International Science Index

International Journal of Electronics and Communication Engineering

Resistive Switching Characteristics of Resistive Random Access Memory Devices after Furnace Annealing Processes
In this study, the resistive random access memory devices with the TiN/Ti/HfOx/TiN structure were fabricated, then the electrical characteristics of the devices without annealing and after 400 °C and 500 °C of the furnace annealing (FA) temperature processes were compared. The RRAM devices after the FA’s 400 °C showed the lower forming, set and reset voltages than the other devices without annealing. However, the RRAM devices after the FA’s 500 °C did not show any electrical characteristics because the TiN/Ti/HfOx/TiN device was oxidized, as shown in the XPS analysis. From these results, the RRAM devices after the FA’s 400°C showed the best electrical characteristics.
Enhanced Dielectric and Ferroelectric Properties in Holmium Substituted Stoichiometric and Non-Stoichiometric SBT Ferroelectric Ceramics
A large number of ferroelectric materials have been intensely investigated for applications in non-volatile ferroelectric random access memories (FeRAMs), piezoelectric transducers, actuators, pyroelectric sensors, high dielectric constant capacitors, etc. Bismuth layered ferroelectric materials such as Strontium Bismuth Tantalate (SBT) has attracted a lot of attention due to low leakage current, high remnant polarization and high fatigue endurance up to 1012 switching cycles. However, pure SBT suffers from various major limitations such as high dielectric loss, low remnant polarization values, high processing temperature, bismuth volatilization, etc. Significant efforts have been made to improve the dielectric and ferroelectric properties of this compound. Firstly, it has been reported that electrical properties vary with the Sr/ Bi content ratio in the SrBi2Ta2O9 compsition i.e. non-stoichiometric compositions with Sr-deficient / Bi excess content have higher remnant polarization values than stoichiometic SBT compositions. With the objective to improve structural, dielectric, ferroelectric and piezoelectric properties of SBT compound, rare earth holmium (Ho3+) was chosen as a donor cation for substitution onto the Bi2O2 layer. Moreover, hardly any report on holmium substitution in stoichiometric SrBi2Ta2O9 and non-stoichiometric Sr0.8Bi2.2Ta2O9 compositions were available in the literature. The holmium substituted SrBi2-xHoxTa2O9 (x= 0.00-2.0) and Sr0.8Bi2.2Ta2O9 (x=0.0 and 0.01) compositions were synthesized by the solid state reaction method. The synthesized specimens were characterized for their structural and electrical properties. X-ray diffractograms reveal single phase layered perovskite structure formation for holmium content in stoichiometric SBT samples up to x ≤ 0.1. The granular morphology of the samples was investigated using scanning electron microscope (Hitachi, S-3700 N). The dielectric measurements were carried out using a precision LCR meter (Agilent 4284A) operating at oscillation amplitude of 1V. The variation of dielectric constant with temperature shows that the Curie temperature (Tc) decreases on increasing the holmium content. The specimen with x=2.0 i.e. the bismuth free specimen, has very low dielectric constant and does not show any appreciable variation with temperature. The dielectric loss reduces significantly with holmium substitution. The polarization–electric field (P–E) hysteresis loops were recorded using a P–E loop tracer based on Sawyer–Tower circuit. It is observed that the ferroelectric property improve with Ho substitution. Holmium substituted specimen exhibits enhanced value of remnant polarization (Pr= 9.22 μC/cm²) as compared to holmium free specimen (Pr= 2.55 μC/cm²). Piezoelectric co-efficient (d33 values) was measured using a piezo meter system (Piezo Test PM300). It is observed that holmium substitution enhances piezoelectric coefficient. Further, the optimized holmium content (x=0.01) in stoichiometric SrBi2-xHoxTa2O9 composition has been substituted in non-stoichiometric Sr0.8Bi2.2Ta2O9 composition to obtain further enhanced structural and electrical characteristics. It is expected that a new class of ferroelectric materials i.e. Rare Earth Layered Structured Ferroelectrics (RLSF) derived from Bismuth Layered Structured Ferroelectrics (BLSF) will generate which can be used to replace static (SRAM) and dynamic (DRAM) random access memories with ferroelectric random access memories (FeRAMS).
