Karlsruhe Institute of Technology (KIT)

Displaying 1-40 of 70 results

  • White Papers // May 2014

    Analysis Techniques for Supporting Harmonic Real-Time Tasks with Suspensions

    In many real-time systems, tasks may experience suspension delays when they block to access shared resources or interact with external devices such as I/O. It is known that such suspensions delays may negatively impact schedulability. Particularly in hard real-time systems, a few negative results exist on analyzing the schedulability of...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // May 2014

    Evaluating the Self-Optimization Process of the Adaptive Memory Management Architecture Self-aware Memory

    With the continuously increasing integration level, manycore processor systems are likely to be the coming system structure not only in HPC but also for desktop or mobile systems. Nowadays manycore processors like Tilera TILE, KALRAY MPPA or Intel SCC combine a rising number of cores in a tiled architecture and...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jan 2014

    Avoiding Unnecessary Write Operations in STT-MRAM for Low Power Implementation

    Spin Transfer Torque (STT) is a promising emerging memory technology because of its various advantages such as non-volatility, high density, virtually infinite endurance, scalability and CMOS compatibility. Despite all these features, high write current is still a challenge for its widespread use. When writing a value that is already stored,...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Sep 2013

    An On-Demand Scaling Stereoscopic 3D Video Streaming Service in the Cloud

    The authors describe a web service providing a complete stereoscopic 3D video multi-stream cloud application to serve a potentially very large number of clients over the Internet. The system architecture consists of a stream provider that leverages highly scalable and reliable cloud computing and storage services, with automatic load balancing...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Oct 2012

    A Declarative Recommender System for Cloud Infrastructure Services Selection

    The cloud infrastructure services landscape advances steadily leaving users in the agony of choice. Therefore, the authors present CloudRecommender, a new declarative approach for selecting Cloud-based infrastructure services. CloudRecommender automates the mapping of users' specified application requirements to cloud service configurations. They formally capture cloud service configurations in ontology and...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2012

    On Definitions of Selective Opening Security

    Assume that an adversary observes many ciphertexts, and may then ask for openings, i.e., the plaintext and the randomness used for encryption, of some of them. Do the unopened ciphertexts remain secure? There are several ways to formalize this question, and the ensuing security notions are not known to be...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Mar 2012

    David & Goliath Oblivious Affine Function Evaluation - Asymptotically Optimal Building Blocks for Universally Composable Two-Party Computation from a Single Untrusted Stateful Tamper-Proof Hardware Token

    Cryptographic assumptions regarding tamper proof hardware tokens have gained increasing attention. Even if the tamper-proof hardware is issued by one of the parties, and hence not necessarily trusted by the other, many tasks become possible: Tamper proof hardware is sufficient for universally composable protocols, for information-theoretically secure protocols, and even...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jan 2012

    Quantifying Information Flow in Programs Using Program Logics

    The authors have explained a precise quantitative information flow analysis can be built on top of a direct formalization of indistinguishability in Dynamic Logic. They have used three publicly available tools for this: the KeY system v1.6, the Z3 SMT solver v2.10, and the Barvinok tool v0.35. According to the...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jan 2012

    Waters Signatures With Optimal Security Reduction

    Waters signatures (Eurocrypt 2005) can be shown existentially unforgeable under chosen-message attacks under the assumption that the computational Diffie-Hellman problem in the underlying (pairing-friendly) group is hard. Waters signatures form a simple and efficient digital signature scheme in pairing-friendly groups. The existential unforgeability of the scheme can be proved under...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jan 2012

    Basing Obfuscation on Simple Tamper-Proof Hardware Assumptions

    Code obfuscation is one of the most powerful concepts in cryptography. It could yield functional encryption, digital rights management, and maybe even secure cloud computing. However, general code obfuscation has been proven impossible and the research then focused on obfuscating very specific functions, studying weaker security definitions for obfuscation, and...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jan 2012

    Verification of Information Flow Properties of Java Programs Without Approximations

