Hide-n-Sense: Preserving Privacy Efficiently in Wireless mHealth

As healthcare in many countries faces an aging population and rising costs, mobile sensing technologies promise a new opportunity. Using mobile health (mHealth) sensing, which uses medical sensors to collect data about the patients, and mobile phones to act as a gateway between sensors and electronic health record systems, caregivers can continuously monitor the patients and deliver better care. Furthermore, individuals can become better engaged in monitoring and managing their own health. Although some work on mHealth sensing has addressed security, achieving strong privacy for low-power sensors remains a challenge. We make three contributions. First, we propose an mHealth sensing protocol that provides strong security and privacy properties at the link layer, with low energy overhead, suitable for low-power sensors. The protocol uses three novel techniques: adaptive security, to dynamically modify transmission overhead; MAC striping, to make forgery difficult even for small-sized Message Authentication Codes; and asymmetric resource requirements, in recognition of the limited resources in tiny mHealth sensors. Second, we demonstrate its feasibility by implementing a prototype on a Chronos wrist device, and evaluating it experimentally. Third, we provide a security, privacy, and energy analysis of our system.     

Aptamer‐Functionalized Multidimensional Conducting‐Polymer Nanoparticles for an Ultrasensitive and Selective Field‐Effect‐Transistor Endocrine‐Disruptor Sensors

An endocrine disruptor (ED) is a type of xenobiotic compound that can cause serious diseases related to the estrous cycle, as well as various types of cancer. At low ED concentrations, estrogen receptors may respond as they would under physiological conditions. In this work, aptamer‐functionalized multidimensional conducting‐polymer (3‐carboxylate polypyrrole) nanoparticles (A_M_CPPyNPs) are fabricated for use in an FET sensor to detect bisphenol A (BPA). The multidimensional system, M_CPPyNPs, is first produced by means of dual‐nozzle electrospray of pristine CPPyNPs and vapor deposition polymerization of additional conducting polymer. The M_CPPyNPs are then immobilized on an amine‐functionalized (–NH₂) interdigitated‐array electrode substrate, through the formation of covalent bonds with amide groups (–CONH). The amine‐functionalized BPA‐binding aptamer is then introduced in the same way as that for M_CPPyNP immobilization. The resulting A_M_CPPyNP‐based FET sensors exhibit ultrasensitivity and selectivity towards BPA at unprecedentedly low concentrations (1 fm ) and among molecules with similar structures. Additionally, due to the covalent bonding involved in the immobilization processes, a longer lifetime is expected for the FET sensor.     

Improving the photovoltaic performance of co‐evaporated Cu2ZnSnS4 thin‐film solar cells by incorporation of sodium from NaF layers

We have investigated the influence of sodium (Na) on the properties of co‐evaporated Cu₂ZnSnS₄ (CZTS) layer microstructures and solar cells. The photovoltaic performance and diode properties were improved by incorporating Na from NaF layers into the CZTS layers, while Na had a negligible effect on the microstructural properties of the layer. The best cell fabricated by using an optimal CZTS layer (Cu/(Zn + Sn) = 0.70, Zn/Sn = 1.8) yielded an active area efficiency of 5.23%. The analysis of device properties suggests that charge‐carrier recombination at CZTS/CdS interface is suppressed by intentional Na incorporation from NaF layers. Copyright © 2016 John Wiley & Sons, Ltd.     

Characterization of polymer-adhesive interfaces on a nanometre scale by elemental mapping and image EELS using EFTEM

Energy-filtering transmission electron microscopy (EFTEM) was applied for investigating interfaces between a polymer and an adhesive. The sample employed in this work is polybutylene terephtharate (PBT) sheets laminated with an epoxy adhesive. It was found that heat aging of the PBT at 180 degrees C in air for > 9 h prior to adhesion decreases the adhesion strength drastically. To investigate this unfavourable aging effect on the adhesion strength, we performed elemental mapping and image EELS using EFTEM. A weak boundary layer with a thickness of < 50 nm was visualized at the PBT-adhesive interface by elemental mapping in the sample subjected to the heat aging and image EELS revealed the origin of this layer. Thus, we clearly correlated the nanoscale interfacial structure with the adhesion strength by EFTEM.     

Group-Scheduling for Multi-Service Optical Burst Switching (OBS) Networks

We propose a new burst scheduling mechanism for Optical Burst-Switched (OBS) networks. The new approach is made possible by gathering data bursts into groups and performing the scheduling decision for each group collectively. In OBS group-scheduling, bursts will not be considered for scheduling until a pre-defined time period elapses, during which the group of burst header packets would be gathered. By transforming a set of data bursts into a set of corresponding time intervals, the problem of scheduling these bursts is transformed into a combinatorial optimization problem. Graph algorithms are applied to obtain the maximum number of non-overlapping bursts. The proposed OBS group-scheduling scheme is shown to improve the performance of OBS networks over existing scheduling schemes in terms of burst loss probability and channel utilization. With an extension through a sequential optimization, using a Branch-and-Bound technique, the proposed scheme can support multiple classes of service. It is shown that the new scheduling approach has several desired characteristics including fairness and service differentiability among classes in terms of burst loss probability and channel utilization.     

