Logical Concurrency Control from Sequential Proofs

We are interested in identifying and enforcing the isolation requirements of a concurrent program, i.e., concurrency control that ensures that the program meets its specification. The thesis of this paper is that this can be done systematically starting from a sequential proof, i.e., a proof of correctness of the program in the absence of concurrent interleavings. We illustrate our thesis by presenting a solution to the problem of making a sequential library thread-safe for concurrent clients. We consider a sequential library annotated with assertions along with a proof that these assertions hold in a sequential execution. We show how we can use the proof to derive concurrency control that ensures that any execution of the library methods, when invoked by concurrent clients, satisfies the same assertions. We also present an extension to guarantee that the library methods are linearizable or atomic

Safe Transferable Regions

There is an increasing interest in alternative memory management schemes that seek to combine the convenience of garbage collection and the performance of manual memory management in a single language framework. Unfortunately, ensuring safety in presence of manual memory management remains as great a challenge as ever. In this paper, we present a C#-like object-oriented language called Broom that uses a combination of region type system and lightweight runtime checks to enforce safety in presence of user-managed memory regions called transferable regions. Unsafe transferable regions have been previously used to contain the latency due to unbounded GC pauses. Our approach shows that it is possible to restore safety without compromising on the benefits of transferable regions. We prove the type safety of Broom in a formal framework that includes its C#-inspired features, such as higher-order functions and generics. We complement our type system with a type inference algorithm, which eliminates the need for programmers to write region annotations on types. The inference algorithm has been proven sound and relatively complete. We describe a prototype implementation of the inference algorithm, and our experience of using it to enforce memory safety in dataflow programs

Microelectromechnical Systems Inertial Measurement Unit Error Modelling and Error Analysis for Low-cost Strapdown Inertial Navigation System

This paper presents error modelling and error analysis of microelectromechnical systems (MEMS) inertial measurement unit (IMU) for a low-cost strapdown inertial navigation system (INS). The INS consists of IMU and navigation processor. The IMU provides acceleration and angular rate of the vehicle in all the three axes. In this paper, errors that affect the MEMS IMU, which is of low cost and less volume, are stochastically modelled and analysed using Allan variance. Wavelet decomposition has been introduced to remove the high frequency noise that affects the sensors to obtain the original values of angular rates and accelerations with less noise. This increases the accuracy of the strapdown INS. The results show the effect of errors in the output of sensors, easy interpretation of random errors by Allan variance, the increase in the accuracy when wavelet decomposition is used for denoising inertial sensor raw data.Defence Science Journal, 2009, 59(6), pp.650-658, DOI:http://dx.doi.org/10.14429/dsj.59.157

Tumors in von Hippel–Lindau Syndrome: From Head to Toe—Comprehensive State-of-the-Art Review

Von Hippel–Lindau syndrome (VHL) is an autosomal-dominant hereditary tumor disease that arises owing to germline mutations in the VHL gene, located on the short arm of chromosome 3. Patients with VHL may develop multiple benign and malignant tumors involving various organ systems, including retinal hemangioblastomas (HBs), central nervous system (CNS) HBs, endolymphatic sac tumors, pancreatic neuroendocrine tumors, pancreatic cystadenomas, pancreatic cysts, clear cell renal cell carcinomas, renal cysts, pheochromocytomas, paragangliomas, and epididymal and broad ligament cystadenomas. The VHL/hypoxia-inducible factor pathway is believed to play a key role in the pathogenesis of VHL-related tumors. The diagnosis of VHL can be made clinically when the characteristic clinical history and findings have manifested, such as the presence of two or more CNS HBs. Genetic testing for heterozygous germline VHL mutation may also be used to confirm the diagnosis of VHL. Imaging plays an important role in the diagnosis and surveillance of patients with VHL. Familiarity with the clinical and imaging manifestations of the various VHL-related tumors is important for early detection and guiding appropriate management. The purpose of this article is to discuss the molecular cytogenetics and clinical manifestations of VHL, review the characteristic multimodality imaging features of the various VHL-related tumors affecting multiple organ systems, and discuss the latest advances in management of VHL, including current recommendations for surveillance and screening

Typestate verification: Abstraction techniques and complexity results

AbstractWe consider the problem of typestate verification for shallow programs; i.e., programs where pointers from program variables to heap-allocated objects are allowed, but where heap-allocated objects may not themselves contain pointers. We prove a number of results relating the complexity of verification to the nature of the finite state machine used to specify the property. Some properties are shown to be intractable, but others which appear to be quite similar admit polynomial-time verification algorithms. Our results serve to provide insight into the inherent complexity of important classes of verification problems. In addition, the program abstractions used for the polynomial-time verification algorithms may be of independent interest

Precise Null Pointer Analysis Through Global Value Numbering

Precise analysis of pointer information plays an important role in many static analysis techniques and tools today. The precision, however, must be balanced against the scalability of the analysis. This paper focusses on improving the precision of standard context and flow insensitive alias analysis algorithms at a low scalability cost. In particular, we present a semantics-preserving program transformation that drastically improves the precision of existing analyses when deciding if a pointer can alias NULL. Our program transformation is based on Global Value Numbering, a scheme inspired from compiler optimizations literature. It allows even a flow-insensitive analysis to make use of branch conditions such as checking if a pointer is NULL and gain precision. We perform experiments on real-world code to measure the overhead in performing the transformation and the improvement in the precision of the analysis. We show that the precision improves from 86.56% to 98.05%, while the overhead is insignificant.Comment: 17 pages, 1 section in Appendi

Electrical Behaviour of Polyethylene Vinyl Acetate / ZnO Nanocomposite

Recently, nanoscale materials have attracted material scientists because of their unique size depend-ent magnetic, optical, electrical and thermal properties. Homogeneous dispersion of nanoparticles in the polymer matrix and control of their size are vital to achieve many of these properties. In the present work, Zinc Oxide (ZnO) nanoparticles were prepared by solvothermal route. Chemical replacement reaction was chosen for the homogeneous dispersion of prepared ZnO nanoparticles into polymer matrix. Zinc oxide is an inorganic material with a large direct band gap (3.34 eV), high exciton binding energy (60 meV) and having a unique combination of properties. In inorganic/polymetric composite, the semiconducting nanoclusters enhances the electrical and thermal properties. The dielectric properties of the composites were studied using HIOKI 3532-50 LCR Hitester. The dielectric constant was found to increase with in-creasing the concentration of nano filler. DC electrical conductivity as a function of temperature was stud-ied using Keithley picoammeter 6485. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3563

Cost Reductive Laparoendoscopic Single Site Surgery Endotrainer and Animal Lab Training—Our Methodology

Laparoendoscopic single site surgery (LESS) is a new avenue in laparoscopic urology. The main advantage is the enhanced cosmetic benefits of single hidden scar. Lately many papers are being published on various procedures done by LESS. Like conventional laparoscopy, this approach is likely to be used more widely and hence exposure to this field is essential. However, formal training in this technique is not widely available. Expensive ports and nonavailability of endotrainer may be the factors deterring the training. We have modified the standard laparoscopic endotrainer with improvised ports, to make it suitable for single port laparoscopic training. For the animal lab training improvised ports and low cost instruments were used. Thus the overall cost of the training in LESS was reduced, and better confidence levels were achieved prior to human applications