Digital distance functions on three-dimensional grids

In this paper, we examine five different three-dimensional grids suited for image processing. Digital distance functions are defined on the cubic, face-centered cubic, body-centered cubic, honeycomb, and diamond grids. We give the parameters that minimize an error function that favors distance functions with low rotational dependency. We also give an algorithm for computing the distance transform—the tool by which these distance functions can be applied in image processing applications.     

A constrained EPSAC approach to inventory control for a benchmark supply chain system

The design of an appropriate inventory control policy for a supply chain (SC) plays an essential role in tempering inventory instability and bullwhip effect. Several constraints are commonly encountered in actual operations so managers are required to take these physical restrictions into account when designing the inventory control policy. Model predictive control (MPC) appears as a promising solution to this issue, due to its capability of finding optimal control actions for a constrained SC system. Therefore, the inventory control problem for a benchmark SC is solved using the extended prediction self-adaptive control approach to MPC. To extend methodologies in our previous work, the control framework relies on generic process model and incorporates the physical constraints arising from practical operations to form the general constrained optimisation problems. The managers can choose from decentralised and centralised control structures according to specific informational and organisational factors of their SCs. The proposed control schemes in this study may be appropriate for industrial practice because the designed policy can bring a reduction of over 30% in operating cost and a significant increase of customer satisfaction level compared with that of the conventional policy.     

Cooperative use of unmanned sea surface and micro aerial vehicles at Hurricane Wilma

On Oct. 24, 2005, Hurricane Wilma, a category 5 storm, made landfall at Cape Romano, Florida. Three days later, the Center for Robot‐Assisted Search and Rescue at the University of South Florida deployed an iSENYS helicopter and a prototype unmanned water surface vehicle, AEOS‐1, to survey damage in parts of Marco Island, 14 km from landfall. The effort was the first known use of unmanned sea surface vehicles (USVs) for emergency response and established their suitability for the recovery phase of disaster management by detecting damage to seawalls and piers, locating submerged debris (moorings and handrails), and determining safe lanes for sea navigation. It provides a preliminary domain theory of postdisaster port and littoral inspection with unmanned vehicles for use by the human–robot interaction community. It was also the first known demonstration of the strongly heterogeneous USV–micro aerial vehicle (MAV) team for any domain. The effort identified cooperative UAV–USV strategies and open issues for autonomous operations near structures. The effort showed that the MAV provided a much‐needed external view for situation awareness and provided spotting for areas to be inspected. Concepts of operations for USV damage inspection and USV–MAV cooperation emerged, including a formula for computing the human–robot ratio: N_h = (2 × N_v) + 1, where N_h is the number of humans and N_v is the number of vehicles. The outstanding research issues span three areas: challenges for USVs operating near littoral structures, general issues for USV–MAV cooperation, and new applications. It is expected that the lessons learned will be transferrable to defense and homeland safety and security applications, such as port security, and other phases of emergency response, including rescue. © 2008 Wiley Periodicals, Inc.     

Low-temperature evolution of the proton magnetic resonance line shape in β-phase palladium hydride

Measurements of the proton magnetic resonance absorption line shape in -phase palladium hydride indicate that there is no short-range ordering associated with the order-disorder phase transition that occurs in the neighborhood of 50 K. However, measurements of the line shape in the range 10–30 K show a change from a Gaussian to a non-Gaussian profile. This effect is not related to the order-disorder phase transition. A possible explanation in terms of thermally assisted tunneling is proposed.     

Datenbankunterstützung für den ingenieurwissenschaftlichen Entwurf

Zusammenfassung Datenbanksysteme zeichnen sich durch Charakteristika aus, die über den klassischen administrativ-betriebswirtschaftlichen Bereich hinaus zunehmend auch für Ingenieuranwendungen als vorteilhaft erkannt werden. Die Schwierigkeiten für einen sofortigen Einsatz in diesem Sektor liegen darin, daß existierende Systeme hinsichtlich Datenstrukturierung, Konsistenz, Mehrbenutzerbetrieb und Datensicherung keine den neuen Anforderungen entsprechenden Konzepte anbieten. Der Bericht nennt beispielhaft für den Bereich des Entwurfs technischer Objekte die wichtigsten Unterschiede zu traditionellen Anwendungen und stellt Lösungsvorschläge für die genannten Problemkreise vor.     

Reactively sputtered TiO2 layers on SnO2:F substrates: A Raman and surface photovoltage study

DC reactively sputtered TiO₂ layers on SnO₂:F substrates were investigated by Raman and surface photovoltage spectroscopy. The stoichiometry and layer thicknesses were investigated by elastic recoil detection analysis. The deposition temperature, the O₂/(O₂ + Ar) ratio and the deposition time were varied systematically. With increasing temperature, the layers become crystalline with the rutile modification dominating. Rutile phase preferentially forms on vertical facets of SnO₂ crystallites. Anatase phase starts to form during prolonged deposition and at lower O₂/(O₂ + Ar) ratios. The energy of the exponential absorption tails below the band gap, a measure of the defect density of the films, is determined by the deposition temperature and not by other parameters if the deposition temperature is relatively high, irrespective of the content of crystalline phases or the value of the band gap. Charge separation takes place at length scales significantly shorter than the layer thicknesses (diffusion length less than 6 nm). TiO₂ films sputtered at 380 °C show rectifying behaviour with a carbon contact.     

Direct spectroscopic evidence of energy transfer from photo-excited semiconducting polymers to single-walled carbon nanotubes

Single-walled carbon nanotubes have been efficiently dispersed in an organic solvent using the semiconducting polymers MEHPPV and PFO. It has been found that energy is transferred to the carbon nanotubes when the polymer is photo-excited across its minimum energy gap. This is shown using photoluminescence excitation mapping in the range of both the polymer's and the nanotube's optical absorbance. Possible mechanisms for the energy transfer are discussed.     

Introduction. Carbon-based electronics: fundamentals and device applications

Carbon-based materials offer a number of exciting possibilities for both new science and applications. Many of these are based on the novel band structure of graphene, by which solids mimic the properties of relativistic fermions and which offers the potential for high speed nanoscale electronics. When sheets of graphene are rolled up to make carbon nanotubes, further interesting properties are found; for example, both semiconducting and metallic nanotubes able to be produced. The novel properties of these new materials, together with the already remarkable properties of diamond itself, are discussed by a series of experts who came together in May 2007 to discuss and debate the potential for future development.     

Silicon Lens Optimization to Create Diffuse,Uniform Illumination from Incoherent THz Source Arrays

Journal of Infrared, Millimeter, and Terahertz Waves - Arrays of terahertz (THz) sources provide a pathway to overcoming the radiation power limitations of single sources. Several independent...