The shifting sands algorithm
نویسندگان
چکیده
We resolve the problem of small-space approximate selection in random-order streams. Specifically, we present an algorithm that reads the n elements of a set in random order and returns an element whose rank differs from the true median by at most n while storing a constant number of elements and counters at any one time. This is optimal: it was previously shown that achieving better accuracy required poly(n) memory. However, it was conjectured that the lower bound was not tight and that a previous algorithm achieving an n approximation was optimal. We therefore consider the new result a surprising resolution to a natural and basic question.
منابع مشابه
Iranian Wedding Invitations in the Shifting Sands of Time
As a distinct socially constructed genre, wedding invitations (WIs) offer a fruitful site for investigating how two areas of genre knowledge (i.e., form and content) change over time under the influence of sociocultural forces. Through the examination of 100 Iranian WIs dating from 1970s to the present time, the study investigated the trajectories of change through time within the social semiot...
متن کاملEnglish Language Teaching in Iran: A Case of Shifting Sands, Ambiguity, and Incoherent Policy and Practice
English language teaching (ELT) in Iran has experienced a turbulent history reflecting an often dynamic context and changing attitudes toward English, yet framed within a discourse of tolerance rather than one of embrace, as this study is going to show. The discourse was much brighter before the Islamic Revolution and this study reveals that there were much fewer adverse policies toward the spr...
متن کاملShifting Sands and Changing Minds: The Role of the European Parliament in the Area of Freedom, Security and Justice
متن کامل
Shifting Sands: An Interest-Relative Theory of Vagueness
Please quote or cite page numbers from published version only.
متن کاملOptimal Operation of Microgrids Under Demand Side Management
One of the major problem in the optimal operation of the power system is optimal operation of microgrid with regard to the Demand-side-management. From one side, demand-side-management programs reduce the operating costs of the power system and on the other hand, the implementation of these programs requires a financial incentive policies. In this paper, optimal operation of microgrid with dem...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2012