Visualizations of Digital Interaction in Daily Life

We inquire into how visual signage may make aspects of ubiquitous computing technologies visible and how digital tools and platforms impact that visual design and semiosis. We explore how visual interfaces have been designed and mediated within a design-research project that looked at technologies for mediating between digital media and the physical environment. Referring to visual and media theory, and to social semiotics, we problematize the role of interfaces and interaction with respect to advertising, services, and signage in urban settings. We link our interpretation to critical reflection on designed symbols that express potentials and implications of an emerging technology. This is elaborated as pointing towards a kind of research-by-design practice that we call “discursive design.”     

虚拟世界中操纵技术的研究进展I:现有技术及分类

虚拟环境(VE)的应用要求很好的优化交互技术,从而最大地发挥操作者的作用并提供高效、愉悦的虚拟界面。该文讨论了现有技术,并根据现有技术的设计思想对其进行了分类,为进一步评价现有技术提供基础。     

虚拟世界中的操纵技术研究进展II:对现有操纵技术的实验评价

随着VE技术日益被接受,在VE交互作用中如何最大地发挥操作者的作用将受到更多的关注。文章综述了沉浸式交互技术中最重要的问题之一:用于沉浸式对象选择和定位的交互技术,得到了一些通用性的VE界面的设计概念。     

On Interaction between Interconnection Network Design and Latency Hiding Techniques in Multiprocessors

Latency hiding techniques are increasingly used to minimize the effect of a long memory latency in multiprocessors. Their use requires additional network bandwidth. The network organization and its design parameters alone can significantly affect performance. With latency hiding, system performance depends on how well the interconnection network can support the use of such techniques and their interaction with network organization. This paper investigates these issues for prefetching and weak consistency in a 128-processor shared-memory system with either a 2-D torus, a multistage, or a single-stage network. The performance impact of network organization and the link bandwidth, with and without the use of latency hiding techniques is shown. The effect of caching and of limiting the number of outstanding memory requests is shown. Multistage is the most robust network and has the best performance under all conditions. Single-stage network is very close in performance when sufficient channel bandwidth is available. Torus network comes in last when channel bandwidth is high, but can exceed single stage performance when it is low. The relative performance of the three networks with prefetching remains similar, with torus gaining the most. Benchmark execution time can decrease by as much as 25% with prefetching. Further gains depend on reducing the effect of write traffic. Finally, the existence of an optimal number of outstanding requests is shown but the value is program-dependent.     

Building and Selecting Mobile Agents for Network Management

This paper presents a framework for reusable mobile agents for network management in the sense that they are independent of either particular networks or applications. The framework enables a mobile agent to be composed from two layered components, which are mobile agents. The former is a carrier of the latter over particular networks independent of any management tasks and the latter defines management tasks performed at each host independently of any networks. The framework also offers a mechanism for matchmaking the two components. Since the mechanism is formulated on a process algebra approach, it can accurately select the appropriate itinerary component to perform management tasks at hosts that the tasks want to visit over networks. The framework provides a methodology for easily developing and operating mobile agents for traveling among multiple sub-networks to perform their management tasks at all of the nodes that they visit. This paper also describes the framework, its prototype implementation, and a practical application.

Reusable Visualizations and Animations for Surgery Planning

For surgical planning, the exploration of 3D visualizations and 2D slice views is essential. However, the generation of visualizations which support the specific treatment decisions is very tedious. Therefore, the reuse of once designed visualizations for similar cases can strongly accelerate the process of surgical planning. We present a new technique that enables the easy reuse of both medical visualization types: 3D scenes and 2D slice views. We introduce the keystates as a concept to describe the state of a visualization in a general manner. They can be easily applied to new datasets to create similar visualizations. Keystates can be shared between surgeons of one specialization to reproduce and document the planning process for collaborative work. Furthermore, animations can support the surgeon on individual exploration and are also useful in collaborative environments, where complex issues must be presented in a short time. Therefore, we provide a framework, where animations can be visually designed by surgeons during their exploration process without any programming or authoring skills. We discuss several transitions between different visualizations and present an application from clinical routine.     

