Vensim

The significance of environmental protection is well known in today's world. The execution of any program depends on sufficient knowledge and required familiarity with environment and its pollutants. Taking advantage of a systematic method, as a new science, in environmental planning can solve many problems. In this article, air pollution in Tehran and its relationship with health and population growth have been analyzed using dynamic systems. Firstly, by using casual loops, the relationship between the parameters effective on air pollution in Tehran were taken into consideration, then these casual loops were turned into flow diagrams, and finally, they were simulated using the software Vensim in order to conclude what the effect of each parameter will be on air pollution in Tehran in the next 10 years, how changing of one or more parameters influences other parameters, and which parameter among all other parameters requires to be controlled more.

In recent years, the growing population and the need to supply water for domestic, and health, and agriculture sectors have led to the establishment of industrial centers in developing countries. The onset of drought in most countries has challenged surface water, groundwater, dams, and reservoirs. Iran is among those countries, which is located in a dry and semi-arid region.  These factors made managers and decision-makers in this field make appropriate rules and regulations for the use of limited water resources. In this paper, the Vensim dynamic model was applied to properly exploit the Yamchi Dam water and groundwater resources in the Ardabil plain in Iran and allocate these resources in the agriculture, industry, and drinking sectors. By defining different scenarios, it was found that pressurized irrigation and changing the crop pattern scenarios are the most appropriate options for water management in the Yamchi basin. In this scenario, known as G in the model, 62% of the netw...

Dengan berkembangnya pasar global yang kian pesat serta bertambahnya kompetitor yang ada di sektor industri, maka perusahaan dituntut untuk melakukan suatu inovasi agar dapat bertahan. Salah satu inovasi yang dapat dilakukan adalah peningkatan kinerja suatu perusahaan, dimana dalam upaya tersebut secara tidak langsung dapat meningkatkan hubungan antara perusahaan dengan pelanggan khususnya dalam hal pendistribusian hasil produksi perusahaan. Dari upaya tersebut dapat memberikan dampak positif bagi perusahaan, mengingat semakin tingginya kompetisi dalam pasar global, maka hal tersebut merupakan tantangan bagi perusahaan untuk dapat beradaptasi secara tanggap dengan permasalahan yang terjadi. PT. Semen Gresik (Persero) Tbk, merupakan salah satu BUMN terbesar di Indonesia dan mempunyai andil yang besar dalam sektor industri semen. Dari hasil semen yang diproduksi, dilakukan pendistribusian kepada para pelanggannya. Salah satu sasaran dari pendistribusian semen adalah bag/zak, karena alokasi produksi semen bag/zak ± sebesar 80%, sedangkan bulk/curah ± sebesar 20% dari total keseluruhan produksi. Dari proses distribusi yang dilakukan, maka perusahaan dapat mengetahui bagaimana kinerja perusahaan menurut pelanggan dan tujuan dari proses bisnis perusahaan.
Mengacu pada proses distribusi semen terhadap kinerja perusahaan, maka metode yang ditawarkan dalam tugas akhir ini adalah pendekatan dengan model sistem dinamik, dan data yang digunakan adalah data pendistribusian semen yang dilakukan oleh pabrik kepada para pelanggan. Dari karakteristik sistem yang ada, maka dilakukan pemodelan sistem pada proses distribusi semen guna untuk peningkatan kinerja perusahaan dengan didukung adanya faktor – faktor yang mempengaruhi. Faktor – faktor tersebut diantaranya pelanggan PT. Semen Gresik (Persero) Tbk, jumlah demand semen, biaya pengiriman, distribusi, kepuasan pelanggan, pendapatan, harga semen, profit, tingkat pelayanan pelanggan dan kinerja perusahaan. Dengan dilakukannya Analisis Proses Distribusi Semen Bag/Zak untuk Meningkatkan Kinerja Perusahaan dengan Pendekatan Model Sistem Dinamik, diharapkan PT. Semen Gresik (Persero) Tbk dapat mengetahui kinerja perusahaan yang sedang dijalankan serta dapat meningkatkan kinerja perusahaan baik secara internal maupun eksternal, sehingga tujuan dari proses bisnis dapat tercapai sesuai dari apa yang diinginkan.

