QoS management in mobile IP networks using a terminal assistant

This paper describes a signalling environment for Quality of Service (QoS) negotiation and advance resource reservation in mobile IP networks. This environment is built in conformance with the generic signalling environment, which is standardized by the NSIS IETF working group. The advanced resource reservation protocol, called MQoS NSLP, is based on the QoS NSLP signalling application. It provides to mobile terminals the QoS required based on the user's mobility and QoS profile. In this work, we investigate the use of some techniques of the AI (Artificial Intelligence) domain to implement a user interface called NIA (Negotiation Individual Assistant) in order to determine the QoS profile and negotiate the QoS parameters in the new domain after the handover. Therefore, we use connectionist learning in the management of the negotiation profiles and agent technology to help the user choose the best service provider, dynamically negotiate the QoS on the user's behalf, and follow the user's behaviour to be able to anticipate the negotiation and manage renegotiation. The advance resource reservation is based on an object MSpec (Mobility Specification) which determines the future location of the mobile terminal. The MSpec object is a part of the mobility and QoS profile and is determined by the NIA in the mobile terminal. Copyright © 2008 John Wiley & Sons, Ltd.     

Residual stresses,shrinkage, and warpage of complex injection molded products: Numerical simulation and experimental validation

A numerical simulation model for predicting residual stresses and residual deformations which arise during the injection molding of thermoplastic polymers in the post-packing stage has been developed. A thermoviscoelastic model with volume relaxation is used for the calculation of residual stresses. The finite element method employed is based on the theory of shells as an assembly of flat elements. This theory is well suited for thin injection molded products of complex shape. The approach allows the prediction of residual deformations and residual stresses layer by layer like a truly three-dimensional calculation, while reducing the computational cost significantly. The hole drilling technique is used to measure the residual stresses across the thickness of the product. A three-dimensional laser digitizing system, an image processing technique and a dual displacement transducer system are used to measure the warpage. Experiments are carried out on polycarbonate and high density polyethylene parts. Numerical results are in qualitative agreement with experimental observations, i.e., the skin of the box is surrounded by a compressive region while the core region is in traction. The trend of both the experimental and the predicted residual stress profiles is close. Different examples are presented to illustrate the influence of the geometrical complexity of the shape on the final deformations and residual stresses. The influence of the mold temperature on residual stresses and warpage is also analyzed.     

Further results on differential detection of GMSK signals

We evaluate the performance, in terms of bit-error rate, of 1- and 2-bit differential detectors for Gaussian minimum-shift keying (GMSK) signals by using a very fast numerical technique which makes use of the saddle point approximation. Moreover, the performance of each detector is optimized by using a closed-form expression of the optimum threshold in the slicer     

The substitution pattern of anthocyanidins affects different cellular signaling cascades regulating cell proliferation

The aglycons of the most abundant anthocyanins in food, cyanidin (cy) and delphinidin (del), represent potent inhibitors of the epidermal growth factor receptor (EGFR). Structure-activity studies show that the presence of vicinal hydroxy substituents at the phenyl ring at the 2-position (B-ring) is crucial for target interaction. The presence of a single hydroxy group or introduction of methoxy substituents at the B-ring results in a substantial loss of inhibitory properties. However, biological activity is not exclusively limited to compounds bearing vicinal hydroxy groups. A contradictory structure-activity relationship is observed for the inhibition of cAMP-specific phosphodiesterases (PDEs). Of the anthocyanidins tested, malvidin, bearing methoxy substituents in the 3'- and 5'-positions, most effectively inhibited cAMP hydrolysis. The absence of methoxy groups and/or replacement by hydroxy substituents was found to strongly diminish PDE-inhibitory properties. We found that either effective EGFR inhibition or effective PDE inhibition is required to achieve a shut-down of the central mitogen-activated protein kinase (MAPK) pathway, a signaling cascade crucial for the regulation of cell growth. This is consistent with the finding that efficient reduction of cell growth is limited to anthocyanidins that are potent EGFR- or PDE-inhibitors including cy and del or malvidin (mv), respectively. In summary, depending on the substitution pattern at the B-ring, anthocyanidins interfere with different signaling cascades involved in the regulation of cell growth.     

Relationship between Governance Structure and Financial Performance in Construction

Although corporate governance has emerged as an issue of considerable importance in shaping the organizational structure and the vision of the firm, this entity has yet to receive sufficient scrutiny in the construction industry. The purpose of this study is to determine the extent by which the configuration of corporate governance may impact on the financial performance of construction firms. The investigation utilizes 100 companies of differing sizes. The analysis reveals that a critical mass of outside independent directors and the dissociation of the roles of CEO and Chairmanship of the board do translate into superior financial market returns for the firms. Other corporate governance variables have no apparent impact on the financial performance of the firms. These findings are significant to construction firms that are already established or in the process of being formed.     

