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Topic Review
Blockchain-Based Financial Tools
Blockchain technology has had a close connection with finance since the beginning. It is well known that one of the main success story for blockchain is Bitcoin, the first cryptocurrency. Beside the original novelty of implementing transactions in a decentralized setting, it is now clear that blockchains enable a wide range of novel financial instruments, many of which are specific of blockchain-based economic systems.
  • 547
  • 13 May 2022
Topic Review
IEEE 802.11ax
IEEE 802.11ax, marketed as Wi-Fi 6 by Wi-Fi Alliance, is a draft Wi-Fi specification standard, and the proposed successor to Wi-Fi 5. The 802.11ax standard is expected to become an official IEEE specification in September 2020. It is designed to operate in licensed exempt bands between 1 and 6 GHz when they become available for 802.11 use. All Wi-Fi 6 devices work over the previously allocated 2.4 and 5 GHz bands. The Wi-Fi 6E designation is for products that also support the standard over 6 GHz. Devices presented at CES 2018 claimed a combined 11 Gbit/s of theoretical data rates. For dense deployments, throughput speeds are 4× higher than IEEE 802.11ac, even though the nominal data rate is just 37% faster at most. Latency is also down 75%. To improve spectrum efficient utilization, the new version introduces better power-control methods to avoid interference with neighboring networks, orthogonal frequency-division multiple access (OFDMA), higher order 1024-QAM, and up-link direction added with the down-link of MIMO and MU-MIMO to further increase throughput, as well as dependability improvements of power consumption and security protocols such as Target Wake Time and WPA3.
  • 547
  • 17 Oct 2022
Topic Review
Loco2
Loco2, now rebranded as Rail Europe, is an online booking service for train travel in the United Kingdom and Europe. It sells tickets through its website and via its smartphone app which is available on iOS and Android platforms. It was founded in 2006 by brother and sister Jamie and Kate Andrews, and started trading in 2012 from its headquarters in London. Loco2 website and apps were rebranded Rail Europe in November 2019.
  • 547
  • 19 Oct 2022
Topic Review
Non-Standard Analysis
The history of calculus is fraught with philosophical debates about the meaning and logical validity of fluxions or infinitesimal numbers. The standard way to resolve these debates is to define the operations of calculus using epsilon–delta procedures rather than infinitesimals. Non-standard analysis instead reformulates the calculus using a logically rigorous notion of infinitesimal numbers. Non-standard analysis was originated in the early 1960s by the mathematician Abraham Robinson. He wrote: "... the idea of infinitely small or infinitesimal quantities seems to appeal naturally to our intuition. At any rate, the use of infinitesimals was widespread during the formative stages of the Differential and Integral Calculus. As for the objection ... that the distance between two distinct real numbers cannot be infinitely small, Gottfried Wilhelm Leibniz argued that the theory of infinitesimals implies the introduction of ideal numbers which might be infinitely small or infinitely large compared with the real numbers but which were to possess the same properties as the latter". Robinson argued that this law of continuity of Leibniz's is a precursor of the transfer principle. Robinson continued: "However, neither he nor his disciples and successors were able to give a rational development leading up to a system of this sort. As a result, the theory of infinitesimals gradually fell into disrepute and was replaced eventually by the classical theory of limits." "It is shown in this book that Leibniz's ideas can be fully vindicated and that they lead to a novel and fruitful approach to classical Analysis and to many other branches of mathematics. The key to our method is provided by the detailed analysis of the relation between mathematical languages and mathematical structures which lies at the bottom of contemporary model theory." In 1973, intuitionist Arend Heyting praised non-standard analysis as "a standard model of important mathematical research".
  • 547
  • 17 Nov 2022
Topic Review
Wireless Sensor Networks with Mobile Sink
With the advances in sensing technologies, sensor networks became the core of several different networks, including the Internet of Things (IoT) and drone networks. This led to the use of sensor networks in many critical applications including military, health care, and commercial applications.
