Seamless handover integrated solution for video transmission over proxy mobile IPv6 in a micro mobility domain

Seamless communication is becoming one of the most important issues for the next generation of mobile and wireless networks. In this context, seamless is referred to users that are free to roam around different networks and at the same time stay connected without any disturbance to the ongoing session during the handover process from one network to another. The handover process between these networks spawns long delay or latency, high packet loss, and fewer throughputs which may degrade the performance of real-time applications during the handover process. Therefore, in order to resolve these problems, a new protocol has been proposed by Network-based Localized Mobility Management working group of Internet Engineering Task Force under network-based mobility management protocol. Although, this protocol managed to minimize the problems related to network switching, it still suffers several drawbacks during the handover process especially when the movement speed of mobile user is high. In this paper, we present a new approach which is a network-based mobility management protocol that aims to reduce the lengthy handover latency, jitter, high packet loss, and increase throughput and the performance of video transmission during the high speed mobility. The proposed approach namely Seamless Handover Integrated Solution consists of mobility prediction method, a set of Internet Control Message Protocol version 6 (ICMP6) messages which are effective in terms of handover optimization.     

Why patients fail to attend psychiatric outpatient follow-up: a pilot study

BACKGROUND/AIM: Traditionally, orthotopic liver transplantation has consisted of a total native hepatectomy that included retrohepatic inferior vena cava. The so-called "piggyback" technique was described by Tzakis et al. (2). It consists of a recipient hepatectomy with preservation of the native retrohepatic IVC and subsequent anastomosis of the homograft suprahepatic IVC to a cuff fashioned from the recipient's suprahepatic veins. In this study, a single surgeon's experience with both techniques during the same period of time is discussed to analyze any significant differences in survival, intraoperative blood loss, length of stay in the ICU, and total length of stay in the hospital. MATERIALS AND METHODS: Over a three year period, 128 patients were transplanted at the University of Pittsburgh. Of these, 66 patients (51.6%) had a piggyback (PB) operation while the remaining 62 (48.4%) had a "standard" (ST) operation. RESULTS: The actual 6 month survival was 81.8% in the PB group (54/66) and 74.2% in the ST group (46/62), with no statistical difference between the two. The median intraoperative blood usage was 6 units for the PB group versus 10 units for the ST group (p > 0.02). The median ICU length of stay was the same at 4 days, as was the total hospitalization duration, 21 days. The in-hospital deaths were included in the analysis. CONCLUSIONS: The piggyback technique has some advantages, including less bleeding and absence of brachial plexus or phrenic nerve injury. Several other important considerations are discussed. In conclusion, the results with the piggyback technique are equivalent to those obtained with the standard approach.     

Error compensation in machine tools — a review: Part II: thermal errors

Accuracy of machined components is one of the most critical considerations for any manufacturer. Many key factors like cutting tools and machining conditions, resolution of the machine tool, the type of workpiece etc., play an important role. However, once these are decided upon, the consistent performance of the machine tool depends upon its ability to accurately position the tool tip vis-à-vis the required workpiece dimension. This task is greatly constrained by errors either built into the machine or occurring on a periodic basis on account of temperature changes or variation in cutting forces. The three major types of error are geometric, thermal and cutting-force induced errors. Geometric errors make up the major part of the inaccuracy of a machine tool, the error caused by cutting forces depending on the type of tool and workpiece and the cutting conditions adopted. This part of the paper attempts to review the work done in analysing the various sources of geometric errors that are usually encountered on machine tools and the methods of elimination or compensation employed in these machines. A brief study of cutting-force induced errors and other errors is also made towards the end of this paper.     

Integration of functional reliability analysis with hardware reliability: An application to safety grade decay heat removal system of Indian 500 MWe PFBR

A passive system can fail either due to classical mechanical failure of components, referred to as hardware failure, or due to the failure of physical phenomena to fulfill the intended function, referred to as functional failure. In this paper a methodology is discussed for the integration of these two kinds of unreliability and applied to evaluate the integrated failure probability of the passive decay heat removal system of Indian 500 MWe prototype fast breeder reactor (PFBR). The probability of occurrence of various system hardware configurations is evaluated using the fault tree method and functional failure probabilities on the corresponding configurations are determined based on the overall approach reported in the reliability methods for passive system (RMPS) project. The variation of functional reliability with time, which is coupled to the probability of occurrence of various hardware system configurations is studied and incorporated in the integrated reliability analysis. It is observed that this consideration of the dependence of functional reliability on time will give significant advantages on system reliability. The integrated reliability analysis is also explained using an event tree. The impact of the provision for forced circulation in the primary circuit on functional reliability is also studied with this procedure and it is found that the forced circulation capability helps to bring down the total decay heat removal failure probability by lowering the peak temperatures after the reactor shut down.     

