From Syntactic Theories to Interpreters: Automating the Proof of Unique Decomposition

Developing syntactic theories for reasoning about programming languages usually involves proving a unique-decomposition lemma. The proof of such a lemma is tedious, error-prone, and is usually attempted many times during the design of a theory. We therefore investigate the automation of such proofs.We map the unique-decomposition lemma to the problems of checking equivalence and ambiguity of syntactic definitions. Because checking these properties of context-free grammars is undecidable, we work with regular tree grammars and use algorithms on finite tree automata to perform the checking. To make up for the insufficient expressiveness of regular tree grammars, we extend the basic framework with built-in types and constants, contexts, and polymorphic types.Our implementation extends an earlier system by Xiao et al. [16] that translates semantic specifications expressed as syntactic theories to interpreters. We have successfully used the combined system to generate interpreters and verify the unique-decomposition lemma for a number of examples.     

蒸汽系统节能设计

在化工生产过程中,蒸汽系统的节能是企业节约运营成本的方法之一。文章分析了生产企业在使用蒸汽过程当中主要存在的问题,并概括介绍了蒸汽系统的各个环节该如何进行节能设计,从多方面入手,提高生产企业蒸汽系统的能源效率。     

A type-theoretic foundation of delimited continuations

There is a correspondence between classical logic and programming language calculi with first-class continuations. With the addition of control delimiters, the continuations become composable and the calculi become more expressive. We present a fine-grained analysis of control delimiters and formalise that their addition corresponds to the addition of a single dynamically-scoped variable modelling the special top-level continuation. From a type perspective, the dynamically-scoped variable requires effect annotations. In the presence of control, the dynamically-scoped variable can be interpreted in a purely functional way by applying a store-passing style. At the type level, the effect annotations are mapped within standard classical logic extended with the dual of implication, namely subtraction. A continuation-passing-style transformation of lambda-calculus with control and subtraction is defined. Combining the translations provides a decomposition of standard CPS transformations for delimited continuations. Incidentally, we also give a direct normalisation proof of the simply-typed lambda-calculus with control and subtraction.     

Recognition of Handwritten Arabic Characters using Histograms of Oriented Gradient (HOG)

Optical Character Recognition (OCR) is the process of recognizing printed or handwritten text on paper documents. This paper proposes an OCR system for Arabic characters. In addition to the preprocessing phase, the proposed recognition system consists mainly of three phases. In the first phase, we employ word segmentation to extract characters. In the second phase, Histograms of Oriented Gradient (HOG) are used for feature extraction. The final phase employs Support Vector Machine (SVM) for classifying characters. We have applied the proposed method for the recognition of Jordanian city, town, and village names as a case study, in addition to many other words that offers the characters shapes that are not covered with Jordan cites. The set has carefully been selected to include every Arabic character in its all four forms. To this end, we have built our own dataset consisting of more than 43.000 handwritten Arabic words (30000 used in the training stage and 13000 used in the testing stage). Experimental results showed a great success of our recognition method compared to the state of the art techniques, where we could achieve very high recognition rates exceeding 99%.     

Improving mobile multi-tap text entry for Arabic language

Classical mobile phone keypads which consist of 12 buttons are commonly used to write short text messages through two common methods, the multi-tap and the predictive text entry. For the Arabic language mobile keypads, all Arabic letters are distributed over the 8 buttons of the keypad where three or more letters share the same button. In this paper, a new text entry environment is proposed. The environment includes two proposed improved approaches for Arabic language messages to make the multi-tap text entry method faster and easier. The first approach is based on the idea of remapping the distribution of Arabic letters on the keypad according to the frequency of letters. In the second approach, a bi-Gram based method is used to predict the next letter to be typed automatically. The proposed approaches are evaluated using a corpus of 1514 real Arabic text messages. Several experiments were conducted to evaluate the proposed text entry environment. The results of the experiments have showed that using the proposed remapped keypad is faster and consumes less effort in comparison to the classical keypad.     

海量存储系统可用性静态测试评估方案

本文分析和研究了海量存储系统可用性关键技术和体系结构,设计制定可用性静态测试评估方案,方案分为定性检查和准则评估两个部分。通过可用性静态测试评估,可以对目标系统的可用性做出直观和准确的初步评价。     

A Learning Based Brain Tumor Detection System

Brain tumor is one of the most dangerous disease that causes due to uncontrollable and abnormal cell partition. In this paper, we have used MRI brain scan in comparison with CT brain scan as it is less harmful to detect brain tumor. We considered watershed segmentation technique for brain tumor detection. The proposed methodology is divided as follows: pre-processing, computing foreground applying watershed, extract and supply features to machine learning algorithms. Consequently, this study is tested on big data set of images and we achieved acceptable accuracy from K-NN classification algorithm in detection of brain tumor.     

Osseointegration evaluation of laser-deposited titanium dioxide nanoparticles on commercially pure titanium dental implants

The nanotechnology field plays an important role in the improvement of dental implant surfaces. However, the different techniques used to coat these implants with nanostructured materials can differently affect cells, biomolecules and even ions at the nano scale level. The aim of this study is to evaluate and compare the structural, biomechanical and histological characterization of nano titania films produced by either modified laser or dip coating techniques on commercially pure titanium implant fixtures. Grade II commercially pure titanium rectangular samples measuring 35?×?12?×?0.25?mm length, width and thickness, respectively were coated with titania films using a modified laser deposition technique as the experimental group, while the control group was dip-coated with titania film. The crystallinity, surface roughness, histological feature, microstructures and removal torque values were investigated and compared between the groups. Compared with dip coating technique, the modified laser technique provided a higher quality thin coating film, with improved surface roughness values. For in vivo examinations, forty coated screw-designed dental implants were inserted into the tibia of 20 white New Zealand rabbits’ bone. Biomechanical and histological evaluations were performed after 2 and 4 weeks of implantation. The histological findings showed a variation in the bone response around coated implants done with different coating techniques and different healing intervals. Modified laser-coated samples revealed a significant improvement in structure, surface roughness values, bone integration and bond strength at the bone-implant interface than dip-coated samples. Thus, this technique can be an alternative for coating titanium dental implants.     

Boosted PTS Method with Mu-Law Companding Techniques for PAPR Reduction in OFDM Systems

Wireless Personal Communications - This paper proposes an enhanced PAPR reduction technique which combines an enhanced PTS method with Mu-Law companding. The enhanced PTS method improves...