Vegetation plays an important role in the environmental transport behavior of organic pollutants,however,the different roles of crops and natural vegetation have been ignored in most previous studies.In this study,we ...Vegetation plays an important role in the environmental transport behavior of organic pollutants,however,the different roles of crops and natural vegetation have been ignored in most previous studies.In this study,we developed the BETR-Urban-Rural-Veg model to quantitatively evaluate the influences of both natural vegetation and crops on the multimedia transport processes of Phenanthrene(PHE)and Benzo(a)pyrene(BaP)in mainland of China.The geographic distribution of polycyclic aromatic hydrocarbon(PAH)emissions and concentrations were consistent,displaying higher levels in northern China while lower levels in southern China.Under seasonal simulations,for both natural vegetation and crops,PAH concentrations in winter and spring were 1.5 to 27-fold higher than in summer and autumn,especially for PHE.Owing to the higher leaf area index(LAI)of natural vegetation and harvesting of crops,the filter and sequestration effect of natural vegetation was stronger than crops,while the seasonal changes of PAH concentrations in crops were more significant than natural vegetation.Temperature,precipitation rates and LAI might have important influences on seasonal concentrations and overall persistence of PAHs.PHE was more sensitive to the impacts of seasonal environmental parameters.Under different landscape scenarios,average annual PAH concentrations in natural vegetation were always a little higher than those in crops,and the overall persistence of BaP was greatly affected increasing by 15.15%-16.47%.This improved model provides a useful tool for environmental management.The results of this study are expected to support land use plans and decision-making in China's mainland.展开更多
With the rapid development of Internet technology and the rapid increase of multimedia information, people put forward higher requirements for the security, reliability, stability and efficiency of multimedia file tra...With the rapid development of Internet technology and the rapid increase of multimedia information, people put forward higher requirements for the security, reliability, stability and efficiency of multimedia file transmission. As far as the current network situation is concerned, there are various problems in network security, so how to ensure the safe transmission of files is a very important research topic. In order to improve the security effect of database information, we should also do a good job of classification and archiving storage. Multimedia files must be heavily compressed so that they can be efficiently transmitted over traditional data communication networks. The rapid development of computer networks has made people's lives more and more convenient. In the process of using computer networks, it is necessary to actively strengthen the security control of file transmission on computer networks. Take appropriate measures to avoid network file transmission security risks.展开更多
This report gives a view of a computer multimedia book of mechanical drawing. This electronic book is developed under Windows and Chinese Star to form an integrated system on a CD-ROM. In the electronic book, graphics...This report gives a view of a computer multimedia book of mechanical drawing. This electronic book is developed under Windows and Chinese Star to form an integrated system on a CD-ROM. In the electronic book, graphics, images, 3D animation, audio, video and text techniques of computer multimedia are applied. The techniques, methods, contents and purpose of developing this system are introduced.展开更多
Through the mapping from UMQL （ unified multimedia query language） conditional expressions to UMQA （unified multimedia query algebra） query operations, a translation algorithm from a UMQL query to a UMQA query pla...Through the mapping from UMQL （ unified multimedia query language） conditional expressions to UMQA （unified multimedia query algebra） query operations, a translation algorithm from a UMQL query to a UMQA query plan is put forward, which can generate an equivalent UMQA internal query plan for any UMQL query. Then, to improve the execution costs of UMQA query plans effectively, equivalent UMQA translation formulae and general optimization strategies are studied, and an optimization algorithm for UMQA internal query plans is presented. This algorithm uses equivalent UMQA translation formulae to optimize query plans, and makes the optimized query plans accord with the optimization strategies as much as possible. Finally, the logic implementation methods of UMQA plans, i.e., logic implementation methods of UMQA operators, are discussed to obtain useful target data from a muifirnedia database. All of these algorithms are implemented in a UMQL prototype system. Application results show that these query processing techniques are feasible and applicable.展开更多
In the Engine CAD application system engineering database management system (ECAD-EDBMS) is the kernel. ECAD-EDBMS can manage and process the multimedia such as graphics, data, text, sound, image and video. It provide...In the Engine CAD application system engineering database management system (ECAD-EDBMS) is the kernel. ECAD-EDBMS can manage and process the multimedia such as graphics, data, text, sound, image and video. It provides the integrated environment and more functions for many subsystems of ECAD and engine designers. So it improves the design efficiency.展开更多
