Set Of Design Solutions Research Articles

The effect of the coupling radii of the elements of membrane MEMS systems on their own oscillations

The regularities of changes in the frequencies and forms of natural oscillations and the stress state of a silicon sensing element of a mechanical MEMS accelerometer system depending on changes in the radii of rounding of structural elements are considered. An increase in the natural frequencies of the system and stresses in torsion suspensions has been established with an increase in the radii of the coupling of the suspension with the frame and the inertial mass. The rounding of the shape of the suspensions in the plan leads to a decrease in natural frequencies and an increase in stresses arising from oscillatory movements. The fact of localization of high-frequency oscillation forms in the inertial mass is confirmed. A set of design solutions is recommended to control the vibration state of the MEMS accelerometer mechanical system.

Project of basin nature management of the Vorskla River within the boundaries of Prokhorovsky district

The Belgorod region, which occupies 0.2% of the country’s territory, is among the leading subjects of the Russian Federation in the production of agricultural products. The river network of the region has undergone significant changes: over the past century, its length has decreased by 35% from its original state. The noted trends in the development of degradation processes determine the need for geo-planning solutions to ensure the soil conservation organization of nature management in the Belgorod region. In the current situation, it is necessary to scientifically substantiate the transformation of agricultural landscapes into sustainable agroecosystems. At the same time, an integrated geoecological approach should be used to organize the landscape shell with a rational spatial combination of natural and economic components. This idea formed the basis of a new synthetic direction of socio-economic geography - geoplanning. The geoplanning approach will make it possible to implement the geoecological aspects of ecosystem functioning through a set of design solutions. The results of the research work on the project: certification of the natural and economic conditions of the Vorskla River basin within the boundaries of the Prokhorovsky district of the Belgorod region was carried out; measures for ecological improvement and rational economic use of river basins were developed, including measures for biologization of arable land, allocation of areas for natural self-restoration, a plan for rational economic and recreational use of water bodies was developed, optimal network of dirt roads; calculation of environmental, economic and social outcomes of the project; proposed organization of control and supervision over the progress of the project.

Project of basin nature management of the Vorskla river within the boundaries of Prokhorovsky district

Belgorod Oblast, which occupies 0.2% of the country’s territory, is among the leading subjects of the Russian Federation in terms of agricultural production. At present, about 61% of the oblast’s territory is occupied by arable land, at least half of which, to varying degrees, is eroded. High agricultural load combined with accelerated water erosion of soils has led to a significant deterioration of the resource and environmental condition of agricultural landscapes. Negative changes affected almost all components of agro-ecosystems. First of all, it affected their central component - the soil cover: as a result of long-term exploitation and increasing water erosion, the reserves of humus and mineral nutrients decreased significantly. The region’s river network has also undergone significant changes: over the last century, its length has decreased by 35% from its original state. The above trends in the development of degradation processes determine the need for geoplanning solutions to ensure the soil conservation organization of nature management in the Belgorod region. In the current situation it is necessary to scientifically justified transformation of agricultural landscapes into sustainable agro-ecosystems. In this case, it is necessary to use a comprehensive geo-ecological approach to the organization of the landscape envelope with a rational spatial combination of natural and economic components. This idea is the basis of a new synthetic direction of socio-economic geography - geoplanning. Geo-planning approach will allow to embody geo-ecological aspects of ecosystems functioning through a set of design solutions.

Multiobjective Optimization of a Hybrid PV/Wind/Battery/Diesel Generator System Integrated in Microgrid: A Case Study in Djelfa, Algeria

Hybrid Renewable Energy Sources (HRES) integrated into a microgrid (MG) are a cost-effective and convenient solution to supply energy to off-grid and rural areas in developing countries. This research paper focuses on the optimization of an HRES connected to a stand-alone microgrid system consisting of photovoltaics (PV), wind turbines (WT), batteries (BT), diesel generators (DG), and inverters to meet the energy demand of fifteen residential housing units in the city of Djelfa, Algeria. In this context, the multiobjective salp swarm algorithm (MOSSA), which is among the latest nature-inspired metaheuristic algorithms recently introduced for hybrid microgrid system (HMS) optimization, has been proposed in this paper for solving the optimization of an isolated HRES. The proposed multiobjective optimization problem takes into account the cost of energy (COE) and loss of power supply probability (LPSP) as objective functions. The proposed approach is applied to determine three design variables, which are the nominal power of photovoltaic, the number of wind turbines, and the number of battery autonomy days considering higher reliability and minimum COE. In order to perform the optimum size of HMG, MOSSA is combined with a rule-based energy management strategy (EMS). The role of EMS is the coordination of the energy flow between different system components. The effectiveness of using MOSSA in addressing the optimization issue is investigated by comparing its performance with that of the multiobjective dragonfly algorithm (MODA), multiobjective grasshopper optimization algorithm (MOGOA), and multiobjective ant lion optimizer (MOALO). The MATLAB environment is used to simulate HMS. Simulation results confirm that MOSSA achieves the optimum system size as it contributed 0.255 USD/kW h of COE and LPSP of 27.079% compared to MODA, MOGOA, and MOALO. In addition, the optimization results obtained using the proposed method provided a set of design solutions for the HMS, which will help designers select the optimal solution for the HMS.

