Trusted computing enhanced openid

Abstrac

Mejora de sensores vítreos sol-gel para la conservación preventiva de materiales históricos frente a la acidez

[ES] Los sensores a base de recubrimientos vítreos sol-gel dopados con ácido 2[4-(dimetil-amino) fenilazo] benzoico son capaces de cambiar su absorción óptica cuando se someten a distintas concentraciones de iones H3O+ y OH-. La respuesta de los sensores en ensayos de campo se estudió en Cracovia (Polonia) variando el procedimiento normal de uso, con el fin de mejorar su respuesta. Se midieron tanto los parámetros ópticos de los sensores como las condiciones ambientales (temperatura, humedad, presión y concentraciones de SO2 y de NOx). La respuesta de los sensores se analizó en términos de los cambios de su absorción visible. Dichos cambios se deben a reacciones locales de neutralización que tienen lugar en la superficie de los sensores, debido al efecto conjunto de los contaminantes de carácter ácido y a la humedad ambiental. Se establecieron correlaciones entre la concentración del contaminante principal (SO2) y la respuesta de los sensores para elaborar una calibración directa entre la absorción óptica y el pH ambiental. Los sensores pueden detectar y evaluar la acidez ambiental, así como alertar sobre la concentración de contaminantes ácidos que pueden dañar a la mayoría de los materiales históricos.[EN] Sensors based on sol-gel glassy coatings doped with 2[4-(dimethyl-amino) phenylazo] benzoic acid are able to change their optical absorption when they are submitted to different concentration of H3O+ and OH-. The sensors behaviour in field tests was studied in Cracow (Poland), varying the normal procedure of operation to improve their response. Both the sensors optical parameters and the environmental conditions (temperature, humidity, pressure, SO2 and NOx concentrations) were measured. The sensors response was analysed in terms of their visible absorbance changes, which are due to local neutralisation reactions in the sensors surface by the join effect of acid pollutants and humidity. Correlations between the main acid pollutant (SO2) concentration and the sensors response are established to provide a relation between the optical absorption and the environmental pH. The sensors are able to detect and monitorise environmental acidity, as well as to alert on the pollutant concentration that may damage most of the historical materials.The authors wish to acknowledge bilateral Polish-Spanish project Ref. PAN-CSIC 2003PL0011, European Marie Curie project Ref. MERG-CT-2004-516436 and Spanish project Ref. CICYT-MAT-2003-03231 for financing support. N.C. acknowledges CSIC-ESF for an I3P postdoctoral contract.Peer reviewe

Tree-formed Verification Data for Trusted Platforms

The establishment of trust relationships to a computing platform relies on validation processes. Validation allows an external entity to build trust in the expected behaviour of the platform based on provided evidence of the platform's configuration. In a process like remote attestation, the 'trusted' platform submits verification data created during a start up process. These data consist of hardware-protected values of platform configuration registers, containing nested measurement values, e.g., hash values, of loaded or started components. Commonly, the register values are created in linear order by a hardware-secured operation. Fine-grained diagnosis of components, based on the linear order of verification data and associated measurement logs, is not optimal. We propose a method to use tree-formed verification data to validate a platform. Component measurement values represent leaves, and protected registers represent roots of a hash tree. We describe the basic mechanism of validating a platform using tree-formed measurement logs and root registers and show an logarithmic speed-up for the search of faults. Secure creation of a tree is possible using a limited number of hardware-protected registers and a single protected operation. In this way, the security of tree-formed verification data is maintained.Comment: 15 pages, 11 figures, v3: Reference added, v4: Revised, accepted for publication in Computers and Securit

Impact of CaSO4-rich soil on Miocene surface preservation and Quaternary sinuous to meandering channel forms in the hyperarid Atacama Desert

The Atacama Desert is the driest and oldest desert on Earth. Despite the abundance evidence for long-term landscape stability, there are subtle signs of localised fluvial erosion and deposition since the onset of hyperaridity in the rock record. In the dry core of the Atacama Desert, pluvial episodes allowed antecedent drainage to incise into uplifting fault scarps, which in turn generated sinuous to meandering channels. Incision of ancient alluvial fan surfaces occurred during intermittent fluvial periods, albeit without signs of surface erosion. Fluvial incision during predominantly hyperarid climate periods is evident from these channels in unconsolidated alluvium. The absence of dense vegetation to provide bank stability and strength led us to investigate the potential role of regionally ubiquitous CaSO4-rich surface cover. This has enabled the preservation of Miocene surfaces and we hypothesize that it provided the required bank stability by adding strength to the upper decimetre to meter of incised alluvium to allow high sinuosity of stream channels to form during pluvial episodes in the Quaternary

