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UNT College of Engineering
Text-to-text Semantic Similarity for Automatic Short Answer Grading
Date: March 2009
Creator: Mohler, Michael & Mihalcea, Rada
Description: In this paper, the authors explore unsupervised techniques for the task of automatic short answer grading. The authors compare a number of knowledge-based and corpus-based measures of text similarity, evaluate the effect of domain and size on the corpus-based measures, and also introduce a novel technique to improve the performance of the system by integrating automatic feedback from the student answers. Overall, our system significantly and consistently outperforms other unsupervised methods for short answer grading that have been proposed in the past.
Contributing Partner: UNT College of Engineering
Permallink:digital.library.unt.edu/ark:/67531/metadc31017/
TextRank: Bringing Order into Texts
Date: July 2004
Creator: Mihalcea, Rada & Tarau, Paul
Description: In this paper, the authors introduce TextRank, a graph-based ranking model for text processing, and show how this model can be successfully used in natural language applications. In particular, the authors propose two innovative unsupervised methods for keyword and sentence extraction, and show that the results obtained compare favorably with previously published results on established benchmarks.
Contributing Partner: UNT College of Engineering
Permallink:digital.library.unt.edu/ark:/67531/metadc30962/
Throughput Optimization in Multi-Cell CDMA Networks
Date: March 2005
Creator: Akl, Robert G.; Naraghi-Pour, Mort & Hegde, Manju
Description: In this paper, the authors investigate the performance of a multi-cell CDMA network by determining the maximum throughput that the network can archive for a given grade-of-service requirement, quality-of-service requirement, network topology and call arrival rate profile. The analysis is restricted to the reverse link and accounts for mobility of users between cell. A constrained nonlinear optimization problem is formulated that maximizes the network throughput subject to upper bounds on the blocking probabilities and a lower bound on the bit energy to interference ratio. The goal is to optimize the usage of network resources, provide consistent grade-of-service for all the cells in the network, and maintain a pre-specified quality-of-service. The solution to the optimization problem yields the maximum network throughput as well as the maximum number of calls that should be admitted in each cell for a given topology and call arrival rate profile. Our optimization algorithm yields significantly higher throughput compared with traditional call admission schemes.
Contributing Partner: UNT College of Engineering
Permallink:digital.library.unt.edu/ark:/67531/metadc30823/
Throughput Validation of an Advanced Channel Assignment Algorithm in IEEE 802.11 WLAN
Date: February 2009
Creator: Haidar, Mohamad; Al-Rizzo, Hussain M.; Chan, Yupo; Akl, Robert G. & Bouharras, Mohamad
Description: In this article, an enhanced channel-assignment algorithm at the Access Points (APs) of a Wireless Local Area Network (WLAN) is validated. The algorithm aims to maximize the Signal-to-Interference Ratio (SIR) at the user level in order to determine the appropriate channel at the APs. The initial channel assignment step at the APs is based on minimizing the total interference between APs. Based on this initial assignment, the SIR for each user is calculated. Then, another channel assignment is performed based on maximizing the SIR at the users. The algorithm can be applied to any WLAN, irrespective of the user distribution and user load. Results show that the algorithm is capable of significantly increasing the SIR over the WLAN, which in turn should improve throughput. Therefore, the authors use OPNET simulation tool to construct several realistic scenarios in order to validate our results.
Contributing Partner: UNT College of Engineering
Permallink:digital.library.unt.edu/ark:/67531/metadc30850/
Topic Identification Using Wikipedia Graph Centrality
Date: May 2009
Creator: Coursey, Kino High & Mihalcea, Rada
Description: This paper presents a method for automatic topic identification using a graph-centrality algorithm applied to an encyclopedic graph derived from Wikipedia. When tested on a data set with manually assigned topics, the system is found to significantly improve over a simpler baseline that does not make use of the external encyclopedic knowledge.
