In a new Washington Times article on Maryland’s minority-contracting program, UMBC political science and public policy professor George La Noue argues that definitional and structural program flaws translate to too few businesses “graduating” from the program (i.e., losing eligibility through successful growth to a certain size).

La Noue argues that the definition of what qualifies a business as “disadvantaged” for program eligibility is too broad. He suggests, “To argue that someone is economically disadvantaged who has that kind of money is a very tortured definition of that concept; it would mean that 95 percent of all Americans are disadvantaged. The economic definition of net worth is way too high and there are also a number of ways to get around it,” such as keeping liquidity in the business or a spouse’s account.

Update: La Noue commented in a second Washington Times article on June 6th that explored the Department of Transportation’s Office of Minority Business Enterprise, Maryland’s certification agency for Minority Business Enterprise (MBE) and Disadvantaged Business Enterprise (DBE) programs. La Noue suggested that the office’s enforcement/regulatory responsibilities conflict with its mission to promote and expand the programs.

Christine Mallinson, associate professor in the Language, Literacy & Culture Program, is co-editor, with Becky Childs and Gerard Van Herk, of the new book, Data Collection in Sociolinguistics: Methods and Applications (Routledge, 2013).

The book website notes, “This edited volume provides up-to-date, succinct, relevant, and informative discussion about methods of data collection in sociolinguistic research. It covers the main areas of research design, conducting research, and sharing data findings with longer chapters and shorter vignettes written by a range of top sociolinguists, both veteran and emerging scholars. Here is the one-stop, go-to guide for the numerous quantitative, qualitative, and mixed methods that are used in sociolinguistic research, ensuring that Data Collection in Sociolinguistics will be not only useful in the classroom but also as a reference tool for active researchers.”

Professor J.K. Chambers of the University of Toronto writes in the foreword to the volume, “This collection provides a balanced, judicious, forward-looking summation of the ways in which we collect, access and process the data that is the foundation of our enterprise. In its format and its tone, it has the feeling of a symposium involving a select group of sociolinguists sharing their personal experiences as well as their collective wisdom. It is an invaluable sourcebook for researchers and students and also for veteran fieldworkers in the diverse situations we face on entering the community.”

Did you know you can create an app using JavaScript? Read these three stories of users who went on to do just that.

1. Jonathan and SimpleTax

Jonathan never wanted to become a programmer, he wanted to learn to solve problems. With Code Year, he got the skills to do that. Now he’s building an app to simplify doing your taxes.

2. Ryan and Sworkit

Last year Ryan was looking for ways to learn to code. After trying books, videos and articles, he stumbled upon Codecademy. Armed with the skills he learned there, Ryan wanted to build something of his own.

3. Michael and GVING

When Michael Perry founded GVING, he knew he would have to learn to code eventually. With Codecademy (and the help of some friends) he finally met his goal.

Did you know you can create an app using JavaScript? Read these three stories of users who went on to do just that.

1. Jonathan and SimpleTax

Jonathan never wanted to become a programmer, he wanted to learn to solve problems. With Code Year, he got the skills to do that. Now he’s building an app to simplify doing your taxes.

2. Ryan and Sworkit

Last year Ryan was looking for ways to learn to code. After trying books, videos and articles, he stumbled upon Codecademy. Armed with the skills he learned there, Ryan wanted to build something of his own.

3. Michael and GVING

When Michael Perry founded GVING, he knew he would have to learn to code eventually. With Codecademy (and the help of some friends) he finally met his goal.

Ph.D. Dissertation Defense

Mid-Infrared Photonic Integration

Dingkai Guo

10:00am Tuesday, 4 June 2013, TRC CASPR conference room

The mid-Infrared (Mid-IR) wavelength range is important for applications including medical and security imaging, environmental trace gas sensing and free space communications. However, photonic integrated circuits (PICs) in the mid-IR range are completely under-developed which significantly slows the reduction of mid-IR system size, weight, and coupling losses and limits the development of highly functional mid-IR photonic modules with lower cost. In this dissertation, a solution to mid-IR photonic integration was demonstrated using a compact widely tunable mid-IR transmitter and a mid-IR amplifying photo-detector, which can be integrated with the mid-IR source.

This integrated widely tunable mid-IR source is fabricated by incorporating super structure grating (SSG) to the mid-IR quantum cascade laser (QCL) waveguide. The emission wavelength of the fabricated SSG-DBR QCL can be well controlled by varying the injection currents to the two grating sections. The wavelength can be tuned from 4.58μm to 4.77μm (90cm-1) with a supermode spacing of 30nm. This SSG-DBR QCL can be a compact replacement for the external cavity QCL used in current mid-IR sensors.

Mid-IR amplification and detection can be achieved using the same material as the mid-IR source. This QCL amplifier has an adjustable bandwidth and tunable gain peak, so it can function as a tunable mid-IR filter. By biasing the QCL just below its threshold, we demonstrated more than 11dB optical gain and over 28dB electrical gain at specified wavelengths. In the electrical gain measurement process, the resonant amplifier also functioned as a detector. This indicates that intersubband-based gain materials are ideal candidates for mid-IR photonic integrations.

Beside the optimized fabrication processes, new characterization technique based on the electrical derivative of the QCL I-V curves is used to quickly acquire the QCL threshold and leakage current, and explore the device carrier transport. The leakage currents present in different QCL waveguide structures are also studied and compared using this technique.

Finally, we report that the telecom wavelengths induced optical quenching effects on mid-IR QCLs when the QCLs are operated well above their threshold. The quenching effect is a result of intersubband bandbending and it depends on the coupled near-IR intensity, wavelength, and the QCL voltage bias. The quenching effects not only can be used for mid-IR QCL optical switching and modulation but also reveal that the mid-IR QCLs can function as “converters” to convert the telecom optical signal into the mid-IR optical signal at the near-IR fiber end.

A coherent mid-IR transceiver with both transmitting and receiving functions can be realized based on each integrated component introduced in this dissertation. This compact transceiver includes an integrated widely tunable mid-IR source, a mid-IR filter, amplifier, and detector based on the same material system.

Committee: Drs. Fow-Sen Choa (Chair), Anthony Johnson, Terrance Worchesky (Physics) , Li Yan, Gymama Slaughter