Wednesday, May 9, 2007

What's new with Oracle Database

Sign up for the FREE, Oracle Database Insider newsletter; Press release: Oracle Introduces Oracle Information Lifecycle Management Assistant; Gartner Report: Findings from Oracle OpenWorld 2006: Users Are Investing in Oracle's DBMS Infrastructure

Oracle Database: Oracle Database 10g delivers record-breaking performance and scalability on Windows, Linux, and UNIX servers and provides fast ROI by moving from a single server to Grid Computing without changing a single line of code.; Oracle Database 10g delivers better results by automating administrative tasks, providing industry-leading security and regulatory compliance features, and enabling the highest availability with Real Application Clusters (RAC).

Leading Analyst: "RAC Should be a Part of Your Oracle DBMS Strategy": Over the past year, Forrester Research interviewed 35 Oracle customers using Oracle Real Application Clusters (RAC). In their subsequent report, "Oracle RAC Gains Momentum," September 2005, Forrester describes how most customers affirmed that RAC meets or exceeds their high-availability requirements to support mission-critical database applications.; Forrester notes that Oracle RAC delivers the most innovative and superior solution in the industry. It supports all kinds of applications, such as data warehouses, OLTP, or mixed environments.

digital photo editor with simple, user friendly interface

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We are no 'Frankenstein'

By Munir Kotadia, and Scott Mckenzie, ZDNet Australia

The Mozilla Foundation is no "Frankenstein," haphazardly thrown together in open-source development, CEO Mitchell Baker said this week.

Baker, speaking at CeBit Australia 2007 in Sydney, also challenged the perception that open-source vendors are just ad hoc organizations and took the chance to bang the security message home, claiming that Microsoft's Internet Explorer was vulnerable to attack for 285 days last year, compared with just 9 days for Firefox.

In a separate interview with ZDNet Australia, Baker took a swipe at Microsoft and the software giant's definition of collaboration.

"I don't think you should let a word or concept as important as 'collaboration' be defined by Microsoft to mean calendar and e-mail integration. Collaboration, especially for millions of people on the Web is about many other things," she said.

Baker said she believes that the creation of the Mozilla Foundation and the Firefox Web browser are living examples of what collaboration can produce.

While she wasn't dismissive of e-mail and calendar integration, Baker said the level of collaboration that Mozilla and other open-source projects demonstrate dwarf the interaction between those two pieces of software.

The Mozilla CEO also acknowledged that competition is heating up in the browser space. According to Baker, Microsoft is taking notice of Firefox and "is back investing in the browser".

"It is very clear that IE will have a least one nice feature that we don't. That I think we should take as a given," she said. "Most people like Firefox and they trust Firefox, and that is because of the way we build it. We don't have anything to hide behind. We can't hide behind our mistakes because they are all out there in the public," she added.

Munir Kotadia and Scott Mckenzie of ZDNet Australia reported from Sydney.

Ultra-cheap cell phones

By Stephen Shankland, CNET News.com

Sun Microsystems' answer to One Laptop Per Child.

The server and software company hopes to sell a version of Java to phone companies that will bring network access to the world's computers, executives said here at the JavaOne trade show.

"Java will play a central role in bringing the Internet to the planet," Chief Executive Jonathan Schwartz said during a news conference. "It will be the software to build the devices to bridge the digital divide." In a brief speech at the show, Schwartz indicated he believed the Java-powered mobile phones could be sold for $30 to $50 apiece.

That's a notch cheaper than the $100 price the One Laptop Per Child (OLPC) initiative hopes to reach in 2008. OLPC began at the MIT Media Lab but now is a separate initiative to build easy-to-use, Linux-powered wirelessly networked devices.

Sun isn't building its own phone, Schwartz said. Instead, the company expects partnerships with manufacturers that will have the direct relationships with customers. "We're not there to disintermediate them from their audience," Schwartz said.

Key to the vision is Java FX Mobile, based largely on technology Sun acquired when it purchased a small company called SavaJe in April. Sun has worked for years to develop Java as a technology that it licenses to others, but the Java FX Mobile software is a product that the company will sell.

Java FX Mobile is geared for small devices, but its Java interface is most similar to the Java Standard Edition (SE) software that runs on standard PCs, said James Gosling, often called the father of Java. However, the software also can run the host of Java applications that have been written for the prevailing incarnation of Java for mobile phones, called Mobile Internet Device Platform (MIDP). MIDP is based on the more compact Java Micro Edition (ME).

Java FX Mobile will usher in a new, more direct phase of Sun's years-long attempt to profit from the millions of dollars it has invested in Java software since its public debut in 1995. Sun has arguably benefited indirectly from Java--for example, by holding Microsoft at bay in some domains, by keeping programmers interested in Sun, and by gaining an entree at customers that need to buy servers--but it's been companies such as IBM, Oracle and BEA Systems that have made the most money selling companies Java products to run software on servers.

Today, Sun licenses Java to mobile phone companies such as Motorola or Nokia, which get access to working "reference implementation" software and typically assemble their own collections of Java components.

But Sun expects to directly charge for Java FX Mobile. It's realistic to expect phone makers to begin using it in the first half of 2008, said Rich Green, Sun's executive vice president of software.

Sun will ship phone manufacturers a pre-built "binary" that sidesteps some of the issues of compatibility that have dogged Java in mobile phones. Sun long has billed Java's advantage as "write once, run anywhere," but because phone makers enabled different modules of Java, software written for one phone might not run on another.

