• Archives of design research
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• v.19 no.6 s.68
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• pp.5-8
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• 2006

Inversion therapy has been used to relieve backpain, decrease pressure on the discs between vertebrae and stretch musdes as early as 400 BC. Gravity Guidance Inversion Table was introduced in 1960's and has been commercialized mostly for relieving backpain. in United States. But this machine needs to adjusted and possible sudden movement can cause severe injury to the users. In the 1990's, motor assisted inversion cram was introduced in Germany. But this inversion cram is too heavy and inconvenient to be used at home. In these days, the inversion machine become popular equipment in fitness clubs and health care places for relieving backpain as well as stretching muscles. And there is a growing need for home use version of motorized inversion machine. In this study, the motorized inversion machine was developed to be used for stretching exercise at home. The design became compact, simple and foldable as the results of adapting the wabble mechanism. And the machines are optimally designed by analyzing the torques applied to the machine by diverse physical size of users.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1330-1341
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• 1993

The kinematic synthesis deals with the systematic design of mechanisms for a given performance. The area of synthesis may be grouped into two categories to determine the type and to size the dimensions of a mechanism for a specified task. In this paper, using a database of mechanisms a designer can determine the type of mechanism conveniently and design equations are automatically generated for a given input performance. The solving method of design equations utilizes an optimization routine to obtain roots effectively. The linkages of 4, 6, and 8bars with revolute joints are considered in this study but may be extended to linkages of more bars.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.489-492
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• 2016

In this paper, 본 논문에서는 경사/장애물/특수표면을 이동할 수 있는 얀센 매커니즘 기반의 보행기구 설계에 대해 다루고 있다. 얀센 매커니즘 자체의 조건과 전체 보행기구의 조건을 알아보며, 기구의 완전한 회전운동 조건과 장애물이 있는 거친 표면을 이동할 수 있는 조건을 알아보고자 한다.

• Journal of Korea Game Society
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• v.10 no.6
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• pp.57-65
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• 2010

In this paper, mobility performance indices are proposed which may be used to estimate characteristics of output velocity space in six-degree-of-freedom parallel mechanism. In order for manipulability and condition number to not suffer from lack of the physical meaning due to dimensional inhomogeneity, output space is partitioned into translational velocity space and rotational velocity space, respectively. In each space, mobility ellipsoids corresponding to unit input space are defined and two types of mobility performance in translational velocity spaces indices are derived. Two types of mobility performance in rotational velocity spaces indices are derived.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.76-76
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• 2017

Ni-Ti 파일은 근관치료 시 근관형성에 사용되며 근관계 내 조직 잔사와 세균 을 포함한 모든 내용물을 제거하고 미세누출이 생기지 않도록 성공적으로 근관충전을 할 수 있는 근관의 형태를 만드는데 사용된다. Ni-Ti 파일은 수동형 파일처럼 날이 풀어지거나 예각으로 꺾이는 등 시각적으로 나타나는 파일의 피로도나 손상정도를 인지하기 어려워 파일이 근관 내에서 부러지는 것을 막기가 어렵다. Ni-Ti 파일은 육안으로 관찰 할 수 있는 구부러짐이나 풀림 등의 소성변형 없이 기구의 탄성한계 내에서 갑작스럽게 파절되는 경우가 있는데, 이는 만곡 근관 내에서 기구가 회전하는 동안 만곡의 안쪽에는 압축응력이, 만곡의 바깥쪽에는 인장응력이 반복적으로 가해짐으로써 파절의 표면에 미세 파절과 균열이 발생하고 전파되어 결국 피로파절(fatigue fracture)을 야기하게 된다. 또한 Ni-Ti파일이 반복응력을 받으면 균열이 형성되면서 파절이 야기되며 연성파절(ductile fracture) 양상을 나타낸다고 보고하였다. Ni-Ti 파일을 이용한 피로파절에 대한 이전의 연구에서는 파일의 직경이나 경사도 (taper), 단면 형태 및 회전속도, 표면결함 등이 파절에 영향을 미친다고 보고되고 있다. 사용하지 않은 Ni-Ti파일을 구부려 응력을 가 한 상태에서 주사전자현미경으로 관찰한 결과 기계 가공 과정에서 발생한 균열, 미세 결함, 긁힌 자국 및 불균질성 등이 원인으로 알려져 있다. 따라서 본 연구발표에서는 표면결함을 최소화하고 기구의 회전응력 하에서 피로파절저항성을 향상시키기 위한 방법에 대하여 알아보고자 한다.

