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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Exploring Data Driven Models of Transit Travel Time and Delay

Sidhu, Bobjot Singh 01 June 2016 (has links) (PDF)
Transit travel time and operating speed influence service attractiveness, operating cost, system efficiency and sustainability. The Tri-County Metropolitan Transportation District of Oregon (TriMet) provides public transportation service in the tri-county Portland metropolitan area. TriMet was one of the first transit agencies to implement a Bus Dispatch System (BDS) as a part of its overall service control and management system. TriMet has had the foresight to fully archive the BDS automatic vehicle location and automatic passenger count data for all bus trips at the stop level since 1997. More recently, the BDS system was upgraded to provide stop-level data plus 5-second resolution bus positions between stops. Rather than relying on prediction tools to determine bus trajectories (including stops and delays) between stops, the higher resolution data presents actual bus positions along each trip. Bus travel speeds and intersection signal/queuing delays may be determined using this newer information. This thesis examines the potential applications of higher resolution transit operations data for a bus route in Portland, Oregon, TriMet Route 14. BDS and 5-second resolution data from all trips during the month of October 2014 are used to determine the impacts and evaluate candidate trip time models. Comparisons are drawn between models and some conclusions are drawn regarding the utility of the higher resolution transit data. In previous research inter-stop models were developed based on the use of average or maximum speed between stops. We know that this does not represent realistic conditions of stopping at a signal/crosswalk or traffic congestion along the link. A new inter-stop trip time model is developed using the 5-second resolution data to determine the number of signals encountered by the bus along the route. The variability in inter-stop time is likely due to the effect of the delay superimposed by signals encountered. This newly developed model resulted in statistically significant results. This type of information is important to transit agencies looking to improve bus running times and reliability. These results, the benefits of archiving higher resolution data to understand bus movement between stops, and future research opportunities are also discussed.
2

The feasibility of transferring cells from archived buccal swabs to FTA card for long term and simple storage of forensic samples

Khoory, Haifa January 2008 (has links)
[Truncated abstract] The collection of buccal cells is common practise in the epidemiological and forensic science. Unlike venipuncture collection of blood; it is a safer, non-invasive method for collection of biological material. The methods by which these cells are collected from the inner cheek of an individual and stored are the key elements in preserving DNA. Typically, forensic samples require long term storage. Samples are commonly collected on cotton swabs and stored moist at low to ultra-low temperatures (less than -20oC). Although this is the method of choice in most forensic facilities, there are drawbacks. The samples are inherently contaminated with microflora within the oral cavity and the moisture allows a plethora of microorganisms to grow. As the time frame that has elapsed from collection to storage increases, there is an exponential increase in bacterial cells. Storage of containers containing swabs coated with cells at temperatures below 20oC is also costly due to requirements for large freezers which are running and monitored over 24 hours. In the pass 10 to 15 years, researchers have focussed on alternative ways to store buccal cells. The FTA card system by Whatman is one such development. The FTA card is unique in that it provides a means for the collection of buccal cells for storage at room temperature. DNA profiling from samples stored in this way for 11 years has been successfully achieved. The filter paper matrix of the FTA card binds and subsequently lyses cells. ... (2) The second component of this thesis describes a study which subjected cells on buccal swabs to various conditions of increased temperature over periods of time to establish if DNA could be amplified. The aim was to mimic exposure to the vigours of field conditions, particularly in the extreme local environments that prevail in the United Arab Emirates. a. Initially, buccal cells stored at -20oC over 360 days were used to mimic standard archiving procedures. The cells were subsequently transferred to FTA cards, amplified and profiled by using ABI AmpFLSTR Identifiler PCR Amplification Kit (Applied Biosystems, Foster City, CA). Complete STR profiles were successfully recovered from the archived swabs. In most cases 100% of alleles were recovered, suggesting that it is feasible to transfer DNA from properly archived buccal swabs to FTA cards. b. The second phase involved the storage of fresh swabs that had been artificially aged by using incubation temperatures ranging from 40oC to 100oC. Partial profiles resulted from artificially aged samples, indicating that the prevailing conditions prior to low temperature storage of the swabs plays an important role in ensuring cellular integrity and thus, DNA quality. Results from this study suggest that it is possible for biological samples stored under correct conditions to be transferred from swabs to FTA card. In combination, the two chapters presented in this study show that it is feasible to transfer achieved forensic biology samples from swabs to the FTA card system. However, it is necessary to ensure that the samples are treated in the correct manner so as to minimise contamination from external sources and to maintain the correct environmental state to maintain intact cells and usable DNA.
3

Building Evaluation Capacity in Schools

Maras, Melissa Ann 15 July 2008 (has links)
No description available.
4

Scalable Preservation, Reconstruction, and Querying of Databases in terms of Semantic Web Representations

Stefanova, Silvia January 2013 (has links)
This Thesis addresses how Semantic Web representations, in particular RDF, can enable flexible and scalable preservation, recreation, and querying of databases. An approach has been developed for selective scalable long-term archival of relational databases (RDBs) as RDF, implemented in the SAQ (Semantic Archive and Query) system. The archival of user-specified parts of an RDB is specified using an extension of SPARQL, A-SPARQL. SAQ automatically generates an RDF view of the RDB, the RD-view. The result of an archival query is RDF triples stored in: i) a data archive file containing the preserved RDB content, and ii) a schema archive file containing sufficient meta-data to reconstruct the archived database. To achieve scalable data preservation and recreation, SAQ uses special query rewriting optimizations for the archival queries. It was experimentally shown that they improve query execution and archival time compared with naïve processing. The performance of SAQ was compared with that of other systems supporting SPARQL queries to views of existing RDBs. When an archived RDB is to be recreated, the reloader module of SAQ first reads the schema archive file and executes a schema reconstruction algorithm to automatically construct the RDB schema. The thus created RDB is populated by reading the data archive and converting the read data into relational attribute values. For scalable recreation of RDF archived data we have developed the Triple Bulk Load (TBL) approach where the relational data is reconstructed by using the bulk load facility of the RDBMS. Our experiments show that the TBL approach is substantially faster than the naïve Insert Attribute Value (IAV) approach, despite the added sorting and post-processing. To view and query semi-structured Topic Maps data as RDF the prototype system TM-Viewer was implemented. A declarative RDF view of Topic Maps, the TM-view, is automatically generated by the TM-viewer using a developed conceptual schema for the Topic Maps data model. To achieve efficient query processing of SPARQL queries to the TM-view query rewrite transformations were developed and evaluated. It was shown that they significantly improve the query execution time. / eSSENCE

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