INTERNATIONAL JOURNAL OF SOCIAL SERVICE AND
RESEARCH |
Lukas Susanto
PGRI Madiun University, Madiun,
Indonesia
Email: [email protected]
Abstract
Tempe chips
are a superior product in Ngawi Regency. Some
home-industries of tempe chips have also been
negatively affected by the COVID-19 pandemic, including a decline in sales,
difficulties in raw materials, capital problems and obstacles to the production
process. Various efforts to increase sales have been carried out both through
mentoring and research, among others by trying to do online marketing and
designing better tempe chips packaging designs, but
there has been no good planning on product composition. From the interview, it
is known that in determining the composition of the many packaging units of tempe chips and determining the selling price per unit, it
is only based on experience while running a business and no optimization method
has been used. �Therefore, it is necessary
to apply an optimization method to obtain maximum profit. In this research, we
try to determine the number of production units for each type of tempe chips packaging that produces maximum profit and
determine efficiency in the use of cost and time resources. Data collection
techniques are carried out by observation and interviews. �The simplex method was used to solve this research
problem. �We found that the home industry reached the maximum profit
at 661 units of small packaging and 269 units of large packaging which gained
IDR 23600 and time was reduced to 9.29 h.
Keywords: maximizing profits; number of production
units; simplex method
Received 7
October 2021, Revised 3 November 2021, Accepted 2021
INTRODUCTION
As we know, the COVID-19 pandemic has had a negative
impact on UMKM, especially in the East Java region, including a decline in
sales, difficulties in raw materials, capital problems to production process
barriers. Various efforts to increase sales have been carried out both through
mentoring and research, among others by trying to do online marketing (Imron
& Nurdian, 2021), and tempe
chips packaging designs (Jessica, at al. 2015).
To maintain its existence, especially during the COVID-19
pandemic, companies are required to be more observant in dealing with all
existing problems and other problems that may arise. Analysis related to the
composition of the number of production units, the efficiency of the production
capital used, determining the selling price and optimizing other resources
owned by the company need to be carried out carefully and thoroughly.
Determining the composition of the number of production units in a company is the
main thing that needs attention for planning, because this has a direct effect
on the company's profit.
Determining the composition of the number of production
units to maximize company profits by looking at the company's limited resources
can be solved using a linear programming model. There are several ways to solve
problems with a linear programming model, including the simplex method. The
Simplex method is the solution of a linear program model whose solution is
presented in the form of a graph before which calculations were carried out to
find common ground on each axis. The general procedure is to transform a
descriptive situation into a linear programming problem by determining the
variables, constants, objective functions, and constraints so that the problem
can be presented in graphical form and the solution interpreted (Suwirmayanti, 2017).
A company and all its resources such as energy, time,
money and others, in order to achieve real growth requires professional
management, with the aim of obtaining maximum profit while using minimal
resources (production capital). This is nothing but one of the optimization
problems in operations research (Chandra, 2015).
This research was conducted in the home industry
"ENY", in Ngawi Regency, East Java, which
daily produces Tempe Chips, which are served in 3 packages, namely small
packages, medium packages and large packages. During the COVID-19 pandemic,
this company continued to carry out the production process every day, but by
reducing the production volume, namely 600 small packaging units, 80 medium packaging
units and 250 large packaging units. At the time of observation, information
was obtained that the production volume was fixed every day, and production
costs were also relatively fixed. The composition of the number of units for
each type of packaging of tempe chips produced, and the
selling price of the product per unit, are determined on the basis of
experience while running the business, so there is no optimal planning or
analysis method.
Based on this condition, the researcher wants to help the
owner of the company to make a plan about determining the composition of the
number of units for each type of packaging of tempe
chips that must be produced so that the company obtains maximum profit, while
taking into account the limited resources available.
The purpose of this study is to solve the problems faced
by the company, by discussing the determination of the number of small packaging
units, medium packaging and large packaging that must be produced so that the
profit is maximum, calculating the maximum profit value in one day, calculating
the efficiency (decrease) in resource use. limited, namely production capital
and production time.
Some of the limitations and assumptions in this study are
the total number of units of the three types of packaging tempe
chips produced is the largest equal to the total number of units produced
before the study, the total production time is the largest equal to the total
production time before the study, the production capital is at most equal to
the capital production before the study, the results of calculating the maximum
profit value will be achieved with the assumption that all products are sold
out.
