Search

Developments in defect descriptors and computer vision-based algorithms for automatic optical inspection (AOI) allows for further development in image-based measurements. Defect classification is a vital part of an optical-imaging-based surface quality measuring instrument. The high-speed production rhythm of hot continuous rolling requires an ultra-rapid response to every component as well as algorithms in AOI instrument. In this paper, a simple, fast, yet robust texture descriptor, namely selectively dominant local binary patterns (SDLBPs), is proposed for defect classification. First, an intelligent searching algorithm with a quantitative thresholding mechanism is built to excavate the dominant non-uniform patterns (DNUPs). Second, two convertible schemes of pattern code mapping are developed for binary encoding of all uniform patterns and DNUPs. Third, feature extraction is carried out under SDLBP framework. Finally, an adaptive region weighting method is built for further strengthening the original nearest neighbor classifier in the feature matching stage. The extensive experiments carried out on an open texture database (Outex) and an actual surface defect database (Dragon) indicates that our proposed SDLBP yields promising performance on both classification accuracy and time efficiency.

In this paper a step-down ZVS power converter with a self-driven synchronous rectifier (SDSR) for a low-voltage high-current applications is proposed. A transformer leakage inductance, a resonant capacitor and a diode make up the active resonant network. To improve the performance of the converter, a SDSR with a center-tapped transformer is used at the secondary side of the converter. Consequently, due to transformer leakage inductance in secondary side, the output section requires no additional inductor, leading to a major size reduction of the circuit. For verification purposes, a laboratory prototype of the proposed converter is manufactured. Experimental results are presented for waveforms to validate the theoretical outcomes. Additionally, to substantiate the design of the proposed converter, a laboratory prototype is manufactured.

In this work, the design and simulations of a single, 1×4 rectangular patch array antenna on a Silicon nitride (Si 3 N 4 ) substrate operating at millimetre-wave (mm-wave) ISM (The Industrial, Scientific, and Medical) frequency band (57 - 64 (GHz)) are assessed through the simulations. The antenna is designed to be compatible with photonic integrated circuits (PIC) wireless Internet of Things (IoT) front-ends, for a bandwidth requirement of an approximate of 5 GHz, and gain range from 12 - 15 dBi enabling ranges of 5 - 10 meters. These small-sized, high gain antennas can easily be integrated into Si 3 N 4 PIC devices. In this work, we started with a single patch and expanded to an array where the Wilkinson four-way power divider network is used. The designed antennas are optimized to achieve 5 GHz of bandwidth and mainly 12 - 15 dBi of gain, meeting the use case requirements. The resulting antenna is benchmarked against other of the same type, and purpose showing similar performance and reduced size.

A 2-point Haar transform (HT) building block (BB) in an indium phosphide (InP) integrated platform is proposed. The developed BB consists of a $2\times 2$ multimode interference (MMI) with two delay lines phase shifters to attain the expect operation from the 2-point HT BB. The simulation and experimental results of the MMI coupler output access waveguides are presented and discussed. A coupling ratio of 88:12 was achieved in the developed BB.

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

In this paper, we propose a distance based energy efficient multiple relay selection algorithm for cooperative virtual Multiple-Input-Multiple-Output (MIMO). The fundamentals of this method is to forward the source signal using the node which minimizes the end-to-end total path distance, such that the total energy cost per bit is reduced at the relay and at the source. An energy efficient multiple relay selection algorithm is proposed to minimize the energy cost per bit while achieving a target system performance in terms of BER at the destination. The core of the proposed relay selection method is selecting the node set that minimize the overall path lengths. We present the impact of the relay location and the constellation size for different MIMO configuration, and prove numerically that minimizing the sum of all path link length leads to lower energy consumption under the same performance requirement for MIMO, Multiple-Input-Single-Output (MISO) and Single-Input-Multiple-Output (SIMO) configuration. We compare the performance of MIMO, SIMO and MISO in terms of energy consumption and we present the results in terms of energy cost per bit against transmission distance. The results presented show that the proposed algorithm outperforms non optimized MIMO and traditional virtual MIMO communication in terms of energy consumption per bit for fixed rate and variable rate systems.

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

The usage of the Android Operating System (OS) has surpassed all other operating systems and as a result, it has become the primary target of attackers. Many attacks can be geared towards Android phones mainly using application installation. These third-party applications first seek permission from the user before installation. Some of the permissions can be elusive evading the users’ attention. With the type of harm that can be done which include illegal extraction and transfer of the users’ data, spying on the users and so on there is a need to have a heuristic approach in the detection of malware. In this research work, some classification algorithms were tested to determine the best performing algorithm when it comes to the detection of android malware detection. An android application dataset was obtained from figshare and used in the Waikato Environment for Knowledge Analysis (WEKA) for training and testing, it was measured under accuracy, false-positive rate, precision, recall, f-measure, Receiver Operating Curve (ROC) and Root Mean Square Error (RMSE). It was discovered that multi-layer perceptron performs best with an accuracy of 99.4%.

