Specification and implementation of concurrent systems using PARLOG

Process-oriented design and implementation of concurrent systems has important benefits. However, the inherent complexity of concurrent processes’ communication imposes challenges such as verifying consistency between the process-oriented design and implementation of a concurrent system. To deal with such a challenge, we use Galois connections, Failures and Category Theory to construct a formal framework for designing, implementing, analyzing and verifying consistency of concurrent systems. For the purpose of illustrating the framework, a running concurrent system is designed by Communicating Sequential Processes, implemented by a process-oriented programming language Erasmus.

The lack of formalism and rigor in existing multi-agents models often leads to ambiguities and different interpretations. Those weaknesses combined with the inherent complexity of multi-agents systems generate many problems in their development process. Using formal notations to specify multi-agents systems’ behavior makes it possible to produce precise description. This also offers a better support to their verification and validation process. The Maude language, based on rewriting logic, presents a rich notation supporting formal specification and implementation of concurrent systems. In this paper, we demonstrate the feasibility and the interest of formalizing the behavior of DIMA model’s agents with the Maude language. The elaborated formal approach captures the inherent aspects of a DIMA model. The generated Maude descriptions have been validated using the platform supporting this language. Moreover, the proposed approach is generic and extensible. It offers, in particular, the advantage of being applicable to all multi-agents systems based on DIMA architecture and presents interesting extension possibilities.

Using Failures and Category Theory to Verify Process Communications between Design and Implementation of Concurrent Systems

High‐level language primitives for concurrent programming exist in languages such as Ada and Modula‐2. However, each of these languages provides only a single means for specifying multitasking and synchronization, essential in the implementation of concurrent systems. The SR language provides several mechanisms for specifying multi‐tasking and synchronization, so it can be used to explore the performance of various communication techniques.This paper presents performance results for SR's multi‐tasking and synchronization mechanisms and discusses the effects of the generated code, the run‐time support and the hardware on these results. These results are compared with those for similar mechanisms in other languages, leading to some general conclusions about the performance of process communication primitives. These performance results can be used by programmers to make design choices that allow systems programs written in high‐level languages to meet real‐time performance specifications.

Model-Checking of Correctness Conditions for Concurrent Objects

Delta Prolog is a concurrent logic programming language founded on the theoretical model of Distributed Logic and extending the Prolog language in order to allow the specification of concurrent systems. This paper describes Delta Prolog, its operational semantics and a sequential abstract machine (DAM) for the language.

Performing formal verification of concurrent systems involves partial order logics (here MSO with partial orders) for the specification of properties or of the concurrent system itself. A common structure for the verification of concurrent systems is so-called pomset. A pomset is a multiset of partially ordered events. The partial order relation describes causal dependencies of events. We propose a new word based model, namely Pre-Post-Pomset, making the exploration of pomsets space possible. In this paper, our new model stands to be a general model in the sense that some classical models used in the specification of concurrent systems (Synchronized product of systems, Mazurkiewicz traces or parallel series) can be specified within. Besides its general aspect, our model offers decidability results on the verification problem according to an MSO formula on pomsets.

A LONGITUDINAL EXAMINATION OF HOW HOSPITAL PROVISION OF HOME HEALTH SERVICES CHANGED AFTER THE IMPLEMENTATION OF THE BALANCED BUDGET ACT OF 1997: DOES OWNERSHIP MATTER? By Tiang-Hong Chou, Ph.D. A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University. Virginia Commonwealth University, 2009 Dissertation Director: Kenneth R. White, Ph.D., FACHE. Professor, Department of Health Administration By using a natural experiment approach and longitudinal national hospital data, this study sheds light on the objective functions of hospitals with different ownership forms by comparing their relative reductions in HH provision after the implementation of the BBA. The empirical findings reveal that for-profit hospitals behave differently as compared to public and private nonprofit hospitals, due to their different operational objectives. While the response of for-profit hospitals is consistent with the profit-maximizer model, both public and private nonprofit ownership types behave consistently in accordance with the model of two-good producers whose objective is to maximize market outputs for meeting the health care needs of the community, given the break-even requirement. This finding provides support for the tax exemption the United States government has granted private nonprofit hospitals. Although the response patterns of the nonprofit ownership types are in general similar, this study found that, contrary to expectation, religious hospitals were more likely than secular nonprofit hospitals to have reduced HH provision after the BBA. Further studies are needed to explore the difference in operational behaviors between these two ownership types. Built on previous related studies and applying a more comprehensive set of independent and control variables with improved data sources, this study is able to examine the effects of certain organizational and market factors on hospital offering of HH care pre-BBA and the change in the provision of HH care in the six years following the implementation of the BBA. Hospital proportion of Medicare patients, hospital size, total profit margin, case mix index, elderly density in the market are found to be positive determinants of a hospital‘s likelihood of offering HH care. However, these organizational and market factors, in general, play a non-significant role in influencing hospitals‘ changes in HH care provision after the implementation of the BBA. In the study, explanations and implications of these finding are discussed. Finally, potential limitations to this study and opportunities for future research are addressed. CHAPTER 1: INTRODUCTION

