St. Louis is an independent city and major inland port in the U. S. state of Missouri. It is situated along the western bank of the Mississippi River, which marks Missouri's border with Illinois; the Missouri River merges with the Mississippi River just north of the city. These two rivers combined form the fourth longest river system in the world; the city had an estimated 2017 population of 308,626 and is the cultural and economic center of the St. Louis metropolitan area, the largest metropolitan area in Missouri, the second-largest in Illinois, the 22nd-largest in the United States. Before European settlement, the area was a regional center of Native American Mississippian culture; the city of St. Louis was founded in 1764 by French fur traders Pierre Laclède and Auguste Chouteau, named after Louis IX of France. In 1764, following France's defeat in the Seven Years' War, the area was ceded to Spain and retroceded back to France in 1800. In 1803, the United States acquired the territory as part of the Louisiana Purchase.
During the 19th century, St. Louis became a major port on the Mississippi River, it separated from St. Louis County in 1877, becoming an independent city and limiting its own political boundaries. In 1904, it hosted the Summer Olympics; the economy of metropolitan St. Louis relies on service, trade, transportation of goods, tourism, its metro area is home to major corporations, including Anheuser-Busch, Express Scripts, Boeing Defense, Energizer, Enterprise, Peabody Energy, Post Holdings, Edward Jones, Go Jet and Sigma-Aldrich. Nine of the ten Fortune 500 companies based in Missouri are located within the St. Louis metropolitan area; this city has become known for its growing medical and research presence due to institutions such as Washington University in St. Louis and Barnes-Jewish Hospital. St. Louis has two professional sports teams: the St. Louis Cardinals of Major League Baseball and the St. Louis Blues of the National Hockey League. One of the city's iconic sights is the 630-foot tall Gateway Arch in the downtown area.
The area that would become St. Louis was a center of the Native American Mississippian culture, which built numerous temple and residential earthwork mounds on both sides of the Mississippi River, their major regional center was at Cahokia Mounds, active from 900 to 1500. Due to numerous major earthworks within St. Louis boundaries, the city was nicknamed as the "Mound City"; these mounds were demolished during the city's development. Historic Native American tribes in the area included the Siouan-speaking Osage people, whose territory extended west, the Illiniwek. European exploration of the area was first recorded in 1673, when French explorers Louis Jolliet and Jacques Marquette traveled through the Mississippi River valley. Five years La Salle claimed the region for France as part of La Louisiane; the earliest European settlements in the area were built in Illinois Country on the east side of the Mississippi River during the 1690s and early 1700s at Cahokia and Fort de Chartres. Migrants from the French villages on the opposite side of the Mississippi River founded Ste.
Genevieve in the 1730s. In early 1764, after France lost the 7 Years' War, Pierre Laclède and his stepson Auguste Chouteau founded what was to become the city of St. Louis; the early French families built the city's economy on the fur trade with the Osage, as well as with more distant tribes along the Missouri River. The Chouteau brothers gained a monopoly from Spain on the fur trade with Santa Fe. French colonists used African slaves as domestic workers in the city. France, alarmed that Britain would demand French possessions west of the Mississippi and the Missouri River basin after the losing New France to them in 1759–60, transferred these to Spain as part of the Viceroyalty of New Spain; these areas remained in Spanish possession until 1803. In 1780 during the American Revolutionary War, St. Louis was attacked by British forces Native American allies, in the Battle of St. Louis; the founding of St. Louis began in 1763. Pierre Laclede led an expedition to set up a fur-trading post farther up the Mississippi River.
