Metrics and Algorithms for Processing Multiple Continuous Queries

Data streams processing is an emerging research area that is driven by the growing need for monitoring applications. A monitoring application continuously processes streams of data for interesting, significant, or anomalous events. Such applications include tracking the stock market, real-time detection of diseaseoutbreaks, and environmental monitoring via sensor networks.Efficient employment of those monitoring applications requires advanced data processing techniques that can support the continuous processing of unbounded rapid data streams. Such techniques go beyond the capabilities of the traditional store-then-query Data BaseManagement Systems. This need has led to a new data processing paradigm and created a new generation of data processing systems,supporting continuous queries (CQ) on data streams.Primary emphasis in the development of first generation Data Stream Management Systems (DSMSs) was given to basic functionality. However, in order to support large-scale heterogeneous applications that are envisioned for subsequent generations of DSMSs, greater attention willhave to be paid to performance issues. Towards this, this thesis introduces new algorithms and metrics to the current design of DSMSs.This thesis identifies a collection of quality ofservice (QoS) and quality of data (QoD) metrics that are suitable for a wide range of monitoring applications. The establishment of well-defined metrics aids in the development of novel algorithms that are optimal with respect to a particular metric. Our proposed algorithms exploit the valuable chances for optimization that arise in the presence of multiple applications. Additionally, they aim to balance the trade-off between the DSMS's overall performance and the performance perceived by individual applications. Furthermore, we provide efficient implementations of the proposed algorithms and we also extend them to exploit sharing in optimized multi-query plans and multi-stream CQs. Finally, we experimentally show that our algorithms consistently outperform the current state of the art

PhyNetLab: An IoT-Based Warehouse Testbed

Future warehouses will be made of modular embedded entities with communication ability and energy aware operation attached to the traditional materials handling and warehousing objects. This advancement is mainly to fulfill the flexibility and scalability needs of the emerging warehouses. However, it leads to a new layer of complexity during development and evaluation of such systems due to the multidisciplinarity in logistics, embedded systems, and wireless communications. Although each discipline provides theoretical approaches and simulations for these tasks, many issues are often discovered in a real deployment of the full system. In this paper we introduce PhyNetLab as a real scale warehouse testbed made of cyber physical objects (PhyNodes) developed for this type of application. The presented platform provides a possibility to check the industrial requirement of an IoT-based warehouse in addition to the typical wireless sensor networks tests. We describe the hardware and software components of the nodes in addition to the overall structure of the testbed. Finally, we will demonstrate the advantages of the testbed by evaluating the performance of the ETSI compliant radio channel access procedure for an IoT warehouse

Preliminary specification and design documentation for software components to achieve catallaxy in computational systems

This Report is about the preliminary specifications and design documentation for software components to achieve Catallaxy in computational systems. -- Die Arbeit beschreibt die Spezifikation und das Design von Softwarekomponenten, um das Konzept der Katallaxie in Grid Systemen umzusetzen. Eine Einführung ordnet das Konzept der Katallaxie in bestehende Grid Taxonomien ein und stellt grundlegende Komponenten vor. Anschließend werden diese Komponenten auf ihre Anwendbarkeit in bestehenden Application Layer Netzwerken untersucht.Grid Computing

Proceedings of the first international workshop on Investigating dataflow in embedded computing architectures (IDEA 2015), January 21, 2015, Amsterdam, The Netherlands

IDEA '15 held at HiPEAC 2015, Amsterdam, The Netherlands on January 21st, 2015 is the rst workshop on Investigating Data ow in Embedded computing Architectures. This technical report comprises of the proceedings of IDEA '15. Over the years, data ow has been gaining popularity among Embedded Systems researchers around Europe and the world. However, research on data ow is limited to small pockets in dierent communities without a common forum for discussion. The goal of the workshop was to provide a platform to researchers and practitioners to present work on modelling and analysis of present and future high performance embedded computing architectures using data ow. Despite being the rst edition of the workshop, it was very pleasant to see a total of 14 submissions, out of which 6 papers were selected following a thorough reviewing process. All the papers were reviewed by at least 5 reviewers. This workshop could not have become a reality without the help of a Technical Program Committee (TPC). The TPC members not only did the hard work to give helpful reviews in time, but also participated in extensive discussion following the reviewing process, leading to an excellent workshop program and very valuable feedback to authors. Likewise, the Organisation Committee also deserves acknowledgment to make this workshop a successful event. We take this opportunity to thank everyone who contributed in making this workshop a success

Proceedings of the first international workshop on Investigating dataflow in embedded computing architectures (IDEA 2015), January 21, 2015, Amsterdam, The Netherlands

