Simulation Results Of Scenarios Research Articles

Blockchain-driven framework for construction waste recycling and reuse

Conventional management mechanisms for construction waste recycling and reuse (CWRR) often cause considerable information asymmetry, inadequate government supervision, and imperfect incentive mechanisms, resulting in frequent illegal dumping and landfilling of construction waste and relatively low recycling rates. To address these issues, we introduce blockchain technology to CWRR. The design science research methodology was adopted to identify the main steps in functional requirement identification and blockchain framework development for CWRR. To explain how blockchain can improve the CWRR process, a conceptual model for the functional requirements of the proposed framework was constructed using qualitative analysis. A blockchain-driven framework was developed to overcome practical barriers in the CWRR industry. Based on scenario simulation results, the proposed framework had execution and transaction costs of $4.735 and $1.276, respectively, and latency performance at the millisecond level. The results indicate that (1) based on specific problems systematically identified from CWRR practices, the proposed framework can address practical barriers in the CWRR industry more directly; (2) the CWRR industry can use blockchain technology to achieve information sharing, comprehensive government supervision, and effective incentive mechanisms and (3) the blockchain-driven framework has high efficacy and can promote efficient CWRR and high-quality development of CWRR industry chain. This management model is conducive to forming a collaborative CWRR industry chain that can lead to broader adoption of blockchain technology across industries.

Cooperative Vehicle Localization in Multi-Sensor Multi-Vehicle Systems Based on an Interval Split Covariance Intersection Filter with Fault Detection and Exclusion

In the cooperative multi-sensor multi-vehicle (MSMV) localization domain, the data incest problem yields inconsistent data fusion results, thereby reducing the accuracy of vehicle localization. In order to address this problem, we propose the interval split covariance intersection filter (ISCIF). At first, the proposed ISCIF method is applied to the absolute positioning step. Then, we combine the interval constraint propagation (ICP) method and the proposed ISCIF method to realize relative positioning. Additionally, in order to enhance the robustness of the MSMV localization system, a Kullback–Leibler divergence (KLD)-based fault detection and exclusion (FDE) method is implemented in our system. Three simulations were carried out: Simulation scenarios 1 and 2 aimed to assess the accuracy of the proposed ISCIF with various capabilities of absolute vehicle positioning, while simulation scenario 3 was designed to evaluate the localization performance when faults were present. The simulation results of scenarios 1 and 2 demonstrated that our proposed vehicle localization method reduced the root mean square error (RMSE) by 8.9% and 15.5%, respectively, compared to the conventional split covariance intersection filter (SCIF) method. The simulation results of scenario 3 indicated that the implemented FDE method could effectively reduce the RMSE of vehicles (by about 55%) when faults were present in the system.

Study on seasonal floating treatment wetland combination water purification based on numerical simulation

The North Canal Basin, Tianjin, section in Wuqing urban area is subject to multi-source pollution from its surroundings and exhibits characteristics of a stagnant water body. As an urban landscape water body, there is immense pressure to improve its water environment and quality. During the 13th Five-Year Plan, China's “Major Special Project for Water Pollution Control and Treatment Technology” conducted research and demonstration of remediation technologies for this river section. Three water quality indexes, ammonia nitrogen (NH3-N), total phosphorus (TP), and chemical oxygen demand (COD) were improved to some extent. In this study, based on the experimental results of the water special project and the achievements of the two-dimensional hydrodynamic water quality model of this river section, nine different Floating Treatment Wetland (FTW) combination schemes were designed for the summer, autumn, and winter without changing the original ratio of FTW in the demonstration project. The scenario simulation results indicate that the optimal FTW combination schemes for the three seasons are A3, B1, and C2, respectively; the water purification effects of each optimal FTW combination scheme are superior to those of the original demonstration project, with the removal rate performance of the optimal scenario simulations for the three seasons being B1 > C2 > A3. Further single-factor evaluation of water quality under the nine FTW combination schemes reveals that each scheme significantly improves the water quality of North Canal Basin in different seasons, with the best removal effect achieved in autumn, reaching Class IV water quality, followed by winter and summer, both achieving Class V water quality. The results of this study can provide guidance for devising aquatic plant arrangements that meet water quality standards in different regions and offer a theoretical basis for the sustainable development of water quality purification in different seasons for northern rivers, taking the example of North Canal Basin.

