| 1. |
- Backlund, Björn, et al.
(author)
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A graphical G-LOTOS editor defined by meta-tool LOGGIE
- 1989. - 1
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Reports (other academic/artistic)abstract
- We present a prototype implementation of a graphical editor for a subset of G-LOTOS. The graphical G-LOTOS syntax is beeing standardized within ISO for the LOTOS specification language. First, we provide a formal definition of the G-LOTOS subset. Then, the specification the editor is derived from this formal definition. Finally, the editor is generated automatically using the LOGGIE meta-tool.
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| 2. |
- Backlund, Björn, et al.
(author)
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Generation of graphic language-oriented design environments
- 1989. - 1
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Reports (other academic/artistic)abstract
- We review some results in the area of using meta techniques to generate language-oriented programming environments. We focus on environments for languages having a two-dimensional syntax based on attribute grammars and constraints. We introduce edit-semantic attributes, a new classof attributes which control the user interaction and graphic presentation. We present LOGGIE, a prototype tool implementing some of the meta techniques discussed. The tool generates interactive language-oriented graphical editors.
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| 3. |
- Nungu, Amos, 1975-, et al.
(author)
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On Building Sustainable Broadband Networks in Rural Areas
- 2011
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In: 2011 Technical Symposium at ITU Telecom World (ITU WT11). - 9781457711480 ; , s. 135-140
-
Conference paper (peer-reviewed)abstract
- We present research on how to build sustainablebroadband networks in rural areas of developing regions. Due toan increasing political awareness of the importance of ICT fordevelopment, many such regions are now being networked. Thespecific design considerations are due to the technical and non-technical challenges found in those areas. Our research includesa pilot implementation in rural Tanzania.
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| 4. |
- Bagula, Antoine B
(author)
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Hybrid Routing in Next Generation IP Networks : QoS Routing Mechanisms and Network Control Strategies
- 2006
-
Doctoral thesis (other academic/artistic)abstract
- Communication networks have evolved from circuit-switched and hop-by-hop routed systems into hybrid data/optical networks using the Internet as a common backbone carrying narrow- and broad-band traffic offered by a multitude of access networks. This data/optical backbone is built around a multi-technology/multi-protocol routing architecture which runs the IP protocols in a collapsed IP stack where ATM and SONET/SDH have been replaced by the suite of Generalized Multiprotocol Label Switching (GMPLS) protocols. A further evolution referred to as ``IP over Photons'' or ``All IP - All Optical'' is expected where ``redundant intermediate layers'' will be eliminated to run IP directly on top of optical cross-connects (OXCs) with the expectation of achieving savings on operation expenditures (OPEX) and capital expenditures (CAPEX). ``IP over Photons'' has been stalled by the immaturity in the control and data plane technologies leading to complex and time-consuming manual network planning and configurations which require a group of ``layer experts'' to operate and maintain a hybrid data/optical network. By making the status of each link and node of a data/optical network visible to a common control, GMPLS protocols have opened the way for automated operation and management allowing the different layers of an IP stack to be managed by a single network operator. GMPLS protocols provide the potential to make more efficient use of the IP backbone by having network management techniques such as Traffic Engineering (TE) and Network Engineering (NE), once the preserve of telecommunications, to be reinvented and deployed to effect different Quality of Service (QoS) requirements in the IP networks. NE moves bandwidth to where the traffic is offered to the network while TE moves traffic to where the bandwidth is available to achieve QoS agreements between the current and expected traffic and the available resources. However,several issues need to be resolved before TE and NE be effectively deployed in emerging and next generation IP networks. These include (1) the identification of QoS requirements of the different network layer interfaces of the emerging and next generation IP stack (2) the mapping of these QoS requirements into QoS routing mechanisms and network control strategies and (3) the deployment of these mechanisms and strategies within and beyond an Internet domain's boundaries to maximize the engineering and economic efficiency. Building upon different frameworks and research fields, this thesis revisits the issue of Traffic and Network Engineering (TE and NE) to present and evaluate the performance of different QoS routing mechanisms and network control strategies when deployed at different network layer interfaces of a hybrid data/optical network where an IP over MPLS network is layered above an MP λS/Fiber infrastructure. These include mechanisms and strategies to be deployed at the IP/MPLS, MPLS/MP λS and MP λS/Fiber network layer interfaces. The main contributions of this thesis are threefold. First we propose and compare the performance of hybrid routing approaches to be deployed in IP/MPLS networks by combining connectionless routing mechanisms used by classical IGP protocols and the connection oriented routing approach borrowed from MPLS. Second, we present QoS routing mechanisms and network control strategies to be deployed at the MPLS/MP λS network layer interface with a focus on contention-aware routing and inter-layer visibility to improve multi-layer optimality and resilience. Finally, we build upon fiber transmission characteristics to propose QoS routing mechanisms where the routing in the MPLS and MP λS layers is conducted by Photonic characteristics of the fiber such as the availability of the physical link and its failure risk group probability.
