1,246 research outputs found
Spotify tailoring for promoting effectiveness in cross-functional autonomous squads
Organisations tend to tailor agile methods to scale employed practices to have cross-functional autonomous teams while promoting sustainable creative and productive development at a constant pace. Thus, it is important to investigate how organisations tailor agile practices to get the balance right between teams' autonomy and alignment. Spotify model is originally introduced to facilitate the development of music streaming services in a very large-scale project with a Business-to-Consumer (B2C) model. However, developing a large-scale mission-critical project with a Business-to-Business (B2B) model is not essentially supported by the Spotify model. Thus, embracing Spotify model for such projects should be concerned about the question of how Spotify practices are adjusted to promote the effectiveness of cross-functional autonomous squads in a mission-critical project with B2B model?
In this paper, we conduct a longitudinal embedded case study, which lasted 21 months during which 14 semi-structured interviews were conducted. The Grounded Theory (GT) is adopted to analyse the collected data. As a result, we identify practices and processes that promote effectiveness in cross-functional autonomous squads, which have never been discussed in terms of Spotify model before. We also present Spotify Tailoring by highlighting modified and newly introduced practices by the organisation in which the case study was conducted
A safety-centric change management framework by tailoring agile and V-Model processes
Safety critical systems are evolutionary and subject to preventive, perfective, corrective or adaptive changes during their lifecycle. Changes to any part of those systems can undermine the confidence in safety since changes can refute articulated claims about safety or challenge the supporting evidence on which this confidence relies. Changes to the software components are no exception. In order to maintain the confidence in the safety performance, developers must update their system and its safety case. Agile methodologies are known to embrace changes to software where agilists strive to manage changes, not to prevent them. In this paper, we introduce a novel framework in which we tailor a hybrid process of agile software development and the traditional V-model. The tailored process aims to facilitate the accommodation of non-structural changes to the software parts of safety critical systems. We illustrate our framework in the context of ISO 26262 safety standard
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Modeling of wind energy conversion system using PSCAD/EMTDC
This paper aims to model a complete wind energy conversion system (WECS) connected to a grid. The motivation comes from the Distributed Generation System (DGS) installed at the Renewable Energy Lab at UMass Lowell. The objective of this work is to develop universal and standardized manufacturer independent textbook models. Manufacturer specific models are more accurate and detailed, but proprietary and non-disclosure agreements become an issue for research purposes. Since the wind turbines installed in the lab are VSWT (Variable Speed Wind Turbine) with Permanent Magnet Synchronous Generators (PMSG), so such a turbine system is modeled to represent them in general. PMSG requires very less maintenance and has high efficiency since it doesn't have rotor current and is used without a gearbox. Further, there are two more advantages: first, it has the capability of variable speed control due to the fact that its rotor speed can change in a large range; second, it's excitation system is independent of the grid and require any other excitation source. In addition to the turbine generator, other main components of WECS are also modeled namely: wind source model, wind turbine, permanent magnet synchronous generator and AC/DC/AC control. The equations governing these models are also discussed. The entire generation system is implemented on PSCAD/EMTDC and integrated to a grid and a basic fault analysis is done under different conditions. The proposed model can be used for research purposes on distributed generation issues. This model provides a good software simulation test bed for further research
Évolution de la température de l’air et des précipitations dans la région côtière syrienne (gouvernorat de Lattaquié) de 1970 à 2016
