SIE 265 Warehouse Design Project - Group 10 (1)

Warehouse Design Project

Group 10:

Hassan Alsaleh, Keely Chiou, Elizabeth Hernandez, Chris Miller, Morgan Skillman, & Lorelei

Wong

SIE 265

Mike O’Brien

7 December 2016

Group 10 – Page 1

Table of Contents

Document 1 …………………………………………………………………………………… 02

Document 2 …………………………………………………………………………………… 08

Document 3 …………………………………………………………………………………… 11

Document 4 …………………………………………………………………………………… 26

Document 5 …………………………………………………………………………………… 30

Group 10 – Page 2


Document 1: Concept of Operations

Group 10:


Wong

SIE 265

Mike O’Brien

7 December 2016

Group 10 – Page 3

Table of Contents

1. Purpose of the Document ………………………………………………………………… 04

2. Scope of the Project ……………………………………………………………………… 04

3. Referenced Documents …………………………………………………………………… 04

4. Background ………………………………………………………………………………… 04

5. Concept for the Proposed System ………………………………………………………… 04

6. User-Oriented Operation Description ……………………………………………………… 05

7. Operational Needs ………………………………………………………………………… 05

8. System Overview ………………………………………………………………………… 05

9. Operational Environment ………………………………………………………………… 05

10. Support Environment ……………………………………………………………………… 05

11. Operational Scenarios ……………………………………………………………………… 06

12. Operational Impact ………………………………………………………………………… 06

13. Appendices ………………………………………………………………………………… 07

Group 10 – Page 4

1. Purpose of the Document

This document describes the characteristics of the proposed warehouse design project system

from the viewpoint of the system user. The intention of the document is to communicate all

quantitative and qualitative system characteristics to the audience, or stakeholders. The main

purpose of this document is to employ the capabilities of the proposed system to the given

requirements and to find the best model in terms of cost, time, and employee satisfaction.

The content of this document will cover and overview of the project, as well as the concept

and the operations of the system.

2. Scope of the Project

The end goal of the project is to propose three warehouse systems that optimize a picking and

packaging system for a single product company. The project will include a suggested

allocation of resources for a warehouse involving only the company that the warehouse

belongs to. Using MATLAB, Simulink models will simulate the different pick line

combinations that the group has chosen. Each combination will be scored on a zero to one

scale, based on performance, cost, and employee satisfaction, which will be weighed into a

final score that follows that same scale. The warehouse system simulation that produces the

highest score will be the recommended system.

3. Referenced Documents

Lecture materials were referenced for the document.

“8.4.5 Concept of Operations Template.” California Division | Federal Highway

Administration. N.p., 20 Sept. 2016. Web. 04 Dec. 2016.

4. Background

The company currently has available technology (manual and ARS lines) prepared, as well as

demand orders that are required every two hours in the day. The warehouse is effective as it

can complete orders, however, system designs could improve by lowering the operation cost

required to complete the work. The efficiency of the entire system will increase by making

the cost as low as possible, while still meeting all the demand drops throughout the day.

5. Concept for the Proposed System

The concept for the proposed system was structured by first, modelling the demands that are

dropped every two hours. A selected pick-line combination was then modelled in its own

subsystem, showing how the demand drops for the given technology combinations were met.

Scoring was then done using a separate subsystem. Through this grouping of subsystems,

technology combinations could be inserted and scored easily. Other options would be to

model the different technology options separately (one manual subsystem and one ARS

subsystem) to make these simulations easier to change out, but this way, the model is kept

more simple by not making complicated and interchangeable subsystems.

Group 10 – Page 5

6. User-Oriented Operation Description

The stakeholders include the company management, staff, employees, and investors. The

users of the project results are the company managers. The management will make the final

decision regarding allocation of resources. From there, staff and employees will adjust to any

schedule changes. The system may result in either workers needed to fulfill orders. Workers

promoted to operators will need to be trained to handle the ARS machines.

