=Paper= {{Paper |id=Vol-2786/Paper36 |storemode=property |title=Soft Computing based Clustering Protocols in IoT for Precision and Smart Agriculture: A Survey |pdfUrl=https://ceur-ws.org/Vol-2786/Paper36.pdf |volume=Vol-2786 |authors=Vatan,Sandip Kumar Goyal |dblpUrl=https://dblp.org/rec/conf/isic2/VatanG21 }} ==Soft Computing based Clustering Protocols in IoT for Precision and Smart Agriculture: A Survey== https://ceur-ws.org/Vol-2786/Paper36.pdf
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Soft Computing based Clustering Protocols in IoT for
Precision and Smart Agriculture: A Survey
Vatan, Sandip Kumar Goyal
Department of Computer Science and Engineering, Maharishi Markandeshwar Deemed to be University, Mullana, Ambala,
Haryana, India

                       Abstract
                       Industrial developments in the Internet of Things (IoT) have lined the way for new fields for
                       the use of wireless sensor network (WSN) technologies. Agricultural monitoring is a case in
                       point where IoT can help improve production, quality and output yield. The use of WSN and
                       data mining techniques will significantly improve many of the agricultural activities. One such
                       activity is the management of the amount of water in planted fields. In addition, during recent
                       years, WSN has become a more evolving field in precision farming. The key problem in the
                       development of WSN is the use of energy and the improvement of the life of the nodes. This
                       paper provides a systematic analysis of the clustering protocols based on soft computing
                       approaches that are used in the agricultural domain to increase WSN‟s lifetime. Classification
                       is carried out according to different soft computing techniques: swarm intelligence, genetic
                       algorithm, fuzzy logic, neural networks. The survey will then present a comparative analysis
                       of soft computing techniques with a focus on their goals along with their merits and
                       drawbacks. This survey enables the researchers to choose the suitable soft computing
                       technique used by clustering protocols for WSN-based precision agriculture.

                       Keywords
                       Internet of Things, Sensor Network, Swarm Intelligence, Genetic Algorithm, Precision
                       Farming,             Neural          Network,            Soft            Computing

1. Introduction                                                           research in this area. Over the past decade, the
                                                                          conventional farming has been oriented
Everyday       objects     are    fitted     with                         towards the latest use of technology called
microprocessors and transmission devices in                               „Precision Agriculture‟. Precision farming
the Internet of Things      (IoT) era, which can                          essentially uses wireless sensors for data
work collectively to support us turn our                                  aggregation,      irrigation    control,    and
environment for the better. In agriculture it is a                        information transmission arrangements to
favourable field where IoT devices can                                    farmers [2]. Farmers' knowledge of well-
mitigate several problems and deliver                                     growing field will lead to creative and accurate
favourable solutions. Agriculture uses around                             farming. Innovative farming techniques can be
70 per cent of the water supplies available.                              utilized by using IoT devices and Wireless
There is a shortage of food and water, due to                             Sensor Networks (WSN) in farming. The
the growing population and declining rainfall                             authenticity is that agriculture is nowadays
[1]. Therefore                                                            smart, precision, information storage, multi-
in recent years there has been a proliferation of                         storage, and data based. PA allows for greater
                                                                          flexibility in crop growing and livestock
ISIC‟21: International Semantic Intelligence Conference,
February 25–27, 2021, New Delhi, India                                    rearing. The productivity can be improved by
Mail:vatansehrawat@gmail.com(vatan),
hodce@mmumullana.org (sandip kumar goyal)
                                                                          using crop monitoring technology, and costs
            2020 Copyright for this paper by its authors. Use permitted
            under Creative Commons License Attribution 4.0
                                                                          can be minimised as more effective treatments
            International (CC BY 4.0).
            CEUR Workshop Proceedings (CEUR-WS.org)
                                                                          can be applied to crops. IoT devices can be
                                                                          utilized in monitoring techniques comprising
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of nodes that communicate with the                       accumulated and grouped using aggregate
atmosphere using sensors to collect                      functions and then transmitted to the sink,
information in actual time and relay it to a             thereby saving energy [5]. Data collection can
command room for further handling [3].                   be seen as a basic mechanism to minimize
                                                         energy consumption and to conserve scarce
A WSN incorporates automatic sensing,
                                                         resources. A successful strategy for data
handling and wireless communication systems
                                                         accumulation would decrease the amount of
into small units called as sensor nodes. These
                                                         network traffic in WSN environments leading
self-governing sensor nodes deploy the
                                                         to substantial energy savings. We have
geographic areas randomly and closely, track
                                                         examined the clustering in the literature [6]
the ambient environment or detect events,
                                                         and are the most widely used techniques for
digitise the data collected, and route
                                                         data aggregation in WSN. Clustering the
information to the resource-rich electronics
                                                         sensor nodes is an important mechanism that
system, stated to as the base station (BS) for
                                                         enables data to be distributed in a hierarchical
additional handling and analysis [4]. However,
                                                         network by splitting the network into small
the nodes have constrained bandwidth, power,
                                                         groups. In order to allocate the management
and resource processing and limited lifespan.
                                                         tasks efficiently between the nodes, few of
The main task of the node is to sense the target
                                                         them are chosen as the head of each cluster,
phenomenon like heat, light, pressure, and
                                                         commonly referred to as the cluster heads (
then apply the data as a query response to the
                                                         CHs), and non-CH nodes called member nodes
BS or sink. For WSNs, relative to data
                                                         join their closest CH as presented in Figure 1.
transmission,     the    computing       energy
                                                         The member nodes transmit data to the
consumption is less.
                                                         appropriate CHs, then CHs send collected data
Therefore, Data produced from neighbouring               to the BS. Since there is an equal quantity of
sensors are often redundant and highly                   data produced by the sensor nodes, the
correlated in precision agriculture. Therefore,          clustering uses the similarity between the data
instead of transmitting the data individually to         and then, by combining it, decreases the
the sink each time, a large amount of                    network load, resulting in a further effective
redundant data is removed if data is first               energy utilization. Soft computing seeks to
                                                         find precise approximation, which provides a




