Hasil untuk "River, lake, and water-supply engineering (General)"

Maarten Vlaswinkel, Duarte Antunes, Frank Willems

Decarbonization of the transport sector sets increasingly strict demands to maximize thermal efficiency and minimize greenhouse gas emissions of Internal Combustion Engines. This has led to complex engines with a surge in the number of corresponding tunable parameters in actuator set points and control settings. Automated calibration is therefore essential to keep development time and costs at acceptable levels. In this work, an innovative self-learning calibration method is presented based on in-cylinder pressure curve shaping. This method combines Principal Component Decomposition with constrained Bayesian Optimization. To realize maximal thermal engine efficiency, the optimization problem aims at minimizing the difference between the actual in-cylinder pressure curve and an Idealized Thermodynamic Cycle. By continuously updating a Gaussian Process Regression model of the pressure's Principal Components weights using measurements of the actual operating conditions, the mean in-cylinder pressure curve as well as its uncertainty bounds are learned. This information drives the optimization of calibration parameters, which are automatically adapted while dealing with the risks and uncertainties associated with operational safety and combustion stability. This data-driven method does not require prior knowledge of the system. The proposed method is successfully demonstrated in simulation using a Reactivity Controlled Compression Ignition engine model. The difference between the Gross Indicated Efficiency of the optimal solution found and the true optimum is 0.017%. For this complex engine, the optimal solution was found after 64.4s, which is relatively fast compared to conventional calibration methods.

HU Junfang, ZENG Zhi, LIU Chuncheng

The scarcity of fresh water resources limits the utilization of the combination mode of brackish water and fresh water to some extent. To explore new modes of the safe utilization of brackish water, a pot experiment is conducted to study the effects of mixed irrigation of brackish water and reclaimed water on soil exchangeable ions, total exchangeable bases, cation exchange capacity, exchange sodium percentage (ESP), etc. The results indicate that compared to pure irrigation of brackish water, the mixed irrigation of brackish water and reclaimed water in a 1:1 ratio reduces soil exchangeable sodium ion content, soil exchangeable calcium ion content, total exchangeable bases and cation exchange capacity by 59.43%, 9.47%, 24.88% and 20.82%, respectively, while increasing soil exchangeable magnesium and potassium ion contents by 25.94% and 57.89%, respectively. As the proportion of reclaimed water in the liquid mixture increases, soil exchangeable sodium ion content and ESP gradually significantly decrease, while soil exchangeable magnesium ion content shows a trend of significantly increasing. Total exchangeable bases and base saturation show a trend of gradually decreasing. Soil exchangeable sodium ion content, total exchangeable bases and ESP are all extremely significantly positively correlated with soil moisture, salinity, and water drop penetration time (WDPT) (<italic>P</italic> &lt; 0.01). Additionally, soil exchangeable base saturation is extremely significantly positively correlated with soil moisture and salinity (<italic>P</italic> &lt; 0.01) after the harvest. Both pH and soil total nitrogen (TN) content are extremely significantly negatively correlated with soil exchangeable sodium ion content, total exchangeable bases and ESP (<italic>P</italic> &lt; 0.01), and are significantly negatively correlated with soil exchangeable base saturation (<italic>P</italic> &lt; 0.05). To some extent, the results can provide theoretical reference on new modes of the safe utilization of brackish water.

Ko Hosoda, Mitsuharu Nishikawa, Yasutaka Yasui et al.

Compounds such as 2-methylisoborneol (2-MIB) and geosmin present in the final effluents of wastewater treatment plants may affect water treatment in downstream areas. To reduce the concentrations of 2-MIB and geosmin, we investigated the influence of the returned water from sludge treatment on their concentrations and behaviors during wastewater treatment in the reactor. The inflow of returned water from sludge treatment increased the geosmin concentration in the primary effluent (PE) making it higher than that in the influent. The dissolved 2-MIB concentration in the mixed liquor was higher than that in the PE. However, the geosmin concentration in the mixed liquor tended to be lower than that in the PE as the biological treatment progressed. Laboratory experiments indicated that the 2-MIB and geosmin concentrations varied in the reactor due to their release from activated sludge and removal by aeration and agitation. Our analyses revealed that the return activated sludge substantially impacts 2-MIB concentrations in secondary effluents. Moreover, the geosmin concentration in the reactor decreased, possibly due to removal by aeration and agitation.

