Twentieth-century iconography

In the early-twentieth century Germany, Aby Warburg (1866–1929) and his followers Fritz Saxl (1890–1948) and Erwin Panofsky (1862–1968) elaborated the practice of identification and classification of motifs in images to using iconography as a means to understanding meaning. Panofsky codified an influential approach to iconography in his 1939 Studies in Iconology, where he defined it as "the branch of the history of art which concerns itself with the subject matter or meaning of works of art, as opposed to form,"[3] although the distinction he and other scholars drew between particular definitions of "iconography" (put simply, the identification of visual content) and "iconology" (the analysis of the meaning of that content), has not been generally accepted, though it is still used by some writers.

In the United States, where Panofsky immigrated in 1931, students such as Frederick Hartt, and Meyer Schapiro continued under his influence in the discipline. In an influential article of 1942, Introduction to an "Iconography of Mediaeval Architecture", Richard Krautheimer, a specialist on early medieval churches and another German emigré, extended iconographical analysis to architectural forms.

The period from 1940 can be seen as one where iconography was especially prominent in art history. Whereas most icongraphical scholarship remains highly dense and specialized, some analyses began to attract a much wider audience, for example Panofsky's theory (now generally out of favour with specialists) that the writing on the rear wall in the Arnolfini Portrait by Jan van Eyck turned the painting into the record of a marriage contract. Holbein's The Ambassadors has been the subject of books for a general market with new theories as to its iconography, and the best-sellers of Dan Brown include theories, disowned by most art historians, on the iconography of works by Leonardo da Vinci.

Technological advances allowed the building-up of huge collections of photographs, with an iconographic arrangement or index, which include those of the Warburg Institute and the Index of Christian Art at Princeton (which has made a specialism of iconography since its early days in America). These are now being digitised and made available online, usually on a restricted basis.

With the arrival of computing, the Iconclass system, a highly complex way of classifying the content of images, with 28,000 classification types, and 14,000 keywords, was developed in the Netherlands as a standard classification for recording collections, with the idea of assembling huge databases that will allow the retrieval of images featuring particular details, subjects or other common factors. For example, the Iconclass code "71H7131" is for the subject of "Bathsheba (alone) with David's letter", whereas "71" is the whole "Old Testament" and "71H" the "story of David". A number of collections of different types have been classified using Iconclass, notably many types of old master print, the collections of the Gemäldegalerie, Berlin and the German Marburger Index. These are available, usually on-line or on DVD. The system can also be used outside pure art history, for example on sites like Flickr.

Paleolithic

Paleolithic means "Old Stone Age." This was the earliest period of the Stone Age. The Lower Paleolithic predates Homo sapiens, beginning with Homo habilis and the earliest use of stone tools some 2.5 million years ago. Homo sapiens originated some 200,000 years ago, ushering in the Middle Paleolithic.

Sometime during the Middle Paleolithic, humans also developed language, music, early art, as well as systematic burial of the dead.

Humans spread from East Africa to the Near East some 80 millennia ago, and further to southern Asia and Australasia some 60 millennia ago, northwestwards into Europe and eastwards into Central Asia some 40 millennia ago, and further east to the Americas from ca. 15 millennia ago. The Upper Paleolithic is taken to begin some 40 millennia ago, with the appearance of "high" culture. Expansion to North America and Oceania took place at the climax of the most recent Ice Age, when today's temperate regions were extremely inhospitable. By the end of the Ice Age some 12,000 BP, humans had colonised nearly all the ice-free parts of the globe.

Throughout the Paleolithic, humans generally lived as nomadic hunter-gatherers. Hunter-gatherer societies have tended to be very small and egalitarian, though hunter-gatherer societies with abundant resources or advanced food-storage techniques have sometimes developed a sedentary lifestyle, complex social structures such as chiefdoms, and social stratification; and long-distance contacts may be possible, as in the case of Indigenous Australian "highways."

Wi-Fi Reach

Due to reach requirements for wireless LAN applications, power consumption is fairly high compared to some other low-bandwidth standards. Especially Zigbee and Bluetooth supporting wireless PAN applications refer to much lesser propagation range of <10m (ref. e.g. IEEE Std. 802.15.4 section 1.2 scope). Range is always making battery life a concern.

Wi-Fi networks have limited range. A typical Wi-Fi home router using 802.11b or 802.11g with a stock antenna might have a range of 32 m (120 ft) indoors and 95 m (300 ft) outdoors. Range also varies with frequency band. Wi-Fi in the 2.4 GHz frequency block has slightly better range than Wi-Fi in the 5 GHz frequency block. Outdoor range with improved (directional) antennas can be several kilometres or more with line-of-sight.

Wi-Fi performance decreases roughly quadratically as the range increases at constant radiation levels.

Buckler

A buckler (French bouclier 'shield', from old French bocle, boucle 'boss') is a small shield gripped in the fist -- it was generally used as a companion weapon in hand-to-hand combat during the Middle Ages, as its size made it poor protection against missile weapons (e.g., arrows) but useful in deflecting the blow of an opponent's sword or mace. There are two major forms of medievally documented bucklers. The first is a simple round shield with the fist positioned directly behind the boss with a variety of shapes of face and depths of rim. These could also have projections from the top and bottom as in Hans Talhoffer's Fechtbücher or serrated rings around the boss as in one example in the Wallace Collection. The second major form is a corrugated rectangle as suggested by Achille Marozzo in his Opera Nova.