"Java FX is a binary product. You can't have fragmentation if it's a binary implementation," Green said. "That business model saves time and energy on the part of licensees who don't have to spend time mucking with source code."

Sun showed Java FX Mobile applications, including Yahoo Go mobile Internet services, running on a mobile phone. The phone, a model from First International Computer, ran the Java FX Mobile software on a stripped-down version of Linux, Gosling said.

Sun has been trying to bring today's unconnected billions onto the Internet for years, in part because it hopes to sell back-end equipment to the banks, governments and others who will provide Internet-based services.

To further this effort, Schwartz described an initiative he termed "engineers without borders" to try to marshal the energy of technologists to improve the lot of humanity.

"There's a lot of passion about people trying to bring technology to the developing world," Schwartz said.

1.8 Million Species in Internet Encyclopedia list

from : Reuters

From apples to zebras, all 1.8 million known plant and animal species will be listed in an Internet-based "Encyclopedia of Life" under a $100 million project, scientists said on Tuesday.

The 10-year scheme, launched with initial grants of $12.5 million from two U.S.-based foundations, could aid everyone from children with biology homework to governments planning how to protect endangered species.

"The Encyclopedia of Life plans to create an entry for every named species," James Edwards, executive director of the project which is backed by many leading research institutions, told Reuters. "At the moment that's 1.8 million."

The free Encyclopedia would focus mainly on animals, plants and fungi with microbes to follow, blending text, photographs, maps and videos in a common format for each. Expansion of the Internet in recent years made the multi-media project possible.

Demonstration pages at http://www.eol.org include entries about polar bears, rice, death cap mushrooms and a "yeti crab" with hairy claws recently found in the South Pacific.

"This is about giving access to information to everyone," Jesse Ausubel, chairman of the project who works at the Rockefeller University in New York City, told Reuters.

The Encyclopedia would draw on existing databases such as for mammals, fishes, birds, amphibians and plants. English would be used at the start with translations to other languages.

Edwards said the project would give an overview of life on earth via what he termed a "macroscope" -- the opposite of a microscope through which scientists usually peer.

Species would be added as they were identified. Edwards said there might be 8-10 million on earth, adding that estimates ranged from 5-100 million. Fossil species may also be added.

The encyclopedia, to be run by a team of about 25-35 people, could help chart threats to species from pollution, habitat destruction and global warming.

The project would be led by the U.S. Field Museum, Harvard University, Marine Biological Laboratory, Missouri Botanical Garden, Smithsonian Institution, and Biodiversity Heritage Library -- a group that includes London's Natural History Museum, the New York Botanical Garden, and the Royal Botanic Garden in Kew, England.

Initial funding comes from a $10 million grant from the John D. and Catherine T. MacArthur Foundation and $2.5 million from the Alfred P. Sloan Foundation.

Extra funds would be raised in coming years.

Ausubel noted that 2007 was the 300th anniversary of the birth of Sweden's Carl Linnaeus, influential in working out ways to classify species. "If he were alive today we think he'd be jumping up and down celebrating," he said.

Children in the United States watch about four hours of television every day

Despite warnings, most U.S. babies watch TV

By Julie Steenhuysen

CHICAGO (Reuters) - About 90 percent of U.S. children under age 2 and as many as 40 percent of infants under three months are regular watchers of television, DVDs and videos, researchers

They said the number of young kids watching TV is much greater than expected.

"We don't know from the study whether it is good or bad. What we know is that it is big," said Frederick Zimmerman of the University of Washington, whose research appears in the Archives of Pediatrics and Adolescent Medicine.

A second study suggested excessive TV viewing can lead to attention and learning problems down the road.

The American Academy of Pediatrics estimates that children in the United States watch about four hours of television every day. They recommend that children under age 2 should not watch any and older children should watch no more than 2 hours a day of quality programming.

But 29 percent of parents surveyed by Zimmerman and colleagues believe baby-oriented TV and DVD programs offer educational benefits.

"Parents are getting the message loud and clear from marketers of TV and videos that this is good for their kids. That it will help their brain development ... None of this stuff has ever been proven," Zimmerman said in a telephone interview.

For their study, Zimmerman's team conducted random telephone surveys of more than 1,000 families with young children in Minnesota and Washington.

They found 90 percent of children under age 2 and 40 percent of infants under three months watched TV regularly.

At 3 months, children watched less than an hour per day, but by 24 months, they watched more than 1.5 hours per day.

About half of the shows watched were in the educational category, with the remainder split evenly among noneducational children's content, baby DVDs/videos and adult TV.

TV IN THE BEDROOM

In a separate survey of 1,051 parents published in the journal Pediatrics, 75 percent of children aged 0 to 6 were found to watch TV every day, often in their own bedrooms.

"We don't know that it is bad but we don't know that it is harmless," Zimmerman said.

A second study in the Archives of Pediatrics & Adolescent Medicine found that teens who watch three to four hours of television a day are more likely to have attention or learning problems and are less likely to get a college degree.

"Even watching more than an hour of TV per day had some adverse consequences, but three hours was much worse than one hour, and two was worse than one," Jeffrey Johnson of Columbia University College of Physicians and Surgeons and the New York State Psychiatric Institute said in a telephone interview.

Johnson and colleagues studied 678 families in New York state over more than 20 years.

