Crichigno J.,Northern New Mexico College |
Wu M.Y.,Shanghai JiaoTong University |
Jayaweera S.,University of New Mexico |
Shu W.,University of New Mexico
IEEE Transactions on Parallel and Distributed Systems | Year: 2011
Recent advances in the physical layer have enabled the simultaneous reception of multiple packets by a node in wireless networks. We address the throughput optimization problem in wireless networks that support multipacket reception (MPR) capability. The problem is modeled as a joint routing and scheduling problem, which is known to be NP-hard. The scheduling subproblem deals with finding the optimal schedulable sets, which are defined as subsets of links that can be scheduled or activated simultaneously. We demonstrate that any solution of the scheduling subproblem can be built with |E| + 1 or fewer schedulable sets, where |E| is the number of links of the network. This result is in contrast with previous works that stated that a solution of the scheduling subproblem is composed of an exponential number of schedulable sets. Due to the hardness of the problem, we propose a polynomial time scheme based on a combination of linear programming and approximation algorithm paradigms. We illustrate the use of the scheme to study the impact of design parameters on the performance of MPR-capable networks, including the number of transmit interfaces, the beamwidth, and the receiver range of the antennas. © 2011 IEEE.
Kolb T.,Northern Arizona University |
Dore S.,University of California at Berkeley |
Montes-Helu M.,Northern New Mexico College
Environmental Research Letters | Year: 2013
We assessed the impacts of extreme late-summer drought on carbon balance in a semi-arid forest region in Arizona. To understand drought impacts over extremes of forest cover, we measured net ecosystem production (NEP), gross primary production (GPP), and total ecosystem respiration (TER) with eddy covariance over five years (2006-10) at an undisturbed ponderosa pine (Pinus ponderosa) forest and at a former forest converted to grassland by intense burning. Drought shifted annual NEP from a weak source of carbon to the atmosphere to a neutral carbon balance at the burned site and from a carbon sink to neutral at the undisturbed site. Carbon fluxes were particularly sensitive to drought in August. Drought shifted August NEP at the undisturbed site from sink to source because the reduction of GPP (70%) exceeded the reduction of TER (35%). At the burned site drought shifted August NEP from weak source to neutral because the reduction of TER (40%) exceeded the reduction of GPP (20%). These results show that the lack of forest recovery after burning and the exposure of undisturbed forests to late-summer drought reduce carbon sink strength and illustrate the high vulnerability of forest carbon sink strength in the southwest US to predicted increases in intense burning and precipitation variability. © 2013 IOP Publishing Ltd.
Crichigno J.,Northern New Mexico College |
Ghani N.,University of South Florida
2015 38th International Conference on Telecommunications and Signal Processing, TSP 2015 | Year: 2015
Intrusion Prevention System (IPS) sensors represent the initial security barrier of a network. A main challenge in today's Internet environment is the amount of traffic these devices have to inspect. This paper presents a linear program for traffic scheduling in multi-sensor environments that alleviates inspection load at sensors. The model uses a per-flow alarm rate metric which quantifies the ratio of the amount of traffic that matches the configured signatures to the amount of traffic inspected. Traffic flows can be classified based on the metric, which permits the efficient use of computational resources to inspect suspicious traffic. Numerical results demonstrate how the proposed model can be used in enterprise networks. While the linear program is not constrained to integral solutions, traffic flows are mostly scheduled for inspection to a single sensor, which facilitates the collection of state information. This feature is essential to detect malicious traffic characterized by composite signatures. © 2015 IEEE.
Agency: NSF | Branch: Standard Grant | Program: | Phase: ROBERT NOYCE SCHOLARSHIP PGM | Award Amount: 1.15M | Year: 2010
Four cohorts each consisting of four undergraduate STEM majors are being offered annual scholarships of $12,000 for up to three years to complete the STEM baccalaureate degree and receive secondary teacher certification. Five cohorts of three individuals already possessing a STEM degree are receiving one year scholarships of $10,000 each to gain teaching certification via the Alternate Licensure program. Over the five year project period a total of 77 one year scholarships are being awarded to 31 individuals. Each year five summer internships are available to lower division undergraduates to actively participate in the organization, planning and implementation of informal science outreach activities with the aim of attracting these students into a teaching career.
Currently the institution produces about 8 science teachers a year through the regular teacher education program and about 4 science teachers a year through the alternative licensure program. This project is having a broad impact on the number of science teachers produced who are able to teach primarily in the rural areas of New Mexico. These teachers provide high quality science education to at least 500 students annually and infuse the cadre of STEM teachers with highly trained individuals grounded in both content and pedagogical knowledge who provide junior high and high school students the opportunity to participate in inquiry-based, experiential learning.
Agency: NSF | Branch: Standard Grant | Program: | Phase: Campus Cyberinfrastrc (CC-NIE) | Award Amount: 350.00K | Year: 2015
Northern New Mexico College (Northern) is establishing a dedicated research network fabric and Science DMZ that is: 1) connecting multiple teaching and research laboratories serving biology, chemistry, environmental science, and engineering; and 2) improving the capacity and efficiency of moving Terabytes (TBs) of data sets.
The proposed network upgrades are permitting faculty and students to engage in high-throughput data analysis research. High-speed switches are allowing TBs of data transfers from storage nodes to multiple labs, including solar energy variables needed to analyze irradiance and solar power generation patterns; data sets of 3-D convection simulation computed by Northerns Aguila parallel Supercomputer; and TBs of ribonucleic acid (RNA) sequencing needed to understand the role of Cajal Bodies in the biogenesis of non-coding RNA in land plants.
Northern serves a 72% Hispanic and 11% Native American student population. Northern?s recent development of Engineering, Biology, and Environmental Science programs has greatly increased access to four-year STEM degrees for northern New Mexicans. This CC*DNI project represents the next step in closing the STEM education gap that prevents Hispanics, the fastest growing ethnic group in the nations labor force, and Native Americans from entering STEM professions. The remote experimental control features to lab equipment are also addressing the geographic challenge of campus access for students living in remote mountain villages, especially during winter months, and is allowing for the development of remote undergraduate research experiences known to support the success of minority populations studying STEM.