Closed-circuit television known as video surveillance, is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not transmitted, though it may employ point to point, point to multipoint, or mesh wired or wireless links. Though all video cameras fit this definition, the term is most applied to those used for surveillance in areas that may need monitoring such as banks and other areas where security is needed. Though Videotelephony is called'CCTV' one exception is the use of video in distance education, where it is an important tool. Surveillance of the public using CCTV is common in many areas around the world. In recent years, the use of body worn video cameras has been introduced as a new form of surveillance used in law enforcement, with cameras located on a police officer's chest or head. Video surveillance has generated significant debate about balancing its use with individuals' right to privacy when in public.
In industrial plants, CCTV equipment may be used to observe parts of a process from a central control room, for example when the environment is not suitable for humans. CCTV systems may only as required to monitor a particular event. A more advanced form of CCTV, utilizing digital video recorders, provides recording for many years, with a variety of quality and performance options and extra features. More decentralized IP cameras equipped with megapixel sensors, support recording directly to network-attached storage devices, or internal flash for stand-alone operation. There are about 350 million surveillance cameras worldwide as of 2016. About 65% of these cameras are installed in Asia; the growth of CCTV has been slowing in recent years. The first CCTV system was installed by Siemens AG at Test Stand VII in Peenemünde, Nazi Germany in 1942, for observing the launch of V-2 rockets; the noted German engineer Walter Bruch was responsible for the technological design and installation of the system.
In the U. S. the first commercial closed-circuit television system became available in 1949, called Vericon. Little is known about Vericon except it was advertised as not requiring a government permit; the earliest video surveillance systems involved constant monitoring because there was no way to record and store information. The development of reel-to-reel media enabled the recording of surveillance footage; these systems required magnetic tapes to be changed manually, a time consuming and unreliable process, with the operator having to manually thread the tape from the tape reel through the recorder onto an empty take-up reel. Due to these shortcomings, video surveillance was not widespread. VCR technology became available in the 1970s, making it easier to record and erase information, the use of video surveillance became more common. During the 1990s, digital multiplexing was developed, allowing several cameras to record at once, as well as time lapse and motion-only recording; this increased savings of time and money which led to an increase in the use of CCTV.
CCTV technology has been enhanced with a shift toward Internet-based products and systems, other technological developments. Closed-circuit television was used as a form of pay-per-view theatre television for sports such as professional boxing and professional wrestling. Boxing telecasts were broadcast live to a select number of venues theaters, where viewers paid for tickets to watch the fight live; the first fight with a closed-circuit telecast was Joe Louis vs. Joe Walcott in 1948. Closed-circuit telecasts peaked in popularity with Muhammad Ali in the 1960s and 1970s, with "The Rumble in the Jungle" fight drawing 50 million CCTV viewers worldwide in 1974, the "Thrilla in Manila" drawing 100 million CCTV viewers worldwide in 1975. In 1985, the WrestleMania I professional wrestling show was seen by over one million viewers with this scheme; as late as 1996, the Julio César Chávez vs. Oscar De La Hoya boxing fight had 750,000 viewers. Closed-circuit television was replaced by pay-per-view home cable television in the 1980s and 1990s.
In September 1968, New York was the first city in the United States to install video cameras along its main business street in an effort to fight crime. Another early appearance was in 1973 in Times Square in New York City; the NYPD installed it in order to deter crime, occurring in the area. During the 1980s video surveillance began to spread across the country targeting public areas, it was seen as a cheaper way to deter crime compared to increasing the size of the police departments. Some businesses as well those that were prone to theft, began to use video surveillance. From the mid-1990s on, police departments across the country installed an increasing number of cameras in various public spaces including housing projects and public parks departments. CCTV became common in banks and stores to discourage theft, by recording evidence of criminal activity. In 1998, 3,000 CCTV systems were in use in New York City. A study by Nieto in 2008 found many businesses in the United States had invested in video surveillance technology to protect products and promote safe workplace and consumer environments.
