A goal-based modeling approach to develop security requirements of fault tolerant security-critical systems

Large amount of (security) faults existing in software systems could be complex and hard to identify during the fault analysis. So, it is not always possible to fully mitigate the internal or external security faults (vulnerabilities or threats) within the system. On the other hand, existence of faults in the system may eventually lead to a security failure. To avoid security failure of the target system we need to make it flexible and tolerant in the presence of security faults. This paper introduces a goal-based modeling approach to develop security requirements of security-critical systems (SCSs) by explicitly factoring the faults into the requirement engineering process. Our approach establishes a model for security requirements (SRM) with respect to the formally described model of security faults (SFM). We care for fault tolerance in SRM by taking into consideration partial satisfaction of security goals. The proposed approach factors this partiality into the goals by applying proper mitigation techniques during the refinement process. This eventually contributes to a fault tolerant model for security requirements of the target system

Taxonomic revision, molecular phylogeny and zoogeography of the huntsman spider genus Eusparassus (Araneae: Sparassidae)

The spider genus Eusparassus Simon, 1903 (Araneae: Sparassidae: Eusparassinae; stone huntsman spider) is revised worldwide to include 30 valid species distributed exclusively in Africa and Eurasia. The type species E. dufouri Simon, 1932 is redescribed and a neotype is designated from Portugal. An extended diagnosis for the genus is presented. Eight new species are described: Eusparassus arabicus Moradmand, 2013 (male, female) from Arabian Peninsula, E. educatus Moradmand, 2013 (male, female) from Namibia, E. reverentia Moradmand, 2013 (male, female) from Burkina Faso and Nigeria, E. jaegeri Moradmand, 2013 (male, female) from South Africa and Botswana, E. jocquei Moradmand, 2013 (male, female) from Zimbabwe, E. borakalalo Moradmand, 2013 (female) from South Africa, E. schoemanae Moradmand, 2013 (male, female) from South Africa and Namibia and E. mesopotamicus Moradmand and Jäger, 2012 (male and female) from Iraq, Iran and Turkey. 22 species are re-described six of them are transferred from the genus Olios Walckenaer, 1837. Six species-groups are proposed: the dufouri-group [8 species: E. dufouri, E. levantinus Urones, 2006, E. barbarus (Lucas, 1846), E. atlanticus Simon, 1909, E. syrticus Simon, 1909, E. oraniensis (Lucas, 1846), E. letourneuxi (Simon, 1874), E. fritschi (Koch, 1873); Iberian Peninsula to parts of north-western Africa], walckenaeri-group [3 species: E. walckenaeri (Audouin, 1826), E. laevatus (Simon, 1897), E. arabicus; eastern Mediterranean to Arabia and parts of north-eastern Africa], doriae-group [7 species: E. doriae (Simon, 1874), E. kronebergi Denis, 1958, E. maynardi (Pocock, 1901), E. potanini (Simon, 1895), E. fuscimanus Denis, 1958, E. oculatus (Kroneberg, 1846) and E. mesopotamicus; Middle East to Central and South Asia], vestigator-group (3 species: E. vestigator (Simon, 1897), E. reverentia, E. pearsoni (Pocock, 1901); central to eastern Africa and an isolated area in NW India], jaegeri-group [4 species: E. jaegeri, E. jocquei, E. borakalalo, E. schoemanae; southern and south-eastern Africa], tuckeri-group [2 species: E. tuckeri (Lawrence, 1927), E. educatus; south-western Africa). Two species, E. pontii Caporiacco, 1935 and E. xerxes (Pocock, 1901) cannot be placed in any of the above groups. Two species are transferred from Eusparassus to Olios: O. flavovittatus (Caporiacco, 1935) and O. quesitio Moradmand, 2013. 14 species are recognized as misplaced in Eusparassus, thus nearly half of the described species prior to this revision were placed mistakenly in this genus. Neotypes are designated for E. walckenaeri from Egypt, E. barbarus, E. oraniensis and E. letourneuxi (all three from Algeria) to establish their identity. The male and female of Cercetius perezi Simon, 1902, which was known only from the immature holotype, are described for the first time. It is recognized that the monotypic and little used generic name Cercetius Simon, 1902 — a species, which had been known only from the immature holotype — as a synonym of the widely used name Eusparassus. The case proposal 3596 (conservation of name Eusparassus) is under consideration by ICZN. The first comprehensive molecular phylogeny of the family Sparassidae with focus on the genus Eusparassus is investigated using four molecular markers (mitochondrial COI and 16S; nuclear H3 and 28S). The monophyly of Eusparassus and the dufouri, walckenaeri and doriae species-groups are recovered with the latter two groups more closely related. The monophyly of the tuckeri-group is not supported and the position of E. jaegeri as the only available member of the jaegeri-group is not resolved within the Eusparassus clade. DNA samples of the vestigator-group were not accessible for this study. The origination of the genus Eusparassus around 70 million years ago (MA) is estimated according to molecular clock analyses. Using this recent result in combination with some biogeographic and geological data, the Namib Desert is proposed as the place of ancestral origin for Eusparassus and putative Eusparassinae genera. Further analyses are done on the phylogenetic relationships of Sparassidae and its subfamilies. The Eusparassinae are not confirmed as monophyletic, with the two original genera Eusparassus and Pseudomicrommata in separate clades and only the latter clusters with most other assumed Eusparassinae, here termed the "African clade". Monophyly of the subfamilies Sparianthinae, Heteropodinae sensu stricto, Palystinae and Deleninae is recovered. The Sparianthinae are supported as the most basal clade, diverging considerably early (143 MA) from all other Sparassidae. The Sparassinae and genus Olios are found to be polyphyletic. The Sparassidae are confirmed as monophyletic and as most basal group within the RTA-clade. The divergence time of Sparassidae from the RTA-clade is estimated with 186 MA in the Jurassic. No affiliation of Sparassidae to other members of the "Laterigradae" (Philodromidae, Selenopidae and Thomisidae) is observed, thus the crab-like posture of this group was proposed a result of convergent evolution. Only the families Philodromidae and Selenopidae are found members of a supported clade. Including a considerable amount of RTA-clade representatives, the higher-level clade Dionycha is not but monophyly of the RTA-clade itself is supported

