Algorithm portfolios for logistics optimization considering stochastic demands and mobility allowance

The vehicle routing problem with stochastic demand (VRPSD) is a well known NP-hard problem. The uncharacteristic behaviour associated with the problem enhances the computational efforts required to obtain a feasible and near-optimal solution. This paper proposes an algorithm portfolio methodology based on evolutionary algorithms, which takes into account the stochastic nature of customer demand to solve this computationally complex problem. These problems are well known to have computationally complex objective functions, which make their solutions hard to find, particularly when problem instances of large dimensions are considered. Of particular importance in such situations is the timeliness of the solution. For example, Apple was forced to delay their shipments of iPads internationally due to unprecedented demand and issues with their delivery systems in Samsung Electronics and Seiko Epson. Such examples illustrate the importance of stochastic customer demands and the timing of delivery. Moreover, most of the evolutionary algorithms, known for providing computationally efficient solutions, are unable to always provide optimal or near optimal solutions to all the VRPSD instances within allocated time interval. This is due to the characteristic variations in the computational time taken by evolutionary algorithms for same or varying size of the VRPSD instances. Therefore, this paper presents portfolios of different evolutionary algorithms to reduce the computational time taken to resolve the VRPSD. Moreover, an innovative concept of the mobility allowance (MA) in landmoves based on the levy’s distribution function has been introduced to cope with real situations existing in vehicle routing problems. The proposed portfolio approach has been evaluated for the varying instances of the VRPSD. Four of the existing metaheuristics including Genetic Algorithm (GA), Simulated Annealing (SA), Artificial Immune System (AIS), TABU Search (TS) along with new neighbourhood search, are incorporated in the portfolios. Experiments have been performed on varying dimensions of the VRPSD instances to validate the different properties of the algorithm portfolio. An illustrative example is presented to show that the set of metaheuristics allocated to certain number of processors (i.e. algorithm portfolio) performed better than their individual metaheuristics.     

The Main Determinants of the Use of the Cost Accounting System in Portuguese Local Government

Abstract: This paper explores the main determinants of the use of the cost accounting system (CAS) in Portuguese local government (PLG). Regression analysis is used to study the fit of a model of accounting changes in PLG, focused on cost accounting systems oriented to activities and outputs. Based on survey data gathered from PLG, we have found that the use of information in decision‐making and external reporting is still a mirage. We obtain evidence about the influence of the internal organizational context (especially the lack of support and difficulties in the CAS implementation) in the use for internal purposes, while the institutional environment (like external pressures to implement the CAS) appears to be more deterministic of the external use. Results strengthen the function of external reporting to legitimate the organization's activities to external stakeholders. On the other hand, some control variables (like political competition, usefulness and experience) also evidence some explanatory power in the model. Some mixed results were found that appeal to further research in the future. Our empirical results contribute to understand the importance of interconnecting the contingency and institutional approaches to gain a clear picture of cost accounting changes in the public sector.     

Does local and Euro area sentiment matter for sovereign debt markets? Evidence from a bailout country

Does sentiment impact the sovereign debt markets? This article investigates whether lagged domestic and Euro area irrational sentiment (optimism or pessimism unwarranted by fundamentals) predicts future sovereign bond spreads, in Portugal, between January 2000 and December 2013. We find that domestic and Euro area sentiment negatively forecasts total return spreads and that this effect is stronger during the bailout period. Also, we find that the business sentiment is even most noticed. Therefore, Portuguese sovereign debt market is prone to the influence of investors’ sentiment.     

Understanding drivers and outcomes of lurking vs. posting engagement behaviours in social media-based brand communities

ABSTRACT

Social media-based brand communities (SMBBC) are ideal tools to develop Consumer Engagement (CE). Yet, brands do not fully understand whether members are really loyally engaged with the brand and uncertainties remain regarding SMBBC return on investment. Therefore, our aim is to understand what drives CE within SMBBC, to relate it to different CE behaviours and to study its impact on brand loyalty. Data from 213 Facebook users was analysed using PLS-SEM. The study concludes that the drivers for passive/lurking and active/posting behaviours differ and vary according to brand type, with the former revealing a stronger positive association with brand loyalty than the latter. This study also provides valuable insights into CE literature and to brands holding SMBBC, helping them to successfully develop social media strategies.     

