Excellence in Research and Innovation for Humanity

International Science Index

Commenced in January 1999 Frequency: Monthly Edition: International Abstract Count: 48522

Electronics and Communication Engineering

898
83795
Barrier Characteristics of Molecular Semiconductor-Based Organic/Inorganic Au/C₄₂H₂₈/n-InP Hybrid Junctions
Authors:
Abstract:
Thin film of polycyclic aromatic hydrocarbon rubrene, C₄₂H₂₈ (5,6,11,12-tetraphenyltetracene), has been surfaced on Moderately Doped (MD) n-InP substrate as an interfacial layer by means of spin coating technique for the electronic modification of Au/MD n-InP structure. Ex situ annealing has been carried out at 150 °C for three minutes under a brisk flow of nitrogen for the better adhesion of the deposited film with the substrate surface. Room temperature electrical characterization has been performed on the C₄₂H₂₈/MD n-InP hybrid junctions by current-voltage (I-V) and capacitance-voltage (C-V) measurement in the dark. It has been seen that the C₄₂H₂₈/MD n-InP structure demonstrated extraordinary rectifying behavior. An effective barrier height (BH) as high as 0.743 eV, along with an ideality factor very close to unity (n=1.203), has been achieved for C₄₂H₂₈/n-InP organic/inorganic device. A thin C₄₂H₂₈ interfacial layer between Au and MD n-InP also reduce the reverse leakage current by almost four orders of magnitude and enhance the BH about 0.278 eV. This good performance of the device is ascribed to the passivation effect of organic interfacial layer between Au and n-InP. By using C-V measurement, in addition, the value of BH of the C₄₂H₂₈/n-InP organic/inorganic hybrid junctions have been obtained as 0.796 eV. It has been seen that both of the BH value (0.743 and 0.796 eV) for the organic/inorganic hybrid junction obtained I-V and C-V measurement, respectively are significantly larger than that of the conventional Au/n-InP structure (0.465 and 0.503 eV). It was also seen that the device had good sensitivity to the light under 100 mW/cm² illumination conditions. The obtained results indicated that modification of the interfacial potential barrier for Metal/n-InP junctions might be attained using polycyclic aromatic hydrocarbon thin interlayer C₄₂H₂₈.
Digital Article Identifier (DAI):
897
83695
An Implementation of Configurable UART-To-Ethernet Converter
Abstract:
This paper introduces an implementation of a configurable UART-to-Ethernet converter using an ARM-based 32-bit microcontroller as well as a dedicated program running on a PC for configuring the operating parameters of the converter. The program was written in Python. Various parameters related to the operation of the converter are configurable through the Ethernet interface of the converter. The converter supports 3 representative asynchronous serial communication protocols, RS-232, RS-422, and RS-485 and supports 3 network modes, TCP/IP server, TCP/IP client, and UDP client. The TCP/IP and UDP protocols were implemented on the microcontroller using an open source TCP/IP protocol stack called lwIP (A lightweight TCP/IP) and a free real-time operating system for embedded systems called FreeRTOS. Due to the use of FreeRTOS, the firmware of the converter was implemented as a multi-thread application and thus becomes more modular. The converter can provide a seamless bridge between a serial port and an Ethernet port, thereby allowing existing legacy hardware with no Ethernet connectivity to communicate using the Ethernet protocol.
Digital Article Identifier (DAI):
896
83499
A Framework for the Design of Green Giga Passive Optical Fiber Access Network in Kuwait
Abstract:
In this work, a practical study on a commissioned GPON fiber to the home access network in Kuwait is presented. The work covers the framework of the conceptual design of the deployed PONs access network, optical fiber cable network distribution, technologies adopted, and protocols. The work also describes methodologies applied by system designers for the proper selection of the type of ONTs and OLTs transceivers with respect to the distance, operating wavelengths, splitting ratios. The results have demonstrated and justified the limitation of transmission distance of a PON link in FTTx to not exceed 20km. OTDR test has been carried for this project to confirm compliance with ITU specifications regarding the total length of the deployed optical cable, total loss in dB, and loss per km in dB/km with respect to the operating wavelengths. OTDR test results with traces for segments of implemented fiber network will be provided and discussed.