    In this paper, the authors propose a methodology for the specification and verification of information flow properties for sequential Java programs. This proposal also covers declassification. They define an extension of the Java Modeling Language (JML) that significantly goes beyond previous approaches. The JML specification clauses are translated into proof...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Dec 2011

    (MC2)2: A Generic Decision-Making Framework and Its Application to Cloud Computing

    Cloud computing is a disruptive technology, representing a new model for Information Technology (IT) solution engineering and management that promises to introduce significant cost savings and other benefits. The adoption of Cloud computing requires a detailed comparison of infrastructure alternatives, taking a number of aspects into careful consideration. Existing methods...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Oct 2011

    Automated Extraction of Architecture-Level Performance Models of Distributed Component-Based Systems

    Modern enterprise applications have to satisfy increasingly stringent Quality-of-Service requirements. To ensure that a system meets its performance requirements, the ability to predict its performance under different configurations and workloads is essential. Architecture-level performance models describe performance-relevant aspects of software architectures and execution environments allowing to evaluate different usage profiles...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Oct 2011

    Capacity Planning for Event-Based Systems Using Automated Performance Predictions

    Event-based communication is used in different domains including telecommunications, transportation, and business information systems to build scalable distributed systems. The loose coupling of components in such systems makes it easy to vary the deployment. At the same time, the complexity to estimate the behavior and performance of the whole system...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Sep 2011

    Development and Application of GPS-Based Time Synchronization in Power Line Channel Time Characterization

    Research activities in PLC area such as measurements of time-varying channel features and evaluations of communication synchronization methodologies require a precise and stable global time reference. This paper introduces the development and application of GPS-based time synchronization for the purpose of power line channel characterizations. Algorithms have been developed to...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Sep 2011

    Self-Aware Software and Systems Engineering: A Vision and Research Roadmap

    With the increasing adoption of virtualization and the transition towards cloud computing platforms, modern IT systems and services are becoming increasingly complex and dynamic. The lack of direct control over the underlying physical hardware and the complex interactions between the applications sharing the physical infrastructure pose some major challenges in...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // May 2011

    Performance Engineering of Business Information Systems: Filling the Gap Between High-Level Business Services and Low-Level Performance Models

    With the increasing adoption of virtualization and the transition towards Cloud Computing platforms, modern business information systems are becoming increasingly complex and dynamic. This raises the challenge of guaranteeing system performance and scalability while at the same time ensuring efficient resource usage. In this paper, the authors present a historical...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // May 2011

    Automated Transformation of Component-Based Software Architecture Models to Queueing Petri Nets

    Performance predictions early in the software development process can help to detect problems before resources have been spent on implementation. The Palladio Component Model (PCM) is an example of a mature domain-specific modeling language for component-based systems enabling performance predictions at design time. PCM provides several alternative model solution methods...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2011

    Towards A Generic Quality Optimisation Framework for Component-Based System Models

    Designing Component-Based Systems (CBS) that exhibit a good trade-o between multiple quality criteria is hard. Even after functional design, many remaining degrees of freedom of different types (e.g., component deployment, component selection, server configuration) in the CBS span a large, dis-continuous design space. Automated approaches have been proposed to optimise...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2011

    MetaStorage: A Federated Cloud Storage System to Manage Consistency-Latency Tradeoffs

    Cost and scalability benefits of Cloud storage services are apparent. However, selecting a single storage service provider limits availability and scalability to the selected provider and may further cause a vendor lock-in effect. In this paper, the authors present MetaStorage, a federated Cloud storage system that can integrate diverse Cloud...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2011

    I-Core: A Run-Time Adaptive Processor for Embedded Multi-Core Systems

    The authors present the i-Core (invasive Core); an Application Specific Instruction set Processor (ASIP) with a run-time adaptive instruction set. Its adaptivity is controlled by the runtime system with respect to application properties that may vary during run-time. A reconfigurable fabric hosts the adaptive part of the instruction set whereas...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2011

    DFN@100G : A Field Trial of 100G Technologies Related to Real World Research Scenarios

