Three experiments arranged a concurrent chained schedule that probabilistically arranged reinforcement or extinction. In Experiments 1 and 2, the probability of obtaining food in the terminal link period, following a given left or right lever choice, was the complement of the probability that the initial link choice would produce a transition to the terminal link. Also, the probability of reinforcement in the terminal link was either signaled or unsignaled, depending upon condition. In Experiment 1, a steady-state environment kept the relative probabilities of reinforcement constant within-session and Experiment 2 varied the relative probabilities of reinforcement within-session. Experiment 3 arranged equal rates of terminal link transition to either a signaled-reinforcement or an unsignaled-reinforcement terminal link. The location of the signaled option and the relative probabilities of reinforcement changed within-session. The signaled option produced either a reinforcement-correlated terminal link stimulus (i.e., conditional reinforcement) or an extinction-correlated terminal link stimulus. The unsignaled alternative produced the same terminal link stimulus regardless of the outcome. Overall, Experiments 1 and 2 demonstrated that rats frequently favor the option providing higher rates of terminal link transition at the expense of the probability of terminal link unconditional reinforcement. However, in Experiment 2, this tendency was reduced when the probabilities of reinforcement were signaled, suggesting weak control by conditional reinforcement. Experiment 3 did not show preference for the reinforcement-correlated signaled option in rats. Rather, it appears overall preference was controlled by an avoidance of the extinction-correlated option.

The present study evaluated the effectiveness of and preference for choice during a response-acquisition tasks with children who have a developmental disability. The conditions compared involved (a) delivery of a high-preferred item identified at the start of the study (high preferred), (b) delivery of a high-preferred item identified immediately prior to each session (pre-session), (c) delivery of a high-preferred item identified immediately following each session (post-session), and (d) no delivery of a high-preferred item (control). The results regarding effectiveness were inconclusive due to high levels of responding during the control condition. The results regarding choice showed both participants preferred the pre-session choice condition, and one participant also preferred the high-preferred condition.

Highly dynamic and complex computing systems are increasingly needed and are relied upon in daily life. One such system is the dynamic network, particularly in communication, in which it has widespread applications, such as: Internet, peer-to-peer networks, mobile networks and wireless networks. Dynamic networks consist of nodes and edges whose operating status may change over time; the edges may be unreliable and operate intermittently. Message-passing in such networks is inherently difficult and reasoning about the behaviour of message-passing algorithms is also difficult and hard to analyse. Their behaviour and correctness are hard to formulate and establish. To undertake formal reasoning about such systems, abstract models are essential in order to separate the general reasoning about message routing and the updating of routing tables from the details of how these are implemented in particular networks. This thesis proposes a new approach to modelling and reasoning about dynamic networks as follows. It develops a series of abstract models which makes it possible to focus on the correctness of routing methods. It models the dynamic network as a “demonic” process which runs concurrently with routing updates and message-passing, to express dynamic networks as concurrent systems. This allows the use of temporal logic and fairness constraints to reason about dynamic networks. To do so, it introduces a modal logic and formulates concepts of fairness which capture network properties. The correctness of dynamic networks means that under certain conditions, all messages will eventually be delivered. Formulating networks as concurrent systems means can establish the correctness for networks that never cease to change. Modelling at that one level of abstraction means being able to prove the properties of networks independently of the mechanisms in actual networks. Therefore, it provides “a factorisation” of proofs of correctness for actual dynamic networks. The models are implemented as multi-threaded programs, and then adopted an experimental runtime verification tool called RULER to test whether model instances satisfy the modal correctness for message delivery.

The autism spectrum disorder (ASD) diagnostic classifications, according to the DSM-5, include a severity rating. Several screening and/or diagnostic measures, such as the autism diagnostic and observation schedule (ADOS), Childhood Autism Rating Scale (CARS) and social responsiveness scale (SRS) (teacher and parent versions), include an assessment of symptom severity. The purpose of this study was to examine whether symptom severity and/or diagnostic status of preschool-aged children with ASD (N = 201) were similarly categorized on these measures. For half of the sample, children were similarly classified across the four measures, and scores on most measures were correlated, with the exception of the ADOS and SRS-P. While the ADOS, CARS, and SRS are reliable and valid measures, there is some disagreement between measures with regard to child classification and the categorization of autism symptom severity.

A system generation utility has been developed to assist students in producing IBM PC-based multitasking applications targeted for the small operating system (SOS) developed by Jerry E. Sayers. Our aim is to augment SOS by enabling a student to interactively tailor the characteristics of the operating system to meet the requirements of a particular application. The system allows the user to adjust factors such as: initial state, priority, and scheduling method of concurrently executed tasks, and. also, use of system resources. A custom operating system is produced by invoking a MAKE utility to bind SOS with application-specific code, in addition to intermediate source code created during the system generation process. Testing of the system included implementing an application that adds column vectors in a 5 x 5000 matrix concurrently. Further testing involves using the system generation utility along with SOS as part of an undergraduate operating systems class at East Tennessee State University.

