Under which conditions is carrier cooperation possible? A case study in a Seville marketplace

The high volume of traffic originates two well-known problems in many cities: congestion and pollution. In recent years, a social phenomenon is emerging cooperation. This work is aimed at evaluating the circumstances under which transport cooperation is possible between different stakeholders operating in the same geographical area. To this end, a double survey process was conducted in a marketplace situated in the Seville City (Spain) centre. The first survey was designed to know the characteristics of the retailers and their preferences with respect to cooperation and regulations. A relational analysis between retailer features and their willingness to cooperate was carried out. After analysing the motivations for non-cooperation, a mixed proposal was designed and surveyed. Although the research was limited to a marketplace, the relevant data gathered from this double survey process highlights some implications: (a) the importance of personal relations in retailer cooperation; (b) a high volume of freight and the use of vans as on-street warehouses appear as significant motivations for non-cooperation; (c) forcing changes in the statu quo encourages cooperation.Ministerio de Economía y Competitividad (España) TEC2013-47286-C3-3-

A viral system to optimise the daily drayage problem

The intermodal transport chain can become more efficient by means of a good organisation of the drayage movements. Drayage in intermodal container terminals involves the pick up or delivery of containers at customer locations, and the main objective is normally the assignment of transportation tasks to the different vehicles, often with the presence of time windows. This paper focuses on a new approach to tackle the daily drayage problem by the use of viral system (VS). VS is a novel bio-inspired approach that makes use of a virus-infection biological analogy that is producing very satisfactory results when dealing with complex problems with huge feasibility region.Unión Europea TEC2013-47286-C3-3-

Enlarging instruction streams

The stream fetch engine is a high-performance fetch architecture based on the concept of an instruction stream. We call a sequence of instructions from the target of a taken branch to the next taken branch, potentially containing multiple basic blocks, a stream. The long length of instruction streams makes it possible for the stream fetch engine to provide a high fetch bandwidth and to hide the branch predictor access latency, leading to performance results close to a trace cache at a lower implementation cost and complexity. Therefore, enlarging instruction streams is an excellent way to improve the stream fetch engine. In this paper, we present several hardware and software mechanisms focused on enlarging those streams that finalize at particular branch types. However, our results point out that focusing on particular branch types is not a good strategy due to Amdahl's law. Consequently, we propose the multiple-stream predictor, a novel mechanism that deals with all branch types by combining single streams into long virtual streams. This proposal tolerates the prediction table access latency without requiring the complexity caused by additional hardware mechanisms like prediction overriding. Moreover, it provides high-performance results which are comparable to state-of-the-art fetch architectures but with a simpler design that consumes less energy.Peer ReviewedPostprint (published version

A satellite navigation system to improve the management of intermodal drayage

The intermodal transport chain can become more efficient by means of a good organization of the drayage movements. Drayage in intermodal container terminals involves the pick up or delivery of containers at customer locations, and the main objective is normally the assignment of transportation tasks to the different vehicles, often with the presence of time windows. The literature shows some works on centralised drayage management, but most of them consider the problem only from a static and deterministic perspective, whereas the work we present here incorporates the knowledge of the real-time position of the vehicles, which permanently enables the planner to reassign tasks in case the problem conditions change. This exact knowledge of position of the vehicles is possible thanks to a geographic positioning system by satellite (GPS, Galileo, Glonass), and the results show that this additional data can be used to dynamically improve the solution

Dynamic approach to solve the daily drayage problem with travel time uncertainty

The intermodal transport chain can become more e cient by means of a good organization of drayage movements. Drayage in intermodal container terminals involves the pick up and delivery of containers at customer locations, and the main objective is normally the assignment of transportation tasks to the di erent vehicles, often with the presence of time windows. This scheduling has traditionally been done once a day and, under these conditions, any unexpected event could cause timetable delays. We propose to use the real-time knowledge about vehicle position to solve this problem, which permanently allows the planner to reassign tasks in case the problem conditions change. This exact knowledge of the position of the vehicles is possible using a geographic positioning system by satellite (GPS, Galileo, Glonass), and the results show that this additional data can be used to dynamically improve the solution

