2,696 research outputs found
Optimal Timing in Dynamic and Robust Attacker Engagement During Advanced Persistent Threats
Advanced persistent threats (APTs) are stealthy attacks which make use of
social engineering and deception to give adversaries insider access to
networked systems. Against APTs, active defense technologies aim to create and
exploit information asymmetry for defenders. In this paper, we study a scenario
in which a powerful defender uses honeynets for active defense in order to
observe an attacker who has penetrated the network. Rather than immediately
eject the attacker, the defender may elect to gather information. We introduce
an undiscounted, infinite-horizon Markov decision process on a continuous state
space in order to model the defender's problem. We find a threshold of
information that the defender should gather about the attacker before ejecting
him. Then we study the robustness of this policy using a Stackelberg game.
Finally, we simulate the policy for a conceptual network. Our results provide a
quantitative foundation for studying optimal timing for attacker engagement in
network defense.Comment: Submitted to the 2019 Intl. Symp. Modeling and Optimization in
Mobile, Ad Hoc, and Wireless Nets. (WiOpt
Identification of genic moss SSR markers and a comparative analysis of twenty-four algal and plant gene indices reveal species-specific rather than group-specific characteristics of microsatellites
BACKGROUND: The moss Physcomitrella patens is an emerging model in comparative plant science. At present, the Physcomitrella genome is sequenced at the Joint Genome Institute (USA). In this study we present our results on the development of expressed sequence tag-derived microsatellite markers for Physcomitrella patens, their classification and applicability as genetic markers on the intra- as well as on the interspecies level. We experienced severe restrictions to compare our results on Physcomitrella with earlier studies for other plant species due to varying microsatellite search criteria and a limited selection of analysed species. As a consequence, we performed a side by side analysis of expressed sequence tag-derived microsatellites among 24 plant species covering a broad phylogenetic range and present our results on the observed frequencies. RESULTS: We identified 3,723 microsatellites using the software MISA in a non-redundant Physcomitrella expressed sequence tag database comprising more than 37 megabases of nucleotide information. For 2,951 microsatellites appendant primer sequences have been derived. PCR of 376 microsatellites yielded 88 % successful amplicons and over 30 % polymorphisms between two Physcomitrella accessions. The polymorphism information content of 64 microsatellites based on 21 different Physcomitrella accessions was comparably high with a mean of 0.47 +/- 0.17. Of the 64 Physcomitrella microsatellite markers, 34 % respectively 79.7 % revealed cross-species applicability in two closely related moss species. In our survey of two green algae, two mosses, a fern, a fern palm, the ginkgo tree, two conifers, ten dicots and five monocots we detected an up to sevenfold variation in the overall frequency with a minimum of 37 up to maximal 258 microsatellites per megabase and a high variability among the different microsatellite class and motif frequencies. Numerous species-specific microsatellite frequencies became evident and several deviations to earlier reports were ascertained. CONCLUSION: With the Physcomitrella microsatellite marker set a valuable tool has been made available for further genetic and genomic applications on the intra- as well as on the interspecies level. The comparative survey of expressed sequence tag-derived microsatellites among the plant kingdom is well suited for a classification of future studies on plant microsatellites
Erinnerungsblätter an die Feier des 50-jährigen Jubiläums der Stackelbergschen Familienstiftung
http://www.ester.ee/record=b3889944*es
Lifestyle and risk of abdominal aortic aneurysm
Background
Lifestyle-related factors associated with abdominal aortic aneurysm (AAA) disease are very scarcely investigated in prospective design. Identification of such could provide better understanding of AAA epidemiology and etiology, and provide new hypotheses for studies on AAA growth rate in order to try to limit progression of the disease. The overall aim of this thesis was to study possible associations between modifiable, lifestyle-related factors and risk of AAA.
Methods and Results
Two prospective population-based cohorts of 84,890 middle-aged and elderly men
and women, from Central Sweden (the Cohort of Swedish Men and the Swedish Mammography Cohort) constituted the study population for all studies in this thesis. In Study I-IV, AAA diagnosis and/or repair was identified over the 12- to 14-year follow-up in the Swedish National Patient Register, the Swedish Cause of Death Register, and the National Register for Vascular Surgery (Swedvasc). In Study V, abdominal aortic diameter (AAD) was assessed in 14,249 men screened for AAA (AAD ≥30 mm) between 65 and 75 years of age (mean 13 years after baseline, 1 January 1998). Linear regression models were used to estimate mean AAD, and Cox proportional hazards regression models were used to estimate hazard ratios (HR) of AAA as a measure of AAA risk, by comorbidities and self-reported lifestyle-related exposures, with corresponding 95% confidence intervals (CI’s).
