scholarly journals Nonrobustness of Dynamic Dual Models of the U.S. Dairy Industry

1989 ◽  
Vol 18 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Wayne H. Howard ◽  
C. Richard Shumway
Keyword(s):  
Technological Change ◽  
Functional Form ◽  
Dairy Industry ◽  
Dual Model ◽  
Competitive Firm ◽  
Functional Forms ◽  
Quality Indexes ◽  
Dual Models ◽  
The U.S

The robustness of dynamic dual model results across functional forms is examined for the U.S. dairy industry. Modified generalized Leontief (GL) and normalized quadratic (NQ) functional forms are compared by examining their consistency with properties of the competitive firm, estimated rates of adjustment for cows and labor, tests of technological change, and elasticities. Homogeneity and symmetry are maintained in both models. Convexity is not rejected by the GL and is not seriously violated by the NQ. Absence of technological change is rejected by both models, but quality indexes on labor and cows fully embody technological change occurring within labor and cows in the NQ but not in the GL. Policy-relevant elasticities differ greatly between the functional forms. Dynamic dual models are found to be non-robust in important ways to choice of functional form.

scholarly journals Functional Forms and Farm-Level Demand for Pecans by Variety

1991 ◽  
Vol 23 (2) ◽  
pp. 95-102 ◽  
Author(s):  
Albert A. Okunade ◽  
Mark J. Cochran
Keyword(s):  
Functional Form ◽  
Turning Points ◽  
Past Research ◽  
Nominal Data ◽  
Farm Level ◽  
Specific Analysis ◽  
Recent Developments ◽  
Functional Forms ◽  
Price Flexibility ◽  
The U.S

AbstractRecent developments in the U.S. pecan industry appear to limit the utility of past research. The importance of pecan variety has emerged as an issue which could alter past results. The linear and double-log models previously fitted to all-pecans (averaged) data may be too restrictive and hence, are less useful for variety-specific analysis. Past research also analyzed price turning points using nominal data. This study investigated functional form and data-averaging problems by fitting separate flexible Box-Cox price-dependent models for all-pecans and each variety of pecans (1970/71-1988/89 deflated data). Results indicate: other nuts substitute for different pecan varieties, estimated all-pecans price flexibility is biased and clouds variety-specific flexibilities, and restrictive functional forms are inappropriate.

Temporally-ordered CDW creep in pure and doped NbSe3

2002 ◽  
Vol 12 (9) ◽  
pp. 315-315
Author(s):  
K. Cicak ◽  
K. O'Neill ◽  
R. E. Thorne
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Driving Force ◽  
Functional Form ◽  
Collective Motion ◽  
Density Wave ◽  
Velocity Versus ◽  
Initial Work ◽  
Functional Forms ◽  
Creep Velocity

Below T=40 K, charge-density wave (CDW) transport in NbSe3 is characterized by two well-defined driving force thresholds ET and ET*. Between these thresholds the CDW moves extremely slowly with creep-like temperature and driving force dependencies. At the same time, the CDW exhibits coherent oscillations with a frequency proportional to the CDW current and having very narrow spectral widths, suggesting that the collective motion is temporally ordered. We have extended our initial work to doped crystals containing isoelectronic (Ta) and nonisoelectronic (Ti) impurities, and to crystals of different thicknesses. These experiments show that the qualitative features are extremely robust, and that the functional form of the creep velocity versus driving force and temperature is consistent across all samples for currents ranging over five orders of magnitude. The temperature dependence is consistent with processes having an energy comparable to the CDW gap, but the field and impurity dependencies are inconsistent with all predicted functional forms for creep in CDWs and related systems, and with our earlier picture of amplitude collapse at each impurity. We compare our results to measurements of creep-like behavior in other CDW and SDW systems, and discuss possible mechanisms.

scholarly journals Study on a Twice Transfer Alignment Based on Dual Model

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Shuai Chen ◽  
Runwu Zhong ◽  
Xiaohui Liu ◽  
Ahmed Alsaedi
Keyword(s):  
Kalman Filter ◽  
Convergence Time ◽  
Alignment Algorithm ◽  
Dual Model ◽  
Matching Method ◽  
Error Models ◽  
Transfer Alignment ◽  
Nonlinear Error ◽  
Dual Models ◽  
Rapid Transfer

This paper proposes a twice rapid transfer alignment algorithm based on dual models in order to solve the problems such as long convergence time, poor accuracy, and heavy computation burden resulting from the traditional nonlinear error models. The quaternion matching method based on quaternion error model along with the extended Kalman filter (EKF) is applied to deal with the large misalignment in the first phase. Then in the second transfer alignment phase, velocity plus attitude matching method as well as classical Kalman filter is adopted. The simulation and the results of vehicle tests demonstrate that this method combines the advantages of both nonlinear and linear error models with the guarantee of accuracy and fastness.

