987 resultados para Empirical orthogonal functions
Resumo:
It is usually argued that tourism exerts negative economic impacts in host jurisdictions through the increase in prices linked to increasing demand for basic services and goods from tourists. This paper surveys 149 products in 45 tourism and non-tourism jurisdictions in Catalonia (which represent a total of 18,500 prices) in order to test empirically several hypotheses related to differences in price levels in tourism and non-tourism jurisdictions. The main results show that prices in tourism jurisdictions are not significantly higher than those in non-tourism ones. The analysis suggests that tourists are likely to pay higher prices than natives for some products
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The thesis studies role based access control and its suitability in the enterprise environment. The aim is to research how extensively role based access control can be implemented in the case organization and how it support organization’s business and IT functions. This study points out the enterprise’s needs for access control, factors of access control in the enterprise environment and requirements for implementation and the benefits and challenges it brings along. To find the scope how extensively role based access control can be implemented into the case organization, firstly is examined the actual state of access control. Secondly is defined a rudimentary desired state (how things should be) and thirdly completed it by using the results of the implementation of role based access control application. The study results the role model for case organization unit, and the building blocks and the framework for the organization wide implementation. Ultimate value for organization is delivered by facilitating the normal operations of the organization whilst protecting its information assets.
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Recent advances in machine learning methods enable increasingly the automatic construction of various types of computer assisted methods that have been difficult or laborious to program by human experts. The tasks for which this kind of tools are needed arise in many areas, here especially in the fields of bioinformatics and natural language processing. The machine learning methods may not work satisfactorily if they are not appropriately tailored to the task in question. However, their learning performance can often be improved by taking advantage of deeper insight of the application domain or the learning problem at hand. This thesis considers developing kernel-based learning algorithms incorporating this kind of prior knowledge of the task in question in an advantageous way. Moreover, computationally efficient algorithms for training the learning machines for specific tasks are presented. In the context of kernel-based learning methods, the incorporation of prior knowledge is often done by designing appropriate kernel functions. Another well-known way is to develop cost functions that fit to the task under consideration. For disambiguation tasks in natural language, we develop kernel functions that take account of the positional information and the mutual similarities of words. It is shown that the use of this information significantly improves the disambiguation performance of the learning machine. Further, we design a new cost function that is better suitable for the task of information retrieval and for more general ranking problems than the cost functions designed for regression and classification. We also consider other applications of the kernel-based learning algorithms such as text categorization, and pattern recognition in differential display. We develop computationally efficient algorithms for training the considered learning machines with the proposed kernel functions. We also design a fast cross-validation algorithm for regularized least-squares type of learning algorithm. Further, an efficient version of the regularized least-squares algorithm that can be used together with the new cost function for preference learning and ranking tasks is proposed. In summary, we demonstrate that the incorporation of prior knowledge is possible and beneficial, and novel advanced kernels and cost functions can be used in algorithms efficiently.
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Problems related to fire hazard and fire management have become in recent decades one of the most relevant issues in the Wildland-Urban Interface (WUI), that is the area where human infrastructures meet or intermingle with natural vegetation. In this paper we develop a robust geospatial method for defining and mapping the WUI in the Alpine environment, where most interactions between infrastructures and wildland vegetation concern the fire ignition through human activities, whereas no significant threats exist for infrastructures due to contact with burning vegetation. We used the three Alpine Swiss cantons of Ticino, Valais and Grisons as the study area. The features representing anthropogenic infrastructures (urban or infrastructural components of the WUI) as well as forest cover related features (wildland component of the WUI) were selected from the Swiss Topographic Landscape Model (TLM3D). Georeferenced forest fire occurrences derived from the WSL Swissfire database were used to define suitable WUI interface distances. The Random Forest algorithm was applied to estimate the importance of predictor variables to fire ignition occurrence. This revealed that buildings and drivable roads are the most relevant anthropogenic components with respect to fire ignition. We consequently defined the combination of drivable roads and easily accessible (i.e. 100 m from the next drivable road) buildings as the WUI-relevant infrastructural component. For the definition of the interface (buffer) distance between WUI infrastructural and wildland components, we computed the empirical cumulative distribution functions (ECDF) of the percentage of ignition points (observed and simulated) arising at increasing distances from the selected infrastructures. The ECDF facilitates the calculation of both the distance at which a given percentage of ignition points occurred and, in turn, the amount of forest area covered at a given distance. Finally, we developed a GIS ModelBuilder routine to map the WUI for the selected buffer distance. The approach was found to be reproducible, robust (based on statistical analyses for evaluating parameters) and flexible (buffer distances depending on the targeted final area covered) so that fire managers may use it to detect WUI according to their specific priorities.