Cloning of the xylanase gene from soil Streptomyces into Escherichia coli for the poultry industry application

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗStreptomyces are gram-positive aerobic strains that are isolated from soil, water, sediments, and various sources. The bacteria are capable of producing secondary metabolites, such as enzymes that sometimes play unique functional roles in industry, and are one of the important bio-control agents. This study aimed to isolate and clone thexylanase gene from soil Streptomyces. Soil samples were collected from Markazi Province, Iranafter specific biochemical examinations, isolation of bacteria, and DNA extraction. PCR was then performed to identify the strains containing the xylanase gene. The gene from the positive strains was cloned into an E.coli host-vector by TA cloning technique and finally, the expression of genes in E. coli origami was measured by Real-Time PCR technique. ClustalX and Mega5 software were used to draw the phylogenetic tree. A total of twelve Streptomyces isolates were identified from the soil samples. Among all the isolates, threeones had the xylanase gene. After cloning the xylanase genes, the cloned strains were isolated. To confirm the DNA cloning, Real-Time PCR was performed, and finally, the PCR product where sequenced. In this study, Streptomyces was identified as a native strain for the expression of xylanase after generating recombinant plasmid and TA cloning. It can be stated that cloning of the xylanase gene from soil Streptomyces in E. coli can be used in the poultry industry

Unambiguous observation of F-atom core-hole localization in CF4 through body-frame photoelectron angular distributions