Cost Analysis of Optimized Fast Network Mobility in Ieee 802.16e Networks
To support group mobility, the NEMO Basic Support Protocol has been standardized as an extension of Mobile IP that enables an entire network to change its point of attachment to the Internet. The NEMO protocol can support network mobility in IEEE 802.16e networks, but it causes negative effect on handover latency performance which is not negligible for real-time applications. In this paper, we propose an integrated scheme that combine cross layer design and cross function optimization to improve the handover latency. In the Optimized Fast NEMO (OFNEMO) the relative messages of both, L2 handover in IEEE 802.16e and L3 handover in Fast Mobile IPv6 and the NEMO Basic Support are merged. Also a pre-established tunnels concept is used to reduce service disruption time. An analytical model is developed to evaluate total cost consisting of signaling and packet delivery costs of the OFNEMO compared with RFC3963. Results show that OFNEMO increases probability of predictive mode compared with RFC3963 due to smaller handover latency. Even though OFNEMO needs extra signalling to pre-establish multi tunnel, it has less total cost thanks to its optimized algorithm. OFNEMO can minimize handover latency for supporting real time application in moving networks.
VoIP QoS Evaluation for Mobile Ad Hoc Network in an Indoor Environment for Different Voice Codecs
In this paper, the performance and quality of VoIP calls carried over a Mobile Ad Hoc Network (MANET) which has a number of SIP nodes registered on a SIP Proxy are analyzed. The testing campaigns are carried out in an indoor corridor structure having a well-defined channel’s characteristics and model for the different voice codecs, G.711, G.727 and G.723.1. These voice codecs are commonly used in VoIP technology. The calls’ quality are evaluated using four QoS metrics, namely, mean opinion score (MOS), jitter, delay, and packet loss. The relationship between the wireless channel’s parameters and the optimum codec is well-established. According to the experimental results, the voice codec G.711 has the best performance for the proposed MANET topology.
Characteristics of GaAs/InGaP and AlGaAs/GaAs/InAlGaP Npn Heterostructural Optoelectronic Switches
Optoelectronic switches have attracted a considerable attention in the semiconductor research field due to their potential applications in optical computing systems and optoelectronic integrated circuits (OEICs). With high gains and high-speed operations, npn heterostructures can be used to produce promising optoelectronic switches. It is known that the bulk barrier and heterostructure-induced potential spike act important roles in the characteristics of the npn heterostructures. To investigate the effects of bulk barrier and potential spike heights on the optoelectronic switching of the npn heterostructures, GaAs/InGaP and AlGaAs/GaAs/InAlGaP npn heterostructural optoelectronic switches (HSOSs) have been fabricated in this work. It is seen that the illumination decreases the switching voltage Vs and increases the switching current Is, and thus the OFF state is under dark and ON state under illumination in the optical switching of the GaAs/InGaP HSOS characteristics. But in the AlGaAs/GaAs/InAlGaP HSOS characteristics, the Vs and Is present contrary trends, and the OFF state is under illumination and ON state under dark. The studied HSOSs show quite different switching variations with incident light, which are mainly attributed to the bulk barrier and potential spike heights affected by photogenerated carriers.
Investigation of Length Effect on Power Conversion Efficiency of Perovskite Solar Cells Composed of ZnO Nanowires
The power conversion efficiency (PCE) of the perovskite solar cells has been achieved by inserting vertically-aligned ZnO nanowires (NWs) between the cathode and the active layer and shows better solar cells performance. Perovskite solar cells have drawn significant attention due to the superb efficiency and low-cost fabrication process. In this experiment, ZnO nanowires are used as the electron transport layer (ETL) due to its low temperature process. The main idea of this thesis is utilizing the 3D structures of the hydrothermally-grown ZnO nanowires to increase the junction area to improve the photovoltaic performance of the perovskite solar cells. The infiltration and the surface coverage of the perovskite precursor solution changed as tuning the length of the ZnO nanowires. It is revealed that the devices with ZnO nanowires of 150 nm demonstrated the best PCE of 8.46 % under the AM 1.5G illumination (100 mW/cm2).
