ARTE: An Application-specific Run-Time managEment framework for multi-cores based on queuing models

This paper presents an Application-specific Run-Time managEment (ARTE) framework to tackle the problem of managing computational resources in an application specific multi-core system. The ARTE framework run-time goal is to minimize applications’ response times while meeting the applications’ computational demands and fitting within the available power budget.     

Efficient architecture/compiler co-exploration using analytical models

The hardware/software co-exploration is a critical phase for a broad range of embedded platforms based on the System-On-Chip approach. Traditionally, the compilation and the architectural design sub-spaces have been explored independently. Only recently, some approaches have analyzed the problem of the concurrent exploration of the compilation/architecture sub-spaces. This paper proposes a framework to support the co-exploration phase of the design space composed of architectural parameters and source program transformations. The objective space is multi-dimensional, including conflicting objectives such as energy and delay. In the proposed framework, heuristic co-exploration techniques based on Pareto Simulated Annealing (PSA) have been used to efficiently explore the architecture/compiler co-design space. A first result of this paper consists of showing how the architecture/compiler co-exploration can be more effective than a traditional two-phase exploration. Since the co-exploration space is quite large, to speed up the co-exploration phase by several orders of magnitude over simulation-based approaches, a methodology based on analytical models has been introduced in the co-exploration framework. The goal of analytical models is to quickly evaluate energy/delay metrics at the systems level, while maintaining accuracy with respect to simulation-based co-exploration. The proposed co-exploration framework has been applied to a parameterized SoC superscalar architecture during the execution of a selected set of multimedia applications.     

Preliminary neutronic assessment of a helium-cooled Li8PbO6 breeding blanket design for DEMO

A preliminary neutronic assessment of the performances of a helium-cooled Li₈PbO₆ breeding blanket for the conceptual design of a DEMO fusion reactor is given. The study mainly focuses on TBR, power density responses and shielding factor optimization to estimate the feasibility of the design under the prescribed radiation deposition limits at TF-coils superconducting magnets. Computational analyses are based on three-dimensional 30° sector using the Monte Carlo code MCNPX 2.6. The scoping interest of helium-cooled Li₈PbO₆ blanket designs is based on a large potential minimization of the amount of Be required and the strong relaxation of ⁶Li enrichment requirements for this solution when compared to other solid breeder blanket options.     

Sex-selection of human spermatozoa: evolution of current techniques and applications

The present paper examines the occurrence of matters relating to the ending of life, including active euthanasia, which is, technically speaking, illegal worldwide. Interest in this most controversial area is drawn from many varied sources, from legal and medical practitioners to religious and moral ethicists. In some countries, public interest has been mobilized into organizations that attempt to influence legislation relating to euthanasia. Despite the obvious international importance of euthanasia, very little is known about the extent of its practice, whether passive or active, voluntary or involuntary. This examination is based on questionnaires completed by 49 national representatives of the International Association for Suicide Prevention (IASP), dealing with legal and religious aspects of euthanasia and physician-assisted suicide, as well as suicide. A dichotomy between the law and medical practices relating to the end of life was uncovered by the results of the survey. In 12 of the 49 countries active euthanasia is said to occur while a general acceptance of passive euthanasia was reported to be widespread. Clearly, definition is crucial in making the distinction between active and passive euthanasia; otherwise, the entire concept may become distorted, and legal acceptance may become more widespread with the effect of broadening the category of individuals to whom euthanasia becomes an available option. The "slippery slope" argument is briefly considered.     

An Optical Interconnect Transceiver at 1550 nm Using Low-Voltage Electroabsorption Modulators Directly Integrated to CMOS

A low-voltage, 90-nm CMOS optical interconnect transceiver operating at 1550-nm optical wavelength is presented. This is the first demonstration of a novel optoelectronic modulator architecture (the quasi-waveguide angled-facet electroabsorption modulator) in a system. It features a simple electronic packaging via flip-chip bonding to silicon. Devices have a broad optical bandwidth, are arrayed two dimensionally, and feature surface normal, spatially separated, and misalignment-tolerant optical ports. The modulators are driven with a novel pulsed-cascode driver capable of supplying an output-voltage swing of 2 V (twice the nominal 1-V CMOS supply) without overstressing thin-oxide core CMOS devices. At the receiver side, a sensitivity of -15.2 dBm is obtained with an integrating/double-sampling front end. The transceiver includes clock generation and recovery circuitry that enables a data serialization factor of five. At a maximum data rate of 1.8 Gb/s, the optical transmitter, receiver, and clocking circuitry consume 12.6, 4.5, and 6.5 mW, respectively, for a total link electrical power dissipation of 23.6 mW. To the best of our knowledge, this is the first demonstration of an interconnect transceiver operating at 1550 nm with a III-V output device directly integrated to the CMOS.     

