with reference to the drawings , one embodiment of the present invention will now be described . in all figures for illustrating the embodiment , the same element or component is basically assigned with the same reference sign , and its repetitive description will be omitted . fig1 is a diagram depicting one example of a system configuration realizing a quantitative plan simulation , according to one embodiment of the present invention . the quantitative plan simulation system according to the embodiment depicted in fig1 comprises a terminal 1 which is operated by a user so as to perform a quantitative plan simulation , and a server 2 connected to the terminal 1 via a network 3 . the terminal 1 is operable to upload a file comprising one or more spreadsheets , from an input screen displayed on a web browser or the like to the server 2 , and then the server 2 is operable to extract , from among numerical values , mathematical formulas or other kinds of data contained in cells in the one or more spreadsheets , a numerical value and a mathematical formula necessary for a quantitative plan simulation , and perform the quantitative plan simulation based on sensitivity analysis , risk analysis or the like . the terminal 1 is operable to receive a result of the quantitative plan simulation from the server 2 , and display the received result on a web browser or the like . each of the terminal 1 and the server 2 comprises a hardware resource of a commonly - used computer , such as a processor , a memory and a hard disc . as one example , the terminal 1 comprises : a network interface for controlling communications with respect to the server 2 ; a memory storing therein a program for performing a quantitative plan simulation ; a processor functioning as a means to executing the program to realize the quantitative plan simulation ; a storage device , such as a hard disc , for storing therein a variety of data , such as intermediate data during a quantitative plan simulation and data about a result of the quantitative plan simulation ; an input device for inputting various inputs ( input data ) necessary for a quantitative plan simulation ; and a display device for displaying a variety of data , such as an intermediate result and a final result of a quantitative plan simulation . the server 2 may also comprise the same computer hardware resources as those in the terminal 1 . in the quantitative plan simulation system according to the embodiment depicted in fig1 , the terminal 1 is operable to execute a program for primarily performing input - output processing for the quantitative plan simulation system , and the server 2 is operable to execute a program for performing major processing of the quantitative plan simulation . as one example , the terminal 1 is operable to perform processing of : transmitting , to the server 2 , input data such as a name of a file to be uploaded to the server 2 or assumptions necessary for a quantitative plan simulation ; receiving output data such as a processing result , from the server 2 ; and displaying the received output data on a display screen such as a web browser . the server 2 is operable to perform a quantitative plan simulation based on the input data received from the terminal 1 , via the network 3 such as a public line or a dedicated line . as above , the terminal 1 and the server 2 in the quantitative plan simulation system function to fulfill their roles , individually . as another embodiment , it is possible to perform the entire processing for the quantitative plan simulation system in only one of the terminal 1 and the server 2 . as one example , the terminal 1 may execute a program configured to be capable of realizing a quantitative plan simulation in a stand - alone manner without using the network 3 . in this case , the terminal 1 can realize the quantitative plan simulation by itself . in the same manner , the server 2 can realize a quantitative plan simulation by itself . fig2 is a diagram depicting an input screen to be displayed on the quantitative plan simulation system according to this embodiment . as one example , the input screen may be displayed on the display device ( e . g ., monitor ) of the terminal 1 via web browser . a user who operates the terminal 1 can designate an address ( url ) of the quantitative plan simulation system using the web browser , to thereby display an input screen as depicted in fig2 on the terminal 2 . in the embodiment depicted in fig1 , by designating an address ( url ) for accessing the server 2 , the input screen as depicted in fig2 can be displayed on the web browser of the terminal 1 . in another embodiment where the terminal 1 operates as the quantitative plan simulation system in stand - alone mode , the user may designate an address ( url ) for accessing the system in the terminal 1 . together with a location ( path ) of a file comprising a spreadsheet of spreadsheet software such as microsoft excel , the user inputs a file name into an input field 100 of the input screen . then , the terminal 1 is operable to access the file designated by the input file name to read a content of the file , and upload the content to the server 2 via the network 3 . in another embodiment where the terminal 1 serves as the quantitative plan simulation system by itself , the terminal 1 is operable to simply read the content of the designated file without performing the uploading . the forward arrow 10 functions as a button for causing a current screen to shift to the next screen , when clicked by the input device such as a mouse . when the user designates a file name in the form of an absolute path by inputting it into the input field 100 , and then clicks the forward arrow 10 by the input device such as a mouse , the terminal 1 is operable , in response to the click , to display a confirmation screen as depicted in fig3 , on the web browser , to prompt the user to confirm the file content . it is to be understood that the terminal 1 may be configured to perform the uploading in the background while displaying the confirmation screen as depicted in fig3 . fig3 is a diagram depicting the confirmation screen for confirming the content of the read file , in the quantitative plan simulation system according to this embodiment . the confirmation screen displayed on the web browser by the display device ( e . g ., monitor ) of the terminal 1 presents a spreadsheet contained in the read file . thus , the user can confirm the content of the file designated by the input screen depicted in fig2 . the backward arrow 11 functions as a button for causing a current screen to return to the previous screen , when clicked by the input device such as a mouse . specifically , in the case where the file content displayed on the confirmation screen is not a desired one , the user can click the rearward arrow 11 to cause the confirmation screen displayed on the web browser of the terminal 1 as depicted in fig3 to return to the input screen depicted in fig2 , and then input a file name again . the terminal 1 is operable to accept the input of the new file name from the user , and read one or more spreadsheets comprised in the file . when the user clicks the forward arrow 10 on the confirmation screen depicted in fig3 by the input device such as a mouse , the terminal 1 is operable , in response to the clicking , to upload the file to the server 2 , and the server 2 is operable to scan the one or more spreadsheets comprised in the uploaded file . further , the terminal 1 is operable to display a scan result screen depicted in fig4 , on the web browser . in another embodiment where the terminal 1 serves as the quantitative plan simulation system by itself , the above processing performed by the server 2 is entirely performed by the terminal 1 . fig4 is a diagram depicting a scan result display screen for displaying a result obtained by scanning a plurality of spreadsheets contained in a file . for example , in a result display field 102 of the scan result display screen , a scan result , such as a file name , the number of sheets , the number of cells , the number of input cells ( assumption data cells ), the number of calculation cells , and the number of calculation result cells , is displayed . the terminal 1 is operable to receive a scan result from the server 2 , and display the received scan result on the web browser . the server 2 is operable to sequentially transmit a scan result to the terminal 1 , and the terminal 1 is operable to sequentially receive the transmitted scan result and update the items of the result display field 102 in real time , according to the scan result . for example , the terminal 1 may be configured to update the result display field 102 of the scan result display screen in such a manner as to count the number of cells scanned in the server 2 . in this case , the user can confirm a status of scanning of the file . when the user clicks the forward arrow 10 in the confirmation screen depicted in fig4 by the input device such as a mouse , the terminal 1 is operable , in response to the clicking , to display a selection screen depicted in fig8 , on the web browser . fig5 is a flowchart depicting a flow of processing for scanning cells in a spreadsheet to identify and store all numerical values and mathematical formulas usable in a quantitative plan simulation . in the quantitative plan simulation system according to this embodiment depicted in fig1 , a quantitative plan simulation program is executed by the processor of the server 2 so as to enable the server 2 to perform the processing depicted in fig5 . in another embodiment where the terminal 1 functions as the quantitative plan simulation system by itself , the terminal 1 is operable to perform the processing depicted in fig5 . for example , in microsoft excel , a book - type file ( hereinafter referred to simply as “ book ”) comprises one or more spreadsheets . the processing depicted in fig5 is designed to repeat the steps of : selecting one of the one or more spreadsheets comprised in the book ; scanning a plurality of cells in the selected spreadsheet ; and identifying respective contents of the scanned cells , until there is no longer any spreadsheet selectable from the book , to thereby exhaustively scan all of the cells in the one or more spreadsheets contained in the book . in step s 1 , scanning is started from a cell located at a scan start position , e . g ., an uppermost and leftmost position of the selected spreadsheet . specifically , the scanning of the cells means read - in of data such as a numerical value , a mathematical formula , a textual character and a blank , as a content of the scanned cell . in step s 2 , it is determined whether the content of the scanned cell is not blank . when the content of the scanned cell is not blank ( s 2 : yes ), the processing routine proceeds to step s 3 . on the other hand , when the content of the scanned cell is blank ( s 2 : no ), the processing routine proceeds to step s 7 . in the step s 7 , the scanned cell is recognized as a blank cell , and the scanning is terminated . in the step s 3 , it is determined whether or not the content of the scanned cell is a numeric character . when the content of the scanned cell is a numeric character ( s 3 : yes ), the processing routine proceeds to step s 4 . on the other hand , when the content of the scanned cell is not a numeric character but merely a textual character ( s 3 : no ), the processing routine proceeds to step s 8 . in the step s 8 , the scanned cell is recognized as a textual character cell , and the scanning is terminated . in the step s 4 , it is determined whether the content of the scanned cell is a mathematical formula or a numerical value . when the content of the scanned cell is a mathematical formula ( s 4 : yes ), the processing routine proceeds to step s 5 . on the other hand , when the content of the scanned cell is not a mathematical formula but a numerical value ( s 4 : no ), the processing routine proceeds to step s 9 . in the step s 5 , it is determined whether the content of the scanned cell determined as a mathematical formula is used in an additional calculation . when the mathematical formulas is referenced by other mathematical formulas ( s 5 : yes ), the processing routine proceeds to step s 6 . in the step s 6 , the scanned cell is recognized as a calculation cell , and the scanning is terminated . on the other hand , when the mathematical formulas is not referenced by any other mathematical formulas ( s 5 : no ), the processing routine proceeds to step s 12 . in the step s 12 , the scanned cell is recognized as a calculation result cell , and the scanning is terminated . in the step s 9 , it is determined whether or not the content of the scanned cell determined as a numerical value is used in calculation . when the numerical value is referenced by mathematical formulas ( s 9 : yes ), the processing routine proceeds to step s 10 . in the step s 10 , the scanned cell is recognized as an assumption data cell , and the scanning is terminated . on the other hand , when the numerical value is not referenced by any mathematical formula ( s 9 : no ), the processing routine proceeds to step s 11 . in the step s 11 , the scanned cell is recognized as an independent numerical value cell , and the scanning is terminated . after completion of determination on the content of the one scanned cell ( termination of scanning for the one scanned cell ), in step s 13 , it is determined whether or not there is a next cell ( e . g ., a cell located on a right side of the scanned cell ) in the spreadsheet . ( in this determination , when there is no longer any scannable cell in the spreadsheet , and there is an additional spreadsheet selectable from the book , the additional spreadsheet is selected , and a cell located at a scan start position e . g ., an uppermost and leftmost position of the selected spreadsheet , is determined as a next scannable cell ). when there is a next scannable cell ( s 13 : yes ), the processing routine proceeds to step s 14 . in the step s 14 , scanning for the next cell is started . on the other hand , when there is no longer any scannable cell ( s 13 : no ), the processing routine proceeds to step s 15 . in the step s 15 , the thus recognized assumption data cells , calculation result cells and calculation cells are associated with each other based on a reference relationship among numerical values and mathematical formulas corresponding thereto , so as to form a data set for assumption data , and the data set is stored in a database ( e . g ., the storage device of the server 2 ) of the quantitative plan simulation system , together with respective names representing the numerical values and the mathematical formulas . for example , a data set is formed by associating the recognized assumption data cells with the calculation cells and calculation result cells having a reference relationship with the assumption data cells . then , a textual character cell or a function identifier of a mathematical formula located adjacent to each of the assumption data cells , the calculation cells and the calculation result cells in the data set ( e . g ., located at an end , such as an upper end or a lower end , of a table in a spreadsheet ) is automatically associated with a respective one of the cells as a name thereof . alternatively , such a textual character cell or a function identifier of a mathematical formula is presented to a user as a candidate for a name of each of the assumption data cells , the calculation cells and the calculation result cells , and then associated with a respective one of the cells as a name thereof by the user . finally , the data set comprising the assumption data cells , the calculation cells and the calculation result cells each associated with a name thereof is stored in the database . thus , the data set stored in the database can be searched by each of the names of the cells comprised in the data set . further , information such as a name of each of the spreadsheets and a position of each of the cells may be stored in the database in combination therewith . upon completion of the storage in the database in the step s 15 , the