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关键词： Computer science   Constructivism   Education   Math   Modulo   Modulus  

摘要： The modulo operator is a simple mathematical concept that is almost universally taught in early computer science. While remainders are introduced in elementary mathematics curricula, the modulo operator is generally not discussed in K-12 mathematics and the concept of remainders receives little attention throughout middle and high school mathematics coursework. This thesis examines what prior knowledge high school computer science students utilize when challenged with a story problem whose ideal solution involves using the modulo operator in assigning objects to bins. In this study, students provided plain English solutions to isomorphic versions of an open-ended problem statement before and after formal instruction about the modulo operator. Solutions were qualitatively tagged for strategies and terminology used, and solution correctness was assessed using an adapted scale based on the ''Structure of the Observed Learning Outcome'' (SOLO) taxonomy. A mixed-methods analysis strategy was used to provide insight into how students approached these problems and how their answers changed after instruction. Students demonstrated a wide range of strategies in the pretest, but no pretest solutions contained direct indicators of students leveraging prior knowledge of the modulo operator or the concept of remainders. However, students did reveal a natural tendency to rely on concepts related to conditional logic and described methods of wrapping back to the first bin, a behavior implemented by using the modulo operator. Posttest results showed significantly greater usage of remainders and modulo operator concepts, and posttest answers were significantly more sophisticated relative to the SOLO taxonomy. Thus, computer science instructors should remember that the applicative use of the modulo operator may appear unfamiliar to their students when seen for the first time. However, instructors may find the context of continually wrapping or cycling back to a beginning more natural

关键词： Convergence   Neural networks   Optimization   Scalability   Computer science   Approximation error   AWGN   Regularized image reconstruction   plug-and-play priors   deep learning   regularization parameter  

摘要： Plug-and-play priors (PnP) is a broadly applicable methodology for solving inverse problems by exploiting statistical priors specified as denoisers. Recent work has reported the state-of-the-art performance of PnP algorithms using pre-trained deep neural nets as denoisers in a number of imaging applications. However, current PnP algorithms are impractical in large-scale settings due to their heavy computational and memory requirements. This work addresses this issue by proposing an incremental variant of the widely used PnP-ADMM algorithm, making it scalable to problems involving a large number measurements. We theoretically analyze the convergence of the algorithm under a set of explicit assumptions, extending recent theoretical results in the area. Additionally, we show the effectiveness of our algorithm with nonsmooth data-fidelity terms and deep neural net priors, its fast convergence compared to existing PnP algorithms, and its scalability in terms of speed and memory.

关键词： Coding   Gender gap   Middle school   Project Lead the Way  

摘要： Women are underrepresented in the field of computer science. The presence offemale computer scientists has changed over time, with a downward trend in the past fewdecades, with only 18% of women compared to men earning their degrees in computerscience. Increasing the numbers of female students who pursue computer science notonly will lead to gender parity but will help fill the projected job openings in computerscience. Based on the high school enrollment in Advanced Placement Computer Science,the gender disparity is present at the high school level in District X. Research wastherefore conducted to explore how computer science experiences in lower gradesinfluence male and female students’ interest in the subject. Numerous studies at thehigher education level have indicated that societal and personal factors contribute towomen’s lack of interest in computer science (CS), in particular low self-efficacy, andlack of a sense of belonging. However, studies have not been conducted that specificallytarget middle school females and the relationship among factors including CSexperiences in elementary grades, self-efficacy, belonging or acceptance in a group, andinterest in computer science. The purpose of this study was to examine the factors thatled to the gender gap in computer science enrollment in the district. The study wasdesigned to determine the impact the computer science Project Lead the Way course hason male and female eighth graders. The findings revealed that the course had a positiveimpact on the students who participated in the study, but this sample was notrepresentative of the whole class. The PLTW CS course cannot yet to be said to increasefemale interest in computer science, but indications from the data reveal it may if studiedmore in the future.

