Patent Publication Number: US-11048886-B2

Title: Language translation by dividing character strings by fixed phases with maximum similarity

Description:
TECHNICAL FIELD 
     The present disclosure relates to a translation device and a translation method for automatic translation of data input in a first language into a second language and output of a translation result. 
     BACKGROUND ART 
     There has been known a translation method by means of a machine translation system, including dividing an input sentence into short portions and translating each of the divided portions, in view of the fact that a long input sentence tends to cause mistranslation. Sentence division processing includes repeatedly dividing a single sentence and calculating the most appropriate degree of a divided position for each divisional sentence in accordance with a language model. This processing is repeated until the sentence becomes undividable, to obtain candidate divisional sentences (for example, see PTL 1). A divisional sentence having a high similarity is selected from the candidate divisional sentences with reference to a corpus, and is translated. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Unexamined Japanese Patent Publication No. 2006-18354 
     SUMMARY 
     Such a conventional method involves calculation of appropriateness degree every time an input sentence is divided, and subsequent translation. This method accordingly includes a large amount of calculation from division processing to output of a translation result, and takes time. 
     It is an object of the present disclosure to improve translation speed of automatic translation with reference to a fixed phrase. 
     A translation device according to an aspect of the present disclosure includes a character string output unit, a fixed phrase acquisition unit, a matching unit, a division processor, and a translation result output unit. The character string output unit outputs a plurality of character strings each configuring at least part of text in a first language and including a head character of the text, in order of character string length. The fixed phrase acquisition unit acquires a fixed phrase in the first language associated with a translation phrase in a second language. The matching unit calculates a similarity between each of the character strings and the fixed phrase in order of character string length. The division processor divides the text at a position achieving a maximum similarity among values of the similarity exceeding a first threshold. The translation result output unit outputs the translation phrase as translation of the text thus divided. 
     A translation method according to another aspect of the present disclosure includes: outputting a plurality of character strings each configuring at least part of text in a first language and including a head character of the text, in order of character string length; acquiring a fixed phrase in the first language associated with a translation phrase in a second language; calculating a similarity between each of the character strings and the fixed phrase in order of the character string length; dividing the text at a position achieving a maximum similarity among values of the similarity exceeding a first threshold; and outputting the translation phrase as translation of the text thus divided. 
     The present disclosure achieves improvement in translation speed of automatic translation with reference to a fixed phrase. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a configuration diagram of an entire system according to a first exemplary embodiment. 
         FIG. 2  is a configuration diagram of a translation device according to the first exemplary embodiment. 
         FIG. 3  is a functional configuration diagram of a translation unit included in the translation device. 
         FIG. 4  is a flowchart of behavior of the translation device. 
         FIG. 5A  is a flowchart of translation processing executed by the translation device. 
         FIG. 5B  is a flowchart of subsequent translation processing executed by the translation device. 
         FIG. 6  is an explanatory view of matching processing included in the translation processing. 
         FIG. 7A  is a graph indicating a result of similarity calculation included in the translation processing. 
         FIG. 7B  is a graph indicating another result of the similarity calculation included in the translation processing. 
         FIG. 8A  is a chart indicating exemplary data of progress of the similarity calculation included in the translation processing. 
         FIG. 8B  is a chart indicating different exemplary data of progress of the similarity calculation included in the translation processing. 
         FIG. 9  is a graph indicating a result of different similarity calculation included in the translation processing. 
         FIG. 10  is an explanatory view of translation processing according to a different exemplary embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Exemplary embodiments will now be described in detail below with reference to the drawings where appropriate. The following description may not include unnecessarily detailed description. For example, the following description may not include detailed description of a well-known matter and repeated description of substantially identical configurations. This is to prevent unnecessary redundancy in the following description and to facilitate comprehension by those skilled in the art. 
     The inventor provides the accompanying drawings and the following description to help those skilled in the art to fully comprehend the present disclosure, but does not intend to limit subject matters recited in the claims with the drawings and the description. 
     First Exemplary Embodiment 
     1-1. Configuration 
       FIG. 1  depicts a configuration of entire system  1  including server device  10  embodying translation device  110  (see  FIG. 2 ) according to an exemplary embodiment of the present disclosure. System  1  described in the present exemplary embodiment is installed in an aircraft. System  1  includes server device  10 , a plurality of display devices  20  connectable wirelessly or wiredly to server device  10 , microphone  30 , and speaker  40 . Display devices  20  are terminal computers disposed at respective seats for passengers of the aircraft. 