Before Laclede had been a successful merchant. For this reason, he and his trading partner Gilbert Antoine de St. Maxent were offered monopolies for six years of the fur trading in that area. Although they were only granted rights to set-up a trading post and other members of his expedition set up a settlement; some historians believe that Laclede's determination to create this settlement was the result of his affair with a married woman Marie-Thérèse Bourgeois Chouteau in New Orleans. Laclede on his initial expedition was accompanied by Auguste Chouteau; some historians still debate. The reason for this lingering question is that all the documentation of the founding was loaned and subsequently destroyed in a fire. For the first few years of St. Louis's existence, the city was not recognized by any of the governments. Although thought to be under the control of the Spanish government, no one asserted any authority over the settlement, thus St. Louis had no local government; this led Laclede to assume a position of civil control, all problems were disposed i
Computer science is the study of processes that interact with data and that can be represented as data in the form of programs. It enables the use of algorithms to manipulate and communicate digital information. A computer scientist studies the theory of computation and the practice of designing software systems, its fields can be divided into practical disciplines. Computational complexity theory is abstract, while computer graphics emphasizes real-world applications. Programming language theory considers approaches to the description of computational processes, while computer programming itself involves the use of programming languages and complex systems. Human–computer interaction considers the challenges in making computers useful and accessible; the earliest foundations of what would become computer science predate the invention of the modern digital computer. Machines for calculating fixed numerical tasks such as the abacus have existed since antiquity, aiding in computations such as multiplication and division.
Algorithms for performing computations have existed since antiquity before the development of sophisticated computing equipment. Wilhelm Schickard designed and constructed the first working mechanical calculator in 1623. In 1673, Gottfried Leibniz demonstrated a digital mechanical calculator, called the Stepped Reckoner, he may be considered the first computer scientist and information theorist, among other reasons, documenting the binary number system. In 1820, Thomas de Colmar launched the mechanical calculator industry when he released his simplified arithmometer, the first calculating machine strong enough and reliable enough to be used daily in an office environment. Charles Babbage started the design of the first automatic mechanical calculator, his Difference Engine, in 1822, which gave him the idea of the first programmable mechanical calculator, his Analytical Engine, he started developing this machine in 1834, "in less than two years, he had sketched out many of the salient features of the modern computer".
"A crucial step was the adoption of a punched card system derived from the Jacquard loom" making it infinitely programmable. In 1843, during the translation of a French article on the Analytical Engine, Ada Lovelace wrote, in one of the many notes she included, an algorithm to compute the Bernoulli numbers, considered to be the first computer program. Around 1885, Herman Hollerith invented the tabulator, which used punched cards to process statistical information. In 1937, one hundred years after Babbage's impossible dream, Howard Aiken convinced IBM, making all kinds of punched card equipment and was in the calculator business to develop his giant programmable calculator, the ASCC/Harvard Mark I, based on Babbage's Analytical Engine, which itself used cards and a central computing unit; when the machine was finished, some hailed it as "Babbage's dream come true". During the 1940s, as new and more powerful computing machines were developed, the term computer came to refer to the machines rather than their human predecessors.
As it became clear that computers could be used for more than just mathematical calculations, the field of computer science broadened to study computation in general. In 1945, IBM founded the Watson Scientific Computing Laboratory at Columbia University in New York City; the renovated fraternity house on Manhattan's West Side was IBM's first laboratory devoted to pure science. The lab is the forerunner of IBM's Research Division, which today operates research facilities around the world; the close relationship between IBM and the university was instrumental in the emergence of a new scientific discipline, with Columbia offering one of the first academic-credit courses in computer science in 1946. Computer science began to be established as a distinct academic discipline in the 1950s and early 1960s; the world's first computer science degree program, the Cambridge Diploma in Computer Science, began at the University of Cambridge Computer Laboratory in 1953. The first computer science degree program in the United States was formed at Purdue University in 1962.
Since practical computers became available, many applications of computing have become distinct areas of study in their own rights. Although many believed it was impossible that computers themselves could be a scientific field of study, in the late fifties it became accepted among the greater academic population, it is the now well-known IBM brand that formed part of the computer science revolution during this time. IBM released the IBM 704 and the IBM 709 computers, which were used during the exploration period of such devices. "Still, working with the IBM was frustrating if you had misplaced as much as one letter in one instruction, the program would crash, you would have to start the whole process over again". During the late 1950s, the computer science discipline was much in its developmental stages, such issues were commonplace. Time has seen significant improvements in the effectiveness of computing technology. Modern society has seen a significant shift in the users of computer technology, from usage only by experts and professionals, to a near-ubiquitous user base.
