Activities of National Hellenic Documentation Centre and the National Network of Scientific and Technological Libraries

Περιέχει το πλήρες κείμενοThe mission of National (Hellenic) Documentation Centre (NDC)is to ensure the flow of the scientific and technological information to the Hellenic scientific community. This is achieved by establishing online access to 17 international hosts and 1.300 databases, acting as the major information intermediary in the country offering bibliographic references to 10.000 scientst per year, producing 8 national databases and hosting 40 databases produced by other national or international organisations. Concerning libraries NDC supports them by developing and disseminating ABEKT, the most popular library automation software in the country numbering more than 700 copies installed, developing, in close collaboration with 206 libraries, the Union Catalogue of Periodicals including 22.790 unique journal titles, creating and coordinating the National Network of Hellenic Scientific Libraries with 107 libraries supporting interlibrary loan through the online document ordering system provided by the host computer of NDC, developing its own digital library having access to more than 230 electronic journals via internet and about 1.000 installed locally, organising seminars, workshops and information days focusing on the electronic information services and technologies

Effects of countdown displays in public transport route choice under severe overcrowding

The paper presents a route choice model for dynamic assignment in congested, i.e. overcrowded, transit networks where it is assumed that passengers are supported with real-time information on carrier arrivals at stops. If the stop layout is such that passenger congestion results in First-In-First-Out (FIFO) queues, a new formulation is devised for calculating waiting times, total travel times and route splits. Numerical results for a simple example network show the effect of information on route choice when heavy congestion is observed. While the provision of information does not lead to a remarkable decrease in total travel time, with the exception of some particular instances, it changes the travel behaviour of passengers that seem to be more averse to queuing at later stages of their journey and, thus, prefer to interchange at less congested stations

Simulation of tourists' wayfinding during evacuation based on experiments in Kyoto

24th EURO Working Group on Transportation Meeting, EWGT 2021, 8-10 September 2021, Aveiro, PortugalTourists are often more vulnerable than residents in sudden disaster situations due to lack of knowledge regarding evacuation routes and safe areas. To establish protocols and the schemes for tourist evacuation to safe areas, it is necessary to gather their likely behavior during an evacuation. Since there are few actual data available we conducted a VR (Virtual Reality) experiment assuming a sudden disaster situation and estimated tourists’ route choice based on the experiment. In the experiment pictures of intersection in the touristic Higashiyama area of Kyoto, Japan, where shown to participants and they could choose the direction they want to proceed until reaching an open space or designated shelter. As a result, we could quantify the impact of road width and, to some degree, network structure. The results reveal the tendency to select wide roads and to proceed straight. If the participants were put under time pressure these tendencies are intensified. Utilizing these results we constructed an evacuation simulation. We estimated the distribution and amount of tourists using data obtained from a mobile phone service provider. We conducted the simulation using VisWalk with various guidance situations and compared those results. The results illustrate potential capacity bottlenecks of designated shelter locations and the importance to provide route guidance and certain points in the network

A model of bus bunching under reliability-based passenger arrival patterns

If bus service departure times are not completely unknown to the passengers, non-uniform passenger arrival patterns can be expected. We propose that passengers decide their arrival time at stops based on a continuous logit model that considers the risk of missing services. Expected passenger waiting times are derived in a bus system that allows also for overtaking between bus services. We then propose an algorithm to derive the dwell time of subsequent buses serving a stop in order to illustrate when bus bunching might occur. We show that non-uniform arrival patterns can significantly influence the bus bunching process. With case studies we find that, even without exogenous delay, bunching can arise when the boarding rate is insufficient given the level of overall demand. Further, in case of exogenous delay, non-uniform arrivals can either worsen or improve the bunching conditions, depending on the level of delay. We conclude that therefore such effects should be considered when service control measures are discussed

N-3 PUFA Supplementation Triggers PPAR-α Activation and PPAR-α/NF-κB Interaction: Anti-Inflammatory Implications in Liver Ischemia-Reperfusion Injury

