Column Sketches Hentschel, Brian; Kester, Michael S.; Idreos, Stratos
Proceedings of the 2018 International Conference on Management of Data,
05/2018
Conference Proceeding
Odprti dostop
While numerous indexing and storage schemes have been developed to address the core functionality of predicate evaluation in data systems, they all require specific workload properties (query ...selectivity, data distribution, data clustering) to provide good performance and fail in other cases. We present a new class of indexing scheme, termed a Column Sketch, which improves the performance of predicate evaluation independently of workload properties. Column Sketches work primarily through the use of lossy compression schemes which are designed so that the index ingests data quickly, evaluates any query performantly, and has small memory footprint. A Column Sketch works by applying this lossy compression on a value-by-value basis, mapping base data to a representation of smaller fixed width codes. Queries are evaluated affirmatively or negatively for the vast majority of values using the compressed data, and only if needed check the base data for the remaining values. Column Sketches work over column, row, and hybrid storage layouts.
We demonstrate that by using a Column Sketch, the select operator in modern analytic systems attains better CPU efficiency and less data movement than state-of-the-art storage and indexing schemes. Compared to standard scans, Column Sketches provide an improvement of 3x-6x for numerical attributes and 2.7x for categorical attributes. Compared to state-of-the-art scan accelerators such as Column Imprints and BitWeaving, Column Sketches perform 1.4 - 4.8× better.
This paper examines event-triggered data transmission in distributed networked control systems with packet loss and transmission delays. We propose a distributed event-triggering scheme, where a ...subsystem broadcasts its state information to its neighbors only when the subsystem's local state error exceeds a specified threshold. In this scheme, a subsystem is able to make broadcast decisions using its locally sampled data. It can also locally predict the maximal allowable number of successive data dropouts (MANSD) and the state-based deadlines for transmission delays. Moreover, the designer's selection of the local event for a subsystem only requires information on that individual subsystem. Our analysis applies to both linear and nonlinear subsystems. Designing local events for a nonlinear subsystem requires us to find a controller that ensures that subsystem to be input-to-state stable. For linear subsystems, the design problem becomes a linear matrix inequality feasibility problem. With the assumption that the number of each subsystem's successive data dropouts is less than its MANSD, we show that if the transmission delays are zero, the resulting system is finite-gain Lp stable. If the delays are bounded by given deadlines, the system is asymptotically stable. We also show that those state-based deadlines for transmission delays are always greater than a positive constant.
This textbook addresses students, professionals, lecturers and researchers interested in software product line engineering. With more than 100 examples and about 150 illustrations, the authors ...describe in detail the essential foundations, principles and techniques of software product line engineering.
The authors are professionals and researchers who significantly influenced the software product line engineering paradigm and successfully applied software product line engineering principles in industry. They have structured this textbook around a comprehensive product line framework.
Software product line engineering has proven to be the paradigm for developing a diversity of software products and software-intensive systems in shorter time, at lower cost, and with higher quality. It facilitates platform-based development and mass customisation. The authors elaborate on the two key principles behind software product line engineering: (1) the separation of software development in two distinct processes, domain and application engineering; (2) the explicit definition and management of the variability of the product line across all development artefacts.
As a student, you will find a detailed description of the key processes, their activities and underlying techniques for defining and managing software product line artefacts. As a researcher or lecturer, you will find a comprehensive discussion of the state of the art organised around the comprehensive framework. As a professional, you will find guidelines for introducing this paradigm in your company and an overview of industrial experiences with software product line engineering.
Apache Hive Camacho-Rodríguez, Jesús; Chauhan, Ashutosh; Gates, Alan ...
Proceedings of the 2019 International Conference on Management of Data,
06/2019
Conference Proceeding
Apache Hive is an open-source relational database system for analytic big-data workloads. In this paper we describe the key innovations on the journey from batch tool to fully fledged enterprise data ...warehousing system. We present a hybrid architecture that combines traditional MPP techniques with more recent big data and cloud concepts to achieve the scale and performance required by today's analytic applications. We explore the system by detailing enhancements along four main axis: Transactions, optimizer, runtime, and federation. We then provide experimental results to demonstrate the performance of the system for typical workloads and conclude with a look at the community roadmap.
Network and Parallel Computing Park, James J; Zomaya, Albert Y; Yeo, Sang-Soo ...
2012, 2015-03-18, Letnik:
7513
eBook, Conference Proceeding, Book
Recenzirano
This book constitutes the refereed post-proceedings of the 9th IFIP International Conference on Network and Parallel Computing, NPC 2012, held in Gwangju, Korea, in September 2012. The 38 papers ...presented were carefully reviewed and selected from 136 submissions. The papers are organized in the following topical sections: algorithms, scheduling, analysis, and data mining; network architecture and protocol design; network security; paralel, distributed, and virtualization techniques; performance modeling, prediction, and tuning; resource management; ubiquitous communications and networks; and web, communication, and cloud computing. In addition, a total of 37 papers selected from five satellite workshops (ATIMCN, ATSME, Cloud&Grid, DATICS, and UMAS 2012) are included.
