Biomedical subjects

Te-Son Kuo

Publications and source records attributed to Te-Son Kuo.

11 recordsLinked to original sources

PubMed2006

A remote data access architecture for home-monitoring health-care applications.

With the aging of the population and the increasing patient preference for receiving care in their own homes, remote home care is one of the fastest growing areas of health care in Taiwan and many other countries. Many remote home-monitoring applications have been developed and implemented to enable both formal and informal caregivers to have remote access to patient data so that they can respond instantly to any abnormalities of in-home patients. The aim of this technology is to give both patients and relatives better control of the health care, reduce the burden on informal caregivers and reduce visits to hospitals and thus result in a better quality of life for both the patient and his/her family. To facilitate their widespread adoption, remote home-monitoring systems take advantage of the low-cost features and popularity of the Internet and PCs, but are inherently exposed to several security risks, such as virus and denial-of-service (DoS) attacks. These security threats exist as long as the in-home PC is directly accessible by remote-monitoring users over the Internet. The purpose of the study reported in this paper was to improve the security of such systems, with the proposed architecture aimed at increasing the system availability and confidentiality of patient information. A broker server is introduced between the remote-monitoring devices and the in-home PCs. This topology removes direct access to the in-home PC, and a firewall can be configured to deny all inbound connections while the remote home-monitoring application is operating. This architecture helps to transfer the security risks from the in-home PC to the managed broker server, on which more advanced security measures can be implemented. The pros and cons of this novel architecture design are also discussed and summarized.

Ambulatory Care↗

PubMed2006

An effective and efficient compression algorithm for ECG signals with irregular periods.

This paper presents an effective and efficient preprocessing algorithm for two-dimensional (2-D) electrocardiogram (ECG) compression to better compress irregular ECG signals by exploiting their inter- and intra-beat correlations. To better reveal the correlation structure, we first convert the ECG signal into a proper 2-D representation, or image. This involves a few steps including QRS detection and alignment, period sorting, and length equalization. The resulting 2-D ECG representation is then ready to be compressed by an appropriate image compression algorithm. We choose the state-of-the-art JPEG2000 for its high efficiency and flexibility. In this way, the proposed algorithm is shown to outperform some existing arts in the literature by simultaneously achieving high compression ratio (CR), low percent root mean squared difference (PRD), low maximum error (MaxErr), and low standard derivation of errors (StdErr). In particular, because the proposed period sorting method rearranges the detected heartbeats into a smoother image that is easier to compress, this algorithm is insensitive to irregular ECG periods. Thus either the irregular ECG signals or the QRS false-detection cases can be better compressed. This is a significant improvement over existing 2-D ECG compression methods. Moreover, this algorithm is not tied exclusively to JPEG2000. It can also be combined with other 2-D preprocessing methods or appropriate codecs to enhance the compression performance in irregular ECG cases.

Algorithms↗

PubMed2005

The M3S-based electric wheelchair for the people with disabilities in Taiwan.

PURPOSE: This study aims to establish an electronic wheelchair system in Taiwan that conforms to multiple master-multiple slave (M3S) standards. The proposed system could enhance the safety and convenience of people with disabilities. MATERIAL AND METHOD: The M3S-based head-controlled electric wheelchair consists of three parts: (A) the input device, (B) the output device, and (C) the safety device. Head movement can be used as the input control to cause the tilting device to produce a corresponding level of analog voltage (backward & forward/left & right) which is then transmitted to the analogy/digital conversion module to control the output device (wheelchair's motor). Ten subjects with C5 incompleted spinal cord injury were recruited in the clinical assessment. They were randomly assigned into groups A and B. In the group A, the subjects were assigned to operate the head-controlled wheelchair system with M3S standard before operating the head-controlled wheelchair system without M3S standard. In the group B, the subjects were assigned to operate the head-controlled wheelchair system without M3S standard before operating the head-controlled wheelchair system with M3S standard. Two subjects in the group B drop off due to their personal reasons. RESULTS: The time cost for group A in completing tasks 1, 2, and 3 with the M3S and without the M3S were insignificant (p>0.05). The time cost for completing in group B was insignificant (p>0.05). Thus, the wheelchair operating time is depended on the proficiency of the subjects, not the M3S standard added. DISCUSSIONS AND CONCLUSIONS: The time cost for subjects to operate the wheelchair was determined by their proficiency, not the M3S standard control added to the system. However, the M3S-based system did realize the safety mechanism and complex auxiliary tools with and without the plug-in and play function.

