EMPIRICISM AND THE ART OF TEACHING

Teaching/Communication/Extension/Profession,

THE SOUTHERN AGRICULTURAL ECONOMICS ASSOCIATION AND RESIDENT INSTRUCTION

Teaching/Communication/Extension/Profession,

Approximately Minwise Independence with Twisted Tabulation

A random hash function $h$ is $\varepsilon$-minwise if for any set $S$, $|S|=n$, and element $x\in S$, $\Pr[h(x)=\min h(S)]=(1\pm\varepsilon)/n$. Minwise hash functions with low bias $\varepsilon$ have widespread applications within similarity estimation. Hashing from a universe $[u]$, the twisted tabulation hashing of P\v{a}tra\c{s}cu and Thorup [SODA'13] makes $c=O(1)$ lookups in tables of size $u^{1/c}$. Twisted tabulation was invented to get good concentration for hashing based sampling. Here we show that twisted tabulation yields $\tilde O(1/u^{1/c})$-minwise hashing. In the classic independence paradigm of Wegman and Carter [FOCS'79] $\tilde O(1/u^{1/c})$-minwise hashing requires $\Omega(\log u)$-independence [Indyk SODA'99]. P\v{a}tra\c{s}cu and Thorup [STOC'11] had shown that simple tabulation, using same space and lookups yields $\tilde O(1/n^{1/c})$-minwise independence, which is good for large sets, but useless for small sets. Our analysis uses some of the same methods, but is much cleaner bypassing a complicated induction argument.Comment: To appear in Proceedings of SWAT 201

CHARACTERISTICS OF AGRICULTURAL ECONOMICS UNDERGRADUATE ADVISING IN THE WESTERN REGION

The quality of faculty advising has been a source of concern among students and faculty. As an initial attempt at addressing these concerns this paper summarizes the results of a faculty advising study in undergraduate agricultural economics programs. Various advising program characteristics among western schools are discussed and contrasted to schools in other regions. Interregional and interdepartmental variation was found in advisor resource allocation, advising program implementation, rewards and priorities, and evaluations of advising quality. Despite larger enrollments, smaller advising budgets, less support and lower rewards for advising, schools in the West reported advising quality comparable if not superior to that in other regions.Teaching/Communication/Extension/Profession,

ENERGY EFFICIENCY IN FOOD PROCESSING IN THE SOUTHERN REGION

Agribusiness,

TEACHING CONSUMER ECONOMICS USING TASTE PANELS

Consumer/Household Economics,

RESEARCH PRODUCTIVITY AND SELECTED CHARACTERISTICS OF AGRICULTURAL ECONOMICS RESEARCH AND TEACHING FACULTY IN THE SOUTHERN REGION

Teaching/Communication/Extension/Profession,

ASSESSMENT OF JOURNALS USED BY AGRICULTURAL ECONOMISTS AT LAND-GRANT UNIVERSITIES

Agricultural economists at land-grant universities were surveyed to evaluate the use and assessment of professional journals. Faculty rankings of journals are reported along with faculty perceptions of changes in the quality of selected journals. Of 25 journals used by agricultural economics faculties, the Southern Journal of Agricultural Economics ranked first among regional agricultural economics journals in personal usefulness, subscriptions held, papers submitted, papers published, and participation in the editorial and review processes. The SJAE was also ranked as the second most improved journal among all journals evaluated.Teaching/Communication/Extension/Profession,

Accelerated growth in outgoing links in evolving networks: deterministic vs. stochastic picture

In several real-world networks like the Internet, WWW etc., the number of links grow in time in a non-linear fashion. We consider growing networks in which the number of outgoing links is a non-linear function of time but new links between older nodes are forbidden. The attachments are made using a preferential attachment scheme. In the deterministic picture, the number of outgoing links $m(t)$ at any time $t$ is taken as $N(t)^\theta$ where $N(t)$ is the number of nodes present at that time. The continuum theory predicts a power law decay of the degree distribution: $P(k) \propto k^{-1-\frac{2} {1-\theta}}$, while the degree of the node introduced at time $t_i$ is given by $k(t_i,t) = t_i^{\theta}[ \frac {t}{t_i}]^{\frac {1+\theta}{2}}$ when the network is evolved till time $t$. Numerical results show a growth in the degree distribution for small $k$ values at any non-zero $\theta$. In the stochastic picture, $m(t)$ is a random variable. As long as $$is independent of time, the network shows a behaviour similar to the Barab\'asi-Albert (BA) model. Different results are obtained when$$ is time-dependent, e.g., when $m(t)$ follows a distribution $P(m) \propto m^{-\lambda}$. The behaviour of $P(k)$ changes significantly as $\lambda$ is varied: for $\lambda > 3$, the network has a scale-free distribution belonging to the BA class as predicted by the mean field theory, for smaller values of $\lambda$ it shows different behaviour. Characteristic features of the clustering coefficients in both models have also been discussed.Comment: Revised text, references added, to be published in PR

QUASI-EXPERIMENTAL DESIGNS FOR MEASURING IMPACTS OF DEVELOPMENTAL HIGHWAYS IN RURAL AREAS

Quasi-experimental techniques were developed to provide decision-making tools for documenting the impacts of developmental highways in rural areas. Regression discontinuity analysis (RDA) with limited observations was used to compare economic changes in highway counties to those in adjacent and non-adjacent control counties. The RDA models found statistically significant changes in population, per capita income, and taxable sales related to highway development. The study found that some counties benefited from developmental highways, some were unchanged, while some experienced economic decline. RDA models with adjacent controls had better explanatory powers while those with non-adjacent controls were more sensitive to highway-related changes in economic activity. When significant non-highway activities were present, adjacent control models may have understated highway-related impacts, while non-adjacent control models may have overstated these impacts. Arguments for using adjacent and non-adjacent experimental designs are discussed.Community/Rural/Urban Development,