A new ROMless twiddle factor generator for radix-2 1024-point FFT is proposed.It consists of several simple logic units and each of them synthesizes some data,which will be used to compose the twiddle factors.The powe...A new ROMless twiddle factor generator for radix-2 1024-point FFT is proposed.It consists of several simple logic units and each of them synthesizes some data,which will be used to compose the twiddle factors.The power analysis with Synopsys Power Compiler shows that it consumes about 2mW with TSMC 0.25μm CMOS process at 50MHz.This twiddle factor generator is designed for the low power applications,especially for the mobile communications and other portable devices...展开更多
GIS applications to mobile devices are becoming i nc reasingly popular, utilizing a di-verserange of devices. Many of these devices suffer from serious constraints in three main areas: processor speed, memory space an...GIS applications to mobile devices are becoming i nc reasingly popular, utilizing a di-verserange of devices. Many of these devices suffer from serious constraints in three main areas: processor speed, memory space and screen size. This paper presents a GIS application, called "MacaoMap", that is intended for heavily resource-co nstrained handheld devices. MacaoMap is a tourism-oriented map application of t he Macao territory for PalmOS and Pocket PC personal digital assistants. It was designed to perform satisfactorily on devices with as little as 16 MHz processor speed, and requires only 500 KB available memory for the GIS application and al l GIS data. Memory requirements are kept low through a specially designed data f ormat. The main challenge of satisfactory map drawing speed is addressed through a variety of techniques that were developed for this application. The paper des cribes the application’s data format, outlines the map drawing techniques, and points out the areas for future development.展开更多
The resilient storage outsourcing schemes in mobile cloud computing are analyzed. It is pointed out that the sharing-based scheme （ShS） has vulnerabilities regarding confidentiality and integrity; meanwhile, the cod...The resilient storage outsourcing schemes in mobile cloud computing are analyzed. It is pointed out that the sharing-based scheme （ShS） has vulnerabilities regarding confidentiality and integrity; meanwhile, the coding-based scheme （COS） and the encryption-based scheme （EnS） have vulnerabilities on integrity. The corresponding attacks on these vulnerabilities are given. Then, the improved protocols such as the secure sharing-based protocol （SShP）, the secure coding-based protocol （SCoP） and the secure encryption- based protocol （SEnP）, are proposed to overcome these vulnerabilities. The core elements are protected through public key encryptions and digital signatures. Security analyses show that the confidentiality and the integrity of the improved protocols are guaranteed. Meanwhile, the improved protocols can keep the frame of the former schemes and have higher security. The simulation results illustrate that compared with the existing protocols, the communication overhead of the improved protocols is not significantly increased.展开更多
A mobile transmission strategy, PMPatching (Proxy-based Mobile Patching) transmission strat-egy is proposed, it applies to the proxy-based mobile streaming media system in Wideband Code Division Multiple Access (WCDMA...A mobile transmission strategy, PMPatching (Proxy-based Mobile Patching) transmission strat-egy is proposed, it applies to the proxy-based mobile streaming media system in Wideband Code Division Multiple Access (WCDMA) network. Performance of the whole system can be improved by using patching stream to transmit anterior part of the suffix that had been played back, and by batching all the demands for the suffix arrived in prefix period and patching stream transmission threshold period. Experimental results show that this strategy can efficiently reduce average network transmission cost and number of channels consumed in central streaming media server.展开更多
Increment of mobile cloud video motivates mobile users to utilize cloud storage service to address their demands, cloud storage provider always furnish a location-independent platform for managing user＇s data. Howeve...Increment of mobile cloud video motivates mobile users to utilize cloud storage service to address their demands, cloud storage provider always furnish a location-independent platform for managing user＇s data. However, mobile users wonder if their cloud video data leakage or dynamic migration to illegal service providers. In this paper, we design a novel provable data possession protocol based on data geographic location attribute, which allows data owner to auditing the integrity of their video data, which put forward an ideal choice for remote data possession checking in the mobile cloud storage. In our proposed scheme, we check out whether the video data dynamic migrate to an unspecified location （such as： overseas） by adding data geographic location attribute tag into provable data possession protocol. Moreover, we make sure the security of our proposed scheme under the Computational Diffic-Hellman assumption. The analysis and experiment results demonstrate that our proposed scheme is provably secure and efficient.展开更多
