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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Neural Validation of Grammatical Correctness of Sentences</article-title>
      </title-group>
      <contrib-group>
        <aff id="aff0">
          <label>0</label>
          <institution>Dawid Połap Institute of Mathematics Silesian University of Technology Kaszubska 23</institution>
          ,
          <addr-line>44-100 Gliwice</addr-line>
          ,
          <country country="PL">Poland</country>
        </aff>
      </contrib-group>
      <fpage>25</fpage>
      <lpage>30</lpage>
      <abstract>
        <p>-In this paper, the idea of validating the correctness of sentences has been presented. In the proposed solution, traditional and modern theories of syntax grammar were used. In addition, preprocessing of sentences and neural approach to the problem has been shown. For different sentences the proposed method has been tested. Research results were presented and discussed in terms of the advantages and disadvantages of the presented method.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>I. INTRODUCTION</title>
      <p>Artificial intelligence (AI) is becoming a major direction of
today’s science. Scientists of various fields biology,
mathematics, physics and computer science try to improve and enrich
the daily lives with new technologies that are the cornerstone
to achieve true AI. Numerous application of methods known as
AI allow us to choose more and more bolder science majors.</p>
      <p>
        One of the main applications of these methods are image
processing and pattern recognition. For example, in [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ], [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ],
the authors proposed an alternative method of compressing
digital images; in [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] the idea of using methods inspired by
natural and physical phenomena to the problem of finding key
points was explained. This problem has numerous applications
in modern medicine, where key points on X-RAY images
may represent a variety of diseases. The creation of decision
support systems based on key points can help in diagnosis
of difficulties to detect diseases and even prevented them
by fast detection. In numerous scientific papers ([
        <xref ref-type="bibr" rid="ref4">4</xref>
        ], [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ]) a
possibility of using methods of computational intelligence to
acquire such knowledge was shown, which in the next stage of
research was used in decision support systems. For example,
in [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ] the use of knowledge of employees in the company to
create meaningful groups of human resources in the company
was discussed. Moreover, in the case of pattern recognition
common problem is the number of samples (knowledge)
required for the proper operation of the algorithm. Quite often,
the number of these samples is just too small. In order to
increase their numbers, many algorithms are developed for
this purpose. In [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] was shown that the theory of fuzzy sets is
a good option. Another solution is the use of computational
intelligence [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]. Of course, the method of knowledge transfer
for the various systems is also created, for instance for open
Copyright c 2016 held by the authors.
and closed teacher-learner systems [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. In [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ] the possibility
of using hardware design patterns in System-on-Chip designs
was discussed. The frequent developing large applications
require continuous supervision of changes and relationships.
An important issue is to improve the changes in the existing
code, for example, by finding and saving design patterns that
have already been made [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ].
      </p>
      <p>
        Heuristic algorithms are widely used in other practical
problems of modern computing as traffic optimization in digital
databases where particle swarm algorithm was used [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. In
[
        <xref ref-type="bibr" rid="ref12">12</xref>
        ], the authors presents an application of neural networks
to predict air pollution concentration for various chemical
factors. The idea presents a model of virtual monitoring station
points. Another increasing problem is the growing amount
of data, and with it - the problem of queuing and database
searches. Queuing is a problem that was born in the 50s of the
last century with the development of the telecommunication
networks. In the era of the Internet, the problem of queuing
has grown - servers, databases, service providers, shops and
websites are just a few examples where better and better
solutions are needed today. In [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ] the idea of the use of heuristic
methods to positioning of queuing models was shown, and in
[
        <xref ref-type="bibr" rid="ref14">14</xref>
        ], [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ] the applicability of sorting algorithms for databases
with a very large number of records. While [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ] presents an
algorithm to create mazes by artificial ant colony algorithm
that may be used in two-dimensional games. Again in [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ]
was shown that use of computational intelligence as a manager
in real-time cloud-based game management system where the
algorithm modifies the game depending on the randomness
and movement of the player can increase efficiency. As the
final result, the method of creating games that scenarios are
variables in real time was created so the game is different for
each approach.