7. Operational Needs

The operational needs are dependent on 3 main categories: customers, stakeholders, and

warehouse system. Customers must be attracted by the satisfaction which the warehouse

provides, and can be met by finishing dropped orders on time, and by minimizing production

costs. Stakeholders, on the other hand, fund the company to make the warehouse running. To

get stakeholders, a great deal of analysis of the system, cost, and profit must be done. Lastly,

the warehouse system must have the best score, while also considering employee happiness.

8. System Overview

The scope of the system is based upon operational cost, capital cost, preferred shift time, and

whether orders are finished within 2 hours. The customers then must focus on the cost of

packaging orders on time. The main goal of the system in terms of the user is finishing orders

quickly and cost efficiently. The system operation can be described through the following

process. First, administration receives the number of orders that must be packaged. Second,

workers are hired, on a need-basis, based upon the order numbers, and the number of needed

pick lines are determined. Lastly, workers should finish orders on time, an ideal, so machines

can be temporarily shut down earlier, to save running costs. The line of communication in

this scenario would be the administration, which links the workers and customers.

9. Operational Environment

The environment of the system depends upon number of orders, overall operational costs, as

well as employee shift satisfaction. Ideally, employees want to work from 8 AM to 4 PM.

Employees must be trained for this kind of work and must have good experience in dealing

with environmental circumstances. The lower the overall cost for production, the better. In

addition, as orders are completed, the system will shut down to further help lower operational

cost. On the other hand, the number of orders would make a difference on the cost and profit,

because as the number of orders increases, the higher the employee demand us, thus

increasing the running cost and capital cost (8.4.5 Concept of Operations Template).

10. Support Environment

The physical support environment includes facilities, utilities, equipment, and the system

hardware and software. The facilities consist of both the administration and its workers. The

administration deals with the system hardware and software, as well as financials (salaries

Group 10 – Page 6

and costs). The utilities are always in favor of the customers, as better utilities will provide

more customers. Utilities consist of freight, quality of packaging, as well as customer service.

The equipment needed for running the systems are the lines (manual and ARS, and a plan).

11. Operational Scenarios

The demand, i.e. the orders, drop to the warehouse every two hours throughout the day every

day. When orders come in, employees on shift begin to work on the first manual line.

However, if there are more than four employees on shift, since there can only be a maximum

of four operators on a line at a time, the second manual line is turned on to operate. In the

case that more than eight operators show up to a shift, operators shall be sent home until the

total number of employees on shift reaches eight or less. When employees have completed

the existing orders and are waiting for the next demand to drop, they will be instructed to

organize and clean in preparation for the next round. Maintenance to both manual lines is

expected to be done throughout the day with check-ups at least once every two weeks.

If by any reason a new demand drops before the previous orders are completed, employees

are expected to continue working on the previous orders. They are not to start working on the

new demand until they have completed all other orders. Employees are expected to keep

record of demands drops and completion time, and report this data and information monthly.

In case of a failure with one of the manual lines, all employees will relocate to the working

line. If there are more than four employees on shift, the remaining employees are expected to

examine the failure and contact the correct people to fix it or else take care of it themselves

(depending on what the issue that brought upon the failure is). Otherwise all employees are

expected to continue working on the orders until they are finished with the current orders

(unless the problem is severe enough to require immediate attention or evacuation).

12. Operational Impact

Company Management

Orders are dropped every 2 hours around the clock on even hours. Employees are first

directed to a single line, and fill it up. If necessary, the rest of the employees will be directed

to the second line. Each employee can complete 240 orders in a 2-hour period on the manual

line. If there are more than 960 orders being dropped at that time, 960 orders will go to the

first line with 4 pickers, and the remaining orders and pickers will populate the second line. If

the pickers on shift complete the dropped orders before the end of the 2-hour period, the line

will be turned off to minimize costs. Throughout this system, there is only one 8-hour shift

(the peak hours shift) where 8 workers will be needed to work, whereas for the other 2 8-hour

shifts only one worker will be needed. During this peak hour shift, both lines may need to be

run, based upon the number of orders dropped at the beginning of each 2-hour period.