Cognitive radio networks (CRNs) are found to be, without difficulty wide-open to external malicious threats. Secure communication is an important prerequisite for forthcoming fifth-generation (5G) systems, and CRs are not exempt. A framework for developing the accomplishable benefits of physical layer security (PLS) in an amplify-and-forward cooperative spectrum sensing (AF-CSS) in a cognitive radio network (CRN) using a stochastic geometry is proposed. In the CRN the spectrum sensing data from secondary users (SU) are collected by a fusion center (FC) with the assistance of access points (AP) as cognitive relays, and when malicious eavesdropping SU are listening. In this paper we focus on the secure transmission of active APs relaying their spectrum sensing data to the FC. Closed expressions for the average secrecy rate are presented. Analytical formulations and results substantiate our analysis and demonstrate that multiple antennas at the APs is capable of improving the security of an AF-CSSCRN. The obtained numerical results also show that increasing the number of FCs, leads to an increase in the secrecy rate between the AP and its correlated FC.

Energy audit and reliability assessment of distribution systems are important to keep track of power system's performance. This will in turn help to minimize power interruptions to customers, boost industrialization, research, and economic development in any nation. In this paper, we present the reliability assessment of power distribution in Afe Babalola University, Ado-Ekiti, Nigeria which is a private University with an estimated population of about 10,500 and having a peak power demand of 2MW. A critical assessment of the power distribution system was carried out with data obtained from the campus's central Substation, taking into account various reliability indices. Furthermore, the load consumption of each substation was obtained from the period of January, 2017 to December, 2017. The results obtained show that the University attained a power availability (ASAI) of 0.99984 because of the presence of strategically placed distributed generators (DGs). The reliability assessment revealed SAIDI as 1.4347 hours /customer year, CAIDI as 0.6620 hours/customer interruption, ASUI as 0.00016, and SAIFI as 2.16712 failures/ customer year. Furthermore, the study revealed that the university spends more on diesel generators than on the electricity supplied from Benin Electricity Distribution Company (BEDC). The aforementioned reliability results reveal that power distribution in Afe Babalola University is very reliable, efficient and stable.

In this paper, a framework for capitalizing on the potential benefits of physical layer security in an amplify-and-forward cooperative spectrum sensing (AF-CSS) in a cognitive radio network (CRN) using a stochastic geometry is proposed. In the CRN network the sensing data from secondary users (SUs) are collected by a fusion center (FC) with the help of access points (AP) as relays, and when malicious eavesdropping secondary users (SUs) are listening. We focus on the secure transmission of active SUs transmitting their sensing data to the AP. Closed expressions for the average secrecy rate are presented. Numerical results corroborate our analysis and show that multiple antennas at the APs can enhance the security of the AF-CSS-CRN. The obtained numerical results show that average secrecy rate between the AP and its correlated FC decreases when the number of AP is increased. Nevertheless, we find that an increase in the number of AP initially increases the overall average secrecy rate, with a perilous value at which the overall average secrecy rate then decreases. While increasing the number of active SUs, there is a decrease in the secrecy rate between the sensor and its correlated AP.

Cognitive radio is a promising technology that answers the spectrum scarcity problem arising from the proliferation of wireless networks and mobile services. In this paper, spectrum sensing of digital video broadcasting-second generation terrestrial (DVB-T2) signals in AWGN, WRAN and COST207 multipath fading environment are considered. ED is known to achieve an increased performance among low computational complexity detectors, but it is susceptible to noise uncertainty. Taking into consideration the edge pilot and scattered pilot periodicity in DVB-T2 signals, a low computational noise power estimator is proposed. Analytical forms for the detector are derived. Simulation results show that with the noise power estimator, ED significantly outperforms the pilot correlation-based detectors. Simulation also show that the proposed scheme enables ED to obtain increased detection performance in multi-path fading environments. Moreover, based on this algorithm a practical sensing scheme for cognitive radio networks is proposed.

In this paper a novel simple all digital frequency locking circuit design is presented together with its performance results. The proposed method can be used to lock DDSs to a reference clock such as a data clock. It allows for efficient fully multi-rate modem design (with a resolution bound by the DDS) within a low cost FPGA. In fact, using the new scheme the baseband modem can be completely constructed within the FPGA without external complicated and expensive VCOs and their associated locking loops.

