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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Neuron Network Model in the Study of Smart City Ideas</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Mátyás Varga</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Bence Soltész</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Norbert Béla Fiedler</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Anikó Apró</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Balázs Borsos</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Gábor Kiss</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Zoltán A. Godó</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Department of Information Technology, Faculty of Informatics, University of Debrecen</institution>
          ,
          <country country="HU">Hungary</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Institute of Machine Design and Safety Engineering, University of Óbuda</institution>
          ,
          <addr-line>Budapest</addr-line>
          ,
          <country country="HU">Hungary</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>Proceedings of the 1</institution>
        </aff>
      </contrib-group>
      <fpage>270</fpage>
      <lpage>278</lpage>
      <abstract>
        <p>With neural networks, computer science has made tremendous progress in the field of artificial intelligence. The breakthrough is provided by the closest possible analogy with the living nervous system, as it provides the most eficient processing of real-world data. In our work, we are looking for an even closer analogy with the living nervous system by building a neural network. We build the network hardware and emulate the nodes with multiprocessors. We implement actual concurrency, real-time task runs. We enable communication with both analog and digital features, thus mimicking the operation of natural systems. A unique interpreter at the nodes of the neural network provides controllable stream signal processing. Thus, the system is able to receive and process any data stream. By implementing cascade programming, the interpreter can also be developed. That is, the entire control language can be replaced according to the desired task. The system is not only suitable for Smart City or trafic modeling, but also for direct neuroinformatics or didactic research.</p>
      </abstract>
      <kwd-group>
        <kwd>Smart City</kwd>
        <kwd>neuron-network</kwd>
        <kwd>massively parallel system</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Problem Statement</title>
      <p>
        In today’s most popular personal computers, which are based on the von Neumann
architecture, true parallelism is not yet implemented [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ]. Despite modern
processors having multiple cores, the concept of per-core task execution points beyond
the complexity of current personal computer architectures. The basic advantage of
multicore processors is that they are capable of running multiple threads in
parallel at the same time. With multiple cores built into a single processor, the overall
performance is multiplied, thanks to calculations running parallel to each other.
However, processors that are capable of processing parallel instructions are called
superscalar processors.
      </p>
      <p>Typically, the real world can be characterized by data trafic that consists of
unprocessably many, parallel signals. This is further complicated by the fact that
everything around us is analog. However, traditional computer processing works
with quantized numbers, which are digitized with a high degree of loss, and move
in a discrete range of values.</p>
      <p>
        The world around us, physical and chemical phenomena, or the usage of a
manmade environment such as a Smart City, can be most efectively interpreted by
the central nervous system of living beings [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. While computers are more suitable
for data processing, the data will be used by an individual with a nervous system.
Vital processes, orientation, usage of the environment, social interactions etc. are
all handled by the brain as a supercomputer in the most efective way.
      </p>
      <p>
        However, the nervous system is typically an analog, massively parallel neuron
system [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]. To be exact, the living nervous system is not the one that is similar to
the artificial model, but it is the artificial model that was used to try and copy the
natural structure of the brain. It is quite clear, that if the central nervous system
is such an eficient user system, similar artificial structures have to be built if we
want to approximate the eficiency of the natural system. While neural networks
are software emulated parallel systems on a von Neumann architecture machine,
the goal of neuron networks is to achieve true, full, hardware architecture based
parallel task execution. Neural networks already provide some amazing results,
for example with learning algorithms or diferent levels of artificial intelligence.
Therefore, we can expect even more exciting results from neuron networks, which
are much closer to the structure of the natural nervous system.
      </p>
    </sec>
    <sec id="sec-2">
      <title>2. Levels of Parallelism</title>
      <p>Multiple levels of parallelism can be implemented. On the highest level, we have
parallelism between processes. Then comes parallelism between jobs, parallelism
between procedures (macro instructions), parallelism between instructions,
parallelism on the level of processed data, parallelism within the execution of an
instruction, and on the lowest level, parallelism within a hardware unit. Our goal was
to implement parallelism on the lowest level, which has the closest analogy to the
‘evolution-developed’ central nervous system.</p>
      <p>
        Several scientific and engineering problems can be better approached in a
parallel neuron network model. With the system that we developed, we would like
to model [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ] Smart City dataflow, the propagation of information and the city
trafic as well [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. Due to its universal structure, any other field can be modelled
with it, with the change of the processor’s program. For example, an obvious
use case would be neuro-informational application, due to the similarities with the
nervous system [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ]. In this case we would connect the system with a living
nervous system and implement two-way communication. In the past, we have already
achieved connection with a living nervous system, using only 9 processors and 256
microelectrodes.