This thesis aims at providing an overview of the recent developments and reforms in the college English education. With the employment of multi-media teaching facilities, intercultural competence, i.e., the flexible a...This thesis aims at providing an overview of the recent developments and reforms in the college English education. With the employment of multi-media teaching facilities, intercultural competence, i.e., the flexible adoption of the systems of value outlook and behavior mode of the target language, has indisputably been integrated into the second language learning and teaching curriculum. This thesis compares and analyzes the nature and composition of cultural cognition.展开更多
Based on the constructivism, using the College English（new edition） CD-ROMs for classroom teaching as main media, this paper explores the feasibility of the classroom teaching mode of appropriate combination of trad...Based on the constructivism, using the College English（new edition） CD-ROMs for classroom teaching as main media, this paper explores the feasibility of the classroom teaching mode of appropriate combination of traditional methods with the multimedia overhead projector. The new teaching mode proves to be successful in that it has greatly improved the students＇ ability to use English in an all-round way and has obvious advantages over the only traditional method.展开更多
Based on critical thinking of the relevant literature,the study has been carried out to investigate to what extent Whole Language Approach contributes to better results and motivates students to acquire the English la...Based on critical thinking of the relevant literature,the study has been carried out to investigate to what extent Whole Language Approach contributes to better results and motivates students to acquire the English language faster and more naturally in the multimedia language lab.A tentative model of whole language teaching comes into view,and an eighteen-month experimental project is designed and implemented in Hebei University,China.Research evaluation in both the qualitative and quantitative approaches is conducted and analyzed to ensure validity and reliability of the research.展开更多
With the development of social economy,the multimedia and network teaching is more and more important in college English teaching,especially in vocational college.It can not only help students to give full play to the...With the development of social economy,the multimedia and network teaching is more and more important in college English teaching,especially in vocational college.It can not only help students to give full play to their collective consciousness and make our English course be full of vitality,but also make the amount of information in class redoubled.For the multimedia and network teaching,there're some problems in English teaching.So the multimedia and network teaching has both necessities and problems.展开更多
For the current foreign language teaching, using multimedia technology has become a necessity in information age. The modernization of computer has paved a new way of deepening teaching reform and improving teaching e...For the current foreign language teaching, using multimedia technology has become a necessity in information age. The modernization of computer has paved a new way of deepening teaching reform and improving teaching efficiency and quality. With the computer technology applied in education, language teachers have witnessed dramatic changes in the ways that languages are taught. Multimedia technology applied in English teaching has been considered to be a more effective medium, which represents an inevitable trend of applied linguistics.展开更多
Advanced English is a key course for English majors in advanced stage.This paper first proposes the problems in tradi tional advanced English teaching.Then it explains the theoretical basis and finally the paper state...Advanced English is a key course for English majors in advanced stage.This paper first proposes the problems in tradi tional advanced English teaching.Then it explains the theoretical basis and finally the paper states advantages of multimedia teach ing in Advanced English.展开更多
First, the date palm kernel is used to produce granular activated carbon （GAC） by a physiochemical activation process. The process involves six steps： washing, drying, crushing, sieving, carbonization, and activati...First, the date palm kernel is used to produce granular activated carbon （GAC） by a physiochemical activation process. The process involves six steps： washing, drying, crushing, sieving, carbonization, and activation. Secondly, the ability of the produced GAC to remove pollutants is examined through batch experiments of residual chlorine adsorption whereas the equilibrium isotherm experimental data are tested for the Langmuir and Freundlich isotherms equations. Thirdly, the experimental and theoretical study of dynamic adsorption process and the effect of major operating parameters on dynamic adsorption are investigated. The results show that the Langmuir isotherm gives the best fitting to experimental data, which indicates that the residual chlorine adsorption can be characterized by mono layer adsorption behavior. The produced GAC has a great potential as an adsorbent for residual chlorine in water systems and it can compete favorably with the conventional adsorbents. The Thomas extended model with combined mass transfer resistances is used for verifying the experimental results and the results show that the proposed model coincides well with the experimental data of the dynamic adsorption process.展开更多
