Basics of System Reliability Analysis - ReliaWiki
Complex electronic systems can be difficult to design, understand and test. To describe the subsystems or modules in a complex system, block diagrams are. Relationships Between Subsystems, Hierarchies, Control Groups and Tasks. Remember that system processes are called tasks in cgroup terminology. An organization is composed of subsystems and systems which are embedded in will be placed on the relationships between three subsystems (educational.
We can add this to the diagram by showing customer complaints as a sub-subsystem within the box for Customer Relations. The rest of Customer Relations would make a small internal profit without it as shown by the light green background in the rest of the Customer Relations box. On the surface, this looks like a perfectly sensible approach, and there will almost certainly be ways of presenting it to senior management with costings that make it look more cost-effective than the current system.
In reality, as every departmental head around that lunch table will know, this is a recipe for disaster. Under this new system, every department will now need to train up at least one member of staff in handling customer complaints. It will also cost time; a staff member handling a complicated customer complaint will have to take time away from their work on design, or whatever their normal role is.
What is subsystem? definition and meaning - avesisland.info
In addition, it will cause conflict and chaos, because each department will try to pass the problem over to a different department. Design will claim that the design was fine, but that the marketing material gave an inaccurate description of what the product would do, so they pass the complaint on to Marketing.
With each hand-over, the customer is getting more irate, leading to a worse public perception of the company as a whole. That now appears in each of the other departmental boxes, as a small red box.
Previously, the company only paid that fixed cost once, for Customer Services. Now, the company is having to pay it six times. In addition, the company is having to absorb the costs of internal buck-passing, as complaints get shuffled from one department to another the second set of small red boxes in addition to actually resolving the complaint the third set of small red boxes.
The result looks something like this. The overall result is that three departments will manage to show modest internal profits, including Customer Relations, but the company as a whole ends up with higher internal costs, less overall profit, and a worse reputation.
All the departments are now showing an internal profit — including customer relations. However, the company as a whole is now only just breaking even. How could that happen? There were a lot of grumbles about this, because each department felt constrained by that standardised system. In this scenario, once they are told to improve their internal profitability, the departments agree that they will each shift to the software platform that best suits their needs.
Product Support shift to Linux, Design shift to Macs, Customer Relations switch to an obscure platform that supports a highly efficient freeware expert system for handling complex legal questions, and so forth. Each of these changes is a great success; for instance, all the departments report that the new design documents are much easier to interpret, saving them significant amounts of work.
However, there is a new problem that arises. In the previous setup, all the departments could easily exchange documents etc. In the new setup, the situation is more complicated. For example, Design produces a brilliant mockup for a new product, but it can only be read by Macs with a particular piece of software installed. Some emails start being bounced back as undeliverable because of obscure interactions between the software systems that the different departments are using.
Who owns this problem? The different departments can all make a strong case for it not being their problem; they are all now more efficient and profitable, as a result of their new choice of IT platforms. It would make sense to have a new department just to handle the IT issues, where the black box is in the diagram.
A new department will mean new costs, which might well defeat the whole point of the internal profitability exercise.
So, in this example, improvements in all the subsystems have led to a worsening of the system as a whole. Lessons and applications So, what happens when someone spots this risk?
All too often, the scheme gets pushed ahead regardless, and ends badly for the system as a whole. There are plenty of high profile examples in politics and in business. The privatisation of the British rail system is a classic case. The knowledge of the boundaries of a given system is crucial in determining the nature of its interface with other systems for successful design. We can touch and feel them.
Physical System may be static or dynamic in nature. For example, desks and chairs are the physical parts of computer center which are static. A programmed computer is a dynamic system in which programs, data, and applications can change according to the user's needs.
Abstract systems are non-physical entities or conceptual that may be formulas, representation or model of a real system. Open or Closed Systems An open system must interact with its environment. It receives inputs from and delivers outputs to the outside of the system. For example, an information system which must adapt to the changing environmental conditions. A closed system does not interact with its environment. It is isolated from environmental influences. A completely closed system is rare in reality.
Adaptive and Non Adaptive System Adaptive System responds to the change in the environment in a way to improve their performance and to survive. For example, human beings, animals. Non Adaptive System is the system which does not respond to the environment. Permanent or Temporary System Permanent System persists for long time. For example, business policies.
Temporary System is made for specified time and after that they are demolished. For example, A DJ system is set up for a program and it is dissembled after the program.
Natural and Manufactured System Natural systems are created by the nature. For example, Solar system, seasonal system. Manufactured System is the man-made system.
For example, Rockets, dams, trains.
Systems and Subsystems
Deterministic or Probabilistic System Deterministic system operates in a predictable manner and the interaction between system components is known with certainty. For example, two molecules of hydrogen and one molecule of oxygen makes water.
Probabilistic System shows uncertain behavior. The exact output is not known. For example, Weather forecasting, mail delivery. For example, social clubs, societies. In Human-Machine System, both human and machines are involved to perform a particular task.
For example, Computer programming. Machine System is where human interference is neglected. All the tasks are performed by the machine. For example, an autonomous robot. This system includes hardware, software, communication, data, and application for producing information according to the need of an organization.
System Analysis and Design - Overview
For example, automatic library system, railway reservation system, banking system, etc. Systems Models A schematic model is a 2-D chart that shows system elements and their linkages. Different arrows are used to show information flow, material flow, and information feedback. Flow System Models A flow system model shows the orderly flow of the material, energy, and information that hold the system together. Static System Models They represent one pair of relationships such as activity—time or cost—quantity.Inventory Management System
The Gantt chart, for example, gives a static picture of an activity-time relationship. Dynamic System Models Business organizations are dynamic systems. A dynamic model approximates the type of organization or application that analysts deal with. It shows an ongoing, constantly changing status of the system. Categories of Information There are three categories of information related to managerial levels and the decision managers make. Strategic Information This information is required by topmost management for long range planning policies for next few years.