138 research outputs found
Tractable Reasoning In Knowledge Representation Systems
No full textThis dissertation addresses some problems raised by the well-known intractability of deductive reasoning in even moderately expressive knowledge representation systems. Starting from boolean constraint propagation (BCP), a previously known linear-time incomplete reasoner for clausal propositional theories, we develop fact propagation (FP) to deal with non-clausal theories, after motivating the need for such an extension. FP is specified using a confluent rewriting systems, for which we present an algorithm that has quadratic-time complexity in general, but is still linear-time for clausal theories. FP is the only known tractable extension of BCP to non-clausal theories; we prove that it performs strictly more inferences than CNF-BCP, a previously-proposed extension of BCP to non-clausal theories.
We generalize a refutation reasoner based on FP to a family of sound and tractable reasoners that are increasingly complete" for propositional theories. These can be used for anytime reasoning, i.e., they provide partial answers even if they are stopped prematurely, and the completeness" of the answer improves with the time used in computing it. A fixpoint construction based on FP gives an alternate characterization of the reasoners in this family, and is used to define a transformation of arbitrary theories into logically-equivalent vivid" theories | ones for which our FP algorithm ii is complete.
Our final contribution is to the description of tractable classes of reasoning problems. Based on FP, we develop a new property, called bounded intricacy, which is shared by a variety of tractable classes that were previously presented, for example, in the areas of propositional satisfiability, constraint satisfaction, and OR-databases. Although proving bounded intricacy for these classes requires domain-specific techniques (which are based on the original tractability proofs), bounded intricacy is one more tool available for showing that a family of problems arising in some application is tractable. As we demonstrate in the case of constraint satisfaction and disjunctive logic programs, bounded intricacy can also be used to uncover new tractable classes.Technical report DCS-TR-32
Study of structural and magnetic properties of cobalt ferrite nanoparticles sintered at different temperature
No full text
Optimization of Xylanase Production from Bacillus Sp. Pkd-9 under Solid State Fermentation, Partial Characterization and Application
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Glucoamylase from Bacillus sp. CAM-21: Production, immobilization and its application in food/agro waste saccharification.
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Studies on production and immobilization of mannanase from Bacillus sp.CAM-21 and preparation of β- Carotene nanoemulsions.
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Glucoamylase Production From Bacillus sp. CAM-21 Under Solid State Fermentation (SSF) and its Partial Biochemical Characterization.
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Dissolution rate improvement of telmisartan through modified MCC pellets using 32 full factorial design
No full textAbstractContext: Microcrystalline cellulose (MCC) is the most widely used excipient for the production of pellets but it retards the release of poorly water soluble drugs. Objective: The present investigation reports incorporation of camphor, cross carmellose sodium (CCS) and spray dried lactose (SDL) into MCC pellets to enhance the dissolution rate of telmisartan. Materials and methods: A full factorial design (32) was used in the study. Concentration of camphor and CCS was selected as independent variables whereas percentage porosity and percentage drug release at 60min were selected as dependent variables. Pellets were produced by extrusion–spheronization technique and evaluated for percentage yield, particle size analysis, flow characteristics, percentage porosity, drug content and in vitro drug release. Contour plots and 3-D surface plots were presented for graphical expression of the results. Results and discussion: Pellet formulations exhibited acceptable morphological, flow and mechanical properties. As against to 38.54% drug release after 60min with MCC pellets, pellets prepared with optimized formulation, composed of proper combination of MCC, SDL, camphor and CCS, released 100% drug after 60min. Conclusion: Our study underlines the fact that dissolution of telmisartan from MCC pellets can be successfully enhanced by incorporating water soluble excipient, disintegrant and pore formers
STUDIES IN OXCARBAZEPINE MICROSPHERES EMPLOYING PLACKETT AND BURMAN DESIGN
Get PDFObjective: The present work was aimed to screen material and processing parameters affecting encapsulation efficiency and drug release from microspheres.
Methods: Oxcarbazepine loaded microspheres were prepared employing multiple emulsion solvent evaporation technique. Ratio of chitosan to ethyl cellulose, ratio of drug to polymer, stirring speed, ratio of dichloromethane to methanol, amount of Span 80 and the volume of aqueous phase were selected as independent variables in the Plackett and Burman design. The microspheres were characterized for percentage yield, percentage encapsulation efficiency, particle size distribution and in vitro drug release.
Results: The critical material and processing parameters affecting encapsulation efficiency were chitosan to ethyl cellulose ratio, volume of water, stirring speed and drug to polymer ratio. Initial burst release was affected by volume of water, temperature, dichloromethane to methanol ratio, amount of Span 80 and drug to polymer ratio. FTIR study showed compatibility of the drug with excipients.
Conclusion: The outcome of the study shall be used to calculate risk priority number (RPN) and for devising suitable control strategies for the critical factors at industry
Exact explosive synchronization transitions in Kuramoto oscillators with time-delayed coupling
Get PDFSynchronization commonly occurs in many natural and man-made systems, from neurons in the brain to cardiac cells to power grids to Josephson junction arrays. Transitions to or out of synchrony for coupled oscillators depend on several factors, such as individual frequencies, coupling, interaction time delays and network structure-function relation. Here, using a generalized Kuramoto model of time-delay coupled phase oscillators with frequency-weighted coupling, we study the stability ofincoherent and coherent states and the transitions to or out of explosive (abrupt, first-order like) phase synchronization. We analytically derive the exact formulas for the critical coupling strengths at different time delays in both directions of increasing (forward) and decreasing (backward) coupling strengths. We find that time-delay does not affect the transition for the backward direction but can shift the transition for the forward direction of increasing coupling strength. These results provide valuable insights into our understanding of dynamical mechanisms for explosive synchronization in presence of often unavoidable time delays present in many physical and biological systems
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