Trends and Paths From Border Regions＂ The Frontier Centro-Castilla y Leon of Portugal and Spain

The objective of this paper is to determine whether the process of European Union （EU） integration has unleashed a new territorial dynamic with the convergence of border regions. Authors intend to analyze trends and trajectories of the Portuguese--Spanish border regions of the Center of Portugal and Castilla y Leon, particularly the municipalities of NUTS Ill and northern and southern Beira Interior （Central Region） and the provinces of the municipalities of Salamanca and Zamora （Region of Castilla y Leon）, in the last 20 years, given a set of demographic, economic, and social indicators, by using statistical analysis combined with contributions from the development processes established in these regions.     

Diffusion of multi-generational high-technology products

Previous multi-generational product diffusion (MGPD) models were developed based on the diffusion patterns at that time, but may not be adopted in today's cases. By incorporating the effect of customers' forward-looking behaviour, this paper offers a parsimonious and original model that captures the dynamics of MGPD in current high-technology markets. We empirically examine the feasibility of using previous MGPD models and our suggested model to explain the market growth of new products from high-technology industries. The results show that the new model exhibits better curve fitting and forecasting performance than the prior MGPD models in the cases of this study. For marketing researchers, our model and its results suggest customers' forward looking behaviour is perhaps one of the key sales affecting factors that are missing in previous MGPD models in explaining nowadays' cases. For marketing practitioners, this study offers a valuable tool for marketing strategies in high-tech industries.     

Air transport demand and economic growth in Brazil: A time series analysis

We investigate the relationship between air transport demand (passenger-kilometer: PAX) and economic growth (GDP) between 1966 and 2006 in Brazil. Special attention is paid to stationary features and the existence of a long-run equilibrium between variables to work in a vector autoregressive environment. Our findings suggest that GDP and PAX are co-integrated. Impulse-response analysis indicates a strong positive reaction of PAX due to a positive change in GDP. However, GDP reacts to a change in PAX in a slower and moderated way. We interpret these findings as an empirical evidence of air transport multiplier effects in the economy.     

The effect of a roundabout corridor's design on selecting the optimal crosswalk location: A multi-objective impact analysis

Crosswalks located at mid-block segment between roundabouts can provide a good balance among delay, carbon dioxide (CO₂) emissions, and relative difference between vehicles and pedestrians speed. However, when considering local pollutant criteria, the optimal crosswalk location may be different to that obtained for CO₂. This paper described a multi-objective analysis of pedestrian crosswalk locations, with the objectives of minimizing delay, emissions, and relative difference between vehicles and pedestrians speed. Accounting for the difference between global (e.g., CO₂) and local pollutants (monoxide carbon, nitrogen oxides, and hydrocarbons) was one the main considerations of this work. Vehicle activity along with traffic and pedestrian flows data at six roundabout corridors in Portugal, one in Spain, and one in the United States were collected and extracted. A simulation environment using VISSIM, Vehicle Specific Power, and Surrogate Safety Assessment Model models was used to evaluate traffic operations along the sites. The Fast Non-Dominated Sorting Genetic Algorithm (NSGA-II) was implemented to further search optimal crosswalk locations. The results yielded improvements to both delay and emissions by using site-optimized crosswalks. The findings also revealed that the spacing between intersections widely influenced the optimal crosswalk location along a mid-block section. If the spacing is low (<100 m), the crosswalk location will be approximately in 20%–30% of the spacing length. For spacing values between 140 and 200 m, crosswalks would be located at the midway position. When a specific pollutant criterion was considered, no significant differences were observed among optimal crosswalk data sets.     

Are electronic government innovations helpful to deter corruption? Evidence from across the world

Electronic government innovations have been a critical development in public administration in recent years. Many countries have implemented e-government policies to enhance efficiency and transparency and combat corruption. This paper examines the impact of e-government on corruption using longitudinal data for more than 170 countries from 2002 to 2020. The empirical results suggest that e-government serves as a deterrent to corrupt activities. We analyse which e-government domains affect corruption, which types of corruption are more affected by e-government and the circumstances under which e-government is more effective in reducing corruption. The empirical results suggest that online service completion and e-participation are important features of e-government as an anticorruption tool. Evidence suggests that e-participation reduces corrupt legislature activities, public sector theft, executive bribery, and corrupt exchanges. The potential of e-government to deter corruption is higher in countries where corruption is moderate or high and economic development is lower. Higher levels of GDP per capita, foreign direct investment, and political rights are also associated with lower levels of corruption.