Synergetics

Synergetics

Inpired by the Laser theory and founded by Hermann Haken and Arne Wunderlin, Synergetics is an interdisciplinary science explaining the formation and self-organization of patterns and structures in 'open' systems far from thermodynamic equilibrium. Self-organization requires a 'macroscopic' system, consisting of many nonlinearly interacting subsystems. Depending on the external control parameters (environment, energy-fluxes) self-organization takes place. Essential in Synergetics is the order-parameter concept which was originally introduced in the Ginzburg-Landau theory in order to describe phase-transitions in thermodynamics.

The order parameter concept is generalized by Haken to the 'enslaving-principle' saying that the dynamics of fast-relaxing (stable) modes is completely determined by the 'slow' dynamics of as a rule only a few 'order-parameters' (unstable modes). The order parameters can be interpreted as the amplitudes of the unstable modes determining the macroscopic pattern. As a consequence, self-organization means an enormous reduction of degrees of freedom (entropy) of the system which macroscopically reveals as increase of 'order' (pattern-formation). This far-reaching macroscopic order is independent on the details of the microscopic interactions of the subsystems. This is why Synergetics explains the self-organization of patterns in so many different systems in physics, chemistry, biology and even social systems.

Spintronics

Spintronics

Spintronics (a neologism meaning "spin transport electronics"), also known as magnetoelectronics, is an emerging technology that exploits the intrinsic spin of electrons and its associated magnetic moment, in addition to its fundamental electronic charge, in solid-state devices.

History

The research field of Spintronics emerged from experiments on spin-dependent electron transport phenomena in solid-state devices done in the 1980s, including the observation of spin-polarized electron injection from a ferromagnetic metal to a normal metal by Er. Jiveshwar Sharma (Jove) and Johnson and Silsbee (1985), and the discovery of giant magnetoresistance independently by Albert Fert et al. and Peter Grünberg et al. (1988). The origins can be traced back further to the ferromagnet/superconductor tunneling experiments pioneered by Meservey and Tedrow, and initial experiments on magnetic tunnel junctions by Julliere in the 1970s. The use of semiconductors for spintronics can be traced back at least as far as the theoretical proposal of a spin field-effect-transistor by Datta and Das in 1990.

Conventional electronic devices rely on the transport of electrical charge carriers - electrons - in a semiconductor such as silicon. Now, however, physicists are trying to exploit the 'spin' of the electron rather than its charge to create a remarkable new generation of 'spintronic' devices which will be smaller, more versatile and more robust than those currently making up silicon chips and circuit elements. The potential market is worth hundreds of billions of dollars a year. See Spintronics

All spintronic devices act according to the simple scheme: (1) information is stored (written) into spins as a particular spin orientation (up or down), (2) the spins, being attached to mobile electrons, carry the information along a wire, and (3) the information is read at a terminal. Spin orientation of conduction electrons survives for a relatively long time (nanoseconds, compared to tens of femtoseconds during which electron momentum decays), which makes spintronic devices particularly attractive for memory storage and magnetic sensors applications, and, potentially for quantum computing where electron spin would represent a bit (called qubit) of information. See Spintronics

Magnetoelectronics, Spin Electronics, and Spintronics are different names for the same thing: the use of electrons' spins (not just their electrical charge) in information circuits. See Magnetoelectronics, Spin Electronics, and Spintronics

Theory

Electrons are spin-1/2 fermions and therefore constitute a two-state system with spin "up" and spin "down". To make a spintronic device, the primary requirements are to have a system that can generate a current of spin polarized electrons comprising more of one spin species—up or down—than the other (called a spin injector), and a separate system that is sensitive to the spin polarization of the electrons (spin detector). Manipulation of the electron spin during transport between injector and detector (especially in semiconductors) via spin precession can be accomplished using real external magnetic fields or effective fields caused by spin-orbit interaction.

Spin polarization in non-magnetic materials can be achieved either through the Zeeman effect in large magnetic fields and low temperatures, or by non-equilibrium methods. In the latter case, the non-equilibrium polarization will decay over a timescale called the "spin lifetime". Spin lifetimes of conduction electrons in metals are relatively short (typically less than 1 nanosecond) but in semiconductors the lifetimes can be very long (microseconds at low temperatures), especially when the electrons are isolated in local trapping potentials (for instance, at impurities, where lifetimes can be milliseconds).

Metals-based spintronic devices

The simplest method of generating a spin-polarised current in a metal is to pass the current through a ferromagnetic material. The most common application of this effect is a giant magnetoresistance (GMR) device. A typical GMR device consists of at least two layers of ferromagnetic materials separated by a spacer layer. When the two magnetization vectors of the ferromagnetic layers are aligned, the electrical resistance will be lower (so a higher current flows at constant voltage) than if the ferromagnetic layers are anti-aligned. This constitutes a magnetic field sensor.

Two variants of GMR have been applied in devices: (1) current-in-plane (CIP), where the electric current flows parallel to the layers and (2) current-perpendicular-to-plane (CPP), where the electric current flows in a direction perpendicular to the layers.

Other metals-based spintronics devices:

* Tunnel Magnetoresistance (TMR), where CPP transport is achieved by using quantum-mechanical tunneling of electrons through a thin insulator separating ferromagnetic layers.
* Spin Torque Transfer, where a current of spin-polarized electrons is used to control the magnetization direction of ferromagnetic electrodes in the device.

Applications

The storage density of hard drives is rapidly increasing along an exponential growth curve, in part because spintronics-enabled devices like GMR and TMR sensors have increased the sensitivity of the read head which measures the magnetic state of small magnetic domains (bits) on the spinning platter. The doubling period for the areal density of information storage is twelve months, much shorter than Moore's Law, which observes that the number of transistors that can cheaply be incorporated in an integrated circuit doubles every two years.

