Network restoration under dual failures using path-protecting preconfigured cycles

This paper presents a design algorithm for networks with a restoration mechanism that provides end-to-end path protection to a set of demands with specified working routes, where demands must survive one or two failures in optical networks and these failures may occur almost instantaneously. Each of the demands protected from two failures is assigned two restoration routes and restoration wavelengths on a cycle. A demand protected from a single failure is assigned one restoration route and restoration wavelengths on a cycle. These assignments are preconfigured so that switching and wavelength conversions are not needed at intermediate nodes of restoration routes. Splitting of demand across multiple restoration routes upon a failure occurrence is not allowed. The algorithm generates a large number of candidate Path-Protecting Preconfigured Cycles (PP-PCs). A candidate cycle may provide protection to a mix of demands requiring different protection levels, where demands may share under certain conditions restoration wavelengths even if they are exposed to common failure scenarios and have overlapping restoration routes. A near-optimal set of preconfigured cycles is selected from among all candidates, attempting to minimize the total cost of restoration wavelengths while ensuring that each demand is assigned to a single preconfigured cycle. This is achieved by solving a set covering problem followed by deleting duplicate demand assignments and by resolving wavelength assignment conflicts.     

Investigating the Intermediate Water Feature of Hydrated Titanium Containing Bioactive Glass

Intermediate water (IW) in hydrated bioactive glasses remains uninvestigated. We obtained titanium (Ti)-containing bioactive glasses (BGTs) (Ti at 5%, 7.5% and 10% of the glass system) using the sol–gel technique. Their thermal, physicochemical, and morphological properties, before and after Ti-doping, were analysed using DTA, XRD, FTIR, TEM, and SEM accessorised with EDAX, and size distribution and zeta potential surface charges were determined using a NanoZetasizer. The IW in hydrated BGTs was investigated by cooling and heating runs of DSC measurements. Moreover, the mode of death in an osteosarcoma cell line (MG63) was evaluated at different times of exposure to BGT discs. Ti doping had no remarkable effect on the thermal, physicochemical, and morphological properties of BGTs. However, the morphology, size, and charges of BGT nano-powders were slightly changed after inclusion of Ti compared with those of BGT0; for example, the particle size increased with increasing Ti content (from 4–5 to 7–28 nm). The IW content was enhanced in the presence of Ti. The mode of cell death revealed the effect of IW content on the proliferation of cells exposed to BGTs. These findings should help improve the biocompatibility of inorganic biomaterials.     

Synchronized manufacturing at final assembly and feeder shops

Many manufacturing environments consist of a final assembly shop that receives components from various feeder shops. Suppose the final assembly shop assembles a mix of products, each requiring varying amounts of different components. Thus, the sequence in which products are assembled imposes time-dependent demands on the feeder shops. Such problems are often found in the assembly of high-tech telecommunications systems and in the assembly of mixed models of automobiles. We develop a variety of models that link the work-in-process inventory in the feeder shop and the finished component inventory to the component production interval and the final assembly sequence. The manufacturing disciplines considered include push, look-ahead and kanban. Feeder shops are assumed to manufacture components continuously, periodically, or at a fixed lot size. Simple performance characteristics of the feeder shop are derived to provide insight into synchronized manufacturing issues and to help evaluate the effect of different final assembly sequences on feeder shops.     

Integrated demand-responsive scheduling of maintenance and transportation operations in military supply chains

The management of a military supply chain (SC) involves the integration of production, packaging, warehousing, repair, maintenance and transportation of army supplies. In this paper, we focus on the integrated demand-responsive scheduling of maintenance and transportation operations within the SC. We consider a modular representation of a SC, in which the maintenance and transportation operations constitute the corresponding modules. An efficient integration of these operations is carried out by an additional controlling (commanding) module. We describe and analyse the optimisation problems arising in each module. The main contribution of the paper is that the analysis and optimisation of the controlling module permit to enhance the performance of the entire SC. Computational experiments prove the validity and effectiveness of the suggested models.     

Message Drop Control Buffer Management Policy for DTN Routing Protocols

In delay tolerant network interruptions will occur continuously because there is no end-to-end path exists for the longer period of time from source to destination. In this context, delays can be immensely large due to its environment contrails e.g. wildlife tracking, sensor network, deep space and ocean networks. Furthermore, larger replication of messages put into the network is to increase delivery probability. Due to this high buffer occupancy storage space and replication result in a huge overhead on the network. Consequently, well-ordered intelligent message control buffer drop policies are necessary to operate on buffer that allows control on messages drop when the node buffers are near to overflow. In this paper, we propose an efficient buffer management policy which is called message drop control source relay (MDC-SR) for delay tolerant routing protocols. We also illustrate that conventional buffer management policy like Drop oldest, LIFO and MOFO be ineffective to consider all appropriate information in this framework. The proposed MDC-SR buffer policy controls the message drop while at the same time maximizes the delivery probability and buffer time average and reduces the message relay, drop and hop count in the reasonable amount. Using simulations support on an imitation mobility models Shortest Path Map Based Movement and Map Route Movements, we show that our drop buffer management MDC-SR with random message sizes performs better as compared to existing MOFO, LIFO and DOA.     

Characterization of LDPE and LDPE/EVA blends crosslinked by electron beam irradiation and foamed with chemical foaming agent

In this work, low density polyethylene and its blend with poly (ethylene vinyl acetate) (LDPE/EVA) (80/20) were mixed with different concentration of Azodicarbonamide (ACA) as a foaming agent. The specimens were crosslinked by electron beam irradiation in presence of 1,6-Hexandiol diacrylate (HDDA). The foam structure was obtained by heating the crosslinked sheets at 225 °C. The effect of ACA content and irradiation dose on the gel percent, tensile strength, cell density, and thermal stabilities was investigated. The results showed clearly that the increasing of ACA content reduces the stress and strain at break and increase the gel content. On the other hand, the foaming degree increases with increasing the ACA content and decreases with increasing irradiation dose.