Centralised architecture models are often adopted in the development of smart cities to take advantage of the technologies provided by dominant companies such as Google, Meta, and Amazon. This approach often comes with significant drawbacks, such as (i) application developers becoming dependent on the policies and rules imposed by large companies, which are subject to change, and (ii) users having their data collected and used haphazardly, and often without authorisation, which can undermine the trust that users place in the solution. Infrastructure for smart cities should, therefore, incorporate decentralised technologies that satisfy or reinforce important quality attributes such as trustworthiness, privacy, and security. The main objective of this article is to survey and discuss how the services of a smart city can be implemented using decentralised architectures; we explain the advantages and disadvantages of decentralised architectures and emerging technologies. We review the specialised literature and compile a set of emerging technologies that are essential to conceive a decentralised architectural solution for smart cities. The current state-of-the-art in decentralisation shows that this model can be implemented with current technologies and help to satisfy the quality attributes mentioned above, and potentially reinforce the degree of trustworthiness of the solution. We also propose a four-dimension guideline that functions as a conceptual driver for structuring actions for researchers, system architects, policymakers, and city authorities in the design, evaluation, and long-term maintenance of decentralised smart cities, thereby enhancing their capacity to address escalating urban challenges. We conclude that the set of technologies discussed in this article has the potential to be reused and replicated across smart cities. • Choice between C-architecture and D-architecture for smart cities. • Concerns about interoperability, privacy, vendor lock-in, and sustainability. • Decentralisation offers improved interoperability, privacy, and sustainability. • Approach to decentralised digital identity, permissions, and integration solutions.

Search-Based Software Engineering (SBSE) is widely used in different fields of Software Engineering, notoriously, in Enterprise Application Integrations (EAIs). EAI encompasses methodologies, techniques and tools that a software engineer can use to create integration solutions. SBSE is currently an active research topic of increasing interest. The number and diversity of publications produced yearly are large to the extent that it is hard to identify the active research groups, their locations, techniques used and research topics that have not received enough attention. To answer these questions categorically, we have conducted systematic mapping study of the literature. In this paper, we report our methodology and findings. In our study, we used systematic search strategies that resulted in the retrieval of 560 articles, of which we first selected 25. Second, on the basis of the authors’ experience, we included eight additional articles. Finally, we used a snowballing sample technique to include another 12 articles. The results demonstrate that during the last two decades (1999–2020) EAI has benefited from the use of Search-Based Software Engineering techniques.

Summary Increasingly enterprises rely on software applications to support their business processes. Since such processes are continually evolving to keep up with market dynamism, companies strive to increase their efficiency, for example, by optimising the integration of applications supporting these processes. Integration platforms are specialised software tools that allow creating integration processes so that applications can share data and functionality. However, this integration involves several challenges, especially when large volumes of heterogeneous data should be integrated and shared. The performance of an integration process, in terms of message processing, is directly related to the run‐time system of the integration platform. This article investigates the impact of the volume of messages and the number of threads used by a run‐time system on makespan and performance of an integration process. The greater is the number of messages per second received by the integration process, the high is the volume of messages. The study was based on a run‐time system with task‐based execution model and follows a strict protocol to conduct and report our empirical study. We observed an increment of makespan when increasing the volume of messages to integration processes and different behaviours when increasing the number of threads used in their executions. Makespan reduces as the number of threads increases, but only when the volume of inbound messages is not very high. We confirmed that there is a performance gain by increasing the number of threads to execute an integration process, but observed that the continuous increment of threads leads to degradation of the performance in this model.

Summary Companies are taking advantage of cloud computing to upgrade their business processes. Cloud computing requires interaction with many kinds of applications, so it is necessary to improve the performance of software tools that allow keeping information on all these applications consistent and synchronised. Integration platforms are specialised software tools that provide support to design, implement, run, and monitor integration solutions, which aim to orchestrate a set of applications so as to promote compatibility among their data or to develop new functionality on top of the current ones. The run‐time system is the part of the integration platform responsible for running the integration solutions, which makes its performance the uttermost important issue. The contribution of this article is two‐fold: a framework and an evaluation of integration platforms. The former is a framework composed of ten properties grouped into two dimensions to evaluate the run‐time systems focusing on performance. Using this framework as reference, the second contribution is an evaluation of nine open‐source integration platforms, which represent the state‐of‐the‐art, provide support to the integration patterns, and follow the pipes‐and‐filters architectural style. In addition, as a result of this work, we suggest open research directions that can be explored to improve the performance of the run‐time systems and at the same time may be useful to adapt them to the context of cloud computing.

In this paper we discuss the migration of a 2D netlist with pre-placed I/Os to 3D circuits. For that, we present an algorithm to perform the partitioning of the I/O pins into various tiers targeting at I/O balancing and 3D-vias minimization. We formulate the netlist migration constrained with respect to the preservation of some original netlist properties. The I/O partitioning algorithm is based on the logic distance between I/Os. Since there is no literature on I/O partitioning for 3D circuits we compared our algorithm with two simplistic approaches that targeted balance and min-cut respectively. Experimental results show that our algorithm can reduce the number of 3D-vias compared to both algorithms, while balance is kept close to optimal. Most importantly, we showed that performing I/O partitioning separately we can reduce the number of 3D-vias even more than existing solutions in the literature for the netlist partitioning. Additionally, we studied the area impact of the 3D-vias resulted from the three algorithms targeting two different technologies for 3D circuits. We observed that especially in the bulk based technologies the 3D-via penalty is huge, favoring our algorithm