FML2004 1

Information about FML2004 1

Published on May 2, 2008

Author: Melinda

Source: authorstream.com

Content

Slide1:  2004 Faraday Memorial Lecture B.L.Deekshatulu ISRO Visiting Professor Univ. of Hyderabad 22 September’04 MULTIPLE FACETS OF ELECTRICAL ENGINEERING* * Presentation made from Literature / Internet survey - meant to serve as reading material. Contents:  Contents Brief on Faraday, Pioneers in EE and growth of IEEE Multiple Facets of EE Advances in Science & Technology, Bionics, Computers, Digital Signal Processing and Digital Image Processing. Discovery of Electricity:  Discovery of Electricity Electricity wasn't discovered in a single day. Thousands of great scientists from every corner of the planet have been exploring its effects, and its uses, for centuries. Of course, there's still much we don't know about the subject. There's so much more to learn in the future. But first let's look back and find out about the pre-20th century pioneers of electricity, and the people who first put it to practical use. Michael Faraday:  Michael Faraday 1820 , Developed the first electrical generator and the first electrical motor. Current is passed through a wire that is dipped in mercury (a conductive liquid) with a bar magnet in it. The current interacting with the magnet, according to basic principles of physics, causes the wire to rotate. 1831 , Formulated the induction law and creates thereby the theoretical bases to the building of transformers. Faraday’s Electric Motor About Faraday (Contd…):  About Faraday (Contd…) In 1826 Michael Faraday inaugurated the Christmas Lectures for young people at the Royal Institution, Albemarle St, London. One of the most famous of these lectures was on The Chemical History of a Candle, given by Faraday in 1860. Actually a series of six talks, the breadth of interest and the variety of observations and phenomena which Faraday brings in to the subject remain astonishing a century and a half later. The note-taking was by (Sir) William Crookes, co-discoverer of the element Thallium. Lecture 1: A Candle: The Flame - Its Sources - Structure Mobility - Brightness Lecture 2:  Brightness of The Flame - Air Necessary For Combustion - Production of Water Lecture 3:  Products: Water From The Combustion - Nature of Water - A Compound - Hydrogen Lecture 4: Hydrogen in The Candle - Burns Into Water - The Other Part of Water - Oxygen Lecture 5: Oxygen Present in The Air - Nature of The Atmosphere - Carbonic Acid Lecture 6: Carbon or Charcoal - Coal Gas - Respiration and Its Analogy to A Candle Source: http://www.fordham.edu/halsall/mod/1860Faraday-candle.html About Faraday (Contd…):  About Faraday (Contd…) It was characteristic of Faraday's devotion to the enlargement of the bounds of human knowledge that on his discovery of magneto-electricity he abandoned the commercial work by which he had added to his small salary, in order to reserve all his energies for research. This financial loss was in part made up later by a pension of 300 pounds a year from the British Government. Source: http://www.fordham.edu/halsall/mod/1860Faraday-candle.html Pioneers of EE:  Pioneers of EE Thales (600) Greek philosopher and mathematician wrote down many observations about his ability to "charge" and "discharge" electrostatic forces in a piece of amber by rubbing with cloth (dry friction). The ancient Greeks called amber – ‘Elektron’. AMBER Pioneers of EE ( 1540 to 1603 ):  Pioneers of EE ( 1540 to 1603 ) William Gilbert First to figure out that the compass worked by magnetics, not electrostatics. Coined the word "electricity," coming from the Greek word for "amber." Pioneers of EE (1700 to 1800):  Pioneers of EE (1700 to 1800) Pieter van Musschenbroek ( Leyden, Holland ) ( 1746 ) Began thinking of electricity as an invisible fluid and tried to capture and store it. Wrapped a water-filled jar with metal foil and discovered that this simple device could store the energy produced by an electrostatic generator. Benjamin Franklin ( 1752 ) Attempted to show that lightning was electrical in nature using a kite with a metal key attached to it . The words "conductor","insulator“, "charge“, "discharge“, "battery“, "shock","positive" and "negative" are all credited to Ben Franklin. A Leyden jar Pioneers of EE (1800 to 1900 ):  Pioneers of EE (1800 to 1900 ) Samuel Morse ( 1844 ) Although Morse is often credited with inventing the telegraph, his greatest contribution was actually Morse Code, a special language designed for the telegraph. Samuel Morse’s telegraph key Pioneers of EE (1800 – 1900):  Pioneers of EE (1800 – 1900) James Prescott Joule (1818-1889)  Born into wealth, James Prescott Joule's father built his son a complete laboratory when he finished his studies in England. There he established "Joule's Law", stating that when electricity is delivered through a metallic conductor, the heat generated is proportional to the resistance of the conductor multiplied by the square of the "electrical intensity". As a result of his groundbreaking work, we have the basic unit of energy - "The Joule". Did U Know? James Joule's first exposure with physics came when he worked at his family's brewery?  