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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 ... [...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 (journal), Cell'', the ScienceDirect collection of electronic journals, ''Trends (journals), Trends'', the ''Current Opinion (Elsevier), 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 include digital tools for Data management platform, 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 2022 Elsevier published more than 600,000 articles annually in over 2,800 journals. As of 2018, its archives contained over 17 million documents and 40,000 Ebook, e-books, with over one b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discrete Cosine Transform
A discrete cosine transform (DCT) expresses a finite sequence of data points in terms of a sum of cosine functions oscillating at different frequency, frequencies. The DCT, first proposed by Nasir Ahmed (engineer), Nasir Ahmed in 1972, is a widely used transformation technique in signal processing and data compression. It is used in most digital media, including digital images (such as JPEG and HEIF), digital video (such as MPEG and ), digital audio (such as Dolby Digital, MP3 and Advanced Audio Coding, AAC), digital television (such as SDTV, HDTV and Video on demand, VOD), digital radio (such as AAC+ and DAB+), and speech coding (such as AAC-LD, Siren (codec), Siren and Opus (audio format), Opus). DCTs are also important to numerous other applications in science and engineering, such as digital signal processing, telecommunication devices, reducing network bandwidth usage, and spectral methods for the numerical solution of partial differential equations. A DCT is a List of Fourier ... [...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). A Fourier transform 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 Matrix decomposition, factorizing the DFT matrix into a product of Sparse matrix, sparse (mostly zero) factors. As a result, it manages to reduce the Computational complexity theory, complexity of computing the DFT from O(n^2), which arises if one simply applies the definition of DFT, to O(n \log n), where is the data size. The difference in speed can be enormous, especially for long data sets where may be in the thousands or millions. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chubb Locks
Chubb Locks is a former brand name of the Mul-T-Lock subsidiary of the Assa Abloy Group, which manufactures locking systems for residential, secure confinement and commercial applications. When the brand licence expired in 2010 the name ceased to be used, with the same locks sold as Yale or Union locks. 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, still known today 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 King George IV, and later became the sole supplier of locks to the General Post Office (GPO), and a supplier to His Majesty's Prison Service. In 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yale (company)
Yale is a lock manufacturer and a subsidiary of Assa Abloy, except in the United States and Canada where the brand has been owned by Fortune Brands Innovations since 2023. The global company is headquartered in Stockholm, Sweden. Its initial product was the Yale lock, invented by Linus Yale Sr., and it became the foundation of the enterprise founded by Linus Yale Jr. and Henry R. Towne. Its markets were initially in the United States, and expanded across the globe during the Industrial Revolution, with a workforce of over 12,000 employees. History Yale & Towne Manufacturing Co, 1897 In 1868, the business was established in Stamford, Connecticut, by Henry R. Towne and Linus Yale Sr., an inventor renowned for creating the pin tumbler lock. Initially known as Yale Lock Manufacturing Co., the company later adopted the name Yale & Towne, with its base in Newport, New York. Between 1843 and 1857, Yale secured eight patents, encompassing items like the pin tumbler safe lock ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burglar Alarm
A security alarm is a system designed to detect intrusions, such as unauthorized entry, into a building or other areas, such as a home or school. Security alarms protect against burglary (theft) or property damage, as well as against intruders. Examples include personal systems, neighborhood security alerts, car alarms, and prison alarms. Some alarm systems serve a single purpose of burglary protection; combination systems provide Fire alarm system, 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 complicated, multirole systems with computer and network surveillance, computer monitoring and control. It may even include a two-way voice which allows communication between the pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perimeter Security
Perimeter security refers to natural barriers or constructed fortifications designed either to prevent intruders from entering an area or to contain individuals within an enclosed area. 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 attackers. 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 Hadrian's Wall in the Roma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass Engineering And Science
Glass is an amorphous ( non-crystalline) solid. Because it is often transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window panes, tableware, and optics. Some common objects made of glass are named after the material, e.g., a "glass" for drinking, "glasses" for vision correction, and a "magnifying glass". Glass is most often formed by rapid cooling (quenching) of the molten form. Some glasses such as volcanic glass are naturally occurring, and obsidian has been used to make arrowheads and knives since the Stone Age. Archaeological evidence suggests glassmaking dates back to at least 3600 BC in Mesopotamia, Ancient Egypt, Egypt, or Syria. The earliest known glass objects were beads, perhaps created accidentally during metalworking or the production of faience, which is a form of pottery using lead glazes. Due to its ease of formability into any shape, glass has been traditionally used for vessels, such as bowl (ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
