Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Life Sciences

Series

2007

Institution
Keyword
Publication
File Type

Articles 1 - 30 of 515

Full-Text Articles in Physical Sciences and Mathematics

Lake Mead National Recreation Area Sensitive Wildlife Species Monitoring And Analysis: Quarterly Progress Report, Period Ending December 31, 2007, Margaret N. Rees Dec 2007

Lake Mead National Recreation Area Sensitive Wildlife Species Monitoring And Analysis: Quarterly Progress Report, Period Ending December 31, 2007, Margaret N. Rees

Wildlife Monitoring

Project 1. Relict Leopard Frog Monitoring, Management, and Research

  • Fall surveys completed at all natural and translocation sites.
  • Coordination for a potential translocation site on BLM lands in the Gold Butte area ongoing – the aim is that this site will be ready for translocations in 2008.
  • Coordination ongoing for evaluation of a translocation site on BLM lands in the Black Mountains, AZ – the plan is to complete compliance in 2008.
  • Coordination and assistance provided to UNLV research efforts on habitat improvements at Blue Point, Rogers, and Pupfish Refuge springs.
  • Relict Leopard Frog Conservation Team meeting held in December. …


Lake Mead National Recreation Area Vegetation Monitoring And Analysis: Quarterly Progress Report, October 1, 2007 To December 31, 2007, Margaret N. Rees Dec 2007

Lake Mead National Recreation Area Vegetation Monitoring And Analysis: Quarterly Progress Report, October 1, 2007 To December 31, 2007, Margaret N. Rees

Vegetation Monitoring

Executive Summary

  • The Weed Sentry program surveyed more than 750 miles of federal lands in Clark County for invasive, exotic plant species.
  • Weed Sentry also removed more than 600,000 individual invasive plants from federal
    lands. These removals represent pro-active efforts that may have forestalled large
    infestations difficult and costly to eradicate.
  • In response to a request by the manager of the Fish and Wildlife Service Desert National
    Wildlife Refuge, a major effort of surveying springs for plant community composition
    and invasive plants provided unique knowledge services by the Weed Sentry program.
    No such baseline information existed for the Sheep Range. …


Limnological Assistance For The Lake Mead National Recreation Area In Meeting The Challenge Of The Water 2025 Initiative: Quarterly Progress Report, Period Ending: December 31, 2007, Margaret N. Rees Dec 2007

Limnological Assistance For The Lake Mead National Recreation Area In Meeting The Challenge Of The Water 2025 Initiative: Quarterly Progress Report, Period Ending: December 31, 2007, Margaret N. Rees

Limnological Studies

  • The limnologist position has been announced.
  • Project 1: Review of the draft Boulder Basin Adaptive Management Plan is underway.
  • Project 2: Development of a white paper expressing the joint needs of the entities involved in Water 2025 projects is being coordinated.
  • Project 3: A bibliographic reference spreadsheet organizing literature citations related to quagga and zebra mussel research has been completed.
  • Project 4: A comprehensive literature search of Lake Mead limnology is well underway; an Access database has been designed to organize reference citations; and a special collections library at UNLV is being established to house original rare documents and other …


Interagency Science And Research: Quarterly Progress Report, Period Ending December 31, 2007, Margaret N. Rees Dec 2007

Interagency Science And Research: Quarterly Progress Report, Period Ending December 31, 2007, Margaret N. Rees

Interagency Science and Research Strategy

  • Meetings were held with the SNAP Recreation Team and the SNAP Cultural Resources Team to request assistance in the development of the science strategy. Draft versions of interagency goals, subgoals, science questions, and associated tasks were given to each team for review and input.
  • Plans were prepared for the peer review of science proposals submitted for consideration as Conservations Initiatives in SNPLMA Round 9.
  • Proceedings of the natural resources management workshop held on September 13 were completed and sent to the Science & Research Team for review by members.
  • An important focus of the Science and Research Team was the …


U.S.-Korea Cooperative Research: Carbon Monoxide As A Substrate For Microbial Maintenance, Gary M. King Dec 2007

U.S.-Korea Cooperative Research: Carbon Monoxide As A Substrate For Microbial Maintenance, Gary M. King

