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Computers
Volume 9
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Computers, Volume 9, Issue 3 (September 2020) – 22 articles

Cover Story (view full-size image): This article presents an experimental setup that passively collects DNS data from a network and then uses permissioned distributed ledger technology to store the data in an immutable ledger, thus providing a full historical overview of all records. The passive DNS data collection process creates a database containing various DNS data elements, some of which are personal and need to be protected to preserve the privacy of end-users. The proposed solution supports private queries for storing and retrieving data from the blockchain ledger, allowing use of the passive DNS database for further analysis, e.g., for the identification of malicious domain names. View this paper
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28 pages, 5276 KiB  
Article
Fog Computing for Realizing Smart Neighborhoods in Smart Grids
by Rituka Jaiswal, Reggie Davidrajuh and Chunming Rong
Computers 2020, 9(3), 76; https://doi.org/10.3390/computers9030076 - 21 Sep 2020
Cited by 15 | Viewed by 5367
Abstract
Cloud Computing provides on-demand computing services like software, networking, storage, analytics, and intelligence over the Internet (“the cloud”). But it is facing challenges because of the explosion of the Internet of Things (IoT) devices and the volume, variety, veracity and velocity of the [...] Read more.
Cloud Computing provides on-demand computing services like software, networking, storage, analytics, and intelligence over the Internet (“the cloud”). But it is facing challenges because of the explosion of the Internet of Things (IoT) devices and the volume, variety, veracity and velocity of the data generated by these devices. There is a need for ultra-low latency, reliable service along with security and privacy. Fog Computing is a promising solution to overcome these challenges. The originality, scope and novelty of this paper is the definition and formulation of the problem of smart neighborhoods in context of smart grids. This is achieved through an extensive literature study, firstly on Fog Computing and its foundation technologies, its applications and the literature review of Fog Computing research in various application domains. Thereafter, we introduce smart grid and community MicroGrid concepts and, their challenges to give the in depth background of the problem and hence, formalize the problem. The smart grid, which ensures reliable, secure, and cost-effective power supply to the smart neighborhoods, effectively needs Fog Computing architecture to achieve its purpose. This paper also identifies, without rigorous analysis, potential solutions to address the problem of smart neighborhoods. The challenges in the integration of Fog Computing and smart grids are also discussed. Full article
(This article belongs to the Special Issue Feature Paper in Computers)
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<p>Fog Computing high-level architecture and application in various domains.</p> Full article ">Figure 2
<p>Comparison of Fog Computing and its related computing paradigms.</p> Full article ">Figure 3
<p>Smart Grid flow.</p> Full article ">Figure 4
<p>Advanced metering infrastructure(AMI).</p> Full article ">Figure 5
<p>V2G and RES integration in smart grids.</p> Full article ">Figure 6
<p>Fog Computing architecture for smart neighborhoods.</p> Full article ">Figure 7
<p>Solution technologies to Smart community neighborhood realization.</p> Full article ">Figure 8
<p>Solving smart community neighborhood challenges with Artificial Intelligence technique.</p> Full article ">
15 pages, 2283 KiB  
Article
Unmanned Aerial Vehicle Control through Domain-Based Automatic Speech Recognition
by Ruben Contreras, Angel Ayala and Francisco Cruz
Computers 2020, 9(3), 75; https://doi.org/10.3390/computers9030075 - 19 Sep 2020
Cited by 16 | Viewed by 6083
Abstract
Currently, unmanned aerial vehicles, such as drones, are becoming a part of our lives and extend to many areas of society, including the industrialized world. A common alternative for controlling the movements and actions of the drone is through unwired tactile interfaces, for [...] Read more.
Currently, unmanned aerial vehicles, such as drones, are becoming a part of our lives and extend to many areas of society, including the industrialized world. A common alternative for controlling the movements and actions of the drone is through unwired tactile interfaces, for which different remote control devices are used. However, control through such devices is not a natural, human-like communication interface, which sometimes is difficult to master for some users. In this research, we experimented with a domain-based speech recognition architecture to effectively control an unmanned aerial vehicle such as a drone. The drone control was performed in a more natural, human-like way to communicate the instructions. Moreover, we implemented an algorithm for command interpretation using both Spanish and English languages, as well as to control the movements of the drone in a simulated domestic environment. We conducted experiments involving participants giving voice commands to the drone in both languages in order to compare the effectiveness of each, considering the mother tongue of the participants in the experiment. Additionally, different levels of distortion were applied to the voice commands to test the proposed approach when it encountered noisy input signals. The results obtained showed that the unmanned aerial vehicle was capable of interpreting user voice instructions. Speech-to-action recognition improved for both languages with phoneme matching in comparison to only using the cloud-based algorithm without domain-based instructions. Using raw audio inputs, the cloud-based approach achieves 74.81% and 97.04% accuracy for English and Spanish instructions, respectively. However, with our phoneme matching approach the results are improved, yielding 93.33% accuracy for English and 100.00% accuracy for Spanish. Full article
(This article belongs to the Special Issue Feature Paper in Computers)
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<p>Example of quadrotor drones. The unmanned aerial vehicles are shown in both real-world and simulated environments. (<b>a</b>) DJI Phantom radio controlled quadrotor operating in a real environment; (<b>b</b>) Simulated quadrotor drone in V-REP used in the proposed domestic scenario.</p> Full article ">Figure 2
<p>The proposed architecture for UAV control through speech. In this representation, a person speaks the instructions in a microphone, and these are processed by our algorithm. The instruction is then classified using the domain-based dictionary and executes for the UAV.</p> Full article ">Figure 3
<p>The simulated domestic environment in V-REP with a quadrotor and furniture used daily, such as sofas, chairs, a table, a shelf, and a plant.</p> Full article ">Figure 4
<p>Average recognition accuracy for each action class in Spanish and English languages with different levels of noise in the input signal. Without using phoneme matching, the text received from the cloud-based service was directly transferred to the scenario. This implementation showed a considerable difference between languages due to the user’s native language. Using phoneme matching, the text received from the cloud-based service was compared to the instructions within the domain-based dictionary. The use of phoneme matching demonstrated an improvement in speech-to-action recognition for both languages, decreasing the difference of accuracy between them. (<b>a</b>) Raw input, no phoneme matching; (<b>b</b>) Noise 5%, no phoneme matching; (<b>c</b>) Noise 15%, no phoneme matching; (<b>d</b>) Raw input, with phoneme matching; (<b>e</b>) Noise 5%, with phoneme matching; (<b>f</b>) Noise 15%, with phoneme matching.</p> Full article ">Figure 5
<p>Audio recognition accuracy for all the experimental setups using both languages. NPM and WPM stand for no phoneme matching and with phoneme matching, respectively, and the percentage beside the approach in x-axis represents the noise value of each setup. Continuous and segmented lines represent the median and mean values in each box. The use of phoneme matching significantly improved the speech-to-action recognition even in the presence of noisy inputs. (<b>a</b>) Recognition accuracy using English instructions; (<b>b</b>) Recognition accuracy using Spanish instructions.</p> Full article ">Figure 6
<p>Predicted and true class distribution for each experimental setup using English instructions. Phoneme matching improved the overall results obtaining fewer misclassifications for all the action classes. Although a noisy input impoverished the action class classification in both approaches, the use of phoneme matching allowed for better recognition accuracy for all levels of noise.</p> Full article ">Figure 7
<p>Predicted and true class distribution for each experimental setup using Spanish instructions. When Spanish language was used, fewer errors in action classification occurred in comparison to English instructions. Nevertheless, the phoneme matching still allowed better recognition accuracy for all levels of noise in comparison to the approach not using it.</p> Full article ">
17 pages, 1356 KiB  
Article
Toward a Sustainable Cybersecurity Ecosystem
by Shahrin Sadik, Mohiuddin Ahmed, Leslie F. Sikos and A. K. M. Najmul Islam
Computers 2020, 9(3), 74; https://doi.org/10.3390/computers9030074 - 17 Sep 2020
Cited by 45 | Viewed by 10885
Abstract
Cybersecurity issues constitute a key concern of today’s technology-based economies. Cybersecurity has become a core need for providing a sustainable and safe society to online users in cyberspace. Considering the rapid increase of technological implementations, it has turned into a global necessity in [...] Read more.
