Technologies

20 pages, 1692 KiB

Open AccessFeature PaperArticle

An Acoustic-Based Smart Home System for People Suffering from Dementia

by Eleni Boumpa, Anargyros Gkogkidis, Ioanna Charalampou, Argyro Ntaliani, Athanasios Kakarountas and Vasileios Kokkinos

Technologies 2019, 7(1), 29; https://doi.org/10.3390/technologies7010029 - 12 Mar 2019

Cited by 14 | Viewed by 7588

Abstract

Aging-in-place can reduce the progress of dementia syndrome and improve the quality of life of the sufferers and their families. Taking into consideration the fact that numerous neurological research results suggest the use of sound as a stimulus for empowering the memory of [...] Read more.

Aging-in-place can reduce the progress of dementia syndrome and improve the quality of life of the sufferers and their families. Taking into consideration the fact that numerous neurological research results suggest the use of sound as a stimulus for empowering the memory of the sufferer, an innovative information home support system for people suffering from dementia is proposed. The innovation of the proposed system is found in its application, that is to integrate a home system for assisting with person recognition via a sound-based memory aid service. Furthermore, the system addresses the needs of people suffering from dementia to recognize their familiars and have better interaction and collaboration, without the need for training. The system offers a ubiquitous recognition system, using smart devices like smart-phones or smart-wristbands. When a familiar person is detected in the house, then a sound is reproduced on the smart speakers, in order to stimulate the sufferer’s memory. The system identified all users and reproduced the appropriate sound in 100% of the cases. To the best of the authors’ knowledge, this is the first system of its kind for assisting person recognition via sound ever reported in the literature. Full article

(This article belongs to the Special Issue Smart Homes and Assisted Living for Ageing Population: From Sensors to Services)

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20 pages, 8069 KiB

Open AccessArticle

A Novel Chip-Level Blockchain Security Solution for the Internet of Things Networks

by Hiroshi Watanabe and Howie Fan

Technologies 2019, 7(1), 28; https://doi.org/10.3390/technologies7010028 - 7 Mar 2019

Cited by 14 | Viewed by 7615

Abstract

The widespread computer network has been changing drastically and substantially since blockchain and IoT entered the stage. Blockchain is good at protecting data transactions between logical nodes with a desirable guaranty. Internet of Things (IoT), on the other hand, by providing ultimate convenience [...] Read more.

The widespread computer network has been changing drastically and substantially since blockchain and IoT entered the stage. Blockchain is good at protecting data transactions between logical nodes with a desirable guaranty. Internet of Things (IoT), on the other hand, by providing ultimate convenience to consumers, is expected to give rise to many various merits in a broad business scene. The security of IoT is still an open problem and if blockchain can reinforce IoT security, as many authors have hoped in recent papers, these newcomers appear to make a good collaboration to reinforce IoT security. However, software copes with logical nodes and IoT involves a vast number of physical nodes (IoT devices). Enabling blockchain to protect IoT cannot be brought to reality without respectively identifying logical and physical nodes. This is identical to the Proof-of-Trust problem. In this article, we propose a conceptual solution—Blockchained IoT—and show that this concept is able to be realized on-chip level using mass-produced dynamical random access memory (DRAM). We have completed the first test of longevity and temperature dependence (−40 °C to 105 °C) to confirm the necessary characteristics for the 5G base stations that are known to have an issue of self-heating. Furthermore, we have coarsely evaluated the probability of two DRAM IC chips being associated with an identical cyber-physical chip identification accidentally. Then, such a probability is minimal. Full article

(This article belongs to the Special Issue Technologies for Industry 4.0)

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14 pages, 1828 KiB

Open AccessArticle

Evaluating Scenario-Specific Loading Processes on Mobile Phones

by Chen Zhang, Mengsha Lv, Weimin Zhang, Jun Chen, Lei Yang, Bin Lv and Tongning Wu

Technologies 2019, 7(1), 27; https://doi.org/10.3390/technologies7010027 - 1 Mar 2019

Cited by 4 | Viewed by 5505

Abstract

The manuscript presents a study that evaluates satisfaction with loading processes during human interactions with mobile devices. This is an innovative study to investigate human perception in terms of loading time for critical scenarios using a realistic mobile device. The scenarios were retrieved [...] Read more.

The manuscript presents a study that evaluates satisfaction with loading processes during human interactions with mobile devices. This is an innovative study to investigate human perception in terms of loading time for critical scenarios using a realistic mobile device. The scenarios were retrieved by internet searching. Consequently, high-fidelity models were reconstructed based on the identified scenarios. The measurements of contemporary commercial mobile devices yielded typical loading time values, which were subsequently applied in these models. Subjects operated these models, which were installed in a mobile terminal, and scored the models in terms of the loading time and processes. The results indicated that a shorter loading time was generally associated with higher scores. However, unsatisfactory scores were given to the shortest loading interval for the social App, which may indicate that users have higher expectations for this scenario. Furthermore, animation improved subjective satisfaction. These experimental protocols, the developed tools and the obtained results benefit not only manufacturers but also application developers. Full article

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8 pages, 3377 KiB

Open AccessArticle

Scissors-Type Haptic Device Using Magnetorheological Fluid Containing Iron Nanoparticles

by Mioto Waga, Yuuki Aita, Junichi Noma, Takehito Kikuchi and Yoshimune Nonomura

Technologies 2019, 7(1), 26; https://doi.org/10.3390/technologies7010026 - 27 Feb 2019

Cited by 2 | Viewed by 6360

Abstract

The mechanical ability and usefulness of simulation systems can be improved by combining a tactile display with a remote control or medical simulation systems. In this study, a scissors-type haptic device containing magnetorheological fluid (MR fluid) in its fulcrum is developed. We evaluate [...] Read more.

