6,761 research outputs found
Millimeter-wave Wireless LAN and its Extension toward 5G Heterogeneous Networks
Millimeter-wave (mmw) frequency bands, especially 60 GHz unlicensed band, are
considered as a promising solution for gigabit short range wireless
communication systems. IEEE standard 802.11ad, also known as WiGig, is
standardized for the usage of the 60 GHz unlicensed band for wireless local
area networks (WLANs). By using this mmw WLAN, multi-Gbps rate can be achieved
to support bandwidth-intensive multimedia applications. Exhaustive search along
with beamforming (BF) is usually used to overcome 60 GHz channel propagation
loss and accomplish data transmissions in such mmw WLANs. Because of its short
range transmission with a high susceptibility to path blocking, multiple number
of mmw access points (APs) should be used to fully cover a typical target
environment for future high capacity multi-Gbps WLANs. Therefore, coordination
among mmw APs is highly needed to overcome packet collisions resulting from
un-coordinated exhaustive search BF and to increase the total capacity of mmw
WLANs. In this paper, we firstly give the current status of mmw WLANs with our
developed WiGig AP prototype. Then, we highlight the great need for coordinated
transmissions among mmw APs as a key enabler for future high capacity mmw
WLANs. Two different types of coordinated mmw WLAN architecture are introduced.
One is the distributed antenna type architecture to realize centralized
coordination, while the other is an autonomous coordination with the assistance
of legacy Wi-Fi signaling. Moreover, two heterogeneous network (HetNet)
architectures are also introduced to efficiently extend the coordinated mmw
WLANs to be used for future 5th Generation (5G) cellular networks.Comment: 18 pages, 24 figures, accepted, invited paper
Computer-Supported Collaborative Production
This paper proposes the concept of collaborative production as a focus of concern within the general area of collaborative work. We position the concept with respect to McGrath's framework for small group dynamics and the more familiar collaboration processes of awareness, coordination, and communication (McGrath 1991). After reviewing research issues and computer-based support for these interacting aspects of collaboration, we turn to a discussion of implications for how to design improved support for collaborative production. We illustrate both the challenges of collaborative production and our design implications with a collaborative map-updating scenario drawn from the work domain of geographical information systems
Microservice API Evolution in Practice: A Study on Strategies and Challenges
Nowadays, many companies design and develop their software systems as a set
of loosely coupled microservices that communicate via their Application
Programming Interfaces (APIs). While the loose coupling improves
maintainability, scalability, and fault tolerance, it poses new challenges to
the API evolution process. Related works identified communication and
integration as major API evolution challenges but did not provide the
underlying reasons and research directions to mitigate them. In this paper, we
aim to identify microservice API evolution strategies and challenges in
practice and gain a broader perspective of their relationships. We conducted 17
semi-structured interviews with developers, architects, and managers in 11
companies and analyzed the interviews with open coding used in grounded theory.
In total, we identified six strategies and six challenges for REpresentational
State Transfer (REST) and event-driven communication via message brokers. The
strategies mainly focus on API backward compatibility, versioning, and close
collaboration between teams. The challenges include change impact analysis
efforts, ineffective communication of changes, and consumer reliance on
outdated versions, leading to API design degradation. We defined two important
problems in microservice API evolution resulting from the challenges and their
coping strategies: tight organizational coupling and consumer lock-in. To
mitigate these two problems, we propose automating the change impact analysis
and investigating effective communication of changes as open research
directions
A Taxonomy of Data Grids for Distributed Data Sharing, Management and Processing
Data Grids have been adopted as the platform for scientific communities that
need to share, access, transport, process and manage large data collections
distributed worldwide. They combine high-end computing technologies with
high-performance networking and wide-area storage management techniques. In
this paper, we discuss the key concepts behind Data Grids and compare them with
other data sharing and distribution paradigms such as content delivery
networks, peer-to-peer networks and distributed databases. We then provide
comprehensive taxonomies that cover various aspects of architecture, data
transportation, data replication and resource allocation and scheduling.
Finally, we map the proposed taxonomy to various Data Grid systems not only to
validate the taxonomy but also to identify areas for future exploration.
