US3739163A - Measurement of mean waiting time - Google Patents

Measurement of mean waiting time Download PDF

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Publication number
US3739163A
US3739163A US00105221A US3739163DA US3739163A US 3739163 A US3739163 A US 3739163A US 00105221 A US00105221 A US 00105221A US 3739163D A US3739163D A US 3739163DA US 3739163 A US3739163 A US 3739163A
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Prior art keywords
time
responsive
output
elevator
signals
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T Yuminaka
T Iwasaka
K Hirasawa
K Kawatake
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Hitachi Ltd
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Hitachi Ltd
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    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06G—ANALOGUE COMPUTERS
    • G06G7/00—Devices in which the computing operation is performed by varying electric or magnetic quantities
    • G06G7/12—Arrangements for performing computing operations, e.g. operational amplifiers
    • G06G7/18—Arrangements for performing computing operations, e.g. operational amplifiers for integration or differentiation; for forming integrals
    • G—PHYSICS
    • G04—HOROLOGY
    • G04F—TIME-INTERVAL MEASURING
    • G04F10/00—Apparatus for measuring unknown time intervals by electric means
    • G—PHYSICS
    • G04—HOROLOGY
    • G04F—TIME-INTERVAL MEASURING
    • G04F10/00—Apparatus for measuring unknown time intervals by electric means
    • G04F10/04—Apparatus for measuring unknown time intervals by electric means by counting pulses or half-cycles of an AC
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
    • G06F17/10—Complex mathematical operations
    • G06F17/18—Complex mathematical operations for evaluating statistical data, e.g. average values, frequency distributions, probability functions, regression analysis
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06G—ANALOGUE COMPUTERS
    • G06G7/00—Devices in which the computing operation is performed by varying electric or magnetic quantities
    • G06G7/12—Arrangements for performing computing operations, e.g. operational amplifiers
    • G06G7/20—Arrangements for performing computing operations, e.g. operational amplifiers for evaluating powers, roots, polynomes, mean square values, standard deviation

