| 1. |
- Devaraj, Lokesh, et al.
(författare)
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Improvements proposed to noisy-OR derivatives for multi-causal analysis: A case study of simultaneous electromagnetic disturbances
- 2024
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Ingår i: International Journal of Approximate Reasoning. - 0888-613X .- 1873-4731. ; 164
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Tidskriftsartikel (refereegranskat)abstract
- In multi-causal analysis, the independence of causal influence (ICI) assumed by the noisy-OR (NOR) model can be used to predict the probability of the effect when several causes are present simultaneously, and to identify (when it fails) inter-causal dependence (ICD) between them. The latter is possible only if the probability of observing the multi-causal effect is available for comparison with a corresponding NOR estimate. Using electromagnetic interference in an integrated circuit as a case study, the data corresponding to the probabilities of observing failures (effect) due to the injection of individual (single cause) and simultaneous electromagnetic disturbances having different frequencies (multiple causes) were collected. This data is initially used to evaluate the NOR model and its existing derivatives, which have been proposed to reduce the error in predictions for higher-order multi-causal interactions that make use of the available information on lower-order interactions. Then, to address the identified limitations of the NOR and its existing derivatives, a new deterministic model called Super-NOR is proposed, which is based on correction factors estimated from the available ICD information.
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| 2. |
- Khan, Qazi Mashaal, 1992, et al.
(författare)
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Validation of IC Conducted Emission and Immunity Models Including Aging and Thermal Stress
- 2023
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Ingår i: IEEE Transactions on Electromagnetic Compatibility. - 0018-9375 .- 1558-187X. ; 65:3, s. 780-793
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Tidskriftsartikel (refereegranskat)abstract
- Environmental factors, such as aging and thermal stress, can seriously impact the electromagnetic compatibility behavior of an integrated circuit (IC). The standardized IC emission model for conducted emission (ICEM-CE) and IC immunity model for conducted immunity (ICIM-CI) can be used in industry to predict electromagnetic behavior at the IC and the printed circuit board level. However, these do not take into account the effect of aging and extreme temperature variations. In this article, a custom IC designed in silicon-on-insulator technology, containing several independent analog blocks, is used to characterize the influence of aging and temperature on conducted emission and immunity through measurements and transistor-level simulations. The highly accelerated temperature and humidity stress test (HAST) was performed to evaluate aging and its influence on IC parameters. The results show that the passive distribution network is only influenced by thermal stress and not HAST aging. The latter mainly affects the active elements in the IC and reduces the conducted emission and immunity levels through intrinsic permanent degradation mechanisms. Furthermore, thermal stress mainly causes drifts in the transistor characteristics (such as threshold voltage and effective mobility), which affect the conducted emission and immunity levels and resulting in soft failures. All drifts/tolerances collected from measurements and simulations are characterized in a way that makes it possible to include them in potential future versions of the ICEM-CE and ICIM-CI standards.
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| 3. |
- Koohestani, M., et al.
(författare)
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Frequency Selective Surfaces for Electromagnetic Shielding of Pocket-Sized Transceivers
- 2020
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Ingår i: IEEE Transactions on Electromagnetic Compatibility. - 0018-9375 .- 1558-187X. ; 62:6, s. 2785-2792
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a comprehensive study of the use of small-sized frequency selective surfaces (FSS) to selectively shield pocket-sized devices against EM disturbances. A typical use case is to protect a 2.4-GHz transceiver (e.g. WiFi/Bluetooth) against ISM/GSM disturbances (around 868/915 MHz), using an 8.2 – 4.1 cm FSS structure. A detailed comparison is drawn between results in real and emulated far-fields for different FSS-to-antenna distances (5 and 25 mm), which is further confirmed by emission measurements employing an open transverse electromagnetic cell. Results demonstrate, in line with full-wave simulations including calculated Poynting integrals, that such a FSS can effectively reduce power by about 5 dB in the stopband, while providing no attenuation in the passband and is small enough for an easy integration. Moreover, it is shown that the farther the FSS from the antenna, the closer the results to a no-FSS scenario. This provides an insight to reconsider FSSs for the shielding of mobile and/or smart devices.
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