Source code metrics: A systematic mapping study Nuñez-Varela, Alberto S.; Pérez-Gonzalez, Héctor G.; Martínez-Perez, Francisco E. ...
The Journal of systems and software,
June 2017, 2017-06-00, Letnik:
128
Journal Article
Recenzirano
•Three major programming paradigms measured by source code metrics were identified.•The CK metrics and the object oriented paradigm are the most studied subjects.•Java benchmark systems are the most ...commonly measured systems in research.•Technology on metrics extraction mechanisms are not up to research advances.•Empirical studies have a major impact on the code metrics community.
Source code metrics are essential components in the software measurement process. They are extracted from the source code of the software, and their values allow us to reach conclusions about the quality attributes measured by the metrics.
This paper aims to collect source code metrics related studies, review them, and perform an analysis, while providing an overview on the current state of source code metrics and their current trends.
A systematic mapping study was conducted. A total of 226 studies, published between the years 2010 and 2015, were selected and analyzed.
Almost 300 source code metrics were found. Object oriented programming is the most commonly studied paradigm with the Chidamber and Kemerer metrics, lines of code, McCabe's cyclomatic complexity, and number of methods and attributes being the most used metrics. Research on aspect and feature oriented programming is growing, especially for the current interest in programming concerns and software product lines.
Object oriented metrics have gained much attention, but there is a current need for more studies on aspect and feature oriented metrics. Software fault prediction, complexity and quality assessment are recurrent topics, while concerns, big scale software and software product lines represent current trends.
Symmetric Positive Definite (SPD) matrices are ubiquitous in data analysis under the form of covariance matrices or correlation matrices. Several O(n)-invariant Riemannian metrics were defined on the ...SPD cone, in particular the kernel metrics introduced by Hiai and Petz. The class of kernel metrics interpolates between many classical O(n)-invariant metrics and it satisfies key results of stability and completeness. However, it does not contain all the classical O(n)-invariant metrics. Therefore in this work, we investigate super-classes of kernel metrics and we study which key results remain true. We also introduce an additional key result called cometric-stability, a crucial property to implement geodesics with a Hamiltonian formulation. Our method to build intermediate embedded classes between O(n)-invariant metrics and kernel metrics is to give a characterization of the whole class of O(n)-invariant metrics on SPD matrices and to specify requirements on metrics one by one until we reach kernel metrics. As a secondary contribution, we synthesize the literature on the main O(n)-invariant metrics, we provide the complete formula of the sectional curvature of the affine-invariant metric and the formula of the geodesic parallel transport between commuting matrices for the Bures-Wasserstein metric.
In contrast to SPD matrices, few tools exist to perform Riemannian statistics on the open elliptope of full-rank correlation matrices. The quotient-affine metric was recently built as the quotient of ...the affine-invariant metric by the congruence action of positive diagonal matrices. The space of SPD matrices had always been thought of as a Riemannian homogeneous space. In contrast, we view in this work SPD matrices as a Lie group and the affine-invariant metric as a left-invariant metric. This unexpected new viewpoint allows us to generalize the construction of the quotient-affine metric and to show that the main Riemannian operations can be computed numerically. However, the uniqueness of the Riemannian logarithm or the Fréchet mean are not ensured, which is bad for computing on the elliptope. Hence, we define three new families of Riemannian metrics on full-rank correlation matrices which provide Hadamard structures, including two flat. Thus the Riemannian logarithm and the Fréchet mean are unique. We also define a nilpotent group structure for which the affine logarithm and the group mean are unique. We provide the main Riemannian/group operations of these four structures in closed form.
Traditionally, the success of a researcher is assessed by the number of publications he or she publishes in peer-reviewed, indexed, high impact journals. This essential yardstick, often referred to ...as the impact of a specific researcher, is assessed through the use of various metrics. While researchers may be acquainted with such matrices, many do not know how to use them to enhance their careers. In addition to these metrics, a number of other factors should be taken into consideration to objectively evaluate a scientist's profile as a researcher and academician. Moreover, each metric has its own limitations that need to be considered when selecting an appropriate metric for evaluation. This paper provides a broad overview of the wide array of metrics currently in use in academia and research. Popular metrics are discussed and defined, including traditional metrics and article-level metrics, some of which are applied to researchers for a greater understanding of a particular concept, including varicocele that is the thematic area of this Special Issue of Asian Journal of Andrology. We recommend the combined use of quantitative and qualitative evaluation using judiciously selected metrics for a more objective assessment of scholarly output and research impact.
