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The pole-phase modulated induction motor (PPMIM) drives facilitate the extended range of speed-torque characteristics, which is an essential requirement for traction and electric vehicle applications. For getting the wider speed-torque variations, $15-\Phi $ PPMIM drive is analyzed, which is capable to operate at 2-pole 15-phase, 6-pole 5-phase, and 10-pole 3-phase modes. In these pole-phase operations, in high-phase and low-pole mode of operation, the increment in the linear modulation range with space vector pulsewidth modulation (SVPWM) is not significant. In the low-phase and high-pole mode of operation, there will be higher torque ripples due to the higher magnitude of space harmonics. In this paper, these issues are addressed by using carrier phase-shifted SVPWM (CPS-SVPWM) and phase grouping concepts. In low-pole operation, the linear modulation is enriched by using conventional $3-\Phi $ SVPWM to drive 15-phase machine by appropriately reorganizing the phase winding connections. Similarly, in 6-pole 5-phase mode of operation, the linear modulation range of PPMIM drive is enriched by using $5-\Phi $ SVPWM. It is known that in high-pole mode of PPMIM drive operation, each effective phase is formed by the multiple number of equal voltage potential coils (EVPCs), which are electrically in phase. The carriers of these EVPCs per phase are phase shifted by an appropriate angle to minimize the harmonics in the effective phase voltage, which results in better torque ripple profile. In addition, the detailed comparison of three possible different CPS-SVPWMs is presented, with their pros and cons for selecting the proper carrier phase shift angle. The performance of the proposed scheme has been validated by ANSYS Maxwell two-dimensional as well as laboratory prototype on 5-hp, $15-\Phi $ PPMIM drive.

We consider network coding for a noiseless broadcast channel, where each receiver demands a subset of the messages available at the transmitter and is equipped with noisy side information in the form of an erroneous version of the message symbols it demands. We view the message symbols as elements from a finite field and assume that the number of symbol errors in the noisy side information is upper bounded by a known constant. This communication problem, which we refer to as broadcasting with noisy side information (BNSI) , has applications in the re-transmission phase of downlink networks. We derive a necessary and sufficient condition for a linear coding scheme to satisfy the demands of all the receivers in a given BNSI network, and show that syndrome decoding can be used at the receivers to decode the demanded messages from the received codeword and the available noisy side information. We represent BNSI problems as bipartite graphs, and using this representation, classify the family of problems, where linear coding provides bandwidth savings compared to uncoded transmission. We provide a simple algorithm to determine if a given BNSI network belongs to this family of problems, i.e., to identify if linear coding provides an advantage over uncoded transmission for the given BNSI problem. We provide lower bounds and upper bounds on the optimal codelength and constructions of linear coding schemes based on linear error correcting codes. For any given BNSI problem, we construct an equivalent index coding problem. A linear code is a valid scheme for a BNSI problem if and only if it is valid for the constructed scalar linear index coding problem.

In this brief, we propose a low-complexity design methodology to compute square-root and division using circular coordinate rotation digital computer (CORDIC). Unlike the state of the art methods, the proposed methodology eliminates the requirement of a separate hardware for square root and division computation in the CORDIC-based applications without compromising the computational speed, throughput and accuracy. The ASIC implementation of the proposed architecture has been performed using UMC 90 nm Technology node with 1.08 V @1 MHz and subsequently Xilinx Virtex-6 (XC6v1x240t)-based FPGA-prototyping has been done. The performance of the proposed methodology has been compared with the reported literature and significant power consumption improvement was observed without any additional area overhead.

A fixed dimensional representation for action clips of varying lengths has been proposed in the literature using aggregation models like bag-of-words and Fisher vector. These representations are high dimensional and require classification techniques for action recognition. In this paper, we propose a framework for unsupervised extraction of a discriminative low-dimensional representation called action-vector. To start with, local spatio-temporal features are utilized to capture the action attributes implicitly in a large Gaussian mixture model called the universal attribute model (UAM). To enhance the contribution of the significant attributes in each action clip, a maximum aposteriori adaptation of the UAM means is performed for each clip. This results in a concatenated mean vector called super action vector (SAV) for each action clip. However, the SAV is still high dimensional because of the presence of redundant attributes. Hence, we employ factor analysis to represent every SAV only in terms of the few important attributes contributing to the action clip. This leads to a low-dimensional representation called action-vector. This entire procedure requires no class labels and produces action-vectors that are distinct representations of each action irrespective of the inter-actor variability encountered in unconstrained videos. An evaluation on trimmed action datasets UCF101 and HMDB51 demonstrates the efficacy of action-vectors for action classification over state-of-the-art techniques. Moreover, we also show that action-vectors can adequately represent untrimmed videos from the THUMOS14 dataset and produce classification results comparable to existing techniques.