Working to replace the brewery's steam engines with electric motors, Joule became interested in working with electrical devices. Pioneers of EE (1800 to 1900):  Pioneers of EE (1800 to 1900) James Clerk Maxwell (1831-1879)  Born in Scotland, mathematician James Clerk Maxwell is one of the fathers of electrical communications. He envisioned a vast sea of space - called "The Ether" - through which light and heat traveled to earth as waves at the speed of light. His early discovery is the basis of other inventions including the radio, radar, mobile phones and television. Discovered Electromagnetic theory of light and the laws of electrodynamics. Did you know that in 1846, when Maxwell was only 14, he wrote a mathematical paper that was read to the Royal Edinburgh Society.  Source : http://www.powerzone.net/en/html/access/ac0.html/PowerZone!Pioneers of Electricity.htm Pioneers of EE (1800 to 1900):  A replica of Nikola Tesla's AC motor Pioneers of EE (1800 to 1900) Thomas Edison ( 1882 ) , Invention of incandescent electric lamp. Nikola Tesla ( 1888 ) A C Bell, Alexander Graham (1875 ) Invention of Telephone Pioneers of EE (1900 to 1950) :  Pioneers of EE (1900 to 1950) Marconi & De Forest Worked to create radio broadcasting. Bardeen & Brittain (Bell Labs ) Invented the transistor. Atanasoff & Clifford Berry (ABC) Laid foundations of modern digital computing. De Forest's "Audion" Audio Amplifier Tube Atanasoff’s vacuum tube Pioneers of EE (1950 to Today ):  Pioneers of EE (1950 to Today ) 1953 The concept of the radio was expanded to broadcast images as well, giving rise to the television. 1954 Bell Labs discovered how to utilize the photoelectric effect in electrical circuits to produce energy and the solar cell is invented. Kilby & Noyce (1959) Developed the Integrated Circuit. Intel (1971) Creates the first microprocessor. Integrated circuitry on a wafer The Intel 4004 microprocessor Slide16:  IEEE = A.I.E.E. + I.R.E Located in USA, but encompasses 150 countries – a global village. Aims – Meet & Share Multi – Disciplinary approach / explanation of complex problems (Ex: Biology , Cognitive Science, Electrical, Electronics, etc.) is the need of the hour. No: of Publications – about 90 Growth of IEEE Bionics:  Bionics BIOMEDICAL CIRCUITS AND SYSTEMS: A NEW WAVE OF TECHNOLOGY The recent years have seen an explosive growth of research applied to medical problems in the areas of life sciences, physical sciences and engineering. Such activities require inter-disciplinary collaboration between scientists, engineers, medical researchers, and practitioners to solve complex real world problems. BIOLOGY + ENGINEERING, BIONICS (MEDICAL), BIONICS (ENGINEERING) Source: IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS Electricity and the Body - History:  Electricity and the Body - History Did you know that electricity flows through your body? Luigi Galvani was the first to discover this with his frog experiments around 1780. Throughout the period from the late 1700s to the middle 1900s, scientists and doctors, such as Guillaume Duchenne, used batteries and small generators in an attempt to use electric currents to cure disease. They called this electrotherapy. Unfortunately, they found very few reliable cures, but that didn’t discourage them and by the early 20th century scientists figured out how to measure the body’s own electrical impulses. This turned out to be a very useful way to monitor the heart, brain, and other organs. One of the first to do this was Willem Einthoven. He developed the electrocardiograph to measure electrical current in the heart as it beats. We still use this device today. It’s called an EKG. Earl Bakken’s prototype pacemaker was first used in 1958. It was used on patients whose hearts failed to begin beating after surgery. Courtesy: Bakken Library and Museum Source: http://www.ieee-virtual-museum.org Bionics (medical):  Bionics (medical) Bionics means the replacement or enhancement of organs or other body parts by mechanical versions. Bionic implants differ from mere prostheses by mimicking the original function very closely, or even surpassing it. Bionics takes a somewhat broader scope in that it tries to develop engineering solutions from biological models. This approach is motivated by the fact that biological solutions will always be optimized by evolutionary forces. A classical example is the development of dirt- and water-repellent paint (coating) from the observation that the surface of the lotus flower plant is practically unsticky for anything (lotus effect). While the technologies that make bionic implants possible are still in a very early stage, a few bionic items already exist, the best known being the cochlear implant, a device