Cybersecurity issues constitute a key concern of today’s technology-based economies. Cybersecurity has become a core need for providing a sustainable and safe society to online users in cyberspace. Considering the rapid increase of technological implementations, it has turned into a global necessity in the attempt to adapt security countermeasures, whether direct or indirect, and prevent systems from cyberthreats. Identifying, characterizing, and classifying such threats and their sources is required for a sustainable cyber-ecosystem. This paper focuses on the cybersecurity of smart grids and the emerging trends such as using blockchain in the Internet of Things (IoT). The cybersecurity of emerging technologies such as smart cities is also discussed. In addition, associated solutions based on artificial intelligence and machine learning frameworks to prevent cyber-risks are also discussed. Our review will serve as a reference for policy-makers from the industry, government, and the cybersecurity research community. Full article
(This article belongs to the Special Issue Feature Paper in Computers)
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<p>A simple hierarchy of cyber-risks (adapted from [<a href="#B22-computers-09-00074" class="html-bibr">22</a>]).</p> Full article ">Figure 2
<p>Cybersecurity lifecycle (adapted from [<a href="#B21-computers-09-00074" class="html-bibr">21</a>]).</p> Full article ">Figure 3
<p>Continuous improvement of cybersecurity (adapted from [<a href="#B21-computers-09-00074" class="html-bibr">21</a>]).</p> Full article ">
17 pages, 6270 KiB  
Article
The Use of Geolocation to Manage Passenger Mobility between Airports and Cities
by Antonio Sarasa-Cabezuelo
Computers 2020, 9(3), 73; https://doi.org/10.3390/computers9030073 - 11 Sep 2020
Cited by 3 | Viewed by 4033
Abstract
A general problem in large cities is mobility. Every day, there are incidents (accidents, construction, or meteorological events) that increase the duration of the journeys in a city and exert negative effects on the lives of citizens. A particular case of this situation [...] Read more.
A general problem in large cities is mobility. Every day, there are incidents (accidents, construction, or meteorological events) that increase the duration of the journeys in a city and exert negative effects on the lives of citizens. A particular case of this situation is communications with airports. Shuttles are a type of private transport service that operates in airports. The number of passengers carried by shuttles is small. Moreover, shuttles transport passengers to their final destinations and their prices are more competitive than those other private services. However, shuttle services have a limitation with respect to their routes due to the many different destinations of passengers. For this reason, it is important to be able to calculate the best route to optimize the journey. This work presents an Android application that implements a value-added service to plan the route of a shuttle and manage its service (passengers, journeys, routes, etc.). This application combines information from different sources, such as geolocation information from the shuttle driver’s mobile phone, information on the passengers, and results obtained from the service offered by MapBox to calculate the optimized route between several destinations. Full article
(This article belongs to the Special Issue Web of Things for Humans (WoT4H))
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<p>Structure of the solution.</p> Full article ">Figure 2
<p>Architecture of the solution.</p> Full article ">Figure 3
<p>Data model.</p> Full article ">Figure 4
<p>(<b>a</b>) Administrator interface, (<b>b</b>) selection origin, and (<b>c</b>) origin interface.</p> Full article ">Figure 5
<p>(<b>a</b>) Administrator’s menu and (<b>b</b>) list of origins registered.</p> Full article ">Figure 6
<p>(<b>a</b>) Main driver interface, (<b>b</b>) interface of route created, and (<b>c</b>) route.</p> Full article ">Figure 7
<p>(<b>a</b>) Menu and (<b>b</b>) list of the available routes.</p> Full article ">Figure 8
<p>(<b>a</b>) Main passenger interface, (<b>b</b>) list of bus routes, and (<b>c</b>) details of the route.</p> Full article ">Figure 9
<p>(<b>a</b>) Menu, (<b>b</b>) list of the available routes, and (<b>c</b>) details of the route.</p> Full article ">Figure 10
<p>(<b>a</b>) Register, (<b>b</b>) register, and (<b>c</b>) login.</p> Full article ">Figure 11
<p>(<b>a</b>) Utility of the application, (<b>b</b>) Ease of use of the application, (<b>c</b>) Design of the application, and (<b>d</b>) Global assessment.</p> Full article ">
9 pages, 636 KiB  
Article
Fusion Convolutional Neural Network for Cross-Subject EEG Motor Imagery Classification
by Karel Roots, Yar Muhammad and Naveed Muhammad
Computers 2020, 9(3), 72; https://doi.org/10.3390/computers9030072 - 5 Sep 2020
Cited by 62 | Viewed by 8231
Abstract
Brain–computer interfaces (BCIs) can help people with limited motor abilities to interact with their environment without external assistance. A major challenge in electroencephalogram (EEG)-based BCI development and research is the cross-subject classification of motor imagery data. Due to the highly individualized nature of [...] Read more.
Brain–computer interfaces (BCIs) can help people with limited motor abilities to interact with their environment without external assistance. A major challenge in electroencephalogram (EEG)-based BCI development and research is the cross-subject classification of motor imagery data. Due to the highly individualized nature of EEG signals, it has been difficult to develop a cross-subject classification method that achieves sufficiently high accuracy when predicting the subject’s intention. In this study, we propose a multi-branch 2D convolutional neural network (CNN) that utilizes different hyperparameter values for each branch and is more flexible to data from different subjects. Our model, EEGNet Fusion, achieves 84.1% and 83.8% accuracy when tested on the 103-subject eegmmidb dataset for executed and imagined motor actions, respectively. The model achieved statistically significantly higher results compared with three state-of-the-art CNN classifiers: EEGNet, ShallowConvNet, and DeepConvNet. However, the computational cost of the proposed model is up to four times higher than the model with the lowest computational cost used for comparison. Full article
(This article belongs to the Special Issue Machine Learning for EEG Signal Processing)
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<p>The proposed three-branch fusion convolutional neural network (CNN) architecture, termed EEGNet Fusion.</p> Full article ">Figure 2
<p>The architecture of the original EEGNet model.</p> Full article ">
19 pages, 3995 KiB  
Article
An Evolutionary Approach for the Hierarchical Scheduling of Safety- and Security-Critical Multicore Architectures
by Brandon Woolley, Susan Mengel and Atila Ertas
Computers 2020, 9(3), 71; https://doi.org/10.3390/computers9030071 - 3 Sep 2020
Cited by 6 | Viewed by 3208
Abstract
The aerospace and defense industry is facing an end-of-life production issue with legacy embedded uniprocessor systems. Most, if not all, embedded processor manufacturers have already moved towards system-on-a-chip multicore architectures. Current scheduling arrangements do not consider schedules related to safety and security. The [...] Read more.
The aerospace and defense industry is facing an end-of-life production issue with legacy embedded uniprocessor systems. Most, if not all, embedded processor manufacturers have already moved towards system-on-a-chip multicore architectures. Current scheduling arrangements do not consider schedules related to safety and security. The methods are also inefficient because they arbitrarily assign larger-than-necessary windows of execution. This research creates a hierarchical scheduling framework as a model for real-time multicore systems to integrate the scheduling for safe and secure systems. This provides a more efficient approach which automates the migration of embedded systems’ real-time software tasks to multicore architectures. A novel genetic algorithm with a unique objective function and encoding scheme was created and compared to classical bin-packing algorithms. The simulation results show the genetic algorithm had 1.8–2.5 times less error (a 56–71% difference), outperforming its counterparts in uniformity in utilization. This research provides an efficient, automated method for commercial, private and defense industries to use a genetic algorithm to create a feasible two-level hierarchical schedule for real-time embedded multicore systems that address safety and security constraints. Full article
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<p>Example multicore asymmetric multiprocessing (AMP) mode with guest operating system (OS) virtualization.</p> Full article ">Figure 2
<p>Schematic of the allocation of tasks to partitions to cores.</p> Full article ">Figure 3
<p>A logically combined two-level schedule.</p> Full article ">Figure 4
<p>The chromosomal encoding method.</p> Full article ">Figure 5
<p>The experimental platform and detailed configuration information.</p> Full article ">Figure 6
<p>Results for the period range 10–100. GA: genetic algorithm; BFD: best fit decreasing; FFD: first fit decreasing; FF: first fit; BF: best fit.</p> Full article ">Figure 7
<p>Results for the period range 10–200.</p> Full article ">Figure 8
<p>Results for the period range 10–500.</p> Full article ">Figure 9
<p>Results for the period range 10–1000.</p> Full article ">
20 pages, 7051 KiB  
Article
A P4-Enabled RINA Interior Router for Software-Defined Data Centers
by Carolina Fernández, Sergio Giménez, Eduard Grasa and Steve Bunch
Computers 2020, 9(3), 70; https://doi.org/10.3390/computers9030070 - 2 Sep 2020
Cited by 6 | Viewed by 5057
Abstract
The lack of high-performance RINA (Recursive InterNetwork Architecture) implementations to date makes it hard to experiment with RINA as an underlay networking fabric solution for different types of networks, and to assess RINA’s benefits in practice on scenarios with high traffic loads. High-performance [...] Read more.
