An Underwater Source Localization Method Using Bearing Measurements.

Angle-of-arrival (AOA) measurements are often used in underwater acoustical localization. Different from the traditional AOA model based on azimuth and elevation measurements, the AOA model studied in this paper uses bearing measurements. It is also often used in the Ultra-Short Baseline system (USBL). However, traditional acoustical localization needs additional range information. If the range information is unavailable, the closed-form solution is difficult to obtain only with bearing measurements. Thus, a localization closed-form solution using only bearing measurements is explored in this article. A pseudo-linear measurement model between the source position and the bearing measurements is derived, and considering the nonlinear relationship of the parameters, a weighted least-squares optimization equation based on multiple constraints is established. Different from the traditional two-step least-squares method, the semidefinite programming (SDP) method is designed to obtain the initial solution, and then a bias compensation method is proposed to further minimize localization errors based on the SDP result. Numerical simulations show that the performance of the proposed method can achieve Cramer-Rao lower bound (CRLB) accuracy. The field test also proves that the proposed method can locate the source position without range measurements and obtain the highest positioning accuracy.

A Robust INS/USBL/DVL Integrated Navigation Algorithm Using Graph Optimization.

The Autonomous Underwater Vehicle (AUV) is usually equipped with multiple sensors, such as an inertial navigation system (INS), ultra-short baseline system (USBL), and Doppler velocity log (DVL), to achieve autonomous navigation. Multi-source information fusion is the key to realizing high-precision underwater navigation and positioning. To solve the problem, a fusion scheme based on factor graph optimization (FGO) is proposed. Due to multiple iterations and joint optimization of historical data, FGO could usually show a better performance than the traditional Kalman filter. In addition, considering that USBL and DVL are usually heavily influenced by the environment, outliers are often present. A robust integrated navigation algorithm based on a maximum correntropy criterion and FGO scheme is proposed. The proposed algorithm solves the problem of multi-sensor fusion and non-Gaussian noise. Numerical simulations and field tests demonstrate that the proposed FGO scheme shows a better performance and robustness than the traditional Kalman filter. Compared with the traditional Kalman filtering, the positioning accuracy is improved by 5.3%, 9.1%, and 5.1% in the east, north, and height directions. It can realize a more accurate navigation and positioning of underwater multi-sensors.

Environmental and Health Impacts of Crop Residue Burning: Scope of Sustainable Crop Residue Management Practices.

The burning of crop residue in the open field has become a significant concern for climate change mitigation efforts worldwide. This practice has led to air quality impairment, smog, haze, heat waves, and different health problems. These could be avoided by adopting sustainable crop residue management practices (SCRMPs) and enabling farmers to engage in SCRMPs. Assessing the health effects at the household level is critical for understanding this problem and finding a solution. Using the primary dataset of 420 farmers from Punjab, Pakistan, we estimated the incurred impacts and costs of crop residue burning. We calculated the health and environmental benefits associated with adopting SCRMPs by comparing the two groups of farmers (adopters and non-adopters). Furthermore, we used a propensity score matching technique to measure the causal impact of SCRMPs adoption on health costs. The findings showed that a surprisingly large number of farmers are all aware of the adverse effects of residue burning, and many do not burn crop residues and instead use SCRMPs. This study found that households with chronic and non-chronic diseases become acute, and the severity increases during the burning period. They spend USD 13.37 to USD 8.79 on chronic and non-chronic diseases during the burning season, respectively. Consequently, the use of SCRMPs has a positive effect on healthcare costs. Our study findings highlight the meaningful implications for developing a new policy to promote the sustainable utilization of crop residues and enhance their adoption in Pakistan.

[Responses of radial growth of Quercus mongolica to stand density and climatic factors in a mountainous area of eastern Liaoning Province, China]. / è¾½ä¸œå±±åŒºè’™å¤æ Žå¾„å‘ç”Ÿé•¿å¯¹æž—åˆ†å¯†åº¦å’Œæ°”å€™å› å­çš„å“åº”.

