Carotid paragangliomas: case report and imaging review

Background: Presentation of case reviews depicting the imaging characteristics of carotid paragangliomas, associated with a thorough analysis of the anatomical morphological features and the current therapeutic strategies.Materials and methods: We present the cases of 3 patients diagnosed with carotid paragangliomas in our clinic, illustrating diagnostic imaging elements by computer tomography (CT) and magnetic resonance imaging (MRI), but also the postoperative aspect of the carotid system, with respective anatomical, clinical and surgical considerations.Results: The imaging aspect of the carotid paragangliomas is characterised by a mass of soft tissue with intense contrast enhancement and with “salt and pepper” MRI appearance on conventional spin-echo sequences. The postoperative evolution of the patients included in the article was favourable, without any perioperative complications or signs of local tumour recurrence.Conclusions: Carotid paragangliomas are rare, often asymptomatic tumours, but with potential for increased malignancy, which raises the need for good knowledge of the cervical region pathology as well as the features of neuroendocrine tumours. CT and MRI examinations are essential for diagnosis, staging and, implicitly, for establishing the therapeutic strategy

On enhancing the robustness of commercial operating systems

A ubiquitous computing system derives its operations from the collective interactions of its constituent components. Consequently, a robust ubiquitous system entails that the discrete components must be robust to handle errors arising in themselves and over interactions with other system components. This paper conceptually outlines a profiling framework that assists in finding weaknesses in one of the fundamental building blocks of computer based systems, namely the Operating System (OS). The framework allows a system designer to ascertain possible error propagation paths, from drivers through the OS to applications. This significantly helps enhance the OS (or driver/application) with selective robustness hardening capabilities, i.e., robustness wrappers. © Springer-Verlag Berlin Heidelberg 2005

Profiling the operational behavior of OS device drivers

As the complexity of modern Operating Systems (OS) increases, testing key OS components such as device drivers (DD) becomes increasingly complex given the multitude of possible DD interactions. Currently, DD testing entails a broad spectrum of techniques, where static (requiring source code) and dynamic (requiring the executable image) and static-dynamic testing combinations are employed. Despite the sustained and improving test efforts in the field of driver development, DDs still represent a significant cause of system outages as the coverage is invariably limited by test resources and release time considerations. The basic factor is the inability to exhaustively assess and then cover the operational states, leading to releases of inadequately tested DDs. Consequently, if representative operational activity profiles of DDs within an OS could be obtained, these could significantly improve the understanding of the actual operational DD state space and help focus the test efforts. Focusing on characterizing DD operational activities while assuming no access to source code, this paper proposes a quantitative technique for profiling the runtime behavior of DDs using a set of occurrence and temporal metrics obtained via I/O traffic characterization. Such profiles are used to improve test adequacy against real-world workloads by enabling similarity quantification across them. The profiles also reveal execution hotspots in terms of DD functionalities activated in the field, thus allowing for dedicated test campaigns.A case study on actual Windows XP and Vista drivers using various performance and stability benchmarks as workloads substantiates our proposed approach. © Springer Science + Business Media, LLC 2009

Improving robustness testing of COTS OS extensions

Operating systems (OS) are increasingly geared towards support of diverse peripheral components, both hardware (HW) and software (SW), rather than explicitly focused on increased reliability of delivered OS services. The interface between the OS and the HW devices is provided by device drivers. Furthermore, drivers have become add-on COTS components to support the OS's capabilities of widespread device support. Unfortunately, drivers constitute a major cause of system outages, impacting overall service reliability. Consequently, the testing of drivers becomes important. However, despite the efforts to develop appropriate testing methods, the multitude of possible system configurations and lack of detailed OS specifications makes the task difficult. Not requiring access to OS source code, this paper develops novel, non-intrusive support for test methods, based on ascertaining test progress from a driver's operational state model. This approach complements existing schemes, enhancing the level of accuracy of the test process by providing test location guidance. © Springer-Verlag Berlin Heidelberg 2006