897 resultados para information bottleneck method


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Noncompetitive bids have recently become a major concern in both public and private sector construction contract auctions. Consequently, several models have been developed to help identify bidders potentially involved in collusive practices. However, most of these models require complex calculations and extensive information that is difficult to obtain. The aim of this paper is to utilize recent developments for detecting abnormal bids in capped auctions (auctions with an upper bid limit set by the auctioner) and extend them to the more conventional uncapped auctions (where no such limits are set). To accomplish this, a new method is developed for estimating the values of bid distribution supports by using the solution to what has become known as the German Tank problem. The model is then demonstrated and tested on a sample of real construction bid data, and shown to detect cover bids with high accuracy. This paper contributes to an improved understanding of abnormal bid behavior as an aid to detecting and monitoring potential collusive bid practices.

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In numerical weather prediction, parameterisations are used to simulate missing physics in the model. These can be due to a lack of scientific understanding or a lack of computing power available to address all the known physical processes. Parameterisations are sources of large uncertainty in a model as parameter values used in these parameterisations cannot be measured directly and hence are often not well known; and the parameterisations themselves are also approximations of the processes present in the true atmosphere. Whilst there are many efficient and effective methods for combined state/parameter estimation in data assimilation (DA), such as state augmentation, these are not effective at estimating the structure of parameterisations. A new method of parameterisation estimation is proposed that uses sequential DA methods to estimate errors in the numerical models at each space-time point for each model equation. These errors are then fitted to pre-determined functional forms of missing physics or parameterisations that are based upon prior information. We applied the method to a one-dimensional advection model with additive model error, and it is shown that the method can accurately estimate parameterisations, with consistent error estimates. Furthermore, it is shown how the method depends on the quality of the DA results. The results indicate that this new method is a powerful tool in systematic model improvement.

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Astronomy has evolved almost exclusively by the use of spectroscopic and imaging techniques, operated separately. With the development of modern technologies, it is possible to obtain data cubes in which one combines both techniques simultaneously, producing images with spectral resolution. To extract information from them can be quite complex, and hence the development of new methods of data analysis is desirable. We present a method of analysis of data cube (data from single field observations, containing two spatial and one spectral dimension) that uses Principal Component Analysis (PCA) to express the data in the form of reduced dimensionality, facilitating efficient information extraction from very large data sets. PCA transforms the system of correlated coordinates into a system of uncorrelated coordinates ordered by principal components of decreasing variance. The new coordinates are referred to as eigenvectors, and the projections of the data on to these coordinates produce images we will call tomograms. The association of the tomograms (images) to eigenvectors (spectra) is important for the interpretation of both. The eigenvectors are mutually orthogonal, and this information is fundamental for their handling and interpretation. When the data cube shows objects that present uncorrelated physical phenomena, the eigenvector`s orthogonality may be instrumental in separating and identifying them. By handling eigenvectors and tomograms, one can enhance features, extract noise, compress data, extract spectra, etc. We applied the method, for illustration purpose only, to the central region of the low ionization nuclear emission region (LINER) galaxy NGC 4736, and demonstrate that it has a type 1 active nucleus, not known before. Furthermore, we show that it is displaced from the centre of its stellar bulge.

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The South American fur seal, Arctocephalus australis, was one of the earliest otariid seals to be exploited by humans: at least 6000 years ago on the Atlantic coast and 4000 on the Pacific coast of South America. More than 750,000 fur seals were killed in Uruguay until 1991. However, a climatological phenomenon-the severe 1997-1998 El Nino Southern Oscillation (ENSO)-was responsible for the decline of 72% Of the Peruvian fur seal population due to starvation as a consequence of warming of sea-surface temperatures and primary productivity reduction. Currently, there is no precise information on global population size or on the species` conservation status. The present study includes the first bottleneck test for the Pacific and Atlantic populations of A. australis based on the analysis of seven microsatellite loci. Genetic bottleneck compromises the evolutionary potential of a population to respond to environmental changes. The perspective becomes even more alarming due to current global warming models that predict stronger and more frequent ENSO events in the future. Our analysis found moderate support for deviation from neutrality-equilibrium for the Pacific population of fur seals and none for the Atlantic population. This difference among population reflects different demographic histories, and is consistent with a greater reduction in population size in the Pacific. Such an event could be a result of the synergic effects of recurrent ENSO events and the anthropogenic impact (sealing and prey overfishing) on this population.

