EEG miniaturization limits for stimulus decoding with EEG sensor networks

EEG intrahemispheric coherences (HCohs) in the resting state in twenty-four 4 Hz frequency windows between 1 and 51 Hz were studied in 18 children with "non-verbal learning disorder" (NLD) and compared to a group of 18 children with "verbal learning disorder" (VLD). New facts were found in the NLD group. These concern hemispheric balance, expressed as left minus right (L-R) homologous HCohs: 1a). In the high frequencies (25-51 HZ) the number of long-distance HCohs, higher in the right hemisphere (RH), is lower than HCohs, which are higher in the left hemisphere (LH). A reversed interhemispheric asymmetry is seen for short distance HCohs in that band. These asymmetries are not found in the VLD group, and the tendency is even reversed. 1b). In the low frequencies (1-27 Hz) all higher HCohs are more numerous in the RH, irrespective of interelectrode distance (IED). In these bands there are no NLD-VLD group differences; 2). In NLD there is a significant inverse relationship between IED and (L-R)HCoh values (designated as LRDif) in the high frequencies: the larger the IED, the higher the LRDif. In the lower frequencies there is no such tendency. In the VLD group these relationships were absent. These preliminary results suggest long distance gamma band hypoconnectivity in the RH of NLD children, in line with the hypothesis of an RH long distance connectivity problem in NLD. This may explain difficulties with mtermodal perception (gestalt function). Finally in the NLD group some gamma band interhemispheric (ICohs) over F7/F8 and T3/T4 were lower than in VLD children and some gamma band ICohs were higher in NLD compared to VLD over O1/O2. This is possibly connected with the cognitive differences subserved by these areas, i.e., language, respectively visuospatial function.

The effort in reducing the area of AES implementations has largely been focused on Application-Specific Integrated Circuits (ASICs) in which a tower field construction leads to a small design of the AES S-box. In contrast, a naive implementation of the AES S-box has been the status-quo on Field-Programmable Gate Arrays (FPGAs). A similar discrepancy holds for masking schemes – a wellknown side-channel analysis countermeasure – which are commonly optimized to achieve minimal area in ASICs.In this paper we demonstrate a representation of the AES S-box exploiting rotational symmetry which leads to a 50% reduction of the area footprint on FPGA devices. We present new AES implementations which improve on the state of the art and explore various trade-offs between area and latency. For instance, at the cost of increasing 4.5 times the latency, one of our design variants requires 25% less look-up tables (LUTs) than the smallest known AES on Xilinx FPGAs by Sasdrich and Guneysu at ASAP 2016. We further explore the protection of such implementations against first-order side-channel analysis attacks. Targeting the small area footprint on FPGAs, we introduce a heuristic-based algorithm to find a masking of a given function with d + 1 shares. Its application to our new construction of the AES S-box allows us to introduce the smallest masked AES implementation on Xilinx FPGAs, to-date.

While most lasers are linearly polarized, circularly polarized laser sources are crucial components for many optical applications such as biosensing, quantum technologies, and AR/VR. However, conventional methods for generating chiral light have limitations in device miniaturization. Vertical-cavity surface-emitting lasers (VCSELs), with their small footprint and surface emission feature, can be integrated with ultrathin metasurfaces for light manipulation, offering an opportunity to realize ultracompact chiral lasers. Here we report, to our knowledge, the first demonstration of chiral lasing from electrically pumped VCSELs at room temperature, without spin injection. This is enabled by incorporating a high-contrast chiral metasurface reflector as the VCSEL top mirror, favoring one specific circular polarization for lasing. Our demonstrated 940 nm VCSELs show stable single-mode chiral lasing and achieve a circular-polarization degree of up to 59%. This study provides a scalable approach for circular-polarization control of VCSELs and holds great promise for applications that desire ultracompact chiral emitters.

Thermal management has become a critical part of advanced micro and nano electronics systems due to high heat transfer rates. More constraints such as compactness, small footprint area, lightweight, high reliability, easy-access and low cost are exposed to thermal engineers. Advanced electronic systems such as laptops, tablets, smart phones and slim TV systems carry those challenging thermal needs. For these devices, smaller thermal real estates with higher heat fluxes than ever have created issues that current thermal technologies cannot meet those needs easily. Therefore, innovative cooling techniques are necessary to fulfill these aggressive thermal demands. Synthetic jets have been studied as a promising technology to satisfy the thermal needs of such tight electronics devices. The effect of nozzle-to-surface distance for a synthetic jet on its cooling performance has neither been studied extensively nor been well-understood. In a few available experimental studies, it was reported that synthetic jet performance is very sensitive to this distance and when the jet gets closer to the hot surface its performance degrades. Therefore, a computational study has been performed to understand the flow physics of a small-scale synthetic jet for a jet-to-surface spacing of H/D <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">h</sub> =5. Spatial discretization is implemented via a second order upwind scheme and a second order implicit scheme is used for temporal discretization to ensure stability. It is found that pulsating flow at the nozzle exit generates vortices and these vortices seem to have minimal effect on the target surface profiles. Local surface pressure, velocity, turbulence profiles and heat transfer coefficient distributions are determined, then the effects of jet frequency as well as near-wall vortices are discussed.