      </p>
      <p>
        Natural language processing is another well developed area
of computer science. In [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ], the authors proposed the use of
natural language processing in an accurate and efficient
identification of problems related to opioid. Again in [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ] presented
a probabilistic framework that allows robots to perform your
commands without knowing the environment. The authors
tested and presented the results of their research on two mobile
robots. Analysis of the authorship identification methods in the
national language electronic discourse is presented in [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ]. In
the paper, an analysis of methods for English and discussed
generalization of these methods for different languages were
presented.
      </p>
      <p>
        Moreover, there is more and more need for chat-bots,
or question-answer systems or even systems that enable a
conversation with a machine. In [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ] was shown an innovative
approach to natural language processing by the neural network
composed of several parts - Sentence Layer, Layer Knowledge,
Deep Layer Case and Network Dictionary. This approach
allowed the authors to obtain first of all associative memory
and a question-answering system. Natural language processing
is quite complicated topic as evidenced by the numerous works
of different approaches to the subject. [
        <xref ref-type="bibr" rid="ref22">22</xref>
        ] presented the idea
of using image-text modeling, where the system was taught
words using their representation. Moreover, the authors claim
that their algorithm offers easy transfer to the sound. Many
scientists from the whole world try to modify existing methods
to get the best results eg.: convolution neural networks with
little hyper-parameter tuning with numerous modifications [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ]
and in [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ] shown the classic methods in this type of issue. An
interesting algorithm for learning neural probabilistic language
models was presented in [
        <xref ref-type="bibr" rid="ref25">25</xref>
        ]. The authors mentioned all
the disadvantages of learning using gradient methods and
large databases of words. They proposed algorithm based on
noise-contrastive estimation. After testing the algorithm, they
concluded that it is not only fast and effective but above all
stable algorithm.
      </p>
      <p>In this paper, two different approaches to automatic
recognition of grammatically correct sentences are shown.</p>
      <p>II. THEORIES OF SYNTAX AND GRAMMAR</p>
      <sec id="sec-1-1">
        <title>A. Traditional grammar</title>
        <p>There are two different ways of notation in the grammar.
The first one interprets the sentence as a combination of two
elements - subject and predicate. This is one of the most
common notation in English. To this day, it is called traditional
grammar which comes from the Latin and Greek grammars.
In this interpretation, we can identify some basic rules as
The sentence is composed of subject and predicate.
The predicate is regarded as a property or characteristic
of the subject.</p>
        <p>The predicate must contain a verb.</p>
        <p>Verb in the predicate requires a specific object,
predicative and adjuncts.</p>
        <p>The relation between the subject and the verb is called a
nexus.</p>
        <p>
          In [
          <xref ref-type="bibr" rid="ref26">26</xref>
          ], Otto Jespersen presented to the world the relation
nexus in context of the analysis written text. Nexus has been
described as a relation between the subject and his action in the
sentence. Introduced relation was intended to create a system
of symbols for parts of speech.
        </p>
        <p>Let me take the following sentence to illustrate the nexus
relation</p>
      </sec>
      <sec id="sec-1-2">
        <title>His father is a king.</title>
        <p>(1)</p>
        <p>In proposed sentence the father is the subject, is refers to the
action of the subjects and the king is the subject’s predicate.</p>
      </sec>
      <sec id="sec-1-3">
        <title>B. Modern grammar</title>
        <p>Modern grammar is strongly associated with the work of
the German mathematician Gottlob Frege. Frege was
interested in the theory of predicate in the field of mathematical
logic, which has become the cornerstone of new theories in
linguistics - Frege argued that there is a distinction between
sense and reference in relation to reference.</p>
        <p>
          In this context, predicates of a sentence are treated as a
mathematical functions. Predicates are used as a function that
can assign multiple arguments to each other, so each sentence
(in the linguistic sense) can be described mainly by predicates
and their arguments. In [
          <xref ref-type="bibr" rid="ref27">27</xref>
          ], the author used this mathematical
notation for linguistic sentences - applying this notation for
sentence in (1), we get
is(His father; a king) () is = f (His father; a king): (2)
According to this model, the verb is the predicate and the
noun phrase is an argument. In each sentence, all predicates
create a matrix predicates, which comprises verbs, adjectives
etc. Each sentence can be represented as a tree, where the
words are vertices, as shown in Fig. 1, 2 and 3.
