A design and implementation of fully programmable switched-currentIIR filters

An approach to switched-current filter design based on digital multiply-accumulator and delay blocks is presented. The characteristics of the filter are made fully programmable by simply changing the ratios of the coefficient transistors. To reduce the effect of switch charge injection and channel-length modulation, a high-performance, single-ended differential, switched-current memory cell is developed and used as a basic building block. To reduce the chip area and to maintain the required accuracy of the coefficients, an array consisting of three different sizes of transistors is designed instead of using a unit transistor array as coefficient transistors. An experimental prototype infinite impulse response filter array consisting of six second-order switched-current sections is designed and fabricated with a standard 1.2-μ CMOS process technology. A hard-wiring technique is used to program the filters. The test results show that the characteristics of the filters satisfy the design requirements     

Double-pass L-band EDFA with enhanced noise figure characteristics

A new double-pass long wavelength band erbium-doped fiber amplifier with enhanced noise figure characteristics is demonstrated by adding a short length of forward pumped erbium-doped fiber (EDF) in front of a double-pass amplifier. Compared with the conventional double-pass amplifier, the new amplifier provides noise figure improvement of about 0.8 to 6.0 dB over the flat-gain region from 1568 to 1600 nm. Since the optical circulator prevents the amplified signal and backward amplified spontaneous emission from propagating into the EDF, the population inversion of the input part of the amplifier is hardly affected by the intense lights, therefore, the noise figure could be kept low. The new double-pass system has achieved a flat-gain output at about 33.5 dB, which is 13.5 dB higher than that of the single-pass system with gain variation less than 1.3 dB at the flat-gain region. The noise figure varies from 5.9 to 6.6 dB in this region.     

Broad-band SiGe MMICs for phased-array radar applications

This paper reports the performances of several broad-band monolithic SiGe monolithic microwave integrated circuits (MMICs) suitable for phased-array radar applications. The amplitude and phase control MMIC designs are based on an optimized SiGe p-i-n diode offered by the IBM 5HP SiGe foundry process. Utilizing this diode, several control circuitries including a broad-band (1-20-GHz) monolithic single-pole double-throw switch, a five-port transfer switch, a 6-bit phase shifter, and a 5-bit attenuator, all operating over 7-11 GHz, are designed. Also, the design and performance of an SiGe heterojunction bipolar transistor variable-gain cascode amplifier that combines the functionality of an amplifier and an attenuator into one MMIC is described.     

Engineering Iron Oxide Hollow Nanospheres to Enhance Antimicrobial Property: Understanding the Cytotoxic Origin in Organic Rich Environment

Engineered magnetic iron oxide nanoparticles with surprisingly high antimicrobial activity and excellent safety profiles to mammalian cell lines have been developed. Hematite hollow nanospheres (HNSs) are prepared by a facile hard templating method; reduction of hematite HNSs by H₂ leads to magnetite HNSs. The antimicrobial activity of magnetite HNSs towards Gram negative (Escherichia coli) and Gram positive (Staphylococcus epidermidis) bacteria is evaluated against hematite HNSs and conventional magnetite (C‐magnetite; diameter <50 nm). Superior antibacterial performance is observed for magnetite HNSs towards both E. coli and S. epidermidis over hematite HNSs and C‐magnetite. The origin of the antimicrobial activity of magnetite HNSs is the high leaching of iron ions in the presence of microorganisms, which leads to high generation of reactive oxygen species. Magnetite HNSs allow multiple‐fold increase in the generation of soluble iron ions over hematite HNSs and C‐magnetite, showing that control over both the composition and nanostructure is crucial to tune the antimicrobial activity of iron oxides. Based on the current findings, magnetic HNSs show promising potential antimicrobial applications.     

A low-overhead and reliable switch architecture for Network-on-Chips

This paper proposes and evaluates Low-overhead, Reliable Switch (LRS) architecture to enhance the reliability of Network-on-Chips (NoCs). The proposed switch architecture exploits information and hardware redundancies to eliminate retransmission of faulty flits. The LRS architecture creates a redundant copy of each newly received flit and stores the redundant flit in a duplicated flit buffer that is associated with the incoming channel of the flit. Flit buffers in the LRS are equipped with information redundancy to detect probable bit flip errors. When an error is detected in a flit buffer, its duplicated buffer is used to recover the correct value of the flit. In this way, the propagation of the erroneous flits in NoC is prevented without any need to credit signals and, retransmission buffers. Using an HDL-based NoC simulator, the LRS is compared to two other widely used reliability enhancement methods: the Switch-to-Switch (S2S) and the End-to-End (E2E) methods. The simulation results show that the LRS consumes less power and provides higher performance compared to those of the E2E and S2S methods. More importantly, unlike the E2E and the S2S methods, the LRS has constant overheads, which makes it applicable in all working conditions. To validate the comparison, an analytical performance and reliability model is developed for the LRS, S2S and E2E methods. The results of the model match those obtained from the simulations while the proposed model is significantly faster.     

