Standard Engineering Tools Research Articles

Stochastic simulation algorithm for isotope-based dynamic flux analysis

Carbon isotope labeling method is a standard metabolic engineering tool for flux quantification in living cells. To cope with the high dimensionality of isotope labeling systems, diverse algorithms have been developed to reduce the number of variables or operations in metabolic flux analysis (MFA), but lacks generalizability to non-stationary metabolic conditions. In this study, we present a stochastic simulation algorithm (SSA) derived from the chemical master equation of the isotope labeling system. This algorithm allows to compute the time evolution of isotopomer concentrations in non-stationary conditions, with the valuable property that computational time does not scale with the number of isotopomers. The efficiency and limitations of the algorithm is benchmarked for the forward and inverse problems of 13C-DMFA in the pentose phosphate pathways, and is compared with EMU-based methods for NMFA and MFA including the central carbon metabolism. Overall, SSA constitutes an alternative class to deterministic approaches for metabolic flux analysis that is well adapted to comprehensive dataset including parallel labeling experiments, and whose limitations associated to the sampling size can be overcome by using Monte Carlo sampling approaches.

Combining Innovative Technology and Context based Approaches in Teaching Software Engineering

Sustainability in learning is very essential for a sustainable future which largely depends on education. Sustainable learning requires learners to increase and rebuild base-knowledge as the circumstances change and get more complex. This becomes very obvious particularly for in- formation technology (IT) discipline where technology is rapidly changing and practice getting more complicated. Sustainability enables students to use their learning from formal education into practice, provide hands on experience (HOE) and help them rebuild their knowledge base in complex situations. This is also essential to achieve a high graduate outcome rate (GOR) which helps the education sector to become sustainable. In the existing policies and frameworks, institutions are moving towards more off-campus learning and less face-to-face learning. As a result, a downward trend is experienced in students’ engagement across IT discipline. This affects students’ ability in achieving HOE and appears to be one of the reasons of low GOR which poses a threat to the sustainability in the education sector for both stakeholder and learners’ perspectives. This paper presents a combined approach of context-based teaching with incorporation of innovative technology to engage students and achieve a better HOE towards sustainability in learning. The proposed approach was adopted in a software engineering course taught at School of IT at Deakin University, Australia. Students were provided context-based teaching material and industry standard software engineering tools for practice to achieve HOE. Students evaluation and assessment results reports that proposed approach was significantly impacted positively to engage the students in classes towards improved sustainable learning.

IO-Link Wireless enhanced factory automation communication for Industry 4.0 applications

Abstract. In the context of the Industry 4.0 initiative, Cyber-Physical Production Systems (CPPS) or Cyber Manufacturing Systems (CMS) can be characterized as advanced networked mechatronic production systems gaining their added value by interaction with the ambient Industrial Internet of Things (IIoT). In this context appropriate communication technologies and standards play a vital role to realize the manifold potential improvements in the production process. One of these standards is IO-Link. In 2016 more than 5 million IO-Link nodes have been produced and delivered, still gaining increasing acceptance for the communication between sensors, actuators and the control level. The steadily increasing demand for more flexibility in automation solutions can be fulfilled using wireless technologies. With the wireless extension for the IO-Link standard, which will be presented in this article, maximum cycle times of 5 ms can be achieved with a probability that this limit will be exceeded to be at maximum one part per billion. Also roaming capabilities, wireless coexistence mechanisms and the possibility to include battery-powered or energy-harvesting sensors with very limited energy resources in the realtime network were defined. For system planning, setup, operation and maintenance, the standard engineering tools of IO-Link can be employed so that the backward compatibility with wired IO-Link solutions can be guaranteed. Interoperability between manufacturers is a key requirement for any communication standard, thus a procedure for IO-Link Wireless testing is also suggested.

Simulation of Reacting Moving Granular Material in Furnaces and Boilers An Overview on the Capabilities Of the Discrete Element Method

A brief overview is given on the capabilities and on the current limitations of the Discrete Element Method (DEM) coupled with Computational Fluid Mechanics (CFD) to simulate chemical reacting moving granular material. An approach to resolve the internal transport and reaction phenomena in particles of complex geometry is presented. Heat and mass transfer from and to the particles are accounted for as well as heat transfer between particles and between particles and a surrounding gas phase including radiation. Gas phase reactions outside the particle interact with inner particle processes.Examples will be shown to demonstrate the capabilities of DEM/CFD coupling. These examples are an industrial scale lime shaft kilns, the simulation of a domestic pellet stove and a grate firing system for the incineration of municipal waste. The advantages of a DEM/CFD approach will be highlighted but also the still existing drawbacks and limitations are discussed. The paper ends with an outlook on necessary developments to make DEM/CFD a standard engineering tool for chemically reacting granular material.

