scholarly journals A system dynamics approach to balancing wood supply and demand for sustaining the future industry

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Yasuhiro Morii ◽  
Seiichi Furuta ◽  
Tomoki Ishikawa ◽  
Kensuke Fujiwara ◽  
Hiroko Yamashina ◽  
...  

Abstract Background Pharmacists play an important role in promoting people’s health in Japan, which has an aging population. Hence, it is necessary that the distribution of pharmacists meets the population’s needs in each region. This study projects the future supply and demand for pharmacists in pharmacies to consider an optimal distribution of pharmacists. Methods The future supply of pharmacists working in pharmacies in Hokkaido is projected using system dynamics modeling, according to their career path. The demand is projected based on the number of prescriptions, sourced from publicly available sources. The analysis period is 2015–2040. The estimated demand is converted into the number of pharmacists and the sufficiency is evaluated using sufficiency ratio (supply/demand ratio). Sensitivity analyses of the sufficiency ratio were conducted to estimate the effects of changes in parameters such as national exam pass rate, enrollments, attrition rates, the number of prescriptions per pharmacist, and diffusion of newly licensed pharmacists. Results The projected supply, in 2025 and 2040, is 1.24 and 1.56 times, respectively, as that in 2015 and the demand is 1.11 and 0.98 times, respectively. In 2015, although the sufficiency ratio in Hokkaido overall is 1.19, the ratios are higher in urban medical areas and lower than 1 in rural medical areas, such as Minamihiyama, Emmon, and Nemuro. By 2040, the sufficiency ratios are greater than 1 for all areas except for Emmon and higher than 2 in some areas. The sensitivity analyses found that the sufficiency ratio was most sensitive to diffusion of newly licensed pharmacists and the number of prescriptions per pharmacist. Conclusion Optimal distribution should be considered, as the results reveal a possible shortage in the number of pharmacists in rural medical areas in 2015–2025. Conversely, as the demand is projected to decrease after 2025 with a population decrease, future supply should be determined in order not to cause an oversupply after 2025. Refinements of the projection model should be conducted since the related factors such as the roles of pharmacists will change over time.


Author(s):  
Hunter M. Holzhauer

This chapter begins with a breakdown of recent growth trends for the overall commodities market. However, the long-term future of the market will heavily depend on three pressing issues: excess supply, increased regulations, and algorithmic trading. The section on excess supply explores how traders are changing strategies to adjust to the current imbalance between supply and demand, especially in the steel industry, and how that imbalance might change in the future based on global population trends and climate change concerns. The next section examines several regulatory trends, including the dramatic exodus of some investment banks from certain segments of the commodities market followed by a section focusing on how algorithmic trading is influencing how commodities are traded. A discussion of potential scenarios for the commodities market follows. The chapter concludes by examining a few ways in which the market and commodity traders may both survive and even thrive in the future.


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4581
Author(s):  
Yuko Hirase ◽  
Yuki Ohara ◽  
Naoya Matsuura ◽  
Takeaki Yamazaki

In the field of microgrids (MGs), steady-state power imbalances and frequency/voltage fluctuations in the transient state have been gaining prominence owing to the advancing distributed energy resources (DERs) connected to MGs via grid-connected inverters. Because a stable, safe power supply and demand must be maintained, accurate analyses of power system dynamics are crucial. However, the natural frequency components present in the dynamics make analyses complex. The nonlinearity and confidentiality of grid-connected inverters also hinder controllability. The MG considered in this study consisted of a synchronous generator (the main power source) and multiple grid-connected inverters with storage batteries and virtual synchronous generator (VSG) control. Although smart inverter controls such as VSG contribute to system stabilization, they induce system nonlinearity. Therefore, Koopman mode decomposition (KMD) was utilized in this study for consideration as a future method of data-driven analysis of the measured frequencies and voltages, and a frequency response analysis of the power system dynamics was performed. The Koopman operator is a linear operator on an infinite dimensional space, whereas the original dynamics is a nonlinear map on a finite state space. In other words, the proposed method can precisely analyze all the dynamics of the power system, which involve the complex nonlinearities caused by VSGs.


