Software Engineering -1
Question No: 1
Define Asynchronous Messages and Synchronous Messages.
Answer:
Asynchronous Messages:
Asynchronous messages are “signals,” denoted by a half arrow. They do not block the caller. Asynchronous
messages typically perform the following actions:
1 Create a new thread
2 Create a new object
Communicate with a thread that is already running
Synchronous Messages:
Synchronous messages are “call events” and are denoted by the full arrow. They represent nested flow of
control which is typically implemented as an operation call. In case of a synchronous message, the caller waits
for the called routine to complete its operation before moving forward.
Question No: 2
Law of balancing act in software
Answer:
The Balancing Act!
Software Engineering is actually the balancing act. You have to balance many things like cost, user
friendliness, Efficiency, Reliability etc. You have to analyze which one is the more important feature for your
software is it reliability, efficiency, user friendliness or something else. There is always a trade-off among all
these requirements of software. It may be the case that if you try to make it more user-friendly then the
efficiency may suffer. And if you try to make it more cost-effective then reliability may suffer. Therefore there
is always a trade-off between these characteristics of software. These requirements may be conflicting. For
example, there may be tension among the
following:
1 Cost vs. Efficiency
2 Cost vs. Reliability
3 Efficiency vs. User-interface
A Software engineer is required to analyze these conflicting entities and tries to strike a balance.
Question No: 3
HOW DO YOU DETERMINE THAT AN OBJECTIVE BELONGS TO CERTAIN CLASS?
Answer:
The basic unit of object oriented design is an object. An object can be defined as a tangible entity that exhibits
some well defined behavior. The structure and behavior of similar objects are defined in their common class. A
class specifies an interface and defines an implementation.
Question No: 4
What is meant by “System’s Static View"?
Answer:
Static view of semantic classes.
Requirements are assessed and classes are extracted (and represented) as part of the analysis model.
Static view of attributes.
Every class must be explicitly described. The attributes associated with the class
provide a description of the class.
Static view of relationships.
Objects are “connected” to one another in a variety of ways. The analysis model must represent these.
Static view of behaviors.
The relationships just noted define a set of behaviors that accommodate the usage scenario (use-cases) of the
system
Question No: 5
What is behavior driven perceptive of an objective?
Answer:
Behavior is how an object acts and reacts in terms of its state changes and message passing. The behavior of an
object is completely defined by its actions. A message is some action that one object performs upon another in
order to elicit a reaction. The operations that clients may perform upon an object are called methods.
Question No: 6
What is Textual Analysis? Explain it
Answer:
Textual analysis was developed by Abbot and then extended by Graham and others. In this technique different
parts of speech are identified within the text of the specification and these parts are modeled using different
components.
Question No: 7
What is Software Architecture?
Answer:
Architecture is the organizational structure of a system. Architecture can be recursively decomposed into parts
that interact through interfaces, relationships that connect parts, and constraints for assembling parts. Parts that
interact through interfaces include classes, components and subsystems.
Question No: 8
What is the Cardinality of Objective?
Answer :
Cardinality. The data model must be capable of representing the number of occurrences Objects in a given
relationship. Tillmann [TIL93] defines the cardinality of an object/relationship pair in the following manner:
1) One-to-one (l:l)—An occurrence of [object] 'A' can relate to one and only one occurrence of [object]
'B,' and an occurrence of 'B' can relate to only one occurrence of 'A.'
2) One-to-many (l:N)—One occurrence of [object] 'A' can relate to one or many occurrences of [object]
'B,' but an occurrence of 'B' can relate to only one occurrence of 'A.' For example, a mother can have
many children, but a child can have only one mother.
3) Many-to-many (M:N)—An occurrence of [object] 'A' can relate to one or more occurrences of 'B,'
while an occurrence of 'B' can relate to one or more occurrences of 'A.' For example, an uncle can have
many nephews, while a nephew can have many uncles.
Question No: 9
Define abstraction?
Answer:
An abstraction is a technique in which we construct a model of an entity based upon its essential characteristics
and ignore the inessential details.
Question No: 10
Is the design of software architecture a creative process?
Answer:
Design of software architecture is a creative and iterative process. This involves performing a number of
activities, not necessarily in any particular order or sequence.
Question No: 11
Suppose you are working as a software engineer involved in the development of an e-commerce website.
What are the 2 most important characteristics your software must have?
Answer:
Two most important characteristics are that software should be reliable and useable.
Question No: 12
What is the purpose of collaboration diagrams?
Answer:
Collaboration diagrams can also be used to depict the dynamic behavior of a system. They show how objects
interact with respect to organizational units (boundaries!). Collaboration diagrams can also show synchronous,
asynchronous, create, and destroy message using the same notation as used in sequence diagrams.
Question No: 13
What is the difference between Aggregation and Association?
