Multi-camera systems for rehabilitation therapies: a study of the precision of Microsoft Kinect sensors

This paper seeks to determine how the overlap of several infrared beams affects the tracked position of the user, depending on the angle of incidence of light, distance to the target, distance between sensors, and the number of capture devices used. We also try to show that under ideal conditions using several Kinect sensors increases the precision of the data collected. The results obtained can be used in the design of telerehabilitation environments in which several RGB-D cameras are needed to improve precision or increase the tracking range. A numerical analysis of the results is included and comparisons are made with the results of other studies. Finally, we describe a system that implements intelligent methods for the rehabilitation of patients based on the results of the tests carried out.     

A flick in the right direction: a case study of gestural input

This paper describes the design and evaluation of a gesture-based scheme for issuing the back and forward commands in web browsers. In designing our gesture recogniser we conducted several experiments to determine metrics associated with the magnitude, timing and stereotypical errors of 'natural' linear flick gestures using stylus and mouse input devices. These low-level metrics are important to software designers who must implement algorithms that discriminate between gestures and other actions such as mouse clicks and drags. As well as empirically characterising gestures, the metrics provide various insights into stereotypical behaviour with gestures, including the facts that angular errors are larger in the left and right directions with the pen, that vertical gestures are 'awkward' with the mouse, and that downwards gestures are slower than other directions. An evaluation of gestures for web browsing shortcuts shows that they enhance navigation efficiency, and that participants were extremely enthusiastic about them.     

基于Leap Motion和Unity3D的虚拟沙画手势识别及交互

虚拟仿真技术的快速发展及体感设备的不断更新为沙画动画这一全新的艺术创作形式带来新的灵感。针对沙画现场作画工序复杂的问题,结合Leap Motion设备和Unity3D开发环境完成手势识别并驱动虚拟手实现虚拟沙画效果。首先,依据Leap Motion捕捉到的手势坐标及方向信息提取手部关键点;然后提出角域划分的方法并引入新的特征向量,将其与提取信息串联作为手势分类依据;最后,根据自行定义的沙画手势语义驱动虚拟手完成虚拟沙画创作。实验证明,利用Leap Motion完成近距离手势识别效果较其他方法结果更加精准,实时性较高,手势跟踪稳定,虚拟沙画绘画过程沉浸感强。     

Interactive lounge: an interdisciplinary approach to the design of a gestural interaction device

Among the many new opportunities that digital technologies are enabling are an increased capacity for viewers to interact not only with the program content, but with an increasingly wide array of other digital applications. Within this context this project has developed a new interaction device (incorporating gestural platform technology) and user interfaces to facilitate interactive access to digital media in a lounge room setting. This paper provides an overview of an interdisciplinary design process applied by Australasian CRC for Interaction Design (ACID) researchers—in order to develop the device and present in detail its unique features.     

Performance evaluation for a transportation system in stochastic case

In a single-commodity multistate flow network, the arc capacity is stochastic and thus the system capacity (i.e. the maximum flow from the source to the sink) is not a fixed number. This paper constructs a multicommodity multistate flow network with weighted capacity allocation to model a transportation system. Each arc with cost attribute has several possible capacities. The capacity weight, the consumed amount of arc capacity by per commodity, varies with the arcs and types of commodity. We define the system capacity as a demand vector d if the system fulfills at most d. The addressed problem in this work is to measure the service quality of a transportation system. We propose a performance index, the probability that the upper bound of the system capacity equals a demand vector d subject to the budget constraint. A simple algorithm based on minimal cuts is presented to generate all (d,B)-MC that are the maximal capacity vectors meeting exactly the demand d under the budget B. The proposed performance index can be subsequently evaluated in terms of such (d,B)-MC.     

Building Bayesian networks for legal evidence with narratives: a case study evaluation

In a criminal trial, evidence is used to draw conclusions about what happened concerning a supposed crime. Traditionally, the three main approaches to modeling reasoning with evidence are argumentative, narrative and probabilistic approaches. Integrating these three approaches could arguably enhance the communication between an expert and a judge or jury. In previous work, techniques were proposed to represent narratives in a Bayesian network and to use narratives as a basis for systematizing the construction of a Bayesian network for a legal case. In this paper, these techniques are combined to form a design method for constructing a Bayesian network based on narratives. This design method is evaluated by means of an extensive case study concerning the notorious Dutch case of the Anjum murders.     

