The history of the bar code
A The first step toward today's bar codes came in 1948, when Bernard Silver, a graduate student in the USA, overheard a conversation in the halls of Philadelphia's Drexel Institute of Technology. The president of a food chain was pleading with a professor to undertake research on a method of capturing product information automatically at store checkouts. The professor turned down the request, but Bernard Silver mentioned the conversation to his friend Norman Woodland, a twenty-seven-year-old teacher at Drexel.
B The problem fascinated the two friends, and they set about thinking of a solution. Their first idea was to use patterns printed with an ink that would glow under ultraviolet light, and they built a device to test the concept. It worked, but the printing costs were high and the patterns faded over time. Nonetheless, they were convinced they had a workable idea. After several months of work they came up with the linear bar code, using elements from two established technologies: Morse code, in which letters and numbers are coded into a system of dots and dashes, and the method used to record soundtracks in movies. Silver and Woodland patented the idea in 1952, describing their invention as 'article classification... through the medium of identifying patterns'. But the cost, together with the fact that their scanning equipment was rather unreliable, made the idea a non-starter at that time.
C Scanning systems made little progress until the 1970s, when lasers became affordable. Following this, various systems came into use around the world in stores, libraries, factories, and the like, each with its own proprietary code, but there was no standardization. A consortium of grocery manufacturers and retailers therefore set up a committee to look into bar codes, and to standardize what became known formally as the Universal Product Code (UPC). At the heart of the committee's guidelines were a few basic principles. To make life easier for the cashier, bar codes would have to be readable from almost any angle and at a range of distances. Because they would be reproduced by the million, the labels would have to be cheap and easy to print. And to be affordable, automated checkout systems would have to pay for themselves in two and a half years.
D The committee considered more than a dozen versions of bar codes, including one based on multi-colored dots and another using a circular bull's eye design with lines radiating from a central point. On April 1, 1973, they unanimously agreed on a standardized UPC, a combination of black and white lines and numbers, based on Woodland and Silver's idea but developed by George Laurer at IBM. Alan Haberman, who headed the subcommittee as president of First National Stores, described the bar code as a kind of world language that worked for everyone. He recalls proudly, 'We showed that it could be done on a massive scale, that cooperation… was possible for the common good, and that business didn't need the government to shove them in the right direction.'
E The investment involved in the bar-code revolution was huge. Each of the tens of thousands of grocery outlets in the US had to spend at least $200,000 on new scanning equipment. Chains had to install new data processing centers and retrain their employees. Printers had to develop the new types of ink, plates, and other technology to reproduce the code with the exact tolerances it requires, and manufacturers had to spend millions of dollars a year on the labels.
F On June 26, 1974, all the tests were done, all the proposals were complete, all the standards were set, and at a supermarket in Ohio, a single pack of Juicy Fruit chewing gum became the first retail product sold with the help of a bar-code scanner. Decades of schemes and billions of dollars in investment now became a practical reality. The bar code on any product could be read and understood in every suitably equipped store.
G The advantages of the system were not clear immediately, as wholesalers, retailers and customers remained suspicious. Some customers believed bar codes were a form of surveillance. During the early weeks, Business Week magazine ran the headline 'The Supermarket Scanner That Failed'. However, the benefits eventually became apparent. 'It turns out there were massive savings in labor and other areas,' Haberman says. These included checking out items at twice the speed compared to using traditional equipment, which meant shorter lines. And it did not take supermarkets too long to see that, as well as vastly improving customer service, the bar code could hugely reduce the amount of time spent checking inventory.
H Now, every day more than 5 billion bar codes are scanned in retail outlets throughout the world. Passengers' luggage is tagged with bar codes by airlines. Staff attach them to babies to ensure the right babies go home from hospitals with the right mothers. Runners in major marathons set off with bar codes on their vests, and librarians rely on them. Tiny bar codes have even been mounted on bees by researchers to track their movements.
I As for that original pack of Juicy Fruit, it is now, unchewed and unopened, in the Smithsonian Institution’s National Museum of American History in Washington.
