• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.3
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• pp.237-242
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• 2016

The major advantage of slip-ring technology in Spiral CT is that it facilitates continuous rotation of the x-ray tube, so that volume data can be acquired from a patient quickly. Not only for such a fast scan, but also for the dose reduction purpose, high signal-to-noise ratio and fast data acquisition system is required. In this study, we have built a multi-channel photodetector and multi-channel data acquisition system for CT application. The detector module consisted of CdWO4 crystal and Si photodiode in 16 channels. For the performance test of the preamplifier stage, both the transimpedance and switched integrator types are optimized for the photodetector modules. Switched integrator showed better noise performance in the limited bandwidth which is suitable for the current CT application. The control sequence for data acquisition and 20 bit ADC is designed with VHDL(Very High Speed Integrated Circuit Hardware Description Language) and implemented on FPGA(Field Programmable Gate Array) chip. Our Si photodiode detector module coupled to CdWO4 crystal showed comparable signal with other commercially available photodiode for CT. Switched integrator type showed higher SNR but narrower bandwidth compared to transimpedance preamplifier. Digital hardware is designed by FPGA, so that the control signal could be redesigned without hardware alteration.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.957-962
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• 2005

Today, the elderly is increasing gradually in the Republic of Korea society and this problem will be more serious in the near future. Therefore, engineering support for aged people is required. We are establishing a new field of healthcare engineering for elderly people and aiming to support for aged people and disabled people using adaptive control and instrument technology. In this paper, the goal is to implement the shared control of a robot mobility aid for the elderly. As using this type of assistive technology to be useful by its intended user community, it supports elderly people and handicapped people to live independently in their private homes. The interface transforms the force applied by the user into the robot's motion. Devices like buttons, joysticks, and levers already exist for relaying user input; however, they require hand displacement that would loosen or otherwise release the user's hold. Such interfaces make operation very difficult and potentially unsafe. Therefore, we propose a shared control system. It's safe more than joysticks and buttons. The shared control is a means of registering the user's intention through physical interaction. It's an important component in the development of robotic elderly assistant. The concept of shared control describes a system which is two or more independent control systems. We are using that the three component blocks consist of pressure sensor (flexible force sensor), circuit of measurement and transfer function. Experimental trials of this paper have been tested at the indoor environment. The robot is able to know the user intended direction through haptic device were logged along with the robot's force sensor.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.7 no.2
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• pp.55-62
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• 2013

The exoskeleton robot to assist walking of hemiplegia patients or disabled persons has been studied in this paper. The exoskeleton robot with degrees of freedom of 2 axis has been developed and tested for joint motion. The obtained EMG signal from normal person was analyzed and the control signal was extracted from it for convenient and automotive performance of assistance robot to help hemiplegia patient walks as normal person does. the purpose of using FES(Functional Electrical Stimulation) for hemiplegia patient's walk is to restore damaged body function by this, but this could give fatal electrical shock to patients by wrong use or cause quick fatigue in muscle by continuous stimulation. The convenient movement of hemiplegia patients with minimum muscle fatigue was looked possibly by operation of assistance robot exoskeleton using control signal. and the walking assistance exoskeleton robot seemed works more efficiently than using FES stimulator. The experiment in this study was performed based on usual motion in our life like walking, standing-up, sitting-down, and particularly feedback control system using Piezo sensor along with button switch was applied for smooth swing motion in walking. The experiment also shows that hemiplegia patients can move conveniently by using electromyogram signal of healthy leg for the operation signal of assistance robot system attached at damaged symmetrical leg.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.4
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• pp.305-313
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• 2016

Movements of the lower limb are important for normal walking and smooth oscillation of the center of gravity. The ankle rotations such as dorsi-flexion, plantar-flexion, inversion and eversion allows the foot to accommodate to ground during level ground walking. Current below knee (B/K) prostheses are used for replacing amputated ankle, and make it possible for amputees to walk again. However, most of amputees with B/K prostheses often experience a loss of terrain adaptability as well as stability because of limited ankle rotation. This study is focused on the development of multi-rotational prosthetic foot for lower limb amputee. Our prosthesis is possible for amputees to easily walk in level ground by rotating ankle joint in sagittal plane and adapt to the abnormal terrain with ankle rotation in coronal plane. The resistance of ankle joint in the direction of dorsi/plantar-flexion can be manually regulated by hydraulic damper with controllable nozzle. Furthermore, double layered rubber induce the prosthesis adapt to irregular ground by tilting itself in direction of eversion and inversion. The experimental results highlights the potential that our prosthesis induce a normal gait for below knee amputee.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.2 no.1
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• pp.35-43
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• 2009

In this paper, we introduce a reading training program offering visual-auditory cue with noise cancellation function (RT program) developed by us. The RT program provides some training sentences with visual-auditory cues. Motor speech disorder patients can use the visual and/or auditory cues for reading training. To provide convenient estimation of training result, we developed a noise cancellation algorithm. The function of the algorithm is to remove noise and auditory-cues which are recorded with reading speech at the same time while patient read the sentences in PC monitor. In addition, we developed a function for finding out the first starting time of reading sound after a patient sees a sentence and begins to read the sentence. The recorded speeches are acquired from six people(three male, three female) in four noisy environments (interior noise, white noise, car interior noise, babble noise). We evaluated the timing error for starting time between original recorded speech and processed speech in condition of executing noise cancellation function and not executing. The timing error was improved as much as $4.847{\pm}2.4235[ms]$ as the effect of noise cancellation. It is expected that the developed RT program helps motor speech disorder patient in reading training and symptom evaluation.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.4
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• pp.275-283
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• 2015