     1-1-1. Configuration of Server Device 
     Server device  10  is a computer device including central processing unit (CPU)  11 , read only memory (ROM)  12 , random access memory (RAM)  13 , input interface  14 , output interface  15 , communication interface  16 , and storage unit  17  (exemplifying a fixed phrase storage). 
     CPU  11  is a processor or a circuit configured to execute processing according to a predetermined program. ROM  12  stores a control program describing a processing procedure of CPU  11 , and the like. RAM  13  functions as a work memory and temporarily stores a control program and data. Input interface  14  is a connection unit to be connected to microphone  30  and receives A/D converted voice data from microphone  30 . Output interface  15  is a connection unit to be connected to speaker  40  and transmits D/A converted voice to speaker  40 . Communication interface  16  is a communication circuit configured to communicate wirelessly or wiredly with display devices  20 . 
     Storage unit  17  is a magnetic memory device like a hard disk drive (HDD), or a memory device like a semiconductor memory, and is configured to store programs for an application, an operating system (OS), and the like, as well as various data. Storage unit  17  includes database DB (see  FIG. 2 ) configured to hold various data referred to by CPU  11 , as to be described later. Storage unit  17  may be connected to server device  10 , as a memory device separate from server device  10 . 
     Microphone  30  is connected to server device  10  and is configured to receive voice of utterance by a cabin crew or the like and output voice data. A cabin is provided with a plurality of speakers  40  configured to output voice received from output interface  15 . 
     1-1-2. Configuration of Translation Device 
       FIG. 2  depicts a configuration of translation device  110  according to the present exemplary embodiment. Translation device  110  is configured to translate data in Japanese (exemplifying a first language) input by means of voice into text in a language like English (exemplifying a second language). 
     Translation device  110  includes voice acquisition unit  111 , voice recognizer  112 , text generator  113 , translation unit  114 , and translation result output unit  115 . Voice acquisition unit  111 , voice recognizer  112 , text generator  113 , translation unit  114 , and translation result output unit  115  are each embodied by CPU  11  referring to data in storage unit  17  and executing a predetermined program. 
     Voice acquisition unit  111  acquires voice data from microphone  30 . Voice recognizer  112  recognizes the voice data thus acquired in accordance with a predetermined model stored preliminarily. Text generator  113  converts the voice data thus recognized to text. The text includes character information or a character string that can be converted to voice or can be displayed on a screen. 
     Translation unit  114  translates the text thus generated. 
       FIG. 3  depicts principal functional units included in translation unit  114 . Translation unit  114  includes character string output unit  1141 , fixed phrase acquisition unit  1142 , matching unit  1143 , similarity determiner  1144 , division processor  1145 , and translation processor  1146 . 
     Character string output unit  1141  acquires text from text generator  113  and executes character string output processing of outputting character strings that are extracted from the text in the first language while sequentially increasing one character from a head character. Fixed phrase acquisition unit  1142  acquires a plurality of fixed phrases in Japanese stored in storage unit  17 . Each of the fixed phrases is associated with a translation phrase in the second language. Matching unit  1143  executes matching processing of comparing each of the acquired character strings including characters sequentially increased one by one with each of the fixed phrases, and calculating a similarity between each of the acquired character strings and each of the fixed phrases. Similarity determiner  1144  executes similarity determination processing of selecting a fixed phrase having a maximum similarity from fixed phrases having calculated similarity values exceeding a first threshold. Division processor  1145  executes division processing of dividing the acquired character string at a position achieving the maximum similarity between the character string and the selected fixed phrase. Translation processor  1146  executes translation processing of acquiring a translation phrase in the second language for the selected fixed phrase. 
     Translation unit  114  applies as necessary, character string output processing, matching processing, similarity determination processing, division processing, and translation processing to text after the position divided by division processor  1145 . 
     Translation result output unit  115  outputs a result of translation processing executed by translation unit  114 . Specifically, translation result output unit  115  outputs the translation phrase as a translation of the text thus divided. The translation result is converted to voice to be outputted via speaker  40 . The translation result converted to voice is alternatively transmitted to each display device  20  so as to be output from display device  20  via an earphone or the like. The output translation result may alternatively be presented as character information on display  29  (see  FIG. 1 ) of each display device  20 . 
