scholarly journals Comparing Functional Analysis Methods for Product Dissection Tasks

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Joran W. Booth ◽  
Tahira N. Reid ◽  
Claudia Eckert ◽  
Karthik Ramani
Keyword(s):  
Functional Analysis ◽  
Energy Flow ◽  
Prior Experience ◽  
Qualitative Difference ◽  
Top Down ◽  
Identification Methods ◽  
Future Studies ◽  
Core Concepts ◽  
Power Drill ◽  
Function Identification

The purpose of this study is to begin to explore which function identification methods work best for specific tasks. We use a three-level within-subject study (n = 78) to compare three strategies for identifying functions: energy-flow, top-down, and enumeration. These are tested in a product dissection task with student engineers who have minimal prior experience. Participants were asked to dissect a hair dryer, power drill, and toy dart gun and generate function trees to describe how these work. The function trees were evaluated with several metrics including the total number of functions generated, the number of syntactical errors, and the number of unique (relevant and nonredundant) functions. We found no statistical, practical, or qualitative difference between the trees produced by each method. This suggests that the cognitive load for this task for novices is high enough to obscure any real differences between methods. We also found some generalized findings through surveys that the most difficult aspects of using functional decomposition include identifying functions, choosing function verbs, and drawing the diagram. Together, this may also mean that for novice engineers, the method does not matter as much as core concepts such as identifying functions and structuring function diagrams. This also indicates that any function identification method may be used as a baseline for comparison between novices in future studies.

Evaluating the Bottom-Up Method for Functional Decomposition in Product Dissection Tasks

2014 ◽  
Author(s):  
Joran W. Booth ◽  
Abihnav K. Bhasin ◽  
Tahira Reid ◽  
Karthik Ramani
Keyword(s):  
Prior Work ◽  
Top Down ◽  
Specific Design ◽  
Bottom Up ◽  
Functional Decomposition ◽  
Identification Methods ◽  
Future Studies ◽  
Statistical Support ◽  
Prior Literature ◽  
Function Identification

The purpose of this study is to continue to explore which function identification methods work best for specific design tasks. Prior literature describes the top-down and bottom-up approaches as equivalent methods for functional decomposition. Building on our prior work, this study tests the bottom-up method against the top-down and enumeration methods. We used a 3-factor within-subject study (n=136). While most of our diagram-oriented metrics were not statistically different, we found statistical support that: 1.) students reported that the dissection activity was more useful when using bottom-up, and 2.) that student engineers committed many more syntax errors when using the bottom-up method (by listing parts instead of functions). We believe that both these results are due to the increased focus on individual parts. We do not know if an increased attention to the parts would increase novelty or fixation, and recommend future studies to find out.

Understanding Abstraction in Design: A Comparison of Three Functional Analysis Methods for Product Dissection

2013 ◽  
Author(s):  
Joran W. Booth ◽  
Tahira Reid ◽  
Karthik Ramani
Keyword(s):  
Functional Analysis ◽  
Formal Methods ◽  
Design Process ◽  
Generate Function ◽  
Energy Flow ◽  
Statistical Difference ◽  
Top Down ◽  
Levels Of Abstraction ◽  
Power Drill ◽  
Measures Of Effectiveness

In design classes, functional analysis is a process that is typically used to assist students with identifying essential functions to aid in the development of their concepts. However, it has been observed that students sometimes struggle with this part of the design process. In this study, a group of 26 students were studied in a 3-level within-subject study (n = 78) to determine which of three common functional analysis approaches (i.e. top-down, energy-flow, and unstructured) was most effective. Participants were asked to dissect a hair dryer, power drill, and NERF pistol and generate function trees describing how these work. Measures of effectiveness include the number of functions generated, the number of errors, the number of levels of abstraction represented in the tree, and the number of unique subsystems and functions identified. No statistical difference between the approaches was found, and there was also no practical difference between the approaches. These results suggest that for novice engineers, there is no difference between methods used. This possibly indicates that for novice engineers, formal methods may not be any more effective than an unstructured approach.

Is pelagic top-down control in lakes augmented by benthic energy pathways?

