Public cloud storage can provide customers with unlimited capacity and built-in disaster recovery by exploiting IT resources in data center but suffers high latency and security risk. The emergency of fog computing can mitigate data security risk by leveraging local private server with low latency. We introduce F2MC: a Fog-to-MultiCloud hybrid storage service that combines local fog computing with remote cloud computing to enhance the quality of service (QoS) of data management. It provides an application aware data reduction scheme to improve the data traffic and space efficiency of cloud storage by exploiting deduplication and compression. Then, it further enhances the resiliency and security of cloud storage by striping encrypted data across multiple cloud vendors with a secure fault-tolerant coding. Compared with the state-of-the-art of multicloud storage systems, our experiments demonstrate that F2MC can achieve the highest performance with the same fault-tolerance capability, and a competitive low cloud cost due to its low cloud storage space overheads.

The end-to-end network services often requires various Network Functions (NFs) that provides the L4-L7 functionality. Service Function Chaining (SFC), which consists of an ordered set of NFs, and Software Defined Network (SDN), which has global view of the network and programmability, easily enable the creation of network services. However, the underlying network forwarding behaviors may be not compliant with the SFC policies. In this paper, we analyze the fundamental cause of the incompliance and propose an algorithm to check the enforcement of SFC policies. Modules and structure to implement and integrate the algorithm to a SDN network is provided. Effectiveness and performance is demonstrated in Mininet as well as a test SDN network on campus.

We propose a novel approach to generate 4D light field in the physical world for lighting reproduction. The light field is generated by projecting lighting images on a lens array. The lens array turns the projected images into a controlled anisotropic point light source array which can simulate the light field of a real scene. In terms of acquisition, we capture an array of light probe images from a real scene, based on which an incident light field is generated. The lens array and the projectors are geometric and photometrically calibrated, and an efficient resampling algorithm is developed to turn the incident light field into the images projected onto the lens array. The reproduced illumination, which allows per-ray lighting control, can produce realistic lighting result on real objects, avoiding the complex process of geometric and material modeling. We demonstrate the effectiveness of our approach with a prototype setup.

Botnets have contributed to the significant part of the increasing malicious activities such as Distributed Denial of Service (DDoS), spam, and click fraud. Based on the analysis on the basic and essential characters of botnet, this paper deals with the botnet in two aspects: formal definition and general framework, covering various types of botnets overall. Through the formal definition and the general framework, the essential components of the botnet (i.e. botmaster, Command and Control mechanism, and bots) are described in detail and the features of the vital Command and Control (C&C) mechanism are augmented. The formal definition for botnet, to the best of our knowledge, is first proposed and the general framework, analyzed in some case studies, is not only helpful to interpret the existing botnets in the real world, but also beneficial to the implement of the potential botnets in the future.

DHT (Distributed Hash Table) algorithms are very efficient for distributed data storage and retrieval. As one kind of P2P overlay, DHT overlay also has the advantages of high reliability, high scalability and low cost. DHT has not only been applied to form user nodes' overlays, but also been proposed to form DHT-based server farms, such as DHT-based SIP server farm, HSS server farm, DNS server farm, CDN server farm, etc. However, seldom DHT algorithms consider server farm's stringent requirement on system capacity, and only a handful of DHT algorithms take server into consideration. This paper presents our DHT algorithm called SFDHT for high throughput DHT server farm. Compared with existing DHTs, SFDHT considers the characters and requirements of DHT server farm and maximizes system capacity. SFDHT is a one-hop DHT with novel built-in load balancing solution. The proposed load balancing solution produces much less overhead that existing solutions do. Both theoretical analysis and simulation results show that SFDHT can reduce overhead, balance load and improve system capacity.