919 resultados para Linear network analysis


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This is a study of team social networks, their antecedents and outcomes. In focusing attention on the structural configuration of the team this research contributes to a new wave of thinking concerning group social capital. The research site was a random sample of Finnish work organisations. The data consisted of 499 employees in 76 teams representing 48 different organisations. A systematic literature review and quantitative methods were used in conducting the research: the former primarily to establish the current theoretical position on the relationships among the variables and the latter to test these relationships. Social network analysis was the primary method used in identifying the social-network relations among the work-team members. The first and key contribution of this study is that it relates the structuralnetwork properties of work teams to behavioural outcomes, attitudinal outcomes and, ultimately, team performance. Moreover, it shows that addressing attitudinal outcomes is also important in terms of team performance; attitudinal outcomes (team identity) mediated the relationship between the team’s performance and its social network. The second contribution is that it examines the possible antecedents of the social structure. It is thus one response to Salancik’s (1995) call for a network theory in that it explains why certain network characteristics exist. Itdemonstrates that irrespective of whether or not a team is heterogeneous in terms of age or gender, educational diversity may protect it from centralisation. However, heterogeneity in terms of gender turned out to have a negative impact on density. Thirdly, given the observation that the benefits of (team) networks are typically theorised and modelled without reference to the nature of the relationships comprising the structure, the study directly tested whether team knowledge mediated the effects of instrumental and expressive network relationships on team performance. Furthermore, with its focus on expressive networks that link the workplace to a more informal world, which have been rather neglected in previous research, it enhances knowledge of teams andnetworks. The results indicate that knowledge sharing fully mediates the influence of complementarities between dense and fragmented instrumental network relationships, thus providing empirical validation of the implicit understanding that networks transfer knowledge. Fourthly, the study findings suggest that an optimal configuration of the work-team social-network structure combines both bridging and bonding social relationships.

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Strategic development of distribution networks plays a key role in the asset management in electricity distribution companies. Owing to the capital-intensive nature of the field and longspan operations of companies, the significance of a strategy is emphasised. A well-devised strategy combines awareness of challenges posed by the operating environment and the future targets of the distribution company. Economic regulation, ageing infrastructure, scarcity of resources and tightening supply requirements with challenges created by the climate change put a pressure on the strategy work. On the other hand, technology development related to network automation and underground cabling assists in answering these challenges. This dissertation aims at developing process knowledge and establishing a methodological framework by which key issues related to network development can be addressed. Moreover, the work develops tools by which the effects of changes in the operating environment on the distribution business can be analysed in the strategy work. To this end, the work discusses certain characteristics of the distribution business and describes the strategy process at a principle level. Further, the work defines the subtasks in the strategy process and presents the key elements in the strategy work and long-term network planning. The work delineates the factors having either a direct or indirect effect on strategic planning and development needs in the networks; in particular, outage costs constitute an important part of the economic regulation of the distribution business, reliability being thus a key driver in network planning. The dissertation describes the methodology and tools applied to cost and reliability analyses in the strategy work. The work focuses on determination of the techno-economic feasibility of different network development technologies; these feasibility surveys are linked to the economic regulation model of the distribution business, in particular from the viewpoint of reliability of electricity supply and allowed return. The work introduces the asset management system developed for research purposes and to support the strategy work, the calculation elements of the system and initial data used in the network analysis. The key elements of this asset management system are utilised in the dissertation. Finally, the study addresses the stages of strategic decision-making and compilation of investment strategies. Further, the work illustrates implementation of strategic planning in an actual distribution company environment.

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The concentration of 15 polycyclic aromatic hydrocarbons (PAHs) in 57 samples of distillates (cachaça, rum, whiskey, and alcohol fuel) has been determined by HPLC-Fluorescence detection. The quantitative analytical profile of PAHs treated by Partial Least Square - Discriminant Analysis (PLS-DA) provided a good classification of the studied spirits based on their PAHs content. Additionally, the classification of the sugar cane derivatives according to the harvest practice was obtained treating the analytical data by Linear Discriminant Analysis (LDA), using naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, benz[b]fluoranthene, and benz[g,h,i]perylene, as a chemical descriptors.

