Fighting Cheating in P2P-based MMVEs with Disjoint Path Routing

In a P2P-based Massively Multiuser Virtual Environment (MMVE) where nodes cannot be trusted, replicating data on multiple nodes is a possibility to increase the reliability to obtain correct data. Current structured P2P networks mostly place replicas in such a way that queries for the replicas travel along similar paths. A malicious node in the common part of all paths can nullify the security gain of replicated data. We therefore propose to combine radix-based prefix routing with a symmetric replication scheme to gain disjoint paths to each of the replicas

Towards Logical Clocks in P2P-based MMVEs

A crucial requirement for peer-to-peer-based Massively Multiuser Virtual Environments (P2P-based MMVEs) is the accurate and reliable synchronization of actions among the users (processes). To do so, clock synchronization protocols can be used. In this paper we first analyze the usage of standard vector clocks for this purpose and show their deficits (e.g. growing large). Then we present a novel variation of vector clocks – pruned vector clocks – which overcome the deficits of standard vector clocks and are therefore suited for their usage in MMVEs. The basic idea of pruned vector clocks is to prune all entries in a vector clock, which are not relevant at some point in time. We show, that with this approach vector clocks will stay constant in size and still provide the necessarily synchronization among the processes

Pedestrian Counting Based on Piezoelectric Vibration Sensor

Pedestrian counting has attracted much interest of the academic and industry communities for its widespread application in many real-world scenarios. While many recent studies have focused on computer vision-based solutions for the problem, the deployment of cameras brings up concerns about privacy invasion. This paper proposes a novel indoor pedestrian counting approach, based on footstep-induced structural vibration signals with piezoelectric sensors. The approach is privacy-protecting because no audio or video data is acquired. Our approach analyzes the space-differential features from the vibration signals caused by pedestrian footsteps and outputs the number of pedestrians. The proposed approach supports multiple pedestrians walking together with signal mixture. Moreover, it makes no requirement about the number of groups of walking people in the detection area. The experimental results show that the averaged F1-score of our approach is over 0.98, which is better than the vibration signal-based state-of-the-art methods.Peer reviewe

Towards Peer-to-Peer-based Cryptanalysis

Abstract-Modern cryptanalytic algorithms require a large amount of computational power. An approach to cope with this requirement is to distribute these algorithms among many computers and to perform the computation massively parallel. However, existing approaches for distributing cryptanalytic algorithms are based on a client/server or a grid architecture. In this paper we propose the usage of peer-to-peer (P2P) technology for distributed cryptanalytic calculations. Our contribution in this paper is three-fold: We first identify the challenges resulting from this approach and provide a classification of algorithms suited for P2P-based computation. Secondly, we discuss and classify some specific cryptanalytic algorithms and their suitability for such an approach. Finally we provide a new, fully decentralized approach for distributing such computationally intensive jobs. Our design takes special care about scalability and the possible untrustworthy nature of the participating peers

Epigenetic changes in myelofibrosis:Distinct methylation changes in the myeloid compartments and in cases with <i>ASXL1</i> mutations

Abstract This is the first study to compare genome-wide DNA methylation profiles of sorted blood cells from myelofibrosis (MF) patients and healthy controls. We found that differentially methylated CpG sites located to genes involved in ‘cancer’ and ‘embryonic development’ in MF CD34+ cells, in ‘inflammatory disease’ in MF mononuclear cells, and in ‘immunological diseases’ in MF granulocytes. Only few differentially methylated CpG sites were common among the three cell populations. Mutations in the epigenetic regulators ASXL1 (47%) and TET2 (20%) were not associated with a specific DNA methylation pattern using an unsupervised approach. However, in a supervised analysis of ASXL1 mutated versus wild-type cases, differentially methylated CpG sites were enriched in regions marked by histone H3K4me1, histone H3K27me3, and the bivalent histone mark H3K27me3 + H3K4me3 in human CD34+ cells. Hypermethylation of selected CpG sites was confirmed in a separate validation cohort of 30 MF patients by pyrosequencing. Altogether, we show that individual MF cell populations have distinct differentially methylated genes relative to their normal counterparts, which likely contribute to the phenotypic characteristics of MF. Furthermore, differentially methylated CpG sites in ASXL1 mutated MF cases are found in regulatory regions that could be associated with aberrant gene expression of ASXL1 target genes

