Science & technology

Ice power: Electric Power Research Institute, TVA and Volunteer Energy are conducting a joint test of the 'Ice Bear' in Knoxville, Tennessee. Neyland Stadium can be seen in the background. Credit: Courtesy of Ice Energy

Over the next few weeks, a consortium of municipal utilities in California will begin retrofitting government offices and commercial properties with systems that use ice made at night to replace air-conditioning during the day. It's part of a pilot program for the devices, which are built by Windsor, CO-based Ice Energy. If widely deployed, they could reduce fuel consumption by utilities by up to 30 percent and put off the need for new power plants.

The first devices will be installed on about two dozen city-owned buildings in Glendale, CA, under the plan being coordinated by the Southern California Public Power Authority. Over the next two years, the 11 participating utilities will install 1,500 of the devices, providing a total of 53 megawatts of energy storage to relieve strain on the region's electrical grid. The project is the first large-scale implementation of Ice Energy's technology.

Each Ice Energy device is designed to make ice overnight, when demand for electricity is low, using a high-efficiency compressor to freeze 450 gallons of water. Around midday, the cooling mode kicks in, and the device shuts off the building's regular air conditioner for a six-hour cycle. It pipes a stream of coolant from the slowly melting block of ice to an evaporator coil installed within the building's heating, ventilation, and air-conditioning blower system. Once the ice is melted, the air conditioner returns to normal operation. Brian Parsonnet, Ice Energy's chief technology officer, says the Ice Bear can cut a building's power consumption by 95 percent during peak hours on the hottest days.

Cutting demand for electricity during peak hours reduces the need to build new power plants. It also allows utilities to rely on their most efficient power plants, says Ronald Domitrovic, a senior project manager for electric utilization at the Electric Power Research Institute. He says that when utilities fire up their "least efficient, oldest, and least desirable" generating resources to meet peak demand, every increment of increased power on the grid sends costs surging, whether one is talking fuel costs, greenhouse gas emissions, or service reliability. However, at night, utilities draw on their most efficient power plants, which use less fuel than power plants used only during peak hours. The utility also saves energy at other points in the grid--for example, cooler power lines at night transmit electricity more efficiently.

Domitrovic says systems that use ice or cold water on a large scale to provide cooling for campuses and large buildings have "been around for some time." But he says these are usually "expensive one-off units, designed specifically for the building," and that the smaller modular thermal storage systems that Ice Energy provides "can be deployed with relative simplicity" to serve one- or two-story commercial buildings. Ice Energy says that cooling units housed at distributed sites can be networked, presenting utilities with a resource that can be dispatched as needed to help manage demand on the grid.

Parsonnet says the per-unit production cost for the Ice Energy systems has come down from $15,000 for its inaugural model to just $5,000 today. David Walden of SCPPA says that the current models are "cost competitive" with other options for reducing peak power demands, including renewable energy sources such as solar power.

The Ice Energy systems could help integrate more renewable energy into the grid, says Craig Kuennen, marketing manager and project sponsor of Glendale Water and Power, the utility heading up the Glendale portion of the project. He says southern California "has significant wind resources, and those come in at night, when we would be making ice." The Ice Energy systems would provide demand for that wind power, which might otherwise be wasted because of low demand at night.

Copyright Technology Review 2010.

Last month, Facebook finally crossed a line. The company announced that it would make certain user information--including a user's name, hometown, education, work, and "likes" and "dislikes"--permanently public.

Facebook's default privacy policy has gradually shifted to expose more user data to the wider Web, but the reaction to this latest change has been significant. Last week, a collection of European data-protection authorities known as the Article 29 Working Group sent Facebook a letter chastising the company for not allowing users to limit access to their social data. The letter follows a similar criticism of Facebook by several members of congress, such as Sen. Charles Schumer, D-NY, over the past month. The reaction from privacy advocacy groups, and from many of Facebook's users, has also been vocal.

Some experts also say that the increase in information disclosure could have a serious side-effect--opening up new opportunities for hackers. Kevin Johnson, a senior researcher with security firm InGuardians, uses Facebook as a starting point for his job: testing companies' network security. Many times, he says, the most significant vulnerabilities are not in hardware or software, but in a users' use of social networks. The information leaked on social networking sites can be used to impersonate a legitimate person, in order to recover a password, for example; or to trick users into opening a malicious file by making it appear to come from a friend or a colleague.

"As a penetration tester--as an attacker--Facebook's privacy settings have made my job easier," Johnson says. "In the past, before two years ago, we had to trick people into running a [rogue] application [to collect data]. Now, the majority of people out there--the bulk of Facebook--run under default privacy settings."

