329,485 research outputs found
Combining Bayesian Approaches and Evolutionary Techniques for the Inference of Breast Cancer Networks
Gene and protein networks are very important to model complex large-scale
systems in molecular biology. Inferring or reverseengineering such networks can
be defined as the process of identifying gene/protein interactions from
experimental data through computational analysis. However, this task is
typically complicated by the enormously large scale of the unknowns in a rather
small sample size. Furthermore, when the goal is to study causal relationships
within the network, tools capable of overcoming the limitations of correlation
networks are required. In this work, we make use of Bayesian Graphical Models
to attach this problem and, specifically, we perform a comparative study of
different state-of-the-art heuristics, analyzing their performance in inferring
the structure of the Bayesian Network from breast cancer data
Enhancing the Performance of Neural Networks Through Causal Discovery and Integration of Domain Knowledge
In this paper, we develop a generic methodology to encode hierarchical
causality structure among observed variables into a neural network in order to
improve its predictive performance. The proposed methodology, called
causality-informed neural network (CINN), leverages three coherent steps to
systematically map the structural causal knowledge into the layer-to-layer
design of neural network while strictly preserving the orientation of every
causal relationship. In the first step, CINN discovers causal relationships
from observational data via directed acyclic graph (DAG) learning, where causal
discovery is recast as a continuous optimization problem to avoid the
combinatorial nature. In the second step, the discovered hierarchical causality
structure among observed variables is systematically encoded into neural
network through a dedicated architecture and customized loss function. By
categorizing variables in the causal DAG as root, intermediate, and leaf nodes,
the hierarchical causal DAG is translated into CINN with a one-to-one
correspondence between nodes in the causal DAG and units in the CINN while
maintaining the relative order among these nodes. Regarding the loss function,
both intermediate and leaf nodes in the DAG graph are treated as target outputs
during CINN training so as to drive co-learning of causal relationships among
different types of nodes. As multiple loss components emerge in CINN, we
leverage the projection of conflicting gradients to mitigate gradient
interference among the multiple learning tasks. Computational experiments
across a broad spectrum of UCI data sets demonstrate substantial advantages of
CINN in predictive performance over other state-of-the-art methods. In
addition, an ablation study underscores the value of integrating structural and
quantitative causal knowledge in enhancing the neural network's predictive
performance incrementally
Networking dimensions and performance of event management ventures in Kenya
The role of networking in the sharing of knowledge and information is well documented. What is not clear, however, are the facets of networks that best drive firm performance, and whether or not the nature of business is a factor. The purpose of this study was to examine the effect of networking dimensions on the performance of event management ventures in Kenya. The researcher conceptualised that performance of ventures was a function of networking dimensions such as network capability, network structure and network dynamics. The study adopted a covariance-based confirmatory research design that sought to confirm indicators of the four variables under study, and also to establish the causal link between networking dimensions and venture performance. A population of 313 ventures was targeted, from which a sample of 288 proprietors was drawn. Using Structural Equation Modelling as the principal analysis approach, the study established that networking dimensions positively and significantly predict events venture performance. Moreover, the measurement model confirmed that the customer and learning and growth perspectives were the main indicators of events venture performance.Keywords: event management, network capability, network dynamics, network structures, structural model, venture performanc
Causation versus Prediction: Comparing Causal Discovery and Inference with Artificial Neural Networks in Travel Mode Choice Modeling
This study compares the performance of a causal and a predictive model in
modeling travel mode choice in three neighborhoods in Chicago. A causal
discovery algorithm and a causal inference technique were used to extract the
causal relationships in the mode choice decision making process and to estimate
the quantitative causal effects between the variables both directly from
observational data. The model results reveal that trip distance and vehicle
ownership are the direct causes of mode choice in the three neighborhoods.
Artificial neural network models were estimated to predict mode choice. Their
accuracy was over 70%, and the SHAP values obtained measure the importance of
each variable. We find that both the causal and predictive modeling approaches
are useful for the purpose they serve. We also note that the study of mode
choice behavior through causal modeling is mostly unexplored, yet it could
transform our understanding of the mode choice behavior. Further research is
needed to realize the full potential of these techniques in modeling mode
choice
Manufacturer-supplier relationships and service performance in service triads
Purpose - The purpose of this paper is to explore the role of the manufacturer-supplier relationship in service performance within service triads. Design/methodology/approach - An abductive case-research approach was adopted, using three embedded cases and 26 interviews in complex, multilevel manufacturer-supplier relationships within the same service network. Cannon and Perreault's (1999) multidimensional relationship framework was deployed to achieve granular and nuanced insight. Findings - This study corroborates the idea that relational relationships within service triads and servitization improve performance. The role of each relationship dimension in service performance is discerned and their interplay is captured in an analytic model. Information exchange, supplier relationship-specific adaptations, and the degree of formalization of the relationship directly influence performance, while cooperative norms and operational linkages are further back in the causal ordering. The study also highlights the importance of contingent factors (the size of the service site, the proportion of its revenues coming from service contract activities) and how they affect the relationship dimensions. Research limitations/implications - The work was conducted in one network and the findings were generalized to theory rather than additional empirical settings. Originality/value - This study is the first to derive a contextualized causal ordering of the Cannon and Perreault (1999) framework of relationship connectors and link it with service performance
Artificial neural network analysis of teachers��� performance against thermal comfort
This is an accepted manuscript of an article published by Emerald in International Journal of Building Pathology and Adaptation on 17/04/2020, available online at: https://doi.org/10.1108/IJBPA-11-2019-0098
The accepted manuscript may differ from the final published version.Purpose: The impact of thermal comfort in educational buildings continues to be
of major importance in both the design and construction phases. Given this, it is
also equally important to understand and appreciate the impact of design decisions
on post-occupancy performance, particularly on staff and students. This study aims
to present the effect of IEQ on teachers��� performance. This study would provide
thermal environment requirements to BIM-led school refurbishment projects.
Design: This paper presents a detailed investigation into the direct impact of
thermal parameters (temperature, relative humidity and ventilation rates) on
teacher performance. In doing so, the research methodological approach combines
explicit mixed-methods using questionnaire surveys and physical measurements of
thermal parameters to identify correlation and inference. It was conducted through
a single case study using a technical college based in Saudi Arabia. Findings:
Findings from this work were used to develop a model using an Artificial Neural
Network to establish causal relationships. Research findings indicate an optimal
temperature range between 23��C and 25��C, with a 65% relative humidity and
0.4m/s ventilation rate. This ratio delivered optimum results for both comfort and
performance
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