Technological Change, Market Decline, and Industrial Relations in the U.S. Steel Industry

1987 ◽  
pp. 229-245 ◽  
Author(s):  
Dennis A. Ahlburg ◽  
Ann E. Carey ◽  
Bruce A. Lundgren ◽  
Sandra L. Barrett ◽  
Lawrence D. Anderson
Keyword(s):  
Technological Change ◽  
Steel Industry ◽  
Industrial Relations ◽  
The U.S

scholarly journals Skill-Biased Technological Change and Inequality in the U.S.

2020 ◽  
pp. 91-107
Author(s):  
Ana Ferreira
Keyword(s):  
Income Inequality ◽  
Technological Change ◽  
Incomplete Markets ◽  
Gini Coefficient ◽  
Income Tax ◽  
Overlapping Generations ◽  
Overlapping Generations Model ◽  
Biased Technological Change ◽  
Household Heterogeneity ◽  
The U.S

Since the 1980s, income inequality has increased markedly and has reached the highest level ever since it started being recorded in the U.S. This paper uses an overlapping generations model with incomplete markets that allows for household heterogeneity that is calibrated to match the U.S. economy with the purpose to study how skill-biased technological change (SBTC) and changes in taxation quantitatively account for the increase in inequality from 1980 to 2010. We find that SBTC and taxation decrease account for 48% of the total increase in the income Gini coefficient. In particular, we conclude that SBTC alone accounted for 42% of the overall increase in income inequality, while changes in the progressivity of the income tax schedule alone accounted for 5.7%.

scholarly journals A unifying theory to describe transmembrane transport derived from thermodynamic principles

2015 ◽  
Author(s):  
Marco A Herrera-Valdez
Keyword(s):  
Transmembrane Potential ◽  
Functional Form ◽  
Molecular Transport ◽  
Planck Equation ◽  
Transmembrane Transport ◽  
Membrane Excitability ◽  
Nonlinear Functions ◽  
Functional Forms ◽  
Membrane Spanning ◽  
Transmembrane Currents

Herrera-Valdez. A unifying theory of physiological transmembrane transport Cellular homeostasis involves transmembrane molecular transport that is, in turn, mediated by proteins that enable molecular transport along, or against the (electro) chemical gradient of the molecules being transported. Transmembrane transport has been modelled in many studies using many functional forms that were not always derived from the same assumptions. A generic formulation that describes transmembrane fluxes regardless of whether they are mediated by carrier proteins or by open channels is presented here. The functional form of the flux was obtained from basic thermodynamic principles. Further, taking a slightly different approach, the same generic formulation mentioned above can also be obtained from the Nernst-Planck equation for the case of channel- mediated electrodiffusion. The generic formulation can be regarded as the product of an amplitude term and a driving force term, both nonlinear functions of the transmembrane concentrations of the molecules and possibly the transmembrane potential. The former captures the characteristics of the membrane-spanning protein mediating the transport and the latter is a non-linear function of the transmembrane concentrations of the ions. The generic formulation explicitly shows that the basal rate at which ions cross the membrane is the main difference between currents mediated by pumps and channels. Electrogenic transmembrane fluxes can be converted to currents to construct models of membrane excitability in which all the transmembrane currents have the same functional form. The applicability of the generic derivations presented here is illustrated with models of excitability for neurones and pacemaker cardiocytes.

Gunfire at Sea: A Case Study of Innovation

2016 ◽  
Author(s):  
Elting E. Morison
Keyword(s):  
Technological Change ◽  
Resistance To Change ◽  
Personal Identification ◽  
Technological Changes ◽  
Technical Aspects ◽  
Powerful Explanation ◽  
The U.S

This chapter presents a case study of innovation: the introduction of continuous-aim firing in the U.S. Navy. It first provides a background on the technical aspects of gunfire at sea prior to the introduction of continuous-aim firing, first devised by an English officer, Admiral Sir Percy Scott, in 1898. It then considers the benefits brought by Scott's invention, in particular in terms of improving gunnery accuracy in the U.S. Navy. It also discusses Washington's responses to William S. Sims's recommendations for adopting continuous-aim firing in the U.S. Navy, citing the reasons for what must be considered the weird response to the proposed technological change. It shows that personal identification with a concept, a convention, or an attitude appears to be a powerful explanation for resistance to change. The chapter suggests an “adaptive society” in which humans adapt to their own technological changes.

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