The mechanical ability and usefulness of simulation systems can be improved by combining a tactile display with a remote control or medical simulation systems. In this study, a scissors-type haptic device containing magnetorheological fluid (MR fluid) in its fulcrum is developed. We evaluate the mechanical response to the applied voltage and realize the presence of mechanical stimuli when a subject grasps or cuts the corresponding objects. When the magnetic field around the MR fluid is controlled by an electric voltage of 150–500 mV, the torque linearly increases from 0.007 ± 0.000 to 0.016 ± 0.000 N m. The device can provide tactile stimuli with 0.1 s of resolution. We also determined the voltage profiles based on typical force profiles obtained during grasping/cutting processes and evaluated the torque using a mechanical evaluation system. Features of the force profiles related to the soft and sticky feels were reconstructed well. Full article

(This article belongs to the Special Issue Smart Systems (SmaSys2018))

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18 pages, 2951 KiB

Open AccessArticle

Vehicular Alarm System Using mHealth Data and Lightweight Security Algorithms

by James Jin Kang, Sazia Parvin, Kiran Fahd and Sitalakshmi Venkatraman

Technologies 2019, 7(1), 25; https://doi.org/10.3390/technologies7010025 - 17 Feb 2019

Cited by 4 | Viewed by 6097

Abstract

Among the various factors affecting long distance driving are the risks imposed by a driver’s health, which could result in road accidents. Internet of Things (IoT) and mobile health (mHealth) technologies are increasingly being recognized for their role in monitoring various health parameters [...] Read more.

Among the various factors affecting long distance driving are the risks imposed by a driver’s health, which could result in road accidents. Internet of Things (IoT) and mobile health (mHealth) technologies are increasingly being recognized for their role in monitoring various health parameters of such drivers. IoT devices such as wearable devices could be used efficiently in vehicles by professional long-distance drivers. However, the adoption of such technologies is limited by security and privacy issues. This paper proposes a novel vehicular alarm notification system by integrating mHealth data of the driver with vehicular data for improving vehicle safety. The purpose of the system is to minimize road accidents by integrating the emerging mHealth technologies with the vehicular information system (VIS) using wireless body area network sensors and devices in a secure and lightweight framework. An integrated secure system could facilitate adoptability to provide timely notifications of emergencies to drivers in order to avoid road accidents and take appropriate follow-up actions. Furthermore, the information gathered by the integrated system could assist health service providers to address the driver’s root cause of potential health risks. The lightweight security framework adopted in this study is based on an efficient trust model that can improve the adoption of an mHealth integrated vehicular alarm notification system. Our contribution is to provide a real-time alarm notification service to avoid potential traffic accidents by monitoring the health status of long-distance drivers, achieved through incorporating an affordable and lightweight security system to secure health data transfer. Full article

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15 pages, 931 KiB

Open AccessArticle

Remote Health Care Provision in Care Homes in England: An Exploratory Mixed Methods Study of Yorkshire and the Humber

by Louise Newbould, Gail Mountain, Steven Ariss and Mark S. Hawley

Technologies 2019, 7(1), 24; https://doi.org/10.3390/technologies7010024 - 15 Feb 2019

Cited by 5 | Viewed by 6318

Abstract

An increasing demand for care homes in the UK, has necessitated the evaluation of innovative methods for delivering more effective health care. Videoconferencing may be one way to meet this demand. However, there is a lack of literature on the provision of videoconferencing [...] Read more.

An increasing demand for care homes in the UK, has necessitated the evaluation of innovative methods for delivering more effective health care. Videoconferencing may be one way to meet this demand. However, there is a lack of literature on the provision of videoconferencing in England. This mixed-methods study aimed to map current attitudes, knowledge and provision of videoconferencing in the Yorkshire and Humber region of England. Qualitative interviews with care home managers, a scoping review and field notes from a Special Interest Group (SIG) informed the development of a descriptive convenience survey which was sent out to care home managers in the Yorkshire and Humber region of England. The survey had a 14% (n = 124) response rate. Of those who responded, 10% (n = 12) reported using videoconferencing for health care; with over 78% (n = 97) of respondents’ care homes being based in urban areas. Approximately 62% (n = 77) of the 124 respondents had heard of videoconferencing for health care provision. Of those who reported not using videoconferencing (n = 112), 39% (n = 48) said they would consider it but would need to know more. The top ranked reason for not introducing videoconferencing was the belief that residents would not be comfortable using videoconferencing to consult with a healthcare professional. The main reason for implementation was the need for speedier access to services. Those already using videoconferencing rated videoconferencing overall as being very good (50%) (n = 6) or good (42%) (n = 5). Those who were not using it in practice appeared sceptical before implementing videoconferencing. The main driver of uptake was the home’s current access to and satisfaction with traditionally delivered health care services. Full article

(This article belongs to the Special Issue Selected Papers from AAATE2017 Congress)

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12 pages, 3257 KiB

Open AccessCommunication

Wet Relaxation of Electrospun Nanofiber Mats

by Timo Grothe, Lilia Sabantina, Michaela Klöcker, Irén Juhász Junger, Christoph Döpke and Andrea Ehrmann

Technologies 2019, 7(1), 23; https://doi.org/10.3390/technologies7010023 - 15 Feb 2019

Cited by 9 | Viewed by 6220

Abstract

Electrospinning can be used to produce nanofiber mats. One of the often used polymers for electrospinning is polyacrylonitrile (PAN), especially for the production of carbon nanofibers, but also for a diverse number of other applications. For some of these applications—e.g., creation of nano-filters—the [...] Read more.

