Performance evaluation of an efficient reduced-complexity time synchronization approach for OFDM systems

This paper presents a performance analysis of a recently proposed preamble-based reduced-complexity (RC) two-stage synchronization technique. The preamble, composed of two identical subsequences, is first used to determine an uncertainty interval based on Cox and Schmidl algorithm. Then, a differential correlation-based metric is carried using a new sequence obtained by element wise multiplication of the preamble subsequence and a shifted version of it. This second step is performed to fine tune the coarse time estimate, by carrying the differential correlation-based metric over the uncertainty interval of limited width around the coarse estimate, thus leading to low computational load. In this paper, we first discuss some complexity issues of the RC approach compared to previously proposed algorithms. Then, we study the effect of the training sequence class and length choices on the synchronization performance in the case of multipath channels. The impact of the uncertainty interval width on the trade-off between performance and complexity is also studied. The two-stage approach was found to provide almost equal performance to those obtained by the most efficient differential correlation-based benchmarks. However, it has a very reduced computational load, equivalent to that of sliding correlation-based approaches.     

An Analysis of Intermetallic Bonding between a Ring Carrier and an Aluminum Piston Alloy

This paper presents the results of an analysis of the formation of an intermetallic bond between a ring carrier and an aluminum piston alloy. The ring carrier is made of austenitic cast iron (Ni-Resist) to increase the wear resistance of the first ring groove and is applied in highly loaded diesel engines. The most important thing is that the Ni-Resist (ferrous) must be bonded with a non-ferrous piston material during the casting of the piston. A metallographic investigation using an optical microscope in combination with the SEM/EDS analysis of the quality of the intermetallic bonding layer was done. The test results show that if the proper conditions are met, then the preparation of the ring carrier can be made successfully, as can the formation of the metal connection between the two materials of different qualities.     

Investigating the Blusa: The Cultural and Sartorial Biography of an Algerian Dress

This essay describes the evolution of the garment known as a blusa, worn by urban women in north-western Algeria. The blusa, a full-length dress with short sleeves, was conceived and developed in the cities of Tlemcen and Oran. It incorporates locally meaningful traditions as well as fashion styles in conjunction with different cultures. Its transformation illustrates how Algerian women resisted cultural assimilation through dress while creatively appropriating western European textiles, techniques and aesthetics in their clothing, during the French colonial period (1830–1962) and its aftermath. The exploration of the contemporary blusa variations reveals how the relationship between clothing and identity is still highly complex in Algerian cities. To date, the invention, the rituals, the design, and the production of the blusa dress has been little studied. This paper reconstitutes an historical puzzle based on recent object-based research and anthropological investigations. It seeks to interpret the blusa as an interface between tradition and modernity.     

Steam reforming of methanol over ruthenium impregnated ceria,alumina and ceria–alumina catalysts

The wet impregnation method was used to prepare different ruthenium promoted Ce–Al catalysts. These catalysts were used in the steam reforming of methanol reaction (SRM). The effects of the reaction temperature (200–400 C) and the catalyst composition were studied for optimization reasons. The steam to methanol molar ratio was kept constant (S/M = 2). The promotion of cerium/aluminum oxides with Ru enhanced their catalytic activity. The catalytic test results showed that the Ru/Ce combination was the most beneficial. The synergy between Ru and cerium oxide led to the formation of active sites with excellent redox properties. For high active phase content, the 5 RuCe catalyst exhibited the highest hydrogen production amount with no CO formation. This catalyst was kept under stream for 5 days at 400 C, and no significant deactivation was observed. Copyright © 2016 John Wiley & Sons, Ltd.     

Improving the Quality of Mobile Learning Services

Wireless Personal Communications - The quality of services (QoS) has a key role to improve the performances of the collaborative mobile learning. However, many factors can limit it such as the...     

The release rate and antimicrobial activity of calcium-alginate films containing self-microemulsifying Thymus vulgaris essential oil against Escherichia coli and Staphylococcus aureus

The aim of this study was to fabricate antimicrobial calcium-alginate-based films containing the self-microemulsifying thyme essential oil (TEO) formulations using Tween 80 as the surfactant, and acetic (AA) or propionic (PA) acids as the cosurfactants. A Ca-alginate film containing nano-emulsified TEO as well as a neat Ca-alginate film were considered as the controls. The scanning electron microscopy micrographs showed a highly porous texture for SME films, which resulted in an increase in water vapor permeability and water absorption capacity of these films. The SME films released the TEO completely within 155 min and inhibited the growth of S. aureus and E. coli in in vitro antimicrobial tests. The population of S. aureus and E. coli reduced significantly in ground beef covered with SME films. The results of this study showed that self-microemulsifying TEO films could effectively increase the shelf life of ground beef by controlling its microbial population.     

Implicit Decals: Interactive Editing of Repetitive Patterns on Surfaces

Texture mapping is an essential component for creating 3D models and is widely used in both the game and the movie industries. Creating texture maps has always been a complex task and existing methods carefully balance flexibility with ease of use. One difficulty in using texturing is the repeated placement of individual textures over larger areas. In this paper, we propose a method which uses decals to place images onto a model. Our method allows the decals to compete for space and to deform as they are being pushed by other decals. A spherical field function is used to determine the position and the size of each decal and the deformation applied to fit the decals. The decals may span multiple objects with heterogeneous representations. Our method does not require an explicit parametrization of the model. As such, varieties of patterns, including repeated patterns like rocks, tiles and scales can be mapped. We have implemented the method using the GPU where placement, size and orientation of thousands of decals are manipulated in real time.     

Non‐minimum phase switched systems: HOSM‐based fault detection and fault identification via Volterra integral equation

In this paper, the problem of continuous and discrete state estimation for a class of linear switched systems with additive faults is studied. The class of systems under study can contain non‐minimum phase zeroes in some of their ‘operating modes’. The conditions for exact reconstruction of the discrete state are given using structural properties of the switched system. The state space is decomposed into the strongly observable part, the non‐strongly observable part, and the unobservable part, to analyze the effect of the unknown inputs. State observers based on high‐order sliding mode to exactly estimate the strongly observable part and Luenberger‐like observers to estimate the remaining parts are proposed. For the case when the exact estimation of the state cannot be achieved, the ultimate bounds on the estimation errors are provided. The proposed strategy includes a high‐order sliding‐mode‐based fault detection and a fault identification scheme via the solution of a Volterra integral equation. The feasibility of the proposed method is illustrated by simulations. Copyright © 2013 John Wiley & Sons, Ltd.     

The landing gear case study: challenges and experiments

International Journal on Software Tools for Technology Transfer -