Coupled electro-thermal modeling and optimization of clock networks

In this paper a coupled electro-thermal model is used for the optimal design of the clock distribution tree of a high performance microprocessor. Such approach allows simultaneously to take into account both thermal and electrical constraints. In particular timing issues such as clock delay from the root of the tree to the leaves and skew between the leaves are optimized by a suitable wire and buffer sizing. At the same time the lifetime constraints of clock wires that are affected by the electromigration, enhanced by the high temperature reached in interconnects due to the Joule self-heating, are checked and respected.     

Challenges for the security analysis of Next Generation Networks

The increasing complexity of information and telecommunications systems and networks is reaching a level beyond human ability, mainly from the security assessment viewpoint. Methodologies currently proposed for managing and assuring security requirements fall short of industrial and societal expectations. The statistics about vulnerabilities and attacks show that the security, reliability and availability objectives are not reached and that the general threat situation is getting worse. With the deployment of Next Generation Networks – NGNs, the complexity of networks, considering their architecture, speed and amount of connections, will increase exponentially. There are several proposals for the network and security architectures of NGNs, but current vulnerability, threat and risk analysis methods do not appear adequate to evaluate them. Appropriate analysis methods should have some additional new characteristics, mainly regarding their adaptation to the continuous evolution of the NGNs. In addition, the application of security countermeasures will require technological improvements, which will demand further security analyses. This paper evaluates the current vulnerability, threat and risk analysis methods from the point of view of the new security requirements of NGNs. Then, the paper proposes to use autonomic and self-adaptive systems/applications for assuring the security of NGNs.     

Encoded 16-PSK: a study for the receiver design

The authors present the results of a design study of the receiver in a digital transmission system using the combined coding and modulation schemes known as Ungerboeck codes. Specifically, they examine the design of the receiver for encoded 16-PSK (phase shift keying) modulation, presenting first the traditional structure for the optimum receiver and then a simpler structure. The decoding depth of the Viterbi algorithm, the quantization of the metrics inside the Viterbi processor, and the phase jitter in the recovered carrier are considered. The impact of branch and path metric quantization inside the receiver is discussed, showing that a reasonable number of bits (8) is sufficient to obtain nearly optimum performance when the code complexity is limited. The effect of imperfect carrier recovery inside the receiver is studied, providing accurate analytical estimates of the error event probability as well as an upper bound to the symbol error probability. Results of a detailed simulation, including carrier and bit timing recovery blocks, show that the effects of imperfections on the bit error probability are very small, even at low signal-to-noise ratios. On the whole, results show the robustness of the Viterbi algorithm with respect to fairly rough quantizations of the metrics and indicate that carrier recovery is not as critical as expected     

Reduction in personal exposures to particulate matter and carbon monoxide as a result of the installation of a Patsari improved cook stove in Michoacan Mexico

The impact of an improved wood burning stove (Patsari) in reducing personal exposures and indoor concentrations of particulate matter (PM(2.5)) and carbon monoxide (CO) was evaluated in 60 homes in a rural community of Michoacan, Mexico. Average PM(2.5) 24-h personal exposure was 0.29 mg/m(3) and mean 48-h kitchen concentration was 1.269 mg/m(3) for participating women using the traditional open fire (fogon). If these concentrations are typical of rural conditions in Mexico, a large fraction of the population is chronically exposed to levels of pollution far higher than ambient concentrations found by the Mexican government to be harmful to human health. Installation of an improved Patsari stove in these homes resulted in 74% reduction in median 48-h PM(2.5) concentrations in kitchens and 35% reduction in median 24-h PM(2.5) personal exposures. Corresponding reductions in CO were 77% and 78% for median 48-h kitchen concentrations and median 24-h personal exposures, respectively. The relationship between reductions in median kitchen concentrations and reductions in median personal exposures not only changed for different pollutants, but also differed between traditional and improved stove type, and by stove adoption category. If these reductions are typical, significant bias in the relationship between reductions in particle concentrations and reductions in health impacts may result, if reductions in kitchen concentrations are used as a proxy for personal exposure reductions when evaluating stove interventions. In addition, personal exposure reductions for CO may not reflect similar reductions for PM(2.5). This implies that PM(2.5) personal exposure measurements should be collected or indoor measurements should be combined with better time-activity estimates, which would more accurately reflect the contributions of indoor concentrations to personal exposures. PRACTICAL IMPLICATIONS: Installation of improved cookstoves may result in significant reductions in indoor concentrations of carbon monoxide and fine particulate matter (PM(2.5)), with concurrent but lower reductions in personal exposures. Significant errors may result if reductions in kitchen concentrations are used as a proxy for personal exposure reductions when evaluating stove interventions in epidemiological investigations. Similarly, time microenvironment activity models in these rural homes do not provide robust estimates of individual exposures due to the large spatial heterogeneity in pollutant concentrations and the lack of resolution of time activity diaries to capture movement through these microenvironments.     

