A Framework for Service-Oriented Architecture (SOA)-Based IoT Application Development

Funding: This research was partially supported by funds provided by the European Commission in the scope of FoF/H2020-723710 vf-OS, ICT/H2020-825631 ZDMP projects, and by the FCT— Fundação para a Ciência e a Tecnologia in the scope of UIDB/00066/2020 related to CTS—Centro de Tecnologia e Sistemas research unit.In the last decades, the increasing complexity of industrial information technology has led to the emergence of new trends in manufacturing. Factories are using multiple Internet of Things (IoT) platforms to harvest sensor information to improve production. Such a transformation contributes to efficiency growth and reduced production costs. To deal with the heterogeneity of the services within an IoT system, Service-Oriented Architecture (SOA) is referred to in the literature as being advantageous for the design and development of software to support IoT-based production processes.The aim of SOA-based design is to provide the leverage to use and reuse loosely coupled IoT services at the middleware layer to minimise system integration problems. We propose a system architecture that follows the SOA architectural pattern and enables developers and business process designers to dynamically add, query or use instances of existing modular software in the IoT context. Furthermore, an analysis of utilization of modular software that presents some challenges and limitations of this approach is also in the scope of this workpublishersversionpublishe

Machine Tool Communication (MTComm) Method and Its Applications in a Cyber-Physical Manufacturing Cloud

The integration of cyber-physical systems and cloud manufacturing has the potential to revolutionize existing manufacturing systems by enabling better accessibility, agility, and efficiency. To achieve this, it is necessary to establish a communication method of manufacturing services over the Internet to access and manage physical machines from cloud applications. Most of the existing industrial automation protocols utilize Ethernet based Local Area Network (LAN) and are not designed specifically for Internet enabled data transmission. Recently MTConnect has been gaining popularity as a standard for monitoring status of machine tools through RESTful web services and an XML based messaging structure, but it is only designed for data collection and interpretation and lacks remote operation capability. This dissertation presents the design, development, optimization, and applications of a service-oriented Internet-scale communication method named Machine Tool Communication (MTComm) for exchanging manufacturing services in a Cyber-Physical Manufacturing Cloud (CPMC) to enable manufacturing with heterogeneous physically connected machine tools from geographically distributed locations over the Internet. MTComm uses an agent-adapter based architecture and a semantic ontology to provide both remote monitoring and operation capabilities through RESTful services and XML messages. MTComm was successfully used to develop and implement multi-purpose applications in in a CPMC including remote and collaborative manufacturing, active testing-based and edge-based fault diagnosis and maintenance of machine tools, cross-domain interoperability between Internet-of-things (IoT) devices and supply chain robots etc. To improve MTComm’s overall performance, efficiency, and acceptability in cyber manufacturing, the concept of MTComm’s edge-based middleware was introduced and three optimization strategies for data catching, transmission, and operation execution were developed and adopted at the edge. Finally, a hardware prototype of the middleware was implemented on a System-On-Chip based FPGA device to reduce computational and transmission latency. At every stage of its development, MTComm’s performance and feasibility were evaluated with experiments in a CPMC testbed with three different types of manufacturing machine tools. Experimental results demonstrated MTComm’s excellent feasibility for scalable cyber-physical manufacturing and superior performance over other existing approaches

Machine Tool Communication (MTComm) Method and Its Applications in a Cyber-Physical Manufacturing Cloud

The integration of cyber-physical systems and cloud manufacturing has the potential to revolutionize existing manufacturing systems by enabling better accessibility, agility, and efficiency. To achieve this, it is necessary to establish a communication method of manufacturing services over the Internet to access and manage physical machines from cloud applications. Most of the existing industrial automation protocols utilize Ethernet based Local Area Network (LAN) and are not designed specifically for Internet enabled data transmission. Recently MTConnect has been gaining popularity as a standard for monitoring status of machine tools through RESTful web services and an XML based messaging structure, but it is only designed for data collection and interpretation and lacks remote operation capability. This dissertation presents the design, development, optimization, and applications of a service-oriented Internet-scale communication method named Machine Tool Communication (MTComm) for exchanging manufacturing services in a Cyber-Physical Manufacturing Cloud (CPMC) to enable manufacturing with heterogeneous physically connected machine tools from geographically distributed locations over the Internet. MTComm uses an agent-adapter based architecture and a semantic ontology to provide both remote monitoring and operation capabilities through RESTful services and XML messages. MTComm was successfully used to develop and implement multi-purpose applications in in a CPMC including remote and collaborative manufacturing, active testing-based and edge-based fault diagnosis and maintenance of machine tools, cross-domain interoperability between Internet-of-things (IoT) devices and supply chain robots etc. To improve MTComm’s overall performance, efficiency, and acceptability in cyber manufacturing, the concept of MTComm’s edge-based middleware was introduced and three optimization strategies for data catching, transmission, and operation execution were developed and adopted at the edge. Finally, a hardware prototype of the middleware was implemented on a System-On-Chip based FPGA device to reduce computational and transmission latency. At every stage of its development, MTComm’s performance and feasibility were evaluated with experiments in a CPMC testbed with three different types of manufacturing machine tools. Experimental results demonstrated MTComm’s excellent feasibility for scalable cyber-physical manufacturing and superior performance over other existing approaches

