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จัดท าโดย

อาจารย์ศรีอร เจนประภาพงศ์

สาขาวิชาสารสนเทศศึกษา คณะมนุษยศาสตร์

มหาวิทยาลัยหอการค้าไทย

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เป็นเว็บไซต์ที่จัดท าขึ้นเพื่อใช้เปน็เครื่องมือค้นหาแฟ้มข้อมูล (Files) ต่าง ๆ บน Internet

Files ต่างๆ ถูกรวบรวมโดยโปรแกรมหรือซอฟต์แวร์ (computer program) ที่เรียกว่า Robot, Spider, Crawler, Wanderer, หรือ Worm.

บางทีเรียกว่า search engine service หรือ search service

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จากนั้นก็ท าดรรชนี (Index) ช่วยค้น จากแฟ้มข้อมูลที่จัดเก็บไว้ (Title, Fulltext, Size, URL etc)

There is no selection criteria for the collection of files.

โปรแกรมหุ่นยนต์ ก็จะลัดเลาะไปตามเครือข่ายใน Internet เพื่อเก็บข้อมูลของเว็บไซต์ต่างๆมาไว้ในฐานข้อมูลของตน

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http://www.internettutorials.net/world-of-search-engines.asp

A search engine is a searchable database of Internet files collected by a computer program, called a crawler, robot, worm, or spider.

Indexing is created from the collected files, e.g., title, full text, date last modified, URL, language, etc.

Results are ranked by relevance; this will vary among search engines.

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Search Engines: are tools that help you to find things on the Internet. One example of a popular search engine is Google.

(http://www.sag.org/content/new-media-glossary)

Search Engines:Web services which help search through Internet addresses for user-defined terms or topics in which you are interested. (www.starrsites.com/glossary.htm)

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A web search engine is designed to search for information on the World Wide Web.

The search results are usually presented in a list and are commonly called hits.

The information may consist of web pages, images, information and other types of files.

Some search engines also mine data available in databases or open directories.

Unlike Web directories, which are maintained by human editors, search engines operate algorithmically or are a mixture of algorithmic and human input.

(http://en.wikipedia.org/wiki/Search_Engines)

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Search Engines ประกอบด้วย 3 ส่วน

1. Spider: โปรแกรมที่ท่องไปในเว็บ เพื่อเก็บข้อมูลเว็บใหม่ๆ / ที่ปรับปรุง มาจัดเก็บไว้ในฐาน(Program that traverses the Web from link to link, identifying and reading pages)

2. Index: ฐานข้อมูลประกอบด้วยส าเนาของเว็บเพจต่าง ๆ ที่ Spider รวบรวมมาจัดเก็บไว้ (Database containing a copy of each Web page gathered by the spider)

3. Search and retrieval mechanism: เทคโนโลยีช่วยในการสืบค้นค าค้นในฐานข้อมูล ----> แสดงผลการสืบค้นตามล าดับที่เกี่ยวข้องที่หน้าจอ

(Technology that enables you to search the index and that returns results in a relevancy-ranked order )

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In essence, a search engine consists of three components:

Spider: Program that traverses the Web from link to link, identifying and reading pages

Index: Database containing a copy of each Web page or other file gathered by the spider

Search and retrieval mechanism: Technology that enables you to search the index and that returns results in a relevancy-ranked order

(http://www.internettutorials.net/world-of-search-engines.asp)

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There are two major types of search engines:

•Individual: An individual engine uses a spider to collect its own searchable index.

•Meta: A meta engine searches multiple individual engines simultaneously. It does not have its own index, but uses the indexes collected by the spiders of other search engines. This type of engine is covered later in this tutorial under the topic of Meta Search Engines.

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ตัวอย่าง Meta Search Engine

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When you have a well-defined topic or idea to research

When your topic is obscure

When you are looking for a specific site

When you want to search the full text of millions of Web pages

When you want to retrieve a large number of Web sites on your topic

When you want to search for particular types of documents, sites, file types, languages, date last modified, geographical location, etc.