Group 10 – Page 7

Employees

Shifts will be scheduled between 10 PM-6 AM, 6 AM-2 PM, and 2-10 PM. The 2-10 PM

shift will be the shift that will have 8 employees, while the other two shifts will only have

one worker scheduled. This is because peak hours for dropped orders occur between 4 and 10

PM. Seeing as this shift doesn’t occur during preferred work hours, employees will be rotated

between the different shifts so everyone will have a shared responsibility and fairness for the

graveyard shifts. Employees will not be required as of now, to be cross trained on manual

and ARS lines. The proposed design only requires employees to be trained on manual

operations. When order are dropped at the start of every even hour, up to 4 pickers are

assigned to a single line with up to 240 orders per picker being placed in that line’s queue. A

maximum of 8 workers can be on shift at once, and can be split evenly between the two lines

if necessary. When all orders are complete, lines are shut off in order to minimize costs.

Investors

The proposed system of 2 manual lines will not impact the budget for capital costs. This

allows investors to use allocate money originally designated for warehouse design elsewhere

within the company that could also use improvements. This dual manual line system design

has the lowest operating costs compared to the other two proposed system designs. This

system aims to maximize the efficiency of on-shift employees to complete the orders within

each 2-hour period. By doing this, customers are satisfied that orders are being fulfilled in a

timely manner, which will thus increase the reliability reputation of the company. A

company reliable in the eyes of customers will normally experience growth and profit

increases when correctly operated.

13. Appendices

The company warehouse currently uses ARS (automated Retrieval System) and Manual pick

lines. The company is able to determine the current demand levels. That is why the

warehouse system needed to restructure by talking to stakeholders to implement the most

desired system.

Group 10 – Page 8


Document 2: Requirements

Group 10:


Wong

SIE 265

Mike O’Brien

7 December 2016

Group 10 – Page 9

Statement of the System Requirements

Input-Output Functional = (TR, IR, OR, OTR, MR)

- TR = One day, measured every 2 hours

- IR = Units ordered & # of workers

- ITR = (Time scale, Units ordered) & (Time scale, # of workers)

- OR = Units ordered every 2 hours

- OTR = Units produced & Cost

- MR = ((Time scale, Units ordered), Units produced) & ((Time scale, # of workers), Cost)

SDR = (IORP, TKYP, IMP, UMP, TMP, STP)

Input-Output Functional (IORP)

- 1.0 TSS take in an input of number of orders every two hours throughout the day starting at

12 AM

- 1.1 TSS take in an input for the number of workers at any given time

- 1.2 TSS assign works to pick lines based on number of orders coming in

- 1.3 TSS output complete orders

- 1.3.1 TSS complete orders within 2 hours

Technology (TKYP)

- 2.0 The System may be built from 2 available technologies

- 2.0.1 Manual Line

- 2 orders per minute per person

- 2.0.2 ARS Line

- 5 orders per minute per person

- $15,000 capital cost for every line

Input-Output Performance (IMP)

- 3.0 TSS be judged based on the ability of finishing the orders within 2 hours

- 3.0.1 The percent of orders completed within 2 hours shall be scored by

SSF3(v, 0, 1, 0.75, 0.25)

- 3.1 TSS be based on

- IMP = Score(orders completed in 2 hours)

Utilization of Resources (UMP)

- 4.0 TSS be judged based on

- 4.0.1 Percent of workers on preferred shift (8 AM-4 PM)

- 4.0.1.1 Percent of workers on preferred shift is worth 20% of the UMP

- 4.0.1.2 Percent of workers on preferred shift shall be scored by

SSF3(v, 0, 1, 0.75, 0.25)

- 4.0.2 Capital Cost

Group 10 – Page 10

- 4.0.2.1 Capital cost is worth 50% of the UMP

- 4.0.2.2 Capital cost shall be scored by SSF9(v, 0, 45000, 15000, -1/7500)