We observed that smoking was associated with an increased risk of AAA, and with an increased mean AAD among men. Across all specific smoking strata, the absolute risks of AAA were higher among men, while the relative risks seemed to be more pronounced among women. The AAA incidence was higher among smoking women than among never smoking men. Following smoking cessation, women had a more rapid decline in excess risk associated with current smoking than men did. Furthermore, obesity seemed to be associated with an increased AAA risk; central obesity (i.e. increased waist circumference) was associated with AAA diagnosis and/or repair, while total obesity (i.e. increased BMI) was associated with screening detected AAA, and with a larger mean AAD, among men.
We also observed that consumption of fruits, but not vegetables, was associated with a decreased risk of AAA, an association that seemed to be more pronounced with ruptured AAA than with intact AAA. No association was observed between a healthy diet in general and risk of AAA detected at screening among men. A moderate consumption of total alcohol (i.e. ethanol) was associated with a lower risk of AAA diagnosis and/or repair, but not among participants free from cardiovascular disease (CVD). Alcohol consumption was also associated with a smaller mean AAD among men. The most commonly consumed alcoholic beverages – beer among men and wine among women – were inversely associated with AAA diagnosis and/or repair, whereas no association was observed for spirits.
Last, when compared with those who almost never walked/bicycled, men who were walking/bicycling >40 min/day had a lower risk of having an AAA at screening. Among men, CVD was associated with a larger predicted mean AAD, and with an increased risk of AAA detected at screening.
Conclusions
Lifestyle-related exposures were prospectively associated with AAA disease, and with mean AAD. Regarding risk of AAA, current smoking may affect women to a greater extent than men, obesity may increase the risk, and consumption of fruits, a moderate consumption of alcohol, and physical activity, may reduce the risk
Detecting Data-Flow Errors in BPMN 2.0
Data-flow errors in BPMN 2.0 process models, such as missing or unused data, lead to undesired process executions. In particular, since BPMN 2.0 with a standardized execution semantics allows specifying alternatives for data as well as optional data, identifying missing or unused data systematically is difficult. In this paper, we propose an approach for detecting data-flow errors in BPMN 2.0 process models. We formalize BPMN process models by mapping them to Petri Nets and unfolding the execution semantics regarding data. We define a set of anti-patterns representing data-flow errors of BPMN 2.0 process models. By employing the anti-patterns, our tool performs model checking for the unfolded Petri Nets. The evaluation shows that it detects all data-flow errors identified by hand, and so improves process quality
Detecting Data-Flow Errors in BPMN 2.0
Data-flow errors in BPMN 2.0 process models, such as missing or unused data, lead to undesired process executions. In particular, since BPMN 2.0 with a standardized execution semantics allows specifying alternatives for data as well as optional data, identifying missing or unused data systematically is difficult. In this paper, we propose an approach for detecting data-flow errors in BPMN 2.0 process models. We formalize BPMN process models by mapping them to Petri Nets and unfolding the execution semantics regarding data. We define a set of anti-patterns representing data-flow errors of BPMN 2.0 process models. By employing the anti-patterns, our tool performs model checking for the unfolded Petri Nets. The evaluation shows that it detects all data-flow errors identified by hand, and so improves process quality
Der bankmässig organisierte Agrarkredit in Estland : akademische Abhandlung
http://www.ester.ee/record=b4003996*es
Lalli, Scarron et les Mazarinades – Parodie et réalisme dans la littérature française au milieu du XVIIe siècle
Comme chacun sait, le roman est aujourd’hui «la chose du monde la mieux partagée». Les non-spécialistes le prennent pour un équivalent de littérature, les spécialistes s’occupent aussi volontiers des autres genres littéraires. Mais le roman a ceci de particulier que son histoire paraît être exemplaire: c’est le genre qui démontre le plus ostensiblement qu’après des débuts idéalistes, la littérature finit par devenir réaliste. Ce n’est pas un hazard que quand nous parlons de réalisme en littér..
