Development economics is a set of public and private practices encouraging the economic development of a country or region, promoting the propensity to invest, innovate, initiate, train, work.

Development economics as a full-fledged branch of the economy, from the end of World War II. Earlier studies on poor countries were part of the analysis of growth. There were no specific theories for these countries. It was only in the fifties that economists will seek to develop tools specific to developing countries.

The early work of pioneers in the development did not distinguish between economic development and economic growth. Development necessarily means obtaining economic growth over a long period. And conversely any growth would improve the well-being of the population and reducing poverty. The work is therefore interested in the determinants of growth. The first focused on policies advocated a massive investment to overcome under-development and implementation of a virtuous circle. Thereafter development economists have introduced the separation between development and growth. Development cannot occur without growth, but development policy should focus also on reducing inequalities, basic needs…

Means of Development

Practices that foster development can be located at the legal provisions, the adaptation of infrastructure and education, and even some financial incentives. Solow closely examined these aspects, as well as government agencies (World Bank) or private (Soros Foundation) responsible for promoting development.

The transition between an underdeveloped economy and a developing economy requires a sufficient accumulation exceeding a critical initiative, adaptation cultural, educational, and legislative and material resources. In particular, examples of emerging countries , including the largest in population, such as China , the India and Brazil have shown that the economic takeoff was facilitated by the introduction of measures falling within the economic framework Keynesianism such as infant industry protection, enhanced export credit and investment, structural maintenance of an exchange rate much lower than the purchasing power parity of their currencies, the existence of a public sector and the relatively high level of social investment and human voluntary policies of agrarian reform especially in East Asia, education, health, improving the status of women and the possibility of access to contraception. These interventionist measures were completed mainly from the years 1970 to 1980 by a liberalization of private initiatives under the economic liberalism.

Initiation of development: places and sectors

Concerning the nature and location of projects primer can be distinguished:

• development from the bottom up, from micro-projects very localized, involving people and trusting his initiative,
• And development from major investment projects which, although necessary and, for some, indispensable, can affect more random and less “catchy” for the rest of the economy.

Modern theories of development (Michael Porter) also insist on the notion of competence center geographically, which include know-how providing excellence source of competitive advantage. The pivot can be a university with a research center renowned and highly motivated by cooperation with economic and financial entities. Two examples:

• The Silicon Valley includes three competencies: academic (Stanford, Berkeley, Santa Clara), technology companies (the first was Hewlett-Packard) and fund capital risk.
• Emerging countries such as India (Bangalore, Mumbai for outsourcing software and active ingredients for generic drugs), China (space industry) and Brazil (agricultural genetic) play a number of activities over conventional unskilled labor, this role in the field of advanced technology.

The Millennium Development

In September 2000 at the Millennium Summit, the political leaders of the world, under the auspices of the United Nations agreed to a set of measurable objectives called the Millennium Development, to be achieved by in 2015. These objectives are: Halving extreme poverty and hunger Reduce by three quarters the maternal mortality Achieve universal primary education for all; Fight diseases, especially HIV / AIDS and malaria; Promote gender equality and empower women; Ensure environmental sustainability: Reduce by two thirds the mortality of children under 5 years Develop a global partnership for development. These objectives require a strong social commitment.

Changing patterns of development

Sustainable development

Some advocate sustainable development or sustainable growth, managing of sparingly everything natural resources, some of which may dry or deteriorate.

Management is certainly necessary. The modern economy, called post-industrial economy has become more sophisticated. It comes from the knowledge economy, which is one of the determinants of the education, the information, expertise and innovation.

In fact, despite the advent of the knowledge economy, it is the developed countries continue to be dependent on natural resources. Emerging countries will in turn pass through an industrial phase, and consume more resources. Studies show that the activities of services and high-tech sectors (software, telecommunications networks) also consume raw materials and energy.

In any case, the sustainable development is seen as a goal for humanity and it determines the living conditions of future generations.

The Issue Of Model Development

When President Harry Truman presented his program to help countries “underdeveloped” in his inaugural speech in 1949, he proposed to make the technical knowledge of the United States and other developed areas of the world less advanced. This implicitly assumed that the lifestyle of the United States and other Western countries could inspire the development of the rest of the world, he was a model. These designs have ensured the triumph of a vision econometric development, in which the level of States’ progress was measured by a single indicator, the GDP per capita.

Since the 2000s, NGOs, headed by the WWF, advanced the idea that the environmental impact of the activities of the most “developed” (North America, Europe), measured by the ecological footprint was very than the biological capacity of the planet. For these organizations, the Western type of development cannot be generalized as such to the whole world. Experts such as Jean-Marc Jancovici also think it is unrealistic to propose to the world a model such as that inherited from the Industrial Revolution, the use of fossil fuels in particular with a much too strong impact on climate.

Alternatives are proposed since the 1990s. With the emergence of the concept of sustainable development, it seeks to balance the effect of economic, environmental, and social development. However, to say that sustainable development provides one model would be presumptuous. First, because it is so far above a target and actions are struggling to keep the good words. Secondly, because the development assistance must comply with the cultural specificities of the countries assisted, as UNESCO pointed at the Earth Summit in Johannesburg in 2002.

