И.С. Гудилина, Л.Б. Саратовская, Л.Ф. Спиридонова - English Reader in Computer Science, страница 11

But investigations of alternate message handling protocols are based on mathematical models of the message traffic. Good models assure that a new protocol will perform as well in practice as queuing theory predicts; bad models can lead a protocol developer to make performance promises that can't be fulfilled.

When traffic is light, propagation time dominates, and message packets are best sent in the area of mathematics known as graph theory. (R. E. Bellman, L. R. Ford, and E. W. Dijkstra are among the mathematicians who first developed shortest path algorithms in the late 1950s.) When traffic increases, the network router needs to find all paths between the sender and receiver, a task that can be handled using modem graph search techniques developed in the 1970s by R. E. Tarjan, J. E. Hopcroft and others. Knowing that both the shortest path and all available paths can be found, many network routing protocols then focus on different criteria for making the commuter's choice between the short but possibly congested road and the longer but freely flowing route.

Mathematics and the Internet

Mathematics is the language of Internet operation, from the binary numbers that describe texts and images to the complex data structures of search engines for the World Wide Web. Adroit combinations of old and new ideas from fields like number theory have enabled such key Internet technologies as data encryption for secure financial transactions. At the same time, the Internet has given birth to world-wide collaborations among mathematics teachers and researchers, collaborations that are advancing both education from kindergarten through university and our understanding of some of the most difficult problems of pure and applied mathematics.

NOTES:

1. Wavelets are a mathematical tool that has been developed in the last decade by A. Grossman, Stephan Mallet, Ingrid Daubechies and others to circumvent the limitations of classic Fourier analysis, which is restricted to analyzing fundamental frequencies.

I. Answer the following questions:

1. What language do computers use?

2. What kind of messages can be transmitted through the Internet?

3. What form are Internet messages transmitted in?

4. What are the two basic problems of securing Internet massages?

5. How can errors be detected in the Internet?

6. What is a financial transaction?

7. How is financial security provided in computer communications?

8. Can anyone crack a RSA coded message?

9. How can "trains" lengths affect Internet traffic?

10. What are the main principles of data searching?

11. What mathematical theory can be used to describe the behavior of message traffic in the Internet?

12. What applications of prime numbers theory in the Internet do you know?

II. Write a summary in English.

Stage A

1. Look through the text (scheming reading).

2. Divide it into introduction, principle part, and conclusion.

3. Find and write down the main idea(s) of the text.

Stage В

1. Read the text again but now attentively (close reading).

2. Give detailed answers to the questions.

3. Write the items of the plan.

Stage С

1. Write out kernel sentences to illustrate the items of the plan.

2. Join kernel sentences together; use connective words if necessary.

3. Re-read your summary and make sure that the sentences are presented in a logical order. Make any changes that you think are necessary.

III. Read the text. Agree or disagree with what is told in the text. Write about your attitude to the problem. Give arguments in favour of your point of view

Computer network called Internet is worldwide known. Many people, more than 30 million, are using this network to get diverse information.

The main part of the information on Internet is presented as Web pages. Hence, making Web pages today is very actual. Internet is not only based on software, but on hardware as well. Each of these components supplements each other.

Fundamentally, Web and all its contents is software. Thus, technical disciplines such as information science, software engineering, and usability engineering can and should inform questions of Web design and development.

Making a Web page is not so hard, but the right equipment helps. Having a home page is going to be as common as having a fax number- One of the main concerns that may scare away from Web publishing is the notion that a pricey 200-megahertz Pentium system is necessary. But equipment requirements really depend on the results. There are several ways to use the computer for Web publishing. The first is creating the Web pages, HTML (hypertext markup language) is a text-based publishing language that brings Web pages to life. Using HTML, one can probably produce prolific numbers of Web pages on an old 286 system with DOS- based word-processing software. But although that old 286 may be fine for whipping out HTML pages, one may run into a problem when viewing the fruits of your labor. To view a Web page, a Web browser is needed. Both of the major ones, Netscape Navigator and Microsoft Internet Explorer, offer versions that cover operating systems back to Windows 3.1, but no further. Web pages as files are kept on a special computer called a Web server. This server connects directly to the Internet via one or more high-speed telephone lines, and runs specific software that enables people around the world to browse Web pages.

The Web of today provides no clue about the needs and motives of individual readers. At least for the time being, and certainly for the next year or two, the Web provides its users with a fragile veil of limited anonymity. Thus, it's fundamentally impossible to predict or ascertain the motivations, goals, or priorities behind the individual requests for a particular Web page.

In the absence of reliable knowledge about individual users and their needs, site designers have to rely on the "best guess" available about the needs of Web users as a group. In other words, conscientious designers will seek to understand what brings most users to most Web sites. They will attempt to address the needs of that majority as an optimal means of providing value to the largest possible readership. But what do people want? Nearly everyone wants information. The single most common use of Web is to find information. Nearly 90% of Web users report that they use Web as an information source.

Unit 5

Collaboratories: Doing Science on the Internet

The success of many complex scientific investigations hinges on bringing the capabilities of diverse individuals from multiple institutions together with state-of-the-art instrumentation.

We are all aware of the tremendous impact computers have had on science and engineering in the past 50 years, but this impact in the near future may be far greater- A 1996, National Research Council study suggested that the fusion of computers and electronic communications has the potential to dramatically enhance the output and productivity of US researchers. A major step toward realizing that potential can come from combining the interests of the scientific community at large with those of the computer science and engineering community to create integrated, tool-oriented computing and communications systems to support scientific collaboration. Such systems can be called "collaboratories."