The lack of high-performance RINA (Recursive InterNetwork Architecture) implementations to date makes it hard to experiment with RINA as an underlay networking fabric solution for different types of networks, and to assess RINA’s benefits in practice on scenarios with high traffic loads. High-performance router implementations typically require dedicated hardware support, such as FPGAs (Field Programmable Gate Arrays) or specialized ASICs (Application Specific Integrated Circuit). With the advance of hardware programmability in recent years, new possibilities unfold to prototype novel networking technologies. In particular, the use of the P4 programming language for programmable ASICs holds great promise for developing a RINA router. This paper details the design and part of the implementation of the first P4-based RINA interior router, which reuses the layer management components of the IRATI Linux-based RINA implementation and implements the data-transfer components using a P4 program. We also describe the configuration and testing of our initial deployment scenarios, using ancillary open-source tools such as the P4 reference test software switch (BMv2) or the P4Runtime API. Full article
(This article belongs to the Special Issue Post-IP Networks: Advances on RINA and other Alternative Network Architectures)
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<p>Summary of the development workflow of a P4 program (source ONF, Open Networking Foundation).</p> Full article ">Figure 2
<p>Example of the systems in datacenters (DC) and their connectivity.</p> Full article ">Figure 3
<p>Example design for the DIFs in a DC, showing VM (Virtual Machine) to VM connectivity. Small circles represent IPC Processes (IPCPs), while large circles represent application instances [<a href="#B15-computers-09-00070" class="html-bibr">15</a>].</p> Full article ">Figure 4
<p>Example design for the DIFs in multiple DCs, showing VM (Virtual Machine) to VM connectivity. Small circles represent IPC Processes (IPCPs), while large circles represent application instances.</p> Full article ">Figure 5
<p>RINA router use cases.</p> Full article ">Figure 6
<p>Functional split for the components of a RINA router implementation using P4.</p> Full article ">Figure 7
<p>Design of a RINA over Ethernet interior router pipeline, using the <span class="html-italic">v1model</span> architecture.</p> Full article ">Figure 8
<p>Data plane ingress processing logic.</p> Full article ">Figure 9
<p>P4 Runtime API Client setting up session with server.</p> Full article ">Figure 10
<p>P4 Runtime API Client setting up session with server.</p> Full article ">Figure 11
<p>Stratum implementation running on top of BMv2 (source: ONF, Open Networking Foundation).</p> Full article ">Figure 12
<p>Python code for P4Runtime-Shell session setup and packet monitoring.</p> Full article ">Figure 13
<p>Virtual environment with 2 hosts and 1 Stratum BMv2 software switch.</p> Full article ">Figure 14
<p>Configuration of the forwarding table entries using the P4 Runtime API from a Python program.</p> Full article ">Figure 15
<p>Local VM scenario. Throughput in Mbps vs. packet size in bytes.</p> Full article ">Figure 16
<p>Local VM scenario. Packet loss vs. inter-arrival time (IAT) for a packet size of 500 bytes.</p> Full article ">Figure 17
<p>AWS VM scenario. Throughput in Mbps vs. packet size in bytes.</p> Full article ">Figure 18
<p>AWS VM scenario. Packet loss vs. inter-arrival time (IAT) for a packet size of 500 bytes.</p> Full article ">Figure 19
<p>Adapting IRATI layer management modules to implement the router’s control plane.</p> Full article ">
15 pages, 901 KiB  
Article
An Oracle-Based On-Chain Privacy
by Yu-Jen Chen, Ja-Ling Wu, Yung-Chen Hsieh and Chih-Wen Hsueh
Computers 2020, 9(3), 69; https://doi.org/10.3390/computers9030069 - 29 Aug 2020
Cited by 4 | Viewed by 4582
Abstract
In this work, we demonstrate how the blockchain and the off-chain storage interact via Oracle-based mechanisms, which build an effective connection between a distributed database and real assets. For demonstration purposes, smart contracts were drawn up to deal with two different applications. Due [...] Read more.
In this work, we demonstrate how the blockchain and the off-chain storage interact via Oracle-based mechanisms, which build an effective connection between a distributed database and real assets. For demonstration purposes, smart contracts were drawn up to deal with two different applications. Due to the characteristics of the blockchain, we may still encounter severe privacy issues, since the data stored on the blockchain are exposed to the public. The proposed scheme provides a general solution for resolving the above-mentioned privacy issue; that is, we try to protect the on-chain privacy of the sensitive data by using homomorphic encryption techniques. Specifically, we constructed a secure comparison protocol that can check the correctness of a logic function directly in the encrypted domain. By using the proposed access control contract and the secure comparison protocol, one can carry out sensitive data-dependent smart contract operations without revealing the data themselves. Full article
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<p>A blockchain diagram of the proposed scheme, where an Ethereum Virtual Machine (EVM) is connecting with an Oracle.</p> Full article ">Figure 2
<p>The sketch map of the proposed application scenario 1.</p> Full article ">Figure 3
<p>The storage contract for supporting the proposed automation of a stock management system (AoSMS).</p> Full article ">Figure 4
<p>The sketch map of the proposed access control system (ACS) for protecting sensitive databases.</p> Full article ">Figure 5
<p>An illustrative example of an encrypted data-dependent access control mechanism. Note that the public key encrypts each employee’s salary, and R represents a random number that is selected by the employees they themselves.</p> Full article ">
22 pages, 2388 KiB  
Article
The Effect That Auditory Distractions Have on a Visual P300 Speller While Utilizing Low-Cost Off-the-Shelf Equipment
by Patrick Schembri, Maruisz Pelc and Jixin Ma
Computers 2020, 9(3), 68; https://doi.org/10.3390/computers9030068 - 27 Aug 2020
Cited by 3 | Viewed by 3519
Abstract
This paper investigates the effect that selected auditory distractions have on the signal of a visual P300 Speller in terms of accuracy, amplitude, latency, user preference, signal morphology, and overall signal quality. In addition, it ensues the development of a hierarchical taxonomy aimed [...] Read more.
This paper investigates the effect that selected auditory distractions have on the signal of a visual P300 Speller in terms of accuracy, amplitude, latency, user preference, signal morphology, and overall signal quality. In addition, it ensues the development of a hierarchical taxonomy aimed at categorizing distractions in the P300b domain and the effect thereof. This work is part of a larger electroencephalography based project and is based on the P300 speller brain–computer interface (oddball) paradigm and the xDAWN algorithm, with eight to ten healthy subjects, using a non-invasive brain–computer interface based on low-fidelity electroencephalographic (EEG) equipment. Our results suggest that the accuracy was best for the lab condition (LC) at 100%, followed by music at 90% (M90) at 98%, trailed by music at 30% (M30) and music at 60% (M60) equally at 96%, and shadowed by ambient noise (AN) at 92.5%, passive talking (PT) at 90%, and finally by active listening (AL) at 87.5%. The subjects’ preference prodigiously shows that the preferred condition was LC as originally expected, followed by M90, M60, AN, M30, AL, and PT. Statistical analysis between all independent variables shows that we accept our null hypothesis for both the amplitude and latency. This work includes data and comparisons from our previous papers. These additional results should give some insight into the practicability of the aforementioned P300 speller methodology and equipment to be used for real-world applications. Full article
(This article belongs to the Special Issue Selected Papers from the 11th Computer Science and Electronic Engineering Conference (CEEC 2019))
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<p>Development of a P300b hierarchical taxonomy for distractions, which is extensible.</p> Full article ">Figure 2
<p>OpenBCI Cyton board and Electro-Cap.</p> Full article ">Figure 3
<p>Cyton board (front and back) components.</p> Full article ">Figure 4
<p>(<b>a</b>) Requested symbol highlighted in blue at the beginning of the symbol run and (<b>b</b>) the predicted symbol highlighted in green.</p> Full article ">Figure 5
<p>Auditory distractions, session 1, amplitude, descriptive plot.</p> Full article ">Figure 6
<p>Auditory distractions, session 1, latency, descriptive plot.</p> Full article ">Figure 7
<p>Auditory distractions, session 2, amplitude, descriptive plot.</p> Full article ">Figure 8
<p>Auditory distractions, session 2, latency, descriptive Plot.</p> Full article ">Figure 9
<p>Auditory distractions, session 1, grand average for all eight subjects. The <span class="html-italic">x</span>-axis represents time (ms), while the <span class="html-italic">y</span>-axis represents the amplitude (μV).</p> Full article ">Figure 10
<p>Auditory distractions, session 2, grand average for all eight subjects. The <span class="html-italic">x</span>-axis represents the time (ms), while the <span class="html-italic">y</span>-axis represents the amplitude (μV).</p> Full article ">
21 pages, 4929 KiB  
Article
Experimental Study for Determining the Parameters Required for Detecting ECG and EEG Related Diseases during the Timed-Up and Go Test
by Vasco Ponciano, Ivan Miguel Pires, Fernando Reinaldo Ribeiro, María Vanessa Villasana, Maria Canavarro Teixeira and Eftim Zdravevski
Computers 2020, 9(3), 67; https://doi.org/10.3390/computers9030067 - 27 Aug 2020
Cited by 8 | Viewed by 4376
Abstract
The use of smartphones, coupled with different sensors, makes it an attractive solution for measuring different physical and physiological features, allowing for the monitoring of various parameters and even identifying some diseases. The BITalino device allows the use of different sensors, including Electroencephalography [...] Read more.
