Background technique
Parking lot is an extremely important ring in static traffic management, carries out the planning, operation, management of park construction,
The parking demand of vehicle can utmostly be met, reduce parking offense, promote road traffic efficiency., whereas if without root
It is averaged turnover rate, averagely stop duration, the parking characteristic customization pipe appropriate such as day part parking stall occupation rate according to the berth in parking lot
Reason strategy, on the one hand will cause parking difficulty problem and is difficult to be effectively relieved;On the other hand, if Public parking area is excessive or charged
Height leads to the waste of fund and land resource it will cause parking lot utilization efficiency is not high, influences society, expanding economy.Cause
This, Accurate Prediction Parking feature has emphatically parking lot of making rational planning for, formulation charge operation management strategy appropriate
Big meaning.
The prediction technique of parking demand has parking generation rate model, land used and Traffic Impact Analysis model, polynary time at present
Return analysis prediction model and the relevant parameter of model is planning, design with building parking demand standard etc., but in existing method
Personnel obtain from professional standard, specification or according to model recurrence, can not reflect to adaptation to local conditions different proposed regions, different land use
The complicated factors bring such as population, economy of property influences, and actual conditions often have deviation.Meanwhile the prior art can not
The accurate influence for considering Car park payment strategy for parking demand is unable to satisfy parking lot network operator and is formulating parking receipts appropriate
Take demand when strategy.
Such as Chinese patent CN 103093643A discloses a kind of method of determining Public Parking Berth number, utilizes
The method that BP neural network determines Public Parking Berth number.Its neural network input layer considered includes population, GDP, family
Front yard is averaged monthly income and family is averaged car number, output layer is the Berth number for planning parking lot.But this mode only can determine that
The berth number in parking lot, and it is unpredictable with the operation in built parking lot, the relevant berth of management, pricing strategy it is average
The characteristic parameters such as turnover rate, duration of averagely stopping, average parking stall occupation rate.
For another example Chinese patent CN 102867407A discloses a kind of parking lot effective berth occupation rate multistep forecasting method,
It utilizes wavelet neural network-maximum lyapunov exponent method combination forecasting, to parking lot effective berth occupation rate
Carry out multi-step prediction.But this mode can only carry out the prediction of berth occupation rate to a certain specific, built parking lot,
The parking feature in the parking lot of the different zones in planning can not be carried out pre- according to the Land character in the proposed region in parking lot
It surveys.
Summary of the invention
It is an object of the present invention to overcome the above-mentioned drawbacks of the prior art and provide one kind to be based on neural network
Public Parking parking facilities' forecasting method.
The purpose of the present invention can be achieved through the following technical solutions:
A kind of Public Parking parking facilities' forecasting method neural network based, comprising:
Step S1: the demand characteristic value of each sample period and the data of corresponding each influence factor and to be predicted are acquired
The data of each influence factor of period, wherein the demand characteristic value include parking lot berth be averaged turnover rate, averagely stop when
Long and day part is averaged parking stall occupation rate;
Step S2: the data of each influence factor of normalized;
Step S3: the normalization data of the demand characteristic value of each sample period and corresponding each influence factor uses prediction
Neural network is trained and verifies;
Step S4: the normalization data of each influence factor of period to be predicted is inputted into trained neural network, is obtained
The demand characteristic value of period to be predicted.
The influence factor includes 500 meters of periphery land-use style, 500 meters of periphery range job sum, 500 meters of periphery
Range residential home sum, 500 meters of periphery range family be averaged annual income, in 1000 range of periphery parking position it is total, to pre-
Parking lot is surveyed to park quantity, parking fee collective system standard to be predicted, park construction type to be predicted.
The neural network includes input layer, hidden layer and output layer, and the input layer includes 8 neurons, described defeated
Layer includes 3 neurons out, and the activation primitive of the hidden layer is Sigmoid function, and the neuron number of hidden layer are as follows:
Wherein: m is input layer number, and n is output layer neuron number, and α is constant, value range 1-10.
The Sigmoid function is smooth curve function, mathematic(al) representation are as follows:
Wherein: f (x) is the output of implicit layer unit, and x is the input of implicit layer unit.