The geodynamic and limnological evolution of Balkan Lake Ohrid, possibly the oldest extant lake in Europe

Studies of the upper 447 m of the DEEP site sediment succession from central Lake Ohrid, Balkan Peninsula, North Macedonia and Albania provided important insights into the regional climate history and evolutionary dynamics since permanent lacustrine conditions established at 1.36 million years ago (Ma). This paper focuses on the entire 584-m-long DEEP sediment succession and a comparison to a 197-m-long sediment succession from the Pestani site ~5 km to the east in the lake, where drilling ended close to the bedrock, to unravel the earliest history of Lake Ohrid and its basin development. 26Al/10Be dating of clasts from the base of the DEEP sediment succession implies that the sedimentation in the modern basin started at c. 2 Ma. Geophysical, sedimentological and micropalaeontological data allow for chronological information to be transposed from the DEEP to the Pestani succession. Fluvial conditions, slack water conditions, peat formation and/or complete desiccation prevailed at the DEEP and Pestani sites until 1.36 and 1.21 Ma, respectively, before a larger lake extended over both sites. Activation of karst aquifers to the east probably by tectonic activity and a potential existence of neighbouring Lake Prespa supported filling of Lake Ohrid. The lake deepened gradually, with a relatively constant vertical displacement rate of ~0.2 mm a−1 between the central and the eastern lateral basin and with greater water depth presumably during interglacial periods. Although the dynamic environment characterized by local processes and the fragmentary chronology of the basal sediment successions from both sites hamper palaeoclimatic significance prior to the existence of a larger lake, the new data provide an unprecedented and detailed picture of the geodynamic evolution of the basin and lake that is Europe’s presumed oldest extant freshwater lake

Mediterranean winter rainfall in phase with African monsoons during the past 1.36 million years

Mediterranean climates are characterized by strong seasonal contrasts between dry summers and wet winters. Changes in winter rainfall are critical for regional socioeconomic development, but are difficult to simulate accurately1 and reconstruct on Quaternary timescales. This is partly because regional hydroclimate records that cover multiple glacial–interglacial cycles2,3 with different orbital geometries, global ice volume and atmospheric greenhouse gas concentrations are scarce. Moreover, the underlying mechanisms of change and their persistence remain unexplored. Here we show that, over the past 1.36 million years, wet winters in the northcentral Mediterranean tend to occur with high contrasts in local, seasonal insolation and a vigorous African summer monsoon. Our proxy time series from Lake Ohrid on the Balkan Peninsula, together with a 784,000-year transient climate model hindcast, suggest that increased sea surface temperatures amplify local cyclone development and refuel North Atlantic low-pressure systems that enter the Mediterranean during phases of low continental ice volume and high concentrations of atmospheric greenhouse gases. A comparison with modern reanalysis data shows that current drivers of the amount of rainfall in the Mediterranean share some similarities to those that drive the reconstructed increases in precipitation. Our data cover multiple insolation maxima and are therefore an important benchmark for testing climate model performance

The geodynamic and limnological evolution of Balkan Lake Ohrid, possibly the oldest extant lake in Europe

Studies of the upper 447 m of the DEEP site sediment succession from central Lake Ohrid, Balkan Peninsula, North Macedonia and Albania provided important insights into the regional climate history and evolutionary dynamics since permanent lacustrine conditions established at 1.36 million years ago (Ma). This paper focuses on the entire 584-m-long DEEP sediment succession and a comparison to a 197-m-long sediment succession from the Pestani site ~5 km to the east in the lake, where drilling ended close to the bedrock, to unravel the earliest history of Lake Ohrid and its basin development. 26Al/10Be dating of clasts from the base of the DEEP sediment succession implies that the sedimentation in the modern basin started at c. 2 Ma. Geophysical, sedimentological and micropalaeontological data allow for chronological information to be transposed from the DEEP to the Pestani succession. Fluvial conditions, slack water conditions, peat formation and/or complete desiccation prevailed at the DEEP and Pestani sites until 1.36 and 1.21 Ma, respectively, before a larger lake extended over both sites. Activation of karst aquifers to the east probably by tectonic activity and a potential existence of neighbouring Lake Prespa supported filling of Lake Ohrid. The lake deepened gradually, with a relatively constant vertical displacement rate of ~0.2 mm a−1 between the central and the eastern lateral basin and with greater water depth presumably during interglacial periods. Although the dynamic environment characterized by local processes and the fragmentary chronology of the basal sediment successions from both sites hamper palaeoclimatic significance prior to the existence of a larger lake, the new data provide an unprecedented and detailed picture of the geodynamic evolution of the basin and lake that is Europe’s presumed oldest extant freshwater lake