Citation: McCurdy, C. W., Rescigno, T. N., Trevisan, C. S., Lucchese, R. R., Gaire, B., Menssen, A., . . . Weber, T. (2017). Unambiguous observation of F-atom core-hole localization in CF4 through body-frame photoelectron angular distributions. Physical Review A, 95(1). doi:10.1103/PhysRevA.95.011401A dramatic symmetry breaking in K-shell photoionization of the CF4 molecule in which a core-hole vacancy is created in one of four equivalent fluorine atoms is displayed in the molecular frame angular distribution of the photoelectrons. Observing the photoejected electron in coincidence with an F+ atomic ion after Auger decay is shown to select the dissociation path where the core hole was localized almost exclusively on that atom. A combination of measurements and ab initio calculations of the photoelectron angular distribution in the frame of the recoiling CF3+ and F+ atoms elucidates the underlying physics that derives from the Ne-like valence structure of the F(1s-1) core-excited atom. © 2017 American Physical Society

Hydrogen and fluorine migration in photo-double-ionization of 1,1-difluoroethylene (1,1-C2H2F2) near and above threshold

We have studied the nondissociative and dissociative photo-double-ionization of 1,1-difluoroethylene using single photons of energies ranging from 40 to 70 eV. Applying a coincident electron-ion three-dimensional momentum imaging technique, kinematically complete measurements have been achieved. We present the branching ratios of the six reaction channels identified in the experiment. Electron-ion energy maps and relative electron emission angles are used to distinguish between direct and indirect photo-double-ionization mechanisms at a few different photon energies. The influence of selection and propensity rules is discussed. Threshold energies of double ionization are extracted from the sum of the kinetic energies of the electrons, which hint to the involvement of different manifolds of states. The dissociative ionization channels with two ionic fragments are explored in detail by measuring the kinetic energy release of the fragment ions, sum of the kinetic energies, as well as the energy sharing of the two emitted electrons. We investigate the migration of hydrogen and fluorine atoms and compare the experimental results to the photo-double-ionization of centrosymmetric linear and planar hydrocarbons (C[subscript 2]H[subscript 2] and C[subscript 2]H[subscript 4]) whenever possible

CPU Utilization Improvement of Multiple-Core Processors Through Cache Management and Task Scheduling

