Experimental Design Process Research Articles

A KNOWLEDGE-BASED SYSTEM FOR STENCIL PRINTING PROCESS PLANNING AND CONTROL

ABSTRACT Surface mount technology (SMT) is one of the most important developments in electronic industry. A surface mount assembly (SMA) has three consecutive manufacturing steps: solder paste stencil printing, component placement, and solder reflow. Stencil printing process (SPP) involves highly operation complexity and has multiple quality characteristics, and averagely accounts for 60% of soldering defects in SMA. This work presents a knowledge-based system for SPP planning and control to upgrade soldering quality level and system performance. A hybrid data set contains a 38-3 experimental design and statistical process control (SPC) records was collected firstly, and followed by data processing for removing conflicted, inconsistent, and redundant samples through a fuzzycluster algorithm. The output columns of the clustered data were then transformed using fuzzy quality loss function (FQLF) with respect to the dissatisfaction of printing performance. The neuro-fuzzy technique was adapted to model and learn SPP knowledge from the transformed data set into a SPP knowledge base. Finally, a GUI man-machine interface was developed to help engineers in predicting responses and evaluating the overall SPP performance. The empirical evaluations of soldering quality and productivity demonstrate the effectiveness and efficiency of this proposed system.

Teaching simple experimental design to undergraduates: do your students understand the basics?

This article provides instructors with guidelines for teaching simple experimental design for the comparison of two treatment groups. Two designs with specific examples are discussed along with common misconceptions that undergraduate students typically bring to the experiment design process. Features of experiment design that maximize power and minimize the effects of interindividual variation, thus allowing reduction of sample sizes, are described. Classroom implementation that emphasizes student-centered learning is suggested, and thought questions, designed to help students discover and name the basic principles of simple experiment design for themselves, are included with an answer key.

Structure and Format of Peer-Reviewed Scientific Manuscripts

o t n p a n p m n the early 17th century, Sir Francis Bacon popularized the scientific method of investigation. This method of inquiry advances knowledge by structured process of experimental design, obseration, and testing of a hypothesis. Medical jourals have become the vehicle whereby investigaors present the results of their studies. At some oint, most medical professionals become involved n writing scientific manuscripts, often as physicians/ urgeons in training or as young practitioners; howver, residencies and fellowships traditionally offer ittle or no formal instruction concerning the strucure and format of a scientific article. Authors often earn the writing process simply by reading published rticles in peer-reviewed medical journals with little irection or guidance from mentors. Although readng and critiquing scientific articles can be a valuable ool for becoming a medical writer, good scientific riting requires a basic understanding of the strucure and format of peer-reviewed scientific manucripts. The purpose of this presentation is to set forth the ssential elements of a peer-reviewed scientific artile. It is anticipated that such a discussion will be of alue not only to potential authors of scientific manucripts, but also to readers of peer-reviewed journals. lthough this presentation is concerned principally ith writing for the Journal of Hand Surgery, it is elevant to medical journal writing in general. The process of writing a scientific manuscript is nalogous to telling a story. Like every well-written tory, a scientific manuscript should have a begining (Introduction), middle (Materials and Methods), nd an end (Results). The Introduction presents the opic and identifies the purpose of the study, the aterials and Methods section tells what the author id to address that purpose, and the Results section resents what was observed. The Discussion (the oral of the story) puts the study in perspective. The bstract is an opening summary of the story and he Title gives the story a name. Generally speaking, he author should first write the Introduction, Matet ials and Methods, and Results sections as a unit ecause the 3 are so entwined and interdependent. nly after these sections are written can the author ully discuss the study, accurately summarize it, and ive it an appropriate name. A clear understanding of he essential components of each of these sections is ritical to the successful composition of a scientific anuscript (Table 1).

Electrogravimagnetics: Practical Modeling Methods of the Polarizable Vacuum -- I.

A number of tools to facilitate the experimental design process are presented. These include the development of a design matrix based on the unit-amplitude spectrum and the derivation of harmonic and spectral similarity equations, critical phase variance, critical field strengths, and critical frequency.