A nationwide survey of a wide variety of companies found. In private sector CCTV surveillance technology is operated in a wide variety of establishments such as in industry/manufacturing, financial/insurance/banking and distribution, util
In architecture, a turret is a small tower that projects vertically from the wall of a building such as a medieval castle. Turrets were used to provide a projecting defensive position allowing covering fire to the adjacent wall in the days of military fortification; as their military use faded, turrets were used for decorative purposes, as in the Scottish baronial style. A turret can have a circular top with crenelations as seen in the picture at right, a pointed roof, or other kind of apex, it might contain a staircase. A building may have both turrets; the size of a turret is therefore limited, since it puts additional stresses on the structure of the building. Turrets were traditionally supported by a corbel. In modern times, a gun turret is a weapon mount that houses the crew or mechanism of a projectile-firing weapon, allowing the weapon to be aimed and fired in some degree of azimuth and elevation, it can be found on warships, combat vehicles, military aircraft, land fortifications, offers some degree of armour or protection.
Bartizan, an overhanging, wall-mounted turret found on French and Spanish fortifications between the early 14th and the 16th century. They returned to prominence in the 19th century with their popularity in Scottish baronial style. Bay window Oriel window
A merlon is the solid upright section of a battlement in medieval architecture or fortifications. Merlons are sometimes pierced by narrow, vertical embrasures or slits designed for observation and fire; the space between two merlons is called a crenel, a succession of merlons and crenels is a crenellation. Crenels designed in eras for use by cannons were called embrasures; the word comes from the French language, adapted from the Italian merlone a shortened form of mergola, connected with Latin mergae, or from a diminutive moerulus, from murus or moerus. An alternative etymology suggests that the medieval Latin merulus functioned as a diminutive of Latin merle, "blackbird", expressing an image of this bird sitting on a wall; as an essential part of battlements, merlons were used in fortifications for millennia. The best-known examples appear on medieval buildings, where battlements, though defensive, could be attractively formed, thus having a secondary decorative purpose; some buildings have false "decorative battlements".
The two most notable European variants in Middle Ages merlons shape were the Ghibelline and the Guelph merlon: the former ended in the upper part with a swallow-tailed form, while the latter term indicates the normal rectangular shape merlons. Other shapes include: three-pointed, shielded, flower-like, pyramidal, etc. depending either from the type of attacks expected or aesthetic considerations. In Roman times, the merlons had a width sufficient to shelter a single man; as new weapons appeared in the Middle Ages, the merlons were enlarged and provided with loop-holes of various dimensions and shapes, varying from rounded to cruciform. From the 13th century, the merlons could be used to pivot wooden shutters; the shutters could be opened by hand, or by using a pulley. After falling out of favour when the invention of the cannon forced fortifications to take a much lower profile, merlons re-emerged as decorative features in buildings constructed in the neo-Gothic style of the 19th century; the three peaks of today's Tre Cime di Lavaredo in the Italian Dolomites were known as the Drei Zinnen, German for the Three Merlons.
Battlement Embrasure called a crenel Defensive walls Machicolation Balestracci, D.. "I materiali da costruzione nel castello medievale". Archeologia Medievale: 227–242. Luisi, R.. Scudi di pietra, I castelli e l’arte della guerra tra Medioevo e Rinascimento. Bari. ISBN 88-420-5083-0
A parapet is a barrier, an extension of the wall at the edge of a roof, balcony, walkway or other structure. The word comes from the Italian parapetto; the German equivalent Brüstung has the same meaning. Where extending above a roof, a parapet may be the portion of an exterior wall that continues above the edge line of the roof surface, or may be a continuation of a vertical feature beneath the roof such as a fire wall or party wall. Parapets were used to defend buildings from military attack, but today they are used as guard rails and to prevent the spread of fires. Parapets may be plain, perforated or panelled, which are not mutually exclusive terms. Plain parapets are upward extensions of the wall, sometimes with a coping at the top and corbel below. Embattled parapets may be panelled, but are pierced, if not purely as stylistic device, for the discharge of defensive projectiles. Perforated parapets are pierced in various designs such as trefoils, or quatrefoils. Panelled parapets are ornamented by a series of panels, either oblong or square, more or less enriched, but not perforated.
