Data Mining: Concepts, Models, Methods, and Algorithms

Data Mining: Concepts, Models, Methods, and Algorithms By Mehmed Kantardzic

Publisher: Wiley-IEEE Press; 2 edition 2011 | 552 Pages | ISBN: 0470890452 | EPUB | 9 MB

Now updated—the systematic introductory guide to modern analysis of large data setsAs data sets continue to grow in size and complexity, there has been an inevitable move towards indirect, automatic, and intelligent data analysis in which the analyst works via more complex and sophisticated software tools. This book reviews state-of-the-art methodologies and techniques for analyzing enormous quantities of raw data in high-dimensional data spaces to extract new information for decision-making.

This Second Edition of Data Mining: Concepts, Models, Methods, and Algorithms discusses data mining principles and then describes representative state-of-the-art methods and algorithms originating from different disciplines such as statistics, machine learning, neural networks, fuzzy logic, and evolutionary computation. Detailed algorithms are provided with necessary explanations and illustrative examples, and questions and exercises for practice at the end of each chapter. This new edition features the following new techniques/methodologies:

• Support Vector Machines (SVM)—developed based on statistical learning theory, they have a large potential for applications in predictive data mining

• Kohonen Maps (Self-Organizing Maps – SOM)—one of very applicative neural-networks-based methodologies for descriptive data mining and multi-dimensional data visualizations

• DBSCAN, BIRCH, and distributed DBSCAN clustering algorithms—representatives of an important class of density-based clustering methodologies

• Bayesian Networks (BN) methodology often used for causality modeling

• Algorithms for measuring Betweeness and Centrality parameters in graphs, important for applications in mining large social networks

• CART algorithm and Gini index in building decision trees

• Bagging & Boosting approaches to ensemble-learning methodologies, with details of AdaBoost algorithm

• Relief algorithm, one of the core feature selection algorithms inspired by instance-based learning

• PageRank algorithm for mining and authority ranking of web pages

• Latent Semantic Analysis (LSA) for text mining and measuring semantic similarities between text-based documents

• New sections on temporal, spatial, web, text, parallel, and distributed data mining

• More emphasis on business, privacy, security, and legal aspects of data mining technology

This text offers guidance on how and when to use a particular software tool (with the companion data sets) from among the hundreds offered when faced with a data set to mine. This allows analysts to create and perform their own data mining experiments using their knowledge of the methodologies and techniques provided. The book emphasizes the selection of appropriate methodologies and data analysis software, as well as parameter tuning. These critically important, qualitative decisions can only be made with the deeper understanding of parameter meaning and its role in the technique that is offered here.

This volume is primarily intended as a data-mining textbook for computer science, computer engineering, and computer information systems majors at the graduate level. Senior students at the undergraduate level and with the appropriate background can also successfully comprehend all topics presented here.

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Active networking

Active networking is a communication pattern that allows packets flowing through a telecommunications network to 

dynamically modify the operation of the network.

How it works

Active network architecture is composed of execution environments (similar to a unix shell that can execute active packets), a node operating system capable of supporting one or more execution environments. It also consists of active hardware, capable of routing or switching as well as executing code within active packets. This differs from the traditional network architecture which seeks robustness and stability by attempting to remove complexity and the ability to change its fundamental operation from underlying network components. Network processors are one means of implementing active networking concepts. Active networks have also been implemented as overlay networks.

What does it offer?

Active networking allows the possibility of highly tailored and rapid "real-time" changes to the underlying network operation. This enables such ideas as sending code along with packets of information allowing the data to change its form (code) to match the channel characteristics. The smallest program that can generate a sequence of data can be found in the definition of Kolmogorov complexity. The use of real-time genetic algorithms within the network to compose network services is also enabled by active networking.

Fundamental challenges

Active network research addresses the nature of how best to incorporate extremely dynamic capability within networks^[1].

In order to do this, active network research must address the problem of optimally allocating computation versus communication within communication networks^[2]. A similar problem related to the compression of code as a measure of complexity is addressed via algorithmic information theory.

