A probabilistic multi-touch attribution model for online advertising

It is an important problem in computational advertising to study the effects of different advertising channels upon user conversions, as advertisers can use the discoveries to plan or optimize advertising campaigns. In this paper, we propose a novel Probabilistic Multi-Touch Attribution (PMTA) model which takes into account not only which ads have been viewed or clicked by the user but also when each such interaction occurred. Borrowing the techniques from survival analysis, we use the Weibull distribution to describe the observed conversion delay and use the hazard rate of conversion to measure the influence of an ad exposure. It has been shown by extensive experiments on a large real-world dataset that our proposed model is superior to state-of-the-art methods in both conversion prediction and attribution analysis. Furthermore, a surprising research finding obtained from this dataset is that search ads are often not the root cause of final conversions but just the consequence of previously viewed ads

Noncommutative Computer Algebra in the Control of Singularly Perturbed Dynamical Systems

Most algebraic calculations which one sees in linear systems theory, for example in IEEE TAC, involve block matrices and so are highly noncommutative. Thus conventional commutative computer algebra packages, as in Mathematica and Maple, do not address them. Here we investigate the usefulness of noncommutative computer algebra in a particular area of control theory-singularly perturbed dynamic systems-where working with the noncommutative polynomials involved is especially tedious. Our conclusion is that they have considerable potential for helping practitioners with such computations. For example, the methods introduced here take the most standard textbook singular perturbation calculation, [KK086], one step further than had been done previously. Commutative Groebner basis algorithms are powerful and make up the engines in symbolic algebra packages’ Solve commands. Noncommutative Groebner basis algorithms are more recent, but we shall see that they are useful in manipulating the messy sets of noncommutative polynomial equations which arise in singular perturbation calculations. We use the noncommutative algebra package NCAlgebra and the noncommutative Groebner basis package NCGB which runs under it

From social contract to 'social contrick' : the depoliticisation of economic policy-making under Harold Wilson, 1974–75

The 1974-79 Labour Governments were elected on the basis of an agreement with the TUC promising a redistribution of income and wealth known as the Social Contract. However, the Government immediately began to marginalise these commitments in favour of preferences for incomes policy and public expenditure cuts, which has led the Social Contract to be described as the 'Social Contrick'. These changes were legitimised through a process of depoliticisation, and using an Open Marxist framework and evidence from the National Archives, the paper will show that the Treasury's exchange rate strategy and the need to secure external finance placed issues of confidence at the centre of political debate, allowing the Government to argue there was no alternative to the introduction of incomes policy and the reduction of public expenditure

Recent Decisions

Comments on recent decisions by Robert E. Veverka, John W. Dell, James A. Wysocki, Theodore A. Fitzgerald, Robert W. Cox, Philip B. Byrne, Thomas R. Joyce, and Cornelius Collins

A Hierarchical Bayesian Modeling Approach for the Habitat Distribution of Smooth Dogfish by Sex and Season in Inshore Coastal Waters of the US Northwest Atlantic

The Smooth Dogfish Mustelus canis is an abundant, small coastal shark occurring along the U.S. Atlantic coast. Despite being targeted by a directed fishery and having recently undergone a stock assessment that found the population neither overfished nor experiencing overfishing, little is known about the spatial and temporal distribution of this species. Here, we used catch data from the spring and fall Northeast Area Monitoring and Assessment Program\u27s fishery-independent trawl surveys conducted between 2007 and 2016 and various environmental factors to perform hierarchical Bayesian modeling as a first attempt to spatially predict adult Smooth Dogfish CPUE in U.S. northwest Atlantic Ocean waters by sex and season. Relevant environmental variables differed between both sexes and seasons. Male and female CPUEs were similarly associated with lower salinity and shallower depth in the spring. During fall, male CPUE was associated with sea surface temperature and bottom rugosity, and female CPUE was associated with chlorophyll-a concentration, bottom rugosity, and year. Habitat modeling results predicted that areas of high male and female CPUEs would overlap during spring but strongly diverge during fall, when greater predicted CPUEs for males were distributed considerably farther north. These results suggest sexual segregation among Smooth Dogfish during fall, with the springtime overlap in distribution coinciding with the pupping and mating season in this population. This difference in distribution during fall may allow for a male-only directed fishery for Smooth Dogfish in the northern extent of the species\u27 range in waters near southern New England and Georges Bank

An assessment of John Deere dealership service personnel needs and service managers' perceptions of the John Deere Ag Tech program

