Weighted AdaGrad with Unified Momentum

Integrating adaptive learning rate and momentum techniques into SGD leads to a large class of efficiently accelerated adaptive stochastic algorithms, such as Nadam, AccAdaGrad, \textit{etc}. In spite of their effectiveness in practice, there is still a large gap in their theories of convergences, especially in the difficult non-convex stochastic setting. To fill this gap, we propose \emph{weighted AdaGrad with unified momentum}, dubbed AdaUSM, which has the main characteristics that (1) it incorporates a unified momentum scheme which covers both the heavy ball momentum and the Nesterov accelerated gradient momentum; (2) it adopts a novel weighted adaptive learning rate that can unify the learning rates of AdaGrad, AccAdaGrad, Adam, and RMSProp. Moreover, when we take polynomially growing weights in AdaUSM, we obtain its $\mathcal{O}(\log(T)/\sqrt{T})$ convergence rate in the non-convex stochastic setting. We also show that the adaptive learning rates of Adam and RMSProp correspond to taking exponentially growing weights in AdaUSM, which thereby provides a new perspesctive for understanding Adam and RMSProp. Lastly, comparative experiments of AdaUSM against SGD with momentum, AdaGrad, AdaEMA, Adam, and AMSGrad on various deep learning models and datasets are also provided

The effect of cooling rate on the wear performance of a ZrCuAlAg bulk metallic glass

In the present work, the local atomic ordering and the wear performance of ZrCuAlAg bulk metallic glass (BMG) samples with different diameters have been studied using transmission electron microscopy (TEM) plus autocorrelation function analysis, and pin-on-disc dry sliding wear experiments. Differential scanning calorimetry and TEM studies show that smaller diameter BMG sample has higher free volume and less local atomic ordering. The wear experiments demonstrate that with the same chemical composition, the smaller BMG sample exhibits higher coefficient of friction, higher wear rate, and rougher worn surface than those of the larger ones. Compared with larger BMG sample, the faster cooling rate of the smaller sample results in looser atomic configuration with more free volume, which facilitates the formation of the shear bands, and thus leads to larger plasticity and lower wear resistance. The results provide more quantitative understanding on the relationship among the cooling rate, the local atomic ordering, and the wear performance of BMGs

Cronkhite-Canada syndrome associated with rib fractures: a case report

<p>Abstract</p> <p>Background</p> <p>Cronkhite-Canada syndrome (CCS) is a rare multiple gastrointestinal polyposis. Up till now, many complications of CCS have been reported in the literature, but rib fracture is not included.</p> <p>Case Presentation</p> <p>We report a case of a 58-year-old man who was admitted to our hospital with a 6-month history of frequent diarrhea, intermittent hematochezia and a weight loss of 13 kg. On admission, physical examination revealed alopecia of the scalp, hyperpigmentation of the hands and soles, and dystrophy of the fingernails. Laboratory data revealed hypocalcaemia and hypoproteinemia. Esophagogastroduodenoscopy, video capsule endoscopy and colonoscopy revealed various sizes of generalized gastrointestinal polyps. Histological examination of the biopsy specimens obtained from the stomach and the colon showed adenomatous polyp and inflammatory polyp respectively. Thus, a diagnosis of CCS was made. After treatment with corticosteroids for 24 days and nutritional support for two months, his clinical condition improved. Two months later, he was admitted to our hospital for the second time with frequent diarrhea and weight loss. The chest radiography revealed fractures of the left sixth and seventh ribs. Examinations, including emission computed tomography, bone densitometry test, and other serum parameters, were performed, but could not identify the definite etiology of the rib fractures. One month later, the patient suffered from aggravating multiple rib fractures due to the ineffective treatment, persistent hypocalcaemia and malnutrition.</p> <p>Conclusions</p> <p>This is the first case of a CCS patient with multiple rib fractures. Although the association between CCS and multiple rib fractures in this case remains uncertain, we presume that persistent hypocalcaemia and malnutrition contribute to this situation, or at least aggravate this rare complication. Besides, since prolonged corticosteroid therapy will result in an increased risk of osteoporotic fracture, CCS patients who accept corticosteroid therapy could be potential victims of rib fracture.</p

