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关键词： Encryption   Cryptography   Heuristic algorithms   Privacy   Mathematical models   Computer science   Approximation algorithms   Chosen-plaintext attack   cryptanalysis   image encryption   chaotic cryptography   image privacy  

摘要： Security is a key problem for the transmission, interchange, and storage process of multimedia systems and applications. In 2018, Li et al. proposed in-depth security analysis on an image encryption algorithm based on a first-order time-delay system (IEATD) and gave a specific chosen-plaintext attack on it. Moreover, an enhanced version called as IEACD was designed to fix the reported security defects. This article analyzes the essential structures of the two algorithms and evaluates their real security performances: 1) no efficient nonlinear operations are adopted to assure the sensibility of keystream;2) the equivalent secret key of IEATD can be efficiently recovered from one known plain-image and the corresponding cipher-image;and 3) IEACD can still be efficiently cracked with a chosen-plaintext attack. Both rigorous theoretical analyses and detailed experimental results are provided to demonstrate effectiveness of the advanced cryptanalytic methods.

关键词： Computer Science   Wireless Communication   Wireless Sensor Networks   Translational Research   Smart Cities   Instruments   Social Sciences  

摘要： Chicago's Array of Things (AoT) project is aptly described as a technology experiment or a "smart city" prototype. The concept of such an extensible "instrument" arose within a larger translational research vision applying computer science and engineering research for the multidimensional benefit of people and communities in cities. The AoT project hypothesized that wireless intelligent sensor networks could enable both quantitative social science and urban monitoring while also stimulating youth interest in science and technology. Successful deployment of such sensor networks could provide open data from urban measurements not only in support of diverse research questions-in environmental dynamics, urban architecture, engineering, and social sciences-but also informing community groups and city planners. The AoT project and its successor SAGE project are a computer science and engineering experiment, but its success is inextricably tied to community engagement and experiential education. Simply put, community acceptance is a prerequisite to installing and testing the instrument.

关键词： 教—学—评”一致性   初中英语   听说教学   教学设计   评价方式  

摘要： 介绍"教—学—评"一致性理念的提出及其应用现状。阐述"教—学—评"一致性理念的内涵与意义,即教师的教、学生的学、课堂评价三者有机结合。以人教版新目标初中《英语》八年级(上)Unit 6I’m going to study computer science Section A 1a—2c为例,探索如何基于"教—学—评"一致性理念设计听说教学。提出合理制订学习目标,保障"教—学—评"一致性;优化设计评价方式,助力"教—学—评"一致性;听说有效组织教学活动,促进"教—学—评"一致性等策略。从学习目标是否精准可评、评价任务是否契合目标、教学活动是否匹配评价三个方面进行反思与展望。

关键词： Real-time systems   Malware   Security   Electronic mail   Computer science   Data mining   Semantics   Advanced persistent threat   hosted-based security   real-time detection  

摘要： Advanced Persistent Threat (APT) attacks have caused serious security threats and financial losses worldwide. Various real-time detection mechanisms that combine context information and provenance graphs have been proposed to defend against APT attacks. However, existing real-time APT detection mechanisms suffer from accuracy and efficiency issues due to inaccurate detection models and the growing size of provenance graphs. To address the accuracy issue, we propose a novel and accurate APT detection model that removes unnecessary phases and focuses on the remaining ones with improved definitions. To address the efficiency issue, we propose a state-based framework in which events are consumed as streams and each entity is represented in an FSA-like structure without storing historic data. Additionally, we reconstruct attack scenarios by storing just one in a thousand events in a database. Finally, we implement our design, called Conan, on Windows and conduct comprehensive experiments under real-world scenarios to show that Conan can accurately and efficiently detect all attacks within our evaluation. The memory usage and CPU efficiency of Conan remain constant over time (1-10 MB of memory and hundreds of times faster than data generation), making Conan a practical design for detecting both known and unknown APT attacks in real-world scenarios.

关键词： Diagnostics   prognostics of an assembly-line worker   Worker’ comfortable work duration   Machine learning  

摘要： Worker’ work-rotation between the workstations of an assembly line is a common task to an assembly line manager, to manage the workload between the assembly line workers. Usually, worker work rotation makes an interruption to a continuous production system. It is a desire of an assembly line manager to avoid the worker’s work-rotation, at least between the work breaks. This work aims to protect the manager’s interest by predicting the comfortable work-duration time of an assembly line worker for a given work, based on the working condition and the instantaneous physical & mental status of the worker. The comfortable work-duration time can be used during the worker’s work assignment to reduce interruptions. Factors, which influence the longevity of workers’ comfortable work duration time are identified. IIoT based sensors are proposed here to monitor the relevant factors for diagnostics. Machine Learning techniques are used as a part of prognostics to predict the comfortable work-duration time of a worker, based on his/her physical & mental status. Implementation methodology is explained along with a simulated experiment.

