Question

Q2. Systems are Classified as either: Natural and Human-Made Systems, Physical and Conceptual Systems, Static and Dynamic Systems, Closed and Open Systems. Explain each of these four systems classes. Give examples.

Answer 1

I. Natural and Human- Made system

Natural System & Examples

The vast majority of systems are not made by people: they exist in nature and, by and large, serve their own purpose. Natural system are divided into two subcategories as

a. Physical systems

b. Living systems.

Physical systems include stellar systems: galaxies, solar systems, rivers, mountain ranges, rain etc.

Living systems includes all of the myriad animals and plants around us, as well as our own human race.

Human Made System & Examples

Human made systems are constructed, organized, and maintained by humans. These include such things as:

a. Social systems: organizations of laws, doctrines, customs, and so on.

b. Transportation systems: networks of highways, canals, airlines, ocean tankers, etc.

c. Communication systems: telephone, telex, smoke signals, etc.

d. Financial systems: accounting, inventory, general ledger, stock brokerage, and the like.

e. Computer, calendar, car etc.

II. Physical and Conceptual system

Physical System

Systems in the physical universe are composed of matter and energy, may embody information encoded in matter-energy carriers, and exhibit observable behavior. A physical system is an arrangement of parts or elements that together exhibit behavior that the individual constituents do not. The behavior of physical systems manifests itself as flows and exchanges of matter, energy and information, and interaction through force fields. The emergent property by which physical systems can be identified is that they perform processes to transform matter, energy and information in ways that their individual parts cannot.

Example of a Physical System is a pond, cat or wheel barrel. Every individual living thing, including a whole eco system, is a PS. There is a fine line between physical objects and systems. Generally, the more static an item seems to be, the more likely it is to be called an object. A baseball is generally considered an object, but at the molecular level is seen as a system. Conversely, a pond is generally considered a system, but if viewed macroscopically, as from a helicopter, it looks like an object.

Conceptual System

Conceptual systems are abstract systems of pure information, do not directly exhibit behavior, but exhibit meaning. Conceptual systems are composed of information or knowledge. Information in a conceptual system can be stored or transported in a physical system by being encoded into the matter or energy states of the physical system. A conceptual system is an arrangement of parts or elements that together exhibit meaning that the individual constituents do not. A conceptual system is a “knowledge structure” and is composed of information and knowledge elements. The elements of a conceptual system are related to each other but do not interact with each other. The conceptual system interacts with physical systems which create, modify and interpret it.

Example of a conceptual system is a simulation of a pond or the blue prints for a wheel barrel. Conceptual system provide means for communication and understanding. Math and science are the most fundamental conceptual system. Science is the conceptual system that is based on physical reality to the greatest extent possible. Because all scientific knowledge is attained by observation and experimentation, it is the most concrete conceptual system. Math on the other hand, is the most abstract. It can be applied to almost anything.

III. Static and Dynamic System

Static system

It is a system in which output at any instant of time depends on input sample at the same time.

Example: y(t) = 2 x(t)

For present value t=0, the system output is y(0) = 2x(0). Here, the output is only dependent upon present input. Hence the system is memory less or static.

Dynamic system

Definition: It is a system in which output at any instant of time depends on input sample at the same time as well as at other times.

Example: y(t) = 2 x(t) + 3 x(t-3)

For present value t=0, the system output is y(0) = 2x(0) + 3x(-3).

Here x(-3) is past value for the present input for which the system requires memory to get this output. Hence, the system is a dynamic system.

IV. Open and Closed System

Open System

Open system is a thermodynamic system where energy and matter can be exchanged with its surroundings. Open system can exchange matter with surroundings. The mass of the system will vary with time. Open system have boundaries which are not closed.

Example: Boiling food in an open pot.

Closed System

Closed system is a thermodynamic system where energy can be exchanged with its surroundings but not matter. Closed system cannot exchange matter with surroundings. The mass of the system is constant. In closed system the boundaries are completely closed.

Example:Boiling food in a pot and put a lid over the top is a closed system.