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关键词： Computer science   Information storage and retrieval systems   Cloud computing   Information storage and retrieval systems--Technology   Information storage and retrieval systems--Design and construction  

摘要： We enter the era of cloud computing in the last decade, as many paradigm shifts are happening on how people write and deploy applications. Despite the advancement of cloud computing, data storage abstractions have not evolved much, causing inefficiencies in performance, cost, and security. This dissertation proposes a novel approach to make data storage efficient in the era of cloud computing by building new storage abstractions and systems that bridge the gap between cloud computing and data storage and simplify development. We build four systems to address four data inefficiencies in cloud computing. The first system, Grandet, solves the data storage inefficiency caused by the paradigm shift from upfront provisioning to a variety of pay-as-you-go cloud services. Grandet is an extensible storage system that significantly reduces storage costs for web applications deployed in the cloud. Under the hood, it supports multiple heterogeneous stores and unifies them by placing each data object at the store deemed most economical. Our results show that Grandet reduces their costs by an average of 42.4%, and it is fast, scalable, and easy to use. The second system, Unic, solves the data inefficiency caused by the paradigm shift from single-tenancy to multi-tenancy. Unic securely deduplicates general computations. It exports a cache service that allows cloud applications running on behalf of mutually distrusting users to memoize and reuse computation results, thereby improving performance. Unic achieves both integrity and secrecy through a novel use of code attestation, and it provides a simple yet expressive API that enables applications to deduplicate their own rich computations. Our results show that Unic is easy to use, speeds up applications by an average of 7.58x, and with little storage overhead. The third system, Lambdata, solves the data inefficiency caused by the paradigm shift to serverless computing, where developers only write core business logic, and cloud serv

关键词： Information technology   Pharmaceutical sciences   Computer science  

摘要： Using technology tools to enhance operations, including more efficient and effective communications with customers, is essential for all businesses. This use is especially the case in rural areas of developing countries. This study aimed to determine and understand factors that contribute to the underutilization of information technology by small retail pharmacies in the rural parish of St. Elizabeth in Jamaica. A qualitative single-case study method was used employing interviews, observations, and documents to collect data. A sample frame of 14 participants from 12 rural pharmacies was selected for open-ended questionnaire interviews. These participants met the criteria of being full-time employees with three or more years of experience having the positions of the owner, manager, pharmacist, or clerks. Five themes emerged from the data collected. In order of frequency of comments by interviewees, these were financial concerns (100%), technology acceptance (71%), digital divide (65%), information literacy (30%), and diffusion of technology (15%). These findings demonstrated the hierarchical and intertwined relationship that greatly challenges the adoption of technology in small pharmacies in rural St. Elizabeth, Jamaica. It can be concluded that the primary reason for the underutilization of technology was the lack of financial resources. Still, other factors, such as technology acceptance, digital divide, information literacy, and diffusion of technology, played a substantial related and connected role. More financial resources would help to mitigate the underutilization of technology as would focusing on lessening other associated factors. Future research using quantitative comparisons of metropolitan and rural areas; and state-run and private pharmacies may assist in gaining a better understanding of the underutilization of technology by pharmacies in rural St. Elizabeth, Jamaica. Keywords: technology acceptance (TAM), digital divide, information literacy, diffus

关键词： Decision-making   Artificial intelligence   DARPA   Computer science   Human-computer interaction   Intelligence  

摘要： The Defense Advanced Research Project Agency's (DARPA) mission is to make pivotal investments leading to research breakthroughs that support national security. DARPA artificial intelligence (AI) programs have emphasized the need for machines to perceive and interact with the world around them;to frame problems and to arrive at solutions and decisions based on reasoning;to implement those decisions, perhaps through consultation with a human or another machine;to learn;to explain the rationale for decisions;to adhere to rules of ethical behavior defined for humans;to adapt to dynamic environments;and, to do all of this in real-time. In short, DARPA has always been interested in AI frameworks that integrate AI and computer science technologies, and the application of those frameworks to DARPA-hard problems. In this article, we describe the significant role that DARPA has played in the establishment of AI, and introduce six articles that explore DARPA's Three Waves of AI.

