Resilience of an embedded architecture using hardware redundancy

In the last decade the dominance of the general computing systems market has being replaced by embedded systems with billions of units manufactured every year. Embedded systems appear in contexts where continuous operation is of utmost importance and failure can be profound. Nowadays, radiation poses a serious threat to the reliable operation of safety-critical systems. Fault avoidance techniques, such as radiation hardening, have been commonly used in space applications. However, these components are expensive, lag behind commercial components with regards to performance and do not provide 100% fault elimination. Without fault tolerant mechanisms, many of these faults can become errors at the application or system level, which in turn, can result in catastrophic failures. In this work we study the concepts of fault tolerance and dependability and extend these concepts providing our own definition of resilience. We analyse the physics of radiation-induced faults, the damage mechanisms of particles and the process that leads to computing failures. We provide extensive taxonomies of 1) existing fault tolerant techniques and of 2) the effects of radiation in state-of-the-art electronics, analysing and comparing their characteristics. We propose a detailed model of faults and provide a classification of the different types of faults at various levels. We introduce an algorithm of fault tolerance and define the system states and actions necessary to implement it. We introduce novel hardware and system software techniques that provide a more efficient combination of reliability, performance and power consumption than existing techniques. We propose a new element of the system called syndrome that is the core of a resilient architecture whose software and hardware can adapt to reliable and unreliable environments. We implement a software simulator and disassembler and introduce a testing framework in combination with ERA’s assembler and commercial hardware simulators

Rateless Codes for Near-Perfect Load Balancing in Distributed Matrix-Vector Multiplication

Large-scale machine learning and data mining applications require computer systems to perform massive matrix-vector and matrix-matrix multiplication operations that need to be parallelized across multiple nodes. The presence of straggling nodes -- computing nodes that unpredictably slowdown or fail -- is a major bottleneck in such distributed computations. Ideal load balancing strategies that dynamically allocate more tasks to faster nodes require knowledge or monitoring of node speeds as well as the ability to quickly move data. Recently proposed fixed-rate erasure coding strategies can handle unpredictable node slowdown, but they ignore partial work done by straggling nodes thus resulting in a lot of redundant computation. We propose a \emph{rateless fountain coding} strategy that achieves the best of both worlds -- we prove that its latency is asymptotically equal to ideal load balancing, and it performs asymptotically zero redundant computations. Our idea is to create linear combinations of the $m$ rows of the matrix and assign these encoded rows to different worker nodes. The original matrix-vector product can be decoded as soon as slightly more than $m$ row-vector products are collectively finished by the nodes. We conduct experiments in three computing environments: local parallel computing, Amazon EC2, and Amazon Lambda, which show that rateless coding gives as much as $3\times$ speed-up over uncoded schemes

Robust laser-free entanglement with trapped ions

Trapped ions with microwave radiation are a promising platform for universal quantum computing. However, a major obstacle in the way of scalability is the coupling of the qubits to their noisy environment. This thesis offers means to improve the fidelity of two-qubit entangling gates. To this end, we investigate noise from classical control hardware and study quantum control methods that increase the gate’s robustness. The noise spectrums of classical control hardware typically exhibit non-Markovian behaviour. Therefore, a transfer function in frequency space is derived for each source, transforming hardware noise to qubit-frame noise. It is found that voltage noise on the electrodes is a significant contribution to decoherence as it displaces the ions within the static magnetic field gradient. We propose and demonstrate a voltage noise cancellation scheme that is compatible with microfabricated surface traps. We then identify a library of quantum control methods that increase the robustness of a bichromatic interaction to both spin and motional decoherence. We also propose a novel σz ⊗ σz entangling gate which makes use of the intrinsic J-coupling interaction of ions in a static magnetic gradient. The resulting interaction is virtually insensitive to motional decoherence, which alleviates stringent experimental requirements. We finally demonstrate a bichromatic interaction that is simultaneously robust to spin and motional decoherence, by means of continuous dynamical decoupling and phase modulation on the sidebands. Recalling that noise in the ion’s position couples into magnetic field noise due to the static magnetic field gradient, we use this noise mechanism as the basis of a promising electric field sensor. We experimentally demonstrate AC electrometry with a sensitivity of S = 7.0(5)mVm−1Hz−1/2. Noise spectroscopy was also demonstrated and was limited by the noise floor, where the minimum sensitivity was 545 nVm−1Hz−1/2.Open Acces

Design Space Exploration and Resource Management of Multi/Many-Core Systems

The increasing demand of processing a higher number of applications and related data on computing platforms has resulted in reliance on multi-/many-core chips as they facilitate parallel processing. However, there is a desire for these platforms to be energy-efficient and reliable, and they need to perform secure computations for the interest of the whole community. This book provides perspectives on the aforementioned aspects from leading researchers in terms of state-of-the-art contributions and upcoming trends

