11 research outputs found
An Efficient Cooperative Framework for Multi-Query Processing over
Abstract. XML is a de-facto standard for exchanging and presenting information on the Web. However, XML data is also recognized as verbose since it heavily inflates the size of the data due to the repeated tags and structures. The data verbosity problem gives rise to many challenges of conventional distributed database technologies. In this paper, we study the XML dissemination problem over the Internet, where the speed of information delivery can be rather slow in a server-client architecture which consists of a large number of geographically spanned users who access a large amount of correlated XML information. The problem becomes more severe when the users access closely related XML fragments, and in this case the usage of bandwidth is inefficient. In order to save bandwidth and process the queries efficiently, we propose an architecture that incorporates XML compression techniques and exploits the results of XPath containment. Within our framework, we demonstrate that the loading of the server is reduced, the network bandwidth can be more efficiently used and, consequently, all clients as a whole can benefit due to savings of various costs.
Tutorial on big spectrum data analytics for space information networks
Abstract Space information network (SIN) is an integrated network system of various space information platforms (e.g., satellites, stratospheric airships, manned or unmanned aerial vehicles) to enable real-time sensing, collection, transmission, and processing of various space information, as well as to realize both global and localized tailor-made systematized information services. Spectrum usage and management becomes a more and more serious issue in SIN mainly for the following reasons: (i) the paradox between spectrum shortage and spectrum under-utilization, (ii) the complex electromagnetic spectrum environment with tremendous spectrum devices and ubiquitous spectrum interference, and (iii) the spectrum disorder and spectrum attack. In this paper, we propose to empower SIN with big spectrum data analytics for dynamic spectrum sharing, real-time spectrum monitoring, and intelligent spectrum control. Specifically, we first identify critical spectrum issues in developing SIN and highlight that spectrum data analytics is the key solution to address these issues via spectrum sensing, spectrum data statistical inference and knowledge discovery, spectrum data-driven decision optimization, and spectrum experiment validation and evaluation, etc. Then, we introduce the concept of big spectrum data in SIN and analyze its characteristics, including volume, value, variety, viability, veracity, and velocity. Next, we discuss the emerging use cases and highlight research frontiers
Multi-query evaluation over compressed XML data in DaaS
This paper addresses the problem of evaluating a heavy load of subscribed queries (or simply multi-queries) over compressed XML data in a distributed service-oriented DaaS (Database as a Service) environment. We propose a holistic approach that evaluates complex queries over a compressed document and forwards the compressed results directly to the data requestor (DR). Firstly, we review the data management issues in DaaS, and then we will address the multi-queries optimization problem. Secondly, we introduce a new rewriting translation technique to decompose and reorganize a complex query into its corresponding Structure of complex XPath (SXP). Following this, multi-query evaluation is performed based on the containment relationships between the queries. The containment relationships are exploited by a global data structure, the Structural-Query-Index Tree (SQIT), which supports prefix sharing among the submitted queries. The experimental results demonstrate that the proposed approach obtains higher query processing efficiency than traditional ones. © Springer-Verlag Berlin Heidelberg 2011
Identifying the Influencing Factors of Plastic Film Mulching on Improving the Yield and Water Use Efficiency of Potato in the Northwest China
Potato is an important crop in the Northwest China, however, its production is constrained by water scarcity. Plastic mulching film is an efficient technical measure to alleviate potato production restrictions. Therefore, studying the response of potato yield and water use efficiency to plastic mulching film is of great significance. The study conducted a meta-analysis to quantify the effect of plastic film on potato yield and water use efficiency in the Northwest. The study then quantified the effects of different levels of natural conditions (mean annual precipitation, mean annual accumulated temperature ≥ 10 °C), fertilizer application (nitrogen fertilizer, phosphate fertilizer, potassium fertilizer), cultivation measures (planting density, cultivation method, mulching method), and mulching properties (mulching color, mulching thickness) through subgroups analysis. Finally, the random forest model was used to quantify the importance of factors. Plastic film mulching increased yield by 27.17% and water use efficiency by 27.16%, which had a better performance under relatively lower mean annual precipitation, low mean annual accumulated temperature ≥ 10 °C, relatively lower fertilizer application, planting density of 15,000–45,000 plants·ha−1, ridge, and black mulching. Natural conditions, fertilization measures were vital to improve productivity. The research results can provide reference for agricultural management strategies of potato cultivation using plastic film in the Northwest China and other potato-producing areas
Clinical features and transmission risk analysis of dengue virus infections in Shenzhen, During 2014–2019
Dengue fever (DF) and dengue hemorrhagic fever (DHF) are among the most common tropical diseases affecting humans. To analyze the risk of clinical and transmission of DF/DHF in Shenzhen, the surveillance on patients of all-age patients with dengue virus (DENV) infections was conducted. Our findings revealed that the majority of DENV-infected patients are young to middle-aged males, and the development of the disease is accompanied by abnormal changes in the percentages of neutrophils, lymphocytes, and basophils. Demographic analysis revealed that these patients is concentrated in areas such as Futian District, which may be due to the higher mosquito density and temperature than that in other area. Subsequent, mosquito infection experiments confirmed that the effect of temperature shift on DENV proliferation and transmission. Not only that, constant temperatures can enhance the spread of DENV, even increase the risk of epidemic. Thus, the role of innate immune response should be highlighted in the prediction of severe severity of DENV-infected patients, and temperature should be taken into account in the prevention and control of DENV. Introduction: Dengue fever (DF) and dengue hemorrhagic fever (DHF) are among the most common tropical diseases affecting humans, and which caused by the four dengue virus serotypes (DENV 1–4). Objectives: To analyze the risk of clinical and transmission of DF/DHF in Shenzhen. Methods: The surveillance on patients of all-age patients with dengue virus (DENV) infections was conducted. Results: Our findings revealed that the majority of DENV-infected patients are young to middle-aged males, and the development of the disease is accompanied by abnormal changes in the percentages of neutrophils, lymphocytes, and basophils. Demographic analysis revealed that these patients is concentrated in areas such as Futian District, which may be due to the higher mosquito density and temperature than that in other area. Subsequent, mosquito infection experiments confirmed that the effect of temperature shift on DENV proliferation and transmission. Not only that, constant temperatures can enhance the spread of DENV, even increase the risk of epidemic. Conclusion: 1. Elevated levels of neutrophils, lymphocytes, basophils, and temperature are all significant risk factors for dengue transmission and pathogenesis; 2. Temperature increasing is associated with a higher risk of dengue transmission; 3. Fluctuations in temperature around 28 °C (28 ± 5 °C) would increase dengue transmission