The use of smartphones, coupled with different sensors, makes it an attractive solution for measuring different physical and physiological features, allowing for the monitoring of various parameters and even identifying some diseases. The BITalino device allows the use of different sensors, including Electroencephalography (EEG) and Electrocardiography (ECG) sensors, to study different health parameters. With these devices, the acquisition of signals is straightforward, and it is possible to connect them using a Bluetooth connection. With the acquired data, it is possible to measure parameters such as calculating the QRS complex and its variation with ECG data to control the individual’s heartbeat. Similarly, by using the EEG sensor, one could analyze the individual’s brain activity and frequency. The purpose of this paper is to present a method for recognition of the diseases related to ECG and EEG data, with sensors available in off-the-shelf mobile devices and sensors connected to a BITalino device. The data were collected during the elderly’s experiences, performing the Timed-Up and Go test, and the different diseases found in the sample in the study. The data were analyzed, and the following features were extracted from the ECG, including heart rate, linear heart rate variability, the average QRS interval, the average R-R interval, and the average R-S interval, and the EEG, including frequency and variability. Finally, the diseases are correlated with different parameters, proving that there are relations between the individuals and the different health conditions. Full article
(This article belongs to the Special Issue Machine Learning for EEG Signal Processing)
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<p>Mobile application.</p> Full article ">Figure 2
<p>The 95% confidence interval for mean of interaction between Heart Rate with Diseases.</p> Full article ">Figure 3
<p>The 95% confidence interval for mean of interaction between Linear Heart Rate Variability with Diseases.</p> Full article ">Figure 4
<p>The 95% confidence interval for mean of interaction between Average of QRS interval with Diseases.</p> Full article ">Figure 5
<p>The 95% confidence interval for mean of interaction between Average of R-R interval with Diseases.</p> Full article ">Figure 6
<p>The 95% confidence interval for mean of interaction between Average of R-S interval with Diseases.</p> Full article ">Figure 7
<p>The 95% confidence interval for mean of interaction between Frequency of EEG with Diseases.</p> Full article ">Figure 8
<p>The 95% confidence interval for mean of interaction between Variability of EEG with Diseases.</p> Full article ">Figure 9
<p>Marginal estimated means of the interaction between diseases and parameters.</p> Full article ">
13 pages, 1494 KiB  
Article
An Efficient Secure Electronic Payment System for E-Commerce
by Md Arif Hassan, Zarina Shukur and Mohammad Kamrul Hasan
Computers 2020, 9(3), 66; https://doi.org/10.3390/computers9030066 - 27 Aug 2020
Cited by 44 | Viewed by 23258
Abstract
E-commerce implies an electronic purchasing and marketing process online by using typical Web browsers. As e-commerce is quickly developing on the planet, particularly in recent years, many areas of life are affected, particularly the improvement in how individuals regulate themselves non-financially and financially [...] Read more.
E-commerce implies an electronic purchasing and marketing process online by using typical Web browsers. As e-commerce is quickly developing on the planet, particularly in recent years, many areas of life are affected, particularly the improvement in how individuals regulate themselves non-financially and financially in different transactions. In electronic payment or e-commerce payment, the gateway is a major component of the structure to assure that such exchanges occur without disputes, while maintaining the common security over such systems. Most Internet payment gateways in e-commerce provide monetary information to customers using trusted third parties directly to a payment gateway. Nonetheless, it is recognized that the cloud Web server is not considered a protected entity. This article aims to develop an efficient and secure electronic payment protocol for e-commerce where consumers can immediately connect with the merchant properly. Interestingly, the proposed system does not require the customer to input his/her identity in the merchant’s website even though the customer can hide his/her identity and make a temporary identity to perform the service. It has been found that our protocol has much improved security effectiveness in terms of confidentiality, integrity, non-repudiation, anonymity availability, authentication, and authorization. Full article
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<p>How a payment gateway works [<a href="#B15-computers-09-00066" class="html-bibr">15</a>].</p> Full article ">Figure 2
<p>How RSA Public Key Cryptosystem works.</p> Full article ">Figure 3
<p>Proposed model of the e-payment system.</p> Full article ">Figure 4
<p>The proposed transaction phase protocol.</p> Full article ">
19 pages, 2435 KiB  
Article
Information Spread across Social Network Services with Non-Responsiveness of Individual Users
by Shigeo Shioda, Keisuke Nakajima and Masato Minamikawa
Computers 2020, 9(3), 65; https://doi.org/10.3390/computers9030065 - 13 Aug 2020
Cited by 7 | Viewed by 3403
Abstract
This paper investigates the dynamics of information spread across social network services (SNSs) such as Twitter using the susceptible-infected-recovered (SIR) model. In the analysis, the non-responsiveness of individual users is taken into account; a user probabilistically spreads the received information, where not spreading [...] Read more.
This paper investigates the dynamics of information spread across social network services (SNSs) such as Twitter using the susceptible-infected-recovered (SIR) model. In the analysis, the non-responsiveness of individual users is taken into account; a user probabilistically spreads the received information, where not spreading (not responding) is equivalent to that the received information is not noticed. In most practical applications, an exact analytic solution is not available for the SIR model, so previous studies have largely been based on the assumption that the probability of an SNS user having the target information is independent of whether or not its neighbors have that information. In contrast, we propose a different approach based on a “strong correlation assumption”, in which the probability of an SNS user having the target information is strongly correlated with whether its neighboring users have that information. To account for the non-responsiveness of individual users, we also propose the “representative-response-based analysis”, in which some information spreading patterns are first obtained assuming representative response patterns of each user and then the results are averaged. Through simulation experiments, we show that the combination of this strong correlation assumption and the representative-response-based analysis makes it possible to analyze the spread of information with far greater accuracy than the traditional approach. Full article
(This article belongs to the Special Issue Selected Papers from the 11th Computer Science and Electronic Engineering Conference (CEEC 2019))
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<p>State transition.</p> Full article ">Figure 2
<p>Temporal change in the number of retweets per minute: comparison between real data and simulation results based on the SIR model.</p> Full article ">Figure 3
<p>Temporal dependencies of <math display="inline"><semantics> <mi>λ</mi> </semantics></math> and <span class="html-italic">q</span>.</p> Full article ">Figure 4
<p>Tree-topology network.</p> Full article ">Figure 5
<p>Number of broadcasts per 0.1 time units (<math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>1</mn> </mrow> </semantics></math>): (<b>a</b>) on Facebook, (<b>b</b>) on Twitter.</p> Full article ">Figure 6
<p>Number of broadcasts per 0.1 time units on Facebook: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.1</mn> </mrow> </semantics></math>, (<b>d</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.05</mn> </mrow> </semantics></math>.</p> Full article ">Figure 7
<p>Cumulative number of broadcasts on Facebook: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.1</mn> </mrow> </semantics></math>, (<b>d</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.05</mn> </mrow> </semantics></math>.</p> Full article ">Figure 8
<p>Number of broadcasts per 0.1 time units on Twitter: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.1</mn> </mrow> </semantics></math>, (<b>d</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.05</mn> </mrow> </semantics></math>.</p> Full article ">Figure 9
<p>Cumulative number of broadcasts on Twitter: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.5</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.1</mn> </mrow> </semantics></math>, (<b>d</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.05</mn> </mrow> </semantics></math>.</p> Full article ">Figure 10
<p>Dependence on the outcome of the response matrix on Facebook: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.1</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.05</mn> </mrow> </semantics></math>.</p> Full article ">Figure 11
<p>Dependence on the outcome of the response matrix on Twitter: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.1</mn> </mrow> </semantics></math>, (<b>c</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.05</mn> </mrow> </semantics></math>.</p> Full article ">Figure 12
<p>Mean-field approximation on Facebook: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>.</p> Full article ">Figure 13
<p>Mean-field approximation on Twitter: (<b>a</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>, (<b>b</b>) <math display="inline"><semantics> <mrow> <mi>q</mi> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>.</p> Full article ">
16 pages, 1188 KiB  
Article
Privacy-Preserving Passive DNS
by Pavlos Papadopoulos, Nikolaos Pitropakis, William J. Buchanan, Owen Lo and Sokratis Katsikas
Computers 2020, 9(3), 64; https://doi.org/10.3390/computers9030064 - 12 Aug 2020
Cited by 12 | Viewed by 6665
Abstract
The Domain Name System (DNS) was created to resolve the IP addresses of web servers to easily remembered names. When it was initially created, security was not a major concern; nowadays, this lack of inherent security and trust has exposed the global DNS [...] Read more.
