Guided Image Filtering for Interactive High‐quality Global Illumination

Interactive computation of global illumination is a major challenge in current computer graphics research. Global illumination heavily affects the visual quality of generated images. It is therefore a key attribute for the perception of photo‐realistic images. Path tracing is able to simulate the physical behaviour of light using Monte Carlo techniques. However, the computational burden of this technique prohibits interactive rendering times on standard commodity hardware in high‐quality. Trying to solve the Monte Carlo integration with fewer samples results in characteristic noisy images. Global illumination filtering methods take advantage of the fact that the integral for neighbouring pixels may be very similar. Averaging samples of similar characteristics in screen‐space may approximate the correct integral, but may result in visible outliers. In this paper, we present a novel path tracing pipeline based on an edge‐aware filtering method for the indirect illumination which produces visually more pleasing results without noticeable outliers. The key idea is not to filter the noisy path traced images but to use it as a guidance to filter a second image composed from characteristic scene attributes that do not contain noise by default. We show that our approach better approximates the Monte Carlo integral compared to previous methods. Since the computation is carried out completely in screen‐space it is therefore applicable to fully dynamic scenes, arbitrary lighting and allows for high‐quality path tracing at interactive frame rates on commodity hardware.     

Direct Ray Tracing of Phong Tessellation

There are two major ways of calculating ray and parametric surface intersections in rendering. The first is through the use of tessellated triangles, and the second is to use parametric surfaces together with numerical methods such as Newton's method. Both methods are computationally expensive and complicated to implement. In this paper, we focus on Phong Tessellation and introduce a simple direct ray tracing method for Phong Tessellation. Our method enables rendering smooth surfaces in a computationally inexpensive yet robust way.     

Parents,pre‐schoolers and learning with technology at home: some implications for policy

Schemes that seek to ensure that children have access to technology at home have, so far, been aimed at children over the age of 8. However, there is likely to be an increasing policy interest in extending similar schemes to pre‐school children given widespread commitment to the value of early intervention in children's education and family life. We draw on three research studies conducted by the authors to discuss the range of technologies that children encounter at home, the different forms their learning takes and family support for learning. We use these findings to provide starting points for considering the implementation of similar schemes for pre‐school children and their parents in the future, identifying several questions to consider when developing policy on home access to technology for pre‐schoolers: which technologies are most appropriate? Will access to technology at home lead to increased use? What roles do parents play in supporting learning? Which forms of learning are most likely to be promoted?     

Multi‐agent system for knowledge‐based event recognition and composition

This work presents a multi‐agent system for knowledge‐based high‐level event composition, which interprets activities, behaviour and situations semantically in a scenario with multi‐sensory monitoring. A perception agent (plurisensory agent and visual agent)‐based structure is presented. The agents process the sensor information and identify (agent decision system) significant changes in the monitored signals, which they send as simple events to the composition agent that searches for and identifies pre‐defined patterns as higher‐level semantic composed events. The structure has a methodology and a set of tools that facilitate its development and application to different fields without having to start from scratch. This creates an environment to develop knowledge‐based systems generally for event composition. The application task of our work is surveillance, and event composition/inference examples are shown which characterize an alarming situation in the scene and resolve identification and tracking problems of people in the scenario being monitored.     

Applying intelligent agents and semantic web services in eGovernment environments

The increasing volume of eGovernment‐related services is demanding new approaches for service integration and interoperability in this domain. Semantic web (SW) technologies and applications can leverage the potential of eGovernment service integration and discovery, thus tackling the problems of semantic heterogeneity characterizing eGovernment information sources and the different levels of interoperability. eGovernment services will therefore be semantically described in the foreseeable future. In an environment with semantically annotated services, software agents are essential as the entities responsible for exploiting the semantic content in order to automate some tasks, and so enhance the user's experience. In this paper, we present a framework that provides a seamless integration of semantic web services and intelligent agents technologies by making use of ontologies to facilitate their interoperation. The proposed framework can assist in the development of powerful and flexible distributed systems in complex, dynamic, heterogeneous, unpredictable and open environments. Our approach is backed up by a proof‐of‐concept implementation, where the breakthrough of integrating disparate eGovernment services has been tested.     