2021 ◽  
pp. 315-335
Author(s):  
Edward W. Fuller

Every investment project is aimed at achieving some future goal. This goal can only be attained by employing scarce resources, like time. Every investment project entails foregoing other investment projects. It is impossible to undertake all investment projects simultaneously because resources are scarce. This means each investment project is subject to cost. The investment project may be unsuccessful in achieving the future goal and the entrepreneur may suffer a loss. On the other hand, investment projects are only undertaken because they are perceived as more valuable than their costs. Every investment project undertaken implies the possibility of earning a profit. Investment projects take time. An investment project can be represented by a time line. Time A represents the beginning of the production process. Time B is the end of the production pro-cess. Line AB is called the period of production. Present goods are scarce resources that can be consumed im-mediately. On the other hand, future goods cannot be consumed immediately. Future goods are only expected to be consumer goods at some point in the future. An investment project entails making an investment at time A and receiving a present good at time B. All else equal, present goods are more valuable than future goods.1 Any good at time A is more valuable than the same good at time B. This is called time preference. Money is the present good par excellence. Therefore, future goods can be called future cash flows. All else equal, present money is more valuable than future money. This is called the time value of money. The interest rate is the price of present goods in terms of future goods. The interest rate is the price which equates the amount of present goods provided by savers with the amount of present goods demanded by investors. Like all prices, the interest rate is determined by supply and demand. Savers are suppliers of present goods. The supply curve (S) is the quantity of present goods supplied at each interest rate. Factor owners (investors) are the demanders, or buyers, of present goods. The demand curve (D) is the quantity of present goods demanded at each interest rate. The intersection of the supply and demand curve determines the interest rate. The interest rate is determined by the supply and demand for present goods:2


Memorias ◽  
2018 ◽  
pp. 58-66
Author(s):  
Johnny Valencia ◽  
Gerard Olivar ◽  
Johan Manuel Redondo ◽  
Danny Ibarra Vega ◽  
Carlos Peña Rincón

In this paper, we show the preliminary results in a proposed a model for the supply and demand of electricity in a domestic market based on system dynamics. Additionally, the model indicates piecewise smooth differential equations arising from the diagram of flows and levels, using dynamical systems theory for the study of the stability of the equilibrium points that have such a system. A bifurcation analysis approach is proposed to define and understand the complex behavior. Until now, no work has been reported related to this topic using bifurcations criteria. The growing interest in personal ways of self-generation using renewable sources can lead the national grid to a standstill and low investment in the system. However, it is essential to preserve the national network as a power supply support to domestic and enterprise demand. To understand this scenario, we include an analysis of zero-rate demand growth. Under this hypothesis, a none smooth bifurcation appears related to a policy which involves the variation of the capacity charge. As a first significant result, we found that it is possible to preserve the investments in the market since, through the capacity charge parameter, the system dynamics can be controlled. Then, from a business approach, it is necessary to know the effects of the capacity charge as the strategic policy in the system generation price scheme.


2021 ◽  
Vol 28 (1) ◽  
pp. 101-116
Author(s):  
Fang Chen ◽  
Xi Chen ◽  
Xinjian Zhang

Abstract With the rapid growth of flight volume, the contradiction between insufficient support capability of air traffic control (ATC) units and large demand for development ultimately hinders their sustainable and safe development. The article aims at the leverage point of the contradiction between supply and demand so as to provide scientific safety policies. Based on the system archetype “growth and underinvestment”, from the perspective of the feedback relationships between support capability, safety, and development, the causality of the dynamic factors of control, communication, navigation, and surveillance, as well as meteorology and information subsystems was studied. Then, a system dynamics model for the sustainable and safe development of ATC units was established. Taking the Tianjin ATC sub-bureau as an example, policy suggestions for sustainable and safe development were put forward according to the scenario simulation results.


Sign in / Sign up

Export Citation Format

Share Document