In electronics and telecommunications, jitter is the deviation from true periodicity of a periodic signal in relation to a reference clock signal. In clock recovery applications it is called timing jitter. Jitter is a significant, undesired, factor in the design of all communications links. Jitter can be quantified in the same terms as all time-varying signals, e.g. root mean square, or peak-to-peak displacement. Like other time-varying signals, jitter can be expressed in terms of spectral density. Jitter period is the interval between two times of maximum effect of a signal characteristic that varies with time. Jitter frequency, the more quoted figure, is its inverse. ITU-T G.810 classifies jitter frequencies below 10 Hz as wander and frequencies at or above 10 Hz as jitter. Jitter may be caused by electromagnetic crosstalk with carriers of other signals. Jitter can cause a display monitor to flicker, affect the performance of processors in personal computers, introduce clicks or other undesired effects in audio signals, cause loss of transmitted data between network devices.
The amount of tolerable jitter depends on the affected application. For clock jitter, there are three used metrics: Absolute jitter The absolute difference in the position of a clock's edge from where it would ideally be. Period jitter The difference between the ideal or average clock period. Period jitter tends to be important in synchronous circuitry such as digital state machines where the error-free operation of the circuitry is limited by the shortest possible clock period, the performance of the circuitry is set by the average clock period. Hence, synchronous circuitry benefits from minimizing period jitter, so that the shortest clock period approaches the average clock period. Cycle-to-cycle jitter The difference in duration of any two adjacent clock periods, it can be important for some types of clock generation circuitry used in microprocessors and RAM interfaces. In telecommunications, the unit used for the above types of jitter is the unit interval which quantifies the jitter in terms of a fraction of the transmission unit period.
This unit is useful because it scales with clock frequency and thus allows slow interconnects such as T1 to be compared to higher-speed internet backbone links such as OC-192. Absolute units such as picoseconds are more common in microprocessor applications. Units of degrees and radians are used. If jitter has a Gaussian distribution, it is quantified using the standard deviation of this distribution; this translates to an RMS measurement for a zero-mean distribution. Jitter distribution is non-Gaussian; this can occur. In these cases, peak-to-peak measurements may be more useful. Many efforts have been made to meaningfully quantify distributions that are neither Gaussian nor have a meaningful peak level. All most tend to be good enough for the purposes of engineering work. Note that the reference point for jitter is defined such that the mean jitter is 0. In computer networking, jitter can refer to packet delay variation, the variation in the delay of the packets. One of the main differences between random and deterministic jitter is that deterministic jitter is bounded and random jitter is unbounded.
Random Jitter called Gaussian jitter, is unpredictable electronic timing noise. Random jitter follows a normal distribution due to being caused by thermal noise in an electrical circuit or due to the central limit theorem; the central limit theorem states that composite effect of many uncorrelated noise sources, regardless of the distributions, approaches a normal distribution. Deterministic jitter is a type of clock or data signal jitter, predictable and reproducible; the peak-to-peak value of this jitter is bounded, the bounds can be observed and predicted. Deterministic jitter has a known non-normal distribution. Deterministic jitter can either uncorrelated to the data stream. Examples of data-dependent jitter are intersymbol interference. Total jitter is the combination of random jitter and deterministic jitter and is computed in the context to a required bit error rate for the system: T = Dpeak-to-peak + 2nRrms,in which the value of n is based on the BER required of the link. A common BER used in communication standards such as Ethernet is 10−12.
In analog-to-digital and digital-to-analog conversion of signals, the sampling is assumed to be periodic with a fixed period—the time between every two samples is the same. If there is jitter present on the clock signal to the analog-to-digital converter or a digital-to-analog converter, the time between samples varies and instantaneous signal error arises; the error is proportional to the slew rate of the desired signal and the absolute value of the clock error. The effect of jitter on the signal depends on the nature of the jitter. Random jitter tends to add broadband noise while periodic jitter tends to add errant spectral components, "birdys". In some conditions, less than a nanosecond of jitter can reduce the effective bit resolution of a converter with a Nyquist frequency of 22 kHz to 14 bits. Sampling jitter is an important consideration in high-frequency signal conversion, or where the clock signal is prone to interference. In the context of computer networks, packet jitter or packet delay variatio
Robert Stewart was a Canadian of Scottish origin who became first Speaker of the Legislative Assembly of Prince Edward Island, serving in this position from 1773 until 1779. Robert Stewart was born in 1731, his grandfather was the Reverend Dugald Stewart of Rothesay. One of his cousins was Dugald Stewart, the Mathematician and Philosopher, a Professor at the University of Edinburgh, he married daughter of the Reverend Charles Stewart. They had eight children. Annabella was sister of Lieutenant Colonel Robert Stewart and of Peter Stewart, who became first Chief Justice of St. John island, as Prince Edward Island was called. For some time Stewart was a fish merchant in Campbeltown, but was not successful. In 1770 Robert and Annabella Stewart emigrated to Prince Edward Island, they sailed from Campbeltown on the brigantine Annabella, captained by Dugald Stewart and carrying one hundred passengers from Argyll. Dugald Stewart was Annabella's brother. Robert Stewart organized the first settlement in Malpeque Bay, on the north shore of the center of the island.
