LIBRARY OF THE UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN 510.84 IJKor no. 764-7^9 cop. Z 80V 3 1977 1 / tftCI APR 3 Wit* •/> L161 _O-1096 Digitized by the Internet Archive in 2013 http://archive.org/details/dispatchingfiret764adam 3 / V C 7 UIUCDCS-R-75-76 l 4 <■'■: DISPATCHING FIRE TRUCKS WITH THE AID OF A COMPUTER by Hugh William Adams, Jr. December, 1975 DEPARTMENT OF COMPUTER SCIENCE UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN URBANA, ILLINOIS ZHEUBRARYOFTHE MAR 2 1976 UNIVERSITY.QF ILLINOIS ' UIUCDCS-R-75-76 1 + DISPATCHING FIRE TRUCKS WITH THE AID OF A COMPUTER by Hugh William Adams, Jr. December, 1975 This work was supported in part by the Department of Computer Science and the Communications Division of Motorola and was submitted in partial fulfillment for the Master of Science degree in Computer Science, 1975- ... PREFACE This thesis describes a computer system for dispatching fire trucks. It is not a detailed report of the actual system but rather a description of the initial design. IV TABLE OF CONTENTS CHAPTER PAGE I. INTRODUCTION 1 II. EXISTING METHODS OF DISPATCHING FIRE TRUCKS . '. 2 III. GOALS TO BE ACHIEVED BY USE OF A COMPUTER ... 5 IV. DESIGN CONSIDERATIONS 6 V. ACTUAL DESIGN 8 VI. IMPLEMENTATION 10 APPENDIX 11 I. INTRODUCTION The purpose of this thesis is to describe the design of a com- puter system to dispatch fire trucks. The system is being designed for the New Orleans Fire Department with the intention of using it as a basis for computer systems for other fire departments. This document is divided into three sections. The first section is a description of the methods currently used to dispatch fire trucks without the use of a computer. The second section is an investigation of how a computer system can be used to increase efficiencies, reliability, and to decrease truck responding time. The third section is a general overview of the actual design and implementation of the computer system, including both hardware and software considerations. For the reader who desires more details, a list of the documents containing the detailed design of the software modules used is included in this section. II. EXISTING METHODS OF DISPATCHING FIRE TRUCKS Complaints are received at the dispatch center either by tele- phone call or by a light on a board that indicates that an alarm is being issued by an alarm box. If the complaint is by telephone, the address of the fire is given. This address may be either a street name and number, two cross streets, or a public building or common place name. An address card file of streets and common place names is then manually searched. The address card contains a zone number, the nearest cross street, a suggested initial fire response plan, and the number of an assignment card for response plans beyond the initial response. If the alarm is from an alarm box it may either be from one of several security companies' boxes or from a public fire box. As in the case of the address file, there is a file for each type of alarm box. The appropriate file is searched for the card corresponding to the box. This card contains any pertinent information about the fire, suggested initial fire response plan, and an assignment card number for responses beyond an initial response. The dispatcher must now attempt to formulate an initial response to the fire. He uses the sugqested engines on the retrieved card, the current status of each engine, and the type of fire to devise this initial response. The dispatcher then radios the engines allocated for the fire. The location of the fire, the nearest cross street, the type of fire, and location premise information is broadcast to the engines and fire house. Premise information includes the type of building, location of inflammable materials, the presence of guard dogs, location of hydrants, and associated pertinent information. After the initial response to the fire, the dispatcher searches the assignment card file for the assignment card identified on the ini- tial card. The assignment card contains the engines and units used when a fire is judged severe enough to require additional units. The assign- ment card also contains engines to be moved from other fire houses to this fire house to replace the dispatched engines. Engines are moved up to provide additional strength for the current fire and adequate pro- tection for the zone in the event of a second alarm. The dispatcher then notifies the move up engines to cover for the fire house. He then waits for a response from the units at the fire to determine if additional units are required. If more units are re- quired, he dispatches the current move up engines and assigns other units to cover the dispatched units. This process continues until the fire is under control. The dispatcher then reverses the process and returns engines to their original fire houses as they become available. Although activity at the dispatch center may become quite hectic during a fire, the center is normally quiet. A large fire department may only receive one complaint within a twenty-four hour period. This is unlike police departments with high activity, since several telephone calls reporting the same incident are not treated by the operators as a separate incident. Several problems exist with this method of dispatching fire trucks. The first and most obvious problem is that manually searching the street address or alarm card file increases the response time be- tween complaint reception and engine dispatchment. This increased re- sponse time can result in possible danger to human life and extensive property damage. Insurance companies also recognize this fact since one of the factors they use in determining insurance rates is the re- sponse time. Another inherent problem is that card files must be kept to a reasonable size to allow manual searching. This means that premise in- formation for a given location must be brief or the file would grow too large. Difficulties are also found in radio communication between the dispatcher and the units. A great deal of excitement is