| 1. |
- Ranjan, Rajiv, et al.
(författare)
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MediaWise Cloud Content Orchestrator
- 2013
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Ingår i: Journal of Internet Services and Applications. - : Sociedade Brasileira de Computacao - SB. - 1867-4828 .- 1869-0238. ; 4:2
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Tidskriftsartikel (refereegranskat)abstract
- The growing ubiquity of Internet and cloud computing is having significant impact on media-related industries. These industries are using the Internet and cloud as a medium to enable creation, search, management and consumption of their content. Primarily, Content Delivery Networks (CDNs) are deployed for distributing multimedia content to the end-users. However, existing approaches to architecting CDNs have several limitations. Firstly, they do not harness multiple public cloud services for optimizing cost to performance ratio. Secondly, they lack support for dynamic and personalized content creation and distribution. Finally, they do not support end-to-end content lifecycle operations (production, deployment, consumption, personalization, and distribution).To overcome these limitations, in this paper, we propose, develop and validate a novel system called MediaWise Cloud Content Orchestrator (MCCO). MCCO expands the scope of existing CDNs with novel multi-cloud deployment. It enables content personalization and collaboration capabilities. Further, it facilitates do-it-yourself creation, search, management, and consumption of multimedia content. It inherits the pay-as-you-go models and elasticity that are offered by commercially available cloud services.In this paper, we discuss our vision, the challenges and the research objectives pertaining to MCCO for supporting next generation streamed, interactive, and collaborative high resolution multimedia content. We validated our system thorugh MCCO prototype implementation. Further, we conducted a set of experiments to demonstrate the functionality of MCCO. Finally, we compare the content orchestration features supported by MCCO to existing CDNs against the envisioned objectives of MCCO.
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| 2. |
- Abbaspour Asadollah, Sara, et al.
(författare)
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Concurrency bugs in open source software : a case study
- 2017
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Ingår i: Journal of Internet Services and Applications. - : Springer London. - 1867-4828 .- 1869-0238. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Concurrent programming puts demands on software debugging and testing, as concurrent software may exhibit problems not present in sequential software, e.g., deadlocks and race conditions. In aiming to increase efficiency and effectiveness of debugging and bug-fixing for concurrent software, a deep understanding of concurrency bugs, their frequency and fixing-times would be helpful. Similarly, to design effective tools and techniques for testing and debugging concurrent software, understanding the differences between non-concurrency and concurrency bugs in real-word software would be useful. This paper presents an empirical study focusing on understanding the differences and similarities between concurrency bugs and other bugs, as well as the differences among various concurrency bug types in terms of their severity and their fixing time, and reproducibility. Our basis is a comprehensive analysis of bug reports covering several generations of five open source software projects. The analysis involves a total of 11860 bug reports from the last decade, including 351 reports related to concurrency bugs. We found that concurrency bugs are different from other bugs in terms of their fixing time and severity while they are similar in terms of reproducibility. Our findings shed light on concurrency bugs and could thereby influence future design and development of concurrent software, their debugging and testing, as well as related tools.
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| 3. |
- Gamalielsson, Jonas, et al.
(författare)
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On organisational involvement and collaboration in W3C standards through editorship
- 2017
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Ingår i: Journal of Internet Services and Applications. - : Hindawi Publishing Corporation. - 1867-4828 .- 1869-0238. ; 8:1, s. 5:1-5:26
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Tidskriftsartikel (refereegranskat)abstract
- Over time, a number of open standards have been developed and implemented in software for addressing a number of challenges, such as lock-in, interoperability and longevity of software systems and associated digital artefacts. An understanding of organisational involvement and collaboration in standardisation is important for informing any future policy and organisational decisions concerning involvement in standardisation. The overarching goal of the study is toestablish how organisations contribute to open standards development through editorship. Specifically, the focus is on open standards development in the World Wide Web Consortium (W3C). Through an analysis of editorship for all W3C recommendations we contribute novel findings concerning organisational involvement and collaboration, and highlight contributions from different types of organisations and countries. We make five principal contributions. First, we establish an overall characterisation of organisational involvement in W3C standardisation. Second, we report on organisational involvement in W3C standardisation over time. Third, we establish how different organisations, organisation types, and countries are involved in W3C technologies. Fourth, we report on organisational involvement in relation to standard development time. Fifth, we establish how organisations collaborate in W3C standardisation through social network analysis.
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| 4. |
- Lindman, Juho, 1979, et al.
(författare)
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Support mechanisms provided by FLOSS foundations and other entities
- 2018
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Ingår i: Journal of Internet Services and Applications. - : Sociedade Brasileira de Computacao - SB. - 1867-4828 .- 1869-0238. ; 9:8
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Tidskriftsartikel (refereegranskat)abstract
- Foundations function as a vital institutional support infrastructure for many of the most successful open-source projects, but the different roles played by these support entities are understudied in Free/Libre and Open Source Software (FLOSS) research. Drawing on Open Hub (formerly known as Ohloh) data, this paper empirically investigates how these entities support projects and interact with other projects. This study was conducted using the Theoretical Saturation Grounded Theory approach given the large volume of data on hand. The findings are synthesized as a taxonomy of support entities, a categorization of support mechanisms and a set of dynamics of the interactions between different FLOSS support entities.
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| 5. |
- Poo-Caamaño, Germán, et al.
