Training & Placements

Civil Engineering

1). How do you measure concrete?
Answer: Cubic feet, Cubic yards, Cubic Meter

2). Which is stronger solid steel rod or hollow steel pipe?
Answer: On a per pound basis, steel pipe is stronger in bending and is less likely to buckle in axial compression.

3). What is the tallest man made structure in the world?
Answer: The tallest man made structure is the KVLY-TV mast which is 2063 feet tall. The world’s tallest man made structure is Burj Dubai which is 800 meter tall.

4). What is braced excavation all about?
Answer: Excavations are braced to prevent the cave-in of surrounding unstable soil.

5). What is the meaning of soil reinforcement?
Answer: Soil reinforcement is the act of improving soil strength to enable it support or carry more load.
Two common examples are

6). What is aggregate?
Answer: Aggregate is the component of a composite material used to resist compressive stress.

7). What year was the keystone power plant in Indiana County constructed?
Answer: 1967 began commercial operation on unit 1.

8). What is the force exerted by the Tacoma narrows bridge?
Answer: The force exerted to the Tacoma narrows bridge was initially the wind resistance. The wind resistance caused the whole bridge to act as a system with forced vibration with damping

9). What are the uses of alloys in daily life and how are alloys made?
Answer: Alloying is not always done to produce a 'superior' material, but to produce materials having a desired requirement in the industry or elsewhere. A classic case is of lead solder (containing lead & tin), in which the melting point of the constituent elements are lowered, not necessarily a desirable property.
Alloying can be carried out using hot press method (a sheet of material is sandwiched with alloying material), rolling the heated base metal in a drum full of alloying metal powder, using hot spraying, galvanizing (dipping the base in a molten solution of alloying material) etc. Sometimes the alloying material is added in small proportions to the molten base metal (e.g., in production of different types of steel).

10). What is the world’s largest concrete dam?
Answer: The Grand Coulee Dam is said to be the largest concrete dam. Currently the world's largest concrete dam is the Itapúa Dam, an accomplishment of two neighboring countries, Brazil and Paraguay in South America.
Though it is not finished yet, the Three Gorges (or Sand pong) Dam on the Yangtze River in China will take over as the largest upon its completion, which is slated for 2009.

11). What are the main reasons of building collapse?
Answer: There are several reasons for building collapse. Passage of time is the main reason. Also, weak foundations, natural calamities like earthquakes, hurricanes, etc., are the major reasons for building collapse. Bombing and destruction is also another major reason.

12). State the applications of modulus of elasticity.
Answer: Modulus of elasticity is related to the flexibility of the material. The value of modulus of elasticity is pretty important in case of deflection of different materials used in building construction.

13). How are the freeway bridges built?
Answer: The traffic that is likely to go over the bridge at a time is estimated and the cement, rocked with rebar stanchions is placed over the freeway to build a bridge. Off-ramp from freeway to the bridge and on-ramp from the bridge to the freeway are constructed. Cement slabs are used to build a platform.

14). What is the basic difference in absorption, adsorption, and sorption?
Answer: Absorption refers to the phenomenon where an atom, molecule or ions enter any bulk phase like gas, solid or liquid. Absorption refers to the phenomenon where energy of photon is transferred to other entity.
13. Adsorption is similar to absorption. It refers to the surface rather than a volume. Adsorption takes place when the gas or liquid solute accumulates on the surface of solid. A substance diffuses in liquid or solid to form a solution.

15). Difference between routine maintenance and major maintenance for school facilities
Answer: Routine maintenance is handling the minor repairs of the school campus. Major maintenance can be total reconstruction or renovation of the school.

16). What is soil analysis?
Answer: Soil analysis is the testing of soil to determine the nutritional and elemental composition of soil. It is generally tested for knowing the contents of nitrogen, potassium and phosphorous.