                                       Figure 1: Cluster architecture
                                                                                               282

robust, computationally efficient and cost-           conditions in WSN. Thus, in this paper lately
effective solution that saves time in the             proposed soft computing techniques based
computation. Most of these methods are                clustering protocols is examined which are
essentially optimistic about influenced               used for precision agriculture.
biological processes and patterns of social
behaviour. With the quick growth of soft              The rest of the paper is designed as below.
computing techniques over the past period [6-         Section 2 presents the use of IOT in
7], clustering protocols based on particle            agriculture.    Section 3 discusses the
swarm optimization, ant colony optimization,          clustering characteristics in WSN. In
genetic algorithms, fuzzy logic, and neural           section 4, the soft computing techniques
networks have been proposed for WSN based             based clustering protocols are momentarily
precision agriculture. A concept of using soft        examined. Section 5 delivers a relative and
computing techniques in WSN is to deliver             systematic evaluation of the studied
adaptability and robustness in relation to            protocols. After All, Section 6 introduces
network breakdown, and changing wireless              the conclusion and future research trends.




                                     Figure 2: IoT in Agriculture
                                                                                               283


2. IoT in Agriculture The idea of IoT               entire market continuum with expanded
caught attention through MIT's Auto-ID              benefits that are advanced end computer,
centre and its related publications on              system, and service connectivity. IoT
market exploration. IoT is basically an             provides suitable results for multiple
aggregation of various devices that                 applications, like smart healthcare, smart
connect, sense and cooperate with their             cities, protection, industrial management
interior and exterior via the embedded              and agricultural traffic congestion. In the
technologies found in IoT.     IoT has              agricultural field a large quantity of effort
developed the megatrend for next-                   has        been         performed         on
invention technology that can affect the
IoT technology to build smart farming results       3. Clustering in WSN
[4]. By exploring various problems and
challenges in agriculture, IoT has brought a        The benefits of separating the networks into
huge change in the agricultural atmosphere.         clusters are a) it improves scalability b) it is
Currently, with the advent of technology, it        easy to manage b) it declines the quantity of
has been predicted that farmers and                 data to be transmitted by aggregating and
technicians can find the resolution to the          summing up the data, c) it reduces the number
problems faced by farmers such as water             of relay nodes d) load balancing between
deficiencies, cost control and production issues    clusters e) it improves energy efficiency and f)
by using them. State-of-the-art IoT techniques      it increases network longevity etc.[10].
observed all the problems and provided results
                                                    3.1 Clustering characteristics
to improve efficiency while reducing costs.
Attempts made on networks of sensors allow          Typically, we describe individually clustered
us to gather data from nodes and to transmit it     WSN as having three key attributes: cluster
to central servers. Data gathered the sensors       properties, CH properties, and procedure
provides       information      on      different   properties for clustering.
environmental       conditions     for     proper   Cluster properties
monitoring of the entire system [8].
Monitoring ecological conditions or crop            Cluster properties are separated according to
                                                    cluster requirements, such as cluster number,
production is not only an element in crop
assessment, but there are many other factors        cluster volume. Below is a short description of
influencing crop production, such as field          each:
managing, land and crop monitoring,                        The number of clusters: The quantity
unwanted object progress, wildlife attacks, and             of clusters that were created may
theft etc. Furthermore, IoT offers a well-                  either be constant (preset) or variable.
established arrangement of restricted resources             This number is flexible in the
ensuring that the greatest usage of IoT                     methods which randomly select the
improves effectiveness. Figure 2 indicates a                CHs between the nodes.
schematic diagram displaying agricultural
                                                           Cluster size: The size of the clusters
designs that deliver easy and cost-effective
                                                            may be identical or inequitable,
connexions across individual Greenhouse,
                                                            depending      on     the     uniform
Livestock, and Field monitoring through
                                                            dissemination of the load amongst all
secure and perfect connectivity. The figure
                                                            clusters    created.   The     cluster
indicates that two sensor kits have been
                                                            inequality is based on the distance
introduced to monitor soil humidity,
                                                            among sensor nodes and sink.
temperature, efficiency, and air flow [9].
                                                                                               284