The results of this study are expected to provide
benefits, input and suggestions, especially for company owners in making
decisions to change the composition of many production units for each type of tempe chip packaging, in order to obtain maximum profit.
The problem faced by this company is the Linear
Programming Problem (LPP). Because the problem consists of 3 decision
variables, the simplex method in a linear program is the right method to solve
the problems experienced by the company, by decomposition of the many product
units produced based on the limited resources available, with the aim of
obtaining maximum profit (Christian, 2013).
Linear programming is a mathematical method with linear
characteristics to find an optimal solution by maximizing or minimizing the
objective function against the set of constraints (Budiasih, 2013).
The simplex method is a mathematical procedure to find the
optimal solution of a linear programming problem based on an iterative process (Aulia et al., 2013).
Linear programming is an optimization technique used to
obtain the most optimal solution for a real world
problem. There are simplex method. The simplex method
provides two methods to solve linear programming problems, namely the graphical
method and the a systematic way of examining the
vertices of the feasible region to determine the optimal value of the objective
function. The "linprog" function in Mat Lab
can be used to solve linear programming problems (Velinov & Gicev, 2018).
One method that can be used to solve LPP is the Simplex Algorithm in Linear
Programs (Sukanta, 2016).
The following are several studies related to the
application of the simplex method for the purpose of optimizing the completion
of LPP. (Rumetna et al., 2020)
conducted a study entitled �Optimizing Revenue Making Banners and Billboards
Using the Simplex Method (Case Study: Shiau Printing Printing Business)�, from the analysis it is stated that Shiau Printing Printing can get a
maximum profit of Rp. 15,000,000,- every month. (Fardiana, 2013)
conducted a study entitled "Maximizing Profits at Martabak
Doni Cake Shop with the Simplex Method", the
results of data analysis are that the optimal combination of inputs obtained,
will provide a maximum profit of Rp. 106,817,-. (Budiyanto, Mujiharjo, & Umroh, 2017)
conducted a study with the title "Profit Maximization in the Roti Bunda Bakery Company Using the Simple Method" the results
of the research were optimizing the use of resources, it would be able to increase
profits from Rp. 1,663,914,- per week to Rp. 2,286,049,- per week. Akram, A. Sahari, and AI Jaya conducted a study entitled
"Optimizing the Bread Production Method Using Branch And
Bound" method Branch And Bound is solving technique that can be used not
only on the LPP, but can be applied to a wide range of issues different. This
method is used together with the simplex method (Akram, Sahari, & Jaya, 2016).
METHOD
Thinking Framework
Stages in the process of solving this research problem
consist of:
1. Identification
of research variables, profit functions, and limiting functions,
2. Compiling
the problem into a mathematical model, in this case the form of linear program
modeling,
3. Changing
the mathematical model into a table simplex,
4. Perform
an iterative process of solving with the algorithm in the simplex method, until
the optimal table is obtained,
5. Presenting
the optimal solution in mathematical language,
6. Interpreting
the optimal solution of the research problem.
Data Collection Procedure
Collection
was carried out by direct observation to the location and interviews, which
were divided into two stages, as follows:
1. Preliminary
observation, this stage was carried out to see firsthand the general condition
of the company, and notify the research objectives to the company owner, so
that the company understands the usefulness of the research results later,
besides that at this preliminary stage the researcher can give a message to
prepare data related to the data needed in research,
2. Data
collection, at this stage interviews and clarification of the data that have
been collected prepared by the owner, with the hope that detailed and in-depth
information can be obtained, related to the analysis plan to be carried out.
Data Analysis Techniques
1. Describing
the Data.
In this step, the transformation process is carried out
from raw data from interviews, which are all materials and resources needed in
the production process, into data that is ready for mathematical modeling.