Adult↗

PubMed2004

A laser micromachined probe for recording multiple field potentials in the thalamus.

Multichannel recording provides integral information about electrical brain activities at one instant in time. In this study, multielectrode probes were fabricated to record the thalamic field potentials (FPs) responding to the electrical stimulation of nerve at the rat tail. At first, the number of sweeps used to form the evoked FP average and the spatial sampling density were determined by using cross-correlation functions, which were then statistically analyzed. The difference was significant at P < 0.05, if the number of sweeps for averaging was more than 50 and the spatial interval between two consecutive recording sites was less than 50 microm in the anteroposterior, mediolateral and ventrodorsal directions. The responsive area was distributed vertically in the thalamus (ventral posterior lateral (VPL) nucleus); therefore, the recording sites were arranged in one linear array. Sixteen recording sites, which were 50 microm apart from each other, were distributed in the ventrodorsal direction. A 16-channel silicon probe was fabricated by using a standard photolithography process and laser micromachining techniques. The probe provides capabilities to record multiple thalamic evoked FPs and multiunit activities simultaneously.

Animals↗

PubMed2004

Infrared-based communication augmentation system for people with multiple disabilities.

PURPOSE: This study describes an eyeglass-type infrared-based communication board for the nonspeaking with quadriplegia. METHOD: This system is composed of four major components: a headset, an infrared transmitting module, an infrared receiving/signal-processing module, and a main controller, the Intel-8951 microprocessor. This design concept was based on the use of an infrared remote module fastened to the eyeglasses which could allow the convenient control of the input motion on the keys of a communication board, which are all modified with infrared receiving/signal-processing modules. For system evaluation, 12 subjects (all men, 21-45 years old, six normal subjects as the control group and six nonspeaking with quadriplegia as the experimental group) were recruited. RESULTS: The average accuracy of the control group and the experimental group were 93.1 +/- 4.3% and 89.7 +/- 5.5%, respectively. The average time cost of the control group and the experimental group were 78.3 +/- 8.7 s and 89.9 +/- 10.2 s, respectively. An independent t-test revealed that the differences in the average accuracy and the average time cost of the control group and the experimental group were not significant (p>0.05). CONCLUSIONS: The increase of opportunity to communicate using the infrared-based communication board would help people with multiple disabilities to socialize actively.

Adult↗

PubMed2004

The comparison of electromyographic pattern classifications with active and passive electrodes.

Electromyographic (EMG) signals are usually acquired using surface electrodes, and they commonly serve as the control sources of myoelectric prosthetic limbs. The use of passive electrodes and amplifiers with adjustable gain is very popular in laboratories for the development of new control strategies. However, active electrodes without conductive jelly are used in most clinical applications of myoelectric hand control. There remains an important question: Are there any differences between using active and passive electrodes in EMG pattern classifications? Autoregressive and cepstral coefficients were used to evaluate recognition rates via both types of electrodes. The results showed that the estimated recognition rates in the passive electrodes were comparable to those in the active ones (averaged recognition rate, 88.5 vs. 85.84% in the autoregressive coefficients, and 84.84 vs. 83.5%, in the cepstral coefficients, respectively). Aside from the lack of significant statistical differences between them, the results imply that the differences between the recognition rates via these electrodes could be negligible. This would be helpful for the myoelectric control of assistive devices.

Electrodes↗

PubMed2003

A head movement image (HMI)-controlled computer mouse for people with disabilities.

PURPOSE: This study proposes image processing and microprocessor technology for use in developing a head movement image (HMI)-controlled computer mouse system for the spinal cord injured (SCI). METHOD: The system controls the movement and direction of the mouse cursor by capturing head movement images using a marker installed on the user's headset. In the clinical trial, this new mouse system was compared with an infrared-controlled mouse system on various tasks with nine subjects with SCI. RESULTS: The results were favourable to the new mouse system. The differences between the new mouse system and the infrared-controlled mouse were reaching statistical significance in each of the test situations (p<0.05). CONCLUSIONS: The HMI-controlled computer mouse improves the input speed. People with disabilities need only wear the headset and move their heads to freely control the movement of the mouse cursor.