for deaf people. Some versions come quite close to "normal" hearing; they can even work better than natural ears at background noise filtering. By 2004 fully functional artificial hearts have been developed. Significant further progress is expected to take place with the advent of nanotechnologies. A well known example of a proposed nanodevice is a respirocyte, an artificial red cell, designed (though not built yet) by Robert Freitas. Source: http://en.wikipedia.org/wiki/Bionics_(medical) Bionics (engineering):  Bionics (engineering) Bionics is application of biological analogies for the study and design of engineering systems. Specifically, it is a creativity technique that tries to use biological prototypes to get ideas for engineering solutions. This approach is motivated by the fact that biological organisms and their organs have been well optimized by evolution. Examples of bionics results in engineering include hulls of boats imitating the skin membrane of dolphins, sonar, radar and medical ultrasound imaging imitating echolocation of bats, non-stick coating imitating lotus effect. In the field of computer science, bionics approach has produced Cybernetics, Artificial neuron, Artificial Neural Networks, Swarm intelligence. Evolutionary computation was also motivated by bionics idea but it took the idea further by simulating evolution 'in silico' and producing well optimized solutions that had never appeared in nature. Often bionics approach emphasizes imitation of a biological/Organic structure rather than a mere implementation of the same function. For example, in computer science, cybernetics tries to model actual organic structures that make us intelligent, while artificial intelligence tries to model the intelligent function regardless of the particular way it can be achieved. A less common and maybe more recent meaning of the term "bionics" refers to merging organism and machine. This approach results in a hybrid systems combining biological and engineering parts, which can also be referred as cybernetic organism (cyborg). Source: http://en.wikipedia.org/wiki/Bionics_(engineering) Bionic Ears and The Cochlear Implant::  Bionic Ears and The Cochlear Implant: The human ear is made up of thousands of hair cells : when stimulated by sound they vibrate, passing electrical impulses on to the auditory nerve fibers. In the Bionic ear a lead of electrodes(20) is implanted in the ear to replicate the function of hair cells and stimulate the cochlea. Each electrode is tuned to different frequencies and pitches. Although the implant is rather complex, and requires a network of microphone, receiver, transmitter, and processor, the concept behind it is simple. Source: http://www.cem.msu.edu/~cem181fp/brain/page2.html Slide22:  Source: http://www.cem.msu.edu/~cem181fp/brain/page2.html Bionic Ears and the Cochlear Implant: Bio-Electronic Vision:  Bio-Electronic Vision Artificial Eye : For getting benefit from an enhanced vision system, the image must be adopted to the particular blind areas and areas of poor sensitivity. The information arriving at the eye must be shifted instantaneously to these areas. The thrust of all prosthetic vision devices is to use an electrode array to give the user perceptions of points of light that are correlated with the outside world. To achieve the expected shift of the image across the stimulating electrode array, the camera capturing the image must follow the wearer’s eye or pupil movements, by monitoring the front of the eye under infra-red illumination. Source: http://www.spectrumieee.org/publicaccess/9605teaser/9605vis2.html Slide24:  Source : Copyright 1996, The Institute of Electrical and Electronics Engineers, Inc. Bio-electronic Vision Slide25:  Digital Signal Processing Gabor Filters Wavelets Slide26:  Gabor Filter - Motivation Time (t) / Spatial (x) domain and frequency domain are two separate domains related by the Fourier Transform. The Fourier Transform of a Short duration pulse is a wide spread sinc function. The Fourier Transform of a long duration pulse is a short sinc function. The Fourier Transform of a Gaussian function of the form of e is also Gaussian. Fourier Transform of e multiplied by the Gaussian will be a shifted Gaussian at wc in the frequency domain. Thus, Gabor Filter helps in correlating a localised time domain signal with its corresponding frequency content. -x2 2 2 -jwcx GABOR FILTER BANK:  GABOR FILTER BANK Original Face Image w = p/2 s = p w = p/4 s = p w = p/8 s = p Note that the highest frequency (p/2) response occurs at thin edges, medium frequencies (p/4) at strong edges, and low frequencies (p/8) in the more uniform regions w corresponds to central frequency and s = p corresponds to one octave in Log scale. FFT (for comparison) Slide28:  The idea in this slide is to show the differences between FFT and Gabor Filters Note that Gabor Filter response is localized, i.e., it responds only in those locations in the