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Page 1: Queueing Analysis
Page 2: Queueing Analysis

Flow of the presentation

Page 3: Queueing Analysis

Sector• Choice of Sector : Retail

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Pre analysis• Observation & Introduction• Observe Market Generally• Market Structure• Introduction• Rush hours• Days of Rush• Purchasing Cycle• 1st Week of the month• Ist Sunday• Eid Public Holidays Ramzan

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Situation Arriving Customers

Service Facility

Passage of customers through a retail outlet checkout

Shoppers Checkout/cash counters

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Problem FormulationProblem StatementWhy does the queues formed at chase up are too long during peak hours?Objective: Analysing the Bottle Neck at chase up’s cash counter during peak hours i.e. - weekends, - occasional holidays, - first week of every month- Seasonal SalesNeed of this analysis arises as we observe the unsystematic way of queuing at Chase.• We characterized our Queuing Analysis in terms of store

location i.e. Bahadurabad.

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• In order to analyse and solve the queuing management system at Chase up, we will use a single stage queuing model with multiple queues and multiple servers.

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Single stage queuing model with multiple queues and multiple parallel servers

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Characteristics of the model

Arrival Characteristics Size of the calling population?

- Infinite: The source of customers can be finite or infinite. For example, all people of a city or state (and others) could be the potential customers at a retail outlet. The number of people being very large, it can be taken to be infinite. Patterns of arriving? - Random: Arrivals are considered random when they are independent of one another and their occurrence cannot be predicted exactly. Behavior of the arrivals i.e. patient or balking?- Depends on time of the day or day of the week

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Characteristics of the model

Waiting Line CharacteristicsLength of line- InfiniteQueue discipline

- FIFO: (First in, First out): a customer that finds the service center busy goes to the end of the queue.

Service Facility CharacteristicsConfiguration of service system (no of servers and

phases)?- 10 servers; single phaseService time distribution (constant or random)?

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Chase Up• Opens at 11 am (Fridays – 3 pm)• Rush Timings start from 6 pm• Peak hours 9 pm – 11 pm• Foot fall - 200 -300 people at a time• Days : Friday, Saturday, Sunday• Layout : 7 grocery cash counters• 2 garments• 1 pharmacy

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Data Collection MethodsPrimary Data:

• Observations

• The observations for number of customers in a queue, their arrival-time and departure-time were taken without distracting the employees. The whole procedure of the service unit each day was observed and recorded using a time-watch during the same time period for each day.• Telephonic interview• Face to face (customer interaction)

• Qualitative Data:•

• Quantitative Data• Waiting lines

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Variables

• λ= Mean number of customer arrivals per time period

• µ= Mean number of customers served per time period

• ρ= Utilization factor for the system• L= Average number of customers in the system• Lq= Average number of customers waiting in the

system• W= Average time each customer spends in the

system• Wq = Average time each customer spends in the

queue

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Present System• λ= 400 customers arrive per hour on average• µ= 41 customers served per hour on average by

each counter

Operating Characteristics

Present System

L 46 customers

Lq 37 customers

W 6.94 mins

Wq 5.48 mins

U 0.98

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Alternatives

Alternative 1:Mobile cash counter to accommodate additional customers during peak hours through effective utilization of space.• λ= 400 customers arrive per hour on average• µ= 39 customers served per hour on average by

each counterOperating Characteristics Alternative 1

L 21 customersLq 10 customers

W 3.12minsWq 1.65mins

U 0.89

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Cost-Benefit Analysis (Alternative-1)

Assumption: Each one-minute reduction in customer waiting time avoids Rs.1000 in lost sales per week.Cost: Mobile cash counter = PKR 15000 (one-time cost)- No additional costs in terms of hiring additional staff, will be managed by an existing employee.Benefit:Reduction in minutes= 5.48-3.25=2.23 minutesPer week extra savings = 2.23 * 1000= Rs. 2230Mobile Cash Counter is paid off in 7 weeks

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Alternative 2:2 additional cash counters.• λ= 400 customers arrive per hour on average• µ= 37 customers served per hour on average by

each counterOperating Characteristics

Alternative 2

L 15 customersLq 4 customers

W 2.19minsWq 0.8mins

U 0.87

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Cost-Benefit Analysis (Alternative-2)• Cost of a new counter= Rs25000 i.e. Rs50000 for

2 counters• Cost of additional employee= Rs1000/week i.e.

Rs2000 for 2 employees• Reduction in minutes= 5.48-0.8=4.68 minutes• Weekly Savings= 4.68*1000= Rs4680-

2000=Rs2680• Counters are paid off in 50000/2680= 19 weeksAfter Rs50000 recovered, alternative 2 would provide Rs2680-2230= Rs450 more savings per week.

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Alternative 2:• Happy Hour i.e. 20% additional discount on

all discounted items on weekends morning i.e. 12pm-3pm.

• Cost- Have to forgive the Profit Margin from 5Additional 5% of cost

Benefit:

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Solution

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Managerial Implications

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Generalization

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