From caging to rouse dynamics in polymer melts with intramolecular barriers: a critical test of the mode coupling theory

By means of computer simulations and solution of the equations of the mode coupling theory (MCT),we investigate the role of the intramolecular barriers on several dynamic aspects of nonentangled polymers. The investigated dynamic range extends from the caging regime characteristic of glass-formers to the relaxation of the chain Rouse modes. We review our recent work on this question,provide new results, and critically discuss the limitations of the theory. Solutions of the MCT for the structural relaxation reproduce qualitative trends of simulations for weak and moderate barriers. However, a progressive discrepancy is revealed as the limit of stiff chains is approached. This dis-agreement does not seem related with dynamic heterogeneities, which indeed are not enhanced by increasing barrier strength. It is not connected either with the breakdown of the convolution approximation for three-point static correlations, which retains its validity for stiff chains. These findings suggest the need of an improvement of the MCT equations for polymer melts. Concerning the relaxation of the chain degrees of freedom, MCT provides a microscopic basis for time scales from chain reorientation down to the caging regime. It rationalizes, from first principles, the observed deviations from the Rouse model on increasing the barrier strength. These include anomalous scaling of relaxation times, long-time plateaux, and nonmonotonous wavelength dependence of the mode correlators.

Simulaatiopeli menetelmänä siirtää ikääntyvien hiljaista tietoa. Case: Salon Seudun Osuuspankki

Tutkimuksen tavoitteena oli selvittää, miten simulaatiopeli soveltuu ikääntyvien työntekijöiden hiljaisen tiedon esille tuomiseen ja tiedon siirtämiseen. case - tapauksena tutkimuksessa käytettiin Salon Seudun Osuuspankissapelattua simulaatiopeliä ja tutkimustulokset perustuvat peliin osallistuneiden ko. pankin työntekijöiden näkemyksiin ja mielipiteisiin. Tutkimuksessa selvitettiin miten osallistujat kokevat simulaatiopelin tilanteena, mitkä ovat simulaatiopelin heikkoudet ja vahvuudet hiljaisen tiedon siirrossa sekä millä tavalla simulaatiopeliä tulisi käyttää siirrettäessä hiljaista tietoa. Lisäksi selvitettiin mitä hiljainen tieto pankkityössä on. Tutkimus toteutettiin teemahaastatteluin marraskuussa 2004. Tutkimuksen tuloksena selvisi, että simulaatiopeliä ei nähdä kovin käyttökelpoisena, itsenäisenä hiljaisen tiedon siirron menetelmänä. Merkittävimpinä syinä tähän on simulaatiopelin keinotekoisuus, epäaitous sekä tilanteen jännittävyys. Simulaatiopelin vahvuudeksi hiljaisen tiedon siirrossa koetaan sen erinomainen havainnollistava voima. Simulaatiopeliä voitaisiinkin kokeilla apuna hiljaisen tiedon siirrossa osana pidempää tiedon siirron prosessia.

From caging to rouse dynamics in polymer melts with intramolecular barriers: a critical test of the mode coupling theory

By means of computer simulations and solution of the equations of the mode coupling theory (MCT),we investigate the role of the intramolecular barriers on several dynamic aspects of nonentangled polymers. The investigated dynamic range extends from the caging regime characteristic of glass-formers to the relaxation of the chain Rouse modes. We review our recent work on this question,provide new results, and critically discuss the limitations of the theory. Solutions of the MCT for the structural relaxation reproduce qualitative trends of simulations for weak and moderate barriers. However, a progressive discrepancy is revealed as the limit of stiff chains is approached. This dis-agreement does not seem related with dynamic heterogeneities, which indeed are not enhanced by increasing barrier strength. It is not connected either with the breakdown of the convolution approximation for three-point static correlations, which retains its validity for stiff chains. These findings suggest the need of an improvement of the MCT equations for polymer melts. Concerning the relaxation of the chain degrees of freedom, MCT provides a microscopic basis for time scales from chain reorientation down to the caging regime. It rationalizes, from first principles, the observed deviations from the Rouse model on increasing the barrier strength. These include anomalous scaling of relaxation times, long-time plateaux, and nonmonotonous wavelength dependence of the mode correlators.