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This study investigates whether there are differences in profitability of PPI companies based on the growth strategy they have chosen to follow. It is examined whether those companies following organic growth strategy are more profitable than those companies following acquisitive growth strategy. It is also investigated are ones larger than the others, or are ones growing faster than the others. Also, the factors affecting the profitability of acquisitive companies are further examined. The results showed that there actually are differences between the two groups. Organically grown companies were found to be more profitable, smaller and growing slower than acquisitive companies. When it comes to examining only acquisitive companies there could be found factors that better or worsen the profitability of companies. For example targets that the company has bought in developing markets were making them more profitable.
Resumo:
Tämän tutkimuksen tavoitteena oli ymmärtää, miten kohdeyrityksen työntekijöiden osaamisen johtaminen toteutuu. Tutkimus oli luonteeltaan kvalitatiivinen, ja sen empiirinen aineisto koostui kohdeyrityksen kahdeksan esimiehen teemahaastattelusta. Tulosten perusteella voidaan vahvistaa toiminnon osaamisen johtamisen ja osaamisen tunnistamisen toteutuneen toisen kehitysvaiheen mukaisesti. Esimiehet olivat ymmärtäneet työntekijöiden osaamisen merkityksen liiketoimintaa edistävänä tekijänä. Tärkeäksi kehittämisen kohteeksi nousi nykyinen kehityskeskustelukäytäntö, joka tulee muuttaa toiminnon liiketoimintaa ja työntekijöiden osaamista tukevampaan muotoon. Lisäksi esimiehillä oli työntekijöiden osaamisen johtamista varten käytössään erilaisia toimintatapoja ja työvälineitä, joita tulee jatkossa kehittää ja yhtenäistää.
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In this paper we examine whether airline prices on national routes are higher than those charged on international routes. Drawing on a database prepared specifically for this study, we estimate a pricing equation for all routes originating from Gran Canaria, Canary Islands, Spain; differentiating between national and international routes. A key difference between these two route types is that island residents benefit from discounts on domestic flights. When controlling for variables related to airline characteristics, market structure and demand, we find that national passengers who are non-residents on the islands are paying higher prices than international passengers.
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This study examines the short time price effect of dividend announcements during a boom and a recession. The data being used here is gathered from the years of 2000 - 2002 when it was a recession after the techno bubble burst and from the years 2005 - 2007 when investors experienced large capital gains all around the world. The data consists of dividend increases and intact observations. The aim is to find out differences in abnormal returns between a boom and a recession. Second, the study examines differences between different dividend yield brackets. Third, Finnish extra dividends, mainly being delivered to shareholders in 2004 are included to the empirical test. Generally stated, the aim is to find out do investors respect dividends more during a recession than a boom and can this be proved by using dividend yield brackets. The empirical results from U.S shows that the abnormal returns of dividend increase announcements during the recession in the beginning of this decade were larger than during the boom. Thus, investors seem to respect dividend increases more when stock prices are falling. Substantial abnormal returns of dividend increases during the time period of 2005 - 2007 could not be found. The results from the overall samples state that the abnormal returns during the recession were positively slightly higher than during the boom. No clear and strong evidence was found between different dividend yield brackets. In Finland, there were substantial abnormal returns on the announcement day of the extra dividends. Thus, indicating that investors saw the extra dividends as a good thing for shareholders' value. This paper is mostly in line with the theory that investors respect dividends more during bad times than good times.
