Transportation and regional agglomeration in Japan: Through a long-term simulation model 1920-85

1995 ◽  
Vol 29 (2) ◽  
pp. 213-233 ◽  
Author(s):  
Sihil Daluwatte ◽  
Asao Ando
Keyword(s):  
Simulation Model

Effects of Future Demographic Changes on the US Economy: Evidence from a Long-term Simulation Model

1998 ◽  
Vol 10 (3) ◽  
pp. 239-262 ◽  
Author(s):  
Tim A. Dowd ◽  
Ralph M. Monaco ◽  
Jeffry J. Janoska
Keyword(s):  
Simulation Model ◽  
Demographic Changes ◽  
Us Economy ◽  
The Us

Manipulation of fishing effort in Australia's penaeid Prawn Fisheries

1990 ◽  
Vol 41 (1) ◽  
pp. 1 ◽  
Author(s):  
IF Somers
Keyword(s):  
Side Effects ◽  
Great Barrier Reef ◽  
Simulation Model ◽  
Fishing Effort ◽  
Regulatory Mechanisms ◽  
Barrier Reef ◽  
Restrictive Measures ◽  
The Impact ◽  
Term Management

The potentially detrimental side-effects of prawn trawling are coming under increasing scrutiny in Australian waters, particularly in such ecologically sensitive areas as Queensland's Great Barrier Reef, and various restrictive measures are being suggested. Before changes are imposed on the prawning industry, the effects of trawling on the target prawn species and the long-term management of these effects need to be fully understood. Using a simulation model of a simplified prawn fishery, this paper describes the basis for the current regulatory mechanisms for Australian's prawn fisheries, in particular the manipulation of both the level and pattern of fishing effort. It is shown that even in moderately fished stocks, the fishery manager has several options, such as seasonal and nursery area closures, that are consistent with the goal of minimizing the impact of prawn trawling, while in no way penalizing the industry economically. With these in mind, possible ways of resolving or reducing the conflict with groups outside the prawning industry are discussed.

Comparison Between DEXA and Finite Element Studies in the Long-Term Bone Remodeling of an Anatomical Femoral Stem

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
A. Herrera ◽  
J. J. Panisello ◽  
E. Ibarz ◽  
J. Cegoñino ◽  
J. A. Puértolas ◽  
...  
Keyword(s):  
Finite Element ◽  
Bone Density ◽  
Bone Mass ◽  
Simulation Model ◽  
Load Transfer ◽  
Fe Simulation ◽  
Femoral Stem ◽  
Mineral Density ◽  
Biomechanical Behavior

The implantation of a cemented or cementless femoral stem changes the physiological load transfer on the femur producing an effect on the bone called adaptative remodeling. The patterns of this remodeling are attributed to mechanical and biological factors, and those changes in bone mineral density have been determined in long-term densitometry studies. This technique has proved to be a useful tool able to quantify small changes in bone density in different femoral areas, and it is considered to be ideal for long-term studies. On the other hand, the finite element (FE) simulation allows the study of the biomechanical changes produced in the femur after the implantation of a femoral stem. The aim of this study was to contrast the findings obtained from a 5 year follow-up densitometry study that used a newly designed femoral stem (73 patients were included in this study), with the results obtained using a finite element simulation that reproduces the pattern of load transfer that this stem causes on the femur. In this study we have obtained a good comparison between the results of stress of FE simulation and the bone mass values of the densitometry study establishing a ratio between the increases in stress (%) versus the increases in bone density (%). Hence, the changes in bone density in the long term, compared with the healthy femur, are due to different load transfers after stem implantation. It has been checked that in the Gruen zone 7 at 5 years, the most important reduction in stress (7.85%) is produced, which coincides with the highest loss of bone mass (23.89%). Furthermore, the simulation model can be used with different stems with several load conditions and at different time periods to carry out the study of biomechanical behavior in the interaction between the stem and the femur, explaining the evolution of bone density in accordance to Wolff’s law, which validates the simulation model.

A Generic Simulation Model of the Relative Cost-Effectiveness of ICU Versus Step-Down (IMCU) Expansion

2017 ◽  
Vol 35 (2) ◽  
pp. 191-202
Author(s):  
Amin Mahmoudian-Dehkordi ◽  
Somayeh Sadat
Keyword(s):  
Intensive Care ◽  
Cost Effectiveness ◽  
Simulation Model ◽  
Cost Effective ◽  
Capacity Expansion ◽  
Baseline Scenario ◽  
Relative Cost ◽  
Relative Cost Effectiveness ◽  
Step Down

Background: Many jurisdictions are facing increased demand for intensive care. There are two long-term investment options: intensive care unit (ICU) versus step-down or intermediate care unit (IMCU) capacity expansion. Relative cost-effectiveness of the two investment strategies with regard to patient lives saved has not been studied to date. Methods: We expand a generic system dynamics simulation model of emergency patient flow in a typical hospital, populated with empirical evidence found in the medical and hospital administration literature, to estimate the long-term effects of expanding ICU versus IMCU beds on patient lives saved under a common assumption of 2.1% annual increase in hospital arrivals. Two alternative policies of expanding ICU by two beds versus introducing a two-bed IMCU are compared over a ten-year simulation period. Russel equation is used to calculate total cost of patients’ hospitalization. Using two possible values for the ratio of ICU to IMCU cost per inpatient day and four possible values for the percentage of patients transferred from ICU to IMCU found in the literature, nine scenarios are compared against the baseline scenario of no capacity expansion. Results: Expanding ICU capacity by two beds is demonstrated as the most cost-effective scenario with an incremental cost-effectiveness ratio of 3684 (US $) per life saved against the baseline scenario. Sensitivity analyses on the mortality rate of patients in IMCU, direct transfer of IMCU-destined patients to the ward upon completing required IMCU length of stay in the ICU, admission of IMCU patient to ICU, adding two ward beds, and changes in hospital size do not change the superiority of ICU expansion over other scenarios. Conclusions: In terms of operational costs, ICU beds are more cost effective for saving patients than IMCU beds. However, capital costs of setting up ICU versus IMCU beds should be considered for a complete economic analysis.

