• Title/Summary/Keyword: mathematics for economics

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An Analysis of Factors Impacting Vietnam's Coffee Exports: An Approach from the Gravity Model

  • PHUNG, Quang Duy;NGUYEN, Tai Cong
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.8
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    • pp.1-6
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    • 2022
  • This paper uses the gravity model estimated by the random effect method to analyze the factors affecting Vietnam's coffee export turnover for the period 2007-2020 major markets according to statistics from the General Statistics Office and the General Department of Customs. Coffee export turnover was collected from the General Statistics Office, General Department of Customs, and Vietnam Cacao Coffee Association. The authors calculated the price of coffee based on output and export value from data on coffee export turnover; the authors calculated the economic gap based on population and Gross Domestic Product data (reference: geographic distance metrics on the website: http://www.distancefromto.net/countries.php) and other data was collected based on the databases of the Food and Agriculture Organization of the United Nations, the International Monetary Fund, and World Bank organizations. The results of the study show that from 2007 to 2020, the factors of Vietnam's export price of coffee, geographical distance, Gross Domestic Product of the importing country and Gross Domestic Product of Vietnam, the population of Vietnam, the economic gap between Vietnam and the importing country, the openness of the economy, all have an impact on Vietnam's coffee export turnover. Finally, some conclusions about the policy's impact are made based on the empirical results of the paper.

An Integrated Ecological-Economic System Dynamics Model Analysis on the Ecosystem Restoration Policy (II): Extensions and Relaxations of the Model of King Crabs in the Imjin River, Korea (생태계 복원사업의 생태.경제 통합체계 동태분석(II) -임진강 참게 복원사업의 확장모형-)

  • Jeong, Hoi-Seong;Jeon, Dae-Uk
    • Korean System Dynamics Review
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    • v.7 no.2
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    • pp.97-120
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    • 2006
  • This paper deals with the extension of and discussion on the System Dynamics model (Jeong & Jeon, 2005) of river crabs in Korea. The previous model has been elaborated to empirically search for the optimal restoration and harvest rates of crabs in the Imjin River, on the basis of theoretical models of population dynamics in the field of bio-mathematics and environmental economics. In this paper, the authors tries to couple a series of new feedback loops related to density restrictions and cannibalistic behaviors with a stage-structured model of the crab ecosystem, and also to endogenize the parameter of baby crabs' survival that is caused by water quality improvement and income increase. Through these extensions and relaxations, the authors are able to argue about the strategic decision of the optimal rates additional considerations as well as the properties of the integrated system that was not covered in the previous paper.

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Reexamination of Estimating Beta Coecient as a Risk Measure in CAPM

  • Phuoc, Le Tan;Kim, Kee S.;Su, Yingcai
    • The Journal of Asian Finance, Economics and Business
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    • v.5 no.1
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    • pp.11-16
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    • 2018
  • This research examines the alternative ways of estimating the coefficient of non-diversifiable risk, namely beta coefficient, in Capital Asset Pricing Model (CAPM) introduced by Sharpe (1964) that is an essential element of assessing the value of diverse assets. The non-parametric methods used in this research are the robust Least Trimmed Square (LTS) and Maximum likelihood type of M-estimator (MM-estimator). The Jackknife, the resampling technique, is also employed to validate the results. According to finance literature and common practices, these coecients have often been estimated using Ordinary Least Square (LS) regression method and monthly return data set. The empirical results of this research pointed out that the robust Least Trimmed Square (LTS) and Maximum likelihood type of M-estimator (MM-estimator) performed much better than Ordinary Least Square (LS) in terms of eciency for large-cap stocks trading actively in the United States markets. Interestingly, the empirical results also showed that daily return data would give more accurate estimation than monthly return data in both Ordinary Least Square (LS) and robust Least Trimmed Square (LTS) and Maximum likelihood type of M-estimator (MM-estimator) regressions.

Optimum Risk-Adjusted Islamic Stock Portfolio Using the Quadratic Programming Model: An Empirical Study in Indonesia

  • MUSSAFI, Noor Saif Muhammad;ISMAIL, Zuhaimy
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.5
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    • pp.839-850
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    • 2021
  • Risk-adjusted return is believed to be one of the optimal parameters to determine an optimum portfolio. A risk-adjusted return is a calculation of the profit or potential profit from an investment that takes into account the degree of risk that must be accepted to achieve it. This paper presents a new procedure in portfolio selection and utilizes these results to optimize the risk level of risk-adjusted Islamic stock portfolios. It deals with the weekly close price of active issuers listed on Jakarta Islamic Index Indonesia for a certain time interval. Overall, this paper highlights portfolio selection, which includes determining the number of stocks, grouping the issuers via technical analysis, and selecting the best risk-adjusted return of portfolios. The nominated portfolio is modeled using Quadratic Programming (QP). The result of this study shows that the portfolio built using the lowest Value at Risk (VaR) outperforms the market proxy on a risk-adjusted basis of M-squared and was chosen as the best portfolio that can be optimized using QP with a minimum risk of 2.86%. The portfolio with the lowest beta, on the other hand, will produce a minimum risk that is nearly 60% lower than the optimal risk-adjusted return portfolio. The results of QP are well verified by a heuristic optimizer of fmincon.

