Starvation and critical race analyzers for Ada

Starvation and critical race analysis tools for Ada designs are described. These tools are part of a temporal analysis toolset that includes an operational specification language, a language interpreter, and a deadlock analyzer for Ada. The starvation analyzer is based on a set-theoretic model of starvation. It uses a proof tree produced by the deadlock analyzer to define the possible computation space of the design. A preprocessing phase of the starvation tool optimizes the analysis so that the resulting analysis is efficient. Unlike livelock analysis in state machines, the starvation analyzer does not require a priori specification of home states to discern liveness. The critical race analysis tool provides semiautomatic proof of critical races by identifying nondeterministic rendezvous (races) from the proof tree generated by the deadlock analyzer, and then assisting the human operator in identifying which of these constitute critical races. Several design examples are used to demonstrate the capabilities of the two analysis methods     

Passive cooling techniques through reflective and radiative roofs in tropical houses in Southeast Asia: A literture review

Cooling is one of the major concerns in building tropical houses. This problem is exacerbated by the heat gain of the roof, which constitutes 70% of the total heat gain. The passive cooling technique is one of the innovative practices and technologies that provide buildings with comfortable conditions through natural means. Reflective and radiative processes are the methods used to decrease heat gain by facilitating the elimination of excess heat in a building's interior to maintain a comfortable environment. Given that the potential of these techniques vary from region to region, their application in the tropics should be examined. Exploring these approaches in detail allows us to rethink how to effectively adapt these techniques to overcome the build-up of heat in modern tropical houses in Southeast Asia. This study reviews the physical characteristics of these approaches to guide architects and building designers. Results indicate a great reduction in operational cost. However, the significant differences in the performance of colour and material properties should be considered, given that the selected approach strongly affects the required thermal conditions of a building.     

Investigation of Charge Transport in Percolating Network of PdCu Nanoclusters

Transport of charge carriers in percolating nanocluster devices based on bimetallic PdCu nanoclusters was investigated in this work.The device was fabricated by self-assembly of the nanoclusters between electrical electrodes inside an ultra-high vacuum compatible system.The average size of the produced nanoclusters was 7.3 nm,and the composition was Pd_0.77Cu_0.23.Systematic in situ current-voltage measurements as a function of temperature were performed which provide a conductance-temperature profile.The results are explained in terms of the charge carriers’ tunneling through small potential barriers at the junctions between nanoclusters.The results predict the size of the nanoclusters as well as the magnitude of the potential difference of the tunneling barriers.This investigation helps understanding the nature of the interface between the nanoclusters and the charge carrier transport within those devices to be utilized for optimizing gas sensing properties of PdCu nanocluster devices.     

A comparative study between unvented and vented attics powered by the hybrid turbine ventilator in Malaysian houses

Vented attic is a design technique that provides a better solution to reduce solar heat gains trapped in a roof attic. However, its application in the tropical climate is very rare if not, ignored, especially in Malaysian houses. This paper seeks to identify, and compare the performance of attic ventilation by a single hybrid turbine ventilator for a specific volume under both unvented and vented conditions. The study was done in an actual roof attic (10 m³) located in Universiti Sains Malaysia. The results indicate that the reduction of the attic air temperature was 6.4°C, while stabilising the level of relative humidity to about 40–50% which is higher than that for an unvented attic by 10%. Furthermore, the findings reveal that by incorporating a 50 W poly-crystalline solar panel with a turbine ventilator of Ø 45 cm, the peak value of the attic air velocity had exceeded 1.3 m/s when the solar radiation was observed to be around 800 W/m².     

