Excellence in Research and Innovation for Humanity

International Science Index

Commenced in January 1999 Frequency: Monthly Edition: International Abstract Count: 39602

Electronics and Communication Engineering

Time-Frequency Feature Extraction Method Based on Micro-Doppler Signature of Ground Moving Targets
Since some discriminative features are required for ground moving targets classification, we propose a new feature extraction method based on micro-Doppler signature. Firstly, the time-frequency analysis of measured data indicates that the time-frequency spectrograms of the three kinds of ground moving targets, i.e., single walking person, two people walking and a moving wheeled vehicle, are discriminative. Then, a three-dimensional time-frequency feature vector is extracted from the time-frequency spectrograms to depict these differences. At last, a Support Vector Machine (SVM) classifier is trained with the proposed three-dimensional feature vector. The classification accuracy to categorize ground moving targets into the three kinds of the measured data is found to be over 96%, which demonstrates the good discriminative ability of the proposed micro-Doppler feature.
Change Detection Method Based on Scale-Invariant Feature Transformation Keypoints and Segmentation for Synthetic Aperture Radar Image
Synthetic aperture radar (SAR) image change detection has recently become a challenging problem owing to the existence of speckle noises. In this paper, an unsupervised distribution-free change detection for SAR image based on scale-invariant feature transform (SIFT) keypoints and segmentation is proposed. Firstly, the noise-robust SIFT keypoints which reveal the blob-like structures in an image are extracted in the log-ratio image to reduce the detection range. Then, different from the traditional change detection which directly obtains the change-detection map from the difference image, segmentation is made around the extracted keypoints in the two original multitemporal SAR images to obtain accurate changed region. At last, the change-detection map is generated by comparing the two segmentations. Experimental results on the real SAR image dataset demonstrate the effectiveness of the proposed method.
A Hop-By-Hop Transport Control Protocol for Navigation Satellite Network
Due to the constraints of navigation satellite and directional inter-satellite-link (ISL) antenna, the number of antennas that can be equipped on one navigation satellite is limited (e.g. only one ISL can be equipped). The ISLs of navigation satellite will be half-duplex and intermittent available, thus forming a time division multiplexing navigation satellite network. For network like this, the design of network protocol, especially the transport control protocol, is the key issue to provide efficient data transport service. This paper focuses on transport control protocol for time division multiplexing navigation satellite network. Since traditional end-to-end transport control protocol doesn’t perform well in such network, this paper proposes a hop-by-hop transport control protocol which has the following features: firstly, as the path is not available at all time, message will be stored in persistent storage of network nodes to wait for communication opportunity; secondly, the proposed hop-by-hop transport control protocol utilize automatic repeat request to achieve reliable transport and the acknowledgment and re-transmission will be performed between adjacent nodes rather than between source and destination nodes. Simulation results show that the data throughput of the proposed hop-by-hop transport control protocol is higher than traditional end-to-end transport control protocol. The traffic can also move more quickly and distribute more uniform.
Compact 3-D Co-Planar Waveguide Fed Dual-Port Ultrawideband-Multiple-Input and Multiple-Output Antenna with WLAN Band-Notched Characteristics
A miniaturized three dimensional co-planar waveguide (CPW) two-port MIMO antenna, exhibiting high isolation and WLAN band-notched characteristics is presented in this paper for ultrawideband (UWB) communication applications. The microstrip patch antenna operates as a single UWB antenna element. The proposed design is a cuboid-shaped structure having compact size of 35 x 27 x 45 mm³. Radiating as well as decoupling structure is placed around cuboidal polystyrene sheet. The radiators are 27 mm apart, placed Face-to-Face in vertical direction. Decoupling structure is placed on the side walls of polystyrene. The proposed antenna consists of an oval shaped radiating patch. A rectangular structure with fillet edges is placed on ground plan to enhance the bandwidth. The proposed antenna exhibits a good impedance match (S11 ≤ -10 dB) over frequency band of 2 GHz – 10.6 GHz. A circular slotted structure is employed as a decoupling structure on substrate, and it is placed on the side walls of polystyrene to enhance the isolation between antenna elements. Moreover, to achieve immunity from WLAN band distortion, a modified, inverted crescent shaped slotted structure is etched on radiating patches to achieve band-rejection characteristics at WLAN frequency band 4.8 GHz – 5.2 GHz. The suggested decoupling structure provides isolation better than 15 dB over the desired UWB spectrum. The envelope correlation coefficient (ECC) and gain for the MIMO antenna are analyzed as well. Finite Element Method (FEM) simulations are carried out in Ansys High Frequency Structural Simulator (HFSS) for the proposed design. The antenna is realized on a Rogers RT/duroid 5880 with thickness 1 mm, relative permittivity ɛr = 2.2. The proposed antenna achieves a stable omni-directional radiation patterns as well, while providing rejection at desired WLAN band. The S-parameters as well as MIMO parameters like ECC are analyzed and the results show conclusively that the design is suitable for portable MIMO-UWB applications.