The effect of Twitter on college student engagement and grades

Despite the widespread use of social media by students and its increased use by instructors, very little empirical evidence is available concerning the impact of social media use on student learning and engagement. This paper describes our semester‐long experimental study to determine if using Twitter – the microblogging and social networking platform most amenable to ongoing, public dialogue – for educationally relevant purposes can impact college student engagement and grades. A total of 125 students taking a first year seminar course for pre‐health professional majors participated in this study (70 in the experimental group and 55 in the control group). With the experimental group, Twitter was used for various types of academic and co‐curricular discussions. Engagement was quantified by using a 19‐item scale based on the National Survey of Student Engagement. To assess differences in engagement and grades, we used mixed effects analysis of variance (ANOVA) models, with class sections nested within treatment groups. We also conducted content analyses of samples of Twitter exchanges. The ANOVA results showed that the experimental group had a significantly greater increase in engagement than the control group, as well as higher semester grade point averages. Analyses of Twitter communications showed that students and faculty were both highly engaged in the learning process in ways that transcended traditional classroom activities. This study provides experimental evidence that Twitter can be used as an educational tool to help engage students and to mobilize faculty into a more active and participatory role.     

Practices with technology: learning at the boundary between study and work

A study of part‐time student experience of university courses delivered using a range of technologies found that information and communication technology enabled students to move between study and work experience to the benefit of their learning in both contexts. Technology‐based study activities enabled students to participate in learning both as a student and as a member of a practice or work context. Given the increasingly pressured lives of all students in higher education and their aspirations for employment after graduation, this suggests that we would benefit from taking their relationship to work and professional practice into account more directly, in deciding how to integrate technology into their study experience. Teacher conceptions of technology as a tool primarily for information delivery and discussion need to expand to recognize that it can be used to construct learning experiences situated in roles, skills and interactive environments that enhance students' ability to make transitions across the boundaries between contexts of study and work.     

C2网络组织谣言传播的建模与仿真*

针对指挥控制（C2）网络组织谣言传播具有动态性、适应性、非线性,采用多agent的建模方法,对谣言传播过程与网络组织的互动行为模式进行了描述和分析,得到了节点间影响水平、谣言源的特征、指挥跨度和最终接受谣言比例之间的关系。主要结论有：（1）在谣言传播的过程中,下级对上级的影响力对最终接受谣言规模更加敏感;（2）谣言源特征对最终接受谣言规模有影响,且谣言源的身份越高,对谣言传播效果的影响越大;（3）指挥跨度越大,越有利于谣言的传播。     

片上多核Cache资源管理机制研究

随着片上多核成为处理器发展的主流和片上Cache资源的持续增长,Cache资源的管理已成为片上多核的关键问题。介绍了片上多核Cache资源管理的研究进展,依据研究内容将Cache资源的管理分为Cache划分和Cache共享两类。对Cache划分,探讨了其主要组成部分和一般形式,分析和比较了典型的片上多核Cache划分机制。对Cache共享,给出了其主要研究内容,并介绍和比较了几种主流的片上多核Cache共享机制。通过分析,认为软硬件协同管理的页划分应是未来片上多核Cache划分机制的研究重点;而片上多核Cache共享机制的研究则应从目标应用的Cache行为特征着手。     

多输入非线性串级系统的非过参数化自适应控制

证明了一大类含有未知参数的多输入非线性串级系统在适当的假设条件下是可全局适应稳定的,自适应控制律的设计是基于ｂａｃｋｓｔｅｐｐｉｎｇ递推设计方法,得到的参数自适应律的阶次等于未知参数的个数,因此该设计是非过参数化的。