A Novel Multi-Path Anonymous Randomized Key Distribution Scheme for Geo Distributed Networks

A major concern in distributed networks is the ability to provide acceptable levels of security. This is achieved by using encryption and authentication mechanisms that depend on encryption keys. However, given the ever-expanding nature of the network, it is difficult to keep setting up authorities that can aid the key-exchange process. This paper presents a novel solution to the challenge of exchanging keys of a large, distributed network without the need to set up additional authorities. The key-exchange scheme presented takes advantage of features such as packet anonymity, random selection and a multi-path approach for the exchange process. The paper also discusses the effectiveness of the proposed scheme against various threat scenarios

Connectivity and coverage in machine-type communications

Machine-type communication (MTC) provides a potential playground for deploying machine-to-machine (M2M), IP-enabled 'things' and wireless sensor networks (WSNs) that support modern, added-value services and applications. 4G/5G technology can facilitate the connectivity and the coverage of the MTC entities and elements by providing M2M-enabled gateways and base stations for carrying traffic streams to/from the backbone network. For example, the latest releases of long-term evolution (LTE) such as LTE-Advanced (LTE-A) are being transformed to support the migration of M2M devices. MTC-oriented technical definitions and requirements are defined to support the emerging M2M proliferation. ETSI describes three types of MTC access methods, namely a) the direct access, b) the gateway access and c) the coordinator access. This work is focused on studying coverage aspects when a gateway access takes place. A deployment planar field is considered where a number of M2M devices are randomly deployed, e.g., a hospital where body sensor networks form a M2M infrastructure. An analytical framework is devised that computes the average number of connected M2M devices when a M2C gateway is randomly placed for supporting connectivity access to the M2M devices. The introduced analytical framework is verified by simulation and numerical results

Connectivity and coverage in machine-type communications

Machine-type communication (MTC) provides a potential playground for deploying machine-to-machine (M2M), IP-enabled 'things' and wireless sensor networks (WSNs) that support modern, added-value services and applications. 4G/5G technology can facilitate the connectivity and the coverage of the MTC entities and elements by providing M2M-enabled gateways and base stations for carrying traffic streams to/from the backbone network. For example, the latest releases of long-term evolution (LTE) such as LTE-Advanced (LTE-A) are being transformed to support the migration of M2M devices. MTC-oriented technical definitions and requirements are defined to support the emerging M2M proliferation. ETSI describes three types of MTC access methods, namely a) the direct access, b) the gateway access and c) the coordinator access. This work is focused on studying coverage aspects when a gateway access takes place. A deployment planar field is considered where a number of M2M devices are randomly deployed, e.g., a hospital where body sensor networks form a M2M infrastructure. An analytical framework is devised that computes the average number of connected M2M devices when a M2C gateway is randomly placed for supporting connectivity access to the M2M devices. The introduced analytical framework is verified by simulation and numerical results

Razvoj i vrednovanje lako topljivih tableta kompleksa meloksikama s β-ciklodekstrinom pripravljenih izravnom kompresijom

The aim of this study was to prepare fast-dissolving tablets of meloxicam after its complexation with β-cyclodextrin (β-CD) and to investigate the effect of using different superdisintegrants on the disintegration and release of meloxicam from the tablets. A complex of meloxicam with β-CD was prepared by spray drying and then compressed in the form of tablets utilizing the direct compression technique. Three superdisintegrants were employed at various levels sodium starch glycolate, croscarmellose sodium, and crospovidone. Co-spray dried micro-crystalline cellulose and mannitol (Avicel HFE-102) were used as diluents in the tablets. Prior to compression, the pre-compression parameters showed satisfactory flow properties. Post-compression parameters showed that all tablet formulations had acceptable mechanical properties. Wetting and disintegration times were prolonged by increasing the level of sodium starch glycolate in the tablets. This was attributed to the formation of a viscous gel layer around the tablets by sodium starch glycolate whereas this effect was not observed with croscarmellose sodium and crospovidone. Dissolution studies showed fast release of meloxicam except in tablets containing a high level of sodium starch glycolate. Complexation of meloxicam with β-CD significantly improved the solubility of the drug and improved the mechanical properties of tablets produced by direct compression.Cilj rada bio je priprava lako topljivih tableta kompleksa meloksikama s β-ciklodekstrinom (β-CD) te ispitati utjecaj različitih superdezintegratora na raspadljivost tableta i oslobađanje meloksikama. Kompleks meloksikama s β-CD pripravljen je metodom sušenja sprejem, a komprimiran je u tablete metodom izravne kompresije. U pripravi tableta korištene su tri različite količine triju superdezintegratora: natrijev škrobni glikolat, natrijeva sol kroskarmeloze i krospovidon, dok su mikrokristalinična celuloza i manitol (Avicel HFE-102) upotrijebljeni kao punila. Predkompresijski parametri ukazivali su na zadovoljavajuću tečnost. Postkompresijski parametri pokazali su da sve tablete imaju prihvatljiva mehanička svojstva. Vlaženje i vrijeme raspadanja bilo je produljeno kada se povećao udio natrijevog škrobnog glikolata u tabletama. To je pripisano stvaranju viskoznog sloja gela oko tableta, što nije primijećeno u pripravi tableta s natrijevom soli kroskarmeloze i krospovidonom. Oslobađanje meloksikama bilo je brzo iz svih tableta, osim iz tableta s visokim udjelom natrijeve soli škrobnog glikolata. Kompleksiranje meloksikama s β-CD značajno je povećalo topljivost lijeka i poboljšalo mehanička svojstva tableta

