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• Case study on the transit network design and frequency setting problem. • Alternative lines plans are generated using a bi-objective memetic algorithm. • Realistic characteristics are incorporated in the model. • A large instance is proposed using real data, explaining the generation process. • The results are compared with the current situation using newly proposed metrics. This paper presents an approach to design better line plans for realistic cases. The planning problem is modelled as a realistic instance of the Transit Network Design and Frequency Setting Problem (TNDFSP). It incorporates additional assumptions taken from practice such as discrete frequencies, a subset of allowed terminal nodes and circular lines. A bi-objective memetic algorithm minimizes the average travel time (ATT) of the passengers and the fleet size. The method to generate the TNDFSP instance from real data is described in detail. Moreover, a new metric is proposed to compare different transit networks. In order to illustrate the approach, it is applied to the area of Utrecht, The Netherlands. The results show that the current network is modelled accurately and that the algorithm successfully generates alternative bus line plans within reasonable CPU time. It returns a subset of non-dominated solutions from which a compromise solution can be selected for practice. There are solutions with the same fleet size as the current solution, but a 6% lower ATT, or solutions with the same ATT, but a fleet size which is 19% smaller. Compared to the current network, the algorithm finds that it is convenient to substantially reduce the number of lines and to leave a small portion of demand unsatisfied. This paper also presents extensive experiments to test the impact of different assumptions about demand, bus capacity and minimum frequency. [ABSTRACT FROM AUTHOR]

In recent times, the emergence of coworking spaces (CSs) has changed not only the way workers cooperate, but also how they carry out their activities. This phenomenon, limited mainly to urban areas, has spread heterogeneously across cities. The paper focuses on the location of CSs in Barcelona, Warsaw and Utrecht, three European cities that differ in terms of the typology of creation of these workspaces. In the three analysed cities, CSs are mainly private initiatives, although in Barcelona they are developed by small entrepreneurs, while in Warsaw they are developed by large multinational CS chains. Using K-density (Kd) functions and density maps, we contribute to the empirical literature by identifying how CSs coagglomerate with the service sectors, how CSs are concentrated in core areas of each city and how these factors differ between cities, taking into account the typology of CSs. We found that the CS location and coagglomeration depend on the spatial structure of the city and its development model; therefore, policymakers should take this into account in order to implement appropriate policy measures to attract CSs • CSs agglomerate differently in cities with different levels of urban hierarchy and reveal different CSs location strategies. • The coagglomeration of CSs with Knowledge Intensive Services (KIS) and symbolic knowledge base firms has been confirmed. • Market and high tech KIS with CSs build an urban entrepreneurial ecosystem. [ABSTRACT FROM AUTHOR]

Transient clouds cause rapid changes in the power output of Photovoltaic (PV) solar systems. These ramp rates may lead to power quality problems, such as voltage fluctuations, in the low-voltage (LV) electricity grid. This paper firstly assesses the impact of a growing number of distributed PV systems on the voltage profile in a LV grid by considering PV penetration rates of 40%, 70% and 100% of the local rooftop capacity. Next, the potential of active power curtailment, grid reinforcement and supercapacitors to prevent or mitigate these voltage fluctuations are examined. The experiments in this study are based on simulations run with a two-second time resolution for an urban LV grid located in Utrecht, the Netherlands. This study identifies that problematic fluctuations occur already at a 40% PV penetration rate and are expected up to 7.4% of time for a 100% PV penetration scenario. Additionally, the local deployment of either active power curtailment or supercapacitors are identified as adequate strategies to regulate the occurring voltage fluctuations. Finally, the most stable voltage profile and the lowest number of problematic voltage fluctuations are found in case of adopting supercapacitors as part of the PV system. • An assessment of the impact of PV power output on the power quality in the low voltage grid. • A PV penetration of 40% will already cause problematic voltage fluctuations in the considered low voltage grid. • A numerical comparison among three different regulation strategies for mitigating rapid voltage fluctuations. • Grid reinforcement, active power curtailment and supercapacitors reduce the magnitude of voltage fluctuations. • Supercapacitors are most successful in mitigating problematic voltage fluctuations. [ABSTRACT FROM AUTHOR]