    In general, it can be summarized that the 100G trial infrastructure showed a very stable behaviour during the whole duration of the test. Even high interface load did not show an increased error rate or any instability of the CRS-3 router and the DWDM system. In a long term test...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2011

    Engineering Multilevel Graph Partitioning Algorithms

    The authors present a multi-level graph partitioning algorithm using novel local improvement algorithms and global search strategies transferred from multigrid linear solvers. Local improvement algorithms are based on max-flow min-cut computations and more localized FM searches. By combining these techniques, they obtain an algorithm that is fast on the one...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2011

    Completeness Theorems With Constructive Proofs for Finite Deterministic 2-Party Functions (full Version)

    In this paper the authors present simple but comprehensive combinatorial criteria for completeness of finite deterministic 2-party functions with respect to information-theoretic security. They give a general protocol construction for efficient and statistically secure reduction of oblivious transfer to any finite deterministic 2-party function that fulfills the criteria. For the...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2011

    A Generative Model for 3D Urban Scene Understanding From Movable Platforms

    3D scene understanding is key for the success of applications such as autonomous driving and robot navigation. However, existing approaches produce a mild level of understanding, e.g., segmentation, object detection, or are not accurate enough for these applications, e.g., 3D pop-ups. In this paper, the authors propose a principled generative...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2011

    Long-run Factors Of Firm Growth - A Study Of German Firms

    This paper investigates whether the economic factors that are related to firm growth in the literature also determine the development path of firms. This means that the authors test which economic factors possess the ability to remain effective for a longer period of time. They examine three variables: firm size,...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Feb 2011

    Evaluating and Modeling Virtualization Performance Overhead for Cloud Environments

    Due to trends like Cloud Computing and Green IT, virtualization technologies are gaining increasing importance. They promise energy and cost savings by sharing physical resources, thus making resource usage more efficient. However, resource sharing and other factors have direct effects on system performance, which are not yet well-understood. Hence, performance...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Feb 2011

    Performance Certification of Software Components

    Non-functional properties of software should be specified early in the development process. In a distributed process of software development, this means that quality requirements must be made explicit in the specification, and the developing party of a commissioned component needs to deliver not only the implemented component, but also a...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Feb 2011

    Combined Data Structure for Previous-And Next-Smaller-Values

    The authors consider the situation where a static array A[1, n] can be preprocessed such that the following three queries can be answered in constant time: previous- and next-smaller-value-queries, where given a position i in A, one searches for the next position p to the left (or right) of i...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jan 2011

    Focussing Multi-Objective Software Architecture Optimization Using Quality of Service Bounds

    Quantitative prediction of non-functional properties, such as performance, reliability, and costs, of software architectures supports systematic software engineering. Even though there usually is a rough idea on bounds for quality of service, the exact required values may be unclear and subject to trade-o s. Designing architectures that exhibit such good...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jan 2011

    Formal Semantics for the Java Modeling Language

    A common critique of formal methods in software development practise is, that they are not readily understandable and thus not widely used. The Java Modeling Language (JML) was created in an attempt to bridge that gap. By building upon the syntax of Java it is meant to be easily accessible...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jan 2011

    Analysis of the Performance-Influencing Factors of Virtualization Platforms

    Nowadays, virtualization solutions are gaining increasing importance. By enabling the sharing of physical resources, thus making resource usage more efficient, they promise energy and cost savings. Additionally, virtualization is the key enabling technology for Cloud Computing and server consolidation. However, the effects of sharing resources on system performance are not...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Dec 2010

    Online Performance Prediction With Architecture-Level Performance Models

    Today's enterprise systems based on increasingly complex software architectures often exhibit poor performance and resource efficiency thus having high operating costs. This is due to the inability to predict at run-time the effect of changes in the system environment and adapt the system accordingly. The authors propose a new performance...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Dec 2010

    On the Accuracy of Software-Based Energy Estimation Techniques

    This paper examines the accuracy of software-based on-line energy estimation techniques. It evaluates today's most widespread energy estimation model in order to investigate whether the current methodology of pure software-based energy estimation running on a sensor node itself can indeed reliably and accurately determine its energy consumption - independent of...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Nov 2010

