From Structure to Function in Open Ionic Channels

We consider a simple working hypothesis that all permeation properties of open ionic channels can be predicted by understanding electrodiffusion in fixed structures, without invoking conformation changes, or changes in chemical bonds. We know, of course, that ions can bind to specific protein structures, and that this binding is not easily described by the traditional electrostatic equations of physics textbooks, that describe average electric fields, the so-called `mean field'. The question is which specific properties can be explained just by mean field electrostatics and which cannot. I believe the best way to uncover the specific chemical properties of channels is to invoke them as little as possible, seeking to explain with mean field electrostatics first. Then, when phenomena appear that cannot be described that way, by the mean field alone, we turn to chemically specific explanations, seeking the appropriate tools (of electrochemistry, Langevin, or molecular dynamics, for example) to understand them. In this spirit, we turn now to the structure of open ionic channels, apply the laws of electrodiffusion to them, and see how many of their properties we can predict just that way.Comment: Nearly final version of publicatio

Active FPGA Security through Decoy Circuits

Field Programmable Gate Arrays (FPGAs) based on Static Random Access Memory (SRAM) are vulnerable to tampering attacks such as readback and cloning attacks. Such attacks enable the reverse engineering of the design programmed into an FPGA. To counter such attacks, measures that protect the design with low performance penalties should be employed. This research proposes a method which employs the addition of active decoy circuits to protect SRAM FPGAs from reverse engineering. The effects of the protection method on security, execution time, power consumption, and FPGA resource usage are quantified. The method significantly increases the security of the design with only minor increases in execution time, power consumption, and resource usage. For the circuits used to characterize the method, security increased to more than one million times the original values, while execution time increased to at most 1.2 times, dynamic power consumption increased to at most two times, and look-up table usage increased to at most seven times the original values. These are reasonable penalties given the size and security of the modified circuits. The proposed design protection method also extends to FPGAs based on other technologies and to Application-Specific Integrated Circuits (ASICs). In addition to the design methodology proposed, a new classification of tampering attacks and countermeasures is presented

Faculty Publications and Creative Works 1999

One of the ways in which we recognize our faculty at the University of New Mexico is through Faculty Publications & Creative Works. An annual publication, it highlights our faculty\u27s scholarly and creative activities and achievements and serves as a compendium of UNM faculty efforts during the 1999 calendar year. Faculty Publications & Creative Works strives to illustrate the depth and breadth of research activities performed throughout our University\u27s laboratories, studios and classrooms. We believe that the communication of individual research is a significant method of sharing concepts and thoughts and ultimately inspiring the birth of new ideas. In support of this, UNM faculty during 1999 produced over 2,292 works, including 1,837 scholarly papers and articles, 78 books, 82 book chapters, 175 reviews, 113 creative works and 7 patented works. We are proud of the accomplishments of our faculty which are in part reflected in this book, which illustrates the diversity of intellectual pursuits in support of research and education at the University of New Mexico