Root locii for systems defined on Hilbert spaces

The root locus is an important tool for analysing the stability and time constants of linear finite-dimensional systems as a parameter, often the gain, is varied. However, many systems are modelled by partial differential equations or delay equations. These systems evolve on an infinite-dimensional space and their transfer functions are not rational. In this paper a rigorous definition of the root locus for infinite-dimensional systems is given and it is shown that the root locus is well-defined for a large class of infinite-dimensional systems. As for finite-dimensional systems, any limit point of a branch of the root locus is a zero. However, the asymptotic behaviour can be quite different from that for finite-dimensional systems. This point is illustrated with a number of examples. It is shown that the familiar pole-zero interlacing property for collocated systems with a Hermitian state matrix extends to infinite-dimensional systems with self-adjoint generator. This interlacing property is also shown to hold for collocated systems with a skew-adjoint generator

C0C_0-semigroups for hyperbolic partial differential equations on a one-dimensional spatial domain

Hyperbolic partial differential equations on a one-dimensional spatial domain are studied. This class of systems includes models of beams and waves as well as the transport equation and networks of non-homogeneous transmission lines. The main result of this paper is a simple test for $C_0$-semigroup generation in terms of the boundary conditions. The result is illustrated with several examples

The International Monetary System: Developments and Prospects

This paper addresses several fundamental issues raised by recent developments in the world economy and considers their implications for the design and functioning of the international monetary system. We do not make any proposals. The four issues examined in the paper are: (1) Can the exchange rate regime do much to discipline fiscal policy?; (2) What are the extent and costs of reduced monetary independence under greater fixity of exchange rates?; (3) How can the equilibrium exchange rate best be determined?; (4) Does a well functioning international monetary system require a clearly defined set of rules, an acknowledged leader, and an explicit anchor?

A Guide to Target Zones

This paper identifies key issues surrounding the advisability and practicality of adopting "target zones" for the exchange rates of major currencies. Pour fundamental questions concerning the definition of and the rationale for target zones are addressed: first, what is generally meant by a "target zone" approach to exchange rate management and how can "hard" and "soft" versions of this approach be defined; second, what are the perceived deficiencies in the existing exchange rate system of managed floating which motivate the call for the adoption of target zones; third, how might target zones remedy these deficiencies; and fourth, what factors are behind much of the skepticism over and opposition to target zones? In addition, the paper deals with a series of operational questions of a more technical nature that weigh heavily on the practicality of implementing a target zone approach. The issues discussed include the following: how would the target zones be calculated; what currencies would be included in the system of target zones; how wide should the target zones be and how frequently should they be revised; and what policy instruments would be employed to keep actual exchange rates within the target zones, and with what consequences for other policy objectives? The purpose of the paper is not to make the case either for or against the adoption of target zones. Rather, the intention is to raise and discuss factors that should be considered in any serious discussion of the topic.

Zero Dynamics for Port-Hamiltonian Systems

The zero dynamics of infinite-dimensional systems can be difficult to characterize. The zero dynamics of boundary control systems are particularly problematic. In this paper the zero dynamics of port-Hamiltonian systems are studied. A complete characterization of the zero dynamics for a port-Hamiltonian systems with invertible feedthrough as another port-Hamiltonian system on the same state space is given. It is shown that the zero dynamics for any port-Hamiltonian system with commensurate wave speeds are well-defined, and are also a port-Hamiltonian system. Examples include wave equations with uniform wave speed on a network. A constructive procedure for calculation of the zero dynamics, that can be used for very large system order, is provided.Comment: 17 page

Examining Employee Engagement to Predict Retention Rates

The 21st Century brings many changes to the workplace. Organizations today are starting to focus more energy on engaging and retaining employees. An interdisciplinary approach through a secondary analysis was used to understand the correlation between employee engagements; retention and the ways engagement surveys can be administered. The findings suggest a correlation between employee engagement and retention rates. This study also discusses engagement survey format. However, of the study show engagement is not segment specific but rather it is company specific. In addition, this study does not examine ways organizations communicate the findings of engagement surveys to employees

Recessions in Higher Education: A Study of Faculty Sensitivities to Changes in Funding Vis-à-vis Periods of Recession

This paper analyzes the degree to which faculty at public universities are further impacted by the financial difficulties brought about by recessions than their private counterpart and how that trend has changed over time. Contracting state budgets for public universities and dips in endowment revenue for private universities compel these institutions to cut back on large-scale spending, such as faculty, or garner the missing revenue from other sources, such as raising the cost of tuition. We consider the number of faculty and their respective salaries as our outcomes of interest. We hypothesized that public universities would fare worse during economic downturns than private universities primarily due to specific vulnerabilities in their funding relative to private universities. Using university-level fixed effects, we consider university faculty dis-aggregated by rank, sex, and salary. This study contributes to some existing literature on recessions and their relationship to universities specifically by addressing the aspects relating to faculty counts and earnings, and covering more recessions. It considers historical data from 1983 to 2014, capturing the four previous recessions. We find that while in some instances, faculty at public higher education institutions are more vulnerable to the adverse effects of a recession, it is not always the case

Listening Awry: Lacan and the Electric Guitar at the Intersection of Music, Technology, and Identity

Contemporary positions on technology tend to emphasize that its import lies in its appropriation by a given social actor (group or individual), by how it is used. This paper does not categorically deny that such is often the case, but suggests that its inversion is widely overlooked. Overlooked, because much like the skull in Holbein’s The Ambassadors, evidence of technology’s active effect on the user is distorted until viewed from a particular vantage point. This paper takes Lacanian psychoanalysis as its vantage point and the musical technoculture of the electric guitarist as its object, revealing in the electric guitarist’s pursuit of identity through timbre that technology functions as the object-cause of desire, the objet petit a. Evidence of such an anamorphosis certainly supports the need for psychoanalysis in a critical musicology, but the larger implication is for thinkers of all disciplinary stripes to give technology a second look (or in this case a second listen) in order to move beyond the usual determinist, voluntarist, or even Luddite approaches