    Perspective of the Large Scale Data Facility (LSDF) Supporting Nuclear Fusion Applications

    To cope with the growing requirements of data intensive scientific experiments, models and simulations the Large Scale Data Facility (LSDF) at KIT aims to support many scientific disciplines. The LSDF is a distributed storage facility at Exabyte scale providing storage, archives, data bases and meta data repositories. Open interfaces and...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Oct 2010

    On the Transmission Capacity of Wireless Multi-Channel Ad Hoc Networks With Local FDMA Scheduling

    The problem of the capacity of multi-channel interference-limited ad hoc networks with local frequency planning is examined in the transmission capacity framework. Bounds on outage and transmission capacity are given. If local frequency planning, i.e., frequency domain orthogonalization of neighbors in the communication range, is employed, transmission capacity can be...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Oct 2010

    Challenges and Opportunities of Cloud Computing

    In recent years, Cloud Computing has become an emerging technology that gains wide influence on IT systems. Cloud Computing is a distributed computing model for enabling service-oriented, on-demand network access to rapidly scalable resources. Such resources include Infrastructure as a Service (IaaS), development and run-time Platforms as a Service (PaaS),...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Sep 2010

    Cloud Computing: New Business Opportunities for Telecommunications Companies?

    Cloud computing has recently shifted into the center of attention of Telecommunications Companies. Deutsche Telekom, for example, just announced the importance of cloud computing as one of their leading growth sectors (Deutsche Telekom Press Release, 2010). Also other important telecommunication players such as AT&T, Vodafone and Telef?nica are expanding their...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Aug 2010

    Cloud Services From a Consumer Perspective

    Although there is an increased attention on Cloud Computing in the academic literature in the recent years, most research work focus on technical aspects of cloud computing. Research on consumers' preferences for cloud services is limited to studies from consulting and industry companies. This paper fills the gap by empirically...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Aug 2010

    From Monolithic to Component-Based Performance Evaluation of Software Architectures: A Series of Experiments Analyzing Accuracy and Effort

    Model-based performance evaluation methods for software architectures can help architects to assess design alternatives and save costs for late life-cycle performance fixes. A recent trend is component-based performance modelling, which aims at creating reusable performance models; a number of such methods have been proposed during the last decade. Their accuracy...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Nov 2008

    Performance-Oriented Design Space Exploration

    Architectural models of component-based software systems are evaluated for functional properties and/or extra-functional properties (e.g. by doing performance predictions). However, after getting the results of the evaluations and recognising that requirements are not met, most existing approaches leave the software architect alone with finding new alternatives to her current design...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jan 2012

    Quantifying Information Flow in Programs Using Program Logics

    The authors have explained a precise quantitative information flow analysis can be built on top of a direct formalization of indistinguishability in Dynamic Logic. They have used three publicly available tools for this: the KeY system v1.6, the Z3 SMT solver v2.10, and the Barvinok tool v0.35. According to the...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jan 2012

    Verification of Information Flow Properties of Java Programs Without Approximations

    In this paper, the authors propose a methodology for the specification and verification of information flow properties for sequential Java programs. This proposal also covers declassification. They define an extension of the Java Modeling Language (JML) that significantly goes beyond previous approaches. The JML specification clauses are translated into proof...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Oct 2012

    A Declarative Recommender System for Cloud Infrastructure Services Selection

    The cloud infrastructure services landscape advances steadily leaving users in the agony of choice. Therefore, the authors present CloudRecommender, a new declarative approach for selecting Cloud-based infrastructure services. CloudRecommender automates the mapping of users' specified application requirements to cloud service configurations. They formally capture cloud service configurations in ontology and...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Dec 2011

    (MC2)2: A Generic Decision-Making Framework and Its Application to Cloud Computing

    Cloud computing is a disruptive technology, representing a new model for Information Technology (IT) solution engineering and management that promises to introduce significant cost savings and other benefits. The adoption of Cloud computing requires a detailed comparison of infrastructure alternatives, taking a number of aspects into careful consideration. Existing methods...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Dec 2010