2005 ◽  
Vol 62 (6) ◽  
pp. 1422-1431 ◽  
Author(s):  
M Jake Vander Zanden ◽  
Timothy E Essington ◽  
Yvonne Vadeboncoeur
Keyword(s):  
Food Web ◽  
Energy Flow ◽  
Standing Stock ◽  
Fold Increase ◽  
Trophic Dynamics ◽  
Prey Fish ◽  
Top Down ◽  
Food Web Structure ◽  
Contrast Analysis ◽  
Dynamic Perspective

Modern food web studies are typically conducted from a trophic dynamic perspective that focuses on combined roles of top-down and bottom-up forces in regulating food web structure. Recognition of spatial food web subsidies in diverse ecosystems highlights the importance of energy flow as a foundation for understanding trophic dynamics. Here, we consider how different energy flow configurations might affect trophic dynamics in north-temperate lakes. A literature review revealed that littoral piscivores exert top-down control on prey fishes. In contrast, analysis of littoral predator diets indicated extensive omnivory and heavy reliance on zoobenthic prey. We explored this uncoupling between trophic dynamics (piscivores regulate prey fish) and energy flow (zoobenthos in piscivore diets) using a biomass dynamic model. This model compared top-down impacts of a piscivore on prey fishes under two scenarios: consumption of prey fish only and consumption of prey fish plus zoobenthos. The model predicted that elimination of zoobenthivory leads to a 50% reduction in piscivore standing stock and concomitant 2.5-fold increase in prey fish abundance (i.e., zoobenthivory plays a key role in mediating pelagic top-down control). These results highlight the role of benthic–pelagic linkages in regulating trophic dynamics and underscore the value of whole-ecosystem approaches to the study of food webs.

Empirical Studies of Functional Decomposition in Early Design

2015 ◽  
Author(s):  
Joran W. Booth ◽  
Abhinav K. Bhasin ◽  
Tahira N. Reid ◽  
Karthik Ramani
Keyword(s):  
Energy Flow ◽  
Empirical Studies ◽  
Team Communication ◽  
Concept Generation ◽  
Top Down ◽  
Design Quality ◽  
Functional Decomposition ◽  
Early Design ◽  
Final Design ◽  
Function Diagram

This paper explores functional decomposition in early design. In the first part of this study, we explore how the three most common methods (top-down, energy-flow, enumeration) affect concept generation for novice design teams (n=25). We found that nearly all the features in the final concept could be mapped to the function diagram, though not all the functions mapped to the actual concept. This suggests that there is not much change in system functionality between these two phases, despite being separated by a few weeks. We also found that teams who used top-down and energy-flow performed nearly the same, and teams who used enumeration performed worse than those who used energy-flow. Based on these results, we recommend using either top-down or energy-flow, but not enumeration in early design. We also observed that teams used the diagramming process to reach a consensus and support team communication. The second part of this study evaluates design reports (n=78) from industry engineers taking a distance learning design course. Even though roughly half of the reports used functional decomposition, there was no correlation between using functional decomposition and final design quality as measured by various grade components. We also observed that half of the function diagrams were tree diagrams. This supports prior findings that a top-down, tree-based approach is more intuitive for engineers. Together, these results suggest that functional decomposition is helpful for team communication, but show no direct correlation with design outcome. We also recommend training strategies for teaching decomposition based on differences between the two datasets.

scholarly journals The impact of action effects on infants’ predictive gaze shifts for a non-human grasping action at 7-, 11-, and 18 months

2021 ◽  
Author(s):  
Maurits Adam ◽  
Christian Gumbsch ◽  
Martin V. Butz ◽  
Birgit Elsner
Keyword(s):  
Prior Knowledge ◽  
Prior Experience ◽  
Gaze Behavior ◽  
Top Down ◽  
Complex Interplay ◽  
Goal Object ◽  
Bottom Up ◽  
Action Effect ◽  
Event Based ◽  
The Impact

During the observation of goal-directed actions, infants usually predict the goal when the action and the agent are familiar, but they do not as easily predict the goal when the action or the agent are unfamiliar. Recent theoretical accounts suggest that predictive gaze behavior relies on a complex interplay between bottom-up- (e.g., agency cues) and top- down information (e.g., prior experience with the action), depending on an observer’ prior knowledge about the unfolding action event. Based on these accounts, we hypothesized that during the observation of grasping actions performed by a mechanical claw, younger infants would need agency cues to show predictive gaze behavior, whereas older infants would be able to show predictive gaze behavior regardless of agency cues. Therefore, we presented 7-, 11-, and 18-month-old infants with videos of a mechanical claw that repeatedly approached and grasped a goal object and then either did or did not produce a salient action effect. The 7-month-olds were not predictive regardless of the salient action effect, the 11-month-olds were only predictive when the salient action effect was presented, and the 18-month-olds were predictive regardless of the salient action effect. These results therefore support the idea of a complex interplay between bottom-up and top-down information as a crucial factor for the production of predictive gaze behavior during the observation of goal-directed actions performed by mechanical agents.

