Despite evidence to support physically active and passive leisure as significant contributors to well-being, for working mothers, fitting leisure into an already busy schedule can be challenging. The purpose of this study was to examine the influence of perceived time constraints and self-determination for physically active and passive leisure on conflict between these two leisure domains and the influence of this conflict on well-being among physically active working mothers. A total of 66 women who were physically active, worked at least 30 hours per week outside the home and had at least one child living in the home, participated in the study. At baseline, the participants completed a basic intake assessment in addition to validated questionnaires to measure time constraints and motivation for physically active and passive leisure. A two-week period of electronic experience sampling followed to evaluate leisure engagement. A final set of measures to evaluate conflict between physically active and passive leisure over the two weeks, and general well-being were completed at the end of the experience sampling period. Results indicated that despite relatively high levels of satisfaction with time available for both physically active and passive leisure, perceived time constraints were associated with increased goal conflict as are non-self-determined motivation for physically active leisure and self-determined motivation for passive leisure. Controlling for engagement in physically active and passive leisure, well-being is negatively influenced by goal conflict. Recommendations are provided regarding areas for additional research to further our understanding of the impact of opposing motivational orientations on goal conflict including the incorporation of Vallerand’s Dualistic Model of Passion (Vallerand et al., 2003). From a practical standpoint, the implications of the study results for interventions designed to address general well-being in middle class working mothers through targeting factors related to time constraints and goal conflict are discussed.

Despite evidence to support physically active and passive leisure as significant contributors to well-being, for working mothers, fitting leisure into an already busy schedule can be challenging. The purpose of this study was to examine the influence of perceived time constraints and self-determination for physically active and passive leisure on conflict between these two leisure domains and the influence of this conflict on well-being among physically active working mothers. A total of 66 women who were physically active, worked at least 30 hours per week outside the home and had at least one child living in the home, participated in the study. At baseline, the participants completed a basic intake assessment in addition to validated questionnaires to measure time constraints and motivation for physically active and passive leisure. A two-week period of electronic experience sampling followed to evaluate leisure engagement. A final set of measures to evaluate conflict between physically active and passive leisure over the two weeks, and general well-being were completed at the end of the experience sampling period. Results indicated that despite relatively high levels of satisfaction with time available for both physically active and passive leisure, perceived time constraints were associated with increased goal conflict as are non-self-determined motivation for physically active leisure and self-determined motivation for passive leisure. Controlling for engagement in physically active and passive leisure, well-being is negatively influenced by goal conflict. Recommendations are provided regarding areas for additional research to further our understanding of the impact of opposing motivational orientations on goal conflict including the incorporation of Vallerand’s Dualistic Model of Passion (Vallerand et al., 2003). From a practical standpoint, the implications of the study results for interventions designed to address general well-being in middle class working mothers through targeting factors related to time constraints and goal conflict are discussed.

In this study, we consider the Operational Fixed Job Scheduling Problem on identical parallel machines. The problem is to select a subset of jobs for processing among a set of available jobs with fixed arrival times and deadlines, so as to maximize the total weight. We analyze the problem under three environments: Working time constraints, Spread time constraints, and Machine dependent job weights. We show that machine eligibility constraints appear as a special case of the last environment. We settle the complexity status of all problems, and show that they are NP-hard in the strong sense and have several polynomially solvable special structures. For all problems, we propose branch and bound algorithms that employ powerful reduction mechanisms and efficient lower and upper bounds. The results of our computational runs reveal that, the algorithms return optimal solutions for problem instances with up to 100 jobs in reasonable solution times.

