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Topic Review
Location-Based Service
A location-based service (LBS) is a general term denoting software services which utilize geographic data and information to provide services or information to users. LBS can be used in a variety of contexts, such as health, indoor object search, entertainment, work, personal life, etc. Commonly used examples of location based services include navigation software, social networking services, location-based advertising, and tracking systems. LBS can also include mobile commerce when taking the form of coupons or advertising directed at customers based on their current location. They include personalized weather services and even location-based games. LBS is critical to many businesses as well as government organizations to drive real insight from data tied to a specific location where activities take place. The spatial patterns that location-related data and services can provide is one of its most powerful and useful aspects where location is a common denominator in all of these activities and can be leveraged to better understand patterns and relationships. Banking, surveillance, online commerce, and many weapon systems are dependent on LBS. Access policies are controlled by location data and/or time-of-day constraints, or a combination thereof. As such, an LBS is an information service and has a number of uses in social networking today as information, in entertainment or security, which is accessible with mobile devices through the mobile network and which uses information on the geographical position of the mobile device. This concept of location based systems is not compliant with the standardized concept of real-time locating systems (RTLS) and related local services, as noted in ISO/IEC 19762-5 and ISO/IEC 24730-1. While networked computing devices generally do very well to inform consumers of days old data, the computing devices themselves can also be tracked, even in real-time. LBS privacy issues arise in that context, and are documented below.
  • 2.4K
  • 25 Oct 2022
Topic Review
List of Aircraft (D)
This is a list of aircraft in alphabetical order beginning with 'D'.
  • 2.4K
  • 27 Oct 2022
Topic Review
Bombardier CRJ200
The Bombardier CRJ100 and CRJ200 (formerly known as the Canadair CRJ100 and CRJ200) are a family of regional airliners designed and manufactured by Bombardier. The CRJ had the distinction of marking Canada's entry into the civil jet industry. It was based on the Canadair Challenger business jet. An initial effort to produce an enlarged 36-seat version of the aircraft, known as the Challenger 610E, was terminated during 1981. Shortly after Canadair's privatisation and sale to Bombardier, work on a stretched derivative was reinvigorated; during early 1989, the Canadair Regional Jet program was formally launched. On 10 May 1991, the first of three CRJ100 prototypes conducted its maiden flight. The type first entered service during the following year with its launch customer, Germany airline Lufthansa. The initial variant, the CRJ100, was soon joined by another model, designated as the CRJ200. It was largely identical to the CRJ100, except for the installation of more efficient turbofan engines, which gave the aircraft lower fuel consumption, increased cruise altitude and cruise speed. During the 1990s, various additional versions and models of the type were developed and put into service. During the late 1990s, a substantially enlarged derivative of the airliner, referred to as the CRJ700, was developed; it was soon joined by the even larger CRJ900 and CRJ1000. During 2006, production of both the CRJ100 and CRJ200 came to an end; the majority of produced airliners have remained in revenue service to date. Additionally, several airlines have modernised their fleets to support extended service.
  • 2.4K
  • 27 Oct 2022
Topic Review
Volcanic Eruptions
Volcanic eruptions are considered major (very large) when the Volcanic Explosivity Index (VEI) ≥ 5. The nature of the impacts of a VEI ≥ 5 eruption ranges from the destruction of a city, an entire region, climate disturbances as well as to air travel. Even an eruption with VEI < 5 may also have the potential to modify the environment and landscape particularly in proximal and medial facies, as well as surrounding human societies. The variety of environmental destructions due to volcanic eruption differs from primary (e.g., summit collapse, vegetation burning, death), secondary (e.g., atmospheric cooling, global warming), and tertiary (e.g., flood, famine, disease) effects. It is mostly generated by gas emissions, ashes, lava flow, pyroclastic flow, lahar, debris flow, and landslide which results in local and global impacts.
  • 2.4K
  • 14 Apr 2021
Topic Review Peer Reviewed
Henry II of Trastámara (1366–1367, 1369–1379)
Henry II of Castile, also known as Henry of Trastámara, from the Latin “Tras Tamaris” (or beyond the Tambre River), King of Castile and León (1366–1367, 1369–1379) was the first king of the Trastámara Dynasty. In summary, it was a minor branch of the house of Burgundy (or an “Iberian extension” of it), with presence in the kingdoms of Castile, Aragon, Navarre, and Naples. Most notably, it began playing an essential role in the kingdom of Castile, but after the Compromise of Caspe, its power extended decisively to the kingdom of Aragon (1412). Henry II was the illegitimate son of Alfonso XI and his lover Leonor de Guzmán. He waged a civil war against his stepbrother, Peter I, legitimate heir to the throne, as the son of Alfonso XI and Maria of Portugal, Queen of Castile. Henry’s determination to be recognized as king led him to employ the arts in a campaign to discredit his stepbrother and tarnish his image, portraying himself as a defender of the faith with the right to rule. He built the Royal Chapel (1371) in the main church of Córdoba (today’s Mosque/Cathedral) for the burial of his father and grandfather, Ferdinand IV, in order to underscore his connection to the royal line, and refurbished the Puerta del Perdón (Gate of Forgiveness) in 1377, the main entrance to the church, for use as a dramatic stage for public events. 
