My WPM

Honestly, I typed way faster when I was in high school playing games all day.
Here is my WPM by the way.

Lean Manufacturing / Improving facility

Okay... I have been trying to find an intern, part/full position during this summer for a company/facility to try my knowledge and skills in lean manufacturing and six sigmas learned at my school and previous works. Although I failed to do so, I am going to virtually share what I am going to do actually if I were to involved in actual project.

Since I was mainly hoping to work at a manufacturing facility, I will use simple manufacturing company as an example.

First, I would have to do some study and evaluate company's current situation. I have to gather data such as time, tasks assigned to each station, number of works, and all other necessary data.

Well, at this step, we need some theoretical standard numbers to compare those recorded data with to see if company is doing below or above the standard. These standards can be calculated using many different techniques such as

1. time study
2. motion study
3. queueing theory
4. assembly line balancing technique. 

If the company is doing below calculated standards, then management should step in and make some changes to maximize their utilization and reduce wastes.
To achieve this, company may need to redesign their facility more organized and efficient. They may also need to train their workers to do the job in proper way which maximizes their process. The most important thing is that the top management should be willing and able to make this changes even though it may cost them now.
At this step, company may incorporate such techniques as:

1. Facility redesign
2. Kaizen - gradual continuous improvement.
3. Poke-yoke - mostly done by organizing work stations and making somekind of signs.
4. PDCA/DMAIC - Plan Do Check Act/ Define Measure Analysis Improve Control. Both are for Six Sigma
5. Simulation(promodel) - to see if the theoretical changes actually improves the system (if used right, helps company save tons money)
6. 5s - Sort, Set in order, Shine, Standardize, Sustain

Once company made changes and improved their process, the most important thing is to sustain those changes by making check list. It would be nice thing to give rewards to department or people who made most improvements or suggested most realistic and helpful improvement to company to reinforce workers to be actively involved in improvement.

The Goal by Goldratt

I read this book mainly because it was assigned as assignment.
Its actually great book teaching you how to minimize the cost and optimize your process using TOC and other concepts. I had to write a book review on this book and here is what I wrote:

The goal by Eli M. Goldratt is a novel focused on Alex Rogo, who is a production manager of a company having hard time. Alex is introduced to a concept of TOC after meeting his old guru Jonah. The intention of theory of constraint, which Goldratt's most famous for, is to improve the system by identifying and eliminate the constraint that is holding back the company's performance hence increases their throughput. TOC states that, running areas with higher capacity will not increase throughput of system. Management should find are with lowest capacity, which is their bottleneck, and try to increase its capacity. Goldratt introduces 5 step models to achieve that. First, company should identify the constraints. Second, decide how to exploit constraints. Third, subordinate everything else to the above decision. Fourth, elevate the system's constraint. Lastly, if the constraint from first step is broken, go back to step 1. Throughout the novel, Goldratt tries to explain and prove the importance of TOC and his principles. In addition to these 5 steps, one should ask these three questions too. What to change? What to change it to? How to cause the change? These three questions should go along with the 5 step model when incorporating theory of constraints in business. Rogo believed that these three questions were essential to managers in order to successfully understand and apply theory of constraints. In the novel, Rogo was successful in fixing company's problem and promoted. These concepts and ideas are really relevant to any type of business and any professions. Because of the economy factors of nowadays, many companies are trying to minimize their costs and resources and I believe "The Goal" is the one of must read book that will help people to achieve it.

Decision making using decision tree analysis

Decision Tree
And
Analysis

PREPARED BY

Young Kim

IE417 Section 1 Spring 2013

REVISION PAGE:

REVISION        DATE                           DESCRIPTION

      N/C                        06-05-2013                  Initial Release

1.0  Introduction:

The following report demonstrates decision making analysis using decision tree.

2.0  PROBLEM

CEO of Cerebrosoft, Charlotte Rothstein, is faced with a situation where her company needs to make decision whether to launch the product or abandon it. When decided to launch it, they can go with a price of 3 categories, $50, $40, or $30. Once again, with $50 pricing range, they can choose either to hire researcher or not.

3.0  OBJECTIVE

To use technique of decision tree and probabilities to choose optimal scenario for Cerebrosoft with maximum expected revenue.