Heterogeneity in modern datacenters is on the rise, in hardware resource characteristics, in workload characteristics, and in dynamic characteristics (e.g., a memoryresident copy of input data). As a result, which machines are assigned to a given job can have a significant impact. For example, a job may run faster on the same machine as its input data or with a given hardware accelerator, while still being runnable on other machines, albeit less efficiently. Heterogeneity takes on more complex forms as sets of resources differ in the level of performance they deliver, even if they consist of identical individual units, such as with rack-level locality. We refer to this as combinatorial heterogeneity. Mixes of jobs with strict SLOs on completion time and increasingly available runtime estimates in production datacenters deepen the challenge of matching the right resources to the right workloads at the right time. In this dissertation, we hypothesize that it is possible and beneficial to simultaneously leverage all of this information in the form of declaratively specified spacetime soft constraints. To accomplish this, we first design and develop our principal building block—a novel Space-Time Request Language (STRL). It enables the expression of jobs’ preferences and flexibility in a general, extensible way by using a declarative, composable, intuitive algebraic expression structure. Second, building on the generality of STRL, we propose an equally general STRL Compiler that automatically compiles STRL expressions into Mixed Integer Linear Programming (MILP) problems that can be aggregated and solved to maximize the overall value of shared cluster resources. These theoretical contributions form the foundation for the system we architect, called TetriSched, that instantiates our conceptual contributions: (a) declarative soft constraints, (b) space-time soft constraints, (c) combinatorial constraints, (d) orderless global scheduling, and (e) in situ preemption. We also propose a set of mechanisms that extend the scope and the practicality of TetriSched’s deployment by analyzing and improving on its scalability, enabling and studying the efficacy of preemption, and featuring a set of runtime mis-estimation handling mechanisms to address runtime prediction inaccuracy. In collaboration with Microsoft, we adapt some of these ideas as we design and implement a heterogeneity-aware resource reservation system called Aramid with support for ordinal placement preferences targeting deployment in production clusters at Microsoft scale. A combination of simulation and real cluster experiments with synthetic and production-derived workloads, a range of workload intensities, degrees of burstiness, preference strengths, and input inaccuracies support our hypothesis that leveraging space-time soft constraints (a) significantly improves scheduling quality and (b) is possible to achieve in a practical deployment.

Este trabalho apresenta uma proposta de Arquitetura Orientada a Serviço para desenvolvimento de aplicações com restrições temporais, isto é, aplicações em que o tempo de resposta a uma requisição deve respeitar limites máximos. No desenvolvimento da arquitetura proposta foram considerados os modelos de filas com um único servidor e com múltiplos servidores, por meio da utilização de serviços redundantes e do escalonamento de requisições para melhoria do determinismo no tempo de resposta das requisições efetuadas. Para avaliação da arquitetura proposta foi construído um sistema de testes de forma a ser observado o comportamento do tempo de resposta das requisições em função do número de servidores disponíveis e sua respectiva taxa de utilização. Os resultados obtidos indicam que é possível obter um aumento no determinismo do tempo de resposta das requisições efetuadas (diminuição da dispersão de valores), tendo sido obtidos resultados semelhantes para os dois algoritmos de escalonamento utilizados: por ordem de chegada das requisições e SRPT (Shortest Remaining Processing Time). / This thesis presents a proposal for a Service Oriented Architecture applied to development of time constrained systems, where the timeliness of the results is a major requirement. The development is based on the queuing theory (models using one and multiple servers) and requests scheduling to improve response time determinism. In order to verify the proposal, a test system had been developed to observe the dynamic behavior of the requests response time dispersion according to the number of servers available and associated processing rate. The results obtained show an improvement over the request response time determinism and almost similar performance for the two scheduling algorithms used: request arrival order and SRPT (Shortest Remaining Processing Time).

