Patent Publication Number: US-2002002899-A1

Title: System for content based music searching

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
     [0001] The present Application is related to the U.S. patent application entitled “METHOD FOR CREATING A DATABASE FOR COMPARING MUSIC ATTRIBUTES”, Ser. No. ______, Attorney docket Number M-8292 US filed on the same day as the present Application, and assigned to the Assignee of the present invention. The disclosure of the patent application “METHOD FOR CREATING A DATABASE FOR COMPARING MUSIC ATTRIBUTES” is hereby incorporated by reference in its entirety.  
     [0002] The present Application is also related to the U.S. patent application entitled “SYSTEM FOR CREATING A DATABASE FOR COMPARING MUSIC ATTRIBUTES”, Ser. No. ______, Attorney docket Number M 8408 US, filed on the same day as the present Application, and assigned to the Assignee of the present invention. The disclosure of the patent application “SYSTEM FOR CREATING A DATABASE FOR COMPARING MUSIC ATTRIBUTES” is hereby incorporated by reference in its entirety.  
     [0003] The present Application is also related to the U.S. patent application entitled “METHOD FOR CONTENT BASED MUSIC SEARCHING”, Ser. No. ______, Attorney docket Number M-8409 US, filed on the same day as the present Application, and assigned to the Assignee of the present invention. The disclosure of the patent application “METHOD FOR CONTENT BASED MUSIC SEARCHING” is hereby incorporated by reference in its entirety.  
     [0004] The present Application is also related to the U.S. patent application entitled “QUALITY ASSURANCE SYSTEM FOR SCREENING MUSIC LISTENERS”, Ser. No. ______, Attorney docket Number M 8546 US, filed on the same day as the present Application, and assigned to the Assignee of- the present invention. The disclosure of the patent application “QUALITY ASSURANCE SYSTEM FOR SCREENING MUSIC LISTENERS” is hereby incorporated by reference in its entirety. 
    
    
     
       SOFTWARE APPENDIX  
       [0005] This application is being filed with a software code appendix, which contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the software code or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever.  
       FIELD OF THE INVENTION  
       [0006] The present invention relates to computerized comparison of music based upon music content and listener perception of music attributes.  
       BACKGROUND  
       [0007] The Internet connects thousands of computers world wide through well-known protocols, for example, Transmission Control Protocol (TCP)/Internet Protocol (IP), into a vast network. Information on the Internet is stored world wide as computer files, mostly written in the Hypertext Mark Up Language (“HTML”). The collection of all such publicly available computer files is known as the World Wide Web (WWW).  
       [0008] The WWW is a multimedia-enabled hypertext system used for navigating the Internet and is made up of hundreds of thousands of web pages with images and text and video files, which can be displayed on a computer monitor. Each web page can have connections to other pages, which may be located on any computer connected to the Internet.  
       [0009] A typical Internet user uses a client program called a “Web Browser” to connect to the Internet. A user can connect to the Internet via a proprietary network, such as America Online or CompuServe, or via an Internet Service Provider, e.g., Earthlink.  
       [0010] A Web Browser may run on any computer connected to the Internet. Currently, various browsers are available! of which two prominent browsers are Netscape Navigator and Microsoft Internet Explorer. The Web Browser receives and sends requests to a web server and acquires information from the WWW. A web server is a program that, upon receipt of a request, sends the requested data to the requesting user.  
       [0011] A standard naming convention known as Uniform Resource Locator (“URL”) has been adopted to represent hypermedia links and links to network services. Most files or services can be represented with a URL. URLs enable Web Browsers to go directly to any file held on any WWW server.  
       [0012] Information from the WWW is accessed using well-known protocols, including the Hypertext Transport Protocol (“HTTP”), the Wide Area Information Service (“WAIS”) and the File Transport Protocol (“FTP”), over TCP/IP protocol. The transfer format for standard WWW pages is Hypertext Transfer Protocol (HTTP).  
       [0013] The advent and progress of the Internet has changed the way consumers buy music CDs. Consumers download digital music using MP3 or SDMI technology, with a click of a mouse, via the Internet. Audio delivery techniques have also made it easy to stream audio from a website to a consumer when a consumer demands.  
       [0014] Although audio delivery methods have become efficient, computerized searching techniques for music are still archaic. Professional and amateur artists have produced millions of music titles, however music searching techniques are comparable to antiquated text based searching techniques.  
       [0015] Music today can only be classified and searched under the name of the artist, album title, and music genre i.e., whether the music falls under the following categories: Alternative, Blues, Country, Folk, Gospel, Jazz, Latin, New Age, R&amp;B, Soul, Rap, Reggae, Rock, etc. If a consumer wants to search for music that has a lead female vocalist, with a prominent instrument, e.g., the saxophone, and the music is a cross-over between Pop and Country genres, the current searching techniques will fail to support such a request. Current search techniques cannot compare plural aspects of different genres and provide intelligent interactive! search techniques to music listeners.  
       [0016] Text-based search engines have worked well with databases because text can describe variables. However, text alone cannot help in searching music since music is difficult to define by text alone.  
       [0017] Besides music other aspects of our lives for example, cuisine, wine, paintings, movies, videos, and images etc., (collectively referred as “aesthetic commodities”) are also not easily searched by text based engines.  
       [0018] Hence what is needed is a system that can define various aspects of music and/or other aesthetic commodities and store attributes describing music and/or aesthetic commodities into a universal, coherent and perceptually relevant database that will allow content based searching.  
       SUMMARY  
       [0019] The present invention solves the foregoing drawbacks by providing a system for searching music, based upon music content that may be described by a plurality of predetermined feature vectors. The system includes a user interface that can receive a plurality of user requests for searching music, wherein the user requests defines a plurality of search parameters. A user enters search parameters into the user interface that allows a user to vary the plural levels of the plural feature vectors.  
       [0020] The system further includes a user interface engine that receives the user requests for searching music based upon user chosen feature vector levels, wherein the user interface includes a parser for parsing the user requests. The system also includes an inferential engine that performs a search for music by comparing the feature vectors describing music attributes. The system further includes a modeling module that performs a similarity analysis by comparing feature vectors.  
       [0021] Examples of some feature vectors used by the current system are:  
       [0022] An emotional quality vector describing the emotional reaction to music based upon whether music is Intense, Happy, Sad, Mellow, Romantic, Heartbreaking, Aggressive or Upbeat or other emotions;  
       [0023] A vocal quality vector describing the vocal quality of music, based upon whether music includes a Smooth voice, a Powerful voice, a Great voice, a Soulful voice, or other voice qualities;  
       [0024] A sound quality vector describing the sound quality of music, based upon whether music includes a Strong beat, is simple, or has a good groove, or is fast, or is speech like, or emphasizes a melody, or other sound qualities;  
       [0025] A situational quality vector describing the plural situations for which the music may be used, based on whether the music is, good for a workout, a shopping mall, a dinner party, a dance party, for slow dancing, or for studying or other situations;  
       [0026] A genre vector describing the music genre, based on whether the music is belongs to a plurality of genres including, Alternative, Blues, Country, Electronic/Dance, Folk, Gospel, Jazz, Latin, New Age, R&amp;B, Soul, Rap, Hip-Hop, Reggae, Rock or others;  
       [0027] An ensemble vector describing the music ensemble, based on whether the music includes a female solo, male solo, female duet, male duet, mixed duet, female group, male group or instrumental;  
       [0028] An instrument vector describing the music instruments, based on whether the music includes a includes an acoustic guitar, electric guitar, bass, drums, harmonica, organ, piano, synthesizer, horn, or saxophone or other instruments.  
       [0029] One of the advantages of the present system is that feature vectors can describe music content. This assists in creating a music space for various attributes of music.  
       [0030] Another advantage of the present invention is that since the feature vectors define music attribute, music can be searched based upon music content.  
       [0031] Another advantage of the present system is that, the feature vectors defining music attributes may be changed and hence music rating system is contemporary. This also makes the music search process interactive.  
       [0032] This brief summary has been provided so that the nature of the invention may be understood quickly. A more complete understanding of the invention can be obtained by reference to the following detailed description of the preferred embodiments thereof in connection with the attached drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0033]FIG. 1 illustrates a computing system to carry out the inventive technique.  
     [0034]FIG. 2 is a block diagram of the architecture of the computing system of FIG. 1.  
     [0035]FIG. 3 is a block diagram of the Internet Topology.  
     [0036]FIG. 4 is a block diagram of the various components used for creating a database structure according to one embodiment of the present invention.  
     [0037]FIG. 5A is a flow diagram of computer executable process steps for creating a database, according to the present invention.  
     [0038]FIG. 5B is a flow diagram of computer executable process steps for developing a questionnaire.  
     [0039]FIG. 5C 1  is a block diagram of a neural network as used by the present invention.  
     [0040]FIG. 5C 2  is a flow diagram of computer executable process steps showing various operations performed by the neural network, according to the present invention.  
     [0041]FIG. 5C 3  is a flow diagram of computer executable process steps showing various operations performed by a Modeling Module, according to the present invention.  
     [0042]FIG. 5D is a graphical representation of a plurality of music spaces created by the present invention.  
     [0043]FIG. 5E is a flow diagram of computer executable process steps showing various operations performed to calibrate a music listener, according to the present invention.  
     [0044]FIG. 5F is an example of storing listener responses to music samples, according to the present invention.  
     [0045]FIG. 5G is a flow diagram of computer executable process steps showing various operations performed to measure typicality of a music listener, according to the present invention.  
     [0046]FIG. 5H shows another example of storing listener responses.  
     [0047]FIG. 5I is a block diagram showing a quality assurance system, according to the present invention.  
     [0048]FIG. 6 shows sample data fields for collecting music listener information.  
     [0049]FIG. 7A 1  shows sample questions for a plurality of music listeners.  
     [0050]FIG. 7A 2  shows sample questions for a plurality of music listeners.  
     [0051]FIG. 7B shows sample questions asked to a plurality of expert music listeners for obtaining explicit similarity data for music samples.  
     [0052]FIG. 8A 1  shows sample questions for a plurality of expert listeners.  
     [0053]FIG. 8A 2  shows sample questions for a plurality of expert listeners.  
     [0054]FIG. 8A 3  shows sample questions for a plurality of expert listeners.  
     [0055]FIG. 9 is a block diagram of the overall system, according to another embodiment of the present invention.  
     [0056]FIG. 10A shows a sample User Interface, according to the present invention.  
     [0057]FIG. 10B shows a genre mixer, according to the present invention.  
     [0058]FIG. 10C shows an emotional quality mixer according to the present invention.  
     [0059]FIG. 10D shows a vocal quality mixer, according to the present invention.  
     [0060]FIG. 11 is a block diagram of a User Interface engine, according to another embodiment of the present invention.  
     [0061]FIG. 12 is a flow diagram showing computer executable process steps for conducting content-based search in the music domain.  
     [0062]FIG. 13 is a flow diagram showing process steps for performing content-based search for aesthetic commodities.  
    
    
     [0063] The use of similar reference numerals in different Figures indicates similar or identical items.  
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0064]FIG. 1 is a block diagram of a computing system for executing computer executable process steps according to one embodiment of the present invention. FIG. 1 includes a host computer  10  and a monitor  11 . Monitor  11  may be a CRT type, a LCD type, or any other type of color or monochrome display. Also provided with computer  10  is a keyboard  13  for entering text data and user commands, and a pointing device  14  for processing objects displayed on monitor  11 .  
     [0065] Computer  10  includes a computer-readable memory medium such as a rotating disk  15  for storing readable data. Besides other programs, disk  15  can store application programs including web browsers by which computer  10  connects to the Internet and the systems described below, according to one aspect of the present invention.  
     [0066] Computer  10  can also access a computer-readables floppy disk storing data files, application program files, and computer executable process steps embodying the present invention or the like via a floppy disk drive  16 . A CD-ROM interface (not shown) may also be provided with computer  10  to access application program files, audio files and data files stored on a CD-ROM.  
