Mobile technology standards.

Nowadays, there are three standards for mobile communications: CDMA, GSM and UMTS.

GSM-standard

Customer’s growing demand forced manufacturers to develop a variety of technologies to increase the data rate. Thus, initially, the data transmitted in GSM at a rate of 9.6 kilobits per second. But with the advent of GPRS-technology, subscribers receive a decent alternative to the Dial-Up for mobile Internet access. Almost all Ukrainian operators, the average speed of GPRS-connection is about 40-50 kilobits per second and can vary significantly depending on various conditions.

The next step in the development of high-speed capabilities of GSM has been the development of EDGE technology. Initially it had pinned great hopes up to support streaming video and online TV. But in practice the stated rate was virtually unattainable, thus, EDGE technology was simple, which increases the speed of access to the Internet from a mobile phone compared to GPRS.

UMTS - a new communication standard, which allows you to get in addition to standard services, available in the second-generation networks, and more features such as video calls, online TV and a high-speed Internet access. This technology is recognized as a 3G-standard. UMTS is realized in four frequency bands 850/1700/1900/2100 MHz. However, it is possible that this number may soon be extended. In Ukraine, a UMTS connection is available only at a frequency of 2100 MHz, and is only one provider - Utel, two other operators, "Kyivstar" and Beeline offer their subscribers roaming access to the network.

The rates offered UMTS standard, not long satisfied customers, so was soon developed and implemented HSDPA technology by which data transfer rate has increased nearly 10 times. However, with such a substantial increase in injection rate, the reverse flow was too small. Thus was born the HSUPA technology, which is at the same high injection rate, almost 10 times increased the rate of outgoing data flow. At this point in Ukraine is only implemented HSDPA technology with a peak speed of 3.6 Mb / s technology capabilities allow it to increase to 14 MB / s.

In the 4G technology standards are used LTE and WiMAX.

Many providers often use the 4G term to describe the technologies offered today, sometimes even at the same time distorting reality. However, current 4G implementation mostly relates to the pre-4G, since they do not fully meet the requirements of high-speed 4G - to 1Gbit / s for stationary reception and 100Mbit / s to mobile.

In addition to speed, to qualify as a 4G network, it must satisfy a number of other principles. In short, the network must be extremely spectrally efficient, must dynamically allocate and use their resources to support large numbers of simultaneous users per cell, should offer a high quality of service for next generation multimedia support, and should be based on a switched network all-IP.

LTE -standard LTE Long-Term Evolution (LTE) is regarded by many as the natural successor to the current 3G technologies. This is partly due to the fact that it updates the UMTS network to a significantly higher data transmission rates, as in downloading, and the injection. The specification provides a peak download speed at the level of 100 Mbps / sec, and the injection - to 50Mbit / sec. However, tests in the real world data rate will likely be in the area 5-12 Mbit / sec for downloading and 2-5Mbit / sec per injection.

In general, the LTE standard developed by a consortium 3rd Generation Partnership Project (or 3GPP) as the eighth edition of what has evolved from the GSM family of standards since 1992.

WiMAX - is a broadband wireless standard, which is based on the IEEE 802.16 standard. As the name implies, WiMAX can be considered an extension of the standard Wi-Fi, designed to provide a wide range of devices (from laptops to smartphones) high-speed mobile internet access. The current implementation is based on the WiMAX 802.16e specification, which is a 30-mile range (48,27km) theoretically offers transfer speeds of up to 70Mbit / sec.

Questions:

1. What is Data Center?

2. What are the principles of cloud computing?

3. What is Virtualization Technology?

4. What are the Web-service Cloud?

5. What are the differences between a standard as LTE and WiMAX?

References

2. Lorenzo Cantoni (University of Lugano, Switzerland) James A. Danowski (University of Illinois at Chicago, IL, USA) Communication and Technology, 576 pages.

3. Craig Van Slyke Information Communication Technologies: Concepts, Methodologies, Tools, and Applications (6 Volumes). ISBN13: 9781599049496, 2008, Pages: 4288

4. Utelbaeva A.K.,Utelbaeva A.K. Study guide for lectures on discipline “Computer science”, Shimkent 2008, 84 pages.

Resources:

1. http://www.intuit.ru/studies/courses/673/529/lecture/11914?page=2

Lecture №11. Multimedia technologies.
Purpose: to have an idea about multimedia technologies and 3-D representation of the virtual world and animation.
Plan:
1.Representation text, audio, video and graphical information in a digital format. Basic technologies for compression of information.

2.3-D representations of the virtual world and animation. Instruments of development of multimedia applications.

3.Use of multimedia technologies for planning, descriptions of business processes and their visualization.

1.Representation text, audio, video and graphical information in a digital format. Basic technologies for compression of information.

