According to the three
evaluation indexes selected above, a BP neural network model is constructed,
and the process of establishing the model is shown in Figure 4.

Figure 4: Building BP neural
network model and solving flow chart.
Parameter
setting of BP neural network model
Network layer number: Kolmogorov theorem points out that in theory, three-
layer neural network can fit any continuous nonlinear function. In order to
simplify the model, this paper uses three-layer neural network model [5].
Set input layer: Four evaluation criteria are selected to describe
the product, so the number of input layer neurons is 4.
Number of neurons in the hidden layer: There is no fixed algorithm for
calculating the number of neurons in the hidden layer of the model, and the
number is closely related to the number of input layer and output layer, which
needs to be determined by experience and multiple tests. The number of neurons
in the hidden layer is 4, so the number of neurons in the hidden layer is 4.
Output layer setting: The output result of the shopping evaluation model
in this paper has only one comprehensive score about the product, so the output
layer setting has only one neuron.
BP
The solution of neural network evaluation model
Step 1: The connection weights between neurons
in each layer of network initialization
,
each weight
value is assigned an interval random number in (-1, 1), given calculation
accuracy and maximum learning times M, give hidden layer threshold and output layer thresholds
.
Step 2:
Input sample X = X1 ...Xn and the corresponding
expected output 
Step
3: Hidden layer output
calculation. According to the input vector X, connection weight between input
layer and hidden layer
, and hidden layerthreshold a ,calculate hidden layer output.


Step 5: Error calculation. According to the actual
output O and expected output D of the network, the overall error E of the
network is calculated.

Step 6: Weight update. According to the overall
network error E, update the network connection weight according to the
following formula

Step 7:
Training and convergence. When the average error of the calculated training
sample is less than ?, the whole training is over, otherwise, the above process
is repeated, and the weight and threshold are constantly modified. After
repeated calculation, the actual output of the network gradually approaches to
the corresponding desired output, which is also the process of the global error
of the network tending to the minimum. After repeated iterations, when the
error is less than the allowable value, the training process of the network
ends.
Conclusion
of question 1
The principal component
analysis is carried out to determine whether Amazon members have been
certified, whether purchasing power products and voting numbers have been
confirmed to be useful, and the evaluation index of credibility is obtained;
the evaluation grade is taken as the second evaluation index, and the text
length, the number of commodity characteristic words and the number of negative
emotional words are mined with Spyder data, and the corresponding values are
obtained after descriptive statistical analysis. And get the third evaluation
index of the comment title. Then the evaluation model of three product
evaluation indexes is established by using BP neural network.
The
model of problem 2
In order to get the
data measure that can best be tracked by the sunshine company from rating and
comment, we choose star rating, helpful votes, total votes, and evaluation
score as variables to establish four evaluation indexes. We use the fuzzy
evaluation theory to discuss these indexes, and finally give their
comprehensive impact to determine their final data measure, the specific flow
chart of the fuzzy evaluation theoretical model is shown (Figure 5).

Figure 5:
Process of fuzzy evaluation model.

According to this problem, we use a more
suitable weighted average model, that is, solution 4.
Define the weight
coefficient. It can be seen from the reality that the comprehensive evaluation
will be positively
correlated with the three indicators of star rating, helpful votes and
evaluation score, and the user will choose to watch helpful votes and comments.
Total votes includes helpful votes and some voting data with negative
correlation. Therefore, the definition
.
Comprehensive
evaluation: 
Solution: first
normalize the sample data, then normalize the whole data, and then substitute
the obtained value into the formula to get the comprehensive data value
.
Solution
of model
Make correlation
analysis between the comprehensive index data of sample data
and the evaluation degree
of sample data, and the results are shown (Table 7).
Conclusion:
the analysis shows that the correlation between the two models is basically the
same, which confirms the accuracy of the neural network model of question one
and this model. Through this model, we can accurately
provide data
measurement based on rating and comment for sunshine company, and sunshine
company can analyse the market of goods according to these measurement.
The
model of problem b
Model establishment and solution: This model adds time measurement mode, and establishes time
rating model by using the evaluation reliability index discussed in question 1.
Because the recognition and discussion of three product data sets based on time
measurement and pattern are similar, only the blower is discussed in detail,
but the data recognition process is similar, so the time rating model of the
blower is analysed carefully, which is rough in the analysis of microwave oven
and pacifier, but also gives the analysis results in detail and clearly.
Establish time rating model for hair dryer: According to the evaluation grade,
evaluation title and evaluation equation of question 1:
Evaluation Level:

Through the time series
analysis and prediction of SPSS, we can respectively get the observation chart
of the star change trend of the blower based on the time measurement as shown
in figure 6, and the observation chart of the comprehensive change trend based
on the evaluation score and star level under the time measurement as shown in
figure 7, as well as their influence chart, namely the overall change trend
chart, as shown (Figure 6,7).
According to the consumer's star level change
and the overall change trend chart, we can know that the star level is on the
rise. From 2013 to 2014, the rating rose rapidly, but it was also in a rapid
decline stage in the same year, but the overall trend was still on the rise. In
other words, the higher the star rating of consumers is, the higher the value
is, the greater the reputation of products will be, and the greater the impact
of consumers' purchase decisions will be. In order to improve the analysis and
the reliability of the analysis results, in view of this problem, the
evaluation star level evaluation score is also considered comprehensively.
After the correlation analysis, it is considered that the evaluation star level
and the evaluation score are related to a certain extent, so under the time.

Figure 6: Star change trend
based on time measurement.

Figure 7: Overall trend of star
change.

Figure 8: Trend of total evaluation
scores based on time measurement.

Figure 9: Overall trend of total
change.
Measurement, the change
trend is observed, and then the star level change under the time measurement is
analyzed separately. Trends are compared for reliability of results. After the
software analysis, we can get the change trend and the overall trend as shown
(Figure 8,9).
According to the
evaluation score of the hair dryer by consumers and the comprehensive trend
chart of star level changes, it can be seen that the comprehensive change shows
a downward trend at the end of 2015, but on the whole, it is still an upward
trend. It can be seen from the figure that the evaluation of hairdryer by
consumers reached the peak of evaluation score and star rating in 2015, and
then declined. This trend is similar to the change trend of star rating and
evaluation score from 2011 to 2012, so it is not ruled out that the problem of
product quality and consumers' evaluation psychology of purchasing goods. In
short, when analysing the comprehensive evaluation trend of evaluation score
and star rating, and analysing the comprehensive indicators of star rating and
evaluation score, it can be concluded that the reputation of products will
decline briefly after 2016, and then increase rapidly, but its reputation is
increasing in the online market in 2015 (Figure 10).

Figure 10: Forecast chart of
online market increase and decrease of hair dryer reputation.
Because the time series
analysis method of evaluation and rating of microwave oven, pacifier and blower
is similar, there is no detailed explanation when analysing microwave oven and
pacifier.
Establish
time rating model for microwave oven
Known by question 1:

The time-based measurement and pattern are
identified in the data set of microwave ovens. Because the comprehensive index
of star rating and evaluation score can better reflect the increase and
decrease of product reputation in the online market when the data set of hair
dryer is analysed and discussed, the comprehensive index of star rating and
evaluation score is directly considered in the analysis of microwave ovens, and
the star to product is not considered separately Influence. According to the
data set of microwave oven, after pre-processing the missing value and time
series, we can get the comprehensive trend chart of evaluation score and star
level based on the measurement of time series as shown (Figure 11).

Figure 11: Evaluation synthesis
trend based on time series measurement.
According to the comprehensive
trend chart of microwave oven evaluation score and star rating based on time
series measurement, the reputation of microwave oven is slowly decreasing in
the online market at this stage.
Time
rating model for pacifier
Known by question 1:

According to the data
set of the pacifier, after pre-processing the missing value and time series, we
can get the comprehensive trend chart of evaluation score and star level based
on the measurement of time series as shown (Figure 12).

Figure 12: Comprehensive trend
chart of pacifier score and star rating based on time measurement.
According to the
comprehensive trend chart of evaluation score and star rating of nipple based
on time series measurement, the reputation of nipple is slowly increasing in
the online market at this stage.
Conclusion
of question b
Based on the above
analysis, it can be concluded that the reputation of hair dryer is increasing
in the online market, the reputation of microwave oven is slowly decreasing,
and the reputation of pacifier is slowly increasing.
The
model of problem c
Analysis of model: In
order to better analysis of the product in a potential success and potential
failure, we choose the most can reflect real product quality indicators star
rating, evaluation score, number of comments, the five-star rating proportion.
See each item as a high- dimensional space of points, each evaluation index
represents the dimension on this point, using the comprehensive evaluation
method of fuzzy theory, the commodity properties of fuzzy similarity to high
point, construct the fuzzy clustering model.
Establishment
of model
Data Selection: In
order to avoid the volatility of evaluation indexes caused by too few data and
ensure that the number of comments on each model is more than 20, we randomly
select 20 products from three categories as samples and take the average value
of sample indexes for analysis. A total of 20 commodities are input into a
Two-dimensional matrix
with respect to three variables, which is called the observation matrix:

Solution
of model
Because the scalar
quantity we selected is positively related to the sales volume of the product,
we select the largest data [5400,1] in the sample data as the success point s W
, and calculate the result through the fuzzy clustering model as shown in the
figure below (Figure 13).