Contributing Partner: UNT College of Engineering
Permallink:digital.library.unt.edu/ark:/67531/metadc31020/
Toward Communicating Simple Sentences Using Pictorial Representations
Date: April 2009
Creator: Mihalcea, Rada & Leong, Ben
Description: This paper evaluates the hypothesis that pictorial representations can be used to effectively convey simple sentences across language barriers. Comparative evaluations show that a considerable amount of understanding can be achieved using visual descriptions of information, with evaluation figures within a comparable range of those obtained with linguistic representations produced by an automatic machine translation system.
Contributing Partner: UNT College of Engineering
Permallink:digital.library.unt.edu/ark:/67531/metadc31021/
Toward Communicating Simple Sentences Using Pictorial Representations
Date: August 2006
Creator: Mihalcea, Rada & Leong, Ben
Description: This paper evaluates the hypothesis that pictorial representations can be used to effectively convey simple sentences across language barriers. Comparative evaluations show that a considerable amount of understanding can be achieved using visual descriptions of information, with evaluation figures within a comparable range of those obtained with linguistic representations produced by an automatic machine translation system.
Contributing Partner: UNT College of Engineering
Permallink:digital.library.unt.edu/ark:/67531/metadc30986/
Transformational Paradigm for Engineering and Engineering Technology Education
Date: November 2008
Creator: Barbieri, Enrique & Fitzgibbon, William
Description: This paper discusses a transformational paradigm for engineering and engineering technology education. The knowledge explosion in science, technology, engineering & mathematics (STEM) over the past decades is unquestionably overwhelming. It is important that those involved in STEM quickly adapt. Life-long learning has taken a do-or-die slant, as technological breakthroughs turn obsolete within only a few years of their inception. Medical and law degree curricula became more "professional" and require a "pre-degree" status to be considered for admission. However, the traditional engineering degree plan is essentially the same as that of the mid 20th Century. Legislation in some states places additional pressure on baccalaureate degrees by questioning the need for anything above 120 credit hours. The result is (i) fewer engineering-specific courses; (ii) courses that heavily emphasize theory; and (iii) a subsequent reduction in hands-on, laboratory oriented, experimental learning. Engineering Technology curricula are designed to have experiential learning as the educational backbone. This forces a reduction in mathematical and scientific depth that is compensated by a richness of laboratory courses in almost one-to-one proportion to lecture courses, and which emphasize the application of engineering. The main challenges to establish and maintain experiential learning include (i) availability of slots in the curricula ...
Contributing Partner: UNT College of Engineering
Permallink:digital.library.unt.edu/ark:/67531/metadc115194/
UMTS Capacity and Throughput Maximization for Different Spreading Factors
Date: July 2006
Creator: Akl, Robert G. & Nguyen, Son
Description: This article discusses UMTS capacity and throughput maximization for different spreading factors. An analytical model for calculating capacity in multi-cell UMTS networks is presented. Capacity is maximized for different spreading factors and for perfect and imperfect power control. The authors also design and implement a local call admission control (CAC) algorithm which allows for the simulation of network throughput for different spreading factors and various mobility scenarios. The design of the CAC algorithm uses global information ; it incorporates the call arrival rates and the user mobilities across the network and guarantees the users' quality of service as well as pre-specified blocking probabilities. On the other hand, its implementation in each cell uses local information; it only requires the number of calls currently active in that cell. The capacity and network throughput were determined for signal-to-interference threshold from 5 dB to 10 dB and spreading factor values of 256, 64, 16, and 4.
Contributing Partner: UNT College of Engineering
Permallink:digital.library.unt.edu/ark:/67531/metadc30833/
Unsupervised Graph-based Word Sense Disambiguation Using Measures of Word Semantic Similarity
Date: September 2007
Creator: Sinha, Ravi & Mihalcea, Rada
Description: This paper describes an unsupervised graph-based method for word sense disambiguation, and presents comparative evaluations using several measures of word semantic similarity and several algorithms for graph centrality. The results indicate that the right combination of similarity metrics and graph centrality algorithms can lead to a performance competing with the state-of-the-art in unsupervised word sense disambiguation, as measured on standard data sets.
Contributing Partner: UNT College of Engineering
Permallink:digital.library.unt.edu/ark:/67531/metadc30999/