The development of hard real-time systems using a formal approach

Hard real-time systems are a class of computer control systems that must react to demands of their environment by providing `correct' and timely responses. Since these systems are increasingly being used in systems with safety implications, it is crucial that they are designed and developed to operate in a correct manner. This thesis is concerned with developing formal techniques that allow the specification, verification and design of hard real-time systems. Formal techniques for hard real-time systems must be capable of capturing the system's functional and performance requirements, and previous work has proposed a number of techniques which range from the mathematically intensive to those with some mathematical content. This thesis develops formal techniques that contain both an informal and a formal component because it is considered that the informality provides ease of understanding and the formality allows precise specification and verification. Specifically, the combination of Petri nets and temporal logic is considered for the specification and verification of hard real-time systems. Approaches that combine Petri nets and temporal logic by allowing a consistent translation between each formalism are examined. Previously, such techniques have been applied to the formal analysis of concurrent systems. This thesis adapts these techniques for use in the modelling, design and formal analysis of hard real-time systems. The techniques are applied to the problem of specifying a controller for a high-speed manufacturing system. It is shown that they can be used to prove liveness and safety properties, including qualitative aspects of system performance. The problem of verifying quantitative real-time properties is addressed by developing a further technique which combines the formalisms of timed Petri nets and real-time temporal logic. A unifying feature of these techniques is the common temporal description of the Petri net. A common problem with Petri net based techniques is the complexity problems associated with generating the reachability graph. This thesis addresses this problem by using concurrency sets to generate a partial reachability graph pertaining to a particular state. These sets also allows each state to be checked for the presence of inconsistencies and hazards. The problem of designing a controller for the high-speed manufacturing system is also considered. The approach adopted mvolves the use of a model-based controller: This type of controller uses the Petri net models developed, thus preservIng the properties already proven of the controller. It. also contains a model of the physical system which is synchronised to the real application to provide timely responses. The various way of forming the synchronization between these processes is considered and the resulting nets are analysed using concurrency sets

Comparative and Interactive Effects of Land-and Aquatic-Based Plyometric Training on Agility and Peak Speed of Elite Young Athletes of the: Sporting Environment

The purpose of the present study was to investigate the effects of a six-week land-and aquatic-based  plyometric  training on agility  and  peak  speed  of  elite young  athletes.24 male elite young athletes (with average and standard deviation age of 19.16 ± 1.30 year., height 1.715 ± 8.826 m, weight 59.45 ± 8.93 kg) were tested at the beginning of the season. All subjects, after having been informed about the objective and protocol of the study, gave their written consents and the study was approved by Institutional Ethics Committee of Faculty of Sports Medicine and Physiotherapy  and Directorate  of  Sports,  Guru Nanak  Dev  University,  Amritsar,  India. The  subjects  were  randomly assigned  into  three  groups: Land-based  plyometric  training  group (L; n  =  08), Aquatic-based plyometric  training  group(A;  n  =  08),  and  control  (C;  n  =  08). Land-and aquatic-based plyometrictraining groupwas subjected to 6-weeks plyometric training twice a week for 35 minutes a day.505 agility test was used to monitor  the  development  of  the  athlete's  speed  and  agility  whereas  peak  speed test was used to monitor the development of the athlete‘s ability to effectively and efficiently build  up  acceleration,  from  standing  blocks,  to  maximum  speed. It  is  concluded  that  the  use  of aquatic  and  land  training  program  is  not  only  to  break  the  monotony  of  training,  but  they  can  also improve  the  strength  of  athletes,  that  ultimately  leads  to  the  optimal  performance  in  the sports competition