4.0  REFERENCE DOCUMENTS:

A. Operational Research Applications and Algorithms 4^th Edition, Wayne Winston
B. Lecture slide

5.0  REFERENCE SOFTWARE:

A.      Microsoft Excel

B.      Microsoft Word

6.0  ASSUMPTIONS & RATIONALE:

-          When abandoned, their initial investment of $800000 is lost

-          No marketing, including advertising, or annual support cost of $50000 is encountered in calculation of revenue.

7.0  Decision Tree and Probabilities

Below is embedded file of Decision Tree Diagram and Probabilities Calculation

(I actually have files 4 files embedded in this documents, but its not visible here, hence i will just post it here :))

Without Researcher

-

                         With Researcher

d

EVWPI(expected value with perfect information tree diagram)

Above is the probabilities




 Note: The expected value of node that contains multiple scenarios with probabilities in each tree diagram was calculated by multiplying previous expected value with the corresponding probability.

8.0  Findings

As you can see with the decision tree diagram without researcher, setting product price at $50 will give maximum expected revenue of $715,000 for the first year. If we take in account of support fee of $50,000, then our expected revenue of first year will be $665,000. From the following years, under the assumption that our probabilities stay same, we will have expected revenue of $1,465,000 since our initial investment of $800,000 is made up from first years revenue. The expected revenue from the following year will be

When it comes to decision of whether to hire researcher or not, our expected revenue from hiring researcher is determined to be $705,000.

EVSI is calculated by using equation EVSI = EVWSI – EVWOI which is ($705000+$10,000) - $715,000

EVSI is determined to be = $0.

EVPI is calculated by using equation EVPI = EVWPI – EVWOI

EVWPI is calculated by calculating expected maximum value for each state.
EVWPI = 0.2*$625,000 + 0.7*$725,000 + 0.1*$825,000
EVWPI is determined to be $715,000

EVWOI is calculated from calculation in EVSI which is determined to be $715,000
EVPI = $715,000 - $715,000 = $0

9.0  Conclusion

From the analysis, we can conclude that company should not hire a researcher and set the price of the product at $50 to have maximum expected revenue for first year of $715,000 before support investment of $50,000. This conclusion is drawn from the value of EVSI and EVPI. The minimum desired EVSI value is $10,000 which is the amount that company is willing to pay for the research. The EVSI calculated tells that the amount of research price that company is should pay to have extra expected value is $0, which means that as soon as price of research goes up, the expected profit of company drops by same amount. In other words, unless it is free to conduct the research, it is not worth doing it. The EVPI tells that the amount of money that company is willing to pay to know the trends is $0. Hence, in summary of this analysis, the company should not invest any money on extra information and set the price of product at $50 to maximize their expected profit.

Simple programming using visual basic

I have programmed this simple app to calculate what day of week is it using year, month, and day inputted by user.

I didn't know that first day of AD was MONDAY!!!! which implies, at least i think, is that jesus died on sunday because the last day of the BC was sunday 

Fault Tree Diagram

Its simple Fault Tree Diagram for

this fault tree diagram is not done... its more like prototype one.. I am going to extend it more with more technological terms and also add failure mode assessment & assignment matrices.

so here is what i have done so far 

Worst Case Tolerance and Statistical Tolerance Analysis and SPC

Embedded pictures are not showing here :( i'll post those graphs upon request if anyone want to see it.(its normal distribution with one side t-test using minitab)

Worst Case Tolerance

And

Statistical Tolerance

Analysis

PREPARED BY

Young Kim

REVISION PAGE:

REVISION        DATE                           DESCRIPTION

      N/C                        05-20-2013                  Initial Release

1.0  Introduction:

The following report demonstrates Worst Case Tolerance Analysis, WCTA, and Statistical Tolerance Analysis, STA .

2.0  PROBLEM

The part is failing due to clearance between circuit card from male part of assembly and a metal contacting device of female part of assembly.

3.0  OBJECTIVE

Using WCTA, STA, and statistical analysis to find suitable tolerance limit to eliminate or reduce probability of making parts outside of extreme tolerance zone.

4.0  REFERENCE DOCUMENTS:

A. Engineering drawing of part
B. Lecture slide

5.0  REFERENCE SOFTWARE:

A.      Microsoft Excel

B.      Microsoft Word

C.      Minitab 16

6.0  ASSEMBLY OVERVIEW:

The circuit card in male part of assembly which transmits the electrical current  is inserted between metal contacting device attached to female part of assembly to  provide power to main source.

