Technologies

13 pages, 2111 KB

Open AccessArticle

Elderly in the Digital Era. Theoretical Perspectives on Assistive Technologies

by Ioana Iancu and Bogdan Iancu

Technologies 2017, 5(3), 60; https://doi.org/10.3390/technologies5030060 - 15 Sep 2017

Cited by 48 | Viewed by 12698

The present paper presents a theoretical perspective on assistive technology for elderly people. In a context characterized by an aging population and an increased life expectancy, it is highly likely that we will become the spectators of a powerful pressure on the medical [...] Read more.

The present paper presents a theoretical perspective on assistive technology for elderly people. In a context characterized by an aging population and an increased life expectancy, it is highly likely that we will become the spectators of a powerful pressure on the medical assistance process. An increasing life expectancy means an increasing need of assistance for longer periods of time, which might become an unfeasible and unrealistic policy due to limited medical resources. In this context, assistive technology might become the only solution. Starting from an international context, this paper aims to theoretically present the way technology can be used as a tool for the elderly’s needs. Full article

(This article belongs to the Section Assistive Technologies)

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17 pages, 958 KB

Open AccessArticle

Effect of AQM-Based RLC Buffer Management on the eNB Scheduling Algorithm in LTE Network

by Anup Kumar Paul, Hidehiko Kawakami, Atsuo Tachibana and Teruyuki Hasegawa

Technologies 2017, 5(3), 59; https://doi.org/10.3390/technologies5030059 - 14 Sep 2017

Cited by 14 | Viewed by 8657

Abstract

With the advancement of the Long-Term Evolution (LTE) network and smart-phones, most of today’s internet content is delivered via cellular links. Due to the nature of wireless signal propagation, the capacity of the last hop link can vary within a short period of [...] Read more.

With the advancement of the Long-Term Evolution (LTE) network and smart-phones, most of today’s internet content is delivered via cellular links. Due to the nature of wireless signal propagation, the capacity of the last hop link can vary within a short period of time. Unfortunately, Transmission Control Protocol (TCP) does not perform well in such scenarios, potentially leading to poor Quality of Service (QoS) (e.g., end-to-end throughput and delay) for the end user. In this work, we have studied the effect of Active Queue Management (AQM) based congestion control and intra LTE handover on the performance of different Medium Access Control (MAC) schedulers with TCP traffic by ns3 simulation. A proper AQM design in the Radio Link Control (RLC) buffer of eNB in the LTE network leads to the avoidance of forced drops and link under-utilization along with robustness to a variety of network traffic-loads. We first demonstrate that the original Random Early Detection (RED) linear dropping function cannot cope well with different traffic-load scenarios. Then, we establish a heuristic approach in which different non-linear functions are proposed with one parameter free to define. In our simulations, we demonstrate that the performance of different schedulers can be enhanced via proper dropping function. Full article

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2 pages, 144 KB

Open AccessEditorial

Special Issue on “Additive Manufacturing Technologies and Applications”

by Salvatore Brischetto, Paolo Maggiore and Carlo Giovanni Ferro

Technologies 2017, 5(3), 58; https://doi.org/10.3390/technologies5030058 - 12 Sep 2017

Cited by 12 | Viewed by 6187

Abstract

Additive Manufacturing (AM) is a well-known technology, first patented in 1984 by the French scientist Alain Le Mehaute [...]
Full article

(This article belongs to the Special Issue Additive Manufacturing Technologies and Applications)

26 pages, 333 KB

Open AccessTechnical Note

Semiclassical Length Measure from a Quantum-Gravity Wave Function

by Orchidea Maria Lecian

Technologies 2017, 5(3), 56; https://doi.org/10.3390/technologies5030056 - 8 Sep 2017

Viewed by 5103

Abstract

The definition of a length operator in quantum cosmology is usually influenced by a quantum theory for gravity considered. The semiclassical limit at the Planck age must meet the requirements implied in present observations. The features of a semiclassical wave-functional state are investigated, [...] Read more.

The definition of a length operator in quantum cosmology is usually influenced by a quantum theory for gravity considered. The semiclassical limit at the Planck age must meet the requirements implied in present observations. The features of a semiclassical wave-functional state are investigated, for which the modern measure(ment)s is consistent. The results of a length measurement at present times are compared with the same measurement operation at cosmological times. By this measure, it is possible to discriminate, within the same Planck-length expansion, the corrections to a Minkowski flat space possibly due to classicalization of quantum phenomena at the Planck time and those due to possible quantum-gravitational manifestations of present times. This analysis and the comparison with the previous literature can be framed as a test for the verification of the time at which anomalies at present related to the gravitational field, and, in particular, whether they are ascribed to the classicalization epoch. Indeed, it allows to discriminate not only within the possible quantum features of the quasi (Minkowski) flat spacetime, but also from (possibly Lorentz violating) phenomena detectable at high-energy astrophysical scales. The results of two different (coordinate) length measures have been compared both at cosmological time and as a perturbation element on flat Minkowski spacetime. The differences for the components of the corresponding classical(ized) metric tensor have been analyzed at different orders of expansions. The results of the expectation values of a length operator in the universe at the Planck time must be comparable with the same length measurements at present times, as far as the metric tensor is concerned. The comparison of the results of (straight) length measures in two different directions, in particular, can encode the pertinent information about the parameters defining the semiclassical wavefunctional for (semiclassicalized) gravitational field. Full article

