988 resultados para Simulation tools


Relevância:

20.00% 20.00%

Publicador:

Resumo:

ABSTRACT The traditional method of net present value (NPV) to analyze the economic profitability of an investment (based on a deterministic approach) does not adequately represent the implicit risk associated with different but correlated input variables. Using a stochastic simulation approach for evaluating the profitability of blueberry (Vaccinium corymbosum L.) production in Chile, the objective of this study is to illustrate the complexity of including risk in economic feasibility analysis when the project is subject to several but correlated risks. The results of the simulation analysis suggest that the non-inclusion of the intratemporal correlation between input variables underestimate the risk associated with investment decisions. The methodological contribution of this study illustrates the complexity of the interrelationships between uncertain variables and their impact on the convenience of carrying out this type of business in Chile. The steps for the analysis of economic viability were: First, adjusted probability distributions for stochastic input variables (SIV) were simulated and validated. Second, the random values of SIV were used to calculate random values of variables such as production, revenues, costs, depreciation, taxes and net cash flows. Third, the complete stochastic model was simulated with 10,000 iterations using random values for SIV. This result gave information to estimate the probability distributions of the stochastic output variables (SOV) such as the net present value, internal rate of return, value at risk, average cost of production, contribution margin and return on capital. Fourth, the complete stochastic model simulation results were used to analyze alternative scenarios and provide the results to decision makers in the form of probabilities, probability distributions, and for the SOV probabilistic forecasts. The main conclusion shown that this project is a profitable alternative investment in fruit trees in Chile.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tutkimuksen tavoitteena oli selvittää miten kehittää yrityksen nykyistä e-palvelujärjestelmää, Internet -teknologiaan perustuvaa sähköisiä kommunikaatio- ja tiedonjakojärjestelmää, yrityksen business-to-business asiakkuuksien johtamisessa. Tavoitteena oli myös luoda ehdotukset uusista e-palvelusopimusmalleista. Tutkimuksen teoriaosuudessa pyrittiin kehittämään aikaisempiin tutkimuksiin, tietokirjallisuuteen ja asiantuntijoihin perustuva viitekehysmalli. Empiirisessä osassa tutkimuksen tavoitteisiin pyrittiin haastattelemalla yrityksen asiakkaita ja henkilöstöä, sekä tarkastelemalla asiakaskontaktien nykyistä tilaa ja kehittymistä. Näiden tietojen perusteella selvitettiin e-palvelun käyttäjien tarpeita, profiilia ja valmiuksia palvelun käyttöön sekä palvelun nykyistä houkuttelevuutta. Tutkimuksen teoriaosan lähdeaineistona käytettiin kirjallisuutta, artikkeleita ja tilastoja asiakashallinnasta sekä e-palveluiden, erityisesti Internet ja verkkopalveluiden markkinoinnista, nykytilasta sekä palveluiden kehittämisestä. Lisäksi tutkittiin kirjallisuutta arvoverkostoanalyysistä, asiakkaan arvosta, informaatioteknologiasta, palvelun laadusta ja asiakastyytyväisyydestä. Tutkimuksen empiirinen osa perustuu yrityksen henkilöstöltä sekä asiakkailta haastatteluissa kerättyihin tietoihin, yrityksen ennalta keräämiin materiaaleihin sekä Taloustutkimuksen keräämiin tietoihin. Tutkimuksessa käytettiin case -menetelmää, joka oli