Abstract

The sensitivity of a monolithically integrated semiconductor ring laser gyro is severely limited by the high value of the lock-in threshold. In this work, we calculate the lock-in threshold using perturbation theory and coupled mode theory analysis. It is shown that gyro sensitivity is limited to an input rotation rate of 10^8  deg / h due to nonlinear coupling between the countertraveling modes. This coupling arises due to the backreflection of modes from moving index gratings, induced by rotation. Lock-in threshold is directly proportional to the strength of nonlinear coupling and spatial overlap of the modes’ energy densities with periodic index perturbations.

Abstract

Most of the previously proposed schemes use temporary identities for mobile users to provide unlinkable anonymous authentication for mobile users to the satellite network control center (NCC), where the temporary identities are picked at random after each session and agreed between a mobile user U and the NCC for the next session. Although such schemes provide full anonymity and are computationally efficient, the common problem with such strategies is that an adversary is able to desynchronize the temporary identity shared between U and NCC by means of simple jamming attack at a certain round in the authentication protocol. It results in the denial of all future sessions unless U re‐registers a new identity at the NCC. In this paper, we propose a new authentication scheme for mobile satellite networks. We avoid using synchronized temporary identities, which are always vulnerable to desynchronization attacks. We also avoid multi‐round authentication phase in order to reduce the jamming effect. Instead, a mobile user is able to create a new blinded version of his clear identity for each established session noninteractively, allowing him to anonymously authenticate himself to NCC in a fully unlinkable fashion. Moreover, in few milliseconds and one move non‐interactive way, U is able to establish a session key with NCC in a fully anonymous and authenticated way. Our new scheme uses recent advances in elliptic curve cryptography, and hence, it is efficient for implementation on mobile devices with limited resources. Through the rigorous security analysis using the broadly accepted Burrows–Abadi–Needham logic, informal security analysis, and the simulation for formal security verification using the widely known automated validation of Internet security protocols and sapplications tool, we show that our scheme is secure against various known attacks. Copyright © 2017 John Wiley & Sons, Ltd.

Abstract

Session initiation protocol (SIP) is a widely used authentication protocol for the Voice over IP communications. Over the years, several protocols have been proposed in the literature to strengthen the security of SIP. In this paper, we present an efficient elliptic curve cryptography (ECC)‐based provably secure three‐factor authentication and session key agreement scheme for SIP, which uses the identity, password, and personal biometrics of a user as three factors. Our scheme aims to resolve the security weaknesses and drawbacks in existing SIP authentication protocols. In addition, our scheme supports password and biometric update phase without involving the server and the user mobile device revocation phase in case the mobile device is lost/stolen. Formal security analysis under the standard model and the broadly accepted Burrows–Abadi–Needham logic ensures that the proposed scheme can withstand several known security attacks. The proposed scheme has also been analyzed informally. Simulation for formal security verification using the widely known automated validation of internet security protocols and applications tool shows the replay, and the man‐in‐the‐middle attacks are protected by the scheme. High security and low communication and computation costs make the proposed scheme more suitable for practical application as compared with other existing related ECC‐based schemes. Copyright © 2016 John Wiley & Sons, Ltd

Abstract

Many aspects of program analysis are related to CFL (context-free language) constrained path problems on graphs. A path is constrained by requiring its list of edge labels to form a string that is a member of the associated CFL. Constrained shortest path problems give O(n3/ log n)-bottlenecks for program analysis, where n is the number of nodes. Labeled path problems also have many other applications. Assume two terminals (parenthesis) in a Dyck CFL. Given any two vertices s and t and the output of Nykanen and Ukkonen's exact integer path length algorithm. then this paper finds a minimal-cost point-to-point Dyck path cost in such edge-labeled digraphs in O(n2 log n) additional operations. This paper is on the DAG (directed acyclic graph) case. Our result depends on a special case of the exact integer path length problem of Nykanen and Ukkonen that costs O(n3). A new algorithm is introduced that joins …

Abstract

Software is finding place in deeply embedded systems to large scale distributed systems of cloud service providers such as Amazon and Google. Due to the concurrent and distributed nature of this software, it is hard to test for correctness of such systems in a foolproof manner. Explicit state model checking is an approach in which we build a model of the system and specify the properties it should hold. Then we construct a state transition system from the model and check if it satisfies the specified properties. There are two kinds of properties of interest: safety and liveness. In this paper, we focus our attention on safety verification, which involves checking if the states that are generated in the transition system satisfy some predicate formulae specified in the form of assertions. The main problem here is that the number of states in the transition system grows exponentially with the number of bits required to store the …