Turbine layout optimisation for large‐scale offshore wind farms–A grid‐based method

This study presents a new turbine layout optimisation approach using a grid-based problem formulation for improved design performance and computational efficiency for industrial-scale applications. A particle swarm optimisation algorithm is employed in the wind turbine layout optimisation, in which a micro-siting function is proposed to allow solutions 50 m of deviation while maximising energy capture without compromising maritime navigation or search and rescue operations. Solutions are assessed by a wind farm model, comprising the Larsen wake model, a multiple wake effect summation method, and a rotor-effective wind speed calculation. A novel look-up function is populated by on-the-fly algorithm and is used to reduce the number of model evaluations by approximately 95%. A gigawatt scale hypothetical site is presented to test the model on a realistically complex scenario. A set of design solutions generated by the algorithm are compared to empirical designs, with the algorithm outperforming the empirical solutions by 7.55% on average, in terms of net-present-value of energy capture minus the capital cost of turbines. The numerical efficiency and design effectiveness are examined and further improvements discussed.

Design Optimization Using Game Theory

A substantial body of literature on global design optimization techniques is based on an implicit assumption that a system under optimization is designed by a perfectly centralized design team with all team members committed to a global optimum solution. This assumption enables the system engineers to minimize all the objective functions simultaneously while controlling all design decisions at the same time. Recent research suggested that this inherent assumption may need to be revisited. This paper proposes a novel framework for design optimization using game theory, which represents a design process as a normal-form game and unifies two fundamental decisions of discipline designers, namely a system-global or a discipline-local optimum solution. This paper provides a general mathematical formulation of the framework for a design process with any number of discipline designers. The framework introduces the notion of the Nash front, which is a set of design solutions consisting of the Nash equilibria derived through the reallocation of design authority between discipline designers. This paper then tests the framework on a numerical optimization case study of a Stirling micro combined heat and power plant with two discipline designers. The result indicates that for the system capital cost and the system power output the difference between global Pareto-optimum designs and the Nash front designs on average across five different scenarios of design authority allocation was 22% and 16%, correspondingly. The application of the novel framework in different fields of engineering could help to build models that are more realistic and prevent impractical technical objectives.

Improved robust design of rock wedge slopes with a new robustness measure

This paper presents a new, computationally efficient robustness measure for robust geotechnical design (RGD) faced with a lack of statistics of statistical parameters of variables, based on reliability analysis of the system response. Considering the computational coupling between the new robustness measure and the reliability of the system, the existing framework of the reliability-based RGD approach is simplified. To illustrate the simplified and improved RGD approach, the design of rock wedge slopes is considered herein as an example. For the robust design of rock wedge slopes with combined failure modes, an N-dimensional equivalent method is adopted to ensure the feasibility and accuracy. Taking design robustness and cost efficiency as two objectives, robust design optimization is conducted while the design constraint (safety requirement) is enforced. The robust design optimization yields a set of design solutions rather than a single best solution because of the conflicting relationship between the two objectives. Based on the developed Pareto front, the most preferred designs can be specified. This design approach is illustrated through the design example of a rock wedge slope, and compared with the most preferred designs of reliability-based design (RBD), some suggestions of this robust design approach in geological engineering are presented.

