Geoffrey C. Orsak

Modulation classification in unknown dispersive environments

The problem of distinguishing reliably between signaling formats in the presence of noise, interference, unknown dispersive channel conditions, as well as timing and frequency mismatches is addressed. Methods based on a combination of blind equalization and universal classification are presented and their performance is assessed through simulations.

DSP in high schools: New technologies from the infinity project

The Infinity Project is a joint effort between university educators, high school teachers, administrators, and industrial leaders to establish an engineering curriculum that is taught within the regular high school day. The curriculum teaches students about the design of technology-driven systems and motivates them to learn fundamental concepts of mathematics, science, and engineering. The curriculum currently consists of (1) a course text [1], (2) integrated laboratory exercises with real-time signal processing hardware, (3) summer teacher training institutes, and (4) a web community portal for information sharing (www.infinity-project.org). In this paper, we briefly describe three real-time signal processing laboratory exercises—SketchWave, Coin Counter, and Video Steganography—that are used within the course to both teach and excite students about engineering design, fundamental scientific and mathematical concepts, and the power of problem solving. These representative exercises are drawn from over 200 laboratory worksheets developed for the course and available online for participating schools.

Code-length-based universal extraction for blind signal separation

We propose a blind signal separation algorithm (CLUE) that uses the sum of the individual code lengths of the extracted signals as a measure of the separation performance. The new technique combines a widely-available universal data compression routine with any single-parameter search procedure. Unlike previous approaches, the proposed method is model-free and does not rely on the moment values of the signals for its separation performance. An example shows the algorithms efficiency in separating mixtures of image, audio, and text data.

A distance learning laboratory design experiment in undergraduate digital signal processing

Competitive pressures in the global marketplace have forced companies to form teams from the best talent available irrespective of their geographical location. As it comes online, the National information Infrastructure will be increasingly used to support such interactions. American companies are far ahead of the universities in realizing systems to support such geographically distributed interactions. Universities must catch up by exposing their students to such design environments. In addition, universities should help define and evaluate network-based information dissemination systems by serving as testbeds for new interactive strategies. The paper presents initial results in a distance teaming experiment at the University of Colorado, George Mason University, and Rice University.

Distance teaming experiments in undergraduate DSP

This paper describes the ongoing efforts of the participants of the Signal Processing Education consortium (SPEC) in bringing the most up-to-date technologies to the teaching of undergraduate digital signal processing. In particular, we describe herein the use of new multimedia technologies for distributed teaming of undergraduates and faculty to both take advantage of the diverse faculty expertise and to mimic the increasingly common practice of distributed teaming in industry.

Reflections on a distance education experiment in DSP

Distance education is becoming an increasingly important means of reaching a wider variety of traditional and non-traditional students and of developing unique educational partnerships between universities. In an effort to assist engineering departments just beginning to pursue distance education, the authors reflect on an innovative four year experiment in Internet based distance education involving students and faculty from the University of Colorado at Boulder, George Mason University, Rice University, Cornell University, and Sandia National Labs. The educational and research benefits to both the students and faculty are discussed in detail. In addition, the weaknesses and limitations of this experiment are also addressed. It is hoped that these comments and observations will benefit other institutions beginning to pursue similar distance education programs.

Blind estimation of channel BERs in a multi-receiver network

In wireless communications, it is often desirable to merge bit decisions from multiple receivers to improve overall link performance. It is well known that in order to fuse bit decisions optimally from a network of receivers, precise knowledge of receiver bit error rates (BERs) is needed. This information, however, is rarely available in practice. We present an iterative procedure for blindly estimating receiver BERs to enable near optimal blind fusion of bit decisions in a multi-receiver network. We show that the solution of the estimation problem is a structured eigenvalue task and propose a modified power method procedure to perform it. We prove that the desired solution is a stable point of the algorithm and the algorithm is locally stable. Furthermore, we show, via simulations, that the technique results in excellent performance in nearly all practical operating scenarios.

The INFINITY Project: expanding signal-processing-based engineering education to the high school classroom

This paper outlines the goals, structure, and technology elements of the INFINITY Project, a joint effort between university educators, industrial partners, and civic leaders to introduce a signal-processing-based engineering curriculum at the high school educational level. Implementation issues of the program are addressed, including class textbook and laboratory creation, teacher training, and online classroom support. Initial responses to the effort from teachers and students at fourteen different high schools are highly positive, and plans for further expansion of the program are given.

Designing Pre-College Engineering Curricula and Technology: Lessons Learned From the Infinity Project

The importance of mathematics and science education in todays modern, technology-driven society cannot be understated. This paper describes the history of and ongoing efforts in curricular and educational technology development for the infinity project, a joint effort between educators, administrators, and industry leaders to establish an engineering curriculum at the high school level. Several issues are considered, including the choice and design of the technology platform used in the curriculum, the curricular and technology development timeline, and the design examples chosen to illuminate important engineering concepts within the curriculum. We also provide a list of key best practices and challenges in developing novel pre-college engineering curricula for future engineers.

Asymptotically optimal blind fusion of bit estimates

In wireless communications, merging data from various distributed receivers is a common strategy adopted to improve overall link performance. In this paper, we address the problem of optimally merging bit decisions from various distributed receivers when no information about the channels or about the performance of the receivers is available. Herein, we derive a novel algorithm to blindly form the maximum likelihood estimates (MLEs) of the individual bit error rate (BER) of each of the distributed receivers. We show that the variance in the estimates decays at the same rate (upto a constant) that would be achieved with perfect knowledge of the transmitted bits. Subsequently, we use these estimates to optimally fuse the individual bit decisions, thereby improving overall performance. We show that the above fusion algorithm asymptotically achieves the performance of the globally optimal fusion rule. Also, simulation results show that in all practical operating regimes, this empirical fusion rule outperforms the standard “majority fusion rule” receiver and also the best (minimum BER) receiver in the bank.