Distributed user interfaces in public spaces using RFID-based panels

The combination and integration of services between mobile computing and context-aware applications responds to the use of mobile devices defining a wide range of distributed user interfaces to support social activities. In this paper, we propose a novel solution that combines social software with context awareness to improve users' interaction in public spaces. This approach is based on the concept of collaborative interactive panels where users share their opinions and ideas about environmental issues by performing natural gestures. And so, taking advantage of physical resources already available in public spaces combined with the use of well-known technologies, such as mobile devices and RFID, we extend the concept of social software from the Web to physical public scenarios, such as bus stations, squares, etc. As an example, we present a case of study that encourage citizens' participation in decisions related to the community environmental issues reducing the gap between the social software and users.     

UX Curve: A method for evaluating long-term user experience

The goal of user experience design in industry is to improve customer satisfaction and loyalty through the utility, ease of use, and pleasure provided in the interaction with a product. So far, user experience studies have mostly focused on short-term evaluations and consequently on aspects relating to the initial adoption of new product designs. Nevertheless, the relationship between the user and the product evolves over long periods of time and the relevance of prolonged use for market success has been recently highlighted. In this paper, we argue for the cost-effective elicitation of longitudinal user experience data. We propose a method called the “UX Curve” which aims at assisting users in retrospectively reporting how and why their experience with a product has changed over time. The usefulness of the UX Curve method was assessed in a qualitative study with 20 mobile phone users. In particular, we investigated how users’ specific memories of their experiences with their mobile phones guide their behavior and their willingness to recommend the product to others. The results suggest that the UX Curve method enables users and researchers to determine the quality of long-term user experience and the influences that improve user experience over time or cause it to deteriorate. The method provided rich qualitative data and we found that an improving trend of perceived attractiveness of mobile phones was related to user satisfaction and willingness to recommend their phone to friends. This highlights that sustaining perceived attractiveness can be a differentiating factor in the user acceptance of personal interactive products such as mobile phones. The study suggests that the proposed method can be used as a straightforward tool for understanding the reasons why user experience improves or worsens in long-term product use and how these reasons relate to customer loyalty.     

A weight-aware channel assignment algorithm for mobile multicast in wireless mesh networks

Wireless mesh networks (WMNs) are one of key technologies for next generation wireless networks. In this paper, we propose a heuristic channel assignment algorithm with weight awareness to support mobile multicast in WMNs. To enhance network throughput, our algorithm is based on the path forwarding weight to perform channel assignment. In addition to non-overlapping channels, partially-overlapping channels are also used in channel assignment. To fully exploit all available channels in channel assignment, we devise a new channel selection metric to consider the channel separation and the distance between nodes. In mobile multicast, the multicast tree structure cannot be fixed due to receiver (multicast member) mobility. The change of the multicast tree structure will result in channel re-assignment. The proposed algorithm is based on a critical-event driven manner to reduce the times of channel re-assignment as much as possible. Finally, we perform simulation experiments to show the effectiveness of the proposed channel assignment algorithm.     

A rapid prototyping software infrastructure for user interfaces in ubiquitous augmented reality

Recent user interface concepts, such as multimedia, multimodal, wearable, ubiquitous, tangible, or augmented-reality-based (AR) interfaces, each cover different approaches that are all needed to support complex human–computer interaction. Increasingly, an overarching approach towards building what we call ubiquitous augmented reality (UAR) user interfaces that include all of the just mentioned concepts will be required. To this end, we present a user interface architecture that can form a sound basis for combining several of these concepts into complex systems. We explain in this paper the fundamentals of DWARFs user interface framework (DWARF standing for distributed wearable augmented reality framework) and an implementation of this architecture. Finally, we present several examples that show how the framework can form the basis of prototypical applications.     

: a toolset for creating customized interfaces for grid user communities

is a comprehensive set of tools for creating customized graphical user interfaces (GUIs). It draws from the concept of computing portals, which are here seen as interfaces to application-specific computing services for user communities. While was originally designed for the use in computational grids, it can be used in client/server environments as well.Compared to other GUI generators, is more versatile and more portable. It can be employed in many different application domains and on different target platforms. With , application experts (rather than computer scientists) are able to create their own individually tailored GUIs.     

