Apparent negative motion of vortex matter due to inhomogeneous pinning

We investigate the transport of vortices in superconductors with inhomgeneous pinning under a driving force. The inhomogeneity of pinning is simplified as strong-weak pinning regions. It is demonstrated that the interactions between the vortices captured by strong pinning potentials and the vortices in the weak pinning region cause absolute negative motion (ANM) of vortices: The vortices which are climbing toward the high barriers induced by the strong pinning with the help of driving force move toward the opposite direction of the force and back to their equilibrium positions in the weak pinning region as the force decreases or is withdrawn. Our simulations reveal that the hysteresis of ANM is determined by the competition between the speed of the negative motion which depends on the piining inhomogeneity in superconductors and the speed of the driving force. Under the conditions of either larger force scanning rate or higher pinning inhomogeneity, a marked ANM and a larger hysteretic speed-force loop could be observed. This indicates that the time window to observe the ANM should be chosen properly. Moreover, the V-1 characteristics of Ag-sheathed Bi=2223 tapes are measured, and experimental observations are qualitatively in agreement with the simulation

Five-Section Trajectory Design of Thick Glutenite Reservoir in Shengli Oilfield

Many blocks of Shengli Oilfield are located in urban areas, and the site selection of well sites is limited. In order to meet the needs of reservoir development and deployment, five-section trajectory is increasingly used. Difficulty in site selection results in directional well development, and reservoir deployment requires vertical well development. In order to resolve the two contradictions, five-section trajectory is used in the well design, and vertical drilling after hitting the target. The problems with this type of trajectory are high torque drag and easier fatigue of the drilling pipe. When the displacement is small, the effect is small. When the displacement is large, it will cause engineering complexity such as difficulty drilling weight transfer and fatigue of drilling pipe. Aiming at the shortcomings of the five-section trajectory, with the help of existing drill string force analysis software, the parameters of the five-section trajectory were analyzed, and reasonable values were recommended to provide an optimization idea for the five-section trajectory

JDsearch: A Personalized Product Search Dataset with Real Queries and Full Interactions

Recently, personalized product search attracts great attention and many models have been proposed. To evaluate the effectiveness of these models, previous studies mainly utilize the simulated Amazon recommendation dataset, which contains automatically generated queries and excludes cold users and tail products. We argue that evaluating with such a dataset may yield unreliable results and conclusions, and deviate from real user satisfaction. To overcome these problems, in this paper, we release a personalized product search dataset comprised of real user queries and diverse user-product interaction types (clicking, adding to cart, following, and purchasing) collected from JD.com, a popular Chinese online shopping platform. More specifically, we sample about 170,000 active users on a specific date, then record all their interacted products and issued queries in one year, without removing any tail users and products. This finally results in roughly 12,000,000 products, 9,400,000 real searches, and 26,000,000 user-product interactions. We study the characteristics of this dataset from various perspectives and evaluate representative personalization models to verify its feasibility. The dataset can be publicly accessed at Github: https://github.com/rucliujn/JDsearch.Comment: Accepted to SIGIR 202

Selling the Data Product: Pricing Strategies and Welfare Implications

This paper examines the pricing and welfare implications of data as a factor of production with a stylized economic model. We introduce a generalized framework that specifies two types of data: 1) public data pricing, which maximizes social welfare, and 2) commercial data pricing, which maximizes the profit. The model reveals two takeaways: first, two prices may converge in the data economy. It is due to that data come from citizens and may be used to create value back to them. Therefore, a profit- seeking data seller might find it optimal to extend the user base, which is in line with the interest of the welfare maximizer. Second, the pricing gap between optimal prices does not change monotonically with the improvement of data quality. These findings shed new light on the current and future of data product operations, particularly in the understudied public sectors

Combined cloud:a mixture of voluntary cloud and reserved instance marketplace

Voluntary cloud is a new paradigm of cloud computing.It provides an alternative selection along with some well-provisioned clouds.However,for the uncertain time span that participants share their computing resources in voluntary cloud,there are some challenging issues,i.e.,fluctuation,under-capacity and low-benefit.In this paper,an architecture is first proposed based on Bittorrent protocol.In this architecture,resources could be reserved or requested from Reserved Instance Marketplace and could be accessed with a lower price in a short circle.Actually,these resources could replenish the inadequate resource pool and relieve the fluctuation and under-capacity issue in voluntary cloud.Then,the fault rate of each node is used to evaluate the uncertainty of its sharing time.By leveraging a linear prediction model,it is enabled by a distribution function which is used for evaluating the computing capacity of the system.Moreover,the cost optimization problem is investigated and a computational method is presented to solve the low-benefit issue in voluntary cloud.At last,the system performance is validated by two sets of simulations.And the experimental results show the effectiveness of our computational method for resource reservation optimization

The Fangshan/Family-based Ischemic Stroke Study In China (FISSIC) protocol

Background: The exact etiology of ischemic stroke remains unclear, because multiple genetic predispositions and environmental risk factors may be involved, and their interactions dictate the complexity. Family-based studies provide unique features in design, while they are currently underrepresented for studies of ischemic stroke in developing countries. The Fangshan/Family-based Ischemic Stroke Study In China (FISSIC) program aims to conduct a genetic pedigree study of ischemic stroke in rural communities of China. Methods/Design: The pedigrees of ischemic stroke with clear documentation are recruited by using the proband-initiated contact method, based on the stroke registry in hospital and communities. Blood samples and detailed information of pedigrees are collected through the health care network in the rural area, and prospective follow-up of the pedigrees cohort is scheduled. Complementary strategies of both family-based design and matched case-spousal control design are used, and comprehensive statistical methods will be implemented to ascertain potential complex genetic and environmental factors and their interactions as well. Discussion: This study is complementary to other genetic pedigree studies of ischemic stroke, such as the Siblings With Ischemic Stroke Study (SWISS), which are established in developed countries. We describe the protocol of this family-based genetic epidemiological study that may be used as a new practical guideline and research paradigm in developing countries and facilitate initiatives of stroke study for international collaborations.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000250034100001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Genetics & HereditySCI(E)PubMed7ARTICLE60