This is the problem the oldest and most studied video indexing, considered an essential building block for analysis and research videos. There are so far little direct applications of segmentation plans for the general public, or software digital video. However, this is a major step in the analysis of the video, allowing the definition and use of technical information retrieval in videos.

The shot segmentation is to identify the different shots of a video. This only makes sense if the video actually contains plans, that is to say, it was fitted by a director. Some types of videos (video surveillance, home videos …) do not lend themselves to this type of technique. The videos are generally considered to movies or shows television.

The shot segmentation is sometimes (incorrectly) called “segmentation scenes” two by some researchers. The segmentation into scenes however, is a different task, which is to identify the scenes; this concept is defined as a group sharing plans semantic consistency.

Different types of transitions between shots

There are many ways to make a transition between two planes. The simplest is the abrupt transition: moving from one plan to another without image transition. To make this more flexible way, the filmmakers have created a wide variety of smooth transitions, the fade to black, fades, the shutters, and many others, made ​​easier by the use of computer and even consumer software video editing.

For shot segmentation, researchers generally distinguish two types: abrupt transitions (also called cuts, the English “cut”) and gradual transitions, which include all other types of transitions.

Methods

The main idea underlying the shot segmentation methods is that the images in the vicinity of a transition are very dissimilar. We then seek to identify discontinuities in the video stream.

The general principle is to extract an observation on each image, and then define a distance 9 (or similarity measure) between observations. The application of the distance between two successive images, the entire video stream, producing a one-dimensional signal, in which then seeks the peaks (resp. if hollow similarity measure), which correspond to the moments of high dissimilarity.

 Observations and distances 

The simplest observation is simply the set of pixels of the image. For 2 frames  and  N × M, the apparent distance is then the average of the absolute differences pixels pixels (distance L1):

 More refined approaches can measure only significant changes, filtering the pixels that generate differences too low, that only add noise.

Unfortunately, the techniques in the field pixellic are very sensitive to movements of objects or camera. Techniques of block matching have been proposed to reduce the sensitivity to motion, but the methods in pixellic were largely supplanted by methods based on histograms.

The histogram of luminance or color, is a widely used observation. It is easy to calculate, and is relatively robust to noise and movement of objects, because a histogram ignores the spatial changes in the image.

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After the information has been recorded digitally, we wanted to know how much information is contained in an actual message. This question is both philosophical, as well as technical engineering interest. The engineering questions answered Claude Elwood Shannon (father of information theory) with his famous work A Mathematical Theory of Communication. It was in 1949 under the title The Mathematical Theory of Communication easily expanded and republished.

After over 50 years of information theory, there is no area that has not been touched by the information theory, and there is no area that will sooner or later have to deal not with the encoding and compression of data or information.

Data compression is commonly used when, for example, be transmitted in a specific amount of data per unit of time must or the absolute amount of data is critical. A certain amount of data transmitted per unit of time is called channel capacity, and this capacity is finite. This means that a finite number of information per unit of time can be transmitted, and that in turn means that no information can be transferred exactly infinite.

• Radio transmission routes (BOS, Tetra radio)
• DVB-C (digital cable television),
• DVB-S (digital satellite TV)
• DVB-T (digital terrestrial television),
• DAB (digital audio broadcasting),
• Mobile (digital terrestrial and satellite telephony),
• Internet telephony

Of an insufficient channel capacity it is often, when it is dependent on a certain amount of transmitted data per unit time over a limited channel or the channel is narrowband. It may happen that only a part of the information can be transmitted. The wireless standard GSM is one such example. A GSM channel error protection features including approximately 9.6 kilobits / second. The data rate of an audio CD (stereo) is about 1500 kilobits / second. This means that an audio CD cannot be in “real time” transferred by means of a GSM channel. For each second CD data material for about 2 minutes and 30 seconds on a GSM channel transmission time would be needed. The only way the real-time transmission is to process the data CD-material so that the recipient can get a sense of the contents of the CD. That means you try to transfer the most important piece of information.

An improved economy will be achieved if we can reduce the amount of data by data compression and data reduction before it transfers to the disk / memory. This allows more data to be stored from the original material. The memory can store a certain amount of data (capacity), and it does not matter whether the data store redundant or non-redundant data. Preference stores not redundant information on the hard disk or data storage. Thus need fewer disks / data storage are purchased / leased. Normally the data storage and data retention costs to fall further in the form of electricity for the computer and especially for air conditioning. This also applies to data which have been stored on magnetic tapes. These must be stored above all where they are not exposed to changing environmental conditions.

The disadvantage of the optimal representation of the data is present in particular if the data must be processed consuming to obtain the coded or un-coded form of the data. Most of the currently known methods of complex audio, video and image coding require complex mathematical models and transformations to code them or to make them usable again for the people. Other methods come out with less mathematical complexity and cannot encode it efficiently or effectively enough. This means that we must find a compromise between computing / processing time and coding of data. The more one can identify dependencies between the individual data to be encoded, the more efficient the data can be encoded.

