K-branching UIO sequences for partially specified observable non-deterministic FSMs

In black-box testing, test sequences may be constructed from systems modelled as deterministic finite-state machines (DFSMs) or, more generally, observable non-deterministic finite state machines (ONFSMs). Test sequences usually contain state identification sequences, with unique input output sequences (UIOs) often being used with DFSMs. This paper extends the notion of UIOs to ONFSMs. One challenge is that, as a result of non-determinism, the application of an input sequence can lead to exponentially many expected output sequences. To address this scalability problem, we introduce K-UIOs: K-UIOs that lead to at most K output sequences from states of M. We show that checking K-UIO existence is PSPACE-Complete if the problem is suitably bounded; otherwise it is in EXPSPACE and PSPACE-Hard. We provide a massively parallel algorithm for constructing K-UIOs and the results of experiments on randomly generated and real FSM specifications. The proposed algorithm was able to construct UIOs in cases where the existing UIO generation algorithm could not and was able to construct UIOs from FSMs with 38K states and 400K transitions

Accelerating finite state machine-based testing using reinforcement learning

Testing is a crucial phase in the development of complex systems, and this has led to interest in automated test generation techniques based on state-based models. Many approaches use models that are types of finite state machine (FSM). Corresponding test generation algorithms typically require that certain test components, such as reset sequences (RSs) and preset distinguishing sequences (PDSs), have been produced for the FSM specification. Unfortunately, the generation of RSs and PDSs is computationally expensive, and this affects the scalability of such FSM-based test generation algorithms. This paper addresses this scalability problem by introducing a reinforcement learning framework: the Q -Graph framework for MBT. We show how this framework can be used in the generation of RSs and PDSs and consider both (potentially partial) timed and untimed models. The proposed approach was evaluated using three types of FSMs: randomly generated FSMs, FSMs from a benchmark, and an FSM of an Engine Status Manager for a printer. In experiments, the proposed approach was much faster and used much less memory than the state-of-the-art methods in computing PDSs and RSs

Testing timed systems modeled by stream X-machines

Stream X-machines have been used to specify real systems where complex data structures. They are a variety of extended finite state machine where a shared memory is used to represent communications between the components of systems. In this paper we introduce an extension of the Stream X-machines formalism in order to specify systems that present temporal requirements. We add time in two different ways. First, we consider that (output) actions take time to be performed. Second, our formalism allows to specify timeouts. Timeouts represent the time a system can wait for the environment to react without changing its internal state. Since timeous affect the set of available actions of the system, a relation focusing on the functional behavior of systems, that is, the actions that they can perform, must explicitly take into account the possible timeouts. In this paper we also propose a formal testing methodology allowing to systematically test a system with respect to a specification. Finally, we introduce a test derivation algorithm. Given a specification, the derived test suite is sound and complete, that is, a system under test successfully passes the test suite if and only if this system conforms to the specification

Selenium and Lung Cancer: A Systematic Review and Meta Analysis

Selenium is a natural health product widely used in the treatment and prevention of lung cancers, but large chemoprevention trials have yielded conflicting results. We conducted a systematic review of selenium for lung cancers, and assessed potential interactions with conventional therapies.Two independent reviewers searched six databases from inception to March 2009 for evidence pertaining to the safety and efficacy of selenium for lung cancers. Pubmed and EMBASE were searched to October 2009 for evidence on interactions with chemo- or radiation-therapy. In the efficacy analysis there were nine reports of five RCTs and two biomarker-based studies, 29 reports of 26 observational studies, and 41 preclinical studies. Fifteen human studies, one case report, and 36 preclinical studies were included in the interactions analysis. Based on available evidence, there appears to be a different chemopreventive effect dependent on baseline selenium status, such that selenium supplementation may reduce risk of lung cancers in populations with lower baseline selenium status (serum<106 ng/mL), but increase risk of lung cancers in those with higher selenium (≥ 121.6 ng/mL). Pooling data from two trials yielded no impact to odds of lung cancer, OR 0.93 (95% confidence interval 0.61-1.43); other cancers that were the primary endpoints of these trials, OR 1.51 (95%CI 0.70-3.24); and all-cause-death, OR 0.93 (95%CI 0.79-1.10). In the treatment of lung cancers, selenium may reduce cisplatin-induced nephrotoxicity and side effects associated with radiation therapy.Selenium may be effective for lung cancer prevention among individuals with lower selenium status, but at present should not be used as a general strategy for lung cancer prevention. Although promising, more evidence on the ability of selenium to reduce cisplatin and radiation therapy toxicity is required to ensure that therapeutic efficacy is maintained before any broad clinical recommendations can be made in this context