Definitions

  • An analog integrator AIN begins integration of a constant voltage as each elevator signals his arrival and resets at the next elevator arrival so as to provide an output of a sawtooth waveform.
  • a filter F flattens this sawtooth output to supply a quantity proportional to the mean waiting time.
  • counters are employed to perform the summing operations.
  • the average or mean waiting time is an index for expressing the degree of operation (e.g. travel) service of the elevator system. It is the average or mean value of time lengths (waiting time) during which users wait on a floor from their arrival at this floor until they get on an elevator. Thus, the waiting time differs from user to user. However, it can be said that the shorter the average waiting time is, the better are the conditions of transportation.
  • the mean waiting time Wm of each passenger is represented by where W1, W2 Wi WN indicate the waiting times respectively taken by N passengers before they get on the respective elevators at a floor after their arrivals at the floor.
  • Conventional methods for measuring the mean waiting time comprise such a method in which researchers on respective floors measure the waiting time of users with a stop watch, and such a method in which the lapse of time from the registration ofa hall call from respective floors until an elevator stops at the floor is automatically measured, but they cannot be considered satisfactory. Namely, when researchers are distributed on respective floors, researchers whose number is equal to at least the number of service floors are necessary, provided that one researcher measures the waiting time on one floor. When the numbers of elevators and users are large, the waiting times of respective users can hardly be measured even if the number of researchers is increased.
  • Qm the mean value of the number of persons who are left behind at a floor and who are intending to go in the direction under consideration
  • M the mean value of intervals between elevator arrivals at the floor in the direction under consideration (seconds) (where, the passing of the floor in the direction under measurement because of no registration of the cage or hall call is deemed as an arrival, and the passing of the floor in the direction under measurement because of full capacity is deemed as no arrival);
  • Lm the mean value of the number of persons who are waiting on the floor for an elevator in the direction under measurement, when an elevator arrives at the floor in that direction
  • the mean waiting time for one user can be obtained as follows:
  • the present invention is based on the abovedescribed analysis. More particularly, the mean waiting time in a system in which at least one subject becomes available at time intervals, is measured by taking a quantity corresponding to the ratio of the total sum of squares of said time intervals to the total sum of said time intervals. Said quantity is apparently proportional to the mean waiting time.
  • An object of this invention is to provide a method of estimating or approximately determining the mean waiting time of a user for at least one subject which bemeasuring a second value representative of a sum of the squares of said time intervals and calculating the ratio of the first value to said second value.
  • Another object of this invention is to provide a system for estimating mean waiting time and, in particular, the mean waiting times for users of an elevator system, including a means for producing time interval signals, the intervals of which relate to time intervals of travel service provided by the elevator system, an integrator circuit for integrating a constant input during each interval of the time interval signals, and a filter for smoothing an output of the integrator.
  • the integrator may be an analog form and, in addition, digital circuitry may be employed for counting and summing, subsequent to storage, of a plurality of pulses representative of a plurality of intervals of waiting times.
  • FIG. 1 is a graphic representation of elevator arrivals at a floor
  • FIG. 2 is a circuit diagram of an embodiment of the invention
  • FIG. 3 is a graphical illustration of the operation of the circuit of FIG. 2;
  • FIG. 4 is a block diagram of an embodiment of the invention employing a digital method.
  • FIG. 1 shows intervals T T T,, on a time axis at each end of which upward elevators arrive at the second floor.
  • FIG. 2 shows a system for measuring the average waiting time which comprises an analog integrator AIN and a filter F.
  • the analog integrator includes an operational amplifier OAl, a feedback capacitor CI connected to both ends of the operational amplifier OAI, a switch SWll and a resistor Rll for the resetting operation, and an input resistor R12.
  • the switch SWll closes to establish a closed loop including the resistor R11 and the feedback capacitor CI upon the arrival of an elevator and allows the charge stored in the capaci tor CI to discharge swiftly to reset the analog integrator AIN.
  • the switch SW11 opens immediately after resetting.
  • the analog integrator AIN begins to integrate the input again.
  • the input resistor RT12 is connected another switch SW12 in series therewith which opens when the switch SW11 is closed.
  • To the input resistor R12 is applied an input voltage E through the switch SW12.
  • the output of the analog integrator AIN is supplied to a filter F including an operational amplifier, a feedback capacitor CF, a feedback resistor RF] and an input resistor RF2.
  • the filter F provides an output signal which is the average of the output of the analog integrator AIN.
  • the integration constant giving the gradient of this line can be expressed by:
  • the switch SW1] When the next upward elevator arrives at the floor after a time interval of T, the switch SW1] will close and SW12 will open.
  • the analog integrator AIN is reset immediately after that time, the time required for resetting being not more than about 100 microseconds. Whereas, the intervals between elevator arrivals T, (i 1, 2, 3, n) seldom go below 20 seconds. Thus, the resetting time of said order can almost be neglected. Therefore, the output of the analog integrator AIN will have a sawtooth waveform. Immediately after the resetting operation, the switch SW11 will open and SW12 will close to begin the integration again.
  • the output of the analog integrator AIN will have a sawtooth waveform as shown in FIG. 3, in which the bases are equal to the intervals of elevator arrivals T T T T with a common gradient and hence different height.
  • the mean waiting time is the average or mean value of waiting times in an arbitrarily chosen time period T (T will hereinafter be referred to as the averaging time). So, the larger the time constant of the filter F is, the longer becomes said averaging time. If the time constant of the filter F is selected to be too large, variations in the output of the filter F become so small that the measurement of the desired waiting time becomes impossible. Therefore, the time constant of the filter F should be selected to be appropriate for measuring the mean waiting time in the necessary averaging time T.
  • the time constant of the filter F is selected to have an averaging time T the output X of the filter F represents the average or mean waiting time in the preceding time period T at any time.
  • the time interval T is detected every time an elevator arrives at the floor, but 35 with respect to an elevator which is the subject of the embodiment, a time interval between any two adjacent time periods in which the elevator is available on the floor considered is not represented only by the arrival intervals.
  • departure intervals, intervals of the dooropening operation and intervals of the door-closing operation, etc. also show indirectly the arrival interval of an elevator, i.e., the time interval T, is related to the time interval between the time periods in which an elevator is available.
  • the time intervals under measurement can be arranged to be the time intervals from the departure of an elevator to the arrival of the next elevator, or from the time an elevator closes its door to the time the next elevator opens its door.
  • the overall mean waiting time on a floor can be measured by averaging the mean upward and downward waiting times.
  • FIG. 4 shows a block diagram of another embodiment of the invention employing a digital computation device.
  • a pulse oscillator POS constantly generates pulses of a fixed frequency and supplies its output to AND gates Al and A2.
  • a flip-flop circuit FF inverts the outputs from output terminals 01 and 02 every time an arrival signal RS of an elevator enters the' circuit.
  • Counters CUl and CU2 alternately perform counting operations. More particularly, while the counter CUl counts an 65 input quantity, the counter CU2 supplies a quantity counted in the preceding interval to a squaring device SD to square it and the result is then stored in a register REG. The output of the square device SD is sequentially stored in P1 to PN of the register REG and the stored contents are added by an adder ADD.
  • a divider DV divides the output of said adder ADD by the output of an average time device ATD. Thus, the mean waiting time Wm can be calculated.
  • a starting signal SS is given to an AND gate A3 so as to allow a pulse train to be supplied to the AND gate A1.
