Tingting Zhang

In a typical sensor network, nodes around the sink consume more energy than those further away. It is not unusual that limited energy resources available at the nodes around the sink become the bottleneck which confines the performance of the whole network. In this letter, we firstly present our considered bottleneck zone in a general sensor network scenario. Then, the effect of the bottleneck zone on network performance is investigated by deducing performance bounds imposed by the energy resources available inside the bottleneck zone. In this letter, both the performance bound in terms of network lifetime and the performance bound in terms of information collection are explored. Finally, the ways by which network deployment variables may affect the performance bounds are analyzed.

For the first time, a validated high-performance liquid chromatographic method with diode-array detection has been developed for discrimination and quality assessment of three species of Baishouwu. LC with gradient elution was performed on extracts from 23 plant samples collected from different geographic locations. The fingerprint was established and 26 chromatographic peaks were selected as characteristic peaks. Similarities of chromatograms were greater than 0.9 for the same species but much lower than 0.6 for different species. Three bioactive constituents were simultaneously analyzed for further quantitative assessment of the quality of Baishouwu, and amounts of the three analytes in different species of Baishouwu samples were found to be significantly different. This LC–DAD method is thus a very reliable and useful method for assessment of the quality of Baishouwu.

Researches around wireless sensor network (WSN) were very proliflc recently. However, tra-c modeling related WSN re- search was poorly less. In this paper, source tra-c dynamics in a simulated target tracking WSN scenario are explored. We flnd the source tra-c arrival process doesn't follow the usually considered Poisson model. Instead, an ON/OFF model is found to be capable of capturing

Wireless sensor networks are usually deployed in a way “once deployed, never changed”. The actions of sensor nodes are either pre-scheduled inside chips or triggered to respond outside events in the predefined way. This relatively predictable working flow make it easy to ...

In this paper we present a novel idea regarding transmission of next generation IPTV content. Today IPTV systems utilize a COP structure tu provide stream synchronization points for the clients, these are used when a channel switch occur. Since channel switches ...

To efficiently combat the signal loss of MPEG-2 transmission over unreliable networks, priority encoding transmission, unequal packet loss protection and priority dropping techniques have been studied in many papers. Those studies are based on the qualitative analysis of ...

In this paper, a novel proposal regarding the transmission of the next generation of live-TV content in an IPTV environment is presented. Today live-TV IP transmission systems utilizes a Group Of Pictures (GOP) structure in order to provide stream synchronization points for the clients. Synchronization points are used when a TV-channel switch occurs. The number of channel switches made by TV audiences have been shown to be rather rare. It is therefore redundant to send synchronization events in a GOP manner. Our proposal, Synchronization Frames for Channel Switching (SFCS), only requests synchronization points when required. Due to channel popularity distributions and the number of connected users, the total number of synchronization requests for a popular channel can increase to a level that makes SFCS less effective than GOP. Therefore, we introduce an SFCS-GOP hybrid. A complete network traffic analysis model, verified by a simple simulation environment, is also presented and the results show that the SFCS-GOP hybrid significantly increases the bandwidth utilization compared to a traditional GOP system

Phosphoinositide 3-kinases (PI3K) regulate immune activation via their roles in signal transduction of multiple classes of receptors. Here, we examined the effect of genetic inactivation of the hemopoietic cell-restricted PI3K isoform p110δ on systemic cytokine and chemokine responses and allergic airway inflammation. We found that type 2 cytokine responses (IL-4, IL-5 and IL-13) are significantly decreased in p110δ mutants, whereas type 1 cytokine responses (IFN-γ and CXCL10) were robust. Elevated IFN-γ production during the primary response to ovalbumin (OVA) was associated with reduced production of the regulatory cytokine IL-10. IFN-γ and IL-10 production normalized after secondary OVA immunization; however, type 2 cytokine production was persistently reduced. Type 2 cytokine-dependent airway inflammation elicited by intranasal challenge with OVA was dramatically reduced, with reduced levels of eosinophil recruitment and mucus production observed in the lungs. Induction of respiratory hyper-responsiveness to inhaled methacholine, a hallmark of asthma, was markedly attenuated in p110δ-inactivated mice. Adoptive transfer of OVA-primed splenocytes from normal but not p110δ-inactivated mice could induce airway eosinophilia in naive, airway-challenged recipient mice. These data demonstrate a novel functional role for p110δ signaling in induction of type 2 responses in vivo and may offer a new therapeutic target for Th2-mediated airway disease.