7027901
Reliable Multicast Transport Protocol (RMTP)
This paper presents the design, implementation, and performance of a reliable multicast transport protocol (RMTP). The RMTP is based on a hierarchical structure in which receivers are grouped into local regions or domains and in each domain there is a special receiver called a designated receiver (DR) which is responsible for sending acknowledgments periodically to the sender, for processing acknowledgment from receivers in its domain, and for retransmitting lost packets to the corresponding receivers. Since lost packets are recovered by local retransmissions as opposed to retransmissions from the original sender, end-to-end latency is significantly reduced, and the overall throughput is improved as well. Also, since only the DRs send their acknowledgments to the sender, instead of all receivers sending their acknowledgments to the sender, a single acknowledgment is generated per local region, and this prevents acknowledgment implosion. Receivers in RMTP send their acknowledgments to the DRs periodically, thereby simplifying error recovery. In addition, lost packets are recovered by selective repeat retransmissions, leading to improved throughput at the cost of minimal additional buffering at the receivers. This paper also describes the implementation of RMTP and its performance on the Internet.
533614
Probing TCP Implementations
In this paper, we demonstrate a technique called active probing used to study TCP implementations. Active probing treats a TCP implementation as a black box, and uses a set of procedures to probe the black box. By studying the way TCP responds to the probes, one can deduce several characteristics of the implementation. The technique is particularly useful if TCP source code is unavailable. 
 
To demonstrate the technique, the paper shows example probe procedures that examine three aspects of TCP. The results are informative: they reveal implementation flaws, protocol violations, and the details of design decisions in five vendor-supported TCP implementations. The results of our experiment suggest that active probing can be used to test TCP implementations.
8597170
Approximations to magic: finding unusual medical time series
In this work we introduce the new problem of finding time series discords. Time series discords are subsequences of longer time series that are maximally different to all the rest of the time series subsequences. They thus capture the sense of the most unusual subsequence within a time series. While the brute force algorithm to discover time series discords is quadratic in the length of the time series, we show a simple algorithm that is 3 to 4 orders of magnitude faster than brute force, while guaranteed to produce identical results.
16344930
The role of knowledge in conceptual retrieval: a study in the domain of clinical medicine
Despite its intuitive appeal, the hypothesis that retrieval at the level of "concepts" should outperform purely term-based approaches remains unverified empirically. In addition, the use of "knowledge" has not consistently resulted in performance gains. After identifying possible reasons for previous negative results, we present a novel framework for "conceptual retrieval" that articulates the types of knowledge that are important for information seeking. We instantiate this general framework in the domain of clinical medicine based on the principles of evidence-based medicine (EBM). Experiments show that an EBM-based scoring algorithm dramatically outperforms a state-of-the-art baseline that employs only term statistics. Ablation studies further yield a better understanding of the performance contributions of different components. Finally, we discuss how other domains can benefit from knowledge-based approaches.
12964519
Development and evaluation of emerging design patterns for ubiquitous computing
Design patterns are a format for capturing and sharing design knowledge. In this paper, we look at a new domain for design patterns, namely ubiquitous computing. The overall goal of this work is to aid practice by speeding up the diffusion of new interaction techniques and evaluation results from researchers, presenting the information in a form more usable to practicing designers. Towards this end, we have developed an initial and emerging pattern language for ubiquitous computing, consisting of 45 pre-patterns describing application genres, physical-virtual spaces, interaction and systems techniques for managing privacy, and techniques for fluid interactions. We evaluated the effectiveness of our pre-patterns with 16 pairs of designers in helping them design location-enhanced applications. We observed that our pre-patterns helped new and experienced designers unfamiliar with ubiquitous computing in generating and communicating ideas, and in avoiding design problems early in the design process.
546802
A Low-Cost Checkpointing Technique for Distributed Databases
For distributed databases, checkpointing is used to ensure an efficient way to perform global reconstruction. However, the need for global reconstruction is infrequent. Most current checkpointing approaches for distributed databases are too expensive during run time. Some of them allow the checkpointing process to run in parallel with normal transactions at the cost of more data and resource contention, which in turn causes longer response time for normal transactions. Thus, an efficient way to checkpoint distributed databases is needed to avoid degrading the system performance. This paper presents a low-cost solution, called Loosely Synchronized Local Fuzzy Checkpointing (LSLFC), to these problems. LSLFC supports global reconstruction, and our performance study shows that LSLFC has little overhead during run time.
42438893
Some Decomposition Invariants of Crowns