Let Σ be a finite alphabet and let L1 and L2 be two languages over Σ. Assume you have access to two routines IsStringInL1(u) and IsStringInL2(u). The former routine decides whether a given string u is in L1 and the latter whether u is in L2. Using these routines as black boxes describe an efficient algorithm that given an arbitrary string w â Σ â decides whether w â (L1 + L2 )â. To evaluate the running time of your solution you can assume that calls to IsStringInL1 () and IsStringInL2 () take constant time. Note that you are not assuming any property of L1 or L2 other than being able to test membership in those languages.

Local area networks use many of the same network technologies and the internet, only on a smaller scale. devices that access lans are equipped with a network interface that contains circuitry for wireless or wired connections. devices also have a physical address, in addition to the ip addresses acquired from a dhcp server. the most popular wired technology is . the most popular wireless technology is , which can be configured as a(n) or star topology. setting up a lan and configuring its router is fairly easy. the first step is to change the standard to one that is secure. next, create a(n) that uniquely identifies the network by name. it is also important to activate wireless to prevent wireless signals from being intercepted during transmission. a limited-access network can be created for visitors to use. by activating , the router will be able to assign ip addresses to each device that joins the network. to connect to a secure lan that is protected by encryption, an encryption , or password, is required. lans can be used to access data collected by iot devices and the networks that tie these devices together. technologies such as rfid, nfc, bluetooth smart, zigbee, and z-wave offer -power links, essential for battery-powered devices that can’t expend excess amounts of energy transmitting data.