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Industries rely heavily on resources. Resource scarcity and price fluctuations can significantly affect business outcomes. Traditional industries rely on tangible materials. The automobile industry, for example, uses iron, aluminum, glass, and other physical resources. In recent years, we have seen a shift toward increased use of intangible resources, like patents or information.1 The Internet economy is not the first to rely on intangible resources, but it does one thing differently. It keeps these resources at the back of the stage – in the shadows.
I graduated from law school in the mid-1990s with a concentration in intellectual property law. I was interested in the new economy; in technology; in legal change. After law school, I moved from the United States to Israel, where I started working in a leading law firm in Tel-Aviv. The law firm was as old school as could be, and so were many of its clients. I hoped to work on intellectual property cases, but – to my dismay – the law firm assigned me to work on antitrust cases. Antitrust was the antithesis of where I expected to start my career. I viewed it as the law of brick and mortar. Indeed, antitrust law grew regulating the old economy; railroad and oil companies dominate the classic antitrust court cases.1
Most parents came to hear my talks because they were desperate. They wanted to know what to do to re-engage with their kids. Without fail, when I switched to my slide that listed the self-help methods, parents took out their phones to take pictures of that slide. I suggested using apps limiting time on devices. I talked about creating device-free times and zones during mealtimes or certain hours before bed. I talked about the importance of modeling. When parents spend a lot of time on their phones, so will children once they get them. I spoke at length and offered a list of strategies. I wanted badly to offer hope. But by 2019, I felt discouraged. I was no longer a believer. I still felt these methods could make a difference, especially when the children were on board. But I realized that self-help could only solve a small part of the problem.
In 1998, I worked in a law firm in midtown Manhattan. I spent too many long days and nights at my desk, unsurprisingly gaining weight. I wanted to diet, but it turned out to be a bigger challenge than I had expected. Until then, I had lived most of my life in Israel. The Israeli diet is very different from the American diet. I grew up regularly eating vegetable salads with light dressings. My American friends are often amazed when they realize my family and I still eat vegetables for breakfast. I recall, then, my disappointment as I tried out many lunch places around my office. These lunch joints offered mainly sandwiches. When I spotted a dish that resembled a salad it usually floated in mayonnaise.
Neurotechnology has been applied to gain insights on creativity-related cognitive factors. Prior research has identified relations between cognitive factors and creativity qualitatively; while quantitative relations, such as the relative importance of cognitive factors and creativity, have not been fully determined. Therefore, taking the creative design process as an example, this study using electroencephalography (EEG) aims to objectively identify how creativity-related cognitive factors of retrieval, recall, association, and combination contribute to creativity. The theoretical basis for an EEG-based decoding method to objectively identify which cognitive factors occur in a creative process is developed. Thirty participants were recruited for a practical study to verify the reliability of the decoding method. Based on the methodology, relationships between the relative importance level of the cognitive factor and creative output quality levels were detected. Results indicated that the occurrence of recall and association are reported with a high reliability level by the decoding method. The results also indicated that association is the dominant cognitive factor for higher creative output quality levels. Recall is the dominant cognitive factor for lower creative output quality levels.
We create a new tactile recording system with which we develop a three-axis fingernail-color sensor that can measure a three-dimensional force applied to fingertips by observing the change of the fingernail’s color. Since the color change is complicated, the relationships between images and three-dimensional forces were assessed using convolution neural network (CNN) models. The success of this method depends on the input data size because the CNN model learning requires big data. Thus, to efficiently obtain big data, we developed a novel measuring device, which was composed of an electronic scale and a load cell, to obtain fingernail images with 0$^\circ$ to 360$^\circ$ directional tangential force. We performed a series of evaluation experiments to obtain movies of the color changes caused by the three-axis forces and created a data set for the CNN models by transforming the movies to still images. Although we produced a generalized CNN model that can evaluate the images of any person’s fingernails, its root means square error (RMSE) exceeded both the whole and individual models, and the individual models showed the smallest RMSE. Therefore, we adopted the individual models, which precisely evaluated the tangential-force direction of the test data in an $F_x$-$F_y$ plane within around $\pm$2.5$^\circ$ error at the peak points of the applied force. Although the fingernail-color sensor possessed almost the same level of accuracy as previous sensors for normal-force tests, the present fingernail-color sensor acts as the best tangential sensor because the RMSE obtained from tangential-force tests was around 1/3 that of previous studies.
