•A systematic mapping study on technical debt and its management.•Ninety-four papers are finally selected for data extraction and analysis.•Technical debt was classified into 10 types.•Eight ...activities of and 29 tools for technical debt management were identified.•Code-related technical debt has gained the most attention.
Technical debt (TD) is a metaphor reflecting technical compromises that can yield short-term benefit but may hurt the long-term health of a software system.
This work aims at collecting studies on TD and TD management (TDM), and making a classification and thematic analysis on these studies, to obtain a comprehensive understanding on the TD concept and an overview on the current state of research on TDM.
A systematic mapping study was performed to identify and analyze research on TD and its management, covering publications between 1992 and 2013.
Ninety-four studies were finally selected. TD was classified into 10 types, 8 TDM activities were identified, and 29 tools for TDM were collected.
The term “debt” has been used in different ways by different people, which leads to ambiguous interpretation of the term. Code-related TD and its management have gained the most attention. There is a need for more empirical studies with high-quality evidence on the whole TDM process and on the application of specific TDM approaches in industrial settings. Moreover, dedicated TDM tools are needed for managing various types of TD in the whole TDM process.
In this paper, a stable highly tunable and switchable multi-wavelength fiber laser is presented. It is based on the filtering characteristics of the Sagnac loop mirror and the polarization-dependent ...devices, the polarization hole burning effect is induced to generate multi-wavelength output with high optical signal-to-noise ratio and narrow 3 dB linewidth, optical signal-to-noise ratio is about 50 dB and linewidth is less than 0.02 nm. The tunable bandwidth is about 30 nm, which covers almost the entire C-band. By the adjusting polarization controller, the number and wavelength spacing of laser emissions can be controlled and switched. The single-wavelength exhibits good power and wavelength stability, the peak power fluctuation is less than 0.04 dB and the wavelength drift is less than 0.04 nm, and the wavelength spacing of the dual-wavelength can be tuned from 0.67 to 27.4 nm. In the proposed structure, multi-wavelength up to 6 laser emissions can be obtained span from 1528 to 1562 nm.
Public development projects (PDPs) and documented public development projects (DPDPs) are two types of projects that can provide valuable information on how developers and users participate in OSS ...projects. However, it is hard for researchers to effectively select PDPs and DPDPs due to the lack of specific project selection methods for these two types of projects. To address this problem, a standard dataset was labelled and the base line methods (i.e. selecting projects according to a single feature like star number) under 60 configurations and the machine learning methods under 18 configurations were tested to identify the best configurations in precision and F‐measure for selecting PDPs and DPDPs. The results show that (1) to select PDPs or DPDPs with a high precision, the base line method is the best with precision of 0.877 (PDPs) and 0.831 (DPDPs); (2) to select PDPs or DPDPs with a high F‐measure, the machine learning methods are the best, with F‐measure of 0.817 (PDPs) and 0.789 (DPDPs); (3) existing sample selection strategies can be combined with the machine learning methods, and the precision of selecting PDPs can be increased by 6.39%–41.33% and the precision of selecting DPDPs can be can be increased by 35.50%–269.02%.
A multi-wavelength Brillouin erbium-doped fiber laser sensor is proposed and investigated experimentally. It is a linear laser cavity multi-wavelength fiber laser, formed by fixing two ...high-reflectivity Sangac loop mirrors at both ends. We investigate the laser system output characteristics and test the sensor performance for different temperature. Temperature/humidity and reliable linear-cavity fiber laser sensing operation were successfully achieved. Experimental results show that the temperature sensitivity is
27.15
MHz/ °C and the measurement error caused by frequency drift is about
±
0.285
°C.
Glioblastoma stem cells (GSCs) reside in hypoxic periarteriolar niches of glioblastoma micro-environment, however, the crosstalk of GSCs with macrophages on regulating tumor angiogenesis and ...progression are not fully elucidated. GSCs-derived exosomes (GSCs-exos) are essential mediators during tumor immune-microenvironment remodeling initiated by GSCs, resulting in M2 polarization of tumor-associated macrophages (TAMs) as we reported previously. Our data disclosed aberrant upregulation of miR-374b-3p in both clinical glioblastoma specimens and human cell lines of GSCs. MiR-374b-3p level was high in GSCs-exos and can be internalized by macrophages. Mechanistically, GSCs exosomal miR-374b-3p induced M2 polarization of macrophages by downregulating phosphatase and tensin expression, thereby promoting migration and tube formation of vascular endothelial cells after coculture with M2 macrophages. Cumulatively, these data indicated that GSCs exosomal miR-374b-3p can enhance tumor angiogenesis by inducing M2 polarization of macrophages, as well as promote malignant progression of glioblastoma. Targeting exosomal miR-374b-3p may serve as a potential target against glioblastoma.
