Showing posts with label towards. Show all posts
Showing posts with label towards. Show all posts

Advances in Variational Inference Working Towards Large scale Probabilistic Machine Learning at NIPS 2014



At Google, we continually explore and develop large-scale machine learning systems to improve our user’s experience, such as providing better video recommendations, deciding on the best language translation in a given context, or improving the accuracy of image search results. The data used to train these systems often contains many inconsistencies and missing elements, making progress towards large-scale probabilistic models designed to address these problems an important and ongoing part of our research. One principled and efficient approach for developing such models relies on an approach known as Variational Inference.

A renewed interest and several recent advances in variational inference1,2,3,4,5,6 has motivated us to support and co-organise this year’s workshop on Advances in Variational Inference as part of the Neural Information Processing Systems (NIPS) conference in Montreal. These advances include new methods for scalability using stochastic gradient methods, the ability to handle data that arrives continuously as a stream, inference in non-linear time-series models, principled regularisation in deep neural networks, and inference-based decision making in reinforcement learning, amongst others.

Whilst variational methods have clearly emerged as a leading approach for tractable, large-scale probabilistic inference, there remain important trade-offs in speed, accuracy, simplicity and applicability between variational and other approximative schemes. The goal of the workshop will be to contextualise these developments and address some of the many unanswered questions through:

  • Contributed talks from 6 speakers who are leading the resurgence of variational inference, and shaping the debate on topics of stochastic optimisation, deep learning, Bayesian non-parametrics, and theory.
  • 34 contributed papers covering significant advances in methodology, theory and applications including efficient optimisation, streaming data analysis, submodularity, non-parametric modelling and message passing.
  • A panel discussion with leading researchers in the field that will further interrogate these ideas. Our panelists are David Blei, Neil Lawrence, Shinichi Nakajima and Matthias Seeger.

The workshop presents a fantastic opportunity to discuss the opportunities and obstacles facing the wider adoption of variational methods. The workshop will be held on the 13th December 2014 at the Montreal Convention and Exhibition Centre. For more details see: www.variationalinference.org.

References:

1. Rezende, Danilo J., Shakir Mohamed, and Daan Wierstra, Stochastic Backpropagation and Approximate Inference in Deep Generative Models, Proceedings of the 31st International Conference on Machine Learning (ICML-14), 2014.

2. Gregor, Karol, Ivo Danihelka, Andriy Mnih, Charles Blundell and Daan Wierstra, Deep AutoRegressive Networks, Proceedings of the 31st International Conference on Machine Learning (ICML-14), 2014.

3. Mnih, Andriy, and Karol Gregor, Neural Variational Inference and Learning in Belief Networks, Proceedings of the 31st International Conference on Machine Learning (ICML-14), 2014.

4. Kingma, D. P. and Welling, M., Auto-Encoding Variational Bayes, Proceedings of the International Conference on Learning Representations (ICLR), 2014.

5. Broderick, T., Boyd, N., Wibisono, A., Wilson, A. C., & Jordan, M., Streaming Variational Bayes, Advances in Neural Information Processing Systems (pp. 1727-1735), 2013.

6. Hoffman, M., Blei, D. M., Wang, C., and Paisley, J., Stochastic Variational Inference, Journal of Machine Learning Research, 14:1303–1347, 2013.
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    The Computer Science Pipeline and Diversity Part 2 Some positive signs and looking towards the future



    (Cross-posted on the Google for Education Blog)

