• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.165-173
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• 2020

ABS and PLA are applied for restoring missing part of damaged ceramics, but are not similar to the material of ceramics, so this study conducted a research on the properties and applicability of ceramic resin. This study conducted actual restoration of ABS and ceramic resin as well as cast restoration method with experiment of properties. Results show that manufacturing of restored part showed higher precision than existing materials, which enables printing of tiny shapes showing excellent surface texture and gloss than L30 and ABS resin. As a result of measuring properties, the material showed excellent durability than existing materials with no contraction and deformation and compressive strength, but value of specific gravity and hardness can lower processability after manufacturing. Long-term monitoring, evaluation of reliability of ceramic resin applied in this study, additional researches on the restorability of the original shape when printing too thin or long restored part are needed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.3
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• pp.296-303
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• 2014

In this paper, we propose an algorithm to visualize radio wave environment based on the measured Received Signal Strength Indication( RSSI) and 3D geographic information. We estimate the source position using the circumcenter of the triangle and visualize the radio wave environment using the empirical propagation models. A mode seeking algorithm(mean-shift clustering) is used to seek the peak points and the center of gravity is utilized to reduce the estimation errors. Our approach finds its applications in the radio wave monitoring systems for the efficient utilization of radio resources.

• Journal of Acupuncture Research
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• v.31 no.4
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• pp.185-193
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• 2014

Objectives : The purpose of this study is to find the effectiveness of Korean medical treatment on sense of balance by cerebral hemorrhage. Gaitview analysis and Berg balance scale(BBS) research were used to evaluate it. Methods : We selected patients who were hospitalized at the Kangnam Korean Hospital, Kyung Hee University Hospital from May 2014 to August 2014 that satisfied inclusion/exclusion criteria. Before taking treatment, we took gaitview analysis and BBS first to analyze the ability of balance and gait of patients. In gaitview analysis, we checked Center of gravity(COG), pressure ratio, ave pressure, gait time ratio, statistic score. For about 10 days, patients were given acupuncture treatment, herbal medicine and physical therapy. Afterwards, we compared patients' progression between before-treatment and after-treatment with the same evaluation scale. Results : In the period of treatment, patients showed static and dynamic index change within the normal range or increase. And in statistic score, 2 cases score are increased. In BBS, all cases score are increased. Conclusions : Korean medical treatment improves imbalance symptom of cerebral hemorrhage patient. So the ability of gait and activity of daily living is improved. But, this study has only 3 cases, and has no comparable study. Prospective and Larger study will be necessary.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.571-575
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• 2015

This paper propose a temporal histogram -based behavior pattern analysis algorithm to analyze the movement features of moving objects from the image inputted in real-time. For the purpose of tracking and analysis of moving objects, it needs to be performed background learning which separated moving objects from the background. Moving object is extracted as a background learning after identifying the object by using the center of gravity and the coordinate correlation is performed by the object tracking. The start frame of each of the tracked object, the end frame, the coordinates information and size information are stored and managed by the linked list. Temporal histogram defines movement features pattern using x, y coordinates based on time axis, it compares each coordinates of objects for understanding its movement features and behavior pattern. Behavior pattern analysis system based on temporal histogram confirmed high tracking rate over 95% with sustaining high processing speed 45~50fps through the demo experiment.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.4
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• pp.443-448
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• 2006

In this paper, a novel method is proposed for generating the low-power and stable walking trajectory of biped robots, and then a biped robot with 25 DOFs(degrees of freedom) is designed and implemented for the realization of the low-power walking trajectory generated by the proposed method. In our method, first a stable VPCG(vertically projected center of gravity) trajectory is generated, and then the trajectories of ankle and pelvis of a biped robot are planned to follow the preplanned stable VPCG trajectory, which produces a waking pattern without bending its knees and enables a biped robot to walk with less power consumption. On the other hand, a biped robot implemented in this paper has the mechanical structure of foot that enables a biped robot to support on the ground well, and the mechanical structure of pelvis that enables a biped robot to move flexibly. From results of the walking experiment and power consumption measurement, it was confirmed that the proposed method can generate the more stable and flexible trajectory with less power consumption compared with the existing methods which do not use the ankle of a biped robot.

• Physical Therapy Korea
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• v.10 no.4
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• pp.85-94
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• 2003