image where such frequencies are present In FFT, only the frequency content is present with no information about where such frequencies are present A value of w =  corresponds to the highest frequency present in the image. It represents patterns that change from one pixel to the next. A value of w = /2 corresponds to patterns that change every two pixels, and so on.) GABOR FILTER BANK WAVELETS:  WAVELETS Wavelets are small waves Basic idea: approximate a signal as a sum of scaled and translated versions of a wavelet What do we gain? Frequency information at different locations WAVELETS:  WAVELETS If a signal has high frequency, one has to sample it at twice the highest frequency for reconstruction – this needs lot many samples. Using wavelets one can obtain the decomposition in a few steps. Use of Wavelets:  Use of Wavelets = + + = + DIGITAL WATERMARKING (DW):  DIGITAL WATERMARKING (DW) Adding information to protect copyright, to authenticate, to prevent misuse, abuse, etc. E.g., logos, trademarks, secret messages Applications Digital documents, art galleries, E-commerce, etc. LSB EXAMPLE:  LSB EXAMPLE Original Watermarked Watermark Innovations in Electrical Engineering:  Innovations in Electrical Engineering Advances:  Advances Quantum Computing Refers to transferring the (Q.M) state of one atomic or sub-atomic particle to another over a distance without direct physical contact. Those states – ex : Energy levels of electrons around the nucleus – can be used like the on - off states of Transistors to encode information and do computation. Existence of atoms & particles in two different states simultaneously is in Quantum physics. However, only one state manifests upon measurement. Computers storing data as quantum states can calculate along many parallel paths simultaneously. Ex : Factoring of large numbers (in cryptography). Source: IEEE Spectrum Sep’04 Quantum Computing (Contd…):  Quantum Computing (Contd…) Entanglement occurs when one state is observed fixing it to a particular state , the other state is instantaneously fixed into a related state independent of the distance between the two states. Australia and USA have shown how to teleport the properties of one atom to another. This could move the results of a calculation from one area of the computer to another – computer’s wiring. Photons rarely interact with each other and are not held in place. Atoms & ions are superior in computational systems because they can be fixed in place and manipulated with lasers. Photons are carriers of information from one atom to another atom. For making measurements on atoms, we need photons to change the state of atoms. Source: IEEE Spectrum Sep’04 Advances:  Advances Cold Fusion Revived – Generating Thermo-nuclear energy using tabletop apparatus Starting with Stanley Pons and Martin Fleischmann , the much sought after attempts include achievement of cold fusion using a battery connected to palladium electrodes immersed in a bath of heavy water . The fact that two deuterium nuclei can be fused at room temperature (which otherwise needs millions of OC) should pave a way to future work in this direction. The principle here is, to generate high pressure system through cavitation for fusion. Source: IEEE Spectrum Sep’04 Cold Fusion Revived – (contd…):  Cold Fusion Revived – (contd…) Generating Thermo-nuclear energy using tabletop apparatus. Further, that cold fusion can be achieved when a current is passed through palladium electrodes placed in heavy water. Such ideas of table top fusion could produce unlimited low-cost , clean energy. Two palladium electrodes within heavy water connected to a power source Source: IEEE Spectrum Sep’04 Advances:  Advances A Nuclear Micro-generator – Converting Radioactivity into Electricity In wrist worn GPS receivers or match box sized digital cameras or pocket size PCs , batteries occupy significant volume. The functioning of the battery today is same as that 200 years ago when the Italian physicist Volta sandwiched zinc & silver disks to create chemical battery, and used it to make a frog’s leg kick. For MEMS , we need smaller & long lasting power sources. The nuclear micro-generator is not a miniature reactor (Fission or Fusion ). All energy comes from high energy particles spontaneously emitted by Radioactive elements. Such batteries use thin radioactive films that pack in energy at densities thousands of times greater than Lithium-Iron batteries. Piezoelectricity is the means of power generation. Ex : Ni – 63 or Tritium. Nuclear batteries can pack in energy at densities thousands of time greater than those of Lithium-ion batteries. Source: IEEE Spectrum Sep’04 Advances:  Advances 1 2 A Nuclear MicroGenerator Beta particles (high-energy electrons) fly spontaneously from the radioactive source & hit the copper sheet, where they accumulate. Copper sheet gets charged negatively Electrostatic attraction between the copper sheet and the radioactive source bends