Implementing an agent-based model with a spatial visual display in discrete-event simulation software

There has been an increasing interest in the use of agent-based simulation and some discussion of the relative merits of this approach as compared to discrete-event simulation. There are differing views on whether an agent-based simulation offers capabilities that discrete-event cannot provide or whether all agent-based applications can at least in theory be undertaken using a discrete-event approach. This paper presents a simple agent-based NetLogo model and corresponding discrete-event versions implemented in the widely used ARENA software. The two versions of the discrete-event model presented use a traditional process flow approach normally adopted in discrete-event simulation software and also an agent-based approach to the model build. In addition a real-time spatial visual display facility is provided using a spreadsheet platform controlled by VBA code embedded within the ARENA model. Initial findings from this investigation are that discrete-event simulation can indeed be used to implement agent-based models and with suitable integration elements such as VBA provide the spatial displays associated with agent-based software.

Market reform and state paternalism in Hungary: a path-dependent approach

Hungary is one of the worst-hit countries of the current financial crisis in Central and Eastern Europe. The deteriorating economic performance of the country is, however, not a recent phenomenon. A relatively high ratio of redistribution, a high and persistent public deficit and accelerated indebtedness characterised the country not just in the last couple of years but also well before the transformation, which also continued in the postsocialist years. The gradualist success of the country – which dates back to at least 1968 – in the field of liberalisation, marketisation and privatisation was accompanied by a constant overspending in the general government. The paper attempts to explore the reasons behind policymakers’ impotence to reform public finances. By providing a path-dependent explanation, it argues that both communist and postcommunist governments used the general budget as a buffer to compensate losers of economic reforms, especially microeconomic restructuring. The ever-widening circle of net benefiters of welfare provisions paid from the general budget, however, has made it simply unrealistic to implement sizeable fiscal adjustment, putting the country onto a deteriorating path of economic development.

Social change in Central and Eastern Europe: General trends and national patterns

The paper addresses five issue areas. First it describes the plurality of trajectories in central and eastern European transformations, offering a broad typology. Then it addresses the drift between acceptance of democracy and the market, owing to growing inequalities. Third, problems of poverty and exclusion are addressed. Fourth, it is addressed if any known model of redistribution emerged in the post-transition economies. Fifth, consequences of the populist turn in European policies are being analyzed. Influences of the EU practices will be dealt with and some preliminary conclusions drawn. These suggest a strong intertwining between social and economic performance that limit theoretically conceivable – neoliberal, social democratic, postmodern or conservative - policy choices.

Gazdasági kormányzás a gazdasági és monetáris unióban - a globális politika lehetetlen szentháromsága szemszögéből (Economic governance in the economic and monetary union – applying the trilemma of global politics)

Az Európai Unió a világgazdaság egyik legfontosabb integrációja. A benne megvalósuló gazdasági integráció szorossága megfelel annak a szintnek, amit Rodrik hiperglobalizációnak nevez. Az elmélet szerint a politika szintjén egyszerre nem megvalósítható a demokratikus politikai döntéshozatal, a teljes világgazdasági integráció, illetve a nemzetállam. A trilemma a globalizáció útjában álló intézményi különbségeken alapszik. Megoldása három módon lehetséges: a demokrácia kiiktatásával a megoldás az arany kényszerzubbony, ahol a piaci mechanizmusok veszik át az állami gazdaságpolitika szerepét; a globális kormányzás megvalósulása esetén a szuverén nemzetállamok tűnnek el a nemzetközi rendszerből; végül a Bretton Woods kompromisszum esetében a globalizáció útjába állítunk akadályokat. Írásunkban a modellt az európai integrációra, egészen pontosan a Gazdasági és Monetáris Unióra alkalmazzuk. Érvelésünk szerint, ha fent kívánjuk tartani az integráció szorosságát, erősíteni kell az integráció szintjén a gazdasági kormányzást, ami pedig csak a tagállami szuverenitás rovására mehet. Ez, mely a GMU esetében leginkább a fiskális föderáció erősítését jelenti ugyanakkor, megnövelve az integráció költségeit, egy többsebességes Európa kialakulása irányába hathat. _____ The European Union with its sophisticated institutional system is the most important regional integration on Earth. This tight form of economic integration converges to the level that Dani Rodrik calls hyperglobalization in his model, the political trilemma of globalisation. In this model Rodrik assumes that from the three desired element of world politics (deep economic integration, the nation state, and democratic politics) only two can be chosen. We can either choose deep integration and the nation state but then we have to abandon democracy; or we can choose deep integration and democracy, but then we have to forfeit the nation state; or we have to circumscribe globalisation to maintain democracy and the nation state. In our paper we develop the mentioned model and then we apply it to the case of the European integration. We argue that if we want to maintain the deep integration among member states in the EU we have to pass more and more functions of the nation states to the federation level. In case of the EMU that means that federal fiscal policy is needed which could lead to multi-speed Europe considering new member states reluctance to give up their specific institutions.

