Color screening in a constituent quark model of hadronic matter

The effect of color screening on the formation of a heavy quark-antiquark ($Q\bar{Q}$) bound state--such as the $J/\psi$ meson--is studied using a constituent-quark model. The response of the nuclear medium to the addition of two color charges is simulated directly in terms of its quark constituents via a string-flip potential that allows for quark confinement within hadrons yet enables the hadrons to separate without generating unphysical long-range forces. Medium modifications to the properties of the heavy meson, such as its energy and its mean-square radius, are extracted by solving Schr\"odinger's equation for the $Q\bar{Q}$ pair in the presence of a (screened) density-dependent potential. The density dependence of the heavy-quark potential is in qualitative agreement with earlier studies of its temperature dependence extracted from lattice calculations at finite temperature. In the present model it is confirmed that abrupt changes in the properties of the $J/\psi$-meson in the hadronic medium ({\it plasma}), correlate strongly with the deconfining phase transition.Comment: 7 pages, 3 figures, submitted to PRC for publication, uses revtex

GDP Data Revisions and Forward-Looking Monetary Policy in Switzerland

This paper analyzes forward-looking rules for Swiss monetary policy in a small structural VAR model consisting of four variables taking into account data revisions for GDP. First, the paper develops an analytical method to analyze the effect of data revision errors in GDP on the ex ante or conditional inflation-output-growth volatility trade-off and applies it to Swiss data. Second, the effects of different targets in a forward-looking monetary policy on ex post or unconditional volatility of inflation and output growth is explored by a simulation exercise. In general, the results obtained suggest that focusing monetary policy on GDP growth instead on inflation may lead to an inefficient policy with both increased medium term inflation and GDP growth volatility in the presence of GDP data revisions.Structural VAR, forward-looking monetary policy, efficiency frontier, GDP data revisions

The Analysis of Forward-Looking Monetary Policy in a SVAR Framework

This paper analyzes forward-looking monetary policy rules in structural VAR’s. First, an approach for modeling a monetary policy which aims at a strict medium term inflation or output growth target is developed. Second, the ex ante inflation-output-growth volatility trade-off for a forward-looking policy aiming at a convex combination these strategies is derived. Finally, an illustration of our approach using Swiss data is given.Structural VAR, forward-looking monetary policy, efficiency frontier

A cross impact methodology for the assessment of US telecommunications system with application to fiber optics development: Executive summary

A cross impact model of the U.S. telecommunications system was developed. For this model, it was necessary to prepare forecasts of the major segments of the telecommunications system, such as satellites, telephone, TV, CATV, radio broadcasting, etc. In addition, forecasts were prepared of the traffic generated by a variety of new or expanded services, such as electronic check clearing and point of sale electronic funds transfer. Finally, the interactions among the forecasts were estimated (the cross impacts). Both the forecasts and the cross impacts were used as inputs to the cross impact model, which could then be used to stimulate the future growth of the entire U.S. telecommunications system. By varying the inputs, technology changes or policy decisions with regard to any segment of the system could be evaluated in the context of the remainder of the system. To illustrate the operation of the model, a specific study was made of the deployment of fiber optics, throughout the telecommunications system

Measurement errors in GDP and forward-looking monetary policy: The Swiss case

This paper analyzes forward-looking rules for Swiss monetary policy in a small structural VAR consisting of four variables. First, the paper looks at the ex ante inflation-output-growth volatility trade-off for a forward-looking policy aiming at a convex combination of a strict inflation and output growth targeting rule implied by this SVAR model. Thereby the paper introduces a new analytical method. Second, the paper considers the effect of measurement errors in GDP on this inflation-output-growth volatility trade-off. Third, the paper works at the impact of changing beliefs about the potential growth rate on the variability of output growth and inflation. Finally the effects of different targets in a forward-looking monetary policy on ex post or unconditional volatility of inflation and output growth is explored by a simulation exercise. --Structural VAR,forward-looking monetary policy,efficiency frontier,GDP measurement errors

A cross impact methodology for the assessment of US telecommunications system with application to fiber optics development, volume 2

