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1. Name the system your group will study this semester:
Home Air Condition System
Flow Diagram of AC System
2. A. Why it is an assemblage or combination of elements or parts?
Home AC system is an assemblage since it is made up of elements that interact
together to produce a particular effect such as motion, vibration, cooling etc. For
instance, the Air conditioner is made up of mechanical parts such as, compressor,
condenser, evaporator, compressor clutches, expansion devices etc. The elements
need to be related to function together and produce the desired result this means
that they have to identify each other. In addition, they need to be arranged in an
orderly manner this means that if in assemblage parts are disarranged they would
not communicate efficiently, and the system will not work. Each part is a subset of
each other, and if they do not have any relationship, the part is not an element of
the system.
2. B. Why the elements or parts are functionally related?
The parts or element of a system needs to be related to form a coherent group. This
is to make them work in harmony with each other. For instance, Air conditioner is a
mechanical system that uses the chemical to converts gas to liquid and vice versa. It
is make up of some parts that are functionally related. The compressor takes a
working fluid and compresses it, as the fluid gets compressed the molecules a forced
to be close to each other and as a result, increase the molecules energy and
temperature.
Now the working fluid leaves the compressor in the form of a gas and with a high
temperature, and get to the condenser. The condenser has metal fins that help to
lose the heat away and fins. By the time, the hot gas leaves the condenser it is
already converted back to liquid, with a very low temperature. Lastly, the cool liquid
gets into evaporator that evaporates the cooled liquid. As the liquid is evaporated, it
takes away the heat. In summary, for the cooling to take place compressor and
condenser should be related and have the same functioning power to avoiding
overloading each other.
2. C. Why the elements or parts form a unitary whole?
A system is said to be made up of element that form a unitary whole because it is
made up of several parts, which have difference functions but are joined to form a
complex unit that performs a specific function. If the one element likes a compressor
is not working, the whole system cannot operate too, even if condenser and other
parts are in good condition. In addition, when one element is absent again the
system cannot work that is one element cannot function.
2. A. Define the components:
Evaporators: An evaporator is a device which turns the liquid form of a chemical
into its gaseous form. The liquid is evaporated, or vaporized, into a gas.
Expansion Valve: is a component that controls the amount of refrigerant flow into
the evaporator thereby controlling the superheating at the outlet of the evaporator.
Compressors: circulates the refrigerant in the system under pressure, this
concentrates the heat it contains.
Receiver-Driers: Stores liquid refrigerant and which also holds a quantity of
desiccant condenser.
Condenser: is a component that removes heat from the system. Facilitates heat
transfer that is takes low pressure gas condenses into liquid and sends to receiver
drier.
Temperature Controls/Thermostat: Regulates the temperature and controls the
condenser to turn off/on.
3. B. Describe their attributes or measures of performance
Components Attributes
Evaporator
Heat Absorption, Phase transition (Liquid to Gas), Energy-dissipation
Evaporator
Blower Rotate, Blow Air (Cold), Pull Air (Hot),
Expansion
Valve Regulate Pressure, Open Valve, Close Valve
Compressor
Change Pressure (Low to High), Pass to Condenser,
Condenser
Transfer heat, Phase transition (Gas to Liquid), Blow Out (Hot air)
Receiver
Drier Absorb water, Filter Particles,
3. C. Relationships between pairs of linked components
1. Evaporator pumps cold refrigerant through evaporator coil.
2. Evaporator Blower Fan blows air over the coil, and the refrigerant in the coil
absorbs heat from the air.
3. Compressor receives the low pressured refrigerant gas and pressurizes it and
increase the temperature of the gas and sends it to the condenser.
4. The condenser receive the hot high pressure refrigerant gas and condenses back
into liquid by releases the heat and sends the liquid into the expansion valve.
5. Expansion Valve controls the amount of refrigerant and sends through the
evaporator.
Software quality can be evaluated from two perspectives. One, the external perspective,
consists of system or component attributes that are detectable by the user of the system or
component. The user does not need to be a systems analysis or software engineering
professional to recognize these attributes; no special training is required for their observation
and evaluation.