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Intermunicipal cooperation is being increasingly adopted in various countries as a part of local service delivery reforms. This paper draws on survey data from Spain’s municipalities to examine the reasons underpinning the decisions of local governments to engage in intermunicipal cooperation and privatisation. Our empirical analysis indicates that small municipalities prefer to rely on cooperation for reducing costs, while their larger counterparts prefer to privatise the delivery of services. By cooperating, scale economies can be achieved with lower transaction costs and fewer concerns for competition than is the case via private production.
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Tutkimuksen tavoitteena on tutkia epänormaalien tuottojen esiintymistä nousu- ja laskusuhdanteen aikana osingonilmoituspäivän ympärillä. Osinkoilmoitukset ovat kerätty Yhdysvaltojen markkinalta (NYSE) ajanjaksoilta 2000 - 2002, jolloin pörssit laskivat teknokuplan jälkeen ja 2005 - 2007, jolloin sijoittajat kokivat suuria kurssivoittoja. Osinkoilmoitushavainnot koostuvat yhtiöistä, jotka nostivat tai pitivät osinko per osake paikallaan. Tavoitteena on tutkia eroja epänormaaleissa tuotoissa näiden kahden ajanjakson välillä. Toiseksi, tavoitteena on tutkia miten epänormaalit tuotot poikkeavat toisistaan eri osinkotuottoluokissa. Kolmanneksi, tavoitteena on tutkia esiintyikö markkinoilla epänormaaleja tuottoja kun suomalaiset yritykset ilmoittivat ylimääräisistä osingoista, pääasiassa vuonna 2004. Yksinkertaisesti ja lyhyesti sanottuna tavoitteena on tutkia arvostavatko sijoittajat osinkoja enemmän laskukauden vai nousukauden aikana. Rahoitusteorian mukaan sijoittajien tulisi arvostaa laskukauden aikana enemmän yhtiöitä, jotka pystyvät maksamaan huonosta taloustilanteesta huolimatta hyvää osinkoa. Empiiriset testit Yhdysvalloista osoittavat, että osingon nostamisesta johtuvat epänormaalit tuotot olivat suuremmat laskusuhdanteen aikana kuin noususuhdanteen aikana. Tämä on linjassa teorian kanssa. Osingon-nostot aiheuttivat nousukauden aikana vähäisiä epänormaaleja tuottoja. Selviä eroja eri osingontuottoluokkien välillä ei pystytty havaitsemaan. Tulokset yhdistetystä aineistosta osoittavat, että sijoittajat kokivat vähäisiä positiivisia epänormaaleja tuottoja laskukauden aikana. Nousukautena tuotot olivat lähellä nollaa. Suomen markkinoilla havaittiin selvä epänormaalituotto osingonilmoituspäivänä. Tulokset ovat pääpiirteittäin linjassa teorian kanssa. Sijoittajat arvostavat osinkoja hieman enemmän lasku- kuin noususuhdanteen aikana.
Resumo:
The analysis of vertical industry relations forms an essential element in the field of industrial organization. This paper tests hypotheses derived from transaction cost theory and the principal-agent problem in Chile’s petrol market. It shows that local competition plays an important role in the choice of a disintegrated vertical structure, and that low levels of service investment have the same effect. Conversely, the number of own-brand outlets and a high level of investment in services reduce the probability of disintegration. The paper demonstrates that vertical disintegration has a null effect on wholesale petrol prices and a positive effect on retail petrol prices of between 1.6 and 7 per cent, depending on fuel type.
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The conversion of cellular prion protein (PrPc), a GPI-anchored protein, into a protease-K-resistant and infective form (generally termed PrPsc) is mainly responsible for Transmissible Spongiform Encephalopathies (TSEs), characterized by neuronal degeneration and progressive loss of basic brain functions. Although PrPc is expressed by a wide range of tissues throughout the body, the complete repertoire of its functions has not been fully determined. Recent studies have confirmed its participation in basic physiological processes such as cell proliferation and the regulation of cellular homeostasis. Other studies indicate that PrPc interacts with several molecules to activate signaling cascades with a high number of cellular effects. To determine PrPc functions, transgenic mouse models have been generated in the last decade. In particular, mice lacking specific domains of the PrPc protein have revealed the contribution of these domains to neurodegenerative processes. A dual role of PrPc has been shown, since most authors report protective roles for this protein while others describe pro-apoptotic functions. In this review, we summarize new findings on PrPc functions, especially those related to neural degeneration and cell signaling.
