Performance Evaluation of Low-Cost Dual-Frequency GNSS Receivers for Precise Positioning in Senegal: Issues and Challenges

The development of this technology has favored the advances noted in recent years in the field of precise positioning. It has also paved the way for a wide range of research into the evaluation of their performance and reliability, their potential use in different fields, the improvement of performance and combined systems, etc. Single-frequency GNSS receivers, which for a long time remained the only category of low-cost GNSS receivers, often limited by their level of accuracy (metric) mainly due to their single-frequency nature, have been joined in the last decade by dual-frequency GNSS receivers developed by certain manufacturers of positioning equipment. These receivers now offer possible alternatives to the relatively expensive conventional (topographic quality) or geodetic receivers and. In this study, the performance of these low-cost dual-frequency receivers was evaluated in static and real-time kinematic GNSS positioning modes. Static positioning was carried out on three points with sessions of 2 h and 4 h over three days with antenna swapping (CHC i50, Leica GS14 and Emlid Reach RS2+). Real-time observations were carried out on eleven (11) points in open, poorly open and not at all open environments, in order to assess not only performance but also receiver sensitivity in environments with a high risk of multipath. The results obtained showed an average agreement of 2 cm in planimetry between the low-cost Emlid RS2+ receiver and the Leica GS14 and CHC i50 receivers. The differences in altimetry are nevertheless greater (sometimes up to decimetres for certain points). Real-time positioning results provided an average convergence of around 1 cm on the E, N and H components with the results from the low-cost Emlid Reach RS2+ and Ublox ZED-F9P receivers and the CHC i50 receiver. Analysis of the results obtained has enabled us to highlight the various issues and challenges associated with this new generation of GNSS receivers, with a view to enhancing their appropriation and optimal integration in the professional and research worlds.

Comparative Study on the Policy of Multiplicity Issues in Clinical Trials at Home and Abroad

Objective To study the content of China’s guiding principles on multiplicity issues in clinical trials,and to provide reference for the revision of China’s relevant guiding principles.Methods Based on ICH E9,the similarities and differences of the guiding principles of US Food and Drug Administration(FDA),European Medicines Agency(EMA),and National Medical Products Administration(NMPA)on the multiplicity issues in clinical trials were compared one by one.Results and Conclusion In general,NMPA guidelines are based on ICH E9,but in detail,the guidelines of FDA and EMA focus differently on the multiplicity issues.Therefore,NMPA guidelines need to be detailed and comprehensive.NMPA guidelines can be refined by referring to foreign guidelines to improve the practical guiding significance for clinical research and promote the level of domestic clinical trials in line with international standards.

From Quantitative Issues to Structural Ones: An Interpretation of China's Labor Market

Based on the latest demographic and labor data, this paper reveals the changes in China＇s labor supply and demonstrates that China＇s key employment issues are no longer quantitative contradictions but increasingly have become structural issues related to labor market mismatch. Due to real and potential economic growth rates being consistent, cyclical unemployment is, at least for now, not striking. If traditional policy measures continue to be followed in disregard of frictional and structural attributes of the labor market to increase total employment, not only will China＇s employment issues persist but new labor market problems may arise as well China should focus on addressing structural unemployment contradictions.

Tense and Aspect Issue of Translator Competence

This essay is a research report, which is based on results of grammatical error analysis and interviews with linguistic teachers. These researches are conducted in four language streams, namely, Chinese, Spanish, Korean and Japanese. It will talk about problems identified in all these four language streams, with Chinese as the focus. Although according to various definitions, translation competence includes several parts, which are all required for a professional translator; this essay covers mainly the linguistic competence with tense and aspect issue as the main point. Meanwhile, some major causes of mistakes will be identified, such as interference of mother tongue, lack of second language proficiency. In the end, some possible ways for improvement are presented for reaching what are needed for a professional translator.

