Multi-tenancy in cloud computing

As Cloud Computing becomes the trend of information technology computational model, the Cloud security is becoming a major issue in adopting the Cloud where security is considered one of the most critical concerns for the large customers of Cloud (i.e. governments and enterprises). Such valid concern is mainly driven by the Multi-Tenancy situation which refers to resource sharing in Cloud Computing and its associated risks where confidentiality and/or integrity could be violated. As a result, security concerns may harness the advancement of Cloud Computing in the market. So, in order to propose effective security solutions and strategies a good knowledge of the current Cloud implementations and practices, especially the public Clouds, must be understood by professionals. Such understanding is needed in order to recognize attack vectors and attack surfaces. In this paper we will propose an attack model based on a threat model designed to take advantage of Multi-Tenancy situation only. Before that, a clear understanding of Multi-Tenancy, its origin and its benefits will be demonstrated. Also, a novel way on how to approach Multi-Tenancy will be illustrated. Finally, we will try to sense any suspicious behavior that may indicate to a possible attack where we will try to recognize the proposed attack model empirically from Google trace logs. Google trace logs are a 29-day worth of data released by Google. The data set was utilized in reliability and power consumption studies, but not been utilized in any security study to the extent of our knowledge

Tenant-centric Sub-Tenancy Architecture in Software-as-a-Service

AbstractMulti-tenancy architecture (MTA) is often used in Software-as-a-Service (SaaS) and the central idea is that multiple tenant applications can be developed using components stored in the SaaS infrastructure. Recently, MTA has been extended to allow a tenant application to have its own sub-tenants, where the tenant application acts like a SaaS infrastructure. In other words, MTA is extended to STA (Sub-Tenancy Architecture). In STA, each tenant application needs not only to develop its own functionalities, but also to prepare an infrastructure to allow its sub-tenants to develop customized applications. This paper applies Crowdsourcing as the core to STA component in the development life cycle. In addition, to discovering adequate fit tenant developers or components to help build and compose new components, dynamic and static ranking models are proposed. Furthermore, rank computation architecture is presented to deal with the case when the number of tenants and components becomes huge. Finally, experiments are performed to demonstrate that the ranking models and the rank computation architecture work as design

On the Extensibility of Formal Methods Tools

Modern software systems often have long lifespans over which they must continually evolve to meet new, and sometimes unforeseen, requirements. One way to effectively deal with this is by developing the system as a series of extensions. As requirements change, the system evolves through the addition of new extensions and, potentially, the removal of existing extensions. In order for this kind of development process to thrive, it is necessary that the system have a high level of extensibility. Extensibility is the capability of a system to support the gradual addition of new, unplanned functionalities. This dissertation investigates extensibility of software systems and focuses on a particular class of software: formal methods tools. The approach is broad in scope. Extensibility of systems is addressed in terms of design, analysis and improvement, which are carried out in terms of source code and software architecture. For additional perspective, extensibility is also considered in the context of formal modelling. The work carried out in this dissertation led to the development of various extensions to the Overture tool supporting the Vienna Development Method, including a new proof obligation generator and integration with theorem provers. Additionally, the extensibility of Overture itself was also improved and it now better supports the development and integration of various kinds of extensions. Finally, extensibility techniques have been applied to formal modelling, leading to an extensible architectural style for formal models

PaaS manager : a platform-as-a-service aggregation framework

The advent of Cloud Computing opened new opportunities in several areas, namely in the application development processes. As consequence, nowadays, PaaS (Platform-as-a-Service) service model allows simpler and flexible deployment strategies of applications, avoiding the need for dedicated networks, servers, stor- age, and other services. Within this context, several PaaS providers exist in the market, but each one having specific characteristics, proprietary technologies and Application Programming Interfaces (APIs). Based on such assumptions, this work addresses the challenge of devising a PaaS aggregation solution with the objective of unifying the information and management processes of applications created in PaaS environments. The proposed solution, denominated as PaaS Manager, take the form of a PaaS API aggregator aiming to struggle the existing lock-in in the PaaS market. In this perspective, this paper describes the specification, development and test of the proposed PaaS Manager solution. As result of this framework, end-users are able to select the most appropriate PaaS platform for an application, interacting with any supported vendor through a unique deployment and management interface.This work has been supported by FCT - Fundação para a Ciência e a Tecnologia within the Project Scope: PEst-OE/EEI/UI0319/2014

