We study the problem of finding all k-periods of a length-n string S, presented as a data stream. S is said to have k-period p if its prefix of length n− p differs from its suffix of length n− p in at most k locations. We give a one-pass streaming algorithm that computes the k-periods of a string S using poly(k, logn) bits of space, for k-periods of length at most n 2 . We also present a two-pa...

We study the stream merging problem for media-on-demand servers. Clients requesting media from the server arrive by a Poisson process, and delivery to the clients starts immediately. Clients are prepared to receive up to two streams at any time, one or both being fed into a buffer cache. We present an on-line algorithm, the dyadic stream merging algorithm, whose recursive structure allows us to...

To learn a language, speakers must learn its words and rules from fluent speech; in particular, they must learn dependencies among linguistic classes. We show that when familiarized with a short artificial, subliminally bracketed stream, participants can learn relations about the structure of its words, which specify the classes of syllables occurring in first and last word positions. By studyi...

Usually, a streaming algorithm is used in scenarios in which there are a lot of data (items) arriving and there is a space or time limitation for storage of data and processing later. More precisely, streaming algorithms are on-line algorithms which process the data streams. Each data stream is a long sequence of items arriving rapidly, denoted by I1, I2, ..., It, ..., Im where It is the t th i...

Geomorphometry of headwater catchments has been poorly reported in the Central-Eastern Pyrenees. This study presents a series of parameters obtained for Central-Eastern Pyrenean headwater catchments. The database consists of 3005 1and 655 2-order catchments. These catchments have been digitalised, identified, and attributed a value for each parameter. The parameters investigated are divided int...

Time-Memory-Data tradeoff attacks (TMD-attacks) like those of Babbage [1], Biryukov and Shamir [2] and Dunkelman, Keller [5] reduce the security level of keystream generator based-stream ciphers to L/2, where L denotes the inner state length. This is one of the reasons why stream ciphers like Trivium [3] and Grain [8] use a session key length n of at most L/2. In this paper, we deal with the qu...

Diatom assemblages from four different substrates from a stream on Byers Peninsula were analysed during the summer. The substrate type was the main factor explaining the variability in the diatom assemblages. Sandy biofilms showed a higher diversity and a greater number of endemic species. Two main hydrological regimes were observed: 1) a hydrologically unstable period with high variability in ...

Question: How do post-glacial colonization history and current watershed geomorphology affect population genetic structure in lacustrine fish populations? Study system: Eleven populations of lacustrine threespine sticklebacks (Gasterosteus aculeatus) from a single watershed, and two adjacent marine populations of G. aculeatus as outgroups. Methods: Individuals were genotyped using six microsate...

The extent of contamination of fish in the Mid-Atlantic Region was evaluated as part of the U.S. Environmental Protection Agency's Monitoring and Assessment Program's regional assessment in 1993 through 1994. Fish assemblages from wadeable streams were dominated by small, short-lived fishes (e.g., minnows, darters, and sculpins) that were more widely distributed and abundant than large fishes t...

The urban stream syndrome may not be limited to streams in urbanized watersheds. We measured the spatial pattern of impervious cover in ∼82,800 small watersheds across the conterminous United States by comparing watershed-based and stream-based measures of imperviousness. The watershed-based measure was the commonly used watershed percentage impervious cover. The stream-based measure was the pe...