Operating and powering optical fiber network

Fiber-in-the-loop (FITL) systems enable the distribution transport of existing telecommunications services and future broadband services over fiber optic media. An FITL system comprises a host digital terminal (HDT) connected to some number of optical network units (ONUs) via a fiber optic passive distribution network (PDN). Each ONU provides metallic service interfaces via short drops consisting of metallic wire pairs or coaxial cable. FITL systems that carry plain old telephony services (POTS) are referred to as “POTS FITL” systems. FITL systems that deliver VDT services or combined VDT and telephony services are referred to as “VDT FITL” systems. There are a number of architectural alternatives for VDT FITL, including configurations involving the use of parallel technologies for transporting video signals in the distribution. The authors discuss network operations and powering in particular     

Mesh cutting during real-time physical simulation

The ability to cut through meshes in real-time is an essential ingredient in a number of practical interactive simulations. Surgical simulation, cloth design, clay sculpting and many other related VR applications require the ability to introduce arbitrary discontinuities through models to separate, reposition, and reshape various pieces of the model as needed for the target application. In addition, in order to provide the necessary realism for these applications, model deformations must be computed from an underlying physically-based model—most commonly a continuum-based finite element model.In this work, we present a method for representing and computing, at interactive rates, the deformations of a mesh whose topology is being dynamically modified with multiple virtual tools. The method relies on introducing controlled discontinuities in the basis functions used to represent the geometry of deformation, and on fast incremental methods for updating global model deformations. The method can also generate the forces needed for force rendering in a haptic environment. The method is shown to scale well with problem size (linearly in the number of nonzeros of the Cholesky factor) allowing realistic interaction with fairly large models.     

Density-Dependence of Surface Transport in Tellurium-Enriched Nanograined Bulk Bi2Te3

Three-dimensional topological insulators (3D TI) exhibit conventional parabolic bulk bands and protected Dirac surface states. A thorough investigation of the different transport channels provided by the bulk and surface carriers using macroscopic samples may provide a path toward accessing superior surface transport properties. Bi₂Te₃ materials make promising 3D TI models; however, due to their complicated defect chemistry, these materials have a high number of charge carriers in the bulk that dominate the transport, even as nanograined structures. To partially control the bulk charge carrier density, herein the synthesis of Te-enriched Bi₂Te₃ nanoparticles is reported. The resulting nanoparticles are compacted into nanograined pellets of varying porosity to tailor the surface-to-volume ratio, thereby emphasizing the surface transport channels. The nanograined pellets are characterized by a combination of resistivity, Hall- and magneto-conductance measurements together with (THz) time-domain reflectivity measurements. Using the Hikami-Larkin-Nagaoka (HLN) model, a characteristic coherence length of ≈200 nm is reported that is considerably larger than the diameter of the nanograins. The different contributions from the bulk and surface carriers are disentangled by THz spectroscopy, thus emphasizing the dominant role of the surface carriers. The results strongly suggest that the surface transport carriers have overcome the hindrance imposed by nanoparticle boundaries.     

The quantitative detection of free radicals on mechanically formed polymer surfaces

Mechanochemical reactions are becoming increasingly important; yet, quantitative data on mechanoradicals are sparse. A study was undertaken to determine the surface concentration of free radicals which are available for reaction when chemical bonds are broken by mechanically forming fresh polymer surface. Polyethylene and polypropylene were cut under a benzene solution of the free-radical scavenger diphenylpicryl-hydrazyl, using countersinks as the cutting tools. Accurate surface area measurements of the polymer shavings were made. Surface free-radical densities up to 2 × 10¹³/cm² for polyethylene and 9 × 10¹³/cm² for polypropylene were determined. The physical conditions of the test and of the cutting tool were found to have an effect on the results, but not as profound as that of base polymer.     

Feasibility of a New Moving Collimator for Industrial Backscatter Imaging

Conventional direct radiography may fail to successfully produce images of corrosion in large pipes containing liquid and in tanks because the attenuation can be very high. It also fails when either side of the object is not accessible. These limitations do not exist in backscatter imaging because it is a one-sided imaging technique. However, backscatter imaging can be slow. In this study, the feasibility of a new backscatter imaging system based on a moving collimator that can produce images quickly is studied. Backscattered radiation from a broad-beam industrial X-ray machine is collimated by a special collimator to allow only parallel scattered radiation to pass and reach the image plate. Because part of the backscattered radiation can be stopped by the collimator septa, the collimator is put into motion; this allows a complete image to be revealed. An electro-mechanical system is designed to move the collimator either in steps or continuously. The distance, speed and direction of the movement are controlled by a smart motor using LabVIEW. Images of Polyvinylchloride (PVC) and aluminum objects are shown. Moving collimators can be added to existing radiographic systems to make them useful for both direct and backscatter imaging.