His brother-in-law Lieutenant Colonel Robert Stewart took over the leadership of the settlement. Robert Stewart of Cambelford was recognized as a leader of the island's community, became the first speaker of the province's parliament when it was founded in 1773; the first House of Assembly held only one session. Citations Sources
Rio Díaz-Cojuangco, was a Filipino beauty queen, television presenter and politician. The sister of former Miss Universe 1969 Gloria Díaz, she was diagnosed with stage four colon cancer and died in the United States in 2004, she was an aunt of Georgina Wilson, through another sister Aurora, Wilson's mother. Born in Manila, Díaz was the youngest of twelve children born to Teresa Aspillera. A ramp and commercial model, she was crowned Mutya ng Pilipinas in 1977 and won Fourth Runner-up in the Miss Asia Pageant that same year. Díaz began a relationship with musician Hajji Alejandro, together they emigrated to Los Angeles, where they operated a small restaurant along Melrose Avenue. After separating from Alejandro, Díaz returned to the Philippines and resumed her career in entertainment, she co-hosted Eat Bulaga in 1991 and stayed for a couple of years before meeting Charlie Cojuangco on a blind date in 1993 and marrying him the following year. For the greater part of the 1990s, Díaz starred in several films.
She was elected vice-mayor of Pontevedra, Negros Occidental in the 1998 elections, while her husband won a seat in Congress. Díaz became president of the vice-mayors' league of Negros Occidental. During a routine checkup in December 1998, her American doctors informed her of a small growth in her left abdomen. After a six-hour surgery, they found a malignant tumour in its fourth stage, Díaz was given three months to live, she underwent another operation, received chemotherapy for three months. In 1999, Stanford oncologist Dr George Fisher, declared she had been cured; when the cancer cells returned in May 2000, Rio travelled back to Stanford for an eight-hour surgical procedure and another round of chemotherapy sessions. Díaz stopped the sessions in 2002, citing her body's inability to cope further, but her physicians that year said she had no recourse but to continue treatment. Six years after the original diagnosis, Díaz died on 4 October 2004 at Seton Medical Center in Daly City, California, at the age of 45.
Tunay na Magkaibigan, Walang Iwanan... Peksman Sam & Miguel as Mila Sísingilín Ko ng Dugo Eat Bulaga! Sarap TV Maalaala Mo Kaya, "Pictures": The Rio Díaz-Cojuangco Story - as herself Rio is Safely Home
The Lysippides Painter worked in Athens in the second half of the 6th century BC. He was a black-figure painter of a classic style, he most trained with Ezekias in his workshop until moving to the Andokides workshop where he painted large, expensive vases and did some work on bilingual vases with Andokides P being the red-figure painter. He was named, after much debate ensuring he was not the Andokides Painter using red-figure, after a Kalos found on one of his vases. Of the 204 Vases attributed to Lysippides P in the Beazley archives, 112 are large amphorae; these contain all variations of Amphorae, Amphora A, Amphora B, Amphora Neck, 4 Panathenaic Amphorae. There are 32 cups consisting of Cup A and Little Master Band Variations; the basins of many of these large cups are decorated with the face of a gorgonian. These Gorgonians are typical of the Nikostenes workshop to which, it has been argued, Lysippides was lent; some of the other shapes that Lysippides works with are Krater, Oinchoes and Pyxis.
These shapes have small numbers, but many of them carry the same subjects as those of other Lysippides vases. Most of these vases appear to have been traded to Italy the area around Rome, Etruria. Of the 85 vases that have listed provenances, 74 were shipped to Italy and over of 50 of these to the Etruria region; the other provenances include Sicily and Turkey, but they appear in nominal numbers. Herakles is the favorite subject of the Lysippides Painter. IT is a favorite of most Group E vase-painters. Of the 204 vases in the Beazley Archive there are over 60 of Herakles in various forms of heroism, fighting the lion, mounting chariots with Athena, fighting Amazons, fighting giants, he is always shown in his lion cape, with hood resting on the back of his black hair, defined with white paint. The arms of the lion are tied around his chest. Warriors and fights are important in Lysippides' vases; some show warriors fighting over a fallen soldier, others show battles. All soldiers have Boeotiaon shields and spears, many with Corinthian helmets.
