Records and information retrieval on the Internet
Basic protocols and Internet search them. Search Tools in WWW. Thematic catalogs. Characteristics of automatic indexes. World Wide Web Worm. Review of Russian search engines. Features search through directories and search engines in a pure form.
|Рубрика||Программирование, компьютеры и кибернетика|
|Размер файла||17,6 K|
Отправить свою хорошую работу в базу знаний просто. Используйте форму, расположенную ниже
Студенты, аспиранты, молодые ученые, использующие базу знаний в своей учебе и работе, будут вам очень благодарны.
Размещено на http://allbest.ru
One of the main differences of the Internet from all rest, that is connected to computers, is that for successful work with it(him), generally speaking, it is not necessary of any books. Internet can serve both directory, and tutorial, and encyclopedia itself. However on the initial stage, as it seems, the advantage(benefit) of the book, distinctly and is accessible of a stating basis, can be rather significant. Such book I also have tried to write. But before you will get acquainted to it(her) more close, let's try to answer on the most important question, which, probably, you already set to yourselves:
The Internet: that it, at last, such more or less scientific definition of the Internet, which the books and clauses on this subject are filled, certainly with, have the value. But the most simple explanation suffices for our purposes while: the Internet is a set of computers connected with each other by channels of communication(connection), plus a set of standard rules, on which they exchange by the information. Thus channels of communication(connection), perhaps, even are less important, than rule of data transfer on them, named in the Internet by the protocols. If even two computers cooperate on one of such protocols is already present Internet.
The invention and the perfection of modems - special devices allowing the computer to send the information on the phone, - has opened doors in the Internet to huge quantity(amount) of the people, at which is not present. Any special network equipment, and there is only personal computer and telephone socket nearby.
Both Internet, and the modems for personal computers exist already rather long. However only at all for a long time - about 1990 - the Internet has typed(collected), at last critical weight of the users and resources necessary for network revolution, occurring on our eyes. The high-speed modems allowing the usual users of personal computers without restrictions to enjoy by all boons of the Internet, have appeared even later. And the system World Wide Web (WWW, or "«World wide web"), invented in 1993 and former firstly only by one of many components of a network, has borrowed(occupied) a leading position and began to define(determine) the person of the Internet literally in last years - two. By and large, the world Internet boom now in the heat - and very much was lucky(carried) to you, that you were not late almost to the beginning of performance.
The Internet is, first of all huge set of computers and programs. Among last you will find not only such, which are able well to decide(solve) your concrete tasks, but also is greater such, whose abilities it will be firstly complex(firstly difficult) even to present to you, probably. The Internet connection gives you a unique opportunity, what imperfect was your computer to have a look per the twenty first century and independently to accustom with such concepts, as « world cyber - social », « virtual money », « information environment(Wednesday) habitation». Item, - word, with all of subjects, about what so love to write now journalists.
However it only part of the answer on a question « that such the Internet ». The Internet today is not only huge quantity(amount) of computers, but also the improbable quantity(amount) of the people, for which network is an essentially new way of dialogue almost not having of analogues in the material world. The man - essence social, and dialogue with itself similar - one of his(its) first needs(requirements). Perhaps, till now still any technical invention (short of the telephone) does not make such revolution in this ancient as the world employment(occupation) - dialogue of the man with the man.
Certainly, what exactly will interest you in the Internet first of all - people or computers, - depends only on you. The ancient metaphor of the book as models of world, perhaps, deserves reconsideration - now on a role of such model computer approaches much better. When the speech goes about millions computers and their users all over the world, connected in a uniform network, the metaphor this already ceases be simply metaphor. That is why by exaggeration will not tell, that, leave in the Internet, you do (make) for yourselves accessible the whole world.
1. Basic protocols in Internet and search in them
Internet contains vast quantity (amount) of the information, on this in it(him) it is difficult to find that that is necessary if not to know where to search. The place of a presence(finding) (or address) each resource defines(determines) it(him) URL. In URL the type of the protocol indicating on what server contains the access is carried out: on WWW (on which specifies recording: http), Gopher, ftp, telnet, or WAIS, it depends on that what type of the information you will transfer. The network protocol - set of the precisely certain rules: how to request, to make out and to send on a network the given version of the information telnet. Millions computers are joined(attached) to a network Internet and many from them have interesting opportunities.
