Cartesian coordinate system(UK: /kɑːˈtiːzjən/, US: /kɑːrˈtiʒən/) in a plane is a coordinate system that specifies each point uniquely by a pair of numerical coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, measured in the same unit of length. Each reference line is called a coordinate axis or just axis (plural axes) of the system, and the point where they meet is its origin, at ordered pair (0, 0). The coordinates can also be defined as the positions of the perpendicular projections of the point onto the two axes, expressed as signed distances from the origin.
mimeograph
A mimeograph machine (often abbreviated to mimeo, sometimes called a stencil duplicator) is a low-cost duplicating machine that works by forcing ink through a stencil onto paper.[1] The process is mimeography. A copy made by the process is a mimeograph.
Mimeographs, along with spirit duplicators and hectographs, were common technologies for printing small quantities of a document, as in office work, classroom materials, and church bulletins. Early fanzineswere printed by mimeograph because the machines and supplies were widely available and inexpensive. Beginning in the late 1960s and continuing into the 1970s, photocopying gradually displaced mimeographs, spirit duplicators, and hectographs.
escape velocity
The minimum speed an object without propulsion needs to have to move away indefinitely from the source of the gravity field.
USB Connectors
Connectors Type A and B
Comparison of USB connector plugs, excluding USB-C type plugs
The three sizes of USB connectors are the default or standard format intended for desktop or portable equipment, the mini intended for mobile equipment, and the thinner micro size, for low-profile mobile equipment such as mobile phones and tablets. There are five speeds for USB data transfer: Low Speed, Full Speed, High Speed (from version 2.0 of the specification), SuperSpeed (from version 3.0), and SuperSpeed+ (from version 3.1). The modes have differing hardware and cabling requirements. USB devices have some choice of implemented modes, and USB version is not a reliable statement of implemented modes. Modes are identified by their names and icons, and the specification suggests that plugs and receptacles be colour-coded (SuperSpeed is identified by blue).
Unlike other data buses (such as Ethernet), USB connections are directed; a host device has "downstream" facing ports that connect to the "upstream" facing ports of devices. Only downstream facing ports provide power; this topology was chosen to easily prevent electrical overloads and damaged equipment. Thus, USB cables have different ends: A and B, with different physical connectors for each. Each format has a plug and receptacle defined for each of the A and B ends. USB cables typically have male plugs on each end, and the corresponding receptacle is usually on a computer or electronic device.
Connectors Type C (USB-C)
Developed at roughly the same time as the USB 3.1 specification, but distinct from it, the USB-C Specification 1.0 was finalized in August 2014 and defines a new small reversible-plug connector for USB devices. The USB-C plug connects to both hosts and devices, replacing various Type-A and Type-B connectors and cables with a standard meant to be future-proof.
progressives
Progressive lenses, also called multifocal lenses, progressive addition lenses (PAL), varifocal lenses, progressive power lenses, graduated prescription lenses, or progressive spectacle lenses are corrective lenses used in eyeglasses to correct presbyopiaand other disorders of accommodation. They are characterised by a gradient of increasing lens power, added to the wearer's correction for the other refractive errors. The gradient starts at the wearer's distance prescription at the top of the lens and reaches a maximum addition power, or the full reading addition, at the bottom of the lens. The length of the progressive power gradient on the lens surface depends on the design of the lens, with a final addition power between 0.75 and 3.50 dioptres. The addition value prescribed depends on the level of presbyopia of the patient. In general the older the patient, the higher the addition.
proxy server
Communication between two computers (shown in grey) connected through a third computer (shown in red) which acts as a proxy server. Bob does not know to whom the information is going, which is the reason that proxies can be used to protect privacy.
In computer networking, a proxy server is a server application or appliance that acts as an intermediary for requests from clients seeking resources from servers that provide those resources. A proxy server thus functions on behalf of the client when requesting service, potentially masking the true origin of the request to the resource server.
Instead of connecting directly to a server that can fulfill a requested resource, such as a file or web page, the client directs the request to the proxy server, which evaluates the request and performs the required network transactions. This serves as a method to simplify or control the complexity of the request, or provide additional benefits such as load balancing, privacy, or security. Proxies were devised to add structure and encapsulation to distributed systems.