UHV friction of tribofilms derived from metal dithiophosphates

The friction‐reduction mechanisms of Modtp and Zndtp were highlighted by submitting tribofilms to friction in ultra‐high vacuum (UHV). The use of an UHV tribometer to understand these phenomena is justified by the fact that the friction coefficient recorded in UHV is close to the friction coefficient obtained in traditional tests in oil. After UHV friction, the transfer films on the pin were analyzed by in situ AES, XPS and AES mapping. Low friction is associated with the transfer to the pin of a sulfur‐rich film. In the case of Modtp, we observe a very thin MoS₂ film. The UHV friction coefficient approaches 0.04. In the case of Zndtp, the transfer film contains ZnS together with some phosphates. Because of the poor capacity of ZnS to reduce friction, the UHV friction coefficient recorded is near 0.15. A global model of the action of dithiophosphates in reducing friction is described on the basis of the hard and soft acids and bases (HSAB) principle. This revised version was published online in July 2006 with corrections to the Cover Date.     

Energy Dissipation on Submerged Block Ramps

Block ramps represent structures that produce high energy dissipation and have a unique characteristic of preserving the ecological balance in a river restoration project. The energy dissipation of a block ramp changes with the tailwater level. In this technical note the relative energy dissipation in submerged flow conditions has been investigated. The experiments were conducted at the Hydraulic Laboratory of the University of Pisa, Pisa, Italy on ramps characterized by different block materials, submergence conditions, and ramp slopes. The study shows that the relative energy loss, varying the hydraulic jump location on the ramp, is essentially a function of the scale roughness, the ramp slope, the ratio between the critical water depth, and the ramp height and the ratio between the ramp length and the reduced length in submerged conditions. The differences in energy dissipation for a submerged hydraulic jump in different bed conditions are also investigated.     

Electronic Characterization of Organic Thin Films by Kelvin Probe Force Microscopy

This review highlights the potential of Kelvin probe force microscopy (KPFM) beyond imaging to simultaneously study structural and electronic properties of functional surfaces and interfaces. This is of paramount importance since it is well established that a solid surface possesses different properties than the bulk material. The versatility of the technique allows one to carry out investigations in a non‐invasive way for different environmental conditions and sample types with resolutions of a few nanometers and some millivolts. KPFM can be used to acquire a wide knowledge of the overall electronic and electrical behavior of a sample surface. Moreover, by KPFM it is possible to study complex electronic phenomena in supramolecular engineered systems and devices. The combination of such a methodology with external stimuli, e.g., light irradiation, opens new doors to the exploration of processes occurring in nature or in artificial complex architectures. Therefore, KPFM is an extremely powerful technique that permits the unraveling of electronic (dynamic) properties of materials, enabling the optimization of the design and performance of new devices based on organic‐semiconductor nanoarchitectures.     

Quantitative Measurement of the Local Surface Potential of π‐Conjugated Nanostructures: A Kelvin Probe Force Microscopy Study

We describe a systematic study on the influence of different experimental conditions on the Kelvin probe force microscopy (KPFM) quantitative determination of the local surface potential (SP) of organic semiconducting nanostructures of perylene‐bis‐dicarboximide (PDI) self‐assembled at surfaces. We focus on the effect of the amplitude, frequency, and phase of the oscillating voltage on the absolute surface potential value of a given PDI nanostructure at a surface. Moreover, we investigate the role played by the KPFM measuring mode employed and the tip–sample distance in the surface potential mapping by lift‐mode KPFM. We define the ideal general conditions to obtain a reproducible quantitative estimation of the SP and we find that by decreasing the tip–sample distance, the area of substrate contributing to the recorded SP in a given location of the surface becomes smaller. This leads to an improvement of the lateral resolution, although a more predominant effect of polarization is observed. Thus, quantitative SP measurements of these nanostructures become less reliable and the SP signal is more unstable. We have also devised a semi‐quantitative theoretical model to simulate the KPFM image by taking into account the interplay of the different work functions of tip and nanostructure as well as the nanostructure polarizability. The good agreement between the model and experimental results demonstrates that it is possible to simulate both the change in local SP at increasing tip–sample distances and the 2D potential images obtained on PDI/highly oriented pyrolytic graphite samples. These results are important as they make it possible to gain a quantitative determination of the local surface potential of π‐conjugated nanostructures; thus, they pave the way towards the optimization of the electronic properties of electroactive nanometer‐scale architectures for organic (nano)electronic applications.