yhdistelmä sekä kvalitatiivista että kvantitatiivista tutkimusta. Casen tarkoituksena oli testata mallin paikkansapitävyyttä ja käyttökelpoisuutta, sekä selvittää onko olemassa vielä muita tekijöitä, jotka vaikuttavat asiakkaan saamaan arvoon. Kvalitatiivinen aineisto perustuu teemahaastattelumenetelmää soveltaen haastateltuihin asiakkaisiin ja yrityksen työntekijöihin. Kvantitatiivinen tutkimus perustuu Taloustutkimuksen tutkimukseen ja yrityksen asiakaskontakteista kerättyyn tietoon. Haastatteluiden perusteella e-palvelut nähtiin hyödyllisinä ja tulevaisuudessa erittäin tärkeinä. E-palvelut nähdään yhtenä tärkeänä kanavana, perinteisten kanavien rinnalla, tehostaa business-to-business -asiakkuuksien johtamista. Tutkimuksen antamien tulosten mukaan asiakkaiden palveluun liittyvän tieto-, taito-, tarpeellisuus- ja kiinnostavuustasojen vaihtelevaisuus osoittaa selvän tarpeen eritasoisille e-palvelupaketti ratkaisuille. Tuloksista muodostettu ratkaisuehdotus käsittää neljän eri e-palvelupaketin rakentamisen asiakkaiden eri tarpeita mukaillen.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tutkimuksen tavoitteena oli selvittää sisäisen kommunikoinnin tilannetta case-yrityksissä. Yritykset kuuluvat kahteen case-arvoverkostoon, jotka toimivat informaatio- ja kommunikaatioteknologian alalla. Sisäinen kommunikointi valittiin tutkimusalueeksi, koska se muodostaa perustan ulkoiselle, yritysten väliselle kommunikoinnille. Tutkimuksen painopiste oli web-pohjaisessa kommunikoinnissa ja webin ominaisuuksissa arvoverkoston näkökulmasta. Tutkimusprosessissa käytettiin sekä kvalitatiivisia että kvantitatiivisia menetelmiä. Tutkimuksen kvantitatiivinen osa toteutettiin web-kyselynä, jonka tulokset osoittivat, että case-yritysten sisäinen kommunikointi perustuu pääasiassa perinteisten kommunikointivälineiden käyttöön. Toisin sanoen, webin hyödyntäminen on vähäistä, mihin vaikuttavat monet eri tekijät. Webissä on kuitenkin useita ominaisuuksia, jotka parantavat kommunikointia arvoverkostossa ja siksi nämä web-pohjaiset välineet tulisi huomioida, kun suunnitellaan yleistä kommunikointijärjestelmää. Tutkimuksen teoreettisessa osassa määriteltiin vuorovaikutteisuus-ominaisuuteen perustuva kommunikointivälineiden luokittelu. Tämän lisäksi määriteltiin myös arvoverkoston käsite. Empiirinen osa koostui web-kyselyn toteutuksen ja tulosten raportoinnista, jonka jälkeen yhteenvetokappale koosti merkittävimmät havainnot sekä mahdolliset jatkotutkimusaiheet.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this study the theoretical part was created to make comparison between different Value at Risk models. Based on that comparison one model was chosen to the empirical part which concentrated to find out whether the model is accurate to measure market risk. The purpose of this study was to test if Volatility-weighted Historical Simulation is accurate in measuring market risk and what improvements does it bring to market risk measurement compared to traditional Historical Simulation. Volatility-weighted method by Hull and White (1998) was chosen In order to improve the traditional methods capability to measure market risk. In this study we found out that result based on Historical Simulation are dependent on chosen time period, confidence level and how samples are weighted. The findings of this study are that we cannot say that the chosen method is fully reliable in measuring market risk because back testing results are changing during the time period of this study.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

