-- 发布时间：3/27/2007 9:49:00 AM
-- Google是一种语义搜索引擎吗？
http://www.readwriteweb.com/archives/is_google_a_semantic_search_engine.php
Is Google a Semantic Search Engine?
Written by Guest Author / March 26, 2007 /
Written by Phill Midwinter, a search engineer from the UK. This is a great follow-up to our article last Friday, [URL=http://www.readwriteweb.com/archives/hakia_takes_on_google_semantic_search.php]Hakia Takes On Google With Semantic Technologies[/URL].
What is a Semantic Engine?
Semantics are said to be ‘the next big thing’ in search engine technology. We technology bloggers routinely drum up articles about it and sell it to you, the adoring masses, as a product that will change your web experience forever. Problem is, we often forget to tell you exactly what semantics are - we just get so excited. So let's explore this...
Wikipedia says:
“Semantics ([URL=http://en.wikipedia.org/wiki/Ancient_Greek]Greek
[/URL] semantikos, giving signs, significant, symptomatic, from sema, [URL=http://en.wikipedia.org/wiki/Sign]sign[/URL]) refers to the aspects of [URL=http://en.wikipedia.org/wiki/Meaning_(linguistic)]meaning[/URL] that are expressed in a [URL=http://en.wikipedia.org/wiki/Language]language[/URL], [URL=http://en.wikipedia.org/wiki/Code]code[/URL], or other form of representation. Semantics is contrasted with two other aspects of meaningful expression, namely, [URL=http://en.wikipedia.org/wiki/Syntax]syntax[/URL], the construction of complex signs from simpler signs, and [URL=http://en.wikipedia.org/wiki/Pragmatics]pragmatics[/URL], the practical use of signs by [URL=http://en.wikipedia.org/wiki/Agent]agents[/URL] or [URL=http://en.wikipedia.org/wiki/Community]communities[/URL] of interpretation in particular circumstances and contexts. By the usual convention that calls a study or a theory by the name of its subject matter, semantics may also denote the theoretical study of meaning in systems of signs.”
...which is absolutely no help.
Semantics as it relates to our topic, search engines, actually covers a few closely related fields. In this instance what we are looking at deciphering (as a basic example) is whether a computer can discern if there is a link between two words, such as cat and dog. You and I both know that cats and dogs are common household pets, and can be categorized as such. The human brain seems to comprehend this easily, but for a computer it is a much more complex task and one I won’t go into here - because it would most likely bore you.
If we take as read then, that the search engine now has semantic functionality, how does that enable it to refine its search capability?
It can automatically place pages into dynamic categories, or tag them without human intervention. Knowing what topic a page relates to is invaluable for returning relevant results.
It can offer related topics and keywords to help you narrow your search successfully. With a keyword like sport the engine would offer you a list of sports perhaps as well as sports related news and blogs.
Instead of offering you the related keywords, the engine can directly incorporate them back into the search with less weight than the user inputted ones. It’s still contested as to whether this will produce better results or just more varied ones.
If the engine uses statistical analysis to retrieve it’s semantic matches to a keyword (as Google is likely to do) then its likely that keywords currently associated with hot news topics will bring those in as well. For example, using my engine to search for the keyword police, brought up peerages (relating to the uk’s cash for honors scandal recently).
So, according to me:
“A semantic search engine is a search engine that takes the sense of a word as a factor in its ranking algorithm or offers the user a choice as to the sense of a word or phrase.”
This is not in line with the purists of what is known as ‘The Semantic Web’, who believe that for some reason we should spend all our time tagging documents, pages and images to make them acceptable for a computer to read. Well, I’m sorry but I’m not going to waste my time tagging when a computer is able to derive context and do it for me. I may have offended Tim Berners Lee by saying this, but as the creator of the Web he should know better.
How does Google match up?
