Computing infrastructure issues in distributed communications systems : a survey of operating system transport system architectures

The performance of distributed applications (such as file transfer, remote login, tele-conferencing, full-motion video, and scientific visualization) is influenced by several factors that interact in complex ways. In particular, application performance is significantly affected both by communication infrastructure factors and computing infrastructure factors. Several communication infrastructure factors include channel speed, bit-error rate, and congestion at intermediate switching nodes. Computing infrastructure factors include (among other things) both protocol processing activities (such as connection management, flow control, error detection, and retransmission) and general operating system factors (such as memory latency, CPU speed, interrupt and context switching overhead, process architecture, and message buffering). Due to a several orders of magnitude increase in network channel speed and an increase in application diversity, performance bottlenecks are shifting from the network factors to the transport system factors.This paper defines an abstraction called an "Operating System Transport System Architecture" (OSTSA) that is used to classify the major components and services in the computing infrastructure. End-to-end network protocols such as TCP, TP4, VMTP, XTP, and Delta-t typically run on general-purpose computers, where they utilize various operating system resources such as processors, virtual memory, and network controllers. The OSTSA provides services that integrate these resources to support distributed applications running on local and wide area networks.A taxonomy is presented to evaluate OSTSAs in terms of their support for protocol processing activities. We use this taxonomy to compare and contrast five general-purpose commercial and experimental operating systems including System V UNIX, BSD UNIX, the x-kernel, Choices, and Xinu

Introductory programming: a systematic literature review

As computing becomes a mainstream discipline embedded in the school curriculum and acts as an enabler for an increasing range of academic disciplines in higher education, the literature on introductory programming is growing. Although there have been several reviews that focus on specific aspects of introductory programming, there has been no broad overview of the literature exploring recent trends across the breadth of introductory programming. This paper is the report of an ITiCSE working group that conducted a systematic review in order to gain an overview of the introductory programming literature. Partitioning the literature into papers addressing the student, teaching, the curriculum, and assessment, we explore trends, highlight advances in knowledge over the past 15 years, and indicate possible directions for future research

Automated analysis of feature models: Quo vadis?

Feature models have been used since the 90's to describe software product lines as a way of reusing common parts in a family of software systems. In 2010, a systematic literature review was published summarizing the advances and settling the basis of the area of Automated Analysis of Feature Models (AAFM). From then on, different studies have applied the AAFM in different domains. In this paper, we provide an overview of the evolution of this field since 2010 by performing a systematic mapping study considering 423 primary sources. We found six different variability facets where the AAFM is being applied that define the tendencies: product configuration and derivation; testing and evolution; reverse engineering; multi-model variability-analysis; variability modelling and variability-intensive systems. We also confirmed that there is a lack of industrial evidence in most of the cases. Finally, we present where and when the papers have been published and who are the authors and institutions that are contributing to the field. We observed that the maturity is proven by the increment in the number of journals published along the years as well as the diversity of conferences and workshops where papers are published. We also suggest some synergies with other areas such as cloud or mobile computing among others that can motivate further research in the future.Ministerio de Economía y Competitividad TIN2015-70560-RJunta de Andalucía TIC-186

Quantitative toxicity prediction using topology based multi-task deep neural networks

The understanding of toxicity is of paramount importance to human health and environmental protection. Quantitative toxicity analysis has become a new standard in the field. This work introduces element specific persistent homology (ESPH), an algebraic topology approach, for quantitative toxicity prediction. ESPH retains crucial chemical information during the topological abstraction of geometric complexity and provides a representation of small molecules that cannot be obtained by any other method. To investigate the representability and predictive power of ESPH for small molecules, ancillary descriptors have also been developed based on physical models. Topological and physical descriptors are paired with advanced machine learning algorithms, such as deep neural network (DNN), random forest (RF) and gradient boosting decision tree (GBDT), to facilitate their applications to quantitative toxicity predictions. A topology based multi-task strategy is proposed to take the advantage of the availability of large data sets while dealing with small data sets. Four benchmark toxicity data sets that involve quantitative measurements are used to validate the proposed approaches. Extensive numerical studies indicate that the proposed topological learning methods are able to outperform the state-of-the-art methods in the literature for quantitative toxicity analysis. Our online server for computing element-specific topological descriptors (ESTDs) is available at http://weilab.math.msu.edu/TopTox/Comment: arXiv admin note: substantial text overlap with arXiv:1703.1095

Taking advantage of the software product line paradigm to generate customized user interfaces for decision-making processes: a case study on university employability