present when trying to respond quickly that may cause a misinterpretation and while enroute to the fire, the noise of the siren impairs radio communication. Thus units experience frequent trouble receiving all the information broadcast to them. III. GOALS TO BE ACHIEVED BY USE OF A COMPUTER If a printer control terminal (PCT) is interfaced to a com- puter it can control teleprinters mounted in the fire trucks and fire house. The operator can then quickly broadcast accurate information to the fire trucks without interference since each truck will receive a hard copy of the information. On-line computer files of street addresses, common place names, assignment cards, and alarm cards will reduce response time as the card files need not be manually searched. In addition, when the cards are displayed, the status of each unit on the card can be indicated to the operator. These on-line cards may also be altered and stored as temporary cards. Thus the operator is provided with a scratch pad to reflect changes due to assigning move up units. Finally, a report of each incident can be generated and stored on some medium such that it may be examined by supervisor personnel at a later time. This report can also be used by insurance companies to deter- mine fire insurance rates for an area. IV. DESIGN CONSIDERATIONS System hardware must include ample fast access file space to support the card files and the address data base. The file medium must be fast enough to provide a retrieval time satisfactory for the customer needs. In addition, this system may be expanded to include police vehicle dispatching. Thus the system configuration may be ex- panded and more file space required. There must also be a means of moving copies of the on-line files to another device for storage. This backup copy will be required in the event of a system failure that may destroy the current on-line files. Software design of this system must consider the available software modules designed for use in other dispatching systems. Use of existing modules greatly reduces the time to design and test a new cus- tomer system. There are two data base managers that are currently being used in other systems; a hierarchical data base manager used to return a police beat number for a given street address, and a data base manager to handle fixed length records not exceeding one sector in size (512 bytes) . The system software will be of modular design. This means that there will be a specific module for each given function in the sys- tem. Thus there will not be a duplication of code. The system is in- tended to be marketed as a standard product, that is sold to a new customer with minimum modification. With modular software, only a few modules performing a given function will be modified for each change a customer requires. Two other advantages to the modular design is that it requires less time to debug a system and another programmer can learn the system more quickly. These advantages are due to the fact that once a module is debugged or understood there is no need to be concerned about the module whenever a function calls it. The hardware configuration, commands, and file structures of the system are all described by a series of tables. Thus these items can be added to or deleted from the system without changing the actual code used to execute the system. V. ACTUAL DESIGN The system requires four, 2.1 million byte disk drives. Each drive will contain only one type of information so that if a drive fails it may be possible to run a limited system. The system tasks, alarm card files, street data base, and premise information reside on separate drives. There may be one or more CRTs on the system used as dispatching terminals. These CRTs functionally accept operator commands and display data. A magnetic tape transport is used for off-line backup storage of files and as a device for on-line reports. The printer control termi- nals and teleprinters are used to provide a hard copy of information on a fire location. Finally, a teletype is used to input commands to ini- tialize the system, log data base updates, provide a hard copy of sys- tem alarm messages, and prepare paper tape for printer control terminal broadcast for times when the system is down. The street address data base can be structured in a hierarchical form allowing the hierarchical data base manager to be used for the data base. The alarm cards are all fixed length and all cards except assignment cards are less than 512 bytes. Therefore the assignment card is divided into two parts, each less than 512 bytes and the fixed length data base manager is used to support the card files. The premise information file presents a problem because the records are variable length and logically grouped in 360 byte blocks. The fixed length record data base manager cannot be used. The large record size causes either overflow or slow response times for the hierarchical data base manager. Therefore a separate file handler must be designed for the premise information. Operators at the dispatch CRTs will be able to retrieve and display information for an address or alarm card and to broadcast in- formation to fire trucks' teleprinters. The commands to update the data base require a password before accepting the request. This pass- word requirement is based upon the knowledge that operators "tinker" with the system during idle periods. If unnecessary data base changes are implemented, the data base may be accidently altered or transformed into an unoptimal form. Also, the password insures that only qualified personnel initiate data base changes. 