     [0067] A modem, an integrated services digital network (ISDN) connection, or the like also provides computer  10  with an Internet connection  12  to the World Wide Web (WWW). The Internet connection  12  allows computer  10  to download data files, audio files, application program files and computer-executable process steps embodying the present invention.  
     [0068] Computer  10  is also provided with external audio speakers  17 A and  17 B to assist a listener to listen to music either on-line downloaded from the Internet or off-line using a CD. It is noteworthy that a listener may use headphones instead of audio speakers  17 A and  17 B to listen to music.  
     [0069]FIG. 2 is a block diagram showing the internal functional architecture of computer  10 . As shown in FIG. 2, computer  10  includes a CPU  201  for executing computer-executable process steps and interfaces with a computer bus  208 . Also shown in FIG. 2 are a WWW interface  202 , a display device interface  203 , a keyboard interface  204 , a pointing device interface  205 , an audio interface  20 ) 9 , and a rotating disk  15 . Audio Interface  209  allows a listener to listen to music, On-line (downloaded using the Internet or a private network) or off-line (using a CD).  
     [0070] As described above, disk  15  stores operating system program files, application program files, web browsers, and other files. Some of these files are stored on disk  15  using an installation program. For example, CPU  201  executes computer-executable process steps of an installation program so that CPU  201  can properly execute the application program.  
     [0071] A random access main memory (“RAM”)  206  also interfaces to computer bus  208  to provide CPU  201  with access to memory storage. When executing stored computer-executable process steps from disk  15  (or other storage media such as floppy disk  16  or WWW connection  12 ), CPU  201  stores and executes the process steps out of RAM  206 .  
     [0072] Read only memory (“ROM”)  207  is provided to store invariant instruction sequences such as start-up instruction sequences or basic input/output operating system (BIOS) sequences for operation of keyboard  13 .  
     [0073]FIG. 3 shows a typical topology of a computer network with computers similar to computer  10 , connected to the Internet. For illustration purposes, three computers X, Y and Z are shown connected to the Internet  302  via Web interface  202  through a gateway  301 , where gateway  301  can interface N number of computers. Web interface  202  may be a modem, network interface card or a unit for providing connectivity to other computer systems over a network using protocols such as X.25, Ethernet or TCP/IP, or any device that allows, directly or indirectly, computer-to-computer communications.  
     [0074] It is noteworthy that the invention is not limited to a particular number of computers. Any number of computers that can be connected to the Internet  302  or any other computer network may be used.  
     [0075]FIG. 3 further shows a second gateway  303  that connects a network of web servers  304  and  305  to the Internet  302 . Web servers  304  and  305  may be connected with each other over a computer network. Web servers  304  and  305  can provide content including music samples, audio clips and CDs to a user from database  306  and/or  307 . Web servers  304  and  305  can also host the present music searching system, according to the present invention. Also shown in FIG. 3 is a client side web server  308  that can be provided by an Internet service provider.  
     [0076]FIG. 4 is a block diagram showing various components that may be used to develop a database that allows music listeners to search for music based upon music content, perceptual qualities of music and music attributes, according to one embodiment of the present invention. Listener perception data  401 , Instrument information data  402 , Expert Information data  403 , and Explicit Pairwise data  403 A are collected and then stored as Acquired data  404  and thereafter fed into a Research database  405  (also referred as “R&amp;D database”). Basic music fact data  402 A, including title of the music, category/genre if known, and date of 2  recording etc. is also sent to R&amp;D database  405 . Data describing music attributes may also be collected by Digital Signal processing (“DSP”) and stored as DSP data  403 B, Radio logging and stored as Radio logged data  403 D, and Internet Harvesting and stored Internet Harvested data  403  E, using Spider techniques.  
     [0077] Data from R&amp;D database  405  is sent to a Modeling Module  406  that creates a multi-dimensional music space based upon the acquired data, and performs a similarity analysis on the music samples, as described below in FIG. 5C 3 . Modeled data from  409  is sent to a production database  407  that stores music data and allows a listener to search music based upon plural attributes as described below. A similarity database  407 A is also shown that includes similar music sets that are not accurately modeled by Modeling Module  406 , as discussed below.  
     [0078] Creating a Production Database  
     [0079]FIG. 5A is a flow chart showing process steps to create a dynamic database that allows comparison of music, based upon music attributes/content and perceptual quality of music based upon data collected from actual music listeners. It is well known that music affects different people in different ways. Every piece of music provides listeners certain experiences including emotional experiences. The present invention provides descriptors/variables that can describe human experience while listening to music and link the variables/descriptors (via feature vectors) to specific music types/genres.  
     [0080] Data Collection from Music Listeners:  
     [0081] In step S 501 A, listeners are provided music samples either on-line via the Internet or on a CD-ROM, with a list of questions corresponding to the music samples. The questions are used to solicit listener responses that describe music attributes and assign values to feature vectors for the attributes. A listener using computer X (FIG. 3) may download music samples from a web server  304 / 305  with a list of questions. The present invention provides a questionnaire that evaluates the cognitive, emotional, esthetical, and situational effects of music on actual listeners.  
     [0082] Prior to providing music samples or questions, listener information may also be collected, as shown in FIG. 6. Before a listener can start listening to sample music, a training session may be conducted to familiarize a listener with the music rating process.  
     [0083] FIGS.  7 A 1  and  7 A 2  show an example of a list of questions that are provided to a listener prior to, after or while a listener is listening to the music sample. A listener that listens to more than one song is also asked to compare songs.  
     [0084] Examples of questions in FIGS.  7 A 1  and  7 A 2  may be grouped as follows:  
     [0085] Cognitive (Questions  700 A, FIG. 7A 1 ):  
     [0086] This song is similar to the previous song  
     [0087] I like this song  
     [0088] This tune sticks in my mind  
     [0089] This song is simple  
     [0090] This song tells a story  
     [0091] This song emphasizes the melody  
     [0092] This song emphasizes the vocals  
     [0093] This song is speech-like  
     [0094] This song has a strong beat  
     [0095] This song is fast  
     [0096] This song has a good groove  
     [0097] Emotion ( 700 B, FIG. 7A 1  and  7 A 2 ):  
     [0098] This song is intense  
     [0099] This song is upbeat  
     [0100] This song sounds aggressive  
     [0101] This song is relaxing  
     [0102] This song is mellow  
     [0103] This song is sad  
     [0104] This song is romantic  
     [0105] This song expresses a broken heart  
     [0106] Esthetics (Questions  700 C, FIG. 7A 2 ):  
     [0107] The singer has a smooth voice  
     [0108] The singer has a soulful voice  
     [0109] The singer has a powerful voice  
     [0110] The singer has a truly great voice  
     [0111] This song has a high voice  
     [0112] This song has a sexy voice  
     [0113] Social behavior (Questions  700 D, FIG. 7A 2 ):  
     [0114] This song would be good for easy listening  
     [0115] This song would be good for a wild dance party  
     [0116] This song would be good for slow dancing  
     [0117] This song would be good for a workout  
     [0118] This song would be good in a shopping mall  
     [0119] Other questions like  700 E (FIG. 7A 2 ) ask the listener if the listener knows the music or has a recording of the sample. Question  700 F (FIG. 7A 2 ) asks the listener if the listener can describe the situations where the music will be appropriate, and if the music sample reminds the listener of an artist(s) or song. Question  700 G (FIG. 7A 2 ) asks the listener to describe the song in other words.  
     [0120] Every question requires a response. Based upon listener response, a value is assigned to a feature vector that defines music attributes. Appendix “A” provides an example of assigning feature vector values to listener responses.  
     [0121] Data Collection from Music Experts:  
     [0122] Not every music listener is competent to rate and analyze music styles and instruments that are used in a music sample. Hence expert data  403  is collected from expert music listeners who may be individuals trained in the field of music or are more knowledgeable in the field of music than an average listener.  
     [0123] Referring back to FIG. 5A, in step S 501 B, expert data  403  is collected by providing music samples to experts accompanied by a plurality of questions. Music samples and questions to expert music listeners may be provided over the Internet, a private network and/or music CDs, etc. For example, a music expert using computer X (FIG. 3) may download music samples from a web server  304 / 305  with a list of questions.  
     [0124] FIGS.  8 A 1 ,  8 A 2  and  8 A 3  provide an example of the questions that a music expert may be asked for collecting expert data  403 . An expert may be asked questions  8 C 0 l (FIG. 8Al) to identify music genre, for example, whether a music sample belongs to, an Alternative, a Blues, a Country, an Electronic/Dance, a Folk, a Gospel, a Jazz, a Latin, a New Age, a R&amp;B/Soul, a Rap/Hip-Hop, a Reggae and a Rock style of music. The expert is not limited to choosing a single genre, instead, the expert may choose plural genres to identify a particular music sample.  
     [0125] Questions  801  establish the importance of a particular music style in a given sample, and also determine crossover between different genres. For example, if an expert that listens to a music sample and gives a high rating for Blues and Country in questions  801 , then the music sample may have a cross-over between Blues and Country style.  
     [0126] Within the various genres mentioned above, there may also be sub styles, for example, Gospel, Motown, Stax/Memphis, Philly, Doo-wop, Funk, Disco, Old School, Blue-eyed soul, Adult contemporary, Quiet storm, Dance/techno, Electro/Synthetic, New Jack Swing, Retro/Alternative, Hip Hop, Rap and Gangsta etc. Question  802  (FIGS.  8 A 1  and  8 A 2 ) requires an expert to rate music sub-styles. This determines the sub-genre of a music sample.  
     [0127] In question  803  (FIG. 8A 2 ), an expert identifies whether a music sample is instrumental or vocal. If music is primarily vocal, then the expert also identifies if the lead vocalist is a male or female. In question  804 , the expert describes backup vocalist(s), if any.  
     [0128] In question  805  (FIG. 8A 2 ), an expert describes a band, if any, associated with a music sample.  
     [0129] In questions  806 ,  807  and  808 (Figure  8 A 2 ), the expert identifies the three most important instruments that, may exist in a music sample.  
     [0130] In questions  809 (Figures  8 A 2  and  8 A 3 ), an expert is given standard statements and an expert either agrees or disagrees with various levels of conviction.  
     [0131] In questions  810 (Figure  8 A 3 ), an expert acknowledges if the expert is aware of the music and/or has a recording of the music.  
     [0132] All expert responses to the foregoing questions assign specific values to the music feature vectors. An example of how feature vector values are assigned for music samples is provided in Appendix “A”.  
     [0133] It is noteworthy that the questions in FIGS.  7 A 1 ,  7 A 2   8 A 1 ,  8 A 2  or  8 A 3  are merely illustrative and do not limit the scope of the invention. The number and format of the questions as presented to music listeners or expert listeners may be different than what is shown in FIGS.  7 A 1 ,  7 A 2 ,  8 A 1 ,  8 A 2  or  8 A 3 .  
     [0134] Referring back to FIG. 5A, in step S 501 C, explicit “pairwise” questions are provided to expert music listeners. FIG. 7B shows an example of questions  701  that may be asked. Expert music listeners are provided with a pair of music samples and experts rate the similarity of the samples. Although music is provided in pairs for evaluation, the invention is not limited to providing music samples in pairs. Various other presentation techniques may be used, for example, music samples may be provided as a group of three, and so forth.  
     [0135] It is noteworthy that the invention is not limited to the steps of FIG. 5A for collecting data that describe music attributes. Various other methods may be used, as described below:  
     [0136] Data may be collected as DSP data  403 B using DSEP techniques. DSP techniques includes analyzing digitized audio files containing music into a set of feature vectors which can be used to characterize and compare music. Thus, an audio file for any music is transformed into a set of numbers (feature vectors) which describes the qualities of the music. These numbers are constructed so that they represent the important or relevant features.  