There are a number of examples, the basis of which it can be shown that the lossless or lossy compression data are meaningful. Data compression is closely related to the information theory, as formulated by Claude Shannon in 1948. Information theory and the information theoretical approaches have after 50 years of existence touched so many areas that the modern computer science and information technology inconceivable without this theoretical treatise would. Today it is more than ever in order to store and process digital data and it does not matter which way you look. Modern medicine today comes not from without image-processing methods. After the information has been digitally, they were looking for ways to transfer it also digitally and stored digitally and processed digitally. Only in this way it was possible to process information digitally and thus loss or copy.

After the information has been recorded digitally, we wanted to know how much information is contained in an actual message. This question is both philosophical, as well as technical engineering interest. The engineering questions answered Claude Elwood Shannon (father of information theory) with his famous work A Mathematical Theory of Communication. It was in 1949 under the title The Mathematical Theory of Communication easily expanded and republished.

After over 50 years of information theory, there is no area that has not been touched by the information theory, and there is no area that will sooner or later have to deal not with the encoding and compression of data or information.

Data compression is commonly used when, for example, be transmitted in a specific amount of data per unit of time must or the absolute amount of data is critical. A certain amount of data transmitted per unit of time is called channel capacity, and this capacity is finite. This means that a finite number of information per unit of time can be transmitted, and that in turn means that no information can be transferred exactly infinite.

·         Radio transmission routes (BOS, Tetra radio)

·         DVB-C (digital cable television),

·         DVB-S (digital satellite TV)

·         DVB-T (digital terrestrial television),

·         DAB (digital audio broadcasting),

·         Mobile (digital terrestrial and satellite telephony),

·         Internet telephony

Of an insufficient channel capacity it is often, when it is dependent on a certain amount of transmitted data per unit time over a limited channel or the channel is narrowband. It may happen that only a part of the information can be transmitted. The wireless standard GSM is one such example. A GSM channel error protection features including approximately 9.6 kilobits / second. The data rate of an audio CD (stereo) is about 1500 kilobits / second. This means that an audio CD cannot be in “real time”

Redundancy Reduction

As redundant are colloquially information or data that can be derived on the basis of already delivered / transferred information by deduction. It is therefore not necessary to separate these so-called redundant data, addition or transfer of all. Redundancy describes the degree of predictability of parts of a message, to make it a little less mathematical term.

The redundancy in a message / information can be determined with mathematical accuracy. It is still not of any technical or mathematical effort possible to remove a large amount of redundancy from a message when the message contains. Unless one deliberately distorted the original message or deliberately takes error in the reconstructed message in purchasing.

“The basic principle of the removal of redundancy is used wherever Use, where it comes, unadulterated information on over-wear. Examples include: encrypted data, text, or Account information. Where it is obvious that it is not may be reproduced falsified.”

The avoidance of redundancy is carried out with the methods used for lossless data compression. All in all, it is in the lossless data compression therefore, to replace the message to be transmitted by a shorter but equivalent message, and then to transfer them to reconstruct on the side of the receiver without error. You will see throughout the book that the options for encoding are very diverse. A distinction is statistical, dictionary-based and combined approaches. You will learn how these different ideas and are open to the possibilities of combinations.

Irrelevancy

Irrelevant refers to information or data, which cannot be perceived by the observer or the receiver or the accuracy, is not sufficiently visible. As a bad example, one could choose a red / green blind man who can notoriously difficult to distinguish between red and green. By the absence of the receiver it would be sufficient distinctness example, optionally to transmit the red and the green component. That means you decide to use physiological principles, conditions and models to whether information is a transfer value or not.

In the irrelevance it is possible by means of technical or mathematical models, to separate relevant information from irrelevant information. Usually lead to complex models, methods of measurement or empirical values are found, the basis of which the decision can be made whether the information is relevant or irrelevant. In particular, objective and subjective criteria play a role.

“The basic principle of irrelevance reduction is used in applications where it does not ensure the accuracy of the reproduction of information goes, but where even mild, moderate or severe distortions of the original Information is acceptable. Examples include audio, video, or Image data.”

Moreover, it is possible not only not sufficient to suppress perceptible information, but they bear also perceptible error in purchase, so as to adjust the information to be transmitted to the type of coding. The advantage of adaptation to the type of coding is to decide that the encoder can result which modification during encoding to a better compression performance. The encoder produces the modification called compression artifacts, which make it possible to the encoder to obtain a predetermined compression rate, or to fall below. The method by which this type of encoding can be accomplished are described in the Lossy data compression treated.

Combination of both

After the introduction already indicated that it is in the data compression is a transformation or mapping of the data, one can get the idea, various transformations applied successively. In a redundancy reduction it does not matter how often a transformation takes place, or how complex transformation rules, it is not possible to achieve a higher coding gain, as permitted by the so-called redundancy. What can be done in principle, is the process by which the irrelevance of combining redundancy reduction. It is important to adhere to the following sequence:

1. In the first steps should always be removed from the irrelevance data to be encoded.
2. This, first relevant and irrelevant information is separated or converted into an appropriate representation.
3. The following steps then try the remaining redundant portions of the message to be encoded to remove.