2. The
Identify Variables
making:
𝑋1
= Many units small packaging should be produced
𝑋2
= Many units medium packaging should be produced
𝑋3
= Many units large packaging should be produced
3. Constraints
total unit Production: 𝑎11𝑋1 + 𝑎12𝑋2 + 𝑎13𝑋3� 𝑏 ≤1 (aij = 1, for every i and j)
Total cost: 𝑎21𝑋1 + 𝑎22𝑋2 + 𝑎23𝑋3�� ≤2
Total time: 𝑎31𝑋1 + 𝑎32𝑋2 + 𝑎33𝑋3�� ≤3
Functions Advantages 𝑍 = 𝑐1𝑋1 + 𝑐2𝑋2 + 𝑐3𝑋3
mathematical models of research problems in general:
Specifies 𝑋1,
𝑋2,
and 𝑋3
with constraints:
𝑎11𝑋1 + 𝑎12𝑋2 + 𝑎13𝑋3�� ≤1 (aij = 1,
for every i and j)
𝑎21𝑋1 + 𝑎22𝑋2 + 𝑎23𝑋3�� ≤2
𝑎31𝑋1 + 𝑎32𝑋2 + 𝑎33𝑋3�� ≤3
so that the values 𝑋1, 𝑋2,
and 𝑋3
obtained will maximize the profit function 𝑍 = 𝑐1𝑋1 + 𝑐2𝑋2 + 𝑐3𝑋3.
Furthermore, this mathematical model will be solved by the simplex method.
To complete the LPP the simplex method in
the case of maximizing, mathematical models of LPP expressed as linear as
follows:
Determine
Which
satisfy the constraint: 𝐴𝑚�𝑛𝑋𝑛�1 (≤, =)�1
Optimizing
[𝑍1
� 1 = 𝐶1
�𝑛
𝑛𝑋�1].
Here are the steps to resolve the case of LPP to maximize
the objective function in the simplex method:
1. Turn
all obstacles to the canonical form by adding a variable (variable) Slack's.
The existing slack variables are added to the target function and given a
coefficient of 0, Step 1 causes the matrix A to be of size mx (n+m) and contains an identity matrix of order m. Continue
by compiling the initial simplex table,
2. Determine
the key column, which is to determine the incoming variable to be the new base
variable.
J column is the key
column ↔(𝑍𝑗 - 𝐶𝑗)>0
smallest,
3. Determine
the key lines that define variables which should be out long base being
replaced by a new variable basis. I line is line ↔ key index i> 0, the smallest,
4. 𝑖𝑗𝑎
called a key element, doing surgery rows: row i i new = old / 𝑖𝑗𝑎
5. Perform
row operations on the other lines so that the elements sekolom
the key element to 0,
6. table
↔ were optimal for all j values(𝑍𝑗 - 𝐶𝑗)>0,
7. If
the table is not optimal return to step 2. (Sriwasito, Surarso, & Sarwoko, 2011).
To avoid data analysis with a lengthy iteration process,
this study used POM QM for Windows software to help solve research problems.
Data Description
Following is a description of the research data, which has been processed
and reduced from the raw data obtained from interviews and observations.
Table 1
Observation Data
NO |
NEED FOR |
SMALL PACKAGING |
MEDIUM PACKAGING |
LARGE PACKAGING |
|||
MANY UNITS = 600 |
MANY UNITS = 80 |
MANY UNITS = 250 |
|||||
VOLUME |
PRICE |
VOLUME |
PRICE |
VOLUME |
PRICE |
||
1 |
Soybeans |
36 kg |
306.000 |
3 kg |
25.500 |
45 kg |
382.500 |
2 |
Ragi Tempe |
4 ounces |
20.000 |
2 ounces |
4.000 |
5 ounces |
25.000 |
3 |
Cooking Oil |
36 L |
396.000 |
3 L |
33.000 |
45 L |
495.000 |
4 |
Flour |
36 kg |
288.000 |
3 kg |
24.000 |
45 kg |
360.000 |
5 |
Garlic |
8 ounces |
20.000 |
2 ounces |
4.000 |
1 kg |
25.000 |
6 |
Pecan |
4 ounces |
12.000 |
2 ounces |
6.000 |
5 ounces |
15.000 |
7 |
Salt |
4 ounces |
4.000 |
2 ounces |
2.000 |
4 ounces |
4.000 |
8 |
Seasonings |
5 gr |
5.000 |
4 gr |
4.000 |
5 gr |
5.000 |
9 |
Eggseggs |
12 |
12.000 |
0.5 kg |
12.000 |
15 eggs |
15.000 |
10 |
Coriander |