Patterns and Drivers of the Agri-Food Intra-Industry Trade of European Union Countries

This paper investigates the drivers of agri-food intra-industry trade (IIT) indices in the European Union (EU-27) member states during the period from 2000–2011. The increased proportion of IIT in matched two-way agri-food trade of the EU-27 member states is consistent with economic integration and economic growth. When export prices were at least 15% higher than the import prices, high-vertical IIT, increased for most member states. This finding suggests that quality improvements occurred when comparing agri-food exports to similar imports of agri-food products. The IIT indices for both horizontal and vertical IIT are positively associated with higher economic development levels, new EU membership and EU enlargement. Additionally, as higher levels of economic development decreases, the size of the economy and marginal IIT increases the effects of agri-food trade liberalization on the costs of the labor market adjustment. Understanding how improvements in agri-food trade quality impact agribusiness and managerial competitiveness reveal significant policy implications.

Empirical study of exchange rates in Brazil, Canada and the Caribbean

This dissertation examines the monetary models of exchange rate determination for Brazil, Canada, and two countries in the Caribbean, namely, the Dominican Republic and Jamaica. With the exception of Canada, the others adopted the floating regime during the past ten years.^ The empirical validity of four seminal models in exchange rate economics were determined. Three of these models were entirely classical (Bilson and Frenkel) or Keynesian (Dornbusch) in nature. The fourth model (Real Interest Differential Model) was a mixture of the two schools of economic theory.^ There is no clear empirical evidence of the validity of the monetary models. However, the signs of the coefficients of the nominal interest differential variable were as predicted by the Keynesian hypothesis in the case of Canada and as predicted by the Chicago theorists in the remaining countries. Moreover, in case of Brazil, due to hyperinflation, the exchange rate is heavily influenced by domestic money supply.^ I also tested the purchasing power parity (PPP) for this same set of countries. For both the monetary as well as the PPP hypothesis, I tested for co-integration and applied ordinary least squares estimation procedure. The error correction model was also used for the PPP model, to determine convergence to equilibrium.^ The validity of PPP is also questionable for my set of countries. Endogeinity among the regressors as well as the lack of proper price indices are the contributing factors. More importantly, Central Bank intervention negate rapid adjustment of price and exchange rates to their equilibrium value. However, its forecasting capability for the period 1993-1994 is superior compared to the monetary models in two of the four cases.^ I conclude that in spite of the questionable validity of these models, the monetary models give better results in the case of the "smaller" economies like the Dominican Republic and Jamaica where monetary influences swamp the other determinants of exchange rate. ^

