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Organic photodetectors (OPDs) developed using novel semiconductor materials and well-designed device architectures have been rapidly progressing in recent years. In this article, we report the design, fabrication, and characterization of a high-performance OPD for detecting green light. The OPD is based on [Poly (3-hexylthiophene-2, 5-diyl)] (P3HT): PC61BM ([6], [6]-phenyl-C61-butyric acid methyl ester) active layer and an innovative hole transport layer (HTL) made from combination of polyethylenimine (PEI) interlayer and Copper (I) thiocyanate (CuSCN) interface layer. The innovative HTL significantly reduces the dark current and improves other optoelectronic properties of OPDs, including linear dynamic range (LDR) and specific detectivity. Results show that the newly designed OPDs have an extremely low dark current ( $\sim $ 100 pA), high detectivity ( $\sim $ 1013 Jones), and a large LDR of 180 dB. Compared to the conventional OPDs the newly designed OPDs show the capability to detect light at intensities two order of magnitude lower values. Application of the OPDs for photoplethysmography (PPG) sensing demonstrates that the newly designed photodetectors can successfully acquire PPG signal under ambient light condition without turning on any light-emitting diode (LED) and can have potential for development of low power PPG sensing wearables.

With the rapid development of advanced biomedical sensors, the Internet of Things, and modern wireless communication technologies, smart healthcare systems provide feasible solutions to the problems of population aging and telemedicine services. However, physiological information involves personal privacy, and the data security concern during the transmission of information on public channels has become a critical issue that has restricted the wider acceptance of smart healthcare systems. In this article, a secure and trustworthy smart healthcare system interoperating with wireless body area networks based on multistage blockchain is proposed. The security scheme provides a completely secure and trustworthy environment covering the entire data flow from the front-end to the back-end. The evaluation results show that the encryption scheme based on piecewise linear chaotic map can resist common attack methods and reduce encryption time. The system has the advantages of low complexity for encryption scheme, and larger capacity and efficiency for the blockchain-based data transmission and storage system.

The development in the field of advanced biomedical sensors has resulted in a large volume of data being collected and transmitted wirelessly. The IEEE 802.15.6-2012 standard has specified a communication protocol for body area networks, however existing general-purpose communication protocols such as Bluetooth and Zigbee are more widely used due to multiple reasons. One of the critical issues is the lack of baseband processing hardware modules that implement the aforementioned standard. In this paper, the authors propose a baseband transceiver implementation in ASIC, which meets the 802.15.6-2012 standard requirements. Compared to other published designs, the proposed implementation exhibits better performance and low hardware cost, while also offering a complete standard implementation.

Approximately, 21,000 breaths per day and 10.5 million breaths per year are taken by average people. Breathing functions depend on the actions of the respiratory muscles on the chest wall. This study analyzes the motions of the humans’ chest compartments with a portable, low-cost and convenient monitoring system to be used in e-health applications. Two wearable MEMS sensors are used to capture the rib cage (RC) and abdomen (AB) movements, simultaneously. In addition to measuring the phase shift between the chest wall compartments, the impacts of different body positions on AB and RC motions have been investigated on four different respiration patterns with ten subjects. The performance of the presented system is evaluated and the average mean square error of 0.13 is achieved for three time parameters including inspiratory, expiratory, and total time of the respiratory cycle. Moreover, the overall errors of phase shifts for paradoxical and synchronous breath patterns are 0.13° ± 0.12° and 0.21° ± 0.08°, respectively, considering two vernier respiration monitor belts as our references. The system properly indicates a significant increase in the degree of RC and AB asynchrony in the paradoxical breathing compared to normal pattern. To complete our platform, we propose a new “Breathing Therapy” technique as an advanced way to assist people to learn the science of breath and help the patients successfully restore their health in a systematic way. Graphical signs are used to provide feedback on the quality of each breath taken in real-time. The performance of the system is evaluated based on five well-known yogic breathing patterns.

Assertions are now widely used in verification as a means to help convey designer intent and also to simplify the detection of erroneous conditions by the firing of assertions. With this expressive modeling power, assertions could also be used for tasks such as helping to assess test coverage and even as a source for test generation. Our work deals with this last aspect, namely, assertion-based test generation. In this article, we present our compacted test generation scheme based on assertions. Novel compaction techniques are presented based on assertion clustering, test-path overlap detection and parallel-path removal. Our compaction approach is experimentally evaluated using nearly 300 assertions to show the amount of reduction that can be obtained in the size of the test sets. This ultimately has a positive impact on verification time in the quest for bugfree designs.

Assertion-based verification with languages such as PSL is gaining in importance. From assertions, one can generate hardware assertion checkers for use in emulation, simulation acceleration and silicon debug. We present techniques for checker generation of the complete set of PSL properties, including all variants of operators, both strong and weak. A full automata-based approach allows an entire assertion to be represented by a single automaton, hence allowing optimizations that can not be done in a modular approach where subcircuits are created only for individual operators. For this purpose, automata algorithms are developed for the base cases, and a complete set of rewrite rules is derived for other operators. Automata splitting is introduced for an efficient implementation of the eventually! operator.

This article details the use of an FPGA (Field Programmable Gate Array) to increase the playing strength of the chess-playing program MBChess. The FPGA is a user-reconfigurable logic device well suited to the development of complex digital circuits. In this application, the FPGA is used to perform hardware move generation with implicit move ordering, a time-consuming operation when performed in software. A simpler inter-square connection protocol reduces the number of wires between chess squares, when compared to the DeepBluedesign. The design also has the capability of generating checking moves separately, as well as indicating discovered checks: an important feature for good move ordering. Integration to the software’s transposition table and killer heuristic is demonstrated as well. The device is mounted on a card and inserted in the host computer where it is used as a coprocessor.