processing for scanning cells in the spreadsheets is terminated . fig6 is a flowchart depicting a flow of processing for scanning cells in a spreadsheet to identify and store numerical values and mathematical formulas pertaining to an analysis target index , individually . in the quantitative plan simulation system according to this embodiment depicted in fig1 , the quantitative plan simulation program is executed by the processor of the server 2 so as to enable the server 2 to perform the processing depicted in fig5 . in another embodiment where the terminal 1 functions as the quantitative plan simulation system by itself , the terminal 1 is operable to perform the processing depicted in fig6 . in step s 1 ′, upon selecting an analysis target index according to a user input , the processing routine proceeds to step s 2 ′. in the step s 2 ′, a cell is scanned in which the selected index is calculated . for example , a cell containing a function identifier corresponding to the selected index is searched from one or more spreadsheets comprised in a book , and a cell containing a numerical value or a mathematical formula having a reference relationship with the searched cell is scanned . alternatively , a cell containing a text corresponding to the selected index is searched from one or more spreadsheets comprised in a book , and a cell containing a mathematical formula or a numerical value pertaining to the text is scanned . in step s 3 ′, as regards the cell scanned in the step s 2 ′, it is determined whether or not there is a cell referenced for calculation on the scanned cell . in other words , it is determined whether or not there is a cell containing a numerical value or a mathematical formula referring to the scanned cell . when , as regards the cell scanned in the step s 2 ′, there is a cell referenced by the scanned cell ( s 3 ′: yes ), the processing routine proceeds to step s 4 ′. in the step s 4 ′, a scan target is shifted to the referenced cell ( calculation cell ) to scan the cell . on the other hand , when , as regards the cell scanned in the step s 2 ′, there is no cell referring to the scanned cell ( s 3 ′: no ), the processing routine proceeds to step s 6 ′. in the step s 6 ′, a content input in the cell is recognized as assumption datum , not as a calculation formula , and the analysis on the reference structure of the analysis target index is terminated . in step s 5 ′, as regards the cell scanned in the step s 4 ′, it is determined whether or not there is a cell referenced for calculation on the scanned cell . when there is a referenced cell ( s 5 ′: yes ), the processing routine returns to the step s 4 ′. in the step s 4 ′, the scan target is shifted to the referenced cell ( calculation cell ) to scan the cell . on the other hand , when there is no referenced cell ( s 5 ′: no ), the processing routine proceeds to the step s 7 ′. in the step s 7 ′, as regards the cell scanned in the step s 4 ′, the cell is recognized as assumption datum , and the analysis on the reference structure of the analysis target index is terminated . in step s 8 ′, a list of the initially selected index and all assumption data ( numerical values ) used in calculation thereof ( mathematical formula ) is displayed . the displayed list may be stored in the database . then , the processing for scanning cells in the one or more spreadsheets , individually , is terminated . fig7 is a diagram depicting a calculation structure stored in the database , wherein the calculation structure is composed of numerical values and mathematical formulas and expressed in a tree shape . the quantitative plan simulation system according to this embodiment is operable to graphically present a reference relationship among numerical values and mathematical formulas , in the form of a calculation structure composed of the numerical values and the mathematical formulas . that is , an entirety of a calculation structure necessary for an index designated as a simulation target by a user , i . e ., an entirety of a cause - and - effect relationship among a plurality of pieces of assumption data regarding a result of the calculation , is graphically presented . for example , as depicted in fig7 , after scanning of the one or more spreadsheets , a calculation structure composed of numerical values and mathematical formulas stored in the database is expressed in a tree shape , and displayed , for example , on the web browser of the terminal 1 . thus , the user can easily figure out a cause - and - effect relationship among a plurality of pieces of assumption data . fig8 is a diagram depicting a selection screen for selecting a goal ( target ) of a quantitative plan simulation . a keyword input field 103 is an input field for allowing a user to input a keyword or the like for searching data pertaining to a goal ( target ) of a quantitative plan simulation , from the data set stored in the database . a search button 104 is a button configured to be clicked by an input device such as a pointing device so as to perform searching . for example , when the search button 104 is clicked , the server 2 in the quantitative plan simulation system is operable to search , from the database , a data set having a name at least partially coincident with the keyword input through the keyword input field , and display a result of the search on a selection screen on the web browser of the terminal 1 , in