• Tribology and Lubricants
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• 제20권6호
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• pp.322-329
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• 2004

Recently, a load/unload(L/UL) system is adopted to the hard disk drive(HDD) due to its advantages such as lower power consumption, larger data zone, simpler fabrication of disk due to no bumped parking zone, and rarer contact between slider and media. An analysis of the transient motion for the slider is very important to design an air bearing surface(ABS) of the slider to secure the stable performance of the system. During the L/UL process, however, there are several issues occurred such as contact or collision between slider and media. Sometimes this will cause the system failure. In this study, the dynamics of a pico slider during the loading process are investigated through numerical simulation using FEM analysis and experiment. Ramp profile and angular velocity of the swing arm actuator are very important parameters for the design of L/UL system to avoid collision between slider and disk.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.406-411
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• 2003

One of the trends on information storage device is focused on the development of micro-optical devices with OFH (Optical Flying Head). Many different types of sliders for OFH and optical component systems have been introduced in the literature. However, the important issue on the mechanical system, which consists of suspension, swing arm and VCM (Voice Coil Motor) part has not been discussed up to date. In this research, we analyses the suspension, which is used for the small form factor MO drive. The analysis is in process two ways. One is probabilistic analysis, another is dynamic shock analysis. Probabilistic analysis is a technique you can use to assess the effect of uncertain input parameters and assumptions on your analysis model. Using a probabilistic analysis you can and out how much the results of a finite elements analysis are affected by uncertainties in the model. Dynamic shock analysis is used for the mobile applications. The mechanical robustness of the suspension simulating the shock responses of a disk-suspension is proposed in this paper.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.780-785
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• 2003

Recently the trends in information storage devices need small size, mobility, high capacity, and low power consumption etc. To satisfy those, the development of high performance actuator is an important issue. Compared with general linear actuator for optical disk drive, swingarm type rotary actuator is suitable to design in small form factor and has fast access time for random access. Swingarm actuator is designed considering the structural problem and the actuating force of VCM(Voice Coil Motor). The increase of mass caused by optical components makes vibration problems of swing-arm, therefore resonance frequency should be increased and inertia has to be reduced. ANSYS FEM tool is employed in optimizing swingarm. The VCM is designed using 3-D electro-magnetic analysis, and parameters of magnetic circuit are determined to matte large flux density. The large flux density enables to achieve low power consumption. VCM holder is designed to get the mass balance of total actuator and this balance reduces the magnitude of critical mode relative to pivot bearing, It is expected that swingarm type rotary actuator designed by this method is available to variable type of micro optical disk drives.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.511-512
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• 2007

The monitoring system has won acceptance as a premium mark that identifies the highest standard of product quality in advanced industry. The TOP features with multi-I/O ports and VGA & RCA TV-out ports supporting mirroring & multiple dual-display modes by windows 0/5. With the choice of versatile stands, panel mount, or VESA wall-mount swing arm and connecting to modem. Wireless keyboard, Customer Display and Card Reader, is your idea Panel system for the application of TOP(Touch Operation Pannel), KIOSK, or Office / Factory Automation. TOP is the hardware and software product that transacts all kind of functions for advanced technology equipment to button, switch, voice and graph etc so that let consumer use easily Industrial HMI System Touch Panel. System characteristics: Easy of use and flexibility to the user, Present a high value solution and advanced function for many Application, Factory Automation, Office Automation, Building Automation System, Information Service System, etc. Analog Touch - 2MB Flash Memory for Saving Screen Data - RS-232C/422 Serial Port - Multi Language Support.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.227-231
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• 2004

Technological advance in information technology has sparked the necessity of small form factor (SFF) optical disk for mobile devices. Small form factor optical disk is highly anticipated to be a next generation storage device because it can be used for a cost-effective way compared with solid state memory. For the application to the 5 mm height small-form-factor optical disk drive, we have presented an optical flying head and swing arm actuator. In this study, we propose a small 1-axis actuator for compensating ficus error and SA due to the variation of cover-layer thickness in the cover-layered small optical disk. The main design issues of the 1-axis actuator are the realization of compact structure and the new support structure of the actuator: Finally, the compensating principle and performance of the 1-axis actuator will be explained.

