Selin KÖK-030070162 1st week answers

 

LOCAL AREA NETWORKING

(New/better)

Given lack of interest in LANs in the late 1960s and early 1970s, it is not surprising that researchers outside the corporate sector developed the first LAN technologies. For example, in 1971, David Farber of UC Irvine built the first operational LAN, which was based on a Token Ring technology. His LAN, transmitted at 2.3 Mbps, that is, 46 times faster than the ARPANET, itself a relatively fast wide area network .Farber designed a relatively high-speed network because he built a locally distributed computing system based on minicomputers. In other words, his system connected computers instead of terminals and distributed the processing over several machines. In 1973, Robert Metcalfe at Xerox PARC developed the second major LAN type, Ethernet. Ethernet used a fundamentally different topology and transmission and access method, but it transmitted at a similar speed, namely 2.94 Mbps. Like Farber, Metcalfe needed the high networking speed because he built a distributed computing system, but unlike the system of Farber, PARC's system was based on connecting Xerox Alto personal workstations. PARC commissioned the development of a LAN because it needed the means to link the Alto computers with laser printers, which were the output devices for its “office of the future.” With this distributed computing system, based on personal computers and intended for the office use, PARC had invented what eventually became the dominant environment in which LANs would be deployed . LANs were initially used to connect minicomputers and to switch terminals to a host computer, but the LANs' main application would eventually be the connection of personal computers (that, is, IBM PCs) in the office environment. This client/server architecture would overthrow minicomputers and time-shared systems.

 (old)

A network is a linking of a group of computers to communicate with each other and share software and hardware recources via the cables and interfaces that connect the computers and peripherals. Application software used in a network allow several users access the same program and data at the same time. As the name implies, a Local Area Network or LAN is a system that covers short distances. Usually LAN is limited to a single department or a single building or a single campus. Typical data tranmission speeds are one to 100 megabits per second.

(P. Radhakrishan, S. Subramanyan, V. Raju, CAD/CAM/CIM, Second edition, p.526)

THREE DIMENTIONAL PRINTING

(new/better)

3D printing (3DP) is an RP process that functions by the deposition of powdered material in layers and the selective binding of the powder by a modulated ‘ink-jet’ printing of a binder material. Recently, 3DP has been reported to be capable of creating a surface of controlled macro-textures with high geometric complexity with no reduction in bulk mechanical strength of the material, which makes it a promising alternative to current manufacturing techniques for surface textures. Designing millimeter or sub-millimeter surface textures for 3DP, nevertheless, is difficult due to complex macro-structure of the tiny texture geometry as it needs to be compatible with the non-traditional manufacturing method of 3DP.

(H.J. Jee, E. Sach , A visual simulation technique for 3D printing,P2)

(old)

3D Printing

One of the most advanced printing technologies involves 3D printing. There are several types of 3D printers, including nano printers for printing on the nano scale. There are 3D printers that print various types of materials. You will find printers that use plastic, powder, and paper even cholate and sugar. The possibilities are endless when you think about the types of materials you can use for 3D printing. 3D printers are available in all shapes and sizes. Some take up an entire room, and some can be easily placed on your desktop.

(Singh S., Begining Google Sketchup for 3D Printing, 2010, p.XVI)