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Aims The main advantage of 3D-printed, off-the-shelf acetabular implants is the potential to promote enhanced bony fixation due to their controllable porous structure. In this study we investigated the extent of osseointegration in retrieved 3D-printed acetabular implants. Methods We compared two groups, one made via 3D-printing (n = 7) and the other using conventional techniques (n = 7). We collected implant details, type of surgery and removal technique, patient demographics, and clinical history. Bone integration was assessed by macroscopic visual analysis, followed by sectioning to allow undecalcified histology on eight sections (~200 µm) for each implant. The outcome measures considered were area of bone attachment (%), extent of bone ingrowth (%), bone-implant contact (%), and depth of ingrowth (%), and these were quantified using a line-intercept method. Results The two groups were matched for patient sex, age (61 and 63 years), time to revision (30 and 41 months), implant size (54 mm and 52 mm), and porosity (72% and 60%) (p > 0.152). There was no difference in visual bony attachment (p = 0.209). Histological analysis showed greater bone ingrowth in 3D-printed implants (p < 0.001), with mean bone attachment of 63% (SD 28%) and 37% (SD 20%), respectively. This was observed for all the outcome measures. Conclusion This was the first study to investigate osseointegration in retrieved 3D-printed acetabular implants. Greater bone ingrowth was found in 3D-printed implants, suggesting that better osseointegration can be achieved. However, the influence of specific surgeon, implant, and patient factors needs to be considered. Cite this article: Bone Joint Res 2021;10(7):388–400.

A new framework allows intelligence on mainstream end devices without special hardware.

In this article, we are interested in through-wall gait-based identification of multiple people who are simultaneously walking in an area, using only the WiFi magnitude measurements of a small number of transceivers. This is a considerably challenging problem as the gait signatures of the walking people are mixed up in the WiFi measurements. In order to solve this problem, we propose a novel multidimensional framework, spanning time, frequency, and space domains, that can separate the signal reflected from each walking person and extract its corresponding gait content, in order to identify multiple people through walls. To the best of our knowledge, this is the first time that WiFi signals can identify multiple people in an area. We extensively validate our proposed system with 92 test experiments conducted in four different areas, where the WiFi transceivers are placed behind walls, and where two or three people (randomly selected from a pool of six test subjects) are walking in the area. Our system achieves an overall average accuracy of 82% in correctly identifying whether a person walking in the test experiment (referred to as a query) is the same as a candidate person, based on 6404 query-candidate test pairs. It is noteworthy that none of the test subjects/areas has been seen in the training phase.

In this work, 22 off-the-shelf propellers of 15–40 inches in diameter are reverse-engineered using a scanning system and reverse engineering software. Geometric information, including the diameter and pitch of the propeller and its airfoil sections, are extracted, and the chord length and twist angle of the extracted airfoil sections are investigated. All processes for reverse engineering are validated through comparison with design drawing information, product and performance data of the KPROP propeller designed by Korea Aerospace Research Institute. Based on the validated process, a database of 22 commercial propellers from four companies is constructed containing all the reverse-engineered information. The chord length, the maximum length and twist angle with respect to the diameter of the extracted airfoil section are analyzed in comparison with each other depending on the company and propeller size. In addition, the thrust and torque are simulated using computational fluid dynamic methodology, and the predictions are compared with reference data provided by the manufacturers.

Building and programming tiny battery-free energy harvesting embedded computer systems is hard for the average maker because of the lack of tools, hard to comprehend programming models, and frequent power failures. With the high ecologic cost of equipping the next trillion embedded devices with batteries, it is critical to equip the makers, hobbyists, and novice embedded systems programmers with easy-to-use tools supporting battery-free energy harvesting application development. This way, makers can create untethered embedded systems that are not plugged into the wall, the desktop, or even a battery, providing numerous new applications and allowing for a more sustainable vision of ubiquitous computing. In this paper, we present BFree, a system that makes it possible for makers, hobbyists, and novice embedded programmers to develop battery-free applications using Python programming language and widely available hobbyist maker platforms. BFree provides energy harvesting hardware and a power failure resilient version of Python, with durable libraries that enable common coding practice and off the shelf sensors. We develop demonstration applications, benchmark BFree against battery-powered approaches, and evaluate our system in a user study. This work enables makers to engage with a future of ubiquitous computing that is useful, long-term, and environmentally responsible.

Autism spectrum disorder (ASD) is associated with deficits in the processing of social information and difficulties in social interaction, and individuals with ASD exhibit atypical attention and gaze. Traditionally, gaze studies have relied upon precise and constrained means of monitoring attention using expensive equipment in laboratories. In this work we develop a low-cost off-the-shelf alternative for measuring attention that can be used in natural settings. The head and iris positions of 104 16-31 months children, an age range appropriate for ASD screening and diagnosis, 22 of them diagnosed with ASD, were recorded using the front facing camera in an iPad while they watched on the device screen a movie displaying dynamic stimuli, social stimuli on the left and non-social stimuli on the right. The head and iris position were then automatically analyzed via computer vision algorithms to detect the direction of attention. We validate the proposed framework and computational tool showing that children in the ASD group paid less attention to the movie, showed less attention to the social as compared to the non-social stimuli, and often fixated their attention to one side of the screen. These results are expected from the ASD literature, here obtained with significantly simpler and less expensive attention tracking methods. The proposed method provides a low-cost means of monitoring attention to properly designed stimuli, demonstrating that the integration of stimuli design and automatic response analysis results in the opportunity to use off-the-shelf cameras to assess behavioral biomarkers.