(This article belongs to the Special Issue Quantum Gravity Phenomenology and Experimental Implications)

10 pages, 2767 KB

Open AccessArticle

Characterising the Physical, Phytochemical and Antioxidant Properties of the Tuckeroo (Cupaniopsis anacardioides) Fruit

by Ngoc Minh Quynh Pham, Anita C. Chalmers, Quan V. Vuong, Michael C. Bowyer and Christopher J. Scarlett

Technologies 2017, 5(3), 57; https://doi.org/10.3390/technologies5030057 - 6 Sep 2017

Cited by 8 | Viewed by 14980

Abstract

The tuckeroo (Cupaniopsis anacardioides) is an Australian native plant that fruits over the summer months. There are very few studies that have characterised its fruit; consequently, this study aimed to delineate the physical, phytochemical and antioxidant properties of the tuckeroo fruit. [...] Read more.

The tuckeroo (Cupaniopsis anacardioides) is an Australian native plant that fruits over the summer months. There are very few studies that have characterised its fruit; consequently, this study aimed to delineate the physical, phytochemical and antioxidant properties of the tuckeroo fruit. The tuckeroo skin embodied the largest weight proportion with over 77% of the total fruit weight and it had the highest levels of total phenolic compounds (TPC; 151.36 mg GAE/g), total flavonoids compounds (TFC; 95.94 mg CAE/g), and proanthocyanidins (Proanth; 164.86 mg CAE/g) content, as well as the strongest antioxidant power. The seed and flesh accounted for 23% of the total fruit weight and they possessed significantly lower levels of TPC, TFC and Proanth. This study has demonstrated that the tuckeroo fruit skin is a rich source of phenolic compounds, which can be further isolated and identified for further utilisation in the food and pharmaceutical industries. Full article

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8 pages, 667 KB

Open AccessArticle

Sample Entropy Identifies Differences in Spontaneous Leg Movement Behavior between Infants with Typical Development and Infants at Risk of Developmental Delay

by Beth A. Smith, Douglas L. Vanderbilt, Bryon Applequist and Anastasia Kyvelidou

Technologies 2017, 5(3), 55; https://doi.org/10.3390/technologies5030055 - 2 Sep 2017

Cited by 30 | Viewed by 5986

Abstract

We are interested in using wearable sensor data to analyze detailed characteristics of movement, such as repeatability and variability of movement patterns, over days and months to accurately capture real-world infant behavior. The purpose of this study was to explore Sample Entropy (SampEn) [...] Read more.

We are interested in using wearable sensor data to analyze detailed characteristics of movement, such as repeatability and variability of movement patterns, over days and months to accurately capture real-world infant behavior. The purpose of this study was to explore Sample Entropy (SampEn) from wearable sensor data as a measure of variability of spontaneous infant leg movement and as a potential marker of the development of neuromotor control. We hypothesized that infants at risk (AR) of developmental delay would present significantly lower SampEn values than infants with typical development (TD). Participants were 11 infants with TD and 20 infants AR. We calculated SampEn from 1–4 periods of data of 7200 samples in length when the infants were actively playing across the day. The infants AR demonstrated smaller SampEn values (median 0.21) than the infants with TD (median 1.20). Lower values of SampEn indicate more similarity in patterns across time, and may indicate more repetitive, less exploratory behavior in infants AR compared to infants with TD. In future studies, we would like to expand to analyze longer periods of wearable sensor data and/or determine how to optimally sample representative periods across days and months. Full article

(This article belongs to the Special Issue Personal Health and Wellbeing Intelligent Systems Based on Wearable and Mobile Technologies)

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13 pages, 969 KB

Open AccessArticle

A Conceptual Framework for Implementing a WSN Based Cattle Recovery System in Case of Cattle Rustling in Kenya

by Patrick Kanyi Wamuyu

Technologies 2017, 5(3), 54; https://doi.org/10.3390/technologies5030054 - 31 Aug 2017

Cited by 13 | Viewed by 8069

Abstract

This study proposes a framework for remote identification and tracking of cattle movement based on wireless sensor networks (WSN), mobile communication, and unmanned aerial vehicles (UAVs). The proposed framework can be implemented for tracking cattle movement at the village level and extended to [...] Read more.

