• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.12 no.4
• /
• pp.75-80
• /
• 1998

In this paper, the real time characteristics analyzing system is proposed to analyze characteristics of inverter. The system is consisted of DSP unit and personal computer. Conventionally, power conversion system is designed by the load and the use. And control characteristics for the designed power conversion system is evaluated by the control input. In order to study of control methods, power conversion system is required for a study of control methods and observed system is required for a analyzing of the inverter. Inverter system is consisted to evaluate for proposed real time characteristics analyzing system. And induction motor is driven by control input that is manufactured by personal computer. Output of inverter and control characteristics is variously analyzed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2006.05a
• /
• pp.135-138
• /
• 2006

각종 현장 및 시설물에는 모터를 이용하여 작업하는 전기실 또는 기계실 등이 많이 있다. 이러한 경우, 모터를 제어하는 배전반의 일종인 모터제어센터(MCC)와 중앙통제실에는 데스크 판넬(desk panel)이 설치되며, 현장마다에는 각각의 로컬 판넬(local panel)이 설치되어 있다. 현재 이러한 구성요소들은 많은 유선으로 연결되어 있으며, 각각의 유니트(unit) 마다 나오는 접점신호의 온(on)/오프(off) 신호가 중앙통제실의 데스크 판넬에 전달되고 있다. 본 논문에서는 무선 LAN 환경에서 모터의 감시 및 제어를 위한 시스템에 관한 연구이다. 즉, 현장에서 근무자의 직접적인 모터의 동작 상태 확인 및 작동을 위한 불편함을 해소하기 위하여, 무선 LAN 환경을 통하여 모터제어센터의 감시 제어를 위한 시스템의 구현이다. 이를 위하여, 모터제어센터와 모터 감시 시스템(컴퓨터) 간의 데이터 전송을 위해서 무선 LAN의 블루투스 통신모듈을 이용한 RF 송 수신기 및 관리자를 위한 감시(모니터링) 프로그램을 구현하였다.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.7
• /
• pp.770-777
• /
• 2012

This paper deals with the design and modal characteristics analysis of a drive-train for a paralleltype hybrid electric vehicle (HEV). The function of the drive-train system (DTS) in the HEV combines or divides the torque and velocity from the internal combustion engine along with the induction motor. The system consists of a compound planetary gear and unit's electromagnetic clutch to provide the operation modes such as Engine Only (EO), Electric Vehicle (EV), and Hybrid Electric Vehicle (HEV) modes. In order to investigate the characteristics of the velocity and torque flow for the system, dynamic models of the HEV with DTS are derived from the prototype DTS. The performance of the derived dynamic models is evaluated by both computer simulations and experiments according to each mode.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.5
• /
• pp.968-975
• /
• 1988

The maximum feedrate generated from the hardware DDA is closely related to its calculation efficiency. The smaller interpolation span results in the lower calculation efficiency. This paper presents the method to improve the calculation efficiency for the smaller interpolation span. For the linear interpolation the higher calculation efficiency can be achieved by putting biggest value that the interpolation DDA can hold. for the circular interpolation, however, the scheme used for linear interpolation does not work since arbitrary change of value in the interpolation DDA changes the radius of the circle. The bit length of the hardware DDA is adjusted instead of adjusting the value in DDA, which results in the every same effect on calculation efficiency for the circular interpolation. The hardware circuit and supporting software are designed, and tested by two axis step motor driven milling machine. The experimental results show that the proposed method drastically increases the maximum feedrate even for the smaller interpolation span.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.65-69
• /
• 2004

The small form factor optical data storage devices are developing rapidly nowadays. Since it is designed for portable and compatibility with flash memory, its components such as disk, head, focusing actuator, and spindle motor should be assembled within 5 m thickness. The thickness of focusing actuator is within 2 mm and the total working range is $+/-100{\mu}m$, with the resolution of less than $1{\mu}m$. Since the thickness is limited tightly, it is hard to place the yoke that closes the magnetic circuit and hard to make strong flux density without yoke. Therefore, Halbach array is adopted to increase the magnetic flux of one side without yoke. The proposed Halbach array type focusing actuator has the advantage of thin actuation structure with sacrificing less flux density than conventional magnetic array. The optical head unit is moved on the swing arm type tracking actuator. Focusing coil is attached to swing arm, and Halbach magnet array is positioned at the bottom of deck along the tracking line, and focusing actuator exerts force by the Fleming's left hand rule. The working range and resolution of focusing actuator are analyzed with FEM and experiment.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.8
• /
• pp.3647-3653
• /
• 2012

