Prototyping the Semantics of a DSL using ASF+SDF: Link to Formal Verification of DSL Models

A formal definition of the semantics of a domain-specific language (DSL) is a key prerequisite for the verification of the correctness of models specified using such a DSL and of transformations applied to these models. For this reason, we implemented a prototype of the semantics of a DSL for the specification of systems consisting of concurrent, communicating objects. Using this prototype, models specified in the DSL can be transformed to labeled transition systems (LTS). This approach of transforming models to LTSs allows us to apply existing tools for visualization and verification to models with little or no further effort. The prototype is implemented using the ASF+SDF Meta-Environment, an IDE for the algebraic specification language ASF+SDF, which offers efficient execution of the transformation as well as the ability to read models and produce LTSs without any additional pre or post processing.Comment: In Proceedings AMMSE 2011, arXiv:1106.596

Rate, characteristics, and factors associated with high emergency department utilization

Background: Patients with high emergency department (ED) utilization account for a disproportionate number of ED visits. The existing research on high ED utilization has raised doubts about the homogeneity of the frequent ED user. Attention to differences among the subgroups of frequent visitors (FV) and highly frequent visitors (HFV) is necessary in order to plan more effective interventions. In the Netherlands, the incidence of high ED utilization is unknown. The purpose of this study was to investigate if the well-documented international high ED utilization also exists in the Netherlands and if so, to characterize these patients. Therefore, we assessed the proportion of FV and HFV; compared age, sex, and visit outcomes between patients with high ED utilization and patients with single ED visits; and explored the factors associated with high ED utilization. Methods: A 1-year retrospective descriptive correlational study was performed in two Dutch EDs, using thresholds of 7 to 17 visits for frequent ED use, and greater than or equal to 18 visits for highly frequent ED use. Results: FV and HFV (together accounting for 0.5% of total ED patients) attended the ED 2,338 times (3.3% of the total number of ED visits). FV and HFV were equally likely to be male or female, were less likely to be self-referred, and they suffered from urgent complaints more often compared to patients with single visits. FV were significantly older than patients with single visits and more often admitted than patients with single visits. Several chief complaints were indicative for frequent and highly frequent ED use, such as shortness of breath and a psychiatric disorder. Conclusions: Based on this study, high ED utilization in the Netherlands seems to be less a problem than outlined in international literature. No major differences were found between FV and HFV, they presented with the same, often serious, problems. Our study supports the notion that most patients with high ED utilization visit the ED for significant medical problems. © 2014 van der Linden et al.; licensee Springer

Angiographic findings in patients with refractory unstable angina according to troponin T status

BACKGROUND: The CAPTURE (C7E3 fab AntiPlatelet Therapy in Unstable REfactory angina) trial enrolled patients with refractory unstable angina and documented a therapeutic benefit for abciximab, a platelet glycoprotein IIb/IIIa receptor antagonist, that was particularly evident in patients with elevated troponin T (TnT) levels. In the current study, we related the angiographic data to the TnT status of the CAPTURE patients. METHODS AND RESULTS: In 853 patients, angiographic data at baseline and 18 to 24 hours after treatment were available and assessed by an Angiographic Committee with respect to TIMI flow, lesion severity, and visibility of thrombus. TnT levels >0.1 microg/L were found in 30.9% of the patients. Before randomization, thrombus was visible in 14.6% of TnT-positive patients (TnT levels >0.1 microg/L) and 4.2% of TnT-negative patients (P=0.004). Complex lesion characteristics B2+/C (72.0% versus 53.9%; P<0.001) and TIMI flow <2 (15.6% versus 5. 1%; P<0.001) were more frequent in TnT-positive patients. Abciximab was effective with respect to reduction of visible thrombus, increase of TIMI flow, and reduction of cardiac events in TnT-positive patients only. Multivariate analysis identified TnT status, but not angiographic findings, as an independent predictor for both outcome and efficacy of treatment with abciximab. CONCLUSIONS: Complex lesion characteristics and visible thrombus formation at baseline were significantly linked to TnT elevation. However, TnT st

The NEtherlands Cervical Kinematics (NECK) Trial. Cost-effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in the treatment of cervical disc herniation; a double-blind randomised multicenter study

Background. Patients with cervical radicular syndrome due to disc herniation refractory to conservative treatment are offered surgical treatment. Anterior cervical discectomy is the standard procedure, often in combination with interbody fusion. Accelerated adjacent disc degeneration is a known entity on the long term. Recently, cervical disc prostheses are developed to maintain motion and possibly reduce the incidence of adjacent disc degeneration. A comparative cost-effectiveness study focused on adjacent segment degeneration and functional outcome has not been performed yet. We present the design of the NECK trial, a randomised study on cost-effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in patients with cervical disc herniation. Methods/Design. Patients (age 18-65 years) presenting with radicular signs due to single level cervical disc herniation lasting more than 8 weeks are included. Patients will be randomised into 3 groups: anterior discectomy only, anterior discectomy with interbody fusion, and anterior discectomy with disc prosthesis. The primary outcome measure is symptomatic adjacent disc degeneration at 2 and 5 years after surgery. Other outcome parameters will be the Neck Disability Index, perceived recovery, arm and neck pain, complications, re-operations, quality of life, job satisfaction, anxiety and depression assessment, medical consumption, absenteeism, and costs. The study is a randomised prospective multicenter trial, in which 3 surgical techniques are compared in a parallel group design. Patients and research nurses will be kept blinded of the allocated treatment for 2 years. The follow-up period is 5 years. Discussion. Currently, anterior cervical discectomy with fusion is the golden standard in the surgical treatment of cervical disc herniation. Whether additional interbody fusion or disc prothesis is necessary and cost-effective will be determined by this trial. Trial Registration. Netherlands Trial Register NTR1289

Towards verified Java code generation from concurrent state machines

We present work in progress on, verified, transformation of a modeling language based on communicating concurrent state machines, SLCO, to Java. Some concurrency related challenges, related to atomicity and non-standard fairness issues, are pointed out. We discuss solutions based on Java synchronization concepts

Effect of a workplace-based group training programme combined with financial incentives on smoking cessation:a cluster-randomised controlled trial

Prevention, Population and Disease management (PrePoD)Public Health and primary car