Decision Support System for Stock Investment on Mobile Device – Ivan Satria Dedi Trisnawarman
ISSN 1858-1633 2005 ICTS 87
2.3. Stock
Stock is valuable papers that used as an ownership proof of a company, usualy stock used as a media
for the commpany to gain more capital and expand their business.[4]
2.4. Prototyping
Engineer appliance is determination and using the engineer principal in order to get the trusted
application, economic, and work efficiently in computer. To engineer the software need a systematic
approach, this called prototyping.
The software design is a result of hardware development and system design. Prototyping method
gives strong basic control to the software development, to develop a high quality and controlled
software. The systematic steps of prototyping approach in software development are :
1. Data Gathering
Search and collecting data needs for creating, designing database and to identify problems.
2. Temporary design Create a blueprint of the design software to
gives images of the objects and the software format for input and output.
3. Prototype Building The temporary design is collected and arrange
into a computer language. 4. Prototype Evaluation
Makes evaluation on software output to identify if the result is suitable with the expected
outcome. This phase also conducted to all the function.
5. Product Making Is the last phased in prototyping method, where
the full software is created.
2.5. System Design
The Decision Support System for Stock Investment on Mobile Device designed in 2 parts,
first is the web application that used as the data gather and data store for the stock value, currency exchange
value, inflation rate value. The decision support mathematical models calculation also take place on
the web. The web application used to ensure the stock data used in the calculation is the latest data. The
second part of the application is the mobile device application side that used as an interface to
communicate to the web application.
2.6. Database Model
The database model used in designing the decision support system is E-R Diagram. E-R Diagram is a
model network that use arrangement data that save in the system in abstract. E-R Diagram describes the
relationship among entities in the integrated system. The relationship on basis data are: one to one
relationship, one to many relationship, and many to many relationship. In E-R Diagram, the entities
relationship resulted several tables. Those tables still not normal, because of all data in the table still
redundant. Therefore, normalization is needed in order to make those tables into normal and free from
data redundant.
The data used in the decision support system for stock investment on mobile device, is the stock
current value, the Indonesian currency rate, the inflation rate and the inflation rate that gathered from
the internet from Jakarta market quotes and Indonesian banks website. This data gathered and
stored automatically to the database using a php regular expression scripts. list and finds a song from
Corrs that she likes but does not have in her collection. Then she plays the song.
After a half an hour, together with other passengers, she is asked to board in. Immediately
after she leaves the waiting room, the new mp3 files are gone from the list.
2.7. Stock Valuation
The method use for stock valuation is portfolio model.
Portfolio model is a model that collect several stocks, and from that stocks which have been
collected will be use mathematics approach, in order to predict the future stock price. The usage of
portfolio method is to forcasting the sellected stocks. To evaluate stock valuation will be use several
methods. a. Simple Moving Average :
Simple Moving Average method is used to make prediction the next value based on previous stocks
value. This method is more common, because it is the simpliest method. Meanwhile the results are more
accurate for short term.
F
T + 1
=
∑
= T
i i
X T
1
1
1 F = Forecasted value.
X = Present Value. T = Time.
b. Exponential Moving Average : Exponential Moving Average method is one of
the most poppular and easy to to use. With combining the average of moving average value this methode
smooth the value on the chart to identify the trend. X = [ KxC-P]+P
2 X
= Exponential Moving Average
C = Current vale P = EMA Previous Period
K = Smoothing Constant K= 21+N
3 N = period of Exponenttial Moving Average
Information and Communication Technology Seminar, Vol. 1 No. 1, August 2005
ISSN 1858-1633 2005 ICTS 88
c. Inday Trading Inday Trading or known as one day trading, is a
trading method in a very short amount of time. In this method there’s some technic used, such as Pivot
Points. Pivot Points is a value points that used as an anchor to predeict the stock next value.
Pivot Point = high + Low + Close + Open4 Support-1 = 2Pivot-High
Support-2 = Pivot-High-Low Resistance-1 = 2Pivot-low
Resistance-2 = Pivot + High – Low
4 d. Sthocastic Oscillator
This method is created by George C. Lane, that used to locate the relatif closing value of a stock in a
period. The asumtion used in this method is the stock price usually closed near the highest price in bullish
trend.
K = 100 ⎟⎟
⎠ ⎞
⎜⎜ ⎝
⎛ −
− Re
n LowestLow
n h
HighestHig n
LowestLow centClose
5
n = number of period used e. William R
This indicator was develop by Larry William. R is one of the most poppular momentum indicator
to measure the stock over bought over sold value. The scale used in this indicator is from 0 to -100, with
the substance that from 0 to -20 is over bought and - 80 to -100 is over sold.
R= 100
− −
− periods
over Low
Lowest Periods
over high
Highest Close
Periods over
high Highest
6
Figure 1 Stock Selection on Mobile Application Interface
2.8. Hierarchy Analytical Process
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