Through this taxonomy, we aim to categorise existing systems to better
understand their goals and their methodology. This would help evaluate their
applicability for solving similar problems. This taxonomy also provides a "gap
analysis" of this area through which researchers can potentially identify new
issues for investigation. Finally, we hope that the proposed taxonomy and
mapping also helps to provide an easy way for new practitioners to understand
this complex area of research.Comment: 46 pages, 16 figures, Technical Repor
A Typology of Virtual Teams: Implications for Effective Leadership
As the nature of work in today\u27s organizations becomes more complex, dynamic, and global, there has been an increasing emphasis on far-flung, distributed, virtual teams as organizing units of work. Despite their growing prevalence, relatively little is known about this new form of work unit. The purpose of this paper is to present a theoretical framework to focus research toward understanding virtual teams and, in particular, to identify implications for effective leadership. Specifically, we focus on delineating the dimensions of a typology to characterize different types of virtual teams. First, we distinguish virtual teams from conventional teams to identify where current knowledge applies and new research needs to be developed. Second, we distinguish among different types of virtual teams, considering the critical role of task complexity in determining the underlying characteristics of virtual teams and leadership challenges the different types entail. Propositions addressing leadership implications for the effective management of virtual teams are proposed and discussed
Improving groupware design for loosely coupled groups
Loosely coupled workgroups are common in the real world, and workers in these groups are autonomous and weakly interdependent. They have patterns of work and collaboration that distinguish them from other types of groups, and groupware systems that are designed to support loose coupling must address these differences. However, they have not been studied in detail in Computer-Supported Cooperative Work (CSCW), and the design process for these groups is currently underspecified. This forces designers to start from scratch each time they develop a system for loosely coupled groups, and they must approach new work settings with little information about how work practices are organized.
In this dissertation, I present a design framework to improve the groupware design process for loosely coupled workgroups. The framework has three main parts that add a new layer of support to each of the three stages in the general groupware design process: data collection about the target work setting, analysis of the data, and system design based on the analysis results. The framework was developed to provide designers with support during each of these stages so that they can consider important characteristics of loosely coupled work practice while carrying out design for the target group. The design framework is based on information from CSCW and organizational research, and on real-world design experiences with one type of loosely coupled workgroup—home care treatment teams.
The framework was evaluated using observations, interviews, and field trials that were carried out with multidisciplinary home care treatment teams in Saskatoon Health Region. A series of field observations and interviews were carried out with team members from each of the home care disciplines. The framework was then used to develop Mohoc, a groupware system that supports work in home care. Two field trials were carried out where the system was used by teams to support their daily activities. Results were analyzed to determine how well each part of the design framework performed in the design process. The results suggest that the framework was able to fill its role in specializing the general CSCW design process for loosely coupled groups by adding consideration for work and collaboration patterns that are seen in loosely coupled settings. However, further research is needed to determine whether these findings generalize to other loosely coupled workgroups
Supporting public availability and accessibility with Elvin: experiences and reflections.
We provide a retrospective account of how a generic event notification service called Elvin and a suite of simple client applications: CoffeeBiff, Tickertape and Tickerchat, came to be used within our organisation to support awareness and interaction. After overviewing Elvin and its clients, we outline various experiences from data collated across two studies where Elvin and its clients have been used to augment the workaday world to support interaction, to make digital actions visible, to make physical actions available beyond the location of action, and to support content and socially based information filtering. We suggest there are both functional and technical reasons for why Elvin works for enabling awareness and interaction. Functionally, it provides a way to produce, gather and redistribute information from everyday activities (via Elvin) and to give that information a perceptible form (via the various clients) that can be publicly available and accessible as a resource for awareness. The integration of lightweight chat facilities with these information sources enables awareness to easily flow into interaction, starting to re-connect bodies to actions, and starting to approximate the easy flow of interaction that happens when we are co-located. Technically, the conceptual simplicity of the Elvin notification, the wide availability of its APIs, and the generic functionality of its clients, especially Tickertape, have made the use of the service appealing to developers and users for a wide range of uses
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