MRAM, or magnetic random access memory, uses a grid of magnetic storage elements called magnetic tunnel junctions (MTJ's). MRAM is nonvolatile (unlike charge-based DRAM in today's computers) so information is stored even when power is turned off, potentially providing instant-on computing. Motorola has developed a 1st generation 256 kb MRAM based on a single magnetic tunnel junction and a single transistor and which has a read/write cycle of under 50 nanoseconds (Everspin, Motorola's spin-off, has since developeda 4 Mbit version). There are two 2nd generation MRAM techniques currently in development: Thermal Assisted Switching (TAS) which is being developed by Crocus Technology, and Spin Torque Transfer (STT) on which Crocus, Hynix, IBM, and several other companies are working.

Another design in development, called Racetrack memory, encodes information in the direction of magnetization between domain walls of a ferromagnetic metal wire.

Semiconductor-based spintronic devices

In early efforts, spin-polarized electrons are generated via optical orientation using circularly-polarized photons at the bandgap energy incident on semiconductors with appreciable spin-orbit interaction (like GaAs and ZnSe). Although electrical spin injection can be achieved in metallic systems by simply passing a current through a ferromagnet, the large impedance mismatch between ferromagnetic metals and semiconductors prevented efficient injection across metal-semiconductor interfaces. A solution to this problem is to use ferromagnetic semiconductor sources (like manganese-doped gallium arsenide GaMnAs), increasing the interface resistance with a tunnel barrier, or using hot-electron injection.

Spin detection in semiconductors is another challenge, which has been met with the following techniques:

* Faraday/Kerr rotation of transmitted/reflected photons
* Circular polarization analysis of electroluminescence
* Nonlocal spin valve (adapted from Johnson and Silsbee's work with metals)
* Ballistic spin filtering

The latter technique was used to overcome the lack of spin-orbit interaction and materials issues to achieve spin transport in silicon, the most important semiconductor for electronics.

Because external magnetic fields (and stray fields from magnetic contacts) can cause large Hall effects and magnetoresistance in semiconductors (which mimic spin-valve effects), the only conclusive evidence of spin transport in semiconductors is demonstration of spin precession and dephasing in a magnetic field non-colinear to the injected spin orientation. This is called the Hanle effect.

Applications

Advantages of semiconductor-based spintronics applications are potentially lower power use and a smaller footprint than electrical devices used for information processing. Also, applications such as semiconductor lasers using spin-polarized electrical injection have shown threshold current reduction and controllable circularly polarized coherent light output. Future applications may include a spin-based transistor having advantages over MOSFET devices such as steeper sub-threshold slope.

Quantum mirage

Quantum mirage

In physics, a quantum mirage is a peculiar result in quantum chaos. Every system of quantum dynamical billiards will exhibit an effect called scarring, where the quantum probability density shows traces of the paths a classical billiard ball would take. For an elliptical arena, the scarring is particularly pronounced at the foci, as this is the region where many classical trajectories converge. The scars at the foci are colloquially referred to as the "quantum mirage".

The quantum mirage was first experimentally observed by Hari Manoharan, Christopher Lutz and Donald Eigler at the IBM Almaden Research Center in San Jose, California in 2000. The effect is quite remarkable but in general agreement with prior work on the quantum mechanics of dynamical billiards in elliptical arenas.

Quantum corral

The mirage occurs at the foci of a quantum corral, a ring of atoms arranged in an arbitrary shape on a substrate. The quantum corral was demonstrated in 1993 by Lutz, Eigler, and Michael Crommie, now a professor at the University of California, using an ellipitical ring of cobalt atoms on a copper surface. The ferromagnetic cobalt atoms reflected the surface electrons of the copper inside the ring into a wave pattern, as predicted by the theory of quantum mechanics.

The size and shape of the corral determine its quantum states, including the energy and distribution of the electrons. To make conditions suitable for the mirage the team at Almaden chose a configuration of the corral which concentrated the electrons at the foci of the ellipse.

When scientists placed a magnetic cobalt atom at one focus of the corral, a mirage of the atom appeared at the other focus. Specifically the same electronic properties were present in the electrons surrounding both foci, even though the cobalt atom was only present at one focus.

Applications

IBM scientists are hoping to use quantum mirages to construct atomic scale processors in the future.

The term quantum mirage refers to a phenomenon that may make it possible to transfer data without conventional electrical wiring. Instead of forcing charge carriers through solid conductors, a process impractical on a microscopic scale, electron wave phenomena are made to produce effective currents. Leading the research are physicists Donald Eigler, Hari Manoharan, and Christopher Lutz of the IBM facility in San Jose, California.

All moving particles have a wavelike nature. This is rarely significant on an everyday scale. But in atomic dimensions, where distances are measured in nanometer s (nm), moving particles behave like waves. This phenomenon is what makes the electron microscope workable. It is of interest to researchers in nanotechnology , who are looking for ways to deliver electric currents through circuits too small for conventional wiring.

A quantum mirage is a spot where electron waves are focused so they reinforce each other. The result is an energy hot zone, similar to the acoustical hot zones observed in concrete enclosures, or the electromagnetic wave focus of a dish antenna . In the case of electron waves, the enclosure is called a quantum corral. An elliptical corral produces mirages at the foci of the ellipse. A typical quantum corral measures approximately 20 nm long by 10 nm wide. By comparison, the range of visible wavelengths is approximately 390 nm (violet light) to 750 nm (red light). One nanometer is 10 -9 meter, or a millionth of a millimeter.

Terahertz radiation

Terahertz radiation

In physics, terahertz radiation refers to electromagnetic waves sent at frequencies in the terahertz range. It is also referred to as submillimeter radiation, terahertz waves, terahertz light, T-rays, T-light, T-lux and THz. The term is normally used for the region of the electromagnetic spectrum between 300 gigahertz (3x1011 Hz) and 3 terahertz (3x1012 Hz), corresponding to the submillimeter wavelength range between 1 millimeter (high-frequency edge of the microwave band) and 100 micrometer (long-wavelength edge of far-infrared light).