网络流媒体系统中多发送者选择算法

于SVC视频服务的融合网络流媒体系统中,存在传输网络异构、终端上行带宽受限和参与者持有相同SVC视频编码源的不同比例。基于这样的流媒体系统往往需要多个发送者才能服务一个接收者。上行带宽、持有编码流的比例等是选择候选发送者的主要参数,多参数优化下的多发送者选择算法是一个NP问题。对于一群候选发送者,文章提出一个以尽可能少的发送者数去满足接收者最大需求的选择算法-MSSA,性能分析显示本文算法比同类算法有更好的网络系统稳定性。     

Spatial Input for Temporal Navigation in Scientific Visualizations

Scientific-visualization tools can make time-varying simulations easier to understand. The growing efficiency of today's high-performance computers enables simulation of physical phenomena with a high temporal resolution. Consequently, visualization systems require efficient navigation in the temporal dimension. This 3D user interface employs direct-manipulation metaphors for temporal navigation in scientific visualizations. By interacting with objects using their 3D trajectory, users can navigate in time by specifying spatial inputs. This article is part of a special issue on 3D user interfaces.     

Internal and External Visual Cue Preferences for Visualizations in Presentations

Presenters, such as analysts briefing to an executive committee, often use visualizations to convey information. In these cases, providing clear visual guidance is important to communicate key concepts without confusion. This paper explores visual cues that guide attention to a particular area of a visualization. We developed a visual cue taxonomy distinguishing internal from external cues, designed a web tool based on the taxonomy, and conducted a user study with 24 participants to understand user preferences in choosing visual cues. Participants perceived internal cues (e.g., transparency, brightness, and magnification) as the most useful visual cues and often combined them with other internal or external cues to emphasize areas of focus for their audience. Interviews also revealed that the choice of visual cues depends on not only the chart type, but also the presentation setting, the audience, and the function cues are serving. Considering the complexity of choosing visual cues, we provide design implications for improving the organization, consistency, and integration of visual cues within existing workflows.     

Illustrative Motion Smoothing for Attention Guidance in Dynamic Visualizations

3D animations are an effective method to learn about complex dynamic phenomena, such as mesoscale biological processes. The animators' goals are to convey a sense of the scene's overall complexity while, at the same time, visually guiding the user through a story of subsequent events embedded in the chaotic environment. Animators use a variety of visual emphasis techniques to guide the observers' attention through the story, such as highlighting, halos – or by manipulating motion parameters of the scene. In this paper, we investigate the effect of smoothing the motion of contextual scene elements to attract attention to focus elements of the story exhibiting high-frequency motion. We conducted a crowdsourced study with 108 participants observing short animations with two illustrative motion smoothing strategies: geometric smoothing through noise reduction of contextual motion trajectories and visual smoothing through motion blur of context items. We investigated the observers' ability to follow the story as well as the effect of the techniques on speed perception in a molecular scene. Our results show that moderate motion blur significantly improves users' ability to follow the story. Geometric motion smoothing is less effective but increases the visual appeal of the animation. However, both techniques also slow down the perceived speed of the animation. We discuss the implications of these results and derive design guidelines for animators of complex dynamic visualizations.     

Optimization Techniques for Reactive Network Monitoring

We develop a framework for minimizing the communication overhead of monitoring global system parameters in IP networks and sensor networks. A global system predicate is defined as a conjunction of the local properties of different network elements. A typical example is to identify the time windows when the outbound traffic from each network element exceeds a predefined threshold. Our main idea is to optimize the scheduling of local event reporting across network elements for a given network traffic load and local event frequencies. The system architecture consists of N distributed network elements coordinated by a central monitoring station. Each network element monitors a set of local properties and the central station is responsible for identifying the status of global parameters registered in the system. We design an optimal algorithm, the Partition and Rank (PAR) scheme, when the local events are independent; whereas, when they are dependent, we show that the problem is NP-complete and develop two efficient heuristics: the PAR for dependent events (PAR-D) and Adaptive (Ada) algorithms, which adapt well to changing network conditions, and outperform the current state of the art techniques in terms of communication cost.     