For a multiuser multiple-input-multiple-output (MIMO) overlay cognitive radio (CR) network, a spacetime opportunistic interference alignment (ST-OIA) technique has been proposed that allows spectrum sharing between primary users (PU) and secondary users (SU) while ensuring zero interference to the PU. The CR system consists of one primary user (PU) and K secondary users (SU) where local channel state information is available at both the transmitters and receivers of SUs. The PU uses space-time water-filling (ST-WF) algorithm to optimize the PUs transmission and in the process, frees up unused eigenmodes that can be exploited by the SU. Because ST-WF achieves higher capacity per antenna than other methods, at low to moderate SNR regimes, it makes it ideal for implementation in CR networks. The SUs align their transmitted signals in such a way their interference impairs only the PUs unused eigenmodes. For this solution with multiple SUs exploiting the benefits of cooperative spectrum sensing to work, there are three separate conditions which must be met. For single user MIMO PU and SU link, the first condition requires there should be zero interference at the PU receiver and secondly, there should be zero interference to both the PU and SU receivers. The third condition caters for the multiple SU scenario which requires limited cooperation between the PU receiver and the multiple SUs to ensure interference from multiple SUs are aligned along unused eigenmodes. Finally, the SU system is assumed to be a time division duplex (TDD) system such that principle of Reciprocity is employed towards optimizing the SUs transmission rates.

This paper focuses on the quantization of soft decision based cooperative spectrum sensing (CSS). The soft data fusion CSS schemes in previous research works provide considerable enhancement in the probability of detection, but at the expense of increased bandwidth required for transmitting the sensing measurements to the Fusion Center (FC). In this paper, Maximum likelihood Estimation (MLE) statistics are quantized and sent to the FC as an alternative of the quantized decision statistics of Log-Likelihood Ratios (LLRs) which assume that the distribution of the received primary user (PU) signal is known. Uniform and optimal entropy quantization's are proposed to reduce the reporting channel overheads and a low complex overhead is proposed which helps speed up the PU signal sensing process. This can be significant in high data rate applications. Simulation results illustrate that the scheme can obtain a high detection rate and a reduction in the reporting channel bandwidth.

Cognitive radio has become an effective technology to solve the underutilisation problem of the spectrum. In recent times, spectrum sensing has been intensively studied as a key technology in realising the cognitive radio. In this paper, we consider an amplify-and-forward relay-based cooperative spectrum sensing using a double threshold energy detector. Each secondary cognitive user takes a local decision on spectrum occupancy based on two energy detection thresholds. If it detects the value out of both thresholds, it makes a decision first, amplifies and forwards the local result to the fusion center. If the detected value falls between the both thresholds, it amplifies and forwards this detected value to the fusion center. Finally, energy fusion and decision fusion are conducted at the fusion center to determine the primary user status. Cooperative probability of detection, probability of missed detection and probability of false alarm are derived theoretically with and without direct communication between the primary user and fusion centre. Simulation results show that the proposed method achieves an improvement in probability of detection.

Cooperative Spectrum Sensing has been investigated in Rayleigh-fading environments over non-ideal reporting channels, where the simulation results have shown that its performance is limited by the probability of reporting errors. This paper proposes a transmit diversity scheme using Differential Space-Time coding where channel state information is not required. By regarding multiple pairs of Cognitive Radios as virtual antenna arrays in multiple clusters, Differential space-time coding is applied for the purpose of decision reporting over Rayleigh channels. Hard combination schemes are employed at the fusion center due to their minimal bandwidth requirements. Simulations results show that this method also achieves full transmit diversity, albeit with slight performance degradation in terms of power. The results also show improvements in sensing performance when compared to conventional cooperative spectrum sensing over non-ideal reporting channels.

Agent-oriented patterns have been considered potentially useful for improving communication and comprehension of the concepts they describe and for bridging the gap between conceptual modeling and implementation. A pattern needs to be appropriately described for it to be an effective tool of experience sharing. However, many existing approaches to agent patterns lack features that we consider important to pattern descriptions. In this paper, we present a template that we believe improves on current ways of describing agent patterns. We also describe the BDI agent architectural level pattern using our template.

Software patterns have potential to enhance the comprehension, application and communication of agent oriented software concepts. To realize this potential, agent oriented patterns should be appropriately described with the aid of good pattern templates. However, many of the existing descriptions of agent patterns lack certain features that are critical to the description of agent patterns. In this paper, we present a design for agent oriented pattern templates. We present two templates built according to our design that we believe improve on the description of agent patterns. The InteRRaP agent architectural pattern and Contract Net agent interaction pattern are presented using these templates.