Radar Cross Section Modelling of Lossy Dielectrics
Radar cross section (RCS) of dielectric objects play an important role in many applications, such as low observability technology development, drone detection, and monitoring as well as coastal surveillance. Various materials are used to construct the targets of interest such as metal, wood, composite materials, radar absorbent materials, and other dielectrics. Since simulated datasets are increasingly being used to supplement infield measurements, as it is more cost effective and a larger variety of targets can be simulated, it is important to have a high level of confidence in the predicted results. Confidence can be attained through validation. Various computational electromagnetic (CEM) methods are capable of predicting the RCS of dielectric targets. This study will extend previous studies by validating full-wave and asymptotic RCS simulations of dielectric targets with measured data. The paper will provide measured RCS data of a number of canonical dielectric targets exhibiting different material properties. As stated previously, these measurements are used to validate numerous CEM methods. The dielectric properties are accurately characterized to reduce the uncertainties in the simulations. Finally, an analysis of the sensitivity of oblique and normal incidence scattering predictions to material characteristics is also presented. In this paper, the ability of several CEM methods, including method of moments (MoM), and physical optics (PO), to calculate the RCS of dielectrics were validated with measured data. A few dielectrics, exhibiting different material properties, were selected and several canonical targets, such as flat plates and cylinders, were manufactured. The RCS of these dielectric targets were measured in a compact range at the University of Pretoria, South Africa, over a frequency range of 2 to 18 GHz and a 360° azimuth angle sweep. This study also investigated the effect of slight variations in the material properties on the calculated RCS results, by varying the material properties within a realistic tolerance range and comparing the calculated RCS results. Interesting measured and simulated results have been obtained. Large discrepancies were observed between the different methods as well as the measured data. It was also observed that the accuracy of the RCS data of the dielectrics can be frequency and angle dependent. The simulated RCS for some of these materials also exhibit high sensitivity to variations in the material properties. Comparison graphs between the measured and simulation RCS datasets will be presented and the validation thereof will be discussed. Finally, the effect that small tolerances in the material properties have on the calculated RCS results will be shown. Thus the importance of accurate dielectric material properties for validation purposes will be discussed.
Validation of Asymptotic Techniques to Predict Bistatic Radar Cross Section
Simulations are commonly used to predict the bistatic radar cross section (RCS) of military targets since characterization measurements can be expensive and time consuming. It is thus important to accurately predict the bistatic RCS of targets. Computational electromagnetic (CEM) methods can be used for bistatic RCS prediction. CEM methods are divided into full-wave and asymptotic methods. Full-wave methods are numerical approximations to the exact solution of Maxwell’s equations. These methods are very accurate but are computationally very intensive and time consuming. Asymptotic techniques make simplifying assumptions in solving Maxwell's equations and are thus less accurate but require less computational resources and time. Asymptotic techniques can thus be very valuable for the prediction of bistatic RCS of electrically large targets, due to the decreased computational requirements. This study extends previous work by validating the accuracy of asymptotic techniques to predict bistatic RCS through comparison with full-wave simulations as well as measurements. Validation is done with canonical structures as well as complex realistic aircraft models instead of only looking at a complex slicy structure. The slicy structure is a combination of canonical structures, including cylinders, corner reflectors and cubes. Validation is done over large bistatic angles and at different polarizations. Bistatic RCS measurements were conducted in a compact range, at the University of Pretoria, South Africa. The measurements were performed at different polarizations from 2 GHz to 6 GHz. Fixed bistatic angles of β = 30.8°, 45° and 90° were used. The measurements were calibrated with an active calibration target. The EM simulation tool FEKO was used to generate simulated results. The full-wave multi-level fast multipole method (MLFMM) simulated results together with the measured data were used as reference for validation. The accuracy of physical optics (PO) and geometrical optics (GO) was investigated. Differences relating to amplitude, lobing structure and null positions were observed between the asymptotic, full-wave and measured data. PO and GO were more accurate at angles close to the specular scattering directions and the accuracy seemed to decrease as the bistatic angle increased. At large bistatic angles PO did not perform well due to the shadow regions not being treated appropriately. PO also did not perform well for canonical structures where multi-bounce was the main scattering mechanism. PO and GO do not account for diffraction but these inaccuracies tended to decrease as the electrical size of objects increased. It was evident that both asymptotic techniques do not properly account for bistatic structural shadowing. Specular scattering was calculated accurately even if targets did not meet the electrically large criteria. It was evident that the bistatic RCS prediction performance of PO and GO depends on incident angle, frequency, target shape and observation angle. The improved computational efficiency of the asymptotic solvers yields a major advantage over full-wave solvers and measurements; however, there is still much room for improvement of the accuracy of these asymptotic techniques.