A Sparse Representation Speech Denoising Method Based on Adapted Stopping Residue Error
A sparse representation speech denoising method based on adapted stopping residue error was proposed in this paper. Firstly, the cross-correlation between the clean speech spectrum and the noise spectrum was analyzed, and an estimation method was proposed. In the denoising method, an overcomplete dictionary of the clean speech power spectrum was learned with the K-Singular Value Decomposition (K-SVD) algorithm. In the sparse representation stage, the stopping residue error was adaptively achieved according to the estimated cross-correlation and the adjusted noise spectrum, and the orthogonal matching pursuit (OMP) approach was applied to reconstruct the clean speech spectrum from the noisy speech. Finally, the clean speech was re-synthesis via the inverse Fourier transform with the reconstructed speech spectrum and the noisy speech phase. The experiment results show that the proposed method outperforms the conventional methods in terms of subjective and objective measure.
Sidelobe Reduction in Cognitive Radio Systems Using Hybrid Technique
Orthogonal frequency division multiplexing (OFDM) is one the best candidate for dynamic spectrum access due to its flexibility of spectrum shaping. However the high sidelobes of the OFDM signal that results in high out-of-band radiation, introduces significant interference to the users operating in its vicinity. This problem becomes more critical in cognitive radio (CR) system that enables the un-licensed users to access the spectrum holes not used by the licensed users at that time. In this paper, we present a generalized OFDM framework that has a capability of describing any sidelobe suppression techniques, despite of whether one or a number of techniques are used. Based on that framework, we propose cancellation carrier (CC) technique in conjunction with the generalized sidelobe canceller (GSC) to reduce the out-of-band radiation in the region where the licensed users are operating. Simulation results shows that the proposed technique can reduce the out-of-band radiation better as compared with the existing techniques found in the literature.
A Compact Ultra-Wide Band Antenna with C-Shaped Slot for WLAN Notching
A patch antenna operating in the Ultra-Wide Band of frequency (3.1 GHz – 10.6 GHz) is designed with enhanced security from interference from other applications by incorporating the notching technique. Patch antennas in the Ultra-Wide Band are becoming widely famous due to their low power, light weight and high data rate capability. Micro strip patch antenna’s patch can be altered to increase its bandwidth and introduce UWB character in it. The designed antenna is a patch antenna consisting of a conductive sheet of metal mounted over a large sheet of metal called the ground plane with a substrate separating the two. Notched bands are public safety WLAN, WLAN and FSS. Different techniques used to implement the UWB antenna were individually implemented and there results were examined. V shaped patch was then chosen and modified to an arrow shaped patch to give the optimized results operating on the entire UWB region with considerable return loss. The frequency notch prevents the operation of the antenna at a particular range of frequency, hence minimizing interference from other systems. There are countless techniques for introducing the notch but we have used inverted C-shaped slots in the UWB patch to get the notch characteristics as output and also wavelength resonators to introduce notch in UWB band. The designed antenna is simulated in High Frequency Structural Simulator (HFSS) 13.0 by Ansoft.
Eigen Image Based Approach towards Estimation of Change in Illumination and Its Orientation
This paper presents a method for estimating camera pose in a digital video using interest points. The method works by first extracting key frames in a digital video based on motion vector calculation. Interest points in key frames are detected and pruning of interest points is done based on local and global histograms. Feature descriptors around each interest point are computed based on shape, texture and intensity levels. Euclidean distance is used as distance metric for comparing feature descriptors. From a set of candidate pairs of interest points, outliers are removed based on RANSAC. Epipolar geometry is then used to estimate camera position and orientation in these key frames. Interpolation is used to find camera pose in the whole video sequence from sparse set of camera pose points. The method has been tested on various types of videos like sports video, pedestrian video, digital broadcast video and street view image sequence. The method outperforms many other camera pose estimation methods as indicated by different performance indices.