Long-term prediction of combined wave and whipping bending moments of container ships

The purpose of this paper is to propose a practical computational procedure for the long-term distribution of combined wave and whipping bending moments (BMs) of container ships. The problem is formulated in the frequency domain using standard engineering tools for load computation: a seakeeping code for the rigid-body response and a beam finite element model for transient vibratory response. The von Karman approach with correction for pile-up effect is employed for bow flare slamming load assessment. Correlation between wave and whipping BMs is considered. The procedure is demonstrated on the example of a 9200 TEU container ship. Long-term distributions of combined BMs are computed using the standard International Association of Classification Societies scatter diagram for the North Atlantic environment and two additional scatter diagrams for common shipping routes of container ships. The speed profile required for the long-term load prediction is calculated by the seakeeping analysis respecting operability limiting criteria. Conclusions about influence of various environmental and operability parameters are drawn.

LibMoM : a library for stochastic simulations in engineering using statistical moments

Stochastic simulations are becoming increasingly important in numerous engineering applications. The solution to the governing equations are complicated due to the high-dimensional spaces and the presence of randomness. In this paper we present libMoM(http://libmom.sourceforge.net), a software library to solve various types of Stochastic Differential Equations (SDE) as well as estimate statistical distributions from the moments. The library provides a suite of tools to solve various SDEs using the method of moments (MoM) as well as estimate statistical distributions from the moments using moment matching algorithms. For a large class of problems, MoM provide efficient solutions compared with other stochastic simulation techniques such as Monte Carlo (MC). In the physical sciences, the moments of the distribution are usually the primary quantities of interest. The library enables the solution of moment equations derived from a variety of SDEs, with closure using non-standard Gaussian quadrature. In engineering risk assessment and decision making, statistical distributions are required. The library implements tools for fitting the Generalized Lambda Distribution (GLD) with the given moments. The objectives of this paper are (1) to briefly outline the theory behind moment methods for solving SDEs/estimation of statistical distributions; (2) describe the organization of the software and user interfaces; (3) discuss use of standard software engineering tools for regression testing, aid collaboration, distribution and further development. A number of representative examples of the use of libMoMin various engineering applications are presented and future areas of research are discussed.

Characteristics of refrigeration systems — extension of the graphical—analytical method

Several different system balance methods and programmes have been developed and used for decades in the refrigeration industry to design refrigeration circuits and components. One of the oldest methods is the graphical—analytical method, developed and used long before computers and even calculators became standard engineering tools. The method is relatively easy and it helps to design and choose proper components. It can be successfully used today in the computer age for a better understanding of the refrigeration system behaviour, enabling the designer to see and evaluate major components, system characteristics, and system trends. This article will introduce the graphical—analytical method for the simplest refrigeration systems and later extend it to more complex refrigeration systems.

3D NEGF quantum transport simulator for modeling ballistic transport in nano FinFETs

Quantum effects play a dominant role in many of the state-of-the-art small size structures for which the applicability of the standard well-developed engineering tools based on a semi-classical transport description is very limited or even impossible. There are a number of methods developed by solid state theorists over the last several decades to address the issue of quantum transport. Among the most commonly used in nanostructure calculations schemes are the Wigner-function approach, the Pauli master equation, and the non-equilibrium Green's functions (NEGF). The growing popularity of the latest (sometimes referred to as the Keldysh or the Kadanoff-Baym) formalism is conditioned by its sound conceptual basis for the development of the new class of quantum transport simulators. We demonstrate in this work that the key to the successful application of the NEGF formalism to the 3D quantum transport problem in semiconductor nanostructures is the numerical efficiency of the contact block reduction (CBR) method. We also present some very important results from the 3D FinFET analysis, such as the importance of the third gate.

