Advanced mobile phone system (AMPS) was a standard for analog cellular phone system developed by Bell Labs and officially introduced by AT&T in 1983.FeaturesIt is an analog system based on the initial electromagnetic spectrum allocation for cellular service by the Federal Communications Commission.It uses frequency division multiple access (FDMA) for ... Read More

Message switching is a connectionless network switching technique where the entire message is routed from the source node to the destination node, one hop at a time. It was a precursor of packet switching.ProcessPacket switching treats each message as an individual unit. Before sending the message, the sender node adds ... Read More

Circuit switching is a connection-oriented network switching technique. Here, a dedicated route is established between the source and the destination and the entire message is transferred through it.Phases of Circuit Switch ConnectionCircuit Establishment : In this phase, a dedicated circuit is established from the source to the destination through a ... Read More

The telephone system model is organized as a highly redundant, multilevel hierarchy. It comprises of the following components −Telephone of the subscriber or end userEnd office − Local central office directly connected to end user at a distance of 1 – 10km.Local loop − A two-way connection between the telephone ... Read More

Medium earth orbit (MEO) satellites lie between the two Van Allen Belts. MEOs are also called Intermediate Circular Orbits (ICOs).The altitudes of these satellites range from 2, 000 km to 35, 000 km, i.e. above the low earth orbits and below the geosynchronous orbits. The orbital periods of MEOs range ... Read More

You can use $lt operator for this. Let us create a collection with documents −> db.beforeSpecifyDateDemo.insertOne({"UserLoginDate":new ISODate('2016-03-21')}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd91e4de8cc557214c0e0d") } > db.beforeSpecifyDateDemo.insertOne({"UserLoginDate":new ISODate('2016-05-11')}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd91ecde8cc557214c0e0e") } > db.beforeSpecifyDateDemo.insertOne({"UserLoginDate":new ISODate('2017-01-31')}); {    "acknowledged" : true,    "insertedId" ... Read More

Let us create a collection with documents −> db.selectOnlyNumericDemo.insertOne({"UserId":"User101"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbdb711de8cc557214c0e16") } > db.selectOnlyNumericDemo.insertOne({"UserId":"102"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbdb716de8cc557214c0e17") } > db.selectOnlyNumericDemo.insertOne({"UserId":"User103"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbdb71dde8cc557214c0e18") } > db.selectOnlyNumericDemo.insertOne({"UserId":"104"}); {    "acknowledged" : true, ... Read More

You can use every() in MongoDB for this. Let us create a collection with documents −> db.arrayConditionDemo.insertOne({"Name":"John", "Marks":[40, 43, 45]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbdbd06de8cc557214c0e1a") } > db.arrayConditionDemo.insertOne({"Name":"Mike", "Marks":[45]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbdbd17de8cc557214c0e1b") } > db.arrayConditionDemo.insertOne({"Name":"Chris", "Marks":[43, 45, 59, 69, 78, ... Read More

You can use printjson() or print() to get output of MongoDB shell script. Let us create an array of objects.Following is the query to create an array of objects.> var studentDetails=[{"StudentName":"John", "StudentAge":21},    {"StudentName":"Carol", "StudentAge":24}, {"StudentName":"David", "StudentAge":25}];Following is the query to get the output of Mongo shell script using printjson() ... Read More

Yes, Mongo shell treats numbers as float by default. To work it as int or any other type, you need to mention explicitly. You can use NumberInt() for this. The syntax is as follows −var anyVariableName= [NumberInt("yourValue1"), NumberInt("yourValue2"), .....N];Let us implement the above syntax in order to treat numbers as ... Read More