     Storage unit  17  holds various data stored as database DB. 
     1-1-3. Contents of Database 
     Database DB stores scene information and fixed phrase information associated with each other. 
     Scene Information 
     The scene information indicates time and an environment of the aircraft, and includes a current scene. The scene information is exemplarily set chronologically in actual aircraft operation such as boarding, taxiing on a runway (before taking off), taking off, flying stably, landing, taxiing on a runway (after landing), or deplaning. The scene information further includes information indicating a scene of utterance at predetermined timing, such as in-flight service guidance or in-flight sales guidance. The scene information still further includes information indicating an unpredictable scene such as emergency contact upon occurrence of significant turbulence of the aircraft, or the like. 
     Fixed Phrase Information 
     As indicated in  FIG. 6 , the fixed phrase information includes fixed phrases in Japanese and translation phrases for the fixed phrases associated with scene information. 
     1-1-4. Configuration of Display Device 
     Each display device  20  is a computer device disposed at each seat of the aircraft and including a display configured to present a screen. As depicted in  FIG. 1 , each display device  20  includes CPU  21 , ROM  22 , RAM  23 , output interface  25 , communication interface  26 , memory  27 , input unit  28 , and display  29 . 
     CPU  21  is a processor or a circuit configured to process a command or data and output a result of the processing. ROM  22  stores a control program describing a processing procedure of CPU  21 , and the like. RAM  23  functions as a work memory and temporarily stores a control program and data. 
     Output interface  25  is a connection unit connected to a voice output unit such as an earphone (not depicted), and outputs voice data received from server device  10  or the like. 
     Communication interface  26  is a communication circuit configured to be communicable wiredly or wirelessly with server device  10  or different equipment provided in the aircraft. Memory  27  is a storage circuit such as a semiconductor memory and stores data like an image. 
     Input unit  28  accepts input operation by a user at the corresponding seat via a touch panel, a keyboard, or a pointing device (e.g. mouse). Display  29  is configured by a liquid crystal panel, an organic electroluminescence (EL) panel, or a panel similar to any one of these panels, and includes a screen presenting a processed image. Display  29  alternatively presents text of a translation result generated by translation device  110 . 
     1-2. Behavior 
     Server device  10  (translation device  110 ) according to the present disclosure will be described below in terms of behavior. 
     1-2-1. Entire Behavior of Translation Device 
       FIG. 4  depicts an entire control flow executed by translation device  110 . Described below is processing of translating contents of announced utterance in the first language by a cabin crew in the aircraft into the second language. 
     S 100 : Voice acquisition unit  111  in translation device  110  acquires voice data from microphone  30 . 
     S 200 : Voice recognizer  112  applies voice recognition processing to the voice data thus acquired. 
     S 300 : Text generator  113  converts voice recognized data to text. 
     S 400 : Translation unit  114  applies translation processing to the text obtained by conversion, as to be described later. 
     S 500 : Translation result output unit  115  outputs data of a translation result obtained by the translation processing. 
     S 600 : The data of the translation result is converted to voice data, to be output by means of voice via speaker  40  or to be transmitted to display device  20  at each seat and output by means of voice via the earphone. The data of the translation result may alternatively be presented by means of text on display  29  of each display device  20 . 
     1-2-2. Translation Processing 
       FIG. 5A  and  FIG. 5B  depict a flow of translation processing executed by translation unit  114  (see  FIG. 2  and  FIG. 3 ) in step S 400  in  FIG. 4 . 
     S 401 : Translation unit  114  acquires an input character string converted to text. Described in this case as an exemplary sentence is text T 10  including text T 11  meaning “Thank you for boarding today.” and text T 12  meaning “This flight is Panasonic Airlines flight number  100 .”, as depicted in  FIG. 6 . 
       FIG. 6  particularly depicts an overview of matching processing between character strings and fixed phrases in translation processing executed by translation unit  114  (see  FIG. 3 ) according to the present exemplary embodiment. The present exemplary embodiment includes extracting character strings as calculation targets (hereinafter, called target character strings) from a character string being input (obtained by converting contents of utterance to text, hereinafter called an input character string), and calculating the similarity. As depicted in  FIG. 6 , the target character strings being output include characters sequentially increased one by one, and each of the output target character strings is compared with all the fixed phrases. 