Modern cities are densely populated spaces and number of people living in cities is increasing rapidly by years. The air monitoring stations exist in most of the cities to monitor air pollution. However, their number is insufficient having in mind the high cost of stations, as well as annual calibration cost. The potential solution is to use low-cost off-the-shelf sensors to monitor related air quality parameters, but they are not reliable due to the low accuracy, calibration issues, and short life cycle. In this paper, the methodology is proposed for calibration off-the-shelf air quality sensors using statistical algorithms and offset values from the official public measurement stations. The possibilities are analysed to improve the reliability of low-cost sensors by processing the obtained raw data. Special attention is devoted to the detection and elimination of short intervals when the raw results have the extraordinary high value-peaks and to the corresponding interpolation of these data. New algorithm for “peaks” detection and elimination is proposed and evaluated. Common Air Quality Index (CAQI) is calculated and evaluated in comparison with public monitoring station. It is shown that low-cost sensors could be used with high reliability as a complementary network to public monitoring stations.

Emerging memristor technology is as of late drawing broad consideration due to its potential for several applications. But, the non-availability of solid-state memristive devices puts a practical limitation. So, this paper proposed the concept and design of a practical memristor emulator, which can be used to imitate the behaviour of the well-known ideal memristor model developed by the HP Lab. This circuit contains off-the-shelf components such as AD844, AD633, voltage variable resistor (VVR) and few passive components. This circuit provides voltage tunability, an additional advantage over current tunability, which requires a complex circuitry. All the fingerprints of nano-scale memristor behavior are validated by the derived mathematical relations and simulation verification. Further, the robustness of the circuit has been demonstrated for statistical (10% deviation in passive components) and environmental variations (10% deviation in supply voltages). Also, the proposed circuit has been tested for a wide temperature range. Eventually, the proposed circuit is compared with the previously published emulators to illustrate the advantages of the proposed design.

Naked-eye sensing of phytic acid, one of the most abundant antinutrients, was achieved in 100% water medium using a charge transfer complex, composed of pyranine and methyl viologen. Since both the ingredients are commercially available, the design of such sensory systems needs zero synthetic effort, which essentially makes it economically viable. Only the physical mixture of both of these compounds showed a color-changing response from brown to yellow in the presence of phytic acid with a turn-on fluorescence response (LOD: 0.56 nM). The electrostatic interaction leads to charge pairing between phytic acid and methyl viologen, which releases free pyranine in solution. Considering its high sensitivity, low-cost test strips were developed for the on-site detection of phytic acid, even in remote locations. Additionally, estimation of phytic acid was achieved in grain samples with a sufficiently high accuracy, as evident from a sufficiently low relative standard deviation (

International audience; Automatic pain recognition from facial expressions is a challenging problem that has attracted a significant attention from the research community. This article provides a comprehensive analysis on the topic by comparing some popular and Off-the-Shell CNN (Convolutional Neural Network) architectures, including MobileNet, GoogleNet, ResNeXt-50, ResNet18, and DenseNet-161. We use these networks in two distinct modes: stand alone mode or feature extractor mode. In stand alone mode, the models (i.e., the networks) are used for directly estimating the pain. In feature extractor mode, the “values” of the middle layers are extracted and used as inputs to classifiers, such as SVR (Support Vector Regression) and RFR (Random Forest Regression). We perform extensive experiments on the benchmarking and publicly available database called UNBC-McMaster Shoulder Pain. The obtained results are interesting as they give valuable insights into the usefulness of the hidden CNN layers for automatic pain estimation.

Rapid advancements in UAVs, computing power and photogrammetry techniques now permit low cost biological-monitoring applications using off-the-shelf hardware and software. The utility of four UAV models costing $1,200 - $11, 000 and two photogrammetry programmes were assessed in separate experiments to evaluate their ability to detect standardised plant targets and to generate useable orthomoasic images. The colour and contrast of standardised targets influenced detection by UAVs more than their size as height increased. A large green rosette (50.8 cm2) could be detected by all UAVs from 28–90 m, while a yellow target 13 times smaller could be detected at 36–100 m, with the more expensive UAVs being effective at the higher altitudes. Monitoring vegetation cover or flowering plants is possible at the minimum allowable height altitude of 20 m by all four UAVs. However, identification of species in their vegetative state would require the UAVs with the better camera optics. The two photogrammetry programmes produced suitable orthomosaic images under the pasture, maize and hill country scenarios tested.

Service co-production between professionals and customers is an increasingly popular alternative to traditional “off the shelf” models of service delivery. There is, however, little empirical research describing how services are co-produced with individual customers, nor the most suitable roles for IS/IT in this co-production. This study unpacks how services are co-produced by developing a substantive Theory of Service Co-Production activities (and mediating contextual factors) in the financial services sector. A two-phase theory-building approach is employed. First, a preliminary model is derived based on Activity Theory and extant research. Second, this preliminary model is refined and elaborated upon through an extensive empirical analysis of the co-production of financial services. The study further reveals four key contradictions driving service co-production. These contradictions highlight the incomplete alignment of motives and goals between service professionals and customers, as well as the trickle-down IS/IT impact of this misalignment. The study concludes by discussing the enabling and constraining influence of IS/IT in service co-production.

