2021
Autores
Zhang, C; Moreira, MRA; Sousa, PSA;
Publicação
TOTAL QUALITY MANAGEMENT & BUSINESS EXCELLENCE
Abstract
This research aims to highlight the major domains of and address the most prominent topics in the Total Quality Management (TQM) field in the service sector. Although there are numerous studies related to TQM, systematic quantitative reviews on TQM in services are scarce. The objective of this paper is to present a thorough analysis of the current mostly discussed issues related to the use of TQM in services by conducting a bibliometric analysis of the extant literature on TQM collected from Web of Science and Scopus databases. The findings indicate that TQM implementation is not a fading topic. The studies in the field of 'TQM use in services' are growing and becoming more intensive. TQM-related practices are gaining more attention while the TQM implementation framework is still under development. Healthcare is the most researched industry. Top management commitment/leadership is a critical construct and managers should be aware of the obstacle caused by lacking it. TQM professionals and managers in the service sector can benefit from this paper by having a sketch of the latest and most prominent academic findings and thus gaining insights on techniques that fit into TQM implementation. For academic professionals, several research avenues are pointed out.
2021
Autores
Almeida, F;
Publicação
Academia Letters
Abstract
2021
Autores
Macedo, PM; Fidalgo, JN; Saraiva, JT;
Publicação
2021 IEEE MADRID POWERTECH
Abstract
The financial planning of distribution systems usually includes the prediction of annual mandatory investments, concerning the resources that the DSO is compelled to allocate as a result of new network connections, required by new consumers or new energy producers. This paper presents a methodology to estimate the mandatory investments that the DSO should do in the distribution network. These estimations are based on historical data, load growth expectations and various socioeconomic indices. However, the available database contains very few annual investment examples (one aggregated value per year since 2002) compared to the large number of variables (potential inputs), which is a factor of regression overfitting. Thus, the applicable regression techniques are restrained to simple but efficient models. This paper describes a new methodology to identify the most suitable estimation models. The implemented application automatically builds, selects, and tests estimation models resulting from combinations of input variables. The final forecast is provided by a committee of models. Results obtained so far confirm the feasibility of the adopted methodology.
2021
Autores
Home-Ortiz, JM; Macedo, LH; Mantovani, JRS; Romero, R; Vargas, R; Catalao, JPS;
Publicação
2021 IEEE MADRID POWERTECH
Abstract
This paper presents a new stochastic mixed-integer second-order cone programming model to solve the problem of optimal operation of distribution systems considering network reconfiguration, voltage control devices, dispatchable and nondispatchable distributed generators (DGs), and the possibility of closed-loop topology operation. The decision variables are the active and reactive power generation of DGs, the tap position of substations' (SS) on-load tap changers and voltage regulators, the number of switchable capacitor banks in operation, and the operational statuses of sectionalizing and tie switches. The proposed formulation considers the minimization of (i) the cost of the energy purchased from the distribution SSs and dispatchable DGs, (ii) greenhouse gas emissions, (iii) technical energy losses, and (iv) the number of basic loops formed in the network. Tests are carried out using the 33-node system and the results demonstrate the effectiveness of the proposed formulation. The benefits provided by the presented approach include reduced operational costs and greenhouse gas emissions mitigation.
2021
Autores
Brandao, A; Resende, JS; Martins, R;
Publicação
COMPUTERS & SECURITY
Abstract
With the rising popularity of the cloud, companies lose control of both the hardware and the operating system responsible for hosting their software and data. This means that companies are at risk of losing confidential data when these are utilized in components controlled by a third-party cloud vendor. Secure enclaves can help solve this problem by creating a secure environment where code can be executed securely, guaranteeing that no unwanted parties read or modify the data inside this secure environment. While the use of secure enclaves has been focused on small footprints software, such as the implementation of trusted computing base for distributed protocols, we analyze the strengths and shortcoming of current tools in an effort to further expand the applicability of their use. Given the importance of web servers and their inherent greater exposure to attacks, we explore the hardening of Apache web server through the use of secure enclaves. This was accomplished by making the necessary modifications to further protect its private key from both the operating system and hypervisor. We also provide a performance assessment to quantify the overhead associated with the use of secure enclaves, namely, Intel SGX.
2021
Autores
Faria, N; Pereira, J; Alonso, AN; Vilaça, R;
Publicação
Heterogeneous Data Management, Polystores, and Analytics for Healthcare - VLDB Workshops, Poly 2021 and DMAH 2021, Virtual Event, August 20, 2021, Revised Selected Papers
Abstract
Transactional isolation is a challenge for polystores, as along with the limited capabilities of each datastore, we have to contend with their sheer diversity. However, transactional isolation is increasingly desirable as a variety of datastores are being sought after for roles that go beyond data lakes. Transactional guarantees are also relevant for reliability at scale. In this paper, we propose that transactional isolation in polystores can be achieved by leveraging the query engine, i.e., basing some of the responsibilities of a traditional transactional storage manager (TSM) on the query language itself. This has the key advantage of greatly simplifying design and implementation, as it doesn’t need to be re-invented for each datastore, and should increase performance, by taking advantage of dynamic query optimization where available. We demonstrate the feasibility of the proposal with a simple proof-of-concept and experiment. © 2021, Springer Nature Switzerland AG.
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