This study proposes a framework for remote identification and tracking of cattle movement based on wireless sensor networks (WSN), mobile communication, and unmanned aerial vehicles (UAVs). The proposed framework can be implemented for tracking cattle movement at the village level and extended to harsh terrain when recovering stolen animals in case of cattle rustling or theft. The system works by identifying and tracking the desired animal location and sending periodic location data at regular intervals to a database as well as availing the specific animal’s current location on demand through the Internet and text messages. The proposed cattle tracking and recovery system (CTRS) consists of a rumen sensor module, a WSN control unit, a Worldwide Interoperability for Microwave Access (WiMAX) gateway, WiMAX base stations, and a data center. Availing timely information about the location of the stolen animals could facilitate quick recovery of the animals while ensuring the safety of the security personnel involved in the recovery process. Speedy recovery of stolen animals also defeats the purpose of cattle rustling as the rustlers do not have the chance to use the animals for their intended purposes. The proposed system was tested through a MATLAB simulation experiment. Full article

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18 pages, 1587 KB

Open AccessReview

Organic Solar Cell by Inkjet Printing—An Overview

by Sharaf Sumaiya, Kamran Kardel and Adel El-Shahat

Technologies 2017, 5(3), 53; https://doi.org/10.3390/technologies5030053 - 24 Aug 2017

Cited by 59 | Viewed by 11945

Abstract

In recent years, organic solar cells became more attractive due to their flexible power devices and the potential for low-cost manufacturing. Inkjet printing is a very potential manufacturing technique of organic solar cells because of its low material usage, flexibility, and large area [...] Read more.

In recent years, organic solar cells became more attractive due to their flexible power devices and the potential for low-cost manufacturing. Inkjet printing is a very potential manufacturing technique of organic solar cells because of its low material usage, flexibility, and large area formation. In this paper, we presented an overall review on the inkjet printing technology as well as advantages of inkjet-printing, comparison of inkjet printing with other printing technologies and its potential for organic solar cells (OSCs). Here we highlighted in more details about the viability of environment-friendly and cost-effective, non-halogenated indium tin oxide (ITO) free large scale roll to roll production of the OSC by inkjet printing technology. The challenges of inkjet printing like the viscosity limitations, nozzle clogging, coffee ring effect, and limitation of printability as well as dot spacing are also discussed. Lastly, some of the improvement strategies for getting the higher efficiency of the OSCs have been suggested. Full article

(This article belongs to the Section Environmental Technology)

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11 pages, 4569 KB

Open AccessArticle

Teaching Enzyme Activity to the Visual Impaired and Blind Students

by Felipe Sales De Oliveira, Agatha Santos do Nascimento and Maria Lucia Bianconi

Technologies 2017, 5(3), 52; https://doi.org/10.3390/technologies5030052 - 17 Aug 2017

Cited by 5 | Viewed by 6822

Abstract

Biochemistry requires a high abstraction level, and different approaches should be used to enable the proper understanding of different subjects. In particular, students with visual impairment or blindness need special attention, not due to a lack of cognitive skills, but due to the [...] Read more.

Biochemistry requires a high abstraction level, and different approaches should be used to enable the proper understanding of different subjects. In particular, students with visual impairment or blindness need special attention, not due to a lack of cognitive skills, but due to the fact that most of the teaching methods are visual. Enzyme properties are usually taught through experimental data that show how the activity changes in different conditions, which end up with the analysis of graphs. Therefore, our group developed experiments and graphical representations that enable visually impaired and blind students to understand enzyme properties. The experiments were done with pineapple bromelain, using reconstituted dry milk and gelatin as substrates. The “visualization” of the results were based on the sensation of the viscosity of the samples. The graphs were made with cold porcelain with all the labels (legends and numbers) written in Braille with a positive slate. From our experience with a blind student, both the experiments and the graphic representations were useful adaptations for teaching enzyme properties. Full article

(This article belongs to the Special Issue Education Technologies)

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14 pages, 224 KB

Open AccessArticle

A Conceptual Test for Cognitively Coherent Quantum Gravity Models

by Simonluca Pinna and Simone Pinna

Technologies 2017, 5(3), 51; https://doi.org/10.3390/technologies5030051 - 15 Aug 2017

Viewed by 4632

Abstract

In quantum gravity interpretations, the role of space- and time-related concepts is debated. Some argue that these concepts are not needed to describe physical reality at the Planck scale. Others object that an operational definition of magnitudes cannot get rid of spatiotemporal notions. [...] Read more.

