The rapid spread of the novel coronavirus disease, COVID-19, and its resulting situation has garnered much effort to contain the virus through scientific research. The tragedy has not yet fully run its course, but it is already clear that the crisis is thoroughly global, and science is at the forefront in the fight against the virus. This includes medical professionals trying to cure the sick at risk to their own health; public health management tracking the virus and guardedly calling on such measures as social distancing to curb its spread; and researchers now engaged in the development of diagnostics, monitoring methods, treatments and vaccines. Recent advances in non-contact sensing to improve health care is the motivation of this study in order to contribute to the containment of the COVID-19 outbreak. The objective of this study is to articulate an innovative solution for early diagnosis of COVID-19 symptoms such as abnormal breathing rate, coughing and other vital health problems. To obtain an effective and feasible solution from existing platforms, this study identifies the existing methods used for human activity and health monitoring in a non-contact manner. This systematic review presents the data collection technology, data preprocessing, data preparation, features extraction, classification algorithms and performance achieved by the various non-contact sensing platforms. This study proposes a non-contact sensing platform for the early diagnosis of COVID-19 symptoms and monitoring of the human activities and health during the isolation or quarantine period. Finally, we highlight challenges in developing non-contact sensing platforms to effectively control the COVID-19 situation.

In this paper, with the reformulation of short-open-load-reciprocal (SOLR), the influence of non-ideal standards on S-parameter uncertainties is investigated by two different methods. The SOLR calibration algorithm is reformulated by our recently proposed theory, which helps to simplify the mathematical derivation. Then, based on the uncalibration model, the one-step and two-step methods are developed for the sensitivity analysis of SOLR. These two methods come from different theories that were originally developed for SOLT and TRL, respectively. Finally, the analytical expressions of the sensitivity coefficients are derived, and the results obtained from these two methods are proved to be just opposite in sign.

The technique of laser cooling of atoms gives an opportunity to improve the performance of atomic clocks by using laser-cooled atoms. The most successful cold atom clock, called the atomic fountain, is now widely used as the primary frequency standard in many labs. The cold atom clock for satellite applications, however, has not been reported so far due to special requirements of space applications. Here, we report the development of an engineering model of a satellite-borne cold atom clock, which satisfied all requirements of in-orbit operation. The core of the clock’s principle is the laser cooling of atoms by diffuse laser lights inside the microwave cavity. The structure of the physics package is presented, and its main parameters are also given. The principle and design of the optical bench are described. The initial test results are presented, and the possible improvements are also discussed.

This We present a highly stable and miniaturised optical system designed for a caesium satellite-borne cold atom clock (CSCAC). The optical system was integrated on a $224{\mathop{\rm mm}\nolimits} {\rm{ }} \times {\rm{ }}195{\mathop{\rm mm}\nolimits} {\rm{ }} \times {\rm{ }}112{\mathop{\rm mm}\nolimits} $ aluminium-based silicon carbide bench and emitted laser beams with four different frequencies on three fiber ports to capture, cool, prepare, and detect atoms. The optical system, utilizing a compact three-layer optical-mechanical and thermal management design, passed environmental simulation tests and adapted to a special satellite-borne environment. The optical system stability meets the laser requirements of the clock.