Games in Education and Process Development

The aim of the thesis is to devise a framework for analyzing simulation games, in particular introductory supply chain simulation games which are used in education and process development. The framework is then applied to three case examples which are introductory supply chain simulation games used at Lappeenranta University of Technology. The theoretical part of the thesis studies simulation games in the context of education and training as well as of process management. Simulation games can be seen as learning processes which comprise of briefing, micro cycle, and debriefing which includes observation and reflection as well as conceptualization. The micro cycle, i.e. the game itself, is defined through elements and characteristics. Both briefing and debriefing ought to support the micro cycle. The whole learning process needs to support learning objectives of the simulation game. Based on the analysis of the case simulation games, suggestions on how to boost the debriefing and promote long term effects of the games are made. In addition, a framework is suggested to be used in designing simulation games and characteristics of introductory supply chain simulation games are defined. They are designed for general purposes, are simple and operated manually, are multifunctional interplays, and last about 2.5 4 hours. Participants co operate during a game run and competition arises between different runs or game sessions.

Performance of Supply Chain when using selected Coordination Mechanisms

Coordination among supply chain members is essential for better supply chain performance. An effective method to improve supply chain coordination is to implement proper coordination mechanisms. The primary objective of this research is to study the performance of a multi-level supply chain while using selected coordination mechanisms separately, and in combination, under lost sale and back order cases. The coordination mechanisms used in this study are price discount, delay in payment and different types of information sharing. Mathematical modelling and simulation modelling are used in this study to analyse the performance of the supply chain using these mechanisms. Initially, a three level supply chain consisting of a supplier, a manufacturer and a retailer has been used to study the combined effect of price discount and delay in payment on the performance (profit) of supply chain using mathematical modelling. This study showed that implementation of individual mechanisms improves the performance of the supply chain compared to ‘no coordination’. When more than one mechanism is used in combination, performance in most cases further improved. The three level supply chain considered in mathematical modelling was then extended to a three level network supply chain consisting of a four retailers, two wholesalers, and a manufacturer with an infinite part supplier. The performance of this network supply chain was analysed under both lost sale and backorder cases using simulation modelling with the same mechanisms: ‘price discount and delay in payment’ used in mathematical modelling. This study also showed that the performance of the supply chain is significantly improved while using combination of mechanisms as obtained earlier. In this study, it is found that the effect (increase in profit) of ‘delay in payment’ and combination of ‘price discount’ & ‘delay in payment’ on SC profit is relatively high in the case of lost sale. Sensitivity analysis showed that order cost of the retailer plays a major role in the performance of the supply chain as it decides the order quantity of the other players in the supply chain in this study. Sensitivity analysis also showed that there is a proportional change in supply chain profit with change in rate of return of any player. In the case of price discount, elasticity of demand is an important factor to improve the performance of the supply chain. It is also found that the change in permissible delay in payment given by the seller to the buyer affects the SC profit more than the delay in payment availed by the buyer from the seller. In continuation of the above, a study on the performance of a four level supply chain consisting of a manufacturer, a wholesaler, a distributor and a retailer with ‘information sharing’ as coordination mechanism, under lost sale and backorder cases, using a simulation game with live players has been conducted. In this study, best performance is obtained in the case of sharing ‘demand and supply chain performance’ compared to other seven types of information sharing including traditional method. This study also revealed that effect of information sharing on supply chain performance is relatively high in the case of lost sale than backorder. The in depth analysis in this part of the study showed that lack of information sharing need not always be resulting in bullwhip effect. Instead of bullwhip effect, lack of information sharing produced a huge hike in lost sales cost or backorder cost in this study which is also not favorable for the supply chain. Overall analysis provided the extent of improvement in supply chain performance under different cases. Sensitivity analysis revealed useful insights about the decision variables of supply chain and it will be useful for the supply chain management practitioners to take appropriate decisions.