IDEA '15 held at HiPEAC 2015, Amsterdam, The Netherlands on January 21st, 2015 is the rst workshop on Investigating Data ow in Embedded computing Architectures. This technical report comprises of the proceedings of IDEA '15. Over the years, data ow has been gaining popularity among Embedded Systems researchers around Europe and the world. However, research on data ow is limited to small pockets in dierent communities without a common forum for discussion. The goal of the workshop was to provide a platform to researchers and practitioners to present work on modelling and analysis of present and future high performance embedded computing architectures using data ow. Despite being the rst edition of the workshop, it was very pleasant to see a total of 14 submissions, out of which 6 papers were selected following a thorough reviewing process. All the papers were reviewed by at least 5 reviewers. This workshop could not have become a reality without the help of a Technical Program Committee (TPC). The TPC members not only did the hard work to give helpful reviews in time, but also participated in extensive discussion following the reviewing process, leading to an excellent workshop program and very valuable feedback to authors. Likewise, the Organisation Committee also deserves acknowledgment to make this workshop a successful event. We take this opportunity to thank everyone who contributed in making this workshop a success

A architecture for MHEG objects

Hypermedia applications are one of the most recent and most demanding computer uses. It is accepted that one of the main impediments to their widespread use is the lack of standards, and the lack of Open Systems with the possibility of having documents interchangeable between different hardware and software platforms. Several standards are emerging, one of which is the one being developed by the ISO/IEC WG12 known as the Multimedia and Hypermedia Information Coding Expert Group (MHEG). As desktop systems become more powerful, one of the main users of hypermedia applications is the home market. Therefore it is important to have standards and applications suitable for those platforms. This work reviews existing proposals for hypermedia architectures and interchange standards. It then assesses the suitability of the MHEG standard for use in open, distributed, and extensible hypermedia systems. An architecture for the implementa­tion of MHEG objects taking into account the limitations imposed by current desktop computers is also proposed. To assess the suitability of the proposed architecture, a prototype has been imple­mented. An analysis of the performance obtained in the prototype is presented and conclusions on the requirements for future implementations drawn. Finally, some suggestions to improve the MHEG standard are made

Demand-driven data acquisition for large scale fleets

Automakers manage vast fleets of connected vehicles and face an ever-increasing demand for their sensor readings. This demand originates from many stakeholders, each potentially requiring different sensors from different vehicles. Currently, this demand remains largely unfulfilled due to a lack of systems that can handle such diverse demands efficiently. Vehicles are usually passive participants in data acquisition, each continuously reading and transmitting the same static set of sensors. However, in a multi-tenant setup with diverse data demands, each vehicle potentially needs to provide different data instead. We present a system that performs such vehicle-specific minimization of data acquisition by mapping individual data demands to individual vehicles. We collect personal data only after prior consent and fulfill the requirements of the GDPR. Non-personal data can be collected by directly addressing individual vehicles. The system consists of a software component natively integrated with a major automaker’s vehicle platform and a cloud platform brokering access to acquired data. Sensor readings are either provided via near real-time streaming or as recorded trip files that provide specific consistency guarantees. A performance evaluation with over 200,000 simulated vehicles has shown that our system can increase server capacity on-demand and process streaming data within 269 ms on average during peak load. The resulting architecture can be used by other automakers or operators of large sensor networks. Native vehicle integration is not mandatory; the architecture can also be used with retrofitted hardware such as OBD readers. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Performance modelling of replication protocols

PhD ThesisThis thesis is concerned with the performance modelling of data replication protocols. Data replication is used to provide fault tolerance and to improve the performance of a distributed system. Replication not only needs extra storage but also has an extra cost associated with it when performing an update. It is not always clear which algorithm will give best performance in a given scenario, how many copies should be maintained or where these copies should be located to yield the best performance. The consistency requirements also change with application. One has to choose these parameters to maximize reliability and speed and minimize cost. A study showing the effect of change in different parameters on the performance of these protocols would be helpful in making these decisions. With the use of data replication techniques in wide-area systems where hundreds or even thousands of sites may be involved, it has become important to evaluate the performance of the schemes maintaining copies of data. This thesis evaluates the performance of replication protocols that provide differ- ent levels of data consistency ranging from strong to weak consistency. The protocols that try to integrate strong and weak consistency are also examined. Queueing theory techniques are used to evaluate the performance of these protocols. The performance measures of interest are the response times of read and write jobs. These times are evaluated both when replicas are reliable and when they are subject to random breakdowns and repairs.Commonwealth Scholarshi