Kata Kunci : Distribusi, Pemodelan, Model Sistem Dinamik, dan Kinerja Perusahaan.

Global water scarcity is becoming a constraint for human development. Therefore there is a need to enhance water productivity of the irrigated and rainfed agriculture to meet the increasing food demand due to the population growth. This paper describes modeling efforts to assess present and future water needs for food, people and environment. This exercise is being carried out by the International Commission on Irrigation and Drainage (ICID) in five countries, China, Egypt, India, Mexico, and Pakistan, which together cover 51% of irrigated area and 43% population in the world. This paper presents two modeling frameworks including the food security approach of the International Water Management Institute (IWMI) through policy dialogue model (PODIUM), an environmental approach i.e. the Basin wide Holistic Integrated Water Assessment (BHIWA) model and its system dynamic version using VenSim environment.

Background and Objectives: One of the most important issues for mankind in the present century is access to water resources. Increasing population growth and expanding industry have made agricultural development in arid and semi-arid regions a major challenge. The depletion of water resources and the critical situation in the drinking, agricultural, industrial and environmental sectors are a major problem. An essential principle is the relative balance of water supply and demand that emerges with the creation of a comprehensive water management system.
Materials and Methods: The present study was carried out in Hirmand catchment in Sistan area, focusing on the issue of Hirmand river flow and the volume of Chah Nimeh. In order to control the alignment of Chah Nimeh, modeling steps were developed and the basis of the problem was investigated in the process of forming flow-storage diagrams. Using Vensim software, the effect of each variable was simulated on the problem and the calibration and model validation were fitted to different methods such as statistical tests.
Results: The results of the tests show that the model corresponds to reality and the model behavior is consistent with the behavior of the system in reality. According to the statistical tests performed, between the observed and simulated values for the well reserves variable, the coefficient of determination is equal to 0.84, the root mean square error (RSME) is equal to 0.25 and the Nash-Sutcliffe criterion is equal to It is 0.77 in 2019. According to the findings, the demand for various agricultural, drinking and environmental needs will increase in the coming years. The total demand in 1410 will increase from 1350.01 to 1515.93 million cubic meters, which will be impossible to meet the needs despite the reduction of system resources. The largest increase in demand will be in the agricultural and drinking sectors.The results of the scenarios show that the policies of 70% irrigation efficiency in the agricultural sector and reduction of water losses (reduction of evaporation by 50%) based on the proposed scenarios were implemented by the model.
Conclusion: The results show that the irrigation efficiency policies of 70% in the agricultural sector and the reduction of water losses (reduction of evaporation by 50%) based on the proposed scenarios were implemented by the model. Examining the results of these scenarios, it is seen that each of these solutions will reduce water shortage in the coming years, but the best result has been achieved in the first scenario (70% irrigation efficiency in the agricultural sector). In general, the findings show that the continuation of the current consumption trend and, consequently, the continued withdrawal of water resources with the same trend, will have irreparable effects. In this situation, modeling optimal consumption in different sectors, observing limit conditions and creating a culture based on non-extravagance is one of the key issues in crisis management and is one of the most basic foundations of consumption management.

In recent years, the growing population and the need to supply water for domestic, and health, and agriculture sectors have led to the establishment of industrial centers in developing countries. The onset of drought in most countries has challenged surface water, groundwater, dams, and reservoirs. Iran is among those countries, which is located in a dry and semi-arid region. These factors made managers and decision-makers in this field make appropriate rules and regulations for the use of limited water resources. In this paper, the Vensim dynamic model was applied to properly exploit the Yamchi dam water and groundwater resources in the Ardabil plain in Iran and allocate these resources in the agriculture, industry, and drinking sectors. By defining different scenarios, it was found that pressurized irrigation and changing the crop pattern scenarios are the most appropriate options for water management in the Yamchi basin. In this scenario, known as G in the model, 62 % of the network lands are moved from traditional flood to pressurized irrigation with an irrigation efficiency of 60 %. Accordingly, the reliability of the agricultural and drinking water supply will reach 92 and 99 %, respectively. Meanwhile, due to saving the water resources, the water infiltration caused by irrigation will be greatly reduced, and the land swamping will be prevented.