The States-of-arts and Key Scientific Issues on Durability Research of Concrete Structures

Concrete has traditionally been regarded as a durable material requiring little or no maintenance. However, over the past several decades, a number of durability related problems have emerged and stimulated research into the factors relating to concrete durability globally. The challenge now facing practicing engineers is how to design and build structures that not only satisfy the specified structural requirements, but also achieve the performance levels required from a durability standpoint. Research works on concrete structural durability have been widely reported in the literature over the last several decades. In this paper, reviews of four stages of research work on durability, i e, environments, materials, components, and structures, were presented. Afterwards, the key scientific issues in this field were also pointed out.

Coal mining in northeast India： an overview of environmental issues and treatment approaches

Northeast India has a good deposit of sub-bituminous tertiary coal. The northeast Indian coals have unusual physico-chemical characteristics such as high sulfur, volatile matter and vitrinite content, and low ash content. In addition, many environmental sensitive organic and mineral bound elements such as Fe, Mg, Bi, AI, V, Cu, Cd, Ni, Pb, and Mn etc. remain enriched in these coals. Such characteristics are associated with more severe environmental impacts due to mining and its utilization in coal based industries. Environmental challenges include large scale landscape damage, soil erosion, loss of forest ecosystem and wildlife habitat, air, water and soil pollution. Several physical and chemical methods are reported in literature for the removal of mineral matter, total sulfur and different forms of sulfur from high sulfur coal in northeast India. This paper may help different researchers and stakeholders to understand current state of research in the field. Initiatives may be taken towards sustainable use of coal resources by adopting innovative clean technologies and by implementing effective control measures and regulatory policies.

Preface to the Special Issue on the “Observation,Prediction and Analysis of severe Convection of China”(OPACC) National “973” Project

China is a country that is frequently affected by severe convective weather. Here, severe convective weather mainly refers to intense local heavy precipitation, thunderstorm-induced gale-force winds including those from tornadoes and downbursts, and hail and lightning. These types of severe weather are usually small in spatial scale and rapid in their development, and are therefore difficult to capture by observational networks and are poorly resolved in typical operational numerical weather prediction （NWP） models. Furthermore, many of the important dynamic and physical processes involved are not well understood. Within China, the impacts of severe convective weather rank only after those of landfalling typhoons and widespread heavy precipitation and flooding. Studies （e.g., Zhang and Zhai, 2011） have shown tendencies for an increased frequency in short-duration extreme precipitation during the past several decades over most of eastern China, where the population is most dense. An in-depth understanding of severe convective weather in China, as well as being able to accurately predict it, is clearly of great importance.

Consideration of some key issues of carbon market development in China

The global carbon market has developed rapidly with two significant trends of globalization and financialization.Deriving economic interest is a nation driven-force behind the international climate negotiation and carbon market.According to deeply analyzed relationships between the carbon market and the key subjects of the climate negotiation,this article reveals that promoting the development of the global carbon market is one of the core interests of developed nations.Based on the background of international carbon market development and domestic carbon market pilots,four suggestions to the key issues of China's carbon market are provided.The first is that the goal of China's carbon market should be in line with and contribute to the national objectives and policies addressing climate change.The second is that the Chinese carbon market should mainly target the emission reduction of production-sectors,and contribute to their upgradation and transformation.The third is mat the development of the nation-wide carbon market in China should first take the principle of unbalanced regional development into consideration.The fourth is that linking China's carbon market to the international market should keep steps in line with international opening-up of China's financing system.

Introduction to Urban and Community Forestry in the United States of America: History, Accomplishments, Issues and Trends

The urban and community forestry movement in the United States has matured over the last 20 years from managing street trees, to understanding the benefits of trees in urban ecosystems, and now to managing urban green infrastructure. This paper introduced the history, development, and major accomplishments of the urban and community forestry movement, highlighted the economic, ecological, environmental, and social values of forests and trees to communities, and discussed issues and trends of the urban and community forestry program in the United States.

