|SCIENCE & TECHNOLOGY|
An embedded system is a special-purpose computer system built into a smaller device. Some of the application areas, where embedded systems, are finding use are, washing machines, microwave ovens, toys, electronic ignition systems, television, cameras, digital clock, mobile phones, dishwashers, dryers, ATMs, Calculators, printers, medical equipment, measuring instruments, flight control systems, PDAs, PLCs and so on.
The basic module of an embedded system is a microprocessor or a microcontroller. A microcontroller is a special-purpose computer incorporating "system on chip". The processor, ROM, RAM and I/O is present on the single chip named "microcontroller". They are dedicated to one special task and are generally low-power devices.
Microcontrollers are "embedded" inside some other device, and thereby derive the name, "embedded controller". Embedded systems generally use a slow processor, and a small memory size to minimise cost. The peripherals are controlled by synchronous serial interfaces.
Programmes on embedded systems, usually run with meagre hardware resources and some limitations in real-time operations. There are varieties of CPU architectures, which enable embedded design. The designers of embedded systems make use of compilers, assemblers and debuggers for development purpose.
A general-purpose embedded operating system does not exist. The embedded system designer, ports one, application specific "real time operating system" onto the new system. All embedded systems need a start-up-code. It tests the internal CPU, ROM, RAM, and software and then initiates the application code. In an embedded system, the instruction-based microcontroller works with both the hardware and the software components. Embedded software is the software, etched onto the chip. An embedded system is a collection of such chips to give a particular application.
A typical "System on Chip" device incorporates a digital signal processor (DSP), micro-controller/microprocessor, analogue circuitry, memory and other components.
Embedded software is immune to viruses, and thus it helps in designing robust and critical applications. Embedding the software onto the hardware has paved the way for embedded system intelligence. The embedded system design is emerging as a "sunshine" area, in the Indian IT boom. This is a potential export market. In India, companies like STMicroelectronics, Texas Instruments, Intel, Cadence, Mentor Graphics, Synopsys, and Wipro have taken a leap into this emerging area of embedded system design and development. Thus, we conclude that, platform independent software design gave way to embedded software design. This, in turn, has paved the way for embedded system design, which is more of an evolution, rather than revolution. The day is not far when each living being, and non-living application will incorporate an embedded system.
The writer is Asst. Professor, Dept. of Electronics Punjab Engg. College Chandigarh.
Power from bamboos
Indian scientists have successfully developed two unique power projects by using bamboo to generate electricity. The plants with a capacity of 1 MW each would be commissioned in Assam by February next year.
"This would be the first of its kind where we are using bamboo and its wastes to generate electricity," said Vinay S. Oberoi, director of the National Mission on Bamboo Applications (NMBA). "This would not only be cost effective but also highly eco-friendly," Oberoi told IANS.
The NMBA is an agency set up by the central government to promote value addition and commercialisation of the country’s 80 million tonnes of bamboo crop annually. The two projects, set up at an estimated cost of Rs.100 million, were designed and developed by scientists at the Indian Institute of Science, Bangalore.
The technology has been developed, tested and stabilised and is now available for large scale induction, suitable for application in the 10 KW-1 MW range. Experts from the Bangalore-based institute in collaboration with the NMBA are also working to develop a 100 KW power plant for the Indian army.
India is the second highest bamboo producing country after China. More than 55 percent of India’s annual bamboo crops are grown in the northeastern region. There were reports of bamboo flowering in the states of Assam, Arunachal Pradesh, Mizoram, Manipur and Tripura.
According to legend, when bamboo flowers, famine, death and destruction follow.
"We are trying to harvest flowering bamboos in a big way from Mizoram and other northeastern states so that we could use it for other purposes like making low-cost pre-fabricated homes," said Jayanta Madhab, NMBA’s economic advisor.
"Not only would the scare of famine vanish if we harvest the bamboos but it would also help boost the rural economy to a great extent." The government in the earthquake-devastated state of Jammu and Kashmir was lifting bamboo shelters in large numbers for rehabilitating victims.
"We gave the idea to the Jammu and Kashmir government and now they are placing orders to at least four manufacturers of bamboo shelters in Assam, Arunachal Pradesh and West Bengal," Oberoi said.