Gestão Dinâmica de Micro-serviços na Cloud/Edge

Observa-se, hoje em dia, um crescimento muito elevado da utilização de dispositivos no domínio da Internet of Things (IoT) e de dispositivos móveis, bem como do número de aplicações com consumo elevado de largura de banda (ex.: visualização de vídeos, a pedido). Tal implica que, num futuro próximo, não será viável suportar a quantidade de dados transferidos entre os dispositivos clientes ("end devices") e os centros de dados cloud, onde tipicamente são alojadas aplicações de acesso ubíquo. O problema do consequente aumento da latência percebido nas aplicações clientes, é ainda agravado no caso de aplicações "sensíveis à latência" (latency sensitive), como sejam aplicações bastante interativas ou de tempo real/quase-real (ex.: carros autonómicos, jogos online, etc.). A localização deste tipo de aplicações na cloud, onde é grande a distância entre os clientes e a localização dos centros de dados, resulta em níveis inaceitáveis de Quality of Service (QoS) percebida pelos clientes, ou mesmo a impossibilidade de cumprir os requisitos funcionais das aplicações. A computação na edge (Edge computing) surge como resposta aos problemas de latência referidos, ao usar recursos computacionais dos dispositivos na periferia da rede, que se situam mais próximo das aplicações cliente. É ainda possível realizar computações que filtrem os dados gerados na periferia, contribuindo para diminuir o volume de dados em trânsito, e que teriam de ser processados na cloud. Comparativamente com os recursos presentes nos centros de dados cloud, os recursos dos nós na edge são, no entanto, de capacidade computacional bastante limitada. Isto implica que utilizar aplicações monolíticas (tipicamente de grandes dimensões) não é uma opção eficaz na computação na edge, quer pelo custo da sua migração/replicação, quer pela impossibilidade de alojar as aplicações nesses nós. O uso da arquitetura de micro-serviços permite contribuir para a resolução deste problema. As aplicações são compostas por múltiplos micro-serviços, cada um com pequena dimensão, oferecendo uma funcionalidade única, com interfaces bem definidas e que comunicam entre si através de mensagens, tornando-os independentes entre si. Desta forma, é possível realizar uma gestão mais eficaz dos recursos disponíveis nos nós periféricos. O trabalho que se procura resolver relaciona-se com os problemas inerentes a um gestor centralizado quando temos um domínio muito dinâmico, o que inclui quer a infraestrutura, quer as aplicações variadas que são lançadas nesses nós, quer a grande volatilidade e diversidade nos acessos por parte dos clientes. Foi desenvolvida uma solução de um gestor distribuído, com arquitetura hierárquica, de um conjunto de nós e serviços no ambiente cloud/edge, incluindo a necessidade de efetuar melhoramentos adicionais à solução existente. A hierarquia de gestores distribuídos permitiu distribuir a responsabilidade e trabalho, ao reduzir a região geográfica abrangida por cada gestor, reduzindo assim a distância de comunicação entre os nós que cada um controla.There is nowadays a very high growth in the use of devices in the domain of IoT and mobile devices, as well as the number of applications with high bandwidth consumption (e.g. video on-demand). This implies that in the near future it will not be feasible to support the amount of data transferred between end devices and data centers, where ubiquitous access applications are typically hosted. The problem of the consequent increase in perceived latency in client applications is further aggravated in the case of latency-sensitive applications, such as very interactive or real-time applications (e.g. autonomic cars, online games, etc.). The location of this type of cloud applications, where the distance between customers and the location of data centers is large, results in unacceptable levels of QoS perceived by customers, or even the impossibility of meeting the functional requirements of such applications. Edge computing emerges as a response to the latency problems referred to by using computing resources of the devices at the edge of the network, which are closer to the client applications. It is also possible to perform computations that filter the data generated in the edge, contributing to decrease the volume of data in transit, that would have to be otherwise processed in the cloud. Compared with the resources available in the cloud data centers, the resources of the nodes in the edge are, however, of very limited computational capacity. This implies that using monolithic (typically large) applications is not an efficient choice in edge computing, either because of the cost of its migration/replication or because it is impossible to host the applications on those nodes. The use of the micro-services architecture seeks to solve this problem. The applications are composed of multiple micro-services, each with a small dimension, offering a unique functionality, with well-defined interfaces that communicate with each other through messages, making them independent of each other. In this way, it is possible to perform a more efficient management of the available resources in the edge devices. This work looks to solve problems related to a centralized manager on a very dynamic domain, including the infrastructure, multiple heterogeneous aplications launched on the system nodes, and the diversity and volatibility of the users. The prototype consists of a hierarchy of distributed managers of nodes and services in the cloud/edge environment, including the necessity of doing aditional improvements of the existing work. The hierarchy of distributed managers allows the distribution of work and resposabilities between managers and the reduction of the geographical area managed by one particular manager, which implies a lesser distance of communication between nodes