Segmentation of SED by Boundary Flows Associated With Westward Drifting Partial Ring current

The segmentation mechanism of polar cap patches is agreed to be related to temporal changes of interplanetary magnetic field or transient reconnection. In this letter, using Global Ionosphere Thermosphere Model driven by two‐way coupled Block‐Adaptive‐Tree‐Solarwind‐Roe‐Upwind‐Scheme and Rice Convection Model, a new segmentation mechanism is proposed. This mechanism works as follows: A strong boundary flow between the Region 1 and Region 2 field‐aligned currents develops, while a shielding process develops in the inner magnetosphere. As the partial ring current drifts westward, the peak of the boundary flow also moves westward. This strong boundary flow raises the ion temperature through enhanced frictional heating, enhances the chemical recombination reaction rate, and reduces the electron density. When this boundary flow crosses the storm‐enhanced density (SED) plume, the plume will be segmented into patches. No external interplanetary magnetic field variations or transient reconnections are required in this mechanism.Key PointsBoundary flows between Region 1 and Region 2 FACs segment SED plume into patchesLocalized plasma loss is due to enhanced frictional heating within boundary flowsNo external IMF direction change is needed in this segmentation scenarioPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151263/1/grl59354.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151263/2/grl59354-sup-0006-Text_SI-S01.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151263/3/grl59354_am.pd

Two-sided jumps risk model with proportional investment and random observation periods

In this paper, we consider a two-sided jumps risk model with proportional investments and random observation periods. The downward jumps represent the claim while the upward jumps represent the random returns. Suppose an insurance company invests all of their surplus in risk-free and risky investments in proportion. In real life, corporate boards regularly review their accounts rather than continuously monitoring them. Therefore, we assume that insurers regularly observe surplus levels to determine whether they will ruin and that the random observation periods are exponentially distributed. Our goal is to study the Gerber-Shiu function (i.e., the expected discounted penalty function) of the two-sided jumps risk model under random observation. First, we derive the integral differential equations (IDEs) satisfied by the Gerber-Shiu function. Due to the difficulty in obtaining explicit solutions for the IDEs, we utilize the sinc approximation method to obtain the approximate solution. Second, we analyze the error between the approximate and explicit solutions and find the upper bound of the error. Finally, we discuss examples of sensitivity analysis

Secured Data Transmission Over Insecure Networks-on-Chip by Modulating Inter-Packet Delays

As the network-on-chip (NoC) integrated into an SoC design can come from an untrusted third party, there is a growing risk that data integrity and security get compromised when supposedly sensitive data flows through such an untrusted NoC. We thus introduce a new method that can ensure secure and secret data transmission over such an untrusted NoC. Essentially, the proposed scheme relies on encoding binary data as delays between packets travelling across the source and destination pair. The maximum data transmission rate of this inter-packet-delay (IPD)-based communication channel can be determined from the analytical model developed in this article. To further improve the undetectability and robustness of the proposed data transmission scheme, a new block coding method and communication protocol are also proposed. Experimental results show that the proposed IPD-based method can achieve a packet error rate (PER) of as low as 0.3% and an effective throughput of $\boldsymbol {2.3\times 10^{5}}$ b/s, outperforming the methods of thermal covert channel, cache covert channel, and circuit-based encryption and, thus, is suitable for secure data transmission in unsecure systems

Numerical Method for a Risk Model with Two-Sided Jumps and Proportional Investment

In this paper, we consider a risk model with two-sided jumps and proportional investment. The upward jumps and downward jumps represent gains and claims, respectively. Suppose the company invests all of its surplus in a certain proportion in two types of investments, one is risk-free (such as bank accounts) and the other is risky (such as stocks). Our aim is to find the optimal admissible strategy (including the optimal dividend rate and the optimal ratio of investment in risky assets), to maximize the dividend value function, and discuss the effects of a number of parameters on dividend payments. Firstly, the HJB equation of the dividend value function is obtained by the stochastic analysis theory and the dynamic programming method, and the optimal admissible strategy is obtained. Since the integro-differential equation satisfied by the dividend value function is difficult to solve, we turn to the sinc numerical method to approximate solve it. Then, the error between the exact solution (ES) and the sinc approximate solution (SA) is analyzed. Finally, the relative error of a special numerical solution and an ES is given, and some examples of sensitivity analysis are discussed. This study provides a theoretical basis for insurance companies to prevent risks better

