Stimulation and measurement patterns versus prior information for fast 3D EIT: A breast screening case study

Imposing prior information is a typical strategy in inverse problems in return for a stable numerical algorithm. For a given imaging system configuration, Picard's stability condition could be deployed as a practical measure of the performance of the system against various priors and noise contaminated measurements. Herein, we make extensive use of this measure to quantify the performance of impedance imaging systems for various injection patterns. In effect, we numerically demonstrate that by varying electrode distributions and numbers, little improvement, if any, in the performance of the impedance imaging system is recorded. In contrast, by using groups of electrodes in the 3D current injection process, a step increase in performance is obtained. Numerical results on a female breast phantom reveal that the performance measure of the imaging system is 15% for a conventional combination of stimulation and prior information, 61% for groups of electrodes and the same prior and 97% for groups of electrodes and a more accurate prior. Finally, since a smaller number of electrodes is involved in the measurement process, a smaller number of measurements is acquired. However, no compromise in the quality of the reconstructed images is observed

A spectrally-accurate FVTD technique for complicated amplification and reconfigurable filtering EMC devices

The consistent and computationally economical analysis of demanding amplification and filtering structures is introduced in this paper via a new spectrally-precise finite-volume time-domain algorithm. Combining a family of spatial derivative approximators with controllable accuracy in general curvilinear coordinates, the proposed method employs a fully conservative field flux formulation to derive electromagnetic quantities in areas with fine structural details. Moreover, the resulting 3-D operators assign the appropriate weight to each spatial stencil at arbitrary media interfaces, while for periodic components the domain is systematically divided to a number of nonoverlapping subdomains. Numerical results from various real-world configurations verify our technique and reveal its universality

The usage and perception of pedestrian and cycling streets on residents’ well-being in Kalamaria, Greece

Pedestrian zones are public spaces intended for the continued and safe mobility of pedestrians and people with disabilities, and they provide multiple benefits to urban areas. They counterbalance the densely built-up areas, decrease atmospheric pollution, increase available green or social space, increase walking and cycling rates, and facilitate active play for children. Done properly, pedestrianization may also increase local business sales. Greece boasts open public spaces and the pedestrianization of common roads. The economic crisis that Greece has been experiencing since 2008 has led people to give up their vehicles and use the pedestrian streets more frequently. The purpose of this paper was to investigate residents’ perceptions and satisfaction rates concerning the pedestrian streets of Kalamaria, Greece, and evaluate their importance for residents’ well-being. Following a random sampling method, 400 residents were interviewed. A two-step cluster analysis was conducted. The survey showed that the urban residents visited pedestrian zones in Kalamaria at least once a week, and the visits lasted 46–60 min. The improvement of urban landscape aesthetics and people’s health and well-being were evaluated as important functions of pedestrian zones. The results also indicate that residents were not satisfied with their quality of life and the existing green infrastructures of the pedestrian streets, even though they have a positive disposition toward the construction or transformation of pedestrian streets. The residents expressed their unwillingness to pay more public taxes for the construction and maintenance of pedestrian and cycling streets. The safety and convenience of the mobility of residents were the most important advantages of the pedestrian streets. Meanwhile, overspill parking and difficulties with finding parking spaces were the main disadvantages for the residents. Local authorities can use the results of the present survey to manage the city’s green infrastructure and use this information in the urban planning framework.info:eu-repo/semantics/publishedVersio

Sound symbolism facilitates long-term retention of the semantic representation of novel verbs in three-year-olds

Previous research has shown that sound symbolism facilitates action label learning when the test trial used to assess learning immediately followed the training trial in which the (novel) verb was taught. The current study investigated whether sound symbolism benefits verb learning in the long term. Forty-nine children were taught either sound-symbolically matching or mismatching pairs made up of a novel verb and an action video. The following day, the children were asked whether a verb can be used for a scene shown in a video. They were tested with four videos for each word they had been taught. The four videos differed as to whether they contained the same or different actions and actors as in the training video: (1) same-action, same-actor; (2) same-action, different-actor; (3) different-action, same-actor; and (4) different-action, different-actor. The results showed that sound symbolism significantly improved the childrens’ ability to encode the semantic representation of the novel verb and correctly generalise it to a new event the following day. A control experiment ruled out the possibility that children were generalising to the “same-action, different-actor” video because they did not recognize the actor change due to the memory decay. Nineteen children were presented with the stimulus videos that had also been shown to children in the sound symbolic match condition in Experiment 1, but this time the videos were not labeled. In the test session the following day, the experimenter tested the children’s recognition memory for the videos. The results indicated that the children could detect the actor change from the original training video a day later. The results of the main experiment and the control experiment support the idea that a motivated (iconic) link between form and meaning facilitates the symbolic development in children. The current study, along with recent related studies, provided further evidence for an iconic advantage in symbol development in the domain of verb learning. A motivated form-meaning relationship can help children learn new words and store them long term in the mental lexicon

Joint Compressed Sensing and Manipulation of Wireless Emissions with Intelligent Surfaces

