The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Temkar N Ruckmongathan - One of the best experts on this subject based on the ideXlab platform.

David M Fisher - One of the best experts on this subject based on the ideXlab platform.

David P Williamson - One of the best experts on this subject based on the ideXlab platform.

  • a general Approximation Technique for constrained forest problems
    Symposium on Discrete Algorithms, 1992
    Co-Authors: Michel X Goemans, David P Williamson
    Abstract:

    We present a general Approximation Technique for a large class of graph problems. Our Technique mostly applies to problems of covering, at minimum cost, the vertices of a graph with trees, cycles or paths satisfying certain requirements. In particular, many basic combinatorial optimization problems fit in this framework, including the shortest path, minimum spanning tree, minimum-weight perfect matching, traveling salesman and Steiner tree problems.Our Technique produces Approximation algorithms that run in O(n2 log n) time and come within a factor of 2 of optimal for most of these problems. For instance, we obtain a 2-Approximation algorithm for the minimum-weight perfect matching problem under the triangle inequality. Our running time of O(n2 log n) time compares favorably with the best strongly polynomial exact algorithms running in O(n3) time for dense graphs. A similar result is obtained for the 2-matching problem and its variants.We also derive the first Approximation algorithms for many NP-complete problems, including the non-fixed point-to-point connection problem, the exact path partitioning problem and complex location-design problems. Moreover, for the prize-collecting traveling salesman or Steiner tree problems, we obtain 2-Approximation algorithms, therefore improving the previously best-known performance guarantees of 2.5 and 3, respectively [4].

Martin Branda - One of the best experts on this subject based on the ideXlab platform.

Xinquan Lai - One of the best experts on this subject based on the ideXlab platform.

  • oversampling successive Approximation Technique for mems differential capacitive sensor
    IEEE Journal of Solid-state Circuits, 2018
    Co-Authors: Longjie Zhong, Xinquan Lai
    Abstract:

    This paper proposed an oversampling successive Approximation (OSSA) Technique to build switched-capacitor capacitance-to-voltage convertor (SC-CVC) for readout circuit of MEMS differential capacitive sensor. The readout circuit employing the OSSA Technique has significantly improved resistance to common-mode parasitic capacitance of the input terminal of the readout circuit. In the OSSA readout circuit, there are five main non-ideal characteristics: holding error, recovery degradation, increment degradation, rise-edge degradation, and charge injection which reduce the accuracy and the settling time of the circuit. These problems are explained in detail and their solutions are given in this paper. The OSSA readout circuit is fabricated in a commercial 0.18- $\mu \text{m}$ BCD process. To show the improvement evidently, a reported traditional readout circuit is also reproduced and fabricated using the same process. Compared with the traditional readout circuit, the proposed readout circuit reduces the effect of common-mode parasitic capacitance on the accuracy of SC-CVC by more than 23.8 dB, power dissipation by 69.3%, and die area by 50%.

  • Differential Capacitive Readout Circuit Using Oversampling Successive Approximation Technique
    IEEE Transactions on Circuits and Systems I: Regular Papers, 2018
    Co-Authors: Longjie Zhong, Xinquan Lai, Hongjiang Song
    Abstract:

    This paper designs a close loop $\Sigma - \Delta $ readout circuit for differential MEMS accelerometer. A Technique named oversampling successive Approximation (OSA) is employed to build basic amplifiers and integrators. This Technique can largely reduce the gain error and thus low gain amplifier such as single stage amplifier is allowed to be used. As a result, the power consumption and chip area are reduced. However, the OSA-based amplifiers and integrators are vulnerable to the interference caused by charge injection and leakage current from the specific MOSFET switches. This drawback is analyzed in detail and the interference suppressing solutions are given. The OSA-based readout circuit is fabricated in a commercial 0.18 $\mu \text{m}$ BCD process. The measurement results show that the interference is reduced by 20 dB in the circuit with interference suppressing solutions compared with the circuit without interference suppressing solutions. And the noise floor is 24 $\mu \text{g}$ /rtHz. The readout circuit achieves a 0.07% gain error with a low power consumption of 0.5 mW and 9 MHz sampling rate.