Talk More Listen Less: Energy-Efficient Neighbor Discovery in Wireless Sensor Networks

Neighbor discovery is a fundamental service for initialization and managing network dynamics in wireless sensor networks and mobile sensing applications. In this paper, we present a novel design principle named Talk More Listen Less (TMLL) to reduce idle-listening in neighbor discovery protocols by learning the fact that more beacons lead to fewer wakeups. We propose an extended neighbor discovery model for analyzing wakeup schedules in which beacons are not necessarily placed in the wakeup slots. Furthermore, we are the first to consider channel occupancy rate in discovery protocols by introducing a new metric to trade off among duty-cycle, latency and channel occupancy rate. Guided by the TMLL principle, we have designed Nihao, a family of energy-efficient asynchronous neighbor discovery protocols for symmetric and asymmetric cases. We compared Nihao with existing state of the art protocols via analysis and real-world testbed experiments. The result shows that Nihao significantly outperforms the others both in theory and practice.Comment: 9 pages, 14 figures, published in IEEE INFOCOM 201

Flexible coherent control of plasmonic spin-Hall effect

The surface plasmon polariton is an emerging candidate for miniaturizing optoelectronic circuits. Recent demonstrations of polarization-dependent splitting using metasurfaces, including focal-spot shifting and unidirectional propagation, allow us to exploit the spin degree of freedom in plasmonics. However, further progress has been hampered by the inability to generate more complicated and independent surface plasmon profiles for two incident spins, which work coherently together for more flexible and tunable functionalities. Here by matching the geometric phases of the nano-slots on silver to specific superimpositions of the inward and outward surface plasmon profiles for the two spins, arbitrary spin-dependent orbitals can be generated in a slot-free region. Furthermore, motion pictures with a series of picture frames can be assembled and played by varying the linear polarization angle of incident light. This spin-enabled control of orbitals is potentially useful for tip-free near-field scanning microscopy, holographic data storage, tunable plasmonic tweezers, and integrated optical components

Network pharma cology and GEO chip based elucidation of mechanisms underlying the use of Yi Tieqing for prevention and treatment of postoperative nausea and vomiting

Purpose: To investigate the mechanism(s) involved in the use of Yi Tieqing for the prevention and treatment of postoperative nausea and vomiting (PONV), using network pharmacology and GEO chip. Methods: The chemical constituents and functional targets of five traditional Chinese medicines in Yi Tieqing were obtained by searching TCMSP database. The PONV disease targets were identified through DisGeNET, GeneCards and DrugBank databases, and differential expression genes of the GEO database chip (GSE7762) were mined. From the intersections of the component targets and disease targets, the core targets of drugs and diseases were obtained. The core targets were investigated in R language using GO-biological process and KEGG enrichment analyses, and their biological activities were verified via molecular docking. Finally, the severity and incidence of PONV in control and treatment groups were determined and compared. Results: A total of 254 bioactive components and 301 related potential targets were obtained from the TCMSP database. There were 2092 related targets in PONV, and 6 intersecting targets were obtained from Venn diagram. The results of GO biological process and KEGG enrichment analysis showed that the incidence of PONV was strongly correlated with the negative regulation of response to wounding and nervous system. Clinical results showed that from 24 – 48 h (T2) after operation, the severity and incidence of PONV in the treatment group were significantly lower than those in the control group (p < 0.05). Conclusion: Yi Tieqing alleviates PONV through multi-components, multi-targets, and multi-pathways