Communication and Devices: Face to Face Communication versus Communication with Mobile Technologies
With the rapid changes occurring in the last twenty-five years, mobile phone technology has influenced every aspect of life. Prevalence in the Android and smartphone use have been affected almost in every area throughout the world; business strategies; way to access information; interpersonal communications; everyday life practices; political issues; economic issues; social issues; etc. The financial power of individual; the infrastructure; and the regulation of the country are the main factors which determine the usage capacity of technology in a country. If the situational factors which are identified above are convenient in countries, the decisions of people in many subjects can easily be formed by the opportunities which are provided by the Internet. Technological developments within the Internet and mobile phone areas have not only changed communication practices; it has also changed the everyday life practices of individuals. This article has focused on understanding how people’s communication practices and everyday life practices have changed with Android and the smartphone usage. The study was conducted by using deep interview methods and having interviews with twenty people. The deep interview was conducted to get detailed information from the participants as a research method. Each generation does not get affected from technological developments in the same way, that's the reason for attempting to establish such an age range in the research. Communicating with each other (face to face, via internet) is in the scope of interpersonal communication. Interpersonal communication subject is the matter of private space. To get satisfactory and detailed answers, deep interview was the correct research method to practice. The research was conducted on twenty Turkish Cypriots who lives in Northern Cyprus. The research was held within 1-31 July 2016 period. Cyprus is an island in the middle of the Mediterranean Sea which has been divided into two parts as south and north after the war in 1974. In the south side, Greek Cypriots and in the north side Turkish Cypriot live. This study has focused on the Turkish Cypriot society living in Northern Cyprus. Turkish Republic of Northern Cyprus was declared in 1983. Turkish Republic of Northern Cyprus is not recognized by any country except Turkey. This results in the isolation of Northern Cyprus economically and politically all over the world. According to the research results, communicating via Internet has rapidly replaced face to face communication in recent years. However, results have changed according to generations. Elder generations met with digital technology in late ages, but younger generations (especially generation Z) have been born into the digital age. Younger generations can easily adapt themselves to technological changes because they are already gaining everyday life practices right now. However, the older generations practices are already present in their everyday life. Each change in technology can cause new habits to gain for everyone. As mobile phones and smartphone usage and communicating with internet increases, every generation must adapt themselves to the technological developments according to the needs and possibilities that they have.
Content-Based Mammograms Retrieval Based on Breast Density Criteria Using Bidimensional Empirical Mode Decomposition
Most medical images, and especially mammographies, are now stored in large databases. Retrieving a desired image is considered of great importance in order to find previous similar cases diagnosis. Our method is implemented to assist radiologists in retrieving mammographic images containing breast with similar density aspect as seen on the mammogram. This is becoming a challenge seeing the importance of density criteria in cancer provision and its effect on segmentation issues. We used the BEMD (Bidimensional Empirical Mode Decomposition) to characterize the content of images and Euclidean distance measure similarity between images. Through the experiments on the MIAS mammography image database, we confirm that the results are promising. The performance was evaluated using precision and recall curves comparing query and retrieved images. Computing recall-precision proved the effectiveness of applying the CBIR in the large mammographic image databases. We found a precision of 91.2% for mammography with a recall of 86.8%.
Design of an Electronic Control Unit for High-Resolution Headlight Systems
Camera-based intelligent light systems enable specific light distributions adjusting horizontal and vertical directions and shape by the use of a few actuators and a light source. The introduction of segmented headlights allows activating high beam in more situations while other traffic participants are masked and not blended. Now, development of modern headlight systems comes closer to a new phase. The number of segments increases up to tens of thousands to make new driver assistance functions possible. In addition, actuators can be replaced since the light distributions are highly flexible by adjusting the brightness of each segment, so-called pixel. Not only the E/E Architecture needs to be adapted to new requirements of high data rates, but also high-resolution headlight systems need an appropriate electronic unit, which is able to supply and control the light sources. In this paper, different additive and subtractive light systems getting ready for the market are presented and an electronic control unit is designed and evaluated. Possibilities of improving EMC and safety are considered.
A Color Parameterized Logarithmic Image Processing Model (COPLIP) and Its Application in Image Enhancement
With the development of logarithmic model, image processing research based on the logarithmic model is becoming more and more important. This paper proposes a new model of color parameterized logarithmic image processing (COPLIP). First, color tone function of color images is defined. Second, operations of addition, multiplication, inversion and subtraction on tone functions are proposed. Third, the concept of fundamental homomorphism function is defined. The new model can not only match human visual model, but also select more parameters to process images. To verify the validity of the COPLIP model, this paper applies the model to image enhancement and forms COPLIP-image enhancement algorithm which have a good effect on images. Experiments show that the new model proposed outperforms existing color logarithmic image processing model with wide applications.