Molecular characterisation of the pneumonia virus of mice glycoprotein genes

The molecular characterisation of the major glycoproteins of pneumonia virus of mice (PVM) was undertaken to identify the molecular basis for different pathogenicities for two strains of PVM. One is highly pathogenic and passaged entirely in mice (strain J3666) whilst the other is non-pathogenic and has been passaged entirely in tissue culture (strain 15). Characterisation of the fusion proteins of these two strains revealed little amino acid changes that may account for their pathogenicities. Of the 537 amino acid long fusion protein, only four amino acid changes were observed between the two strains. None of the changes were located within the region encoding the cleavage site of the F₀ polypeptide and the altered amino acids were distributed throughout the fusion protein. The amino acids changes were considered to be fairly conservative and may represent adaptation of the two strains to their different modes of passaging. However, the importance of these changes with regards to cleavage cannot be ruled out since one or more of these changes may be located within the 3-dimensional structure of the F₀ cleavage site. Nucleotide sequence analysis of the attachment (G) glycoproteins of these two strains of PVM showed only two amino acids changes within the extracellular domain of the protein. However, the G proteins of the two strain differed from each other in that the G protein of strain J3666 possessed a N-terminal extension compared to that of strain 15. This amino acid extension forms the cytoplasmic domain of the G protein in strain J3666 but appears to be lacking in that of strain 15. Furthermore, the G proteins of both strains of PVM were synthesised from the second, but not the same, initiation codon. In PVM strain J3666, the first available initiation codon coded for a short polypeptide of 12 amino acids whereas that of strain 15 coded for a short polypeptide of 33 amino acids. Expression of the G genes in vitro produced polypeptides which were approximately 3K larger than their predicted molecular weights. Synthesis of polypeptides due to internal initiation during translation were observed for the G gene of strain J3666. Expression of the G genes using recombinant vaccinia virus expressing the T7 RNA polymerase showed that the G proteins of both strains of PVM were expressed on the surface of cells transfected in vitro. Thus, the signals required for the correct processing and transport of the G proteins of PVM are not contained within the cytoplasmic domain of the proteins. The first steps of an investigation of possible ribosomal frameshifting event occurring within the G gene of PVM strain 15 was undertaken. The initiation codon of the major and short ORF's of the G gene of PVM strain 15 were mutated in a variety of combinations with a view to fusing these mutated fragments to the 5' end of the E. coli β-galactosidase gene that lacks its own initiation codon

Accelerated ageing is associated with increased COVID-19 severity and differences across ethnic groups may exist

BackgroundWhile increased age is an established risk factor for COVID-19, there is great heterogeneity in outcomes within age groups. This is because chronological age does not reflect health, unlike biological age. We intend to investigate the association between accelerated ageing and COVID-19 outcomes through the lens of three measures, namely phenotypic age acceleration (PhenoAgeAccel), telomere length (Adjusted T/S Ratio) and facial ageing, and to examine whether there are differences across ethnic groups.MethodsTaking participants from the UK Biobank, we associated accelerated ageing with severe COVID-19 outcomes, defined as COVID-related hospitalisation or death. Separate logistic regressions models were created for age and the three accelerated ageing-related variables, adjusting for a variety of covariates in each model. Multivariable logistic regression models were also created within White, Black, Asian and Other ethnic groups to assess for potential differing associations. Forward likelihood ratio logistic regression models were created to evaluate importance of the variables and to assess for patterns of association across the total population and ethnic groups.ResultsAfter adjusting for all covariates, the odds ratio (OR) and 95% confidence interval (95% CI) of COVID-19 severe outcomes for age was 1.080 (1.074–1.086). After further adjusting age for the accelerated ageing variables, the ORs were 1.029 (1.020–1.039) for PhenoAgeAccel and 0.847 (0.772–0.929) for Facial Ageing's “Younger Than You Are” while Adjusted T/S ratio and “Older Than You Are” were statistically insignificant. The OR for age remained similar across ethnic groups. Both PhenoAgeAccel and younger facial ages in the White population and PhenoAgeAccel in the Black population had ORs of 1.031 (1.021–1.042), 0.853 (0.774–0.939), and 1.049 (1.001–1.100), respectively. Both Adjusted T/S Ratio and older facial ages showed statistical insignificance in all ethnicities. In forward logistic regression, age and PhenoAgeAccel were the age-related variables selected most frequently in all models.InterpretationAccelerated ageing is associated with increased COVID-19 severity. The mechanisms at work here are likely immunosenescence and inflamaging. This association indicates that anti-ageing treatment may improve COVID-19 outcome. The results within ethnic groups and that of telomere length were inconclusive, but point to a need for future, more focused research on the topic