Environmental pollution and energy crisis are two major global challenges to human beings.Recovering energy from wastewater is considered to be one of the effective approaches to address these two issues synchronously...Environmental pollution and energy crisis are two major global challenges to human beings.Recovering energy from wastewater is considered to be one of the effective approaches to address these two issues synchronously.As the main pollutants in wastewater,toxic heavy metal ions are the potential candidates for energy storage devices with pseudocapacitive behaviors.In this study,toxic metal ions of Cr(VI)and Cu(II)are removed efficiently by chitosan coated oxygen-containing functional carbon nanotubes,and the corresponding equilibrium adsorption capacity is 142.1 and 123.7 mg g^(-1).Followed by carbonization of metal ions-adsorbed adsorbents,Cu-and Cr N-loaded carbon composites can be obtained.Electrochemical measurements show that the supercapacitor electrodes based on Cu-and Cr N-loaded carbon composites have specific capacitance of 144.9 and 114.9 F g^(-1)at2 m V s^(-1),with superior electrochemical properties to pure chitosan coated carbon nanotubes after carbonization.This work demonstrates a new strategy for the resource-utilization of other heavy metal ions for energy devices,and also provides a new way to turn environmental pollutants into clean energy.展开更多
The proliferation of mobile devices in society accessing data via the ＂cloud＂ is imposing a dramatic increase in the amount of information to be stored on hard disk drives （HDD） used in servers. Forecasts are that...The proliferation of mobile devices in society accessing data via the ＂cloud＂ is imposing a dramatic increase in the amount of information to be stored on hard disk drives （HDD） used in servers. Forecasts are that areal densities will need to increase by as much as 35% compound per annum and by 2,020 cloud storage capacity will be around 7 zettabytes corresponding to areal densities of 2 Tb/in^2. This requires increased performance from the magnetic pole of the electromag- netic writer in the read/write head in the HDD. Current state-of-art writing is undertaken by morphologically complex magnetic pole of sub 100 nm dimensions, in an environment of engineered magnetic shields and it needs to deliver strong directional magnetic field to areas on the recording media around 50 nm × 13 nm. This points to the need for a method to perform direct quantitative measurements of the magnetic field generated by the write pole at the nanometer scale. Here we report on the complete in situ quantitative mapping of the magnetic field generated by a functioning write pole in operation using electron holography. The results point the way towards a new nanoscale magnetic field source to further develop in situ transmission electron microscopy.展开更多
文摘A new ROMless twiddle factor generator for radix-2 1024-point FFT is proposed.It consists of several simple logic units and each of them synthesizes some data,which will be used to compose the twiddle factors.The power analysis with Synopsys Power Compiler shows that it consumes about 2mW with TSMC 0.25μm CMOS process at 50MHz.This twiddle factor generator is designed for the low power applications,especially for the mobile communications and other portable devices...
文摘GIS applications to mobile devices are becoming i nc reasingly popular, utilizing a di-verserange of devices. Many of these devices suffer from serious constraints in three main areas: processor speed, memory space and screen size. This paper presents a GIS application, called "MacaoMap", that is intended for heavily resource-co nstrained handheld devices. MacaoMap is a tourism-oriented map application of t he Macao territory for PalmOS and Pocket PC personal digital assistants. It was designed to perform satisfactorily on devices with as little as 16 MHz processor speed, and requires only 500 KB available memory for the GIS application and al l GIS data. Memory requirements are kept low through a specially designed data f ormat. The main challenge of satisfactory map drawing speed is addressed through a variety of techniques that were developed for this application. The paper des cribes the application’s data format, outlines the map drawing techniques, and points out the areas for future development.
基金The National Natural Science Foundation of China( No. 60902008)the Key Laboratory Hi-Tech Program of Changzhou City( No. CM20103003)+1 种基金the Key Laboratory Program of Information Network Security of Ministry of Public Security (No. C12602)the Science and Technology Supporting Project of Changzhou City ( No. CE20120030)
文摘The resilient storage outsourcing schemes in mobile cloud computing are analyzed. It is pointed out that the sharing-based scheme （ShS） has vulnerabilities regarding confidentiality and integrity; meanwhile, the coding-based scheme （COS） and the encryption-based scheme （EnS） have vulnerabilities on integrity. The corresponding attacks on these vulnerabilities are given. Then, the improved protocols such as the secure sharing-based protocol （SShP）, the secure coding-based protocol （SCoP） and the secure encryption- based protocol （SEnP）, are proposed to overcome these vulnerabilities. The core elements are protected through public key encryptions and digital signatures. Security analyses show that the confidentiality and the integrity of the improved protocols are guaranteed. Meanwhile, the improved protocols can keep the frame of the former schemes and have higher security. The simulation results illustrate that compared with the existing protocols, the communication overhead of the improved protocols is not significantly increased.
