Design and analysis of an integrated checkpointing and recoveryscheme for distributed applications

An integrated checkpointing and recovery scheme which exploits the low latency and high coverage characteristics of a concurrent error detection scheme is presented. Message dependency, which is the main source of multistep rollback in distributed systems, is minimized by using a new message validation technique derived from the notion of concurrent error detection. The concept of a new global state matrix is introduced to track error checking and message dependency in a distributed system and assist in the recovery. The analytical model, algorithms and data structures to support an easy implementation of the new scheme are presented. The completeness and correctness of the algorithms are proved. A number of scenarios and illustrations that give the details of the analytical model are presented. The benefits of the integrated checkpointing scheme are quantified by means of simulation using an object-oriented test framework     

Models for strength prediction of foam concrete

There are several strength prediction relations developed for plain cement paste, mortar and concrete. In concrete where air voids contribute significantly to volume of voids (like aerated and foam concrete), more general expressions including the volume of air voids is to be developed as the better alternative. The objective of this paper is to propose prediction relations for the compressive strength of foam concrete by extending two of the well-known relations available for cement paste, mortar and normal concrete, viz., Balshin’s strength-porosity model and Power’s gel-space ratio equation. For this, theoretical equations were derived for porosity and gel-space ratio relating it to the density, proportion of ingredients in the mix and material characteristics like specific gravity. Foam concrete with fly ash showed lesser dependency on pore parameters than cement-sand mixes. As both the prediction relations developed in this study consider the effect of composition on the strength, it can serve as a simple tool for predicting the strength of foam concrete. But strength-porosity model stands out compared to gel-space model as it correlates well with the measured strength and also because of its ease in application since it employs the composition of constituents and easily measurable parameters.     

Nonisothermal thermophysical evaluation of a polypropylene + ethylene propylene diene (EPDM) blend

Recent theoretical evidence indicates that the rate effects of quenching seen in the isothermal crystallization kinetics can be eliminated through use of a nonisothermal method based on constant rate heating and cooling through inclusion of an activation energy. To investigate the potential of this method for polymers, we apply it to semicrystalline polymers: polypropylene (PP), a binary blend PP + ethylene propylene diene rubber (EPDM) and a ternary system PP + EPDM + high-density polyethylene (PE). As opposed to traditional rubber-modified systems such as high-impact polystyrene (HIPS) wherein an amorphous component is blended with a rubbery one, the PP + EPDM system has a semicrystalline component. From the perspective of crystal lamellae growth or stress induced slip, the thermophysical properties are also a concern. Therefore, we use differential scanning calorimetry (DSC) and thermomechanical analysis (TMA). The results indicate that differences between isothermal and nonisothermal conditions must be taken into account since the latter conditions prevail in extrusion, injection molding, and in hot coating-slow cooling processes. Our nonisothermal analysis of crystallization should assist in the optimization of cooling of semicrystalline polymers.     

Exploring High‐Dimensional Structure via Axis‐Aligned Decomposition of Linear Projections

Two‐dimensional embeddings remain the dominant approach to visualize high dimensional data. The choice of embeddings ranges from highly non‐linear ones, which can capture complex relationships but are difficult to interpret quantitatively, to axis‐aligned projections, which are easy to interpret but are limited to bivariate relationships. Linear project can be considered as a compromise between complexity and interpretability, as they allow explicit axes labels, yet provide significantly more degrees of freedom compared to axis‐aligned projections. Nevertheless, interpreting the axes directions, which are often linear combinations of many non‐trivial components, remains difficult. To address this problem we introduce a structure aware decomposition of (multiple) linear projections into sparse sets of axis‐aligned projections, which jointly capture all information of the original linear ones. In particular, we use tools from Dempster‐Shafer theory to formally define how relevant a given axis‐aligned project is to explain the neighborhood relations displayed in some linear projection. Furthermore, we introduce a new approach to discover a diverse set of high quality linear projections and show that in practice the information of k linear projections is often jointly encoded in ～ k axis‐aligned plots. We have integrated these ideas into an interactive visualization system that allows users to jointly browse both linear projections and their axis‐aligned representatives. Using a number of case studies we show how the resulting plots lead to more intuitive visualizations and new insights.     