University of Maine Office of Research Administration: Grant Reports

Bacteria play an important role in the global budget of carbon monoxide (CO). Largely unknown bacterial populations in soils and the water column of aquatic systems oxidize hundreds of teragrams per year, or about 10%-20% of the estimated annual flux to the atmosphere. In spite of their biogeochemical significance, relatively little is known about the identity of CO-oxidizing populations active in situ, their phylogenic and physiological diversity or the importance of CO as substrate for their basic metabolic needs. of CO oxidizers. It is clear that CO at high concentrations (> 1000 ppm) can serve as a sole source of …


Prevention Of Staphylococcus Epidermidis Biofilm Formation Using A Low-Temperature Processed Silver-Doped Phenyltriethoxysilane Sol–Gel Coating, Niall Stobie, Brendan Duffy, Declan Mccormack, John Colreavy, Martha Hidalgo, Patrick Mchale, Steven Hinder Dec 2007

Prevention Of Staphylococcus Epidermidis Biofilm Formation Using A Low-Temperature Processed Silver-Doped Phenyltriethoxysilane Sol–Gel Coating, Niall Stobie, Brendan Duffy, Declan Mccormack, John Colreavy, Martha Hidalgo, Patrick Mchale, Steven Hinder

Articles

Sol–gel coatings which elute bioactive silver ions are presented as a potential solution to the problem of biofilm formation on indwelling surfaces. There is evidence that high-temperature processing of such materials can lead to diffusion of silver away from the coating surface, reducing the amount of available silver. In this study, we report the biofilm inhibition of a Staphylococcus epidermidis biofilm using a low-temperature processed silver-doped phenyltriethoxysilane sol–gel coating. The incorporation of a silver salt into a sol–gel matrix resulted in an initial high release of silver in de-ionised water and physiological buffered saline (PBS), followed by a lower sustained …


Semantic Web For Health Care And Biomedical Informatics, Amit P. Sheth Dec 2007

Semantic Web For Health Care And Biomedical Informatics, Amit P. Sheth

Kno.e.sis Publications

No abstract provided.


Systematic Reviews Of Animal Experiments Demonstrate Poor Human Clinical And Toxicological Utility, Andrew Knight Dec 2007

Systematic Reviews Of Animal Experiments Demonstrate Poor Human Clinical And Toxicological Utility, Andrew Knight

Experimentation Collection

The assumption that animal models are reasonably predictive of human outcomes provides the basis for their widespread use in toxicity testing and in biomedical research aimed at developing cures for human diseases. To investigate the validity of this assumption, the comprehensive Scopus biomedical bibliographic databases were searched for published systematic reviews of the human clinical or toxicological utility of animal experiments. In 20 reviews in which clinical utility was examined, the authors concluded that animal models were either significantly useful in contributing to the development of clinical interventions, or were substantially consistent with clinical outcomes, in only two cases, one …


Towards Tractable Local Closed World Reasoning For The Semantic Web, Matthias Knorr, Jose Julio Alferes, Pascal Hitzler Dec 2007

Towards Tractable Local Closed World Reasoning For The Semantic Web, Matthias Knorr, Jose Julio Alferes, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Recently, the logics of minimal knowledge and negation as failure MKNF [12] was used to introduce hybrid MKNF knowledge bases [14], a powerful formalism for combining open and closed world reasoning for the Semantic Web. We present an extension based on a new three-valued framework including an alternating fixpoint, the well-founded MKNF model. This approach, the well-founded MKNF semantics, derives its name from the very close relation to the corresponding semantics known from logic programming. We show that the well-founded MKNF model is the least model among all (three-valued) MKNF models, thus soundly approximating also the two-valued MKNF models from …


Role Of Group A Streptococcus Htra In The Maturation Of Speb Protease, J. N. Cole, J. A. Aquilina, P. G. Hains, A. Henningham, K. S. Sriprakash, M. G. Caparon, V. Nizet, M. Kotb, S. J. Cordwell, S. P. Djordjevic, Mark J. Walker Dec 2007

Role Of Group A Streptococcus Htra In The Maturation Of Speb Protease, J. N. Cole, J. A. Aquilina, P. G. Hains, A. Henningham, K. S. Sriprakash, M. G. Caparon, V. Nizet, M. Kotb, S. J. Cordwell, S. P. Djordjevic, Mark J. Walker

Faculty of Science - Papers (Archive)

