89 research outputs found

    The Application of the Internet of Things to Enhance Urban Sustainability

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    This article examines opportunities and challenges faced by planners when applying Internet of Things (IoT) as a tool to facilitate urban sustainable development in the context of the Smart Cities movement. As an important element in the Smart Cities concept, IoT is expected to enhance urban sustainability through the sensor network that detects and transmits environmental data. However, there are still various challenges that add a layer of difficulty to the process of using IoT to achieve this goal. The article first identifies the concept and relationship of three key background issues: Smart Cities, Internet of Things, and sustainability. Then the article investigates the challenges of using IoT technology to assist urban sustainability in various aspects. Next, the article proposes possible responses to those challenges through three fields of application: waste management, smart streetlights, and smart homes. It is of great importance for urban planners to understand the complexity of these challenges due to the interdisciplinary nature of such applications. Therefore, it is essential for the field of urban planning to collaborate with other sectors to better utilize IoT technologies towards sustainability.https://deepblue.lib.umich.edu/bitstream/2027.42/136581/1/Zhang_TheApplicationOfTheInternetOfThingsToEnhanceUrbanSustainability.pd

    DProvSQL: Accuracy-Aware Privacy Provenance Framework for Differentially Private SQL Engine

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    Recent years have witnessed the adoption of differential privacy (DP) in practical database query systems. Such systems, like PrivateSQL and FLEX, allow data analysts to query sensitive data while providing a rigorous and provable privacy guarantee. However, existing systems may use more privacy budgets than necessary in certain cases where different data analysts with different privilege levels ask a similar or even the same query. In light of this deficiency, we propose \oursystem, a fine-grained privacy provenance framework that tracks the privacy loss to each single data analyst and we build algorithms that make use of this framework to maximize the number of queries that could be answered. We implement \oursystem as a middleware between the data analysts and the existing differentially private SQL query answering systems. The empirical results on the TPC-H dataset show that our approach can answer around 4x more queries than the baseline approach on average with marginal performance overhead

    Preventing Inferences through Data Dependencies on Sensitive Data

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    Simply restricting the computation to non-sensitive part of the data may lead to inferences on sensitive data through data dependencies. Inference control from data dependencies has been studied in the prior work. However, existing solutions either detect and deny queries which may lead to leakage – resulting in poor utility, or only protects against exact reconstruction of the sensitive data – resulting in poor security. In this paper, we present a novel security model called full deniability. Under this stronger security model, any information inferred about sensitive data from non-sensitive data is considered as a leakage. We describe algorithms for efficiently implementing full deniability on a given database instance with a set of data dependencies and sensitive cells. Using experiments on two different datasets, we demonstrate that our approach protects against realistic adversaries while hiding only minimal number of additional non-sensitive cells and scales well with database size and sensitive data

    Recovery from Non-Decomposable Distance Oracles

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    A line of work has looked at the problem of recovering an input from distance queries. In this setting, there is an unknown sequence s∈{0,1}≀ns \in \{0,1\}^{\leq n}, and one chooses a set of queries y∈{0,1}O(n)y \in \{0,1\}^{\mathcal{O}(n)} and receives d(s,y)d(s,y) for a distance function dd. The goal is to make as few queries as possible to recover ss. Although this problem is well-studied for decomposable distances, i.e., distances of the form d(s,y)=∑i=1nf(si,yi)d(s,y) = \sum_{i=1}^n f(s_i, y_i) for some function ff, which includes the important cases of Hamming distance, ℓp\ell_p-norms, and MM-estimators, to the best of our knowledge this problem has not been studied for non-decomposable distances, for which there are important special cases such as edit distance, dynamic time warping (DTW), Frechet distance, earth mover's distance, and so on. We initiate the study and develop a general framework for such distances. Interestingly, for some distances such as DTW or Frechet, exact recovery of the sequence ss is provably impossible, and so we show by allowing the characters in yy to be drawn from a slightly larger alphabet this then becomes possible. In a number of cases we obtain optimal or near-optimal query complexity. We also study the role of adaptivity for a number of different distance functions. One motivation for understanding non-adaptivity is that the query sequence can be fixed and the distances of the input to the queries provide a non-linear embedding of the input, which can be used in downstream applications involving, e.g., neural networks for natural language processing.Comment: This work has been presented at conference The 14th Innovations in Theoretical Computer Science (ITCS 2023) and accepted for publishing in the journal IEEE Transactions on Information Theor