This procedure is wherever possible and appropriate, where changes to the information to be encoded are acceptable. The same conditions as in the methods used to irrelevance reduction. There’s basically no method to remove only irrelevant, but such methods are always combined with a method for redundancy reduction. The combined methods are covered in lossy compression.

To be closer to deal with the process for the irrelevance it is best if you have dealt with the chapter for lossless coding because only the final lossless coding makes a lossy coding only really efficient.

The bank reconciliation is therefore to associate transactions already recorded in the company and the bank to show paperwork isolated, that is to say only recorded by the bank or institution. This process can be facilitated by software tools specialized FRP.

Bank Reconciliation Issues

This helps detect errors during recording as an oversight or errors.

By eliminating the differences between the observed and accounting for approaching reality, it is possible to detect:

• omissions of records
• bank charges, bank charges, we find the account statement,
• Errors accounting records
• Offsets some known processes by establishing first and after that saves the bank or vice versa.
• (Given that the accounting transaction may appear next month on the bank statement)

Documents Necessary for the Completion of the Reconciliation

Collect the following documents:

• An account statement received from the bank (called the bank statement)
• The bank account (extract from ledger account)
• The last bank reconciliation.

Realization of the Score and Approximation

Phase 1) Achieve a score (lettering) transactions between the bank account ledger and bank statement (and former bank reconciliation). Not letterer deferrals, sales start and end.

Phase 2) Indicate in two reconciliation tables “end balance” bank statement and ledger account. The ending balance is the balance at the end of the document. It must follow the principle for this phase, the same table, same column.

Step 3) Enter the amounts of non-literate two documents in the two tables of reconciliation following the principle: table opposite, opposite column. Make subtotals whose differences must be equal.

Phase 4) Scripture regularization of non-literate statement amounts.

This document gives the net result is to say that the company has earned (profit) or loss (loss) during the period, which included the balance.

The income statement includes, in its developed version, the intermediate balances describing how the result is constructed. Can be determined as:

The commercial margin: total sales – total purchases.

➜ this calculation is useful for companies that sell hardware without transformation.

The value added: gross margin – Other purchases and external services not stored.

➜ Expresses the company’s ability to generate earnings from its core business.

The operating result: total sales – total purchases and external services (renting, insurance, transport, etc.)..

➜ This indicator expresses the company’s ability to generate earnings from services performed by third parties.

The financial result is obtained as the difference between income and expenses. The exceptional result is obtained as the difference between income and expenses outstanding.

The final balance, said net income is the sum of the previous three intermediate results. It appears at once:

• in the income statement, of course,
• and, in return , the balance sheet of the company, in equity, preceded by a negative sign in the case of deficit (the negative sign is sometimes replaced by parentheses for reporting issues).

Using:

The income statement is a part, such as the balance sheet and various appendices accounting, accounting statements that are intended for financial people

• both internal to the company: management, staff
• external to it, but having a situation of beneficiaries: tax authorities , shareholders, bankers, suppliers, etc..

So that they can judge the performance and profitability of the company.

Hardware is the physical part of the computer: The case with the processor, hard drive and DVD drive, the screen, the printer. You can touch the components; they have a weight and can be installed with a screwdriver. Hardware is broken only rarely, and if so: there is warranty on hardware. You have a right to free from defects (if there are any) and return.

Software, in contrast is the non-material part of the PC, the operating system and programs, such as the writing program and the Internet Explorer. Software is installed using the keyboard and mouse. Software breaks down often. But there has never been a software developer, who would have given any guarantee on the accuracy of its software. Worse: There is no error-free software. The situation is aggravated by the fact that the users make mistakes. Everyone clicks sometimes be wrong. Statistically, almost all computer problems are caused by software errors, and operator error.

The first computers were built in the forties. Graphical user interfaces are there since the fifties. The home computer Altair 8800 1974 reached the mass market. In 1981, IBM introduced the “Personal Computer” on the market, and its plan is still plugged into any PC. The foundations were laid for today’s PC already a long time ago. The advertising and the journals give us the impression that it would be introduced permanently revolutionary innovations. Sometimes even technological regression is declared as progress. Of course, you know that advertising has the purpose to inform you, but you animate for purchase (“That’s new! The buy be sure!”), and journals must contrast with lurid articles from the competition, and of any “novelty” and every rumor write first.

The Real Innovation

In 1948, the transistor was invented and founded the Norbert Wiener cybernetics. The circuits and procedures for CPU, RAM, ROM work, floppy and hard disks were in the 60s already as “proven technology”. In 1960, the inkjet printer was invented in 1969 and 1971 of the disk laser printer. Since everything is integrated into smaller, faster and higher, but not fundamentally different.