The training process of neural network specifically includes in the step S3:
Step S31: initialization connection weight;
Step S32: choosing one group of sample from training set, using the demand characteristic value of the sample period as target sample,
Using the normalization data of corresponding each influence factor as input sample, it is supplied to neural network;
Step S33: with the input of input sample, connection weight and its threshold calculations hidden layer each unit, then pass through
The output of Sigmoid function calculating hidden layer each unit;
Step S34: it is missed using the response computation output layer each unit generalization of neural network object vector and each neuron
Difference;
Step S35: hidden layer each unit is calculated using the output of connection weight, the generalized error of output layer and hidden layer
Generalized error;
Step S36: adaptive regularized learning algorithm rate;
Step S37: each connection weight and its threshold value are corrected based on adaptive regularized learning algorithm rate;
Step S38: randomly selecting next group of training sample vector and be supplied to network, returns to step S33, until network is complete
Office's error function E is less than preset value, or if the number of iterations N reaches the upper limit;
Step S39: exporting the connection weight of each memory, and training terminates.
The step S36 is specifically included:
Step S361: the correction value of connection weight is calculated:
Wherein: Δ W (N) is the correction value of connection weight when iv-th iteration calculates, EpFor the side of actual value and desired output
Difference, W are the correction value of connection weight, and η is factor of momentum, and α is learning rate, and N is current iteration number;
Step S362: learning rate is calculated:
α (N)=α (N-1)+Δ α (N)
Wherein: Δ α (N) is the incrementss of learning rate when iv-th iteration learns, and α (N) is when iv-th iteration learns
Learning rate, a are the learning rate incrementss upper limit, and b is that learning rate increases coefficient of discharge, when α (N-1) is the N-1 times iterative learning
Habit rate, E (N) are training error.
Compared with prior art, the invention has the following advantages:
1) it can be used for different zones, be able to reflect the Public Parking parking demand that Car park payment influences parking demand
Prediction.
2) eight kinds of influence factors are introduced, and devise 8 corresponding input layers, improve the sophistication of data.
3) momentum term and automatic adjusument learning rate are increased to improve to algorithm, accelerates convergence process, improves and learns
Practise speed.
Specific embodiment
The present invention is described in detail with specific embodiment below in conjunction with the accompanying drawings.The present embodiment is with technical solution of the present invention
Premised on implemented, the detailed implementation method and specific operation process are given, but protection scope of the present invention is not limited to
Following embodiments.
A kind of Public Parking parking facilities' forecasting method neural network based, as shown in Figure 1, comprising:
Step S1: the demand characteristic value of each sample period and the data of corresponding each influence factor and to be predicted are acquired
The data of each influence factor of period, wherein demand characteristic value include parking lot berth be averaged turnover rate, averagely stop duration and
Day part is averaged parking stall occupation rate;
The required data for obtaining influence factor include that 500 meters of periphery land-use style, 500 meters of periphery range job are total
Parking pool in number, 500 meters of periphery range residential home are total, 500 meters of periphery range family is averaged annual income, 1000 range of periphery
Position is total, parking lot to be predicted is parked quantity, parking fee collective system standard to be predicted, park construction type to be predicted;In acquisition
The data of factor are stated, and split data into training data group and prediction data group.
Wherein, 500 meters of periphery land-use style with a size be 1 × 5 land-use style matrix [a1, a2, a3, a4,
A5] it indicates, wherein a1-a5 respectively indicates business management shop (not including dining room) quantity within the scope of 500 meters of periphery, dining room number
Amount, school's number, hospital's number, movie theatre number.
Wherein, the parking fee collective system standard that need to be predicted with a size be 1 × 6 Car park payment matrix [b1, b2,
B3, b4, b5, b6] it indicates, wherein b1-b6 respectively indicates the parking rate that the parking lot predicted on demand is currently set, vehicle
Toll amount at the Parking 30 minutes, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours.
Wherein, the construction type in the parking lot of need prediction is self-propelled Surface parking lots, self-propelled underground parking
Library, full-automatic mechanical parking building, semi automatic machine parking building, self-propelled spatial parking building, this one of six kinds of trackside berth.
Wherein, the mode for obtaining above-mentioned data includes on-site inspection, web crawlers extraction POI data, consults related official
Statistical yearbook etc..