In quantum gravity interpretations, the role of space- and time-related concepts is debated. Some argue that these concepts are not needed to describe physical reality at the Planck scale. Others object that an operational definition of magnitudes cannot get rid of spatiotemporal notions. We propose a “conceptual test” to assess if the mathematical content of a quantum gravity theory refers to some possibly verifiable empirical model. Given that any physical model describes the evolution of a set of measurables, these must be detectable in any empirical interpretation of a physical theory, including quantum gravity ones. Our test ultimately relies on considerations and studies concerning human cognitive limits in the discrimination of magnitudes. Full article

(This article belongs to the Special Issue Quantum Gravity Phenomenology and Experimental Implications)

13 pages, 8555 KB

Open AccessArticle

Paste Extruder—Hardware Add-On for Desktop 3D Printers

by Catalin Gheorghe Amza, Aurelian Zapciu and Diana Popescu

Technologies 2017, 5(3), 50; https://doi.org/10.3390/technologies5030050 - 8 Aug 2017

Cited by 24 | Viewed by 18724

Abstract

This paper presents the design, development and testing of a paste/clay extrusion device intended to be used as a drop-in replacement for the conventional thermoplastic extruder of a desktop filament-based 3D printer. A plastic cylinder loaded with gel, paste or clay material is [...] Read more.

This paper presents the design, development and testing of a paste/clay extrusion device intended to be used as a drop-in replacement for the conventional thermoplastic extruder of a desktop filament-based 3D printer. A plastic cylinder loaded with gel, paste or clay material is placed into the device. Feedstock is pressed through an extrusion nozzle by a piston driven by an electrically actuated drive-screw and nut mechanism. The device allows the build material to heat up to 80 °C. Forced air cooling is used to assist the cooling or hardening process of the freshly-printed material during fabrication. The feedstock container, nozzle, and material-loading process are all suitable for use in a sterile environment. The device is designed for seamless integration with existing 3D printing firmware and slicing software. After designing the device, a prototype was produced and installed on a 3D printer. Silicone and acrylic polymers, as well as dental gel, were used to fabricate 3D printed sample objects. Full article

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11 pages, 1304 KB

Open AccessArticle

A Low-Cost, Wearable Opto-Inertial 6-DOF Hand Pose Tracking System for VR

by Andualem T. Maereg, Emanuele L. Secco, Tayachew F. Agidew, David Reid and Atulya K. Nagar

Technologies 2017, 5(3), 49; https://doi.org/10.3390/technologies5030049 - 28 Jul 2017

Cited by 13 | Viewed by 11154

Abstract

In this paper, a low cost, wearable six Degree of Freedom (6-DOF) hand pose tracking system is proposed for Virtual Reality applications. It is designed for use with an integrated hand exoskeleton system for kinesthetic haptic feedback. The tracking system consists of an [...] Read more.

In this paper, a low cost, wearable six Degree of Freedom (6-DOF) hand pose tracking system is proposed for Virtual Reality applications. It is designed for use with an integrated hand exoskeleton system for kinesthetic haptic feedback. The tracking system consists of an Infrared (IR) based optical tracker with low cost mono-camera and inertial and magnetic measurement unit. Image processing is done on LabVIEW software to extract the 3-DOF position from two IR targets and Magdwick filter has been implemented on Mbed LPC1768 board to obtain orientation data. Six DOF hand tracking outputs filtered and synchronized on LabVIEW software are then sent to the Unity Virtual environment via User Datagram Protocol (UDP) stream. Experimental results show that this low cost and compact system has a comparable performance of minimal Jitter with position and orientation Root Mean Square Error (RMSE) of less than 0.2 mm and 0.15 degrees, respectively. Total Latency of the system is also less than 40 ms. Full article

(This article belongs to the Special Issue Wearable Technologies)

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10 pages, 8301 KB

Open AccessArticle

Development of a High-Speed Current Injection and Voltage Measurement System for Electrical Impedance Tomography-Based Stretchable Sensors

by Stefania Russo, Samia Nefti-Meziani, Nicola Carbonaro and Alessandro Tognetti

Technologies 2017, 5(3), 48; https://doi.org/10.3390/technologies5030048 - 26 Jul 2017

Cited by 24 | Viewed by 9903

Abstract

Electrical impedance tomography (EIT) is an imaging method that can be applied over stretchable conductive-fabric materials to realize soft and wearable pressure sensors through current injections and voltage measurements at electrodes placed at the boundary of a conductive medium. In common EIT systems, [...] Read more.