Ready-to-Fabricate RF Circuit Synthesis Using a Layout- and Variability-Aware Optimization-Based Methodology

In this paper, physical implementations and measurement results are presented for several Voltage Controlled Oscillators that were designed using a fully-automated, layout- and variability-aware optimization-based methodology. The methodology uses a highly accurate model, based on machine-learning techniques, to characterize inductors, and a multi-objective optimization algorithm to achieve a Pareto-optimal front containing optimal circuit designs offering different performance trade-offs. The final outcome of the proposed methodology is a set of design solutions (with their GDSII description available and ready-to-fabricate) that need no further designer intervention. Two key elements of the proposed methodology are the use of an optimization algorithm linked to an off-the-shelf simulator and an inductor model that yield EM-like accuracy but with much shorter evaluation times. Furthermore, the methodology guarantees the same high level of robustness against layout parasitics and variability that an expert designer would achieve with the verification tools at his/her disposal. The methodology is technology-independent and can be used for the design of radio frequency circuits. The results are validated with experimental measurements on a physical prototype.

The development of knowledge-shelf to enable an effective set-based concurrent engineering application

This paper presents the development of knowledge-shelf (K-shelf) concept to enable set-based concurrent engineering (SBCE) application via knowledge provision. Three main outcomes are presented: 1) concept of the K-shelf in supporting designers throughout SBCE process; 2) demonstrates the concept via web-based software; 3) an industrial case study of surface jet pump (SJP) is also presented to validate the K-shelf concept and its software demonstrator. The K-shelf capabilities of capturing and storing design rationale in a well-structured manner and to support the comparisons among set of design solutions are the main focus of this paper.

Creating Knowledge Environment during Lean Product Development Process of Jet Engine

Organizations invest intense resources in their product development processes. This paper aims to create a knowledge environment using trade-off curves during the early stages of the set-based concurrent engineering (SBCE) process of an aircraft jet engine for a reduced noise level at takeoff. Data is collected from a range of products in the same family as the jet engine. Knowledge-based trade-off curves are used as a methodology to create and visualize knowledge from the collected data. Findings showed that this method provides designers with enough confidence to identify a set of design solutions during the SBCE applications.

К ВОПРОСУ ИСПОЛЬЗОВАНИЯ МИКРОГИДРОЭЛЕКТРОСТАНЦИЙ ДЛЯ ЦЕЛЕЙ ОРОШЕНИЯ

Purpose: to assess the technological and regulatory and technical capabilities of developing and applying power supply complexes using the energy of water flow, in relation to Russian standards to meet the electricity needs of decentralized reclamation (irrigation) systems. Materials and methods. Scientific and technical materials of Russian and foreign authors, as well as the regulatory and technical base of the Russian Federation were used as the initial data. The information processing methods were comparison, analogy, classification and systematization. Results and discussion. Among various design features of the hydropower equipment under consideration, capable of meeting local needs for electricity and at the same time having the ability to combine with elements of an irrigation network (based on relative dimensions, shape, efficiency, etc.), micro-hydroelectric power plants stand out: with propeller, radial axial, axial and capsule hydraulic turbine. The most effective schemes for installing hydraulic turbines are horizontal direct-flow and vertical Z-shaped ones. Analysis of the register of standards in the field of technical regulation in the sphere of hydropower showed that out of 131 standards under consideration, 106 can be partially applied to micro hydropower plants. Providing low-power hydropower facilities with standardization documentation has a priority in the direction of operation (21 %), monitoring and state control (19 %), and repair and reconstruction (19 %). Conclusions. The functioning of a micro-hydroelectric power station based on the energy of water movement provides for the use of a set of design solutions, which requires additional study in order to be linked to the elements of reclamation (irrigation) systems. The scope of the considered standardization documents can be extended to small hydropower facilities, taking into account the specific features of their operation. In this regard, there is a need for the development of scientifically grounded provisions of existing or being developed regulatory documents.

Surrogate-Based Design Optimisation Tool for Dual-Phase Fluid Driving Jet Pump Apparatus

A comparative study of four well established surrogate models used to predict the non-linear entrainment performance of a dual-phase fluid driving jet pump (JP) apparatus is performed. A JP design flow configuration comprising a dual-phase (air and water) flow driving a secondary gas-air flow, for which no one has ever provided a unique set of design solutions, is described. For the construction of the global approximations (GA), the response surface methodology (RSM), Kriging and the radial basis function artificial neural network (RBFANN), were primarily used. The stacked/ensemble models methodology was integrated in this study, to improve the predictive model results, thus providing accurate GA that facilitate the multi-variable non-linear response design optimisation. An error analysis of all four models along with a multiple model accuracy analysis of each case study were performed. The RSM, Kriging, RBFANN and stacked models formed part of the surrogate-based optimisation, having the entrainment ratio as the main objective function. Optimisation problems were solved by the interior-point algorithm and the genetic algorithm and incurred a hybrid formulation of both algorithms. A total of 60 optimisation problems were formulated and solved with all three approximation models. Results showed that the hybrid formulation having the level-2 ensemble Kriging model performed best, predicting the experimental performance results for all JP models within an error margin of less than 10 % in 90 % of the cases.