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Wireless Andrew

Wireless Andrew was the first campus-wide wireless Internet network. Built in 1993^[1], it was located on the campus of Carnegie Mellon University at its Pittsburgh campus before Wi-Fi branding originated.^[2] [3]

Wireless Andrew is a 2-megabit-per-second wireless local area network connected through access points to the wired Andrew network, a high-speed Ethernet backbone linking buildings across the Carnegie Mellon campus. Wireless Andrew consists of 100 access points covering six buildings on the Carnegie Mellon campus. The university tested the current setup with over 40 mobile units before allowing general use by researchers and students in February 1997. ^[4]

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Technological evolution

Technological evolution is the name of a science and technology studies theory describing technology 

development, developed by Czech philosopher Radovan Richta

Theory of technological evolution

According to Richta and later Bloomfield,^[1][2] technology (which Richta defines as "a material entity created by the application of mental and physical effort to nature in order to achieve some value") evolves in three stages: tools, machine, automation. This evolution, he says, follows two trends: the replacement of physical labour with more efficient mental labour, and the resulting greater degree of control over one's natural environment, including an ability to transform raw materials into ever more complex and pliable products.

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Stages of technological development

The pretechnological period, in which all other animal species remain today aside from some avian and primate species was a non-rational period of the early prehistoric man.

The emergence of technology, made possible by the development of the rational faculty, paved the way for the first stage: the tool. A tool provides a mechanical advantage in accomplishing a physical task, and must be powered by human or animal effort.

Hunter-gatherers developed tools mainly for procuring food. Tools such as a container, spear, arrow, plow, or hammer that augments physical labor to more efficiently achieve his objective. Later animal-powered tools such as the plow and the horse, increased the productivity of food production about tenfold over the technology of the hunter-gatherers. Tools allow one to do things impossible to accomplish with one's body alone, such as seeing minute visual detail with a microscope, manipulating heavy objects with a pulley and cart, or carrying volumes of water in a bucket.

The second technological stage was the creation of the machine. A machine (a powered machine to be more precise) is a tool that substitutes the element of human physical effort, and requires the operator only to control its function. Machines became widespread with the industrial revolution, though windmills, a type of machine, are much older.

Examples of this include cars, trains, computers, and lights. Machines allow humans to tremendously exceed the limitations of their bodies. Putting a machine on the farm, a tractor, increased food productivity at least tenfold over the technology of the plow and the horse.

The third, and final stage of technological evolution is the automation. The automation is a machine that removes the element of human control with an automatic algorithm. Examples of machines that exhibit this characteristic are digital watches, automatic telephone switches, pacemakers, and computer programs.

It's important to understand that the three stages outline the introduction of the fundamental types of technology, and so all three continue to be widely used today. A spear, a plow, a pen, and an optical microscope are all examples of tools.

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Theoretical implications

The process of technological evolution culminates with the ability to achieve all the material values technologically possible and desirable by mental effort.

An economic implication of the above idea is that intellectual labour will become increasingly more important relative to physical labour. Contracts and agreements around information will become increasingly more common at the marketplace. Expansion and creation of new kinds of institutes that works with information such as for example universities, book stores, patent-trading companies, etc. is considered an indication that a civilization is in technological evolution.

Interestingly, this highlights the importance underlining the debate over intellectual property in conjunction with decentralized distribution systems such as today's internet. Where the price of information distribution is going towards zero with ever more efficient tools to distribute information is being invented. Growing amounts of information being distributed to an increasingly larger customer base as times goes by. With growing disintermediation in said markets and growing concerns over the protection of intellectual property rights it is not clear what form markets for information will take with the evolution of the information age..

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Insurance

In law and economics, insurance is a form of risk management primarily used to hedge against the risk of a contingent, uncertain loss. Insurance is defined as the equitable transfer of the risk of a loss, from one entity to another, in exchange for payment. An insurer is a company selling the insurance; an insured, or policyholder, is the person or entity buying the insurance policy. The insurance rate is a factor used to determine the amount to be charged for a certain amount of insurance coverage, called the premium. Risk management, the practice of appraising and controlling risk, has evolved as a discrete field of study and practice.