     [0137] Radio logging is another method for collecting data that can describe music. Data stored via radio logging is stored as radio log data  403 B. Radio stations play sets of coherent music and avoid playing music that is likely to unpleasantly surprise their listeners. Thus, radio station play lists provide an implicit measure of similarity based upon the assumption that music played within the same set are likely to have common features. By collecting radio station play lists co-occurrence of music in play lists may be used as a measure of similarity, similar to explicit pairwise data  403 A.  
     [0138] One approach would be to measure the conditional probability of playing music B within a pre-defined time interval after music A has been played. Music with a higher conditional probability is assumed to be more similar. A second approach would be to construct the entire conditional probability distribution over time for each pair of (songs. For example, construct the distribution of time until music B is played, given that Music A has already been played. These entire distributions could then be compared by using a Kullback-Leibler metric as described in “Elements of Information Theory” by T. M. Cover and A. T. Joy. (1991), published by John Wiley &amp; Songs Inc., and incorporated herein by reference.  
     [0139] Internet harvesting may be also used to collect Internet harvested or “Spider data”  403 E. Spiders are well known and collect data of users that browse the Internet. A similar strategy to that of radio logging can be applied for Internet harvesting. Co-occurrence analysis can be carried out on a plurality of web pages. One approach would involve computing the frequency of co-occurrence of artist names on a large sample of web pages. Those artist with higher frequencies of co-occurrence are more likely to have features in common than artists with lower frequencies of co-occurrence. A similar analysis can be conducted for music titles, for albums and music labels etc.  
     [0140] Questionnaire Development:  
     [0141] The questions in steps S 501 A, S 5 O 1 B and S 501 C are designed to achieve accurate ratings for music samples. There are numerous ways in which a question regarding a music sample may be asked to evoke plural responses from music listeners. For example, if the level of “Happiness” after listening to a piece of music is to be determined, then questions may be phrased as follows:  
     [0142] “Rate the song for Sadness - - - Happiness Rate the song if it is Not Happy - - - Happy Strongly Disagree - - - Strongly Agree that the song is Happy” 
     [0143] Each method of asking questions may evoke similar or dissimilar results from music listeners and/or experts. The present invention evaluates questions for form and content to obtain responses that are accurate and can be used efficiently in rating music.  
     [0144]FIG. 5B is flow diagram of the methodology used for evaluating questions, prior to presenting the questions to listeners in steps S 501 A, S 501 B and S 501 C (FIG. 5A).  
     [0145] In step S 5001 , a basic set of questions is developed to ascertain predefined music attributes. For example, as shown above, a basic set of questions is designed with the intent to determine the degree of “happiness” that may be provided to a listener by a piece of music.  
     [0146] In step S 5002 , plural sets of questions are developed based upon the basic question set in step S 5001 . For example, as shown above a plural set of questions to determine the degree of “happiness” evoked by a piece of music may be stated as follows:  
     [0147] “Rate the song for Sadness - - - Happiness Rate the song if is Not Happy - - - Happy Strongly Disagree - - - Strongly Agree that the song is Happy” 
     [0148] In step S 5003 , the plural sets of questions are provided to different sets of listeners with music samples. The plural sets of questions are multiple ways to ask a similar question regarding a music sample.  
     [0149] In step S 5004 , plural sets of listeners respond to the plural set of questions after listening to music samples, and the answers to the questions are evaluated. Questions may be evaluated for plural criteria as described below. A questionnaire that produces optimum and accurate results is chosen for collecting data in steps S 501 A-C (FIG. 5A).  
     [0150] Examples of some of the techniques to filter out inaccurate questions are provided as follows:  
     [0151] (a) Consensus: Questions that produce a lack of consensus between music listener ratings are generally inaccurate and hence are rejected. Consensus in ratings may be measured in plural ways, for example:  
     [0152] Consensus( i )=−1*[Mean(music)(Std Dev (listener)((question (i))] 
     [0153] Consensus (i) is the measured consensus value for an ith question;  
     [0154] Std Dev(listener)(question (i)) is the standard deviation of the ratings for each music sample based upon question (i), for example if five listeners have rated a music sample for a particular attribute and the rating values are R 1 , R 2 , R 3 , R 4  and R 5 , then the Standard deviation of R 1 , R 2 , R 3 , R 4  and R 5  is labeled as Std Dev (listener)(question (i)). Standard deviation of ratings for different music samples for a specific question is calculated and may be designated as STD 1 , STD 2 , STD 3 , . . . STDn, where n is the nth question; and  
     [0155] Mean (Music)(Std Dev(listener)(question (i))is the mean of STD 1  . . . STDn.  
     [0156] Multiplying by a negative number (for example −1 as shown above), reverse orders the statistical values since low standard deviation values correspond to high levels of consensus among music listener ratings.  
     [0157] (b) Discrimination ability: Questions are evaluated such that they allow discrimination in music listener ratings for specific music samples. Questions that do not allow discrimination between samples are rejected. Discrimination may be measured as follows:  
     [0158] Discrimination (i)=Std Dev (music) (Mean (listener) (question (i))) where  
     [0159] Mean (listener)(question(i))is calculated as follows: if a music sample 1 has ratings R 1 , R 2 , R 3 , R 4  and R 5  from five different listeners, then the Mean for the music sample is calculated by (R 1 +R 2 +R 3 +R 4 +R 5 )/5. This mean may be designated as M 1 . Mean for other music samples are also calculated and may be designated as M 2  . . . Mn, where n is the nth sample. Mean (listener)(question(i))) is the mean of (M 1 +M 2  + - - - Mn)/n; and  
     [0160] Std Dev (music) (Mean (listener)(question (i))) is the standard deviation of M 1 , M 2 , M 3 , M 4  and M 5 . Questions with low standard deviation values do not discriminate between music samples. In contrast, questions with high standard deviation values discriminate between music samples. These latter questions (with high standard deviation values) are more informative compared to the questions with low standard deviation values.  
     [0161] (c) Model Based Variance: The usefulness of questions can also be evaluated by examining the contribution of each question within the context of a pre-defined model. One such model is derived by using dimensional reduction techniques such as Principal Components Analysis (“PCA”). Details of the foregoing techniques are provided in “Multivariate Analysis, Methods and Applications” by William R. Dillon &amp; Matthew Goldstein (1984), published by John Wiley &amp; Sons, and in “Multivariate Observations” by G. A. F. Seber, ( 1984 ), published by, John Wiley &amp; Sons, both of which are incorporated herein by reference.  
     [0162] In this technique, a matrix of questions is created. The matrix can be considered as describing each piece of music as a vector in a “question space”, defined by the question matrix. For example, a piece of music, e.g., Sample 1, may be described by average listener responses to a set of questions. Average listener responses may be represented as a vector corresponding to a single column of a matrix (M 1 ), where M 1  includes music samples as columns and listener responses as rows. Thus an ijth entry in M 1  is the average response on the ith question for the jth music sample. Hence, matrix M 1  can be described as a q×s matrix, where q is the number of questions and s is the number of music samples. Hence every music sample is represented as vector in the question space defined by average listener responses.  
     [0163] PCA also derives a rotation matrix (RM) which has dimensions q×q, where q is the number of questions used and is same as the row dimension of M 1 . RM has the following properties: (1) dimensions (or matrix entries) in FM are orthogonal, so that the matrix entries do not overlap in representing information about music samples, and 2) the dimensions or basis vectors represented as RM entries are arranged based upon the amount of variance caused by the questions in the question space.  
     [0164] Matrix entries in the RM show each question&#39;s contribution to the variance in average listener responses. Questions that substantially contribute to the variance across music samples are desirable and are retained whereas questions that do not may be rejected.  
     [0165] (d) Rejected questions are questions that, when excluded produce least deterioration in a similarity model. Excluding certain set of questions for collecting data and as discussed below in step S 505 , evaluating the similarity model based on the included set of questions provides the relative contribution of the questions.  
     [0166] In step S 5005 , questions that provide accurate results in the modeling process are retained and then eventually provided to listeners in steps S 501 A, S 501 B and S 50 LC (FIG. 5A).  
     [0167] Establishing Feature Vectors:  
     [0168] In step S 502 , listeners respond to plural questions from steps S 501 A-S 501 C.  
     [0169] In step S 503 , plural listener responses to the plural questions are collected. The various questions answered by music listeners or by music experts provide values to a plurality of feature vectors that are used to define music attributes, and the feature vectors are then used to compare and search music based upon music content. As discussed below, various feature vectors are used to create a plurality of music spaces that define the location of a piece of music in a specific music space.  
     [0170] Appendix “A” provides an example of numerous feature vectors that may be used to define music samples with feature vectors.  
     [0171] Examples of certain vectors to define music attributes are provided below:  
     [0172] (a) Emotional quality vector: This vector is based upon the emotional response derived from a listener by a particular piece of music, for example, whether music samples are:  
     [0173] Intense  
     [0174] Sad  
     [0175] Mellow  
     [0176] Romantic  
     [0177] Broken-hearted  
     [0178] Aggressive  
     [0179] Upbeat  
     [0180] Emotional quality vector values are based upon listener response to questions  700 B (FIGS.  7 A 1  and  7 A 2 ). The foregoing examples and the questions in  700 B are merely illustrative and are not intended to limit the scope of the invention. As discussed below, emotional quality vector is used to define an emotional quality space.  
     [0181] (b) Vocal quality vector: A vocal quality vector is based on the vocal qualities of a particular piece of music, for example, whether a music sample has a:  
     [0182] Sexy voice  
     [0183] Smooth voice  
     [0184] Powerful voice  
     [0185] Great voice  
     [0186] Soulful voice  
     [0187] Vocal quality vector values are based upon listener response to questions  700 C, in FIG. 7A 2 . The foregoing examples and the questions in  700 C are merely illustrative and are not intended to limit the scope of the invention. As discussed below, vocal quality vector is used to define a vocal quality space.  
     [0188] (c) Sound quality vector: A vector based on the vocal quality of a particular music sample, for example, whether a music sample has a:  
     [0189] Strong beat  
     [0190] Is Simple  
     [0191] Has a good Groove  
     [0192] Is Fast  
     [0193] Is speech like  
     [0194] Emphasizes a melody  
     [0195] Sound quality vector values are based upon listener response to questions  700 A (FIG. 7A 1 ). The foregoing examples and the questions in  700 A are merely illustrative and are not intended to limit the scope of the invention. As discussed below, sound quality vector is used to define a sound quality space.  
     [0196] (d) Situational vector: A vector that establishes the optimum situation in which a particular piece of music may be used, for example, whether a music sample is:  
     [0197] Good for a workout  
     [0198] Good for a shopping mall  
     [0199] Good for a dinner party  
     [0200] Good for a dance party  
     [0201] Good for slow dancing  
     [0202] Good for studying  
     [0203] Good for driving  
     [0204] Good for relaxing  
     [0205] Vocal quality vector values are based upon listener response to questions  700 D (FIG. 7A 2 ). The foregoing examples and the questions in  700 D are merely illustrative and are not intended to limit the scope of the invention. As discussed below, situational quality vector is used to define a sound quality space.  
     [0206] (e) Genre vector: A vector that determines the genre or a genre combination of a particular piece of music, for example, whether a music sample belongs to the following genres or a combination of the following genres:  
     [0207] Alternative  
     [0208] Blues  
     [0209] Country  
     [0210] Electronic/Dance  
     [0211] Folk  
     [0212] Gospel  
     [0213] Jazz  
     [0214] Latin  
     [0215] New Age  
     [0216] R&amp;B/Soul  
     [0217] Rap/Hip-Hop  
     [0218] Reggae  
     [0219] Rock  
     [0220] Genre vector values are based upon listener response to questions in  801  and  802  (FIGS.  8 A 1 - 8 A 2 ). The foregoing examples and the questions in  801  and  802  are merely illustrative and are not intended to limit the scope of the invention. As discussed below, genre vector is used to define a genre space.  
