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Glass Break Detector
A glass break detector is a sensor that detects if a pane of glass has been shattered or broken. These sensors are commonly used near glass doors or glass storefront windows. They are widely used in electronic burglar-alarm systems. The detection process begins with a microphone that picks up noises and vibrations coming from the glass. If the vibrations exceed a certain threshold (which is sometimes user selectable), then they are analyzed by detector circuitry. Simpler detectors merely use narrowband microphones tuned to frequencies typical of glass shattering. These are merely designed to react to sound magnitudes above a certain threshold, whereas more complex designs analytically compare the sound to one or more glass-break profiles using signal transforms similar to DCT and FFT. These digitally sophisticated detectors only react if both the amplitude threshold and statistically expressed similarity threshold are breached. Advances in technology have also led to the use o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elsevier
Elsevier () is a Dutch academic publishing company specializing in scientific, technical, and medical content. Its products include journals such as ''The Lancet'', ''Cell'', the ScienceDirect collection of electronic journals, '' Trends'', the '' Current Opinion'' series, the online citation database Scopus, the SciVal tool for measuring research performance, the ClinicalKey search engine for clinicians, and the ClinicalPath evidence-based cancer care service. Elsevier's products and services also include digital tools for data management, instruction, research analytics and assessment. Elsevier is part of the RELX Group (known until 2015 as Reed Elsevier), a publicly traded company. According to RELX reports, in 2021 Elsevier published more than 600,000 articles annually in over 2,700 journals; as of 2018 its archives contained over 17 million documents and 40,000 e-books, with over one billion annual downloads. Researchers have criticized Elsevier for its high profit marg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fast Fourier Transform
A fast Fourier transform (FFT) is an algorithm that computes the discrete Fourier transform (DFT) of a sequence, or its inverse (IDFT). Fourier analysis converts a signal from its original domain (often time or space) to a representation in the frequency domain and vice versa. The DFT is obtained by decomposing a sequence of values into components of different frequencies. This operation is useful in many fields, but computing it directly from the definition is often too slow to be practical. An FFT rapidly computes such transformations by factorizing the DFT matrix into a product of sparse (mostly zero) factors. As a result, it manages to reduce the complexity of computing the DFT from O\left(N^2\right), which arises if one simply applies the definition of DFT, to O(N \log N), where N is the data size. The difference in speed can be enormous, especially for long data sets where ''N'' may be in the thousands or millions. In the presence of round-off error, many FFT algorithm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chubb Locks
Chubb Locks is a former brand name (expired 2010) of the Mul-T-Lock subsidiary of the Assa Abloy Group, which manufactures locking systems for residential, secure confinement and commercial applications. History Chubb was started as a ship's ironmonger by Charles Chubb in Winchester, England, and then moved to Portsmouth, England, in 1804. Chubb moved the company into the locksmith business in 1818, in Wolverhampton. The company worked out of a number of premises in Wolverhampton, including the purpose-built factory on Railway Street, now still known as the Chubb Building. His brother Jeremiah Chubb then joined the company, and they sold Jeremiah's patented detector lock. In 1823, the company was awarded a special licence by George IV, and later became the sole supplier of locks to the General Post Office, and a supplier to Her Majesty's Prison Service. In 1835, they received a patent for a burglar-resisting safe, and opened a safe factory in London in 1837. In 1851, they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yale (company)
Yale is one of the world's oldest lock manufacturers, owned by its parent company, Assa Abloy. Over its extensive history, Yale has received patents for dozens of its products, and the company has distributed its products to more than 120 countries, including Australia, Greece, India, Kuwait, and others. Yale's headquarters are located in Stockholm, Sweden. History In 1868, the business was founded in Stamford, Connecticut, by Henry R. Towne and Linus Yale Jr., an inventor of the pin tumbler lock. The founding name of the corporation was Yale Lock Manufacturing Co. and later the name was changed to Yale & Towne, basing themselves in Newport, New York.. From 1843 to 1857, Yale had registered eight patents, such as pin tumbler safe lock, safe lock, bank lock, vault, safe door bolt and padlock with the U.S. Patent and Trademark Office. Around 1876, they have added the manufacturing of chain blocks, electric hoists, cranes and testing machines, becoming the pioneer of crane b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burglar Alarm
A security alarm is a system designed to detect intrusion, such as unauthorized entry, into a building or other areas such as a home or school. Security alarms used in residential, commercial, industrial, and military properties protect against burglary (theft) or property damage, as well as personal protection against intruders. Security alerts in neighborhoods show a connection with diminished robbery. Car alarms likewise help protect vehicles and their contents. Prisons also use security systems for the control of inmates. Some alarm systems serve a single purpose of burglary protection; combination systems provide fire and intrusion protection. Intrusion-alarm systems are combined with closed-circuit television surveillance (CCTV) systems to record intruders' activities and interface to access control systems for electrically locked doors. There are many types of security systems. Homeowners typically have small, self-contained noisemakers. These devices can also be complica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perimeter Security
Perimeter security refers to natural barriers or built fortifications to either keep intruders out or to keep captives contained within the area the boundary surrounds. Purpose Since at least the Roman Empire, fortifications, walls and barriers have been an important part of protecting sovereign territories and private property. Perimeter security is designed with the primary purpose to either keep intruders out or captives contained within the area the boundary surrounds. Both natural and manmade barriers can serve as perimeter security. Governments use perimeter security not only for the safety of their citizens, but to control the flow of commerce and immigration, as well as to protect vital infrastructure from vandals and terrorists. Property owners and organizations of all sizes use various man-made technology to achieve varying degrees of perimeter security. History One of the earliest known instances of perimeter security on a large scale is that of Hadrian's Wall in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass Engineering And Science
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of the molten form; some glasses such as volcanic glass are naturally occurring. The most familiar, and historically the oldest, types of manufactured glass are "silicate glasses" based on the chemical compound silica (silicon dioxide, or quartz), the primary constituent of sand. Soda–lime glass, containing around 70% silica, accounts for around 90% of manufactured glass. The term ''glass'', in popular usage, is often used to refer only to this type of material, although silica-free glasses often have desirable properties for applications in modern communications technology. Some objects, such as drinking glasses and eyeglasses, are so commonly made of silicate-based glass that they are simply called by the name of the material. Despite bei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
