Engineering Change Research Articles

Data-path aware high-level ECO synthesis

Engineering Change Order (ECO) at Register Transfer Level (RTL) has been widely investigated by researchers, but at a higher level of abstraction than RTL, it is not properly addressed. Applying ECO using conventional HLS tools may result in a heavily different RTL in comparison with the original one. In order to minimize this difference, we have proposed a new high-level synthesis methodology, which considers the resulting data-path and its difference from the original one during scheduling and binding of the operations. Experimental results show that our proposed methodology makes only 6.9% changes in the connections of the original data-path in contrast to existing HLS tools, which alter 25.16% of the connections on average. Our methodology exploits 66% less spare cells than the existing HLS tools and makes no change in functional units and registers.

Aggregate risk of reactive nitrogen under anthropogenic disturbance in the Pearl River Delta urban agglomeration

Social production and consumption in highly urbanized agglomerations dramatically aggravate the creation of reactive nitrogen (Nr). Excess Nr increases the aggregate risk of air and water quality deterioration, biodiversity loss and human health impairment. The aim of this study is to assess the aggregate risk of Nr under anthropogenic disturbance based on an exposure-effect model reconciling the Nr behavior in urban environment and corresponding integrated damage impacts. In a case study of Pearl River Delta (PRD) urban agglomeration, the Nr creation and distribution were quantitatively estimated in different subsystems. The various ecosystem service and human benefit losses related to Nr accumulation pressure were classified and quantified though damage costs obtained from literature. The results showed that anthropogenic disturbance dramatically changed the Nr creation and accumulation in this urban agglomeration compared with the average level for all of China. Anthropogenic Nr creation in the PRD urban agglomeration was 355.70 Gg, and total Nr accumulation in all subsystems was 607.05 Gg in 2010. With high industrialization and urbanization, Nr tended to flow into the atmosphere and water to generate risk rather than into the land. The damage impacts of Nr in the PRD urban agglomeration centered on human health impairment (40.97%), fuel and fiber production loss (23.55%), climate and air quality decline (22.41%). To harmonize the relationship between risk management and human economic drivers, sustainable human activity changes in vehicle use, denitrification engineering and nitrogen use efficiency are suggested.

МЕТОД ПОПЕРЕДНЬОГО ФОРМУВАННЯ ОСНОВНИХ ПАРАМЕТРІВ ПІД ЧАС ГЛИБОКИХ МОДІФІКАЦІЙНИХ ЗМІН У ЛІТАКАХ ТРАНСПОРТНОЇ КАТЕГОРІЇ

The method of a preliminary development of main performances during deep variation in variants of a transport category aircraft, that is, when changing a wing area and a powerplant output, has been proposed. The main performance of any aircraft on the stage of its modifying is takeoff mass to, its value depends on structural members’ masses, in which modifications changes are present. The method is based on the com-parative evaluation of take-off mass increments of a basic aircraft and it’s variant. That allows qualitatively and quantitatively to evaluate the specific value of the take-off mass increment of an airplane variant depending on engineering and economical requirements changes. Also, it is obvious that changes in the combination of performances their changes in the process of an aircraft variant creation, move the solution of an existence equation at new point, which corresponds to a new takeoff mass. The analysis of the method was implemented on the example of the regional passenger aircraft variant with two turboprop engines. The method of a preliminary development of main performances of a transport category aircraft subject to deep modification, i.e. when changing a wing area or a powerplant output, is proposed. The mathematical model for the estimation of the takeoff mass increment, depending on requirement groups realized in modifications, is developed by using the models of calculation of required mass (due to change of modification) and available mass (constant for a base variant). Statistical equations for the preliminary estimation of a takeoff mass increment, that create the relationship between the constituent masses and the takeoff mass for a regional aircraft, are used. For middle-range and long-range airplanes an adjustment is needed. The proposed method and the mathematical models allow at a preliminary designing stage of an airplane variant not only typical required quantitative change in structure, but the necessary changes of a wing area and a powerplant output to satisfy the required engineering and economical requirements, which aircraft and air-lines’ markets dictate.