  • An arrival signal RS is sent to the flip-flop FF to provide an output signal on the output terminal 02.
  • the AND gate Al remains open during an arrival interval T and the counter CUl counts the pulse train during the time interval T Thus, the calculated value of the counter CUl becomes equal to the arrival interval Tl.
  • the flip-flop FF When a next elevator signal arrival after a time lapse of T the flip-flop FF is inverted by the arrival signal RS to provide an output signal on the output terminal 01 and to provide no output signal on the output terminal 02. Then, the AND gate Al is closed and A2 is opened and the counter CU2 counts the pulse train in the arrival interval T and hence the counted value gives the arrival interval T While the counter CU2 counts the pulse number, the counter CUl supplies the previously counted value T, to the squaring device SD to give T This value T is stored in a portion P, of the register REG. The counter CUl is reset by reset signals REl and RE2 to prepare for the next operation. The counters CUl and CU2 are so arranged that they cannot be reset during the counting operation, i.e. while receiving an input pulse train from the AND gate Al or A2.
  • an arrival signal RS is given to the flip-flop FF again to invert the flipflop, opening the AND gate A1 and closing the AND gate A2.
  • the counter CUl begins a counting operation again and the square of the counted value T by the counter CU2, that is T ⁇ , is stored in a portion P2 of the register REG, as is similar to the foregoing operation.
  • the values T T, are stored in portions Pl, PN of the register REG by a sequence of similar operations.
  • the divider DV can provide an output:
  • the mean waiting time can be measured simply by detecting time intervals T, which are related with the intervals between successive time periods in which said subjects are available.
  • an analog integrator integrates the input during each of said time intervals and in which the integrated output is flattened by a filter
  • the output of the filter may continuously represent an instantaneous mean waiting time
  • a system for estimating the mean waiting time of the waiting times for the users of an elevator system which provides travel services from one to another of a plurality of floors comprising:
  • first means responsive to successive travel services
  • second means responsive to said time interval signals, for integrating an input of a predetermined constant value during each interval of a respective one of said time interval signal, thereby producing, successively output signals each indicative of the integration of said input;
  • third means responsive to the output signals of said second means, for smoothing the output signals of said second means.
  • said first means includes switch means, which in response to each of said successive travel services, permits said input to be supplied to said second means for each said time interval and resets said second means at the end of each said time interval to clear the integration of said input
  • said second means includes an analog integrator which integrates said input
  • said third means includes a filter circuit for smoothing the output signals of said second means.
  • said switch means includes a first switch connected between an input means which produces an output of said predetermined constant value and said analog integrator through an input resistor and a second switch connected between output and input terminals of said analog integrator through a feedback resistor, said first switch being closed for each said time interval and open at the end of said each time interval, while said second switch is open when said first switch is closed and closed when said first switch is open.
  • a system for estimating the mean waiting time of the waiting times for the users of an elevator system comprising:
  • means for generating a signal representative of the waiting times including first means, responsive to a first prescribed condition of an elevator with respect to a given floor, for initiating the generation of a signal representative of the waiting time;
  • third means responsive to a predetermined time period corresponding to a plurality of said waiting time signals, for averaging said waiting time signals over a selected time interval and producing an output signal representative of said average.
  • a system according to claim 4, wherein said first means is responsive to the passage of an elevator, which is available to carry additional passengers, past a prescribed point with respect to a given floor, for initiating the generation of said waiting time signal.
  • said first means is responsive to the departure of an elevator from said given floor, for initiating the generation of said waiting time signal.
  • said second means is responsive to the passage of an elevator, which is available to carry additional passengers, past a prescribed point with respect to a given floor, for terminating the generation of said waiting time signal.
  • said first means comprises a source of reference potential, at first condition responsive switch connected thereto, and an integrator circuit connected to said first switch, said first switch being coupled to connect said source of reference potential to said integrator in response to the occurrence of said first condition, and a second condition responsive switch connected in the feedback circuit provided in said integrator, and being coupled to be opened to the occurrence of said first condition.
  • said third means comprises means for filtering the output of said integrator circuit.
  • said first means comprises a pulse generator
  • a first counter logically coupled to the output of said pulse generator to count pulses supplied therefrom
  • a first gate circuit for initiating the supply of pulses generated by said pulse generator to said counter, in response to a signal representative of the occurrence of said first condition.
  • said second means comprises means for disabling said first gate circuit from supplying pulses to said first counter in response to a signal representative of the occurrence of said second condition whereby the number of pulses counted by said first counter will represent said waiting time signal.
  • said third means comprises a squaring circuit connected to 20 the output of said first counter, a storage register connected to said squaring circuit to store successive outputs thereof representative of the squared values of successive waiting times, an adder circuit connected to the output of said register to sum the contents thereof, a divider circuit having one input connected to the output of said adder circuit, and a timer circuit connected to another input of said divider circuit, said timer circuit supplying a signal representative of the time elapsed from the generation of a selected time interval signal, whereby the output of said divider is representative of the mean waiting time over a preselected time interval.
  • said disabling means includes a flip-flop circuit, the state of the 5 outputs of which are controlled by a signal representative of one of said prescribed conditions, a second gate circuit logically coupled to said pulse generator and one of the outputs of said flip-flop, the other output of said flip-flop controlling said first gate, and a second counter circuit connected to the output of said second gate, the output of said second counter being supplied to said squarer circuit.
  • first means responsive to successive time interval signals for measuring a first value representative of the sum of said time intervals
  • second means responsive to successive time interval signals for measuring a second value representative of the sum of the squares of said time intervals; and third means for calculating the ratio of said second value to said first value.
  • a system for estimating the mean value per user of the waiting times W1, W2, Wi Wn ofa plurality of users in an elevator system including at least one elevator providing transportation of users among a plurality of floors, wherein the users arrive at random at a given one of said floors and wait at the floors for said waiting times in order to receive transportation in a predetermined direction, which transportation becomes available at said given one of said floors at irregular time intervals T1, T2 Ti Tn comprising:
  • first means responsive to successive time interval signals for measuring a first value representative of the sum second means responsive to successive time interval signals for measuring a second value representative of a sum 5 of the squares of said time intervals;
  • third means for calculating the ratio (gm/g7?) of said second value to said first value.
  • first means logically coupled to said pulse generator and responsive to each of said successive signals, for generating respective signals representative of the count of the number of pulses between successive ones of said plurality of successive signals;
  • second means responsive to the output of said first means, for generating a signal representative of the sum of the squares of said count representative signals
  • third means responsive to the output of said second means and a signal representative of a prescribed interval of time, for dividing the output of said second means by said time representative signal, whereby said mean interval of time between said plurality of signals may be determined.

