december 13, 2004 1 statag prototype presentation daniel tubbs brian easton jason sadler latricia...

December 13, 2004 1

STATag

Prototype Presentation

Daniel Tubbs Brian Easton

Jason Sadler Latricia Simon

Chad Hilton James Mayor

December 13, 2004 2

Societal Problem Defined

Hospital staff waste time locating mobile equipment, wasting billions of dollars annually.

35-60%1 of a nurse’s time is wasted on Searching for equipment Clarifying orders Entering redundant information

Wasting $58 - $99 billion annually2

December 13, 2004 3

Solution

The use of STATags will Reduce man hours searching for needed equipment Increase staff efficiency

Increase a nurse’s efficiency at least 10%1

Lower operating costs Save a real $1 for every $4 of efficiency gained3

(reduction of overtime, increased turnaround) Increase job satisfaction3

December 13, 2004 4

STATag Goals Use dead-reckoning to determine current

location Use network security Use a self-discovering and self-configuring

network Handle large quantities of equipment

December 13, 2004 5

STATag Goals (continued)

Activate alarms Store historical location and usage data Run without intervention for long periods

Battery must last 5-7 years Need calibration only when battery is changed

December 13, 2004 6

STATag Limitations

STATag will not: Prevent theft Collect or transmit personally identifiable

health information (covered under HIPAA) Communicate further than 100 feet between

STATags

December 13, 2004 7

STATag System

DB ServerNetwork Coordinator

User

Internal Webserver

Database

`

Web Browser

STATag

STATag

STATag

STATag

STATag

December 13, 2004 8

Web Server / User Interface


User

Internal Webserver

Database

`

Web Browser

STATag

STATag

STATag

STATag

STATag

December 13, 2004 9


User

Internal Webserver

Database

`

Web Browser

STATag

STATag

STATag

STATag

STATag

Database

December 13, 2004 10

STATags


User

Internal Webserver

Database

`

Web Browser

STATag

STATag

STATag

STATag

STATag


Web Server

Open source web server Provides a bridge between the end user and

the database Eliminates the need for client software Allows any client with a web browser to

connect PC Laptop PDA


Database

Open source relational database collects and stores STATag location information Real-time look-ups History Alarms Inventory Reports


STATag Diagram

Microcontoller

802.15.4 Module

Flash RAM (1MB)

Usage Module(In use switch)

Movement Detection Module(Accelerometers &

Gyroscopes)

Tamper Detection Module

(Tag Removed Switch)

Battery


STATag

Accelerometers and gyroscopes detect orientation and motion

Microcontroller calculates current position 802.15.4 module communicates to DB server

via mesh network Switches provide state information RAM records position data when unable to

communicate with DB server Battery keeps everything running for 5 years


Project Risks – Web Interface

Inadequate response time Complexity of use Complexity of administration


Project Risks - Database

Database size may grow too fast Database design may be too complicated to

use without regular administration Response time may be inadequate for a large

number of tags


Project Risks – STATag Interference with hospital monitoring equipment

STATag transmits 1% the power of other safe wireless devices

Most major hospitals are implementing WiFi Conflicts with other 2.4 GHz networks

802.15.4 has been designed for interoperability 802.15.4 and ZigBee are new standards and

therefore there may be unknown issues Hardware issues are being resolved by manufactures Software issues will be correctable by patching


Prototype Goals

Build a prototype for each subsystem Demonstrate integration of the subsystems

Web server and user interface Database Individual STATag


Prototype Diagram

DB Server

802.11 Network

User

Internal Webserver

Database

`

Web Browser

Laptop

Dead Reckoning Module

Live Position Data

Simulated Position Data


Prototype vs. Real System

Prototype Real System

Database MSSQL MySQL

Web Server IIS 5.1 Apache

User Interface ASP.NET Java

Web Browser Any Any

Hardware Same PC Separate

Servers


Prototype vs. Real System

Prototype Real System

Accelerometer 2-axis 3-axis

Microcontroller Laptop On-board

Wireless Network 802.11b 802.15.4

RAM Log File On-board

Gyroscope No 3-axis

In-use Switch No Yes

Tag-removed Switch No Yes


Database Accomplishments

Each STATag history entry requires 40 bytes Average hospital database size – 67.2 GB

(1 year history of 1368 tags updated every 30 seconds)

Database design is simple


Database Schema

history

PK timestampPK,FK1 statag_id

pos_x pos_y pos_z in_use

id_sn

PK statag_id

FK2 serial_num removed

statag_region

PK region_idPK,FK1 statag_id

active

region

PK,FK1 region_idPK,FK1 statag_id

north south east west top bottom

sn_type

PK serial_num

FK1 type_num

description

PK type_num

description


User Interface / Database Demo


STATag Prototype

ADXL202EB-232 2-axis accelerometer evaluation board with serial interface

Custom application calculates position data from log file created by ADXL202EB-232

Position data sent to database server via 802.11b network


ADXL202EB-232


ADXL202 Surface Mount Package


STATag Demo

Acceleration (a) Measured by accelerometer

Speed (s) sfinal= sinitial + a * time

Position (p) pfinal= pinitial + s * time


Issues Encountered

Minimum error - 0.0002 g 5-year cumulative error – minimum of 95

miles per axis Location uncertainty

Prototype - 9,025 square-miles Production - 860,000 cubic-miles

Maximum allowed error - 1.91 x 10-9 g

(5 ft. error after 5 years)


Position Uncertainty After 5 Years


Five-year Error vs. Max. Error

504,922252,461

126,23063,115

31,55815,779

7,8893,945

1,972986

493247

12362

3115

84

1

10

100

1000

10000

100000

1000000

Maximum Allowed Error (g)

Cu

mu

lati

ve E

rro

r (f

t)


Detected Acceleration by Angle

0

10

20

30

40

50

60

70

80

90

100

0 4 8 12

16

20

24

28

32

36

40

44

48

52

56

60

64

68

72

76

80

84

88

Degrees

De

tec

ted

Ac

ce

lera

tio

n (

%)


Final Prototype Diagram

DB Server

User

Internal Webserver

Database

`

Web Browser

Laptop

Dead Reckoning Module

Simulated Position Data


Options

Continue working with Analog Devices to find an accelerometer / software combination that meets our design needs

Replace the dead-reckoning functionality with Real-Time Locating Systems (RTLS) components

Both options affect only the STATag subsystem and remaining subsystems remain the same


Continue with Dead-Reckoning

PRO Costs and profits are well understood Progress already being made

CON May not be able to solve issues May require additional manpower or funding


Switch to RTLS

PRO Commercial off the shelf product Standardized, multiple vendors Not affected by cumulative error

CON Higher wireless transmitting power Increased hospital installation cost Delayed hospital ROI


Recommendations

Move forward with database, web server, and user interface development

Convert STATag to use RTLS components


Questions?


References & Calculations

1 Cindy Jimmerson, April 7, 2004

2 $166 Billion (Nurse’s Salary and Benefits)4 x 35% = $58 Billion

$166 Billion (Nurse’s Salary and Benefits)4 x 60% = $99 Billion

3 Murphy, Mark: Eliminating Wasteful Work in Hospitals Improves Margin, Quality, and Culture


References & Calculations

4 975,9625 Beds x 10 Mobile Medical Devices per bed = 9.76 Million Mobile Medical Devices

5 Hospital Statistics, 2004 edition, American Hospital Association, as reported by the American Hospital Association website

december 13, 2004 1 statag prototype presentation daniel tubbs brian easton jason sadler latricia...

Documents

nurses time

web server user interface

staff efficiency

nurses efficiency

subsystemsweb server

end user

mobile equipment

needed equipment