Elhosary, Heba; Zakhari, Michael H.; ElGammal, Mohamed A.; Elghany, Mohamed Abd; Salama, Khaled N.; Mostafa, Hassan(IEEE Transactions on Biomedical Circuits and Systems, IEEE, 2019-10-14)[Article]
In this paper, a low power support vector machine (SVM) training, feature extraction, and classification algorithm are hardware implemented in a neural seizure detection application. The training algorithm used is the sequential minimal optimization (SMO) algorithm. The system is implemented on different platforms: such as field programmable gate array (FPGA), Xilinx Virtex-7 and application specific integrated circuit (ASIC) using hardware-calibrated UMC 65nm CMOS technology. The implemented training hardware is introduced as an accelerator intellectual property (IP), especially in the case of large number of training sets, such as neural seizure detection. Feature extraction and classification blocks are implemented to achieve the best trade-off between sensitivity and power consumption. The proposed seizure detection system achieves a sensitivity around 96.77% when tested with the implemented linear kernel classifier. A power consumption evaluation is performed on both the ASIC and FPGA platforms showing that the ASIC power consumption is improved by a factor of 2X when compared with the FPGA counterpart.
Yantir, Hasan Erdem; Guo, Wenzhe; Eltawil, Ahmed M; Kurdahi, Fadi J; Salama, Khaled N.(Micromachines, MDPI AG, 2019-08-03)[Article]
Current computation architectures rely on more processor-centric design principles. On the other hand, the inevitable increase in the amount of data that applications need forces researchers to design novel processor architectures that are more data-centric. By following this principle, this study proposes an area-efficient Fast Fourier Transform (FFT) processor through in-memory computing. The proposed architecture occupies the smallest footprint of around 0.1 mm 2 inside its class together with acceptable power efficiency. According to the results, the processor exhibits the highest area efficiency ( FFT / s / area ) among the existing FFT processors in the current literature.
Efficient carrier extraction is essential for high performance optoelectronic devices, such as solar cells and photodetectors. Conventional strategies to separate photogenerated carriers typically involve the fabrication of a p-n junction by doping and the use of carrier selective charge transport layers. However, these techniques often require high temperature processes or costly materials. In this work, we demonstrate an innovative and simple approach of extracting photogenerated carriers from organometallic halide perovskites utilizing triboelectricity. The triboelectric device can be easily fabricated at low temperature using inexpensive materials on plastic substrates, enabling it to be readily integrated into self-powered optoelectronic devices. As a proof-of-concept, we fabricated a triboelectrics-assisted perovskite photodetector, which enabled us to study the surface charges generated using different electrical contacts and bending conditions performed by the device. With the assistance of a triboelectric charge-induced electric field, the photocurrent and transient photoresponses were significantly enhanced. Furthermore, we integrated the plastic triboelectric device with a flexible photodetector to demonstrate this carrier collection approach in flexible/wearable electronics. To the best of our knowledge, this work is the first report of carrier extraction in organometallic halide perovskite photodetector by triboelectric charges, demonstrating a potential use for carrier extraction in other semiconductor-based optoeletronic devices.
Soliman, Shady; Jaela, Mohammed A.; Abotaleb, Abdelrhman M.; Hassan, Youssef; Abdelghany, Mohamed A.; Abdel-Hamid, Amr T.; Salama, Khaled N.; Mostafa, Hassan(Integration, Elsevier B.V., 2019-06-26)[Article]
Internet of Things (IoT) is a promising technology that is continuously spreading around the world leading to many challenges facing cryptographic designers who are trying to fulfill the security standards of IoT constrained devices. In this work, a new design is proposed that adds a new dimension of security by using the concept of frequency hopping to generate a pseudo-random pattern for switching between 5 lightweight cryptographic ciphers: AEGIS, ASCON, COLM, Deoxys and OCB that are participating in the Competition for Authenticated Encryption, Security, Applicability, and Robustness (CAESAR). The proposed design exploits the advantages of Dynamic Partial Reconfiguration (DPR) technology in Field Programmable Gate Arrays (FPGAs) to switch between the 5 ciphers using Internal Configuration Access Port controller (AXI-HWICAP) providing a decrease of 58% and 80% in area utilization and power consumption respectively. The design is synthesized using Xilinx Vivado 2015.2 and mounted on Zynq evaluation board (XC7Z020LG484-1).
Ahmad, Rafiq; Majhi, Sanjit Manohar; Zhang, Xixiang; Swager, Timothy M.; Salama, Khaled N.(Advances in Colloid and Interface Science, Elsevier BV, 2019-05-22)[Article]
Vertically oriented zinc oxide (ZnO) nanomaterials, such as nanorods (NRs), nanowires (NWs), nanotubes (NTs), nanoneedles (NNs), and nanosheets (NSs), are highly ordered architectures that provide remarkable properties for sensors. Furthermore, these nanostructures have fascinating features, including high surface-area-to-volume ratios, high charge carrier concentrations, and many surface-active sites. These features make vertically oriented ZnO nanomaterials exciting candidates for gas sensor fabrication. The development of efficient methods for the production of vertically oriented nanomaterial electrode surfaces has resulted in improved stability, high reproducibility, and gas sensing performance. Moving beyond conventional fabrication processes that include binders and nanomaterial deposition steps has been crucial, as the materials from these processes suffer from poor stability, low reproducibility, and marginal sensing performance. In this feature article, we comprehensively describe vertically oriented ZnO nanomaterials for gas sensing applications. The uses of such nanomaterials for gas sensor fabrication are discussed in the context of ease of growth, stability on an electrode surface, growth reproducibility, and enhancements in device efficiency as a result of their unique and advantageous features. In addition, we summarize applications of gas sensors for a variety of toxic and volatile organic compound (VOC) gases, and we discuss future directions of the vertically oriented ZnO nanomaterials.