The transaction involves the insured assuming a guaranteed and known relatively small loss in the form of payment to the insurer in exchange for the insurer's promise to compensate (indemnify) the insured in the case of a financial (personal) loss. The insured receives a contract, called the insurance policy, which details the conditions and circumstances under which the insured will be financially compensated

Principles

Insurance involves pooling funds from many insured entities (known as exposures) to pay for the losses that some may incur. The insured entities are therefore protected from risk for a fee, with the fee being dependent upon the frequency and severity of the event occurring. In order to be insurable, the risk insured against must meet certain characteristics in order to be an insurable risk. Insurance is a commercial enterprise and a major part of the financial services industry, but individual entities can also self-insure through saving money for possible future losses.^[1]

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The Hardware Information Navigational Tool

The Hardware Information Navigational Tool, or HINT, is an information web service developed by the former AG Communications Systems (now Alcatel-Lucent) which displays hardware and software characteristics of a central office switching system. It displays the hardware equipment as it is positioned in the central office and shows how this equipment is being used. The program displays an interactive map, allowing the user to select the applicable states/provinces or country, then select the switching system, and then finally the module, circuit pack, and circuit. The statistical reports allow customers to maintain a watch on their resources. It is also useful for engineering and the daunting task of assigning all of the various telephony services.

All telephone exchanges are customized to local conditions. Because of this, there exists a dynamic difference between one central office to another due to capacity, provided features, and hardware vintages. HINT started out as an internal resource used by GTD-5 EAX Engineering Services, Remote Technical Assistance, and Sales Support. It was created with the intent to accurately view a customer’s unique hardware configuration without physically being present at the site. Deciphering the switch’s own Office Dependent Data (ODD), it provided switching system hardware images that were accurate and up-to-date. Through internal feedback and subsequent modifications, it evolved into a tool that was viable enough to be offered as a product and sought after by customers.

Due to the similarities between the GTD-5 EAX and the 5ESS product lines, numerous requests were made by HINT users to develop and expand the scope of HINT so that it includes the 5ESS switching system. After hearing the same request for several years and realizing the revenue potential of adding the 5ESS, AG expanded HINT to include the 5ESS switch type, providing the same features, look, and feel that has made the GTD-5 EAX version so popular.

Presently^[when?], over 90% of GTD-5 EAX switching systems are supported and maintained by the customer using HINT. These users have been using the tool for several years and purchase the service as a yearly subscription subject to annual scrutiny and review. Because of this, the vendor is continuously upgrading and adding new features to excite interest and retain its customer base.

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Area 51

Area 51 is a nickname for a military base located in the southern portion of Nevada in the western United States (north-northwest of Las Vegas). Situated at its center, on the southern shore of Groom Lake, is a large military airfield and one of the most secretive places in the world. The base's primary purpose is to support development and testing of experimental aircraft and weapons systems.

The base lies within the United States Air Force's vast Nevada Test and Training Range. Although the facilities at the range are managed by the 99th Air Base Wing at Nellis Air Force Base, the Groom facility appears to be run as an adjunct of the Air Force Flight Test Center (AFFTC) at Edwards Air Force Base in the Mojave Desert, around 160 miles (260 km) from Groom, and as such the base is known as Air Force Flight Test Center (Detachment 3). Area 51 researcher Glenn Campbell claims that AFFTC Detachment 3 is located at Groom, citing the title of a leaked security manual, the mailbox in Henderson, Nevada he believes formerly served Groom, and the NASA biography of astronaut Carl E. Walz who was formerly a manager at AFFTC detachment 3 (AFFTC-DET3.)

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IZArc (known as IZip)

IZArc (known as IZip) is an archiving tool suports many archive formats like: 7-ZIP, A, ACE, ARC, ARJ,B64, BZ2, BH, CAB, BZA, CPIO, ENC, DEB, GCA, GZ, GZA, HA, JAR, LHA, LIB, LZH, MBF, MIM, PAK, PK3, RAR, RPM, TAR, TAZ, TBZ, TGZ, TZ, UUE, XXE, YZ1, Z, ZIP, ZOO

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How to Fix a Slow Running Computer