3 ounces |
6.000 |
2 ounces |
4.000 |
3 ounces |
6.000 |
10 |
WAGES |
250.000 |
100.000 |
250.000 |
|||
11 |
PACKAGING FEE |
200.000 |
90.000 |
200.000 |
|||
TOTAL |
Rp 1.519.000 |
Rp 308.500 |
Rp 1.782.500 |
||||
CAPITAL/UNIT |
Rp 2.550 |
Rp 3.900 |
Rp 7.150 |
||||
SELLING PRICE/UNIT |
Rp 5.000 |
Rp 6.500 |
Rp 12.500 |
||||
TOTAL TIME |
950 MINUTES |
729 MINUTES |
1.010 MINUTES |
Table 2
Description of Data Per Unit
of Production
No |
Type Packaging |
Many Units |
Total Cost |
Total Time |
Cost per Unit |
Selling price per Unit |
Time per Unit |
Total Selling |
Profit per unit |
1 |
Small |
600 |
1.519.000 |
950 |
2.550 |
5000 |
1,58 |
3.000.000 |
2.450 |
2 |
Medium |
80 |
308.500 |
729 |
3.900 |
6.500 |
9,11 |
520.000 |
2.600 |
3 |
Large |
250 |
1.782.500 |
1.010 |
7.150 |
12.500 |
4,04 |
3.125.000 |
5.350 |
TOTAL |
930 |
3.610.000 |
2.689 |
- |
- |
- |
6.645.000 |
- |
From
table 1, it can be calculated that the initial profit value = 6,645,000 �
3,610,000 = 3,035,000 rupiah.
Mathematical Modeling
The
mathematical model of this research problem is :
Determining
Total Production Units
:��
Total cost :
Total time �:
so that the values of
The
first simplex table, compiled by changing all the constraint functions in
implicit form, by adding a slack variable
The implicit form of the profit function:��������������������������������������������������
The first simplex table is:
Table 3
�Simplex First Table
Basis |
X1 |
X2 |
X3 |
S1 |
S2 |
S3 |
H |
S1 |
1 |
1 |
1 |
1 |
0 |
0 |
930 |
S2 |
2.550 |
3.900 |
7.150 |
0 |
1 |
0 |
3.610.000 |
S3 |
1,58 |
9,11 |
4,04 |
0 |
0 |
1 |
2.689 |
Z |
-2.450 |
-2.600 |
-5.350 |
0 |
0 |
0 |
0 |
Furthermore,
to analyze the research data used software POM QM for Windows. The input of
research problem data into POM QM is shown in the following table:
Table 4
Input Data
X1 |
X2 |
X3 |
RHS |
Equation form |
||
Maximize |
2450 |
2600 |
5350 |
Max 2450X1 + 2600X2 + 5350X3 |
||
Many units |
1 |
1 |
1 |
<= |
930 |
X1 + X2 + X3 <= 930 |
Production Cost/unit |
2550 |
3900 |
7150 |
<= |
3610000 |
2550X1 + 3900X2 + 7150X3 <= 3610000 |
Production Time/unit |
1,58 |
9,11 |
4,04 |
<= |
2689 |
1,58X1 + 9,11X2 + 4,04X3 <= 2689 |
Results of Data Analysis
The
results of data processing using POM-QM are shown in the following tables:
Table 5
Linear Programming Result
|
X1 |
X2 |
X3 |
� |
RHS |
Dual |
Maximize |
2450 |
2600 |
5350 |
|
|
|
Constraint 1 |
1 |
2600 |
1 |
<= |
930 |
842.39 |
Constraint 2 |
2550 |
3900 |
7150 |
<= |
3610000 |
.63 |
Constraint 3 |
1.58 |
9.11 |
4.04 |
<= |
2689 |
0 |
Solution |
660.76 |
0 |
269.24 |
|
3059294.0 |
|
Table 6
Solution List
Variable |
Status |
Value |
X1 |
Basic |
660.76 |
X2 |
NONBasic |
0 |
X3 |
Basic |
269.24 |
slack 1 |
NONBasic |
0 |
slack 2 |
NONBasic |
0 |
slack 3 |
Basic |
557.27 |
Optimal Value (Z) |
|
3059294.0 |
Table
7
Iteration
Cj |
Basic Variables |
Quantity |
2450 X1 |
2600 X2 |
5350 X3 |
0
slack 1 |
0
slack 2 |
0 slack 3 |
Iteration 1 |
|
|
|
|
|
|
|
|
0 |
slack 1 |
930 |
1 |
1 |
1 |
1 |
0 |
0 |
0 |
slack 2 |
3,610,000 |
2,550 |
3,900 |
7,150 |
0 |
1 |
0 |
0 |
slack 3 |
2,689 |
1.58 |
9.11 |
4.04 |
0 |
0 |
1 |
|
zj |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
