Monday, November 05, 2012

Markov's take on Teaching



"The alleged opinion that studies in seminars [in classes] are of the highest scientific nature, while exercises in solving problems are of the lowest [rank], is unfair. Mathematics to a considerable extent consists in solving problems, [and] together with proper discussion, [this] can be of the highest scientific nature while studies in ... seminars might be of the lowest [rank]."
Source: http://www.sciencedirect.com/science/article/pii/S0024379504000357

Sunday, July 01, 2012

NIST Bigdata workshop


Facebook generates user logs of size 130TB/day and pictures of size 300TB/day. Google generates >25PB/day of processed data.  Bigdata is about storage, processing and analysis of large amounts of data.

In this NIST organized one and a half day bigdata workshop, many stalwarts of computing along with other industry representatives came together to present and discuss the current infrastructure, technology and solutions in the bigdata space. Several people were invited to give talks (http://www.nist.gov/itl/ssd/is/upload/BIG-DATA-Workshop-may25.pdf ) Talks that I found interesting in the workshop were given by these people:

Ian Foster is a Distinguished Fellow and the Associate Division Director in the Mathematics and Computer Science Division at Argonne National Laboratory, where he leads the Distributed Systems Laboratory. He is known as the ‘father of the grid’. He described the Globus(GT) project that has been developed since the late 1990s to support the development of service-oriented distributed computing applications and infrastructures. Core GT components address, within a common framework, basic issues relating to security, resource access, resource management, data movement, resource discovery, and so forth. These components enable a broader “Globus ecosystem” of tools and components that build on, or interoperate with, core GT functionality to provide a wide range of useful application-level functions. These tools have in turn been used to develop a wide range of both “Grid” infrastructures and distributed applications.
                                

M Stonebraker (developer of the Postgres RDBMS, former CTO of Informix, founder of several database startups) is a professor of Computer Science at MIT. Stonebraker has been a strong critic of the NoSQL movement and suggests that Hadoop based systems are a ‘non-starter’ for bigdata scientific problems. Hadoop based systems are only useful for embarrassingly parallel computations (such as parallel grep)
Stonebraker primarily talked about his efforts and involvement with two projects, VoltDB (commercial startup) and SciDB (open-source scientific database system). 

                                                             (Age of Data; source: VoltDB)

In the graphic above, time is represented on the horizontal axis. To the far left is the point at which data is created. The “things” we do with data are strongly correlated to its age and some usecases are shown above. Just after data is created, it is highly interactive. We want to perform high velocity operations on that data at this stage – how fast can we place a trade, or serve an ad, or inspect a record? Shortly after creation, we are often interested in a specific data instance relative to other data that has also arrived recently – this type of analytics is referred to as real time analytics. As data begins to age, our interest often changes from “hot” analytics to record-level storage and retrieval – store this URL, retrieve this user profile, etc.
Ultimately data becomes useful in a historical context.  Organizations have found countless ways to gain valuable insights – trends, patterns, anomalies – from data over long timelines.  Business intelligence, reporting, back testing are all examples of what we do to extract value from historical data. 


The above graphic (source: VoltDB) shows different technologies being used today for different types of application usecases for data value chain. 

VoltDB (100x of standard SQL) is a blazingly fast in-memory relational database management system (RDBMS) designed to run on modern scale-out computing infrastructures. VoltDB is aimed at a new generation of high velocity database applications that require:

·         Database throughput reaching millions of operations per second
·         On demand scaling
·         High availability, fault tolerance and database durability
·         Realtime data analytics

SciDB  is a new open-source data management system intended primarily for use in application domains that involve very large (petabyte) scale array data; for example, scientific applications such as astronomy, remote sensing and climate modeling, bio-science information management, as well as commercial applications such as risk management systems in the financial services sector, and the analysis of web log data. SciDB is not optimized for online transaction processing (OLTP); it only minimally supports transactions at all. It does not provide strict atomicity, consistency, isolation, and durability (ACID) constraints. It does not have a rigidly-defined, difficult-to-modify schema. Instead, SciDB is built around analytics. Storage is write-once, read-many. Bulk loads, rather than single-row inserts, are the primary input method. "Load-free" access to minimally-structured data is provided.

Stonebraker mentioned applications such as high frequency volume trading, sensor tagging, real time global position assembly as right candidates for database oriented bigdata problems. These data are good for cases involving pattern finding in a firehose, complex event processing, real time complex high performance OLTP as well as data with ‘Big Variety’ (see Daniel Bruckner and Michael Stonebraker. Curating Data at Scale: The Data Tamer System)

Michael Franklin is a Professor of Computer Science at UC Berkeley, specializing in large-scale data management infrastructure and applications. He is the director of AMPLab (See overview slides here: http://www.scribd.com/doc/58637242/ ) at UCB.
Some bigdata projects and systems he mentioned:
Bigdata processing - pregel, dryad, hadoop, M, hbase, mahout, hypertable, cassandra
Bigdata interfaces: Pig, Hive
AmpLab projects leveraging hadoop for complex bigdata problems:
Spark – Scala based
Shark – Spark + Hive - lots of caching for performance gains for iterative machine learning algorithms on big data
He also mentioned AMPCamp being organized on Aug 21- 22 in Berkeley – hands-on tutorial for Shark, Spark and Mesos, machine learning, crowd sourcing overviews, apps and usecases
Kirk Borne (George Mason univ) themed his talk around the following:
-       characterize the known (clustering, unsupervised)
-       assign the new (classification, supervised learning)
-       discover the unknown (outlier, semi-supervised learning)

Dennis Gannon, Microsoft Research described about their 100 globally dist. data centers, 8-9 public data centers with 1M servers each, their International Cloud Research Engagement Project for applications such as Realtime traffic analysis and democratized access to big data. He also described Microsoft’s SAAS based solution competing with mapreduce/hadoop called Daytona and the datamarket build around it.
He also mentioned about their efforts to leverage bigdata and cloud support for MS Excel (some free plugins on MSR site for working with bigdata directly on Excel!)
Joseph Helerstein, Computational Discovery Department, Google described ‘Google Exacycle’ project for Visiting Faculty giving away 1 billion core-hours for researchers (10 numbers)
Mark Ryland, Chief Solution Architect, Amazon Web Services gave some very cool demos demonstrating quick setup and processing for bigdata problems on Amazon’s cloud infrastructure. He mentioned things such as:
-       Taser – by Police Dept for video storage on the cloud using AWS infrastructure
-       S3, EC2, Relational Data Service infrastructure
-       DynamoDB  - NoSQL 100Ks of IO/s
-       Amazon Elastic MapReduce (EMR) (used by Yelp - 400 GB of log data per day)
-       1000 genome project - Federal Govt initiative
-       BioSense 2.0
-       Coursera site running on AWS
-       NYU Langone project

Charles Kaminski, Chief Architect, LexisNexis also demonstrated their cloud infrastructure for bigdata problems. (http://aws.hpccsystems.com) He mentioned LexisNexis projects for scientific computing such as:
-       thor - data crunching
-       roxie - key-value store + complex data process
-       ECL language - transformative data graph used for setting up workflows for thor and roxie

Ed Pednault, CTO , Scalable Analytics, Business Analytics and Math Sciences, IBM Research also mentioned very interesting bigdata work happening at IBM.