Multiplierless, Folded 9/7– 5/3 Wavelet VLSI Architecture

This brief proposes a multiplierless VLSI architecture for the famous 9/7 wavelet filters. The novelty of this architecture is the possibility to compute the 5/3 wavelet results into the 9/7 data path with a reduced number of adders compared to other solutions. The multiplierless architecture has been characterized in terms of performance through simulations into a JPEG2000 environment and compared to other solutions. Implementation on a 0.13-mum standard cell technology shows that the proposed architecture compared to other multiplierless architectures requires a reduced amount of logic with excellent performance.     

PROXIMA: PROlog eXecutIon MAchine

The design and the technological aspects involved in the integration of a high-performance Prolog machine on silicon are described. Many Prolog machines have been implemented by using a large number of boards. Consequently they are expensive, cumbersome, and not yet achievable by industrial standards. There have been many attempts in the US, Japan, and Europe to integrate Prolog engines in silicon, in order to increase performance. The described processor, PROXIMA (PROlog eXecutIon MAchine), is a VLSI Prolog engine suitable to be added onto a commercial workstation. The PROXIMA chip set has been integrated in silicon using a double-metal 0.8 μm n-well SGS-Thomson proprietary CMOS technology     

Italian guidelines for the management of infectious complications in pediatric oncology: empirical antimicrobial therapy of febrile neutropenia

The Italian Association for Paediatric Haematology and Oncology prepared a guideline document aimed at unifying and rationalising as much as possible the management of febrile neutropenia in children with cancer, because of the potential impact of these procedures on hospital costs and on the development of antibiotic resistance. Before starting anti-infective therapy, at least 2 blood cultures, a throat swab, urine-culture, and cultures from any suspected infected site, should be performed. Routine chest X-rays at onset of febrile neutropenia are probably not necessary, in absence of respiratory signs. At the present time, the safer option probably remains the combination of a beta-lactam and an aminoglycoside, and treating febrile neutropenia outside of hospital should be considered an investigational approach. The choice of the most appropriated regimen for each institution should be based also on the local bacteriological statistics and patterns of bacterial resistance. Antibiotic toxicity and cost should be other important factors. Every subsequent addition or substitution of antibiotics should be based on objective signs of clinical deterioration. The only accepted empirical modification is empirical antifungal therapy, while the empirical addition of a glycopeptide antibiotic cannot be recommended.     

Power Supply Design Parameters for Switching-Noise Control in Deep-Submicron Circuits Design Flows

In high performance integrated circuits phenomena like crosstalk, IR drops, electromigration and ground bounce are assuming increasing proportions because of the growing complexity in ultra deep submicron designs: their effects are assuming increasing impact compromising circuits functionality and not only their performances.This paper suggests a methodology to evaluate and to prevent power supply noise generation in more and more increasing dimensions circuit blocks. The power supply busses modeling is addressed to find out actual parameters to face early in the design phase noise phenomena related to power distribution. In particular using the equations reported in this paper the designer has the possibility to control the global power bus noise generation depending on the design strategy used, on the library characteristics and on the given performance constraints.The appropriateness of the developed methodology seems to be helpful if applied during the circuit design flow in conjunction with a project tool having as a target noise reduction besides delay and power optimization.