• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.275-278
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• 1987

In this paper, a programming system for SCARA-type robots is designed, consisting of robot language, computational facilities and programming tools for handling interconnection environments. In designing the robot language, CLRC(C Library for Robot Control) is introduced, using the general-purpose language 'C' as base programming language. Also the motion primitives for Continuous Path control as well as Point-To-Point motion arc included. By means of frame and homogeneous transformations the system is capable of applying the SCARA-type robot efficiently and easily for any given task.

• Advances in aircraft and spacecraft science
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• v.5 no.1
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• pp.73-105
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• 2018

A particular type of constant speed helical trajectory, with variable ascension rate, is proposed. Such trajectories are candidates of choice as motion primitives in automatic airplane trajectory planning; they can also be used by airplanes taking off or landing in limited space. The equations of motion for airplanes flying on such trajectories are exactly solvable. Their solution is presented, together with an analysis of the restrictions imposed on the geometrical parameters of the helical paths by the dynamical abilities of an airplane. The physical quantities taken into account are the airplane load factor, its lift coefficient, and the thrust its engines can produce. Formulas are provided for determining all the parameters of trajectories that would be flyable by a particular airplane, the final altitude reached, and the duration of the trajectory. It is shown how to construct speed interval tables, which would appreciably reduce the calculations to be done on board the airplane. Trajectories are characterized by their angle of inclination, their radius, and the rate of change of their inclination. Sample calculations are shown for the Cessna 182, a Silver Fox like unmanned aerial vehicle, and the F-16 Fighting Falcon.

• The Journal of Korea Robotics Society
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• v.2 no.3
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• pp.234-241
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• 2007

Effective tools which can alleviate the complexity and computational load problem in collision-free motion planning for multi-agent system have steadily been demanded in robotics field. To reduce the complexity, the extended collision map (ECM) which adopts decoupled approach and prioritization is already proposed. In ECM, the collision regions which represent the potential collision of robots are calculated using the computational power; the complexity problem is not resolved completely. In this paper, we propose a mathematical analysis of the extended collision map; as a result, we formulate the collision region as an equation with 5-8 variables. For mathematical analysis, we introduce realistic assumptions as follows; the path of each robot can be approximated to a straight line or an arc and every robot moves with uniform velocity or constant acceleration near the intersection between paths. Our result reduces the computational complexity in comparison with the previous result without losing optimality, because we use simple but exact equations of the collision regions. This result can be widely applicable to coordinated multi-agent motion planning.

• Hip & pelvis
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• v.35 no.4
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• pp.268-276
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• 2023

Purpose: Resection remains the most reliable treatment for established heterotopic ossification, despite questions regarding its effectiveness due to the potential for complications. This study evaluated the clinical outcomes and complications of neurogenic heterotopic ossification (NHO) resection in stroke patients' ankylosed hips. Materials and Methods: We retrospectively analyzed nine hip NHO resections performed on seven patients from 2010 to 2018. The pre- and postoperative range of motion of the operated hip were compared. Analysis of postoperative complications, including infection, recurrence, iatrogenic fracture, and neurovascular injury was performed. Results: The mean operative time was 132.78±21.08 minutes, with a mean hemoglobin drop of 3.06±0.82 g/dL within the first postoperative week. The mean duration of postoperative follow-up was 52.08±28.72 months for all patients. Postoperative range of motion showed improvement from preoperative. Flexion and external rotation (mean, 58.89±30.60° and 16.67±18.03°, respectively) showed the greatest gain of motion of the operated hip joint. Postoperative infections resolved in two cases through surgical debridement, and one case required conversion to total hip arthroplasty due to instability. There were no recurrences, iatrogenic fractures, or neurovascular injuries. Conclusion: Resection is a beneficial intervention for restoring the functional range of motion of the hip in order to improve the quality of life for patients with NHO and neurological disorders. We recommend performance of a minimal resection to achieve a targeted functional arc of motion in order to minimize the risk of postoperative complications.

• Journal of Navigation and Port Research
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• v.40 no.6
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• pp.361-368
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• 2016

A ship's rolling motion can make crew and passengers sick and/or apply forces to the structure that cause damage.. Therefore bilge keels are equipped in most ships for anti-rolling. In special cases, anti-rolling tanks (ARTs), fin stabilizers, or gyroscopes can be installed. However, ARTs require a large area to install, and fin stabilizers and gyroscopes are costly to install and expensive to operate. This paper suggests a Anti-rolling pendulum (ARP) to reduce roll motion. ARPs acts like ARTs. However, the ARP has a circular shaped guidance arc instead of the string or wire of a simple pendulum. The device suggested has about 1/ 8 the weight and 1/ 6 the volume of a ART and is more effective. This study derives the nonlinear and linear differential equations of system motion.

• Tribology and Lubricants
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• v.36 no.2
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• pp.64-67
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• 2020

In the conventional gerotor design, the circular arc tooth of the outer rotor is first introduced, and then the inner rotor profile is generated by simulating the outer rotor motion while the inner rotor is fixed. The profile generation of tooth meshing exhibits relativity; therefore, the outer rotor profile can be generated by the movement of the inner rotor. In this study, we propose the design of a gerotor with a pin-tooth inner rotor. First, the pin-tooth inner rotor is devised, and then the outer rotor profile is generated. The profile of the inner rotor is simply composed of equally arranged pins along a circle. The root of the inner rotor is designed as a conjugated arc of two pins. The trajectory of the pin center is obtained by the inner rotor operation, and then the outer rotor profile is determined as a parallel curve of the trajectory. In this gerotor design, the inner rotor has a simple configuration, and contact occurs between the pin parts of the inner rotor and the whole profile of the outer rotor. This affects the material selection and machining process. The pin tooth can be used to design the outer and inner rotors, enabling a double gerotor mechanism corresponding to a planetary gear system.

