Patent Application
20090326914
Determining a geographic match, or geocoding, to a text search is a relatively well studied problem. There are numerous web-based and commercial mapping products used for route planning, fuel/cost estimation, and simple travel planning. Such products include Google Maps™, Yahoo Maps™, and Windows Live Local™. Each of these products uses the same language (such as English) in both the underlying database and the user interface. Attempts to geocode location queries in a language different from the underlying database, particularly when the language uses a different script or alphabet, have a very low success rate, if any. For example, queries in Hindi, Arabic, or Japanese made against an English language geo-database may have a very low success rate.
Geocoding also includes more than one type of query. One is a structured address, for example, 233 South Wacker Drive, Chicago, Ill., 60606, is well formed in a conventional U.S. address format, with no misspellings. These queries, in English, usually return accurate results. An unstructured query, such as Sears Tower, or the Loop, may also return accurate results for some well known landmarks or features.
However, several factors can greatly reduce the accuracy of results for geocoding queries. One factor is ill-formed queries, with either data missing or data in a non-standard sequence. Another factor is misspellings in the query. A third factor is queries in a language different from the underlying database, which may be even further complicated by queries in languages with alphabets or character sets different from the underlying geographic database.
Yet other factors that raise inaccuracy in results for geocoding queries include different address formats across national boundaries, extraneous terms (that don't match anything) or non-unique identifiers (for example, there are over 1000 “1st Cross” roads in Bangalore, India).
Geographic data, and particularly map data, are intrinsically tied to given regions, and hence are available predominantly in local languages. In addition, the business, resource and interoperability considerations often dictate that such data are created only for a small set of languages. Yet in today's increasingly globalized world, there is a clear need for accessing geographic information across languages. Examples range from Indian citizens who want to query in their own local languages, the land records traditionally created in English, through cross-lingual geographic indexing of documents, to visitors at the 2008 Olympics who will want to find Beijing locations using many languages other than Mandarin Chinese. Despite the clear motivation for crosslingual location searches, to the best of our knowledge, there are no academic or commercial systems that support general crosslingual location search.
A possible approach to crosslingual location search would be to create and represent all geographic entities in all languages, but this is financially and logistically unviable (for example, a country of the size of the US has several million unique streets, localities, landmarks, etc., and moreover, these are updated on a continual basis). Alternatively, one could use a machine translation/transliteration system to convert the query terms to the target language, and then process the results in a monolingual geocoder in the target language. However, the linguistic ambiguities inherent in the process, increase the search space exponentially, and degrade the accuracy of results greatly. In addition, the fact that descriptions of locations and addresses are structured differently in different regions—or may be unstructured altogether—makes cross lingual location search a particularly difficult challenge.
A geocoding search uses a combination of translation, transliteration, and fast spatial lookup to prune a list of candidate locations when performing a location search. The technique works for both ill-formed or misspelled queries as well as queries in languages different from the language of the underlying geographic database. Addition of new languages or alphabets requires only straightforward training.
A demonstration system using this technique provides accurate results for both structured and unstructured queries in English, Hindi, Arabic, and Japanese.
The technique parses a query into tokens (groups of text) and performs a transliteration of proper names, as well as a translation and transliteration of common nouns. This process may result in a substantial number of combinations of translations and transliterations for each token. Each token is then keyed to a spatial database. The spatial matches are compared for overlaps, or constraints and tokens having a spatial relationship are selected for analysis using actual geometric data.
The spatial database is not simply a list of locations, but includes a union of geometric boundaries for every a geometry (bounded location) having a common location. For example, a spatial database entry for “London” may include geometries for London, England; London Connecticut; and London Bridge in Arizona.
Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the legal scope of the description is defined by the words of the claims set forth at the end of this disclosure. The detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims.
It should also be understood that, unless a term is expressly defined in this patent using the sentence “As used herein, the term ‘______’ is hereby defined to mean . . . ” or a similar sentence, there is no intent to limit the meaning of that term, either expressly or by implication, beyond its plain or ordinary meaning, and such term should not be interpreted to be limited in scope based on any statement made in any section of this patent (other than the language of the claims). To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term by limited, by implication or otherwise, to that single meaning. Finally, unless a claim element is defined by reciting the word “means” and a function without the recital of any structure, it is not intended that the scope of any claim element be interpreted based on the application of 35 U.S.C. §112, sixth paragraph.