17). State the building codes.
Answer: These codes are the set of specifications to ensure the safety associated with any building construction. These codes are associated with the height, spacing, and installation of the building. These codes play an important role in vacating the building in case of any emergency situations.
From these interview questions, you will get an idea of the questions interviewer can ask you in the civil engineering position interview. Refer to some more sample questions here and revise all the answers carefully.

18). What do you understand by “preset” during the installation process of bridge bearings?
Answer: During the installation of bridge bearings the size of the upper plates is reduced to save the material costs. This process is known as preset. Generally the upper bearing plate comprises of the following components:
* Length of bearing
* 2 x irreversible movement.
* 2 x reversible movement.
The bearing initially is placed right in the middle point of the upper bearing plate. No directional effects of irreversible movement are considered. But since the irreversible movement usually takes place in one direction only the displaced direction is placed away from the midpoint. In such cases the length of the upper plate is equal to the length of the length of the bearing + irreversible movement + 2 x reversible movement.

19). Why are steel plates inserted inside bearings in elastomeric bearings?
Answer: In order to make an elastomeric bearing act/ function as a soft spring it should be made to allow it to bulge laterally and also the stiffness compression can be increased by simply increasing the limiting amount of the lateral bulging. In many cases in order to increase the compression stiffness of the bearing the usage of metal plates is made. Once steel plates are included in the bearings the freedom of the bulge is restricted dramatically, also the deflection of the bearing is reduced as compared to a bearing without the presence of steel plates. The tensile stresses of the bearings are induced into the steel plates. But the presence of the metal plates does not affect the shear stiffness of the bearings.

20). In case if concrete box girder bridges how is the number of cells determined?
Answer: When the depth of a box girder bridge exceeds 1/6th or 1/5th of the bridge width then the design recommended is that of a single cell box girder bridge. But in case the depth of the bridge is lower than 1/6th of the bridge width then a twin-cell or in some cases multiple cell is the preferred choice. One should also note that even in the cases of wider bridges where there depths are comparatively low the number of cells should be minimized. This is so as there is noticeably not much improvement in the transverse load distribution when the number of cells of the box girder is higher than three or more.

21). Under what circumstances should pot bearings be used instead of elastomeric bearings?
Answer: Pot bearings are preferred over elastomeric bearings in situations where there are chances of high vertical loads in combinations of very large angle of rotations. Elastomeric bearings always require a large bearing surface so that a compression is maintained between the contact surfaces in between the piers and the bearings. This is not possible to maintain in high load and rotation environment. Also the usage of elastomeric bearings leads to the uneven distribution of stress on the piers. This results in some highly induced stresses to be targeted at the piers henceforth damaging them. Due to the above reasons pot bearings are preferred over elastomeric bearings in such cases.

22). Why should pumping be not used in case of concreting works?
Answer: During the pumping operation the pump exerted pressure must overcome any friction between the pumping pipes and the concrete, also the weight of the concrete and the pressure head when the concrete is placed above the pumps. Since only water is pump able, all the pressure generated is by the water that is present in the concrete. The major problem due to pumping is segregation effects and bleeding. In order to rectify and reduce these effects, generally the proportion of the cement is increased in order to increase the cohesion, which leads to the reduction of segregation and bleeding. Also if a proper selection of the aggregate grading can vastly improve the concrete pump ability.

23). Why should curing not be done by pending and polythene sheets?
Answer: The primary purpose of curing is to reduce the heat loss of concrete that is freshly placed to the atmosphere and in order to reduce the temperature gradient across the cross-section of the concrete. Pending is not preferred for curing as this method of thermal curing is greatly affected by cold winds. In addition to that in pending large amounts of water is used and has to be disposed off from the construction sites. Polythene sheets are used on the basis that it creates an airtight environment around the concrete surface henceforth reducing the chances of evaporation over fresh concrete surfaces. But the usage of polythene can be a drawback as it can be easily blown away by winds and also the water lost by self-desiccation cannot be replenished.