Finding your computer isn't running as though it is shiny and new? If so, then you definitely are in the right place. There are many reasons for a slow running computer, and having the proper knowledge, will definitely help you to remedy the problem.
Main Causes of a Slow Running Computer
Virus, Spyware or Malware infection
Windows Registry Problems
Severely fragments hard disk
Not enough hard drive space
The first four reasons are fairly easy to solve. To determine if you have spyware, malware or virus infection, simply scan for malware. To determine if you have a windows registry problem, then use a registry cleaner that will safely scan your computer's registry for errors, and automatically repairs them for you. If the problem is that you need more hard disk, then you can remove temporary files and unwanted programs or flies and run a disk cleanup utility. If your problem is that your hard disk is fragmented, then you will need to defragment your computer.
Other Reasons Your Computer May Be Running Slow
When you are running too many programs at once, your computer will slow down. Close some of them to determine if that is what you are experiencing.
If you are doing tasks such as watching movies, DVD burning, editing graphics, etc. these tasks may result in a slower running computer, as the demands on the computer's system is greater.
Corrupt or misbehaving programs. Files can become corrupt, and when they do, they will cause havoc on your computer.
Another cause may be that your computer does not have enough RAM. RAM stand for Random Access Memory and is your computer's memory. When you are short on RAM upgrading your PCs RAM will enhance its performance.
One major cause of a slow running computer is too many unnecessary programs which automatically load when the computer starts. By disabling these computer programs, you will improve the speed of your computer.
Also, your computer may be overheating. Check the fans to see if they are functioning properly. If for some reason, they are not, it will be necessary to replace or repair the fan unit.
The technology of a computer is a science, and it is proper to have the proper information. Learning how to prevent, and diagnose a slow computer is not something that takes a rocket scientist. There are easy to learn computer fixes that will help you to get your computer in prime running condition, once again, and save you the expense of a computer technician to troubleshoot and repair the problem.
Also, you should always practice maintenance with your computer. This means giving your computer regular tune ups. PC Tune up software is one of the easiest ways to fix endless computer problems and keep your PC in top running shape. By taking the necessary preventative measures, you will keep your computer in top running speed and have fewer problems as the software will help to eliminate the many problems associated with the operation of a computer.

Get all the answers you need on how to fix a slow running computer at www.howtomakecomputerfaster.net.

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A Face-Saver For The iPhone Police

Apple's newest iPhone, the 4S, has been on the market for a few weeks, but the saga surrounding the leak of a prototype of the previous-generation iPhone 4 is only now coming to a close.
Brian Hogan and Sage Wallower pleaded no contest to a misdemeanor charge of theft of lost property for selling a phone that an Apple tester accidentally left in a bar. The two men, both in their 20s and with no previous criminal records, each received a year of probation and 40 hours of community service. They were also ordered to pay Apple restitution of $250.
According to technology blog Gizmodo.com, it all started when Apple engineer Gray Powell headed out to celebrate his 27th birthday at a German beer garden. Powell accidentally left his phone at the bar. A forgotten phone isn't usually a newsworthy event - unless, of course, the phone involved is a top-secret design produced by one of the world's most notoriously close-mouthed technology companies, cleverly disguised as a run-of-the-mill older model. Which is exactly what Powell's phone was. (1)
Hogan, who was also at the beer garden that night, took the phone home, not realizing its true importance. He intended to return it the next day. Once he discovered what he had, he tried to contact Apple. His calls were ignored. Next, he and Wallower checked to see if perhaps a technology media outlet might take their story more seriously. Gizmodo, which is owned by Gawker Media LLC, listened. It offered $5,000 for the device. The site proceeded to post photos and conjectures about the new phone. Its software had been remotely disabled, but that didn't stop the enterprising editors from examining the hardware. Gizmodo says that when it was asked to return the phone, it immediately arranged to do so.
Apple, however, may not have been satisfied with just getting its phone back. The company, which keeps most of its prototypes bolted to desks in its super-secured campus, was not happy about photos of its upcoming product being splayed all over the Internet. Much of that displeasure was likely directed at Jason Chen, a Gizmodo editor who reported on the dissected phone's innards.
California's Rapid Enforcement Allied Computer Team (REACT) - Silicon Valley's high-tech police - raided Chen's home on the authority of a search warrant issued by San Mateo County Superior Court Judge Clifford V. Cretan. Officers left with a pile of computers and hard drives; Chen was left with a broken door.
Like others at the time, I believed the search to be illegal. While others invoked California's shield laws, which offer special protections for journalists, I saw no reason why anyone, journalist or not, should have been subject to a search when the evidence that any crime had actually been committed was minimal at best.
Eventually, the search warrant was withdrawn, which is a pretty good indication that it should not have been issued in the first place, and Chen's property was returned. Conveniently for Apple, however, Chen didn't get his computers and other research materials back until after the iPhone 4 was safely on the market.
Neither the men who sold the phone nor the journalist did anything obviously wrong in this case. Apple apologists (and government lawyers defending any lawsuits by Chen and Gizmodo, who were never charged) will claim the misdemeanor guilty pleas as evidence that justice, as well as beer, is served in Silicon Valley. If you believe this, I have an old IBM PCjr to sell you that will work just great as a server for your website.
Hogan and Wallower faced a pretty easy choice: They could take a slap on the wrist and get on with their lives, or they could run up a fortune in legal fees (which not every 20-something in Silicon Valley can afford) and risk felony convictions that would ruin their prospects for security clearances and job opportunities. Don't confuse justice with expediency.
REACT needs reform, and the San Mateo County bench could do with a little review on the legal and ethical hazards of being a hometown judge.
There were concerns about REACT long before the iPhone incident. The task force's website states that the organization "depends on our industry partners," who provide know-how and other support. After the iPhone raid, Nick Muyo, the public information officer of the Santa Clara County district attorney's office, told the Los Angeles Times that technology companies, including Apple, "have open invitations" to attend meetings of REACT's steering committee, and that many companies send representatives. (2)
Letting law enforcement get too cozy with private industry can lead to an erosion of professional judgment. Someone needed to tell Apple that interference with the choreography of its product rollouts is not a crime, and that journalists' homes and hard drives are not reference libraries.
Of course, there is another important lesson in this story: Don't take corporate secrets into a bar. According to some reports about a missing iPhone 4S in August, Apple may not have learned that one.
This time, however, no search warrants were issued. Apple's latest gizmo is nevertheless selling quite well.

