192 research outputs found

    Multi-Agent Based Modelling of an Endogenous-Money Economy

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    We present an agent-based model of a simple endogenous-money economy. The model simulates agents representing individual persons who can work, consume, invent new products and related production technologies, apply for a loan from the bank and start up a business. Through the interaction of persons with the firms, we simulate the production of goods, consumption and labour market. In order to achieve a significant level of realism of the simulations, the firms are modelled as adaptive agents using an effective reinforcement learning approach in continuous space. This setting allows us to explore how an endogenous-money economy can be built up from scratch, as an emergent property of actions and interactions among heterogeneous agents once money is injected into a non-monetary self-production (or barter) economy. In the paper, we first empirically investigate the learning capability of the firm agents. Then, we discuss the results of some computational experiments under different significant scenarios

    Multi-Agent Based Modelling of an Endogenous-Money Economy

    Get PDF
    We present an agent-based model of a simple endogenous-money economy. The model simulates agents representing individual persons who can work, consume, invent new products and related production technologies, apply for a loan from the bank and start up a business. Through the interaction of persons with the firms, we simulate the production of goods, consumption and labour market. In order to achieve a significant level of realism of the simulations, the firms are modelled as adaptive agents using an effective reinforcement learning approach in continuous space. This setting allows us to explore how an endogenous-money economy can be built up from scratch, as an emergent property of actions and interactions among heterogeneous agents once money is injected into a non-monetary self-production (or barter) economy. In the paper, we first empirically investigate the learning capability of the firm agents. Then, we discuss the results of some computational experiments under different significant scenarios

    Bacterial coinfections in dengue virus disease: what we know and what is still obscure about an emerging concern

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    Dengue virus is the most frequent arthropod-borne viral infection worldwide. Simultaneously to the growth of its incidence, cases of bacterial coinfection in dengue have been increasingly reported. The clinical course of dual infections may worsen for reciprocal interactions and delays in the diagnosis, so that clinicians should be aware of this eventuality. Therefore, we reviewed literature to provide an overview of the epidemiological, clinical, and physiopathological issues related to bacterial coinfections and bacteremia in dengue.Clinical studies and case reports regarding bacteremia and bacterial coinfections in dengue and the interactions between the pathogens published on PubMed were reviewed.We found 26 case reports, only 3 studies on concurrent bacteremia and 12 studies reporting data on bacterial coinfections in dengue. According to the three available studies, the 0.18-7 % of dengue infections are accompanied by concurrent bacteremia, while the 14.3-44.4 % of dengue-related deaths seem associated to bacterial coinfections. Comorbidities, advanced age, and more severe dengue manifestations could be risk factors for dual infections. A longer duration of fever and alterations in laboratory parameters such as procalcitonin, hyponatremia, leukocyte count, and renal function tests can raise the suspicion.Despite the real burden and consequences of this emerging concern is still not computable accurately due to the lack of a significant number of studies on large cohorts, clinicians need a greater awareness about it to early recognize warning signs, to properly use available diagnostic tools and to readily start antibiotic treatment able to prevent worsening in mortality and morbidity

    Multiple Regression Model to Predict Length of Hospital Stay for Patients Undergoing Femur Fracture Surgery at “San Giovanni di Dio e Ruggi d’Aragona” University Hospital

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    The economic cuts suffered by public health have in many cases led to the reduction of beds. In order to optimize the available resources, the length of stay (LOS) can be used as an efficiency parameter. The objective of this study is to predict the value of LOS using the clinical information that is generally supplied by a patient who is hospitalized following a fracture of the neck of the femur and to make a comparison with results obtained after the implementation of the new diagnostic-therapeutic-assistance pathway (DTAP). The analysis was conducted on data extrapolated from the information system of the University Hospital “San Giovanni di Dio and Ruggi d’Aragona” of Salerno (Italy). The results show promising outcome in the use of the proposed prediction models as a tool for determining an estimate of the LOS and support the decision making process and the management of hospital resources in advance. In addition, the comparison of between the two models can be used as an indicator to assess the efficiency of the implemented DTAP

    Neighbourhood park vitality potential: From Jane Jacobs's theory to evaluation model