Yvonne Dittrich, Johan Bolmsten, Catherine Seidelin

Action research provides the opportunity to explore the usefulness and usability of software engineering methods in industrial settings, and makes it possible to develop methods, tools and techniques with software engineering practitioners. However, as the research moves beyond the observational approach, it requires a different kind of interaction with the software development organisation. This makes action research a challenging endeavour, and it makes it difficult to teach action research through a course that goes beyond explaining the principles. This chapter is intended to support learning and teaching action research, by providing a rich set of examples, and identifying tools that we found helpful in our action research projects. The core of this chapter focusses on our interaction with the participating developers and domain experts, and the organisational setting. This chapter is structured around a set of challenges that reoccurred in the action research projects in which the authors participated. Each section is accompanied by a toolkit that presents related techniques and tools. The exercises are designed to explore the topics, and practise using the tools and techniques presented. We hope the material in this chapter encourages researchers who are new to action research to further explore this promising opportunity.

Nino Krvavica, Marta Marija Gržić, Silvia Innocenti et al.

This study investigates the interactions between tides, storm surge, river flow, and power peaking in the microtidal Neretva River estuary, Croatia. Based on the existing NS_Tide tool, the study proposes a new non-stationary harmonic model adapted for microtidal conditions, which incorporates linear storm surge, as well as linear and quadratic river discharge terms. This model enhances the NS_Tide's ability to accurately predict water levels from tide-dominated sections downstream to discharge-dominated areas upstream. River discharge was identified as the dominant factor for predicting stage levels at most stations, while the influence of storm surge, though consistent, decreased upstream. Strong tide-river interactions were observed throughout the study domain, with the stationary tidal component consistently contributing to water level fluctuations at all locations, and minimal influence from the tide-surge interaction component. Simulations using the STREAM numerical model were also used to isolate the variability in water levels caused by power peaking. These simulations demonstrated that high-frequency discharge fluctuations due to hydropower plant operations amplify the $S_1$ constituent in upstream river sections and modulate the amplitudes of other tidal constituents in the estuarine and tidal river sections. The proposed method proved highly effective in the microtidal context of the Neretva River and shows potential for adaptation to mesotidal and macrotidal systems.

Bakhtiyor E. Adenbayev, Salauat B. Kalabaev

Lake Dzhyltyrbas is one of the water bodies of great importance in maintaining the ecological state of the Southern Aral Sea region. The study of hydrography, morphometry and monitoring of the current state of the lake Dzhyltyrbas enables to develop the necessary measures to preserve the flora and fauna of lake and a permanent ecosystem.

REN Bo, CAO Yongqiang, LI Kexin et al.

Water resources are important for human survival.The utilization of water resources can influence the water cycle.At the same time,as an integral part of the hydrological cycle,water resources have a restrictive effect on the natural environment and human beings.In this paper,the relevant data on water resources,society,economy,and ecology from 2010 to 2020 were sorted out,and a multi-factor evaluation system was constructed.The weights were determined by combining the analytic hierarchy process and the entropy weight method.The ideal point method and a coupling coordination model were used to evaluate the water resources carrying capacity and the coordinated development level of each subsystem in Liaoning Province.In this way,it is expected to perfect the water resources management system and promote the development of water resources.The following results were obtained from this study.① The water resources carrying capacity of Liaoning Province showed an increasing trend during 2010—2020,and the carrying capacity was evaluated as grades Ⅱ—Ⅳ.② The coupling coordination level of water resources in Liaoning Province is between 0.6 and 0.9,which is in the transition stage from primary coordination to intermediate coordination.In 2020,all prefecture-level cities showed good coordination.The coupling coordination of water resources,society,economy,and ecology is in the order of economy&gt;society&gt;ecology&gt;water resources.③ The water resources carrying capacity in Liaoning Province is mainly influenced by precipitation,sewage treatment rate,water resources volume,and the proportion of tertiary industry.In the future,we should improve water use efficiency,firmly establish the concept of green development,and realize the sustainable development of water resources.

