scholarly journals A generic system dynamics model for simulating and evaluating the hydrological performance of reconstructed watersheds

2009 ◽  
Vol 13 (6) ◽  
pp. 865-881 ◽  
Author(s):  
N. Keshta ◽  
A. Elshorbagy ◽  
S. Carey
Keyword(s):  
System Dynamics ◽  
Soil Cover ◽  
Dynamics Model ◽  
Water Balance Components ◽  
Absolute Relative Error ◽  
Short And Long Term ◽  
The Mean ◽  
Natural Watersheds ◽  
Generic System

Abstract. A generic system dynamics watershed (GSDW) model is developed and applied to five reconstructed watersheds located in the Athabasca mining basin, Alberta, Canada, and one natural watershed (boreal forest) located in Saskatchewan, Canada, to simulate various hydrological processes in reconstructed and natural watersheds. This paper uses the root mean square error (RMSE), the mean absolute relative error (MARE), and the correlation coefficient (R) as the main performance indicators, in addition to the visual comparison. For the South Bison Hills (SBH), South West Sand Storage (SWSS) and Old Aspen (OA) simulated soil moisture, the RMSE values ranges between 2.5–4.8 mm, and the MARE ranges from 7% to 18%, except for the D2-cover it was 26% for the validation year. The R statistics ranges from 0.3 to 0.77 during the validation period. The error between the measured and simulated cumulative actual evapotranspiration (AET) flux for the SWSS, SBH, and the OA sites were 2%, 5%, and 8%, respectively. The developed GSDW model enables the investigation of the utility of different soil cover designs and evaluation of their performance. The model is capable of capturing the dynamics of water balance components, and may used to conduct short- and long- term predictions under different climate scenarios.

scholarly journals A generic system dynamics model for simulating and evaluating the hydrological performance of reconstructed watersheds

2008 ◽  
Vol 5 (3) ◽  
pp. 1441-1478 ◽  
Author(s):  
N. Keshta ◽  
A. Elshorbagy ◽  
A. Barr
Keyword(s):  
System Dynamics ◽  
Oil Sands ◽  
Soil Cover ◽  
Natural Soil ◽  
Water Balance Components ◽  
Short And Long Term ◽  
Natural Watersheds ◽  
Reconstructed Soil ◽  
Alternative Designs ◽  
Generic System

Abstract. The mining of oil sands in northern Alberta, Canada, involves the stripping and salvage of surface soil layers to gain access to the oil mines. The oil sands industry has committed to reconstructing these disturbed watersheds to replicate the performance of the natural soil horizons and to reproduce the various functions of natural watersheds. The selection of the texture and thickness of the reconstructed soil cover layers is based primarily on the concept that all covers must have sufficient moisture for vegetation over the growing season. Assessment of the hydrological performance of the reconstructed soil covers is crucial to select the best cover alternative. A generic system dynamics watershed (GSDW) model is developed, based on the existing site-specific SDW model, and applied to five reconstructed watersheds located in the Athabasca mining basin, Alberta, Canada; and one natural watershed (boreal forest) located in Saskatchewan, Canada; to simulate the various hydrological processes; in particular, soil moisture patterns and actual evapotranspiration, in reconstructed and natural watersheds. The model is capable of capturing the dynamics of the water balance components in both reconstructed and natural watersheds. The developed GSDW model provides a vital tool, which enables the investigation of the utility of different soil cover alternative designs and evaluation of their performance. Moreover, the model can be used to conduct short- and long- term predictions under different climate scenarios.

scholarly journals Transforming a Liability into an Asset: A System Dynamics Model for Free-Ranging Dog Population Management

Systems ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 56
Author(s):  
Urmila Basu Mallick ◽  
Marja H. Bakermans ◽  
Khalid Saeed
Keyword(s):  
System Dynamics ◽  
Social Integration ◽  
Unintended Consequences ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
Innovative Strategies ◽  
Management Context ◽  
Free Ranging ◽  
Social Rewards

Using Indian free-ranging dogs (FRD) as a case study, we propose a novel intervention of social integration alongside previously proposed methods for dealing with FRD populations. Our study subsumes population dynamics, funding avenues, and innovative strategies to maintain FRD welfare and provide societal benefits. We develop a comprehensive system dynamics model, featuring identifiable parameters customizable for any management context and imperative for successfully planning a widescale FRD population intervention. We examine policy resistance and simulate conventional interventions alongside the proposed social integration effort to compare monetary and social rewards, as well as costs and unintended consequences. For challenging socioeconomic ecological contexts, policy resistance is best overcome by shifting priority strategically between social integration and conventional techniques. The results suggest that social integration can financially support a long-term FRD intervention, while transforming a “pest” population into a resource for animal-assisted health interventions, law enforcement, and conservation efforts.