  • 547
  • 05 Jan 2023
Topic Review
Deepfake Identification and Traceability
Researchers and companies have released multiple datasets of face deepfakes labeled to indicate different methods of forgery. Naming these labels is often arbitrary and inconsistent. However, researchers must use multiple datasets in practical applications to conduct traceability research. The researchers utilize the K-means clustering method to identify datasets with similar feature values and analyze the feature values using the Calinski Harabasz Index method. Datasets with the same or similar labels in different deepfake datasets exhibit different forgery features. The KCE system can solve this problem, which combines multiple deepfake datasets according to feature similarity. In the model trained based on KCE combined data, the Calinski Harabasz scored 42.3% higher than the combined data by the same forgery name. It shows that this method improves the generalization ability of the model.
  • 547
  • 08 Jun 2023
Topic Review
Boundary Conditions, Nonequilibrium Thermodynamics Equations
In this entry, we present a systematical review on boundary conditions (BCs) for partial differential equations (PDEs) from nonequilibrium thermodynamics. From a stability point of view, such PDEs should satisfy the structural stability condition. In particular, they constitute hyperbolic systems, for which the generalized Kreiss condition (UKC) is a sufficient and essentially necessary condition for the well-posedness of the corresponding models (PDEs with BCs).
  • 546
  • 08 Oct 2021
Topic Review
React (Web Framework)
React (also known as React.js or ReactJS) is an open-source JavaScript library for building user interfaces. It is maintained by Facebook and a community of individual developers and companies. React can be used as a base in the development of single-page or mobile applications. However, React is only concerned with rendering data to the DOM, and so creating React applications usually requires the use of additional libraries for state management and routing. Redux and React Router are respective examples of such libraries.
  • 546
  • 10 Oct 2022
Topic Review
Colord
Linux color management has the same goal as the color management systems (CMS) for other operating systems: to achieve the best possible color reproduction throughout an imaging workflow from its source (camera, video, scanner, etc.), through imaging software (Digikam, darktable, RawTherapee, GIMP, Krita, Scribus, etc.), and finally onto an output medium (monitor, video projector, printer, etc.). In particular, color management attempts to enable color consistency across media and throughout a color-managed workflow. Linux color management relies on the use of accurate ICC (International Color Consortium) and DCP (DNG Color Profile) profiles describing the behavior of input and output devices, and color-managed applications that are aware of these profiles. These applications perform gamut conversions between device profiles and color spaces. Gamut conversions, based on accurate device profiles, are the essence of color management. Historically, color management was not an initial design consideration of the X Window System on which much of Linux graphics support rests, and thus color-managed workflows have been somewhat more challenging to implement on Linux than on other OS's such as Microsoft Windows or macOS. This situation is now being progressively remedied, and color management under Linux, while functional, has not yet acquired mature status. Although it is now possible to obtain a consistent color-managed workflow under Linux, certain problems still remain: Since ICC color profiles are written to an open specification, they are compatible across operating systems. Hence, a profile produced on one OS should work on any other OS given the availability of the necessary software to read it and perform the gamut conversions. This can be used as a workaround for the lack of support for certain spectrophotometers or colorimeters under Linux: one can simply produce a profile on a different OS and then use it in a Linux workflow. Additionally, certain hardware, such as most printers and certain monitors, can be calibrated under another OS and then used in a fully color-managed workflow on Linux. The popular Ubuntu Linux distribution added initial color management in the 11.10 release (the "Oneiric Ocelot" release).
  • 546
  • 06 Nov 2022
Topic Review
Transporting Blood Using Unmanned Aerial Vehicles
Unmanned Aerial Vehicles (UAVs) play crucial roles in numerous applications, such as healthcare services. For example, UAVs can help in disaster relief and rescue missions, such as by delivering blood samples and medical supplies.
  • 546
  • 21 Nov 2022
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