"It requires just three hours assembling a 120 to 140 sq ft bamboo shelter. — IANS
With hybrid cars making waves in the auto industry, hybrid solar lighting might be the next big splash — combining the benefits of sunlight with the consistency of traditional electric lighting.
Hybrid solar lighting (HSL) is different than traditional solar power, which converts sunlight into electricity. HSL captures sunlight and channels it directly into a room, using optical fibers.
"Our idea was: let’s just pipe the sunlight into the building," said Duncan Earl, a researcher at Oak Ridge National Laboratory.
During times of little or no sunlight, HSL light fixtures use electricity to provide a constant amount of illumination.
If used in a top floor of a building, HSL can deliver 50 per cent of collected sunlight as indoor lighting, Earl told LiveScience in a telephone interview.
Tea cuts ovary cancer risk
Need any more excuses to drink tea? A new study says women who drink at least two cups of tea a day have a lower risk of developing ovarian cancer than those who do not drink tea at all.
Evidence from laboratory studies has always indicated that green and black tea preparations may protect against various cancers. But few epidemiological studies have examined the relationship between tea consumption and risk of ovarian cancer.
Susanna C Larsson and Alicja Wolk of National Institute of Environmental Medicine in Stockholm, prospectively examined this relationship in 61,057 women, aged 40 to 76, who were participants in a population-based Swedish study.
The volunteers completed a validated 67-item food frequency questionnaire at enrollment between 1987 and 1990, and were followed for cancer incidence through December 2004.
Sixty-eight per cent of the participants reported drinking tea (mainly black tea) at least once per month. During an average follow-up of 15.1 years, 301 women were diagnosed as having invasive epithelial ovarian cancer. — PTI
Oral vaccine for hepatitis B
In a significant development, scientists have developed oral form of hepatitis B vaccine and insulin, thus doing away with the high cost and pain of injections, and claimed the two were as effective as their injectible counterparts in animal studies.
"Preclinical studies have taken place in
rats and mice. In both the cases, the proteins are the same as their injectible
counterparts. Our research involved only delivery mechanisms," Dr
Koteshwar Rao, chairman, of Transgene Biotek, which along with Indian Institute
of Chemical Technology, Hyderabad, has developed the two oral forms of
hepatitis-B vaccine and insulin. — PTI
Why stereo-sound gives more pleasant effect than a mono-sound? Why the right and the left speakers are essential to get a stereo effect?
Let me start with the second part of your question. You could as well have asked, "Why two ears, one on the right and the other on the left side of our head are essential for us and most other animals"! It seems to me that we are designed to primarily sense the world when standing or sitting. In these positions the world that is accessible to sound sensing is spread in a near horizontal plane. The fact that a distance - the thickness of our head - separates the two ears with equal sensitivity enables us to determined the direction of the sound. The reason for this capability is that our brain can tell the difference in times at which the sound arrives at the two ears. (Notice how this capability is connected with the velocity sound in air)!
A sound made anywhere except at points on a plane half way between and normal to the line joining our ears would take different times reaching the two ears. That is what enables us to tell the direction from which the sound is coming. (I find it amazing that all living things, even babies, can do these complex trigonometric calculations without knowing any trigonometry). Often the source of musical sounds is spatially extended. There might be a vocalist sitting some distance from a tabla player.
Or there might be a large orchestra on stage with several musicians handling different instruments. If the sound from the two sides of the stage were picked up by separate microphones and through separate channels transported after amplification to two different speakers appropriately placed, the music would come alive. The spread of the orchestra would be better appreciated, including the components added by different performers. A single microphone and a single speaker cannot match the impact of a stereo performance. In essence one can also say that a stereo recording can give all of us a seat close to the stage. It is of course for us to decide how close is the most enjoyable close. That can be built into the recording.
What is post-mortem?
If a person dies and we do not know why
he died, it is often possible to examine carefully his internal organs
of the dead body to ascertain the cause of death. Such requirements
become necessary in cases of suspected crime, accident, even
malpractice. Sometimes you may also need to do a postmortem if the death
happens when it was not expected, to clinically understand what really