"Kids who watched less than one hour of TV per day were twice as likely to go to college as those who watched three or more hours per day," he said.

Just 12 percent of the parents whose children watched less than an hour of television a day said their child "hardly ever does homework," compared to 21 percent of those who watched one to three hours a day and 27 percent of those who watched more than three hours a day.

Parents said 22 percent of teens who watched less than an hour a day were often bored at school, compared to 35 percent of the moderate watchers and 42 percent of those who watched three hours or more.

The result was the same regardless of socioeconomic status.

Johnson said he believes TV may be shortening teens' attention spans. "Over time, it could really dumb down society," he said.

Java at Mobile Phone

By Henry Kingman

Sun will ship a "pre-integrated," GPL-licensable, Linux- and Java-based operating system software reference design for mobile phone...more

Roxio Crunches Video for Apple TV, iPod, iPhone

by : Peter Cohen, Macworld

Roxio on Tuesday introduced Crunch, a new US$39.99 application designed especially for users of the Apple TV, video iPod or the forthcoming iPhone who... more

Sunday, May 6, 2007

Design of Decission Supporting System for Agroindustry Development Base on Superior Commodity in Gorontalo)

Design of Decission Supporting System for Agroindustry Development Base on Superior Commodity in Gorontalo¹)

By : Zainudin AK. Antuli², Machfud³, Muhammad Romli³

ABSTRACT

The aim of this research is to find the system formulation of agroindustry development based superior commodity. There are seven phase, there were : analysis strategic of agroindustry using ISM and AHP method, analysis of superior commodity using AHP method, analysis of prospective agroindustry product with AHP method, analysis of potential location in developing superior commodity with MPE method, determining of optimum agreement price with Fibonacci method, financial analysis with NPV, IRR, NBCR and PP.

The models were integrated in Model Based Management System (MBMS) and the data were integrated in Data Based Management System (DBMS). The MBMS and DBMS are integrated with Dialog Management System and then all components are integrated and implemented into a computer softwere name SPABKU program.

The result of the verification showed that strategy of agroindustry` development based superior commodity was priotrizing in creating business atmosphere which supporting the growth of new agroindustry that focusing in providing facility, superior commodity was corn, agroindustry product was animal feed, potential location in development agroindustry was Gorontalo Regency, financial analysis of animal feed agroindustry is suitable and optimum agreement price Rp 1.484,01

Keywords : agroindustry, superior commodity, agroindustrial product, development strategy.

¹A Part of Master Degree Thesis in Master Degree School of Technology Agroindustry of IPB-Indonesia
² A Master Degree Student of IPB's Technology Agroindustry Program - Indonesia
³Lecturers in IPB's Technology Agroindustry Program - Indonesia

Download Link
Filename: ZAINUDIN A.K. ANTULI (F351040011).pdf
Size: 1 MB
You can download the file here: Download the file

How-to: Not get viruses and not slow your PC to a crawl

by : Liz in
In a popular article “How-to: Get viruses and slow your PC to a crawl,” Jeff explained exactly what to do in order to catch viruses and otherwise debilitate your machine. We recognize that there are some of you out there who just won’t listen. Maybe your desire for those little animated icons is too great or you’ve got to have the latest Nickelback song but you just can’t bring yourself to pay for it (we don’t blame you for the latter).

Here, Liz suggests a few ways to have your cake and eat it too. For the record, we don’t recommend putting your computer at risk. As Jeff’s article shows, one wrong click could land your computer in some pretty dire straits.

1. Go to porn websites

Everyone has their dirty little secret, but only the most learned of us know how to do this safely. Most porn on the internet IS corrupted, evil, and just an excuse to steal your information or blackmail you. Any site that asks for verification that you are 18 in any way other than an “agree” link (this must be HTML, not a button) is trying to trick you. Any website that asks you to download anything is trying to trick you. Most good popup blockers (like Google toolbar or Stopzilla) can stop the popups, leaving you free to surf one-handed. And never try to save pictures or movies to the desktop; just bookmark it secretly and come back later.

2.Try to go to Warez or Crack websites.

Any crack or warez website that has a .com address is probably bogus. The real ones use .ws, which is unregulated and is hosted in all of those loverly places that support filesharing or whatever you may have. If you want the software and you’re not going to pay for it, first off admit to yourself that that is illegal, you’re a naughty person, and you could be asking for a free stay at your local penitentiary. If you’re ok with that, note that stealing software is bad, but what’s worse is trying to make money off of it. On a side note, if you want cheap software, go OPEN SOURCE.

3. Use music sharing software.

If you want to share your music with other people, and perhaps peruse their collections at will, do it the right way. Use Bearshare, or if you must use Limewire, use it while thinking critically. Check filename extensions. Only download .mp3s; the other extensions can hide code and bring scripts along with them (and it goes without saying, don’t download executables (.exe)). Also, don’t download obvious search hooks. “Dr. Dre feat Incubus feat Shari Lewis” is obviously fake, not just a twisted perversion of all that is right and good. Only download the songs with the most copies, but avoid the ones that are directly at the top of the list. Also, the sponsored downloads are sponsored by the RIAA and usually contain trackers. Share nice now.

4. Download “free” screensavers, toolbars, browser helpers, unknown “cleaners” and that type of thing - especially software offered from pop-up ads.

