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2018美赛O奖论文B题-B79002-How many languages-解密.pdf
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For office use only
T1
T2
T3
T4
Team Control Number
79002
Problem Chosen
B
For office use only
F1
F2
F3
F4
2018
MCM/ICM
How many languages?
To predict the number of the one language, we assume that native speakers are related to natural growth rate of its native
speaker and number of the its second speakers. Based on the data we collected, we use
time series languages speakers
difference equation model
to describe the dynamic change of both native and second language speakers, considering the
influence of foreign language taught in school, social media, economics, cultural communication and so on.
The difference equation model can apply our collected indicators to the prediction of change of language distribution over
time. 50 years later, top 10 languages in order of total speakers change from [Mandarin, English, Hindustani, Spanish, Arabic,
Malay, Russian, Bengali, Portuguese French] to [Mandarin ,English, Spanish, Hindustani, Arabic, Bengali, Portuguese, Malay,
Russian, French]; the rank of top 10 native languages speakers changes from [Mandarin, Spanish, English, Hindustani, Arabic,
Bengali, Portuguese, Russian, Punjabi, Japanese] to [Mandarin, Spanish, English, Hindustani, Arabic, Bengali, Portuguese,
Punjabi, Russian and Hausa]. By analyzing these changes, we find some reasonable explanations, such as the rapid natural
growth rate of some developing countries and some languages’ increasing speaking-power.
Given the global population growth and migration pattern, we establish
geographical distribution of difference equation
model, to predict the geographical distribution of different languages. Through the establishment of the difference equation,
we consider the relationship between the distribution of languages on different continents and main migration routes. We use
MATLAB to calculate language proportion changes on each continent over the next 50 years, finding some reasonable
predictions. For example, Mandarin will become the No.2 native language in North America and Australia. The proportion
of Mandarin and Arabic speakers in Europe will increase significantly.
In Part II, based on the requirement and the feature of service company, we choose six suitable cities based on our prediction
of language speakers. Also, we find that the cities are different depending on whether the company is long-term oriented (6
suggested cities: Shanghai, New York, Calcutta, Madrid, Dubai, and Rio de Janeiro) or short-term oriented (6 cities: Shanghai,
New York, Calcutta, Madrid, Dubai, and Singapore).
Moreover, we build the
cost-benefit analysis model
to calculate the suitable number of offices that this company should
build. Given the level of company’s profitability and cost, we set a new parameter, cost-profitability ratio. If the value of c-
p ratio is less than 281, we think 6 offices should be built. If the value of this ratio is between 281 and 422, we think 5 offices
should be built. If the value is between 422-527, 4 offices are best; if it is between 527 and 544, 3 office should be built; if>
544, we should only maintain two offices.
Finally, we analyze the performance of our model and the sensitivity of our model, proving that our model is relatively stable
for different parameters.
Key words: Language distribution, Time Series Difference Equation Model, Dynamic simulation, site selection
Cost-profit analysis
Team # 79002
Page 1 of 29
CONTENT
1 Introduction................................................................................................................................................. 2
1.1
Problem Background.................................................................................................................... 2
1.2
Our work.......................................................................................................................................2
2 Assumptions and Symbols.......................................................................................................................... 2
2.1
Assumptions of the initial data..................................................................................................... 2
2.2
Symbols and definitions............................................................................................................... 3
3 Part I Models and Results...........................................................................................................................4
3.1
Model I: Various Languages Speakers Difference Equation Model............................................4
3.1.1 The increase of the native speakers................................................................................................4
3.1.2 The increase of the second language speakers............................................................................... 5
3.1.3 The total difference equation of model I........................................................................................8
3.2
Model I Results & Analysis......................................................................................................... 8
3.2.1 Initial rank and parameter setting...................................................................................................8
3.2.2 Results & Analysis......................................................................................................................... 9
3.3
Model II: Geographical Distribution Difference Model............................................................ 10
3.4
Population growth fitting and current migration pattern............................................................11
3.5
The increase speakers of each language on each continent........................................................12
3.6
Result and Analysis.................................................................................................................... 13
4 Part II Models & Results.......................................................................................................................... 15
4.1
Assumptions about the service company................................................................................... 15
4.2
Explanation about our choices................................................................................................... 15
5 Sensitivity Analysis....................................................................................................................................17
5.1
sensitivity analysis of Model I....................................................................................................17
5.2
sensitivity analysis of model II...................................................................................................19
6 Strength and Weakness.............................................................................................................................20
7 Memo.......................................................................................................................................................... 21
8 Appendix.................................................................................................................................................... 22
8.1
data............................................................................................................................................. 22
8.2
program...................................................................................................................................... 24
Team # 79002
Page 2 of 29
1
Introduction
1.1 Problem Background
In the world of globalization, number of native speakers and L2 speakers of a certain language increase or
decrease over time. There are many factors that affect the increase or decrease of a certain language, including
the foreign language taught in school, cultural communication and assimilation, Economic Factor, technology,
social media and so on.
Our first task is to establish a model of the distribution of various language speakers over time, in which we
should consider the factor listed above.
Besides, our second task is the establish a model to predict the geographic distributions of these languages over
time based on the given globe population and human migration patterns for the next 50 years.
In the part II, a large multinational service company hire our team to give location options for new offices. So
our third task is to consider where we should locate these offices and if opening less than six offices better.