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NMR quantum information processing studies rely on the reconstruction of the density matrix representing the so-called pseudo-pure states (PPS). An initially pure part of a PPS state undergoes unitary and non-unitary (relaxation) transformations during a computation process, causing a ""loss of purity"" until the equilibrium is reached. Besides, upon relaxation, the nuclear polarization varies in time, a fact which must be taken into account when comparing density matrices at different instants. Attempting to use time-fixed normalization procedures when relaxation is present, leads to various anomalies on matrices populations. On this paper we propose a method which takes into account the time-dependence of the normalization factor. From a generic form for the deviation density matrix an expression for the relaxing initial pure state is deduced. The method is exemplified with an experiment of relaxation of the concurrence of a pseudo-entangled state, which exhibits the phenomenon of sudden death, and the relaxation of the Wigner function of a pseudo-cat state.

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Alzheimer`s disease is an ultimately fatal neurodegenerative disease, and BACE-1 has become an attractive validated target for its therapy, with more than a hundred crystal structures deposited in the PDB. In the present study, we present a new methodology that integrates ligand-based methods with structural information derived from the receptor. 128 BACE-1 inhibitors recently disclosed by GlaxoSmithKline R&D were selected specifically because the crystal structures of 9 of these compounds complexed to BACE-1, as well as five closely related analogs, have been made available. A new fragment-guided approach was designed to incorporate this wealth of structural information into a CoMFA study, and the methodology was systematically compared to other popular approaches, such as docking, for generating a molecular alignment. The influence of the partial charges calculation method was also analyzed. Several consistent and predictive models are reported, including one with r (2) = 0.88, q (2) = 0.69 and r (pred) (2) = 0.72. The models obtained with the new methodology performed consistently better than those obtained by other methodologies, particularly in terms of external predictive power. The visual analyses of the contour maps in the context of the enzyme drew attention to a number of possible opportunities for the development of analogs with improved potency. These results suggest that 3D-QSAR studies may benefit from the additional structural information added by the presented methodology.

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This presentation was offered as part of the CUNY Library Assessment Conference, Reinventing Libraries: Reinventing Assessment, held at the City University of New York in June 2014.

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Company X develops a laboratory information system (LIS) called System Y. The informationsystem has a two-tier database architecture consisting of a production database and a historicaldatabase. A database constitutes the backbone of a IS, which makes the design of the databasevery important. A poorly designed database can cause major problems within an organization.The two databases in System Y are poorly modeled, particularly the historical database. Thecause of the poor modeling was unclear concepts. The unclear concepts have remained in thedatabase and in the company organization and caused a general confusion of concepts. The splitdatabase architecture itself has evolved into a bottleneck and is the cause of many problemsduring the development of System Y.Company X investigates the possibility of integrating the historical database with the productiondatabase. The goal of our thesis is to conduct a consequence analysis of such integration andwhat the effects would be on System Y, and to create a new design for the integrated database.We will also examine and describe the practical effects of confusion of concepts for a databaseconceptual design.To achieve the goal of the thesis, five different method steps have been performed: a preliminarystudy of the organization, a change analysis, a consequence analysis and an investigation of theconceptual design of the database. These method steps have helped identify changes necessaryfor the organization, a new design proposal for an integrated database, the impact of theproposed design and a number of effects of confusion for the database.

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Bakgrund: Internet används globalt inom många områden och aktuell forskning visar att gravida kvinnor använder Internet till att söka information om graviditet och förlossning. En graviditet innebär många frågor hos kvinnan och kvinnor söker efter information för att få en trygghet och försäkran om att allt är normalt med deras hälsa och barnet i magen. Syfte: Syftet är att undersöka gravida kvinnors informationssökning via Internet avseende graviditet och förlossning. Metod: Beskrivande tvärsnittstudie. Datainsamling skedde via en enkätundersökning och data analyserades med deskriptiv och jämförande ansats. Resultat: Nästan alla kvinnor i undersökningen använde Internet för att söka information om graviditet och förlossning. Kvinnorna söker information om barnets utveckling, kost/näring och graviditetslängd i hög utsträckning. Högutbildade kvinnor har andra kriterier för trovärdighet på hemsidor än kvinnor med lägre utbildning. Slutsats: Barnmorskor bör vara medvetna om gravida kvinnors användning av Internet samt själva skapa sig en uppfattning om informationen som de gravida kvinnorna läser på Internet. Vår studie visar att barnmorskors rekommendation av hemsidor på Internet har stor betydelse för gravida kvinnor.  