• Journal of radiological science and technology
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• v.38 no.4
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• pp.389-394
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• 2015

There is a progressive development in the medical imaging technology, especially of descriptive capability for anatomical structure of human body thanks to advancement of information technology and medical devices. But however maintenance of correct posture is essential for the medical imaging checkup on the shoulder joint requiring rotation of the upper limb due to the complexity of human body. In the cases of MRI examination, long duration and fixed posture are critical, as failure to comply with them leads to minimal possibility of reproducibility only with the efforts of the examiner and will of the patient. Thus, this study aimed to develop an auxiliary device that enables rotation of the upper limb as well as fixing it at quantitative angles for medical imaging examination capable of providing diagnostic values. An auxiliary device has been developed based on the results of precedent studies, by designing a 3D model with the CATIA software, an engineering application, and producing it with the 3D printer. The printer is Objet350 Connex from Stratasys, and acrylonitrile- butadiene-styrene(ABS) is used as the material of the device. Dimensions are $120{\times}150{\times}190mm$, with the inner diameter of the handle being 125.9 mm. The auxiliary device has 4 components including the body (outside), handle (inside), fixture terminal and the connection part. The body and handle have the gap of 2.1 mm for smooth rotation, while the 360 degree of scales have been etched on the handle so that the angle required for observation may be recorded per patient for traceability and dual examination.

• Journal of the Korean Society of Radiology
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• v.18 no.2
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• pp.153-159
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• 2024

In X-ray projection, Unskilled radiologists become skilled through fail exam. This causes the patient to be exposed to unnecessary radiation. In this study, pre-position unskilled radiologic technologist presented ways to improve clinical proficiency. presented a skull lateral x-ray projection practice method using visual, spatial, and assistive devices. In addition, the accuracy and usefulness of the use of assistive devices were evaluated. When X-ray images were taken based on learning, the rotational spacing, which indicates image distortion, was 7.85 ± 1.45 mm and the tiliting spacing was 4.84 ± 0.5 mm. When practicing using visual aids, the rotational spacing is 4.4 ± 0.76 mm and the inclination spacing is 3.01 ± 0.87 mm. using a spatial compensation device, the rotational spacing is 5.2 ± 0.69 mm and the tiliting spacing is 3.33 ± 0.61 mm. Skull lateral X-ray Image distortion caused by empirical photography practice decreased by 5.4%, but image distortion caused by tilting increased by 1.2%. When practicing using a visual assistive devices, the degree of rotational spacing by 40.1% and the tiliting spacing decreased by 30.7% compared to the empirical x-ray exposure practice. When using spatial assistive devices, the rotation interval was reduced by 41.7% and the tilting interval by 23.7% compared to conventional empirical x-ray exposure practice. Therefore, if an unskilled radiologist practices using visual and spatial aids,the accuracy will be improved in skull lateral x-ray projection.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.591-596
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• 2022

Since 4-bar linkage widely used in various industrial fields has a fixed link length, it is inconvenient to add an independent link structure or control device to change the movement of output link. Therefore, this paper proposes a new concept of variable 4-bar linkage mechanism to selectively adjust the movement of the output link to fit desired situations, and applied to the commercial table fans, which is a representative product using a 4-bar linkage system. The optimal rotation angle steps for efficiency are determined experimentally and the appropriate lengths of linkage to fit each step are calculated analytically. Changes in the linkage length are implemented by the rotational motion using a grooved cylindrical cam and the feasibility of the proposed variable linkage mechanism is verified through fabrication and measurement. The presented variable link mechanism is expected to improve the efficiency of industrial robots and fuel valve systems.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.6
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• pp.543-551
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• 2015

In this study, a novel method for dimension measurement of large-scale moving objects using stereo camera with 2-degree of freedom (2-DOF) mechanism is presented. The proposed method utilizes both the advantages of stereo vision technique and the enlarged visibility range of camera due to 2-DOF rotary mechanism in measuring large-scale moving objects. The measurement system employs a stereo camera combined with a 2-DOF rotary mechanism that allows capturing separate corners of the measured object. The measuring algorithm consists of two main stages. First, three-dimensional (3-D) positions of the corners of the measured object are determined based on stereo vision algorithms. Then, using the rotary angles of the 2-DOF mechanism the dimensions of the measured object are calculated via coordinate transformation. The proposed system can measure the dimensions of moving objects with relatively slow and steady speed. We showed that the proposed system guarantees high measuring accuracy with some experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.485-486
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• 2006

This paper represents a ultra precision rotational device where the smooth impact drive mechanism(SIDM) is utilized as a driving mechanism. Linear motions of piezoelectric elements are converted to the rotational motion of disk by frictional forces generated between the rotational disk and the friction bars which are attached to the piezoelectric elements. This device was designed to drive a rotational disk using slip-slip motion mechanism based on stick-slip motion mechanism. Experimental results show that the angular velocity was increased in proportion to the magnitude of supplied voltage to piezoelectric element. In our device, the smooth rotational motion was obtained when the driving frequency has been reached to 500Hz under the driving voltage of 100V. The amount of step movement has been revealed to be $3.44{\times}10^{-4}$ radian.