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All Topic Review Biography
Topic Review
Bluetooth Low Energy Mesh Networks
Bluetooth Low Energy (BLE) is an increasingly prevalent Wireless Ad-Hoc Network (WAHN) technology for battery-powered Internet of Things (IoT) devices [1]. The BLE standard was introduced by the Bluetooth Special Interest Group (SIG) in Bluetooth version 4.0, and subsequently enhanced in versions 4.2 and 5. Initially, BLE 4.x adopted the legacy Bluetooth Personal Area Network (PAN) model for multi-hop communications and the interconnection of networks. BLE 5 intends to address these inadequacies via the implementation of pure mesh topology to provide enhanced network coverage, inter-network connectivity, and improved security [2].
  • 1.8K
  • 28 Oct 2020
Topic Review
Indian Regional Navigation Satellite System
The Indian Regional Navigation Satellite System (IRNSS), with an operational name of NAVIC (acronym for NAVigation with Indian Constellation; also, nāvik 'sailor' or 'navigator' in Sanskrit, Hindi, and many other Indian languages), is an autonomous regional satellite navigation system that provides accurate real-time positioning and timing services. It covers India and a region extending 1,500 km (930 mi) around it, with plans for further extension. An extended service area lies between the primary service area and a rectangle area enclosed by the 30th parallel south to the 50th parallel north and the 30th meridian east to the 130th meridian east, 1,500–6,000 km (930–3,730 mi) beyond borders. The system currently consists of a constellation of seven satellites, with two additional satellites on ground as stand-by. The constellation is in orbit as of 2018, and the system was expected to be operational from early 2018 after a system check. NAVIC will provide two levels of service, the "standard positioning service", which will be open for civilian use, and a "restricted service" (an encrypted one) for authorised users (including the military). NAVIC is planned to become available for civilian use in the first half of 2020. There are plans to expand the NAVIC system by increasing its constellation size from 7 to 11.
  • 1.8K
  • 12 Oct 2022
Topic Review
Semaphore Line
A semaphore telegraph is a system of conveying information by means of visual signals, using towers with pivoting shutters, also known as blades or paddles. Information is encoded by the position of the mechanical elements; it is read when the shutter is in a fixed position. The most widely used system was invented in 1792 in France by Claude Chappe, and was popular in the late eighteenth to early nineteenth centuries. Lines of relay towers with a semaphore rig at the top were built within line-of-sight of each other, at separations of 5 to 20 miles. Operators at each tower would watch the neighboring tower through a spyglass, and when the semaphore arms began to move spelling out a message. They would pass the message on to the next tower. This system was much faster than post riders for conveying a message over long distances, and also had cheaper long-term operating costs, once constructed. Semaphore lines were a precursor of the electrical telegraph, which would replace them half a century later, and would also be cheaper, faster, and more private. The line-of-sight distance between relay stations was limited by geography and weather, and prevented the optical telegraph from crossing wide expanses of water, unless a convenient island could be used for a relay station. Modern derivatives of the semaphore system include flag semaphore (a flag relay system) and the heliograph (optical telegraphy using mirror-directed sunlight reflections).
  • 1.8K
  • 20 Oct 2022
Topic Review
AI Public Datasets for Railway Applications
The aim of this entry is to review existing publicly available and open artificial intelligence (AI) oriented datasets in different domains and subdomains of the railway sector. The contribution of this paper is an overview of AI-oriented railway data published under Creative Commons (CC) or any other copyright type that entails public availability and freedom of use. These data are of great value for open research and publications related to the application of AI in the railway sector.
  • 1.8K
  • 09 Oct 2021
Topic Review
Radioactive Waste Containing Graphite Management
Since the beginning of the nuclear industry, graphite has been widely used as a moderator and reflector of neutrons in nuclear power reactors. Some reactors are relatively old and have already been shut down. As a result, a large amount of irradiated graphite has been generated. Although several thousand papers in the International Nuclear Information Service (INIS) database have discussed the management of radioactive waste containing graphite, knowledge of this problem is not common.
  • 1.8K
  • 17 Sep 2020
Topic Review
Dugout Canoe
A dugout canoe or simply dugout is a boat made from a hollowed tree. Other names for this type of boat are logboat and monoxylon. Monoxylon (μονόξυλον) (pl: monoxyla) is Greek -- mono- (single) + ξύλον xylon (tree) -- and is mostly used in classic Greek texts. In German, they are called Einbaum ("one tree" in English). Some, but not all, pirogues are also constructed in this manner. Dugouts are the oldest boat type archaeologists have found, dating back about 8,000 years to the Neolithic Stone Age. This is probably because they are made of massive pieces of wood, which tend to preserve better than, e.g., bark canoes. Along with bark canoe and hide kayak, dugout boats were also used by indigenous peoples of the Americas.
  • 1.8K
  • 25 Oct 2022
Topic Review
Daihatsu Rocky
The Daihatsu Rocky (Japanese: ダイハツ・ロッキー, Daihatsu Rokkī) is an automobile nameplate used by Daihatsu for their lineup of SUVs. The nameplate was originally used as a ladder frame-based mini SUV that was sold in Japan and some international markets between 1989 and 2002. It was gradually replaced by the introduction of Terios in 1997. Beginning in 2019, the Rocky nameplate returned to Japan as a subcompact crossover SUV that replaces the Be‣go and is also rebadged and sold under Toyota brand as the Toyota Raize (Japanese: トヨタ・ライズ, Toyota Raizu).
  • 1.8K
  • 27 Oct 2022
Topic Review
Low-Cost 3D Laser Scanning Technology
By moving a commercial 2D LiDAR, 3D maps of the environment can be built, based on the data of a 2D LiDAR and its movements. Compared to a commercial 3D LiDAR, a moving 2D LiDAR is more economical. A series of problems need to be solved in order for a moving 2D LiDAR to perform better, among them, improving accuracy and real-time performance. In order to solve these problems, estimating the movements of a 2D LiDAR, and identifying and removing moving objects in the environment, are issues that should be studied.
  • 1.8K
  • 03 Jun 2021
Topic Review
Parabolic Aluminized Reflector Light
A parabolic aluminized reflector lamp (also PARCAN light, PARcan, or simply PAR) is a type of electric lamp that is widely used in commercial, residential, and transportation illumination. Usage includes locomotive headlamps, aircraft landing lights, and residential and commercial recessed lights ("cans" in the United States). They are identical in principle to sealed beam automobile headlights. The lamps and their fixtures are widely used in theatre, concerts and motion picture production when a substantial amount of flat lighting is required for a scene. In situations where sunlight or other specular light is available, a white foam reflector is often used to accomplish the same effect as a PAR array. PAR cans are being replaced in some stage applications by LED PAR cans, which use less electric power and produce a wide array of saturated colors without the use of color filters, when white light is not needed.
  • 1.8K
  • 18 Oct 2022
Topic Review
Hybrid Convolutional Neural Network–Bidirectional Long Short-Term Memory
Recognition of lying is a more complex cognitive process than truth-telling because of the presence of involuntary cognitive cues that are useful to lie recognition. Researchers have proposed different approaches in the literature to solve the problem of lie recognition from either handcrafted and/or automatic lie features during court trials and police interrogations.
  • 1.8K
  • 09 Apr 2024
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