Cognitive radios overcome incompatibilities
Cognitive radios present an exciting new frontier for the world of wireless telecommunications. Virginia Tech’s Center for Wireless Telecommunications (CWT) recently received a three-year National Science Foundation grant to extend its work in the field of cognitive radio to the network level.
Center Director and Alumni Distinguished Professor Charles W. Bostian explains CWT’s approach to cognitive radio: “The new cognitive radios are similar to living creatures in that they are aware of their surroundings, understand their own and their user’s capabilities, and the governing social constraints.”
The radio’s actions arise from a rational process that predicts probable consequences and it remembers all of its past failures and successes. Basically, the cognitive engine is a brain that reads the radio’s “meters” and turns the radio’s “knobs” in order to get the desired outcome.
In the aftermath of a major disaster, like the one in New Orleans with hurricane Katrina, firefighters, police officers, and other first-responders from many jurisdictions converge on the scene. The radio systems used by the different jurisdictions are rarely able to communicate. At best, extensive re-programming is required; often the officers are reduced to shouting from one vehicle to another or sending messengers.
Cognitive radio offers a much better solution. A first-responder’s cognitive radio will recognize the signals of the other units that are on the scene and configure itself to talk to any that the emergency responder selects. The radio will also be able to serve as a translator between two incompatible systems, allowing them to talk to each other through it.
The research at the CWT makes it possible for all cognitive radios to be connected in a network where that information can be shared amongst the group. Instead of just one cognitive radio working alone, there will now be a whole network working and sharing information in a “cognitive network.”
- Judy Hood, Center for Wireless Telecommunications
Big picture helps preserve history
Virginia Tech's Center for Geospatial Information Technology is assisting the American Association for State and Local History (AASLH) by developing maps and a GIS database of historical organizations in the areas affected by Hurricane Katrina.
AASLH, headquartered in Nashville, Tenn., provides leadership service and support for its member groups, which preserve and interpret state and local history
The Center for Geospatial Information Technology (CGIT) completed mapping 200 of the 248 address sites sent to it by the AASLH. The points placed onto maps allowed the association to view the pattern of their participating organizations in the Katrina cleanup region, and to guide their assistance efforts to those historical sites.
“After several passes through the addresses to remove post office boxes and other non-locatable entries, and with the help of many volunteer students from the departments of Geography and Civil and Environmental Engineering, the CGIT was able to provide locations for approximately 80 percent of those organizations to assist the AASLH in assisting their members after Katrina,” says geography professor Bill Carstensen Jr.
He says that the before and after information and maps that detail damage to infrastructure helped the association prioritize assistance to those organizations that are protecting significant U.S. historical sites and collections. “The maps will accurately locate important sites and organizations that are involved in the preservation of Gulf Coast history. We are preparing the maps here at our Center for Geospatial Information Technology as a service to the AASLH.”
Randy Dymond, director of the geospatial center, says, “We have some good capabilities and wanted to help in any way we could.”
Created in 2003, Virginia Tech’s Geospatial Information Technology Center has assisted the Commonwealth of Virginia with its hazard mitigation plan, the nation’s capital with its Critical Infrastructure Program, and communities with smart growth.
“Faculty in various departments at Virginia Tech share their expertise to integrate spatial awareness in intelligent data collection methods, in-field analysis, modeling and simulation, visualization, and a host of other techniques in a wide variety of uses,” says Dymond, associate professor of civil and environmental engineering and founding director of the center.
Faculty members from six colleges contribute expertise for agriculture, infrastructure and transportation, wireless communications, environmental management, public health, homeland security, and smart growth.
“Our goal is to use our collective expertise to help solve problems using geospatial technologies in ways that haven’t been possible until now,” says Dymond.
Engineers strive to translate hurricane simulations into building codes
When the media reports that the general public is breathing a sigh of relief that damage from Hurricane Rita to the Gulf Coast area was only about $8 billion, things seem to be out of whack – until that number is compared to the $200 billion estimation of damages from Hurricane Katrina just a few weeks previous.
However, if you were a member of Louisiana's Cameron Parish, where every home in the Holly Beach community and 90 percent of the homes in the town of Cameron were demolished, there is no sigh of relief.
After the 2005 season, Louisiana, Mississippi, and Texas might want to look to their neighbor to the east, Florida, normally one of the hardest hit states by hurricanes. In 1999, its legislature created a series of tools to stabilize the economy and the insurance industry, as well as to prevent or reduce losses during hurricanes. One offshoot of its enactments was the Florida Coastal Monitoring Program (FCMP). During the 2004 hurricane season, when Florida was hit with four major hurricanes, field measurements of wind loads conducted by FMCP revealed “they exceeded the provisions of the building codes,” says Muhammad Hajj, professor of engineering science and mechanics (ESM) at Virginia Tech.
Hajj and his colleague, Henry W. Tieleman, also of ESM, are working in cooperation with Clemson University, using its wind tunnel to simulate the ground level wind velocity, wind forces on structures, and the effectiveness of wind-resistant structural retrofits.
“Because the current building code provisions for wind loads are based on the compression of many wind tunnel observations into just a few numbers, the question arises as to what constitutes a proper simulation of the flow in the atmospheric surface layer and associated wind loads on low-rise structures. We also still need to know what procedures should be followed in translating pressure coefficients as measured in wind tunnel simulations to full scale applications,” Hajj says.
The FCMP and the Institute for Business and Home Safety are interested in how Hajj and Tieleman analyze the peak wind loads. “Because wind tunnel experiments can be repeated many times and hurricane wind gusts and full-scale measurements usually consist of one record, a probabilistic measure should be associated with measured peak levels,” Hajj says. “This is even more proper because of the inability to match all parameters of wind turbulence in wind tunnel simulations.”