While perspectives differ on what toolbars etc, are malicious or spyware (consider the debate over the popular Alexa toolbar) the key here is make to sure it’s a recognizable company. Screensavers offered from reputable companies are fine, as are toolbars and browser helpers. Even pop-up ads are fine as long as you recognize the brand. To get a sense of how reputable a program is, Google the company, see if anything about “how to remove” comes up, and if not click away.

5. Put on the Webshots screen saver or any other screen saver that updates daily.

These types of screensavers will rob you of processor cycles and slow your computer down, but if you care more about that “kitties and puppies” screensaver then those cycles it probably doesn’t really matter. Plus when you’ve got the screensaver running, it doesn’t really matter does it? Note that the number of running processes I have is 20 and I’m writing this on a 5-year-old laptop. If you want it to last, keep the things your computer has to do to a minimum and it will be able to handle it. As new products come out, they assume the highest level of computing power is available to them, and that the entire purpose of the machine is to run them. Every so often, go to Start > Run, type msconfig, and slide over to the “Startup” tab. Make sure not to disable your antimalware protection, but disable everything else. You don’t need anything running every time you start your computer, you can startup aim or myspace or daemon tools yourself. If you want to find out what all those programs in your Startup tab are, check out a list like this one here.

6. Run as many things in the background as possible; even for software you use only once in a while.

Jeff has a point here. If you have to have these things maybe it’s time for a leeter computer. Really, background tasks are fine, as long as they are not startup tasks and you actually need then to be running when they are. This includes daemon tools, BitTorrent, and Quicktime - just shut them down when you are done using them.

7. Don’t delete drivers from printers you threw away 5 years ago.

Since Windows Service Pack 2, the drivers are only initiated if you hook up the device. So make sure your Windows Updates are running and that there is nothing running when you start your computer and you should be fine.

8. Download animated cursors

Indeed they are annoying to others, and indeed they come with spyware, but that can easily be disabled with HijackThis, a free antimalware tool that lets you delete any customizations to the shell of your operating system. Even works with Linux!

9. Use the automatic viewer pane in your email program.

The answer to this conundrum lies in avoiding email programs altogether by using web-based email that’s reliable and has good storage, as well as a convenient user interface, and nice spam blockage. I recommend Gmail. Windows Mail now also has fantastic spam filtering. If you must use a program with the automatic viewer, set up some spam filters and be careful not to accidentally click on your junk mail folder while the viewer is on.

10. Blindly click on things without reading them.

This one rings true, too. You must always read the popups your firewall presents to you and always consider every flashing popup. Unless you use Stopzilla and adblock software. This removes all ads from websites, including annoying flashing ones, and Stopzilla has a global black/white list that’s tested by millions of users online, so chances are you won’t encounter a new piece of software.

11. Use Windows

If you’re in a position where using a non-Windows operating system is an option, switching operating systems is a drastic but very effective way to help reduce the number of viruses you’ll potentially have to deal with. Linux and other *nix versions have fewer users and thus are less often targets for virus writers. Add to that the fact that all of these OSs hold a special place in many virus writers hearts, and it’s not surprising they are frequently spared. If you’d like to look into Linux but don’t know where to start, you should consider installing a very popular version called Ubuntu. It has a simple setup and a user interface that is similar to Windows. As these OSs are not nearly as vulnerable to viruses, you can do many of the things above without worrying about the tips and tricks.

Saturday, April 28, 2007

DESKTOP JAVA GAMES

Here are some of Java (sun) Games offered;

Pharoah's Solitaire
If you love Solitaire, check out this spin on the classic game.

Vaults of Atlantis Slots
Visit this underwater casino and try your luck

WildSnake Arcade: Invasion Waves
No more bricks, no more breaks

Chess
Capture the king!

NEW MOBILE GAMES FROM JAVA

For you are looking for games for your mobile, Java (Sun) offered new version of their mobile games list below:

Downtown Texas Hold'em
Enjoy the ultimate wireless poker.

SimCity
Design and build the city of your dreams on your mobile phone.

Jewel Quest II
Enjoy hours of puzzle fun in the search for jewels!

3D Constructo Combat
Go constructo crazy!

Inca Quest
Discover the Incan treasure that you've been searching for!

EA SPORTS Madden 07
Take the field as your favorite NFL team and players.

24 Agent Down
Regain control of CTU headquarters.

Familiars
The destiny of creation lies in your hands.

Orcs & Elves
Escape to a place of adventure, mystery and sorcery!

Doom RPG
Are you ready to battle the cyber demons?

The Sims™ 2

The Sims 2 on mobile features completely unique storylines giving players the ability to customize and take control of their Sims. It offers a Create-A-Sim function, which enables players to create and customize their own Sims from a variety of components. The classic The Sims 2 gameplay allows players to satisfy their Sim's wants, buy objects, develop their Sim's careers and skills, and even develop relationships with other Sims. The intuitive 'one thumb' gameplay combined with an immersive 3D Sims world will let both old and new players enjoy the game of life on their mobile phone.

Available on:

Download Shockwave Player

Windows Version Download

File size: 2,737 K
Download Time Estimate : 6 minutes @ 56K modem
Platform : Windows
Version: Shockwave 10.2.0.021
Browser : Netscape or Netscape-compatible and Internet Explorer
Date Posted : 4/23/2007
Language : English, French, German

Installation Instructions

1. Click the "Download Now" button to begin installing Adobe Shockwave Player.

2. When asked, save the Installer to your desktop.

3. When the download is complete, locate the Installer and double-click on it. The Installer will launch and dialog boxes will lead you through the rest of the installation process.