Resource-constrained scheduling of design changes based on simulation of change propagation process in the complex engineering design

When resource constraints are taken into consideration in the deployment of engineering changes, assignments of resources and changes to design entities and selection of change propagation paths make the scheduling problem difficult to solve. Due to complicated dependency relations between engineering entities in the complex engineering design process making it difficult to build an explicit objective function to evaluate different change propagation paths, an integrated simulation and optimization approach is adopted in this research to identify the optimal change scheduling plans for renewable resource-constrained change propagations. First, a digraph model is built to represent the product structure or design process connected with input and output logical relations; second, mathematic formulations of change scheduling problems in two kinds of resource usage schemes are presented; third, a forward-propagate-later-rollback strategy is adopted to develop the resource-constrained change propagation simulation algorithms; fourth, simulation results are used to evaluate individuals in genetic algorithm (GA) during the optimization of propagation likelihood for each involved design dependency. Two case studies are conducted to demonstrate the effectiveness of the models and methods developed in this research. Results for both resource usage schemes are compared, and it can be found that: (1) shorter-duration change propagation plans can be found in the dedicated resource usage scheme than in the flexible scheme; (2) the flexible resource usage scheme can produce a fairer workload allocation between design resources than the dedicated scheme; and (3) the tradeoff between change duration and cost should be determined by design delivery urgency and cost budget in addition to choosing an optimal change propagation plan.

Changes in Marine Diesel Engines Operating Strategy

Abstract Constant changes in the operating strategy of marine diesel engines are observed. They refer to whole engine and different functional systems of the engine in different range. The paper presents changes in marine diesel engines operating strategy. Gradual transition from simple failure response operating strategy – Corrective Maintenance (CM) to a reliability-oriented strategy – Reliability Centered Maintenance (RCM) has been described together with some remarks about Planed Maintenance (PM) systems and Condition Based Maintenance (CBM) systems with their latest form called CBM+. Some information about changes in diesel engines operating strategy in the Polish Navy (PN) at the turn of the last 35 years is also presented. An attempt to build engine analyzer for high-speed diesel engines at the Polish Naval Academy (PNA) in order to improve submarine diesel engines operating strategy is also described in the paper.

Evaluation of the test drive cycle conditions impact on exhaust emissions from an internal combustion engine

Test results of exhaust emission sensitivity to engine operating conditions from a vehicle with a compression ignition engine have been analyzed. These results were determined in driving tests: NEDC (New European Driving Cycle), RDE (Real Driving Emissions) and Malta, an original drive cycle developed at Poznan University of Technology. The tests in the NEDC and Malta cycles were carried out on the engine dynamometer in driving tests simulation conditions, while the RDE test was carried out in the real conditions of passenger car traffic. The mean exhaust emission test results of carbon monoxide, hydrocarbons, nitrogen oxides and carbon dioxide as well as the mean particle number in individual tests have been provided. A high sensitivity of the tested emission values to the changes in engines operating conditions was found, both for static and dynamic conditions. The strongest impact of engine operating conditions was found for hydrocarbons emissions and the number of particles, followed by carbon monoxide, a smaller impact was found for nitrogen oxides and carbon dioxide. The largest differences in the values characterizing exhaust emissions were found for the NEDC test, which differed the most in dynamic engine operating conditions from other tests that closer resemble real driving conditions of vehicles.

The factors and possible consequences of regional changes in engineering and geotechnical status of loesses and loessy-loamy soils of Ukraine