Nonlinear dynamics and chaos simulation system analysis for improved design

Small errors proved catastrophic. Our purpose to remark that a very small cause which escapes our notice determined a considerable effect that we cannot fail to see, and then we say that the effect is due to chance. Small differences in the initial conditions produce very great ones in the final phenomena. A small error in the former will produce an enormous error in the latter. When dealing with any kind of electrical device specification, it is important to note that there exists a pair of test conditions that define a test: the forcing function and the limit. Forcing functions define the external operating constraints placed upon the device tested. The actual test defines how well the device responds to these constraints. Forcing inputs to threshold for example, represents the most difficult testing because this put those inputs as close as possible to the actual switching critical points and guarantees that the device will meet the Input-Output specifications. ^ Prediction becomes impossible by classical analytical analysis bounded by Newton and Euclides. We have found that non linear dynamics characteristics is the natural state of being in all circuits and devices. Opportunities exist for effective error detection in a nonlinear dynamics and chaos environment. ^ Nowadays there are a set of linear limits established around every aspect of a digital or analog circuits out of which devices are consider bad after failing the test. Deterministic chaos circuit is a fact not a possibility as it has been revived by our Ph.D. research. In practice for linear standard informational methodologies, this chaotic data product is usually undesirable and we are educated to be interested in obtaining a more regular stream of output data. ^ This Ph.D. research explored the possibilities of taking the foundation of a very well known simulation and modeling methodology, introducing nonlinear dynamics and chaos precepts, to produce a new error detector instrument able to put together streams of data scattered in space and time. Therefore, mastering deterministic chaos and changing the bad reputation of chaotic data as a potential risk for practical system status determination. ^

What secondary English to speakers of other languages (ESOL) teachers know about social and academic language and instructional strategies for limited English proficient students

The purpose of this study was to examine what secondary English to Speakers of Other Languages (ESOL) teachers understand about social and academic language, what instructional strategies they use for Limited English Proficient (LEP) students, and how these concepts are operationalized in their daily practice. ^ This was a mixed method study incorporating both quantitative and qualitative data collection and interpretation. Written questionnaires and individual interviews addressed the questions on teachers' definitions of social and academic language and their strategy use. Classroom observations provided verification of their definitions and their descriptions of instruction for academic language. ^ Findings indicated that teachers' definitions of social and academic language were still developing and that there were ambiguities in identifying examples of social and academic language. The use of graphic organizers or visual supports, groups or peer partners, role play or drama, and modeling were the strategies teachers consistently listed for beginner, intermediate, advanced and multiple level classes. Additionally, teachers' descriptions of their instruction were congruent with what was observed in their classroom practice. ^ It appeared that this population of secondary ESOL teachers was in the process of evolving their definitions of social and academic language and were at different stages in this evolution. Teachers' definitions of language influenced their instruction. Furthermore, those who had clear constructs of language were able to operationalize them in their classroom instruction. ^

Hyphenated cultures: Ethnicity and nation in Trinidad

This dissertation attempts to unravel why and how postcolonial Trinidad has displayed relative stability in spite of the presence of the factors that have produced conflict and instability in other postcolonial societies.^ Trinidad's distinctive social formation began in the colonial period with a unique politics of culture among the landowning European groups, Anglican English and French Creole. Contrary to the materialist assumption of landowners' class solidarity, the development of Trinidad's plantation economy into two crops, each controlled by a separate European ethno-religious faction, impeded the integration and subsequent ideological domination of European-Christians. Throughout the nineteenth century neither group dominated the other, nor did they fuse into a single ruling class. The dynamics between them both generated recurring conflict while simultaneously creating mechanisms that limited conflict. ^ Based on original in-depth fieldwork and historical analysis, the dissertation proceeds to demonstrate that Trinidad's unique intra-class conflict within the dominant European population has produced hyphenated, as opposed to hybridized cultural elements. Supplementing the historical analysis with empirical examinations of contemporary inter-religious rituals and post-colonial politics this dissertation argues that social integration is inseparable from the question of inter-cultural mixture or articulation. In Trinidad, however, the resulting combination of distinct cultural elements is neither a "plural society" (M.G. Smith 1965; Despres 1967) nor an integrated totality in the structural-functionalistic sense (R.T. Smith 1962; Braithwaite 1967). Moreover, Trinidad does not conform to the post-structural framework's depiction of the social linkage between power and culture. The concept of cultural hybridization is equally misleading in the case of Trinidad. The underlying assumption of a monolithic European population's cultural hegemony and post-structural analysis's almost exclusive focus on the inter -class politics of culture seriously misrepresent and misunderstand Trinidadian cultural and its associated social and political relations. The dissertation examines this reflexive influence of culture not as an instrument of the powerful few but as an autonomous force that reproduces social divisions, yet restrains conflict.^