The Domain Name System (DNS) was created to resolve the IP addresses of web servers to easily remembered names. When it was initially created, security was not a major concern; nowadays, this lack of inherent security and trust has exposed the global DNS infrastructure to malicious actors. The passive DNS data collection process creates a database containing various DNS data elements, some of which are personal and need to be protected to preserve the privacy of the end users. To this end, we propose the use of distributed ledger technology. We use Hyperledger Fabric to create a permissioned blockchain, which only authorized entities can access. The proposed solution supports queries for storing and retrieving data from the blockchain ledger, allowing the use of the passive DNS database for further analysis, e.g., for the identification of malicious domain names. Additionally, it effectively protects the DNS personal data from unauthorized entities, including the administrators that can act as potential malicious insiders, and allows only the data owners to perform queries over these data. We evaluated our proposed solution by creating a proof-of-concept experimental setup that passively collects DNS data from a network and then uses the distributed ledger technology to store the data in an immutable ledger, thus providing a full historical overview of all the records. Full article
(This article belongs to the Special Issue Feature Paper in Computers)
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<p>Overview of the Domain Name System (DNS).</p> Full article ">Figure 2
<p>Privacy Preserving Passive (PRESERVE DNS) proof-of-concept implementation architecture for the test data collection.</p> Full article ">Figure 3
<p>Hyperledger fabric infrastructure.</p> Full article ">Figure 4
<p>Read Data transactions overhead.</p> Full article ">Figure 5
<p>CPU Usage (%) of Nodes during workflow.</p> Full article ">Figure 5 Cont.
<p>CPU Usage (%) of Nodes during workflow.</p> Full article ">Figure 6
<p>Memory Usage (%) of Nodes during workflow on 1000, 10,000 and 100,000 DNS Entries.</p> Full article ">
23 pages, 412 KiB  
Article
Addressing Bandwidth-Driven Flow Allocationin RINA
by Michal Koutenský, Vladimír Veselý and Vincenzo Maffione
Computers 2020, 9(3), 63; https://doi.org/10.3390/computers9030063 - 10 Aug 2020
Cited by 1 | Viewed by 3250
Abstract
Effective capacity allocation is essential for a network to operate properly, providing predictable quality of service guarantees and avoiding bottlenecks. Achieving capacity allocation fairness is a long-standing problem extensively researched in the frame of transport and network layer protocols such as TCP/IP. The [...] Read more.
Effective capacity allocation is essential for a network to operate properly, providing predictable quality of service guarantees and avoiding bottlenecks. Achieving capacity allocation fairness is a long-standing problem extensively researched in the frame of transport and network layer protocols such as TCP/IP. The Recursive InterNetwork Architecture offers programmable policies that enable more flexible control on the mechanics of network flow allocation. In this paper, we present our version of one of these policies, which provides flow allocation according to the bandwidth requirements of requesting applications. We implement the bandwidth-aware flow allocation policy by extending rlite, an open source RINA implementation. Our evaluation shows how the policy can prevent links from becoming oversaturated and use alternate paths to achieve high total link data-rate use. Full article
(This article belongs to the Special Issue Post-IP Networks: Advances on RINA and other Alternative Network Architectures)
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<p>Three PSs <span class="html-italic">A</span>, <span class="html-italic">B</span> and <span class="html-italic">C</span> connected with physical links.</p> Full article ">Figure 2
<p>Three PSs <span class="html-italic">A</span>, <span class="html-italic">B</span>, and <span class="html-italic">C</span> connected with physical links. A DIF is created over every link allowing pairs of PSs to communicate.</p> Full article ">Figure 3
<p>Three PSs <span class="html-italic">A</span>, <span class="html-italic">B</span>, and <span class="html-italic">C</span> connected with physical links. A DIF is created over every link allowing pairs of PSs to communicate. An additional DIF is created over the link DIFs, joining all three PSs in a shared communication domain.</p> Full article ">Figure 4
<p>The rlite architecture.</p> Full article ">Figure 5
<p>Overview of the flow allocation process. Horizontal arrows represent direct communication; diagonal arrows are communications with other replicas within the Raft cluster or between the Raft cluster and nodes along the reserved path; the yellow box is an action done within the IPCP.</p> Full article ">Figure 6
<p>The status of the RIB of a Raft replica while running a <tt>rinaperf</tt> test application, requesting 40 Mbps per flow, with two active flows. The flow reservation table lists two entries, and the available bandwidth has decreased accordingly. The output is not complete, as some parts have been edited or omitted for brevity.</p> Full article ">Figure 7
<p>A basic test for the graph algorithm to check that it respects the capacity condition. (<b>a</b>) The result of searching for a path from <span class="html-italic">N0</span> to <span class="html-italic">N2</span> of size 5; (<b>b</b>) the result of searching for a path from <span class="html-italic">N0</span> to <span class="html-italic">N3</span> of size 10.</p> Full article ">Figure 8
<p>Another unit test for the graph algorithm. It successfully finds the only possible path from <span class="html-italic">N3</span> to <span class="html-italic">N7</span> of size 10.</p> Full article ">Figure 9
<p>Better bandwidth use as a result of per-flow routing. (<b>a</b>) shows complete saturation of the inner links while an alternate path remains unused. In (<b>b</b>), there is almost double the traffic flowing through the network, as it can use all available paths.</p> Full article ">Figure 10
<p>Scenario with 10 nodes: Visualization of link use after (<b>a</b>) 16, (<b>b</b>) 32, (<b>c</b>) 48, (<b>d</b>) 64 <tt>rinaperf</tt> instances have been started on randomly selected nodes.</p> Full article ">Figure 11
<p>Scenario with 10 nodes: (<b>a</b>) Success of flow allocation requests over time; (<b>b</b>) link use over time. The value <span class="html-italic">max</span> shows the use of the link with the most traffic flowing through it at that point in time; <span class="html-italic">mean</span> is the average link use across the network.</p> Full article ">Figure 12
<p>Scenario with 20 nodes: Visualization of link use after (<b>a</b>) 25, (<b>b</b>) 50, (<b>c</b>) 75, (<b>d</b>) 100 <tt>rinaperf</tt> instances have been randomly started.</p> Full article ">Figure 13
<p>Scenario with 20 nodes: (<b>a</b>) Success of flow allocation requests over time; (<b>b</b>) link use over time. The value <span class="html-italic">max</span> shows the use of the link with the most traffic flowing through it at that point in time; <span class="html-italic">mean</span> is the average link use across the network.</p> Full article ">Figure 14
<p>Comparison of maximum flow from N6 to N9 in the network from <a href="#computers-09-00063-f010" class="html-fig">Figure 10</a>. Both nodes act as “supersinks” and have had the capacity of their edges increased to infinity. (<b>a</b>) shows the results obtained using the Ford-Fulkerson maximum flow algorithm. (<b>b</b>) shows results obtained using our implemented policy.</p> Full article ">Figure 15
<p>Comparison of maximum flow from N18 to N2 in the network from <a href="#computers-09-00063-f012" class="html-fig">Figure 12</a>. Both nodes act as “supersinks” and have had the capacity of their edges increased to infinity. (<b>a</b>) shows the results obtained using the Ford-Fulkerson maximum flow algorithm. (<b>b</b>) shows results obtained using our implemented policy.</p> Full article ">Figure 16
<p>Comparison of flow allocation delay for the scenario from <a href="#computers-09-00063-f010" class="html-fig">Figure 10</a>. The box edges correspond to the first and third quartiles, with a bolder line representing the median value. Outliers are shown as dots.</p> Full article ">Figure 17
<p>Comparison of flow allocation delay for the scenario from <a href="#computers-09-00063-f012" class="html-fig">Figure 12</a>. The box edges correspond to the first and third quartiles, with a bolder line representing the median value. Outliers are shown as dots.</p> Full article ">Figure 18
<p>Improvements in bandwidth use effectiveness through algorithm modification. A network with three sites (<span class="html-italic">A</span>, <span class="html-italic">E</span> and <span class="html-italic">G</span>) connected using two redundant paths. In both cases, a flow from <span class="html-italic">A</span> to <span class="html-italic">G</span> of size 5 has been allocated. In (<b>a</b>), corresponding to the current algorithm, a path through <span class="html-italic">D</span> might be selected, depending on the traversal order. This completely cuts off site <span class="html-italic">E</span> from the rest of the network, even though there is enough bandwidth. Conversely, an algorithm with the proposed prioritizing modification in (<b>b</b>) avoids this by selecting the alternate route first.</p> Full article ">
11 pages, 4534 KiB  
Article
Possibilities of Electromagnetic Penetration of Displays of Multifunction Devices
by Ireneusz Kubiak, Artur Przybysz and Slawomir Musial
Computers 2020, 9(3), 62; https://doi.org/10.3390/computers9030062 - 8 Aug 2020
Cited by 6 | Viewed by 6605
Abstract
A protection of information against electromagnetic penetration is very often considered in the aspect of the possibility of obtaining data contained in printed documents or displayed on screen monitors. However, many printing devices are equipped with screens based on LED technology or liquid [...] Read more.