Electrical impedance tomography (EIT) is an imaging method that can be applied over stretchable conductive-fabric materials to realize soft and wearable pressure sensors through current injections and voltage measurements at electrodes placed at the boundary of a conductive medium. In common EIT systems, the voltage data are serially measured by means of multiplexers, and are hence collected at slightly different times, which affects the real-time performance of the system. They also tend to have complicated hardware, which increases power consumption. In this paper, we present our design of a 16-electrode high-speed EIT system that simultaneously implements constant current injection and differential potential measurements. This leads to a faster, simpler-to-implement and less-noisy technique, when compared with traditional EIT approaches. Our system consists of a Howland current pump with two multiplexers for a constant DC current supply, and a data acquisition card. It guarantees a data collection rate of 78 frames/s. The results from our conductive stretchable fabric sensor show that the system successfully performs voltage data collection with a mean signal-to-noise ratio (SNR) of 55 dB, and a mean absolute deviation (MAD) of 0.5 mV. The power consumption can be brought down to 3 mW; therefore, it is suitable for battery-powered applications. Finally, pressure contacts over the sensor are properly reconstructed, thereby validating the efficiency of our EIT system for soft and stretchable sensor applications. Full article

(This article belongs to the Special Issue Wearable Technologies)

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14 pages, 3834 KB

Open AccessArticle

Determining the Reliability of Several Consumer-Based Physical Activity Monitors

by Joshua M. Bock, Leonard A. Kaminsky, Matthew P. Harber and Alexander H. K. Montoye

Technologies 2017, 5(3), 47; https://doi.org/10.3390/technologies5030047 - 24 Jul 2017

Cited by 5 | Viewed by 6461

Abstract

Limited research exists on the reliability of consumer-based physical activity monitors (CPAMs) despite numerous studies on their validity. Consumers often purchase CPAMs to assess their physical activity (PA) habits over time, emphasizing CPAM reliability more so than their validity; therefore, the purpose of [...] Read more.

Limited research exists on the reliability of consumer-based physical activity monitors (CPAMs) despite numerous studies on their validity. Consumers often purchase CPAMs to assess their physical activity (PA) habits over time, emphasizing CPAM reliability more so than their validity; therefore, the purpose of this study was to investigate the reliability of several CPAMs. In this study, 30 participants wore a pair of four CPAM models (Fitbit One, Zip, Flex, and Jawbone Up24) for a total of eight monitors, while completing seven activities in the laboratory. Activities were completed in two consecutive five-minute bouts. Participants then wore either all wrist- or hip-mounted CPAMs in a free-living setting for the remainder of the day. Intra-monitor reliability for steps (0.88–0.99) was higher than kcals (0.77–0.94), and was higher for hip-worn CPAMs than for wrist-worn CPAMs (p < 0.001 for both). Inter-monitor reliability in the laboratory for steps (0.81–0.99) was higher than kcals (0.64–0.91) and higher for hip-worn CPAMs than for wrist-worn CPAMs (p < 0.001 for both). Free-living correlations were 0.61–0.98, 0.35–0.96, and 0.97–0.98 for steps, kcals, and active minutes, respectively. These findings illustrate that all CPAMs assessed yield reliable estimations of PA. Additionally, all CPAMs tested can provide reliable estimations of physical activity within the laboratory but appear less reliable in a free-living setting. Full article

(This article belongs to the Special Issue Wearable Technologies)

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22 pages, 4429 KB

Open AccessFeature PaperArticle

Impact of DIY Home Manufacturing with 3D Printing on the Toy and Game Market

by Emily E. Petersen, Romain W. Kidd and Joshua M. Pearce

Technologies 2017, 5(3), 45; https://doi.org/10.3390/technologies5030045 - 20 Jul 2017

Cited by 75 | Viewed by 30960

Abstract

The 2020 toy and game market is projected to be US$135 billion. To determine if 3D printing could affect these markets if consumers offset purchases by 3D printing free designs, this study investigates the 100 most popular downloaded designs at MyMiniFactory in a [...] Read more.

The 2020 toy and game market is projected to be US$135 billion. To determine if 3D printing could affect these markets if consumers offset purchases by 3D printing free designs, this study investigates the 100 most popular downloaded designs at MyMiniFactory in a month. Savings are quantified for using a Lulzbot Mini 3D printer and three filament types: commercial filament, pellet-extruded filament, and post-consumer waste converted to filament with a recyclebot. Case studies probed the quality of: (1) six common complex toys; (2) Lego blocks; and (3) the customizability of open source board games. All filaments analyzed saved the user over 75% of the cost of commercially available true alternative toys and over 90% for recyclebot filament. Overall, these results indicate a single 3D printing repository among dozens is saving consumers well over $60 million/year in offset purchases. The most common savings fell by 40%–90% in total savings, which came with the ability to make novel toys and games. The results of this study show consumers can generate higher value items for less money using the open source distributed manufacturing paradigm. It appears clear that consumer do-it-yourself (DIY) manufacturing is set to have a significant impact on the toy and game markets in the future. Full article