Effective knowledge integration in emergency response organizations

Natural and man-made disasters have gained attention at all levels of policy-making in recent years. Emergency management tasks are inherently complex and unpredictable, and often require coordination among multiple organizations across different levels and locations. Effectively managing various knowledge areas and the organizations involved has become a critical emergency management success factor. However, there is a general lack of understanding about how to describe and assess the complex nature of emergency management tasks and how knowledge integration can help managers improve emergency management task performance. ^ The purpose of this exploratory research was first, to understand how emergency management operations are impacted by tasks that are complex and inter-organizational and second, to investigate how knowledge integration as a particular knowledge management strategy can improve the efficiency and effectiveness of the emergency tasks. Three types of specific knowledge were considered: context-specific, technology-specific, and context-and-technology-specific. ^ The research setting was the Miami-Dade Emergency Operations Center (EOC) and the study was based on the survey responses from the participants in past EOC activations related to their emergency tasks and knowledge areas. The data included task attributes related to complexity, knowledge area, knowledge integration, specificity of knowledge, and task performance. The data was analyzed using multiple linear regressions and path analyses, to (1) examine the relationships between task complexity, knowledge integration, and performance, (2) the moderating effects of each type of specific knowledge on the relationship between task complexity and performance, and (3) the mediating role of knowledge integration. ^ As per theory-based propositions, the results indicated that overall component complexity and interactive complexity tend to have a negative effect on task performance. But surprisingly, procedural rigidity tended to have a positive effect on performance in emergency management tasks. Also as per our expectation, knowledge integration had a positive relationship with task performance. Interestingly, the moderating effects of each type of specific knowledge on the relationship between task complexity and performance were varied and the extent of mediation of knowledge integration depended on the dimension of task complexity. ^

Graduate program culture and intention to persist: Working adults in cohort and non-cohort programs

Cohort programs have been instituted at many universities to accommodate the growing number of mature adult graduate students who pursue degrees while maintaining multiple commitments such as work and family. While it is estimated that as many as 40–60% of students who begin graduate study fail to complete degrees, it is thought that attrition may be even higher for this population of students. Yet, little is known about the impact of cohorts on the learning environment and whether cohort programs affect graduate student retention. Retention theory stresses the importance of the academic department, quality of faculty-student relationships and student involvement in the life of the academic community as critical determinants in students' decisions to persist to degree completion. However, students who are employed full-time typically spend little time on campus engaged in the learning environment. Using academic and social integration theory, this study examined the experiences of working adult graduate students enrolled in cohort (CEP) and non-cohort (non-CEP) programs and the influence of these experiences on intention to persist. The Graduate Program Context Questionnaire was administered to graduate students (N = 310) to examine measures of academic and social integration and intention to persist. Sample t tests and ANOVAs were conducted to determine whether differences in perceptions could be identified between cohort and non-cohort students. Multiple linear regression was used to identify variables that predict students' intention to persist. While there were many similarities, significant differences were found between CEP and non-CEP student groups on two measures. CEP students rated peer-student relationships higher and scored higher on the intention to persist measure than non-CEP students. The psychological integration measure, however, was the strongest predictor of intention to persist for both the CEP and non-CEP groups. This study supports the research literature which suggests that CEP programs encourage the development of peer-student relationships and promote students' commitment to persistence.