Abstract

Bimetallic nanoparticles (NPs) have been shown to exhibit certain advantages over pure NPs in catalysis due to a synergistic effect. It is common to disperse NPs in a polymer matrix such as polyvinylpyrrolidone (PVP) to prevent flocculation, which imparts considerable electronic effects on the NPs. In the present study, the interactions between aqueous solutions of N-ethylpyrrolidone (EP, system chosen to model the monomeric form of PVP) and Au/Pd bimetallic NPs, which are relevant in catalysis, have been investigated using molecular dynamics simulations and density functional theory (DFT) method. The adequacy of the force fields used was assessed based on their ability to reproduce the structures and adsorption energies obtained using DFT calculations. The interactions of NPs with the environment were studied at various concentrations of aqueous solutions of EP to examine the strength of NP–EP and NP …

Abstract

Multidrug resistance in Mycobacterium tuberculosis (M. Tb) and its coexistence with HIV are the biggest therapeutic challenges in anti-M. Tb drug discovery. The current study reports a Virtual Screening (VS) strategy to identify potential inhibitors of Mycobacterial cyclopropane synthase (CmaA1), an important M. Tb target considering the above challenges. Five ligand-based pharmacophore models were generated from 40 different conformations of the cofactors of CmaA1 taken from molecular dynamics (MD) simulations trajectories of CmaA1. The screening abilities of these models were validated by screening 23 inhibitors and 1398 non-inhibitors of CmaA1. A VS protocol was designed with four levels of screening i.e., ligand-based pharmacophore screening, structure-based pharmacophore screening, docking and absorption, distribution, metabolism, excretion and the toxicity (ADMET) filters. In an …

Abstract

Gold clusters are currently regarded as new-generation catalysts owing to their exceptional efficiency in accelerating several classes of reactions. Density functional theory (DFT) is the method of choice for the investigation of energy pathways of reactions assisted by metal nanoparticles due to their computational efficiency. However, the reliability of such theoretical studies depends to a large extent on the choice of the DFT functional used. In the present work, the performance of a series of DFT-based functionals to accurately model the prototypical CO oxidation reaction catalyzed by a cluster has been examined by comparing the results with those obtained from high-level ab initio CCSD(T) method. This comparison study has been carried along the two possible pathways [Eley–Rideal (ER) and the Langmuir–Hinshelwood (LH)]. No significant differences among the DFT functionals were observed in …

Abstract

Wireless sensor networks (WSNs) have several applications ranging from the civilian to military applications. WSNs are prone to various hole attacks, such as sinkhole, wormhole, blackhole, and greyhole. Among these hole attacks, the sinkhole attack is the malignant one. A sinkhole attack allows a malicious node, called the sinkhole node, advertises a best possible path to the base station (BS). This misguides its neighbors to utilize that path more frequently. The sinkhole node has the opportunity to tamper with the data, and it also performs the modifications in messages or it drops messages or it produces unnecessary delay before forwarding them to the BS. On the basis of these malicious acts that are performed by a sinkhole attacker node, we consider three types of malicious nodes in a WSN: sinkhole message modification node (SMD), sinkhole message dropping node (SDP), and sinkhole message delay node (SDL). None of the existing techniques in the literature is capable to handle all three types of nodes at a time. This paper presents a new detection scheme for the detection of different types of sinkhole nodes for a hierarchical wireless sensor network (HWSN). To the best of our knowledge, this is the first attempt to design such a detection scheme in HWSNs which can detect SMD, SDP, and SDL nodes. In our approach, the entire HWSN is divided into several disjoint clusters, and each cluster has a powerful high-end sensor node (called a cluster head), which is responsible for the detection of different sinkhole attacker nodes if present in that cluster. We simulate our scheme using the widely-accepted NS2 simulator for measurement of various network parameters. The proposed scheme achieves around 95% detection rate and 1.25% false positive rate. These factors are significantly better than the previous related schemes. Furthermore, the computation and communication efficiency is achieved in our scheme. As a result, our scheme seems suitable for the sensitive critical applications, such as military applications.

Abstract

In [1] the authorship was originally shown as “Ashok Kumar Das, Dheerendra Mishra and Sourav Mukhopadhyay”. This has now been corrected to “Dheerendra Mishra, Ashok Kumar Das and Sourav Mukhopadhyay”. We apologize for any inconvenience caused … 1. Mishra D, Das AK, Mukhopadhyay S. An anonymous and secure biometric-based enterprise digital rights management system for mobile environment. Security and Communica- tions Networks2015;8:3383–3404 . doi:10.1002/sec.1266." … SECURITY AND COMMUNICATION NETWORKS Security Comm. Networks 2016; 9:3762 … Published online 18 August 2016 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/sec.1604