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ใช้ Search Engine ค้นหาหัวข้อที่มีลักษณะเฉพาะเจาะจง เช่น John Lennon, French wine, digital libraries projectเป็นต้น ซึ่งอาจหาไม่พบ หรือได้ผลการสืบค้นเป็นเว็บไซต์เพียงจ านวนหนึ่งหากใช้ Subject Directories

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ได้รายชื่อเว็บไซต์ หรือเว็บเพจจ านวนมากเกินความต้องการ / มีทั้งเกี่ยวข้องน้อย หรอืไม่เกี่ยวข้องเลย

ต้องใช ้เทคนิคการค้นคืน ที่ซับซ้อนมากขึ้นเพื่อก าจัดไซต์ที่ไม่ต้องการออกไป เช่น

Boolean Logic (and or not / and not)

Exact Phrase (“…….”)

Wildcard (* ?)

การค้นระบุเขตขอ้มูล (Fields) เช่น url:ozone title:rose เป็นต้น

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http://www.internettutorials.net/world-of-search-engines.asp

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วิธีการสืบค้น 1. Search พิมพ์ค าค้นในช่อง Search

1.1 การสืบค้นขั้นพื้นฐาน (Basic Search)1.2 การสืบค้นขั้นสูง (Advanced Search)

2. Browse การสืบค้นแบบไล่เรียงไปตามหมวดหมู่ (Categories หรือ Directories หรือ สารบบเว็บ) จากหมวดหมู่ใหญ่ --> หมวดหมู่ย่อยเรื่อย ๆ จนกระทั่งพบเว็บไซต์ที่ต้องการ

(ดูจาก Help)

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ต่อไปอธิบายวิธีการสืบค้นของ SEARCH ENGINES

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Basic Search

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Basic Search

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Basic Search

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Basic Search

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Basic Search

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Advanced Search

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Advanced Search

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Advanced Search

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Advanced Search

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ต่อไปอธิบายเทคนิคการสืบค้นของ SEARCH ENGINES

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Basic Search Techniques

http://www.internettutorials.net/basic-search-techniques.asp

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1. Identify your concepts When planning your search, break down your topic into its

separate concepts. Let's say you're interested in the effects of global warming on crops. In this case, you have two concepts: GLOBAL WARMING and CROPS.

Before you search, make a plan!Putting together a search is a three-step process.

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2. Make a list of search terms for each concept Once you have identified your concepts, list the terms which

describe each concept. Some concepts may have only one term, while others may have many.

global warminggreenhouse effectgreenhouse gasesclimate change cropscrop yieldscrop productionfood supply

These lists are a suggestion. Depending on the focus of your search, there may be other terms more suited to what you're looking for.

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3. Specify the logical relationships among your search terms

Once you know the words you want to search, you need to establish the logical relationships among them using Boolean logic: AND, OR, NOT.

To keep things simple, you don't need to use all the words you've compiled in a single search. The words are there to help you experiment with different searches until you find what you want.

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Boolean AND search

Let's start with a very simple two-word search. In this type of search, we want Web pages that contain both of our search terms. This is Boolean AND logic. This is probably the most common type of search that people want to do.

In our example, we're asking for documents that contain the words rain and snow. To do this, we simply type the two words into the search box with a space between them. This is the default logic on Google and nearly all other general search engines on the Web.

Notice how both words appear in the results. This is exactly what we wanted.

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A variant of an AND search is the plus sign (+). In many search engines, the plus sign signals an AND search. It guarantees that the words or phrases you include in your search will appear in your search results. For example, +rain +snow. In most search engines, you don't need to use the plus sign - the search engine will assume it. But it doesn't hurt to use it.

Google takes the plus sign seriously. If you include the plus sign, it will search for your words exactly as you have typed them. This keeps Google from adding synonyms to your search to bring in a wider set of results. In other words, the plus sign disables the synonyms feature.

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Boolean OR search

What if we want results that include either the word rain orthe word snow? This calls for Boolean OR logic. An easy way to ensure this is to use the advanced search page. Most search engines have such an option and it's very useful. Notice how the two search terms were typed into the line one or more of these words.

The search results include pages with just the word rain or just the word snow, exactly as we wanted.