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Can Androids and Human Be Friends?

Is there any other choice?

Today's androids are showing up more human-appearing. They're constructed with new age materials, with artificial intelligence, using faster and more powerful computers. They're, all around, more talented and capable robots, embedded with new technologies. But where do you draw the line dividing the use of 'droids in life and in the workplace, from skilled human workers? So called unskilled workers for that matter. Already we're hearing warnings like: "Don't eat food prepared by a 'droid who can't taste it."

Could we reach a computer runaway, where androids take over, driving humans from all levels of society, including the rich and powerful, to the homeless, and everyone in the middle? Would this be good for humankind? Obviously not.

What if the androids did all the work, and the people all lived like kings from their labors? Would this be better? Initially maybe. But what if the 'droids took an unusual turn, due to the law of unexpected consequences? Maybe because of a mistake in their programming or contradiction in their perceived mandate. Maybe because over-population isn't good for us. How would this all turn out? Uncertain and real scary. Maybe it would end up in the first case anyway: an android takeover. Say you could live like a king if you spent all your waking moments trying to jump through impossible hoops; no joy there. Or maybe your 'droid servants would come to the conclusion ecotopia was best for you, and we'd all be living in the woods and as hunter-gatherers. Still having the title of king, of course. Not so good for the majority-a few would probably think it was great. They could live an idyllic life, unencumbered by technology intrusions: no phone calls, no utility bills, no computer problems, and no television - gulp.

In either case 'droids would be ascendant and humans would be in a bad way, even a threatened species. All 7 billion of us. The point is: Would the downfall of humanity be good for the androids? Not really. Why? Because it's unlikely that 'droids could make significant progress without that spark of human intelligence making it happen. Hopefully the androids would know this before things got too bad for humans. Or better, far-sighted human developers and programmers would instill this into androids in the first place. A lot of thought and adjustments would have to be made along the way. Obviously androids would have to live like humans: working jobs (or jobless) saving money, buying homes (or living with the homeless), paying utility bills, seeing professionals, and even doing travel and taking vacations.

Copyright: Stanley Gerson, 2011

The new book iSly, is a fresh look at real androids, fitted to live and work in society. eSly is an environmental and economic saving android race. But it all goes wrong when iSly spontaneously shifts out from eSly, starts to replicate himself, and goes on his own, sinister mission. World leaders are horrified. A resurgent Joseph Dane is on the case, with Bluegrass, his colorful sidekick, and TatarKhan, Hypernet Master. They pursue a dangerous, last ditch effort to find the cause of this 'droid disaster, and to help a chastened humanity find a new future.
Why not have a look at iSly, the new book by Stanley Gerson. Just click on this link: http://www.islydroids.com/

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The Basics of CISCO Password Management

