Chapter 2 BUSINESS SOFTWARE MODELS

Leave approval using Joget

Figure 0.1: Leave approval using Joget

This chapter will explore some common approaches used to model the network of interactions that occur for business processes. These models not only help to provide deeper understanding of the nature of a business process but can facilating the development of systems to collect and analyze the data associated with the process.

2.1 Business Process Model (BPM)

There are many good reasons for using BPMN to model business processes. (Camunda Corporation 2018b)

  • Recognized Standard: BPMN is owned by an institution and is supported by many software products. Third party BPMN editors are available in the form of desktop apps like yEd (yWorks 2018) or online services like Camunda. (Camunda Corporation 2018a)
  • Simplicity: BPMN is based on a system of graphic symbols that easy to learn.
  • Power of expression: BPMN reduces descriptions of complex process work flows to a graphic model that is easy to grasp.
  • Implementation in IT: BPMN was developed to support technical implementation of processes (“Process Automation”). The more important IT becomes in a company, the more helpful BPMN can be, especially when process changes can be accomplished by a simple change of line.

2.1.1 A simple example

A BPMN model described a process from the beginning (a light or green circle) to the end (a dark red circle). Blocks of tasks leading to key events are specified in sequential order.

2.1.2 Notation

Naming conventions help to improve the readability of the process:

  • Tasks:

    • shown as a rounded rectangle
    • described as a [verb] + [object]
    • Acquire groceries is better than first take care of shopping for groceries
  • Events:

    • description of milestones and achievements
    • described as something that has already happened
    • hunger noticed is better when I begin to feel hungry

2.1.3 Symbols

BMP Software provide a pallette of objects to describe various aspects of a process.

yEd BPMN Symbol Palette

yEd BPMN Symbol Palette

Cawemo BPMN Symbol Palette

Cawemo BPMN Symbol Palette

Symbol Description
Start Event: Start of the process chain
End Event: The end of the process chain
Event Message Catch: wait for a message event
Event Message Throw: sending a message event
Task: Work to be done
XOR Gateway: choice of a action stream
Parallel Gateway: initiate simulataneous action stream
Swim lanes: separate the process by roles or actors

2.1.4 Sample Business Process Models

Order Fulfillment Processing

Order Fulfillment Processing

Book Checkout at the Library

Book Checkout at the Library

Pizza ordering

Pizza ordering

Pizza shop

Pizza shop

Correcting a bug in process flow

Identify and correct the flaw in this process so that the grass can be weeded, cut and watered in that order but only as required.

Cutting the grass

Cutting the grass

2.2 BPMN Model Simulation

BP Model sumulators allow process designers to test their model. The general approach is to use a task generator that creates and processes tasks at rates equal to the measured performance in the work place. Data is collected to measure the rate of utilization and work flow at all stages of the model in order to identify issues like bottlenecks and irregularities in the work loads of individual employees. Simulation test are usually conducted in 3 phases:

Stage Description Purpose
Modeling Simple visual model of the business process Specify the individual roles and the business logic of the process
Simulation Run task generation and execution according to measured performance Test the model based on work place rates of service
Analysis Creates a dashboard of performance indicators Verifies process design; Identifies opportunities for process improvement; Helps to maximize employee utilization; Provides for performance-based estimates of cost

Online services such as http://www.bpsimulator.com provide a useful means for testing a process design through the display of the model, test results dashboard and performance indicators for each stage of the process. The design is actually a translation of a BPMN model into a Event-driven Process Chain (EPC). However, additional key details are required to quantify the capacity and number of resources available. These details are saved in the attributes for each node as shown in the next section.

2.2.1 BP Simulator Model Components

The following table is adapted from the online help of BPSimulation. (Business Process Simulator 2018)

Object Description Example
Function: Set of targeted actions to be performed by one or more executors in one role
Repair of water supply; Acceptance payment; Sending a message
Execute: Position or role of those responsible for the execution of the function Motorman; Board member
Resource: Service or tools needed to perform the function
Machine; tool; Software
Tasks Generator: Generator global tasks of the business process of a certain type with a certain interval for the simulation purposes
Client request for a loan; Received customer complaint
Checkpoint: Auxiliary element for monitoring the process parameters at different stages its execution and control of tasks flow
Completing the approval stage; Completion of the process because of inconsistencies detected
Event: Cause or an intangible result of a function
Client’s visit; An error was detected
Regulate: Regulate document directly related to the order, conditions or results of the function
Manuals; Federal Law
Input: Material or information necessary to perform the function
Form; Statement
Output: Material or information generated or acquired additional properties as a result of the function
Part; Conclusion
Procedure: Set of performance features for a particular purpose
Applications processing; Approval of documentation
Comment: Auxiliary element model for clarifications or comments
Temporary condition; Proposed improvements