Analysis of PM2.5 Synergistic Governance Path from a Socio-Economic Perspective: A Case Study of Guangdong Province

Analyzing the influencing factors of PM2.5 concentration, scenario simulations, and countermeasure research to address the problem of PM2.5 pollution in Guangdong Province is of great significance for governments at all levels for formulating relevant policies. In this study, the ChinaHighPM2.5 dataset and economic and social statistics for Guangdong Province from 2010 to 2019 were selected, and a PM2.5 pollution management compliance path formulation method based on the multi-scenario simulation was proposed by combining the differences in city types and PM2.5 concentration prediction. Based on the prediction model of PM2.5 concentration constructed by the Ridge and SVM models and facing the PM2.5 pollution control target in 2025, the urban PM2.5 pollution control scenario considering the characteristics of urban development was constructed. According to the scenario simulation results of the PM2.5 prediction model, the PM2.5 pollution control path suitable for Guangdong Province during the 14th Five-Year Plan period was explored. The coupling coordination model was used to explore the spatial and temporal pattern evolution of PM2.5 pollution collaborative governance in various prefecture-level cities under the standard path, and the policy recommendations for PM2.5 pollution control during the 14th Five-Year Plan period are proposed. The results showed the following: ① in the case of small samples, the model can provide effective simulation predictions for the study of urban pollutant management compliance pathways. ② Under the scenario of PM2.5 management meeting the standard, in 2025, the annual average mass concentration of PM2.5 in all prefecture-level cities in Guangdong Province will be lower than 22 μg/m3, and the annual average concentration of PM2.5 in the whole province will drop from 25.91 μg/m3 to 21.04 μg/m3, which will fulfil the goal of reducing the annual average concentration of PM2.5 in the whole province to below 22 μg/m3, as set out in the 14th Five-Year Plan for the Ecological Environmental Protection of Guangdong Province. ③ Under the path of PM2.5 control and attainment, the regional coordination relationship among prefecture-level cities in Guangdong Province is gradually optimized, the number of intermediate-level coordinated cities will increase, and the overall spatial distribution pattern will be low in the middle and high in the surrounding area. Based on the characteristics of the four city types, it is recommended that a staggered development strategy be implemented to achieve synergy between economic development and environmental quality. Urban type I should focus on restructuring freight transportation to reduce urban pollutant emissions. City type II should focus on urban transportation and greening. For city type III, the focus should be on optimizing the industrial structure, adjusting the freight structure, and increasing the greening rate of the city. For city type IV, industrial upgrading, energy efficiency, freight structure, and management of industrial pollutant emissions should be strengthened.

Assessment of village resilience in flood storage areas based on complex networks: From the perspective of safety and low-carbon development

This study has built a modified gravity model to quantify the connection strength between villages, and complex networks were used to analyze and deconstruct the resilience characteristics of network structure and simulated resilience change characteristics under different scenarios including climate change, and identified the network core of the villages. The improvement of the resilience levels of rural systems under changing environments is an important sustainable development. The objective of this study is to provide a basis for the construction of rural emergency disaster prevention in flood storage areas and provide a reference for sustainable rural low-carbon development of village system. The results show that (1) from the perspective of spatial patterns of rural networks, there are obvious spatial differences in Mengwa rural network, showing a spindle-shaped spatial structure with dense middle and sparse on both sides. (2) From the perspective of structural resilience characteristics, the network has significant hierarchy and agglomeration, high local transmission and no obvious characteristics of homogeneity or heterogeneity. Amongst them, the core node has a prominent position, strong control ability and significant correlation effect. (3) The results of scenario simulations on rural network resilience show deliberate disturbance can significantly reduce network resilience compared with random disturbance. A large number of high-energy consumption and low-efficiency phenomena occur earlier in the network, leading to the collapse of the network.

