332 research outputs found
Automated Experiments for Deriving Performance-relevant Properties of Software Execution Environments
The execution environment can play a crucial role when analyzing the performance of a software system. However, detecting execution environment properties and integrating such properties into performance analyses is a manual, error-prone task. In this thesis, a novel approach for detecting performance-relevant properties of the software execution environment is presented. These properties are automatically detected using predefined experiments and integrated into performance prediction tools
Secure and safe virtualization-based framework for embedded systems development
Tese de Doutoramento - Programa Doutoral em Engenharia Electrónica e de Computadores (PDEEC)The Internet of Things (IoT) is here. Billions of smart, connected devices are proliferating
at rapid pace in our key infrastructures, generating, processing and exchanging
vast amounts of security-critical and privacy-sensitive data. This strong connectivity
of IoT environments demands for a holistic, end-to-end security approach, addressing
security and privacy risks across different abstraction levels: device, communications,
cloud, and lifecycle managment.
Security at the device level is being misconstrued as the addition of features in a
late stage of the system development. Several software-based approaches such as
microkernels, and virtualization have been used, but it is proven, per se, they fail in
providing the desired security level. As a step towards the correct operation of these
devices, it is imperative to extend them with new security-oriented technologies
which guarantee security from the outset.
This thesis aims to conceive and design a novel security and safety architecture
for virtualized systems by 1) evaluating which technologies are key enablers for
scalable and secure virtualization, 2) designing and implementing a fully-featured
virtualization environment providing hardware isolation 3) investigating which "hard
entities" can extend virtualization to guarantee the security requirements dictated by
confidentiality, integrity, and availability, and 4) simplifying system configurability
and integration through a design ecosystem supported by a domain-specific language.
The developed artefacts demonstrate: 1) why ARM TrustZone is nowadays a reference
technology for security, 2) how TrustZone can be adequately exploited for
virtualization in different use-cases, 3) why the secure boot process, trusted execution
environment and other hardware trust anchors are essential to establish and
guarantee a complete root and chain of trust, and 4) how a domain-specific language
enables easy design, integration and customization of a secure virtualized
system assisted by the above mentioned building blocks.Vivemos na era da Internet das Coisas (IoT). Biliões de dispositivos inteligentes
começam a proliferar nas nossas infraestruturas chave, levando ao processamento
de avolumadas quantidades de dados privados e sensíveis. Esta forte conectividade
inerente ao conceito IoT necessita de uma abordagem holística, em que os riscos
de privacidade e segurança são abordados nas diferentes camadas de abstração:
dispositivo, comunicações, nuvem e ciclo de vida.
A segurança ao nível dos dispositivos tem sido erradamente assegurada pela inclusão
de funcionalidades numa fase tardia do desenvolvimento. Têm sido utilizadas diversas
abordagens de software, incluindo a virtualização, mas está provado que estas
não conseguem garantir o nível de segurança desejado. De forma a garantir a correta
operação dos dispositivos, é fundamental complementar os mesmos com novas tecnologias
que promovem a segurança desde os primeiros estágios de desenvolvimento.
Esta tese propõe, assim, o desenvolvimento de uma solução arquitetural inovadora
para sistemas virtualizados seguros, contemplando 1) a avaliação de tecnologias
chave que promovam tal realização, 2) a implementação de uma solução de virtualização
garantindo isolamento por hardware, 3) a identificação de componentes
que integrados permitirão complementar a virtualização para garantir os requisitos
de segurança, e 4) a simplificação do processo de configuração e integração da solução
através de um ecossistema suportado por uma linguagem de domínio específico.
