796 resultados para Empirical Algorithm Analysis
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The prediction of rockfall travel distance below a rock cliff is an indispensable activity in rockfall susceptibility, hazard and risk assessment. Although the size of the detached rock mass may differ considerably at each specific rock cliff, small rockfall (<100 m3) is the most frequent process. Empirical models may provide us with suitable information for predicting the travel distance of small rockfalls over an extensive area at a medium scale (1:100 000¿1:25 000). "Solà d'Andorra la Vella" is a rocky slope located close to the town of Andorra la Vella, where the government has been documenting rockfalls since 1999. This documentation consists in mapping the release point and the individual fallen blocks immediately after the event. The documentation of historical rockfalls by morphological analysis, eye-witness accounts and historical images serve to increase available information. In total, data from twenty small rockfalls have been gathered which reveal an amount of a hundred individual fallen rock blocks. The data acquired has been used to check the reliability of the main empirical models widely adopted (reach and shadow angle models) and to analyse the influence of parameters which affecting the travel distance (rockfall size, height of fall along the rock cliff and volume of the individual fallen rock block). For predicting travel distances in maps with medium scales, a method has been proposed based on the "reach probability" concept. The accuracy of results has been tested from the line entailing the farthest fallen boulders which represents the maximum travel distance of past rockfalls. The paper concludes with a discussion of the application of both empirical models to other study areas.
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Artifacts are present in most of the electroencephalography (EEG) recordings, making it difficult to interpret or analyze the data. In this paper a cleaning procedure based on a multivariate extension of empirical mode decomposition is used to improve the quality of the data. This is achieved by applying the cleaning method to raw EEG data. Then, a synchrony measure is applied on the raw and the clean data in order to compare the improvement of the classification rate. Two classifiers are used, linear discriminant analysis and neural networks. For both cases, the classification rate is improved about 20%.
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This paper analyses the effect of R&D investment on firm growth. We use an extensive sample of Spanish manufacturing and service firms. The database comprises diverse waves of Spanish Community Innovation Survey and covers the period 2004–2008. First, a probit model corrected for sample selection analyses the role of innovation on the probability of being a high-growth firm (HGF). Second, a quantile regression technique is applied to explore the determinants of firm growth. Our database shows that a small number of firms experience fast growth rates in terms of sales or employees. Our results reveal that R&D investments positively affect the probability of becoming a HGF. However, differences appear between manufacturing and service firms. Finally, when we study the impact of R&D investment on firm growth, quantile estimations show that internal R&D presents a significant positive impact for the upper quantiles, while external R&D shows a significant positive impact up to the median. Keywords : High-growth firms, Firm growth, Innovation activity. JEL Classifications : L11, L25, L26, O30
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Selostus: Maatalouden ympäristöpolitiikan reformien tehokkuus ravinnepäästöjen vähentämisessä - teoreettinen ja empiirinen analyysi
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Coherent anti-Stokes Raman scattering is the powerful method of laser spectroscopy in which significant successes are achieved. However, the non-linear nature of CARS complicates the analysis of the received spectra. The objective of this Thesis is to develop a new phase retrieval algorithm for CARS. It utilizes the maximum entropy method and the new wavelet approach for spectroscopic background correction of a phase function. The method was developed to be easily automated and used on a large number of spectra of different substances.. The algorithm was successfully tested on experimental data.
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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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Peer-reviewed
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User retention is a major goal for higher education institutions running their teaching and learning programmes online. This is the first investigation into how the senses of presence and flow, together with perceptions about two central elements of the virtual education environment (didactic resource quality and instructor attitude), facilitate the user¿s intention to continue e-learning. We use data collected from a large sample survey of current users in a pure e-learning environment along with objective data about their performance. The results provide support to the theoretical model. The paper further offers practical suggestions for institutions and instructors who aim to provide effective e-learning experiences.
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This paper analyses the factors that determine solid waste service costs. The empirical analysis is based on information derived from a survey conducted in a sample of Galician municipalities. The results reveal economies of scale in municipalities of fewer than 50,000 inhabitants, such that cooperation between these municipalities could lead to cost savings. It also appears that private delivery is not cheaper than public delivery. Finally, designating a larger proportion of the total waste volume to recycling does not imply greater costs.