Evaluation of the Impact of Groundwater Management Policies Under Climate and Economic Changes in Tunisia

This study develops a hydro-economic model for the coastal aquifer Mahdia Ksour Essef in Tunisia in order to analyze how external shocks (climate change, energy price increase) and management policies can affect groundwater sustainability during the coming decades. Twenty-one scenarios covering three management policies (free market, partial cooperation, and full cooperation policy) under various potential climate and economic changes are evaluated. The results of scenario simulations show the potential impact of energy soaring prices and climate change on the aquifer’s water table level, groundwater extractions, cropland areas, and farmers’ benefits under each policy option in the future. They also show that the best scenario to address the effects of climate change would need to take into account environmental externalities and efficient energy prices. The findings of this study are very important in the context of climate change and uncertain global energy markets and provide feasible alternatives to preserve the regional economy and aquifer sustainability.

5G NR Network Planning Analysis using 700 Mhz and 2.3 Ghz Frequency in The Jababeka Industrial Area

This research designed a 5G NR network using 700 MHz and 2.3 GHz frequencies with 30 MHz bandwidth in the Jababeka industrial area covering an area of 5600 hectares. The Propagation Model used by Urban Macrocell (UMa) in non line of sight (NLOS) conditions according to 3GPP TR 38901 standard with Synchronization signal-reference signal received power (SS-RSRP) and Synchronization Signal to Interference and Noise Ratio (SS-SINR) parameters. Coverage prediction simulation using Atoll 3.4 consists of 4 scenarios. Scenario 1 uses a frequency of 2.3 GHz downlink, scenario 2 uses a frequency of 2.3 GHz uplink, scenario 3 uses a frequency of 700 MHz downlink and scenario 4 uses a frequency of 700 MHz uplink. Parameters analyzed were signal strength (SS-RSRP > -110 dBm) and signal quality (SS-SINR > 5 dB). The simulation results of scenario 1 get a signal strength of 61% and signal quality of 73.71% from the Jababeka area. Scenario 2 gets 100% for signal strength and 75.35% for signal quality. Scenario 3 gets a signal strength of 72.27% and signal quality of 85.30%. Scenario 4 shows a signal strength of 100% and signal quality of 71.04% from the Jababeka area. Planning with a frequency of 700 MHz shows that the signal strength and signal strength parameters are better than the 2.3 GHz frequency, making it suitable for 5G networks in the Jababeka area. The findings of this study are intended to help Indonesian cellular operators plan and deploy their 5G network.

Simulasi Sistem Dinamis Bahan Pangan Tambahan Guna Pemenuhan Kebutuhan Konsumen dan Peningkatan Keuntungan Petani

Shallots (Allium cepa var ascalonicum L.) is one of the most popular food additives in Indonesia. These ingredients are used to add flavor to Indonesian cuisine. The increase in community needs caused by the increase in population has an impact on increasing the demand for shallots every year. This increase also occurred in Bantul Regency. The demand for shallots in Bantul is not accompanied by a balance in the amount of supply obtained from shallot-producing areas. This is because most farmers in Bantul Regency only plant shallots in the dry season. Therefore, this study seeks to propose how to balance the supply of shallots by farmers with market demand to increase farmers' profits. This study uses a dynamic system simulation approach with the help of Powersim studio 9 software. The first step is to build a Causal Loop Diagram (CLD) to see the causal or reciprocal relationship between variances and stock-flow diagrams to compile a mathematical formulation of the system model. dynamic. The simulation results are then validated to determine the credibility of the model. After the model is declared valid, 3 (three) scenarios of implementing the strategy in the shallot supply chain model will be generated. The best model scenario simulation results are scenario 1 (one), namely by replacing the use of tuber seeds in all activities.

Impact of the Grain for Green Project on water resources and ecological water stress in the Yanhe River Basin.

