Civil Rights
Movements, leaders, victories and the continuing fight for equality.
Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
Innovation, patents, science, technology and world-changing contributions.
Pioneers, champions, Negro Leagues, records, activism and excellence.
Meet the people whose lives, choices and achievements shaped the journey.
Black towns, communities, institutions and places where history happened.
Moments that changed communities, movements, institutions and the nation.
In 1968 Shirley Chisholm became the first Black woman elected to the United States Congress. In 1972 she launched a campaign for the Democratic presidential nomination, breaking another political barrier.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
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FS-1016 (also called FED-STD-1016) is a deprecated secure telephony speech encoding standard for Code-excited linear prediction (CELP) developed by the United States Department of Defense and finalized February 14, 1991.[1]
Unlike the vocoder used in FS-1015, CELP provides more natural speech. However, due to quite low bit rate and early development (1991), the speech quality is very noisy and below that of commercial cellular speech codec, such as AMR. FS-1016 is no longer used since its follow-up MELP provides better performance in all applications.
The bit rate of the codec is 4.8 kbit/s. The complexity of the codec is 19 MIPS. The RAM requirement is 1.5 kilobytes. Frame size of the codec is 30 ms. Look-ahead of 7.5 ms is also required.
The variation of CELP used in the FS-1016 is so-called ternary codebook, meaning that all excitation amplitudes are either +1, −1 or 0. The sub frame gain is calculated and sent to the receiver.
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FS-1016 (also called FED-STD-1016) is a deprecated secure telephony speech encoding standard for Code-excited linear prediction (CELP) developed by the United States Department of Defense and finalized February 14, 1991. Unlike the vocoder used in FS-1015, CELP provides more natural speech. However, due to quite low bit rate and early development (1991), the speech quality is very noisy and below that of commercial cellular speech codec, such as AMR. FS-1016 is no longer used since its follow-up MELP provides better performance in all applications.
Code-excited linear prediction (CELP) is a linear predictive speech coding algorithm originally proposed by Manfred R. Schroeder and Bishnu S. Atal in 1985. At the time, it provided significantly better quality than existing low bit-rate algorithms, such as residual-excited linear prediction (RELP) and linear predictive coding (LPC) vocoders (e.g., FS-1015). Along with its variants, such as algebraic CELP, relaxed CELP, low-delay CELP and vector sum excited linear prediction, it is currently the most widely used speech coding algorithm. It is also used in MPEG-4 Audio speech coding. CELP is commonly used as a generic term for a class of algorithms and not for a particular codec.
Code page 1015 (CCSID 1015), also known as CP1015, is IBM's code page for the Portuguese version of ISO 646 for Portugal.
This page contains a list of petawatt-level lasers in operation, under construction, or proposed. The list is compiled from existing academic reviews. A petawatt laser is typically defined as a laser system whose pulse energy divided by its pulse duration reaches an order of magnitude of 1015 W, or 1 petawatt. These high-power laser pulses are capable of driving a strong electromagnetic field, giving rise to a number of novel applications. For instance, focusing large numbers of petawatt level lasers on a target containing deuterium and tritium creates enough energy density to drive inertial confinement fusion. Another potential application is using strong electric fields from petawatt laser pulses to drive steep density gradient structures in a plasma, which then creates field gradients capable of accelerating particles in a much shorter distance than linac; such concept is known as laser wakefield acceleration. In addition, as the laser pulse itself reaches extremely high field intensity, interaction of the high-energy particle beam with a petawatt laser pulse can achieve interactions with intensity beyond the Schwinger limit, enabling possible observation of effects such as vacuum polarization and Breit-Wheeler process. Generation of a petawatt laser pulse requires the pulse duration to be extremely short: to reach 1 petawatt of power, a 1 joule laser pulse will require a duration of
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Madam C.J. Walker