Computers were quite costly, some degree of humanitarian aid was needed for efficient use—in part from professional computer operators. As computer adoption became more widespread and affordable, less human assistance was needed for common usage. Despite its short history as a formal academic discipline, computer science has made a number of fundamental contributions to science and society—in fact, along with electronics, it is
A computer hacker is any skilled computer expert that uses their technical knowledge to overcome a problem. While "hacker" can refer to any skilled computer programmer, the term has become associated in popular culture with a "security hacker", someone who, with their technical knowledge, uses bugs or exploits to break into computer systems. Reflecting the two types of hackers, there are two definitions of the word "hacker": an adherent of the technology and programming subculture. Someone, able to subvert computer security. If doing so for malicious purposes, the person can be called a cracker. Today, mainstream usage of "hacker" refers to computer criminals, due to the mass media usage of the word since the 1980s; this includes what hacker slang calls "script kiddies", people breaking into computers using programs written by others, with little knowledge about the way they work. This usage has become so predominant that the general public is unaware that different meanings exist. While the self-designation of hobbyists as hackers is acknowledged and accepted by computer security hackers, people from the programming subculture consider the computer intrusion related usage incorrect, emphasize the difference between the two by calling security breakers "crackers".
The controversy is based on the assertion that the term meant someone messing about with something in a positive sense, that is, using playful cleverness to achieve a goal. But it is supposed, the meaning of the term shifted over the decades and came to refer to computer criminals; as the security-related usage has spread more the original meaning has become less known. In popular usage and in the media, "computer intruders" or "computer criminals" is the exclusive meaning of the word today. In the computer enthusiast community, the primary meaning is a complimentary description for a brilliant programmer or technical expert. A large segment of the technical community insist; the mainstream media's current usage of the term may be traced back to the early 1980s. When the term was introduced to wider society by the mainstream media in 1983 those in the computer community referred to computer intrusion as "hacking", although not as the exclusive definition of the word. In reaction to the increasing media use of the term with the criminal connotation, the computer community began to differentiate their terminology.
Alternative terms such as "cracker" were coined in an effort to maintain the distinction between "hackers" within the legitimate programmer community and those performing computer break-ins. Further terms such as "black hat", "white hat" and "gray hat" developed when laws against breaking into computers came into effect, to distinguish criminal activities from those activities which were legal. However, network news use of the term pertained to the criminal activities, despite the attempt by the technical community to preserve and distinguish the original meaning, so today the mainstream media and general public continue to describe computer criminals, with all levels of technical sophistication, as "hackers" and do not make use of the word in any of its non-criminal connotations. Members of the media sometimes seem unaware of the distinction, grouping legitimate "hackers" such as Linus Torvalds and Steve Wozniak along with criminal "crackers"; as a result, the definition is still the subject of heated controversy.
The wider dominance of the pejorative connotation is resented by many who object to the term being taken from their cultural jargon and used negatively, including those who have preferred to self-identify as hackers. Many advocate using the more recent and nuanced alternate terms when describing criminals and others who negatively take advantage of security flaws in software and hardware. Others prefer to follow common popular usage, arguing that the positive form is confusing and unlikely to become widespread in the general public. A minority still use the term in both senses despite the controversy, leaving context to clarify which meaning is intended. However, because the positive definition of hacker was used as the predominant form for many years before the negative definition was popularized, "hacker" can therefore be seen as a shibboleth, identifying those who use the technically-oriented sense as members of the computing community. On the other hand, due to the variety of industries software designers may find themselves in, many prefer not to be referred to as hackers because the word holds a negative denotation in many of those industries.