The modern computer can process numerical, text, graphic, sound and video information. All these types of information in the computer are presented in a binary code, i.e. the two alphabet is used (only two symbols 0 and 1). It is connected with the fact that it is convenient to present information in the form of the sequence of electric impulses: the impulse is absent (0), the impulse is (1). It is accepted to call such coding binary, and the logical sequences of zero and units - computer language. Each figure of a machine binary code bears amount of information equal to one bit.
This conclusion can be drawn, considering figures of the machine alphabet as equiprobable events. At record of binary figure it is possible to realize the choice only of one of two possible states, and, so she bears amount of information of equal 1 bits. Therefore, two figures bear information 2 bits, four categories - 4 bits etc. To define amount of information in bits, it is enough to define the number of figures in a binary machine code.
Depending on in what object the data which are subject to compression are placed distinguish:
1. Compression (archiving) of files: it is used for reduction of the sizes of files by preparation them to transfer by communication channels or to transportation on external carriers of small capacity;

2. Compression (archiving) of folders: it is used as means of reduction of volume of folders before long storage, for example, at backup;

3. Compression (consolidation) of disks: it is used for increase in efficiency of use disk spacious by compression of data in case of record them on the data carrier (as a rule, means of an operating system).
There are many practical algorithms of compression of data, but all of them are based on three theoretical ways of reduction of redundancy of data. The first way consists in change of contents of data, the second - in change of structure of data, and the third - in simultaneous change of both structure, and contents of data. If at compression of data there is a change of their contents, then the method of compression is called irreversible, that is at recovery (extraction) of data from archive there is no complete recovery of information. Such methods often are called compression methods with the regulated losses of information. It is clear, that these methods can be applied only to such types of data for which loss of a part of contents doesn't lead to essential distortion of information. Video and audiodata, and also graphic data belong to such types of data. Compression methods with the regulated losses of information provide considerably big extent of compression, but they can't be applied to text data. Can be examples of formats of compression with losses of information:
• JPEG - for graphic data;

• MPG - for video data;

• MP3 - for audiodata.
If at compression of data there is only a change of structure of data, then the method of compression is called reversible. In this case, from archive it is possible to restore information completely. Examples of formats of compression without loss of information:
• GIF, TIFF - for graphic data;
• AVI - for video data;
• ZIP, ARJ, RAR, CAB, LH - for any types of data.
There are many different practical methods of compression without loss of information which, as a rule, have different efficiency for different types of data and different volumes. However, three theoretical algorithms are the cornerstone of these methods:
• RLE algorithm (Run Length Encoding);

• KWE group algorithms (Key Word Encoding);

• Huffman's algorithm.
RLE algorithm
The idea of detection of the repeating sequences of data and replacement with their simpler structure in which the code of data and coefficient of repetition is specified is the cornerstone of an algorithm of RLE. For example, let such sequence of data is set that is subject to compression:
1 1 1 1 2 2 3 4 4 4
In an algorithm of RLE it is offered to replace it with the following structure: 1 4 2 2 3 1 4 3 where the first of each couple of numbers is a code of data, and the second - repetition coefficient. If for storage of each element of data of the entrance sequence 1 byte is taken away, then all sequence will occupy 10 bytes of memory whereas the output sequence (the compressed option) occupies 8 bytes of memory. The compression coefficient characterizing extent of compression can be calculated on a formula:
where Vx-memory size necessary for storage of the output (resultant) sequence of data, Vn-of the entrance sequence of data.
The value of coefficient of compression is less, the compression method is more effective. It is clear, that the algorithm of RLE will give the best effect of compression with a bigger length of the repeating sequence of data. In case of the example reviewed above if the entrance sequence has such appearance: 1 1 1 1 1 1 3 4 4 4, the coefficient of compression will be equal to 60%. In this regard big efficiency of an algorithm of RLE is reached at compression of graphic data (in particular for monophonic images).
KWE group algorithms
At the heart of a compression algorithm according to keywords the principle of coding of lexical units by groups of bytes of the fixed length is put. The usual word can be an example of a lexical unit. In practice, the repeating sequences of symbols which are coded by a chain of symbols (code) of smaller length get out to a role of lexical units.

There are many implementations of the algorithm, among which the most common are the Lempel-Zіva (LZ algorithm) and a modification of Lempel-Zіva-Welch (LZW algorithm). Glossary This algorithm is a potentially endless list of phrases. The algorithm starts with an almost empty dictionary, which contains only one encoded string, so-called NULL-line. When reading the next data sequence symbol input, it is added to the current line. The process continues as long as the current line matches any entry in the dictionary. But sooner or later, the current line has ceased to fulfill any phrase dictionary. At a time when the current line is the last match with the dictionary plus just read the character of the message, the encoder outputs the code, which consists of an index of coincidence, and it follows the character that broke the strings match. The new phrase, consisting of matching index and the next character after him, added to the dictionary. The next time, if the phrase appears in the message, it can be used to build longer phrases increases the extent that data compression.