Este trabalho apresenta uma proposta de Arquitetura Orientada a Serviço para desenvolvimento de aplicações com restrições temporais, isto é, aplicações em que o tempo de resposta a uma requisição deve respeitar limites máximos. No desenvolvimento da arquitetura proposta foram considerados os modelos de filas com um único servidor e com múltiplos servidores, por meio da utilização de serviços redundantes e do escalonamento de requisições para melhoria do determinismo no tempo de resposta das requisições efetuadas. Para avaliação da arquitetura proposta foi construído um sistema de testes de forma a ser observado o comportamento do tempo de resposta das requisições em função do número de servidores disponíveis e sua respectiva taxa de utilização. Os resultados obtidos indicam que é possível obter um aumento no determinismo do tempo de resposta das requisições efetuadas (diminuição da dispersão de valores), tendo sido obtidos resultados semelhantes para os dois algoritmos de escalonamento utilizados: por ordem de chegada das requisições e SRPT (Shortest Remaining Processing Time). / This thesis presents a proposal for a Service Oriented Architecture applied to development of time constrained systems, where the timeliness of the results is a major requirement. The development is based on the queuing theory (models using one and multiple servers) and requests scheduling to improve response time determinism. In order to verify the proposal, a test system had been developed to observe the dynamic behavior of the requests response time dispersion according to the number of servers available and associated processing rate. The results obtained show an improvement over the request response time determinism and almost similar performance for the two scheduling algorithms used: request arrival order and SRPT (Shortest Remaining Processing Time).

A problem when testing timeliness of event-triggered real-time systems is that response times depend on the execution order of concurrent tasks. Conventional testing methods ignore task interleaving and timing and thus do not help determine which execution orders need to be exercised to gain confidence in temporal correctness. This thesis presents and evaluates a framework for testing of timeliness that is based on mutation testing theory. The framework includes two complementary approaches for mutation-based test case generation, testing criteria for timeliness, and tools for automating the test case generation process. A scheme for automated test case execution is also defined. The testing framework assumes that a structured notation is used to model the real-time applications and their execution environment. This real-time system model is subsequently mutated by operators that mimic potential errors that may lead to timeliness failures. Each mutated model is automatically analyzed to generate test cases that target execution orders that are likely to lead to timeliness failures. The validation of the theory and methods in the proposed testing framework is done iteratively through case-studies, experiments and proof-of-concept implementations. This research indicates that an adapted form of mutation-based testing can be used for effective and automated testing of timeliness and, thus, for increasing the confidence level in real-time systems that are designed according to the event-triggered paradigm.

The purpose of this study is to show how the modern society, with demands, expectations and the time constraints of adults, affects children and the everyday life at the preschool. Our intention is also to show the importance of identify stress symptoms of the children.         The study is of qualitative empirical kind and is based on a questionnaire to 19 parents of preschool children at the age of three to five years old. Interviews are made with four preschool teachers on one preschool. An observation of children in possible stressful situations is made during three days each at two preschools.      The results show that the modern society affects children and can be stressful. It also affects the everyday life at the preschool. The results show the significance of having strategies to prevent stress at the preschool in order to create a balance between demands and expectations in the everyday life and time for recreation.

This thesis presents an intelligent early packet discard (I-EPD) for real-time video streaming over a multi-hop ad hoc network. In a multi-hop ad hoc network, the quality of transferring real-time video streams could be seriously degraded, since every intermediate node (IN) functionally like forwarding device does not possess large buffer and sufficient bandwidth. Even worse, a selected forwarding node could leave or power off unexpectedly which breaks the route to destination. Thus, a video packet temporarily buffered in intermediate nodes may exceed its time constraint when either a congested or failed link occurs; a stale video packet is useless even if it can reach destination after network traffic becomes smooth or failed route is reconfigured. In the proposed I-EPD, an IN can intelligently determine whether a buffered video packet should be discarded based on an estimated time constraint which is calculated from the RTP timestamps and the round trip time (RTT) measured by RTCP. For the purpose of validation, we implement the I-EPD scheme on a Linux-based embedded system. We compare the quality of video streams under different bit rates and different route repair time. In addition, we use PSNR to validate the quality of pictures from the aspect of application layer. The experimental results demonstrate that with I-EPD buffer utilization on IN can be more effectively used and unnecessary bandwidth wastage can be avoided.

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