The appendices for the cross impact methodology are presented. These include: user's guide, telecommunication events, cross impacts, projection of historical trends, and projection of trends in satellite communications

A cross impact methodology for the assessment of US telecommunications system with application to fiber optics development, volume 1

A cross impact model of the U.S. telecommunications system was developed. It was necessary to prepare forecasts of the major segments of the telecommunications system, such as satellites, telephone, TV, CATV, radio broadcasting, etc. In addition, forecasts were prepared of the traffic generated by a variety of new or expanded services, such as electronic check clearing and point of sale electronic funds transfer. Finally, the interactions among the forecasts were estimated (the cross impact). Both the forecasts and the cross impacts were used as inputs to the cross impact model, which could then be used to stimulate the future growth of the entire U.S. telecommunications system. By varying the inputs, technology changes or policy decisions with regard to any segment of the system could be evaluated in the context of the remainder of the system. To illustrate the operation of the model, a specific study was made of the deployment of fiber optics throughout the telecommunications system

Customized Software in Distributed Embedded Systems: ISOBUS and the Coming Revolution in Agriculture

The electrification of agricultural equipment has been evolving for many years and in some ways is lagging behind other industries. However this strategy of following the lead of other industries now offers Ag the opportunity to move forward at a revolutionary pace. Network standards defined by the Society of Automotive Engineers (SAE) and the International Organization for Standardization (ISO) committees are the basis for defining a rulebook for this industrystandardizing worldwide electronics interoperability. ISOBUS (ISO 11783) which defines a physical standard between tractors and implements will be an important enabler for most new product definitions. The foundation of this coming revolution will be provided through software. This paper outlines the electronics hardware and software architecture for off-road vehicles that allows for implementation of customized machine control features. There are several key areas discussed. The first enabler for this revolution is a software development and delivery system that defines a design methodology for creating and delivering software modules for a distributed set of controllers. This design methodology presents two advantages that today’s modern electronic technologies can deliver: 1) Customization with commodity hardware and 2) Service without replacing hardware parts anywhere in the world. The second enabler for this machine revolution is an ‘agile’ process to develop the software. Many product ideas are being valuated through a trial and error and continuous improvement process. Software will play an important enabler for these product definitions. A comparison between the worldwide trend for software processes, the Capability Maturity Model (CMM), and what type of process would fit the offroad industry is based around the maturity of the new product ideas. The strong supply chain link between dealers and customers for off-road machines, coupled with the emerging awareness of electronic functions and controls, sets a basis for a specialized software development process. An important enabler for this ‘agile’ process is the re-use of code and incremental testing with reviews. The history of the off-road machine business has been based on proven designs and long times between model updates. However, the worldwide adoption of the ISOBUS standard is poised to change this history. ISOBUS is not only establishing an open system for interoperability, it is establishing a sequence of features for diagnostics, sequenced operations, and information management. As customers discover these capabilities, they will expect them to be further advanced and customized for their specific needs. This requires adding agility into the proven durable processes so that manufacturers can respond faster to these growing needs. Electronics, and especially well-planned software systems, offer an agile technology for meeting this coming need. This paper presents the benchmarking of various embedded software development projects relating project content, project rigor, and quality. From this, insights into maintaining quality are gained in order to include agility into a durable development project. Also, risk and rewards of leveraging low cost country software development skills are addressed to stretch resources or even develop common resources for software systems

Extinctions and Correlations for Uniformly Discrete Point Processes with Pure Point Dynamical Spectra

The paper investigates how correlations can completely specify a uniformly discrete point process. The setting is that of uniformly discrete point sets in real space for which the corresponding dynamical hull is ergodic. The first result is that all of the essential physical information in such a system is derivable from its $n$-point correlations, $n= 2, 3, >...$. If the system is pure point diffractive an upper bound on the number of correlations required can be derived from the cycle structure of a graph formed from the dynamical and Bragg spectra. In particular, if the diffraction has no extinctions, then the 2 and 3 point correlations contain all the relevant information.Comment: 16 page