Towards Predicated WCET Analysis

In this paper, we propose the use of constraint logic programming as a way of modeling context-sensitive execution-times of program segments. The context-sensitive constraints are collected automatically through static analysis or measurements. We achieve considerable tightness in comparison to traditional calculation methods that exceeded 20% in some cases during evaluation. The use of constraint-logic programming in our calculations proves to be the right choice when compared to the exponential behaviour recorded by the use of integer linear-programming

When the worst-case execution time estimation gains from the application semantics

International audienceCritical embedded systems are generally composed of repetitive tasks that must meet drastic timing constraints, such as termination deadlines. Providing an upper bound of the worst-case execution time (WCET) of such tasks at design time is thus necessary to prove the correctness of the system. Static timing analysis methods compute safe WCET upper bounds, but at the cost of a potentially large over-approximation. Over-approximation may come from the fact that WCET analysis may consider as potential worst-cases some executions that are actually infeasible, because of the semantics of the program and/or because they correspond to unrealistic inputs. In this paper, we introduce a complete semantic-aware WCET estimation workflow. We introduce some program analysis to find infeasible paths: they can be performed at design, C or binary level, and may take into account information provided by the user. We design an annotation-aware compilation process that enables to trace the infeasible path properties through the program transformations performed by the compilers. Finally, we adapt the WCET estimation tool to take into account the kind of annotations produced by the workflow

Improving the WCET computation time by IPET using control flow graph partitioning

Implicit Path Enumeration Technique (IPET) is currently largely used to compute Worst Case Execution Time (WCET) by modeling control flow and architecture using integer linear programming (ILP). As precise architecture effects requires a lot of constraints, the super-linear complexity of the ILP solver makes computation times bigger and bigger. In this paper, we propose to split the control flow of the program into smaller parts where a local WCET can be computed faster - as the resulting ILP system is smaller - and to combine these local results to get the overall WCET without loss of precision. The experimentation in our tool OTAWA with lp_solve solver has shown an average computation improvement of 6.5 times

An integrated project evaluation tool for public-private partnership projects

The evaluation of a large infrastructure project is a critical activity for bidders and governments under traditional procurement or through Public Private Partnership. When a project requires huge capital investment, public-private partnership (PPP) is often sought as an alternative in cases of shortage of public funds. Nevertheless, the complexity of the PPP arrangement has constituted a dilemma for government authorities to balance the interests between the public and the private parties (stakeholders). High capital burdens in terms of PPP bidding cost, construction cost, and operation and maintenance cost are part of the major challenges for private sponsors to get involved in PPP projects. Meanwhile, PPP scheme projects, believed to deliver better value for money, have been criticised by many as the product of highest influence level from either political patronage or corporate political power. There is an apparent need for a tool to help the government agency evaluate the delivery of value for money on PPP projects while still sustaining the interests of private parties. The aim of this research is to assist government agencies in evaluating bids and making decision efficiently for PPP seaport development projects through the use of an integrated project evaluation tool (IPET). A computer (MS excel program) based tool was developed to evaluate the project financial viability and negotiate the risk sharing mechanism of PPP Seaport Project at five different project stages. The stakeholders’ expectations, financial indicators, financial risks, and mitigation measures are considered and developed into the following modules: (1) Financial viability module; (2) Financial risk analysis module; and (3) Financial risk mitigation module. A triangulation strategy was justified with caution due to the possibility of error. A qualitative method (i.e. literature review and interview to explore stakeholders’ expectation and preferred indicators of PPP financial models) was undertaken prior to performing a quantitative technique (i.e. questionnaire survey to narrow down the preliminary findings). Then, the proposed tool was validated by comparing the results with secondary data and interviewing experts regarding their opinion on its applicability. The findings from the statistical analysis indicate that an efficient negotiation is possible if: (1) PPP financial models were used at the pre-proposal stage to examine the project’s ability in generating enough cash flow; (2) All stakeholders know the most important expectations and the most preferred financial indicators of other stakeholders; and (3) IRR, NPV, Revenue, Operating Cost, and Principal Payback are not considered as the only financial indicators for evaluating PPP projects. By knowing the mutual agreement among stakeholders, any conflicting expectations can also be identified early and it may be possible to accommodate such expectations in the negotiation process. The IPET has been confirmed that it has several implications: (1) possibility to facilitate an efficient negotiation and effective evaluation process; (2) applicability in evaluating PPP seaport projects; and (3) potentially to be extended to other sectors. However, the IPET is designed to be used with financial model, hence it will require an actual PPP financial model