- 4.0.3 Operating Cost

- 4.0.3.1 Operating cost is worth 30% of the UMP

- 4.0.3.2 Operating cost shall be scored by SSF&(v, 0, 2500, -1/1250)

- 4.1 TSS be judged based on

- UMP = Score(preferred shift)*0.2 + Score(capital cost)*0.5

+ Score(operating cost)*0.3

Trade-Off (TMP)

- 5.0 The trade-off shall be made based on a 67-33 split between IMP & UMP

- 5.0.1 Score = 2/3 (IMP) + 1/3 (UMP)

System Test Requirements (STP)

- 6.0 TSS be tested for 30 days after installation to determine if the performance estimates are

within 5% of estimates used in analysis



Document 3: System Design Concepts

Group 10:


Wong

SIE 265

Mike O’Brien

7 December 2016


The design requires that the system will pick and package single products after orders are

dropped every 2 hours throughout the day beginning at 12am. There are two possible types of

pick lines: a manual line and an automated line. Up to three pick lines can fit into the warehouse.

All lines will shut down when not in use and will not be running if there are no orders in their

queue. The company prefers that all orders be completed within 2 hours of being dropped into

the system.

Each line can hold up to four pickers or operators for the manual and automated lines

respectively. Each picker on manual lines can complete 2 orders every minute and each operator

on automated lines can complete 5 orders every minute. Manual lines cost $50/hour for power

while ARS lines cost $15,000/line to buy and $350/hour for power.

Workers must be scheduled in full 8 hour shifts and are paid $12/hr. During these 8 hours it is

assumed that the workers can be shifted between lines if needed.

Our focus for designing the three models is to maximize the efficiency of how many workers are

on shift at a time. It was assumed that because they have the ability to change lines partway

through each 2 hour period, they would also be cross trained and able to work both the manual

and ARS lines.

General Model Details

General model details stay relatively the same throughout the different designs with a few

exceptions or tweaked aspects relative to the specific design concept. Below in figure 1, the basic

outline for the models is displayed.

Figure 3.1 – General Model Outline

Figure 3.2 displays the incoming orders that are set to come in as a pulse generator every two

hours; at 0, 120, 360, etc. The orders in the pulse generator are being imported in from a linked

excel file. Note: the time scale on the x-axis reads as seconds, but is being treated as minutes.


Figure 3.2 – Units Ordered Input Signal

Figure 3.3 illustrates the different shifts throughout the day. The number of workers are coming

in from an excel file and are set as a signal either on or off for 8-hour periods with how many

workers are on shift.

Figure 3.3 – Shifts Input Signal

Figure 3.4 below displays the subsystem used to check for negative orders. Negative orders are

where workers technically could complete more orders than needed within the 2 hour periods

since there are different ratios/minute for manual and automated. This subsystem compares the

absolute value of orders completed to the total orders to see if the amount completed has


surpassed the how many are needed. If all the orders or more have been completed, then the

system will reset the amount completed to be equal to the amount needed for the 2 hour drop

period. When there are less orders than needed however, the system will continue to run and

have the orders reflect how many have been completed until all are completed.

Figure 3.4 – Subsystem to Check if There are Negative Orders

The operating cost for the workers’ wages is calculated using the subsystem in Figure 3.5. This is

calculated by taking the number of operators over the entire period of time, integrating these

values and multiplying this value by 12/60 ($12 per 60 minutes) to get the total wages.

Figure 3.5 – Operating Cost Subsystem

To calculate the percent of workers on preferred shift and percent of orders completed within the

given 2-hour block, the subsystem Score is used. Shown below in Figure 3.6, the amount of

initial orders, amount of finished orders, and number of operators are all inputs. There are also

two pulse generators set for the different times that orders are dropped. One pulse generator is

used to tell the system when new orders are being dropped and to determine whether all orders

have been completed in time. The other pulse generator signals the new 2-hour block and will

trigger the system to determine whether workers are on their preferred shift.