Doctor of PhilosophyDepartment of Secondary EducationSteven R. HarbstreitJohn Deere Corporation sponsors 16 schools within the United States that are designed to educate students to become future agricultural equipment technicians. At the time of this study, the schools’ enrollments were at a less-than desirable level, 80% capacity. However, the company was receiving feedback that dealerships needed technicians. The need to determine the disparity between the need for technicians and the level of enrollment led to the pursuit of this study. The researcher sampled 306 John Deere agricultural service managers across the continental United States to determine: (a) if the dealerships truly needed technicians, (b) the methods dealerships were using for locating technicians, and (c) the service managers’ perceptions of the John Deere (JD) Ag Tech program. The study also analyzed the relationships between the service managers’ perceptions of the JD Ag Tech program and five independent variables: (a) number of technicians employed at John Deere dealerships, (b) number of stores dealer-organizations own, (c) distance between John Deere dealerships and the closest JD Ag Tech school, (d) number of JD Ag Tech students John Deere dealerships have sponsored, and (e) service managers’ age. The results of the study indicated that John Deere service managers did plan to hire technicians over the next 12 months as well as over the next three years. However, it was also determined that 60% of the service managers were only somewhat knowledgeable or unfamiliar with the JD Ag Tech Program. For the service managers that had experienced sponsoring JD Ag Tech students, those service managers were satisfied with the JD Ag Tech graduates. The researcher’s recommendations focused upon two areas. The first was to improve the marketing of the JD Ag Tech program to insure that all John Deere service managers become familiar with the program. The second recommendation was to focus on improving the “student” component of the partnership, by recruiting the students earlier in their high school careers, and having the partners work together to target high caliber students

Late Miocene to early Pliocene biofacies of Wanganui and Taranaki Basins, New Zealand: Applications to paleoenvironmental and sequence stratigraphic analysis

The Matemateaonga Formation is late Miocene to early Pliocene (upper Tongaporutuan to lower Opoitian New Zealand Stages) in age. The formation comprises chiefly shellbeds, siliciclastic sandstone, and siltstone units and to a lesser extent non-marine and shallow marine conglomerate and rare paralic facies. The Matemateaonga Formation accumulated chiefly in shelf paleoenvironments during basement onlap and progradation of a late Miocene to early Pliocene continental margin wedge in the Wanganui and Taranaki Basins. The formation is strongly cyclothemic, being characterised by recurrent vertically stacked facies successions, bounded by sequence boundaries. These facies accumulated in a range of shoreface to mid-outer shelf paleoenvironments during conditions of successively oscillating sea level. This sequential repetition of facies and the biofacies they enclose are the result of sixth-order glacio-eustatic cyclicity. Macrofaunal associations have been identified from statistical analysis of macrofossil occurrences collected from multiple sequences. Each association is restricted to particular lithofacies and stratal positions and shows a consistent order and/or position within the sequences. This pattern of temporal paleoecologic change appears to be the result of lateral, facies-related shifting of broad biofacies belts, or habitat-tracking, in response to fluctuations of relative sea level, sediment flux, and other associated paleoenvironmental variables. The associations also show strong similarity in terms of their generic composition to biofacies identified in younger sedimentary strata and the modern marine benthic environment in New Zealand

Experiences in Interagency and International Interfaces for Mission Support

The Flight Dynamics Division (FDD) of the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GFSC) provides extensive support and products for Space Shuttle missions, expendable launch vehicle launches, and routine on-orbit operations for a variety of spacecraft. A major challenge in providing support for these missions is defining and generating the products required for mission support and developing the method by which these products are exchanged between supporting agencies. As interagency and international cooperation has increased in the space community, the FDD customer base has grown and with it the number and variety of external interfaces and product definitions. Currently, the FDD has working interfaces with the NASA Space and Ground Networks, the Johnson Space Center, the White Sands Complex, the Jet propulsion Laboratory (including the Deep Space Network), the United States Air Force, the Centre National d'Etudes Spatiales, the German Spaceflight Operations Center, the European Space Agency, and the National Space Development Agency of Japan. With the increasing spectrum of possible data product definitions and delivery methods, the FDD is using its extensive interagency experience to improve its support of established customers and to provide leadership in adapting/developing new interfaces. This paper describes the evolution of the interfaces between the FDD and its customers, discusses many of the joint activities ith these customers, and summarizes key lessons learned that can be applied to current and future support