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- Explanatory Factors of the Capital StructurePublication . Silva, Marta; Gomes, Luís; Lopes, Isabel CristinaThis paper presents an empirical study of the capital structure of Portuguese companies where the main objective is to find key explanatory factors for indebtedness decisions. The relations between indebtedness and its determinants are tested in the light of the Trade-Off Theory and the Pecking-Order Theory. The motivation of this work was to contribute to the scientific research on the influential determinants of the capital structure and to deepen the knowledge of the Portuguese market. The quantitative methodology is used, through an econometric model for panel data using accounting information of 55 Portuguese companies between 2014 and 2016. Statistical tests such as the F test, the Lagrange Multiplier Breusch-Pagan test and the Hausman test were used to identify the most appropriate method of estimation, which resulted in a panel data model with random effects for individuals. The findings of this study suggest that indebtedness have a positive relation with tangibility and the size of the company, which supports the Trade-Off Theory. However, the positive relationship with the non-debt tax benefits suggests the importance of taxes, contrary to Trade-Off Theory. The negative relationship with cash flows, coupled with the positive relationships between size and growth opportunities, suggest the use of funding only when internal funds become insufficient, supporting the Pecking-Order Theory. The general results support that both theories partially explain the financing decisions of Portuguese companies.
- Seminar: Professional Skills Of The Graduates In Library And Information Sciences And Technologies From The Point Of View Of The Potential Employers, Students And ProfessorsPublication . Carvalho, Milena; Martins, Susana; Lopes, Isabel CristinaObjectives - In this paper we assess the perceptions of three different groups linked to Library and Information Science and Technology (LIST) degree (students, teachers and employers) regarding four dimensions and it is based on the assumption that the alignment of these perceptions may enhance the employability of LIST graduates
- Sectorization of a Parcel Delivery ServicePublication . Mostardinha, Mafalda; Escobar Hernández, Pablo; Lopes, Isabel Cristina; Rodrigues, Ana MariaThis paper explores the problem of sectorization of a parcel delivery service that wants to assign an action region to each of its teams, regarding the number of deliveries scheduled for each zone, so that there is a balanced service amongst sectors, covering contiguous zones, and considering limited capacities for the teams. Besides being relatively easy to model, the available optimization tools and software provide poor results when dimension increases in these types of problems, with computational capacity exceeding. In this paper an integer programming model, combined with an heuristic to return a faster solution, was implemented to solve a sectorization problem in two different situations. The main advantage of the strategy proposed, compared to previous ones, is its simplicity and easy implementation while still returning an optimal solution.
- An Application of Preference-Inspired Co-Evolutionary Algorithm to SectorizationPublication . Ozturk, E. Goksu; Rocha, Pedro; Sousa, Filipe; Lima, Maria Margarida; Rodrigues, Ana Maria; Soeiro Ferreira, José; Catarina Nunes, Ana; Lopes, Isabel Cristina; Oliveira, CristinaSectorization problems have significant challenges arising from the many objectives that must be optimised simultaneously. Several methods exist to deal with these many-objective optimisation problems, but each has its limitations. This paper analyses an application of Preference Inspired Co-Evolutionary Algorithms, with goal vectors (PICEA-g) to sectorization problems. The method is tested on instances of different size difficulty levels and various configurations for mutation rate and population number. The main purpose is to find the best configuration for PICEA-g to solve sectorization problems. Performancemetrics are used to evaluate these configurations regarding the solutions’ spread, convergence, and diversity in the solution space. Several test trials showed that big and medium-sized instances perform better with low mutation rates and large population sizes. The opposite is valid for the small size instances.
- A resectorization of fire brigades in the north of PortugalPublication . Lima, Maria Margarida; Ozturk, E. Goksu; Sousa, FIlipe; Lopes, Isabel Cristina; Teles Oliveira, Cristina; Rodrigues, Ana Maria; Catarina Nunes, Ana; Soeiro Ferreira, JoséSectorization can be regarded as a division of a territory into smaller regions to deal with a complex problem involving multiple-criteria. Resectorization intends to achieve another sectorization, according to some new conditions but avoiding substantial changes. An example of this can be the distribution of geographical areas by fire brigades. In Portugal, fire brigades must protect and rescue the population in the areas surrounding their fire stations. So we will use the current sectorization, the geographic and population characteristics of the areas and the fire brigades’ response capacity to provide an optimised resectorization, in order to decrease rescue time. To achieve that, we will use a decision support system using different optimisation methods, such as Non-dominated Sorting Genetic Algorithm (NSGA II), which provides an effective sectorization concerning compactness and equilibrium criteria.
- Sectorization for managing maintenance techniciansPublication . Lopes, Isabel Cristina; Rodrigues, Ana Maria; Oliveira, Cristina; Soeiro Ferreira, José; Cortinhal, Maria Joãobetter organization of the region, or to simplify a large problem into smaller sub-problems, or to obtain groups with similar characteristics. To evaluate the quality of the solutions, three criteria are commonly used: Equilibrium (the sectors should be identical portions of the whole), Compactness (regular forms like circles are preferred, avoiding sectors shaped with ‘tentacles’), and Contiguity (avoid sectors divided into portions). Depending on the application, other criteria can also be considered, therefore multicriteria approaches should be used. Sectorization problems can arise when designing political districts, defining sales territories, managing routes for distribution of goods or collecting municipal waste, assigning neighborhoods to schools, locating health care services, police stations, or fire brigades. This talk will address the sectorization in an elevator maintenance company, where the definition of the zones assigned to each technician have an impact on the company’s efficiency and quality of service. In order to define the best sectorization, not only the maintenance plan should be considered, but also the unplanned interventions. We will discuss the different solution methods that can be applied to this case.