RÉSUMÉ De nos jours, les architectures multicœurs et multiprocesseurs sont largement utilisées dans les centres de données. Une telle utilisation fournit les performances requises pour diverses tâches, telles que le C-RAN(accès radio par info-nuagique). Le traitement du signal sans fil en bande de base(wireless baseband) pour les normes 4G et 5G désigne un ensemble de tâches qui doivent être exécutées dans un intervalle de temps spécifique. Par exemple, la pile de liaison montante(up-link stack) pour une station de base 4G virtualisée a été décomposée en plus de 1000 tâches exécutables en 5 ms. Avec la 5G, la latence cible dans un scénario de bout en bout avec utilisation à latence très faible(ultra-low latency) est de 1 ms, tandis que la complexité de calcul est d’un à deux ordres de grandeur plus élevée que celle de la 4G. Le défi à surmonter c’est de répondre à ces objectifs en terme de complexité de traitement. Pour ce faire, il est crucial de caractériser la variabilité du temps de traitement par rapport aux caractéristiques du modèle de mémoire afin de garantir un temps de traitement donné dans les grappes d’ordinateurs classiques.En outre, la planification des tâches sur les systèmes multicœurs reste un problème ouvert. Un tel problème doit être analysé afin d’utiliser pleinement la capacité de traitement d’un système multicoeur d’un système multicoeur et d’atteindre une faible latence. Afin de remédier à l’utilisation ineÿcace des cœurs de processeur, un schéma d’ordonnancement des tâches basé sur la mise en file d’attente, qui se focalise sur le calcul parallèle local, est proposé. Dans cette mémoire, on introduit la gestion multi-files pour la planification dynamique des tâches afin de cibler une utilisation complète à 100% des cœurs de CPU locaux pour des tâches d’entrée suÿsantes. Plusieurs simulations sont faites pour vérifier le schéma de planification des tâches proposé. Les résultats rapportés confirment sa viabilité et son efficacité. De plus, l’utilisation de la mémoire cache est l’une des principales sources de variabilité du temps d’exécution. En outre, une gestion ineÿcace de la mémoire cache s’avère probléma-tique dans les systèmes avec WCET. Une approche eÿcace de gestion de la cache doit prendre en compte simultanément la planification des tâches et la gestion de la cache. L’approche optimale de gestion de la cache oblige de manière critique à prendre en compte les priorités associées à toutes les tâches; la connaissance de ces priorités est essentielle pour détecter et éviter les goulots d’étranglement dans le système.----------ABSTRACT Nowadays, modern multiprocessor and multicore architectures are widely used in data centers. Such usage provides the required performance for a variety of tasks, such as the C-RAN(Cloud-Radio-Access-Network). Wireless baseband signal processing for the 4G and 5G standards designates a range of tasks which must be executed in a specific time slot. For instance, the up-link stack of one 4G virtualized-base station was decomposed in more than 1000 tasks executable within 5ms. In 5G, the expected target latency for ultra-low latency use cases is 1ms in an end-to-end scenario; while the computational complexity is expected to be one to two orders of magnitude higher than that of 4G. It remains to be seen whether and how reaching such computational complexity is feasible. It is a crucial factor to characterize processing time variability besides features of memory model to guarantee a given processing time in mainstream computer clusters.Besides, the task scheduling on multicore systems is still an open issue. Such a problem needs to be analyzed in order to fully utilize the processing capacity and to achieve low processing latency. In order to tackle the inefficient utilization of CPU cores, a queueing-based data-driven task scheduling scheme, which focuses on local parallel computing, is proposed in this thesis. This thesis introduces multi-queue management for dynamic task scheduling to target 100% utilization of local CPU cores for sufficient input tasks. Finally, the thesis entails several simulations to verify the proposed task scheduling scheme. The reported results confirm its viability and efficiency. Moreover, cache memory usage is one of the primary sources of execution time variability. Besides, inefficient management of cache memory proves to be problematic in systems with which WCET(Worst-Case-Execution-Time) is of concern. An efficient cache managing approach needs to take both task scheduling and cache management into account simultaneously. Optimal cache-management imposes considering priorities associating with all tasks; the knowledge of such priorities is essential for detecting and avoiding system bottlenecks. Such approach proposes allocating adequate resources to such a critical task to facilitate better management. The work starts with the introduction of a simple, scalable, and configurable test method called an Array of Counters, the purpose of which is to characterize the processing time variations of multicore architectures. The technique helps to find system bottlenecks. Such help is conducive to a more optimized and enhanced cache-management algorithm

A preliminary molecular phylogeny of the genus Pholcus in Iran, with notes on taxonomy

Iran is a large country with diverse and unique climate and ecology; therefore, it is expected to discover an exceptional fauna with high species diversity by carefully examining the unknown areas. A few taxonomic studies have been so far conducted on the genus Pholcus in Iran. Taxonomic and preliminary phylogenetic evaluation of widespread species of the genus Pholcus from Iran is considered in the present study, based on specimens collected from northern and southwestern parts of the country. A molecular study was undertaken on some representatives of species of the Pholcus phalangioides species-group (cellar spiders) using newly designed primers with 350 bp of partial fragments of mtDNA gene, cytochrome oxidase subunit 1 (COI). These preliminary molecular data in line with morphological identifications using characters related to the copulatory organs presented a total of five distinct clades of Pholcus that four clades were contributed with formerly identified species and one represented a distinct lineage unknown for science

An Afrotropic element at the north-western periphery of the Oriental Region: Pseudomicrommata mokranica sp. nov. (Araneae: Sparassidae)

The surprising discovery of a new species of grass huntsman spider, Pseudomicrommata mokranica sp. nov. (male female), belonging to "the African clade", is reported and described from south-eastern Iran, more than 4000 km away from the nearest recorded locality of the genus in Kenya. Similar vicariant occurrences of other sparassid taxa in Africa and Asia are discussed