A fountain code produces for given set of k input symbols (x1, . . . , xk) a potentially limitless stream of output symbols z1, z2, . . .. The input and output symbols can be binary vectors of arbitrary length. Each output symbol is the sum of a randomly and independently chosen subset of the input symbols. Information describing the relations between input and output symbols is obtained at the...

We monitored geyser activity in the Lower Geyser Basin (LGB) of Yellowstone National Park with dual four-element microphone arrays separated by ~600 m. The arrays were independently used to identify incident coherent plane wave energy, then conjoint cross beam back-azimuths from the two arrays were used to precisely locate signal sources. During a week in August 2011 we located repeating infras...

This report presents a real-time simulation of a music fountain which is simulated in three dimensions by a particle animation system. In this system, gravity and wind are factors that affect the locus movement of particles. Using kinematic equations, the dynamic behaviors of particles is modeled. A specific contribution of the work presented here is that parameters for the motion equation are ...

یکی از پارامترهای مهم محیط­های پخش نوترون، طول نوترون حرارتی است. روش مرسوم محاسباتی استفاده کد MCNP برمبنای توزیع شار در محیط و برازش تابع ریاضی مربوطه بر آن این پژوهش، روشی نوین که مبنای کارت PTRAC است، ارایه شده پارامتر برای آب­سبک اساس روش­های فوق محاسبه با مقادیر گزارش مراجع مقایسه گردیده تطابق خوبی نیز مشاهده حسن فوق، عدم نیاز به علاوه فرض می­شود تا محل چشمه، فاصله­ی کافی وجود دارد. مسأله...

We report on a preliminary design of a new Kalman-filter Hydrogen-maser time scale at NIST. The time scale is composed of a few Hydrogen masers and a Cs clock. The Cs clock is used as a reference clock, to ease operations with existing data. All the data used in this paper are real measurement data, except mentioned specifically. Unlike most other time scales, this time scale uses three basic t...

An ensemble of rubidium atomic fountain clocks has been put into operation at the US Naval Observatory (USNO). These fountains are used as continuous clocks in the manner of commercial caesium beams and hydrogen masers for the purpose of improved timing applications. Four fountains have been in operation for more than two years and are included in the ensemble used to generate the USNO master c...