Preferred Infrastructure Inc.

Corporate Profile

Japanese Page here


  • Company Name:  Preferred Infrastructure Inc,
  • Founded: March 2006
  • CEO:  Toru Nishikawa
  • Number of Employees: 28
  • Location: 2-40-1 Hongo, Tokyo, Japan
    (near Hongo Campus, University of Tokyo)
  • Email:
  • Business: Software Development & Licensing
    Search Engine & Recommendation System

Our Goals

  • To put the cutting-edge research results in the academic world to practical use as soon as possible.
  • To challenge the most difficult problems and provide solutions to them.


  • CEO: Toru Nishikawa Computer Science,
    University of Tokyo ACM International Collegiate Programming Contest 2006 19th place
  • VP: Daisuke Okanohara
    Ph.D Computer Science, University of Tokyo
    Exploratory IT Human Resources Program sponsored by IPA Japan (2002 – 2005)
  • Many of other members have also achieved outstanding results at several programming contests.


  • Information Retrieval
  • Recommendation
  • Natural Language Processing
  • Machine Learning
  • Data Compression
  • Database System
  • Very Large Distributed System
  • Bioinformatics

Main Customers


Sedue – Comprehensive search platform which combines search and recommendation technologies

Sedue Search Engine

  • Supports many types of indexing methods, and ranking methods
  • Linear Scale-Up
    Verified up to 128 threads on a Sun box
  • Easy Scale-Out
    Indexer and searcher nodes can be added without stopping the system.
  • High Reliability
  • Customizable Ranking Feature
  • Applications: Web Search, Document Search, Enterprise Search, Text Mining

Jubatus – Distributed online machine learning framework


  • Online multi-class/binary classification
  • Online linear regression
  • Online recommendation with inverted index or LSH (locality sensitive hash)
  • Framework for online machine learning with fault tolerance