Electrospinning can be used to produce nanofiber mats. One of the often used polymers for electrospinning is polyacrylonitrile (PAN), especially for the production of carbon nanofibers, but also for a diverse number of other applications. For some of these applications—e.g., creation of nano-filters—the dimensional stability of the nanofiber mats is crucial. While relaxation processes—especially dry, wet and washing relaxation—are well-known and often investigated for knitted fabrics, the dimensional stability of nanofiber mats has not yet been investigated. Here we report on the wet relaxation of PAN nanofiber mats, which are dependent on spinning and solution parameters such as: voltage, electrode distance, nanofiber mat thickness, and solid content in the solution. Our results show that wet relaxation has a significant effect on the samples, resulting in a dimensional change that has to be taken into account for nanofiber mats in wet applications. While the first and second soaking in pure water resulted in an increase of the nanofiber mat area up to approximately 5%, the dried sample, after the second soaking, conversely showed an area reduced by a maximum of 5%. For soaking in soap water, small areal decreases between approximately 1–4% were measured. Full article

(This article belongs to the Section Innovations in Materials Processing)

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16 pages, 1618 KiB

Open AccessArticle

Stability and Delay of NDMA-MPR Protocol in Rice-Correlated Channels with Co-Channel Interference

by Ramiro Sámano-Robles

Technologies 2019, 7(1), 22; https://doi.org/10.3390/technologies7010022 - 13 Feb 2019

Cited by 1 | Viewed by 5149

Abstract

This paper investigates backlog retransmission strategies for a class of random access protocols with retransmission diversity (i.e., network diversity multiple access or NDMA) combined with multiple-antenna-based multi-packet reception (MPR). This paper proposes NDMA-MPR as a candidate for 5G contention-based and ultra-low latency multiple [...] Read more.

This paper investigates backlog retransmission strategies for a class of random access protocols with retransmission diversity (i.e., network diversity multiple access or NDMA) combined with multiple-antenna-based multi-packet reception (MPR). This paper proposes NDMA-MPR as a candidate for 5G contention-based and ultra-low latency multiple access. This proposal is based on the following known features of NDMA-MPR: (1) near collision-free performance, (2) very low latency values, and (3) reduced feedback complexity (binary feedback). These features match the machine-type traffic, real-time, and dense object connectivity requirements in 5G. This work is an extension of previous works using a multiple antenna receiver with correlated Rice channels and co-channel interference modelled as a Rayleigh fading variable. Two backlog retransmission strategies are implemented: persistent and randomized. Boundaries and extended analysis of the system are here obtained for different network and channel conditions. Average delay is evaluated using the M/G/1 queue model with statistically independent vacations. The results suggest that NDMA-MPR can achieve very low values of latency that can guarantee real- or near-real-time performance for multiple access in 5G, even in scenarios with high correlation and moderate co-channel interference. Full article

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15 pages, 6028 KiB

Open AccessArticle

A Verifiable Fully Homomorphic Encryption Scheme for Cloud Computing Security

by Ahmed EL-YAHYAOUI and Mohamed Dafir ECH-CHERIF EL KETTANI

Technologies 2019, 7(1), 21; https://doi.org/10.3390/technologies7010021 - 6 Feb 2019

Cited by 20 | Viewed by 11137

Abstract

Performing smart computations in a context of cloud computing and big data is highly appreciated today. It allows customers to fully benefit from cloud computing capacities (such as processing or storage) without losing confidentiality of sensitive data. Fully homomorphic encryption (FHE) is a [...] Read more.

Performing smart computations in a context of cloud computing and big data is highly appreciated today. It allows customers to fully benefit from cloud computing capacities (such as processing or storage) without losing confidentiality of sensitive data. Fully homomorphic encryption (FHE) is a smart category of encryption schemes that enables working with the data in its encrypted form. It permits us to preserve confidentiality of our sensible data and to benefit from cloud computing capabilities. While FHE is combined with verifiable computation, it offers efficient procedures for outsourcing computations over encrypted data to a remote, but non-trusted, cloud server. The resulting scheme is called Verifiable Fully Homomorphic Encryption (VFHE). Currently, it has been demonstrated by many existing schemes that the theory is feasible but the efficiency needs to be dramatically improved in order to make it usable for real applications. One subtle difficulty is how to efficiently handle the noise. This paper aims to introduce an efficient and symmetric verifiable FHE based on a new mathematic structure that is noise free. In our encryption scheme, the noise is constant and does not depend on homomorphic evaluation of ciphertexts. The homomorphy of our scheme is obtained from simple matrix operations (addition and multiplication). The running time of the multiplication operation of our encryption scheme in a cloud environment has an order of a few milliseconds. Full article

(This article belongs to the Special Issue Technologies for Industry 4.0)

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14 pages, 1204 KiB

Open AccessEditor’s ChoiceArticle

Emotion Recognition from Speech Using the Bag-of-Visual Words on Audio Segment Spectrograms

by Evaggelos Spyrou, Rozalia Nikopoulou, Ioannis Vernikos and Phivos Mylonas

Technologies 2019, 7(1), 20; https://doi.org/10.3390/technologies7010020 - 4 Feb 2019

Cited by 25 | Viewed by 9194

Abstract

It is noteworthy nowadays that monitoring and understanding a human’s emotional state plays a key role in the current and forthcoming computational technologies. On the other hand, this monitoring and analysis should be as unobtrusive as possible, since in our era the digital [...] Read more.

It is noteworthy nowadays that monitoring and understanding a human’s emotional state plays a key role in the current and forthcoming computational technologies. On the other hand, this monitoring and analysis should be as unobtrusive as possible, since in our era the digital world has been smoothly adopted in everyday life activities. In this framework and within the domain of assessing humans’ affective state during their educational training, the most popular way to go is to use sensory equipment that would allow their observing without involving any kind of direct contact. Thus, in this work, we focus on human emotion recognition from audio stimuli (i.e., human speech) using a novel approach based on a computer vision inspired methodology, namely the bag-of-visual words method, applied on several audio segment spectrograms. The latter are considered to be the visual representation of the considered audio segment and may be analyzed by exploiting well-known traditional computer vision techniques, such as construction of a visual vocabulary, extraction of speeded-up robust features (SURF) features, quantization into a set of visual words, and image histogram construction. As a last step, support vector machines (SVM) classifiers are trained based on the aforementioned information. Finally, to further generalize the herein proposed approach, we utilize publicly available datasets from several human languages to perform cross-language experiments, both in terms of actor-created and real-life ones. Full article

(This article belongs to the Special Issue The PErvasive Technologies Related to Assistive Environments (PETRA))

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24 pages, 3277 KiB

Open AccessEditor’s ChoiceReview

On Distributed Denial of Service Current Defense Schemes

by Seth Djane Kotey, Eric Tutu Tchao and James Dzisi Gadze

Technologies 2019, 7(1), 19; https://doi.org/10.3390/technologies7010019 - 30 Jan 2019

Cited by 29 | Viewed by 8848

Abstract

Distributed denial of service (DDoS) attacks are a major threat to any network-based service provider. The ability of an attacker to harness the power of a lot of compromised devices to launch an attack makes it even more complex to handle. This complexity [...] Read more.

