One laptop per child: Vision vs. reality

Nicholas Negroponte presents the idea of One Laptop Per Child (OLPC), a $100 PC that can transform education for the world's disadvantaged school children. The nonprofit OLPC project involves$20 million in startup investment, sponsorships and partnerships with major IT industry players, and interest from developing countries. Some developing countries are deploying OLPC laptops, while some have cancelled the deployments on the results of pilot projects. The OLPC organization (www.olpc.com) is also struggling with key staff defections, budget cuts, and ideological disillusionment. OLPC is also motivating the PC industry to develop lower-cost, education-oriented PCs, and providing developing countries with low-cost computing options along with its own innovation. OLPC also has developed a novel technology, the XO laptop, with a focus on the needs of students in poor rural areas

One Laptop Per Child (OLPC): A novel computerization movement?

This study applies concepts about computerization movements (CMs) to a case study of the diffusion of innovation in the developing world and thereby to draw lessons for undertaking similar technology projects. We identify the key characteristics of a computerization movement in the scholarly literature and then review the One Laptop Per Child (OLPC) Project in terms of each, identifying where OLPC adds new understanding about CMs. The OLPC project is an example of a computerization movement that has launched a new generation of low-cost computers in the developing world, while failing in its own ambitious goals. The OLPC project provides insights into the nature of computerization movements, in particular the process of mobilization, the diffusion of innovations in the developing world, and the overlap of multiple movements. OLPC's limited success to date illustrates the importance of having: (1) financial resources beyond deployment for economic sustainability, (2) local skills, infrastructure and deployment capability for operational sustainability, and (3) a replicable and scalable deployment model for ease of implementation across many sites. © 2011 IEEE

Invariant Synthesis for Incomplete Verification Engines

We propose a framework for synthesizing inductive invariants for incomplete verification engines, which soundly reduce logical problems in undecidable theories to decidable theories. Our framework is based on the counter-example guided inductive synthesis principle (CEGIS) and allows verification engines to communicate non-provability information to guide invariant synthesis. We show precisely how the verification engine can compute such non-provability information and how to build effective learning algorithms when invariants are expressed as Boolean combinations of a fixed set of predicates. Moreover, we evaluate our framework in two verification settings, one in which verification engines need to handle quantified formulas and one in which verification engines have to reason about heap properties expressed in an expressive but undecidable separation logic. Our experiments show that our invariant synthesis framework based on non-provability information can both effectively synthesize inductive invariants and adequately strengthen contracts across a large suite of programs

Sharper and Simpler Nonlinear Interpolants for Program Verification

Interpolation of jointly infeasible predicates plays important roles in various program verification techniques such as invariant synthesis and CEGAR. Intrigued by the recent result by Dai et al.\ that combines real algebraic geometry and SDP optimization in synthesis of polynomial interpolants, the current paper contributes its enhancement that yields sharper and simpler interpolants. The enhancement is made possible by: theoretical observations in real algebraic geometry; and our continued fraction-based algorithm that rounds off (potentially erroneous) numerical solutions of SDP solvers. Experiment results support our tool's effectiveness; we also demonstrate the benefit of sharp and simple interpolants in program verification examples

A Survey of Satisfiability Modulo Theory

Satisfiability modulo theory (SMT) consists in testing the satisfiability of first-order formulas over linear integer or real arithmetic, or other theories. In this survey, we explain the combination of propositional satisfiability and decision procedures for conjunctions known as DPLL(T), and the alternative "natural domain" approaches. We also cover quantifiers, Craig interpolants, polynomial arithmetic, and how SMT solvers are used in automated software analysis.Comment: Computer Algebra in Scientific Computing, Sep 2016, Bucharest, Romania. 201

Immunomodulatory potential of a bioactive fraction from the leaves of Phyllostachys bambusoides (Bamboo) in Balb/c mice

In order to evaluate the role of ethyl acetate fraction (PB-EtAC) obtained from the Phyllostachys bambusoides leaves in the modulation of immune responses, detailed studies were carried out using a panel of in vivo assays. Oral administration of PB-EtAC (50–200 mg/Kg) stimulated the IgM and IgG titre expressed in the form of haemagglutination antibody (HA) titre. Further, it elicited a dose related increase in the delayed type hypersensitivity reaction (DTH) after 24 and 48 h in BALB/c mice. Besides augmenting the humoral and cell mediated immune response, the concentration of cytokines (IFN-γ, IL-2, and IL-4) in serum with respect to T cell interactions also increased significantly. It also induced macrophage phagocytosis, and nitric oxide (NO) production which resulted in a high degree of protection against Candida albicans and carbon clearance. Moreover, the enhancement in CD4 and CD8 cell populations as revealed by flow cytometry. Taken together this in vivo and ex vivo preclinical data, our results suggested that PB-EtAC acts as an effective immunostimulator eliciting both Th1 and Th2 immune responses. We are reporting first time the immunostimulatory potential of P. bambusoides and it might be regarded as a biological response modifier

Unusual acquired gastric outlet obstruction during infancy: a case report

Acquired gastric outlet obstruction (GOO) during infancy beyond the neonatal period is a very rare condition when other congenital causes like infantile hypertrophic pyloric stenosis, antral diaphragm, pyloric atresia etc are excluded. We report an unusual case of 6 month old male child who presented with recurrent episode of vomiting not relieved by medication. On gastrograffin study there was pre pyloric stricture of unknown etiology and was managed by stricturoplasty. We are reporting this case because of its rarity and with excellent outcome if diagnosed and managed properly. Even on extensive search of English literature we are not able to find a single report of this lesion in infants

Effects of stitching on delamination of satin weave carbon-epoxy laminates under mode I, mode II and mixed-mode I/II loadings

The objective of the present study is to characterize the effect of modified chain stitching on the delamination growth under mixed-mode I/II loading conditions. Delamination toughness under mode I is experimentally determined, for unstitched and stitched laminates, by using untabbed and tabbed double cantilever beam (TDCB) tests. The effect of the reinforcing tabs on mode I toughness is investigated. Stitching improves the energy release rate (ERR) up to 4 times in mode I. Mode II delamination toughness is evaluated in end-notched flexure (ENF) tests. Different geometries of stitched specimens are tested. Crack propagation occurs without any failure of stitching yarns. The final crack length attains the mid-span or it stops before and the specimen breaks in bending. The ERR is initially low and gradually increases with crack length to very high values. The mixedmode delamination behaviour is investigated using a mixed-mode bending (MMB) test. For unstitched specimens, a simple mixed-mode criterion is identified. For stitched specimens, stitching yarns do not break during 25% of mode I ratio tests and the ERR increase is relatively small compared to unstitched values. For 70% and 50% of mode I ratios, failures of yarns are observed during crack propagation and tests are able to capture correctly the effect of the stitching: it clearly improves the ERR for these two mixed modes, as much as threefold