Growing client population, ever-increasing service demand, and complexity of services are the driving factors for the mobile operators for a paradigm shift in their core technology and radio access networks. 5G mobile...Growing client population, ever-increasing service demand, and complexity of services are the driving factors for the mobile operators for a paradigm shift in their core technology and radio access networks. 5G mobile network is the result of this paradigm shift and currently under deployment in many developed countries such as United States, United Kingdom, South Korea, Japan, and China—to name a few. However, most of the Least Developed Countries (LDCs) have very recently been implemented 4G mobile networks for which the overall role out phase is still not complete. In this paper, we investigate how feasible it is for LDCs to emphasize on a possible deployment of 5G networks at the moment. At first, we take a holistic approach to show the major technical challenges LDCs are likely to face while deploying the 5G mobile networks. Then we argue that various security aspects of 5G networks are an ongoing issue and LDCs are not technologically competent to handle many security glitches of 5G networks. At the same time, we show that most of the use cases of 5G networks are not applicable in the context of many LDCs (at least at the present time). Finally, this paper concludes that the start of the 5G network deployment in LDCs would take much longer time than expected.展开更多
Objectives: To challenge the expiry dates of low concentration high purity mycotoxins standards. Literature Review: Aflatoxins (AFs) and Ochratoxin A (OTA) are persistent mycotoxins with adverse effects on humans. Myc...Objectives: To challenge the expiry dates of low concentration high purity mycotoxins standards. Literature Review: Aflatoxins (AFs) and Ochratoxin A (OTA) are persistent mycotoxins with adverse effects on humans. Mycotoxins standards are purchased to determine mycotoxin concentrations in food and may be stocked in some laboratories beyond expiry dates causing laboratories financial losses. Methods: Certified mycotoxins standards were purchased over the years from the same supplier at times and at other times from two different suppliers for quality control purposes. For AFs, six chromatographic runs for each of the mycotoxins standards were done to compare the difference among these standards having the following expiry dates (2008, 2012, 2013 and 2018). AFs standards purchased/obtained from two different suppliers in 2016 and expiring in 2018 were also compared. For OTA, the difference of concentration obtained between two years (2010 and 2018) was tested. All samples were run on a HPLC equipped with a fluorescence detector. Linearity of calibration curves and the points of lowest detection were determined for AFs components and for OTA from the unexpired mycotoxins standards. Results: At a 0.05 significance level and using non parametric tests, the statistical test revealed a p of 0.166, 0.153, 0.358 and 0.03 for B1, G1, B2 and G2 respectively among years for standards from same supplier and 0.037, 0.109, 0.182 and 0.182 for B1, G1, B2 and G2 respectively for unexpired standards from two different suppliers. For OTA, a p of 0.109 was obtained for standards of different expiry dates purchased from different suppliers. Conclusion: High purity low concentration mycotoxin standards purchased a decade ago (i.e. expired) did not differ from those purchased this current year (still valid). Hence, the expiry date can be renewed reducing the laboratories expenses. Manufacturers are urged to reconsider the expiry dates.展开更多
This study comprehensively reviews the literature to deeply explore the role of computer science and internet technologies in addressing educational inequality and socio-psychological issues,with a particular focus on...This study comprehensively reviews the literature to deeply explore the role of computer science and internet technologies in addressing educational inequality and socio-psychological issues,with a particular focus on applications of 5G,artificial intelligence(AI),and augmented/virtual reality(AR/VR).By analyzing how these technologies are reshaping learning and their potential to ameliorate educational disparities,the study reveals challenges present in ensuring educational equity.The research methodology includes exhaustive reviews of applications of AI and machine learning,the Internet of Things and wearable technologies integration,big data analytics and data mining,and the effects of online platforms and social media on socio-psychological issues.Besides,the study discusses applications of these technologies in educational inequality and socio-psychological problem-solving through the lens of 5G,AI,and AR/VR,while also delineating challenges faced by these emerging technologies and future outlooks.The study finds that while computer science and internet technologies hold promise to bridge academic divides and address socio-psychological problems,the complexity of technology access and infrastructure,lack of digital literacy and skills,and critical ethical and privacy issues can impact widespread adoption and efficacy.Overall,the study provides a novel perspective to understand the potential of computer science and internet technologies in ameliorating educational inequality and socio-psychological issues,while pointing to new directions for future research.It also emphasizes the importance of cooperation among educational institutions,technology vendors,policymakers and researchers,and establishing comprehensive ethical guidelines and regulations to ensure the responsible use of these technologies.展开更多