    The disparity between the growing demand for computing professionals and the number of graduates in Computer Science (CS) and Information Technology (IT) has been highlighted in many recent publications. The tiny pipeline of diverse students (women and underrepresented minorities (URMs)) is even more troubling. Some of the factors causing these issues are:
    • The historical lack of STEM (Science, Technology, Engineering and Mathematics) capabilities in our younger students; lack of proficiency has had a substantial impact on the overall number of students pursuing technical careers. (PCAST Stem Ed report, 2010)
    • On the lack of girls in computing, boys often come into computing knowing more than girls because they have been doing it longer. This can cause girls to lose confidence with the perception that computing is a man’s world. Lack of role models, encouragement and relevant curriculum are additional factors that discourage girls’ participation. (Margolis 2003)
    • On the lack of URMs in computing, the best and most enthusiastic minority students are effectively discouraged from pursuing technical careers because of systemic and structural issues in our high schools and communities, and because of unconscious bias of teachers and administrators. (Margolis, 2010)
    Over the last 3-4 years, however, we have seen some significant positive signals in STEM education in general, and in CS/IT in particular.
    • Math1 and Science2 results as measured by the National Assessment of Educational Progress (NAEP) have improved slightly since 2009, both in general and for female and minority students.
    • Over the last 10 years, there has been an increase in the number of students earning STEM degrees, but the news on women graduates is not as positive.
    “Overall, 40 percent of bachelors degrees earned by men and 29 percent earned by women are now in STEM fields. At the doctoral level, more than half of the degrees earned by men (58 percent) and one-third earned by women (33 percent) are in STEM fields. At the bachelors degree level, though, women are losing ground. Between 2004 and 2014, the share of STEM-related bachelors degrees earned by women decreased in all seven discipline areas: engineering; computer science; earth, atmospheric and ocean sciences; physical sciences; mathematics; biological and agricultural sciences; and social sciences and psychology. The biggest decrease was in computer science, where women now earn 18 percent of bachelors degrees (18 percent). In 2004, women earned nearly a quarter of computer science bachelors degrees, at 23 percent.” - (U.S. News, 2015)
    • There has been a steady growth in investment in education companies, particularly those focused on innovative uses of technology.
    • The number of publications in Google Scholar on STEM education that focus on gender issues or minority students has steadily increased over the last several years.
    Results from Google Scholar, using “STEM education minority” and “STEM education gender” as search terms
    • Successful marketing campaigns such as Hour of Code and Made with Code have helped raise awareness on the accessibility and importance of coding, and the diverse career opportunities in CS.
    • There has been growth in developer bootcamps over the last few years, as well as online “learn to code” programs (code.org, CS First, Khan Academy, Codecademy, Blockly Games, PencilCode, etc.), and an increase in opportunities for K12 students to learn coding in their schools. We have also seen non-profits emerge focused specifically on girls and URMs (Technovation, Girls who Code, Black Girls Code, #YesWeCode, etc.)
    • One of the most positive signals has been the growth of graduates in CS over the past few years.
    Source: 2013 Taulbee Survey, Computing Research Association
    So we are seeing small improvements in K-12 STEM proficiency and undergraduate STEM and CS degrees earned, a significant growth in investment in education innovation, more and more research on the issues of gender and ethnicity in STEM fields and increased opportunities for all students to learn coding skills online, through non-profit programs, through developer boot camps or in their schools.

    However, an interesting, and potentially threatening development resulting from this positive momentum is the lack of capacity and faculty in CS departments to handle the increased number of enrollments and majors in CS. Colleges and universities, as a whole, aren’t adequately prepared to handle the surge in CS education demand - Currently there just aren’t enough instructors to teach all the students who want to learn.

    This has happened in the past. In the 80’s, with the introduction of the PC, and again during the dot-com boom, interest in CS surged. CS departments managed the load by increasing class sizes as much as they possibly could, and/or they put enrollment caps in place and made CS classes harder. The effect of the former was some faculty left for industry while the effect of the latter was a decrease in the diversity pipeline.

    These kinds of caps have two effects which limit access by women and under-represented minorities:
    • First, the students who succeed the most in intro CS are the ones with prior experience.
    • Second, creating these kinds of caps creates a perception of CS as a highly competitive field, which is a deterrent to many students. Those students may not even try to get into CS.”
    -(Guzdial, 2014)

    If we allow the past to repeat itself, we may again find CS faculty leaving for industry and less diversity students going into the field. In addition, unlike the dot-com boom where interest in CS plummeted with the bust, it’s unlikely we will see a decrease in enrollments, particularly in the introductory CS courses. “CS+X”, which represents the application of CS in other fields, is illustrated by the following sample list of interdisciplinary majors in various universities:
    • Yale: "Computer Science and Psychology is an interdepartmental major..."
    • USC: "B.S in Physics/Computer Science for students with dual interests..."
    • Stanford: "Mathematical and Computational Sciences for students interested in..."
    • Northeastern: "Computer Science/Music Technology dual major for students who want to explore connections between..."
    • Lehigh: "BS in Computer Science and Business integrates..."
    • Dartmouth: "The M.D.-Ph.D. Program in Computational Biology..."
    The number of non-major students taking CS courses, particularly the introductory ones, is growing, which makes the capacity issues worse.

    At Google, we recently funded a number of universities via our 3X3 award program (3 times the number of students in 3 years), which aims to facilitate innovative, inclusive, and sustainable approaches to address these scaling issues in university CS programs. Our hope is to disseminate and scale the most successful approaches that our university partners develop. A positive development, which was not present when this happened in the past, is the recent innovation in online education and technology. The increase in bandwidth, high-quality content and interactive learning opportunities may help us get ahead of this challenging capacity issue.


    1Average mathematics scores for fourth- and eighth-graders in 2013 were 1 point higher than in 2011, and 28 and 22 points higher respectively in comparison to the first assessment year in 1990. Hispanic students made gains in mathematics from 2011 to 2013 at both grades 4 and 8. Fourth- and eighth-grade female students scored higher in mathematics in 2013 than in 2011, but the scores for fourth- and eighth-grade male students did not change significantly over the same period. (Nation’s Report Card)

    2The average eighth-grade science score increased two points, from 150 in 2009 to 152 in 2011. Scores also rose among public school students in 16 of 47 states that participated in both 2009 and 2011, and no state showed a decline in science scores from 2009 to 2011. A five-point gain from 2009 to 2011 by Hispanic students was larger than the one-point gain for White students, an improvement that narrowed the score gap between those two groups. Black students scored three points higher in 2011 than in 2009, narrowing the achievement gap with White students. (Nation’s Report Card)
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