Digital Article Identifier (DAI):
895
83335
A Methodology for Reliable Detection of ‎Anomalous Behavior of Wireless Sensors
Abstract:
Security in wireless devices and IoT (Internet of Things) have become critical with an increase in the number of devices and their applications in security-critical applications, namely, smart grids, intelligent transportation systems, monitoring of natural borders, to name a few. Remote monitoring of all the sensors and wireless devices is not feasible because of the sheer numbers of them in use. This makes autonomous monitoring and detection of anomalous behavior extremely important in maintaining network and device security. An anomaly is any deviation from the expected behavior of the device and the anomalous behavior could be due to gradual degradation of the device, change in the execution environment or due to the presence of an external agent such as malware. An anomaly of any kind may lead to loss of confidential data, data theft or loss of connectivity. Hence, the need for a reliable or dependable IoT network. This paper deals with the detection of anomalous behavior in smartphones. Different applications in smartphones result in different power consumption patterns. The fact that every application has been coded to perform different tasks leads to the claim that every action onboard (whether software or hardware) will consequently have a trace in the power consumption of the smartphone. When the same sequence of steps are repeated on a smartphone, it is observed that the power consumption patterns hold some degree of similarity. An anomalous behavior on the smartphone would result in a reduction in the similarity of the power consumption pattern. This change in similarity can be used to detect the presence of anomalous behavior on smartphones. The test bench used for the experiments has a Monsoon Power Meter, which supplies power to the smartphone, and an external laptop collects the power samples from the meter. In this paper, we have developed a methodology for reliable detection of anomalous behavior from the power signatures of the device. The methodology comprises steps as follows. In Step 1, the power consumed by different applications of the smartphone is recorded in a trusted environment. These signals form the Ground truths for the detection of anomalous behavior. In Step 2, the cross-correlation coefficients of the signals measured in step 1 are calculated and these coefficients are used for establishing thresholds. In Step 3, the smartphone exposed to the external environment is tested for the presence of anomalous behavior. The power consumed by an application on the smartphone is measured and the cross-correlation coefficients of the measured signal and the ground truths established in step 1 for that particular app, are calculated. In Step 4, the coefficients calculated in step 3 are compared to the thresholds from step 2 and based on the results it is determined if the smartphone has an anomalous behavior. Finally, to validate the methodology we will follow the following steps: (i) we will consider different types of foreground applications; (ii) we will emulate hardware failure by changing the number of cores in the processor; and (iii) change in the execution environment.
Digital Article Identifier (DAI):
894
82993
The Security Trade-Offs in Resource Constrained Nodes for IoT Application
Abstract:
The concept of the Internet of Things (IoT) has received much attention over the last five years. It is predicted that the IoT will influence every aspect of our lifestyles in the near future. The Wireless Sensor Network (WSN) is one of the key enablers of the operation of IoTs, allowing data to be collected from the surrounding environment. A sensor network consists of a large number of battery-driven sensor nodes which have a limited capability to sense, compute and communicate with each other in a specific location for a specific purpose. However, due to limited resources, the nature of deployment, and unattended operation, WSNs are vulnerable to several types of attack. Security is paramount for reliable and safe communication between IoT embedded devices. It has become essential to many IoT applications, but it does, however, come at a cost to resources. Nodes are usually equipped with small batteries, which makes energy conservation crucial to WSNs. Therefore, traditional security services such as encryption, authentication and key exchange mechanisms, which incur a high overhead on sensor node resources, cannot be applied directly in WSNs. Nevertheless, security cost in terms of energy consumption has not been studied sufficiently. Numerous researches have used a security specification of 802.15.4 for IoT applications, but the energy cost of each security level and the impact on Quality of Services (QoS) parameters remain unknown. This research focuses on the cost of security at the IoT Media Access Control (MAC) layer. It begins by studying the energy consumption of IEEE 802.15.4 security levels, continues with an evaluation of the impact of security on data latency and throughput, and then presents the impact of transmission power on security overhead, and finally, shows the effects of security on memory footprint. The Cooja emulator, which comes with Contiki Operating System (OS), and Tmote Sky nodes are used to obtain the results in this paper. The employed MAC protocol affects the cost measurement, hence, for accuracy, the effects of MAC and Radio Duty Cycle protocols on the security cost have been excluded. The results show that security overhead in terms of energy consumption with a payload of 24 bytes fluctuates between 31.5% at minimum level over non-secure packets and 60.4% at the top security level of 802.15.4 security specification. Also, it shows that security cost has less impact at longer frame lengths, and more with smaller frame size. In addition, the results depict a significant impact on data latency and throughput. Overall, maximum authentication length decreases throughput by almost 53%, and encryption and authentication together by almost 62%. Finally, the results show how security cost is affected by transmission power. It demonstrates that Microcontroller Unit (MCU) overhead become more visible, in comparison to the radio cost, when the transmission power is reduced and affects overall energy consumption. The overall security cost will be higher with low transmission power. The results of this research are aimed to benefit network designers and researchers in terms of security cost, and allow them to choose the level which suits their application requirements.