Robust Contract Evolution in a TypeSafe MicroServices Architecture

Microservices architectures allow for short deployment cycles and immediate effects but offer no safety mechanisms when service contracts need to be changed. Maintaining the soundness of microservice architectures is an error-prone task that is only accessible to the most disciplined development teams. We present a microservice management system that statically verifies service interfaces and supports the seamless evolution of compatible interfaces. We define a compatibility relation that captures real evolution patterns and embodies known good practices on the evolution of interfaces. Namely, we allow for the addition, removal, and renaming of data fields of a producer module without breaking or needing to upgrade consumer services. The evolution of interfaces is supported by runtime generated proxy components that dynamically adapt data exchanged between services to match with the statically checked service code.The model was instantiated in a core language whose semantics is defined by a labeled transition system and a type system that prevents breaking changes from being deployed. Standard soundness results for the core language entail the existence of adapters, hence the absence of adaptation errors and the correctness of the management model. This adaptive approach allows for gradual deployment of modules, without halting the whole system and avoiding losing or misinterpreting data exchanged between system nodes. Experimental data shows that an average of 69% of deployments that would require adaptation and recompilation are safe under our approach

Barriers to the adoption of digital twin in the construction industry : a literature review

Digital twin (DT) has gained significant recognition among researchers due to its potential across industries. With the prime goal of solving numerous challenges confronting the construction industry (CI), DT in recent years has witnessed several applications in the CI. Hence, researchers have been advocating for DT adoption to tackle the challenges of the CI. Notwithstanding, a distinguishable set of barriers that oppose the adoption of DT in the CI has not been determined. Therefore, this paper identifies the barriers and incorporates them into a classified framework to enhance the roadmap for adopting DT in the CI. This research conducts an extensive review of the literature and analyses the barriers whilst integrating the science mapping technique. Using Scopus, ScienceDirect, and Web of Science databases, 154 related bibliographic records were identified and analysed using science mapping, while 40 carefully selected relevant publications were systematically reviewed. From the review, the top five barriers identified include low level of knowledge, low level of technology acceptance, lack of clear DT value propositions, project complexities, and static nature of building data. The results show that the UK, China, the USA, and Germany are the countries spearheading the DT adoption in the CI, while only a small number of institutions from Australia, the UK, Algeria, and Greece have established institutional collaborations for DT research. A conceptual framework was developed on the basis of 30 identified barriers to support the DT adoption roadmap. The main categories of the framework comprise stakeholder-oriented, industryrelated, construction-enterprise-related, and technology-related barriers. The identified barriers and the framework will guide and broaden the knowledge of DT, which is critical for successful adoption in the construction industry

Low Effort and Privacy – How Textual Priming Affects Privacy Concerns of Email Service Users

The integration of digital applications and systems into the everyday routines of users is inevitably progressing. Ubiquitous and invisible computing requires the perspective of a new user and the inclusion of insights from related disciplines such as behavioral economics or social psychology. This paper takes up the call for research by Dinev et al. (2015) and examines the influence of textual priming elements on the privacy concerns of users of email accounts. The paper provides an operationalization of a privacy concern as a dependent variable, incorporated in an online experiment with 276 participants. The results show highly significant differences between the groups investigated by the experiment. Specifically, the users of different email providers show interesting results. While users of Gmail show no significant reaction in the experiment, users of other email providers show significant differences in the experimental setting

Arquitecturas software y herramientas de modelado para la integración del procesamiento de eventos complejos y blockchain