It appears, is quite feasible to reach these computers to look databases, available in them, and programs. The special program telnet allows to transform your computer into the client telnet for a data access and programs in numerous servers telnet. For example researcher regularly can work on several computers, which managers nominate to it(him) a special name and password.
In itself telnet - the communication facility is simple; neither any of the own interface, nor opportunities of search it(he) does not give.
Having contacted the help telnet with the removed machine and having entered in a field of search the entrance name (login) and password (password) you communicate with this machine and programs on further to it(her), and telnet cares only of maintenance of communication(connection) between you.
Certainly, many storehouses of the information, which were originally served by the special programs with access on telnet now it is possible to transfer(translate) on WWW, that not seldom and is done(made). However there were also such which on former give the services only on telnet (especially among the catalogues and information services of libraries).
Standard the link on telnet connection with some site Internet (i.e. URL- the address of this connection) looks so:
telnet: // < the address of the server >
Practically information is stored(kept) in the computer world as files. On this for itself заре Internet the special means for an exchange of files on a network - network protocol FTP (File Transfer Protocol) has appeared.
The quantity(amount) of files accessible on sites of all world on anonymous FTP is measured in astronomical figures and constantly grows. Besides Word Wide Web allows without any alteration existing FTP of archives, to supply with their descriptions of any degree of detail and convenient hypertext interface.
But how to learn(find out) where to address in searches of the necessary file?
The search on a name of a file on all anonymous FTP-sites of the world can be carried out with the help of system Archie. She(it) is developed by the several programmers from university Magellan in Canada and carries out indexation of stations FTP, showing files, accessible in everyone station. Archie informs several millions files taking place in more thousand stations FTP, and gives a surprisingly fast way of search of that place, where it is necessary to be directed for reception of a file, interesting for you. The search in a database of the server Archie is made with the help of keywords, which in this case represent simply names of files or fragments of names.
Now Archie is accessible through WWW. It WWW page with the form in which the keywords and options of search are specified.
Though the name of a file almost always has a certain attitude(relation) to his(its) contents, to use Archie for thematic search of the programs does not cost. This system will be useful, if you really know a name of the necessary file or part of a name. On the other hand if you search for the program, which has the standard reduced name, that is some probability that this reduction will be present and at a name of a file, so it is possible to try to find such file with the help Archie. The results of search represent the list of FTP-sites and complete names of files on these sites. The name of a file serves the link to this file, so the click on a name will allow at once receiving a file from the given site. And domes the address of FTP-archive allocated by a large greasy font will transfer you to the initial catalogue of file system on this archive.
Archie the list into the list into the list into the list into the reception.
URL-address indicating FTP-connection, owes, as a minimum to include a word “ftp” as the left part and address of the site in right:
ftp: // < the address of the server >.
Almost all information resources Internet give an opportunity of automatic search, but only in one of them - in system WAIS (Wide Area Information Server, global information server) - the keyword search, is the basic method of access to the information.
The system WAIS represents the huge distributed(allocated) database, i.e. the separate parts of this database are located on different net points worldwide. The program - client for work with servers WAIS not only is able to communicate with them under the special protocol, but also stores(keeps) the list of all databases WAIS with their addresses and names, and sometimes and with the brief descriptions. There it is possible to find archives of news, every possible catalogues, directories, collections of scientific clauses and abstracts, indexes and much another. Practically any information, for which the database is the convenient form by performances which is interesting enough to a wide audience, can be submitted in WAIS.
The database WAIS is so great, that idle time of recordings - extremely unpromising way of access to the information. Therefore in WAIS the rather complex(difficult) method of keyword search and phrases is applied. The documents received as a result of search, are sorted by the WAIS-server by quantity(amount) of entry in them of keywords and on, as far as is complete in each of them all set of the ordered keywords is submitted. Such system is capable to give good results, is especial if to break process of search at some stages.
The first stage of search usually is the search special in a database under the name “directory-of-servers”, which contains small on volume of the description (abstracts) of all other bases WAIS. Thus it is better to specify not those keywords, which at the end interest you, and those general(common) concepts concerning your field of knowledge.
Having chosen on the first stage of one or several bases, it is possible to begin search actually of documents - that also it is possible to do(make) in some calls, getting acquainted after each search with results and changing the list of keywords, the necessary document will not be found yet. Besides WAIS has one useful property: if at the next stage of search you have found the document, which contents are especially close that you search, it(he) can be added to the list of the relevant documents. In result at the following stage WAIS will find the documents, not only containing a set of your keywords, but also similar on the dictionary structure on those texts, which you have specified as most suitable.