Digital Article Identifier (DAI):
893
82843
Electromagnetic Modeling of a MESFET Transistor Using the Moments Method Combined with Generalised Equivalent Circuit Method
Abstract:
The communications' and radar systems' demands give rise to new developments in the domain of active integrated antennas (AIA) and arrays. The main advantages of AIA arrays are the simplicity of fabrication, low cost of manufacturing, and the combination between free space power and the scanner without a phase shifter. The integrated active antenna modeling is the coupling between the electromagnetic model and the transport model that will be affected in the high frequencies. Global modeling of active circuits is important for simulating EM coupling, interaction between active devices and the EM waves, and the effects of EM radiation on active and passive components. The current review focuses on the modeling of the active element which is a MESFET transistor immersed in a rectangular waveguide. The proposed EM analysis is based on the Method of Moments combined with the Generalised Equivalent Circuit method (MOM-GEC). The Method of Moments which is the most common and powerful software as numerical techniques have been used in resolving the electromagnetic problems. In the class of numerical techniques, MOM is the dominant technique in solving of Maxwell and Transport’s integral equations for an active integrated antenna. In this situation, the equivalent circuit is introduced to the development of an integral method formulation based on the transposition of field problems in a Generalised equivalent circuit that is simpler to treat. The method of Generalised Equivalent Circuit (MGEC) was suggested in order to represent integral equations circuits that describe the unknown electromagnetic boundary conditions. The equivalent circuit presents a true electric image of the studied structures for describing the discontinuity and its environment. The aim of our developed method is to investigate the antenna parameters such as the input impedance and the current density distribution and the electric field distribution. In this work, we propose a global EM modeling of the MESFET AsGa transistor using an integral method. We will begin by describing the modeling structure that allows defining an equivalent EM scheme translating the electromagnetic equations considered. Secondly, the projection of these equations on common-type test functions leads to a linear matrix equation where the unknown variable represents the amplitudes of the current density. Solving this equation resulted in providing the input impedance, the distribution of the current density and the electric field distribution. From electromagnetic calculations, we were able to present the convergence of input impedance for different test function number as a function of the guide mode numbers. This paper presents a pilot study to find the answer to map out the variation of the existing current evaluated by the MOM-GEC. The essential improvement of our method is reducing computing time and memory requirements in order to provide a sufficient global model of the MESFET transistor.
Digital Article Identifier (DAI):
892
82831
Tunable Graphene Metasurface Modeling Using the Method of Moment Combined with Generalised Equivalent Circuit
Abstract:
Metamaterials crossover classic physical boundaries and gives rise to new phenomena and applications in the domain of beam steering and shaping. Where electromagnetic near and far field manipulations were achieved in an accurate manner. In this sense, 3D imaging is one of the beneficiaries and in particular Denis Gabor’s invention: holography. But, the major difficulty here is the lack of a suitable recording medium. So some enhancements were essential, where the 2D version of bulk metamaterials have been introduced the so-called metasurface. This new class of interfaces simplifies the problem of recording medium with the capability of tuning the phase, amplitude, and polarization at a given frequency. In order to achieve an intelligible wavefront control, the electromagnetic properties of the metasurface should be optimized by means of solving Maxwell’s equations. In this context, integral methods are emerging as an important method to study electromagnetic from microwave to optical frequencies. The method of moment presents an accurate solution to reduce the problem of dimensions by writing its boundary conditions in the form of integral equations. But solving this kind of equations tends to be more complicated and time-consuming as the structural complexity increases. Here, the use of equivalent circuit’s method exhibits the most scalable experience to develop an integral method formulation. In fact, for allaying the resolution of Maxwell’s equations, the method of Generalised Equivalent Circuit was proposed to convey the resolution from the domain of integral equations to the domain of equivalent circuits. In point of fact, this technique consists in creating an electric image of the studied structure using discontinuity plan paradigm and taken into account its environment. So that, the electromagnetic state of the discontinuity plan is described by generalised test functions which are modelled by virtual sources not storing energy. The environmental effects are included by the use of an impedance or admittance operator. Here, we propose a tunable metasurface composed of graphene-based elements which combine the advantages of reflectarrays concept and graphene as a pillar constituent element at Terahertz frequencies. The metasurface’s building block consists of a thin gold film, a dielectric spacer SiO₂ and graphene patch antenna. Our electromagnetic analysis is based on the method of moment combined with generalised equivalent circuit (MoM-GEC). We begin by restricting our attention to study the effects of varying graphene’s chemical potential on the unit cell input impedance. So, it was found that the variation of complex conductivity of graphene allows controlling the phase and amplitude of the reflection coefficient at each element of the array. From the results obtained here, we were able to determine that the phase modulation is realized by adjusting graphene’s complex conductivity. This modulation is a viable solution compared to tunning the phase by varying the antenna length because it offers a full 2π reflection phase control.
Digital Article Identifier (DAI):
891
82766
Development and Range Testing of a LoRaWAN System in an Urban Environment
Abstract:
Wireless Sensor Networks are finding application in many areas, but their wider use is being held back by the non-ideal performance of conventional short-range radio protocols such as Zigbee or Bluetooth. These are limited to a reliable range of a few 10s of metres, but most environments require operation over a larger scale than this. LoRa modulation, a proprietary variant of Chirp Spread Spectrum (CSS) modulation, owned by Semtech Incorporated, offers a solution. Operating in the physical layer, it provides features such as an adaptive data rate and high range performance. Being at the lowest layer in a network implementation, it can act as the base layer for protocols such as the LoRaWAN MAC layer amongst others. In this work, we build a LoRaWan infrastructure and test the range performance of a bespoke nodes design in an urban environment around the university. Range test is carried out in a typical urban environment and ranges of in excess of 8 km are achievable. It is apparent that the topology over such distances is important and a line of sight is required for good communication. With careful selection of the topology, longer ranges are possible. We investigate the effect of the altitude of the node on range and conclude that although topology is important for extreme performance, over shorter ranges of 2km, reliable communication is possible under most circumstances. The base station software architecture developed allows simple access for multiple users, and the bespoke node design, based on an ARM M0+ processor core, and a low-cost HopeRF RFM95W transceiver allows an easy to use, low cost, low power solution for low data rate applications. We will present the design and power consumption details, together with more detail on the effects of data rate, which has a significant effect on power consumption and signal to noise ratio. This urban study has catalogued and tested an active LoRaWAN implementation, and shows great promise for the technology in the future of the IoT, especially for long range outdoor projects. The system described here will continue to be in active use, and will provide a valuable tested resource for future projects.
