Teguh Prakoso

The depletion influence on the non-planar vertical MOSFET threshold voltage

The continuous scaling of transistors in nano scale leads to the invention of more sophisticated devices which may possess non-planar structures. As a consequence, the model for respective devices is of importance in order to predict the performance and behaviour throughout its operation. In non-planar structure, the thickness of silicon layer strongly affects the overall performance of the device. In this paper, we investigate the influence of depletion in the silicon layer of vertical MOSFET and develop an analytical model for devices with vertical pillar using parabolic approximation. The model for floating body channel structure which may form either partial or fully depleted channel was developed and elaborated as well. The simulation result shows the shift in threshold voltage characteristics with the different depletion widths and pillar thicknesses in the variation of channel length.

Development of Bio-impedance Analyzer (BIA) for Body Fat Calculation

Common weight scales cannot assess body composition or determine fat mass and fat-fress mass that make up the body weight. This research propose bio-impedance analysis (BIA) tool capable to body composition assessment. This tool uses four electrodes, two of which are used for 50 kHz sine wave current flow to the body and the rest are used to measure the voltage produced by the body for impedance analysis. Parameters such as height, weight, age, and gender are provided individually. These parameters together with impedance measurements are then in the process to produce a body fat percentage. The experimental result shows impressive repeatability for successive measurements (stdev ≤ 0.25% fat mass). Moreover, result on the hand to hand node scheme reveals average absolute difference of total subjects between two analyzer tools of 0.48% (fat mass) with maximum absolute discrepancy of 1.22% (fat mass). On the other hand, the relative error normalized to Omrons HBF-306 as comparison tool reveals less than 2% relative error. As a result, the system performance offers good evaluation tool for fat mass in the body.

Design of self balancing pitch control in fixed wing unmanned aerial vehicle with fuzzy logic controller

In UAV flight controllers design, the occurrence of errors due to the delay in the system response to the reference signal from the pilot and the lack of stability in flat conditions due to interference or unbalanced mechanical load. When this happens UAV can not be controlled and the flight conditions can not be maintained any more. Fuzzy controller offers a solution for the development of UAVs stability controllers, specialized in the design of the autopilot system that controls the pitch angle of the UAV. This research has been developing a prototype of fixed wing UAV that can be controlled wirelessly and has ability to maintain the balance on the pitch angle of the flat conditions (self-balancing). Run test results show that the applied fuzzy method succesfully controls the pitch angle to maintain a flat condition the developed UAV.