scholarly journals Statistical mechanics of neocortical interactions: EEG eigenfunctions of short-term memory

2000 ◽  
Vol 23 (3) ◽  
pp. 403-405 ◽  
Author(s):  
Lester Ingber
Keyword(s):  
Statistical Mechanics ◽  
Short Term Memory ◽  
Probability Distributions ◽  
Regional Scale ◽  
Top Down ◽  
Short Term ◽  
Bottom Up ◽  
Term Memory ◽  
Future Studies ◽  
Scalp Eeg

This commentary focuses on how bottom-up neocortical models can be developed into eigenfunction expansions of probability distributions appropriate to describe short-term memory in the context of scalp EEG. The mathematics of eigenfunctions are similar to the top-down eigenfunctions developed by Nunez, despite different physical manifestations. The bottom-up eigenfunctions are at the local mesocolumnar scale, whereas the top-down eigenfunctions are at the global regional scale. Our respective approaches have regions of substantial overlap, and future studies may expand top-down eigenfunctions into the bottom-up eigenfunctions, yielding a model of scalp EEG expressed in terms of columnar states of neocortical processing of attention and short-term memory.

scholarly journals A Search Advantage for Horizontal Targets in Dynamic Displays

i-Perception ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 204166952110046
Author(s):  
Ian M. Thornton ◽  
Quoc C. Vuong ◽  
Karin S. Pilz
Keyword(s):  
Visual Search ◽  
Change Detection ◽  
Visual Processing ◽  
Display Size ◽  
Top Down ◽  
Future Studies ◽  
Strong Orientation ◽  
Dynamic Target ◽  
Underlying Mechanisms ◽  
Lines Of Evidence

Several lines of evidence point to the existence of a visual processing advantage for horizontal over vertical orientations. We investigated whether such a horizontal advantage exists in the context of top-down visual search. Inspired by change detection studies, we created displays where a dynamic target -- a horizontal or a vertical group of five dots that changed contrast synchronously -- was embedded within a randomly flickering grid of dots. The display size (total dots) varied across trials, and the orientation of the target was constant within interleaved blocks. As expected, search was slow and inefficient. Importantly, participants were almost a second faster finding horizontal compared to vertical targets. They were also more efficient and more accurate during horizontal search. Such findings establish that the attentional templates thought to guide search for known targets can exhibit strong orientation anisotropies. We discuss possible underlying mechanisms and how these might be explored in future studies.

scholarly journals Calculation Methods for Construction Material Stocks: A Systematic Review

2021 ◽  
Vol 11 (14) ◽  
pp. 6612
Author(s):  
Usman Nasir ◽  
Ruidong Chang ◽  
Hossein Omrany
Keyword(s):  
Statistical Data ◽  
Construction Material ◽  
Research Area ◽  
Embodied Energy ◽  
Small Scale ◽  
Calculation Methods ◽  
Top Down ◽  
Bottom Up ◽  
Future Studies ◽  
Socio Economic Factors

This paper aims to critically review the current body of literature relating to the calculation methods of construction material stock. To this end, this study adopts a systematic literature review technique in order to identify the relevant studies. The findings revealed that the bottom-up and top-down methodologies were commonly employed by the reviewed studies. Based on the findings, it is recommended that the bottom-up approach should be utilized when dealing with small-scale areas or where more accurate results are required. The top-down method should be used wherein the research area is large, and the results could be estimated based upon assumptions and statistical data. Similarly, the demand-driven methodology should be used to find the material stock accumulation due to socio-economic factors. The study also found that the material stock results can be used as data for other research, such as waste management and embodied energy. Further, this paper proposes a conceptual framework to ease the process of calculating construction material stocks in different projects. The outcomes of this research shall be beneficial for future studies that explore the literature connected to the construction material stock and recommend methods and techniques that should be used to quantify the material stock.

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