1974 developed Intel the 8-bit processor i8080. In 1978 developed successor 16-bit processor i8086 was “compatible” design so that the programs of his predecessor after an automatic recoding were run on the i8086. Intel in 1978 against IBM obliged every new processor develop “backward compatible” – and keeps itself in the fact, as well as AMD and other processor manufacturers. “Backwards compatibility” means that old programs run on the following processors, even 30 year old programs!

In 1964, the mouse was invented in order to make working with computers easier to use. In 1973, the “Xerox Alto” a “graphical user interface” developed (English Graphical User Interface, abbreviated GUI). With the “Amiga” in 1985, it reached the mass market. In 1990, Microsoft. Initial success with a graphical add-on for DOS, which was given the name “Windows” Since then, everyone can choose whether he wants to type cryptic commands or the computer rather operated with the mouse.

In recent years, parallel processing reached the mass market. Since 2002 there is a “Hyper-Threading ‘procedure: If during the execution of a program part, a waiting time occurs (e.g., because the data has not yet arrived from memory) is changed to a different part of the program. 2006, the first “Dual Core” CPUs have been sold that contain two processing plants in the CPU. What is new is that, however. Already the British “Colossus”, which was used in 1943 for deciphering secret codes, was a parallel computer. Today’s supercomputers have thousands of processors.

Also in the field of software, many of the foundations were laid decades ago:

1. In 1974, the operating system CP / M, and in 1981 developed the mind ajar appeared MS-DOS 1.0 was the first operating system from Microsoft. Every few years, there was an enhanced version of MS-DOS; the last one had the 6.22 version number. For those who do not know DOS: This operating system does not use a mouse running in plain text mode. All commands have to type on the keyboard. Example of a DOS command: xcopy c: text * a doc: * doc / d / s / e / y. These command line options are used by many professionals, because some of these commands are much more effective than the click of a mouse, and some of the “classic” commands can be a last resort, if Windows does not work anymore.
2. With each new version of an operating system respect the developers that in addition to all improvements and all the old commands still work. This allows you to use after the transition to a more modern operating system your older, cherished programs and, of course, also use your information. This principle is called friendly (downward) compatibility. This way I can still use most of the commands that I learned in the 80s.
3. Windows 2000, XP, Vista and Windows 7 come from the start without DOS. The classic DOS commands are not disappeared. All versions of Windows have a window for DOS commands, called the command prompt. Over the years, the DOS commands have been further developed. Because many new commands have been added, one no longer speaks of DOS commands, but from command line switches. The command line is so extensive those modern Windows operating systems for server install complete with command lines to configure and use leave without even a single time to use the mouse.
4. Not only is there almost always used the Windows operating system for personal computers, but also a variety of alternative operating systems, of which Linux is the best known. The roots of these operating systems usually reach even further back than that of Windows.
5. E-mail is not as new as you might think. The first experiments were carried out in 1971. In 1979, Eric Allman, the program “Deliver Mail” finished, which was renamed in 1981 “sends mail”. The vast majority of e-mail server uses this program is still in a more advanced version of an “electronic post office.”

What is that – a number system?

A numbering system is used numbers – especially large numbers – simply and clearly display. Moreover, it should be simple to count the numbers.

With the growth of the first cities and civilizations came the need to deal with large numbers. Write down on a beer mat with a few strokes of the number of ordered beers, is clear. Noting with 300 strokes, that a resident has paid his taxes with 300 jars of wine is very confusing. Therefore, the first number systems have been invented: the Sumerian, Egyptian and later the Roman numeral system. The basic idea: For large quantities of one’s group symbols are introduced. The Romans used the letter “I” for one. Ten lines were replaced with an “X”; “C” stands for one hundred and “M” for a thousand. Additionally, there are six figures: “V” for five, “L” for 50 and “D” for 500 so you could replace the 300 lines of “CCC”. “MCCXIII” thus means the 1213th the number 132 can be written as CXXXII, IIXXXC, XCXIIX or XXXIIC. The order of the numbers does not really matter, only the total counts. Therefore, such payment systems are called “Addition systems”.

Any order of the digits causes, however, that a number are many different spellings. This is confusing. Therefore, the Romans had a rule to write the larger number from the smaller.

For the Roman numerals there is another, somewhat odd special to avoid the writing of four equal consecutive characters: in front of a larger point stands a smaller, the small of the great deducted. The numbers are shorter. One writes for the number 49, for example, “XLIX” ((50 minus 10) plus (10 minus 1)) instead of “XXXXVIIII”.

The addition and subtraction of Roman numerals is not easy, considering our current knowledge and habits. To multiply, divide, or to potentiate even be a nightmare. This is probably a major reason why the Romans are no discoveries in the fields of mathematics, physics and astronomy known.

The Indians invented the decimal system and the Arabs have it in the 13th Century to Europe. By the arithmetic books of Adam Ries it became known in Germany. This system greatly simplified the calculations.

Explain the specificities of the decimal system are superior to Roman numerals?

