Comprehensive System Model Research Articles

An interval gas flow analysis in natural gas and electricity coupled networks considering the uncertainty of wind power

The wide application of renewable energy sources in power systems has a significant influence on both electrical and tightly coupled systems. The aim of this paper is to build a comprehensive system model of a natural gas and electricity coupled network. The concept of distributed stack nodes was introduced to overcome the shortcoming of adjusting active power by a single gas-fired unit to achieve power balance. On this basis, the impact of the active power output uncertainty of wind farms was studied, and the interval flow of the natural gas system was analyzed by two proposed methods. The results were compared with Monte Carlo stochastic simulation. Case studies demonstrated the effectiveness of the proposed method and led to the conclusion that the uncertainty of wind power has a significant impact on the steady-state operation of natural gas systems. Interval solutions could provide great insights into the operating and planning of coupled systems with wind power uncertainty.

A modelling system with adjustable emission inventories for cross-boundary air quality management in Hong Kong and the Pearl River Delta, China

Air quality problems are attracting much attention in Hong Kong (HK) and the Pearl River Delta (PRD) in China. The complex and regional characteristics of air quality problems call for a comprehensive modelling system with a highly reliable simulation and effective communication tools for decision-makers and participants from multiple disciplines. In this paper, we used a modelling management method to develop a Cyberinfrastructure system that couples meteorological and air quality models with a visual analysis to improve the cognition and management of air quality problems. The database management of both the data and the modelling parameters is an innovative advantage of this system; this will be helpful not only for sharing modelling knowledge but also for improving the acknowledgement of modelling scenarios, which are usually conducted by various stakeholders. On the basis of 19 categories of emission inventories that provide detailed information about multiple pollutants in the 11 cities in the study area, this system provides an authoritative and adjustable emission inventory to draw an accurate scientific picture for decision-makers. We applied this system to a case study to investigate the effects of emission control of nitrogen dioxide from vehicles in HK and the PRD on air quality. The simulation showed that the air quality improvement from emission control was very limited and suggested that regional and super-regional co-operation involving the comprehensive emission control of multiple pollutants may be more effective in creating a better future.

Unified Power Flow Analysis in Natural Gas and Electricity Coupled Networks Considering the Uncertainty of Wind Power

Abstract The widely application of renewable energy in power system makes a big influence on the system security and stability. The main work of this paper was building a comprehensive system model of a natural gas and electricity coupled network and analyzing the steady-state power flow of the coupled network. On this basis, this paper further studied the impact of uncertainty of wind power, and analyzed the interval range of the variables of natural gas system using interval algorithm. The analysis and case studies led to the conclusion that the uncertainty of wind power has a significant impact on the security of natural gas system.

Development of a model for activated sludge aeration systems: linking air supply, distribution, and demand.

During the design of a water resource recovery facility, it is becoming industry practice to use simulation software to assist with process design. Aeration is one of the key components of the activated sludge process, and is one of the most important aspects of modelling wastewater treatment systems. However, aeration systems are typically not modelled in detail in most wastewater treatment process modelling studies. A comprehensive dynamic aeration system model has been developed that captures both air supply and demand. The model includes sub-models for blowers, pipes, fittings, and valves. An extended diffuser model predicts both oxygen transfer efficiency within an aeration basin and pressure drop across the diffusers. The aeration system model allows engineers to analyse aeration systems as a whole to determine biological air requirements, blower performance, air distribution, control valve impacts, controller design and tuning, and energy costs. This enables engineers to trouble-shoot the entire aeration system including process, equipment and controls. It also allows much more realistic design of these highly complex systems.

Performance investigation of low – Concentration photovoltaic systems under hot and arid conditions: Experimental and numerical results