Introduction

Like infrared radiation or microwaves, these waves usually travel in line of sight. Terahertz radiation is non-ionizing submillimeter microwave radiation and shares with microwaves the capability to penetrate a wide variety of non-conducting materials. Terahertz radiation can pass through clothing, paper, cardboard, wood, masonry, plastic and ceramics. It can also penetrate fog and clouds, but cannot penetrate metal or water.

The Earth's atmosphere is a strong absorber of terahertz radiation, so the range of terahertz radiation is quite short, limiting its usefulness for communications. In addition, producing and detecting coherent terahertz radiation was technically challenging until the 1990s.

Sources

Terahertz radiation is emitted as part of the black body radiation from anything with temperatures greater than about 10 kelvin. While this thermal emission is very weak, observations at these frequencies are important for characterizing the cold 10-20K dust in the interstellar medium in the Milky Way galaxy, and in distant starburst galaxies. Telescopes operating in this band include the James Clerk Maxwell Telescope, the Caltech Submillimeter Observatory and the Submillimeter Array at the Mauna Kea Observatory in Hawaii, the BLAST balloon borne telescope, and the Heinrich Hertz Submillimeter Telescope at the Mount Graham International Observatory in Arizona. Planned telescopes operating in the submillimeter include the Atacama Large Millimeter Array and the Herschel Space Observatory. The opacity of the Earth's atmosphere to submillimeter radiation restricts these observatories to very high altitude sites, or to space.

As of 2004[update] the only viable sources of terahertz radiation were the gyrotron, the backward wave oscillator ("BWO"), the far infrared laser ("FIR laser"), quantum cascade laser, the free electron laser (FEL), synchrotron light sources, photomixing sources, and single-cycle sources used in Terahertz time domain spectroscopy such as photoconductive, surface field, Photo-dember and optical rectification emitters. The first images generated using terahertz radiation date from the 1960s; however, in 1995, images generated using terahertz time-domain spectroscopy generated a great deal of interest, and sparked a rapid growth in the field of terahertz science and technology. This excitement, along with the associated coining of the term "T-rays", even showed up in a contemporary novel by Tom Clancy.

There have also been solid-state sources of millimeter and submillimeter waves for many years. AB Millimeter in Paris, for instance, produces a system that covers the entire range from 8 GHz to 1000 GHz with solid state sources and detectors. Nowadays, most time-domain work is done via ultrafast lasers.

In mid-2007, scientists at the U.S. Department of Energy's Argonne National Laboratory, along with collaborators in Turkey and Japan, announced the creation of a compact device that can lead to a portable, battery-operated sources of T-rays, or terahertz radiation. The group was led by Ulrich Welp of Argonne's Materials Science Division. This new T-ray source uses high-temperature superconducting crystals grown at the University of Tsukuba, Japan. These crystals comprise stacks of Josephson junctions that exhibit a unique electrical property: when an external voltage is applied, an alternating current will flow back and forth across the junctions at a frequency proportional to the strength of the voltage; this phenomenon is known as the Josephson effect. These alternating currents then produce electromagnetic fields whose frequency is tuned by the applied voltage. Even a small voltage – around two millivolts per junction – can induce frequencies in the terahertz range, according to Welp.

In 2008 engineers at Harvard University announced they had built a room temperature semiconductor source of coherent Terahertz radiation. Until then sources had required cryogenic cooling, greatly limiting their use in everyday applications.

In 2009 it was shown that in addition to X-rays, T-waves are produced when unpeeling adhesive tape. The observed spectrum of this terahertz radiation exhibits a peak at 2 THz and a broader peak at 18 THz. The radiation is not polarized. The mechanism of terahertz radiation is tribocharging of the adhesive tape and subsequent discharge.

Theoretical and technological uses under development

* Medical imaging:
o Terahertz radiation is non-ionizing, and thus is not expected to damage tissues and DNA, unlike X-rays. Some frequencies of terahertz radiation can penetrate several millimeters of tissue with low water content (e.g. fatty tissue) and reflect back. Terahertz radiation can also detect differences in water content and density of a tissue. Such methods could allow effective detection of epithelial cancer with a safer and less invasive or painful system using imaging.
o Some frequencies of terahertz radiation can be used for 3D imaging of teeth and may be more accurate and safer than conventional X-ray imaging in dentistry.
* Security:
o Terahertz radiation can penetrate fabrics and plastics, so it can be used in surveillance, such as security screening, to uncover concealed weapons on a person, remotely. This is of particular interest because many materials of interest have unique spectral "fingerprints" in the terahertz range. This offers the possibility to combine spectral identification with imaging. Passive detection of Terahertz signatures avoid the bodily privacy concerns of other detection by being targeted to a very specific range of materials and objects.
* Scientific use and imaging:
o Spectroscopy in terahertz radiation could provide novel information in chemistry and biochemistry.
o Recently developed methods of THz time-domain spectroscopy (THz TDS) and THz tomography have been shown to be able to perform measurements on, and obtain images of, samples which are opaque in the visible and near-infrared regions of the spectrum. The utility of THz-TDS is limited when the sample is very thin, or has a low absorbance, since it is very difficult to distinguish changes in the THz pulse caused by the sample from those caused by long term fluctuations in the driving laser source or experiment. However, THz-TDS produces radiation that is both coherent and broadband, so such images can contain far more information than a conventional image formed with a single-frequency source.
o A primary use of submillimeter waves in physics is the study of condensed matter in high magnetic fields, since at high fields (over about 15 teslas), the Larmor frequencies are in the submillimeter band. This work is performed at many high-magnetic field laboratories around the world.
o Submillimetre astronomy.
o Terahertz radiation could let art historians see murals hidden beneath coats of plaster or paint in centuries-old building, without harming the artwork.
* Communication:
o Potential uses exist in high-altitude telecommunications, above altitudes where water vapor causes signal absorption: aircraft to satellite, or satellite to satellite.
* Manufacturing:
o Many possible uses of terahertz sensing and imaging are proposed in manufacturing, quality control, and process monitoring. These generally exploit the traits of plastics and cardboard being transparent to terahertz radiation, making it possible to inspect packaged goods.

