An exploration of user-generated wireless broadband infrastructures in digital cities

This paper examines the broadband connectivity options available in digital cities. It offers an overview of services provided by commercial operators, the public sector and by citizens themselves, arguing that shortcomings in existing fixed broadband and commercial mobile broadband services provide an opportunity for citizens to share their own wireless broadband connections. It explores Wi-Fi hotspot provider FON’s approach to extending mobile broadband infrastructure by enabling shared connections within communities. The paper outlines some reasons why this specific user-generated approach to infrastructure provision has been unable to deliver highly robust broadband infrastructure, and discusses ways in which users and the public sector can be involved in developing new mobile infrastructures that will meet citizens’ needs.     

A hierarchical test generation methodology for digital circuits

A new hierarchical modeling and test generation technique for digital circuits is presented. First, a high-level circuit model and a bus fault model are introduced—these generalize the classical gate-level circuit model and the single-stuck-line (SSL) fault model. Faults are represented by vectors allowing many faults to be implicitly tested in parallel. This is illustrated in detail for the special case of array circuits using a new high-level representation, called the modified pseudo-sequential model, which allows simultaneous test generation for faults on individual lines of a multiline bus. A test generation algorithm called VPODEM is then developed to generate tests for bus faults in high-level models of arbitrary combinational circuits. VPODEM reduces to standard PODEM if gate-level circuit and fault models are used. This method can be used to generate tests for general circuits in a hierarchical fashion, with both high- and low-level fault types, yielding 100 percent SSL fault coverage with significantly fewer test patterns and less test generation effort than conventional one-level approaches. Experimental results are presented for representative circuits to compare VPODEM to standard PODEM and to random test generation techniques, demonstrating the advantages of the proposed hierarchical approach.     

PDM: A versatile digital transmission system for video

This report discusses a pulse density modulation (PDM) video transmission system. PDM is a one-bit digital coding scheme with advantages of transparency due to an inherently extended signal bandwidth and relatively simple decoding; these make it ideal for a variety of applications. The system outlined is designed to carry a single analogue video channel, together with several sound channels, over a 140 or 280 Mbit/s digital transmission-link. An alternative option to the sound channels will be to carry a 2.048 Mbit/s data channel. Since the analogue video input will be PDM coded, this will enable the system to carry video formats which have a flat base-band frequency response requirement of in excess of 20 MHz (such as HDTV), allowing a large degree of flexibility in use.     

A codec for HDTV signal transmission through terrestrial and satellite digital links

A codec for digital transmission of HDTV is described. The bit-rate compression algorithm is based on advanced techniques such as spatial discrete cosine transform (DCT), temporal differential PCM (DPCM), variable length coding. The codec is designed to operate with both the interlaced studio systems 1125/60 and 1250/50, and, thanks to the inherent flexibility of the packet structure, a wide range of line bit-rates can be used as a compromise between video quality and bit-rate constraints of the digital transmission link. The flexibility of the HDTV codec is highlightened through examples of applications over satellite digital links in practical situations.     

Educational Data Mining: A review of evaluation process in the e-learning

Due to the growing interest in e-learning as an important process of teaching and learning, new mechanisms to evaluate its pedagogical effectiveness are necessaries. This review describes the scenario of 20 years corresponding to data mining research where the context is the e-learning and the main subject is the evaluation aspect, which is considered a latent problem within this environment. Our goal is to provide an unexplored review of EDM research of the teaching and learning process considering the educational perspective. In order to obtain a more wide and complete review, the search of the bibliographic material was realized with the terms “data mining” and “education” which resulted in 525 articles. As exclusion criterion, articles that did not emphasize the improvement of the teaching and learning process were discarded, resulting in 72 articles. As result of our review, the analyzed papers show that the researches in EDM expanded into several areas and themes, for example, oriented studies on interactions between the educational actors, monitoring, and evaluation of teaching-learning process, administrators’ evaluation about the adopted pedagogical actions, learning risks, and recommendation and recovery of educational media. The review allowed to present perspectives, identify trends and observe potential research directions, such as behavioral research, collaboration, interaction and performance in the development of teaching-learning activities.     