Universities and funders need robust metrics to help them develop and monitor evidence-based strategies. Metrics are a part, albeit an important part, of the evaluation landscape, and no single ...metric can paint a holistic picture or inform strategy. A “basket of metrics” alongside other evaluation methods such as peer review are needed. Snowball Metrics offer a robust framework for measuring research performance and related data exchange and analysis, providing a consistent approach to information and measurement between institutions, funders and government bodies. The output of Snowball Metrics is a set of mutually agreed and tested methodologies: “recipes”. These recipes are available free-of-charge and can be used by anyone for their own purposes. A freely available API: the Snowball Metrics Exchange service (SMX), acts as a free “broker service” for the exchange of Snowball Metrics between peer institutions who agree that they would like to share information with each other and any institution can become a member of the SMX. In this paper, we present a use case where the University of St Andrews reviewed its institutional level KPIs referring to the Snowball Metrics recipes. In conclusion, quantitative data inform, but do not and should not ever replace, peer review judgments of research quality – whether in a national assessment exercise, or for any other purpose. Metrics can support human judgment and direct further investigation to pertinent areas, thus contributing to a fully rounded view on the research question being asked. We suggest using a “basket of metrics” approach measuring multiple qualities and applied to multiple entities.
Network defenses based on traditional tools, techniques, and procedures (TTP) fail to account for the attacker's inherent advantage present due to the static nature of network services and ...configurations. To take away this asymmetric advantage, Moving Target Defense (MTD) continuously shifts the configuration of the underlying system, in turn reducing the success rate of cyberattacks. In this survey, we analyze the recent advancements made in the development of MTDs and highlight (1) how these defenses can be defined using common terminology, (2) can be made more effective with the use of artificial intelligence techniques for decision making, (3) be implemented in practice and (4) evaluated. We first define an MTD using a simple and yet general notation that captures the key aspects of such defenses. We then categorize these defenses into different sub-classes depending on what they move, when they move and how they move. In trying to answer the latter question, we showcase the use of domain knowledge and game-theoretic modeling can help the defender come up with effective and efficient movement strategies. Second, to understand the practicality of these defense methods, we discuss how various MTDs have been implemented and find that networking technologies such as Software Defined Networking and Network Function Virtualization act as key enablers for implementing these dynamic defenses. We then briefly highlight MTD test-beds and case-studies to aid readers who want to examine or deploy existing MTD techniques. Third, our survey categorizes proposed MTDs based on the qualitative and quantitative metrics they utilize to evaluate their effectiveness in terms of security and performance. We use well-defined metrics such as risk analysis and performance costs for qualitative evaluation and metrics based on Confidentiality, Integrity, Availability (CIA), attack representation, QoS impact, and targeted threat models for quantitative evaluation. Finally, we show that our categorization of MTDs is effective in identifying novel research areas and highlight directions for future research.
In this paper, we prove that a spherically symmetric Finsler metric is a stretch metric if and only if it is R-quadratic. This yields an extension of Sadeghzadeh’s result that characterized the ...R-quadratic spherically symmetric Finsler metric. Then we find the necessary and sufficient condition under which a spherically symmetric Finsler metric is a weakly stretch metric. Finally, we study one of the important open problems in Finsler geometry presented by Matsumoto–Shimada about the existence of a L-reducible Finsler metric which is not C-reducible.
A PEC do Orçamento Impositivo trouxe mudanças na forma como o Legislativo interage com o Executivo no planejamento orçamentário. A imposição orçamentária traz alguns debates como a comparação com o ...modelo autorizativo, o mais adotado no Brasil, qual a relação político-partidária estabelecida entre os poderes e se essas mudanças podem ser benéficas para o serviço público. De modo igual, o encaminhamento de recursos orçamentários às instituições traz a atenção em avaliar os seus respectivos desempenhos. No caso das universidades federais, os indicadores de desempenho definidos pelo Tribunal de Contas da União (TCU) constituem um dos instrumentos de avaliação de desempenho. O objetivo do presente estudo foi analisar a relação das emendas parlamentares destinadas às Universidades Federais com os indicadores de desempenho do TCU. Foram analisadas as universidades federais brasileiras por meio da análise de correlação não-paramétrica de Spearman e a utilização de uma variável chamada Índice de Empenho Orçamentário por Emendas (ILORE), para verificar possíveis efeitos do empenho orçamentário de emendas parlamentares em contraste com os indicadores de desempenho do TCU. Os resultados indicaram que o ILORE se relacionou de maneira inversa e fraca em 6 dos 10 indicadores, o total de despesas empenhadas se relacionou de maneira positiva em 9 dos 10 indicadores, e que o total de despesas empenhadas oriundas de emendas se relacionou de maneira positiva em 4 dos 10 indicadores.
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