Pre‐handover signalling for QoS aware mobility management

In this paper we present a new approach to provide fast handover in Mobile IP. A new Pre‐Handover Signalling (PHS) protocol is proposed to allow the network to achieve accurate handover decisions considering different constraints such as QoS, load balancing in the base stations, the user profile, the mobile node service requirements, etc. In addition we propose to minimize the time discovery of the new base station in order to minimize the handover latency. We propose to start the PHS as soon as the mobile node crosses a predefined critical zone area in its current location, this signalling will provide a list of candidate cells to the mobile node with corresponding priorities; the mobile node will select the highest priority base station as soon as the layer two handover occurs. We propose in the current work to use an extension of COPS (Common Open Policy Service) to support the proposed PHS mechanism and overcome the blind handover decisions of Mobile IP and improve the handover performance. Copyright © 2004 John Wiley & Sons, Ltd.     

Study of Foaming Properties and Effect of the Isomeric Distribution of Some Anionic Surfactants

Using different reaction conditions of photosulfochlorination of n-dodecane, two samples of anionic surfactants of sulfonate type are obtained. Their micellar behavior has been already reported and the relationship between their isomeric distribution and their chemical structures and micellar behaviors have been more thoroughly explored. In this investigation, we screened the foaming properties (foaming power and foam stability) by a standardized method very similar to the Ross–Miles foaming tests to identify which surfactants are suitable for applications requiring high foaming, or, alternatively, low foaming. The results obtained for the synthesized surfactants are compared to those obtained for an industrial sample of secondary alkanesulfonate (Hostapur 60) and to those of a commercial sample of sodium dodecylsulfate used as reference for anionic surfactants. The foam formation and foam stability of aqueous solutions of the two samples of dodecanesulfonate are compared as a function of their isomeric distribution. These compounds show good foaming power characterized in most cases by metastable or dry foams. The highest foaming power is obtained for the sample rich in primary isomers which also produces foam with a relatively high stability. For the sample rich in secondary isomers we observe under fixed conditions a comparable initial foam height but the foam stability turns out to be low. This property is interesting for applications requiring low foaming properties such as dishwashing liquid for machines. The best results are observed near and above the critical micellar concentrations and at 25 °C for both the samples.

Evolutionary medicine: A meaningful connection between omics, disease, and treatment

The evolutionary nature of diseases requires that their omics be analyzed by evolution-compatible analytical tools such as parsimony phylogenetics in order to reveal common mutations and pathways' modifications. Since the heterogeneity of the omics data renders some analytical tools such as phenetic clustering and Bayesian likelihood inefficient, a parsimony phylogenetic paradigm seems to connect between the omics and medicine. It offers a seamless, dynamic, predictive, and multidimensional analytical approach that reveals biological classes, and disease ontogenies; its analysis can be translated into practice for early detection, diagnosis, biomarker identification, prognosis, and assessment of treatment. Parsimony phylogenetics identifies classes of specimens, the clades, by their shared derived expressions, the synapomorphies, which are also the potential biomarkers for the classes that they delimit. Synapomorphies are determined through polarity assessment (ancestral vs. derived) of m/z or gene-expression values and parsimony analysis; this process also permits intra and interplatform comparability and produces higher concordance between platforms. Furthermore, major trends in the data are also interpreted from the graphical representation of the data as a tree diagram termed cladogram; it depicts directionality of change, identifies the transitional patterns from healthy to diseased, and can be developed into a predictive tool for early detection.     

Improving Arabic morphological analyzers benchmark

The various tools dedicated to Arabic natural language processing have undergone significant development during recent years. Among these tools, Arabic morphological analyzers are of great importance because they are often used within other projects that are more advanced such as syntactic parsers, search engines, machine translation systems, etc. Thus, researchers are forced to make a decision concerning which morphological analyzer to use in their research projects, and this task is very difficult since there are many criteria to take into account. In order to facilitate this choice, we considered the problem of benchmarking morphological analyzers in a previous work by proposing a solution that allows returning a set of metrics of each analyzer that are: accuracy, precision, recall, F-measure and the execution time. In this article, we present two new major improvements to our solution: the establishment of the first version of our corpus that is dedicated to the evaluation of morphological analyzers, as well as the introduction of a new metric, which combines all metrics related to results as well as the execution time of the analyzers.     

