Zhichao Zhao

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Motivated by online advertisement and exchange settings, greedy randomized algorithms for the maximum matching problem have been studied, in which the algorithm makes (random) decisions that are essentially oblivious to the input graph. Any greedy algorithm can achieve performance ratio 0.5, which is the expected number of matched nodes to the number of(More)
Bitcoin is the first decentralized crypto-currency that is currently by far the most popular one in use. The bitcoin transaction syntax is expressive enough to setup digital contracts whose fund transfer can be enforced automatically. In this paper, we design protocols for the bitcoin voting problem, in which there are n voters, each of which wishes to fund(More)
The past several years have seen tremendous advances in practical, general-purpose, noninteractive proof systems called SNARKs. These building blocks are efficient and convenient, with multiple publicly available implementations, including tools to compile high-level code (e.g., written in C) to arithmetic circuits, the native representation used by SNARK(More)
Non-interactive zero-knowledge proofs are a powerful cryptographic primitive used in privacypreserving protocols. We design and build C∅C∅, the first system enabling developers to build efficient, composable, non-interactive zero-knowledge proofs for generic, user-defined statements. C∅C∅ extends state-of-the-art SNARK constructions by applying known(More)
The principle of energy-saving in hydraulic hybrid vehicles was introduced. The characteristics of hybrid vehicles with electric or hydraulic were compared. Because of its higher power density and higher efficiency, hydraulic hybrid vehicle is more advantageous when working under the condition changed frequently such as city bus. Different arrangement forms(More)
We consider the Minimum Independent Set Partition Problem (MISP) and its dual (MISPDual). The input is a multi-set of N vectors from {0, 1}, where U := {1, . . . , n} is the index set. In MISP, a threshold k is given and the goal is to partition U into a minimum number of subsets such that the projected vectors on each subset of indices has multiplicity at(More)
Given a rooted tree with n nodes, the tree shortcut problem is to add a set of shortcut edges to the tree such that the shortest path from each node to any of its ancestors is of length O(logn) and the degree increment of each node is constant. We consider in this paper the dynamic version of the problem, which supports node insertion and deletion. For(More)
A new data fusion method called joint probability density matrix (JPDM) is proposed, which can associate and fuse measurements from spatially distributed heterogeneous sensors to identify the real target in a surveillance region. Using the probabilistic grids representation, we numerically combine the uncertainty regions of all the measurements in a general(More)