• Journal of Institute of Control, Robotics and Systems
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• v.21 no.8
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• pp.753-757
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• 2015

This paper introduces an experimental rescue robot, HUBO T-100 and presents the optimal motion control method. The objective of the rescue robot is to extract patients or wounded soldiers in the battlefield and hazardous environments. Another mission is to dispose and transport an explosive ordnance to safe places. To execute these missions, the upper body of the rescue robot is humanoid in form to execute various kinds of tasks. The lower body features a hybrid tracked/legged design, which allows for a variety of mode of locomotion, depending on terrain conditions in order to increase traversability. The weight lifting motion is one of the most important task for performing rescue related missions because the robot must lift an object or impaired person lying on the ground for transferring. Here, dynamics based motion optimization is employed to minimize joint torques while maintaining stability simultaneously. Physical experiments with a real humanoid robot, HUBO T-100, are presented to verify the proposed method.

• The Journal of the Korean bone and joint tumor society
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• v.13 no.2
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• pp.173-179
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• 2007

Brown tumor is tumor like lesion resulted from hyperparathyroidism, and it has been rarely reported recently. We evaluated a 29-year-old woman who had brown tumor on proximal humerus caused by primary hyperparathyroidism. She first had presented pain and swelling over the upper arm, and was suspected as giant cell tumor in biopsy combined with hyperparathyroidism. Wide marginal excision and tumor prosthesis were performed. However, it was confirmed as brown tumor resulted from parathyroid adenoma according to laboratory findings and radioactive isotopes image, and surgical excision of adenoma relieved clinical symptoms. We report this case with a review of literatures.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.335-341
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• 2000

In this study, the multiobjective linear programming (MOLP) formulation was built to solve for the optimal forest management planning considering carbon sequestration and timber production simultaneously. The formulation was applied to a case study problem to investigate the trends of the optimal forest harvest schedules as the function of preference of forest management for carbon sequestration and timber production. The study site was Mt. Kari area in Hongchun. The formulation includes several site-specific constraints for non-declining yields, upper and lower bounds of cut volume and area for timber, ending inventory conditions, etc.. According to the changes of weight combinations for timber production and carbon sequestration, the joint production possibilities curve was proposed as the option for management choice.

• Structural Engineering and Mechanics
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• v.44 no.6
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• pp.775-799
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• 2012

This work approaches the structural performance of masonry arches that have a small ratio between number of vossoirs and span length. The aim of this research is to compare and validate three different methods of analysis (funicular limit analysis F.L.A., kinematic limit analysis K.L.A. and plane stress Finite Element Analysis F.E.A.) with an experimental campaign. 18 failure tests with arches of different shapes and boundary conditions have been performed. The basic failure mechanism was the formation of enough hinges in the geometry. Nevertheless, in few cases, sliding between vossoirs also played a relevant influence. Moreover, few arches didn't reach the collapse. The FLA and KLA didn't find a solution close to the experimental values for some of the tests. The low number of vossoirs and joints become a drawback for an agreement between kinematic mechanism, equilibrium of forces and geometry constraints. FLA finds a lower bound whereas KLA finds an upper bound of the ultimate load of the arch. FEA is the most reliable and robust method and it can reproduce most of the mechanism and ultimate loads. However, special care is required in the definition of boundary conditions for FEA analysis. Scientific justification of the more suitability of numerical methods in front of classic methods at calculating arches with a few vossoirs is the main original contribution of the paper.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.1
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• pp.73-80
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• 2000

The stewart platform manipulator proposed by stewart is the parallel manipulator which is composed of several independent actuators connecting the upper plate with the base plate and capable of executing a six degree of freedom motion. The manipulator has a structure of a closed loop form, and provides better load-to-weight ratio and ratio and rigidity than a serial manipulator with an open loop form. Moreover, the manipulator has high positional accuracy because position errors of actuators are not additive. Because of these advantages, this manipulator is widely used in many engineering applications such as a driving simulator, a tool of machining center, a force/torque sensor and so on. When this Stewart platform manipulator is controlled in joint space, it is difficult to design a controller using an analytic method due to nonhnearity and unknown parameters of actuators. Therefore, a PID controller is often used because of easiness in applications. To find the PID control gain, a trial-and-error method is generally used. This method is time-consuming, and does not guarantee a optimal gain. Thus, this paper proposes a GA-PID controller which selects an optimal PID control gain using genetic algorithms. And this proposed controller is evaluated experimentally and shows acceptable performance.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.6
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• pp.532-535
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• 2005