Innovative, responsible data use is a critical need in the global response to the coronavirus disease-2019 (COVID-19) pandemic. Yet potentially impactful data are often unavailable to those who could utilize it, particularly in data-poor settings, posing a serious barrier to effective pandemic mitigation. Data challenges, a public call-to-action for innovative data use projects, can identify and address these specific barriers. To understand gaps and progress relevant to effective data use in this context, this study thematically analyses three sets of qualitative data focused on/based in low/middle-income countries: (a) a survey of innovators responding to a data challenge, (b) a survey of organizers of data challenges, and (c) a focus group discussion with professionals using COVID-19 data for evidence-based decision-making. Data quality and accessibility and human resources/institutional capacity were frequently reported limitations to effective data use among innovators. New fit-for-purpose tools and the expansion of partnerships were the most frequently noted areas of progress. Discussion participants identified building capacity for external/national actors to understand the needs of local communities can address a lack of partnerships while de-siloing information. A synthesis of themes demonstrated that gaps, progress, and needs commonly identified by these groups are relevant beyond COVID-19, highlighting the importance of a healthy data ecosystem to address emerging threats. This is supported by data holders prioritizing the availability and accessibility of their data without causing harm; funders and policymakers committed to integrating innovations with existing physical, data, and policy infrastructure; and innovators designing sustainable, multi-use solutions based on principles of good data governance.
In this paper, we study quasi-metric spaces using domain theory. Given a quasi-metric space (X,d), we use $({\bf B}(X,d),\leq^{d^{+}}\!)$ to denote the poset of formal balls of the associated quasi-metric space (X,d). We introduce the notion of local Yoneda-complete quasi-metric spaces in terms of domain-theoretic properties of $({\bf B}(X,d),\leq^{d^{+}}\!)$. The manner in which this definition is obtained is inspired by Romaguera–Valero theorem and Kostanek–Waszkiewicz theorem. Furthermore, we obtain characterizations of local Yoneda-complete quasi-metric spaces via local nets in quasi-metric spaces. More precisely, we prove that a quasi-metric space is local Yoneda-complete if and only if every local net has a d-limit. Finally, we prove that every quasi-metric space has a local Yoneda completion.
Customer preference modelling has been widely used to aid engineering design decisions on the selection and configuration of design attributes. Recently, network analysis approaches, such as the exponential random graph model (ERGM), have been increasingly used in this field. While the ERGM-based approach has the new capability of modelling the effects of interactions and interdependencies (e.g., social relationships among customers) on customers’ decisions via network structures (e.g., using triangles to model peer influence), existing research can only model customers’ consideration decisions, and it cannot predict individual customer’s choices, as what the traditional utility-based discrete choice models (DCMs) do. However, the ability to make choice predictions is essential to predicting market demand, which forms the basis of decision-based design (DBD). This paper fills this gap by developing a novel ERGM-based approach for choice prediction. This is the first time that a network-based model can explicitly compute the probability of an alternative being chosen from a choice set. Using a large-scale customer-revealed choice database, this research studies the customer preferences estimated from the ERGM-based choice models with and without network structures and evaluates their predictive performance of market demand, benchmarking the multinomial logit (MNL) model, a traditional DCM. The results show that the proposed ERGM-based choice modelling achieves higher accuracy in predicting both individual choice behaviours and market share ranking than the MNL model, which is mathematically equivalent to ERGM when no network structures are included. The insights obtained from this study further extend the DBD framework by allowing explicit modelling of interactions among entities (i.e., customers and products) using network representations.
This book offers a mathematical foundation for modern cryptography. It is primarily intended as an introduction for graduate students. Readers should have basic knowledge of probability theory, but familiarity with computational complexity is not required. Starting from Shannon's classic result on secret key cryptography, fundamental topics of cryptography, such as secret key agreement, authentication, secret sharing, and secure computation, are covered. Particular attention is drawn to how correlated randomness can be used to construct cryptographic primitives. To evaluate the efficiency of such constructions, information-theoretic tools, such as smooth min/max entropies and information spectrum, are developed. The broad coverage means the book will also be useful to experts as well as students in cryptography as a reference for information-theoretic concepts and tools.
Statistical and machine learning methods have many applications in the environmental sciences, including prediction and data analysis in meteorology, hydrology and oceanography; pattern recognition for satellite images from remote sensing; management of agriculture and forests; assessment of climate change; and much more. With rapid advances in machine learning in the last decade, this book provides an urgently needed, comprehensive guide to machine learning and statistics for students and researchers interested in environmental data science. It includes intuitive explanations covering the relevant background mathematics, with examples drawn from the environmental sciences. A broad range of topics is covered, including correlation, regression, classification, clustering, neural networks, random forests, boosting, kernel methods, evolutionary algorithms and deep learning, as well as the recent merging of machine learning and physics. End‑of‑chapter exercises allow readers to develop their problem-solving skills, and online datasets allow readers to practise analysis of real data.