[EN]University employment and, specifically, employability has gained relevance since research in these fields can lead to improvement in the quality of life of individual citizens. However, empirical research is still insufficient to make significant decisions, and relying on powerful tools to explore data and reach insights on these fields is paramount. Information dashboards play a key role in analyzing and visually exploring data about a specific topic or domain, but end users can present several necessities that differ from each other, regarding the displayed information itself, design features and even functionalities. By applying a domain engineering approach (within the software product line paradigm), it is possible to produce customized dashboards to fit into particular requirements, by the identification of commonalities and singularities of every product that could be part of the product line. Software product lines increase productivity, maintainability and traceability regarding the evolution of the requirements, among other benefits. To validate this approach, a case study of its application in the context of the Spanish Observatory for University Employability and Employment system has been developed, where users (Spanish universities and administrators) can control their own dashboards to reach insights about the employability of their graduates. These dashboards have been automatically generated through a domain specific language, which provides the syntax to specify the requirements of each user. The domain language fuels a template-based code generator, allowing the generation of the dashboards' source code. Applying domain engineering to the dashboards' domain improves the development and maintainability of these complex software products given the variety of requirements that users might have regarding their graphical interfaces

Combining Multiple Granularity Variability in a Software Product Line Approach for Web Engineering

[Abstract] Context: Web engineering involves managing a high diversity of artifacts implemented in different languages and with different levels of granularity. Technological companies usually implement variable artifacts of Software Product Lines (SPLs) using annotations, being reluctant to adopt hybrid, often complex, approaches combining composition and annotations despite their benefits. Objective: This paper proposes a combined approach to support fine and coarse-grained variability for web artifacts. The proposal allows web developers to continue using annotations to handle fine-grained variability for those artifacts whose variability is very difficult to implement with a composition-based approach, but obtaining the advantages of the composition-based approach for the coarse-grained variable artifacts. Methods: A combined approach based on feature modeling that integrates annotations into a generic composition-based approach. We propose the definition of compositional and annotative variation points with custom-defined semantics, which is resolved by a scaffolding-based derivation engine. The approach is evaluated on a real-world web-based SPL by applying a set of variability metrics, as well as discussing its quality criteria in comparison with annotations, compositional, and combined existing approaches. Results: Our approach effectively handles both fine and coarse-grained variability. The mapping between the feature model and the web artifacts promotes the traceability of the features and the uniformity of the variation points regardless of the granularity of the web artifacts. Conclusions: Using well-known techniques of SPLs from an architectural point of view, such as feature modeling, can improve the design and maintenance of variable web artifacts without the need of introducing complex approaches for implementing the underlying variability.The work of the authors from the Universidad de Málaga is supported by the projects Magic P12-TIC1814 (post-doctoral research grant), MEDEA RTI2018-099213-B-I00 (co-financed by FEDER funds), Rhea P18-FR-1081 (MCI/AEI/FEDER, UE), LEIA UMA18-FEDERIA-157, TASOVA MCIU-AEI TIN2017-90644-REDT and, European Union’s H2020 research and innovation program under grant agreement DAEMON 101017109. The work of the authors from the Universidade da Coruña has been funded by MCIN/AEI/10.13039/501100011033, NextGenerationEU/PRTR, FLATCITY-POC: PDC2021-121239-C31 ; MCIN/AEI/10.13039/501100011033 EXTRACompact: PID2020-114635RB-I00 ; GAIN/Xunta de Galicia/ERDF CEDCOVID: COV20/00604 ; Xunta de Galicia/FEDER-UE GRC: ED431C 2021/53 ; MICIU/FEDER-UE BIZDEVOPSGLOBAL: RTI-2018-098309-B-C32 ; MCIN/AEI/10.13039/501100011033 MAGIST: PID2019-105221RB-C41Junta de Andalucía; P12-TIC-1814Universidad de Málaga; UMA18-FEDERIA-157Xunta de Galicia; COV20/00604Xunta de Galicia; ED431C 2021/53Junta de Andalucía; P18-FR-108

A Model-Driven Approach for the Design, Implementation, and Execution of Software Development Methods