In valvular replacement surgery, especially in the construction of bioprosthetic valves with decellularized pericardial xenograft, glutaraldehyde (GA) is routinely utilized as the golden standard reagent to fix bovine or porcine pericardial tissues. However, the apparent defects of GA, including cytotoxicity and calcification, increase the probability of leaflet failure and motivate the exploration for alternatives. Thus, the aim of this study is to develop nonglutaraldehyde combined-cross-linking reagents composed of alginate-EDC/NHS (Alg) or oxidized alginate-EDC/NHS (Alg-CHO) as substitute for GA, which is confirmed to be less toxic and more biocompatible. Evaluations of the fixed acellular bovine pericardial tissues included mechanical performance, thermodynamics/enzymatic/in vivo stability tests, blood compatibility assay, cytocompatibility assay, in vitro anticalcification, and in vivo anticalcification assay by subcutaneous implantation in juvenile Wistar rats. The data revealed that the tissues fixed with the combined cross-linking reagents were superior to GA control and commercially available Sino product in terms of better in vitro hemocompatibility and cytocompatibility, lower calcification levels, better thermodynamics stability, and better regenerative capacity in subcutaneous implants, while the mechanical strength and in vivo stability were comparable. Considering all above performances, it indicated that both Alg and Alg-CHO are appropriate to replace GA as the cross-linkers for biological tissue, particularly as a nonglutaraldehyde fixation for off the shelf decellularized bovine pericardial tissue in the anticalcification cardiac valve applications. Nevertheless, studies on the long-term durability and calcification-resistance capacity in large animal model are further needed.

The chronic kidney disease (CKD) and end-stage renal disease are the leading causes of kidney (renal) failure which may be fatal. Thus, it is important to diagnose the kidney diseases at an earlier...

Decellularized biological scaffolds hold great promise in cardiovascular surgery. In order to ensure off-the-shelf availability, routine use of decellularized scaffolds requires tissue banking. In this study, the suitability of cryopreservation, vitrification and freeze-drying for the preservation of decellularized bovine pericardial (DBP) scaffolds was evaluated. Cryopreservation was conducted using 10% DMSO and slow-rate freezing. Vitrification was performed using vitrification solution (VS83) and rapid cooling. Freeze-drying was done using a programmable freeze-dryer and sucrose as lyoprotectant. The impact of the preservation methods on the DBP extracellular matrix structure, integrity and composition was assessed using histology, biomechanical testing, spectroscopic and thermal analysis, and biochemistry. In addition, the cytocompatibility of the preserved scaffolds was also assessed. All preservation methods were found to be suitable to preserve the extracellular matrix structure and its components, with no apparent signs of collagen deterioration or denaturation, or loss of elastin and glycosaminoglycans. Biomechanical testing, however, showed that the cryopreserved DBP displayed a loss of extensibility compared to vitrified or freeze-dried scaffolds, which both displayed similar biomechanical behavior compared to non-preserved control scaffolds. In conclusion, cryopreservation altered the biomechanical behavior of the DBP scaffolds, which might lead to graft dysfunction in vivo. In contrast to cryopreservation and vitrification, freeze-drying is performed with non-toxic protective agents and does not require storage at ultra-low temperatures, thus allowing for a cost-effective and easy storage and transport. Due to these advantages, freeze-drying is a preferable method for the preservation of decellularized pericardium. Statement of Significance: Clinical use of DBP scaffolds for surgical reconstructions or substitutions requires development of a preservation technology that does not alter scaffold properties during long-term storage. Conclusive investigation on adverse impacts of the preservation methods on DBP matrix integrity is still missing. This work is aiming to close this gap by studying three potential preservation technologies, cryopreservation, vitrification and freeze-drying, in order to achieve the off-the-shelf availability of DBP patches for clinical application. Furthermore, it provides novel insights for dry-preservation of decellularized xenogeneic scaffolds that can be used in the routine clinical cardiovascular practice, allowing the surgeon the opportunity to choose an ideal implant matching with the needs of each patient.

We investigate the frictional force which is acting on a pipeline pig. Two complementary experimental setups have been designed and used to study the sealing disc of a pig, which is responsible for the frictional force between the pig and the pipe wall. Six 12 ' ' off the shelf sealing discs from two different vendors have been used. The first setup is a static setup in which the sealing disc is subjected to a normal wall force and a tangential friction force. A unique feature of the setup is that the ratio between the friction force and the wall force can be readily adjusted. This allows to experimentally determine the force ratio which is directly related to the Coulomb friction coefficient, which is often a difficult parameter to predict. Furthermore, the static setup is used to systematically study the effect of oversize, thickness, and Young's modulus of the sealing disc on the frictional force. A direct comparison with Finite Element (FE) calculations is made. The second experimental facility consist of a dynamic setup in which a sealing disc is pulled through a vertical 1.7 m long pipe. The effect of possible lubrication on the frictional force is studied by applying water to the sliding contact and comparing the results with dry pull tests for different sliding velocities. The corresponding difference in the Coulomb friction coefficient was quantified using FE calculations which were successfully verified with the static setup. The sensitivity of possible wear of the sealing disc on the frictional force is discussed.

