Yen-Chieh Ouyang

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Cloud computing is a new paradigm for delivering remote computing resources through a network. However, achieving an energy-efficiency control and simultaneously satisfying a performance guarantee have become critical issues for cloud providers. In this paper, three power-saving policies are implemented in cloud systems to mitigate server idle power. The(More)
Security and energy efficiency are the most important concerns in wireless sensor networks (WSNs) design. To save the power and extend the lifetime of WSNs, various media access control (MAC) protocols are proposed. Most traditional security solutions can not be applied in the WSNs due to the limitation of power supply. The well-known security mechanisms(More)
The Adaptive Inverse Hyperbolic Tangent (AIHT) algorithm is capable of enhancing the global contrast of the original image adaptively, while extruding the details of objects simultaneously, cannot enhance local contrast. Therefore, we proposed a ContrastLimited Adaptive Histogram Equalization (CLAHE) modulation based on AIHT contrast enhancement algorithm(More)
This paper presents a decentralized clustering and gateway selection algorithm for wireless ad-hoc sensor networks. Each sensor uses a random waiting timer and local criteria to determine whether to form a new cluster or to join a current cluster and utilizes the messages transmitted during hierarchical clustering to choose distributed gateways such that(More)
This paper presents a secure decentralized clustering algorithm for wireless ad-hoc sensor networks. The algorithm operates without a centralized controller, operates asynchronously, and does not require that the location of the sensors be known a priori. Based on the cluster-based topology, secure hierarchical communication protocols and dynamic quarantine(More)
PURPOSE To effectively perform quantification of brain normal tissues and pathologies simultaneously, independent component analysis (ICA) coupled with support vector machine (SVM) is investigated and evaluated for effective volumetric measurements of normal and lesion tissues using multispectral MR images. MATERIALS AND METHODS Synthetic and real MR data(More)