     S 402 : Translation unit  114  sets an initial value of a candidate fixed phrase flag to “zero”. The candidate fixed phrase flag is provided for each of the fixed phrases and is set to “one” for a fixed phrase having values of similarity exceeding a predetermined threshold (first threshold), as to be described later. 
     S 403 : Translation unit  114  sets a head position of each target character string to “one”. In this case, translation unit  114  sets the head position of each target character string as a similarity calculation target included in the input character string. 
     S 404 : Translation unit  114  sets a terminal position to “a value of the head position+n”. In this case, translation unit  114  sets the terminal position of each target character string included in the input character string. 
     The value “n” is a constant for setting of the terminal position of a target character string. The value n is an integer more than or equal to zero, and corresponds to a minimum number of characters necessary for matching processing with a fixed phrase. First one or two characters are often insufficient for measurement of the similarity to a fixed phrase. Preliminarily setting the number of characters of a calculation target character string to a plurality of numbers at the start of calculation will achieve suppression of an initial amount of calculation in comparison to a case of starting the number of characters from one. As depicted in  FIG. 6 , assume an exemplary case where the input character string starts with text T 11  and the value “n” is set to “two”. In this case, the initial terminal position is set to a terminal position of target character string A 3  obtained as the value of the head position+2. 
     S 405 : Translation unit  114  calculates the similarity between each target character string obtained by extracting a character string between the head position and the terminal position thus set and each of the fixed phrases (matching processing). 
     As depicted in  FIG. 6 , assume an exemplary case where the input character string is text T 10  and the character string set in step S 404  is target character string A 3 . In this case, target character strings A 3 , A 4 , A 5 , . . . are sequentially determined as to whether or not to be similar to each of the fixed phrases. The similarity can be calculated in accordance with a publicly known technique (e.g. the vector space model). 
     S 406 : Translation unit  114  determines whether or not the similarity between the target character string and each of the fixed phrases exceeds the first threshold. The process flow proceeds to step S 407  if the similarity exceeds the first threshold, whereas the process flow proceeds to step S 408  if the similarity is less than or equal to the first threshold. 
     The first threshold serves as a criterion of whether or not the fixed phrase highly possibly matches a target character string. 
     In an exemplary case where the input character string starts with text T 11 , matching processing with fixed phrase B 1  (see  FIG. 6 ) has a result indicated in  FIG. 7A . This exemplary case has a high similarity exceeding the first threshold (70 in this case). As indicated in  FIG. 7B , the similarity to fixed phrase B 2  is kept low without exceeding the first threshold. The first threshold has a value that is not limited to this exemplary case and may alternatively be more or less than 70. 
     S 407 : When the similarity is determined as exceeding the first threshold, translation unit  114  sets, to “one”, the candidate fixed phrase flag for the fixed phrase having values of the similarity determined as exceeding the first threshold. Any fixed phrase having the candidate fixed phrase flag already set to “one” in step S 406  may skip comparison between the similarity and the first threshold. 
     S 408 : Translation unit  114  determines whether or not calculation of the similarity between the target character string and all the fixed phrases has already completed. The process flow returns to step S 405  if the calculation has not yet completed, for repeated processing until calculation of the similarity to all the fixed phrases completes. The process flow proceeds to step S 409  in  FIG. 5B  if the calculation of the similarity between the target character string and all the fixed phrases has already completed. 
     S 409 : Translation unit  114  determines whether or not all the fixed phrases having calculated the similarity to the target character string include any fixed phrase having the candidate fixed phrase flag set to “one”. The process flow proceeds to step S 410  if there is no fixed phrase having the candidate fixed phrase flag set to “one”. The process flow proceeds to step S 412  if there is any fixed phrase having the candidate fixed phrase flag set to “one”. 
     S 410 : Translation unit  114  determines whether or not the “terminal position” of the target character string is located at the end of the input character string. The process flow proceeds to step S 411  if the terminal position is not located at the end of the input character string. The process flow ends if the terminal position is located at the end of the input character string. If the similarity to each of the fixed phrases does not exceed the first threshold, there will be no fixed phrase entirely or partially matching the input character string. In this case, translation unit  114  may be configured to translate the input character string by means of ordinary machine translation, or may be configured to translate with reference to the fixed phrase having the maximum similarity at this stage. 