(This article belongs to the Special Issue Additive Manufacturing Technologies and Applications)

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16 pages, 3094 KB

Open AccessArticle

DC Model Cable under Polarity Inversion and Thermal Gradient: Build-Up of Design-Related Space Charge

by Nugroho Adi, Thi Thu Nga Vu, Gilbert Teyssèdre, Fulbert Baudoin and Ngapuli Sinisuka

Technologies 2017, 5(3), 46; https://doi.org/10.3390/technologies5030046 - 17 Jul 2017

Cited by 26 | Viewed by 7794

Abstract

In the field of energy transport, High-Voltage DC (HVDC) technologies are booming at present due to the more flexible power converter solutions along with needs to bring electrical energy from distributed production areas to consumption sites and to strengthen large-scale energy networks. These [...] Read more.

In the field of energy transport, High-Voltage DC (HVDC) technologies are booming at present due to the more flexible power converter solutions along with needs to bring electrical energy from distributed production areas to consumption sites and to strengthen large-scale energy networks. These developments go with challenges in qualifying insulating materials embedded in those systems and in the design of insulations relying on stress distribution. Our purpose in this communication is to illustrate how far the field distribution in DC insulation systems can be anticipated based on conductivity data gathered as a function of temperature and electric field. Transient currents and conductivity estimates as a function of temperature and field were recorded on miniaturized HVDC power cables with construction of 1.5 mm thick crosslinked polyethylene (XLPE) insulation. Outputs of the conductivity model are compared to measured field distributions using space charge measurements techniques. It is shown that some features of the field distribution on model cables put under thermal gradient can be anticipated based on conductivity data. However, space charge build-up can induce substantial electric field strengthening when materials are not well controlled. Full article

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

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12 pages, 2434 KB

Open AccessArticle

Validation of the HUMAC Balance System in Comparison with Conventional Force Plates

by Jan Jens Koltermann, Martin Gerber, Heidrun Beck and Michael Beck

Technologies 2017, 5(3), 44; https://doi.org/10.3390/technologies5030044 - 14 Jul 2017

Cited by 38 | Viewed by 10781

Abstract

In recent years, there has been intensified development of cost-effective alternatives to conventional force plates, such as those of Kistler and AMTI, in clinical and scientific research. To our knowledge, the evidence for existing validity and reliability of the HUMAC Balance System has [...] Read more.

In recent years, there has been intensified development of cost-effective alternatives to conventional force plates, such as those of Kistler and AMTI, in clinical and scientific research. To our knowledge, the evidence for existing validity and reliability of the HUMAC Balance System has so far been lacking. Over the course of the study, the HUMAC Balance System, which is based on the WII Balance Board technology, was tested. 26 HUMAC Balance Systems in conjunction with 2 force plates, each from the manufacturers Kistler and AMTI, were examined and their properties under static and dynamic conditions were evaluated. Under static conditions, the HUMAC Balance System revealed a relatively constant and comparatively small margin of displacement error. However, tests of the force plates under dynamic conditions revealed contrasting results. The conventional force plates, with a margin of error of 2.5%, proved to have a smaller margin of error compared to the HUMAC Balance System, which had margins of error of 8.6% and 6.1% in x and y directions, respectively. A calibration method was developed to overcome these systematic deviations. After applying the calibration, the Balance Board margin of error was reduced to an acceptable maximum of 0.18%. Full article

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18 pages, 2727 KB

Open AccessArticle

Communication Challenges in on-Body and Body-to-Body Wearable Wireless Networks—A Connectivity Perspective

by Dhafer Ben Arbia, Muhammad Mahtab Alam, Yannick Le Moullec and Elyes Ben Hamida

Technologies 2017, 5(3), 43; https://doi.org/10.3390/technologies5030043 - 6 Jul 2017

Cited by 28 | Viewed by 12085

Abstract

Wearable wireless networks (WWNs) offer innovative ways to connect humans and/or objects anywhere, anytime, within an infinite variety of applications. WWNs include three levels of communications: on-body, body-to-body and off-body communication. Successful communication in on-body and body-to-body networks is often challenging due to [...] Read more.