Genomic Profiling of a Randomized Trial of Interferon-α versus Hydroxyurea in MPN Reveals Mutation-Specific Responses

Although somatic mutations influence the pathogenesis, phenotype, and outcome of myeloproliferative neoplasms (MPNs), little is known about their impact on molecular response to cytoreductive treatment. We performed targeted next-generation sequencing (NGS) on 202 pretreatment samples obtained from patients with MPN enrolled in the DALIAH trial (A Study of Low Dose Interferon Alpha Versus Hydroxyurea in Treatment of Chronic Myeloid Neoplasms; #NCT01387763), a randomized controlled phase 3 clinical trial, and 135 samples obtained after 24 months of therapy with recombinant interferon-alpha (IFNα) or hydroxyurea. The primary aim was to evaluate the association between complete clinicohematologic response (CHR) at 24 months and molecular response through sequential assessment of 120 genes using NGS. Among JAK2-mutated patients treated with IFNα, those with CHR had a greater reduction in the JAK2 variant allele frequency (median, 0.29 to 0.07; P < .0001) compared with those not achieving CHR (median, 0.27 to 0.14; P < .0001). In contrast, the CALR variant allele frequency did not significantly decline in those achieving CHR or in those not achieving CHR. Treatment-emergent mutations in DNMT3A were observed more commonly in patients treated with IFNα compared with hydroxyurea (P = .04). Furthermore, treatment-emergent DNMT3A mutations were significantly enriched in IFNα–treated patients not attaining CHR (P = .02). A mutation in TET2, DNMT3A, or ASXL1 was significantly associated with prior stroke (age-adjusted odds ratio, 5.29; 95% confidence interval, 1.59-17.54; P = .007), as was a mutation in TET2 alone (age-adjusted odds ratio, 3.03; 95% confidence interval, 1.03-9.01; P = .044). At 24 months, we found mutation-specific response patterns to IFNα: (1) JAK2- and CALR-mutated MPN exhibited distinct molecular responses; and (2) DNMT3A-mutated clones/subclones emerged on treatment

