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关键词： Business administration   Computer science  

摘要： For small businesses, returns on investment are a top priority. To ensure that an organization has the proper systems in place, managers and decision-makers should understand the barriers that will benefit the company's interest. In this paper, we discuss the barriers that were identified by employees that must be addressed when considering the implementation of the Internet of Things (IoT). Training, internet security, and social engineering are all barriers that must be addressed to prevent social engineering and system breaches. The challenge for Small Medium Enterprises (SME) is to decide the appropriate IoT devices, the need to know, user policies, and behavioral protocols to best support the distributed workforce in how, where, and when they perform their jobs. To build and implement a system can take substantial planning, but it will be well worth the effort. With a robust business framework for network infrastructure, SME can benefit from both IoT implementation to maximize the proficiency and productivity of its employees. The research gathered during this research dug deeper to identify barriers and to focus on understanding why companies choose not to update or upgrade systems other than the "just because" decisions. Lastly, as the barriers were reviewed, it is wise to note that everyone within an organization must be trained on how to maintain information security and how IoTs devices are everyone's responsibility. Whether it is an employee browsing social media on the cell phone, the custodian disposing of sensitive files, protecting client's data via telephone calls, or everyday shoulder surfing. Once barriers are identified, solutions can be put into place to ensure the organizations' workflow is progressing efficiently and effectively.

关键词： Cognitive psychology   Computer science  

摘要： The digital typesetting of mathematics can present many challenges to users, especially those of novice to intermediate experience levels. Through a series of experiments, we show that two models used to represent mathematical structure in these typesetting applications, the 1-dimensional structure based model and the 2-dimensional freeform model, cause interference with users' working memory during the process of transcribing mathematical content. This is a notable finding as a connection between working memory and mathematical performance has been established in the literature. Furthermore, we find that elements of these models allow them to handle various types of mathematical notation with different degrees of success. Notably, the 2-dimensional freeform model allows users to insert and manipulate exponents with increased efficiency and reduced cognitive load and working memory interference while the 1-dimensional structure based model allows for handling of the fraction structure with greater efficiency and decreased cognitive load.

关键词： Computer science  

摘要： Most current authentication mechanisms rely on static initial verification of the user; however, such authentication mechanisms do not verify user identities on already unlocked systems. This thesis presents a continuous authentication mechanism that constantly examines user’s keystroke timing dynamics to assess the user’s identity. This mechanism preserves the privacy of the user by only utilizing the key press timings without storing information regarding which keys were pressed. It implements two one-class classifiers, only utilizing genuine user samples for training the model, and thereby mitigates adversarial inclusion of impostor data in the model. The data utilized in this pilot study consists of timing information from 20 users. One-class classification was performed independently for all the *** results show that in less than 85 characters, the performance results include a False Acceptance Rate (FAR) as low as 0.6% and a False Rejection Rate (FRR) as low as 1%.The overall implication of this work is that a slightly complex model is required to achieve good performance results when excluding the keys pressed by the user for classification.

关键词： Computer science  

摘要： Since the broad application of Magnetic Resonance Imaging (MRI) in the clinic, faster data acquisition against the physical and physiological constraints has been the subject of intense experimental research and theoretical work. Among these efforts, parallel imaging uses multiple receiver elements to exploit the explicit redundancy of the MR data, which can achieve an aggressive under-sampling rate and hence reduced acquisition time. Unwillingly, it leads to the time-consuming post-processing procedure of image reconstruction instead. In this thesis, we propose to leverage the benefit of cloud computing to address the speeding issue. Based on a pay-per-use manner, a clinic with low computational power can easily outsource the computational-intensive tasks of image reconstruction to Cloud Service Providers (CSPs). However, the privacy concerns with outsourcing patients' private data to public cloud servers are ignited and hinder those practitioners from enjoying the benefits of cloud computing. Specifically, we explore the problem of privacy-preserving outsourcing the image reconstruction process in a calibration-less parallel imaging reconstruction method, termed simultaneous auto-calibrating and k-space estimation (SAKE). SAKE is one of the state-of-art algorithms in clinical implementation, which structure an under-sampled, multi-channel data-set in the k-space domain into a single data matrix. The reconstruction can then be formulated as a structured low-rank matrix completion problem. This thesis is seeking to enable a clinic to outsource the most computationally-intensive tasks in SAKE of the resource-abundant cloud servers, taking consideration of both the factors of security and efficiency. In particular, two different protocols are put forward in SecSAKE, with extra emphasis on privacy and efficiency, respectively. The first protocol we propose can enforce a low-complexity matrix transformation over the data in the k-space domain on the clinic end. The clin

关键词： Computer science   approximation   computational geometry   meshing   nearest-neighbor search   sampling   Voronoi  