To explore the effects of stand density and climatic factors on radial growth of Quercus mongolica, we used tree ring chronology to examine the radial growth changes in a secondary Q. mongolica forest under different levels of stand density (thinning). The meteorological data combined with the driving factors of Q. mongolica growth were analyzed. The results showed that the radial growth of Q. mongolica was significantly affected by stand density. The mean annual radial growth of Q. mongolica was 3.12 mm in low-density virgin forest, 1.55 and 1.42 mm in the two medium-density secondary forests, respectively, and 0.96 mm in high-density secondary forest. The thinning intensity of 20% had a limited effect on promoting the radial growth recovery of high-density forest (1900 trees·hm-2), but had a significant effect on medium-density forest (1600 trees·hm-2). The radial growth of Q. mongolica was sensitive to the precipitation changes in January and February of the current year. Thinning reduced the sensitivity of Q. mongolica radial growth to climate. Under scenarios of climate warming and drying, density regulation could be beneficial in mitigating the adverse effects of climate change on the growth of Q. mongolica.

Exploring Factors Influencing Farmers' Continuance Intention to Crop Residue Retention: Evidence from Rural China.

Over the past decade, crop residue burning after harvest is prevalent in developing countries. Promoting crop residue retention to replace residue burning is effective in improving air quality and contributing to the mitigation of global climate change. This study examines farmers' continuance intention of crop residue retention, using the expectation confirmation model (ECM) and survey data from 542 rice farmers in Hubei Province, P.R. The results show that farmers' perceived usefulness, confirmation, perceived ease of use, and satisfaction significantly have direct or indirect positive impacts on their continuance intention on adopting crop residue retention. In particular, perceived ease of use contributes the most. Perceived usefulness and perceived ease of use act as intermediaries in the relationship between confirmation and farmers' continuance intention to residue retention. This study provides a valuable governance reference and scientific basis for the government to adjust and improve existing policies, including how to stimulate farmers to continue to adopt agricultural waste treatment technologies such as residue retention.

The Public's Risk Information Seeking and Avoidance in China During Early Stages of the COVID-19 Outbreak.

This study uses the Planned Risk Information Seeking Model (PRISM) to estimate the public's information seeking and avoidance intentions during the COVID-19 outbreak based on an online sample of 1031 Chinese adults and provides support for the applicability of PRISM framework in the situation of a novel high-level risk. The results indicate that information seeking is primarily directed by informational subjective norms (ISN) and perceived seeking control (PSC), while the main predictors of information avoidance include ISN and attitude toward seeking. Because ISN are the strongest predictor of both information seeking and avoidance, the way the public copes with COVID-19 information may be strongly affected by individuals' social environment. Furthermore, a significant relationship between risk perception and affective risk response is identified. Our results also indicate that people who perceive greater knowledge of COVID-19 are more likely to report greater knowledge insufficiency, which results in less information avoidance.

Impact of media channels and social interactions on the adoption of straw return by Chinese farmers.

Burning crop straws in open fields presents a major threat to the environment in China. To mitigate this problem, numerous methods have been applied. Straw return provides an environmentally friendly and economically sustainable solution to this problem. However, straw return is not popular among Chinese farmers despite the government support for this practice. In this article, the effect of major information sources-media channels and social interactions-on the adoption of straw return. Specifically the interaction between these two information sources is evaluated using survey data from provinces of Hebei, Hubei and Anhui. The main finding is that receiving information from either source increases the probability that a farmer voluntarily adopts the practice of straw return and that the two information sources reinforce each other in promoting the adoption of straw return.

Cognition of agriculture waste and payments for a circular agriculture model in Central China.

An integrated model combining multi-layer cradle to cradle approach: cost effective, technically sound, and bioenvironmental cutting-edge agricultural waste assessment technologies are lacking; to address this gap, the study proposes circular agriculture model (CAM) to support an integrated, bio-based, sustainable and broadly applicable rural society. CAM is an innovative, quasi-public product, bio-commodity, and concept. This study uses survey data on the Chinese province of Hubei to consider the returning of crop residues to the soil and manure for compost or biogas production (first-generation biorefinery). It explores farmers' environmental understanding and their willingness to pay (WTP) under a "polluter pays" principle. Factors, including education, infrastructure, trust in family-neighbors, and environmental attitudes, have a significant effect on WTP. Moreover, income, sustainability-recycling behavior, environmental perception, perceived usefulness-easiness, and trust-in-government positively affect farmers' WTP, whereas environmental attitude, intention, and selfishness have a negative effect. It, therefore, calls for the integration and cooperation of private, government, business, R&D and public welfare to value the combined rural traditions, religion, philosophy and belief, socio-psychological and altruistic values of local communities, which are essential for building trust and providing ecological security, tech spill-over, thereby indirectly helping farmers to restore their livelihoods.