Development of intracranial brain-computer interface system using non-motor brain area for series of motor functions

An intracranial brain-computer interface (BCI) system using the neuronal activity of a non-motor brain area to fulfil a series of motor functions has been developed. The presented BCI system encodes a series of motor functions into a small number of neuronal units of the primary somatosensory cortex of a rat and generates real-time command signals to control a machine according to the animal's motor intentions. The results of this study demonstrate the practical usability of the BCI system using a non-motor brain area in the field of rehabilitation.     

Stator-flux-oriented control of induction motor considering ironloss

Research to consider the influences of iron loss has been made in the vector control of an induction motor. However, little work has been done in the area of a stator-flux-oriented control system of an induction motor. This paper investigates the effects of iron loss in the direct stator-flux-oriented control system of an induction motor, and proposes a control algorithm considering iron loss. The iron loss is modeled by equivalent iron loss resistance in parallel to the magnetizing inductance. Torque control capability is much improved and the speed estimation error for a speed-sensorless drive is reduced by the proposed control algorithm. The effectiveness of the proposed method is verified by simulation and experimental results     

Latch Applicator for Efficient Delivery of Dissolving Microneedles Based on Rapid Release of Elastic Strain Energy by Thumb Force (Adv. Funct. Mater. 11/2023)

Dissolving microneedle (DMN) is an attractive alternative to parenteral and enteral drug administration owing to its painless self-administration and safety due to non-generation of medical waste. For reproducible and efficient DMN administration, various DMN application methods, such as weights, springs, and electromagnetic devices, have been studied. However, these applicators have complex structures that are complicated to use and high production costs. In this study, a latch applicator that consists of only simple plastic parts and operates via thumb force without any external complex device is developed. Protrusion-shaped latches and impact distances are designed to accumulate thumb force energy through elastic deformation and to control impact velocity. The optimized latch applicator with a pressing force of 25 N and an impact velocity of 5.9 m s⁻¹ fully inserts the drug-loaded tip of the two-layered DMN into the skin. In an ovalbumin immunization test, DMN with the latch applicator shows a significantly higher IgG antibody production rate than that of intramuscular injection. The latch applicator, which provides effective DMN insertion and a competitive price compared with conventional syringes, has great potential to improve delivery of drugs, including vaccines.     

Ag Nanowire Reinforced Highly Stretchable Conductive Fibers for Wearable Electronics

Stretchable conductive fibers have received significant attention due to their possibility of being utilized in wearable and foldable electronics. Here, highly stretchable conductive fiber composed of silver nanowires (AgNWs) and silver nanoparticles (AgNPs) embedded in a styrene–butadiene–styrene (SBS) elastomeric matrix is fabricated. An AgNW‐embedded SBS fiber is fabricated by a simple wet spinning method. Then, the AgNPs are formed on both the surface and inner region of the AgNW‐embedded fiber via repeated cycles of silver precursor absorption and reduction processes. The AgNW‐embedded conductive fiber exhibits superior initial electrical conductivity (σ₀ = 2450 S cm^?1) and elongation at break (900% strain) due to the high weight percentage of the conductive fillers and the use of a highly stretchable SBS elastomer matrix. During the stretching, the embedded AgNWs act as conducting bridges between AgNPs, resulting in the preservation of electrical conductivity under high strain (the rate of conductivity degradation, σ/σ₀ = 4.4% at 100% strain). The AgNW‐embedded conductive fibers show the strain‐sensing behavior with a broad range of applied tensile strain. The AgNW reinforced highly stretchable conductive fibers can be embedded into a smart glove for detecting sign language by integrating five composite fibers in the glove, which can successfully perceive human motions.     

Empirical analysis of strategy selection for the technology leading and technology catch-up in the IT industry

R&D strategies of companies with low and high technological levels are discussed based on the concept of technology convergence and divergence. However, empirically detecting enterprise technology convergence in the distribution of enterprise technology (total productivity increase) over time and identifying key change factors are challenging. This study used a novel statistical indicator that captures the internal technology distribution change with a single number to clearly measure the technology distribution peak as a change in critical bandwidth for enterprise technology convergence and presented it as evidence of each technology convergence or divergence. Furthermore, this study applied the quantitative technology convergence identification method. Technology convergence appeared from the separation of total corporate productivity distribution of 69 IT companies in Korea in 2019–2020 rather than in 2015–2016. Results indicated that when the total technological level was separated from the technology leading and technology catch-up, IT companies were found to be pursuing R&D strategies for technology catch-up.