Multicasting $K$ independent messages via multiple-input multiple-output channels to multiple users where each user already has a subset of messages as side information is studied. A general framework of constructing layered space-time index coding (LSTIC) from a large class of space-time block codes (STBC), including perfect STBC, is proposed. We analyze the proposed LSTIC and show that it provides minimum determinant gains that are exponential with the amount of information contained in the side information for any possible side information . When constructed over a perfect STBC, the proposed LSTIC is itself a perfect STBC and hence many desired properties are preserved. To illustrate, we construct LSTIC over the following well-known STBCs: Golden code; $3\times 3$ , $4\times 4$ , and $6\times 6$ perfect STBCs; and Alamouti code. Simulation results show that the obtained side information gain can be well predicted by our analysis.

This paper presents a multilevel inverter (MLI) configuration for open-end-winding pole-phase-modulated-multiphase induction motor (PPMMIM) drives. The proposed MLI configuration consists of one nine-phase two-level inverter and three 3-Φ two-level inverters. In pole–phase modulation, increasing the number of poles decreases the number of phases that increases the space harmonics in air gap flux. Moreover, in high-pole mode of PPMMIM drives, two-level voltage supply causes the high torque ripple that degrades the performance of the drive. Usually, conventional MLIs are not preferred for reducing torque ripple, due to the capacitor-balancing issues and more number of semiconductor devices. To address these issues, the proposed MLI configuration effectively utilized the inherent availability of the three identical voltage coils in the high-pole mode for reducing the torque ripple. The 3-Φ carrier phase-shifted space vector pulse width modulation (SVPWM) is used for generating the multistep voltage across the effective phase in high-pole mode as well as for shifting the lower order harmonics to higher order frequencies. Moreover, in low-pole mode, the dc-link voltage utilization of the proposed MLI configuration is improved by 13.8% with third harmonic injected SVPWM as compared to conventional 9-Φ SVPWM. Another important feature of the proposed MLI configuration is its ability to supply the two-level voltage under fault conditions. This feature notably improves the reliability of the PPMMIM drive. The finite-element method model of 5-hp nine-phase PPMMIM is designed in ANSYS Maxwell 2-D and is cosimulated with the proposed MLI configuration in Simplorer environment. The effectiveness of the proposed MLI-fed 5-hp MIM drive is experimentally verified for the entire modulation range.

Surface electromyography (sEMG) data acquired during lower limb movements has the potential for investigating knee pathology. Nevertheless, a major challenge encountered with sEMG signals generated by lower limb movements is the intersubject variability, because the signals recorded from the leg or thigh muscles are contingent on the characteristics of a subject such as gait activity and muscle structure. In order to cope with this difficulty, we have designed a three-step classification scheme. First, the multichannel sEMG is decomposed into activities of the underlying sources by means of independent component analysis via entropy bound minimization. Next, a set of time-domain features, which would best discriminate various movements, are extracted from the source estimates. Finally, the feature selection is performed with the help of the Fisher score and a scree-plot-based statistical technique , prior to feeding the dimension-reduced features to the linear discriminant analysis . The investigation involves 11 healthy subjects and 11 individuals with knee pathology performing three different lower limb movements, namely, walking, sitting, and standing, which yielded an average classification accuracy of 96.1% and 86.2%, respectively. While the outcome of this study per se is very encouraging, with suitable improvement, the clinical application of such an sEMG-based pattern recognition system that distinguishes healthy and knee pathological subjects would be an attractive consequence.

Lattices possess elegant mathematical properties which have been previously used in the literature to show that structured codes can be efficient in a variety of communication scenarios, including coding for the additive white Gaussian noise channel, dirty-paper channel, Wyner–Ziv coding, coding for relay networks, and so forth. We consider the family of single-transmitter multiple-receiver Gaussian channels, where the source transmits a set of common messages to all the receivers (multicast scenario), and each receiver has coded side information , i.e., prior information in the form of linear combinations of the messages. This channel model is motivated by applications to multi-terminal networks, where the nodes may have access to coded versions of the messages from previous signal hops or through orthogonal channels. The capacity of this channel is known and follows from the work of Tuncel (2006), which is based on random coding arguments. In this paper, following the approach of Erez and Zamir, we design lattice codes for this family of channels when the source messages are symbols from a finite field $\mathbb {F}_{p}$ of prime size. Our coding scheme utilizes Construction A lattices designed over the same prime field $\mathbb {F}_{p}$ , and uses algebraic binning at the decoders to expurgate the channel code and obtain good lattice subcodes, for every possible set of linear combinations available as side information. The achievable rate of our coding scheme is a function of the size $p$ of underlying prime field, and approaches the capacity as $p$ tends to infinity.