In this talk, I will present our results on the optomechanics of silicon photonic crystal based suspended membrane and edge-defect structures. We have studied and modeled the dynamic response of these devices, which has enabled us to design novel acoustic and magnetic sensors with very small footprint area. Using different edge defect 2D PC slab configurations we have studied the opto-mechanical coupling interaction both experimentally and via modelling. In these studies, we have observed interesting optical bistability and frequency combing phenomena.

As the technological demands for multiple‐input multiple‐output communication systems increasingly grow, there is a critical need for the next generation of multi‐beam radiators. The concept of single‐feed compact phase‐encoded metasurface antennas is introduced, the radiation specifications of which can be flexibly manipulated to provide circularly‐polarized single‐, dual‐, quad‐beam far‐field patterns, a circularly‐polarized optical angular momentum‐carrying beam, and a circularly‐polarized quasi‐omnidirectional emission. With a small footprint area at f = 5.8 GHz, the proposed circularly polarized coding metasurface antenna (CPCMA) consists of several radiating meta‐atoms with 2‐bit excitation phases of 0, π/2, π, and 3π/2. Compared with conventional antenna arrays, the center‐to‐center distance of the coding elements is noticeably reduced, where periodic boundary conditions have been employed to analyze the inter‐element coupling effects. A low‐cost and simple corporate feed network is also designed to implement the required coding mask of each CPCMA type. To verify the performance of the proposed CPCMA, a prototype is fabricated and measured. Proof‐of‐concept experiments demonstrate excellent agreement with numerical simulations and theoretical predictions. This constructs a bridge between conventional arrays and digital metasurfaces, providing a powerful host for the next generation of multi‐beam circularly polarized radiators.

This paper discusses the importance of developing cooling solutions for low profile devices. This is addressed with an experimental and theoretical study on forced convection cooling solution designs that could be implemented into such devices. Conventional finned and corresponding finless designs of equal exterior dimensions are considered for three different heat sink profiles ranging from 1 mm to 4 mm in combination with a commercially available radial blower. The results show that forced convection heat transfer rates can be enhanced by up to 55% using finless designs at low profiles with relatively small footprint areas. Overall, this paper provides optimization and geometry selection criteria, which are relevant to designers of low profile cooling solutions.

Efficient deployment of cameras optimizes the costs and benefits in a multicamera surveillance network. Most camera placement algorithms are developed for surveillance regions with predefined camera locations, where optimal orientation for every given camera location is determined to maximize coverage. The existing approaches to optimizing the number of cameras, locations, and orientations focus on specific scenarios and are neither generic nor scalable across diverse surveillance scenarios. This article proposes a generic and scalable reward penalty score (RPS) algorithm for optimal camera placement in diverse indoor and outdoor scenarios to efficiently attain a specified coverage requirement. The camera placement decision is driven by maximizing total coverage over the surveillance region with a minimum number of cameras at optimal locations and orientations. Based on the RPS algorithm, we extend the existing Greedy grid voting (GGV) algorithm that was limited to optimizing camera orientations for predefined locations. The extended GGV (EGGV) algorithm is broader in scope and optimizes the number of cameras, their locations, and orientations. Overall, the RPS algorithm produces superior coverage results over indoor and outdoor scenarios compared to the existing camera placement algorithms on map images of diverse surveillance scenarios ranging from small to large.

Magnetic components have become one of the primary barriers to high power density converters, especially to current-source converters (CSCs). In CSCs, the inductors/transformers have a predominantly dc flux to store energy, which can be offset by standard permanent magnets (PMs). However, eddy currents in standard PMs induce significant losses and thermal stress for medium-frequency applications. This article proposes using laminated PMs to offset the dc flux while reducing eddy currents, leading to significant reductions in the size, cost, and losses of inductors/transformers. Furthermore, the laminated PMs’ optimal location, orientation, and distribution are investigated to generalize this approach for maximum benefits. Three-dimensional finite-element analysis simulation and hardware experiments are presented to validate the effectiveness of the proposed approach in a medium-frequency transformer (MFT) for CSCs. Compared with standard PMs, the proposed use of laminated PMs reduces aggregate core-plus-PM losses by 85% in experiments, and thus, relaxes the MFT thermal design. Finally, the proposed approach is experimentally validated in a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{40}\,\text{kVA}$</tex-math></inline-formula> flyback-type MFT for a soft-switching solid-state transformer. Compared to the traditional design without any PMs, the proposed design increases the saturation current by 46% while inducing only 5% more losses, leading to significant savings in magnetics cost and size.

