Mohammad Samie

Prokaryotic Bio-Inspired Model for Embryonics

This paper is presented in conjunction with, and forms the first part of, the paper entitled “Prokaryotic Bio-Inspired Systems.” In this part we propose and investigate a novel prokaryotic cell-based bio-inspired model suitable to implement self-healing bio-inspired systems. A key feature of our model is that system reliability can be increased with a minimal amount of hardware overhead. It also offers a bio-inspired compression/decompression technique that exploits the intimate relationship between different genes. Distributed DNA, highly dynamic and flexible routing resources and optimized self-repair characteristics (using Block and cell elimination) are some of the other advantages of the proposed model.

Computationally Efficient, Real-Time, and Embeddable Prognostic Techniques for Power Electronics

Power electronics are increasingly important in new generation vehicles as critical safety mechanical subsystems are being replaced with more electronic components. Hence, it is vital that the health of these power electronic components is monitored for safety and reliability on a platform. The aim of this paper is to develop a prognostic approach for predicting the remaining useful life of power electronic components. The developed algorithms must also be embeddable and computationally efficient to support on-board real-time decision making. Current state-of-the-art prognostic algorithms, notably those based on Markov models, are computationally intensive and not applicable to real-time embedded applications. In this paper, an isolated-gate bipolar transistor (IGBT) is used as a case study for prognostic development. The proposed approach is developed by analyzing failure mechanisms and statistics of IGBT degradation data obtained from an accelerated aging experiment. The approach explores various probability distributions for modeling discrete degradation profiles of the IGBT component. This allows the stochastic degradation model to be efficiently simulated, in this particular example ~1000 times more efficiently than Markov approaches.

Prokaryotic Bio-Inspired System

This paper presents a novel bio-inspired artificial system that is based on biological prokaryotic organisms and their artificial model, and proposes a new type of fault tolerant, self-healing architecture. The system comprises of a sea of bio-inspired cells, arranged in a rectangular array with a topology that is similar to that employed by FPGAs. A key feature of the array is its high level of fault tolerance, achieved with only minimal amount of hardware overhead. Inspired by similar biological processes, the technique is based on direct-correlated redundancy, where the redundant (stand-by) configuration bits, as extrinsic experience, are shared between blocks and cells of a colony in the artificial system. Bio-inspired array implementation is particularly advantageous in applications where the system is subject to extreme environmental conditions such as temperature, radiation, SEU (Single Event Upset) etc. and where fault tolerance is of particular importance.

Bio-inspired self-test for evolvable fault tolerant hardware systems

This paper presents a novel bio-inspired self-test technique for the implementation of evolvable fault tolerant systems based on the structure, behavior and processes observed in prokaryote unicellular organisms. Such Unitronic (unicellular electronic) artificial systems are implemented by FPGA-like bio-inspired cellular arrays and made up of structurally identical cells. All cells possess self-diagnostic and self-healing capability. Our underlying conceptual postulation is: if it can be guaranteed that during the test phase a cell, the internal functionality of which is configured with a complementary input sequence, demonstrates the same functionality, as that with the original sequence during its normal mode of operation, then the cell is fault free, otherwise it is faulty. Our proposed self-test can evaluate all stuck-at-zero and stuck-at-one faults of the system if at any time only one fault exists. Hardware redundancy is optimised because the same hardware, by simple reconfiguration is able to test itself and thus eliminates the need of duplicated, triplicated hardware.

UNITRONICS: A novel bio-inspired fault tolerant cellular system

We cannot yet match the high degree of reliability that biological systems possess when building electronic systems, no matter how intelligent they are. While proposals to date to solve this problem have demonstrated the feasibility of the bio-inspired approach, the resulting systems were often unduly complex. This paper presents a radically new approach to building fault tolerant systems. It proposes a novel model that uses the characteristics and behaviour of unicellular organisms, such as those of bacteria and bacterial communities, to construct highly reliable electronic systems with online fault repair properties. It demonstrates the feasibility of using bio-inspired cellular arrays with built-in self-diagnostic and self-repair capability to construct complex electronic systems.