Computer Science & Engineering

C Interview Questions and Answers

 How can we construct an increment statement or decrement statement in C?
Answer: We can do this in two different ways. 1) By using the increment operator ++ and decrement operator. For example, the statement “i++” means to increment the value of x by 1. Likewise, the statement “x –” means to decrement the value of x by 1. 2) The 2nd way of writing increment statements is to use the conventional + plus sign or minus sign. In the case of “i++, another way to write it is “i = i +1.

List the different storage class specifiers in C?
Answer: static, auto, extern, register

Some Programmers debug their programs by placing comment symbols on some of the codes instead of deleting it. How does this aid in debugging?
Answer: Using comment symbols “/* */ ” in  a code, also called as commenting out, is a way of segregate some codes that you think maybe causing errors in the code, without deleting the program. The aim is that if the code is in fact correct, we can simply remove the comment symbols and continue on. It also saves you time and effort on having to retype the codes if you have deleted it in the first place.

What is call by value and call by reference in C Programming language?
We can pass value to function by two different ways: call by value and call by reference. In case of call by value, a copy of value is passed to the function, so original value is not modified in the call by value. But in case of call by reference, an address of value is passed to the function, so original value is modified in the call by reference.

How can we replace the following statement by using WHILE Loop?
For (x=1; x<=100; x++)
printf ("%d ", x *x );
Answer:
x=1;
while (x<=100)
{
printf ("%d ", x * x);
x++;
}

Name the different functions are used for dynamic memory allocation in C Program?
Answer: malloc (), calloc (), realloc (), free ()

Explain about spaghetti programming?
Answer: Spaghetti programming refers to programs that tend to get tangled and overlapped throughout the codes. This unorganized approach to coding is usually attributed to lack of experience on the part of the programmer. Spaghetti coding makes a program complex and analysing the codes difficult, and so must be avoided as much as possible.

Write the programming code to swap two numbers without using third variable?
Int x=10, y=20;
      printf("Before swap x=%d y=%d",x,y);
        y=x-y;   &nb
x=x-y;
printf(

In C program, how we can insert quote characters (‘ and ”) into the output screen?
Answer: This is a common problem for freshers/beginners because quotes are normally part of a “printf” statement in program. If we want to insert the quote character as part of the output, use the format specifiers , and ” (for double quote) , ’ (for single quote).

Differentiate between the = symbol and == symbol?
Answer: The = symbol is

For what purpose we use a ‘character?
<

What is modular programming?
An

Can the curly brackets { } be used to enclose a single line of code?
Answer: While curly brackets are mai

Check these operators and find out the incorrect operator and explain why? ( >=, <=, <>, ==)
Answer: The incorrect is <>. While this operator is correctly interpreted as “not equal to”” in writing conditional statements, it is not the proper operator to be used in C program. Instead, the operator! =  must be used to indicate “not equal to “condition.

What is ++X and X++ Operator?
Answer:

Can we use “int” data type to store the value 32768? Why?
Answer:No. “int” data type is capable of storing values from -32768 to 32767. To store 32768, you can use ““long int”” instead of “int”. You can also use ““unsigned int”, assuming you

Explain about the header files and what are the uses of header files in C program?
Answer:Header files are also called as library files. They contain 2 essential things: the definitions and prototypes of functions being used in a code. Simply put, commands that you use in C programming codes are actually functions that are defined from

Can we use two or more operators such as and be combined in a single line of program?
Answer:Yes, it’s perfectly valid to combine operators, especially if the need comes. For example: you can have a code like “printf (“Good ‘Morning ”) ” to output the text “Good”” on the first line and “Morning”” enclosed in single quotes to appear on the next two lines.

Why we are not declaring all the header files in every C p
Answer:The choice of declaring a header file at the top of C pr

List out the merits and demerits of array in C program?
Answer:
Merits:
(b) It is not nece
(c) Array elements are stored in continuous memory location.
Demerit:
(a) We cannot change size of array at the run time. So Wastage of memory space.
(b) Array can store only similar type of data.

When we will use the “Void” keyword  in a function?