Force Measurement for E-Cadherin-Mediated Intercellular Adhesion Probed by Protein Micropattern and Traction Force Microscopy
Cell’s mechanical forces provide important physical cues in regulation of proper cellular functions, such as cell differentiation, proliferation and migration. It is believed that adhesive forces generated by cell-cell interaction are able to transmit to the interior of cell through filamentous cortical cytoskeleton. Prominent among other membrane receptors, Cadherins are prototypical adhesive molecules able to generate remarkable forces to regulate intercellular adhesion. However, the mechanistic steps of mechano-transduction in Cadherin-mediated adhesion remain very controversial. We are interested in understanding how Cadherin protein complexes enable force generation and transmission at cell-cell contact in the initial stage of intercellular adhesion. For providing a better control of time, space, and substrate stiffness, in this study, a combination of protein micropattern, micropipette manipulation, and traction force microscopy is used. Pair micropattern with different forms confines cell spreading area and the gaps in pairs varied from 2 to 8 microns are applied for monitoring the forces that cell pairs generated, measured by traction force microscopy. Moreover, cell clones obtained from epithelial cells undergone genome editing are used to score the importance for known components of Cadherin complexes in force generation. We believe that our results from this combinatory mechanobiological method will provide deep insights on understanding the biophysical principle governing mechano- transduction of Cadherin-mediated intercellular adhesion.
Electrical and Structural Properties of Polyaniline-Fullerene Nanocomposite
In recent years, composites of conjugated polymers with fullerenes (C60) has attracted considerable scientific and technological attention in the field of organic electronics because they possess a novel combination of electrical, optical, ferromagnetic, mechanical and sensor properties. These properties represent major advances in the design of organic electronic devices. With the addition of C60 in the conjugated polymer matrix, the primary photo-excitation of the conjugated polymer undergoes an ultrafast electron transfer, and it has been demonstrated that fullerene molecules may serve as efficient electron acceptors in polymeric solar cells. The present paper includes the systematic studies on the effect of electrical, structural and sensor properties of polyaniline (PANI) matrix by the presence of C60. Polyaniline-fullerene (PANI/C60) composite is prepared by the introduction of fullerene during polymerization of aniline with ammonium persulfate and dodechyl benzene sulfonic acid as oxidant and dopant respectively. FTIR spectroscopy indicated the interaction between PANI and C60. X-ray diffraction proved the formation of a PANI/C60 complex. SEM image shows the highly branched chain structure of the PANI in the presence of C60. The conductivity of the PANI/C60 was found to be more than ten orders of magnitude over the pure PANI.
A Model-Based Automatic Task Parallelization Approach Using Adapted Scheduling Algorithm in Multi-Core Real-Time Embedded Systems
Automated driving, zero emission, connected cars and further advanced functionalities in vehicles highly demand the use of multi-core processors. Besides the benefits of more computation power, the challenge of multi-core processors is not only handling the effects due to parallel execution of the application but also allowing the system to run in full core utilization with tolerable hardware and operating systems overheads. On the other hand, the existing single-core projects address the need of automatized system designs approaches for reducing the design effort while migrating to multi-core platform. This work presents a model-based optimization approach for automatic task parallelization and an adapted multi-core scheduling algorithm for an embedded real-time system. We couple the automatic task parallelization approach using a multi-core scheduling algorithm for reducing overheads caused by synchronization for data exchange, hardware and operating system which highly impacts the performance of the parallel execution of tasks in a hard real-time system. In the case studies, we compare the execution of a parallelized system using a static scheduling approach and the proposed adapted scheduling approach. We show that the coupling of the parallelized system with an efficient scheduling algorithm is essential, as it allows a parallel system to run in a multi-core processor more efficiently and with the least overheads.
Exploration of Various Metrics for Partitioning of Cellular Automata Units for Efficient Reconfiguration of Field Programmable Gate Arrays (FPGAs)
Using FPGA devices to improve the behavior of time-critical parts of embedded systems is a proven concept for years. With reconfigurable FPGA devices, the logical blocks can be partitioned and grouped into static and dynamic parts. The dynamic parts can be reloaded 'on demand' at runtime. This work uses cellular automata, which are constructed through compilation from (partially restricted) ANSI-C sources, to determine the suitability of various metrics for optimal partitioning. Significant metrics, in this case, are for example the area on the FPGA device for the partition, the pass count for loop constructs and communication characteristics to other partitions. With successful partitioning, it is possible to use smaller FPGA devices for the same requirements as with not reconfigurable FPGA devices or – vice versa – to use the same FPGAs for larger programs.
