In order to design a new kind of mobile database management system (DBMS)more suitable for mobile computing than the existent DBMS, the essence of database systems in mobilecomputing is analyzed. An opinion is introdu...In order to design a new kind of mobile database management system (DBMS)more suitable for mobile computing than the existent DBMS, the essence of database systems in mobilecomputing is analyzed. An opinion is introduced that the mobile database is a kind of dynamicdistributed database, and the concept of virtual servers to translate the clients' mobility to theservers' mobility is proposed. Based on these opinions, a kind of architecture of mobile DBMS, whichis of versatility, is presented. The architecture is composed of a virtual server and a local DBMS,the virtual server is the kernel of the architecture and its functions are described. Eventually,the server kernel of a mobile DBMS prototype is illustrated.展开更多
Modern datacenter servers hosting popular Internet services face significant and multi-facet challenges in performance and power control. The user-perceived performance is the result of a complex interaction of comple...Modern datacenter servers hosting popular Internet services face significant and multi-facet challenges in performance and power control. The user-perceived performance is the result of a complex interaction of complex workloads in a very complex underlying system. Highly dynamic and bursty workloads of Internet services fluctuate over multiple time scales, which has a significant impact on processing and power demands of datacenter servers. High-density servers apply virtualization technology for capacity planning and system manageability. Such virtuMized computer systems are increasingly large and complex. This paper surveys representative approaches to autonomic performance and power control on virtualized servers, which control the quality of service provided by virtualized resources, improve the energy efficiency of the underlying system, and reduce the burden of complex system management from human operators. It then presents three designed self-adaptive resource management techniques based on machine learning and control for percentile-based response time assurance, non-intrusive energy-efficient performance isolation, and joint performance and power guarantee on virtualized servers. The techniques were implemented and evaluated in a testbed of virtualized servers hosting benchmark applications. Finally, two research trends are identified and discussed for sustainable cloud computing in green datacenters.展开更多
<div style="text-align:justify;"> <span style="font-family:Verdana;">Average Bangladeshis spend a significant amount of income on medicine. A reliable and fast online medicine delivery ...<div style="text-align:justify;"> <span style="font-family:Verdana;">Average Bangladeshis spend a significant amount of income on medicine. A reliable and fast online medicine delivery system is not ubiquitous. Most people buy medicine from the local Pharmacies. They need to go to medicine stores to buy the specific medicine prescribed by the specialized doctors. Sometimes all prescribed medicines are not available in local Pharmacies therefore people need to go to other areas to buy the medicines. It is very time consuming and people need to spend money as well for this. In our country, traffic jams are a very big problem. People waste longer time on the road due to traffic jams. Here most of the pharmacies are closed at night time but sometimes in an emergency situation medicine is very essential. In this case an online web based e-commerce medicine delivery system is needed very much. In addition, currently the whole world is suffering due to COVID-19 pandemic. Coronavirus is very contagious which we all know. In this pandemic time it is not risk free to go out to buy medicine from the pharmacies. Due to COVID-19, medicine scarcity is also an important issue. In this situation, an online medicine delivery system can play an important role. By considering the above mentioned facts, a reliable and fast online solution is proposed. This paper presents the development of a web based online medicine delivery system. A reliable, fast, safe and user-friendly online based e-commerce web application has been developed in this paper. Medicine delivery system has also been included with this proposed system. This platform is a dynamic web application built in Hypertext Preprocessor (PHP) based Laravel framework with a powerful back end. It is hosted on a dedicated Virtual Private Server (VPS). This system is lightning fast and optimized very well for searching engines. With the help of the developed platform, drugs will be available at one’s doorstep very fast, safely and reliably. In this system, users can choose a medicine section of their choices and go through all the items that the system provides. Users can then select the desired drug items, add them to cart and then proceed to payment. It has payment integration of Cash on Delivery (COD) systems. After developing the system it has been tested and it works fine. It is a one-stop solution where people can find various medicines including COVID-19 related medicines and other items in this online platform. Besides medicine, here you can also find other health care products like food supplements, birth control products, hair care products, skincare products, beauty products, etc. People can order their required medicines or other medical related available items from online and the delivery support will provide the products door to door for the users. Using this system now users can get their needed medicine without leaving home. They can save money and they do not need to go out in this pandemic situation to buy medicine. In this crucial situation, the online medicine delivery system is very helpful and it will act as a blessing for the people.</span> </div>展开更多
文摘In order to design a new kind of mobile database management system (DBMS)more suitable for mobile computing than the existent DBMS, the essence of database systems in mobilecomputing is analyzed. An opinion is introduced that the mobile database is a kind of dynamicdistributed database, and the concept of virtual servers to translate the clients' mobility to theservers' mobility is proposed. Based on these opinions, a kind of architecture of mobile DBMS, whichis of versatility, is presented. The architecture is composed of a virtual server and a local DBMS,the virtual server is the kernel of the architecture and its functions are described. Eventually,the server kernel of a mobile DBMS prototype is illustrated.