Write a loop statement that will show the following output:for (b=1; b<=a; b++
printf("%s","*");
}printf(" ");

How can we generate random number
Answer: Random numbers are generated in C using the rand () command. For example: anyNum = rand() will generate any integer number beginning from 0, assuming that anyNum is a variable of type integer.

What is wrong in this statement?  scanf (%d, whatnumber);
Answer: This format is used f
Answer: You

Is it possible to initializ
Answer: Yes, you don’t have to write a separa
Answer: Reserved words are words that are part of the standard C language library. This

What is the different file extensions involved when coding in C?
Answer: Source codes in C are saved with .C file extension. Header files or library files have the .H file extension. Every time a program source code is successfully compiled, it creates an .OBJ object file, and

Explain about linked list?

Consider the below statement
Answer: FALSE. All reserved words must be written in lowercase; o

What are binary trees?
Answer: Binary trees are actually an extension of the concept of linked lists. A binary tree has two pointers, a left one and a right one. Each side can further branch to form additional nodes, which each node having two

Is this program statement is valid? INT = 10.
Answer: Assuming that INT is a variable of type float, this statement is valid. One may think that INT is a reserved word and must not be used for other purposes. However, recall that reserved words are express in lowercase, so the C compiler will not inte

What is wrong with this program statement? void = 10;
Answer: An

What is a newline escape sequence?
Answer: A newline escape sequence is representfore the actual output expression or after. 

Explain about output redirection?
Answer: It is the process of transferring data to an alternative output source other than the display screen. Output redirection allows a program to have its outp  

Write a simple code fragment that will check if a number i
Answer: If (num>=0)  

What is the difference between functions abs() and fabs()?<
Answer: These 2 fu  

What is the difference between functions abs() and fabs()?<

In C which function can be used to append a
Answer: The strcat function. It takes two parameters, the source string  

Do these two program statements perform the
Answer: Yes, they both do the exact same thing, which is to accept the next key pressed by t  

Differentiate between text files and binary files?

The % symbol has a special use in a printf statement. How can you place this character as
Answer: We can do this by using %% in the printf statement. For example, you can write pri  

Explain the advan
Answer: Storing data o  

What is calloc and malloc?

DBMS Interview Questions

What is database?
A database is a collection of information that is organized so that it can easily be accessed, managed, and updated.

What is DBMS?
DBMS stands for Database Management System. It is a collection of programs that enables user to create and maintain a database.

What is a Database system?
The database and DBMS software together is called as Database system.

What are the advantages of DBMS?

What is normalization?
It is a process of analysing the given relation schemas based on their Functional Dependencies (FDs) and primary key to achieve the properties

What is Data Model?
A collection of conceptual tools for describing data, data relationships data semantics and constraints.

What is E-R model?
This data model is based on real world that consists of basic objects  called entities and of relationship among these objects. Entities are described in a database by a set of attributes. 

What is Object Oriented model?
This model is based on collection of objects. An object contains values stored in instance variables with in the object. An object also contains bodies of code that operate on the object. These bodies of code are called methods. Objects that contain same types of values and the same methods are grouped together into classes. 

What is an Entity?
An entity is a thing or object of importance about which data must be captured. 

What is DDL (Data Definition Language)?
A data base schema is specifies by a set of definitions expressed by a special language called DDL. 

What is DML (Data Manipulation Language)?
This language that enable user to access or manipulate data as organised  by appropriate data model. Procedural DML or Low level: DML requires a user to specify what data are needed and how to get those data. Non-Procedural DML or High level: DML requires a user to specify what data are needed without specifying how  to get those data 

What is DML Compiler?
It translates DML statements in a query language into low-level instruction that the query evaluation engine can understand. 

What is Query evaluation engine?
It executes low-level instruction generated by compiler. 

What is Functional Dependency?
Functional Dependency is the starting point of normalization. Functional Dependency exists when a relation between two attributes allows you to uniquely determine the corresponding attribute’s value. 

