Statistical Assertions for Validating Patterns and Finding Bugs in Quantum Programs

In support of the growing interest in quantum computing experimentation, programmers need new tools to write quantum algorithms as program code. Compared to debugging classical programs, debugging quantum programs is difficult because programmers have limited ability to probe the internal states of quantum programs; those states are difficult to interpret even when observations exist; and programmers do not yet have guidelines for what to check for when building quantum programs. In this work, we present quantum program assertions based on statistical tests on classical observations. These allow programmers to decide if a quantum program state matches its expected value in one of classical, superposition, or entangled types of states. We extend an existing quantum programming language with the ability to specify quantum assertions, which our tool then checks in a quantum program simulator. We use these assertions to debug three benchmark quantum programs in factoring, search, and chemistry. We share what types of bugs are possible, and lay out a strategy for using quantum programming patterns to place assertions and prevent bugs.Comment: In The 46th Annual International Symposium on Computer Architecture (ISCA '19). arXiv admin note: text overlap with arXiv:1811.0544

Infrastrukturloser Fußgängerpositionierung

Many methods for pedestrian positioning exist. In outdoor environments, global satellite navigation systems such as GPS can give satisfactory positioning performance in many circumstances encountered by pedestrians. Pre-installed outdoor communication infrastructure, such as cellular networks or TV broadcast signals, can be leveraged for pedestrian uses. Specialized RF, ultrasound or light ranging beacons can also be installed indoors for positioning in spaces as small as individual rooms and networks of transponders can cover large installations. However, all these systems use transmitted signals that are subject to attenuation, blocking, reflection and diffraction effects, all of which can greatly reduce the accuracy and availability of range information. In contrast, Inertial Navigation Systems (INS) are "sourceless" in that they do not rely on any external transmitted signals. This explains their great utility in highend land, air, marine and space guidance, navigation and control systems, where dependingon external signals for aiding purposes might be impractical or risky. Unfortunately, for pedestrian navigation, unaided traditional INSs are of limited use. If the upper limit to the position error is set to some reasonable value, say a few metres after some 10s of minutes of self-contained navigation, either a very accurate navigation-grade INS or very frequent zero velocity updates (ZUPTs) with a tactical grade system are required. These realities, plus the fact that navigation-grade INSs will remain large, costly and power-hungry for at least another 10 years, means that traditional mechanization schemes for self-contained, personal navigation are currently impractical. The overall objective of this thesis is to investigate how low-grade, low-cost, and low-power INSs can be exploited for pedestrian positioning and in particular for first responder scenarios. To begin, a thorough bibliography of past research permits the identification of the relative merits of various technologies that have been proposed for emergency, rescue and military operations. Next, an extension to the well-studied occurrential pedestrian dead reckoning (PDR) technique using headgear-mounted motion sensors is described and good distance over ground (DoG) estimation performance is demonstrated. Since it is not a simple matter to apply occurrential techniques to a large class of locomotion patterns, the foot-inertial technique is then explored as an alternative. With an IMU (Inertial Measurement Unit) attached to (and in the future, mounted in) footwear, simplified strapdown inertial navigation techniques allow for omnidirectional motion patterns, very good DoG estimates, and vertical excursion characterization. Unfortunately, large heading jumps occur indoors, caused by magnetic disturbances and by the use of a generic orientation filter. It is shown how these heading errors can be modeled and then mitigated via map filtering techniques running over minimal a priori building geometry information