Jogo da Minoria: um modelo baseado em agentes aplicado ao mercado financeiro

Nos últimos anos houve uma contribuição significativa dos físicos para a construção de um tipo de modelo baseado em agentes que busca reproduzir, em simulação computacional, o comportamento do mercado financeiro. Esse modelo, chamado Jogo da Minoria consiste de um grupo de agentes que vão ao mercado comprar ou vender ativos. Eles tomam decisões com base em estratégias e, por meio delas, os agentes estabelecem um intrincado jogo de competição e coordenação pela distribuição da riqueza. O modelo tem demonstrado resultados bastante ricos e surpreendentes, tanto na dinâmica do sistema como na capacidade de reproduzir características estatísticas e comportamentais do mercado financeiro. Neste artigo, são apresentadas a estrutura e a dinâmica do Jogo da Minoria, bem como as contribuições recentes relacionadas ao Jogo da Minoria denominado de Grande Canônico, que é um modelo mais bem ajustado às características do mercado financeiro e reproduz as regularidades estatísticas do preço dos ativos chamadas fatos estilizados.

O nível de esforço físico durante o treinamento coletivo no Futsal na categoria Sub 13

Futsal is one of the most popular sports in Brazil, played on five continents, in hundreds of countries, but is still a poorly studied sports science. Among the types of training used in the preparation of soccer players, the collective training is one of the most used because it is a simulation game. The application of the training load is often made in large quantities (volume) with exercise duration and intensity greater than what the athlete can handle. Thus, this study aimed to evaluate the intensity of physical exertion of futsal players of basic category during collective training. We evaluated twenty (N=20) soccer players from two teams with different levels of training. There were ten players on a team federated (FED) and ten players on a team for a project extension (EXT). Samples were collected at the respective locations of training. An evaluation of anthropometric and during collective training heart rate was measured and at the end of each training time blood samples were collected for analysis of blood lactate concentration and perceived exertion of the players. There was significant difference between the two teams only in fat percentage (FED=13,4 e EXT=21,2). The average heart rate during training was 174 ± 12.2 bpm, which corresponds to 84% HRmax. There was significant difference between heart rate and the percentage of HRmax in the two parts of training in both teams. The Federated team players remained most of the time in more intense intensity zone (above 85% HRmax), while the EXT players were most of the time zone of moderate intensity (65-85% HRmax). The rating of perceived exertion (FED=3,5 e EXT=3,2) and blood lactate concentration (FED=2.4 mmol/L and EXT=2.9 mmol/L) showed no significant difference between the two teams and between the two times. During training there was a significant correlation (p= 0.71) between heart rate and lactate concentration. The collective training showed an intensity that is supposed to be...

A methodology to measure coordination of business processes

Coordination of business processes is the management of dependencies where dependencies constrain how the tasks are performed. It has been traditionally done in an intuitive fashion, without paying much attention to the coordination load. Coordination load is being defined as the ratio between the time spent on coordination activities and the total task time. Previous efforts to understand and analyze coordination have resulted in mostly qualitative approaches to categorize and recommend coordination strategies. This research seeks to answer two questions: (1) How can we analyze process coordination problems to improve overall performance? (2) What guidance can we provide to reduce the coordination load of the process and consequently improve the organization's performance? Thus, this effort developed a quantitative measure for coordination load of business processes and a methodology to apply such measure. ^ This effort used a management simulation game to have a controlled laboratory environment enabling the manipulation of the task factors variability, analyzability, and interdependence to measure their impact on coordination load. The hypothesis was that the more variable, non-analyzable, and interdependent a process, the higher the coordination load, and that a higher coordination load would have a negative impact on performance. Coordination load was measured via the surrogate coordination time, and performance via profit. ^ A 22 x 31 full factorial design, with two replicates, was run to observe the impact on the variables coordination time and profit. Properly validated spreadsheets and questionnaires were used as data collection instruments for each scenario. The experimental results indicate that lower task analyzability (ρ=0.036) and higher task interdependence (ρ=0.000) lead to higher coordination load, and higher levels of task variability (ρ=0.049) lead to lower performance. However, contrary to the hypotheses postulated by this work, coordination load did not prove to be strong predictor of performance (correlation of -0.086). ^ These findings from the laboratory experiment and other lessons learned were incorporated to develop a quantitative measure, a tool (survey) to use to gather data for the variables in the measures, and a methodology to quantify coordination load of production business processes. The practicality of the methodology is demonstrated with an example.^

