Memristor

Memristor is a short form for Memory + Resistor and it was predicted to be the fourth circuit element, way back in 1971, by Prof. Leon Chua, university of California, Berkley. Memristance is the property of an electronic component, whereby the resistance increases if the charge flows in one direction and it decreases if the charge flows in the opposite direction. If the flow of charge is stopped completely, then it will remember the last resistance that it had. If the flow of charge starts again, the resistance of the circuit will be what it was when it was last active! Memory banks built with memristors could be a thousand times faster than magnetic disk systems, while consuming a fraction of power. Such memristors could fuel a new class of computer memory that would remember, even if the machine is switched off. For such of those memristors, whose resistance varies quickly between a minimum and a maximum, we can think of a memristor as a switch.

Possible Applications:

1. Crossbar latches, which would probably replace transistors in future computers

2. Non-volatile solid state memory with greater data density than hard disks, with access times similar to DRAM’s

3. Programmable Logic

4. Signal Processing 5.Neural networks

6. Facial recognition technology

7. Improved security and privacy features that recognize a complex set of bio-metric features

Digital Image Processing

Digital image processing is any form of information processing for which the input is an image, such as photographs or frames of video; the output of image processing can be either an image or a set of characteristics or parameters related to the image. Most image-processing techniques involve treating the image as a two-dimensional signal and applying standard signal-processing techniques to it. Modern digital technology has made it possible to manipulate multi-dimensional signals with systems that range from simple digital circuits to advanced parallel computers. The goal of this manipulation can be divided into three categories:
• Image processing-image in image out.
• Image analysis-image in measurements out.
• Image understanding-image in high level description out.


Image processing is the use of computer algorithms to perform image processing on digital images. Digital image processing has the same advantages over analog image processing as digital signal processing has over analog signal processing. It allows a much wider range of algorithms to be applied to the input data, and can avoid problems such as the build-up of noise and signal distortion during processing. One of the most popular and interesting application of digital image processing is DIGITAL CINEMA. Most theaters played 35-mm film transfers of the movie, but some played it on digital movie projectors. As it turns out, the rise of digital cinema will have a pretty big effect on the world.

Klystron

Klystron is a microwave device which can be used for two purposes. Two cavity klystrons are used as amplifiers and reflex klystrons are used as oscillators .Another type of klystron known as Multicavity klystron bear many re- entrant cavities. A two cavity klystron comprises of a buncher cavity and catcher cavity. The electrons ejected from the cathode are accelerated and focussed by focussing anodes. The beam of electrons then passes through the buncher cavity gap. The electrons travel with the same constant velocity when they pass the cavity gap during zero cavity voltage. When they enter the cavity gap during positive half cycle of the gap voltage, the electrons are accelerated and move with a greater velocity. Similarly when they are travelling during the negative half cycle of the gap voltage, the electrons are decelerated and their velocity is reduced. Finally the electrons after passing through the catcher cavity are collected by the collector which is biased by collector voltage. In case of reflex klystron, there is only one cavity. When the electrons are ejected from the cathode, similar to two cavity klystron, the bunching of electrons occurs as they pass through the gap of the cavity. The electron beam is then repelled by the repeller which is given a negative potential. The repeller repels the electrons towards the cavity and they are collected at the walls of the cavity. The microwave output can be obtained from the walls of the cavity. A high electromagnetic field is created in the cavity of reflex klystron.

Heart Attack Detection

More than 25 million people suffering from heart attack die before reaching the hospital, more than 50% people die waiting for more than 2 hours before getting help. These deaths are mainly due to the lack of proper methodology for early diagnosis of heart attack. The detection of heart attack using bio sensor detects troponin, a protein component present in skeletal and cardiac muscles. Early detection has long been viewed as a key to limiting the consequences of heart attacks. For example, the human body undergoes significant biochemical activity long before the physical symptoms of a heart attack begin. As blood flow decreases and cardiac tissue deadens, cells release natural chemicals, such as troponins. These chemicals can act as clear and specific chemical markers that indicate a heart attack is imminent. The Bio-Sensor transmits electrical signals which are transmitted through the GPS system to the physician to monitor the status of the patient. Cardiac markers are substances released from heart muscle when it is damaged as a result of myocardial infarction. Depending on the marker, it can take between 2 to 24 hours for the level to increase in the blood.
There are various markers for heart attack during its onset.
• Cardiac troponin (The most sensitive and specific test for myocardial damage)
• Creatine kinase (CK – also known as creatine phosphokinase or phosphocreatine kinase)
• Aspartate transaminase (AST – also called glutamic oxaloacetic transaminase (GOT/SGOT) or aspartate aminotransferase (ASAT))
• Lactate dehydrogenase (LDH)
• Myoglobin (Mb) has low speficity for myocardial infarction and is used less than the other markers.
The early detection of heart attack will save millions of people.

X.25 Packet switching network

Packet switching networks use X.25 protocols to determine the user network interface and the interior design of the network .Unlike frame relay ,the call control information in X.25 is sent through the same logical virtual circuit along with the user data .The multiplexing and demultiplexing is carried on layer 2 of X.25 .The layers 2 and 3 are responsible for flow control and error control mechanisms .X.25 produces a lot of overhead .For each hop in the network the data link control layer has to exchange both the data and the acknowledgment with each node .It is also necessary for the intermediate nodes to maintain a state table for each of the virtual circuits for call management ,flow and error control aspects .The advanced digital communication is based on highly reliable transmission links formed by optical fibers .These transmission links besides providing high speed also uses high data rate for transmission .The X.25 architecture consists of a physical layer which determines the nature of transmission medium and the transmission of bits using a specific coding technique .The Link Access Protocol Balanced (LAPB) layer provides a reliable data link control service and in the final layer of X.25 , packet level is used to define the virtual circuits .Several virtual circuits are guided by a LAPB pipe which provides the facilities for error control and flow control.