the silicon cantilever and the piezoelectric plate on top of it Source: IEEE Spectrum Sep’04 Advances:  Advances 3 4 A Nuclear MicroGenerator When the cantilever bends to the point where the copper sheet touches the radioactive source, the electrons flow back to it, and the attractive force ceases The cantilever then oscillates, and the mechanical stress in the piezoelectric plate creates an imbalance in its charge distribution, resulting in an electric current Source: IEEE Spectrum Sep’04 Advances in EE :  Advances in EE Physicists, Electrical Engineers & Chemists worked in Nanolithography to etch only a few atoms wide on silicon substrates. Hot electrons from a scanning tunneling microscope are the etching tool. The substrate can be passivated by pure atomic hydrogen or with Deuterium. But needed 100 times the number of hot electrons. Passivating with Deuterium is for better radiation hardening. Source: IEEE Spectrum Nov’96 Slide43:  Source: IEEE Spectrum Nov’96 Biological Intelligence:  Biological Intelligence Marriage of Electrical Engineers with Chemistry. How the Brain works – From molecular to Cognitive level. - How the nerve cells operate & how the brain perceives the world. - Admixture of Engineers & Physical Scientists , Psychologists. - Goes beyond instrumentation to studying the brain Miniature nuclear magnetic resonance for studying metabolic activity at the cellular level. Conventional NMR uses pulsed RF fields to simulate nuclear transitions that reflect the structure & dynamics of molecules (actual molecules to resonate) To do NMR microscopy for individual cells , we need to shrink the coil to the size of the cells. Source: IEEE Spectrum Nov’96 Biological Intelligence (contd…1):  Biological Intelligence (contd…1) The Beckman institute has developed a Solenoid smaller than the diameter of the Human hair (100 μm) with 5 – 10 turns of a copper wire 12 – 25 μm thick. The tiny coil is formed around a capillary tube holding only a few Pico grams of the material under study Some of the key chemicals in single neurons can be identified The goal is to have an entire NMR on a chip in a little micro – probe. Studies help the researchers in linking chemical & electrical activity in local regions of the brain with higher cognitive functions – Ex: learning how to perform a task. Source: IEEE Spectrum Nov’96 Biological Intelligence (contd…2):  Biological Intelligence (contd…2) Human Being as a machine or vice-versa Human - Computer intelligence interaction – needs image formation and analysis , Robotics , Speech recognition , hardware & software. The robot cockroach is an example. The cockroach remained unchanged over ages – local minima in evolution. The insect’s legs were co-ordinated through a central nervous system based on DSP chips. When powered up this creature heaves itself to a third of a meter height and resists pressure for pressing down on its back. A great deal of intimate knowledge of cockroach’s body, biological control & nervous system are required. Source: IEEE Spectrum Nov’96 Slide48:  A walking robot modeled on a cockroach was the brain child of an engineer, an entomologist, and a neurobiologist. By modeling the robot on the physiology of an insect, they gave the machine such desirably characteristics as agility, a low center of gravity, independently controlled legs, and the ability to function even after suffering damage. Source: IEEE Spectrum Nov’96 Human Body as a Computer Bus:  Human Body as a Computer Bus Patented by Microsoft for the method & the apparatus for transmitting power & data using the Human body. For creating a Personal Area Network (PAN), one has to link the device (Mobile phone or pager) using infrared or radio signals - No large power source, and minimal interference. Microsoft is suggesting to use ones own skin conductive properties to transmit the data to create such a network. A wide variety of living animals could be used to create computer buses. The keypad might be a persons forearm. The physical resistance offered by the human body can be used as implementing a key pad as well as estimating distances between devices – you can type on your skin. Source: IEEE India Bulletin Sep. 04 Advances in Communications:  Advances in Communications Broadband over power lines (Power line communications) Existing since 1950s. New boom to Digital Subscribers & Internet services. (minimum 10 Megabits/sec). Attach a Wi-Fi port to the power line modem. Intellon’s chip sets ( Intelligent router) combine orthogonal frequency division modulation, dozens of carrier channels and automatic channel switching. Advantage : Data suffers less loss Amperion Inc. Current Technologies use a device that serves as a direct link between an overhead medium voltage line and the line running to a house. Advantage : Data packets can avoid the transformers that step down the voltage destroying the data. Source: IEEE Spectrum Sep’04 Advances in Communications:  Advances in