4. When the Adobe Shockwave Player movie begins playing, your installation is successful.

If you have installation questions or need help troubleshooting the Adobe Shockwave Player, see Adobe Support Center.

Find answers about Adobe Shockwave Player privacy, licensing, developing Shockwave content, and more in list of Frequently Asked Questions (FAQ).

Sun Java Software is

What is Java Software?

Java software allows you to run applications called "applets" that are written in the Java programming language. These applets allow you to play online games, chat with people around the world, calculate your mortgage interest, and view images in 3D. Corporations also use applets for intranet applications and e-business solutions.

FREE DOWNLOAD HERE

Note: if you want to download a version for a system or browser other than the one you are on now, please use the manual download link below.

> Manual Download

> Help

After you download Java software, visit java.com to find the latest games, software, and music that run on Java technology.

Thursday, April 26, 2007

How to get free traffic to your blog

This is how you can get 100 free visits to your blog. If you are not already a member of BlogExplosion, join it now, then write a post in your blog with 3 active links to any of the blogs below (homepage or individual post page, ie., permalink). When you are done, comment in this post giving the link to the post and your BlogExplosion user-name, and I will transfer 100 credits (which means 100 visits) to your BlogExplosion account if your blog PageRank is 1 and above, and 50 credits if your blog PageRank is 0. You can write anything. You can praise them, just describe them, or even criticise them. However, the post must be a permanent post, and not deleted after you get your free credits.

Wednesday, April 25, 2007

Sun-Earth Relationship

The Sun is our nearest star. Nuclear reactions deep inside the Sun create the light and heat we need for our survival. Scientists think the Sun was born about five billion years ago. Although the Sun is consuming four million tonnes of hydrogen fuel every second, it is so large that it should continue to shine for another five billion years. By that time, it will have swollen into a red giant, causing the oceans to boil away and destroying all life on our planet.

The Sun's activity varies over an 11-year period. The number of sunspots and flares, and the radiation output, change over time. The most recent peak in its cycle of activity occurred in mid-2000 with a second peak at the end of 2001. Scientists are hoping that the two missions in ESA's Solar-Terrestrial Programme, SOHO and Cluster, will be able to tell them more about how the Sun works and how it affects the Earth. While SOHO studies explosions on the Sun and detects solar storms heading our way, Cluster will measure the effects of this activity on near-Earth space as the incoming energetic particles subject the magnetosphere to a buffeting.

The Sun as seen by SOHO on 14 September 1997 in extreme ultraviolet light.
The solar prominence, bottom left, has a temperature of some 70 000 °C.
The solar corona is hotter than a million degrees Celsius

Facts about the Sun

Distance From Earth	149 600 000 km
Diameter	1 392 000 km (= 109 Earth diameters)
Rotation Period at Equator	24.6 days
Surface Temperature	5500 ^oC
Core Temperature	15 million ^oC
Mass (Earth = 1)	333 000
Volume (Earth = 1)	1 300 000
Gravity (Earth = 1)	27.94

How the Sun affects our planet

The Sun affects our world in many ways. A continuous stream of atomic particles - the solar wind - pours out into space from the Sun at speeds ranging from 300 to 1000 kilometres per second (1800 times faster than Concorde!). Sometimes, explosions on the Sun send millions of tonnes of gas towards the Earth. These clouds of high energy particles can cross the 150 million kilometre gulf between the Sun and Earth in a few days. The most energetic particles of all, created by solar flares, can reach Earth in just 30 minutes.


An aurora: a product of charged particles radiated by the Sun interacting with the Earth's atmosphere	A solar Coronal Mass Ejection (CME) event as recorded by SOHO on 2 June 1998

When charged particles from the Sun enter Earth's upper atmosphere, they create shimmering curtains of coloured light, known as auroras, in the polar night sky. Other effects can be much more serious:

Solar storms affect Earth's ionosphere, causing disruption of short wave radio communications, navigation systems on ships and aircraft, and military radar systems
Surges in long electricity transmission lines may cause power and widespread blackouts, as happened in Quebec, Canada, in March 1989 when 6 million people were left without electricity due to a huge solar-induced magnetic storm
Damage to microchips and electrical discharges may cause satellites to stop operating, causing disruption of, for example, telephone, TV and data communication services
Radiation levels can become hazardous to astronauts and occupants of high flying aircraft
High energy particles hitting Earth's upper atmosphere can destroy the ozone layer, which protects us from harmful ultraviolet radiation
Solar storms have even been blamed for increased corrosion in oil pipelines
Solar energy output varies over the 11-year sunspot cycle. This may cause climate changes, which can affect vegetation growth and food supplies

source : http://sci.esa.int

Eye Classes of Photosensors

Where do the properties of the eye get involved?

It's know that the eye does not see all wavelengths equally. The eye has two general classes of photosensors, cones and rods.

Cones:
The cones are responsible for light-adapted vision; they respond to color and have high resolution in the central foveal region. The light-adapted relative spectral response of the eye is called the spectral luminous efficiency function for photopic vision, V(l) or V(wavelength). This empirical curve, first adopted by the International Commission on Illumination (CIE) in 1924, has a peak of unity at 555 nm, and decreases to levels below 10^–5 at about 370 and 785 nm. The 50% points are near 510 nm and 610 nm, indicating that the curve is slightly skewed. The V(l) curve looks very much like a Gaussian function; in fact a Gaussian curve can easily be fit and is a good representation under some circumstances. I used a non-linear regression technique to obtain the following equation:

More recent measurements have shown that the 1924 curve may not best represent typical human vision. It appears to underestimate the response at wavelengths shorter than 460 nm. Judd (1951), Vos (1978) and Stockman and Sharpe (1999) have made incremental advances in our knowledge of the photopic response.