Though Netscape is capable to work with servers WAIS, for this purpose it(he) should know the address of the special proxy for the protocol WAIS, of which your provider can not appear. The special WAIS-clients working including under Windows, not only convenient for interactive search in databases, but also allows to manage services any of the server - intermediary.
URL-address for WAIS looks as:
wais: // < the address of the server > / < the name of base >
Each of the considered till now Internet protocols quite could exist in itself: telnet gives access to the programs, FTP - to files, WAIS - to databases. All these systems were created both developed almost independently from each other and put before itself the concrete purpose - to construct the mechanism of access to one certain kind of resources.
However as Internet of dews also became complicated, it(he) pushed the people to an idea, that the information on a nature is uniform and what not too reasonably to divide her(it) on different “ kinds of resources ” with unlike methods of access. By the end of 80-s' years the idea of a new universal remedy of work with the diverse information was carried in air.
The first system called to embody for life these dreams began Gopher, appeared on light 1991 at the American university of state Minnesota. Fundamental concept incorporated in its(her) basis was structure enclosed each other menu.
Having communicated Gopher- by the client with one of Gopher-servers, you first of all get in the root, main menu of this server. Having oriented in his(its) contents and passing further from one submenu in another, it is possible to engage actually in search of the information. The information in system Gopher is organized strictly hierarchically, “from the general to the particular”. On each step the server sends yours Gopher - client not only contents of the next menu, but also service information on, where there are objects appropriate to items it the menu. The client deduces on the screen only transfer of items, but when you choose one from them, it(he), having verified with the information, available at him(it), or will send on any of Gopher - servers search about distribution of the following of the menu, or will try to establish FTP- or telnet- connection with some site Internet.
Obviously from all information tools Internet Gopher most of all is similar on WWW - both these systems are called to serve the shell with diverse resources. However Gopher is deprived of those rich representational means, which do(make) WWW not only information catalogue, but also new mass media and even by a new genre of art. It is possible to tell, that Gopher is “subset” WWW - that very much simplifies integration itself Gopher as one of kinds of resources in WWW. Practically all that is told about work with Gopher - by the client fairly and for travel on system Gopher with the help of a browser WWW.
URL of one the menu consists of items Gopher - from addresses Gopher- of the server and listed those items of the menu, which will result you in initial item:
gopher: // < the address of the server > / < item of the menu >
In spite of the fact that per the first years of the existence Gopher has won the large popularity, the need in any became ripe more simple and in too time to maximum universal system, in which communication(connection) between resources would be more free and associative. Such system was developed in 1993 and is named World Wide Web (WWW). System WWW to be under construction on concept of a hypertext, or, is exacter than hypermedia. The hypertext is a text of which component are connected with each other and to other texts with the help of the links. The hypermedia is that that will turn out from a hypertext if to replace in his(its) definition a word “text” on “ any kinds of the information ”: the graphic images, video, sound etc.
World Wide Web “world wide web” means literally. Why she(it) so refers to as. As it is clear from the name, she(it) is global. You not always know in what part of light there is a computer, to which you are connected. You can begin to read page Web in Dallas, then to proceed(pass) in Australia, and all this on one pressing of the button of the mouse. WWW is similar to a web. It is a complex(difficult) information network connected hypermedia by communications(connections). WWW allows to not refuse information resources already saved in Internet, other means, accessible with the help, - FTP, telnet and Gopher. It is more than that, the work with these resources through WWW is so convenient, that, say, FTP-clients, former at one time by separate class of the programs, now are used only by few.
And nevertheless main in World Wide Web is not convenience of access to FTP- of archive and Gopher-menu. The majority of servers of system WWW offer the information, which without WWW hardly in general when or would get in a network. Speed of creation and updating, the rich representational opportunities in a combination to ease of access and huge audience have made WWW by new mass media. The start WWW-servers and creation of WWW-pages already has turned of a style to new business - with all that is peculiar to modern business: by a payment for square centimeters of the advertising area.
On the other hand, the fast distribution of system so naturally uniting diverse resources, was promoted not in the last instance by its(her) origin not in недрах of a business concern, and in scientific establishment - European laboratory of physics of particles, which employees did not begin to do(make) of secrets of the development and have not tried at all on it(her) to grow rich.