The relationship between a retention program and the persistence and graduation rates of first-generation low-income students at an urban, public university

The purpose of this study was to examine the relationship between participation in a retention program designed to promote academic and social integration and the persistence rates of first generation, low-income college students at an urban, public multiethnic university. Archival data were collected from the university’s Office of Institutional Research and the retention program office and included SAT/ACT scores, GPA, gender, ethnicity, and program participation data. A total of 292 first-generation, low-income students who were admitted to the university in the summer of 1999 were identified for the study. A group of 166 students were selected for the comparison group because they had not participated in the retention program; 126 students had participated in the retention program. ^ Three major research questions guided this study: (a) Are there differences in persistence rates and other academic characteristics of underprepared, low-income, first generation college students who participate and do not participate in the retention program?; (b) Does involvement in the retention program predict student persistence of first generation low-income, underprepared students?, and (c) Can predictors of GPA be identified for students in the retention program using program and descriptive variables? ^ A series of logistic regression analyses were conducted to assess the relationship between various retention services and the persistence and graduation rates of participants. The results showed that there were statistically significant relationships between participation and non-participation in the retention program and having higher GPAs and higher graduation and persistence rates. Of the four program features, participation in tutoring, workshops, and social events were found to be predictors of graduation. College GPA was also found to be a predictor of graduation for all students. The results also showed that women were more likely to graduate than men.^

The relationship between scaffolding metacognitive strategies identified through dialogue journals and second graders' reading comprehension, science achievement, and metacognition using expository text

Poor informational reading and writing skills in early grades and the need to provide students more experience with informational text have been identified by research as areas of concern. Wilkinson and Son (2011) support future research in dialogic approaches to investigate the impact dialogic teaching has on comprehension. This study (N = 39) examined the gains in reading comprehension, science achievement, and metacognitive functioning of individual second grade students interacting with instructors using dialogue journals alongside their textbook. The 38 week study consisted of two instructional phases, and three assessment points. After a period of oral metacognitive strategies, one class formed the treatment group (n=17), consisting of two teachers following the co-teaching method, and two classes formed the comparison group ( n=22). The dialogue journal intervention for the treatment group embraced the transactional theory of instruction through the use of dialogic interaction between teachers and students. Students took notes on the assigned lesson after an oral discussion. Teachers responded to students' entries with scaffolding using reading strategies (prior knowledge, skim, slow down, mental integration, and diagrams) modeled after Schraw's (1998) strategy evaluation matrix, to enhance students' comprehension. The comparison group utilized text-based, teacher-led whole group discussion. Data were collected using different measures: (a) Florida Assessments for Instruction in Reading (FAIR) Broad Diagnostic Inventory; (b) Scott Foresman end of chapter tests; (c) Metacomprehension Strategy Index (Schmitt, 1990); and (d) researcher-made metacognitive scaffolding rubric. Statistical analyses were performed using paired sample t-tests, regression analysis of covariance, and two way analysis of covariance. Findings from the study revealed that experimental participants performed significantly better on the linear combination of reading comprehension, science achievement, and metacognitive function, than their comparison group counterparts while controlling for pretest scores. Overall, results from the study established that teacher scaffolding using metacognitive strategies can potentially develop students' reading comprehension, science achievement, and metacognitive awareness. This suggests that early childhood students gain from the integration of reading and writing when using authentic materials (science textbooks) in science classrooms. A replication of this study with more students across more schools, and different grade levels would improve the generalizability of these results.

