Finding an appropriate radio propagation model for rate aware congestion control mechanism in wireless sensor networks

Wireless Networks - Congestion control techniques are considered to be one of the most imperative ways to overcome various challenges in wireless sensor networks (WSNs). Undeniably, congestion has...     

A model of consumers’ perceptions of the invasion of information privacy

We examined factors that influence an individual's attitude and decisions about the information handling practices of corporations. Results from a survey of 425 consumers suggested that the hypothesized model was an accurate reflection of factors that affect privacy preferences of consumers. The results provide important implications for research and practice. Our study should contribute by initiating an integrative stream of research on the impact of IT and other factors on information privacy perception. For practitioners, our findings suggested that consumers hold corporations, not the IS, responsible for any inappropriate use of personal information. Organizations, therefore, must be proactive in formulating and enforcing information privacy policy in order to address consumers’ concerns.     

Score level fusion of multimodal biometrics using triangular norms

A multimodal biometric system that alleviates the limitations of the unimodal biometric systems by fusing the information from the respective biometric sources is developed. A general approach is proposed for the fusion at score level by combining the scores from multiple biometrics using triangular norms (t-norms) due to Hamacher, Yager, Frank, Schweizer and Sklar, and Einstein product. This study aims at tapping the potential of t-norms for multimodal biometrics. The proposed approach renders very good performance as it is quite computationally fast and outperforms the score level fusion using the combination approach (min, mean, and sum) and classification approaches like SVM, logistic linear regression, MLP, etc. The experimental evaluation on three databases confirms the effectiveness of score level fusion using t-norms.     

ASTERIX: towards a scalable,semistructured data platform for evolving-world models

ASTERIX is a new data-intensive storage and computing platform project spanning UC Irvine, UC Riverside, and UC San Diego. In this paper we provide an overview of the ASTERIX project, starting with its main goal—the storage and analysis of data pertaining to evolving-world models. We describe the requirements and associated challenges, and explain how the project is addressing them. We provide a technical overview of ASTERIX, covering its architecture, its user model for data and queries, and its approach to scalable query processing and data management. ASTERIX utilizes a new scalable runtime computational platform called Hyracks that is also discussed at an overview level; we have recently made Hyracks available in open source for use by other interested parties. We also relate our work on ASTERIX to the current state of the art and describe the research challenges that we are currently tackling as well as those that lie ahead.     

The influence of silica on pore diameter and distribution in PLA scaffolds produced using supercritical CO<Subscript>2</Subscript>

Macroporous polylactide (PLA) scaffolds were fabricated using a supercritical CO₂ foaming process. The addition of silica particles to the polymer matrix resulted in a significant modification in the pore size distribution exhibited by the scaffold. In the absence of silica, the scaffolds contained pores between 88 μm and 980 μm in diameter as determined using X-ray computed microtomography. The addition of silica at only 2 wt% resulted in the elimination of pores of >620 μm, with no significant influence on the total porosity of the material. This effect was attributed to the silica nucleating the formation of gas bubbles in the polymeric material. Although the addition of further silica to the scaffold resulted in a further reduction in modal pore diameter, when more than 20 wt% was added to the matrix little additional effect was noted. In addition to enabling some control over pore diameter, mineral deposition was shown to occur considerably more rapidly on the silica-modified scaffolds than on those containing no silica.     

Quadrefringence of optical vortices in a uniaxial crystal

The splitting of a single optical vortex into four separate ones in a singular beam is theoretically and experimentally described for the propagation of obliquely incident light in a uniaxial crystal. We also find the condition under which the generated vortices in each of the four individual beams propagate independently without changing their structure and have different locations in all beams for any crystal lengths.     

Capacity Planning of Survivable Mesh-based Transport Networks under Demand Uncertainty

Almost all existing work on the design of survivable networks is based on a specific demand forecast to which one optimizes routing and transport capacity assignment for a single target planning view. In practice these single-forecast models may be used repetitively by a planner to consider a range of different scenarios individually, hoping to develop intuition about how to proceed. But this is not the same as having a planning method that can inherently and quantitatively consider a range of possible futures all at once. Our approach considers both the cost of initial design construction and the expected cost of possible augmentations or “recourse” actions required in the future, adapting the network to accommodate different actual future demands. In practice, these recourse actions might include lighting up a new DWDM channel on an existing fiber or pulling-in additional cables, or leasing additional capacity from third party network operators, and so on. A stochastic linear programming approach is used to achieve designs for which the total cost of current outlays plus the expected future recourse costs is minimized. Realistic aspects of optical networking such as network survivability based on shared spare capacity and the modularity and economy-of-scale effects are considered. These are not only important practical details to reflect in planning, but they give the “future-proof” design problem for such networks some unique aspects. For instance, what is the working capacity under one future scenario that may not waste capacity if that demand scenario does not materialize, because the same channels may be used as shared spare capacity under other future scenarios. Similarly economy-of-scale effects bear uniquely on the future-proof planning problem, as the least-cost strategy on a life-cycle basis may actually be to place more capacity today than current requirements would suggest. This is of obvious relevance to planners given the recent hard times in the telecommunications industry, causing a tendency to minimize costs now regardless of the consequences.     

Development and field trial evaluation of a new reverse osmosis module system

A 23 m³/day reverse osmosis pilot plant was installed at Appleby Parva in May 1969 and has been operated on two borehole waters. Initially, this plant contained prototype modules with membranes cast on the outside of tubes, the design of which is described in the paper. Over 3 million module hours of operation have been achieved and the satisfactory performance of both membranes and membrane supports has confirmed that the principle of a membrane cast on the outside of a suitable tubular support is sound.This led to the design of the “spaghetti” module system which is described and which is available commercially. Operating experience with these modules has nearly reached 2 million module hours on a number of brackish waters and on secondary sewage effluent. These field trials are summarised and the current performance of modules is indicated.