This study aims to analyze the changes in the annual and seasonal averages of air temperature and precipitation over Lattakia Governorate during the period 1970-2016. Annual and seasonal trends for temperature and precipitation were calculated by using the non-parametric Mann-Kendall test. The mean differences between the two periods 1970-2000 and 2001-2016, were assessed at the annual and seasonal scales by using the non-parametric Mann-Whitney U test. Furthermore, the occurrence of extreme high/low values were analyzed at the annual scale by using the normal distribution curve. The study found that the annual temperature averages significantly (p<0.05) increased by 0.22 ËšC/decade and 0.17 ËšC/decade, respectively at Lattakia and Hiffeh stations during the period 1970-2016. Summer exhibited strong and significant (at level 0.01) increasing trends by 0.39 ËšC/decade at Lattakia, and by 0.34 ËšC/decade at Hiffeh. Total spring precipitation significantly decreased by -6.5 mm/decade at Lattakia and by -12.1 mm/decade at Hiffeh. Probability of the occurrence of the value 20.2 ËšC or more as an extreme value increased by 40.8% at Lattakia station during the period 2001-2016. Este estudio tiene como objetivo analizar los cambios en los promedios anuales y estacionales de la temperatura del aire y las precipitaciones en la gobernación de Lattakia durante 1970-2016. Las tendencias anuales y estacionales para la temperatura y la precipitación se calcularon utilizando la prueba no paramétrica de Mann-Kendall. Las diferencias de medias entre los dos perÃodos (1970-2000) / (2001-2016) se evaluaron en los niveles anuales y estacionales mediante el uso de la prueba no paramétrica de Mann-Whitney U. Además, la aparición de valores extremadamente altos / bajos se analizó a nivel anual mediante el uso de la curva de distribución normal. El estudio encontró que los promedios anuales de temperatura aumentaron significativamente (p <0.05) en 0.22 ËšC / década y 0.17 ËšC \ década, en las estaciones de Lattakia y Hiffeh, respectivamente, durante 1970-2016. El verano reveló tendencias fuertes y significativas al alza (a nivel 0.01) en sus promedios de temperatura en 0.39 ËšC / década en Lattakia, y en 0.34 ËšC / década en Hiffeh. El promedio de precipitaciones de primavera disminuyó significativamente en -6.5 mm / década en Lattakia y en -12.1 mm / década en Hiffeh. La probabilidad de la aparición del valor de 20.2 ËšC o más como valor extremo aumentó en la estación de Lattakia durante 2001-2016 en un 40.8%.L’objectif de cette étude est d’analyser les changements dans les moyennes annuelles et saisonnières de la température de l’air et des précipitations sur la région du gouvernorat de Lattaquié entre 1970 et 2016. Les tendances annuelles et saisonnières de la température ont été calculées à l’aide du test non-paramétrique de Mann-Kendall. Les différences moyennes entre les périodes 1970-2000 et 2001-2016 ont été évaluées par année et saison en utilisant le test non-paramétrique de Mann-Whitney U. En ce qui concerne l’occurence de valeurs extrêmement élevées/ basses, celle-ci a été analysée sur une base annuelle en utilisant la courbe de distribution normale. L’étude a révélé que les températures moyennes annuelles (p<0,05) ont augmenté significativement de 0,22 ËšC / décennie et de 0,17 ËšC / décennie, dans les cas respectifs des stations de Lattakia et de Haffah durant la période 1970-2016. L’été a laissé voir une tendance marquée à la hausse (au niveau de 0,01) de ses moyennes de température : 0,39 ËšC / décennie à Lattaquié et 0,34 ËšC / décennie à Hiffeh. La moyenne des précipitations printanières a diminué de manière significative, soit de -6,5 mm / décennie à Lattakia et de -12,1 mm / décennie à Hiffeh. La probabilité d’apparition de la valeur de 20,2 ËšC ou plus comme valeur extrême a augmenté de 40,8% pour la station de Lattaquié pendant la période 2001-2016
Optimized Job Scheduling approach based on Genetic algorithms in smart Grid environment
The advances in communications and information technologies have been playing a major role in all aspects of our lives. One of those majors aspects that affect our daily lives is the power grids which lead to what we call Smart Grids. One of the major challenges in these grids is to optimize the consumption and resources. This paper presents an optimized job scheduling approach using genetic algorithm which provides a minimum cost for completing different tasks in a grid environment. In grid environment different independent appliances are sharing the same resources depending on the availability of resources and the need of these appliances to run. There are different job scheduling approached starting from typical strategies, Ant Colony (AC) and Genetic Algorithm (GA). In this paper we present a cost optimized Genetic Algorithm approach for appliances job scheduling by considering different parameters like job duration time, the resources availability and the job priority to start. The proposed approach is tested using a simulator written in c++ programming language. The results show that the total saving in cost is better than the previous approaches
Vehicle Speed Control Equipped with Special Combinations, Brake System and Safe Distance Measurements
Abstract: -It is a system that aims to control vehicle"s speed in accordance with the street and road speed limit. The system finds out the whereabouts of the vehicle then it identifies the allowed speed for that particular place. After this, it starts decreasing the speed gradually until it reaches the desirable limit. When the vehicle runs, The GPS finds the location of the vehicle then it sends the longitude and the latitude to the control unit to identify the speed limit of the street. If it has been found that the vehicle"s speed exceeds the limit, a signal will be sent to the brake system to reduce the speed until it drops to the limits. One of the most important characteristics of the system that it senses the distances between two vehicles by (Ultrasonic sensor) allowing a certain distance between them which is in correspondent to their speed and that results in non-occurrence of accidents and crashes. All of which is done without exceeding the speed limit of streets. If the system fails for any malfunction, a warning message containing the number of the vehicle and information about it will be sent to the traffic department as a feedback