     S 411 : Translation unit  114  adds one to the value of the “terminal position” of the target character string. The process flow then returns to step S 405  in  FIG. 5A  for calculation of the similarity between the target character string having such a changed terminal position and each of the fixed phrases. The value added to the terminal position is not limited to one but may alternatively be a predetermined number more than or equal to two. This causes accuracy of sentence division to change by the unit of the predetermined number, but reduces the number of times of the similarity calculation. 
     S 412 : if there is determined as being any fixed phrase having the candidate fixed phrase flag set to “one” in step S 409 , translation unit  114  determines whether or not the similarity of each of such fixed phrases is less than a second threshold. The process flow proceeds to step S 414  if the similarity is determined as being less than the second threshold, and proceeds to step S 413  if the similarity is determined as being not less than the second threshold. 
     The second threshold is less than the first threshold by at least a predetermined value. If the similarity before reaching the first threshold achieves high possibility of match with a fixed phrase and then decreases due to continuous mismatch with subsequent characters to become less than the second threshold, a character string having the maximum similarity is assumed as matching the fixed phrase. 
     For example, target character string A 18  in  FIG. 6  has a similarity to fixed phrase B 1  gradually decreasing from a seventeenth character, as indicated in  FIG. 7A . Such a decreasing tendency is determined to specify a division point of the input character string as to be described later. The second threshold (60 in this case) serves as a criterion value for the decrease tendency. 
     The second threshold has a value that is not limited to this exemplary case and may alternatively be more or less than 60. 
     If there is any fixed phrase higher in the similarity than the fixed phrase having the similarity determined as being less than the second threshold in this step, the process flow may alternatively proceed to step S 413  instead of step S 414 . Assume an exemplary case where there are two fixed phrases, namely, a first fixed phrase meaning “Please stow your baggage in the compartment above the seats.” and a second fixed phrase meaning “Please stow your baggage in the compartment above your feet. Passengers in the economy class can stow your baggage also under the seat in front of you.”, and utterance includes a sentence identical to the second fixed phrase. 
     The similarity of the first fixed phrase becomes maximum when a character string until the end of the first fixed phrase is processed, and then gradually decreases to become less than the second threshold at a certain stage. In contrast, the similarity of the second fixed phrase is more than or equal to the second threshold when the similarity of the first fixed phrase becomes less than the second threshold, and keeps increasing. The second fixed phrase has an eventual maximum value of the similarity more than a maximum value of the similarity of the first fixed phrase. 
     In this manner, the second fixed phrase, which is preferably selected, may not be selected because the first fixed phrase satisfies conditions earlier. In order to prevent this for highly accurate translation, even when the similarity is detected as being less than the second threshold in step S 412 , there is provided an additional second condition “the process flow proceeds not to step S 414  but to step S 413  for continuous calculation and comparison of the similarity if there is any candidate higher in the current similarity (for the character string length) than a target candidate fixed phrase”. 
     S 413 : Translation unit  114  determines whether or not the “terminal position” of the target character string is located at the end of the input character string. The process flow proceeds to step S 414  if the “terminal position” is located at the end of the input character string, whereas the process flow proceeds to step S 411  if the “terminal position” is not located at the end of the input character string. 
     S 414 : Translation unit  114  selects a fixed phrase having the maximum similarity from the fixed phrases each having the candidate fixed phrase flag set to “one” (similarity determination processing). Translation unit  114  then acquires translation of this fixed phrase to execute translation processing. 
     S 415 : Translation unit  114  compares an end position of the input character string with the head position+n. The process flow ends if the end position of the input character string is less than, in other words, ahead of, the head position+n. The process flow proceeds to step S 416  if the end position of the input character string is more than or equal to, in other words, identical to or behind, the head position+n. 
     S 416 : Translation unit  114  sets, as the terminal position, a character position of the target character string achieving the maximum similarity, and sets a subsequent head position to a value obtained by the terminal position+1 (division processing). 