Nuevos registros de asociaciones entre especies de Reduviidae (Hemiptera: Heteroptera) y plantas en Argentina

Almost all reduviids are predators; however, recent observations have shown that certain reduviids, particularly members of tribe Harpactorini (Harpactorinae) may be associated with specific plants as a strategy of predation and complementary nectarivory. These observations on the occurrence of the use of nectar as food source by various species of Reduviidae, mostly Harpactorini, in Argentina (Misiones), are recorded here. Additional records of oviposition and preying by Harpactorini and Bactrodinae species on certain plants are also provided.Casi todos los redúvidos son depredadores; sin embargo, varias observaciones han demostrado que algunas especies, en particular los miembros de la tribu Harpactorini (Harpactorinae), pueden estar asociados con plantas específicas como estrategia de predación y complementariamente la nectarivoría. Aquí se registran observaciones recientes del uso del néctar como fuente alimentaria por varias especies de Reduviidae, en su mayoría Harpactorini, en Argentina (Misiones). También se proporcionan registros adicionales de oviposición y depredación por especies de Harpactorini y Bactrodinae en ciertas plantas.Fil: Gil Santana, Helcio. Governo Do Estado Do Rio de Janeiro. Secretaria Da Saude. Instituto Vital Brasil.; BrasilFil: Keller, Hector Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentin

DIA: A complexity-effective decoding architecture

Fast instruction decoding is a true challenge for the design of CISC microprocessors implementing variable-length instructions. A well-known solution to overcome this problem is caching decoded instructions in a hardware buffer. Fetching already decoded instructions avoids the need for decoding them again, improving processor performance. However, introducing such special--purpose storage in the processor design involves an important increase in the fetch architecture complexity. In this paper, we propose a novel decoding architecture that reduces the fetch engine implementation cost. Instead of using a special-purpose hardware buffer, our proposal stores frequently decoded instructions in the memory hierarchy. The address where the decoded instructions are stored is kept in the branch prediction mechanism, enabling it to guide our decoding architecture. This makes it possible for the processor front end to fetch already decoded instructions from the memory instead of the original nondecoded instructions. Our results show that using our decoding architecture, a state-of-the-art superscalar processor achieves competitive performance improvements, while requiring less chip area and energy consumption in the fetch architecture than a hardware code caching mechanism.Peer ReviewedPostprint (published version

Método de estimación de la puntualidad en redes ferroviarias a través de la función densidad de probabilidad de los retrasos primarios

La presente herramienta surgió por la necesidad de pronosticar el retraso de un tren de mercancías. Era necesario cuantificar la influencia que tiene en el tiempo de transito de un convoy los distintos servicios que operan simultáneamente en la red ferroviaria. Se explican los mecanismos de propagación de los retrasos, explicando la diferencia entre retrasos primarios y retrasos secundarios; se hace una extensa descripción de método, donde se explicarán los datos que deben conocer el mismo y las salidas que podrá proporcionar; describirán una serie de aplicaciones de la metodología seguida y se muestran una serie de conclusiones

How efficient is city logistics? Estimating ecological footprints for urban freight deliveries

Es una ponencia de The Sixth International Conference on City Logistics, en Puerto Vallarta, México http://toc.proceedings.com/18996webtoc.pdfIn medium and large cities, the delivery of goods represents a significant contribution to the problems of congestion, lack of parking, pollution and energy consumption. The characteristics of this type of transport are also very different from passenger mobility, even though they are often assimilated, due to the lack of specific tools for estimation and analysis, and also of indicators to evaluate improvements in the systems of urban goods distribution. In this work, we start by developing a systematic model to estimate the transport of goods in a city, according to the particularities of its supply and demand. This model can then be used to determine with a high level of detail the contribution of the delivery of goods to the ecological footprint of the city, thus proposed as the key indicator of the efficiency of this type of transport. The work is applied to the city of Seville, in Spain.Spanish Ministry of Science and Technology DPI2008-0647