LZW algorithm is built around a table phrases, which replaces the character string compressed messages in a fixed-length codes. The table has a so-called property of timing, that is, for each phrase dictionary, consisting of a phrase w and the symbol K, w also entered the phrase in the dictionary. If all parts of the dictionary is completely filled, it stops being adaptive coding (encoding takes place on the basis of existing phrases in the dictionary).
Compression algorithms in this group are most effective for text data of large volumes and are ineffective for small file sizes (due to the need to preserve the dictionary).

Huffman algorithm

The Huffman algorithm based on the idea of coding bit groups. First, the frequency analysis is performed the input data sequence, i.e set the frequency of occurrence of each character occurring in it. Thereafter, the symbols are sorted to reduce occurrence frequency.
The basic idea is this: the more common symbol, the smaller the number of bits is encoded. coding result is stored in the dictionary required for decoding. Here is a simple example that illustrates how the Huffman algorithm.
Suppose we are given a text in which burva 'A' consists of 10 times, the letter 'B' - 8 times, 'c'- 6 times, 'the D' - 5 times, 'E' and 'F' - 4 times. Then one of the possible coding options Huffman given in Table 1.

Symbol	frequency of occurrence	bit code
A
B
C
D
E
F

Table 11- Possible coding options Huffman

see Table 1, the size of the input text before compression is 37 bytes, whereas after compression - 93 bits, which is about 12 bytes (excluding the length of the dictionary). The compression ratio is 32%. Huffman algorithm is universal, it can be used to compress data of any type, but it is not very effective for small file sizes (due to the need to preserve the dictionary).
In practice, software data compression synthesize these three "clean" algorithms because their effectiveness depends on the type and amount of data. Table 2 shows the common compression formats and their corresponding archiver Programs that are used in practice.

Format compression	MS DOS operating system	Windows operating system
Utility program	unzipping program	Utility program	unzipping program
ARJ	Arj.exe	Arj.exe	WinArj.exe	WinArj.exe
RAR	Rar.exe	Unrar.exe	WinRar.exe	WinRar.exe
ZIP	Pkzip.exe	Pkunzip.exe	WinZip.exe	WinZip.exe

Table 12- Compression formats and their corresponding archiver Programs

2. 3-D representations of the virtual world and animation. Instruments of development of multimedia applications.

To create a computer graphics using special software called 3D-editors are. They provide the user with a three-dimensional space, where you can create, move and rotate 3D-objects. Moreover, in modern 3D-editors are there are special tools that make objects move on their own, that is, create animations based on them.
Program 3ds Max, which will be discussed in this course, is such a 3D-editors are. This is one of the most popular applications in the world for the development of three-dimensional graphics, with which created many well-known films, games and commercials.
Three-dimensional graphics - it is something between a computer game and shooting of this film. Window 3D-editors are - a window to the virtual world, which is your set. And only you can decide which movie you shoot, what it will be the scenery and actors.
For the three-dimensional image in the following steps are required on the plane:
• Modeling - the creation of three-dimensional mathematical model of the scene and objects in it;
• Texturing - purpose surfaces bitmap or procedural texture models (also includes the setting of material properties - transparency, reflection, roughness, etc.);
• Lighting - installation and configuration of the light sources;
• animation (in some cases) - giving the movement of the subject;
• Dynamic simulation (in some cases) - Automatic calculation of the interaction of particles, hard / soft bodies, etc. to be modeled by gravity, wind, pushing, etc., as well as with each other..
• Rendering (visualization) - construction of the projection in accordance with the selected physical model;
• Compositing (layout) - finalization of the image;
• conclusion of the resulting image to the output device - a special display or printer.
Multimedia (multimedia) is a set of computer technologies, simultaneously using multiple information environments: graphics, text, video, photography, animation, sound effects, sound, human speech.
Multimedia technology is the combination of modern digital audio, television, visual and virtual communications that allow you to enter, save, process and reproduce textual, audiovisual, graphic, three dimensional and other information.
Technology of creation of multimedia applications
Programs that allow you to combine individual parts into the complete whole-in-one multimedia application that can be divided into three groups:
• specialized program designed for fast training of certain kinds of multimedia applications;
• more tools multimedia;
• programming languages.
The boundary between these three types of programs are gradually eroded, but still quite noticeable. To create presentations and publications, the first group of programs. For the development of other types of multimedia products, the possible second and third options.
More tools media take place between programs, multimedia presentations and programming languages. The division between programs, multimedia presentations and author tools is rather arbitrary. In General, we can say that the first is focused mainly on the transmission of information in one direction (from computer to user), and the second are used to create software products with a high degree of user interaction.
The use of copyrighted media saves time and money, but the efficiency of the program will be lower. Programming is more costly and time-consuming way, but it gives more opportunities for implementing the ideas of the author. More systems offer a programming environment for the scripting language for user-interface design. From real programming languages they are distinguished by their limited capabilities. However, in recent times, there are quite a lot of systems in which the programming, even on the specialized, but the programming language is not mandatory and is complementary to the capabilities of the programs to create the application on the computer screen. Such capabilities and modern programming languages, they added wizards to quickly create applications whose task is building source code in a programming language after the user inputs the basic information on the application appearance.
Thus, the task of choosing the necessary funds to develop multimedia applications is not as simple as it seems at first glance, and versatile solutions, suitable for all occasions.
For the development of a multimedia product requires a set of technical means corresponding to a small multimedia Studio, including:
• a multimedia computer;
• color scanner, better tablet, and is needed for scanning images software;
• recording storage on CD-ROMs;
• video card for digitizing the video (if not, the recording and digitization can be ordered).