Hemispheric Asymmetries in the Mid‐latitude Ionosphere During the September 7–8, 2017 Storm: Multi‐instrument Observations

Hemispheric asymmetries of the Vertical Total Electron Content (VTEC) were observed during the first recovery phase of the geomagnetic storm on September 7–8, 2017. These asymmetries occurred at the mid latitudes at two different local times simultaneously: In the European‐African sector (early morning), the storm time VTEC in the southern/northern hemisphere was higher/lower than the quiet time value, suggesting the southern/northern hemisphere entered the positive/negative phase (N−S+). In the East Asian‐Australian sector (afternoon), the storm time VTEC change was positive in the northern hemisphere, but negative in the southern hemisphere (N+S−). The electron density profiles from digisondes demonstrated that the asymmetries appeared in the F region density as well. The plasma drifts data from digisondes, the column‐integrated [O]/[N2] ratio from GUVI onboard the TIMED satellite, and the detrended VTEC were utilized to study the drivers of the asymmetries. Traveling Ionospheric Disturbance (TID) signatures were identified in the digisonde drift and detrended VTEC data before the appearance of the asymmetry. The magnitude of TIDs was larger in the hemisphere where the negative phase occurred later. The storm time [O]/[N2] ratio change was positive in Africa (S+) and negative in Europe (N−). However, the [O]/[N2] measurements were not available in the East Asian‐Australian sector during the focused period. The hemispheric differences in the vertical drifts were also observed in both sectors. Therefore, the observed hemispheric asymmetries in both sectors are suggested to be due to the hemispheric asymmetries in the thermospheric composition change, vertical drift, and TID activity.Key PointsHemispheric asymmetries of the mid‐latitude ionosphere were observed during the first recovery phase of the September 7–8, 2017 stormHemispheric asymmetries were opposite over the European‐African and East Asian‐Australian sectors simultaneouslyTheir formation is likely due to the asymmetries of the thermospheric composition change, vertical plasma drift, and Traveling Ionospheric Disturbance activityPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/167525/1/jgra56400.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/167525/2/2020JA028829-sup-0001-Supporting_Information_SI-S01.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/167525/3/jgra56400_am.pd

Exploring goodness of prosody by diverse matching templates

Abstract In automatic speech grading systems, rare research is followed through addressing the issue of GOR (Goodness Of pRosody). In this paper we propose a novel method by taking the advantage of our QBH (Query By Humming) techniques in 2008 MIREX evaluation task. A set of standard samples related to the top-cream students are initially picked up as templates, a cascade QBH structure is then taken from two metrics: the MOMEL stylization followed by DTW distance; the Fujisaki model followed by EMD distance. Sentence GOR is obtained by the fused confidence between target and each template, and forms a weighted sum as the goodness in the passage level. Experiment results indicate that performance increases with the count of template, and Fujisaki-EMD metric outperforms MOMEL-DTW one in terms of correlation. Their combination can be treated as template based GOR score, compensated with our previous feature based GOR score, the approach can achieve 0.432 in correlation and 17.90% in EER in our corpus

Changes in Land-Use and Ecosystem Service Value in Guangdong Province, Southern China, from 1990 to 2018