What is 1 NF (Normal Form)?
The first normal form or 1NF is the first and the simplest type of normalization that can be implemented in a database. The main aims of 1NF are to: 
Eliminate duplicative columns from the same table.
Create separate tables for each group of related data and identify each row with a unique column (the primary key).

What is Fully Functional dependency?
A functional dependency X Y is fully functional dependency if removal of any attribute A from X means that the dependency does not hold any more. 

What is 2NF?
A relation schema R is in 2NF if it is in 1NF and every non-prime attribute A in R is fully functionally dependent on primary key. 

What is 3NF?
A relation is in third normal form if it is in Second Normal Form and there are no functional (transitive) dependencies between two (or more) non-primary key attributes. 

What is BCNF (Boyce-Codd Normal Form)?
A table is in Boyce-Codd normal form (BCNF) if and only if it is in 3NF and every determinant is a candidate key. 

What is 4NF?
Fourth normal form requires that a table be BCNF and contain no multi-valued dependencies. 

What is 5NF?
A table is in fifth normal form (5NF) or Project-Join Normal Form (PJNF) if it is in 4NF and it cannot have a lossless decomposition into any number of smaller tables. 

What is a query?
A query with respect to DBMS relates to user commands that are used to interact with a data base. 

What is meant by query optimization?
The phase that identifies an efficient execution plan for evaluating a query that has the least estimated cost is referred to as query optimization. 

What is an attribute?
It is a particular property, which describes the entity. 

What is RDBMS?
Relational Data Base Management Systems (RDBMS) are database management systems that maintain data records and indices in tables. 

What’s difference between DBMS and RDBMS?
DBMS provides a systematic and organized way of storing, managing and retrieving from collection of logically related information. RDBMS also provides what DBMS provides but above that it provides relationship integrity. 

What is SQL?
DSQL stands for Structured Query Language. SQL is an ANSI (American National Standards Institute) standard computer language for accessing and manipulating database systems. SQL statements are used to retrieve and update data in a database.

What is Stored Procedure?
A stored procedure is a named group of SQL statements that have been previously created and stored in the server database.

What is a view?
A view may be a subset of the database or it may contain virtual data that is derived from the database files but is not explicitly stored.

What is Trigger?
A trigger is a SQL procedure that initiates an action when an event (INSERT, DELETE or UPDATE) occurs.

What is Index?
An index is a physical structure containing pointers to the data.

What is extension and intension?
Extension -It is the number of tuples present in a table at any instance. This is time dependent.Intension -It is a constant value that gives the name, structure of table and the constraints laid on it.

What do you mean by atomicity and aggregation?
Atomicity-Atomicity states that database modifications must follow an “all or nothing” rule. Each transaction is said to be “atomic.” If one part   of the transaction fails, the entire transaction fails. Aggregation - A feature of the entity relationship model that allows a relationship set to participate in another relationship set. This is indicated on an ER diagram by drawing a dashed box around the aggregation.

What is RDBMS KERNEL?
Two important pieces of RDBMS architecture are the kernel, which is the software, and the data dictionary, which consists of the system- level data structures used by the kernel to manage the database.

Name the sub-systems of a RDBMS?
I/O, Security, Language Processing, Process Control, Storage Management, Logging and Recovery, Distribution Control, Transaction Control, Memory Management, Lock Management.

How do you communicate with an RDBMS?
You communicate with an RDBMS using Structured Query Language (SQL)

Disadvantage in File Processing System?

What is VDL (View Definition Language)?
It specifies user views and their mappings to the conceptual schema.

What is SDL (Storage Definition Language)?
This language is to specify the internal schema. This language may Specify the mapping between two schemas.

Describe concurrency control?
Concurrency control is the process managing simultaneous operations against a database so that database integrity is no compromised. There are two approaches to concurrency control.The pessimistic approach involves locking and the optimistic approach involves versioning.

Describe the difference between homogeneous and heterogeneous distributed database?
A homogenous database is one that uses the same DBMS at each node. A heterogeneous database is one that may have a different DBMS at each node.