Handoff with energy awareness for future pervasive environments

Handoff management is one of the main research challenges for the realization of the envisioned mobile and wireless Internet. This is mainly due to the latency delay and energy consumption introduced during handoff, which are of major concern for real-time applications and battery-constrained mobile terminals. In this paper, we explore whether handoff management can benefit from the pervasiveness of future communication networks. The key idea is to follow the ambient intelligence paradigm for the purpose of context-aware handoff. More precisely, we focus on the Radio Frequency Identification (RFID) and Wireless Sensor and Actuator Networks (WSANs) pervasive technologies, and propose two schemes for handoff prediction at the network layer or at both link and network layers, respectively. Analytical models for their time response and energy consumption are firstly derived. Then simulation-based results show that both of our schemes can achieve 38% to 93% reduction in time response while the second scheme provides 88% energy savings, validating their superiority over the standard solutions.     

A global architecture for the Wi-family

WiMedia, Wi-Fi, WiMax, Wi-Mobile, WiRAN, the Wi-family is getting bigger; so does the network architecture. It is encouraging to see the fast development of the new IEEE wireless technologies promising the ultimate Internet service deployment on wireless and mobile infrastructures since they would offer larger bandwidth at cheaper price compared to the telecommunication wireless radio resource. However it is disquieting to see that the TCP/IP protocol stack which is supposed to be the heart of the Internet services deployment is not evolving as fast as the wireless technologies do. Here we come up with the hard question which is the network performance of the TCP/IP architecture over wireless networks. It is probably too early to decide to replace TCP/IP by another protocol stack for wireless network support, but it is important to not ignore the problem and analyse the main drawbacks of TCP/IP in wireless networks and think about a new architecture of network communication over the wireless networks. This paper provides a brief survey of what we name here the Wi-family wireless technologies, and emphasizes on new network architecture to optimize the TCP/IP behaviour worsen by the wireless characteristics.     

The missing parameter in rheology: hidden solid‐like correlations in viscous liquids,polymer melts and glass formers

BACKGROUND: Determination of dynamic relaxation consists of measuring the viscous and the elastic components of a material by generally applying a small (oscillatory) deformation. The shear stress is transmitted to the material via contact with a substrate. Dating at least back to Stokes, the no‐slip boundary condition between the fluid and the substrate is supposed to be fulfilled during this measurement. We show that the viscoelastic parameters of fluids are usually not determined under no‐slip boundary conditions and do not originate from the first linear regime. Viscous and viscoelastic fluids (entangled and unentangled polymers, glass formers) measured under no‐slip conditions exhibit a fundamentally different response with a dominant terminal solid‐like response. RESULTS: We show that the terminal behaviour of fluids such as liquid polymers or glass formers measured at the sub‐millimetre scale and far above the glass transition is not viscous but solid‐like. Instead of a viscoelastic behaviour scaling as ω and ω² (ω is the frequency) for the viscous and the elastic moduli, respectively, the dynamic response is simplified; for low gap thickness, both viscous and elastic moduli are invariant with respect to the frequency (with the elastic modulus being larger than the viscous modulus) and enhanced by two to four orders of magnitude compared to the conventional viscoelastic response. Over a critical strain amplitude, the solid‐like response decreases and is progressively replaced by the conventional viscoelastic behaviour. We discuss the implications of this observation and reconsider the assumptions inherent to a rheology measurement. CONCLUSION: The identification of so far neglected macroscopic elasticity in the fluidic state far above the glass transition temperature in entangled and unentangled polymers and glass formers shows that the liquid state is dominated by long range intermolecular interactions. This information is fundamental to understand and to foresee dynamic behaviour; it sheds further light on nonlinear phenomena such as large time scale relaxations, rheo‐thinning, violation of the no‐slip boundary condition and spectacular shear‐induced instabilities (spurt effect, ‘shark‐skin’ instabilities, gross melt fracture, etc.) that are unpredictable in the frame of the conventional viscoelastic approach. It also implies that the viscoelastic times (reptation, Rouse) in polymers are not the longest relaxation times of these materials. Copyright © 2009 Society of Chemical Industry     

Theoretical Prediction of Heats of Sublimation of Energetic Materials Using Pseudo‐Atomic Orbital Density Functional Theory Calculations

We present a predictive model for the heats of sublimation of the condensed phases of energetic materials that combine the empirical relations of Politzer with first‐principles density‐functional calculations of the electronic properties of the molecular surfaces. The distinct features of our methodology are the use of numerical pseudo‐atomic orbitals for the quantum mechanical calculation of the electronic charge density, as well as an improved technique for the molecular surface area determination. As applications, we used our model to predict heats of sublimation of energetic molecules CL‐20, HMX, RDX, TNT, FOX‐7, TATB, and LLM‐105, with the Politzer parameters fit based on a set of eight nitro‐aromatic molecules. In comparison with conventional quantum chemistry calculations, our approach is tremendously less computationally demanding, yet it still demonstrates competitive accuracy and predictive power.