Nowadays,healthcare applications necessitate maximum volume of medical data to be fed to help the physicians,academicians,pathologists,doctors and other healthcare professionals.Advancements in the domain of Wireless ...Nowadays,healthcare applications necessitate maximum volume of medical data to be fed to help the physicians,academicians,pathologists,doctors and other healthcare professionals.Advancements in the domain of Wireless Sensor Networks(WSN)andMultimediaWireless Sensor Networks(MWSN)are tremendous.M-WMSN is an advanced form of conventional Wireless Sensor Networks(WSN)to networks that use multimedia devices.When compared with traditional WSN,the quantity of data transmission in M-WMSN is significantly high due to the presence of multimedia content.Hence,clustering techniques are deployed to achieve low amount of energy utilization.The current research work aims at introducing a new Density Based Clustering(DBC)technique to achieve energy efficiency inWMSN.The DBC technique is mainly employed for data collection in healthcare environment which primarily depends on three input parameters namely remaining energy level,distance,and node centrality.In addition,two static data collector points called Super Cluster Head(SCH)are placed,which collects the data from normal CHs and forwards it to the Base Station(BS)directly.SCH supports multi-hop data transmission that assists in effectively balancing the available energy.Adetailed simulation analysiswas conducted to showcase the superior performance of DBC technique and the results were examined under diverse aspects.The simulation outcomes concluded that the proposed DBC technique improved the network lifetime to a maximum of 16,500 rounds,which is significantly higher compared to existing methods.展开更多
According to large coverage of satellites, there are various channel states in a satellite broadcasting network. In order to introduce an efficient rateless transmission method to satellite multimedia broadcasting/mul...According to large coverage of satellites, there are various channel states in a satellite broadcasting network. In order to introduce an efficient rateless transmission method to satellite multimedia broadcasting/multicast services with finite-length packets, a cross-layer packet transmission method is proposed with Luby transform （LT） codes for efficiency in the network layer and low density parity check （LDPC） codes for reliability in the physical layer jointly. The codewords generated from an LT encoder are divided into finite-length packets, which are encoded by an LDPC encoder subsequently. Based on noise and fading effects of satellite channels, the LT packets received from an LDPC decoder either have no error or are marked as erased, which can be mod- eled as a binary erasure channels （BECs）. By theoretical analysis on LT parameters and LDPC parameters, the relationships between LDPC code rates in the physical layer and LT codes word lengths in the network layer are investigated. With tradeoffs between the LT codes word lengths and the LDPC code rates, optimized cross-layer solutions are achieved with a binary search algorithm. Verified by simulations, the proposed solution for cross-layer parameters design can provide the best transmission mode according to satellite states, so as to improve throughput performance for satellite multimedia transmission.展开更多
A geographical information system (GIS) is used to capture, store, retrieve, analyzed and display the spatial (locationally defined) data. In contrast to traditional GIS, multimedia GIS is not only able to collect, an...A geographical information system (GIS) is used to capture, store, retrieve, analyzed and display the spatial (locationally defined) data. In contrast to traditional GIS, multimedia GIS is not only able to collect, analyze and store the data in traditional formats i.e. text, images (pictures) and graphs but also audio (sound), animations and video (moving pictures) as well. In this paper the advantages of multimedia GIS over traditional GIS are explained. Multimedia GIS is fully capable of providing services to both technical and non technical users and users of multimedia GIS can retain more knowledge than users of traditional GIS. It can be applied to various fields such as tourism, environment, education etc. Some implementation issues such as data updating, information retrieval and data compression etc. are also addressed. Finally, future development of MMGIS (using new multimedia technologies such as Virtual Reality and Virtual Reality Modeling Language) is discussed.展开更多
