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Library Engineering: Students Solving Library Problems: Space Optimization and Inventory Control

Students of Professors Mark Turnquist and Daniel Loucks working with Stacks Manager Catherine Vellake (pictured to the right) have focused on solving practical library problems for Cornell’s Engineering Library in their recent class projects over Fall 1999, Fall 2000, and Spring 2002 in these two courses:
  1. CEE 593 (Engineering Management Methods I: Data, Information, and Modeling)
  2. CEE 594 (Engineering Management Methods II: Managing Uncertain Systems)
These courses focus on modeling and managing systems using these tools:
  • queuing
  • quality control
  • forecasting
  • simulation
  • resource allocation
This exhibit highlights a few of the proposals recommended by the students in the class to address the problems described below.
Photo of Stacks Manager Catherine Vellake

1. Space Optimization and Forecasting

– This library grows by 675 linear feet of shelf space each year

2. Inventory Control

– Shelf reading to find missing books

3. Resource Location

– Finding the best arrangement of books and journals to suit the needs of both public and staff

Space Optimization and Forecasting

Space is a big issues for libraries. Even with the increase of digital collections, the print collection continues to grow. When the shelves are full, what do we do? Where should we allow the most growth room? Here are some suggestions:


1. Move lower-use books to the Library Annex.
The Engineering Library has moved over 70,000 books to the Annex since 1997. A forklift operates there to ensure rapid 24-hour retrieval of any book or journal volume. Articles can be delivered electronically to the desktop. Books are arranged by size, not by call number, for space efficiency.


2. Forecast popular and high-growth areas.
Use a formula that gives usage points for each call number. Checked-out books are rated the highest, then browsed books, then shelves with the most books out of order.


3. Buffer Room
Move the most heavily-used books to Stack 1, which is on the first floor and convenient to all. This is similar to the bookstore model, which places the most popular titles on the most prominent location in the store. This also makes it easier and quicker for those shelving books. Stack 1 could potentially hold 14,940 books. However, this method would make it more difficult to find books overall since the entire stacks would not be in strict call number order.


4. Carrel Clustering
Carrels suffer from poor lighting, not enough space, and are inconvenient to find. By clustering them on Stack 1 or in the Basement (if we removed the microfiche), carrels could provide more space for laptops and small group study.

Other suggestions:
Improve lighting, purchase color copiers, simplify laptop checkouts (and increase the number), include browsing trucks in the stacks to improve efficiency in reshelving.


The Engineering Library has already implemented the following:

  • Installed browsing shelves throughout the stacks so books can be consulted easily, and left for reshelving by staff.
  • Increased the number of circulating laptops and simplified the loan process.
  • Created a pathway on the right (east) wall in Stacks 2 and 3 so it is easier to walk around the shelves as one follows the call numbers, searching for a book. The problem remains on the Basement’s right side.
Graph comparing shelves used vs total shelves in stacks
Current available shelf space in our 4 shelving areas and the extent to which each is occupied.
Bar graph comparing usage of books in stacks
Comparison of the usage of and the number of volumes surveyed in each stack.
Line graph comparing subject area by displacements
Number of displaced books for each subject area over three 2-month intervals.

Inventory Control – Finding Misshelved Books

Students shelf read (scan shelves for out-of-order books) to keep the books in correct call number order and to locate misshelved books. Using the traditional method, each book’s call number is compared to that of the books adjacent to it. Every book is checked, without regard to usage level.

What’s the Shelf-Reading Problem?
It’s tedious work and extremely time-consuming. There are too many shelves (over 7000)!

Traditional Method of Shelf-Reading:
    Average time: 2.24 minutes per 3-foot shelf
    Average number of shelving errors found: 1.18 per shelf
    Time needed to shelfread library by this method: 274 hours (for 7,340 shelves)


Our Goal: Design a procedure which finds 90% of displaced books in half the read time.

What’s Project QuickRead?

  • Project QuickRead was a joint effort between the Engineering Library staff and the students of CEE 593 in the Fall 2000 semester to design a method of library stacks maintenance which optimized available time and resources to find and correct the greatest number of shelving errors in the least amount of time.
  • As implemented, library student employees spend 15 minutes per shift checking 25 to 35 shelves of books for 8 weeks of each term. Once completed, 85% of the entire library has been checked.
  • QuickRead targets high-use call number ranges in the collection instead of trying to cover all 7,340 shelves.
Students scan only the first half of the call number, instead of the entire 5 to 6 lines. This makes the process faster and less tedious. Tests show that Quickread find 83% of the shelving errors, and catches all misshelved books whose correct location is several aisles away – the most troublesome errors for patrons and staff.
Line graph displaying displaced books found for all call numbers
Number of displaced books found using QuickRead.

“Though QuickRead does not find every misshelved book, the real value of the method is its ability to cover far more shelves than conventional reading methods.”

– Catherine Vellake, Stacks Supervisor

Resource Location – What’s the Best Way to Arrange the Collection?

Digitized sketch for roadmap of Engineering Library

Stacks are in A-Z order (Library of Congress Classification System is used).


To make the books and journals easier to find, breaks are made at the end of each floor in a “clean” spot, such as A-Q, not A-QA 76.6.


However, this concentrates the most heavily used books in the basement and costs 217 shelves overall. To the left is a diagram of what we have. Is this the best way?

Questions and comments are welcome to
Designed by Jill Powell and Catherine Vellake