• Geomechanics and Engineering
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• v.36 no.3
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• pp.303-316
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• 2024

Seismic records are composed of mainshock and a series of aftershocks which often result in the incremental damage to underground structures and bring great challenges to the rescue of post-disaster and the repair of post-earthquake. In this paper, the repetition method was used to construct the mainshock-aftershocks sequence which was used as the input ground motion for the analysis of dynamic time history. Based on the Daikai station, the two-dimensional finite element model of soil-station was established to explore the failure process of station under different seismic precautionary intensities, and the concept of incremental damage of station was introduced to quantitatively analyze the damage condition of structure under the action of mainshock and two aftershocks. An arc rubber bearing was proposed for the shock absorption. With the arc rubber bearing, the mode of the traditional column end connection was changed from "fixed connection" to "hinged joint", and the ductility of the structure was significantly improved. The results show that the damage condition of the subway station is closely related to the magnitude of the mainshock. When the magnitude of the mainshock is low, the incremental damage to the structure caused by the subsequent aftershocks is little. When the magnitude of the mainshock is high, the subsequent aftershocks will cause serious incremental damage to the structure, and may even lead to the collapse of the station. The arc rubber bearing can reduce the damage to the station. The results can offer a reference for the seismic design of subway stations under the action of mainshock-aftershocks.

• Archives of Plastic Surgery
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• v.45 no.4
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• pp.351-356
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• 2018

Background Mallet fracture can easily occur during sports activities or in daily life; however, the principles and methods of treatment for such fractures remain debated. Among the surgical treatments, various methods of closed reduction have been proposed. We treated patients with the extension block method (EBM) and the direct pinning method (DPM), and then compared the results. We assessed differences in range of motion and measurements of finger movement after surgery. Methods A total of 41 patients who underwent surgery from August 2013 to September 2015 were evaluated retrospectively. Among them, 21 patients were treated with the EBM and 20 patients were treated with the DPM. We then compared extensor lag, range of motion, and outcomes according to Crawford's criteria between before surgery and at 6 to 8 months postoperatively. Results The postoperative extensor lag improvement was $4.28^{\circ}$ and $10.73^{\circ}$, and the postoperative arc of motion was $55.76^{\circ}$ and $61.17^{\circ}$ in the EBM and DPM groups, respectively. The Crawford assessment showed no statistically significant difference between the groups, although the score in the DPM group was higher than that in the EBM group (3.5 vs. 3.1). Conclusions As closed reduction methods for the treatment of mallet fracture, both the EBM and DPM showed good results. However, the DPM proved to be superior to the EBM in that it produced greater improvements in extensor lag and range of motion.

• Journal of the Korean Arthroscopy Society
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• v.1 no.1
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• pp.1-8
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• 1997

The anterior cruciate ligament(ACL) is, perhaps, the most intriguing component of the knee joint. Initially referred to crucial ligament because of the cruciate or crossed arrangement or the anterior and posterior ligaments within the knee. the irony or the ACL being crucial to the well-being or the joint has only recently appreciated. The anterior cruciate ligament of human knee joint is a complex structure and its orientation, construct and biology arc directly related to the knee function as a constraint of knee joint motion. In addition to its functional role as a static stabilizer or the knee. the ACL has a unique neurovascular system. The vascular anatomy of the ACL plays a crucial role in the repair and reconstruction of the ligament, and the neuroreceptors found in its substance suggest a possible proprioceptive role for the ligament. The structural complexity of the ACL allows the ligament to function through the normal range of motion as a static stabilizer or the knee. hut it also makes the exact duplication of this structure very difficult. A comprehensive knowledge or the anatomy of the ACL can provide the orthopedic surgeon with a blueprint for the idealized repair and reconstruction of this most complex structure.

• Clinics in Shoulder and Elbow
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• v.12 no.1
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• pp.67-75
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• 2009

Purpose: This study evaluated the clinical outcomes of debridement arthroplasty using the posteromedial approach in elbow joints with pain and bony limitation of motion. Materials and Methods: This study involved 16 elbows in 16 patients with pain and bony limitation of motion, which were treated by debridement arthroplasty using the posteromedial approach from March 2005 to March 2008. The mean follow up period was 27.6 (13~52) months. The clinical outcomes were analyzed using the Visual Analogue Scale(VAS) for pain scale, the preoperative and postoperative range of motion and the Mayo Elbow Performance Scores(MEPS). Results: The VAS was decreased significantly from a preoperative mean of 4.5 to a postoperative mean 1.1 (p<0.001). The average arc of motion improved significantly from $61.6 (0~90)^{\circ}$ preoperatively to $109.4 (80-120)^{\circ}$ postoperatively (p<0.001). The MEPS also improved significantly from 59.4 to 85.6 postoperatively (p<0.001). There were no complications, such as hematoma and elbow instability. Conclusion: Debridement arthroplasty using the posteromedial approach is a useful surgical procedure in the elbow joint with pain and bony limitation of motion, where all compartments can be debrided, the ulnar nerve can be manipulated easily and damage to the medial collateral ligament can be minimized.