关键词： Computer science  

摘要： According to the World Health Organization (WHO, 2017), 5% of the world’s population have hearing loss. Most people with hearing disabilities communicate via sign language, which hearing people find extremely difficult to understand. To facilitate communication of deaf and hard of hearing people, developing an efficient communication system is a necessity. There are many challenges associated with the Sign Language Recognition (SLR) task, namely, lighting conditions, complex background, signee body postures, camera position, occlusion, complexity and large variations in hand posture, no word alignment, coarticulation, etc. Sign Language Recognition has been an active domain of research since the early 90s. However, due to computational resources and sensing technology constraints, limited advancement has been achieved over the years. Existing sign language translation systems mostly can translate a single sign at a time, which makes them less effective in daily-life interaction. This work develops a novel sign language recognition framework using deep neural networks, which directly maps videos of sign language sentences to sequences of gloss labels by emphasizing critical characteristics of the signs and injecting domain-specific expert knowledge into the system. The proposed model also allows for combining data from variant sources and hence combating limited data resources in the SLR field.

关键词： Consensus protocol   Computer architecture   Peer-to-peer computing   Data models   Smart contracts   Licenses   Computer science   Blockchain   PoW   PoS   DPoS   PoA   consensus protocol  

摘要： As Blockchain innovation picks up popularity in many areas, it is frequently hailed as a sound innovation. Because of the decentralization and encryption, many imagine that data put away in a Blockchain is and will consistently be protected. Among various abstraction layers of Blockchain architecture, the consensus layer is the core component behind the performance and security measures of the Blockchain network. Consensus mechanisms are a critical component of a Blockchain system's long-term stability. Consensus forms the core of blockchain technology. Therefore, a range of consensus protocols has been introduced to maximize Blockchain systems' efficiency and meet application domains' individual needs. This research paper describes the layered architecture of Blockchain. A comprehensive review of mainstream consensus protocols mainly Proof of Work (PoW), Proof of Stake (PoS), Delegated Proof of Stake (DPoS), Proof of Activity (PoA) is presented in the paper. These mainstream consensus protocols have been explained and detailed performance analysis of these consensus protocols has been done. We have proposed a performance matrix of these consensus protocols based on different parameters like Degree of decentralization, Latency, Fault Tolerance Rate, Scalability, etc. Consensus protocols being the core of a strong fault-tolerant secured blockchain system, the proposed work intends to help inappropriate protocol selection and further research on strengthening trust and ownership in the technology. Depending upon different parameters like decentralization which is low in POA compared to other protocols, whereas POW is non-scalable, so depending on the priority of a particular performance parameter, the paper will help in the selection of a specific protocol.

摘要： Computer science education is being recognized globally as necessary to better prepare students in all grade levels, K-12, for future success. As a result of this focus on computer science education in the United States and around the world, there is an increased demand for highly qualified teachers with content and pedagogical knowledge to successfully support student learning. As a result, there is a call to include and improve the computer science training offered to pre-service teachers in their educator preparation programs from methods courses to practicum and student teaching experiences. Thus, it is important to understand how pre-service teachers view content, classroom practices, and teaching and learning methodologies and theories to inform teacher educators about best practices for integrating computer science. This multi-case study investigated pre-service teachers’ perceived abilities and intent to integrate the Virginia Computer Science Standards of Learning into future content area instruction, as well as any shifts that occurred in these pre-service teachers’ perceptions as a result of their student teaching experience. Five elementary pre-service teachers enrolled in a teacher preparation program at a large, public research university in the Mid-Atlantic region of the United States comprised the cases in this research study. Data were collected during the participants’ student teaching experience and final semester in their respective programs and was comprised of the following: pre-, mid-, and post-questionnaires, meeting transcriptions (2), semi-structured individual phone interview transcriptions (2), and written/posted exchanges on an online discussion board. Data representing each case were analyzed using a qualitative general inductive approach as outlined by Thomas. A within-case analysis was performed to develop main categories and identify central themes for each case, and a cross-case analysis was then conducted using the NVivo Qualitativ

关键词： Routing   Topology   Roads   Protocols   Licenses   Computer science   Buildings   Independent spanning trees   generalized recursive circulant graphs   interconnection networks  

摘要： The generalized recursive circulant networking can be widely used in the design and implementation of interconnection networks. It consists of a series of processors, each is connected through bidirectional, point-to-point communication channels to different neighbors. In this work, we apply the shortest path routing concept to build independent spanning trees on the generalized recursive circulant graphs. The proposed strategy loosen the restricted conditions in previous research and extended the result to a more general vertex setting by design the specific algorithm to deal with the constraint issue.