Digital Article Identifier (DAI):
890
82686
Spin-Dependent Transport Signatures of Bound States: From Finger to Top Gates
Abstract:
We consider a narrow split-gate device with spin-orbit interaction and an applied in-plane magnetic field. A finger-gate or a top-gate is used to manipulate the spin-dependent electron transport properties. In the case of a finger-gate, we find that the asymmetric spin-splitting energy spectrum results in a bound state in continuum for electrons within ultralow energy regime with binding energies. In the case of top-gate, we suggest a single-mode spin injection scheme in non-ferromagnetic quantum channels utilizing perpendicular strong Rashba spin-orbit and Zeeman fields. We observe coherent destruction of transport signatures of a hole-like quasi-bound state, an electron-like quasi-bound state, or a hole-like bound state features that are sensitive to the selection of the top-gate length.
Digital Article Identifier (DAI):
889
82338
Bias Optimization of Mach-Zehnder Modulator Considering RF Gain on OFDM Radio-Over-Fiber System
Abstract:
Most of the recent wireless LANs, broadband access networks, and digital broadcasting use Orthogonal Frequency Division Multiplexing techniques. In addition, the increasing demand of Data and Internet makes fiber optics an important technology, as fiber optics has many characteristics that make it the best solution for transferring huge frames of Data from a point to another. Radio over fiber is the place where high quality RF is converted to optical signals over single mode fiber. Optimum values for the bias level and the switching voltage for Mach-Zehnder modulator are important for the performance of radio over fiber links. In this paper, we propose a method to optimize the two parameters simultaneously; the bias and the switching voltage point of the external modulator of a radio over fiber system considering RF gain. Simulation results show the optimum gain value under these two parameters.
Digital Article Identifier (DAI):
888
82337
Performance Evaluation of MIMO-OFDM Communication Systems
Abstract:
This paper evaluates the bit error rate (BER) performance of MIMO-OFDM communication system. MIMO system uses multiple transmitting and receiving antennas with different coding techniques to either enhance the transmission diversity or spatial multiplexing gain. Utilizing alamouti algorithm were the same information transmitted over multiple antennas at different time intervals and then collected again at the receivers to minimize the probability of error, combat fading and thus improve the received signal to noise ratio. While utilizing V-BLAST algorithm, the transmitted signals are divided into different transmitting channels and transferred over the channel to be received by different receiving antennas to increase the transmitted data rate and achieve higher throughput. The paper provides a study of different diversity gain coding schemes and spatial multiplexing coding for MIMO systems. A comparison of various channels' estimation and equalization techniques are given. The simulation is implemented using MATLAB, and the results had shown the performance of transmission models under different channel environments.
Digital Article Identifier (DAI):
887
82300
Complementary Metal-Oxide-Semiconductor Positive and Negative Resistor Based on Complementary Regulated Cascode Topology with Cross Coupled Regulated Transistor
Abstract:
Three types of floating active resistors are presented based on complementary regulated cascode topology with cross coupled regulated transistors. Small signal input resistance of the floating resistor is derived. Three graphs of input current versus input voltage with different aspect ratio are designed and plotted with Cadence Spectre 0.18 micron Rohm semiconductor process. Total harmonic distortion graphs are plotted with three different aspect ratios, different input voltage amplitudes and different input frequencies.
Digital Article Identifier (DAI):
886
82214
Application of the Micropolar Beam Theory for the Construction of the Discrete-Continual Model of Carbon Nanotubes
Abstract:
Together with the study of electron-optical properties of nanostructures and proceeding from experiment-based data, the study of the mechanical properties of nanostructures has become quite actual. For the study of the mechanical properties of fullerene, carbon nanotubes, graphene and other nanostructures one of the crucial issues is the construction of their adequate mathematical models. Among all mathematical models of graphene or carbon nano-tubes, this so-called discrete-continuous model is specifically important. It substitutes the interactions between atoms by elastic beams or springs. The present paper demonstrates the construction of the discrete-continual beam model for carbon nanotubes or graphene, where the micropolar beam model based on the theory of moment elasticity is accepted. With the account of the energy balance principle, the elastic moment constants for the beam model, expressed by the physical and geometrical parameters of carbon nanotube or graphene, are determined. By switching from discrete-continual beam model to the continual, the models of micropolar elastic cylindrical shell and micropolar elastic plate are confirmed as continual models for carbon nanotube and graphene respectively.