The internal perspective, on the other hand, consists of system or component attributes that
are detectable only upon access to the artifacts that make up the system or component; its
source code, documentation, process and product standards, data organization, and component
or system interrelationship specifications. These attributes are usually understood and
recognized by systems analysis and software engineering professionals, and require training in
them to make appropriate evaluations.
Software constructed must exhibit the following external software quality attributes (defined in
[IEEE610.12] unless otherwise noted):
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
accuracy
a qualitative assessment of freedom from error; a quantitative
measure of the magnitude of error, preferably expressed as a
function of the relative error;
flexibility
The ease with which a system or component can be modified for
use in applications or environments other than those for which it
was specifically designed. Synonym: adaptability;
compatibility The ability of two or more systems or components to perform their
required functions while sharing the same hardware or software
environment; the ability or two or more components to exchange
information [IEEE610.12]; the ease with which software products
may be combined with others [M88];
correctness the extent to which software is free from design and coding
defects; the extent to which software meets its requirements; the
extent to which software meets user expectations.
efficiency
the extent to which software performs its intended functions with a
minimum consumption of computing resources;
extendibility the ease with which a system or component can be modified to
increase its storage or functional capability [IEEE610.12]; the ease
with which software products may be adapted to changing
specifications [M88];
flexibility
the ease with which a system or component can be modified for
use in applications or environments other than those for which it
was specifically designed [IEEE610.12]; effort required to modify
an operational program [TB18-102];
integrity
the degree to which a system or component prevents unauthorized
access to, or modification of, computer programs or data
[IEEE610.12]; extent to which access to software or data by
unauthorized persons can be controlled [TB18-102];
interoperability effort required to couple one system with another [TB18-102];
maintainability the ease with which a software system or component can be
modified to correct faults, improve performance, or other attributes,
or adapt to a changed environment [IEEE610.12]; effort required to
locate and fix an error in an operational program [TB18-102];
John E. Boon, Jr.
(11)
portability
(12)
reliability
(13)
reusability
(14)
robustness
(15)
testability
(16)
usability
the ease with which software can be transferred from one
computer system or environment to another;
the ability of a system or component to perform a required function
under stated conditions for a specified period of time;
extent to which a program can be used in other applications -related to the packaging and scope of the functions that programs
perform [TB18-102];
the degree to which a system or component can function correctly
in the presence of invalid inputs or stressful environmental
conditions [IEEE610.12]; the extent to which software can continue
to operate correctly despite the introduction of invalid inputs or
abnormal conditions;
the degree to which a system or component facilitates the
establishment of test criteria and the performance of tests to
determine whether those criteria have been met; the degree to
which a requirement is stated in terms that permit establishment of
test criteria and performance of tests to determine whether those
criteria have been met [IEEE610.12]; effort required to test a
program to insure it performs its intended functions [TB18-102];
effort required to learn, operate, prepare input, and interpret output
of a program [TB18-102].
Software constructed must exhibit internal software quality attributes appropriate to the
software system or component. Function-oriented and object-oriented components must, at a
minimum, be evaluated on coupling and cohesion. Object-oriented components should also be
evaluated on inheritance hierarchy attributes and use of generics or templates. Software
components should be evaluated on information hiding and encapsulation; modules should
exhibit abstract data type attributes. Software components should be evaluated on internal error
detection and module-level exception handling attributes.
[IEEE610.12] STANDARDS COORDINATING COMMITTEE OF THE IEEE
COMPUTER SOCIETY, IEEE Standard Glossary of Software Engineering
Terminology, IEEE Std 610.12-1990, IEEE, New York, Corrected Edition 1991.
Reaffirmed 2002.
[TB18-102] TB 18-102, Technical Bulletin, Army Automation Quality Program,
Headquarters, Department of the Army, March 1984.
[M88] B. MEYER, Object-Oriented Software Construction, Prentice Hall, New York,
1988.
John E. Boon, Jr.