Until extremely recently, Google’s semantic technology (which they’ve had now for quite a while) was limited to matching those adsense blocks to your website’s content. This is neat, and a good practical example of the technology - but not relevant to their core search product. However if you make a single keyword search today, chances are you may spot a block like this at the bottom of your results page:
This is more or less exactly what I was just writing about. They’re offering you alternatives based upon your initial search, which in this case was obviously for citizen. Citizen is a bank, a watchmaker and (if I’m not mistaken) it means you’re a member of a country or something. This is the first clear example of Google employing a semantic engine that works by analyzing the context of words in their index and returning likely matches for sense.
Some of you may be wondering why they aren’t doing this for multiple keyword phrases, which I can take a guess at from some of my own work. Analyzing the context of a word statistically is intensive and slow; and if you try and analyze two, you slow the process further and so on. It is likely they have problems doing so for more than one keyword currently, and Google as ever is cautious about changing their interface too radically too quickly. This implementation of semantics gives hope that they haven’t adopted the purist view of ‘The Semantic Web’ where everything is tagged and filed neatly into nice little packages.
Google is all too aware of the following very large problems with that idea:
Users are stupid.
Users are lazy.
Redefining the way they’ve indexed what is assumed to be petabytes of data would require them to effectively start again.
It’s not as powerful or dynamic.
How Google can utilize Semantic technologies
It’s my belief that Google will increasingly tie this technology into their core search experience as it improves in speed and reliability. It has some phenomenally powerful uses and I’ve taken the liberty of laying out a few of my suggestions on where they can go with this:
Self aware pages
Tagging pages with keywords has always been used on the internet to let search engines know what kind content the page contains.
Using a Google API we can generate the necessary keywords on the fly as the page loads. This cuts out a large amount of work for SEO.
A Google API enabled engine wouldn’t even need to look at these keywords, it could generate them itself.
Not only a page can be self aware these days, people tag everything - including links. The Google API could conceivably be used to tag every single word on a page, creating a page that covers every single keyword possibility. This is overkill - but a demonstration of the power available.
Narrow Search
When you begin a search, you enter just one or two keywords in the topic you’re interested in.
Related keywords appear, which you can then select from to target your search and remove any doubts about dual meanings of a word for example.
This step repeats every time you search, also possible is opinionated search.
Opinionated Search
Because of the way Google statistically finds the senses of keywords from the mass of pages in its index, what in fact it finds is the majority opinion from those pages of what the sense of a word is.
At the base level, you can select from the average opinion of related keywords and subjects from its entire index.
You can find the opinion at other levels as well though, and this is where the power comes in in terms of really targeting what the user is looking for quickly and efficiently. All the following mean that this is the first true example of social search:
Find the opinion over a range of dates, good for current events, modern history, changes in trends.
Find the opinion over areas of geography, or by domain extension (.co.uk, .com).
Find the opinion over a certain group of websites, or just one website in particular - compare that with another site.
Find the opinion not only over the above things but also subjects, topics, social and religious groups.
At the most ridiculous example level, you could even find what topics 18 year olds on myspace living in Leeds most talk about - but that I could probably guess. The point is that this is targeting demographics on a really unprecedented level.
Add the sites or web pages to your personal profile that you think most closely reflect your opinions, this data can then be taken into account in all future searches returning greater personal relevancy.
Conclusion
Google is using semantic technology, but is not yet a fully fledged semantic search engine. It does not use NLP (Natural Language Processing), but this is not a barrier to producing some truly web changing technology with a bit of thought and originality. NLP may well be (I hate myself for writing this) web 4.0 and semantics is web 3.0 - they are in fact different enough to be classified as such in my eyes and the technology [URL=http://www.readwriteweb.com/archives/hakia_takes_on_google_semantic_search.php]Hakia is developing[/URL] is certainly markedly distinct from Google’s semantic efforts.
There are barriers that Google needs to overcome... is it capable of becoming fully semantic without modifying it’s index too drastically; can Google continue to keep the results simple and navigable for its varied user base? Most importantly, does Google intend to become a fully semantic search engine and to do so within a timescale that won’t damage their position and reputation? I like to think that although the dragon is sleeping, that doesn’t mean it’s not dreaming!