When do Models Generalize? A Perspective from Data-Algorithm Compatibility

One of the major open problems in machine learning is to characterize generalization in the overparameterized regime, where most traditional generalization bounds become inconsistent (Nagarajan and Kolter, 2019). In many scenarios, their failure can be attributed to obscuring the crucial interplay between the training algorithm and the underlying data distribution. To address this issue, we propose a concept named compatibility, which quantitatively characterizes generalization in a both data-relevant and algorithm-relevant manner. By considering the entire training trajectory and focusing on early-stopping iterates, compatibility exploits the data and the algorithm information and is therefore a more suitable notion for generalization. We validate this by theoretically studying compatibility under the setting of solving overparameterized linear regression with gradient descent. Specifically, we perform a data-dependent trajectory analysis and derive a sufficient condition for compatibility in such a setting. Our theoretical results demonstrate that in the sense of compatibility, generalization holds with significantly weaker restrictions on the problem instance than the previous last iterate analysis

Dynamic Tolling in Arc-based Traffic Assignment Models

Tolling in traffic networks offers a popular measure to minimize overall congestion. Existing toll designs primarily focus on congestion in route-based traffic assignment models (TAMs), in which travelers make a single route selection from their source to destination. However, these models do not reflect real-world traveler decisions because they preclude deviations from a chosen route, and because the enumeration of all routes is computationally expensive. To address these limitations, our work focuses on arc-based TAMs, in which travelers sequentially select individual arcs (or edges) on the network to reach their destination. We first demonstrate that marginal pricing, a tolling scheme commonly used in route-based TAMs, also achieves socially optimal congestion levels in our arc-based formulation. Then, we use perturbed best response dynamics to model the evolution of travelers' arc selection preferences over time, and a marginal pricing scheme to the social planner's adaptive toll updates in response. We prove that our adaptive learning and marginal pricing dynamics converge to a neighborhood of the socially optimal loads and tolls. We then present empirical results that verify our theoretical claims.Comment: 18 pages, 4 figures, 2 tables. arXiv admin note: text overlap with arXiv:2304.0470

A Mobile Robot Generating Video Summaries of Seniors' Indoor Activities

We develop a system which generates summaries from seniors' indoor-activity videos captured by a social robot to help remote family members know their seniors' daily activities at home. Unlike the traditional video summarization datasets, indoor videos captured from a moving robot poses additional challenges, namely, (i) the video sequences are very long (ii) a significant number of video-frames contain no-subject or with subjects at ill-posed locations and scales (iii) most of the well-posed frames contain highly redundant information. To address this problem, we propose to \hl{exploit} pose estimation \hl{for detecting} people in frames\hl{. This guides the robot} to follow the user and capture effective videos. We use person identification to distinguish a target senior from other people. We \hl{also make use of} action recognition to analyze seniors' major activities at different moments, and develop a video summarization method to select diverse and representative keyframes as summaries.Comment: accepted by MobileHCI'1

A Multisampling Reporter System for Monitoring MicroRNA Activity in the Same Population of Cells

MicroRNAs (miRNAs) downregulate gene expression by binding to the partially complementary sites in the 3′ untranslated region (UTR) of target mRNAs. Several methods, such as Northern blot analysis, quantitative real-time RT-PCR, microarray, and the luciferase reporter system, are commonly used to quantify the relative level or activity of miRNAs. The disadvantage of these methods is the requirement for cell lysis, which means that several sets of wells/dishes of cells must be prepared to monitor changes in miRNA activity in time-course studies. In this study, we developed a multisampling reporter system in which two secretable bioluminescence-generating enzymes are employed, one as a reporter and the other as an internal control. The reporters consist of a pair of vectors containing the Metridia luciferase gene, one with and one without a duplicated miRNA targeting sequence at their 3′UTR, while the other vector coding for the secreted alkaline phosphatase gene is used as an internal control. This method allows miRNA activity to be monitored within the same population of cells over time by withdrawing aliquots of the culture medium. The practicability and benefits of this system are addressed in this report

Scientific and Regulatory Perspective on Monoclonal Antibody Biosimilars

Similar biotherapeutic products (SBPs), also called biosimilars, exhibit similar biological and clinical properties to authorized reference products. Biosimilars, including small molecules like erythropoietin and complex macromolecules like monoclonal antibodies (mAbs), have been used extensively in disease treatment. Monoclonal antibody biosimilars have gradually become a dominant development in the global pharmaceutical industry since their patents or data protection have been expired or nearing expiration. Since the mAb biosimilars are complex biological macromolecules with various post-translation modifications, it is important to evaluate whether these tiny differences significantly affect the quality. From a regulatory perspective, the comparability study needs to be performed to demonstrate that the quality, safety, and efficacy are similar to the biological reference. Based on these comprehensive comparative results, the indicated extrapolation might be acceptable. Post-market surveillance is also required because of unexpected biological variation caused by slightly different manufacturing processes. This chapter presents the scientific and regulatory considerations for monoclonal antibody biosimilar products for manufactures and for the regulatory authorities to administrate wisely and comprehensively

The making of power shortage:The sociotechnical imaginary of nationalist high modernism and its pragmatic rationality in electricity planning in Taiwan

High modernism, the dominant sociotechnical imagination in postwar Taiwan, manifested in tacit answers to the questions of what a better society would look like and the most pragmatic and viable approach to make the particular dreamed-of future become reality. This article explores the exclusion of alternative energy futures brought about by a high modernist imaginary. This imaginary underlies a strategy of emphasizing shortage at present and prosperity in the future—as long as the current shortage is solved in a reliable way. Focusing on the contention over energy supply between 2011 and 2015, this article provides an analysis of how power shortages are presented in discursive ambiguity, how the claimed crisis over the electricity shortage moves to the center of public debate via the institutional practices of power rationing, and how its public authority is established through collective witness. Renewable energy is continually represented as an “immature” and “unviable” technology when it comes to satisfying the nation’s need, through particular routinized practices in the calculation of “reserve margins” in electricity planning and the collective witnessing of (limited) operating reserves. We argue that both of these come with their own assumptions and political implications and therefore invite scrutiny