It is corresponding, as shown in Fig. 2, the improved BP neural network used in the application includes input layer, hidden layer and defeated
Layer out, input layer include 8 neurons, and output layer includes 3 neurons, and the activation primitive of hidden layer is Sigmoid function, and
The neuron number of hidden layer are as follows:
Wherein: m is input layer number, and n is output layer neuron number, and α is constant, value range 1-10,
It is specifically determined by network training.
Sigmoid function is smooth curve function, mathematic(al) representation are as follows:
Wherein: f (x) is the output of implicit layer unit, and x is the input of implicit layer unit.
Step S2: the data of each influence factor of normalized, the process can use the life of the mapminmax in Matlab
It enables and realizing;
Step S3: the normalization data of the demand characteristic value of each sample period and corresponding each influence factor uses prediction
Neural network is trained and verifies, as shown in figure 3, wherein the training process of neural network specifically includes:
Step S31: initialization connection weight;
Step S32: choosing one group of sample from training set, using the demand characteristic value of the sample period as target sample,
Using the normalization data of corresponding each influence factor as input sample, it is supplied to neural network;
Step S33: with the input of input sample, connection weight and its threshold calculations hidden layer each unit, then pass through
The output of Sigmoid function calculating hidden layer each unit;
Step S34: it is missed using the response computation output layer each unit generalization of neural network object vector and each neuron
Difference;
Step S35: hidden layer each unit is calculated using the output of connection weight, the generalized error of output layer and hidden layer
Generalized error;
Step S36: adaptive regularized learning algorithm rate, i.e. improved BP and the improvements of former BP neural network exist
In increasing momentum term and automatic adjusument learning rate to improve to algorithm, accelerate convergence process, improve pace of learning.
Wherein, the stability of algorithm can be increased using momentum arithmetic with the acute variation in smooth gradient direction, accelerates net
The convergence rate of network.After increasing momentum term, modified weight amount added the memory in relation to last moment weight modification direction, that is, work as
Between the moment modification direction be last moment modify direction and current time direction combination,
It is specific:
Step S361: the correction value of connection weight is calculated:
Wherein: Δ W (N) is the correction value of connection weight when iv-th iteration calculates, EpFor the side of actual value and desired output
Difference, W are correction value, and η is factor of momentum, and α is learning rate, and N is current iteration number;
Step S362: automatic adjusument learning rate refers in the training process, when iv-th iteration learns, if first N-1 times changes
Learning rate α (N-1) when generation study unanimously tends to training error E (N) decline, then α (N) is intended to increase;Conversely, if consistent
It must tend to increase training error E (N), then α (N) tends to reduce;When training error is constant, learning rate is remained unchanged,
Specifically, calculating learning rate:
α (N)=α (N-1)+Δ α (N)
Wherein: Δ α (N) is the incrementss of learning rate when iv-th iteration learns, and α (N) is when iv-th iteration learns
Learning rate, a are the learning rate incrementss upper limit, and b is that learning rate increases coefficient of discharge, when α (N-1) is the N-1 times iterative learning
Habit rate, E (N) are training error.
Step S37: each connection weight and its threshold value are corrected based on adaptive regularized learning algorithm rate;
Step S38: randomly selecting next group of training sample vector and be supplied to network, returns to step S33, until network is complete
Office's error function E is less than preset value, or if the number of iterations N reaches the upper limit;
Step S39: exporting the connection weight of each memory, and training terminates.
Using gradient descent method adjustment hidden layer to input layer and input layer to the weight of hidden layer, pass through Matlab tool
Traingdm order is realized in case.
Wherein, allowable error range value set by the error can be ± 5%, ± 10%, ± 15%, ± 20%
It is equivalent.The calculation method of error are as follows:
Wherein
Parking demand characteristic value refers to that the berth in the parking lot is averaged turnover rate, averagely stop duration and day part parking stall average occupancy
3 characteristic values.
Wherein, day part parking stall average occupancy is by (06:00-11:00), noon (11:00-16:00), night between morning
(17:00-22:00), the late into the night (22:00-06:00) are divided into four periods.
Step S4: being input to trained improved BP for the data that prediction data is concentrated, every in step S1
A influence factor for influencing Public Parking parking demand corresponds to 1 neuron of improved BP input layer, input layer
Data the data of hidden layer are generated by the processing of S type function, imply layer data and generated by the processing of linear transfer function
The data of output layer, i.e. berth be averaged turnover rate, averagely stop 3 duration, day part parking stall average occupancy data.