This paper deals with testing distributed software systems. In the past, two important problems have been determined for executing tests using a distributed test architecture: controllability and observability problems. A coordinated test method has subsequently been proposed to solve these two problems. In the present article: 1) we show that controllability and observability are indeed resolved if and only if the test system respects some timing constraints, even when the system under test is non-real-time; 2) we determine these timing constraints; 3) we determine other timing constraints which optimize the duration of test execution; 4) we show that the communication medium used by the test system has not to be necessarily FIFO; and 5) we show that the centralized test method can be considered just as a particular case of the proposed coordinated test method.

No abstract

No abstract

No abstract

With the advent of visual sensor networks (VSNs), energy-aware compression algorithms have gained wide attention. That is, new strategies and mechanisms for power-efficient image compression algorithms are developed, since the application of the conventional methods is not always energy beneficial. In this paper, we provide a survey of image compression algorithms for visual sensor networks, ranging from the conventional standards such as JPEG and JPEG2000 to a new compression method, for example, compressive sensing. We provide the advantages and shortcomings of the application of these algorithms in VSN, a literature review of their application in VSN, as well as an open research issue for each compression standard/method. Moreover, factors influencing the design of compression algorithms in the context of VSN are presented. We conclude by some guidelines which concern the design of a compression method for VSN.