The Grain for Green project (GGP), initialized by the Chinese government in 1999, has achieved substantial achievements accompanied by a decrease in surface runoff on the Loess Plateau, but the impacts of large-scale afforestation on regional water resources are uncertain. Hence, the objective of this study was to explore the impact of land use change on generalized water resources and ecological water stress using the blue and green water concepts, taking the Yanhe River Basin as the case study. The Soil and Water Assessment Tool (SWAT) was applied to quantify the green water and blue water, which are defined as generalized water resources. The ecological water requirement of vegetation (forest and grass), agricultural water footprint and virtual water flow are considered regional water requirements. The land use types of 1980 (Scenario I) and 2017 (Scenario II) were entered into the SWAT model while keeping the other parameters constant to isolate the influence of land use changes. The results show that the average annual differences in blue, green and generalized water resources were -72.08 million m3, 24.34 million m3, and -47.74 million m3, respectively, when the simulation results of Scenario II were subtracted from those of Scenario I, which shows that land use change caused by the GGP led to a decrease in blue and generalized water resources and an increase in green water resources. Surface runoff in Scenario I was more than that in Scenario II in all of the years of the study period from 1980–2017, and green water storage in Scenario I was more than that in Scenario II in all of the years of the study period except in 1998; although lateral flow in Scenario I was less than that in Scenario II except in 2000 and 2015, as was groundwater runoff in 1992, 2000 and 2015, and green water flow in 1998. Blue water flow, green water storage and green water flow in Scenario II were less than those in Scenario I in the whole basin, 12.89 percent of the basin and 99.21 percent of the basin, respectively. The total water footprint increased from 1995 to 2010 because the forest water footprint increased significantly in this period, although the agricultural water footprint and grass water footprint decreased. The ecological water stress index values had no obvious temporal change trends in either land use scenario, but the ecological water stress index in Scenario II was greater than that in Scenario I, which illustrates that the GGP led to an increase in ecological water stress from the perspective of generalized water resources.

Policy Instruments for the Improvement of Customers’ Willingness to Purchase Electric Vehicles: A Case Study in Iran

Given the various advantages of electric vehicles compared to conventional gasoline vehicles in terms of energy efficiency and environmental pollution (among others), this paper studies the factors affecting customers’ willingness to purchase electric vehicles. An integrated discrete choice and agent-based approach is applied to model the customers’ choice for the valuation of electric vehicles based on the internal reference price. The agent-based model evaluates customers’ preferences for a number of personal and vehicle attributes, according to which vehicle they chose. Data from 376 respondents are collected to estimate a random-parameter logit model where customers are asked to reveal their preferences about five attributes of electric vehicles, including travel range, top speed, charge cost, government incentives, and price. The role of social networks of customers and their threshold purchase price is also examined in the agent-based model. The scenario simulation results indicate that the allocation of government incentives for electric vehicles, decreasing electric vehicle/non-electric vehicle price gap, expanding electric vehicle travel range, increasing gasoline prices, and enhancing electric vehicle top speed stimulate electric vehicle market shares, respectively.

Spatiotemporal Dynamics of Ecological Security Pattern of Urban Agglomerations in Yangtze River Delta Based on LUCC Simulation

Urbanization has not only promoted economic development, but also significantly changed land use and development strategy. The environmental problems brought by urbanization threaten ecological security directly. Therefore, it is necessary to introduce changes in land use when constructing an ecological security pattern. This study takes the Yangtze River Delta urban agglomeration, one of the most economically developed regions in China, as the research area. Based on its land use status, the Cellular Automata–Markov model was used to predict the quantitative change and transfer of land-use types in 2025, and three types of land-use patterns were simulated under different scenarios. Combined with the pressure–state–response model, the Entropy TOPSIS comprehensive evaluation model is used to evaluate the three phases in the years of 2005, 2010, and 2015, and the results indicated that the safety level dropped from 85.45% to 82.94%. Five spatial associations were obtained from the spatial autocorrelation analysis using GeoDA, and the clustering distribution of the three phases was roughly the same. Based on the requirements of “Natural Growth” scenario, “Urban Sprawl” scenario, and “Ecological Protection” scenario, the transfer matrix of the various land-use types were modified rationally. The results of scenario simulations illustrated that the level of urbanization was inversely proportional to the level of ecological security. The surrounding cities in the northern part of Taihu Lake were developing rapidly, with low levels of ecological security. The hilly cities in the southern part, in contrast, developed slowly and had a high level of ecological security. Based on the temporal and spatial changes in the ecosystem, an ecosystem optimization model was proposed to determine the ecological functional areas. The nature of each functional area provided the basis to formulate urban construction and management plans and achieve sustainable urban development.

