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关键词： Bisac category: computers   distributed systems   general   computers   networking   general   computers   computer science  

ISBN: (数字)9781636393308 ISBN: (纸本)9781636393292;9781636393315

摘要： Theory is what remains true when technology is changing. So, it is important to know and master the basic concepts and the theoretical tools that underlie the design of the systems we are using today and the systems we will use tomorrow. This means that, given a computing model, we need to know what can be done and what cannot be done in that model. Considering systems built on top of an asynchronous read/write shared memory prone to process crashes, this monograph presents and develops the fundamental notions that are universal constructions, consensus numbers, distributed recursivity, power of the BG simulation, and what can be done when one has to cope with process anonymity and/or memory anonymity. Numerous distributed algorithms are presented, the aim of which is being to help the reader better understand the power and the subtleties of the notions that are presented. In addition, the reader can appreciate the simplicity and beauty of some of these algorithms.

ISBN: (纸本)9787111695844

关键词： Cognitive science   Computer science   Data science   Design   Developer experience   Human computer interaction  

摘要： Data science encompasses the most prominent collection of methods for creating scientific knowledge in the 21st century. Currently, data scientists must navigate a wide-ranging and often incoherent ecosystem of tools, in addition to organizing sociotechnical interactions with colleagues across many fields of expertise. This predicament motivates my thesis: The elements of data science work that are based in human expertise and social relationships must be integrated into existing programming workflows to create the developer experience that data scientists require to be successful. This dissertation supports my thesis by presenting three empirical studies and two tools. First, I investigated how professional data scientists teach novices about data science focused programming workflows, including how to adapt software development tools to their work, how to navigate the full depth of the stack of technologies that data science relies on, and how to use their tools to help communicate their findings. Then I explored how a team of academic data scientists repurposed the tools from their everyday data science work to create a data science course designed to reach traditionally underrepresented groups in computing. Finally, I examined how consulting data scientists interact with their clients, how their working relationships take them beyond well-characterized programming-oriented cycles, and how they achieve success by integrating designerly work into their data analysis process. These studies inspired me to develop two tools: 1. Datamations animates each step in a data analysis pipeline via transitions that show how rows, columns, and cells move within a data frame. 2. Tidy Data Tutor creates step-by-step interactive illustrations for a data analysis pipeline, so that every individual cell can be tracked. The main research findings of this dissertation are that data scientists adapt software engineering tools to fit into their own workflows, and that data scientists m

关键词： Containers   Mathematics   Computer science   Europe   Databases   Chemistry   COVID-19   E-assessment   cloud computing   distributed computing   artificial neural networks   human-computer interaction   user eXperience   COVID-19  

摘要： The pandemic has accelerated the process of digitization in many fields, highlighting some critical issues that have slowed the development of digital technologies in many areas. One of these is undoubtedly that of skills assessment, which on a digital platform is a more streamlined, reliable and faster process and allows some individuals from disadvantaged groups to be able to carry out the exam more easily. We present some strategies for enabling online remote secure written exams and their implementation through the open-source system LibreEOL. The system can be used for university exams (in presence or from remote locations) and training courses of all types to evaluate the effectiveness of learning in itinere, i.e., before, during and after a course, to provide quantitative data on training effectiveness. We outline the architecture of the services underpinning the system and the logical organisation of the various user roles and content relating to questions and exam delivery. We describe the algorithms that have allowed us to develop an environment that appears to be an essential aid both for teachers and students in light of the questionnaires conducted on students. The system is successfully used in the EchemTest, promoted by the European Chemistry Thematic Network, and allows comparison of chemistry training outcomes in different European countries. Despite the importance, it has taken on in the last two years due to the pandemic, such a system makes it possible to carry out a valuable skills assessment.

关键词： Synchronization   Switches   Automata   Computational modeling   Ports (computers)   Computer science   Network-on-chip   XML   Network-on-chip   formal model   model checking   finite state machine   starvation  

摘要： This work presents formal modeling of Network-on-Chip (NoC) considering detailed functional units of NoC. The intricate modeling of NoC router components like buffer, switch, and arbiter is accomplished using Finite State Machine (FSM). As in the case of a real NoC, parallel execution of these functional units is carried out by maintaining the synchronization between these functional units within a router and between each of the adjacent routers in the presented formal model. Important properties for the correctness of the proposed model are verified using a model checker. Implementing a detailed and a complete NoC model is a memory extensive operation while verifying with a model checker. We have introduced a concept of active windows to verify each router and its communication with the adjacent routers. The correctness of the model is checked by verifying the synchronization between NoC functional units and NoC routers, verifying progress in functional units, and verifying the successful transfer of packets. Verification of starvation freedom in an NoC router is also performed for round-robin arbiter and fixed-priority arbiter. Parallel threads are used in the experiments to reduce the verification time.