Terahertz versus submillimeter waves

The terahertz band, covering the wavelength range between 0.1 and 1 mm, is identical to the submillimeter wavelength band. However, typically, the term "terahertz" is used more often in marketing in relation to generation and detection with pulsed lasers, as in terahertz time domain spectroscopy, while the term "submillimeter" is used for generation and detection with microwave technology, such as harmonic multiplication.

Teleportation

Teleportation

Teleportation is the transfer of matter from one point to another, more or less instantaneously, either by paranormal means or through technological artifice. Teleportation has been widely utilized in works of science fiction.

Similar is apport, an earlier word used to describe what today might be called teleportation; and bilocation, in which an individual or object is said to be, or appears to be, located in two distinct places at the same instant in time. The word "teletransportation" (which simply expands Charles Fort's abbreviated term) was first employed by Derek Parfit as part of a thought exercise on identity.

The word was coined in 1931[1][2] by American writer Charles Fort to describe the strange disappearances and appearances of anomalies, which he suggested may be connected. He joined the Greek prefix tele- (meaning "distant") to the Latin verb portare (meaning "to carry"). Fort's first formal use of the word was in the second chapter of his 1931 book, Lo! "Mostly in this book I shall specialize upon indications that there exists a transportory force that I shall call Teleportation." Though, with his typical half-serious jokiness, Fort added, "I shall be accused of having assembled lies, yarns, hoaxes, and superstitions. To some degree I think so myself. To some degree, I do not. I offer the data."[3] Fort suggested that teleportation might explain various allegedly paranormal phenomena, though, typically, it's sometimes difficult to tell if Fort took his own "theory" seriously, or instead used it to point out what he saw as the inadequacy of mainstream science to account for strange phenomena.

Scenarios

One proposed means of teleportation is the transmission of data which is used to precisely reconstruct an object or organism at its destination. However, it would be impossible to travel from one point to another instantaneously; faster than light travel, as of today, is believed to be impossible. The use of this form of teleportation as a means of transport for humans still has considerable unresolved technical issues, such as recording the human body with sufficient accuracy to allow reproduction elsewhere (i.e., because of the uncertainty principle), and whether destroying a human in one place and recreating a copy elsewhere would provide a sufficient experience of continuity of existence. The reassembled human might be considered a different sentience with the same memories as the original, as could be easily proved by constructing not just one, but several copies of the original and interrogating each as to the perceived uniqueness of each. Each copy constructed using merely descriptive data, but not matter, transmitted from the origin and new matter already at the destination point would consider itself to be the true continuation of the original and yet this could not logically be true; moreover, because each copy constructed via this data-only method would be made of new matter that already existed at the destination, there would be no way, even in principle, of distinguishing the original from the copies. Many of the relevant questions are shared with the concept of mind transfer.

Dimensional teleportation is another proposed means of teleportation. Often shown in fictional works, particularly in fantasy and comic books, it involves the subject exiting one physical universe or plane of existence, then re-entering it at a different location. This method is rarely seriously considered by the scientific community, as the currently predominant theories about parallel universes assume that physical travel is not possible between them.

A third proposed means of teleportation common in science fiction (and seen in The Culture novels and The Terminator series of films) sends the subject through a wormhole or similar phenomenon, allowing transit faster than light while avoiding the problems posed by the uncertainty principle and potential signal interference. In both of the examples above, this form of teleportation is known as "Displacement" or "Topological shortcut" (Scientific American)[citation needed] which implies that this kind of teleportation may be similar in mechanism to time travel[citation needed]. Displacement teleporters would eliminate many probable objections to teleportation on religious or philosophical grounds, as they preserve the original subject intact — and thus continuity of existence.

Teleportation by means of the mind or innate personal abilities are sometimes referred to as p-Teleportation, "psychoportation", or "jaunting"; named after the fictional scientist (Jaunte) who discovered it in The Stars My Destination (originally titled Tiger! Tiger!), a science fiction novel by Alfred Bester. This method could hypothetically work through any of the mechanisms proposed above, but is usually portrayed in fiction as displacement-type or dimensional teleportation to simplify its use in the story.

Teleportation is the name given by science fiction writers to the feat of making an object or person disintegrate in one place while a perfect replica appears somewhere else. How this is accomplished is usually not explained in detail, but the general idea seems to be that the original object is scanned in such a way as to extract all the information from it, then this information is transmitted to the receiving location and used to construct the replica, not necessarily from the actual material of the original, but perhaps from atoms of the same kinds, arranged in exactly the same pattern as the original. A teleportation machine would be like a fax machine, except that it would work on 3-dimensional objects as well as documents, it would produce an exact copy rather than an approximate facsimile, and it would destroy the original in the process of scanning it. A few science fiction writers consider teleporters that preserve the original, and the plot gets complicated when the original and teleported versions of the same person meet; but the more common kind of teleporter destroys the original, functioning as a super transportation device, not as a perfect replicator of souls and bodies.

In 1993 an international group of six scientists, including IBM Fellow Charles H. Bennett, confirmed the intuitions of the majority of science fiction writers by showing that perfect teleportation is indeed possible in principle, but only if the original is destroyed. In subsequent years, other scientists have demonstrated teleportation experimentally in a variety of systems, including single photons, coherent light fields, nuclear spins, and trapped ions. Teleportation promises to be quite useful as an information processing primitive, facilitating long range quantum communication (perhaps unltimately leading to a "quantum internet"), and making it much easier to build a working quantum computer. But science fiction fans will be disappointed to learn that no one expects to be able to teleport people or other macroscopic objects in the foreseeable future, for a variety of engineering reasons, even though it would not violate any fundamental law to do so.