A multi-formalism approach for model-based dynamic distribution of user interfaces of critical interactive systems

Evolution in the context of use requires evolutions in the user interfaces even when they are currently used by operators. User Centered Development promotes reactive answers to this kind of evolutions either by software evolutions through iterative development approaches or at runtime by providing additional information to the operators such as contextual help for instance. This paper proposes a model-based approach to support proactive management of context of use evolutions. By proactive management we mean mechanisms in place to plan and implement evolutions and adaptations of the entire user interface (including behaviour) in a generic way. The approach proposed handles both concentration and distribution of user interfaces requiring both fusion of information into a single UI or fission of information into several ones. This generic model-based approach is exemplified on a safety critical system from space domain. It presents how the new user interfaces can be generated at runtime to provide a new user interface gathering in a single place all the information required to perform the task. These user interfaces have to be generated at runtime as new procedures (i.e. sequences of operations to be executed in a semi-autonomous way) can be defined by operators at any time in order to react to adverse events and to keep the space system in operation. Such contextual, activity-related user interfaces complement the original user interfaces designed for operating the command and control system. The resulting user interface thus corresponds to a distribution of user interfaces in a focus+context way improving usability by increasing both efficiency and effectiveness.     

Control centric approach in designing scrolling and zooming user interfaces

The dynamic systems approach to the design of continuous interaction interfaces allows the designer to use simulations, and analytical tools to analyse the behaviour and stability of the controlled system alone and when it is coupled with a manual control model of user behaviour. This approach also helps designers to calibrate and tune the parameters of the system before the actual implementation, and in response to user feedback. In this work we provide a dynamic systems interpretation of the coupling of internal states involved in speed-dependent automatic zooming, and test our implementation on a text browser on a Pocket PC instrumented with a tilt sensor. We illustrate simulated and experimental results of the use of the proposed coupled navigation and zooming interface using tilt and touch screen input.     

To model objects in information systems and user interfaces: implications for object-oriented methods

Abstract. A general way of contrasting the object-oriented to the function-oriented approach, called 'object-order' and 'function-order', is proposed in this paper. In addition, when modelling information systems, there is a third principle of ordering, 'subject-order'. Object and function-order are used to define the two approaches to modelling information systems and in human-computer interaction, in ways that are compatible to the corresponding distinction in programming. The conditions for selecting either of the two approaches are, however, not discussed here.
By means of an object-ordered method, e.g. Jackson System Development (JSD), an object-ordered model is produced, and the user interface that can be derived from the model is object-ordered too. However, other guidelines in JSD support subject-order. A function-ordered interface can be derived from the subject-ordered model. A computer system designed by means of an object-organized method may therefore obtain an interface that is partially object-ordered and partially function-ordered. Other object-oriented methods give guidelines for designing function-oriented interfaces without relating these guidelines to the model.
The system designer may benefit from having three principles of ordering when modelling a system. However, a user may be confused by an interface that sometimes gives preference to objects, sometimes to functions.     

Improving densely deployed wireless network performance in unlicensed spectrum through hidden-node aware channel assignment

It is well known that a wireless local area network (WLAN) based on the IEEE 802.11 standard suffers from interference and scalability problems due to the limited number of non-overlapping channels. In order to mitigate the interference problem, channel assignment algorithms has been a popular research topic in recent years. It has been shown that such algorithms can greatly reduce the interference among wireless access points. However, in this paper, we show that previously proposed channel assignment algorithms may lead to an increased number of hidden nodes in dense network deployments. We also show that this can significantly decrease the performance of the network. Furthermore, we present results from experiments showing that the Request to send (RTS)/Clear to send (CTS) mechanism is unable to solve the hidden node problem in infrastructure WLANs, and therefore careful consideration needs to be taken when choosing channel assignment strategies in densely deployed wireless networks. To this end, we propose both a centralized channel assignment algorithm and a distributed channel assignment algorithm. Using a simulation study, we show that the proposed algorithms can outperform traditional channel assignment in densely deployed scenarios, in terms of QoS sensitive VoIP support without compromising the aggregate throughput, and that they are therefore a better performing alternative in such settings.     

