Introduction to Software Engineering Week 1: Case studies

Transcription

1 Introduction to Software Engineering Week 1: Case studies Nguyễn Thị Minh Tuyền Adapted from slides of Ian Sommerville

2 Case studies A personal insulin pump An embedded system in an insulin pump used by diabe8cs to maintain blood glucose control. A mental health case pa1ent management system A system used to maintain records of people receiving care for mental health problems. A wilderness weather sta1on A data collec8on system that collects data about weather condi8ons in remote areas. 2

3 Insulin pump control system Collects data from a blood sugar sensor and calculates the amount of insulin required to be injected. Calcula1on based on the rate of change of blood sugar levels. Sends signals to a micro- pump to deliver the correct dose of insulin. Safety- cri1cal system as low blood sugars can lead to brain malfunc1oning, coma and death; high- blood sugar levels have long- term consequences such as eye and kidney damage. 3

4 Insulin pump hardware architecture Insulin reservoir Needle assembly Pump Clock Sensor Controller Alarm Display1 Display2 Power supply 4

5 Activity model of the insulin pump Blood sensor Analyse sensor reading Blood sugar Compute insulin Insulin log Insulin dose Insulin pump Control insulin pump Pump data Compute pump commands Log dose 5

6 Essential high-level requirements The system shall be available to deliver insulin when required. The system shall perform reliably and deliver the correct amount of insulin to counteract the current level of blood sugar. The system must therefore be designed and implemented to ensure that the system always meets these requirements. 6

7 A patient information system for mental health care A pa1ent informa1on system to support mental health care is a medical informa1on system that maintains informa1on about pa1ents suffering from mental health problems and the treatments that they have received. Most mental health pa1ents do not require dedicated hospital treatment but need to aeend specialist clinics regularly where they can meet a doctor who has detailed knowledge of their problems. To make it easier for pa1ents to aeend, these clinics are not just run in hospitals. They may also be held in local medical prac1ces or community centres. 7

8 MHC-PMS The MHC- PMS (Mental Health Care- Pa8ent Management System) is an informa8on system that is intended for use in clinics. It makes use of a centralized database of pa8ent informa8on but has also been designed to run on a PC, so that it may be accessed and used from sites that do not have secure network connec8vity. When the local systems have secure network access, they use pa8ent informa8on in the database but they can download and use local copies of pa8ent records when they are disconnected. 8

9 MHC-PMS goals To generate management informa1on that allows health service managers to assess performance against local and government targets. To provide medical staff with 1mely informa1on to support the treatment of pa1ents. 9

10 The organization of the MHC-PMS MHC-PMS local MHC-PMS local MHC-PMS local MHC-PMS server Patient database 10

11 MHC-PMS key features Individual care management Clinicians can create records for pa8ents, edit the informa8on in the system, view pa8ent history, etc. The system supports data summaries so that doctors can quickly learn about the key problems and treatments that have been prescribed. Pa1ent monitoring The system monitors the records of pa8ents that are involved in treatment and issues warnings if possible problems are detected. Administra1ve repor1ng The system generates monthly management reports showing the number of pa8ents treated at each clinic, the number of pa8ents who have entered and lem the care system, the drugs prescribed and their costs, etc. 11

12 MHC-PMS concerns Privacy It is essen8al that pa8ent informa8on is confiden8al and is never disclosed to anyone apart from authorised medical staff and the pa8ent themselves. Safety Some mental illnesses cause pa8ents to become suicidal or a danger to other people. Wherever possible, the system should warn medical staff about poten8ally suicidal or dangerous pa8ents. The system must be available when needed otherwise safety may be compromised and it may be impossible to prescribe the correct medica8on to pa8ents. 12

13 Wilderness weather station The government of a country with large areas of wilderness decides to deploy several hundred weather sta1ons in remote areas. Weather sta1ons collect data from a set of instruments that measure temperature and pressure, sunshine, rainfall, wind speed and wind direc1on. The weather sta8on includes a number of instruments that measure weather parameters such as the wind speed and direc8on, the ground and air temperatures, the rainfall over a 24- hour period. Each of these instruments is controlled by a somware system that takes parameter readings periodically and manages the data collected from the instruments. 13

14 The weather station s environment «system» Weather station «system» Data management and archiving «system» Station maintenance 14

15 Weather information system The weather sta1on system This is responsible for collec8ng weather data, carrying out some ini8al data processing and transmisng it to the data management system. The data management and archiving system This system collects the data from all of the wilderness weather sta8ons, carries out data processing and analysis and archives the data. The sta1on maintenance system This system can communicate by satellite with all wilderness weather sta8ons to monitor the health of these systems and provide reports of problems. 15

16 Additional software functionality Monitor the instruments, power and communica1on hardware and report faults to the management system. Manage the system power, ensuring that baeeries are charged whenever the environmental condi1ons permit but also that generators are shut down in poten1ally damaging weather condi1ons, such as high wind. Support dynamic reconfigura1on where parts of the sojware are replaced with new versions and where backup instruments are switched into the system in the event of system failure. 16