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    We construct a method to evaluate the neighbourhood park vitality potential (NPV-potential), inspired by Jane Jacobs's theory of urban and park vitality. The evaluation model produces an aggregate score of NPV-potential by combining information on the extrinsic factors of vitality, related to the park's surrounding urban area, with evaluative judgements on the intrinsic factors, related to the park's internal organisation and design. To showcase and submit the evaluation model to a preliminary test drive, we further present the results of an application on three parks in the city of Cagliari, Italy. The computed NPV-potential and the effective use of the three parks, obtained from direct observation, show a good degree of agreement. While far from a robust validation, which would require more extensive empirical studies with larger and more internally variable samples of parks, the reported agreement between the potential and the observed vitality on the ground is a preliminary indication of the possible usefulness of the proposed evaluation method for urban planning and design

    Planning and design support tools for walkability: a guide for urban analysts

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    We present a survey of operational methods for walkability analysis and evaluation, which we hold to show promise as decision-support tools for sustainability-oriented planning and urban design. An initial overview of the literature revealed a subdivision of walkability studies into three main lines of research: transport and land use, urban health, and livable cities. A further selection of articles from the Scopus and Web of Science databases focused on scientific papers that deal with walkability evaluation methods and their suitability as planning and decision-support tools. This led to the definition of a taxonomy to systematize and compare the methods with regard to factors of walkability, scale of analysis, attention on profiling, aggregation methods, spatialization and sources of data used for calibration and validation. The proposed systematization aspires to offer to non-specialist but competent urban analysts a guide and an orienteering, to help them integrate walkability analysis and evaluation into their research and practice

    A DECISION SUPPORT TOOL ON DERELICT BUILDINGS FOR URBAN REGENERATION

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    Abstract. We present a decision suppport tool for the comparison and selection of projects of integrated renovation of derelict buildings and areas for the purpose of urban regeneration. Each project is defined as a subset of derelict properties to renovate together with their respective designated use, and is scored by the decision support tool on two criteria: expected effort and estimated effectiveness in terms of improved urban capabilities in the urban area of interest. The expected effort is estimated as a global transformation cost, factoring in legal and management overhead costs as well as possible economies of scale. The effectiveness in evaluated in terms of extension of urban capabilities centred on walkable distances. We have implemented a bi-objective evolutionary search algorithm to address the computational complexity of the problem of search for efficient (non-dominated) projects over the two criteria. For the purpose of illustration, we present an example case-study application on the historical core of the city of Sassari, Italy.</p

    Un sistema di supporto alla pianificazione e progettazione della walkability e dell’accessibilità pedonale

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    Il contributo propone un metodo e uno strumento per la valutazione della qualità della vita urbana basato sui concetti di walkability e di accessibilità pedonale di luoghi della città rilevanti con i quali estendere le capacità degli individui e partecipare concretamente alle urban opportunities. Il modello di valutazione utilizza i percorsi pedonali esistenti della rete viaria e valuta la loro qualità in base a diversi attributi importanti per la pedonalità. L’applicazione del sistema proposto al caso studio di valutazione del progetto di riorganizzazione della Segunda Circular (seconda circonvallazione) di Lisbona consente di mostrarne i possibili utilizzi e di trarre alcune riflessioni sulla base dei risultati ottenuti.We present a methodology and a tool for evaluating the quality of life in cities based on walkability and pedestrian accessibility of places which are relevant for people's capabilities. The evaluation model uses the actual pedestrian routes along the street network and considers their quality on several attributes important for their walkability. We furthermore demonstrate possible uses of the support system by reporting and discussing the results of a case-study assessment of a project for the Lisbon Segunda Circular (Second Rind Road).Peer Reviewe

    A Fuzzy Inference System for the Assessment of Indoor Air Quality in an Operating Room to Prevent Surgical Site Infection

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    Indoor air quality in hospital operating rooms is of great concern for the prevention of surgical site infections (SSI). A wide range of relevant medical and engineering literature has shown that the reduction in air contamination can be achieved by introducing a more efficient set of controls of HVAC systems and exploiting alarms and monitoring systems that allow having a clear report of the internal air status level. In this paper, an operating room air quality monitoring system based on a fuzzy decision support system has been proposed in order to help hospital staff responsible to guarantee a safe environment. The goal of the work is to reduce the airborne contamination in order to optimize the surgical environment, thus preventing the occurrence of SSI and reducing the related mortality rate. The advantage of FIS is that the evaluation of the air quality is based on easy-to-find input data established on the best combination of parameters and level of alert. Compared to other literature works, the proposed approach based on the FIS has been designed to take into account also the movement of clinicians in the operating room in order to monitor unauthorized paths. The test of the proposed strategy has been executed by exploiting data collected by ad-hoc sensors placed inside a real operating block during the experimental activities of the “Bacterial Infections Post Surgery” Project (BIPS). Results show that the system is capable to return risk values with extreme precision
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