Software modernization powered by dynamic language product lines

This article presents the implementation of a control system for a multirotor unmanned aerial vehicle with a controller and an object recognition system based on Python programming language. The DJI Tello drone was used as the main drone to get accurate real-world values and see the operation behavior in practice. Multirotor drones are an integral part of the development of the modern world. This article presents a control model for an unmanned aerial vehicle using the Python programming language, which is based on object recognition using the OpenCV library and, based on the results, determining the trajectory of the quadrupole by the system itself. The work was carried out in accordance with the parameters of the DJI TELLO drone and the efficient operation of the algorithm in real conditions was demonstrated. To get the direction and speed of a multi-rotor unmanned aerial vehicle, in our case a four-rotor, 3 parameters are checked: roll, pitch, yaw, the latter is controlled using a comparative, integratordifferentiating controller.

Architectures based on Coordinated Atomic action (CA action) concepts have been used to build concurrent fault-tolerant systems. This conceptual model combines concurrent exception handling with action nesting to provide a general mechanism for both enclosing interactions among system components and coordinating forward error recovery measures. This paper proposes an architectural model to guide the formal specification of concurrent fault-tolerant systems. This architecture provides built-in CSP (Communicating Sequential Process) processes and predefined channels to coordinate exception handling of the user-defined components. As a result, a formal and general architecture supporting software fault-tolerance are ready to be used.

A reinforcement-learning model of active avoidance behavior: Differences between Sprague Dawley and Wistar-Kyoto rats

Organisational behaviour and strategies in the adoption of certified management systems: an analysis of the Spanish hotel industry

The Geospatial Information that service from public organizations and authorities are significantly increasing e.g., JPL OnEarth, GeoBrain, Google, and so on. Those geospatial information services rely on various existing Web technologies such as Web Service, OGC Web Services, REST, and GeoRSS. There are several formats of geospatial data which are published via the standard protocol HTTP such as GML, KML, Shapefile, and GeoTiff. Currently, a number of researches in geosciences community focus on geospatial services integration. The geospatial services integration is jointly defined and introduced by OGC and ISO TC 2111. The services integration is defined in term of service chaining: Transparent chaining, Translucent chaining, and Opaque chaining. This paper reports a research which focuses on Translucent chaining in which public user is allowed to predefine a service chain and execute it via Workflow enactment service. A process definition language is applied to coordinate across XML-based interfaces and support services chaining among Web Service, OGC Web Service, and REST. WPS-T (Transactional Web Processing Service as Workflow enactment service) is implemented and used to introduce a scalable framework. Complex geospatial operation can be managed by sequencing a number of simple operations from service itself or other services into a single operation. A geospatial service chain can then be executed as a single service operation, and it also can be invoked by other service chain. The implemented system is demonstrated to facilitate services chaining which is independent from any services interface.

Specification patterns have proven to help developers to state precise system requirements, as well as formalize them by means of dedicated specification languages. Most of the past work has focused its applicability area to the specification of concurrent and real-time systems, and has been limited to a research setting. In this paper we present the results of our study on specification patterns for service-based applications (SBAs). The study focuses on industrial SBAs in the banking domain. We started by performing an extensive analysis of the usage of specification patterns in published research case studies --- representing almost ten years of research in the area of specification, verification, and validation of SBAs. We then compared these patterns with a large body of specifications written by our industrial partner over a similar time period. The paper discusses the outcome of this comparison, indicating that some needs of the industry, especially in the area of requirements specification languages, are not fully met by current software engineering research.