Development of hybrid force-position controller for ultrasound-guided breast biopsy robotic system

Conventional ultrasound-guided breast biopsy (UGBB) procedure is commonly performed to assess abnormal masses within the breast. It requires a radiologist to handle multiple devices at once, which could reduce the abilities in performing such procedure resulting in radiologist’s fatigue, compromised breast tissue due to multiple insertions and susceptibilities to pneumothorax complication for the patient. Previous studies have reported that many of the restrictions associated with handheld minimally invasive methods were tackled when physician assist instruments were used. Therefore, the purpose of this research is to assist radiologist in conventional UGBB procedure by introducing a semi-automated robotic system to maintain desired contact force between the ultrasound transducer and the breast. For that reason, a hybrid force/position controlled UGBB robotic system has been developed in simulation environment. The UGBB robotic system involves a 5 degree of freedom (DOF) articulated robot arm to control the transducer movement, a force/torque (F/T) sensor system to measure the contact force, an ultrasound machine to view the inside structure of the breast tissue and a computer-based control system. As such, the RV-2AJ robotic arm has been modelled with its positional accuracy of almost 100%. A breast model based on a medical grade breast phantom has been established with a mean error of 0.69% by using black-box modelling approach. Motion disturbance from human respiration has been explored as well since it plays a significant element that would affect the stability of the system to constantly maintain low contact force on the breast.Finally, intelligent Fuzzy-PID hybrid force/position controller has been successfully established to maintain low contact force on identified breast stiffness characteristics. The overall hardware-based simulation shows promising outcomes with almost no overshoot, fast rise time, high robustness and stability on different environment condition. In conclusion, the success of this work serves as significant foundations for long-term related research, especially in the development of UGBB robotic system and approaches of force control mainly for human-robot interaction

Dynamic leveling control of a wireless self-balancing ROV using fuzzy logic controller

A remotely operated vehicle (ROV) is essentially an underwater mobile robot that is controlled and powered by an operator outside of the robot working environment. Like any other marine vehicle, ROV has to be designed to float in the water where its mass is supported by the buoyancy forces due to the displacement of water by its hull. Vertically positioning a mini ROV in centimetres resolution underwater and maintaining that state requires a distinctive technique partly because of the pressure and buoyancy exerted by the water towards the hull and partly because of the random waves produced by the water itself. That being said, the aim of the project is to design and develop a wireless self-balancing buoyancy system of a mini ROV using fuzzy logic controller. A liquid level sensor has been implemented to provide feedback to the Arduino microcontroller. A user-friendly graphical user interface (GUI) has been developed for real-time data monitoring as well as controlling the vertical position of the ROV. At the end of the project, the implemented fuzzy control system shows enhanced and better performance when compared with one without a controller, a proportional-derivative (PD) controller, and a proportionalintegral-derivative (PID) controller

Finite element simulation of machining AISI 1045 steel using uncoated carbide tool

In recent years, finite element methods (FEM) have become widely used in research and industrial applications because of the advancements in computational efficiency and speed. FEM is a useful tool for the analysis of metal cutting process where this method provide better prediction of process variables whereas interaction of the tool and the chip can also be examined. Much cutting force models have been developed to predict the machining parameter. Most focus mainly on dry conditions even though coolants are widely used in practical machining. Research for modeling of minimal quantity lubricant (MQL) conditions is scarce and not really established. The use of coolants in machining makes it very difficult to determine the friction coefficient at the tool-chip interface. Hence, a better understanding of friction modeling is required in order to produce more realistic finite element models of machining process. In this study, a rigorous investigation on the role played by the implemented friction model within a 2D simulation was carried out. The simulation tool used for the purpose of this study is DEFORM2D. DEFORM 2D can simulate large deformation accompanied by elastic, plastic, thermal and friction effects. The simulation results on cutting forces and temperature were compared with experimental measurement in order to verify wether it is possible to identify the best friction model and indicate the consistency and accuracy of the results when conducting the comparison. From the result, it shows that friction models affect predicted result for both cutting force and temperature in dry and MQL conditions