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US00105221A 1970-01-16 1971-01-11 Measurement of mean waiting time Expired - Lifetime US3739163A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0017251A1 (de) * 1979-04-07 1980-10-15 Forschungszentrum Jülich Gmbh Schaltungsanordnung für die Bestimmung der mittleren Periodendauer eines periodischen Signals
WO1999021063A1 (en) * 1997-10-16 1999-04-29 The Victoria University Of Manchester Timing circuit
US6810385B1 (en) * 1999-10-26 2004-10-26 Forecourt Communications Group Method and apparatus using consumer idle time for productive activities
US20090278719A1 (en) * 2008-05-08 2009-11-12 Freescale Semiconductor, Inc. Analog-to-digital converter with integrator circuit for overload recovery

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0017251A1 (de) * 1979-04-07 1980-10-15 Forschungszentrum Jülich Gmbh Schaltungsanordnung für die Bestimmung der mittleren Periodendauer eines periodischen Signals
WO1999021063A1 (en) * 1997-10-16 1999-04-29 The Victoria University Of Manchester Timing circuit
US6434211B1 (en) 1997-10-16 2002-08-13 The Victoria University Of Manchester Timing circuit
AU757820B2 (en) * 1997-10-16 2003-03-06 University Of Manchester, The Timing circuit
US6810385B1 (en) * 1999-10-26 2004-10-26 Forecourt Communications Group Method and apparatus using consumer idle time for productive activities
US20090278719A1 (en) * 2008-05-08 2009-11-12 Freescale Semiconductor, Inc. Analog-to-digital converter with integrator circuit for overload recovery
US7671774B2 (en) * 2008-05-08 2010-03-02 Freescale Semiconductor, Inc. Analog-to-digital converter with integrator circuit for overload recovery

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