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Bulk and supported molybdenum based catalysts, modified by nickel, phosphorous or tungsten were studied by NEXAFS spectroscopy at the Mo L III and L II edges. The techniques of principal component analysis (PCA) together with a linear combination analysis (LCA) allowed the detection and quantification of molybdenum atoms in two different coordination states in the oxide form of the catalysts, namely tetrahedral and octahedral coordination.

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In this paper we built three co-authorship networks displaying the acquaintances between countries, universities and authors that have published papers in Quimica Nova from 1995 to 2008. Our research was conducted applying a bibliometric approach to 1782 papers and over 4200 authors. Centrality measures were used and the most significant actors of each network were pointed out. The results using the centrality metrics and the network structures indicated that Quimica Nova resembles a typical scientific community.

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AbstractMany well-established methods for determining the antioxidant capacities in several samples have been described in literature. However, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) are the main two methods that utilize radicals as spectrophotometric probes for analysis. Nevertheless, these methods have certain limitations because of their slower kinetics, solvent polarity effects, the hydrophilicity and lipophilicity of the compounds, chemical costs, etc. In this study, a spectrophotometric method for determining the antioxidant capacity in beverages was developed based on an exploration of the cation radical derived from DEPD. This method was based on the oxidation of aromatic amines with Fe(III) ions at pH 4.0, which leads to their corresponding purple cation radicals (DEPD•+) with λmax values at 500 and 540 nm. The addition of an antioxidant after the formation of the radical leads to a reduction in color intensity that is proportional to the antioxidant concentration in the medium. Results obtained using this method were compared with the Folin-Ciocalteau, ABTS and DPPH methods in terms of applications in wines, teas, and infusions samples. Linear correlation analysis at a 95% confidence level was employed to compare the results, which were in good agreement with a correlation coefficient of r > 0.9000. Thus, the developed method was simple, accurate, and consistent with other assays for the determination of the total amount of phenolic compounds and antioxidant capacity.

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AbstractThe purpose of this study was to evaluate the best operating conditions of ICP OES for the determination of Na, Ca, Mg, Sr and Fe in aqueous extract of crude oil obtained after hot extraction with organic solvents (ASTM D 6470-99 modified). Thus, the full factorial design and central composite design were used to optimize the best conditions for the flow of nebulization gas, the flow of auxiliary gas, and radio frequency power. After optimization of variables, a study to obtain correct classification of the 18 samples of aqueous extract of crude oils (E1 to E18) from three production and refining fields was carried out. Exploratory analysis of these extracts was performed by principal component analysis (PCA), hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA), using the original variables as the concentration of the metals Na, Ca, Mg, Sr and Fe determined by ICP OES.

