Limit Theorems for Estimating the Parameters of Differentiated Product Demand Systems

We provide an asymptotic distribution theory for a class of Generalized Method of Moments estimators that arise in the study of differentiated product markets when the number of observations is associated with the number of products within a given market. We allow for three sources of error: the sampling error in estimating market shares, the simulation error in approximating the shares predicted by the model, and the underlying model error. The limiting distribution of the parameter estgimator is normal provided the size of the consumer sample and the number of simulation draws grow at a large enough rate relative to the number of products. The required rates differ for two frequently used demand models, and a small Monte Carlo study shows that the difference in asymptotic properties of the two models are reflected in the models' small sample properties. The differences impact directly on the computational burden of the two models.Choice models, Method of Moments, Multinominal, Random Coefficients, Vertical Model

Identifying long cycles in finite alternating and symmetric groups acting on subsets

Let $H$ be a permutation group on a set $\Lambda$, which is permutationally isomorphic to a finite alternating or symmetric group $A_n$ or $S_n$ acting on the $k$-element subsets of points from $\{1,\ldots,n\}$, for some arbitrary but fixed $k$. Suppose moreover that no isomorphism with this action is known. We show that key elements of $H$ needed to construct such an isomorphism $\varphi$, such as those whose image under $\varphi$ is an $n$-cycle or $(n-1)$-cycle, can be recognised with high probability by the lengths of just four of their cycles in $\Lambda$.Comment: 45 page

Soil experiment

An experimental procedure was devised to investigate the effects of the lunar environment on the physical properties of simulated lunar soil. The test equipment and materials used consisted of a vacuum chamber, direct shear tester, static penetrometer, and fine grained basalt as the simulant. The vacuum chamber provides a medium for applying the environmental conditions to the soil experiment with the exception of gravity. The shear strength parameters are determined by the direct shear test. Strength parameters and the resistance of soil penetration by static loading will be investigated by the use of a static cone penetrometer. In order to conduct a soil experiment without going to the moon, a suitable lunar simulant must be selected. This simulant must resemble lunar soil in both composition and particle size. The soil that most resembles actual lunar soil is basalt. The soil parameters, as determined by the testing apparatus, will be used as design criteria for lunar soil engagement equipment

Hopf monads on monoidal categories

We define Hopf monads on an arbitrary monoidal category, extending the definition given previously for monoidal categories with duals. A Hopf monad is a bimonad (or opmonoidal monad) whose fusion operators are invertible. This definition can be formulated in terms of Hopf adjunctions, which are comonoidal adjunctions with an invertibility condition. On a monoidal category with internal Homs, a Hopf monad is a bimonad admitting a left and a right antipode. Hopf monads generalize Hopf algebras to the non-braided setting. They also generalize Hopf algebroids (which are linear Hopf monads on a category of bimodules admitting a right adjoint). We show that any finite tensor category is the category of finite-dimensional modules over a Hopf algebroid. Any Hopf algebra in the center of a monoidal category C gives rise to a Hopf monad on C. The Hopf monads so obtained are exactly the augmented Hopf monads. More generally if a Hopf monad T is a retract of a Hopf monad P, then P is a cross product of T by a Hopf algebra of the center of the category of T-modules (generalizing the Radford-Majid bosonization of Hopf algebras). We show that the comonoidal comonad of a Hopf adjunction is canonically represented by a cocommutative central coalgebra. As a corollary, we obtain an extension of Sweedler's Hopf module decomposition theorem to Hopf monads (in fact to the weaker notion of pre-Hopf monad).Comment: 45 page

HPC-GAP: engineering a 21st-century high-performance computer algebra system

Symbolic computation has underpinned a number of key advances in Mathematics and Computer Science. Applications are typically large and potentially highly parallel, making them good candidates for parallel execution at a variety of scales from multi-core to high-performance computing systems. However, much existing work on parallel computing is based around numeric rather than symbolic computations. In particular, symbolic computing presents particular problems in terms of varying granularity and irregular task sizes thatdo not match conventional approaches to parallelisation. It also presents problems in terms of the structure of the algorithms and data. This paper describes a new implementation of the free open-source GAP computational algebra system that places parallelism at the heart of the design, dealing with the key scalability and cross-platform portability problems. We provide three system layers that deal with the three most important classes of hardware: individual shared memory multi-core nodes, mid-scale distributed clusters of (multi-core) nodes, and full-blown HPC systems, comprising large-scale tightly-connected networks of multi-core nodes. This requires us to develop new cross-layer programming abstractions in the form of new domain-specific skeletons that allow us to seamlessly target different hardware levels. Our results show that, using our approach, we can achieve good scalability and speedups for two realistic exemplars, on high-performance systems comprising up to 32,000 cores, as well as on ubiquitous multi-core systems and distributed clusters. The work reported here paves the way towards full scale exploitation of symbolic computation by high-performance computing systems, and we demonstrate the potential with two major case studies