Effects of Gratitude and Anticipation on Satisfaction: A Case Study in Indonesia

  • NOEGROHO, Gatoet Gembiro;SUHARYONO, Suharyono;SOLIMUN, Solimun;YULIANTO, Edy
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.2
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    • pp.1215-1224
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    • 2021
  • This research aims to discuss the relationship between the courage, anticipation, and satisfaction comprehensively. This study will be complemented by gratitude as a variable that moderates the relationship between courage and anticipation, as well as the relationship between the courage and satisfaction. The large area as survey location is the reason for sampling conducted in 2 stages: (1) taking 15 districts through judgement sampling, (2) allocated sub-districts sample through proportional random sampling. The sample used in this study were 155 sub-districts in East Java. Respondents in each sub-district consisted of 1 farmer and 1 field extension officer to get a total of 310 respondents. The analysis method used to test the hypothesis was Structural Equation Modeling (SEM). The findings of this research are: (1) The courage of field extension officers' have a positive but non-significant direct effect on farmers' anticipation, however, the effect significantly strengthen with religiosity as moderation; (2) The courage of field extension officers' and farmers' anticipation have a significant and positive effect on satisfaction. This study will be complemented by gratitude as a variable that moderates the relationship between the courage and anticipation, as well as the relationship between courage and satisfaction.

Analysis of Error Types in the Differential Problem Solving Progress (미분 문제해결 과정에서의 오류 분석)

  • Jun, Young-Bae;Roh, Eun-Hwan;Choi, Jung-Sook;Kim, Dae-Eui;Jeong, Eui-Chang;Jung, Chan-Sik;Kim, Chang-Su
    • Journal of the Korean School Mathematics Society
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    • v.12 no.4
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    • pp.545-562
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    • 2009
  • Calculus is used in various parts of human life and the basis of social science such as economics and public administration. Yet that is still considered important in the field of science and technology only, and there have been a lot of disputes on that phenomenon. Fortunately, calculus is going to be taught as part of the academic high school second-year mathematics curriculum in and after 2010. Students who face calculus for the first time should be helped not to lose interest in differentiation learning, not to be apprehensive of it nor to avoid it. The purpose of this study was to examine the types of errors made by students in the course of solving differentiation problems in an effort to lay the foundation for differentiation education. A pilot test was conducted after generalized differentiation problems to which students were usually exposed were selected, and experts were asked to review the pilot test. And then a finalized test was implemented to make an error analysis according to an error type analysis framework to serve the purpose.

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An Interdisciplinary Approach for the Solution of Enviromental polution (環境汚染의 解決을 위한 綜合科學的 接近方法 (I))

  • Sin, Hyeon-Deok
    • Journal of the Korean institute of surface engineering
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    • v.12 no.3
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    • pp.207-216
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    • 1979
  • Environmental pollution or contaminations caused by various kinds of pollutants have become one of most serious problems of our time. Environ mental pollution is the unfavoralble alteration of our surroundings, through direct or indirect effects of changes in energy patterns, rediation levels, chemical and physical constitution and abundances of organisms. These changes may affect humans directly or through their supplies of water and of agicultural and other biological products, their physical objects or possessions, or their opportunities for recreation and appreciation of nature. Pollutants that meet the criteria of this definition of environmental pollution are numerous: gases (such as sulfur dioxide and nitrogen oxides) and paniculate matter (such as smoke particles, lead aerosols, and asbestos) in the atmosphere; pesticides and radioactive isotopes in the atmosphee and in waterways; sewage, organic. chemicals, and phosphates in water; solid wastes on land; excessive heating (thermal pollution) of rivers and lakes; and many others. Some of these pollutants are introduced into the environment naturally, others by human actions, and most in both ways. Our major concer is with environmental pollution resulting wholly or largely as a by-product of human activities, because these can be controlled most readily. Environmental pollution cannot be solved by science and technology alone. It should be handled by an interdisciplinary approach with combined methods of science and technology as wen as social science disciplines for the better solution of this critical problem. In this respect, introducing "Environmental Science," a new scientific approach for the solution of environmental problems, which is now widely accepted by most developed countries of the world will be very helpful for systematization of theoretical basis for a new scientific approach to environmental pollution. Environmental science is "the study of all systems of air, land, water, energy, and life that surround Man. It includes all sciences directed to the system-level of understanding of the environment, drawing especially upon such disciplines as meteorology, geophysics, oceanography, and ecology, and utilizing to the fullest knowledge and techniques developed in such fields as physics, chemistry, biology, mathematics and engineering as well as many social science disciplines, such as economics, such as economics, law, political science and public administration." The components of this discipline are not new, for they are drawn from existing areas of science within biology chemistry, physics, and geoscience. What is really new about environmental science, however, is it siewpoint - its orientation to global problems, its conception of the earth as a set of interlocking, interacting systems, and its interest in Man as a part of these systems.

