[Retracted] SWOT: A Hybrid Hardware-Based Approach for Robust Fault-Tolerant Framework in a Smart Day Care

Table 2

Comparison with existing work on hardware-based approaches of fault detection [30–36].

Title	Summary	Observed gaps
Fault detection with limit checking [30]	The paper discusses fault detection methods using limit checking as follows	1. Fault detection is based only on limits calculated by different methods were discussed
	1. Limit checking of absolute values	2. Device aging/drift is not taken care of while calculating the threshold limits
	2. Using trend checking using the first derivative of readings	3. Timely current fluctuations/spikes are not considered
	3. A combination of absolute values and trends can be applied as limits	4. Missing data are not considered
	4. Detection with binary thresholds with an estimation of mean and variance
An automatic sensor fault detection and correction algorithm [31]	This article attempts to detect a faulty reading among a set of measurements and proposes a correction scheme. It involves two levels: the detection of a problem and its localization afterward	1. The outmoded approach of hardware redundancy for measurement is used. It involves extra cost, space, weight, and maintenance for redundant devices
		2. Detection of reliable and poor measurements relies on approximation or redundant data which may be temporarily affected
(12) United States patent (54) METHOD OF DETECTING FAULTS USING 373 A Sty [32]	An indicator for a faulted circuit was designed that reports a fault current reading for the monitored circuit crosses one of the levels of threshold limits even after some propagation delay	1. The indicator considered only the current levels of the device
		2. Other factors affecting the current consumption of the device were not considered like device aging, frequency of repairs, unplugging of the device
		3. IoT or smart devices/sensors are not considered
The study of hardware redundancy techniques to provide a fault-tolerant system. [33]	The paper studies different hardware redundancy techniques	The traditional approach for detecting faults. It involves extra cost, space, weight, and maintenance for redundant devices
An adaptive threshold algorithm for sensor fault based on the grey theory [34]	An adaptive dynamic threshold adjustment algorithm based on the grey theory. In this method, the threshold value can be dynamically adjusted according to the real-time mean and variance of the residual	Factors affecting the current consumption of the device were not considered like drift, spikes, frequency of repairs, unplugging of the device not considered
Hitchhiker’s guide to successful remote sensing deployments in Mongolia [35]	The author builds an economic air quality sensor that gathers real-time data from varied locations. The paper presents the implementation and challenges faced in the deployment of the same	Unplugged sensors were not anticipated and considered in their design
Fault detection using limit checking: a brief introductory review [36]	This includes fault detection using limit checking of absolute values, trend checking, fixed and adaptive thresholds, and change detection	Other factors affecting the current consumption of the device were not considered like device aging, frequency of repairs, and unplugging of the device