Have a deep view into what people are curious about.

🔗 Statistics

Nelson rules are a method in process control of determining if some measured variable is out of control (unpredictable versus consistent). Rules, for detecting "out-of-control" or non-random conditions were first postulated by Walter A. Shewhart in the 1920s. The Nelson rules were first published in the October 1984 issue of the Journal of Quality Technology in an article by Lloyd S Nelson.

The rules are applied to a control chart on which the magnitude of some variable is plotted against time. The rules are based on the mean value and the standard deviation of the samples.

The above eight rules apply to a chart of a variable value.

A second chart, the moving range chart, can also be used but only with rules 1, 2, 3 and 4. Such a chart plots a graph of the maximum value - minimum value of N adjacent points against the time sample of the range.

An example moving range: if N = 3 and values are 1, 3, 5, 3, 3, 2, 4, 5 then the sets of adjacent points are (1,3,5) (3,5,3) (5,3,3) (3,3,2) (3,2,4) (2,4,5) resulting in moving range values of (5-1) (5-3) (5-3) (3-2) (4-2) (5-2) = 4, 2, 2, 1, 2, 3.

Applying these rules indicates when a potential "out of control" situation has arisen. However, there will always be some false alerts and the more rules applied the more will occur. For some processes, it may be beneficial to omit one or more rules. Equally there may be some missing alerts where some specific "out of control" situation is not detected. Empirically, the detection accuracy is good.

🔗 Computing

Personal knowledge management (PKM) is a process of collecting information that a person uses to gather, classify, store, search, retrieve and share knowledge in their daily activities (Grundspenkis 2007) and the way in which these processes support work activities (Wright 2005). It is a response to the idea that knowledge workers need to be responsible for their own growth and learning (Smedley 2009). It is a bottom-up approach to knowledge management (KM) (Pollard 2008).

🔗 Geology 🔗 Michigan 🔗 Gemology and Jewelry/Gemstones 🔗 Gemology and Jewelry

A Petoskey stone is a rock and a fossil, often pebble-shaped, that is composed of a fossilized rugose coral, Hexagonaria percarinata. Such stones were formed as a result of glaciation, in which sheets of ice plucked stones from the bedrock, grinding off their rough edges and depositing them in the northwestern (and some in the northeastern) portion of Michigan's lower peninsula. In those same areas of Michigan, complete fossilized coral colony heads can be found in the source rocks for the Petoskey stones.

Petoskey stones are found in the Gravel Point Formation of the Traverse Group. They are fragments of a coral reef that was originally deposited during the Devonian period. When dry, the stone resembles ordinary limestone but when wet or polished using lapidary techniques, the distinctive mottled pattern of the six-sided coral fossils emerges. It is sometimes made into decorative objects. Other forms of fossilized coral are also found in the same location.

In 1965, it was named the state stone of Michigan.

🔗 Books 🔗 Mongols

The Tartar Relation (Latin: Hystoria Tartarorum, "History of the Tartars") is an ethnographic report on the Mongol Empire composed by a certain C. de Bridia in Latin in 1247. It is one of the most detailed accounts of the history and customs of the Mongols to appear in Europe around that time.

🔗 Computing 🔗 Cognitive science 🔗 Computing/Computer science 🔗 Human–Computer Interaction

Fitts's law (often cited as Fitts' law) is a predictive model of human movement primarily used in human–computer interaction and ergonomics. This scientific law predicts that the time required to rapidly move to a target area is a function of the ratio between the distance to the target and the width of the target. Fitts's law is used to model the act of pointing, either by physically touching an object with a hand or finger, or virtually, by pointing to an object on a computer monitor using a pointing device.

Fitts's law has been shown to apply under a variety of conditions; with many different limbs (hands, feet, the lower lip, head-mounted sights), manipulanda (input devices), physical environments (including underwater), and user populations (young, old, special educational needs, and drugged participants).