Rods:
The rods are responsible for dark-adapted vision, with no color information and poor resolution when compared to the foveal cones. The dark-adapted relative spectral response of the eye is called the spectral luminous efficiency function for scotopic vision, V’(l). This is another empirical curve, adopted by the CIE in 1951. It is defined between 380 nm and 780 nm. The V’(l) curve has a peak of unity at 507 nm, and decreases to levels below 10–3 at about 380 and 645 nm. The 50% points are near 455 nm and 550 nm. This scotopic curve can also be fit with a Gaussian, although the fit is not quite as good as the photopic curve. My best fit is

Photopic (light adapted cone) vision is active for luminances greater than 3 cd/m². Scotopic (dark-adapted rod) vision is active for luminances lower than 0.01 cd/m². In between, both rods and cones contribute in varying amounts, and in this range the vision is called mesopic. There are currently efforts under way to characterize the composite spectral response in the mesopic range for vision research at intermediate luminance levels.

The Color Vision Lab at UCSD has an impressive collection of the data files, including V(l), V’(l), and some of the newer ones that you need to do this kind of work.

Difference of lambertian and isotropic

What is the difference between lambertian and isotropic?

Both terms mean "the same in all directions" and are unfortunately sometimes used interchangeably.

Isotropic implies a spherical source that radiates the same in all directions, i.e., the intensity (W/sr) is the same in all directions. We often hear about an "isotropic point source." There can be no such thing; because the energy density would have to be infinite. But a small, uniform sphere comes very close. The best example is a globular tungsten lamp with a milky white diffuse envelope, as used in dressing room lighting. From our vantage point, a distant star can be considered an isotropic point source.

Lambertian refers to a flat radiating surface. It can be an active surface or a passive, reflective surface. Here the intensity falls off as the cosine of the observation angle with respect to the surface normal (Lambert's law). The radiance (W/m2-sr) is independent of direction. A good example is a surface painted with a good "matte" or "flat" white paint. If it is uniformly illuminated, like from the sun, it appears equally bright from whatever direction you view it. Note that the flat radiating surface can be an elemental area of a curved surface.

The ratio of the radiant exitance (W/m²) to the radiance (W/m²-sr) of a lambertian surface is a factor of p or (pi) and not 2p or 2pi . We integrate radiance over a hemisphere, and find that the presence of the factor of cos(q) or (cos teta) in the definition of radiance gives us this interesting result. It is not intuitive, as we know that there are 2p steradians in a hemisphere.

A lambertian sphere illuminated by a distant point source will display a radiance which is maximum at the surface where the local normal coincides with the incoming beam. The radiance will fall off with a cosine dependence to zero at the terminator. If the intensity (integrated radiance over area) is unity when viewing from the source, then the intensity when viewing from the side is 1/p . Think about this and consider whether or not our Moon is lambertian. I'll have more to say about this at a later date in another place!

Quantities and units used in photometry

They are basically the same as the radiometric units except that they are weighted for the spectral response of the human eye and have funny names. A few additional units have been introduced to deal with the amount of light reflected from diffuse (matte) surfaces. The symbols used are identical to those radiometric units, except that a subscript "v" is added to denote "visual". The following chart compares them.

QUANTITY	RADIOMETRIC	PHOTOMETRIC
power	watt (W)	lumen (lm)
power per unit area	W/m2	lm/m2 = lux (lx)
power per unit solid angle	W/sr	lm/sr = candela (cd)
power per area per solid angle	W/m2-sr	lm/m2-sr = cd/m2 = nit

Now we can get more specific about the details.

The candela is one of the seven base units of the SI system. It is defined as follows:

The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 10¹² hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.

The candela is abbreviated as cd and its symbol is Iv. The above definition was adopted by the 16th CGPM in 1979.

The candela was formerly defined as the luminous intensity, in the perpendicular direction, of a surface of 1/600 000 square metre of a black body at the temperature of freezing platinum under a pressure of 101 325 newtons per square metre. This earlier definition was initially adopted in 1946 and later modified by the 13th CGPM (1967). It was abrogated in 1979 and replaced by the current definition.

The current definition was adopted because of several reasons. First, the freezing point of platinum (» 2042K) was tied to another base unit, the kelvin. If the best estimate of this point were changed, it would then impact the candela. The uncertainty of the thermodynamic temperature of this fixed point created an unacceptable uncertainty in the value of the candela. Second, the realization of the Pt blackbody was extraordinarily difficult; only a few were ever built. Third, if the temperature were slightly off, possibly because of temperature gradients or contamination, the freezing point might change or the temperature of the cavity might differ. The sensitivity of the candela to a slight change in temperature is significant. At a wavelength 555 nm, a change in temperature of only 1K results in a luminance change approaching 1%. Fourth, the relative spectral radiance of blackbody radiation changes drastically (some three orders of magnitude) over the visible range. Finally, recent advances in radiometry offered a host of new possibilities for the realization of the candela.