        </p>
        <p>To train the neural networks, an important step is proper
preparation of samples. Neural network on the input accepts
vector of numerical values, and the sentence in the sense of
linguistics is not filed in numbers. To do this, we need to
re-evaluate the words into numerical values. Moreover, the
number of elements in samples is also important. The more
the value, the longer the time of learning.</p>
        <p>In order to reevaluate words in the numerical values used
both grammatical notations - traditional (II-A) and modern
(II-B).</p>
      </sec>
      <sec id="sec-1-4">
        <title>A. Traditional notation</title>
        <p>
          Algorithms type of part-of-speech tagging are related to
finding specific parts of speech in a sentence. In the 60s of
last century, the Brown Corpus (Brown University Standard
Corpus of Present-Day American English) interested in this
problem, created a huge database of words. It was not until
30 years later, in [
          <xref ref-type="bibr" rid="ref28">28</xref>
          ] used the hidden Markov models in this
issue. The simplest method is to find probability of occurrence
of a particular part of speech after the word. For example, if
the current expression is the, the next most likely is a noun
or an adjective. In subsequent years, in order to obtain higher
accuracy, the number of analyzed words was increased - to
three or four. Another known method of finding specific parts
of speech is algorithm called VOLSUNGA presented in [
          <xref ref-type="bibr" rid="ref29">29</xref>
          ].
        </p>
        <p>VOLSUNGA algorithm operates on the principle of finding
the optimal path based on the matrix of probabilities. For each
pair of words, the value p is calculated as the likelihood of
the analyzed pair of parts of speech, what can be described
by the following formula
p(p
pw) p(pw; pa);
(3)
where w is the word, and pw means the part of speech and
pa is a part of speech which may be the next word.</p>
        <p>For all paths, algorithm selects the most optimal solution.
In each iteration, a new word is added and the next optimal
solution is searched. At the end of the algorithm, the most
optimal path is returned, which represents the most likely
sequence of parts of speech for the analyzed sentence.</p>
        <p>In the case of traditional grammar, sentence must be
distributed on the subject and predicate. Using the VOLSUNGA
algorithm, we find a place of occurrence of the subject a
and verb b. In next step, values a and b are re-calculated in
accordance with
8&gt; v a
&gt;&gt;&gt;val1 = utu a1 X i2
&gt;
&gt;
&lt;</p>
        <p>i=0
&gt; v n
&gt;&gt;&gt;val2 = utu 1b X i2
&gt;
:&gt; i=b
;
where n is the number of all words in a sentence, and val1,
val2 mean the average amount of information contained in
the subject and predicate. Using these values and the value c
which takes the value 0 if sentence is incorrect or 1 in other
case, a six-element vector can be created as
[val1; val2; a; b; n; c] :
(4)
(5)</p>
        <p>Algorithm 1 VOLSUNGA algorithm
1: Start
2: Set probability matrix
3: for each pair of words do
4: Calculate the likelihood of analyzed pair using (3)
5: Select the most optimal solution
6: end for
7: Return the best solution
8: Stop</p>
      </sec>
      <sec id="sec-1-5">
        <title>B. Modern grammar</title>
        <p>For the grammar described in II-B approach, creating a
sample is much easier than for a traditional approach - the
problem is to find the matrix predicate. In the matrix predicate
will be a verb and specify verb for each tense eg.: for the
present perfect, it will be have/has. To find the matrix, we can
find each verb by VOLSUNGA algorithm or find specific verb
in the analyzed sentence and select the next verb.</p>
        <p>After finding the matrix, vector representing the sentence
can be created as
[val3; val4; val5; val6; k; c] ;
(6)
where k means the number of arguments, and the remaining
values are calculated by
8
&gt;
&gt;&gt;&gt;val3 =
&gt;&gt;&gt;&gt;&gt;&gt;&gt; vj=0
&gt;&lt;val4 = utu 1b Xcm i2
&gt;
&gt;</p>
        <p>v cj
Xk uu 1 X i2
t c</p>
        <p>i=0
i=0
;
(7)
&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;val5 = ck1mXj=k0 cj
&gt;:val6 =</p>
        <p>k
where cj is the number of words in j-th argument, cm
is the number of words in the matrix. Values val3, val4
represent average amount of information in arguments/matrix
and val5, val6 are arithmetic amount of words respectively in
the argument and the matrix.</p>
      </sec>
      <sec id="sec-1-6">
        <title>C. Example</title>
      </sec>
    </sec>
    <sec id="sec-2">
      <title>Consider the following sentence</title>
      <sec id="sec-2-1">
        <title>Whatever she made was always beautiful.</title>
        <p>(8)</p>
        <p>In the case of traditional notation, we obtain the following
values</p>
        <p>3
which comprise the following vector</p>
        <p>In the case of modern notation, we obtain
val3 =
val4 =
r 1</p>
        <p>2
r 1
5</p>
        <p>
          In order to validate the correctness of sentences, a neural
network was used ([
          <xref ref-type="bibr" rid="ref30">30</xref>
          ]–[
          <xref ref-type="bibr" rid="ref32">32</xref>
          ]) with back propagation
algorithm. Neural networks are mathematical models inspired by
the operation of the neural network in the human brain. Model
of the entire network can be divided into three types of layers:
an input, hidden and output. Each layer consists many neurons
where each of them is connected to all the neurons in adjacent
layers. The connection between two neurons is marked by
weight. Weights are selected in a random way at the beginning
of the algorithm.