关键词： Microwave integrated circuits   Mutual information   Entropy   Feature extraction   Computer science   Time complexity   Licenses   Data mining   association detection   information entropy   maximum information coefficient   upper confidence bound  

摘要： The maximum information coefficient (MIC) is a novel and widely-using measure of association detection in large datasets. The most outstanding feature of MIC is that it has both generality and equability. However, MIC can only deal with two variables and cannot precisely estimate coupling associations of multiple variables. In this paper, we propose an extension of MIC to deal with multi-variable datasets, called the multi-variable maximum information coefficient (MMIC). Some inherited and novel properties of MMIC are proved, including generality, equability, monotonicity, and subadditivity. We design an algorithm based on greedy stepwise strategy and upper confidence bound (UCB) for an approximate calculation of MMIC. The tests of MMIC on generated datasets and examples on real datasets are carried out to detect known and novel associations.

关键词： Algorithmic game theory   Congestion games   Equilibrium computation   Game theory   Multi-sided markets  

摘要： This dissertation considers a number of problems in pure and applied game theory. The first chapter considers the problem of how the introduction of fines and monitoring affects welfare in a routing game. I characterize equilibria of the game and discuss network topologies in which the introduction of fines can harm those agents which are not subject to them. The second, and primary, chapter considers the computational aspects of tenable strategy sets. I characterize these set-valued solution concepts using the more familiar framework of perturbed strategies, introduce strong alternatives to the problems of verifying whether a strategy block satisfies the conditions of tenability, and provide some hardness results regarding the verification of fine tenability. Additionally, I show an inclusion relation between the concept of coarse tenability and the notion of stability introduced by Kohlberg and Mertens (1986). Finally, I show how the methods developed for tenability provide an alternative characterization for proper equilibria in bimatrix games. This characterization gives a bound on the perturbations required in the definition of proper equilibria, though such bounds cannot be computed efficiently in general. The third, and final, chapter develops a model of contracting for content creation in an oligopolistic environment of attention intermediaries. I characterize symmetric equilibria in single-homing (exclusive) and multi-homing regimes. The focus is on the trade-off between reductions in incentives offered by intermediaries and the benefits of access to additional content for consumers. I show that when the extent of multi-homing is exogenous in the absence of exclusivity clauses, consumer surplus is always higher with multi-homing than under exclusivity, despite weaker incentives offered by platforms to content creators.

关键词： Computer science  

摘要： Face recognition is a widely adopted technology with numerous applications, such as mobile phone unlock, mobile payment, surveillance, social media and law enforcement. There has been tremendous progress in enhancing the accuracy of face recognition systems over the past few decades, much of which can be attributed to deep learning. Despite this progress, several fundamental problems in face recognition still remain unsolved. These problems include finding a salient representation, estimating intrinsic dimensionality, representation capacity, and demographic bias. With growing applications of face recognition, the need for an accurate, robust, compact and fair representation is evident. In this thesis, we first develop algorithms to obtain practical estimates of intrinsic dimensionality of face representations, and propose a new dimensionality reduction method to project feature vectors from ambient space to intrinsic space. Based on the study in intrinsic dimensionality, we then estimate capacity of face representation, casting the face capacity estimation problem under the information theoretic framework of capacity of a Gaussian noise channel. Numerical experiments on unconstrained faces (IJB-C) provide a capacity upper bound of 27,000 for FaceNet and 84,000 for SphereFace representation at 1% FAR. In the second part of the thesis, we address the demographic bias problem in face recognition systems where errors are lower on certain cohorts belonging to specific demographic groups. We propose two de-biasing frameworks that extract feature representations to improve fairness in face recognition. Experiments on benchmark face datasets (RFW, LFW, IJB-A, and IJB-C) show that our approaches are able to mitigate face recognition bias on various demographic groups (biasness drops from 6.83 to 5.07) as well as maintain the competitive performance (i.e., 99.75% on LFW, and 93.70% TAR @ 0.1% FAR on IJB-C). Lastly, we explore the global distribution of deep face representati