Role of Imaging in the Staging and Response Assessment of Lymphoma:Consensus of the International Conference on Malignant Lymphomas Imaging Working Group

This article comprises the consensus reached to update guidance on the use of PET-CT for staging and response assessment for 18F FDG-avid lymphomas in clinical practice and late-phase trials

The WCET Tool Challenge 2011

Following the successful WCET Tool Challenges in 2006 and 2008, the third event in this series was organized in 2011, again with support from the ARTIST DESIGN Network of Excellence. Following the practice established in the previous Challenges, the WCET Tool Challenge 2011 (WCC'11) defined two kinds of problems to be solved by the Challenge participants with their tools, WCET problems, which ask for bounds on the execution time, and flow-analysis problems, which ask for bounds on the number of times certain parts of the code can be executed. The benchmarks to be used in WCC'11 were debie1, PapaBench, and an industrial-strength application from the automotive domain provided by Daimler AG. Two default execution platforms were suggested to the participants, the ARM7 as "simple target'' and the MPC5553/5554 as a "complex target,'' but participants were free to use other platforms as well. Ten tools participated in WCC'11: aiT, Astr\'ee, Bound-T, FORTAS, METAMOC, OTAWA, SWEET, TimeWeaver, TuBound and WCA

PRECISE YET SCALABLE RESOURCE ANALYSIS VIA SYMBOLIC EXECUTION

Ph.DDOCTOR OF PHILOSOPH

Post-ABVD/pre-radiotherapy 18F-FDG-PET provides additional prognostic information for early-stage Hodgkin lymphoma: A retrospective analysis on 165 patients

OBJECTIVE: To evaluate the prognostic role of both interim fluorine-18 fludeoxyglucose positron emission tomography (i-(18)F-FDG-PET) and end-of-chemotherapy fluorine-18 fludeoxyglucose positron emission tomography (eoc-(18)F-FDG-PET) in patients with early-stage Hodgkin lymphoma (HL). METHODS: We screened 257 patients with early-stage HL treated with combined modality therapy between March 2003 and July 2011. All were staged using fluorine-18 fludeoxyglucose positron emission tomography ((18)F-FDG-PET) before chemotherapy and after two doxorubicin, bleomycin, vinblastine and dacarbazine cycles (i-(18)F-FDG-PET); 165 patients were also evaluated by (18)F-FDG-PET at the end of chemotherapy (eoc-(18)F-FDG-PET). RESULTS: After revision, 85% of patients were negative for i-(18)F-FDG-PET and 15% were positive. After eoc-(18)F-FDG-PET revision, 23 patients had a positive scan. The median follow-up was 56 months. The 5-year overall survival (OS) and progression-free survival (PFS) for the whole cohort were 97.5% and 95.6%, respectively. For i-(18)F-FDG-PET-negative and i-(18)F-FDG-PET-positive patients, the 5-year PFS rates were 98% and 84%, respectively; for eoc-(18)F-FDG-PET-negative and eoc-(18)F-FDG-PET-positive patients, the 5-year PFS rates were 97% and 78%, respectively. Combining the i-(18)F-FDG-PET and eoc-(18)F-FDG-PET results, the 5-year PFS were 97%, 100% and 82% in negative/negative, positive/negative and positive/positive groups, respectively. The 5-year OS rates were 98% and 83% in eoc-(18)F-FDG-PET-negative and eoc-(18)F-FDG-PET-positive patients, respectively; the 5-year OS was 98%, 100% and 83% in negative/negative, positive/negative and positive/positive groups, respectively. CONCLUSION: This study provides additional information on the prognostic role of i-(18)F-FDG-PET and eoc-(18)F-FDG-PET in early-stage HL. As data are accumulating and the clinical scenario is rapidly evolving, we might need to rethink the use of (18)F-FDG-PET as a prognostic marker for early-stage HL in the near future. ADVANCES IN KNOWLEDGE: This study provides additional information on the prognostic role of i-(18)F-FDG-PET and eoc-(18)F-FDG-PET in early-stage HL. On the basis of the present data, we may suggest to use eoc-(18)F-FDG-PET as a strong prognostic marker, especially for patients with i-(18)F-FDG-PET positivity