Utilization of a Drone as a Unique Two-Way Field Probe to Quantify Radar Cross Section Measurement Uncertainty
RCS measurement accuracy is known when there is a method of quantifying the deviations in the electromagnetic waves that traverses the test volume or region where a target is measured. The process begins with the development of a shield capable of providing a characterizable RCS as it encapsulates the drone in flight. The position and pose data acquired from the drone must be synchronized with the RCS measurements of the field probe acquired from radar. The uncertainty of the drone's GPS and INS modules contributes to the overall accuracy of the drone's position and pose, therefore affecting the accuracy of the RCS measurement acquired within the test volume. This paper describes a unique methodology in which uncertainty of an RCS measurement conducted at a radar cross section range is quantified utilizing a drone as a unique two-way field probe.
Investigation of the Growth Kinetics of Phases in Ni–Sn System
Ni–Sn system finds applications in the microelectronics industry, especially with respect to flip–chip or direct chip, attach technology. Here the region of interest is under bump metallization (UBM), and solder bump (Sn) interface due to the formation of brittle intermetallic phases there. Understanding the growth of these phases at UBM/Sn interface is important, as in many cases it controls the electro–mechanical properties of the product. Cu and Ni are the commonly used UBM materials. Cu is used for good bonding because of fast reaction with solder and Ni often acts as a diffusion barrier layer due to its inherently slower reaction kinetics with Sn–based solders. Investigation on the growth kinetics of phases in Ni–Sn system is reported in this study. Just for simplicity, Sn being major solder constituent is chosen. Ni–Sn electroplated diffusion couples are prepared by electroplating pure Sn on Ni substrate. Bulk diffusion couples prepared by the conventional method are also studied along with Ni–Sn electroplated diffusion couples. Diffusion couples are annealed for 25–1000 h at 50–215°C to study the phase evolutions and growth kinetics of various phases. The interdiffusion zone was analysed using field emission gun equipped scanning electron microscope (FE–SEM) for imaging. Indexing of selected area diffraction (SAD) patterns obtained from transmission electron microscope (TEM) and composition measurements done in electron probe micro−analyser (FE–EPMA) confirms the presence of various product phases grown across the interdiffusion zone. Time-dependent experiments indicate diffusion controlled growth of the product phase. The estimated activation energy in the temperature range 125–215°C for parabolic growth constants (and hence integrated interdiffusion coefficients) of the Ni₃Sn₄ phase shed light on the growth mechanism of the phase; whether its grain boundary controlled or lattice controlled diffusion. The location of the Kirkendall marker plane indicates that the Ni₃Sn₄ phase grows mainly by diffusion of Sn in the binary Ni–Sn system.
Spectral Domain Fast Multipole Method for Solving Integral Equations of One and Two Dimensional Wave Scattering
In this paper, a spectral domain implementation of the fast multipole method is presented. It is shown that the aggregation, translation, and disaggregation stages of the fast multipole method (FMM) can be performed using the spectral domain (SD) analysis. The spectral domain fast multipole method (SD-FMM) has the advantage of eliminating the near field/far field classification used in conventional FMM formulation. The study focuses on the application of SD-FMM to one-dimensional (1D) and two-dimensional (2D) electric field integral equation (EFIE). The case of perfectly conducting strip, circular and square cylinders are numerically analyzed and compared with the results from the standard method of moments (MoM).
Clustering Based Level Set Evaluation for Low Contrast Images
The important object of images segmentation is to extract objects with respect to some input features. One of the important methods for image segmentation is Level set method. Generally medical images and synthetic images with low contrast of pixel profile, for such images difficult to locate interested features in images. In conventional level set function, develops irregularity during its process of evaluation of contour of objects, this destroy the stability of evolution process. For this problem a remedy is proposed, a new hybrid algorithm is Clustering Level Set Evolution. Kernel fuzzy particles swarm optimization clustering with the Distance Regularized Level Set (DRLS) and Selective Binary, and Gaussian Filtering Regularized Level Set (SBGFRLS) methods are used. The ability of identifying different regions becomes easy with improved speed. Efficiency of the modified method can be evaluated by comparing with the previous method for similar specifications. Comparison can be carried out by considering medical and synthetic images.