Non-Hermitian Delocalization and Eigenfunctions

Recent literature on delocalization in non-Hermitian systems has stressed criteria based on sensitivity of eigenvalues to boundary conditions and the existence of a non-zero current. We emphasize here that delocalization also shows up clearly in eigenfunctions, provided one studies the product of left- and right-eigenfunctions, as required on physical grounds, and not simply the squared modulii of the eigenfunctions themselves. We also discuss the right- and left-eigenfunctions of the ground state in the delocalized regime and suggest that the behavior of these functions, when considered separately, may be viewed as ``intermediate'' between localized and delocalized.Comment: 8 pages, 11 figures include

Vortex Flow and Transverse Flux Screening at the Bose Glass Transition

We investigate the vortex phase diagram in untwinned YBaCuO single crystals with columnar defects. These randomly distributed defects, produced by heavy ion irradiation, are expected to induce a ``Bose Glass'' phase of localized vortices characterized by a vanishing resistance and a Meissner effect for magnetic fields transverse to the defect axis. We directly observe the transverse Meissner effect using an array of Hall probe magnetometers. As predicted, the Meissner state breaks down at temperatures Ts that decrease linearly with increasing transverse magnetic field. However, Ts falls well below the conventional melting temperature Tm determined by a vanishing resistivity, suggesting an intermediate regime where flux lines are effectively localized even when rotated off the columnar defects.Comment: 15 pages, 5 figure

Modeling a teacher in a tutorial-like system using Learning Automata

The goal of this paper is to present a novel approach to model the behavior of a Teacher in a Tutorial- like system. In this model, the Teacher is capable of presenting teaching material from a Socratic-type Domain model via multiple-choice questions. Since this knowledge is stored in the Domain model in chapters with different levels of complexity, the Teacher is able to present learning material of varying degrees of difficulty to the Students. In our model, we propose that the Teacher will be able to assist the Students to learn the more difficult material. In order to achieve this, he provides them with hints that are relative to the difficulty of the learning material presented. This enables the Students to cope with the process of handling more complex knowledge, and to be able to learn it appropriately. To our knowledge, the findings of this study are novel to the field of intelligent adaptation using Learning Automata (LA). The novelty lies in the fact that the learning system has a strategy by which it can deal with increasingly more complex/difficult Environments (or domains from which the learning as to be achieved). In our approach, the convergence of the Student models (represented by LA) is driven not only by the response of the Environment (Teacher), but also by the hints that are provided by the latter. Our proposed Teacher model has been tested against different benchmark Environments, and the results of these simulations have demonstrated the salient aspects of our model. The main conclusion is that Normal and Below-Normal learners benefited significantly from the hints provided by the Teacher, while the benefits to (brilliant) Fast learners were marginal. This seems to be in-line with our subjective understanding of the behavior of real-life Students

Apocrine Hidradenocarcinoma of the Scalp: A Classification Conundrum

Introduction The classification of malignant sweat gland lesions is complex. Traditionally, cutaneous sweat gland tumors have been classified by either eccrine or apocrine features. Methods A case report of a 33-year-old Hispanic man with a left scalp mass diagnosed as a malignancy of adnexal origin preoperatively is discussed. After presentation at our multidisciplinary tumor board, excision with ipsilateral neck dissection was undertaken. Results Final pathology revealed an apocrine hidradenocarcinoma. The classification and behavior of this entity are discussed in this report. Conclusion Apocrine hidradenocarcinoma can be viewed as an aggressive malignant lesion of cutaneous sweat glands on a spectrum that involves both eccrine and apoeccrine lesions

iButton Enrolment and Verification Requirements for the Pressure Sequence Smartcard Biometric

With the growing number of smartcard applications there comes an increasing need to restrict access to the card itself. In previous work we proposed the pressure sequence biometric, within which a biometric sensor is integrated onto the card in a low-cost and mechanically compliant manner. Using an off-card verifier we demonstrated reasonable discrimination between users. In this paper we consider a number of on-card verification schemes, the best of which offers an equal error rate of 2.3%. On-card computational time requirements were found to be 3.1 seconds for enrolment and 0.12 seconds for verification. Incorporating our implementation into an existing applet used 684 bytes of program space. Whilst data memory requirements are estimated to be 1400 and 300 bytes for enrolment and verification, respectively. These time and size requirements demonstrate our biometric as a practical proposition for the protection of smart cards. Experiments were performed with the iButton's Java Card platform