Reconstructing null-space policies subject to dynamic task constraints in redundant manipulators

We consider the problem of direct policy learning in situations where the policies are only observable through their projections into the null-space of a set of dynamic, non-linear task constraints. We tackle the issue of deriving consistent data for the learning of such policies and make two contributions towards its solution. Firstly, we derive the conditions required to exactly reconstruct null-space policies and suggest a learning strategy based on this derivation. Secondly, we consider the case that the null-space policy is conservative and show that such a policy can be learnt more easily and robustly by learning the underlying potential function and using this as our representation of the policy.

Kerala Libraries Network (KELNET): a Proposal

Visualizes the conceptual framework and propose the development of a Kerala Library Network (KELNET) by exploring and exploiting the available and the existing social infrastructures, social softwares, open standards and technologies

A Rare Giant Pleural Thymoma in Posterior Mediastinum.

Thymoma is an epithelial neoplasm of the thymus, which commonly lies in the anterior mediastinum. Unusually, thymomas can also be found in other locations. Surgical excision, when feasible, appears to provide good results. We encountered a rare case of a thymoma that developed in the right thoracic cavity, and originating from the pleura in posterior mediastinum. We describe the clinical scenario, investigations, and our management of the patient

Calibration approach to electron probe microanalysis: A study with PWA-1480, a nickel base superalloy

The utility of an indirect calibration approach in electron probe microanalysis is explored. The methodology developed is based on establishing a functional relationship between the uncorrected k-ratios and the corresponding concentrations obtained using one of the ZAF correction schemes, for all the desired elements in the concentration range of interest. In cases where a very large number of analyses are desired, such a technique significantly reduces the total time required for the microprobe analysis without any significant loss of precision in the data. A typical application of the method in the concentration mapping of the transverse cross-section of a dendrite in directionally solidified PWA-1480, a nickel-based superalloy, is described

EFFECT OF STERCULIA FOETIDA BIODIESEL ON SINGLE CYLINDER FOUR STROKE DIESEL ENGINE PERFORMANCE AND EMISSIONS

In the present work, transesterified new biodiesel of sterculia foetida oil is mixed with diesel and the engine performance, combustion and emission was analysed. The primary objective work is to produce a new alternate and biodegradable fuel for compression ignition engine. The biofuel oil is an extract from sterculia foetida seed and transesterfied with 20 % methanol and 2 % KOH. The transesterfied biofuel concentrations were varied at 25%, 50%, 75% and 100% with diesel viz. B25, B50, B75 and B100. The engine is operated at different load conditions with different concentration of fuel. The experiments are conducted and the fuel blend B25 produces maximum of brake thermal efficiency in comparison with other biodiesel blends and produced maximum heat release and minimum emission produced at B25 biodiesel blend

Victim-Perpetrator Relationship: Reconnoitering Typology of Victimization in Anita Nair’s Eating Wasps

Violence against women is not new from feticide to cyberbullying. It remains unchanged and experienced by all ages of women from perpetrators in the patriarchal hegemony. Every form of violence affects millions of women’s lives irrespective of age, class, culture, language, religion, and education, and it cannot be stopped by anything due to deep-rooted patriarchy and gender stereotypes. Men (gender stereotypes) become the primary reason for the violence against women and women become vulnerable victims as they are considered ‘Other’, the weaker sex. Victimization has a physical and psychological impact on victims’ rest of their lives. Anita Nair, an Indian author vociferates the different forms of victimization in the modern era in her latest literary oeuvre Eating Wasps (2018). Megha, a six-year-old child, Liliana, an Italian spinster and Najma, a Muslim girl do not share any contribution to victimization but being in the hapless situation entitles them to be victimized. Yet, they are denied to accept the tag ‘victim’ and become survivors by fighting against the odds in their society. This study traverses the relationship between victims and perpetrators through the lens of Benjamin Mendelsohn’s typology of victimization and the challenges encountered by victims in the patriarchal environment.

Secondary arm coarsening and microsegregation in superalloy PWA-1480 single crystals: Effect of low gravity

Single crystal specimens of nickel base superalloy PWA-1480 were directionally solidified on ground and during low gravity (20 sec) and high gravity (90 sec) parabolic maneuver of KC-135 aircraft. Thermal profiles were measured during solidification by two in-situ thermocouples positioned along the sample length. The samples were quenched during either high or low gravity cycles so as to freeze the structures of the mushy zone developing under different gravity levels. Microsegregation was measured by examining the solutal profiles on several transverse cross-sections across primary dendrites along their length in the quenched mushy zone. Effect of gravity level on secondary arm coarsening kinetics and microsegregation have been investigated. The results indicate that there is no appreciable difference in the microsegregation and coarsening kinetics behavior in the specimens grown under high or low gravity. This suggests that short duration changes in gravity/levels (0.02 to 1.7 g) do not influence convection in the interdendritic region. Examination of the role of natural convection, in the melt near the primary dendrite tips, on secondary arm spacings requires low gravity periods longer than presently available on KC-135. Secondary arm coarsening kinetics show a reasonable fit with the predictions from a simple analytical model proposed by Kirkwood for a binary alloy