       Intra-cluster communication: The                    become      more    common         than
        transmission inside a cluster can be                integrated methods.
        either precise or multi hop depending
                                                           CH selection: That clustering
        on the clustering algorithm. Some
                                                            algorithm has its own method for
        clustering approaches that involve
                                                            choosing a CH. But the CH selection
        multi-hop transmission among the CH
                                                            systems can generally be divided into
        and members when quantity of CHs is
                                                            three groups: fixed, random, and
        low and volume of the clusters high.
                                                            attribute based techniques. The CHs
       Inter-cluster communication: Because                are chosen in preset earlier nodes are
        the     nodes      have     small-range             deployed in the sector. The CHs are
        transmitters, the multi-hop solution is             chosen      randomly    in     random
        a suitable method. Nonetheless,                     strategies,     and    attribute-based
        several WSN applications presume                    processes pick them based on a few of
        that there is direct contact among the              their attributes, such as remaining
        CHs and the BS.                                     energy and distance from the sink.
CH properties                                              Algorithm complexity: It shows how
                                                            an algorithm converges. Several
Since the CH option is the key component of
                                                            algorithms converge based on the
each clustering algorithm, the selected CHs
                                                            requirements of the network such as
have a major impact on the efficiency. The
                                                            the amount of CHs and several
following features of the CHs are:
                                                            converge in a continuous time
       Mobility: The CHs can be static or                  irrespective of the requirements of the
        mobile. Mobile CHs can travel for a                 network.
        restricted distance but mobile CHs'
                                                           Clustering nature: Within the
        topology managing method is more
                                                            literature several clustering protocol
        complex than in a stationary CHs
                                                            have recommended for WSNs. A
        network.
                                                            limited number of such solutions are
       Node type: Compared to the normal                   based on the data centric system,
        nodes, the distributed CHs around the               known as reactive networks. Some of
        network may be rich in resources; that              the      solutions   suggested     are
        is, the network supports node                       constructive and do not embrace the
        heterogeneities or, the network may                 reactivity and some of them use a
        be similar, and regular nodes choose                mixture.
        the CHs.
                                                  4. Soft Computing Techniques based
       Role: The chosen CHs will play            Clustering Protocols
        different roles in the network,
        depending on the algorithm. Those         This section reviews the existing soft
        are relay and fusion functions.           computing techniques based clustering
                                                  protocols proposed for agriculture monitoring.
Clustering process
                                                  4.1 PSO
       Method: An algorithm for clustering
        can be either distributed, or             PSO [11] algorithm is a simulated by the
        centralized. Due to the fact that         collective conduct of bird gathering, and fish
        WSNs with a large amount of nodes,        schooling. It contains a swarm of particles N P
        disseminated    approaches    have        in search area, in which a particle i captures a
                                                  position X i , d and a velocity Vi , d in the d th
                                                                                                                                             285

dimension of global space. Throughout the                                                          transmission cost and improved location to
search area, each particle examines its                                                            solve the hot problem and to maximize the
personal best called pBesti and a global best                                                      network lifetime. The PSO-UFC therefore
                                                                                                   elects more MCHs in region closer to the BS,
identified as gBest . After obtaining the pBesti
                                                                                                   so that the MCHs nearer to the BS have lesser
and        gBest ,            Pi        revises its velocity and                                   cluster sizes to save their energy for maximum
position in every iteration by utilizing equation                                                  relay traffic. Through using unequal clustering
(1) and (2) respectively.                                                                          method, the PSO-UFC effectively balances
                                                                                                   energy consumption between the nodes and
Vi , d (t  1)  w  Vi ,d (t )  c1r1 ( pBesti ,d  X i ,d (t ))  c2 r2 ( gBest  X i ,d (t ))
                                                                                                   increases the existence of the network.
                                                                                          (1)
                                                                                                   4.2 Genetic Algorithm
X i , d (t  1)  X i , d (t )  Vi ,d (t  1)
                                                                                          (2)      GA is identified as an evolutionary approach,
                                                                                                   and it replicates the mechanism of growth to
where, w signifies the inertial weight, r1 , r2
                                                                                                   iteratively produce optimal resolution. The
signify random number and c1 , c2 show two                                                         flow diagram for GA appears in Figure 3. It
non-negative constants termed acceleration                                                         begins with the collection of randomly
factor generally set to 2.0. This procedure is                                                     produced individual population, known as
iteratively repetitive until a static amount of                                                    chromosomes based on unique information
iterations I max is achieved.                                                                      about the challenge. -- chromosome is an
                                                                                                   collection of genes containing a portion of the
Wang et al. [12] implemented a PSO-based
                                                                                                   solution. The fitness value is assessed on the
clustering procedure with a mobile BS known
                                                                                                   basis of the specific problem and in the next
as EPMS, to resolve the hop spot problem in
WSN. EPMS algorithm combines strategies                                                            generation the chromosomes linked with large
for the mobile BS and virtual clusters to                                                          fitness cost are selected for the reproduction
reduce delay and optimise system life. The                                                         procedure. In following step, chromosome
virtual clustering in the EPMS takes into                                                          recombination is attained using a crossover
account remaining energy and node position                                                         process to replicate different embryos.
for improved choice of CH. The mobile BS                                                           Crossover processing fuses the two parents'
transmits Hello packages to the CHs for                                                            genetic components to produce new offspring.
information group after cluster formation, and                                                     After fusion, the elected chromosomes go
the CH with high remaining energy is selected
                                                                                                   through a mutation procedure to produce new
for data transmission within its contact range.
                                                                                                   children by accidentally altering genes of
Results from the simulation indicate
substantial decrease in energy consumption                                                         specific chromosomes. When the population
and delay in transmission thus optimising                                                          converges so quickly, the mutation mechanism
network life. While the EPMS algorithm's                                                           restores any missing genetic values. This
fault-tolerant mechanism restores network                                                          would change the parent chromosomes with
connectivity by evaluating the broken path, it                                                     minimum fitness cost with a novel series of
may cause large overheads for communication                                                        genes generated utilizing crossover and
at the same time.                                                                                  mutation processes. This process is repeated
Kaur et al. [13] suggested a PSO-based                                                             till an optimal solution is attained [14].
clustering protocol with unequal and fault                                                         Rani et al. [15] Proposed an Improved
tolerance denoted as PSO-UFC in WSN. The                                                           vigorous clustering-associated approach and
protocol solves the problem of clustering and                                                      frame relay nodes (RN) to pick the most
fault tolerance for the network's long-run
                                                                                                   desired node in the cluster. A Genetic
service. It uses unequal clustering method to
                                                                                                   Analytics method is used for this purpose. The
stabilize energy utilization among the Master
CHs (MCHs) to resolve the hot spot issue. The                                                      simulations show that the recommended
BS manages to choose best MCHs with greater                                                        method affects the clustering algorithm
remaining energy, smaller intra-cluster                                                            Dynamic Clustering Relay Node (DCRN)
                                                                                                       286




