728 research outputs found
Potential demand and cost-benefit analysis of electric cars
In this study an analysis of electric family car performances is carried out. In particular, the aim of this
research is to appraise the possibility of introducing electric cars in urban mobility and the evaluation of
its economic feasibility. First of all, we determined the potential electric car demand, which was
forecasted using a stated preference (SP) analysis. The survey was carried out at the University of
Palermo considering a particular target of consumer: “the hybrid household”. A logit demand model was
calibrated using the SP technique to model the choice between the electric car and the conventional one.
In the second part of the work, the economic feasibility of the electric car is analysed by comparing the
operating cost per kilometre of the internal combustion car with that of the electric one. Two options were
analysed for electric cars: car purchase and car sharing
Bus speed estimation by neural networks to improve the automatic fleet management
In the urban areas, public transport service interacts with the private mobility. Moreover, on each link
of the urban public transport network, the bus speed is affected by a high variability over time. It depends
on the congestion level and the presence of bus way or no. The scheduling reliability of the public
transport service is crucial to increase attractiveness against private car use. A comparison between a
Radial Basis Function network (RBF) and Multi layer Perceptron (MLP) was carried out to estimate the
average speed, analysing the dynamic bus location data achieved by an AVMS (Automatic Vehicle
Monitoring System). Collected data concern bus location, geometrical parameters and traffic conditions.
Public Transport Company of Palermo provided these data
Modelling Airlines Competition on Fares and Frequencies of Service by Bi-level Optimization
AbstractThe research aims to understand how airlines make operative decisions on fares and frequencies of service in a competitive envi-ronment. A game approach has been developed to model the airlines’ choices in a duopolistic market. In particular, the short haul market for intercity linkages has been investigated. In this segment the air mode is in competition with other ground modes (i.e. road and high speed rail). A bi-level optimization program has been realized. The variables of model are: fares and frequencies of airlines
Transport policy and climate change: how to decide when experts disagree
Transport is the sector with the fastest growth of greenhouse gases emissions in many countries. Accumulation of these emissions may cause uncertain and irreversible adverse climate change impacts. In this context, we use the analytic hierarchy process (AHP) to face the question on how to select the best transport policy if the experts have different opinions and beliefs on the occurrence of these impacts. Thus, both the treatment of uncertainty and dissent are examined for the ranking of transport policies. The opinions of experts have been investigated by a means of a survey questionnaire. A sensitivity analysis of the experts’ weights and the criteria’ weights confirms the robustness of the results
SYRPHIDAE (DIPTERA) FROM LAMPEDUSA ISLAND
Diptera of Lampedusa are poorly known, and the only published data are those of VENTURI
(1960) and PISCIOTTA et al. (2008). In the present paper the authors report new records of Syrphidae (Diptera) for Lampedusa island discovered during field investigations carried out for a broader research project in the island. Data are updated to November 2009. Eleven species of Syrphidae new for Lampedusa have been found of which one is new for the Sicilian fauna
Modelling strategic alliances in the wide-body long range aircraft market
The wide-body long-range aircrafts market is characterized by increasing rivalry between Airbus and Boeing. One of the factors that drive their strategic behaviour is technological. We propose a technology indicator to identify conditions under which the aircraft companies have incentives to join a coalition. For this, we provide measurement of the side-payments necessary to sign a strategic alliance aimed at reducing technological barriers in the market. The results suggest that the existence of side-payments guarantees the stability of a strategic alliance if the gap in the technological level between the firms is high, or competition is through prices. For monopoly, a strategic alliance is profitable, but never stable
Multistep, sequential control of the trafficking and function of the multiple sulfatase deficiency gene product, SUMF1 by PDI, ERGIC-53 and ERp44.
Sulfatase modifying factor 1 (SUMF1) encodes for the formylglicine generating enzyme, which activates sulfatases by modifying a key cysteine residue within their catalytic domains. SUMF1 is mutated in patients affected by multiple sulfatase deficiency, a rare recessive disorder in which all sulfatase activities are impaired. Despite the absence of canonical retention/retrieval signals, SUMF1 is largely retained in the endoplasmic reticulum (ER), where it exerts its enzymatic activity on nascent sulfatases. Part of SUMF1 is secreted and paracrinally taken up by distant cells. Here we show that SUMF1 interacts with protein disulfide isomerase (PDI) and ERp44, two thioredoxin family members residing in the early secretory pathway, and with ERGIC-53, a lectin that shuttles between the ER and the Golgi. Functional assays reveal that these interactions are crucial for controlling SUMF1 traffic and function. PDI couples SUMF1 retention and activation in the ER. ERGIC-53 and ERp44 act downstream, favoring SUMF1 export from and retrieval to the ER, respectively. Silencing ERGIC-53 causes proteasomal degradation of SUMF1, while down-regulating ERp44 promotes its secretion. When over-expressed, each of three interactors favors intracellular accumulation. Our results reveal a multistep control of SUMF1 trafficking, with sequential interactions dynamically determining ER localization, activity and secretion
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