What is a distributed database?
A distributed database is a single logical database that is spread across more than one node or locations that are all connected via some communication link.

Explain the difference between two and three-tier architectures?
Three-tier architecture includes a client and two server layers.The   application code is stored on the application server and the database   is stored on the database server. A two-tier architecture includes a client and one server layer. The database is stored on the database server.

Briefly describe the three types of SQL commands?
Data definition language commands are used to create, alter, and drop tables. Data manipulation commands are used to insert, modify, update, and query data in the database. Data control language commands help the DBA to control the database.

List some of the properties of a relation?
Relations in a database have a unique name and no multi valued attributes exist. Each row is unique and each attribute within a relation has a unique name. The sequence of both columns and rows is irrelevant.

Explain the differences between an intranet and an extranet?
An Internet database is accessible by everyone who has access to a Web site. An intranet database limits access to only people within a given organization.

What is SQL Deadlock?
Deadlock is a unique situation in a multi user system that causes two or more users to wait indefinitely for a locked resource.

What is a Catalog?
A catalog is a table that contains the information such as structure of each file, the type and storage format of each data item and various constraints on the data .The information stored in the catalog is called Metadata.

What is data ware housing & OLAP?
Data warehousing and OLAP (online analytical processing) systems are the techniques used in many companies to extract and analyze useful  information from very large databases for decision making .

Describe the three levels of data abstraction?
Physical level: The lowest level of abstraction describes how data are stored.
Logical level: The next higher level of abstraction, describes what data are stored in database and what relationship among those data.
View level: The highest level of abstraction describes only part of entire database.

What is Data Independence?
Data independence means that the application is independent of the storage structure and access strategy of data.

How many types of relationship exist in database designing?

What is order by clause?
ORDER BY clause helps to sort the data in either ascending order to descending

What is the use of DBCC commands?
DBCC stands for database consistency checker. We use these commands to check   the consistency of the databases, i.e., maintenance, validation task and status checks.

What is Collation?
Collation refers to a set of rules that determine how data is sorted and compared.

What is difference between DELETE & TRUNCATE commands?
Delete command removes the rows from a table based on the condition that we provide with a WHERE clause. Truncate will actually remove all the rows from a table and there will be no data in the table after we run the truncate command.

What is Hashing technique?
This is a primary file organization technique that provides very fast access to records on certain search conditions.

What is a transaction?
A transaction is a logical unit of database processing that includes one or more database access operations.

What are the different phases of Transaction?

What is “transparent dbms”?
It is one, which keeps its physical structure hidden from user.

What are the primitive operations common to all record management System?
Addition, deletion and modification.

Explain the differences between structured data and unstructured data.
Structured data are facts concerning objects and events. The most important structured data are numeric, character, and dates.
Structured data are stored in tabular form. Unstructured data are multimedia data such as documents, photographs, maps, images, sound, and video clips. Unstructured data are most commonly found on Web servers and Web-enabled databases.

What are the major functions of the database administrator?
Managing database structure, controlling concurrent processing, managing processing rights and responsibilities, developing database security, providing for database recovery, managing the DBMS and maintaining the data repository.

What is a dependency graph?
A dependency graph is a diagram that is used to portray the connections between database elements.

Explain the difference between an exclusive lock and a shared lock?
An exclusive lock prohibits other users from reading the locked resource; a shared lock allows other users to read the locked resource, but they cannot update it.

Explain the "paradigm mismatch" between SQL and application programming language
SQL statements return a set of rows, while an application program works on one row at a time. To resolve this mismatch the results of  SQL statements are processed as pseudo files, using a cursor or pointer to specify which row is being processed.

Name four applications for triggers.

What are the advantages of using stored procedures?
The advantages of stored procedures are

Explain the difference between attributes and identifiers
Entities have attributes. Attributes are properties that describe the entity's characteristics. Entity instances have identifiers. Identifiers are attributes that name, or identify, entity instances.