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Appearance of trust in regional, co-operative networks In our times, the value of social networks has been widely acknowledged. One can say that it is important for private persons to get networked, whilst it is even a must for companies and organizations in business life. This doctor's thesis examines three co-operative regional networks. Networks are located in Western Uusimaa (Länsi-Uusimaa) region in southernmost Finland, and they had both public organizations and private companies as participants (later called ‘players’). Initially, all of them were co-financed from public funds, and two of them are still operational while writing this. The main target of these networks has been to act as learning networks. The learning network stands for an ensemble of research and development units and workplaces constituting a common forum for learning. The main focus in this study has been on qualitative and structural characteristics of the networks, and how they are relating with intrinsic trust. In addition to the development of trust, it has been studied, at what level organizational learning within the networks takes place, and lastly, what kind of factors facilitate the development of social capital. The theoretical framework for the study is built on analysing trust and social capital. It is a 'mission impossible' to find single definitions for such major concepts. In this study, from the research questions' point of view it has been more relevant to concentrate on the aspects of networking and the relationships between the participating organizations. The total view in this study is very network-centric, and therefore those theories which have similar point of view have been prioritized. Such is the theory about structural holes by Ronald S. Burt (1992). It has been widely applied; especially his views on constraints affecting players in networks. The purpose of this study has not been to create new theories or to analyse and compare thoroughly the existing theoretical trends. Instead, the existing theories have provided the study with conceptual tools, which have been utilized for supporting the empirical results. The aim has been to create an explanatory case study consisting relevant discussion on the relationship between the network characteristics and the appearance of trust. The conceptual categorization for confidence vs. trust created by Niklas Luhmann (1979) is another important theoretical building block. In most cases, co-operation in networks is initiated by people already trusting in each other and willing to work together. However, personal trust is not sufficient in the long run to sustain the co-operation within the network: more abstract systemic trust described by Luhmann must also emerge. In the networks with different structures and at different development phases, these forms of trust appear at different levels. In this study, Luhmann’s systemic trust as a term has been replaced by the concept of 'trust in network as a system'. Structural characteristics of a network (density, centrality, structural holes etc.) have been selected to explain the creation of social capital and trust. The ability to adapt new information is essential for the development of social capital. Qualitative analysis for development phase has been used, and the Learning Network Maturity Test by Leenamaija Otala (2000) and her work have been applied. Thus, the qualitative characteristics and the structural characteristics of the networks are utilized together, when the creation of social capital and appearance of trust are assessed. Social Network Analysis, questionnaires and interviews have been the research methods. Quantitative and qualitative data have been combined. There is a similarity in viewpoints to research data with Extensive Case Study method, in which different cases are searched by exploring various cases and comparing certain common features between them and generic models. Development of trust, social capital and organizational learning has been explained in the study by comparing the networks in hand. Being a case study, it doesn't have targets to provide with general results and findings like conventional surveys. However, in this work phenomena and mechanisms related to them are interpreted from the empirical data. Key finding of this study is that the networks with high structural equality and clear target setting enable building trust to the network as a system. When systemic trust is present, e.g. changes in personnel involved in the co-operation won't hinder the network from remaining operational. On the other hand, if the players are not well motivated to co-operate, if the network is extremely centralized structurally, or if the network has players holding very much more beneficial position compared to the others, systemic trust won't develop: trust tends to remain at the personal level, and is directed to some players only. Such networks won't generate results and benefits to its players, and most probably they won’t live very long. In other words, learning networks cannot solely be based on willingness to learn, but also on willingness to co-operate.

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Dirt counting and dirt particle characterisation of pulp samples is an important part of quality control in pulp and paper production. The need for an automatic image analysis system to consider dirt particle characterisation in various pulp samples is also very critical. However, existent image analysis systems utilise a single threshold to segment the dirt particles in different pulp samples. This limits their precision. Based on evidence, designing an automatic image analysis system that could overcome this deficiency is very useful. In this study, the developed Niblack thresholding method is proposed. The method defines the threshold based on the number of segmented particles. In addition, the Kittler thresholding is utilised. Both of these thresholding methods can determine the dirt count of the different pulp samples accurately as compared to visual inspection and the Digital Optical Measuring and Analysis System (DOMAS). In addition, the minimum resolution needed for acquiring a scanner image is defined. By considering the variation in dirt particle features, the curl shows acceptable difference to discriminate the bark and the fibre bundles in different pulp samples. Three classifiers, called k-Nearest Neighbour, Linear Discriminant Analysis and Multi-layer Perceptron are utilised to categorize the dirt particles. Linear Discriminant Analysis and Multi-layer Perceptron are the most accurate in classifying the segmented dirt particles by the Kittler thresholding with morphological processing. The result shows that the dirt particles are successfully categorized for bark and for fibre bundles.