In recent years, the growing population and the need to supply water for domestic, and health, and agriculture sectors have led to the establishment of industrial centers in developing countries. The onset of drought in most countries has challenged surface water, groundwater, dams, and reservoirs. Iran is among those countries, which is located in a dry and semi-arid region. These factors made managers and decision-makers in this field make appropriate rules and regulations for the use of limited water resources. In this paper, the Vensim dynamic model was applied to properly exploit the Yamchi dam water and groundwater resources in the Ardabil plain in Iran and allocate these resources in the agriculture, industry, and drinking sectors. By defining different scenarios, it was found that pressurized irrigation and changing the crop pattern scenarios are the most appropriate options for water management in the Yamchi basin. In this scenario, known as G in the model, 62 % of the netw...

Production of horticultural crops in Sleman District is dominated by salacca-pondoh with total production in 2016 reaching 73 kton, cover up to 98% of total salacca-pondoh’s production in Yogyakarta Province. But salacca-pondoh’s farmers actually got very low-price during harvest season and they only act as a price taker that had low bargaining position, so that their welfare. This research formulated salacca-pondoh’s business as usual condition in Sleman District in form of system dynamic simulation. The factors influenced the low income of farmers during harvest season were identified. Result showed there are several seasonal “pitfalls” points in the farmer’s income which made it dropped far below the average value. It has potential to make the farmers not to replant salacca-pondoh then switch to other fruits that are more profitable. Product diversification either vertically or horizontally by allocating some of the fruit and waste to be convert into derivative products can be a step to increase the income of salacca-pondoh’s farmers and intensify the economic activity in Sleman District.

In recent years, the growing population and the need to supply water for domestic, and health, and agriculture sectors have led to the establishment of industrial centers in developing countries. The onset of drought in most countries has challenged surface water, groundwater, dams, and reservoirs. Iran is among those countries, which is located in a dry and semi-arid region. These factors made managers and decision-makers in this field make appropriate rules and regulations for the use of limited water resources. In this paper, the Vensim dynamic model was applied to properly exploit the Yamchi dam water and groundwater resources in the Ardabil plain in Iran and allocate these resources in the agriculture, industry, and drinking sectors. By defining different scenarios, it was found that pressurized irrigation and changing the crop pattern scenarios are the most appropriate options for water management in the Yamchi basin. In this scenario, known as G in the model, 62 % of the network lands are moved from traditional flood to pressurized irrigation with an irrigation efficiency of 60 %. Accordingly, the reliability of the agricultural and drinking water supply will reach 92 and 99 %, respectively. Meanwhile, due to saving the water resources, the water infiltration caused by irrigation will be greatly reduced, and the land swamping will be prevented.

The production of salacca-pondoh at Sleman District in 2016 reaches 73 kton where this production covers up to 98% of total production in Yogyakarta Province, but in fact the farmers in the region actually got the low price during great harvest season, where the selling price dropped to less than Rp3000 per kg, which made the farmers had a weak bargaining position and impacted to their walfare. In this study the problem is successfully captured in systems dynamic simulation results for the business as usual (BaU) model where there are seasonal pitfalls on farmers' income. The scenario for derivative business procurement (raw materials based on fruit and waste) provides a significant increase in farmers’ income compared to BaU and able to reduce the number of unemployement in Sleman District with the probability of sales of derivative products at least 48.97%. It takes a probability value of more than 41.67% for successful academic research program to get greater income than business as usual and more than 89.42% to get that from derivative procurement program. Scenario of derivative business procurement + fruit sales + academic research program + business credit program (code ABG2) gives the highest value on farmers’ income. While the scenario of derivative business procurement + fruit sales + business credit program (BG2 code) gives the highest BC ratio value. Further model’s development can be done with the addition of new variables, combine with decision making & optimization method, and transform it to more practical form.