The JStar language philosophy

This paper introduces the JStar parallel programming language, which is a Java-based declarative language aimed at discouraging sequential programming, en-couraging massively parallel programming, and giving the compiler and runtime maximum freedom to try alternative parallelisation strategies. We describe the execution semantics and runtime support of the language, several optimisations and parallelism strategies, with some benchmark results

A Parallel semantics for normal logic programs plus time

It is proposed that Normal Logic Programs with an explicit time ordering are a suitable basis for a general purpose parallel programming language. Examples show that such a language can accept real-time external inputs and outputs, and mimic assignment, all without departing from its pure logical semantics. This paper describes a fully incremental bottom-up interpreter that supports a wide range of parallel execution strategies and can extract significant potential parallelism from programs with complex dependencies

Automatic Parallelization of Data-Driven JStar Programs

Data-driven problems have common characteristics: a large number of small objects with complex dependencies. This makes the traditional parallel programming approaches more difficult to apply as pipe-lining the task dependencies may require to rewrite or recompile the program into efficient parallel implementations. This thesis focuses on data-driven JStar programs that have rules triggered by the tuples from a bulky CSV file or from other sources of complex data, and making those programs run fast in parallel. JStar is a new declarative language for parallel programming that encourages programmers to write their applications with implicit parallelism. The thesis briefly introduces the JStar language and the implicit default parallelism of the JStar compiler. It describes the root causes of the poor performance of the naive parallel JStar programs and defines a performance tuning process to increase the speed of JStar programs as the number of cores increases and to minimize the memory usage in the Java Heap. Several graphic analysis tools were developed to allow easier analysis of bottlenecks in parallel programs. The JStar compiler and runtime were extended so that it is easy to apply a variety of optimisations to a JStar program without changing the JStar source code. This process was applied to four case studies which were benchmarked on different multi-core machines to measure the performance and scalability of JStar programs

Datalog as a parallel general purpose programming language

The increasing available parallelism of computers demands new programming languages that make parallel programming dramatically easier and less error prone. It is proposed that datalog with negation and timestamps is a suitable basis for a general purpose programming language for sequential, parallel and distributed computers. This paper develops a fully incremental bottom-up interpreter for datalog that supports a wide range of execution strategies, with trade-offs affecting efficiency, parallelism and control of resource usage. Examples show how the language can accept real-time external inputs and outputs, and mimic assignment, all without departing from its pure logical semantics

Increasing the Reliability of Software Systems on Small Satellites Using Software-Based Simulation of the Embedded System

The utility of Small Satellites (SmallSats) for technology demonstrations and scientific research has been proven over the past few decades by governments, universities, and private companies. While the research and technology demonstration objectives that can be provided by these SmallSats are becoming similar to larger spacecraft, their reliability still falls behind. This is in part due to the reduced cost of SmallSat missions in comparison to large spacecraft, which requires cheaper components, rapid development schedules, and accepted risk. In these missions, the importance of the flight software is often overlooked, and the software is rushed through development and not fully tested to provide the reliability required for on-orbit operations. This research aims to investigate the common causes of failures on SmallSats, and to provide a solution to the problem of developing and testing reliable flight software, through the use of software-based simulation of the full embedded satellite system. Through the course of this research, an open-source product was developed and released to the public to assist SmallSat missions, which is currently in use by public and private institutions across the country. The resulting product, the NASA Operational Simulator for Small Satellites, commonly referred to as NOS3, will be discussed in detail. The results of NOS3 will be viewed through a case study of the application of NOS3 to a SmallSat mission

Socioeconomic Impacts on Healthy Ageing in the US, England, China and Japan

Background and Aims Healthy ageing has become a popular topic worldwide. So far, a consensus definition of healthy ageing has not been reached. Socioeconomic position (SEP) is an important determinant of healthy ageing. Previous studies have indicated that people in advantaged SEPs are more likely to achieve healthy ageing than people in disadvantaged SEPs. However, only rare studies have compared the magnitude of socioeconomic inequalities in healthy ageing across countries. This thesis aims to conduct a cross-country comparison of socioeconomic inequalities in healthy ageing in the US, England, China and Japan. Data Sources The data are from the Health and Retirement Study (HRS), the English Longitudinal Study of Ageing (ELSA), the China Health and Retirement Longitudinal Study (CHARLS) and the Japanese Study of Ageing and Retirement (JSTAR). The analysis includes 10305 HRS respondents (waves 7–12, 2004–2014), 6590 ELSA respondents (waves 1–7, 2002–2015), 5930 CHARLS respondents (waves 1, 2 and 4, 2011–2015) and 1935 JSTAR respondents (waves 1–3, 2007–2011) aged 60 years or more at baseline. Methods A healthy ageing index (HAI) was created as the main outcome. Education, income, wealth and occupation were included as the main exposures. Data harmonisation was conducted. A two-fold fully conditional specification algorithm was employed to deal with missing data in socioeconomic indicators and covariates (Chapter 2). Pearson’s r and Cronbach’s α were calculated to check the HAI’s test-retest reliability and internal consistency respectively. A Receiver Operating Characteristic curve analysis and a Cox proportional hazards model were applied to test the HAI’s predictive performance on mortality risks (Chapter 3). Multilevel modelling was applied to assess the longitudinal relationships between SEPs and the HAI, allowing for random slopes and intercepts. Socioeconomic rank scores were derived and the slope indices of inequality were calculated to compare the magnitude of inequalities in healthy ageing by education, income and wealth across countries (Chapter 4). Path analysis was used to assess the mediating effects of occupation, income, wealth, smoking and drinking on the relationship between education and healthy ageing. The total, direct and indirect effects of education, occupation, income and wealth on healthy ageing were also calculated (Chapter 5). Results Japanese and English participants achieved healthier ageing than American and Chinese participants. A positive socioeconomic gradient in healthy ageing existed in all countries. The socioeconomic inequality in healthy ageing was relatively small in Japan. In China, the inequality in healthy ageing, especially by education, is daunting. Education was a universally influential socioeconomic predictor of healthy ageing, and is likely to be an independent predictor of healthy ageing among the ageing population across all countries. There were complex pathways from education to healthy ageing in the four countries. The positive effects on healthy ageing of improving education should not be neglected. Wealth inequality in healthy ageing was greater in England than in any other country. Wealth was more influential than income in predicting inequalities in healthy ageing in the US, England and Japan, while income was more influential than wealth in China. Labour force non-participation (e.g. retirement, disability) had negative effects on healthy ageing in the US. Chinese people in paid and stable work were healthier than those in unpaid farming work in later life. Implications This research provides sufficient theoretical and methodological guidelines for the development of well-suited assessments of healthy ageing in the area of public health. These guidelines will be useful for policymakers to capture key elements of healthy ageing when developing ageing policies for older people’s health, social participation and security. This research also provided a unique opportunity to conduct a multinational comparison of socioeconomic impacts on healthy ageing between Western and Asian countries, which has never been done before. Identifying influential socioeconomic indicators of healthy ageing in each country is instructive for exploring universal and country-specific public health practices to support healthy ageing in both Western and Asian countries