Rail-To-Rail Output Op-Amp Design with Negative Miller Capacitance Compensation
In this paper, a two-stage op-amp design is considered using both Miller and negative Miller compensation techniques. The first op-amp design uses Miller compensation around the second amplification stage whilst the second op-amp design uses negative Miller compensation around the first stage and Miller compensation around the second amplification stage. The aims of this work were to compare the gain and phase margins attained using the different compensation techniques and identify the ability to choose either compensation technique based on a particular set of design requirements. The two op-amp designs created are based on the same two-stage rail-to-rail output CMOS op-amp architecture where the first stage of the op-amp consists of differential input and cascode circuits, and the second stage is a class AB amplifier. The op-amps have been designed using a 0.35um CMOS fabrication process.
Electromagnetic Assessment of Submarine Power Cable Degradation Using Finite Element Method and Sensitivity Analysis
Offshore wind conversion represents one of the most important and the fastest growing resource for electric power generation. Submarine power cables are part of the electric collection and transmission grid which harvests the power produced by the wind farms and carry it to the shore. Maintenance of submarine power cables is proved difficult because of water depth, marine conditions and large length of the transmission links. Faults on submarine power cables can occur during transport, installation and operating under high voltage power. The risks encountered can be related to natural ageing or unforeseen events such as ships anchoring. Submarine power cables are made of three coaxial cores, polymer insulated, copper or lead sheathed, steel armoured with some other layers insuring the proper cable functioning. They can be placed in a flat or trefoil formations. In this paper, we investigate the fault initiators for short and long term cable failure prediction by means of an electromagnetic analysis. The finite element method is used to solve the Maxwell’s equations in low frequency, where the wavelength is greater than the cable dimensions. Damage is represented as a fault or heterogeneity characterized by its shape, location and material. In order to determine the most contributing damage characteristics to the electromagnetic field’s variation, we make use of sensitivity analysis. We will first describe the finite element model used for the submarine power cable. Submarine power cable’s physical dimensions and material properties used to build the finite element model are reported. With respect to the electric grid frequency (50 or 60 Hz) and submarine cable length (tens of kilometers), the electromagnetic problem is quasi-static. The electric and magnetic field don’t propagate, they are also decoupled. According to whether electric field variation or magnetic field variation only is taken into account, the capacitive phenomena or inductive ones can be studied. An electric field is induced in the metallic layers because of the main current flowing into the cable center conductor. By scanning a metallic layer contour called screen, we have noticed that a crack in this layer increases the electric field’s induced amplitude over the crack’s area. The crack is represented with a sector shaped geometry filled with air. This increase of the electric field was evaluated in terms of crack’s opening angle and depth. The sensitivity analysis is a probabilistic approach that evaluates the impact of input data variability on the output of a model. The evaluation is made by considering inputs as random variables and establishing each input data contribution on output variance. Thus, the less relevant inputs can be identified and the model simplified by setting these inputs to a mean value. Model parameters such as permittivity and resistivity, damage shape, location, material…etc. are varied to establish a hierarchy of the parameters that cause electric and magnetic field variation. Finally, the relevance of the electromagnetic analysis for detecting the faults and heterogeneities considered and the possible use of this analysis as a new sensing technic is discussed.
Memory Efficient Parallel 2-Opt for Large Scale Travelling Salesman Problems
To accelerate the solution of large scale travelling salesman problems (TSP), a parallel scheme based on partial 2-opt neighborhood checking is proposed and tested, which means not all 2-exchange possibilities are checked for one edge but only those of its neighborhood in two directions along the tour. The basic character of this parallel scheme is that we ensure multiple 2-opt exchanges can be checked and executed at the same time without interaction between two or more exchanges. To achieve this goal, an efficient two-direction linear network is proposed by using 'double links' to connect two cities instead of using traditional unidirectional one. In this two-direction linear network, every city has its two neighbor cities' indexes and can access to its neighborhood in 2 directions which allow the partial 2-opt checking for one edge can go in two directions. Once the optimization is found, the exchanges for each active city can be executed at the same time by only changing each node's neighbor indexes, and a final permutation solution is constructed also only by city's indexes one after another. Experiments show that this parallel scheme is meaningful for large scale TSP instance, converges quickly and can be regarded as a choice of an initial constructor for TSP.
Very Large Scale Integration (VLSI) Architecture of FIR Filter Implementation Using Retiming Technique
Recursive combination of algorithm based on Karatsuba multiplication is exploited to design generalized transpose and Parallel FIR Filter. Mid-range Karatsuba multiplication and carry save adder based on Karatsuba multiplication reduces time complexity for higher order multiplication implemented upto n-bit. As a result, we design modified N-tap Transpose and Parallel Symmetric FIR Filter Structure using Karatsuba algorithm. The mathematical formulation of the FFA Filter is derived. The proposed architecture involves significantly less area delay product (APD) then the existing block implementation. By adopting retiming technique, hardware cost is reduced further. The filter architecture is designed using 90nm technology library and is implemented using cadence EDA Tool. Synthesize result shows better for different word length and block size. The design achieves switching activity reduction and also in term of low power consumption by applying with and without retiming for different combination of the circuit. The proposed structure achieves more than a half of the power reduction by adopting with and without retiming techniques compared to earlier design structure. As a proof of the concept for block size 16 and filter length 64 for CKA method it achieves a 51% as well as 70% less power by applying retiming technique and CSA method it achieves a 57% as well as 77% less power by applying retiming technique compared to previously proposed design.