2.2.2 Linking objects together

All objects in the model should be at least one link to another object. To create a link between objects, you must first double-click on the object - the source of links, and then click on the object - the recipient, link will be created with an arrow on the side of the second object. Link means a direct impact or relationship of one object from another. Not all objects can be linked to each other. The group of objects: Tasks Generator, Function, Events, Procedure and Check Point can be suppliers (predecessors) or consumers (followers) of each other. Other objects only as the impact on function, as shown below the diagram:

Linking of Objects

Linking of Objects

With this extra data it is possible to simulate a day at work. The statistics collected help to pinpoint bottlenecks and limiting resources. The system provides a dashboard to summarize the results.

Dashboard of Test Results

Dashboard of Test Results

The model uses generators to simulate the volume of the demand for needs. Data comes from the functions and key check points of the model that monitor the workflow that passes these nodes. The executor nodes determine the capacity of the system. Performance is varied by changing the number of individuals in the role of executors.

Performance indicators

Performance indicators

2.2.3 An example: A Petrol Station**

Starting with the BPMN of a simple model of the processes behind getting gas at the petrol station.

The Gas Station

The Gas Station

results in a simulated model within the BPSimulator.

Getting Fuel Simulatation

Getting Fuel Simulatation

The simulation was run in the scenario of only have one cashier, one attendant, one gasohol pump, one diesel pump and 290 customers who arrive.

Starting Ending Number Hourly Rate
6:00 8:59 90 30
9:00 14:59 90 15
15:00 18:59 90 25
19:00 20:00 20 10

As shown in the dashboard, the average queue is 16 min.

Dashboard for Getting Fuel

Dashboard for Getting Fuel

Exercise: Improving performance of a petrol station

Using the sample model of a petrol station, determine a proper mix of men and machines that will reduce the queue time to less than 2 mins at the minimum cost.

2.3 Enterprise Resource (ERP)

The purpose of Enterprise Resource Planning (ERP) is to harness business data in a way that allows integrated management of core business processes. This business-management software is typically designed as a suite of integrated applications which collect, store, manage, and interpret data from a wide range of business activities. By managing the critical information of all business processes, ERP provides opportunities to support data-driven management decisions is such areas as cash flow, resources usage, inventory of raw materials, and the status of business commitments such as project milestones, orders fulfilment, purchase order payments, and staff compensation. The system facilitates the sharing of data across divisions of the business, such as manufacturing, purchasing, sales, accounting, and human resources.

2.3.1 Building Blocks

ODOO ERP Modules

ODOO ERP Modules

2.3.2 ProjectFedena.com: an example of an ERP

Project Fedena was conceived as a project to easily manage all campus records of schools and campuses and was implemented as a ERP system written in Ruby on Rails. The project was originally developed at Foradian Technologies but is now maintained by the open source community.1

Business System Software Development

Business System Software Development

2.3.3 The MVC Framework

  • Model: Defines the structure and nature of data used by the system includes permissions, validation and list of field attributes.
  • View: Renders outputs according to the limitations of the media such as web, email, sms, mobile, graphic image, json and xml.
  • Controller: Parses the user request into data queries and passes the response to the appropriate view. User requests are generally variants of the standard types of database functions: create, show, edit, update and delete.
  • Helpers: calculates basic conversions including support for foreign languages.
MVC Communications

MVC Communications

The Model implements the ERD. This is example comes from the Subject Model class definition.

belongs_to :batch
belongs_to :elective_group
has_many :timetable_entries,:foreign_key=>'subject_id'
has_many :employees_subjects
has_many :employees ,:through => :employees_subjects
has_many :students_subjects
has_many :students, :through => :students_subjects
has_many :grouped_exam_reports
has_and_belongs_to_many_with_deferred_save :fa_groups
validates_presence_of :name, :max_weekly_classes, :code,:batch_id
validates_presence_of :credit_hours,
   :if=>:check_grade_type
validates_numericality_of :max_weekly_classes
validates_numericality_of :amount,:allow_nil => true
validates_uniqueness_of :code, :case_sensitive => false

