Diode-switched thermal-transfer printed antenna on flexible substrate

We demonstrate that diode-switching can be used to introduce frequency agility into antennas produced by thermal transfer printing. Our particular example is a triangular Sierpinski fractal pattern with two PIN diodes to switch between operation optimised for the 800 MHz UHF band (diodes on) and the 2400 MHz ISM band (diodes off). Our measured results show an improvement in S11 in the UHF band from -2 dB to -28 dB, and from -7 dB to -30 dB at 2400 MHz, when switching the diodes appropriately. The measured bandwidth is 200 (1000) MHz, and the measured directivity is 3.1dB (5.2dB) while the measured gain is -5.2dB (6.7dB) for the diodes on(off)

Optimized consortium formation through cluster analysis

Some problems cannot be solved optimally and compromises become necessary. In some cases obtaining an optimal solution may require combining algorithms and iterations. This often occurs when the problem is complex and a single procedure does not reach optimality. This paper shows a conglomerate of algorithms iterated in tasks to form an optimal consortium using cluster analysis. Hierarchical methods and distance measures lead the process. Few companies are desirable in optimal consortium formation. However, this study shows that optimization cannot be predetermined based on a specific fixed number of companies. The experiential exercise forms an optimal consortium of four companies from six shortlisted competitor

Running Again

Efforts to reduce peak electrical demand have led to the introduction of demand response (DR) programmes for residences. DR programmes allow customers to reduce or shift consumption to off-peak periods in response to price signals. The RDS network is a strong candidate for delivering DR messages due to its low-cost nature and ubiquitous coverage. However, security concerns arise due to the wireless nature of the communication channel.We present evaluations of three candidate cryptographic methods that could be employed to offer source authentication over the RDS network: BiBa, HORSE and elliptic curve digital signature algorithm (ECDSA).We compare the security offered by the protocols, the bandwidth overhead, computational costs and message reception probability. Simulation results show that, up to a distance of 90 km, all authentication schemes do not affect message reception by the receivers. Beyond that, all the schemes have an effect on message reception due to increased message sizes and receiver bootstrapping for BiBa and HORSE. ECDSA and HORSE outperform BiBa in terms of message reception beyond 90 km. ECDSA, however, offers higher security than HORSE and BiBa but at the cost of increased computational complexity, in particular, at the receivers. In addition, has the highest bandwidth overhead. Copyrigh