🔗 Java 🔗 Project-independent assessment

A Java processor is the implementation of the Java virtual machine (JVM) in hardware. In other words, the Java bytecode that makes up the instruction set of the abstract machine becomes the instruction set of a concrete machine. These were the most popular form of a high-level language computer architecture, and were "an attractive choice for building embedded and real-time systems that are programmed in Java". However, as of 2017, embedded Java is no longer common and no realtime Java chip vendors exist.

🔗 California 🔗 Companies 🔗 California/San Francisco Bay Area 🔗 Internet 🔗 Food and drink

Webvan was a dot-com company and grocery business that filed for bankruptcy in 2001 after 3 years of operation. It was headquartered in Foster City, California, United States. It delivered products to customers' homes within a 30-minute window of their choosing. At its peak, it offered service in ten US markets: the San Francisco Bay Area; Dallas; Sacramento; San Diego; Los Angeles; Orange County, California; Chicago; Seattle; Portland, Oregon; and Atlanta, Georgia. The company had hoped to expand to 26 cities by 2001.

🔗 India 🔗 India/Indian literature workgroup

The Shishupala Vadha (Sanskrit: शिशुपालवध, IAST: Śiśupāla-vadha, lit. "the slaying of Shishupala") is a work of classical Sanskrit poetry (kāvya) composed by Māgha in the 7th or 8th century. It is an epic poem in 20 sargas (cantos) of about 1800 highly ornate stanzas, and is considered one of the six Sanskrit mahakavyas, or "great epics". It is also known as the Māgha-kāvya after its author. Like other kavyas, it is admired more for its exquisite descriptions and lyrical quality than for any dramatic development of plot. Its 19th canto is noted for verbal gymnastics and wordplay; see the section on linguistic ingenuity below.

🔗 History 🔗 Europe 🔗 Ukraine 🔗 Archaeology 🔗 Romania 🔗 Moldova

In the archaeology of Neolithic Europe, the burned house horizon is the geographical extent of the phenomenon of presumably intentionally burned settlements.

This was a widespread and long-lasting tradition in what is now Southeastern and Eastern Europe, lasting from as early as 6500 BCE (the beginning of the Neolithic) to as late as 2000 BCE (the end of the Chalcolithic and the beginning of the Bronze Age). A notable representative of this tradition is the Cucuteni-Trypillian culture, which was centered on the burned-house horizon both geographically and temporally.

There is still a discussion in the study of Neolithic and Eneolithic Europe whether the majority of burned houses were intentionally set alight or not.

Although there is still debate about the why house burning was practiced, the evidence seems to indicate that it was highly unlikely to have been accidental. There is also debate about why this would have been done deliberately and regularly, since these burnings could destroy the entire settlement. However, in recent years, the consensus has begun to gel around the "domicide" theory supported by Tringham, Stevanovic and others.

Cucuteni-Trypillian settlements were completely burned every 75–80 years, leaving behind successive layers consisting mostly of large amounts of rubble from the collapsed wattle-and-daub walls. This rubble was mostly ceramic material that had been created as the raw clay used in the daub of the walls became vitrified from the intense heat that would have turned it a bright orange color during the conflagration that destroyed the buildings, much the same way that raw clay objects are turned into ceramic products during the firing process in a kiln. Moreover, the sheer amount of fired-clay rubble found within every house of a settlement indicates that a fire of enormous intensity would have raged through the entire community to have created the volume of material found.

🔗 Medicine 🔗 China 🔗 Plants 🔗 Pharmacology 🔗 Psychoactive and Recreational Drugs

For over two millennia, texts in Chinese herbology and traditional Chinese medicine have recorded medicinal plants that are also hallucinogens and psychedelics. Some are familiar psychoactive plants in Western herbal medicine (e.g., Chinese: 莨菪; pinyin: làngdàng, i.e. Hyoscyamus niger), but several Chinese plants have not been noted as hallucinogens in modern works (e.g.,Chinese: 雲實; pinyin: yúnshí; lit. 'cloud seed', i.e. Caesalpinia decapetala). Chinese herbals are an important resource for the history of botany, for instance, Zhang Hua's c. 290 Bowuzhi is the earliest record of the psilocybin mushroom xiàojùn 笑菌 (lit. "laughing mushroom", i.e. Gymnopilus junonius).