Fortunately, nature WWW as first of all means of search and organization of the information allows to hope, that this remarkable invention to not turn to the tool of only one commerce and advertising.
The servers and clients WWW communicate among themselves under the special protocol HTTP (Hyper Transfer Protocol, hypertext transfer protocol). URL for WWW looks as:
http: // < the address of the server >
To pass from one page Web to another - an interesting way of research World Wide Web, however you early or late need to find something concrete. But thus it to make it will be not possible. In Internet there are special tools of Web-search.
Tools of search in WWW
Tools of search of the information in Internet, constructed on different principles and pursuing the different purpose, exists much. But all unites them that they settle down on the specially allocated network computers with powerful channels of communication(connection), serve every minute huge quantity(amount) of the visitors and require(demand) of the owners of significant expenses on support and updating. Nevertheless, almost all of them respond on searches of the users completely бескорыстно, and the sponsors and advertisers pay for this pleasure. On scales of influence on network community of retrieval systems, undoubtedly, are one of corner stones Internet.
The classification of retrieval systems is more convenient for building all on the basis of on the tax and processing of the information given to the users, - or else how many is automated in them, who types(collects) a database, in which the search is made: the people or computers.
2. Tools of search
internet search catalog
Conditionally tools of search are subdivided into search means of a help type (directories) and retrieval systems in the pure state (search engines).
2.1 Thematic catalogues
The search tools of the first type name subject, or thematic catalogues more often. The company owning such catalogue, continuously conducts huge work, investigating, describing, cataloguing and displaying on half-glasses contents of WWW-servers and other network resources scattered worldwide. Result her(it) titanium of efforts is the constantly updated hierarchical catalogue, at the top level the most general(common) categories, such as “business” are assembled, "”science", "”art" etc., and the elements of the lowermost level represent the links to separate WWW-pages and server together with the brief description of their contents.
Guarantees that such catalogue really covers all contents WWW, nobody will give, however possible(probable) not the completeness and selection of materials is with interest expiated there, that for the present not under force to any computer - intelligence of selection.
The subject catalogues give also opportunity of keyword search. However search this occurs not in contents of WWW-servers, and in their brief descriptions stored(kept) in the catalogue.
The subject catalogues Internet can be counted literally on fingers, as their creation and support require(demand) huge expenses. To most known concern Yahoo, WWW Virtual Library, Galaxy and some other.
Is most popular in the population Internet the catalogue Yahoo. On the first page Yahoo, located to the address http://www.yahoo.com, you receive access to two basic method of work with the catalogue - keyword search and hierarchical tree of sections.
Having begun descent(release) on sections of the catalogue, you will see, that each section contains the precisely same field for input of keywords and button Search, starting search.
Each section can include as transfer included in him(it) and actually links to pages concerning at once all section, with their brief descriptions.
Instead of travel you can at once get in the necessary place of the catalogue Yahoo with the help of search. Having entered one or several keywords divided(shared) by blanks, in a line of search and having pressed the button Search, you receive the list all in Yahoo, that comprises the specified keywords. This list will be divided(shared) into two parts - “categories” and “sites”.
If total of the links returned as a result of search, exceeds 25, the list of the links will be broken on some parts.
But not seldom happens so, that the list, given out by the machine, is very great and to see (overlook) it(him) simply not really. An output(exit) from this situation can become stricter selection of the information brought in the catalogue. One of most known such systems - catalogue Magellan to the address: http: // www.mckinley.com
This database contains the items of information on 80 thousand WWW-pages - that very much not much in comparison with those in millions, which exist in a network. However if Yahoo as the description of a resource uses one - two lines of the text, the employees of system Magellan on some of pages brought in their database, write the small reviews, and also estimate quality of these information resources on a five-mark scale. Till past bases of the reviews, Magellan owns as an own automatic index, for search in which it is necessary to throw the switch under a field of input in a rule(situation) entire database.
As a rule search represents one or several keywords divided(shared) by blanks.
The service, similar by the principles, of firm Point (http: // www.pointcom.com) in general basic emphasis does(makes) not on search, and on work with the thematic catalogue.
The service Point is known in a network for that its(her) employees are constantly engaged оцениванием of network resources and conduct the lists of those sites, which they consider(count) belong to “ to the best five percents(interests) WWW ”.
Firm Point Conducts a shared database all “ of five-percentage WWW-pages, where about everyone it is possible to read the detailed license.