These are common in the Perpendicular periods. The teachings of Moses prescribed parapets on roof edges for newly constructed houses as a safety measure; the Mirror Wall at Sigiriya, Sri Lanka built between 477 and 495 AD is one of the few surviving protective parapet walls from antiquity. Built onto the side of Sigiriya Rock it ran for a distance of 250 meters and provided protection from inclement weather. Only about one hundred meters of this wall exists today, but brick debris and grooves on the rock face along the western side of the rock show where the rest of this wall once stood. Parapets surrounding roofs are common in London; this dates from the Building Act of 1707 which banned projecting wooden eaves in the cities of Westminster and London as a fire risk. Instead an 18-inch brick parapet was required, with the roof set behind; this was continued in many Georgian houses, as it gave the appearance of a flat roof which accorded with the desire for classical proportions. Many firewalls are required to have a portion of the wall extending above the roof.
The parapet is required to be as fire resistant as the lower wall, extend a distance prescribed by building code. Parapets on bridges and other highway structures prevent users from falling off where there is a drop, they may be meant to restrict views, to prevent rubbish passing below, to act as noise barriers. Bridge parapets may be made from any material, but structural steel, aluminium and reinforced concrete are common, they may be of framed construction. In European standards, parapets are defined as a sub-category of "vehicle restraint systems" or "pedestrian restraint systems". In terms of fortification, a parapet is a wall of stone, wood or earth on the outer edge of a defensive wall or trench, which shelters the defenders. In medieval castles, they were crenellated. In artillery forts, parapets tend to be higher and thicker, they could be provided with embrasures for the fort's guns to fire through, a banquette or fire-step so that defending infantry could shoot over the top. The top of the parapet slopes towards the enemy to enable the defenders to shoot downwards.
In śilpaśāstra, the ancient Indian science of sculpture, a parapet is known as hāra. It is optionally added while constructing a temple; the hāra can be decorated according to the Kāmikāgama. Attic style Breastwork Merlon Redoubt Senani Ponnamperuma; the Story of Sigiriya, Panique Pty Ltd, 2013 pp 124–127, 179. ISBN 978-0987345141. Victorian Forts glossary Parapet What is a Parapet
Assyria called the Assyrian Empire, was a Mesopotamian kingdom and empire of the ancient Near East and the Levant. It existed as a state from as early as the 25th century BC until its collapse between 612 BC and 609 BC - spanning the periods of the Early to Middle Bronze Age through to the late Iron Age. From the end of the seventh century BC to the mid-seventh century AD, it survived as a geopolitical entity, for the most part ruled by foreign powers such as the Parthian and early Sasanian Empires between the mid-second century BC and late third century AD, the final part of which period saw Mesopotamia become a major centre of Syriac Christianity and the birthplace of the Church of the East. A Semitic-speaking realm, Assyria was centred on the Tigris in Upper Mesopotamia; the Assyrians came to rule powerful empires in several periods. Making up a substantial part of the greater Mesopotamian "cradle of civilization", which included Sumer, the Akkadian Empire, Babylonia, Assyria reached the height of technological and cultural achievements for its time.
At its peak, the Neo-Assyrian Empire of 911 to 609 BC stretched from Cyprus and the East Mediterranean to Iran, from present-day Armenia and Azerbaijan in the Caucasus to the Arabian Peninsula and eastern Libya. The name "Assyria" originates with the Assyrian state's original capital, the ancient city of Aššur, which dates to c. 2600 BC - one of a number of Akkadian-speaking city-states in Mesopotamia. In the 25th and 24th centuries BC, Assyrian kings were pastoral leaders. From the late 24th century BC, the Assyrians became subject to Sargon of Akkad, who united all the Akkadian- and Sumerian-speaking peoples of Mesopotamia under the Akkadian Empire, which lasted from c. 2334 BC to 2154 BC. After the Assyrian Empire fell from power, the greater remaining part of Assyria formed a geopolitical region and province of other empires, although between the mid-2nd century BC and late 3rd century AD a patchwork of small independent Assyrian kingdoms arose in the form of Assur, Osroene, Beth Nuhadra, Beth Garmai and Hatra.