Pushed by a need to monetize the data entered by users, Facebook has increasingly loosened its privacy policies. In 2005, the company's original policy stated that no information would be shared with people "who [do] not belong to at least one of the groups specified by you in your privacy settings." By 2010, the policy had changed to one that focuses on sharing much more information, stating that applications and Web sites "will have access to General Information about you." The text of the company's privacy policy has grown nearly 500 percent and users are now required to navigate some 50 different privacy settings.

"Facebook says that they are introducing more privacy settings because they want to give users more control, but what they have done is make things more confusing," says Fred Stutzman, a privacy researcher and PhD candidate at the University of North Carolina at Chapel Hill. "Over time they have made changes that make people's information more open, because that is how they drive the use of the network."

"This is something that is different from how Facebook had been operating," says Kurt Opsahl, a senior staff attorney with the Electronic Frontier Foundation. "In the past, they encouraged sharing that information, but now they have taken information that many people consider private and made it public, and they did so in a very heavy-handed way."

Yet, as Facebook has grown, users have become savvier about their data security, Stutzman says. Students at UNC Chapel Hill, for example, have increasingly opted to set their Facebook privacy to the highest possible setting, with almost 60 percent of students using the "Friends Only" setting in 2008 compared with less than 20 percent in 2005. Stutzman says that people have to overcome their preference to run under the default settings and opt not to change them.

Alessandro Acquisti, associate professor of information science and policy at Carnegie Mellon University, argues that Facebook is likely counting on that psychology to limit the number of people who ratchet up the privacy settings. "What is happening, it is almost a bait and switch technique," he says. "Every time they change the status quo, they are getting people more and more adjusted to the habit of disclosing information. If you told people five years ago that all these different fields are public, they would say, 'No way.' "

Facebook says that some information--a person's name, her network of connections, and pages that she likes and dislike have always been public. The user's photo, gender, and current city have all been added to the must-be-public profile information, the company acknowledges, but it says that only a small fraction of users are changing their settings to restrict access to information.

"The overwhelming majority of users have made all of this information available to everyone," a spokesman says. "We've found that the small percentage who have restricted any of this information have intended to prevent contact from nonfriends."

However, Facebook may not find an easy way out of the current controversy. In February 2009, when users were upset about other changes to its terms of service, the company created its Facebook Principles, a list of promises of how the company would treat its users and their data, including that "people should own their information, they should have the freedom to share it with anyone they want and take it with them anywhere they want, including removing it from the Facebook Service."

The company has failed to live up to those principles, says the EFF's Opsahl. "It is not just a matter of, can Facebook weather the storm of criticism and keep their users--they have a real situation here," Opsahl says. "But they have an opportunity as well. They can try and fix this problem and regain their users' trust."

Copyright Technology Review 2010.

DNA assembly line: An atomic force microscope image shows gold nanoparticles on a DNA track. Credit: Courtesy of Ned Seeman

Its precise structure and ability to bind with other molecules makes DNA an attractive scaffolding material for nanotech researchers. Scientists have already used DNA to construct two-dimensional patterns, three-dimensional objects, and simple shape-changing devices. Now two teams of researchers have separately made complex programmable machines using DNA molecules.

Researchers from Columbia University, Arizona State University, and Caltech have made a device that follows a programmable path on a surface patterned with DNA. Meanwhile, researchers from New York University, led by DNA nanoarchitecture pioneer Ned Seeman, have combined multiple DNA devices to make an assembly line. The nano contraption picks up gold nanoparticles as it tumbles along a DNA-patterned surface.

The two machines, described in today's Nature journal, are a possible step forward in making DNA nanobots that could assemble tiny electrical and mechanical devices. DNA robots could also put together molecules in new ways to make new materials, says Lloyd Smith, a chemistry professor at the University of Wisconsin-Madison. "Robots might have the ability to position one molecule in a particular way so that a reaction happens with another molecule which might not happen if they randomly collide in solution," he says.

In the past, researchers have made simple machines such as tweezers and walkers that have also been fashioned from DNA. Tweezers open and close by adding specific DNA strands to the solution. Walkers are molecules with dangling strands, or legs, that bind and detach from other DNA strands patterned on a surface, in effect moving along the surface.

The nano walker made at Columbia University is a protein molecule decorated with three legs--single-stranded DNAzymes, synthetic DNA molecules that act as enzymes and catalyze a reaction. The legs bind to complementary DNA strands on a surface. Then they catalyze a reaction that shortens one of the surface strands, so that its attachment to the leg becomes weaker. That leg lets go and moves on to the next surface strand.

The walker follows a track of strands that the researchers pattern on the surface. It can take up to 50 steps--compared to the two or three steps taken by previous walkers. It stops when it encounters a sequence that cannot be shortened. "We show how to program [the walker's] behavior by programming the landscape," says Milan Stojanovic, a biomedical engineer at Columbia University who developed the walker. "It enables us to think about adding further complexity: more than one molecule interacting and more complicated commands on the surface. What we hope to do eventually is to be able to [use nanobots to] repair tissues."