the form of a list . as another embodiment , it is also possible to preliminarily display a list of all data sets stored in the database , on a selection screen , without displaying the keyword input field 103 and the search button 104 . for example , a list including items 105 and 106 is displayed on the selection screen . as the item 105 , an index selectable as a goal of a quantitative plan simulation is displayed . further , as the item 106 , detailed information about the index displayed as the item 105 is displayed . for example , “ npv ” ( net present value ) is displayed as the item 105 , and “ development plan ” and “ d273 ” are displayed , respectively , as a spreadsheet name and a location in the spreadsheet to serve as the item 106 . similarly , “ irr ” ( internal rate of return ) and “ payout time ” are displayed at respective positions corresponding to the item 105 , with former &# 39 ; s detailed information “ sheet name : development plan , location : d351 ” and latter &# 39 ; s detailed information “ sheet name : evaluation summary , location : ab5 ”. a user can select an index to be set as a goal of a quantitative plan simulation , using the selection screen displayed on the web browser as depicted in fig8 . for example , a link to the next screen depicted in fig9 is added to each of the “ npv ”, “ irr ” and “ payout time ” displayed as the item 105 . thus , the user can click the link by an input device such as a pointing device , so as to shift the selection screen to the next screen ( see fig9 ). alternatively , after selecting the index displayed as the item 105 , the screen may be shifted by clicking the forward arrow 10 . fig9 is a diagram depicting an assumption adjustment screen for adjusting an assumption ( input valve ) constituting the selected goal ( target ), in the case where a user selects “ npv ” as a goal of a quantitative plan simulation . the quantitative plan simulation system is operable to read a data set pertaining to “ npv ” from the database , and carry out preparation for performing a simulation ( e . g ., sensitivity analysis and risk analysis ( monte carlo simulation ) as disclosed in the non - patent document 1 ). in the assumption adjustment screen depicted in fig9 , a target value field displays the selected goal ( target value ). in an assumption list 108 , assumptions ( input values ) constituting the goal displayed in the target value field 107 . in an example depicted in fig9 , “ npv ” which is an index selected as the goal and “¥ 495 ” which is a value of npv are displayed in the target value field 107 , and a plurality of assumptions such as “ initial market size ”, “ market growth rate ( 5 years )”, and “ share at peak ”, forming “ npv ” are displayed in the column “ input value name ”. in this case , the quantitative plan simulation system is operable to perform processing of : searching a data set containing a calculation result cell corresponding to “ npv ” selected as the goal , from the database ; reading , as assumptions ( input values ), the contents of the assumption data cells or calculation cells such as “ initial market size ”, “ market growth rate ( 5 years )” and “ share at peak ” contained in the searched data set ; and displaying a list of the assumptions on the assumption adjustment screen . further , in the assumption list 108 , perspective current values of the input values are displayed in the column “ current value ”, and slide bars for adjusting the respective values in the column “ current value ” are displayed in the column “ current value slide bar ”. in the assumption adjustment screen displayed on the web browser of the terminal 1 , a user can laterally displace each of the slide bars in the column “ current value slide bar ” to increase or reduce the current value of each of the assumptions , interlockingly with the displacement of a corresponding one of the slide bars . according to increase / decrease in the current value of each of the assumptions , the quantitative plan simulation system can dynamically perform the simulation . when the user clicks one of the assumption names in the column “ input value name ”, a detailed information display screen ( fig1 ) presenting the information about the clicked assumption is displayed . fig1 is a diagram depicting the detailed information display screen displaying information about the assumptions ( input values ). for example , the assumption “ initial market size ” is clicked , a detailed information display screen 109 is inserted and displayed between the “ initial market size ” and the “ market growth rate ( 5 years )” just below the “ initial market size ” in the assumption list 108 . in the detailed information display screen 109 , related information such as user &# 39 ; s comments , time - series data or a graph can be displayed as information about the “ initial market size ”. when the user clicks the forward arrow 10 , the server 2 in the quantitative plan simulation system is operable , in response to the click input , to perform the simulation . as a result , a screen as depicted in fig1 is displayed on the web browser of the terminal 1 . fig1 is a diagram depicting a tornado chart display screen for displaying a result obtained by performing sensitivity analysis based on the assumptions ( input valves ) to each of which a fluctuation range is set using a preset value . the assumptions displayed in the column “ input value name ” in an assumption list 110 are displayed after being re - arranged in descending order ( or ascending order ) of level of sensitivity according to a result of the sensitivity analysis . in an example depicted in fig1 , “ initial price ”, “ manufacturing cost per unit ”, “ falling price rate ( 5 years )” and others are displayed in descending order of level of sensitivity . in the assumption list , a minimum value possibly taken by the assumption is displayed in the column “ low ”, and a maximum value possibly taken by the assumption is displayed in the column “ high ”. for example , the minimum value and the maximum value each possibly taken by the assumption may be appropriately pre - set , respectively , at − 20 % and + 20 % with respect to the current value . the minimum value and the maximum value each possibly taken by the assumption may be appropriately pre - set as mentioned above , so that it becomes possible to cutting out user &# 39 ; s time and effort for setting of assumption data , for example , capable of , only by a click operation without modifying initial data of assumptions , allowing the user to promptly perform simulations for sensitivity analysis and risk analysis . according to adjustment of a slide bar 111 of each of the assumptions , or according to adjustment of the minimum value ( value presented in the column “ low ”) or the maximum value ( value presented in the column “ high ”) by means of manual input or the slide bar , the sensitivity analysis is performed in real time , and a result of the sensitivity analysis is displayed in the column “ current value slide bar ” of the assumption list 108 in the form of a tornado chart . in another embodiment , a tornado chart indicative of the result of the sensitivity analysis may be displayed in another column or on another screen . further , the quantitative plan simulation system may be configured such that , when one of the slide bars 111 for the respective assumption is displaced , resulting alteration of the assumption list 110 , such as re - arrangement of the assumptions in the column “ input value name ”, or a change in the target value ( in this example , the value of npv ), is displayed with an animation effect . an amount of displacement of the slide bar 111 corresponding to each of the assumption is in the range of a preset minimum value ( value of the “ low ”) and a preset maximum value ( value of the “ high ”). in the case where at least one of the value of the “ low ” and the value of the “ high ” is adjusted by means of manual input or the slide bar , the amount of displacement of the slide bar 111 can be altered according to the adjusted the value of the “ low ” and / or the value of the “ high ”. fig1 is a diagram depicting a simulation result display screen for displaying a result obtained by performing risk analysis ( monte carlo simulation ) based on the assumptions ( input valves ). the simulation result display screen depicted in fig1 is displayed in response to clicking the forward arrow 10 in the tornado chart display screen illustrated in fig1 . then , the server 2 in the quantitative plan simulation system is operable , based on the values of the assumptions ( input values ), to perform a monte carlo simulation as risk analysis . on the simulation result display screen , a probability distribution is displayed according to progression of the simulation . in a simulation result table 112 , an expected value and others obtained from a result of the monte carlo simulation are displayed . in the example where npv is selected as the goal ( target value ), “ npv expected value ”, “ expected value attainment probability ” and “ over - zero probability ” are displayed together with numerical values thereof . the monte carlo simulation is continuously run by a constant number of times of running ( e . g ., 10 , 000 cycles or 50 , 000 cycles ) all the time . a value of the calculation result is altered by changing the input value and the value of the “ low ” or the “ high ” by means of the slide bar 111 or manual input . when the input value is changed , the expected value presented in the simulation result table 112 is also updated along with continuation of the running . that is , by continuously running the monte carlo simulation , it becomes possible to dynamically change a result of the risk analysis every time the slide bar or the like is displaced . further , the quantitative plan simulation system may be configured to , only by designating a file name in the input field 100 and clicking the forward arrow 10 : scan all of one or more spreadsheets of a book ; automatically perform a quantitative plan simulation based on scanned assumption data ; and display the result depicted in fig1 or fig1 . this makes it possible to obtain a simulation result by a one - click operation . based on a result of simulations such as sensitivity analysis and risk analysis ( monte carlo simulation ) depicted in fig1 and 12 , the user can make a prediction about the future and easily perform decision - making . the quantitative plan simulation system , method and program of the present invention are usable in the field of quantitative plan simulations for supporting planning and decision - making in management of private - sector institutions and public institutions ( water projects , public transportations , other infrastructure investments , etc .)