Publications
173 results found
Pietzuch PR, Migliavacca M, Eyers D, 2010, SEEP: Scalable and Elastic Event Processing (Poster), ACM/IFIP/USENIX 11th International Middleware Conference (Middleware’10)
Migliavacca M, Eyers D, Bacon J, et al., 2010, SEEP: Scalable and elastic event processing, Middleware'10 Posters and Demos Track, Middleware Posters'10
Continuous streams of event data are generated in many application domains including financial trading, fraud detection, website analytics and system monitoring. An open challenge in data management is how to analyse and react to large volumes of event data in real-time. As centralised event processing systems reach their computational limits, we need a new class of event processing systems that support deployments at the scale of thousands of machines in a cloud computing setting. In this poster we present SEEP, a novel architecture for event processing that can scale to a large number of machines and is elastic in order to adapt dynamically to workload changes. © 2010 ACM.
Wray S, Luk W, Pietzuch P, 2010, Run-time reconfiguration for a reconfigurable algorithmic trading engine, Pages: 163-166
In this paper we present an analysis of using run-time reconfiguration of reconfigurable hardware to modify trading algorithms during use. This provides flexibility in algorithm design, enabling the implementation to be reactive to changes in market conditions, increasing in performance. We study what can be achieved to reduce performance loss in algorithms while reconfiguration takes place, such as buffering information during this time. Our results show our average partial reconfiguration time is 0.002091 seconds, using historic highest market data rates would result in about 5,000 messages being missed or require buffering. This is the worst case scenario, normally the system would only require a fraction of messages. The reconfiguration time is acceptable if it is under the required limit by the user to prevent business performance suffering. © 2010 IEEE.
Pietzuch PR, Malet B, 2010, Resource Allocation across Multiple Cloud Data Centres, 8th International Workshop on Middleware for Grids, Clouds and e-Science (MGC’10)
Web applications with rich AJAX-driven user interfaces make asynchronous erver-side calls to switch application state. To provide the best user experience, the response time of these calls must be as low as possible. Since response timeis bounded by network delay, it can be minimised by placing application components closest to the network location of the majority of anticipated users. However, with a limited budget for hosting applications, developers need to se-lect data centre locations strategically. In practice, the best choice is di cult to achieve manually due to dynamic client workloads and e ects such as ash crowds.In this paper, we propose a cloud management middleware that automatically adjusts the placement of web application components across multiple cloud data centres. Based on observations and predictions of client request rates, it migrates application components between data centres. Our evaluation with two data centres and globally distributed clients on PlanetLab shows that our approach can decrease median client response times by 21% for a realistic multi-tierweb application.
Cadar C, Pietzuch P, Wolf AL, 2010, Multiplicity computing: A vision of software engineering for next-generation computing platform applications, Pages: 81-85
New technologies have recently emerged to challenge the very nature of computing: multicore processors, virtualized operating systems and networks, and data-center clouds. One can view these technologies as forming levels within a new, global computing platform. We aim to open a new area of research, called multiplicity computing, that takes a radically different approach to the engineering of applications for this platform. Unlike other efforts, which are largely focused on innovations within specific levels, multiplicity computing embraces the platform as a virtually unlimited space of essentially redundant resources. This space is formed as a whole from the cross product of resources available at each level in the platform, offering a "multiplicity" of end-to-end resources. We seek to discover fundamentally new ways of exploiting the combinatorial multiplicity of computational, communication, and storage resources to obtain scalable applications exhibiting improved quality, dependability, and security that are both predictable and measurable. Copyright 2010 ACM.