Cisco is a system that many people take months or even years to fully learn. Thus, many people that are using this often feel as though they have to call in a professional for everything that they may need. However, when it comes to Cisco password the person is going to find that they can change this and make it better for their security, even if they are not the most computer savvy person that is out there.
First things first, the Cisco password is by default one that is going to use an Enable password, which is not helping to protect your router at all and is something that anyone with a little bit of knowledge can break into. Which is why, for security purposes, the person should be sure that they are changing this to an Enable Secret password.
To do this, the person must go into the Privileged Exec mode, which is going to allow them to have access to change the password. They are going to need a series of commands in order to do this, and this is something that they can find through various sources, such as forums and books. Once you think that you have this complete, try it out to make sure that it has taken.
The main question that most people have is how they would go about getting the password to work should they forget it or they were not the ones to program this in the first place. When this happens, first off, the person should not panic. The Cisco system was designed for a way to get around this, so it is possible to do this.
The person will want to get into ROM monitor mode which means that they will have to connect to the router through the actual port instead of wireless. Once they have done this the mode that they enter is basically the go to mode for when passwords are lost or are forgotten.
The rest of the procedure is completed according to what type of route that you have working for you. Thus, the person must consult the Cisco website to find distinct and clear instructions for their particular router. Using the wrong instructions will only lengthen the time it takes to get the router up and running again.
In most cases, once the person changes anything that is security like, including the passwords, they are going to find it best to restart the router in order to ensure that everything takes and the new security field is up and running. If they do not do this, they may find that they are putting their network at risk without taking these precautions.

Overall, changing the password to ensure the most security for your router is something that all Cisco users should do. They are going to find that this is rather simple and if they are ever in need of help there are many sources at their disposal such as http://www.firewall.cx which can be a huge source of information pertaining to Cisco.
Need more information on Cisco password management? Then visit Firewall.cx, a globally recognized site covering networking topics, protocol analysis, Cisco routing, switching, security and VoIP technologies.

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Discrete mathematics

Discrete mathematics is the study of mathematical structures that are fundamentally discrete rather than continuous. In contrast to real numbers that have the property of varying "smoothly", the objects studied in discrete mathematics – such as integers, graphs, and statements in logic^[1] – do not vary smoothly in this way, but have distinct, separated values.^[2] Discrete mathematics therefore excludes topics in "continuous mathematics" such as calculus and analysis. Discrete objects can often be enumerated by integers. More formally, discrete mathematics has been characterized as the branch of mathematics dealing with countable sets^[3] (sets that have the same cardinality as subsets of the natural numbers, including rational numbers but not real numbers). However, there is no exact, universally agreed, definition of the term "discrete mathematics."^[4] Indeed, discrete mathematics is described less by what is included than by what is excluded: continuously varying quantities and related notions.

The set of objects studied in discrete mathematics can be finite or infinite. The term finite mathematics is sometimes applied to parts of the field of discrete mathematics that deals with finite sets, particularly those areas relevant to business.

Research in discrete mathematics increased in the latter half of the twentieth century partly due to the development of digital computers which operate in discrete steps and store data in discrete bits. Concepts and notations from discrete mathematics are useful in studying and describing objects and problems in branches of computer science, such as computer algorithms, programming languages, cryptography, automated theorem proving, and software development. Conversely, computer implementations are significant in applying ideas from discrete mathematics to real-world problems, such as in operations research.

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Number theory

 

Number theory

 

Number theory is a branch of pure mathematics devoted primarily to the study of the integers. Number theorists study prime numbers (the building blocks of integers) as well as the properties of objects made out of integers (such as rational numbers) or defined as generalizations of the integers (such as, for example, algebraic integers).

Integers can be considered either in themselves or as solutions to equations (diophantine geometry). Questions in number theory are often best understood through the study of analytical objects (e.g., the Riemann zeta function) that encode properties of the integers, primes or other number-theoretic objects in some fashion (analytic number theory). One may also study real numbers in relation to rational numbers, e.g., as approximated by the latter (diophantine approximation).

The older term for number theory is arithmetic; by the early twentieth century,^[1] it had been superseded by "number theory". (The word "arithmetic" is used by the general public to mean "elementary calculations"; it has also acquired other meanings in mathematical logic, as in Peano arithmetic, and computer science, as in floating point arithmetic.) The use of the term arithmetic for number theory regained some ground in the second half of the 20th century, arguably in part due to French influence.^[2] In particular, arithmetical is preferred as an adjective to number-theoretic

Algebraic number theory

 

 

Algebraic number theory studies algebraic properties and algebraic objects of interest in number theory. (Thus, analytic and algebraic number theory can and do overlap: the former is defined by its methods, the latter by its objects of study.) A key topic is that of the algebraic numbers, which are generalizations of the rational numbers. Briefly, an algebraic number is any complex number that is a solution to some polynomial equation with rational coefficients; for example, every solution x of (say) is an algebraic number. Fields of algebraic numbers are also called algebraic number fields.