Speed-Up Data Transmission by Using Bluetooth Module on Gas Sensor Node of Arduino Board
Internet of Things (IoT) applications are widely serviced and spread worldwide. Local wireless data transmission technique must be developed to speed up with some technique. Bluetooth wireless data communication is wireless technique is technique made by Special Inter Group(SIG) using the frequency range 2.4 GHz, and it is exploiting Frequency Hopping to avoid collision with different device. To implement experiment, equipment for experiment transmitting measured data is made by using Arduino as Open source hardware, Gas sensor, and Bluetooth Module and algorithm controlling transmission speed is demonstrated. Experiment controlling transmission speed also is progressed by developing Android Application receiving measured data, and controlling this speed is available at the experiment result. it is important that in the future, improvement for communication algorithm be needed because few error occurs when data is transferred or received.
Optimal Tuning of LQR Controller Using a Particle Swarm Optimization for Two Rotors Aerodynamical System
This paper presents an optimal state feedback controller based on Linear Quadratic Regulator (LQR) for a two rotor aero-dynamical system (TRAS). TRAS is a highly nonlinear multi-input multi-output (MIMO) system with two degrees of freedom and cross coupling. There are two parameters that define the behavior of LQR controller: state weighting matrix and control weighting matrix. The two parameters influence the performance of LQR. Particle Swarm Optimization (PSO) is proposed to optimally tune weighting matrices of LQR The major concern of using LQR controller is to stabilize the TRAS by making the beam move quickly and accurately for tracking a trajectory or to reach a desired altitude. The simulation results were carried out in MATLAB/SIMULINK. The system is decoupled into two single-input single-output (SISO) systems. Comparing the performance of the optimized proportional, integral and derivative (PID) controller provided by INTECO, results depict that LQR controller gives a better performance in terms of both transient and steady state responses when PSO is performed.
A 1T1R Nonvolatile Memory with Al/TiO₂/Au and Sol-Gel Processed Barium Zirconate Nickelate Gate in Pentacene Thin Film Transistor
To avoid the cross-talk issue of only resistive random access memory (RRAM) cell, one transistor and one resistor (1T1R) architecture with a TiO₂-based RRAM cell connected with solution barium zirconate nickelate (BZN) organic thin film transistor (OTFT) device is successfully demonstrated. The OTFT were fabricated on a glass substrate. Aluminum (Al) as the gate electrode was deposited via a radio-frequency (RF) magnetron sputtering system. The barium acetate, zirconium n-propoxide, and nickel II acetylacetone were synthesized by using the sol-gel method. After the BZN solution was completely prepared using the sol-gel process, it was spin-coated onto the Al/glass substrate as the gate dielectric. The BZN layer was baked at 100 °C for 10 minutes under ambient air conditions. The pentacene thin film was thermally evaporated on the BZN layer at a deposition rate of 0.08 to 0.15 nm/s. Finally, gold (Au) electrode was deposited using an RF magnetron sputtering system and defined through shadow masks as both the source and drain. The channel length and width of the transistors were 150 and 1500 μm, respectively. As for the manufacture of 1T1R configuration, the RRAM device was fabricated directly on drain electrodes of TFT device. A simple metal/insulator/metal structure, which consisting of Al/TiO₂/Au structures, was fabricated. First, Au was deposited to be a bottom electrode of RRAM device by RF magnetron sputtering system. Then, the TiO₂ layer was deposited on Au electrode by sputtering. Finally, Al was deposited as the top electrode. The electrical performance of the BZN OTFT was studied, showing superior transfer characteristics with the low threshold voltage of −1.1 V, good saturation mobility of 5 cm²/V s, and low subthreshold swing of 400 mV/decade. The integration of the BZN OTFT and TiO₂ RRAM devices was finally completed to form 1T1R configuration with low power consumption of 1.3 μW, the low operation current of 0.5 μA, and reliable data retention. Based on the I-V characteristics, the different polarities of bipolar switching are found to be determined by the compliance current with the different distribution of the internal oxygen vacancies used in the RRAM and 1T1R devices. Also, this phenomenon can be well explained by the proposed mechanism model. It is promising to make the 1T1R possible for practical applications of low-power active matrix flat-panel displays.