Radionuclides, Nd isotopes and biogenic Opal in Atlanic Ocean sediments

Reconstructing past modes of ocean circulation is an essential task in paleoclimatology and paleoceanography. To this end, we combine two sedimentary proxies, Nd isotopes (epsilon-Nd) and the 231Pa/230Th ratio, both of which are not directly involved in the global carbon cycle, but allow the reconstruction of water mass provenance and provide information about the past strength of overturning circulation, respectively. In this study, combined 231Pa/230Th and epsilon-Nd down-core profiles from six Atlantic Ocean sediment cores are presented. The data set is complemented by the two available combined data sets from the literature. From this we derive a comprehensive picture of spatial and temporal patterns and the dynamic changes of the Atlantic Meridional Overturning Circulation over the past ~25 ka. Our results provide evidence for a consistent pattern of glacial/stadial advances of Southern Sourced Water along with a northward circulation mode for all cores in the deeper (>3000 m) Atlantic. Results from shallower core sites support an active overturning cell of shoaled Northern Sourced Water during the LGM and the subsequent deglaciation. Furthermore, we report evidence for a short-lived period of intensified AMOC in the early Holocene.

Design, Fabrication, and Characterization of Carbon Nanotube Field Emission Devices for Advanced Applications

Carbon nanotubes (CNTs) have recently emerged as promising candidates for electron field emission (FE) cathodes in integrated FE devices. These nanostructured carbon materials possess exceptional properties and their synthesis can be thoroughly controlled. Their integration into advanced electronic devices, including not only FE cathodes, but sensors, energy storage devices, and circuit components, has seen rapid growth in recent years. The results of the studies presented here demonstrate that the CNT field emitter is an excellent candidate for next generation vacuum microelectronics and related electron emission devices in several advanced applications.

The work presented in this study addresses determining factors that currently confine the performance and application of CNT-FE devices. Characterization studies and improvements to the FE properties of CNTs, along with Micro-Electro-Mechanical Systems (MEMS) design and fabrication, were utilized in achieving these goals. Important performance limiting parameters, including emitter lifetime and failure from poor substrate adhesion, are examined. The compatibility and integration of CNT emitters with the governing MEMS substrate (i.e., polycrystalline silicon), and its impact on these performance limiting parameters, are reported. CNT growth mechanisms and kinetics were investigated and compared to silicon (100) to improve the design of CNT emitter integrated MEMS based electronic devices, specifically in vacuum microelectronic device (VMD) applications.

Improved growth allowed for design and development of novel cold-cathode FE devices utilizing CNT field emitters. A chemical ionization (CI) source based on a CNT-FE electron source was developed and evaluated in a commercial desktop mass spectrometer for explosives trace detection. This work demonstrated the first reported use of a CNT-based ion source capable of collecting CI mass spectra. The CNT-FE source demonstrated low power requirements, pulsing capabilities, and average lifetimes of over 320 hours when operated in constant emission mode under elevated pressures, without sacrificing performance. Additionally, a novel packaged ion source for miniature mass spectrometer applications using CNT emitters, a MEMS based Nier-type geometry, and a Low Temperature Cofired Ceramic (LTCC) 3D scaffold with integrated ion optics were developed and characterized. While previous research has shown other devices capable of collecting ion currents on chip, this LTCC packaged MEMS micro-ion source demonstrated improvements in energy and angular dispersion as well as the ability to direct the ions out of the packaged source and towards a mass analyzer. Simulations and experimental design, fabrication, and characterization were used to make these improvements.

Finally, novel CNT-FE devices were developed to investigate their potential to perform as active circuit elements in VMD circuits. Difficulty integrating devices at micron-scales has hindered the use of vacuum electronic devices in integrated circuits, despite the unique advantages they offer in select applications. Using a combination of particle trajectory simulation and experimental characterization, device performance in an integrated platform was investigated. Solutions to the difficulties in operating multiple devices in close proximity and enhancing electron transmission (i.e., reducing grid loss) are explored in detail. A systematic and iterative process was used to develop isolation structures that reduced crosstalk between neighboring devices from 15% on average, to nearly zero. Innovative geometries and a new operational mode reduced grid loss by nearly threefold, thereby improving transmission of the emitted cathode current to the anode from 25% in initial designs to 70% on average. These performance enhancements are important enablers for larger scale integration and for the realization of complex vacuum microelectronic circuits.