3.Use of multimedia technologies for planning, descriptions of business processes and their visualization.

Speaking about modeling business processes, we will use the terminology of several fields of knowledge related to Economics, computer science, complex system modeling. So, before going any further, it is necessary to introduce some basic concepts and definitions. For a start try to understand what actually is — "modeling business processes". A business process is defined as a logically complete the chain of related and recurring activities, in which enterprise resources are used for processing an object (physical or virtual) with the aim of achieving certain measurable outcomes or the creation of products to satisfy internal or external customers. As a customer of the business process could also be another business process. The chain typically includes operations that are performed according to certain business rules. Under business rules, understand the ways of implementation of business functionality within a business process, as well as the characteristics and conditions of execution of the business process. Components of a business process can be performed by people (manual or computer tools or mechanisms) or be fully automated. The procedure and effectiveness of the work of the one who performs the action, determine the overall efficiency of the business process. The task of each enterprise seeking to improve its activities is the construction of these business processes that would be effective and included only do the necessary actions. The term simulation has two main values. First, under the simulation to understand the process of constructing a model as a representative (image) of the original, reflecting the most important features and properties. If the model is already constructed, then modeling is the process of the study (analysis) of operation of the system, or rather its model. The basic purpose of modeling business processes is to describe the real course of the business processes of the company. It is necessary to determine what is the result of the process, by whom and what actions are performed, their order, what is the movement of documents during the execution of the process and how the process is reliable (probability of failure) and how it can be extended/modified in the future. To ensure the transparency of the business processes is important because only in this case, the owner of the business process (employee, Manager business process and responsible for its results and efficiency), business analyst, management and other stakeholders will have a clear idea of how work is organized. Understanding the progress of existing business processes provides an opportunity to judge their effectiveness and quality and the need to develop supporting business it infrastructure. The successful development of application systems supporting the business processes from beginning to end, is possible only when the processes themselves clear details. A model of the business process, is called its formal (graphical, tabular, text, character) description that reflects the existing or proposed activities of the company. The model usually contains the following information about a workflow:

• a set of components process steps — business functions;

• the order of execution of business functions;

• the mechanisms of control within a business process;

• performers each business function;

• incoming documents/information, outgoing documents/information;

• the resources needed to perform each business function;

• documentation/conditions governing the performance of each business function;

• parameters describing the execution of business functions and the overall process.

Questions
1. What is data center?
2. What is the principles of cloud computing?
3. Virtualization technology?
4. What are Web services in the Cloud?
5. What are the differences between a standard such as LTE and WiMAX?
6. What is the purpose of modeling? What types of modeling do you know?
7. What types of computer simulation can be carried out in environments of three-dimensional graphics?
8. What factors influence the degree of data redundancy?
9. What is an archive? What kind of software are called archivers?
Why compression techniques in which there is a change in data content, called irreversible?
10. Give examples of compression formats with loss of information.

References

2. Lorenzo Cantoni (University of Lugano, Switzerland) James A. Danowski (University of Illinois at Chicago, IL, USA) Communication and Technology, 576 pages.

3. Craig Van Slyke Information Communication Technologies: Concepts, Methodologies, Tools, and Applications (6 Volumes). ISBN13: 9781599049496, 2008, Pages: 4288

4. Utelbaeva A.K.,Utelbaeva A.K. Study guide for lectures on discipline “Computer science”, Shimkent 2008, 84 pages.

Resources:

1. http://ru.wikipedia.org/wiki/

2. http://ru.wikipedia.org/wiki/

3. http://www.intuit.ru/studies/courses/673/529/lecture/11914?page=2

<252627 28 29 30 31 >

Дата добавления: 2017-05-18; просмотров: 3889;