Impact of die wear and punch surface textures on aluminium can wall

Aluminium can manufacturing uses a wide range of punch sleeve surface roughness and textures. The ironing die and the punch tooling both can vary in the roughness from 0.04 μm to 0.4 μm Ra during the can forming process. This, together with the roughness of the incoming can body sheet (from 0.3 μm to 0.6 μm Ra) creates a wide range of tool/metal interface coefficients of friction. Ironing dies become rougher and have to be replaced frequently once they lose their shape. Punches maintain a consistent roughness for periods of a week to a month and any surface wear is compensated for with die changes. The initial die and punch surface finish adopted by a manufacturing unit determines the long time plant productivity and punch life. A higher friction on the punch side, compared to the die side, is the preferred manufacturing operating condition. Departures from the preferred condition with ground, polished, cross-hatch and media textured punches are examined. Plants that prefer polished carbide punches over cross-hatched must have their lubrication and coolant parameters controlled within a very narrow operating window. A larger operating window and better performance is achieved with the cross-hatch and micro-textured punches having a Ra less than half that of the can body sheet. Above all, a random isotropic texture is identified as the ideal punch sleeve surface texture and the best performer for aluminium can manufacture.     

Long-Term Vitamin D Deficiency Results in the Inhibition of Cell Proliferation and Alteration of Multiple Gastric Epithelial Cell Lineages in Mice

Over one billion people globally are vitamin D (VD) deficient. Studies on the biological roles of VD are numerous but very little on the stomach. This project aims to understand how gastric homeostasis is affected by VD deficiency caused by prolonged exposure to darkness alone or combined with VD deficient diet. Three groups of C57/BL6 mice were subjected to different light exposure conditions and diets for 12 months (n = 8–12/group): control—12 h/12 h light/dark SDL (Standard Diet/Light), 24 h dark SDD (Standard Diet/Dark), and 24 h dark VDD (VD deficient diet/Dark). Stomach samples were collected for different multi-label lectin-/immuno-histochemical and qRT-PCR analyses, and the serum for LC-MS-MS. We found that the membrane VD receptor is expressed widely in the stomach when compared to nuclear VD receptors. Compared to SDL, VDD mice developed mucous cell expansion with increased mucins-mRNA (3.27 ± 2.73 (p < 0.05)) increased apoptotic cells, 15 ± 7 (p ≤ 0.001)); decreased cell proliferation, 4 ± 4 (p < 0.05)) and decreased acid secretion 33 ± 2 μEq/kg (p ≤ 0.0001)). Interestingly, mice exposed to full darkness developed mild VD deficiency with higher VD epimer levels: 11.9 ± 2.08 ng/mL (p ≤ 0.0001)), expansion in zymogenic cell number (16 ± 3 (p ≤ 0.01)), and a reduction in acid secretion (18 ± 2 μEq/kg (p ≤ 0.0001)). In conclusion, changes in light exposure or VD levels have serious physiological effects on the gastric mucosa, which should be considered during the management of gastric disorders.     

Adaptive image coding with perceptual distortion control

This paper presents a discrete cosine transform (DCT)-based locally adaptive perceptual image coder, which discriminates between image components based on their perceptual relevance for achieving increased performance in terms of quality and bit rate. The new coder uses a locally adaptive perceptual quantization scheme based on a tractable perceptual distortion metric. Our strategy is to exploit human visual masking properties by deriving visual masking thresholds in a locally adaptive fashion. The derived masking thresholds are used in controlling the quantization stage by adapting the quantizer reconstruction levels in order to meet the desired target perceptual distortion. The proposed coding scheme is flexible in that it can be easily extended to work with any subband-based decomposition in addition to block-based transform methods. Compared to existing perceptual coding methods, the proposed perceptual coding method exhibits superior performance in terms of bit rate and distortion control. Coding results are presented to illustrate the performance of the presented coding scheme.     

Sensorless Reaction Force Estimation of the End Effector of a Dual-arm Robot Manipulator Using Sliding Mode Control with a Sliding Perturbation Observer

International Journal of Control, Automation and Systems - We estimated the reaction force for assembly work with a three-link dual-arm robot manipulator using sliding mode control with a sliding...     

On stable equal-order finite element formulations for incompressible flow problems

In this work we discuss stable equal-order finite element formulations for incompressible flow problems based on Petrov–Galerkin methods, constructed by adding to the classical Galerkin formulation least-squares of the governing equations. Continuous and discontinuous pressure interpolations are considered. Numerical results are presented reinforcing the numerical analysis.