Characterization of vanadyl phthalocyanine based surface-type capacitive humidity sensors

This study presents the fabrication and characterization of novel surface-type capacitive humidity sensors using vanadyl phthalocyanine (VOPc) as the active material. The devices, which comprise three different thicknesses,have been fabricated using the thermal evaporation technique. A thin film of VOPc is deposited on thoroughly cleaned glass substrates with pre-pattemed Ag electrodes. The capacitive effect of the samples under humidity has been in-vestigated. Comparison of the samples with different thicknesses shows that the thinnest device seems more sensitive towards humidity. The humidity dependent capacitance properties of the sensor make it beneficial for use in commercial hygrometers.     

Second harmonic generation from LB superlattices containing two active components

Second harmonic generation has been observed from Langmuir-Blodgett multilayer arrays containing two active components. Both materials were based on long chain donor-acceptor dye compounds, but were designed with the donor-acceptor groups in opposite senses with respect to the hydrocarbon chain. Preliminary results indicate a significant enhancement of the second-order polarisability for this type of supermolecular array.     

Establishment of traceability for strain measuring data acquisition system in terms of voltage

This paper emphasizes on establishment of traceability for the strain measuring data acquisition system in terms of voltage. If this amplifier’s output voltage is not calibrated then traceability chain breaks. To complete the traceability chain, the amplifier’s output voltage has been calibrated for corresponding strain. The sensitivity is calculated using calibration results and further used to feed in data acquisition system to display the result in terms of force/strain.     

A Service Level Agreement Aware Online Algorithm for Virtual Machine Migration

The demand for cloud computing has increased manifold in the recent past. More specifically, on-demand computing has seen a rapid rise as organizations rely mostly on cloud service providers for their day-to-day computing needs. The cloud service provider fulfills different user requirements using virtualization - where a single physical machine can host multiple Virtual Machines. Each virtual machine potentially represents a different user environment such as operating system, programming environment, and applications. However, these cloud services use a large amount of electrical energy and produce greenhouse gases. To reduce the electricity cost and greenhouse gases, energy efficient algorithms must be designed. One specific area where energy efficient algorithms are required is virtual machine consolidation. With virtual machine consolidation, the objective is to utilize the minimum possible number of hosts to accommodate the required virtual machines, keeping in mind the service level agreement requirements. This research work formulates the virtual machine migration as an online problem and develops optimal offline and online algorithms for the single host virtual machine migration problem under a service level agreement constraint for an over-utilized host. The online algorithm is analyzed using a competitive analysis approach. In addition, an experimental analysis of the proposed algorithm on real-world data is conducted to showcase the improved performance of the proposed algorithm against the benchmark algorithms. Our proposed online algorithm consumed 25% less energy and performed 43% fewer migrations than the benchmark algorithms.     

Automated Patient Discomfort Detection Using Deep Learning

The Internet of Things (IoT) has been transformed almost all fields of life, but its impact on the healthcare sector has been notable. Various IoT-based sensors are used in the healthcare sector and offer quality and safe care to patients. This work presents a deep learning-based automated patient discomfort detection system in which patients’ discomfort is non-invasively detected. To do this, the overhead view patients’ data set has been recorded. For testing and evaluation purposes, we investigate the power of deep learning by choosing a Convolution Neural Network (CNN) based model. The model uses confidence maps and detects 18 different key points at various locations of the body of the patient. Applying association rules and part affinity fields, the detected key points are later converted into six main body organs. Furthermore, the distance of subsequent key points is measured using coordinates information. Finally, distance and the time-based threshold are used for the classification of movements associated with discomfort or normal conditions. The accuracy of the proposed system is assessed on various test sequences. The experimental outcomes reveal the worth of the proposed system’ by obtaining a True Positive Rate of 98% with a 2% False Positive Rate.