) oxidation rate and threonine efficiency on rat and chicken fed with graded levels of protein and threonine. The increase in threonine content from 0.28 to 0.72% in a diet containing 12.0% crude protein (CP) caused a gradual increase in threonine dehydrogenase (TDG) activity in rat liver. Similar, but more pronounced results were observed after 18.0% CP in the diet. Both protein levels in combination with the highest level of threonine supplementation increased liver TDG activity significantly, indicating enhanced threonine catabolism. Parameters of efficiency of threonine utilization calculated from parallel nitrogen balance studies decreased significantly and indicated threonine oversupply after a maximum of threonine supplementation. At the lower levels of threonine addition the efficiency of threonine utilization was not significantly changed. In the chicken liver up to 0.60% true digestible threonine (dThr) in the 18.5% CP diet produced no effect on the TDG activity. However, TDG activity in the liver was elevated by the diet containing 22.5% CP (0.60% dThr) and the efficiency of threonine utilization decreased, indicating the end of threonine limiting range. In conclusion, the in vitro TDG activity in the liver of rat and growing chicken has an indicator function for the dietary supply of threonine.

• Korean Journal of Computational Design and Engineering
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• v.19 no.4
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• pp.356-367
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• 2014

A robotic sapatial augmented reality (RSAR) system, which combines robotic components with projector-based AR technique, is unique in its ability to expand the user interaction area by dynamically changing the position and orientation of a projector-camera unit (PCU). For a moving PCU mounted on a conventional robotic device, we can compute its extrinsic parameters using a robot kinematics method assuming a link and joint geometry is available. In a RSAR system based on user-created robot (UCR), however, it is difficult to calibrate or measure the geometric configuration, which limits to apply a conventional kinematics method. In this paper, we propose a data-driven kinematics control method for a UCR-based RSAR system. The proposed method utilized a pre-sampled data set of camera calibration acquired at sufficient instances of kinematics configurations in fixed joint domains. Then, the sampled set is compactly represented as a set of B-spline surfaces. The proposed method have merits in two folds. First, it does not require any kinematics model such as a link length or joint orientation. Secondly, the computation is simple since it just evaluates a several polynomials rather than relying on Jacobian computation. We describe the proposed method and demonstrates the results for an experimental RSAR system with a PCU on a simple pan-tilt arm.

• Journal of Welding and Joining
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• v.30 no.6
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• pp.15-20
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• 2012

Brazing technology has been widely used among bonding technologies because it enables to bond various metals, even ceramics, dissimilar metals, and give higher bonding strength, cost down, automation, etc. However, there are many parameters to achieve optimal brazing joint such as brazing alloys, brazing atmospheres, designs and brazing methods, etc. The brazing parameters affect seriously on the characteristic of final brazing products. Stainless steel is broadly used in high temperature applications, chemical industry, heat exchangers, muffler of vehicles, and so on. Accordingly, in this article, brazing alloys, forms of brazing alloys, brazing methods and atmospheres for stainless steel were described.

• Tuberculosis and Respiratory Diseases
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• v.40 no.6
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• pp.683-693
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• 1993

Background: During movement the major inputs to nervous system come from firstly the muscle and joint to maintain posture and motion and secondly the chemoreceptors and baroreceptors to adjust the cardiovascular and respiratory function. Their complex relationships are generally studied for many years but the direct relation between the joint and respiratory system is not studied thoroughly until now. So this experiment was performed to determine whether the natural movement of knee joint can cause the enhancement of respiratory function by observation of the changes of respiratory rate, phrenic nerve activity and inspiratory neuron activity during the stimulation of knee joint in cat anesthetized with $\alpha$-chloralose. Method: Twenty six male adult cats were used and the extracelluar recording using bipolar platinum electrode and carbon filament electrode was done to record the changes in the activities of phrenic nerve and inspiratory neuron movement of knee joint, injection of chemicals into the joint cavity and electrical stimulation of articular nerve were done. Results: The 60 Hz. could not but 120 Hz. flexion-extension movement of knee joint increased respiratory rate(R.R.), tidal neural activity(TNA) and minute neural activity(MNA). Intra-articular injection of lactate could not increase R.R. but significantly increase TNA and MNA which represented the enhanced respiratory function. Injection of potassium chloride showed similar effects with the case of lactate but the duration of effect was shorter. The electrical stimulation of medial articular nerve with IV strength which could activate only group I and II afferents showed increased TNA and MNA during stimulation but 20 V stimulation which could activate all the afferents increased all the respiratory parameters. The changes of inspiratory neuron activity by knee joint stimulation was similar to that of phrenic nerve. Conclusion: The respiratory center could be directly stimulated by the activation of group I and II articular afferents and it seemed that the magnitude of the respiratory center enhancement is proportional to the amount of sensory information from the knee joint. These facts might suggest that the respiratory function could be enhanced even by the normal movement of knee joint.