                                   Fig. 4 Flowchart of Genetic Algorithm.

regarding slot consumption, throughput in                   engine as described in Fig. 4. The fuzzification
communication. In this study, a basic routing               component represents the input to the
method based on GA is intended to optimise                  respective fuzzy sets and designates
the performance metric of WSNs which helps                  membership level to each input set defined by
to escalate both theoretical analyses and                   a language such as "big," "low," "medium,"
simulations for IoT applications.         High              "small" and "huge." If-then rules are stored by
accessibility and productivity have been                    the fuzzy inference engine, by which the
increased in the system based on the execution              fuzzified values are mapped to linguistic
metrics of the Fitness function and the results             output variables with the support of rule base.
obtained are related through simulations. It is             The results achieved from the inference system
noted that proposed approach is a much better               are converted by defuzzification process like
solution associated with previously utilized                averaging approach, and centroid technique,
methods and in terms of network planning                    into the crisp values [16].
would be a novel development in IoT                         Pandiyaraju et al. [17] suggested a novel
applications.                                               intelligent routing protocol to enhance the
4.3 Fuzzy Logic                                             longevity of the network and to ensure energy
FL is a statistical method used to convey                   effectiveness to supply irrigation data. This
approximate human thought. Contrasting a                    new, smart routing protocol utilizes fuzzy
classic set theory in which results are either              rules is termed terrain dependent routing. The
real or false, FL produces intermediary values              inference method was utilized to take routing
according to laws of interpretation and                     choices. Two routing processes called Region
variables of language. A FL system contains                 Dependent Routing and Equalized CH
four essential parts, specifically fuzzification,           Election Routing were introduced and
defuzzification, a rule base and inference                  compared with the framework. The
                                                                                                         287

agricultural region in the first process is                  approach outperforms the recent traditional
divided into small areas of similar size called              protocols.
terrains. The nodes convey the data through                  Mahajan et al.[19] suggested an Effective and
multi-hop to the BS. In the second stage CH is               scalable protocol for distant monitoring of
chosen utilizing fuzzy rules that take into                  farms in rural areas, called the CL-IoT. A
account the distance to the sink and the                     cross-layer algorithm has been developed to
remaining energy. Ultimately, relay node                     minimise network transmission delay and
choice is performed utilizing Fuzzy rules.                   energy usage. The cross-layer dependent
Fuzzy laws are constructed using the                         optimal selection solution for the CH
remaining energy value, the distance from the                presented to resolve the energy irregularity
BS and the head-degree. From the simulation                  issue. The sensor's factors of dissimilar layers
outcomes it is noted that algorithm works                    such as a physical, MAC, and routing layer
better in terms of lifespan, energy                          utilized to determine optimum CH. The
consumption than the other current algorithms.               nature-inspired procedure with a new
Rajput et al. [18] recommended a clustering                  probabilistic choice rule acts as a fitness value
algorithm focused on fussy methods to                        to determine the best path for data transfer.
enhance WSN's stability. Fuzzy methods are                   The performance of CL-IoT is evaluated by
employed to resolve inconsistencies that exist               using energy consumption, computational
in WSN. Clusters are created using the                       effectiveness, and QoS-effectiveness.
algorithm Fuzzy-c-means (FCM). The goal is
                                                             Yassine et al. [20] suggested a Fuzzy-based
to cluster the sensors appropriately to
                                                             clustering methodology applied to agriculture.
minimise contact gaps in the intra-cluster. It
                                                             The authors utilized FCM procedure to boost
then selects the CHs based on the FL. The
                                                             the CH selection and cluster creation scheme.
efficiency of the protocol proposed for a rise in
                                                             Each node contributing in the CH selection
reporting region and node intensity is
                                                             assesses its fitness cost, which is expressed in
observed. It can be utilized for IoT-based
                                                             terms of node intensity, and energy utilization.
WSN, due to improved network reliability and
                                                             The cluster forming process also takes
sustainability. Compared to similar recent
                                                             advantage of FCM algorithms and effectively
traditional protocols, the proposed FCM
                                                             shapes clusters. The proposed procedure is
algorithm-based clustering maximizes the
                                                             contrasted with the existing routing protocols
lifetime in the event of a rise in node intensity.
                                                             by considering measurement metrics like the
As the contact gaps inside the intra-cluster are
                                                             quantity of live nodes, network energy usage
greatly reduced. The proposed clustering
                                                             and number of data packets collected by sink.
protocol offers reliable and sustainable
                                                             The presented procedure is evaluated by
network efficiency on different scenarios. The
                                                             performing multiple simulation experiments,
simulation results indicate that regarding
                                                             and all the plotted results are based on multiple
lifetime and energy efficiency the proposed
                                                             simulation test averages. It is clearly detected