Significant barriers to the diagnosis of latent and acute SARS-CoV-2 infection continue to hamper population-based screening efforts required to contain the COVID-19 pandemic in the absence of effective antiviral therapeutics or vaccines. We report an aptamer-based SARS-CoV-2 salivary antigen assay employing only low-cost reagents ($3.20/test) and an off-the-shelf glucometer. The test was engineered around a glucometer as it is quantitative, easy to use, and the most prevalent piece of diagnostic equipment globally making the test highly scalable with an infrastructure that is already in place. Furthermore, many glucometers connect to smartphones providing an opportunity to integrate with contract tracing apps, medical providers, and electronic medical records. In clinical testing, the developed assay detected SARS-CoV-2 infection in patient saliva across a range of viral loads - as benchmarked by RT-qPCR - within one hour, with 100% sensitivity (positive percent agreement) and distinguished infected specimens from off-target antigens in uninfected controls with 100% specificity (negative percent agreement). We propose that this approach can provide an inexpensive, rapid, and accurate diagnostic for distributed screening of SARS-CoV-2 infection at scale.

Chronic/non-healing cutaneous wounds pose a debilitating burden on patients and healthcare system. Presently, treatment modalities are rapidly shifting pace from conventional methods to advanced wound care involving cell-based therapies. Mesenchymal stem cells (MSCs) have come across as a prospective option due to its pleiotropic functions viz. non-immunogenicity, multipotency, multi-lineage plasticity and secretion of growth factors, cytokines, microRNAs (miRNA), exosomes, and microvesicles as part of their secretome for assisting wound healing. We outline the therapeutic role played by MSCs and its secretome in suppressing tissue inflammation, causing immunomodulation, aiding angiogenesis and assisting in scar-free wound healing. We further assess the mechanism of action by which MSCs contribute in manifesting tissue repair. The review flows ahead in exploring factors that influence healing behavior including effect of multiple donor sites, donor age and health status, tissue microenvironment, and in vitro expansion capability. Moving ahead, we overview the advancements achieved in extending the lifespan of cells upon implantation, influence of genetic modifications aimed at altering MSC cargo, and evaluating bioengineered matrix-assisted delivery methods toward faster healing in preclinical and clinical models. We also contribute toward highlighting the challenges faced in commercializing cell-based therapies as standard of care treatment regimens. Finally, we strongly advocate and highlight its application as a futuristic technology for revolutionizing tissue regeneration.

RFID is widely used in many security sensitive areas. Researchers proposed many theoretical attacks and security implementation models on RFID devices. To test these theories and models is challenging and difficult task. In this paper, we use three common-off-the-shelf security testing platforms i.e. PN532, TI RF430CL330H and Chameleon Mini, to test the most widely used standards ISO14443A, ISO14443B and ISO18092. We present a detailed workflow of each platform. Furthermore, we highlight the advantages and disadvantages of each platform in regards fast implementation, delays and support for different types of RFIDs.

Imaging photo-plethysmography (IPPG) technique has been proven to detect heart rate (HR) with a camera. Currently it might be used in a rigid scenario, such as the static subject, the short measurement distance and good illumination. In this paper, we try to relax these constraints by extending the measurement distance and applying it to the non-static subject with IPPG technique using the off-the-shelf camera. To achieve it, the landmark detection method is used to locate the facial region of interest (ROI) for the subject during movements. On this ROI, R/G/B channel signals are extracted with the spatial average of pixels. Then we use a skin appearance model (CHROME) to remove the noise, and HR is estimated from the output of the CHROME through the power spectrum. Experimental results showed that our method works effectively in both static and non-static scenarios. In static scenario, the measurement distance can extend to 4 meters, while the accuracy can reach 86% compared with the results from a finger detection equipment. In non-static scenario, our method achieve better results than previous studies.

The author proposes a new approach for bridge crack detection by a 360&deg, camera on top of a drone. Traditionally, bridge inspection is performed manually and although the use of drones has been implemented before, researchers used standard high definition cameras underneath the drone. To make the approach comparable to the conventional approach, two bridges were selected in Germany and inspected for cracks and defects by applying both methods. The author follows an engineering design process and after developing a prototype of the drone with a 360&deg, camera above the body of the drone, the system is built, tested, and the bridges are inspected. First, the critical parts of the bridges are inspected with an off-the-shelf drone with a high definition camera underneath the drone. The results provide a benchmark for comparison. Next, the new approach to bridge inspection by using a 360&deg, camera on top of the drone is tested. The images of the critical parts of the bridge that were taken with the 360&deg, camera on top of the drone are analyzed and compared to the images of the conventional approach with the camera underneath the drone. The results show that a 360&deg, camera can be used for crack and defect detection with similar results to a standard high definition camera. Furthermore, the 360&deg, camera is more suitable for inspecting corners or the ceiling of, e.g., an arch bridge.

In this paper we measure the accuracy of password strength meters (PSMs) using password guessing resistance against off-the-shelf guessing attacks. We consider 13 PSMs, 5 different attack tools, and a random selection of 60,000 passwords extracted from three different datasets of real-world password leaks. Our results show that a significant percentage of passwords classified as strong were cracked, thus suggesting that current password strength estimation methods can be improved.

Recent work showed that using image processing techniques on thermal images taken by high-end equipment reveals passwords entered on touchscreens and keyboards. In this paper, we investigate the susceptibility of common touch inputs to thermal attacks when non-expert attackers visually inspect thermal images. Using an off-the-shelf thermal camera, we collected thermal images of a smartphone's touchscreen and a laptop's touchpad after 25 participants had entered passwords using touch gestures and touch taps. We show that visual inspection of thermal images by 18 participants reveals the majority of passwords. Touch gestures are more vulnerable to thermal attacks (60.65% successful attacks) than touch taps (23.61%), and attacks against touchscreens are more accurate than on touchpads (87.04% vs 56.02%). We discuss how the affordability of thermal attacks and the nature of touch interactions make the threat ubiquitous, and the implications this has on security.