In this study, a comparative performance analysis was performed between a conventional photovoltaic system and a low-concentration photovoltaic system. Two typical photovoltaic modules and two compound parabolic concentrating photovoltaicsystems were examined. A Cooling system was employed to lower the temperature of the solar cells in each of the two configurations. Experimental and numerical investigations of the performance of the two arrangements with and without cooling were presented. Experiments were conducted outdoors at the Egypt-Japan University of Science and Technology, subjected to the hot climate conditions of New Borg El-Arab City, Alexandria, Egypt (Longitude/Latitude: E 029°42′/N 30°55′). A comprehensive system model was established, which comprises an optical model, coupled with thermal and electrical models. The coupled model was developed analytically and solved numerically, using MATLAB software, to assess the overall performance of the two configurations, considering the concentration ratio of the concentrated photovoltaic system to be 2.4X. The results indicated that cooling the solar panels considerably improved the electrical power yield of the photovoltaic systems. By employing cooling, the temperatures of the conventional photovoltaic system and the concentrated photovoltaic system were effectively lowered by approximately 25% and 30%, respectively, resulting in a significant enhancement in the electrical power output of the photovoltaic system by 11% and that of the concentrated photovoltaic system by 15%. Furthermore, the results revealed that the concentrated photovoltaic system outperformed the non-concentrated photovoltaic system, for both non-cooling and cooling cases, by 33% and 52%, respectively. Finally, experimental verification of the numerical results revealed a good agreement for both configurations, with an average error of 4% and 5% for the photovoltaic systems and the concentrated photovoltaic systems, respectively.

Modeling the cost-effectiveness of stormwater best management practices in an urban watershed in Las Vegas Valley

The Las Vegas Valley is one of the fastest growing urban areas in the United States. Any future urbanization and climate change, especially if the climate becomes wetter and there are more intense and frequent storm events, will undoubtedly cause excessive urban stormwater runoff and exacerbate flooding in the Valley. Stormwater management is therefore one of the key challenges to the local government. The main goal of this study was to ascertain the utility of Best management Practices (BMPs) in mitigating stormwater runoff in the Duck Creek watershed in the Las Vegas Valley. The cost-effectiveness of different BMPs were also compared so as to determine the best BMP arrangement under the current and future climate and land use change conditions. By applying SUSTAIN (System for Urban Stormwater Treatment and Analysis INtegration) as a comprehensive GIS-based modeling and decision support system in the BMP analyses, modeling results show that although the installation of the existing three detention basins in the watershed can provide a 9% flow reduction, these three detention basins alone will not be adequate in the future with the impending changes in climate and land use. To alleviate the potential problems of water resources, SUSTAIN was further used to determine the number of additional BMPs required, the optimal types of BMPs (such as, detention and infiltration BMPs), and their locations in reducing storm runoff in the watershed under the future land-use and climate regimes. By comparing the performances of five potential BMP implementation scenarios, it was found that a mixed implementation of one additional detention BMP and one infiltration BMP to the existing detention BMPs in the downstream area of the watershed would be the most cost-effective stormwater runoff control solution in face of future urbanization and climate change. Depending on the locations of the new detention and infiltration BMPs, surface flow, even without BMP retrofit options, could be reduced by 27–31%. The cost for such installations would range from $1,141,000 to $1,319,000. This information may be useful to local planners and water resource managers in their efforts to develop alternative stormwater management plans in the arid Southwest.

Levels of SysML Compatibility for Collaborative Human System Development

Developing human centered systems across multiple design and development teams requires a common framework to ensure seamless transition of models between collaborators. It is not sufficient to simply exchange data that is syntactically correct, it is also important to ensure that the information exchanged has shared meaning among team members. A current design project that included human architecting, human performance modeling and system engineering teams provided the foundation for a level of compatibility framework for Model Based System Engineering (MBSE) using the System Modeling Language (SysML). This framework provides descriptions of four different levels of model maturity that can be used for collaborative development. At each stage, the benefits of the model are described as well as its limitations. The Levels of SysML Compatibility can be used to integrate the Human Views, Soldier System library models and IMPRINT simulations to produce a comprehensive human system modeling approach.