What is Enterprise Resource Planning (ERP), and what kind of a database is used in an ERP application?
Enterprise Resource Planning (ERP) is an information system used in manufacturing companies and includes sales, inventory, production planning, purchasing and other business functions. An ERP system typically uses a multiuser database.

Describe the difference between embedded and dynamic SQL?
Embedded SQL is the process of including hard coded SQL statements. These statements do not change unless the source code is modified. Dynamic SQL is the process of generating SQL on the fly.The statements generated does not have to be the same each time.

Explain a join between tables
A join allows tables to be linked to other tables when a relationship between the tables exists. The relationships are established by using a common column in the tables and often use the primary/foreign key relationship.

Describe a subquery.
A subquery is a query that is composed of two queries. The first query (inner query) is within the WHERE clause of the other query  (outer query).

Compare a hierarchical and network database model?
The hierarchical model is a top-down structure where each parent may have many children but each child can have only one parent. This model supports one-to-one and one-to-many relationships. The network model can be much more flexible than the hierarchical model since each parent can have multiple children but each child can also have multiple parents. This model supports one-to-one, one-to-many, and many-to-many relationships.

Explain the difference between a dynamic and materialized view.
A dynamic view may be created every time that a specific view is requested by a user. A materialized view is created and or updated infrequently and it must be synchronized with its associated base table(s).

Explain what needs to happen to convert a relation to third normal form.
First you must verify that a relation is in both first normal form and second normal form. If the relation is not, you must convert into second normal form. After a relation is in second normal form, you must remove all transitive dependencies.

Describe the four types of indexes?
A unique primary index is unique and is used to find and store a row. A nonunique primary index is not unique and is used to find a row but also where to store a row (based on its unique primary index). A unique secondary index is unique for each row and used to find table rows. A nonunique secondary index is not unique and used to find table rows.

Describe the four types of indexes?
Minimum cardinality is the minimum number of instances of an entity that can be associated with each instance of another entity.  Maximum cardinality is the maximum number of instances of an entity that can be associated with each instance of another entity.

What is deadlock? How can it be avoided? How can it be resolved once it occurs?
Deadlock occurs when two transactions are each waiting on a resource that the other transaction holds. Deadlock can be prevented by requiring transactions to acquire all locks at the same time; once it occurs, the only way to cure it is to abort one of the transactions and back out of partially completed work.

Explain what we mean by an ACID transaction.
An ACID transaction is one that is atomic, consistent, isolated, and durable. Durable means that database changes are permanent. Consistency can mean either statement level or transaction level consistency. With transaction level consistency, a transaction may not see its own changes.Atomic means it is performed as a unit.

Under what conditions should indexes be used?
Indexes can be created to enforce uniqueness, to facilitate sorting, and to enable fast retrieval by column values. A good candidate for an index is a column that is frequently used with equal conditions in WHERE clauses.

What is difference between SQL and SQL SERVER?
SQL is a language that provides an interface to RDBMS, developed by IBM. SQL SERVER is a RDBMS just like Oracle, DB2.

What is Specialization?
It is the process of defining a set of subclasses of an entity type where each subclass contain all the attributes and relationships of the parent entity and may have additional attributes and relationships which are specific to itself.

What is generalization?
It is the process of finding common attributes and relations of a number of entities and defining a common super class for them.

What is meant by Proactive, Retroactive and Simultaneous Update?
Proactive Update: The updates that are applied to database before it becomes effective in real world.
Retroactive Update: The updates that are applied to database before it becomes effective in real world.
Simultaneous Update: The updates that are applied to database at the same time when it becomes effective in real world.

What is RAID Technology?
Redundant array of inexpensive (or independent) disks. The main goal of raid technology is to even out the widely different rates of performance improvement of disks against those in memory and microprocessor. Raid technology employs the technique of data striping to achieve higher transfer rates. 