Malfunctioning heart valves can cause severe health problems, which if left untreated can lead to death. One of the treatment options is to replace a diseased heart valve with a decellularized valve construct prepared from human or animal material. Decellularized tissue scaffolds closely resemble properties of native tissue, while lacking immunogenic factors of cellular components. After transplantation, circulating stem and progenitor cells of the patient adhere to the scaffold resulting in in vivo tissue regeneration of the valve. Decellularized heart valve scaffold implants need to be stored to be readily available whenever needed, which can be done by freeze-drying. The advantage of freeze-drying is that it does not require bulky and energy-consuming freezing equipment for storage and allows easy transport. This chapter outlines the entire process from decellularization to freeze-drying to obtain dry decellularized heart valves, which after a simple rehydration step, can be used as implants. The protocol is described for porcine heart valves, but procedures can easily be adapted for material obtained from other species.

In the last decades, many approaches were presented to localize and decode barcodes in images from off the shelf cameras. However, all proposed solutions usually only deal with one type of image artifacts, such as a poorly illuminated or noisy image, or an image that suffers from motion or out-of-focus blur. In this paper, we present a complete, fully automatic pipeline, which allows the localization and decoding of barcodes in real-world scenarios. Our method is capable of localization and decoding the correct barcode information even if the input image is noisy, poorly exposed, and blurred at the same time. We can also decode the correct information from barcode images whose resolution is actually too low, i.e., where the width of the smallest bar depicted is smaller than the width of a single pixel.

This paper experimentally demonstrates a VLC sys-tem using a large off-the-shelf LED panel with dimensions of 60 × 60 cm2 and achieves a data rate of 40 Mb/s based on multi-band carrier-less amplitude and phase (CAP) modulation. The proposed system demonstrates the potential of utilising the existing LED-based lighting infrastructure for simultaneous indoor illumination and data communication.

Here, we developed a straightforward methodology to generate TCRαβ negative (allogeneic) cells for CAR-T cell therapies. With an early and transient expression of an anti-CD3 CAR in the engineered donor T cells, we programmed these cells to self-eliminate the TCR+ cell population and obtained an ultrapure TCRαβ- population (99-99.9%) at the end of the CAR-T production. This novel and easy-to-implement procedure preserves the production yield and cell fitness and has the potential to streamline the manufacturing of "off-the-shelf" CAR T-cell therapies.

WiFi sensing has recently attracted a lot of attention in providing a method for device-free sensing with standard WiFi devices through the use of Channel State Information (CSI). However, access to CSI from user-level applications is not provided by most WiFi devices, specifically ubiquitous smartphone devices. In this demonstration, we present our custom developed application for collecting, labeling and processing CSI on-device, in realtime, for standard off-the-shelf Android smartphones. We additionally demonstrate the use of our application on select device-free sensing tasks.

We present docExtractor, a generic approach for extracting visual elements such as text lines or illustrations from historical documents without requiring any real data annotation. We demonstrate it provides high-quality performances as an off-the-shelf system across a wide variety of datasets and leads to results on par with state-of-the-art when fine-tuned. We argue that the performance obtained without fine-tuning on a specific dataset is critical for applications, in particular in digital humanities, and that the line-level page segmentation we address is the most relevant for a general purpose element extraction engine. We rely on a fast generator of rich synthetic documents and design a fully convolutional network, which we show to generalize better than a detection-based approach. Furthermore, we introduce a new public dataset dubbed IlluHisDoc dedicated to the fine evaluation of illustration segmentation in historical documents., Comment: Accepted at 2020 17th International Conference on Frontiers in Handwriting Recognition (ICFHR) (oral). Project webpage: http://imagine.enpc.fr/~monniert/docExtractor/

We demonstrate simultaneous WDM-signal generation using an optical time-lens and off-the-shelf components. 32 WDM-channels with 50-GHz spacing are generated from a single SFP+ transceiver source and received using another SFP+ after 50-km unamplified transmission.

Sentiment analysis has become a very important tool for analysis of social media data. There are several methods developed, covering distinct aspects of the problem and disparate strategies. However, no single technique fits well in all cases or for all data sources. Supervised approaches may be able to adapt to specific situations, but require manually labeled training, which is very cumbersome and expensive to acquire, mainly for a new application. In this context, we propose to combine several popular and effective state‐of‐the‐practice sentiment analysis methods by means of an unsupervised bootstrapped strategy. One of our main goals is to reduce the large variability (low stability) of the unsupervised methods across different domains. The experimental results demonstrate that our combined method (aka, 10SENT) improves the effectiveness of the classification task, considering thirteen different data sets. Also, it tackles the key problem of cross‐domain low stability and produces the best (or close to best) results in almost all considered contexts, without any additional costs (e.g., manual labeling). Finally, we also investigate a transfer learning approach for sentiment analysis to gather additional (unsupervised) information for the proposed approach, and we show the potential of this technique to improve our results.

An equivalent model of slotted waveguide antennas (SWAs) is proposed for predicting the installed performance of an SWA whose detailed structure is difficult to obtain. The equivalent model is built with phaseless far-field (FF) information available from the vendor. The number of design parameters is reduced by considering the radiation mechanism of SWAs, leading to a fast optimization procedure. Different from existing reconstructed models, the proposed model is able to reproduce the radiating as well as the scattering performance of the original SWA and is thus suitable for evaluating the radiation of and the radio-frequency (RF) interference to the SWA on platforms. Simulation results demonstrate the effectiveness and efficiency. The proposed model enables the analysis of installed performance of SWAs with limited information, which can be useful when one buys an antenna off the shelf. It also avoids direct modeling of the complex SWA structure, requiring fewer computational resources.