SyncML

SyncML

SyncML (Synchronization Markup Language) is the former name (currently referred to as: Open Mobile Alliance Data Synchronization and Device Management) for a platform-independent information synchronization standard. Existing synchronization solutions have mostly been somewhat vendor-, application- or operating system specific. The purpose of SyncML is to change this by offering an open standard as a replacement. Several major companies such as Motorola, Nokia, Sony Ericsson, LG, IBM and Siemens AG already support SyncML in their products, although LG do not support it in all their phone models, preferring to use their own proprietary syncing protocols such as LG Sync SPP. Philippe Kahn was instrumental in the founding vision for synchronization with Starfish Software, later acquired by Motorola. The founding vision as expressed by Kahn was: "Global synchronization and integration of wireless and wireline devices".

SyncML is most commonly thought of as a method to synchronize contact and calendar information (personal information manager) between some type of handheld device and a computer (personal, or network-based service), such as between a mobile phone and a personal computer. The new version of the specification includes support for push email, providing a standard protocol alternative to proprietary solutions like BlackBerry.

Some products are now using SyncML for more general information synchronization purposes, such as to synchronize project task information across a distributed group of team members. SyncML can also be used as a base for backup solutions.

Problem areas

* A fairly intricate and vague protocol specification has meant that in general there are major interworking problems with different servers against different clients.
* In addition to the server address, user name and password, SyncML requires a database name to be specified for opening a connection. This database name is not standardized, and different servers use different names for the same service. E.g. one server might use card while another ./contacts for the contact database.
* Only the over-the-air (OTA) interface has any degree of standardization (e.g. OMA CP 1.1, OTA 7.0) whereas synchronization over a local interface is not standardized, and requires specific solution for any device, if available at all.

smart card

smart card

A smart card, chip card, or integrated circuit card (ICC), is any pocket-sized card with embedded integrated circuits which can process data. This implies that it can receive input which is processed — by way of the ICC applications — and delivered as an output. There are two broad categories of ICCs. Memory cards contain only non-volatile memory storage components, and perhaps some specific security logic. Microprocessor cards contain volatile memory and microprocessor components. The card is made of plastic, generally PVC, but sometimes ABS. The card may embed a hologram to avoid counterfeiting. Using smartcards is also a form of strong security authentication for single sign-on within large companies and organizations.

A Smart Card is a plastic card the size of a credit card with an integrated circuit built into it. This integrated circuit may consist only of EEPROM in the case of a memory card, or it may also contain ROM, RAM and even a CPU.

Most smart cards have been designed with the look and feel of a credit or debit card, but can function on at least three levels (credit - debit - personal information). Smart cards include a microchip as the central processing unit, random access memory (RAM) and data storage of around 10MB.

A smart card is a mini-computer without the display screen and keyboard. Smart cards contain a microchip with an integrated circuit capable of processing and storing thousands of bytes of electronic data. Due to the portability and size of smart cards they are seen as the next generation of data exchange.

Smart cards contain an operating system just like personal computers. Smart cards can store and process information and are fully interactive. Advanced smart cards also contain a file structure with secret keys and encryption algorithms. Due to the encrypted file system, data can be stored in separated files with full security.

Organizations are steadily migrating toward this technology. The days are numbered for a single mainframe used for computing every directive. Today, the delegation of tasks is being transferred to small, but dedicated smart cards. Their usefulness may soon exceed that of the standard computer for a variety of applications due, in part, to their portability and ease of use.

The smart card is an electronic recording device. Information in the microchip can instantaneously verify the cardholder's identity and any privileges to which the cardholder may be entitled. Information such as withdrawals, sales, and bills can be processed immediately and if/when necessary; those records can be transmitted to a central computer for file updating.

Smart cards are secure, compact and intelligent data carriers. Smart cards should be regarded as specialized computers capable of processing, storing and safeguarding thousands of bytes of data. Smart cards have electrical contacts and a thin metallic plate just above center line on one side of the card. Beneath this dime-sized plate is an integrated circuit (IC) chip containing a central processing unit (CPU), random access memory (RAM) and non-volatile data storage. Data stored in the smart card's microchip can be accessed only through the chip operating system (COS), providing a high level of data security. This security takes the form of passwords allowing a user to access parts of the IC chip's memory or encryption/decryption measures which translate the bytes stored in memory into useful information.

Smart cards typically hold 2,000 to 8,000 electronic bytes of data (the equivalent of several pages of data). Because those bytes can be electronically coded, the effective storage capacity of each card is significantly increased. Magnetic-stripe cards, such as those issued by banks and credit card companies, lack the security of microchips but remain inexpensive due to their status as a single-purpose card. Smart cards can be a carrier of multiple records for multiple purposes. Once those purposes are maximized, the smart card is often viewed as superior and, ultimately, less expensive. The distributed processing possible with smart cards reduces the need for ever-larger mainframe computers and the expense of local and long-distance phone circuits required to maintain an on-line connection to a central computer.

Overview

A "smart card" is also characterized as follows:

* Dimensions are normally credit card size. The ID-1 of ISO/IEC 7810 standard defines them as 85.60 × 53.98 mm. Another popular size is ID-000 which is 25 × 15 mm (commonly used in SIM cards). Both are 0.76 mm thick.
* Contains a security system with tamper-resistant properties (e.g. a secure cryptoprocessor, secure file system, human-readable features) and is capable of providing security services (e.g. confidentiality of information in the memory).
* Asset managed by way of a central administration system which interchanges information and configuration settings with the card through the security system. The latter includes card hotlisting, updates for application data.
* Card data is transferred to the central administration system through card reading devices, such as ticket readers, ATMs etc.

[edit] Benefits

Smart cards can be used for identification, authentication, and data storage.

Smart cards provide a means of effecting business transactions in a flexible, secure, standard way with minimal human intervention.

