Security Clustering: A Network-wide Secure Computing Mechanism in Pervasive Computing

Abstract. In this paper, we introduce a new security paradigm, called security clustering, for pervasive computing environment that enables network-wide defend against increasing evolutionary attacks on the heterogeneous network and hosts. Security clustering make use of dynamic security context exchange between cluster members and distributed information sharing to achieve scalable and efficient cooperation

Trace-based fault simulation methods

Trace-based methods have been shown to be more effective than traditional fault simulation methods. The goal of this dissertation is to further accelerate trace-based fault simulation for combinational and synchronous sequential circuits. The use of general purpose shared memory multiprocessors for effective trace-based fault simulation is also investigated. Significant improvements in the speed of fault simulation of combinational circuits have been achieved by combining parallel pattern simulation of the fault-free circuit with tracing based methods for identifying detected faults. We present methods of achieving further speed improvements by reducing both the amount of backtracing within fanout-free regions and explicit fault simulation of stem faults. Results of simulating a set of benchmark combinational circuits with the proposed methods indicate that they are faster than other published methods, both with and without fault-dropping. We improve the speed of fault simulation of synchronous sequential circuits by using a linear iterative array model for such a circuit, and combining parallel fault simulation with surrogate fault simulation. Fault propagation of faults whose fault effects have not propagated from state variables in the previous time frame can be determined by backtracing from their surrogate lines and using the concept of surrogate faults. The others and surrogate faults need explicit forward propagation. Parallel fault simulation is used for the explicit forward propagation. Also, backtracing is extended to handle 0, 1, and X (unknown) signal values to represent unknown initial states of the sequential circuit. The results of simulating a set of benchmark sequential circuits show that execution time is reduced by 7 $\sim$ 54%, compared to a method which has been reported to be one of the fastest. Trace-based method is parallelized on a general-purpose multiprocessor with shared memory and the effect of the number of processors on speed-up of simulation and processor utilization is studied. The algorithm is based on a synchronous simulation method using a global simulation clock and task partitioning

An Efficient Resource Management Protocol for Handling Small Resource in Wireless Sensor Networks

Copyright © 2013 Wan-Hee Cho et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Wireless sensor nodeswith single chipsmay have insufficient resources for certain applications.We propose a resourcemanagement protocol for applications with constrained resources to improve effectiveness by borrowing resources from a resource management server. 1

Predictive Mobility Support with Secure Context Management for Vehicular Users *

Abstract. This paper presents a predictive mobility management framework with the secure context management in mobile networks. We devised the authentication method for seamless handovers that exploit the knowledge of the mobility prediction. Previous Access Router (AR) forwards the preestablished context information to the new AR in the predicted target wireless cell where MN might move in the near future. Therefore the context for autonomous services is available in the right place at right time

Effects of sway and roll excitations on sloshing loads in a KC-1 membrane LNG tank

This study investigates the effects of sway and roll excitations on sloshing liquid loads in a tank, using Ansys Fluent software. The model considered in the study is a 1:50 scaled membrane-type tank, based on a KC-1 membrane LNG tank designed by Korea Gas Corporation (KOGAS). The volume of fluid (VOF) method is used to track the free surface inside the tank, and the standard k-ε model is applied to express the turbulent flow of the liquid. To explore the motion of the tank under excitation, a user-defined function (UDF) and a dynamic mesh technique are employed to control the external forces exerted on the tank through its motion. The results, in the form of time series data on the sloshing pressures in the tank under pure sway, roll, and coupled sway-roll, are analysed, with specific ranges for the excitation amplitudes and frequencies. We show that variations in excitation frequency and amplitude significantly influence the sloshing loads. Sloshing loads are found to intensify when the excitation frequency matches the tank’s primary natural frequency, 1.0 ω'1. Furthermore, with coupled sway-roll excitations, the sloshing loads are weakened when the sway and roll are in-phase and are intensified when these are out-of-phase. Fast Fourier transform analysis provides insights into the frequency domain, showing that the dominant frequency is 0.88 Hz and it is approximately equal to the tank’s primary natural frequency, 1.0 ω'1

Effects of Sway and Roll Excitations on Sloshing Loads in a KC-1 Membrane LNG Tank

This study investigates the effects of sway and roll excitations on sloshing liquid loads in a tank, using Ansys Fluent software. The model considered in the study is a 1:50 scaled membrane-type tank, based on a KC-1 membrane LNG tank designed by Korea Gas Corporation (KOGAS). The volume of fluid (VOF) method is used to track the free surface inside the tank, and the standard k-ε model is applied to express the turbulent flow of the liquid. To explore the motion of the tank under excitation, a user-defined function (UDF) and a dynamic mesh technique are employed to control the external forces exerted on the tank through its motion. The results, in the form of time series data on the sloshing pressures in the tank under pure sway, roll, and coupled sway-roll, are analysed, with specific ranges for the excitation amplitudes and frequencies. We show that variations in excitation frequency and amplitude significantly influence the sloshing loads. Sloshing loads are found to intensify when the excitation frequency matches the tank’s primary natural frequency, 1.0 ω1′. Furthermore, with coupled sway-roll excitations, the sloshing loads are weakened when the sway and roll are in-phase and are intensified when these are out-of-phase. Fast Fourier transform analysis provides insights into the frequency domain, showing that the dominant frequency is 0.88 Hz and it is approximately equal to the tank’s primary natural frequency, 1.0 ω1′

Properties of Polymer Nanocomposites Useful for Dental Restoration

Visible-light activated polymer nanocomposites (PNC) were designed to be used for dental restoration. Hybrid-filler composed of barium silicate and nano-sized silica was adopted as a filler system. To improve the interfacial be havior of the resin matrix of bisphenol A glycerolate methacrylate/triethyleneglycol dimethacrylate, the surface of filler was hydrophobically treated with a silane coupling agent. Mechanical properties of PNC were investigated by measuring the abrasion resistance, and it was discovered that PNC showed excellent properties with an increase of nanofiller content. However, the polymerization shrinkage was consistently maintained under 3 vol% and the shrinkage continued even after photo-polymerization. In addition, a slight color difference between PNC specimens was observed with increase of nanofiller content