Protótipo Ciber-Físico de Elevador Monta-Cargas

Nesta dissertação foi proposto o desenvolvimento de um protótipo ciber-físico de um modelo de elevador monta-cargas. Este protótipo, denominado "MC3b", encontra-se presente no departamento de engenharia electrotécnica da Faculdade de Ciências e Tecnologias da Universidade Nova de Lisboa. No trabalho desenvolvido o maior foco foi a reestruturação do sistema de controlo, implementando novos controladores, código de programação e desenvolvendo meios de comando do variador de velocidade mais avançados. Foi também desenvolvido um simulador do protótipo e uma interface gráfica que permite controlar e monitorizar tanto o sistema simulado como o sistema físico, actuando como consola Homem-Máquina virtual. As principais contribuições foram o desenvolvimento do simulador, do sistema de controlo do projecto físico e do programa de controlo do modelo de elevador MC3b. A fim de demonstrar as capacidades dos controladores desenvolvidos, apresentam-se os resultados dos mesmos em ambientes simulado e físico. Todos os testes realizados no simulador revelaram um bom desempenho do mesmo, e do sistema de controlo. Os testes realizados no modelo físico revelaram desafios inesperados, devido ao erro presente em sensores, no entanto estes desafios foram cumpridos com a implementação de novo software. Os resultados deste modelo, embora não ideais, revelaram um bom desempenho geral dos sistemas de controlo desenvolvidos.In this dissertation the development of a Cyber-Physical system for a prototype freight lift model was proposed. The prototype lift, named "MC3b", is located at the department of electrical engineering of FCT-UNL. The biggest focus of the developed work was the restructuring of the control system of the elevator, implementing new controllers, programming code, and developing an alternative and more advanced method of command of the variable frequency drive. A simulator of the prototype was also developed, joined by a graphical user interface which can be used for controlling and monitoring both the real and virtual prototypes, acting as a virtual Human-Machine Interface. The main contributions were the development of the simulator, control system of the phisical prototype, and respective programing code. In order to show the performance of the developed work, the results of multiple tests made to both the simulator and physical prototype are presented. Every test done to the simulator reavealed favorable results to both the simulator and the control program. However, tests made to the real system revealed unexpected challenges. This challenges were overcomed and results, although not ideal, revealed a good overall performance of the developed control systems

The programmable logic controller : its prehistory, emergence and application

Programmable Logic Controllers (PLCs) are widely used devices controlling industrial machines and processes and many other diverse applications, requiring primarily, combinatorial logic and sequential control. The PLC is a hidden technology, little known by the general public and overlooked in academic historical studies of technology. The research reported in this thesis aims to address this lack of awareness. The thesis explores the development of sequential and combinatorial logic control technologies, the emergence of the PLC, its subsequent development and its industrial applications. Patents and first- hand accounts and experiences from senior industrial engineers in a number of diverse manufacturing industries have been used as the primary research sources since, as a hidden technology, academic historical accounts are sparse. This approach illustrates, through using the PLC as an example, a potential method of studying other, unrelated hidden technologies. The research has revealed the influence of geography, industrial settings and earlier engineering practices on the design, selection and application of PLC control technologies, and comments on the how these influences define specific communities of practice

Preventing Capability Abuse through Systematic Analysis of Exposed Interface

Connectivity and interoperability are becoming more and more critical in today’s software and cyber-physical systems. Different components of the system can better collaborate, enabling new innovation opportunities. However, to support connectivity and interoperability, systems and applications have to expose certain capabilities, which inevitably expands their attack surfaces and increases the risk of being abused. Due to the complexity of software systems and the heterogeneity of cyber-physical systems, it is challenging to secure their exposed interfaces and completely prevent abuses. To address the problems in a proactive manner, in this dissertation, we demonstrate that systematic studies of exposed interfaces and their usage in the real world, leveraging techniques such as program analysis, can reveal design-level, implementation-level, as well as configuration-level security issues, which can help with the development of defense solutions that effectively prevent capability abuse. This dissertation solves four problems in this space. First, we detect inconsistent security policy enforcement, a common implementation flaw. Focusing on the Android framework, we design and build a tool that compares permissions enforced on different code paths and identifies the paths enforcing weaker permissions. Second, we propose the Application Lifecycle Graph (ALG), a novel modeling approach to describing system-wide app lifecycle, to assist the detection of diehard behaviors that abuse lifecycle interfaces. We develop a lightweight runtime framework that utilizes ALG to realize fine-grained app lifecycle control. Third, we study real-world programmable logic controller programs for identifying insecure configurations that can be abused by adversaries to cause safety violations. Lastly, we conduct the first systematic security study on the usage of Unix domain sockets on Android, which reveals both implementation flaws and configuration weaknesses.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/149960/1/yurushao_1.pd

SFEDL’04 Preliminary Version Semantics and Analysis of Instruction List Programs Abstract

Instruction List (IL) is a simple typed assembly language commonly used in embedded control. There is little tool support for IL and, although defined in the IEC 61131-3 standard, there is no formal semantics. In this work we develop a formal operational semantics. Moreover, we present an abstract semantics, which allows approximative program simulation for a (possibly infinte) set of inputs in one simulation run. We also extended this framework to an abstract interpretation based analysis, which is implemented in our tool Homer. All these analyses can be carried out without knowledge of formal methods, which is typically not present in the IL community