# SIoT: A New Strategy to Improve the Network Lifetime with an Efficient Search Process
## 4 Our Proposal
### Main Steps
A node is a request to join as a member node to the node j (candidate master group) that has a high number of connections, if the node j has a high number of connections for all neighboring nodes such that it possesses a high capacity (for example residual energy is more than 50%), in this case, the node j responses positively for the node i. In the second scenario, when a node j sends a request to join as a member node and receives a request to be considered as the master node, node j will choose to be as member node and respond negatively to the request **(Rule 1)**. In the third scenario, when a new node has been deployed in an area, firstly, it gathers information from its neighbors, secondly, it sends a request to join the group that has a low number of members **(Rule 2)**. Rule (1) makes the network assemble a set of nodes that have low degrees within the node that has a high degree; its goal is to expand the proportion of connections when the social network is created. The objective of Rule (2) is to decrease the difference that exists between groups in terms of cardinality. During the discovery/search phase, the importance of groups is decreased, where each node has its own capability to realize tasks independently from its master group. The nature of groups is flexible in order to avoid some problems related to the creation of groups, such as nodes' mobility. Figure 3 provides an example of the groups' creation in a simple lossy network; there are four groups G1, G2, G3, and G4 with 9, 8, 7, and 8 nodes, respectively. The number of nodes in the groups does not exceed 9 (Gmax = 9). ### Available Resources and Search Factors

To determine the nature of the available resources of a network, node and group capabilities are proposed. Furthermore, the group centrality and popularity predict the search path of a request to achieve the provider rapidly. **Node capability:**

Node capability is a set of properties of a node such as quality of service, capacity of storage, power energy, etc. It combines all these properties and takes into account the weight of each property. We categorize the properties into two types:

_Maximized Property:_ when we want to select the best node, we search for a high value of certain properties such as power energy, memory capacity, etc. _Minimized Property:_ when we want to select the best node, we search for a low value of certain properties such as execution time, etc. We normalize the property \(\mathrm{p_{j}}\) of node \(\mathrm{i}\) by calculating the value of property \(\mathrm{v_{p_{j}}}\) which is given below:

\[\mathrm{v_{p_{j}}}=\left\{ \begin{array}{ll}1-\frac{1}{1+\mathrm{p_{j}}}&if \;\mathrm{p_{j}}\;is\;Maximized\;Property\\ \frac{1}{\mathrm{p_{j}}}&if\;\mathrm{p_{j}}\;is\;Minimized\;Property\end{array} \right. \tag{5}\]

where \(\mathrm{p_{j}}>0\) and \(0<\mathrm{v_{p_{j}}}\leq 1\)

The Equation (5) allows to limit the values of properties in range 0 and 1, and to determine their influence for each node. After that we define the node capability \(\mathrm{c_{i}}\) as follows:

\[\mathrm{c_{i}}=1-\frac{1}{1+\sum\limits_{j=1}^{\mathrm{n_{p}}}\mathrm{w_{j}} \mathrm{v_{p_{j}}}} \tag{6}\]

where \(\mathrm{w_{j}}\) is the weight of property \(\mathrm{p_{j}}\sum\limits_{j=1}^{\mathrm{n_{p}}}\mathrm{w_{j}}=1\), \(\mathrm{n_{p}}\) is the number of properties, and \(0<\mathrm{c_{i}}\leq 1\). Equation (6) combines all properties of a node with the weight of each property to determine the capability of the node using the normalized values obtained from Equation (5). Figure 3: An example of the node groups. The node with a high value of capability denotes a high efficiency. The most capable nodes are preferred to be master nodes or intermediate nodes. **Group capability:**

We define another factor related to the capability of a group, which is the capability of all nodes in the group (master node and member nodes).