Spatial Changes in the Atrial Fibrillation Wave-Dynamics After Using Antiarrhythmic Drugs: A Computational Modeling Study

Background: We previously reported that a computational modeling-guided antiarrhythmic drug (AAD) test was feasible for evaluating multiple AADs in patients with atrial fibrillation (AF). We explored the anti-AF mechanisms of AADs and spatial change in the AF wave-dynamics by a realistic computational model.Methods: We used realistic computational modeling of 25 AF patients (68% male, 59.8 ± 9.8 years old, 32.0% paroxysmal AF) reflecting the anatomy, histology, and electrophysiology of the left atrium (LA) to characterize the effects of five AADs (amiodarone, sotalol, dronedarone, flecainide, and propafenone). We evaluated the spatial change in the AF wave-dynamics by measuring the mean dominant frequency (DF) and its coefficient of variation [dominant frequency-coefficient of variation (DF-COV)] in 10 segments of the LA. The mean DF and DF-COV were compared according to the pulmonary vein (PV) vs. extra-PV, maximal slope of the restitution curves (Smax), and defragmentation of AF.Results: The mean DF decreased after the administration of AADs in the dose dependent manner (p < 0.001). Under AADs, the DF was significantly lower (p < 0.001) and COV-DF higher (p = 0.003) in the PV than extra-PV region. The mean DF was significantly lower at a high Smax (≥1.4) than a lower Smax condition under AADs. During the episodes of AF defragmentation, the mean DF was lower (p < 0.001), but the COV-DF was higher (p < 0.001) than that in those without defragmentation.Conclusions: The DF reduction with AADs is predominant in the PVs and during a high Smax condition and causes AF termination or defragmentation during a lower DF and spatially unstable (higher DF-COV) condition

Hardware/Software Co-Design for TinyML Voice-Recognition Application on Resource Frugal Edge Devices

On-device artificial intelligence has attracted attention globally, and attempts to combine the internet of things and TinyML (machine learning) applications are increasing. Although most edge devices have limited resources, time and energy costs are important when running TinyML applications. In this paper, we propose a structure in which the part that preprocesses externally input data in the TinyML application is distributed to the hardware. These processes are performed using software in the microcontroller unit of an edge device. Furthermore, resistor–transistor logic, which perform not only windowing using the Hann function, but also acquire audio raw data, is added to the inter-integrated circuit sound module that collects audio data in the voice-recognition application. As a result of the experiment, the windowing function was excluded from the TinyML application of the embedded board. When the length of the hardware-implemented Hann window is 80 and the quantization degree is 2−5, the exclusion causes a decrease in the execution time of the front-end function and energy consumption by 8.06% and 3.27%, respectively

Optimized Replication of ADC-Based Particle Counting Algorithm with Reconfigurable Multi-Variables in Pseudo-Supervised Digital Twining of Reference Dust Sensor Systems

As the application fields for digital twins have expanded, various studies have been conducted with the objective of optimizing the costs. Among these studies, research on low-power and low-performance embedded devices has been implemented at a low cost by replicating the performance of existing devices. In this study, we attempt to obtain similar particle count results in a single-sensing device replicated from the particle count results in a multi-sensing device without knowledge of the particle count acquisition algorithm of the multi-sensing device. Through filtering, we suppressed the noise and baseline movements of the raw data of the device. In addition, in the process of determining the multi-threshold for obtaining the particle counts, the existing complex particle count determination algorithm was simplified to make it possible to utilize the look-up table. The proposed simplified particle count calculation algorithm reduced the optimal multi-threshold search time by 87% on average and the root mean square error by 58.5% compared to existing method. In addition, it was confirmed that the distribution of particle count from optimal multi-thresholds has a similar shape to that from multi-sensing devices

Aziridine-Capped Poly(ethylene glycol) Brush Copolymers with Tunable Architecture as Versatile Cross-Linkers for Adhesives