The serine protease HtrA (DegP) of the human pathogen Streptococcus pyogenes (group A Streptococcus; GAS) is localized to the ExPortal secretory microdomain and is reportedly essential for the maturation of cysteine protease SpeB. Here we utilize HSC5 (M5 serotype) and the in-frame isogenic mutant HSC5ΔhtrA to determine whether HtrA contributes to the maturation of other GAS virulence determinants. Mutanolysin cell wall extracts and secreted proteins were arrayed by 2-DE and identified by MALDI-TOF PMF analysis. HSC5ΔhtrA had elevated levels of cell wall-associated M protein, whilst the supernatant had higher concentrations of M protein fragments and a reduced amount of mature …


Changing Cultures Of Water In Eastern Australian Backyard Gardens, Lesley M. Head, Pat Muir Dec 2007

Changing Cultures Of Water In Eastern Australian Backyard Gardens, Lesley M. Head, Pat Muir

Faculty of Science - Papers (Archive)

Research into diverse cultural understandings of water provides important contributions to the pressing global issue of sustainable supply, particularly when combined with analysis of relationships between everyday household practice and larger sociotechnical networks of storage and distribution. Here we analyse semi-structured interviews with 298 people about their 241 backyards in the Australian east coast cities of Sydney and Wollongong, undertaken during the 2002-03 drought. Water emerged as an important issue in both consciousness and practice. In contrast to a number of other environmental issues which stimulate more polarised responses, a commitment to reducing water consumption was shared across the study …


Video On The Semantic Sensor Web, Cory Andrew Henson, Amit P. Sheth, Prateek Jain, Josh Pschorr, Terry Rapoch Dec 2007

Video On The Semantic Sensor Web, Cory Andrew Henson, Amit P. Sheth, Prateek Jain, Josh Pschorr, Terry Rapoch

Kno.e.sis Publications

Millions of sensors around the globe currently collect avalanches of data about our world. The rapid development and deployment of sensor technology is intensifying the existing problem of too much data and not enough knowledge. With a view to alleviating this glut, we propose that sensor data, especially video sensor data, can be annotated with semantic metadata to provide contextual information about videos on the Web. In particular, we present an approach to annotating video sensor data with spatial, temporal, and thematic semantic metadata. This technique builds on current standardization efforts within the W3C and Open Geospatial Consortium (OGC) and …


A General Boosting Method And Its Application To Learning Ranking Functions For Web Search, Zhaohui Zheng, Hongyuan Zha, Tong Zhang, Olivier Chapelle, Keke Chen, Gordon Sun Dec 2007

A General Boosting Method And Its Application To Learning Ranking Functions For Web Search, Zhaohui Zheng, Hongyuan Zha, Tong Zhang, Olivier Chapelle, Keke Chen, Gordon Sun

Kno.e.sis Publications

We present a general boosting method extending functional gradient boosting to optimize complex loss functions that are encountered in many machine learning problems. Our approach is based on optimization of quadratic upper bounds of the loss functions which allows us to present a rigorous convergence analysis of the algorithm. More importantly, this general framework enables us to use a standard regression base learner such as decision trees for fitting any loss function. We illustrate an application of the proposed method in learning ranking functions for Web search by combining both preference data and labeled data for training. We present experimental …


Diffusion Of Collective-Action Innovations Among Pastoralists In Liben District, Ethiopia, D. Layne Coppock, Solomon Desta, Getachew Gebru, Getachew Kassa, Seyoum Tezera Dec 2007

Diffusion Of Collective-Action Innovations Among Pastoralists In Liben District, Ethiopia, D. Layne Coppock, Solomon Desta, Getachew Gebru, Getachew Kassa, Seyoum Tezera

Environment and Society Faculty Publications

In 2001 PARIMA and her partners began to create collective-action groups among illiterate, settled pastoralists in Ethiopia. These groups—soon dominated by women—focused on savings-led microfinance, small business activity, and livestock marketing to increase incomes and diversify livelihoods. Fifty-nine groups with over 2,100 members were formed using intensive training methods, and they have subsequently merged into legally recognized cooperatives. We regard this approach as successful and sustainable. We were curious, however, if “the word has spread” and collective-action has spontaneously arisen beyond our immediate project area. Preliminary findings from recent surveys of settlements in Liben District indicate that diffusion of collective-action …


Building Effective Community Participation And Stakeholder Partnerships To Promote Positive Change In The Southern Ethiopian Rangelands, D. Layne Coppock, Solomon Desta, Getachew Gebru, Seyoum Tezera, Dadi Amosha Dec 2007

Building Effective Community Participation And Stakeholder Partnerships To Promote Positive Change In The Southern Ethiopian Rangelands, D. Layne Coppock, Solomon Desta, Getachew Gebru, Seyoum Tezera, Dadi Amosha