  • 2.4K
  • 13 Apr 2022
Topic Review
Nickel-Copper Alloys
Nickel-Copper (Ni-Cu) alloys exhibit simultaneously high strength and toughness (particularly, at cryogenic temperatures), excellent corrosion resistance, and may show good wear resistance. Therefore, they are widely used for manufacturing of (i) structural components of equipment in the chemical, oil, and marine industries, (ii) resistors and contacts in electrical and electronic equipment, (iii) corrosion resistant coatings, and (iv) fuel cells. Processing technologies includes bar forging, plate and tube rolling, wire drawing, heat treatment (for certain alloy compositions), powder and wire arc additive manufacturing, electrodeposition.
  • 2.4K
  • 26 Oct 2020
Topic Review
Mechanical Durability of PEM Fuel Cells
The mechanical durability of PEM fuel cells is a significant barrier to commercializing these systems for stationary and transportation power applications. The performance of a PEM fuel cell or stack is affected pointedly by the degradation of its components materials. Performance degradation is unavoidable, but the degradation rate can be minimized by comprehensively understanding degradation and failure mechanisms. Furthermore, the degradation processes of the different components are often interconnected in fuel cells. Therefore, the degradation phenomena of each fuel cell component must be separated, analyzed, and systematically understood to develop novel component materials and build novel cells/stacks that mitigate insufficient fuel cell mechanical durability.
  • 2.4K
  • 01 Aug 2022
Topic Review
High Frequency Active Auroral Research Program
The High Frequency Active Auroral Research Program (HAARP) was initiated as an ionospheric research program jointly funded by the United States Air Force , the U.S. Navy, the University of Alaska Fairbanks, and the Defense Advanced Research Projects Agency (DARPA). It was designed and built by BAE Advanced Technologies (BAEAT). Its original purpose was to analyze the ionosphere and investigate the potential for developing ionospheric enhancement technology for radio communications and surveillance. As a university-owned facility, HAARP is a high-power, high-frequency transmitter used for study of the ionosphere. The most prominent instrument at HAARP is the Ionospheric Research Instrument (IRI), a high-power radio frequency transmitter facility operating in the high frequency (HF) band. The IRI is used to temporarily excite a limited area of the ionosphere. Other instruments, such as a VHF and a UHF radar, a fluxgate magnetometer, a digisonde (an ionospheric sounding device), and an induction magnetometer, are used to study the physical processes that occur in the excited region. Work on the HAARP facility began in 1993. The current working IRI was completed in 2007; its prime contractor was BAE Systems Advanced Technologies. As of 2008, HAARP had incurred around $250 million in tax-funded construction and operating costs. In May 2014, it was announced that the HAARP program would be permanently shut down later in the year. After discussions between the parties, ownership of the facility and its equipment was transferred to the University of Alaska Fairbanks in August 2015. HAARP is a target of conspiracy theorists, who claim that it is capable of "weaponizing" weather. Commentators and scientists say that advocates of this theory are uninformed, as claims made fall well outside the abilities of the facility, if not the scope of natural science.
  • 2.4K
  • 21 Nov 2022
Topic Review
Plant Growth Promoting Bacteria (PGPB)
The salinization of soils is the main threat of agriculture, it affects a large area every year. thus, instead of chemical buffers, bacteria are suggested as an effective solution. In addition, bacteria promoting plant growth are in fact known as a potential alternative to restore, promote and protect crops.
  • 2.4K
  • 27 Oct 2020
Topic Review
Xiaomi Redmi Note 4
The Xiaomi Redmi Note 4 is the fourth smartphone of Redmi Note series developed by Xiaomi Inc. It is a part of Xiaomi's budget Redmi smartphone line. It has two variants: The older version sold as Redmi Note 4 is powered by a Deca-core Mediatek MT6797 Helio X20 SOC. The upgraded version, sold both as Redmi Note 4X and Redmi Note 4 (where MTK version was not released) is powered by an Octa-core MSM8953 Qualcomm Snapdragon 625 SoC. The Redmi Note 4 was succeeded by Redmi Note 5.
  • 2.4K
  • 26 Oct 2022
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