Emission intensity and climate change control the transport flux and fate of persistent organic pollutants(POPs)inmultiple environmental compartments.This study applied amultimedia model(BETR model)to explore alternat...Emission intensity and climate change control the transport flux and fate of persistent organic pollutants(POPs)inmultiple environmental compartments.This study applied amultimedia model(BETR model)to explore alternations in the spatio-temporal trends of concentrations and transport flux of benzopyrene(BaP),phenanthrene(Phe),perfluorooctane sulfonates(PFOS)and polychlorinated biphenyls(PCBs)in the Chaohu watershed,located in the lower reaches of the Yangtze River,China in response to changes in source emissions and climate.The potential historic and future risks of these pollutants also were assessed.The results suggest that current trends in concentrations and transport were similar to that of their emissions between 2005 and 2018.During the next 100 years,temporal trends and spatial patterns were not predicted to change significantly,which is consistent with climate change.Based on sensitivity and correlation analyses,climate change had significant effects on multi-media concentrations and transport fluxes of BaP,Phe,PFOS and PCBs,and rainfall intensity was the predominant controlling factor.Risk quotients(RQs)of BaP and Phe-in soil increased from 0.42 to 0.95 and 0.06 to 0.35,respectively,from 2005 to 2090,indicating potential risks.The RQs of the other examined contaminants exhibited little potential risk in soil,water,or sediment.Based on spatial patterns,it was inferred that the ecosystem around Lake Chaohu is the most at risk.The study provides insights needed for local pollution control of POPs in the Chaohu watershed.In addition,the developed approach can be applied to other watersheds world-wide.展开更多
Providing highly efficient underwater transmission of mass multimedia data is challenging due to the particularities of the underwater environment. Although there are many schemes proposed to optimize the underwater a...Providing highly efficient underwater transmission of mass multimedia data is challenging due to the particularities of the underwater environment. Although there are many schemes proposed to optimize the underwater acoustic network communication protocols, from physical layer, data link layer, network layer to transport layer, the existing routing protocols for underwater wireless sensor network(UWSN) still cannot well deal with the problems in transmitting multimedia data because of the difficulties involved in high energy consumption, low transmission reliability or high transmission delay. It prevents us from applying underwater multimedia data to real-time monitoring of marine environment in practical application, especially in emergency search, rescue operation and military field. Therefore, the inefficient transmission of marine multimedia data has become a serious problem that needs to be solved urgently. In this paper, A Layered Load Balance Routing Protocol(L2-LBMT) is proposed for underwater multimedia data transmission. In L2-LBMT, we use layered and load-balance Ad Hoc Network to transmit data, and adopt segmented data reliable transfer(SDRT) protocol to improve the data transport reliability. And a 3-node variant of tornado(3-VT) code is also combined with the Ad Hoc Network to transmit little emergency data more quickly. The simulation results show that the proposed protocol can balance energy consumption of each node, effectively prolong the network lifetime and reduce transmission delay of marine multimedia data.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42107420,U23A20157,and U1910207)Shanxi Province Science Foundation for Young Scholars(No.20210302124363).
文摘Vegetation plays an important role in the environmental transport behavior of organic pollutants,however,the different roles of crops and natural vegetation have been ignored in most previous studies.In this study,we developed the BETR-Urban-Rural-Veg model to quantitatively evaluate the influences of both natural vegetation and crops on the multimedia transport processes of Phenanthrene(PHE)and Benzo(a)pyrene(BaP)in mainland of China.The geographic distribution of polycyclic aromatic hydrocarbon(PAH)emissions and concentrations were consistent,displaying higher levels in northern China while lower levels in southern China.Under seasonal simulations,for both natural vegetation and crops,PAH concentrations in winter and spring were 1.5 to 27-fold higher than in summer and autumn,especially for PHE.Owing to the higher leaf area index(LAI)of natural vegetation and harvesting of crops,the filter and sequestration effect of natural vegetation was stronger than crops,while the seasonal changes of PAH concentrations in crops were more significant than natural vegetation.Temperature,precipitation rates and LAI might have important influences on seasonal concentrations and overall persistence of PAHs.PHE was more sensitive to the impacts of seasonal environmental parameters.Under different landscape scenarios,average annual PAH concentrations in natural vegetation were always a little higher than those in crops,and the overall persistence of BaP was greatly affected increasing by 15.15%-16.47%.This improved model provides a useful tool for environmental management.The results of this study are expected to support land use plans and decision-making in China's mainland.