[EN] Software development projects are diverse in nature. For this reason, software companies are often forced to define their methods in-house. In order to define methods efficiently and effectively, software companies require systematic solutions that are built upon sound methodical foundations. Providing these solutions is the main goal of the Method Engineering discipline. Method Engineering is the discipline to design, construct, and adapt methods, techniques, and tools for the development of information systems. Over the last two decades, a lot of research work has been performed in this area. However, despite its potential benefits, Method Engineering is not widely used in industrial settings. Some of the causes of this reality are the high theoretical complexity of Method Engineering and the lack of adequate software support. In this thesis, we aim to mitigate some of the problems that affect Method Engineering by providing a novel methodological approach that is built upon Model-Driven Engineering (MDE) foundations. The use of MDE enables a rise in abstraction, automation, and reuse that allows us to alleviate the complexity of our Method Engineering approach. Furthermore, by leveraging MDE techniques (such as metamodeling, model transformations, and models at runtime), our approach supports three phases of the Method Engineering lifecycle: design, implementation, and execution. This is unlike traditional Method Engineering approaches, which, in general, only support one of these phases. In order to provide software support for our proposal, we developed a Computer-Aided Method Engineering (CAME) environment that is called MOSKitt4ME. To ensure that MOSKitt4ME offered the necessary functionality, we identified a set of functional requirements prior to developing the tool. Then, after these requirements were identified, we defined the architecture of our CAME environment, and, finally, we implemented the architecture in the context of Eclipse. The thesis work was evaluated by means of a study that involved the participation of end users. In this study, MOSKitt4ME was assessed by means of the Technology Acceptance Model (TAM) and the Think Aloud method. While the TAM allowed us to measure usefulness and ease of use in a subjective manner, the Think Aloud method allowed us to analyze these measures objectively. Overall, the results were favorable. MOSKitt4ME was highly rated in perceived usefulness and ease of use; we also obtained positive results with respect to the users' actual performance and the difficulty experienced.[ES] Los proyectos de desarrollo de software son diversos por naturaleza. Por este motivo, las compañías de software se ven forzadas frecuentemente a definir sus métodos de manera interna. Para poder definir métodos de forma efectiva y eficiente, las compañías necesitan soluciones sistemáticas que estén definidas sobre unos fundamentos metodológicos sólidos. Proporcionar estas soluciones es el principal objetivo de la Ingeniería de Métodos. La Ingeniería de Métodos es la disciplina que aborda el diseño, la construcción y la adaptación de métodos, técnicas y herramientas para el desarrollo de sistemas de información. Durante las dos últimas décadas, se ha llevado a cabo mucho trabajo de investigación en esta área. Sin embargo, pese a sus potenciales beneficios, la Ingeniería de Métodos no se aplica ampliamente en contextos industriales. Algunas de las principales causas de esta situación son la alta complejidad teórica de la Ingeniería de Métodos y la falta de un apropiado soporte software. En esta tesis, pretendemos mitigar algunos de los problemas que afectan a la Ingeniería de Métodos proporcionando una propuesta metodológica innovadora que está basada en la Ingeniería Dirigida por Modelos (MDE). El uso de MDE permite elevar el nivel de abstracción, automatización y reuso, lo que posibilita una reducción de la complejidad de nuestra propuesta. Además, aprovechando técnicas de MDE (como por ejemplo el metamodelado, las transformaciones de modelos y los modelos en tiempo de ejecución), nuestra aproximación da soporte a tres fases del ciclo de vida de la Ingeniería de Métodos: diseño, implementación y ejecución. Esto es a diferencia de las propuestas existentes, las cuales, por lo general, sólo dan soporte a una de estas fases. Con el objetivo de proporcionar soporte software para nuestra propuesta, implementamos una herramienta CAME (Computer-Aided Method Engineering) llamada MOSKitt4ME. Para garantizar que MOSKitt4ME proporcionaba la funcionalidad necesaria, definimos un conjunto de requisitos funcionales como paso previo al desarrollo de la herramienta. Tras la definción de estos requisitos, definimos la arquitectura de la herramienta CAME y, finalmente, implementamos la arquitectura en el contexto de Eclipse. El trabajo desarrollado en esta tesis se evaluó por medio de un estudio donde participaron usuarios finales. En este estudio, MOSKitt4ME se evaluó por medio del Technology Acceptance Model (TAM) y del método Think Aloud. Mientras que el TAM permitió medir utilidad y facilidad de uso de forma subjetiva, el método Think Aloud permitió analizar estas medidas objetivamente. En general, los resultados obtenidos fueron favorables. MOSKitt4ME fue valorado de forma positiva en cuanto a utilidad y facilidad de uso percibida; además, obtuvimos resultados positivos en cuanto al rendimiento objetivo de los usuarios y la dificultad experimentada.[CA] Els projectes de desenvolupament de programari són diversos per naturalesa. Per aquest motiu, les companyies es veuen forçades freqüenment a definir els seus mètodes de manera interna. Per poder definir mètodes de forma efectiva i eficient, les companyies necessiten solucions sistemàtiques que estiguin definides sobre uns fundaments metodològics sòlids. Proporcionar aquestes solucions és el principal objectiu de l'Enginyeria de Mètodes. L'Enginyeria de Mètodes és la disciplina que aborda el diseny, la construcció i l'adaptació de mètodes, tècniques i eines per al desenvolupament de sistemes d'informació. Durant les dues últimes dècades, s'ha dut a terme molt de treball de recerca en aquesta àrea. No obstant, malgrat els seus potencials beneficis, l'Enginyeria de Mètodes no s'aplica àmpliament en contextes industrials. Algunes de les principals causes d'aquesta situació són l'alta complexitat teòrica de l'Enginyeria de Mètodes i la falta d'un apropiat suport de programari. En aquesta tesi, pretenem mitigar alguns dels problemes que afecten a l'Enginyeria de Mètodes proporcionant una proposta metodològica innovadora que està basada en l'Enginyeria Dirigida per Models (MDE). L'ús de MDE ens permet elevar el nivell d'abstracció, automatització i reutilització, possibilitant una reducció de la complexitat de la nostra proposta. A més a més, aprofitant tècniques de MDE (com per exemple el metamodelat, les transformacions de models i els models en temps d'execució), la nostra aproximació suporta tres fases del cicle de vida de l'Enginyeria de Mètodes: diseny, implementació i execució. Açò és a diferència de les propostes existents, les quals, en general, només suporten una d'aquestes fases. Amb l'objectiu de proporcionar suport de programari per a la nostra proposta, implementàrem una eina CAME (Computer-Aided Method Engineering) anomenada MOSKitt4ME. Per garantir que MOSKitt4ME oferia la funcionalitat necessària, definírem un conjunt de requisits funcionals com a pas previ al desenvolupament de l'eina. Després de la definició d'aquests requisits, definírem la arquitectura de l'eina CAME i, finalment, implementàrem l'arquitectura en el contexte d'Eclipse. El treball desenvolupat en aquesta tesi es va avaluar per mitjà d'un estudi on van participar usuaris finals. En aquest estudi, MOSKitt4ME es va avaluar per mitjà del Technology Acceptance Model (TAM) i el mètode Think Aloud. Mentre que el TAM va permetre mesurar utilitat i facilitat d'ús de manera subjectiva, el mètode Think Aloud va permetre analitzar aquestes mesures objectivament. En general, els resultats obtinguts van ser favorables. MOSKitt4ME va ser valorat de forma positiva pel que fa a utilitat i facilitat d'ús percebuda; a més a més, vam obtenir resultats positius pel que fa al rendiment objectiu dels usuaris i a la dificultat experimentada.Cervera Úbeda, M. (2015). A Model-Driven Approach for the Design, Implementation, and Execution of Software Development Methods [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/53931TESI