The region of Assyria fell under the successive control of the Median Empire of 678 to 549 BC, the Achaemenid Empire of 550 to 330 BC, the Macedonian Empire, the Seleucid Empire of 312 to 63 BC, the Parthian Empire of 247 BC to 224 AD, the Roman Empire and the Sasanian Empire of 224 to 651 AD. The Arab Islamic conquest of the area in the mid-seventh century dissolved Assyria as a single entity, after which the remnants of the Assyrian people became an ethnic, linguistic and religious minority in the Assyrian homeland, surviving there to this day as an indigenous people of the region. Assyria was sometimes known as Subartu and Azuhinum prior to the rise of the city-state of Ashur, after which it was Aššūrāyu, after its fall, from 605 BC through to the late seventh century AD variously as Achaemenid Assyria, referenced as Atouria, Ator and sometimes as Syria which etymologically derives from Assyria according to Strabo, Assyria and Asōristān. "Assyria" can refer to the geographic region or heartland where Assyria, its empires and the Assyrian people were centered.
The indigenous modern Eastern Aramaic-speaking Assyrian Christian ethnic minority in northern Iraq, north east Syria, southeast Turkey and northwest Iran are the descendants of the ancient Assyrians. As Babylonia is called after the city of Babylon, Assyria means "land of Asshur"Etymologically, Assyria is connected to the name of Syria, with both being derived from the Akkadian Aššur. Theodor Nöldeke in 1881 was the first to give philological support to the assumption that Syria and Assyria have the same etymology, a suggestion going back to John Selden. A 21st-century discovery of the Çineköy inscription confirmed that Syria, being a Greek corruption of the name Assyria, is derived from the Assyrian term Aššūrāyu. In prehistoric times, the region, to become known as Assyria was home to a Neanderthal culture such as has been found at the Shanidar Cave; the earliest Neolithic sites in what will be Assyria were the Jarmo culture c. 7100 BC, the Halaf culture c. 6100 BC, the Hassuna culture c. 6000 BC.
The Akkadian-speaking people who would found Assyria appear to have entered Mesopotamia at some point during the latter 4th millennium BC intermingling with the earlier Sumerian-speaking population, who came from northern Mesopotamia, with Akkadian names appearing in written record from as early as the 29th century BC. During the 3rd millennium BC, a intimate cultural symbiosis developed between the Sumerians and the Akkadians throughout Mesopotamia, which included widespread bilingualism; the influence of Sumerian on Akkadian, vice versa, is evident in all areas, from lexical borrowing on a massive scale, to syntactic and phonological convergence. This has prompted scholars to refer to Sumerian and Akkadian in the third millennium BC as a sprachbund. Akkadian replaced Sumerian as the spoken language of Mesopotamia somewhere after the turn of the 3rd and the 2nd millennium BC, although Sumerian continued to be used as a sacred, ceremonial and scientific language in Mesopotamia until the 1st century AD, as did use of the Akkadian cuneiform.
The cities of A
Great Wall of China
The Great Wall of China is a series of fortifications made of stone, tamped earth and other materials built along an east-to-west line across the historical northern borders of China to protect the Chinese states and empires against the raids and invasions of the various nomadic groups of the Eurasian Steppe with an eye to expansion. Several walls were being built from as early as the 7th century BC. Little of that wall remains. On, many successive dynasties have repaired and newly built multiple stretches of border walls; the most well-known of the walls were built during the Ming dynasty. Apart from defense, other purposes of the Great Wall have included border controls, allowing the imposition of duties on goods transported along the Silk Road, regulation or encouragement of trade and the control of immigration and emigration. Furthermore, the defensive characteristics of the Great Wall were enhanced by the construction of watch towers, troop barracks, garrison stations, signaling capabilities through the means of smoke or fire, the fact that the path of the Great Wall served as a transportation corridor.
