A new measure for evaluating shielding performance of an equipment enclosure at frequencies above 1 GHz

The measure of shielding effectiveness (SE) and the related measurement techniques proposed by the current IEEE Standard 299 are only applicable for large screened enclosures having dimensions more than 2 m. To propose reasonable measures to assess the shielding performance of an equipment enclosure, together with the relevant measurement techniques, is the subject of this thesis. This work is informing the new developments in IEEE Standard 299. To coincide with the practical applications of most equipment enclosures, two measurement approaches distinguished by the location of the radiation source are considered in this thesis, and the measurement is performed in the radiating nearfield with test frequencies above 1 GHz. The contents inside the enclosure are stressed and involved in all the measurements. In the first measurement approach, to measure the enclosure’s ability to prevent the electromagnetic waves of internal contents from radiating outside to cause interference with nearby equipments, an emission source is -placed inside the enclosure and a receive antenna is placed outsic’j. A new measure shielding of radiating power (SRP) is proposed here, which consists of two parameters: the average shielding of radiating power (ASRP) and the enhancement factor E.F.g5lh. Two measurement environments: anechoic chamber and reverberation chamber are considered and compared. To avoid the huge measurement work in an anechoic chamber, the reverberation chamber is proposed as an ideal test environment to determine the ASRP, and the estimation of the enhancement factor E.F.gnh can be given directly based on statistic analyses on both measurement and simulation results. In the second measurement approach, to measure the enclosure’s ability to shield the internal contents against external interference, the enclosure is placed in a small reverberation chamber and illuminated by external electromagnetic field. Another new measure shielding of absorption cross section (SACS) is proposed here. However, measurement results indicate this measure has distinct advantages and disadvantages, so it is suggested prudently. Finally the first measure is proposed and reverberation chamber is suggested as the ideal test environment

Immersion on the Edge: A Cooperative Framework for Mobile Immersive Computing

Immersive computing (IC) technologies such as virtual reality and augmented reality are gaining tremendous popularity. In this poster, we present CoIC, a Cooperative framework for mobile Immersive Computing. The design of CoIC is based on a key insight that IC tasks among different applications or users might be similar or redundant. CoIC enhances the performance of mobile IC applications by caching and sharing computation-intensive IC results on the edge. Our preliminary evaluation results on an AR application show that CoIC can reduce the recognition and rendering latency by up to 52.28% and 75.86% respectively on current mobile devices.Comment: This poster has been accepted by the SIGCOMM in June 201

Could Zc(4025)Z_{c}(4025) be a JP=1+J^{P}=1^{+} D∗D∗ˉD^{*}\bar{D^{*}} molecular state?

We investigate whether the newly observed narrow resonance $Z_{c}(4025)$ can be described as a $D^{*}\bar{D^{*}}$ molecular state with quantum numbers $J^{P}=1^{+}$. Using QCD sum rules, we consider contributions up to dimension six in the operator product expansion and work at leading order of $\alpha_{s}$. The mass obtained for this state is (4.05\pm 0.28) \mbox{GeV}. It is concluded that $D^{*}\bar{D^{*}}$ molecular state is a possible candidate for $Z_{c}(4025)$.Comment: 7 pages, 4 figures.Published in Eur.Phys.J. C73 (2013) 2661. arXiv admin note: text overlap with arXiv:1304.185