Os artefactos desenvolvidos demonstram: 1) o porquê da tecnologia ARM TrustZone
ser uma tecnologia de referência para a segurança, 2) a efetividade desta tecnologia
quando utilizada em diferentes domínios, 3) o porquê do processo seguro de inicialização,
juntamente com um ambiente de execução seguro e outros componentes de
hardware, serem essenciais para estabelecer uma cadeia de confiança, e 4) a viabilidade
em utilizar uma linguagem de um domínio específico para configurar e integrar
um ambiente virtualizado suportado pelos artefactos supramencionados
Software development in the post-PC era : towards software development as a service
PhD ThesisEngineering software systems is a complex task which involves various stakeholders
and requires planning and management to succeed. As the role of software in our daily
life is increasing, the complexity of software systems is increasing. Throughout the
short history of software engineering as a discipline, the development practises and
methods have rapidly evolved to seize opportunities enabled by new technologies
(e.g., the Internet) and to overcome economical challenges (e.g., the need for cheaper
and faster development).
Today, we are witnessing the Post-PC era. An era which is characterised by mobility and
services. An era which removes organisational and geographical boundaries. An era
which changes the functionality of software systems and requires alternative methods
for conceiving them.
In this thesis, we envision to execute software development processes in the cloud.
Software processes have a software production aspect and a management aspect. To
the best of our knowledge, there are no academic nor industrial solutions supporting the
entire software development process life-cycle(from both production and management
aspects and its tool-chain execution in the cloud.
Our vision is to use the cloud economies of scale and leverage Model-Driven Engineering
(MDE) to integrate production and management aspects into the development
process. Since software processes are seen as workflows, we investigate using existing
Workflow Management Systems to execute software processes and we find that these
systems are not suitable. Therefore, we propose a reference architecture for Software
Development as a Service (SDaaS). The SDaaS reference architecture is the first proposal
which fully supports development of complex software systems in the cloud.
In addition to the reference architecture, we investigate three specific related challenges
and propose novel solutions addressing them. These challenges are:
Modelling & enacting cloud-based executable software processes. Executing
software processes in the cloud can bring several benefits to software develop
ment. In this thesis, we discuss the benefits and considerations of cloud-based
software processes and introduce a modelling language for modelling such processes.
We refer to this language as EXE-SPEM. It extends the Software and Systems
Process Engineering (SPEM2.0) OMG standard to support creating cloudbased
executable software process models. Since EXE-SPEM is a visual modelling
language, we introduce an XML notation to represent EXE-SPEM models
in a machine-readable format and provide mapping rules from EXE-SPEM to
this notation. We demonstrate this approach by modelling an example software
process using EXE-SPEM and mapping it to the XML notation. Software process
models expressed in this XML format can then be enacted in the proposed SDaaS
architecture.
Cost-e cient scheduling of software processes execution in the cloud. Software
process models are enacted in the SDaaS architecture as workflows. We
refer to them sometimes as Software Workflows. Once we have executable software
process models, we need to schedule them for execution. In a setting where
multiple software workflows (and their activities) compete for shared computational
resources (workflow engines), scheduling workflow execution becomes
important. Workflow scheduling is an NP-hard problem which refers to the allocation
of su cient resources (human or computational) to workflow activities.
The schedule impacts the workflow makespan (execution time) and cost as well as
the computational resources utilisation. The target of the scheduling is to reduce
the process execution cost in the cloud without significantly a ecting the process
makespan while satisfying the special requirements of each process activity (e.g.,
executing on a private cloud). We adapt three workflow scheduling algorithms
to fit for SDaaS and propose a fourth one; the Proportional Adaptive Task Schedule.
The algorithms are then evaluated through simulation. The simulation results
show that the our proposed algorithm saves between 19.74% and 45.78% of the
execution cost, provides best resource (VM) utilisation and provides the second
best makespan compared to the other presented algorithms.
Evaluating the SDaaS architecture using a case study from the safety-critical
systems domain. To evaluate the proposed SDaaS reference architecture, we
instantiate a proof-of-concept implementation of the architecture. This imple
mentation is then used to enact safety-critical processes as a case study.