Three areas where machine learning (ML) and physics have been merging: (a) Physical models can have computationally expensive components replaced by inexpensive ML models, giving rise to hybrid models. (b) In physics-informed machine learning, ML models can be solved satisfying the laws of physics (e.g. conservation of energy, mass, etc.) either approximately or exactly. (c) In forecasting, ML models can be combined with numerical/dynamical models under data assimilation.
In the field of content generation by machine, the state-of-the-art text-to-image model, DALL⋅E, has advanced and diverse capacities for the combinational image generation with specific textual prompts. The images generated by DALL⋅E seem to exhibit an appreciable level of combinational creativity close to that of humans in terms of visualizing a combinational idea. Although there are several common metrics which can be applied to assess the quality of the images generated by generative models, such as IS, FID, GIQA, and CLIP, it is unclear whether these metrics are equally applicable to assessing images containing combinational creativity. In this study, we collected the generated image data from machine (DALL⋅E) and human designers, respectively. The results of group ranking in the Consensual Assessment Technique (CAT) and the Turing Test (TT) were used as the benchmarks to assess the combinational creativity. Considering the metrics’ mathematical principles and different starting points in evaluating image quality, we introduced coincident rate (CR) and average rank variation (ARV) which are two comparable spaces. An experiment to calculate the consistency of group ranking of each metric by comparing the benchmarks then was conducted. By comparing the consistency results of CR and ARV on group ranking, we summarized the applicability of the existing evaluation metrics in assessing generative images containing combinational creativity. In the four metrics, GIQA performed the closest consistency to the CAT and TT. It shows the potential as an automated assessment for images containing combinational creativity, which can be used to evaluate the images containing combinational creativity in the relevant task of design and engineering such as conceptual sketch, digital design image, and prototyping image.
A good model aims to learn the underlying signal without overfitting (i.e. fitting to the noise in the data). This chapter has four main parts: The first part covers objective functions and errors. The second part covers various regularization techniques (weight penalty/decay, early stopping, ensemble, dropout, etc.) to prevent overfitting. The third part covers the Bayesian approach to model selection and model averaging. The fourth part covers the recent development of interpretable machine learning.
Kernel methods provide an alternative family of non-linear methods to neural networks, with support vector machine being the best known among kernel methods. Almost all linear statistical methods have been non-linearly generalized by the kernel approach, including ridge regression, linear discriminant analysis, principal component analysis, canonical correlation analysis, and so on. The kernel method has also been extended to probabilisitic models, for example Gaussian processes.
Under unsupervised learning, clustering or cluster analysis is first studied. Clustering methods are grouped into non-hierarchical (including K-means clustering) and hierarchical clustering. Self-organizing maps can be used as a clustering method or as a discrete non-linear principal component analysis method. Autoencoders are neural network models that can be used for non-linear principal component analysis. Non-linear canonical correlation analysis can also be performed using neural network models.
NN models with more hidden layers than the traditional NN are referred to as deep neural network (DNN) or deep learning (DL) models, which are now widely used in environmental science. For image data, the convolutional neural network (CNN) has been developed, where in convolutional layers, a neuron is only connected to a small patch of neurons in the preceding layer, thereby greatly reducing the number of model weights. Popular architectures of DNN include the encoder-decoder and U-net models. For time series modelling, the long short-term memory (LSTM) network and temporal convolutional network have been developed. Generative adversarial network (GAN) produces highly realistic fake data.
Principal component analysis (PCA), a classical method for reducing the dimensionality of multivariate datasets, linearly combines the variables to generate new uncorrelated variables that maximize the amount of variance captured. Rotation of the PCA modes is commonly performed to provide more meaningful interpretation. Canonical correlation analysis (CCA) is a generalization of correlation (for two variables) to two groups of variables, with CCA finding modes of maximum correlation between the two groups. Instead of maximum correlation, maximum covariance analysis extracts modes with maximum covariance.
Forecast verification evaluates the quality of the forecasts made by a model, using a variety of forecast scores developed for binary classes, multiple classes, continuous variables and probabilistic forecasts. Skill scores estimate a model’s skill relative to a reference model or benchmark. Problems such as spurious skills and extrapolation with new data are discussed. Model bias in the output predicted by numerical models is alleviated by post-processing methods, while output from numerical models with low spatial resolution is enhanced by downscaling methods, especially in climate change studies.