    Online Performance Prediction With Architecture-Level Performance Models

    Today's enterprise systems based on increasingly complex software architectures often exhibit poor performance and resource efficiency thus having high operating costs. This is due to the inability to predict at run-time the effect of changes in the system environment and adapt the system accordingly. The authors propose a new performance...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Sep 2011

    Self-Aware Software and Systems Engineering: A Vision and Research Roadmap

    With the increasing adoption of virtualization and the transition towards cloud computing platforms, modern IT systems and services are becoming increasingly complex and dynamic. The lack of direct control over the underlying physical hardware and the complex interactions between the applications sharing the physical infrastructure pose some major challenges in...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jan 2011

    Focussing Multi-Objective Software Architecture Optimization Using Quality of Service Bounds

    Quantitative prediction of non-functional properties, such as performance, reliability, and costs, of software architectures supports systematic software engineering. Even though there usually is a rough idea on bounds for quality of service, the exact required values may be unclear and subject to trade-o s. Designing architectures that exhibit such good...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Aug 2010

    From Monolithic to Component-Based Performance Evaluation of Software Architectures: A Series of Experiments Analyzing Accuracy and Effort

    Model-based performance evaluation methods for software architectures can help architects to assess design alternatives and save costs for late life-cycle performance fixes. A recent trend is component-based performance modelling, which aims at creating reusable performance models; a number of such methods have been proposed during the last decade. Their accuracy...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Feb 2011

    Performance Certification of Software Components

    Non-functional properties of software should be specified early in the development process. In a distributed process of software development, this means that quality requirements must be made explicit in the specification, and the developing party of a commissioned component needs to deliver not only the implemented component, but also a...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Oct 2011

    Automated Extraction of Architecture-Level Performance Models of Distributed Component-Based Systems

    Modern enterprise applications have to satisfy increasingly stringent Quality-of-Service requirements. To ensure that a system meets its performance requirements, the ability to predict its performance under different configurations and workloads is essential. Architecture-level performance models describe performance-relevant aspects of software architectures and execution environments allowing to evaluate different usage profiles...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Oct 2011

    Capacity Planning for Event-Based Systems Using Automated Performance Predictions

    Event-based communication is used in different domains including telecommunications, transportation, and business information systems to build scalable distributed systems. The loose coupling of components in such systems makes it easy to vary the deployment. At the same time, the complexity to estimate the behavior and performance of the whole system...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // May 2011

    Performance Engineering of Business Information Systems: Filling the Gap Between High-Level Business Services and Low-Level Performance Models

    With the increasing adoption of virtualization and the transition towards Cloud Computing platforms, modern business information systems are becoming increasingly complex and dynamic. This raises the challenge of guaranteeing system performance and scalability while at the same time ensuring efficient resource usage. In this paper, the authors present a historical...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // May 2011

    Automated Transformation of Component-Based Software Architecture Models to Queueing Petri Nets

    Performance predictions early in the software development process can help to detect problems before resources have been spent on implementation. The Palladio Component Model (PCM) is an example of a mature domain-specific modeling language for component-based systems enabling performance predictions at design time. PCM provides several alternative model solution methods...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jun 2010

    Engineering of Next Generation Self-Aware Software Systems: A Research Roadmap

    With the increasing adoption of virtualization and the transition towards cloud computing platforms, modern enterprise software systems are becoming increasingly complex and dynamic. The lack of direct control over the underlying physical hardware and the resulting gap between logical and physical resource allocations pose some major challenges in providing Quality-of-Service...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // May 2010

    Towards Formal Certification of Software Components

    Software certification as it is practised today guarantees that certain standards are kept in the process of software development. However, this does not make any statements about the actual quality of implemented code. The authors propose an approach to certify the non-functional properties of component-based software which is based on...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Feb 2010

