Wen-Tzeng Huang

Wireless Sensor Networks for Vital Signs Monitoring: Application in a Nursing Home

This study evaluated the application of a wireless sensor network (WSN) on a web-based vital signs monitoring system to nursing homes in Taiwan. The applicability assessment focused on the timely provision of information, information accuracy, system usability, and system accessibility of healthcare systems using a wireless sensor network. Experiments were performed under Internet-based network conditions to verify the timely information provision, especially for a web-based system, including Ajax technology. The accuracy of the information was verified from statistical analyses of the residents’ daily vital sign measurements. A comparison was performed between having and not having a healthcare monitoring system in nursing homes for system usability, system accessibility, and system efficacy. The results indicate that the successful application of a WSN healthcare monitoring system is feasible for use in nursing homes in Taiwan.

A compression layer for NAND type flash memory systems

Storage devices of embedded systems must have the characteristics of small size, great capacity, low-power consumption, lightweight, non-volatility, and vibration resistance. The NAND type flash memory, briefly denoted by NandFlash, is one of the more often-used storage devices. In terms of unit price, its cost is several dozen to hundred times more expensive than the traditional hard-disk (HD) since its storage space is limited. Therefore, to increase the storage space of NandFlash is great significance. In this paper, we improved the compression layer for NandFlash, which can be coordinated with the X-RL algorithm, to avoid overhead and reduce the degree of internal fragmentation in the compressed data pages. Hence, our proposed method can improve the compression rate. In the reading phase, we use the consecutive memory allocation method, which can reduce the superfluous time caused by non-consecutive access. Therefore, our architecture is meaningful and practical for embedded system applications.

Pancyclicity of Mobius cubes

The problem of containing pancyclic interconnection networks is an important research topic. An n-dimensional Mobius cube, MQ/sub n/, is a variant of hypercubes according to specific rules. In this paper, we prove that Mobius cubes are all pancyclic networks. Similarly, both an n-dimensional crossed cube, CQ/sub n/, and an n-dimensional twisted cube, TQ/sub n/, are also variants of hypercubes according to specific rules. Moreover although the pancyclic property of a crossed cube and a twisted cube had been proved, we propose an alternative proof of this property.

Concurrent error detection and correction in a polynomial basis multiplier over GF(2 m )

Finite-field arithmetic has been widely used to speed up the encryption and decryption processes in many cryptosystems, especially elliptic curve cryptosystems. Regular finite-field arithmetic structures are suitable for very large-scale integration implementation of cryptosystems, making them attractive for mobile commerce applications. Multiplication is the critical operation in finite-field arithmetic operations. Fault-based cryptanalysis is a new cryptanalysis method that deliberately injects faults into cryptographic devices, and requires only a small amount of side-channel information to break common ciphers. Thus, effective and simple methods for protecting the encryption/decryption circuitry from attackers are required to ensure that cryptographic devices can produce accurate signatures. This study presents a polynomial basis (PB) multiplier over GF(2m) with concurrent error detection (CED), and proposes a PB multiplier with concurrent error correction (CEC). A parallel structure of function cells is used in the proposed multiplier array to reduce the propagation delay. The proposed PB multiplier with internal parallel structure can reduce the time complexity by 28%, and reduce the space complexity by 90%, compared with existing PB multipliers. Compared with existing PB multipliers with CED, the proposed device with CED has a 20% greater space complexity but a 30% less time complexity. To the authors knowledge, there is no previous report of PB multipliers with CEC capability. The proposed PB multiplier with CEC capability has a space complexity of only about 10% more and requires five more clock cycles than the proposed device without CEC capability.

Development of Telemedicine and Telecare over Wireless Sensor Network

Telemedicine & Telecare aided by wireless sensor network (WSN) has recently become a health-caring trend in the future. However, the low data rate of WSN limited the acceptable quality of service. Researches [1-6] adopted ZigBee-based WSN to implement a platform and/or a telecare system. However, the capacity problem due to low data rate characteristic has not been addressed. Our research proposed an arrhythmia-aware telecare system and a new DSP-based WSN platform, enabling good digital signal processing performance in ZigBee-based WSN. Proved by simulations and several real tests, combination of the proposed platform and system can provide a more bandwidth-conserving and reliable telecare system, with lower wireless traffic jam and higher stability.

Using K-Nearest Neighbor Classification to Diagnose Abnormal Lung Sounds.

A reported 30% of people worldwide have abnormal lung sounds, including crackles, rhonchi, and wheezes. To date, the traditional stethoscope remains the most popular tool used by physicians to diagnose such abnormal lung sounds, however, many problems arise with the use of a stethoscope, including the effects of environmental noise, the inability to record and store lung sounds for follow-up or tracking, and the physician’s subjective diagnostic experience. This study has developed a digital stethoscope to help physicians overcome these problems when diagnosing abnormal lung sounds. In this digital system, mel-frequency cepstral coefficients (MFCCs) were used to extract the features of lung sounds, and then the K-means algorithm was used for feature clustering, to reduce the amount of data for computation. Finally, the K-nearest neighbor method was used to classify the lung sounds. The proposed system can also be used for home care: if the percentage of abnormal lung sound frames is > 30% of the whole test signal, the system can automatically warn the user to visit a physician for diagnosis. We also used bend sensors together with an amplification circuit, Bluetooth, and a microcontroller to implement a respiration detector. The respiratory signal extracted by the bend sensors can be transmitted to the computer via Bluetooth to calculate the respiratory cycle, for real-time assessment. If an abnormal status is detected, the device will warn the user automatically. Experimental results indicated that the error in respiratory cycles between measured and actual values was only 6.8%, illustrating the potential of our detector for home care applications.