     [0221] (f) Ensemble Vector: A vector based upon music&#39;s ensemble, for example, if a music sample includes:  
     [0222] Female solo  
     [0223] Male solo  
     [0224] Female duet  
     [0225] Male duet  
     [0226] Mixed duet  
     [0227] Female group  
     [0228] Male group  
     [0229] Instrumental  
     [0230] Ensemble vector values are based upon listener response to questions in  803  and  804  (FIG. 8A 2 ). The foregoing examples and the questions in  803  and  804  are merely illustrative and are not intended to limit the scope of the invention. As discussed below, ensemble vector is used to define an ensemble space.  
     [0231] (g) Instrument vector: An instrument vector is based upon the level of importance of a particular instrument(s), for example, if a music sample includes an:  
     [0232] Acoustic guitar  
     [0233] Electric guitar  
     [0234] Bass  
     [0235] Drums  
     [0236] Harmonica  
     [0237] Organ  
     [0238] Piano  
     [0239] Synthesizer  
     [0240] Horn  
     [0241] Saxophone  
     [0242] Strings  
     [0243] Instrument vector values are based upon listener response to questions in  806 ,  807  and  808  (FIG. 8A: 2 ). The foregoing examples and the questions in  806 , 807  and :B 08  are merely illustrative and are not intended to limit the scope of the invention. As discussed below, instrument vector is used to define an instrument space.  
     [0244] As discussed above, DSP techniques may also be used to acquire DSP data  403 B that can be used to construct feature vectors. One such DSP technique for constructing a DSP feature vector is as follows.  
     [0245] (a) Extract information from a given audio file. The well-known .wav format or any other format may be used to represent an audio file.  
     [0246] (b) Extracted information is represented as a long vector of numbers, which correspond, to the amplitude of an audio signal as a function of time. This vector may be transformed into a spectrogram, which represents the audio file as a time-frequency matrix. Each row of the spectrogram represents instantaneous energy (as a function of time) within a particular frequency band. Each column of the spectrogram represents the instantaneous energy at a particular point in time across a set of feature bands. For a typical 30 second segment of a song, sampled at CD quality (44.1 KHz) the spectrogram may be large and cumbersome. To simplify computation and reduce processing time, the spectrogram may be sub-sampled. The reduced spectrogram is then processed.  
     [0247] (c) For each frequency band the process computes the Fourier transform which characterizes the periodic structure within each band. The process keeps the magnitude of the Fourier transform and ignores the phases of each periodic component.  
     [0248] (d) Construct a representation of the periodic structure of a piece of music within each of set of frequency bands. This set of numbers can be characterized as a feature vector. With a metric (e.g. a Euclidean metric) these feature vectors may be compared, so that vectors with smaller distances are closer to each other than vectors that are farther apart.  
     [0249] In step S 503 , listener responses are stored in R&amp;D database  405 , and in step S 504 , acquired data  404  collected in step S 502  is transferred to Modeling Module  406 .  
     [0250] Modeling of Acquired data:  
     [0251] In step S 505 , Modeling Module  406  analyzes acquired data  404  and also performs a similarity computation. The similarity computation determines the optimum function that can represent similarity between different music samples, based upon defined music attributes (i.e. feature vector values).  
     [0252] For example, assume that a first music sample way be defined by a vector VA, where VA=(V 1 , V 2  . . . Vn) and V 1 ,V 2  . . . Vn are music attributes based upon data collected above. A second music sample may be defined by a vector VB, where VB=[V 1 ′, V 2 ′ . . . Vn′], and V 1 ′, V 2 ′ . . . Vn′ are music attributes based upon data collected above. Modeling Module  406  compares vectors VA and VB using a similarity function F(VA,VB). The method for calculating F(VA,VB) is described below. The foregoing example is merely to illustrate the functionality of Modeling Module  406  and does not limit the invention.  
     [0253] The discussion below illustrates the various steps performed by Modeling Module  406 .  
     [0254] A feature vector V for a set of music samples may be V=(V 1 , V 2 , V 3  . . . Vn), where V 1  . . . Vn values are based upon plural responses received in steps S 501 A and S 50 OIB. A matrix S can be defined as a n×p matrix to represent vector V, where p is the number of music samples in the set, hence, S=[V 1 |V 2 |V 3 | . . . VN].  
     [0255] For computational ease, matrix S can be reduced to a smaller matrix S′, where S′ is a m×p where m&lt;n. Hence S represents a set of p music samples in a n dimensional space, and S′ represents the same set in m dimensional space, where m&lt;n.  
     [0256] To create matrix S′, various dimensional reduction techniques such as Principal Component Analysis, Multi-dimensional Scaling or related techniques may be used. Such techniques are described in “Multivariate Observations” by G. A. F. Seber, ( 1984 ), referenced above. It is noteworthy that S′ is created so that fewer vectors are used for performing a similarity analysis as described below, without losing essential information from matrix S.  
     [0257] Subsets of each vector V may also include vectors that are defined in specific music spaces. For example vector VI can include vectors Vg, Ve, Vt, Vv and Vi, where Vg represents a piece of music sample in a genre space,, Ve represents a piece of music in a emotional quality space, Vt represents a piece of music in a tempo space, Vv represents a piece of music in a voice quality space, and Vi represents a piece of music in a instrument space. Vg, Ve, Vt, Vv and Vi may be represented as follows:  
     [0258] Vg=(Vg 1 , . . . Vga)  
     [0259] Ve=(Ve 1 , Ve 2  . . . Veb)  
     [0260] Vt=(Vt 1 , Vt 2  . . . Vtc)  
     [0261] Vv=(Vv 1 , Vv 2  . . . Vvd)  
     [0262] Vi=(Vi 1 , Vi 2 , . . . Vie)  
     [0263] Also, based upon data collected in step S 501 C, a representative matrix S 1  is created that includes perceived similarity data of plural music pairs, illustrated for convenience as pair i,j. Generally, matrix SI shall include ratings that illustrate similarity and/or dissimilarity between a pair of music.  
     [0264] Furthermore, Modeling Module 406 calculates a distance matrix D that estimates the distances between pairs of music samples in matrix Si. Distances between pairs of music samples may be calculated in more than one music space. One method of calculating distance is the Euclidean distance, illustrated as Dij, where Dij= 
       SQRT [Vi 1 −Vj 1)^ 2+( Vi 2 −Vj 2)^ 2 - - - ( Vik−Vjk )^ 2] 
     [0265] where Vi 1 , Vi 2  . . . Vik are feature vector values for the ith music sample, and Vj 1 , Vj 2  - - - Vjk are feature vector values for the jth music sample. The feature vector value specifies the location of the music sample in a particular space. It is noteworthy that Dij is not limited to Euclidean distance, and that any mathematical technique that can illustrate the distance between the vectors can be used.  
     [0266] Distance matrix Dij is created for plural music spaces, and may be illustrated as Dg (distance between music sample i and j in the genre space), De(distance between music sample i and j in the emotional quality space), Dv(distance between music sample i and j in the vocal quality space), Dt (distance between music sample i and j in the tempo space) and Di (distance between music sample i and j in the instrument space). The methodology of creating individual and combined spaces is described below.  
     [0267] A function Fij represents the distances between music sample i and j and may be illustrated as:  
     [0268] WgDg+WeDe+WvDv+WtDt+WiDi, where Wg, We, Wv, Wt and Wi are individual weights allocated to individual music spaces. The plural weights Wg, We, Wv, Wt and Wi are calculated such that S 1  and Fij are at a minimum distance from each other. Essentially a function F is determined to model the observed or “true” similarity between music represented in the matrix S 1 . Thus the derived function F may be applied generally to all pairs of music I and j, not just those reflected in the matrix S 1 .  
     [0269] Function Fij may be fit by using linear regression or by nonlinear regression techniques as disclosed in “ Generalized Linear Models ” by McCullagh &amp; Nelder, and  Generalized Additive Models  by Hastie &amp; Tibshirani, both published by Chapman and Hall, and incorporated herein by reference in their entirety.  
     [0270] Other tools may be used to compute the weights shown above and fit function Fij, as follows:  
     [0271] (a) Bayesian estimation techniques as disclosed in  
     [0272] “An Introduction to Bayesian Statistical Decision Process” by Bruce W. Morgan, (1968) published by Prentice-Hall, Inc., and “Learning Bayesian Networks” by HeckRerman D &amp; D. Geiger, (1994), may be used and are incorporated herein by reference in their entirety. Essentially, BayesieLn techniques choose a model distribution for S 1  entrees and then find the foregoing weights for Fij that maximize an appropriate likelihood function. For example, if the distribution of S 1  entries is a Gaussian distribution, then the likelihood function is a function that would maximize the probability of the observed values of S 1  with the given parameters of the Gaussian distribution and the weights used to combine spaces.  
     [0273] Standard Maximum Likelihood Estimation techniques are disclosed in “Elements of Statistical Computing” by R. A. Thisted (1988), published by Chapman &amp; Hall) and in “Bayesian Data Analysis” by A. Gelman, J. Carlin, H. S. Stern &amp; D. B. Rubin (1995), published by CRC Press, may be used for determining the foregoing weights, and both are incorporated herein by reference in their entirety.  
     [0274] (b) Neural Network techniques as disclosed in “Neural  
     [0275] Networks, a Comprehensive Foundation”, by Haykin, S. (1994), published by Macmillan, and incorporated herein by reference in their entirety may also be used to calculate the foregoing weights and model similarity between S 1  and Fij, and between other music samples.  
     [0276] Neural networks are nonlinear optimization and function-learning algorithms and may be used to model the similarity between S 1  and Fij. A simple 3 layer feed forward reverse feed network architecture as shown in FIG. 5C 1  may be used.  
     [0277] Input bottom layer is divided into 2 parts,  500 C 1  and  500 C 2 , each corresponding to feature vectors of the music samples to be compared (for example, songs A and B). A group of network layers  500 C 4  are fully interconnected (e.g., every node in the input layer ( 500 C 1  and  500 C 2 ) is connected by a weight to every node in the middle layer( 500 C 4 ). The output consists of a single node which reads out the similarity  500 C 3  between the 2 input songs, A and B.  
     [0278] The neural network  500 C 5  can be trained with a random set of the pairs of music for which similarity data is available (for example in matrix S 1 ). FIG. 5C 2  shows the process steps used for training network  500 C 5 :  
     [0279] Step 1. Select a pair of music samples A and B.  
     [0280] Step 2. Set the input layer values to the feature vectors of music samples A and B.  
     [0281] Step 3. Transfer input layer values forward through the network to the output layer (output node,  500 C 3 ).  
     [0282] Step 4. Compare the difference between the computed similarity value,  500 C 3  and the actual value (from matrix Si).  
     [0283] Step 5. Reverse feed the difference (error signal) through the network  500 C 5  and adjust weights accordingly.  
     [0284] Step 6. Repeat until the network has achieved the desired performance.  
     [0285] (c) Classification Trees: Techniques disclosed in “Classification and Regression Trees”, by Brieman, J. H. Friedman, R. A. Olshen &amp; C. J. Stone (1984), published by Wadsworth, Belmont Calif., may also be used to calculate the foregoing weights and perform the similarity analysis, and is incorporated herein by reference in their entirety. Classification trees define a hierarchical or recursive partition of a set based on the values of a set of variables. In the present case, the variables are the elements of plural feature vectors. A decision tree is a procedure for classifying music into categories according to their feature vector values. Expert pairwise data  403 A may be used to define a satisfactory decision tree and then the tree may be applied to a larger set of music. This method partitions music samples into mutually exclusive categories, wherein music samples within each category are considered similar.  