Rationalized method to enhance the chromium uptake in tanning process: role of Gallic acid

In the present study, a greener approach to tanning process based on Gallic acid (GA: Trihydroxybenzoic acid) assisted chrome tanning has been attempted. The exhaustion, the thermal stability, mechanical strength and organoleptic properties of tanned leather as well as the evaluation of eco-friendly characteristics were investigated. The microshrinkage, differential scanning calorimetric and thermo mechanical analyses show the shrinkage temperature, denaturation temperature and % elongation, respectively, of GA-chrome-tanned leather are more than that of chrome alone. Chrome exhaustion greater than 93 % has been achieved. This high exhaust aid offers fullness and softness to leather compared to chrome alone. The environmental impact assessment reveals that the developed high exhaust chrome tanning process is beneficial as significant reduction in total solids content (TSC) such as dissolved solids and suspended solids in the effluent is achieved when compared to tanning with chrome alone. The GA could bring about the enhancement of chromium(III) uptake, significant reduction in TSC resulting in improved environmental, economic and social positive impact.     

Dynamic wavelength and bandwidth allocation for supporting diverse customers and prioritized traffic in NG-PON2 networks

Photonic Network Communications - Resource allocation is a fundamental task in any PON and it is necessary to have an efficient scheme that reduces delay, maximizes bandwidth usage, and minimizes...     

A geo-engineering classification for rocks and rock masses

In this article, an attempt is made to assess the reliability of predicting the uniaxial compressive strength and the corresponding modulus of a rock mass by current approaches. These two basic engineering properties, when estimated from rock mass rating (RMR), Q and geological strength index (GSI), indicate hardly any change in the modulus ratio with the change in the quality of the rock mass from very good to very poor. However, the modulus ratio obtained from the relations involving the joint factor, J_f, indicate a definite decrease in the modulus ratio with a decrease in the quality of the rock mass. The strength and modulus in the unconfined and confined states, the modulus ratio and failure strain in the unconfined case were linked to J_f in earlier publications based on a large experimental database. Some of these relations were adopted to verify the response of jointed test specimens, the response of the rock mass during excavations for mining and civil underground chambers, in establishing ground reaction curves including the extent of the broken zone, and the bearing capacity of shallow foundations.The joint factor is now linked to RMR, Q and GSI. The prediction of compressive strength and modulus of the rock mass appears to be more suitable. For classifying the rock, based on these properties, the Deere and Miller engineering classification, applicable to intact rocks, has been suitably modified and adopted. The results of different modes of failure of jointed specimens establish definite trends of changes in the modulus ratio originating from the intact rock value on the modified Deere and Miller plot. A geo-engineering classification is evolved by considering strength, modulus, quantifiable weathering index and lithological aspects of the rock.     

A dynamic local method for bandwidth adaptation in bundle links to conserve energy in core networks

In this paper, we propose two distributed local-optimized algorithms (FLHT and DLHT), which can dynamically adjust the number of active sublinks, to save power consumption in the core network for both bin packing and load-balancing cases. A series of experiments were conducted on an Internet2 based synthetic network for both cases. The experiment results show that our FLHT and DLHT algorithms can achieve high energy savings without substantial data loss.     

Historicizing New Media: A Content Analysis of Twitter

This paper seeks to historicize Twitter within a longer historical framework of diaries to better understand Twitter and broader communication practices and patterns. Based on a review of historical literature regarding 18th and 19th century diaries, we created a content analysis coding scheme to analyze a random sample of publicly available Twitter messages according to themes in the diaries. Findings suggest commentary and accounting styles are the most popular narrative styles on Twitter. Despite important differences between the historical diaries and Twitter, this analysis reveals long‐standing social needs to account, reflect, communicate, and share with others using media of the times.