A possible middle ground position has been suggested, based on the observation that "hacking" describes a collection of skills and tools which are used by hackers of both descriptions for differing reasons. The analogy is made to locksmithing picking locks, a skill which can be used for good or evil; the primary weakness of this analogy is the inclusion of script kiddies in the popular usage of "hacker," despite their lack of an underlying skill and knowledge base. Sometimes, "hacker" is used synonymously with "geek": "A true hacker is not a group person. He's a person who loves to stay up all night, he and the machine in a love-hate relationship... They're kids who tended to be brilliant but not interested in conventional goals It's a term of derision and al
University of Arizona
The University of Arizona is a public research university in Tucson, Arizona. Founded in 1885, the UA was the first university in the Arizona Territory; as of 2017, the university enrolls 44,831 students in 19 separate colleges/schools, including the University of Arizona College of Medicine in Tucson and Phoenix and the James E. Rogers College of Law, is affiliated with two academic medical centers; the University of Arizona is governed by the Arizona Board of Regents. The University of Arizona is one of the elected members of the Association of American Universities and is the only representative from the state of Arizona to this group. Known as the Arizona Wildcats, the UA's intercollegiate athletic teams are members of the Pac-12 Conference of the NCAA. UA athletes have won national titles in several sports, most notably men's basketball and softball; the official colors of the university and its athletic teams are navy blue. After the passage of the Morrill Land-Grant Act of 1862, the push for a university in Arizona grew.
The Arizona Territory's "Thieving Thirteenth" Legislature approved the University of Arizona in 1885 and selected the city of Tucson to receive the appropriation to build the university. Tucson hoped to receive the appropriation for the territory's mental hospital, which carried a $100,000 allocation instead of the $25,000 allotted to the territory's only university. Flooding on the Salt River delayed Tucson's legislators, by they time they reached Prescott, back-room deals allocating the most desirable territorial institutions had been made. Tucson was disappointed with receiving what was viewed as an inferior prize. With no parties willing to provide land for the new institution, the citizens of Tucson prepared to return the money to the Territorial Legislature until two gamblers and a saloon keeper decided to donate the land to build the school. Construction of Old Main, the first building on campus, began on October 27, 1887, classes met for the first time in 1891 with 32 students in Old Main, still in use today.
Because there were no high schools in Arizona Territory, the university maintained separate preparatory classes for the first 23 years of operation. The University of Arizona offers bachelor's, master's, professional degrees. Grades are given on a strict 4-point scale with "A" worth 4, "B" worth 3, "C" worth 2, "D" worth 1 and "E" worth zero points; the Center for World University Rankings in 2017 ranked Arizona No. 52 in the world and 34 in the U. S; the 2018 Times Higher Education World University Rankings rated University of Arizona 161st in the world and the 2017/18 QS World University Rankings ranked it 230th. The University of Arizona was ranked tied for 77th in the "National Universities" category by U. S. News & World Report for 2018; the James E. Rogers College of Law Graduate School was ranked tied for 41st nationally; the College of Medicine was rated No. 7 among the nation's medical schools for Hispanic students, according to Hispanic Business Magazine. In 2017, the Eller MBA program was ranked 24th among public institutions and 49th nationally by U.
S. News & World Report, which placed the school's Management Information Systems program as 2nd, the Entrepreneurship program as 5th and the Part-time MBA 30th among U. S public schools. U. S. News & World Report rated UA as tied for 33rd for online MBA programs, tied for 49th for best online graduate nursing programs, tied for 33rd for best online graduate engineering programs nationally. UA graduate programs ranked in the top 25 in the nation by U. S. News & World Report for 2017 include Information Science, Geology and Seismology, Speech Pathology, Rehabilitation Counseling, Earth Sciences, Analytical Chemistry, Atomic/Molecular/Optical Sciences and Photography; the Council for Aid to Education ranked UA 12th among public universities and 24th overall in financial support and gifts. Campaign Arizona, an effort to raise over $1 billion for the school, exceeded that goal by $200 million a year earlier than projected. In April 2014, the "Arizona Now" campaign launched with a target of $1.5 billion.
As of 31 December 2016, the campaign has raised $1.59 Billion, two years ahead of schedule. In 2015, Design Intelligence ranked the College of Architecture and Landscape Architecture's undergraduate program in architecture 10th in the nation for all universities and private; the same publication ranked. The School of Middle Eastern and North African Studies at the University of Arizona is one of the most ranked area studies programs focusing on the Middle East in the United States. In addition to offering language training in Arabic, Hebrew and Turkish, it is collocated with the Middle East Studies Association; the School of Geography and Development is ranked as one of the top geography graduate programs in the US. The UA is considered a "selective" university by U. S. News & World Report. In the 2014-2015 academic year, 68 freshman students were National Merit Scholars. UA students hail from all states in the U. S. While nearly 69% of students are from Arizona, nearly 11% are from California, 8% are international, followed by a significant student presence from Texas, Washington and New York..