The value 683 lm/W was selected based upon the best measurements with existing platinum freezing point blackbodies. It has varied over time from 620 to nearly 700 lm/W, depending largely upon the assigned value of the freezing point of platinum. The value of 1/600 000 square metre was chosen to maintain consistency with prior standards. Note that neither the old nor the new definition say anything about the spectral response of the human eye. There are additional definitions that include the characteristics of the eye, but the base unit (candela) and those SI units derived from it are "eyeless."

Also note that in the definition there is no specification for the spatial distribution of intensity. Luminous intensity, while often associated with an isotropic point source, is a valid specification for characterizing highly directional light sources such as spotlights and LEDs.

One other issue before we press on. Since the candela is now defined in terms of other SI derived quantities, there is really no need to retain it as an SI base quantity. It remains so for reasons of history and continuity.

The lumen is an SI derived unit for luminous flux. The abbreviation is lm and the symbol is Fv. The lumen is derived from the candela and is the luminous flux emitted into unit solid angle (1 sr) by an isotropic point source having a luminous intensity of 1 candela. The lumen is the product of luminous intensity and solid angle, cd-sr. It is analogous to the unit of radiant flux (watt), differing only in the eye response weighting. If a light source is isotropic, the relationship between lumens and candelas is 1 cd = 4p lm. In other words, an isotropic source having a luminous intensity of 1 candela emits 4p lumens into space, which just happens to be 4p steradians. We can also state that 1 cd = 1 lm/sr, analogous to the equivalent radiometric definition.

If a source is not isotropic, the relationship between candelas and lumens is empirical. A fundamental method used to determine the total flux (lumens) is to measure Later on, we can use this "calibrated" lamp as a reference in an integrating sphere for routine measurements of luminous flux.

Lumens are what we get from the hardware store when we purchase a light bulb. We want a high number of lumens with a minimum of power consumption and a reasonable lifetime. Projection devices are also characterized by lumens to indicate how much luminous flux they can deliver to a screen.

Illuminance is another SI derived quantity which denotes luminous flux density . It has a special name, lux, and is lumens per square metre, or lm/m2. The symbol is Ev. Most light meters measure this quantity, as it is of great importance in illuminating engineering. The IESNA Lighting Handbook has some sixteen pages of recommended illuminances for various activities and locales, ranging from morgues to museums. Typical values range from 100 000 lx for direct sunlight to 20-50 lx for hospital corridors at night. Luminance should probably be included on the official list of derived SI quantities, but is not. It is analogous to radiance, differentiating the lumen with respect to both area and direction. It also has a special name, nit, and is cd/m2 or lm/m2-sr if you prefer. The symbol is Lv. It is most often used to characterize the "brightness" of flat emitting or reflecting surfaces. A typical use would be the luminance of your laptop computer screen. They have between 100 and 250 nits, and the sunlight readable ones have more than 1000 nits. Typical CRT monitors have between 50 and 125 nits.

Other photometric units

We have other photometric units (boy, do we have some strange ones). Photometric quantities should be reported in SI units as given above. However, the literature is filled with now obsolete terminology and we must be able to interpret it. So here are a few terms that have been used in the past.

Illuminance :

1 metre-candle = 1 lux

1 phot = 1 lm/cm2 = 104 lux

1 foot-candle = 1 lumen/ft2 = 10.76 lux

1 milliphot = 10 lux

Luminance : Here we have two classes of units. The first is conventional, easily related to the SI unit, the cd/m2 (nit).

1 stilb = 1 cd/cm2 = 104 cd/m2 = 104 nit

1 cd/ft2 = 10.76 cd/m2 = 10.76 nit

The second class was designed to "simplify" characterization of light reflected from diffuse surfaces by including in the definitions the concept of a perfect diffuse reflector (lambertian, reflectance r = 1). If one unit of illuminance falls upon this hypothetical reflector, then 1 unit of luminance is reflected. The perfect diffuse reflector emits 1/p units of luminance per unit illuminance. If the reflectance is r, then the luminance is r times the illuminance. Consequently, these units all have a factor of (1/p) built in.

1 lambert = (1/p) cd/cm2 = (104/p) cd/m2

1 apostilb = (1/p) cd/m2

1 foot-lambert = (1/p) cd/ft2 = 3.426 cd/m2

1 millilambert = (10/p) cd/m2

1 skot = 1 milliblondel = (10-3/p) cd/m2

Photometric quantities are already the result of an integration over wavelength. It therefore makes no sense to speak of spectral luminance or the like.

Quantities and Units in Radiometry

What are the quantities and units used in radiometry?

Radiometric units can be divided into two conceptual areas: those having to do with power or energy, and those that are geometric in nature. The first two are:

Energy is an SI derived unit, measured in joules (J). The recommended symbol for energy is Q. An acceptable alternate is W.

Power (a.k.a. radiant flux) is another SI derived unit. It is the derivative of energy with respect to time, dQ/dt, and the unit is the watt (W). The recommended symbol for power is F (the uppercase Greek letter phi). An acceptable alternate is P.

Energy is the integral over time of power, and is used for integrating detectors and pulsed sources. Power is used for non-integrating detectors and continuous sources. Even though we patronize the power utility, what we are actually buying is energy in watt-hours.