What are serial, non serial schedule?
A schedule S is serial if, for every transaction T participating in the schedule, all the operations of T is executed consecutively in the schedule, otherwise, the schedule is called non-serial schedule.

What are conflict serializable schedules?
A schedule S of n transactions is serializable if it is equivalent to some serial schedule of the same n transactions.

What is view serializable?
A schedule is said to be view serializable if it is view equivalent with some serial schedule.

What is a foreign key?
A key of a relation schema is called as a foreign key if it is the primary key of some other relation to which it is related to.

What are the disadvantages of using a dbms?

What is Lossless join property?
It guarantees that the spurious tuple generation does not occur with respect to relation schemas after decomposition.

What is a Phantom Deadlock?
In distributed deadlock detection, the delay in propagating local information might cause the deadlock detection algorithms to identify deadlocks that do not really exist. Such situations are called phantom deadlocks and they lead to unnecessary aborts.

What is a checkpoint and When does it occur?
A Checkpoint is like a snapshot of the DBMS state. By taking checkpoints, the DBMS can reduce the amount of work to be done during restart in the event of subsequent crashes.

What is schema?
The description of a data base is called the database schema , which is specified during database design and is not expected to change frequently . A displayed schema is called schema diagram .We call each object in the schema as schema construct.

Electronics & Communication Engineering

What are different categories of antenna and give an example of each?

Different categories of antenna are as follows:

What is handover and what are its types?
Handover in mobile communication refers to the process of transferring a call from one network cell to another without breaking the call.
There are two types of handover which are as follows:

What is ionosphere bending?
When a radio wave travels into the ionosphere layer it experiences refraction due to difference in density. The density of ionospheric layer is rarer than the layer below which causes the radio wave to be bent away from the normal. Also the radio wave experiences a force from the ions in the ionospheric layer. If incident at the correct angle the radio wave is completely reflected back to the inner atmosphere due to total internal reflection. This phenomenon is called ionospheric reflection and is used in mobile communication for radio wave propagation also known as ionospheric bending of radio waves.

What is CDMA?
CDMA stands for Code Division Multiple Access which uses digital format. In CDMA systems several transmissions via the radio interface take place simultaneously on the same frequency bandwidth. User data is combined at the transmitter’s side with a code, then transmitted. On air, all transmission get mixed. At the receiver's side the same code is used as in the transmitter’s side. The code helps the receiver to filter the user information of the transmitter from incoming mixture of all transmissions on the same frequency band and same time.

Explain the concept of frequency re-use.
The whole of the geographical area is divided into hexagonal shape geometrical area called cell and each cell having its own transceiver. Each BTS (cell site) allocated different band of frequency or different channel. Each BTS antenna is designed in such a way that i cover cell area in which it is placed with frequency allotted without interfering other cell signals. The design process of selecting and allocating channel groups for all of the cellular base station within system is called frequency reuse.

Explain Bluetooth.
Bluetooth is designed to be a personal area network, where participating entities are mobile and require sporadic communication with others. It is omni directional i.e. it does not have line of sight limitation like infra red does. Ericsson started the work on Bluetooth and named it after the Danish king Harold Bluetooth. Bluetooth operates in the 2.4 GHz area of spectrum and provides a range of 10 metres. It offers transfer speeds of around 720 Kbps.

What are GPRS services?
GPRS services are defined to fall in one of the two categories:
- PTP ( Point to point)
- PTM ( Point to Multipoint)
Some of the GPRS services are not likely to be provided by network operators during early deployment of GPRS due in part to the phased development of standard. Market demand is another factor affecting the decision of operators regarding which services to offer first.

What are the advantages of CDMA?
Advantages of CDMa are as follows:

What are the advantages of spread spectrum?
Spread spectrum has the following advantages:

Explain the steps involved in demodulating a signal.
Once the signal is coded, modulated and then sent, the receiver must demodulate the signal. This is usually done in two steps:

How can a Pseudo Random Noise Code be usable?
To be usable for direct sequence spreading, a PN code must meet the following conditions: