An embryonic approach to reliable digital instrumentation based on evolvable hardware

Embryonics encompasses the capability of self-repair and self-replication in systems. This paper presents a technique based on reconfigurable hardware coupled with a novel backpropagation algorithm for reconfiguration, together referred to as evolvable hardware (EHW), for ensuring reliability in digital instrumentation. The backpropagation evolution is much faster than genetic learning techniques. It uses the dynamic restructuring capabilities of EHW to detect faults in digital systems and reconfigures the hardware to repair or adapt to the error in real-time. An example application is presented of a robust BCD to a seven-segment decoder driving a digital display. The results obtained are quite interesting and promise quick and low cost embryonic schemes for reliability in digital instrumentation.     

Chemical sensing systems using xerogel-based sensor elements and CMOS photodetectors

We present the first example of an integrated complementary metal-oxide-semiconductor (CMOS) photodetector coupled with a solid-state xerogel-based thin-film sensor to produce a compact chemical sensor system. We compare results using two different CMOS-based detector systems to results obtained by using a standard photomultiplier tube (PMT) or charge-coupled device (CCD) detector. Because the chemical sensor elements are governed by a Stern-Volmer relationship, the Stern-Volmer quenching constant is used as the primary comparator between the different detectors. All of the systems yielded Stern-Volmer constants from 0.042 to 0.049 O/sub 2/%/sup -1/. The results show that the CMOS detector system yields analytical data that are comparable to the CCD- and PMT-based systems. The disparity between the data obtained from each detector is primarily associated with the difference in how the signals are obtained by each detector as they presently exist. We have also observed satisfactory reversibility in the operation of the sensor system. The CMOS-based system exhibits a response time that is faster than the chemical sensor element's intrinsic response time, making the CMOS suitable for time-dependent measurements. The CMOS array detector also uses less than 0.1% the power in comparison to a standard PMT or CCD. The combined xerogel/CMOS system represents an important step toward the development of a portable, efficient sensor system.     

Data base management systems: The influence of hardware

The technology of software of data base management systems is described, and the influence that hardware has had on such systems in the past is discussed. In addition, an attempt is made to highlight some hardware advances that are awaited eagerly by software designers.     

Application of control and measuring hardware in automatic scientific-research systems

Translated from Izmeritel'naya Tekhnika, No. 5, pp. 13–14, May, 1988.     

Phase-diversity wave-front sensor for imaging systems

A phase-diversity wave-front sensor has been developed and tested at the Lockheed Palo Alto Research Labs (LPARL). The sensor consists of two CCD-array focal planes that record the best-focus image of an adaptive imaging system and an image that is defocused. This information is used to generate an object-independent function that is the input to a LPARL-developed neural network algorithm known as the General Regression Neural Network (GRNN). The GRNN algorithm calculates the wave-front errors that are present in the adaptive optics system. A control algorithm uses the calculated values to correct the errors in the optical system. Simulation studies and closed-loop experimental results are presented.     

汽车车内噪声主动控制系统扬声器与麦克风布放优化方法

利用声固耦合边界元仿真方法与多目标遗传算法,实现了面向对象的车内噪声主动控制(ANC)系统扬声器麦克风布放方案的优化。首先基于自适应算法,推导了车内噪声主动控制系统降噪性能预测方法,并利用声固耦合边界元仿真方法,实现了面向对象的ANC系统降噪性能预测;在该仿真模型的基础上,建立对应的代理模型,以实现对系统降噪性能的快速预测;最后利用多目标遗传算法,获得系统关于扬声器麦克风数量与多个频率下降噪量的Pareto最优解集。该最优解集能定量描述ANC系统扬声器麦克风数量与降噪性能之间的关系,并为该系统与车辆的匹配提供依据。     

RIFIT: analyzing hardware and software in safeguarding systems

Currently many systems used to safeguard processes in industry use a combination of hardware and software. Many of the analysis techniques applied in this field, however, quantify aspects of hardware only. This paper presents a technique that is used to quantify the safety of safeguarding systems as a whole, including hardware and software. The techniques used bases itself on a combination of simulation and fault injection techniques. This paper will present this new technique and will demonstrate that it is possible using this “Random Intelligent Failure Injection Technique” to analyze and optimize practical safeguarding systems.     

Detecting test set hardware degradation using statistical data modelling

In electronic device manufacturing, a significant amount of time is spent testing the product using sophisticated test sets. These test sets routinely develop hardware problems that cause disruption of the manufacturing process. This paper discusses how computerized networking of test sets can be used to systematically monitor and detect these hardware problems. A statistical methodology for modelling and analysing test set data is presented, along with a detailed specific example.     

Frequency-readout temperature sensor using microcircuitry

A resonant piezoelectric temperature sensor with frequency readout is described for thermophysical measurements in the temperature range 4.2–430 K; the device is insensitive to strong (up to 7 T) magnetic fields.Translated from Izmeritel'naya Tekhnika, No. 7, pp. 60–61, July, 1993.     

Motion-sensitive position sensor using bacteriorhodopsin

A concept of motion-sensitive position sensing that uses a film of bacteriorhodopsin (bR) treated with a high-pH buffer is proposed. The polarity of photo-emf, which depends on the excited intermediates of the bR molecule, can be used to determine movement direction. The M intermediate state with a long lifetime can be used to record the initial position. The bR-based position sensor can sense two positions of a moving object at two different times.     