|
cj-zj |
|
2,450 |
2,600 |
5,350 |
0 |
0 |
0 |
Iteration 2 |
|
|
|
|
|
|
|
|
0 |
slack 1 |
425.1049 |
0.6434 |
0.4545 |
0 |
1 |
-0.0001 |
0 |
5350 |
X3 |
504.8951 |
0.3566 |
0.5455 |
1 |
0 |
0.0001 |
0 |
0 |
slack 3 |
649.2238 |
0.1392 |
6.9064 |
0 |
0 |
-0.0006 |
1 |
|
zj |
2,701,188.75 |
1908.04 |
2918.18 |
5350 |
0 |
.75 |
0 |
|
cj-zj |
|
541.958 |
-318.1818 |
0 |
0 |
-0.7483 |
0 |
Iteration 3 |
|
|
|
|
|
|
|
|
2450 |
X1 |
660.7609 |
1 |
0.7065 |
0 |
1.5543 |
-0.0002 |
0 |
5350 |
X3 |
269.2391 |
0 |
0.2935 |
1 |
-0.5543 |
0.0002 |
0 |
0 |
slack 3 |
557.2717 |
0 |
6.808 |
0 |
�� -0.2163 |
-0.0005 |
1 |
|
zj |
3,059,293.5 |
2450 |
3301.09 |
5350 |
842.39 |
.63 |
0 |
|
cj-zj |
|
0 |
-701.087 |
0 |
� -842.3913 |
-0.6304 |
0 |
Interpretation of Data
Analysis Results
From the results of data analysis, several things
can be explained as follows:
Table 7. It is an iterative process from the initial
simplex table to obtain an optimal table that describes the optimal conditions
with variable values that have been obtained.
Table 6. illustrates the solution to the linear
programming problem, it can be seen that the maximum profit value per
production period that can be achieved is 3059294.0 rupiah, achieved at
conditions X1 = 660.76, X2 = 0 and X3 = 269.24. If Xrounded
up1 = 661 is, X2 = 0 and X3 = 269, this means that to obtain maximum profit,
the company must produce 661 units of small packaging and 269 units of large packaging,
with a maximum profit
of: Zmax = 2,450 (661)+2,600 (0)+5,350 (269) = 3,058,600, with production
costs :
Optimal Production Cost = 2,550(661) + 3,900(0) +
7,150(269) = 3,608,900 rupiah (there was a decrease in costs production of
3,610,000-3,608,900 = 1,100 rupiah). From Table 6. The value of the slack 3
variable is 557.27, this shows that if the optimal conditions are implemented,
the total time used is 557.27 minutes shorter than the previous total time. In
real terms, it can be shown that: Total optimal time = 1.58(661) + 9,11(0) + 4.04(269)
= 2.131.14 minutes. Time difference = 2.689 � 2.131.14=557.86 minutes (the
difference is due to the above rounding).
In summary, the efficiency obtained by the company,
after data analysis is presented in the following table:
Table 8
Efficiency of Research
Results
|
Initial Condition |
Final
Condition |
Efficiency |
Production |
600 units small pack �
80 medium pack 250 units big pack Number of units 930 |
661 units small pack 0 medium pack 269 units big pack Number of units 930 |
- |
Prod. Cost (Rp.) |
3.610.000 |
3.608.900 |
1.100 |
Time
(Minutes) |
2.689 |
2.131,14 |
557,86 |
Profit (Rp.) |
3.035.000 |
3.058.600 |
23.600 |
CONCLUSION
To be able to achieve a maximum profit of 3,058,600 rupiah, the company
must produce 661 units of small packaging and 269 large packaging and the
company gets an additional profit of 23,600 rupiah per production period,
Under optimal conditions, the total production cost becomes 3,608,900
rupiah, there is an efficiency (decrease) of 1,100 rupiah.
If the company runs production according to optimal conditions, the time
required is 557.86 minutes less than the production time before the study.
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