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.     

Adoption and sustained use of improved cookstoves

The adoption and sustained use of improved cookstoves are critical performance parameters of the cooking system that must be monitored just like the rest of the stove technical requirements to ensure the sustainability of their benefits. No stove program can achieve its goals unless people initially accept the stoves and continue using them on a long-term basis. When a new stove is brought into a household, commonly a stacking of stoves and fuels takes place with each device being used for the cooking practices where it fits best. Therefore, to better understand the adoption process and assess the impacts of introducing a new stove it is necessary to examine the relative advantages of each device in terms of each of the main cooking practices and available fuels. An emerging generation of sensor-based tools is making possible continuous and objective monitoring of the stove adoption process (from acceptance to sustained use or disadoption), and has enabled its scalability. Such monitoring is also needed for transparent verification in carbon projects and for improved dissemination by strategically targeting the users with the highest adoption potential and the substitution of cooking practices with the highest indoor air pollution or greenhouse gas contributions.     

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     

A Flexible UMTS-WiMax Turbo Decoder Architecture

This work proposes a VLSI decoding architecture for concatenated convolutional codes. The novelty of this architecture is twofold: 1) the possibility to switch on-the-fly from the universal mobile telecommunication system turbo decoder to the WiMax duo-binary turbo decoder with a limited resources overhead compared to a single-mode WiMax architecture; and 2) the design of a parallel, collision free WiMax decoder architecture. Compared to two single-mode solutions, the proposed architecture achieves a complexity reduction of 17.1% and 27.3% in terms of logic and memory, respectively. The proposed, flexible architecture has been characterized in terms of performance and complexity on a 0.13-mum standard cell technology, and sustains a maximum throughput of more than 70 Mb/s.     

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.     

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     

Mediators of immune-complex-induced aggregation of polymorphonuclear neutrophils. II. Platelet-activating factor as the effector substance of immune-induced aggregation

Platelet-activating factor (PAF) is released in vitro during human and rabbit polymorphonuclear neutrophil (PMN) aggregation induced by C5a anaphylatoxin, neutrophil cationic proteins (CP) and their carboxypeptidase-B-derived fragments, C5a des Arg and CP des Arg, as well as phagocytosis of opsonized baker's yeast particles and immune complexes (IC). Purified PAF itself is able to cause in vitro PMN aggregation. By using selective inhibitors, we show that PMN aggregation, induced either by PAF or by other soluble stimuli such as C5a, CP and their des Arg products, follows a similar metabolic pathway, which is both adenosine-diphosphate-(ADP)- and arachidonic acid (AA)- independent. The in vivo injection of purified PAF into rabbits leads both to formation of intravascular PMN aggregates and to development of acute neutropenia, which has the same features as those observed after challenge with IC, C5a and CP. In this respect, electron-microscopic studies of intravascular PMN aggregates in the pulmonary capillary network and glomeruli show identical ultrastructural patterns. Moreover, the intravascular release of PAF is demonstrated after the intravenous injection of IC and temporally correlated with the development of neutropenia. We suggest that PAF is probably the final, common, effector substance of IC-, C5a-, C5a-des-Arg-, CP-, CP-des-Arg-mediated PMN aggregation.