A practical design of digital watermarking for video streaming services

A practical design of digital watermarking for video streaming services is proposed in this research. The information of a legitimate recipient is represented as a watermark, which is embedded in the video stream to serve as a cue to trace the recipient in case a clone of the video is illegally distributed. The watermark signals are designed to embed in some areas of video frames to benefit the video stream server, as the result of only partial actions required, including decoding, processing and re-encoding. The invariance of feature points and the self-similarity of hidden signals are further exploited to enable watermark detection without involving the original video. The watermark can decently survive transcoding processes and geometrical modifications of frames. The experimental results demonstrate the advantages of the proposed scheme in terms of watermark visibility, capacity and detection methodology.     

The challenge of e-participation in the digital city: Exploring generational influences among community telecentre users

A primary challenge for the development of e-government and the digital city is participation by low-income, older and technology-challenged citizens. This paper reports on the role of inter-generational interactions in community telecentres in facilitating low-income, older and technology-challenged citizens in gaining access and using digital city infrastructure. Our research also finds that virtual communities are playing a role in supporting e-participation among older, technology-challenged citizens. We examine the influence and interaction of members of offline communities, who use telecentres, on virtual community participation. These communities and telecentres can provide support for the provision of e-services and the development of the digital city. We explore these issues based on empirical field research in community-based telecentres in a developing country. Inter-generational interactions are explored through an analysis using social networks, social identity and social representations theories.     

Multiresolution coding techniques for digital television: A review

Multiresolution decompositions for video coding are reviewed. Both nonrecursive and recursive coding schemes are considered. In nonrecursive schemes, it is shown that pyramid structures have certain advantages over subband or wavelet techniques, and a specific spatiotemporal pyramid coding of HDTV is discussed in some detail. It is shown that recursive, DPCM like schemes will incur a slight loss of optimality due to a restricted form of prediction if multiresolution decomposition with compatible decoding is required. Compatibility and transmission issues are also discussed. Multiresolution transmission for digital broadcast TV is introduced. This, when combined with multiresolution source coding, achieves spectrum efficiency, robustness and graceful degradation under channel impairments.Invited PaperWork supported in part by the National Science Foundation under grants ECD-88-11111, MIP-90-14189 and Bell Communications Research.Work supported by the National Science Foundation under grants ECD-88-11111. K.M. Uz is now with David Sarnoff Research Center in Princeton, NJ 08543.     

A two-level reconfigurable architecture for digital signal processing

This paper describes a novel reconfigurable architecture for digital signal processing (DSP). This architecture consists of a two-level array of cells and interconnections. On the upper level, fundamental DSP operations such as multiplication and addition are mapped onto blocks of 4-bit cells. On the lower level, each cell uses a 4 × 4 matrix of smaller “elements” to perform the necessary computations. Cells also contain pipeline latches for increased throughput. The architecture features a simple VLSI implementation that combines the flexibility of memory elements with the speed of DOMINO logic. Initial prototypes have been fabricated using a modest 0.5-μm CMOS technology. Circuit simulations of the cell in 0.25-μm technology indicate that the design achieves a clock frequency of 200 MHz.     

A feature-based digital watermarking scheme for halftone image

It is a challenging work to design a robust halftone image watermarking scheme against desynchronization attacks. In this paper, we propose a feature-based digital watermarking method for halftone images with low computational complexity, good visual quality and reasonable resistance toward desynchronization attacks. Firstly, the feature points are extracted from host halftone image by using multi-scale Harris–Laplace detector, and the local feature regions (LFRs) are constructed according to the feature scale theory. Secondly, discrete Fourier transform (DFT) is performed on the LFRs, and the embedding positions (DFT coefficients) are selected adaptively according to the magnitude spectrum information. Finally, the digital watermark is embedded into the LFRs by quantizing the magnitudes of the selected DFT coefficients. By binding the watermark with the geometrically invariant halftone image features, the watermark detection can be done without synchronization error. Simulation results show that the proposed scheme is invisible and robust against common signals processing such as median filtering, sharpening, noise adding, and JPEG compression, etc., and desynchronization attacks such as rotation, scaling, translation (RST), cropping, local random bend, and print-scan, etc.     