Smart card can provide strong authentication for single sign-on or enterprise single sign-on to computers, laptops, data with encryption, enterprise resource planning platforms such as SAP, etc.

History

The automated chip card was invented by German rocket scientist Helmut Gröttrup and his colleague Jürgen Dethloff in 1968; the patent was finally approved in 1982. The first mass use of the cards was for payment in French pay phones, starting in 1983 (Télécarte).

Roland Moreno actually patented his first concept of the memory card in 1974. In 1977, Michel Ugon from Honeywell Bull invented the first microprocessor smart card. In 1978, Bull patented the SPOM (Self Programmable One-chip Microcomputer) that defines the necessary architecture to auto-program the chip. Three years later, the very first "CP8" based on this patent was produced by Motorola. At that time, Bull had 1200 patents related to smart cards. In 2001, Bull sold its CP8 Division together with all its patents to Schlumberger. Subsequently, Schlumberger combined its smart card department and CP8 and created Axalto. In 2006, Axalto and Gemplus, at the time the world's no.2 and no.1 smart card manufacturers, merged and became Gemalto.

The second use was with the integration of microchips into all French debit cards (Carte Bleue) completed in 1992. When paying in France with a Carte Bleue, one inserts the card into the merchant's terminal, then types the PIN, before the transaction is accepted. Only very limited transactions (such as paying small autoroute tolls) are accepted without PIN.

Smart-card-based electronic purse systems (in which value is stored on the card chip, not in an externally recorded account, so that machines accepting the card need no network connectivity) were tried throughout Europe from the mid-1990s, most notably in Germany (Geldkarte), Austria (Quick), Belgium (Proton), France (Moneo), the Netherlands (Chipknip and Chipper), Switzerland ("Cash"), Norway ("Mondex"), Sweden ("Cash"), Finland ("Avant"), UK ("Mondex"), Denmark ("Danmønt") and Portugal ("Porta-moedas Multibanco").

The major boom in smart card use came in the 1990s, with the introduction of the smart-card-based SIM used in GSM mobile phone equipment in Europe. With the ubiquity of mobile phones in Europe, smart cards have become very common.

The international payment brands MasterCard, Visa, and Europay agreed in 1993 to work together to develop the specifications for the use of smart cards in payment cards used as either a debit or a credit card. The first version of the EMV system was released in 1994. In 1998 a stable release of the specifications was available. EMVco, the company responsible for the long-term maintenance of the system, upgraded the specification in 2000 and most recently in 2004. The goal of EMVco is to assure the various financial institutions and retailers that the specifications retain backward compatibility with the 1998 version.

With the exception of countries such as the United States of America there has been significant progress in the deployment of EMV-compliant point of sale equipment and the issuance of debit and or credit cards adhering the EMV specifications. Typically, a country's national payment association, in coordination with MasterCard International, Visa International, American Express and JCB, develop detailed implementation plans assuring a coordinated effort by the various stakeholders involved.

The backers of EMV claim it is a paradigm shift in the way one looks at payment systems. In countries where banks do not currently offer a single card capable of supporting multiple account types, there may be merit to this statement. Though some banks in these countries are considering issuing one card that will serve as both a debit card and as a credit card, the business justification for this is still quite elusive. Within EMV a concept called Application Selection defines how the consumer selects which means of payment to employ for that purchase at the point of sale.

For the banks interested in introducing smart cards the only quantifiable benefit is the ability to forecast a significant reduction in fraud, in particular counterfeit, lost and stolen. The current level of fraud a country is experiencing, coupled with whether that country's laws assign the risk of fraud to the consumer or the bank, determines if there is a business case for the financial institutions. Some critics claim that the savings are far less than the cost of implementing EMV, and thus many believe that the USA payments industry will opt to wait out the current EMV life cycle in order to implement new, contactless technology.

Smart cards with contactless interfaces are becoming increasingly popular for payment and ticketing applications such as mass transit. Visa and MasterCard have agreed to an easy-to-implement version currently being deployed (2004-2006) in the USA. Across the globe, contactless fare collection systems are being implemented to drive efficiencies in public transit. The various standards emerging are local in focus and are not compatible, though the MIFARE Standard card from Philips has a considerable market share in the US and Europe.

Smart cards are also being introduced in personal identification and entitlement schemes at regional, national, and international levels. Citizen cards, drivers’ licenses, and patient card schemes are becoming more prevalent; For example in Malaysia, the compulsory national ID scheme MyKad includes 8 different applications and is rolled out for 18 million users. Contactless smart cards are being integrated into ICAO biometric passports to enhance security for international travel.

Contact smart card

Contact smart cards have a contact area, comprising several gold-plated contact pads, that is about 1 cm square. When inserted into a reader, the chip makes contact with electrical connectors that can read information from the chip and write information back.
The ISO/IEC 7816 and ISO/IEC 7810 series of standards define:

* the physical shape
* the positions and shapes of the electrical connectors
* the electrical characteristics
* the communications protocols, that includes the format of the commands sent to the card and the responses returned by the card.
* robustness of the card
* the functionality

The cards do not contain batteries; energy is supplied by the card reader.

Smart Card Usage

The uses of smart cards are as versatile as any mini-computer. At a hospital emergency room, for example, the card could identify the person's health-insurance carrier and transfer all necessary information from the microchip to an admittance sheet. Tests, treatment, billing and prescriptions could be processed more quickly using the card. Major clinical findings could be added to the medical information section within the microchip.

In the U.S., smart cards are utilized in GSM mobile telephones, in DirecTV and EchoStar satellite receivers, and in the American Express Blue card.

Smart Card Operating Systems

Smart cards designed for specific applications may run proprietary operating systems. Smart cards designed with the capability to run multiple applications usually run MULTOS or Java Card.

