In the past Shaojie Tang has collaborated on articles with Xiang-Yang Li and Yunxia Feng. One of their most recent publications is Original research articleThe effect of interpolation functions on CT reconstruction. Which was published in journal Optik.

More information about Shaojie Tang research including statistics on their citations can be found on their Copernicus Academic profile page.

Shaojie Tang's Articles: (5)

Original research articleThe effect of interpolation functions on CT reconstruction

AbstractAn approach was proposed for studying the effect of interpolation function on CT reconstruction, which could be utilized in both the assessment and the optimization of interpolation function. The underlying principle was based on a direct analysis of the numerical implementation of CT reconstruction algorithm. According to the theoretical and simulated results, we observed that different interpolation function really demonstrates different performance.

Mechanism design for set cover games with selfish element agentsā˜†

AbstractIn this article, we study the set cover games when the elements are selfish agents, each of which has a privately known valuation of receiving the service from the sets, i.e., being covered by some set. Each set is assumed to have a fixed cost. We develop several approximately efficient strategyproof mechanisms that decide, after soliciting the declared bids by all elements, which elements will be covered, which sets will provide the coverage to these selected elements, and how much each element will be charged. For single-cover set cover games, we present a mechanism that is at least 1dmax-efficient, i.e., the total valuation of all selected elements is at least 1dmax fraction of the total valuation produced by any mechanism. Here, dmax is the maximum size of the sets. For multi-cover set cover games, we present a budget-balanced strategyproof mechanism that is 1dmaxHdmax-efficient under reasonable assumptions. Here, Hn is the harmonic function. For the set cover games when both sets and elements are selfish agents, we show that a cross-monotonic payment-sharing scheme does not necessarily induce a strategyproof mechanism.

Fault Tolerant Data Aggregation Scheduling with Local Information in Wireless Sensor Networks*

AbstractWe study the problem of efficient data aggregation in unreliable wireless sensor networks by designing a fault tolerant data aggregation protocol. A fault tolerant data aggregation protocol consists of two parts: basic aggregation scheduling and amendment strategies. On default, data is aggregated according to the basic aggregation scheduling strategy. The amendment strategy will start automatically when a middle sensor node is out of service. We focus our attention on the amendment strategies and assume that the network adopts a connected dominating set (CDS) based aggregation scheduling as its basic aggregation scheduling strategy. The amendment scheme includes localized aggregation tree repairing algorithms and distributed rescheduling algorithms. The former are used to find a new aggregation tree for every child of the corrupted node, whereas the latter are used to achieve interference free data aggregation scheduling after the amendment. These amendment strategies impact only a very limited number of nodes near the corrupted node and the amendment process is transparent to all the other nodes. Theoretical analyses and simulations show that the scheme greatly improves the efficiency of the data aggregation operation by reducing both message and time costs compared to rebuilding the aggregation tree and rescheduling the entire network.

RIM: Relative-importance based data forwarding in people-centric networks

AbstractThe fast penetration of mobile phones has arisen the requirement to share content (e.g., news, photo, music, video clips, etc.) among devices. To improve the efficiency of content sharing, recent works select nodes with high centrality in the system to cache and forward contents, resulting in a bias towards the most popular nodes. However, these nodes are not the appropriate candidates for target nodes, since the globally powerful nodes may have little influence on some local communities where the targets belong. Interestingly, we observe that nodes with low global centrality but high relative importance to the targets bear most weight on content allocation. Motivated by this observation, we exploit the relative importance of a node with respect to a group of nodes to guide the allocation process. We quantify the relative importance of nodes using graph spectrum theory, we then propose RIM (Relative IMportance), a novel data forwarding scheme to improve the allocation efficiency. By applying RIM on three real people-centric scenarios, the evaluation results show that RIM achieves significantly better mean delivery delay and cost than the state-of-the-art solutions, while achieving delivery ratios sufficiently close to those by Epidemic under different message TTL requirements.

EFCon: Energy flow control for sustainable wireless sensor networks

AbstractThe rapid advances in processor, memory, and radio technology enable the development of small, inexpensive sensor nodes that are capable of sensing, computation, and communication. However, the severe energy constraints of the sensors present major challenges for long-term applications. In order to achieve sustainability, environmental energy harvesting has been demonstrated as a promising approach. In this work, the energy utilization scheme is investigated for wireless sensor networks with energy harvesting nodes. The energy utilization system is divided to three parts: energy harvesting, energy consuming and energy storage. Then the sustainability problem is formulated as an energy flow control problem. An energy flow control system, called EFCon, is proposed to keep the balance between energy supplies and demands. EFCon consists of two phases, energy flow direction control and flow rate control. In the phase of energy flow direction control, the system dynamically switches among four patterns: flood flow, direct flow, compensate flow, and backup flow, according to current environmental energy condition and the residual energy condition. Once the energy flow direction is determined, a corresponding energy flow rate control strategy will be adopted for efficient energy utilization. The EFCon is implemented and validated by a long-term deployment in real testbeds. The experimental results indicate that the EFCon outperforms existing designs.

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