                                           Fig. 4 Fuzzy Logic System.
                                                                                                 288

from the results obtained that the topology          From the results of the simulation, it is noted
achieves efficiently in both random and grid-        that the proposed protocol improves network
based network topology.                              lifespan, energy consumption than the other
                                                     current algorithms.
Rajput et al. [21] effort is produced to project a
clustering algorithm to achieve balanced WSN         4.4 Artificial Neural Networks
while optimising node intensity and exposure
area. The main goal is to maximise energy            A neural network is a wide interconnected
productivity by dropping the space of nodes to       network of elements generated by the human
data transmission using the clustering               neurons. -- neuron conducts a small amount of
algorithm FCM. The next goal is to pick an           processes, and the total process is the weighted
effective CH node based on apparent                  number of these. A neural network must be
likelihood to achieve scalability. The outcomes      trained to generate the necessary outputs by a
attained suggest that the proposed protocol is       known collection of inputs. Training is
more energy effective than other related             typically achieved by feeding patterns of
approaches. Thus it can be used effectively in       teaching into the system and letting the
IoT systems for farm monitoring. FCM                 network change its weighting role according to
algorithm is implemented in order to shape           some previously established rules of learning.
optimum network clusters with Node positions         The learning may be supervised or
and cluster number are the inputs. It                unmonitored. An ANN essentially comprises
approximates cluster centre points for better        of three layers: input, hidden layer, and output,
cluster structure in surveillance property. This     where each layer can have numbers of nodes
greatly decreases the data communication             in it. This tests the output of the neural
distances between the nodes. The results             network against the desired output, and if the
demonstration that the protocol can shape            results are not as planned, the weights among
larger clusters to maximize the WSN lifetime.        layers are adapted and the procedure is
                                                     repeated until a very minor error remains [23].
Pandiyaraju et al. [22] suggested a new
intelligent routing algorithm to expand the          Thangaramya et al. [24] proposed a new IoT-
network lifetime and to deliver energy               based sensor network routing algorithm that
efficient routing. This new smart routing            uses a clustering approach based on neuro-
protocol utilizes fuzzy rules precision farming.     fuzzy rule to perform cluster-based routing to
This algorithm operates in three stages,             improve network presentation. In this method,
namely the phase of terrain forming, the phase       the cluster forming in WSNs used the energy
of election of Terrain Head and the phase of         modelling to proficiently route the packets by
routing based on terrain. The farmland in the        applying       machine        learning      using
first procedure is divided into small parts of       convolutionary NN with fuzzy weight
similar size known as terrains. In the next          adjustment laws, thus extending the lifetime of
phase CH is chosen utilizing fuzzy rules that        the network. The authors also considered four
take into account the distance to the sink and       elements, namely the remaining energy, the
the remaining energy. The TH which functions         distance among the CH and BS, the distance
as a relay transmits information from source to      among the node and the CH, and the CH-
sink. The relay node is chosen taking into           degree, that are essential features for the usage
account the residual resources, the departure        of energy and the lifetime of the network.
from the sink and the node-degree. But lastly,       They tested the proposed algorithm using
in the third step, relay node selection is           MATLAB simulations. The NFIS output value
performed utilizing fuzzy rules. The laws are        was utilized to establish the CH for the
constructed utilizing the residual energy, the       member node to meet. It has been observed
distance from the BS and the head-degree.            that the proposed protocol performed better
                                                                                                 289

regarding energy consumption and device life         of luciferin is correlated with the health of the
span because of the usage of neuro-fuzzy             actual location of the agent. The lighter
rules.                                               individual means better positioning (is a better
4.5 Harmony Search Algorithm                         solution). Using a probabilistic process, each
                                                     agent can only be attracted within the local-
Harmony Search (HS) is an important                  decision domain by a neighbour whose
evolutionary approach intended to imitate the        luciferin intensity is higher than his own, and
process of jazz musicians improvising. HS            then shift toward it [27].
creates random resolutions that are called
Harmony Memory. In each iteration a new              Li et al. [28] proposed a new paradigm of
solution is created and compared with the            cluster head selection to optimise network
worst resolution. It is substituted with the         lifespan and energy consumption. In addition,
severest resolution if new resolution is better.     this paper suggests a Glowworm swarm based
Phase continues until condition of termination       on Fitness with Fruitfly Algorithm (FGF),
is fulfilled. HS algorithm's strength lies in its    which is the hybridization of GSO and Fruitfly
capability to effectively arrive at global           Optimization Algorithm to pick the best CH in
solution. [25].                                      WSN. Despite this, GSO should deal with
                                                     non-linear problems; the model fails in solving
Bongale et al. [26] Two stage Chief Election         problems of large dimensions. The algorithm
Plan for the cluster. The quest algorithm for        also reduces the processing speed and has
harmony in the first stage is utilized to            limited local search capabilities. Similarly, in
evaluate energy efficient CHs which are              search space the FFOA algorithm also has
adequately divided by some ideal distance            drawbacks including lower convergence rate.
from each other. The tentatively chosen CH           Therefore it hybridises the best attributes of
are then enhanced by the firefly algorithm,          given algorithms to solve all the problems of
taking the parameters like node intensity,           the traditional algorithm. The proposed system
cluster density and energy consumption.              will minimise the negative search ability,
During the CH election method, all fireflies         while the enhanced search functionality can be
undergo a recursive update and estimation            used for convergence. Consequently, the
process before the CH are finalised. The             various goals were successfully addressed as
approach proposed guarantees that chosen             compared with the conventional algorithms.
CHs have high remaining energy and can
consume less energy in clustering. It also           4.7 Gravitational search algorithm
guarantees that clusters designed to have large      This approach is stimulated by Newton's laws
intensity, minimal transmission costs and            of movement and does not need a derivative to
chosen CHs are well disconnected from each           find fitness function solutions. The non-
other so that CHs include the whole sensing          convex fitness function can be extended to
area. The advantage of the proposed method of        random search algorithms which are
cluster creation is that the energy utilization is   differentiable. Masses are the agent in the
spread through the various network CHs.              GSA which can explore the feasible region.
4.6 Glowworm Swarm Optimization                      Each agent shows a solution to the problem of
                                                     optimisation where the value of each mass
In GSO, a colony of glowworms is initially           shows the modality of that solution assessed
distributed in solution space at random. --          by the function of fitness. Thus agents with
glowworm in search space represents a                higher mass values provide better solutions;
solution of objective function and carries along     they can entice other masses by gravitational
with it a certain amount of luciferin. The level     force. Thus, the agents' global movement is
                                                     towards a better solution [29].
                                                                                              290