The percent of orders completed has a delay on the amount of initial orders to prevent

miscalculation in the situation where orders may not be completed until the very last minute

when new orders are being dropped. As the new orders arrive, an integrator accounts for them

and the pulse generator will signal the if-else statement to either determine if the orders are all

done or if there are still orders left. If there are still orders left at the beginning of each 2-hour

gap (before new orders are added in) the score subsystem will return a 0 for the completed orders

score. Otherwise, if all orders have been completed by the 2 hours, then the score will return a 1.

The percent of operators on shift is calculated by integrating how many operators there are

throughout the day and taking the average of how many were on their preferred shift. The pulse

generator will give a signal of 1 to begin each 2-hour block to the Start Hour Block state and

integrate the amount of pulses for the different time shifts. If it is the start of a 2-hour block, then

the number of operators will come through the if-else statement to be used. The Preferred Shift

Check state will return a 1 if the workers are in one of the preferred shift times and a 0 if the shift

is not a preferred shift. From there if the shift is preferred then the number of operators will

continue through that if-else statement and be integrated into the number of workers on preferred

shift, otherwise a 0 value will be added. After that the average of preferred shift workers to total

workers will be taken and output back into the main system.

Figure 3.6 – Percent Workers on Preferred Shift & Percent Orders Completed in 2 Hours

Figure 3.7 demonstrates the logic behind the shift check. The integrator prior to this state will

increase by one every 2 hours because of the pulse generator. Knowing this, preferred shifts are

going to be shifts 5-9 while shifts 1-4 and 10-12 are going to be the unpreferred shifts. This state


function checks whether the shift number is a preferred shift number and returns a 1 if it a shift

from 8am to 4pm or a 0 for the 4pm to 12am shifts.

Figure 3.7 - Preferred Shift Check

Unique Model Details

Design #1 (One ARS Line)

Figure 3.8 shows the overview of the ARS line subsystem. The inputs to the system are number

of operators and number of orders. These orders go into the ARS Line Pick to determine how

many orders are being completed at every time and calculate the operating cost of the line due to

running the line. It then goes into another system that checks to make sure the amount of orders

remaining is not negative. The outputs to the system are number of orders remaining, total

number of orders, number of orders completed and operational cost of running the line.

Figure 3.8 - ARS Line Overview

Figure 3.9 shows the ARS Line Pick System that calculates how many orders have been

completed and the operational cost of running the line. The inputs to this system are the number

of operators and the number of orders that still need to be completed. The number of orders that


need to be completed goes into a chart that determines whether the line is on or off. If it is on, it

returns a 1 and if it is off, it returns a 0. This is then multiplied by -5 to signify the number of

orders that can be completed by one person in one minute. This number is then multiplied by the

number of operators to calculate the number of orders being completed in that minute and this is

integrated over the entire time period to calculate the total number of orders completed.

Figure 3.9 - ARS Line Pick Subsystem

Figure 3.10 shows the logic behind whether the ARS line is on or off. The input into the system

is the number of orders remaining (q). If q is greater than 0, the line is on and the chart outputs a

1 (w). If q less than or equal to 0, the line is off and the chart outputs a 0 (w).

Figure 3.10 - ARS Line On/Off Logic

Design #2 (Two Manual Lines)

Figure 3.11 shows the overview of the two manual lines subsystem. The inputs to the system are

the number of operators and the number of orders. These orders go into the Manual Line Pick to


determine how many orders are being completed at every time and also calculating the operating

cost of the line due to running the line. It then goes into another system that checks to make sure

the amount of orders remaining is not negative. The outputs to the system are the number of

orders remaining, the total number of orders, the number of orders completed and the operational

cost of running the line.

Figure 3.11 - Two Manual Lines Overview

Figure 3.12 displays the MM Line Pick which is the subsystem used to calculate how many

orders are being completed in total and what the operating cost for that minute is. The integrators

will collect the total overall orders completed and overall costs as the system is running.