STUDI TERHADAP UNJUK KERJA PEMBANGKIT LISTRIK TENAGA SURYA ATAP KANTOR DESA PADANGSAMBIAN KAJA

The Padangsambian Kaja Village Government in Denpasar City through the SDGsprogram from the Ministry of Villages, Development of Disadvantaged Regions andTransmigration has implemented clean and renewable energy. The power plant being operatedis the rooftop solar power plant with a capacity of 7,2 kWp which is connected to the PLNnetwork. The study was conducted to determine the performance of the installed solar powerplant with the help of HelioScope software simulation. Energy production will be comparedbetween the simulation results of the 2 scenarios with the results of monitoring on the inverter inthe period from May to July 2021, so that it will be known the factors that influence theproduction of solar power plant energy. The results show the potential for energy productioneach year from the simulation results of scenario 1 and scenario 2 respectively are 9.964 kWhand 10.306 kWh, and the simulation results for energy production in the period from May to Julyin scenario 1 and scenario 2 respectively are 2.937,3 kWh and 3.057,8 kWh. Energy productionfrom scenario 1 and scenario 2 simulation is higher than real energy production, with adifference of 180,9 kWh with a percentage of 6,1% for scenario 1, and 301,4 kWh with apercentage of 9,8% for scenario 2.

An Empirical Study on System Dynamics Model for Sustainable Development of Air Traffic Control Units

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.

The Impact of Population Aging on Housing Demand in China Based on System Dynamics

In recent years, the proportion of China’s elderly population is gradually increasing, and the real estate market is changing dramatically. Consequently the impact of population aging on housing demand has become increasingly prominent. On the theoretical basis of the relationship between population aging, family structure and housing demand, this paper firstly constructs a system dynamics model of the impact of population aging and family structure on housing demand in China. Then, the model is simulated, and several scenarios of population, family structure, and real estate policies are set up. The main conclusions of this paper are as follows: China’s population will rise at first and then decrease, reaching a peak of 1.401 billion by 2023. As the proportion of elderly population increases, the degree of population aging is becoming increasingly serious. The size of the family will gradually shrink to 2.39 people per household in 2050. The housing demand will increase first and then decrease. Through the results of scenario simulation, this paper puts forward the following suggestion to effectively balance the housing demand in China: Completely relaxing family planning policies, imposing a real estate tax, canceling the pre-sale policy, and raising the loan rate.