Land-use/cover is one of the major factors that affect the ecosystem and the services it provides. The impact of land-use change on ecosystem service value is a hotspot in developing countries, especially China—a region with rapid economic development and rapid population growth. As the leading area of China’s reform and opening-up, Guangdong province in southern China is subjected to land-use conversion that significantly alters the capacity of natural ecosystem to provide ecosystem services supporting human well-being. We analyzed the characteristics of land-use changes from 1990 to 2018 using the four-phase land-use data interpreted from Landsat satellite images. We estimated the ecosystem service value through a well-established benefit transfer method using modified local value coefficients, analyzed the trade-offs and synergies among ecosystem services through ecosystem service trade-off degree, and compared the relationship between ecosystem services value, economic development, and population in Guangdong province. The results indicated that the following: (1) Built-Up Area drastically expanded from 6783.1 km2 in 1990 to 13,142.0 km2 in 2018 (93.7%), especially in the Pearl River Delta, where the growth rate of Built-Up Area expansion was up to 169.0%. The other land-use types were all contracted as Cropland (−10.9%), Forestland (−1.0%), Grassland (−4.0%), Water Body (−2.1%), and Unused Land (−24.4%). (2) Total ecosystem service value decreased from US$121,666 billion in 1990 to US$116,432 billion in 2018 (−4.3%). Cropland, Forestland, and Water Body played the most important roles for the total ecosystem service value. Water supply experienced the largest declines in ecosystem services value (US$ −1866.3 million, −10.1%), followed by waste treatment (7.6%) and gas regulation (−4.9%). (3) Synergy was the dominant relationship among ecosystem services. The above results can not only serve as reference case for other provinces/regions/countries/ to carry out relevant research work but also provide much focus on land-use planning to manage the impacts of land-use change on regional ecosystem services function

Line-Structured Light Fillet Weld Positioning Method to Overcome Weld Instability Due to High Specular Reflection

Fillet welds of highly reflective materials are common in industrial production. It is a great challenge to accurately locate the fillet welds of highly reflective materials. Therefore, this paper proposes a fillet weld identification and location method that can overcome the negative effects of high reflectivity. The proposed method is based on improving the semantic segmentation performance of the DeeplabV3+ network for structural light and reflective noise, and, with MobilnetV2, replaces the main trunk network to improve the detection efficiency of the model. To solve the problem of the irregular and discontinuous shapes of the structural light skeleton extracted by traditional methods, an improved closing operation using dilation in a combined Zhang-suen algorithm was proposed for structural light skeleton extraction. Then, a three-dimensional reconstruction as a mathematical model of the system was established to obtain the coordinates of the weld feature points and the welding-torch angle. Finally, many experiments on highly reflective stainless steel fillet welds were carried out. The experimental results show that the average detection errors of the system in the Y-axis and Z-axis are 0.3347 mm and 0.3135 mm, respectively, and the average detection error of the welding torch angle is 0.1836° in the test of a stainless steel irregular fillet weld. The method is robust, universal, and accurate for highly reflective irregular fillet welds

PLC based automatic monitoring and its application in the rainwater storage capacity of the roof greening ecosystem.

Objective Green roof can reduce and delay the runoff peak of rainstorm through vegetation mitigation and soil media retention. Real time monitoring of rainfall amount, water content of soil media, and runoff are of great significance for scientific research on rainwater retention capacity of roof greening. Method Taking programmable logic controller (PLC) as the core component of hardware control and combining with touch screen, an automatic monitoring system for the rainwater storage effect of roof greening was developed to automatically monitor rainfall events, rainfall amount, air temperature, air humidity and wind speed. Result The measurement results of the real-time monitoring system were consistent with the data of the meteorological department, which indicates that the system can effectively realize the automatic measurement of the overflow amount and the relative humidity of the substrate soil. There were differences in the overflow amount of plant trough and the relative humidity of substrate soil among different vegetations. For example, in a continuous rainfall period during the test, the retention rate of Portulaca grandiflora trough system was 54.75%, the Sphagneticola trilobata system was only 26.63%, and the Sedum lineare system was 38.34%. There were seasonal differences in the water holding capacity of the substrate. The relative humidity of the substrate generally reached more than 70% after the rainfall in August, while the relative humidity of the substrate of Sphagneticola trilobata system was lower than 70% in September, and even lower in October.Conclusion The monitoring system can realize effective, accurate and real-time dynamic monitoring of storage efficiency of outdoor roof greening and ecological environment factors. The rainwater retention capacity, runoff yield characteristics and water retention performance of the matrix soil of the roof plant trough system may be closely related to the meteorological and climatic conditions, rainfall intensity, rainfall amount, plant types, seasonal changes, matrix composition, etc