Yadav, Sandeep Kumar

Fast identification and classification of the faults in distribution network is a crucial task to ensure reliable power supply to the end user. This paper presents a protection scheme which makes use of Empirical Mode Decomposition of three phase current signals of a distribution network. The current signals measured at the substation bus over a moving window of one cycle are decomposed to obtain first level intrinsic mode function IMF1 and residue R1. A fault index which is nothing but the absolute mean of R1 is calculated for each phase and compared with a threshold to detect and categorize the type of fault. The proposed algorithm has been successfully tested on IEEE 13 bus system by varying the type of fault, fault incidence angle and fault location. The selectivity of the proposed scheme has been established by testing the algorithm with non faulty transients such as load switching and capacitor switching.

Instrumented versions of functional geriatric screening tests have been developed to improve clinical precision. Several different instrumented versions of the Sit-to-Stand (iSTS) test have been developed using a range of sensors such as accelerometers and cameras. An instrumented chair equipped with load cells and an ultrasound sensor was developed to detect phases of the STS (Sit to Stand). The chair was designed to be able to detect all the phases of the STS, including when the person was not in contact with the chair. Performance of the iSTS chair was compared between an RGB camera approach, and a data-fusion approach using the load-cell and ultrasound equipped chair. Ten adult subjects were tested performing the 5STS at two self-selected speeds. The accuracy of the load cell equipped chair was 70%, while the RGB camera achieved 76% accuracy. The ultrasound version of the chair and the fusion of the RGB and load cells technique both achieved significantly better accuracy at 86% and 89%, respectively. The new version of the instrumented chair obtained a high degree of accuracy in detecting the different phases of the STS and is suitable to detect STS phases without requiring additional sensors. Future work will test older subjects and aim to develop new parameters based on the phases of the STS as indicators of physical performance.

In this paper, an UWB antenna generated using Koch fractal geometry is presented. The application of Koch geometry at the edges of hexagonal geometry provides desired miniaturization and wideband phenomena. Moreover, to avoid any interference issues in UWB bands from narrowband systems such as WiMAX and WLAN, dual C-shaped notches are introduced in the monopole of the presented antenna design. The proposed antenna has compact dimensions of 31 mm × 27 mm, and exhibits good VSWR, stable radiation pattern and high gain outside notched band. Further, parametric study of notch parameters is also carried. The presented prototype is fabricated to validate the simulated results, and it shows good matching.

In this paper, a fractal ultrawideband multiple-input–multiple-output antenna is proposed and its characteristics are studied in free space as well as in the proximity of on-body wireless body area network scenario. The performance of the wideband antennas are affected strongly in the proximity of the human body. Koch fractal geometry is used at the outer edges of basic octagonal geometry in the design, which helps to achieve desired miniaturization, wideband and stable radiation pattern. The presented antenna has a compact size of 25 mm × 40 mm. In addition, the effect of body tissues on antenna characteristics is analyzed by a four layered (skin, fat, muscle and bone) human tissue model. The comparative analysis of S21 is performed at a various body parts position such as abdomen, near forehead and chest with different antenna orientations.

The notion of corona of two graphs was introduced by Frucht and Harary in 1970. In this paper, we generalize their definition of corona product of two graphs and introduce corona product of two signed graphs by utilizing the framework of marked graphs, which was introduced by Beineke and Harary in 1978. We study structural and spectral properties of corona product of signed graphs. Further, we define signed corona graphs by considering corona product of a fixed small signed graph with itself iteratively, and we call the small graph as the seed graph for the corresponding corona product graphs. Signed corona graphs can be employed as a signed network generative model for large growing signed networks. We study structural properties of corona graphs that include statistics of signed links, all types of signed triangles and degree distribution. Besides we analyze algebraic conflict of signed corona graphs generated by specially structured seed graphs. Finally, we show that a suitable choice of a seed graph can produce corona graphs which preserve properties of real signed networks.