Usability evaluation of navigation tasks by people with intellectual disabilities: a Google and SAPO comparative study regarding different interaction modalities

Universal Access in the Information Society - This paper presents a case study regarding the usability evaluation of navigation tasks by people with intellectual disabilities. The aim was to...     

Gestural interaction and reading skills: a case study of people with Down syndrome

People with Down syndrome present cognitive difficulties that affect their reading skills. In this study, we present results about using gestural interaction with the Kinect sensor to improve the reading skills of students with Down syndrome. We found improvements in the visual association, visual comprehension, sequential memory, and visual integration after this stimulation in the experimental group compared to the control group. We also found that the number of errors and delay time in the interaction decreased between sessions in the experimental group.

     

基于Leap Motion和S曲线的飞行机器人机械臂控制研究

针对带有多自由度机械臂的飞行机器人,提出基于Leap Motion的控制方法以实现机械臂跟随人体手掌位置姿态运动的功能。采用DH方法建立了机械臂数学模型,给出了将Leap Motion获取的人手运动映射到机械臂末端的推导过程。利用7段S型曲线调速方法近似实现舵机角加速度连续没有突变,减轻了舵机快速响应给飞行器带来的冲击问题。设计制作了实物样机对控制方法的可实现性进行验证测试,在飞行测试中,成功地利用Leap Motion控制远端的机械臂抓取到地面目标。     

Performance visualization of a distributed system: a case study

The case study describes the use of a simple visualization technique to help resolve difficult performance problems in a large distributed system. The event trace data used was collected on a large distributed system built to run a benchmark of a complex securities trading application. The system was designed to handle several hundred transactions per second with subsecond response times. The complete benchmark workload consisted of several different types of transactions. For simplicity, the examples show only two types of transactions, representing about half the total workload     

Simulating the urban spatial structure with spatial interaction: A case study of urban polycentricity under different scenarios

Polycentric urban development is gaining momentum in both scholarly research and real-life practice. This brings new demand for planning support systems to simulate and analyse the urban spatial structure in terms of polycentricity under various urban policy scenarios. With the help of emerging urban data, urban simulation techniques, and network science, this study proposes a workflow to simulate the urban spatial structure with spatial interaction as a part of the planning support system. Using Singapore as a case study, this study has explored the resulting urban spatial structure with four employment distribution strategies. The results suggest that planning practices impact urban spatial structure and its spatial interaction by redistributing urban morphological elements, such as employment in this study. Also, our results show that the physical urban spatial structure and spatial interaction are closely related. These results reinforce the role of urban planning practice to achieve a more sustainable and coherent urban built environment. Through this empirical evidence, our workflow exemplifies the potential of the planning support system to help urban planners and governments understand their urban policy regarding urban polycentricity.     

Electronic paper display preferred viewing distance and character size for different age groups

This study explores the preferred viewing distance and character size for an electronic paper display for three age groups. Proofreading speed and accuracy ratio were measured during Chinese proofreading tests using the preferred character size and minimum acceptable character size. Data analysis showed that the mean preferred viewing distance for young, middle-aged and older groups was 503, 455 and 444 mm, respectively. The mean preferred character size determined by young, middle-aged and older groups was 42.0, 50.0 and 55.2 min arc, respectively. The proofreading test results indicated that the older group proofread significantly more slowly (1.25 word/sec) than the young (1.76 word/sec) and middle-aged groups (1.74 word/sec). Further, the participants proofread more correctly with their preferred character size (73.3%) than with their minimum acceptable character size (65.4%). This study provides valuable information for the design of Chinese text presentations for various age groups. STATEMENT OF RELEVANCE: This study confirmed the preferred viewing distance and character size for E-paper display were influenced by age. The preferred Chinese character size for young, middle-aged and older people was 42, 50 and 55 min arc, respectively. Therefore, the age factor should be considered for E-paper displays design and video display terminal (VDT) guidelines.     