A comparative analysis of the Taguchi and Shainin DOE techniques in an aerospace environment

Purpose – To highlight the application and to compare the effectiveness of the Taguchi and Shainin experimental design processes as applied to aerospace structural components.Design/methodology/approach – This paper applies both the Taguchi and Shainin experimental design techniques to optimizing the design of honeycomb composite joints. The techniques are fully applied, the results analysed and their user friendliness is assessed.Findings – This paper identifies an optimum parameter setting for composite joints gained from applying these experimental design techniques. Significant improvements in joint strength are achieved through identifying a new joint setting.Practical implications – The adoption of the experimental design techniques outlined in this paper and their application to a real engineering problem will enable a company to apply the techniques and to attain improvements in terms of cost and quality.Originality/value – The analysis of both the Taguchi and Shainin methodologies and the resulti...

Robust modular product family design using a modified Taguchi method

The Taguchi method is very effective in improving quality and decreasing cost while increasing the robustness of designs. However, it is an ‘open control system’ that relies on experiments to determine the optimal levels of control factors. The critical information about how the quality characteristic is affected by changes in the control factor is not considered in the experimental design process. This paper proposes a modified Taguchi methodology by introducing the feedback of quality characteristics to improve the robustness of modular product families against changes in customer requirements to efficiently determine the optimal control factors and the corresponding suitable time periods for designing robust product families. The research questions addressed in this paper include: How to efficiently optimize control factors in the design of product families? How to measure the robustness of a product family for meeting current and future needs? How far into the future should designers look in while designing a robust product family? This paper demonstrates the application of our methodology using a simplified example of a vacuum product family to determine the optimal module instances that need to be deployed in the future.

Dedicated analytical formulation for an experimental set‐up to determine thermomechanical properties ‐ sensitivity and inverse analyses

AbstractComputational analysis of new experiment is presented here. It is realized within two main tasks: 1. an application of inverse thermal analysis supported by thermovision measurements into evaluation of thermomechanical parameters of non‐homogeneous materials (like concrete), 2. an application of sensitivity analysis in a new experiment design process.

Experimental design and processing for time-reversal communications in a highly reverberant environment

A suite of experiments has recently been conducted to validate the utility of using time-reversal (T/R) theory to solve a communications problem for highly reverberant environments. This paper discusses the design and layout of those experiments as well as experimental equipment criteria and selection. Solutions to problems arising from equipment limitations encountered during the experimental design process are examined. The signal processing used to extract information from gathered data is described and it is shown that communications receivers utilizing T/R theory can be used to accurately reproduce messages broadcast through hostile, reverberant communications channels.

User studies: why, how, and when?

User studies offer a scientifically sound method to measure a visualization's performance. Reasons abound for pursuing user studies, particularly when evaluating the strengths and weaknesses of different visualization techniques. A good starting point in any study is the scientific or visual design question to be examined. This drives the process of experimental design. A poorly designed experiment will yield results of only limited value. Although a comprehensive discussion of experimental design is beyond the scope of the article, we offer suggestions and lessons learned. We also describe how we designed experiments to answer important questions from our own research.

Teaching How to Calibrate a Process Using Experimental Design and Analysis: The Ballistat

As part of the University of Newcastle's Total Quality Management (TQM) course, students study Experimental Design (ED) and Statistical Process Control (SPC) within the framework of the scientific approach to process improvement. A sufficient balance of theory and application is required to keep Business and Management students, most with a largely non-quantitative background, interested and aware of the need and method to correctly implement ED and SPC in industry. Tools to facilitate a basic understanding of the importance of the 3Rs, namely, Randomization, Replication, and Blocking, as well as highlighting the potential for mistakes or inefficient calibration techniques are essential in the learning process. This paper describes the use of a particular tool, called the “Ballistat,” to illustrate TQM concepts, which enables students to obtain the hands-on experience needed to control processes in industry.

The Effect Of Experiment Design Process On Self- Efficacy Belief Of Preservice Science Teacher In Elementary Science Education Class

Preservice teachers' self efficacy belief is considered to increase their teaching performance. The purpose of this study is to investigate how designing original experimental activities affects science teaching self efficacy beliefs among elementary teacher candidates. Sample of this study is randomly selected and assigned into two groups; as experimental and control groups (N=97). Experiemental group has designed original hands-on activities while control group has done the experiments planned beforhand by researcher. The instrument used to measure self-efficacy belief is adapted from STEBI-B and consists of 28 Likert-type items. Data analysis is carried out by deploying two-way ANOVA. The results show that preservice teachers who participate in the design of original experimental activities had significantly higher science teaching self efficacy belief scores compared to those of who have not produced original activities. Experimental group also shows more creativity in planning teaching styles, and tendency to use project-based teaching techniques. Some recommendations are made to increase preservice elementary teachers' science teaching self efficacy believes.