Infrastructureless Pedestrian Positioning

Many methods for pedestrian positioning exist. In outdoor environments, global satellite navigation systems such as GPS can give satisfactory positioning performance in many circumstances encountered by pedestrians. Pre-installed outdoor communication infrastructure, such as cellular networks or TV broadcast signals, can be leveraged for pedestrian uses. Specialized RF, ultrasound or light ranging beacons can also be installed indoors for positioning in spaces as small as individual rooms and networks of transponders can cover large installations. However, all these systems use transmitted signals that are subject to attenuation, blocking, reflection and diffraction effects, all of which can greatly reduce the accuracy and availability of range information. In contrast, Inertial Navigation Systems (INS) are sourceless in that they do not rely on any external transmitted signals. This explains their great utility in highend land, air, marine and space guidance, navigation and control systems, where dependingon external signals for aiding purposes might be impractical or risky. Unfortunately, for pedestrian navigation, unaided traditional INSs are of limited use. If the upper limit to the position error is set to some reasonable value, say a few metres after some 10s of minutes of self-contained navigation, either a very accurate navigation-grade INS or very frequent zero velocity updates (ZUPTs) with a tactical grade system are required. These realities, plus the fact that navigation-grade INSs will remain large, costly and power-hungry for at least another 10 years, means that traditional mechanization schemes for self-contained, personal navigation are currently impractical. The overall objective of this thesis is to investigate how low-grade, low-cost, and low-power INSs can be exploited for pedestrian positioning and in particular for first responder scenarios. To begin, a thorough bibliography of past research permits the identification of the relative merits of various technologies that have been proposed for emergency, rescue and military operations. Next, an extension to the well-studied occurrential pedestrian dead reckoning (PDR) technique using headgear-mounted motion sensors is described and good distance over ground (DoG) estimation performance is demonstrated. Since it is not a simple matter to apply occurrential techniques to a large class of locomotion patterns, the foot-inertial technique is then explored as an alternative. With an IMU (Inertial Measurement Unit) attached to (and in the future, mounted in) footwear, simplified strapdown inertial navigation techniques allow for omnidirectional motion patterns, very good DoG estimates, and vertical excursion characterization. Unfortunately, large heading jumps occur indoors, caused by magnetic disturbances and by the use of a generic orientation filter. It is shown how these heading errors can be modeled and then mitigated via map filtering techniques running over minimal a priori building geometry information

Effectiveness and Safety of Vedolizumab Induction Therapy for Patients with Inflammatory Bowel Disease

International audienceBackground & aims - Phase 3 trials have shown the efficacy of vedolizumab, which binds to integrin α4β7, in patients with Crohn's disease (CD) or ulcerative colitis (UC). We investigated the effectiveness and safety of vedolizumab in patients who failed anti-tumor necrosis factor therapy. Methods - From June through December 2014, there were 173 patients with CD and 121 patients with UC who were included in a multicenter nominative compassionate early access program granted by French regulatory agencies. This program provided patients with access to vedolizumab before it was authorized for marketing. Vedolizumab (300 mg) was administered intravenously at weeks 0, 2, and 6, and then every 8 weeks. Disease activity was assessed using the Harvey-Bradshaw Index for CD and the partial Mayo Clinic score for UC. We report results obtained after the 14-week induction phase. Results - Among the 294 patients treated with vedolizumab (mean age, 39.5 ± 14.0 y; mean disease duration, 10.8 ± 7.6 y; concomitant steroids, 44% of cases), 276 completed the induction period, however, 18 discontinued vedolizumab because of a lack of response (n = 14), infusion-related reaction (n = 2), or infections (n = 2). At week 14, 31% of patients with CD were in steroid-free clinical remission and 51% had a response; among patients with UC, 36% were in steroid-free clinical remission and 50% had a response. No deaths were reported. Severe adverse events occurred in 24 patients (8.2%), including 15 (5.1%) that led to vedolizumab discontinuation (1 case of pulmonary tuberculosis and 1 rectal adenocarcinoma). Conclusions - In a cohort of patients with CD or UC who failed previous anti-tumor necrosis factor therapy, approximately one third of patients achieved steroid-free clinical remission after 14 weeks of induction therapy with vedolizumab. This agent had an acceptable safety profile in these patients

A clinical decision support tool may help to optimise vedolizumab therapy in Crohn's disease

International audienceBackground A clinical decision support tool (CDST) has been validated for predicting treatment effectiveness of vedolizumab (VDZ) in Crohn's disease. Aim To assess the utility of this CDST for predicting exposure-efficacy and disease outcomes. Methods Using data from three independent datasets (GEMINI, GETAID and VICTORY), we assessed clinical remission rates and measured VDZ exposure, rapidity of onset of action, response to dose optimisation and progression to surgery by CDST-defined response groups (low, intermediate and high). Results A linear relationship existed between CDST-defined groups, measured VDZ exposure, rapidity of onset of action and efficacy in GEMINI through week 52 (P < 0.001 at all time points across three CDST-defined groups). In GETAID, CDST predicted differences in clinical remission at week 14 (AUC = 0.68) and rapidity of onset of action (P = 0.04) between probability groups. The high-probability patients did not benefit from shortening of infusion intervals, and differences in onset of action between the high-intermediate and low-probability groups within GETAID were no longer significant when including low-probability patients who received a week 10 infusion. CDST predicted a twofold increase in surgery risk over 12 months of VDZ therapy among low- to intermediate-probability vs high-probability patients (adjusted HR 2.06, 95% CI 1.33-3.21). Conclusions We further extended the clinical utility of a previously validated VDZ CDST, which accurately predicts at baseline exposure-efficacy relationships and rapidity of onset of action and could be used to help identify patients who would most benefit from interval shortening and those most likely to require surgery while on active therapy