Over the recent decades in Ukraine regional activation of flooding of lands, accompanied by landslide formation and subsidence of surfaces take place. It is caused by interaction of a complex of natural and technogenic factors (global climate changes, groundwater afflux in areas of impact of reservoirs, flooding of numerous mines and quarries, etc.). On the territories of the most widespread in Ukraine loessy and loessy-loamy soils these phenomena become the most dangerous transformations of engineering and geotechnical state of the upper part of the geological environment. The researches carried out at the ITGIS have clarified that the specific engineering and geological properties of loessy soils (soaking, subsidence and thixotropy) are the main factors contributing to progressive reduction of engineering seismogeological stability of these soils. The cause of thixotropic dilution is the operation of various vibration mechanisms or closeness of the objects causing vibration (railways, etc.). Thixotropic dilution is mostly caused by vibrational destruction of non-waterproof aggregate structure of loessy soil. Destruction is also accompanied by vibrational movement of products of destruction into the pore space. After termination of vibration the aggregate structure is partially restored due to the formation of secondary aggregates.Today more than 50% of 460 cities and 885 urban-type settlements in Ukraine are located in the zone of subsiding loessy and loessy-loamy soils, up to 15% are affected by natural and technogenic karst formation, and in 9% (123) of the cases development of landslides was recorded. Natural and technogenic flooding of the territory was recorded in more than 40% (546) of cities and towns. Therefore, there are complex changes in the geotechnical conditions in majority of the industrial urban agglomerations of Ukraine and deterioration of ecological and geological parameters of life within them. The zoning by the regional geotechnical risk of flooding of cities and villages of Ukraine situated on loessy and loessy-loamy soils should be carried out on the basis of the combined effect of natural and technogenic factors. It is recommended to apply the additive model of influence on geotechnical risk. The mentioned risk is proposed to be quantified by indicators of the specific density of areas of flood and landslide development in both technogenic and natural conditions.The property of water-saturated loessy soils to move to the quicksand state is mostly due to the structural features of these soils and to the laws of their transition to the rarefied state. The process of obtaining by loesses (in circumstances of long-term flooding) of fluid-thixotropic properties develops in the Southern region on irrigated lands and begins to spread to the other regions. It is necessary to continue scientific and production works to improve the methodological basis of an assessment of the impact of modern changes in levels and chemical composition of groundwater, negative technogenic effects on the subsoil, global climate change and other factors on formation of the geotechnical risk using modern technologies of GIS and Earth remote sensing, as well as to complement this basis with ecologic, economic and insurance assessments of the risk of life safety.

Study on Strength Characteristics of Solidified Contaminated Soil under Freeze-Thaw Cycle Conditions

Cement solidification/stabilization is a commonly used method for the remediation of contaminated soils. The stability characteristics of solidified/stabilized contaminated soils under freeze-thaw cycle are very important. A series of tests, which include unconfined compressive strength tests, freeze-thaw cycle tests, and scanning electron microscopy (SEM) tests, are performed to study the variation law of strength characteristics and microstructure. It aims at revealing the microcosmic mechanism of solidified/stabilized Pb2+ contaminated soils with cement under freeze-thaw cycle. The results show that the unconfined compressive strength of the contaminated soils significantly improved with the increase of the cement content. The unconfined compressive strength of stabilized contaminated soils first increases with the increase of times of freeze-thaw cycle, and after reaching the peak, it decreases with the increase of times of freeze-thaw cycle. The results of the scanning electron microscopy tests are consistent with those of the unconfined compressive strength tests. This paper also reveals the microcosmic mechanism of the changes in engineering of the stabilized contaminated soils under freeze-thaw cycle.

For Jet Engine Wing Mounting

The mounting of a jet engine under the wing of an airliner can be a daunting task for turbofan engineers. Thrust forces generated by gas path momentum flow changes in a jet engine are transmitted by pressure (and friction) forces on stators and struts attached to the engine case. Case engine mounts then transmit the thrust forces (as high as 100,000 pounds thrust on the largest engines) to the wing pylons to pull the plane forward. The mounts must also support the engine weight (as high as 20,000 pounds) and carry nacelle flight loads. Engine bypass ratios are increasing (12:1 on the new geared fan engines), with fan sizes ever growing (178 inch diameter fan on the new GE9X). Mounting these new engines under a wing can present new challenges. During the early days of its introduction in the late 1960’s, Boeing’s iconic 747 jumbo jet had engine mount problems. These are examined, together with their solution.

