Electrical field modelling of transcranial direct current stimulation

Abstract. Transcranial Direct Current Stimulation (tDCS) is a technology for neurotransmission that provides direct current to relatively intensive cortical areas in order to modulate internal brain activity. There have been inaccuracies in tDCS findings identified by recent studies. In this study, we present a modeling pipeline for computer-based tDCS analysis for studying different electrode montages and different sizes (1 x 6 cm²) and (5 x 7 cm²) of electrodes to find out the outcomes. The assumption is that a given brain region’s stimulation would be stable in different montages. The total simulation current flow and electric field distribution within the brain were determined for the four most widely used tDCS montages: F3-F4, F3-FP2, FP1-FP2, and C4-FP2, using the COMETS2 software tool. The effect of the size of the electrodes is simulated for tDCS in F3-FP2 mounts in small (1 x 6 cm²) and wide (5 x 7 cm²) rectangular electrodes. The current flow is calculated in order to examine the impact of the mounting setup for current density and electric field. Regional as well as localized current densities in the electrode sites have been considered for each of the various mounting setups

Volume 29- Issue 10- Friday, December 3, 1993

The Rose Thorn, Rose-Hulman\u27s independent student newspaper.https://scholar.rose-hulman.edu/rosethorn/1549/thumbnail.jp

Radar Technology

In this book “Radar Technology”, the chapters are divided into four main topic areas: Topic area 1: “Radar Systems” consists of chapters which treat whole radar systems, environment and target functional chain. Topic area 2: “Radar Applications” shows various applications of radar systems, including meteorological radars, ground penetrating radars and glaciology. Topic area 3: “Radar Functional Chain and Signal Processing” describes several aspects of the radar signal processing. From parameter extraction, target detection over tracking and classification technologies. Topic area 4: “Radar Subsystems and Components” consists of design technology of radar subsystem components like antenna design or waveform design

The document/book as a form of curatorial creativity

This thesis discusses the document/book as an act of recording that can serve as a form for curatorial creativity. Firstly, it explores the document as a space in a hybrid analog and digital era. Then, it introduces concrete examples of how curating the gallery and the book has changed in the 20th and 21st centuries. It follows a critical analysis of society as one big accumulation of documents. It proposes the invention of writing as the base of our current digital spaces and the space of the book as architecture. In respect to the curatorial discourse, it focuses on Springer's proposition of engaging with the library in order to develop new ways of organizing, collecting, and reassembling information. The first chapter introduces Benjamin Bratton's diagram of "The Stack", which serves to explore the physical spaces of information, describing how the infrastructure of books has come to expand significantly from clay to paper, and now to the Cloud. It proposes the codex-book, a stack of paper sheets as an analogy of the stack through the example of artist Irfan Hendrian "Some Other Matter" exhibition. It also proposes the page—a place of inventory and invention— as the first virtual space of humanity. The second chapter discusses the library's primary functions of storage and retrievability —proposing the Library of Alexandria as the first information organization. Then comes back to an example of how the old model of the library can be used for creating a new display for the gallery as well as giving value to its collection through physical activation. Finally, it explores some of the invisible systems (covers, algorithms, tags) that are now building our digital libraries. The third chapter focuses on copy and print as essential tools for recording, preservation, and building collections. It introduces the history of mass digitization and the changes it has brought to analog documents. It also explores the space of digital and print through Kenneth Goldsmith's curatorial project that called out to print out all the internet. This example leads us to discuss the history of the A4-size paper sheet as the first completely standardize product. The fourth chapter presents the "neutral" containers —starting from the concept of the "gallery-book" proposed by Bernard Teyssendier as a place of movement, pleasure, and learning. It also explores architecture and design as curatorial infrastructure for exhibitions happening both in a gallery space and on a blank document. Finally, it creates a parallel between the white paper page and the white gallery wall as places of artistic intervention, which far from being invisible follow specific predefined structures. The fifth chapter focuses on presenting projects that propose new curated writing and reading contexts between the print and digital. Here, Brian O'Doherty's issue for "Aspen" magazine is proposed as proto-hypertext or as a premonition of the website. Then, the website-as-gallery concept is explored through the example of Kadist's "One Sentence Exhibition" project. This example leads to exploring the fragility and impermanence of the hyperlink, in contrast to its printed counterparts. The final chapter presents three projects that use the infrastructure of the book and the library as a curatorial agency —proposing new methods for curating information through collection, organization, and research. "Intercalations", a paginated exhibition series by Anna-Sophie Springer and Etienne Turpin; "MAP", a folded encyclopedia by the David A. Garcia architecture studio; and "Carte(s) Mémoire(s)" by ExposerPublier that proposes the exhibition as a moment of activation