    Benchmarking Publish/Subscribe-Based Messaging Systems

    Publish/subscribe-based messaging systems are used increasingly often as a communication mechanism in data-oriented web applications. Such applications often pose serious performance and scalability challenges. To address these challenges, it is important that systems are tested using benchmarks to evaluate their performance and scalability before they are put into production. In...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jan 2010

    Automated Benchmarking of Java APIs

    Performance is an extra-functional property of software systems which is often critical for achieving sufficient scalability or efficient resource utilisation. As many applications are built using Application Programmer Interfaces (APIs) of execution platforms and external components, the performance of the used API implementations has a strong impact on the performance...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Dec 2009

    Reverse Engineering Component Models for Quality Predictions

    Legacy applications are still widely spread. If a need to change deployment or update its functionality arises, it becomes difficult to estimate the performance impact of such modifications due to absence of corresponding models. In this paper, the authors present an extendable integrated environment based on Eclipse developed in the...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Mar 2010

    A Change Metamodel for the Evolution of MOF-Based Metamodels

    The evolution of software systems often produces incompatibilities with existing data and applications. To prevent incompatibilities, changes have to be well-planned, and developers should know the impact of changes on a software system. This consideration also applies to the field of model-driven development, where changes occur with the modification of...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jun 2010

    A Prediction Model for Software Performance in Symmetric Multiprocessing Environments

    The broad introduction of multi-core processors made Symmetric MultiProcessing (SMP) environments mainstream. The additional cores can significantly increase software performance. However, their actual benefit depends on the operating system scheduler's capabilities, the system's workload, and the software's degree of concurrency. The load distribution on the available processors (or cores) strongly...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2010

    Statistical Inference of Software Performance Models for Parametric Performance Completions

    Software Performance Engineering (SPE) enables software architects to ensure high performance standards for their applications. However, applying SPE in practice is still challenging. Most enterprise applications include a large software basis, such as middleware and legacy systems. In many cases, the software basis is the determining factor of the system's...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2010

    Systematic Refinement of Performance Models for Concurrent Component-Based Systems

    Model-driven performance prediction methods require detailed design models to evaluate the performance of software systems during early development stages. However, the complexity of detailed prediction models and the semantic gap between modelled performance concerns and functional concerns prevents many developers to address performance. As a solution to this problem, systematic...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2010

    Evaluating Maintainability With Code Metrics for Model-to-Model Transformations

    Using model-to-model transformations to generate analysis models or code from architecture models is sought to promote compliance and reuse of components. The maintainability of transformations is influenced by various characteristics - as with every programming language artifact. Code metrics are often used to estimate code maintainability. However, most of the...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // May 2010

    Towards Self-Aware Performance and Resource Management in Modern Service-Oriented Systems

    Modern service-oriented systems have increasingly complex loosely-coupled architectures that often exhibit poor performance and resource efficiency and have high operating costs. This is due to the inability to predict at run-time the effect of dynamic changes in the system environment (e.g., varying service workloads) and adapt the system configuration accordingly....

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jun 2009

    Performance Evaluation of Scheduling Policies in Symmetric Multiprocessing Environments

    The shift of hardware architecture towards parallel execution led to a broad usage of multi-core processors in desktop systems and in server systems. The benefit of additional processor cores for software performance depends on the software's parallelism as well as the operating system scheduler's capabilities. Especially, the load on the...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // May 2009

    Automated Feature Model-Based Generation of Refinement Transformations

    Model-driven application engineering builds on the concept of model transformations. To weave additional refinement parts into an application model, so-called refinement transformations are used. In many cases these refinement parts are highly variable and configurable. Such a configuration could depend on application specific features. Today, application developers need to define...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Jun 2009

    TIMERMETER: Quantifying Properties of Software Timers for System Analysis

    To analyze run-time behaviour and performance of software systems, accurate time measurements are needed. For this, timer methods are used, which are based on hardware timers and counters that are read and processed by several software layers. These processing layers introduce overhead and delays that impact accuracy and statistical validity...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Feb 2009

    Using Heuristics to Automate Parameter Generation for Benchmarking of Java Methods

