To achieve a reasonable level of precision in tractor-based field operations, a tractor operator has to guide accurately, monitor and control both the tractor and the attached implement. Since guidance is the most time consuming task among the others, researchers have attempted to automate the guidance task. However, the use of automatic guidance and control in agricultural applications is not always appropriate. Transportation of the vehicle on a public road is an example of this. Some researchers therefore have focused on Vision-Aided methods to give some guidance aid to the driver rather than on eliminating the driver. To investigate the accuracy of such methods, a Vision-Aided tractor guidance belt-type Simulator was developed. An experimental prototype of the Simulator was constructed. To evaluate the prototype, a completely randomized factorial experiment was conducted with forward speed, heading angle, and camera tilt angle being the major factors under investigation. The Simulator performed satisfactorily at 5 and 7km/h and mean deviations of 1.14 and 2.31cm were obtained respectively.

Virtualization is a technique to make the cloud computations secure. This technique can reduce the costs and increase the reliability of systems by means of sharing the physical resources between several VMs (Virtual Machines). However, virtualized environments are vulnerable to some security issues such as lack of performance isolation. These days, using the virtualization as a technique is growing slowly in large organizations. Despite these advantages, virtualizations have created several security challenges. So, the main concern of virtualization service providers and their customers is how to detect and encounter these security challenges. In this research, the resource freeing attack is selected among all available virtualization attacks because of its simplicity and its drastic effects. Resource freeing attack causes an unfair resource distribution among VMs. We use Cloudsim as a powerful cloud simulation toolkit to implement resource freeing attack. After simulating the attack, the CPU's efficiency, response time diagrams, and the obtained bandwidth are measured. The simulation results show the significant changes in VM behavior after occurring the attack in the virtualized environment. These changes help cloud providers to detect resource freeing attack in the cloud.

Rain simulation is a method widely used in detecting hydrological and erosional processes. Most portable samples have inconvenient and challenging transport, high water consumption, and energy supply. The objective of this study was to design and test a rainfall Simulator characterized by the following innovative features: 1) The Simulator is easy to be transported and assembled in the field, thereby allowing the necessary experimental replicates, 2) Applicability on different slopes. The first calibration step regarded the spatial distribution of rainfall, the stability of the rainfall intensity, and the reproducibility of the rainfall intensities over time (among successive experiments). Next, the drop size distribution (DSD) and the related rainfall characteristics (median volumetric drop diameter D50 and mean kinetic energy per unit area and unit depth) were evaluated by the flour pellet method. A fluorescent tracer method is used to measure the velocity of falling drops. According to the findings, the Christiansen uniformity coefficient (Cu) of this rainfall Simulator varies from 77-87% for rainfall intensities of 35-75 mmh-1. The best rainfall distribution has been achieved for rainfall intensities of 55 and 75 mmh-1, with rain droplet sizes ranging from 0.6 to 3.8 mm. The raindrop velocity was also measured by photo-shooting and revealed a velocity rate of 2.7-5.7 ms-1. The system allows rainfall simulation on the fields and under laboratory conditions. Moreover, erosion, runoff, and sediment production under natural and intact soil conditions can also be examined with the highest possible accuracy