Multi-node TOA-DOA cooperative LOS-NLOS localization : enabling high accuracy and reliability

This dissertation investigates high performance cooperative localization in wireless environments based on multi-node time-of-arrival (TOA) and direction-of-arrival (DOA) estimations in line-of-sight (LOS) and non-LOS (NLOS) scenarios. Here, two categories of nodes are assumed: base nodes (BNs) and target nodes (TNs). BNs are equipped with antenna arrays and capable of estimating TOA (range) and DOA (angle). TNs are equipped with Omni-directional antennas and communicate with BNs to allow BNs to localize TNs; thus, the proposed localization is maintained by BNs and TNs cooperation. First, a LOS localization method is proposed, which is based on semi-distributed multi-node TOA-DOA fusion. The proposed technique is applicable to mobile ad-hoc networks (MANETs). We assume LOS is available between BNs and TNs. One BN is selected as the reference BN, and other nodes are localized in the coordinates of the reference BN. Each BN can localize TNs located in its coverage area independently. In addition, a TN might be localized by multiple BNs. High performance localization is attainable via multi-node TOA-DOA fusion. The complexity of the semi-distributed multi-node TOA-DOA fusion is low because the total computational load is distributed across all BNs. To evaluate the localization accuracy of the proposed method, we compare the proposed method with global positioning system (GPS) aided TOA (DOA) fusion, which are applicable to MANETs. The comparison criterion is the localization circular error probability (CEP). The results confirm that the proposed method is suitable for moderate scale MANETs, while GPS-aided TOA fusion is suitable for large scale MANETs. Usually, TOA and DOA of TNs are periodically estimated by BNs. Thus, Kalman filter (KF) is integrated with multi-node TOA-DOA fusion to further improve its performance. The integration of KF and multi-node TOA-DOA fusion is compared with extended-KF (EKF) when it is applied to multiple TOA-DOA estimations made by multiple BNs. The comparison depicts that it is stable (no divergence takes place) and its accuracy is slightly lower than that of the EKF, if the EKF converges. However, the EKF may diverge while the integration of KF and multi-node TOA-DOA fusion does not; thus, the reliability of the proposed method is higher. In addition, the computational complexity of the integration of KF and multi-node TOA-DOA fusion is much lower than that of EKF. In wireless environments, LOS might be obstructed. This degrades the localization reliability. Antenna arrays installed at each BN is incorporated to allow each BN to identify NLOS scenarios independently. Here, a single BN measures the phase difference across two antenna elements using a synchronized bi-receiver system, and maps it into wireless channel’s K-factor. The larger K is, the more likely the channel would be a LOS one. Next, the K-factor is incorporated to identify NLOS scenarios. The performance of this system is characterized in terms of probability of LOS and NLOS identification. The latency of the method is small. Finally, a multi-node NLOS identification and localization method is proposed to improve localization reliability. In this case, multiple BNs engage in the process of NLOS identification, shared reflectors determination and localization, and NLOS TN localization. In NLOS scenarios, when there are three or more shared reflectors, those reflectors are localized via DOA fusion, and then a TN is localized via TOA fusion based on the localization of shared reflectors

Mathematics Yearbook 2021

The Deakin University Mathematics Yearbook publishes student reports and articles in all areas of mathematics with an aim of promoting interest and engagement in mathematics and celebrating student achievements. The 2021 edition includes 7 coursework articles, where students have extended upon submissions in their mathematics units, as well as 4 articles based on student research projects conducted throughout 2020 and 2021