Digital Article Identifier (DAI):
885
82203
User-Based Cannibalization Mitigation in an Online Marketplace
Authors:
Abstract:
Online marketplaces are not only digital places where consumers buy and sell merchandise, but they are also destinations for brands to connect with real consumers at the moment when customers are in the shopping mindset. For many marketplaces, brands have been important partners through advertising. There can be, however, a risk of advertising impacting a consumer’s shopping journey if it hurts the user experience or takes the user away from the site. Both could lead to the loss of transaction revenue for the marketplace. In this paper, we present user-based methods for cannibalization control by selectively turning off ads to users who are likely to be cannibalized by ads subject to business objectives. We present ways of measuring cannibalization of advertising in the context of an online marketplace and propose novel ways of measuring cannibalization through purchase propensity and uplift modeling. A/B testing has shown that our methods can significantly improve user purchase and engagement metrics while operating within business objectives. To our knowledge, this is the first paper that addresses cannibalization mitigation at the user-level in the context of advertising.
Digital Article Identifier (DAI):
884
81967
The Excess Loop Delay Calibration in a Bandpass Continuous-Time Delta Sigma Modulators Based on Q-Enhanced LC Filter
Abstract:
The Q-enhanced LC filters are the most used architecture in the Bandpass (BP) Continuous-Time (CT) Delta-Sigma (SD) modulators, due to their high frequencies operation, high linearity than the active filters and a high-quality factor obtained by Q-enhanced technique. This technique consists of the use of a negative resistance that compensates the ohmic losses in the on-chip inductor. However, this technique introduces a zero in the filter transfer function which will affect the modulator performances in term of Dynamic Range (DR), stability and in-band noise (Signal-to-Noise Ratio (SNR)). In this paper, we study the effect of this zero, and we demonstrate that a calibration of the excess loop delay (ELD) is required to ensure the best performances of the modulator. System level simulations are done for a 2nd order BP CT (SD) modulator at a center frequency of 300MHz. Simulation results indicate that the optimal ELD should be reduced by 13% to achieve the maximum SNR and DR compared to the ideal LC-based SD modulator.
Digital Article Identifier (DAI):
883
81893
Conditions for Fault Recovery of Interconnected Asynchronous Sequential Machines with State Feedback
Authors:
Abstract:
In this paper, fault recovery for parallel interconnected asynchronous sequential machines is studied. An adversarial input can infiltrate into one of two submachines comprising parallel composition of the considered asynchronous sequential machine, causing an unauthorized state transition. The control objective is to elucidate the condition for the existence of a corrective controller that makes the closed-loop system immune against any occurrence of adversarial inputs. In particular, an efficient existence condition is presented that does not need the complete modeling of the interconnected asynchronous sequential machine.
Digital Article Identifier (DAI):
882
81373
A Tuning Method for Microwave Filter via Complex Neural Network and Improved Space Mapping
Abstract:
This paper presents a tuning method of microwave filter based on complex neural network and improved space mapping. The tuning process consists of two stages: the initial tuning and the fine tuning. At the beginning of the tuning, the return loss of the filter is transferred to the passband via the error of phase. During the fine tuning, the phase shift caused by the transmission line and the higher order mode is removed by the curve fitting. Then, a Cauchy method based on the admittance parameter (Y-parameter) is used to extract the coupling matrix. The influence of the resonant cavity loss is eliminated during the parameter extraction process. By using processed data pairs (the amount of screw variation and the variation of the coupling matrix), a tuning model is established by the complex neural network. In view of the improved space mapping algorithm, the mapping relationship between the actual model and the ideal model is established, and the amplitude and direction of the tuning are constantly updated. Finally, the tuning experiment of the eight order coaxial cavity filter shows that the proposed method has a good effect in tuning time and tuning precision.
Digital Article Identifier (DAI):
881
81332
A Differential Detection Method for Chip-Scale Spin-Exchange Relaxation Free Atomic Magnetometer
Abstract:
Chip-scale spin-exchange relaxation free (SERF) atomic magnetometer makes use of millimeter-scale vapor cells micro-fabricated by Micro-electromechanical Systems (MEMS) technique and SERF mechanism, resulting in the characteristics of high spatial resolution and high sensitivity. It is useful for biomagnetic imaging including magnetoencephalography and magnetocardiography. In a prevailing scheme, circularly polarized on-resonance laser beam is adapted for both pumping and probing the atomic polarization. And the magnetic-field-sensitive signal is extracted by transmission laser intensity enhancement as a result of atomic polarization increase on zero field level crossing resonance. The scheme is very suitable for integration, however, the laser amplitude modulation (AM) noise and laser frequency modulation to amplitude modulation (FM-AM) noise is superimposed on the photon shot noise reducing the signal to noise ratio (SNR). To suppress AM and FM-AM noise the paper puts forward a novel scheme which adopts circularly polarized on-resonance light pumping and linearly polarized frequency-detuning laser probing. The transmission beam is divided into transmission and reflection beams by a polarization analyzer, the angle between the analyzer's transmission polarization axis and frequency-detuning laser polarization direction is set to 45°. The magnetic-field-sensitive signal is extracted by polarization rotation enhancement of frequency-detuning laser which induces two beams intensity difference increase as the atomic polarization increases. Therefore, AM and FM-AM noise in two beams are common-mode and can be almost entirely canceled by differential detection. We have carried out an experiment to study our scheme. The experiment reveals that the noise in the differential signal is obviously smaller than that in each beam. The scheme is promising to be applied for developing more sensitive chip-scale magnetometer.