Space systems resilience optimisation under epistemic uncertainty

This paper introduces the concept of Resilience Engineering in the context of space systems design and a model of Global System Reliability and Robustness that accounts for epistemic uncertainty and imprecision. In particular, Dempster-Shafer Theory of evidence is used to model uncertainty in both system and environmental parameters. A resilience model is developed to account for the transition from functional to degraded states, and back, during the operational life and the dependency of these transitions on system level design choices and uncertainties. The resilience model is embedded in a network representation of a complex space system. This network representation, called Evidence Network Model (ENM), allows for a fast quantification of the global robustness and reliability of system. A computational optimisation algorithm is then proposed to derive design solutions that provide an optimal compromise between resilience and performance. The result is a set of design solutions that maximise the probability of a system to recover functionalities in the case of a complete or partial failure and at the same time maximises the belief in the desired target value of the performance index.

Stochastic multi-objective performance optimization of an in-stream woodchip denitrifying bioreactor

Woodchip denitrifying bioreactors (WDBs) that target filtration of nitrate from farm drainage water are gaining recognition as a tool for tackling the issue of diffuse nitrate pollution from agricultural landscapes. Whilst the hydraulic regime and concentration of nitrate in the drainage water constitute two fundamental environmental variables that determine the size of a denitrifying bioreactor, the issue of over- or under-treatment of water that might otherwise promote undesirable pollution swapping phenomena and construction costs also need to be factored into the overall design process. Conventional methods for optimizing the design of denitrifying bioreactors generally rely on deterministic models, even though many of the design parameters are not known with confidence. In this work we apply an alternative design philosophy and demonstrate how the bioreactor design process can be improved through application of stochastic methods. The design aspect of an ‘in-stream’ WDB planned for installation on a farm in New Zealand is structured as a multi-objective performance optimization problem that is solved in a stochastic framework, using freely available open source tools. Uncertainty considerations regarding values of physical parameters that govern bioreactor performance are incorporated into the assessment, from which a Pareto set of optimal designs was obtained. A 75 m long bioreactor of 1.5 m height was selected as the preferred choice from the optimal set of design solutions. Assuming a 10-year operational life, it is predicted the cost of nitrate removal by the planned denitrifying bioreactor will be NZ$9.70/kg-N (approx.US$6.60/kg-N).

Investigation of adaptive design variables bounds in dimensionality reduction for aerodynamic shape optimization

Geometric filtration with Proper Orthogonal Decomposition has been demonstrated in the last decade, promising effective in reducing the design space dimensionality for several industrial shape optimization problems. Thanks to the capability of re-ordering the data according to decreasing variance, the Proper Orthogonal Decomposition (POD) extracts and filters the basic features of the dataset so as to formulate the optimization problem into a new, shrunk design space. The paper proposes and investigates the reduction of the search hyperspace volume thanks to the application of POD to a set of design solutions in on-line optimization: in particular, the combination of a selection algorithm and the re-computation of the POD modes while the optimization is progressing is studied. A series of optimization results are shown for a two–dimensional test case by using a genetic algorithm. Both native geometry parameterization and the filtered one are used to highlight benefits and drawbacks of the proposed approach. Results show that, by employing the filtered parameterization and by properly/adaptively adjusting the bounds of the reduced design space, it is possible to achieve and even enhance the design performance attained with the native parameterization.

Heat transfer and lubrication of turboshaft motor-reducer

Turboshaft engines, as the rule, contains gear transmission unit – reducer and belong to the group of drive systems with the name motor-reducer. These are the compact and autonomous assemblies for various applications. In the case of turboshaft engine in combination with high speed reducer, arise the set of phenomenon which has to be solved. Majority of them are in relation to reducer protection of overheating and of gears and bearings failures. The article contains analysis of heat sources, heat transfer through design structure and heat taking out in order to maintain acceptable temperature level of reducer lubricant. Theoretical discussions are supported with various experimental results and testing procedures, including analytic calculations. The set of design solutions for reducer protection when reducer located in the area of hot gas flow, is the main content. The case study is innovative design of turboshaft motor-reducer with free turbine which provides flexible operation and compact design structure.