Environment and Society Faculty Publications

Recently there has been increased recognition that authentic community participation and creating strong inter-institutional partnerships are both important in the process of capacity building, generating innovation, and sustaining development achievements in rural Africa. Here we summarize a process of community participation and formation of institutional partnerships in support of pastoral risk-management interventions over the past seven years on the Borana Plateau. Community involvement has been stimulated using Participatory Rural Appraisal (PRA) methods. This has resulted in the proliferation of pastoral collective-action groups that have diversified livelihoods, engaged markets, and improved incomes. Implementing and sustaining positive change, however, has also been …


Can Collective Action And Capacity Building Reduce Vulnerability Among Settled Pastoralists?, D. Layne Coppock, Solomon Desta, Getachew Gebru, Seyoum Tezera Dec 2007

Can Collective Action And Capacity Building Reduce Vulnerability Among Settled Pastoralists?, D. Layne Coppock, Solomon Desta, Getachew Gebru, Seyoum Tezera

Environment and Society Faculty Publications

In 2001 PARIMA and her partners began to create collective-action groups among illiterate, settled pastoralists in southern Ethiopia. These groups—dominated by women—focused on savings-led microfinance, small business, and livestock marketing to increase incomes and diversify livelihoods. Fifty-nine groups with over 2,100 members were formed using intensive capacity- building methods. After six years we wanted to compare group members with their neighbors who never participated in the PARIMA program. We surveyed 180 individuals from groups and paired control (traditional) communities. Respondents were asked to assess the extent that they perceived positive, negative, or no change in their lives over the past …


Stakeholder Alliance Facilitates Re-Introduction Of Prescribed Fire On The Borana Plateau Of Southern Ethiopia, D. Layne Coppock, Getachew Gebru, Solomon Desta, Lemma Gizachew, Dadhi Amosha, Feyissa Taffa Dec 2007

Stakeholder Alliance Facilitates Re-Introduction Of Prescribed Fire On The Borana Plateau Of Southern Ethiopia, D. Layne Coppock, Getachew Gebru, Solomon Desta, Lemma Gizachew, Dadhi Amosha, Feyissa Taffa

Environment and Society Faculty Publications

The implementation of a new prescribed fire program to restore bush-encroached rangelands in southern Ethiopia—and hence increase herbaceous forage supplies for livestock—is given as an example of an integrated action involving multiple institutions to address resource-management problems. The resumption of planned fire—traditionally conducted over hundreds of years by pastoralists until the 1970s—was preceded by key activities including mobilization of the pastoral community, review of government proclamations regarding use of fire, interaction with policy makers, capacity building among pastoralists and agency personnel on how to implement and manage planned fires, development of an overall prescribed burn plan, selection of geo-referenced sites, …


Collective Action Among Agro-Pastoralists In Baringo District, Kenya: Identifying And Nurturing The Entrepreneurs, D. Layne Coppock, Mark N. Mutinda, Stellamaris K. Muthoka, Abdillahi A. Aboud Dec 2007

Collective Action Among Agro-Pastoralists In Baringo District, Kenya: Identifying And Nurturing The Entrepreneurs, D. Layne Coppock, Mark N. Mutinda, Stellamaris K. Muthoka, Abdillahi A. Aboud

Environment and Society Faculty Publications

The rural population of Baringo District in the Rift Valley of north-central Kenya faces numerous challenges including widespread environmental degradation and poverty. The region has endured decades of failed development projects, proliferation of food aid, and has been studied extensively. We have recently undertaken a different approach focused on bottom-up participatory action research and outreach among the Il Chamus and Tugen ethnic communities. The objective is to explore new ways to empower local people via provision of information, novel experiences, and initial access to resources to allow them to envision an alternative future and implement their own activities to better-manage …


The Tropical Forest And Fire Emissions Experiment: Method Evaluation Of Volatile Organic Compound Emissions Measured By Ptr-Ms, Ftir, And Gc From Tropical Biomass Burning, T. G. Karl, Ted J. Christian, Robert J. Yokelson, Paulo Artaxo, Wei Min Hao, Alex Guenther Nov 2007

The Tropical Forest And Fire Emissions Experiment: Method Evaluation Of Volatile Organic Compound Emissions Measured By Ptr-Ms, Ftir, And Gc From Tropical Biomass Burning, T. G. Karl, Ted J. Christian, Robert J. Yokelson, Paulo Artaxo, Wei Min Hao, Alex Guenther

