Chubb Locks is a brand name of the Mul-T-Lock subsidiary of the Assa Abloy Group, which manufactures high security locking systems for residential, secure confinement and commercial applications. Chubb was started as a ship's ironmonger by Charles Chubb in Winchester and moved to Portsmouth, England in 1804. Chubb moved the company 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 joined the company, they sold Jeremiah's patented detector lock. In 1823, the company was awarded a special licence by George IV, became the sole supplier of locks to the General Post Office, a supplier to Her Majesty's Prison Service. In 1835, they received a patent for a burglar resisting safe, opened a safe factory in London in 1837. In 1851, they designed a special secure display case for the Koh-i-Noor diamond for its appearance at The Great Exhibition. In August 1984, the company was purchased by Racal under the chairmanship of Sir Ernest Harrison OBE.
After the group was floated out from Racal, in February 1997 it was bought by Williams plc. In August 2000, they were sold to Assa Abloy. In 2006, Chubb was merged into the group Mul-T-Lock within Assa Abloy; the Chubb Electronic Security subsidiaries produce smoke detectors, fire alarms, burglar alarms and glass break detectors. Sherlock Holmes says in the Arthur Conan Doyle short story "A Scandal in Bohemia" that Irene Adler has a Chubb lock on her London villa's door. Chubb Security Baron Hayter Glass break detector Yale Business Technology Association Westminster Group Security lighting Fire alarms Burglar alarms Official website Archive images from the Express & Star
Yale is a lock manufacturer owned by Assa Abloy. It is associated with the pin tumbler lock, known as the Yale lock; the business was founded as the Yale Lock Manufacturing Co. in Stamford, Connecticut, in 1868 by Linus Yale, Jr. the inventor of the pin tumbler lock, Henry R. Towne; the name was changed to Yale & Towne. Yale registered 8 patents with the U. S. Patent and Trademark Office between 1843 to 1857 about his pin tumbler safe lock, safe lock, bank lock and safe door bolt and padlock. In the twentieth century, the company expanded worldwide through purchases and joint ventures with other companies in the industry, employed more than 12,000 people, it established a British operation by acquiring the business of H&T Vaughan, a long established lock manufacturer in Wood Street, the historic centre of the British lock industry, became the major employer in the town. The British Yale became involved with the early motor industry and supplied locks to various manufacturers until the early thirties when the cheaper diecast based leaf tumbler technology became available.
Yale saw an unexpected revival of activity in the motor trade from the 1960s onwards when security fitters adopted its'M69' window lock as a simple add on fitting to prevent theft on vans. This continued to the early 1990s; the British Yale had continued to supply all lock requirements to Rolls-Royce Motors until 1991, when there was an acrimonious parting. The British business had been sold by its parent to the Valor Company in 1987. After a further takeover by Williams Holdings, various sections of the Willenhall operation and outlying operation such as their diecasting foundry were closed; this led to all work being outsourced to the Far East, the entire Wood Street site was closed soon thereafter and demolished, after having employed generations of skilled local people. The remainder of the British business was sold to Assa Abloy in March 2000; the Yale Security subsidiaries produce burglar alarms and glass break detectors. From July 2012, Assa Abloy started to relocate Yale from Lenoir City, Tennessee to Berlin, to completed by late spring of 2013, with the loss of about 200 jobs.
The factory had been in Lenoir City since 1953, at one time, had over 12000 workers. The ADT Corporation Business Technology Association Chubb Locks Chubb Electronic Security Security lighting Westminster Group www.yalelock.com — official site, United States www.yale.co.uk — official site, United Kingdom www.yale.co.in - Official Site, India
Fast Fourier transform
A fast Fourier transform is an algorithm that computes the discrete Fourier transform of a sequence, or its inverse. Fourier analysis converts a signal from its original domain 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 too slow to be practical. An FFT computes such transformations by factorizing the DFT matrix into a product of sparse factors; as a result, it manages to reduce the complexity of computing the DFT from O, which arises if one applies the definition of DFT, to O, where n is the data size. The difference in speed can be enormous for long data sets where N may be in the thousands or millions. In the presence of round-off error, many FFT algorithms are much more accurate than evaluating the DFT definition directly. There are many different FFT algorithms based on a wide range of published theories, from simple complex-number arithmetic to group theory and number theory.
Fast Fourier transforms are used for applications in engineering and mathematics. The basic ideas were popularized in 1965, but some algorithms had been derived as early as 1805. In 1994, Gilbert Strang described the FFT as "the most important numerical algorithm of our lifetime", it was included in Top 10 Algorithms of 20th Century by the IEEE journal Computing in Science & Engineering; the best-known FFT algorithms depend upon the factorization of N, but there are FFTs with O complexity for all N for prime N. Many FFT algorithms only depend on the fact that e − 2 π i / N is an N-th primitive root of unity, thus can be applied to analogous transforms over any finite field, such as number-theoretic transforms. Since the inverse DFT is the same as the DFT, but with the opposite sign in the exponent and a 1/N factor, any FFT algorithm can be adapted for it; the development of fast algorithms for DFT can be traced to Gauss's unpublished work in 1805 when he needed it to interpolate the orbit of asteroids Pallas and Juno from sample observations.