Electronic paper display preferred viewing distance and character size for different age groups

This study explores the preferred viewing distance and character size for an electronic paper display for three age groups. Proofreading speed and accuracy ratio were measured during Chinese proofreading tests using the preferred character size and minimum acceptable character size. Data analysis showed that the mean preferred viewing distance for young, middle-aged and older groups was 503, 455 and 444 mm, respectively. The mean preferred character size determined by young, middle-aged and older groups was 42.0, 50.0 and 55.2 min arc, respectively. The proofreading test results indicated that the older group proofread significantly more slowly (1.25word/sec) than the young (1.76 word/sec) and middle-aged groups (1.74 word/sec). Further, the participants proofread more correctly with their preferred character size (73.3%) than with their minimum acceptable character size (65.4%). This study provides valuable information for the design of Chinese text presentations for various agegroups.

Statement of Relevance: This study confirmed the preferred viewing distance and character size for E-paper display were influenced by age. The preferred Chinese character size for young, middle-aged and older people was 42, 50 and 55 min arc, respectively. Therefore, the age factor should be considered for E-paper displays design and video display terminal (VDT) guidelines.     

Evaluation of visual feedback techniques for virtual grasping with bare hands using Leap Motion and Oculus Rift

Virtual Reality - Bare hand interaction (BHI) allows users to use their hands and fingers to interact with digital content without any attached devices or accessories. For BHI to realize widespread...     

Facilitating peripheral interaction: design and evaluation of peripheral interaction for a gesture-based lighting control with multimodal feedback

Most interactions with today’s interfaces require a person’s full and focused attention. To alleviate the potential clutter of focal information, we investigated how interactions could be designed to take place in the background or periphery of attention. This paper explores whether gestural, multimodal interaction styles of an interactive light system allow for this. A study compared the performance of interactions with the light system in two conditions: the central condition in which participants interacted only with the light system, and the peripheral condition in which they interacted with the system while performing a high-attentional task simultaneously. Our study furthermore compared different feedback styles (visual, auditory, haptic, and a combination). Results indicated that especially for the combination feedback style, the interaction could take place without participants’ full visual attention, and performance did not significantly decrease in the peripheral condition. This seems to indicate that these interactions at least partly took place in their periphery of attention and that the multimodal feedback style aided this process.     

SnapBlocks: a snapping interface for assembling toy blocks with XBOX Kinect

Toy blocks can help the children develop various skills, such as spatial, mathematical, creative problem solving etc. In this paper, we developed a computer aided system for child to play blocks with a computer in a natural and intuitive way using the Kinect. We design a set of intuitive body gestures that allow the user to naturally control and navigate 3D toy blocks in a virtual environment. To conquer the imprecise interaction with Kinect, we propose a snapping interface, which automatically computes the optimal location and orientation of the to-be-assembled block. This interface can significantly reduce the user’s burden for fine tuning the blocks at the desired locations, which is often tedious and time consuming. As a result, the user can fully immerse him/herself in the game and construct a complicated structure easily. The experimental results and positive feedback from users demonstrate the efficacy of our approach to virtual assembly of building blocks.     

Knowledge based evaluation of software systems: a case study

Solving software evaluation problems is a particularly difficult software engineering process and many contradictory criteria must be considered to reach a decision. Nowadays, the way that decision support techniques are applied suffers from a number of severe problems, such as naive interpretation of sophisticated methods and generation of counter-intuitive, and therefore most probably erroneous, results. In this paper we identify some common flaws in decision support for software evaluations. Subsequently, we discuss an integrated solution through which significant improvement may be achieved, based on the Multiple Criteria Decision Aid methodology and the exploitation of packaged software evaluation expertise in the form of an intelligent system. Both common mistakes and the way they are overcome are explained through a real world example.     

Optimal age and block replacement policies for a multi-component system with failure interaction

In this paper we consider a generalized age and block replacement policy for a multicomponent system with failure interaction. The i-th component (1 i N) has two types of failures. Type I and type II failures are age dependent. Type I failure (minor failure) is removed by a minimal repair, whereas type II failure (catastrophic failure) induces a total failure of the system (i.e. failure of all other components in the system) and is removed by an unplanned (or unscheduled) replacement of the system. For an age replacement maintenance policy, planned (or scheduled) replacements occur whenever an operating system reaches age T , whereas in the block replacement case, planned replacements occur every T units of time. The aim of this paper is to derive the expected long-run cost per unit time for each policy. The optimal T * which would minimize the cost rate is discussed. Various special cases are detailed. A numerical example is given to illustrate the method.