Digital Article Identifier (DAI):
880
80571
A Low Profile Dual Polarized Slot Coupled Patch Antenna
Abstract:
A low profile, dual polarized, slot coupled patch antenna is designed and developed in this paper. The proposed antenna has a measured bandwidth of 17.2% for return loss > 15dB and pair ports isolation > 23dB. The gain of the antenna is over 10dBi and the half power beam widths (HPBW) of the antenna are 80 ± 3ᵒ in the horizontal plane and 39 ± 2ᵒ in the vertical plane. The cross polarization discrimination (XPD) is less than 20dB in HPBW. Within the operating band, the performances of good impedance match, high ports isolation, low cross polarization, and stable radiation patterns are achieved.
Digital Article Identifier (DAI):
879
80510
Performance Analysis of Fractional Frequency Reuse Based Non Orthogonal Spectrum Shared Single Input Multiple Output Systems
Abstract:
In non-orthogonal spectrum sharing, the frequency bands are allocated simultaneously to more than one operator, which could cause a degradation of signal to interference ratio (SIR) at the intended receivers. In order to improve the SIR, we propose a fractional frequency reuse (FFR) based structure for non-orthogonal spectrum shared (NOSS) systems. The expressions of coverage probability and average rate are derived for the proposed FFR based NOSS systems, and it is shown that the proposed scheme ensures higher sum rate when compared to no spectrum shared system, without any significant degradation in coverage probability.
Digital Article Identifier (DAI):
878
80363
Experimentally Validated Analytical Model for Thermal Analysis of Multi-Stage Depressed Collector
Abstract:
Multi-stage depressed collectors (MDC) are used as an efficiency enhancement technique in traveling wave tubes the high-energy electron beam, after its interaction with the RF signal, gets velocity sorted and collected at various depressed electrodes of the MDC. The ultimate goal is to identify an optimum thermal management scheme (cooling mechanism) that could extract the heat efficiently from the electrodes. Careful thermal analysis, incorporating the cooling mechanism is required to ensure that the maximum temperature does not exceed the safe limits. A simple analytical model for quick prediction of the thermal has been developed. The model has been developed for the worst-case un-modulated DC condition, where all the thermal power is dissipated in the last electrode (typically, fourth electrode in the case of the four-stage depressed collector). It considers the thermal contact resistances at various braze joints accounting for the practical non-uniformities. Analytical results obtained from the model have been validated with simulated and experimental results.
Digital Article Identifier (DAI):
877
80264
Support Vector Machine Based Tool to Aid the Diagnosis of Multiple Sclerosis Using Commercial Electromyography Sensor
Abstract:
Multiple sclerosis (MS) is a major auto-immune disease that is the leading cause of non-traumatic impairment of central nervous system in young adults. Success in managing its symptoms and in recovering from the attacks highly depends on accurate medical diagnosis made in advance. The neurological examination is an expert procedure including several different tests and examinations that, despite its complexity, lacks precision. This work gives an investigation of the capabilities of a commercial electromyographic and inertial sensor (MYO Armband by Thalmic Labs Inc.) during the neurological examination. In this initial study, a dataset of electromyographic signals from 71 individuals (including 31 diagnosed with MS and 40 healthy subjects) was firstly acquired under classical conditions of MS diagnosing procedure. Temporal and spectral features of the signals are then extracted in order to train and validate several classification algorithms. A classification rate of 88% was finally obtained using Support Vector Machine. Together with clinicians we propose a set of signal descriptors that correlates with objective components of the neurological examination. The proposed technique, being non-disruptive, simple and easily affordable, is considered to have high potential in aiding the MS diagnosing.
Digital Article Identifier (DAI):
876
80068
MCERTL: Mutation-Based Correction Engine for Register-Transfer Level Designs
Authors:
Abstract:
In this paper, we present MCERTL (mutation-based correction engine for RTL designs) as an automatic error correction technique based on mutation analysis. A mutation-based correction methodology is proposed to automatically fix the erroneous RTL designs. The proposed strategy combines the processes of mutation and assertion-based localization. The erroneous statements are mutated to produce possible fixes for the failed RTL code. A concurrent mutation engine is proposed to mitigate the computational cost of running sequential mutants operators. The proposed methodology is evaluated against some benchmarks. The experimental results demonstrate that our proposed method enables us to automatically locate and correct multiple bugs at reasonable time.