The objective of this study is assessment of the efficacy of upper joint space arthrocentesis on prevention of TMJ injury from patient with mantibular fractures. We divided the patients into two groups, one which consist of 24 patients who are taken arthrocentesis while open reduction of mandibular fracture, the other which consist of 27 patients without arthrocentesis from Jan 1999 to Dec 2001. We measured maximum mouth opening, excursive movement range respectively one week, one month, three months later after operation. The patients were instructed to mark on 10 cm VAS for evaluation of TMJ pain during resting, mouth opening, and mastication. We evaluated the signs and symptoms of temporomandibular disorder clinically and radiographically 6 months later. The result of this study is that there is a reduction of pain and increase of range of mandibular motion in both groups but in patients with arthrocentesis there is relatively reduction of pain and increase of range of mandibular motion compared with control group. On the points of 6 months later, temporomandibular disorder occurred in 4 patients (16.7%) in group with arthrocentesis and 13 patients (47.1%) in control group. In conclusion, we think that supplemental therapy such as arthrocentesis is helpful for the recovery of jaw function and prevention of the development of temporomandibular disorder after facial trauma.

• Journal of Korea Game Society
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• v.13 no.1
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• pp.19-30
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• 2013

This paper proposes a serious game for rehabilitation training targeting old persons and patients for rehabilitation. The serious game suggested for rehabilitation training provides the whole body movement recognition-based interface using the 3D depth camera. When the user stands before the camera, it distinguishes the user from the background and then recognizes the user's whole body with 15 joints. By analyzing the changes of location and direction of each joint, it recognizes gestures needed for the game. The game contents consist of the games for upper limb training, lower limb training, whole body training, and balance training, and it was realized in both 2D and 3D games. The system suggested in this article works robustly even with the environmental changes using the 3D depth camera. Even with no separate device, the game recognizes the gestures only using the whole body movement, and this enhances the effect of rehabilitation.

• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.429-436
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• 2010

The purpose of this study was to analyze the kinematic factors and throwing variables for the 3-turn and 4-turn techniques and for release as well as to provide technical advice for improving athletic performance in hammer throwing. Data analysis led to the following conclusions: To increase the rotation speed for the 3-turn and 4-turn techniques, the time elapsed during the 1-foot support period should be decreased the distance between the rotating foot and the rotation axis should be small and the height of the hip joint should be increased at the times of release The throwing angle at the moment of release should be more than 40 degrees, and the throwing position should be taken vertically high at the shoulder joints. To accelerate the motion of the hammer, the speed should not be reduced during the 1-foot support period but should be increased during the 2-foot support period for much greater acceleration. In the 3-turn technique, the angles of the shoulder axis and hummer string should be dragged angle at the maximum point and lead angle at the minimum point, and dragged angle at the maximum and minimum points in the 4-turn at the time of relase The upper body should be quickly bent backward, the knee angle should be extended, and the angles of the shoulder axis and hammer string should be dragged angle close to 90 degrees.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.1
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• pp.79-93
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• 1998

The eigenvalue problem is presented for the building with added viscoelastic dampers by using component mode method. The Lagrange multiplier formulation is used to derive the eigenvalue problem which is expressed with the natural frequencies of the building, the mode components at which the dampers are added, and the viscoelastic property of the damper. The derived eigenvalue problem has a nonstandard form for determining the eigenvalues. Therefore, the problem is examined by the graphical depiction to give new insight into the eigenvalues for the building with added viscoelastic dampers. Using the present approach the exact eigenvalues can be found and also upper and lower bounds of the eigenvalues can be obtained.

• Journal of the Korean Geophysical Society
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• v.4 no.1
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• pp.21-33
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• 2001

Simultaneous inversion of first-arrivals of local earthquakes recorded by the Korea Meteorological Administration(KMA) seismograph network from 1991 to 1998 is made to derive 1D crustal velocity structure of the Korean peninsula. Twenty-nine events with 178 observations are used in the inversion. Average crustal P-wave velocity turns out to be about 6.3 km/sec, and crustal thickness and upper mantle P-wave velocity are estimated as 33 km and 7.9 km/sec, respectively. Results of inversion indicate the possibility of the low velocity layer in the lower crust. Joint inversion is applied to estimate hypocenters, station delays, and velocities simultaneously. Relative station corrections for 11 stations range from zero to about 1.2 sec. Analysis of the synthetic data shows that estimates of hypocenter locations and station corrections as well as averaged crustal structure are reliable for the given data set..