SABRE: a bio-inspired fault-tolerant electronic architecture

As electronic devices become increasingly complex, ensuring their reliable, fault-free operation is becoming correspondingly more challenging. It can be observed that, in spite of their complexity, biological systems are highly reliable and fault tolerant. Hence, we are motivated to take inspiration for biological systems in the design of electronic ones. In SABRE (self-healing cellular architectures for biologically inspired highly reliable electronic systems), we have designed a bio-inspired fault-tolerant hierarchical architecture for this purpose. As in biology, the foundation for the whole system is cellular in nature, with each cell able to detect faults in its operation and trigger intra-cellular or extra-cellular repair as required. At the next level in the hierarchy, arrays of cells are configured and controlled as function units in a transport triggered architecture (TTA), which is able to perform partial-dynamic reconfiguration to rectify problems that cannot be solved at the cellular level. Each TTA is, in turn, part of a larger multi-processor system which employs coarser grain reconfiguration to tolerate faults that cause a processor to fail. In this paper, we describe the details of operation of each layer of the SABRE hierarchy, and how these layers interact to provide a high systemic level of fault tolerance.

Developing Prognostic Models Using Duality Principles for DC-to-DC Converters

Within the field of Integrated System Health Management, there is still a lack of technological approaches suitable for the creation of adequate prognostic model for large applications whereby a number of similar or even identical subsystems and components are used. Existing similarity among a number of different systems, which are comprised of similar components but with different topologies, can be employed to assign the prognostics of one system to other systems using an inference engine. In the process of developing prognostics, this approach will thereby save resources and time. This paper presents a radically novel approach for building prognostic models based on system similarity in cases where duality principle in electrical systems is utilized. In this regard, unified damage model is created based on standard Tee/Pi models, prognostics model based on transfer functions, and remaining useful life (RUL) estimator based on how energy relaxation time of system is changed due to degradation. An advantage is that the prognostic model can be generalized such that a new system could be developed on the basis and principles of the prognostic model of other systems. Simple electronic circuits, dc-to-dc converters, are to be used as an experiment to exemplify the potential success of the proposed technique validated with prognostics models from particle filter.

Novel Bio-Inspired Approach for Fault-Tolerant VLSI Systems

Living organisms are complex systems, and yet they possess extremely high degrees of reliability. Since failures are local, their repair will often be taken on the local (cell) level. Engineers have long sought systems that could offer similar reliability and have relatively recently started trying to integrate ideas inspired by nature into the modern silicon technology of today. While bio-inspired proposals inspired by multicellular systems demonstrated feasibility, the resulting systems were often unduly complex. We are proposing a radically new methodology inspired by the characteristics, morphology, and behavior of simpler prokaryotic bacteria and bacterial communities. The hypothesis we use is that such simple unicellular organisms could help to build simpler cost effective systems, but with improved reliability than hitherto achieved by other methods. The result is a cellular array-based fault-tolerant electronic system with online self-test and self-repair capability. These ideas are simulated, tested, and verified through the successful construction of demonstrators: a proportional, integral, and differential and a robot controller. This paper discusses the underlying biological principles that guide our research and the bio-inspired model that we have derived. It also gives a detailed circuit and system description of the architecture and its run-time self-diagnostic and self-repair capability.

A Novel Intermittent Fault Detection Algorithm and Health Monitoring for Electronic Interconnections

There are various occurrences and root causes that result in no-fault-found (NFF) events but an intermittent fault (IF) is the most frustrating. This paper describes the challenging and most important area of an IF detection and health monitoring that focuses toward NFF situation in electronics interconnections. The experimental work focuses on mechanically-induced intermittent conditions in connectors. This paper illustrates a test regime, which can be used to repeatedly reproduce intermittence in electronic connectors, while subjected to vibration. A novel algorithm is used to detect an IF in interconnection. It sends a sine wave and decodes the received signal for intermittent information from the channel. This algorithm has been simulated to capture an IF signature using PSpice (electronic circuit simulation software). A simulated circuit is implemented for practical verification. However, measurements are presented using an oscilloscope. The results of this experiment provide an insight into the limitations of existing test equipment and requirements for future IF detection techniques. Aside from scheduled maintenance, this paper considers the possibility for in-service intermittent detection to be built into future systems, i.e., can IFs be captured without external test gear?

Novel bio-inspired self-repair algorithm for evolvable fault tolerant hardware systems

This paper investigates and presents a novel self-repair algorithm, based on a prokaryotic bio-inspired artificial model, for implementing evolvable self-healing bio-inspired systems. The key feature of the model is that system reliability can be increased with only a minimal amount of hardware overhead. It also offers a bio-inspired compression/decompression technique that exploits the intimate relationship between different genes. Distributed DNA, highly dynamic and optimized genome redundancy and optimized self-repair characteristics (using block and cell elimination) are some of the other advantages of the proposed model.