Distributed denial of service (DDoS) attacks are a major threat to any network-based service provider. The ability of an attacker to harness the power of a lot of compromised devices to launch an attack makes it even more complex to handle. This complexity can increase even more when several attackers coordinate to launch an attack on one victim. Moreover, attackers these days do not need to be highly skilled to perpetrate an attack. Tools for orchestrating an attack can easily be found online and require little to no knowledge about attack scripts to initiate an attack. Studies have been done severally to develop defense mechanisms to detect and defend against DDoS attacks. As defense schemes are designed and developed, attackers are also on the move to evade these defense mechanisms and so there is a need for a continual study in developing defense mechanisms. This paper discusses the current DDoS defense mechanisms, their strengths and weaknesses. Full article

(This article belongs to the Special Issue Technologies for Industry 4.0)

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21 pages, 5260 KiB

Open AccessArticle

Sign Language Technologies and the Critical Role of SL Resources in View of Future Internet Accessibility Services

by Eleni Efthimiou, Stavroula-Evita Fotinea, Theodore Goulas, Anna Vacalopoulou, Kiki Vasilaki and Athanasia-Lida Dimou

Technologies 2019, 7(1), 18; https://doi.org/10.3390/technologies7010018 - 29 Jan 2019

Cited by 9 | Viewed by 7465

Abstract

In this paper, we touch upon the requirement for accessibility via Sign Language as regards dynamic composition and exchange of new content in the context of natural language-based human interaction, and also the accessibility of web services and electronic content in written text [...] Read more.

In this paper, we touch upon the requirement for accessibility via Sign Language as regards dynamic composition and exchange of new content in the context of natural language-based human interaction, and also the accessibility of web services and electronic content in written text by deaf and hard-of-hearing individuals. In this framework, one key issue remains the option for composition of signed “text”, along with the ability for the reuse of pre-existing signed “text” by exploiting basic editing facilities similar to those available for written text that serve vocal language representation. An equally critical related issue is accessibility of vocal language text by born or early deaf signers, as well as the use of web-based facilities via Sign Language-supported interfaces, taking into account that the majority of native signers present limited reading skills. It is, thus, demonstrated how Sign Language technologies and resources may be integrated in human-centered applications, enabling web services and content accessibility in the education and an everyday communication context, in order to facilitate integration of signer populations in a societal environment that is strongly defined by smart life style conditions. This potential is also demonstrated by end-user-evaluation results. Full article

(This article belongs to the Special Issue The PErvasive Technologies Related to Assistive Environments (PETRA))

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20 pages, 3339 KiB

Open AccessFeature PaperArticle

Web of Things Platforms for Distance Learning Scenarios in Computer Science Disciplines: A Practical Approach

by Llanos Tobarra, Antonio Robles-Gómez, Rafael Pastor, Roberto Hernández, Jesús Cano and Daniel López

Technologies 2019, 7(1), 17; https://doi.org/10.3390/technologies7010017 - 27 Jan 2019

Cited by 10 | Viewed by 6586

Abstract

Problem-based learning is a widely used learning methodology in the field of technological disciplines, especially in distance education environments. In these environments, the most used tools, which provide learning scenarios, are remote and virtual laboratories. Internet of Things (IoT) devices can be used [...] Read more.

Problem-based learning is a widely used learning methodology in the field of technological disciplines, especially in distance education environments. In these environments, the most used tools, which provide learning scenarios, are remote and virtual laboratories. Internet of Things (IoT) devices can be used as remote or virtual laboratories. In addition to this, they can be organized/orchestrated to build remote maker spaces through the web. These types of spaces are called the Web of Things (WoT). This paper proposes the use of these types of spaces and their integration as practical activities into the curricula of technological subjects. This approach will allow us to achieve two fundamental objectives: (1) To improve the academic results (grades) of students; and (2) to increase engagement and interest of students in the studied technologies, including IoT devices. These platforms are modeled using archetypes based on different typologies and usage scenarios. In particular, these usage scenarios will implement a learning strategy for each problem to be solved. The current work shows the evolution of these archetypes and their application in the teaching of disciplines/subjects defined in computer science, such as distributed computing and cybersecurity. Full article

(This article belongs to the Special Issue Technology Advances on IoT Learning and Teaching)

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10 pages, 474 KiB

Open AccessArticle

Co-Designing the Kits of IoT Devices for Inquiry-Based Learning in STEM

by Marge Kusmin

Technologies 2019, 7(1), 16; https://doi.org/10.3390/technologies7010016 - 24 Jan 2019

Cited by 11 | Viewed by 8153

Abstract

The rapidly developing technological landscape challenges require educational institutions to constantly renew the school’s digital infrastructure in order to keep students engaged in learning difficult subjects such as Science, Technology, Engineering, and Mathematics (STEM). The Internet of Things (IoT) is one of such [...] Read more.