• The decimal system is a priority system with ten digits. All figures, small or large as desired, can with ten digits (the digits 0 through 9) are formed. Ten decimal digits =.
• The decimal system is a “point’s value system “: The” value “of a digit depends on where it is a number. When a number of advances in the last position of the penultimate digit of a number (for example, if you right appends a zero), it is ten times more “value”. In the number “333″ is the number 3 three times before, where it has three different meanings: Three hundred thirty and three.
• For calculating with large numbers, there are “relatively simple” rules. Whether I expect double-digit or 20-digit numbers, the rules are the same.

We use the decimal system, because we count things on ten fingers. People would have a less movable thumb; we would possibly hold the octal number for the natural system in the world. If we could have easily movable toes and would walk barefoot, perhaps the Twenties number system would be optimal. The Mayans and the Aztecs had it, and some isolated indigenous peoples are using it too.

For computers is also a priority system is used in which there are only two digits zero and one. This “binary system”, also called “dual system”, was invented by Leibniz. The name comes from the Latin: bina = pairs, duo = two. Thus z, B, the binary number “110″ in the decimal system 6 the value

As is expected in a place value system? Whether it is the rules for addition, multiplication, division and other acts, all known calculation rules apply to all place-value number systems alike.

Although the calculation of probabilities of random issues has long existed, mathematical formalization is only recent. It dates from the beginning of the 20^th century with the Kolmogorov axioms. Objects such as events, the probability measures the probability spaces or random variables are central to the theory. They allow translating the abstract behavior or measured quantities that may be assumed random. Depending on the number of possible values ​​for the random phenomenon studied the theory of probabilities is called discrete or continuous. In the discrete case, that is to say, for at most countable number of possible states, probability theory is similar to the theory of counting, whereas in the continuous case, the theory of integration and measurement theory provide the necessary tools.

Objects and probabilistic results are needed to support statistical; it is the case for example of Bayes theorem, evaluation of quantiles or the central limit theorem and the normal distribution. This model also allows the chance to solve several probabilistic paradoxes.

Whether discrete or continuous, the stochastic calculus is the study of random phenomena that depend on time. The notion of stochastic integral and stochastic differential equation is part of this branch of probability theory. These random processes are used to make links with several more applied areas such as financial mathematics, the statistical mechanics, the image processing, etc…

Before the study of probability is considered a science, observation of random natural events led philosophers and scientists think about the notion of links between events, causes and consequences, and the laws of nature. Gambling, weather patterns or trajectories of stars have made ​​some of the areas studied. The explanations are then bound to destiny, to anger celeste or a divine presence.

Definition

At different times or areas of application, probability theory can take different names: the theory of mathematical probability, the calculation of probabilities seven , or more simply the probability although it should not be confused with the probability an event that is assessing its probable nature or one probability is a law (or extent) of probability.

It was the 113th Space Shuttle mission – the only one in 2003 – and the 28th Flight of the space shuttle Columbia.

Team

• Rick Husband (second space flight), commander
• William McCool (first space flight), Pilot
• Michael Anderson (second space flight), Mission Specialist
• Kalpana Chawla (second space flight), Mission Specialist
• David Brown (1 room), Mission Specialist
• Laurel Clark (first space flight), Mission Specialist
• Ilan Ramon (the first space flight), Payload Specialist ( Israel )

Mission overview

About 80 scientific experiments were carried out on this mission. The cargo compartment of the Columbia housed next to the space lab Spacehab RDM (Research Double Module) and the experiment package FREESTAR, which was placed on a bridge structure.

On STS-107 flew with Ilan Ramon, an Israeli astronaut into space for the first time.

Preparations

This flight was the last shuttle mission, which was dedicated to scientific research, before the International Space Station should take over this activity. Due to delays in the shuttle program, technical problems and changes in the payload was the Columbia flight postponed again: was selected as the Israeli astronaut Ilan Ramon, 1997, NASA posted the manifesto launch for May 2000. With the announcement of the commander and pilot in December 2000 STS-107 had already slipped back a year after (July 2001).

The order and the cargo have been several changes. There were considerations in the NASA Headquarters to allow the conduct of a flight crew, which consisted solely of women. Payload as a time of Earth observation satellite was Triana provided. This after the lookout Rodrigo de Triana, on the Columbus’ first voyage discovered America in 1492, was named Trabant at the suggestion of former U.S. Vice President Al Gore has been developed until the 2001 Congress stopped the agent.

The space shuttle Columbia was on 12 March 2002 from its final mission STS-109, a maintenance flight to the Hubble Space Telescope returned. A few weeks later, this date was the 11th July, eight days postponed to allow more time for the preparations.

On 24 June 2002 for the 19th July planned launch of STS-107 again to “a few weeks” published after the fuel lines of two orbiters between two and seven millimeters long hairline cracks were discovered. During routine inspections, technicians had on 17 June at the Atlantis found the first crack, and then also on the Discovery, which has just been upgraded. It was then for the Columbia and only a few days earlier of STS-111 returned Endeavour arranged investigations. NASA also imposed grounding of the shuttle fleet until the cause of the cracking was found.

In early July in a line of Columbia three cracks were found, a few days later, two at the Endeavour. A total of eleven hairline cracks were detected in all the space shuttles. At first it was unclear how it arose and whether they were dangerous.