The most old subject catalogue WWW is the catalogue Virtual Library:
http: // www.w3.org/hypertext/DataSources/bySubj ect/Overview.html
This system full enough covers a scientific layer WWW - servers of universities, laboratories and educational institutions.
Russia-On-Line Subject Guide.
For the users in our country the certain interest can represent the thematic catalogue Russia-On-Line Subject Guide, located to the address http://www.online.ru/rmain. This catalogue contains rather motley assembly of the links on foreign sources plus the thematic review of the Russian and Russian resources WWW.
2.2 Automatic indexes
It is possible to approach to a problem of search of the information in Internet and on the other hand. There are programs in which have loaded some thousand well-known URL-addresses. Being is started on the computer with access to WWW, this program begins automatically to download from a network the documents on it URL, and from each new document she(it) takes all links, contained in it,(him,) and adds them in the base of addresses. As at the end all WWW the documents are connected among themselves, early or late such program will bypass all Internet.
Certainly, the program can not understand as or classify that she(it) sees in a network. The programs of such type refer to as robots. They are limited to the tax of the statistical information and construction indexes in the texts of the documents. The database, collected by the robot, - index - stores (keeps) in it, simply speaking, item of information on that in what WWW-documents to contain those or other words.
Such the automatically collected index also underlies retrieval systems of the second sort, which frequently and name - automatic indexes.
The automatic index consists of three parts: the program - robot collected by this robot of a database and the interface for search in this base, with which the user works. All these components quite can function without intervention of the man.
As any classification of materials in such systems are absent, it is necessary to resort to them only then, when you precisely know keywords concerning that it is necessary, - we shall tell, a surname of the man or it is enough some of rare terms from the appropriate area. If to set search on the a little widespread words, you will have not enough life to bypass all URL-addresses, received as a result of search, - for example, the index of system Alta Vista contains of 11 billions words taken from 30 millions of WWW-pages.
An automatic index of WWW-pages exists much: WebCrawler, Lycos, Excite, Inktomi, Open Text and others. Some of them (for example, Lycos) represent more or less successful synthesis of the subject catalogue and automatic index.
Its(her) address http://altavista.digital.com. This system has appeared in December 1995. She (it) one of largest on volume of indexes from all such retrieval systems both most powerful and floppy rules of construction of searches. Alta Vista understands two different languages of searches rather strongly distinguished from each other. On the first page Alta Vista you see the form for simple search (Simple Search), and the panel of heading at the top of page contains the button Advanced Search, having pressed which, you receive the form for complication of search.
Except for WWW-pages, Alta Vista conducts a separate index for clauses from more than 14000 conferences Usenet (including hierarchy of groups relcom. *).
Search Alta Vista: that Alta Vista worked on group of words, only when they cost(stand) beside, it is necessary to conclude this group in inverted commas. If it is necessary to exclude from result all documents containing a certain word, it is necessary to attribute this word with is familiar “minus”.
The word without any mark works in search precisely the same as also it with is familiar “plus”.
As against Yahoo, by default Alta Vista searches of entry of the whole words. The ordered terms should stand in the document separately, instead of to be a part of other chains of symbols. If you need to find of all entry of a word, even when it is included into structure of other words, use a symbol *. The asterisk can stand only at the end of a word, and prevent giving many (too much) of results, Alta Vista requires(demands), that the word which is coming to an end on *, should consist not less than of 3 letters. Moreover, a symbol * allows to find not any termination (ending) of a word, but only not exceeding length of five symbols and not containing of capital letters or figures.
Results of search Alta Vista, as well as Yahoo, gives out as the list of the links on the documents, but instead of the description of each document near to his(its) heading you will see simply first some lines of his(its) text. If will be found more than 10 documents, Alta Vista will break their list on pages till 10 links on everyone. Alta Vista sorts the links so that on the first place there were “most important” documents with your keywords at definition of a degree of importance taking into account the following factors:
Whether the keywords into heading of the documents enter;
Whether these words in the first several lines of the documents contain;
As far as are close to each other in the text the keywords are found out.
Info seek, entered in of operation at the end of 19996 years, is somewhat reminiscent Alta Vista, however volume of the complete texts, surveyed by him,(it,) of the documents yet does not exceed 30 million. Web-pages. The address: http://www.infoseek.com. It is rather powerful system having high speed and idle time in circulation. Opportunities of drawing up of search almost same, as well as in Alta Vista, but not so rich. At almost complete preservation of values of marks "«plus", "«minus" and "«inverted commas", sensitivity to a difference header both lower case letters and opportunity to limit search to fragments Web- of pages, Info seek yet has no ability to define(determine) beside the worth terms (there is no operator NEAR), to limit search by date of updating a source and, main, to truncate terminations(ending) the key terms.