Communications Broadband over power lines (Power line communications) Problems : Noise Interference with other Radio signals (Hams & Aircraft operators). One way to reduce interference is trying to notch out Ham frequencies. Bridge : A Device mounted on power line poles to make data by-pass transformers. Source: IEEE Spectrum Sep’04 Advances in Communications :  Advances in Communications Ability of Electrons to carry more information - use of fewer electrons for a given function. Modern cell phones Integrate Phone, GPS, Camera, Computer GSM – One band for each cell at any point of time. TDM is used. CDMA Systems – Packetized Message. Uses spread spectrum techniques (Chirp). The digital code is for each user – for easy decoding. Operating Systems Specific to mobile Encryption methods – shorter & faster codes X to Ku , Ka Bands – Pointed / Narrower beam (more gain). Foot print is small. Voice over Internet Protocol (VOIP) :  Voice over Internet Protocol (VOIP) In normal telephone (300 – 3khz) the channel capacity is not fully utilized. IP uses the internet infrastructure for its own data. In IP the data is not handled on a fixed path. We use the channel capacity well because of packet switching. So, convert the analog voice signal into digital data and then into IP packets to transmit to the other side through the Ethernet \ Internet. Normally, the basic cost of long distance call will be the local call cost at each place plus dedicated international circuit cost. In VOIP, the cost of creating a dedicated circuit will not come in. Slide55:  Keyhole surgery Keyhole surgery is now considered the treatment of choice for a wide range of problems such as the gallbladder, spleen, adrenal glands, uterus and ovaries. Miniature instruments : a tiny cauterizing unit, a mini-video camera, a light introduced through a fiber optic tube keyhole surgery requires a smaller incision than traditional methods The keyhole method is also giving patients a much quicker fix than before. Biomedical Innovations:  Biomedical Innovations Ageing & Technology Scientists have developed a sophisticated enough understanding of the nature of human Ageing to begin seriously planning ways to defeat it. These are guided by the notion that the body is a failure - prone, defect - ridden machine, formed through the stochastic process of biological evolution. Reliability engineering (which was developed in the late 1950s to describe the failure & Ageing of complex electrical and electronic equipment ) is the backbone for these studies. It is assumed that the human, like machines is made up of redundant components, many of which are defective right from the birth. For a given function, number of neurons get connected and work together. The Human body starts with imperfect parts . It can start failing in 0–5 years (Death rate higher). Ageing starts from the age of about 11 years. The risk of death increases exponentially, doubling every eight years. Ageing is defined through the increased risk of failure with the passage of time. Source: IEEE Spectrum Sep’04 Biomedical Innovations:  Biomedical Innovations Ageing & Technology (contd…1) B. Gompertz in 1825 observed that the logarithm of death rates increase linearly with age – this was used in life insurance business. This does not hold beyond 100 years. Weibull , Swedish engineer & mathematician observed that the logarithm of failure rates increases linearly with the logarithm of age. Recent experiments on neuro – degenerative diseases (Ex : Parkinson) indicate brain - cell death stays constant regardless of age. Many cell functions, too, have been shown to be as good as new even in old age. Source: IEEE Spectrum Sep’04 Biomedical Innovations:  Biomedical Innovations Ageing & Technology (contd…2) Mathematics of Reliability Theory predicts that a system may deteriorate with age even if it is built from non – ageing elements i.e. elements that have a constant rate of failure. This applies to any system made up of redundant but irreplaceable parts. Standard Reliability model usually have a hidden assumption that the system at start is undamaged. However, for humans it is the reverse - Organisms start their adult life with a high load of initial damage. Observations: Female human Fetus at 4 – 5 months possesses 6 – 7 million eggs. At the time of birth , this number drops to 1-2 million. At the start of puberty in normal girls there are only 0.3 – 0.5 million eggs left (5 – 7 % of initial). Menopause and the failure of the reproductive system is due to exhaustion of the number of eggs over time. Source: IEEE Spectrum Sep’04 Biomedical Innovations:  Biomedical Innovations Ageing & Technology (contd…3) Source: Spectrum Sep’04 Biomedical Innovations:  Biomedical Innovations Ageing & Technology (contd…4) Source: Spectrum Sep’04 Biomedical Innovations:  Biomedical Innovations Ageing & Technology (contd…5) Source: Spectrum Sep’04

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