Amazon Aurora Verbitski, Alexandre; Gupta, Anurag; Saha, Debanjan ...
Proceedings of the 2018 International Conference on Management of Data,
05/2018
Conference Proceeding
Amazon Aurora is a high-throughput cloud-native relational database offered as part of Amazon Web Services (AWS). One of the more novel differences between Aurora and other relational databases is ...how it pushes redo processing to a multi-tenant scale-out storage service, purpose-built for Aurora. Doing so reduces networking traffic, avoids checkpoints and crash recovery, enables failovers to replicas without loss of data, and enables fault-tolerant storage that heals without database involvement. Traditional implementations that leverage distributed storage would use distributed consensus algorithms for commits, reads, replication, and membership changes and amplify cost of underlying storage. In this paper, we describe how Aurora avoids distributed consensus under most circumstances by establishing invariants and leveraging local transient state. Doing so improves performance, reduces variability, and lowers costs.
In this paper, we study the stability of networked control systems (NCSs) that are subject to time-varying transmission intervals, time-varying transmission delays, and communication constraints. ...Communication constraints impose that, per transmission, only one node can access the network and send its information. The order in which nodes send their information is orchestrated by a network protocol, such as, the Round-Robin (RR) and the Try-Once-Discard (TOD) protocol. In this paper, we generalize the mentioned protocols to novel classes of so-called "periodic" and "quadratic" protocols. By focusing on linear plants and controllers, we present a modeling framework for NCSs based on discrete-time switched linear uncertain systems. This framework allows the controller to be given in discrete time as well as in continuous time. To analyze stability of such systems for a range of possible transmission intervals and delays, with a possible nonzero lower bound, we propose a new procedure to obtain a convex overapproximation in the form of a polytopic system with norm-bounded additive uncertainty. We show that this approximation can be made arbitrarily tight in an appropriate sense. Based on this overapproximation, we derive stability results in terms of linear matrix inequalities (LMIs). We illustrate our stability analysis on the benchmark example of a batch reactor and show how this leads to tradeoffs between different protocols, allowable ranges of transmission intervals and delays. In addition, we show that the exploitation of the linearity of the system and controller leads to a significant reduction in conservatism with respect to existing approaches in the literature.
Hybrid systems describe the interaction of software, modeled by finite-state systems such as finite-state machines, with the physical world, described by infinite-state systems such as differential ...equations. Verification and Control of Hybrid Systems provides a unique systematic exposition of several classes of hybrid systems, admitting symbolic models along with the relationships between them. The text outlines several key verification and control synthesis results for hybrid systems, guided by the concept of bisimulation, and illustrated by numerous examples. The book is divided into four parts: Part I presents basic concepts centered on a notion of system that is general enough to describe finite-state, infinite-state, and hybrid systems. Part II discusses the ways in which systems relate to other systems, such as behavioral inclusion/equivalence and simulation/bisimulation, using these relationships to study verification and control synthesis problems for finite-state systems. Part III draws inspiration from timed automata to present several classes of hybrid systems, with richer continuous dynamics, that can be related to finite-state symbolic systems. Once such relationships are established, verification and control synthesis problems for these hybrid systems can be immediately solved by resorting to the techniques described in Part II for finite-state systems. Part IV follows the same strategy by generalizing simulation/bisimulation relationships to approximate simulation/bisimulation relationships that can be used for a wider class of hybrid systems. This comprehensive treatment will appeal to researchers, engineers, computer scientists, and graduate students in the areas of formal methods, verification, model checking, and control and will undoubtedly inspire further study of the specialized literature.
Attacks against computer systems can cause considerable economic or physical damage. High-quality development of security-critical systems is difficult, mainly because of the conflict between ...development costs and verifiable correctness. Jürjens presents the UML extension UMLsec for secure systems development. It uses the standard UML extension mechanisms, and can be employed to evaluate UML specifications for vulnerabilities using a formal semantics of a simplified fragment of UML. Established rules of security engineering can be encapsulated and hence made available even to developers who are not specialists in security. As one example, Jürjens uncovers a flaw in the Common Electronic Purse Specification, and proposes and verifies a correction. With a clear separation between the general description of his approach and its mathematical foundations, the book is ideally suited both for researchers and graduate students in UML or formal methods and security, and for advanced professionals writing critical applications. Written for:Researchers, advanced professionals, graduatesKeywords:System DesignSystem DevelopmentSystem SecurityUMLUMLsec
In this work, we focus on model predictive control of nonlinear systems subject to data losses. The motivation for considering this problem is provided by wireless networked control systems and ...control of nonlinear systems under asynchronous measurement sampling. In order to regulate the state of the system towards an equilibrium point while minimizing a given performance index, we propose a Lyapunov-based model predictive controller which is designed taking data losses explicitly into account, both in the optimization problem formulation and in the controller implementation. The proposed controller allows for an explicit characterization of the stability region and guarantees that this region is an invariant set for the closed-loop system under data losses, if the maximum time in which the loop is open is shorter than a given constant that depends on the parameters of the system and the Lyapunov-based controller that is used to formulate the optimization problem. The theoretical results are demonstrated through a chemical process example.
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