Dhumane et al. [30] suggested a multi-             systems undergo the operations of crossover
objective fractional GSA to locate the             and mutation to generate stable offsprings. The
optimum CH for IoT. The Fractional GSA             clusters achieved from proposed GWO-GA is
(FGSA) is intended to locate the optimal CH        stable in terms of balancing network load, and
in the IoT network in an iterative way to          energy efficiency.
prolong the node's lifetime. In FGSA, the CH
                                                   Arikumar et al. [32] proposed an Energy
node is elected which is estimated by the
                                                   Efficient LifeTime Maximization (EELTM)
fitness value utilizing numerous goals like
                                                   methodology that uses PSO and FIS. PSO-
distance, linking duration and residual energy,
                                                   based fitness method to assess the fitness
called the multi-objective FGSA (MOFGSA).
                                                   function of every node, based on the main
The proposed technique comprises of two
                                                   energy, intensity and distance factors.
important       characteristics,    (1)     the
                                                   Additionally, an efficient CH – CR (cluster
implementation of a MOFGSA algorithm and
                                                   router) selection algorithm that utilizes the
(2) the creation of a novel fitness model with
                                                   fitness functions determined by PSO is
several goals to prolong the lifespan. The IoT
                                                   proposed to decide two optimum sensor nodes
network is initially shaped together with one
                                                   in every cluster to serve as CH and CR. The
or more sink nodes, with the greater quantity
                                                   elected CH collects the data entirely from its
of nodes. The FGSA algorithm contains both
                                                   associated members, while the CR is
the fractional principle and GSA which is used
                                                   responsible for collecting and transmitting the
to approximate agent power, velocity, and
                                                   data collected from its CH to the sink. So CH's
position. Then the fractional principle is
                                                   operating cost is lowered. Additional smart
understood with GSA to change the location of
                                                   strategy is that FIS can evaluate the radius for
the agent to optimally figure out CH. Thus, in
                                                   CH and divide the network into unbalanced
the proposed FGSA algorithm, the four
                                                   clusters. To evaluate the ability of EELTM,
multiple targets such as distance, latency and
                                                   parameters like residual-energy, FND and 50%
connect lifetime are used to measure novel
                                                   node die are used. Thus, the EELTM method
fitness cost. The MOFGSA thus ensures the
                                                   enlarges the network lifetime.
lifespan of the IoT nodes is extended.
                                                   Robinson et al. [33] proposed an Energy
4.7 Hybrid
                                                   Aware Clustering utilizing Neuro-fuzzy
Lipare et al. [31] combined two bio-inspired       method (EACNF) to generate energy efficient
techniques      specifically    Grey      Wolf     clusters in the network. The proposed structure
Optimization (GWO) and GA for balancing            comprises of a fuzzy and neural network
traffic load in agriculture-WSN. There is          which attains energy effectiveness in cluster
progress in the initial population process of      formation and CH election. EACNF utilized
both algorithms. The crossover and mutation        the neural network to deliver an appropriate
process has been improved to achieve the safe      training set for the energy and node density of
off-spring to improve the network's balanced       each sensor node in order to evaluation the
charge and effective energy usage. For             energy consumed by Unknown CHs. The
crossover operation, the authors substituted       nodes with higher residual energy are qualified
only the worst solution instead of switching all   to pick energy conscious cluster heads with
the parental solutions. This improves to save      different base station location. Fuzzy if – then
population's best option. In the mutation          mapping rule is utilized to form clusters and
process we modified the task of the node           CHs in the fuzzy logic component which
associated with the remote gateway to their        inputs. For WSN, EACNF is designed to
closest gateway instead of varying a random        manage Confidence factor for network
bit. This cuts the sensor node's energy            security. EACNF used three metrics like the
consumption. GWO and GA's best suited              range of transmission, the residual energy, and
                                                                                                         291

the Confidence aspect to enhance network                  Since the great potential of IoT in all phases of
lifetime.                                                 the latest life has been broadly recognized
                                                          sensors, wireless networks and software
4. Comparative analysis
                                                          applications have become an essential and
This section delivers a comparative study of              significant asset of modern agricultural
several soft computing techniques based                   structure. This paper surveys soft computing
clustering protocols in IoT-WSN. Table 1                  techniques     based     clustering     protocols
emphasizes the soft computing technique,                  employed in agriculture domain in WSN. The
clustering parameters, and transmission mode              importance of soft computing techniques in
of the reviewed clustering protocols. This                WSN reflects a thorough study of various
survey will also enable the researchers to                clustering schemes with focus on their goals.
rapidly analyse several soft computing                    The comparative analysis enables the selection
techniques reviewed in this paper and elect the           of suitable soft computing technique based
suitable soft computing technique based on                clustering schemes used in WSN to enable
their merits and limitations as given in Table            energy-efficient    aggregation      in     smart
2.                                                        agriculture system.