Educational Challenges: Issues with Power Engineering Education [In My View

Success in science and engineering is nearly always underpinned by a robust education system that caters to teaching and research. Therefore, it is fair to say that a good, practical engineering education is the single most important factor for a nation's sustainable development and economic prosperity. This is particularly critical today as we are living through times of unprecedented social, economic, and technological change. Artificial intelligence and robotics have emerged as the next frontier of technological evolution. The electric power industry is experiencing fundamental changes brought about by the need to prodlice our electrical energy in a more sustainable manner not only in environmental terms but also in economic terms. While the basic science and engineering principles are not changing, there is no question that the underlying themes that were the staple of electric power systems engineering courses will require redevelopment and updating. This article aims to tease out some of the key drivers for change in the way engineering, and electrical power system engineering in particular, is taught.

Likelihood and cost impact of engineering change requirements for DoD contracts

Purpose There appears to be no empirical-based method in the literature for estimating if an engineering change proposal (ECP) will occur or the dollar amount incurred. This paper aims to present an empirically based approach to address this shortfall. Design/methodology/approach Using the cost assessment data enterprise database, 533 contracts were randomly selected via a stratified sampling plan to build two regression models: one to predict the likelihood of a contract experiencing an ECP and the other to determine the expected median per cent increase in baseline contract cost if an ECP was likely. Both models adopted a stepwise approach. A validation set was placed aside prior to any model building. Findings Not every contract incurs an ECP; approximately 80 per cent of the contracts in the database did not have an ECP. The likelihood of an ECP and the additional amount incurred appears to be statistically independent of acquisition phase, branch of service, commodity, contract type or any other factor except for the basic contract amount and the number of contract line item numbers; both of these later variables equally affected the contract percentage increase because of an ECP. The combined model overall bested current anecdotal approaches to ECP withhold. Originality/value This paper both serves as a published reference point for ECP withholds in the archival forum and presents an empirically based method for determining per cent ECP withhold to use.

Engineering change? The idea of ‘the scheme’ in African irrigation

Abstract Despite a growing recognition of the significance of farmer-led irrigation, externally engineered and induced schemes remain a popular model for irrigation development in sub-Saharan Africa. These have had a mixed record, and many have been widely critiqued. Nonetheless, schemes that were initiated under colonialism have been rehabilitated and new schemes are still being developed. This paper interrogates the continuing attraction of this model for irrigation, asking how and why it persists. Is the fact that engineering is so central to irrigation schemes another example of ‘high modernism’, as Scott might argue? Analysis of the history and current policy-making context of a new irrigation scheme in Malawi suggests a picture that is more complex, in which practical engineering considerations combine with narratives of modernisation and political imperatives to create momentum and lock-in. Understanding this, and why lessons from the past inadequately shape future-directed planning requires interrogation of the positionality of those involved, including state, donors and private sector actors and the political, economic and discursive fields in which they operate.

Evaluation analysis of particulate relevant emission of a diesel engine running on fossil diesel and different biofuels

Air pollutants derived from diesel engines have more and more dangerous effect on the nature and on the built environment as well. One of the most important emission-component of a diesel engine running on conventional diesel is particulate matter. For measuring particulate matter there are many different widely used measurement methods. Using biofuel in diesel engines also causes emission of particulate matter. The basic aim of our work was to investigate and to evaluate the conventional biodiesel's and the new type TBK-Biodiesel's effect on the particulate relevant emission of a compression ignition engine. Particulate relevant emission mean in this case the four different measurement methods like filter smoke number, opacity, particulate mass and particulate number. With a rising blending rate of the - in internal combustion engine useable - bio derived fuels (standardized biodiesel and non-standardized TBK-biodiesel) to fossil diesel the particulate relevant emission of the engine changes significantly. The tendencies in particulate relevant emission with growing blending rate are different among the measurement methods. Because of this situation biofuels cannot be evaluated clearly compared to fossil diesel in point of view of particulate relevant emission.