文摘With the rapid development of Internet technology and the rapid increase of multimedia information, people put forward higher requirements for the security, reliability, stability and efficiency of multimedia file transmission. As far as the current network situation is concerned, there are various problems in network security, so how to ensure the safe transmission of files is a very important research topic. In order to improve the security effect of database information, we should also do a good job of classification and archiving storage. Multimedia files must be heavily compressed so that they can be efficiently transmitted over traditional data communication networks. The rapid development of computer networks has made people's lives more and more convenient. In the process of using computer networks, it is necessary to actively strengthen the security control of file transmission on computer networks. Take appropriate measures to avoid network file transmission security risks.
文摘This report gives a view of a computer multimedia book of mechanical drawing. This electronic book is developed under Windows and Chinese Star to form an integrated system on a CD-ROM. In the electronic book, graphics, images, 3D animation, audio, video and text techniques of computer multimedia are applied. The techniques, methods, contents and purpose of developing this system are introduced.
基金The National High Technology Research and Development Program of China(863 Program) (No.2006AA01Z430)
文摘Through the mapping from UMQL （ unified multimedia query language） conditional expressions to UMQA （unified multimedia query algebra） query operations, a translation algorithm from a UMQL query to a UMQA query plan is put forward, which can generate an equivalent UMQA internal query plan for any UMQL query. Then, to improve the execution costs of UMQA query plans effectively, equivalent UMQA translation formulae and general optimization strategies are studied, and an optimization algorithm for UMQA internal query plans is presented. This algorithm uses equivalent UMQA translation formulae to optimize query plans, and makes the optimized query plans accord with the optimization strategies as much as possible. Finally, the logic implementation methods of UMQA plans, i.e., logic implementation methods of UMQA operators, are discussed to obtain useful target data from a muifirnedia database. All of these algorithms are implemented in a UMQL prototype system. Application results show that these query processing techniques are feasible and applicable.
文摘In the Engine CAD application system engineering database management system (ECAD-EDBMS) is the kernel. ECAD-EDBMS can manage and process the multimedia such as graphics, data, text, sound, image and video. It provides the integrated environment and more functions for many subsystems of ECAD and engine designers. So it improves the design efficiency.
文摘This thesis aims at providing an overview of the recent developments and reforms in the college English education. With the employment of multi-media teaching facilities, intercultural competence, i.e., the flexible adoption of the systems of value outlook and behavior mode of the target language, has indisputably been integrated into the second language learning and teaching curriculum. This thesis compares and analyzes the nature and composition of cultural cognition.
文摘Based on the constructivism, using the College English（new edition） CD-ROMs for classroom teaching as main media, this paper explores the feasibility of the classroom teaching mode of appropriate combination of traditional methods with the multimedia overhead projector. The new teaching mode proves to be successful in that it has greatly improved the students＇ ability to use English in an all-round way and has obvious advantages over the only traditional method.
文摘Based on critical thinking of the relevant literature,the study has been carried out to investigate to what extent Whole Language Approach contributes to better results and motivates students to acquire the English language faster and more naturally in the multimedia language lab.A tentative model of whole language teaching comes into view,and an eighteen-month experimental project is designed and implemented in Hebei University,China.Research evaluation in both the qualitative and quantitative approaches is conducted and analyzed to ensure validity and reliability of the research.