A protection of information against electromagnetic penetration is very often considered in the aspect of the possibility of obtaining data contained in printed documents or displayed on screen monitors. However, many printing devices are equipped with screens based on LED technology or liquid crystal displays. Options enabling the selection of parameters of the printed document, technical settings of the device (e.g., screen activity time) are the most frequently displayed information. For more extensive displays, more detailed information appears, which may contain data that are not always irrelevant to third parties. Such data can be: names of printed documents (or documents registered and available on the internal media), service password access, user names or regular printer user activity. The printer display can be treated as a source of revealing emissions, like a typical screen monitor. The emissions correlated with the displayed data may allow us to obtain the abovementioned information. The article includes analyses of various types of computer printer displays. The tests results of the existing threat are presented in the form of reconstructed images that show the possibility of reading the text data contained in them. Full article
(This article belongs to the Special Issue Feature Paper in Computers)
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<p>Image obtained on the basis of revealing emission measured on frequency <span class="html-italic">f<sub>o</sub></span> = 365 MHz (<span class="html-italic">BW</span> = 50 MHz) for the source in form of DVI standard (resolution 800 × 600, 60 Hz): (<b>a</b>) Arial font, (<b>b</b>) Times New Roman font.</p> Full article ">Figure 2
<p>Image obtained on the basis of revealing emission measured on frequency <span class="html-italic">f<sub>o</sub></span> = 365 MHz (<span class="html-italic">BW</span> = 50 MHz) for the source in form of DVI standard (resolution 800 × 600, 60 Hz), from the top: Secure Symmetrical font (first and second lines), Secure Asymmetrical font (third and fourth lines), Secure Simple font (fifth and sixth lines).</p> Full article ">Figure 3
<p>Four different laser printers used during tests of valuable emissions from displays: (<b>a</b>) Color Laser Jet Pro MFP M477fdn, (<b>b</b>) Color Laser Jet Pro MFP M277dw, (<b>c</b>) Lexmark MS610DE (a source: <a href="https://www.lexmark.com/pl_pl/printer/7693/Lexmark-MS610dn" target="_blank">https://www.lexmark.com/pl_pl/printer/7693/Lexmark-MS610dn</a>), (<b>d</b>) HP 507 (a source: <a href="https://www8.hp.com/pl_pl/printers/product-details/19203858" target="_blank">https://www8.hp.com/pl_pl/printers/product-details/19203858</a>).</p> Full article ">Figure 4
<p>Data serialization process in case of 8-bit coding.</p> Full article ">Figure 5
<p>Measuring system.</p> Full article ">Figure 6
<p>A real measuring system.</p> Full article ">Figure 7
<p>Images obtained on the basis of revealing emissions (<span class="html-italic">f<sub>o</sub></span> = 235 MHz, BW = 20 MHz (<b>a</b>), 10 MHz (<b>b</b>), 5 MHz (<b>c</b>)) for the sources in form of printer displays (<a href="#computers-09-00062-f003" class="html-fig">Figure 3</a>a).</p> Full article ">Figure 8
<p>Image obtained on the basis of revealing emissions measured on frequency <span class="html-italic">f<sub>o</sub></span> = 411 MHz (<span class="html-italic">BW</span> = 10 MHz) for the source in form of printer display (<a href="#computers-09-00062-f003" class="html-fig">Figure 3</a>b).</p> Full article ">Figure 9
<p>Image obtained on the basis of revealing emission measured on frequency <span class="html-italic">f<sub>o</sub></span> = 15 MHz (<span class="html-italic">BW</span> = 5 MHz) for the source in form of printer display (<a href="#computers-09-00062-f003" class="html-fig">Figure 3</a>c).</p> Full article ">Figure 10
<p>Image obtained on the basis of revealing emission measured on frequency <span class="html-italic">f<sub>o</sub></span> = 1177 MHz (<span class="html-italic">BW</span> = 100 MHz) for the source in form of printer display (<a href="#computers-09-00062-f003" class="html-fig">Figure 3</a>d).</p> Full article ">Figure 11
<p>Examples of multifunctional devices equipped with large size displays: (<b>a</b>) Lexmark X651DE (<a href="https://www.lexmark.com/pl_pl/printer/4831/Lexmark-X651de" target="_blank">https://www.lexmark.com/pl_pl/printer/4831/Lexmark-X651de</a>), (<b>b</b>) HP M525f MFP (source: <a href="https://sklephp.pl/drukarki/urzadzenie-wielofunkcyjne-hp-laserjet-enterprise-500-mfp-m525dn" target="_blank">https://sklephp.pl/drukarki/urzadzenie-wielofunkcyjne-hp-laserjet-enterprise-500-mfp-m525dn</a>).</p> Full article ">
12 pages, 381 KiB  
Article
Increasing Innovative Working Behaviour of Information Technology Employees in Vietnam by Knowledge Management Approach
by Quoc Trung Pham, Anh-Vu Pham-Nguyen, Sanjay Misra and Robertas Damaševičius
Computers 2020, 9(3), 61; https://doi.org/10.3390/computers9030061 - 1 Aug 2020
Cited by 12 | Viewed by 5948
Abstract
Today, Knowledge Management (KM) is becoming a popular approach for improving organizational innovation, but whether encouraging knowledge sharing will lead to a better innovative working behaviour of employees is still a question. This study aims to identify the factors of KM affecting the [...] Read more.
Today, Knowledge Management (KM) is becoming a popular approach for improving organizational innovation, but whether encouraging knowledge sharing will lead to a better innovative working behaviour of employees is still a question. This study aims to identify the factors of KM affecting the innovative working behaviour of Information Technology (IT) employees in Vietnam. The research model involves three elements: attitude, subjective norm and perceived behavioural control affecting knowledge sharing, and then, on innovative working behaviour. The research method is the quantitative method. The survey was conducted with 202 samples via the five-scale questionnaire. The analysis results show that knowledge sharing has a positive impact on the innovative working behaviour of IT employees in Vietnam. Besides, attitude and perceived behavioural control are confirmed to have a strong positive effect on knowledge sharing, but the subjective norm has no significant impact on knowledge sharing. Based on this result, recommendations to promote knowledge sharing and the innovative work behaviour of IT employees in Vietnam are made. Full article
(This article belongs to the Special Issue Feature Paper in Computers)
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<p>The proposed research model.</p> Full article ">
18 pages, 757 KiB  
Article
Predicting LoRaWAN Behavior: How Machine Learning Can Help
by Francesca Cuomo, Domenico Garlisi, Alessio Martino and Antonio Martino
Computers 2020, 9(3), 60; https://doi.org/10.3390/computers9030060 - 31 Jul 2020
Cited by 22 | Viewed by 6017
Abstract
Large scale deployments of Internet of Things (IoT) networks are becoming reality. From a technology perspective, a lot of information related to device parameters, channel states, network and application data are stored in databases and can be used for an extensive analysis to [...] Read more.