The frontier walls built by different dynasties have multiple courses. Collectively, they stretch from Dandong in the east to Lop Lake in the west, from present-day Sino-Russian border in the north to Qinghai in the south. A comprehensive archaeological survey, using advanced technologies, has concluded that the walls built by the Ming dynasty measure 8,850 km; this is made up of 6,259 km sections of actual wall, 359 km of trenches and 2,232 km of natural defensive barriers such as hills and rivers. Another archaeological survey found that the entire wall with all of its branches measures out to be 21,196 km. Today, the Great Wall is recognized as one of the most impressive architectural feats in history; the collection of fortifications known as the Great Wall of China has had a number of different names in both Chinese and English. In Chinese histories, the term "Long Rampart" appears in Sima Qian's Records of the Grand Historian, where it referred both to the separate great walls built between and north of the Warring States and to the more unified construction of the First Emperor.
The Chinese character 城, meaning city or fortress, is a phono-semantic compound of the "earth" radical 土 and phonetic 成, whose Old Chinese pronunciation has been reconstructed as *deŋ. It referred to the rampart which surrounded traditional Chinese cities and was used by extension for these walls around their respective states; the longer Chinese name "Ten-Thousand Mile Long Wall" came from Sima Qian's description of it in the Records, though he did not name the walls as such. The AD 493 Book of Song quotes the frontier general Tan Daoji referring to "the long wall of 10,000 miles", closer to the modern name, but the name features in pre-modern times otherwise; the traditional Chinese mile was an irregular distance, intended to show the length of a standard village and varied with terrain but was standardized at distances around a third of an English mile. Since China's metrication in 1930, it has been equivalent to 500 metres or 1,600 feet, which would make the wall's name describe a distance of 5,000 km.
However, this use of "ten-thousand" is figurative in a similar manner to the Greek and English myriad and means "innumerable" or "immeasurable". Because of the wall's association with the First Emperor's supposed tyranny, the Chinese dynasties after Qin avoided referring to their own additions to the wall by the name "Long Wall". Instead, various terms were used in medieval records, including "frontier", "rampart", "barrier", "the outer fortresses", "the border wall". Poetic and informal names for the wall included "the Purple Frontier" and "the Earth Dragon". Only during the Qing period did "Long Wall" become the catch-all term to refer to the many border walls regardless of their location or dynastic origin, equivalent to the English "Great Wall"; the current English name evolved from accounts of "the Chinese wall" from early modern European travelers. By the 19th century, "The Great Wall of China" had become standard in English and French, although other European languages such as German continue to refer to it as "the Chinese wall."
The Chinese were familiar with the techniques of wall-building by the time of the Spring and Autumn period between the 8th and 5th centuries BC. During this time and the subsequent Warring States period, the states of Qin, Zhao, Qi, Zhongshan all constructed extensive fortifications to defend their own borders. Built to withstand the attack of small arms such as swords and spears, these walls were made by stamping earth and gravel between board frames. King Zheng of Qin conquered the last of his opponents and unified China as the First Emperor of the Qin dynasty in 221 BC. Intending to impose centralized rule and prevent the resurgence of feudal lords, he ordered the destruction of the sections of the walls that divided his empire among the former states. To position the empire against the Xiongnu people from the north, however, he ordered the building of new walls to connect the remaining fortifications along the empire's northern frontier. "Build and move on" was a central guiding principle in
Persepolis was the ceremonial capital of the Achaemenid Empire. It is situated 60 km northeast of the city of Shiraz in Iran; the earliest remains of Persepolis date back to 515 BCE. It exemplifies the Achaemenid style of architecture. UNESCO declared the ruins of Persepolis a World Heritage Site in 1979; the English word Persepolis is derived from Greek Persépolis, a compound of Pérsēs and pólis, meaning "the Persian city" or "the city of the Persians". To the ancient Persians, the city was known as Pārsa, the word for the region of Persia. An inscription left by Sasanian prince Shapur Sakanshah, the son of Hormizd II, refers to the site as Sad-stūn, meaning "Hundred Pillars"; because medieval Persians attributed the site to Jamshid, an Iranian mythological king, it has been referred to as Takht-e-Jamshid meaning "Throne of Jamshid". Another name given to the site in the medieval period was Čehel Menār meaning "Forty Minarets". Persepolis is near the small river Pulvar; the site includes a 125,000 square meter terrace artificially constructed and cut out of a mountain, with its east side leaning on Rahmat Mountain.