본 연구에서는 근골격계 통증이 자세유지와 균형능력에 핵심이 되는 중력중심 이동에 미치는 영향에 대해 알아봄으로서, 균형과 자세에 영향을 주는 다양한 요소들에 대한 새로운 접근을 시도해 보고자 한다. I-병원의 입원 및 외래 환자 중 신경계 손상이 없고 중력중심 이동에 직접적인 영향을 줄 수 있는 하지에 정형외과적 장애가 없으며, 전정계 손상이나 시력장애로 인한 균형에 문제가 없이 근골격계 질환으로 요통과 견통을 주소로 하는 71명의 환자(남자 38, 여자 33; 평균연령=44, 표준편차=13.8, 범위=19~79)와 신경계, 근골격계 및 평형감각에 문제가 없는 정상인 30명의 대조군(남자 16, 여자 14; 평균연령=39.2, 표준편차=13.7, 범위=21~72)을 대상으로 전산화된 힘판을 이용하여 중력중심 이동의 궤적을 표준편차값으로 측정하였다. 측정된 중력중심 이동값은 두 군간에 상이한 차이를 보이고 있음이 검증되었다(p<.01). 또 측정된 여러 변수들의 중력중심 이동에 대한 영향력을 알아보기 위해 나이, 체중 및 신장과 중력중심 이동과의 상관분석 결과 중력중심 이동의 15.8%를 체중의 변화에 의한 것으로 설명할 수 있다는 결과를 얻었으며, 그 외의 변수들과의 연관성에 대해선 유의미한 차이가 없었다(p<.01). 결과적으로 근골격계 통증은 올바른 자세유지와 균형유지를 위한 감각통합과 반응과정에 직접, 간접적으로 영향을 미치고 있다. 따라서 중력 중심 이동이 크면 클수록 중심을 잡기 위한 근육활동으로 추가적인 에너지가 사용되고, 편중된 중력중심 이동은 근골격계에 무리한 부담을 주어 통증을 증가시킬 수 있을 것이다. 또 통증으로 인한 중력중심 이동은 이를 보상하기 위해 신체 먼 곳에서의 이차적인 변형을 초래하여 각종 근골격계 증상의 원인이 될 수 있으므로 근골격계에 대한 적절한 치료는 통증을 감소시켜 자세의 이차적인 변형을 막고 자세유지 시 작용하는 근육의 에너지 효율을 높일 수 있을 것으로 사료된다.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.235-243
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• 2020

Lumbar Lordosis Angle (LLA) is an index that can be used to evaluate the curvature of the lumbar vertebrae. It can measure the structural stability of the lumbar spine and the stability of each segment of the vertebral column at the intervertebral disc angle (IDA). Especially, our data shows it is found to be a strong positive correlation between obesity and the angle of lordosis for lumbar vertebrae. Also, the reason for the large IDA in the case of obesity seems to be the result of the weakening of anatomical structure as well as the gravity effect. And, the obesity interferes with normal sagittal balance and fails to maintain a straight posture with minimal energy. Therefore, the obesity can be an important factor in causing back pain by changing the lumbar lordosis.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.5
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• pp.563-569
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• 2015

A chemical reaction occurring in CSTR (Continuous Stirred Tank Reactor) is significantly affected by the concentration, temperature, pressure, and reacting time of materials, and thus it has strong nonlinear and time-varying characteristics. Also, when an existing linear PID controller with fixed gain is used, the performance could deteriorate or could be unstable if the system parameters change due to the change in the operating point of CSTR. In this study, a technique for the design of a fuzzy PD plus I controller was proposed for the temperature control of a CSTR process. In the fuzzy PD plus I controller, a linear integral controller was added to a fuzzy PD controller in parallel, and the steady-state performance could be improved based on this. For the fuzzy membership function, a Gaussian type was used; for the fuzzy inference, the Max-Min method of Mamdani was used; and for the defuzzification, the center of gravity method was used. In addition, the saturation state of the actuator was also considered during controller design. The validity of the proposed method was examined by comparing the set-point tracking performance and the robustness to the parameter change with those of an adaptive controller and a nonlinear proportional-integral-differential controller.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.5
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• pp.2156-2170
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• 2020

This paper presents a fire detection algorithm with a minimal false detection rate, intended for a thermal imaging surveillance environment, whose properties vary depending on temporal conditions of day or night and environmental changes. This algorithm was designed to minimize the false detection alarm rate while ensuring a high detection rate, as required in fire detection applications. It was necessary to reduce false fire detections due to non-flame elements occurring when existing fixed threshold-based fire detection methods were applied. To this end, adaptive flame thresholds that varied depending on the characteristics of input images, as well as the center of gravity of the heat-source and hot-source regions, were analyzed in an attempt to minimize such non-flame elements in the phase of selecting flame candidate blocks. Also, to remove any false detection elements caused by camera shaking, one of the most frequently raised issues at outdoor sites, preliminary decision thresholds were adaptively set to the motion pixel ratio of input images to maximize the accuracy of the preliminary decision. Finally, in addition to the preliminary decision results, the texture correlation and intensity of the flame candidate blocks were averaged for a specific period of time and tested for their conformity with the fire decision conditions before making the final decision. To verify the fire detection performance of the proposed algorithm, a total of ten test videos were subjected to computer simulation. As a result, the fire detection accuracy of the proposed algorithm was determined to be 94.24%, with minimum false detection, demonstrating its improved performance and practicality compared to previous fixed threshold-based algorithms.

• Journal of IKEEE
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• v.6 no.1 s.10
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• pp.30-39
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• 2002

In this paper, we proposed a new circuit construction method that reduces the number of circuit devices of fuzzy controller. Sasaki had defined a new operator to eliminate the divide circuit comparing with the center of gravity method which often using to design the fuzzy controller. In this paper we obtained the more compacted fuzzy controller's circuit by using the proposed definition of fuzzification and defuzzification than using the Sasaki's method and the fuzzification and defuzzification are reverse operation each other. Using these definitions we exhibit the new design method and circuit structure that can eliminate the bounded product(BP) circuit included in Sasaki's circuit. Using the proposed method to level controlling of the water tank, we verified the fuzzy controller's performance by using existent method and proposed method. As a result that are calculated by using the Proposed fuzzy controller to level controlling of the water tank, total numbers of blocks and devices were decreased. If the number of variables and antecedents are Be11ing larger, this method is more efficient.