Use of quantitative models to design microbial transport experiments in a sandy aquifer.

A suite of numerical models was applied to the problem of designing field tracer and bacterial injection experiments in a sandy surficial aquifer near Oyster, Virginia. The models were constructed based on the integration of diverse characterization data including hydrologic, geophysical, geological, geochemical, and biological information. A one-dimensional particle-tracking model was used to analyze laboratory transport experiments conducted using intact core samples to prescribe transport parameters describing solute dispersion and bacterial fate. A geostatistical model of three-dimensional hydraulic conductivity variations was developed, conditioned on in situ measurements of hydraulic conductivity and interpretations of geophysical data, and used to generate alternative aquifer descriptions. A regional-scale, two-dimensional flow model was used to design pumping rates of a forced-gradient hydraulic control system. Information from these various models was then combined into a high-resolution, three-dimensional flow and transport model for the prediction of field-scale solute and bacterial transport. Model predictions were used in an iterative experimental design process to specify: (1) the locations of multilevel samplers for monitoring transport; (2) frequency and timing of sample collection during bromide tracer injection experiments; and (3) frequency and timing of sample collection during a bacterial injection experiment. At each stage of the design, information gained during the previous stage was used to refine the model and target subsequent experimentation.

Steady-state oxidation model by horseradish peroxidase for the estimation of the non-inactivation zone in the enzymatic removal of pentachlorophenol

A theoretical model for the rate of oxidation of pentachlorophenol (PCP) catalyzed by horseradish peroxidase (HRP), was investigated to account for the influence of hydrogen peroxide (H 2O 2) concentration on the catalytic activity. To evaluate the maximum allowable H 2O 2 concentration, a relatively simple steady-state model was developed based on the Ping-Pong Bi-Bi mechanism considering the effect of excess H 2O 2. Several sets of experimental data obtained from batch reactions using an equimolar concentration of H 2O 2 and PCP were used to estimate the kinetic parameters by a nonlinear regression method. The model profiles acquired using the estimated parameters were in good agreement with experimental data at different initial enzyme and substrate concentrations. The best-fitted parameters were used to predict the initial rate of the enzyme reaction. The model prediction was coincident with the experimental results of other studies, indicating that the proposed model could be used for the optimization of reaction conditions. The maximum allowable H 2O 2 concentration to prevent H 2O 2 inhibition was calculated from the proposed model equation: [H 2O 2] 0,max = K m H 2O 2 K i [ PCP] 0 K m PCP +[ PCP] 0 . Using this equation, a curve depicting the non-inactivation zone for the two substrates (hydrogen peroxide and PCP) was plotted and it could be used for experimental design and optimal process operation. To minimize enzyme inactivation by H 2O 2, it was determined that the concentration of H 2O 2 should be lower than 2.78 mM, regardless of the stoichiometric ratio.

The use of experimental design techniques to meet reflected color targets in pyrolytic low emissivity coatings

Low emissivity coatings are common in architectural applications and the marketplace dictates an increasingly complex set of process and optical requirements. The coatings must reflect infrared light, and, simultaneously, must have little or no visible reflected color. The first step in commercializing a new coated product is to develop a theoretical thin film stack that meets the target optical requirements while incorporating real-world materials and production requirements. The experimental design process requires a definition of the input or control factors (determined by the process and economics) and a clearly defined target response (determined by the marketplace). In the application of experimental design to thin film modeling, the control factors are the refractive indices and thicknesses of the various coating layers. The target responses are gross properties of the coated glass product, such as its reflected color and emissivity. The infinite combination of layer thicknesses and refractive indices are represented by a simple empirical model that quantifies the responses with minimal test cases or experiments. The models can then be used to find a workable solution for the design problem and provide insight into the macroscopic behavior of the color as a function of the film stack structure.