Pietzuch PR, Cadar C, Wolf A, 2010, Multiplicity Computing: A Vision of Software Engineering for Next-Generation Computing Platform Applications, FSE/SDP Workshop on the Future of Software Engineering Research (FoSER’10)
Tsoi KH, Tse AHT, Pietzuch P, et al., 2010, Programming framework for clusters with heterogeneous accelerators, ACM SIGARCH Computer Architecture News, Vol: 38, Pages: 53-59, ISSN: 0163-5964
<jats:p>We describe a programming framework for high performance clusters with various hardware accelerators. In this framework, users can utilize the available heterogeneous resources productively and efficiently. The distributed application is highly modularized to support dynamic system configuration with changing types and number of the accelerators. Multiple layers of communication interface are introduced to reduce the overhead in both control messages and data transfers. Parallelism can be achieved by controlling the accelerators in various schemes through scheduling extension. The framework has been used to support physics simulation and financial application development. We achieve significant performance improvement on a 16-node cluster with FPGA and GPU accelerators.</jats:p>
Bacon J, Pietzuch P, Moody K, et al., 2010, Foreword by the general and local arrangements chairs, Proceedings of the 4th ACM International Conference on Distributed Event-Based Systems, DEBS 2010
Song J, Ma T, Pietzuch P, 2010, Towards automated verification of autonomous networks: A case study in self-configuration, 2010 8th IEEE International Conference on Pervasive Computing and Communications Workshops, PERCOM Workshops 2010, Pages: 582-587
In autonomic networks, the self-configuration of network entities is one of the most desirable properties. In this paper, we show how formal verification techniques can verify the correctness of self-configuration. As a case study, we describe the configuration of physical cell identifiers (pels), a radio configuration parameter in cellular base stations. We provide formal models of pel assignment algorithms and their desired properties. We then demonstrate how the potential for conflicting pel assignments can be detected using model checking and resolved in the design stage. Through this case study, we argue that both simulation and verification should be adopted and highlight the potential of runtime verification approaches in this space. © 2010 IEEE.
Pietzuch PR, Routray R, Zhang R, et al., 2010, Policy Generation Framework for Large-Scale Storage Infrastructures, IEEE International Symposium on Policies for Distributed Systems and Networks (Policy’10)
Pietzuch PR, Papagiannis I, Migliavacca M, et al., 2010, Enforcing User Privacy in Web Applications using Erlang, W2SP 2010, Pages: 1-8
Social networking applications on the web handle the personal data of a large number of concurrently active users. These applications must comply with complexprivacy requirements, while achieving scalability and high performance. Applying constraints to the flow of data through such applications to enforce privacy policy is challenging because individual components process data belonging to manydifferent users.We introduce a practical approach for uniformly enforcing privacy requirements in such applications using the actor-based Erlang programming language. To isolate the personal data of users, we exploit Erlang’s inexpensive process model anduse Erlang’s message passing mechanism to add policy checks. We illustrate this approach by describing the architecture of a privacy-preserving message dispatcher in a micro-blogging service. Our performance evaluation of a prototype implementation shows that this approach can enforce finegrainedprivacy guarantees with a low performance overhead.
Pietzuch PR, Tsoi KH, Papagiannis I, et al., 2010, Accelerating Publish/Subscribe Matching on Reconfigurable Supercomputing Platforms, Many-Core and Reconfigurable Supercomputing Conference (MRSC’10), Pages: 1-4
A modular design is proposed and analyzed for accelerating the publish/subscribe matching algorithm in reconfigurable hardware. With help from a performance model, we demonstrate an optimized FPGA implementation which is scalable and efficient enough for many of today’s most demanding web and financial applications. Our design achieves 5.9 times speedup over software while consuming around 0.5%of power.
Migliavacca M, Papagiannis I, Eyers DM, et al., 2010, DEFCON: high-performance event processing with information security, Departmental Technical Report: 10/2, Publisher: Department of Computing, Imperial College London, 10/2
In finance and healthcare, event processing systems handlesensitive data on behalf of many clients. Guaranteeinginformation security in such systems is challengingbecause of their strict performance requirements in termsof high event throughput and low processing latency.We describe DEFCON, an event processing systemthat enforces constraints on event flows between eventprocessing units. DEFCON uses a combination of staticand runtime techniques for achieving light-weight isolationof event flows, while supporting efficient sharing ofevents. Our experimental evaluation in a financial dataprocessing scenario shows that DEFCON can provide informationsecurity with significantly lower processing latencycompared to a traditional approach.
Kalyvianaki E, Wiesemann W, Vu QH, et al., 2010, SQPR: stream query planning with reuse, Departmental Technical Report: 10/11, Publisher: Department of Computing, Imperial College London, 10/11
When users submit new queries to a distributedstream processing system (DSPS), a query planner must allocatephysical resources, such as CPU cores, memory and networkbandwidth, from a set of hosts to queries. Allocation decisionsmust provide the correct mix of resources required by queries,while achieving an efficient overall allocation to scale in thenumber of admitted queries. By exploiting overlap betweenqueries and reusing partial results, a query planner can conserveresources but has to carry out more complex planning decisions.In this paper, we describe SQPR, a query planner that targetsDSPSs in data centre environments with heterogeneous resources.SQPR models query admission, allocation and reuse as a singleconstrained optimisation problem and solves an approximate versionto achieve scalability. It prevents individual resources frombecoming bottlenecks by re-planning past allocation decisionsand supports different allocation objectives. As our experimentalevaluation in comparison with a state-of-the-art planner showsSQPR makes efficient resource allocation decisions, even with ahigh utilisation of resources, with acceptable overheads.