Much of the inventive functionality and many of the inventive principles are best implemented with or in software programs or instructions and integrated circuits (ICs) such as application specific ICs. It is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation. Therefore, in the interest of brevity and minimization of any risk of obscuring the principles and concepts in accordance to the present invention, further discussion of such software and ICs, if any, will be limited to the essentials with respect to the principles and concepts of the preferred embodiments.
With reference to
A series of system busses may couple various system components including a high speed system bus 123 between the processor 120, the memory/graphics interface 121 and the I/O interface 122, a front-side bus 124 between the memory/graphics interface 121 and the system memory 130, and an advanced graphics processing (AGP) bus 125 between the memory/graphics interface 121 and the graphics processor 190. The system bus 123 may be any of several types of bus structures including, by way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus and Enhanced ISA (EISA) bus. As system architectures evolve, other bus architectures and chip sets may be used but often generally follow this pattern. For example, companies such as Intel and AMD support the Intel Hub Architecture (IHA) and the Hypertransport™ architecture, respectively.
The computer 110 typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computer 110 and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can accessed by computer 110.
The system memory 130 includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) 131 and random access memory (RAM) 132. The system ROM 131 may contain permanent system data 143, such as identifying and manufacturing information. In some embodiments, a basic input/output system (BIOS) may also be stored in system ROM 131. RAM 132 typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processor 120. By way of example, and not limitation,
The I/O interface 122 may couple the system bus 123 with a number of other busses 126, 127 and 128 that couple a variety of internal and external devices to the computer 110. A serial peripheral interface (SPI) bus 126 may connect to a basic input/output system (BIOS) memory 133 containing the basic routines that help to transfer information between elements within computer 110, such as during start-up.
A super input/output chip 160 may be used to connect to a number of ‘legacy’ peripherals, such as floppy disk 152, keyboard/mouse 162, and printer 196, as examples. The super I/O chip 160 may be connected to the I/O interface 122 with a bus 127, such as a low pin count (LPC) bus, in some embodiments. Various embodiments of the super I/O chip 160 are widely available in the commercial marketplace.
In one embodiment, bus 128 may be a Peripheral Component Interconnect (PCI) bus, or a variation thereof, may be used to connect higher speed peripherals to the I/O interface 122. A PCI bus may also be known as a Mezzanine bus. Variations of the PCI bus include the Peripheral Component Interconnect-Express (PCI-E) and the Peripheral Component Interconnect-Extended (PCI-X) busses, the former having a serial interface and the latter being a backward compatible parallel interface. In other embodiments, bus 128 may be an advanced technology attachment (ATA) bus, in the form of a serial ATA bus (SATA) or parallel ATA (PATA).
The computer 110 may also include other removable/non-removable, volatile/nonvolatile computer storage media. By way of example only,
Removable media, such as a universal serial bus (USB) memory 153, firewire (IEEE 1394), or CD/DVD drive 156 may be connected to the PCI bus 128 directly or through an interface 150. A storage media 154 similar to that described below with respect to
The drives and their associated computer storage media discussed above and illustrated in
The computer 110 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 180 via a network interface controller (NIC) 170. The remote computer 180 may be a personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computer 110. The logical connection between the NIC 170 and the remote computer 180 depicted in
In some embodiments, the network interface may use a modem (not depicted) when a broadband connection is not available or is not used. It will be appreciated that the network connection shown is exemplary and other means of establishing a communications link between the computers may be used.
The bulk (not all) of words in geographic entity names are proper nouns, and in general cannot be translated readily like other parts of speech (such as, common nouns, adjectives, verbs, etc.) that are a part of standard bilingual dictionaries. Where source and target language share the same script, the problem is not readily apparent as the proper nouns are generally identical (for example, “Berlin” is correct in German, English, and Italian, though some variations in orthography and pronunciation exist, such as, “Antwerp” is “Antwerpen” in Dutch, “London” is “Londres” in Spanish, etc.). For different scripts, a name in the source language needs to be transliterated, that is, converted into a string in the target script which preserves the original pronunciation of the source word, yet conforming to the pronunciation rules of the target language.