Answer:
As compared to association, aggregation implies a tighter coupling between the two objects which are involved
in this relationship. Therefore, one way to differentiate between aggregation and association is that if the two
objects are tightly coupled, that is, if they cannot exist independently, it is an aggregation, and if they are
usually considered as independent, it is an association.
Question No: 14
what parameters are used to measure and analyze design quality?
Answer:
A software design can be looked at from different angles and different parameters can be used to measure and
analyze its quality. These parameters include efficiency, compactness, reusability, and maintainability. A good
design from one angle may not seem to be suitable when looked from a different perspective. For example, a
design that yields efficient and compact code may not be very easy to maintain. In order to establish whether a
particular design is good or not, we therefore have to look at the project and application requirements.
Question No: 15
Discuss some of the purpose of interacting diagram?
Answer:
The purposes of interaction diagrams are to visualize the interactive behaviour of the system. Now visualizing
interaction is a difficult task. So the solution is to use different types of models to capture the different aspects
of the interaction.
That is why sequence and collaboration diagrams are used to capture dynamic nature but from a different angle.
So the purposes of interaction diagram can be describes as:
1 To capture dynamic behaviour of a system.
2 To describe the message flow in the system.
3 To describe structural organization of the objects.
4 To describe interaction among objects.
Question No: 16
What should be consideration for maintain design?
Answer:
In order to make a design that is maintainable, it should be understandable and the changes should be local in
effect. That is, it should be such that a change in some part of the system should not affect other parts of the
system. This is achieved by applying the principles of modularity, abstraction, and separation of concern. If
applied properly, these principles yield a design that is said to be more cohesive and loosely coupled and thus is
easy to maintain.
Question No: 18
It is fact that good design makes maintenance easier. Which design principle help this to be achieved?
Answer:
A good design from one angle may not seem to be suitable when looked from a different perspective. For
example, a design that
yields efficient and compact code may not be very easy to maintain. In order to establish whether a particular
design is good or not, we therefore have to look at the project and application requirements.
Question No: 19
To manage the complexity of the system we need to apply the principle of abstraction. Discuss briefly?
Answer:
An abstraction is a technique in which we construct a model of an entity based upon its essential characteristics
and ignore the inessential details. The principle of abstraction also helps us in handling the inherent complexity
of a system by allowing us to look at its important external characteristic, at the same time, hiding its inner
complexity. Hiding the internal details is called encapsulation.
Question No: 20
Differentiate between architectural design and system architecture in a single line?
Answer:
Architecture faces towards strategy, structure and purpose, towards the abstract while Design faces towards
implementation and practice, towards the concrete.
Question No: 21
What are architectural designs Process, explain briefly?
Answer:
System structuring:
System structuring is concerned with decomposing the system into interacting sub-systems. The system is
decomposed into several principal sub-systems and communications between these sub-systems are identified.
Control modeling:
Control modeling establishes a model of the control relationships between the different parts of the system.
Modular decomposition:
During this activity, the identified sub-systems are decomposed into modules. This design process is further
elaborated in the following section where architectural views are discussed.
Question No: 22
Discuss the relationship between sequence diagram and logical complexity?
Answer:
It is important to understand that the diagrams are meant to make things clear. Therefore, in order to keep them
simple, special attentions should be paid to the conditional logic. If it is simple then there is no harm in adding
it to the diagram. On the other hand if the logic is complex then we should draw separate diagrams like flow
charts.
Question No: 23
Define Motivation of GUI
Answer:
Motivation for GUI
1 System users often judge a system by its interface rather than its functionality
2 A poorly designed interface can cause a user to make catastrophic errors
3 Poor user interface design is the reason why so many software systems are never used
Question No: 24
Keeping in mind the Connie's case study, what rule of thumbs was identified, list them down.
Answer:
Who I Know - Rules of Thumb
1 an actor knows about its participants person knows about cashier
2 a transaction knows about its participants a session knows about its register and cashier
3 A transaction contains its transaction line items sale contains its sales line items
4 A transaction knows its sub transactions session knows about its sales sale knows about its payments
5 A place knows about its transactions store knows about its sessions
6 A place knows about its descriptive objects store knows about its tax categories
7 A container knows about its contents a store knows about its cashiers, items, and registers
Question No: 25
The CPU of a computer consists of an ALU and a CU. Intel and AMD are two types of CPUs, which are
widely used in computers. Users of computers can be either novices or experts.
Consider the following classes.
(i) CPU and AMD
(ii) User and Computer
(iii) CPU and ALU
Answer:
CPU and AMD:
There is relationship between CPU and AMD is “A kind of” type as AMD is a kind of CPU.
User and Computer:
The relationship between User and Computer is “simple Association” type as there is weak relationship
between user and computer.
CPU and ALU:
Relationship between CPU and ALU is “composition” type as ALU is a part of CPU.
Question No: 26
What is action-oriented approach for Software Design?