基金Supported by: (1) Specialized Research Fund for the Doctoral Program of Higher Education (No. 20030013006) (2) National Specialized R&D Project for the Product of Mobile Communications (Develop-ment and Application of Next Generation Mobile Intel-ligent Network)+3 种基金 (3) Development Fund Key Project for Electronic and Information Industry (Core Service Plat-form for Next Generation Network) (4) Development Fund Project for Electronic and Information Industry (Value-added Service Platform and Application System for Mobile Communications) (5) Development Fund Project for Electronic and Information Industry (Con-tent-based Integrated Charging Platform for Telecom-munication Networks) (6) National Specific Project for Hi-tech Industrialization and Information Equipments (Mobile Intelligent Network Supporting Value-added Data Services).
文摘A mobile transmission strategy, PMPatching (Proxy-based Mobile Patching) transmission strat-egy is proposed, it applies to the proxy-based mobile streaming media system in Wideband Code Division Multiple Access (WCDMA) network. Performance of the whole system can be improved by using patching stream to transmit anterior part of the suffix that had been played back, and by batching all the demands for the suffix arrived in prefix period and patching stream transmission threshold period. Experimental results show that this strategy can efficiently reduce average network transmission cost and number of channels consumed in central streaming media server.
基金supported in part by National High Tech Research and Development Program(863 Program)of China(No.2015 AA016005)
文摘Increment of mobile cloud video motivates mobile users to utilize cloud storage service to address their demands, cloud storage provider always furnish a location-independent platform for managing user＇s data. However, mobile users wonder if their cloud video data leakage or dynamic migration to illegal service providers. In this paper, we design a novel provable data possession protocol based on data geographic location attribute, which allows data owner to auditing the integrity of their video data, which put forward an ideal choice for remote data possession checking in the mobile cloud storage. In our proposed scheme, we check out whether the video data dynamic migrate to an unspecified location （such as： overseas） by adding data geographic location attribute tag into provable data possession protocol. Moreover, we make sure the security of our proposed scheme under the Computational Diffic-Hellman assumption. The analysis and experiment results demonstrate that our proposed scheme is provably secure and efficient.
基金supported by the National Natural Science Foundation of China(51602182,21535004,21390411)Shandong Provincial Natural Science Foundation(ZR2016EMQ02,ZR2016BP07)
文摘Environmental pollution and energy crisis are two major global challenges to human beings.Recovering energy from wastewater is considered to be one of the effective approaches to address these two issues synchronously.As the main pollutants in wastewater,toxic heavy metal ions are the potential candidates for energy storage devices with pseudocapacitive behaviors.In this study,toxic metal ions of Cr(VI)and Cu(II)are removed efficiently by chitosan coated oxygen-containing functional carbon nanotubes,and the corresponding equilibrium adsorption capacity is 142.1 and 123.7 mg g^(-1).Followed by carbonization of metal ions-adsorbed adsorbents,Cu-and Cr N-loaded carbon composites can be obtained.Electrochemical measurements show that the supercapacitor electrodes based on Cu-and Cr N-loaded carbon composites have specific capacitance of 144.9 and 114.9 F g^(-1)at2 m V s^(-1),with superior electrochemical properties to pure chitosan coated carbon nanotubes after carbonization.This work demonstrates a new strategy for the resource-utilization of other heavy metal ions for energy devices,and also provides a new way to turn environmental pollutants into clean energy.
文摘The proliferation of mobile devices in society accessing data via the ＂cloud＂ is imposing a dramatic increase in the amount of information to be stored on hard disk drives （HDD） used in servers. Forecasts are that areal densities will need to increase by as much as 35% compound per annum and by 2,020 cloud storage capacity will be around 7 zettabytes corresponding to areal densities of 2 Tb/in^2. This requires increased performance from the magnetic pole of the electromag- netic writer in the read/write head in the HDD. Current state-of-art writing is undertaken by morphologically complex magnetic pole of sub 100 nm dimensions, in an environment of engineered magnetic shields and it needs to deliver strong directional magnetic field to areas on the recording media around 50 nm × 13 nm. This points to the need for a method to perform direct quantitative measurements of the magnetic field generated by the write pole at the nanometer scale. Here we report on the complete in situ quantitative mapping of the magnetic field generated by a functioning write pole in operation using electron holography. The results point the way towards a new nanoscale magnetic field source to further develop in situ transmission electron microscopy.