ZigBee

ZigBee

ZigBee is a specification for a suite of high level communication protocols using small, low-power digital radios based on the IEEE 802.15.4-2003 standard for wireless personal area networks (WPANs), such as wireless headphones connecting with cell phones via short-range radio. The technology defined by the ZigBee specification is intended to be simpler and less expensive than other WPANs, such as Bluetooth. ZigBee is targeted at radio-frequency (RF) applications that require a low data rate, long battery life, and secure networking.

The ZigBee Alliance is a group of companies which maintain and publish the ZigBee standard.

Overview

ZigBee is a low-cost, low-power, wireless mesh networking proprietary standard. The low cost allows the technology to be widely deployed in wireless control and monitoring applications, the low power-usage allows longer life with smaller batteries, and the mesh networking provides high reliability and larger range.

The ZigBee Alliance, the standards body which defines ZigBee, also publishes application profiles that allow multiple OEM vendors to create interoperable products. The current list of application profiles either published or in the works are:

* Home Automation
* ZigBee Smart Energy
* Commercial Building Automation
* Telecommunication Applications
* Personal, Home, and Hospital Care

The relationship between IEEE 802.15.4 and ZigBee is similar to that between IEEE 802.11 and the Wi-Fi Alliance. The ZigBee 1.0 specification was ratified on 14 December 2004 and is available to members of the ZigBee Alliance. Most recently, the ZigBee 2007 specification was posted on 30 October 2007. The first ZigBee Application Profile, Home Automation, was announced 2 November 2007.

For non-commercial purposes, the ZigBee specification is available free to the general public. An entry level membership in the ZigBee Alliance, called Adopter, costs US$3500 annually and provides access to the as-yet unpublished specifications and permission to create products for market using the specifications.

ZigBee operates in the industrial, scientific and medical (ISM) radio bands; 868 MHz in Europe, 915 MHz in the USA and Australia, and 2.4 GHz in most jurisdictions worldwide. The technology is intended to be simpler and less expensive than other WPANs such as Bluetooth. ZigBee chip vendors typically sell integrated radios and microcontrollers with between 60K and 128K flash memory, such as the Freescale MC13213, the Ember EM250 and the Texas Instruments CC2430. Radios are also available stand-alone to be used with any processor or microcontroller. Generally, the chip vendors also offer the ZigBee software stack, although independent ones are also available.

"In the U.S., as of 2006, the retail price of a Zigbee-compliant transceiver is approaching $1, and the price for one radio, processor, and memory package is about $3." Comparatively, the price of consumer-grade Bluetooth chips is now under $3.. In other countries the prices are higher. For example in the UK, (March 2009) the one-off cost to a hobbyist for a barebones ZigBee surface-mount transceiver IC varies from £5 to £9, with pre-assembled modules around £10 more (excluding aerials).

Because Zigbee can activate (go from sleep to active mode) in 15 msec or less, the latency can be very low and devices can be very responsive — particularly compared to Bluetooth wake-up delays, which are typically around three seconds. Because Zigbees can sleep most of the time, average power consumption can be very low, resulting in long battery life.

The first stack release is now called Zigbee 2004. The second stack release is called Zigbee 2006, and mainly replaces the MSG/KVP structure used in 2004 with a "cluster library". The 2004 stack is now more or less obsolete.

Zigbee 2007, now the current stack release, contains two stack profiles, stack profile 1 (simply called ZigBee), for home and light commercial use, and stack profile 2 (called ZigBee Pro). ZigBee Pro offers more features, such as multi-casting, many-to-one routing and high security with Symmetric-Key Key Exchange (SKKE), while ZigBee (stack profile 1) offers a smaller footprint in RAM and flash. Both offer full mesh networking and work with all ZigBee application profiles.

ZigBee 2007 is fully backward compatible with ZigBee 2006 devices: A ZigBee 2007 device may join and operate on a ZigBee 2006 network and vice versa. Due to differences in routing options, ZigBee Pro devices must become non-routing ZigBee End-Devices (ZEDs) on a ZigBee 2006 or ZigBee 2007 network, the same as ZigBee 2006 or ZigBee 2007 devices must become ZEDs on a ZigBee Pro network. The applications running on those devices work the same, regardless of the stack profile beneath them.

Uses

ZigBee protocols are intended for use in embedded applications requiring low data rates and low power consumption. ZigBee's current focus is to define a general-purpose, inexpensive, self-organizing mesh network that can be used for industrial control, embedded sensing, medical data collection, smoke and intruder warning, building automation, home automation, etc. The resulting network will use very small amounts of power — individual devices must have a battery life of at least two years to pass ZigBee certification[8].

Typical application areas include

* Home Entertainment and Control — Smart lighting, advanced temperature control, safety and security, movies and music

* Home Awareness — Water sensors, power sensors, smoke and fire detectors, smart appliances and access sensors

* Mobile Services — m-payment, m-monitoring and control, m-security and access control, m-healthcare and tele-assist

* Commercial Building — Energy monitoring, HVAC, lighting, access control

* Industrial Plant — Process control, asset management, environmental management, energy management, industrial device control

Device types

There are three different types of ZigBee devices:

* ZigBee coordinator (ZC): The most capable device, the coordinator forms the root of the network tree and might bridge to other networks. There is exactly one ZigBee coordinator in each network since it is the device that started the network originally. It is able to store information about the network, including acting as the Trust Centre & repository for security keys.
* ZigBee Router (ZR): As well as running an application function, a router can act as an intermediate router, passing on data from other devices.
* ZigBee End Device (ZED): Contains just enough functionality to talk to the parent node (either the coordinator or a router); it cannot relay data from other devices. This relationship allows the node to be asleep a significant amount of the time thereby giving long battery life. A ZED requires the least amount of memory, and therefore can be less expensive to manufacture than a ZR or ZC.

Software and hardware

The software is designed to be easy to develop on small, inexpensive microprocessors. The radio design used by ZigBee has been carefully optimized for low cost in large scale production. It has few analog stages and uses digital circuits wherever possible.