As for simulating wind loads using computers, Hajj says that “we still need faster computers and more memory to simulate the turbulence in the wind and its interaction with structures.”
The approach and results of the work conducted by Hajj and Tieleman will ultimately be incorporated into regional and national building codes.
- Lynn Nystrom, College of Engineering
Innovative roof vent combats hurricane-force winds
High winds can rip off a roof in minutes. So researchers from the Virginia Tech College of Architecture and Urban Studies and College of Engineering and from industry invented a vent system that can hold roofs on.
Jim Jones, principal investigator and associate professor of architecture, says this new vent design, described in the 2004 patent application as a “360 Degree Membrane Roof Pressure Equalizer,” actually creates a suction that makes the roof “stick down.”
Tests were performed on a prototype in the low-speed wind tunnel at Virginia Tech and then a full-scale model of the roof vent was tested at the Langley Full Scale Tunnel at Langley Air Force Base. These tests demonstrated the ability of the vent to generate low pressure that could be used to counter the uplifting forces from high winds.
Virginia Tech alumnus Chuck Johnson, who is president of Acrylife Elastomeric Roofing Inc. of Wytheville, Va., and a co-inventor, says the vent system is inexpensive and easy to install. Two years of research and testing resulted in a wind vent that, when coupled with a single-ply roof cover in a complete roof assembly, will equalize low pressure throughout the entire field of the roof.
Other researchers on the project were Pavlos Vlachos in mechanical engineering, who helped with the design of aerodynamic materials for the prototype, and Elizabeth Grant, a doctoral student in the architecture program, who wrote her masters of science thesis on the project.
“Existing pressure-equalized roof systems use the power of the wind to transmit low pressure to the space immediately beneath the roof membrane, pulling the membrane down to the roof surface,” Grant writes. “The object of this study is the design of a wind vent that, when coupled with a single-ply roof membrane in a complete roof assembly, will successfully equalize low pressure throughout the entire field of the roof. The proposed wind vent differs from existing equalizer valves in its use of the Bernoulli effect to create low pressure. Optimized for ease of manufacturing and installation, the vent is omni-directional and contains no moving parts.”
Leadership lessons from Katrina
Richard Wokutch’s brother and sister-in-law were among the many tourists stranded in New Orleans during Hurricane Katrina. Wokutch, professor and department head of management at Virginia Tech’s Pamplin college of business, says his relatives later managed to flee the city safely, thanks in large part to a determined rescue effort mounted by their hotel’s corporate offices.
Executives at the Toronto, Canada, headquarters of Fairmont Hotels and Resorts assembled a rescue team in Dallas to evacuate the hotel’s 350 or so remaining guests and employees and their families. The team, comprising 10 former Navy SEALs and several managers, accompanied the convoy the company dispatched to the beleaguered city: six buses, a Hummer, and a bulletproof SUV, as well as float craft, and global satellite phones.
Wokutch’s brother was, on the whole, extremely impressed, “as was I,” says Wokutch, who had contacted the company to find out what was being done to assist his relatives and other hotel guests. A Sept. 2 release from the company noted that “all guests, staff, and their family members who remained at the Fairmont New Orleans have been safely evacuated.”
Katrina’s chaotic and tragic aftermath has yielded case studies for researchers and scholars from diverse disciplines and approaches, including civil engineering, meteorology, environmental studies, urban planning, sociology, and political science.
For Wokutch, whose research specialty is international business ethics and the global management of corporate social performance, the evacuation project of the New Orleans Fairmont has served as a positive example of corporate social responsibility during a catastrophe.
The looting of stores by many of the city’s residents and the abandonment of their jobs by a large number of its police officers provided compelling topics for discussion in a continuing education class on ethics and leadership that Wokutch taught on campus last fall for law enforcement officers from across Virginia.
Suzanne Murrmann, a professor of hospitality and tourism management, says researchers have explored the impact of terrorism and political turmoil on tourism businesses — threats which, like natural disasters, often inflict great personal and property losses — and observed that businesses first deal with the situation and care for the people affected. Murrmann, who surveyed restaurant owners and managers in New York City following the terrorist attacks of Sept. 11 and published a co-authored article in the Journal of Travel and Tourism Marketing, says her research revealed an “extraordinary sense of community and desire to help others.” She and Wokutch plan to conduct a similar study focusing on the experiences of hotels in New Orleans during Katrina and its aftermath.
Wokutch and other management scholars agree that the government’s responses to Katrina were characterized by a “crisis of leadership” even as they acknowledge that the magnitude of the problems facing federal, state, and local officials in New Orleans was many times greater than the challenges faced by hotels and other businesses that managed to assist their customers and employees in a timely and effective manner.
Chris Neck, an associate professor of management who teaches a course on management theory and leadership practice, says research suggests that key steps to effective crisis management include “appointing a crisis management team; discussing, in advance, potential crises and developing appropriate responses; preparing a master plan, with clear delegation of responsibility across the organization; appointing an official spokesperson at every location as the one voice for the organization; and forming an effective public relations team.
“From what I’ve read in the newspapers and seen on TV, there seems to have been poor planning and execution of many, if not all, of these steps above,” says Neck, who attributes the problems to weak leadership.
“When leaders are effective, their subordinates or followers are highly motivated, committed, and high performing; the influence they exert over others helps a group or organization achieve its performance goals,” Neck says. “When leaders are ineffective, there is a good chance that their followers do not perform up to their capabilities, are de-motivated, and are dissatisfied; their influence does not contribute to — and often distracts from — attainment of goals.”
Judging from official responses to Hurricane Rita less than a month later, some lessons in crisis management and leadership seem to have been learned from Katrina.
— Sookhan Ho, Pamplin College of Business