Bachelor of Technology or Bachelor of Engineering

The All India Council for Technical Education is a statutory body, and a national-level council for technical education, under the Department of Higher Education

All India Council For Technical Education (AICTE), New Delhi

Identification of expansive soil Foundation on Expansive Soils-Geotechnical Engineering (BE/BTech - CIVIL)

Geotechnical Engineering

BE/BTech

Nature Of Environment Intelligent Agents -Artificial Intelligence

Best First Search (Informed Search)
1. Best first search is a traversal technique that decides which node is to be visited next by checking
which node is the most promising one and then check it. For this it uses an evaluation function to
decide the traversal.
2. The best first search belongs to a branch of search algorithms known as heuristic search algorithms.
The basic idea of heuristic search is that, rather than trying all possible search paths at each step, we
try to find which paths seem to be getting us nearer to our goal state
3. In the two basic search algorithms we have studied before i.e., depth first search and breadth first
search we proceed in a systematic way by discovering/finding/exploring nodes in a predetermined
order. In these algorithms at each step during the process of searching there is no assessment of
which way to go because the method of moving is fixed at the outset
4. This best first search technique of tree traversal comes under the category of heuristic search or
informed search technique.



5. The cost of nodes is stored in a priority queue. This makes implementation of best-first search is
same as that of breadth First search. We will use the priority queue just like we use a queue for
BFS.
6. Best First Search combines the benefits of both depth first and breadth first search by moving along
a single path at a time but change paths whenever some other path looks more promising than the
current path.
Let assume two different list of nodes: is the list of nodes which have been found but yet not expanded
i.e., the
 OPEN list  nodes which have been discovered /generated but whose children/successors are yet not
discovered. Open list can be implemented in the form of a queue in which the nodes will be arranged in
the order of decreasing prioity from the front i.e., the node with the most promising heuristic value (i.e.,
the highest priority node) will be at the first place in the list.. contains expanded/visited nodes i.e., th
anodes whose successors are
 CLOSED list  also genereated. We require to kep the nodes in memory I we want to search a graph
rather than a tree, since whenever a new node is generated we need to check if it has been generated
before.



Algorithm: Best First Search
1Place the start node on the OPEN list.
2. Create a list called CLOSED i.e., initially empty.
3. If the OPEN list is empty search ends unsuccessfully.
4. Remove the first node on OPEN list and put this node on CLOSED list.
5. If this is a goal node, search ends successfully.
6. Generate successors of this node:
For each successor :
(a). If it has both been discovered / generated before i.e., it is not on OPEN, evaluate this node by applying the
heuristic function, add it to the OPEN and record its parent.
(b). If it has been discovered / generated before, change the parent if the new path is better than the previous one. In
that case update the cost of getting to this node and to any successors that this node may already have.
7. Reorder the list OPEN, according to the heuristic merit.
8. Go to step 3.



Example
In this example, each node has a heuristic value showing the estimated cost of getting to a
solution from this node. The example shows part of the search process using best first search.



Explanation
Fig. 1 : A is the starting node
Fig. 2 : Generate its successors B and C
Fig. 3 : As the estimated goal distance of C is less so expand C to find its successors d and e.
Fig. 4 : Now D has lesser estimated goal distance i.e., 4 , so expand D to generate F and G with
distance 9 and 11 respectively.
Fig. 5 : Now among all the nodes which have been discovered but yet not expanded B has the
smallest estimated goal distance i.e., 8, so now backtrack and expand B and so on.

Best first searches will always find good paths to a goal node if there is any. But it requires a
good heuristic function for better estimation of the distance to a goal node.



Advantages:
o

Best first search can switch between BFS and DFS by gaining the advantages of both the
algorithms.

o

This algorithm is more efficient than BFS and DFS algorithms.

Disadvantages:
o

It can behave as an unguided depth-first search in the worst case scenario.

o

It can get stuck in a loop as DFS.

o

This algorithm is not optimal.

