Robust control of geared and direct-drive robotic manipulators under parameter and model uncertainties

Thesis (M.S.) University of Alaska Fairbanks, 2005The major contribution of this thesis is the design and evaluation of a chattering-free sliding mode controller (SMC), which is a novel application for 2 degree-of-freedom (DOF) planar robot arms exposed to load variations. The performance of the SMC is evaluated in comparison to a proportional-derivative-plus (PD+) controller, as an example of nonlinear model-based controllers, as well as classical linear controllers, such as proportional-derivative (PD) and proportional-integral-derivative (PID). The performance of all four methods has been tested via realistic and detailed simulation models developed for both geared and direct-drive type 2-DOF planar robot arms. The model used in simulations reflects the dynamics of the arm, as well as the actuator dynamics and pulse width modulation (PWM) switching of the power converters. Simulations are performed under unknown load variations for both step and sinusoidal type reference joint trajectories. The results demonstrate that the chattering-free SMC provides increased accuracy and robustness than that of the other controllers and requires no prior knowledge of the system dynamic model and the load variation that the end-effector is subjected to. The results obtained could be extended to the control of a variety of geared and direct-drive type robotic configurations.Introduction -- Modeling of 2-DOF planar elbow manipulator -- Control of 2-DOF planar elbow manipulator -- Simulation results -- Conclusions and future work -- References -- Appendix

Modeling and validation of L-asparaginase enzyme, an anticancer agent using the tools of computational biology

Background: The L-Asparaginase is a medically important drug. The L-Asparaginase enzyme, an anticancer agent produced by microorganisms is used for the treatment of patients suffering from lymphoma and leukemia. The L-Asparaginase is economical and its administration is easy when compared to other commercial drugs available in market. Many microbes have been reported to produce the L-Asparaginase.Methods: In the present work the sequence of L-Asparaginase enzyme protein was obtained from the Universal Protein Resource (UNIPROT) server. The sequence of L-Asparaginase was used to generate 3-D model of L-Asparaginase in SWISS MODEL server. The constructed L-Asparaginase model was verified using Ramachandran Plot in PROCHECK server.Results: The FASTA format of L-Asparaginase enzyme of Bacillus subtilis strain 168 was retrieved from UNIPROT server. The FASTA format of L-Asparaginase was submitted to SWISS MODEL and its three-dimensional structural model was developed based on relevant template model. The model structure of L-Asparaginase was validated in PROCHECK server using Ramachandran Plot. The Ramachandran Plot of L-Asparaginase model inferred the reliability of L-Asparaginase structure model developed in SWISS MODEL server.  Conclusions: In the present study computational tools were exploited to develop and validate a potent anticancer drug, L-Asparaginase. Further the modeled L-Asparaginase enzyme protein can be improved using advanced bioinformatics tools and the same improved enzyme can be produced by improving the L-Asparaginase producing microbial strains by site-directed mutagenesis in the corresponding gene

PERFORMANCE ANALYSIS OF SRCP IMAGE BASED SOUND SOURCE DETECTION ALGORITHMS

Steered Response Power based algorithms are widely used for finding sound source location using microphone array systems. SRCP-PHAT is one such algorithm that has a robust performance under noisy and reverberant conditions. The algorithm creates a likelihood function over the field of view. This thesis employs image processing methods on SRCP-PHAT images, to exploit the difference in power levels and pixel patterns to discriminate between sound source and background pixels. Hough Transform based ellipse detection is used to identify the sound source locations by finding the centers of elliptical edge pixel regions typical of source patterns. Monte Carlo simulations of an eight microphone perimeter array with single and multiple sound sources are used to simulate the test environment and area under receiver operating characteristic (ROCA) curve is used to analyze the algorithm performance. Performance was compared to a simpler algorithm involving Canny edge detection and image averaging and an algorithms based simply on the magnitude of local maxima in the SRCP image. Analysis shows that Canny edge detection based method performed better in the presence of coherent noise sources

Monotonic Response of RC Exterior Beam-Column Joints Reinforced with Filler-Modules and FRP Composite Wraps/Gussets