His method was similar to the one published in 1965 by Cooley and Tukey, who are credited for the invention of the modern generic FFT algorithm. While Gauss's work predated Fourier's results in 1822, he did not analyze the computation time and used other methods to achieve his goal. Between 1805 and 1965, some versions of FFT were published by other authors. Frank Yates in 1932 published his version called interaction algorithm, which provided efficient computation of Hadamard and Walsh transforms. Yates' algorithm is still used in the field of statistical analysis of experiments. In 1942, G. C. Danielson and Cornelius Lanczos published their version to compute DFT for x-ray crystallography, a field where calculation of Fourier transforms presented a formidable bottleneck. While many methods in the past had focused on reducing the constant factor for O computation by taking advantage of "symmetries", Danielson and Lanczos realized that one could use the "periodicity" and apply a "doubling trick" to get O runtime.
James Cooley and John Tukey published a more general version of FFT in 1965, applicable when N is composite and not a power of 2. Tukey came up with the idea during a meeting of President Kennedy's Science Advisory Committee where a discussion topic involved detecting nuclear tests by the Soviet Union by setting up sensors to surround the country from outside. To analyze the output of these sensors, a fast Fourier transform algorithm would be needed. In discussion with Tukey, Richard Garwin recognized the general applicability of the algorithm not just to national security problems, but to a wide range of problems including one of immediate interest to him, determining the periodicities of the spin orientations in a 3-D crystal of Helium-3. Garwin gave Tukey's idea to Cooley for implementation. Cooley and Tukey published the paper in a short time of six months; as Tukey did not work at IBM, the patentability of the idea was doubted and the algorithm went into the public domain, through the computing revolution of the next decade, made FFT one of the indispensable algorithms in digital signal processing.
Let x0.... XN−1 be complex numbers; the DFT is defined by the formula X k = ∑ n = 0 N − 1 x n e − i 2 π k n / N = ∑ n = 0 N − 1 x n w − k n k = 0, …, N − 1. Where w = e i 2 π / N
Discrete cosine transform
A discrete cosine transform expresses a finite sequence of data points in terms of a sum of cosine functions oscillating at different frequencies. DCTs are important to numerous applications in science and engineering, from lossy compression of audio and images, to spectral methods for the numerical solution of partial differential equations; the use of cosine rather than sine functions is critical for compression, since it turns out that fewer cosine functions are needed to approximate a typical signal, whereas for differential equations the cosines express a particular choice of boundary conditions. In particular, a DCT is a Fourier-related transform similar to the discrete Fourier transform, but using only real numbers; the DCTs are related to Fourier Series coefficients of a periodically and symmetrically extended sequence whereas DFTs are related to Fourier Series coefficients of a periodically extended sequence. DCTs are equivalent to DFTs of twice the length, operating on real data with symmetry, whereas in some variants the input and/or output data are shifted by half a sample.
There are eight standard DCT variants. The most common variant of discrete cosine transform is the type-II DCT, called "the DCT", its inverse, the type-III DCT, is correspondingly called "the inverse DCT" or "the IDCT". Two related transforms are the discrete sine transform, equivalent to a DFT of real and odd functions, the modified discrete cosine transform, based on a DCT of overlapping data. Multidimensional DCTs are developed to extend the concept of DCT on MD Signals. There are several algorithms to compute MD DCT. A new variety of fast algorithms are developed to reduce the computational complexity of implementing DCT; the DCT, in particular the DCT-II, is used in signal and image processing for lossy compression, because it has a strong "energy compaction" property: in typical applications, most of the signal information tends to be concentrated in a few low-frequency components of the DCT. For correlated Markov processes, the DCT can approach the compaction efficiency of the Karhunen-Loève transform.
As explained below, this stems from the boundary conditions implicit in the cosine functions. A related transform, the modified discrete cosine transform, or MDCT, is used in AAC, Vorbis, WMA, MP3 audio compression. DCTs are widely employed in solving partial differential equations by spectral methods, where the different variants of the DCT correspond to different even/odd boundary conditions at the two ends of the array. DCTs are closely related to Chebyshev polynomials, fast DCT algorithms are used in Chebyshev approximation of arbitrary functions by series of Chebyshev polynomials, for example in Clenshaw–Curtis quadrature; the DCT is used in JPEG image compression, MJPEG, MPEG, DV, Theora video compression. There, the two-dimensional DCT-II of N × N blocks are computed and the results are quantized and entropy coded. In this case, N is 8 and the DCT-II formula is applied to each row and column of the block; the result is an 8 × 8 transform coefficient array in which the element is the DC component and entries with increasing vertical and horizontal index values represent higher vertical and horizontal spatial frequencies.