关键词： Yield stress   Metals   Aluminum   Software   Gold   Grain size   Deformation   Single crystals   Grain boundaries   Shear stress   Computer science   Mechanics   Physics  

摘要： BCC metals are commonly used throughout the world and understanding their deformation behavior, especially at the sub-grain level, is essential for their continued use in technological advancements. Correctly and confidently characterizing the active slip systems in BCC materials has been a difficult task throughout past research. The research described in this thesis utilizes high resolution digital image correlation (HRDIC) and relative displacement ratio (RDR) analysis to accurately characterize active slip systems in large grained BCC tantalum and provides new insights into dislocation nucleation sites, relative CRSS values for {110} and {112} slip systems, the correlation between GB transmission factors and strain gradients, the relative length of NBGZs, and slip transmission. A 99.99% pure tantalum oligo sample was sputtered with gold and remodeled to provide high resolution data points to be used in HRDIC. The high resolution of the gold remodeled samples combined with a RDR analysis made it possible to confidently identify active slip systems during tensile deformation at room temperature. One of the observations from this analysis was the discrepancy between the observed active slip systems and those predicted from a simple single-CRSS Schmid's Law. By considering the active systems observed in grains with a range of orientation, it was concluded that the {112} slip systems have a higher CRSS than the {110} by 6.7%. Independent CPFE simulations and experiments on single crystal samples of the same material, agreed with our findings establishing a range of increased CRSS for {112} of 3.9%-7.1%. These conclusions are compared with the small number of available estimates of the CRSS ratio, and lie in between the value of equal CRSS used by most modelers, and experimental estimates of 15-25% higher for {112}. The identified active slip systems were also used in the Luster and Morris equation to calculate each GBs transmissivity factor - an estimate of strain in

关键词： Computer science assessment   Concept maps   Middle school  

摘要： Concept Mapping has long been used in academic settings for various purposes but has been underutilized for assessment. Creating the concept map task and scoring the maps have been barriers to their widespread acceptance, but these difficulties are mitigated with automation and simple tools for the teacher to use. The aim of this work is to show that concept maps can be used effectively as computer science assessments in secondary schools. Ultimately, they can be used to measure student knowledge and to complement other forms of classroom assessments. We used the *** CS Discoveries Units 1-3 Curriculum taught in two newly trained and one veteran computer science teachers' classrooms to demonstrate that a concept map task can be used to achieve similar results to more traditional forms of assessment. The concept maps were collected using a web browser-based program and scored by another computer program using eight different scoring schemes created by the researchers. We compared these scores to assessments created by the teacher and an assessment created by the researchers that aligns with the objectives of the curriculum. The tools and concept map assessment method are appropriate for distance learning, and we found they offer an assessment alternative comparable to, and complementary to, existing methods.

关键词： Bisac category: computers   software development \u0026 engineering   computer graphics   computers   computer simulation   computers   computer science  

ISBN: (数字)9781636393278 ISBN: (纸本)9781636393261;9781636393285

摘要： This book explores the visualization of three-dimensional non-Euclidean spaces using raytracing techniques in Graphics Processing Unit (GPU). This is a trending topic in mathematical visualization that combines the mathematics areas of geometry and topology, with visualization concepts of computer graphics. Several conditions made this a special moment for such topic. On one hand, the development of mathematical research, computer graphics, and algorithms have provided the necessary theoretical framework. On the other hand, the evolution of the technologies and media allows us to be immersed in three-dimensional spaces using Virtual Reality. The content of this book serves both experts in the areas and students. Although this is a short book, it is self-contained since it considers all the ideas, motivations, references, and intuitive explanations of the required fundamental concepts.

ISBN: (纸本)9780231205023;9780231555807;0231555806

摘要： The works of African American authors and artists are too ofteninterpreted through the lens of authenticity. They are scrutinizedfor "positive" or &qu...

关键词： Elliptic curves   Blockchains   Computer science   Authentication   Prototypes   Performance gain   Companies   Zero-knowledge proofs   threshold issuance of credentials   threshold opening of credentials   multi-certifier model  

摘要： Authentication while maintaining anonymity when availing a service over the internet is a significant privacy challenge. Anonymous credentials (AC) address this by providing the user with a credential issued by a trusted entity that convinces the service provider ( $\mathcal {SP}$ ) that the user is authenticated but reveals no other information. The existing AC schemes assume a single trusted authority (certifier) that validates all the user attributes. In practice, however, a user may require different attributes to be attested by different certifiers. This means that the user has to get multiple credentials, increasing the burden on the $\mathcal {SP}$ who has to verify each one of them. Moreover, complete anonymity can be misused. We propose a decentralized threshold revocable anonymous credential (DTRAC) scheme over blockchains that supports - a) attestation of attributes by multiple certifiers, and b) anonymity revocation through a set of distributed openers, by integrating threshold opening to the state-of-the-art threshold anonymous credential issuance scheme, Coconut [35]. DTRAC generates a single credential on attributes that are attested by multiple certifiers, freeing the SP from the hassle of verifying multiple credentials. We analyze the security of DTRAC formally in the universal composability (UC) framework. We also implement a prototype on Ethereum using smart contracts and give a detailed analysis of its performance. We compare the verification time for credentials with attributes attested by multiple certifiers in both DTRAC and Coconut and see that in terms of execution time and gas consumption, DTRAC performs significantly better than Coconut. It also scales better, with the performance gain of DTRAC over Coconut increasing linearly with the number of certifiers.