5. Conclusion


            Table 1: Comparative Analysis of Soft Computing Techniques Based Clustering Protocols


Protocols                  Soft Computing Technique Clustering Parameter             Transmission type

EPMS [12]                  PSO                        Residual energy, Location      Single hop

PSO-UFC [13]               PSO                        Residual energy, Intra-cluster Multi-hop
                                                      distance, Inter-cluster distance

DCRN-GA [15]               GA                         Residual energy,      Location, Multi-hop
                                                      Distance to BS

Pandiyaraju et al. [17]    Fuzzy logic                Distance   to   BS,   Residual Multi-hop
                                                      energy

Rajput et al. [18]         Fuzzy logic                Coverage area, Node density    Single hop

CL-IOT [19]                Fuzzy logic                Residual energy, distance to Multi-hop
                                                      BS

Yassine et al. [20]        Fuzzy logic                Node density, Cluster fairness, Multi-hop
                                                      Expected energy consumption

Rajput et al. [21]         Fuzzy logic                Node location, Number of Single hop
                                                      clusters

Pandivaraju et al. [22]    Fuzzy logic                Distance to the BS, Residual Multi-hop
                                                      energy

Thangaranga et al. [24]    Neural networks            Residual energy, distance Single hop
                                                      among CH and the BS,
                                                      Distance among sensor node
                                                      and CH
                                                                                              292


Bongale et al. [26]   HSA                        Node     density,   Cluster Single hop
                                                 compactness, Energy

Le et al. [28]        Glowworm            search Inter-cluster distance, Intra- Single hop
                      optimization               cluster distance, Energy

MOFGSA [30]           GSA                        Distance,    Link     lifetime, Single hop
                                                 Energy

Lipare et al. [31]    Grey wolf optimization,    Energy, Intra-cluster Distance, Single hop
                                                 Inter-cluster distance
                      GA

EELTM [32]            PSO, Fuzzy Logic           Energy, Distance, Density      Multi-hop


EACNF [33]            Neural   network,   fuzzy Energy, Density                 Single hop
                      logic
                                                                                                                    293


                                        Table 2 Summary of soft computing techniques

   Soft                                  Merits                                                  Limitations
Computing
Approaches
Fuzzy Logic     The implementation of FL needs minimum growth rate,
                 and design period.                                       Fuzzy laws are not flexible about the network changing
                The clustering protocols based on FL have the ability to aspects and needed to be re-learnt with vigorous
                 deal with contradictory conditions without needing any requirements.
                 complex statistical model.

Particle        PSO is used due to its simplicity to implement on  The iterative factor of PSO does not make it appropriate
swarm            software, and extremely optimum resolution.             for multimedia applications.
Optimization    PSO based clustering algorithms indicate considerable  PSO has significant memory limitation which involves
                 progress in terms of strength and flexibility           resource-rich BS.

Genetic         GA-based clustering proficiently resolve multi-objective  GA has sluggish convergence rate which limits its
Algorithm        problem where data regarding the network like network realization in multimedia applications.
                 topology, intensity, and dimension is not essential.      It does not have the capability to contract with dynamic
                                                                            system topology and transmission connection
                                                                            breakdowns.
Harmony         HS algorithm has relatively less parameters to calculate  For complex issues, HS is not effective in detecting the
search           the fitness value                                          global solution in large search space.
                It has the capability to detect areas with improved
                 results.
Neural          NNs can contract with inadequate data sets.               Unnecessary training may be needed in convoluted
Networks        NNs are effective in forecast.                             ANN systems

Glow worm  GSO does not utilize velocities, and hence has no  GSO has not applied for high dimensional challenges.
Swarm          difficulty as that related with velocity in PSO.
Optimization  The rate of convergence is maximum in possibility of
               discovering the global optimized response.
Gravitational  It involves only two parameters to adapt i.e. mass &  GSA has large computational cost.
Search          velocity to achieve near global optimal solution.     GSA has convergence issue if preliminary population
Algorithm                                                              not created well
                                                                                                   294

                                                          Wireless Personal Communications, 107(1),
    References                                            pp.471-512.
                                                      10. Afsar, M. M., & Tayarani-N, M. H. (2014).
1. Muangprathub,        J.,     Boonnam,        N.,       Clustering in sensor networks: A literature
   Kajornkasirat,    S.,     Lekbangpong,       N.,       survey. Journal of Network and Computer
   Wanichsombat, A. and Nillaor, P., 2019. IoT            Applications, 46, 198-226.
   and agriculture data analysis for smart farm.      11. Poli, Riccardo, James Kennedy, and Tim
   Computers and electronics in agriculture, 156,         Blackwell. "Particle swarm optimization."
   pp.467-474.                                            Swarm intelligence 1, no. 1 (2007): 33-57
2. Sadowski, S. and Spachos, P., 2020. Wireless       12. Wang, Jin, Yiquan Cao, Bin Li, Hye-jin Kim,
   technologies for smart agricultural monitoring         and Sungyoung Lee. "Particle swarm
   using internet of things devices with energy           optimization based clustering algorithm with
   harvesting capabilities. Computers and                 mobile sink for WSNs." Future Generation
   Electronics in Agriculture, 172, p.105338.             Computer Systems 76 (2017): 452-457.
3. Sanjeevi, P., Prasanna, S., Siva Kumar, B.,        13. Kaur, T. and Kumar, D., 2018. Particle swarm
   Gunasekaran, G., Alagiri, I. and Vijay Anand,          optimization-based unequal and fault tolerant
   R., 2020. Precision agriculture and farming            clustering protocol for wireless sensor
   using Internet of Things based on wireless             networks. IEEE Sensors Journal, 18(11),
   sensor network. Transactions on Emerging               pp.4614-4622.
   Telecommunications Technologies, p.e3978.          14. Mirjalili, S., 2019. Genetic algorithm. In
4. V. Bhandary, A. Malik, and S Kumar,                    Evolutionary algorithms and neural networks
   “Routing in Wireless Multimedia Sensor                 (pp. 43-55). Springer, Cham.
   Networks: A Survey of Existing Protocols and       15. Rani, S., Ahmed, S.H. and Rastogi, R., 2019.
   Open     Research      Issues,”    Journal    of       Dynamic clustering approach based on
   Engineering, pp. 1-27, 2016.                           wireless sensor networks genetic algorithm for
5. J. Yick, B. Mukherjee, and D. Ghosal,                  IoT applications. Wireless Networks, pp.1-10.
   “Wireless sensor network survey,” Computer         16. Barros, L.C.D., Bassanezi, R.C. and Lodwick,
   networks, Vol.. 52, no 12, pp. 2292-2330,              W.A., 2017. A first course in fuzzy logic,
   2008.                                                  fuzzy dynamical systems, and biomathematics:
6. Dhasian, H.R. and Balasubramanian, P., 2013.           theory and applications.
   Survey of data aggregation techniques using        17. Pandiyaraju, V., Logambigai, R., Ganapathy,
   soft computing in wireless sensor networks.            S. and Kannan, A., 2020. An Energy Efficient
   IET Information Security, 7(4), pp.336-342.            Routing Algorithm for WSNs Using
7. Sharma, R., Vashisht, V. and Singh, U., 2020.          Intelligent Fuzzy Rules in Precision
   Soft Computing Paradigms Based Clustering              Agriculture.         Wireless         Personal
   in Wireless Sensor Networks: A Survey. In              Communications, pp.1-17.
   Advances in Data Sciences, Security and            18. Rajput, A. and Kumaravelu, V.B., 2020. FCM
   Applications    (pp.     133-159).     Springer,       clustering and FLS based CH selection to
   Singapore.                                             enhance sustainability of wireless sensor
8. Farooq, M.S., Riaz, S., Abid, A., Abid, K. and         networks for environmental monitoring
   Naeem, M.A., 2019. A Survey on the Role of             applications. Journal of Ambient Intelligence
   IoT in Agriculture for the Implementation of           and Humanized Computing, pp.1-21.
   Smart Farming. IEEE Access, 7, pp.156237-          19. Mahajan, H.B., Badarla, A. and Junnarkar,
   156271.                                                A.A., 2020. CL-IoT: cross-layer Internet of
9. Thakur, D., Kumar, Y., Kumar, A. and Singh,            Things protocol for intelligent manufacturing
   P.K., 2019. Applicability of wireless sensor           of smart farming. Journal of Ambient
   networks in precision agriculture: A review.           Intelligence and Humanized Computing, pp.1-
                                                          15.
                                                                                                    295