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| 5. |
- Battiti, R., et al.
(author)
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Wireless LANs : From WarChalking to open access networks
- 2005
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In: Mobile Networks and Applications. - : Springer Science and Business Media LLC. - 1383-469X .- 1572-8153. ; 10:3, s. 275-287
-
Journal article (peer-reviewed)abstract
- This work discusses the evolution of W-LANs from their current status of wireless termination of LAN services to a possible global infrastructure where the access networks become open to multiple operators and a vehicle of a win-win scenario, where both users and operators benefit from the new network architecture. The idea of Open Access Networks (OANs) can go beyond wireless HotSpots and be generalized to a generic shared access infrastructure that fosters service operators competition and drastically reduces the cost of last mile coverage. The general concept of Open Access Networks is detailed, highlighting its difference with the more traditional model of vertical integration of the access network into the global service. About the OANs development, it is shown how to support the quick and smooth evolution of the infrastructure toward a widespread and reliable communication support. Business models are discussed by mentioning the different actors, the market organization and the different organization forms. The final part of the paper is devoted to technical challenges such as access control, security, privacy, roaming, resource exploitation and service differentiation. As an example of how to tackle these problems, we discuss a pricing technique devoted to resource management and billing support. In addition we present a simulation on how the OAN concept can speed-up the deployment of broadband access in a real case.
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| 6. |
- Byamukama, Maximus, et al.
(author)
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Design Guidelines for Ultra-low Power Gateways in Environment Monitoring Wireless Sensor Networks
- 2017
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In: 2017 IEEE AFRICON. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538627754 ; , s. 1472-1478
-
Conference paper (peer-reviewed)abstract
- We explore techniques that can be used to reduce the power consumption of gateways in wireless sensor networks deployed in environment monitoring applications, such as Automatic Weather Stations (AWS). The challenge is the deployment of these networks in locations that are far from a consistent power source, such as a national grid. Such stations must be autonomous and power consumption must be minimized. We present test scenarios illustrating the impact of the suggested techniques. We explore hardware and software based methods of power reduction, assess the impact of each, the constraints to be expected and how to overcome them. We then provide a reference implementation of a gateway in which we integrate these techniques. We show that power consumption can be reduced by 48 - 85% when comparing best and worst case scenarios. The reference implementation we provide consumes 27mW at 3V.
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| 7. |
- Byamukama, Maximus, et al.
(author)
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Energy Storage Options for Environment Monitoring Wireless Sensor Networks in Rural Africa
- 2018
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In: Proceedings - 2018 IEEE 12th International Conference on Compatibility, Power Electronics and Power Engineering, CPE-POWERENG 2018. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538625088
-
Conference paper (peer-reviewed)abstract
- This paper explores various traditional and emerging battery technologies available for deployments of automated environment monitoring devices using Wireless Sensor Networks (WSNs) in Africa and the considerations designers must take into account when implementing these systems. Environment-monitoring applications of WSNs are focusing more on reducing power consumption and optimizing data transmission and less on the constraints that their applications and deployment environments put on the energy storage device. We describe the various properties of energy storage devices and, for each, we highlight the requirements to be met for environment monitoring applications, especially in remote areas in Africa. We evaluate the performance of some of these energy storage options against the requirements using three use cases. We indicate the technologies that have shown reliability for each use case. We show that emerging battery technologies, such as Lithium Ion Capacitors are well suited for long-life low power deployments while the options for high-power deployments depend on the constraints faced by the designers, such as the power consumption of the sensor network components sand environment temperature range of the deployment environment.
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