Controlling adhesive and cohesive properties in a refined manner is paramount to developing high-performance adhesives. Therefore, developing and implementing cross-linkers have become a major focus in adhesive research, but most conventional cross-linkers are small molecules or oligomers with limited functionality. Herein, a brush copolymer consisting of varying lengths and densities of the aziridine-capped poly(ethylene glycol) (AzPEG) brush, termed P(AzPEG), is presented for use as a multifunctional polymeric cross-linker for carboxylate-containing acrylic adhesives. The density and length of the AzPEG brush, with respect to the total brush, are controlled conveniently by the concentration and molecular weight of the AzPEG acrylate monomer, respectively. In addition, the use of amphiphilic PEG also makes it possible for use in a variety of solvents. Using poly(EHA-co-AA) and poly(EHA-co-BA-co-MMA-co-AA-co-HEMA) as solvent and waterborne acrylic adhesives, respectively, their mechanical and adhesive properties are effectively controlled by P(AzPEG) with varying densities and lengths of the AzPEG brush without the need for a substantial change in concentration. These findings certainly show the advantages of brush copolymer-based cross-linkers for adhesives

Runtime Tracking-Based Replication of On-Chip Embedded Software Using Transfer Function Learning for Dust Particle Sensing Systems

A digital twin is a widely used method that uses digitized simulations of the real-world characteristics because it is effective in predicting results at a low cost. In digital twin analysis, the transfer function between the input and output data is an important research subject. In this study, we intend to investigate the application of the digital twin method to dust particle sensing. A high-performance multi-channel reference dust particle sensor provides particle count as well as particulate matter information, whereas a lightweight embedded test device only provides a particle count. The particulate matter acquisition algorithm for a reference device is unknown and complex. Instead of that, we propose a simple method to calculate the transfer function using singular-value decomposition. In the experimental results, using singular-value decomposition, the predicted particulate matter of the test device was similar to that of the reference device. The obtained transfer function shows similar measurement results of the two dust particle sensor devices, confirming that particulate matter environmental information can be digitized even with low-power and lightweight sensor-embedded devices. In addition, the power consumption of the test device was approximately ten times lower than that of the reference device

P-51 Instrumentation Strategy for Mobile Phone Based ECL Biosensor

As mobile technology continues to advance, it possesses advantageous characteristics (e.g. universality and versatility). The goal of this research is to develop an electrochemiluminescence (ECL) immunosensor that is powered and operated by a mobile device. The biosensor consists of a screen-printed electrode, and uses the mobile device camera to capture the visible ECL reaction. We have developed a finalized electronic circuit that alters the audiojack voltage of the mobile device, supplying power to the biosensor. Currently, we are developing a mobile application, and assembling a marketable prototype. This device has potential applications in education, research, and medical diagnosis

Excluded vertex-minors for graphs of linear rank-width at most k

Linear rank-width is a graph width parameter, which is a variation of rank-width by restricting its tree to a caterpillar. As a corollary of known theorems, for each $k$, there is a finite obstruction set $\mathcal{O}_k$ of graphs such that a graph $G$ has linear rank-width at most $k$ if and only if no vertex-minor of $G$ is isomorphic to a graph in $\mathcal{O}_k$. However, no attempts have been made to bound the number of graphs in $\mathcal{O}_k$ for $k\ge 2$. We show that for each $k$, there are at least $2^{\Omega(3^k)}$ pairwise locally non-equivalent graphs in $\mathcal{O}_k$, and therefore the number of graphs in $\mathcal{O}_k$ is at least double exponential. To prove this theorem, it is necessary to characterize when two graphs in $\mathcal O_k$ are locally equivalent. A graph is a block graph if all of its blocks are complete graphs. We prove that if two block graphs without simplicial vertices of degree at least $2$ are locally equivalent, then they are isomorphic. This not only is useful for our theorem but also implies a theorem of Bouchet [Transforming trees by successive local complementations, J. Graph Theory 12 (1988), no. 2, 195-207] stating that if two trees are locally equivalent, then they are isomorphic.Comment: 19 pages, 8 figures. An extended abstract appeared in Proc. 30th International Symposium on Theoretical Aspects of Computer Science, 2013 (STACS2013