      </p>
      <p>In our current research, 216 high performance processors are available, which
makes it possible to build a 6 x 6 x 6 sized, massively parallel neuron system cube.</p>
      <p>Taking use of modern technological opportunities, nodes are represented by
complete microcontrollers. This way, each node in the neuron network contains a
combined processor, memory, and I/O unit. This means that it does not simply
work as a Kirchhof node, like in the CNN model, but as a complete,
programcontrolled, data and program processing unit.</p>
      <p>Gustav Kirchhof’s Current Law is one of the fundamental laws used for circuit
analysis. This law states that for a parallel path the total current entering a circuits
junction is exactly equal to the total current leaving the same junction.</p>
      <p>
        The name of CNN stands for Convolutional Neural Network. The model is the
most popular among the other deep neural networks (for example: Deep Neural
Network(DNN) or Artificial Neural Network(ANN)). The model takes its name
from a mathematical linear operation between matrixes called convolution. This
type of model has multiple layers just like our microcontroller system. The model
itself has a great performance in machine learning problems. We will use this
performance to analyze a city’s trafic and more [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ].
      </p>
      <p>Shared nothing systems are concerned with access to disks, not access to
memory. Nonetheless, adding more CPUs and disks can improve scaleup.</p>
    </sec>
    <sec id="sec-3">
      <title>3. Massively Parallel Systems</title>
      <p>Massively Parallel (MP) systems have the following characteristics:</p>
      <p>We do not need thousands of nodes to build a working parallel system from
only few nodes we can set up a whole system which contain the characteristic of
these kind of systems. Even if we can aford an MP system we do not need to
spend a lot of money because the cost of the nodes can be extremely low.</p>
      <p>Each node has a non-shared memory so the memory capability of the system is
grow with the amount of nodes equally. Every microcontroller is a unique device
so they do diferent tasks, but even if a controller is wrong the other nodes can
access to the failed device and take it’s task or compute with the controller’s data.</p>
      <p>There is multiple organization type of the nodes. We can build a grid topology
where the controllers close a square shape on the same level (for example a table)
or a mesh organization type where nodes will form a hexagon shape. If we do
not want the processors to be on the same level we can build a cube form where
every node will form a three dimensional cube formation which is called hypercube
arrangement.</p>
      <p>The software can potentially reside on all nodes but in a tokenized form so every
controller has a unique ID.</p>
      <p>
        A massively parallel system may have as many as several thousand nodes [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ].
Each node may have its own software instance, with all the standard facilities of
an instance.
      </p>
      <p>An MP has access to a huge amount of real memory for all database operations
(such as sorts or the bufer cache), since each node has its own associated memory.
To avoid disk I/O, this advantage will be significant in long running queries and
sorts.</p>
      <p>
        Examples of massively parallel systems are the inCUBE2 Scalar Supercomputer,
the Unisys OPUS, Amdahl, Meiko [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ], and the IBM SP.
      </p>
      <p>
        The Unisys OPUS is a parallel computer system. This system was a low-cost
and high-speed machine that was gaining acceptance fastly in the corporate. This
computer was built to make processes and computations fast instead of scientist
[
        <xref ref-type="bibr" rid="ref12">12</xref>
        ]. We would like to earn the same result with our neural network.
      </p>
      <p>
        The Amdahl is a law that based on parallelism. The theory of doing
computational work in parallel has some fundamental laws that place limits on the benefits
one can derive from parallelizing a computation [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ]. This law helps us to speed up
the process time of diferent computations which would be great for our system.
      </p>
      <p>The IBM SP (SP stands for Scalable POWERparallel) is a series of
supercomputers from IBM. The SP was introduced back in 1993. This computer is a
distributed memory system, consisting of multiple RS/6000-based nodes
interconnected by an IBM-proprietary switch called the High Performance Switch (it is also
called HPS).</p>
      <p>Figure 1 of ours is representing a shared memory and CPU system where one
Processing node can give its computations through a network to another node.