But the given retrieval system contains weight of facultative functions., for example, opportunity concerns to those to define(determine) quantity(amount) of the links in WWW on concrete page, that is to judge, as far as she(it) is popular or, on the contrary, to find out, how many links to external pages contain on the given site, more correctly, how many from them are reflected in index files Ultra seek. Use of special function Image seek allows to find in Internet of the image (figures, photo) on the certain subject. Info seek has also one of the best directories of resources of a Network.
By one of powerful search means in World Wide Web can attribute (relate) HotBot, containing the items of information on the complete texts 110 million. Pages. The address: http://www.hotbot.com. HotBot belongs to the newest systems, therefore his (its) profound search gives amazingly ample opportunities for detailed elaboration of search. It is reached (achieved) at the expense of use of the multistage menu offering various variants of drawing up of the search instruction. It is possible to carry out search on presence in the document one or several terms, search on a separate phase, search of the concrete person or links to the certain electronic address. For the greater detailed elaboration of search probably application of conditions SHOULD (can contain), MUST (should necessarily contain), MUST NOT (should not contain) in relation to any concepts. Besides HotBot represents возможность ограничить search by date of creation or last updating of the document, on geographic a rule(situation) of the server. Top of service opportunities is the search of the documents containing certain types of files, for example video. For this purpose it is necessary only to make a mark in special item of the menu of search.
It is one more tool of search such as search-bot (search the robot). The address: http: // www.webcrawler.com. The search here is very simple. Enter maximal keywords into a field of search, press Search.
It is the large database that contents of all pages, found by Web.
The address: http://www.lycos.com.
World Wide Web Worm
You will find this tool of search on http://www.cs.colorado.edu/home/mcbryan/wwww.html. It is one more extensive index of sites Web.
In each concrete case it is expedient to use the tool of search. You should try to carry out(spend) search through one tool and, if you have not received results, to pass to another. But nevertheless what tool to use? First of all it is better to take advantage of the thematic catalogue such as Yahoo, size at them rather small, but the speed is great. If to find the necessary information it was not possible, it speaks that you are interested in a too narrow subject, or badly correspond with your subject the keywords, chosen by you. It does not mean, that the necessary information in WWW is not present - it will be simple to find her(it) more difficultly. For its(her) search to you will be reached to take advantage of more primitive, more automatic and consequently by more universal systems such as Alta Vista.
2.3 Russian retrieval systems
The retrieval systems of global scale concentrate the basic attention on English resources of a Network. The task of search of the information on servers within the limits of the separate countries is carried out with systems of local character specially adapted for features of concrete languages. There are similar search means and in Russia. All of them are united by (with) an opportunity of processing of materials in all Cyrillic codes*. However on capacity and level of offered service the Russian retrieval systems considerably differ from each other.
Rambler, "Апорт" and "Яndex" now concern to leading group systems.
Among favorites is allocated Rambler (http://www.rambler.ru), becoming with the first professional domestic retrieval system. This system provides full text search on 3 million. Pages located on more than 15 thousand Web sites of Russia and the countries of near foreign countries. Besides Web-servers, the week archive of news of hierarchy relcom is surveyed also.
Rambler has close to an optimum conclusion of results of search. Even in a normal form the link on found object inserts the complete information. The system is designed in such a manner that the same document in the various coding is shown in the various coding are shown only once, and his(its) concrete addresses are summarized in the list. it's a reduces time on analyze of the received results because of absence of duplication of the same documents.
The main lack Rambler consists in impossibility to carry out search on the whole phase or even to specify in searches limiting distance of the required terms from each other. The casual combination of completely untied words results in distribution of the links on the documents, are absolutely not relevant to search.
The retrieval system Апорт (http://www.апорт.ru) is supplied with weight of various functions carrying her(it) number user-friendliest.