Mach-Zehnder Interferometer Based High Sensitive Water Salinity Sensor for Oceanographic Applications
A high sensitive Mach-Zehnder Interferometer (MZI) based fiber optic sensor for the measurement of sea water salinity has been demonstrated. A Carbon monoxide laser in the spectrum of 4.8 to 8.3 μm is used to excite the arms of MZI. It has been observed that wavelength shifts related to attenuation dips are highly sensitive to salinity of sea water. Using simple and robust schematic design, sensitivity of 0.01μm/‰ is achieved for salinity range of 31 to 37ppt at a constant temperature of 20oC. The all-optical MZI salinity sensor indicated here is easy to fabricate, low cost, highly sensitive and finds application mainly in the field of oceanography.
Transmit Power Optimization for Cooperative Beamforming in Reverse-Link MIMO Ad-Hoc Networks
In the Ad-hoc network, the great interests regarding MIMO scheme leads to their combination, which is also utilized into its applicable network. We manage the field of the problem into Reverse-link MIMO Ad-hoc Network (RMAN) and propose the methodology to maximize the data rate with its power consumption using Node-Cooperative beamforming technique. Based on the result of mathematical optimization formulation, we design the algorithm to construct optimal orthogonal weight vector according to channel feedback and control its transmission power according to QoS-pricing value level. In simulation results, we show the validity of the proposed mathematical optimization result and algorithm which mean that the sum-rate of each link is converged into some point.
Product Design and Development of Wearable Assistant Device
The world is gradually becoming an aging society, and with the lack of laboring forces, this phenomenon is affecting the nation’s economy growth. Although nursing centers are booming in recent years, the lack of medical resources are yet to be resolved, thus creating an innovative wearable medical device could be a vital solution. This research is focused on the design and development of a wearable device which obtains a more precise heart failure measurement than products on the market. The method used by the device is based on the sensor fusion and big data algorithm. From the test result, the modified structure of wearable device can significantly decrease the MA (Motion Artifact) and provide users a more cozy and accurate physical monitor experience.
Detecting and Secluding Route Modifiers by Neural Network Approach in Wireless Sensor Networks
In real world scenario, the viability of the sensor networks has proved by standardizing the technologies. Wireless sensor networks are vulnerable to both electronic and physical security breaches, because of their deployment in remote, distributed, inaccessible locations. The compromised sensor nodes send malicious data to the base station, thus the total network effectiveness will possibly be compromised. To detect and seclude the Route modifiers, a neural network based Pattern Learning predictor (PLP) is proposed. This algorithm senses data at any node on present and previous patterns obtained from the en-route nodes. The eminence of any node is upgraded by their predicted and reported patterns. This paper propounds a solution not only to detect the route modifiers and also to seclude the malevolent nodes from the network. The Simulation result proves the effective performance of the network by the proposed methodology in terms of energy level, routing and various network conditions.
Effects of Incident Angle and Distance on Visible Light Communication
Recently, IoT (Internet of Things) technology is becoming an increasingly growing topic of various researches. It has evolved from the convergence of wireless communication technologies, including VLC (Visible Light Communication). For this reason, VLC has been actively researched along with advantages of LED in their cost and widespread availability. There has been a variety of their applications that affected by characteristics of optical gains. Most of their works assumed that transmitter, especially LED, is placed in parallel to a receiver. However, this assumption is not valid for real-world applications where the receivers should be consistently movable in uncontrolled ways. It is necessary to analyze the case when transmitter is not perfectly parallel to receiver. In this paper, we conducted simulations of optical gain depending on incident angle and distance based on mathematical analysis. Then, we identified patterns of optical gains by several tilt angles in a receiver. After the simulation, we also compared them to real optical gains for experiments in various cases. These results can be used as an index when determining the error range of actual specification in many application using VLC.