Modellgetriebene Entwicklung Dienstgüte-befähigter verteilter Anwendungen

Der Ausdruck Quality of Service (QoS) beschreibt die Güte eines erbrachten Dienstes. QoS beschreibt Eigenschaften wie Antwortzeit, Verfügbarkeit, den Grad der Nachrichten-Verschlüsselung oder den Durchsatz. QoS ist sowohl für Multi-Media Anwendungen (Audio- und Video-Übertragung) als auch für Geschäftsanwendungen wichtig. Die vorgelegte Arbeit konzentriert sich dabei auf das Feld der Geschäftsanwendungen. Solche Anwendungen arbeiten mit Transaktionen wie etwa dem Bestellen eines Produkts oder der Überweisung von Geld zwischen Konten. QoS Eigenschaften solcher Anwendungen sind beispielsweise die Anzahl an Transaktionen während eines Zeitintervalls, die maximale Anzahl gleichzeitig mit dem System arbeitender Nutzer, oder die zu erwartende Verfügbarkeit. Durch Middleware kann die Realisierung von Verteilung vor dem Programmierer verborgen werden. In einer idealen Welt würde Middleware dasselbe für QoS leisten. Das heißt, der Entwickler spezifiziert nur die gewünschte Dienstgüte und kümmert sich nicht darum, wie sie realisiert wird. Das ist so aber nicht möglich, denn die zu erbringende Dienstgüte hat massive Auswirkungen auf das Design einer Applikation. Daher muss QoS schon in der Design-Phase angegangen werden, was mit einer rein Middleware-gestützten Herangehensweise nicht möglich ist. Die vorgelegte Arbeit zeigt, wie dieses Problem durch einen modellgetriebenen Ansatz behoben werden kann. Die Entwicklung beginnt dann mit einem Plattform-unabhängigen Modell (PIM), welches das Verhalten und die QoS Eigenschaften der Applikation beschreibt. Dieses Modell wird automatisch durch eine Modell-Transformation in ein Plattform-spezifisches Modell (PSM) umgewandelt. Das PSM beschreibt das Design einer Implementierung für eine spezifische Plattform und berücksichtigt dabei die im PIM beschriebenen QoS-Eigenschaften. Um dieses Szenario in der Praxis anwenden zu können, müssen zwei Probleme gelöst werden: das Modellieren von QoS Eigenschaften und die Modell-Transformation. Gegenwärtig erfordert das Erstellen einer Modell-Transformation detailliertes Wissen über die Modellierungssprache und ihre Interna. Um das zu vereinfachen, wurde im Rahmen dieser Arbeit die visuelle Regelbasierte Transformationssprache Kafka entwickelt. Kafka und die zugehörigen Werkzeuge bauen auf Graphtransformations-Theorie auf. Kafka vereinfacht das Erstellen von Transformationen weil es auf der Notation des PIM und PSM aufbaut. Daher muss der Entwickler nichts von den Interna (etwa dem Meta-Modell) verstehen. Um PIMs von QoS-fähigen Applikationen zu erstellen, wurde die Modellierungssprache PIQML entwickelt, welche auf UML 2.0 Komponenten, Hierarchischen Nachrichten Sequenz Diagrammen (HMSCs) und einer neuen Meta-Modell Erweiterung für QoS Verträge basiert. Die vorgelegte Arbeit zeigt, wie PIQML Modelle auf verschiedene Zielplattformen (Programmiersprachen und Middleware Produkte) abgebildet werden können. Basierend auf PIQML und Kafka wurde das Werkzeug Kase entwickelt, welches das Editieren von PIQML Modellen (PIMs), UML Modellen (PSMs) und Kafka Transformationen integriert. Das Ergebnis ist eine integrierte Werkzeug-Kette für das modellgetriebene Entwickeln QoS-fähiger verteilter Applikationen.The term Quality of Service (QoS) describes how well an application or service performs. Hence, QoS can describe properties such as response time, availability, the level of encryption, throughput etc. QoS is important for multi-media (i.e. video and audio applications) as well as for enterprise applications. The presented work focuses on QoS-aware enterprise applications. Enterprise applications are concerned with business transactions such as ordering a product or transferring money between two accounts. QoS properties of enterprise applications determine, for example, how many transactions the system can handle in a certain time frame, how many concurrent users it can serve, or how available the system will be. Middleware tools and libraries shield the developer almost completely from the realization of distribution. In an ideal world, QoS-enabled middleware could do the same for QoS, i.e. the developer does not have to care how QoS is realized. However, the design of an application is highly dependent on its QoS properties. This means that QoS must be tackled at the design phase and this is not possible with an approach solely based on QoS-enabled middleware. This thesis shows how a model-driven approach can overcome this limitation. The development starts with a platform independent model (PIM), which describes the behavior and QoS properties of an application. This model is automatically transformed by a model transformation into a platform specific model (PSM). The PSM describes the design for a concrete implementation on a specific platform, i.e. operating system, programming language, and middleware. Due to the automatic model transformation, tools can influence the platform-specific design and take care of the PIM QoS properties. To realize this scenario, two problems had to be solved: the modeling of QoS properties in the PIM and the model transformation. Current approaches to model transformation require in depth knowledge of the modeling language and its internals. To simplify the construction of transformers, the visual rule-based transformation language Kafka and associated tools based on graph transformation theory have been developed throughout this thesis. Kafka simplifies the implementation of transformers because it builds on the notation of the PIM and the PSM. Hence, it shields the developers of model transformers from the internals of the modeling languages, i.e. the meta models. To create PIMs of QoS-aware applications, a modeling language called PIQML has been developed which is based on UML 2.0 components, hierarchical message sequence charts, and a novel meta model extension for QoS contracts. The thesis shows how PIQML models can be mapped to several target platforms, i.e. programming languages and middleware products. Based on PIQML and Kafka, the CASE tool Kase has been developed which integrates the editing of PIQML models (i.e. PIMs), UML models (i.e. PSMs), and Kafka transformations. The result is an integrated tool chain for the model-driven development of QoS-aware distributed applications