Large scale deployments of Internet of Things (IoT) networks are becoming reality. From a technology perspective, a lot of information related to device parameters, channel states, network and application data are stored in databases and can be used for an extensive analysis to improve the functionality of IoT systems in terms of network performance and user services. LoRaWAN (Long Range Wide Area Network) is one of the emerging IoT technologies, with a simple protocol based on LoRa modulation. In this work, we discuss how machine learning approaches can be used to improve network performance (and if and how they can help). To this aim, we describe a methodology to process LoRaWAN packets and apply a machine learning pipeline to: (i) perform device profiling, and (ii) predict the inter-arrival of IoT packets. This latter analysis is very related to the channel and network usage and can be leveraged in the future for system performance enhancements. Our analysis mainly focuses on the use of k-means, Long Short-Term Memory Neural Networks and Decision Trees. We test these approaches on a real large-scale LoRaWAN network where the overall captured traffic is stored in a proprietary database. Our study shows how profiling techniques enable a machine learning prediction algorithm even when training is not possible because of high error rates perceived by some devices. In this challenging case, the prediction of the inter-arrival time of packets has an error of about 3.5% for 77% of real sequence cases. Full article
(This article belongs to the Special Issue Feature Paper in Computers)
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<p>Long Range Wide Area Network (LoRaWAN) network architecture.</p> Full article ">Figure 2
<p>Number of received packets per week in a period of one year for the water meter dataset.</p> Full article ">Figure 3
<p>End Devices (EDs) representation in terms of SNR, Error Rate and SF after the <span class="html-italic">k</span>-means clustering. Different ED clusters are represented by different colours.</p> Full article ">Figure 4
<p>Pattern of the Inter-arrival Times (ITs) for the LoRaWAN water metering EDs.</p> Full article ">Figure 5
<p>Frequency analysis for the ITs for a subset of water metering EDs.</p> Full article ">Figure 6
<p>Example of the Decision Tree (DT) representation resulting from our dataset (for a window <math display="inline"><semantics> <mrow> <mi>n</mi> <mo>=</mo> <mn>2</mn> </mrow> </semantics></math> and maximum depth of three splits).</p> Full article ">Figure 7
<p>Long Short Term Memory (LSTM) cell architecture.</p> Full article ">Figure 8
<p>Twenty-fold cross validation on training set with different window sizes (<b>a</b>). Qualitative result of the DT prediction for the test dataset (<b>b</b>). Qualitative result of the LSTM prediction for the test dataset (<b>c</b>). CDF of the absolute prediction errors of the DT for the four datasets (<b>d</b>). CDF of the absolute prediction errors of the LSTM for the four datasets (<b>e</b>).</p> Full article ">
22 pages, 7877 KiB  
Article
ARCFIRE: Experimentation with the Recursive InterNetwork Architecture
by Sander Vrijders, Dimitri Staessens, Didier Colle, Eduard Grasa, Miquel Tarzan, Sven van der Meer, Marco Capitani, Vincenzo Maffione, Diego Lopez, Lou Chitkushev and John Day
Computers 2020, 9(3), 59; https://doi.org/10.3390/computers9030059 - 22 Jul 2020
Cited by 1 | Viewed by 4093
Abstract
European funded research into the Recursive Inter-Network Architecture (RINA) started with IRATI, which developed an initial prototype implementation for OS/Linux. IRATI was quickly succeeded by the PRISTINE project, which developed different policies, each tailored to specific use cases. Both projects were development-driven, where [...] Read more.
European funded research into the Recursive Inter-Network Architecture (RINA) started with IRATI, which developed an initial prototype implementation for OS/Linux. IRATI was quickly succeeded by the PRISTINE project, which developed different policies, each tailored to specific use cases. Both projects were development-driven, where most experimentation was limited to unit testing and smaller scale integration testing. In order to assess the viability of RINA as an alternative to current network technologies, larger scale experimental deployments are needed. The opportunity arose for a project that shifted focus from development towards experimentation, leveraging Europe’s investment in Future Internet Research and Experimentation (FIRE+) infrastructures. The ARCFIRE project took this next step, developing a user-friendly framework for automating RINA experiments. This paper reports and discusses the implications of the experimental results achieved by the ARCFIRE project, using open source RINA implementations deployed on FIRE+ Testbeds. Experiments analyze the properties of RINA relevant to fast network recovery, network renumbering, Quality of Service, distributed mobility management, and network management. Results highlight RINA properties that can greatly simplify the deployment and management of real-world networks; hence, the next steps should be focused on addressing very specific use cases with complete network RINA-based networking solutions that can be transferred to the market. Full article
(This article belongs to the Special Issue Post-IP Networks: Advances on RINA and other Alternative Network Architectures)
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<p>High-level view of a Converged Operator Network (CON) as considered by ARCFIRE.</p> Full article ">Figure 2
<p>Example design for a CON: fixed residential access.</p> Full article ">Figure 3
<p>Example DIF design for a Converged Operator Network: cellular access.</p> Full article ">Figure 4
<p>GEANT Network physical connectivity graph and DIF structure used in the experiment.</p> Full article ">Figure 5
<p>RTT (Round Trip Time) for some of the paths involving Ljubljana.</p> Full article ">Figure 6
<p>DIF configurations for the renumbering experiments.</p> Full article ">Figure 7
<p>Application RTT, measured with and without renumbering, for each flow.</p> Full article ">Figure 8
<p>Systems and DIFs in the RINA-based QoS-enabled Virtual Private Network experiment.</p> Full article ">Figure 9
<p>End-to-end delay Cumulative Distribution Function (CDF) for flows between PEs, using QTAMux (<b>left</b>) and FIFO (<b>right</b>) schedulers in the DIF. QoS1 and QoS3 are the urgent classes.</p> Full article ">Figure 10
<p>Physical systems in the multi-layer QoS experiment.</p> Full article ">Figure 11
<p>CDF of delay at systems CPE63 and CPE41, for multiple flows with different QoS requirements.</p> Full article ">Figure 12
<p>Physical systems present at the distributed mobility management experiment.</p> Full article ">Figure 13
<p>Physical systems present at the distributed mobility management experiment.</p> Full article ">Figure 14
<p>Visualizing a RINA network with an onion diagram.</p> Full article ">Figure 15
<p>Validating the RINA network on <a href="#computers-09-00059-f012" class="html-fig">Figure 12</a>.</p> Full article ">
14 pages, 1081 KiB  
Article
An Adversarial Approach for Intrusion Detection Systems Using Jacobian Saliency Map Attacks (JSMA) Algorithm
by Ayyaz Ul Haq Qureshi, Hadi Larijani, Mehdi Yousefi, Ahsan Adeel and Nhamoinesu Mtetwa
Computers 2020, 9(3), 58; https://doi.org/10.3390/computers9030058 - 20 Jul 2020
Cited by 19 | Viewed by 4854
Abstract
In today’s digital world, the information systems are revolutionizing the way we connect. As the people are trying to adopt and integrate intelligent systems into daily lives, the risks around cyberattacks on user-specific information have significantly grown. To ensure safe communication, the Intrusion [...] Read more.
In today’s digital world, the information systems are revolutionizing the way we connect. As the people are trying to adopt and integrate intelligent systems into daily lives, the risks around cyberattacks on user-specific information have significantly grown. To ensure safe communication, the Intrusion Detection Systems (IDS) were developed often by using machine learning (ML) algorithms that have the unique ability to detect malware against network security violations. Recently, it was reported that the IDS are prone to carefully crafted perturbations known as adversaries. With the aim to understand the impact of such attacks, in this paper, we have proposed a novel random neural network-based adversarial intrusion detection system (RNN-ADV). The NSL-KDD dataset is utilized for training. For adversarial attack crafting, the Jacobian Saliency Map Attack (JSMA) algorithm is used, which identifies the feature which can cause maximum change to the benign samples with minimum added perturbation. To check the effectiveness of the proposed adversarial scheme, the results are compared with a deep neural network which indicates that RNN-ADV performs better in terms of accuracy, precision, recall, F1 score and training epochs. Full article
(This article belongs to the Special Issue Feature Paper in Computers)
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<p>Random neural network model for adversarial analytics.</p> Full article ">Figure 2
<p>Adversarial attack crafting using Jacobian saliency map attacks (JSMA) algorithm.</p> Full article ">Figure 3
<p>Performance comparison between adversarial RNN-ADV and MLP.</p> Full article ">Figure 4
<p>RNN-ADV output confidence based on harmonic mean of precision and recall values.</p> Full article ">
16 pages, 699 KiB  
Article
ERF: An Empirical Recommender Framework for Ascertaining Appropriate Learning Materials from Stack Overflow Discussions
by Ashesh Iqbal, Sumi Khatun, Mohammad Shamsul Arefin and M. Ali Akber Dewan
Computers 2020, 9(3), 57; https://doi.org/10.3390/computers9030057 - 20 Jul 2020
Viewed by 3693
Abstract
Computer programmers require various instructive information during coding and development. Such information is dispersed in different sources like language documentation, wikis, and forums. As an information exchange platform, programmers broadly utilize Stack Overflow, a Web-based Question Answering site. In this paper, we propose [...] Read more.
Computer programmers require various instructive information during coding and development. Such information is dispersed in different sources like language documentation, wikis, and forums. As an information exchange platform, programmers broadly utilize Stack Overflow, a Web-based Question Answering site. In this paper, we propose a recommender system which uses a supervised machine learning approach to investigate Stack Overflow posts to present instructive information for the programmers. This might be helpful for the programmers to solve programming problems that they confront with in their daily life. We analyzed posts related to two most popular programming languages—Python and PHP. We performed a few trials and found that the supervised approach could effectively manifold valuable information from our corpus. We validated the performance of our system from human perception which showed an accuracy of 71%. We also presented an interactive interface for the users that satisfied the users’ query with the matching sentences with most instructive information. Full article
(This article belongs to the Special Issue Feature Paper in Computers)
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<p>System architecture of the proposed framework.</p> Full article ">Figure 2
<p>User interface.</p> Full article ">
29 pages, 3391 KiB  
Article
Automatic Code Generation of MVC Web Applications
by Gaetanino Paolone, Martina Marinelli, Romolo Paesani and Paolino Di Felice
Computers 2020, 9(3), 56; https://doi.org/10.3390/computers9030056 - 15 Jul 2020
Cited by 22 | Viewed by 11004
Abstract
As Web applications become more and more complex, the development costs are increasing as well. A Model Driven Architecture (MDA) approach is proposed in this paper since it simplifies modeling, design, implementation, and integration of applications by defining software mainly at the model [...] Read more.