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Bakgrund: Diabetes Mellitus är kronisk sjukdom som är kopplat till lidande och förlust av livskvalitet. Egenvård är avgörande för att minska de negativa konsekvenserna. Mindre än hälften av alla diabetespatienter uppnår god egenvård. Anledningen är bland annat begränsad kunskap om diabetes och bristande egenvårdsföljsamhet. Införandet av Informations- och kommunikationsteknologi i diabetesvården påbörjades för att förbättra det kliniska resultatet och livskvaliteten för patienter med diabetes typ 2. Syfte: Att beskriva hur information och kommunikationsteknologi kan främja egenvård på distans för patienter med diabetes mellitus typ 2. Metod: Litteraturstudie, där artiklarna söktes i CINAHL, PubMed och Web of Science. Artiklarna som inkluderades var 15 artiklar med kvantitativ, kvalitativ samt mixed metod. Resultat: Resultatet visade att Information och kommunikationsteknologi såsom internet, dator och mobiltelefonbaserade egenvårdsprogram främjade egenvård hos patienter med diabetes typ 2 genom ökad kunskap, ökad medvetenhet, ökad motivation samt förbättrad livsstilsförändring i kost och motion. Slutsats: IKT som hjälpmedel kan underlätta dagliga utmaningarna för patienter med diabetes typ 2 eftersom den täcker kunskapsluckan och därtill ökar patienternas medvetenhet och motivation till egenvård.

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Stock repurchases (or share buy-backs) have become increasingly popular among Australian companies. One of the main aims of announcing a stock repurchase by a listed company is signalling the market that its shares are currently underpriced. When market reacts to the signal, price of the shares is expected to increase immediately after the announcement. While there are several ways of repurchasing shares, 'on-market buy-backs' is the most popular method of stock repurchases in Australia. Australian listed companies have announced more than two hundred on-market share buy-backs over the past three years. The aim of this paper is to examine the information signalling effects of these on-market buy-back announcements. If the signal is considered positively (negatively) by the market, the price of the repurchasing company's shares should increase (decrease) immediately after the announcement. If there is no information content in the announcement, the price will remain the same. In this study, signalling effect of share buy-back announcements was examined using most recent Australian data. The total population of on-market buy-back announcements during the period from January 1, 2000 to March 10, 2003 was included. The abnormal market return over the short-run (announcement day and 9 trading days centred on the announcement date) was computed using the All Ordinaries Accumulation Index as the reference portfolio. The daily Abnormal Returns (AR) and Cumulative Abnormal Returns (CAR) during the event period were computed. The results strongly support the information-signalling hypothesis of share buy..backs. Australian market generally considers announcement of on~market share repurchases as signalling of insider information that shares are currently underpriced.

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The use of participational approaches to system design has been debated for a number of years. Within this paper we describe a method that was used to effectively design information systems and implement computer security countermeasures within an health care environment and shown how it was used in a number of environments.

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Study investigating the telecommunication information needs of people with communication disabilities in Australia. Participants were informed about the project through flyers, letters, e-mail, disability agency contacts, and Web sites. A survey with multiple choice and closed and open-ended items was developed. People with communication disabilities used a hard-copy survey format to facilitate completion. Sixty-five participants age eighteen and over from Victoria, Tasmania, South Australia, and Queensland completed the survey. Preliminary results of the study indicated that the participants requested six text-based adaptations: (1) make information clear and easy to read and understand, (2) use larger print, (3) highlight the key points, (4) use dot points, (5) use visual information, such as photos and communication symbols, and (6) provide a range of oral/audio and visual formats for information. The accessibility characteristics requested by the participants called for the development of text and Web-based formats, and for the development of inclusive design guidelines. The authors concluded that further investigation was required to determine the best possible method of making the information accessible.