- Perceptions of the skills of graduates in the library and information science and technology degree of P. Porto, Portugal: A Statistical Data Analysis of the Alignment Between Students, Teachers, and EmployersPublication . Martins, Susana; Lopes, Isabel Cristina; Carvalho, MilenaObjective – The objective of this research was to identify the four professional competences of graduates in Library and Information Sciences and Technologies (LIST) considered most pertinent, from the points of view of students, teachers, and employers. We also sought to compare the perceptions of the different groups. The study was based on the premise that alignment of these perceptions may enhance the employability of LIST graduates. Methods – A questionnaire, used and validated by Arias-Coello et al. (2014), was further translated by Martins and Carvalho (2018). The questionnaire consisted of a set of questions regarding four dimensions: Information Management; Communication and Interpersonal Relationships; Domain and Application of Information Technologies; Organization Management. We sent the survey by email to the target audience; it was available to complete in April and May 2018. Data analysis included calculating mean and standard deviation, as well as Shapiro Wilk normality tests, statistical tests for multiple comparisons, ANOVA, Kruskal Wallis test, Friedman test, Wilcoxon test, and Pearson's correlation. Results – In relation to certain dimensions, one could think that age would be a determining factor, but this has not been proved. In fact, results showed that age is not a factor that influenced the importance attributed to different competences in the several dimensions. The respondents' academic degrees and areas of knowledge were linked to significant differences transversally. The Kruskal Wallis test indicated that students, teachers, and employers perceived the importance of Information and Communication Technologies (ICT) skills equally. As for the other competences, overall there were significant differences between students and employers, and there were significant differences between students and teachers regarding the perceived importance of organization management skills. There were also significant differences between teachers, students, and employers regarding the perceived importance of communication skills. We also found that responses within the teacher group had less dispersion of answers, therefore there was greater internal agreement. The opposite occurred in the employer group. Conclusion – The differences detected in the perception of the different groups were minor. However, it is necessary to create initiatives for the alignment of the perceptions of students and employers, because if all groups have the same perception, they will develop and value the same skills, responding to the needs of the labor market, thus promoting the employability of LIST graduates. The inclusion of a curricular internship, even one of short duration, in the first year of the degree could also be a way of endeavoring to bring together the expectations of both groups. These suggestions are part of a proposal to change and update the study plan and enhance the performance of course management.
- Creating interactive learning materials to promote statistical skills in higher educationPublication . Paula Lopes, Ana; Baptista Soares, Filomena; Teles Oliveira, Cristina; Rodrigues, Ana Maria; Torres, Cristina; Lopes, CristinaNovas oportunidades de aprendizagem ao longo da vida, currículos alternativos no ensino pré-universitário e políticas bastante “abertas” de acesso ao Ensino Superior (ES) têm potenciado, nas últimas décadas, o problema da falta de homogeneização de saberes e competências dos alunos “calouros” em Instituições de Ensino Superior (IES). Este problema torna-se avassalador quando se trata de unidades curriculares básicas "construtivas", como a Matemática ou a Estatística, em licenciaturas não matemáticas, em áreas como a Administração, Contabilidade ou Gestão. Esta é uma “luta” diária que os docentes destas unidades curriculares enfrentam ao tentarem falar de disciplinas mais avançadas a um público muito heterogéneo, com diferenças significativas na formação matemática, promovendo a participação de todos os alunos e evitando o abandono precoce de alguns . Neste sentido, Neste artigo serão apresentadas algumas dessas estratégias, desenvolvidas no Politécnico do Porto (P.PORTO) e baseadas na criação e utilidade dos materiais interativos de ensino e aprendizagem. Sentiu-se a real necessidade de inovar no processo de ensino-aprendizagem e a procura de um bom software de apoio, que permitisse desenvolver todos os materiais e implementar interações reais, culminou com a escolha do iSpring Suite 9. Este software é um poderoso kit de ferramentas de eLearning para PowerPoint que permite desenvolver cursos, videoaulas e avaliações de qualidade que funcionarão em qualquer desktop, laptop e plataforma móvel. Portanto, o uso do iSpring Suite 9 será descrito...
- A Mathematical Model for Supermarket Order PickingPublication . Costa e Silva, Eliana; Cruz, Manuel; Lopes, Isabel Cristina; Moura, AnaOrder picking consists in retrieving products from storage locations to sat- isfy independent orders from multiple customers. It is generally recognized as one of the most significant activities in a warehouse (Koster et al, 2007). In fact, order picking accounts up to 50% (Frazelle, 2001) or even 80% (Van den Berg, 1999) of the total warehouse operating costs. The critical issue in today’s business environ- ment is to simultaneously reduce the cost and increase the speed of order picking. In this paper, we address the order picking process in one of the Portuguese largest companies in the grocery business. This problem was proposed at the 92nd European Study Group with Industry (ESGI92). In this setting, each operator steers a trolley on the shop floor in order to select items for multiple customers. The objective is to improve their grocery e-commerce and bring it up to the level of the best inter- national practices. In particular, the company wants to improve the routing tasks in order to decrease distances. For this purpose, a mathematical model for a faster open shop picking was developed. In this paper, we describe the problem, our proposed solution as well as some preliminary results and conclusions.
- The Relationship of the Human Capital Index with the Level of Education and the Adult Survival RatePublication . Marques, Alexandra; Pinheiro, Ana; Matos, Maria Carolina; Torres, Cristina; Lopes, Isabel Cristina; Vieira, IsabelThe relationship between the level of education and the adult survival rate with the human capital index and its components is studied using cluster analysis, applied to a sample of 174 countries covering all continents. The results allow the grouping of countries into three clusters that are consistent with three different levels of development. It was also observed that the lower the values of survival rate and level of education, the lower the human capital index of a country is.