A Novel Traffic Obfuscation Technology for Smart Home

With the widespread popularity of smart home devices and the emergence of smart home integration platforms such as Google, Amazon, and Xiaomi, the smart home industry is in a stage of vigorous development. While smart homes provide users with convenient and intelligent living, the problem of smart home devices leaking user privacy has become increasingly prominent. Smart home devices give users the ability to remotely control home devices, but they also reflect user home activities in traffic data, which brings the risk of privacy leaks. Potential attackers can use traffic classification technology to analyze traffic characteristics during traffic transmission (e.g., at the traffic exit of a smart home gateway) and infer users’ private information, such as their home activities, causing serious consequences of privacy leaks. To address the above problems, this paper focuses on research on privacy protection technology based on traffic obfuscation. By using traffic obfuscation technology to obscure the true traffic of smart home devices, it can prevent malicious traffic listeners from analyzing user privacy information based on traffic characteristics. We propose an enhanced smart home traffic obfuscation method called SHTObfuscator (Smart Home Traffic Obfuscator) based on the virtual user technology concept and a virtual user behavior construction method based on logical integrity. By injecting traffic fingerprints of different device activities into the real traffic environment of smart homes as obfuscating traffic, attackers cannot distinguish between the real device working status and user behavior privacy in the current home, effectively reducing the effect of traffic classification attack models. The protection level can be manually or automatically adjusted, achieving a balance between privacy protection and bandwidth overhead. The experimental results show that under the highest obfuscation level, the obfuscation method proposed in this paper can effectively reduce the classification effect of the attack model from 95% to 25%

Influence of Artificial Aging Time on Microstructures and Mechanical Properties of Porthole Die Extruded 6063 Aluminum Alloy

The influence of artificial aging time on the microstructures and mechanical properties of the 6063 aluminum alloy profile extruded by porthole die was investigated through hardness testing, expansion testing, scanning electron microscope (SEM), and transmission electron microscope (TEM). The results showed that the artificial aging time had a significant impact on the size, morphology, distribution of precipitated phases, and mechanical properties of the porthole die extruded 6063 aluminum alloy profiles. As the artificial aging time increased, the second phase particles gradually precipitated, and the precipitation strengthening gradually enhanced, resulting in an increase in the hardness of the profile. The hardness of the welding zone was lower than that of the matrix zone. Compared with the precipitation in the matrix zone, the size and distribution of the precipitates were uneven, and the time for the precipitation was long in the welding zone due to the influence of grain size. The width of the precipitate free zone (PFZ) in the welding zone was greater than that in the matrix zone. The expansion ratio decreased with the increase of aging time, which indicated that the artificial aging treatment was adverse to the plastic deformation ability of the profiles

New U Pb zircon age and petrogenesis of the plagiogranite, Troodos ophiolite, Cyprus

The Troodos ophiolite is a classic and is one of the most complete and best-studied ophiolites on Earth. However, there are few studies on the geochronology of the plagiogranite in the Troodos ophiolite. With the advancement of zircon U-Pb in situ dating method developed in recent decades, it is necessary to revisit the age of the plagiogranite. In this study, we carried out detailed petrography, zircon U-Pb dating and mineral compositional analysis for the plagiogranite. Our new zircon ages of ~90–91 Ma confirm the previous age data. Our findings also offer new perspectives on the petrogenesis of the Troodos plagiogranite. It is common that some of the Troodos plagiogranite outcrops show intense “epidotization”. The Troodos plagiogranite can thus be divided into epidote-free plagiogranite and epidote plagiogranite. Zircons in the epidote plagiogranite have mottled texture with high contents of most elements (especially for P, Y, REEs, Nb and Ta), which differs distinctly from those in the epidote-free plagiogranite with a clean appearance and oscillatory zoning. The two types of zircons all having high Th/U ratio (0.25–1.46 with an average of 0.69) are consistent with being of magmatic origin. The texture and composition of zircons from the epidote plagiogranite suggest that they are crystallized from a highly dissolving agent that transforms existing minerals such as plagioclase and amphiboles while concentrating rare earth elements (REEs) and high field strength elements (HFSEs, including Nb, Ta, Ti, Zr, Hf, Th and U4+) to precipitate accessory minerals such as zircon and titanite as well as the more abundant epidote. The intergrowth of quartz and skeletal plagioclase together with the precipitation of zircon, titanite and epidote indicates that the highly dissolving agent is best understood as late-stage magmatic fluid or more likely supercritical fluid/melt whose nature and origin deserve further investigation