摘要： Geometric approximation of multi-dimensional data sets is an essential algorithmic component for applications in machine learning, computer graphics, and scientific computing. This dissertation promotes an algorithmic sampling methodology for a number of fundamental approximation problems in computational geometry. For each problem, the proposed sampling technique is carefully adapted to the geometry of the input data and the functions to be approximated. In particular, we study proximity queries in spaces of constant dimension and mesh generation in 3D. We start with polytope membership queries, where query points are tested for inclusion in a convex polytope. Trading-off accuracy for efficiency, we tolerate one-sided errors for points within an epsilon-expansion of the polytope. We propose a sampling strategy for the placement of covering ellipsoids sensitive to the local shape of the polytope. The key insight is to realize the samples as Delone sets in the intrinsic Hilbert metric. Using this intrinsic formulation, we considerably simplify state-of-the-art techniques yielding an intuitive and optimal data structure. Next, we study nearest-neighbor queries which retrieve the most similar data point to a given query point. To accommodate more general measures of similarity, we consider non-Euclidean distances including convex distance functions and Bregman divergences. Again, we tolerate multiplicative errors retrieving any point no farther than (1+epsilon) times the distance to the nearest neighbor. We propose a sampling strategy sensitive to the local distribution of points and the gradient of the distance functions. Combined with a careful regularization of the distance minimizers, we obtain a generalized data structure that essentially matches state-of-the-art results specific to the Euclidean distance. Finally, we investigate the generation of Voronoi meshes, where a given domain is decomposed into Voronoi cells as desired for a number of important solvers in

关键词： Computer science  

关键词： Computer science  

摘要： In this dissertation we investigated the security of Bluetooth Low Energy (BLE) technology, in particular the beacon systems used to identify geolocation of the users. The vulnerabilities of the current BLE beacon systems were analyzed and an attack application for exploiting such a vulnerability was developed. Three machine learning techniques are developed for identifying the signals of existing BLE beacons and distinguishing them from the those from attackers. To improve the identification, three filtering techniques are analyzed for their performance when working with those machine learning techniques. A new BLE protocol with PKI authentication features for Bluetooth 5.0 was proposed and developed for defending the BLE beacons systems and BLE system in general. Its performance was evaluated on a prototype system and was acceptable for real-time applications. Integrating the new BLE protocol and BLE Beacon Defense techniques into the secure data delivery to right location system was also discussed.

关键词： Computer science  

摘要： Security threats against computing systems continue to proliferate, motivating new approaches for detection and mitigation. Though promising, many recently proposed defense techniques involve significant trade-offs that hinder their widespread adop- tion. While software-based defenses incur large penalties in terms of performance, hardware-supported solutions entail costly microarchitectural changes or necessitate compromises in terms of detection accuracy. To address these limitations, this dissertation proposes lightweight hardware support to provide enhanced security with significantly reduced performance cost relative to existing proposals. This research encompasses three novel security architectures, which address the challenges of dynamic malware detection, information flow tracking, and emerging side channel attacks against simultaneous multithreading (SMT) processors. The first of these proposals, called LightWatch, is a two-level malware detection framework that combines the benefits of hardware and software detectors while avoiding their limitations. Specifically, when used to enhance malware detection based on dynamic information flow tracking (DIFT), LightWatch features low mean performance overhead relative to native execution (14% or less), high detection sensitivity (97.5% of malicious execution epochs invoke a deterministic second-layer detector) and good usability (no false positives at the last layer of detection). An analytical model also demonstrates the application of LightWatch to reduce the performance cost of network-based intrusion detection systems. In addition to preserving performance in generalized computing environments, the LightWatch detection model can be extended to address the unique security needs of real-time systems. LATCH, the second system described in this dissertation, exploits the observation that information flows under DIFT exhibit strong temporal locality, with typical applications manipulating tracked data during limite

关键词： Classical studies   Rhetoric  

摘要： The purpose of this study is to examine the political culture of the Greek North Pontic cities of Olbia and Chersonesos through a rhetorical analysis of the honorary decrees passed by their respective ekklesiai during the Long Hellenistic Age (third century BCE until the mid-third century CE). The study seeks to achieve two main goals: to examine these decrees to understand the political framework of the two cities; and to understand the relationship between the elite recipients of the honors and the demos that awarded them. This investigation employs evidence from early fourth century BCE until the incorporation of the two cities into Roman province of Lower Moesia—during reign of the Emperor Hadrian. The thesis examines the decrees as texts and moves from the macro to the micro—from the institutional, social, and political framework of the two cities; to the ideas and values they espouse; and to the semantic and syntactic choices made by each composer of a decree. The study uses the additional evidence of the ancient commentators on rhetoric in order not only to recognize, but also to understand the choices made by each text’s author. These ancient commentators include: Aristotle, Cicero, Quintilian, and the progymnasmata, contemporary handbooks on rhetoric. It is the final contention of this study that the decrees are ultimately products of a rhetorical education that only the wealthy could afford. The selected epigraphical evidence of honorary decrees from the Greek cities of Olbia and Chersonesos indicate that these Hellenistic democratic poleis were, in fact, de facto oligarchies throughout the examined period.

关键词： computer science   primary school   programming   propedeutics of programming   Kodu Game Lab  

摘要： The article presents the research results on the development of methodological approaches to the propaedeutics programming in primary school using Kodu Game Lab environment. The authors have considered a variety of current trends in primary education programming, and in addition,connection between learning programming with the development of computer thinking, the formation of a "new literacy" and the achievement of the results of primary education. The authors identify seven methodological aspects of using Kodu Game Lab and give examples of their implementation. In addition, the article takes into account the lack of sufficient statistical support for the analysis of the effectiveness of the implementation of the developed approaches and formulates further ways of research. But also brings the arguments in favor of the use of the above methodological approaches.