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Damage and Socio-Economic Impact of Volcanic Ash (화산재 양에 따른 피해와 사회 · 경제적 영향 분석)

  • Jiang, Zhuhua;Yu, Soonyoung;Yoon, Seong-Min;Choi, Ki-Hong
    • Journal of the Korean earth science society
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    • v.34 no.6
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    • pp.536-549
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    • 2013
  • This study investigates the damages of and analyzes the social and economic impacts of volcanic ash eruptions in the world in order to estimate the potential volcanic ash impacts in South Korea when Mt. Baekdusan volcano erupts in the future. First, we build a comparison chart called "the impact of volcanic ash" on each economic and social sector by using major volcanic eruptions and we compare the damage with respect to volcanic ash thickness/weights. Secondly, we analyze the social and economic impact from volcanic ash. The economic damage is not likely to occur in South Korea, unless Mt. Baekdusan erupts in winter. However, the potential damage should not be overlooked because the volcanic ash may have a global impact around the world. If Mt. Baekdusan volcano erupts when the wind blows from north or northeast, the volcanic ash may then significantly affect South Korea of which economy is highly dependent on exports. Particularly when the volcanic ash moves to the densely populated metropolitan areas or agricultural areas, the damage can be significant. In preparation for the potential volcanic disasters, the volcanic ash forecast table suitable for South Korea should be prepared. In addition, building a Korean volcanic ash hazard map in advance will have a strategic significance.

Site Suitability Analysis for Riverbank Filtration Using Game Theory (게임이론을 활용한 강변여과 개발 적지선정)

  • Lee, Sang-Il;Lee, Sang-Sin
    • Journal of Korea Water Resources Association
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    • v.43 no.1
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    • pp.95-104
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    • 2010
  • The tap water supply in Korea mainly depends on the surface water. However, the advanced water purification process becomes a necessity due to the deterioration of surface water quality and the risk of accidental spill. High cost of water treatment and public concerns make the decision makers turn to riverbank filtration as an alternative to the surface water. Riverbank filtration has been employed for water supply in many developed countries for more than 150 years. In Korea, riverbank filtration has drawn attention since 1990s as a supply source having potential to stably meet the ever-increasing water demand. Some cities located in the Nakdong River Basin are currently supplying water through riverbank filtration. This work studies the site suitability analysis for riverbank filtration using game theory. Theory of games, which is a branch of applied mathematics used in social sciences (most notably economics), biology, engineering and computer science, was applied to candidate locations for the selection of riverbank filtration site. We proposed a policy game model as a new method adopting a probabilistic approach. The model developed turned out to be an effective tool for site selection.

Effects of Constructivism-Based Teacher Education Program for Supporting Infant's Mathematical Inquiry Activity on Variables Related to Infant Teacher's Mathematics Teaching (영아 수학적 탐색활동 지원을 위한 구성주의 교사교육프로그램이 영아교사의 수학지도 관련 변인에 미치는 효과)

  • Ko, Eunji;Kim, Jihyun
    • Human Ecology Research
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    • v.58 no.1
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    • pp.105-120
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    • 2020
  • This study helps infant teachers practice a constructivism-based teacher education program that supports infant mathematical inquiry activities and examines improvements in mathematical teaching knowledge, mathematical teaching initiatives, mathematical interaction, constructivism belief and mathematical teaching efficacy. Twenty two experiment group infant teachers and twenty two comparison group infant teachers were chosen at two workforce educare centers. The experiment group infant teachers participated in 18 sessions of a constructivism teacher training program for 8 weeks, but the comparison group infant teachers did not take part in the program. Pretest and post-tests were implemented for the mathematical teaching knowledge, mathematical teaching initiatives, mathematical interactions, constructivism belief and mathematical teaching efficacy in the experiment group. Independent sample t-test and ANCOVA were tested using Windows SPSS statistics 21.0. The homogeneity test for the experiment and comparison group revealed significant differences. ANCOVA was carried out after the pretest score was controlled as a co-variance. Significant differences were indicated in mathematical teaching knowledge, mathematical teaching initiative, mathematical interaction, constructivism belief and mathematical teaching efficacy. The results indicated that a constructivism-based teacher education program to support infant mathematical inquiry activities influenced improvements in mathematical teaching knowledge, mathematical teaching initiative, mathematical interaction, constructivism belief and mathematical teaching efficacy. This study proved the effects of the program based on constructivism theory content for the knowledge, skills and attitude about infant teaching of mathematical initiatives and practiced a program of exploration, investigation, application and assessment for infant teachers. The results can help infant teachers teach mathematical exploration activities and help activate infant mathematical exploration activities.