Programmable, intelligent surfaces can manipulate electromagnetic waves impinging upon them, producing arbitrarily shaped reflection, refraction and diffraction, to the benefit of wireless users. Moreover, in their recent form of HyperSurfaces, they have acquired inter-networking capabilities, enabling the Internet of Material Properties with immense potential in wireless communications. However, as with any system with inputs and outputs, accurate sensing of the impinging wave attributes is imperative for programming HyperSurfaces to obtain a required response. Related solutions include field nano-sensors embedded within HyperSurfaces to perform minute measurements over the area of the HyperSurface, as well as external sensing systems. The present work proposes a sensing system that can operate without such additional hardware. The novel scheme programs the HyperSurface to perform compressed sensing of the impinging wave via simple one-antenna power measurements. The HyperSurface can jointly be programmed for both wave sensing and wave manipulation duties at the same time. Evaluation via simulations validates the concept and highlight its promising potential.Comment: Published at IEEE DCOSS 2019 / IoT4.0 workshop (https://www.dcoss.org/workshops.html). Funded by the European Union via the Horizon 2020: Future Emerging Topics - Research and Innovation Action call (FETOPEN-RIA), grant EU736876, project VISORSURF (http://www.visorsurf.eu

Pseudo-Hermiticity and Electromagnetic Wave Propagation: The case of anisotropic and lossy media

Pseudo-Hermitian operators can be used in modeling electromagnetic wave propagation in stationary lossless media. We extend this method to a class of non-dispersive anisotropic media that may display loss or gain. We explore three concrete models to demonstrate the utility of our general results and reveal the physical meaning of pseudo-Hermiticity and quasi-Hermiticity of the relevant wave operator. In particular, we consider a uniaxial model where this operator is not diagonalizable. This implies left-handedness of the medium in the sense that only clockwise circularly polarized plane-wave solutions are bounded functions of time.Comment: 12 pages, Published Versio

Participatory citizenship: critical perspectives on client-centred occupational therapy

Background/aims: This article aims to discuss client-centred practice, the current dominant approach within occupational therapy, in relation to participatory citizenship. Occupational therapists work within structures and policies that set boundaries on their engagement with clients, while working with complex, multidimensional social realities. Methods: The authors present a critical discussion shaped by their research, including a survey, discussions at workshops at international conferences, and critical engagement with the literature on occupational therapy, occupation, and citizenship. Conclusion: A focus on citizenship suggests reframing professional development based on the participation in public life of people as citizens of their society. While occupational therapists often refer to clients in the context of communities, groups, families, and wider society, the term client centred practice typically represents a particular view of the individual and may sometimes be too limited in application for a more systemic and societal approach. Significance: The authors question the individual focus which has, until recently, been typical of client-centred occupational therapy. Placing citizenship at the core of intervention is a transformative process that assumes all people are citizens and conceives of health as a collective issue, influencing the way we educate, do research, and practise. Key words: Collective, dis-citizenship, inequalities, professional development, participation, paradigms, occupational justice</p

Automatic 3D Reconstruction of Coronary Artery Centerlines from Monoplane X-ray Angiogram Images

We present a new method for the fully automatic 3D reconstruction of the coronary artery centerlines, using two X-ray angiogram projection images from a single rotating monoplane acquisition system. During the first stage, the input images are smoothed using curve evolution techniques. Next, a simple yet efficient multiscale method, based on the information of the Hessian matrix, for the enhancement of the vascular structure is introduced. Hysteresis thresholding using different image quantiles, is used to threshold the arteries. This stage is followed by a thinning procedure to extract the centerlines. The resulting skeleton image is then pruned using morphological and pattern recognition techniques to remove non-vessel like structures. Finally, edge-based stereo correspondence is solved using a parallel evolutionary optimization method based on f symbiosis. The detected 2D centerlines combined with disparity map information allow the reconstruction of the 3D vessel centerlines. The proposed method has been evaluated on patient data sets for evaluation purposes

Intelligent Metasurfaces with Continuously Tunable Local Surface Impedance for Multiple Reconfigurable Functions

Electromagnetic metasurfaces can be characterized as intelligent if they are able to perform multiple tunable functions, with the desired response being controlled by a computer influencing the individual electromagnetic properties of each metasurface inclusion. In this paper, we present an example of an intelligent metasurface which operates in the reflection mode in the microwave frequency range. We numerically show that without changing the main body of the metasurface we can achieve tunable perfect absorption and tunable anomalous reflection. The tunability features can be implemented using mixed-signal integrated circuits (ICs), which can independently vary both the resistance and reactance, offering complete local control over the complex surface impedance. The ICs are embedded in the unit cells by connecting two metal patches over a thin grounded substrate and the reflection property of the intelligent metasurface can be readily controlled by a computer. Our intelligent metasurface can have significant influence on future space-time modulated metasurfaces and a multitude of applications, such as beam steering, energy harvesting, and communications.Comment: 10 pages, 8 figure

Connectivity and coverage in machine-type communications

Machine-type communication (MTC) provides a potential playground for deploying machine-to-machine (M2M), IP-enabled 'things' and wireless sensor networks (WSNs) that support modern, added-value services and applications. 4G/5G technology can facilitate the connectivity and the coverage of the MTC entities and elements by providing M2M-enabled gateways and base stations for carrying traffic streams to/from the backbone network. For example, the latest releases of long-term evolution (LTE) such as LTE-Advanced (LTE-A) are being transformed to support the migration of M2M devices. MTC-oriented technical definitions and requirements are defined to support the emerging M2M proliferation. ETSI describes three types of MTC access methods, namely a) the direct access, b) the gateway access and c) the coordinator access. This work is focused on studying coverage aspects when a gateway access takes place. A deployment planar field is considered where a number of M2M devices are randomly deployed, e.g., a hospital where body sensor networks form a M2M infrastructure. An analytical framework is devised that computes the average number of connected M2M devices when a M2C gateway is randomly placed for supporting connectivity access to the M2M devices. The introduced analytical framework is verified by simulation and numerical results