Statistical power and its subcomponents — missing and misunderstood concepts in empirical software engineering research

Recently we have witnessed a welcomed increase in the amount of empirical evaluation of Software Engineering methods and concepts. It is hoped that this increase will lead to establishing Software Engineering as a well-defined subject with a sound scientifically proven underpinning rather than a topic based upon unsubstantiated theories and personal belief. For this to happen the empirical work must be of the highest standard. Unfortunately producing meaningful empirical evaluations is a highly hazardous activity, full of uncertainties and often unseen difficulties. Any researcher can overlook or neglect a seemingly innocuous factor, which in fact invalidates all of the work. More serious is that large sections of the community can overlook essential experimental design guidelines, which bring into question the validity of much of the work undertaken to date. In this paper, the authors address one such factor — Statistical Power Analysis. It is believed, and will be demonstrated, that any body of research undertaken without considering statistical power as a fundamental design parameter is potentially fatally flawed. Unfortunately the authors are unaware of much Software Engineering research which takes this parameter into account. In addition to introducing Statistical Power, the paper will attempt to demonstrate the potential difficulties of applying it to the design of Software Engineering experiments and concludes with a discussion of what the authors believe is the most viable method of incorporating the evaluation of statistical power within the experimental design process.

Superconducting integrated circuit fabrication with low temperature ECR-based PECVD SiO/sub 2/ dielectric films

A superconducting integrated circuit fabrication process has been developed to encompass a wide range of applications such as Josephson voltage standards, VLSI scale array oscillators, SQUIDs, and kinetic-inductance-based devices. An optimal Josephson junction process requires low temperature processing for all deposition and etching steps. This low temperature process involves an electron cyclotron resonance-based plasma-enhanced chemical vapor deposition of SiO/sub 2/ films for interlayer dielectrics. Experimental design and statistical process control techniques have been used to ensure high quality oxide films. Oxide and niobium etches include endpoint detection and controlled overetch of all films. An overview of the fabrication process is presented. >

A new approach to the statistical optimisation of catalyst preparation

The statistical design of experiments is not widely used due to the apparent complexity of the procedures involved. A simplified approach, based on the methods of Taguchi, is described and is illustrated by applying it to the optimisation of the preparation of a metal-carbon catalyst. The surface area was increased from 8 to 250 m2 g−1. It is shown that the method gives five significant advantages. It enables the amount of experimentation to be significantly reduced; it provides a means for assessing the significance of synergistic effects (interactions) between variables (factors) and it can yield evidence for the existence of previously unsuspected interactions. The method has the advantage of being applicable to existing production processes by assessing the consequences of variations in operating parameters found within normal run conditions. Finally, the experimental design process is simplified and the analysis of results is facilitated by the ready availability of the required statistical techniques in commercial software for microcomputers.

A new approach to the statistical optimisation of catalyst preparation

The statistical design of experiments is not widely used due to the apparent complexity of the procedures involved. A simplified approach, based on the methods of Taguchi, is described and is illustrated by applying it to the optimisation of the preparation of a metal-carbon catalyst. The surface area was increased from 8 to 250 m 2 g −1. It is shown that the method gives five significant advantages. It enables the amount of experimentation to be significantly reduced; it provides a means for assessing the significance of synergistic effects (interactions) between variables (factors) and it can yield evidence for the existence of previously unsuspected interactions. The method has the advantage of being applicable to existing production processes by assessing the consequences of variations in operating parameters found within normal run conditions. Finally, the experimental design process is simplified and the analysis of results is facilitated by the ready availability of the required statistical techniques in commercial software for microcomputers.

Using the Taguchi Method to Enhance the Quality of Products and Processes

ABSTRACTThis article provides a brief explanation of the method developed by Genichi Taguchi and used by the Japanese to manufacture superior products. Taguchi's definition of quality and several concepts characteristic of his method are presented. A detailed explanation of Taguchi's experimental design process and an example of such an experiment are included.

Intense beam fundamental mode large-orbit gyrotron studies

Experimental and theoretical studies of a fundamental mode large-orbit gyrotron designed to produce high-power rf radiation in the TE11 mode at about 1 GHz are reported. Theoretical calculations performed as part of the experimental design process are presented. Results of initial experiments are reported in which 500–1000 MW of rf radiation was observed at frequencies 700 and 1200 MHz, consistent with theoretical expectations. The estimated eletronic efficiency of the device is about 10%. Gas cell breakdown patterns produced by the rf pulse are consistent with operation in the desired TE11 mode.