In this brief, we propose a low-complexity methodology to compute a complex square root using only a circular coordinate rotation digital computer (CORDIC) as opposed to the state-of-the-art techniques that need both circular as well as hyperbolic CORDICs. Subsequently, an architecture has been designed based on the proposed methodology and implemented on the ASIC platform using the UMC 180-nm Technology node with 1.0 V at 5 MHz. Field programmable gate array (FPGA) prototyping using Xilinx’ Virtex-6 (XC6v1x240t) has also been carried out. After thorough theoretical analysis and experimental validations, it can be inferred that the proposed methodology reduces 21.15% slice look up tables (on FPGA platform) and saves 20.25% silicon area overhead and decreases 19% power consumption (on ASIC platform) when compared with the state-of-the-art method without compromising the computational speed, throughput, and accuracy.

Here, we report a grapheme–polyaniline (Gr-PANi) composite modified glassy carbon electrode (GCE) as an amperometric pH sensor. Gr-PANi composite was synthesized by electro-deposition of PANi on the surface of Gr modified GCE using the cyclic voltammetry technique. XRD and Raman analysis confirmed high crystallinity of Gr-PANi composite. FESEM analysis revealed that Gr flakes are surrounded by PANi film because of the heterogeneous nucleation and growth of PANi during electro-polymerization. In acidic region, current of the composite-based pH sensor increased with decreasing pH values of the solution, whereas in alkaline region, current increased with the increasing pH values of the solution. The as-fabricated pH sensor exhibits shorter response time with an excellent sensitivity of - $50.14~\mu \text{A}$ pH−1 cm $^{-2}$ in the range of pH 1–5 and $139.2~\mu \text{A}$ pH−1 cm $^{-2}$ in the range of pH 7–11. The composite-based sensor showed enhanced sensitivity compared with pure Gr-based pH sensor because unlike pristine Gr-based pH sensor, it utilizes both charge-storage mechanisms in EDLCs and pseudo-capacitors, thereby resulting in excellent synergy between Gr and PANi. Reproducibility of the pH sensor was also examined between three different electrodes in the solution of pH 5. Insignificant variation in the current response suggested excellent reproducibility of pH sensor. To the best of our knowledge, no other studies have been reported on the Gr-PANi composite-based pH sensor over wide pH range. This Gr-PANi-based pH sensor offers a simple, low-cost, promising, real-time amperometric pH sensor in chemistry, clinical diagnostics, bio-sensing, and environmental monitoring applications.

Line-of-sight (LoS) multiple-input multiple-output (MIMO) gives full spatial-multiplexing gain when the antenna array geometry and orientation are designed based on the interterminal distance. These known design methodologies that hold for antenna arrays with fixed orientation do not provide full MIMO gains for arbitrary array orientations. In this paper, we study LoS MIMO channels with random array orientations when the number of transmit antennas used for signaling is 2. We study the impact of common array geometries on error probability, and identify the code design parameter that describes the high signal-to-noise ratio (SNR) error performance of an arbitrary coding scheme. For planar receive arrays, the error rate is shown to decay only as fast as that of a rank 1 channel, and no better than SNR $^{-3}$ for a class of coding schemes that includes spatial multiplexing. We then show that for the tetrahedral receive array, which uses the smallest number of antennas among nonplanar arrays, the error rate decays faster than that of rank 1 channels and is exponential in SNR for every coding scheme. Finally, we design a LoS MIMO system that guarantees a good error performance for all transmit/receive array orientations and over a range of interterminal distances.

In this paper, a fault-tolerant single-phase five-level inverter configuration is proposed for photovoltaic (PV) generation systems. Conventional two-level inverters are popularly used in PV applications, but these inverters provide the output voltage with considerable harmonic content. One of the efficient ways to improve the power quality of PV generation systems is to replace a two-level inverter with a multilevel inverter. Conventional multilevel inverters reduce total harmonic distortion and filter requirements effectively, but it has limitations in terms of reliability due to increased device count and capacitor voltage balancing issues. Therefore, a fault-tolerant single-phase five-level inverter is presented, which is constructed by using a half-bridge two-level inverter, a three-level diode clamp inverter, and a bidirectional switch. The proposed inverter topology can tolerate the system faults due to failure of the source and/or switching devices with least modification in the switching combinations. It has less number of switching devices compared to conventional five-level inverters. The topology also has the energy-balancing capability between sources which helps in reducing uneven charge of batteries in case of partial shading or hotspots on one side of the PV panels. The proposed system under normal and faulty condition is simulated in MATLAB/Simulink environment, and results are verified with a laboratory prototype.