Reliability engineering challenges the complexity of systems, performance and environments. Reliable hardware is more challenging to reproduce due to component size, residues trapped under bottom terminations, shorter distance between conductors, higher pinout devices in a smaller footprint, increased electrical field and environmental factors. There is no one universal test method for quantifying reliability risks. The amount and nature of the data generated depends on the product being produced, the consequences of failure and the end-use environment. Residues under component terminations can impact device functions over time. The problem is that the standoff heights within the Z-Axis of miniaturized components are approaching one mil. During reflow, flux residues can become entrapped under the bottom terminations. Mobile ions within the flux residues form leakage currents, especially when the device is operating within humid environments. Ionics in flux residue can exacerbate contamination levels under the part, which can lead to high resistance shorts across pads. Companies who require devices to meet long term reliability must clean electronic hardware. This two part webtorial will teach Design for Cleaning and Reliability. Topics Covered: Session #1: Design for Cleaning Interrelationships surrounding the Cleaning Process Reduction of Residues under Bottom Terminated Components Cleaning Process Factors Matching the Cleaning Process to the Application Material Compatibility Process Control Tracking and Monitoring Session #2: Design for Reliability Failure Modes Materials Characterization Process Validation System Health Condition Monitoring Continuous Improvement Instructor Bio: Dr. Mike Bixenman is the Chief Technology Officer and Co-Founder of Kyzen Corporation. Mike is an active research fellow who tackles industry problems by running collaborative research studies with industry experts. The co-authors of this research - Mark McMeen and Jason Tynes of STI Electronics designed the Sensor Test Board / Test Method and David Lober of Kyzen Corporation worked on the test method. Kyzen has joined the STI research team to conduct research on an improved test method to measure the resistance of residues from non-cleaned and cleaned test boards using low residue solder pastes under a series of bottom terminated components. On Demand Webinar

Polarizer miter bends for high-power microwave transmission: Ohmic loss and cooling

In this paper, we investigate the short-range repulsion given by the quark cluster model employing an inverse scattering problem. We find that the local potential which reproduces the same phase shifts as those given by the quark cluster model has a strong repulsion at short distances in the $\mathrm{NN}{ }^{1}{S}_{0}$ channel. There, however, appears an attractive pocket at very short distances due to a rather weak repulsive behavior at very high energy. This repulsion-attractive-pocket structure becomes more manifest in the channel which has an almost forbidden state, $\ensuremath{\Sigma}N(T=3/2){ }^{3}{S}_{1}.$ In order to see what kinds of effects are important to reproduce the short-range repulsion in the quark cluster model, we investigate the contribution coming from the one-gluon-exchange potential and the normalization separately. It is clarified that the gluon exchange constructs the short-range repulsion in the $\mathrm{NN}{ }^{1}{S}_{0}$ while the quark Pauli-blocking effect governs the feature of the repulsive behavior in the $\ensuremath{\Sigma}N(T=3/2){ }^{3}{S}_{1}$ channel.

The scanning Kelvin probe shows great potential for the study of localised corrosion phenomena on coated metals. However, it still is difficult to unravel the contributions of the different components of complex coating systems to the measured Volta potentials. Experiments on simple model systems are necessary to increase our knowledge. The classical Evans drop experiment was chosen as such a model system. Using the scanning Kelvin probe potential distributions in the drop were measured. It was found that within the droplet no separate anode and cathode can be distinguished in the potential profile. A cathodic region was found just outside the droplet, where a very thin electrolyte layer exists. Twin drop experiments however showed potential differences in electrolyte over short distances.

Device-free hand gesture is one of the most natural ways to interact with everyday objects. However, existing WiFi-based gesture recognition solutions are typically restricted to indoor environments due to limited outdoor coverage. Furthermore, to achieve high sampling rates, they may interfere with normal data transmissions. In this paper, we aim to develop a robust dynamic gesture interaction system that can be ubiquitously deployed using Long-term Evolution (LTE) mobile terminals. Through both empirical studies and in-depth analysis using the Fresnel zone model, we reveal the key factors that contribute to the repeatability and discernibility of gestures. We show that the optimal location and orientation to perform gestures indeed exist and can be identified without prior knowledge of the position of LTE base stations (BSs) relative to a terminal. Guided by the design principles derived from Fresnel zone characteristics around a 4G terminal, we design highly repeatable and discernible gestures with salient received signal profiles. A gesture interaction system has been developed and implemented to achieve robust recognition with this careful design. Extensive experiments have been conducted in both indoor and outdoor environments, for different relative placements of mobile terminal and BS, and with different users. The proposed system can automatically identify the direction of BSs with a median error of less than 15 degrees and achieve gesture recognition accuracy as high as 98% in all scenarios without the need to acquire any training data.

Microfluidic (bio)-sensors based on 2-D layered materials