The design and evaluation of a photograph-sharing application for rural and urban Kenyan families

Family members in Kenya rely on technology to connect between rural and urban regions, yet little is known about the specific communication challenges they face and how to overcome them through new communication technology design. To explore this topic, we conducted two studies along with design work. First, we conducted an interview-based study that explores how families in Kenya currently used communication technology and the social and technical challenges that they faced in doing so. Our findings showed that family communication focuses on economic support, well-being, and the everyday coordination of activities, yet infrastructure challenges, reduced access to technology, and social situations created communication challenges. Second, we used these results to inform the design and deployment of a system called TumaPicha that supports the sharing of photographs between families who live in rural and low-income urban areas via intermediaries. The goal of the system was to support communication around economic activities while easing issues around connectivity and technology literacy. Third, TumaPicha was deployed over a period of 5 weeks with families in Kenya whose members inhabited both rural and low-income urban areas. Deployment results reveal that families used photographs to share knowledge related to subsistence awareness, village awareness, and health and well-being awareness. This suggests promise for simple media sharing applications in developing countries like Kenya that rely on a mixture of technology and social processes; however, our study also raises challenging questions around privacy and power consumption with new devices and applications.     

视觉化协同超媒体及其在合作学习中的应用

在分布式合作学习环境中,学生和老师需要一个共享的信息空间去与学习材料交互作用,并从中知晓合作者的存在及其活动.学生和老师还需要一些协同和通信手段去协调他们共同的活动.为此,提出了一种视觉化协同超媒体技术.它可以提供所需的共享信息空间.在此空间中,形象的超媒体对象既可以表示学习材料(学习内容),又可以表示学习过程(学习方法).这种协同超媒体集成了灵活的过程支持、通信渠道以及文件处理功能.因而,它可以支持学生(和老师)按一定的学习方法并通过文字或声音渠道去协调他们共同的学习活动.这种协同超媒体可以通过万维网(浏览器)访问.为了揭示这种技术的实用性,还给出了一个案例和一些用户体验.     

Guest Editors' Introduction: 3D Documents

Digital libraries (DLs) in general and technical or cultural preservation applications in particular offer a rich set of multimedia objects like audio, music, images, videos, and also 3D models. However, instead of handling these objects consistently as regular documents - in the same way we treat textual documents - most applications handle them differently. Considering that textual documents are only one media type among many, it's clear that this type of document is handled quite specially. A full-text search engine lets users retrieve a specific document based on its content - that is, one or more words that appear in it. Content-based retrieval of other media types is an active research area, and in the case of 3D documents, only pilot applications exist.     

Composition and role of convergent technological repertoires in audiovisual media consumption

This mixed-method research focuses on the growing appropriation of multiple screen devices for audiovisual media consumption. Based on survey measures, we distinguish three patterns: (a) maintaining the status quo, by mainly drawing upon television, (b) broadening up the repertoire, by extending television with computers and mobile devices, or (c) even replacing television by a computer. Next, we draw upon insights from niche theory, rationalising media choices in terms of competing gratifications. This perspective is however too one-sided, as our results indicate that habit is a much stronger explanatory variable, especially when a broad range of devices are appropriated. In a follow-up qualitative study, based on Q-methodology, we found that the orientations towards what people seek in audiovisual technologies are only mildly contingent with specific technology appropriation. This problematises the very substance of niches in the audiovisual: as technologies are capable of the same benefits, their discriminating power is declining. Hence, in future applications of niche theory, gratifications and habits of communication modes (what people do with media technologies) should be taken into account, rather than media as tied to a specific technology. Niche theory's core remains, but its applications should be updated to theoretical insights matching the evolving media environment.     

Design and implementation of the secure compiler and virtual machine for developing secure IoT services

Recent years have seen the development of computing environments for IoT (Internet of Things) services, which exchange large amounts of information using various heterogeneous devices that are always connected to networks. Since the data communication and services occur on a variety of devices, which not only include traditional computing environments and mobile devices such as smartphones, but also household appliances, embedded devices, and sensor nodes, the security requirements are becoming increasingly important at this point in time. Already, in the case of mobile applications, security has emerged as a new issue, as the dissemination and use of mobile applications have been rapidly expanding. This software, including IoT services and mobile applications, is continuously exposed to malicious attacks by hackers, because it exchanges data in the open Internet environment. The security weaknesses of this software are the direct cause of software breaches causing serious economic loss. In recent years, the awareness that developing secure software is intrinsically the most effective way to eliminate the software vulnerability, rather than strengthening the security system of the external environment, has increased. Therefore, methodology based on the use of secure coding rules and checking tools is attracting attention to prevent software breaches in the coding stage to eliminate the above vulnerabilities. This paper proposes a compiler and a virtual machine with secure software concepts for developing secure and trustworthy services for IoT environments. By using a compiler and virtual machine, we approach the problem in two stages: a prevention stage, in which the secure compiler removes the security weaknesses from the source code during the application development phase, and a monitoring stage, in which the secure virtual machine monitors abnormal behavior such as buffer overflow attacks or untrusted input data handling while applications are running.     

