## 4 Design of the SLS  
The Sustainable Load-balancing Scheme (SLS) can be divided by function into User Interface, Node Manager, Interaction Broker, Map Manager, Load Balancer, Map Controller, Coordinate Converter, and Viewer. Figure 3 presents a structure map of the overall function.  
Specifically, the User Interface, which is composed of the Node Interface, Load-balancer Set Interface, and Set-Simulation (SS), sets new sensor deployment for the current topology and simulates load-balancing; Start and Stop, which begin and end the SS operation, respectively; Save, which  
Figure 3: SLS architecture.  
saves the simulation setting condition; and Load, which brings back the previously saved simulation condition. The Sensor Node Information of the Node Interface receives user setting inputs regarding Unit and Location that represent sensor ID and sensor data type, Total Battery (TB), Active Power (AP), Active Time (AT), Sleep Power (SP), Sleep Time (ST), Current Battery (CB), Battery Consumption Rate (BCR), Start Time, Sensing Time, and Wakeup Time. Moreover, for basic sensor control, Sensing Range and Communication Range, Supersonic Wave Range, and Trace Range are determined.  
_Node Manager_ manages either by Mobile Sensor List (MSL) or Fixed Sensor List (FSL) according to the mobility of the deployed sensor nodes. Each sensor has routing data updated through the Load Balancer.  
_Interaction Broker_ plays the role of a broker that transfers the operation mode entered from the User Interface and the setting change of the sensor to the Map Controller, Node Manager, and Load Balancer.  
_Map Manager_ applies an actual topography and GML document that can be mapped to the SLS and managed. Specifically, it consists of a GML Importer that adds the GML document that was selected by the user to the SLS, the GML Parser that analyzes the added GML document, the Map Layer that forms the Map object by determining the existence of obstacles according to the object of the analyzed GML topography data and transfers them to the Layer Manager, and the Layer Manage that manages the topography information received from Map Layer.  
_Load Balancer_ manages the Sensor Objects in the Sensor Object List (SOL). The sensor objects in the SOL check the survival of the sensor and the arrival of the threshold that was determined by the user through the Sensor Audit Monitor. Once the threshold is reached, the Sensor Routing Information is changed to improve the overall topology lifespan. The changed information is transferred to the Node Manager.  
_Map Controller_ is in charge of zoom-in, zoom-out, range expansion, selective movement, _etc._ of the map that is visualized in the Viewer. These functional performance results are transferred to the Viewer through the Coordinate Converter to be visually shown to the user.  
_Coordinate Converter_ processes and transfers the operation condition data through the topography and the log information of sensor nodes such that they can be expressed in the Viewer.  
_Viewer_ visualizes the processed data transferred from the Coordinate Converter to the user based on their types. The Viewer is composed of the Mobile Viewer that visualizes dynamically moving sensor nodes, the Fixed Viewer that visualizes fixed sensor nodes, the Hybrid Viewer that shows both the Mobile Viewer and Fixed Viewer sensor nodes, and the Stats Viewer that visually expresses diverse analysis results regarding MSNs or FSNs. Through this Viewer, the user can check the load-balancing condition and deduct problems for the lifespan maximization of the overall topology according to the sensor deployment condition and actively respond to them.