Adaptability in aerospace production using Cyberphysical Systems

Una característica en la industria automatizada son los cambios de ingeniería y problemas de producción respecto a los mantenimientos correctivos y preventivos de los robots. Esto aunado a los problemas de faltantes de material y retrasos en el arribo de componentes; repercutiendo en pérdidas de tiempo de producción, que da como resultado planes de producción muy cambiantes, perdida de dinero y un estresante modo de operación en todos los departamentos. Este artículo describe cómo los sistemas ciberfisicos, son una herramienta importante para una industria con ritmo acelerado; nuestro caso de estudio es la industria aeroespacial debido a su gran crecimiento en México. Actualmente a pesar de que se encuentran automatizadas las plantas aeroespaciales, el software que se utiliza en el proceso es independiente uno de otro, los componentes de software necesitan grados de libertad en forma de parámetros, para que puedan reaccionar a los nuevos requisitos que la industria aeroespacial requiere sin poner en riesgo la calidad.

(Invited) A Moore’s Law for Packaging and the Role of Bonding

While Silicon has scaled aggressively by over a factor of a few thousand over the last six decades the progress in packaging has been more modest – a linear factor 4-5 in most cases. In this talk, we will examine the reasons for this lag and what we are doing to fix this imbalance. Packaging is undergoing a renaissance where chip-to-chip interconnects can approach the densities of on-chip interconnects. We will discuss the technologies that are making this happen and how these can change our thinking on architecture and future manufacturing. Specifically, we will discuss two embodiments: Silicon as the next generation packaging substrate, and Flexible electronics using fan-out wafer level processing. We will highlight the role of thermal compression bonding and fusion bonding. Finally, we’ll discuss how these developments can help put some intelligence into Artificial Intelligence and bring about changes in Medical Engineering.

A multi-level 3D data registration approach for supporting reliable spatial change classification of single-pier bridges

The reliability of condition assessment of bridges using 3D imagery data, such as 3D laser scanning point clouds, relies on inspectors’ structural engineering knowledge and skills of 3D data processing. A challenge of 3D-data-based structural condition assessment lies in the difficulties of reliably comparing 3D imagery data sets collected at different times for analyzing spatial changes of the structures and finding anomalous deformations. Spatial changes of structures could occur at multiple levels of details and be of different types: (1) rigid body motions (e.g., translations and rotations) at the structure or structural element levels; (2) deformations (e.g., bending of girders) at the levels of structural elements. Unfortunately, existing 3D imagery data-based change analysis methods only produce deviations between two 3D data sets without distinguishing deviations caused by various changes at multiple levels. Significant rigid body motions of structures and structural elements often cause large deviations that “overwhelm” deviation patterns caused by smaller element-level deformations so that engineers could hardly recognize local deformations. Unreliable deformation analysis of structural elements can lead to incorrect condition assessments.This paper presents a new multi-level 3D data registration and spatial change classification approach that automate the analysis of both element-level deformations and interactions between the motions of multiple elements based on deviations calculated between two 3D data sets. This approach uses a multi-level data registration method augmented by formalized knowledge for representing spatial changes using deviation maps between two 3D datasets. This knowledge will guide pattern analysis methods to reveal how various changes of structures collectively lead to structural systems behaviors. More specifically, this 3D data registration and spatial change classification approach eliminates deviations caused by rigid body motions before assessing deformations of structural elements. The authors conducted annual 3D imagery data collection for two single pier bridges in July 2015 and June 2016, and use those 3D data to characterize the performance of the new approach in identifying relative motions between and deformations of structural elements. The results indicate that the new approach can reliably identify relative motions between and deformations of bridge elements, such as angular changes between elements, and torsions of girders. Finally, the authors validated the change analysis results generated by the developed approach against the traditional change analysis results obtained by a knowledgeable structural engineering researcher and change analyses in multiple single-pier bridge research studies.