     Assume an exemplary case where fixed phrase B 1  is selected for text T 10  (step S 414 ). As indicated in  FIG. 7A , the similarity becomes maximum at the sixteenth character. A character position obtained by adding one to this character position (terminal position) is thus set as a new “head position”. The head position of subsequent text T 12  is accordingly set as the new head position. 
     S 417 : Translation unit  114  resets all the candidate fixed phrase flags to zero. The process flow then returns to step S 404 . Translation unit  114  then applies similar processing to a divided character string. 
       FIG. 8A  and  FIG. 8B  are charts indicating calculation result data of the similarity of each of the fixed phrases to text T 10 . Each chart has a column “maximum value of similarity” indicating a maximum value of the similarity to each of the fixed phrases. The chart further has a column “character position achieving maximum value” indicating the terminal position of the character string of the similarity having the maximum value corresponds to what order number of character from the first character of the input character string. The chart also has a column “current value of similarity” indicating a latest value of the similarity. The chart still further has a column “current character position” indicating the latest value corresponds to what order number of character from the first character of the input characters. 
     According to the data indicated in  FIG. 8A , the similarity calculation has finished for first to twentieth characters, but processing will continue because the current value (73 in this case) of the similarity of fixed phrase B 1  has not become less than the second threshold (60 in this case) (S 412  (No)→S 413  (No)→S 411 →S 405  to S 412 ). The current value of the similarity is updated each time the similarity is calculated for an increased target character string. The maximum value of the similarity is updated when the current value of the similarity exceeds the recorded maximum value of the similarity. If the current value exceeds the first threshold (70 in this case), the fixed phrase flag is changed to one (S 407 ). 
     According to the data indicated in  FIG. 8B , the similarity calculation has finished for first to twenty second characters, where the current value of the similarity of each of the fixed phrases becomes less than the second threshold 60, so that the similarity calculation ends. That is, matching unit  1143  ends the similarity calculation when the similarity becomes less than the second threshold. Fixed phrase B 1  of the similarity having the maximum value is selected to acquire translation “Thank you for boarding.” as a translation (S 412  (Yes) to S 414 ). If two or more candidate fixed phrase flags are set to “one”, a fixed phrase of the maximum similarity having a largest value is selected. 
     Other Exemplary Processing 
     Translation unit  114  is also configured to execute the following processing. 
     When the input character string includes a phrase portion included in none of the fixed phrases, such a phrase portion has a low value of the similarity. Assume an exemplary case where a character string meaning “Please fasten your seat belt securely around your hips.” is selected as fixed phrase B 3  having the maximum similarity for input character string T 20  meaning “Please fasten your seat belt tight around your hips.” as in  FIG. 9 . In this case, the portion meaning “tight” in the input character string does not match the portion meaning “securely” in the fixed phrase. As in exemplarily indicated in a graph in  FIG. 9 , the similarity accordingly varies by once exceeding the first threshold, becoming less than the first threshold, and exceeding the first threshold again. 
     Translation unit  114 , however, continues calculation of the similarity even when the similarity decreases halfway because the similarity does not become less than the second threshold. The similarity thus increases again to update the maximum value. 
     In such a case where the input character string includes a halfway phrase portion not included in the fixed phrases, the similarity once exceeds the first threshold, then becomes less than the first threshold, and increases again to exceed the first threshold, to have two or more maximum points exceeding the first threshold. Translation unit  114  calculates the similarity to achieve matching with a most similar fixed phrase if there is included difference (noise) of such a phrase portion that is not long. If the phrase portion is long, the input character string is divided when the similarity becomes less than the second threshold, for achievement of appropriate division processing. Translation processing executed by translation unit  114  thus achieves translation with reference to a fixed phrase even when a character string includes a plurality of sentences or words partially different from the fixed phrase. 
     1-3. Features and Others 
     In translation unit  114  of translation device  110  according to the exemplary embodiment described above, character string output unit  1141  outputs a plurality of character strings (a plurality of target character strings) each configuring at least part of text in the first language and including a head character of the text, in order of character string length. Matching unit  1143  calculates a similarity between each of the character strings and a fixed phrase in order of character string length. Similarity determiner  1144  selects a fixed phrase having a maximum similarity from fixed phrases having calculated similarity values exceeding the first threshold. Division processor  1145  divides the text at a position achieving the maximum similarity among values of the similarity exceeding the first threshold. This configuration thus achieves significant reduction in amount of calculation for matching processing with the fixed phrases and division processing. Even in a case where input text includes a plurality of sentences, the text is divided at an appropriate point for continuous matching processing with the fixed phrases, achieving higher speed of translation processing. This configuration further enables matching and similarity determination for each fixed phrase, without need for preliminary storage of a plurality of combinations of fixed phrases. This achieves reduction in size of the storage such as database. 