     [0286] (d) Hierarchical Clustering: Techniques disclosed in “Multivariate Analysis: Methods and Applications” by William R. Dillon &amp; Matthew Goldstein (1984), published by John Wiley &amp; Sons; and “Multivariate Observations” by G. A. F. Seber (1984),published by John Wiley &amp; Sons, and both are incorporated herein by reference in their entirety, may also be used to calculate the foregoing weights and perform the similarity analysis. Hierarchical clustering methods produce a hierarchical tree structure for a set of data. These methods may be used to partition a music set into a set of similar clusters as follows:  
     [0287] A hierarchical clustering algorithm assigns music samples to a cluster, wherein the cluster is based on the similarity of the feature vectors of plural music samples. Each cluster may belong to a higher level cluster, so that the top-level or root cluster contains all music samples. Thus music samples are arranged in a hierarchy of clusters, each music sample being most similar to those songs in its most “local” or lowest level cluster and successively less similar to songs which belong to only the same higher level clusters.  
     [0288] A function F may assign high similarity scores to pairs of music samples based on the lowest level of the tree structure that samples share in common. For example, music samples, which belong to the same lowest-level cluster, are very similar, whereas songs which have no cluster in common except the root cluster are most dissimilar.  
     [0289] (b) Fuzzy Queries: Techniques provided in “An  
     [0290] Introduction to Fuzzy Logic Applications in Intelligent Systems” by R. R. Yager &amp; Lotfi A. Zadeh. (1992), published by Kluwer Academic Publishers, and incorporated herein by reference in their entirety, may also be used to calculate the foregoing weights and perform the similarity analysis. Fuzzy techniques essentially place graded or “soft” constraints on matching criteria rather than on “hard” or Boolean constraints. A fuzzy approach is essentially one in which the degree to which one piece of music is similar to another piece of music follows a continuous or graded function.  
     [0291] Once the weights Wg, We, Wv, Wt and Wi are determined and function Fij is fit, the data can be used for comparing any pair of music. It is noteworthy that the weights can be changed dynamically if listener ratings for specific music sample change over time. Further, weights can be varied based upon individual listeners or a group of listeners. Weights can be specified for plural spaces. The modeled attribute data is stored and can be searched to compare music based upon pre-defined attributes.  
     [0292]FIG. 5C 3  is a flow diagram showing various computerized process steps performed by Modeling Module  406  to process listener data and perform a similarity analysis.  
     [0293] In step S 505 A, listener response data is obtained from R&amp;D database  405 .  
     [0294] In step S 505 B, a similarity matrix (Si) is created. S 1  is based upon data collected in step S 501 C (FIG. 5A). Matrix S 1  includes perceived similarity data of a music pair, illustrated for convenience as pair i,j. Generally, matrix S 1  includes ratings that illustrate similarity and/or dissimilarity between a pair of songs.  
     [0295] In step S 505 C, Modeling Module  406  creates a matrix S that includes plural feature vector values as shown above. Thereafter, Modeling Module  406  performs a dimensional reduction step so as to reduce the number of dimensions in matrix S. Assume that a feature vector V for a set of music samples=(V 1 ,V 2 , V 3  . . . Vn), where Vi . . . VrL are based upon plural responses received in steps S 501 A and S 501 B. A matrix S can be defined as: S=[V 1 |V 2 |V 3 |. . . VN], where S, is a n&#39;p matrix, where p is the number of music samples in the set.  
     [0296] For computational ease, matrix S can be reduced to a smaller matrix S′, where S′ is a m×p matrix, where m&lt;p. Hence S represents a set of p music samples in a n dimensional space and S′ represents the same set in m dimensional space, where m&lt;n. Various dimensional reduction techniques may be used, as described above.  
     [0297] In step S 505 D, Modeling Module  406  creates various subspaces, as described below. Music subspaces are based upon feature vector values. For example a feature vector V for a set of music samples is given by V=(V 1 ,V 2 , V 3  . . . Vn). Subsets of each vector V also include vectors that are defined in specific music spaces. For example vector VI can include vectors Vg, Ve, Vt, Vv and Vi, where Vg represents a piece of music in a genre space, Ve represents a piece of music in a emotional quality space, Vt represents a piece of music in a tempo space, Vv represents a piece of music in a voice quality space and Vi represents a piece of music in a instrument space. Vg, Ve, Vt, Vv and Vi may be represented as follows:  
     [0298] Vg (V= . . . Vga)  
     [0299] Ve=(Ve 1 , Ve 2  . . . Veb)  
     [0300] Vt=(Vt 1 , Vt 2  . . .Vtc)  
     [0301] Vv=(Vv 1 , Vv 2  - - - Vvd)  
     [0302] Vi=(Vil, Vi 2 , . . . Vie)  
     [0303] In step S 505 E, the process combines plural music spaces, i.e. genre space, vocal quality space, emotion space, sound quality space, instrument space and global space to fit the similarity matrix S 1 . A distance matrix D is calculated between the pair of songs in matrix S 1 . Distance between i and j piece of music may be calculated in more than one music space. One method of calculating distance is the Euclidean distance, illustrated as Dij, where Dij= 
       SQRT ( Vi 1 −Vj 1)^ 2+( Vi 2 −Vj 2)^ 2 - - -( Vik−Vjk )^ 2  
     [0304] where Vi 1 , Vi 2  - - - Vik are feature vector values for the ith song, and specifies the location of a music sample in a particular space.  
     [0305] Distance matrix Dij is created for plural music spaces, and may be illustrated as Dg (Dg for genre space), De(for emotion space), Dv(for vocal space), Dt (for tempo space) and Di(for instrument space).  
     [0306] As discussed above, a music pair may be represented by the function Fij where Fij= 
     [0307] WgDg+WeDe+WvDv+WtDt+WiDi, where Wg, We, Wv, Wt and Wi are individual weights allocated to individual music spaces. The plural weights Wg, We, Wv, Wt and Wi are calculated such that S 1  and Fi are at a minimum distance from each other. The discussion above describes how the plural weights may be calculated.  
     [0308] It is noteworthy that the combined music space can be created real time based upon listener request and preferences.  
     [0309] Production Database:  
     [0310] In step S 506 , based upon the modeled data, production database  407  is created. The production database includes set of weights calculated in step S 505 . A sample entry in the production database  407  may be stored as follows:  
                                  Data Block I.                                                         song_id   v1   v2   v3   v4   v5   v6   v7   v8   v9   v10       v11   v12   v13   v14   v15   v16   v17   v18   v19   v20   v21       v22   v23   v24   v25   v26   v27   v28   v29   v30   v31   v32       v33   v34   v35   v36   v37   v38   v39   v40   v41   v42   v43       v44   v45   v46   v47   v48   v49   v50   v51   v52   v53   v54                     release_year                     Data Block II.                                         6319   0.663043   1.000000   NULL 0.000000   1.000000   1.000000               1.000000   0.000000   0.000000   0.000000   0.000000           0.000000   0.000000   0.000000   0.000000   0.000000           0.000000   0.000000   0.000000   0.000000   0.000000           0.000000   0.000000   0.000000   0.000000   0.000000           1.000000   0.348485   0.560606   0.424242   0.409091           0.560606   0.530303   0.636364   0.590909   0.136364           0.166667   0.242424   0.181818   0.196970   −0.080946           0.045888   −0.132495   0.029958   0.009163   0.008496   —           0.000661   0.655467   1.317940   0.604017   0.000000           0.000000   0.000000   0.000000   1994       6316   0.315217   1.000000   NULL   0.000000   1.000000           1.000000   1.000000   0.000000   0.000000   0.000000           1.000000   0.000000   0.000000   0.000000   0.000000           0.000000   0.000000   0.000000   0.000000   0.000000           0.000000   0.000000   0.000000   0.000000   0.000000           0.000000   1.000000   0.370370   0.425926   0.444444           0.296296   0.351852   0.444444   0.518519   0.481481           0.314815   0.259259   0.333333   0.370370   0.351852           0.175593   0.099421   0.026434   0.028079   −0.041860   —           0.033818   0.028811   1.380721   0.924552   0.149940           0.000000   0.000000   0.000000   0.000000   1990                  
 
     [0311] Block I specifies column names for feature vectors, while Block II includes the actual values corresponding to the Block I column entries. For illustration purposes, the first entry, song_id, is a unique identifier for each piece of music. Entries v 1 -v 54  refer to specific attributes of each piece of music. The last entry, release_year, refers to the release year of the song. The following labels are used for v 1 -v 54 :  
                                                   NAME   Column Name                          Tempo   v1           Lead Vocals   v2           Focus Background Vocals   v3           Acoustic Guitar   v4           Electric Guitar   v5           Bass   v6           Drums   v7           Harmonica   v8           Organ   v9           Piano   v10           Synthesizer   v11           Horn   v12           Saxophone   v13           Strings   v14           Alternative   v15           Blues   v16           Country   v17           Electronic/Dance   v18           Folk   v19           Gospel   v20           Jazz   v21           Latin   v22           New Age   v23           R&amp;B/Soul   v24           Rap/Hip-Hop   v25           Reggae   v26           Rock   v27           Smooth Voice   v28           Soulful Voice   v29           Sexy Voice   v30           Great Voice   v31           Powerful Voice   v32           Intense   v33           Upbeat   v34           Aggressive   v35           Relaxing   v36           Mellow   v37           Sad   v38           Romantic   v39           Broken-hearted   v40           Coord1   v41           Coord2   v42           Coord3   v43           Coord4   v44           Coord5   v45           Coord6   v46           Coord7   v47           Coord8   v48           Coord9   v49           Coord10   v50           Parent   v51           Level   v52           ClustVal   v53           ClustNSong   v54           Year   v55                      
 
     [0312] The foregoing example is merely one way to store information in production database  407 ; other formats may be used to develop production database  407  within the spirit of the present invention. The foregoing example should be interpreted with respect to Appendix “A”.  
     [0313] In step S 507 , the process evaluates the similarity model created in step S 505 . Generally, a focus group of music listeners and experts will verify the similarity results by listening to music samples. Explicit feedback from users of the system is also used to modify the similarity model and to identify songs with poor similarity matches. All acceptable similarity matches are retained in production database  407 .  
     [0314] In step S 508 , listeners and experts reevaluate all music samples that are rejected in step S 507 , and similarity data based upon listener response, similar to those in FIG. 7B, is obtained.  
     [0315] In step S 509 , music samples compared in step S 508  are stored as matched sets in similarity database  407 A. It is noteworthy that the invention is not limited to a separate similarity database. Music sets obtained after step S 508  may be stored in the production database  407 , without limiting the scope of the invention.  
     [0316] Music Space:  
     [0317] As discussed above, one of the shortcomings of the conventional music search systems is that music cannot be searched by music content. The reason for this shortcoming is that music is an emotional experience that is difficult to describe by plain text. However, the present system solves this problem by providing plural music spaces that can locate music by content. As shown above, various aspects and perceptual qualities of music are described by a plurality of feature vector values. Most of the feature vectors are defined by data acquired in process steps shown in FIG. 5A.  
     [0318] Based upon feature vectors, a multidimensional music space is created. In the music space, a piece of music can be located based upon the co-ordinates that define specific music attributes. As discussed above, since music has plural facets and attributes, the plurality of feature vectors are divided into plural categories, for example, emotional quality vector, vocal quality vector, genre quality vector, ensemble vector and situational vector. Hence a plurality of music spaces may be used to define and locate music based upon music content defined by plural feature vectors. Examples of such music spaces are genre space, emotional quality space, vocal quality space, and tempo space etc., as discussed below.  
     [0319] A generic definition of music space for the purpose of this invention can be described as follows:  
     [0320] Let X be a set containing elements {x 1 , x 2 , . . . }. Let a f(xi,xj) be a real-valued function (where xi, xj are included in set X) which satisfies the following rules for any xi,xj, xk in X:  
     [0321] 1. f(xi,xj)&gt;=0  
     [0322] 2. f(xi,xj)=0 if and only if xi=xj  
     [0323] 3. f(xi,xj)=f(xj,xi)  
     [0324] 4. f(xi,xk)&lt;=f(xi,xj)+f(xj,xk) [The Triangle Inequality] 
     [0325] Then the joint pair (X,f) is called a metric space and f is called the metric. In the present invention, a music space is a metric space defined by a given set of feature vectors).  