scholarly journals Testing successful Business Model using System Dynamics

2019 ◽  
Vol 7 ◽  
pp. 91
Author(s):  
J. Ganzarain ◽  
M. Ruiz ◽  
J.I. Igartua
Keyword(s):  
System Dynamics ◽  
Business Model ◽  
Business Models ◽  
Industrial Sector ◽  
Continuous Change ◽  
Dynamic Complexity ◽  
Holistic View ◽  
Short And Long Term ◽  
Systemic View

In our increasingly globalised economy, managing continuous change whilst remaining competitive and dynamic has become a central issue for firms in the industrial sector. One of the elements for obtaining this competitiveness is the value creation model of the firm. The most important challenges in firms are characterised by dynamic complexity which makes it difficult to understand factors in their context. Consequently management and decision making is hindered (Antunes et al., 2011). Business models are characterised by complexity and dynamism. Performance of the firm is a complex topic determined by the large amount of variables that can be involved in the system, and the different effects that influence the system in the short and long term. Due to this complexity a systemic view is required, that is, an holistic view of the whole system. Such a systemic view enables managers to make decisions based on evidence rather than intuition and personal experiences, as they understand how the whole system works. Thus, the main aim of this research is to use an empirical tool such as System Dynamics (SD), to support and sustain firms in the identification of new constructs related to their Business Model (BM).

scholarly journals A System Dynamics Model of Online Stores’ Sales: Positive and Negative E-WOM and Promotion Perspective

2019 ◽  
Vol 11 (21) ◽  
pp. 6045 ◽  
Author(s):  
Qiang Yan ◽  
Simin Zhou ◽  
Xiaoyan Zhang ◽  
Ye Li
Keyword(s):  
System Dynamics ◽  
Real Data ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
Sustainable Operations ◽  
Main Research ◽  
Interaction Diagram ◽  
Online Stores ◽  
The Impact

In this paper, we build a causal interaction diagram between the factors that may influence the sales and profits of online stores. An online store’s real operation data were used to help determine the causal relationship between variables. Finally, we proposed a system dynamics model and conducted a simulation of the operation of an online store. In this model, we focused on the impact of promotion and positive/negative electronic word of mouth (e-WOM) on the sales and profits of the online stores. The simulation results showed a similar trend to the real data and the main research finding showed that promotion is not a long-term measure for the sustainable development of online stores. Excessive promotion effort may lead to consumers’ dissatisfaction leading the increase of negative e-WOM. The systematic simulation can help us understand better the long-term effect of promotion and e-WOM on the operation of online stores. Finally, we gave some management suggestions for online stores’ sustainable operations.

Towards a Methodology for Monitoring and Analyzing the Supply Chain Behavior

2011 ◽  
pp. 186-208
Author(s):  
Reinaldo Moraga ◽  
Luis Rabelo ◽  
Alfonso Sarmiento
Keyword(s):  
Neural Networks ◽  
Sensitivity Analysis ◽  
Supply Chain ◽  
System Dynamics ◽  
Eigenvalue Analysis ◽  
Background Information ◽  
Short And Long Term ◽  
And Performance

In this chapter, the authors present general steps towards a methodology that contributes to the advancement of prediction and mitigation of undesirable supply chain behavior within short- and long- term horizons by promoting a better understanding of the structure that determines the behavior modes. Through the integration of tools such as system dynamics, neural networks, eigenvalue analysis, and sensitivity analysis, this methodology (1) captures the dynamics of the supply chain, (2) detects changes and predicts the behavior based on these changes, and (3) defines needed modifications to mitigate the unwanted behaviors and performance. In the following sections, some background information is given from literature, the general steps of the proposed methodology are discussed, and finally a case study is briefly summarized.

scholarly journals Bariatric surgery in patients with type 1 diabetes: special considerations are warranted

2019 ◽  
Vol 10 ◽  
pp. 204201881882220 ◽  
Author(s):  
Zohar Landau ◽  
Galit Kowen-Sandbank ◽  
Daniela Jakubowicz ◽  
Asnat Raziel ◽  
Nasser Sakran ◽  
...  
Keyword(s):  
Bariatric Surgery ◽  
Type 1 Diabetes ◽  
Diabetic Ketoacidosis ◽  
Glucose Control ◽  
Healthcare Services ◽  
Short And Long Term ◽  
The Mean