文摘With the development of social economy,the multimedia and network teaching is more and more important in college English teaching,especially in vocational college.It can not only help students to give full play to their collective consciousness and make our English course be full of vitality,but also make the amount of information in class redoubled.For the multimedia and network teaching,there're some problems in English teaching.So the multimedia and network teaching has both necessities and problems.
文摘For the current foreign language teaching, using multimedia technology has become a necessity in information age. The modernization of computer has paved a new way of deepening teaching reform and improving teaching efficiency and quality. With the computer technology applied in education, language teachers have witnessed dramatic changes in the ways that languages are taught. Multimedia technology applied in English teaching has been considered to be a more effective medium, which represents an inevitable trend of applied linguistics.
文摘Advanced English is a key course for English majors in advanced stage.This paper first proposes the problems in tradi tional advanced English teaching.Then it explains the theoretical basis and finally the paper states advantages of multimedia teach ing in Advanced English.
基金The National Natural Science Foundation of China(No. 51078074)
文摘First, the date palm kernel is used to produce granular activated carbon （GAC） by a physiochemical activation process. The process involves six steps： washing, drying, crushing, sieving, carbonization, and activation. Secondly, the ability of the produced GAC to remove pollutants is examined through batch experiments of residual chlorine adsorption whereas the equilibrium isotherm experimental data are tested for the Langmuir and Freundlich isotherms equations. Thirdly, the experimental and theoretical study of dynamic adsorption process and the effect of major operating parameters on dynamic adsorption are investigated. The results show that the Langmuir isotherm gives the best fitting to experimental data, which indicates that the residual chlorine adsorption can be characterized by mono layer adsorption behavior. The produced GAC has a great potential as an adsorbent for residual chlorine in water systems and it can compete favorably with the conventional adsorbents. The Thomas extended model with combined mass transfer resistances is used for verifying the experimental results and the results show that the proposed model coincides well with the experimental data of the dynamic adsorption process.
文摘Nowadays,healthcare applications necessitate maximum volume of medical data to be fed to help the physicians,academicians,pathologists,doctors and other healthcare professionals.Advancements in the domain of Wireless Sensor Networks(WSN)andMultimediaWireless Sensor Networks(MWSN)are tremendous.M-WMSN is an advanced form of conventional Wireless Sensor Networks(WSN)to networks that use multimedia devices.When compared with traditional WSN,the quantity of data transmission in M-WMSN is significantly high due to the presence of multimedia content.Hence,clustering techniques are deployed to achieve low amount of energy utilization.The current research work aims at introducing a new Density Based Clustering(DBC)technique to achieve energy efficiency inWMSN.The DBC technique is mainly employed for data collection in healthcare environment which primarily depends on three input parameters namely remaining energy level,distance,and node centrality.In addition,two static data collector points called Super Cluster Head(SCH)are placed,which collects the data from normal CHs and forwards it to the Base Station(BS)directly.SCH supports multi-hop data transmission that assists in effectively balancing the available energy.Adetailed simulation analysiswas conducted to showcase the superior performance of DBC technique and the results were examined under diverse aspects.The simulation outcomes concluded that the proposed DBC technique improved the network lifetime to a maximum of 16,500 rounds,which is significantly higher compared to existing methods.
基金supported by the National Natural Science Foundation of China (No.61101125)
文摘According to large coverage of satellites, there are various channel states in a satellite broadcasting network. In order to introduce an efficient rateless transmission method to satellite multimedia broadcasting/multicast services with finite-length packets, a cross-layer packet transmission method is proposed with Luby transform （LT） codes for efficiency in the network layer and low density parity check （LDPC） codes for reliability in the physical layer jointly. The codewords generated from an LT encoder are divided into finite-length packets, which are encoded by an LDPC encoder subsequently. Based on noise and fading effects of satellite channels, the LT packets received from an LDPC decoder either have no error or are marked as erased, which can be mod- eled as a binary erasure channels （BECs）. By theoretical analysis on LT parameters and LDPC parameters, the relationships between LDPC code rates in the physical layer and LT codes word lengths in the network layer are investigated. With tradeoffs between the LT codes word lengths and the LDPC code rates, optimized cross-layer solutions are achieved with a binary search algorithm. Verified by simulations, the proposed solution for cross-layer parameters design can provide the best transmission mode according to satellite states, so as to improve throughput performance for satellite multimedia transmission.