     [0326] Also, a combined music space is created based upon plural vectors such that a piece of music can be located within the combined music space with defined co-ordinates. The combined music space is created by providing certain weights to plural feature vectors. The weights for individual feature vectors may be calculated in a plurality of ways, as discussed above. Furthermore, the weights may be calculated based upon listener preferences. The combined music space is created based upon a listener&#39;s request and hence is dynamic in nature.  
     [0327] Creating a Genre Space  
     [0328] According to another aspect of the present invention, a genre space is created based upon data collected and modeled in FIG. 5A. The genre space is defined by a set of genre vectors, where the vector values are obtained from expert data collected in step S 501 A, according to questions  801  (FIG. 8A 1 ). Based upon genre vector values, the location a music piece may be obtained in the genre space. The distance between different music samples within the genre space indicates the similarity between the music samples with respect to genre.  
     Creating a Voice Quality and Emotional Quality Space  
     [0329] According to another aspect of the present invention, a voice quality and emotional quality space is created based upon data collected and modeled in FIG. 5 and listener responses to questions in  700 C and  700 B (FIGS.  7 A 1  and  7 A 2 ), respectively.  
     [0330] The voice quality space determines the location of a piece of music in the vocal quality space. The voice quality space is defined by a set of feature vectors, where the feature vector values depend on listener response to questions in  700 C (FIG. 7A 2 ). Based upon voice quality vector values the location of a music piece may be obtained in the voice quality vector space. The distance between different music samples within the voice quality space indicates the similarity between the music samples with respect to voice quality.  
     [0331] The emotional quality space measures the emotional reaction to a particular piece of music. The emotional quality space is defined by a set of feature vectors (emotional quality vector), where the feature vector values are based upon listener responses to questions in  700 B (FIGS.  7 A 1  and  7 A 2 ). Based upon emotional quality vector values, a music piece may be located in the emotional quality space. The distance between different music samples within the emotional quality space indicates the similarity between the music samples with respect to emotional reaction evoked by a piece of music.  
     [0332] Creating a Tempo Space:  
     [0333] A “tempo” space is created by feature vector(s) whose value depends upon the number of beat per minute and/or second. The number of beats may be obtained by collecting expert data or by using an algorithm(s). Details of such algorithms to collect tempo data may be obtained from “Tempo and beat analysis of acoustic music signals”, by Eric D. Scheirer, Machine Group listing, E-15-401D MIT media Laboratory, Cambridge, Mass. 02139)(December 1996), incorporated herein by reference.  
     [0334] Creating a Similarity Space  
     [0335] Details of creating a similarity space are provided above in Step S 505  of FIG. 5A.  
     [0336] Combining Music Spaces  
     [0337] As described above, based upon the plural feature vectors, described above, every piece of sampled music is located in a genre space, voice quality space, emotional quality space, tempo space and a generic similarity space.  
     [0338] A combined music space is created real time based upon a listener&#39;s request for music. A piece of music has a location in the genre, vocal quality, emotional quality, and tempo space etc. Every space, including genre, voice quality, emotional quality, and tempo space is allocated a certain weight, wherein the value of the weight depends upon a user&#39;s preference and may be changed. A function defined by a weighted average of plural vectors provides a combined music space and assists in determining similar songs. The combined music space may be changed every time a listener provides a different request. An example of a combined music space that allows content based searching is given below:  
     [0339] Assume that a first music sample has the following locations:  
     [0340] d 1  in the genre space, d 2  in the vocal quality space, d 3  in the emotional quality space, d 4  in the tempo space and d 5  in the similarity space.  
     [0341] The location of first music sample is given by, D, where D is equal to:  
     W1*d1+W2*d2+W3*d3+W4*d4+W5*d5  
     [0342] W 1 , W 2 , W 3 , W 4  and W 5  are weights allocated to different spaces and may be changed. W 1 , W 2 , W 3 , W 4  and W 5  are calculated by a process similar to that of step S 505 . (FIGS.  5 A and  5 C 3 ).  
     [0343] Assume that a second music sample has the following locations:  
     [0344] d 1 ′ in the genre space, d 2 ′ in the vocal quality space, d 3 ′ in the emotional quality space, d 4 ′ in the tempo space and d 5 ′ in the similarity space.  
     [0345] The location of second music sample is given by D′, where D′ is equal to:  
     W1′*d1′+W2′*d2′+W3′*d3′+W4′*d4′+W5′*d5′.  
     [0346] W 1 ′, W 2 ′, W 3 ′, W 4 ′ and W 5 ′ are weights allocated to different spaces and may be changed. Weights W 1 ′, W 2 ′, W 3 ′, W 4 ′ and W 5 ′ are calculated by a process similar to that of step S 505 . (FIGS.  5 A and FIG. 5C 3 ).  
     [0347] Comparing D and D′ compares the first and second music samples to each other. Details of comparing D and D′ are provided above in step S 505  of FIG. 5A.  
     [0348]FIG. 5D shows sample representation of individual spaces, for example, genre space, emotion space, vocal quality space and sound space. FIG. 5D also shows location of music samples A and B with respect to each other in specific spaces. It is noteworthy that FIG. 5I) shows one way presenting individual spaces and is merely illustrative. FIG. 5D does not limit the scope of the invention to the specific examples.  
     [0349] Quality Assurance of the Rating Process  
     [0350] In another embodiment of the present invention, a quality assurance system is provided so that only music listeners that provide accurate and consistent ratings are used for acquiring data in steps S 501 A, S 501 B and S 501 C (FIG. 5A). The system uses plural techniques that evaluate music listener capabilities and consistency, including measuring “typicality”, “reliability” and “discrimination”.  
     [0351] Measuring Typicality:  
     [0352] The premise for measuring typicality is that if listeners provide accurate ratings, then they are more likely to agree with the responses of other music listeners. Prior to measuring typicality, a music listener is calibrated. FIG. 5E shows process steps for calibrating a music listener.  
     [0353] Calibration:  
     [0354] In step S 500 A, a set of music samples with plural questions (“calibration sample”) is provided to a music listener. Music samples with plural questions may be provided on-line via a computer connected to the Internet (Computer X, FIG. 3) or offline via CD&#39;s or audio tapes, etc. Generally, calibration music samples include music that has well known feature vector values or historical responses from other calibrated listeners.  
     [0355] In step S 500 B, a music listener&#39;s responses to the plural questions are collected and stored. FIG. 5F illustrates an example how collected data may be stored. Column  500 AA in FIG. 5F, shows questions 1 to n that are asked for a specific music sample (Music Sample I), column  500 BB shows music listener responses (R1 to Rn) to the questions in  500 AA and historical responses (R1h to Rnh) or range of historical responses are shown in column  500 CC.  
     [0356] Historical standard deviations (σ1h to σnh) of music listeners responses are stored in column  500 DD. For example, σ1 is the standard deviation of the range of historical responses to question 1 for music sample I. FIG. 5F also shows a generic formula that may be used to calculate historical standard deviation values. Standard deviation values may be acquired from Acquired database  404  or R&amp;D database  405 .  
     [0357]FIG. 5F also shows Median values for historical responses stored in column  500 EE. For example, median values for responses to question 1, Sample I, may be based upon M historical responses, stored as R1h1, R1h2, R1h3 - - -R1hn′. The median value R1hmed for question 1 can then be determined. The historical responses are collected according to steps S 501 A, S 501 B and S 501 C (FIG. 5A). The median values R1hmed to Rnhmed, as shown in column  500 EE may be obtained from Acquired database  404  and/or R&amp;D database  405  by determining the median value of M responses for each of the n questions.  
     [0358] Column  500 FF shows the time spent by a listener in listening to a sample and answering a question(s) associated with the sample. Column  500 GG shows the historical time spent by other listeners.  
     [0359] Column  500 HH shows the mean values for the historical responses. For example for question 1, if the historical responses range from R1h1 to R1hn′, then the mean for the response to question is (R1h1+R1h2- - - R1hn′)/n′, and stored as R1hm.  
     [0360] It is noteworthy that FIG. 5F is illustrative and is not intended to limit the invention, as the data may be stored in a plurality of ways.  
     [0361] In step S 500 C, music listener&#39;s responses are compared to historical responses. For example, music listener sample response R1 for question 1, music sample I, is compared with response R1h1. If R1-R1h1 exceeds a value Rth, where Rth is a threshold value, then response R1 is tagged as a “bad” response. Rth is based upon historical responses and is continuously refined as more data is collected from music listeners and experts.  
     [0362] In step S 500 D, the process calculates standard deviation of music listener&#39;s responses. As shown in FIG. 5E, music listener standard deviation is calculated based upon responses R1 to Rn for a specific sample. FIG. 5F provides the formula for calculating the standard deviation.  
     [0363] In step S 500 E, the process compares music listener standard deviation to historical standard deviations. Historical standard deviation may be the mean of σ1h to σnh. For example, if music listener standard deviation is Std(l) and the mean historical standard deviation for questions 1 to n is Std(h), then Std(l) is compared to Std(h) and if the difference is greater or less than a threshold value, then a music listener may need to be trained with respect to music samples, questions and responses. Feedback is provided automatically on-line while the music listener is still listening to a sample.  
     [0364] In step S 500 F, a music listener&#39;s Z score is calculated. Z score for a question i is given by: (Xi-Mean(i))/Std(i), where Xi is the listener response to question i, Mean(i) is the historical mean for question i(column  500 HH, FIG. 5F), STD(i) is the historical standard deviation of question i. For example with respect to FIG. 5E, Z score for the first question (hence i=1) is (,R1-R1hm)/σ1. Z score for each question is calculated and thereafter the process calculates ΣZ i   2 . If Σz i   2  exceeds a defined threshold value, then a music listener&#39;s ratings are questioned and/or tagged. The threshold value is again based upon historical data and may be refined as more data is collected. Z score may also be calculated by using historical median values instead of the mean values shown above ( 500 EE, FIG. 5E)  
     [0365] It is noteworthy that steps S 500 C, S 500 D and S 500 F may all be performed simultaneously or may be performed selectively. For example, only S 500 C or S 500 D or S 500 E or any other combination of the foregoing steps may be performed to adequately calibrate a listener.  
     [0366] Typicality  
     [0367]FIG. 5G shows process steps to evaluate typicality of a music listener&#39;s response(s), after a music listener is calibrated per FIG. 5E.  
     [0368] In step S 500 G, a music listener is provided with more samples and questions regarding the music samples. Again the samples may be provided on-line via the Internet(or a private network), CDs or audio tapes, etc.  
     [0369] In step S 500 H, the process stores listener responses. Although listener responses are stored, some of the process steps shown below take place real time while a listener is listening to music and answering questions. FIG. 5F illustrates stored listener responses and historical values.  
     [0370] In step S 500 I, a music space based upon a music listener response to specific questions regarding a specific music sample is created. Listener specific music space is created as described above, in S 5004  (FIG. 5B). Listener responses as shown in FIG. 5F, column  500 BB is used to create the music space.  
     [0371] In step S 500 J, music space for a listener is compared to the global space for a specific piece of music. Steps similar to those shown in S 505  (FIG. 5A) may be used create a global space for a specific piece of music. Space comparison is also similar to that described above in FIG. 5A (step S 505 ). If a listener&#39;s response pattern for a music sample is farther than a pre-determined threshold value, then the listener may have to be retrained before listener responses are used in steps S 501 A, S 501 B and S 501 C (FIG. 5A).  