20. Yassine, S. and Fatima, L., 2019, October.           Algorithms.          Wireless           Personal
    Dynamic Cluster Head Selection Method for            Communications, 106(2), pp.275-306.
    Wireless Sensor Network for Agricultural         27. Krishnanand, K.N. and Ghose, D., 2009.
    Application of Internet of Things based Fuzzy        Glowworm swarm optimization for searching
    C-means Clustering Algorithm. In 2019 7th            higher dimensional spaces. In Innovations in
    Mediterranean             Congress          of       Swarm Intelligence (pp. 61-75). Springer,
    Telecommunications (CMT) (pp. 1-9). IEEE.            Berlin, Heidelberg.
21. Rajput, A. and Kumaravelu, V.B., 2019.           28. Li, Z. and Huang, X., 2016. Glowworm swarm
    Scalable and sustainable wireless sensor             optimization and its application to blind signal
    networks for agricultural application of             separation. Mathematical Problems in
    Internet of things using fuzzy c-means               Engineering, 2016.
    algorithm. Sustainable Computing: Informatics    29. Rashedi, E., Nezamabadi-Pour, H. and
    and Systems, 22, pp.62-74.                           Saryazdi, S., 2009. GSA: a gravitational search
22. Pandiyaraju, V., Logambigai, R., Ganapathy,          algorithm. Information sciences, 179(13),
    S. and Kannan, A., 2020. An Energy Efficient         pp.2232-2248.
    Routing Algorithm for WSNs Using                 30. Dhumane, A.V. and Prasad, R.S., 2019. Multi-
    Intelligent Fuzzy Rules in Precision                 objective fractional gravitational search
    Agriculture.          Wireless        Personal       algorithm for energy efficient routing in IoT.
    Communications, pp.1-17.                             Wireless networks, 25(1), pp.399-413.
23. Goldberg, Y., 2017. Neural network methods       31. Lipare, A., Edla, D.R., Cheruku, R. and
    for natural language processing. Synthesis           Tripathi, D., 2020. GWO-GA Based Load
    Lectures on Human Language Technologies,             Balanced and Energy Efficient Clustering
    10(1), pp.1-309.                                     Approach for WSN. In Smart Trends in
24. Thangaramya,       K.,     Kulothungan,    K.,       Computing and Communications (pp. 287-
    Logambigai, R., Selvi, M., Ganapathy, S. and         295). Springer, Singapore.
    Kannan, A., 2019. Energy aware cluster and       32. Arikumar, K.S., Natarajan, V. and Satapathy,
    neuro-fuzzy based routing algorithm for              S.C., 2020. EELTM: An Energy Efficient
    wireless sensor networks in IoT. Computer            LifeTime Maximization Approach for WSN
    Networks, 151, pp.211-223.                           by PSO and Fuzzy-Based Unequal Clustering.
25. Lee, K.S. and Geem, Z.W., 2004. A new                Arabian Journal for Science and Engineering,
    structural optimization method based on the          pp.1-16.
    harmony search algorithm. Computers &            33. Robinson, Y.H., Julie, E.G., Balaji, S. and
    structures, 82(9-10), pp.781-798.                    Ayyasamy, A., 2017. Energy aware clustering
26. Bongale, A.M., Nirmala, C.R. and Bongale,            scheme in wireless sensor network using
    A.M., 2019. Hybrid Cluster Head Election for         neuro-fuzzy approach. Wireless Personal
    WSN Based on Firefly and Harmony Search              Communications, 95(2), pp.703-721.