The other three sides are formed by retaining walls, which vary in height with the slope of the ground. Rising from 5–13 metres on the west side was a double stair. From there, it slopes to the top. To create the level terrace, depressions were filled with soil and heavy rocks, which were joined together with metal clips. Archaeological evidence shows that the earliest remains of Persepolis date back to 515 BC. André Godard, the French archaeologist who excavated Persepolis in the early 1930s, believed that it was Cyrus the Great who chose the site of Persepolis, but that it was Darius I who built the terrace and the palaces. Inscriptions on these buildings support the belief. With Darius I, the scepter passed to a new branch of the royal house. Persepolis became the capital of Persia proper during his reign. However, the city's location in a remote and mountainous region made it an inconvenient residence for the rulers of the empire; the country's true capitals were Susa and Ecbatana. This may be why the Greeks were not acquainted with the city until Alexander the Great took and plundered it.
Darius I's construction of Persepolis were carried out parallel to those of the Palace of Susa. According to Gene R. Garthwaite, the Susa Palace served as Darius' model for Persepolis. Darius I ordered the construction of the Apadana and the Council Hall, as well as the main imperial Treasury and its surroundings; these were completed during the reign of his son, Xerxes I. Further construction of the buildings on the terrace continued until the downfall of the Achaemenid Empire. According to the Encyclopædia Britannica, the Greek historian Ctesias mentioned that Darius I's grave was in a cliff face that could be reached with an apparatus of ropes. Around 519 BC, construction of a broad stairway was begun; the stairway was planned to be the main entrance to the terrace 20 metres above the ground. The dual stairway, known as the Persepolitan Stairway, was built symmetrically on the western side of the Great Wall; the 111 steps measured 6.9 metres wide, with treads of 31 centimetres and rises of 10 centimetres.
The steps were believed to have been constructed to allow for nobles and royalty to ascend by horseback. New theories, suggest that the shallow risers allowed visiting dignitaries to maintain a regal appearance while ascending; the top of the stairways led to a small yard in the north-eastern side of the terrace, opposite the Gate of All Nations. Grey limestone was the main building material used at Persepolis. After natural rock had been leveled and the depressions filled in, the terrace was prepared. Major tunnels for sewage were dug underground through the rock. A large elevated water storage tank was carved at the eastern foot of the mountain. Professor Olmstead suggested the cistern was constructed at the same time that construction of the towers began; the uneven plan of the terrace, including the foundation, acted like a castle, whose angled walls enabled its defenders to target any section of the external front. Diodorus Siculus writes that Persepolis had three walls with ramparts, which all had towers to provide a protected space for the defense personnel.
The first wall was 7 metres tall, the second, 14 metres and the third wall, which covered all four sides, was 27 metres in height, though no presence of the wall exists in modern times. The function of Persepolis remains rather unclear, it was not one of the largest cities in Persia, let alone the rest of the empire, but appears to have been a grand ceremonial complex, only occupied seasonally. Until recent challenges, most archaeologists held that it was used for celebrating Nowruz, the Persian New Year, held at the spring equinox, still an important annual festivity in modern Iran; the Iranian nobility and the tributary parts of the empire came to present gifts to the king, as represented in the stairway reliefs. After invading Achaemenid Persia in 330 BC, Alexander the Great sent the main force of his army to Persepolis by the Royal Road, he stormed a pass through modern-day Zagros Mountains. There Ariobarzanes of Persis ambushed Alexander the Great's army, inflicting heavy casualties. After being held off for 30 days, Alexander t