城市花粉致敏植物种类构成、分布与潜在危害评估——以深圳市为例

气传致敏花粉会引发过敏症，且可通过每年在花粉季的反复接触逐渐加重，危害人体健康，严重时甚至危害生命。花粉致敏植物在城市中被广泛引种栽培，导致城市花粉症患者数量激增。以深圳市为案例，基于建成区600个样地的实地调查数据，分析花粉致敏植物的种类构成与时空分布，通过构建花粉浓度及花粉致敏危害潜力计算公式，评估花粉致敏危害潜力及其分布特点。结果显示：①调查记录到深圳市建成区花粉致敏植物46科92属186种，其中外来种占43.37%，其中美洲、亚洲和大洋洲来源占国外外来种的81.00%。花粉致敏植物种数以公园绿地最多，达126种。植物花粉致敏等级以Ⅰ级为主，达154种。②花粉致敏植物的盛花期为春夏季，占全年累计开花种数的65.02%。最高峰出现在8月，开花种数达92种。 ③花粉浓度潜力最高值也出现在8月，占全年总值的12.13%。豆科和禾本科植物贡献比例较大，分别占乔木和草本总值的40.86%和64.13%。龙岗区花粉浓度潜力占比较高，占各季花粉量的26.06%-29.42%。④冬春两季各样地花粉致敏危害等级均不高，但夏秋季有些样地达到二级重度危害。罗湖区调查样地全年花粉致敏危害等级均较低，光明区在春夏秋季致敏危害等级皆较高。高危害等级样地主要出现在附属绿地及公园绿地。⑤花粉致敏植物防控措施情景模拟结果，去除主要花粉致敏植物种类比降低所有花粉致敏植物的花粉浓度潜力更有效。本研究为城市花粉致敏植物的管理、规划、养护和研究提供参考。;Airborne allergenic pollen can cause pollinosis and aggravate every year through repeated exposure in the pollen seasons, endangering human health and even life in severe cases. Allergenic pollen plants have been widely introduced and cultivated in cities, leading to a sharp increase in the number of urban pollinosis patients. In this study, based on the investigation data of 600 plots in the built-up area of Shenzhen as a case study, the species composition and the spatiotemporal distribution of allergenic pollen plants were analyzed, and the potential allergenic hazard with its distribution characteristics was evaluated by constructing calculation formulas of pollen concentration and pollen allergenic potential. The results showed that: ① In the built-up area of Shenzhen, a total of 186 species of allergenic pollen plants from 46 families and 92 genera were recorded. Among the allergenic pollen plant species, 43.37% were alien species, with 81.00% of them originated from America, Asia, and Oceania. The number of allergenic pollen plant species was highest in park green space, up to 126. Allergenic levels were mainly graded Ⅰ, covering 154 species. ② The peak bloom stages of allergenic pollen plants were spring and summer, with flowering species accounted for 65.02% of the annual total. The peak month appeared in August, concerning 92 flowering species. ③ August had the highest potential value of pollen concentrations, accounting for 12.13% of the annual year total. The contribution of Leguminosae and Poaceae were relatively high, respectively, accounting for 40.86% and 64.13% of the arbors and the herbs totals. The values in the Longgang District were relatively high in all seasons, reaching 26.06%-29.42% of respectively seasonal total. ④ The allergenic hazard levels in all plots were not high in winter and spring, but some plots reached second-level severe in summer and autumn. The hazard levels of investigated plots in the Luohu District were relatively low throughout the year. In contrast, those of investigated plots in the Guangming District were relatively high in spring, summer, and autumn. The high-hazard-level plots mainly appeared in the subsidiary green space and park green space. ⑤ Results of scenario-simulation for allergenic pollen plants prevention and control measures showed that the effect of removing major allergenic pollen plant species might be better than that of reducing the pollen concentrations of all allergenic pollen plant species. This study provides a reference for the management, planning, and maintenance of urban allergenic pollen plants, and the research and solution of urban pollen allergenic problems.

CO2 emissions inequality through the lens of developing countries

There is increasing interest in CO2 emissions inequality between and within countries, and concerns about the impacts of COVID-19 on vulnerable groups. In this study, the CO2 emissions inequality based on the different consumption category data of disaggregated income groups in eight developing countries is analyzed with the application of input-output model. We further examine the effects of the COVID-19 outbreak on CO2 emissions inequality based on the hypothetical extraction method, and the results reveal that the outbreak has decreased the CO2 emissions inequality and emissions over time. However, the shared socioeconomic pathway scenario simulation results indicate that long-term CO2 emissions inequality will persist. Targeted poverty elimination measures improve the utility of the low- and lowest-income groups and reduce CO2 emissions inequality. Reducing the excessive consumption on the demand side as well as improving the energy efficiency and increasing the share of renewable energy in the energy consumption on the supply side will provide more informed options to achieve multiple desirable outcomes, such as poverty elimination and climate change mitigation.

Impacts of Increasing Private Charging Piles on Electric Vehicles’ Charging Profiles: A Case Study in Hefei City, China

Electric vehicles (EVs) and charging piles have been growing rapidly in China in the last five years. Private charging piles are widely adopted in major cities and have partly changed the charging behaviors of EV users. Based on the charging data of EVs in Hefei, China, this study aims to assess the impacts of increasing private charging piles and smart charging application on EVs’ charging load profiles. The charging load profiles of three types of charging piles which are public, employee-shared, and private ones, are simulated in three different scenarios. The results of scenario simulation indicate that the increase in EVs will reinforce the peak value of the total power load, while increasing private charging piles and the participation rate of smart charging piles will have peak-load shifting effects on the power load on weekdays. Specifically, 12% of the charging load will be shifted from public piles to private ones if the ratio of EVs and private piles increases from 5:3 to 5:4. The adoption of smart charging in private piles will transfer 18% of the charging load from the daytime to the night to achieve peak-load shifting. In summary, promoting the adoption of private piles and smart charging technology will reshape the charging load profile of the city, but the change will possibly reduce the utilization rate of public charging piles. The results suggest that urban governments should consider the growth potential of private piles and promote smart charging in charging infrastructure planning.