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The agricultural sector has always been characterized by a predominance of small firms. International competition and the consequent need for restraining costs are permanent challenges for farms. This paper performs an empirical investigation of cost behavior in agriculture using panel data analysis. Our results show that transactions caused by complexity influence farm costs with opposite effects for specific and indirect costs. While transactions allow economies of scale in specific costs, they significantly increase indirect costs. However, the main driver for farm costs is volume. In addition, important differences exist for small and big farms, since transactional variables significantly influence the former but not the latter. While sophisticated management tools, such ABC, could provide only limited complementary useful information but no essential allocation bases for farms, they seem inappropriate for small farms
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The agricultural sector has always been characterized by a predominance of small firms. International competition and the consequent need for restraining costs are permanent challenges for farms. This paper performs an empirical investigation of cost behavior in agriculture using panel data analysis. Our results show that transactions caused by complexity influence farm costs with opposite effects for specific and indirect costs. While transactions allow economies of scale in specific costs, they significantly increase indirect costs. However, the main driver for farm costs is volume. In addition, important differences exist for small and big farms, since transactional variables significantly influence the former but not the latter. While sophisticated management tools, such ABC, could provide only limited complementary useful information but no essential allocation bases for farms, they seem inappropriate for small farms
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The empirical literature about factors explaining local government delivery choices has traditionally focused the attention on the public or private production dilemma. However, hybrid organizational forms such as mixed public-private firms are increasingly used in several European countries. This paper makes use of survey data from Spanish municipalities to examine motivations of local governments for engaging in hybrid organizational forms. Data refer to two very relevant local services: water distribution and solid waste collection. The empirical analysis indicates that the use of mixed firms emerge as a type of pragmatically based ‘third way’ between pure public and pure private production. Indeed, local governments make use of mixed firms when cost considerations (scale economies, transaction costs and soon), financial constraints and private interests exert contradictory pressures. On the contrary, political and ideological factors do not play any significant role on the local government decision of engaging or not in joint ventures with private partners.
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The strategic group theory provides an intermediate level of analysis between a single company and the whole industry for identifying issues about the company's competitive position and strategic choices. Strategic groups are companies within an industry with similar strategic characteristics or competing on similar bases. Strategic choices are aligned with the firms’ resources. The purpose of this study was to identify the strategic groups in the wind energy industry in Europe, and study, whether a certain group membership results in financial performance differences. Altogether 80 European wind energy companies were included in the study, which were clustered into four strategic groups according to their age and growth rate. Each group corresponds to a different strategy. The results show that the wind energy companies can be clustered according to the chosen strategic characteristics. Strategic decisions were investigated with characteristic variables. Performance variables were used in the analysis measuring profitability, liquidity and solvency of the groups. These strategic choices of the companies did not have a significant influence on the firms’ performance. The more mature and slower growing group proved to be the most successful. However, the differences between groups were generally not statistically significant. The only statistically significant difference found was in the solvency ratio between Mature Slow and Young Rapid groups. Measured with these variables, more mature and slower growing companies performed better. Therefore, a certain strategic group membership results in performance differences.
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This paper examines the extent to which innovative Spanish firms pursue improvements in energy efficiency (EE) as an objective of innovation. The increase in energy consumption and its impact on greenhouse gas emissions justifies the greater attention being paid to energy efficiency and especially to industrial EE. The ability of manufacturing companies to innovate and improve their EE has a substantial influence on attaining objectives regarding climate change mitigation. Despite the effort to design more efficient energy policies, the EE determinants in manufacturing firms have been little studied in the empirical literature. From an exhaustive sample of Spanish manufacturing firms and using a logit model, we examine the energy efficiency determinants for those firms that have innovated. To carry out the econometric analysis, we use panel data from the Community Innovation Survey for the period 2008‐2011. Our empirical results underline the role of size among the characteristics of firms that facilitate energy efficiency innovation. Regarding company behaviour, firms that consider the reduction of environmental impacts to be an important objective of innovation and that have introduced organisational innovations are more likely to innovate with the objective of increasing energy efficiency. Keywords: energy efficiency, corporate targets, innovation, Community Innovation Survey. JEL Classification: Q40, Q55, O31
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Energy industry has gone through major changes globally in past two decades. Liberalization of energy markets has led companies to integrate both vertically and horizontally. Growing concern on sustainable development and aims to decrease greenhouse gases in future will increase the portion of renewable energy in total energy production. Purpose of this study was to analyze using statistical methods, what impacts different strategic choices has on biggest European and North American energy companies’ performance. Results show that vertical integration, horizontal integration and use of renewable energy in production had the most impact on profitability. Increase in level of vertical integration decreased companies’ profitability, while increase in horizontal integration improved companies’ profitability. Companies that used renewable energy in production were less profitable than companies not using renewable energy.