     Other Exemplary Embodiments 
     The first exemplary embodiment has been described above to exemplify the techniques disclosed in the present application. The techniques according to the present disclosure are not limited by the exemplary embodiment, and are applicable to other exemplary embodiments achieved through change, replacement, addition, elimination, or the like where appropriate. Furthermore, constituent elements and functions according to the first exemplary embodiment can be combined to obtain new exemplary embodiments. 
     Such other exemplary embodiments will be described below. 
     [1] 
     The above exemplary embodiment provides translation through acquisition of translation of the fixed phrase most similar to the input character string. The input character string is thus translated in accordance with the fixed phrase even if there is included a phrase portion different from the fixed phrase. Translation unit  114  may alternatively be configured to freely translate such a phrase portion different from the fixed phrase. 
     Assume an exemplary case of input character string T 30  meaning “Hello everybody, thank you for boarding today.” as in  FIG. 10 . Initial character string T 31  meaning “Hello everybody” does not have any relevant fixed phrase in this case and fails to acquire translation through calculation of the similarity. In view of this, translation unit  114  executes the predetermined translation processing described above ( FIG. 5A  and  FIG. 5B ), to divide input character string T 30  into character string T 31  and character string T 32 . These divided sentences are then compared with fixed phrase B 4 , for determination of a different portion (i.e. character string T 31 ). Translation unit  114  may alternatively be configured to apply ordinary machine translation to the different portion and output a translation result along with translation with reference to the fixed phrases. In other words, translation processor  1146  may alternatively be configured to translate into the second language without reference to the fixed phrases, the portion (character string T 31 ) irrelevant to the fixed phrases, in the divided text. 
     [2] 
     According to the above exemplary embodiment, the similarity is unlikely to increase by being affected largely by extremely long utterance that is irrelevant to the fixed phrases. In order to prevent this, the first threshold may be decreased or a section having values of the similarity substantially equal to zero may be deleted, for higher accuracy in matching with the fixed phrases. 
     [3] 
     Translation unit  114  according to the above exemplary embodiment executes processing of matching between each acquired character string and each fixed phrase. The present disclosure is not necessarily limited to this configuration. When there is at least predetermined difference between the similarity values calculated for a plurality of fixed phrases, matching processing may be executed while excluding any fixed phrase of the similarity having a value less than a predetermined value. Specifically, when the similarity of a first fixed phrase and the similarity of a second fixed phrase have difference exceeding a predetermined value, matching unit  1143  may alternatively be configured to end calculation of the similarity of the remaining fixed phrases. This configuration achieves reduction in amount of calculation for matching processing. 
     Still alternatively, when there are at least a predetermined number of fixed phrases having the similarity exceeding the first threshold, matching processing may not be applied to the remaining fixed phrases. Further alternatively, when a predetermined fixed phrase has the similarity achieving 100 or a value close to 100, matching processing may be ended and translation processing may be executed with reference to this fixed phrase. 
     [4] 
     Each of the fixed phrases according to the above exemplary embodiment may alternatively have weighing information added to the similarity in accordance with the number of characters. Specifically, matching unit  1143  may be configured to add a weight to the similarity in accordance with length of each of the fixed phrases. In this case, a value of the weight is determined such that fixed phrases having smaller numbers of characters have a higher similarity. Such similarity additionally having a tendency according to the length of the character string of each of the fixed phrases is likely to increase even for a fixed phrase having a small number of characters. This leads to increase in speed of similarity determination processing. 
     [5] 
     The above exemplary embodiment includes matching processing with all the fixed phrases. The present disclosure is not necessarily limited to this configuration. As described above, the fixed phrases are categorized into groups of different scene information. Scene determination may thus be executed for processing of matching, similarity determination, division, and translation with prioritized reference to fixed phrases relevant to the scene information thus determined. Specifically, fixed phrase acquisition unit  1142  may be alternatively configured to acquire a fixed phrase adapted to a current scene among a plurality of fixed phrases. In this case, translation unit  114  specifies the current scene and applies the translation processing depicted in  FIG. 5A  and  FIG. 5B  to the fixed phrase adapted to the specified scene. 
