193,287 research outputs found
Spatial Chow-Lin Methods for Data Completion in Econometric Flow Models
No full textFlow data across regions can be modeled by spatial econometric models, see LeSage and Pace (2009). Recently, regional studies became interested in the aggregation and disaggregation of flow models, because trade data cannot be obtained at a disaggregated level but data are published on an aggregate level. Furthermore, missing data in disaggregated flow models occur quite often since detailed measurements are often not possible at all observation points in time and space. In this paper we develop classical and Bayesian methods to complete flow data. The Chow and Lin (1971) method was developed for completing disaggregated incomplete time series data. We will extend this method in a general framework to spatially correlated flow data using the cross-sectional Chow-Lin method of Polasek et al. (2009). The missing disaggregated data can be obtained either by feasible GLS prediction or by a Bayesian (posterior) predictive density.Missing values in spatial econometrics, MCMC, non-spatial Chow-Lin (CL) and spatial Chow-Lin (SCL) methods, spatial internal flow (SIF) models, origin and destination (OD) data
Chow Theorem and structure of Carnot-Caratheodory balls
No full textopenThis thesis is meant to be a study on the role of the C-C metrics in the Chow theorem and on the structure of C-C balls.
It opens with a section in which we give the definitions of vector field and bracket and we state the properties of the latter.
Then we give the definition of the most important object of this work: the Carnot-Caratheodory metrics and we state some basic propositions on its behavior, hinting also to some metrics which are equivalent to it.
We now proceed giving preliminary notions about exponential maps on a compact set of R^n, we state the Campbell-Hausdorff formula for two smooth vector fields and we introduce an object defined as a composition of exponentials E(J,t).
We finally state the Chow theorem for m smooth vector fields in R^n satisfying the Chow-Hoermander condition. We prove it using the Campbell-Hausdorff formula and defining through E(J,t) n approximated exponential maps whose composition provides us with a local diffeomorphism.
This theorem is particularly important because it tells us that under Chow-Hoermander condition we can regain directions that would be otherwise prohibited.
We introduce the doubling metric spaces and in particular we state a theorem on the structure of C-C balls: the Nagel-Stein-Wainger theorem, which provides us with the size of the C-C balls and tells us they are represented as the image of rectangles under the exponential map.
At last, we close this work with a variant of the structure theorem.This thesis is meant to be a study on the role of the C-C metrics in the Chow theorem and on the structure of C-C balls.
It opens with a section in which we give the definitions of vector field and bracket and we state the properties of the latter.
Then we give the definition of the most important object of this work: the Carnot-Caratheodory metrics and we state some basic propositions on its behavior, hinting also to some metrics which are equivalent to it.
We now proceed giving preliminary notions about exponential maps on a compact set of R^n, we state the Campbell-Hausdorff formula for two smooth vector fields and we introduce an object defined as a composition of exponentials E(J,t).
We finally state the Chow theorem for m smooth vector fields in R^n satisfying the Chow-Hoermander condition. We prove it using the Campbell-Hausdorff formula and defining through E(J,t) n approximated exponential maps whose composition provides us with a local diffeomorphism.
This theorem is particularly important because it tells us that under Chow-Hoermander condition we can regain directions that would be otherwise prohibited.
We introduce the doubling metric spaces and in particular we state a theorem on the structure of C-C balls: the Nagel-Stein-Wainger theorem, which provides us with the size of the C-C balls and tells us they are represented as the image of rectangles under the exponential map.
At last, we close this work with a variant of the structure theorem
SPATIAL CHOW-LIN METHODS: BAYESIAN AND ML FORECAST COMPARISONS
No full textCompleting data that are collected in disaggregated and heterogeneous spatial units is a quite frequent problem in spatial analyses of regional data. Chow and Lin (1971) (CL) were the rst to develop a uni ed framework for the three problems (interpolation, extrapolation and distribution) of predicting disaggregated times series by so-called indicator series. This paper develops a spatial CL procedure for disaggregating cross-sectional spatial data and compares the Maximum Likelihood and Bayesian spatial CL forecasts with the naive pro rata error distribution. We outline the error covariance structure in a spatial context, derive the BLUE for the ML estimator and the Bayesian estimation procedure by MCMC. Finally we
apply the procedure to European regional GDP data and discuss the disaggregation assumptions. For the evaluation of the spatial Chow-Lin procedure we assume that only NUTS 1 GDP is known and predict it at NUTS 2 by using employment and spatial information available at NUTS 2. The spatial neighborhood is de ned by the inverse travel time by car in minutes. Finally, we present the forecast accuracy criteria comparing the predicted values with the actual observations.