Konfliktanalyse bei der Komposition komponentenbasierter Systeme

Ein Ziel der komponentenbasierten Softwareentwicklung besteht in der Wiederverwendung bereits entwickelter Komponenten zur Verbesserung der Qualität und zur Verminderung der Kosten des Softwareentwicklungsprozesses. Die Wiederverwendung von bestehenden Komponenten erfordert jedoch die sorgfältige Integration in das zu entwickelnde System und wird erschwert durch unterschiedliche Middlewaretechnologien, unterschiedliche Kommunikations- und Interoperationsmechanismen dieser Technologien sowie durch unterschiedliche und zum Teil unvollständige Komponentenspezifikationen. Das grundlegende Ziel dieser Arbeit ist die Unterstützung der Komponentenintegration durch eine ausführliche Konfliktanalyse, welche bestehende Inkompatibilitäten von zu integrierenden Komponenten aufzeigt. Dazu wird ein Framework bereitgestellt, welches es erlaubt, Komponenten unterschiedlicher Technologien im Rahmen eines UML-basierten Entwicklungsprozesses zu prüfen und die (teil-) automatische Generierung von Konnektoren vorzubereiten. Im Gegensatz zu bisherigen Anstäzen ermöglicht dieses Framework die Prüfung von Komponenten unterschiedlicher Middlewaretechnologien in Hinblick auf strukturelle, semantische und kommunikative Differenzen. Insbesondere die Einbeziehung von Kommunikationseigenschaften, welche die von den beteiligten Komponenten verwendeten Kommunikationsmechanismen der zugrundeliegenden Middlewaretechnologien beschreiben, wird zur Zeit von keinem anderen Integrationsframework angeboten. Das vorgestellte Framework basiert auf einem modellzentrierten Ansatz im Rahmen der Model Driven Architecture (MDA). Dies bedeutet, dass sowohl Komponentenspezifikationen auf verschiedenen Ebenen verwaltet werden können als auch dass Modelltransformationen unterstützt werden. Die Konfliktanalyse basiert auf einem kanonischen plattformunabhängigen Komponentenmodell, welches von Plattformspezifika abstrahiert. Komponenten, die auf Grundlage einer speziellen Middlewaretechnologie definiert wurden, werden durch Modelltransformationen in das kanonische Modell abstrahiert. Umgekehrt können jedoch auch plattformunabhängige Komponentenspezifikationen in Spezifikationen spezieller Middlewaretechnologien spezialisiert werden. Als Besonderheit unterstützt das Framework dabei parametrisierbare Modelltransformationen, so dass sich je nach Nutzervorstellungen optimale Transformationen durchführen lassen. Um die Verwendung des Frameworks in unterschiedliche Anwendungsszenarien und -domänen zu ermöglichen, wurde es möglichst flexibel definiert. Somit können sowohl unterschiedliche Middlewaretechnologien und Typsysteme als auch unterschiedliche Spezifikationssprachen in das Framework integriert werden. Zudem können zusätzliche Daten als RDF Statements an beliebige Elemente von Komponenten notiert und über zusätzliche Analyseverfahren ausgewertet werden.Component Based Software Engineering is an emerging discipline that aims at improving software development by means of artifact reuse within a systematically applied construction process. The idea of reuse involves integrating components rather than reinventing and reimplementing existing artifacts. Unfortunately, reuse of existing components is a complex undertaking because of different technologies, different communication forms, and incomplete component specifications. The objective of this work concerns the improvement of component integration by providing extended conflict analysis capabilities, which help to identify mismatches between components that hinder a direct integration. The work defines a Framework for Component Conflict Analysis and Composition that serves as a basis of component integration. The framework is able to handle components of different technologies and it is compatible with a UML-based development process. As a result, it provides the inevitable preparatory work that is required for a semi-automatic connector generation. Contrary to existing approaches, the framework allows analyzing components of different middleware technologies by checking compatibility between their type, behavior, and communication related property specifications. Especially, analysis of required and provided communication properties, which takes the middleware context of components into account is not available in comparable integration frameworks. Components of different technologies cannot be directly compared as they are defined relative to different programming languages, type systems, and middleware technologies. Therefore, the framework is based on a model centric approach within the scope of the Model-Driven Architecture (MDA). Consequently, the framework distinguishes platform independent and platform dependent component specifications. Conflict analysis is based on a platform independent canonical model that represents the least common denominator of components in middleware technologies. Furthermore, the framework provides model transformations that allow abstraction and refinement of components between different abstraction levels. Thereby, the framework supports parametric model transformations as a special feature, which take user requirements into account and result in optimal translations. In order to gain a solution, which is adaptable to different situations and application domains, the framework offers a highly flexible architecture. Consequently, we can integrate new middleware technologies, their type systems as well as additional specification languages into the framework