Objective: We examined short and long-term outcomes of bariatric surgery in patients with obesity and type 1 diabetes mellitus (T1DM). Methods: We reviewed the records of all adults insured by Maccabi Healthcare Services during 2010 -2015, with body mass index (BMI) ⩾30 kg/m2 and T1DM; and compared weight reduction and glucose control according to the performance of bariatric surgery. BMI and glycated hemoglobin (HbA1c) levels were extracted for baseline and every 6 months, for a mean 3.5 years. Results: Of 52 patients, 26(50%) underwent bariatric surgery. Those who underwent surgery were more often female and with a longer duration of diabetes. Immediately postoperative, 4(15%) developed diabetic ketoacidosis, while 6(23%) experienced severe hypoglycemic episodes. The mean BMI decreased among surgery patients: from 39.5±4.4 to 30.1±5.0 kg/m2 ( p < 0.0001); and increased among those who did not undergo surgery: from 33.6±3.9 to 35.1±4.4 kg/m2 ( p = 0.49). The mean HbA1c level decreased during the first 6 months postoperative: from 8.5±0.9% to 7.9±0.9%; however, at the end of follow-up, was similar to baseline, 8.6±2.0% (p = 0.87). For patients who did not undergo surgery, the mean HbA1c increased from 7.9±1.9% to 8.6±1.5% ( p = 0.09). Conclusions: Among individuals with obesity and T1DM, weight loss was successful after bariatric surgery, but glucose control did not improve. The postoperative risks of diabetic ketoacidosis and severe hypoglycemic episodes should be considering when performing bariatric surgery in this population.

scholarly journals The Balanced Scorecard and the Strategic Learning Process: A System Dynamics Modeling Approach

2015 ◽  
Vol 2015 ◽  
pp. 1-20 ◽  
Author(s):  
Steen Nielsen ◽  
Erland H. Nielsen
Keyword(s):  
System Dynamics ◽  
Balanced Scorecard ◽  
Measurement Model ◽  
Quantitative Model ◽  
Strategic Learning ◽  
Dynamics Modeling ◽  
The Balanced Scorecard ◽  
Short And Long Term ◽  
Methodological Aspects

The main purpose of this paper is to improve on the conceptual as well as the methodological aspects of BSC as a quantitative model by combining elements from traditional balanced scorecard (BSC) thinking with the Systems Thinking. This is done by combining short and long term aspects of measurements. The result is then used to build and construct a balanced scorecard model for strategic learning with the specific aim to maintain satisfied customers and motivated employees. Strategic planning, operational execution, feedback, and learning are some of the most important key features of any performance measurement model. This paper aims to address not only the conceptual domain related to BSC, that is, learning and system dynamics causality and feedback, but also the methodological domain concept of precision solved by differential equations. Our results show how a potential move from a static strategic vision map to a linked and dynamic understanding may be not fully realistic but very useful for learning purposes. The new knowledge obtained from the learning feedbacks fertilizes both decision discussion and decision-making and what may be required in order to move to the next level of BSC and system dynamics integration.

scholarly journals Frequency of osteoporosis in patients with peptic ulcer disease

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Amber Amin ◽  
Qaisar Farooq ◽  
Rizwan Jameel
Keyword(s):  
Peptic Ulcer ◽  
Peptic Ulcer Disease ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Ulcer Disease ◽  
Short And Long Term ◽  
The Common ◽  
The Mean ◽  
Age Range

BACKGROUND & OBJECTIVE: Peptic ulcer disease (PUD) is one of the common presentations in the medical as well as Gastroenterology clinics and it can end up in various short- and long-term complications among which osteoporosis is highly under rated. Therefore, the present study was designed to determine the frequency of osteoporosis in cases having PUD. METHODOLOGY: A cross-sectional study was conducted at the Department of Medicine during 1st January 2020 to 30th June 2020 in Sheikh Zayed Hospital, Lahore. The diagnosed cases of PUD on the basis of history and endoscopic findings with the age range of 20 to 60 years were included. Osteoporosis was labelled as yes, where a T-score of ≤ -2.5 on DEXA scan was noted. RESULTS: In this study, there were a total of 139 cases, out of which 75 (53.95%) were males and 64 (46.05%) females. The mean age of the participants was 48.11±9.43 years. Osteoporosis was observed in 14 (10.07%) out of 139 cases. Osteoporosis was seen in 05 (6.67%) males vs 09 (14.06%) females in their respective groups with p= 0.148. Osteoporosis was observed in 4 (5.80%) cases with a duration of PUD up to 2 years and 10 (14.28%) cases with duration more than this with p= 0.096 CONCLUSION: Osteoporosis is not uncommon in cases with Peptic ulcer disease, and there is no significant association with any of the confounders of this study.

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