Heterogeneous object modeling through direct face neighborhood alteration

Two recent advances—the use of functionally gradient materials in parts and layered manufacturing technology—have brought to the forefront the need for design and fabrication methodologies for heterogeneous objects. However, current solid modeling systems, a core component of computer-aided design and fabrication tools, are typically purely geometry based, and only after the modeling of product geometry, can a part's non-geometric attributes such as material composition be modeled. This sequential order of modeling leads to unnecessary operations and over-segmented 3D regions during heterogeneous object modeling processes.

To enable an efficient design of heterogeneous objects, we propose a novel method, direct face neighborhood operation. This approach combines the geometry and material decisions into a common computational framework as opposed to separate and sequential operations in existing modeling systems. We present theories and algorithms for direction face neighborhood alteration, which enables direct alteration of face neighborhood before 3D regions are formed. This alteration is based on set membership classification (SMC) and region material semantics. The SMC is computationally enhanced by the usage of topological characteristics of heterogeneous objects. After the SMC, boundary evaluation is performed according to the altered face neighborhood. In comparison with other solid modeling methods, the direct face neighborhood alteration method is computationally effective, allows direct B-Rep operations, and is efficient for persistent region naming. A prototype system has been implemented to validate the method and some examples are presented.     

Attribute-based key-insulated signature for boolean formula

In order to minimize the impact of secret signing key exposure in attribute-based signature scenario, we construct an attribute-based key-insulated signature (ABKIS) scheme for expressive monotone boolean function access structures utilizing only four pairing operations in verification process and making the signature length constant, that is, the number of pairings required for signature verification and the size of signature are independent of the size of attribute set participated in the respective process. The (strong) key-insulated selective security of our ABKIS scheme is reduced to the computational Diffie–Hellman Exponent problem without using any random oracles. The proposed construction attains signer privacy, which is a fundamental requirement of the signature schemes in the attribute-based setting.     

A semantic geo-catalogue for a local administration

The enhancement of the search capabilities of geo-spatial tools occupies one of the highest positions in the agenda of the INSPIRE initiative. This can be done by equipping applications with tools able to understand user terminology. However, this is in contrast with current approaches, which tend to fix in advance the terminology with a consequent rigidity in the way users interact with the system. In this paper we present the work we have done with the Semantic Geo-Catalogue (SGC) project in providing a semantic extension to the geo-catalogue of the Autonomous Province of Trento (PAT) in Italy. This was done through the adoption of a semantic matching tool and a faceted ontology that codifies knowledge about the geography of the PAT and that was created by reorganizing data extracted from the local geographical dataset. Thanks to the semantic extension, queries to the geo-catalogue are expanded with domain specific terms taken from the ontology thus obtaining a higher number of relevant documents in output. We also complied with the Open Government Data (OGD) initiative by publishing in RDF and by linking to relevant dictionaries some useful data taken from the local repository.     

Impression creep characterization of 90Pb-10Sn microelectronic solder balls at subsolvus and supersolvus temperatures

The creep behavior of Pb-10wt.%Sn, a common high-lead solder used in microelectronic packaging, was studied by impression creep testing of ball-gridarray (BGA) solder balls attached to an organic substrate, both above and below the solvus temperature (408 K). Below the solvus temperature, the solder microstructure consists of roughly equiaxed grains of the Pb-rich solid solution α, which contains <5wt.%Sn in solution, with a coarse dispersion of Sn-rich β precipitates. Here, the creep behavior of the solder is controlled by dislocation climb via dislocation core diffusion, yielding n≈4 and Q≈60 kJ/mole. Above the solvus temperature, where the entire 10wt.%Sn is in solution, the creep mechanism becomes controlled by viscous glide of dislocations, limited by solute drag, with n≈3 and Q≈92 kJ/mole. Based on experimental data, creep equations for the as-reflowed solder in the two temperature regimes are given. Comparison of the present data with those available in the literature showed good agreement with the proposed laws.     

Multilayer Hierarchical Model for Mobility Management in IPv6: A Mathematical Exploration

The mobility solution provided by Mobile IPv6 (MIPv6) imposes too much signaling load to the network and enforces large handoff latency to end user. Hierarchical MIPv6 (HMIPv6) on the other hand, is designed by organizing MIPv6 in layered architecture and performs better than MIPv6 in terms of handoff latency and signaling load. Observation shows that, there is still possibility to shrink the handoff latency and the signaling load by further extending HMIPv6 into multiple layers. To explore this possibility of enhanced performance through layered architecture, this paper aimed at mathematical exploration of an N-layered MIPv6 network architecture in order to figure out the optimal levels of hierarchy for mobility management. A widespread analysis is carried out on various parameters such as location update frequency and cost, handoff latency and packet delivery cost. Influence of queuing delay on handoff latency is examined by modeling M/M/1/K queue in the architecture and user mobility is modeled using Markov chain. Analytical investigation reveals that three levels of hierarchy in MIPv6 architecture provide an optimal solution for mobility management.     