standard and innovation
Die akute lymphoblastische Leukämie im Kindesalter hat mit heutigen Methoden
eine Heilungsrate von über 90%. Dagegen überleben nur etwa 50% der Kinder mit
Rückfall einer ALL trotz intensiver Chemotherapie und HSZT bei den meisten
Patienten. Somit besteht bei Kindern mit ALL-Rezidiv ein dringender Bedarf für
die weitere Optimierung der Standardtherapie, der besseren Charakterisierung
von biologischen und prognostischen Subgruppen sowie für neue Medikamente mit
anderen idealerweise gezielteren Wirkmechanismen, die in der Lage sind,
Therapieresistenz der leukämischen Klone zu durchbrechen. Die ALL-REZ BFM
Studiengruppe hat seit nunmehr 30 Jahren Therapieoptimierungsstudien
durchgeführt und damit die Prognose der Kinder mit ALL-Rezidiv konsequent
verbessert. Dabei wurde insbesondere die Dosierung und der Verabreichungsmodus
von hoch dosiertem Methotrexat in prospektiven randomisierten Studien
untersucht, wobei in der Studie ALL-REZ BFM 90 die Dosis von 1g/m² mit einer
Infusionsdauer von 36 und einer reduzierten Leukovorin Rescue als optimales
Konzept etabliert werden konnten. Neben den randomisierten Fragen konnte diese
Studie eine Reihe weiterer Erkenntnisse über die biologische Charakteristik
der Erkrankung, prognostische Faktoren und Therapieverbesserungen im
historischen Vergleich erarbeiten. Die intensive Chemotherapie und die
allogene hämatopoetische Stammzelltransplantation ist verbunden mit akuten
Nebenwirkungen und Spätfolgen zu denen auch das Auftreten von Zweitmalignomen
gehört. Im Verlauf der ALL-REZ BFM Studien konnten Patientengruppen definiert
werden, die eine besonders schlechte Prognose haben und mit konventioneller
Therapie nicht heilbar sind. Zu diesen zählen Patienten mit Rezidiv von
lymphoblastischen Lymphomen, sowie Patienten mit Nonresponse auf die
konventionelle Rezidiv- Induktionstherapie. Innovative diagnostische Verfahren
erlauben darüber hinaus, weitere Patientengruppen zu definieren, die ein hohes
Folgerezidivrisiko trotz intensiver konventioneller Therapie haben. Dazu zählt
die Quantifizierung minimaler Resterkrankung im Therapieverlauf durch
molekularbiologische Methoden. Insbesondere Patienten mit einer hohen
minimalen Resterkrankung vor allogener hämatopoetischer
Stammzelltransplantation haben ein hohes Risiko für ein erneutes ALL-Rezidiv
mit dann infauster Prognose. Die so definierten Patientengruppen haben neben
solchen mit Folgerezidiv einer ALL einen dringenden Bedarf für die Einführung
von neuen Substanzen mit anderen Wirkmechanismen als die der konventionellen
Chemotherapie und idealerweise mit gezielter leukämiespezifischer Aktivität
und geringeren akuten und langfristigen Nebenwirkungen. Die ALL-REZ BFM
Studiengruppe beteiligt sich an einem Programm zur Entwicklung von neuen
Substanzen bei ALL im Kindesalter, das eine enge Interaktion mit den
zuständigen Behörden, der pharmazeutischen Industrie und den involvierten
akademischen Gruppen erfordert. Die zukünftigen Strategien zur Behandlung von
Kindern mit rezidivierter und/oder refraktärer ALL werden in einem durch die
EU finanziertes Projekt international harmonisiert und erlauben die
Durchführung von prospektiven randomisierten Studien in biologischen
Subgruppen, um neue Substanzen nach erfolgreichen Phase I/II Studien in
kurative Therapiekonzepte integrieren zu können. Die aus dieser Entwicklung
erwachsene Vision ist eine nebenwirkungsarme gezielte und individualisierte
Behandlung von Kindern mit ALL mit möglichst vollständiger Vermeidung von
Rückfällen der Erkrankung.Today’s cure rates of childhood acute lymphoblastic leukemia (ALL) have
exceeded 90%. In contrast, only 50% of children with relapsed ALL survive
despite intensive chemotherapy and allogeneic hematopoietic stem-cell
Transplantation (HSCT) in most patients. Thus, there is an urgent need for
optimization of standard therapy in childhood relapsed ALL, for a better
characterization of biologic and prognostic subgroups, and for new drugs with
ideally targeted mechanism of action allowing for overcoming treatment
resistance of leukemic clones. The ALL-REZ BFM Study Group has conducted
clinical trials for optimization of treatment since 30 years and subsequently
improved the prognosis of children with relapsed ALL. In particular the dose
and mode of application of high dose methotrexate has been investigated in
randomized prospective trials. Furthermore, improvement of therapy has been
achieved with uncontrolled changes referring to historical controls. Intensive
chemotherapy and allogeneic HSCT is associated with acute and late toxicities
one of which is secondary malignancy. In the course of the ALL-REZ BFM trials
patient subgroups could be defined with a very poor prognosis and without
chance of cure with conventional therapies. These include patient with relapse
of a lymphoblastic lymphoma and those with nonresponse to conventional salvage
induction therapy. The quantification of minimal residual disease (MRD) with
molecular biologic techniques allow defining additional patient groups with
very high risk for subsequent relapse despite intensive conventional
treatment. Those patients with high MRD pre allogeneic HSCT have a high risk
of relapse post HSCT with then dismal prognosis. These patient groups have an
urgent need for the introduction of new drugs with targeted mechanism of
action and less acute and late side effects. The ALL-REZ BFM Study Group joins
activities to develop such new agents in close collaboration with industry and
competent authorities. Future strategies for treatment of childhood relapsed
ALL in Europe are harmonized in an EU funded FP7 project allowing for
performing large prospective randomized trials in biologic subgroups to
integrate new agents after successfully passing phase I/II trials in curative
treatment protocols. The vision for the future is a low-toxic individualized
treatment for children with ALL with prevention of relapse of the disease
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