7.0  ASSUMPTIONS:

For the calculation of STA, following assumptions were made

a. Parts are independent to each other

b. The tolerances are normally distributed

For the statistical analysis, following assumptions were made

a. The assembly tolerances are normally distributed
b. Standard deviation is Ti/3

8.0  DRAWING:

The following engineering drawing was used to identify necessary dimensions and its tolerances.

9.0  Data and Calculations

Dimension and Tolerance Data
Dimension Number	Dimension(d)	Ti
1A	0.87	0.1
1B	1.75	0.08
2A	1.94	0.12
2B	1.13	0.12
2C	0.4	0.1
Nominal Assembly Dimension Calculation
Bottom Contact Surface	Dimension Used	dn
Male	1B	1.75
Female	2A	1.94
Nominal Assembly  dimension (dnb)=  1.94-1.75 =    0.19
Top Contact Surface	Dimension Used	dn
Male	1A,1B	2.62
Female	2A,2C	2.34
Nominal Assembly  dimension(dnt )=  2.62 - 2.34 = 0.28
WORST CASE TOLERANCE ANALYSIS(WCTA)
Bottom Contact Surface
Dimension Used	Ti	Σ Ti	dnt	Max interference(dnt+Σ Ti)	Max Clearance(dnt-Σ Ti)
1B,2A	0.08, 0.12	0.2	0.19	0.39	-0.01
Top Contact Surface
Dimension Used	Ti	Σ Ti	dnb	Max interference(dnb+Σ Ti)	Max Clearance(dnt-Σ Ti)
1A,1B,2A,2C	0.08, 0.1, 0.12, 0.1	0.4	0.28	0.68	-0.12
Note: negative(-) sign indicates that there are clearance between male and female part when they are assembled
STATISTICAL TOLERANCE ANALYSIS(STA)
Bottom Contact Surface
Dimension Used	Ti	[ΣTi2](1/2)	dnt	Max Interference(dnt+[ΣTi2](1/2))	Min Interference(dnb-[ΣTi2](1/2))
1B, 2A	0.08, 0.12	0.144222051	0.19	0.334222051	0.045777949
Top Contact Surface
Dimension Used	Ti	[ΣTi2](1/2)	dnb	Max Interference(dnt+[ΣTi2](1/2))	Min Interference (dnb-[ΣTi2](1/2))
1A,1B,2A,2C	0.08, 0.1, 0.12, 0.1	0.201990099	0.28	0.481990099	0.078009901

10.0          STATISTICAL ANALYSIS

WCTA	Mean(Nominal)	Std(Ti/3)
Bottom Contact	0.19	0.06666667
	Mean(Nominal)	Std(Ti/3)
Top contact	0.28	0.13333333
STA	Mean(Nominal)	Std(Ti/3)
Bottom Contact	0.19	0.04807402
	Mean(Nominal)	Std(Ti/3)
Top Contact	0.28	0.06733003

11.0          EXPLANATION

We have a combined probability of 0.0027 of making parts with clearance on either top or bottom part of circuit card when using tolerances from WCTA. However, if we apply tolerance from STA, we have 0 probability of making parts with clearance, in other words, male and female parts produced will always have contact.

12.0          RECOMANDATION

The calculated nominal dimension interference for top and bottom part of circuit card is 0.19 and 0.28, respectively. Meaning that if we can reduce our worst case assembly tolerance to less than 0.19 for bottom circuit board assembly and less than 0.28 for top circuit board assembly, we will have 0 rejection rates. However, this is under the assumption that the production process is stable and capable of producing these parts within these specifications. Statistically, we have very low probability of making these parts out of our extreme tolerance zone.  The reason company is having such a high rejection rate, despite the low probability of producing parts out of specification, is because the production process might be either not stable or out of control or both. I would recommend, before we modify any design of this product, to monitor the production process to see if there are any assignable cause variation present. After confirming that the production process is stable and capable, and then I would recommend company to redesign the part with tighter tolerance to reduce the variation within the assembly. Although there could be many other modifications that can fix this problem, tightening the tolerance would cost least to fix the problem. One obvious solution to this problem is to tightening the tolerances.