They are typical of ancient Greek vases, show glory, arête and honor, all values held high by the Greeks. Other subjects include Amazonomachys and scene with Dionysos surrounded by the double-leafed vine. While the shape of the vase is considered to be chosen by the workshop, the subject could well have been the decision of the artist himself. While these subjects chosen are typical of many Greek vases the prevalence of Herakles in Lysippides vases is significant of both his style and interests, he was commissioned for his fine work in the painting of Herakles. The images are tenderly rendered with exquisite detail, it is probable that Lysippides painter worked in the Andokides workshop. The Andokides workshop was known for it more high quality pieces and Lysippides was a skilled black-figure painter of the time. One of the styles that came from the Andokides workshop was the bilingual vase. Beth Cohen, in'Colors of Clay' suggests that Andokides was one of the first red-figure painters and suggests that he may have been an inventor of the style.
While creating bilingual vases with different black-figure painters, such as Lysippides, Andokides would paint one side of the vase in red-figure and another painter would paint the other in black-figure. In the case of cups the red-figure painter would paint the inside and the black-figure painter would paint the outside. There are six bilingual vases in the Beazley Archives attributed to both Andokides P and Lysippides P. Many archeologists have debated the validity of the bilingual model, suggesting that one artist painted the vessels. In two styles; however Cohen, with the assistance of other such as Mary B Moore, cited general differences that distinguish the two styles, such as the Andokides painter’s preference for larger, more lifelike, images with less detail, the influence of Exekias on the more conservative style of the Lysippides painter, in support of the bilingual model. While Cohen and Moore seem to consider the newly discovered technique to be more advanced and lifelike that the older black-figure style, there is something to be said for the detail and care, clear from the stylized black-figure that adds a dimension that the red-figure is lacking.
Of course, because red-figure painting was new its distinct style may not have evolved to the stage that black-figure had the chance to in their longer history. Corpus vasorum antiquorum
Tert-Butyllithium is a chemical compound with the formula 3CLi. As an organolithium compound, it has applications in organic synthesis since it is a strong base, capable of deprotonating many carbon acids, including benzene. Tert-Butyllithium is available commercially as hydrocarbon solutions, its synthesis was first reported by R. B. Woodward in 1941. Like other organolithium compounds, tert-butyllithium is a cluster. Whereas n-butyllithium exists both as a hexamer and a tetramer, tert-Butyllithium exists as tetramer with a cubane structure. Bonding in organolithium clusters involves sigma delocalization and significant Li—Li bonding; the lithium–carbon bond in tert-butyllithium is polarized, having about 40 percent ionic character. The molecule reacts like a carbanion. Similar to n-butyllithium, tert-butyllithium can be used for the exchange of lithium with halogens and for the deprotonation of amines and activated C—H compounds; this compound and other alkyllithium compounds are known to react with ether solvents.
In this example, the reaction of tert-butyllithium with is shown: To minimize degradation by these solvents, reactions involving tert-butyllithium are conducted at low temperatures in special solvents, such as the Trapp solvent mixture. Tert-Butyllithium is a pyrophoric substance, meaning that it catches fire on exposure to air; the solvents used in common commercial preparations are themselves flammable. While it is possible to work with this compound using cannula transfer, traces of tert-butyllithium at the tip of the needle or cannula may catch fire and clog the cannula with lithium salts. While some researchers take this "pilot light" effect as a sign that the product is "fresh" and has not degraded due to time or improper storage/handling, some workers prefer to enclose the needle tip or cannula in a short glass tube, flushed with an inert gas and sealed at each end with septa. Serious laboratory accidents involving tert-butyllithium have occurred. For example, in 2008 a staff research assistant, Sheharbano Sangji, in the lab of Patrick Harran at the University of California, Los Angeles, died after being burned by a fire ignited by tert-butyllithium.
