# Optimal Bangla Keyboard Layout Using Association Rule Of Data Mining Md. Hijbul Alam, Abdul Kadar Muhammad Masum, Mohammad Mahadi Hassan And S M Kamruzzaman

Department of Computer Science & Engineering International Islamic University Chittagong, Chittagong-4203, Bangladesh Email: hijbul_bd@yahoo.com, akmmasum@yahoo.com, mahadi_cse@yahoo.com, smk_iiuc@yahoo.com

## Abstract

In this paper we present an optimal Bangla Keyboard Layout, which distributes the load equally on both hands so that maximizing the ease and minimizing the effort. Bangla alphabet has a large number of letters, for this it is difficult to type faster using Bangla keyboard. Our proposed keyboard will maximize the speed of operator as they can type with both hands parallel. Here we use the association rule of data mining to distribute the Bangla characters in the keyboard. First, we analyze the frequencies of data consisting of monograph, digraph and trigraph, which are derived from data wire-house, and then used association rule of data mining to distribute the Bangla characters in the layout. Finally, we propose a Bangla Keyboard Layout. Experimental results on several keyboard layout shows the effectiveness of the proposed approach with better performance.

Keywords: monograph, digraph, trigraph, association rule, data mining, hand switching, support, confidence. 

## 1. Introduction

The usefulness of computer is increasing rapidly. It is the fastest growing industry in the world. New invention of technologies makes it faster. The billions of instructions can be done within a second nowadays. But the technology of input device like keyboard has not been changed much. The typing speed is very slow in respect of computer's other devices. Its main cause is the complex and insufficient keyboard layout and human limitations [6] . A scientific keyboard layout with equal hands load and maximum hand-switching can reduce this problem. The use of Bangla s increasing day by day in everyday life. Specially in data entry and printing sector. But there is no scientific Bangla keyboard layout at present and very few research works have been done in this field. Data mining popularly referred to as Knowledge Discovery in Databases (KDD), is the automated extraction of patterns representing knowledge implicitly stored in large databases, data warehouses, and other massive information repositories. In this paper we have tried to design a Bangla keyboard layout using the association rule of data mining. We have collected the data from various Bangla documents and we have used the association rule to extract the association of Bangla letters each other. And finally we have designed a Bangla keyboard layout with equal hands load and maximum hand switching.

## 2. Mining Association **Rule**

Association rule mining finds interesting association or correlation relationships among a large set of data items. The discovery of interesting association relationships among huge amounts of transaction records can help in many decision-making processes. 

Let us consider the following assumptions for representing the Association rule in terms of mathematical representation, J = {i1, i2, … , im} be a set of items. D = Set of database transactions where each transaction T is a set of items such that T ⊆ J. 

Each transaction is associated with an identifier, called TID. **A, B** = Set of items. A transaction T is said to contain A if and only if A ⊆ T. An association rule is an implication of the form A ⇒ B, where A ⊂ J, B ⊂ J, and A ∩ B = ∅ The rule A ⇒ B holds in the transaction set D with support S, where S is the percentage of transaction in D that contain A ∪ B, i.e., Support (A ⇒ B) = P (A ∪ B). The rule A ⇒ B 
has confidence C in the transaction set D if C is the percentage of transaction in D containing A that also contain B, i.e., confidence (A ⇒ B) = P (BA) = 
[support count(A ∪ B) / support count(A)]. [1],[3]

## 3. Methodology:

At first we calculate the monograph, digraph from the frequencies of characters from the Bangla documents. 

And then we find the association of a character with the determined left hand typed letter sets and right hand typed letter sets according to association rule and distribute it in opposite side for better or maximize hand switching as described in the algorithm at section 4. Finally, we distribute the most frequent word closer to finger for easy and first access. Before stating the algorithm we have to explain some keyword in brief. The meaning of support and confidence is stated earlier in section 2. 

We introduce four new terms for our purpose. Left support of a letter means the cumulative support of the letter to the set of left sets letter. Left confidence 