Improved eventing protocol for universal plug and play

UPnP is a widely-spread connectivity standard, which allows networked devices to cooperate in an autonomous fashion by using functionality found on the network. In this article we validate UPnP as a service-oriented architecture. We identify shortcomings of the standard and propose solutions. In our view, eventing is the weakest mechanism in UPnP technology. We propose extensions to the existing eventing protocol in UPnP, which allow overcoming identified problems. We compare our solution with standard UPnP with respect to performance

A first step towards a dependability framework for smart environment applications

Smart environments will consist of a large number of heterogeneous devices that communicate to collaboratively perform various tasks for users. We propose a novel dependability framework to increase availability and reliability of smart environment applications. We argue that the key step in achieving high dependability is to predict faults before they occur. Many statistical fault prediction techniques have been proposed for smart environment applications. Selecting the best one among these techniques involves performance assessment and detailed comparison on given metrics. We present a linear regression-based prediction model to predict the remaining battery lifetime of a device to prevent faults due to low battery. Further, we discuss the proposed dependability framework, the basic approaches and the corresponding mechanisms to achieve our long-term research goal. We envision that dependability framework will reduce maintenance costs of large-scale smart environments and increase the dependability of smart environment applications

Worst-case response time analysis of real-time tasks under fixed-priority scheduling with deferred preemption revisited

Fixed-priority scheduling with deferred preemption (FPDS) has been proposed in the literature as a viable alternative to fixed-priority preemptive scheduling (FPPS), that both reduces the cost of arbitrary preemptions and removes the need for non-trivial resource access protocols. This paper shows that existing worst-case response time analysis of hard real-time tasks under FPDS, arbitrary phasing and relative deadlines at most equal to periods is both pessimistic and optimistic. This paper provides a revised analysis, resolving the problems with the existing approaches. The analysis assumes a continuous scheduling model. It is shown that the critical instant, longest busy period, and worst-case response time for a task are suprema rather than maxima for all tasks, except for the lowest priority task. Moreover, it is shown that the analysis is not uniform for all tasks, i.e. the analysis for the lowest priority task differs from the analysis of the other tasks, because only the lowest priority task cannot be blocked. To build on earlier work, the worst-case response time analysis for FPDS is expressed in terms of known worst-case analysis results for FPPS. The paper includes pessimistic variants of the analysis, which are uniform for all tasks

Performance and fairness in VANETs

This paper presents performance and fairness analysis of the 802.11p Medium Access Control (MAC) in one-hop periodic broadcast V2V communication used in cooperative driving applications aimed for improving vehicle safety and traffic efficiency. We show that both performance and fairness strongly dependent on the random relative phasing (F0) of the vehicles and on the impact of Hidden Nodes (HNs)

Grasp : visualizing the behavior of hierarchical multiprocessor real-time systems

Trace visualization is a viable approach for gaining insight into the behavior of complex distributed real-time systems. Grasp is a versatile trace visualization toolset. This paper presents its unique visualization capabilities for hierarchical multiprocessor systems, including partitioned and global multiprocessor scheduling with migrating tasks and jobs, communication between jobs via shared memory and message passing, and hierarchical scheduling in combination with multiprocessor scheduling. Its flexible plugin infrastructure allows for easy extension with custom visualization and analysis techniques for automatic trace verification. Grasp is freely available on the web

In-plane user positioning indoors

Indoor positioning is a service required by many smart environment applications for various purposes, such as activity classification, indoor navigation and context awareness. In this paper, we present a novel approach to the user positioning problem based on in-plane detection enabled by a set of infrared light emitters and sensors placed horizontally along the walls. The simulation results show that the proposed system is able to determine locations of multiple users inside the room with high precision and accuracy

System architecture for road lighting

Traditional road lighting systems consume a large amount of energy. When the ambient light falls under a certain threshold, all the luminaries are turned at full-power without considering user perception and interaction. The feeling of safety experienced by users and user-lighting system interaction via consumer electronics (CE) devices should be investigated. For this study, we establish a software-controlled testbed that allows changing the brightness level of each street luminary remotely. In this paper, we describe the system architecture of this testbed deployed on a street along with the future work directions

Language-based access control approach for component-based software applications

Security in component-based software applications is studied by looking at information leakage from one component to another through operation calls. Components and security specifications about confidentiality as regular languages are modelled. Then a systematic way is provided to synthesise an access control mechanism, which not only guarantees all specifications to be obeyed, but also allows each user to attain maximum permissive behaviours