A user-centric network communication broker for multimedia collaborative computing

The development of collaborative multimedia applications today follows a vertical development approach, where each application is built on top of low-level network abstractions such as the socket interface. This stovepipe development process is a major inhibitor that drives up the cost of development and slows down the innovation pace of new generations of communication applications. In this paper, we propose a network communication broker (NCB) that provides a unified higher-level abstraction for the class of multimedia collaborative applications. We demonstrate how NCB encapsulates the complexity of network-level communication control and media delivery, and expedites the development of applications with various communication logics. We investigate the minimum necessary requirements for the NCB abstraction. We identify that the concept of user-level sessions involving multiple parties and multiple media, is critical to designing a reusable NCB to facilitate next-generation multimedia communications. Furthermore, the internal design of NCB decouples the user-level sessions from network-level sessions, so that the NCB framework can accommodate heterogeneous networks, and applications can be easily ported to new network environments. In addition, we demonstrate how the extensible and self-managing design of NCB supports dynamic adaptation in response to changes in network conditions and user requirements.     

Evaluating Shared Access: social equality and the circulation of mobile phones in rural Uganda

This article examines forms of shared access to technology where some privileges of ownership are retained. Sharing is defined as informal, non-remunerative resource distributing activities where multiple individuals have a relationship to a single device as purchaser, owner, possessor, operator and/or user. In the specific case of mobile phones in rural Uganda, dynamics of social policing and social obligation were mediated and concretized by these devices. Patterns of sharing mobile phones in rural Uganda led to preferential access for needy groups (such as those in ill health) while systematically and disproportionately excluding others (women in particular). The framework for sharing proposed in this article will be useful for structuring comparisons of technology adoption and access across cultural contexts.     

Collaborative design: Improving efficiency by concurrent execution of Boolean tasks

Computer-Aided Design (CAD) applications provide design and engineering professionals with various computer-based tools to perform design activities. As efficiency is one of the most important requirements in most design tasks, in this article, we contribute a novel collaborative design approach to improving efficiency, where a complex design task can be divided and executed concurrently by multiple collaborative designers. This approach is particularly effective for design tasks where Boolean operations – widely supported by most CAD applications – are heavily used in design activities, such as architecture design, mechanical design and digital media design. We have designed and implemented a prototype system CoAutoCAD to test the approach and to demonstrate a variety of collaborative design activities.     

Using digital but physical surrogates to mediate awareness, communication and privacy in media spaces

Digital but physical surrogates are tangible representations of remote people (typically members of small intimate teams), positioned within an office and under digital control. Surrogates selectively collect and present awareness information about the people they represent. They also react to people's explicit and implicit physical actions: a person's explicit acts include grasping and moving them, while their implicit acts include how they move towards or away from the surrogate. By responding appropriately to these physical actions of people, surrogates can control the communication capabilities of a media space in a natural way. Surrogates also balance awareness and privacy by limiting and abstracting how activities are portrayed, and by offering different levels of salience to its users. The combination of all these attributes means that surrogates can make it easy for intimate collaborators to move smoothly from awareness of each other to casual interaction while mitigating privacy and distraction concerns.Exploring different surrogate designs and how they work together can be straightforward if a good infrastructure is in place. We use anawareness server based on a distributed model-view-controller architecture, which automatically captures, stores and distributes events. We also package surrogates as physical widgets orphidgets with a well-defined interface; this makes it easy for a programmer to plug a surrogate into the awareness server as a controller (to generate awareness events), or view (to display events that others have produced), or both. Because surrogate design, implementation and use is still a new discipline, we also present several issues and next steps.     

Storage allocation policies for time-dependent multimedia data

Multimedia computing requires support for heterogeneous data types with differing storage, communication and delivery requirements. Continuous media data types, such as audio and video, impose delivery requirements that are not satisfied by conventional physical storage organizations. In this paper, we describe a physical organization for multimedia data based on the need to support the delivery of multiple playout sessions from a single rotating-disk storage device. Our model relates disk characteristics to the different media recording and playback rates and derives their storage pattern. This storage organization guarantees that as long as a multimedia delivery process is running, starvation will never occur. Furthermore, we derive bandwidth and buffer constraints for disk access and present an approach to minimize latencies for non-continuous media stored on the same device. The analysis and numerical results indicate the feasibility of using conventional rotating magnetic disk storage devices to support multiple sessions for video-on-demand applications     

