Roberto Demontis

GRIDA3—a shared resources manager for environmental data analysis and applications

GRIDA3 (Shared Resources Manager for Environmental Data Analysis and Applications) is a multidisciplinary project designed to deliver an integrated system to forge solutions to some environmental challenges such as the constant increase of polluted sites, the sustainability of natural resources usage and the forecast of extreme meteorological events. The GRIDA3 portal is mainly based on Web 2.0 technologies and EnginFrame framework. The portal, now at an advanced stage of development, provides end-users with intuitive Web-interfaces and tools that simplify job submission to the underneath computing resources. The framework manages the user authentication and authorization, then controls the action and job execution into the grid computing environment, collects the results and transforms them into an useful format on the client side. The GRIDA3 Portal framework will provide a problem-solving platform allowing, through appropriate access policies, the integration and the sharing of skills, resources and tools located at multiple sites across federated domains.

Rethinking Transit Time Reliability by Integrating Automated Vehicle Location Data, Passenger Patterns, and Web Tools

This paper investigates time reliability at bus stops. Although it is typically evaluated from the transit providers viewpoint, it must also account for passengers, as required in recent service-quality norms. Hence, data on both bus arrival (or departure) times and passenger arrivals must be collected and processed. Automated vehicle location (AVL) systems can collect bus data, but several challenges must be addressed to effectively use them. Passenger arrival data can be collected by surveys or direct observations and processed to derive patterns. This paper proposes two novel time reliability metrics: the percentage of passengers receiving regular service (PPR) and the percentage of passengers receiving punctual service (PPP) for regularity and punctuality evaluations, respectively. They are determined by a methodology that collects and handles AVL data, computes passenger patterns from passenger arrival data, and integrates AVL data and patterns. Experiments highlight the viability of the novel evaluation metrics using about three million of real-world AVL records. Their results are reported by straightforward Web tools. A comparison with traditional metrics shows that PPR and PPP provide a more careful evaluation by using the passenger as a normalization basis for their outcomes. In the new paradigm of demand-oriented services, the proposed metrics are crucial to quantify the ability of operators to serve passengers.

Web Architecture of a Web Portal for Reliability Diagnosis of Bus Regularity

In high frequency transit services, bus regularity—i.e., the headway adherence between buses at bus stops—can be used as an indication of service quality, in terms of reliability, by both users and transit agencies. The Web architecture is the entry point of a Decision Support System (DSS), and contains an environment designed for experts in transport domain. The environment is composed of tools developed to automatically handle Automatic Vehicle Location (AVL) raw data for measuring the Level of Service (LoS) of bus regularity at each bus stop and time interval of a transit bus route. The results are represented within easy-to-read control dashboards consisting of tables, charts, and maps, able to perform fast AVL processing and easy accessibility in order to reduce the workload of transit operators. These outcomes show the importance of well-handled and presented AVL data, in order to use them more effectively, improving past analysis done by using, if any, manual methods.