Statistical indicators of Arctic sea-ice stability – prospects and limitations

Abstract. We examine the relationship between the mean and the variability of Arctic sea-ice coverage and volume in a large range of climates from globally ice-covered to globally ice-free conditions. Using a hierarchy of two column models and several comprehensive Earth system models, we consolidate the results of earlier studies and show that mechanisms found in simple models also dominate the interannual variability of Arctic sea ice in complex models. In contrast to predictions based on very idealised dynamical systems, we find a consistent and robust decrease of variance and autocorrelation of sea-ice volume before summer sea ice is lost. We attribute this to the fact that thinner ice can adjust more quickly to perturbations. Thereafter, the autocorrelation increases, mainly because it becomes dominated by the ocean water's large heat capacity when the ice-free season becomes longer. We show that these changes are robust to the nature and origin of climate variability in the models and do not depend on whether Arctic sea-ice loss occurs abruptly or irreversibly. We also show that our climate is changing too rapidly to detect reliable changes in autocorrelation of annual time series. Based on these results, the prospects of detecting statistical early warning signals before an abrupt sea-ice loss at a "tipping point" seem very limited. However, the robust relation between state and variability can be useful to build simple stochastic climate models and to make inferences about past and future sea-ice variability from only short observations or reconstructions.

TH-AB-209-06: An Investigation of the Feasibility of Malignant Lesion Detection During Routine Breast Cancer Screening Using a Prototype Acousto-Optic Transmission Ultrasound Imaging System

Purpose: To investigate the feasibility of malignant lesion detection during routine breast cancer screening using an acousto-optic (AO) transmission ultrasound imaging system, particularly in premenopausal women with high breast density. Methods: A full-field, single-projection ultrasound imaging system was developed that uses a high-resolution AO detector to convert the acoustic intensity transmitted through the compressed breast into a visual image by virtue of the AO effect in nematic liquid crystals. In this work, a comprehensive system model was proposed to describe the AO imaging process, including the generation of the incident acoustic field by the transducer, the propagation of the field through the breast tissue, and the conversion of the transmitted acoustic field intensity into a visual image. Validation of the imaging model was achieved through comparison of actual AO breast phantom images with simulated images based on the proposed model. Malignant lesion detectability studies were subsequently performed in simulation using homogeneous and heterogeneous numerical breast phantoms. Results: Comparison of actual AO breast phantom images with simulated images based on the proposed system model showed strong agreement, with an RMSE less than 4%. Lesion detectability studies using homogeneous numerical breast phantoms demonstrated excellent visibility for breast lesions as small as 0.5 cm and source frequencies on the order of 4 MHz. Though lesion detectability proved immune to spatial variations in mass density (2%) and attenuation (15%) in the breast parenchyma, minor variations in parenchymal sound speed (1.3%) resulted in substantial refraction artifacts that compromised the diagnostic utility of the prototype system. Conclusions: Differences in acoustic absorption may overcome refraction and enhance lesion visibility at conventional breast ultrasound frequencies (10 to 15 MHz). However, provided the FDA limit on the incident acoustic intensity (1 W/cm2) is employed, such high-frequency imaging will require improvements in the current AO detector sensitivity (10−6 W/cm2). Department of Defense (DOD) Breast Cancer Research Program IDEA Award W81XWH-11-1-0332; National Institutes of Health (NIH) Grant T32 EB002103-24 from the National Institute of Biomedical Imaging and Bioengineering (NIBIB)

해외도시개발 지원 종합정보시스템 구축방안

ABSTRACT This research aims to build a total information system that systematizes existing sporadic information, which may lead to revitalization and efficiency of overseas urban development. To achieve this, this study firstly analyses the current information systems for urban development in foreign countries and information from the private sector. The results show that the information system that operates in the domestic agencies, are less likely to involve the contents related to information sharing, social network building and business process. However, that used in agencies ordering the overseas urban development projects, mostly provides the information of professionals, project participants and their business. Second, this research selects the information to be provided by the integrated information system and proposes a data collection plan. The information, required to push forward urban development in abroad, is classified into seven categories. Third, this study establishes a target model of comprehensive information system and makes suggestions for institutional improvement. For doing this, it categorizes overseas urban development information, links to classified information, organizes the system into three stages to services through informational channels, and then suggests a target model. Furthermore, it proposes institutional improvement to achieve efficiency of information systems through a comprehensive review of the similar cases such as administrative system of architecture(Seumter) and land information system.Key words : Overseas Urban Development, Information System