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Diplomityössä kehitettiin harustetun 110 kV kannatuspylvään konsepti tuotteeksi. Pylväs on säänkestävästä teräksestä valmistettu putkipalkkirakenteinen I-pylväs. Tavoitteena oli suunnitella rakenteesta kokonaistaloudellisesti edullinen. Rakenteen suunnittelussa otettiin huomioon valmistus-, kuljetus- ja varastointi- sekä rakentamisnäkökohtia. Työssä perehdyttiin pylväsrakenteiden yksityiskohtiin, putkipalkkien liitosmenetelmiin ja pylvään jalan nivelöintiratkaisuihin. Säänkestävä rakennemateriaali otettiin huomioon rakennesuunnittelussa. Rakenteen lujuusteknisen suunnittelun apuna käytettiin epälineaarista elementtimenetelmää. Pylväsrakenteen käyttäytyminen mallinnettiin geometrisesti epälineaariseksi, ja liitosdetaljien analysointia varten kehitettiin epälineaarisia materiaalimalleja. Rakenteen värähtelykäyttäytyminen analysoitiin myös elementtimenetelmällä. Lopputuloksena saatiin aikaan pylväs, joka täyttää sille asetetut vaatimukset. Pylväs on helposti valmistettava, kuljetettava ja pystytettävä.

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Measurements of parameters expressed in terms of carbonic species such as Alkalinity and Acidity of saline waters do not analyze the influence of external parameters to the titration such as Total free and associated Carbonic Species Concentration, activity coefficient, ion pairing formation and Residual Liquid Junction Potential in pH measurements. This paper shows the development of F5BC titration function based on the titrations developed by Gran (1952) for the carbonate system of natural waters. For practical use, samples of saline waters from Pocinhos reservoir in Paraiba were submitted to titration and linear regression analysis. Results showed that F5BC involves F1x and F2x Gran functions determination, respectively, for Alkalinity and Acidity calculations without knowing "a priori" the endpoint of the titration. F5BC also allows the determination of the First and Second Apparent Dissociation Constant of the carbonate system of saline and high ionic strength waters.

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Preference relations, and their modeling, have played a crucial role in both social sciences and applied mathematics. A special category of preference relations is represented by cardinal preference relations, which are nothing other than relations which can also take into account the degree of relation. Preference relations play a pivotal role in most of multi criteria decision making methods and in the operational research. This thesis aims at showing some recent advances in their methodology. Actually, there are a number of open issues in this field and the contributions presented in this thesis can be grouped accordingly. The first issue regards the estimation of a weight vector given a preference relation. A new and efficient algorithm for estimating the priority vector of a reciprocal relation, i.e. a special type of preference relation, is going to be presented. The same section contains the proof that twenty methods already proposed in literature lead to unsatisfactory results as they employ a conflicting constraint in their optimization model. The second area of interest concerns consistency evaluation and it is possibly the kernel of the thesis. This thesis contains the proofs that some indices are equivalent and that therefore, some seemingly different formulae, end up leading to the very same result. Moreover, some numerical simulations are presented. The section ends with some consideration of a new method for fairly evaluating consistency. The third matter regards incomplete relations and how to estimate missing comparisons. This section reports a numerical study of the methods already proposed in literature and analyzes their behavior in different situations. The fourth, and last, topic, proposes a way to deal with group decision making by means of connecting preference relations with social network analysis.

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Tutkielman tavoitteena on tehdä katsaus asuntosijoittamiseen sekä löytää asuntosijoittajalle tärkeää tietoa asuntojen hinta- ja vuokrakehitykseen vaikuttavista alueellisista tekijöistä. Asuntojen hintoihin vaikuttavia tekijöitä tutkitaan sekä kasvukaupungeissa että rakennemuutosalueilla. Asuntojen vuokrakehitykseen vaikuttavia selittäviä tekijöitä tutkitaan koko Suomen, pääkaupunkiseudun ja muun Suomen alueilla. Tutkimus toteutetaan käyttäen lineaarista regressioanalyysiä ja käytettävä aineisto koostuu muuttujien aikasarjoista vuosilta 1988–2010 sekä 1996–2009. Saatujen tulosten perusteella nettokansantulolla ja asuntokunnan käytet-tävissä olevalla rahatulolla on selkeä vaikutus asuntojen hintakehitykseen kasvukeskuksissa. Rakennemuutosalueilla työllisyyden ja teollisuuden vaikutukset ovat vahvoja. Asuntojen vuokriin vaikuttavista tekijöistä mm. asuinkerrostalokannalla, aloittaneiden yritysten määrällä ja asuntokunnan käytettävissä olevalla rahatulolla voidaan nähdä olevan selkeä vaikutus neliövuokran kehitykseen.