Important Lessons from Studying the Chinese Economy
No full textIn 1979 the United States and China established normal diplomatic relations, allowing me to visit China and study the Chinese economy. After doing so for thirty years since and advising the government of Taiwan in the 1960s and the 1970s and the government of the People’s Republic of China in the 1980s and the 1990s this is an opportune moment for me to summarize the important lessons that I have learned. The lessons will be summarized in four parts: on economic science, on formulating economic policy and providing economic advice, on the special characteristics of the Chinese economy and on the experience of China’s economic reform. At the beginning I should comment on the quality of Chinese official data on which almost all quantitative studies referred to in this article were based. Chow (2006(a)) has presented the view that by and large the official data are useful and fairly accurate. The main justification is that every time I tested an economic hypothesis or estimated an economic relation using the official data the result confirmed the well-established economic theory. It would be a miracle if I had the power to make the Chinese official statisticians fabricate data to support my hypotheses. Even if I had had the power, most of the data had already been published for years before I conceived the ideas of the studies reported in this article.China, Chinese economy, Taiwan, economic reforms, data
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Evaluation by simulation of interpolation and acceleration algorithms for Stepper Motors
No full textStepper motors are used to control CNC machines for many applications. As well as following the required path precisely, it is also important that the motion be smooth and that the surface speed be controllable. Improved interpolation algorithms for individual straight lines and circular arcs have been developed using distance as a parameter [Chow et al, 2002], [Chow, 2003]. The algorithms control the motor by means of pulses and the generation of the pulse timings is based on the geometry of the shape. For high speeds it is necessary to allow smooth acceleration at the beginning and similar smooth deceleration at the end. Thus, appropriate acceleration and deceleration algorithms have been developed for use with the new interpolation algorithms. This paper describes how simulation has been used to evaluate the new algorithms and compare them with previous algorithms. The algorithms are described for the 2D case but the principle can be extended to 3D
Publication bias (Chow, 2018)
No full textPurpose: The purpose of this research note is to systematically document the extent that researchers who publish in American Speech-Language-Hearing Association (ASHA) journals search for and include unpublished literature in their meta-analyses and test for publication bias.Method: This research note searched all ASHA peer-reviewed journals for published meta-analyses and reviewed all qualifying articles for characteristics related to the acknowledgement and assessment of publication bias.Results: Of meta-analyses published in ASHA journals, 75% discuss publication in some form; however, less than 50% test for publication bias. Further, only 38% (n = 11) interpreted the findings of these tests.Conclusion: Findings reveal that more attention is needed to the presence and impact of publication bias. This research note concludes with 5 recommendations for addressing publication bias.Supplemental Material S1. Summary of common publication bias tests. Chow, J. C. (2018). Prevalence of publication bias tests in speech, language, and hearing research. Journal of Speech, Language, and Hearing Research. Advance online publication. https://doi.org/10.1044/2018_JSLHR-L-18-0098</div
Overexpression of Cyclin D1 and C-Myc Gene Products in Human Primary Epithelial Ovarian Cancer
No full textCyclin D1 and c-Myc are key participants in the cell-cycle pathway, in which aberrancies have been associated with malignant transformation. To date, data on the relationship of expression of these proteins and histologic subtype of epithelial ovarian cancer are still scarce and discordant. Immunohistochemical analysis was performed on 12 normal ovaries and 47 cases of serous, mucinous, endometrioid, and clear cell ovarian carcinomas. No abnormal expression of cyclin D1 or c-Myc was demonstrated in any of the 12 normal ovarian specimens. However, compared to normal ovarian tissues, overexpression of cyclin D1 and c-Myc was observed in 42.6% (20/47) and 65.9% (31/47) of tumors examined, respectively. There was no significant difference of overexpression of cyclin D1 or c-Myc gene products between these four histologic subtypes of ovarian adenocarcinomas. This study shows that cyclin D1 and c-Myc are frequently overexpressed in epithelial ovarian carcinomas, but they are not correlated with a particular histologic subtype. Although our preliminary results need to be validated in a larger number of tumors, the abnormal expression of cyclin D 1 and c-Myc in epithelial ovarian cancer reaffirms the notion that they are crucial components in the pathway of tumorigenesis and deserve further study
Performance and Professional Wrestling
No full textPerformance and Professional Wrestling is the first edited volume to consider professional wrestling explicitly from the vantage point of theatre and performance studies. Moving beyond simply noting its performative qualities or reading it via other performance genres, this collection of essays offers a complete critical reassessment of the popular sport.
Topics such as the suspension of disbelief, simulation, silence and speech, physical culture, and the performance of pain within the squared circle are explored in relation to professional wrestling, with work by both scholars and practitioners grouped into seven short sections:
Audience
Circulation
Lucha
Gender
Queerness
Bodies
Race
A significant re-reading of wrestling as a performing art, Performance and Professional Wrestling makes essential reading for scholars and students intrigued by this uniquely theatrical sport
A Model for National Income Determination in Taiwan
No full textFollowing Chow (1985 and 2010) and using annual data from 1951 to 2010 for Taiwan this paper estimates a consumption function based on the permanent income hypothesis and an investment function based on the accelerations principle. The data support the permanent income hypothesis Friedman (1957) whereas the permanent income hypothesis of Hall (1978) was supported in Chow (1985 and 2010). The accelerations principle is strongly supported, as in the case of China. An explanation why the two economies have different consumption functions is given.consumption, investment, permanent income, Taiwan, macroeconomics
Accounting for Economic Growth in Taiwan and Mainland China: A Comparative Analysis
No full textThis paper provides a statistical summary of aggregate economic growth in Taiwan and mainland China using the standard national income accounting framework by decomposing aggregate growth into components due to growths in capital, labor and total factor productivity. For Taiwan, new series of capital stock and of human capital are constructed. The major findings include (a) the stability of input coefficients (under the assumption of constant returns) and of the rate of increase in TFP for the entire period 1951-1999, (b) a labor exponent of about 0.7 and a rate of annual increase in TFP of about 0.03, and (c) a slower exponential rate of growth of real gdp since 1987 to about 0.065 from the 1951-1999 average of 0.081 mainly as a result of the large reduction in the growth rate of labor input to half. For mainland China, a capital stock series of Chow (1993) was extended to 1998. The major findings include (a) the stability of the relative input coefficients for the entire period 1952-1998 but TFP did not increase until 1979, (b) a labor exponent of about 0.35 and a rate of increase in TFP of about 0.027 after 1979, and (c) the absence of equally large reduction in the rate of increase in labor input as in Taiwan and the smaller exponent of labor leading to a prospect of only a moderate reduction in future growth rate.Growth
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