117,374 research outputs found
On the semantics of durational actions
No full textAbstractThis paper develops a mathematical framework to describe and reason about semantic theories of processes where actions have a non-zero duration. The framework relies on the notions of reduction and observability and allows one to naturally explain the possible choices to incorporate timing information in terms of process interaction mechanisms. The framework provides a parameterized context where well-known and new theories can be formally compared and classified by a suitable instantiation of the parameters. A proof-technique to derive from the reduction semantics an equivalent SOS-based characterization is also provided
Development of climate-based thermal comfort ranges from existing data: Analysis of the Smart Controls and thermal comfort (SCATS) database
No full textDespite the multifaceted nature of notion of thermal comfort, designers have embraced a very strict definition of it, which consists of very tight and static environments, were transition and stimuli are not admitted, and with very narrow ranges of microclimatic parameters required equally for all the subjects. This neglects all the potential implications related to different users. However, when it comes to thermal comfort, the long-term history of subjects and their climatic background play a pivotal role towards their own thermal sensations and preferences. In this work, to address these diversities, the authors analysed the existing database of the Smart Controls and Thermal Comfort (SCATS) project, which was built from monitoring and survey campaigns conducted in the late 90s in five different European countries. Data were studied by means of statistical techniques to grasp and define the potential combined influence of climatic location, seasonal variations, subjective variables and ventilation modes on the occupants’ thermal feeling and preference. Different scenarios recommended by standard EN 16798 were tested to address the differences in the thermal feelings of users living in different European countries. Finally, country-based operative temperatures that optimize users’ thermal feeling and preference were determined. Results highlight that users in different countries differently evaluate indoor thermal parameters both in terms of thermal feeling and thermal preferences. This results in differences among countries for acceptability levels associated with standardised indoor conditions. Furthermore, the results highlight the importance of air movement to improve acceptability at higher indoor temperatures for all the countries
The role of the reference building in the evaluation of energy efficiency measures for large stocks of public buildings
No full textWith the last European Directive 2018/844/EU, EU Member States have to outline effective strategies for the energy renovation of existing buildings, so as to achieve the objectives set respectively for 2030, 2040 and 2050, taking advantage of new financing instruments. In this process, public buildings are identified as important drivers for energy-behavioural changes among citizens and, in addition, they can benefit from encouraging mortgages for certified energy efficient renovations. However, the problem of dealing with existing public buildings is their sample size combined with the current necessity of significant renovations. In this scenario, the reference building acquires a key role as the starting model for the evaluation of primary energy needs and of retrofit measures. In this work, a reference building selected by a previous work is further analyzed, testing selected potential retrofit interventions by means of model simulation. The implemented measures are then evaluated using a cost-optimal approach, in order to integrate their priority with respect to cost-effectiveness. The aim of the work is to test on a building centrotype selected retrofit measures, to be then extended to the other buildings similar for their main geometrical and thermophysical features
Analysis of communication models in web service compositions
No full textIn this paper we describe an approach for the verification of Web service compositions dened by sets of BPEL processes. The key aspect of such a verification is the model adopted for representing the communications among the services participating in the composition. Indeed, these communications are asynchronous and buffered in the existing execution frameworks, while most verication approaches assume a synchronous communication model for efficiency reasons. In our approach, we develop a parametric model for describing Web service compositions, which allows us to capture a hierarchy of communication models, ranging from synchronous communications to asynchronous communications with complex buffer structures. Moreover, we develop a technique to associate with a Web service composition the most adequate communication model, i.e., the simplest model that is sufficient to capture all the behaviors of the composition. This way, we can provide an accurate model of a wider class of service composition scenarios, while preserving as much as possible an efficient performance in verification
A Minimalist Approach to Semantic Annotations for Web Processes Compositions
No full textIn this paper we propose a new approach to the automated composition of distributed processes described as semantic web services. Current approaches, such as those based on owl-s and wsmo, in spite of their expressive power, are hard to use in practice. Indeed, they require comprehensive and usually large ontological descriptions of the processes, and rather complex (and often inefficient) reasoning mechanisms. In our approach, we reduce to the minimum the usage of ontological descriptions of processes, so that we can perform a limited, but efficient and useful, semantic reasoning for composing web services. The key idea is to keep separate the procedural and the ontological descriptions, and to link them through semantic annotations. We define the formal framework, and propose a technique that can exploit simple reasoning mechanisms at the ontological level, integrated with effective reasoning mechanisms devised for procedural descriptions of web services.
