Thresholding is an important technique for image segmentation and object extraction. The aim of an effective segmentation is to separate objects from the background and to differentiate pixels having nearby values for improving the... more
Thresholding is an important technique for image segmentation and object extraction. The aim of an effective segmentation is to separate objects from the background and to differentiate pixels having nearby values for improving the contrast. The use of binary images reduces the ...
Google, Amazon, and other services store data in multiple geographically separated disks called nodes, among other reasons, to safeguard the data from node failures. Standard techniques for such a distributed way of storage include... more
Google, Amazon, and other services store data in multiple geographically separated disks called nodes, among other reasons, to safeguard the data from node failures. Standard techniques for such a distributed way of storage include multiple backups (typically triple replication) or using erasure codes such as Reed-Solomon codes. The latter codes are the most space-efficient for a targeted worst-case number of simultaneous node failures. They are extremely inefficient however for repairing the frequently occurring single node failure. Replication provides the most cost-effective repair in this scenario but ultimately is an unwise option in today’s data proliferation. New erasure codes are therefore required to simultaneously optimize storage efficiency, worst-case resilience and repair costs for single node failures. This dissertation looks at two such erasure codes: regenerating codes, which optimize the communication costs, and locally repairable codes (LRCs), which optimize the I/...