A new compensation mechanism for environmental parameter fluctuations in CMOS digital ICs

Process-induced and environmental fluctuations play an important role in the design process for modern high-performance integrated circuits. The conventional principle of considering the verification of worst-case requirements reduces the performance that can potentially be achieved by circuits and technology. This paper presents a new mechanism that permits the compensation of random independent delay fluctuations due to environmental factors. It shows that it is significantly possible to reduce the latency time of a circuit even for a moderate length of pipeline stages.     

MPEG-M: A digital media ecosystem for interoperable applications

MPEG-M is a suite of ISO/IEC standards (ISO/IEC 23006) that has been developed under the auspices of Moving Picture Experts Group (MPEG). MPEG-M, also known as Multimedia Service Platform Technologies (MSPT), facilitates a collection of multimedia middleware APIs and elementary services as well as service aggregation so that service providers can offer users a plethora of innovative services by extending current IPTV technology toward the seamless integration of personal content creation and distribution, e-commerce, social networks and Internet distribution of digital media.     

高校人员考核系统的设计与实现

高校人员考核评价是高校人事管理的基础性工作,也是深化高校人事制度改革的重要举措.为了保证考核工作的公开、公平、公正,使"阳光操作"成为现实.本系统的设计结合计算机网络先进技术,运用计算机自动处理考核结果,减少考核的工作量,对改进管理机关工作作风、提高工作效率和服务质量起到了显著的作用.     

A digital calibration algorithm for implementing accurate on-chip resistors

A digital calibration algorithm that provides a systematic method for implementing accurate integrated resistors without compromising linearity or noise performance is described. The technique uses a single external resistor as a reference to implement multiple, different valued integrated resistors without requiring any accurate reference voltage. The algorithm provides a method to calibrate several on-chip resistors without replicating the calibration circuit, and it can achieve an arbitrary accuracy limited only by the external resistor’s accuracy and mismatch errors. Terminations for two high speed wire line transceivers are implemented using the algorithm and simulations and measurements results show adequate performance across process, temperature, and supply voltage. Ayman A. Fayed was born Egypt, in 1975. He received the B.Sc. degree from the Electronics and Communications Department, Cairo University, Cairo, Egypt in 1998, and the M.Sc. and Ph.D. degrees from The Ohio State University, Columbus, in 2000 and 2004 respectively. Since 2002, he has been with Texas Instruments Inc. as an analog and mixed-signal circuit designer. He has been a key contributor to TI#x2019;s high-speed wire line transceivers product line. He has been awarded two US patents in the field. His research interests include mixed-signal CMOS circuit design for high-speed wire line transceivers, adaptive equalization, and power management systems. Mohammed Ismail has over 20 years experience of R&D in the fields of analog, RF and mixed signal integrated circuits. He has held several positions in both industry and academia and has served as a corporate consultant to nearly 30 companies in the US, Europe and the Far East. His current interest lies in research involving digitally programmable/configurable fully integrated radios with focus on low voltage/low power first-pass solutions for 3G and 4G wireless handhelds. He publishes intensively in this area and has been awarded 11 patents. He has co-edited and coauthored several books including a text on Analog VLSI Signal and Information Processing, (McGraw Hill). His last book (2004) is entitled CMOS PLLs and VCOs for 4G wireless, Springer. He co-founded ANACAD Egypt (now part of Mentor Graphics, Inc.) and Spirea AB, Stockholm (now Firstpass Semiconductors AB), a developer of CMOS radio and mixed signal IPs for handheld wireless applications. Dr. Ismail has been the recipient of several awards including the US National Science Foundation Presidential Young Investigator Award, the US Semiconductor Research Corp Inventor Recognition Awards in 1992 and 1993, and a Fulbright/Nokia fellowship Award in 1995. He is the founder of the International Journal of Analog Integrated Circuits and Signal Processing, Springer and serves as the Journal’s Editor-In-Chief. He has served as Associate Editor for many IEEE Transactions, was on the Board of Governors of the IEEE Circuits and Systems Society and is the Founding Editor of “The Chip” a Column in The IEEE Circuits and Devices Magazine. He is a Fellow of IEEE. He obtained his BS and MS degrees in Electronics and Communications from Cairo University, Egypt and the PhD degree in Electrical Engineering from the University of Manitoba, Canada.     