Learning from the Romans
How an ancient building material is influencing modern construction
A In a quest to make concrete more durable and sustainable, an international team of geologists and engineers has found inspiration in the concrete used by the ancient Romans. The chemical secrets of Roman concrete have been uncovered in samples taken from a concrete Roman breakwater. A breakwater is a barrier that is built out into the sea to protect coasts and harbors from the force of waves. This particular breakwater has spent the last 2,000 years submerged in seawater. The international team of researchers that collected the samples was led by Paulo Monteiro, a professor of civil and environmental engineering at the University of California, Berkeley. Analysis of samples from the ancient underwater site in Pozzuoli Bay near Naples in Italy pinpointed why the best Roman concrete was superior to most modern concrete.
B Concrete was the Roman Empire's construction material of choice. It was used in land monuments such as the Pantheon in Rome, as well as in underwater and partially underwater coastal and harbor structures. Monteiro and his team were particularly interested in how the coastal and harbor structures endured the unforgiving saltwater environment. Chemical analysis of Roman concrete showed that it differs from the modern kind in several ways. One is the content of the cement that binds the material in the concrete. The most commonly used cement in recent decades has been Portland cement. Portland cement is a compound of calcium, silicates, and hydrates (C-S-H). However, analysis of Roman concrete shows that it contains a significantly different cement. Roman cement contains aluminum, which is not found in Portland cement, and less silicon than is found in Portland cement. The resulting calcium-aluminum-silicate-hydrate (C-A-S-H) is an exceptionally stable cement.
C The recipe for the contents of Roman concrete was first described around 30 BC by Vitruvius, an engineer for the Roman Emperor Augustus. Volcanic ash was one of the ingredients, and it is now understood that this is crucial, as it is volcanic ash that contains the aluminum that ultimately gives Roman concrete its great durability. The Romans devised an efficient method of making concrete for coastal structures. They combined volcanic ash with lime, which added the calcium to the mix. This was then packed, together with stones and chunks of rock, into wooden molds, which were then immersed in seawater. The seawater instantly triggered a hot chemical reaction. The lime was hydrated by the seawater, which means that it incorporated water molecules into its structure, and reacted with the volcanic ash to cement the whole mixture together. This reaction formed the concrete that was used to build some of the most enduring structures in Western civilization.
D According to Marie Jackson, a member of the research team, Roman concrete is one of the most durable construction materials on the planet, and that was no accident. Shipping was the lifeline of political, economic, and military stability for the Roman Empire, so constructing harbors that would last was critical. 'Over time, the Romans used less and less concrete.' 'As the Roman Empire declined, and shipping declined, the need for the seawater concrete declined,' said Jackson. 'You could also argue that the original structures were built so well that, once they were in place, they didn't need to be replaced,' she added.
E Producing Roman concrete also left a smaller carbon footprint than its modern counterpart. 'It's not that modern concrete isn't good—it's so good we use 19 billion tons of it a year,' says Monteiro. 'The problem is that manufacturing Portland cement accounts for seven percent of the carbon dioxide that industry puts into the air.' Portland cement holds most modern concrete together. However, making Portland cement releases carbon dioxide into the atmosphere from burning fuel in order to heat a mix of limestone and clays to 1,450 degrees Celsius. The production of Roman concrete, however, was much cleaner, as less heat was needed. A temperature that was a third lower than that required for making Portland cement was sufficient for making Roman concrete.
F Some modern concrete no longer contains Portland cement; instead, fly ash is used, which causes fewer greenhouse gas emissions. Fly ash is a waste product from burning coal, and the researchers are investigating whether volcanic ash would be a good, large-volume replacement in countries that cannot access fly ash easily. 'There is not enough fly ash in this world to replace half of the Portland cement being used,' said Monteiro. 'Many countries don't have fly ash, so the idea is to find alternative local materials that will work, including the kind of volcanic ash that Romans used. Using these alternatives could replace 40 percent of the world's demand for Portland cement.'
G Cutting greenhouse gas emissions is one powerful incentive for finding a better way to provide the concrete the world needs; another is the need for stronger, longer-lasting buildings, bridges, and other structures. 'In the middle 20th century, concrete structures were designed to last 50 years, and a lot of them are on borrowed time,' Monteiro says. 'Now we design buildings to last 100 to 120 years.' Yet Roman harbor installations have survived 2,000 years of chemical attack from seawater and wave action. Stronger, longer-lasting modern concrete may be the legacy of a deeper understanding of how the Romans made their incomparable concrete.
