Guest Editorial: Green and Cloud Computing

Energy consumption is a bottleneck for information computing and communication. Green computing aims to reduce energy costs as well as to effectively reuse and recycle power usage. The topics include energy-efficient CPUs, memories, clusters, data centers, and peripherals as well as reduced resource consumption. The emerging cloud computing provides a new way to address the constraints of limited energy, capabilities, and resources. Cloud computing is the second focus of this special issue. Five papers have been accepted from an open call, and they are briefly discussed as follows. First, “Optimizing Data Placement of Loops for Energy Minimization with Multiple Types of Memories”, by Zhuge et al. (10.1007/s11265-013-0774-y), studies the problem of how to optimally place array data in loops to multiple types of memory units such that the energy and time costs of memory accesses can be minimized and proposes several novel algorithms to solve the problem. For green computing, storage system is an important area. The paper “Eco-Storage: A Hybrid Storage System with Energy-Efficient Informed Prefetching”, by Maen Al Assaf et al. (10.1007/s11265-013-0784-9), presents a power-aware informed prefetching technique that makes use of the application-disclosed access patterns to group the informed prefetching process in a hybrid storage system with hard drives (HDDs) and solid state disks (SSDs). Simulation results show significant reduction of power consumption through this approach. In another paper “Thermal Modeling of Hybrid Storage Clusters” (10.1007/s11265-013-0787-6), the authors propose a thermal model for hybrid storage clusters that are comprised of HDDs and SSDs, and develop a model to estimate cooling cost of a storage cluster equipped with hybrid storage nodes. Power-aware computing is critical in wireless sensor networks. In the paper “BER-based Power Scheduling in Wireless Sensor Networks” (10.1007/s11265-0130776-9), the authors investigate the Bit Error Rate (BER) during packet transmission and propose a power scheduling scheme to reduce the total energy consumption in the routing. The proposed approach controls the transmission power of each transmitter to achieve the minimum energy consumption for successful packet transmission. For cloud computing, the paper entitled “SAFE: A Source Deduplication Framework for Efficient Cloud Backup Services”, by Yujuan Tan et al. (10.1007/s11265-013-0775-x), proposes a source deduplication framework for efficient cloud backup and restore operations. The framework has three features: hybrid deduplication, semantic-aware Elimination, and unmodified data removal. Experiments show this approach can shorten the backup time by an average of 38.7 %, and reduce the restore time by a ratio of up to 9.7 : 1. In this special issue, based on the strict peer-reviewed process, we selected five outstanding papers covering a wide range green and cloud computing. These papers provide frontier information with current depth and breadth of green and cloud computing research. M. Qiu (*) San Jose State University, San Jose, CA, USA e-mail: qiumeikang@yahoo.com