A commutative digital image watermarking and encryption method in the tree structured Haar transform domain

In this paper a commutative watermarking and ciphering scheme for digital images is presented. The commutative property of the proposed method allows to cipher a watermarked image without interfering with the embedded signal or to watermark an encrypted image still allowing a perfect deciphering. Both operations are performed on a parametric transform domain: the Tree Structured Haar transform. The key dependence of the adopted transform domain increases the security of the overall system. In fact, without the knowledge of the generating key it is not possible to extract any useful information from the ciphered-watermarked image. Experimental results show the effectiveness of the proposed scheme.     

Saw and digital technologies in mutlicarrier demodulators

One key technology, for the implementation of future on-board processing payloads, is the multicarrier demodulator (MCD). The MCD is instrumental in allowing FDMA/TDM access schemes which optimize the use of on-board and ground resources in VSAT networks. This paper deals with the analogue and digital implementations of MCD, trying to assess the fields of application of each of the two technologies.     

A simple neuro-fuzzy method for improving the performances of impulse noise filters for digital images

A novel method for improving the performances of impulse noise filters is presented. The method enhances the performance of an impulse noise filter in two ways: increases its noise-suppression ability and decreases its distortion effects. The method is based on a simple 2-input 1-output neuro-fuzzy system. The internal parameters of the system are tuned by training. Training of the system is easily accomplished by using a simple computer-generated artificial image. The proposed method can easily be used with any impulse noise removal operator. The application of the method is completely independent of the noise removal operator and it has no influence on the filtering behavior of the operator. Experimental results show that the proposed method may efficiently be used with any type of impulse noise removal operator to significantly improve its filtering performance.     

Gender digital divide in Rwanda: A qualitative analysis of socioeconomic factors

This study aims at exploring how information and communications technology (ICT) is accessed and used by women and men in Rwanda. Specifically, we analyze the factors that contribute to the gender digital divide in Rwanda. In addition, we assess the importance of equal access to ICTs between genders. Rwanda is a particulary interesting case study, since previous studies on gender differences in the usage and accessibility of ICTs have focused on Western countries, while Africa, and Rwanda in particular, have been less covered. The qualitative method of in-depth interviews was used to collect the data. Interviews were analyzed using a thematic analysis technique. The findings of this study reveal that a gender digital divide still exists in Rwanda, even though the government puts forth much effort to eradicate this phenomenon. Reasons for barriers for women’s access to ICTs were found in social, economic and cultural factors, such as feelings of lack of self-worth, self-confidence, and proper educations; heavy domestic responsibilities; and computer anxiety. The findings also indicated that equal access to ICTs would be a shortcut to economic growth in Rwanda. This study concludes that Rwandan women need to be better educated in the use of computer technologies. Certain gender-sensitive strategies that guide the use of ICTs in this way also need to be established.     

A digital array based bit serial processor for arbitrary window size kernel convolution in vision sensors

The high speed and in-pixel processing of image data in smart vision sensors is an important solution for real time machine vision tasks. Diverse architectures have been presented for array based kernel convolution processing, many of which use analog processing elements to save space. In this paper a digital array based bit serial architecture is presented to perform certain image filtering tasks in the digital domain and hence gain higher accuracies than the analog methods. The presented method benefits from more diverse convolution options such as arbitrary size kernel windows, compared with the digital pulse based approaches. The proposed digital cell structure is compact enough to fit inside an image sensor pixel. When incorporated in a vision chip, resolutions of up to 12 bit accuracy can be obtained in kernel convolution functions with 35×28 μm² layout area usage per pixel in a 90 nm technology. Still, higher accuracies can be obtained with larger pixels. The power consumption of the approach is approximately 10 nW/pixel at a frame rate of 1 kfps.