Water management considerations at a dam site

The Akaki Dam is located some 26 km southwest of Nicosia and 0.5 km west of Malounta village. The dam is up to 31 m high and has a storage capacity of 2 million m³. The reservoir retained by the dam has a surface area of 18 ha at full storage levels. The paper discusses water management considerations for the area following the construction of the dam.     

Experimental Analysis of an SSL-Based AKA Mechanism in 3G-and-Beyond Wireless Networks

The SSL/TLS protocol is a de-facto standard that has proved its effectiveness in the wired Internet and it will probably be the most promising candidate for future heterogeneous wireless environments. In this paper, we propose potential solutions that this protocol can offer to future “all-IP” heterogeneous mobile networks with particular emphasis on the user's side. Our approach takes into consideration the necessary underlying public key infrastructure (PKI) to be incorporated in future 3G core network versions and is under investigation by 3GPP. We focus on the standard 3G+ authentication and key agreement (AKA), as well as the recently standardized extensible authentication protocol (EAP)-AKA procedures and claim that SSL-based AKA mechanisms can provide for an alternative, more robust, flexible and scalable security framework. In this 3G+ environment, we perceive authentication as a service, which has to be performed at the higher protocol layers irrespectively of the underlying network technology. We conducted a plethora of experiments concentrating on the SSL's handshake protocol performance, as this protocol contains demanding public key operations, which are considered heavy for mobile devices. We gathered measurements over the GPRS and IEEE802.11b networks, using prototype implementations, different test beds and considering battery consumption. The results showed that the expected high data rates on one hand, and protocol optimisations on the other hand, can make SSL-based authentication a realistic solution in terms of service time for future mobile systems.     

An analytic network process and trapezoidal interval‐valued fuzzy technique for order preference by similarity to ideal solution network access selection method

Next generation wireless networks consist of many heterogeneous access technologies that should support various service types with different quality of service (QoS) constraints, as well as user, requirements and provider policies. Therefore, the need for network selection mechanisms that consider multiple factors must be addressed. In this paper, a network selection method is proposed by applying the analytic network process to estimate the weights of the selection criteria, as well as a fuzzy version of technique for order preference by similarity to ideal solution to perform the ranking of network alternatives. The method is applied to a heterogeneous network environment providing different QoS classes and policy characteristics. Each user applies the method to select the most appropriate network, which satisfies his or her requirements in respect of his or her service‐level agreement (SLA). Performance evaluation shows that when the user requests only one service, the proposed method performs better compared to the original technique for order preference by similarity to ideal solution, as well as the Fuzzy AHP‐ELECTRE method. Moreover, the proposed method can be applied in cases where a user requires multiple services simultaneously on a device. The sensitivity analysis of the proposed method shows that it can be properly adjusted to conform to network environment changes. Copyright © 2014 John Wiley & Sons, Ltd.     

Multihomogeneous resultant formulae for systems with scaled support

Constructive methods for matrices of multihomogeneous (or multigraded) resultants for unmixed systems have been studied by Weyman, Zelevinsky, Sturmfels, Dickenstein and Emiris. We generalize these constructions to mixed systems, whose Newton polytopes are scaled copies of one polytope, thus taking a step towards systems with arbitrary supports. First, we specify matrices whose determinant equals the resultant and characterize the systems that admit such formulae. Bézout-type determinantal formulae do not exist, but we describe all possible Sylvester-type and hybrid formulae. We establish tight bounds for all corresponding degree vectors, and specify domains that will surely contain such vectors; the latter are new even for the unmixed case. Second, we make use of multiplication tables and strong duality theory to specify resultant matrices explicitly, for a general scaled system, thus including unmixed systems. The encountered matrices are classified; these include a new type of Sylvester-type matrix as well as Bézout-type matrices, known as partial Bezoutians. Our public-domain Maple implementation includes efficient storage of complexes in memory, and construction of resultant matrices.     

On the infeasibility of modeling polymorphic shellcode

Current trends demonstrate an increasing use of polymorphism by attackers to disguise their exploits. The ability for malicious code to be easily, and automatically, transformed into semantically equivalent variants frustrates attempts to construct simple, easily verifiable representations for use in security sensors. In this paper, we present a quantitative analysis of the strengths and limitations of shellcode polymorphism, and describe the impact that these techniques have in the context of learning-based IDS systems. Our examination focuses on dual problems: shellcode encryption-based evasion methods and targeted “blending” attacks. Both techniques are currently being used in the wild, allowing real exploits to evade IDS sensors. This paper provides metrics to measure the effectiveness of modern polymorphic engines and provide insights into their designs. We describe methods to evade statistics-based IDS sensors and present suggestions on how to defend against them. Our experimental results illustrate that the challenge of modeling self-modifying shellcode by signature-based methods, and certain classes of statistical models, is likely an intractable problem.     

Regeneration of Aged Commercial Three-Way Catalysts Using CI-Containing Reagents

The present work is focused on applying washing treatments using Cl-containing reagents, such as di-chloroacetic acid (DCA) for the first time, and 1,2-di-chloropropane, DCP (0.1 M) solutions in regaining the activity and oxygen storage capacity (OSC) of an aged commercial Pd-based TWC. Segments extracted from an aged (56,000 km) commercial Pd/Rh-based (9:1) TWC after washing with DCA resulted in 100 % removal of Pb and about 43 % of P, while washing with DCP solution was ineffective in removing these specific contaminants. DCA-washing regeneration method was found to increase Pd surface concentration by four times compared to the aged TWC, whereas DCP-washing was considerably less effective than DCA in recovering Pd active sites. The OSC of the aged catalyst was significantly improved by the use of DCA-washing, whereas no improvement was observed by DCP-washing. Nevertheless, DCP-washing was found to be more effective in improving the performance of aged TWC towards CO oxidation. The removal of Pb is likely a reason for the DCA-washing being more effective in improving C₃H₆ and NO conversions and OSC.     

Discrimination between fortuitous and biologically constrained open reading frames in DNA sequences of Saccharomyces cerevisiae

The systematic sequencing of the yeast genome has raised the problem of the biological significance of the open reading frames (ORFs) revealed: it is possible that some of these are fortuitous. To avoid the analysis of such fortuitous ORFs, a minimum length of 100 sense codons was adopted. Nevertheless, the presence of fortuitous ORFs of more than 100 codons cannot be excluded. Thus, in the context of functional analysis, a method for discrimination between fortuitous and biologically active ORFs may be useful. The discrimination method described here is based on multiple criteria: ORF length, codon bias, and both amino-acid and dipeptide composition of the corresponding polypeptide. The thresholds for each criterion are based on the comparison between two learning sets: one drawn from random DNA sequences and the second from known genes. The method was validated by two test sets (one random and one biological) and then applied to the ORFs of chromosomes I, II, III, V, VIII, IX and XI. This method predicts 123 fortuitous ORFs among the 1773 identified on these chromosomes.     

Automatic intron detection in nuclear DNA sequences of Saccharomyces cerevisiae

The goal of the present work is the construction of software (EXPLORA) which automatically detects Open Reading Frames (ORF), intron-containing or not, in the nuclear sequences of the yeast Saccharomyces cerevisiae. In order to detect introns within (or preceding) ORFs, one must define precise rules of how an intron is identified. These rules are described here. The software is able to detect correctly an intron-associated ORF in at least 88% of cases. We tested all yeast nuclear entries of the EMBL database with the software, and found, in addition to the known intron-associated ORFs, some others which may include an intron. Finally the software was applied to the DNA sequences of chromosomes III and XI, in which it detected eight new intron-associated ORFs.