Figure 3.12 -Two Manual Lines Pick Subsystem


Figure 3.13 shows the logic behind whether no lines, one line or two lines are running. The

inputs to the chart are the number of orders remaining (q) and the number of operators (op). The

outputs to the system are the number of orders completed during a specific time by one person

(w) and the number of lines that are running at any given time (line). If q is equal to zero, no

lines are running and the system outputs w=0 and line=0. If q is greater than zero and op is less

than or equal to four, then one line is running and it outputs w=-2 and line=1. If q is greater than

zero and op is greater than four, then two lines are running and it outputs w=-2 and line=2.

Figure 3.13 - Two Manual Lines On/Off Logic

Design #3 (One Manual and One ARS Line)

For the Manual/ARS design, the ideal situation would be to complete all orders manually due to

low operational costs, however, the incoming number of orders sometimes outnumber the low

amount of orders that each worker can complete every two hours on the manual pick line. The

number of incoming orders will determine how many operators will go to each line.

A chart diagram will be printed and displayed in several easy-to-see places within the warehouse

with a range of values dictating how many orders and workers will go to each line. It will be easy

enough to read for employees to just count how many workers there are, check the amount of

orders dropped, and then look at where the categories intersect to see the specific breakdown.

Figure 3.14 shows the overview of the one ARS line and one manual line subsystem. The inputs

to the system are number of operators on shift and number of orders. The number of operators

goes into several subsystems and charts, that determine which pick operators will work at. Then


the numbers go into subsystems of their respective picks, and outputs of these subsystems (and

inputted number of orders) go into a subsystem that adds amount of completed orders together to

ensure that the amount of orders remaining does not go into negatives. The outputs of the system

are the number of orders remaining, total number of orders, and number of orders completed.

Since operation of the manual and ARS line have each been explained on Design #1 and #2, this

document portion will only discuss how this design determines which pick operators will work.

Figure 3.14 - One ARS, One Manual Overview

Figure 3.15 shows the section of the design’s overview that deals with the distribution of workers.

The inputted number of operators is multiplied by 240 to determine the maximum amount of

orders that can be completed in 2 hours manually since each operator on a manual line can

complete 2 orders per minute. This number is then compared to the inputted number of orders to

check if number of orders needed to be completed was less or equal to the max amount of orders

that can be completed in 2 hours manually. The “Can It All Be Done on Manual?” state flow

diagram then determines whether orders can be completed solely on manual with the number of

operators working, and the “If Yes” if block divvies up workers among both lines.

Figure 3.15 - Assigning Operators to Picks


Figure 3.16 shows the logic of whether all orders can be completed within two hours if all

workers were placed on the manual pick line. The inputs to the chart is the 2-minute pulse event

(myClock) and whether the number of orders is less than or equal to the max amount of manual

orders able to be completed within two hours or not (a==1 and a==0, respectively). The output of

this chart is whether the orders can in fact all be completed manually or not (x=1 and x=0,

respectively). After the initial state (START, 0), the chart checks whether the orders can be done

manually or not every two hours when the orders come in.

Figure 3.16 - “Can It All Be Done on Manual?” Logic

The outputs of the chart then go into an If Statement block. If output of the state flow diagram is

not equal to one, i.e. zero, then the path goes into the If Action Subsystem of the if action, which

is demonstrated in Figure 3.17 below. This subsystem is called “All Manual”, and the input is the

number of operators of shift (as demonstrated in Figure 3.15) while the outputs are the number of

operators on the manual pick line and number of operators on the ARS pick line. Since it is pre-

determined that all orders can be handled manually in two hours, then all operators on shift are

assigned to work on the manual pick line, while zero operators are assigned to the ARS pick line.

Figure 3.17 - If Statement Subsystem


However, if the state flow diagram of Figure 3.16 outputs a one, the path goes into the If Action

Subsystem of the else action, which is demonstrated in Figure 3.18 below. This subsystem is

called “Or How Many on Each Line?”, and the inputs are the maximum amount of orders that

can be completed manually within the 2-hour time frame and the inputted number of orders. The

latter number is divided by the former number to determine how many times greater the number

of orders is than the number of manageable orders.