Since the mapping between pronunciation and spelling is not fully deterministic in both languages, transliteration is an inherently ambiguous process. For example, the transliterations of “” (representing “Palmer”) could be “Palmer”, “Bilmar” etc. [1], as Arabic does not distinguish between “b” and “p” and short vowels may not be represented in Arabic orthography. Similarly, the English transliterations of Hindi syllable “
” could be highly ambiguous, as many English phonetic constructs, such as, “key”, “kee”, “ki” and “kea” are possible. As a consequence, for each source word, several transliteration candidates have to be considered to achieve a reasonable confidence that the correct transliteration is included. This leads to a large number of possible interpretations of a multiword query, as illustrated in Table 1, which shows some machine transliteration results for the Arabic address fragment “
”, which should be transliterated as “Palmer Road Redbridge London”.
Another source of ambiguity is that queries can contain common nouns, which can both be translated and transliterated. For example, depending on context, either the transliteration “al-matar” or the translation “airport” may be preferable for the word “” in an Arabic language query. Consider the impact of having to consider many alternatives to each word in the query, especially in the absence of tokens such as commas to delimit one potential term from another. If k transliterations/translations need to be considered for each word in an n word query, which can be partitioned into subsequences in 2n-1 ways, then the total number of possible combinations of non-overlapping subsequences to be considered is kn2n-1, which, even for the short (four word) Arabic query above, with k=5, amounts to 5000 combinations.
The crosslingual challenges discussed above compound with existing monolingual challenges. The ambiguity in spellings, names and orderings inherent in crosslingual matching make simple composition of translation/transliteration with monolingual location search an unviable option.
To address these issues, in response to a query at block 202, a language detector may be activated at block 204. The language detector may parse the query into individual tokens, as required, and then determine a source language for each token. In some cases, the query may be in mixed languages, in which case, the language detector may identify individual tokens for processing in separate languages. An individual token or tokens ‘q’ may be directed to blocks 206 and 212.
At block 206, a language-specific machine transliteration tool may be used to process the query tokens. The output of block 206 may be a list of machine transliterated query tokens T(q). The machine transliterated tokens may be provided to block 214. In one embodiment, the addition of new languages requires only a change to this block and the language detector at block 204, the other blocks being language independent. One embodiment of the machine transliteration system uses a Viterbi training alignment and a Maximum Entropy classifier to generate target language transliteration candidates for a source language word. An alignment algorithm may be used to align each single character of a source word with zero or more characters in the target language transliteration. Because the classifier takes the strictly monotonic nature of alignments in transliteration into consideration, it is better suited for the task than general machine translation alignment tools. Based on the resulting alignments, a maximum entropy classifier may be trained to estimate the probability that source language character, in the context of the 3 preceding and the 3 following source characters, should be transliterated to a given target language string.
Returning to block 212, the token or tokens ‘q’ may be translated via a lookup table of common nouns, such as “airport.” The output of block 212 may be one or more tokens L(q).
At block 214, a cross product of the most promising text subsequences may be generated. This set of transformed subsequences may be ranked by probabilistic estimates provided by block 206. The output of block 214, TL(q), a union of the transliterated results of block 206 and the translation results of block 212 may be passed to blocks 208 and 216.
At block 216, the TL(q) terms may be matched in a fuzzy search of geographic entities. A previously prepared database FI(S) of geometric footprints and their associated attributes (e.g. names) may be used for comparison with the token or tokens TL(q). Because this first-phase screen is used to rank tokens by confidence of correct identification, the geometric footprint may include all spatial regions with a common attribute. For example, geometries for all spatial regions named London (London, UK; London, Connecticut; London, Ohio; etc.) may be grouped, whether or not a geographic overlap or constraint exists. That is, the database may have records with a common name, e.g. “London”, and one or more spatial representations of all cataloged locations having that common name.