Adaptive channel assignment scheme for wireless networks

In this paper, an adaptive channel assignment scheme is proposed to ensure the quality of services for the wireless networks. The proposed scheme divides the channels into two categories, the guard channels and the shared channels. The number of guard channels is estimated by the Markovian model in order to keep the handoff calls higher priority. The remaining channels, called shared channels, can be used by both new calls and handoff calls. The proposed scheme based on incoming rates of handoff and new calls allocates channels for guard and shared channels. In addition, this approach is able to provide quality of service guarantee in terms of handoff dropping rate. From the simulation, the proposed scheme significantly improves the dropping rate and the blocking rate in comparison with the existing methods.     

Enhanced ergonomics approaches for product design: a user experience ecosystem perspective and case studies

This paper first discusses the major inefficiencies faced in current human factors and ergonomics (HFE) approaches: (1) delivering an optimal end-to-end user experience (UX) to users of a solution across its solution lifecycle stages; (2) strategically influencing the product business and technology capability roadmaps from a UX perspective and (3) proactively identifying new market opportunities and influencing the platform architecture capabilities on which the UX of end products relies. In response to these challenges, three case studies are presented to demonstrate how enhanced ergonomics design approaches have effectively addressed the challenges faced in current HFE approaches. Then, the enhanced ergonomics design approaches are conceptualised by a user-experience ecosystem (UXE) framework, from a UX ecosystem perspective. Finally, evidence supporting the UXE, the advantage and the formalised process for executing UXE and methodological considerations are discussed.

Practitioner Summary: This paper presents enhanced ergonomics approaches to product design via three case studies to effectively address current HFE challenges by leveraging a systematic end-to-end UX approach, UX roadmaps and emerging UX associated with prioritised user needs and usages. Thus, HFE professionals can be more strategic, creative and influential.     

Examining mobile instant messaging user loyalty from the perspectives of network externalities and flow experience

Due to the intense competition and low switching cost, building user loyalty is critical for mobile instant messaging (IM) service providers. Integrating both perspectives of network externalities and flow experience, this research identified the factors affecting mobile IM user loyalty. Network externalities include referent network size and perceived complementarity. Flow experience includes perceived enjoyment and attention focus. We conducted data analysis with structural equation modeling (SEM). The results show that both network externalities and flow experience significantly affect perceived usefulness and satisfaction, further determining user loyalty. Thus mobile service providers need to improve their IM platforms, and deliver positive network externalities and good usage experience to users. Then they can facilitate users’ loyalty.     

A neural network-based approach for user experience assessment

The objective of this study is to approximate the links between user satisfaction and its determinants without having the restrictions of common statistical procedures such as linearity, symmetry and normality. For this reason, artificial neural networks are utilised and trained with the observations of an extensive survey on user satisfaction with respect to website attributes. Each observation includes evaluations about the performance of 18 specific and 9 general website attributes as well as an evaluation about overall user satisfaction. The analysis results indicate that website attributes present different impacts on satisfaction whereas the relationships found feature both asymmetry and nonlinearity. Finally, function approximation using neural networks is found to be appropriate for estimating such kind of relationships providing valuable information about satisfaction's formation.     

An inexpensive unstructured platform for wireless mobile peer-to-peer networks

In this paper, we propose an unstructured platform, namely I nexpensive P eer-to- P eer S ubsystem (IPPS), for wireless mobile peer-to-peer networks. The platform addresses the constraints of expensive bandwidth of wireless medium, and limited memory and computing power of mobile devices. It uses a computationally-, memory requirement- and communication- wise inexpensive gossip protocol as the main maintenance operation, and exploits location information of the wireless nodes to minimize the number of link-level messages for communication between peers. As a result, the platform is not only lightweight by itself, but also provides a low cost framework for different peer-to-peer applications. In addition, further enhancements are introduced to enrich the platform with robustness and tolerance to failures without incurring any additional computational and memory complexity, and communication between peers. In specific, we propose schemes for a peer (1) to chose a partner for a gossip iteration, (2) to maintain the neighbors, and (3) to leave the peer-to-peer network. Simulation results are given to demonstrate the performance of the platform.