北美体育社会问题研究主题的趋势分析——以2007—2011年《Journals of Sports and Social Issues》为例

以内容分析法、文献资料法和逻辑分析法为主要研究方法,通过对《体育和社会问题》(《JSSI》)2007-2011年发表的122篇论文研究主题的归类与分析,对北美体育社会问题研究主题进行了系统研究。研究主要结论:"性别歧视、种族歧视"等参与体育运动权利等方面研究列北美体育社会问题研究的首位;"体育暴力、兴奋剂"等体育运动中的偏差行为研究位居其次。同时,"体育情感、体育认同和体育亚文化"等研究呈现出逐步上升的趋势。

Geological conditions and key rock mechanics issues in the Western Route of South-to-North Water Transfer Project

In terms of special geological conditions of the Western Route of South-to-North Water Transfer Project, the classification method for surrounding rocks is discussed by combining with the construction method of tunnel boring machine （TBM）. The classification standard of surrounding rocks is put forward on the basis of physical simulations and engineering practices. Damage, deformation and evolution of surrounding rocks induced by TBM excavation are discussed. Meanwhile, the long-term deformation mechanisms and stability of surrounding rocks are also studied. On this basis, a three-dimensional constitutive model for interbedded sandstone slate and a fiat shell-joint element-foundation system for calculating internal forces of segment lining are established. The deformation features of surrounding rocks of deep and steep interbedded sandstone slate and their influences on internal forces of segment lining are presented. Finally, the design methods of segment lining constructed in deep and steep flysch are proposed.

Design Issues for Use of Solid State Transmitter Radars in the Terminal Airspace

Abstract

Exploring Greek High School Students’ Understanding of Basic Environmental Issues

The present research studies the knowledge of 221 Ioannina’s city, located in the northwestern region of Greece, high school students on 10 environmental issues. Schoolers’ responses were collected through a “closed response” questionnaire distributed at three of the city’s Public High Schools. The overall picture appeared to be moderately satisfactory, as high schoolers possess a good knowledge on several environmental issues, while misconceptions on other issues, such as sustainable development, predominate. Taking into account the outcome of the present study we consider that improvements are needed in the existing Environmental Education Program in order to ameliorate their knowledge.

Special Issue on "Recent Advances in Power System Control" for International Journal of Control,Automation,and Systems

Today the high quality power supply is of essential in the economic development in a country. With the development of modem power systems and increasing demand for power supply, the electric power industry is facing a great challenge in meeting the increased load demand with highest reliability and security with minimum transmission expenditure. Power system stability analysis and control is one of the most important issues in power systems. The problem becomes more and more serious in power systems with the development of modem power systems. The ability of a power system

mLysPTMpred: Multiple Lysine PTM Site Prediction Using Combination of SVM with Resolving Data Imbalance Issue

Post-translational modification (PTM) increases the functional diversity of proteins by introducing new functional groups to the side chain of amino acid of a protein. Among all amino acid residues, the side chain of lysine (K) can undergo many types of PTM, called K-PTM, such as “acetylation”, “crotonylation”, “methylation” and “succinylation” and also responsible for occurring multiple PTM in the same lysine of a protein which leads to the requirement of multi-label PTM site identification. However, most of the existing computational methods have been established to predict various single-label PTM sites and a very few have been developed to solve multi-label issue which needs further improvement. Here, we have developed a computational tool termed mLysPTMpred to predict multi-label lysine PTM sites by 1) incorporating the sequence-coupled information into the general pseudo amino acid composition, 2) balancing the effect of skewed training dataset by Different Error Cost method, and 3) constructing a multi-label predictor using a combination of support vector machine (SVM). This predictor achieved 83.73% accuracy in predicting the multi-label PTM site of K-PTM types. Moreover, all the experimental results along with accuracy outperformed than the existing predictor iPTM-mLys. A user-friendly web server of mLysPTMpred is available at http://research.ru.ac.bd/mLysPTMpred/.