     [0372] In step S 500 K, a music listener space (“People Space”) is created. The music listener space is based upon music listener responses to a set of music samples and a fixed set of questions. For example as shown in FIG. 5H, a music listener provides responses Rs 1  and Rs 1 ′ to a first question for music samples I and II respectively. Rs 1  and Rs 1 ′ are used to locate the listener in the People Space. A matrix (MP) may be formed with average listener responses to plural sets of music samples. Thus for a set of listeners matrix MP includes rows of questions and columns as listeners. The ijth entry of the MP matrix is the jth listener&#39;s average response to the ith question. Thus each listener is located in a space of questions, where the location reflects the general pattern of a listener&#39;s response to the questions  
     [0373] In step S 500 L, listener patterns are evaluated. Plural listeners can be located based upon the pattern of responses to specific questions regarding similar music. Music listeners whose responses are not typical will generally be located farther from other listeners. A pre-determined threshold may be used to determine whether a music listener is typical or not typical.  
     [0374] In step S 500 M, the process calculates ΣZi 2  for a plurality of questions similar to the process step S  500 F in FIG. 5E. Z score values if not equal to a threshold provides a measure of typicality for a music listener. Step S 500 L is conducted on-line while a listener is listening to music. Any feedback associated with deviant Z scores is provided to the listener real time and on-line via the Internet or a private network.  
     [0375] In step S 500 N, the process compares a music listener&#39;s response to historical responses, similar to step S 500 C in FIG. 5E. This step may be performed real time and on-line. If the listener&#39;s response exceeds a threshold then the response may be tagged as “bad” and the listener may be provided feedback.  
     [0376] In step S 5000 , calculate listener response standard deviation similar to step S 500 D in FIG. 5E.  
     [0377] In step S 500 P, compare listener standard deviation with historical standard deviation, similar to step S 500 E in FIG. 5E. Again, this step may be performed real time and on-line.  
     [0378] In step S 500 Q, the process evaluates the total time spent by a listener for a specific question. An example of the time spent is shown as column  500 FF in FIG. 5F. This step may also be conducted real time and on-line while a listener is listening to music samples.  
     [0379] In step S 500 R, the process calculates a Mahalonobis Distance, as described below for a specific user. Mahalonobis distance is calculated for a specific feature vector. For each listener, the average response for specific questions for a similar set of music is recorded and the responses are stored as a “listener profile”. The listener can hence be identified as a point in a multi-dimensional space created similar to the process step S 500 K.  
     [0380] Mahalonobis distance is the standardized distance from the center of listener location points to the actual location of a listener (standardized by the probability density of a multivariate Gaussian distribution) and is used as a measure of typicality. The Mahalonobis distance is the multivariate equivalent of the Z-score and is used similar to Z-scores (Step S 500 M), i.e., listeners with large Mahalonobis distances (exceeding a pre-determined threshold) are tagged as aberrant. The Mahalonobis distance is a multivariate way to standardize distances by a covariance matrix.  
     [0381] The threshold values for the foregoing quality assurance processes are initially determined based on initial data collected from music listeners and experts. However, the threshold values are dynamic and periodically refined as more data is collected.  
     [0382] Measuring Reliability:  
     [0383] The premise for measuring reliability is that music listener&#39;s responses will be consistent if the responses to the same or similar music sample are consistent. Music listeners whose responses have been collected are provided with the same samples in random order. The responses are collected again and compared with the previous responses. If the variation in the responses exceeds a pre-determined threshold, then the music listeners are trained again.  
     [0384] Measuring Discrimination:  
     [0385] Discrimination evaluation identifies listeners who do not use the entire range of available responses for a question. For example, if a listener has to choose from five different options for a specific question and the listener only chooses a few levels compared to historical responses, then the listener&#39;s responses will have low variance compared to the variance of the historical responses. Hence feedback is provided to the listener to make finer distinction between responses and samples.  
     [0386] Quality Assurance Block diagram:  
     [0387]FIG. 5I shows a block diagram that provides a quality assurance system for evaluating music listeners. Listener responses are received as  500 HH same as in FIG. 5F, and sent to the Acquired database  404  (or R&amp;D database  405 ). Some listener responses as shown above are evaluated On-line (Real time via the Internet or a private network) by On Line testing module  500 II and based upon the On-line evaluation, feed back  500 MM is sent to the listener. Off-line evaluation is performed on some aspects of listener responses by an Off Line testing module  500 KK and feedback  500 LL is provided to listeners, based upon the off line evaluation.  
     [0388] System Architecture  
     [0389] User Interface:  
     [0390]FIG. 9 is a block diagram of the overall system architecture that allows content based music searching, according to another aspect of the present invention. FIG. 9 shows a User Interface (UI)  901  that receives a music searcher&#39;s (“user”) request for music. A listener enters the request, based upon the listener&#39;s preferences. An example of UI  901  is shown in FIG. 10A. FIG. 10A shows a genre selector  100 , an emotion selector  101 , a vocal quality selector  102 , a instruments selector  103  and a tempo selector  105 .  
     [0391] Genre selector  100  allows a listener to specify the level and number of descriptors that a listener desires to use. One such option is the use of a genre mixer  100 A as shown in FIG. 10B.  
     [0392] The genre mixer  100 A includes a plurality of variable sliding rulers  108  that allow a listener to set a certain level  109  for a specific genre. For example, as shown in FIG. 10B, a listener may request music with defined levels of Rock, Jazz, Latin, Blues, Folk, etc. It is noteworthy that the present invention is not limited to using a, genre mixer  100 A, and other methods (e.g., a pull down menu etc.) may be used to indicate listener preferences for music genres. Currently a listener may select a specific level for the following genres:  
     [0393] Alternative  
     [0394] Blues  
     [0395] Country  
     [0396] Electronic/Dance  
     [0397] Folk  
     [0398] Gospel  
     [0399] Jazz  
     [0400] Latin  
     [0401] New Age  
     [0402] R&amp;B/soul  
     [0403] Rap/Hip-Hop  
     [0404] Reggae  
     [0405] Rock  
     [0406] The invention is not limited to any particular number of genres, hence future genres may be added to the genre selector  100 A. Based upon listener selection, the current system uses genre as a filter to search for music as described below.  
     [0407] The emotion quality selector  101  enables a listener to specify the emotional quality for music. An emotional quality mixer  101 A is shown in FIG. 10C that allows a listener to adjust emotion levels  111  for different emotions. For example, a listener may select a level of 40 for up beat emotion, 30 for relaxing, 25 for romantic, and zero for the rest. Listener selection for emotional quality determines another filter for the system to search for music, based upon music content.  
     [0408] Currently a listener may select a specific level of the following emotional qualities:  
     [0409] Intense  
     [0410] Upbeat  
     [0411] Aggressive  
     [0412] Relaxing  
     [0413] Mellow  
     [0414] Sad  
     [0415] Romantic  
     [0416] Broken-hearted  
     [0417] The invention is not limited to any particular number of emotional qualities, hence future emotion qualities may be added to the emotional quality selector  101 A. Based upon listener selection, the current system uses emotional quality as a filter to search for music as described below.  
     [0418] A vocal quality selector  102  allows a listener to choose from a vocal ensemble, e.g., a female solo or a male solo. A vocal quality mixer  102 A, as shown in FIG. 10D, also allows a listener to select from other possible ensembles, for example:  
     [0419] Female Solo  
     [0420] Male Solo  
     [0421] Female Duet  
     [0422] Male Duet  
     [0423] Mixed Duet  
     [0424] Female Group  
     [0425] Male Group  
     [0426] Mixed Group  
     [0427] Vocal quality selector  102  (selections not shown) can also allow a listener to choose from various vocal quality levels that may describe qualitative aspects of the vocal components of music, for example:  
     [0428] Smooth  
     [0429] Soulful  
     [0430] Sexy  
     [0431] Great  
     [0432] Powerful.  
     [0433] A vocal quality mixer similar to vocal quality mixer  102 A may also be used to select various levels  113  of vocal quality by a sliding bar  112 , for example a listener may select a level of 50 for “smooth”, 25 for “sexy” and 25 for “great”. It is noteworthy that the invention is not limited to any particular number of vocal qualities, hence future vocal qualities may be added to the vocal quality selector  102  and vocal quality mixer  102 A.  
     [0434] An instrument selector  103  allows a listener to select a plurality of instruments, for example,  
     [0435] Acoustic guitar  
     [0436] Electric guitar  
     [0437] Bass  
     [0438] Drums  
     [0439] Harmonica  
     [0440] Organ  
     [0441] Piano  
     [0442] Synthesizer  
     [0443] Horn  
     [0444] Saxophone  
     [0445] Strings  
     [0446] An instrument mixer and tempo mixer similar to the voice quality mixer  102 A, emotion quality mixer  101 A and genre mixer  100 A may be used to select and/or vary the influence of various instruments and/or music beat. The instrument selector  103  and tempo selector  105  provide other filters for UI engine  902  to search for music based upon music content.  
     [0447] A listener may also input standard search requests for an artist, title, label or album at the search selector  104 . Standard search requests provide Standard Query language (SQL) calls for searching music.  
     [0448] UI  901 , as shown in FIG. 10A also provides a graphical illustration of a music space  106 . A listener may use the pointing device  14  or keyboard  13  (FIG. 1) to use the various options in display  107 , e.g., to view search results, play certain music selections, stop playing music etc.  
     [0449] Appendix “A”, II, also provides a list of filters that are used for content based searching according to the present invention in the music space  106 .  
     [0450] UI Engine:  
     [0451] As shown in FIG. 9, UI  901  is coupled to a U-E engine  902 . A user&#39;s request is submitted to UI engine  902  that searches for a song set based upon a specific listener request.  
     [0452]FIG. 11 shows a block diagram showing various components of UI engine  902 . FIG. 11 shows a XML parser  1001  that receives listener requests from UI  901 . It is noteworthy that the invention is not limited to using a XML parser  1001 , and any other parser that can process UI  901 &#39;s request may be used. XML parser  1001  extracts calls from a listener request and a two step searching step is performed based upon the listener request. In the first step, SQL calls are used to search production database  407  as shown below and with reference to Appendix “A”:  
     [0453] Song Title  
     [0454] Album  
     [0455] Artist  
     [0456] select uid, song_title, artist, album_title from song where song_title=‘SONG TITLE’ 
     [0457] select uid, song_title, artist, album_title from song where song_title=‘ALBUM’ 
     [0458] select uid, song_title, artist, album_title from song where song_title=‘ARTIST’ 
     [0459] 1) Timeline—Filter  13   
     [0460] select uid, song_title, artist, album_title from song where release-year &gt;=filter5.rangelo AND release_year&lt;=filter5.rangehi  
     [0461] 1) Instruments—Filters  21 - 31 , refer to fields v 4 -v 15  of song_vectors ***v 4 =v 6   
     [0462] Select uid, song_title, artist,album_title from song, song vectors where  
     [0463] 1) Vocal Ensemble—Filter  15 , refers to field v 2  of song vectors  
     [0464] Select uid, song_title, artist, album_title from song, song-vectors where [filterX conditions] 
     [0465] The SQL search provides a first set of songs. Using a second search refines this first set of songs. The inferential engine  1003  interacts with the production database  407  and performs a second search for songs in the genre space, emotional quality space and combined space if necessary. The refined search is based upon the similarity modeling as discussed above with respect to Modeling Module  406  (FIG. 5A, Step S 505 ). Results of the refined search are presented as a music set  1002  to the user.  
     [0466]FIG. 9 shows UI engine  902  coupled to the production database  407 , similarity database  407 A and a user log database  903 . User log database  903  is populated by tracking a user&#39;s music listening habits and the websites that a listener may visit while listening to a particular type of music. A listener profile is created that can be used for selective advertising and marketing purposes. Data collected in user log database  903  may also be used to selectively provide music to listeners based upon collected user profile data and music listening habits.  
     [0467]FIG. 9 also shows Research database  405  linked to similarity Modeling Module  406  that is linked to production database  407 , similarity database  407 A and user log database  903 .  