Large-scale reactions may lead to runaway reactions and explosions when tert-butyllithium is mixed with ethers such as diethyl ether, tetrahydrofuran. The use of hydrocarbon solvents may be preferred. Air-free techniques are important so as to prevent this compound from reacting violently with oxygen and moisture in the air: t-BuLi + O2 → t-BuOOLi t-BuLi + H2O → t-BuH + LiOH
LiQin Tan is a Chinese-born American digital artist and educator who has taught in China, Canada and the U. S. A. Tan is a full co-director of art program at Rutgers University-Camden, he has served as a board member of the Digital Art Committee, SIGGRAPH and as a juror for the digital art gallery at SIGGRAPH. He was one of the activists during the ’85 art trend of China. In addition, he has worked as an art director, graphic designer and executive art editor in local and board industries. Since transferring to the field of digital art, he has pioneered the "Digital-Primitive” and “Digital Nature” concepts, which has won great acclaim and a number of awards from both American and international art scenes, his artwork has been internationally in both solo and group shows. Such as SIGGRAPH, Electronics Alive IV, iDMAa04-08, the National Art Museum of China, Moscow Int’l Festival of Animation & Media Art, the Beijing World Art Museum, the Vancouver Art Gallery, the Shanghai DuoLun Museum of Modern Art, the National Centre for Computer Animation in UK, the Centre D’Art Contemporaine in Montreal, the Singapore Art Museum, the LaSalle Univ.
Art Museum, the Noyes Museum of Art, the Jiangsu Art Gallery, Beijing Song Zhuang Art Museum and the Guang Dong Art Museum, amongst others. Tan's art research since 2000 has focused on the merging of conceptual animation, animation installation, interactive animation, digital prints on rigid materials, his resulting work was awarded first place from the 5th Digital Art and Computer Animation Competition by the Beecher Center for Art and Technology, the "Best of Show" at iDEAa. He has been awarded first place, as well as the excellence prize from the China Academy Awards; the Award of Excellence by the International Digital IV, the Award of Excellence at the Global Media Competition from gallery international etc. His publications include a number of articles regarding technological singularity art, contemporary art, art criticism, art education, animation. In addition to these articles are his books and catalogues, such as Singularity Art: How Technological Singularity Will Impact Art, Singularity: Subversive BioArt,Digital Natural Art, Digital Artwork Collection II, Character Animation & Rigging, Tan On Art/Art On Tan.
His in-progress books are: Singularity: Invisible Art and Singularity: Strong A. I. Art. 1957: Born in Hengshan County, China into an educators’ family. Father: high school principal, Mother: elementary school teacher. 1966-1968: Joined the “Little Red Guards” during the Cultural Revolution and learned Chinese through writing "3-Character Classic” posters. School closed, with teachers’ families tucked into a sealed library to read - his favorites were comics and popular science books. 1969-1970: Moved from the city to father's old farm-house in the countryside. 1971-1972: Enrolled at the Hengdong 5th High School and won several math competition awards with the guidance of Math teacher Xie. 1973-1975: Was An instructor at Dapu Town Elemental School and participated in country art activities. 1975-1976: Well-known artists Zhong Zhengya and Mr. Liao Xianwu became his masters. 1976-1977: Hired as the design-artist at the Headquarter of the Hengdong Yangtong Hydra Station. The boiling popular site was the best materials for his art and his first large site sketch was published by Hengyang Daily.
1977-1978: Hired as design-artist at Hengdong Radio Equipment Factory. 1978-1981: Admitted to fine arts department of the Hengyang Normal University and won provincial and city art awards. By "Talent Study" impacts, drilled into a cold research on "art education and psychology" with encouragement from famous aesthetician Hong Yiran, read books on aesthetics and psychology, the first article was published in the Hengyang Teachers' College Magazine. 1981-1982: Stayed on school as a faculty to taught Chinese figure painting, human anatomy. Education Research published two art education articles, participated in Hunan Minorities Art Exhibition and Hunan ‘81 Art Exhibition with 2nd place award. 1982-1984: Studied at the Art History Department of the Central Academy of Fine Arts and Learned Chinese and Western art history thoroughly. The concepts of contemporary Western art changed his way of thinking and won 2nd place from Student Art Competition at Central Academy of Fine Arts. 1984: Married Ms. Dong in the summer, in Changsha City.
Returned to Hengyang Normal University as faculty and taught Chinese art history and Chinese figure painting. Works were entered into the 6th National Art Hunan award-winner exhibition. Participated in a number of theoretical seminars for 6th National Art Exhibition in Nanjing and raised a few strong concepts against the prevailing conservative viewpoint. Attended National Aesthetic Seminar at Zhangjiajie, Hunan. 1985-1987: As an art editor at Hunan Fine Arts Publishing House, founded an avant-garde art magazine Painter with others. Participated in the ‘85 Art Trend, such as seminars and group activities, first spotted and recommended Gu Wenda’s art with large layout publications.