Tuition at the University o
International Standard Serial Number
An International Standard Serial Number is an eight-digit serial number used to uniquely identify a serial publication, such as a magazine. The ISSN is helpful in distinguishing between serials with the same title. ISSN are used in ordering, interlibrary loans, other practices in connection with serial literature; the ISSN system was first drafted as an International Organization for Standardization international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard; when a serial with the same content is published in more than one media type, a different ISSN is assigned to each media type. For example, many serials are published both in electronic media; the ISSN system refers to these types as electronic ISSN, respectively. Conversely, as defined in ISO 3297:2007, every serial in the ISSN system is assigned a linking ISSN the same as the ISSN assigned to the serial in its first published medium, which links together all ISSNs assigned to the serial in every medium.
The format of the ISSN is an eight digit code, divided by a hyphen into two four-digit numbers. As an integer number, it can be represented by the first seven digits; the last code digit, which may be 0-9 or an X, is a check digit. Formally, the general form of the ISSN code can be expressed as follows: NNNN-NNNC where N is in the set, a digit character, C is in; the ISSN of the journal Hearing Research, for example, is 0378-5955, where the final 5 is the check digit, C=5. To calculate the check digit, the following algorithm may be used: Calculate the sum of the first seven digits of the ISSN multiplied by its position in the number, counting from the right—that is, 8, 7, 6, 5, 4, 3, 2, respectively: 0 ⋅ 8 + 3 ⋅ 7 + 7 ⋅ 6 + 8 ⋅ 5 + 5 ⋅ 4 + 9 ⋅ 3 + 5 ⋅ 2 = 0 + 21 + 42 + 40 + 20 + 27 + 10 = 160 The modulus 11 of this sum is calculated. For calculations, an upper case X in the check digit position indicates a check digit of 10. To confirm the check digit, calculate the sum of all eight digits of the ISSN multiplied by its position in the number, counting from the right.
The modulus 11 of the sum must be 0. There is an online ISSN checker. ISSN codes are assigned by a network of ISSN National Centres located at national libraries and coordinated by the ISSN International Centre based in Paris; the International Centre is an intergovernmental organization created in 1974 through an agreement between UNESCO and the French government. The International Centre maintains a database of all ISSNs assigned worldwide, the ISDS Register otherwise known as the ISSN Register. At the end of 2016, the ISSN Register contained records for 1,943,572 items. ISSN and ISBN codes are similar in concept. An ISBN might be assigned for particular issues of a serial, in addition to the ISSN code for the serial as a whole. An ISSN, unlike the ISBN code, is an anonymous identifier associated with a serial title, containing no information as to the publisher or its location. For this reason a new ISSN is assigned to a serial each time it undergoes a major title change. Since the ISSN applies to an entire serial a new identifier, the Serial Item and Contribution Identifier, was built on top of it to allow references to specific volumes, articles, or other identifiable components.