The rapidly developing technological landscape challenges require educational institutions to constantly renew the school’s digital infrastructure in order to keep students engaged in learning difficult subjects such as Science, Technology, Engineering, and Mathematics (STEM). The Internet of Things (IoT) is one of such new technology platforms that could help the schools enhance learning processes with innovative resources, and to increase students’ motivation to learn. This paper summarizes the first stage of a design-based research focusing on introducing IoT technologies to secondary education. Five kits of IoT devices were co-designed by researchers, teachers, and students, to optimize their match with the curricular objectives, cost, learning curve, and re-usability in various educational contexts. The study included three steps: (1) mapping out the IoT devices on the basis of the desk research, (2) literature review on STEM education practices, and (3) two focus group interviews with teachers and students from different schools. As a result of the study, five different kits of IoT devices were purchased for schools and pilot-tested in real-life settings. Full article

(This article belongs to the Special Issue Technology Advances on IoT Learning and Teaching)

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29 pages, 10715 KiB

Open AccessEditor’s ChoiceArticle

A Comprehensive Review of RFID and Bluetooth Security: Practical Analysis

by Santiago Figueroa Lorenzo, Javier Añorga Benito, Pablo García Cardarelli, Jon Alberdi Garaia and Saioa Arrizabalaga Juaristi

Technologies 2019, 7(1), 15; https://doi.org/10.3390/technologies7010015 - 24 Jan 2019

Cited by 22 | Viewed by 13864

Abstract

The Internet of Things (IoT) provides the ability to digitize physical objects into virtual data, thanks to the integration of hardware (e.g., sensors, actuators) and network communications for collecting and exchanging data. In this digitization process, however, security challenges need to be taken [...] Read more.

The Internet of Things (IoT) provides the ability to digitize physical objects into virtual data, thanks to the integration of hardware (e.g., sensors, actuators) and network communications for collecting and exchanging data. In this digitization process, however, security challenges need to be taken into account in order to prevent information availability, integrity, and confidentiality from being compromised. In this paper, security challenges of two broadly used technologies, RFID (Radio Frequency Identification) and Bluetooth, are analyzed. First, a review of the main vulnerabilities, security risk, and threats affecting both technologies are carried out. Then, open hardware and open source tools like: Proxmark3 and Ubertooth as well as BtleJuice and Bleah are used as part of the practical analysis. Lastly, risk mitigation and counter measures are proposed. Full article

(This article belongs to the Special Issue Technology Advances on IoT Learning and Teaching)

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9 pages, 1307 KiB

Open AccessArticle

An Energy Efficient Modulation Scheme for Body-Centric Terahertz (THz) Nanonetworks

by Apostolos K. Vavouris, Foteini D. Dervisi, Vasilis K. Papanikolaou, Panagiotis D. Diamantoulakis, George K. Karagiannidis and Sotirios K. Goudos

Technologies 2019, 7(1), 14; https://doi.org/10.3390/technologies7010014 - 22 Jan 2019

Cited by 4 | Viewed by 5444

Abstract

In body-centric communications, energy efficiency is a critical performance metric, while the achievable data rate is not of primary concern. In this paper we present a novel modulation scheme, which can be efficiently used in body-centric terahertz (THz) nanonetworks. The proposed scheme is [...] Read more.

In body-centric communications, energy efficiency is a critical performance metric, while the achievable data rate is not of primary concern. In this paper we present a novel modulation scheme, which can be efficiently used in body-centric terahertz (THz) nanonetworks. The proposed scheme is a combination of the time-spread On-Off keying (TS–OOK) and the pulse position modulation (PPM) and presents lower energy consumption, compared to other existing methods as TS–OOK, at a minor cost to the data rate. Furthermore, another important aspect is that the proposed modulation scheme can be effectively used to mitigate the impact of the specific kind of noise in THz body-centric communications, thus leading to better error performance. Finally, we present analytical and simulation results in order to compare the new scheme with the existing TS–OOK. Full article

(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Communications)

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16 pages, 3439 KiB

Open AccessArticle

A Telemedicine Service System Exploiting BT/BLE Wireless Sensors for Remote Management of Chronic Patients

by Massimiliano Donati, Alessio Celli, Alessio Ruiu, Sergio Saponara and Luca Fanucci

Technologies 2019, 7(1), 13; https://doi.org/10.3390/technologies7010013 - 18 Jan 2019

Cited by 30 | Viewed by 8512

Abstract

The management of the increasing number of patients affected by cardiovascular, pulmonary, and metabolic chronic diseases represents a major challenge for the National Health System (NHS) in any developed country. Chronic diseases are indeed the main cause of hospitalization, especially for elderly people, [...] Read more.

The management of the increasing number of patients affected by cardiovascular, pulmonary, and metabolic chronic diseases represents a major challenge for the National Health System (NHS) in any developed country. Chronic diseases are indeed the main cause of hospitalization, especially for elderly people, leading to sustainability problems due to the huge amount of resources required. In the last years, the adoption of the chronic care model (CCM) as assistive model improved the management of these patients and reduced the related healthcare costs. The diffusion of wireless sensors, portable devices and connectivity enables to implement new information and communication technology (ICT)-based innovative applications to further improve the outcomes of the CCM. This paper presents a telemedicine platform for data acquisition, distribution, processing, presentation, and storage, aimed to remotely monitor the clinical status of chronic patients. The proposed solution is based on monitoring kits, with wireless Bluetooth (BT)/ Bluetooth low energy (BLE) sensors and a gateway (i.e., smartphone or tablet) connected to a web-based cloud application that collects and makes available the clinical information to the medical staff. The platform allows clinicians and practitioners to monitor at distance their patients, according to personalized treatment plans, and to act promptly in case of aggravations, reducing hospitalizations and improving patients’ quality of life. Full article

(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Electronics)

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10 pages, 2062 KiB

Open AccessArticle

Perspectives on Assistive Systems for Manual Assembly Tasks in Industry

by Josef Wolfartsberger, Jean D. Hallewell Haslwanter and René Lindorfer

Technologies 2019, 7(1), 12; https://doi.org/10.3390/technologies7010012 - 16 Jan 2019

Cited by 20 | Viewed by 6585

Abstract

Small lot sizes in modern manufacturing present new challenges for people doing manual assembly tasks. Assistive systems, including context-aware instruction systems and collaborative robots, can support people to manage the increased flexibility, while also reducing the number of errors. Although there has been [...] Read more.