Multimedia Clip Generation From Documents for Browsing on Mobile Devices

Small displays on mobile handheld devices, such as personal digital assistants (PDAs) and cellular phones, are the bottlenecks for usability of most content browsing applications. Generally, conventional content such as documents and Web pages need to be modified for effective presentation on mobile devices. This paper proposes a novel visualization for documents, called multimedia thumbnails, which consists of text and image content converted into playable multimedia clips. A multimedia thumbnail utilizes visual and audio channels of small portable devices as well as both spatial and time dimensions to communicate text and image information of a single document. The proposed algorithm for generating multimedia thumbnails includes 1) a semantic document analysis step, where salient content from a source document is extracted; 2) an optimization step, where a subset of this extracted content is selected based on time, display, and application constraints; and 3) a composition step, where the selected visual and audible document content is combined into a multimedia thumbnail. Scalability of MMNails that allows generation of multimedia clips of various lengths is also described. A user study is presented that evaluates the effectiveness of the proposed multimedia thumbnail visualization.     

Busy families’ awareness needs

This work examines how awareness systems, a class of technologies that support sustained and effortless communication between individuals and groups, can support family communication. Going beyond the evaluation of specific design concepts, this paper reports on three studies that aimed to answer the following research questions: (a) Do families want to be aware of each other through the day? Or, would they perhaps rather not know more about each other's activities and whereabouts than they already do? (b) If they do wish to have some awareness, what should they be aware of? The research involved in-depth interviews with 20 participants, a field trial of an awareness system connecting five “busy” parents with their children and a survey of 69 participants conducted over the web. Triangulation of the results of the three studies leads to the following conclusions: (a) Some busy parents want to automatically exchange awareness information during the day while others do not. (b) Availability of partner for coordinating family activities, daily activities in new family situations, activity, and location information of dependent children are salient awareness information needs for this group. (c) Awareness information needs to vary with contexts, suggesting the need for flexible mechanisms to manage the sharing of such information.     

Context-aware design of adaptable multimodal documents

In this paper we present a model and an adaptation architecture for context-aware multimodal documents. A compound virtual document describes the different ways in which multimodal information can be structured and presented. Physical features are associated to media instances, while properties describe the context. Concrete documents are instantiated from virtual documents by selecting and synchronizing proper media instances based on the user context: the situation, the environment, the device and the available communication resources. The relations between the context features and the media properties are described by a rule based system.     

Joint learning and optimization for Federated Learning in NOMA-based networks

Over the past decade, the usage of machine learning (ML) techniques have increased substantially in different applications. Federated Learning (FL) refers to collaborative techniques that avoid the exchange of raw data between the nodes in a distributed training task. This addresses important issues such as data privacy, energy consumption, and the limited availability of clean spectral slots. In this work, we investigate the performance of FL updates with edge devices connected to a leading device (LD) with practical wireless links, where uplink updates from the edge devices to the LD are shared without orthogonalizing the resources. In particular, we adopt a non-orthogonal multiple access (NOMA) uplink scheme, and analytically investigate its effect on the convergence round (CR) and the accuracy of the FL model. Moreover, we formulate an optimization problem that aims at minimizing the CR, and further guarantees communication fairness between the users while considering the per-device energy consumption figures and the accuracy of the realized global FL model. Monte-Carlo simulations prove the reliability of our derived analytical expressions and reveal the importance of adopting a joint optimization approach that demonstrates a significant reduction in communication latency, while taking into account user fairness in the NOMA network, improving the energy consumption figures and yielding acceptable accuracy levels when compared with several baselines.     

Interactive multi-frame reconstruction for mobile devices

The small size of handheld devices, their video capabilities and multiple cameras are under-exploited assets. Properly combined, the features can be used for creating novel applications that are ideal for pocket-sized devices, but may not be useful in laptop computers, such as interactively capturing and analyzing images on the fly. In this paper we consider building mosaic images of printed documents and natural scenes from low resolution video frames. High interactivity is provided by giving a real-time feedback on the video quality, while simultaneously guiding the user’s actions. In our contribution, we analyze and compare means to reach interactivity and performance with sensor signal processing and GPU assistance. The viability of the concept is demonstrated on a mobile phone. The achieved usability benefits suggest that combining interactive imaging and energy efficient high performance computing could enable new mobile applications and user interactions.     

Query Decomposition for a Distributed Object-Oriented Mediator System

The mediator-wrapper approach to integrate data from heterogeneous data sources has usually been centralized in the sense that a single mediator system is placed between a number of data sources and applications. As the number of data sources increases, the centralized mediator architecture becomes an administrative and performance bottleneck. This paper presents a query decomposition algorithm for a distributed mediation architecture where the communication among the mediators is on a higher level than the communication between a mediator and a data source. Some of the salient features of the proposed approach are: (i) exploring query execution schedules that contain data flow to the sources, necessary when integrating object-oriented sources that provide services (programs) and not only data; (ii) handling of functions with multiple implementations at more than one mediator or source; (iii) multi-phase query decomposition using a combination of heuristics and cost-based strategies; (iv) query plan tree rebalancing by distributed query recompilation.