Search results

Title: Armour Tech News, November 02, 1937
Creator: Armour Institute of Technology
Date: 1937-11-02, 1937-11-02
Collection: Technology News Microfilm collection, 1928-1981

Title: Armour Tech News, November 09, 1937
Creator: Armour Institute of Technology
Date: 1937-11-09, 1937-11-09
Collection: Technology News Microfilm collection, 1928-1981

Title: Armour Tech News, November 16, 1937
Creator: Armour Institute of Technology
Date: 1937-11-16, 1937-11-16
Collection: Technology News Microfilm collection, 1928-1981

Title: Armour Tech News, September 22, 1936
Creator: Armour Institute of Technology
Date: 1936-09-22, 1936-09-22
Collection: Technology News Microfilm collection, 1928-1981

Title: Armour Tech News, November 10, 1936
Creator: Armour Institute of Technology
Date: 1936-11-10, 1936-11-10
Collection: Technology News Microfilm collection, 1928-1981

Title: Armour Tech News, February 16, 1937
Creator: Armour Institute of Technology
Date: 1937-02-16, 1937-02-16
Collection: Technology News Microfilm collection, 1928-1981

Title: Armour Tech News, April 20, 1937
Creator: Armour Institute of Technology
Date: 1937-04-20, 1937-04-20
Collection: Technology News Microfilm collection, 1928-1981

Title: Armour Tech News, October 12, 1937
Creator: Armour Institute of Technology
Date: 1937-10-12, 1937-10-12
Collection: Technology News Microfilm collection, 1928-1981

Title: Armour Tech News, March 01, 1938
Creator: Armour Institute of Technology
Date: 1938-03-01, 1938-03-01
Collection: Technology News Microfilm collection, 1928-1981

Title: Armour Tech News, March 23, 1938
Creator: Armour Institute of Technology
Date: 1938-03-23, 1938-03-23
Collection: Technology News Microfilm collection, 1928-1981

Title: Antarctic Snow Cruiser
Creator: Armour Research Foundation (U.S.)
Date: 1939-08-09
Description: Overhead plan for The Snow Cruiser, designed and checked by Dr. Thomas C. Poulter, drawn by C.E. Hammett, and traced by E.J. Loutzenheiser....
Show moreOverhead plan for The Snow Cruiser, designed and checked by Dr. Thomas C. Poulter, drawn by C.E. Hammett, and traced by E.J. Loutzenheiser. The Snow Cruiser was designed by Armour Research Foundation Scientific Director Thomas C. Poulter, constructed by ARF, and taken on Richard Byrd's third Antarctic expedition.
Show less
Collection: Henry T. Heald, University President's papers, 1920-1953

Title: Antarctic Snow Cruiser
Creator: Armour Research Foundation (U.S.)
Date: 1939-08-09
Description: Plan for The Snow Cruiser, designed and checked by Dr. Thomas C. Poulter, drawn by C.E. Hammett, and traced by E.J. Loutzenheiser. The Snow...
Show morePlan for The Snow Cruiser, designed and checked by Dr. Thomas C. Poulter, drawn by C.E. Hammett, and traced by E.J. Loutzenheiser. The Snow Cruiser was designed by Armour Research Foundation Scientific Director Thomas C. Poulter, constructed by ARF, and taken on Richard Byrd's third Antarctic expedition.
Show less
Collection: Henry T. Heald, University President's papers, 1920-1953