Easy on that trigger dad: a study of long term family photo retrieval

We examine the effects of new technologies for digital photography on people's longer term storage and access to collections of personal photos. We report an empirical study of parents' ability to retrieve photos related to salient family events from more than a year ago. Performance was relatively poor with people failing to find almost 40% of pictures. We analyze participants' organizational and access strategies to identify reasons for this poor performance. Possible reasons for retrieval failure include: storing too many pictures, rudimentary organization, use of multiple storage systems, failure to maintain collections and participants' false beliefs about their ability to access photos. We conclude by exploring the technical and theoretical implications of these findings

Влияние супероксидного анион-радикала и глутатиона на липолиз в адипоцитах крыс при окислительном стрессе, индуцированном аллоксаном

Установлено, что в адипоцитах крыс при действии аллоксана развивается окислительный стресс, сопровождающийся увеличением спонтанного липолиза и ингибированием стимулированного агонистом beta2-адренорецепторов изопротеренолом липолиза. На основании полученных данных сделан вывод о влиянии активных форм кислорода, в частности супероксидного анион-радикала, и системы глутатиона на молекулярные механизмы изменения интенсивности липолиза в адипоцитах крыс в условиях окислительного стресса, индуцированного аллоксаном

Damage Arresting Composites for Shaped Vehicles - Phase II Final Report

This report describes the development of a novel structural concept, Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), that addresses the demanding fuselage loading requirements for the Hybrid Wing or Blended Wing Body (BWB) airplane configuration. In addition to the analytical studies, a three specimen test program was also completed to assess the concept under axial tension loading, axial compression loading, and internal pressure loading

Prospectus, February 22, 1978

IS ANNEXATION TO CHAMPAIGN INEVITABLE?; A real stew in Stu-Go; Letters to the editor: Laudations for lifespan workshop, More on saving PLATO; Parkland College News in Brief: Keep out of handicapped parking….Or else!; Black Woman\u27s workshop, Parkland serves unusual course; SSU rep. here Tues., Next CHI program: SIDS, Writers needed to publish, Long lifers 4th annual arts and crafts show; Speech team keeps on talking; Table tennis, anyone?: Parkland\u27s Phan takes second at U of I; Happy Birthington\u27s Washday, everyone!; MTD bus schedule changes affect Parkland commuters; Star-gazers glance back and foretell an icy future; Classifieds; Humane Society has no choice...: Unwanted, unloved...animals die by the thousands; March Madness just around the corner: Area roundballers down to the wire; Men\u27s team tops CIAC: Regular season over: 22-4!; IM basketball titles still up for grabs; Arkansas-Houston game is fooler; Women finish season with loss to Olney at sectional; Bouncing Bob Basketball Bonanzahttps://spark.parkland.edu/prospectus_1978/1024/thumbnail.jp

Prospectus, May 19, 1975

MCMULLEN WINS PRESIDENCY; PC News….In Brief: Library Extends Hours, Registration By Mail Deadline May 27, New Officers For Chi Gamma; StuGo Budget Vetoed; VP Race Squeaker; Betty Furness To Address Grads; Dental Students Capped; Statutory Rape: Crime Without A Victim; StuGo Minutes; More StuGo Minutes; Fine Arts Week At Parkland; $9000...Where Does The Priority Lie?; The Kaleidoscope; The Short Circuit; letters; L.T.D.s Corner: OFF Without A Hitch...Almost; To The 1975 College Grads; Parkland: The Year In Review; Le Finis; Skylines; Chess Talk: Chess Notation; Congratulations to Mrs. Teresa Wells...; It\u27s Not Too Late For A Summer Job In Europe; Cimmeron Brings Insane Happiness; Suggestion Box; Wiechman Recieves ROTC Scholarship; What If...; Movie Revue: \u27Shampoo\u27; May 22nd: \u27Slink Rand\u27; Zappa Captivates Chicago; My Friendly Tree; Wanted: Reporters; Student Elections: Opinion Poll; S.I.U. Has New LibTech Program; Fine Arts Week; Classified Ads; Outside Life At PC; NROTC Scholarship Pgrogram; New Record For Bike Race; Sports Views; Trackmen Third In State; Cobras\u27 Win Streak Broken; Final Examination Schedule; Problems? Learning Lab Can Help; New Pharmacology Class; Awards Given At IOC Banquethttps://spark.parkland.edu/prospectus_1975/1009/thumbnail.jp