A Context-Sensitive Algorithm for Media Similarity Search
This paper proposes a context-sensitive media similarity search algorithm. One of the central problems regarding media search is the semantic gap between the low-level features computed automatically from media data and the human interpretation of them. This is because the notion of similarity is usually based on high-level abstraction, but the low-level features do not sometimes reflect the human perception. Many media search algorithms have used the Minkowski metric to measure the similarity between image pairs. However, those functions cannot adequately capture the aspects of the characteristics of the human visual system as well as the nonlinear relationships in contextual information given by images in a collection. Our new search algorithm tackles this problem by employing a new similarity measure and a ranking strategy that reflect the nonlinearity of human perception and contextual information in a dataset. Similarity search in an image database based on this contextual information shows encouraging experimental results.
Discrimination of Modes of Double and Single-Negative Grounded Slabs
In this paper, we investigate theoretically the waves propagation in a lossless double-negative grounded slab (DNG). This study is released by the Transverse Resonance Method (TRM). The proper or improper nature of real and complex modes is observed. They are highly dependent on metamaterial parameters being ɛr-negative, µr-negative or both. Numerical results provided that only the proper complex modes (i.e., leaky modes) exist in double-negative grounded slab and only the improper complex modes exist in single-negative grounded slab.
On-Chip Aging Sensor Circuit Based on Phase Locked Loop Circuit
In sub micrometer technology the aging phenomenon starting to have a significant impact on reliability of integrated circuits by bringing performance degradation. That is why it is important to have a capability to evaluate the aging effects accurately. In this paper proposed an accurate aging measurement approach based on phase-locked loop (PLL) and voltage-controlled oscillator (VCO) circuit. The proposed architecture is rejecting the circuit self-aging effect from the characteristics of PLL, which is generating the frequency without any aging phenomena affects. The aging monitor is implemented in low power 32 nm CMOS technology, and occupies pretty small area. Aging simulations results are showing that the proposed aging measurement circuit improves accuracy by about 2.8% at high temperature and 19.6% at high voltage.
Metal-Oxide-Semiconductor-Only Process Corner Monitoring Circuit
A new process corner monitoring circuit (PCMC) is presented in this work. The circuit generates a signal, the logical value of which depends on the process corner only. The signal can be used in both digital and analog circuits for testing and compensation of process variations (PV). The proposed circuit uses only metal-oxide-semiconductor (MOS) transistors, which allows increasing its detection accuracy, decrease power consumption and area. Due to its simplicity, the proposed circuit can be easily modified to monitor parametrical variations of only n-type and p-type MOS (NMOS and PMOS respectively) transistors, resistors, as well as their combinations. Post-layout simulation results prove correct functionality of the proposed circuit, i.e. ability to monitor the process corner (equivalently die-to-die variations) even in the presence of within-die variations.
Object Oriented Fault Tree Analysis Methodology
Traditional safety, risk and reliability analysis approaches are problem-oriented, which make it great workload when analyzing complicated and huge system, besides, too much repetitive work would to do if the analyzed system composed by many similar components. It is pressing need an object and function oriented approach to maintain high consistency with problem domain. A new approach is proposed to overcome these shortcomings of traditional approaches, the concepts: class, abstract, inheritance, polymorphism and encapsulation are introduced into FTA and establish the professional class library that the abstractions of physical objects in real word, four areas relevant information also be proposed as the establish help guide. The interaction between classes is completed by the inside or external methods that mapping the attributes to base events through fully search the knowledge base, which forms good encapsulation. The object oriented fault tree analysis system that analyze and evaluate the system safety and reliability according to the original appearance of the problem is set up, where could mapped directly from the class and object to the problem domain of the fault tree analysis. All the system failure situations can be analyzed through this bottom-up fault tree construction approach. Under this approach architecture, FTA approach is developed, which avoids the human influence of the analyst on analysis results. It reveals the inherent safety problems of analyzed system itself and provides a new way of thinking and development for safety analysis. So that object oriented technology in the field of safety applications and development, safety theory is conducive to innovation.