Communication Devices for People with Disabilities↗

PubMed2003

One-dimensional phased array with mechanical motion for conformal ultrasound hyperthermia.

This paper investigates the feasibility of conformal heating for external ultrasound hyperthermia by using a phased array transducer with mechanical motion. In this system, a one-dimensional phased array is arranged on a shaft and moves along the shaft, while dynamically focusing on the planning target volume (PTV) with numerous focal spots. To prevent overheating in the intervening tissue between the skin and the PTV, the shaft and the phased array are rotated together to enlarge the acoustical window. With the purpose of conformal heating, the power deposition of the PTV is constructed by combinations of the focal spots and an iterative gradient descent method is then used to determine an optimal set of power weightings for the focal spots. Different tumour shapes are evaluated and the simulation results demonstrate that the volume percentage of the PTV with temperatures higher than 43 degrees C is over 95%. The overheating volume outside the PTV is less than 25% of the PTV. This method provides good conformal heating for external ultrasound hyperthermia. The concept of combining electrical focusing and mechanical motion has the advantages of both enlarging the acoustic window and providing dynamic focusing ability, which is essential for successful conformal heating.

Body Temperature↗

PubMed2003

Combination of derived non-linear and linear methods to increase the reproducibility of transiently evoked otoacoustic emissions.

This paper proposes a segmented average method that combines the derived non-linear response (DNLR) and linear-averaging methods to increase the reproducibility of transiently evoked otoacoustic emissions (TEOAEs). In this method, the DNLR method is used at the 2.5-P-ms segment of each TEOAE signal, and the linear-averaging method is used from P to 20 ms. This exploits the reduced-artefact advantage of the DNLR method and the high-reproducibility advantage of the linear-averaging method. To evaluate the performance of the proposed method, 26 normal ears were tested, with P selected as 8 ms. Each TEOAE signal obtained was decomposed into three scales using the discrete wavelet transform. Then the similarities and differences between the signals obtained with this method and with the DNLR method were assessed. The results show that the average reproducibility of the TEOAE signals increases from 78.1%, to 88.7% when applying the proposed method.

Humans↗

PubMedDate not supplied

SEMG-controlled telephone interface for people with disabilities.

This paper proposes the development of a surface electromyographic (SEMG)-controlled telephone interface for the disabled. The system is composed of three major components: (1) a SEMG receiving/signal-processing module; (2) a row-column scanning interface for the telephone dialling pad; and (3) a main controller, the Intel-8951 microprocessor. The design concept was based on the idea of using a SEMG generated by the disabled and converting it into a trigger pulse. This could allow convenient control of the dialing motion in the row-column scanning keys of a telephone dialling pad. People with disabilities are competent for certain kinds of work such as being a telephone operator. The increase of opportunities to perform a job for the disabled would help them live independently.

Adult↗

PubMedDate not supplied

Neural network and fuzzy control in FES-assisted locomotion for the hemiplegic.

This study is aimed at establishing a neural network and fuzzy feedback control FES system used for adjusting the optimum electrical stimulating current to control the motion of an ankle joint. The proposed method further improves the drop-foot problem existing in hemiplegia patients. The proposed system includes both hardware and software. The hardware system determines the patient's ankle joint angle using a position sensor located in the patient's affected side. This sensor stimulates the tibialis anterior with an electrical stimulator that induces the dorsiflexion action and achieves the ideal ankle joint trace motion. The software system estimates the stimulating current using a neural network. The fuzzy controller solves the nonlinear problem by compensating the motion trace errors between the neural network control and actual system. The control qualities of various controllers for four subjects were compared in the clinical test. It was found that both the root mean square error and the mean error were minimal when using the neural network and fuzzy controller. The drop-foot problem in hemiplegic's locomotion was effectively improved by incorporating the neural network and fuzzy controller with the functional electrical simulator.

Algorithms↗