A Sinusoidal Current Driver With an Extended Frequency Range and Multifrequency Operation for Bioimpedance Applications

This paper describes an alternative sinusoidal current driver suitable for bioimpedance applications where high frequency operation is required. The circuit is based on a transconductor and provides current outputs with low phase error for frequencies around its pole frequency. This extends the upper frequency operational limit of the current driver. Multifrequency currents can be generated where each individual frequency is phase corrected. Analysis of the circuit is presented together with simulation and experimental results which demonstrate the proof of concept for both single and dual frequency current drivers. Measurements on a discrete test version of the circuit demonstrate a phase reduction from 25 ^{\circ} to 4 ^{\circ} at 3 MHz for 2 mAp-p output current. The output impedance of the current driver is essentially constant at about 1.1 M \Omega over a frequency range of 100 kHz to 5 MHz due to the introduction of the phase compensation. The compensation provides a bandwidth increase of a factor of about six for a residual phase delay of 4 ^{\circ

Capabilities and Governance the Rebirth of Production in the Theory of Economic Organization

We argue that since Coase’s seminal 1937 paper on “The Nature of the Firm,” there has been an odd and unjustified separation between price theory and the economics of organization. For example, matters of production has been the domain of the former exclusively. However, a new approach to economic organization, here called “the capabilities approach,” that places production center-stage in the explanation of economic organization, is now emerging. We discuss the sources of this approach and its relation to the mainstream economics of organization.Capability, Theory of the Firm, Price Theory

Innovation processes and industrial districts

In this survey, we examine the operations of innovation processes within industrial districts by exploring the ways in which differentiation, specialization, and integration affect the generation, diffusion, and use of new knowledge in such districts. We begin with an analysis of the importance of the division of labour and then investigate the effects of social embeddedness on innovation. We also consider the effect of forms of organization within industrial districts at various stages of product and process life, and we examine the negative aspects of embeddedness for innovation. We conclude with a discussion of the possible consequences of new information and communications technologies on innovation in industrial districts

Massive scalar states localized on a de Sitter brane

We consider a brane scenario with a massive scalar field in the five-dimensional bulk. We study the scalar states that are localized on the brane, which is assumed to be de Sitter. These localized scalar modes are massive in general, their effective four-dimensional mass depending on the mass of the five-dimensional scalar field, on the Hubble parameter in the brane and on the coupling between the brane tension and the bulk scalar field. We then introduce a purely four-dimensional approach based on an effective potential for the projection of the scalar field in the brane, and discuss its regime of validity. Finally, we explore the quasi-localized scalar states, which have a non-zero width that quantifies their probability of tunneling from the brane into the bulk.Comment: 14 pages; 5 figure

The changing tide: Federal support of civilian-sector R and D

The involvement of the Federal government in civilian sector research and development is discussed. Relevant policies are put in an historical perspective. The roles played by industrial research and public funding are reveiwed. Government support of basic an generic research, clientele-oriented applied research, and research with commercial ends is studied. Procurement, anti-trust, and patent policies, all of which affect the climate for private research and development, are examined

The Vanishing Hand: the Changing Dynamics of Industrial Capitalism

In a series of classic works, most notably The Visible Hand (1977) and Scale and Scope (1990), Alfred Chandler focused the spotlight on the large, vertically integrated modern corporation. Put simply, Chandler’s argument is this. In the late nineteenth century, the large vertically integrated corporation emerged in the United States to replace what had been a fragmented and localized structure of production and distribution. The driving force behind this transformation was increased population and higher per-capita income, combined with lowered transportation and communications costs made possible by the spread of the railroad and telegraph. Adam Smith had predicted an increasingly fine division of labor as the response to a growing extent of the market; and, although he was actually quite vague on the organizational consequences of the division of labor, Smith was clear in his insistence on the power of the invisible hand of markets to coordinate economic activity. Chandler’s account challenges this prediction: internal or managerial coordination became necessary to coordinate the “new economy” of the late nineteenth and early twentieth centuries, and the visible hand of managerial coordination replaced the invisible hand of the market. Many would argue that the late twentieth (and now early twenty-first) centuries are witnessing a revolution at least as important as the one Chandler described. Population and income are again a driving force, but the railroad and telegraph have been replaced by the computer, telecommunications technology, and the Internet. In this epoch, Smithian forces may be outpacing Chandlerian ones. Management retains important functions, of course, including some of the same ones Chandler described. But as the central mechanism for coordinating high-throughput production, the visible hand — many would argue — is fading into a ghostly translucence. This paper is a preliminary attempt to explain why this is so — to provide some theoretical insight into the organizational structure of the new economy. The basic argument — the vanishing-hand hypothesis — is as follows. Driven by increases in population and income and by the reduction of technological and legal barriers to trade, the Smithian process of the division of labor always tends to lead to finer specialization of function and increased coordination through markets. But the components of that process —technology, organization, and institutions — change at different rates. The managerial revolution Chandler chronicles was the result of such an imbalance, in this case between the coordination needs of high-throughput technologies and the abilities of contemporary markets and contemporary technologies of coordination to meet those needs. With further growth in the extent of the market and improvements in the technology of coordination, the central management of vertically integrated production stages is increasingly succumbing to the forces of specialization.Managerial Revolution New Economy Vertical Integration Outsourcing Subcontracting Corporation buffering

Dynamical Evolution of the Extra Dimension in Brane Cosmology

The evolution of the extra dimension is investigated in the context of brane world cosmology. New cosmological solutions are found. In particular, solutions in the form of waves travelling along the extra dimension are identified.Comment: Latex file, 10 page

Knowledge and Meliorism in the Evolutionary Theory of F. A. Hayek

No abstract available

Of Hackers and Hairdressers: Modularity and the Organizational Economics of Open-source Collaboration

By employing modularity theory, we study the general phenomenon of open-source collaboration, which includes, e.g., collective invention and open science besides open-source software production. We focus on how open-source collaboration coordinates the division of labor. We find that open-source collaboration is an organizational form based on the exchange of effort rather than of products where suppliers of effort self-identify like suppliers of products in a market rather than accepting assignments like employees in a firm. Our finding suggests that actual open-source software (and other) projects are neither bazaars nor cathedrals, but hybrids manifesting both voluntary production and conscious planning

Primordial gravitational waves in inflationary braneworld

We study primordial gravitational waves from inflation in Randall-Sundrum braneworld model. The effect of small change of the Hubble parameter during inflation is investigated using a toy model given by connecting two de Sitter branes. We analyze the power spectrum of final zero-mode gravitons, which is generated from the vacuum fluctuations of both initial Kaluza-Klein modes and zero-mode. The amplitude of fluctuations is confirmed to agree with the four-dimensional one at low energies, whereas it is enhanced due to the normalization factor of zero-mode at high energies. We show that the five-dimensional spectrum can be well approximated by applying a simple mapping to the four-dimensional fluctuation amplitude.Comment: 16 pages, 4 figures, typos correcte