The comparative study of studen’s achievement beetwen using Powerpoint learning media and module learning media of informatian and communication technology on ten grades of MAN 2 Yogyakarta of academic year 2012/2013

grades whose study using PowerPoint learning media and the student who are learning using module learning media in Information Technology and Communication (ICT) lesson at MAN 2 Yogyakarta. This research is done at MAN 2 Yogyakarta for Information Technology and Communication (ICT) lessons with material of second semester. This research is Quasi Experiment with pretest - posttest control group design. The sample of this study is two classes who totaled of 73 students, consist of 37 experiment class and 36 control student class. The experimental class is treated using PowerPoint learning media while the control class is treated using module learning media. The instrument used is pretest and posttest. Data where analyzed using student contribution (t-test). First, they are tested for normality and homogenity. The result shows that there is student achievement difference between using PowerPoint learning media and modul learning media. This is indicated by the difference (t (7874)> t table (1,667)) and the average of experimental class (83.18)> the average value of the control class (69.51). This comparison shows that the average of posttest experimental class is higher than the average of control class. There are differences in academic achievement between students who learn using PowerPoint learning media with the student who are learning using module, the learning achievement using PowerPoint instructional media better than learning to use the module. So that, learning achievement using Powerpoint learning media is better than learning using module learning media. Keywords: Media PowerPoint, Module, ICT Semester 2, Learning Achievemen

Range-Dependent Disorder Effects on the Plateau-Widths Calculated within the Screening Theory of the Iqhe

We summarize the screening theory of the integer quantized Hall effect (IQHE) and emphasize its two key mechanisms: first, the existence, in certain magnetic field intervals, of incompressible strips, with integer values of the local filling factor and quantized values of longitudinal and Hall resistivity, and second, the confinement of an imposed dissipative current to these strips, leading to the quantization of the global resistances. We demonstrate that, without any localization assumption, this theory explains the enormous experimental reproducibility of the quantized resistance values, as well as experimental results on the potential distribution in narrow Hall bars. We further demonstrate that inclusion of long-range potential fluctuations allows to apply the theory to wider Hall bars, and can lead to a broadening of the quantum Hall plateaus, whereas short-range disorder tends to narrow the plateaus.Comment: 10 pages, 4 figures, paper of the invited talk at Semi-Mag 17, Wuerzburg, German

The Interrelation between Incompressible Strips and Quantized Hall Plateaus

We study the current and charge distribution of a two dimensional electron gas under strong perpendicular magnetic fields within the linear response regime. We show within a self-consistent screening theory that incompressible strips with integer values of local Landau-level filling factor exist for finite intervals of the magnetic field strength $B$. Within an essentially local conductivity model, we find that the current density in these $B$ intervals is confined to the incompressible strips of vanishing local longitudinal resistivity. This leads to vanishing longitudinal and exactly quantized Hall resistance, and to a nice agreement of the calculated Hall potential profiles with the measured ones.Comment: 6 pages, 3 figure

The Real Powers of the Convolution of a Gamma Distribution and a Bernoulli Distribution

In this paper, we essentially compute the set of $x,y>0$ such that the mapping z \longmapsto \Big{(}1-r+r e^z\Big{)}^x \Big{(}\dis\frac{\lambda}{\lambda-z}\Big{)}^{y} is a Laplace transform. If $X$ and $Y$ are two independent random variables which have respectively Bernoulli and Gamma distributions, we denote by $\mu$ the distribution of $X+Y.$ The above problem is equivalent to finding the set of $x>0$ such that $\mu^{{\ast}x}$ exists.Comment: Please, i would submit our paper to math arxi

Adverse Selection, Emission Permits and Optimal Price Differentiation.

In this paper, we focus on the adverse selection issue that prevails in an economy when the regulator is not able to observe the type of the abate- ment costs of the firms. The regulator decides the total level of emission that minimizes the total social cost and he sells them to the firms at some di¤erentiated prices. When firms can hide their type relative to their true abatement costs, prices must not only minimize the social cost of the envir- onmental policy. They must also induce the firms to reveal their true type. A striking point of our model is that there is no participation constraint for firms are compelled to be actors of the environmental policy. Another original result concerns the rent, which still benefits to low-cost types, but which appears to be a fee paid by high-cost types.Regulation; adverse selection; emission permits; abatement costs; price differentiation.