Google requires that the word OR be typed in CAPITAL LETTERS. So do some other search engines. Since this may not be easy to remember, it's best to go to the advanced search page and let the search engine do the rest.

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Boolean NOT search

Sometimes you want to retrieve documents that do not contain a particular word. This can help when associated words are not really relevant and can muddy the focus of your results. To do this, place a minus sign (-) in front of the word you want to exclude.

Let's go back to our rain-snow example. In this case, we want documents that contain the word rain, but not the word snow. So, we've placed the minus sign immediately in front of the word snow:

rain -snow

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Beware!

(1) You may end out excluding relevant pages with this technique. Proceed with care.

(2) You many also end out with results that you don't want. When you look at the results screen above, you see that the term

rain has different meanings. To search for the weather phenomenon of rain, it would be a good idea to add a semantically meaningful word such as weather, storm or the like.

The more specific your terminology, the better your results will be.

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Phrase Search

Some words naturally appear in the context of a phrase, for example, freedom of the press. To search on phrases in most search engines, simply enclose the phrase within double quotes:

"freedom of the press"Phrases are especially important when there are stop words in

your search. These are "little" words such as a, and, the, in, it, etc. Most search engines tend to ignore these words. If you want to be sure they are included in your search results, enclose them with the rest of your search within quotation marks. You can also put a plus sign (+) in front of them. Yahoo! suggests a combination of quotation marks and the plus sign, e.g., "+in thing".

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Field Search

Field searching is an optional way to focus your search results. With general search engines, you're searching the full text of many millions of pages, and field searching can help you retrieve results that may be more manageable.

For example, you can search for words that appear within a particular Web site, within the URL (Web address), in the page title, and so on.

The exact technique for doing this can differ among search engines, so be sure to check out the Help pages before proceeding.

Let's consider a couple of examples on Google.

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Notice that all the results come from the site nasa.gov. You can also go to the advanced search page on Google to conduct this search.

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Natural language search

A few search engines encourage you to type your search as a "normal" question or sentence, rather than concern yourself with Boolean logic.

This is sometimes known as a natural language search. On these engines, a variety of sophisticated techniques are working behind the scenes to analyze your search and return relevant results.

Hakia is a good example of this type of engine. Give it a try and see what you think.

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Fill in the blanks (*)

The *, or wildcard, is a little-known feature that can be very powerful.

If you include * within a query, it tells Google to try to treat the star as a placeholder for any unknown term(s) and then find the best matches.

For example, the search [ Google * ] will give you results about many of Google's products (go to next page and next page --we have many products).

The query [ Obama voted * on the * bill ] will give you stories about different votes on different bills. Note that the * operator works only on whole words, not parts of words.

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การค้นโดยระบุต าแหน่ง / เขตข้อมลู (Fields) เช่น

ค าสั่ง ตัวอย่าง

intitle: intitle:information studiesallintitle: allintitle:/information/studieslink: link:www.prince-damrong.moi.go.threlated: related:http://www.culture.go.th/www/th/define: define:literature

(ค้นหาความหมายของค าศัพท์ภาษาอังกฤษ)

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1. Bet Search Tips(http://www.internettutorials.net/best-bet-search.asp)

อ่านเพิ่มเติมที่

2. Boolean Searching on the Internet(http://www.internettutorials.net/boolean.asp)

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link:www.google.com

ต้องการเว็บไซต์ที่ link ไปยังเว็บของ Google

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ต้องการเว็บไซต์ที่มีเนื้อหาจัดอยู่ในกลุ่มเดียวกันกับ “ส านักงานวัฒนธรรมแหง่ชาติ”

related:http://www.culture.go.th/www/th/

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http://www.m-culture.go.th/culture01/cindex_1.php

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http://www.ocac.go.th/

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http://www.finearts.go.th/th/indexOriginal.php

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Meta Search Engines

Dogpile Ixquick

Mamma MetaCrawler

ฯลฯ

วิธีการสืบค้น

1. Basic Search

2. Advanced Search

Basic Search

Advanced Search

(http://ixquick.com/)Basic Search

Power Search

Expert Search

(http://www.metacrawler.com/)

Basic Search

Advanced Search