Terahertz(THz)communications have been widely envisioned as a promising enabler to provide adequate bandwidth and achieve ultra-high data rates for sixth generation(6G)wireless networks.In order to mitigate blockage v...Terahertz(THz)communications have been widely envisioned as a promising enabler to provide adequate bandwidth and achieve ultra-high data rates for sixth generation(6G)wireless networks.In order to mitigate blockage vulnerability caused by serious propagation attenuation and poor diffraction of THz waves,an intelligent reflecting surface(IRS),which manipulates the propagation of incident electromagnetic waves in a programmable manner by adjusting the phase shifts of passive reflecting elements,is proposed to create smart radio environments,improve spectrum efficiency and enhance coverage capability.Firstly,some prospective application scenarios driven by the IRS empowered THz communications are introduced,including wireless mobile communications,secure communications,unmanned aerial vehicle(UAV)scenario,mobile edge computing(MEC)scenario and THz localization scenario.Then,we discuss the enabling technologies employed by the IRS empowered THz system,involving hardware design,channel estimation,capacity optimization,beam control,resource allocation and robustness design.Moreover,the arising challenges and open problems encountered in the future IRS empowered THz communications are also highlighted.Concretely,these emerging problems possibly originate from channel modeling,new material exploration,experimental IRS testbeds and intensive deployment.Ultimately,the combination of THz communications and IRS is capable of accelerating the development of 6G wireless networks.展开更多
Under the background of counter economic globalization,the Group of Twenty(G20)has become the primary platform for the east and west powers to seek consultation and dialogue.And the coordination mechanism of the new g...Under the background of counter economic globalization,the Group of Twenty(G20)has become the primary platform for the east and west powers to seek consultation and dialogue.And the coordination mechanism of the new global powers has come into being slowly.As a multilateral regional bank,the BRICsBank takes the interests of developing countries as the leading factor.Based on international economic cooperation ground,it will broaden the South-South cooperation to create more convenient conditions for foreign direct investment,as well as bilateral and multilateral financial cooperation.From new power coordination perspective,with global economy governance structure transformation as the starting point,this research accurately defines the concept of coordination mechanism,systematically analyzes the evolution of global economic governance structure,intensively interprets the current characteristics of big power coordination mode in global economic governance structure,and objective assesses trends of global political and economic pattern.It is of important policy reference implications for the BRICS member countries to effectively promote the BRICs Bank institutionalization and global governance of new power coordination nature.展开更多
With the exponential growth of the data traffic in wireless communication systems, terahertz(THz) frequency band is envisioned as a promising candidate to support ultra-broadband for future beyond fifth generation(5G)...With the exponential growth of the data traffic in wireless communication systems, terahertz(THz) frequency band is envisioned as a promising candidate to support ultra-broadband for future beyond fifth generation(5G), bridging the gap between millimeter wave(mmWave) and optical frequency ranges. The purpose of this paper is to provide a comprehensive literature review on the development towards THz communications and presents some key technologies faced in THz wireless communication systems. Firstly, despite the substantial hardware problems that have to be developed in terms of the THz solid state superheterodyne receiver, high speed THz modulators and THz antennas, the practical THz channel model and the efficient THz beamforming are also described to compensate for the severe path attenuation. Moreover, two different kinds of lab-level THz communication systems are introduced minutely, named a solid state THz communication system and a spatial direct modulation THz communication system, respectively. The solid state THz system converts intermediate frequency(IF) modulated signal to THz frequency while the direct modulation THz system allows the high power THz sources to input for approving the relatively long distance communications. Finally, we discuss several potential application scenarios as well as some vital technical challenges that will be encountered in the future THz communications.展开更多
The year of 2014 saw the beginning of China's LTE,which marks that China has become one of the major engines for the global LTE development.China dazzled in the construction of LTE networks,subscribers,and industr...The year of 2014 saw the beginning of China's LTE,which marks that China has become one of the major engines for the global LTE development.China dazzled in the construction of LTE networks,subscribers,and industry chain.However,the policy formulated around TD-LTE also put China in predicament and brought it many challenges.With this article,we are going to put China's market for mobile broadband networks into perspective,focusing on the development of China's LTE market,challenges that encountered,and the research in this area in the years to come.Besides,in regards to the problems that already appeared,we will,from policy-making,industry-level,and technological points of view,offer our suggestions on how China should do to make this market robust.展开更多