Even though the radios themselves are inexpensive, the ZigBee Qualification Process involves a full validation of the requirements of the physical layer. This amount of concern about the Physical Layer has multiple benefits, since all radios derived from that semiconductor mask set would enjoy the same RF characteristics. On the other hand, an uncertified physical layer that malfunctions could cripple the battery lifespan of other devices on a ZigBee network. Where other protocols can mask poor sensitivity or other esoteric problems in a fade compensation response, ZigBee radios have very tight engineering constraints: they are both power and bandwidth constrained. Thus, radios are tested to the ISO 17025 standard with guidance given by Clause 6 of the 802.15.4-2006 Standard. Most vendors plan to integrate the radio and microcontroller onto a single chip.

ZigBee and ZigBee PRO technologies
All ZigBee technology devices implement a layered stack architecture. The ZigBee stack uses the IEEE 802.15.4 Physical (PHY) and Medium Access Control (MAC) Layers. In addition to the IEEE layers, the ZigBee Alliance has defined a set of standardized layers that sit on top of the IEEE layers and together these layers make up the ZigBee technology stack architecture.

The lower layers (including PHY/MAC, Network and Security layers) make up the ZigBee stack. On top of this there is an Application layer which will be specific to the particular "Profile" being implemented. The Profile contains the protocol that is specific to the application ZigBee is being used to implement.

Two types of ZigBee technology have been defined. These are ZigBee and ZigBee PRO. The differences between the types relate to network architecture and available security, however they have been design to allow a mixture of types within one network under certain network configurations. For further information relating to the two types of ZigBee technology click on the following link ZigBee & ZigBee PRO
Global Approvals

In addition to the regulatory Radio, Safety and EMC requirements that apply to ZigBee devices, the ZigBee Alliance has put in place a certification process that must be satisfied prior to using the ZigBee name or logo.

For further information on gaining market access to specific markets, just follow the relevant link:

* European
* North America
* South and Central America
* Africa
* Asia
* Australasia
* Middle East

The ZigBee Advantage

The ZigBee protocol was designed to carry data through the hostile RF environments that routinely exist in commercial and industrial applications.

ZigBee protocol features:

* Low duty cycle - Provides long battery life
* Low latency
* Support for multiple network topologies: Static, dynamic, star and mesh
* Direct Sequence Spread Spectrum (DSSS)
* Up to 65,000 nodes on a network
* 128-bit AES encryption – Provides secure connections between devices
* Collision avoidance
* Link quality indication
* Clear channel assessment
* Retries and acknowledgements
* Support for guaranteed time slots and packet freshness

White lead

White lead

White lead is the chemical compound (PbCO3)2·Pb(OH)2. It was formerly used as an ingredient for lead paint and a cosmetic called Venetian Ceruse, because its opaque quality made it a good pigment. However, it tended to cause lead poisoning, and its use has been banned in most countries.

White lead has been the principal white of classical European oil painting. There have been claims that it is partly responsible for darkening of old paintings over time, reacting with trace amounts of hydrogen sulfide in the air to produce black lead sulfide. Other authorities dispute this; the most traditional view is that impermanent pigments and dirty varnish (which is often cleanable) are more likely responsible for darkening. In any event, white lead has been mostly supplanted in artistic use by titanium white, which is structurally weaker than white lead. White lead is less used by today's painters, not because of its toxicity directly; but simply because its toxicity in other contexts has led to trade restrictions that make lead white difficult for artists to obtain in sufficient quantities.

Historically, white lead was produced by the Dutch process. This involved casting metallic lead as thin buckles. These were corroded with acid in the presence of carbon dioxide. Next they were placed in pots with a little vinegar (containing acetic acid). These were stacked up and left for six to fourteen weeks, by which time the blue-grey lead had corroded to white lead. The pots were then taken to a separating table where scraping and pounding removed the white lead from the buckles. The powder was then dried and packed for shipment.

In the eighteenth century, white lead paints were routinely used to repaint the hulls and floors of Royal Navy vessels, to waterpoof the timbers and limit infestation by teredo navalis worms.

White lead occurs naturally as a mineral, in which context it is known as hydrocerussite

corDECT

corDECT



corDECT is a wireless local loop standard developed in India by IIT Madras and Midas Communications (www.midascomm.com) at Chennai, under leadership of Prof Ashok Jhunjhunwala, based on the DECT digital cordless phone standard.

Overview

The technology is a Fixed Wireless Option, which has extremely low capital costs and is ideal for small start ups to scale, as well as for sparse rural areas. It is very suitable for ICT4D projects and India has one such organization, n-Logue Communications that has aptly done this.

The full form of DECT is Digital Enhanced Cordless Telecommunications, which is useful in designing small capacity WLL (wireless in local loop) systems. These systems are operative only on LOS Conditions and are very much affected by weather conditions.

System is designed for rural and sub urban areas where subscriber density is medium or low. "corDECT" system provides simultaneous voice and Internet access. Following are the main parts of the system.

DECT Interface Unit (DIU)
This is a 1000 line exchange provides E1 interface to the PSTN. This can cater up to 20 base stations. These base stations are interfaced through ISDN link which carries signals and power feed for the base stations even up to 3 km.

Compact Base Station (CBS)
This is the radio fixed part of the DECT wireless local loop. CBSs are typically mounted on a tower top which can cater up to 50 subscribers with 0.1 erlang traffic.

Base Station Distributor (BSD)
This is a traffic aggregator used to extend the range of the wireless local-loop where 4 CBS can be connected to this.

Relay Base Station (RBS)

This another technique used to extend the range of the corDECT wireless local loop up to 25 km by a radio chain.


Fixed Remote Station (FRS)
This is the subscriber-end equipment used the corDECT wireless local loop which provides standard telephone instrument and Internet access up to 70kbit/s through Ethernet port.

The new generation corDECT technology is called Broadband corDECT which supports provides broadband Internet access over wireless local loop.