Current sensor using heterodyne detection

Based on the Faraday effect for measuring ac current, we describe a fiber-optic sensor that uses laser-diode intensity modulation to perform heterodyne signal detection. The sensor output at the carrier frequency is used as a reference signal to normalize the results. The sensing element consists of a few coils low-birefringence fibers between polarizers. We built the current sensor described above and tested its performance-sensitivity and noise-as functions of the angle between polarizers.     

Developments in hardware and software for computer controlled servohydraulic fatigue testing systems

During the last ten years digital computers have become increasingly important in the field of fatigue testing, not only replacing conventional single function electronic devices but also offering new possibilities in items of the organization and performance of materials testing equipment. This paper outlines typical ranges of applications for computers; the development of special hardware and software for use with servohydraulic fatigue test machines; and general trends regarding the use of computers in fatigue testing laboratories.     

Managing obsolescence of embedded hardware and software in secure and trusted systems

Obsolescence of integrated systems which contain hardware and software is a problem that affects multiple industries and can occur for many reasons, including technological, economic, organizational, and social factors. It is especially acute in products and systems that have long life cycles, where a high rate of technological innovation of the subcomponents result in a mismatch in life cycles between the components and the systems. While several approaches for obsolescence forecasting exist, they often require data that may not be available. This paper describes an approach using non-probabilistic scenarios coupled with decision analysis to investigate how particular scenarios influence priority setting for products and systems. Scenarios are generated from a list of emergent and future conditions related to obsolescence. The key result is an identification of the most and least disruptive scenarios to the decision maker’s priorities. An example is presented related to the selection of technologies for energy islanding, which demonstrates the methodology using six obsolescence scenarios. The paper should be of broad interest to scholars and practitioners engaged with enterprise risk management and similar challenges of large-scale systems.     

Fault-tolerant homopolar magnetic bearings

This paper summarizes the development of a novel magnetic suspension that improves reliability via fault-tolerant operation. The suspension is suitable for flywheels used in satellites and space stations for attitude control and energy storage. Specifically, we show that flux coupling between poles of a homopolar magnetic bearing can deliver desired forces even after termination of coil currents to a subset of "failed poles". Linear, coordinate-decoupled force-voltage relations are also maintained before and after failure by bias linearization. We determined current distribution matrices that adjust the currents and fluxes following a pole set failure for many faulted pole combinations. We used one-dimensional magnetic circuit models with fringe and leakage factors derived from detailed, three-dimensional finite-element field models to obtain the current distribution matrices and the system response. Reliability is based on the success criterion that catcher bearing-shaft contact does not occur after pole failures. The magnetic bearing reliability is improved by increasing the number of the radial poles. An advantage of our method over other redundant approaches is a significantly reduced requirement for backup hardware such as additional actuators or power amplifiers.     

Nanoparticle metal-oxide films for micro-hotplate-based gas sensor systems

We report on the use of either reactive magnetron sputtering or screen printing to deposit tin and tungsten-oxide gas-sensitive layers onto integrated micromachined arrays. The procedures allow the deposition of the sensing layers before membranes have been etched, which leads to gas microsensors with an excellent fabrication yield. The microstructure of the sensitive films is analyzed by means of SEM and EDX. The response of the different microarrays to ethanol, acetone, and ammonia vapors and their binary mixtures, and toxic gases such as NO/sub 2/ and CO, is studied at different operating temperatures. The response of the different sensors to ambient humidity is also investigated. Finally, it is shown that by using PCA and fuzzy ARTMAP neural networks, it is possible to simultaneously identify and quantify the toxic gases with a 100% success rate. A 95% success rate is obtained in the semi-quantitative analysis of vapors and vapor mixtures. These results prove the viability and usefulness of the techniques introduced to obtain integrated sensor microarrays that are suitable for battery-powered gas/vapor monitors.     

Instrumentation architecture and sensor fusion for systems control

This paper presents a systematic approach for the design of an instrumentation architecture and a sensor data fusion concept which together enable the robust control of complex electromechanical systems. The development is based on the theory of hyperstability. Earlier results are generalized and previous restrictions on sensors are relaxed to broaden the applicability of the proposed method. Experimental results validate the methodology and confirm its efficacy in practical applications     

Location information-aided task-oriented self-organization of ad-hoc sensor systems

A novel task-oriented self-organization algorithm that accounts for mostly location-dependent tasks and heterogeneous sensors inherent in dense ad-hoc sensor systems is proposed. It forms a sensor group for an announced task by sequentially selecting the best matched sensors using a leader election algorithm and a residual task calculation algorithm. To improve the associated communication overhead, the sensor node location information is used in task broadcasting, thus confining the algorithm implementation to a dynamically maintained contributor group which comprises of those sensors which may contribute to the task. Sensor localization is based on a refinement of an algorithm in which utilizes only the neighborhood information of each sensor node corresponding to its each preset radio transmission power level. The proposed self-organization algorithm and how various system parameters affect its performance are examined via extensive simulations. In a densely deployed sensor system, when the refined localization scheme is demonstrated to achieve very good localization, the proposed self-organization algorithm consistently yields a sensor group that covers the announced task.