Industry drug development portfolio forecasting: productivity, risk, innovation, sustainability

2020 ◽  
Vol 25 (2) ◽  
Author(s):  
Vladimir Shnaydman
Keyword(s):  
Drug Development ◽  
Simulation Model ◽  
Cycle Time ◽  
Empirical Formulas ◽  
Current Trends ◽  
Fda Approval ◽  
Industry Performance ◽  
Economic Trends ◽  
Demographic Shifts

Multiple factors may affect industry performance, risk, innovation and sustainability in coming years such as long-term economic trends, patents expiration, demographic shifts, and regulatory issues.   Currently available industry-wide prediction frameworks have limited capabilities. They are based on: (1) analysts’ consensus; (2) extrapolation of current trends; (3) financial performance of big pharma only; (4) empirical formulas, etc. Therefore, the need of robust forecasting methodology based on simulation modeling and covering the entire industry portfolio predictions could not be underestimated.   The simulation model utilizes available data about each drug/indication in the industry R&D pipeline, and transforms it using predictive simulation algorithms into a set of metrics characterizing future industry performance.    Industry-wide portfolio simulation model was developed to address short- and long-term portfolio productivity forecasting challenges. The model is drug–centric, it simulates drug development workflow process. The model also incorporates multiple business rules related to drugs interdependence.   The model predicted 2016 drop in NME approvals based on 2014 data. Other modeling experiments include analysis of industry sustainability and innovation strategy, impact of approval rates and likelihood on the variations of clinical trials cycle time, probabilities of success, and FDA approval cycle time.

scholarly journals Memory, not just perception, plays an important role in terrestrial mammalian migration

2017 ◽  
Vol 284 (1855) ◽  
pp. 20170449 ◽  
Author(s):  
Chloe Bracis ◽  
Thomas Mueller
Keyword(s):  
Simulation Model ◽  
Environmental Conditions ◽  
Migration Routes ◽  
Clear Signal ◽  
Individual Based Simulation ◽  
Underlying Mechanisms ◽  
With Memory ◽  
Key Questions

One of the key questions regarding the underlying mechanisms of mammalian land migrations is how animals select where to go. Most studies assume perception of resources as the navigational mechanism. The possible role of memory that would allow forecasting conditions at distant locations and times based on information about environmental conditions from previous years has been little studied. We study migrating zebra in Botswana using an individual-based simulation model, where perceptually guided individuals use currently sensed resources at different perceptual ranges, while memory-guided individuals use long-term averages of past resources to forecast future conditions. We compare simulated individuals guided by perception or memory on resource landscapes of remotely sensed vegetation data to trajectories of GPS-tagged zebras. Our results show that memory provides a clear signal that best directs migrants to their destination compared to perception at even the largest perceptual ranges. Zebras modelled with memory arrived two to four times, or up to 100 km, closer to the migration destination than those using perception. We suggest that memory in addition to perception is important for directing ungulate migration. Furthermore, our findings are important for the conservation of migratory mammals, as memory informing direction suggests migration routes could be relatively inflexible.

scholarly journals Impact of soil erosion on production in cropping systems .I. Development and validation of a simulation model

Soil Research ◽  
1992 ◽  
Vol 30 (5) ◽  
pp. 757 ◽  
Author(s):  
M Littleboy ◽  
DM Silburn ◽  
DM Freebairn ◽  
DR Woodruff ◽  
GL Hammer ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Simulation Model ◽  
Crop Production ◽  
Climatic Variability ◽  
Crop Growth ◽  
Potential Range ◽  
Computer Simulation Model ◽  
Small Catchment ◽  
The Impact

A computer simulation model to analyse risks of soil erosion to long-term crop production is described. The model, called PERFECT, simulates interactions between soil type, climate, fallow management strategy and crop sequence. It contains six main modules; data input, water balance, crop growth, crop residue, erosion and model output. Modules are arranged in a framework that allows alternative modules to be used as required for the potential range of applications. The model contains dynamic crop growth models for wheat, sorghum and sunflower. Validation of PERFECT against small catchment and contour bay data collected throughout Queensland showed that PERFECT explained up to 84% of the variation in total available soil water, 89% of the variation in daily runoff, and up to 75% of the variation in grain yield. Average annual soil erosion was accurately predicted but daily erosion totals were less accurate due to the exclusion of rainfall intensity in erosion prediction. Variability in climate dominates agricultural production in the subtropical region of Australia. The validated model can be coupled with long-term climate and soils databases to simulate probabilities of production and erosion risks due to climatic variability. It provides a method to determine the impact of soil erosion on long-term productivity.

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