Design for experience innovation: understanding user experience in new product development

In providing a better experience to users in terms of product usage, we focus on the important concept of a user-centred design (UCD), and explore a new approach to user experience (UX), with the effort to understand experience-driven innovation. Based on the conceptual framework of experiential network and the results of multiple case studies covering 643 successfully designed products or services providing an optimised UX, we categorise the UX context into the following four representative types: individualisation, combination, integration, and ecosystem. Furthermore, we identify the essential UCD concepts that reflect the core needs and expectations of users in each of the designed contexts, that is, specialty, usefulness, usability, and fluency. Finally, we discuss the dynamic concepts that help achieve a successful experience innovation. We expect these findings to play a crucial role in the development of novel design concepts or strategies, not only to better understand the needs of contemporary users, but also to better understand the dynamics of innovation.     

Fuzzy extended Kalman filter for dynamic mobile localization in urban area using wireless network

The problem of accurate mobile positioning in cellular network is very challenging and still subject to intensive research, especially given the uncertainty pervading the signal strength measurements. This paper advocates the use of fuzzy based reasoning in conjunction with Kalman filtering like approach in order to enhance the localization accuracy. The methodology uses TEMS Investigation software to retrieve network information including signal strength and cell-identities of various base transmitter stations (BTS). The distances from the mobile station (MS) to each BTS are therefore generated using Walfish-Ikigami radio propagation model. The performances of the established hybrid estimator −fuzzy extended Kalman filter (FEKF)- are compared with extended Kalman filter approach and fuzzy-control based approach. Both simulation and real-time testing results demonstrate the feasibility and superiority of the FEKF localization based approach.     

无线泛在网络环境下用户环境感知关键技术研究

在阐述了无线泛在网络概念的基础上,通过分析无线泛在网络环境下用户环境感知的内涵,针对无线泛在网络环境下用户环境感知关键技术进行了研究,提出了用户环境感知信息存取、用户环境感知信息建模表示、用户环境感知信息存储、用户环境感知信息交互控制机制、用户环境感知信息推理利用以及用户环境感知信息安全等关键技术的解决方案。     

多方式复合城市交通网络弹性需求随机用户平衡分配模型

为解决目前交通分配模型仅限于某种方式内,并缺少考虑方式划分与交通分配相互影响的问题,描述了多方式复合城市交通网络。网络中涵盖了公交车和小汽车两个子系统,出行总量满足弹性需求,并根据两个子系统效用函数进行随机用户平衡分配,同时子系统内各路径流量分配也满足随机用户平衡,从而建立了两层次三随机用户平衡的多方式复合城市交通网络弹性需求随机用户平衡分配模型。证明了模型解的等价性及唯一性;提出了综合对角化算法和MSA算法的组合求解算法。最后,设计了一个算例以验证模型有效性,计算结果为:公交车出行量为814.1人次/h,占总出行量3997.8人次/h的20.36%,小汽车出行量占79.64%。表明该模型在计算网络中各路段流量的同时,也可得出各交通方式的比重。     

A smart node architecture for adding mobility to wireless sensor networks

Adding a few mobile nodes into the conventional wireless sensor networks can greatly improve the sensing and control capabilities of the networks and can help researchers solve many challenges such as network deployment and repair. This paper presents an enhanced node architecture for adding controlled mobility to wireless sensor networks. The structural model, the power model and the networking model of the proposed mobile node have been built respectively for better node control. And it provides a novel robotic platform for experimental research in hybrid sensor networks or other distributed measurement and control systems. A testbed has finally been created for validating the basic functions of the proposed mobile sensor node. The results of a coverage experiment show that the mobile node can provide additional support for network coverage and can ensure that the sensor network will work properly in undesirable environments.     

可证安全的面向无线传感器网络的双因素认证方案

随着无线传感器网络的快速发展,对外部用户的身份进行确认已成为获取传感器网络中实时数据所要解决的关键问题。基于Nam提出的首个广泛适用于面向无线传感器网络的双因素认证方案的安全模型,设计了一个新的可证安全的用户认证密钥协商方案。该方案基于椭圆曲线密码体制,达到用户、网关节点及传感器节点之间的双向认证,满足匿名性并建立会话密钥,最后基于ECCDH困难性假设证明了新方案的安全性。与Nam提出的方案相比,在满足安全性的同时,将参与者的计算效率达到最优,更符合资源受限环境及现实应用。