A UAV Case Study with Set‐based Design

AbstractThe DoD and Engineered Resilient Systems (ERS) community seek to leverage the capabilities of model‐based engineering (MBE) early in the design process to improve decision making in AoAs. Traditional tradespace exploration with point‐based design often converges quickly on a solution and engineering changes are required after this selection. Set‐based design considers sets of all possible solutions and enables down‐selecting possibilities to converge at a final solution. Using an Army case study and an open source excel add‐in called SIPMath, this research develops an integrated MBE model and example that simultaneously generates numerous designs through physics models into the value and cost tradespace allowing exploration for set‐based design analysis and producing a better efficient frontier than traditional point‐based design AoAs. Grouping design decisions into sets based on their characteristic decision, and simultaneously evaluating the value and cost tradespace, allows for a set‐based design approach that provides insight into the design decisions.

Designing in young organisations: engineering change propagation in a university design project

Engineering change (EC) is an important phenomenon in the design of products and systems, accounting for nearly one-third of the work effort; however, the literature has been focused on mature firms, and few studies have documented the impact of EC beyond them. Hence, we use a case study approach to study EC and its propagation in the context of a university design project as an example of young organisations, and compare it with the existing work done on mature firms. It was found that 33% of the changes that occurred in the case study were planned, and change propagation accounted for 20% of all changes. The propagation of changes was usually one step (67%), and it was concentrated in one independent network (54%). The results were subsequently compared with EC studies done in mature firms, being revealed that EC behaves differently in the context of a university design project; hence, existing change management tools developed to suit mature firms may not be directly suitable for supporting university design projects. The findings from this work can be used as a platform to better understand how EC propagates when designing in young organisations and shape the development of appropriate change management tools.

Error propagation in computer models: analytic approaches, advantages, disadvantages and constraints

Uncertainty and its propagation in computer models has relevance in many disciplines, including hydrology, environmental engineering, ecology and climate change. Error propagation in a model results in uncertainty in prediction due to uncertainties in model inputs and parameters. Common methods for quantifying error propagation are reviewed, namely Differential Error Analysis and Monte Carlo Simulation, including underlying principles, together with a discussion on their differences, advantages and disadvantages. The separate case of uncertainty in the model calibration process is different to error propagation in a fixed model in that it is associated with a dynamic process of iterative parameter adjustment, and is compared in the context of non-linear regression and Bayesian approaches, such as Markov Chain Monte Carlo Simulation. Error propagation is investigated for a soil model representing the organic carbon depth profile and also a streamflow model using probabilistic simulation. Different sources of error are compared, including uncertainty in inputs, parameters and geometry. The results provided insights into error propagation and its computation in systems and models in general.

Selection of accelerated test modes for the head of cylinder of the automobile diesel engine

The possibilities of a prediction of the heads of cylinder durability of the automotive diesel engines at the design stage and their completion to specified parameters, especially for reliability are considered. Since diesel engines operate in the unsteady modes, the main load is not only mechanical, but also thermal. At that, it occurs when the operating modes of the diesel engine change. The most loaded sections in the cylinder head are the bridges between the inlet and exhaust valves, as well as the bridges between the nozzle holes and inlet and exhaust valves. Under the influence of the thermal load, the distortions of the crystal lattice appear in the sections of the cylinder head at first, which leads to the appearance in some direction in which the greatest tangential stresses act, tears, gradually change under the influence of alternating stresses in the crack. When the total accumulated damage reaches a certain critical value, and the crack substantially weakens the cross section, fatigue failure occurs. To ensure the reliability of the diesel engine in operation, it is necessary to choose such methods of calculation and testing that would ensure a specified durability of the cylinder head. Since the reliability check in operation takes considerable time, that accelerated testing is used to reduce the test time. The place occupied by the accelerated tests in the design of diesel engines, as well as the sequence of the formation of their program are considered. It is shown that in practice it is possible to achieve only a certain degree of change in the technical condition of the cylinder head due to the degree of completeness of the accounting of the interacting operational loads and their distortion during reproduced on the test equipment. Possible modes of testing the cylinder heads on a non-motorized thermal bench are proposed with the aim of a determination their durability. They correspond to the modes of accelerated tests for the reliability of the automobile diesel engines. The problem of convergence of the results at accelerated tests and the data under operating conditions is considered.