实现校园网的技术要点

本文介绍一个校园网的总体方案，并讨论分析实现校园网的一些关键技术。     

桌面虚拟现实环境下的双手交互技术

面向桌面虚拟环境,在分析通用交互设备特点的基础上,提出了具有广泛适用性的双手交互的设备组合;根据虚拟现实通用交互任务的需求,结合设备特点,提出了为左、右手设备分配不同的子任务的策略;组合不同的单手交互技术,提出了包括基于辅助平面的双手交互等3个适用于典型桌面设备组合的双手交互技术;开发了双手交互技术工具箱,并进行了应用验证.     

Dual-Finger 3D Interaction Techniques for mobile devices

Three-dimensional capabilities on mobile devices are increasing, and the interactivity is becoming a key feature of these tools. It is expected that users will actively engage with the 3D content, instead of being passive consumers. Because touch-screens provide a direct means of interaction with 3D content by directly touching and manipulating 3D graphical elements, touch-based interaction is a natural and appealing style of input for 3D applications. However, developing 3D interaction techniques for handheld devices using touch-screens is not a straightforward task. One issue is that when interacting with 3D objects, users occlude the object with their fingers. Furthermore, because the user’s finger covers a large area of the screen, the smallest size of the object users can touch is limited. In this paper, we first inspect existing 3D interaction techniques based on their performance with handheld devices. Then, we present a set of precise Dual-Finger 3D Interaction Techniques for a small display. Finally, we present the results of an experimental study, where we evaluate the usability, performance, and error rate of the proposed and existing 3D interaction techniques.     

网络攻击与防范技术

网络攻击是指网络用户未经授权地访问或者使用网络资源,网络攻击方法众多,其攻击目标也不尽相同.简单介绍了网络攻击的目标、分类、攻击的基本过程和常见攻击与防范技术.     

个人用户对网络病毒的防范技巧

2001年作为新世纪的第一年,注定是不平凡的一年:当个人计算机迎来它的20岁生日的同时,恶毒的“欢乐时光”病毒和“红色代码”病毒、“尼姆达”等通过网络袭击了全球的计算机系统,给人类带来巨大损失。我们注意到这段时期以来各种具有新特性和强大破坏力的病毒层出不穷,尽管我们一直在想办法,但病毒是层出不穷,时时威胁着信息数据的安全。     

Neural Network Techniques for Proactive Password Checking

This paper deals with the access control problem. We assume that valuable resources need to be protected against unauthorized users and that, to this aim, a password-based access control scheme is employed. Such an abstract scenario captures many applicative settings. The issue we focus our attention on is the following: password-based schemes provide a certain level of security as long as users choose good passwords, i.e., passwords that are hard to guess in a reasonable amount of time. In order to force the users to make good choices, a proactive password checker can be implemented as a submodule of the access control scheme. Such a checker, any time the user chooses/changes his own password, decides on the fly whether to accept or refuse the new password, depending on its guessability. Hence, the question is: how can we get an effective and efficient proactive password checker? By means of neural networks and statistical techniques, we answer the above question, developing suitable proactive password checkers. Through a series of experiments, we show that these checkers have very good performance: error rates are comparable to those of the best existing checkers, implemented on different principles and by using other methodologies, and the memory requirements are better in several cases. It is the first time that neural network technology has been fully and successfully applied to designing proactive password checkers     

Building on Realism and Magic for Designing 3D Interaction Techniques

Imagination-based interaction can complement reality-based interaction in the design of 3D UIs. This hybrid approach could lead to interface design guidelines that promote higher-level consistency, and thus usability, for a large range of diverse interfaces.     

Evaluating Free Rides and Observational Advantages in Set Visualizations

Free rides and observational advantages occur in visualizations when they reveal facts that must be inferred from an alternative representation. Understanding whether these concepts correspond to cognitive advantages is important: do they facilitate information extraction, saving the ‘deductive cost’ of making inferences? This paper presents the first evaluations of free rides and observational advantages in visualizations of sets compared to text. We found that, for Euler and linear diagrams, free rides and observational advantages yielded significant improvements in task performance. For Venn diagrams, whilst their observational advantages yielded significant performance benefits over text, this was not universally true for free rides. The consequences are two-fold: more research is needed to establish when free rides are beneficial, and the results suggest that observational advantages better explain the cognitive advantages of diagrams over text. A take-away message is that visualizations with observational advantages are likely to be cognitively advantageous over competing representations.