As Web applications become more and more complex, the development costs are increasing as well. A Model Driven Architecture (MDA) approach is proposed in this paper since it simplifies modeling, design, implementation, and integration of applications by defining software mainly at the model level. We adopt the The Unified Modeling Language (UML), as modeling language. UML provides a set of diagrams to model structural and behavioral aspects of the Web applications. Automatic translation of UML diagrams to the Object-Oriented code is highly desirable because it eliminates the chances of introducing human errors. Moreover, automatic code generation helps the software designers delivering of the software on time. In our approach, the automatic transformations across the MDA’s levels are based on meta-models for two of the most important constructs of UML, namely Use Cases and classes. A proprietary tool (called xGenerator) performs the transformations up to the Java source code. The architecture of the generated Web applications respects a variant of the well-known Model-View-Controller (MVC) pattern. Full article
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<p>The Model-View-Controller (MVC) pattern of an enterprise Web application.</p> Full article ">Figure 2
<p>The two levels of the <span class="html-italic">generation gap</span> pattern.</p> Full article ">Figure 3
<p>The UC abstraction levels across the MDA layers.</p> Full article ">Figure 4
<p>The UML constructs and the Rules at the CIM.</p> Full article ">Figure 5
<p>The UML constructs for the PIM.</p> Full article ">Figure 6
<p>The UML classes at the PSM.</p> Full article ">Figure 7
<p>The Java classes of the Web application.</p> Full article ">Figure 8
<p>Overview of the proposed MDA transformational approach.</p> Full article ">Figure 9
<p>The UML meta-model of the Domain Class.</p> Full article ">Figure 10
<p>The UML meta-model of the Use Case.</p> Full article ">Figure 11
<p>The UML meta-model of the Panel Class: (<b>a</b>) Bean classes; (<b>b</b>) Graphical User Interfaces.</p> Full article ">Figure 12
<p>(<b>a</b>) The four modeling views of the <tt>ATMProject</tt>; (<b>b</b>) the packages of the <tt>Use Case View</tt> and <tt>Logical View</tt> at the first level of nesting; (<b>c</b>) the packages of the <tt>Use Case View</tt> and <tt>Logical View</tt> at the second level of nesting.</p> Full article ">Figure 13
<p>The diagram of the <tt>Withdraw</tt> Business UC Realization.</p> Full article ">Figure 14
<p>The names of the business scenarios of the <tt>Withdraw</tt> Business UC Realization.</p> Full article ">Figure 15
<p>The sequence diagram of the business scenario <tt>Select Operation</tt>.</p> Full article ">Figure 16
<p>The sequence diagrams of the business scenario <tt>Withdraw</tt>.</p> Full article ">Figure 17
<p>The sequence diagrams of the business scenario <tt>Account Balance</tt>.</p> Full article ">Figure 18
<p>The sequence diagrams of the business scenario <tt>Transaction List</tt>.</p> Full article ">Figure 19
<p>The names of the boundary classes of the <tt>Withdraw</tt> Business UC Realization.</p> Full article ">Figure 20
<p>The diagram of the Business Objects.</p> Full article ">Figure 21
<p>The Domain class diagram.</p> Full article ">Figure 22
<p>The System UC Realization diagram.</p> Full article ">Figure 23
<p>The names of the system scenarios of the <tt>Withdraw</tt> System UC Realization.</p> Full article ">Figure 24
<p>The sequence diagram of the system scenario <tt>Select Operation</tt>.</p> Full article ">Figure 25
<p>The sequence diagrams of the system scenario <tt>Withdraw</tt>.</p> Full article ">Figure 26
<p>The sequence diagrams of the system scenario <tt>Account Balance.</tt></p> Full article ">Figure 27
<p>The sequence diagrams of the system scenario <tt>Transaction List</tt>.</p> Full article ">Figure 28
<p>The architectural layers of the source code to be generated.</p> Full article ">Figure 29
<p>The architectural layers at PSM: (<b>a</b>) the <tt>Bean</tt> classes; (<b>b</b>) the <tt>UseCase</tt> classes; (<b>c</b>) the View layer.</p> Full article ">Figure 30
<p>The detailed architectural layers at PSM: (<b>a</b>) the <tt>QueryContainer</tt> classes; (<b>b</b>) the <tt>ViewBeanInfo</tt> classes; (<b>c</b>) the panels of the <tt>Withdraw</tt> UC.</p> Full article ">Figure 31
<p>The class diagrams for the <tt>Withdraw</tt> System UC Realization: (<b>a</b>) <tt>Model Bean</tt> classes; (<b>b</b>) <tt>Model QueryContainer</tt> classes; (<b>c</b>) <tt>Controller</tt> classes; (<b>d</b>) <tt>ViewQueryContainer</tt> classes; (<b>e</b>) <tt>Panel</tt> classes.</p> Full article ">Figure 32
<p>The Graphical User Interface that matches the <tt>Withdraw</tt> System UC Realization (<b>left</b>). An example of withdrawal (<b>right</b>).</p> Full article ">Figure 33
<p>The Eclipse’s packages of the <tt>Java ATMProject</tt>.</p> Full article ">Figure 34
<p>Code of the <tt>UseCasePanelWithdraw.java</tt> class.</p> Full article ">Figure 35
<p>Overview of the approach in Reference [<a href="#B41-computers-09-00056" class="html-bibr">41</a>].</p> Full article ">Figure A1
<p>The Component diagram of <tt>xGenerator</tt>.</p> Full article ">Figure A2
<p>The architecture of the Web applications developed with <tt>xGenerator</tt>.</p> Full article ">
14 pages, 3703 KiB  
Article
Machine Learning Techniques with ECG and EEG Data: An Exploratory Study
by Vasco Ponciano, Ivan Miguel Pires, Fernando Reinaldo Ribeiro, Nuno M. Garcia, María Vanessa Villasana, Eftim Zdravevski and Petre Lameski
Computers 2020, 9(3), 55; https://doi.org/10.3390/computers9030055 - 29 Jun 2020
Cited by 11 | Viewed by 6308
Abstract
Electrocardiography (ECG) and electroencephalography (EEG) are powerful tools in medicine for the analysis of various diseases. The emergence of affordable ECG and EEG sensors and ubiquitous mobile devices provides an opportunity to make such analysis accessible to everyone. In this paper, we propose [...] Read more.
Electrocardiography (ECG) and electroencephalography (EEG) are powerful tools in medicine for the analysis of various diseases. The emergence of affordable ECG and EEG sensors and ubiquitous mobile devices provides an opportunity to make such analysis accessible to everyone. In this paper, we propose the implementation of a neural network-based method for the automatic identification of the relationship between the previously known conditions of older adults and the different features calculated from the various signals. The data were collected using a smartphone and low-cost ECG and EEG sensors during the performance of the timed-up and go test. Different patterns related to the features extracted, such as heart rate, heart rate variability, average QRS amplitude, average R-R interval, and average R-S interval from ECG data, and the frequency and variability from the EEG data were identified. A combination of these parameters allowed us to identify the presence of certain diseases accurately. The analysis revealed that the different institutions and ages were mainly identified. Still, the various diseases and groups of diseases were difficult to recognize, because the frequency of the different diseases was rare in the considered population. Therefore, the test should be performed with more people to achieve better results. Full article
(This article belongs to the Special Issue Machine Learning for EEG Signal Processing)
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<p>Flow of the analysis of the collected data.</p> Full article ">Figure 2
<p>Descriptive analysis of the data by Institution.</p> Full article ">Figure 3
<p>Plot dispersion of the classified data by Institution.</p> Full article ">Figure 4
<p>Descriptive analysis of the data by age.</p> Full article ">Figure 5
<p>Plot dispersion of the classified data by age.</p> Full article ">Figure 6
<p>Descriptive analysis of the data related by disease.</p> Full article ">Figure 7
<p>Plot dispersion of the classified data by disease.</p> Full article ">Figure 8
<p>Descriptive analysis of the data related by groups of diseases.</p> Full article ">Figure 9
<p>Plot dispersion of the classified data by groups of diseases.</p> Full article ">
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