Small lot sizes in modern manufacturing present new challenges for people doing manual assembly tasks. Assistive systems, including context-aware instruction systems and collaborative robots, can support people to manage the increased flexibility, while also reducing the number of errors. Although there has been much research in this area, these solutions are not yet widespread in companies. This paper aims to give a better understanding of the strengths and limitations of the different technologies with respect to their practical implementation in companies, both to give insight into which technologies can be used in practice and to suggest directions for future research. The paper gives an overview of the state of the art and then describes new technological solutions designed for companies to illustrate the current status and future needs. The information provided demonstrates that, although a lot of technologies are currently being investigated and discussed, many of them are not yet at a level that they can be implemented in practice. Full article

(This article belongs to the Special Issue The PErvasive Technologies Related to Assistive Environments (PETRA))

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31 pages, 5381 KiB

Open AccessArticle

ParlAmI: A Multimodal Approach for Programming Intelligent Environments

by Evropi Stefanidi, Michalis Foukarakis, Dimitrios Arampatzis, Maria Korozi, Asterios Leonidis and Margherita Antona

Technologies 2019, 7(1), 11; https://doi.org/10.3390/technologies7010011 - 11 Jan 2019

Cited by 17 | Viewed by 8735

Abstract

The proliferation of Internet of Things (IoT) devices and services and their integration in intelligent environments creates the need for a simple yet effective way of controlling and communicating with them. Towards such a direction, this work presents ParlAmI, a conversational framework featuring [...] Read more.

The proliferation of Internet of Things (IoT) devices and services and their integration in intelligent environments creates the need for a simple yet effective way of controlling and communicating with them. Towards such a direction, this work presents ParlAmI, a conversational framework featuring a multimodal chatbot that permits users to create simple “if-then” rules to define the behavior of an intelligent environment. ParlAmI delivers a disembodied conversational agent in the form of a messaging application named MAI, and an embodied conversational agent named nAoMI employing the programmable humanoid robot NAO. This paper describes the requirements and architecture of ParlAmI, the infrastructure of the “Intelligent Home” in which ParlAmI is deployed, the characteristics and functionality of both MAI and nAoMI, and finally presents the findings of a user experience evaluation that was conducted with the participation of sixteen users. Full article

(This article belongs to the Special Issue The PErvasive Technologies Related to Assistive Environments (PETRA))

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13 pages, 1067 KiB

Open AccessEditor’s ChoiceArticle

Adapting Engineering Education to Industry 4.0 Vision

by Selim Coşkun, Yaşanur Kayıkcı and Eray Gençay

Technologies 2019, 7(1), 10; https://doi.org/10.3390/technologies7010010 - 10 Jan 2019

Cited by 134 | Viewed by 16299

Abstract

Industry 4.0 is originally a future vision described in the high-tech strategy of the German government that is conceived upon information and communication technologies like Cyber-Physical Systems, Internet of Things, Physical Internet, and Internet of Services to achieve a high degree of flexibility [...] Read more.

Industry 4.0 is originally a future vision described in the high-tech strategy of the German government that is conceived upon information and communication technologies like Cyber-Physical Systems, Internet of Things, Physical Internet, and Internet of Services to achieve a high degree of flexibility in production (individualized mass production), higher productivity rates through real-time monitoring and diagnosis, and a lower wastage rate of material in production. An important part of the tasks in the preparation for Industry 4.0 is the adaption of the higher education to the requirements of this vision, in particular the engineering education. In this work, we introduce a road map consisting of three pillars describing the changes/enhancements to be conducted in the areas of curriculum development, lab concept, and student club activities. We also report our current application of this road map at the Turkish German University, Istanbul. Full article

(This article belongs to the Special Issue Technologies for Industry 4.0)

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16 pages, 471 KiB

Open AccessFeature PaperArticle

Characterization of Fading Statistics of mmWave (28 GHz and 38 GHz) Outdoor and Indoor Radio Propagation Channels

by Sardar Muhammad Gulfam, Syed Junaid Nawaz, Konstantinos B. Baltzis, Abrar Ahmed and and Noor M. Khan

Technologies 2019, 7(1), 9; https://doi.org/10.3390/technologies7010009 - 9 Jan 2019

Cited by 4 | Viewed by 6746

Abstract

Extension of usable frequency spectrum from microwave to millimeter-wave (mmWave) is one of the key research directions in addressing the capacity demands of emerging 5th-generation communication networks. This paper presents a thorough analysis on the azimuthal multipath shape factors and second-order fading statistics [...] Read more.

Extension of usable frequency spectrum from microwave to millimeter-wave (mmWave) is one of the key research directions in addressing the capacity demands of emerging 5th-generation communication networks. This paper presents a thorough analysis on the azimuthal multipath shape factors and second-order fading statistics (SOFS) of outdoor and indoor mmWave radio propagation channels. The well-established analytical relationship of plain angular statistics of a radio propagation channel with the channel’s fading statistics is used to study the channel’s fading characteristics. The plain angle-of-arrival measurement results available in the open literature for four different outdoor radio propagation scenarios at 38 GHz, as well as nine different indoor radio propagation scenarios at 28 GHz and 38 GHz bands, are extracted by using different graphical data interpretation techniques. The considered quantifiers for energy dispersion in angular domain and SOFS are true standard-deviation, angular spread, angular constriction, and direction of maximum fading; and spatial coherence distance, spatial auto-covariance, average fade duration, and level-crossing-rate; respectively. This study focuses on the angular spread analysis only in the azimuth plane. The conducted analysis on angular spread and SOFS is of high significance in designing modulation schemes, equalization schemes, antenna-beams, channel estimation, error-correction techniques, and interleaving algorithms; for mmWave outdoor and indoor radio propagation environments. Full article

(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Communications)

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6 pages, 303 KiB

Open AccessEditorial

Acknowledgement to Reviewers of Technologies in 2018

by Technologies Editorial Office

Technologies 2019, 7(1), 8; https://doi.org/10.3390/technologies7010008 - 9 Jan 2019

Viewed by 4509

Abstract

Rigorous peer-review is the corner-stone of high-quality academic publishing [...] Full article

9 pages, 5286 KiB

Open AccessArticle

Microwave Assisted Green Synthesis of Silver Nanoparticles Using Mulberry Leaves Extract and Silver Nitrate Solution

by Le Ngoc Liem, Nguyen Phuoc The and Dieu Nguyen

Technologies 2019, 7(1), 7; https://doi.org/10.3390/technologies7010007 - 5 Jan 2019

Cited by 17 | Viewed by 7847

Abstract

In this work, silver nanoparticles (AgNPs) were synthesized quickly and in an eco-friendly manner using the extract of Mulberry leaves and aqueous solution of silver nitrate without any toxic chemicals (Yuet et al. Int. J. Nanomed. 2012, 7, 4263–4267; Krishnakuma and [...] Read more.