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•The miR-374b-3p was increased in clinical glioblastoma specimens, GSCs and GSCs-exos•GSCs-exos promoted glioblastoma angiogenesis through M2 polarization of macrophages•GSCs exosomal miR-374b-3p induced M2 polarization of macrophages by regulating PTEN
Cancer; Immunology; Molecular biology
Recent years have witnessed a rapid growth in using Web services for data publishing and sharing among organizations.To improve the efficiency of software development and economize on human and ...material resources,service reuse is viewed as a powerful means which will not only reuse atomic services,but also reuse arbitrary granularities of Service process fragments（SPFs）.However,effectively reusing arbitrary granularities of SPFs has not been solved yet,let alone taking diverse Qo S preferences of service providers and users into account.In this paper,we propose a novel method of SPF reuse,named SCKY,based on the Cocke-Kasami-Younger（CKY） algorithm.We first present an extended CKY to do SPF-query.Then we address how to do SPF-query by a probability CKY,i.e.,return a SPF with maximum emergence probability.Finally,we explore the SPF-query with a consensus of Qo S preferences between service providers and users.Through a set of experiments,the effectiveness and robustness of our approach are evaluated.
These days, the synchronization of multiplex networks is an emerging and important research topic. Grounded framework and theory about synchronization and control on multiplex networks are yet to ...come. This article studies the intralayer synchronization on a multiplex network (i.e., a set of networks connected through interlayer edges), via the pinning impulsive control method. The topologies of different layers are independent of each other, and the individual dynamics of nodes in different layers are different as well. Supra-Laplacian matrices are adopted to represent the topological structures of multiplex networks. Two cases are considered according to impulsive sequences of multiplex networks: 1) pinning controllers are applied to all the layers simultaneously at the instants of a common impulse sequence and 2) pinning controllers are applied to each layer at the instants of distinct impulse sequences. Using the Lyapunov stability theory and the impulsive control theory, several intralayer synchronization criteria for multiplex networks are obtained, in terms of the supra-Laplacian matrix of network topology, self-dynamics of nodes, impulsive intervals, and the pinning control effect. Furthermore, the algorithms for implementing pinning schemes at every impulsive instant are proposed to support the obtained criteria. Finally, numerical examples are presented to demonstrate the effectiveness and correctness of the proposed schemes.
Knowledge management technologies have been employed across software engineering activities for more than two decades. Knowledge-based approaches can be used to facilitate software architecting ...activities (e.g., architectural evaluation). However, there is no comprehensive understanding on how various knowledge-based approaches (e.g., knowledge reuse) are employed in software architecture.
This work aims to collect studies on the application of knowledge-based approaches in software architecture and make a classification and thematic analysis on these studies, in order to identify the gaps in the existing application of knowledge-based approaches to various architecting activities, and promising research directions.
A systematic mapping study is conducted for identifying and analyzing the application of knowledge-based approaches in software architecture, covering the papers from major databases, journals, conferences, and workshops, published between January 2000 and March 2011.
Fifty-five studies were selected and classified according to the architecting activities they contribute to and the knowledge-based approaches employed. Knowledge capture and representation (e.g., using an ontology to describe architectural elements and their relationships) is the most popular approach employed in architecting activities. Knowledge recovery (e.g., documenting past architectural design decisions) is an ignored approach that is seldom used in software architecture. Knowledge-based approaches are mostly used in architectural evaluation, while receive the least attention in architecture impact analysis and architectural implementation.
The study results show an increased interest in the application of knowledge-based approaches in software architecture in recent years. A number of knowledge-based approaches, including knowledge capture and representation, reuse, sharing, recovery, and reasoning, have been employed in a spectrum of architecting activities. Knowledge-based approaches have been applied to a wide range of application domains, among which “Embedded software” has received the most attention.
During the past decades, researchers have proposed numerous studies to predict bugs at different granularity levels, such as the file level, package level, module level, etc. However, the prediction ...models at the method level are rarely investigated.
In this paper, we investigate to predict bug-prone methods based on method-level code metrics or history measures, and analyze the prediction importance of each metric.
To proceed our study, we first propose a series of code metrics and history measures for conducting method-level bug predictions. Next, we compare the performance of different types of prediction models. Finally, we conduct analyses about the prediction power of each metric, based on which, we further analyze whether we can simplify the prediction models.
Through our evaluation on eighteen large-scale projects, we have presented: (1) conducting method-level bug prediction has potentials of saving a large portion of effort on code reviews and inspections; (2) models using the proposed code metrics or history measures could achieve a good prediction performance; (3) the prediction importance of each metric distributes differently; (4) a highly simplified prediction model could be derived by just using a few important metrics.
This study presents how to systematically build models for predicting bug-prone methods, and provides empirical evidence for developers to best select metrics to build method-level bug prediction models.
Memristor-based chaotic systems have been received great attention from researchers in the last decade. This brief investigates parameter identification of a memristor-based chaotic system (proposed ...by Muthuswamy in 2010). Uncertain parameter identification has not been studied yet for memristor-based chaotic systems. Using the Lyapunov stability theory and Barb ă lat lemma, two theorems are established to identify uncertain parameters of the system under the following two cases: i) the memductance is unknown; ii) capacitances and inductances are unknown. Finally, numerical simulations are carried out and the results show that the proposed parameter identification methods are effective.
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