Sharing Memory between Byzantine Processes Using Policy-Enforced Tuple Spaces

Despite the large amount of Byzantine fault-tolerant algorithms for message-passing systems designed through the years, only recently algorithms for the coordination of processes subject to Byzantine failures using shared memory have appeared. This paper presents a new computing model in which shared memory objects are protected by fine-grained access policies, and a new shared memory object, the Policy-Enforced Augmented Tuple Space (PEATS). We show the benefits of this model by providing simple and efficient consensus algorithms. These algorithms are much simpler and requires less shared memory operations, using also less memory bits than previous algorithms based on ACLs and sticky bits. We also prove that PEATS objects are universal, i.e., that they can be used to implement any other shared memory object, and present lock-free and wait-free universal constructions.     

Predicting the performance of reconfigurable optical interconnects in distributed shared-memory systems

New advances in reconfigurable optical interconnect technologies will allow the fabrication of low-cost, fast and run-time adaptable networks for connecting processors and memory modules in large distributed shared-memory multiprocessor machines. Since the switching times of these components are typically high compared to the memory access time, reconfiguration exploits low frequency dynamics in the network traffic patterns. These are however not easily reproduced using statistical traffic generation, a tool commonly used when doing a fast design space exploration. In this paper, we present a technique that can predict network performance, based on the traffic patterns obtained from simulating the execution of real benchmark applications, but without the need to perform these slow full-system simulations for every parameter set of interest. This again allows for a quick comparison of different network implementations with good relative accuracy, narrowing down the design space for more detailed examination.     

Hybrid digital-analog technique for UWB direction finding

In this letter, we propose an alternative approach for UWB direction finding using hybrid digital-analog technique. The proposed system uses an array of leading-edge pulse detection scheme in analog domain. The detection scheme is realized using tunnel diode with envelope detector and comparator latch, whose output is digital binary signal. The outputs or all array branches are then summed up to form a staircase-shaped waveform, whereby the slope of the waveform indicates the direction of impinging UWB signal. In order to detect the slope and produce the estimation of the direction, an analog differentiator joint with a peak detector is utilized. The proposed system is relatively simple and does not require high sampling rate or high speed DAC.     

Regulation of Anti-Apoptotic SOD2 and BIRC3 in Periodontal Cells and Tissues

The aim of the study was to clarify whether orthodontic forces and periodontitis interact with respect to the anti-apoptotic molecules superoxide dismutase 2 (SOD2) and baculoviral IAP repeat-containing protein 3 (BIRC3). SOD2, BIRC3, and the apoptotic markers caspases 3 (CASP3) and 9 (CASP9) were analyzed in gingiva from periodontally healthy and periodontitis subjects by real-time PCR and immunohistochemistry. SOD2 and BIRC3 were also studied in gingiva from rats with experimental periodontitis and/or orthodontic tooth movement. Additionally, SOD2 and BIRC3 levels were examined in human periodontal fibroblasts incubated with Fusobacterium nucleatum and/or subjected to mechanical forces. Gingiva from periodontitis patients showed significantly higher SOD2, BIRC3, CASP3, and CASP9 levels than periodontally healthy gingiva. SOD2 and BIRC3 expressions were also significantly increased in the gingiva from rats with experimental periodontitis, but the upregulation of both molecules was significantly diminished in the concomitant presence of orthodontic tooth movement. In vitro, SOD2 and BIRC3 levels were significantly increased by F. nucleatum, but this stimulatory effect was also significantly inhibited by mechanical forces. Our study suggests that SOD2 and BIRC3 are produced in periodontal infection as a protective mechanism against exaggerated apoptosis. In the concomitant presence of orthodontic forces, this protective anti-apoptotic mechanism may get lost.     

Bioactive albumin functionalized polylactic acid membranes for improved biocompatibility

Biocompatibility is a major challenge for successful application of many biomaterials. In this study the ability to coat chemically and enzymatically activated poly(L-lactic acid) (PLA) membranes with heat denatured human serum albumin to improve biocompatibility was investigated. PLA membranes hydrolyzed with NaOH or cutinase and then treated with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, hydrochloride (EDAC) as a heterobifunctional cross-linker promoted the coupling COOH groups on PLA membranes and NH₂ groups of heat denatured human serum albumin. This resulted in increased hydrophilicity (lowest water contact angles of 43° and 35°) and highest antioxidant activity (quenching of 79 μM and 115 μM tetramethylazobisquinone (TMAMQ) for NaOH and cutinase pretreated membranes, respectively). FTIR analysis of modified PLA membranes showed new peaks attributed to human serum albumin (amide bond, NH₂ and side chain stretching) appearing within 3600–3000 cm^?1 and 1700–1500 cm^?1 (Fig. 3). MTT studies also showed that osteoblasts-like and MC-3T3-E1 cells viability increased 2.4 times as compared to untreated PLA membranes. The study therefore shows that this strategy of modifying the surfaces of PLA polymers could significantly improve biocompatibility.     

An inventory model involving back-order price discount when the amount received is uncertain

This paper presents and analyses the continuous review inventory model with order quantity, safety factor, back-order price discount, ordering cost and lead time as decision variables. Our work is based on the paper of Huang (2010 Huang, S.-P. (2010). Using simple and efficient algorithm involving ordering cost reduction and backorder price discount on inventory system under variable lead time. Information Technology Journal, 9(4), 804–810.[Crossref] , [Google Scholar]). We extend the model to incorporate the situation when the amount received is uncertain. The lead time demand is assumed follows a normal distribution. A solution procedure is developed to find the optimal solution. A numerical example is given to illustrate the model. A sensitivity analysis is also included to describe the effects of changes in the model parameters on the expected annual cost.     

Load–displacement behavior of glass fiber/epoxy composite plates with circular cut-outs subjected to compressive load

An experimental study of the behavior of woven glass fiber/epoxy composite laminated panels under compression is presented. Compression tests were performed on to 16 fiber-glass laminated plates with and without circular cut-outs using the compressed machine. The maximum load of failure for each of the glass-fiber/epoxy laminated plates under compression has been determined experimentally. A parametric study was performed as well to investigate the effects of varying the centrally located circular cut-out sizes and fiber angle-ply orientations on to the ultimate load. The experimental work revealed that as the cut-out size increases, the maximum load of the composite plate decreases. Also, it has been observed that cross-ply laminates possess the greatest ultimate load as compared to other types of ply stacking sequences and orientations.     

Pore structure alteration of porous carbon by catalytic coke deposition

The feasibility of preparing Carbon Molecular Sieve (CMS) by tailoring pore structure of activated carbon under catalytic cracking of benzene has been examined. In this method, benzene vapour was cracked over metal-impregnated activated carbon particles at 523–773 K. Among the metal catalysts tested, only cobalt exhibited significant cracking activity toward benzene. In this range of temperature coke was originated on the metal surface only, therefore an excessive coke deposition as indicated in non-catalytic process was not observed. The amount of coke and the site of deposition in the pore network were determined to some extent by the metal loading as well as the rate of benzene cracking. Raman spectra indicated that the coke produced was less amorphous than those produced in non-catalytic processes. Only a small loss in micropore volume and surface area was observed after the coke deposition process. The CMS produced was tested for its adsorption characteristics of carbon dioxide and methane. The improvement in the CO₂/CH₄ kinetic selectivity was observed.