It could be argued that the simplest kind of number fields (viz., quadratic fields) were already studied by Gauss, as the discussion of quadratic forms in Disquisitiones arithmeticae can be restated in terms of ideals and norms in quadratic fields. (A quadratic field consists of all numbers of the form , where a and b are rational numbers and d is a fixed rational number whose square root is not rational.) For that matter, the 11th-century chakravala method amounts—in modern terms—to an algorithm for finding the units of a real quadratic number field. However, neither Bhāskara nor Gauss knew of number fields as such.

The grounds of the subject as we know it were set in the late nineteenth century, when ideal numbers, the theory of ideals and valuation theory were developed; these are three complementary ways of dealing with the lack of unique factorisation in algebraic number fields. (For example, in the field generated by the rationals and , the number 6 can be factorised both as and ; all of 2, 3, and are irreducible, and thus, in a naïve sense, analogous to primes among the integers.) The initial impetus for the development of ideal numbers (by Kummer) seems to have come from the study of higher reciprocity laws,^[12] i.e., generalisations of quadratic reciprocity.

Number fields are often studied as extensions of smaller number fields: a field L is said to be an extension of a field K if L contains K. (For example, the complex numbers C are an extension of the reals R, and the reals R are an extension of the rationals Q.) Classifying the possible extensions of a given number field is a difficult and partially open problem. Abelian extensions—that is, extensions L of K such that the Galois group^[13] Gal(L/K) of L over K is an abelian group—are relatively well understood. Their classification was the object of the programme of class field theory, which was initiated in the late 19th century (partly by Kronecker and Eisenstein) and carried out largely in 1900—1950.

An example of an active area of research in algebraic number theory is Iwasawa theory. The Langlands program, one of the main current large-scale research plans in mathematics, is sometimes described as an attempt to generalise class field theory to non-abelian extensions of number field

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what is Technology

Technology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures. The word technology comes from Greek τεχνολογία (technología); from τέχνη (téchnē), meaning "art, skill, craft", and -λογία (-logía), meaning "study of-".^[1] The term can either be applied generally or to specific areas: examples include construction technology, medical technology, and information technology.

Technologies significantly affect human as well as other animal species' ability to control and adapt to their natural environments. The human species' use of technology began with the conversion of natural resources into simple tools. The prehistorical discovery of the ability to control fire increased the available sources of food and the invention of the wheel helped humans in travelling in and controlling their environment. Recent technological developments, including the printing press, the telephone, and the Internet, have lessened physical barriers to communication and allowed humans to interact freely on a global scale. However, not all technology has been used for peaceful purposes; the development of weapons of ever-increasing destructive power has progressed throughout history, from clubs to nuclear weapons.

Technology has affected society and its surroundings in a number of ways. In many societies, technology has helped develop more advanced economies (including today's global economy) and has allowed the rise of a leisure class. Many technological processes produce unwanted by-products, known as pollution, and deplete natural resources, to the detriment of the Earth and its environment. Various implementations of technology influence the values of a society and new technology often raises new ethical questions. Examples include the rise of the notion of efficiency in terms of human productivity, a term originally applied only to machines, and the challenge of traditional norms.

Philosophical debates have arisen over the present and future use of technology in society, with disagreements over whether technology improves the human condition or worsens it. Neo-Luddism, anarcho-primitivism, and similar movements criticise the pervasiveness of technology in the modern world, opining that it harms the environment and alienates people; proponents of ideologies such as transhumanism and techno-progressivism view continued technological progress as beneficial to society and the human condition. Indeed, until recently, it was believed that the development of technology was restricted only to human beings, but recent scientific studies indicate that other primates and certain dolphin communities have developed simple tools and learned to pass their knowledge to other generations

source: wikipedia

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Common sense for smart phone security

Smartphones have done wonderful things for employee mobility, but they have also complicated the security picture at organizations large and small. Where most companies used to limit smartphone use to one platform, such as Research In Motion’s Blackberry, most now cope with multiple smartphone models, platforms, and operating systems, each with its own quirks and vulnerabilities. Add the growing number of employees expecting to use the same device at home and work and things get even dicier.

However, there are steps you can take to secure smartphone use. As usual, they involve education, policy, and technology.

