there is a growing need for methods that can represent and query uncertain graphs. these uncertain graphs are often the result of an information extraction and integration system that attempts to extract an entity gra...
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ISBN:
(纸本)9781479934805
there is a growing need for methods that can represent and query uncertain graphs. these uncertain graphs are often the result of an information extraction and integration system that attempts to extract an entity graph or a knowledge graph from multiple unstructured sources [25], [7]. Such an integration typically leads to identity uncertainty, as different data sources may use different references to the same underlying real-world entities. Integration usually also introduces additional uncertainty on node attributes and edge existence. In this paper, we propose the notion of a probabilistic entity graph (PEG), a formal model that uniformly and systematically addresses these three types of uncertainty. A PEG is a probabilistic graph model that defines a distribution over possible graphs at the entity level. We introduce a general framework for constructing a PEG given uncertain data at the reference level and develop efficient algorithms to answer subgraph pattern matching queries in this setting. Our algorithms are based on two novel ideas: context-aware path indexing and reduction by join-candidates, which drastically reduce the query search space. A comprehensive experimental evaluation shows that our approach outperforms baseline implementations by orders of magnitude.
Given a set of facilities and a set of users, a reverse k nearest neighbors (RkNN) query q returns every user for which the query facility is one of the k-closest facilities. Due to its importance, RkNN query has rece...
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ISBN:
(纸本)9781479934805
Given a set of facilities and a set of users, a reverse k nearest neighbors (RkNN) query q returns every user for which the query facility is one of the k-closest facilities. Due to its importance, RkNN query has received significant research attention in the past few years. Almost all of the existing techniques adopt a pruning-and-verification framework. Regions-based pruning and half-space pruning are the two most notable pruning strategies. the half-space based approach prunes a larger area and is generally believed to be superior. Influenced by this perception, almost all existing RkNN algorithms utilize and improve the half-space pruning strategy. We observe the weaknesses and strengths of both strategies and discover that the regions-based pruning has certain strengths that have not been exploited in the past. Motivated by this, we present a new RkNN algorithm called SLICE that utilizes the strength of regions-based pruning and overcomes its limitations. Our extensive experimental study on synthetic and real data sets demonstrate that SLICE is significantly more efficient than the existing algorithms. We also provide a detailed theoretical analysis to analyze various aspects of our algorithm such as I/O cost, the unpruned area, and the cost of its verification phase etc. the experimental study validates our theoretical analysis.
Sludge is an intrinsic by-product of the Oil & Gas Industry, it is considered a hazardous waste and there are few technologies within the industry to process it under an environmentally sound protocol. Sludge to O...
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the proceedings contain 48 papers. the topics discussed include: hot-hardening: getting more out of your security settings;challenges and implications of verifiable builds for security-critical open-source software;cl...
the proceedings contain 48 papers. the topics discussed include: hot-hardening: getting more out of your security settings;challenges and implications of verifiable builds for security-critical open-source software;cloud radar: near real-time detection of security failures in dynamic virtualized infrastructures;android security framework: extensible multi-layered access control on android;towards a salable resource-driven approach for detecting repackaged android applications;a taste of tweets: reverse engineering twitter spammers;new models of cache architectures characterizing information leakage from cache side channels;interrupt-oriented bugdoor programming: a minimalist approach to bugdooring embedded systems firmware;uncovering network tarpits with degreaser;and network dialog minimization and network dialog diffing: two novel primitives for network security applications.
Off-the-shelf intrusion detection systems prove an ill fit for protecting industrial control systems, as they do not take their process semantics into account. Specifically, current systems fail to detect recent proce...
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ISBN:
(纸本)9781450330053
Off-the-shelf intrusion detection systems prove an ill fit for protecting industrial control systems, as they do not take their process semantics into account. Specifically, current systems fail to detect recent process control attacks that manifest as unauthorized changes to the configuration of a plant s programmable logic controllers (PLCs). In this work we present a detector that continuously tracks updates to corresponding process variables to then derive variablespecific prediction models as the basis for assessing future activity. Taking a specification-agnostic approach, we passively monitor plant activity by extracting variable updates from the devices network communication. We evaluate the capabilities of our detection approach with traffic recorded at two operational water treatment plants serving a total of about one million people in two urban areas. We show that the proposed approach can detect direct attacks on process control, and we further explore its potential to identify more sophisticated indirect attacks on field device measurements as well.
We demonstrate a simple set of interrupt-related vulnerability primitives that, despite being apparently innocuous, give attackers full control of a microcontroller platform. We then present a novel, minimalist approa...