文摘Growing client population, ever-increasing service demand, and complexity of services are the driving factors for the mobile operators for a paradigm shift in their core technology and radio access networks. 5G mobile network is the result of this paradigm shift and currently under deployment in many developed countries such as United States, United Kingdom, South Korea, Japan, and China—to name a few. However, most of the Least Developed Countries (LDCs) have very recently been implemented 4G mobile networks for which the overall role out phase is still not complete. In this paper, we investigate how feasible it is for LDCs to emphasize on a possible deployment of 5G networks at the moment. At first, we take a holistic approach to show the major technical challenges LDCs are likely to face while deploying the 5G mobile networks. Then we argue that various security aspects of 5G networks are an ongoing issue and LDCs are not technologically competent to handle many security glitches of 5G networks. At the same time, we show that most of the use cases of 5G networks are not applicable in the context of many LDCs (at least at the present time). Finally, this paper concludes that the start of the 5G network deployment in LDCs would take much longer time than expected.
文摘Objectives: To challenge the expiry dates of low concentration high purity mycotoxins standards. Literature Review: Aflatoxins (AFs) and Ochratoxin A (OTA) are persistent mycotoxins with adverse effects on humans. Mycotoxins standards are purchased to determine mycotoxin concentrations in food and may be stocked in some laboratories beyond expiry dates causing laboratories financial losses. Methods: Certified mycotoxins standards were purchased over the years from the same supplier at times and at other times from two different suppliers for quality control purposes. For AFs, six chromatographic runs for each of the mycotoxins standards were done to compare the difference among these standards having the following expiry dates (2008, 2012, 2013 and 2018). AFs standards purchased/obtained from two different suppliers in 2016 and expiring in 2018 were also compared. For OTA, the difference of concentration obtained between two years (2010 and 2018) was tested. All samples were run on a HPLC equipped with a fluorescence detector. Linearity of calibration curves and the points of lowest detection were determined for AFs components and for OTA from the unexpired mycotoxins standards. Results: At a 0.05 significance level and using non parametric tests, the statistical test revealed a p of 0.166, 0.153, 0.358 and 0.03 for B1, G1, B2 and G2 respectively among years for standards from same supplier and 0.037, 0.109, 0.182 and 0.182 for B1, G1, B2 and G2 respectively for unexpired standards from two different suppliers. For OTA, a p of 0.109 was obtained for standards of different expiry dates purchased from different suppliers. Conclusion: High purity low concentration mycotoxin standards purchased a decade ago (i.e. expired) did not differ from those purchased this current year (still valid). Hence, the expiry date can be renewed reducing the laboratories expenses. Manufacturers are urged to reconsider the expiry dates.
文摘This study comprehensively reviews the literature to deeply explore the role of computer science and internet technologies in addressing educational inequality and socio-psychological issues,with a particular focus on applications of 5G,artificial intelligence(AI),and augmented/virtual reality(AR/VR).By analyzing how these technologies are reshaping learning and their potential to ameliorate educational disparities,the study reveals challenges present in ensuring educational equity.The research methodology includes exhaustive reviews of applications of AI and machine learning,the Internet of Things and wearable technologies integration,big data analytics and data mining,and the effects of online platforms and social media on socio-psychological issues.Besides,the study discusses applications of these technologies in educational inequality and socio-psychological problem-solving through the lens of 5G,AI,and AR/VR,while also delineating challenges faced by these emerging technologies and future outlooks.The study finds that while computer science and internet technologies hold promise to bridge academic divides and address socio-psychological problems,the complexity of technology access and infrastructure,lack of digital literacy and skills,and critical ethical and privacy issues can impact widespread adoption and efficacy.Overall,the study provides a novel perspective to understand the potential of computer science and internet technologies in ameliorating educational inequality and socio-psychological issues,while pointing to new directions for future research.It also emphasizes the importance of cooperation among educational institutions,technology vendors,policymakers and researchers,and establishing comprehensive ethical guidelines and regulations to ensure the responsible use of these technologies.
