## 3 Autonomous System  
An autonomous system is one which identifies its operating environment and senses the operating parameters, transforms its behavior in that environment, and adapts to the situational changes of the environment [6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20]. Autonomic systems provide a means to address the system's complexities by employing technology to manage and control complex and dynamic systems. Such systems work with independent and predefined conditions, policies, rules _etc._ without human involvement. They can configure, optimize, manage, and control their actions based on predetermined conditions, rules, and acquired knowledge of the operating environment for a given period. The word autonomic originatesfrom the field of human biology. For instance, the autonomic nervous system in the human body monitors and controls our heartbeat, checks blood sugar levels, and regulates and maintains body temperature normal without human intervention. An autonomous self-aware system can be employed in wireless sensor network to solve routing of sensor data without human intervention. In autonomic computing, self-managing capabilities in the system are achieved by employing suitable actions according to situational changes that arise in a dynamic environment. The main goal of autonomic systems is to control the loop that sources and gathers detailed information from the environment, and then take appropriate actions. According to [PERSON] and [PERSON] [6], there are four characteristics of an autonomic system, as follows:  
**Self-Configuration:** In wireless sensor networks, self-configuration is the ability of sensor nodes to adapt dynamically to environmental and situational changes based on the predefined stated policies and rules that govern the operating environment. This entails the deployment of new sensors, removal of faulty components, or unpredicted situational changes that may arise in a dynamic environment. The use of dynamic adaptation provides continuous strength in sensing and enhances sensor node productivity, which gives rise to the scalability and flexibility of sensor networks. **Self-Healing:** This is one of the characteristic features of autonomic systems that provide the means for autonomic route discovery, fault detection, and recovery in wireless sensor networks. Such feature is the ability to discover, diagnose, and react to unpredicted situations that may arise in a dynamic environment. Self-healing sensor network components and routing techniques can detect network malfunction and initiate a route repair technique without affecting the entire sensor network. The route repair technique makes the network resilient against errors and faults. **Self-Optimization:** This attribute provides autonomic monitoring and control to facilitate fair and optimal use of available resources. Self-optimizing sensor components have the ability of controlling themselves to achieve the goals and policies stated in a given dynamic environment. Such control measures are the reallocation and rescheduling of available resources caused by arising situations in the dynamic environment in order to enhance overall network utilization and real-time transmission of sensory information. **Self-protection:** This characteristic of autonomic systems provides sensor networks with the capability of anticipating, detecting, identifying, and providing protection mechanisms against threats and other variant attacks. Self-protecting sensor components can detect malicious and suspicious behavior within the network, and take reactive measures to counterattack actions in order to make the network less vulnerable to threats. Self-protecting features of sensor network components provide security measures and policies to protect components and the entire network against any internal or external threats and vulnerability attacks.