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ISBN:
(纸本)9781450330053
We demonstrate a simple set of interrupt-related vulnerability primitives that, despite being apparently innocuous, give attackers full control of a microcontroller platform. We then present a novel, minimalist approach to constructing deniable bugdoors for microcontroller firmware, and contrast this approach withthe current focus of exploitation research on demonstrations of maximum computational power that malicious computation can achieve. Since the introduction of Return-oriented programming, an ever-increasing number of targets have been demonstrated to unintentionally yield Turing-complete computation environments to attackers controlling the target s various input channels, under ever more restrictive sets of limitations. Yet although modern OS defensive measures indeed require complex computations to bypass, this focus on maximum expressiveness of exploit programming models leads researchers to overlook other research directions for platforms that lack strong defensive measure but occur in mission-critical systems, namely, microcontrollers. In these systems, common exploiter goals such as sensitive code and data exfiltration or arbitrary code execution do not typically require complex computation;instead, a minimal computation is preferred and a simple set of vulnerability primitives typically suffices. We discuss examples of vulnerabilities and the new kinds of tools needed to avoid them in future firmware. Copyright 2014 ACM.
the proceedings contain 24 papers. the topics discussed include: new LEEPL technology;high-throughput parallel SPM for metrology, defect and mask inspection;multi-stencil character projection e-beam lithography - a fa...
ISBN:
(纸本)9781628412857
the proceedings contain 24 papers. the topics discussed include: new LEEPL technology;high-throughput parallel SPM for metrology, defect and mask inspection;multi-stencil character projection e-beam lithography - a fast and flexible way for high quality optical metamaterials;replicating micro-optical structures using soft embossing technique;14-nm photomask simulation sensitivity;aerial image simulation for partial coherent system withprogramming development in MATLAB;photomask CD and LER characterization using Mueller matrix spectroscopic ellipsometry;determination of line profiles on photomasks using DUV, EUV and X-ray scattering;overlay leaves litho: impact of non-litho processes on overlay and compensation;and lithography with Infrared illumination alignment for advanced BiCMOS backside processing.
Bounded model checking (BMC) has successfully been used for many practical program verification problems, but concurrency still poses a challenge. Here we describe a new approach to BMC of sequentially consistent C pr...
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ISBN:
(纸本)9783319088679;9783319088662
Bounded model checking (BMC) has successfully been used for many practical program verification problems, but concurrency still poses a challenge. Here we describe a new approach to BMC of sequentially consistent C programs using POSIX threads. Our approach first translates a multi-threaded C program into a nondeterministic sequential C program that preserves reachability for all round-robin schedules with a given bound on the number of rounds. It then re-uses existing high-performance BMC tools as backends for the sequential verification problem. Our translation is carefully designed to introduce very small memory overheads and very few sources of nondeterminism, so that it produces tight SAT/SMT formulae, and is thus very effective in practice: our prototype won the concurrency category of SV-COMP14. It solved all verification tasks successfully and was 30x faster than the best tool with native concurrency handling.
Location-related data has a tremendous impact in many applications of high societal relevance and its growing volume from heterogeneous sources is one true example of a Big Data [1]. An inherent property of any spatio...
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ISBN:
(纸本)9781479925568
Location-related data has a tremendous impact in many applications of high societal relevance and its growing volume from heterogeneous sources is one true example of a Big Data [1]. An inherent property of any spatio-temporal dataset is uncertainty due to various sources of imprecision. this tutorial provides a comprehensive overview of the different challenges involved in managing uncertain spatial and spatio-temporal data and presents state-of-the-art techniques for addressing them.
We propose techniques for exploratory search in large databases. the goal is to provide new functionality that aids users in homing in on the right query conditions to find what they are looking for. Query refinement ...
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ISBN:
(纸本)9781479925568
We propose techniques for exploratory search in large databases. the goal is to provide new functionality that aids users in homing in on the right query conditions to find what they are looking for. Query refinement proceeds interactively by repeatedly consulting the user to manage query conditions. this process is characterized by three key challenges: (1) dealing with incomplete and imprecise user input, (2) keeping user effort low, and (3) guaranteeing interactive system response time. We address the first two challenges with a probability-based framework that guides the user to the most important query conditions. To recover from input errors, we introduce the notion of sensitivity and propose efficient algorithms for identifying the most sensitive user input, i.e., those inputs that had the greatest influence on the query results. For the third challenge, we develop techniques that can deliver estimates of the required probabilities within a given hard realtime limit and are able to adapt automatically as the interactive query refinement proceeds.
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