In this study, a design approach to achieve multiresonance phenomena in ultra-wideband (UWB) bandwidth using fractal geometry is investigated. The introduction of Koch fractal geometry in monopole as well as in the ground plane of the antenna generates additional resonances, which helps to achieve entire UWB operational bandwidth. Therefore the bandwidth is increased up to 122%. Moreover, the fractal nature of the antenna also facilitates to obtain the stable radiation pattern. The compact dimension 31 mm × 28 mm of the antenna exhibits nearly omnidirectional radiation pattern, with good reflection coefficient over the entire UWB frequency range. The proposed prototype is fabricated and its measured results are in good agreement with the simulated one. The time-domain analysis of the antenna is performed and it is found that fidelity factor is better than 0.81, which shows good pulse preserving capability of the antenna.

The massive growth in mobile users and wireless technologies has resulted in increased data traffic and created demand for additional radio spectrum. This growing demand for radio spectrum has resulted in spectrum congestion and mandated the need for coexistence between radar and interfering communication emitters. To address the aforementioned issues, it is critical to review existing policies and evaluate new technologies that can utilize spectrum in an efficient and intelligent manner. Cognitive radio and cognitive radar are two promising technologies that exploit spectrum using dynamic spectrum access techniques. Additionally, introducing the bio-inspired concept ‘metacognition’ in a cognitive process has shown to increase the effectiveness and robustness of the cognitive radio and cognitive radar system. Metacognition is a high-order thinking agent that monitors and regulates the cognition process through a feedback and control process called the perception–action cycle. Extensive research has been done in the field of spectrum sensing in cognitive radio and spectral coexistence between radar and communication systems. This paper provides a detailed classification of spectrum sensing schemes and explains how dynamic spectrum access strategies share the spectrum between radar and communication systems. In addition to this, the fundamentals of cognitive radio, its architecture, spectrum management framework, and metacognition concept in radar are discussed. Furthermore, this paper presents various research issues, challenges, and future research directions associated with spectrum sensing in cognitive radar and dynamic spectrum access strategies in cognitive radar.

Frailty is of increasing concern due to the associated decrease in independence of elderly who suffer from the condition. An innovative system was designed in order to objectively quantify the level of frailty based on a series of remote tests, each of which used objects similar to those found in peoples' homes. A modified ball, known as the Grip-ball was used to evaluate maximal grip force and exhaustion during an entirely remote assessment. A smartphone equipped with a tri-axial accelerometer was used to estimate gait velocity and physical activity level. Finally, a bathroom scale was used to assess involuntary weight loss. The smart phone processes all of the data generated, before it is transferred to a remote server where the user, their entourage, and any medical professionals with authorization can access the data. This innovative system could enable the onset of frailty to be detected early, thus giving sufficient time for a targeted intervention program to be implemented, thereby increasing independence for elderly users. © 2013 IEEE.

We will discuss a small novel hexagonal shaped geometry for ultra wideband (UWB) monopole antenna with notch characteristics. The self-similar nature of this fractal like geometry provides higher effective antenna length and wide operating bandwidth because of the onset of multiple resonances. Notch characteristics are introduced using a rectangular slot in the ground plane, which enhances the reflection coefficient over the entire UWB frequency operating range for the proposed device. The optimized 19 mm × 15 mm dimensions, for the proposed antenna are the smallest among such geometries, exhibiting a large bandwidth from 3.1 GHz to 11.7 GHz with VSWR < 2 over the entire frequency range. The proposed antenna demonstrates nearly omnidirectional radiation pattern, proper impedance matching, and good return loss over the entire UWB frequency range.

Automatic modulation classification finds its application in many military and civil areas. It is an integral part of cognitive radio and software defined radio technologies. In this paper, LabVIEW based Field Programmable Gate Array (FPGA) implementation of modulation classification algorithm is proposed. Any modulation scheme among BPSK, QPSK, 8PSK, 8QAM, 16QAM and 4ASK is classified by alteration of oversampling factor and further error minimization between extracted constellation and ideal constellation of considered modulation schemes. Study results reveal that the developed method detects the above mentioned modulation schemes reliably above 12 dB SNR in Additive White Gaussian Noise (AWGN) channel. Comparative analysis of the proposed method with existing methods based on higher order statistics, mel-frequency ceptral coefficients and naive based modulation classification shows an overall improvement in classification accuracy.