High Efficiency Perovskite Solar Cells Fabricated under Ambient Conditions with Mesoporous TiO₂ / In₂O₃ Scaffold
Mesoscopic perovskite solar cells (mp-PSCs) with mesoporous bilayer were fabricated under ambient conditions. The bilayer was formed by capping the mesoporous TiO₂ layer with a layer of In₂O₃. CH₃NH₃I₃₋ₓClₓ mixed halide perovskite was prepared through the one-step method and was used as the light absorber. The mp-PSCs with the composite TiO₂/In₂O₃ mesoporous layer exhibited optimized electrical parameters, compared with the PSCs that employed only a TiO₂ mesoporous layer, with a current density of 23.86 mA/cm², open circuit voltage of 0.863 V, fill factor of 0.6 and a power conversion efficiency of 11.2%. These results indicate that the formation of a proper semiconductor capping layer over the basic TiO₂ mesoporous layer can facilitate the electron transfer, suppress the recombination and subsequently lead to higher charge collection efficiency.
Statistical Modeling of Mobile Fading Channels Based on Triply Stochastic Filtered Marked Poisson Point Processes
Understanding the statistics of non-isotropic scattering multipath channels that fade randomly with respect to time, frequency, and space in a mobile environment is very crucial for the accurate detection of received signals in wireless and cellular communication systems. In this paper, we derive stochastic models for the probability density function (pdf) of the shift in the carrier frequency caused by the Doppler effect on the received illuminating signal in the presence of a dominant line of sight. Our derivation is based on a generalized Clarke’s and a two-wave partially developed scattering models, where the statistical distribution of the frequency shift is shown to be consistent with the power spectral density of the Doppler shifted signal.
Peak Data Rate Enhancement Using Switched Micro-Macro Diversity in Cellular Multiple-Input-Multiple-Output Systems
With the exponential growth of cellular users, a new generation of cellular networks is needed to enhance the required peak data rates. The co-channel interference between neighboring base stations inhibits peak data rate increase. To overcome this interference, multi-cell cooperation known as coordinated multipoint transmission is proposed. Such a solution makes use of multiple-input-multiple-output (MIMO) systems under two different structures: Micro- and macro-diversity. In this paper, we study the capacity and bit error rate in cellular networks using MIMO technology. We analyse both micro- and macro-diversity schemes and develop a hybrid model that switches between macro- and micro-diversity in the case of hard handoff based on a cut-off range of signal-to-noise ratio values. We conclude that our proposed hybrid switched micro-macro MIMO system outperforms classical MIMO systems at the cost of increased hardware and software complexity.
A Near-Optimal Domain Independent Approach for Detecting Approximate Duplicates
We propose a domain-independent merging-cluster filter approach complemented with a set of algorithms for identifying approximate duplicate entities efficiently and accurately within a single and across multiple data sources. The near-optimal merging-cluster filter (MCF) approach is based on the Monge-Elkan well-tuned algorithm and extended with an affine variant of the Smith-Waterman similarity measure. Then we present constant, variable, and function threshold algorithms that work conceptually in a divide-merge filtering fashion for detecting near duplicates as hierarchical clusters along with their corresponding representatives. The algorithms take recursive refinement approaches in the spirit of filtering, merging, and updating, cluster representatives to detect approximate duplicates at each level of the cluster tree. Experiments show a high effectiveness and accuracy of the MCF approach in detecting approximate duplicates by outperforming the seminal Monge-Elkan’s algorithm on several real-world benchmarks and generated datasets.
Clustering Based Level Set Evaluation for Low Contrast Images
The important object of images segmentation is to extract objects with respect to some input features. One of the important methods for image segmentation is Level set method. Generally medical images and synthetic images with low contrast of pixel profile, for such images difficult to locate interested features in images. In conventional level set function, develops irregularity during its process of evaluation of contour of objects, this destroy the stability of evolution process. For this problem a remedy is proposed, a new hybrid algorithm is Clustering Level Set Evolution. Kernel fuzzy part icles swarm optimization clustering with the Distance Regularized Level Set (DRLS) and Selective Binary and Gaussian Filtering Regularized Level Set (SBGFRLS) method are used. The ability of identifying different regions becomes easy with improved speed. Efficiency of modified method can be evaluated by comparing with the previous method for similar specifications. The comparison can be carried out by considering medical and synthetic images.