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Nykypäivän entisestään kovenevassa globaalissa liiketoimintaympäristössä jatkuvan ja pitkäaikaisen kilpailukyvyn ylläpitämiseen ja kehittämiseen vaaditaan laajalti kyvykkyyksiä, kompetensseja ja erilaisia resursseja. Etenkään pienet yritykset eivät pysty vastaamaan nykypäivän liiketoiminnan vaatimuksiin ja tavoitteisiin, jolloin ne tarvitsevat osaamista ja resursseja ulkopuolisilta toimijoilta, jopa mahdollisilta kilpailijoiltaan. Painotus on kilpailutilanteessa siirtynyt yksittäisistä yrityksistä verkostojen välisiksi turnauksiksi liiketoiminnan armottomilla pelikentillä. Diplomityö pohjautuu Lappeenrannan teknillisen yliopiston tutkimuskeskuksessa (TBRC) toteutettuun moniosaiseen tutkimukseen lämpöliiketoiminnan verkostorakenteista ja niiden ominaisuuksista. Tavoitteena on yleisen tietouden kasvattaminen pienten lämpölaitosalan toimijoiden verkostorakenteista, niiden eroista ja tulevaisuuden kehitysmahdollisuuksista. Pääpaino diplomityössä on juuri verkostojen kuvaamisella ja tietouden kasvattamisella, mutta myös rakenteiden ja toimintojen kehittämisessä vertikaalisen ja horisontaalisen verkostokehityksen viitekehyksen avulla, huomioiden operatiiviset ja strategiset tarpeet kilpailukyvyn ylläpitämisessä. Tutkimuksessa tunnistettiin huomattavia eroavaisuuksia lämpölaitosten toiminta-tavoissa sekä verkostorakenteissa ja niissä tapahtuvissa transaktioissa. Kirjallisuudessa esitettyjä onnistuneiden ja tehokkaasti toimivien verkostojen ominaisuuksien korrelaatioita lämpöliiketoiminnan operatiivisiin ja strategisiin toimintoihin vertaillaan tarkoitukseen muokatulla laadun talo -matriisilla. Tärkeimmiksi tulevaisuuden kehityskohteiksi analyysien perusteella havaittiin resurssien ja tietotaidon tehokkaamman jakamisen, yhteistyösuhteiden laajuuksien ja lukumäärien kasvattamisen sekä yhteistyösuhteiden strategisuuden lisäämisen.

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The objective of this study was research the shared knowledge and the means of sharing with the help of social network analysis. The purpose of this study was to give descriptive information to case-organization about its situational network status in different units. The premise of the study is the success of organizational competences and networks, especially when it comes to the sharing of knowledge. The research was accomplished in a TEKES –projects, Developing Network-Based Services – The Role of Competences and Networks COMNET –projects case-organization. Lappeenranta School of Business and the case-organization started the project in co-operation. The baseline for the study was organizational competencies and organizational networks as success factors, especially from the knowledge sharing’s point of view. The research was based on triangulation, which included pre-interviews, network analyses accomplished by Webropol –e-mail survey and qualitative interviews. The results indicated that regular unit meetings were experienced to be the most important method of knowledge sharing along with e-mailing, intranet and weekly bulletins. The co-operation between units was also experienced to be important when evaluating knowledge sharing and communication. The intrafirm network was experienced tight. Dispersed units and partly unclear means of information sharing were the biggest obstacles for information communication. Knowledge sharing, communication with others and trainings were seen important in the case-organization.