Because of this ‘sharing system’, one node can only work with one process and
another controller with another computation. As a result the problem solving time
will be reduced dramatically because if we give one complex problem to one node,
then it has to be solve every part of the problem. So this is the layer structure we
talked about before in the CNN model. We ‘break’ the problem into pieces and
then because all node is connected (just like in the picture) to each other, one node
has only one job to be done.</p>
    </sec>
    <sec id="sec-4">
      <title>4. Analog Implementation</title>
      <p>
        Our system under construction is capable of performing tasks of any complexity
due to intelligent nodes [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ]. The program uploaded to the nodes is suitable for
controlling the data flow, which is realized by the connections of the I/O PINs of
the node microcontrollers. Because the nodes are separate processing units, it is
possible to implement analog data trafic in addition to, or instead of digital.
      </p>
      <p>Analog stream processing adds new possibilities to the system. Because signals
from the natural environment are typically analog, the architecture of our neural
network system is also closer to the nature of the data to be processed (see Figure 2).</p>
      <p>
        If we analyze Smart City problems, a number of analog signals need to be
processed [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ]. Analog communication is typically represented by voltage levels
in similar systems. A refined model of this is when a so-called fill factor (PWD)
provides the voltage signal level. This way, the analog signal can be produced with
the frequency of the digital signal. This solution is also interesting because in the
living nervous system, the flow of information between living neurons takes place
on a similar principle. The signal is binary, where 1 is the value of the action
potential and 0 is the value of the resting potential. In addition, due to the ‘all or
nothing’ law, neurons cannot take on an intermediate value. So they are discrete or
stable at 1 or 0. If that were all the ‘science of neurons’ we could already connect to
our digital computers. However, the information in the nervous system is carried
by frequency, i.e., the time course of states 0 and 1.
      </p>
      <p>
        The Artificial Neural Network (ANN) is a computing system inspired by
biological neural network [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] that constitute animal brain but it can be easily implemented
in other areas such as Smart City. The system contains one input layer (picture
layer 1) where the data which has to be processed flows in then there are multiple
hidden layers (picture layer 2 and 3) where the actual computations will be done.
The last layer is the output layer (picture layer 4) where the processed result is
given by the computation. In our model it is representing the position and tasks
of the micro controllers. The input layer will be our main controller (see Figure
3) and the hidden layers will be the other nodes. And in our implementation the
result (the output layer) will be a picture or some information on our computer.
      </p>
    </sec>
    <sec id="sec-5">
      <title>5. Software Levels</title>
      <p>
        Node microcontrollers require multi-level program execution [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]. The most basic
program is the bootloader, which is responsible for uploading and executing the
running main program. We can upload our own main program to the nodes
running below this. However, the running main program is an interpreter that will
process the data stream. The stream contains special control information that
gives instructions on how to process the stream. This allows for extremely complex
processing and wide applicability [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ].
      </p>
      <p>As a first step, the bootloader must be rewritten before the 216 fixed circuit
processors are installed. This is because replacing the main program cannot be solved
by programming the processors one by one. Instead, we need to use something
called cascade programming (See Figure 3). The point is that the first processor
receives the new master program, and then the modified bootloader passes the
master program to the next program via an I/O PIN. This way, programming takes
place automatically in a cascaded system. Each node has its own ID. This allows
the main program to adapt to the physical location of the node. As a result, the
interpreter program processing the data stream can be developed at any time after
the neuron network has been assembled. The scripting language that controls the
interpreter can also be developed and expanded.</p>
      <p>
        The main program then becomes capable of receiving and sending data streams
to neighboring nodes via dedicated I/O PINs [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. The instructions placed in the
data stream are interpreted and executed by the main program as an interpreter.
Follow the instructions to switch to analog or digital data transmission. Trafic can
be controlled by telling which node or nodes we want to forward the data stream
to [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ]. It can be transformed, processed and also multiplied or reduced. All this
can be controlled by instructions placed in the datastream. So the universality of
the system is very extensive.
      </p>
    </sec>
    <sec id="sec-6">
      <title>6. Summary</title>
      <p>
        A stream-driven, massively parallel neuron network with such a structure, with
both analog and digital features, with such a large number of intelligent
processors, running an intelligent interpreter [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. It is completed with serious and very
thoughtful planning. Therefore, its presentation and expected results may be of
great interest to the scientific world. It is universal analog-to-digital architecture
and data stream interpreter control open up exciting modeling opportunities in
Smart City modeling [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ].
      </p>
    </sec>
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