This study was to find out the relationship between the rehabilitation service and the life satisfaction of industrially injured workers and how medical rehabilitation service, psycho-social rehabilitation service, and occupational rehabilitation service influence in this relation. For this, it analyzed 977 people who were using rehabilitation service with industrial disaster disability among 2,000 research subjects using the first year materials of industrial disaster insurance panel of Workers' Compensation & Welfare Service. For the relationship of variables on the suggested 3 models, the mediating effect of the occupational rehabilitation service in the relation of medical rehabilitation of the industrially injured workers and life satisfaction by applying SPSS Macro and Sobel method and did the regression analysis to find out the control effect of psycho-social rehabilitation service by the mean centering of the material. The result of the analysis showed; when the satisfaction on the medical rehabilitation service was increased the satisfaction on the voacational rehabilitation was increased, when the satisfaction on the occupational rehabilitation service was increased, the satisfaction on the life satisfaction was increased, and when the satisfaction on the psycho-social rehabilitation service was increased the medical rehabilitation service had a indirect effect on the daily life satisfaction.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.12 no.1
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• pp.1-9
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• 2018

This study is intended to identify how horseback riding affect the bone density of the elderly. A total of 31 normal senior citizens participated in the research, who were randomly divided into two groups: 15 in horseback riding exercise group and 16 in horseback riding machine exercise group. A horseback riding exercise program was carried out for 25 minutes twice a week for 12 weeks. A pre-test was conducted before starting the program and two post-tests were conducted 6 weeks and 12 weeks after exercises in the same way as the pre-test. Measured items were bone density of lumbar vertebrae and femur. In order to identify the changes in measurement variables before exercises and 6 weeks and 12 weeks after exercises, two-way repeated analysis of variance were used. The comparison of changes in the bone density in both groups revealed that there were significant differences in lumbar vertebrae L3, L4, femur trochanter in both groups over time. This study suggests that three-dimensional movements of horses through horseback riding exercises induce normal movements of senior citizens, providing positive effects on their bone density. If appropriate horse riding exercise programs are used considering the health status, time and economic conditions, and preferences of senior citizens, it would improve their quality of life.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.3
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• pp.185-193
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• 2015

The purpose of this study was to demonstrate clinical effects on cognition, visual perception, depression, anxiety, and activities of daily living by applying the N-BACK program, a brain stimulated training program, which is used for the clinical purpose. To prove this, subjects suspected of cognitive impairment with 18-23 points in a Korean version of mental status examination (MMSE-K) were recruited among the population who had been diagnosed with stroke duration and suffered from it for six months of duration, and 10 of the subjects were selected into the experimental group and the control group, respectively. A total of 20 sessions were carried out for 30 minutes per day 5 times for 4 weeks. As a result, the experimental group who has been applied the N-BACK program showed positive results in the improvement of cognition, visual perception, depression, anxiety, and daily living skills. The results obtained from this study expect us that applying the N-BACK program for the improvement of cognition, visual perception, depression, and anxiety to stroke patients has a positive effect on the rehabilitation of patients and will lead them to improve daily living activities more independently.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.4
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• pp.339-348
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• 2017

The purpose of this study was to verify the validity and reliability of the computerized general neurocognitive test using intuitive evaluation techniques to reflect the needs of the elderly and to validate neurocognitive function appropriately. The subjects were 100 elderly people who were over 60 healthy people. To evaluate the comprehensive neurocognitive function of the elderly, Computerized Neuro-cognitive Function Test (CNT, cybermedic. Co., Korea) developed by CyberMedic was used. The test consist of attention test, memory test and the problem solving ability test. As a result of correlation analysis of CNT test items, it was possible to confirm the characteristics of measuring single domain of attention and memory test. The problem-solving ability test also showed a high level of significant correlation, although the purpose of measurement was different, but a comprehensive cognitive function test for problem solving was possible. In the reliability analysis, the half reliability and internal consistency of test - retest were significantly higher. As a result of the above study, we conclude that the comprehensive neurocognitive test items constituted in this study have achieved reproducibility and effectiveness.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.4
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• pp.323-330
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• 2017

Knee sleeve has been used for prevention of sport injuries as well as rehabilitation. To investigate prevention of sport injuries of knee sleeve, it is important to evaluate balance associated with proprioception. The aim of this study was to evaluate the effects of a knee sleeve with a pad that stimulate to golgi tendon organ (GTO_PAD) on proprioception and balance ability. Five healthy males were participated for the study. They were asked to reenact target angle with Biodex and perform one leg standing with knee sleeve and knee sleeve with GTO_PAD. There was no significant difference in %Target angle, but the value of %Target angle was higher in subjects wearing knee sleeve with GTO_PAD than only knee sleeve, except for one subject. During one leg standing, time duration was increased in subjects wearing knee sleeve with GTO_PAD. The length of center of pressure in x-axis (COPx) and COP in y-axis (COPy) were decreased when wearing knee sleeve with GTO_PAD (COPx : $162.06{\pm}58.99mm$ in knee sleeve vs. $149.03{\pm}45.30mm$ in knee sleeve with GTO_PAD, COPy : $310.79{\pm}115.89mm$ in knee sleeve, $291.57{\pm}76.53mm$ in knee sleeve with GTO_PAD). There was significant differences in INI_transition, steady, and LAT_transition phase (all, p < 0.05). These findings support that wearing knee sleeve with GTO_PAD might enhance proprioception and balance.