文摘A geographical information system (GIS) is used to capture, store, retrieve, analyzed and display the spatial (locationally defined) data. In contrast to traditional GIS, multimedia GIS is not only able to collect, analyze and store the data in traditional formats i.e. text, images (pictures) and graphs but also audio (sound), animations and video (moving pictures) as well. In this paper the advantages of multimedia GIS over traditional GIS are explained. Multimedia GIS is fully capable of providing services to both technical and non technical users and users of multimedia GIS can retain more knowledge than users of traditional GIS. It can be applied to various fields such as tourism, environment, education etc. Some implementation issues such as data updating, information retrieval and data compression etc. are also addressed. Finally, future development of MMGIS (using new multimedia technologies such as Virtual Reality and Virtual Reality Modeling Language) is discussed.
基金supported by the National Key Research and Development Program of China(No.2017YFA0605003)the National Natural Science Foundation of China(Nos.51922010,41521003).
文摘Emission intensity and climate change control the transport flux and fate of persistent organic pollutants(POPs)inmultiple environmental compartments.This study applied amultimedia model(BETR model)to explore alternations in the spatio-temporal trends of concentrations and transport flux of benzopyrene(BaP),phenanthrene(Phe),perfluorooctane sulfonates(PFOS)and polychlorinated biphenyls(PCBs)in the Chaohu watershed,located in the lower reaches of the Yangtze River,China in response to changes in source emissions and climate.The potential historic and future risks of these pollutants also were assessed.The results suggest that current trends in concentrations and transport were similar to that of their emissions between 2005 and 2018.During the next 100 years,temporal trends and spatial patterns were not predicted to change significantly,which is consistent with climate change.Based on sensitivity and correlation analyses,climate change had significant effects on multi-media concentrations and transport fluxes of BaP,Phe,PFOS and PCBs,and rainfall intensity was the predominant controlling factor.Risk quotients(RQs)of BaP and Phe-in soil increased from 0.42 to 0.95 and 0.06 to 0.35,respectively,from 2005 to 2090,indicating potential risks.The RQs of the other examined contaminants exhibited little potential risk in soil,water,or sediment.Based on spatial patterns,it was inferred that the ecosystem around Lake Chaohu is the most at risk.The study provides insights needed for local pollution control of POPs in the Chaohu watershed.In addition,the developed approach can be applied to other watersheds world-wide.
基金supported by the National Natural Science Foundation of China (No.61401413)the Digital Home Industry Cluster Oriented Technology Service Innovation Pilot Project in 2015
文摘Providing highly efficient underwater transmission of mass multimedia data is challenging due to the particularities of the underwater environment. Although there are many schemes proposed to optimize the underwater acoustic network communication protocols, from physical layer, data link layer, network layer to transport layer, the existing routing protocols for underwater wireless sensor network(UWSN) still cannot well deal with the problems in transmitting multimedia data because of the difficulties involved in high energy consumption, low transmission reliability or high transmission delay. It prevents us from applying underwater multimedia data to real-time monitoring of marine environment in practical application, especially in emergency search, rescue operation and military field. Therefore, the inefficient transmission of marine multimedia data has become a serious problem that needs to be solved urgently. In this paper, A Layered Load Balance Routing Protocol(L2-LBMT) is proposed for underwater multimedia data transmission. In L2-LBMT, we use layered and load-balance Ad Hoc Network to transmit data, and adopt segmented data reliable transfer(SDRT) protocol to improve the data transport reliability. And a 3-node variant of tornado(3-VT) code is also combined with the Ad Hoc Network to transmit little emergency data more quickly. The simulation results show that the proposed protocol can balance energy consumption of each node, effectively prolong the network lifetime and reduce transmission delay of marine multimedia data.