    Automated generation of method parameters is needed in benchmarking scenarios where manual or random generation of parameters are not suitable, do not scale or are too costly. However, for a method to execute correctly, the generated input parameters must not violate implicit semantical constraints, such as ranges of numeric parameters...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Feb 2009

    Automatic, Model-Based Software Performance Improvement for Component-Based Software Designs

    Formal performance prediction methods, based on queueing network models, allow evaluating software architectural designs for performance. Existing methods provide prediction results such as response times and throughputs, but do not guide the software architect on how to improve the design. The authors propose a novel approach to optimise the expected...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2009

    Reverse Engineering of Parametric Behavioural Service Performance Models From Black-Box Components

    Integrating heterogeneous software systems becomes increasingly important. It requires combining existing components to form new applications. Such new applications are required to satisfy non-functional properties, such as performance. Design-time performance prediction of new applications built from existing components helps to compare design decisions before actually implementing them to the full,...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Oct 2009

    Reverse Engineering Software-Models of Component-Based Systems

    An increasing number of software systems is developed using component technologies such as COM, CORBA, or EJB. Still, there is a lack of support to reverse engineer such systems. Existing approaches claim reverse engineering of components, but do not support composite components. Also, external dependencies such as required interfaces are...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Sep 2008

    Software Extension Mechanisms

    Industrial software projects not only have to deal with the number of features in the software system. Also issues like quality, flexibility, reusability, extensibility, developer and user acceptance are key factors in these days. An architecture paradigm targeting those issues are extension mechanisms which are for example used by component...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Mar 2010

    The Ricommander - Rating Recommendations for Corporate Community Portals

    This paper points at the large potentials that corporate community portals can have to support the business model of companies. In particular corporate community portals of the next generation are characterized by the integration of business intelligence tools which can facilitate or even automate many business processes. However, this paper...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // May 2010

    Technical Report: Secure Cloud Computing Through a Separation of Duties

    Cloud Computing offers many opportunities but also introduces new risks. A user who outsources a database into the Cloud loses control over his data. While the data can be secured against external threats using standard techniques, the service providers themselves have to be trusted to ensure privacy. This work proposes...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Oct 2009

    Grid Virtualization Engine: Design, Implementation and Evaluation

    Virtual machines offer various advantages such as easy configuration, management, development and deployment of computing resources for cyberinfrastructures. Recent advances of employing virtual machines for Grid computing can help Grid communities to solve research issues, for example, QoS provision and computing environment customization. The heterogeneous virtualization implementations, however, bring challenges...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // May 2009

    Market Power In The German Wholesale Electricity Market

    Wholesale electricity prices have increased dramatically in Europe and especially in Germany. It has been argued that utilities have been exercising market power by withholding available power plant capacity. In this paper authors investigate the exercise of market power in the German wholesale electricity market with an agent-based simulation model...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Feb 2011

    Combined Data Structure for Previous-And Next-Smaller-Values

    The authors consider the situation where a static array A[1, n] can be preprocessed such that the following three queries can be answered in constant time: previous- and next-smaller-value-queries, where given a position i in A, one searches for the next position p to the left (or right) of i...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2011

    Engineering Multilevel Graph Partitioning Algorithms

    The authors present a multi-level graph partitioning algorithm using novel local improvement algorithms and global search strategies transferred from multigrid linear solvers. Local improvement algorithms are based on max-flow min-cut computations and more localized FM searches. By combining these techniques, they obtain an algorithm that is fast on the one...

    Provided By Karlsruhe Institute of Technology (KIT)

  • White Papers // Apr 2011

    Completeness Theorems With Constructive Proofs for Finite Deterministic 2-Party Functions (full Version)

    In this paper the authors present simple but comprehensive combinatorial criteria for completeness of finite deterministic 2-party functions with respect to information-theoretic security. They give a general protocol construction for efficient and statistically secure reduction of oblivious transfer to any finite deterministic 2-party function that fulfills the criteria. For the...

    Provided By Karlsruhe Institute of Technology (KIT)