Modeling and dynamics simulation for deformable objects of orthotropic materials

Simulation of physically based deformable models is a hot topic in computer graphics. Most of the existing models focus on isotropic materials and some on transversely isotropic materials. We propose a modeling method for orthotropic materials, which exhibits different mechanical behaviors along three orthogonal directions. First, constraints for the strain energy density in linear elastic models are analyzed, and a positive-definite elasticity tensor is derived for an orthotropic material. Second, an orthotropic deformation controlling frame-field is conceptualized and a frame construction tool is developed for users to define the desired material properties. A quaternion Laplacian smoothing algorithm is proposed, and several user-defined rotation minimizing frames are propagated into the entire body of the deformable object, which forms a smooth frame-field. Third, the corotational linear FEM model coupled with the orthonormal frame-field is formulated to realize a dynamics system, which can deal with large deformations. All the algorithms have been implemented in a comprehensive modeling and simulation system, and a GUI is provided to design the orthotropic model. Experiments on real-time deformation simulation and analytical comparisons are presented.

Comprehensive modelling study on observed new particle formation at the SORPES station in Nanjing, China

Abstract. New particle formation (NPF) has been investigated intensively during the last 2 decades because of its influence on aerosol population and the possible contribution to cloud condensation nuclei. However, intensive measurements and modelling activities on this topic in urban metropolitan areas in China with frequent high-pollution episodes are still very limited. This study provides results from a comprehensive modelling study on the occurrence of NPF events in the western part of the Yangtze River Delta (YRD) region, China. The comprehensive modelling system, which combines the WRF-Chem (the Weather Research and Forecasting model coupled with Chemistry) regional chemical transport model and the MALTE-BOX sectional box model (the model to predict new aerosol formation in the lower troposphere), was shown to be capable of simulating atmospheric nucleation and subsequent growth. Here we present a detailed discussion of three typical NPF days, during which the measured air masses were notably influenced by either anthropogenic activities, biogenic emissions, or mixed ocean and continental sources. Overall, simulated NPF events were generally in good agreement with the corresponding measurements, enabling us to get further insights into NPF processes in the YRD region. Based on the simulations, we conclude that biogenic organic compounds, particularly monoterpenes, play an essential role in the initial condensational growth of newly formed clusters through their low-volatility oxidation products. Although some uncertainties remain in this modelling system, this method provides a possibility to better understand particle formation and growth processes.

Long term climate change mitigation goals under the nuclear phase out policy: The Swiss energy system transition

The Swiss electricity system is dominated by low-carbon hydro and nuclear generation. The Government's decision to phase-out nuclear energy exacerbates Switzerland's climate change mitigation goals. Response to this challenge requires systemic changes to the energy system, which is generally a long-term, uncertain and systemic process, affected by technology choices across the entire energy system. A comprehensive Swiss TIMES Energy system Model (STEM) with high temporal detail has been developed for the analysis of plausible low-carbon energy pathways focusing on uncertainties related to policy (climate change mitigation and acceptability of new centralised electricity generation) and international fuel prices. Increasing electrification of end-uses is seen across the scenarios, resulting in continuous growth in electricity demands. The electrification of heating and e-mobility substitute direct use of fossil fuels in end-use sectors and contribute to a significant carbon dioxide emission (CO2) reduction. Centralised gas power plants and renewables become key source of electricity supply. Given the phaseout of nuclear generation, clear policy signals are required to ensure capacity is built to achieve a low-carbon energy system. At the same time, it is also essential to ensure consistency between the electricity sector and end-use energy policies. For the long-term carbon reduction target, some non-cost-effective conservation measures are important early in the period because they are available only at the time of building renovation.

Implementation of the Community Earth System Model (CESM) version 1.2.1 as a new base model into version 2.50 of the MESSy framework

Abstract. The Community Earth System Model (CESM1), maintained by the United States National Centre for Atmospheric Research (NCAR) is connected with the Modular Earth Submodel System (MESSy). For the MESSy user community, this offers many new possibilities. The option to use the Community Atmosphere Model (CAM) atmospheric dynamical cores, especially the state-of-the-art spectral element (SE) core, as an alternative to the ECHAM5 spectral transform dynamical core will provide scientific and computational advances for atmospheric chemistry and climate modelling with MESSy. The well-established finite volume core from CESM1(CAM) is also made available. This offers the possibility to compare three different atmospheric dynamical cores within MESSy. Additionally, the CESM1 land, river, sea ice, glaciers and ocean component models can be used in CESM1/MESSy simulations, allowing the use of MESSy as a comprehensive Earth system model (ESM). For CESM1/MESSy set-ups, the MESSy process and diagnostic submodels for atmospheric physics and chemistry are used together with one of the CESM1(CAM) dynamical cores; the generic (infrastructure) submodels support the atmospheric model component. The other CESM1 component models, as well as the coupling between them, use the original CESM1 infrastructure code and libraries; moreover, in future developments these can also be replaced by the MESSy framework. Here, we describe the structure and capabilities of CESM1/MESSy, document the code changes in CESM1 and MESSy, and introduce several simulations as example applications of the system. The Supplements provide further comparisons with the ECHAM5/MESSy atmospheric chemistry (EMAC) model and document the technical aspects of the connection in detail.

Simulating the Dynamics of E-waste Production from Mobile Phone: Model Development and Case Study of Rwanda

Mobile phone sales and stocks showed an exponential growth in the past years globally and the annual number of mobile phones produced surpassed one billion in 2007. This soaring growth of related e-waste deserves sufficient attentions paid to it regionally and globally, since 40% of its total weight is made from metallic, of which 12 elements are identified to be highly hazardous. Different methods from different part of the world have been used to estimate the obsolete mobile phones but none has developed a dynamic model and handled the discrepancy resulting from improper approach and error in the input data. This study aimed to develop a comprehensive dynamic system model for simulating the dynamism of e-waste production from mobile phone specifically for African developing countries and to prevail over the previous errors. The logistic model method combined with Stella program were used to carry out this study. Then the simulation for Rwanda was conducted and compared with others countries’ results as model testing and validation. The results showed that Rwanda produced about 1.5 million obsolete mobile phones with 125 tons of waste in 2014 and e-waste production peak would appear in 2017. It is expected to reach 4.2 million obsoletes with 352 tons by 2020 along with environmental impact intensity of 21 times of 2005. Moreover, e-waste management policy for developing countries specifically for Rwanda has been suggested to reduce environmental impact up to 40% in 2020 and to 73% in 2030. The present study figured out the dynamism characteristic and outflow of the system design. It is concluded through the model testing and validation that the present dynamic model is competent and could deal with mobile phone e-waste production.

A STUDY ON THE IMPROVEMENT OF CADASTRAL SYSTEM IN MONGOLIA – FOCUSED ON NATIONAL LAND INFORMATION SYSTEM

Abstract. National land information system (NLIS) is an essential part of the Mongolian land reform. NLIS is a web based and centralized system which covers administration of cadastral database all over the country among land departments. Current ongoing NLIS implementation is vital to improve the cadastral system in Mongolia. This study is intended to define existing problems in current Mongolian cadastral system and propose administrative institutional and systematic implementation through NLIS. Once NLIS launches with proposed model of comprehensive cadastral system it will lead to not only economic and sustainable development but also contribute to citizens’ satisfaction and lessen the burdensomeness of bureaucracy. Moreover, prevention of land conflicts, especially in metropolitan area as well as gathering land tax and fees. Furthermore after establishment of NLIS, it is advisable that connecting NLIS to other relevant state administrational organizations or institutions that have relevant database system. Connections with other relevant organizations will facilitate not only smooth and productive workflow but also offer reliable and more valuable information by its systemic integration with NLIS.

A comparative study of the modeled effects of atrazine on aquatic plant communities in midwestern streams.

Potential effects of atrazine on the nontarget aquatic plants characteristic of lower-order streams in the Midwestern United States were previously assessed using the Comprehensive Aquatic System Model (CASMATZ ). Another similar bioenergetics-based, mechanistic model, AQUATOX, was examined in the present study, with 3 objectives: 1) to develop an AQUATOX model simulation similar to the CASMATZ model reference simulation in describing temporal patterns of biomass production by modeled plant populations, 2) to examine the implications of the different approaches used by the models in deriving plant community-based levels of concern (LOCs) for atrazine, and 3) to determine the feasibility of implementing alternative ecological models to assess ecological impacts of atrazine on lower-order Midwestern streams. The results of the present comparative modeling study demonstrated that a similar reference simulation to that from the CASMATZ model could be developed using the AQUATOX model. It was also determined that development of LOCs and identification of streams with exposures in excess of the LOCs were feasible with the AQUATOX model. Compared with the CASMATZ model results, however, the AQUATOX model consistently produced higher estimates of LOCs and generated non-monotonic variations of atrazine effects with increasing exposures. The results of the present study suggest an opportunity for harmonizing the treatments of toxicity and toxicity parameter estimation in the CASMATZ and the AQUATOX models. Both models appear useful in characterizing the potential impacts of atrazine on nontarget aquatic plant populations in lower-order Midwestern streams. The present model comparison also suggests that, with appropriate parameterization, these process-based models can be used to assess the potential effects of other xenobiotics on stream ecosystems.