Competencies needed to prepare intermediate life support (ils) paramedics in Gauteng to manage traumatic stress in the work environment

This qualitative study explored the effects of trauma as well as coping mechanisms used to deal with post-traumatic stress experienced by ILS paramedics providing emergency care services in the Gauteng Province, South Africa. It also looked at the competencies needed to cope with traumatic stress and promote biopsychosocial well-being. It is argued that it is important to look at this subject from a South African perspective since most of the published research on the sources and effects of trauma on paramedics and other frontline emergency services personnel experience comes from developed countries. It was discovered that there is minimal empirical research from South Africa on similar topics, except for a study in the Cape Town metropole. In addition to that, most published research relied on quantitative data collection methods. Through qualitative case study research this thesis draws on observations and relevant data gathered by way of semi-structured face to face interviews with eleven operational Intermediate Life Support (ILS) paramedics who work in the Gauteng province. Data is gathered on the sources of stress and coping mechanisms currently used by the paramedics. The gathered data was analysed using thematic analysis. The results show that the sources of stress for paramedics include attending gruesome scenes, extreme pressure to save lives and attending a scene where a child or a colleague is involved. It was also observed that the paramedics have a set of coping strategies to manage post-traumatic stress which are both positive and negative coping strategies. In addition to interviews with ILS paramedics from whom data is gathered on their education and training, the results in this thesis gathered insight from a panel of six experts who were engaged through a focus group discussion. These experts have demonstrable expertise in curriculum development, trauma counselling and training. The panel recommended that the training of the paramedics must be more realistic such that the paramedics are better equipped to deal with the challenges they may encounter in the work environment. It was also revealed that those who train paramedics are not well equipped to deliver the health and wellness module. It can be concluded that some paramedics are not well equipped to deal with traumatic events they encounter in the field. The researcher recommends that the health and wellness module be delivered by people who are specifically trained to deal with mental health issues. Insights gathered in this study will help the paramedics, those they help and their families

Radiation Tolerant Electronics, Volume II

Research on radiation tolerant electronics has increased rapidly over the last few years, resulting in many interesting approaches to model radiation effects and design radiation hardened integrated circuits and embedded systems. This research is strongly driven by the growing need for radiation hardened electronics for space applications, high-energy physics experiments such as those on the large hadron collider at CERN, and many terrestrial nuclear applications, including nuclear energy and safety management. With the progressive scaling of integrated circuit technologies and the growing complexity of electronic systems, their ionizing radiation susceptibility has raised many exciting challenges, which are expected to drive research in the coming decade.After the success of the first Special Issue on Radiation Tolerant Electronics, the current Special Issue features thirteen articles highlighting recent breakthroughs in radiation tolerant integrated circuit design, fault tolerance in FPGAs, radiation effects in semiconductor materials and advanced IC technologies and modelling of radiation effects

Process alarm management - An investment towards safe and reliable operations

Master's thesis in Technology and Operations ManagementMost of the commercial buildings and private homes are configured with a certain number of alarms to deal with emergency situations, such as fire alarms, HVAC fail alarms, theft alarms, water leakage alarms etc. However, for an industrial process plant, all alarms and their configuration parameters collectively feed into a big database. For a typical offshore installation, the alarm database for the integrated control and safety system may consist of 40000 to 150000 alarms which must be monitored. Considering the vastness of an alarm database for a process installation, and the risk of missing critical alarms, there is a need for a regulated and a guided system to handle and integrate all aspects of alarm engineering to create a functional alarm system. Such an alarm system must: • Be built on “principles of alarm design” for process industries • Be complaint with applicable regulations • Be usable by process operators in management of abnormal situations • Perform in line with organisational performance measures As process industries are getting increasingly complex, with new technologies and expansion projects, process operators are becoming overloaded with new systems and new alarms dominate the unnecessary disturbance. Alarm systems need to be well specified and maintained to ensure safe operations. During the period between August 2000 and September 2002, NPD (Norwegian Petroleum Directorate) has carried out the supervision of alarm systems on seven production facilities within the Norwegian Continental Shelf. Authorised mapping of alarm systems revealed essentially the same weaknesses and same problem areas, independent of system vendor, operating company, type of facility and age of device. Despite the limited mapping that has been made, NPD find it reasonable to assume that, the results from these activities are somewhat representative of the challenges of other facilities on the Norwegian continental shelf. This thesis will choose to provide a proactive approach to draft various procedures for a functional alarm system with all the specifics mentioned above for an alarm system within the frame work of regulations limited to Norwegian continental shelf. A well-functioned alarm system combines with coordinated operations management can drive not only safety and ensure regulatory compliance but promote better plant availability and throughput, delivering real business value. (Honeywell, 2017