     The current scene may be specified through input operation by a cabin crew or through scene determination executed by server device  10 . Server device  10  may be configured to determine the current scene in accordance with information transmitted from an operation system or the like (e.g. altitude information, speed information, door open/close information, or time information). 
     [6] 
     Translation unit  114  according to the above exemplary embodiment is configured to output the target character strings including characters (including Chinese characters) sequentially increased one by one from the head of the input character string of text, and match with the fixed phrases. The present disclosure is not necessarily limited to this configuration. Matching can alternatively be applied to a predetermined unit appropriate for a target language or an adopted voice recognition method, such as characters forming a phoneme, each word, or each alphabetical character. 
     The target character strings output for matching processing are not limitedly sequentially increased by a predetermined unit from the head of the input character string, but may alternatively be extracted by units varied in number of characters or the like. 
     [7] 
     The above exemplary embodiment provides the second threshold for determination of a decreasing tendency of the similarity and specification of a character position (achieving the similarity having the maximum value) as a division point for division processing. The present disclosure is not necessarily limited to this configuration. The second threshold may not be provided and division processing may alternatively be executed when a decreasing tendency continues for a predetermined period (e.g. the number of characters). 
     [8] 
     Translation device  110  is not limitedly utilized in an aircraft. Translation device  110  can alternatively be installed and applied where translation with reference to fixed phrases is available, such as guidance at an airport, different public transport, a restaurant, a hospital, or an accommodation. 
     Translation device  110  may still alternatively be provided to a computer terminal. In this case, translation processing may be applied to data input by means of voice or text (after voice is subjected to voice recognition processing), and a translation result may be output via a speaker or a display. 
     [9] 
     The translation processing ( FIG. 5A  and  FIG. 5B ) according to the above exemplary embodiment is not limited to the above exemplary embodiment in terms of the order of execution. Alternatively, the processing may partially be executed parallelly or may be executed in a different order without departing from the scope of the present disclosure. 
     [10] 
     The above exemplary embodiment includes inputting voice data according to utterance. The present disclosure is not necessarily limited to this configuration. Alternatively, text may be acquired via the input interface from an input unit such as a touch panel or a keyboard, or may be acquired via the communication interface from an external device, and translation unit  114  may apply translation processing to the text. 
     [11] 
     Translation device  110  or translation unit  114  according to the present disclosure is not limitedly embodied in accordance with any one of the above exemplary embodiments. A translation method and a computer program executed by translation device  110  or translation unit  114 , and a computer-readable recording medium including the program are included in the scope of the present disclosure. Examples of the computer-readable recording medium include a flexible disk, a hard disk, a compact disc read-only memory (CD-ROM), a magneto-optical disk (MO), a digital versatile disc (DVD), a DVD-ROM, a DVD-RAM, a Blu-ray (registered trademark) disc (BD), and a semiconductor memory. 
     The computer program is not limitedly recorded on the recording medium and may alternatively be transmitted via a network or the like represented by an electric communication line, a wireless or wired communication line, or the Internet. 
     INDUSTRIAL APPLICABILITY 
     The present disclosure is applicable to a translation device or a translation method. 
     REFERENCE MARKS IN THE DRAWINGS 
     
         
           1 : system 
           10 : server device 
           11 : CPU 
           12 : ROM 
           13 : RAM 
           14 : input interface 
           15 : output interface 
           16 : communication interface 
           17 : storage unit 
           20 : display device 
           21 : CPU 
           22 : ROM 
           23 : RAM 
           25 : output interface 
           26 : communication interface 
           27 : memory 
           28 : input unit 
           29 : display 
           30 : microphone 
           40 : speaker 
           110 : translation device 
           111 : voice acquisition unit 
           112 : voice recognizer 
           113 : text generator 
           114 : translation unit 
           115 : translation result output unit 
           1141 : character string output unit 
           1142 : fixed phrase acquisition unit 
           1143 : matching unit 
           1144 : similarity determiner 
           1145 : division processor 
           1146 : translation processor