基金supported in part by the National Science Foundation of USA under Grant Nos.CNS-0844983(CAREER Award)and CNS-1217979the National Natural Science Foundation of China under Grant No.61328203
文摘Modern datacenter servers hosting popular Internet services face significant and multi-facet challenges in performance and power control. The user-perceived performance is the result of a complex interaction of complex workloads in a very complex underlying system. Highly dynamic and bursty workloads of Internet services fluctuate over multiple time scales, which has a significant impact on processing and power demands of datacenter servers. High-density servers apply virtualization technology for capacity planning and system manageability. Such virtuMized computer systems are increasingly large and complex. This paper surveys representative approaches to autonomic performance and power control on virtualized servers, which control the quality of service provided by virtualized resources, improve the energy efficiency of the underlying system, and reduce the burden of complex system management from human operators. It then presents three designed self-adaptive resource management techniques based on machine learning and control for percentile-based response time assurance, non-intrusive energy-efficient performance isolation, and joint performance and power guarantee on virtualized servers. The techniques were implemented and evaluated in a testbed of virtualized servers hosting benchmark applications. Finally, two research trends are identified and discussed for sustainable cloud computing in green datacenters.
文摘<div style="text-align:justify;"> <span style="font-family:Verdana;">Average Bangladeshis spend a significant amount of income on medicine. A reliable and fast online medicine delivery system is not ubiquitous. Most people buy medicine from the local Pharmacies. They need to go to medicine stores to buy the specific medicine prescribed by the specialized doctors. Sometimes all prescribed medicines are not available in local Pharmacies therefore people need to go to other areas to buy the medicines. It is very time consuming and people need to spend money as well for this. In our country, traffic jams are a very big problem. People waste longer time on the road due to traffic jams. Here most of the pharmacies are closed at night time but sometimes in an emergency situation medicine is very essential. In this case an online web based e-commerce medicine delivery system is needed very much. In addition, currently the whole world is suffering due to COVID-19 pandemic. Coronavirus is very contagious which we all know. In this pandemic time it is not risk free to go out to buy medicine from the pharmacies. Due to COVID-19, medicine scarcity is also an important issue. In this situation, an online medicine delivery system can play an important role. By considering the above mentioned facts, a reliable and fast online solution is proposed. This paper presents the development of a web based online medicine delivery system. A reliable, fast, safe and user-friendly online based e-commerce web application has been developed in this paper. Medicine delivery system has also been included with this proposed system. This platform is a dynamic web application built in Hypertext Preprocessor (PHP) based Laravel framework with a powerful back end. It is hosted on a dedicated Virtual Private Server (VPS). This system is lightning fast and optimized very well for searching engines. With the help of the developed platform, drugs will be available at one’s doorstep very fast, safely and reliably. In this system, users can choose a medicine section of their choices and go through all the items that the system provides. Users can then select the desired drug items, add them to cart and then proceed to payment. It has payment integration of Cash on Delivery (COD) systems. After developing the system it has been tested and it works fine. It is a one-stop solution where people can find various medicines including COVID-19 related medicines and other items in this online platform. Besides medicine, here you can also find other health care products like food supplements, birth control products, hair care products, skincare products, beauty products, etc. People can order their required medicines or other medical related available items from online and the delivery support will provide the products door to door for the users. Using this system now users can get their needed medicine without leaving home. They can save money and they do not need to go out in this pandemic situation to buy medicine. In this crucial situation, the online medicine delivery system is very helpful and it will act as a blessing for the people.</span> </div>