Wearable wireless networks (WWNs) offer innovative ways to connect humans and/or objects anywhere, anytime, within an infinite variety of applications. WWNs include three levels of communications: on-body, body-to-body and off-body communication. Successful communication in on-body and body-to-body networks is often challenging due to ultra-low power consumption, processing and storage capabilities, which have a significant impact on the achievable throughput and packet reception ratio as well as latency. Consequently, all these factors make it difficult to opt for an appropriate technology to optimize communication performance, which predominantly depends on the given application. In particular, this work emphasizes the impact of coarse-grain factors (such as dynamic and diverse mobility, radio-link and signal propagation, interference management, data dissemination schemes, and routing approaches) directly affecting the communication performance in WWNs. Experiments have been performed on a real testbed to investigate the connectivity behavior on two wireless communication levels: on-body and body-to-body. It is concluded that by considering the impact of above-mentioned factors, the general perception of using specific technologies may not be correct. Indeed, for on-body communication, by using the IEEE 802.15.6 standard (which is specifically designed for on-body communication), it is observed that while operating at low transmission power under realistic conditions, the connectivity can be significantly low, thus, the transmission power has to be tuned carefully. Similarly, for body-to-body communication in an indoor environment, WiFi IEEE 802.11n also has a high threshold of end-to-end disconnections beyond two hops (approximatively 25 m). Therefore, these facts promote the use of novel technologies such as 802.11ac, NarrowBand-IoT (NB-IoT) etc. as possible candidates for body-to-body communications as a part of the Internet of humans concept. Full article

(This article belongs to the Special Issue Wearable Technologies)

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13 pages, 3412 KB

Open AccessArticle

Energy Efficiency in the Microwave-Assisted Solid-State Synthesis of Cobalt Aluminate Pigment

by Paolo Veronesi, Cristina Leonelli and Federica Bondioli

Technologies 2017, 5(3), 42; https://doi.org/10.3390/technologies5030042 - 4 Jul 2017

Cited by 20 | Viewed by 7295

Abstract

Abstract: Due to their rapid, selective, and volumetric heating, microwaves have been widely used in the past to enhance solid-state reactions as well as the synthesis of ceramic pigments. The aim of this work is to present a case study involving the [...] Read more.

Abstract: Due to their rapid, selective, and volumetric heating, microwaves have been widely used in the past to enhance solid-state reactions as well as the synthesis of ceramic pigments. The aim of this work is to present a case study involving the preparation of blue CoAl₂O₄ pigment using different microwave applicators and generator frequencies, showing the advantages which can derive from a properly designed microwave reactor for the solid-state synthesis of such pigment. The results show that, when using a properly designed microwave applicator, the specific energy consumption can be significantly lowered compared to conventional heating techniques. Consistently with the data on the dielectric properties of precursors found in literature, the microwave processing of cobalt oxide and aluminum hydroxide mixtures resulted more favorable at 2.45 GHz than at 5.8 GHz microwave frequency. Full article

(This article belongs to the Special Issue Ceramic Technologies and Applications)

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13 pages, 4152 KB

Open AccessArticle

Feasibility Study of a Table Prototype Made of High-Performance Fiber-Reinforced Concrete

by Elisa Baioni, Roberto Alessi, Valeria Corinaldesi, Giovanni Lancioni and Robin Rizzini

Technologies 2017, 5(3), 41; https://doi.org/10.3390/technologies5030041 - 4 Jul 2017

Cited by 3 | Viewed by 6441

Abstract

The challenging and innovative idea of realizing a table totally made of fiber-reinforced concrete is explored through an interdisciplinary research activity, where contributions coming from different fields (design, material science, experimental testing, numerical modeling) are combined. The paper describes the different phases of [...] Read more.

The challenging and innovative idea of realizing a table totally made of fiber-reinforced concrete is explored through an interdisciplinary research activity, where contributions coming from different fields (design, material science, experimental testing, numerical modeling) are combined. The paper describes the different phases of the study, starting from the design of the table, moving through the development of a purpose-made high-performance fiber-reinforced concrete and the mechanical characterization via experimental testing, and concluding with numerical modeling. Numerical results are determined by implementing a damage plasticity constitutive model in a finite element code. The mechanical response of the table has been analyzed for different loading and boundary conditions, and an exhaustive and complete picture of the possible failure mechanisms has been drawn. Simulations have clearly described the different stress-softening processes of damage evolution and plastic strains localization, pointing out the vulnerable parts of the table. Finally, strategies for improving the table mechanical performances are discussed. Full article

(This article belongs to the Special Issue Construction Materials Technologies)

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10 pages, 2892 KB

Open AccessArticle

Finite Element Analysis of Self-Healing and Damage Processes in Alumina/SiC Composite Ceramics

by Marika Nakamura, Kyohei Takeo, Toshio Osada and Shingo Ozaki

Technologies 2017, 5(3), 40; https://doi.org/10.3390/technologies5030040 - 23 Jun 2017

Cited by 12 | Viewed by 6896

Abstract

Among various ceramic matrix composites developed, self-healing ceramics have been studied as new functional materials. Self-healing occurs in such materials by high-temperature oxidation triggered by a micro-crack initiation on the surface, and the strength of the material autonomously recovers to its robust state [...] Read more.