     [0468] Process for content based music searching:  
     [0469]FIG. 12 shows computer executable process steps that allow a listener to search for music based upon music attributes and content. The concept of content based searching as illustrated below is included in a Music Query Language (“MQL”) that allows content based searching.  
     [0470] In step S 1201 , a listener enters a request to search for music in UI  901 . An example of a search request may be to search for music that is mellow, has a strong beat with  50 % blues and  50 % country blend, includes a male vocalist with a powerful voice, and the saxophone as the most important instrument. Hence, the request has the following parameters: “mellow”, “Strong beat”, “ 50 % Blues and  50 % Country”, “Male Vocalist”, “Powerful Voice” and “Saxophone”. It is noteworthy that the foregoing example is merely illustrative and the invention is not limited to the foregoing example.  
     [0471] In step S 1202 , UI engine  902  receives and parses the listener request. XML parser  1001  parses the listener request.  
     [0472] In step S 1203 , UI engines  902  acquire a first song set from production database  407 . The first song set is acquired based upon SQL calls. Music can be searched for “Song Title”, “Album Title”, Name of the Artist, Tempo, or instruments, as shown above and in Appendix “A”.  
     [0473] In step S 1204 , inferential engine  1003  searches for music using selection algorithms that allow searching in the emotional, genre, and/or combined music spaces. Inferential engine search is based upon data stored in production database  407  and similarity modeling principles used by Modeling Module  406  (FIG. 5A, Step S 505 ). Based upon the search request above, one technique for searching that may be used is illustrated below:  
     [0474] (a) Location of 50% Blues and 50% county in the Genre space (Ls);  
     [0475] (b) Determine all the songs that are within a certain distance from location Ls. A predetermined threshold may be used to find the songs within a certain weighted Euclidean distance; for example, choose all songs that are within “X” distance from Ls, where X is a predetermined threshold number.  
     [0476] (c) Provide the list of all songs within X distance from Ls to UI engine  902   
     [0477] In step S 1205 , acquire all music that is similar to the listener request from similarity database  407 A. Generally, similarity database results will be acquired if step S 1204  results are inaccurate.  
     [0478] In step S 1206 , the process presents a music set to the user. UI engine  902  provides the music set to UI  901 . The music set includes the songs obtained by inferential engine  1003  and songs obtained from the similarity database  407 A.  
     [0479]FIG. 13 shows a flow chart of an overall system that allows content based searching for aesthetic commodities.  
     [0480] In step S 1301 , the process collects data that can define a plurality of attributes of a specific or a combination of aesthetic commodities. Data may be acquired as shown above in FIG. 5A. Based upon collected data, a plurality of feature vectors can be defined, as described above.  
     [0481] In step S 1302 , model the data acquired in step S 1301 . The modeling analysis is similar to that shown above and in FIG. 5C 3 . Modeling analysis also creates plural metric spaces similar to the music spaces shown above and in FIG. 5D.  
     [0482] In step S 1303 , the process provides a user interface to a user that may be similar to the user interface shown in FIG. 10A. The user interface will allow a user to define a search criterion based upon attributes of a specific aesthetic commodity.  
     [0483] In step S 1304 , the process performs a search for an aesthetic commodity similar to search performed in steps S 1202 -S 1205  (FIG. 12).  
     [0484] One of the advantages of the present system is that feature vectors can describe music content. This assists in creating a music space for various attributes of music.  
     [0485] Another advantage of the present invention is that since the feature vectors define music attribute, music can be searched based upon music content.  
     [0486] Yet another advantage of the present invention is that any aesthetic commodity may be described by feature vectors and searched based upon content.  
     [0487] Although the present invention has been described with reference to specific embodiments, these embodiments are illustrative only and not limiting. Many other applications and embodiments of the present invention will be apparent in light of this disclosure and the following claims.  
               APPENDIX “A”                          I.       table song_vectors (song_id double NOT NULL PRIMARY       KEY, v1 float, # tempo (continuous) v2 float,        # lead vocal type (integer) (0-8) v3 float, #       focus on background vocals? (bool) (0-1)            #***** boolean instrument filters below *****        v4float,   # prominent acoustic guitar (bool) (0-1)        v5float,   # prominent electric guitar (bool) (0-1)        v6float,   # prominent bass (bool) (0-1)        v7float,   # prominent drums (bool) (0-1)        v8float,   # prominent harmonica (bool) (0-1)        v9float,   # prominent organ (bool) (0-1)        v10float,   # prominent piano (bool) (0-1)        v11float,   # prominent synthesizer (bool) (0-1)        v12float,   # prominent horn (bool) (0-1)        v13float,   # prominent saxophone (bool) (0-1)        v14float,   # prominent strings (bool) (0-1)            #***** continuous genre mixer filters below *****            # these are subject to change v15       float,   # Alternative (continuous) v16 float,        # Blues (continuous)        v17float,   # Country (continuous)        v18float,   # Electronic/Dance (continuous)        v19float,   # Folk (continuous)        v20float,   # Gospel (continuous)        v21float,   # Jazz (continuous)        v22float,   # Latin (continuous)        v23float,   # New Age (continuous)        v24float,   # R&amp;B/Soul (continuous)        v25float,   # Rap/Hip-Hip (continuous)        v26float,   # Reggae (continuous)        v27float,   # Rock (continuous)            #***** continuous Vocal Parameters *****             subject to change v28 float,        # Smooth Voice (continuous)        v29float,   # Soulful Voice (continuous)        v30float,   # Sexy Voice (continuous)        v31float,   # Great Voice (continuous)        v32float,   # Powerful Voice (continuous)            #***** continuous Emotion Parameters        v33float,   # Intense        v34float,   # Upbeat        v35float,   # Aggressive        v36float,   # Relaxing        v37float,   # Mellow        v38float,   # Sad        v39float,   # Romantic        v40 float,   If Broken-hearted        #**** continuous coordinate parameters        v41 float,   # coordinate 1        v42 float,   # coordinate 2        v43 float,   # coordinate 3        v44 float,   # coordinate 4        v45 float,   # coordinate 5        v46 float,   # coordinate 6        v47 float,   # coordinate 7        v48 float,   # coordinate 8        v49 float,   # coordinate 9        v50 float   # coordinate 10            #***** cluster related stuff        v51 int,   # uid of parent song        v52 int,   # level of song (if it&#39;s a std candle       song)             # will be −1 if it&#39;s a normal leaf song        v53 float,   # continuous quantitative filter       measurement        v54 int,   # number of songs in the cluster             represented by If this song        v55 int   # release year       )       II. Filter Definitions        Filter Structure:       &lt;filter&gt;        &lt;uid&gt;5&lt;/uid&gt;        &lt;value&gt;.3&lt;value&gt;*        &lt;direction&gt;3.14159&lt;/direction&gt;*        &lt;rangelo&gt;0&lt;/rangelo&gt;*        &lt;rangehi&gt;6.28318&lt;/rangehi&gt;*        &lt;booleanlist&gt;0 2 4 7 9&lt;/booleanlist&gt;*        &lt;booleantype&gt;0&lt;/boolean type&gt;*        &lt;booleanstring&gt;(1&amp;&amp;5)||(3&amp;&amp;S)&amp;&amp;! (6||3)&lt;/booleanstring&gt;*        **       &lt;/filter&gt;       * these fields are optional depending on the filter       ** this generalized boolean query mechanism is subject to       change       List of Filters/controls with their corresponding fields:                                         FilterName   uid   value   direction   rangelo   rangehi   boolean index list                         Genre Mixer Parameters: (uid&#39;s 0-99)                                         Alternative   0   0-1 (continuous)   —   —   —   —       Blues    1   0-1 (continuous)   —   —   —   —       Country    2   0-1 (continuous)   —   —   —   —       Electronic/Dance    3   0-1 (continuous)   —   —   —   —       Folk    4   0-1 (continuous)   —   —   —   —       Gospel    5   0-1 (continuous)   —   —   —   —       Jazz    6   0-1 (continuous)   —   —   —   —       Latin    7   0-1 (continuous)   —   —   —   —       New Age    8   0-1 (continuous)   —   —   —   —       R&amp;B/Soul    9   0-1 (continuous)   —   —   —   —       Rap/Hip-Hop    10   0-1 (continuous)   —   —   —   —       Reggae    11   0-1 (continuous)   —   —   —   —       Rock    12   0-1 (continuous)   —   —   —   —                         Vocal Quality (uid&#39;s 200-299)                                         Lead Vocals   200   —   —   —   —   0-8 (int)                         ** note: For Lead Vocals) the meaning of the values are the following:       0 = female solo, 1 = male solo, 2 = female duet, 3 = male duet, 4 = mixed duet, 5 =       female group, 6 = male group, 7 = mixed group, 8 = instrumental.       The &lt;boolean type&gt;parameter should be frozen at 1 for ‘or.’       Thus a typical XML filter structure for this parameter may be:        &lt;filter&gt;         &lt;uid&gt;15&lt;/uid&gt;          &lt;booleanlist&gt;0 2 4&lt;/booleanlist&gt;          &lt;booleantype&gt;1&lt;/booleantype&gt;         &lt;/filter&gt;       which means, provide songs that are either ‘female solo vocals,’ ‘female duet vocals,’ or ‘mixed       duet vocals.’       *** note: an additional field is included in the XML filter structure, &lt;booleanstring&gt; to provide       more powerful, arbitrary combinations of boolean values and operators.                 Vocal Mixer Parameters (uid&#39;s 300-399)                                         Smooth Voice   300   0-1 (continuous)   —   —   —   —       Soulful Voice   301   0-1 (continuous)   —   —   —   —       Sexy Voice   302   0-1 (continuous)   —   —   —   —       Great Voice   303   0-1 (continuous)   —   —   —   —       Powerful Voice   304   0-1 (continuous)   —   —   —   —       Vocal Circumplex   305   0-1 (continuous)   0-2PI   —   —   0-10 int                   (contin-                   uous)                         *the circumplex arranges the previous 5 parameters on a circle.                 Instrument Parameters (uid&#39;s 400-499)                                         Acoustic Guitar   400   0-1 (boolean)   —   —   —   —       Electric Guitar   401   0-1 (boolean)   —   —   —   —       Bass   402   0-1 (boolean)   —   —   —   —       Drums   403   0-1 (boolean)   —   —   —   —       Harmonica   404   0-1 (boolean)   —   —   —   —       Organ   405   0-1 (boolean)   —   —   —   —       Piano   406   0-1 (boolean)   —   —   —   —       Synthesizer   407   0-1 (boolean)   —   —   —   —       Horn   408   0-1 (boolean)   —   —   —   —       Saxophone   409   0-1 (boolean)   —   —   —   —       Strings   410   0-1 (boolean)   —   —   —   —                         Emotion Mixer Parameters (uid&#39;s 500-599)                                         Intense   500   0-1 (continuous)   —   —   —   —       Upbeat   501   0-1 (continuous)   —   —   —   —       Aggressive   502   0-1 (continuous)   —   —   —   —       Relaxing   503   0-1 (continuous)   —   —   —   —       Mellow   504   0-1 (continuous)   —   —   —   —       Sad   505   0-1 (continuous)   —   —   —   —       Romantic   506   0-1 (continuous)   —   —   —   —       Broken-hearted   507   0-1 (continuous)   —   —   —   —                         III. Relevant Tables in the Production Database       table songs (        uid double NOT NULL PRIMARY KEY,        created datetime,        song_title varchar(255),        artist varchar(255),        genre double,        album_title varchar(255),        release_year int, # this is used for the timeline filter        parent double # parent song, null if we&#39;re the highest in this       genre       )        create table filters (        uid int NOT NULL PRIMARY KEY,        name varchar(255)        column_name varchar(18) NOT NULL, # maps to columns in       song_vectors        type int # TBD, probably used for whether this is an SQL or other       param            # for now, 0 = SQL only, 1 = attrvector param for       Matlab       )\g