• 드라이브 ㆍ 컨트롤
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• 제19권2호
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• pp.11-16
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• 2022

It is important to measure the excavator's work productivity that estimates the bucket's payloads on a process. If the bucket isn't filled at every working cycle, the excavator's operator has to drive the machine more to achieve his work quota. If bucket is filled over with the load, the other way around, the transferred object has to spread out on the workplace. That causes additional work to clean the site. This paper proposes a method that can estimate the bucket's payload to improve the excavator's work productivity. This method assumes that the excavator is a lumped mass system. And it uses a 3 points angle (boom link, arm link, swing) and 2 points pressure (boom cylinder's input port and output port) of measurable data. Depending on assumptions, the bucket's payload can be calculated by the payload's motion equation. And this suggested method can be verified by simple experiments.

• 한국운동역학회지
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• 제12권2호
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• pp.91-107
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• 2002

이 연구는 배드민턴 경기기술 중 클리어에 대한 연구 대부분 경기분석 및 타법사용에 대한 연구에 국한되어 있어 여자중학생 배드민턴 선수를 대상으로 하이클리어 동작을 운동학적 변인으로 측정 분석하였다. 이 연구의 대상자는 충청북도에 위치한 C여자중학교 배드민턴 선수 4명이었으며, 동작의 분석 범위는 준비자세에서 동작의 시작순간, 라켓이 최대로 백 스윙 된 순간, 라켓과 셔틀콕이 임팩트 되는 순간, 임팩트 이후의 마무리 스윙동작까지로 단계별 동작을 설정하였다. 여자중학생 하이클리어 동작을 운동학적으로 분석한 결과 다음과 같은 결론을 얻었다. 피험자 대부분 백 스윙 단계에서 어깨 및 팔꿈치 관절을 충분히 회전하지 못한 것으로 나타났고, 특정 관절 부분에만 좋은 동작을 나타내 관절의 협용동작이 떨어지는 것으로 보였다. 피험자 S1과 S2가 임팩트 단계에서 어깨 및 팔꿈치 관절은 크게 천천히 스윙하다가 오른 손목관절 및 라켓헤드의 속도는 빠르게 나타나 다른 피험자 보다 관절의 협웅동작이 잘 이루어진 것으로 나타났다. 피험자 모두 성장기에 있는 학생으로서 관절의 유연성에 기인하여 오른 어깨각도 변화는 큰 각도를 보였고 각속도는 피험자 S3이 다른 피험자 보다 기술적 차이를 보여 개선될 점으로 나타났다. 피험자 모두 오른 팔꿈치 각도 변화는 비슷한 양상을 보였고 각속도에서 피험자 S2는 백 스윙단계부터 임팩트 시 심한 굴곡의 형태를 보여 힘을 효과적으로 사용하지 못한 것으로 나타났다. 피험자 모두 오른 손목각도의 변화는 백 스윙 직후 큰 각도를 이루지 못하고 임팩트 직후 손목의 빠른 굴곡이 형성되지 못하여 셔틀콕의 속도가 감속될 것으로 나타났다. 그러나 각속도는 피험자 S1과 S4는 임팩트 시 음(-)의 각속도 값을 보여 강한 스냅을 이용하고 빠르게 움직이고 있다고 볼 수 있다. 피험자 모두 임팩트 시 무릎각도의 크기는 큰 각도를 이룬 반면 고관절 각도는 작은 각도를 보여 무릎관절과 고관절과의 합성동작인 강한 허리힘을 이용하지 못한 것으로 나타났다.