Dietary supplementation with the n-3 polyunsaturated fatty acids (n-3 PUFA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) to rats preconditions the liver against ischemia-reperfusion (IR) injury, with reduction of the enhanced nuclear factor-κB (NF-κB) functionality occurring in the early phase of IR injury, and recovery of IR-induced pro-inflammatory cytokine response. The aim of the present study was to test the hypothesis that liver preconditioning by n-3 PUFA is exerted through peroxisone proliferator-activated receptor α (PPAR-α) activation and interference with NF-κB activation. For this purpose we evaluated the formation of PPAR-α/NF-κBp65 complexes in relation to changes in PPAR-α activation, IκB-α phosphorylation and serum levels and expression of interleukin (IL)-1β and tumor necrosis factor (TNF)-α in a model of hepatic IR-injury (1 h of ischemia and 20 h of reperfusion) or sham laparotomy (controls) in male Sprague Dawley rats. Animals were previously supplemented for 7 days with encapsulated fish oil (General Nutrition Corp., Pittsburg, PA) or isovolumetric amounts of saline (controls). Normalization of IR-altered parameters of liver injury (serum transaminases and liver morphology) was achieved by dietary n-3 PUFA supplementation. EPA and DHA suppression of the early IR-induced NF-κB activation was paralleled by generation of PPAR-α/NF-κBp65 complexes, in concomitance with normalization of the IR-induced IκB-α phosphorylation. PPAR-α activation by n-3 PUFA was evidenced by enhancement in the expression of the PPAR-α-regulated Acyl-CoA oxidase (Acox) and Carnitine-Palmitoyl-CoA transferase I (CPT-I) genes. Consistent with these findings, normalization of IR-induced expression and serum levels of NF-κB-controlled cytokines IL-lβ and TNF-α was observed at 20 h of reperfusion. Taken together, these findings point to an antagonistic effect of PPAR-α on NF-κB-controlled transcription of pro-inflammatory mediators. This effect is associated with the formation of PPAR-α/NF-κBp65 complexes and enhanced cytosolic IκB-α stability, as major preconditioning mechanisms induced by n-3 PUFA supplementation against IR liver injury

Dynamic process model of mass effects on travel demand

Whereas transportation planners commonly predict the negative impacts of mass transportation, there is increasing empirical evidence of the existence of positive mass effects, whereby increased use of a mode by the 'mass' will generally increase its attractiveness for future travellers. In this paper we consider the dynamic impact of such an effect on the problem of travel demand forecasting, with particular regards to social network effects. Our proposed modelling approach is inspired by literature from social physics, evolutionary game theory and marketing. For simplicity of exposition, our model is specified for a scenario in which (a) there is a binary choice between two mobility lifestyles, referred to as car-oriented and transit-oriented, and (b) there are two population groups, where one is the "leading" or "innovative" population group and the other the "following" or "imitating" population group. This latter distinction follows the rather well-known Bass model from the marketing literature (1969). We develop the transition probabilities and transition dynamics. We illustrate with a numerical case study that despite lower intrinsic utility for the transit lifestyle, significant changes towards this lifestyle can be achieved by considering congestion, service improvements and mass effects. We further illustrate that mass effects can be positive or negative. In all cases we explore the sensitivity of our conclusions to the assumed parameter values

Traffic Control: Current Systems and Future Vision of Cities

This paper summarises the results from a questionnaire-based survey and follow-up discussions with traffic operations staff of various cities in the world. The questionnaire asked cities about their currently employed control systems as well as about their organization's vision for the future. Data collected include details on traffic management techniques employed, if network monitoring is carried out and if yes, how, as well as about details on the traffic control centre itself. Efforts were further made to collect data on the city background such as population density, modal share and traffic safety which forms the basis to understand why particular solutions were chosen. The answers demonstrate some issues with definitions which are believed to exist not just in our data set but in many of the commonly referred to statistics. The results further show differences between cities as well as common issues and problems that need innovative solutions in the future for sustainable transportation policies. As several cities are currently in the process of defining longer-term strategic plans with similar goals the paper proposes that development of comparable evaluation measures helps municipal traffic managers to better select between available technical solutions. © 2010 Springer Science+Business Media, LLC