Novel ceramic substrates for high Tc superconductors

A group of complex perovskite oxides REBa₂NbO₆ (RE=La and Dy) have been synthesized and developed for their use as substrates for both YBa₂Cu₃O_7-δ and Bi(2223) superconductors. These materials have a complex cubic perovskite (A₂BB′O₆) structure with lattice constants,a=8·48?8·60 Å. REBa₂NbO₆ did not show any phase transition in the temperature range 30–1300°C. The thermal expansion coefficient, thermal diffusivity and thermal conductivity values of REBa₂NbO₆ are favourable for their use as substrates for highT _c superconductors. The dielectric constant and loss factor of REBa₂NbO₆ are in a range suitable for their use as substrates for microwave applications. Both YBa₂Cu₃O_7-δ and Bi(2223) superconductors did not show any detectable chemical reaction with REBa₂NbO₆ even under extreme processing conditions. Dip coated YBa₂Cu₃O_7-δ thick films on polycrystalline REBa₂NbO₆ substrate gave aT _c(0) of 92 K and a current density of ～1·1×10⁴ A/cm² and Bi(2223) thick film on polycrystalline REBa₂NbO₆ substrate gave aT _c(0) of 110 K and a current density of ～ 4×10³ A/cm² at 77 K and zero magnetic field. A laser ablated YBa₂Cu₃O_7-δ thin film deposited on polycrystalline REBa₂NbO₆ substrate gave aT _c(0) of 90 K and a current density of ～5×10⁵ A/cm².     

Phase Evolution and Thermal Analysis of Nanocrystalline AlCrCuFeNiZn High Entropy Alloy Produced by Mechanical Alloying

A multi-component nanocrystalline AlCrCuFeNiZn high entropy alloy with 12 nm crystallite size was successfully synthesized using high energy ball milling. The progress of solid solution formation during milling was analyzed using XRD. A major portion of the HEA is observed to be BCC in crystal structure after 30 h of milling. Thermal analysis showed that HEA powders exhibited exponential oxidation characteristics. Thermal analysis showed that low activation energy was sufficient to start recrystallization because of high energy stored in the milled powders. The crystallite size after consolidation is in nanocrystalline range due to the sluggish diffusion of atoms and nanotwinning. After consolidation, the crystallite size is around 79 nm. Samples sintered at 850 °C for 2 h exhibited high hardness values of 700 ± 15 HV_1.0, major volume fraction of the phases are having FCC crystal structure along with a minor phase having BCC crystal structure. Due to positive enthalpy mixing of Cu with other elements, decomposition of BCC to new FCC phases occurs.     

Synthesis,magnetic and Mössbauer study of ε-FexN (2 < x < 3) nanowires

Several micro meter long nanowires of ε-Fe_xN (2 < x < 3) are synthesized through a reduction nitridation method of Fe-NTA precursor formed by a hydrothermal method. The formation of pure iron nitride nanowires is confirmed by XRD. SEM analysis shows the porous nature of the iron nitride nanowires, which will enhance its suitability in catalysis. The field dependent magnetic behavior shows the ferromagnetic nature of the iron nitride nanowires. An appreciably good magnetization value (71 emu/g) and low coercivity (24 Oe) of the system makes it suitable for magnetic recording head applications. The room temperature Mössbauer study of the pristine nitride nanowires shows the existence of two iron sites corresponding to Fe (II) and Fe (III) indicating structural disorder.     

Wavelength assignment with sparse wavelength conversion for optical multicast in WDM networks

This paper addresses the problem of multicast wavelength assignment for sparse wavelength conversion (MWA-SWC) in wavelength-routed wavelength-division-multiplexing (WDM) networks. It aims to optimally allocate the available wavelength for each link of the multicast tree, given a sparse wavelength conversion network and a multicast request. To our knowledge, little research work has been done to address this problem in literature.In this paper, we propose a new technique called MWA-SWC algorithm to solve the problem. The algorithm first maps the multicast tree from the sparse conversion case to the full conversion case by making use of a novel virtual link method to carry out the tree mapping. The method provides a forward mapping to generate an auxiliary tree as well as a reverse mapping to recover the original tree. Applying the auxiliary tree, we propose a dynamic programing algorithm for the wavelength assignment (WA) aiming to minimize the number of wavelength converters (NWC) required. Simulation results show that our new algorithm outperforms both random and greedy algorithms with regard to minimizing the NWC. Testing on various scenarios by varying the number of wavelength conversion nodes in the tree has confirmed the consistency of the performance. The primary use of the MWA-SWC algorithm is for static traffic. However, it can also serve as a baseline for dynamic heuristic algorithms. Typically, the MWA-SWC algorithm will provide great benefit when the number of available wavelengths on each link of the multicast tree is relatively large and the performance advantage is significant.     

Constraint gain

In digital storage systems where the input to the noisy channel is required to satisfy a modulation constraint, the constrained code and error-control code (ECC) are typically designed and decoded independently. The achievable rate for this situation is evaluated as the rate of average intersection of the constraint and the ECC. The gap from the capacity of the noisy constrained channel is called the constraint gain, which represents the potential improvement in combining the design and decoding of the constrained code and the ECC. The constraint gain is computed for various constraints over the binary-input additive white Gaussian noise (AWGN) channel (BIAWGNC) as well as over intersymbol interference (ISI) channels. Finally, it is shown that an infinite cascade of reverse concatenation with independent decoding of constraint and ECC has a capacity equal to the rate of average intersection.     

Support Vector Machines Model for Classification of Thermal Error in Machine Tools

This paper addresses a change in the concept of machine tool thermal error prediction which has been hitherto carried out by directly mapping them with the temperature of critical elements on the machine. The model developed herein using support vector machines, a powerful data-training algorithm, seeks to account for the impact of specific operating conditions, in addition to temperature variation, on the effective prediction of thermal errors. Several experiments were conducted to study the error pattern, which was found to change significantly with variation in operating conditions. This model attempts to classify the error based on operating conditions. Once classified, the error is then predicted based on the temperature states. This paper also briefly describes the concept of the implementation of such a comprehensive model along with an on-line error assessment and calibration system in a PC-based open-architecture controller environment, so that it could be employed in regular production for the purpose of periodic calibration of machine tools.