Modeling different penetration rates of eco-driving in urban areas: Impacts on traffic flow and emissions

Climate change and air quality are two main environmental challenges in metropolitan areas. As road transportation is one of the main contributors, public administrations are facing these problems with a number of complementary policy measures: shift to cleaner modes, new fuels and vehicle technologies, demand management, and the use of information and communication technologies (ICT) applied to transportation. Eco-driving is one of the measures that present large fuel savings at individual level. Although these savings are well documented in the literature, few studies focus on how eco-drivers driving patterns affect the surrounding vehicles and the traffic in general, and more particularly what would be the impact when the number of eco-drivers grows. Using a traffic microsimulation tool, four models in urban context have been built, corresponding to the different types of urban roads. Both the base-case and the parameters setting to simulate eco-driving have been calibrated with real data collected through floating vehicles performing the trips with normal and eco behaviors. In total, 72 scenarios were simulated, varying the type of road, traffic demand, and the percentage of eco-drivers. Then, the CO₂ and NO_x emissions have been estimated through a microscopic emission model. The results show that in scenarios with low or medium demand levels and increasing number of eco-drivers, the effects are positive in terms of emissions. On the other side, with high percentage of eco-drivers and high traffic demand, the emissions rise. Higher headways and smooth acceleration and decelerations increase congestion, producing higher emissions globally.     

Exact and approximated calculation of the cycle service level in a continuous review policy

The paper proposes a method to compute the exact cycle service level for (s, Q) continuous review policy in the presence of undershoots and discrete demand in the discrete time domain. Prior to this, it is necessary to review the definition of the cycle service level in order to avoid the problems that can be found when applied it to the periodic review policy. Therefore, the aim of this paper is: (a) to review the definitions of the cycle service level when applied to continuous review policies; (b) to develop an exact calculation method of the CSL for a continuous review policy when undershoots are allowed and demand is discrete; and (c) to examine some common believes about the cycle service properties. Finally, the bias obtained when the service cycle level is estimated applying the common assumption of neglecting undershoots at the order point is illustrated with some numerical examples which show that it may lead to significant deviations to be ignored.     

Exact and approximate calculation of the cycle service level in periodic review inventory policies

The parameters of stock policies are usually determined to minimize costs while satisfying a target service level. In a periodic review policy the time between reviews can be selected to minimize costs while the order-up-to-level is based on the fulfilment of a target service level. Generally, the calculation of this service measurement is obtained using approximations based on an additional hypothesis related to the demand pattern. Previous research has shown that there is a substantial difference between exact and approximate calculations in some general circumstances, so in these cases the service level is not accomplished or the stock level is overestimated. Although an exact calculation of CSL was developed in previous work, the computational effort required to apply it in practical environments leads to the proposal of two approximate methods (PI and PII) that, with the classic approximation, are analysed and evaluated in this paper. This analysis points out the risks of using the classic approximation and leads one to suggest PII as the most suitable and accurate enough procedure to compute the CSL straightforwardly in practice. Additionally, a heuristic approach based on PII is proposed to accept or reject an inventory policy in terms of fulfilling a given target CSL. This paper focuses on uncorrelated, discrete and stationary demand with a known distribution pattern and without backlog.     

The nature of entrepreneurial experience,business failure and comparative optimism

Entrepreneurial (i.e. business ownership) experience may enable some entrepreneurs to temper their comparative optimism in subsequent ventures. The nature of entrepreneurial experience can shape how entrepreneurs adapt. Using data from a representative survey of 576 entrepreneurs in Great Britain, we find that experience with business failure was associated with entrepreneurs who are less likely to report comparative optimism. Portfolio entrepreneurs are less likely to report comparative optimism following failure; however, sequential (also known as serial) entrepreneurs who have experienced failure do not appear to adjust their comparative optimism. Conclusions and implications for entrepreneurs and stakeholders are discussed.     

Multi-horizon inflation forecasts using disaggregated data

In this paper we use multi-horizon evaluation techniques to produce monthly inflation forecasts for up to twelve months ahead. The forecasts are based on individual seasonal time series models that consider both, deterministic and stochastic seasonality, and on disaggregated Consumer Price Index (CPI) data. After selecting the best forecasting model for each index, we compare the individual forecasts to forecasts produced using two methods that aggregate hierarchical time series, the bottom-up method and an optimal combination approach. Applying these techniques to 16 indices of the Mexican CPI, we find that the best forecasts for headline inflation are able to compete with those taken from surveys of experts.     

A note on external habits and efficiency in the AK model

This paper examines the implications for equilibrium efficiency of alternative formulations of habit formation in the AK model with external habits. Agent’s utility depends on how her current consumption compares to a reference consumption level—the habits stock—determined by average past consumption in the economy. We first prove that perfect substitutability between consumption and habits along the equilibrium path is necessary and sufficient for efficiency. Then, we prove that the competitive equilibrium is efficient if and only if habits enter utility in a subtractive form.     

Social responsibility and corporate reputation: The case of the Arthur Andersen Enron audit failure

We examine the influence of social responsibility ratings on market returns to Arthur Andersen (AA) clients following the Enron audit failure. Chaney and Philipich (2002) found that AA’s loss of reputation resulted in negative market returns to AA clients following the Enron audit failure. Proponents of social responsibility argue that social responsibility can improve the reputation of the firm, while detractors argue that social responsibility expenditures are a poor use of shareholder money. If social responsibility sends a signal to investors regarding the reputation/ethics of management, social responsibility could mitigate the negative returns to AA clients following the Enron audit failure. Using a matched sample of AA and non-AA firms, we do not find evidence that social responsibility mitigated the negative returns to AA clients following the Enron audit failure. Our results are inconsistent with claims that social responsibility can burnish a firm’s reputation in a time of crisis and with prior research indicating a positive relationship between social responsibility and market value.     

Empowered self‐development and continuous learning

Organizational changes are creating the need for continuous learning environments that support employees' self‐development. Self‐development means seeking and using feedback, setting development goals, engaging in developmental activities, and tracking progress on one's own. This assumes that people are capable not only of monitoring their own behaviors, but also of recognizing which behaviors and outcomes are most favorable and desirable. Drawing on self‐determination theory, this article shows how organizations can encourage self‐development by providing nonthreatening performance feedback, ensuring behavioral choices for learning, encouraging feedback seeking, and rewarding participation in learning activities and other self‐determined behavior. © 1999 John Wiley & Sons, Inc.     

Globales Preisabkommen: Ein Weg zu einer effektiven Klimapolitik?

This article outlines a potential route to an effective global climate protection agreement. It is argued that setting a globally uniform price for greenhouse gas emission abatement maximizes the chances for reaching such an effective agreement. Without an agreement on a globally uniform price, the Paris Treaty on limiting the increase in average temperatures to 2 degrees centigrade at most might fail. Germany should thus urge the other countries of the G20 Forum to agree on a common price on greenhouse gas emissions.     

Cultural Secrecy and Anti‐corruption Disclosure in Large Multinational Companies

This paper analyses the relation between countries’ cultural characteristics and anti‐corruption disclosure. In particular, it extends prior research and examines whether country‐level secrecy also appears to impact differences in this type of disclosure, while controlling for factors previously shown to matter. Using Transparency International ratings of disclosures on anti‐corruption efforts by large multinational firms and an ordinal regression analysis, the paper documents that companies from more ‘secretive’ countries have significantly lower levels of anti‐corruption disclosure.