From Real-Time Data to Production Optimization

Summary A new way of reservoir management is dawning on the horizon: intelligent-reservoir management using continuous data from intelligent wells and/or smart fields. Even though there are many different buzz words for this new technology, they all lead to the same thing—managing a reservoir in real time or close to real time. Real time usually means reacting to an event as it happens or within a short time lag. In the petroleum industry, however, real time is different. This short time lag can be hours, days, or even weeks, which highly depends, of course, on the objective of a project. Integrating real-time data into a reservoir-management workflow, and turning the data into value, is a complicated task. The bottleneck for the data flow, right now, is the transfer of the realtime data, measured with time increments by the second and/or minute and stored on a real-time server, to the engineers' desktops in a clean, timely, and useful fashion. This paper shows ways to provide a continuous (i.e., 24-hours-a-day/7-days-a-week) flow of clean data to the engineers' desktops as a first step in the intelligent-reservoir management. It shows that the implementation of a smart field rises or falls with its ability to provide the data to the information specialist—the petroleum engineer. Because the data are coming into the database very frequently (e.g., at times, every hour or every other day), the engineer is not able to check these data for discrepancies. Therefore, intelligent-reservoir management needs an alarm system that informs the engineers of any underperformance or critical condition of a well or a reservoir. Another important aspect to the intelligent-reservoir management system is the integration of the standard petroleum engineering tools [e.g., decline-curve analysis, material balance, inflow performance relationship (IPR) curves, and reservoir simulation] into this work process. Currently, an IPR curve not only gets data every other month but every other day. This gives the engineer completely new opportunities for closer observation of the workflow (e.g., monitoring the permeability impairment over time). Well tests are usually a snapshot in time, but with continuous surveillance of the reservoir parameters, the development of the skin, for example, can be followed over time and preventative actions can be taken (i.e., predictive maintenance). Neural networks and genetic algorithms are other powerful tools in the real-time environment for handling large amounts of data. A neural network learns from the data gathered and detects underlying relationships—the more data, the better the network can detect these relationships. Once the underlying relationships have been established, the neural networks can be used for predictions (predictive data mining) such as predicting sand production. This approach gives the engineer time to react and prevents the equipment from getting damaged. This work provides a straightforward way of integrating realtime data into a reservoir-management process, and its methodology implies how to gain value from the information provided by a continuous data stream.

Constructing a query-able radial basis function artificial neural network.

Artificial neural networks will be more widely accepted as standard engineering tools if their reasoning process can be made less opaque. This paper describes NetQuery, an explanation mechanism that extracts meaningful explanations from trained Radial Basis Function (RBF) networks. RBF networks are well suited for explanation generation because they contain a set of locally tuned units. Standard RBF networks are modified to identify dependencies between the inputs, to be sparsely connected, and to have an easily interpretable output layer. Given these modifications, the network architecture can be used to extract "Why?" and "Why not?" explanations from the network in terms of excitatory and inhibitory in-puts and their linear relationships, greatly simplified by a run-time pruning algorithm. These query results are validated by creating an expert system based on the explanations. NetQuery is also able to inform a user about a possible change in category for a given pattern by responding to a "How can I...?" query. This kind of query is extremely useful when analyzing the quality of a pattern set.

New 'scope tools boost circuit design

Oscilloscopes and computers, today's standard engineering tools for design and troubleshooting, continue to make huge strides in capability and speed. During the last 30 years, the typical engineer's computing tool has changed from the slide rule to a microprocessor-based system running at 50 MHz or faster. The computer system's hardware and software components continue to improve substantially on an annual basis. Similarly, the troubleshooting tool for inspecting electronic signals has changed from the basic analog oscilloscope to the 500 MHz digital scope. The software and hardware in these scopes also changes dramatically on an annual basis. Some of the newest digital scopes allow the owner to upgrade the processor, add more processing RAM, increase data acquisition memory, and add storage devices such as a PCMCIA memory cards or portable hard drives. This article addresses the changes in oscilloscopes that make them more powerful tools for designing semiconductor devices and higher level circuits containing many devices.

Automated fine grid technique for measurement of large-strain deformation maps

The fine grid technique has been a standard engineering tool for measuring large strains for many years. The sample surface is marked with a grid, and the deformation of this grid allows the deformation of the sample to be monitored. However, it has never been easy quantitatively to analyse the strain across the whole of a specimen's surface. We describe here an automated approach in which digitised images of a sample prepared with a grid are analysed by the Fourier transform method. This provides phase maps which, when unwrapped, yield planes representing the two in-plane specimen coordinates. An iterative technique follows these deforming planes from one frame to the next as the specimen deforms, allowing displacement fields to be calculated. Numerical differentiation gives strains across the specimen surface. Gerchberg iteration is used to provide immunity to errors resulting from holes or tears in the specimen surface. The method is demonstrated on a propellant simulant containing burn holes (a cylinder of diameter 10 mm; grid pitch = 76 μm), loaded in compression across a diameter. All in-plane components of strain are calculated up to strains of approximately one-third. Displacement accuracy is of order 1 μm.