    Finite Volume Graph Network(FVGN): Predicting unsteady incompressible fluid dynamics with finite volume informed neural network

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    In recent years, the development of deep learning is noticeably influencing the progress of computational fluid dynamics. Numerous researchers have undertaken flow field predictions on a variety of grids, such as MAC grids, structured grids, unstructured meshes, and pixel-based grids which have been many works focused on. However, predicting unsteady flow fields on unstructured meshes remains challenging. When employing graph neural networks (GNNs) for these predictions, the message-passing mechanism can become inefficient, especially with denser unstructured meshes. Furthermore, unsteady flow field predictions often rely on autoregressive neural networks, which are susceptible to error accumulation during extended predictions. In this study, we integrate the traditional finite volume method to devise a spatial integration strategy that enables the formulation of a physically constrained loss function. This aims to counter the error accumulation that emerged in autoregressive neural networks during long-term predictions. Concurrently, we merge vertex-center and cell-center grids from the finite volume method, introducing a dual message-passing mechanism within a single GNN layer to enhance the message-passing efficiency. We benchmark our approach against MeshGraphnets for unsteady flow field predictions on unstructured meshes. Our findings indicate that the methodologies combined in this study significantly enhance the precision of flow field predictions while substantially minimizing the training time cost. We offer a comparative analysis of flow field predictions, focusing on cylindrical, airfoil, and square column obstacles in two-dimensional incompressible fluid dynamics scenarios. This analysis encompasses lift coefficient, drag coefficient, and pressure coefficient distribution comparison on the boundary layers

    Achieving Adversarial Robustness via Sparsity

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    Network pruning has been known to produce compact models without much accuracy degradation. However, how the pruning process affects a network's robustness and the working mechanism behind remain unresolved. In this work, we theoretically prove that the sparsity of network weights is closely associated with model robustness. Through experiments on a variety of adversarial pruning methods, we find that weights sparsity will not hurt but improve robustness, where both weights inheritance from the lottery ticket and adversarial training improve model robustness in network pruning. Based on these findings, we propose a novel adversarial training method called inverse weights inheritance, which imposes sparse weights distribution on a large network by inheriting weights from a small network, thereby improving the robustness of the large network

    Photooxidation of a twisted isoquinolinone

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    Understanding the oxidation mechanism and positions of twistacenes and twistheteroacenes under ambient conditions is very important because such knowledge can guide us to design and synthesize novel, larger stable analogues. Herein, we demonstrated for the first time that a twisted isoquinolinone can decompose under oxygen and light at room temperature. The as‐decomposed product 1 was fully characterized through conventional methods as well as single‐crystal structure analysis. Moreover, the physical properties of the as‐obtained product were carefully investigated and the possible formation mechanism was proposed

    Measuring and Mitigating Constraint Violations of In-Context Learning for Utterance-to-API Semantic Parsing

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    In executable task-oriented semantic parsing, the system aims to translate users' utterances in natural language to machine-interpretable programs (API calls) that can be executed according to pre-defined API specifications. With the popularity of Large Language Models (LLMs), in-context learning offers a strong baseline for such scenarios, especially in data-limited regimes. However, LLMs are known to hallucinate and therefore pose a formidable challenge in constraining generated content. Thus, it remains uncertain if LLMs can effectively perform task-oriented utterance-to-API generation where respecting API's structural and task-specific constraints is crucial. In this work, we seek to measure, analyze and mitigate such constraints violations. First, we identify the categories of various constraints in obtaining API-semantics from task-oriented utterances, and define fine-grained metrics that complement traditional ones. Second, we leverage these metrics to conduct a detailed error analysis of constraints violations seen in state-of-the-art LLMs, which motivates us to investigate two mitigation strategies: Semantic-Retrieval of Demonstrations (SRD) and API-aware Constrained Decoding (API-CD). Our experiments show that these strategies are effective at reducing constraints violations and improving the quality of the generated API calls, but require careful consideration given their implementation complexity and latency
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