Pyramid scheme

Debbie Herridge unwraps the mummy of ‘topic work’ and discovers a wealth of practical science experiments within...

The Visual Secret Sharing Scheme Based on the Rgb Color System

The visual secret sharing (VSS) scheme is a method to maintain the confidentiality of a se-cret image by sharing it to some number participants. A (k, n) VSS divides the secret images into n parts, that are called shadows ; to recover the secret back, k shadows should be stacked. Some methods have been developed to implement VSS for color images. However, the methods are only suitable for images with limited number of colors. When more colors are used, the resulted stacked shadow image becomes unclear. Besides that, the size of the shadows becomes bigger as more colors are used. We develop a new method implementing the VSS using the RGB color system. Using our method, the problem related to the unclear stacked shadow image can be overcome

A microwave dielectric biosensor based on suspended distributed MEMS transmission lines

Design and characterization of a miniature microwave dielectric biosensor based on distributed microelectromechanical systems (MEMS) transmission lines (DMTL) is reported in this paper. The biosensor has been realized by bonding the DMTL device with an acrylic fluidic channel. In order to demonstrate the sensing mechanism, the sensor is used to detect the small variation of the concentration of aqueous glucose solutions by measuring the electromagnetic resonant frequency shift of the device. It is observed from the results that the second notch of the reflection coefficient (S-11) varies from 7.66 to 7.93 GHz and the third notch of the reflection coefficient varies from 15.81 to 15.24 GHz when the concentration of the glucose solution ranges from 0 to 347 mg/ml, which indicates that higher order notches have higher sensitivities if looking at the absolute change in frequency

Population-based incremental learning with memory scheme for changing environments

Copyright @ 2005 ACMIn recent years there has been a growing interest in studying evolutionary algorithms for dynamic optimization problems due to its importance in real world applications. Several approaches have been developed, such as the memory scheme. This paper investigates the application of the memory scheme for population-based incremental learning (PBIL) algorithms, a class of evolutionary algorithms, for dynamic optimization problems. A PBIL-specific memory scheme is proposed to improve its adaptability in dynamic environments. In this memory scheme the working probability vector is stored together with the best sample it creates in the memory and is used to reactivate old environments when change occurs. Experimental study based on a series of dynamic environments shows the efficiency of the memory scheme for PBILs in dynamic environments. In this paper, the relationship between the memory scheme and the multipopulation scheme for PBILs in dynamic environments is also investigated. The experimental results indicate a negative interaction of the multi-population scheme on the memory scheme for PBILs in the dynamic test environments

65+ Membership Scheme

This report shares the journey of three partners' experiment with digital technology to address societal challenges linked to ageing and social isolation. In recent years artsdepot has seen enormous changes to its business model driven by the advance of digital communication tools, rapidly increasing use of social media, and changing consumer behaviours. The project team felt that digital innovation was typically aimed at the young but wondered if there was greater potential to increase attendance and sales while also addressing social isolation through creating digital innovations with older people. A range of partners worked on the project: artsdepot (arts partner and project lead) is a multi-art form venue based in North Finchley welcoming 130,000 audience members annually. DigiLab (research partner) is an R&D laboratory based at London College of Communication, University of the Arts London. Ingelby (tech partner) is a digital agency specialising in app building and mobile app development, as well as mobile website design , e-commerce development , customised CRM systems and creative digital media. This project aimed to explore digital technologies that could help create increased levels of arts attendance among older people by identifying barriers and designing digital solutions. artsdepot felt that by enabling increased arts attendance and therefore facilitating opportunities to socialise, they might help establish new friendships while providing enriching creative experiences. Additionally, the team felt there was an additional benefit in terms of demonstrating an economic model for engaging older audiences. Having learnt in the application phase that two thirds of older people have more disposable income than any other age group, artsdepot felt that if it could address other barriers to attendance, it could also improve ticket sales and build a case for increased focus on older audiences

Exploiting Regional Differences: A Spatially Adaptive Random Access

In this paper, we discuss the potential for improvement of the simple random access scheme by utilizing local information such as the received signal-to-interference-plus-noise-ratio (SINR). We propose a spatially adaptive random access (SARA) scheme in which the transmitters in the network utilize different transmit probabilities depending on the local situation. In our proposed scheme, the transmit probability is adaptively updated by the ratio of the received SINR and the target SINR. We investigate the performance of the spatially adaptive random access scheme. For the comparison, we derive an optimal transmit probability of ALOHA random access scheme in which all transmitters use the same transmit probability. We illustrate the performance of the spatially adaptive random access scheme through simulations. We show that the performance of the proposed scheme surpasses that of the optimal ALOHA random access scheme and is comparable with the CSMA/CA scheme.Comment: 10 pages, 10 figure