1.2 Our work
Language is such an important topic due to its role in cultural communication, international business, migration
issue and so on. Under the circumstance that we are consulted to give out 6 most suitable sites to build new
office by a service company, our main work is as follows:
Firstly, based on the data we collected, we use time series languages speakers difference equation model to
describe the dynamic change of both native and second language speakers, considering the influence of foreign
language taught in school, social media, economics, cultural communication and so on.
Secondly, considering the global population growth model and migration patterns, we establish geographical
distribution difference model, presenting the change of languages’ distribution in 6 main continents over 50
years.
Thirdly, we choose the six suitable cities based on our prediction of language speakers. Also, we find that the
cities are different depending on whether the company is long-term oriented or short-term oriented.
Moreover, we build the cost-benefit analysis model to calculate the suitable number of offices that this company
should build.
Finally, we analyze the performance of our model and the sensitivity of our model.
2
Assumptions and Symbols
2.1
Assumptions of the initial data
1. Those languages whose current total speakers are less than 100 million won’t become the top 10
languages. Thus, according to the list of languages by total number of speakers, we only use the data of
top 16 languages, since they are the only languages that are used by more than 100 million people.[1]
Reason: The French ranked 10th in 2017 with a total number of 228million speakers. According to common
sense, total number of Language speakers have a small possibility to decrease. So, those languages with fewer
than 100million speakers are less likely to become Top10 in 50 years. At the same time, we also do this to reduce
our computational load and to reduce our programming difficulty.
2. For some Languages L2 speakers number ‘?’in the [1], we assume it is zero.
Team # 79002
Page 3 of 29
Reason
: We speculate there may be two reasons for the coming of ‘?’. One is because the data is too small, not
good statistics. The other reason is that it is controversial to define who can be the second foreign language
speakers. For both reasons, we can all assume the number is zero.
3. We think native speaker's growth is only related to its own natural growth rate and second language
population
Reason:
According to our common sense, the growth of native speakers is often associated with changes in the
local population. Local population grow, native speakers also will grow. Foreigners migrate in, and the foreign
language native speakers increase. Therefore, native speaker changes and population changes are very relevant.
And in order to simply our model, we think native speaker's growth is only related to its own natural growth
rate and second language population.
[2]
4.We think L2 speaker’s growth is only affected by its own feature (the languages learned in school,
cultural communication) and the global situation (economics, development of technology, media use).
And the relationship between them is directly proportional.
Reason:
According to common sense, these factors positively affects the L2 speaker’s growth. Although we are
not quite sure whether the relationship between them is linear or not, in order to simplify the problem, we may
think that the relationship between them is linear, and therefore, proportional.
2.2 Symbols and definitions
Table 2 codes for top 16 languages
i
1
2
3
4
5
6
7
8
Language
s
Mandarin
English
Hindustani
Spanish
Arabic
Malay
Russian
Bengali
i
9
10
11
12
13
14
15
16
Languages
Portuguese
French
Hausa
Punjabi
German
Japanese
Persian
Swahili
Team # 79002
Page 4 of 29
3
Part I Models and Results
3.1 Model I: Various Languages Speakers Difference Equation Model
How to quantify the relationship between language growth and the various factors is a difficult problem? There
are a variety of time series models we could use. If we have enough data, we can regress the functional
relationship between the number of languages on various factors. But the truth is, we can’t find enough credible
data online. There are two reasons for this. One is because it is vague to judge whether a person has a second
foreign language ability. For this reason, different data sources may not come from the same criterion. So the
data between the two will be very different. In addition, the two data whose sources are the same, while years
are different are still not credible. This is because the dates of the censuses vary from country to country. This
makes a lot of data does not have time continuity. For these two reasons, we can’t and will not use those methods
of fitting forecasts.
Difference equation model can consider the impact of different factors on the size of the independent variables.
Moreover, the difference equation model only requires the initial data on it. These two characteristics fit very
well with our problem. The time step in which we set in the difference equation is one year. We denote that the
number of native speakers of language i in next period depends on the current number of its native speakers and
the current number of its 2
nd
language speakers. Therefore, we can construct a difference equation model to
describe the change of 2 types speakers for the 16 languages.
3.1.1 The increase of the native speakers
According to our common sense, the growth of native speakers is often associated with changes in the local
population. Local population grow, and native speakers also will grow. Foreigners migrate in, and the foreign
language native speakers increase. Therefore, native speaker changes and population changes are very relevant.
So, we assume that native speaker's growth is only related to its natural growth and the number of second
language speakers. We choose the weighted average of natural growth rate of countries whose official language
is the
language i
as the increase of the native speakers of language
i.
However, the world population growth pattern varies from countries. The most significant difference is the
difference between the population growth patterns in developing and developed countries. Therefore, we divide
these languages into two group. One type is mainly spoken in developed countries, and the other is mainly
spoken in the developing countries. Developed countries usually have low natural population growth rates and
high immigration rate while developing countries usually have higher natural population growth rates. To take
this difference into consideration, we divide all 16 languages into 2 types, according to their main speakers’
types—developed or developing.
Table 3 types of languages
types
languages
Type I: most spoken in developed countries
English, Spanish, French, German, Japanese,
Mandarin
Type II: most spoken in developing countries
Hindustani, Arabic, Malay, Portuguese, Hausa,
Punjabi, Persian, Swahili
Type I languages’ speakers’ growth model: Malthusian growth model
Type I languages are mainly spoken in developed countries, whose population usually have a very low natural
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