On 12 July said Ron Dittemore, the manager of the shuttle program, that there will be mid-September 2002, no further starts. Perhaps the problem of hairline cracks existed since the first launch in April 1981, and we’ve only now discovered. Pending resolution of all other issues would be suspended, or at least as long as the engineers could make up that the cracks were not larger and posed no danger. Two weeks later, on 26 July, announced Dittemore that it is enough to weld all eleven found cracks. Engineers had determined after detailed analysis that metal fatigue caused by the high thermal and mechanical loads on startup, the cause would be sufficient and should be repaired.

Mission History

Because of after the terrorist attacks of 11 September 2001 adopted safety regulations were the exact date of the launch on 16 January 2003 not named. Only a four-hour window (15:00 to 19:00 UTC) was announced, would take place within which the start. This concealment measures had other stations of the preparations of which would have been the moment of the launch can calculate how the arrival of the team in Florida, the start of the countdown, etc. It was not until 24 hours before the planned start date was the date notified by 15:39 UTC.

There was also a heightened state of alert the authorities responsible for the security agencies. Around the Kennedy Space Center based military units position – snipers were stationed, and military helicopters patrolled interceptor, mobile rocket launchers to advanced and restricted zones were extended. NASA stressed that these measures are part of the new security concept and had nothing to do with the fact that the first Israeli astronaut belong to the shuttle crew.

Until just before the start it was not clear whether the mission would experience a renewed postponement. In December 2002, technicians had diagnosed to a ball joint of the Discovery problems which provides within the large fuel lines for their flexibility. A six-centimeter metal ball was on the surface cracks. NASA engineers debated whether standing on the ramp Columbia should be reduced because a site inspection was not possible. On the eve of the launch, it was decided that a defective ball joint may not pose a threat to the Columbia.

On 16 January 2003, the Columbia left on time at 15:39:00 UTC ideal weather to the launch pad. This followed a countdown was without technical difficulties. Unlike missions that fly to the International Space Station, and only use a short launch window of about five minutes, can you had more time this time. STS-107 was the maximum period of two and a half hours. The launch window was limited by NASA policy that may be the time, the team members strapped on their backs, limited for health reasons on 150 minutes.

A day later, routinely the filming of the launch was spotted. The analysis showed that about 81 seconds after leaving the ramp, a piece of foam insulation from the external tank had come loose and hit the left wing. Serious damage had occurred there before. It was also visible on the high-speed imaging, that the fragment after the impact, leaving a cloud of particles, which was interpreted as its destruction. Therefore, NASA decided to continue the mission normally.

Working in the orbit

The first days were quite on the flight schedules. A few hours after reaching orbit, the astronauts floated into Spacehab module and activated the experiments. On 20 January 2003, the fifth mission day came, for the first time on problems, as the temperature rose in Spacehab because of regulator damage in life-support system. In the morning had the air conditioning of research module will be disconnected after condensation had expired, and 19:15 UTC against a short circuit led to the failure of the replacement system. As a result, it reached the room temperature in the module to a peak of 29 ° C (7 ° C above the normal value). To make the work more bearable for the astronauts and off no experiments have been temporarily routed air from the middle deck in the connecting tunnel. A day later, the temperature had fallen to 24 ° C.

On the twelfth flight day, the 27th January, there was a friendly conversation, as the crew of the shuttle with the International Space Station (ISS) was contacted by radio. The Red team commander Rick Husband had just started his shift, when Ken Bowersox, the head of the sixth crew, reported around 17:30 UTC. It was a satellite radio link, because the two space ships not because of their different orbits met. At the time of the Columbia short conversation about Brazil and the ISS was over the Ukraine. In addition to greetings and good wishes to Kalpana Chawla inquired of ISS Flight Engineer Don Pettit as his twin sons go.

A day later, was 17 Anniversary of the Challenger disaster. Just one minute after launch on 28 January 1986 was the explosion of the space shuttle and had seized the seven-member crew to their deaths. Both on Earth and in space commemorated the deaths of the Challenger and the three at a soil test astronauts who died of Apollo.

Three days before the scheduled landing payload commander Mike Anderson drew on 14 Flugtag, 29 January, a positive balance: The scientific harvest was a great success and many experiments have exceeded expectations by far. And Ilan Ramon, Israel’s first astronaut, said during the traditional press conference that he would like his country was so quiet and peaceful, as it appeared from space.

On 31 January, the astronauts were prepared for landing to the next day. The Spacehab was disabled; the experiments and samples stored and made ​​other preparations for the return. In Control flight director LeRoy Cain had a press conference pointed out that the analysis of the footage had revealed the launch of Columbia, that would have solved a piece of foam insulation from the external tank and hit the left wing. Possibly doing some of the heat shield tiles was damaged. The engineers were therefore not concerned and the landing would be carried out as planned. What should be shown later, this was an error of judgment?

The Catastrophe

The Columbia orbited the Earth at a height from 272 to 289 kilometers, as on 1 February at 13:15 UTC for half minutes, the braking engines were fired. The weather conditions for a landing in Florida were, apart from local fields and low clouds, fog, good. At 14:15:50 UTC, the Space Shuttle from Kennedy Space Center put on runway 33 with the main landing gear.