Popularity and diverse use of 3D city models has increased exponentially in the past few years, providing a more realistic impression and understanding of cities. Often, 3D city models are created by elevating the buildings from a detailed 2D topographic base map and subsequently used in studies such as solar panel allocation, infrastructure remodelling, antenna installations or even tourist guide applications. However, the large amount of resulting data slows down rendering and visualisation of the 3D models, and can also impact the performance of any analysis. Generalisation enables a reduction in the amount of data – however the addition of the third dimension makes this process more complex, and the loss of detail resulting from the process will inevitably have an impact on the result of any subsequent analysis.While a few 3D generalization algorithms do exist in a research context, these are not available commercially. However, GIS users can create the generalised 3D models by simplifying and aggregating the 2D dataset first and then extruding it to the third dimension. This approach offers a rapid generalization process to create a dataset to underpin the impact of using generalised data for analysis. Specifically, in this study, the line of sight from a tall building and the sun shadow that it creates are calculated and compared, in both original and generalised datasets. The results obtained after the generalisation process are significant: both the number of polygons and the number of nodes are minimized by around 83 % and the volume of 3D buildings is reduced by 14.87 %. As expected, the spatial analyses processing times are also reduced. The study demonstrates the impact of generalisation on analytical results – which is particularly relevant in situations where detailed data is not available and will help to guide the development of future 3D generalisation algorithms. It also highlights some issues with the overall maturity of 3D analysis tools, which could be one factor limiting uptake of 3D GIS.

Machine learning models to predict energy expenditure (EE) from accelerometer data have traditionally been trained on data from laboratory-based activity trials. However, accuracy is typically attenuated when implemented in free-living scenarios. Currently, no studies involving preschool children have evaluated the accuracy of EE prediction models trained on laboratory (LAB) under free-living conditions. Purpose To evaluate the accuracy of LAB EE prediction models in preschool children completing a free-living active play session. Performance was benchmarked against EE prediction models trained on free living (FL) data. Methods 25 children (mean age = 4.1±1.0 y) completed a 20-minute active play session while wearing a portable indirect calorimeter and ActiGraph GT3X+ accelerometers on their right hip and non-dominant wrist. EE was predicted using LAB models which included Random Forest (RF) and Support Vector Machine (SVM) models for the wrist, and RF and Artificial Neural Network (ANN) models for the hip. Two variations of the LAB models were evaluated; 1) an "off the shelf" model without additional training; 2) models retrained on free-living data, replicating the methodology used in the original calibration study (retrained LAB). Prediction errors were evaluated in a hold-out sample of 10 children. Results Root mean square error (RMSE) for the FL and retrained LAB models ranged from 0.63- 0.67 kcals/min. In the hold out sample, RMSE's for the hip LAB (0.62-0.71), retrained LAB (0.58-0.62) and FL models (0.61-0.65) were similar. For the wrist placement, FL SVM had a significantly higher RMSE (0.73 ± 0.29 kcals/min) than the retrained LAB SVM (0.63 ± 0.30 kcals/min) and LAB SVM (0.64 ± 0.18 kcals/min). The LAB (0.64 ± 0.28), retrained LAB (0.64 ± 0.25), and FL (0.62 ± 0.26) RF exhibited comparable accuracy. Conclusion Machine learning EE prediction models trained on LAB and FL data had similar accuracy under free-living conditions.

Fixed pericardial tissue is commonly used for commercially available xenograft valve implants, and has proven durability, but lacks the capability to remodel and grow. Decellularized porcine pericardial tissue has the promise to outperform fixed tissue and remodel, but the decellularization process has been shown to damage the collagen structure and reduce mechanical integrity of the tissue. Therefore, a comparison of uniaxial tensile properties was performed on decellularized, decellularized‐sterilized, fixed, and native porcine pericardial tissue versus native valve leaflet cusps. The results of non‐parametric analysis showed statistically significant differences (p .05). Scanning electron microscopy confirmed that valvular endothelial and interstitial cells colonized the decellularized pericardial surface when seeded and grown for 30 days in static culture. Collagen assays and transmission electron microscopy analysis showed limited reductions in collagen with processing; yet glycosaminoglycan assays showed great reductions in the processed pericardium relative to native cusps. Decellularized pericardium had comparatively low mechanical properties among the groups studied; yet the stiffness was comparatively similar to the native cusps and demonstrated a lack of cytotoxicity. Suture retention, accelerated wear, and hydrodynamic testing of prototype decellularized and decell‐sterilized valves showed positive functionality. Sterilized tissue could mimic valvular mechanical environment in vitro, therefore making it a viable potential candidate for off‐the‐shelf tissue‐engineered valvular applications.