Tunable C and L Bands Demultiplexer Based on Photonic Crystal Ring Resonator
In this paper, we propose a demultiplexer based on photonic crystal ring resonator (PCRR) that can separate two wavelengths in C and L bands. We used a circular ring resonator with a reduced period a = 500 nm to separate two different wavelengths, those wavelength defined by DWDM ITU grid. The structure is built of a square lattice of rods with the refractive index n = 3.6 embedded in air. The value of the crosstalk between output channels and the size of the proposed demultiplexer are about −36 dB and 107.038 µm2, respectively with higher efficient transmission equals to 96%. The Plane Wave Expansion (PWE) method and 2D Finite Difference Time Domain (FDTD) method are used to calculate the Photonic Band Gap (PBG) range and outputs spectrums.
Insight2OSC: Using Electroencephalography (EEG) Rhythms from the Emotiv Insight for Musical Composition via Open Sound Control (OSC)
The artistic usage of Brain-computer interfaces (BCI), initially intended for medical purposes, has increased in the past few years as they become more affordable and available for the general population. One interesting question that arises from this practice is whether it is possible to compose or perform music by using only the brain as a musical instrument. In order to approach this question, we propose a BCI for musical composition, based on the representation of some mental states as the musician thinks about sounds. We developed software, called Insight2OSC, that allows the usage of the Emotiv Insight device as a musical instrument, by sending the EEG data to audio processing software such as MaxMSP through the OSC protocol. We provide two compositional applications bundled with the software, which we call Mapping your Mental State and Thinking On. The signals produced by the brain have different frequencies (or rhythms) depending on the level of activity, and they are classified as one of the following waves: delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta (13-30 Hz), gamma (30-50 Hz). These rhythms have been found to be related to some recognizable mental states. For example, the delta rhythm is predominant in a deep sleep, while beta and gamma rhythms have higher amplitudes when the person is awake and very concentrated. Our first application (Mapping your Mental State) produces different sounds representing the mental state of the person: focused, active, relaxed or in a state similar to a deep sleep by the selection of the dominants rhythms provided by the EEG device. The second application relies on the physiology of the brain, which is divided into several lobes: frontal, temporal, parietal and occipital. The frontal lobe is related to abstract thinking and high-level functions, the parietal lobe conveys the stimulus of the body senses, the occipital lobe contains the primary visual cortex and processes visual stimulus, the temporal lobe processes auditory information and it is important for memory tasks. In consequence, our second application (Thinking On) processes the audio output depending on the users’ brain activity as it activates a specific area of the brain that can be measured using the Insight device.
Analyzing the Critical Factors Influencing Employees' Tacit and Explicit Knowledge Sharing Intentions for Sustainable Competitive Advantage: A Systematic Review and a Conceptual Framework
Due to the importance of knowledge in today’s competitive world, an understanding of how to enhance employee knowledge sharing has become critical. This study discerning employees’ knowledge sharing intentions according to the type of knowledge to be shared, whether tacit or explicit. This study provides a critical and systematic review of the current literature on knowledge sharing, with a particular focus on the most critical factors influencing employees’ tacit and explicit knowledge sharing intentions. The extant literature was identified through four electronic databases, from 2006 to 2016. The findings of this review reveal that most of the previous studies only focus on individual and social factors as the antecedents of knowledge sharing intention. Therefore, those previous studies did not consider some other potential factors, like organizational and technological factors that may hinder the progress of knowledge sharing processes. Based on the findings of the critical review, a conceptual framework is proposed, which presents the antecedents of employees’ tacit and explicit knowledge sharing intentions and its impact on innovation and sustainable competitive advantage.
Experimental Networks Synchronization of Chua’s Circuit in Different Topologies
In this work, we deal with experimental network synchronization of chaotic nodes with different topologies. Our approach is based on complex system theory, and we use a master-slave configuration to couple the nodes in the networks. In particular, we design and implement electronically complex dynamical networks composed by nine coupled chaotic Chua’s circuits with topologies: in nearest-neighbor, small-world, open ring, star, and global. Also, network synchronization is evaluated according to a particular coupling strength for each topology. This study is important by the possible applications to private transmission of information in a chaotic communication network of multiple users.
An Addressing Scheme for an Internet of Things (IoT) Network
The goal of this paper is to propose a new addressing scheme that allows for assigning a unique IPv6 address to each node in the Internet of Things (IoT) network. This scheme guarantees uniqueness by extracting the clock skew of each communication device and converting it into an IPv6 address. Simulation analysis confirms that the proposed scheme provide reductions in terms of energy consumption, communication overhead and response time as compared to four studied addressing schemes Strong DAD, LEADS, SIPA and CLOSA.