Figure 3.18 - Else Statement Subsystem

This number then becomes the input (a) to the state flow diagram labelled “Assigning Operators

to ARS Line”, pictured in Figure 3.19 below. The output (and the states, coincidentally) of the

chart is the number of operators that will be assigned to the ARS line. If the number of orders is

less than one time larger than the max amount of manual orders (a < 1), then one operator is

assigned to the ARS pick line. If the number of orders greater than or equal to one time larger

and less than twice larger than the max amount of manual orders (a >= 1 && a < 2), then two

operators are assigned to the ARS line. If the number of orders greater than or equal to twice

larger and less than three times larger than the max amount of manual orders (a >= 2 && a < 3),

then three operators are assigned to the ARS line. If the number of orders greater than or equal to

three times larger than the max amount of manual orders (a >= 3), then four operators are

assigned to the ARS line. The pattern ends here since there can only be a maximum amount of

four workers on the ARS line at a time.


Figure 3.19 - “Assigning Operators to ARS Line” Logic

The outputted number of operators on the ARS Line then goes into yet another If Statement

block that does the simple algebraic manipulation of assigning the operators to each line.

Pictured below in Figure 3.20 is an example of the If Action Subsystem blocks, labelled “Four

on ARS”. In this else action port, four operators were determined to work on the ARS line. Four

operators are assigned to the ARS line and four is subtracted from the total number of operators,

and the remainder of operators go to the manual line. Similarly, in the “Three on ARS” If Action

Subsystem (not pictured), three operators are assigned to the ARS line and the remainder of the

total number of operators are sent to the manual line. In the “Two on ARS” If Action Subsystem

(not pictured), two operators are assigned to the ARS line and the remainder of the total number

of operators are sent to the manual line. Finally, in the “One on ARS” If Action Subsystem (not

pictured), one operator is assigned to the ARS line and the remainder of the total number of

operators are sent to the manual line.


Figure 3.20 - Example Subsystem of “Assigning Operators” Action Ports

After the operators are assigned to their respective lines, the manual and ARS lines work

independently (detailed descriptions on how each line works can be found under Design #1 and

Design #2), but their completed orders are added together and treated as one system.

Results

Figure 3.21 displays the results from each of the different proposed designs. All the lines

completed the required orders within 2 hours of being received, ergo all receiving a full score of

1 for the IMP value. UMP is composed of the number of workers on preferred shift, the

operating costs, and the capital costs associated with each model. The scores are shown on the

right-hand column in each design with values between 0 and 1. If a score of 0 is received that is a

very unfavorable score meanwhile a score of 1 is a full point score. The UMP is then calculated

by adding up the various associated sections with the corresponding weight to each part as

described in documents 2 and 4. TMP is then displayed as well, which is calculated using IMP

and UMP whose weights are described in the previously referenced documents also.

Figure 3.21 - Trade-Off Scores

Based off the scores received, IMP individually did not affect our overall decision because each

of the designs we created completed the necessary orders within each allotted 2-hour period.


The scores for the workers on preferred shifts was low across the board, due in part to the fact

that we have the schedule set based off how many workers will be needed during specific 8 hour

periods, not what their preferred shift is. The operating costs are calculated based off the power

costs and employee hourly wages accumulated throughout the day. The ARS & Manual lines

design had the lowest score for operating costs by far, probably since it costs much more to run

the ARS line rather just using the manual line. The capital costs were the same for the ARS and

ARS & Manual line designs because there is only one ARS line in each. The overall UMP scores

revealed that the purely Manual design had the best score by far while the other two designs

underperformed in this category.

Once the TMP scores were calculated, the overall scores across the board for each of the designs

were relatively good, but the Manual lines only design outperformed the others. With a score of

95.9% it was the most efficient of the three designs.