Answer:
In the case of action-oriented approach, data is decomposed according to functionality requirements. That is,
decomposition revolves around function. In the OO approach, decomposition of a problem revolves around
data. Action-oriented paradigm focuses only on the functionality of a system and typically ignores the data until
it is required. Object- oriented paradigm focuses both on the functionality and the data at the same time. The
basic difference between these two is decentralized control mechanism versus centralized control mechanism
respectively. Decentralization gives OO the ability to handle essential complexity better than action-oriented
approach.
Question No: 27
Collaboration Diagrams depict Dynamic behavior of the system, explain it.
Answer:
Collaboration diagrams:
Collaboration diagrams can also be used to depict the dynamic behavior of a system. They show how objects
interact with respect to organizational units (boundaries!).
Since a boundary shapes communication between system and outside world e.g. user interface or other system,
collaboration diagrams can be used to show this aspect of the system. The sequence of messages determined by
numbering such as 1, 2, 3, 4, This shows which operation calls which other operation.
Question No: 28
To manage the complexity of the system we need to apply the principles of separation of concern. Discuss
briefly
Answer:
Separation of concern allows us to deal with different individual aspects of a problem by considering these
aspects in isolation and independent of each other. A complex system may be divided into smaller pieces of
lesser complexity called modules.
Question No: 29
What is elaborated Use case? Explain it
Answer:
After the derivation of the use case model, each use is elaborated by adding detail of interaction between the
user and the software system. An elaborated use case has the following components:
Use Case Name, actors, summary, precondition, post-condition, extend, uses, normal course of events,
alternative path, exception, assumption.
Question No: 30
How can we decrease Coupling explain it.
Answer:
That is, we can reduce the coupling of a system by minimizing the number of messages in the protocol of a
class.
Question No: 31
Narrate some of the architectural design guidelines that can help in addressing non-functional
requirements challenges.
Answer:
Software architecture must address the non-functional as well as the functional requirements of the software
system. Following are some of the architectural design.
Performance –Performance can be enhanced by localizing operations to minimize sub-system communication.
That is, try to have self-contained modules as much as possible so that inter-module communication is
minimized.
Security –Security can be improved by using a layered architecture with critical assets put in inner layers.
Safety –Safety-critical components should be isolated
Availability –Availability can be ensured by building redundancy in the system and having redundant
components in the architecture.
Maintainability–Maintainability is directly related with simplicity. Therefore, maintainability can be increased
by using fine-grain, self-contained components.
Question No: 32
What is the importance of Classification in identifying Classes and objects?
Answer:
Consider a large university library. Tens of thousands of books, periodicals, and other information resources are
available for use. But to access these resources, a categorization scheme must be developed. To navigate this
large volume of information, librarians have defined a classification scheme that includes a Library of Congress
classification code, keywords, author names, and other index entries. All enable the user to find the needed
resource quickly and easily.
Question No: 33
What is the difference between Association and composition?
Answer:
In Association, interacting objects have no intrinsic relationship with other object. It is the weakest link
between objects. While in Composition An object may be composed of other smaller objects, the relationship
between the “part” objects and the “whole”.
Question No: 34
How the objects are identified in peter codd’s technique?
Answer:
Objects are identifying in the following way.
Select actors
Actors are people and organizations that take part in the system under consideration.Examples of actors are:
person, organization (agency, company, corporation, foundation).
Select Participants
A participant is a role that each actor plays in the system under consideration. Examples of participants are:
agent, applicant, buyer, cashier, clerk, customer, dealer, and distributor. Etc.
Select Places
Places are where things come to rest or places that contain other objects. Examples of places are: airport,
assembly-line, bank, city, clinic, country, depot, garage and hospital etc.
Select Transactions
Transactions are the “events”. These transactions usually come from a window (GUI), some object which
monitors for significant event and logs that information, or a another system that interacts with the system
under consideration and logs some information. Examples of transactions are: agreement, assignment,
authorization, contract, delivery, deposit, incident, inquiry, order, payment, problem report, purchase and sales
etc.
Select Container Objects
Containers are objects that hold other objects. e.g. bin, box, cabinet, folder, locker, safe, shelf, etc. Therefore a
place is also a container but every container need not be a place.
Select Tangible things
Take a “walk” through the system and select “tangible” things around you used in the problem domain. These
may be characterized as all the remaining (not yet selected) “nouns” that make up the problem domain.
Examples are: account, book, calendar, cash box, cash drawer, item, plan, procedure, product, schedule, skill,
tool, etc
Question No: 35
Define cohesion.
Answer:
Cohesion is an internal property of a module. Cohesion describes the intra-component linkages while couple
shows the inter-component linkages. Cohesion measures the independence of a module.
Diya ko 
[DOUBLEPOST=1363027261][/DOUBLEPOST]@
Thankss!