Multidimensional DCTs have several applications 3-D DCT-II has several new applications like Hyperspectral Imaging coding systems, variable temporal length 3-D DCT coding, video coding algorithms, adaptive video coding and 3-D Compression. Due to enhancement in the hardware and introduction of several fast algorithms, the necessity of using M-D DCTs is increasing. DCT-IV has gained popularity for its applications in fast implementation of real-valued polyphase filtering banks, lapped orthogonal transform and cosine-modulated wavelet bases. Like any Fourier-related transform, discrete cosine transforms express a function or a signal in terms of a sum of sinusoids with different frequencies and amplitudes. Like the discrete Fourier transform, a DCT operates on a function at a finite number of discrete data points; the obvious distinction between a DCT and a DFT is that the former uses only cosine functions, while the latter uses both cosines and sines. However, this visible difference is a consequence of a deeper distinction: a DCT implies different boundary conditions from the DFT or other related transforms.
The Fourier-related transforms that operate on a function over a finite domain, such as the DFT or DCT or a Fourier series, can be thought of as implicitly defining an extension of that function outside the domain. That is, once you write a function f as a sum of sinusoids, you can evaluate that sum at any x for x where the original f was not specified; the DFT, like the Fourier series, implies a periodic extension of the original function. A DCT, like a cosine transform, implies an extension of the original function. However, because DCTs operate on finite, discrete sequences, two issues arise that
A security alarm is a system designed to detect intrusion – unauthorized entry – into a building or other area. Security alarms are used in residential, commercial and military properties for protection against burglary or property damage, as well as personal protection against intruders. Security alarms in residential areas show a correlation with decreased theft. Car alarms help protect vehicles and their contents. Prisons use security systems for control of inmates; some alarm systems serve a single purpose of burglary protection. Intrusion alarm systems may be combined with closed-circuit television surveillance systems to automatically record the activities of intruders, may interface to access control systems for electrically locked doors. Systems range from small, self-contained noisemakers, to complicated, multirally systems with computer monitoring and control, it may include two-way voice which allows communication between the panel and Monitoring station. The most basic alarm consists of one or more sensors to detect intruders, an alerting device to indicate the intrusion.
However, a typical premises security alarm employs the following components: Premises control unit, Alarm Control Panel, or panel: The "brain" of the system, it reads sensor inputs, tracks arm/disarm status, signals intrusions. In modern systems, this is one or more computer circuit boards inside a metal enclosure, along with a power supply. Sensors: Devices which detect intrusions. Sensors may be placed at the perimeter of the protected area, within it, or both. Sensors can detect intruders by a variety of methods, such as monitoring doors and windows for opening, or by monitoring unoccupied interiors for motions, vibration, or other disturbances. Alerting devices: These indicate an alarm condition. Most these are bells, and/or flashing lights. Alerting devices serve the dual purposes of warning occupants of intrusion, scaring off burglars; these devices may be used to warn occupants of a fire or smoke condition. Keypads: Small devices wall-mounted, which function as the human-machine interface to the system.
In addition to buttons, keypads feature indicator lights, a small multi-character display, or both.ect Interconnections between components. This may consist of wireless links with local power supplies. In addition to the system itself, security alarms are coupled with a monitoring service. In the event of an alarm, the premises control unit contacts a central monitoring station. Operators at the station see the signal and take appropriate action, such as contacting property owners, notifying police, or dispatching private security forces; such signals may be transmitted via telephone lines, or the internet. The hermetically sealed reed switch is a common type of two piece sensor that operates with an electrically conductive reed switch, either open or closed when under the influence of a magnetic field as in the case of proximity to the second piece which contains a magnet; when the magnet is moved away from the reed switch, the reed switch either closes or opens, again based on whether or not the design is open or closed.
This action coupled with an electric current allows an alarm control panel to detect a fault on that zone or circuit. These type of sensors are common and are found either wired directly to an alarm control panel, or they can be found in wireless door or window contacts as sub-components; the passive infrared motion detector is one of the most common sensors found in household and small business environments. It offers reliable functionality; the term passive refers to the fact that the detector does not radiate its own energy. Speaking, PIR sensors do not detect motion; as an intruder walks in front of the sensor, the temperature at that point will rise from room temperature to body temperature, back again. This quick change triggers the detection. PIR sensors may be designed to be wall- or ceiling-mounted, come in various fields of view, from narrow-point detectors to 360-degree fields. PIRs require a power supply in addition to the detection signalling circuit; the infrasound detector works by detecting sound waves at frequencies below 20 hertz.
Sounds at those frequencies are inaudible to the human ear. Due to its inherent properties, infrasound can travel distances of many hundreds of kilometers. Infrasound signals can result from volcanic eruptions, gravity waves and closing of doors, forcing windows to name a few; the entire infrasound detection system consists of the following components: a speaker as a microphone input, an order-frequency filter, an analog to digital converter, an MCU, used to analyse the recorded signal. Each time a potential intruder tries enter into a house, she or he tests whether it is closed and locked, uses tools on openings, or/and applies pressure, therefore he or she creates low-frequency sound vibrations; such actions are detected by the infrasound detector before the intruder breaks in. The primary purpose of such system is to stop burglars before they enter the house, to avoid not only theft, but vandalism; the sensitivity can be modulated depending on the size of a presence of animals. Using frequencies between 15 kHz and 75 kHz, these active detectors transmit ultras