Separate ISSNs are needed for serials in different media. Thus, the print and electronic media versions of a serial need separate ISSNs. A CD-ROM version and a web version of a serial require different ISSNs since two different media are involved. However, the same ISSN can be used for different file formats of the same online serial; this "media-oriented identification" of serials made sense in the 1970s. In the 1990s and onward, with personal computers, better screens, the Web, it makes sense to consider only content, independent of media; this "content-oriented identification" of serials was a repressed demand during a decade, but no ISSN update or initiative occurred. A natural extension for ISSN, the unique-identification of the articles in the serials, was the main demand application. An alternative serials' contents model arrived with the indecs Content Model and its application, the digital object identifier, as ISSN-independent initiative, consolidated in the 2000s. Only in 2007, ISSN-L was defined in the
DEF CON is one of the world's largest hacker conventions, held annually in Las Vegas, with the first DEF CON taking place in June 1993. Many of the attendees at DEF CON include computer security professionals, lawyers, federal government employees, security researchers and hackers with a general interest in software, computer architecture, phone phreaking, hardware modification, anything else that can be "hacked"; the event consists of several tracks of speakers about computer- and hacking-related subjects, as well as cyber-security challenges and competitions. Contests held during the event are varied, can range from creating the longest Wi-Fi connection to finding the most effective way to cool a beer in the Nevada heat. Other contests and present, include lockpicking, robotics-related contests, slogan, coffee wars, scavenger hunt and Capture the Flag. Capture the Flag is the best known of these contests, it is a hacking competition where teams of hackers attempt to attack and defend computers and networks using certain software and network structures.
CTF has been emulated at other hacking conferences as well as in military contexts. Federal law enforcement agents from the FBI, DoD, United States Postal Inspection Service, DHS via us-cert.gov and other agencies attend DEF CON. DEF CON was founded in 1993 by Jeff Moss as a farewell party for his friend, a fellow hacker and member of "Platinum Net", a Fido protocol based hacking network from Canada; the party was planned for Las Vegas a few days before his friend was to leave the United States, because his father had accepted employment out of the country. However, his friend's father left early, taking his friend along, so Jeff was left alone with the entire party planned. Jeff decided to invite all his hacker friends to go to Las Vegas with him and have the party with them instead. Hacker friends from far and wide got together and laid the foundation for DEF CON, with 100 people in attendance; the term DEF CON comes from the movie WarGames, referencing the U. S. Armed Forces defense readiness condition.
In the movie, Las Vegas was selected as a nuclear target, since the event was being hosted in Las Vegas, it occurred to Jeff Moss to name the convention DEF CON. However, to a lesser extent, CON stands for convention and DEF is taken from the letters on the number 3 on a telephone keypad, a reference to phreakers. Any variation of the spelling, other than "DEF CON", could be considered an infringement of the DEF CON brand; the official name of the conference includes a space in-between DEF and CON. Though intended to be a one-time event, Moss received overwhelmingly positive feedback from attendees, decided to host the event for a second year at their urging; the event's attendance nearly doubled the second year, has enjoyed continued success. In 2016, 22,000 people attended DEF CON 24. For DEF CON's 20th Anniversary, a film was commissioned entitled DEFCON: The Documentary; the film follows the four days of the conference and people, covers history and philosophy behind DEF CON's success and unique experiences.
In January 2018, the DEF CON China Beta event was announced. The conference was held May 11-13, 2018 in Beijing, marked DEF CON's first conference outside the United States; the Black Badge is the highest award. Capture the flag winners sometimes earn these, as well as Hacker Jeopardy winners; the contests that are awarded Black Badges vary from year to year, a Black Badge allows free entrance to DEF CON for life a value of thousands of dollars. In April 2017, a DEF CON Black Badge was featured in an exhibit in the Smithsonian Institution's National Museum of American History entitled "Innovations in Defense: Artificial Intelligence and the Challenge of Cybersecurity"; the badge belongs to ForAllSecure's Mayhem Cyber Reasoning System, the winner of the DARPA 2016 Cyber Grand Challenge at DEF CON 24 and the first non-human entity to earn a Black Badge. Since DEF CON 11, fundraisers have been conducted for the Electronic Frontier Foundation; the first fundraiser was an "official" event. The EFF now has an event named "The Summit" hosted by the Vegas 2.0 crew, an open event and fundraiser.
DEF CON 18 hosted. A notable part of DEF CON is the conference badge, which identifies attendees and ensures attendees can access conference events and activities; the DEF CON badge has been notable because of its changing nature, sometimes being an electronic badge, with LED's, or sometimes being a non-electronic badge such as a CD. Conference badges contain challenges or callback's to hacker or other technology history, such as the usage of the Konami Code in the DEF CON 24 badge, or the DEF CON 25 badge reverting to the look of the DEF CON 1 badge. DEFCON Badges do not identify attendees by name, however the badges are used to differentiate attendees from others. One way of doing this has been to have different badges, a general conference attendee badge, a Staff member, Speaker and other badges. In addition and organizations have begun creating their own badges in what has become known as badgelife; these badges may be purchased in many cases, or earned at the conference by completing challenges or events.