At block 208, each machine translated token T(q) may be abstracted into a phonetic representation of the query token, that is, with no further language-specific connotations. The phonetic abstraction may be performed after the fashion of the known SOUNDEX algorithm, that attempts to capture the phonetic essence of the token. In one embodiment, a rule-based abstraction engine may be used, but other phonetic abstraction algorithms may also be used. The output of block 208, the abstracted version of TL(q), A(TL(q)), may be provided to block 210.
At block 210, A(TL(q) may be compared with a second database FI(A(S)). The second database, FI(A(S)), is essentially the same as database FI(S), with the exception that the attribute (e.g. name) data is also abstracted using the phonetic abstraction process used at block 208. That is, the database FI(A(S)) may have a records with a common name, e.g. “London”, one or more phonetic names, and one or more spatial representations of all cataloged locations having that common name. This allows matching the abstracted query term to be fuzzy matched with an abstracted name of a geographic spatial region. The output of block 210, referred to as an Approximate Match Record, may be combined with the Approximate Match Record output of block 216 and sent to block 218.
At block 218, the resulting list of AMRs contributed by both blocks 210 and 216 may be ordered using one or more measures of textual affinity, including machine translation probabilities and edit distance scores returned by the fuzzy lookups performed in blocks 210 and 216. In one embodiment, the measures applied to the abstracted lookup AMRs from block 216 may be weighted slightly lower than the other AMRs. The output of block 218 may be a list of candidate matches that have some measure of spatial affinity with the original query token or tokens. For example, the common name or names associated with the overlapping spatial region or regions may be selected and these candidate matches may then be passed to a more definitive geographic matching tool. The latter tool may provide a more concise list of possible matches back to a requesting entity, such as a user or geographic information system (GIS).
The actual process of computing and representing the geographic footprints of query tokens is discussed in more detail in co-pending application “FAST APPROXIMATE SPATIAL REPRESENTATIONS FOR INFORMAL RETRIEVAL,” filed on the same day as this application with attorney docket number 30835/323326.
The use of the Approximate Match Records to complete a geo-reference search is discussed in co-pending U.S. patent application Ser. No. 11/831,939, filed Jul. 31, 2007, with the title, “Generalized Location Identification,” which is hereby incorporated by reference.
Referring to
However, of these, only the sets of entities that spatially overlap, London 312, Redbridge 318 and Palmer Road 316 are plausible candidates. Thus, the fact that three particular entities named “Palmer Road”, “Redbridge”, and “London” (in the U.K.) all spatially overlap, gives a powerful reason to pick this interpretation from all possible interpretations of the query. Moreover, the region of overlap 320 (the gray region in the figure) of these three entities defines the geometric scope of the result.
The use of a combination of translation, transliteration, and fuzzy phonetic lookup provides tokens useful for presentation to a geographic spatial matching tool. The binary tree classification for geographic regions and extremely fast matching process afforded by such a classification system (as described in the co-pending application referenced above) allows practical, timely, cross-lingual searches for map locations and points of interest. As discussed above, the sheer number of possible combinations of translation or transliteration make current techniques impractical or impossible for widespread use. As disclosed above, the ability to perform searches in one language on a geographic database in another language opens a number of mapping applications to a worldwide audience for which such tools were not practically available. Similarly, providers of geographic data can open new markets for GIS applications, paid search, and sponsored searches without tedious and expensive translation of massive geographic databases.
Although the foregoing text sets forth a detailed description of numerous different embodiments of the invention, it should be understood that the scope of the invention is defined by the words of the claims set forth at the end of this patent. The detailed description is to be construed as exemplary only and does not describe every possibly embodiment of the invention because describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims defining the invention.
Thus, many modifications and variations may be made in the techniques and structures described and illustrated herein without departing from the spirit and scope of the present invention. Accordingly, it should be understood that the methods and apparatus described herein are illustrative only and are not limiting upon the scope of the invention.
This patent is related to the U.S. patent application entitled, “FAST APPROXIMATE SPATIAL REPRESENTATIONS FOR INFORMAL RETRIEVAL,” filed on the same day as this application with attorney docket number 30835/323326.