关键词： 高中   信息技术教学   计算机科学  

摘要： 随着时代的飞速发展,信息技术成为时代进步绕不开的话题,在进行高中信息技术教学中渗透计算机科学史的教育时,需要培养学生的学科意识,树立学科精神,提高学科素养﹐为计算机信息技术的长远发展奠定基础。文章针对目前高中阶段的信息技术教学现状进行分析、探究,提出了相关策略,希望以促进计算机科学在高中信息技术教学中的渗透,提高教学效率,促进我国信息技术的长远发展。

关键词： Computer product carbon footprint   computer life cycle assessment   computer science   computer human computer interaction   sustainable information technology  

摘要： End user computing generates 1% of global greenhouse gas emissions therefore contributing to environmental pollution, global warming and ultimately climate change. Research indicates the carbon footprint is predominantly produced by production and use-phase electricity consumption. As such, new international legislation exists to ensure businesses include sustainability criteria when assessing and purchasing computers. Such criteria must include valid science based evidence that the selected devices, contribute to greenhouse gas abatement and net-zero emissions strategies based upon exhibiting a low life cycle carbon footprint. As such, it is reasonable to suggest that sufficient carbon footprint information must be publicly available to enable the selection process to be meaningful. The rationale being that if information is limited or misleading, then accurate identification and comparison between computers cannot be assured. Consequently, the research objective is to quantify availability of end user computing carbon footprint information, examine data uniformity and validity and propose a solution to overcome identified issues. To enable this, asset profiling of 71,990 end user computing devices located at six organisations is undertaken to generate an unbiased data pool representing popular devices used by organisations subject to the new procurement rules. Carbon footprint reports are sought for each unique model identified to examine both scope 2 use-phase emissions and scope 3 supply chain manufacturing emissions data. The findings substantiate that 22% of the 707 unique end user computer models identified have associated published information. The predominant limitation being that only six of the forty-two computer brands identified participate in product carbon footprint reporting. Additionally, methods used to form and present the carbon footprint data are incongruent for both emissions sources. Scope 3 is affected by a feasible range of emissions methodo

关键词： 项目教学法   中学   计算机基础教学  

摘要： 为顺应教学改革工作的要求,中学计算机教师要积极对基于项目的学习模式进行分析和应用,确保学生可以在基于项目的计算机基础学习中更好地掌握计算机知识,发挥学生在计算机基础课程学习中的主观能动性。基于项目的学习在中学计算机基础教学中的应用,能够在一定程度上提高教学工作水平,以及较好地培养学生的学习能力,有助于学生未来的发展。

关键词： Training   Linear programming   Silicon   Manifolds   Optimization   Noise measurement   Computer science   Adaptive graph   graph construction   high-dimensional data   semisupervised classification (SSC)   subspace learning  

摘要： Graph-based methods have achieved impressive performance on semisupervised classification (SSC). Traditional graph-based methods have two main drawbacks. First, the graph is predefined before training a classifier, which does not leverage the interactions between the classifier training and similarity matrix learning. Second, when handling high-dimensional data with noisy or redundant features, the graph constructed in the original input space is actually unsuitable and may lead to poor performance. In this article, we propose an SSC method with novel graph construction (SSC-NGC), in which the similarity matrix is optimized in both label space and an additional subspace to get a better and more robust result than in original data space. Furthermore, to obtain a high-quality subspace, we learn the projection matrix of the additional subspace by preserving the local and global structure of the data. Finally, we intergrade the classifier training, the graph construction, and the subspace learning into a unified framework. With this framework, the classifier parameters, similarity matrix, and projection matrix of subspace are adaptively learned in an iterative scheme to obtain an optimal joint result. We conduct extensive comparative experiments against state-of-the-art methods over multiple real-world data sets. Experimental results demonstrate the superiority of the proposed method over other state-of-the-art algorithms.

关键词： Abstracts   Computer Science   Conference   Noun Phrase Complexity  

摘要： Noun phrase (NP) complexity research has shown the effects of both discipline and writing competence on NP complexity in academic writing and has focused more on applied linguistics. Yet few studies examined NPs in the academic writing of computer science (CS), especially in the CS conference abstract writing, in depth. This study fills this gap by investigating the disciplinary preference of NPs through the corpus analysis of 267 published abstracts from a leading CS conference. The authors found that multiple pre-modifiers were the most frequently used device by CS researchers, and attributive adjectives, nouns, and prepositional phrases were fundamental in abstract composition in both CS and applied linguistics. The difference largely lies in the use of devices in later-acquired stages. CS researchers favor more multiple pre-modifiers while their peers in applied linguistics tend to prefer multiple prepositional phrases as post-modifiers. The findings shed light on classroom instruction and future research on NP complexity.