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Spatial data, ranging from various land information data to different types of environmental data, are typically collected and used by different custodians. The full benefits of using spatial data can be achieved by combining the data from different sources covering a common region. Due to organizational, political and technical reasons, it is unrealistic to physically integrate the vast amount of spatial data managed by different systems in different organizations. A practical approach is to provide interoperability to support multi-site data queries. In this paper, we study the performance aspect of complex spatial query processing. We propose a framework for processing queries with multiple spatial and aspatial predicates using data from multiple sites. Using a new concept called generalized filter, a query is processed in thr...
Search engines retrieve and rank Web pages which are not only relevant to a query but also important or popular for the users. This popularity has been studied by analysis of the links between Web resources. Link-based page ranking models such as PageRank and HITS assign a global weight to each page regardless of its location. This popularity measurement has shown successful on general search engines. However unlike general search engines, location-based search engines should retrieve and rank higher the pages which are more popular locally. The best results for a location-based query are those which are not only relevant to the topic but also popular with or cited by local users. Current ranking models are often less effective for these queries since they are unable to estimate the local popularity. We offer a model for calculat...
The inability of the yeast Saccharomyces cerevisiae to ferment xylose effectively under anaerobic conditions is a major barrier to economical production of lignocellulosic biofuels. Although genetic approaches have enabled engineering of S. cerevisiae to convert xylose efficiently into ethanol in defined lab medium, few strains are able to ferment xylose from lignocellulosic hydrolysates in the absence of oxygen. This limited xylose conversion is believed to result from small molecules generated during biomass pretreatment and hydrolysis, which induce cellular stress and impair metabolism. Here, we describe the development of a xylose-fermenting S. cerevisiae strain with tolerance to a range of pretreated and hydrolyzed lignocellulose, including Ammonia Fiber Expansion (AFEX)-pretreated corn stover hydrolysate (ACSH). We genetica...
In many real-world decision making settings, situations arise in which the parties (or: players) involved must collectively make decisions while not every player is supposed to have an equal amount of influence in the outcome of such a decision. The "weighted voting game" is a model that is often used to make such decisions. The amount of influence that a player has in a weighted voting game can be measured by means of various power indices. Weighted voting games are part of the more general class of simple games. In this thesis, we study the problem of finding for a given class of simple games (including weighted voting games), the game in which the distribution of the influence among the players is as close as possible to a given target value (i.e. power index). We investigate the posibilities that we have for exactly solving this ...
BitTorrent has turned into the most popular P2P file sharing protocol and is used for various purposes such as Video on demand and Media Streaming. The fundamental problem with P2P networks in general is that quality of service highly depends on altruistic resource sharing by participating peers. Many peers freeride on the good intentions of others and BitTorrent is no exception. Current solutions like reputation systems and sharing ratio enforcement are complex, exploitable, inaccurate or unfair at times. The need to design scalable mechanisms that mitigate such problems is evident. We demonstrate through measurements that BitTorrent peers are able to barter pieces of different files (indirect interaction) which is a previously unknown property of the BitTorrent protocol. We introduce a centralized extension for the BitTorrent protoc...
E-Commerce has been much more popular in western countries where the development of E-Commerce systems has been relatively matured. While the technology and social credit environment are well developed, E-Commerce is relatively new and receives less acceptance within commercial industries in China. Building trust has been identified as one of the major concerns in E-Commerce. In this paper, we will develop an computational model, which may be used to improve the trust-building relationship among consumers, retailers and authorities. This model considers a number of factors including direct experiences, customer recommendations, and authority certification, while parties involved in the E-Commerce activities can confidently establish and reliably enhance the trustworthiness. We also conduct a case study on how to improve consumer-re...
At present, the worldâs transportation sector is being principally supplied by fossil fuels. However, energy consumption in this sector is drastically increasing and there are concerns with supply, cost, and environmental issues with the continuing use of fossil fuels. Utilizing non-petroleum ethanol in the transportation sector reduces the dependence on oil, and allows for cleaner burning of gasoline.

Lignocellulose materials are structurally composed of five types of polymeric sugars, glucan, galactan, mannan, arabinan, and xylan. NREL has developed a quantitative saccharification (QS) method for determining carbohydrate composition. We proposed a new protocol based on the NREL 2006 Laboratory Analytical Procedure âDetermination of Structural Carbohydrates and Lignin in Biomassâ (Sluiter et al. 2006a) with a slight modification, ...

The production of second generation biofuels -- cellulosic ethanol from renewable lignocellulosic biomass has the potential to lead the bioindustrial revolution necessary to the transition from a fossil fuel-based economy to a sustainable carbohydrate economy. Effective release of fermentable sugars through biomass pretreatment followed by enzymatic hydrolysis is among the most costly steps for emerging cellulosic ethanol biorefineries. In this project, two pretreatment methods (dilute acid, DA, and cellulose solvent- and organic solvent-lignocellulose fractionation, COSLIF) for corn stover were compared. It was found that glucan digestibility of the corn stover pretreated by COSLIF was much higher, along with faster hydrolysis rate, than that by DA- pretreated. This difference was more significant at a low enzyme loading. Quantitative...
In previous years we have been involved in several projects in which users (or visitors) had to find their way in information-rich virtual environments. 'Information-rich' means that the users do not know beforehand what is available in the environment, where to go in the environment to find the information and, moreover, users or visitors do not necessarily know exactly what they are looking for. Information-rich means also that the information may change during time. A second visit to the same environment will require different behavior of the visitor in order for him or her to obtain similar information than was available during a previous visit. In this paper we report about two projects and discuss our attempts to generalize from the different approaches and application domains to obtain a library of methods and tools to design an...
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