Detection of Image Blur and Its Restoration for Image Enhancement
Image restoration in the process of communication is one of the emerging fields in the image processing. The motion analysis processing is the simplest case to detect motion in an image. Applications of motion analysis widely spread in many areas such as surveillance, remote sensing, film industry, navigation of autonomous vehicles, etc. The scene may contain multiple moving objects, by using motion analysis techniques the blur caused by the movement of the objects can be enhanced by filling-in occluded regions and reconstruction of transparent objects, and it also removes the motion blurring. This paper presents the design and comparison of various motion detection and enhancement filters. Median filter, Linear image deconvolution, Inverse filter, Pseudoinverse filter, Wiener filter, Lucy Richardson filter and Blind deconvolution filters are used to remove the blur. In this work, we have considered different types and different amount of blur for the analysis. Mean Square Error (MSE) and Peak Signal to Noise Ration (PSNR) are used to evaluate the performance of the filters. The designed system has been implemented in Matlab software and tested for synthetic and real-time images.
Design and Implementation of Image Super-Resolution for Myocardial Image
Super-resolution is the technique of intelligently upscaling images, avoiding artifacts or blurring, and deals with the recovery of a high-resolution image from one or more low-resolution images. Single-image super-resolution is a process of obtaining a high-resolution image from a set of low-resolution observations by signal processing. While super-resolution has been demonstrated to improve image quality in scaled down images in the image domain, its effects on the Fourier-based technique remains unknown. Super-resolution substantially improved the spatial resolution of the patient LGE images by sharpening the edges of the heart and the scar. This paper aims at investigating the effects of single image super-resolution on Fourier-based and image based methods of scale-up. In this paper, first, generate a training phase of the low-resolution image and high-resolution image to obtain dictionary. In the test phase, first, generate a patch and then difference of high-resolution image and interpolation image from the low-resolution image. Next simulation of the image is obtained by applying convolution method to the dictionary creation image and patch extracted the image. Finally, super-resolution image is obtained by combining the fused image and difference of high-resolution and interpolated image. Super-resolution reduces image errors and improves the image quality.
Design and Performance Analysis of Advanced B-Spline Algorithm for Image Resolution Enhancement
An approach to super-resolve the low-resolution (LR) image is presented in this paper which is very useful in multimedia communication, medical image enhancement and satellite image enhancement to have a clear view of the information in the image. The proposed Advanced B-Spline method generates a high-resolution (HR) image from single LR image and tries to retain the higher frequency components such as edges in the image. This method uses B-Spline technique and Crispening. This work is evaluated qualitatively and quantitatively using Mean Square Error (MSE) and Peak Signal to Noise Ratio (PSNR). The method is also suitable for real-time applications. Different combinations of decimation and super-resolution algorithms in the presence of different noise and noise factors are tested.
Symbol Synchronization and Resource Reuse Schemes for Layered Video Multicast Service in Long Term Evolution Networks
LTE (Long Term Evolution) employs the eMBMS (evolved Multimedia Broadcast/Multicast Service) protocol to deliver video streams to a multicast group of users. However, it requires all multicast members to receive a video stream in the same transmission rate, which would degrade the overall service quality when some users encounter bad channel conditions. To overcome this problem, this paper provides two efficient resource allocation schemes in such LTE network: The symbol synchronization (S2) scheme assumes that the macro and pico eNodeBs use the same frequency channel to deliver the video stream to all users. It then adopts a multicast transmission index to guarantee the fairness among users. On the other hand, the resource reuse (R2) scheme allows eNodeBs to transmit data on different frequency channels. Then, by introducing the concept of frequency reuse, it can further improve the overall service quality. Extensive simulation results show that the S2 and R2 schemes can respectively improve around 50% of fairness and 14% of video quality as compared with the common maximum throughput method.
A Reconfigurable Microstrip Patch Antenna with Polyphase Filter for Polarization Diversity and Cross-Polarization Filtering Operation
A Reconfigurable Microstrip Patch Antenna with Polyphase Filter for Polarization Diversity and Cross Polarization Filtering Operation is presented in this letter. In our approach, a Polyphase Filter is used to obtain the four 90° phase shift outputs to feed a square Microstrip Patch Antenna. The antenna can be switched between 4 states of polarization in transmission as well as in receiving mode. Switches are interconnected with the PPF network to produce Left-Hand Circular Polarization, Right-Hand Circular Polarization, Horizontal Linear Polarization and Vertical Linear Polarization. Additional advantage of using PPF is its filtering capability for cross polarization filtering in RHCP and LHCP operation. The theoretical and simulated results demonstrated that PPF is a good candidate to drive MPA to accomplish polarization diversity and cross polarization filtering operation.