Chemistry and Biochemistry Faculty Publications

Volatile Organic Compound (VOC) emissions from fires in tropical forest fuels were quantified using Proton-Transfer-Reaction Mass Spectrometry (PTRMS), Fourier Transform Infrared Spectroscopy (FTIR) and gas chromatography (GC) coupled to PTRMS (GC-PTR-MS). We investigated VOC emissions from 19 controlled laboratory fires at the USFS (United States Forest Service) Fire Sciences Laboratory and 16 fires during an intensive airborne field campaign during the peak of the burning season in Brazil in 2004. The VOC emissions were dominated by oxygenated VOCs (OVOC) (OVOC/NMHC similar to 4:1, NMHC: non-methane hydrocarbons) The specificity of the PTR-MS instrument, which measures the mass to charge ratio of …


Evaluation Of Striped Bass Stocks In Virginia : Monitoring And Tagging Studies, 2004-2008 - Annual Report 1 September 2006 - 31 August 2007, Philip W. Sadler, John M. Hoenig, Robert E. Harris, Rebecca J. Wilk, Lydia M. Goins Nov 2007

Evaluation Of Striped Bass Stocks In Virginia : Monitoring And Tagging Studies, 2004-2008 - Annual Report 1 September 2006 - 31 August 2007, Philip W. Sadler, John M. Hoenig, Robert E. Harris, Rebecca J. Wilk, Lydia M. Goins

Reports

This report presents the results of striped bass (Morone saxatilis) tagging and monitoring activities in Virginia during the period 1 September 2006 through 31 August 2007. It includes an assessment of the biological characteristics of striped bass taken from the 2007 spring spawning run, estimates of annual survival and fishing mortality based on annual spring tagging, and the preliminary results of the fall 2006 study that documents the prevalence of mycobacterial infections of striped bass in Chesapeake Bay. The information contained in this report is required by the Atlantic States Marine Fisheries Commission and is used to implement a coordinated …


1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Kis(Trifluoro­Meth­Yl)- 1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Hydro­(C60-IH)[5,6]Fullerene, Natalia B. Shustova Prof. Dr., O.P. Anderson, O. V. Boltalina, S. H. Strauss, I. E. Kareev Nov 2007

1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Kis(Trifluoro­Meth­Yl)- 1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Hydro­(C60-IH)[5,6]Fullerene, Natalia B. Shustova Prof. Dr., O.P. Anderson, O. V. Boltalina, S. H. Strauss, I. E. Kareev

Faculty Publications

The title compound, C72F36, is one of four isomers of C60(CF3)12 for which crystal structures have been obtained. The fullerene mol­ecule has an idealized Ih C60 core with the 12 CF3 groups arranged in an asymmetric fashion on two ribbons of edge-sharing C6(CF3)2 hexa­gons, a parametaparaparaparametapara ribbon and a parametapara ribbon, giving an overall pmp 3 mp,pmp structure. There are no cage Csp 3 …


Leveraging Semantic Web Techniques To Gain Situational Awareness, Amit P. Sheth Nov 2007

Leveraging Semantic Web Techniques To Gain Situational Awareness, Amit P. Sheth

Kno.e.sis Publications

No abstract provided.


Assessing Population Level Genetic Instability Via Moving Average, Samuel Mcdaniel, Rebecca Betensky, Tianxi Cai Nov 2007

Assessing Population Level Genetic Instability Via Moving Average, Samuel Mcdaniel, Rebecca Betensky, Tianxi Cai

Harvard University Biostatistics Working Paper Series

No abstract provided.


Biomass And Biofuels In Maine: Estimating Supplies For Expanding The Forest Products Industry, Jonathan Rubin, Kate Dickerson, Jacob Kavkewitz Nov 2007

Biomass And Biofuels In Maine: Estimating Supplies For Expanding The Forest Products Industry, Jonathan Rubin, Kate Dickerson, Jacob Kavkewitz

Energy & the Environment

This paper estimates the renewable energy potential of Maine’s forest resources, and how much energy these resources could potentially provide the state. Using the most recent state-specific data available, and a methodology similar to the Billion Tons Report, we find that ethanol production from Maine’s forest residues could potentially provide 18% of Maine’s transportation (gasoline) fuels with a fermentation wood to ethanol process. Making Fischer-Tropsch diesel (F-T diesel) using forest residues can replace 39% of Maine’s petro-diesel consumption. Actual levels of biofuels that can be produced will depend on conversion factors and forestry residue removals that are subject to uncertainty.


