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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>CITI'</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>Machine Learning Methods and Taking Into Account Climatic Indicators</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Grigorii Shymchuk</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Iaroslav Lytvynenko</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Roman Hromyak</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Sergii Lytvynenko</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Volodymyr Hotovych</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Ternopil Ivan Puluj National Technical University</institution>
          ,
          <addr-line>56, Ruska Street, Ternopil, 46001</addr-line>
          ,
          <country country="UA">Ukraine</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2023</year>
      </pub-date>
      <volume>1</volume>
      <fpage>14</fpage>
      <lpage>16</lpage>
      <abstract>
        <p>This paper examines a method for forecasting gas consumption based on the application of an additive mathematical model. One of the components of the mathematical model is a cyclic random process. The forecast is constructed using machine learning methods, specifically gradient boosting and decision trees. When constructing the forecast, climatic factors that influence natural gas consumption were taken into account. It has been established that the developed forecasting method, which considers the cyclic component of gas consumption in the model, exhibits higher accuracy compared to the known method.</p>
      </abstract>
      <kwd-group>
        <kwd>Cyclic process</kwd>
        <kwd>gas consumption process</kwd>
        <kwd>statistical processing</kwd>
        <kwd>cyclic random process</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>The increasing demand for energy consumption in various industries creates the prerequisites for
the development of numerous means and methods of optimization and control over the use of these
resources. Natural gas consumption is no exception. The availability of a significant amount of data on
gas consumption allows for the efficient application of machine learning and decision-making methods
to improve gas consumption processing and forecasting tasks. Moreover, decision-making methods are
also used to assist operators in making informed decisions regarding the optimization of gas
consumption processes. These methods prove their effectiveness in monitoring gas consumption
processes, reducing electricity costs, and minimizing environmental impact. In this context, the subject
of processing and forecasting natural gas consumption attracts significant interest from researchers and
practitioners</p>
      <p>who are interested in developing innovative solutions to improve results. New
mathematical models and gas consumption processing and forecasting methods using machine learning
techniques are of particular interest.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Analysis of recent research</title>
      <p>Many researchers are engaged in the development of gas consumption forecasting methods. For
instance, in [1], three different types of models for short-term natural gas consumption forecasting on a
daily basis were developed. The authors used a sigmoid regression model, a feedforward neural network
model, and a recurrent neural network model. The results obtained indicate that the accuracy of the
forecast based on artificial neural networks was higher than the accuracy of the forecast based on the
sigmoid regression model.</p>
      <p>In [2], mathematical models for gas consumption forecasting were proposed, including models based
on logistic curves, statistical models, econometric models, neural networks, and genetic algorithms.</p>
      <p>2023 Copyright for this paper by its authors.
Machine learning methods such as artificial neural networks (ANN) and support vector regression
(SVR) were used to forecast natural gas consumption based on secondary data collected under various
influencing factors.</p>
      <p>In [3], gas consumption forecasting was proposed using hybrid neural networks with the approach
of artificial bee colonies.</p>
      <p>The study presented in [4] provided gas consumption forecasting results obtained using artificial
neural networks (ANN). Specifically, the MLP model (multilayer perceptron model) was used, and the
training was performed using data describing actual gas consumption.</p>
      <p>In [5], four different forecasting models using a block structure and combining its elements to create
three hybrid models were developed. Overall, the application of models based on artificial neural
networks showed higher accuracy compared to gradient boosting models, and the combined (hybrid)
models demonstrated significantly better results in forecasting.</p>
      <p>The research conducted in [6] aimed to develop efficient neural network models for predicting
natural gas energy demand by utilizing various quantitative and qualitative input data, including social
factors. The neural network model had a deep, complex architecture with multiple layers and nodes.
Three different approaches were tested, including artificial neural networks (ANN), long short-term
memory (LSTM) models, and a proposed implementation of deep neural networks (DNN). The
proposed DNN implementation outperformed the ANN and LSTM approaches.</p>
      <p>In [7], short-term forecasting for the next day was investigated. The authors proposed a model that
employed wavelet transformation, genetic algorithms, and neural network methods for demand
forecasting.</p>
      <p>In [8], neural networks and a sliding window approach were used for forecasting gas consumption
for the next day, and it was found that although the algorithm training was demanding, the applied
algorithm was relatively simple and did not require extensive computational resources.</p>
      <p>The article in [9] focused on the importance of gas consumption forecasting in the residential sector,
comparing four different models, two neural network models, and two econometric models to find the
most accurate method for forecasting monthly natural gas demand. The selected forecasting period
spanned 24 months, and the comparison aimed to assess the strength of different models in each specific
problem.</p>
      <p>In [10], the use of deep neural networks for short-term gas consumption forecasting was proposed,
comparing them with a linear regression model and a traditional artificial neural network model.</p>
    </sec>
    <sec id="sec-3">
      <title>3. Main part</title>
      <p>
        In [11], an additive mathematical model of the gas consumption process was proposed, one of the
components of which was a cyclic random process. Let us briefly consider this model. The model of
the cyclic random process of gas consumption  ( ,t) is presented in the form of an additive model (
        <xref ref-type="bibr" rid="ref1">1</xref>
        )
consisting of three components:
 (,t) =  (,t) + ftr (t) + frem(,t), t  W,  Ω, Ω ,
(
        <xref ref-type="bibr" rid="ref1">1</xref>
        )
where  (,t) – cyclic component, ftr (t) - trend function, frem( ,t) - stochastic function remainder.