Now we become more specific and incorporate power with the geometric quantities area and solid angle

Irradiance (a.k.a. flux density) is another SI derived unit and is measured in W/m2. Irradiance is power per unit area incident from all directions in a hemisphere onto a surface that coincides with the base of that hemisphere. A similar quantity is radiant exitance, which is power per unit area leaving a surface into a hemisphere whose base is that surface. The symbol for irradiance is E and the symbol for radiant exitance is M. Irradiance (or radiant exitance) is the derivative of power with respect to area, dF /dA. The integral of irradiance or radiant exitance over area is power.

Radiant intensity is another SI derived unit and is measured in W/sr. Intensity is power per unit solid angle. The symbol is I. Intensity is the derivative of power with respect to solid angle, dF /dw . The integral of radiant intensity over solid angle is power.

Radiance is the last SI derived unit we need and is measured in W/m2-sr. Radiance is power per unit projected area per unit solid angle. The symbol is L. Radiance is the derivative of power with respect to solid angle and projected area, dF /dw dA cos(q) where q is the angle between the surface normal and the specified direction. The integral of radiance over area and solid angle is power.

A great deal of confusion concerns the use and misuse of the term intensity. Some folks use it for W/sr, some use it for W/m² and others use it for W/m²-sr. It is quite clearly defined in the SI system, in the definition of the base unit of luminous intensity, the candela. Some attempt to justify alternate uses by adding adjectives like field or optical (used for W/m²) or specific (used for W/m²-sr), but this practice only adds to the confusion. The underlying concept is (quantity per unit solid angle). For an extended discussion, I wrote a paper entitled "Getting Intense on Intensity" for Metrologia (official journal of the BIPM) and a letter to OSA's "Optics and Photonics News". A modified version is available on the web.

Photon quantities are also common. They are related to the radiometric quantities by the relationship Q_p = hc/l where Q_p is the energy of a photon at wavelength l , h is Planck's constant and c is the velocity of light. At a wavelength of 1 mm, there are approximately 5×10¹⁸ photons per second in a watt. Conversely, also at 1 mm, 1 photon has an energy of 2×10^–19 joules (watt-sec). Common units include sec^–1-m^–2-sr^–1 for photon radiance.

Projected area and solid angle

What is projected area?

Projected area is defined as the rectilinear projection of a surface of any shape onto a plane normal to the unit vector. The differential form is dAproj = cos(b) dA where b is the angle between the local surface normal and the line of sight. We can integrate over the (perceptible) surface area to get

Some common examples are shown in the table below:

SHAPE	AREA	PROJECTED AREA
Flat rectangle	A = L×W	Aproj= L×W cos b
Circular disc	A = p r² = p d² / 4	Aproj = p r² cos b = p d² cos b / 4
Sphere	A = 4 p r² = p d²	Aproj = A/4 = p r²

What is solid angle?

Plane angle and solid angle are two derived units in the SI system. The following definitions are taken from NIST SP811.

"The radian is the plane angle between two radii of a circle that cuts off on the circumference an arc equal in length to the radius."

The abbreviation for the radian is rad. Since there are 2p radians in a circle, the conversion between degrees and radians is 1 rad = (180/p) degrees.

A solid angle extends the concept to three dimensions.

"One steradian (sr) is the solid angle that, having its vertex in the center of a sphere, cuts off an area on the surface of the sphere equal to that of a square with sides of length equal to the radius of the sphere."

The solid angle is thus ratio of the spherical area to the square of the radius. The spherical area is a projection of the object of interest onto a unit sphere, and the solid angle is the surface area of that projection. If we divide the surface area of a sphere by the square of its radius, we find that there are 4p steradians of solid angle in a sphere. One hemisphere has 2p steradians.

The symbol for solid angle is either w , the lowercase Greek letter omega, or W , the uppercase omega. I use w exclusively for solid angle, reserving W for the advanced concept of projected solid angle (w cosq ).

Both plane angles and solid angles are dimensionless quantities, and they can lead to confusion when attempting dimensional analysis.

Radiometry and photometry

What is radiometry ?

Radiometry is the measurement of optical radiation, which is electromagnetic radiation within the frequency range between 3×1011 and 3×1016 Hz. This range corresponds to wavelengths between 0.01 and 1000 micrometres (m m), and includes the regions commonly called the ultraviolet, the visible and the infrared. Two out of many typical units encountered are watts/m2 and photons/sec-steradian.

What is photometry ?

Photometry is the measurement of light, which is defined as electromagnetic radiation which is detectable by the human eye. It is thus restricted to the wavelength range from about 360 to 830 nanometers (nm; 1000 nm = 1 mm). Photometry is just like radiometry except that everything is weighted by the spectral response of the eye. Visual photometry uses the eye as a comparison detector, while physical photometry uses either optical radiation detectors constructed to mimic the spectral response of the eye, or spectroradiometry coupled with appropriate calculations to do the eye response weighting. Typical photometric units include lumens, lux, candelas, and a host of other bizarre ones.

How do Radiometry and photometry differ

The only real difference between radiometry and photometry is that radiometry includes the entire optical radiation spectrum, while photometry is limited to the visible spectrum as defined by the response of the eye. In my forty years of experience, photometry is more difficult to understand, primarily because of the arcane terminology, but is fairly easy to do, because of the limited wavelength range. Radiometry, on the other hand, is conceptually somewhat simpler, but is far more difficult to actually do.

Tuesday, April 24, 2007

Blog-Post Template

What is a Blog-post template?

Post templates help users save time by pre-formatting the post editor. Some users like their posts to be formatted in a certain way; here's an example where the user links to an article on the first line, then quotes it below:

Software for Blog