Why Do Engineers Wear Black Hats?

Engineers often consider their foremost responsibility to serve the public good, seeing themselves as the translators of science to technology for the benefit of the public. Yet, engineers often find themselves as the villains in public/private conflicts. The public sees engineers as the despoilers of the environment, the diligent destroyers, the tools of the establishment. This image confuses engineers who believe that they perform the function for which they were educated and for which there is public demand. The present paper suggests that the confusion is the result of differing philosophical outlooks between the engineers and the public at large. The majority of the public believes that standard engineering tools such as cost/benefit analyses are unethical, whereas the engineers believe that these techniques allow for the most fair distribution of benefit and cost. The engineering codes of ethics are a mirror of the engineers' utilitarian nature, and promote this paternalistic nature of engineering. ...

Audible pedestrian traffic signals : Part 2. Analysis of sounds emitted

This project evaluated audible pedestrian traffic signals from three perspectives: 1) the patterns of use and the impact of these signals on pedestrian travel; 2) the physical characteristics of the sound emitted by these devices; and, 3) the detection of their emitted sounds in the presence of various traffic noise levels. This paper, the second of three companion articles (2, 3), examines the sounds emitted by the Nagoya/Traconex audible traffic signal, the unit most commonly found in the western United States and almost exclusively in California. The sounds emitted by the north-south and east-west Traconex audible signals were analyzed for their loudness, directionality, frequency spectrum, and temporal characteristics using standard engineering tools including an anechoic chamber, sound level meters, spectrum analyzers, and signal analyzers.

The future of software standardization hopes and fears, an essay

The abstract and flexible nature of software poses special problems as far as standardization is concerned. The development of standard software engineering (CASE) tools may help in this, but the future offers both dangers and opportunities. Dangers lie in divergence between US and European standards, in tensions between suppliers and users, and the use of options as an easy way out. Opportunities arise in the increasingly influence of European harmonisation, in heightened awareness of the need for internationalisation, and in greater professionalism. It is suggested that the establishment of an IT Standards Research Institute would be beneficial.

Measurement and Modeling of Pacific AC Intertie Response to Random Load Switching

In recent years spectral analysis of system response to random load changes has become a standard engineering tool at the Bonneville Power Administration. Analysis of random fluctuations in power on the Pacific AC Intertie has provided information about the influence of system operating conditions upon the effectiveness of Pacific HVDC Intertie modulation, and about dynamic behavior of the western power system generally. This technique has also been used to estimate the required size for a superconducting electromagnetic storage device which will provide backup to HVDC Modulation, and has detected a major system mode 6 months before it was first observed in a transient disturbance

Nuclear excavation: review and analysis

Nuclear excavation appears to be an economical, practical and beneficial utilization of nuclear explosives. However, up to the present time, the technical, political and psychological implications of this application have presented a formidable barrier to its general acceptance. Nuclear cratering technology has been developed to the point where meaningful predictions of crater and channel sizes in selected media can be made with confidence. Continuing research is underway to extend basic cratering knowledge to saturated, fine-grained, and stratified media. Significant advances have been made in the evaluation of the magnitude and extent of the potential safety hazards associated with an underground nuclear cratering detonation. The state of the art of nuclear excavation is such that many projects appear feasible at the present time. The most apparent applications are concerned with the excavation of harbors, reservoirs, canals, and aggregate production. Nuclear excavation techniques provide a method of alleviating potentially catastrophic situations which could result from floods, landslides, and volcanoes, where all other measures would be less effective. The development of nuclear excavation into a standard engineering tool will be determined by factors not related entirely to its technical feasibility. The various political, social, and emotional pressures involved in its use will weigh heavily in its ultimate acceptance. The success of contained underground detonations for mining applications will significantly affect the future of nuclear excavation. Recent international discussions of nuclear nonproliferation have focused worldwide attention on the potential of nuclear excavation. Its acceptance appears to be only a matter of time. Nuclear excavation will come of age after the first project has been successfully completed. How long it takes before mankind can benefit from this new engineering tool greatly depends on an international willingness to cooperate in beating this all-powerful sword into a plowshare.