(författare)
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Herding cats in a FOSS ecosystem: a tale of communication and coordination for release management
- 2017
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Ingår i: Journal of Internet Services and Applications. - : Sociedade Brasileira de Computacao - SB. - 1867-4828 .- 1869-0238. ; 8:1, s. Article number 12-
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Tidskriftsartikel (refereegranskat)abstract
- Release management in large-scale software development projects requires significant communication and coordination. It is particularly challenging in Free and Open Source Software (FOSS) ecosystems, in which hundreds of loosely connected developers and their projects are coordinated to release software to a schedule. To better understand this process and its challenges, we analyzed over two and half years of communication in the GNOME ecosystem and studied developers’ interactions. Through a case study, we cataloged communication channels, determined the main channel from which we categorized high level communication and coordination activities spanning five releases, and triangulated our results by interviewing ten key developers. We found that a release schedule, influence (instead of direct control), and diversity are the main factors that positively impact the release process in the GNOME ecosystem. We report a set of lessons learned that encapsulates our understanding of how the Release Management process function in a FOSS ecosystem, we learned that: (1) ensure that the release team follows the main communication channels used by developers, (2) provide a common place for coordination for an ecosystem, (3) consider including both good technical and social skills in a release team, (4) aim for a diverse release team, (5) based on lack of power, lobbying and consensus based management must be followed, (6) help the release team in the coordination process with a well defined schedule, and (7) release team work is different from regular software work. Our results can help organizations build better large-scale teams and show that research focused on individual projects might miss important parts of the picture. © 2017, The Author(s).
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| 6. |
- Sirjani, Marjan, et al.
(författare)
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Towards a Verification-Driven Iterative Development of Software for Safety-Critical Cyber-Physical Systems
- 2021
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Ingår i: Journal of Internet Services and Applications. - : Springer Science and Business Media Deutschland GmbH. - 1867-4828 .- 1869-0238. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Software systems are complicated, and the scientific and engineering methodologies for software development are relatively young. Cyber-physical systems are now in every corner of our lives, and we need robust methods for handling the ever-increasing complexity of their software systems. Model-Driven Development is a promising approach to tackle the complexity of systems through the concept of abstraction, enabling analysis at earlier phases of development. In this paper, we propose a model-driven approach with a focus on guaranteeing safety using formal verification. Cyber-physical systems are distributed, concurrent, asynchronous and event-based reactive systems with timing constraints. The actor-based textual modeling language, Rebeca, with model checking support is used for formal verification. Starting from structured requirements and system architecture design the behavioral models, including Rebeca models, are built. Properties of interest are also derived from the structured requirements, and then model checking is used to formally verify the properties. This process can be performed in iterations until satisfaction of desired properties are ensured, and possible ambiguities and inconsistencies in requirements are resolved. The formally verified models can then be used to develop the executable code. The Rebeca models include the details of the signals and messages that are passed at the network level including the timing, and this facilitates the generation of executable code. The natural mappings among the models for requirements, the formal models, and the executable code improve the effectiveness and efficiency of the approach. © 2021, The Author(s).
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| 7. |
- Gharehbaghi, Arash, et al.
(författare)
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A Novel Method for Screening Children with Isolated Bicuspid Aortic Valve
- 2015
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Ingår i: Cardiovascular Engineering and Technology. - : Springer Science and Business Media LLC. - 1869-408X .- 1869-4098. ; 6:4, s. 546-556
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a novel processing method for heart sound signal: the statistical time growing neural network (STGNN). The STGNN performs a robust classification by merging supervised and unsupervised statistical methods to overcome non-stationary behavior of the signal. By combining available preprocessing and segmentation techniques and the STGNN classifier, we build an automatic tool for screening children with isolated BAV, the congenital heart malformation which can lead to serious cardiovascular lesions. Children with BAV (22 individuals) and healthy condition (28 individuals) are subjected to the study. The performance of the STGNN is compared to that of a time growing neural network (CTGNN) and a conventional support vector (CSVM) machine, using balanced repeated random sub sampling. The average of the accuracy/sensitivity is estimated to be 87.4/86.5 for the STGNN, 81.8/83.4 for the CTGNN, and 72.9/66.8 for the CSVM. Results show that the STGNN offers better performance and provides more immunity to the background noise as compared to the CTGNN and CSVM. The method is implementable in a computer system to be employed in primary healthcare centers to improve the screening accuracy.
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| 8. |
- Forkman, Peter, 1959, et al.
(författare)
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Six years of mesospheric CO estimated from ground-based frequency-switched microwave radiometry at 57° N compared with satellite instruments
- 2012
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 5:5, s. 2827-2841
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of mesospheric carbon monoxide, CO, provide important information about the dynamics in the mesosphere region since CO has a long lifetime at these altitudes. Ground-based measurements of mesospheric CO made at the Onsala Space Observatory, OSO, (57 °N, 12° E) are presented. The dataset covers the period 2002-2008 and is hence uniquely long for ground-based observations. The simple and stable 115 GHz frequency-switched radiometer, calibration method, retrieval procedure and error characterization are described. A comparison between our measurements and co-located CO measurements from the satellite sensors ACE-FTS on Scisat (v2.2), MLS on Aura (v3-3), MIPAS on Envisat (V3O-CO-12 + 13 and V4O-CO-200) and SMR on Odin (v225 and v021) is carried out. Our instrument, OSO, and the four satellite instruments show the same general variation of the vertical distribution of mesospheric CO in both the annual cycle and in shorter time period events, with high CO mixing ratios during winter and very low amounts during summer in the observed 55-100 km altitude range. During 2004-2008 the agreement of the OSO instrument and the satellite sensors ACE-FTS, MLS and MIPAS (200) is good in the altitude range 55-70 km. Above 70 km, OSO shows up to 25% higher CO column values compared to both ACE and MLS. For the time period 2002-2004, CO from MIPAS (12 + 13) is up to 50% lower than OSO between 55 and 70 km. Mesospheric CO from the two versions of SMR deviates up to ±65% when compared to OSO, but the analysis is based on only a few co-locations. © 2012 Author(s).
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