Organizational Effectiveness Along Life-Cycle Stages: A Comparison Of Wendy's And McDonald's

"Perceptions of Organizational Effectiveness over Organizational Life Cycles" written by Kim S. Cameron and David S. Whetten, posits a theory regarding organizational effectiveness criteria change as firms develop along the life cycle continuum. Induced from observations obtained from a simulation game, the Cameron and Whetten theory is applied in this article to two real organizations, Wendy's and McDonald's, with the intention of demonstrating that this theory is applicable in "real life" situations.

Cooperative or collaborative learning: Is there a difference in university students’ perceptions?

The hypothesis that the same educational objective, raised as cooperative or collaborative learning in university teaching does not affect students’ perceptions of the learning model, leads this study. It analyses the reflections of two students groups of engineering that shared the same educational goals implemented through two different methodological active learning strategies: Simulation as cooperative learning strategy and Problem-based Learning as a collaborative one. The different number of participants per group (eighty-five and sixty-five, respectively) as well as the use of two active learning strategies, either collaborative or cooperative, did not show differences in the results from a qualitative perspective.

A game theoretic simulation model for quality oriented timber supply to sawmills

Summary

Financial Policies and Dynamic Game Simulation in Poland and Hungary

Recently, steady economic growth rates have been kept in Poland and Hungary. Money supplies are growing rather rapidly in these economies. In large, exchange rates have trends of depreciation. Then, exports and prices show the steady growth rates. It can be thought that per capita GDPs are in the same level and development stages are similar in these two countries. It is assumed that these two economies have the same export market and export goods are competing in it. If one country has an expansion of monetary policy, price increase and interest rate decrease. Then, exchange rate decrease. Exports and GDP will increase through this phenomenon. At the same time, this expanded monetary policy affects another country through the trade. This mutual relationship between two countries can be expressed by the Nash-equilibrium in the Game theory. In this paper, macro-econometric models of Polish and Hungarian economies are built and the Nash- equilibrium is introduced into them.

3D simulation of complex shading affecting PV systems taking benefit from the power of graphics cards developed for the video game industry

Shading reduces the power output of a photovoltaic (PV) system. The design engineering of PV systems requires modeling and evaluating shading losses. Some PV systems are affected by complex shading scenes whose resulting PV energy losses are very difficult to evaluate with current modeling tools. Several specialized PV design and simulation software include the possibility to evaluate shading losses. They generally possess a Graphical User Interface (GUI) through which the user can draw a 3D shading scene, and then evaluate its corresponding PV energy losses. The complexity of the objects that these tools can handle is relatively limited. We have created a software solution, 3DPV, which allows evaluating the energy losses induced by complex 3D scenes on PV generators. The 3D objects can be imported from specialized 3D modeling software or from a 3D object library. The shadows cast by this 3D scene on the PV generator are then directly evaluated from the Graphics Processing Unit (GPU). Thanks to the recent development of GPUs for the video game industry, the shadows can be evaluated with a very high spatial resolution that reaches well beyond the PV cell level, in very short calculation times. A PV simulation model then translates the geometrical shading into PV energy output losses. 3DPV has been implemented using WebGL, which allows it to run directly from a Web browser, without requiring any local installation from the user. This also allows taken full benefits from the information already available from Internet, such as the 3D object libraries. This contribution describes, step by step, the method that allows 3DPV to evaluate the PV energy losses caused by complex shading. We then illustrate the results of this methodology to several application cases that are encountered in the world of PV systems design. Keywords: 3D, modeling, simulation, GPU, shading, losses, shadow mapping, solar, photovoltaic, PV, WebGL

Agent-based simulation of electronic marketplaces with decision support

This paper presents a Multi-Agent Market simulator designed for analyzing agent market strategies based on a complete understanding of buyer and seller behaviors, preference models and pricing algorithms, considering user risk preferences and game theory for scenario analysis. The system includes agents that are capable of improving their performance with their own experience, by adapting to the market conditions, and capable of considering other agents reactions.