关键词： Journalism   Information science   Computer science  

摘要： The spread of false and misleading news online can have offline impacts. These impacts range widely, including health, public opinion, and safety. While low veracity information is not necessarily a new occurrence, the scale at which it is produced and disseminated is. This production and dissemination scale is partial due to the low barrier to entry into the information ecosystem. Today, anyone can spread information by creating a blog or website which appears to be proper news source. These seemingly credible sources of information can then obtain wide attention due to social networks and the engagement-based algorithms that curate the media feeds in these networks. In turn, this lack of gate-keeping opens the media ecosystem up for malicious actors to spread targeted disinformation. Due to the scale of low veracity news, the main question asked in this thesis is: Can we automatically detect low veracity news articles? Specifically, in this thesis, we develop and examine two broad approaches to automatically detecting low veracity news articles. First, we learn from news article text. In this approach, we focus on creating features of high veracity and low veracity news articles through text-based feature engineering. This feature engineering process starts out as an exploration on fact-checked news article data, with the goal of creating features that are interpretable by the eventual human end-user. After an understanding of the feature space is gained, we transfer the methodology to higher-level concepts of news veracity, such as reliability and bias, in order to use large scale data in machine learning tasks. We then test the robustness of these machine learning models in a series of concept drift tests and adversarial attack tests. Second, we learn from news source behavior and relationships. In this approach, we explore content sharing behavior by both mainstream and alternative news sources. Specifically, we construct content sharing networks from our unstr

关键词： Fuzzing   Licenses   Virtual machining   Computer science   Blockchain   Ethereum   smart contract   fuzzing   software testing   Fuzzer   security vulnerability   gas consumption   atomicity violation   vulnerability triggering  

摘要： Ethereum is a kind of blockchain platform where developers may develop and run programs called smart contracts. It inherently relies on gas consumption within a specified allowance to constrain code execution, making every instruction along an execution path to be a location for raising an exception. In this paper, we present GasFuzzer, the first work in exploring the effects of gas allowance manipulation to expose gas-oriented exception security vulnerabilities. GasFuzzer consists of two phases. The first phase introduces a gas-greedy strategy to favor transactions having higher gas consumption for mutation to obtain test transactions with different gas consumptions. The second phase introduces a novel notion of fractional gas consumption coverage and a novel gas-leveling strategy. It applies them to mutate the gas allowances of some of these transactions resulting in the highest gas consumptions produced in the first phase followed by applying these allowance-mutated transactions together with those which remained non-mutated to fuzz test the smart contract. We report an evaluation of GasFuzzer via an experiment on 3170 real-world smart contracts deployed on the public Ethereum Blockchain between October 2017 and July 2019. The findings show that GasFuzzer with gas-greedy strategy can detect more Exceptions Disorder kind of security vulnerabilities (7 more cases) than the previous state-of-the-art black-box fuzzer, and GasFuzzer with gas-leveling strategy and gas coverage criterion can detect 6 additional cases of Exceptions Disorder security vulnerabilities, which is significant.

关键词： Computer science  

摘要： Driven by advancements in computing and sensing technology, many scientific projects started to generate a huge volume of data that reaches to petabytes in scale. Distributed and collaborative nature of these projects requires produced data to be streamed to geographically distributed locations in a timely manner to enable real-time (or near-realtime) processing. Thus, robust and predictable network performance is key to streamline end-to-end workflow execution of streaming projects. On the other hand, existing high-performance data transfer applications and services support “best-effort” Quality of Service(QoS) model, thus fail to sustain high transfer performance when transfer conditions (e.g.,dataset characteristics, background traffic, etc.) deviate from initial observations., making them ill-suited for streaming workflows with stringent performance requirements. In this thesis, we propose FStream to offer performance guarantees to time-sensitive streaming applications by continuously monitoring transfer performance and re-adjusting transfer settings to adapt to dynamic transfer conditions and sustain high transfer performance throughout the workflow execution. To achieve this goal in real-time, FStream employs online profiling to rapidly explore solution space of transfer settings and find the one that meets QoS requirements with minimal overhead. It also takes advantage of the long-running nature of streaming workflows and keeps track of past online profiling results to greatly reduce convergence time of future online profiling runs. We evaluated the performance of FStream by transferring several synthetic and real-world workloads using high-performance production networks and showed that it offers up to an order of magnitude performance improvement over state-of-the-art solutions.