If you allow multiple smartphone platforms, such as iOS, Android, and Windows 7, it’s important to educate users on the security challenges these devices bring to the organization and the proper measures users must take to address them. Users should be educated about the dangers of device theft, data theft, data leakage, and malware and the financial impact they can have on the business. Include some actual use cases and anecdotes that demonstrate just how damaging smartphone breaches can be, and keep users aware of publicized, damaging breaches as they come up. Education should be repeated at least once a year and new employees should be educated immediately to the dangers as well as the company policies related to mobile devices.

Policy is the second obvious defense. Most policies should at least require users to:

• Keep smartphones within their sight at all times
• Activate phone locking after a period of inactivity and use strong passwords or PINs for reactivation
• Back up smartphone applications and content regularly
• Report smart phone theft immediately so remote locking or remote wiping can be activated
• Avoid using smartphones over insecure Wifi networks
• Connect from smartphone to the corporate network over secure VPN’s
• Encrypt all corporate information stored on the phone using provided tools
• Keep Bluetooth out of discovery mode when not in use
• Avoid clicking on links in SMS messages
• Make it clear that no jailbroken phones will be allowed in the organization.

When it comes to malware, things get a bit more complicated. Some smartphone platforms have malware protection software available and some don’t. Even for those that do, the applications are relatively new.

One way to reduce the threat of malware is to educate users on what to look for when downloading new applications. For example, Android displays all the permissions a new application is seeking on the device. Users should be taught to look out for applications that seek access to things like contacts or location unnecessarily and to carefully read user application ratings before downloading. Some companies might want to provide their own online store of pre-approved applications. Users should submit any other applications to the store minders to ensure their safety.

(Source:McAfee)

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Make Yours A First Rate Job With Teng Tools

When anyone attempts a job, maintenance work or possibly a construction project, they really want the result to be the very best that it can possibly be. When the ideal outcome is not attained after much effort has been invested, one can be left feeling negative and hopeless. This would be an awful shame, and in some cases where such things happen, the blame does not lie with the workman for not working correctly. Often, most of the hard work dedicated to a project can be perfectly executed and the result may still be far from perfect. What’s the reason behind this? This could commonly occur because of tools being used which are simply unsuitable to do the job in hand or they may be of a low quality. This may be a horrendous shame if the only thing stopping the required result being achieved with a job would simply be the type of tool used. So what is the solution to ensure that the tool you select is suitable for the job in hand and is of a sufficient quality to finish a job to a high standard? This can be attained through using Teng tools.

Some of the best quality tools available today are produced and distributed by Teng tools. They offer a variety of over 1800 tools making sure that everybody can find the correct tool they require for the task they need to do. Teng tool currently supply tools to various large organisations within the aviation industry and the automotive engineering industry. Anyone may purchase Teng tool products so as to complete DIY projects to a high standard. Teng tools are so assured of the superior quality of their tools, each and every one purchased includes a lifetime guarantee. The product range of Teng tools in the marketplace is extensive and therefore means that for anybody who must undertake a project, be it car maintenance or a home DIY project, there are Teng tools designed to help one finish the job to the highest quality and standard possible.

The Teng tool name was taken from a Japanese folk hero from the 12th century who had been well known for his power and control. It’s these features which Teng tools try and embody in each and every tool they produce. Teng tools give you the right level of power and control to complete a job to a high standard. With the help of customer feedback Teng tools seek to be continually improving the tools that they make.

With Teng tools, it is no longer necessary to feel unhappy with a finished result or feel hopeless when a DIY project has not matched up to original goals. With this brand of tool, you are able to come away from any project or job with pride and the result that was desired and expected of a job being done with Teng tools.

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Renowned Steve Jobs Passed Away

yesterday’s announcement of the iPhone 4S, Apple co-founder and former CEO Steve Jobs has died. Jobs had fought a long battle with a rare form of pancreatic cancer, and after seeking treatment across the world, he has fallen to the illness at the age of 56.

Jobs passed away today, October 5, just one day after the debut of the next generation iPhone. The iPhone, introduced in June of 2007, launched the mainstream smartphone revolution and is arguably Jobs’ greatest achievement at Apple.

According to Apple’s official website: “Apple has lost a visionary and creative genius, and the world has lost an amazing human being. Those of us who have been fortunate enough to know and work with Steve have lost a dear friend and an inspiring mentor. Steve leaves behind a company that only he could have built, and his spirit will forever be the foundation of Apple.“

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