While metal halide perovskite solar cells (PVSCs) have drawn intense attention due to their high solar-to-power conversion efficiency (PCE), their practical application is hampered by their poor long-term stability against moisture. Although strategies have been reported to solve this issue, these methods are introduced during core-device fabrication processes which will increase the risk of introducing unexpected impurities during the fabrication. Herein, we introduce the first kind of simple post-device ligand (PDL) treatment to significantly improve the PCE of completely fabricated PVSCs from 18.7% to 20.13%. Meanwhile, the stability of the treated devices without any encapsulation remarkably improves, with 70% PCE maintained under ambient conditions after a 500-hour maximum-power-point tracking test, while the control unencapsulated device will completely break down within 100 hours. Equally important is that this post-device treatment shows a special ‘stitching effect’, namely repairing the as-fabricated ‘poor devices’ by healing the defects of the perovskite active region, and can improve the PCE by over 900%. We also experimentally and theoretically study the fundamental mechanism of the improvement. Consequently, our approach greatly improves the production yield of high-quality PVSCs and their module performances as well as the reduction of lead-waste. Additionally, the treatment is an off-the-shelf post-device approach that can be integrated into any existing perovskite-device fabrication, offering a general strategy to improve the stability and performance of perovskite optoelectronic devices.

Viologens and the stable, water-soluble nitroxide radical known as TEMPOL have been studied extensively with respect to applications in energy storage. Here we report formulations wherein high concentrations of both are achieved in a single solution and the reversible electrochemistry of each is retained. We demonstrate one of several potential applications by constructing a high optical density electrochromic device.

What do you do when you need to design energy or weight saving part for an aerospace, marine, automotive or robotics system and the perfect material is not available? Desirable properties not normally found in an off the shelf material. Properties for example low density, high strength, high modulus and low coefficient of thermal expansion (CTE). One answer is to select several materials that have the desired properties and mix them together to produce an engineered material with the combination of desired properties. This is primarily how composites are designed, including metal matrix composites (MMCs). One lightweight MMC system specifically aluminum-SiC MMCs is described in this article which combine a low density moderate strength ductile aluminum matrix with a low CTE, high strength silicon carbide reinforcement.

Buying off the shelf procurements (OTS) has become an important part of the national acquisition strategy in several countries, and this paper seeks to bring empirical evidence on OTS as the preferred acquisition strategy by use of data from 2015 to 2022 investment portfolio of the Norwegian Armed Forces. We develop definitions for three categories of procurement – OTS, modified OTS and development projects – as well as a method to classify projects into these categories. Our first finding is that the characteristics of OTS projects correspond to modified OTS and development projects. Our second finding indicates that OTS projects perform better when it comes to the completion of projects according to the initial schedule, compared to development projects.

Cell-based regenerative medicine strategies hold a great potential to revolutionize the treatment of a large number of injuries with limited regenerative potential. However, the effectiveness of the simple injection of a cell suspension in a target site/tissue of action is often limited by the dispersion of cells toward other tissues, hindering their therapeutic action. Nevertheless, the development of a custom-made cell carrier that can perfectly fit a patientâ s defect and be ready on demand is still a challenging task. The present study proposes the development of an off-the-shelf injectable cell delivery system combining a photocross-linkable hyaluronic acid (HA) matrix enriched with platelet lysate (PL) and human adipose tissue- derived stem cells (hASCs), which can be stored using standard cryopreservation methods and used when required. The obtained results indicate that the mechanical and viscoelastic properties of the system are improved in the presence of cells and no significant differences were identified between cell- laden hydrogels produced before or after cryopreservation. In PL-enriched hydrogels, cells tend to better recover from cryopreservation maintaining the values of cell viability and DNA content. Moreover, viable cells laden in our system and expressing stemness markers were detected after 21 days in culture. Altogether, the results obtained in this work demon- strate the potential of the developed strategy as an injectable cell delivery system for ready-to-use applications or as a cryo- preserved product to be available on demand for cell-based therapies.Â, The authors wish to acknowledge the financial support from the Portuguese Foundation for Science and Technology (FCT) for the PhD grant of R.C-A (SFRH/BD/96593/2013), post-doctoral grant of M.T.R (SFRH/BPD/111729/2015), grant of M.E.G. (IF/00685/2012) and Recognize project (UTAP-ICDT/CTM-BIO/0023/2014), RL3-TECT - NORTE-07-0124-FEDER-000020 project co-financed by ON.2 (NSRF) through ERD. The authors also acknowledge the financial support from FCT/MCTES (Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia, e Ensino Superior) and the Fundo Social Europeu through Programa Operacional do Capital Humano (FSE/POCH) PD/59/2013 for the PhD grant of A.I.G (PD/BD/113802/2015), and LA ICVS-3Bs (UID/Multi/50026/2013). The authors would also thank to Serviço de Imuno-Hemoterapia, Centro Hospitalar São João, EPE (Porto, Portugal) for providing human platelet concentrate samples., info:eu-repo/semantics/publishedVersion

Biometric authentication is increasingly being used for large scale human authentication and identification, creating the risk of leaking the biometric secrets of millions of users in the case of database compromise. Powerful "fuzzy" cryptographic techniques for biometric template protection, such as secure sketches, could help in principle, but go unused in practice. This is because they would require new biometric matching algorithms with potentially much diminished accuracy. We introduce a new primitive called a multisketch that generalizes secure sketches. Multisketches can work with existing biometric matching algorithms to generate strong cryptographic keys from biometric data reliably. A multisketch works on a biometric database containing multiple biometrics --- e.g., multiple fingerprints --- of a moderately large population of users (say, thousands). It conceals the correspondence between users and their biometric templates, preventing an attacker from learning the biometric data of a user in the advent of a breach, but enabling derivation of user-specific secret keys upon successful user authentication. We design a multisketch over tenprints --- fingerprints of ten fingers --- called TenSketch. We report on a prototype implementation of TenSketch, showing its feasibility in practice. We explore several possible attacks against TenSketch database and show, via simulations with real tenprint datasets, that an attacker must perform a large amount of computation to learn any meaningful information from a stolen TenSketch database.