A Heterogeneous Approach to Agile Tailoring
Self-organisation is recognised as one of the fundamental principles of Agile software development since the introduction of the Agile Manifesto. In large-scale agile, self- organising teams must cooperate to produce a software product jointly. Previous research has identified barriers to self-organising autonomous teams in large-scale agile, such as lack of guidelines for how teams should be organised, and other challenges related to building autonomous teams and aligning them. The Spotify model is an example of a very large-scale agile approach, which is driven by creating loosely coupled, yet tightly aligned squads. However, there is a conflicting trade-off between squads autonomy and alignment. Too much alignment might hinder squad autonomy, but without alignment, the squads are autonomous but are not effective.This research aims to (1) explore how Agile practitioners, from a FinTech organisation, resolve the conflicting trade-offs between squads autonomy and alignment, and (2) develop and evaluate new architectural governance practices, in a FinTech organisation tailoring the Spotify model. To address these aims, a qualitative research design was utilised. This research comprises two parts, a longitudinal embedded case study and an intervention embedded case study, which were conducted in a FinTech organisation (i.e., FinTechOrg).The longitudinal embedded case study lasted over 21 months, during which 225 ceremonies were observed, 14 semi-structured open-ended interviews were conducted, and data were collected from different sorts of artefacts. The collected data were analysed using an approach informed by the Grounded Theory method.The analysis identified influential factors on different aspects of Spotify Tailoring, which contribute to resolving the conflicting trade-offs between squads autonomy and alignment. These aspects are (1) establishing and building autonomous squads, (2) aligning autonomous squads, and (3) performing B2B product development by tailoring the Spotify model. The first contribution is identifying factors influencing establishing and building autonomous squads. The second contribution is identifying factors influencing aligning autonomous squads. The third contribution is identifying the impact of product development on Spotify tailoring as well as factors influencing Spotify Tailoring for B2B product development. Each identified factor is supported by a set of practices and attributes, which can aid Agile practitioners in improving squad autonomy, aligning autonomous squads, or facilitating the conduct of B2B product development.The fourth contribution is identifying a novel approach to Agile tailoring, called Heterogeneous Tailoring. Three key features characterise this approach. Firstly, each autonomous squad is empowered to select and tailor its development method. Secondly, each squad is aligned with other squads and to common product development goals and objectives. Thirdly, the product steering committee draws the strategy of squads’ missions and aligns the product backlog among autonomous squads. This novel approach to Agile tailoring has improved the creativity for some squads and increased the productivity for others, as reported by the practitioners of FinTechOrg.The Spotify model and the revealed Heterogeneous Tailoring approach do not provide practices or guidelines for governing Agile architecture across autonomous squads. Thus, an embedded case study intervention was conducted to contribute to facilitating Agile architecture governance. In this intervention, a novel approach to architectural governance was developed and evaluated in FinTechOrg, which is considered the last contribution. This approach incorporates a structural change and an architecture change management process. The intervention lasted 3 months, during which 32 ceremonies were observed and 8 semi-structured open-ended interviews were conducted. The collected data was analysed using an approach informed by the Grounded Theory method.Based on the results of the intervention, the Heterogeneous Tailoring approach was adapted to accommodate the novel approach to architectural governance. This adaptation has impacted the key features of the Heterogeneous Tailoring approach. Establishing autonomous squads was impacted by the introduced structural change. The alignment of autonomous squads was impacted by governing Agile architecture. Product development was impacted by the needs for planning architecture based user stories. Also, the adaptation of the Heterogeneous Tailoring approach revealed a new key feature, called Release Strategy, which is concerned with the continuous delivery of architecture enablers
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