2007 Scholars And Artists Bibliography, Michael Schwartz Library, Cleveland State University, Friends Of The Michael Schwartz Library, Joanne E. Goodell Ph.D. Nov 2007

2007 Scholars And Artists Bibliography, Michael Schwartz Library, Cleveland State University, Friends Of The Michael Schwartz Library, Joanne E. Goodell Ph.D.

Scholars and Artists Bibliographies

This bibliography was created for the annual Friends of the Michael Schwartz Library Scholars and Artists Reception, recognizing scholarly and creative achievements of Cleveland State University faculty, staff and emeriti. Dr. Joanne Goodell was the guest speaker.


Biofuel Feedstocks: The Risk Of Future Invasions, Joseph M. Ditomaso, Jacob N. Barney, Allison M. Fox Nov 2007

Biofuel Feedstocks: The Risk Of Future Invasions, Joseph M. Ditomaso, Jacob N. Barney, Allison M. Fox

All U.S. Government Documents (Utah Regional Depository)

In an effort to decrease greenhouse gas emissions, expand domestic energy production, and maintain economic growth, public and private investments are being used to pursue dedicated feedstock crops for biofuel production. Unlike food crops grown for grain-based ethanol (e.g., corn), which require high inputs of fertilizers and pesticides and typically are grown on prime agricultural land, proposed lignocellulose-based energy crops (e.g., switchgrass) typically have a neutral or negative carbon budget, require relatively few economic or environmental inputs, and can be cultivated on marginal, lower-productivity land. Thus, a rapidly growing industry related to crop selection, cultivar improvement, and conversion technilogies is …


Can Semantic Web Techniques Empower Comprehension And Projection In Cyber Situational Awareness?, Amit P. Sheth Nov 2007

Can Semantic Web Techniques Empower Comprehension And Projection In Cyber Situational Awareness?, Amit P. Sheth

Kno.e.sis Publications

No abstract provided.


Semantic Convergence Of Wikipedia Articles, Christopher J. Thomas, Amit P. Sheth Nov 2007

Semantic Convergence Of Wikipedia Articles, Christopher J. Thomas, Amit P. Sheth

Kno.e.sis Publications

Social networking, distributed problem solving and human computation have gained high visibility. Wikipedia is a well established service that incorporates aspects of these three fields of research. For this reason it is a good object of study for determining quality of solutions in a social setting that is open, completely distributed, bottom up and not peer reviewed by certified experts. In particular, this paper aims at identifying semantic convergence of Wikipedia articles; the notion that the content of an article stays stable regardless of continuing edits. This could lead to an automatic recommendation of good article tags but also add …


Supporting Complex Thematic, Spatial And Temporal Queries Over Semantic Web Data, Matthew Perry, Amit P. Sheth, Farshad Hakimpour, Prateek Jain Nov 2007

Supporting Complex Thematic, Spatial And Temporal Queries Over Semantic Web Data, Matthew Perry, Amit P. Sheth, Farshad Hakimpour, Prateek Jain

Kno.e.sis Publications

Spatial and temporal data are critical components in many applications. This is especially true in analytical domains such as national security and criminal investigation. Often, the analytical process requires uncovering and analyzing complex thematic relationships between disparate people, places and events. Fundamentally new query operators based on the graph structure of Semantic Web data models, such as semantic associations, are proving useful for this purpose. However, these analysis mechanisms are primarily intended for thematic relationships. In this paper, we describe a framework built around the RDF metadata model for analysis of thematic, spatial and temporal relationships between named entities. We …


Conjunctive Queries For A Tractable Fragment Of Owl 1.1, Markus Krotzsch, Sebastian Rudolph, Pascal Hitzler Nov 2007

Conjunctive Queries For A Tractable Fragment Of Owl 1.1, Markus Krotzsch, Sebastian Rudolph, Pascal Hitzler

Computer Science and Engineering Faculty Publications

Despite the success of the Web Ontology Language OWL, the development of expressive means for querying OWL knowledge bases is still an open issue. In this paper, we investigate how a very natural and desirable form of queries-namely conjunctive ones-can be used in conjunction with OWL such that one of the major design criteria of the latter-namely decidability-can be retained. More precisely, we show that querying the tractable fragment EL++ of OWL 1.1 is decidable. We also provide a complexity analysis and show that querying unrestricted EL++ is undecidable.