The study of choice and allocation has often focused on certain parameters of reinforcement, but rarely on historical variables. The goal of this study was to investigate the potential effects of gradual vs. abrupt teaching methods on future response allocation. A secondary goal was to see if the results of teaching-method manipulations might be correlated with the parameters that the teaching method produced, specifically unit costs, rate of reinforcement, or error rates. Results indicate that these teaching procedures can produce transient shifts in allocation, but not in a consistent direction. Neither unit cost nor rate or reinforcement alone can account for observed response allocation shifts after training. Researchers saw that subjects reliably shifted towards a manipulanda that produced higher rates of errors, therefore investigating the influence that error rate (or types of errors) may have on response allocation may aid in general teaching method preferences. Future research could focus on the combination of historical procedural variables and current variables that could determine response allocation.

Principles of concurrent development are applied to the design of a small-scale device for converting natural gas or liquefied petroleum gas into hydrogen. The small hydrogen generator is intended for serial production for application in the production of industrial hydrogen, fueling stationary fuel cell power systems and refueling hydrogen-fueled fuel cell electric vehicles. The concurrent development process is contrasted with the traditional, linear development process for petrochemical systems and equipment, and the design is benchmarked against existing small hydrogen generators as well as industrial hydrogen production apparatus. A novel system and hardware design are described, and a single cycle of concurrent development is applied in the areas of catalyst development, thermodynamic optimization, and reactor modeling and design. The impact of applying concurrent development techniques is assessed through economic modeling, and directions for future development work are identified. / Ph. D.

Programas concorrentes possuem características que os diferenciam de programas sequenciais, tornando a atividade de teste mais complexa. Questões como definição e uso de variáveis por diferentes processos, comunicação, sincronização e comportamento não-determinístico precisam ser consideradas. Apesar dos avanços obtidos nesse contexto, um problema que ainda persiste é o custo da atividade de teste, relacionado principalmente ao número excessivo de elementos requeridos a serem testados. Neste contexto, este trabalho apresenta duas propostas: a primeira estática, focando na detecção automática de elementos requeridos não-executáveis, para os critérios relacionados a sincronizações; e a segunda dinâmica, aplicando-se o teste de alcançabilidade para apoiar a avaliação da cobertura de sequências de sincronizações, desse modo, usando informações dinâmicas para apoiar o teste de cobertura. Estas propostas foram implementadas na ferramenta ValiMPI e um experimento foi realizado a fim de verificar a eficácia da proposta. Os resultados indicam que as duas propostas implementadas neste trabalho são promissoras e auxiliam a reduzir o custo da atividade de teste / Concurrent programs present new features, such as: nondeterminism, concurrency, synchronization and communication. These features need to be considered during testing activity, making this activity more complex. Despite the results achieved in this context, a problem that still remains is the application cost of the testing, especially the cost related to the high number of required elements generated by the test criteria proposed to concurrent programs. In this context, this work presents two contributions: the first one using a static approach, automatically detecting non-executable elements related to synchronization between process; and the second one using a dynamic approach, applying reachability testing to support the coverage evaluation of the executed sequences, reducing the number of executed sequences and the number of test cases. These contributions were implemented in the ValiMPI tool and experiments were conducted to evaluate them. The results indicate that these contributions can improve the concurrent program testing, reducing the application cost of the testing activity

Nowadays in a turbulent market, developing and launching a new product is one of most competitive strategies implemented by many large and small enterprises. In fact, launching a new product depends upon the performance of four critical functions: design, manufacturing, distribution and marketing. Their performances would increase or decrease the total time-to-market and consequently time-to-money. Time-to-market would be improved if the manufacturing system can diminish time-to-volume/quality/cost during production start-up phase. In order to overcome the impediment during a start-up phase, the significant parameters which are influencing a production start-up phase should be identified and managed. Hence, a system-wide approach would facilitate a product realization process so as to achieve global optimization throughout the entire process. One of such systems is Concurrent Engineering which can be applied owing to being enable to choose the best practice to improve product introduction process, being capable to improve cross functional integration and communication, and being empowered to apply a set of comprehensive methods for design analysis so that designers can select the most optimal design solution which is not only considering the design constraints, but also taking the constraints of production system, logistics and distribution into account. Hence, it can cover majority of problems in start-up phase which are generated due to lack of empathy between design and manufacturing. This research studied the significant parameters influencing a production start-up phase. Then, it investigated whether the principle of concurrent engineering would support an efficient start-up phase. The selected research methodology is based on a conceptual and supportive literature review of the current scholars. The research design is according to a three-step process which is applied to catch most relevant literatures. The research implements an analogy reasoning logic to establish the outcome of the research through the comparison between principles of a concurrent engineering program and significant parameters. As a result of the research, the significant parameters are identified, in addition, a managerial framework is structured that can present the requirements to manage an efficient start-up phase. Moreover, the results indicate how a concurrent engineering program would support a start-up phase.

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