Among various ceramic matrix composites developed, self-healing ceramics have been studied as new functional materials. Self-healing occurs in such materials by high-temperature oxidation triggered by a micro-crack initiation on the surface, and the strength of the material autonomously recovers to its robust state since the micro-crack is re-bonded. To facilitate the use of self-healing ceramics in machines and equipment, a novel numerical simulation method based on finite element analysis (FEA) needs to be applied. In this study, we applied a previously proposed constitutive model to a series of self-healing and damage processes. In the constitutive model, the damage process is formulated on the basis of fracture mechanics, while the self-healing process is formulated on the basis of empirical oxidation kinetics. The FEA model implemented the constitutive model to simulate a series of experiments of the alumina/15 vol% SiC composites. The self-healing process was targeted to a prescribed damage by Vickers indentation. Thereafter, the self-healing behavior was quantitatively compared with that observed in the experiment. The results suggest that the proposed FEA approach can be applied to the analysis of ceramic matrix composites with self-healing properties. Full article

(This article belongs to the Special Issue Ceramic Technologies and Applications)

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16 pages, 2524 KB

Open AccessArticle

Development of a Wearable Sensor Algorithm to Detect the Quantity and Kinematic Characteristics of Infant Arm Movement Bouts Produced across a Full Day in the Natural Environment

by Ivan A. Trujillo-Priego, Christianne J. Lane, Douglas L. Vanderbilt, Weiyang Deng, Gerald E. Loeb, Joanne Shida and Beth A. Smith

Technologies 2017, 5(3), 39; https://doi.org/10.3390/technologies5030039 - 23 Jun 2017

Cited by 42 | Viewed by 7353

Abstract

We developed a wearable sensor algorithm to determine the number of arm movement bouts an infant produces across a full day in the natural environment. Full-day infant arm movement was recorded from 33 infants (22 infants with typical development and 11 infants at [...] Read more.

We developed a wearable sensor algorithm to determine the number of arm movement bouts an infant produces across a full day in the natural environment. Full-day infant arm movement was recorded from 33 infants (22 infants with typical development and 11 infants at risk of atypical development) across multiple days and months by placing wearable sensors on each wrist. Twenty second sections of synchronized video data were used to compare the algorithm against visual observation as the gold standard for counting the number of arm movement bouts. Overall, the algorithm counted 173 bouts and the observer identified 180, resulting in a sensitivity of 90%. For each bout produced across the day, we then calculated the following kinematic characteristics: duration, average and peak acceleration, average and peak angular velocity, and type of movement (one arm only, both arms for some portion of the bout, or both arms for the entire bout). As the first step toward developing norms, we present average values of full-day arm movement kinematic characteristics across the first months of infancy for infants with typical development. Identifying and quantifying infant arm movement characteristics produced across a full day has potential application in early identification of developmental delays and the provision of early intervention therapies to support optimal infant development. Full article

(This article belongs to the Special Issue Personal Health and Wellbeing Intelligent Systems Based on Wearable and Mobile Technologies)

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14 pages, 739 KB

Open AccessCommunication

Beyond AI: Multi-Intelligence (MI) Combining Natural and Artificial Intelligences in Hybrid Beings and Systems

by Stephen Fox

Technologies 2017, 5(3), 38; https://doi.org/10.3390/technologies5030038 - 22 Jun 2017

Cited by 8 | Viewed by 10386

Abstract

Framing strongly influences actions among technology proponents and end-users. Underlying much debate about artificial intelligence (AI) are several fundamental shortcomings in its framing. First, discussion of AI is atheoretical, and therefore has limited potential for addressing the complexity of causation. Second, intelligence is [...] Read more.

Framing strongly influences actions among technology proponents and end-users. Underlying much debate about artificial intelligence (AI) are several fundamental shortcomings in its framing. First, discussion of AI is atheoretical, and therefore has limited potential for addressing the complexity of causation. Second, intelligence is considered from an anthropocentric perspective that sees human intelligence, and intelligence developed by humans, as superior to all other intelligences. Thus, the extensive post-anthropocentric research into intelligence is not given sufficient consideration. Third, AI is discussed often in reductionist mechanistic terms. Rather than in organicist emergentist terms as a contributor to multi-intelligence (MI) hybrid beings and/or systems. Thus, current framing of AI can be a self-validating reduction within which AI development is focused upon AI becoming the single-variable mechanism causing future effects. In this paper, AI is reframed as a contributor to MI. Full article

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Technologies, Volume 5, Issue 3 (September 2017) – 23 articles

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