The term collaboratory was coined by William Wulf while he worked for the US National Science Foundation. Wulf merged the words collaboration and laboratory and denned a collaboratory as a center without walls, in which the nation's researchers can perform their research without regard to geographical location — interacting with colleagues, accessing instrumentation, sharing data and computational resource, and accessing information in digital libraries.

To what degree can we realize this potential? Computer scientists working with domain specialists have made progress on several fronts to create and integrate the tools required for Internet-based scientific collaboration. However, both technical and sociological challenges remain.

Collaboration is at the heart of science, with a tradition spanning centuries. However, while science has benefited greatly from the computing revolution of the last five decades, technology's impact on the collaborative process itself has been insignificant when compared to our expectations for the near future.

Scientific collaborations currently rely heavily on face-to-face interactions, group meetings, individual action, and hands-on experimentation. Group size varies widely, from as few as three people in molecular chemistry to 300 in high-energy physics.

The tools of computer-supported cooperative work are now being applied to such collaborations. Through immersive electronic interaction, team members distributed across a widespread area can collaborate, using the newest instruments and computing resources. A new paradigm for intimate collaboration among scientists is thus emerging that will accelerate the development and dissemination of basic knowledge, optimize the use of research instruments, and minimize the time between discovery and application.

A collaboratory facilitates scientific interaction within a team by creating a new, artificial environment in which individuals can interact. This new place must be socially acceptable to the people who participate and improve their ability to work. Many computing tools must be brought together and integrated to allow seamless interaction. Some of these tools are already in wide use, such as electronic mail and the World Wide Web, while others, like telepresence — the immersive electronic simulation of "being there" — are still being created by researchers.

COLLABORATORY PROTOTYPES

To facilitate scientific work, collaboratory systems must support the sharing of secure data, analysis, instruments, and interaction spaces. Several systems incorporate these basic components.

An advanced example of data-driven collaboration is the Worm Community System, one of the original collaboratory projects sponsored by the NSF in 1990. This system supports researchers studying the nematode C. elegans, a harmless, soil-residing worm of little human significance. The Worm Community System provides a repository of data about the nematode, ranging from the genome to behavior level, and ties this data to the literature. Everything known about C. elegans and everyone contributing to this knowledge is accessible through the system. These capabilities elevate the Worm Community System from a simple tool for sharing data to an electronic forum.

Providing access to scientific instruments from distant locations is another common locus of collaboratories. Early collaboratories focused on the sharing of large, expensive instruments such as astronomical telescopes, particle accelerators, oceanographic instruments, atmospheric observatories, and space research applications. The Upper Atmospheric Research Collaboratory, another NSF-funded project, is an example. UARC provides six institutions access to instruments in Greenland for solar wind observation. (For more information, see http://www.si.umich.edu/UARC/HomePage.html), UARC collaborators exchange and archive multimedia information from the instruments and the measurement analysis. Other collaboratory projects share smaller devices, such as electron microscopes, scanning tunneling microscopes, and nuclear magnetic resonance instruments.

SOCIOLOGY OF COLLABORATION

Facilitating collaboration among a widely distributed scientific community is highly complex. Although a collaboratory is potentially nothing less than the village square of the Information Age, it is a synthetic place requiring social adaptation.

Is such a place socially sustainable? The requirements for a technological system's success seem contrary to the sentiment expressed in the motto for the 1933 Chicago Worlds Fair: "Science finds, industry applies, man conforms." Today we expect technology to adapt to the user. Some people contend that "technology is incompatible with a gentle and humane society," but we believe that technology implemented with an awareness of human needs can facilitate the collaborative process.

Asserting the social acceptability of a synthetic "place" does not make it so, of course. Thus, in addition to purely technical issues, the research agenda for creating collaboratories must address fundamental psychosocial questions as well. Is it possible to electronically create a suitable sense of place that permits and enhances the successful cooperation of dispersed individuals toward common goals? How can we support communication that permits human cooperation even when the evolutionary social mechanisms that depend on proximity are absent? The silent language of body motion and spatial position are central to human communications and social control; can this richness of human interaction be provided? Indeed, which aspects of this richness are critical and which are not?

Collaboratory developers must consider psychosocial issues such as autonomy, trust, sense of place, and attention to ritual. Autonomy, which describes how an organization is governed or regulated, is implemented through informal communications, acquaintances, and associations. Collaboratory developers must embed autonomy into the virtual organization in a considered manner. Trust, which is established among collaborators through shared experience, is implemented over time through informal means such as meeting face to face and working together in the same place. In a collaboratory, trust will people to feel comfortable in their surroundings, provides security so that people can feel creative. If a collaboratory can harness some of the design strategies that have been so successful in physical group settings, it can also create a sense of place and purpose among its dispersed members that will engender an enduring sense of affiliation and cooperation toward its goals. The mechanisms of ritual, which moderate our interpersonal interactions, must find a place in the synthetic surroundings of a collaboratory.

Technology solutions abound, but often fail to find a human problem to solve. Groupware applications, like those for meeting scheduling, group decision support, joint authorship, and distributed management, have had mixed success. The failure of groupware to gain wider acceptance is due to its primitive technology and its insensitivity to social and political issues in the workplace. Groupware applications for a collaboratory will have to be selected and implemented with a clear understanding of the social and political concerns that characterize joint scientific work. Among these are issues of authorship, acknowledgment of contributions, esteem of peers, and recognition by profes­sional role models. Without such characteristics, collaboratory systems will not find acceptance!

COLLABORATION TYPES