Bilevel shared control for teleoperators

A shared system is disclosed for robot control including integration of the human and autonomous input modalities for an improved control. Autonomously planned motion trajectories are modified by a teleoperator to track unmodelled target motions, while nominal teleoperator motions are modified through compliance to accommodate geometric errors autonomously in the latter. A hierarchical shared system intelligently shares control over a remote robot between the autonomous and teleoperative portions of an overall control system. Architecture is hierarchical, and consists of two levels. The top level represents the task level, while the bottom, the execution level. In space applications, the performance of pure teleoperation systems depend significantly on the communication time delays between the local and the remote sites. Selection/mixing matrices are provided with entries which reflect how each input's signals modality is weighted. The shared control minimizes the detrimental effects caused by these time delays between earth and space

Dechalcogenative Allylic Selenosulfide And Disulfide Rearrangements For Cysteine Modification And Glycoligation

This thesis describes investigations directed at the development of methods for the selenosulfide and disulfide rearrangements for the permanent functionalization of thiols, and in particular of cysteine and carbohydrate based thiols. Emphasis is placed on the newly invented silver mediated allylic desulfurative rearrangement for the primary modification of thiols and the synthesis of complex oligosaccharide mimics. Chapter one introduces the concept of chemoselective ligations for the modification of macromolecules like carbohydrates and proteins. It overviews the native and non-native ligation techniques for their modification of such entities with a attention focusing on thiol based ligation techniques. The later part of chapter one describes the need for a permanent ligation technique for the thiol modification and draws attention to a novel method called the selenosulfide ligation. The second chapter describes studies focused on the further development of the selenosulfide rearrangement through selenocyanate methodology. The synthesis of various selenocyanates as convenient synthons for the selenosulfide ligation is described. The successful application of this selenosulfide methodology to the synthesis of tertiary allyl sulfides in which cysteine containing small peptides were modified with lipid units is highlighted. In the studies covered in chapter three, with the view to introducing farnesyl-like primary thio ether groups to cysteine peptides and electron deficient anomeric thiols, the allylic disulfide rearrangement was reassessed with the further goal of identifying phosphine-free reagents for the desulfurative rearrangement. This led to the invention of silver mediated allylic desulfurative rearrangement, which enabled the attachment of lipid groups to cysteine peptides and an anomeric thiol under mild reaction conditions. The protecting group-free synthesis of a glycoconjugate was accomplished using this methodology. In chapter four, extending the concept of this novel metal mediated allylic desulfurative rearrangement as a chemoselective ligation technique, for the synthesis of complex oligosaccharides is described with a focus to the synthesis of β-(1,3)-glucan surrogates. In chapter five, the experimental procedures and characterization data for the synthesized compounds are documented

Clostridium difficile and inflammatory bowel disease: implications for current clinical practice

Clostridium difficile infection should always be included in the differential diagnosis of patients with refractory inflammatory bowel disease (IBD) symptoms, as it is well known to induce or mimic a flare of IBD. There is currently an alarming increase in the incidence of C. difficile infection in Europe and North America. Current epidemiologic data suggest that more virulent strains, such as C. difficile 027/NAP1/BI, are emerging. Testing for both C. difficile toxins A and B should be done, and often serial stool samples may be required, especially if the index of suspicion is high. Patients with IBD do not necessarily require a history of antibiotic use or hospitalization to acquire the infection and most do not have pseudomembranes on sigmoidoscopy. C. difficile infection is associated with longer hospital stays, increased mortality, and higher complication rates, including colectomy. Treatment with oral vancomycin is probably the drug of choice as one study suggests that patients had lower colectomy rates on this drug. Further work is required to clarify the best management strategies for C. difficile in IBD patients, and more effort is needed to halt the rising incidence of this infection, perhaps with adherence to safer antibiotic prescribing guidelines, hand washing, and cleaner hospital environments, which should reduce the risk of acquiring and spreading this preventable infection

Sliding mode control method having terminal convergence in finite time

An object of this invention is to provide robust nonlinear controllers for robotic operations in unstructured environments based upon a new class of closed loop sliding control methods, sometimes denoted terminal sliders, where the new class will enforce closed-loop control convergence to equilibrium in finite time. Improved performance results from the elimination of high frequency control switching previously employed for robustness to parametric uncertainties. Improved performance also results from the dependence of terminal slider stability upon the rate of change of uncertainties over the sliding surface rather than the magnitude of the uncertainty itself for robust control. Terminal sliding mode control also yields improved convergence where convergence time is finite and is to be controlled. A further object is to apply terminal sliders to robot manipulator control and benchmark performance with the traditional computed torque control method and provide for design of control parameters

Antiulcer Activity of Indigenous Plant Operculina turpethum

In the Indian traditional system of medicine Operculina turpethum is commonly used to treat various ailments including peptic ulcer, inflammation, and pain. Ulcer preventive and ulcer protective activities of HAOP and MOP stem bark extracts of Operculina turpethum (100 mg/kg, b.w., orally) were evaluated employing aspirin + pylorus ligation (APL) model in experimental rats. The results suggested that both extracts (HAOP and MOP) possess enhanced ulcer preventive and protective activities when compared with the standard drug ranitidine. HAOP showed more pronounced effect when compared to MOP. Further the result of the histopathological and biochemical studies also confirms potent ulcer preventive and protective nature of a extracts in a similar manner

Multi-task learning with cross-task consistency for improved depth estimation in colonoscopy

Colonoscopy screening is the gold standard procedure for assessing abnormalities in the colon and rectum, such as ulcers and cancerous polyps. Measuring the abnormal mucosal area and its 3D reconstruction can help quantify the surveyed area and objectively evaluate disease burden. However, due to the complex topology of these organs and variable physical conditions, for example, lighting, large homogeneous texture, and image modality estimating distance from the camera aka depth) is highly challenging. Moreover, most colonoscopic video acquisition is monocular, making the depth estimation a non-trivial problem. While methods in computer vision for depth estimation have been proposed and advanced on natural scene datasets, the efficacy of these techniques has not been widely quantified on colonoscopy datasets. As the colonic mucosa has several low-texture regions that are not well pronounced, learning representations from an auxiliary task can improve salient feature extraction, allowing estimation of accurate camera depths. In this work, we propose to develop a novel multi-task learning (MTL) approach with a shared encoder and two decoders, namely a surface normal decoder and a depth estimator decoder. Our depth estimator incorporates attention mechanisms to enhance global context awareness. We leverage the surface normal prediction to improve geometric feature extraction. Also, we apply a cross-task consistency loss among the two geometrically related tasks, surface normal and camera depth. We demonstrate an improvement of 14.17% on relative error and 10.4% improvement on $\delta_{1}$ accuracy over the most accurate baseline state-of-the-art BTS approach. All experiments are conducted on a recently released C3VD dataset; thus, we provide a first benchmark of state-of-the-art methods.Comment: 19 page