Images and Places
A new research method uses photography to try to explain why people form an attachment to certain places
A Human beings naturally become attached to places they visit or inhabit and these emotional attachments have become increasingly important in research on recreation sites and activities. Research into this phenomenon is called 'sense-of-place research'. This research has employed a variety of approaches to gauge people's feelings toward a place, including surveys and personal interviews, but so far has not used photo-based methods. However, Visitor Employed Photography (VEP), used to capture visitor perceptions of landscape and recreational quality, represents a potential innovation in sense-of-place research.
B A 'place' is a setting that we give meaning to based on the personal experiences, relationships and feelings we associate with it. A crucial distinction that needs to be made is between the more subjective concept of attachment and the symbolic 'meanings' or labels we use to describe the type of place a setting represents. Is, for example, a multiple-use forest area a wilderness? A playground? A workplace? Symbolic meanings are important in that they form the basis of our attachment to a place: we attribute meaning to our settings, and in turn become attached to the meanings (Stedman, 2003).
All settings can have multiple meanings depending on how we encounter them. Some researchers suggest that, because meaning emerges through individual experience, for example 'my camping trip', place meanings are completely individualistic: a given setting such as a park will contain as many different meanings as there are people using the setting (Meinig, 1979). Others, however (e.g. Grieder & Garkovich, 1994), assert that meanings are based on social categories and therefore are shared by others within these categories. For example, farmers share certain meanings for a plot of land that are distinct from those of real estate developers or hunters.
C Clearly, place attachment is built through familiarity with a place over a period of months or even years. Relph (1976) describes sense-of-place attachment as the steady accumulation of events within a setting; this creates 'home places'. According to this view, those who have participated fully in the life of the home or community, or have accumulated a series of everyday events in a setting, will have the strongest attachment to it. Extended residence in a place tends to make us feel toward it almost as a living thing, affecting our emotions in the same way as a family would (Ryden, 1993). However, Tuan (1977) notes that a sense of place may also develop quite rapidly in 'chosen places', where dramatic landscapes and intense experiences can lead to an immediate attachment. Indeed, many settings, especially those that attract visitors, may simultaneously exist as home places and chosen places.
D Clearly we are dealing with a complex phenomenon and photo-based research methods may help us to understand it better. In VEP, tourists are asked to take photographs. This technique has primarily been used to assess the perceptions of visitors to parks and recreation places. Haywood (1990) describes several benefits of VEP. Photography is an enjoyable, familiar activity to tourists which helps to sharpen observation and identify specific locations that are important. It can give clearer ideas on elements that are liked or disliked and also facilitates comparisons between places.
E However, several methodological issues need to be taken into account. First, who should take the photographs? VEP research typically involves visitors or tourists but, when applied to questions of attachment to a community, this approach has potential pitfalls. Chenoweth (1984) notes that research subjects may take photos that represent only a part of their entire recreational experience. This tendency probably relates to unfamiliarity with the setting. For example, when researchers assign the task of photographing a travel route with which respondents are not familiar, participants may save too many pictures and then use them all up at the end of their visit, even if there is no suitable material. Markwell (1997) noted an opposite tendency in his study of pictures taken on a nature tour: beginnings of excursions were over-represented, due perhaps to the initial novelty of the trip. Furthermore, Haywood (1990) suggests that compressing the photo-taking period into a single day (as he did in his work) may result in an over-representation of tourist icons rather than ordinary places.
In contrast, Yamashita (2002), when focusing on local residents' perceptions of the qualities of the water around them, noted that residents may have more difficulty expressing visual appeal than visitors, precisely because they are insiders and less conscious of aesthetic qualities. When addressing complex attachment to landscape, we would expect, however, that familiarity ought to increase the validity of the items selected to represent sources of attachment. We also expect that photographs taken by local residents will represent a wider range of phenomena than pictures taken by transient visitors.
F But how should the photographs be interpreted? Goin (2001) notes that with every photo taken 'a fiction is created ... but presents to the uninformed an overwhelming conviction of fact' (p. 363). By implication, what photos appear to be and what they really represent may be very different things, and some follow-up helps to uncover the intended meanings of the participant. Yamashita (2002) notes the utility of asking respondents to provide descriptions of each photo in a notebook or diary. These elaborations are helpful, but in cases of complex phenomena, an interview may help participants clarify their intentions (Markwell, 1997).