One consists of the main advantages Апорт in ample opportunities of drawing up of search. Besides the traditional operators "both" and “or”, search on the whole phase, the system is capable to isolate combinations of the terms located in the text by a number (line) with each other. Апорт offers an opportunity of machine translation of search with Russian on the English language and on the contrary. Both Rambler, and Апорт are capable to allocate the same document in the various coding and to give out the link to him (it) only of time, listing(transferring) concrete addresses in the list URL. Unfortunately, thus the items of information on the out-of-date versions of the same page in time do not leave which are listed (transferred) as existing, having a difference only in date of updating. One more lack of this system is not always correct processing of the names of pages, because of what as a result of search the document without the name » frequently is underlined «.
Retrieval system Яndex (http://www.yandex.ru), where besides servers of domains «ru< and «su< Яndex индексирует the contents of foreign Russian Web-sites.
The main distinctive feature of this system is the deep morphological analysis of the process able terms. The most powerful linguistics allows to take into account practically all possible (probable) shades of the use of keywords and to make search maximum precisely. Яndex has the good mechanism of recognition of one document in the several coding or on mirror servers.
After leading Russian тройкой there are some more search means, among which “ the Russian machine of search ” (http://search.interrussia.com), "«TELA-search" (http://tela.dux.ru/) and Russian Internet Search (http://www.search.ru). While all these servers do not differ neither breadth of search, nor by comfort, and can be used only as addition to conducting search means.
The search service in the Russian block Internet, as well as all over the world, develops promptly. There is no doubt, that in the near future parameters of existing systems will be raised, the new generations of search means giving to the users still (even) the large opportunities will appear.
Размещено на Allbest.ru
Возможности Search: управление документами и данными об изделиях, маршрутизация документов и заданий; основные параметры документа. База данных объектов и информационная поддержка их жизненного цикла. Интерфейс пользователя, редактирование спецификаций.
отчет по практике [1,7 M], добавлен 23.12.2009
Использование теории графов для решения задач. Информационные структуры входных и выходных данных. Иерархическая схема программы. Руководство оператора: назначение и условия выполнения программы. Граф-схема FormCreate, Found, RassUpdate и Search.
курсовая работа [2,5 M], добавлен 07.08.2013
Використання структурно-орієнтованого підходу при написанні програм на мові Сі та Паскаль, тестування та відладки, оформлення документації на програмну розробку. Побудова ефективних алгоритмів для розв’язку типових задач. Процедури пошуку (search).
курсовая работа [199,5 K], добавлен 14.01.2016
Gopher-система - предшественник World Wide Web. Электронная почта как вид Internet-сервиса. Телеконференции UseNet, протоколы передачи файлов FTP. Поиск информации в Интернет. Сервисы общения IRC и многопользовательские игры MUD. Internet-телефония.
реферат [20,1 K], добавлен 14.05.2011
Состав и организационное обеспечение Internet. Доменная система имен. Программное обеспечение и ресурсы Internet. Основные понятия World Wide Web. Поисковые машины, FTP файлы, оболочка Gopher. Средства виртуального общения. Основные термины в Internet.
реферат [57,3 K], добавлен 01.04.2011
История развития сети Internet. Общая характеристика сети Internet. Протоколы. Услуги предоставляемые сетью. Internet - мировая сеть. Компьютерная зависимость. Internet-2. Нехватка мощностей Internet. Создание Internet-2. Структура Internet-2.
контрольная работа [19,5 K], добавлен 06.10.2006
Основная информационная система в Интернете - World Wide Web (WWW) или Всемирная Паутина. Домены организационного и географического уровня. Программа Internet Explorer фирмы Microsoft для использования Интернета: настройка программы и принципы работы.
курсовая работа [503,3 K], добавлен 16.06.2009
Internet. Протоколы сети Internet. Принцип работы Internet. Прикладные программы. Возможности в Internet? Правовые нормы. Политика и Internet. Этические нормы и частная коммерческая Internet. Соображения безопасности. Объем сети Internet.
дипломная работа [128,8 K], добавлен 23.06.2007
Что такое Internet? Internet, как средство массовой информации. Службы Internet. Сетевая пресса. Структура Полит.Ру. Статистика. Рейтинг. Из чего состоит Internet? ICQ – новая возможность общения. Административное устройство Internet.
реферат [20,2 K], добавлен 10.05.2003
Java Script как язык управления сценарием отображения документа. Отличие world wide web от остальных инструментов для работы с Internet. Использование каскадных таблиц стилей в рамках разработки спецификации HTML. Элементы программы Netscape Navigator.
контрольная работа [1,1 M], добавлен 02.12.2009