The development of self-powered electronic systems requires integration of on-chip energy-storage units to interface with various types of energy harvesters, which are intermittent by nature. Most studies have involved on-chip electrochemical microsupercapacitors that have been interfaced with energy harvesters through bulky Si-based rectifiers that are difficult to integrate. This study demonstrates transistor-level integration of electrochemical microsupercapacitors and thin film transistor rectifiers. In this approach, the thin film transistors, thin film rectifiers, and electrochemical microsupercapacitors share the same electrode material for all, which allows for a highly integrated electrochemical on-chip storage solution. The thin film rectifiers are shown to be capable of rectifying AC signal input from either triboelectric nanogenerators or standard function generators. In addition, electrochemical microsupercapacitors exhibit exceptionally slow self-discharge rate (≈18.75 mV h-1 ) and sufficient power to drive various electronic devices. This study opens a new avenue for developing compact on-chip electrochemical micropower units integrated with thin film electronics.
In this work, we present a highly sensitive and selective capacitive humidity sensor. Trianglamine hydrochloride is used as the sensing material, which is synthesized by a [3+3] cyclocondensation reaction between terpthaldehyde and 1R,2R-cyclohexanediamine followed by addition of hydrochloric acid and vapor diffusion of acetone. The crystalline trianglamine hydrochloride salts are dispersed in acetonitrile and then coated on interdigitated electrode substrates by drop casting. The sensor response is characterized for relative humidity (RH) ranging from 5% to 95%. The sensor has a nonlinear response, where the sensitivity increases with an increase in RH. The sensor demonstrates, on average, normalized sensitivities of 0.015 and 6.9 per percent of RH below and above 65% RH, respectively. In addition, the sensor is characterized for hysteresis, long-term stability, effect of temperature, and selectivity. The hysteresis of the sensor is a maximum of about 20% RH and is stable for over 25 days. Temperature analysis of the sensors shows that the sensitivity decreases with increase in temperature. The material is shown to be highly selective with respect to volatile organic compounds (VOCs) and toxic/corrosive gasses. Overall, trianglamine hydrochloride is a promising material for developing a highly sensitive and selective capacitive transduction-based humidity sensor.
Ismail, Aya A.; Shaheen, Zeinab A.; Rashad, Osama; Salama, Khaled N.; Mostafa, Hassan(2018 30th International Conference on Microelectronics (ICM), Institute of Electrical and Electronics Engineers (IEEE), 2019-05-02)[Conference Paper]
This paper introduces the hardware implementation of one of the most popular spiking neuron models which is Izhikevich model. The main target of this implementation is to reduce area and power consumed by the Spiking Neural Network (SNN) neurons as the SNN consists of a large number of neurons to mimic the human brain. Therefore, stochastic computing techniques are used to perform the squaring term that consumes much of the power in the Izhikevich neuron model equations. A hardware implementation of the model is proposed to show the area and power consumption to help the SNN designers to choose between stochastic-based multipliers and the approximate multipliers considering their power, area, and accuracy constraints.
Sivashankar, Shilpa; Alamoudi, Kholod; Agambayev, Sumeyra; Mashraei, Yousof; Mkaouar, Hend; Khashab, Niveen M.; Salama, Khaled N.(2018 30th International Conference on Microelectronics (ICM), Institute of Electrical and Electronics Engineers (IEEE), 2019-05-02)[Conference Paper]
To date, although microfabrication technologies for fabricating a microfluidic device are advanced, they are still time-consuming and laborious. Hence, we demonstrate the fabrication of microfluidic devices with a fast and easy maskless Ultraviolet (UV) projection method based on a stereolithography process in less than 5 mins. The flow model analysis by COMSOL gives the design concept of the gradient demonstrated. The fabricated chip is a miniaturized 25×25 mm2 gradient chip that produces gradient by maintaining equal width and length of each channel throughout the device. The design of the gradient is dependent on diffusion of molecules and hence is well suited for low flow rate applications such as drug delivery or cell related studies. The biocompatibility of the resins in their native form and with surface modification was evaluated by injecting cell culture medium to culture Human cervical cell line (HeLa) cells. Drug (Doxorubicin) screening was demonstrated by the viability of HeLa cells using Cell Counting Kit-8 (CCK-8) calorimetric assay. The miniaturized size of the chip aids these gradient generators to find applications in drug testing Lab-on-chip/Micro Total analysis systems (μTAS) and organ-on-chip devices.
Farhat, Mohamed; Guenneau, S.; Chen, P. Y.; Alù, A.; Salama, Khaled N.(Physical Review Applied, American Physical Society (APS), 2019-04-29)[Article]
We theoretically propose scattering cancellation-based cloaks for heat waves that obey the Maxwell-Cattaneo equation. The proposed cloaks possess carefully tailored diffusivity to cancel the dipole scattering from the object that they surround, and thus can render a small object invisible in the near and far fields, as demonstrated by full-wave finite-element simulations. Mantle heat cloaking is further analyzed and proposed to simplify the design and bring this cloaking technology one step closer to its practical implementation, with promising applications in nanoelectronics and defense-related applications.
The export option will allow you to export the current search results of the entered query to a file. Different
formats are available for download. To export the items, click on the button corresponding with the preferred download format.
By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.
For anonymous users the allowed maximum amount is 50 search results.
To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export.
The amount of items that can be exported at once is similarly restricted as the full export.
After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.