Interaction of a Slip-Based Antilock Braking System with Tire Torsional Dynamics

ABSTRACT This paper presents simulation and experimental results that outline the interaction between a tire's torsional dynamic properties and antilock braking system (ABS) during a hard braking event. Previous work has shown the importance of the coupled dynamics of the tire's belt, sidewall, and wheel/hub assembly on braking performance for a wheel acceleration-based ABS controller. This work presents findings based on a proprietary slip-based ABS controller. A comprehensive system model including tire torsional dynamics, dynamics of the tread–ground friction (LuGre friction model), and dominant brake system hydraulic dynamics was developed for simulation studies on this slip-based controller. Results from key sensitivity studies of tire torsional parameters are presented along with experimental results obtained on a quarter car braking test rig. In this work, it was found that within a reasonable tire design space (with respect to tire torsional properties), the ABS algorithm tested was extremely robust to changing these parameters. The main conclusion of this result is that when a consumer replaces his or her tires with different (than original equipment) tires, there should be little effect on braking performance.

Experimental Study and Numerical Model Calibration for Earthquake-Induced Collapse of RC Frames with Emphasis on Key Columns, Joints, and the Overall Structure

A thorough investigation of earthquake-induced collapse of reinforced concrete frames is presented. The inherent correlation between the nonlinear behavior of key components and the collapse mechanism of overall frame is examined through concurrent collapse tests of both frame and key components. Important issues in the component models are investigated through calibration against experiments, leading to a comprehensive structural system model. Both test and simulation indicate that the seismic performance are predominately governed by the key columns, whereas the energy dissipation capacity is somewhat affected by the joints. This study offers systematic experimental data and numerical models for future collapse assessments.

Aerosol chemistry above an extended archipelago of the eastern Mediterranean basin during strong northern winds

Abstract. Detailed aerosol chemical predictions by a comprehensive model system (i.e. PMCAMx, WRF, GEOS-CHEM), along with airborne and ground-based observations, are presented and analysed over a wide domain covering the Aegean Archipelago. The studied period is 10 successive days in 2011, characterized by strong northern winds, which is the most frequently prevailing synoptic pattern during summer. The submicron aerosol load in the lower troposphere above the archipelago is homogenously enriched in sulfate (average modelled and measured submicron sulfate of 5.5 and 5.8 μg m−3, respectively), followed by organics (2.3 and 4.4 μg m−3) and ammonium (1.5 and 1.7 μg m−3). Aerosol concentrations smoothly decline aloft, reaching lower values (< 1 μg m−3) above 4.2 km altitude. The evaluation criteria rate the model results for sulfate, ammonium, chloride, elemental carbon, organic carbon and total PM10 mass concentrations as "good", indicating a satisfactory representation of the aerosol chemistry and precursors. Higher model discrepancies are confined to the highest (e.g. peak sulfate values) and lowest ends (e.g. nitrate) of the airborne aerosol mass size distribution, as well as in airborne organic aerosol concentrations (model underestimation ca. 50 %). The latter is most likely related to the intense fire activity at the eastern Balkan area and the Black Sea coastline, which is not represented in the current model application. The investigation of the effect of local variables on model performance revealed that the best agreement between predictions and observations occurs during high winds from the northeast, as well as for the area confined above the archipelago and up to 2.2 km altitude. The atmospheric ageing of biogenic particles is suggested to be activated in the aerosol chemistry module, when treating organics in a sufficient nitrogen and sulfate-rich environment, such as that over the Aegean basin. More than 70 % of the predicted aerosol mass over the Aegean Archipelago during a representative Etesian episode is related to transport of aerosols and their precursors from outside the modelling domain.