Capecitabine in combination with docetaxel and mitomycin C in patients with pre-treated tumours: results of an extended phase-I trial

Preclinical data suggest that the anti-tumour activity of capecitabine is enhanced by taxanes and mitomycin C through up-regulation of thymidine phosphorylase (TP). Here, we studied safety and efficacy of the combination of capecitabine with docetaxel and mitomycin C. Two dose levels (DL) were investigated: capecitabine 1000 mg m−2 b.i.d. on days 1–14, docetaxel 40 mg m−2 i.v. day 1, mitomycin C 4 or 6 mg m−2 i.v. day 1 (DL I or II). Cycles were repeated every 3 weeks. The primary aim was to determine the dose-limiting toxicities (DLT) during the first two treatment cycles and the maximum tolerated dose (MTD). A total of 46 patients (pts) refractory to standard therapies were enrolled, of whom the majority had gastrointestinal tumours (n=40). 14 pts had received ⩾3 lines of prior chemotherapy. At DL I, one out of six pts experienced DLT. At DL II, two out of six pts had DLT (mucositis grade 3). Thus, DL I was determined as MTD. Among a total of 37 pts treated on DL I the following toxicities were observed during cycles 1 and 2 (number of patients with grade 1/2/3/4 toxicity; NCI-CTC v. 3.0): anaemia 10/8/3/0, leucocytopenia 4/11/1/2, thrombocytopenia 0/1/2/0, diarrhoea 8/1/2/0, stomatitis/mucositis 3/3/1/0, nausea/vomiting 10/2/0/0, and hand-foot skin reaction 5/1/1/0. Of 30 pts who received at least two treatment cycles nine achieved complete or partial remissions, six pts achieved minor remissions, and seven pts had stable disease (tumour control rate 73%). Of note, four out of 10 patients with pancreatic cancer had partial remissions. In conclusion, capecitabine can safely be combined with docetaxel (40 mg m−2) and mitomycin C (4 mg m−2). The established regimen was well tolerated and the preliminary efficacy data in this heavily pre-treated patients population appears to be promising

Epidemiology of Escherichia coli bacteraemia in England: results of an enhanced sentinel surveillance programme

Background: Escherichia coli causes over one third of the bacteraemia cases in England each year, and the incidence of these infections is increasing. Aim: To determine the underlying risk factors associated with E. coli bacteraemia. Methods: A three month enhanced sentinel surveillance study involving 35 National Health Service hospitals was undertaken in the winter of 2012/13 to collect risk factor information and further details on the underlying source of infection to augment data already collected by the English national surveillance programme. Antimicrobial susceptibility results for E. coli isolated from blood and urine were also collected. Findings: A total of 1,731 cases of E. coli bacteraemia were included. The urogenital tract was the most commonly reported source of infection (51.2% of cases) with prior treatment for a urinary tract infection being the largest independent effect associated with this infection source. Half of all patients had prior healthcare exposure in the month prior to the bacteraemia with antimicrobial therapy and urinary catheterisation being reported in one third and one fifth of these patients. Prior healthcare exposure was associated with a higher proportion of antibiotic non-susceptibility in the blood culture isolates (P=0.001). Conclusion: Analysis of risk factors suggests potential community and hospital-related interventions particularly better use of urinary catheters and improved antibiotic management of urinary tract infections. As part of the latter strategy, antibiotic resistance profiles need to be closely monitored to ensure treatment guidelines are up to date to limit inappropriate empiric therapy

Scholarly publishing depends on peer reviewers

The peer-review crisis is posing a risk to the scholarly peer-reviewed journal system. Journals have to ask many potential peer reviewers to obtain a minimum acceptable number of peers accepting reviewing a manuscript. Several solutions have been suggested to overcome this shortage. From reimbursing for the job, to eliminating pre- publication reviews, one cannot predict which is more dangerous for the future of scholarly publishing. And, why not acknowledging their contribution to the final version of the article published? PubMed created two categories of contributors: authors [AU] and collaborators [IR]. Why not a third category for the peer-reviewer