The Secret Agent Man

Using Mata Hari

When you launch Mata Hari, it displays the clean and simple Main Screen, as pictured in Exhibit 1. The Main Screen lets you enter up to two queries for simultaneous processing at a group of user-definable search engines. The tabs across let you specify filtering to eliminate results from foreign countries, select particular groups on the Internet to search, set the default location of files, and choose a database containing results from a previous search.

To test Mata Hari’s intelligence gathering abilities, I decided to investigate information about underwater listening technology (for my next mission aboard a submarine in the Mediterranean). I could have entered a single a query, like "submarines AND (sonar OR hydrophones)." But this search statement is too limiting because it would only return documents that contain the words "submarines" and "sonar" or "Submarines" and "hydrophones."

My desire, however, was to find all the information available about underwater listening devices. So, I opted to use two queries instead. I began by entering "submarine OR submarines AND NOT movie" into the Query 1 input box of the Main Screen. I used the Boolean operator "AND NOT" and the keyword "movie" in an effort to avoid receiving search results about submarine movies.

I soon discovered that constructing an accurate Boolean expression is a complicated and confusing process. Fortunately, Mata Hari provides a convenient dialog for displaying the actual Boolean expression that will be sent to the search engines, as shown in Exhibit 2. This dialog reveals the sequence of processing by the arrangement of parentheses. In my case, the parentheses show that the "AND NOT movie" portion of the query will only apply to the second keyword "submarines" and not to the earlier keyword "submarine."

Once I realized the mistake, it was easily corrected by placing a set of parenthesis around the first two keywords to ensure that the word "movie" would not appear in any of my documents. Since I also wanted to find information about underwater listening-devices, I entered a second search statement "sonar OR hydrophones" in the Query 2 input box and then clicked the Search button. Within seconds, the Search Progress Details window appeared, displaying the status of my ongoing search, as shown in Exhibit 3.

When all the search engines finished reporting their results and the matching pages were downloaded into a local database on my computer, Mata Hari displayed the Results Details window, as illustrated in Exhibit 4. This window provides a host of handy features for analyzing search results and refining queries. The Scoring tab displays detailed information on the statistics used to score the document relevance, the Terms tabs lists keyword frequency to help identify other useful keywords to refine your queries, and the Statistics tab provides a summary of how the search engines performed.

One key advantage of using two queries to search is the ability to "turn-off" one of the queries. When I switched off the search statement about submarines, I was immediately able to view information about sonar and hydrophones not used on submarines, such as surface ship sonar. Conversely, I found Web pages that mentioned underwater submarine listening without mentioning the words "sonar" or "hydrophones." As Jerry puts it, "The ability to breakup and put together queries combined with simultaneous access to multiple search engines is very powerful in surveying much of the net. These options let you better corral your search topic more quickly by letting you slice and combine the effects of your queries individually and together."

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