Preface to the special issue of Dense Array Seismology

Both earthquake seismology and structural seismology rely on observations, which in turn contribute critically to the development of seismology, especially in recent years.In order to understand specific geologic structures and interior processes of the Earth, seismic arrays are widely

Ontology modeling of semantics in social media:Public issue knowledge base (PIKB)of the Weibo

Purpose:This study aims to construct an ontology to model the semantics of social media streams,in particular,trending topics and public issues.Design/methodology/approach:Our knowledge base included 10 public events and topics from Weibo respectively,which were collected through keyword search and a crawler program.We used a semi-automatic approach to model and annotate the semantics in social media,and adapted the multi-layered ontology to refine the design based on previous researches,then we used named entity recognition(NER) to extract entities to instantiate the ontology.Relationships were extracted based on co-occurrence measures.Finally,we manually conducted post-filtering evaluation and edited the extracted entities and relationships.Findings:An initial assessment demonstrated that our multi-layered ontology supports various types of queries and analyses in the public issue knowledge base(PIKB),which can serve as an effective tool to query,understand and trace public issues.Research limitations:Manual involvement cannot meet the requirements for challenges of sustainable developments.Since the relationships extracted are fully based on the co-occurrence of entities,rich semantic relationships,such as how much the key players have been involved,could not be fully reflected.Besides,the user evaluation is necessary for further ontology assessment.Practical implications:The PIKB can be used by regular Web users and policy makers to query,understand,and make sense of public events and topics.The methodology and reusable ontology model are useful for institutions that are interested in making use of the social media data.Originality/value:In this study,a multi-layered ontology is applied to model the evolving semantics of public events and trending topics in social media,and the semi-automatic approach could make it possible to extract entities and relationships from large amount of unstructured short texts of user generated content(UGC) from social media.

Special Issue on Innovative Design of Complex Products

With the development of science and technology as well as the diversification and individualization of market demand,modern products update more and more rapidly.e rapid development of new products to satisfy the increasingly improved and personalized customer demands greatly depends on the progress in the innovative design theory and performance optimization

Impacts of Nontraditional Security Issues on National Security

New changes are taking place in nontraditional security fields,characterized by the increase in confrontation and conflict,the intensification of threats,and diversification.The interconnectivity,unpredictability,and transmissibility of nontraditional security threats are unprecedented.The emergence and even perpetuation of the above-mentioned new features are both attributed to objective factors,such as social development,ideological shifts,and scientific and technological advancement,and are closely related to the moves of certain major countries to instigate the so-called remarkable power competition recklessly and boost geopolitical contest.The rapid resurgence of securitization in global politics is hidden behind the rise of nontraditional security threats.Nontraditional security issues have generally entered a dynamic phase,which exerts an impact on the international security environment and the global landscape.A growing number of countries have emphasized on the realistic and urgent threat of nontraditional security challenges to their national security.These countries have tended to achieve traditional security goals via nontraditional means and tackle nontraditional security challenges with traditional mindsets.Thus,the boundary between traditional and nontraditional security issues is increasingly blurred.The methodology that dichotomizes traditional and nontraditional security issues may no longer be useful during assessments of major threats confronting national security.The connotations of peace and war have significantly changed in the new era.Distinguishing"hot"security issues from"cold"ones or traditional security issues from nontraditional ones is difficult.Such distinction requires consideration of all security issues when recognizing and addressing national security challenges.Thus,these increasingly complex security issues must be analyzed within a wide context of the oncein-a-century changes occurring worldwide and China should pursue a holistic approach to national security as a fundamental principle in response to various threats.

Soil and Water Ecology as the Core Issue of Contemporary Biodiversity Conservation:A Case Study of the Population of Elk,an Endemic Species in China

From a new vision of the theory of soil and water ecology,it is discussed that soil and water ecology is the core issue of contemporary biodiversity protection.First,soil and water ecology constitutes the habitat for biological survival,and is the premise and foundation of biodiversity.Second,soil and water ecology is the material and energy source of biological survival and the prerequisite of biodiversity.Human beings are the beneficiaries and operators of soil and water ecology,which is related to the future and destiny of biodiversity on the earth.It should protect and restore the original,diverse,complete and clean soil and water ecology on the earth from three aspects of protecting pure natural soil and water ecology,protecting and restoring natural soil and water ecology,and building and regenerating artificial soil and water ecology,so as to fundamentally achieve biodiversity protection.