Requirements Modeling Methodology Based on Knowledge Engineering: A Case Study of Railway Control System

The complexity of the verification and the validation of embedded systems is increasing. This paper explores the first requirements engineering processes in the solution domain, which are analysis and specification. In this work we present an architecture of a requirement specification system. We show how the requirements are analysed and structured to generate a dependency graph. This latter will serve to analyse requirements and to model specifications on goal model. In this paper we will focus on the analysis, and structuring processes. We will explain the requirement classification criteria. Keywords: Requirements Modeling, Qualification Strategy, Knowledge Engineering, Ontology, Dependency Graph, Embedded System, ERTMS/ETC

Conflict or solidarity? Intergenerational relations in the face of population ageing. A comparison of Germany and Japan.

Summary This dissertation investigates whether population ageing is associated with a distribution-based intergenerational conflict. While comparing two pioneers of ageing, Germany and Japan, the analysis attempts to show tendencies that are relevant for a wider set of countries amid their own demographic developmental paths. Studying intergenerational relations on both the societal and the family level, this analysis is more nuanced than previous studies. A two-dimensional typology is proposed to define four ideal scenarios of intergenerational relations, of which intergenerational conflict is one case (consisting of weak solidarity on both the societal and the family level). Narrowing down the scope of analysis from the aggregate to the family and individual level, intergenerational solidarity is first presented based on National Transfer Accounts data. This discussion shows how public and private (financial) transfers secure the lives of individuals over the life cycle with elderly persons being net receivers of public transfers and net donors of private transfers. Onwards, the evolution of intergenerational solidarity is discussed in the context of political, economic and institutional factors, such as family. On the societal level, this study draws on the literature of labour market dualisation, Rueda’s insideroutsider model, and Mannheim’s concept of political generations. Based on data from the International Social Survey Programme, spanning over 20 years (1996-2016), policy preferences regarding government expenditure on old-age are found to differ with regard to age, cohort and employment status. Results show that intergenerational societal solidarity has remained strong in Germany but has vanished in Japan. On the family level, intergenerational relations are studied based on theories of saving and transfer giving, together with the concepts of social care and de-familialisation policies. Using data from the Survey of Health, Ageing and Retirement in Europe and the Japanese Study of Aging and Retirement, covering 11 (2004-2015) and 6 years (2007-2013) respectively, financial and non-financial transfer giving between generations is scrutinised. Results show strong solidarity within families for both countries. In comparison, Germany appears to find itself in a more favourable position to sustain its unwritten contract of intergenerational sharing consisting of the public and private sector. In Japan, signs of a political generation are emerging, whose interests differ significantly from those of older generations regarding the role of the welfare state. Developments in Japan may have repercussions for the design of the welfare state in years to come. [...

Logic-based optimal control for shipboard power system management

The capability to dynamically reconfigure future naval integrated electric power systems is central to the Navy’s vision of the future combat ship. The objective in this thesis is to design, implement and evaluate a Shipboard Power System Management system that will prevent loss of power at critical buses when damage conditions are encountered. The approach that we are proposing is based on a new paradigm for the design of optimal control systems for hybrid systems, i.e., systems composed of continuous dynamics and discrete events. Discrete events may involve external disturbances, the discrete action of protection devices or control systems. The essence of the idea is that the discrete acting subsystems are naturally associated with a set of logical conditions or logical and the continuous system dynamics are usually described by differential equations or differential-algebraic equations. We will introduce a dynamic programming method forhybrid systems that solves dynamic optimization problems involving both binary and real variables. The stability analysis of the hybrid control systems is conducted via bifurcation control analysis. The state feedback controller strategy for the mode switching of the power system is obtained through Mixed Integer Dynamic Programming. It is computed in the form of a lookup table that represents a mapping from combinations of modes, and continuous states to the required switching actions. Simulations results will be analyzed.Ph.D., Mechanical Engineering -- Drexel University, 200