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Objective: The aim of the current study was to investigate the long-term cognitive effects of electroconvulsive therapy (ECT) in a sample of adolescent patients in whom schizophrenia spectrum disorders were diagnosed. Methods: The sample was composed of nine adolescent subjects in whom schizophrenia or schizoaffective disorder was diagnosed according to DSM-IV-TR criteria on whom ECT was conducted (ECT group) and nine adolescent subjects matched by age, socioeconomic status, and diagnostic and Positive and Negative Syndrome Scale (PANSS) total score at baseline on whom ECT was not conducted (NECT group). Clinical and neuropsychological assessments were carried out at baseline before ECT treatment and at 2-year follow-up. Results: Significant differences were found between groups in the number of unsuccessful medication trials. No statistically significant differences were found between the ECT group and theNECT group in either severity as assessed by the PANSS, or in any cognitive variables at baseline.At follow-up, both groups showed significant improvement in clinical variables (subscales of positive, general, and total scores of PANSS and Clinical Global Impressions-Improvement). In the cognitive assessment at follow-up, significant improvement was found in both groups in the semantic category of verbal fluency task and digits forward. However, no significant differences were found between groups in any clinical or cognitive variable at follow-up. Repeated measures analysis found no significant interaction of time · group in any clinical or neuropsychological measures. Conclusions: The current study showed no significant differences in change over time in clinical or neuropsychological variables between the ECT group and the NECT group at 2-year follow-up. Thus, ECT did not show any negative influence on long-term neuropsychological variables in our sample.
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Previous functional MRI (fMRI) studies have associated anterior hippocampus with imagining and recalling scenes, imagining the future, recalling autobiographical memories and visual scene perception. We have observed that this typically involves the medial rather than the lateral portion of the anterior hippocampus. Here, we investigated which specific structures of the hippocampus underpin this observation. We had participants imagine novel scenes during fMRI scanning, as well as recall previously learned scenes from two different time periods (one week and 30 min prior to scanning), with analogous single object conditions as baselines. Using an extended segmentation protocol focussing on anterior hippocampus, we first investigated which substructures of the hippocampus respond to scenes, and found both imagination and recall of scenes to be associated with activity in presubiculum/parasubiculum, a region associated with spatial representation in rodents. Next, we compared imagining novel scenes to recall from one week or 30 min before scanning. We expected a strong response to imagining novel scenes and 1-week recall, as both involve constructing scene representations from elements stored across cortex. By contrast, we expected a weaker response to 30-min recall, as representations of these scenes had already been constructed but not yet consolidated. Both imagination and 1-week recall of scenes engaged anterior hippocampal structures (anterior subiculum and uncus respectively), indicating possible roles in scene construction. By contrast, 30-min recall of scenes elicited significantly less activation of anterior hippocampus but did engage posterior CA3. Together, these results elucidate the functions of different parts of the anterior hippocampus, a key brain area about which little is definitely known.
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This paper seeks to address the problem of the empirical identification of housing market segmentation,once we assume that submarkets exist. The typical difficulty in identifying housing submarkets when dealing with many locations is the vast number of potential solutions and, in such cases, the use of the Chow test for hedonic functions is not a practical solution. Here, we solve this problem by undertaking an identification process with a heuristic for spatially constrained clustering, the"Housing Submarket Identifier" (HouSI). The solution is applied to the housing market in the city of Barcelona (Spain), where we estimate a hedonic model for fifty thousand dwellings aggregated into ten groups. In order to determine the utility of the procedure we seek to verify whether the final solution provided by the heuristic is comparable with the division of the city into ten administrative districts.