Privacy-preserving Cross-domain Routing Optimization -- A Cryptographic Approach

Today's large-scale enterprise networks, data center networks, and wide area networks can be decomposed into multiple administrative or geographical domains. Domains may be owned by different administrative units or organizations. Hence protecting domain information is an important concern. Existing general-purpose Secure Multi-Party Computation (SMPC) methods that preserves privacy for domains are extremely slow for cross-domain routing problems. In this paper we present PYCRO, a cryptographic protocol specifically designed for privacy-preserving cross-domain routing optimization in Software Defined Networking (SDN) environments. PYCRO provides two fundamental routing functions, policy-compliant shortest path computing and bandwidth allocation, while ensuring strong protection for the private information of domains. We rigorously prove the privacy guarantee of our protocol. We have implemented a prototype system that runs PYCRO on servers in a campus network. Experimental results using real ISP network topologies show that PYCRO is very efficient in computation and communication costs

Online Bargaining as a Form of Dynamic Pricing and the Sellers\u27 Advantage from Information Assymmetry

Among the means of implementing dynamic pricing strategies in e-commerce, online bargaining is found to be better than revenue management and online auction, because each deal actually reaches a “win-win” situation for both the buyer and the seller in the sense that the mutually agreed deal price is higher than the seller’s reserved price but lower than the buyer’s reserved price. Such feature brings profit to the seller, as well as savings to the buyer. Meanwhile when bargaining online, there is an information asymmetry between the seller side, i.e. the company side, and the buyer side, which grants a great advantage to the sellers over the buyers. This information asymmetry can be captured and exploited for financial gains through adopting a properly designed online bargaining algorithm

From M-ary Query to Bit Query: a new strategy for efficient large-scale RFID identification

The tag collision avoidance has been viewed as one of the most important research problems in RFID communications and bit tracking technology has been widely embedded in query tree (QT) based algorithms to tackle such challenge. Existing solutions show further opportunity to greatly improve the reading performance because collision queries and empty queries are not fully explored. In this paper, a bit query (BQ) strategy based Mary query tree protocol (BQMT) is presented, which can not only eliminate idle queries but also separate collided tags into many small subsets and make full use of the collided bits. To further optimize the reading performance, a modified dual prefixes matching (MDPM) mechanism is presented to allow multiple tags to respond in the same slot and thus significantly reduce the number of queries. Theoretical analysis and simulations are supplemented to validate the effectiveness of the proposed BQMT and MDPM, which outperform the existing QT-based algorithms. Also, the BQMT and MDPM can be combined to BQMDPM to improve the reading performance in system efficiency, total identification time, communication complexity and average energy cost

Effect of near-fault ground motions with long-period pulses on the tunnel

Investigations from recent strong earthquakes indicate most of the tunnels severely damaged are located near the causative faults. First, the dynamic response of the tunnel to the near-fault and far-field ground motions was investigated. The results show that the near-fault motions with long-period pulses especially the forward directivity pulses are more damaging than the typical far-field records, which should be reflected in the seismic design guideline for tunnels near causative faults. Furthermore, the effects of the key parameters for the simplified pulse on the dynamic response of the tunnel were also studied. Generally, the pulse with larger amplitude brings more energy and leads to larger strains in rock. Consequently, it becomes more damaging to the tunnel. The period of the pulse can remarkably influence the response of the tunnel. When the period of the pulse is less than 3.0 s, the pulse becomes less damaging to the tunnel with the increase of the period. Once the period exceeds 3.0 s, the pulse has little effect on the dynamic response of the tunnel. Thus, the earthquake with lower magnitude, which is likely to leads to lower period, may be more damaging to the tunnel. Besides, as the number of significant cycles increases, the damage potential of the ground motions increases accordingly. For the sake of security, two significant cycles in velocity-time history are recommended for the seismic design of tunnels close to ruptured faults