Photoplethysmography is a well-established minimally invasive method for estimating heart rate and blood oxygen saturation in clinical settings. Photoplethysmography, with limitations, can also be extended to estimate respiration rate. Recently many off the shelf photoplethysmography sensors have been released in a form factor suitable for wearable devices. In this study we evaluate two photoplethysmography front ends (inclusive of suitable signal conditioning module and digitizer) from Maxim Integrated™. The tri-wavelength MAX30101 sensor and bi-wavelength MAX30102 sensor were evaluated on the forehead, in a truly non-obtrusive wearable friendly position. Heart rate, respiration rate and blood oxygen saturation were extracted from both sensors and compared with a FDA/TGA/CE approved photoplethysmography device placed on the finger. All data were captured simultaneously and at rest. The MAX30101 sensor was more accurate in measuring heart rate, blood oxygen saturation and respiration rate compared to the MAX30102. Additionally, we found that the red wavelength was best for measuring heart rate and the green wavelength was best for respiration rate.

International audience; The use of Unmanned Aerial Vehicles (UAVs) is rising constantly whether for leisure or professional purposes in civilian or Defense domains. We consider in this study small civilian aerial drones of different types, which are low cost, available off the shelf and so affordable for individuals. Simultaneously , they have also raised security concerns for critical sites such as nuclear stations, strategic locations like official buildings, crowded places as stadiums, etc. The aim of this paper is to provide a survey of the risks assessment with and for UAVs in general. Regarding the security concern we pay a specific attention to attacks that are facilitated and can benefit from an easy access to Software Defined Radio (SDR) boards that can be embedded in the UAV or in the ground segment.

A three-unit colorimetric sensor array in aim of detecting heavy metal ions has been constructed with two off-the-shelf dyes. Multivariate data analysis is performed using LDA and HCA to recognize colour change patterns based on both absorption spectra and RGB values from image scans. The sensor array is able to differentiate 15 metal ions not only in separate solutions, but also mixtures of 3, 5, and 7 different metal ions and real water samples.

3D bioprinting has become a versatile and powerful method in tissue engineering and regenerative medicine and is increasingly adapted by other disciplines due to its tremendous potential beyond its typical applications. However, commercially available 3D bioprinting systems are typically expensive circumventing the broad implementation, including laboratories in low-resource settings. To address the limitations of conventional and commercially available technology, we developed a 3D bioprinter by modification of an off-the-shelf 3D desktop printer, that can be installed within a single day, is of handy size to fit into a standard laminar flow hood, customizable, ultra-low cost and thus, affordable to a broad range of research labs, or educational institutions. We evaluate accuracy and reproducibility of printing results using alginate and alginate/gelatin-hydrogels and demonstrate its potential for biomedical use by printing of various two-and three-dimensional cell-free and mammalian cell-laden objects using recombinant HEKYFP cells, stably expressing yellow fluorescent protein (YFP) as a model system and high-content imaging. We further provide a parts list and 3D design files in STL and STEP format for reconstructing the device. A time-lapse video of the custom-built device during operation is available at https://vimeo.com/274482794.

Photoisomerisation has been shown to be an efficient excited-state relaxation mechanism for a variety of nature-based and artificial-based molecular systems. Here we report on the excited-state relaxation dynamics and consequent photostability of a symmetrically functionalised cinnamate by transient electronic absorption spectroscopy, along with complementary computational and steady-state spectroscopy methods. The findings are then discussed in comparison to 2-ethylhexyl-E-4-methoxycinnamate, a structurally related ‘off the shelf’ chemical filter present in commercial sunscreens with a similar absorption profile. The present study allows for a like-for-like comparison beween 2-ethylhexyl-E-4-methoxycinnamate and the functionalised cinnamate, driven by the need to enhance solar protection across both the UVA and UVB regions of the electromagnetic spectrum.\ud \ud

The widespread deployment of the Internet of Things requires new embedded systems providing functionality with extremely low power consumption. This paper presents a battery-less, low-power consumption, compact embedded system using remote RF powering with COTS (Components Off The Shelf), and OOK or ASK based data communications, operating in the 900 MHz band.

We present a low temperature and low pressure approach to multijunction solar cell fabrication combining the high efficiency multi-junction concept with the low cost of thin film technology in one solar cell structure. The intermetallic bonding approach presented bonds indium metal covering metal contacts of the respective solar cells. This approach avoids lattice mismatch and tunnel junction limitations in connecting solar cells of any material and permits bonding of commercial off the shelf devices or textured surfaces. A two or three terminal GaAs/Si multijunction solar cell bonded using this approach is demonstrated using an off the shelf Si solar cell.

The Global Navigation Satellite System (GNSS) is by far the most used system for vehicle self-localization. However, it often fails in urban environments because of signal outages and other interference. To overcome this issue, roof-mounted LiDARs are often used by autonomous driving system developers. From a design point of view, such sensors are not appealing to the public users. Body-embedded sensors do not provide enough information because of placement and size constraints. In this paper, we show how to overcome all these constraints and achieve highly acceptable accuracy allowing reliable autonomous behavior. The proposed method's validity was demonstrated by an autonomous vehicle run in a typical urban environment.