In this work, silver nanoparticles (AgNPs) were synthesized quickly and in an eco-friendly manner using the extract of Mulberry leaves and aqueous solution of silver nitrate without any toxic chemicals (Yuet et al. Int. J. Nanomed. 2012, 7, 4263–4267; Krishnakuma and Adavallan. Adv. Nat. Sci. Nanosci. Nanotechnol. 2014, 5, 025018). The Mulberry leaves extract functions as both a stabilizing and reducing agent. The UV-Vis spectroscopy shows a peak maximum at 430 nm. The transmission electron microscopy (TEM) image illustrated of synthesized AgNPs were nearly spherical-shaped particles whose sizes range from 15 to 20 nm. The TEM image of Nano Silver solution sample synthesized by the microwave assisted method shows nearly spherical particles, with an average particle size estimated at 10 nm. The absorption UV-vis spectrum of silver nanoparticles synthesized by the microwave assisted method (AgNPsmw) shows a sharp absorption band around 415 nm. The UV-Vis spectrum of AgNPsmw after two months of storage shows negligible peak changes of silver nanoparticles. Full article

(This article belongs to the Special Issue Reviews and Advances in Materials Processing)

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16 pages, 276 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Towards Analyzing the Complexity Landscape of Solidity Based Ethereum Smart Contracts

by Péter Hegedűs

Technologies 2019, 7(1), 6; https://doi.org/10.3390/technologies7010006 - 3 Jan 2019

Cited by 43 | Viewed by 10298

Abstract

Blockchain-based decentralized cryptocurrency platforms are currently one of the hottest topics in technology. Although most of the interest is generated by cryptocurrency related activities, it is becoming apparent that a much wider spectrum of applications can leverage the blockchain technology. The primary concepts [...] Read more.

Blockchain-based decentralized cryptocurrency platforms are currently one of the hottest topics in technology. Although most of the interest is generated by cryptocurrency related activities, it is becoming apparent that a much wider spectrum of applications can leverage the blockchain technology. The primary concepts enabling such general use of the blockchain are the so-called smart contracts, which are special programs that run on the blockchain. One of the most popular blockchain platforms that supports smart contracts is Ethereum. As smart contracts typically handle money, ensuring their low number of faults and vulnerabilities are essential. To aid smart contract developers and help to mature the technology, we need analysis tools and studies for smart contracts. As an initiative for this, we propose the adoption of some well-known OO metrics for Solidity smart contracts. Furthermore, we analyze more than 40 thousand Solidity source files with our prototype tool. The results suggest that smart contract programs are short, neither overly complex nor coupled too much, do not rely heavily on inheritance, and either quite well-commented or not commented at all. Moreover, smart contracts could benefit from an external library and dependency management mechanism, as more than 85% of the defined libraries in Solidity files code the same functionalities. Full article

(This article belongs to the Special Issue Blockchain Technology and Applications)

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29 pages, 14595 KiB

Open AccessArticle

Power Density Distribution for Laser Additive Manufacturing (SLM): Potential, Fundamentals and Advanced Applications

by Alexander S. Metel, Michael M. Stebulyanin, Sergey V. Fedorov and Anna A. Okunkova

Technologies 2019, 7(1), 5; https://doi.org/10.3390/technologies7010005 - 30 Dec 2018

Cited by 64 | Viewed by 12962

Abstract

Problems with the laser additive manufacturing of metal parts related to its low efficiency are known to hamper its development and application. The method of selective laser melting of metallic powders can be improved by the installation of an additional laser beam modulator. [...] Read more.

Problems with the laser additive manufacturing of metal parts related to its low efficiency are known to hamper its development and application. The method of selective laser melting of metallic powders can be improved by the installation of an additional laser beam modulator. This allows one to control the power density distribution optically in the laser beam, which can influence the character of heat and mass transfer in a molten pool during processing. The modulator contributes alternative modes of laser beam: Gaussian, flat top (top hat), and donut (bagel). The study of its influence includes a mathematical description and theoretical characterization of the modes, high-speed video monitoring and optical diagnostics, characterization of processing and the physical phenomena of selective laser melting, geometric characterization of single tracks, optical microscopy, and a discussion of the obtained dependences of the main selective laser melting (SLM) parameters and the field of its optimization. The single tracks were produced using the advanced technique of porosity lowering. The parameters of the obtained samples are presented in the form of 3D graphs. The further outlook and advanced applications are discussed. Full article

(This article belongs to the Special Issue Rapid Manufacturing Technologies)

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13 pages, 1852 KiB

Open AccessArticle

A High-Level Synthesis Implementation and Evaluation of an Image Processing Accelerator

by Dimitris Tsiktsiris, Dimitris Ziouzios and Minas Dasygenis

Technologies 2019, 7(1), 4; https://doi.org/10.3390/technologies7010004 - 23 Dec 2018

Cited by 11 | Viewed by 7388

Abstract

Most frequently, an FPGA is used as an implementation platform in applications of graphics processing, as its structure can effectively exploit both spatial and temporal parallelism. Such parallelization techniques involve fundamental restrictions, namely being their dependence on both the processing model and the [...] Read more.