The phase spectrum of Fourier transform has received lesser prominence than its magnitude counterpart in speech processing. In this paper, we propose a method for parametric modeling of the phase spectrum, and discuss its applications in speech signal processing. The phase spectrum is modeled as the response of an allpass (AP) filter, whose coefficients are estimated from the knowledge of speech production process, especially the impulse-like nature of excitation source. A signal retaining only the phase spectral component of speech signal is derived by suppressing the magnitude spectral component, and is modeled as the output of an AP filter excited with a sequence of impulses. Entropy of energy of the input signal is minimized to estimate the coefficients of the AP filter. The resulting objective function, being nonconvex in nature, is minimized using particle swarm optimization. The group delay response of estimated AP filters can be used for accurate analysis of resonances of the vocal-tract system (VTS). The error signal associated with AP modeling provides unambiguous evidence about the instants of significant excitation of the VTS. The applications of the proposed AP modeling include, but not limited to, formant tracking, extraction of glottal closure instants, speaker verification and speech synthesis.

The index coding problem involves a sender with K messages to be transmitted across a broadcast channel, and a set of receivers each of which demands a subset of the K messages while having prior knowledge of a different subset as side information. We consider the specific case of noisy index coding where the broadcast channel is Gaussian and every receiver demands all the messages from the source. Instances of this communication problem arise in wireless relay networks, sensor networks, and retransmissions in broadcast channels. We construct 'lattice index codes' for this channel by encoding the K messages individually using K modulo lattice constellations and transmitting their sum modulo a coarse lattice. We introduce a design metric called 'side information gain' that measures the advantage of a code in utilizing the side information at the receivers, and hence its goodness as an index code. Based on the Chinese remainder theorem, we then construct lattice index codes with large side information gains using lattices over the following principal ideal domains: rational integers, Gaussian integers, Eisenstein integers, and the Hurwitz quaternions. Among all lattice index codes constructed using any densest lattice of a given dimension, our codes achieve the maximum side information gain. Finally, using an example, we illustrate how the proposed lattice index codes can benefit Gaussian broadcast channels with more general message demands., Accepted for publication in the IEEE Transactions on Information Theory. Two-column format, 21 pages

A maximum-power-point-tracking DC-DC boost converter to harvest energy from sub- $\mu{\rm W}$ power sources is presented. For available input-power levels below 1 $\mu{\rm W}$ , voltage boosting is achieved by operating all circuits in the sub-threshold region, and by switching the DC-DC converter at tens of Hz, thereby reducing switching losses. The paper further explores the possibility of energizing the DC-DC inductor for an optimum duration, such that switching and resistive losses are minimized. The sub- $\mu{\rm W}$ energy harvesting circuit uses an area of 0.2 ${\rm mm}^{2}$ on a standard 180 nm CMOS process, and utilizes an auxiliary voltage source for start-up. The designed and fabricated system is more than 50% efficient when the available power is greater than 2 $\mu{\rm W}$ . The circuit can harvest energy whenever the available power is more than 0.3 $\mu{\rm W}$ . Efficiency at 0.3 $\mu{\rm W}$ is 25%, at 0.5 $\mu{\rm W}$ is 37% and at 1 $\mu{\rm W}$ is 48%. The complete IC consumes 50 nA for internal operations and the input voltage can be as low as 70 mV.

This paper proposes a novel reconfigurable microgrid architecture comprising photovoltaic, wind, microhydro, and fuel cell based renewable energy sources. Transient and extended power backup are provided with ultra-capacitor (UC) and battery storage, respectively. A distinguishing feature of this microgrid is that its various control layers can switch roles during emergency. As renewable energy sources with significantly different dynamic behavior and dissimilar generating capacities are involved, disruptive effects such as voltage dips and fluctuations, frequency variation, and harmonic distortion are likely. This is handled through centralized monitoring in conjunction with hierarchical control. The reliability and sustainability of the resulting complex microgrid architecture is ensured through the proposed reconfigurable control and power network of the microgrid, supported by a hybrid communication layer comprising CAN, RS-485, and MODBUS protocols. The proposed architecture is strengthened by an additional "advisory" layer comprising an advisory controller that supports long-term optimization of microgrid operation under normal conditions and governs interim role assignments to control layers during crisis. All these special features ensure continuity of power with sustained performance or gracefully degraded performance even under various kinds of faults and abnormal events. Design of various controllers, protection, and reconfigurability features with relevant analysis and experimental results are presented.

This letter proposes a high-speed and reconfigurable Discrete Hilbert Transform architecture design methodology targeting the real-time applications including Cyber-Physical systems, Internet of Things or Remote Health-Monitoring where the same chip-set needs to be used for various purposes under real-time scenario. By using this architecture we are able to get Discrete Hilbert Transform for any given M-point by re-using N-point Discrete Hilbert Transform as a kernel. Here N and M are multiple of 4 and N respectively. Subsequently we provide the architecture design details and compare the proposed architecture with the conventional state-of-the-art architecture. Thorough theoretical analysis and experimental comparison results show that the proposed design is twice as fast and reconfigurability is also achieved simultaneously