Title: Binary hidden Markov models and varieties, AS2012 Special Volume, part 2: This issue includes a second series of papers from talks, posters and collaborations resulting from and inspired by the Algebraic Statistics in the Alleghenies Conference at Penn State, which took place in July 2012.
Creator: Critch, Andrew
Date: 2013, 2013
Description: This paper closely examines HMMs in which all the hidden random variables are...
Show moreThis paper closely examines HMMs in which all the hidden random variables are binary. Its main contributions are (1) a birational parametrization for every such HMM, with an explicit inverse for recovering the hidden parameters in terms of observables, (2) a semialgebraic model membership test for every such HMM, and (3) minimal dening equations for the 4-node fully binary model, comprising 21 quadrics and 29 cubics, which were computed using Grobner bases in the cumulant coordinates of Sturmfels and Zwiernik. The new model parameters in (1) are rationally identiable in the sense of Sullivant, Garcia-Puente, and Spielvogel, and each model's Zariski closure is therefore a rational projective variety of dimension 5. Grobner basis computations for the model and its graph are found to be considerably faster using these parameters. In the case of two hidden states, item (2) supersedes a previous algorithm of Schonhuth which is only generically dened, and the dening equations (3) yield new invariants for HMMs of all lengths 4. Such invariants have been used successfully in model selection problems in phylogenetics, and one can hope for similar applications in the case of HMMs.
Show less
Collection: Journal of Algebraic Statistics

Title: On Polyhedral Approximations of Polytopes for Learning Bayesian Networks, AS2012 Special Volume, part 2: This issue includes a second series of papers from talks, posters and collaborations resulting from and inspired by the Algebraic Statistics in the Alleghenies Conference at Penn State, which took place in July 2012.
Creator: Studeny, Milan, Haws, David C.
Date: 2013, 2013
Description: The motivation for this paper is the geometric approach to statistical learning Bayesiannetwork (BN) structures. We review three vector...
Show moreThe motivation for this paper is the geometric approach to statistical learning Bayesiannetwork (BN) structures. We review three vector encodings of BN structures. The first one has been used by Jaakkola et al. [9] and also by Cussens [4], the other two use special integral vectors formerly introduced, called imsets [18, 20]. The topic is the comparison of outer polyhedral approximations of the corresponding polytopes. We show how to transform the inequalities suggested by Jaakkola et al. [9] into the framework of imsets. The result of our comparison is the observation that the implicit polyhedral approximation of the standard imset polytope suggested in [21] gives a tighter approximation than the (transformed) explicit polyhedral approximation from [9]. As a consequence, we confirm a conjecture from [21] that the above-mentioned implicit polyhedral approximation of the standard imset polytope is an LP relaxation of that polytope. In the end, we review recent attempts to apply the methods of integer programming to learning BN structures and discuss the task of finding suitable explicit LP relaxation in the imset-based approach.
Show less
Collection: Journal of Algebraic Statistics

Title: Learning Coefficient in Bayesian Estimation of Restricted Boltzmann Machine, AS2012 Special Volume, part 2: This issue includes a second series of papers from talks, posters and collaborations resulting from and inspired by the Algebraic Statistics in the Alleghenies Conference at Penn State, which took place in July 2012.
Creator: Aoyagi, Miki
Date: 2013, 2013
Description: We consider the real log canonical threshold for the learning model in Bayesian estimation. This threshold corresponds to a learning...
Show moreWe consider the real log canonical threshold for the learning model in Bayesian estimation. This threshold corresponds to a learning coefficient of generalization error in Bayesian estimation, which serves to measure learning efficiency in hierarchical learning models [30, 31, 33]. In this paper, we clarify the ideal which gives the log canonical threshold of the restricted Boltzmann machine and consider the learning coefficients of this model.
Show less
Collection: Journal of Algebraic Statistics

Title: Phylogenetic invariants for group-based models, AS2012 Special Volume, part 1: This issue includes a second series of papers from talks, posters and collaborations resulting from and inspired by the Algebraic Statistics in the Alleghenies Conference at Penn State, which took place in July 2012.
Creator: Donten-Bury, Maria, Michalek, Mateusz
Date: 2012, 2012
Description: In this paper we investigate properties of algebraic varieties representing group-based phylogenetic models. We propose a method of generating...
Show moreIn this paper we investigate properties of algebraic varieties representing group-based phylogenetic models. We propose a method of generating many phylogenetic invariants. We prove that we obtain all invariants for any tree for the two-state Jukes-Cantor model. We conjecture that for a large class of models our method can give all phylogenetic invariants for any tree. We show that for 3-Kimura our conjecture is equivalent to the conjecture of Sturmfels and Sullivant [22, Conjecture 2]. This, combined with the results in [22], would make it possible to determine all phylogenetic invariants for any tree for 3-Kimura model, and also other phylogenetic models. Next we give the (first) examples of non-normal varieties associated to general group-based model for an abelian group. Following Kubjas [17] we prove that for many group-based models varieties associated to trees with the same number of leaves do not have to be deformation equivalent.
Show less
Collection: Journal of Algebraic Statistics