        </p>
        <p>Fig. 4: The model of the proposed system to validate
grammatical sentences.</p>
        <p>Each neuron is composed of the value (signal y) of each
neuron from the previous layer and weights w imposed on
the connection between each pair of neurons. In the neuron,
each signal is multiplied by the weight and all the values are
summed. The value of the sum of products is understood as a
neuron argument. The output value of the neuron is the value
of the activation function. The sigmoid function is one of the
most popular which value is in the range h0; 1i and the formula
is</p>
        <p>f (x) = 1 + 1e x ; (9)
where is a parameter and x is the neuron argument calculated
by
x =
n
X wiyi;
i=0
(10)
where n is the number of neurons in the previous layer. In the
input layer, learning vectors (samples) are entering signals.
In the hidden layer, neurons recalculate values obtained from
previous layers and the output layer returns the result of the
network.</p>
        <p>For the purposes of validation of sentences, proposed
network is constructed of 6 neurons in the input layer, 3 neurons
in each of the 3 hidden layers and 1 neuron in the output layer.</p>
      </sec>
      <sec id="sec-2-2">
        <title>A. The Backpropagation Algorithm</title>
        <p>
          The Backpropagation Algorithm ([
          <xref ref-type="bibr" rid="ref33">33</xref>
          ], [
          <xref ref-type="bibr" rid="ref34">34</xref>
          ]) is used to
modify weights in the neural network to get the most accurate
learning. The algorithm assumes the calculation of error of
each neuron starting at the output layer until the first hidden
layer. Using the calculated error, the weight of the connection
between the neurons is respectively modified by
w = w +
w;
where
        </p>
        <p>w is an error calculated by
8
&lt;
:
w = f (x)(1
w = f (x)(1
f (x)(p
f (x))</p>
        <p>f (x))
X</p>
        <p>wi i
signals
where p is expected output.
for the output layer
for the hidden layer
(11)
(12)
Algorithm 2 The Backpropagation Algorithm</p>
        <p>
          For the purpose of checking the correctness of the proposed
validation, a database of 200 sentences was created. Every
sentence was processed in two vectors one for each grammar.
The neural network was trained for = 0; 6. In the next
step, each vector was processed by a trained neural network
to check the quality of the validation. The obtained results are
shown in Tab. I. The graph showing the error reduction over
the number of epochs is in Fig. 5 [
          <xref ref-type="bibr" rid="ref18">18</xref>
          ].
        </p>
        <p>Fig. 5: Sample neural network learning process error.</p>
        <p>The proposed system allows us to check whether a sentence
is grammatically correct. This is an important aspect for the
development of a communication system between man and
machine. The proposed solution includes two grammatical
notations. The results show that the use of modern theories
of language based on the logic of predicates can be crucial in
further developing the field of natural language processing.</p>
        <p>In future research work, we plan to further develop the
topic of natural language (including analysis of words and
sentences).</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>ACKNOWLEDGMENT</title>
      <p>Author acknowledge contribution to this project of
Operational Programme: “Knowledge, Education, Development”
financed by the European Social Fund under grant application
POWR.03.03.00-00-P001/15.</p>
    </sec>
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