Most frequently, an FPGA is used as an implementation platform in applications of graphics processing, as its structure can effectively exploit both spatial and temporal parallelism. Such parallelization techniques involve fundamental restrictions, namely being their dependence on both the processing model and the system’s hardware constraints, that can force the designer to restructure the architecture and the implementation. Predesigned accelerators can significantly assist the designer to solve this problem and meet his deadlines. In this paper, we present our accelerators for Grayscale and Sobel Edge Detection, two of the most fundamental algorithms used in digital image processing projects. We have implemented those algorithms with a “bare-metal” VHDL design, written purely by hand, as a portable USB accelerator device, as well as an HLS-based overlay of a similar implementation designed to be used by a Python interface. The comparisons of the two architectures showcase that the HLS generated design can perform equally to or even better than the handwritten HDL equivalent, especially when the correct compiler directives are provided. Full article

(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Electronics)

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13 pages, 3043 KiB

Open AccessArticle

Improved Parallel Legalization Schemes for Standard Cell Placement with Obstacles

by Panagiotis Oikonomou, Antonios N. Dadaliaris, Kostas Kolomvatsos, Thanasis Loukopoulos, Athanasios Kakarountas and Georgios I. Stamoulis

Technologies 2019, 7(1), 3; https://doi.org/10.3390/technologies7010003 - 22 Dec 2018

Viewed by 5535

Abstract

In standard cell placement, a circuit is given consisting of cells with a standard height, (different widths) and the problem is to place the cells in the standard rows of a chip area so that no overlaps occur and some target function is [...] Read more.

In standard cell placement, a circuit is given consisting of cells with a standard height, (different widths) and the problem is to place the cells in the standard rows of a chip area so that no overlaps occur and some target function is optimized. The process is usually split into at least two phases. In a first pass, a global placement algorithm distributes the cells across the circuit area, while in the second step, a legalization algorithm aligns the cells to the standard rows of the power grid and alleviates any overlaps. While a few legalization schemes have been proposed in the past for the basic problem formulation, few obstacle-aware extensions exist. Furthermore, they usually provide extreme trade-offs between time performance and optimization efficiency. In this paper, we focus on the legalization step, in the presence of pre-allocated modules acting as obstacles. We extend two known algorithmic approaches, namely Tetris and Abacus, so that they become obstacle-aware. Furthermore, we propose a parallelization scheme to tackle the computational complexity. The experiments illustrate that the proposed parallelization method achieves a good scalability, while it also efficiently prunes the search space resulting in a superlinear speedup. Furthermore, this time performance comes at only a small cost (sometimes even improvement) concerning the typical optimization metrics. Full article

(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Electronics)

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17 pages, 2938 KiB

Open AccessArticle

RabbitRun: An Immersive Virtual Reality Game for Promoting Physical Activities Among People with Low Back Pain

by Amal Alazba, Hend Al-Khalifa and Hana AlSobayel

Technologies 2019, 7(1), 2; https://doi.org/10.3390/technologies7010002 - 20 Dec 2018

Cited by 14 | Viewed by 8248

Abstract

Low back pain (LBP) is one of the most common problems among adults. The usual physiotherapy treatment is to perform physical exercises. However, some LBP patients have false beliefs regarding their pain and they tend to avoid physical movements which might increase their [...] Read more.

Low back pain (LBP) is one of the most common problems among adults. The usual physiotherapy treatment is to perform physical exercises. However, some LBP patients have false beliefs regarding their pain and they tend to avoid physical movements which might increase their pain and disability. Virtual reality (VR) has proven to be an effective intervention in improving motor functions and reducing pain perception. Existing VR interventions for LBP rehabilitation were based on a non-immersive VR, whereas to effectively reduce the pain intensity, we need an immersive VR. In this paper, we introduce the development and evaluation of a serious game called RabbitRun with an immersive experience to engage the patients in a virtual environment and distract them from the pain while performing LBP exercises. The initial usability evaluation results suggest that RabbitRun game is enjoyable and acceptable. The game is easy to play and learn and most of the participants are willing to play the game at home. This solution will enhance the rehabilitation outcome since the patients who are suffering from LBP can use the system at their home and train more for long period of time using a smartphone and low-cost virtual reality device, such as Google Cardboard. Full article

(This article belongs to the Special Issue The PErvasive Technologies Related to Assistive Environments (PETRA))

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15 pages, 687 KiB

Open AccessFeature PaperArticle

A Preconditioned Iterative Approach for Efficient Full Chip Thermal Analysis on Massively Parallel Platforms

by George Floros, Konstantis Daloukas, Nestor Evmorfopoulos and George Stamoulis

Technologies 2019, 7(1), 1; https://doi.org/10.3390/technologies7010001 - 20 Dec 2018

Cited by 2 | Viewed by 5341

Abstract

Efficient full-chip thermal simulation is among the most challenging problems facing the EDA industry today, especially for modern 3D integrated circuits, due to the huge linear systems resulting from thermal modeling approaches that require unreasonably long computational times. While the formulation problem, by [...] Read more.

Efficient full-chip thermal simulation is among the most challenging problems facing the EDA industry today, especially for modern 3D integrated circuits, due to the huge linear systems resulting from thermal modeling approaches that require unreasonably long computational times. While the formulation problem, by applying a thermal equivalent circuit, is prevalent and can be easily constructed, the corresponding 3D equations network has an undesirable time-consuming numerical simulation. Direct linear solvers are not capable of handling such huge problems, and iterative methods are the only feasible approach. In this paper, we propose a computationally-efficient iterative method with a parallel preconditioned technique that exploits the resources of massively-parallel architectures such as Graphic Processor Units (GPUs). Experimental results demonstrate that the proposed method achieves a speedup of 2.2× in CPU execution and a 26.93× speedup in GPU execution over the state-of-the-art iterative method. Full article

(This article belongs to the Special Issue Modern Circuits and Systems Technologies on Electronics)

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Technologies, Volume 7, Issue 1 (March 2019) – 29 articles

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