基金supported by the National Key Research and Development Project of China under Grant 2018YFB1801500supported in part by The National Natural Science Foundation of China under Grant 6162780166 and Grant 61831012.
文摘Terahertz(THz)communications have been widely envisioned as a promising enabler to provide adequate bandwidth and achieve ultra-high data rates for sixth generation(6G)wireless networks.In order to mitigate blockage vulnerability caused by serious propagation attenuation and poor diffraction of THz waves,an intelligent reflecting surface(IRS),which manipulates the propagation of incident electromagnetic waves in a programmable manner by adjusting the phase shifts of passive reflecting elements,is proposed to create smart radio environments,improve spectrum efficiency and enhance coverage capability.Firstly,some prospective application scenarios driven by the IRS empowered THz communications are introduced,including wireless mobile communications,secure communications,unmanned aerial vehicle(UAV)scenario,mobile edge computing(MEC)scenario and THz localization scenario.Then,we discuss the enabling technologies employed by the IRS empowered THz system,involving hardware design,channel estimation,capacity optimization,beam control,resource allocation and robustness design.Moreover,the arising challenges and open problems encountered in the future IRS empowered THz communications are also highlighted.Concretely,these emerging problems possibly originate from channel modeling,new material exploration,experimental IRS testbeds and intensive deployment.Ultimately,the combination of THz communications and IRS is capable of accelerating the development of 6G wireless networks.
文摘Under the background of counter economic globalization,the Group of Twenty(G20)has become the primary platform for the east and west powers to seek consultation and dialogue.And the coordination mechanism of the new global powers has come into being slowly.As a multilateral regional bank,the BRICsBank takes the interests of developing countries as the leading factor.Based on international economic cooperation ground,it will broaden the South-South cooperation to create more convenient conditions for foreign direct investment,as well as bilateral and multilateral financial cooperation.From new power coordination perspective,with global economy governance structure transformation as the starting point,this research accurately defines the concept of coordination mechanism,systematically analyzes the evolution of global economic governance structure,intensively interprets the current characteristics of big power coordination mode in global economic governance structure,and objective assesses trends of global political and economic pattern.It is of important policy reference implications for the BRICS member countries to effectively promote the BRICs Bank institutionalization and global governance of new power coordination nature.
基金supported by the National High Technology Research and Development Program of China (863 program) of China under Grant No.2011AA010200 supported by the National Natural Science Foundation of China (NSFC) under Grant No.61771116 and No.91738102
文摘With the exponential growth of the data traffic in wireless communication systems, terahertz(THz) frequency band is envisioned as a promising candidate to support ultra-broadband for future beyond fifth generation(5G), bridging the gap between millimeter wave(mmWave) and optical frequency ranges. The purpose of this paper is to provide a comprehensive literature review on the development towards THz communications and presents some key technologies faced in THz wireless communication systems. Firstly, despite the substantial hardware problems that have to be developed in terms of the THz solid state superheterodyne receiver, high speed THz modulators and THz antennas, the practical THz channel model and the efficient THz beamforming are also described to compensate for the severe path attenuation. Moreover, two different kinds of lab-level THz communication systems are introduced minutely, named a solid state THz communication system and a spatial direct modulation THz communication system, respectively. The solid state THz system converts intermediate frequency(IF) modulated signal to THz frequency while the direct modulation THz system allows the high power THz sources to input for approving the relatively long distance communications. Finally, we discuss several potential application scenarios as well as some vital technical challenges that will be encountered in the future THz communications.
文摘The year of 2014 saw the beginning of China's LTE,which marks that China has become one of the major engines for the global LTE development.China dazzled in the construction of LTE networks,subscribers,and industry chain.However,the policy formulated around TD-LTE also put China in predicament and brought it many challenges.With this article,we are going to put China's market for mobile broadband networks into perspective,focusing on the development of China's LTE market,challenges that encountered,and the research in this area in the years to come.Besides,in regards to the problems that already appeared,we will,from policy-making,industry-level,and technological points of view,offer our suggestions on how China should do to make this market robust.