Engineering safety-critical systems is a complex task which involves multiple
stakeholders. It requires shared and scalable computation to systematically involve
geographically distributed teams. In this case study, we use EXE-SPEM to
model a portion of a process (namely; the Preliminary System Safety Assessment
- PSSA) adapted from the ARP4761 [2] aerospace standard. Then, we enact this
process model in the proof-of-concept SDaaS implementation.
By using the SDaaS architecture, we demonstrate the feasibility of our approach
and its applicability to di erent domains and to customised processes. We also
demonstrate the capability of EXE-SPEM to model cloud-based executable processes.
Furthermore, we demonstrate the added value of the process models and
the process execution provenance data recorded by the SDaaS architecture. This
data is used to automate the generation of safety cases argument fragments. Thus,
reducing the development cost and time. Finally, the case study shows that we
can integrate some existing tools and create new ones as activities used in process
models.
The proposed SDaaS reference architecture (combined with its modelling, scheduling
and enactment capabilities) brings the benefits of the cloud to software development. It
can potentially save software production cost and provide an accessible platform that
supports collaborating teams (potentially across di erent locations). The executable
process models support unified interpretation and execution of processes across team(s)
members. In addition, the use of models provide managers with global awareness and
can be utilised for quality assurance and process metrics analysis and improvement.
We see the contributions provided in this thesis as a first step towards an alternative
development method that uses the benefits of cloud and Model-Driven Engineering to
overcome existing challenges and open new opportunities. However, there are several
challenges that are outside the scope of this study which need to be addressed to allow
full support of the SDaaS vision (e.g., supporting interactive workflows). The solutions
provided in this thesis address only part of a bigger vision. There is also a need for
empirical and usability studies to study the impact of the SDaaS architecture on both
the produced products (in terms of quality, cost, time, etc.) and the participating
stakeholders
Smart manufacturing scheduling: A literature review
[EN] Within the scheduling framework, the potential of digital twin (DT) technology, based on virtualisation and intelligent algorithms to simulate and optimise manufacturing, enables an interaction with processes and modifies their course of action in time synchrony in the event of disruptive events. This is a valuable capability for automating scheduling and confers it autonomy. Automatic and autonomous scheduling management can be encouraged by promoting the elimination of disruptions due to the appearance of defects, regardless of their origin. Hence the zero-defect manufacturing (ZDM) management model oriented towards zero-disturbance and zero-disruption objectives has barely been studied. Both strategies combine the optimisation of production processes by implementing DTs and promoting ZDM objectives to facilitate the modelling of automatic and autonomous scheduling systems. In this context, this particular vision of the scheduling process is called smart manufacturing scheduling (SMS). The aim of this paper is to review the existing scientific literature on the scheduling problem that considers the DT technology approach and the ZDM model to achieve self-management and reduce or eliminate the need for human intervention. Specifically, 68 research articles were identified and analysed. The main results of this paper are to: (i) find methodological trends to approach SMS models, where three trends were identified; i.e. using DT technology and the ZDM model, utilising other enabling digital technologies and incorporating inherent SMS capabilities into scheduling; (ii) present the main SMS alignment axes of each methodological trend; (iii) provide a map to classify the literature that comes the closest to the SMS concept; (iv) discuss the main findings and research gaps identified by this study. Finally, managerial implications and opportunities for further research are identified.This work was supported by the Spanish Ministry of Science, Innovation and Universities project entitled 'Optimisation of zero-defects production technologies enabling supply chains 4.0 (CADS4.0) ' (RTI2018-101344-B-I00) , the European Union H2020 research and innovation programme with grant agreement No. 825631 "Zero Defect Manufacturing Platform (ZDMP) " and the European Union H2020 research and innovation programme with agreement No. 958205 "In-dustrial Data Services for Quality Control in Smart Manufacturing (i4Q) ".Serrano-Ruiz, JC.; Mula, J.; Poler, R. (2021). Smart manufacturing scheduling: A literature review. Journal of Manufacturing Systems. 61:265-287. https://doi.org/10.1016/j.jmsy.2021.09.0112652876
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