Seeman and his colleagues at New York University combine three different DNA components to make an assembly line. They have DNA path, a walker, and a machine that can deliver or hold back a cargo of a molecule of gold. The machine is a DNA structure that can be set up to either put a gold nanoparticle-laden strand in the path of the walker or away from it. The walker has four legs and three single-stranded DNA hands that can bind to the gold.

The researchers demonstrated a system in which the walker passes three machines, each carrying a different type of gold particle. Each machine can be set up to either deliver its cargo or keep it, giving a total of eight different ways in which the walker can be loaded, leading to eight different products.

The advances represent continuing success in creating nano devices with increasingly complex functions. "[We're] moving from individual entities that do something interesting to systems of entities working on something with a more complex behavior and function," Smith says.

Copyright Technology Review 2010.

Identity parade: A concept browser designed by Mozilla would let users control a single identity for logging in to different websites. Credit: Mozilla Foundation

The race to own your virtual identity is on. In announcements made just days apart at the end of April, Facebook and the Mozilla Foundation launched parallel efforts to extend the way users are identified and connected on the Web.

The two approaches are fundamentally different. Facebook's Open Graph Protocol uses the oAuth standard, which lets a website identify a user via a third-party site without exchanging sensitive information. Facebook--whose 400 million active users make it the world's largest social network in the world--stands to benefit as other sites come to rely on the information it holds about users and their social connections.

The approach taken by the Mozilla Foundation, which makes the Firefox browser, comes in the form of a suite of browser extensions. One of the extensions, called Account Manager, can replace all of a user's online passwords with secure, computer-generated strings that are encrypted and protected with a single master password. Mozilla's identity extensions can interact with other identity standards, including OpenGraph, oAuth, and OpenID, a standard that allows any website or Web service provider to host a social network-style profile of a user. The goal of the Mozilla Foundation's efforts is to establish a set of open standards and protocols that could be implemented in any browser or website.

As much as possible, identity would be moved out of the webpage itself and into the "chrome" of the browser--the parts around of the webpage. Logging in and out of sites would be accomplished through buttons at the top of the browser that would activate secure protocols--rendering the process of creating and memorizing usernames and passwords obsolete.

"Every user of the Internet today is expected to describe themselves to every site they go to," says Mike Hanson, principal engineer at Mozilla Labs. Inevitably, Hanson says, this leads to confusion and security holes, such as passwords that are identical across multiple sites.

The solution, according to Hanson, is to let the browser itself manage user identity. Weave Sync, another Mozilla extension, is designed to enable that vision. It stores encrypted versions of a growing list of data on a Mozilla-hosted server (or any user-specified server), including a person's history, preferences, bookmarks, and even open tabs, which can be synced across two or more browsers. This allows users to have the same browser workspace on any device that supports Firefox or its mobile equivalent, Fennec. There's even a prototype for the iPhone, built on top of Apple's Safari browser.

Last fall Mozilla Labs also commissioned Chris Messina, at the time a researcher in residence at Mozilla Labs, to design a Web browser that would manage the other half of online identity--a user's social graph. In Messina's mock-ups, a user can interact with people on the Web in ways that go beyond what OpenID or Facebook's OpenGraph currently offer. "The idea of a social browser is important to me because it's the single point of integration for all websites," says Messina. "It's the one thing that knows who you are across all social experiences."

Messina's designs envision a browser that lets users "follow" other users by viewing all of their relevant information streams--Facebook, Twitter, Flickr, etc.--collected into a single browser tab stamped with that user's profile picture. A similar interface could also be used to control exactly what personal information other people and websites have access to. This could allow, for instance, a user to change her shipping address across any number of sites at once, or to control which version of their identity a particular groups of friends can access. "I'm not interested in the [Mark] Zuckerberg approach, where privacy doesn't exist anymore," says Messina, referring to the CEO of Facebook.

Both Facebook and the Mozilla Foundation will face challenges in pushing their own vision of online identity. John Mitchell, a professor of computer science at Stanford, says the most significant barrier will be the adoption of suitable protocols. Before such protocols can be standardized and rolled into, for instance, the next version of HTML, Web developers are going to have to be willing to experiment.

"What I've seen from a lot of companies is an attempt to guess the end solution and build that only," says Mitchell. "It would be better if, instead, we had an open architecture where people could try many different approaches."

If the new Mozilla software and Messina's designs are sufficiently popular with users and developers (not to mention the influencers who sit on the boards of standards committees like the World Wide Web Consortium), then the foundation's technology could find its way into the regular release of Firefox and perhaps, ultimately, into other browsers.

To Messina, just drawing up the blueprints for such technology was an important first step. "We're further away from the death of the password than I'd like to be, but it's a nice goal to aim for," he says.

Copyright Technology Review 2010.