Abstract
This study seeks to assess the academic community's knowledge and perception of open innovation. While the so-called closed innovation is rooted in the discourse of future managers, open innovation, being a relatively recent paradigm, may be an unknown form of innovation and therefore its potential is underused. What is the perception of open innovation among students and faculty at a private Portuguese university? The technical procedure was based on a survey, and 64 responses were obtained (the population corresponds to 3666 people). It was shown that the theme of open innovation, despite being recognized in the academic world, is still little known in the community. Although Portugal is a country of meager funds for innovation, which should lead to a greater focus on open innovation, this may not be happening due to the lack of trust in strangers that exists culturally in Portugal, and that may be currently hindering open innovation partnerships. Finally, in order to identify possible relationships between gender and perceptions regarding open innovation, we applied the chi-square test of independence (X-2) in relation to gender. This exploratory study verified the existence of gender equality regarding the variables analyzed on open innovation.

Abstract
The emergence of the COVID-19 pandemic required swift adaptations within public spaces, particularly in view of the uncertainties enveloping the transmission dynamics of the virus. Among the prominently contacted surfaces, door handles have garnered significant attention in research efforts aiming to curtail transmission risks. A notable proposition emerged to obviate the necessity of direct physical contact with handles, thereby introducing a novel approach. Thus, the manufacturing modality of three-dimensional (3D) printing was naturally embraced, primarily attributable to its expeditious prototyping capabilities. Although the extant literature and the open-source community have proffered diverse panaceas, this inquiry embarked on rectifying certain inadequacies that had afflicted antecedent methodologies. Elaborate exposition is provided pertaining to the progression of the developmental trajectory and the concomitant design refinements. In a bid to substantiate the efficaciousness of the produced solution, the finite element analysis (FEA) was judiciously employed to assess two distinct loading scenarios: during the installation phase and the subsequent operation of the contrivance. The empirical findings manifest the commendable load tolerance, with the proposed solution being capable of withstand forces exceeding 15 N. Furthermore, even under the most adverse circumstances, the device evinced a maximal displacement of 15 mm. Collectively, the corollaries borne out of this scholarly investigation corroborate the efficacy, utilitarian functionality, and ergonomic viabilities of the proposed solutions and manufacturing process. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023.

Abstract

Abstract
Over the past few decades, road transportation emissions have increased. Vehicles are among the most significant sources of pollutants in urban areas. As such, several studies and public policies emerged to address the issue. Estimating greenhouse emissions and air quality over space and time is crucial for human health and mitigating climate change. In this study, we demonstrate that it is feasible to utilize raw GPS data to measure regional pollution levels. By applying feature engineering techniques and using a microscopic emissions model to calculate vehicle-specific power (VSP) and various specific pollutants, we identify areas with higher emission levels attributable to a fleet of taxis in Porto, Portugal. Additionally, we conduct network analysis to uncover correlations between emission levels and the structural characteristics of the transportation network. These findings can potentially identify emission clusters based on the network's connectivity and contribute to developing an emission inventory for an urban city like Porto.

Abstract
Entrepreneurial activity has been an element of economic and social enhancement. However, managing a startup is a difficult and risky activity that strongly depends on the entrepreneur's characteristics and skills. While much attention has been given recently to entrepreneurial learning, less has been studied about the learning dynamics in different industries. This study aims to understand and explore types of learning in different industries and find their similarities and differences. For this purpose, an exploratory comparative case study composed of four cases has been considered. Findings reveal that the main types of entrepreneurial learning are similar in all the industries analysed and are linked to social and experiential learning. The main dissimilarities are related to searching for customer information, employees' feedback, and solving issues. Lastly, some entrepreneurs reflect on the actions or decisions taken, while others do not reflect as much as they would like to. © 2023 Inderscience Enterprises Ltd.

Abstract
This paper presents an experimental investigation of sigma-delta modulation (SDM) as a means of improving the performance of underwater optical communication systems. The study considers the impact of the key parameters of SDM, including oversampling ratio, the system's signal-to-noise ratio, bandwidth, and optical link distance. The results of this study provide insights into the design and optimization of SDM-based underwater optical communication systems, paving the way for future research in this field. A fully digital solution, albeit operating at a lower bit rate than previously published OFDM counterparts, provides immunity against nonlinearities of the system and robustness to noise, which is relevant in harsh environments. Moreover, the proposed solution based on a first-order bandpass SDM architecture avoids the employment of a DAC at the receiver, simplifying its operation and reducing costs. An experimental investigation is carried out for the transmission of 16-QAM over SDM, and a transmission distance of 4.8 m over the underwater channel is achieved with a maximum transmission rate of 400 Mbit/s with an MER of 28 dB.