Over the Pacific, the orbiter was at 13:44 UTC at 122 km altitude in the denser layers of the atmosphere. Seven minutes later, reached the Columbia north of San Francisco, the West Coast of the United States. The ferry broke 16 minutes before the scheduled landing at an altitude of 63.1 kilometers over Texas apart. Upon entering the denser atmosphere had the telemetry indications of irregularities frequently.

The later reconstruction of the accident revealed at 13:48 UTC that the first indications of an unusual behavior when the load sensors in the left wing leading edge gave anomalous values. 20 seconds later, the temperature soared to at this point. Hot gases having a temperature of about 1800 ° C were penetrated through the wing leading edge in the wing and destroying their structure. The fallen during the start fragment of the tank insulation had made ​​of carbon fiber reinforced carbon (reinforced carbon-carbon short: RCC) wing leading edge damaged existing.

At 13:59 UTC was held the last radio contact with the Columbia. Shortly before the Columbia was from New Mexico flew over the border coming to Texas. Jeff Kling, the engineer responsible for the mechanics of the space shuttle in flight control, informed flight director Cain, he of the two tires of the left main landing gear do not get any more pressure values. Then tore at 13:59:23 UTC for the first time from the telemetry – the controllers in Houston received any data. A second later gave compound spokesman Charles Hobaugh by to shuttle commander Rick Husband, that you watch the tire pressure. This acknowledged with a “Roger”, as the middle of the next word broke off the connection at 13:59:32 UTC. The last data fragments Houston reached half a minute later, before the final demolition and contact the Columbia broke apart over Texas. Some parts of the Columbia burned up; others went down as debris rains over the southern United States.

The Columbia was the second orbiter, the NASA lost. The space shuttle Challenger was 17 years earlier, on 28 January 1986, at the start of the mission STS-51-L accident.

Initially it was not clear what had happened. The first official comments of NASA told only that they had lost contact with the space shuttle around 14:00 UTC. Even if a crash was not explicitly stated, we pointed out at the same time, debris not to touch and localities to report to the authorities.

Investigation of the crash

A day after the accident, called NASA chief Sean O’Keefe establish an independent commission of inquiry. The Commission called CAIB (Columbia Accident Investigation Board) should clarify how it had come to the accident. As Chairman U.S. Navy Admiral Harold W. Gehman was appointed three years ago retired from active service and the last Supreme Allied Commander, Atlantic, NATO was.

Initially circulated within NASA different theories of what may have caused the disaster – a defect of heat protection was just one of them: Autopilot, who at the time headed the Space Shuttle, could have failed. Another possibility was that it was due to the age of Columbia come to material fatigue and structural integrity was compromised. Even a fire caused by electrical fire, a collision with space debris or a terrorist attack has been considered.

The first indications pointed out that the cause is to be sought at the wheel well because the rapid development of heat seemed to emanate from there. Ron Dittemore, the manager of the shuttle program, said the first two days after the accident that the thermal protection system could have been damaged elsewhere.

To find out the cause of the crash, the wreckage of the Columbia were assembled in a hangar in Cape Canaveral again. In addition, the images of the foam piece with the computer were reworked.

Almost seven months after the crash of the space shuttle closed the inquiry the Commission investigation, which cost over $ 20 million from, and published on 26 its final report in August 2003. The report was given as the cause of the startup fallen piece of insulating foam of the external tank. It had made ​​a hole in the front edge of the left wing during re-entry through which extremely hot plasma had occurred in the space shuttle had let fall apart.

Hole In A Model Of The RCC Panel

Subsequent experiments confirmed this theory: After being with nitrogen cannon fired at the correct angle, a 1 kg heavy piece of insulating material with about 800 km / h on original RCC panels, it was found that the hole has a diameter of at least 25 cm. During re-entry through the defect site of the RCC panel # 8 penetrated in the front edge of the left wing of hot plasma that spread within the wing structure. This is the wing structure weakened sustainably destroyed several sensors and parts of the hydraulic system, so that it failed. This led to loss of control of the position control, the aerodynamic stability of the Columbia was lost, and it broke under the enormous aerodynamic forces.

Almost half of the report also criticized mechanical error and the NASA management. Thus, the space agency has been blamed in the report, to have evaluated several warnings from engineers about the possible extent of the damage suffered wrong at the start. The Commission also revealed serious shortcomings in the communication between various NASA locations. Example, it was criticized that the PowerPoint presentations about possible problems with a shuttle flight important points were not disclosed. The reason gave some engineers that “it would not have looked good visually, presenting these issues on multiple screens.” Reason for the multi-page collection was said to be a restriction in the PowerPoint software.

According to this report, the space shuttle program came publicly deprecated and vulnerable into disrepute. On 14 January 2004 U.S. President was George W. Bush announced a new space program. After that, the shuttle program will continue to be operated only by the year 2011, to build the International Space Station completed. This was also associated with reductions for the shuttles.