Title: Properties of semi-elementary imsets as sums of elementary imsets
Creator: Kashimura, Takuya, Sei, Tomonari, Takemura, Akimichi, Tanaka, Kentaro
Date: 2011, 2011
Description: We study properties of semi-elementary imsets and elementary imsets introduced by Studeny [10]. The rules of the semi-graphoid axiom ...
Show moreWe study properties of semi-elementary imsets and elementary imsets introduced by Studeny [10]. The rules of the semi-graphoid axiom (decomposition, weak union and contraction) for conditional independence statements can be translated into a simple identity among three semi-elementary imsets. By recursively applying the identity, any semi-elementary imset can be written as a sum of elementary imsets, which we call a representation of the semi-elementary imset. A semi-elementary imset has many representations. We study properties of the set of possible representations of a semi-elementary imset and prove that all representations are connected by relations among four elementary imsets.
Show less
Collection: Journal of Algebraic Statistics

Title: Higher Connectivity of Fiber Graphs of Gröbner Bases, AS2012 Special Volume, part 2: This issue includes a second series of papers from talks, posters and collaborations resulting from and inspired by the Algebraic Statistics in the Alleghenies Conference at Penn State, which took place in July 2012.
Creator: Potka, Samu
Date: 2013, 2013
Description: Fiber graphs of Gröbner bases from contingency tables are important in statistical hypothesis testing, where one studies random walks on these...
Show moreFiber graphs of Gröbner bases from contingency tables are important in statistical hypothesis testing, where one studies random walks on these graphs using the Metropolis-Hastings algorithm. The connectivity of the graphs has implications on how fast the algorithm converges. In this paper, we study a class of ber graphs with elementary combinatorial techniques and provide results that support a recent conjecture of Engström: the connectivity is given by the minimum vertex degree.
Show less
Collection: Journal of Algebraic Statistics

Title: An Iterative Method Converging to a Positive Solution of Certain Systems of Polynomial Equations
Creator: Cartwright, Dustin
Date: 2011, 2011
Description: We present a numerical algorithm for finding real non-negative solutions to a certain class of polynomial equations. Our methods are based on...
Show moreWe present a numerical algorithm for finding real non-negative solutions to a certain class of polynomial equations. Our methods are based on the expectation maximization and iterative proportional fitting algorithms, which are used in statistics to find maximum likelihood parameters for certain classes of statistical models. Since our algorithm works by iteratively improving an approximate solution, we find approximate solutions in the cases when there are no exact solutions, such as overconstrained systems.
Show less
Collection: Journal of Algebraic Statistics

Title: Geometry of Higher-Order Markov Chains, AS2012 Special Volume, part 1: This issue includes a second series of papers from talks, posters and collaborations resulting from and inspired by the Algebraic Statistics in the Alleghenies Conference at Penn State, which took place in July 2012.
Creator: Sturmfels, Bernd
Date: 2012, 2012
Description: We determine an explicit Gr ?obner basis, consisting of linear forms and determinantal quadrics, for the prime ideal of Raftery’s mixture...
Show moreWe determine an explicit Gr ?obner basis, consisting of linear forms and determinantal quadrics, for the prime ideal of Raftery’s mixture transition distribution model for Markov chains. When the states are binary, the corresponding projective variety is a linear space, the model itself consists of two simplices in a cross-polytope, and the likelihood function typically has two local maxima. In the general non-binary case, the model corresponds to a cone over a Segre variety.
Show less
Collection: Journal of Algebraic Statistics

repository.iit

Search the repository

Pages

Pages

Enabled Filters

Refine Results

Type

Date

Academic status of creator

Department

Subject

Creator

Part of

Rights