Taking all this information into account, we would recommend going with a double manual line

design for the warehouse. This design completes all orders in the given test case on time within 2

hours of being dropped. It also doesn’t add any capital cost to the budget so the only costs

affecting the design are going to be operating costs. With this design, their workers do not need

to be cross trained on both machines since there is only manual lines available and one line will

be used to max capacity before turning on the second line. Also, since there are only two lines

proposed, if the company’s business begins to grow and expansions are needed, then there is

room for another line to be added later.



Document 4: System Model (Scoring Functions)

Group 10:


Wong

SIE 265

Mike O’Brien

7 December 2016


Each alternative is compared based on the scoring subsystem (outlined in a red box) shown in

Figure 4.1. Figure 4.1 is the general schematic for each model.

Figure 4.1 – General Model Overview

The alternatives are each scored based on the scoring model shown in Figure 4.2. The Input-

Output Performance is calculated based on IMP = Score(orders completed in 2 hours). The

Utilization of Resources is calculated based on UMP = Score(preferred shift)*0.2 +

Score(capital cost)*0.5 + Score(operating cost)*0.3. The trade-off score is calculated based on

TMP = 2/3 (IMP) + 1/3 (UMP). The TMP for each alternative is compared and the alternative with

the highest score is the optimal design for the warehouse. All scores that make up the IMP and

UMP are calculated using the scoring functions shown in Figures 4.3-4.5.

Figure 4.2 – Scoring Subsystem


The score for the percent of orders completed in the 2 hours and the score for the percent of

workers on the preferred shift are represented by scoring function SSF3(v, 0, 1, 0.75, 0.25)

shown in Figure 4.3. The scoring function has a positive slope because the more orders

completed in a two hour period from when they arrived, and the higher percentage of workers on

the preferred shift, results in happier management and workers. The management team is happier

the higher the percentage of orders completed in two hours, so this results in a higher score. If

100% of orders are completed in two hours, this receives a score of 1. The workers are happier if

they are on the preferred shift (8 AM-4 PM) so this also results in a higher score. If 100% of the

workers are on the preferred shift, this receives a score of 1.

Figure 4.3 – Percent of Orders Filled / Percent of Workers on Preferred Shift Scoring

Function

The score for capital cost is represented by scoring function SSF(v, 0, 45000, 15000, -1/7500)

shown in Figure 4.4. This scoring function has a negative slope because the higher the cost, the

less happy the management team is. For example, the management team is happiest when the

capital cost is $0 so this results in a score of 1.

Figure 4.4 – Capital Cost Scoring Function

The score for operational cost is represented by scoring function SSF7(v, 0, 2500, -1/1250)

shown in Figure 4.5. This scoring function has a negative slope because the higher the cost, the


less happy the management team is. For example, the management team is happiest when the

operational cost is $0, so this results in a score of 1.

Figure 4.5 – Operational Cost Scoring Function



Document 5: Systems Engineering Management Plan

Group 10:


Wong

SIE 265

Mike O’Brien

7 December 2016


Scope of Work

Objective: The objective of this project is to propose three warehouse systems that optimize a

picking and packaging system for a single product company. Scoring functions based on the

simulations will be used to determine the recommended system.

List of Contributors:

Models (11/6/16 - 11/27/16)

- Lorelei, Morgan, & Elizabeth

Presentation (11/20/16 - 11/27/16)

- Hassan, Keely, Elizabeth, Chris, Morgan, & Lorelei

Document 1 (11/13/16 - 12/6/16)

- Sections 1-10 & 13: Hassan, Chris, & Keely

- Sections 11-12: Elizabeth, Morgan, & Lorelei

Document 2 (11/13/16 - 12/4/16)

- Hassan & Morgan

Document 3 (12/4/16 - 12/6/16)

- Morgan, Lorelei & Elizabeth

Document 4 (12/3/16 - 12/4/16)

- Morgan

Document 5 (12/14/16 - 12/6/16)

- Keely, Lorelei & Morgan

Editing and Formatting (12/4/16 - 12/6/16)

- Keely

Meeting Schedule


Contact Information

SIE 265 Warehouse Design Project - Group 10 (1)

Documents

Transcript of SIE 265 Warehouse Design Project - Group 10 (1)