Asif Imran, Tevfik Kosar

Software design debt aims to elucidate the rectification attempts of the present design flaws and studies the influence of those to the cost and time of the software. Design smells are a key cause of incurring design debt. Although the impact of design smells on design debt have been predominantly considered in current literature, how design smells are caused due to not following software engineering best practices require more exploration. This research provides a tool which is used for design smell detection in Java software by analyzing large volume of source codes. More specifically, 409,539 Lines of Code (LoC) and 17,760 class files of open source Java software are analyzed here. Obtained results show desirable precision values ranging from 81.01\% to 93.43\%. Based on the output of the tool, a study is conducted to relate the cause of the detected design smells to two software engineering challenges namely "irregular team meetings" and "scope creep". As a result, the gained information will provide insight to the software engineers to take necessary steps of design remediation actions.

Shuyu Y Chang, Zahra Ghahremani, Laura Manuel et al.

Hydraulic geometry parameters describing river hydrogeomorphic is important for flood forecasting. Although well-established, power-law hydraulic geometry curves have been widely used to understand riverine systems and mapping flooding inundation worldwide for the past 70 years, we have become increasingly aware of the limitations of these approaches. In the present study, we have moved beyond these traditional power-law relationships for river geometry, testing the ability of machine-learning models to provide improved predictions of river width and depth. For this work, we have used an unprecedentedly large river measurement dataset (HYDRoSWOT) as well as a suite of watershed predictor data to develop novel data-driven approaches to better estimate river geometries over the contiguous United States (CONUS). Our Random Forest, XGBoost, and neural network models out-performed the traditional, regionalized power law-based hydraulic geometry equations for both width and depth, providing R-squared values of as high as 0.75 for width and as high as 0.67 for depth, compared with R-squared values of 0.57 for width and 0.18 for depth from the regional hydraulic geometry equations. Our results also show diverse performance outcomes across stream orders and geographical regions for the different machine-learning models, demonstrating the value of using multi-model approaches to maximize the predictability of river geometry. The developed models have been used to create the newly publicly available STREAM-geo dataset, which provides river width, depth, width/depth ratio, and river and stream surface area (%RSSA) for nearly 2.7 million NHDPlus stream reaches across the rivers and streams across the contiguous US.

Shavindra Wickramathilaka, Ingo Mueller

One of the main reasons that cause seniors to face accessibility barriers when trying to use software applications is that the age-related user interface (UI) needs of seniors (e.g., physical and cognitive limitations) are not properly addressed in software user interfaces. The existing literature proposes model-driven engineering based UI adaptations as a prominent solution for this phenomenon. But in our exploration into the domain, we identified that the existing work lacks comprehensiveness when it comes to integrating accessibility into software modelling tools and methods when compared to a well-recognised accessibility standard such as the Web Content Accessibility Guidelines (WCAG). Thus in this paper, we outline a research roadmap that aims to use WCAG as a reference framework to design domain-specific languages that model the diverse accessibility scenarios of senior users via user context information and UI adaptation rules modelling so that they meet the accessibility standards specified in WCAG.

Patrick Chadbourne, Nasir Eisty

Causal inference is a study of causal relationships between events and the statistical study of inferring these relationships through interventions and other statistical techniques. Causal reasoning is any line of work toward determining causal relationships, including causal inference. This paper explores the relationship between causal reasoning and various fields of software engineering. This paper aims to uncover which software engineering fields are currently benefiting from the study of causal inference and causal reasoning, as well as which aspects of various problems are best addressed using this methodology. With this information, this paper also aims to find future subjects and fields that would benefit from this form of reasoning and to provide that information to future researchers. This paper follows a systematic literature review, including; the formulation of a search query, inclusion and exclusion criteria of the search results, clarifying questions answered by the found literature, and synthesizing the results from the literature review. Through close examination of the 45 found papers relevant to the research questions, it was revealed that the majority of causal reasoning as related to software engineering is related to testing through root cause localization. Furthermore, most causal reasoning is done informally through an exploratory process of forming a Causality Graph as opposed to strict statistical analysis or introduction of interventions. Finally, causal reasoning is also used as a justification for many tools intended to make the software more human-readable by providing additional causal information to logging processes or modeling languages.

