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Queue-Sharing Multiple Access (QSMA) is introduced and analyzed. The new channel-access method consists of establishing and maintaining a distributed transmission queue among nodes sharing a common channel and results in a sequence of queue cycles, with each cycle having one or multiple queue turns with collision-free transmissions from nodes that have joined the transmission queue, followed by a joining period for the current cycle. Nodes can take advantage of carrier sensing to improve the efficiency with which nodes join and use the shared transmission queue. The through- put of ALOHA with priority ACK’s, CSMA with priority ACK’s, CSMA/CD with priority ACK’s, TDMA with a fixed schedule, and QSMA with and without carrier sensing is compared analytically and by simulation in ns-3. The results show that QSMA is more efficient than TDMA with the simplicity of CSMA or ALOHA. 

The Internet Transport Protocol (ITP) is introduced as an alternative to the Transmission Control Protocol (TCP) for reliable end-to-end transport services in the IP Internet. The design of ITP is based on Walden’s early work on host- host protocols, and the use of receiver-driven Interests and manifests advocated in several information-centric networking architectures. The performance of ITP is compared against the performance of TCP using off-the-shelf implementations in the ns3 simulator. The results show that ITP is inherently better than TCP and that end-to-end connections are not needed to provide efficient and reliable data exchange in the IP Internet. 

The Internet Transport Protocol (ITP) is introduced to support reliable end-to-end transport services in the IP Internet without the need for end-to-end connections, changes to the Internet routing infrastructure, or modifications to name-resolution services. Results from simulation experiments show that ITP outperforms the Transmission Control Protocol (TCP) and the Named Data Networking (NDN) architecture, which requires replacing the Internet Protocol (IP). In addition, ITP allows transparent content caching while enforcing privacy. 

Named-Data Transport (NDT) is introduced to provide efficient content delivery by name over the existing IP Internet. NDT consists of the integration of three end-to-end architectural components: The first connection-free reliable transport protocol, the Named-Data Transport Protocol (NDTP); minor extensions to the Domain Name System (DNS) to include records containing manifests describing content; and transparent caches that track pending requests for content. NDT uses receiver-driven requests (Interests) to request content and NDT proxies that provide transparent caching of content while enforcing privacy. The performance of NDT, the Transmission Control Protocol (TCP), and Named-Data Networking (NDN) is compared using off-the-shelf implementations in the ns-3 simulator. The results demonstrate that NDT outperforms TCP and is as efficient as NDN, but without making any changes to the existing Internet routing infrastructure. 

We present an algorithm for perfectly uniform sampling of satisfying assignments, based on the exact model counter sharpSAT and reservoir sampling. In experiments across several hundred formulas, our sampler is faster than the state of the art by 10 to over 100,000 times. 

We present a probabilistic model counter that can trade off running time with approximation accuracy. As in several previous works, the number of models of a formula is estimated by adding random parity constraints (equations). One key difference with prior works is that the systems of parity equations used correspond to the parity check matrices of Low Density Parity Check (LDPC) error-correcting codes. As a result, the equations tend to be much shorter, often containing fewer than 10 variables each, making the search for models that also satisfy the parity constraints far more tractable. The price paid for computational tractability is that the statistical properties of the basic estimator are not as good as when longer constraints are used. We show how one can deal with this issue and derive rigorous approximation guarantees by performing more solver invocations.