OBJECTIVES: Repair of the right ventricular outflow tract (RVOT) in paediatric cardiac surgery remains challenging due to the high reoperation rate. Intimal hyperplasia and consequent arteriosclerosis is one of the most important limitation factors for graft durability. Since local shear stress and pressure are predictive elements for intimal hyperplasia and wall degeneration, we sought to determine in an oversized 12-mm RVOT model, with computed fluid dynamics simulation, the local haemodynamical factors that may explain intimal hyperplasia. This was done with the aim of identifying the optimal degree of oversizing for a 12-mm native RVOT. METHODS: Twenty domestic pigs, with a weight of 24.6 ± 0.89 kg and a native RVOT diameter of 12 ± 1.7 mm, had valve conduits of 12, 16, 18 and 20 mm implanted. Pressure and flow were measured at 75, 100 and 125% of normal flow at RVOT at the pulmonary artery, pulmonary artery bifurcation and at the left and right pulmonary arteries. Three-dimensional computed fluid dynamics (CFD) simulation in all four geometries in all flow modalities was performed. Local shear stress and pressure conditions were investigated. RESULTS: Corresponding to 75, 100 and 125% of steady-state flow, three inlet velocity profiles were obtained, 0.2, 0.29 and 0.36 m/s, respectively. At inflow velocity profiles, low shear stress areas, ranged from 0 to 2 Pa, combined with high-pressure areas ranging from 11.5 to 12.1 mmHg that were found at distal anastomosis, at bifurcation and at the ostia of the left and right pulmonary arteries in all geometries. CONCLUSIONS: In all three oversized geometries, the local reparation of shear stress and pressure in the 16-mm model showed a similar local profile as in the native 12 mm RVOT. According to these findings, we suggest oversizing the natural 12-mm RVOT by not more than 4 mm. The elements responsible for wall degeneration and intimal hyperplasia remain very similar to the conditions present in native RVOT.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Optical trapping is an attractive and multidisciplinary topic that has become the center of attention to a large number of researchers. Moreover, it is a suitable subject for advanced students that requires a knowledge of a wide range of topics. As a result, it has been incorporated into some syllabuses of both undergraduate and graduate programs. In this paper, basic concepts in laser trapping theory are reviewed. To provide a better understanding of the underlying concepts for students, a Java application for simulating the behavior of a dielectric particle trapped in a highly focused beam has been developed. The program illustrates a wide range of theoretical results and features, such as the calculation of the force exerted by a beam in the Mie and Rayleigh regimes or the calibration of the trap stiffness. Some examples that are ready to be used in the classroom or in the computer lab are also supplied.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This thesis analyses the calculation of FanSave and PumpSave energy saving tools calculation. With these programs energy consumption of variable speed drive control for fans and pumps can be compared to other control methods. With FanSave centrifugal and axial fans can be examined and PumpSave deals with centrifugal pumps. By means of these programs also suitable frequency converter can be chosen from the ABB collection. Programs need as initial values information about the appliances like amount of flow and efficiencies. Operation time is important factor when calculating the annual energy consumption and information about it are the length and profile. Basic theory related to fans and pumps is introduced without more precise instructions for dimensioning. FanSave and PumpSave contain various methods for flow control. These control methods are introduced in the thesis based on their operational principles and suitability. Also squirrel cage motor and frequency converter are introduced because of their close involvement to fans and pumps. Second part of the thesis contains comparison between results of FanSave’s and PumpSave’s calculation and performance curve based calculation. Also laboratory tests were made with centrifugal and axial fan and also with centrifugal pump. With the results from this thesis the calculation of these programs can be adjusted to be more accurate and also some new features can be added.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We have studied how leaders emerge in a group as a consequence of interactions among its members. We propose that leaders can emerge as a consequence of a self-organized process based on local rules of dyadic interactions among individuals. Flocks are an example of self-organized behaviour in a group and properties similar to those observed in flocks might also explain some of the dynamics and organization of human groups. We developed an agent-based model that generated flocks in a virtual world and implemented it in a multi-agent simulation computer program that computed indices at each time step of the simulation to quantify the degree to which a group moved in a coordinated way (index of flocking behaviour) and the degree to which specific individuals led the group (index of hierarchical leadership). We ran several series of simulations in order to test our model and determine how these indices behaved under specific agent and world conditions. We identified the agent, world property, and model parameters that made stable, compact flocks emerge, and explored possible environmental properties that predicted the probability of becoming a leader.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Molecular dynamics simulations were performed to study the ion and water distribution around a spherical charged nanoparticle. A soft nanoparticle model was designed using a set of hydrophobic interaction sites distributed in six concentric spherical layers. In order to simulate the effect of charged functionalyzed groups on the nanoparticle surface, a set of charged sites were distributed in the outer layer. Four charged nanoparticle models, from a surface charge value of −0.035 Cm−2 to − 0.28 Cm−2, were studied in NaCl and CaCl2 salt solutions at 1 M and 0.1 M concentrations to evaluate the effect of the surface charge, counterion valence, and concentration of added salt. We obtain that Na + and Ca2 + ions enter inside the soft nanoparticle. Monovalent ions are more accumulated inside the nanoparticle surface, whereas divalent ions are more accumulated just in the plane of the nanoparticle surface sites. The increasing of the the salt concentration has little effect on the internalization of counterions, but significantly reduces the number of water molecules that enter inside the nanoparticle. The manner of distributing the surface charge in the nanoparticle (uniformly over all surface sites or discretely over a limited set of randomly selected sites) considerably affects the distribution of counterions in the proximities of the nanoparticle surface.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The structure of the electric double layer in contact with discrete and continuously charged planar surfaces is studied within the framework of the primitive model through Monte Carlo simulations. Three different discretization models are considered together with the case of uniform distribution. The effect of discreteness is analyzed in terms of charge density profiles. For point surface groups,a complete equivalence with the situation of uniformly distributed charge is found if profiles are exclusively analyzed as a function of the distance to the charged surface. However, some differences are observed moving parallel to the surface. Significant discrepancies with approaches that do not account for discreteness are reported if charge sites of finite size placed on the surface are considered.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