Blockchain es una tecnología de vanguardia que proporciona un libro de contabilidad distribuido e inmutable para almacenar transacciones, garantizando la seguridad, fiabilidad, trazabilidad, inmutabilidad y transparencia de la información. El comportamiento de la blockchain puede programarse mediante contratos inteligentes, que pueden utilizarse para especificar acuerdos entre distintas partes en tiempo de diseño y para validar el cumplimiento de las condiciones acordadas en tiempo de ejecución. Sin embargo, la implementación y gestión de contratos inteligentes es una tarea difícil no solo para expertos en la materia, sino también para desarrolladores de software, ya que requiere conocimientos avanzados de lenguajes de propósito específico como Solidity. Además, este lenguaje no soporta directamente la definición de reglas de negocio con correlación temporal de eventos y tiene restricciones en cuanto a los tipos de valores y su longitud. Las malas prácticas en la programación de contratos inteligentes pueden generar fallos o vulnerabilidades, provocando pérdidas económicas. Cualquier intento de ataque, por ejemplo, tratando de manipular los datos de la blockchain también puede causar errores y otras anomalías en la red blockchain. No obstante, detectar este tipo de situaciones de interés en tiempo real o comprobar automáticamente situaciones anómalas dentro de la red blockchain es actualmente un hándicap. Para dar respuesta a todos estos problemas, esta tesis doctoral en forma de compendio de artículos, titulada "Arquitecturas software y herramientas de modelado para la integración del procesamiento de eventos complejos y blockchain", aborda el reto de integrar las tecnologías de blockchain y el procesamiento de eventos complejos (Complex Event Processing, CEP). CEP es una tecnología potente que permite analizar y correlacionar grandes volúmenes de datos con el fin de detectar automáticamente patrones de interés en tiempo real. El objetivo principal de esta tesis doctoral es el desarrollo de arquitecturas software (centralizadas, distribuidas y contenerizadas) y herramientas de modelado para dar soporte a la integración de CEP y blockchain. Para lograr este objetivo, se han elaborado estudios del estado del arte y se han diseñado, implementado y probado arquitecturas y herramientas de modelado para la integración de CEP y blockchain. Estas herramientas permiten, entre otras cosas, la monitorización en tiempo real de los datos generados en las redes blockchain y la detección automática de anomalías en estas redes mediante patrones de eventos, la invocación automática de contratos inteligentes cuando se cumplen las condiciones de los patrones de eventos, así como la gestión de contratos inteligentes de forma amigable. Esta integración se ha logrado a través de soluciones ligeras y portables, y eliminando las engorrosas tareas de configuración a la hora de desplegarlas y utilizarlas, facilitando así la interacción y uso por parte de expertos en el dominio de aplicación, pero no en las tecnologías.Blockchain is a cutting-edge technology that provides a distributed and immutable ledger for storing transactions, ensuring security, reliability, traceability, immutability and transparency of information. The behavior of the blockchain can be programmed by means of smart contracts, which can be used to specify agreements between different parties at design time and to validate compliance with agreed conditions at runtime. However, the implementation and management of smart contracts is a difficult task not only for experts in the field, but also for software developers, as it requires advanced knowledge of specific-purpose languages such as Solidity. Moreover, this language does not directly support the possibility of defining business rules with temporal correlation of events and has restrictions on the types of values and their length. Bad practices in smart contract programming can generate bugs or vulnerabilities causing economic losses. Any attack attempt, for example, trying to manipulate the blockchain data can also cause errors and other anomalies in the blockchain network. Nevertheless, detecting this type of situations of interest in real time or automatically checking anomalous situations within the blockchain network is currently a handicap. To alleviate all these problems, this doctoral thesis in the form of a compendium of papers, entitled "Software architectures and modeling tools for integrating complex event processing and blockchain", addresses the challenge of integrating blockchain and Complex Event Processing (CEP) technologies. CEP is a powerful technology that allows analyzing and correlating large volumes of data with the purpose of automatically detecting patterns of interest in real time. The main objective of this doctoral thesis is the development of software architectures (centralized, distributed and containerized) and modeling tools to support the integration of CEP and blockchain. To achieve this goal, state-of-the-art studies have been carried out as well as the design, implementation and testing of architectures and modeling tools for integrating CEP and blockchain. These tools allow, among other things, the real-time monitoring of data generated in blockchain networks and the automatic detection of anomalies in these networks by matching event patterns, the automatic invocation of smart contracts when event pattern conditions are satisfied, as well as the smart contract management in a user-friendly way. This integration has been achieved through lightweight and portable solutions, and eliminating the cumbersome configuration tasks when deploying and operating them, thus facilitating the interaction and use by experts in the application domain, but not in the technologies

Artificial Collective Intelligence Engineering: a Survey of Concepts and Perspectives

Collectiveness is an important property of many systems--both natural and artificial. By exploiting a large number of individuals, it is often possible to produce effects that go far beyond the capabilities of the smartest individuals, or even to produce intelligent collective behaviour out of not-so-intelligent individuals. Indeed, collective intelligence, namely the capability of a group to act collectively in a seemingly intelligent way, is increasingly often a design goal of engineered computational systems--motivated by recent techno-scientific trends like the Internet of Things, swarm robotics, and crowd computing, just to name a few. For several years, the collective intelligence observed in natural and artificial systems has served as a source of inspiration for engineering ideas, models, and mechanisms. Today, artificial and computational collective intelligence are recognised research topics, spanning various techniques, kinds of target systems, and application domains. However, there is still a lot of fragmentation in the research panorama of the topic within computer science, and the verticality of most communities and contributions makes it difficult to extract the core underlying ideas and frames of reference. The challenge is to identify, place in a common structure, and ultimately connect the different areas and methods addressing intelligent collectives. To address this gap, this paper considers a set of broad scoping questions providing a map of collective intelligence research, mostly by the point of view of computer scientists and engineers. Accordingly, it covers preliminary notions, fundamental concepts, and the main research perspectives, identifying opportunities and challenges for researchers on artificial and computational collective intelligence engineering.Comment: This is the author's final version of the article, accepted for publication in the Artificial Life journal. Data: 34 pages, 2 figure