Some badges may give the holder access to after hours events at the conference. In 2018 the evolution of this came with what was termed SAO's; these were miniature PCB's that connected to the official and other badges that may extend fu
Physical security describes security measures that are designed to deny unauthorized access to facilities and resources and to protect personnel and property from damage or harm. Physical security involves the use of multiple layers of interdependent systems which include CCTV surveillance, security guards, protective barriers, access control protocols, many other techniques. Physical security systems for protected facilities are intended to: deter potential intruders, it is up to security designers and analysts to balance security controls against risks, taking into account the costs of specifying, testing, using, managing and maintaining the controls, along with broader issues such as aesthetics, human rights and safety, societal norms or conventions. Physical access security measures that are appropriate for a high security prison or a military site may be inappropriate in an office, a home or a vehicle, although the principles are similar; the goal of deterrence methods is to convince potential attackers that a successful attack is unlikely due to strong defenses.
The initial layer of security for a campus, office, or other physical space uses crime prevention through environmental design to deter threats. Some of the most common examples are the most basic: warning signs or window stickers, vehicle barriers, vehicle height-restrictors, restricted access points, security lighting and trenches. Physical barriers such as fences and vehicle barriers act as the outermost layer of security, they serve to prevent, or at least delay and act as a psychological deterrent by defining the perimeter of the facility and making intrusions seem more difficult. Tall fencing, topped with barbed wire, razor wire or metal spikes are emplaced on the perimeter of a property with some type of signage that warns people not to attempt to enter. However, in some facilities imposing perimeter walls/fencing will not be possible or it may be aesthetically unacceptable. Barriers are designed to defeat defined threats; this is part of building codes as well as fire codes. Apart from external threats, there are internal threats of fire, smoke migration as well as sabotage.
The National Building Code of Canada, as an example, indicates the need to defeat external explosions with the building envelope, where they are possible, such as where large electrical transformers are located close to a building. High-voltage transformer fire barriers can be examples of walls designed to defeat fire and fragmentation as a result of transformer ruptures, as well as incoming small weapons fire. Buildings may have internal barriers to defeat weapons as well as fire and heat. An example would be a counter at a police station or embassy, where the public may access a room but talk through security glass to employees in behind. If such a barrier aligns with a fire compartment as part of building code compliance multiple threats must be defeated which must be considered in the design. Another major form of deterrence that can be incorporated into the design of facilities is natural surveillance, whereby architects seek to build spaces that are more open and visible to security personnel and authorized users, so that intruders/attackers are unable to perform unauthorized activity without being seen.
An example would be decreasing the amount of dense, tall vegetation in the landscaping so that attackers cannot conceal themselves within it, or placing critical resources in areas where intruders would have to cross over a wide, open space to reach them. Security lighting is another effective form of deterrence. Intruders are less to enter well-lit areas for fear of being seen. Doors and other entrances, in particular, should be well lit to allow close observation of people entering and exiting; when lighting the grounds of a facility distributed low-intensity lighting is superior to small patches of high-intensity lighting, because the latter can have a tendency to create blind spots for security personnel and CCTV cameras. It is important to place lighting in a manner that makes it difficult to tamper with, to ensure that there is a backup power supply so that security lights will not go out if the electricity is cut off. Alarm systems can be installed to alert security personnel. Alarm systems work in tandem with physical barriers, mechanical systems, security guards, serving to trigger a response when these other forms of security have been breached.
They consist of sensors including motion sensors, contact sensors, glass break detectors. However, alarms are only useful. In the reconnaissance phase prior to an actual attack, some intruders will test the response time of security personnel to a deliberately tripped alarm system. By measuring the length of time it takes for a security team to arrive, the attacker can determine if an attack could succeed before authorities arrive to neutralize the threat. Loud audible alarms can act as a psycholo