Variants of Best First Search
1. The two variants of Best First Search are Greedy Best First Search and A* Best First Search. The Greedy BFS
algorithm selects the path which appears to be the best, it can be known as the combination of depth-first search
and breadth-first search. Greedy BFS makes use of Heuristic function and search and allows us to take advantages
of both algorithms.
2. There are various ways to identify the ‘BEST’ node for traversal and accordingly there are various flavours of
BFS algorithm with different heuristic evaluation functions f(n). We will cover two most popular versions of the
algorithm in this blog, namely Greedy Best First Search and A* Best First Search.



Artificial Intelligence

BCom

Savitribai Phule Pune University

Electrical Measurements and Instrumentation (BE/BTech - EE) BE/BTech-Electrical Engineering 3rd Semester 2023 SPPU

3rd Semester

Electrical engineering is a field of engineering that generally deals with the study and application of electricity electronics and electromagnetism This field first became an identifiable occupation in the latter half of the 19th century after commercialization of the electric telegraph the telephone and electric power distribution and use Subsequently broadcasting and recording media made electronics part of daily life The invention of the transistor and subsequently the integrated circuit brought down the cost of electronics to the point where they can be used in almost any household object

Electrical Engineering

Electrical Measurements and Instrumentation

Dr. A.P.J. Abdul Kalam Technical University

Engineering Mechanics (BE/BTech - CE) BE/BTech-Civil Engineering 3rd Semester 2023 AKTU

Civil Engineering

Engineering Mechanics

Visvesvaraya Technological University

Strength of Materials (BE/BTech - CE) BE/BTech-Civil Engineering 3rd Semester 2023 Vtu

Strength of Materials

Delhi University

Organisational Behavior (BCom - BCom) BCom-BCom 5th Semester 2023 DU

5th Semester

The Bachelor of Commerce degree is designed to provide students with a wide range of managerial skills, while building competence in a particular area of business (see aside). Most universities, therefore, plan the degree such that in addition to their major, students are exposed to general business principles, taking courses in accounting, finance, economics, actuarial studies, business management, human resources and marketing;

Organisational Behavior

Kerala University

Financial Accounting BCom-BCom- 2nd Semester 2015 KU

2nd Semester

Financial Accounting

Gujarat Technological University

Database Management Systems (BE/BTech - CE) BE/BTech-Computer Engineering 3rd Semester 2016 GTU

Computer Engineering

Database Management Systems

ANALOG CIRCUIT DESIGN (BE/BTech - ECE) BE/BTech-Electronics and Communication Engineering 4th Semester 2020 GTU

4th Semester

Electronics and Communication Engineering

ANALOG CIRCUIT DESIGN

APJ Abdul Kalam Technological University

Cryogenic Engineering (BE/BTech - MECH) BE/BTech-Mechanical Engineering 7th Semester 2020 KTU

7th Semester

Mechanical Engineering

Cryogenic Engineering

Anna University

Jawaharlal Nehru Technological University

Mumbai University

Rajiv Gandhi Proudyogiki Vishwavidyalaya

Bangalore University

Biju Patnaik University of Technology is a public state university located in Rourkela, Odisha, India.

Biju Patnaik University of Technology Rourkela Odisha

Madras University

Rajasthan Technical University is an affiliating university in Kota in the state of Rajasthan, India. It was established in 2006 by the Government of Rajasthan to enhance technical education in the state.

Rajasthan Technical University

Mysore University

Computational science and engineering CSE is a relatively new discipline that deals with the development and application of computational models and simulations often coupled with high-performance computing to solve complex physical problems arising in engineering analysis and design computational engineering as well as natural phenomena computational science CSE has been described as the third mode of discovery next to theory and experimentation 1 In many fields computer simulation is integral and therefore essential to business and research Computer simulation provides the capability to enter fields that are either inaccessible to traditional experimentation or where carrying out traditional empirical inquiries is prohibitively expensive CSE should neither be confused with pure computer science nor with computer engineering although a wide domain in the former is used in CSE e g certain algorithms data structures parallel programming high performance computing and some problems in the latter can be modeled and solved with CSE methods as an application area