As the development of integrated circuit technology continues to follow Moore’s law the complexity of circuits increases exponentially. Traditional hardware description languages such as VHDL and Verilog are no longer powerful enough to cope with this level of complexity and do not provide facilities for hardware/software codesign. Languages such as SystemC are intended to solve these problems by combining the powerful expression of high level programming languages and hardware oriented facilities of hardware description languages. To fully replace older languages in the desing flow of digital systems SystemC should also be synthesizable. The devices required by modern high speed networks often share the same tight constraints for e.g. size, power consumption and price with embedded systems but have also very demanding real time and quality of service requirements that are difficult to satisfy with general purpose processors. Dedicated hardware blocks of an application specific instruction set processor are one way to combine fast processing speed, energy efficiency, flexibility and relatively low time-to-market. Common features can be identified in the network processing domain making it possible to develop specialized but configurable processor architectures. One such architecture is the TACO which is based on transport triggered architecture. The architecture offers a high degree of parallelism and modularity and greatly simplified instruction decoding. For this M.Sc.(Tech) thesis, a simulation environment for the TACO architecture was developed with SystemC 2.2 using an old version written with SystemC 1.0 as a starting point. The environment enables rapid design space exploration by providing facilities for hw/sw codesign and simulation and an extendable library of automatically configured reusable hardware blocks. Other topics that are covered are the differences between SystemC 1.0 and 2.2 from the viewpoint of hardware modeling, and compilation of a SystemC model into synthesizable VHDL with Celoxica Agility SystemC Compiler. A simulation model for a processor for TCP/IP packet validation was designed and tested as a test case for the environment.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study compares the impact of quality management tools on the performance of organisations utilising the ISO 9001:2000 standard as a basis for a quality-management system band those utilising the EFQM model for this purpose. A survey is conducted among 107 experienced and independent quality-management assessors. The study finds that organisations with qualitymanagement systems based on the ISO 9001:2000 standard tend to use general-purpose qualitative tools, and that these do have a relatively positive impact on their general performance. In contrast, organisations adopting the EFQM model tend to use more specialised quantitative tools, which produce significant improvements in specific aspects of their performance. The findings of the study will enable organisations to choose the most effective quality-improvement tools for their particular quality strategy