Robotics

A Robot is an electro-mechanical system programmed to perform variety of tasks. These are devices that use artificial intelligence and can react according to the sensory inputs. The essential characteristics of a Robot are mobility, programmability, sensors, mechanical capability and flexibility. Robotics deals with the study of robots and the technology involved in designing them .Nowadays Robots have become the integral part of every manufacturing industry and its applications are enormous .Robot design involves the work of an electronics engineer ,mechanical engineer ,software engineer and hence a lot of manpower is involved in designing it. The basic structure of a robot is mechanical .The chain is built of actuators, links, and joints which allow more degrees of freedom. Actuators form the muscles of a robot .Electric motors are the most popular actuators .The major components using which Robots are made are Motors ,Stepper motors ,Piezo motors ,Air muscles ,Electro active polymers ,Elastic nanotubes .Robots are very much useful is space navigation systems .The space craft’s meant for exploring the universe carries very high sensitive robots .These robots take pictures of the planet surface and hence are more useful for space exploration .They are also useful for defusing the bombs ,in nuclear reactors to control the nuclear reactions ,under water explorations and many other mechanical industries. We have flying robots, walking robots, talking robots ready to serve humanity.

Call Control in Frame Relay

Frame relay can have the multiple links over a single connection, like X.25. In frame relay the single link is called data link connection and the data transfer between the two end points involve the following stages
1. Connection establishment between the end users and assigning an unique Data Link Connection Identifier (DLCI) number.
2. User data frames are exchanged between the end points .The frame also contain the DLCI number to identify the right connection.
3. The final step is releasing the logical connection .Whenever a logical virtual connection is being established, exchanging the call control messages between the end users , the DLCI field set to zero. It has call control message on the information field of the frame relay .

The messages that are exchanged for connection establishments are
1. SETUP
2. CONNECT
3. RELEASE
4. RELEASE COMPLETE
Either side may send a SETUP message to establish a connection .On receiving the SETUP message the receiver will send a CONNECT message if it desires to create a connection else it will send a COMPLETE RELEASE message .After creating a connection the sender may assign a DLCI number or the receiver may assign after the CONNECT message. Either the sender or the receiver may end the connection by sending the RELEASE message .The other system must respond to that message by sending a RELEASE COMPLETE message.

Future of Nanotechnology

The future of technology is in some ways easy to predict. Computers will become faster, materials will become stronger, and medicine will cure more diseases. Nanotechnology, which works on the nanometer scale of molecules and atoms, will be a large part of this future, enabling great improvements in all these technologies. Advanced nanotechnology will work with molecular precision, building a wide range of products that are impossible to make today.

Molecular Machinery, Manufacturing and Computation are the development of productive nanosystems, in other words, nanoscale machinery able to build atomically precise products under digital control. Drawing inspiration from biology, this vision generalizes the nanomachinery of living systems and promises a broad set of productive capabilities with unprecedented power and equal opportunities and consequences.

The focus on productive nanosystems and large-scale molecular manufacturing processes will enable the extend range of what human beings can manufacture. Every manufacturing method is a method for arranging atoms. Most methods arrange atoms crudely even the finest commercial microchips are grossly irregular at the atomic scale, and much of today's nanotechnology faces the same limit. Chemistry and biology, by contrast, make molecules defined by particular arrangements of atoms always with the same numbers, kinds, and linkages. Chemists use clever methods to do this, but these methods do not scale up well. Biology, however, uses a different, more scalable methods in which, cells contain productive nanosystems “ribosomes” that use digital data “from genes” to guide the assembly of molecular objects “proteins” that they serve as parts of molecular machines. Molecular manufacturing will likewise use stored data to guide construction work did by molecular machines, greatly extending abilities in nanotechnology.

Congestion in network

A packet switch or a router consists of several input ports and output ports. One or more ports are connected to the neighboring nodes and zero or more ports are connected to the end system .Each port consists of two buffers viz, input buffer and output buffer .The input packets to the router is stored in the input buffer where the router decides the routing path and the output packets are stored in the output buffer before they are dispatched. Both the ports are either associated with equal size buffers or pool of memories to perform the buffering activities. Packets to the ports are stored in their corresponding input buffers .The incoming packets are examined and the routing decisions are made to choose the appropriate path and then the packets are moved to the appropriate output buffer .Packets queued for output are transmitted as rapidly as possible. If the packets’ to the port arrive very fast to process them or faster than the processing time then the buffer gets full .On such conditions appropriate decisions have to be made either to discard the arriving packets or to inform the previous nodes about the congestion so that the incoming data rate can be minimized .But here the output buffer of the previous node will get congested and hence the congestion propagates through the entire network.