Energy-optimized versus cost-optimized design of high-performing dwellings: The case of multifamily buildings

Living in multifamily buildings is very common in Italy, and it is important to optimize the design strategies to minimize the energy demand of these buildings and their related operational costs. This is particularly important for low-income tenants and is pursued by many social housing developments where a good energy performance design is reached. In this work, a simulation-based optimization methodology that combines the use of TRNSYS with GenOpt is applied to minimize two objective functions—the annual primary energy demand and the operational energy cost—in different system technology scenarios, and to verify the differences between energy-optimized design and cost-optimized design in a Northern Italy climate. The study is performed on a typical floor of a real multifamily building for social housing. The envelope optimization demonstrates a potential reduction of the energy demand and cost for heating and cooling of more than 35%. The relationship between optimal solutions, system technology scenarios, and optimization objectives is deeply analyzed. It is possible to find a set of design solutions that is optimal for all analyzed scenarios. This provides a set of design alternatives that is close to the environmental optimum and is able to reduce low-income tenants' vulnerability.

Realizing Low-Cost Flash Memory Based Video Caching in Content Delivery Systems

To implement caching devices in content delivery systems, flash memory is preferable to hard disk drives from the performance perspective. Nevertheless, the higher bit cost of flash memory is one major obstacle for the wide real-life deployment of flash-based video caching. This paper presents a set of design solutions to address this cost issue. First, we present a flash memory error tolerance design strategy customized for video data storage, which can enable the use of lower-cost less-reliable flash memory chips for video storage. The cost challenge can also be addressed by reducing the video storage footprint through on-the-fly transcoding. However, direct transcoding suffers from a high implementation cost. We propose two design techniques that can largely reduce the transcoding complexity at minimal storage overhead in flash memory. All the developed design solutions share the common feature of cohesively exploring the characteristics of video coding and flash memory device physics. Their effectiveness has been well demonstrated through experiments with 20-nm MLC NAND flash memory chips and extensive simulations with representative video sequences.

Towards the appropriate synthesis of the four-bar linkage

Uncertainties are an inherent element in all mechanisms, arising from the manufacturing and assembly process or even from the operation of the device. In terms of synthesis routines for mechanisms, uncertainties are generally neglected since they are difficult to account for. In this work, the concept of appropriate design is utilized to develop routines that can more easily account for uncertainties in the geometrical parameters. These routines have been developed for linkages, specifically the four-bar linkage, and are capable of synthesizing the complete set of design solutions, referred to as allowable regions, for a set of desired coupler curve characteristics. The description of the desired coupler curve may contain any number of precision points and (or) trajectories. Several problems are solved in this work, including obtaining a representation of the coupler curve corresponding to a set of design parameters containing uncertainties, and synthesizing the appropriate designs for multiple descriptions of desired coupler curves. The results are quite promising and show great potential for using the appropriate design methodology for linkage synthesis.

Optimal sizing of PV/wind/diesel hybrid microgrid system using multi-objective self-adaptive differential evolution algorithm

Abstract Microgrid systems, such as solar photovoltaic (PV) power and wind energy, integrated with diesel generators are promising energy supplies and are economically feasible for current and future use in relation to increased demands for energy and depletion of conventional sources. It is thus important to optimize the size of hybrid microgrid system (HMS) components, including storage, to determine system cost and reliability. In this paper, optimal sizing of a PV/wind/diesel HMS with battery storage is conducted using the Multi-Objective Self-Adaptive Differential Evolution (MOSaDE) algorithm for the city of Yanbu, Saudi Arabia. Using the multi-objective optimization approach, the objectives are treated simultaneously and independently, thereby leading to a reduction in computational time. One of the main criteria to consider when designing and optimizing the HMS is the energy management strategy, which is required to coordinate the different units comprising the HMS. The multi-objective optimization approach is then used to analyze the Loss of Power Supply Probability (LPSP), the Cost of Electricity (COE), and the Renewable Factor (RF) in relation to HMS cost and reliability and is tested using three case studies involving differing house numbers. Results verify its application in optimizing the HMS and in its practical implementation. In addition, optimization results using the proposed approach provided a set of design solutions for the HMS, which will assist researchers and practitioners in selecting the optimal HMS configuration. Moreover, it is important to select optimally sized HMS components to ensure that all load demands are met at the minimum energy cost and high reliability.