A review of post-earthquake reconnaissance studies revealed that reinforced concrete (RC) structures, designed and built before the development of Uniform Building Code (UBC) seismic design guidelines in 1976, have suffered complete collapse or severe damages due to the brittle failure of exterior beam-column joints. Over the past 50 years, several studies were conducted to strengthen exterior joints of in-service structures, with limited emphasis on developing simple, economic and durable repair strategies to improve energy absorption through large inelastic joint deformations. Even less emphasis was devoted to developing repair procedures that minimize stress-concentrations at joint corners and enhancing the strength, ductility, and energy dissipation capabilities of concrete structures with an emphasis on joint resistance improvements. To address the above limitations, a novel approach of reinforcing vulnerable joints with filler-modules and fiber-reinforced polymer (FRP) composite wraps/gussets have been proposed and evaluated, herein. The proposed approach involved bonding filler-modules at the reentrant corners of a joint and securing them with reinforcing dowels to minimize corner stress-concentrations through smoother stress transfer in and around a joint. Additionally, bonding of FRP composite wraps or gussets on to the exposed beam-column faces was done to reinforce the joint core, thus enhancing the strength and energy absorption through joint confinement and reducing joint shear demand so that the plastic hinge could form away from the joint core. To investigate the efficacy of the proposed approach in enhancing the joint structural capacities, twenty 2D RC exterior (T) joints were designed as per pre-1976 construction deficiencies and experimentally evaluated in control (as-built) and reinforced conditions through the variations in (i) filler-module geometric shape; (ii) filler-module material properties, (iii) FRP material, (iv) FRP wrap/gusset configurations, (v) confinement due to partial (U-anchors) versus complete (360o-anchors) diagonal wraps, and (vi) shear transfer through reinforcing dowels. The performance of the test specimens was recorded through numerical values of loads versus deformation and strains at the rupture of concrete, de-bond of FRP wrap from the concrete surface, yielding of steel rebar, shear failure of column or joint panel through diagonal tension and beam flexural failure phenomena. Test data evaluations measured up to the peak loads revealed that the proposed approach of reinforcing joints with filler-modules and FRP wraps/gussets is immensely useful in enhancing the strength and ductility by ~300%, and energy dissipation by about 1200%. Depending upon the reinforcing scheme(s), the magnitude of failure- loads and patterns varied in a controlled manner. Joints tested in “control” condition exhibited shear failure through diagonal tension and diagonal compression while the strengthened specimens failed in beam flexure or column shear, but in a ductile manner through yielding of the column- or beam- rebars. The strains measured on rebar surfaces at different locations of joint- and beam- sections revealed a significant reduction in strain progression towards the joint panel (beam-column overlap). It was also noted that the use of low-stiffness filler-modules such as syntactic foam and engineered wood coupled with FRP wraps has tremendously enhanced the structural response of reinforced joints. It was also observed that joints reinforced with filler-modules and FRP wraps or gussets exhibiting beam flexural failure had more energy dissipation capacity when compared to specimens that failed in column shear. Based on the experimental results of reinforced joint specimens, joint behavior is characterized into three zones, i.e., A (onset of filler-module cracking), B (idealized yield - defined as the point beyond which a truss mechanism primarily resists the forces), and C (Peak load - referred to as a highest numerical value of load recorded during the testing). Furthermore, limit states (principal tension and shear) for joint at the onset of filler-module cracking (i.e., point A) and idealized yield (i.e., point B) have been established as a function of the concrete tensile strength ( ). The outcomes of this research have proven the ability of the proposed approach in strengthening concrete joints cost-effectively; thus, the overall structural integrity. Although the scope of this dissertation is limited to the evaluation of exterior beam-column joints designed before 1976, the concepts can be extended to other joint configurations, including timber and steel construction. Future research on the proposed approach must be directed towards evaluating the performance of joints with additional stiffness contributions from the slab, and transverse beams to establish joint curvature limit states. Furthermore, machine learning tools must be employed to train, evaluate, and develop strength prediction models after generating additional test data in a strategic sense with an understanding developed based on the current research. Besides, finite element analysis studies on joint inelastic behavior must be performed by incorporating material nonlinearity (post-cracking behavior of concrete joint or element) to arrive at the optimized shape of filler-modules and optimized fiber orientation of FRP wraps/gussets as a function of the substrate strength versus stiffness and bond strengths of glue lines of the substrate, filler-modules and FRP wrap or gusset

Drug disposing behavior and awareness of the concept of ecopharmacovigilance among the medical faculty

Background: The ever-increasing impact of drugs on the environment has added an altogether new dimension of monitoring, assessing and documenting the known and unknown drug effects on our fragile environment in the form of ecopharmacovigilance. This study was carried out to document the drug disposing behavior and awareness of the concept of ecopharmacovigilance among the medical faculty of a tertiary care Medical Hospital.Methods: A detailed, structured, anonymous questionnaire consisting of both open and close ended essential queries on drug disposal practices was prepared and response obtained from the participants which included an agglomeration of teaching faculty and the clinicians of various disciplines of the Institute.Results: 97.87% of the participants obtained drugs in excess which included a majority of solid (68.12%) and liquid (31.88%) dosage forms. The maximum medicines obtained in excess included analgesics and antipyretics (89.36%), anti-asthmatics (15.22%), and anti-emetics (13.48%). 82.8% of the respondents were unaware of the proper drug disposal technique and 94.7 % of the respondents practiced open disposal of the drugs.Conclusions: An abysmally low level of awareness about ecopharmacovigilance and unhealthy, irrational method of drug disposal was documented in our study. Appropriate training of those who handle drugs in hospitals and healthcare establishments is the need of the hour

Pain track analysis during gestation using machine learning techniques

During the gestation period women experience Braxton Hicks which is called the false labor, contractions during the second trimester. These contractions are not in regular intervals and also they are often unnoticed. The real labour or the true labour contractions develop late in the third trimester of the gestation usually beyond 36th week (excluding pre-term birth). Some women often fail to identify these pains in the third trimester of the gestation where an efficient facial recognition algorithm along with the support vector machine (SVM) helps them to identify these pains and take optimum care of themselves. The authors in this paper convey a mechanism to identify the pains effectively by creating a database of images pertaining to the pregnant women, her emotional states through out the pregnancy. Using MATLAB the algorithm of decision tree is implemented and the values obtained from them help us analyze the pain type efficiently

GSU Event Portal

The GSU EVENT PORTAL is website where you can advertise, view and make a booking for event by anywhere. You can do your necessary work related to events by this website just within few minutes. This application is trying to very easy for user to find venue by Google map. Many of the online event websites are not supported in the mobile phones, this is one of the main drawback in present online event websites. We may come across replication of data. To overcome the problem, we came with a new online event portal which supports in any windows, android, iOS, etc. Our website provides events like audio functions, company events, college events, sports events, traditional events, and more. We are providing Create, Modify, Delete events by user and also admin. We provide offers on ticket purchases. Our main intention is to reduce time and cost. We provide regular notifications regarding events. We provide security for your data. We are planning to launch this portal in July first week