2.3.4 Unit testing

This is done through a series of Assertions that tried against the functions of a class:

class SimpleNumber

   def initialize(num)
       raise unless num.is_a?(Numeric)
       @x = num
   end

   def add(y)
      @x + y
   end

   def multiply(y)
       @x * y
   end
end
require_relative "simple_number"
require "test/unit"
     
class TestSimpleNumber < Test::Unit::TestCase
     
  def test_simple
    assert_equal(4, SimpleNumber.new(2).add(2) )
    assert_equal(6, SimpleNumber.new(2).multiply(3) )
  end    
end

2.3.5 Available assertions:

Assertion Description
assert( boolean, [message] ) True if boolean
assert_equal( expected, actual, [message] ) True if expected == actual
assert_not_equal( expected, actual, [message] ) True if expected != actual
assert_match( pattern, string, [message] ) True if string =~ pattern
assert_no_match( pattern, string, [message] ) True if string !~ pattern
assert_nil( object, [message] ) True if object == nil
assert_not_nil( object, [message] ) True if object != nil
assert_in_delta( expected_float, actual_float, delta, [message] ) True if (actual_float - expected_float).abs <= delta
assert_instance_of( class, object, [message] ) True if object.class == class
assert_kind_of( class, object, [message] ) True if object.kind_of?(class)
assert_same( expected, actual, [message]) True if actual.equal?( expected ).
assert_not_same( expected, actual, [message] ) True if not actual.equal?( expected ).
assert_raise( Exception,... ) {block} True if the block raises one of the listed exceptions.
assert_nothing_raised( Exception,...) {block} True if the block does not raise one of the listed exceptions.
assert_throws( expected_symbol, [message] ) {block}
assert_nothing_thrown( [message] ) {block} True if the block throws (or doesn’t) the expected_symbol.
assert_respond_to( object, method, [message] ) True if the object can respond to the given method.
assert_send( send_array, [message] ) True if the method sent to the object with the given arguments return true.
assert_operator( object1, operator, object2, [message] ) Compares the two objects with the given operator, passes if true

2.4 Behavior driven Development

Advantages:

  • Single source of truth: Specifications, tests and documentation are in the same document.
  • Living documentation: Because they’re automatically tested by Cucumber, your specifications are always bang up-to-date.
  • Customer focus: Cucumber helps business and IT collaborate to build a shared understanding of the business goals

(Cucumber 2019a) supports Behaviour-Driven Development(BDD) by reading executable specifications written in plain text and validating that the software does what those specifications say. The specifications consists of multiple examples, or scenarios written in Gherkin. (Cucumber 2019b)

The primary keywords are:

  • Feature
  • Example (Scenario and Scenario Outline are synonyms)
  • Steps: Given, When, Then, And, But
  • Background
  • Combinations (Examples is a synonum)

  • "..." (Doc Strings)
  • | (Data Tables)
  • @ (Tags)
  • # (Comments)

Examples follow this same pattern:

  • Describe an initial context (Given steps)
  • Describe an event (When steps)
  • Describe an expected outcome (Then steps)

2.4.1 A working example of specs in Cucumber

Feature: A simple banking program
        
Background:
   Given a customer named "DrBob"          
   And I have logged in as "DrBob"    

   Scenario: Balance checking   
   Given my account has a balance of $430   
   Then my account should show a balance of $430   
           
   Scenario: Account deposit   
   Given my account has a balance of $400   
   When I deposit $30   
   Then my account should show a balance of $430   
         
   Scenario: Account withdraw   
   Given my account has a balance of $500
   When I withdraw $70
   Then my account should show a balance of $430     
         
   Scenario Outline: deposits   
   Given there are <start> dollars in the account   
   When I deposit <added> dollars   
   Then I should have <left> dollars   
     
   Examples:    
     | start | added | left |   
     |    12 |   5   |    7 |   
     |    20 |   5   |   15 |   

References

Business Process Simulator. 2018. “Reference Guide.” https://www.bpsimulator.com/en/help.

Camunda Corporation. 2018a. “BPMN Editor.” https://camunda.com.

Camunda Corporation. 2018b. “BPMN Tutorial.” https://camunda.com/bpmn.

Cucumber. 2019a. “The Cucumber Reference.” https://cucumber.io/docs/cucumber/.

Cucumber. 2019b. “The Gherkin Reference.” https://cucumber.io/docs/gherkin/.

yWorks. 2018. “YEd Graph Editor.” https://www.yworks.com/products/yed.


  1. The Fedena source code can be found online at https://github.com/projectfedena/fedena