P. Maurya, F.E. Christensen, M. A. Kass et al.

Abstract. Imaging geological layers beneath lakes, rivers, and shallow seawater provides detailed information critical for hydrological modeling, geologic studies, contaminant mapping, and more. However, significant engineering and interpretation challenges have limited the applications, preventing widespread adoption in aquatic environments. We have developed a towed transient electromagnetic (tTEM) system for a new, easily configurable floating, transient electromagnetic instrument (FloaTEM) capable of imaging the subsurface beneath both freshwater and saltwater. Based on the terrestrial tTEM instrument, the FloaTEM system utilizes a similar philosophy of a lightweight towed transmitter with a trailing offset receiver pulled by a small boat. The FloaTEM system is tailored to the specific freshwater or saltwater application as necessary, allowing investigations down to 100 m in freshwater environments and up to 20 m on saline waters. Through synthetic analysis, we show how the depth of investigation of the FloaTEM system greatly depends on the resistivity and thickness of the water column. The system has been successfully deployed in Denmark for a variety of hydrologic investigations, improving the ability to understand and model processes beneath water bodies. We present two freshwater applications and a saltwater application. Imaging results reveal significant heterogeneities in the sediment types below the freshwater lakes. The saline water example demonstrates that the system is capable of identifying and distinguishing clay and sand layers below the saline water column.

Wenjia Wang, Zhongjing Wang

We adopted a spectral clustering algorithm to divide the document co-citation network of 1,776 papers in the field of Lancang-Mekong water, and 14 clusters were identified. For each cluster, the top-cited references construct the knowledge base, and the most-coverage cities are taken as the research frontier. Three indicators, namely betweenness centrality, citation burstness strength, and Sigma, were used to identify the research outputs with pioneering and transformative value. The changes in the research topics and hotspots are closely related to the planning, construction, and operation progress of hydropower engineering, that affected by the gaming results of all parties. The 2009–2010 is an important time boundary, with the original research hotspots including the impact of upstream reservoirs on the hydrological regime and sediment (Clu#3) and arsenic contamination of groundwater in the Lower Mekong (Clu#4) that obtained periodical achievements and reached consensus to some extent around 2008, and the new research boom turns to the Tonle Sap Lake and flood pulse (Clu#2) in short-term characterized literatures with the highest burstness strength mainly concentrated around 2012. HIGHLIGHTS The intellectual bases and research frontiers of 14 identified topics were analyzed based on Document Co-citation Network analysis.; Vietnamese Mekong Delta is the topic with the largest size and arsenic contamination is the cluster with the longest time span.; Evolution of research hotspots is related to the widespread controversy over the planned dams in the Lower Mekong mainstream and the progress of the multi-party games.;

Ryo Miyashita, Yoshihiko Susuki, Atsushi Ishigame

Control of warm-water supply for dialysis treatment in a hospital environment is typical of safety-critical control problems. In order to guarantee the continuity of warm-water supply satisfying physical specifications for a wide range of operating conditions, it is inevitable to consider the nonlinearity involved in a dynamic model of a warm-water supply system for the control design. In this paper, we propose to incorporate control specifications described by signal temporal logic, which is a temporal logic with semantics over finite-time signals in formal methods, into the so-called Koopman-Model Predictive Control (MPC) as a novel technique of nonlinear MPC based on the Koopman operator framework for nonlinear systems. This enables us to generate a sequence of optimal inputs such that the controlled state of a nonlinear system can satisfy the specifications. The proposal is applied to the temperature regulation of warm-water supply, and its effectiveness is established numerically.

Aljosha Köcher, Alexander Hayward, Alexander Fay

Today's production systems are complex networks of cyber-physical systems which combine mechanical and electronic parts with software and networking capabilities. To the inherent complexity of such systems additional complexity arises from the context in which these systems operate. Manufacturing companies need to be able to adapt their production to ever changing customer demands as well as decreasing lot sizes. Engineering such systems, which need to be combined and reconfigured into different networks under changing conditions, requires engineering methods to carefully design them for possible future uses. Such engineering methods need to preserve the flexibility of functions into runtime, so that reconfiguring machines can be done with as little effort as possible. In this paper we present a model-based approach that is focused on machine functions and allows to methodically develop system functionalities for changing system networks. These functions are implemented as so-called skills using automated code-generation.

