Electrical resistivity tomography (ERT) is one of the most widely used geophysical methods in geological, hydrogeological, and geo-environmental investigations. Although 3D ERT is now available, 2D ERT remains state-of-the-practice due to its simplicity in fieldwork and lower space requirements. 2D ERT assumes that the ground condition is perpendicular to the survey line and outside the survey line is homogeneous. This assumption can often be violated in conditions such as geologic strikes not perpendicular to the survey line and topographic changes or buried objects near the survey line. Possible errors or artifacts in the 2D resistivity tomogram arising from violating the 2D assumption are often overlooked. This study aimed to numerically investigate the boundary effects on 2D ERT under various simplified conditions. Potential factors including resistivity contrast, depth and size of buried objects, and electrode spacing were considered for the parametric studies. The results revealed that offline geologic features may project onto the 2D tomogram to some extent, depending on the aforementioned factors. The mechanism and implications of boundary effects can be drawn from these parametric studies.

This paper presents the hybrid Taguchi genetic algorithm (HTGA) based on Maximum Power Point Tracking (MPPT) for photovoltaic (PV) system with buck converter. HTGA has been proved that have better ability in many situation than genetic algorithm (GA), although HTGA does complex than GA. GA have extreme activity to the global variable and unlikely get into local optimal solution. However, GA is not very stable and sometimes still get the local optimal solution. HTGA not only have better ability than GA, but also enhance the calculation ability of global variables. Though HTGA mostly apply in other application, and it is rarely used in the MPPT of solar energy systems. Therefore, HTGA will introduce into the PV system to find the MPPT this paper. In addition to perturb and observe (P&O), incremental conductance method and many others algorithm, this study use HTGA to replace those method in MPPT. The present study can see HTGA have improved the PV system to have better performance ability.