Digital Article Identifier (DAI):
875
79954
International and Intercultural Communication Design: Case Study of Manipulative Advertising
Authors:
Abstract:
The purpose of the following research paper is to discuss the differentiating meanings of culture and how popular culture has maintained a great impact on intercultural and international behavior. The following discussion leads to the notion of communicating cultural impact on behavior through advertising and sub-cultural theory in advertising. Although towards the end of the research, the complexities that develop through the above discussion, lead to the solution that ‘advertising gives meaning to the otherwise meaningless and identical objects through linking them to our basic needs’. In today’s fast paced digital world, it is difficult to define culture, literally, since its meaning tends to shift through series of different perceptions such as ‘how’ and ‘why’ it should be used. This notion can be taken towards another notion of popular culture. It is dependent on ‘attitudes, ideas, images, perspectives and other phenomena within the mainstream of a given culture’. Since popular culture is influenced by mass media, it has a way of influencing an individual’s attitude towards certain topics. For example, tattoos are a form of human decorations, that have historic significance, and a huge spectrum of meanings. Advertising is one aspect of marketing that has evolved from the time when it was ‘production oriented’, up till the time it started using different mediums to make its impact more effective. However, this impact has confused us between our needs and desires. The focus in this paper is ‘we consume to acquire a sense of social identity and status, not just for the sake of consumption’. Every culture owns different expressions, which are then used by advertisers to create its impact on the behavior of people sub-culturally and globally, as culture grows through social interaction. Advertisers furthermore play a smart role in highlighting quality of life ranging from ‘survival to well-being’. Hence, this research paper concludes by highlighting that culture is considered as a ‘basic root’ of any community that also provides solution to certain problems; however, advertisers play their part in manipulating society’s literacy and beliefs by rationalizing how relevant certain products/brands are to their beliefs.
Digital Article Identifier (DAI):
874
79688
Enhancement of Primary User Detection in Cognitive Radio by Scattering Transform
Abstract:
The detecting of an occupied frequency band is a major issue in cognitive radio systems. The detection process becomes difficult if the signal occupying the band of interest has faded amplitude due to multipath effects. These effects make it hard for an occupying user to be detected. This work mitigates the missed-detection problem in the context of cognitive radio in frequency-selective fading channel by proposing blind channel estimation method that is based on scattering transform. By initially applying conventional energy detection, the missed-detection probability is evaluated, and if it is greater than or equal to 50%, channel estimation is applied on the received signal followed by channel equalization to reduce the channel effects. In the proposed channel estimator, we modify the Morlet wavelet by using its first derivative for better frequency resolution. A mathematical description of the modified function and its frequency resolution is formulated in this work. The improved frequency resolution is required to follow the spectral variation of the channel. The channel estimation error is evaluated in the mean-square sense for different channel settings, and energy detection is applied to the equalized received signal. The simulation results show improvement in reducing the missed-detection probability as compared to the detection based on principal component analysis. This improvement is achieved at the expense of increased estimator complexity, which depends on the number of wavelet filters as related to the channel taps. Also, the detection performance shows an improvement in detection probability for low signal-to-noise scenarios over principal component analysis- based energy detection.
Digital Article Identifier (DAI):
873
79237
Field Programmable Gate Array Implementation of Adaptive Clock Recovery for Time Division Multiplexing over Internet Protocol Systems
Abstract:
Circuit switched networks widely used until the end of the 20th century have been transformed into packages switched networks. Time Division Multiplexing over Internet Protocol (TDMoIP) is a system that enables Time Division Multiplexing (TDM) traffic to be carried over packet switched networks (PSN). In TDMoIP systems, devices that send TDM data to the PSN and receive it from the network must operate with the same clock frequency. In this study, it was aimed to implement clock synchronization process in Field Programmable Gate Array (FPGA) chips using time information attached to the packages received from PSN. The designed hardware is verified using the data sets obtained for the different carrier types and comparing the results with the software model. Field tests are also performed by using the real time TDMoIP system.
Digital Article Identifier (DAI):
872
79232
Red Green Blue Image Encryption Based on Paillier Cryptographic System
Abstract:
In this paper, we present a novel application of the Paillier cryptographic system to the encryption of RGB (Red Green Blue) images. In this method, an RGB image is first separated into its constituent channel images, and the Paillier encryption function is applied to each of the channels pixel intensity values. Next, the encrypted image is combined and compressed if necessary before being transmitted through an unsecured communication channel. The transmitted image is subsequently recovered by a decryption process. We performed a series of security and performance analyses to the recovered images in order to verify their robustness to security attack. The results show that the proposed image encryption scheme produces highly secured encrypted images.
