Analysing dependability and performance of a real-world Elastic Search application

—Increased complexity in IT, big data, and advanced analytical techniques are some of the trends driving demand for more sophisticated and scalable search technology. Despite Quality of Service (QoS) being a critical success factor in most enterprise software service offerings, it is often not a generic component of the enterprise search software stack. In this paper, we explore enterprise search engine dependability and performance using a real-world company architecture and associated data sourced from an ElasticSearch implementation on Linknovate.com. We propose a Fault Tree model to assess the availability and reliability of the Linknovate.com architecture. The results of the Fault Tree model are fed into a Stochastic Petri Net (SPN) model to analyze how failures and redundancy impact application performance of the use case system. Availability and MTTF were used to evaluate the reliability and throughput was used to evaluate the performance of the target system. The best results for all three metrics were returned in scenarios with high levels of redundancy

How premium brands should do to upgrade and move to a luxury status: The case of three Portuguese brands that successfully migrated from premium to luxury: Claus Porto, Josefinas and Vila Joya

Premium brands’ upgrade process to luxury is a phenomenon still not well analysed. A literature review allowed assessment of what distinguishes premium and luxury brands. We infered five propositions then tested through a case study research. The research investigated three Portuguese brands that successfully moved from premium to luxury - Claus Porto, Josefinas and Vila Joya. We conclude that acquiring social status is the most essential and difficult feature to deal with, when migrating from premium to luxury as it depends on voluntary and involuntary factors

A Survey and Taxonomy of Self-Aware and Self-Adaptive Cloud Autoscaling Systems

Autoscaling system can reconfigure cloud-based services and applications, through various configurations of cloud software and provisions of hardware resources, to adapt to the changing environment at runtime. Such a behavior offers the foundation for achieving elasticity in a modern cloud computing paradigm. Given the dynamic and uncertain nature of the shared cloud infrastructure, the cloud autoscaling system has been engineered as one of the most complex, sophisticated, and intelligent artifacts created by humans, aiming to achieve self-aware, self-adaptive, and dependable runtime scaling. Yet the existing Self-aware and Self-adaptive Cloud Autoscaling System (SSCAS) is not at a state where it can be reliably exploited in the cloud. In this article, we survey the state-of-the-art research studies on SSCAS and provide a comprehensive taxonomy for this field. We present detailed analysis of the results and provide insights on open challenges, as well as the promising directions that are worth investigated in the future work of this area of research. Our survey and taxonomy contribute to the fundamentals of engineering more intelligent autoscaling systems in the cloud

Simulating fog and edge computing scenarios: an overview and research challenges

The fourth industrial revolution heralds a paradigm shift in how people, processes, things, data and networks communicate and connect with each other. Conventional computing infrastructures are struggling to satisfy dramatic growth in demand from a deluge of connected heterogeneous endpoints located at the edge of networks while, at the same time, meeting quality of service levels. The complexity of computing at the edge makes it increasingly difficult for infrastructure providers to plan for and provision resources to meet this demand. While simulation frameworks are used extensively in the modelling of cloud computing environments in order to test and validate technical solutions, they are at a nascent stage of development and adoption for fog and edge computing. This paper provides an overview of challenges posed by fog and edge computing in relation to simulation

Calidad de servicio en computación en la nube: técnicas de modelado y sus aplicaciones

Recent years have seen the massive migration of enterprise applications to the cloud. One of the challenges posed by cloud applications is Quality-of-Service (QoS) management, which is the problem of allocating resources to the application to guarantee a service level along dimensions such as performance, availability and reliability. This paper aims at supporting research in this area by providing a survey of the state of the art of QoS modeling approaches suitable for cloud systems. We also review and classify their early application to some decision-making problems arising in cloud QoS management

Understanding stress : a focus on executive functions in Saudi Arabia : an exploratory study

The dissertation brings together and reports the entire work presented and discussed throughout this pioneering and original research project. This exploratory study utilising primarily semi-structured, qualitative research methodology aimed to develop a model of executive stress by discovering, understanding, describing and sharing knowledge and experience of occupational stress caused by the basic executive functions, among the oil and gas executives in Saudi Arabia. These functions included planning, organising, leading and controlling. This interpretive investigation involved forty-three executives of five major oil and gas firms in Saudi Arabia purposively selected for participation in this exploratory study through audiotape-recorded interviews gathered over a period of eight months from June 2002 to January 2003. In addition, this primary data collection method was triangulated with other secondary methods of observations, focus groups and documentary analysis involving additional twenty executives from other neighboured Arabian Gulf countries. These considerable qualitative data were systematically managed through primarily manual analysis along with the aid of NUD*IST qualitative analysis computer program.Common recurring categories, themes and patterns were identified in relation to sources of stress, manifestations and coping strategies along with stressful factors related to internal and external environments. The study findings revealed four significant interrelated eustressful and distressful themes underpinning the basic executive functions of planning, organising, leading and controlling. These were related to information management, performance management, human resource management and strategic management. The findings revealed that the participants perceived these focused executive functions as a direct source of occupational stress instead of the basic executive functions that were thought of at the beginning of the research. The emerged key patterns related to these focused activities included difficulty of people management, micromanagement behaviour and engineering attitude. Moreover, the study resulted into additional stress factors related to the organisational structure and work style of the internal environment of the organisation. There were also other stressful contributing factors associated with Government interventions, market influences, media focus and social conflict of the external environment of the organisation. Furthermore, the study revealed important personal related factors that could shape and regulate the manifestations of executive eustress or distress. These included experience, personality type, cognitive appraisal and self-esteem factors.Accordingly, a comprehensive framework of executive stress process based on a dynamic system approach was developed summarising the explored executive stress process and its underlying attributes. This present qualitative study was designed interpretively and qualitatively for exploration or discovery of the topic under investigation. Further, the limitations of this approach were acknowledged, as being subjective perceptions, understandings and descriptions of the oil and gas executives under investigation.In view of that, this new and original study was hoped to add to the existing knowledge in various related areas such as occupational health and safety, industrial/ organisational psychology, human resource management, strategic management and organisational culture. This research could add value to the field of occupational stress in Arabic context in particular and the world in general since there was little research about the types and effects of job-related stress at the time of the study

Dynamic Multiparty Authentication of Data Analytics Services within Cloud Environments

Business analytics processes are often composed from orchestrated, collaborating services, which are consumed by users from multiple cloud systems (in different security realms), which need to be engaged dynamically at runtime. If heterogeneous cloud systems located in different security realms do not have direct authentication relationships, then it is a considerable technical challenge to enable secure collaboration. In order to address this security challenge, a new authentication framework is required to establish trust amongst business analytics service instances and users by distributing a common session secret to all participants of a session. We address this challenge by designing and implementing a secure multiparty authentication framework for dynamic interaction, for the scenario where members of different security realms express a need to access orchestrated services. This novel framework exploits the relationship of trust between session members in different security realms, to enable a user to obtain security credentials that access cloud resources in a remote realm. The mechanism assists cloud session users to authenticate their session membership, thereby improving the performance of authentication processes within multiparty sessions. We see applicability of this framework beyond multiple cloud infrastructure, to that of any scenario where multiple security realms has the potential to exist, such as the emerging Internet of Things (IoT).Comment: Submitted to the 20th IEEE International Conference on High Performance Computing and Communications 2018 (HPCC2018), 28-30 June 2018, Exeter, U