      </p>
      <p>
        In practice, we have to deal with discrete data, so it is convenient to work with the mathematical
model (
        <xref ref-type="bibr" rid="ref1">1</xref>
        ) in this form:
      </p>
      <p>
         (l) = (l) + ftr (l) + frem  (l), l  W = D , (
        <xref ref-type="bibr" rid="ref2">2</xref>
        )
where  (l) – implementation of the cyclical component of the gas consumption process, ftr (l) - trend
function, frem  (l) - function stochastic remainder, l - discrete readout of the gas consumption process.
      </p>
      <p>
        Also, work [11] shows how each of the components of the additive mathematical model is obtained,
so we will consider  (l) - cyclic component of the mathematical model (
        <xref ref-type="bibr" rid="ref2">2</xref>
        ), which carries information
about the gas consumption process, we will present it in the form of:
      </p>
      <p>
        C
 (l) =  fi (l), l  W , (
        <xref ref-type="bibr" rid="ref3">3</xref>
        )
      </p>
      <p>
        i=1
where C – the number of segments-cycles of the cyclic process of gas consumption. W – region of
definition of the cyclic process of gas consumption, and the region of its values, for the case of the
stochastic approach, is the Hilbert space of random variables set on one probability space
( (l)Ψ = L2 (Ω, P)). In construction (
        <xref ref-type="bibr" rid="ref3">3</xref>
        ), there are segments-cycles fi (l ) of the cyclic process of gas
consumption are determined through indicator functions, i.e
      </p>
      <p>fi (l) = (l) IWi (l), i =1,C, l  W .</p>
      <p>At the same time, the indicator functions that distinguish segments-cycles were defined as:</p>
      <p>Wi = li, j , j = 1, J , i = 1, C .</p>
      <p>
        The segmental cyclic structure Dˆc is taken into account by a set of time counts {li} or li, j , i =1,C
j = 1, J , where J – the number of discrete counts per cycle. This form of the mathematical model (
        <xref ref-type="bibr" rid="ref6">6</xref>
        )
takes into account the rhythm of the cyclic process of gas consumption through a continuous function
of the rhythm T (l, n) , namely:
      </p>
      <p>
        IWi (l) = IWi+n (l + T(l, n)) , i = 1,C, n = 1, l  W . (
        <xref ref-type="bibr" rid="ref7">7</xref>
        )
To assess the rhythm function T (l, n) define the segmental structure of the gas consumption process
[12], as Dˆc = {li ,i =1,C} , after that, the rhythmic structure is evaluated and statistical processing methods
are applied in the further processing steps.
      </p>
      <p>In work [11] it is shown that for an adequate description of the real process of gas consumption, it
is necessary to take into account changes in the amplitude of the load on segments-cycles, which are
caused by various climatic factors such as: temperature, pressure, wind force and others.</p>
      <p>
        Let's denote these factors by a vector N = 1Wi (l), 2Wi (l),... N Wi (l), l  Wi , i = 1, C, and in model
(
        <xref ref-type="bibr" rid="ref4">4</xref>
        ) we take into account its multiplicative component, taking into account indicator functions and scale
coefficients of gas consumption amplitude, i.e., the component of mathematical model (
        <xref ref-type="bibr" rid="ref4">4</xref>
        ) will have the
form:
      </p>
      <p>
        fi (l) =  (l) Wi (l)  IWi (l), i = 1,C, l  W . (
        <xref ref-type="bibr" rid="ref8">8</xref>
        )
      </p>
      <p>
        In formula (
        <xref ref-type="bibr" rid="ref8">8</xref>
        ) of the component  Wi (l) , reflects the scale coefficients of the amplitude of gas
consumption on each segment-cycle of the cyclic process, namely:
(
        <xref ref-type="bibr" rid="ref4">4</xref>
        )
(
        <xref ref-type="bibr" rid="ref6">6</xref>
        )
(
        <xref ref-type="bibr" rid="ref9">9</xref>
        )
 i , l  W ,
 Wi (l ) =  0, l  Wii. , i =1,C ,
where  i – scale coefficients of gas consumption amplitude on each i -th segment-cycle are defined as
follows:
 i =  imax , i =1,C , (
        <xref ref-type="bibr" rid="ref10">10</xref>
        )
      </p>
      <p> aver
where  imax – the maximum value of the amplitude of gas consumption on i -th segment-cycle
(determined at the stage of segmentation of the cyclic process of gas consumption),  aver - the average
value of the amplitude of gas consumption (the maximum value of the amplitude of the estimate of
mathematical expectation, determined at the stage of statistical processing of the cyclic process of gas
consumption).</p>
      <p>For the climate indicator vector  N =  nWi (l), n = 1, N , l  Wi , i = 1, C a fair ratio that takes into
account the climatic parameters that affect gas consumption in each segment-cycle of the cyclic process,
namely:</p>
      <p>
        nWi (l) = 0ni,,llWWi .i, , i =1,C , n = 1, N , (
        <xref ref-type="bibr" rid="ref11">11</xref>
        )
where  ni climatic parameter (value) which corresponds n –th climatic indicator (temperature, pressure,
etc.) on each i - th segment-cycle of the gas consumption process.