关键词： Computer science  

摘要： There has been tremendous research and development of forensic tools for Microsoft Windows-based operating systems over the years. This research will explore mainstream Macintosh forensic tools available to law enforcement agencies for forensic imaging, and the analysis of Macintosh computers. Importantly, this research will assist investigators in choosing a forensic platform when looking for an option for processing Macintosh computers. This research will evaluate BlackBag Technologies BlackLight® 2019 R3 and its ability to process a computer running the latest macOS (Catalina version 10.15.4). It will assist investigators to determine if the features and functionality of BlackLight® meet their demands. Investigators seize a massive amount of data during even the simplest of investigations. Forensic software tools assist investigators in processing enormous amounts of data through automation and triaging artifacts deemed to be most relevant. Forensic tool validation is critical for use in criminal and civil court proceedings. This research will examine the effectiveness of BlackBag Technologies Macintosh forensic tools and the automated features enabling investigators to quickly identify and locate important artifacts. The demand for Macintosh computers has steadily increased over the last few years and the law enforcement community needs to be prepared and have the proper tools at their disposal when they inevitably need to examine a Macintosh computer. Conclusions from this research will help guide those looking for a Macintosh tool to determine if BlackLight® is right for them and helps fill the void with the lack of research regarding Macintosh forensic tools.

关键词： Clustering algorithms   Shape   Task analysis   Support vector machines   Indexes   Data models   Computer science   Clustering   clusters of arbitrary shapes   data stream   multiview   support vector (SV)  

摘要： This article studies a new problem of data stream clustering, namely, multiview data stream (MVStream) clustering. Although many data stream clustering algorithms have been developed, they are restricted to the single-view streaming data, and clustering MVStreams still remains largely unsolved. In addition to the many issues encountered by the conventional single-view data stream clustering, such as capturing cluster evolution and discovering clusters of arbitrary shapes under the limited computational resources, the main challenge of MVStream clustering lies in integrating information from multiple views in a streaming manner and abstracting summary statistics from the integrated features simultaneously. In this article, we propose a novel MVStream clustering algorithm for the first time. The main idea is to design a multiview support vector domain description (MVSVDD) model, by which the information from multiple insufficient views can be integrated, and the outputting support vectors (SVs) are utilized to abstract the summary statistics of the historical multiview data objects. Based on the MVSVDD model, a new multiview cluster labeling method is designed, whereby clusters of arbitrary shapes can be discovered for each view. By tracking the cluster labels of SVs in each view, the cluster evolution associated with concept drift can be captured. Since the SVs occupy only a small portion of data objects, the proposed MVStream algorithm is quite efficient with the limited computational resources. Extensive experiments are conducted to demonstrate the effectiveness and efficiency of the proposed method.

关键词： Computer science  

摘要： In this research a dual-stage attention-based recurrent neural network has been used, this model can capture long-term dependencies as long as temporal relationships between the inputs. Most of previous models had difficulty capturing these two at the same time. In order to show the results of this model, it has been applied to the five datasets that they have been used for time series prediction using other methods of prediction. By comparing the results of DARNN and this models, it shows it efficiency and accuracy.

关键词： Computer science  

摘要： Ransomware has become an increasing threat in the world today. Ransomware is a type of malware that infects a system and encrypts files forcing the user to pay a ransom via bitcoin or some other anonymous payment service to decrypt them. Much like other pieces of software, ransomware can change its behavior and processes over the time it is developed. We refer to similar releases of ransomware as a family. To understand the threat of different ransomware families, they must be examined to unveil the nature of their processes. Ransomware, like other types of malware, tries to conceal itself and its processes on the victim’s machine to ensure that it can accomplish its goal undetected. Many ransomware families utilize self-deletion of the malware’s executable to avoid analysis. This study focuses on the self-deletion aspect of ransomware families to compare and contrast the effectiveness of different forensic toolkit’s abilities to recover ransomware executables after self-deletion. We focus on samples from 12 different ransomware families