Origin of magmatic harzburgite as a result of boninite magma evolution - An illustration using layered harzburgite-dunite cumulate from the Troodos ophiolite complex

Olivine (Ol) and orthopyroxene (Opx) are the primary liquidus phases of boninite in modern subduction settings and in many ophiolite complexes. It is thus straightforward to expect the formation of harzburgite cumulate resulting from boninite magma evolution. However, such magmatic harzburgite has been rarely studied. Here, we report the results of our study on such harzburgite from the Troodos ophiolite complex. The Troodos cumulate harzburgite (locally lherzolite) is characteristically interlayered with dunite, showing varying thickness on millimeter to decimeter scales, as the result of volumetrically varying multiple pulses of melt injection into the evolving magma chamber. We illustrate the development of the interlayered cumulate by phase equilibrium analysis. The parental melt of each pulse begins to crystallize olivine to form a dunite layer before reaching the Ol-Opx cotectic, along which Ol and Opx coprecipitate to form a harzburgite layer. Periodical replenishment will result in dunite-harzburgite interlayered cumulate. In cases when replenishment may be delayed, the melt along the Ol-Opx cotectic can evolve to the Ol-Opx-clinopyroxene (Cpx) eutectic to form harzburgite with some Cpx or lherzolite. The calculated melts in equilibrium with spinels in the cumulate are characteristic of boninite in major element compositional spaces. The calculated melts in equilibrium with Cpx and Opx in the cumulate share the same as, or identical to, trace element patterns of the Troodos boninite (both glasses and bulk-rock compositions). Petrological modeling of the boninite magma evolution shows a crystallization order of Ol, Opx, Cpx, plagioclase. Our study also emphasizes the importance in considering dunite-harzburgite/lherzolite cumulate when interpreting seismic structure of the crust in subduction settings, especially in rock sequences associated with subduction initiation thought to be indicated by boninite magmatism

Present-day temperature–pressure field and its implications for the geothermal resources development in the Baxian area, Jizhong Depression of the Bohai Bay Basin

The Baxian area in the Jizhong Depression, west of the Bohai Bay Basin, is rich in geothermal resources, where Xiong County was built as the first smokeless city in China and the Xiong-county Model has become the geothermal resources demonstration model in China. In this study, the present-day geothermal gradient and the horizontal distribution characteristics of the temperature and pressure at different depths in the Baxian area were studied based on massive measured temperature and pressure data of the boreholes, and then the relationship was also discussed between the temperature–pressure field and the geothermal resources. The following findings were obtained. (1) The present-day geothermal gradient of the Baxian area is within the range of 21.8–73.5 °C/km, averaging 33.5 °C/km. (2) Its strata temperature increases as the depth increases. The horizontal variations of the geothermal gradient and strata temperature correspond to the basement relief very well. As the abnormally high temperature areas, the northern Niutuozhen Uplift, the Central Baxian Depression and the central East Langgu Depression possess huge geothermal resources and will be the most favorable exploration targets. (3) The formation pressure of the Baxian area is characterized by normal pressure and weak overpressure, and its horizontal distribution varies at different depths. The middle–strong overpressure generally developed at the depth of 4000 m in the southern Langgu Depression and southern Baxian Depression. This study is of important guiding significance for the exploration and development of geothermal resources in the Baxian area. Keywords: Bohai Bay Basin, Jizhong Depression, Baxian area, Geothermal resources, Temperature, Pressure, Geothermal gradient, Abnormally high temperature area, Overpressur