Migliavacca M, Papagiannis I, Eyers DM, et al., 2010, Distributed Middleware Enforcement of Event Flow Security Policy, 11th International Middleware Conference, Publisher: SPRINGER-VERLAG BERLIN, Pages: 334-354, ISSN: 0302-9743
Bacon J, Evans D, Eyers DM, et al., 2010, Enforcing End-to-End Application Security in the Cloud (Big Ideas Paper), 11th International Middleware Conference, Publisher: SPRINGER-VERLAG BERLIN, Pages: 293-+, ISSN: 0302-9743
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Wray S, Luk W, Pietzuch P, 2010, Exploring Algorithmic Trading in Reconfigurable Hardware, 21st IEEE International Conference on Application-Specific Systems, Architectures and Processors, Publisher: IEEE, ISSN: 2160-0511
Migliavacca M, Papagiannis I, Eyers DM, et al., 2010, DEFCon: High-Performance Event Processing with Information Security, USENIX Annual Technical Conference (ATC'10), Pages: 1-15
Routray R, Zhang R, Eyers DM, et al., 2010, Policy Generation Framework for Large-Scale Storage Infrastructures., IEEE POLICY 2010, Publisher: IEEE Computer Society, Pages: 65-72
Eyers DM, Routray R, Zhang R, et al., 2009, Towards a middleware for configuring large-scale storage infrastructures, Proceedings of the 7th International Workshop on Middleware for Grids, Clouds and e-Science, MGC'09 held at the ACM/IFIP/USENIX 10th International Middleware Conference
The rapid proliferation of cloud and service-oriented computing infrastructure is creating an ever increasing thirst for storage within data centers. Ideally management applications in cloud deployments should operate in terms of high-level goals, and not present specific implementation details to administrators. Cloud providers often employ Storage Area Networks (SANs) to gain storage scalability. SAN configurations have a vast parameter space, which makes them one of the most difficult components to configure and manage in a cloud storage offering. As a step towards a general cloud storage configuration platform, this paper introduces a SAN configuration middleware that aids management applications in their task of updating and troubleshooting heterogeneous SAN deployments. The middleware acts as a proxy between management applications and a central repository of SAN configurations. The central repository is designed to validate SAN configurations against a knowledge base of best practice rules across cloud deployments. Management applications contribute local SAN configurations to the repository, and also subscribe to proactive notifications for configurations now no longer considered safe.
Pu C, Gedik B, Etzion O, et al., 2009, Foreword by the program chairs, Proceedings of the 3rd ACM International Conference on Distributed Event-Based Systems, DEBS 2009
Kostić D, Pierre G, Junqueira F, et al., 2009, Euro-Par 2009 Parallel Processing: Introduction, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Vol: 5704 LNCS, ISSN: 0302-9743
Pietzuch PR, Eyers D, Robert B, et al., 2009, Event-Processing Middleware with Information Flow Control (Poster), Middleware '09 10th International Middleware Conference, Publisher: Springer-Verlag
Pietzuch PR, Migliavacca M, Bacon J, et al., 2009, Security in Multi-domain Event-based Systems, it - Information Technology (http://it-information-technology.de/), Vol: 51
Event-based systems give the potential for active information sharing. The vent-based paradigm, if used for event transport, provides loose coupling between components, many-to-many communication and mutual anonymity of event producers and event consumers. This communication style has been adopted enthusiastically for convenience of programming; particularly for financial processing, healthcare applications and sensor-based systems. But some data issensitive, and its visibility must be controlled carefully for personal and legal reasons. Our research projects have explored this space for some time, investigating application domains in which the event-based paradigm is appropriate yet where security is an issue. We discuss security issues for multi-domain,event-based systems, considering the requirements of applications and the risk associated with failure. We provide an overview of the state-of-the-art in secure event-based systems: research already carried out, work in progress and issuesstill to be addressed. This is of relevance to emerging large scale systems required by government and public bodies for domains such as healthcare, police, transport and environmental monitoring.