• 한국운동역학회지
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• 제16권3호
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• pp.65-74
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• 2006

This study was attempted to Kinematical characteristics of the Endo $360^{\circ}$El-grip Swing on the horizontal bar. To do this, we selected and analyzed the performance of two athletes who did Endo $360^{\circ}$El-grip Swing in the horizontal bar competition of male artistic gymnastic in the 22nd Universiad Games 2003 Daegu. We drew the conclusions from the kinematical factors that were came out through analyzing three-dimensional cinematography of the athletes' movements, by using two video cameras. In point of analyzing the actual competition situation, it is expected that gymnastics and coaches have the effective informations, and the following conclusion had resulted. 1. When performing Endo $360^{\circ}$El-Grip, the average for entire required time was $1.93{\pm}0.06sec$. The average for descent phase time was $0.24{\pm}0.02sec$, ascent phase time was 0.22${\pm}0.07sec$, connecting phase time was $0.87{\pm}0.07sec$, and El-Grip phase time was $0.61{\pm}0.02sec$. The descent phase need short period of time but however to have a stable performance, ensuring ascent and connecting phase time are needed. El-Grip phase need short period of time to have a stable re-grasp. 2. To have a convenient preparation for El-Grip in descent and ascent phase, lowering CM, and ease up in sway and plunge from the High Bar would make descent and ascent even more faster and would have increase effect in trunk rotation. 3. In descent and ascent phase, if shoulder angle and arm slope is dwindling then it would effect rotation angle so might risk it from hitting a Bar when putting legs in and out. 4. In connecting phase, it requires some time to show stable performance when El-Grip phase is continued by using hip angle which would make trunk rotation angle bigger and make descent and ascent time slower. 5. In El-Grip phase, when doing motions like hand standing. using hip angle more than maximum would make CM even faster and it is stable position while performing.

• The Journal of Korean Physical Therapy
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• 제25권5호
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• pp.239-245
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• 2013

Purpose: Osteoarthritis occurs in many different joints of the body, causing pain, stiffness, and decreased function. The knee is the most frequently affected joint of the lower limb. The aim of this study was to investigate the differences of biomechanics between independent gait and anterior walker dependent gait of patients with osteoarthritis of the knee. Methods: Lower limb joint kinematics and kinetics were evaluated in 15 patients with knee osteoarthritis when walking independently and when walking with an anterior walker. Participants were evaluated in a gait laboratory, with self-selected gait speed and natural arm swing. Results: When walking with a dependent anterior walker, participants walked significantly faster (p<0.01), using a longer stride length (p<0.01), compared to independent gait. When walking with a dependent anterior walker, participants exhibited significantly greater knee flexion/extension motion (p<0.01) and lower knee flexion moment (p<0.05) compared to independent gait. When walking with a dependent anterior walker, participants showed significantly greater peak ankle motion (p<0.01), ankle dorsiflexion/plantarflexion moments (p<0.01), and ankle power generation (p<0.05) compared to independent gait. Conclusion: These biomechanical properties of gait, observed when participants walked with a dependent anterior walker, may be a compensatory response to impaired knee function to allow sufficient power generation for propulsion. Therefore, rehabilitative strategies for patients with osteoarthritis of the knee are needed in order to improve not only knee function but also hip and ankle function.

• 한국운동역학회지
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• 제16권4호
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• pp.125-134
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• 2006

The purpose of this study was to analyze the Biomechanical elements by looking at the differences on the motions of the right and left spikes of right-handed offense volleyball players, using 3D image analysis and force platform. For that purpose, spike motions of six male university volleyball players were recorded three times each using two 16mm high speed cameras and the speed of recording was set at 60 frames/sec. The coordinated raw data was leveled as 6Hz using low pass filtering method and the calculation of 3D coordinates was done by using a DLT (Direct Linear Transformation) method. Also KWON 3D program was used to analyze the variables. Through the experiments and research, the following results were found: That is, in case of the right spike, the required time from the toss to the impact, which affected the success rate of offense showed as longer and on the take-off, the exact timing to touch the ball was longer because the pace between right and left feet was wider, and also after the jump, the distance between the feet indicated shorter, than the left. In addition, the degree of somersault and horizontal adduction of shoulder joint was smaller and the degree of medial rotation of shoulder joint showed bigger than the left, so it indicated that it was not centered on the body, but by the arm with an axis of shoulder using a swing motion. After the impact, the speed of the ball indicated slower compared to the left spike.