Design considerations for p-i-n thyristor structures

An analysis of a high-voltage gate turn-off (GTO) thyristor structure with a double-layered n base (p-i-n structure) is presented. From integration of Poisson's equation, an expression for the forward-blocking voltage at the onset of avalanche breakdown is obtained. Simple design criteria are developed to calculate the optimal thickness and doping density of the n base of a conventional pnpn structure designed for a specific voltage-blocking capability. The same principle is applied to design for the doping densities and thicknesses of the high-resistivity region and the buffer layer of the p-i-n GTO structure. The forward-blocking voltage, as well as the on-state voltage (at a current density of 300 A cm^-2) is predicted for a wide range of base layer thicknesses and doping densities to illustrate the available tradeoff options. Lowest on-state power dissipation for high blocking voltages (>6000 V) is predicted for a doping level of 5×10¹² cm^-3 in the high-resistivity layer     

Design and performance of the mesh-type high-speed silicon opticalposition-sensitive devices

A high speed optical position-sensitive device (PSD) which was fabricated using a certain structure of the mesh-type resistive layer for reducing the junction capacitance is discussed. Its performance is compared with the conventional type of PSD (CPSD) fabricated by the same technology. The mesh-type high speed PSD (MEPSD) is based on an ion-implanted Si p-i-n structure and has an area of 14×14 mm² with 30-μm strip-width and 125-μm pitch. The temporal response of the MEPSD is found to be improved by a factor of 1.83 times compared to the CPSD. A photosensitivity comparable to that of the CPSD is obtained. Its position linearity for detection is also comparable with that of the CPSD. The performance of the laboratory demonstration devices illustrates the feasibility of the concept for high-speed PSD     

Media-independent pre-authentication supporting secure interdomain handover optimization [architectures and protocols for mobility management in all-IP mobile networks]

Handovers may cause delays and packet losses that affect real-time communication performance. Mobility protocols at several layers are designed to support handover, but they need to be optimized to ensure high-quality application performance. Existing optimization techniques are not sufficient to take care of interdomain and intertechnology handovers involving different access technologies, such as Wi-Fi, GSM, CDMA, and WiMAX. We categorize several types of handover, describe handover delay components, and propose a handover optimization framework called media independent pre-authentication that can provide optimizations for interdomain and intertechnology handover in a manner that is transparent to mobility management protocols. In addition, we also present experimental results demonstrating that this framework can achieve a significant reduction in handover delays for both network-layer and application-layer mobility management protocols.     

Designing and experimentally demonstrating automatic OPS/OCS/OpenFlow network control driven by ChoiceNet provider

Interconnection between our existing optical packet and circuit integrated network (OPCInet) and an ecosystem for network service provisioning named ChoiceNet enables network service providers to provide diverse services and realize control driven by the providers. In this paper, we design and implement control interfaces for the interconnection, which enables each ChoiceNet provider to explicitly control both OPCInet- and OpenFlow-based networks by use of a single common interface with proprietary/easily modifiable message formats for all control functions. We construct an experimental setup between the USA and Japan, and demonstrate that the OPCInet and an OpenFlow-based network placed in Japan are successfully controlled by request from the ChoiceNet provider installed in the USA. We also show that the time required to complete Telnet access to the OPCInet C-plane for each control is no more than 150 ms over the long distance from the USA to Japan.     

Characterization of CdS Nanowires Self-Assembled in a Nanoporous Alumina Template

CdS nanowires were self-assembled in a thin film (～200 nm) anodic aluminum oxide template on an indium tin oxide-coated glass substrate via dc electrodeposition. Raman spectral studies were done to probe the vibrational properties of scattering CdS phonons. Strong 1 longitudinal optical (LO), 2 LO, and 3 LO peaks were observed at 302 cm^?1, 603 cm^?1, and 906 cm^?1 having an energy separation of 37 meV, which is in accordance with the CdS bulk values. The photoluminescence spectra showed improved intensity of emission on annealing of the CdS nanowires. Field-emission scanning microscopy confirms the growth of nanowires of diameters ranging from 10 nm to 25 nm for these templates. These diameters agreed with those extracted from the luminescence emission energies.