Pietzuch PR, Fiscato M, Vu QH, 2009, A Quality-Centric Data Model for Distributed Stream Management Systems, QDB 2009, Pages: 1-10
It is challenging for large-scale stream management systems to return always perfect results when processing data streams originating from distributed sources. Data sources and intermediate processing nodes may fail during the lifetime of a stream query. In addition, individual nodes may become overloaded due to processing demands. In practice, users have to accept incomplete or inaccuratequery results because of failure or overload. In this case, stream processing systems would benefit from knowing the impact of imperfect processing on data quality when making decisions about query optimisation and fault recovery. In addition, users would want to know how much the result quality was degraded.In this paper, we propose a quality-centric relational stream data model that can be used together with existing query processing methods over distributed data streams. Besides giving useful feedback about the quality of tuples to users, the model provides the distributed stream management system with information on how to optimise query processing and enhance fault tolerance. We demonstrate how our data model can be applied to an existing distributed stream management system. Our evaluation shows that it enables quality-aware load-shedding, while introducing only a small pertuple overhead.
Pietzuch PR, Schultz-Moeller NP, Migliavacca M, 2009, Distributed Complex Event Processing with Query Optimisation, International Conference on Distributed Event-Based Systems (DEBS’09), Publisher: ACM
The nature of data in enterprises and on the Internet is changing. Data used to be stored in a database rst and queried later. Today timely processing of new data, represented as events, is increasingly valuable. In many domains, complex event processing (CEP) systems detect patterns of events for decision making. Examples include processing of environmental sensor data, trades in nancial markets andRSS web feeds. Unlike conventional database systems, most current CEP systems pay little attention to query optimisation. They do not rewrite queries to more e cient representations or make decisions about operator distribution, limiting their overall scalability. This paper describes the Next CEP system that was especially designed for query rewriting and distribution. Event patterns are speci ed in a high-level query language and, before being translated into event automata, are rewritten ina more e cient form. Automata are then distributed across a cluster of machines fo detection scalability. We present algorithms for query rewriting and distributed placement. Our experiments on the Emulab test-bed show a signi cant improvement in system scalability due to rewriting and distribution.
Papagiannis I, Migliavacca M, Pietzuch P, et al., 2009, PrivateFlow: Decentralised Information Flow Control in Event Based Middleware (Demo)
Complex middleware frameworks are made out of interacting components which may include bugs. These frameworks are often extended to provide additional features by third-party extensions that may not be completely trusted and, as a result, compromise the security of the whole platform. Aiming to minimize these problems, we propose a demonstration of PrivateFlow, a publish/subscribe prototype supported by Decentralized Information Flow Control (DIFC). DIFC is a taint-tracking mechanism that can prevent components from leaking information. We will showcase a simple deployment of PrivateFlow that incorporates third-party untrusted components. In our demonstration, one of these components will try to leak sensitive information about the system's operation and it will fail once DIFC is activated.
Ho SW, Haddow T, Ledlie J, et al., 2009, Deconstructing Internet Paths: An Approach for AS-Level Detour Route Discovery, Eighth International workshop on Peer-To-Peer Systems IPTPS, Pages: 1-6
Bacon J, Eyers DM, Singh J, et al., 2008, Access control in publish/subscribe systems, Proceedings of the 2nd International Conference on Distributed Event-Based Systems, DEBS 2008, Pages: 23-24
Two convincing paradigms have emerged for achieving scalability in widely distributed systems: publish/subscribe communication and role-based, policy-driven control of access to the system by applications. A strength of publish/subscribe is its many-to-many communication paradigm and loose coupling of components, so that publishers need not know the recipients of their data and subscribers need not know the number and location of publishers. But some data is sensitive, and its visibility must be controlled carefully for personal and legal reasons. We describe the requirements of several application domains where the event-based paradigm is appropriate yet where security is an issue. Typical are the large-scale systems required by government and public bodies for domains such as healthcare, police, transport and environmental monitoring. We discuss how a publish/subscribe service can be secured; firstly by specifying and enforcing access control policy at the service API, and secondly by enforcing the security and privacy aspects of these policies within the service network itself. Finally, we describe an alternative to whole-message encryption, appropriate for highly sensitive and long-lived data destined for specific domains with varied requirements. We outline our investigations and findings from several research projects in these areas. Copyright 2008 ACM.
Ball N, Pietzuch P, 2008, Distributed content delivery using load-aware network coordinates, Proceedings of 2008 ACM CoNEXT Conference - 4th International Conference on Emerging Networking EXperiments and Technologies, CoNEXT '08
To scale to millions of Internet users with good performance, content delivery networks (CDNs) must balance requests between content servers while assigning clients to nearby servers. In this paper, we describe a new CDN design that associates synthetic load-aware coordinates with clients and content servers and uses them to direct content requests to cached content. This approach helps achieve good performance when request workloads and resource availability in the CDN are dynamic. A deployment and evaluation of our system on PlanetLab demonstrates how it achieves low request times with high cache hit ratios when compared to other CDN approaches.
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