Andriy Miranskyy, Mushahid Khan, Jean Paul Latyr Faye et al.

Quantum computers (QCs) are maturing. When QCs are powerful enough, they may be able to handle problems in chemistry, physics, and finance that are not classically solvable. However, the applicability of quantum algorithms to speed up Software Engineering (SE) tasks has not been explored. We examine eight groups of quantum algorithms that may accelerate SE tasks across the different phases of SE and sketch potential opportunities and challenges.

Xiyuan Zeng, Annalisa Bracco, Filippos Tagklis

Near the ocean surface, river plumes influence stratification, buoyancy and transport of tracers, nutrients and pollutants. The extent to which river plumes influence the overall circulation, however, is generally poorly constrained. This work focuses on the South China Sea (SCS) and quantifies the dynamical impacts of the Mekong River plume, which is bound to significantly change in strength and seasonality in the next 20 years if the construction of over hundred dams moves ahead as planned. The dynamic impact of the freshwater fluxes on the SCS circulation are quantified by comparing submesoscale permitting and mesoscale resolving simulations with and without riverine input between 2011 and 2016. In the summer and early fall, when the Mekong discharge is at its peak, the greater stratification causes a residual mesoscale circulation through enhanced baroclinic instability. The residual circulation is shaped as an eddy train of positive and negative vorticity. Submesoscale fronts are responsible for transporting the freshwater offshore, shifting eastward the development of the residual mesoscale circulation, and further strengthening the residual eddy train in the submesoscale permitting case. Overall, the northward transport near the surface is intensified in the presence of riverine input. The significance of the mesoscale-induced and submesoscale-induced transport associated with the river plume is especially important in in the second half of the summer monsoon season, when primary productivity has a secondary maximum. Circulation changes, and therefore productivity changes, should be anticipated if human activities modify the intensity and seasonality of the Mekong River plume.

Lars Hientzsch, Christophe Lacave, Evelyne Miot

We study the asymptotic dynamics of the lake equations in the following two cases, an island shrinking to a point and an emerging island. For both cases, we derive an asymptotic lake-type equation. In the former case, the asymptotic dynamics includes an additional Dirac mass in the vorticity. The main mathematical difficulty is that the equations are singular when the water depth vanishes. We provide new uniform estimates in weighted spaces for the related stream functions which will imply the compactness result.

Aristotelis Leventidis, Laura Di Rocco, Wolfgang Gatterbauer et al.

Modern data lakes are deeply heterogeneous in the vocabulary that is used to describe data. We study a problem of disambiguation in data lakes: how can we determine if a data value occurring more than once in the lake has different meanings and is therefore a homograph? While word and entity disambiguation have been well studied in computational linguistics, data management and data science, we show that data lakes provide a new opportunity for disambiguation of data values since they represent a massive network of interconnected values. We investigate to what extent this network can be used to disambiguate values. DomainNet uses network-centrality measures on a bipartite graph whose nodes represent values and attributes to determine, without supervision, if a value is a homograph. A thorough experimental evaluation demonstrates that state-of-the-art techniques in domain discovery cannot be re-purposed to compete with our method. Specifically, using a domain discovery method to identify homographs has a precision and a recall of 38% versus 69% with our method on a synthetic benchmark. By applying a network-centrality measure to our graph representation, DomainNet achieves a good separation between homographs and data values with a unique meaning. On a real data lake our top-200 precision is 89%.

Pengfei Liu, Sabine Loudcher, Jérôme Darmont et al.

With new emerging technologies, such as satellites and drones, archaeologists collect data over large areas. However, it becomes difficult to process such data in time. Archaeological data also have many different formats (images, texts, sensor data) and can be structured, semi-structured and unstructured. Such variety makes data difficult to collect, store, manage, search and analyze effectively. A few approaches have been proposed, but none of them covers the full data lifecycle nor provides an efficient data management system. Hence, we propose the use of a data lake to provide centralized data stores to host heterogeneous data, as well as tools for data quality checking, cleaning, transformation, and analysis. In this paper, we propose a generic, flexible and complete data lake architecture. Our metadata management system exploits goldMEDAL, which is the most complete metadata model currently available. Finally, we detail the concrete implementation of this architecture dedicated to an archaeological project.