In active noise control filter, IIR filter structure which used for control filter assures the stability property. The stability characteristics of IIR filter structure is mainly determined by pole location of control filter within unit disc, so stable selection of the value of control filter coefficient is very important. In this paper, we proposed novel adaptive stabilized Filtered_U LMS algorithms with IIR filter structure which has better convergence speed and less computational burden than conventional FIR structures, for multi-channel active noise control with vehicle enclosure signal case. For better convergence speed in adaptive algorithms, fuzzy LMS algorithms where convergence coefficient computed by a fuzzy PI type controller was proposed.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.23 no.60
• /
• pp.37-46
• /
• 2000

A biomechanical model of lower extremity in seated postures was developed to assess muscular activities of lower extremity involved in a variety of foot pedal operations. The model incorporated four rigid body segments with the twenty-four muscles to represent lower extremity This study deals with quasi-static movement to investigate dynamic movement effect in seated foot operation. It is found that optimization method which has been used for modeling the articulated body segments does not predict the forces generated from biarticular muscles and antagonistic muscles reasonably. So, the revised nonlinear optimization scheme was employed to consider the synergistic effects of biarticular muscles and the antagonistic muscle effects from the stabilization of the joint. For the model validation, three male subjects performed the experiments in which EMG activities of the nine lower extremity muscles were measured. Predicted muscle forces were compared with the corresponding EMG amplitudes and it showed no statistical difference. For the selection of optimal seated posture, a physiological meaningful criterion was developed for muscular load sharing developed. For exertion levels, the transition point of type F motor unit of each muscle is inferred by analyzing the electromyogram at the seated postures. Also, for predetermined seated foot operations exertion levels, the recruitment pattern is identified in the continuous exertion, by analyzing the electromyogram changes due to the accumulated muscle fatigue.

• Physical Therapy Korea
• /
• v.28 no.4
• /
• pp.245-250
• /
• 2021

Background: The International Classification of Functioning, Disability, and Health-Child and Youth version (ICF-CY) is designed to record the characteristics of developing children and examine the influence of a child's environment on their health. Objects: This study was designed to determine the relationship between the clinically extracted ICF-CY items and The Pediatric Evaluation of Disability Inventory (PEDI) and Gross Motor Function Measure (GMFM) items. Methods: Thirty patients (17 males and 13 females) who were hospitalized in a pediatric and youth patient unit of a rehabilitation hospital were included in the study. Four health professionals (two physical therapists and two occupational therapists) working independently linked the PEDI and GMFM-66 items to the activity and participation domains of the ICF-CY. Results: There were strong negative correlations between the ICF-CY subdomains and the PEDI subdomains (r = 0.76-0.95; p < 0.05). There were positive strong correlations between the ICF-CY subdomains and the GMFM-66 (r = 0.76-0.95; p < 0.05). Conclusion: The extracted ICF codes were a valid tool for evaluating the mobility and selfcare conditions of cerebral palsy in the pediatric rehabilitation area.

• Journal of IKEEE
• /
• v.23 no.1
• /
• pp.261-265
• /
• 2019

We analyze the failure rate change of a conventional bidirectional converter and a modified one which moves an output capacitor towards propulsion battery. We analysis of the circuit structural homogeneity and the difference between both converters, and confirm that the capacitor working voltage is reduced by changing the capacitor position. After obtaining the capacitor failure rate according to voltage stress factor and operating temperature, it is applied to the fault-tree of the bidirectional converter to obtain the overall failure rate of the converter. We analyzes the advantages and disadvantages of design changes by comparing and analyzing the failure rate and mean time between failures (MTBF) according to operating temperature and capacitance value.

• Journal of Electrodiagnosis and Neuromuscular Diseases
• /
• v.20 no.2
• /
• pp.112-118
• /
• 2018

We describe a case of a 71-year-old male patient who experienced progressive bilateral proximal upper limb weakness and atrophy without sensory symptoms and signs over 5 years. Electromyography demonstrated denervation potentials and neuropathic motor unit action potentials on C5-C7 myotome muscles bilaterally. Cervical spine magnetic resonance imaging revealed engorged anterior epidural venous plexus, T2 hyperintensity localized to grey matter ("snake-eye" appearance) at C2-C6 vertebral level, and ventral epidural fluid collection from C6 to T8 vertebral level. This case indicates that bibrachial amyotrophy associated with epidural fluid leak should be suspected in patients presenting with progressive bilateral upper limb weakness and atrophy without sensory involvement.