      </p>
      <p>Let's consider the developed method of forecasting gas consumption taking into account climate
indicators using machine learning methods. Figure 1 shows the input data of gas consumption during
2006-2021.</p>
      <p>2007
2010
2013
2016
2019</p>
      <p> (l)
70000  (l)
60000
50000
40000
30000
20000
10000
0</p>
      <p>l, year
frem (l)</p>
      <p>l, year</p>
      <p>Examples of climatic indicators that affect the gas consumption process are shown in Figure 4, since
climatic indicators are recorded at different intervals, the figure shows only the maximum values of
climatic indicators that affect the gas consumption process.
3Wi (l), %
a) b)
Figure 5: Structural diagram of formation of gas consumption forecasting using different training data:
a) incoming data in the form of the gas consumption process; b) incoming data for training in the form
of the cyclic component of gas consumption</p>
      <p>We will apply two models and two sets of data to forecast gas consumption values and compare the
obtained forecast results taking into account climatic indicators. To this end, for the first approach, we
will take a neural network model of gradient boosting and a model based on decision trees for training,
l, year
N = nWi (l), n = 1, N,l  Wi ,i = 1,C
Formation of the  pred (l), l  W1
gas consumption
cycle forecast taking
into account the
selected model
N = nWi (l), n = 1, N,l  Wi ,i = 1,C
and input data in the form of the gas consumption process presented in Figure 1 (without processing).
At the same time, we will get the forecast results shown in Figure 6. When forecasting, the root mean
square error for the case of applying a forecast based on gradient boosting is 0.8915, and for the case
of a forecast based on decision trees is 0.937.
b)
Figure 6: Forecasted gas consumption values and gas consumption input data (learning from gas
consumption input data, Figure 1): a) prediction based on the application of the gradient boosting
model; b) prediction based on the application of the decision tree model</p>
      <p>For the second approach, we will use the neural network model of gradient boosting and the model
based on decision trees for training, and the input data in the form of the gas consumption process
presented in Figure 3 (processed cyclic component). At the same time, we will get the forecast results
shown in Figure 7. When forecasting, the root mean square error for the case of applying a forecast
based on gradient boosting is 0.904, and for the case of a forecast based on decision trees, it is 0.953.
b)
Figure 7: Forecasted gas consumption values and input gas consumption data (learning based on the
cyclic component of gas consumption, Figure 3): a) prediction based on the application of the gradient
boosting model; b) prediction based on the application of the decision tree model</p>
      <p>Let's proceed to the discussion of the obtained results.</p>
    </sec>
    <sec id="sec-4">
      <title>4. Discussion of obtained results</title>
      <p>From the results obtained, it follows that the root mean square error for the case of applying the
gradient boosting model is larger than in the case of applying the model based on decision trees. In
addition, training the network based on the input data in the form of a cyclic component of the gas
consumption process and forecasting on its basis showed that the root mean square error is significantly
lower than the others, which indicates the accuracy of forecasting and makes the developed forecasting
method better than others.</p>
    </sec>
    <sec id="sec-5">
      <title>5. Conclusions</title>
      <p>In this paper, a gas consumption forecasting method was developed based on the application of
gradient boosting machine learning methods and a method based on decision trees. From the obtained
results, it was found that the forecasting method based on the model of decision-making trees more
accurately forms the forecast of gas consumption values. In addition, we found that the forecast based
on the learning of the input data in the form of a cyclic component of gas load gives better results
compared to the forecast based on the input data of gas consumption presented in Figure 1. Because the
developed method allows for a more accurate forecast in contrast to the use of other models.</p>
      <p>It is planned to conduct a study on the formation of a forecast based on the application of a model
in the form of a random forest and to compare the obtained results with the developed forecast method.
It is planned to develop an appropriate software complex for predicting gas consumption too.</p>
    </sec>
    <sec id="sec-6">
      <title>6. References</title>
    </sec>
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