Design Models for Service-based Software Application

Context: The use of a Service Oriented Architecture (SOA) offers a new and distinct approach to creating software based applications (SBAs) around the idea of integrating distributed autonomous computing resources. A widely available realisation of an SOA exists in the form of web services. However, to date no standard techniques have emerged for developing SBAs. There is also a lack of consistency in describing the concept itself, and the published literature offers little evidence derived from the experience of developing `real world examples. Aims: The objective of the work described in this thesis was to conduct a series of studies to explore systematically the concept of what constitutes an SOA by using the published literature, to employ this to construct a proof of concept SOA design model based on a real world problem, and in doing so, to investigate how well existing design notations are able to support this architectural style. Method: The research described in this thesis has been conducted in an evolutionary manner by employing a range of empirical methods. A mapping study was performed to investigate how the concept of SOA is interpreted by the research community. Based upon this model of SOA, a participant-observer case study was employed to construct an SOA design model and a use case model for an energy engineering application to demonstrate use for a real world problem. Finally, expert knowledge was employed for evaluation of the case study through the use of walkthroughs. Results: From the mapping study we created an integrated model of what constitutes an SOA for the use with the case study. The case study outcomes include a design for a renewable energy control system together with codified experience of constructing and recording the SOA design model. The experience of employing the walkthrough method for evaluation, and the outcomes of the evaluation are also discussed. Conclusion: From this research we conclude that the SOA research community needs to develop a clearer shared understanding and agreement on the model of what constitutes an SOA and the vocabulary used to describe the SOA concept. This will aid designers to communicate their mental models more effectively and will provide the semantics needed for devising the new notations that this study implies are needed for SBA design. Further, some lessons about SBA design have been derived from the case study experiences