This work is partially funded by the European project FP6-507482 “Knowledge Web” , by the MIUR-FIRB project RBNE0195K5, “Knowledge Level Automated Software Engineering”, and by the MIUR-PRIN 2004 project “Advanced Artificial Intelligence Systems for Web Services”
Evaluation of the Indoor Thermal Quality in high schools buildings: strengths and limits of different assessment methods
No full textRecent studies have pointed out how much the indoor environmental quality in schools’ classrooms is an important factor which could prevent serious adverse effects not only on the students’ comfort sensation, but also on their health and learning potential. However, although standards EN ISO 7726:2001, EN ISO 7730:2005 and EN 10551:2001 give recommendations about how to practically perform objective and subjective measurements, on the evaluation of the level of comfort perceived in buildings, there is the need to define a systematic and standardized way in order to implement the comfort assessment through a methodical and uniform approach. In this work the assessment of the Indoor Thermal Quality of two classrooms in one high school located in Treviso, a town in the North-East of Italy, is presented in order to highlight the strengths and the limits of two different evaluation approaches: field monitoring, survey questionnaires. To reach the aim, two monitoring and surveys campaigns were carried out, one during the spring and one during the heating season. All the four comfort areas were investigated through the questionnaires: the thermal, the visual, the acoustic and the air quality perception.. Afterwards objective and subjective responses on thermal and visual perception have been compared
CLAM: Managing Cross-layer Adaptation in Service-Based Systems
No full textService-based systems (SBS) have a complex layered structure where the service-based application (SBA) is implemented through a composition of services, which run on top of service oriented infrastructures. Taking into account the heterogeneous and dynamic execution context of such complex systems, adaptation is not straightforward. While several state-of-the-art adaptation approaches, unaware of each other, target different problems at specific parts of the system, the isolated enactment of those adaptations results in ignoring the overall impact of the adaptation on the whole SBS. In this work, we propose an approach that introduces a cross-layer adaptation manager (CLAM) to tackle this issue. The approach relies on a cross-layer meta model of the SBS and a set of predefined domain specific rules to integrate and coordinate existing analysis and adaptation tools. It assesses the impact of an initial adaptation trigger at different system levels, and if needed, proposes additional adaptations, consistent with the overall system. The paper introduces the proposed approach and presents preliminary results on its first implementation with concrete analysis and adaptation tools
A framework to support the design of a regenerative indoor environment
No full textIn recent decades, a new generation of “green indoor” spaces has fulfilled the latest regulations and guidelines for a carbon-neutral society. Their targets are reachable through certifications embracing sets of measures and the adverse effects on occupants. Notwithstanding this, it has constituted a significant step forward in building design. However, the challenges given by climate change and the ecological crises lead to the need for new disruptive approaches to indoor design and function, enhancing human health and adopting regenerative design” at the forefront of buildings’ conception. Besides the positive energy-performance attributes, the creation of a Regenerative Indoor Environment utilizes appropriate construction technologies and systems, to reinforce human health, and enhance users’ experience. This regenerative paradigm shift foresees putting ecosystems at the centre and the users’ psycho-physiological wellbeing, thus magnifying their collaboration. Despite regenerative design gaining some attention, a framework towards its implementation promoting the actual performances of the indoor environment is still missing, and designers do navigate among guidelines with no apparent performance indicators to be achieved, technologies to be implemented, or methodologies for post-occupancy evaluations. These three levels, constituting a stepwise methodology, are addressed by the authors within the sections of this paper, and validated as an example of the office buildings’ typology. i) What characterizes a Regenerative Indoor Environment? ii) What technical solutions underpin the realization of a Regenerative Indoor Environment? iii) What methods or standards are crucial for its evaluation? With these premises, the paper contributes to supporting the creation of a regenerative indoor’ design, by sampling and outlining regenerative indoor performances to be obtained, describing the adequate tools to implement them, as well as by displaying approaches and solutions for their final verification
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