Digital Article Identifier (DAI):
871
79041
A CMOS-Integrated Hall Plate with High Sensitivity
Abstract:
An improved cross-shaped hall plate with high sensitivity is described in this paper. Among different geometries that have been simulated and measured using Helmholtz coil. The paper describes the physical hall plate design and implementation in a 0.18-µm CMOS technology. In this paper, the biasing is a constant voltage mode. In the voltage mode, magnetic field is converted into an output voltage. The output voltage is typically in the order of micro- to millivolt and therefore, it must be amplified before being transmitted to the outside world. The study, design and performance optimization of hall plate has been carried out with the COMSOL Multiphysics. It is used to estimate the voltage distribution in the hall plate with and without magnetic field and to optimize the geometry. The simulation uses the nominal bias current of 1mA. The applied magnetic field is in the range from 0 mT to 20 mT. Measured results of the one structure over the 10 available samples show for the best sensitivity of 2.5 %/T at 20mT.
Digital Article Identifier (DAI):
870
78900
A Microwave and Millimeter-Wave Transmit/Receive Switch Subsystem for Communication Systems
Abstract:
Multi-band systems offer a great deal of benefit in modern communication and radar systems. In particular, multi-band antenna-array radar systems with their extended frequency diversity provide numerous advantages in detection, identification, locating and tracking a wide range of targets, including enhanced detection coverage, accurate target location, reduced survey time and cost, increased resolution, improved reliability and target information. An accurate calibration is a critical issue in antenna array systems. The amplitude and phase errors in multi-band and multi-polarization antenna array transceivers result in inaccurate target detection, deteriorated resolution and reduced reliability. Furthermore, the digital beam former without the RF domain phase-shifting is less immune to unfiltered interference signals, which can lead to receiver saturation in array systems. Therefore, implementing integrated front-end architecture, which can support calibration function with low insertion and filtering function from the farthest end of an array transceiver is of great interest. We report a dual K/Ka-band T/R/Calibration switch module with quasi-elliptic dual-bandpass filtering function implementing a Q-enhanced metamaterial transmission line. A unique dual-band frequency response is incorporated in the reception and calibration path of the proposed switch module utilizing the composite right/left-handed meta material transmission line coupled with a Colpitts-style negative generation circuit. The fabricated fully integrated T/R/Calibration switch module in 0.18-μm BiCMOS technology exhibits insertion loss of 4.9-12.3 dB and isolation of more than 45 dB in the reception, transmission and calibration mode of operation. In the reception and calibration mode, the dual-band frequency response centered at 24.5 and 35 GHz exhibits out-of-band rejection of more than 30 dB compared to the pass bands below 10.5 GHz and above 59.5 GHz. The rejection between the pass bands reaches more than 50 dB. In all modes of operation, the IP1-dB is between 4 and 11 dBm. Acknowledgement: This paper was made possible by NPRP grant # 6-241-2-102 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.
Digital Article Identifier (DAI):
869
78898
Millimeter-Wave Silicon Power Amplifiers for 5G Wireless Communications
Abstract:
Exploding demands for more data, faster data transmission speed, less interference, more users, more wireless devices, and better reliable service-far exceeding those provided in the current mobile communications networks in the RF spectrum below 6 GHz-has led the wireless communication industry to focus on higher, previously unallocated spectrums. High frequencies in RF spectrum near (around 28 GHz) or within the millimeter-wave regime is the logical solution to meet these demands. This high-frequency RF spectrum is of increasingly important for wireless communications due to its large available bandwidths that facilitate various applications requiring large-data high-speed transmissions, reaching up to multi-gigabit per second, of vast information. It also resolves the traffic congestion problems of signals from many wireless devices operating in the current RF spectrum (below 6 GHz), hence handling more traffic. Consequently, the wireless communication industries are moving towards 5G (fifth generation) for next-generation communications such as mobile phones, autonomous vehicles, virtual reality, and the Internet of Things (IoT). The U.S. Federal Communications Commission (FCC) proved on 14th July 2016 three frequency bands for 5G around 28, 37 and 39 GHz. We present some silicon-based RFIC power amplifiers (PA) for possible implementation for 5G wireless communications around 28, 37 and 39 GHz. The 16.5-28 GHz PA exhibits measured gain of more than 34.5 dB and very flat output power of 19.4±1.2 dBm across 16.5-28 GHz. The 25.5/37-GHz PA exhibits gain of 21.4 and 17 dB, and maximum output power of 16 and 13 dBm at 25.5 and 37 GHz, respectively, in the single-band mode. In the dual-band mode, the maximum output power is 13 and 9.5 dBm at 25.5 and 37 GHz, respectively. The 10-19/23-29/33-40 GHz PA has maximum output powers of 15, 13.3, and 13.8 dBm at 15, 25, and 35 GHz, respectively, in the single-band mode. When this PA is operated in dual-band mode, it has maximum output powers of 11.4/8.2 dBm at 15/25 GHz, 13.3/3 dBm at 15/35 GHz, and 8.7/6.7 dBm at 25/35 GHz. In the tri-band mode, it exhibits 8.8/5.4/3.8 dBm maximum output power at 15/25/35 GHz. Acknowledgement: This paper was made possible by NPRP grant # 6-241-2-102 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors
Digital Article Identifier (DAI):