Non-XOR approach for low-cost bit-parallel polynomial basis multiplier over GF(2 m )

Finite field arithmetic has been widely used in many cryptosystems, particularly in the elliptic curve cryptosystem (ECC) and the advanced encryption standard (AES) as a method for speeding up their encryption/decryption processes. Low-cost design for finite field arithmetic is more attractive for various mobile applications. It is a factor that a large number of Exclusive OR (XOR) gates have been used in the arithmetic operations under the traditional finite field arithmetic implementation. Thus, the cost of the traditional finite field arithmetic cannot be effectively lowered, because a typical XOR gate design consists of 12 transistors. To address this, a novel non-XOR approach consisting of eight transistors, for realising low-cost polynomial basis (PB) multiplier over GF(2 m ) was developed in this study. The authors proposed that non-XOR architecture for bit-parallel PB multiplier uses the multiplexer function instead of the traditional XOR function in its design. Based on the proposed non-XOR methodology, three popular low-cost irreducible polynomials - trinomial, pentanomial and all-one-polynomial - are proposed and designed in this study. The results indicate that the proposed non-XOR architecture can reduce space complexity by 22-, compared with that of the traditional design.

Fault Tolerance by Quartile Method in Wireless Sensor and Actor Networks

Recent technological advances have lead to the emergence of wireless sensor and actor networks (WSAN) which sensors gather the information for an event and actors perform the appropriate actions. Since sensors are prone to failure due to energy depletion, hardware failure, and communication link errors, designing an efficient fault tolerance mechanism becomes an important issue in WSAN. However, most research focus on communication link fault tolerance without considering sensing fault tolerance on paper survey. In this situation, actor may perform incorrect action by receiving error sensing data. To solve this issue, fault tolerance by quartile method (FTQM) is proposed in this paper. In FTQM, it not only determines the correct data range but also sifts the correct sensors by data discreteness. Therefore, actors could perform the appropriate actions in FTQM. Moreover, FTQM also could be integrated with communication link fault tolerance mechanism. In the simulation results, it demonstrates FTQM has better predicted rate of correct data, the detected tolerance rate of temperature, and the detected temperature compared with the traditional sensing fault tolerance mechanism. Moreover, FTQM has better performance when the real correct data rate and the threshold value of failure are varied.

The Real-Time Compression Layer for Flash Memory in Mobile Multimedia Devices

Flash memory is physically small, lightweight, nonvolatile, vibration resistant, and has high capacity and low power consumption. It has become an essential storage device in mobile multimedia products, such as mobile phones, digital cameras, and MP3 players. The compression technique can effectively increase capacity and reduce data transfer. Hence, we propose a mechanism that uses a packing agent and a ping-pong buffer to cooperate with the X-match and run-length compression/decompression algorithm to create a real-time compression layer. This mechanism does not create the internal fragmentation space that increases the compression ratio, which makes the reading response time stable, and it reduces the writing response time of the Yim et al method by 60%.

Bidirectional and Multi-User Telerehabilitation System: Clinical Effect on Balance, Functional Activity, and Satisfaction in Patients with Chronic Stroke Living in Long-Term Care Facilities

Background The application of internet technology for telerehabilitation in patients with stroke has developed rapidly. Objective The current study aimed to evaluate the effect of a bidirectional and multi-user telerehabilitation system on balance and satisfaction in patients with chronic stroke living in long-term care facilities (LTCFs). Method This pilot study used a multi-site, blocked randomization design. Twenty-four participants from three LTCFs were recruited, and the participants were randomly assigned into the telerehabilitation (Tele) and conventional therapy (Conv) groups within each LTCF. Tele group received telerehabilitation but the Conv group received conventional therapy with two persons in each group for three sessions per week and for four weeks. The outcome measures included Berg Balance Scale (BBS), Barthel Index (BI), and the telerehabilitation satisfaction of the participants. Setting A telerehabilitation system included “therapist end” in a laboratory, and the “client end” in LTCFs. The conventional therapy was conducted in LTCFs. Results Training programs conducted for both the Tele and Conv groups showed significant effects within groups on the participant BBS as well as the total and self-care scores of BI. No significant difference between groups could be demonstrated. The satisfaction of participants between the Tele and the Conv groups also did not show significant difference. Conclusions This pilot study indicated that the multi-user telerehabilitation program is feasible for improving the balance and functional activity similar to conventional therapy in patients with chronic stroke living in LTCFs.