10 VI. IMPLEMENTATION Due to the application involved, the critical factor of the system is operator request response time. The goals of less than two seconds from the time of entry of an address to the display of data, and less than one second from entry of a broadcast command to the start of teleprinting have been established. The response time can only be eval- uated with full system data base in an operating environment. Since the hierarchical data base manager is used, the time required to display ad- dress data can be estimated by examining the response time in the police system. This time has been found to be less than two seconds. Hence it appears this goal is achievable. There are no previous applications using teleprinting. Thus the other goal of less than one second to start of teleprinting cannot be estimated using this method. The system has been designed to attempt error recovery. If an error occurs during a file update, an attempt is made to restore the file to its state before the update. If the file is destroyed, the mag- netic tape file is used to restore the disk copy. When a system error is detected, the task in which the error occurred is reloaded from the system task disk. If this fails, then the entire system is halted and reloaded from the system disk. In the event the system disk is destroyed, it is reloaded from magnetic tape as in the case of a data base. 11 APPENDIX A. Sample Operator Command The following text is taken from the customer's operators manual. It describes one of the twenty-eight dispatch commands available to the operators at their CRTs. The description is included to give the reader some idea of the operation of the system. BN (XMIT) Used to enter a street address as a key to the assignment card. The command is entered and the format shown in Figure 1 is displayed. The operator enters the street number and name; or intersecting streets; or the common place name, and optionally the fire type. The operator then enters the transmit function and the processor reads the information on Line 1, converts the address to an assignment card, and places on the CRT the display shown in Figure 2. The information shown in Lines 5 and 7 are as entered, Line 6 is provided by the street-to-fire district module. It includes the cross street associated with that street address, the zone number, and the as- signment card. Lines 9 through 19 show the assignment card. Information on a line starting with an asterisk indicate move-up data. Lines 20 through 24 are used to display possible premise information. 12 The operator may edit the information displayed prior to trans- mission to the processor. After editing the data he places the cursor at the character position after the last character to be transmitted. He enters the transmit function and the processor accepts the information for transmission to the PCT. The text is preceded by one line containing the time and is followed by one line of blanks. Figure 3 shows the data as it would appear on the teleprinter if the cursor is placed after the 302 on Line 9. When intersecting street names are to be entered the street number is left blank and the street names are entered in alphabetical order. Proper names are entered in the second street name field. The street address is returned and displayed on Line 5 with the common name displayed on Line 4 of Figure 2. Premise information is displayed on lines 20 through 24, as shown in Figure 2. This information is formatted for transmission to the teleprinter. A maximum of 360 characters may be displayed (10 lines of 36 characters each). The end of text for premise information is marked with the character "<". This prevents transmitting unnecessary blanks. The situation where premise information is not being transmitted the symbol "<" is placed after the last character (of the vehicle number) to be transmitted. This method might be used in multiple alarms. 13 on C5 CQ i — CMOI^LD^r-^COCTi Oi — c\joo^-Lr>(£>r--coo~>Oi — c\j m «3- -,— r-i— r— i— i— i— i— CM CMCMCVJ CM 14 oo I I I 3Z oo I — ( CO CO CvJ o oo oo o oo co o oo o: UO o <: C\J o C\J I rvi i o o oo co > oo ui dz ui a: oo ZLUm - i— X h- CvJ vO O r— OO UJ O CsJ CvJ O O O OO I OO o UO OO O oo * o oo I VO O OO * CvJ UJ Dd i— i— vo CvJ LU UJ CO UJ I i— UO i— .— OO i— I * I i— CsJ OO CsJ VO I «=t CvJ CTi O UJ O OO OO UO CnJ O UJ CvJ UJ O I UO O f— It * ^j- ui I «3- I -K OO C\J I co CvJ en o CvJ O VO I CvJ CvJ CvJ I <* uo CvJ I— * CvJ o o ui vo I — I O oo CvJ * oo o * «3" Ul I ^T OO r— O i— I i — r-» * I r— ■=3" * V OO I UO UO OO UO I UO 00 * —> o 2: O vO OO 1— CvJ UO 31 00 00 * •• CvJ Q£ UI «^- UI VO o 00 N* CO 1— o Ul UO CO I I — I — I .— r— ^. 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My Contribution With the exception of the hierarchical data base manager (done by another person and me) and the New Orleans Functional Specification (done by the customer, the sales representative, and me) all of the above software modules were design and implemented solely by me. BIBLIOGRAPHIC DATA SHEET 1. Report No. UIUCDCS-R-75-76U 3. Id c ipient's \< 1 1 ■.•. 1 m Ni J. I 11 Ic and Sunt it lc- Dispatching Fire Tracks with The Aid of a Computer 5. Report Dale November, 1975 '. Auihor(s) Hugh William Adams, Jr. 8- Performing Organization I | No. ). 1' rtttrtning Organization Name and Address Department of Computer Science University of Illinois Urbana, Illinois 10. Project/ fask/ \X..ik Unit \ 1 1. ( Contract /dram Ni see below 12. Sponsoring Organization Name and Address Communications Division of Motorola and Dept. of Computer Scien* L300 Algonquin Road University of Illinois tehaumburg, Illinois Urbana, Illinois 13. Type of Report & Peri. Covered Masters Thesis 14. ipplementary Notes (S \ b s r ra c t s As technology advances, public safety organizations are seeking means to apply these advances to improve their efficiency. This report describes the methods currently used to dispatch fire trucks in a large city. It then examines how a computer can be used to aid the fire department. The investigation described has been implemented and is currently used by the New Orleans Fire Department. Key Words and Document Analysis. 17o. Descriptors computer aided dispatching fire trucks 7b. Identifiers Open-Ended Terms 1. Contract/ Grant No. New Orleans Fire Department Computer Aid Dispatching System Contract with Motorola Inc. 7c. ( OS ATI Fie Id /Group i Availability Statement 1 "••" N T'S- 35 (10-70) 19. Security Class (This Report) UNCLASSIFIED 20. Security Class (Th Page UNCLASSIFIED 22. USCOMM-DC 4 3 2 9-