A system dynamics model for disease management in poultry production

The objective of this article was to provide the nonmodeler reader of Poultry Science, an overview of the system dynamics modeling method (SDM) through development of a broiler house disease management simulator (BHDMS). System dynamics modeling uses feedback theory and computer-aided simulation to help elucidate relationships between factors in complex systems, which may be circular or interrupted with long delays. Materials used to build the simulator include data from literature and industry indices. The methods used were the steps in SDM, namely: 1) Identify the problem and boundaries; 2) develop a dynamic hypothesis explaining cause of the problem; 3) build the causal loop diagram (CLD); 4) develop the stock and flow model; 5) conduct model simulations; and 6) model validation. Results presented here are the CLD and stock and flow model of the simulator, results of scenario simulations, and model validity tests. The simulator consists of the main model, the disease submodel, and the antimicrobial use submodel. The main model represents a cycle of production in the broiler house of a specified length of time, which repeats after a specified down time. The disease submodel shows population dynamics in the broiler house in terms of changes over time in number of susceptible, infected, recovered, and dead birds. Production parameters that could be modified in the model include delivery size, grow-out period, down time, and efficacy of antimicrobials. Disease mortality levels, above the set threshold, trigger antimicrobial use in the model. The model showed the effect of antimicrobial use intervention on the population dynamics, namely, on the proportion of the susceptible, infected, recovered, and dead birds in the population. Thus, the BHDMS was able to simulate the effect of the intervention on population dynamics and would facilitate evaluating management interventions such as antimicrobial use.

Agroecological food web modelling to evaluate and design organic and conventional agricultural systems

The question of whether organic or conventional agriculture is most suitable for meeting world food requirements and improving resilience to climate change is the topic of much current research. Most comparisons, however, focus either on output efficiency such as yields or on impacts of different nutrient management strategies on the sustainability of the agrosystems, and the impacts of each on the agricultural food webs and beneficial insects responsible for pest control – or outbreaks – has been often overlooked. While standard cropping models can explain if, why and how organic nutrient and crop management work and how they should be adapted to climate change, the lack of mechanistic models of agroecology prevents us from explaining why and how passive and active biocontrol and integrated pest management function, when they do not function, and what optimal management strategies could be employed.In this research, we show that agroecological food web models calibrated with field population dynamics data can be used to demonstrate the mechanisms behind food web dynamics that have been previously observed in the field. Results of scenario simulations show that chemical control provides immediate relief from pest pressures, but at high risk of later pest resurgence if control is not repeated; on the contrary, biological control requires more time to reduce pest populations to acceptable levels but with minimal risk of causing resurgence. In all cases, success of pest control measures is highly dependent on the date of action. In addition, the use of modelling tools to optimise biological control application dates led to much better control than either fixed date or pest population threshold-based applications. These analyses and resulting integrated pest management intervention recommendations are only possible with agroecological food web population dynamics models.We encourage future studies to examine more complex food webs from a variety of agroecosystems to test whether functional responses differ significantly, and hope that this approach will succeed in bringing agroecological food web predictive modelling to the level where it can routinely be used as a decision-making support tool, as hydrological and crop models are employed today.

Evaluation of Listen Before Talk (LBT) mechanism fairness at LTE-Licensed Assisted Access (LAA) against Wi-Fi 5 GHz

LTE Release 13 allow the use of unlicensed frequency variations called Licensed Assisted Access (LAA). Combination of licensed LTE is used as primary cells to carry information and transport traffic data. Whereas the unlicensed spectrum is used as secondary cells that are proposed to increase capacity and distribute the spectrum fairly. The simulation results of scenario 1 produce a fairness index of 64 users for FTP over UDP in scenario 1 of 0.998, scenario 2 is 0.857 and scenario 3 is 0.997. Whereas for FTP over TCP in scenario 1 is 0.779, scenario 2 is 0.639 and scenario 3 is 0.74.